Qualitative Characterization of Granular Materials and Moisture Measurements - Broadband Reflectometry for Enhanced Diagnostics and Monitoring Applications - page 95

0.50

0.45

0.40

0.35

0.30

0.25

0.20

0.15

H L1 500
Regression
Co n fidence lev e l of 95%

0.10

0.05

0.00

0 5 10 15 20 25

ε app

(a)

0.50

0.45

0.40

0.35

0.30

0.25

0.20

0.15

TDR80E04
Regression
Confid e nce level of 95%

0.10

0.05

0.00

0 5 10 15 20 25

ε app

(b)

Fig. 5.2 Global regression curve for sand. a obtained using HL1500. b obtained using
TDR80E04. Related confidence limits, associated to the 95% of probability occurrence, are
also reported

it appears that the distribution of the HL1500 measurement points is narrower than
the TDR80E04 measurement points distribution around their respective extrapolat-
ing polynomial, this is merely due to the fact that upper and lower limits mainly
indicate how well the regression curve fits the experimental points, and should not
be attributed to a better performance of the HL1500.

5.3.3.1 Consideration on Practical Implementation

As expected, TDR80E04 exhibits a better performance in terms of accuracy than its
less-expensive portable counterpart, the HL1500. Nevertheless, the adoption of the