Chemical Engineering Commons^™

Adsorption And Electrooxidation Of Carbon Monoxide On Platinum Surfaces Modified With Sulfur, A. Mattox Mathew, W. Henney Matthew, Johnson Adam, Zou Shouzhong

Journal of Electrochemistry

Adsorbed sulfur is commonly considered as a reaction poison. However, small amounts of sulfur on platinum significantly increase the surface reactivity toward carbon monoxide (CO) electrooxidation. For the solution CO oxidation, the onset potential was shifted up to over 300 mV negative to that on S-free surface, and the extent of the negative potential shift increases with the sulfur coverage (X_s) up to about 0.6. The enhanced CO oxidation also depends on the solution pH. For the adsorbed CO, at low sulfur coverages (X_s < 0.3), the oxidation peak potential is about 40 mV negative to that of the corresponding clean Pt. However, at higher coverages, the peak potential is about 30 mV more positive. Surface-enhanced Raman spectra show that the adsorption of sulfur significantly redshifts the Pt-CO stretching frequency. These observations are explained by the weakening of the Pt-CO bond and the hindrance of CO diffusion by Sads.

Kinetic Study Of Photoelectrochemical Oxidation Of Lignin Model Compounds On Tio2 Nanotubes, Min Tian, Daniel Liba, Aicheng Chen

Journal of Electrochemistry

In this study, TiO₂ nanotubes were prepared via the electrochemical oxidation of titanium substrates in a non-aqueous electrolyte and their morphology and microstructures were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The photoelectrochemical oxidation of two lignin model compounds, 1-(3,4-dimethoxyphenoxy)-2-(2-methoxyphenoxy)-1,3-propanediol (DMP) and 3-hydroxy-1-(3,4-dimethoxyphenoxy)-2-(2-methoxyphenoxy)-1,3-propanone (HDM), was investigated. A new band appeared at ~304 nm during the photoelectrochemical oxidation of DMP. The rate of DMP intermediate formation was amplified with the increase of initial concentrations, while it was diminished with increased temperature. Despite the similarity in structure between HDM and DMP, there are only small increases in absorbance …

Advances And Challenges Of Intermediate Temperature Solid Oxide Fuel Cells: A Concise Review, Sanping Jiang

Journal of Electrochemistry

Fuel cell is an electrochemical energy conversion device to directly convert the chemical energy of fuels to electricity. Among all types of fuel cells, solid oxide fuel cells (SOFCs) operating at intermediate temperatures of 600~800 ^oC offer an attractive option that is much more fuel flexible than low temperature fuel cells such as proton exchange membrane fuel cells, and is suitable for a wide range of applications. However, two main challenges remain towards the commercial viability and acceptance of the SOFC technologies: the cost and durability. Both are critically dependent on the process, fabrication, performance, chemical and microstructural stability …

Ternary Alloy Electrocatalysts For Oxygen Reduction Reaction, Jin Luo, Lefu Yang, Binghui Chen, Chuanjian Zhong

Journal of Electrochemistry

Proton exchange membrane fuel cell represents an important electrochemical energy conversion device with many attractive features in terms of efficiency of energy conversion and minimization of environmental pollution. However, the large overpotential for oxygen reduction reaction at the cathode and the low activity, poor durability and high cost of platinum-based catalysts in the fuel cells constitute a focal point of major barriers to the commercialization of fuel cells. The development of nanostructured catalysts shows promises to addresses some of the challenging problems. The ability to engineer the composition and nanostructure of nanoalloy catalysts is important for developing active, robust and …

Electrocatalytic Activity Of Palladium Nanocatalysts Supported On Carbon Nanoparticles In Formic Acid Oxidation, Jie Huang, Zhiyou Zhou, Yang Song, Xiongwu Kang, Ke Liu, Wancheng Zhou, Shaowei Chen

Journal of Electrochemistry

Palladium nanostructures were deposited onto carbon nanoparticle surface by a chemical reduction method. Transmission electron microscopic studies showed that whereas the resulting metal-carbon (Pd-CNP) nanocomposites exhibited a diameter of 20 to 30 nm, the metal components actually showed a cauliflower-like surface morphology that consisted of numerous smaller Pd nanoparticles (3 to 8 nm). Electrochemical studies showed that the effective surface area of the Pd-CNP nanoparticles was about 40% less than that of Pd black, possibly because the Pd nanoparticles were coated with a layer of carbon nanoparticles; yet, the Pd-CNP nanocomposites exhibited marked enhancement of the electrocatalytic activity in formic …

Electrocatalytic Oxidation Of Formic Acid On Pd/Ni Heterostructured Catalyst, Mingjun Ren, Liangliang Zou, Ju Chen, Ting Yuan, Qinghong Huang, Haifeng Zhang, Hui Yang, Songlin Feng

Journal of Electrochemistry

A Pd/Ni bimetallic nanostructured electrocatalyst was fabricated via a two-step reduction route. Owing to an epitaxial growth of Pd atoms on the surface of Ni nanoparticles, heterostructured Pd/Ni nanocomposites were formed and verified by high resolution transmission electron microscopy combined with energy-dispersion X-ray spectroscopy. X-ray diffraction confirmed that the as-prepared Pd/Ni nanocomposites possessed a single face-centered-cubic (fcc) Pd structure, probably due to a weaker diffraction intensity of metallic Ni and/or overlapping by that of Pd. The intrinsic catalytic activity on the Pd/Ni is higher than that on the Pd. Moreover, the durability of formic acid oxidation on the Pd/Ni was …

Analysis Of The Enzymatic Decomposition Of Barley Starch To Simple Carbohydrates, Mark Mathiew Williams

Master's Theses

The decomposition of barley starch plays a fundamental role in the final quality of fermented beverages in the brewing industry. The process of mashing involves steeping milled barley in water to stimulate the enzymatic decomposition of starch into simple carbohydrates. The temperature of the water significantly impacts the activity of the enzymes and in turn the resulting concentrations of sugar products. A kinetic model accurately predicting the types and quantities of sugars formed as a function of mash temperature would serve as a tool to tailor sugar profiles and optimize mashing procedures for a desired product.

Sixty minutes mashes were …

Streamlined Extract Preparation For E. Coli-Based Cell-Free Protein Synthesis And Rapid Site-Specific Incorporation Of Unnatural Amino Acids In Proteins, Prashanta Shrestha

Theses and Dissertations

This thesis reports the viability of E. coli cell extracts prepared using equipment that is both common to biotechnology laboratories and able to process small volume samples and expression of proteins containing unnatural amino acids (UAAs) at higher level using PCR amplified linear DNA templates (LETs) in cell-free protein synthesis (CFPS) system. E. coli-based cell extracts are a vital component of inexpensive and high-yielding CFPS reactions. However, effective preparation of E. coli cell extract is limited to high-pressure homogenizers (French press style or impinge-style) or bead mill homogenizers, which all require a significant capital investment. This work specifically assessed the …

Liquid-Liquid Equilibrium Of Biodiesel Components, Joseph C. Bell

Theses and Dissertations

Biodiesel is produced from vegetable oils through transesterification. Triglyceride mixtures extracted from oilseed feedstocks are upgraded by reaction with an alcohol in the presence of a catalyst to produce fatty acid esters. This reaction produces a mixture of esters, glycerin, alcohol, and catalyst. Separation of the fatty acid esters (biodiesel) and glycerin can be accomplished through liquid-liquid extraction by water addition. Designing liquid-liquid extraction with water as the solvent requires ternary liquid-liquid equilibrium data for mixtures of water, glycerin, and fatty acid esters. Ternary mixture LLE data have been experimentally measured for several of these systems. Those measured include mixtures …

Model Development And Application Of Molecular Simulations For The Study Of Proton Transport In Bulk Water And For The Prediction Of Dipole Moments Of Organic Compounds, Abhishek Asthana

Theses and Dissertations

The present work demonstrates the application of molecular simulations (MD) in two different areas: proton transport in bulk water and estimation of the dipole moment of polar organic compounds. In both areas, relatively few successful and robust methodologies exist. In the first part, a new polarizable water model is developed for MD simulations of the proton transport process. The model was parametrized from a combination of quantum chemical calculations and experimental water properties. The model was implemented in MD simulation studies of liquid water at room temperature, as well as with excess protons. For pure water the model gave good …

Computational Identification Of Adaptive Mutants Using The Vert System, James Winkler, Katy Kao

Faculty Publications

BackgroundEvolutionary dynamics of microbial organisms can now be visualized using the Visualizing Evolution in Real Time (VERT) system, in which several isogenic strains expressing different fluorescent proteins compete during adaptive evolution and are tracked using fluorescent cell sorting to construct a population history over time. Mutations conferring enhanced growth rates can be detected by observing changes in the fluorescent population proportions.ResultsUsing data obtained from several VERT experiments, we construct a hidden Markov-derived model to detect these adaptive events in VERT experiments without external intervention beyond initial training. Analysis of annotated data revealed that the model achieves consensus with human annotation …

Brazel, Christopher S.: Fundamental Principles Of Polymeric Materials (Book Review), Jeffrey H. Glans

Chemistry & Physics Faculty Publications

Book review by Jeffrey H. Glans:

Brazel, Christopher S. and Stephen L. Rosen. Fundamental principles of polymeric materials. 3rd ed. Wiley, 2012.

ISBN 9780470505427

Membrane Separation Of Cu-67 For Use In Theranostics, Benjamin Fugate, Maura Sepesy, Kevin Pataroque, Christine Duval

Intersections Fall 2020

Because of its β− and γ decay routes, 67Cu is a very promising radioisotope for use in theranostic cancer treatments. Currently, 67Cu is produced through the irradiation of either 68Zn or 67Zn in a cyclotron, a traditional nuclear reactor or a linear electron accelerator. Once formed, a small amount of copper (nanograms) has to be separated from the large amount of remaining zinc (grams) and undesired byproduct isotopes such as 66Ga, 67Ga, 64Cu, 61Cu, 58Co. Currently, such separations are performed in resin-packed columns and can require 4 h to purify a 5 g target. These procedures may involve multiple columns …

Colorimetric Oxygen Imaging And Quantification With Easily Accessible Optical Devices, Satya Achanta, Sanghan Park, Chang-Soo Kim

Electrical and Computer Engineering Faculty Research & Creative Works

Optical oxygen imaging is essential in monitoring two-dimensional analysis of oxygen distribution. Two easily accessible optical devices were used for oxygen analysis to demonstrate the feasibility of an innovatively simple method. a light panel screen with light-emitting diode (LED) backlight was used as a light source to excite a luminophore film responsive to oxygen. Meso-scale fluidic sensor platform was prepared using porphyrin complex (PtOEP) as the luminophore embedded within ethyl cellulose (EC) polymer matrix. Green LED light uniformly displayed from the light panel excited the luminophore film to exhibit two-dimensional luminescence distribution corresponding to wet gaseous oxygen. a color camera …

Modeling, Fabrication And Characterization Of Scalable Electroless Gold Plated Nanostructures For Enhanced Surface Plasmon Resonance, Gyoung Gug Jang

Graduate Theses and Dissertations

The scientific and industrial demand for controllable thin gold (Au) film and Au nanostructures is increasing in many fields including opto-electronics, photovoltaics, MEMS devices, diagnostics, bio-molecular sensors, spectro-/microscopic surfaces and probes. In this study, a novel continuous flow electroless (CF-EL) Au plating method is developed to fabricate uniform Au thin films in ambient condition. The enhanced local mass transfer rate and continuous deposition resulting from CF-EL plating improved physical uniformity of deposited Au films and thermally transformed nanoparticles (NPs). Au films and NPs exhibited improved optical photoluminescence (PL) and surface plasmon resonance (SPR), respectively, relative to batch immersion EL (BI-EL) …

Gas Adsorption In Novel Environments, Including Effects Of Pore Relaxation, W. Milton Cole, Silvina M. Gatica, Hye Young Kim, Angela D. Lueking, Sarmishtha Sircar

Chemical and Biochemical Engineering Faculty Research & Creative Works

Adsorption experiments have been interpreted frequently with simplified model geometries, such as ideally flat surfaces and slit or cylindrical pores. Recent explorations of unusual environments, such as fullerenes and metal-organic-framework materials, have led to a broadened scope of experimental, theoretical and simulation investigations. This paper reviews a number of such studies undertaken by our group. Among the topics receiving emphasis are these: universality of gas uptake in pores, relaxation of a porous absorbent due to gas uptake and the novel phases of gases on a single nanotube, all of which studies have been motivated by recent experiments.

Fabrication Of Cao-Nao-Sio2/Tio2 Scaffolds For Surgical Applications, A. W. Wren, A. Coughlan, K. E. Smale, S. T. Misture, B. P. Mahon, O. M. Clarkin, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

A series of titanium (Ti) based glasses were formulated (0.62 SiO₂-0.14 Na₂O-0.24 CaO, with 0.05 mol% TiO₂ substitutions for SiO₂) to develop glass/ceramic scaffolds for bone augmentation. Glasses were initially characterised using X-ray diffraction (XRD) and particle size analysis, where the starting materials were amorphous with 4.5 μm particles. Hot stage microscopy and high temperature XRD were used to determine the sintering temperature (̃700 °C) and any crystalline phases present in this region (Na₂Ca₃Si₆O₁₆, combeite and quartz). Hardness testing revealed that the Ti-free control (ScC- …

A Mechanistic Model Of Early Fcεri Signaling: Lipid Rafts And The Question Of Protection From Dephosphorylation, Dipak Barua, Byron Goldstein

Chemical and Biochemical Engineering Faculty Research & Creative Works

We present a model of the early events in mast cell signaling mediated by FcεRI where the plasma membrane is composed of many small ordered lipid domains (rafts), surrounded by a non-order region of lipids consisting of the remaining plasma membrane. The model treats the rafts as transient structures that constantly form and breakup, but that maintain a fixed average number per cell. The rafts have a high propensity for harboring Lyn kinase, aggregated, but not unaggregated receptors, and the linker for the activation of T cells (LAT). Phosphatase activity in the rafts is substantially reduced compared to the nonraft …

Using The Greet Model To Analyze Algae As A Feedstock For Biodiesel Production, Christopher Tatum

Masters Theses and Doctoral Dissertations

There is a growing interest in renewable, carbon-neutral biofuels such as ethanol and biodiesel. A life-cycle analysis is conducted in this study to determine the viability of using algae as a feedstock for biodiesel. The method involves assessing energy use, fossil fuel use, greenhouse gas emissions, and criteria pollutant emissions using a simulation developed by Argonne National Laboratory. The energy and emissions of algae-derived biodiesel are compared to those of soybean biodiesel, corn ethanol, conventional gasoline, and low-sulfur diesel. Results show that there are sizeable greenhouse gas emission benefits attributed to the production of both types of biodiesel as compared …

Pvt Study Of Selected Uae Reservoir Fluids, Rashid Sher Mohammad

Theses

Phase behavior modeling in crude oil includes prediction of thermodynamic properties (such as saturation pressure, density, viscosity, thermal conductivity, etc.) for the vapor and liquid phases. The aim of phase behavior modeling is to establish the accuracy and reliability of the developed equation of state model to predict various other fluid phase behavior properties at high pressure and temperature conditions.

In the first part of this work, a new and reliable phase behavior apparatus designed in Brazil was used for the two-stage recombination process and phase behavior measurements. The recombination of the surface sample fluids (first-stage separator gas and stock-tank …

Gravure Printability Of Indium Tin Oxide Nanoparticles On Glass And Pet Films For Applications In Printed Electronics, Dania Awni Alsaid

Dissertations

The advancements in the field of solution processable electro-active materials and their ability to be printed on different substrates have led to the evolution of printed electronics. In this field, electronic components are manufactured with conventional printing methods. Transparent electrodes made from indium tin oxide (ITO) are part of many electronic devices. Currently in industry, highly conductive ITO films are prepared by sputtering. The sputtering and then patterning of ITO films is a sophisticated process that consumes high energy, generates waste and produces films with limited flexibility. Therefore, there is a need to investigate processing methods for creating ITO films …

Application Of Carbon Dioxide Towards The Development Of Smart Materials, Green Reaction Schemes And Metallic Nanoparticle Synthesis, Fiaz Mohammed

All Dissertations

Global carbon dioxide (CO₂) emissions have steadily risen over the last 50 years, with 34 billion tons of CO₂ released in 2009 alone. Its potential as a greenhouse gas has negatively affected of our lives and environment by the resulting ocean acidification and climate change. To mitigate atmospheric CO₂, various strategies have been implemented for CO₂ separation, capture, storage and use as a chemical feedstock. The use of CO₂ in various chemical industries is attractive as its non-flammable, non-toxic, and relatively inert properties have made it an inherently safer alternative to traditional organic …

Refractive Index Chemical Sensing With Noble Metal Nanoparticles, Phillip Blake

Graduate Theses and Dissertations

Chemical sensing is a key component in modern society, especially in engineering applications. Because of their widespread impact, improvements to chemical sensors are a significant area of research. One class of sensors, plasmonic sensors, is being heavily researched because of their ability to detect low levels of analyte in near real time without destroying the analyte. This work studies a new class of plasmonic sensor that utilizes diffractive coupling to improve sensor performance. Specifically, this work outlines the first study of diffractive coupling sensors with typical nanoparticle shapes. Sensitivity of this new class of sensor is directly compared to typical …

Capillary And Microchip Electrophoresis For The Monitoring Of Disease Causing Amyloid Proteins, Elizabeth Nancy Pryor

Graduate Theses and Dissertations

The detection of oligomers and aggregates formed by two amyloid proteins, insulin and amyloid-beta (AB), is of particular importance due to the role which these species play in Diabetes and Alzheimer's disease, respectively. However, existing techniques are limited in the ability to detect insulin and AB; oligomers due to the fact that these early aggregates are transient, present at low concentrations, and difficult to isolate. Improvements must be made to existing techniques or alternative techniques must be explored in order to identify and quantify the size of these oligomeric and aggregate species without disrupting their structure.

Capillary and microchip electrophoresis …

Site-Specific Metallization Of Multiple Metals On A Single Dna Origami Template, Bibek Uprety

Theses and Dissertations

This work examines the selective deposition of two different metals on the same DNA origami template for nanofabrication. DNA, with adjustable size and shape serves as a suitable template for fabricating metal junctions in the nanometer domain via bottom-up assembly. Bottom-up assembly utilizes the recognition capability of molecules like DNA to self-assemble and form structures. In this regard, DNA origami provides a useful means for forming nanostructures by folding single-stranded DNA into different two and three dimensional shapes. Selective deposition of metal on specific locations of a DNA template is essential for making DNA-templated electronic circuits.Site-specific metallization of DNA origami …

Reactive Rayleigh–Taylor Turbulent Mixing: A One-Dimensional-Turbulence Study, E.D. Gonzalez-Juez, A.R. Kerstein, D.O. Lignell

Faculty Publications

We study the problem of reactive Rayleigh–Taylor turbulence in the Boussinesq framework using one-dimensional-turbulence (ODT) simulations. In this problem a reaction zone between overlying heavy/cold reactants and underlying light/hot products moves against gravity. First, we show that ODT results for global quantities in non-reactive Rayleigh–Taylor turbulence are within those from direct numerical simulations (DNS). This comparison give us confidence in using ODT to study unexplored flow regimes in the reactive case. Then, we show how ODT predicts an early stage of reactive Rayleigh–Taylor turbulence that behaves similarly to the non-reactive case, as observed in previous DNS. More importantly, ODT indicates …

Fib/Sem-Based Calculation Of Tortuosity In A Porous Licoo2 Cathode For A Li-Ion Battery, T. Hutzenlaub, A. Asthana, J. Becker, D. R. Wheeler, R. Zengerle, S. Thiele

Faculty Publications

We present a new method to quantify tortuosity in the porous, LiCoO2 cathode of a Li-ion battery. The starting point is a previously published 3D reconstruction from FIB/SEM images with three phases, the active material domain, carbon-binder domain and pore space. Based on this geometrical configuration, we compute effective diffusivities, from which we in turn derive tortuosity values for the pore space ranging between 5 and 11.6 for the three spatial directions. In a next step, we compare our approach to an imaging method that employs back-filling material. These methods do not differentiate between the carbon-binder domain and the pore …

Incorporation Of Catalytic Dehydrogenation Into Fischer-Tropsch Synthesis To Significantly Reduce Carbon Dioxide Emissions, Gerald P. Huffman

Chemical and Materials Engineering Faculty Patents

A new method of producing liquid transportation fuels from coal and other hydrocarbons that significantly reduces carbon dioxide emissions by combining Fischer-Tropsch synthesis with catalytic dehydrogenation is claimed. Catalytic dehydrogenation (CDH) of the gaseous products (C1-C4) of Fischer-Tropsch synthesis (FTS) can produce large quantities of hydrogen while converting the carbon to multi-walled carbon nanotubes (MWCNT). Incorporation of CDH into a FTS-CDH plant converting coal to liquid fuels can eliminate all or most of the CO₂ emissions from the water-gas shift (WGS) reaction that is currently used to elevate the H₂ level of coal-derived syngas for FTS. Additionally, the …

Ultrasound-Induced Phase Change Of Emulsion Droplets For Targeted Gene And Drug Delivery, James R. Lattin

Theses and Dissertations

This dissertation explores the potential of using perfluorocarbon emulsion droplets to add an ultrasound-sensitive element to drug delivery systems. These emulsion droplets may be induced to vaporize with ultrasound; during the rarefactional phase of an ultrasound wave, the pressure around the droplets may fall below the vapor pressure of the liquid forming the emulsion, providing a thermodynamic potential for vaporization. This ultrasound-induced phase change of the emulsion droplet could release therapeutics attached to the droplet surface or aid in drug delivery due to mechanical effects associated with vaporization and expansion, similar to the ability of cavitating bubbles to aid in …

Beyond Gel Electrophoresis: Microfluidic Separations, Fluorescence Burst Analysis, And Dna Stretching, Kevin D. Dorfman, Scott B. King, Daniel W. Olson, Joel D. P. Thomas, Douglas R. Tree

Faculty Publications

This review addresses methods for obtaining sequence information directly from unamplified genomic length DNA. Our generic starting point is a large piece of DNA that contains many thousands of base pairs (kilobase pairs, kbp) or even millions of base pairs (megabase pairs, Mbp). We would like to determine the genomic distance between two repeats of a given sequence, indicated by the red dots on the coiled DNA molecule in Figure 1. Let us consider the case where these sequences are restriction sites, which can be selectively cut using proteins known as restriction enzymes. For decades, gel electrophoresis served as the …