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Title: SIMULTANEOUS DETERMINATION OF DENSITY AND WATER CONTENT BY MICROWAVE SENSORS

Author
item TRABELSI, SAMIR - OICD
item KRASZEWSKI, ANDRZEJ
item NELSON, STUART

Submitted to: Electronics Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/8/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Because moisture content is the most important characteristic of cereal grains determining suitability for safe storage, and because moisture content is important in determining the price of grain, rapid techniques for testing grain moisture are needed. Electronic grain moisture testers have been developed that utilize the electrical properties of grain, known as dielectric properties. New research on the variation in dielectric properties of grain with the bulk density, or test weight (an important characteristic of grain), has shown that not only moisture content, but also the bulk density of the grain can be determined from the microwave dielectric properties of the grain. This paper reports basic relationships between the dielectric properties of wheat and moisture content, bulk density, temperature, and the microwave frequency at which the dielectric properties are measured. From these fundamental equations, it is possible to determine the moisture content and the bulk density of grain. The new technique offers promise for use in instruments that will be able to sense the moisture content of flowing grain reliably. Current technology fails to accurately sense such moisture well, because density fluctuations produce large errors in moisture determination. Thus, new on-line grain moisture monitoring equipment can be designed that will be helpful in maintaining the quality of grain for domestic use and for the export market.

Technical Abstract: A new approach is proposed for nondestructive, simultaneous determination of density and water content of particulate materials by measuring their dielectric properties at microwave frequencies.