Engineering Commons^™

Methods And Challenges Of Experimental System Identification Of A Distillation Column, Marc Christopher Moss

Masters Theses and Doctoral Dissertations

University of Tennessee at Chattanooga Engineering Department distillation column is used as a teaching tool, but is currently without a feedback control system. An eventual goal of developing such a control system requires that the behavior of the column be understood. It is necessary to identify which of the column parameters can change, either ones that change to cause a disturbance, or ones that the controller can change in response to a disturbance. There are four of these parameters in the UTC column: feed flow rate, feed composition, reboiler heat and reflux percent. Experiments were performed on the column to …

Novel Techniques For The Synthesis Of Three-Way Catalytic Converter Support Materials, Prince Anyaba

All Dissertations

Current automobiles use catalytic converters, consisting of noble metals on an oxide support, to convert noxious engine exhaust pollutants into less harmful species. The development of mesoporous oxide supports with optimal pore geometries could enable these devises to decrease in size and weight and significantly reduce the metal loadings required to achieve optimal performance. Thus, in this work, I investigated a wide range of techniques for the synthesis of mesoporous oxides to determine if they could be adapted to ceria-zirconia-yttria mixed oxide (CZY) systems, which are the industry standard for the optimal oxide support for catalytic converter applications. Additionally, I …

Diesel Particulate Matter Quantification And Reduction Strategies For School Buses, David Martinez-Morett

Theses and Dissertations

This thesis evaluated the contributions of school bus self pollution from both the crankcase and the tailpipe emissions to in-cabin levels of fine and ultrafine particulate matter, and determined the effectiveness of commercially available retrofit technologies towards reducing levels of particulate matter inside the school bus passenger compartment. Mobile tests were conducted with a school bus powered by an International DT466E engine on an outdoor test track. Measurements of fine and ultrafine particle concentrations within the cabin of a school bus were performed with and without retrofit technologies.

The tests utilized a drive cycle using data from actual school bus …

Comparison Of An Experimental Bone Cement With A Commercial Control, Hydroset™, O. M. Clarkin, D. Boyd, S. Madigan, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Glass polyalkenoate cements based on strontium calcium zinc silicate glasses (Zn-GPCs) and high molecular weight polyacrylic acids (PAA) (MW; 52,000-210,000) have been shown to exhibit mechanical properties and in vitro bioactivity suitable for arthroplasty applications. Unfortunately, these formulations exhibit working times and setting times which are too short for invasive surgical applications such as bone void filling and fracture fixation. In this study, Zn-GPCs were formulated using a low molecular weight PAA (MW; 12,700) and a modifying agent, trisodium citrate dihydrate (TSC), with the aim of improving the rheological properties of Zn-GPCs. These novel formulations were then compared with commercial …

Electrospinning Route For The Fabrication Of P-N Junction Using Nanofiber Yarns, A. F. Lotus, S. Bhargava, E. T. Bender, E. A. Evans, R. D. Ramsier, Darrell Hyson Reneker, G. G. Chase

College of Polymer Science and Polymer Engineering

Electrospinning is a simple, versatile, and cost effective method for generating nanoscale fibers, wires, and tubes. Nanowires and nanotubes could be important building blocks for nanoscale electronics, optoelectronics, and sensors as they can function as miniaturized devices as well as electrical interconnects. We report on a simple method to fabricate free standing ceramic nanofiber heterostructures, which exhibit rectifying behavior of a p-n junction.

Modelling Of Coal Slag Flow And Layer Thickness In A High Temperature Entrained Flow Gasifier, H. Katalambula

Tanzania Journal of Engineering and Technology (TJET)

A 2-D model for the slag flow simulation in an entrained flow gasifier has been developed. In addition to mass, momentum and energy conservation equations, volume of fluid (VOF) equation was solved to track the liquid-gas interface. Liquid phase consists of melted coal ash particles which deposits on the wall and move downward. The gasification reaction is not considered here but it is postulated to have a mass flow through the interface towards the mass of the liquid phase. The reactor walls are usually kept cold so a temperature gradient and then a solid layer form within the slag layer. …

Nonlinear-Optical Studies Of A Fluorinated Poled Polyimide Guest-Host System, S. F. Hubbard, K. D. Singer, F. Li, Stephen Z. D. Cheng, F. W. Harris

College of Polymer Science and Polymer Engineering

We report on poling of a low dielectric constant preimidized fluorinated fully aromatic guest-host polyimide nonlinear optical material including thermal stability of optical nonlinearities and waveguiding properties. We measured a second-harmonic coefficient (d33 = 4.9 +/- 0.5 pm/V at 1217 nm fundamental wavelength) which is accurately predicted by a thermodynamic model of poled polymers. The optical nonlinearity of a poled sample was thermally stable at 80-degrees-C for over 300 h. Films were observed to have negative birefringence. Optical losses for slab waveguides in lowest order TE and TM modes were greater-than-or-equal-to 7.7 dB/cm for doped waveguides at 800 nm wavelength …

Investigation Of Additives For Use In Electroless Plating Solutions For Fabrication Of Nanowires, Elliott J. Bird

Theses and Dissertations

This study focused on improvement of electroless plating methods by use of particular bath additives. The techniques developed here can enable us to plate very thin layers selectively on a nonconductive substrate and thus create metallized features on a nanoscale. Through the development of such bottom-up techniques this work contributes a key technology to achieving self-assembled nanocircuits. The use of additives in an electroless plating environment can modify the barriers to nucleation (or seeding) and growth. Two additives, namely 3-mercapto-1-propanesulfonic Acid (MPS) and 1,3-propanedisulfonic acid (PDS), notably increased the selectivity of electroless metallization on chemically modified surfaces, which can be …

Web Based Classes For Enhancement Of Prelaboratory Lectures, Tiffany Hesser, Michael Collura

Chemistry and Chemical Engineering Faculty Publications

The use of web classes, such as Tegrity Campus1, as a supplement to pre laboratory reading or a replacement for pre laboratory lectures could become a standard tool in laboratory education protocol. In classes with multiple lab sections and instructors, pre laboratory lectures can lack consistency and it can be difficult to gauge the students’ level of preparation. With the ever increasing exposure to technology, students generally prefer information in a digital and multimedia form, rather than textbook readings. Therefore, this method can prove to better prepare students prior to laboratory experiments, increasing the overall understanding of the chemical reactions …

Universal Scaling Behavior In Startup Shear Of Entangled Linear Polymer Melts, Pouyan E. Boukany, Shi-Qing Wang, Xiaorong Wang

College of Polymer Science and Polymer Engineering

We have studied stress overshoot behavior in startup shear of four monodisperse polymer melts with a range of chain entanglement from Z = 24 to 160 entanglement points per chain. In the elastic deformation regime defined by (gamma)over dot tau(R) > 1 where tau(R) is the Rouse relaxation time, (i) the peak shear stress sigma(max) scales with the time t(max) at the peak to -1/2 power, in contrast to an exponent of -1/4 in the viscoelastic regime (for (gamma)over dot tau(R) < 1), (ii) sigma(max) changes linearly with the elapsed strain at the stress peak gamma(max), which scales with the applied shear rate as (gamma)over dot(1/3), (iii) a supermaster curve collapses time-dependent shear stress growth curves up to the stress maximum at all shear rates for all the four styrene-butadiene rubber samples. (C) 2009 The Society of Rheology. [DOI: 10.1122/1.3086872]

A Rapid Method For Flow-Ready Cylindrical Microchannel Fabrication, Kimberly H. Henthorn

Chemical and Biochemical Engineering Faculty Research & Creative Works

Most current methods of microchannel fabrication are expensive and time consuming or result in noncylindrical channels, which is undesirable for many applications. A rapid inexpensive method for the fabrication of flow-ready cylindrical polymer microchannels from polydimethylsiloxane (PDMS) is presented here. In this method, cylindrical needles are used as molds for the channels and also function as flow delivery devices after fabrication. Validation of channel function and smoothness can be accomplished by comparing experimental data to theoretical models. One model was previously developed by the author to predict the incipient motion of a glass sphere in contact with a perfectly smooth …

Production Of Biobutanol From Biomass Using Novel Membrane Reactor, Natalie Thibodeaux

Chemical Engineering Undergraduate Honors Theses

Producing biobutanol from a waste product on a large scale is a novel idea. Because of this, there is very little research available in this area. Previous fermentation research has primarily focused on the production of ethanol or biobutanol using cellulosic or agricultural feed stocks. The Phase I research team, Team R azorbacks E ngineering FU el S olutions for E veryone (Team REFUSE), sought to design a fermentation process that would produce butanol from food waste. Team REFUSE cultivated a partnership with Chartwells, the campus food service provider for the University of Arkansas, for the acquisition of food waste. …

Experimental Investigation Of Mixing Time In A Stirred, Torispherical-Bottomed Tank Equipped With A Retreat-Blade Impeller, Nonjaros Chomcharn

Theses

Glass-lined reactors are typically used in the pharmaceutical and specialty chemicals industries because of their material compatibility with most reactants and their cleanability. These reactors are typically equipped with a retreat-blade impeller placed close to the bottom of the tank a single baffle mounted from the top. The mixing performance of such reactors has not received significant attention in the literature, despite their ubiquitous presence in the pharmaceutical industry. In particular, mixing time, i.e., the time required by the system to achieve a predefined level of homogeneity, has not been studied to any significant degree.

In this work, the mixing …

Mixing Performance Of A Novel, Continuous Confined Impinging Jets Mixer Using Competitive Reactions, Han Zheng

Theses

In this work, a novel continuous flow apparatus featuring the impingement of fluid jet streams in the presence of ultrasonic energy provided by an ultrasonic probe was tested using competitive reactions in order to determine its mixing effectiveness. The ultrasonic energy enhances micromixing of the fluid jet streams, which results in an overall mixing effectiveness improvements in different physical and chemical processes.

In the competitive reactions system used here (third Bourne reaction), one stream containing sodium hydroxide was continuously fed to the first impinging jet, while an aqueous solution of hydrochloric acid and ethyl chloroacetate was fed to the second …

Electrode Of Metallic Oxides Coated Titanium With Interlayer, Yi Tang, Li-Kun Xu, Yong-Lei Xin, Jun-Tao Wang, Ping Long

Journal of Electrochemistry

Various Ti/IrRuSn,Ti/IrTa/IrRuSn and Ti/IrTaSn/IrRuSn oxide electrodes were prepared by sol-gel method.The surface morphology and microstructure were analysed with FESEM and XRD.The electrochemical activity and stability were investigated using electrochemical technologies including chlorine and oxygen evolving potential measurements,cyclic voltammetry,accelerated life test,and alternative electrolysis.The results indicate that the electrodes with interlayers present more cracks on the surface and a little bigger average grain size,with particles of different shapes precipitated in the cracks.The electroactive sites are increased and the selectivity for the chlorine evolving reaction is enhanced,but the current efficiency for the chlorine production is somewhat lowered by the addition of different interlayers.The …

Preparation And Electrochemical Properties Of Layered Manganese Oxide(Li-Birnessite Type), Xing-Kang Huang, Hai-Tao Chang, Jian-Long Gan, Qing-Shun Zhang, Hong-Jun Yue, Dong-Ping Lv, Yong Yang

Journal of Electrochemistry

Layered Li-birnessite was prepared by means of oxidizing Mn²⁺ with O₂ gas in alkaline media.The as-prepared sample was characterized by scanning electron microscopy(SEM), X-ray diffraction(XRD), BET and thermogravimetric/diffenential thermal analysis(TG/DTA) techniques. The electrochemical properties of the material were also investigated. The results show that such a Li-birnessite consists of well-crystallized spherical particles with an interlayer distance of 0.70 nm. The Li-birnessite delivered a high discharge capacity of 203 mAh/g at a rate of 0.2 C(40 mA/g), and had good rate capability as well.

Electro-Oxidation Of Methanol On Fe-Doped Pt-Zro2/C Catalyst, Mao-Cai Lin, Dong-Dong Liu, Qing-Chun Yu, Ming-Ruo Hu, Heng-Yong Tu

Journal of Electrochemistry

The Fe-doped ZrO₂ powders were prepared by so-gel method.After that,Pt-Zr_1-xFe_xO₂/C catalysts were made by reducing platinum salts with ethylene glycol.The physical property of the catalyst was characterized by XRD and TEM.It was found that the distribution of the catalyst was narrow,the particle sizes of Pt and ZrO₂ particles were 2~4 nm and 3~7 nm,respectively.The Cyclic Voltammetry and Chronoamperometry testing indicated that the electro-catalytic activity for methanol electro-oxidation on Pt-ZrO₂/C catalyst increased when ZrO₂ was doped with Fe.And Pt-Zr_0.95Fe_0.05O₂/C catalyst showed the highest activity …

Mechanics-Based Model For Non-Affine Swelling In Perfluorosulfonic Acid (Pfsa) Membranes, Ahmet Kusoglu, Michael H. Santare, Anette M. Karlsson

Mechanical Engineering Faculty Publications

A mechanics-based model is developed to predict the swelling pressure in perfluorosulfonic acid (PFSA) ionomer membranes during water uptake. The PFSA membrane is represented as a two-phase system, where the water-filled hydrophilic domains are dispersed throughout the hydrophobic polymer matrix. Two representative volume elements (RVEs) are used to represent the nanostructure: (i) a spherical RVE with a spherical hydrophilic domain at the center, and (ii) a cylindrical RVE with a cylindrical hydrophilic domain. The model starts with the non-affine swelling behavior of the membrane and interprets this as a structural reorganization of the RVEs to characterize the microscopic deformation. Swelling …

Incentive Based Routing Protocol For Mobile Peer To Peer Networks, Anil Jade, Sanjay Kumar Madria, Mark Linderman

Computer Science Faculty Research & Creative Works

Incentive models are becoming increasingly popular in Mobile Peer to Peer Networks (M-P2P) as these models entice node participation in return for a virtual currency to combat free riding and to effectively manage constraint resources in the network. Many routing protocols proposed are based on best effort data traffic policy, such as the shortest route selection (hop minimization). Using virtual currency to find a cost effective optimal route from the source to the destination, while considering Quality of Service (QoS) aspects such as bandwidth and service capacity constraints for data delivery, remains a challenging task due to the presence of …

Effects Of Photointensity Gradient On Directional Crystal Growth In Blends Of Crystalline Polymer And Photoreactive Monomer Undergoing Photopolymerization-Induced Phase Transformation, Pankaj Rathi, Soo Jeoung Park, Thein Kyu

College of Polymer Science and Polymer Engineering

Effects of light intensity gradient on development of intricate hierarchical morphology of semicrystalline polyethylene oxide (PEO) and photoreactive diacrylate (DA) blends undergoing photopolymerization-induced crystallization have been demonstrated experimentally and theoretically. The melting temperature of PEO was found to decline upon addition of DA monomer. A solid-liquid phase diagram has been established by self-consistently solving the combined phase field free energy of crystal solidification and Flory-Huggins (FH) free energy of liquid-liquid demixing. Dynamic calculations were performed using time-dependent Ginzburg-Landau (model C) equations by incorporating the combined phase field and FH free energy densities coupled with the photopolymerization kinetics. The spatiotemporal development …

Rheological, Thermal And Processing Studies Of Perfluorocyclobutyl (Pfcb) Polymers, Erick Vasquez

All Theses

Polymeric materials are of interest to the fiber optics industry as glass–silica fibers are prone to fracture. However, the thermal resistance properties of current polymeric materials have limited their use in some optical applications including high performance lasers and high speed telecommunication systems. Therefore, it is of interest to develop new polymer materials and systems with enhanced thermal properties and processability for application in optics. This work focuses on the novel Perfluorocyclobutyl (PFCB) polymer systems. PFCB polymers possess characteristics that make them suitable for optics applications including: a low refractive index, high thermal stability and high chemical resistance. However, little …

Production Of Biobutanol From Biomass Using Novel Membrane Reactor: A P3 Experience, Ashley Haub

Chemical Engineering Undergraduate Honors Theses

Producing biobutanol from a waste product on a large scale is a novel idea. Because of this, there is very little research available in this area. Previous fermentation research has primarily focused on the production of ethanol or biobutanol using cellulosic or agricultural feed stocks. The Phase I research team, Team R azorbacks E ngineering FU el S olutions for E veryone (Team REFUSE), sought to design a fermentation process that would produce butanol from food waste. Team REFUSE cultivated a partnership with Chartwells, the campus food service provider for the University of Arkansas, for the acquisition of food waste. …

A Robust Process For Biodiesel Production Using Supercritical Methanol, Meagan Magie

Chemical Engineering Undergraduate Honors Theses

The overarching purpose of Phase I was to test, at the bench scale, a continuous supercritical methanol reactor, and to determine the feasibility of implementing the technology at full scale. Specific objectives in reaching this purpose included:
Objective 1: Choose a viable feedstock
Objective 2: Perform experiments for oil extraction
Objective 3: Design, build and operate a continuous supercritical methanol reactor
Objective 4: Design and simulate full scale biodiesel facility
Objective 4a: Perform life-cycle and economic analysis on full scale design
Objective 5: Prepare a Phase II P3 project to demonstrate the entire biodiesel process
Project Scope: The students performed …

Synthesis And Analysis Of Nano-Thin Polymer Films For Separation Applications, Azadeh Samadi-Dezfouli

All Dissertations

This dissertation focuses on the fabrication of uniform polymer nanolayers using surface-initiated polymerization. The kinetics of low temperature surface-initiated atom transfer radical polymerization (ATRP) is discussed in detail. The work is then extended to the surface modification of polymeric membranes to tune the physical and chemical properties of the membranes for gas separations. I discuss how atom transfer radical polymerization might be advantageous compared to some of the techniques that have been proposed in the literature for preparing polymeric membranes for CO2 separation.
The first part of this dissertation describes the synthesis of polystyrene (PS) nanolayers by surface-initiated ATRP at …

A Robust Process For Biodiesel Production Using Supercritical Methanol, Travis Roberts

Chemical Engineering Undergraduate Honors Theses

The overarching purpose of Phase I was to test, at the bench scale, a continuous supercritical methanol reactor, and to determine the feasibility of implementing the technology at full scale. Specific objectives in reaching this purpose included:
Objective 1: Choose a viable feedstock
Objective 2: Perform experiments for oil extraction
Objective 3: Design, build and operate a continuous supercritical methanol reactor
Objective 4: Design and simulate full scale biodiesel facility
Objective 4a: Perform life-cycle and economic analysis on full scale design
Objective 5: Prepare a Phase II P3 project to demonstrate the entire biodiesel process
Project Scope: The students performed …

A Robust Process For Biodiesel Production Using Supercritical Methanol, Thomas Kasprowicz

Chemical Engineering Undergraduate Honors Theses

The overarching purpose of Phase I was to test, at the bench scale, a continuous supercritical methanol reactor, and to determine the feasibility of implementing the technology at full scale. Specific objectives in reaching this purpose included:
Objective 1: Choose a viable feedstock
Objective 2: Perform experiments for oil extraction
Objective 3: Design, build and operate a continuous supercritical methanol reactor
Objective 4: Design and simulate full scale biodiesel facility
Objective 4a: Perform life-cycle and economic analysis on full scale design
Objective 5: Prepare a Phase II P3 project to demonstrate the entire biodiesel process
Project Scope: The students performed …

A Kinetic Study Of In Vitro Lysis Of Mycobacterium Smegmatis , William J. Valente, Elsje Pienaar, A. Fast, A. Fluitt, Scott E. Whitney, Robert J. Fenton, Raul G. Barletta, O. Chacon, Hendrik J. Viljoen

Hendrik J. Viljoen Publications

The traditional diagnostic tests for tuberculosis consist of an acid fast stain and a culture test from a sputum sample. With the emergence of drug resistant strains of tuberculosis, nucleic acid amplification has become the diagnostic test of choice. The nucleic acid amplification test consists of four steps: sputum sample collection, lysis of bacilli to release DNA, DNA amplification by PCR and detection of PCR products. The DNA extraction step has been largely overlooked and this study describes a systematic approach to measure the kinetics of cell lysis in a Tris–EDTA buffer. Mycobacterium smegmatis is a saphorytic, fast-growing mycobacterium that …

Production Of Biobutanol From Biomass Using Novel Membrane Reactor: A P3 Experience, Ellen Draehn

Chemical Engineering Undergraduate Honors Theses

Producing biobutanol from a waste product on a large scale is a novel idea. Because of this, there is very little research available in this area. Previous fermentation research has primarily focused on the production of ethanol or biobutanol using cellulosic or agricultural feed stocks. The Phase I research team, Team R azorbacks E ngineering FU el S olutions for E veryone (Team REFUSE), sought to design a fermentation process that would produce butanol from food waste. Team REFUSE cultivated a partnership with Chartwells, the campus food service provider for the University of Arkansas, for the acquisition of food waste. …

Proximate Characterization And Lycopene Determination In Bitter Melon Seed Aril, Luis Raul Jimenez Interiano

Chemical Engineering Undergraduate Honors Theses

Bitter melon aril is the mucilage covering the fruit's seeds which could contain beneficial dietary ingredients. The bright red color of bitter melon aril suggests that it could contain lycopene. The purpose of this study was to determine the proximate composition of bitter melon aril and to explore this material as a potential rich source of lycopene that has health benefits. Bitter melon aril from Sri Lanka, harvested in Arkansas, USA in 2005, 2006, and 2007 was analyzed. An investigation to develop an extraction method for lycopene from bitter melon was performed using liquid-liquid and a polar liquid extraction. The …

Understanding The Effects Of Hydrophobicity For The Detection Of Methylated Dna By Microchannel Electrophoresis, Micah Fritsche

Chemical Engineering Undergraduate Honors Theses

DNA methylation is an epigenetic mechanism used for long - term silencing of gene expression. This silencing of gene expression can be involved in the down regulation of genes involved in apoptosis, which is a process of regulated cell death, and this inability to break down cells can ultimately lead to tumor formation in cancer. Methylation of DNA follows a certain pattern through developmental stages of an individual, and this pattern is normally maintained throughout that individual's life. However, in the DNA of older individuals, this methylation is commonly seen to be altered. This altered pattern of methylation can be …