Near-critical phenomena

The invitations to participants suggested that the written papers concern Fast Adiabatic Phase Changes in Fluids and Related Phenomena. Particular topics suggested were Liquefaction shockwaves and Shock splitting Evaporation waves Condensation in Laval nozzles and turbines Stability in multiphase shocks Non-equilibrium and near-critical phenomena Nucleation in dynamic systems Structure of transition layers Acoustic phenomena in two-phase systems and Cavitation waves. All of these topics should have been treated with emphasis on physical results, new phenomena and theoretical models. Participants from fourteen nations took part in the Symposium and presented papers which were within the range of suggested topics. 

Generally, the metastability is a phenomenon associated with the persistence of the given phase well below the stability domain, bordered by the first order transition, for instance (/) the glass transition phenomenon, (//) metastable systems studies linked to spinodals - absolute stability limits, with particular attention towards the inherently metastable negative pressure domain (///) metastability near a critical point, (/v) the quest for the liquid - liquid near-critical transition in one component liquid, (v) the issue of liquid crystals where... 

It is often suggested that L-L transition in one component liquids is always "secret"", for instance hidden below the glass temperature, and then the evidence for its existence is non-direct. The most classical examples for this phenomenon are water or and triphenyl phosphite (TPP)." Recently clear evidence for the L-L near critical transition in the experimentally available domain for two novel liquids of vital technological and environmental significance have been given. They are nitrobenzene and trans-1,2-dichlorethylene. ... 

As is by now evident to the reader, the phenomenon of solubility in supercritical fluids is not new. Since 1879 (or 1861, if we include the high-pressure, near-critical liquid carbon dioxide studies of Gore), solubility, phase, and spectroscopic studies have been performed on a large number of solute-SCF mixtures. They were made for their inherent scientific and technical interest and value. And they received a resurgence of interest with the work of Diepen, Scheffer, and coworkers in the late 1940s and early 1950s. 

Near-Wall Bubble Crowding and Vapor Blanketing. Here, a layer of vapor bubbles builds up near the wall and this prevents the ingress of liquid to the tube surface, leading to a decrease in efficiency of cooling and to the critical phenomenon. 

However, current thermodynamic theories of compositional equilibrium under the combined influence of gravity and temperature fields do not adequately explain the large compositional gradients that are often encountered, except at conditions close to critical (Schulte 1980 Holt et al. 1983 Creek Schrader 1985 England et al. 1987 Nutakki et al. 1996). It is now quite common for the phenomenon of strong compositional grading to be associated with near-critical fluids, but the definition of near-critical fluids is rather broad and hazy Another problem with these theories is that they often do not predict the shape of these compositional depth trends at all well. In fact, Hoier Whitson (2001) doubt that most petroleum fields satisfy the fundamental assumptions in these models, especially that of zero mass flux (i.e. stationary state equilibrium). 

Family [9] considered the conformations of statistical branched fractals (which simulate branched polymers) formed in equilibrium processes in terms of the Flory theory. Using this approach, he found only three different states of statistical fractals, which were called uncoiled, compensated, and collapsed states. In particular, it was found that in thermally induced phase transitions, clusters occur in the compensated state and have nearly equal fractal dimensions ( 2.5). Recall that the value df = 2.5 in polymers corresponds to the gelation point this allows gelation to be classified as a critical phenomenon. 

Near the critical temperatures of both lower and upper consolute boundaries, the spatial correlations of densities within the liquid-phase sfructure extend over longer-than-usual distances. Near-critical liquids display, for this reason, unusually intense scattering of visible light ( critical opalescence ), but this phenomenon is in no sense unique to surfactant solutions. Critical opalescence is universally observed near critical points, even in one-component systems such as carbon dioxide, water, and so forth [68]. 

Here, 1 will introduce another type of the fluctuation as an example for the isotropic-nematic phase transition, which is a weak first-order transition and large fluctuations of the order parameter appear as a critical phenomenon near... 

There is evidence to suggest that the yield stress of thin hlms grows with the time of experiments, over a remarkably long duration—minutes to hours, depending on the liquid involved. Figure 9 gives the critical shear stress of OMCTS, measured by Alsten and Granick [26], as a function of experiment time. The yield stress on the hrst measurement was 3.5 MPa, comparable to the result presented in Ref. [8], but this value nearly tripled over a 10-min interval and then became stabilized as the time went on. This observation provides a possible explanation for the phenomenon that static friction increases with contact time. 

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