scholarly journals Effect of the hydrophobic phase on interfacial phenomena of surfactants, proteins, and particles at fluid interfaces

2021 ◽  
pp. 101509
Author(s):  
Jotam Bergfreund ◽  
Pascal Bertsch ◽  
Peter Fischer
Keyword(s):  
Interfacial Phenomena ◽  
Fluid Interfaces

A Laboratory Device to Measure the Interfacial Phenomena between Rubber and Rough Surfaces

1999 ◽  
Vol 27 (4) ◽  
pp. 206-226 ◽  
Author(s):  
L. Garro ◽  
G. Gurnari ◽  
G. Nicoletto ◽  
A. Serra
Keyword(s):  
Rough Surfaces ◽  
Computer Software ◽  
Interfacial Phenomena ◽  
New Device ◽  
The Road ◽  
Constant Torque ◽  
Rubber Compounds ◽  
Simple Geometry ◽  
Tangential Forces ◽  
On The Road

Abstract The interfacial phenomena between tread rubber compounds and rough surfaces are responsible for most of the behavior of a tire on the road. A new device was developed for the investigation of these phenomena in the laboratory. The device consists of a fully instrumented road wheel on which a simple geometry specimen is driven. The possibilities offered by this device are to perform tests at constant slip or at constant torque on both wet and dry surfaces, with complex cycles. The machine allows the measurement of slip, tangential forces, and temperature on the specimen, and computer software adds the possibility of applying Fourier analyses on force, road wheel speed, and specimen speed data. Other possibilities offered by the road wheel are to change the road surface, the load on the specimen, and the water rate. The description of a complete experiment is detailed in the paper showing the correlation of data with actual tire performances.

Soft Interfaces

2017 ◽  
Keyword(s):  
Soft Matter ◽  
Capillary Forces ◽  
Soft Material ◽  
Interfacial Phenomena ◽  
Adhesive Tape ◽  
Soft Interfaces ◽  
Lecture Notes ◽  
Lecture Courses

Many of the distinctive and useful phenomena of soft matter come from its interaction with interfaces. Examples are the peeling of a strip of adhesive tape or the coating of a surface or the curling of a fibre via capillary forces or the electrically driven ow along a microchannel, or the collapse of a porous sponge. These interfacial phenomena are distinct from the intrinsic behaviour of a soft material like a gel or a microemulsion. Yet many forms of interfacial phenomena can be understood via common principles valid for many forms of soft matter. Our goal in organizing this school was to give students a grasp of these common principles and their many ramifications and possibilities. The school comprised over fifty 90-minute lectures over four weeks in July 2013. Four four-lecture courses by Howard Stone, Michael Cates, David Nelson, and L. Mahadevan served as an anchor for the program. A number of shorter courses and seminars rounded out the school.This volume presents lecture notes prepared by the speakers and submitted for publication after the school. The lectures are grouped under two main themes: Hydrodynamics and interfaces, and Soft matter.

scholarly journals Surfactant Adsorption to Different Fluid Interfaces

Langmuir ◽  
2021 ◽  
Author(s):  
Jotam Bergfreund ◽  
Sarina Siegenthaler ◽  
Viviane Lutz-Bueno ◽  
Pascal Bertsch ◽  
Peter Fischer
Keyword(s):  
Fluid Interfaces ◽  
Surfactant Adsorption

scholarly journals Proteins from microalgae for the stabilization of fluid interfaces, emulsions, and foams

2021 ◽  
Vol 108 ◽  
pp. 326-342
Author(s):  
Pascal Bertsch ◽  
Lukas Böcker ◽  
Alexander Mathys ◽  
Peter Fischer
Keyword(s):  
Fluid Interfaces

scholarly journals β-Lactoglobulin Adsorption Layers at the Water/Air Surface: 5. Adsorption Isotherm and Equation of State Revisited, Impact of pH

2021 ◽  
Vol 5 (1) ◽  
pp. 14
Author(s):  
Georgi G. Gochev ◽  
Volodymyr I. Kovalchuk ◽  
Eugene V. Aksenenko ◽  
Valentin B. Fainerman ◽  
Reinhard Miller
Keyword(s):  
Theoretical Description ◽  
Fluid Interfaces ◽  
Interfacial Behavior ◽  
Current State ◽  
Air Interface ◽  
Direct Measurements ◽  
Wide Range ◽  
Dilational Viscoelasticity ◽  
Parameter Values ◽  
Β Lactoglobulin

The theoretical description of the adsorption of proteins at liquid/fluid interfaces suffers from the inapplicability of classical formalisms, which soundly calls for the development of more complicated adsorption models. A Frumkin-type thermodynamic 2-d solution model that accounts for nonidealities of interface enthalpy and entropy was proposed about two decades ago and has been continuously developed in the course of comparisons with experimental data. In a previous paper we investigated the adsorption of the globular protein β-lactoglobulin at the water/air interface and used such a model to analyze the experimental isotherms of the surface pressure, Π(c), and the frequency-, f-, dependent surface dilational viscoelasticity modulus, E(c)f, in a wide range of protein concentrations, c, and at pH 7. However, the best fit between theory and experiment proposed in that paper appeared incompatible with new data on the surface excess, Γ, obtained from direct measurements with neutron reflectometry. Therefore, in this work, the same model is simultaneously applied to a larger set of experimental dependences, e.g., Π(c), Γ(c), E(Π)f, etc., with E-values measured strictly in the linear viscoelasticity regime. Despite this ambitious complication, a best global fit was elaborated using a single set of parameter values, which well describes all experimental dependencies, thus corroborating the validity of the chosen thermodynamic model. Furthermore, we applied the model in the same manner to experimental results obtained at pH 3 and pH 5 in order to explain the well-pronounced effect of pH on the interfacial behavior of β-lactoglobulin. The results revealed that the propensity of β-lactoglobulin globules to unfold upon adsorption and stretch at the interface decreases in the order pH 3 > pH 7 > pH 5, i.e., with decreasing protein net charge. Finally, we discuss advantages and limitations in the current state of the model.

scholarly journals Interfacial Phenomena and Inclusion Formation Behavior at Early Melting Stages of HCFeCr and LCFeCr Alloys in Liquid Iron

2021 ◽  
Author(s):  
Yong Wang ◽  
Andrey Karasev ◽  
Joo Hyun Park ◽  
Wangzhong Mu ◽  
Pär G. Jönsson
Keyword(s):  
Liquid Iron ◽  
Diffusion Zone ◽  
Early Stage ◽  
Interfacial Phenomena ◽  
Solid Alloy ◽  
Low Carbon ◽  
High Carbon ◽  
Free Zone ◽  
Formation Behavior ◽  
Predetermined Time

AbstractChromium is normally added to liquid alloy in the form of different grades of ferrochromium (FeCr) alloys for the requirement of different alloy grades, such as stainless steels, high Cr cast iron, etc.. In this work, inclusions in two commercially produced alloys, i.e., high-carbon ferrochromium (HCFeCr) and low-carbon ferrochromium (LCFeCr) alloys, were investigated. The FeCr alloy/liquid iron interactions at an early stage were investigated by inserting solid alloy piece into contact with the liquid iron for a predetermined time using the liquid-metal-suction method. After quenching these samples, a diffusion zone between the alloys and the liquid Fe was studied based on the microstructural characterizations. It was observed that Cr-O-(Fe) inclusions were formed in the diffusion zone, FeOx inclusions were formed in the bulk Fe, and an “inclusion-free” zone was detected between them. Moreover, it was found that the HCFeCr was slowly dissolved, but LCFeCr alloy was rapidly melted during the experiment. The dissolution and melting behaviors of these two FeCr alloys were compared and the mechanism of the early-stage dissolution process of FeCr alloys in the liquid Fe was proposed.

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