Biomedical Engineering Reference
In-Depth Information
Fig. 8.41
Process diagram
for establishing comparable
acceptance limits for
LPM
/
SPM
ratio and grouped
stages for a common range of
acceptable
MMAD
values
Fig. 8.42
Stage group 2 mass deposition data as a function of
MMAD
; the
dashed lines
represent
the prediction interval limits with the circles defining the upper and. lower limits for
MMAD
, each
defined by the intersection between the appropriate prediction interval limit and the corresponding
acceptance limit for group 2
The averages of group 2 and group 4 limits were therefore subsequently used as a
common range of acceptable values of
MMAD
for assessment of the two approaches.
It was found necessary to expand the range of the data using simulation tech-
niques that maintained the characteristics of the original CI data. This procedure
was undertaken in order to determine suitably robust estimates of the performance
of the two approaches at the limits of the established
MMAD
range, which
corresponded to the limits of the observed data. For each set of CI data, a cumulative
mass-weighted APSD curve was generated using a 4-parameter curve fit (Fig.
8.39
).
To shift the curve and thereby shift the
MMAD
, by some delta amount, predicted
values were calculated at delta distance from each of the CI stage
d
50
sizes.
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