1. Steady state heat transfer method.
2. Unsteady state (transient) heat transfer method [6].
The steady state heat transfer methods often require a long time to complete and moisture migration may introduce significant measurement errors [7]. The transient methods are most suitable for biological materials that are generally heterogeneous and often contain high moisture content, where the line heat source method is one of the most widely used. Here a bare wire method is used as heating source, and estimates the thermal conductivity based on
relationship between the sample core temperature and the heating time. The rate of heat generated in the wire ‘q’ W/m: