Oxygen is one of the most important factors determining the aging potential of bottled wine, and oxygen diffusion into bottled wine is extremely dependent on the sealing effectiveness of the closure. A nondestructive colorimetric method was developed to measure oxygen diffusion from 1 to 9.8 mg/L during the postbottling period. This method was used to study oxygen diffusion through different cl...

This paper deals with the facilitated diffusion of oxygen in systems containing proteins, such as ferrohemoglobin, that combine reversibly with oxygen. The phenomenon is treated in terms of translational diffusion of free and bound oxygen molecules, and of the reaction rate of the oxygen molecules with the oxygen-binding protein. These considerations lead to a differential equation (see Equatio...

Perovskites are known as mixed electric conductors because they show both electronic (via electron holes) and ionic (via oxygen vacancies) conductivity. Since the electron conductivity is orders of magnitude higher than the ionic one, oxygen vacancy bulk diffusion is regarded as the rate limiting step in oxygen permeation through perovskites. However, for thin perovskite layer the rate of this ...

How impurity atoms move through a crystal is a fundamental and recurrent question in materials. The previous models of oxygen diffusion in titanium relied on interstitial lattice sites that were recently found to be unstable--leaving no consistent picture of the diffusion pathways. Using first-principles quantum-mechanical methods, we find three oxygen interstitial sites in titanium, and quanti...

Hemoglobin in solution augments the rate of steady state diffusion of oxygen. The flux of oxygen exceeds the diffusive flux by an amount, the facilitated flux, which is constant for a given hemoglobin concentration and is invariant with changing oxygen tension. The facilitated flux is inversely proportional to the length of the diffusion path. Facilitation decreases with increasing molecular si...

Dissolved water is known to dramatically enhance oxygen diffusion in silicate melts, glasses and minerals. A quantitative theory has been developed to explain this phenomenon by transport via molecular H2O diffusion [Y. Zhang, E.M. Stolper, G.J. Wasserburg, Diffusion of a multi-species component and its role in the diffusion of water and oxygen in silicates, Earth Planet. Sci. Lett., 103 (1991)...

A novel oxygen vacancy assisted transition metal (TM) diffusion mechanism is proposed for the first time to explain the near-surface phase transformation in lithium excess transition metal layered oxides. Oxygen vacancies and TM migration have been observed at nm scale spatial resolution by Scanning Transmission Electron Microscopy and Electron Energy Loss Spectroscopy. Formation of (dilute) ox...

We have performed density functional calculations of oxygen incorporation and diffusion in monoclinic hafnia (HfO2) for a range of oxygen charge states. The calculations demonstrate that oxygen favors atomic incorporation and that O2- is the most stable species. We find that oxygen interstitials diffuse via exchange with lattice oxygen sites in hafnia, and that O- species have the smallest diff...

Engineered tissue constructs are limited in size, and thus clinical relevance, when diffusion is the primary mode of oxygen transport. Understanding the extent of oxygen diffusion and cellular consumption is necessary for the design of engineered tissues, particularly those intended for implantation into hypoxic wound sites. This study presents a combined experimental and computation model to p...

A simple mathematical model of steady state  oxygen distribution subject to diffusive transport and non- linear uptake in a retinal cylinder has been developed. The approximate analytical solution to a reaction- diffusion equation are obtained by using series expansions. The computational results for the scaled variables are presented through graphs. The effect of the important parameters (1) d...