Some Experiments on Detergency in Aqueous and Non-aqueous Media, IX. A Comparison of Laboratory and Machine Tests on the Influence of Surfactant Concentration in Two-Phase (Emulsion) Cleaning

Two-phase flows involving phase change are ubiquitous in a diverse range of scientific and technological applications. There has been great recent interest in the enhancement of boiling heat transfer processes by means of additives such as surfactants. Surfactants can influence boiling through convection currents in the bulk fluids as a result of changes in the surface tension caused by local surfactant concentration due their adsorption/desorption from the bulk regions. This can result in changes in bubble release patterns and higher heat transfer rates if such changes lead to higher rate of vapor formation. We intend to study this effect in the context of film boiling. Our computational approach augments the CLSVOF method with bulk energy and diffusion equations along with a phase change model and an interface surfactant model. The challenge here is to accurately calculate the tangential gradients of the interfacial surfactant concentration in the presence of discontinuous bulk concentration gradients near the interface. We discuss a simplified model in which the interfacial surfactant concentration is always in equilibrium with the changing bulk concentrations and then present validation results to assess the accuracy of this approach. Finally, initial studies of surfactant enhanced film boiling will be presented and interpreted.

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Formation of Cd x Pb1− x S/Cd1- δ S Thin-Film Two-Phase Compositions by Chemical Bath Deposition: Composition, Structure, and Optical Properties

10.21203/rs.3.rs-331744/v1 ◽

2021 ◽

Author(s):

L. N. Maskaeva ◽

I. V. Vaganova ◽

V. F. Markov ◽

V. I. Voronin ◽

O. A. Lipina ◽

...

Keyword(s):

Thin Film ◽

Chemical Bath Deposition ◽

Aqueous Media ◽

Substitutional Solid Solution ◽

Solid Solution Phase ◽

Two Phase ◽

X Ray ◽

Technological Stage ◽

Composition Structure ◽

Cadmium And Lead

Abstract The possibility of forming thin-film two-phase compositions CdxPb1-xS/Cd1-dS by using the chemical bath deposition from aqueous media with adding various cadmium salts has been demonstrated. The crystal structure, chemical composition, morphology, and the band gap were studied by the X-ray diffraction, scanning electron microscopy, elemental analysis, Auger and Raman spectroscopy, and diffuse reflectance measurements. The formation of a CdxPb1-xS/Cd1-dS substitutional solid solution phase in well-faceted crystallites on the substrate of an X-ray amorphous CdS phase has been experimentally proved. The found differences in their composition are the result of the effect of the nucleophilicity of the anionic component of the cadmium salt on the kinetics of thiourea decomposition. The results demonstrate the possibility of forming thin-film two-phase compositions or heterostructures on the base of cadmium and lead sulfides in one technological stage by using chemical bath deposition, which can be important for the creation of solar cells.

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Linear Relationships between Partition Coefficients of Different Organic Compounds and Proteins in Aqueous Two-Phase Systems of Various Polymer and Ionic Compositions

Polymers ◽

10.3390/polym12071452 ◽

2020 ◽

Vol 12 (7) ◽

pp. 1452

Author(s):

Nuno R. da Silva ◽

Luisa A. Ferreira ◽

Pedro P. Madeira ◽

José A. Teixeira ◽

Vladimir N. Uversky ◽

...

Keyword(s):

Organic Compounds ◽

Partition Coefficients ◽

Aqueous Media ◽

Protein S ◽

Distribution Coefficients ◽

Two Phase ◽

Linear Relationships ◽

Aqueous Two Phase Systems ◽

Phase Systems

Analysis of the partition coefficients of small organic compounds and proteins in different aqueous two-phase systems under widely varied ionic compositions shows that logarithms of partition coefficients for any three compounds or proteins or two organic compounds and one protein are linearly interrelated, although for protein(s) there are ionic compositions when the linear fit does not hold. It is suggested that the established interrelationships are due to cooperativity of different types of solute–solvent interactions in aqueous media. This assumption is confirmed by analysis of distribution coefficients of various drugs in octanol-buffer systems with varied ionic compositions of the buffer. Analysis of the partition coefficients characterizing distribution of variety of drugs between blood and different tissues of rats in vivo reported in the literature showed that the above assumption is correct and enabled us to identify the tissues with the components of which the drug(s) may engage in presumably direct interactions. It shows that the suggested assumption is valid for even complex biological systems.

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