INTRODUCTION Bubble columns are widely used in industrial gas-liquid operations (e.g. gas-liquid reactions, fermentations) in chemical and biochemical processes industries, due to their simple construction, low operating cost and high-energy efficiency. In all these processes, gas hold-up and bubble size are important design parameters since they define the gasliquid interfacial area available ...

BACKGROUND Thousands of air bubbles enter the cerebral circulation during cardiac surgery, but whether high numbers of bubbles explain post-operative cognitive decline is currently controversial. This study estimates the size distribution of air bubbles and volume of air entering the cerebral arteries intra-operatively based on analysis of transcranial Doppler ultrasound data. METHODS Transcr...

Engineering analyses combined with experimental observations in horizontal tubular photobioreactors and vertical bubble columns are used to demonstrate the potential of pneumatically mixed vertical devices for large-scale outdoor culture of photosynthetic microorganisms. Whereas the horizontal tubular systems have been extensively investigated, their scalability is limited. Horizontal tubular p...

The 1999 eruption of Shishaldin volcano (Alaska, USA) displayed both Strombolian and Subplinian basaltic activity. The Subplinian phase was preceded by a signal of low amplitude and constant frequency (c2 Hz) lasting 13 h. This bhumming signalQ is interpreted as the coalescence of the very shallow part of a foam building up in the conduit, which produces large gas bubbles before bursting. The a...

In bubble-laden flows with large local or global void fraction the distance between bubbles is small so that these interact with a certain probability. During interaction, the bubble can either bounce or undergo coalescence, depending on the nature of the interaction. Coalescence as well as bubble breakup alter the bubble size distribution and consequently change the dynamics of individual bubb...

An understanding of bubble flows is important in the design of process equipment, particularly in the chemical and power industries. In vapour-liquid processes the mass and heat transfer between the phases is dominated by the liquid-vapour interface and is determined by the number, size and shape of the bubbles. For bubble flows these characteristics are often controlled by the generation mecha...

In this paper, effects of EHD actuators on hydrodynamic behavior and heat transfer of air flow over a circular cylinder were considered. Pressure and temperature distributions around the cylinder were measured in presence of wire-plate EHD actuators. The Reynolds number based on cylinder diameter (d) were 3500, 7000. Experiments were performed for various configurations. Based on obtained resul...