The eternal inflation scenario predicts that our observable Universe resides inside a single bubble embedded in a vast inflating multiverse. We present the first observational tests of eternal inflation, performing a search for cosmological signatures of collisions with other bubble universes in cosmic microwave background data from the WMAP satellite. We conclude that the WMAP 7-year data do n...

We study the influence of bubble-bubble interactions on the propagation of linear acoustic waves in bubbly liquids. Using the full model proposed by Fuster and Colonius [J. Fluid Mech. 688, 253 (2011)], numerical simulations reveal that direct bubble-bubble interactions have an appreciable effect for frequencies above the natural resonance frequency of the average size bubble. Based on the new ...

Direct measurements of individual bubble oscillations in lithotripsy fields have been performed using light-scattering techniques. Studies were performed with bubble clouds in gassy water as well as single levitated bubbles in degassed water. There is direct evidence that the bubble survives the inertial collapse, rebounding several times before breaking up. Bubble dynamics calculations agree w...

The characteristics of bubble motion in non-Newtonian liquids are still not well understood because many parameters influence the terminal rise velocity, trajectory and shape of bubbles (Frank, 2003). As the bubble motion is a complex problem, the degree of the complexity increases with bubble size (Kulkarni and Joshi, 2005). When bubble rises through liquid, the most resistance will be imposed...

Let B be the operation of re-ordering a sequence by one pass of bubble sort. We completely answer the question of when the inverse image of a principal pattern class under B is a pattern class.

A bubble initiated near a rigid boundary may be almost in contact with the boundary because of its expansion and migration to the boundary, where a thin layer of water forms between the bubble and the boundary thereafter. This phenomenon is modelled using the weakly compressible theory coupled with the boundary integral method. The wall effects are modelled using the imaging method. The numeric...

The complex dynamics of a single bubble of a few millimeters in size oscillating inside a narrow fluid-filled gap between two parallel plates is studied using high-speed videography. Two synchronized high-speed cameras were used to observe both the side and front views of the bubble. The front-view images show bubble expansion and collapse with the formation of concentric dark and bright rings....

To investigate the hydrodynamic behaviour of industrial scale bubbling fluidised bed reactors, a 3D Discrete Bubble Model (DBM) has been developed. In the DBM, an Euler-Lagrange model, the bubbles are treated as discrete elements and the bubble trajectories are tracked individually, while the emulsion phase is considered as a continuum and is described with the continuity and Navier-Stokes equa...

p olicy makers in housing sector seeks to use instruments by which they can control volatility of housing price and prevent high disturbances of the bubble and price shocks, or at least, reduce them. in the portfolio and speculation theories, it is emphasized that speculative demand for housing is the main cause of shocks and price volatilities in the sector. the theory of housing price bubble ...