Experimental study on combined infrared and microwave drying of porous media with particular application in wood industry

Porous materials such as wood have microscopic capillaries and pores which cause a mixture of transfer mechanisms to occur simultaneously when subjected to heating. Infrared and microwave heating of wood products has not been used to a larger extent by the wood industries and manufactures. This could be explained by the insufficient knowledge of the complex interaction between a porous material and process parameters during drying. This article uses the drying experiments to study the effects of drying modes, density and moisture content on wood hardness. Brinell hardness is measured on wood surfaces of Guilan spruce at two angles to the grain.