Expanding bubble

From Eq. (89), the surface tension is seen to influence the bubble volume in two ways, viz. by varying the flow rate in the expanding bubble, and by causing a downward force at the periphery of the orifice. Even if the effect of the surface tension becomes negligible at the orifice tip due to either the small size of the orifice or the nonwettable character of the system, it still influences the bubble volume because of the variations in flow during the bubble formation. [Pg.312]

If we neglect, momentarily, any surface tension effects (i. e. 2a/Rq 0) and assume that the liquid contains only a small amount of gas (Pg 0), then we may deduce that expanding bubbles are created in a liquid when the vapour pressure exceeds the atmospheric pressure (P, > Pj ). For water the vapour pressure at 100 °C is 1 atm and hence water, at a hydrostatic pressure of 1 atm, boils as soon as the temperature exceeds 100 °C. At 25 °C the vapour pressure of water is 0.023 atm and thus water will only boil, at 25 °C, if the atmospheric pressure is less than this value. This can readily be achieved by evacuating the system. [Pg.42]

Replication of the bacterial chromosome commences at a unique site, the origin, and replication forks diverge from this site at approximately equal rates. Consequently, the origin is duplicated completely and each daughter origin remains at the central portion of the expanding bubble. This is in contrast to unidirectional replication, which would leave the origin only partially replicated and located at the stationary fork as the replication fork moved away. [Pg.482]

The principal manifestation of the bends is a deep boring ache or pain in the bones of muscles around the joints. The intensity of the pain can vary. This symptom may be accompanied by neurocirculatory collapse. The cause of the pain is thought to be due to excitation of mechanoreceptors as a result of tissue distortion by the expanding bubbles, or to ischemic excitation due to interference with vascular flow. The role of humoral agents in the production of pain should not be overlooked (K9). Even following the standard U. S. Navy Decompression Tables the incidence of bends may be as high as 4%, depending on age, physical condition, etc. [Pg.113]

As already noted, when the LE phase is expanded, bubbles of gas grow and thin lamellae of fluid are left between them, forming a two-dimensional foam structure (Fig. 10a) in which the size of the cells and the distribution of the number of sides changes with time. Dendritic structures (Fig. 21) are observed in the LE-LC transition region when the monolayer is compressed, or in temperature quenches from the LE one-phase region into the two-phase region. In the case of fatty acids,only circular islands are observed at low temperature, even with rapid compression. The temperature threshold for the appearance of dendritic patterns is quite sharp. Such structures are also found in phospholipid monolayers. ... [Pg.446]

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