Effects Of Oxygen Depletion Research Articles

Effects of Oxygen Depletion on In Vitro Metabolism of Dimethylnitrosamine in Microsomes From Rat Liver and Human Tissues2

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Predictions of laminar flame speeds in boron-oxygen-nitrogen dust clouds

A detailed model of boron-oxygen-nitrogen dust-cloud flames including consideration of the details of boron particle ignition and the effects of oxygen depletion has been developed and used for prediction of flame speeds as functions of numerous parameters. Reasonably good agreement between measured flame speeds for the only two data points available on laminar boron dust cloud combustion and those predicted by this model has been obtained, although uncertainty concerning details of the experimental parameters results in this agreement being somewhat inconclusive. In addition, a simplified closed-form flame speed expression has been developed and the effects on predicted flame speeds of the various assumptions used in its development have been examined. The models have been used to study the effects of initial temperature, pressure, initial oxygen mole fraction, weight fraction particles, initial particle size, initial thickness of the oxide coating on the particles, radiation feedback from the postflame zone, and Nusselt Number. Mechanisms leading to the predicted dependencies are discussed.

Effects of pyrolysis-gas chemical reactions on surface recession of charring ablators.

Oxygen depletion effect in chemical reactions between pyrolysis gases and air stream on surface recession of charring ablators

A study of radiation properties of oxide-metal composites.

Simulation of Convective and Radiative Entry Heating, Advances in Hypervelocity Techniques, edited by A. M. Krill, Plenum, New York, 1962. 5 Marvin, J. G. and Pope, R. B., Laminar Convective Heating and Ablation in the Mars Atmosphere, AIAA Journal, Vol. 5, No. 2, Feb. 1967, pp. 240-248. 6 Wilson, G. R. (compiler), Thermophysical Properties of Six Charring Ablators from 140° to 700 °K and Two Chars from 800° to 3000°K, TN D-2991, Oct. 1965, NASA. 7 Parker, J. A., Needs for Characterization and Process Control of Low-Density Composites for Aerospace Application, presented at International Society of Plastics Institute, New York, June 1966. 8 Vojvodich, N. S. and Pope, R. B., /The Influence of Ablation on Stagnation Region Convective Heating for Dissociated and Partially Ionized Boundary Layer Flows, Proceedings of the 1965 Heat Transfer and Fluid Mechanics Institute, edited by A. F. Charwat et al., Stanford University Press, Stanford, Calif., 1965. 9 Pope, R. B., Stagnation-Point Convective Heat Transfer in Frozen Boundary Layers, Paper 68-15, Jan. 1968, AIAA. 10 Scala, S. M. and Gilbert, L. M., Sublimation of Graphite at Hypersonic Speeds, AIAA Journal, Vol. 3, No. 9, Sept. 1965, pp. 1635-1644. 11 Wakefield, R. M., Lundell, J. H., and Dickey, R. R., The Effect of Oxygen Depletion in Gas-Phase Chemical Reactions on the Surface Recession of Charring Ablators, Paper 68-302, April 1968, AIAA. 12 Emmons, H. W. and Leigh, D., Tabulation of the Blasius Function with Blowing and Suction, Combustion Aerodynamics Lab. Interim TR9 Nov. 1953, Div. of Applied Science, Harvard Univ.

The Chemical Protection of Pseudomonas Species against Ionizing Radiation

Many compounds have been reported to protect bacteria against ionizing radiation, and the most widely studied have been organic sulfhydryl compounds. In many instances the effect can be shown to be due to depletion of dissolved oxygen by autoxidation (1, 2), but there are at least two other ways in which organic sulfhydryl compounds can protect. Firstly, at low concentrations (0.001 M) they may exert a protective effect which is completely abolished by bubbling with air during irradiation (3). While this is also an oxygen-depletion effect, it is not, however, due to autoxidation but to a radiation-induced reaction involving the sulfhydryl compound in which oxygen is consumed.2 Secondly, some sulfhydryl compounds at high concentrations may afford protection which is not due to oxygen depletion (2, 4-6). With Escherichia coli this type of protection by cysteine needs a temperature-dependent period of incubation before irradiation (2). The aliphatic alcohols (e.g., glycerol) and, more recently, dimethyl sulfoxide (DMS) have also been shown conclusively to protect vegetative bacteria under controlled gas conditions (7-10). The present paper describes a similar action of thiourea and reports some experiments designed to indicate whether or not all the compounds mentioned protect against the same component of radiation damage.