Capacitance sensors for nondestructive moisture determination in grain, nuts and bio-fuel materials

Moisture content of grain, nuts and similar organic materials is an important property to be known to determine their time of harvest, and at various stages of their processing and storage. Several moisture measuring instruments are available in the market but for most of these instruments some sort of sample preparation is needed that involves shelling, grinding and weighing. The samples in this process are usually destroyed, and the measurement involves considerable time and labor. In this work, estimating moisture content (MC) of various types of grain, nuts, and bio-fuel materials from measurement of certain dielectric related properties of a parallel-plate capacitor holding samples of these materials between them at radio frequencies is presented.