DETERMINATION OF PHYSICAL AND ENGINEERING PROPERTIES OF TIGER NUT (Cyperus esculentus) RELEVANT TO ITS MECHANIZATION
The physical and engineering properties of fresh and dried tiger nut (Cyperus esculentus) were determined at moisture content of 41.20% and 16.40% on wet basis respectively. The mean values for the three principal axes (length, width and thickness) were 9.52mm, 8.16mm, and 8.16mm for fresh tiger nut and 9.14mm, 7.72mm and 8.03mm for dried tiger nut respectively, showing a decrease with decrease in moisture content and was significantly different at p?0.05. The mean values of the bulk density, true density and porosity of both fresh and dried tiger nut were 0.59g/cm3 , 0.97g/cm3 , 40.61 and 0.58g/cm3, 0.94g/cm3 , 40.35 respectively and were not significantly different at p?0.05. The mean angle of repose and coefficient of static friction over formica, stainless steel, glass and plywood surfaces of fresh tiger nut were 50.11o , 2.73, 2.45, 2.22 and 1.77 while that of dried tiger nut were 48.23o , 2.41, 2.03, 2.11 and 2.00 respectively. The mean rupture force increased with compression force of 90.08N on the major axis to 116.88N for fresh tiger nut and from 120.55N to 161.10N for dried tiger nut and were significantly different at p?0.05. These properties determined are necessary in the design and fabrication of hoppers, conveyor equipment and the force tiger nut can withstand before it is ruptured.