Engineering properties of luffa (L. cylindrica) seed relevant to the processing machineries

Abstract

Some physical and mechanical properties of Luffa (L. cylindrica) seeds were investigated at five different moisture content levels of 6%, 12%, 18%, 24% and 30%.  The physical properties which included geometric mean diameters (minor, major, intermediate), sphericity, weight, bulk density and coefficient of static friction were determined.  The mean values of the physical properties of the seeds were determined as major diameter 1.1423-1.2427 cm, width 0.54-0.6743 cm, thickness 0.8633-1.079 cm, geometric mean diameter 0.8102-0.9663 cm, sphericity 0.7104-0.7703, surface area 2.0620-2.9512 cm², specific gravity 0.7600-1.0267, bulk density 0.3730-0.6053 g m^-3, and porosity 0.5823-0.0430, respectively.  The physical properties of the seed showed that the moisture content increased but the porosity decreased.  The friction coefficient was measured and was between 0.3263-0.4160 on glass, 0.4265-0.5357 on aluminium and 0.4257-0.6197 on wood.  The mechanical properties, which include fracture force, compressive strength, deformation, tensile strength and strain, all decreased as follows: moisture contents: 6%-30%, fracture force: 1479 N-1208 N, compressive strength: 288-220 N mm^-2, deformation: 5.23-3.86 mm, strength: 3.82-3.09 MPa, and strain: 3.25-2.7.  The results will provide the relevant data of efficient process handling and equipment design of the seeds to the engineers and designers.