Micromeritics ASAP 2020 Confirm Operator's Manual page 368

ASAP 2020 Confirm
The annular cross-sectional area of the wall layer desorbed is calculated for all pre-
viously opened pores:
CSA
The total volume of gas desorbed from walls of previously opened pores is
calculated:
Vd
I
where LP
b. The physical processes occurring for this pressure interval are determined as follows:
(1) If Vd
(2) If Vd
C-16
2
 Rc   Tw 
= + –
J j
   CSAa  
= Lp for all previously opened pores
J J
= length of previously opened pores as calculated in Step b(2).
J
is greater than the current increment of volume desorbed (Vl
I
desorption from walls only is occurring. Total surface of walls exposed thus far
(cm 2 /g) is calculated as follows:

 LP   D 
SA =
W J avg
where
D = weighted average pore diameter calculated below in Step b(2).
avgJ
A new layer thickness (Tw) that will not overcompensate for the actual volume
desorbed in this interval is calculated:
  10 
V1 – V1
I I + 1
Tw
--------------------------------------------------------------
=
SAw
Since no cores are evaporated in this pressure interval, no new pores are revealed.
Thus no ending Kelvin radius and average pore diameter are calculated for this
interval. Note that this means the report may have fewer tabulated intervals on
the collected data report than experimental pressure intervals.
is less than the volume increment desorbed during this interval, the
I
remaining volume is due to new pores with core evaporation taking place in this
interval. K, the number of intervals with new pores exposed, is increased by 1.
(For the interval from the lowest to zero relative pressure, no new pore volume is
calculated and the rest of Step b is skipped.)
The volume desorbed from newly opened pores in this interval is calculated as
follows:
  Vd
Vc = VI – VI –
I I I + 1
2 – 16 2 2
 10  
Rc cm /A
j
8 –
 10  
cm/A for all previously opened pores
J
8

A/cm
I
I
Appendix C
- Vl ),
I I+1
202-42811-01 - Mar 2011