Thermal conductivity is one of the most important properties for engineering applications. In order to find out the conductivity of poor conductors, the material under investigation cannot be used in the form of a long bar just like the good conductors as the heat loss from the sides would be considerably high with respect to the heat actually conducted through the substance itself. In this regard, to determine the thermal conductivity of the poor conductors, specimens in the form of a disc were studied and conductivity was measured by applying Newton's law of cooling. Thermal conductivity also depends on the anisotropic property of the material which indicates the observation of different values along different axes of same material. This work deals with the determination of thermal conductivity of different wooden specimens and reinforced composites made of jute fiber and chopped stranded mat of glass fiber by self-constructed Lee's disc apparatus with compact electrical circuit instead of conventional steam chamber. For porosity in timber, the thermal conductivity of wooden specimens is low. Moreover, due to the aforementioned anisotropic property, the thermal conductivities of the wooden samples, both parallel and perpendicular to the grain were tested. It reflects that the thermal conductivities along the direction of the grain were greater than perpendicular to the grain. Validation of the experimental data from the self-constructed apparatus was done by comparing the data achieved at Bangladesh Council of Scientific and Industrial Research which are in very good agreement. Afterwards, experiments for measuring thermal conductivity for jute fibre reinforced composites for six different ply configurations were carried out. It was observed that the thermal conductivities of hybrid composites i.e. those which consist plies of chopped strand mat of glass fibres were significantly less than those of the composites made of pure bi-directional jute mat.
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