Experimental and theoretical study of oxygen diffusion within packed beds of carbon black

The role of membrane ion exchange capacity on membrane|gas diffusion electrode interfaces: a half-fuel cell electrochemical study

“…Using Eq. (6), the effective gas phase diffusion coefficient, D e , is calculated to be $4.9 Â 10 À3 cm 2 s À1 , which is in good agreement with results of Brilhac et al [23]. The second term, D r , represents residual diffusion through micropores, impregnated with Nafion Ò ionomer and liquid electrolyte so that void spaces and macropores are completely flooded.…”

“…where D O 2 ;g is the bulk gas phase diffusion coefficient of O 2 ($0.189 cm 2 s À1 ) and D K the Knudsen diffusion coefficient for diffusion of oxygen in micropores The tortuosity factor, s, is estimated to be $2.1 using the kinetic theory of gas [23]. If the overall process is limited by micropores, then D O 2 ;g is much higher than D K such that…”

Size distribution, chemical composition and oxidation reactivity of particulate matter from gasoline direct injection (GDI) engine fueled with ethanol-gasoline fuel

“…The reaction orders of soot samples and oxygen are given as n and r, which are set unity in this study, because many early studies have found that this kinetic equation is in first order, i.e. the reaction orders are close to unity [26,27]. It was reasoned that in the soot oxidation condition, gases desorption rate is much higher than the adsorption rate, therefore the kinetic equation is in first order [28].…”

Modeling the Cathodic Region in Crevice Corrosion under a Thin Electrolyte Film Including Particulates

“…C b is the bulk concentration of oxygen (based on its solubility which is a function on salinity and temperature), δ is the thickness of the mass transfer boundary layer which can be approximated to be the thickness of the stagnant electrolyte layer (G f ), and D eff is the effective diffusivity of oxygen. For the case of diffusion through a liquid film which contains particulates, the effective diffusivity of oxygen depends on the porosity (1 -φ particles ) and tortuosity (τ) of the particulate layer through which oxygen must diffuse (10). The shape of the particles determines the value of the tortuosity (τ).…”