scholarly journals An Experimental Study on Oxidation Rate of Coal: The Influence of Oxygen Concentration

2015 ◽  
Author(s):  
Bucai Ma ◽  
Youqiang Chen ◽  
Yinlei Yang ◽  
Ying Zhu
Keyword(s):  
Experimental Study ◽  
Oxygen Concentration ◽  
Oxidation Rate

The experimental study on the performance of a small-scale oxygen concentration by PSA

2005 ◽  
Vol 42 (2) ◽  
pp. 123-127 ◽  
Author(s):  
Z. Yuwen ◽  
W. Yuyuan ◽  
G. Jianying ◽  
Z. Jilin
Keyword(s):  
Experimental Study ◽  
Oxygen Concentration ◽  
Small Scale

Myringosclerosis Caused by Increased Oxygen Concentration in Traumatized Tympanic Membranes Experimental Study

1995 ◽  
Vol 104 (8) ◽  
pp. 625-632 ◽  
Author(s):  
Cecilia Mattsson ◽  
Karin Magnuson ◽  
Sten Hellström
Keyword(s):  
Experimental Study ◽  
Oxygen Concentration ◽  
Middle Ear ◽  
Oxygen Radicals ◽  
Ambient Air ◽  
Fourth Group ◽  
Oxygen Concentrations ◽  
Tympanic Membranes

The purpose of this study was to elucidate possible relationships between the oxygen concentration of the middle ear cavity and the development of myringosclerosis. Three groups of rats with myringotomized tympanic membranes were exposed to different oxygen concentrations of 10%, 15%, and 40%, respectively, for 1 week. A fourth group was kept in ambient air. Two other groups of rats with myringotomized and intubated tympanic membranes were exposed to oxygen concentrations of 10% and 40%, respectively, for the same period of time. Otomicroscopically, all hyperoxic animals had more numerous myringosclerotic lesions compared with the ambient air group, and also displayed a pronounced hyperplasia of the keratinizing epithelium around the perforation border. By contrast, the hypoxic animals showed less pronounced myringosclerotic lesions or even completely lacked them. It is inferred that an increased oxygen concentration in the middle ear cavity will increase the likelihood of myringosclerotic deposits. The mechanism involved could be related to the formation of oxygen radicals.

Non-toxic alveolar oxygen concentration without hypoxemia during apnoeic oxygenation: an experimental study

2011 ◽  
Vol 55 (9) ◽  
pp. 1078-1084 ◽  
Author(s):  
S. HÖSTMAN ◽  
J. ENGSTRÖM ◽  
F. SELLGREN ◽  
G. HEDENSTIERNA ◽  
A. LARSSON
Keyword(s):  
Experimental Study ◽  
Oxygen Concentration ◽  
Alveolar Oxygen ◽  
Apnoeic Oxygenation

scholarly journals Development and evaluation of silicone membrane as aerators for membrane bioreactors

2005 ◽  
Author(s):  
◽  
Xolani Proffessor Mbulawa
Keyword(s):  
Mass Transfer ◽  
Experimental Study ◽  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Silicone Rubber ◽  
Convective Transport ◽  
Operating Conditions ◽  
Pure Oxygen ◽  
Bulk Liquid ◽  
Dissolved Oxygen Concentration

In bubble-less aeration oxygen diffuses through the membrane in a molecular form and dissolves in the liquid. Oxygen is fed through the lumen side of silicone rubber tube. On the outer surface of the membrane there is a boundary layer that is created by oxygen. This then gets transported to the bulk liquid by convective transport created by water circulation through the pump. The driving force of the convective transport is due to concentration difference between the dissolved oxygen in water and oxygen saturation concentration in water at a particular temperature and pressure. The design of a membrane aerated bioreactor needs an understanding of the factors that govern oxygen mass transfer. It is necessary to know the effects of operating conditions and design configurations. Although various methods of bubble-less aeration have been reported, there still exists a lack of knowledge on the immersed membrane systems. This study is aiming at contributing to the development of an immersed membrane bioreactor using silicone rubber tubular membrane as means of providing oxygen. The secondary objective was to investigate the influence that the operating conditions and module configuration have on the system behaviour. From the experimental study, the characteristic dissolved oxygen -time curve show that there is a saturation limit equivalent to the equilibrium dissolved oxygen concentration, after which there is no increase in dissolved oxygen with time. At ambient conditions the equilibrium dissolved oxygen is approximately 8 mg/L. This is when water is in contact with air at one atmospheric pressure. At the same conditions the equilibrium dissolved oxygen concentration when water is in contact with pure oxygen is approximately 40 mg/L. This is why all the experiments were conducted from 2mg/L dissolved oxygen concentration in water, to enable enough time to reach equilibrium so as to determine mass transfer coefficient. The most important parameters that were investigated to characterise the reactor were, oxygen supply pressure, crossflow velocity, temperature and module orientation. Observations from the experimental study indicated that when the system is controlled by pressure, crossflow does not have a significant effect on mass transfer. When the system is controlled by the convective transport from the membrane surface to the bulk liquid, pressure does not have a significant effect on mass transfer. All four effects that were investigated in the study are discussed.

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