The wall effects on the axisymmetric rise and deformation of an initially spherical gas bubble released from rest in a liquid-filled, finite circular cylinder are numerically investigated. The bulk and gas phases are considered incompressible and immiscible. The bubble motion and deformation are characterized by the Morton number (Mo), Eötvös number (Eo), Reynolds number (Re), Weber number (We)...

Recent studies show that individual investors tend to speculate on stock markets and hold shares with a lottery-like return. For this speculation of people have a significant impact on stock returns, individual investors must trade the same shares with the same time. The purpose of this study was to investigate the effect of the speculative bubble on the stock returns of companies in Iran. Foll...

Recent observations of growing and collapsing bubbles in flows over axisymmetric headforms have revealed the complexity of the ' micro-fluid-mechanics ' associated with these bubbles (van der Meulen & van Renesse 1989; Briangon-Marjollet et al. 1990; Ceccio & Brennen 1991). Among the complex features observed were the bubble-tobubble and bubble-to-boundary-layer interactions which leads to the ...

A one-pot single-step novel process has been developed to form microbubbles up to 250 μm in diameter using a pressurized rotating device. The microbubble diameter is shown to be a function of rotational speed and working pressure of the processing system, and a modified Rayleigh-Plesset equation has been derived to explain the bubble-forming mechanism. A parametric plot is constructed to identi...

Bubble formation is a well identified phenomenon within short (ns) and ultrashort (fs) laser pulses-aqueous media interactions. Bubble formation might be produced by three different mechanisms: (1) optical breakdown, (2) rarefraction wave and (3) overheating of the material. Experiments where transparent and scattering tissue models that mimic biological tissue were irradiated with a Q-switched...

Effective treatment of vascular gas embolism may be possible with emulsified fluorocarbon compounds. We tested the hypothesis that a fluorocarbon emulsion delivered before gas embolization would enhance bubble motion through the vasculature, favoring more rapid clearance. Air microbubbles were injected into the rat cremaster microcirculation in six groups of rats receiving Perftoran, an emulsif...

The interfacial area transport equation for a subcooled boiling flow is developed with a mechanistic model for the wall boiling source term. It includes the bubble lift-off diameter model and the lift-off frequency reduction factor model. Those models take into account a bubble’s sliding on the heated wall after a departure from the nucleate site and the coalescences of sliding bubbles. To impl...

Acoustic cluster technology (ACT) is a two-component, microparticle formulation platform being developed for ultrasound-mediated drug delivery. Sonazoid microbubbles, which have a negative surface charge, are mixed with micron-sized perfluoromethylcyclopentane droplets stabilized with a positively charged surface membrane to form microbubble/microdroplet clusters. On exposure to ultrasound, the...

We investigate experimentally the behavior of liquid foams pumped at a given flow rate through a single pore, in the situation where the pore diameter is smaller than the bubble diameter. Results reveal that foam invasion can be observed only within a restricted range of values for the dimensionless flow rate and the foam liquid fraction. Within this foam invasion regime, the liquid content of ...