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Title: A NEW DENSITY-INDEPENDENT FUNCTION FOR MICROWAVE MOISTURE CONTENT DETERMINATION IN PARTICULATE MATERIALS

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

Submitted to: Institute of Electrical and Electronics Engineers
Publication Type: Proceedings
Publication Acceptance Date: 5/19/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: The moisture content of grain and other particulate agricultural materials is an extremely important factor in determining how long they can be stored without spoilage. Therefore, the ability to monitor moisture content accurately in flowing grain and other products from harvest through marketing, transportation, and processing would be very useful in maintaining high quality. The electrical or dielectric properties of such products are highly correlated with moisture content, and, therefore, suitable electronic instruments can be used for moisture measurement. However, with granular or particulate materials, fluctuations in the bulk density of such products make reliable moisture measurement very difficult. In research on electronic techniques for sensing moisture content, a new mathematical function has been developed which has a very fundamental physical basis. The development of this function is described in the article, and an application is described for which the use of this new function provides accurate moisture contents for samples of wheat at various moisture contents, temperatures, and bulk densities. The new mathematical function is believed to have wider applicability than previously developed functions, and should provide advantages in accurately monitoring grain moisture content to improve quality of grain and grain products for domestic use and for export.

Technical Abstract: A new density-independent function for moisture content determination from microwave dielectric measurements on particulate materials is proposed. The definition of this function is based on the existence of a simple relationship between the bulk density and the two components of the relative complex permittivity and the principle of energy balance in dielectrics expressed by the loss tangent. Its validity and applicability are shown for a granular material, wheat, over broad ranges of microwave frequencies, temperatures, densities and moisture contents.