TITLE:
Electromagnetic and Optical Methods for Measurements of Salt Concentration of Water
AUTHORS:
Ø. A. Tengesdal, B. L. Hauge, L. E. Helseth
KEYWORDS:
Salinity, Electromagnetic Sensing, Optical Sensing
JOURNAL NAME:
Journal of Electromagnetic Analysis and Applications,
Vol.6 No.6,
May
27,
2014
ABSTRACT: Sensors
for monitoring the salinity of water are useful tools in both environmental
sciences and chemical engineering. Sensors based on a large variety of
principles have been developed. Here we describe the design and testing of two
different, noninvasive measurement methods for monitoring the salt
concentration of water. The first method is based measurements of the
refractive index using a folded-path optical refractometer, while the second
utilizes an electromagnetic resonator, consisting of a magnetic coil and a
capacitor, which is brought to resonance by an external magnetic field source.
It is demonstrated that the folded-path optical refractometer allows one to
monitor changes in salt concentration down to 1 mM in the range between 0 and
0.7 M, whereas the electromagnetic resonator has the capability of monitoring
concentration changes as small as 0.3 mM over the more limited range between 0
and 5 mM.