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ARS Home » Research » Publications at this Location » Publication #76587
Title: MOISTURE CONTENT DETERMINATION IN GRAIN BY MEASURING MICROWAVE PARAMETERS

Author
item Kraszewski, Andrzej
item TRABELSI, SAMIR - OICD
item Nelson, Stuart

Submitted to: Measurement Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Reliable knowledge of the moisture content of grain is very important, because if the moisture content is too high, the grain will spoil in storage or during transit. Moisture content is also important in determining the selling price, because if grain must be dried before storage, the costs of drying must be taken into account. Also, for milling gand other processing, grain moisture content must be adjusted to certain levels. Standard methods for moisture content determination require many hours of drying in an oven, and they are much too slow to be useful in trade or in processing applications. Therefore electronic methods have been developed that sense moisture in grain through the electrical properties of the grain. These electronic methods require corrections for grain temperature and for variations in bulk density, or packing, of the grain. Therefore, they have not been suitable for use in monitoring moisture content in flowing grain. New studies on microwave measurements of grain have shown that moisture content can be determined independent of such bulk density fluctuations and that readings can also be compensated for temperature variation. Thus, instruments can be developed for on-line grain moisture measurements by using these principles. Such equipment will be helpful in maintaining grain quality for domestic uses and for the export market.

Technical Abstract: A concept of moisture content determination from the measurement of the attenuation and phase shift of an electromagnetic wave transmitted through a layer of wet material is explored in the paper. Experimental results for wheat of 10% to 19% moisture content (wet basis) at temperatures from -1 deg C to 42 deg C at the frequency of 16.8 GHZ are used to illustrate the procedure which provides a density-independent and temperature-compensated moisture content determination.