The compression correction for PoreXpert is a separate application, PoreXpand, that is launched separately.
PoreXpand can be purchased separately by contacting us via support@porexpert.com or the contact us page on the website. The compression correction only works with Thermo Fisher and Micromeritics data files. The Thermo Fisher compression correction can read all of the required data from the data file exported to Pore-Cor or to PoreXpert. For assistance with exporting data from a Thermo Fisher instrument, follow the instructions provided here. The compression correction will not work with data that has already been corrected for compressibility by the Thermo Fisher SOLID software.
The compression correction cannot be performed completely automatically; it requires input from the user to ensure that the compression correction is not over correcting the intrusion curve.
The compression correction works by calculating the bulk modulus of the sample which will change the shape of the high pressure intrusion and extrusion curves (as detailed in the background science). The high pressure intrusion curve typically indicates intrusion of mercury into the sample at high pressure, although there are other effects that can cause this simulated intrusion effect. The experimental apparatus consists of a glass sample chamber sealed with a metal cap at high pressures the glass sample chamber can expand because of the pressure exerted by the mercury. The mercury can also be compressed at extremely high pressures allowing more mercury into the sample chamber. Both of these effects can be corrected for by using a blank chamber analysis performed using identical conditions.
PoreXpand exports the data in an appropriate format for use with PoreXpert, providing PoreXpert with details about the intrusion fluid and providing the corrected intrusion and extrusion curves for modelling. When opening a data file that has been exported by PoreXpand, the description of the sample will additionally show a message indicating that the data has been corrected for compressibility by PoreXpand, which is also added to the PDF reports. The next figure shows a sample that has been corrected for compressibility by PoreXpand and has been opened by PoreXpert. The data file has not been trimmed to remove any possible edge effects - this can also be done in PoreXpand.
Sampling screen showing a mercury porosimetry curve corrected using PoreXpand.
The mathematics behind the correction method has been published by us (Gane et al., 1996), and further details are given in the following background science section.