Oxygen utilisation

The oxygen utilisation balanced with growth gives ... 

Chance, B. and Williams, G.R. (1955). Respiratory enzymes and oxidative phosphorylation. I. Kinetics of oxygen utilisation. J. Biol. Chem. 217, 383-393. 

Use of light in anaerobes produced oxygen, utilising novel incorporation of Mn, which generated 02. CaC03 was formed on the outside of cells. Porphyrin-bound Mg, Fe, Co, Ni and coenzyme-bound Mo appeared (three billion years ago). 

Organ or tissue metabolic rate kj/kg per day Contribution to whole-body REE (% total) Approx, oxygen utilisation of tissue for adult Equivalent rate glucose uptake ... 

Only two metal oxide lines (2Fe + 02 = 2FeO and 4/3 A1 + O2 = 2/3 AI2O3) are shown in the sample diagram (Fig. 5.4). In reality there are a large number of nearly parallel lines (for, say, CaO, MgO, Si02, BaO, K2O, Na20, etc.). All these lines are plotted on the basis of involvement of one mole of oxygen utilisation, e g. 

The MEAs of the MCFC are sandwiched between stainless steel or nickel bipolar plates, which collect current from, and distribute fuel/steam and oxidant air plus recirculated anode gas via the porous electrode structures to, the chemical reactions at the electrolyte/gas interfaces. Figure 5.1. In the long-anode, narrow-cathode, rectangular MTU fuel cell, fuel utilisation is about 80%, oxygen utilisation about 50%. 

I. A. Hassan, S. A. Spencer, Y. A. Wickramasinghe, and K. S. Palmer, Measurement of Peripheral Oxygen Utilisation in Neonates Using Near Infrared Spectroscopy Comparison Between Arterial and Venous Occlusion Methods, Early Hum. Devel., 57(3), 211-224 (2000). 

Takano, T. and Dickerson, R.E. (1982) in Electron Transport and Oxygen Utilisation (Chien, H. ed.), pp. 17-26, Elsevier/North-Holland, Amsterdam. 

Leenders, K. L., Beaney, R. P., Brooks, D. J., Lammertsma, A. A., Heather, J. D., and McKenzie, C. G. (1985) Dexamethasone treatment of brain tumour patients effects on regional cerebral blood flow, blood volume, and oxygen utilisation. Neurology 35, 1610-1616. 

Forster, S., Huettel, M. and Ziebis, W., 1996. Impact of boundary layer flow velocity on oxygen utilisation in coastal sediments. Mar. Ecol. Prog. Ser., 143 173-185. 

The scientific programme comprised four main themes photo-oxygen evolution superoxides, intermediates between oxygen and water biological oxygen transport and oxygen-utilising enzymes. 

Under normal physiological conditions the mitochondria are the major source of reactive oxygen species in the hepatocyte (Boveris and Cadenas 1997). Approximately 80-90 per cent of the oxygen utilised by hepatocytes is metabohsed by mitochondria (Thayer and Rubin 1982) and it is estimated that 2 per cent of the oxygen consumed is converted to superoxide anions (Boveris and Chance 1973). 

The fuel utilisation (FU) and oxygen utilisation (OU) are two of the most important control variables of the fuel cell. Fuel utilisation (t f) is defined as the ratio of the mass flow rate of the fuel taking part in the reaction to the mass flow rate of the fuel supplied to the cell. Oxygen utilisation (fo) is defined as the ratio of mass flow rate of oxygen consumed by the reaction to the mass flow rate of oxygen supplied to the cell. According to the operational requirement of the SOFC, FU must be maintained constant. Normally, FU of 0.8-0.9 is desired. In this case, a value of 0.8 is chosen for the FU and a value of 0.125 is chosen for the OU. 

Figure 7.1 Theoretical open circuit voltage for a hydrogen fuel cell under diffeent circumstances. The two curves for the voltage at the exit show how the voltage depends on fuel utilisation and temperature. In both cases the oxygen utilisation is 50%.

The results of durability tests of cells with LSCF cathodes (2.5G) are shown in Fig. 7. The objective of the test was to measure the degradation rate of the 2.5G cells at 650 °C at various current densities with a significant electrode polarisation. The results from ageing tests of 2.5G cells are compared to cells with LSM cathodes (2G) at 750 °C, 0.75 A/cm, 75-80 % fuel utilisation, 9 % oxygen utilisation in the figure. The current density and degradation rates observed are indicated in the graph. 

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