Biomedical Engineering Reference
In-Depth Information
7
6
84.1
5
50.0
15.9
4
3
0.1
1.0
Aerodynamic Diameter ( m m)
10.0
Fig. 4.14 APSD presented using CITDAS software with log-probit (+5) scaling for left-hand
ordinate axis : The linear relationship with this scaling used to estimated GSD by (4.6) is shown on
right-hand ordinate axis
2. Not applicable (NA) is reported for MMAD and GSD if the following situations
occur:
(a) Greater than 50% of the cumulative drug mass is deposited on the lowest
impaction stage (backup filter or MOC (in the case of the NGI—if used)).
(b) Fewer than three stages have a cumulative drug mass >1% of the total mass
collected.
In addition, GSD is calculated after applying a test such that the APSD distribu-
tion is determined to be lognormal within ±1 standard deviations of the MMAD.
CITDAS calculates whether or not to report GSD by performing a linear regression
of the cumulative mass % undersize plot (applying the log-probit scale) between the
probit (+5) values 4 and 6 (Fig. 4.14 ). If the R 2 coefficient for the regression exceeds
the user defined value (default is 0.95), GSD is reported; otherwise, the value for
GSD appears as “NA.”
The “import CSV file” function in CITDAS provides a powerful feature with the
potential to enable this software to link up with other applications, such as EXCEL
(Microsoft Corporation, Redmond, WA, USA). This capability allows files exported
from CITDAS in CSV format to be modified/edited and reimported. Use of this func-
tion with appropriate verification of data integrity streamlines data input into CITDAS,
potentially reducing manual data entry requirements in repetitive situations.
DISTFIT 2008 ® (Chimera Technologies Inc., Forest Lake, MN, USA) is an
alternative software package, and though not specifically tailored for OIP aerosol
measurement applications, has considerable capabilities in being able to handle a
much wider range of particle size, as well as count (number), surface area and
volume (mass) weightings. Its main advantage is the ability to join particle size
distributions from different measurement techniques into a contiguous whole for
subsequent data manipulation. Much of its content is based on the chapter on par-
ticle size statistics in the textbook by Hinds on the topic Aerosol Technology [ 83 ].
Search WWH ::




Custom Search