Re: Tensiometers: data variability vs TDR

[owner-sowacs@aqua.ccwr.ac.za]

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We were working with compost materials that had large chunks of bark and
used both the TDR and tensiometers. The signal from the TDR could be pretty
wild with a lot of little "wiggles" that made automatic detection of the
end points difficult. You might consider using shorting diodes on both ends
of the wave guides Tensiometers worked fine but the range of tensions we
saw depended more on how the bed was operated then the material. For
example when we ran toluene vapors through the bed microbiological activity
would raise the temperature and the bed would dry in that region. Upon
drying the micro activity fell off. The final result was a drying front
moving through the reactor.
See Gostompski, P.A., J.B. Sisson, and R.S. Cherry. 1997. Water content
dynamics in biofiltration: The role of humidity and microbial heat
generation. J. Air & Waste Mange. Assoc. 47:936-944.