Physical, mechanical and aerodynamic properties of Acorn (Quercus suber L.) as potentials for development of processing machines

This study determined a number of physical, mechanical and aerodynamic attributes of acorn nuts grown in Iran at a moisture content of 5.84% dry basis (d.b). The mean of major diameter, intermediate diameter, minor diameter and geometric mean diameter were 31.27, 18.20, 16.64 and 21.89mm, respectively. Mean values for sphericity and surface area were 68.29% and 1462.73 mm(2), respectively. The true density, bulk density and porosity were 1028.33 kgm(-3), 512.62 kgm(-3) and 49.84%, respectively. Cracking forces with loading on the lateral axis, vertical axis and thickness of the nuts were determined to be 367.84, 480.53 and 401.19N, respectively. Static friction coefficient on plywood, galvanized steel sheet and fiberglass were 0.38, 0.33 and 0.27, respectively, while the dynamic angle of repose on plywood, galvanized steel sheet and fiberglass were 25.53 degrees, 21.74 degrees and 16.31 degrees, respectively. The terminal velocity for the nut, kernel and hull were 19.52, 16.80 and 4.07 ms(-1), respectively. These findings provide useful data for the suitable design and development of crop-processing machines such as sorting, grading, grinding, drying and extraction equipments.