Similar to LaCoO4.14, La2-xSrxCuO4±δ shows oxygen diffusion at moderate temperatures. The Oxygen Isotope Back Exchange (OIBE) experiments are done in order to investigate the effect of strontium on the oxygen diffusion in as grown single crystals of La2-xSrxCuO4±δ (x =0, 0.05, 0.1, 0.15). Neutron diffraction data collected at TriCS@SINQ are in agreement with diffusion measurements achieved by o...

Surface exchange and oxygen vacancy diffusion dynamics were studied in double-perovskites LnBaCo2O5.5+δ (LnBCO) single-crystalline thin films (Ln = Er, Pr; -0.5 < δ < 0.5) by carefully monitoring the resistance changes under a switching flow of oxidizing gas (O2) and reducing gas (H2) in the temperature range of 250 ~ 800 °C. A giant resistance change ΔR by three to four orders of magnitude in ...

Grain boundary mobility of CeO, containing 0.1% and 1.0% trivalent dopant cations (Sc, Yb, Y, Gd, and La, in order of increasing ionic radius) has been measured. At the lower dopant concentration (intrinsic regime), mobility is controlled by grain boundary diffusion of host cations, whereas at the higher dopant concentration (extrinsic regime), mobility is controlled by solute drag through the ...

An isolated, saline-perfused trout head preparation, irrigated with hyperoxic water (PWQ2 = 250 Torr), was used to assess diffusion/perfusion limitations to gill oxygen transfer. In the absence of catecholamines, increasing the perfusion flow rate caused a reduction of the partial pressure of oxygen in the dorsal aortic perfusate, indicating diffusion limitations to oxygen uptake. Physiological...

Renal arterial-to-venous (AV) oxygen shunting limits oxygen delivery to renal tissue. To better understand how oxygen in arterial blood can bypass renal tissue, we quantified the radial geometry of AV pairs and how it differs according to arterial diameter and anatomic location. We then estimated diffusion of oxygen in the vicinity of arteries of typical geometry using a computational model. Th...

Polymer electrolyte fuel cells (PEFCs) are a promising technology for environmentally friendly automobiles, among other applications. However, performance losses due to oxygen transport hindrances in the PEFC’s cathode continue to be an issue in widespread commercialization. This dissertation focuses on the transport of oxygen through the thickness of the PEFC cathode, and the effect of the cat...

Light-mediated chloroplast movements are common in plants. When leaves of Alocasia brisbanensis (F.M. Bailey) Domin are exposed to dim light, mesophyll chloroplasts spread along the periclinal walls normal to the light, maximizing absorbance. Under high light, the chloroplasts move to anticlinal walls. It has been proposed that movement to the high-light position shortens the diffusion path for...

the catalytic oxidation of toluene to benzoic acid in the liquid phase has been studied in an un-stirred tank reactor. low concentration of acetic acid was added in order to increase the solubility of the catalyst in toluene. the dependence of the rate of reaction on the concentration of toluene catalyst and oxygen pressure was studied. it has been suggested that liquid phase oxidation of tolue...

An important but poorly understood factor that affects diffusion rates is the role of speciation during diffusion of a multi-species component. The diffusion of such a component is complicated by the different diffusion coefficient of each species and the interconversion reactions among the species. These complexities can be treated by a diffusion equation that incorporates the diffusive flux...