Complex Fluids Commons^™

Coulombic And Non-Coulombic Effects Of Single And Overlapping Electric Double Layers With Surface Charge Regulation, Raviteja Vangara

Chemical and Biological Engineering ETDs

The physical origin of charged interfaces involving electrolyte solutions is in the thermodynamic equilibrium between the surface reactive groups and certain dissolved ionic species in the bulk. This equilibrium is very strongly dependent on the precise local density of these species, also known as potential determining ions in the solution. The latter, however, is determined by the overall solution structure, which is dominated by the large number of solvent molecules relative to all solutes. Hence, the solvent contribution to the molecular structure is a crucial factor that determines the properties of electric double layers. Models that explicitly account for the …

Effect Of Different Types Of Static Mixer Geometry On Quality Of Microbubble Generation, Tee Wu Yang

Student Works (2020-2029)

This research project is mainly focused on the impact of different types of static mixer on the quality of microbubble generation. The design of the microbubble generation consists of venturi to allow the air intake by using pressure difference and then different static mixer geometry are tested to investigate the effect on bubble rising time and dissolved oxygen (DO). At the first part of study, the work comprises of the relationship of bubble rising time at different pressures and bubble diameter at different pressures. It has proved that higher pressure will induce small bubble diameter and the bubble rising time …

Non-Invasive Detection And Assessment Of Coronary Stenosis From Blood Mean Residence Times., Javad Hashemi

Electronic Theses and Dissertations

Coronary artery stenosis is an abnormal narrowing of a coronary artery caused by an atherosclerotic lesion that reduces lumen space. Fractional flow reserve (FFR) is the gold standard method to determine the severity of coronary stenosis based on the determination of rest and hyperemic pressure fields, but requires an invasive medical procedure. Normal FFR is 1.0 and FFR RT, to account for varying volume and flow rate of individual segments. Blood_RT was computed in 100 patients who had undergone the pressure-wire FFR procedure, and a threshold for Blood_RT was determined to assess the physiological significance of a stenosis, …

Stabilization Of Bimodal Colloidal Systems Via Nanoparticle Haloing In Microgravity., Luke Hawtrey

Electronic Theses and Dissertations

Colloidal suspensions typically contain a multi-phase system of solid particles suspended in a liquid medium. Colloids are widely used in industrial applications such as inks, paints, motor oils, foods, cosmetics, and many more. Colloidal systems are typically formed by the interaction of the attractive van der Waals forces and one or more repulsive forces. These repulsive forces include electrostatic repulsion, steric hindrance, and nanoparticle haloing. Nanoparticle Haloing (NPH) is a phenomenon discovered in 2001 as a viable method to stabilize colloidal systems of uncharged silica microparticles using highly charged zirconia nanoparticles. For this thesis the effects of NPH were tested …

Applications Of Ionic Liquids In Membrane Separation, Mohanad Kamaz

Graduate Theses and Dissertations

Ionic liquids represent an emerging attractive material in membrane technology. The central theme of this doctoral dissertation is to develope novel membranes using ionic liquids. Two different approaches were used to prepare ionic liquid membranes including the immobilization of ionic liquid within the membrane pores or the use of pressure assembly method to deposit a selective ionic liquid layer on the top membrane surface.

In chapter 2, imidazolium ionic liquids with three different alkyl halides were successfully synthesized and used to prepare supported ionic liquid membranes (SILMs). SILMs preraper were tested for aqueous and nonaqueous applications. For nonaqueous applications, the …

Covalent Organic Frameworks For The Capture, Fixation, Or Reduction Of Co2, John Ozdemir, Imann Mosleh, Mojtaba Abolhassani, Lauren F. Greenlee, Robert T. Beitle Jr., M. Hassan Beyzavi

Chemical Engineering Faculty Publications and Presentations

Covalent organic frameworks (COFs) are porous crystalline organic polymers which have been the subject of immense research interest in the past 10 years. COF materials are synthesized by the covalent linkage of organic molecules bonded in a repeating fashion to form a porous crystal that is ideal for gas adsorption and storage. Chemists have strategically designed COFs for the purpose of heterogeneous catalysis of gaseous reactants. Presented in this critical review are efforts toward developing COFs for the sequestration of CO2 from the atmosphere. Researchers have determined the CO2 adsorption capabilities of several COFs is competitive with the highest surface …

Spatial Positioning And Operating Parameters Of A Rotary Bell Sprayer: 3d Mapping Of Droplet Size Distributions, Adnan Darwish Ahmad, Binit B. Singh, Mark Doerre, Ahmad M. Abubaker, Masoud Arabghahestani, Ahmad A. Salaimeh, Nelson K. Akafuah

Institute of Research for Technology Development Faculty Publications

In this study, we evaluated the fundamental physical behavior during droplet formation and flow from a rotary bell spray in the absence of an electrostatic field. The impact of a wide range of operating parameters of the rotary bell sprayer, such as flow rates, rotational speeds, and spatial positioning, on droplet sizes and size distributions using a three-dimensional (3-D) mapping was studied. The results showed that increasing the rotational speed caused the Sauter mean diameter of the droplets to decrease while increasing flow rate increased the droplet sizes. The rotational speed effect, however, was dominant compared to the effect of …

Effect Of Surfactant, Oil:Water Ratio And Temperature On The Rheology Of Emulsion-Suspension Complex Fluids: Implications For Oil-Based Drilling Fluids, Gilles Landry Numkam

LSU Doctoral Dissertations

Drilling fluids are non-Newtonian mixtures that play a critical role in the timely and successful completion of oil and gas wells. In the particular case of offshore operations, proper design of drilling fluids is of paramount importance in the constant quest to lower break-even prices. Most downhole problems are directly or in-directly related to the rheological and physical properties of drilling fluids, thereby calling for a better understanding of the underlying changes of these properties with respect to drilling fluid composition and external conditions.

The current stance in the design of drilling fluids involves the selection of components and their …

Phase Rule Classification Of Physical And Chemical Critical Effects In Liquid Mixtures, James K. Baird, Xingjian Wang, Joshua R. Lang, Pauline Norris

PRC-Affiliated Research

The isobaric heat capacity and the coefficient of thermal expansion of a binary liquid mixture with a critical point of solution diverge as functions of temperature in the critical region. When the same liquids are used as solvents for chemical reactions, the van't Hoff plot of the extent of reaction diverges in the critical region. According to the phase rule, the physical and chemical properties are isomorphic in the sense that in each case the critical behavior is determined by three fixed thermodynamic intensive variables.

Phase Rule Classification Of Physical And Chemical Critical Effects In Liquid Mixtures, James K. Baird, Xingjian Wang, Joshua R. Lang, Pauline Norris

PRC-Affiliated Research

The isobaric heat capacity and the coefficient of thermal expansion of a binary liquid mixture with a critical point of solution diverge as functions of temperature in the critical region. When the same liquids are used as solvents for chemical reactions, the van't Hoff plot of the extent of reaction diverges in the critical region. According to the phase rule, the physical and chemical properties are isomorphic in the sense that in each case the critical behavior is determined by three fixed thermodynamic intensive variables.

Phase Rule Classification Of Physical And Chemical Critical Effects In Liquid Mixtures, James K. Baird, Xingjian Wang, Joshua R. Lang, Pauline Norris

PRC-Affiliated Research

The isobaric heat capacity and the coefficient of thermal expansion of a binary liquid mixture with a critical point of solution diverge as functions of temperature in the critical region. When the same liquids are used as solvents for chemical reactions, the van't Hoff plot of the extent of reaction diverges in the critical region. According to the phase rule, the physical and chemical properties are isomorphic in the sense that in each case the critical behavior is determined by three fixed thermodynamic intensive variables.

Multiphase Cfd Modeling In Particle-Laden Flows, Zhizhong Ding

LSU Doctoral Dissertations

Multiphase modeling is prevalent and useful in solving problems involving multiphase interactions such as fluid and solid. Applications conclude but not limited to fluidized bed, hydraulic conveying, and many others. Modeling techniques with multiple scales can provide various states of details with diverse computational resources used. In this dissertation, two CFD multiphase models are used to disclose interaction details in the particulate system. Two-Fluid Model is used to solve pulsed fluidized bed problem and immersed boundary method based direct numerical method is used to solve particle’s behavior in shear flow. Getting a better understanding of these problems to help to …

Fluid Flow Analysis Of Diluted Evaporating American Whiskey Droplets., Martin J. Brown Vi

Electronic Theses and Dissertations

The recent discovery of the unique structures, whiskey webs, formed when the evaporation of diluted American whiskey, has raised many questions as to the nature of the structures. Their formation process follows as such: (1) dilution of the whiskey to form nanoaggregates, (2) formation of a monolayer at the air-liquid interface, (3) chaotic ethanol evaporation caused monolayer collapse (via dynamic pressure), (4) bulk fluid evaporation caused monolayer collapse (via reduction of surface area), where the web-like structures reside on the surface, and finally, (5) web-like structures deposit on the substrate. The webs imaged via SEM had a striking resemblance to …

The Synthesis, Purification, And Characterization Of The P3 Peptoid, Myles Joyce

Chemical Engineering Undergraduate Honors Theses

The relatively young field of nano-systems has vast applications over various different fields. Peptoids (peptide analogues) and their uses are consistently investigated components of these nano-studies. A particularly interesting group of peptoids are able to self-assemble into secondary structures under the right conditions. The P3 peptoid is able to form microspheres if properly synthesized and purified. Microspheres are frequently studied due to their low surface area to volume ratios. This unique aspect of microspheres makes them an excellent candidate for drug delivery systems; however, these systems must also be robust so that the desired compound can be encapsulated within the …

Exploring The Role And Impact Of Microscale Phenomena On Electrode, Microdevice, And Cellular Function, Sanaz Habibi

Dissertations, Master's Theses and Master's Reports

Microfluidic technologies enable the development of portable devices to perform multiple high-resolution unit operations with small sample and reagent volumes, low fabrication cost, facile operation, and quick response times. Microfluidic platforms are expected to effectively interpret both wanted and unwanted phenomena; however, a comprehensive evaluation of the unwanted phenomena has not been appropriately investigated in the literature. This work explored an attenuative evaluation of unwanted phenomena, also called here as secondary phenomena, in a unique approach.

Upon electric field utilization within microfluidic devices, electrode miniaturization improves device sensitivity. However, electrodes in contact with medium solution can yield byproducts that can …

Microfluidic Study Of Gravity-Driven Drainage And Coalescence Of Aqueous Two Dimensional Foams, Justin D. Heftel

Dissertations and Theses

Foams, a two-phase dispersion, are staples of the cosmetic, personal care, petroleum, pharmaceutical, and other industries. Central to these applications is the stability of the dispersion against separation. Foams break down by two mechanisms: the first is bubble coalescence, which is driven by the gravity drainage of the continuous phase. The drainage acts to push the bubbles against each other, and leads to the formation of thin lamellae, which break and cause the coalescence. The second is the mass transfer of the dispersed phase through the continuous phase, which is caused by the difference in pressures between the bubbles and …