Micromeritics Gemini VII 2390a, Operator'S Manual, Page: 308 / 426

D
avg
K
2
 
Rc
K
Rc
K
1 +
+
 
Rc
K
 
Rc
K
1 +
 
Rc
K
2
Rc
K
1 +
2
+
------------------------------------------------------------------------------------ =
P
avg
K
1 –
2
A
–
1
F
+
 
D
avg
K
 
-------------------------------------
ln =
Tw
avg
K
HP
1
HP
2
P
avg
K
 
ln
------------------------
HP
3
=

Td Tw
avg
K
TW
I
1 +
– =
CSAc
K
Davg
K
2
-----------------

Td
+
2
10
16 –
cm
2
/
A
2
 
=
LP
K
Vc
I
CSAc
K
-----------------
=
D
avg
Knew
D
avg
Kold
2

Td
 
+ =
D
avg
Jnew
D
avg
Jold
2
 
Tw

+ =
Appendix C Gemini VII
C-14 239-42828-01 - Dec 2012
weighted average pore diameter and a corresponding length sufficient to account for
the required volume of adsorbate. The weighted average pore diameter is calculated as
follows:
D
avgK
is the diameter of a pore which would have a surface area that is the average of
the areas for pores radius Rc
K
and Rc
K+1
, if its length was the mean of the lengths at
those radii.
The relative pressure corresponding to D
avgK
is calculated as follows:
The thickness of the adsorbed layer at this pressure is calculated as follows:
The decrease in thickness of the wall layer by desorption from the walls of new pores
during the lower portion of the pressure interval is calculated as follows:
The cross-sectional area of the newly opened pores is calculated as follows:
The length of the newly opened pores is calculated as follows:
c.) Pore diameters and radii are adjusted for the change in thickness of the adsorbed wall layer
during this interval. If new pores were opened during this interval, the average diameter is
adjusted by the change in layer thickness during the second portion of the desorption interval
as follows:
The layer thickness change during the whole interval is added to diameters of previously
opened pores as follows: