Oxygen exchange coefficient

FIGURE 3.4 Measured effective surface oxygen exchange coefficient of the LSM/YSZ composites as a function of the LSM content. (From Ji, Y. et al., Solid State Ionics, 176 937-943, 2005. With permission.)... 

In the first place our understanding of factors that control and limit the interfacial kinetics is still rudimentary, and therefore should be a fruitful area for further investigation. The apparent correlation between the surface oxygen exchange coefficient and the tracer diffusion coefficient D for different classes of oxides, the fluorite-related and the perovskite-related oxides, as noted by Kilner et al. [73], clearly indicate the potential of isotopic exchange. 

Oxygen Diffusion Coefficient (D ), Oxygen Surface Exchange Coefficient (Ar), and Oxygen Ionic Conductivity (tr,) of LaMn03-Based Oxides Measured by SIMS Technique... 

Isotopic exchange reaction rates and oxygen diffusion coefficients of Pt/M-CZ, S-CZ and R-CZ at 41 are listed in Table V (Dong et al., 2004a). The surface diffusion rate for R-CZ (Rg) is nearly 4 times larger than the bulk diffusion rate or the equilibrium isotopic exchange rate (R ), while it is... 

Fig. 9. Rate coefficients for reactions of protonated ethyl acetate. The open circles represent data for hydrolysis. Closed circles are for the oxygen-exchange reaction of the carbonyl- 80 labelled...

Kremer, J.N., Reischauer, A., and D Avanzo, C. (2003a) Estuary-specific variation in the air-water gas exchange coefficient for oxygen. Estuaries 26, 829-836. 

The reduction of oxygen to takes place at the interface of the three phase boundary. The mixed cathode which allows both electron and to travel along the surface and bulk extends the interface of the three phase boundary to an active zone for the reduction of O2 to 0 . The extension of the active zone depends on the oxygen diffusion, surface exchange coefficient, the microstructure and porosity of the cathode layer, shown in Fig. 2 (a). ... 

In the absence of tracer data, estimates of gas exchange coefficients in streams can be made from a number of empirical equations, which typically depend on a combination of the stream mean velocity and depth (V and d, respectively). Some equations contain other parameters, such as shear velocity, width, and Froude number (u, w, and N, respectively) of the stream. The Froude number is equal to (V/ fgd), and is the ratio of stream velocity to the travel speed of a shallow-water surface wave. By convention, the empirical equations given for streams are usually for a reaeration coefficient, which is the gas exchange coefficient for oxygen divided by the average stream depth. Examples of empirical equations for reaeration coefficients are shown in Table 2-5. 

---