Electrical insulation was considered for the external walls of the RF cavity. The initial temperature of all domains in the system, including the air, plastic container, peanuts, upper and bottom electrodes was set at room temperature (20 C). The convective heat transfer boundary conditions were assigned at the outer sample surfaces exposed to air with heat transfer coefficient of h ¼ 20 W m2 K1. The measured dielectric properties of peanuts were entered into the Joule heating module to solve the coupled quasi-static electromagnetic and heat transfer equations. All computer simulations were performed on a Dell workstation with an Intel® Core™ i5-2400, 3.10-GHz processor and 8 GB RAM running a Windows 8.1 64-bit operating system. The direct linear system solver (UMFPACK) was used with a relative
tolerance and absolute tolerance of 0.01 and 0.001, respectively, with the initial and maximum time steps of 0.001 s and
0.1 s. The simulated sample temperature was further used to confirm the experimental data