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United States Department of Agriculture

Agricultural Research Service

Research Project: SENSING METHODS & INSTRUMENTATION FOR RAPID DETERMINATION OF MOISTURE CONTENT... AND OTHER QUALITY ATTRIBUTES OF GRAINS, SEEDS, & NUTS

Location: Quality and Safety Assessment Research Unit

Title: The evolution of dielectric properties measurement techniques for agricultural products

Authors
item Nelson, Stuart -
item Trabelsi, Samir

Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: June 3, 2013
Publication Date: N/A

Interpretive Summary: Dielectric properties of materials are electrical properties that determine how materials interact with electric fields such as those of high-frequency and microwave electromagnetic energy. Therefore, the dielectric properties of materials determine how rapidly they will heat in microwave ovens and lower radio-frequency dielectric heating equipment. Dielectric properties are also important in low power applications, such as the rapid measurement of moisture content in grain and other commodities. Therefore it is often important to measure the dielectric properties of materials at the frequencies of interest in any application. In this article, the evolution of dielectric properties measurement techniques for agricultural products is presented. Principles used in measuring the dielectric properties of different agricultural products at frequencies ranging from audio frequencies through radio frequencies and well into the microwave range are briefly described, and references are cited for more detailed information on those techniques. Citations are provided where the dielectric properties of grain and seed, fruits and vegetables, insects, food materials, coal, minerals, limestone and other materials are presented. The information is of interest to engineers and scientists in developing instruments that can provide important tools for improving agricultural production, product processing, product quality preservation, and marketing for the benefit of growers, processors and consumers.

Technical Abstract: The important applications for dielectric properties, or electric permittivities, of agricultural products are described and the evolution of techniques used for their measurement over frequencies ranging from audio to microwave ranges are described briefly. References are cited for further information on the techniques and resulting data reported for grain, seed, fruits, vegetables, and other products.

Last Modified: 9/22/2014
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