Investigation of turbulency on the rate of induced liquid circulation, gas hold-up, mixing time and overall gas–liquid volumetric oxygen mass transfer coefficient. The various types of surfactants (containing Brij58, TritonX-405, Tween40, HCTBr) with various concentrations of 1-5 ppm were examined on the operational characteristics of the reactor. In surfactant solutions (in comparison with pur...

A discrete-bubble model that predicts the rate of oxygen transfer in diffused-bubble systems is evaluated. Key inputs are the applied gas flow rate and the initial bubble size distribution. The model accounts for changes in the volume of individual bubbles due to transfer of oxygen and nitrogen (and hence changing partial pressure), variation in hydrostatic pressure, and changes in temperature....

Hot electrons are generated in Si(001) at 295 K via linear absorption of .4.3 eV photons or by threephoton processes using 270 fs, 800 nm (1.55 eV) optical pulses. Electron trapping in oxide films is observed via time-dependent optical second harmonic generation induced by the electric field associated with charge transfer. For anodically oxidized samples and constant beam irradiance, the trans...

Two respirometric principles are combined in an experimental setup based on a laboratory scale batch reactor and applied to the characterization of activated sludge and wastewater. In the first respirometric principle the temporary disturbance of the dissolved oxygen concentration in the reactor is used to estimate the respiration rate. To this end, the oxygen mass-transfer must be calculated a...

Rotating biological contactor is being widely used for wastewater treatment but there is an apparent lack of knowledge about the rate at which oxygen transfer occurs, in physical and biological system. In this study the transfer of oxygen from air to water by a rotating disc air-liquid contactor in physical system is investigated. The oxygen transfer model suggested by Kim and Molof, Water Sci....

The role of light as an energy source for slightly aereated cultures of halobacteria was studied, using continuous cultures with low nutrient concentrations and a low oxygen supply. A series of experiments were carried out with non-illuminated and differently illuminated cultures and with different oxygen transfer rates. Under low oxygen availability, light proved to be a decisively important e...

Recovery of postischemic function may be limited by energy synthesis by mitochondria, energy transfer via the creatine kinase reaction, or energy utilization at myofibrils. To identify the limiting step, we defined the relations among oxygen consumption, creatine kinase reaction velocity and cardiac performance in myocardium reperfused following mild, moderate, and severe ischemia. Isolated iso...

The rate of oxygen utilization by the electron transport system at low oxygen concentrations has been difficult to explain mechanistically (l-3). As in most enzymatic reactions the rate of oxygen utiliiation is independent of oxygen concentration when the oxygen concentration is high, but becomes dependent upon the oxygen concentration at some critical value of the oxygen tension. Chance (4) ha...

The oxygen carrying performance of a perfluorooctyl bromide (PFOB) emulsion is considered. The intended purpose is to enhance hepatocyte growth and function in a bio-artificial liver support system (BALSS). Such oxygen carrying emulsions have previously been used in biological systems (e.g. cell culturing). However, optimum emulsion characteristics for enhanced oxygen mass transfer have not bee...