Diffusion in solids 22 Mathematical models 14 Diffusion 6 diffusion 6 Activation energy 4 Computer simulation 4 Drying 4 Grain (agricultural product) 4 Molecules 4 Point defects 4 Porous materials 4 Rotational diffusion 4 article 4 A. organometallic compounds 2 Adsorption 2 Adsorption equilibrium isotherms 2 Adsorption isotherms 2 Adsorption kinetics 2 Agglomeration 2 Attenuated total reflectance 2 Avrami Erofe'ev model 2 Bond strength (chemical) 2 C. X-ray diffraction 2 C. thermogravimetric analysis (TGA) 2 Channel flow 2 Channel flow cell 2 Charge exchange reactions 2 Charge transfer 2 Clay minerals 2 Composite solids 2