Analysis Conditions

(or click the Analysis Conditions tab when in Advanced presentation option)

Analysis conditions specify the parameters used to guide an analysis.

Analysis Conditions
Field or Button Description
Analysis Conditions
[text box]
Displays the description of the file. If this is a new file, the description specified in sample defaults is displayed.
Analysis gas [text box] The gas to be used for analysis gas (helium is recommended).

Analysis method
[selection]

For the FoamPyc application only.

  • Standard. Select Record equilibration data then enter the criteria (if recording equilibration data).

Enter the cell wall density.

  • Correction using cell dimensions. Measures the closed cell fraction and corrects for the cells damaged while cutting the sample to the necessary size and shape. This is accomplished by using either the average cell diameter or the cell chord length (as defined in ASTM method D‑6226‑15) and the measurements of the sample to determine the volume of the cut cells. This volume is deducted from the total volume of the open cells measured by the pycnometer.
  • Correction by recutting sample. Corrects for the cut cells by using two separate measurements. For the 2nd measurement, the sample is recut to double the amount of cut surface. The observed difference in cut open cell volume is applied as a correction to the initial measured volume. This method offers the distinct advantage that no assumptions are needed about the relative amounts of open and closed cells.
  • No correction. Does not correct for cut cells. It is used for materials with predominantly open cells where good accuracy can be achieved without correction. The accuracy level deteriorates as the percentage of closed cells increases.

Enter the initial and final pressure, and the pressure increment.

  • Compressibility test. The fill pressure is increased incrementally over the sample with each repeat of the P1,P2 cycle (where P1 is the initial pressure to which the sample is charged, and P2 the final pressure after expansion). The apparent variation of the measured sample volume with the average pressure is determined. This test is an approximate indication. It is not intended to be an exact measure of the volume compressibility.

Enter the Low pressure and the Fracture pressure.

  • Cell fracture test. A perfectly rigid foam is assumed. First, a P1,P2 cycle is performed at the lower of two specified P1 pressures, and the results stored. A second cycle is performed at a higher specified value of P1, then a third cycle identical to the first cycle is performed. The difference between the volume of the sample on the first measurement and on the third measurement is reported as the volume of fractured cells. It is assumed that cells fracture by exposure to the highest pressure (2nd cycle) so that when the third measurement is made, the measured sample volume has decreased from the first cycle by the amount of the closed cell volume which was fractured.
Cycle fill pressure
[text box]
Enter the fill pressure for the cycles. Typically, the default of 19.500 psig is appropriate for most samples.
End equilibration by:
[group box]

Rate. Equilibration ends when the rate of pressure change drops below the entered amount.

Time. Equilibration ends when the specified time interval is attained.

Number of cycles
[text box]
The number of cycles to be performed. A cycle is a series of functions which equals to a single volume measurement.
Number of purges
[text box]
The number of purges to be performed. A higher number of purges will mean a cleaner sample.
Percent full scale
[text box]
Enabled when Use run precision is selected. Enter the run precision volume tolerance which is expressed as a percent of nominal cell volume (sample capacity).
Purge fill pressure
[text box]

The purge fill pressure (in psig or kPa). For FoamPyc analyses, the typical pressure is 3.5 psig. For analyses on standard samples, the measured volume is more precise if a greater fill pressure is used. The default of 19.500 is appropriate for most standard analyses. Some materials, such as organic polymers, may require a lower pressure in order to limit permeability into the sample matrix.

The default is 500 psig for the High Pressure sample chamber.

Record P1 equilibration data [check box]
Record P2 equilibration data [check box]

Record first. Enter the number of cycles to be recorded at the beginning of the analysis.

Record last. Enter the number of points to be recorded at the end of equilibration.

Use run precision
[check box]
Select to use run precision. This feature provides early termination of the analysis when certain criteria are met. The analysis terminates after five consecutive cycles are within the specified tolerance. Typically, a large number (50 to 99) of cycles is requested. If a small number of runs is selected, the analysis stops when the entered number is reached even though the specified tolerance has not been met. If fewer than five cycles are requested, this feature is disabled.
  For fields and buttons not listed in this table, see Common Fields and Buttons.
 
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