Determining dimensional, gravimetrical and frictional properties of red radish seeds (Raphanus Sativus L.) as a function of moisture content

Abstract

To design the planting, separating, threshing, sizing and packing machines for agricultural products, physical and mechanical properties of the products should be known. In this paper, some physical properties of red radish seeds were studied. Dimensional parameters, when moisture content equals to 5.65% based on dry bases (d.b), were measured using image processing technique. Effects of moisture content on gravimetrical and frictional properties of the seeds, including mass of single seed, 1000-unit seed, bulk density, true density, porosity, static coefficient of friction on various surfaces, and angle of repose based on pouring, Hele-Shaw, empting and filling methods were studied. Effects of volume of the container (150, 350, 550 and 750 mL) and height of fall on bulk density and porosity of the radish seeds when moisture content equals to 5.65% (d.b) were studied. Also length, width, thickness and mass distributions of radish seeds were modeled using Gamma, Generalized Extreme Value and Weibull distributions. Results showed that length, width and thickness of the seeds ranged from 0.660 to 0.900 mm, 0.524 to 0.763 mm and 0.490 to 0.759 mm, respectively. With increasing volume of the container from 150 to 550 mL, bulk density of the seeds increased; but with increasing volume of the container from 550 to 750 mL, bulk density of the seeds decreased. With increasing volume of the container from 150 to 550 mL, bulk density of the seeds increased; but with increasing volume of the container from 550 to 750 mL, bulk density of the seeds decreased. With increasing moisture content from 5.65 to 21.71% (d.b) , bulk and true density of the seeds decreased from 694.807 to 654.889 kg/m3 and 1141.810 to 1057.795 kg/m3; but with increasing moisture content from 5.65% to 21.71% (d.b) , 1000-unit mass increased from 6.98 to 7.17 g.