Negative Bubbles and Unpredictability of Financial Markets: The Asian Currency Crisis in 1997

We obtain the three following conclusions. First, business cycles depend on prices of stocks and primary commodities such as crude oil. Second, stock prices and oil prices generate psychological cycles with different periods. Third, there exist cases of "negative bubble" under certain conditions. Integrating the above results, we can find a role of a government in financial market in developing countries.

Dynamics of gas bubbles encapsulated by a viscoelastic fluid shell under acoustic fields

The dynamics of a gas-filled microbubble encapsulated by a viscoelastic fluid shell immersed in a Newtonian liquid and subject to an external pressure field is theoretically studied. The problem is formulated by considering a nonlinear Oldroyd type constitutive equation to model the rheological behavior of the fluid shell. Heat and mass transfer across the surface bubble have been neglected but radiation losses due to the compressibility of the surrounding liquid have been taken into account. Bubble collapse under sudden increase of the external pressure as well as nonlinear radial oscillations under ultrasound fields are investigated. The numerical results obtained show that the elasticity of the fluid coating intensifies oscillatory collapse and produces a strong increase of the amplitudes of radial oscillations which may become chaotic even for moderate driving pressure amplitudes. The role played by the elongational viscosity has also been analyzed and its influence on both, bubble collapse and radial oscillations, has been recognized. According to the theoretical predictions provided in the present work, a microbubble coated by a viscoelastic fluid shell is an oscillating system that, under acoustic driving, may experience volume oscillations of large amplitude, being, however, more stable than a free bubble. Thus, it could be expected that such a system may have a suitable behavior as an echogenic agent.

The stability of air bubbles in the sea and the effect of bubbles and particles in the extinction of sound and light in sea water /

Mode of access: Internet.

Soap-bubbles, their colours and the forces which mould them ; being the substance of many lectures delivered to juvenile and popular audiences with the addition of several new and original sections /

Mode of access: Internet.

Salt water bubbles; or, Life on the wave.

Added t.-p., illustrated.

Bubbles; a comedy in three acts ...

Mode of access: Internet.

Soap-bubbles, their colours, and the forces which mould them. Being the substance of many lectures delivered in the theatre of the London institution on the afternoons of Dec. 30, 1889, Jan. 1 and 3, 1890, before a juvenile audience,

Mode of access: Internet.

Soap-bubbles and the forces which mould them. Being a course of three lectures delivered in the theatre of the London Institution on the afternoons of Dec. 30, 1889, Jan. 1 and 3, 1890, before a juvenile audience.

Available on demand as hard copy or computer file from Cornell University Library.

Bubbles of the day : a comedy, in five acts /

"Performed at the Theatre royal, Covent Garden."

South-sea bubbles.

Mode of access: Internet.

Soap bubbles.

Tr. of Seifenblasen.

A comparison between capillary and imaging techniques for sizing bubbles in flotation systems

This communication reports a laboratory and plant comparison between the University of Cape Town (UCT) device (capillary) and the McGill University bubble sizing method (imaging). The laboratory work was conducted on single bubbles to establish the accuracy of the techniques by comparing with a reference method (capture in a burette). Single bubble measurements with the McGill University technique showed a tendency to slightly underestimate (4% for a 1.3 mm bubble) and the UCT technique to slightly overestimate (1% for the 1.3 man bubble). Both trends are anticipated from fundamental considerations. In the UCT technique bubble breakup was observed when measuring a 2.7 mm bubble using a 0.5 mm ID capillary tube. A discrepancy of 11% was determined when comparing the techniques in an industrial-scale mechanical flotation cell. The possible sources of bias are discussed. (C) 2003 Elsevier Ltd. All rights reserved.