In the Amazonian forests of Perú a large variety of native wood species can be found, of which only a few are commercially exploited. Exploitation is focused on high density durable hardwoods for ...flooring applications. After selective logging of a few valuable trees the forests often are considered being “unproductive” because there is no market for most of the remaining trees. Having a long-term sustainable forest management and utilization plan in mind, a continuous extraction of more tree species is desirable. For opening out new markets for lesser-used species a concise knowledge of their physical and mechanical properties is essential. Fifteen lesser-used Peruvian wood species were investigated to characterize their wood/water relations. Density, shrinkage behavior, and sorption characteristics were determined. In addition, the functional relation between electrical resistance and moisture content was determined to provide a sound basis for non-destructive moisture content measurements.
To be able to combine the preservation of wooden objects of cultural
significance with energy efficiency measures it is important to develop
our knowledge of the relation between the rate of change ...of relative
humidity and temperature, moisture content gradients and the resulting
dimensional change of wood. The work presented here introduces and
evaluates a method for monitoring dynamic moisture content gradients,
mainly for research applications. Relative humidity and temperature
were measured by miniature sensors, placed in drilled holes at different
depths in wood samples to monitor the moisture transport. The data was
used to calculate moisture content and the results could hence be compared
with the results from a commercial resistance moisture meter,
monitored at the same depths. The results of the two methods did not
coincide. A Fickian model for moisture diffusion was chosen to verify the
monitored results. It showed poor fit with the commercial resistance
method and a reasonably good fit with the new method using relative
humidity and temperature sensors. We concluded that the new method
provides reliable and consistent data suitable for monitoring moisture
content at different depths under unsteady state conditions, while the
data generated by the resistance method in our set-up was inconsistent
with the model and with our understanding of the moisture transport
process.
A three-part study was conducted to improve the measurement of strength in the High Volume Instrument (HVI) classification system for cotton by adjusting the measured strength for moisture content. ...First, a resistance-type moisture meter was used to develop the HVI strength-moisture relationship and formulate correction equations based on data from 275 cotton samples conditioned at five relative humidity levels. The first model validation was conducted at a U.S. Department of Agriculture, Agricultural Marketing Service (AMS) Office to verify the algorithm on cotton samples that were not used in the model development. The second model validation involved field-testing the approach in an AMS Classing Office to determine if moisture conditioning could be relaxed. The study showed that the resistance moisture meter system allowed HVI strength readings to be corrected with reasonable error on samples that had not been preconditioned to a standard relative humidity.
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