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    Author(s): Peter R. Robichaud; Roger D. Hungerford; David S. Gasvoda
    Date: 1999
    Source: U.S. Patent 5,920,195. July 6. Arlington, VA : U.S. Patent and Trademark Office. 9 p
    Publication Series: Miscellaneous Publication
    PDF: View PDF  (1.5 MB)


    An apparatus and method for the moisture content measurement of compressible materials using pressure to firmly hold surface probes against the marerial to be measured. The apparatus uses moisture measurement circuitry employed in frequency domain impedance or time domain reflectometry devices to obtain moisture content readings from materials. These moisture content readings are based on the apparent dielectric constant of the measured material. Subsurface air voids or gaps found in loose layered materials undesirably influence moisture measurement readings by reducing the apparent die1ectric constant of the measured material. Pressure is supplied through the apparatus to the material in the proximity of the surface probes, thereby reducing air voids to enhance measurement accuracy. The apparatus and method are especially useful for compressible organic materials such as forest duff, hay and soil.

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    Robichaud, Peter R.; Hungerford, Roger D.; Gasvoda, David S. 1999. Apparatus and method for the measurement of forest duff moisture content. U.S. Patent 5,920,195. July 6. Arlington, VA : U.S. Patent and Trademark Office. 9 p


    duff moisture content, forest litter, measurement, apparatus, probes

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