Micromeritics ASAP 2460, Operator'S Manual

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ASAP 2460 Operator’s Manual Appendix C
246-42800-01 - Aug 2013 C-7
Thermal Transpiration Correction
During data reduction, thermal transpiration correction is applied to the data if the user selected
Apply
thermal transpiration correction
from the
Report Options
window. Starting with the first collected
pressure, the following calculations are performed until the pressure ratio (PC/P) is greater than or
equal to 0.99.
where:

= Weber’s coefficient, 0.033

= Weber’s coefficient, 0.245
F , Y ,

= intermediate values for subsequent calculations
G = Weber’s coefficient, 2.5
H = Weber’s coefficient, 2
MD = thermal transpiration hard sphere diameter of gas (Å), from the
Adsorptive
Properties
window
P = equilibrated collected pressure measured by gauge at temp T
amb
SD = inside diameter of sample tube (mm), from the
Report Options
window
T = average temperature
T
amb
= room temperature (298 K)
T
bath
= analysis bath temperature ( K ), from the
Po and Temperature Options
window
Y
P SD MD
2
 
2.33 T

------------------------------------
 
 
10
3
=

1

G

Y +
1

H

Y +
-----------------------
=
F
1

Y
2

Y

+ +
---------------------------------
=
P 1 F 1
T
bath
T
amb
------------



–



–
 
 
 
=
T
bath
T +
2
--------------------