Microwave density – independent permittivity functions as soybean seeds’ moisture calibrators: A new approach

Abstract

Priyanka Das, Zeeshan Ahmad, H. N. Singh, Ashutosh Prasad

(University Dept. of Physics, Tilkamanjhi Bhagalpur University, Bhagalpur – 812007, India)

Abstract: The present work makes use of data for real part of microwave complex permittivity as function of moisture content measured at 2.45 GHz and 24℃, as extracted from the literature.  The data were individually converted to those for solid materials using seven independent mixture equations for effective permittivity of random media.  Moisture dependent quadratic models, as developed by the present group, were used to evaluate the dielectric loss factor of soybean seeds.  Using these data, a number of density – independent permittivity functions were evaluated and plotted as a function of moisture content of the samples.  Second and third order polynomial and first order exponential growth type of curve fittings with these data have been tried and their performances are reported.  Coefficients of determination (r²) approaching unity (»0.989 – 0.999) and very small Standard Deviation (SD) up to 3.45×10^–4 for these models possess good acceptability.  The regularity in the nature of these variations revealed the usefulness of these densities – independent permittivity functions as indicators/calibrators of moisture content of soybean seeds.  Keeping in view the fact that moisture content of grains and seeds is an important factor determining quality and affecting the storage, transportation, and milling of grains and seeds, the work has the potentiality of its practical applications.

Keywords: microwave complex permittivity, density-independent permittivity functions, soybean, Dielectric Mixture equations, moisture meters, least–squares fit analysis

Citation: Priyanka Das, Zeeshan Ahmad, H.N.Singh, Ashutosh Prasad.  Microwave density – independent permittivity functions as soybean seeds’ moisture calibrators: A new approach.  Agric Eng Int: CIGR Journal, 2010, 12(3): 107-114.