Drag reduction by bubbles in stationary turbulent flows is sensitive to the compressibility of the bubbles. Without this dynamical effect the bubbles only renormalize the fluid density and viscosity, an effect that by itself can only lead to a small percentage of drag reduction. We show in this paper that the dynamics of bubbles and their effect on the compressibility of the mixture can lead to...

OBJECTIVES This study sought to evaluate the effect of catheter-based patent foramen ovale (PFO) closure on the occurrence of arterial bubbles after simulated dives. BACKGROUND PFO is a risk factor of decompression sickness in divers due to paradoxical embolization of bubbles. To date, the effectiveness of catheter-based PFO closure in the reduction of arterial bubbles has not been demonstrat...

Shan-Chen model is a numerical scheme to simulate multiphase fluid flows using Lattice Boltzmann approach. The original ShanChen model suffers from inability to accurately predict behavior of air bubbles interacting in a non-aqueous fluid. In the present study, we extended the Shan-Chen model to take the effect of the attraction-repulsion barriers among bubbles in to account. The proposed model...

BACKGROUND The observation of ultrasound generated cavitation bubbles deep in tissue is very difficult. The development of an imaging method capable of investigating cavitation bubbles in tissue would improve the efficiency and application of ultrasound in the clinic. Among the previous imaging modalities capable of detecting cavitation bubbles in vivo, the acoustic detection technique has the ...

Whereas bubble growth out of gas-oversatured solutions has been quite well understood, including the formation and stability of surface nanobubbles, this is not the case for bubbles forming on catalytic surfaces due to catalytic reactions, though it has important implications for gas evolution reactions and self-propulsion of micro/nanomotors fueled by bubble release. In this work we have fille...

Exercise may produce micronuclei (presumably gas-filled bubbles) in tissue, which could serve as nucleation sites for bubbles during subsequent decompression stress. These micronuclei have never been directly detected in humans. Dual-frequency ultrasound (DFU) is a resonance-based, ultrasound technique capable of detecting and sizing small stationary bubbles. We surveyed for bubbles in the legs...

This paper derives the difference in pressure between the beginning and the end of a rectangular microchannel through which a flowing liquid (water, with or without surfactant, and mixtures of water and glycerol) carries bubbles that contact all four walls of the channel. It uses an indirect method to derive the pressure in the channel. The pressure drop depends predominantly on the number of b...

nowadays, the use of innovative nano-technology in the food industry quality control has significantly increased and it is widely employed in numerous fields such as diagnosis of microbial toxin of foods using nano-biosensors, increasing food shelf-life with the help of nano-clay and nano-silver packaging, as well as changing some of the unpleasant organoleptic properties such as taste, color, ...

although the solubility of oxygen in molten aluminum alloys is said to be negligible, the fresh surface of the melt oxidizes quickly in the air and an oxide film is formed on the melt surface. oxide-metal-oxide sandwich technique is a method for the study of short-time surface oxide films. in this research, air was blown at 0.5 atmosphere into the melts of al-1mg and al-6mg alloys by means of a...

Computational fluid dynamics was used and a numerical simulation analysis of boiling heat transfer in microchannels with three depths cross-sectional profiles conducted. The coefficient bubble generation process microchannel structures width 80 μm depth 40, 60, were compared during the process, factors influencing studied. A visual test bench built, substrates different sizes prepared using mic...