Micromeritics ASAP 2460, Operator'S Manual

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ASAP 2460 Operator’s Manual Appendix C
246-42800-01 - Aug 2013 C-25
Dollimore-Heal Adsorption
The calculations for the Dollimore-Heal reports are the same as those for BJH, except for the calcula-
tion of average pore diameter and pore length.
Pore Diameter
Pore diameter is determined from the Kelvin radius and thickness equation:
The average pore diameter is the arithmetic mean of the diameters that bound the interval.
Pore Length
D
i
2 r
k
P
i
 
t P
i
 
+ =
D
i
D
i
D
i 1 +
+
2
-------------------------
 
 
=
l
i
A
p i

10 +

D
i
----------------------
8
=
A
p i

4 10
8
V
p
   
D
i
--------------------------------
=
V
p

C

D

Q
i 1 –

Q
i

– t 10
8

A
p cum


2

t l
i cum


–

– =
C

D
i
2 r
k
t P
i
 
+

t P
i 1 +
  
–
-------------------------------------------------------------
 
 
2
=
t
D
i
2 r
k
–
-------------
=
r
k
r
k i

r
k i 1 +

+
 
2
----------------------------------
=