Effect of Surface-Active Agents

See also Sections IJIA and 11IB for the effect of surface-active agents on bubble velocity. 

III. Effect of Surface-Active Agents A. Experimental Studies... 

O. B. Kutergin, V. P. Melnikov, and A. N. Nesterov. Effect of surface-active agents on the mechanism and kinetics of hydrate formation of gases. Dokl Akad Nauk Sssr, 323(3) 549-553, 1992. 

M Gibaldi, S Feldman, ND Weiner. Hydrodynamics and diffusional considerations in assessing the effects of surface active agents on the dissolution rate of drugs. Chem Pharm Bull 18 715-723, 1970. 

M. Gibaldi, S. Feldman, N. D. Weiner. Hydrodynamic and diffu-sional considerations in assessing effects of surface active agents on the... 

There are no solutions for transfer with the generality of the Hadamard-Rybczynski solution for fluid motion. If resistance within the particle is important, solute accumulation makes mass transfer a transient process. Only approximate solutions are available for this situation with internal and external mass transfer resistances included. The following sections consider the resistance in each phase separately, beginning with steady-state transfer in the continuous phase. Section B contains a brief discussion of unsteady mass transfer in the continuous phase under conditions of steady fluid motion. The resistance within the particle is then considered and methods for approximating the overall resistance are presented. Finally, the effect of surface-active agents on external and internal resistance is discussed. 

The effects of surface-active agents on the motion of and transfer from bubbles and drops have been discussed in earlier chapters. The main effect is to reduce the mobility of all or part of the interface. In this section we consider briefly two other interfacial phenomena interfacial convection during mass transfer and interfacial barriers to mass transfer. 

One set of observations exists for the effect of surface-active agents on A Tc and The values are somewhat incomplete because the A Tc for pure water could not be obtained with the equipment used. The accompanying table summarizes the results (M9). The results indicate that a decrease in a causes a decrease in the maximum heat flux. Addi-... 

Mel nikova (Ref 6) investigated the effect of surface active agents on the physicochemical and explosive properties of Igdanit. To Insure full utilization of the expl props of Igdanit, the Diesel oil. must be uniformly distributed on granules or crysts of AN. 

Hwang H J, Stenstrom M K (1979) Effects of surface active agents on oxygen transfer, Water Resources Program Report 79-2, University of California Los Angeles. 

Okamura, S., K. Katagiri and Y. Takemoto Effect of surface-active agents in the polymerization of acrylonitrile. J. Chem. Soc. Japan, Ind. Chem. Sect. 61, 241-243 (1958). 

Takahashi, M., Aizawa, M., Miyazawa, K., and Machida, Y., Effects of surface active agents on stratum corneum cell cohesion, J. Soc. Cosmet. Chem., 38, 21, 1987. 

Examination of the relevant theory indicates that the adjuvant effect of surface-active agents on herbicide action is maximized when the quantity FI = yL cos 0, or the film pressure at the liquid/solid interface, has a maximum value. Measurement of surface tension of 1.0% aqueous solutions and of contact angle on a number of substrates (Teflon, paraffin) and plant-leaf surfaces (soybean, com) as a function of hydrophile-lipophile balance show at least one maximum, and these values are in good agreement with earlier experimental data on herbicidal activity. 

It thus appears that the adjuvant effect of surface-active agents on herbicidal activity can be explained in terms of the surface-chemical interactions between the droplet of herbicide solution and the plant-leaf surface. Although, as we have seen, capillary penetration is one aspect of... 

Thome, K.E., Eriksson, G. 1973. The foaming properties of cream. 2. The effects of surface active agents, especially phospholipids and lipoprotein, on the whippabilty of cream. 

In bubble columns, the estimation of parameters is more difficult than in the case of either gas-solid or solid-liquid fluidized beds. Major uncertainties in the case of bubble columns are due to the essential differences between solid particles and gas bubbles. The solid particles are rigid, and hence the solid-hquid (or gas-solid) interface is nondeformable, whereas the bubbles cannot be considered as rigid and the gas-liquid interface is deformable. Further, the effect of surface active agents is much more pronounced in the case of gas-liquid interfaces. This leads to uncertainties in the prediction of all the major parameters such as terminal bubble rise velocity, the relation between bubble diameter and terminal bubble rise velocity, and the relation between hindered rise velocity and terminal rise velocity. The estimation procedure for these parameters is reviewed next. 

Michaels, A.S. Colville, A.R., Jr. The effect of surface active agents on crystal growth rate and crystal habit. J. Phys. Chem. 1960, 64, 13-19. 

Russ) CA 70, ll676ly (1969) (Effect of surface active agents on the physicochemical props of Igdanit)... 

Table I. Reported Effects of Surface-Active Agents on Microbial Degradation...

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