Environmental Engineering Reference
In-Depth Information
Ta b l e 5 . 3
Results for LCR capacitance measurements on pure water and air. The correspond-
ing literature values of static permittivities and the estimated
K
p
value are also reported, with
associated standard uncertainties
material
C
m
ε
s
K
p
,
ICM
(m
−
1
)
(pF)
air
294
.
07
±
2
.
85
1
.
0005
±
0
.
0002
3
.
1
±
0
.
1
water
517
.
13
±
4
.
27
78
.
5
±
0
.
1
Ta b l e 5 . 4
Comparison between static electrical conductivities of electrolyte solutions (at
different σ
0
,
ref
) evaluated through the TLM (σ
0
,
TLM
)andtheICM(σ
0
,
ICM
) methods. The
absolute standard uncertainty (only for the ICM method) is also reported
σ
0
,
TLM
σ
0
,
ICM
(mS m
−
1
)
−
1
)
(
S
1.2
1
.
2
±
0
.
1
12.6
12
.
3
±
0
.
3
23.8
23
.
3
±
0
.
6
35.0
34
.
2
±
0
.
8
.
±
.
45.2
44
3
1
1
56.7
55
.
5
±
1
.
3
68.8
67
.
4
±
1
.
6
89.3
87
.
5
±
2
.
1
105.8
103
.
6
±
2
.
5
longer distances were acquired on all the prepared samples, and the corresponding
electrical conductivity values (
σ
0
,
ICM
) were evaluated.
Table 5.5 and Table 5.6 summarize the results obtained for the
σ
0
,
C
−
S
,
σ
0
,
TLM
,and
σ
0
measurements
(through the C-S, the TLM, and the ICM methods), on sand moistened with de-
ionized water and on sand moistened with salted water, respectively. The obtained
results show an overall good agreement among the values obtained through the three
methods. In particular, considering the sand samples, it is worth noting that the
uncertainty related to the ICM method is always lower than the uncertainty related
to the C-S method: this is particularly evident for higher moisture levels.
It is important to note that the final uncertainty on
ICM
is mostly due
to the uncertainty in the evaluation of the probe constant through the C-S method
and through the ICM method, respectively. In fact, the percentage standard uncer-
tainties are 7.5% and 2.3%, for
K
p
,
C
−
S
and
K
p
,
ICM
, respectively. Conversely, the
contributions of the uncertainty related to the other quantities involved (i.e.,
σ
S
and
σ
0
,
C
−
0
,
ρ
sample
,
ρ
oc
,
σ
0
. In fact,
the maximum values of the percentage standard uncertainty for static reflection co-
efficients, not reported here for the sake of brevity, are in the order of 0.15%.
ρ
sc
) hardly influences the final uncertainty of the calculated value of
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