Diffusion internal viscosity effect

The effect of hydrodynamic interaction of particles on the factor of mutual diffusion of particles has been studied in paper [22]. It formulated a theoretical basis for the determination of collision frequency of particles in a turbulent flow. The effect of internal viscosity of drops on their collision frequency was studied in [23-26]. It was shown that the correct accounting for hydrodynamic interaction ensures a good agreement between the theory and the experiment. 

Fig. 8. Dependence of (A) corrected diffusion coefficient (D), (B) steady-state fluorescence intensity, and (C) corrected number of particles in the observation volume (N) of Alexa488-coupled IFABP with urea concentration. The diffusion coefficient and number of particles data shown here are corrected for the effect of viscosity and refractive indices of the urea solutions as described in text. For steady-state fluorescence data the protein was excited at 488 nm using a PTI Alphascan fluorometer (Photon Technology International, South Brunswick, New Jersey). Emission spectra at different urea concentrations were recorded between 500 and 600 nm. A baseline control containing only buffer was subtracted from each spectrum. The area of the corrected spectrum was then plotted against denaturant concentrations to obtain the unfolding transition of the protein. Urea data monitored by steady-state fluorescence were fitted to a simple two-state model. Other experimental conditions are the same as in Figure 6.

The second part of the chapter is devoted to the effect of pressure on heat and mass transfer. After a brief survey on fundamentals the estimation of viscosity, diffusivity in dense gases, thermal conductivity and surface tension is explained. The application of these data to calculate heat transfer in different arrangements and external as well as internal mass transfer coefficients is shown. Problems at the end of the two main parts of this chapter illustrate the numerical application of the formulas and the diagrams. 

On the other hand, the lack of internal pore structure with micropellicular sorbents is of distinct advantage in the analytical HPLC of biological macromolecules because undesirable steric effects can significantly reduce the efficiency of columns packed with porous sorbents and also result in poor recovery. Furthermore, the micropellicular stationary phases which have a solid, fluid-impervious core, are generally more stable at elevated temperature than conventional porous supports. At elevated column temperature the viscosity of the mobile phase decreases with concomitant increase in solute diffusivity and improvement of sorption kinetics. From these considerations, it follows that columns packed with micropellicular stationary phases offer the possibility of significant improvements in the speed and column efficiency in the analysis of proteins, peptides and other biopolymers over those obtained with conventional porous stationary phases. In this paper, we describe selected examples for the use of micropellicular reversed phase... 

Extraction Rates. The design of large-scale solvent extraction vessels must accommodate the rate at which equilibrium is attained between the free miscella flowing past the solid particles and the miscella absorbed within the solids. Attainment of equilibrium may be quite slow, particularly as the oil content of the solid material drops to low levels. Investigations show that the rate at which equilibrium is approached (in effect, the extraction rate) is influenced by many factors, including the intrinsic capacity for diffusion of solvent and oil, which is determined primarily by the viscosities of the two the size, the shape, and the internal structure of the solid particles and, at low oil levels in the solids, the rate at which the solvent dissolves nontriglyceride substances that are soluble but dissolve less readily than the triglycerides. 

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