Some physical properties of rough rice (Oryza Sativa L.) grain

Designing the equipment for processing, sorting, sizing and other post-harvesting equipment of agricultural products requires information about their physical properties. In this study, various physical properties of rough rice cultivars were determined at a moisture content of 10% (wet basis). In the case of Sorkheh cultivar, the average thousand grain weight, equivalent diameter, surface area, volume, sphericity, aspect ratio, true density, bulk density and porosity were 21.64 g, 3.35 mm, 31.76 mm2, 20.27 mm3, 39.71%, 0.28, 1269.1 kg/m3, 544.34 kg/m3, and 56.98%, respectively. The corresponding values were 20.52 g, 3.4 mm, 32.58 mm2, 21.06 mm3, 39.88%, 0.29, 1193.38 kg/m3, 471.21 kg/m3, and 60.37% for Sazandegi cultivar. For Sorkheh cultivar, the average static coefficient of friction varied from 0.2899 on glass to 0.4349 on plywood, while for Sazandegi cultivar the corresponding value varied from 0.2186 to 0.4279 on the same surfaces. Angle of repose values for Sorkheh and Sazandegi cultivars were 37.66° and 35.83°, respectively. Linear model for describing the mass of rough rice grain was investigated. Mass was estimated with single variable of kernel length with a determination coefficient as 0.862 for Sorkheh cultivar whereas for Sazandegi cultivar was as 0.860.