Chemical Engineering Commons^™

Microstructural And Mechanical Characterization Of Soy-Based Polyethylene Fibers, Ozgun Ozdemir

All Theses

Bio-composite fibers have attracted increasing attention from environmentally-conscious consumers because of their low cost and biodegradability. Soy protein isolates and other purified forms have been proposed as bio-based substitutes for pure synthetic polymers for use in textiles. However, fibers from pure soy proteins do not possess adequate properties for use as textile fibers. Therefore, this research aimed to investigate composite fibers consisting of soy and polyethylene for their microstructure and mechanical properties. Changes in properties with increasing filler content and long-term properties of fibers were systematically examined.
First, the microstructure of the fibers was investigated by optical analysis. Six different …

Fabrication And Characterization Of Thermomechanically Processed Sulfur And Boron Doped Amorphous Carbon Films, Lonnie Carlson

Department of Chemical and Biomolecular Engineering: Theses and Student Research

Small scale, high power density, reliable, and long-life power supplies would be useful or even critical for space missions or the growing number of microdetectors, microsensors, and miniature vehicles. Alpha or beta particle voltaic devices could satisfy these requirements but have been shown to degrade quickly due to radiation damage. Amorphous carbon (a-C) PN junctions or PIN devices could provide radiation hardness and sufficiently high efficiency. As the range of alpha and beta particles in a-C is ~20-120μm, much thicker films than are typical are needed to maximize collection of the particle energy.

In this work, the fabrication of thermomechanically …

Adsorption Kinetics Of Pb(Ii) And Zn(Ii) Ions Unto Carbonized Groundnut Shells And Maize Cobs, Leke Luter, Aboi Julius, Henry T. Dekaa, B. A. Ikyenge, Ande Sesugh, Monday Uchenna Okoronkwo

Chemical and Biochemical Engineering Faculty Research & Creative Works

Maize cobs and groundnut shell adsorbents from agricultural by-products were carbonized and investigated for adsorption of two selected metals, Lead (Pb II) and Zinc (Zn II) from aqueous solutions of these metals. Kinetic studies of the adsorption processes were investigated employing Elovich and the intraparticle diffussion models. The results showed that, the adsorption capacities of these comparatively cheaper adsorbents and their efficiency for the removal of Pb(II) and Zn(II) ions from aqueous solution present them suitable for use in place of the costly commercial activated carbons.

Experimental Composite Guidance Conduits For Peripheral Nerve Repair: An Evaluation Of Ion Release, X. F. Zhang, A. Coughlan, H. O'Shea, Mark R. Towler, S. Kehoe, D. Boyd

Chemical and Biochemical Engineering Faculty Research & Creative Works

Poly (lactide-co-glycolide) (PLGA) - Pluronic F127 - glass composites have demonstrated excellent potential, from the perspective of controlled mechanical properties and cytocompatibility, for peripheral nerve regeneration. In addition to controlling the mechanical properties and cytotoxicity for such composite devices, the glass component may mediate specific responses upon implantation via degradation in the physiological environment and release of constituent elements. However, research focused on quantifying the release levels of such therapeutic ions from these experimental medical devices has been limited. To redress the balance, this paper explores the ion release profiles for Si⁴⁺, Ca²⁺, Na⁺, …

Enzyme Actuated Bioresponsive Hydrogels, Andrew Wilson

All Theses

Bioresponsive hydrogels are emerging with technological significance in targeted drug delivery, biosensors and regenerative medicine. Conferred with the ability to respond to specific biologically derived stimuli, the design challenge is in effectively linking the conferred biospecificity with an engineered response tailored to the needs of a particular application. Moreover, the fundamental phenomena governing the response must support an appropriate dynamic range and limit of detection. The design of these systems is inherently complicated due to the high interdependency of the governing phenomena that guide the sensing, transduction, and the actuation response of hydrogels. To investigate the dynamics of these materials, …

Characterization And Quantification Of Monomers, Oligomers, And By-Products From Xylan During Biomass Pretreatment, Ching-Shuan Lau

Graduate Theses and Dissertations

Biomass pretreatment generates inhibitory products, which reduce the overall yield of xylose for ethanol production. Understanding of hemicellulose depolymerization into xylose is essential to identify the pretreatment conditions that maximize xylose formation, but minimize the generation of these inhibitory products, such as formic acid and furfural. Thus, the goal of this project is to understand how dilute acid pretreatment parameters affect hemicellulose depolymerization, maximize xylose concentrations, and minimize by-products formation.

To progress towards this goal, rates and mechanisms of hemicellulose release must be determined. Birchwood xylan was used as the starting material to produce xylose oligomers. The hydrolyzed birchwood xylan …

Gallium Containing Glass Polyalkenoate Anti-Cancerous Bone Cements: Glass Characterization And Physical Properties, A. W. Wren, A. Coughlan, L. Placek, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

A gallium (Ga) glass series (0.48SiO₂-0.40ZnO-0.12CaO, with 0.08 mol% substitution for ZnO) was developed to formulate a Ga-containing Glass Polyalkenoate Cement (GPC) series. Network connectivity (NC) and X-ray Photoelectron Spectroscopy (XPS) was employed to investigate the role of Ga³⁺ in the glass, where it is assumed to act as a network modifier. Ga-GPC series was formulated with E9 and E11 polyacrylic acid (PAA) at 50, 55 and 60 wt% additions. E11 working times (T_w) ranged from 68 to 96 s (Lcon.) and 106 s for the Ga-GPCs (LGa-1 and LGa-2). Setting times (T_s) …

Utility Of 1,2,4-Triazoles As Catalysts For Orr In Fuel Cells, Chinmay Nagesh Dabke

Masters Theses

The Oxygen Reduction Reaction (ORR) taking place at the cathode of a fuel cell is catalyzed by Platinum due to its high activity and good stability in the acidic polymer electrolyte membrane fuel cell (PEMFC) environment. Due to its prohibitive cost and limited reserves, it is not practical to use Pt as the catalyst for mass commercialization. By taking inspiration from nature, we have devised a series of catalysts which will help in replacing Platinum at the cathode in commercial fuel cells. To gauge the activity of various ligands, metal salts and carbon surfaces, adsorbed experiments were carried out and …

Design Of Advanced Fouling-Resistant And Self-Cleaning Membranes For Treatment Of Oily And Impaired Waters, Daniel Wandera

All Dissertations

The overall goal of my Doctor of Philosophy (PhD) research was to design and develop advanced anti-fouling and self-cleaning membranes for treating impaired waters. Initial work focused on the development of membranes to treat produced water, which is oily wastewater that is co-produced during oil and gas exploration. Economical, environmentally sustainable treatment of the large volumes of produced water is a grand challenge for oil and gas companies. While membranes offer many advantages over more conventional treatment methods, membrane-based treatment processes for oily waters often fail due to membrane fouling. Therefore, the primary objective of my doctoral research was to …

The Influence Of Coating Structure On Sheet-Fed Offset Ink Setting Rates, Ting Chen

Masters Theses

Much attention has been paid to the study of quickset ink setting as a complex ink-coating interaction. Offset ink setting rates are typically measured as ink splitting forces versus time and the slope of the regression line obtained from a plot of these measured values is reported, but scant attention has been paid to the deviations from that straight line. An initial slow ink setting rate is desired to minimize back-trap mottle, carryover picking and piling and enhance ink gloss; then a faster ink setting rate during sheet delivery to the pile is desired to reduce the likelihood of ink …

The Reduction Of Glycerol Flow In A Porous Medium Through A Barrier Coating Application, Thomas Tran

Masters Theses

Coatings for paper are categorized into two groups: pigmented or functional. Functional coatings provide functionality in addition to the normal coating properties. Functional coatings can be used for friction control, release properties, abrasion resistance, and barrier properties. A coating that is designed to control barrier properties can be categorized into a sub-group of functional coatings called barrier coatings.

Barrier coatings can retard or eliminate the flow of fluids thru a coated substrate. The barrier can be effective in repelling or resisting the transmission rate of numerous fluids including moisture, oil, oxygen, grease, and glycerol. Barrier coatings have many useful applications …

Fabrication Of Printed Substrate For Surface Enhanced Raman Spectroscopy, Ali Eshkeiti

Masters Theses

A novel surface enhanced Raman spectroscopy (SERS) substrate was successfully fabricated on a silicon wafer using inkjet printing and on polyethylene terephthalate (PET) using gravure printing. Silver (Ag) nanoparticle (NP) based ink, was used for roughening of the surface of silicon and PET. A thickness of 400 nm was measured for the printed Ag NP printed film on silicon and the thickness of the single and double layered films on PET were measured as 340 nm and 680 nm, respectively by using vertical scanning interferometry. The Ag NP printed SERS substrate was tested for application with heavy metal compounds like …

Inkjet Printability Of Electronic Materials Important To The Manufacture Of Fully Printed Otfts, Sooman Lim

Dissertations

In this study, the inkjet printability of materials important to fabricating OTFTs was researched. In order to understand the jetting evolution of inkjet printed inks, simulations were performed with a nano copper and nano particle silver ink. To predict the inkjettability of the nano copper ink, Z and Oh numbers at different temperatures were determined. The results from the simulation studies were compared to experimental results obtained using a Dimatix inkjet printer. For the semiconductor ink, the inkjet printability of two organic semiconductors, P2TDC17FT4 (poly[(3,7-diheptadecylthieno[3,2-b]thieno[2',3':4,5]thieno[2,3-d]thiophene-2,6-diyl)[2,2'-bithiophene]-5,5'-diyl] dissolved in 1,2-dichlorobenzene and P3HT (poly-3 hexylthiophene) were compared to determine the relationship between drop …

Determination Of The Kinetic Parameter In The Photodegradation Of Phenol By A Unified Kinetic Model By Using Least Square Curve Fitting And The Genetic Algorithm., Jesus Moreira Del Rio, Benito Serrano, Hugo De Lasa

Jesus Moreira del Rio

No abstract provided.

Solid Oxide Fuel Cells With Both High Voltage And Power Output By Utilizing Beneficial Interfacial Reaction, Chao Su, Zongping Shao, Ye Lin, Yuzhou Wu, Huanting Wang

Faculty Publications

An intriguing cell concept by applying proton-conducting oxide as the ionic conducting phase in the anode and taking advantage of beneficial interfacial reaction between anode and electrolyte is proposed to successfully achieve both high open circuit voltage (OCV) and power output for SOFCs with thin-film samarium doped ceria (SDC) electrolyte at temperatures higher than 600 °C. The fuel cells were fabricated by conventional route without introducing an additional processing step. A very thin and dense interfacial layer (2–3 μm) with compositional gradient was created by in situ reaction between anode and electrolyte although the anode substrate had high surface roughness …

Homogeneous Viologens For Use As Catalysts In Direct Carbohydrate Fuel Cells, Dane C. Hansen

Theses and Dissertations

Deriving electrical energy from glucose and other carbohydrates under mild conditions is an important research objective because these biomolecules are abundant, renewable, and can provide 12 to 24 electrons per molecule, yielding substantial electrical power. It was previously observed that disubstituted viologens, salts of N,N'-disubstituted 4,4'-bipyridine, are able to oxidize glucose under alkaline conditions. Building on that initial result, the objective of this work was to understand and quantify the effectiveness and utility of viologens as catalysts for use in direct carbohydrate fuel cells.The extent that viologens oxidize carbohydrates, the conditions under which that oxidation occurs, and the mechanism for …

Order-Disorder Transition Of Aragonite Nanoparticles In Nacre, Zaiwang Huang, Xiaodong Li

Faculty Publications

Understanding nacre’s bottom-up biomineralization mechanism, particularly, how individual aragonite platelets are formed, has long remained elusive due to its crystallographic peculiarity and structural complexity. Here we report that crystallographic order-disorder transition can be triggered within individual aragonite platelets in pristine nacre by means of heat treatment and/or inelastic deformation, offering a unique opportunity to discriminate mysterious aragonite nanoparticles in transmission electron microscopy. Our findings unambiguously uncover why aragonite nanoparticles in pristine nacre have long been inaccessible under TEM observation, which is attributed to the monocrystal-polycrystal duality of the aragonite platelet. The underlying physical mechanism for why an individual aragonite platelet …

Capacitively Coupled Radio-Frequency Discharges In Nitrogen At Low Pressures, L. L Alves, L. Marques, C. D Pintassilgo, W. Wattieaux, Et. Es-Sebbar, J. Berndt, E. Kovačević, N. Carrasco, L. Boufendi, G. Cernogora

Dr. Et-touhami Es-sebbar

This paper uses experiments and modelling to study capacitively coupled radio-frequency (rf) discharges in pure nitrogen, at 13.56 MHz frequency, 0.1–1 mbar pressures and 2–30 W coupled powers. Experiments performed on two similar (not twin) setups, existing in the LATMOS and the GREMI laboratories, include electrical and optical emission spectroscopy (OES) measurements. Electrical measurements give the rf-applied and the direct-current-self-bias voltages, the effective power coupled to the plasma and the average electron density. OES diagnostics measure the intensities of radiative transitions with the nitrogen second-positive and first-negative systems, and with the 811.5 nm atomic line of argon (present as an …

Transparent Conducting Films Of Cdse(Zns) Core(Shell) Quantum Dot Xerogels, Lasantha Korala, Li Li, Stephanie L. Brock

Chemistry Faculty Research Publications

A method of fabricating sol–gel quantum dot (QD) films is demonstrated, and their optical, structural and electrical properties are evaluated. The CdSe(ZnS) xerogel films remain quantum confined, yet are highly conductive (10⁻³ S cm⁻¹). This approach provides a pathway for the exploitation of QD gels in optoelectronic applications.

Computational Modeling Of Functionalized Carbon Nanotubes, Nathaniel Lee Miller

Theses and Dissertations

Ab initio self-consistent field (SCF) molecular orbital calculations were performed employing various basis sets to computationally predict methods to functionalize and solubilize carbon nanotubes. The structure and Restricted Hartree-Fock (RHF) or “total” energies of functionalized nanotubes of various configurations were determined via theoretical calculations. Total energies were used to determine preferences for adsorption on nanotube sur-faces. Various diameter carbon nanotubes (CNTs) were tested to determine where a transition from a non-wrapping to a wrapping approach was found likely to occur as a function of diameter. Further refinements to this method could be used to explore additional interactions as nanotube diameter …