Physical characteristics of maize grain as influenced by varietal and moisture differences

Abstract

ABSTRACT The objective of the study was to determine the geometric, gravimetric, aerodynamic, and frictional properties of maize grain as affected by varietal differences and moisture content. Honampa, Omankwa, Abontem, Timtim, and Obatanpa were the five maize grain varieties studied. Moisture content, geometric properties, gravimetric properties, aerodynamic properties, and frictional properties were studied. The geometric mean diameters ranged between 6.65 and 7.55 mm, while projected areas ranged between 52.98 and 73.12 m2. The surface area was between 139.69 and 180.29 mm2, and sphericity was from 0.71 to 0.80. The following ranges were obtained as thousand grain weight (213.74 and 292.89 g), and bulk density (709.50 and 746.00 kg/m3). The volume of a single seed was between 1.71 × 10−7 and 2.34 × 10−7 m3 while true density was 1250.0 kg/m3. Porosity ranged from 40.32% to 43.24% and terminal velocity ranged between 2.12 and 2.98 m/s. Drag coefficient of 7.18 to 14.60, drag force of 0.002 to 0.003, and Reynolds number between 992.71 and 1579.20 were similarly obtained. The static angle of repose varied with material surfaces while the dynamic angle of repose varied with grain variety. The grain demonstrated 19° static angle of repose, which portrays a very free flow. All the geometric properties increased with moisture besides sphericity although insignificant. The thousand grain weight, volume of single grain, and porosity increased with moisture content. Nonetheless, bulk density decreased and true density remained the same as moisture content increased. Terminal velocity, Reynolds number, and drag force increased as drag coefficient decreased with moisture content. The frictional properties increased with moisture content, and the Reynolds number was <2100, hence, the linear flow of grain. Geometric, gravimetric, aerodynamic, and frictional properties of maize grain were dependent on both grain variety and moisture content.