Author: George Edward Charles
Publisher:
ISBN:
Category :
Languages : en
Pages :
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"The coalescence of liquid drops at a flat liquid/liquid interface was investigated. Theoretical equations describing the rate of thinning of thin fluid films were derived and their limitations discussed. The influence of temperature, drop size and diffusion on drop stability was determined. " --
Author: Eliza Marie Honey
Publisher:
ISBN:
Category :
Languages : en
Pages : 158
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Author: W. D Weatherford (Jr)
Publisher:
ISBN:
Category :
Languages : en
Pages : 64
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As part of a research and development program on fuel handling and decontamination, a study is being conducted to develop a better understanding of the basic phenomena involved in filter-separator operation. This study has led to the development of a new analytical model of coalescence processes. The model is based upon considerations of the dynamics of molecular processes in the vicinity of interfaces (either liquid-liquid or liquid-solid) and includes film-drainage as well as interface-coalescence phenomena. Experimental studies included the use of selected additives in either the aqueous drops and bulk phase or in the hydrocarbon continuous medium, or both. Liquid-liquid interfacial tension was varied from less than 10 to greater than 50 dynes/cm; viscosity of the hydrocarbon phase was varied from less than 1 to greater than 200 centistokes; and the average coalescence time ranged from less than 1 to greater than 300 seconds. The experimentally measured coalescence times and initial rates of contact angle decay have been correlated successfully in terms of the analytical model. (Author).
Author: Hamarz Aryafar
Publisher:
ISBN:
Category :
Languages : en
Pages : 274
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Author: Zhou Liu
Publisher:
ISBN: 9781361039878
Category :
Languages : en
Pages :
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This dissertation, "Electro-driven Interfacial Phenomena of Droplets, Emulsions and Liquid Marbles" by Zhou, Liu, 刘洲, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: The interplay of electric stress and surface tension enriches the interfacial phenomena of droplets, emulsions and liquid marbles. In this thesis, we mainly focus on how the electric stress affects the generation, coalescence/non-coalescence and mixing of liquid droplets as well as liquid droplets with stabilizers. By exploring the science behind these phenomena, we have also extended some approaches to characterize the robustness/ stability of the emulsions and liquid marbles. Chapter 2 focuses on the phenomena of liquid/liquid interfaces in response to an electric field. We studied the dynamics of two pinned droplets under the influence of an applied electric stress. We found that a sufficiently strong field can induce the contact of droplets, leading to three types of droplets behaviors: "coalescence," "fuse-and-split" and "periodic non-coalescence." We characterized these dynamic regimes in a phase diagram and explored the physics behind them. This work provides the rationale for understanding the interplay between surface tension and electric stresses that governs the behavior of charged droplets. In chapter 3, we studied the responses of surfactant-stabilized liquid/liquid interfaces to a DC/AC electric field. We found that two contacting droplets stabilized by surfactants can be forced to coalesce upon a critical DC voltage. The critical voltage changes with the type, concentration of surfactants and temperature. Based on this, we devised an approach to probe the threshold disjoining pressure which can help predict the emulsion stability quantitatively. In an AC electric field, we found a critical frequency below which the surfactants-stabilized droplets coalesce immediately. Such critical frequency is highly sensitive to the amplitude of the AC voltage, viscosity of the fluids, concentration and nature of the surfactants. In chapter 4, we studied the generation of liquid droplets utilizing an electric stress; this is a study of liquid/air interface in an electric field. We developed a robust and reliable approach to fabricate multi-compartment particles by combining the microfluidic nozzles with the electrospray ionization. The multi-compartment particles fabricated using this technique can be applied for various applications. For instance, by encapsulating different types of cells, or biological cell factors in each compartment of the particles, our particles can be potentially used for cell studies and co-culture of different cells. In chapter 5, we studied the liquid/air interface stabilized by particles. We focused on the mechanical robustness, electro-coalescence and electro-mixing of the liquid marbles. We first devised a new approach to measure a critical pressure for characterizing the robustness of liquid marbles. Using this technique, we systematically investigated the effect of type and size of stabilizing particles as well as the chemical nature of the liquid droplet on the robustness of liquid marbles. Moreover, we found that a chain of liquid marbles can be forced to coalesce when charged by a sufficiently large voltage. Also, following the electro-coalescence, the electric stress can induce a strong convective flow which can mix the fluids in liquid marbles rapidly and efficiently. Our approach based on electro-assisted manipulation of liquids marbles is especially useful for chemical and biomedical reactions involving multiple reagents and steps. DOI:
Author: Laurence R. Weatherley
Publisher: Cambridge University Press
ISBN: 1108421016
Category : Mathematics
Languages : en
Pages : 379
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Book Description
Explore and review novel techniques for intensifying transport and reaction in liquid-liquid and related systems with this essential toolkit. Topics include discussion of the principles of process intensification, the nexus between process intensification and sustainable engineering, and the fundamentals of liquid-liquid contacting, from an expert with over forty-five years' experience in the field. Providing promising directions for investment and for new research in process intensification, in addition to a unique review of the fundamentals of the topic, this book is the perfect guide for senior undergraduate students, graduate students, developers, and research staff in chemical engineering and biochemical engineering.
Author: Teng Dong
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Tharwat F. Tadros
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110386348
Category : Science
Languages : en
Pages : 473
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Book Description
The main objective of this volume is to demonstrate the importance of the fundamental aspects of interfacial phenomena in various industrial applications. The text provides the reader with the knowledge that is essential for the composition of the complex multi-phase systems used in the above mentioned areas of application. It should enable the physical and formulation chemist as well as the chemical engineer in designing the formulation on the basis of a rational approach. It will also enable the formulation scientist to better understanding the factors responsible for producing a stable product with optimum application conditions. The book should also be very useful for teaching the subject of formulation at academic institutions.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Stefan Karpitschka
Publisher:
ISBN:
Category :
Languages : en
Pages : 135
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