Micromeritics ASAP 2460, Operator'S Manual

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Appendix C ASAP 2460 Operator’s Manual
C-42 246-42800-01 - Aug 2013
dV/dD Pore Volume (cm
3
/g-Å):
MP-Method
With the ( t
i
,Q
i
) data pairs, the Akima semi-spline interpolation method is used to interpolate quantity
adsorbed values based on thickness values that are evenly spaced 0.2 angstrom apart starting at the first
outlier point. Outliers are defined as those points that have the maximum instantaneous slope within an
iteratively shrinking subset of all points. The remaining pore surface area calculation result is the slope
of the line defined by two consecutive interpolated points. The slopes of each pair of consecutive
points from the origin to the last point must be monotonically decreasing and non-negative. With the
interpolated points set the following can be calculated:
Average pore hydraulic radius (Å):
Remaining pore surface area for the
i
th
point (m
2
/g):
where
10
4
= unit conversions
V
mol
= liquid molar volume from the fluid property information
Incremental pore surface area occluded for the
i
th
point (m
2
/g):
Cumulative pore surface area occluded for the
i
th
point (m
2
/g):
dV
dD
i
---------
0.5 W
0
3 N
10
3
nm
3
Å
3 N


E

0
-----------------------------------
 
 
 
 
D
i
2
-----
 
 
3 N 1 +
 
–
10
3
nm
3
Å
3


E

0
--------------------------------



N



D
i
2
-----
 
 
3 N –
– exp

=
R
i
t
i
t
i 1 –
+
2
-------------------
=
S
i
Q
i
Q
i 1 –
–
t
i
t
i 1 –
–
------------------------
V
mol
22414cm
3
STP
------------------------------------ 10
4

=
S
inc i

S
i 1 –
S
i
– =
S
cum
i
S
inc i

S
inc i 1 –


S
inc i

+ + + =