Chemical Engineering Commons^™

Opto-Thermal Characterization Of Plasmon And Coupled Lattice Resonances In 2-D Metamaterial Arrays, Vinith Bejugam

Graduate Theses and Dissertations

Growing population and climate change inevitably requires longstanding dependency on sustainable sources of energy that are conducive to ecological balance, economies of scale and reduction of waste heat. Plasmonic-photonic systems are at the forefront of offering a promising path towards efficient light harvesting for enhanced optoelectronics, sensing, and chemical separations. Two-dimensional (2-D) metamaterial arrays of plasmonic nanoparticles arranged in polymer lattices developed herein support thermoplasmonic heating at off-resonances (near infrared, NIR) in addition to regular plasmonic resonances (visible), which extends their applicability compared to random dispersions. Especially, thermal responses of 2-D arrays at coupled lattice resonance (CLR) wavelengths were comparable …

Screen Printed Moisture Sensor On Barrier Coated Sbs Board: The Characterizations Of The Hemicellulose-Based Biofilms And Their Applications For Smart Packaging, Ruoxi Ma

Dissertations

Fiber-based packaging materials have many advantages over their petroleum-based plastic competitors, such as sustainability, recyclability and stiffness/weight ratio. However, the poor barrier properties and sensitivity towards moisture are the main challenges for their extended use. Therefore, there has been a need to provide a biodegradable and biocompatible biopolymer packaging material with improved barrier properties for food and pharmaceutical packaging. Also, the moisture loss/gain problem causes a lot of waste every year. Therefore, there is a need of better tracking and sensing methods attached to the package in order to control the moisture level along the supply chain. To accomplish these …

First Principles-Based Microkinetic Modeling Of Ethanol From Syngas On Bimetallic Co-Pd Catalysts, Anuradha Gundamaraju

All Dissertations

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 …

Pyrolysis Of Plastic Waste From Medical Services Facilities Into Potential Fuel And/Or Fuel Additives, Bright Kweku Ansah Baiden

Masters Theses

Limited space and high costs for landfilling as well as increasing regulations in plastic waste disposal, has led to high operating costs for organizations involved in managing plastic waste from medical facilities which led to the need to investigate an alternative option such as pyrolysis. The overall goal of this study was to evaluate pyrolysis as a means to repurpose plastic waste obtained from medical service facilities into fuel and fuel additive compounds, with two objectives involving, (1) to examine the effect of heat input (as voltage) and reaction/residence time; and (2) to evaluate the effect of the plastic waste …

Uncoupling Fermentative Synthesis Of Molecular Hydrogen From Biomass Formation In Thermotoga Maritima, Raghuveer Singh, Derrick White, Yaşar Demirel, Robert Kelley, Kenneth Noll, Paul H. Blum

Department of Chemical and Biomolecular Engineering: Faculty Publications

When carbohydrates are fermented by the hyperthermophilic anaerobe Thermotoga maritima, molecular hydrogen (H₂) is formed in strict proportion to substrate availability. Excretion of the organic acids acetate and lactate provide an additional sink for removal of excess reductant. However, mechanisms controlling energy management of these metabolic pathways are largely unexplored. To investigate this topic, transient gene inactivation was used to block lactate production as a strategy to produce spontaneous mutant cell lines that overproduced H₂ through mutation of unpredicted genetic targets. Single-crossover homologous chromosomal recombination was used to disrupt lactate dehydrogenase (encoded by ldh) with …

Membrane-Based Separation Processes For Treating High Salinity Produced Waters, Kamyar Sardari

Graduate Theses and Dissertations

Produced waters (PW) generated in the oil and gas industry within the United States often contain extreme levels of total dissolved solids (TDS). These high TDS waste streams need to be treated cost-effectively as the costs associated with the current management techniques can exceed 15 USD per barrel of discharged PW. Thermally and osmotically-driven membrane separation technologies can show promising potential for treating high TDS waste streams, as onsite low-grade waste heat may be used for their operation. In this dissertation, the application of membrane distillation (MD), forward osmosis (FO) and a hybrid FO-MD process for treating synthetic and actual …

Design Of Peptoid-Based Coating To Reduce Biofouling In Gas Exchange Devices, Neda Mahmoudi

Graduate Theses and Dissertations

In recent decades, membrane technology has been used commonly in biomedical area. However, membrane fouling is a widespread problem in different applications. One method to minimize fouling is through surface modification of membranes. My research explores a novel polymer to minimize nonspecific protein adsorption in biomedical applications.

It firstly focuses on grafting the electrically neutral NMEG peptoid, containing 2-methoxyethyl side chains, to polysulfone (PSU) membrane via polydopamine. Contact angle measurements indicated that the hydrophilicity of the peptoid-grafted membranes was significantly improved while the pore size and strength of the membranes remained unchanged. The modified membranes showed an improved fouling resistance …

Effect Of Differences In The Primary Structure Of The A-Chain On The Aggregation Of Insulin Fragments, Paul P. Nakka, Ke Li, Daniel Forciniti

Chemical and Biochemical Engineering Faculty Research & Creative Works

Bovine and human insulin have similar primary structures. In this article, the region of the insulin A-chain of bovine and human insulin where the amino acid composition is different was studied. Bovine insulin fragment (BIF) and human insulin fragment (HIF) were synthesized in solid-phase peptide synthesis. The effects of pH, temperature, urea, ionic strength, and stirring on the formation of fibrils were studied using a fractional factorial resolution III experimental design. Fibrillation was monitored by fluorescence and infrared spectroscopy and optical microscopy. Both fragments formed fibrils at pH 1.6 and a temperature of 60 °C. The lag time and apparent …

Electrocatalytic Properties Of Ni-Fe Basedalloys Toward Oxygen Evolution Reaction, Xiaodan Cui

LSU Doctoral Dissertations

In this dissertation, laser-based manufacturing was applied to develop NiFe-based alloys, with focus on their electrochemical characteristics toward oxygen evolution reaction during water electrocatalysis. The targeted electrocatalysts were designed by combining catalysis principles of absorption energy, electronic effect and geometry effect. Firstly, a one-step laser-based manufacturing method was applied to prepare a thin layer of NiFe-based electrodes with varied Ni to Fe ratios to replace high-cost noble metals as the electrocatalyst for oxygen evolution reaction (OER). Since each Ni has 0.6 d-vacancy and each Fe atom has 2.2 d-vacancies. The alloying of Ni-Fe allows electrons flowing from Ni to Fe, …

Incorporating Germanium Oxide Into The Glass Phase Of Novel Zinc/Magnesium-Based Gpcs Designed For Bone Void Filling: Evaluating Their Physical And Mechanical Properties, Basel A. Khader, Omar Rodriguez, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

The structural role of Germanium (Ge), when substituting for Zinc (Zn) up to 8 mol % in the 0.48SiO₂-0.12CaO-0.36ZnO-0.04MgO glass series, was investigated with respect to both the glass chemistry and also the properties of glass polyalkenoate cements (GPCs) manufactured from them. The Network connectivity (NC) of the glass was calculated to increase from 1.83 to 2.42 with the addition of GeO₂ (0-8 mol %). Differential thermal analysis (DTA) results confirmed an increase in the glass transition temperature (T_g) of the glass series with GeO₂ content. X-ray photoelectron spectroscopy (XPS) showed an increase in …

Data-Based Nonlinear Model Identification In Economic Model Predictive Control, Laura Giuliani, Helen Durand

Chemical Engineering and Materials Science Faculty Research Publications

Many chemical/petrochemical processes in industry are not completely modeled from a first-principles perspective because of the complexity of the underlying physico-chemical phenomena and the cost of obtaining more accurate, physically relevant models. System identification methods have been utilized successfully for developing empirical, though not necessarily physical, models for advanced model-based control designs such as model predictive control (MPC) for decades. However, a fairly recent development in MPC is economic model predictive control (EMPC), which is an MPC formulated with an economics-based objective function that may operate a process in a dynamic (i.e., off steady-state) fashion, in which case the details …

Reverse Flotation Separation Of Fluorite From Calcite: A Novel Reagent Scheme, Jianjun Wang, Zihan Zhou, Yuesheng Gao, Wei Sun, Yuehua Hu, Zhiyong Gao

Michigan Tech Publications, Part 1

Fluorite (CaF₂), as an important strategic mineral source, is usually separated from calcite by the common froth flotation method, but this separation is still not selective enough. The development of a selective collector and/or depressant is the key to achieving high selective separation. 1-Hydroxyethylidene-1,1-diphosphonic acid (HEDP or H₄L) is widely used as an environmentally friendly water treatment reagent due to its low cost and excellent anti-scaling performance in an aqueous solution. In this study, a novel reagent scheme was developed using HEDP as a fluorite depressant and sodium oleate (NaOL) as a calcite collector for the …

Diverse Lignocellulosic Feedstocks Can Achieve High Field‐Scale Ethanol Yields While Providing Flexibility For The Biorefinery And Landscape‐Level Environmental Benefits, Yaoping Zhang, Lawrence G. Oates, Jose Serate, Dan Xie, Edward Pohlman, Yury Bukhman, Rebecca Garlock Ong, Et Al.

Department of Chemical Engineering Publications

Increasing the diversity of lignocellulosic feedstocks accepted by a regional biorefinery has the potential to improve the environmental footprint of the facility; harvest,storage, and transportation logistics; and biorefinery economics. However, feedstocks can vary widely in terms of their biomass yields and quality characteristics (chemical composition, moisture content, etc.). To investigate how the diversity of potential biofuel cropping systems and feedstock supply might affect process and field‐scale ethanol yields, we processed and experimentally quantified ethanol production from five different herbaceous feedstocks: two annuals (corn stover and energy sorghum) and three perennials (switchgrass, miscanthus, and mixed prairie). The feedstocks werepretreated using ammonia …

Tio2 Assisted Photodegradation For Low Substrate Concentrations And Transition Metal Electron Scavengers, Hassan A. Alsaud, Ahmed E. Abibat, Roger Painter, Lonnie Sharpe, Samuel Keith Hargrove

Mechanical and Manufacturing Engineering Faculty Research

Some contaminants of emerging concern (CECs) are known to survive conventional wastewater treatment, which introduces them back to the environment, allowing them to potentially cycle into drinking water. This is especially concerning because of the inherent ability of some CECs to induce physiological effects in humans at very low doses. Advanced oxidation processes (AOPs) such as TiO2-based photocatalysis are of great interest for addressing CECs in aqueous environments. Natural water resources often contain dissolved metal cation concentrations in excess of targeted CEC concentrations. These cations may significantly adversely impact the degradation of CECs by scavenging TiO2 surface generated electrons. Consequently, …

Rates Of Cavity Filling By Liquids, Dongjin Seo, Alex M. Schrader, Szu-Ying Chen, Yair Kaufman, Thomas R. Cristiani, Steven H. Page, Peter H. Koenig, Yonas Gizaw, Dong Woog Lee, Jacob N. Israelachvili

Faculty Publications

Understanding the fundamental wetting behavior of liquids on surfaces with pores or cavities provides insights into the wetting phenomena associated with rough or patterned surfaces, such as skin and fabrics, as well as the development of everyday products such as ointments and paints, and industrial applications such as enhanced oil recovery and pitting during chemical mechanical polishing. We have studied, both experimentally and theoretically, the dynamics of the transitions from the unfilled/partially filled (Cassie–Baxter) wetting state to the fully filled (Wenzel) wetting state on intrinsically hydrophilic surfaces (intrinsic water contact angle < 90°, where the Wenzel state is always the thermodynamically favorable state, while a temporary metastable Cassie–Baxter state can also exist) to determine the variables that control the rates of such transitions. We prepared silicon wafers with cylindrical cavities of different geometries and immersed them in bulk water. With bright-field and confocal fluorescence microscopy, we observed the details of, and the rates associated with, water penetration into the cavities from the bulk. We find that unconnected, reentrant cavities (i.e., cavities that open up below the surface) have the slowest cavity-filling rates, while connected or non-reentrant cavities undergo very rapid transitions. Using these unconnected, reentrant cavities, we identified the variables that affect cavity-filling rates: (i) the intrinsic contact angle, (ii) …

Catalysts For Nitrogen Reduction To Ammonia, Royce D. Duda, Julie N. Renner

Faculty Scholarship

The production of synthetic ammonia remains dependent on the energy- and capital-intensive Haber-Bosch process. Extensive research in molecular catalysis has demonstrated ammonia production from dinitrogen, albeit at low production rates. Mechanistic understanding of dinitrogen reduction to ammonia continues to be delineated through study of molecular catalyst structure, as well as through understanding the naturally occurring nitrogenase enzyme. The transition to Haber-Bosch alternatives through robust, heterogeneous catalyst surfaces remains an unsolved research challenge. Catalysts for electrochemical reduction of dinitrogen to ammonia are a specific focus of research, due to the potential to compete with the Haber-Bosch process and reduce associated carbon …

Modeling Soot Formation From Solid Complex Fuels, Alexander J. Josephson, Rod R. Linn, David O. Lignell

Faculty Publications

A detailed model is proposed for predicting soot formation from complex solid fuels. The proposed model resolves two particle size distributions, one for soot precursors and another for soot particles. The precursor size distribution is represented with a sectional approach while the soot particle-size distribution is represented with the method of moments and an interpolative closure method is used to resolve fractional methods. Based on established mechanisms, this model includes submodels for precursor coagulation, growth, and consumption, as well as soot nucleation, surface growth, agglomeration, and consumption. The model is validated with comparisons to experimental data for two …

Photocatalytic Carbon Dioxide Conversion To Fuel For Earth And Mars, Anne J. Meier

USF Tampa Graduate Theses and Dissertations

As far as we know, we only have one planet to live on, with a delicate atmospheric system providing us safety and life. Global CO2 emissions continue to plague the environment of Earth, primarily due to the processing of fossil fuels, deforestation, and industrialization. There are several avenues of pursuing CO2 reutilization, each having their own benefits and limitations. Direct and indirect thermochemical approaches of CO2 conversion boast of efficient CO2 conversion rates but have limitations associated with the use of renewable hydrogen and high temperatures of operation. The work in this dissertation investigates low temperature photocatalytic CO2 conversion, a …

Texas Sour Orange Juice Used In Scaffolds For Tissue Engineering, Mandana Akia, Nataly Salinas, Cristobal Rodriguez, Robert Gilkerson, Luis A. Materon, Karen Lozano

Mechanical Engineering Faculty Publications

Fine fibers of polyhydroxybutyrate (PHB), a biopolymer, were developed via a centrifugal spinning technique. The developed fibers have an average diameter of 1.8 µm. Texas sour orange juice (SOJ) was applied as a natural antibacterial agent and infiltrated within the fibrous membranes. The antibacterial activity against common Gram-positive and Gram-negative bacteria (Staphylococcus aureus and Escherichia coli, respectively) was evaluated as well as cell adhesion and viability. The PHB/SOJ scaffolds showed antibacterial activity of up to 152% and 71% against S. aureus and E. coli, respectively. The cell studies revealed a suitable environment for cell growth and cell attachment. The outcome …

Pressure Swing Adsorption Separation Of H2s/Co2/Ch4 Gas Mixtures With Molecular Sieves 4a, 5a, And 13x, Howell H. Heck, Merilyn L. Hall, Rudy Dos Santos, Manolis M. Tomadakis

Mechanical and Civil Engineering Faculty Publications

Pressure swing adsorption experiments were carried out for the separation of equimolar mixtures of carbon dioxide and methane containing small amounts of hydrogen sulfide, utilizing 4A, 5A, and 13X molecular sieves. High-purity methane of zero or nearly zero hydrogen sulfide concentration was produced in the adsorption stage with 13X and 5A sieves, at high product recovery rates; high-purity carbon dioxide was obtained with the same sieves in the desorption stage. Zeolite 4A was found capable of raising considerably the hydrogen sulfide concentration in the accumulated desorption product (vs. the adsorption feed) at high recovery rates too. Adsorption selectivity values derived …