diffusion in an through solids

absorption activated diffusion activation energy adsorbed alloy analcite anionic atoms Barrer 28 C₁ C₂ caesium cal./atom cal./mol calculated capillary carbon cations cellulose Chap Chem concentration gradient conductivity copper crystal crystalline crystallites curve denotes diffusion constant diffusion equation diffusion process diffusion systems electrons energy of activation equation equilibrium films function Fused silica gas flow gases give given grain boundaries H₂ halide halogen heat helium heulandite hydrogen increases interpolymer interstitial ionic ions kinetic lattice layer meability measure membrane mercury metal method mobility molecular molecules observed obtained oxide oxygen palladium permeability constants permeation rate permeation velocity phase Phys plane plate Poiseuille flow polymer pore potassium potassium hydride pressure pyrex ratio rubber silica glass silver Smithells sodium solid solubility solution sorbed sorption surface Table Temp temperature coefficient theory thickness thorium tube tungsten values vapour zeolites дх