NONDESTRUCTIVE MICROWAVE CHARACTERIZATION FOR DETERMINING THE BULK-DENSITY AND MOISTURE-CONTENT OF SHELLED CORN

A method based on nondestructive microwave characterization is used fo r simultaneous determination of the bulk density and moisture content of shelled corn. This method can be applied regardless of the measurem ent technique and thus considerably simplifies the calibration procedu re. Calibration equations, both for the bulk density and for the moist ure content, are given, together with the standard error of performanc e (SEP) at several frequencies in the range 11-18 GHz and three temper atures, 14, 24 and 34 degrees C. The bulk density, ranging from 695 to 830 kg m(-3), can be determined with SEP in the range 11-15 kg m(-3) Neither the sample moisture content nor its temperature are required i n order to determine the bulk density. The moisture content ranging fr om 9% to 19% on a wet basis, can be determined at each temperature wit hout knowledge of the bulk density with SEP of less than 0.5% moisture content. Results of an error analysis of the measurements show that a bout half of the total uncertainties in bulk density and moisture cont ent can be considered systematic errors and thus they are correctable.