Micromeritics ASAP 2460 - Page 341

ASAP 2460 Operator’s Manual Appendix C
246-42800-01 - Aug 2013 C-17
a.) The thickness of the adsorbed layer at the end of the interval is calculated using the equation
located in Thickness Curve Calculations, page C-44.
For the last pressure interval from the lowest Pr
i
to zero relative pressure, reference the calcu-
lations from the equations in Thickness Curve Calculations, page C-44.
For the first pressure interval, there are no previously opened pores so the volume of liquid
desorbed from walls of previously opened pores is zero (Vd
1
= 0), and the remainder of Step
(a) is skipped.
The change in thickness of the wall layer due to desorption from previously opened pores is
calculated as:
The annular cross-sectional area of the wall layer desorbed is calculated for all previously
opened pores:
The total volume of gas desorbed from walls of previously opened pores is calculated:
for all previously opened pores
where LP
j
= length of previously opened pores as calculated in Step b(2).
Tw Tw
1
Tw
i1+
–=
CSA
j
 Rc
j
Tw+
2
Rc
j
2
–10
16–
cm
2
Å
2
----------



=
Vd
i
LP
j

j

CSAa
j
=