Global Energy Crisis, Vision 20--2020: Prospects And Challenges For Nigeria

ABSTRACT

This paper deals with the measurement of dielectric properties of some local cereals (com,

beans, rice) in the audio frequency range (0.3- 20KHz) since dielectric properties of various agrofoods and biological materials are finding increasing applications, as fast and new technologies

adapt/adopt these cereals for use in their respective industries and research laboratories.

A Marconi instrument, 0.1% universal impedance bridge together with a specially designed

and constructed coaxial sample holder was used for the required measurements. The properties

measured include the dielectric constant, the dielectric loss factor, the loss tangent {or dissipation

factor) and the dielectric conductivity. The frequency dependence of these properties was explored

in this research. The following characteristics were obtained:

(i) Dielectric constants for the cereals (corn, rice and beans) decreased with increase in

frequency in the audio frequency range.

(ii) Dielectric conductivity increased with increase in frequency in the audio frequency range.

(iii) Dielectric loss factor and loss tangent values for the cereals decreased with increase in

frequency in the audio frequency range.

(iv) The capacitance of the samples decreased with increase in frequency in the audio

frequency range.

These electrical characteristics of the cereals are important for many potential applications viz the

use of electric energy for moisture measurement, grain drying, seed conditioning, stored grain insect control and remote sensing for measurement or process control.