Determination of physical, mechanical and thermal properties of barley grains (vars. Nosrat and Kavir)

Barley is an ancient and important cereal grain crop in iran. Complete knowledge of properties of barley grains such as physical¡ mechanical and thermal properties has a decisive importance for the realization of many technological processes¡ especially for monitoring of their qualities and health harmlessness during their production and storage. The aim of this study was to measuring of Physical¡ Mechanical and Thermal Properties of two varieties of persian barely grain¡ Nosrat and Kavir. For this purpose¡ effect of moisture content at four levels of 7.3¡ 12.1¡ 16.8¡ and 21.6% d.b. for Nosrat variety¡ and four levels of 6.7¡ 11.6¡ 15.4¡ and 21.2% d.b. for Kavir variety¡ on some physical properties of barley grain was studied. Effects of moisture content¡ grain orientation¡ and variety on mechanical properties namely¡ rupture force Strain energy density were determined. In addition¡ thermal properties of barley grain varieties such as specific heat¡ thermal conductivity¡ and thermal diffusivity at initial moisture contents of the grains and temperature of 25°C¡ were measured.The results showed that¡ with increasing moisture content¡ length¡ width¡ thickness¡ arithmetic mean diameter¡ geometric mean diameter¡ sphericity¡ surface area¡ thousand grains mass¡ angle of repose¡ and static coefficient of friction on various surfaces¡ for both varieties increased. Bulk density and true density of the two varieties increased as moisture content increased. The effect of moisture content on porosity of the two varieties of barley grain was not significant. With increasing moisture content¡ the rupture force for both varieties decreased¡ while the rupture energy of the varieties increased. In addition¡ rupture force and Strain energy density for both varieties under horizontal orientation was higher than vertical orientation The average value of the rupture force for Nosrat variety was obtained as 104.28 N¡ varying from 53.11 to 172.39 N¡ while the value for Kavir variety was 71.76 N¡ varying from 40.88 to 111.72 N. The mean value of the rupture energy for Nosrat variety was calculated as 54.38 mJ¡ ranging from 29.10 to 78.24 mJ¡ while the value for Kavir variety was 60.65 mJ¡ in the range of 40.33 to 77.43 mJ. There is not any significant difference between the two varieties in the case of thermal properties.