Chemical Engineering Commons^™

Simulations Of Interfacial Electrokinetics With Applications To Microfluidic Systems, Sebastian Uppapalli

UNLV Theses, Dissertations, Professional Papers, and Capstones

Electrokinetics plays an important role in facilitating fluid transport and particle manipulation in microfluidic systems. This dissertation studies the mechanics of electrokinetic phenomena for microscale particles and drops. The work aims to increase the understanding of complex electrokinetic phenomena for applications in Lab-on-Chip technology, assembly of colloidal particles and two-phase flow sensing. The standard model consisting of the Poisson-Nernst-Planck equations is used to study the electric double layer polarization of charged dielectric particles and channel wall which plays a major role in control and manipulation of colloidal particles and understanding of electrohydrodynamic flow field.

The cases of polarization of "soft" …

Design Of A Light-Weight Low-Volume High Oxygen Storage Density Material, Nicholas Robert Schwartz

Theses and Dissertations

A compact, lightweight, dense and safe method for storing and supplying oxygen remains a large hurdle for closed-circuit self-contained breathing apparatus (SCBA) and respiratory protective equipment. No filter that can protect against airborne chemical, biological, radiological, and nuclear (CBRN) contaminants exists, which presents the need for an isolated oxygen source. Heavy and high maintenance oxygen cylinders are typically used. The most important criteria for a smart and effective CBRN protection device are safety, weight, size, and cost, level of maintenance, ease-of-use and reliability. This study focused on nanomaterials for high capacity gas storage. Nanocapillary arrays composed of anodic aluminum oxide …

Comparing Virus Ultrafiltration Of Bacteriophages With Filtration Of Minute Virus Of Mice, Kent Smith

Graduate Theses and Dissertations

Industrial production of protein therapeutics demand rigorous testing and clearance of viruses. The U.S. Food and Drug Administration dictate the purity of pharmaceuticals with regards to viral contamination. As this testing is time consuming and expensive using mammalian cells and viruses, bacteriophages may provide a faster and cheaper alternative for membrane filtration processes. We used ultrafiltration membranes to filter protein solutions with viruses. Two bacteriophages were tested against membranes with two different pore sizes. These membranes were then tested by inverting the membrane's orientation. Flux measurements and log virus removal data were taken. Flux and log virus removal were seen …

Density Functional Theory Study Of The Thermodynamics Of Catalytic Remediation Of Nitrate In Water, Lizzie Bollmann

All Theses

Over 1 billion people worldwide lack access to safe drinking water and 5,000 people die each day due to drinking contaminated water. With the development of new industries, new substances and chemicals are entering the waters every day, and the current water treatment processes are unable to remove them entirely. For example, agriculture is the world's heaviest consumer of water, and nitrates and nitrites from fertilizers are washed away with the water to rivers and streams. These chemicals can cause problems to humans and to the environment. To humans, they can cause methemoglobinemia, also known as 'blue baby syndrome'. To …

Outlining The Biocidal Mechanisms Of Synthetic Antimicrobial Peptide Mimics, Tyler D. Brown

Honors Theses

Each day, antibiotic resistance affects the livelihood of individuals worldwide, especially in relation to hospital-acquired diseases. In an effort to combat this resistance, antimicrobial peptides, small biopolymers produced naturally by multicellular organisms, can be used to selectively eliminate bacteria and have demonstrated great potential as alternatives to conventional antibiotics. Many naturally-occurring antimicrobial peptides possess high concentrations of lysine and arginine amino acid residues, which are protonated and positively-charged at physiological pH. Herein, we describe the design and synthesis of antimicrobial peptide mimics, using amino acid mimics. N-3-aminopropyl methacrylamide (APMA) and 3-guanidinopropyl methacrylamide (GPMA) monomers mimic the amino acid residues lysine …

Preparation Of Pt/H-Tio2 Catalyst With Improved Catalytic Performance For Methanol Electrooxidation, Jin Han, Zhi-You Zhou, Qiang Wang, Miao-Qiang Lv, Chi Chen, Shi-Gang Sun

Journal of Electrochemistry

White TiO₂ nanorods were synthesized by hydrothermal method with TiCl₄ as a precursor. As-synthesized TiO₂ nanorods were further subjected to high-temperature (550 ^oC) heat treatment for 2 h under H₂ atmosphere to prepare gray black hydrogen-treated TiO₂ (H-TiO₂) nanorods with oxygen vacancies and Ti³⁺ interstitial atoms. The Pt nanoparticles of 1.9 nm were supported on these two types of TiO₂ nanorods to form Pt/TiO₂ and Pt/H-TiO₂ catalysts. XRD data indicates that the crystal structure of TiO₂ was still reserved as rutile after hydrogen treatment, but the surface …

Electrocatalytic Oxidation Of Glycerol At The Platinum Electrode Modified With An Nd-Fe-Moo42- Cyano-Bridged Mixed Coordination Polymer, Yong-Jun Ma, Yu-Xiu Tian, Jing Liu, Min Zhou, Jing Ding, Zhi-Mei Jin, Xiang-Mei Wang

Journal of Electrochemistry

A platinum electrode decorated with the ordered Nd-Fe-MoO₄^2- cyano-bridged mixed coordination polymer was successfully prepared by electrodeposition in virtue of the lyotropic liquid crystal soft template methods, and electrocatalytic oxidation behavior of glycerol was investigated on the chemically modified electrode by cyclic voltammetry. The influences of experimental factors such as the concentrations of H⁺ and SO₄^2- in electrolytes, glycerol concentration and scan rate on the electrocatalytic activity of glycerol at the modified electrode were also studied. It indicated that the proper amount of SO₄^2- in weakly acidic electrolyte could help to improve the …

Synthesis Of Platinum Nanocrystallites And Possible Electrocatalytic Properties For Methanol, Lei-Lei Lu, Bao-Zhong Du, Sha Sun, Jin-Fen Niu, Jie Zhao

Journal of Electrochemistry

Platinum nanocrystallites were synthesized by the colloidal method using oxamide as the stabilizer. The morphologies and electrocatalytic performances for methanol of platinum nanocrystallites prepared at different pH values and with different reactant ratios of precursor and stabilizer were investigated. It was found that the platinum nanocrystallites synthesized at pH=5 and with the reactant ratio of 1:20 showed the best electrocatalytic activity for methanol. The peak current density reached up to 1709 μA·cm^-2. Furthermore, the electrocatalytic activity of platinum nanocrystallites for methanol reduced significantly although the cyclic voltammograms in the blank solution were not obviously changed after exposing in …

Effect Of Temperature On The Self-Humidifying Open-Cathode Proton Exchange Membrane Fuel Cell, Si-Chen Zhao, Ben Wang, Qiu-Hong Jia, Ming Han, Yu-Hong Xie

Journal of Electrochemistry

Based on the experiments about the output characteristics of a home-made temperature-controlled PEMFC system with atmospheric pressure and no external humidifying condition in different loading voltages and operating temperatures, the optimum operating temperature at different loading voltages can be obtained by tracking the output characteristics of PEMFC operating over a range of temperatures. By analyzing the fitted data the kinetic parameters are evaluated and the effect of different operating temperatures on the PEMFC performance is discussed from a view of electrode kinetics.

Electro-Catalytic Oxidation Of Hydrogen Peroxide On Au/ L-Methionine /Gc Electrode, Jian-Feng Fan, Xue-Mei Luo, Jing Li, Lou-Zhen Fan

Journal of Electrochemistry

The modified electrodes have been fabricated by generation of Au nanoparticle chains, which was produced by reaction between HAuCl4 and sodium citrate without any additional capping agents or surfactants. The self-assembled Au nanoparticles were attached to the surface of glassy carbon electrode (GCE) layer by layer, using L-methionine (L-Met), thiourea (TU), allyl thiourea (ATU) and polyvinylpyrrolidone (PVP) as a crosslinking agent, respectively. The experimental results showed that the electrochemical performance of the different modified electrodes varied in [Fe(CN)₆]^3-/4- solution. The Au/L-Met/GCE exhibited an excellent electrochemical property, which is superior to other modified electrodes. In addition, the catalysis …

Enhancement Of Mass Transfer And Electron Usage For Syngas Fermentation, James J. Orgill

Theses and Dissertations

Biofuel production via fermentation is produced primarily by fermentation of simple sugars. Besides the sugar fermentation route, there exists a promising alternative process that uses syngas (CO, H2, CO2) produced from biomass as building blocks for biofuels. Although syngas fermentation has many benefits, there are several challenges that still need to be addressed in order for syngas fermentation to become a viable process for producing biofuels on a large scale. One challenge is mass transfer limitations due to low solubilities of syngas species. The hollow fiber reactor (HFR) is one type of reactor that has the potential for achieving high …

A Sequential Grid, Relaxation Method For Use In Oil Reservoir Simulation, Brian Stimpson, Dr. Hugh Hales

Journal of Undergraduate Research

The demand for petroleum products has never been higher, despite the opposition and environmental skepticism that has been present against the petroleum industry in recent years. This requires the production of petroleum products to increase. However, as politics and nature will have it, the waning supply of petroleum is becoming ever more difficult to access and tap into. To make sure we are using our reserves in the best possible ways, this industry must adapt, create better technology, and have careful planning and predictions.

Advanced Measuring Techniques Of Ionic And Electronic Conductivities In Battery Electrodes, Joshua Flygare, Dr. Dean Wheeler

Journal of Undergraduate Research

Introduction: There are many significant barriers still to be overcome before chemical storage becomes satisfactory. One of the most significant issues is how much the electrodes vary in their electronic and ionic conductivities. Both of these issues are highly complex. My funding was used to help me learn the basic mathematics and physics that occur inside of batteries. I used this understanding to make two models, one using COMSOL multiphysics, and another cruder model using Excel. The most significant change made in my execution from my original proposal was I used all of my time in understanding and making models, …

Spin Cycle: Hand Powered Washing For Peru, Jared Bruton, Dr. Randy Lewis

Journal of Undergraduate Research

Washing clothes is time consuming and physically difficult for women on the islands of Lake Titicaca. Women fill buckets with water and soap, allow the clothes to soak, rub them together to get the dirt out, and then wring them out. Doing this is physically demanding, especially during the harsh cold of winter. This project develops a human-powered, affordable, and easy to build clothes-washing device that allows women to save time and energy washing clothes. It builds on a similar washing machine project from one year ago, but seeks to reduce the cost of the hand-powered machine from 300 Peruvian …

Kinetic Modeling Of Self-Hydrolysis Of Aqueous Nabh4 Solutions By Model-Based Isoconversional Method, Rajasree Retnamma, A. Q. Novais, C. M. Rangel, Lin Yu, Michael A. Matthews

Faculty Publications

The present work reports the kinetic modeling of self-hydrolysis of non-buffered, non-stabilized NaBH4 solutions by model-based isoconversional method. The overall kinetics is described by a „reaction-order‟ model in a practical operating window of 10-20 wt% NaBH4 solutions at 25-80 C and 0-50% conversions. The apparent activation energy and pre-exponential factor are interrelated through a kinetic compensation effect (KCE). The apparent reaction order remains constant at a given temperature irrespective of extent of conversion and decreases with increase in temperature. It decreases from firstorder to 0.26 with increase in temperature from 25 to 80 C. The apparent activation energy is found …

Evaluation Of Thin Film Nanotube-Antibody Matrix Materials For Potential Integration Into Immunodiagnostic Biosensors, Brian Young

Faculty Research and Creative Activities Award (FRACAA)

Most quantitative immunodiagnostic assay products require large laboratory equipment, controlled lab environments, and highly skilled technicians, making them expensive and impractical for use in other environments such as physician offices, the home and field clinics of developing countries. The long-range goal of this work is to attempt to develop an inexpensive quantitative hand-held immunobiosensor-based technology that can easily be applied to any antibody:antigen combination and used in any setting. A new approach to measure antibody:antigen binding in the presence of nanotubes has been described in several recent studies. Using conductive polymer/nanotube/antibody solution-impregnated filter paper, these researchers showed a change in …

Model Predictive Control With A Rigorous Model Of A Solid Oxide Fuel Cell, Lee T. Jacobsen, Dr. John D. Hedengren

Journal of Undergraduate Research

Degradation of Solid Oxide Fuel Cells (SOFCs) can be minimized by maintaining reliability parameters during load changes. These reliability parameters are critical to maintain power generation efficiency over an extended life of the SOFC. For SOFCs to be commercially viable, the life must exceed 20,000 hours for load following applications. This is not yet achieved because transient stresses damage the fuel cell and degrade the performance over time. This study relates the development of a dynamic model for SOFC systems in order to predict optimal manipulated variable moves along a prediction horizon. The model consists of hundreds of states and …

Development Of Multimodal Membrane Adsorbers For Antibody Purification Using Atom Transfer Radical Polymerization, Juan Wang, Scott M. Husson

Graduate Research and Discovery Symposium (GRADS)

No abstract provided.

Carbon Fibers Derived From Sustainable Precursors, Meng Zhang, Jing Jin, Amod A. Ogale

Chemical and Biomolecular Graduate Research Symposium

No abstract provided.

Producing A Liquid-Lignin Phase From Kraft Black Liquor: Phase Behavior And Structural Characterization, Julian Velez, Mark C. Thies

Chemical and Biomolecular Graduate Research Symposium

No abstract provided.

Density Functional Theory-Based Modeling Of Catalyzed Water Purification, Lizzie Bollman

Chemical and Biomolecular Graduate Research Symposium

No abstract provided.

Effect Of Co Adsorption And Coverage On Ethanol Production From Syngas, Anuradha Gundamaraju, Ming He, David A. Bruce

Graduate Research and Discovery Symposium (GRADS)

In the future, the availability of reliable alternative fuels will be crucial for any country to become energy independent. One such alternative is ethanol as it can be used both as a fuel and as a fuel additive. Most of the ethanol produced in the world today is derived from biomass. The biomass feedstocks and fermentation broths used in ethanol production both contain high amounts of water and therefore, the energy efficiency of the process is lessened by product separation processes (azeotropic separation of water and ethanol) that are non-trivial and highly inefficient (due to the evaporation of water). An …

Template Free-Synthesis Of Polypyrrole Microtubes For Supercapacitor Electrodes, Kryssia P. Diaz, Mark E. Roberts

Graduate Research and Discovery Symposium (GRADS)

The purpose of this work is to develop a simple, scalable and template-free method to synthesize conducting polymer nano/micro-structures for supercapacitor electrodes. The microstructure and electrochemical properties of structure polypyrrole on various mesh substrates is investigated.

Recovering A Liquid-Lignin Phase From Paper Mill Black Liquors, Julian Velez, Adam Klett, Mark C. Thies

Graduate Research and Discovery Symposium (GRADS)

No abstract provided.

Analysis Of Solvation Model, Adsorption Site, And Adsorbate Coverage Effects On Adsorption Energies At The Anode In Direct Methanol Fuel Cells, Cameron J. Bodenschatz, Rachel B. Getman

Graduate Research and Discovery Symposium (GRADS)

No abstract provided.

Synthesis And Characterization Of Extractive Scintillating Resin For Ultra-Trace-Level Quantification Of Uranium In Aqueous Media, C Duval, V Bliznyuk, A Seliman, T Devol, S Husson

Graduate Research and Discovery Symposium (GRADS)

The detection and quantification of radionuclides in aqueous media is of interest to both the Environmental Protection Agency, for matters of public health, and international organizations like the Comprehensive Test Ban Treaty Organization, that use environmental samples to investigate claims of illicit nuclear activities. The current method of quantification involves batch style analytical techniques which utilize bulky instruments. Portable, flow cell detectors utilizing extractive scintillating resin with physically sorbed extractants and fluorophores have been developed; however, this resin shows poor long term stability as the active components leach from the resin over time. There is a need to develop chemically …

Roll-To-Roll Synthesis Of Vertically Aligned Carbon Nanotubes For Electrical Double Layer Capacitors, Margarita R. Arcila-Velez, Jingyi Zhu, Anthony Childress, Mehmet Karakaya, Ramakrishna Podila, Apparao M. Rao, Mark E. Roberts

Graduate Research and Discovery Symposium (GRADS)

No abstract provided.

Effect Of Surface Parameters On Interfacial Water Film Behavior, Brittany Glatz, Luke Rhym, Sapna Sarupria

Graduate Research and Discovery Symposium (GRADS)

Vapor-to-liquid and liquid-to-solid transitions on mineral surfaces are the primary pathways for phase transitions in atmospheric water. These phase transitions affect the microphysics of clouds and have significant effects on the weather and climate. Our overall goal is to elucidate the mechanisms through which surfaces affect these transitions, and develop predictive abilities to correlate surface properties to the thermodynamics and kinetics of the phase transitions. In this work, we use molecular dynamics simulations to study the structure, and dynamics of water near kaolinite-like surfaces. Kaolinite is the most abundant mineral dust in the atmosphere. We specifically investigate the effect of …

Carbon Fibers Derived From Pan/Bio-Based Bicomponent Precursor, Jing Jin

Graduate Research and Discovery Symposium (GRADS)

No abstract provided.

Optimization Of Pyrochlore Catalysts For Dry Reforming Of Methane, Felipe Polo-Garzon, Ming He, David A. Bruce

Graduate Research and Discovery Symposium (GRADS)

No abstract provided.