Perform iteration procedure

Checkbox, to include the iteration procedure for the determination of the threshold shear rate (see Appendix). The iteration procedure is determined following measurement of the syllectogram. During iteration, only one sample is taken per cup revolution to avoid optical disturbances.

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Intermediate disaggregation

Checkbox to disaggregate the blood suspension between successive measurement shear rates. Intermediate disaggregation is recommended and may be favourable as the standard procedure, since potential aggregates will break down during disaggregation, resulting in the same starting point before each back-scatter measurement at a given shear stress.

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Samples per shear rate

Number of back-scatter-intensity measurements to perform at each shear stress. Each individual sample is taken once per revolution, at the home position. The program records both the mean back-scatter and its standard deviation.

[2, 200]

Maximum deviation (au)

When a new shear rate is adjusted, the aggregation state of the suspension will gradually become stable. The program checks the absolute error between N successive data points and keeps on sampling until the absolute error is smaller than the value entered here or until an iteration-timeout occurs.

[0.1, 0.5] au

Iteration timeout (s)

When the aggregation signal does not get stable within the time entered here, the measurement is aborted and an error message appears.

[10, 3600] s

Binary search steps

A binary search algorithm is used to automatically generate two more shear rates to fine-tune the rough procedure (which used shear rates obtained from the user defined "iterate.txt" file). Each binary search step results in two more shear rates to measure the back-scatter intensity. They are chosen centered between the current optimum shear rate and next higher and lower shear rates. See also Appendix.

[0, 100]

Sort results

Checkbox, to sort the results: The lowest shear rate first and the highest shear rate last (default). By not sorting the measurement points, and if intermediate disaggregation is not enabled, it is possible to study memory effects (hysteresis) of RBC aggregation vs. shear rate.

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Iteration shear rates

Presets values to which the iteration procedure is performed. Default values are applicable for human RBC’s.

Press <Edit> to change the values.

[1, 7745] 1/s