Vacuum bubbles

Cavitation Formation of transient voids or vacuum bubbles in a liquid stream passing over a surface is called cavitation. This is often encountered arouna propellers, rudders, and struts and in pumps. When these bubbles collapse on a metal surface, there is a severe impact or explosive effec t that can cause considerable mechanical damage, and corrosion can be greatly accelerated because of the destruction of protective films. Redesign or a more resistant metal is generally required to avoid this problem. 

Cavitation Damage erosion of a solid surface caused by the collapse of vacuum bubbles formed in a fluid. 

This work initiated a whole new line of research at the intersection of elementary particle theory and cosmology (the theory of unstable vacuum, vacuum bubbles, vacuum strings, etc.). 

Using a syringe the phases were carefully separated and transferred to different vials. The ionic liquid phase was then submitted to an evaporation procedure (rotary evaporator, 50 °C, 10 mbar, 6 h). Shortly after connecting to vacuum bubble generation could be observed. 

By repeated application of this identity index 02 can be reduced to zero (see Fig.2) which implies that the calculation of 7(ai, 02) is reduced to the calculation of vacuum bubble integrals that do not dependent on the external momentum p. That is a significant simplification. 

The chief nonmineral application of froth flotation is to the removal or oil or grease or fibrous materials from waste waters of refineries or food processing plants. Oil droplets, for instance, attach themselves to air bubbles which rise to the surface and are skimmed off Coagulant aids and frothers often are desirable. In one kind of system, the water is saturated with air under pressure and then is pumped into a chamber maintained under a partial vacuum. Bubbles form uniformly throughout the mass and carry out the impurities. The unit illustrated in Figure 20.12 operates at 9 in. mercury vacuum and removes both skimmed and settled... 

The apparatus used is known as a microfluidizer with a high-pressure positive displacement pump (500-200 PSI). A microfluidizer consists of small channels called microchannels through which product flows on to an impingement area, resulting in very fine particles of submicron range when pressure is applied by the attached pump Similar to the sonication method, this is also useful for small-batch production of nanoemulsions. Shear forces generated by ultrasonic cavitation result in production of vacuum bubbles which disintegrate the particles to nanometer scale... 

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