Horvath-Kawazoe; Slit Pore Geometry (Original Hk - Micromeritics ASAP 2460 Operator's Manual

Appendix C
where
ΔV =
p
A =
p,i
A , l
p,i,cum i,cum
C =
v
D =
r
=
k
t
=

Horvath-Kawazoe

A relative pressure lower limit is determined such that L-d
than this limit are discarded. For each collected relative pressure point, values of L are chosen in an
iterative manner, and the relative pressure (P/Po) determined by solving one of the following
equations:
• Slit Pore Geometry (original Horvath-Kawazoe)
• Cylinder Pore Geometry (Saito/Foley)
• Sphere Pore Geometry (Cheng/Yang)

Slit Pore Geometry (original HK)

When you use the original Horvath-Kawazoe
of P. The value of L is determined when the solved-for relative pressure is within 0.1% of the collected
absolute pressure.
K
P
------ -
ln ------ - =
RT
Po
where
32
10 =

=
d =
0
where:
D
A
D
s
C-26
Change in pore volume
Pore surface area
Summations over the lengths and areas calculated so far
=
Volume correction factor
Density conversion factor
Average Kelvin radius
Average thickness
9
method, the following equation is solved for each value
32 4
 
IP 10
------------------------ ------------------- -
4 3

L 2d – 3L d –
0 0
4
the number of cm that are equal to Å
gas solid nuclear separation at zero interaction energy (Å),
D + D
A s
------------------- -
2
= molecular diameter (Å) from the Horvath-Kawazoe Physical Proper-
ties window
= diameter of sample atom (Å) from the Horvath-Kawazoe Physical
Properties window
never equals zero. All pressure points less
0
10 4 10
  
------------------- - --------- - --------- -
– – +
9 3
9L d – 3d 9d
0 0
4
ASAP 2460 Operator's Manual
9
0
Z + Z
S A
------------------ -
2
246-42800-01 - Aug 2013