Some Physical Properties of Hemp Seed

Various physical properties of hemp seed were determined as a function of moisture content. As the moisture content increased from 8·62 to 20·88% dry basis (d.b.), the dimensions of the major, medium and minor axes varied from 3·79 to 4·11 mm, 2·92 to 3·11 mm and 2·47 to 2·82 mm, respectively. In the same moisture range, studies on rewetted hemp seed showed that the sphericity, surface area and thousand seed mass increased from 0·795 to 0·808, 9·4 to 10·3 mm2 and 15·3 to 16·9 g, respectively. As the moisture content increased from 8·62 to 20·88% d.b., the bulk density, true density and porosity were found to decrease from 557·5 to 512·3 kg m−3, 1043·0 to 894·8 kg m−3 and 46·5 to 42·7%, whereas angle of repose and terminal velocity were found to increase from 24·6 to 27·7° and 5·5 to 6·4 m s−1, respectively. The static and dynamic coefficients of friction on various surfaces, namely, rubber, plywood and galvanised metal also increased linearly with increase in moisture content. The rubber surface offered the maximum friction followed by plywood and galvanised metal in descending order.