Effect of aggregates

Both aggregation inefficiency (Adler, 1981) and particle disruption (Hartel and Randolph, 1986) increase with particle size. These dispersive processes can counteract the positive effect of aggregation thereby imposing agglomerate particle size limitations and may give rise to apparent size-independence. 

Besides the experimental data mentioned above, the kinetic dependencies of oxide adsorption of various metals are also of great interest. These dependencies have been evaluated on the basis of the variation of sensitive element (film of zinc oxide) conductivity using tiie sensor method. The deduced dependencies and their experimental verification proved that for small occupation of the film surface by metal atoms the Boltzman statistics can be used to perform calculations concerning conductivity electrons of semiconductors, disregarding the surface charge effect as well as the effect of aggregation of adsorbed atoms in theoretical description of adsorption and ionization of adsorbed metal atoms. Considering the equilibrium vapour method, the study [32] shows that... 

R. H. Schmidt, I. A. Kinloch, A. N. Burgess, A. H. Windle, The effect of aggregation on the electrical conductivity of spin-coated polymer/carbon nanotube composite films, Langmuir, vol. 23, pp. 5707-5712, 2007. 

The effect of aggregation of the subsurface solid phase on kerosene volatilization was studied by Fine and Yaron (1993), who compared the rate of aggregation in two size fractions of a vertisol soil the <1 mm fraction and 2 mm aggregates. The total porosity of these two fractions was similar (53% and 55% of the total volume, respectively). Differences in aggregation are reflected in the air permeability that is, their respective values were 0.0812 0.009 cm and 0.145 0.011 cm Figure 8.10 presents the volatilization of kerosene as affected by the soil aggregation, when the initial amount applied was equivalent to the retention capacity. The more permeable fraction releases kerosene faster and thus enhances volatilization. 

Effects of Aggregation and Solvent Quality on the Viscosity of Semidilute Poly(vinylbutyral)... 

This study addresses two questions 1) Is polymer aggregation in solutions directly related to solvent quality 2) If not, does solvent quality exert an effect on the viscosity of semidilute solutions separate from the effect of aggregation The copolymer poly(vinylbutyral) (PVB) was chosen for this investigation. PVB is known to aggregate in several solvents (IS). Light scattering and intrinsic viscosity measurements were used to assess solvent quality. Viscosities were measured at one concentration in three solvents and temperatures from 25 to 55 C. 

Intrinsic Viscosity. Due to the complicating effects of aggregation and selective adsorption on the A2 values determined by light scattering, another means was sought to characterize the quality of solvents for PVB. The alternate means chosen was intrinsic viscosity measurements. Theory relates the intrinsic viscosity to the polymer chain dimensions through the expression (24)... 

Figure 5.55 Effect of aggregate size on compressive strength of concrete. Reprinted, by permission, from S. Somayaji, Civil Engineering Materials, 2nd ed., p. 127. Copyright 2001 by Prentice-Hall, Inc.

Hill, A.V. (1910) The possible effects of aggregation of the molecules of haemoglobin on its dissociation curves, Journal of Physiology - London 40, IV-VII. 

The effect of aggregation or interchain interaction on the triplet excited state in Pt-acetylide polymers was investigated by comparing the optical properties of 1 with the pentiptycene-bridged polymer 15.21 The interchain interaction is prevented by the sterically demanding pentiptycene moiety in 15, and its photophysics is being dominated by the intrachain triplet exciton. 

Effect of Aggregate Formation upon Electronic Energy Levels of Cyanine Dyes... 

The importance of the factor is of interest this is an adjustable parameter for each solvent, considered by Wilke and Chang to account for the aggregation of the solvent molecules. In fact, it is likely that the effect of aggregation (mutual association of solvent molecules) has, in fact, already been accounted for in the viscosity term r B. So what is the significance of the value In their data set, for the classes sugar , acid and small , water is usually the solvent, which has greater than 1. Therefore the value artificially increases the predicted D, which would otherwise be predicted too small (and appears to make physical sense only if it is considered as a correction to the viscosity term). 

This parameter shows a linear relationship with the creaming rate if the effect of aggregation of the globules is excluded (Riiegg and Blanc, 1981) it can be seen that larger globules in particular affect H, and thus the creaming rate. 

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