To describe the physical system involving the microwaves’ interaction with the
wood during scanning or heating and drying, integral equations or partial
differential equations (PDE) are used. Usually it is very difficult to obtain
solutions to these mathematical equations that explain the behaviour of the given
physical system. FEM divides a physical system into numbers of discrete
elements or cells, since the complete system may be complex and irregularly
shaped. However, the individual elements or cells could be easy to analyse. The
multiphysics software that is used for generating the FEM models in Papers V,
VI, VII and VIII is a modelling package for the simulation of any physical process
that could be described with PDEs [30]. As there were limitations in the available
computational power, a third dimension was ignored. However, the two
dimensions were chosen along and across the fibres to keep the information of the
internal structure as high as possible in order to solve the present multiphysics
challenge