Micromeritics Gemini VII 2390a, Operator'S Manual

Page: 302 / 426

Appendix C Gemini VII
C-8 239-42828-01 - Dec 2012
t-Plot
t
I
HP
1
HP
2
P
rel
I
 
ln
--------------------- 
HP
3
=
For each point designated for t-Plot
4
calculations, the following calculations are done:
Thickness for the I
th
point (Å):
(Halsey
5
)
t
I
HJP
1
HJP
2
P
rel
I
 
log –
--------------------------------------------
HJP
3
=
or
(Harkins and Jura
6
)
t
I
STSA
1
P
rel
1
 
2
STSA
2
P
rel
1
 
STSA
3 + + =
or
where:
t
I
= thickness for I
th
point
HP1 = Halsey parameter #1
HP2 = Halsey parameter #2
HP3 = Halsey parameter #3
HJP1 = Harkins and Jura parameter #1
HJP2 = Harkins and Jura parameter #2
HJP3 = Harkins and Jura parameter #3
STSA1 = statistical thickness surface area parameter #1
STSA2 = statistical thickness surface area parameter #2
STSA3 = statistical thickness surface area parameter #3
P
rel
I
= relative pressure for the Ith point (mmHg)

A least-squares analysis fit is performed on the (t
I
, N
ads
I
) data pairs where t
I
is the independent variable
and Nads
I
is the dependent variable. Only the values of t
I
between t
MIN
and t
MAX
, the minimum and
maximum thickness, are used. The following are calculated:
a.) Slope (S cm
3
/g-Å STP)
b.) Y-intercept (Y
INT
cm
3
/g STP)
c.) Error of the slope (S
ERR
cm
3
/g-Å STP)
d.) Error of the Y-intercept (YI
ERR
cm
3
/g STP)
e.) Correlation coefficient