Oxygen saturation

In aerated or oxygen saturated solutions, the fullerene triplet lifetime suffers a marked reduction [147, 148]. 

Another example is dissolved oxygen (DO). The amount of DO water can hold at saturation is affected by both temperature and salinity. The warmer and/or saline the water, the lower the saturation DO level. Oxygen saturation is also affected by atmospheric pressure. The saturation oxygen level decreases as elevation increases. 

In the case of a less soluble gas such as oxygen, diffusion occurs so slowly through the Hquid film that only a small concentration difference is required to overcome the resistance of the gas film. Thus the Hquid film at the interface is considered to be very close to oxygen saturation and it is not necessary to consider gas film resistance in the calculation (14). 

In addition to COg, Cl and BPG also bind better to deoxyhemoglobin than to oxyhemoglobin, causing a shift in equilibrium in favor of Og release. These various effects are demonstrated by the shift in the oxygen saturation curves for Hb in the presence of one or more of these substances (Figure 15.35). Note that the Og-binding curve for Hb + BPG + COg fits that of whole blood very well. 

The importance of the BPG effect is evident in Figure 15.35. Hemoglobin stripped of BPG is virtually saturated with Og at a pO of only 20 torr, and it cannot release its oxygen within tissues, where the jbOg is typically 40 torr. BPG shifts the oxygen saturation curve of Hb to the right, making the Hb an Og... 

FIGURE A15.3 Oxygen saturation curve for Hb in the form of Fversus pO, assuming n =... 

Fig. 2.12 Potential-time curves on mild steel in sodium borate/hydrochloric acid buffer solutions, pH 7-60, oxygen-saturated solution (after Ashworth )...

A potential pH diagram for the Pd-HjO-Cl system is presented and described whilst the rest potentials of palladium electrodes in oxygen-saturated solutions of different pH values have been determined . From the latter, dEr/dpH = — 65 mV in acid and —35 mV in alkaline solutions, and dEr/dlgPoj = 30 mV for both pH ranges. 

Example 2 Finely divided gold is agitated with an oxygen-saturated alkali-cyanide solution of pH = 12 containing 10 moldm of CN . Calculate the concentration of Au(CN)2 ions in solution at 25°C when the reaction is at equilibrium. The standard chemical potentials of the species involved (in kJ) are CN, 165 HjO, —237 Au(CN)f, 244 OH", —157. Assume that fl jo = 1, and take 2-303RT = 5710. 

Atmospheric Reaeration. Interfacial properties and phenomena that govern oxygen concentrations in river systems include 1) oxygen solubility (temperature, partial pressure and surface dependency), 2) rate of dissolution of oxygen (saturation level, temperature and surface thin film dependency, i.e., ice, wind), and 3) transport of oxygen via mixing and molecular diffusion. A number of field and empirically derived mathematical relationships have been developed to describe these processes and phenomena, the most common of which is (32) ... 

Fig. 8 Temperature, dissolved oxygen saturation, and conductivity profiles in the Sau and Susqueda reservoirs during a water transfer in 2005. Gray banners indicate the depth of the spillways (actual withdrawal depth indicated as an arrow). The path of the Sau Reservoir water inside Susqueda is indicated as a black thick arrow...

Fig. 10 Temperature, dissolved oxygen saturation, and conductivity profiles recorded in reservoirs from the Llobregat basin during the summer of 2005. Despite 6 months of stratification, oxygen saturation still showed high values except in La Baells. Compare these profiles with those from the Ter River reservoirs in Fig. 8...

Chan K-H, Miller JD, Dearden NM, Andrews PJ, Midgley S. The effect of changes in cerebral perfusion pressure upon middle cerebral artery blood flow velocity and jugular bulb venous oxygen saturation after severe brain injury. J Neurosurg 1992 77(1) 55-61. 

Figure 15.7 Logarithm of the kinetic current for the ORR in oxygen-saturated liquid electrolytes versus inverse diameter for Pt particles supported on Vulcan XC-72 (1) 0.9 V vs. RHE at 60 °C [Gasteiger et al., 2005] (2) 0.85 V vs. RHE at room temperature [MaiUard et al., 2002] (3)0.85 V vs. SHE at room temperature [Guerin etal., 2004]. For curves 1 and 2, measurements were performed with the thin-layer RDE in 0.1 M HCIO4 for curve 3, they were performed with stationary voltammetry in 0.5 M H2SO4. (Curves have been replotted from MaiUard et al. [2002] Gasteiger et al. [2005], Copyright 2002 and 2005, with permission from Elsevier and from Guerin et al. [2004], Copyright 2004 American Chemical Society.)...

Figure 16.8 Pt/TiO c-catalyzed oxygen reduction potential, where 0.01 mA cm is reached during the negative scan in a cyclic voltammetry experiment (scan rate 20 mV s ) in oxygen-saturated 0.5 M HCIO4 at 25 °C. (See color insert.)...

Central venous (superior vena cava) or mixed venous oxygen saturation >70%... 

A recent study would support a mixed venous oxygen saturation of 65% as similar to a central venous oxygen saturation of 70% ... 

Oxygen saturation not improving ° Admit to hospital ward... 

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