Aggregation, fast

Other properties of association colloids that have been studied include calorimetric measurements of the heat of micelle formation (about 6 kcal/mol for a nonionic species, see Ref. 188) and the effect of high pressure (which decreases the aggregation number [189], but may raise the CMC [190]). Fast relaxation methods (rapid flow mixing, pressure-jump, temperature-jump) tend to reveal two relaxation times t and f2, the interpretation of which has been subject to much disagreement—see Ref. 191. A fast process of fi - 1 msec may represent the rate of addition to or dissociation from a micelle of individual monomer units, and a slow process of ti < 100 msec may represent the rate of total dissociation of a micelle (192 see also Refs. 193-195). 

Niu S and Mauzerall D 1996 Fast and efficient charge transport across a lipid bilayer is electronically mediated by Cyf, fullerene aggregates J. Am. Chem. Soc. 118 5791-5... 

Too fast a rate of addition may cause aggregation of the lithium. If this occurs, the addition should be interrupted and the rate of stirring diminished until the aggregate has disintegrated. 

To escape aggregative fluidization and move to a circulating bed, the gas velocity is increased further. The fast-fluidization regime is reached where the soHds occupy only 5 to 20% of the bed volume. Gas velocities can easily be 100 times the terminal velocity of the bed particles. Increasing the gas velocity further results in a system so dilute that pneumatic conveying (qv), or dilute-phase transport, occurs. In this regime there is no actual bed in the column. 

We have proposed that vesicle aggregation is probably related to the disposition of pardaxin bound in the phosphatidylserine vesicle lipid bilayer (26). This conclusion is supported by the observation that phosphatidycholine vesicles are not induced to aggregate and that the pardaxin-induced phosphatidylserine vesicle aggregation is affected by charge polarization of the vesicle (26). This suggestion seems to be consistent also with the voltage dependence of fast "pore" activity of pardaxin, the channels which are open only at positive membrane potentials. 

Micelles the mostly spherical nanoscale aggregates formed by amphiphilic compounds above their critical micelle concentration in aqueous solution have a narrow size distribution and are dynamic, because there is a fast exchange of amphiphiles in solution and those incorporated in micelles. However, micelles are defined as self-assembled structures, since the structure is in thermodynamical equilibrium. 

Here we consider aggregation in a physically realizable chaotic flow, the journal bearing flow or the vortex mixing flow described earlier. The computations mimic fast coagulation particles seeded in the flow are convected passively and aggregate upon contact. In this example the clusters retain a spherical structure and the capture radius is independent of the cluster size. 

At pH 5.3 and at low salt concentrations polymer addition has practically no influence on the aggregation and on the sedimentation behaviour. At pH 2.3 and at the highest salt concentration (0.1 m) the polymer addition results in infinite absorbances immediately after mixing these reduce to very small absorbances E., and E, - within a short time. This behaviour is attributed to the significant flocculation and the very fast sedimentation of the flocculated particles. 

The metal pnictides discussed earlier are much more strongly aggregated than those of their monometalated analogues. The latter represent highly flexible systems in solution that undergo fast ion-pair separation processes (2). The multinuclear NMR spectra of the... 

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