Engineering Commons^™

Thermal, Electrical, And Spin Transport: Encompassing Low-Damping Ferromagnets And Antiferromagnetic/Ferromagnetic Heterostructures, Matthew Ryan Natale

Electronic Theses and Dissertations

Continuing technological advancements bring forth escalating challenges in global energy consumption and subsequent power dissipation, posing significant economic and environmental concerns. In response to these difficulties, the fields of thermoelectrics, spintronics, and spincaloritronics emerge as contemporary solutions, each presenting unique advantages. Thermoelectric devices, based on the Seebeck effect, other a passive, carbon-free energy generating solution from waste heat. Although current thermoelectric technology encounters hurdles in achieving optimal efficiencies without intricate designs or complex materials engineering, recently research into low-damping metallic ferromagnetic thin films have provided a new method to enhance spin wave lifetimes, thus contributing to thermoelectric voltage improvements. As …

Carbon Dioxide Gasification Of Biochar: A Study On Utilizing Captured Co2 To Mitigate Greenhouse Gas Emission And Improving Carbon Conversion Efficiency, Nnamdi Ofuani

Electronic Theses and Dissertations

With rapidly growing global economies and world population, fossil fuel continues to play a major role in meeting current energy demands. Carbon capture and storage (CCS) technologies have, hence, been implemented to reduce CO₂ emissions in the atmosphere. With the implementation of CCS technologies comes the need to utilize the captured CO₂. This research, therefore, proposes CO₂ gasification of biochar as a viable carbon utilization pathway. With captured CO₂ coming at various concentrations, there is a need to understand how CO₂ concentration affects biochar conversion to useful products. This study, therefore, evaluates the effects …

Advances In Cellulose Nanomaterial-Based Foams For Environmental Applications, Md Musfiqur Rahman

Electronic Theses and Dissertations

The use of metal-oxide nanoparticles adsorbents is limited to fixed-bed columns in industrial-scale water treatment applications. This limitation is commonly attributed to the tendency of nanoparticles to aggregate, the use of non-sustainable and inefficient polymeric resins as supporting materials, or a lack of adsorption capacity. Foams and aerogels derived from cellulose nanomaterials have unique characteristics, such as high porosity and low density, which enables their use in a variety of environmental applications, including water treatment. However, the overall use of cellulose nanomaterial-based foams in various environmental sectors is limited due to the high cost of production associated with time- and …

Estimation Of Wood Pulp Fiber Species Composition From Microscopy Images Using Computer Vision, Tyler Seekins

Electronic Theses and Dissertations

Pulp mills and papermakers require careful control of input raw materials. The paper pulp composition, consisting of blends of different wood fiber types, affects multiple final product properties in interacting ways and impacts process operating conditions. Manual estimation of composition by classification and counting using microscopy is time consuming, repetitive, error-prone, and fibers are not always identifiable. Using a dataset of 359,840 fibers from 12,690 images of either hardwood or softwood fibers from 423 microscopy slides with data partitioned into 60% training, 20% validation, and 20% testing splits by slide, and a sequence of principal components analysis, Gaussian mixture, image …

The Development Of An Advanced Biorefinery To Produce Cellulosic Sugars And Bionanomaterials, Carlaile Fernanda De Oliveira Nogueira

Electronic Theses and Dissertations

Market trends show growing interest in cellulose nanomaterials due to their low environmental impact. However, current nanocellulose isolation technologies face technoeconomic and life cycle limitations. Previous research has shown that enzymatic treatments effectively reduce the energy input for mechanical nanocellulose isolation. Simultaneously, there is potential to improve the viability of cellulosic ethanol facilities by coproducing nanocelluloses as high-value product obtained from agricultural feedstock. Here, our goal was to study the mass balance of enzymatic-mechanical processes that coproduces cellulosic sugars and nanocelluloses, evaluating the technical feasibility of converting lignified and non-lignified materials.

First, we have determined a feasible 50:50 mass ratio …

Use Of Photo Isomers To Enhance The Removal Of Lignin From Woody Biomass Hydrolysate, Dipesh J. Karki

Electronic Theses and Dissertations

In this investigation we propose a novel method to enable precipitation of desired solutes using photo-isomers in the extraction solvent. This photo-switchable solvent would enable dissolution or precipitation of desired components using alternating UV or visible light to modify the solubility of the compounds of interest. Three photo-isomers namely native azobenzene, diethoxy azobenzene and diethylamino azobenzene were studied in three different organic solvents: medium chain length alcohol, ethanol and acetone. It was found that among the different combinations of solvent and photo-isomer, acetone and the 4,4’-diethoxy azobenzene solution was most efficient at precipitating dissolved lignin in response to UV light …

Measuring Of Thermal Conductivity And Heat Capacity Of Different Papers And Heat-Sealing Process Of Papers With A Polymer Layer, Amenah Khalaf

Electronic Theses and Dissertations

Packaging is an important and safe way to protect our food and other things through transportation, but the use of plastic based packaging is causing issues with plastic pollution. To replace plastic packaging with a paper-based option that has a barrier coating, good heat sealing will be needed to be a drop-in replacement. While much as been studied on the heat sealing of polymer layers, little has been reported around the heat sealing of paper that has a polymeric barrier coating.

Experiments were conducted to characterize the thermal conductivity and heat capacity of paper as a function of press pressure …

Novel Breath Collection Techniques For Detection Of Covid-19., James Morris

Electronic Theses and Dissertations

Volatile Organic Compounds (VOC) generated endogenously in the human body can be used to detect diseases that induce oxidative stress and inflammation. Breath analysis has been used for the detection of diseases such as COPD, Depression, Lung Cancer and most recently COVID-19. Methods such as Exhaled Breath Condensate (EBC), Sorbent Tubes, Solid Phase Microextraction (SPME), and silicon microreactors have shown considerable capability in extracting and concentrating trace VOC’s present in human breath. Silicon microreactors functionalized with capture agents to derivatize carbonyl compounds are effective but the overall maximum flow rate of breath sample possible during analysis is low, making direct …

Addition Of Process Control Experiment To Unit Operations Ii Laboratory., Bradley Esselman

Electronic Theses and Dissertations

Process control is an essential aspect of manufacturing, contributing to improved process safety, efficiency, product consistency, and energy optimization. Chemical engineers are often responsible for ensuring the safe, efficient, and cost-effective operation of industrial processes, and process control plays a pivotal role in accomplishing this.

Chemical engineering students at the University of Louisville complete the course, Elements of Process Control, during the second semester of their fourth year. This lecture-based course offers limited hands-on, practical experience. To supplement the lack of hands-on experience in the classroom, a new process control experiment was designed and implemented into the Unit Operations …

Efficient Sintering Of Lunar Soil Using Concentrated Sunlight, Diprajit Biswas

Electronic Theses and Dissertations

Construction material is one crucial need for long-term habitation on the moon. When concentrated for high heat flux, solar radiation can heat lunar soil or regolith until it sinters at temperatures above 900°C. The solid, sintered soil simulant can be used as construction material. This work explores the conditions leading to effective lunar soil sintering for both direct and indirect irradiated sintering. Lunar soil simulants were sintered using concentrated light from a xenon-arc lamp with varying heat flux intensity. During direct sintering of LHS-1, a sintering range of 860°C-1140°C corresponding to a peak heat flux of 105-120 kW/m2 was identified …

The Influence Of Pre Coating Layers On Barrier Coatings, Kritee Pokharel

Electronic Theses and Dissertations

Layers of cellulose nanofibrils (CNF) on paper have been demonstrated to be an effective barrier against oxygen and grease and have been shown to improve the barrier performance of dispersion-based barrier coatings. The potential to produce paper grades that have good oxygen, grease, and moisture barrier properties is clear, but a good understanding of the synergies between CNF, other coating layers, and water-borne barrier coatings (WBBC) is not clear. Different coat weights of a WBBC were applied to papers that have a range of different qualities and amounts of the CNF layer on them. The same WBBC was also applied …

Investigation Of Pulsed Electrolysis For Hypochlorous Acid Production, Khoa V. Kieu

Electronic Theses and Dissertations

Because of the Covid-19 pandemic along with the delay in the worldwide supply chain, there were disinfectant shortages that lasted for weeks around the world. Therefore, on-site production is a promising solution to satisfy the increasing demand. As more and more people are shifting toward safer and more environmentally friendly products, we are interested in investigating the electrolysis of sodium chloride (NaCl) solution to produce hypochlorous acid (HOCl). Electrolysis is inexpensive as it requires only sodium chloride and electricity, and it does not have any negative impact on the environment. Moreover, electrolysis can be coupled with renewable energy to utilize …

Solid Acid Catalyzed Dehydration Reactions Of Biomass-Derived Alcohols, Mackenzie Todd

Electronic Theses and Dissertations

Concerns around climate change and the use of fossil resources contributing to increasing carbon dioxide concentrations in the atmosphere has motivated transitions to use biomass resources for the production of specialty chemicals and fuels, in hopes of creating a more cyclical use of carbon. The work presented here focuses on two different aspects of catalytic upgrading of biomass-derived platform molecules using heterogeneous acid catalysts. First, we use an interdisciplinary and iterative approach to process development for producing a diesel fuel additive from pyrolysis oils of woody biomass. We use fuel property calculations to define measures of success in chemical upgrading …

Disinfection Applications Of On-Site Hypochlorous Acid Production, Deborah Ngabanyi Sebagisha

Electronic Theses and Dissertations

Hypochlorous acid (HOCl) is a weak acid, but strong oxidizing agent produced naturally in the human body to fight viruses and bacteria. Hypochlorous acid can be produced by electrolysis of sodium chloride and water enabling local production of disinfectant, where it is needed. Hypochlorous acid has many applications including in wound care, skin care, and disinfection of health and dental clinics. In this work, two hypochlorous acid applications were explored that could utilize local production by electrolysis. These applications were wastewater treatment and sanitization of dental operating rooms.

An electrochemical reactor and process were designed, constructed, and tested for hypochlorous …

The Influence Of Heat And Mass Transfer On The Setting Rate Of Adhesives Between Porous Substrates, Mubarak Mohammed Khlewee

Electronic Theses and Dissertations

The dynamic penetration of fluid into a porous media where other changes are occurring such as temperature or concentration is of interest to a number of situations. However, little experimental and theoretical analysis of this situation is found in the literature where most of the previously published works have studied the penetration with constant physical properties, where there is no change of the fluid as it enters the pores. This situation is important in the setting of adhesives in porous medium such as in the setting of hot melt and water-based adhesives in the production of paper based packaging. The …

The Study Of Corrosion On Additive-Manufactured Metals., Braydan Daniels

Electronic Theses and Dissertations

The purpose of this study was to investigate and compare the corrosion mechanisms between wrought and additive-manufactured (3D-printed) copper and stainless steel. The experimental procedure consisted of measuring the open circuit potential, electrochemical impedance spectroscopy, linear sweep voltammetry, Tafel analysis, surface topology, and scanning electron microscopy for each metal within salt water, tap water, sulfuric acid, and synthetic body fluid (excluding copper in synthetic body fluid).

Overall, printed stainless steel was more corrosion-resistant than wrought stainless steel in tap water and synthetic body fluid based on OCP, LSV, and surface topology results. Additionally, printed copper was more corrosion-resistant than wrought …

Novel Microdevices To Analyze Toxic Volatile Organic Compounds., Sujoy Halder

Electronic Theses and Dissertations

There has been a growing interest to measure volatile organic compounds (VOCs) in a range of environmental applications. The presence of toxic VOCs in the air has been associated with serious health problems including asthma, central nervous system dysfunction, cardiovascular disease and cancer, etc. Different analytical instruments such as gas chromatography-mass spectrometry (GC-MS) and sensor systems, such as metal oxide sensors are used to analyze VOCs. However, challenges still exist in the detection of airborne VOCs because of their trace concentration and interference with complex gas mixtures. In this dissertation, two microfabricated devices, a sensor array and a micropreconcentrator were …

Investigation Of Light Management Strategies And Photochemistry Of Si/Tio2 Tandem Microwire Slurries For Solar Hydrogen Generation., Saumya Gulati

Electronic Theses and Dissertations

The intermittent nature of the Sun makes it difficult to use it as a primary source of electricity and often needs to be supplemented by electricity from the grid which comes from fossil fuels. This motivates the need for solar energy storage. Photoelectrochemical (PEC) water-splitting has been explored as a means to convert solar energy into hydrogen (and oxygen), which can be stored as fuel. The current method of coupling PV and electrolyzer units has been widely commercialized, however, the cost of H₂ generated is far from the target of $1/kg set by the DOE under the Energy EarthShot …

Synthesis, Property Tuning And Degradation Studies Of Phosphorene-Based Materials., Usman Onuminya Abu

Electronic Theses and Dissertations

Two-dimensional (2D) layered materials have sparked the interest of researchers because of their interesting properties drawn from quantum confinement effects, elevated density of states (DOS), increased surface area, increased active sites, etc. Phosphorene, an interesting addition to the 2D material family in 2014, has interesting properties such as in-plane anisotropy, elevated carrier mobility and thickness-dependent bandgaps that have made it a material of intense interest. Furthermore, there have been theoretical studies predicting that phosphorene could be made even more versatile by intercalating alkali atoms into its layers. Intercalation has proven to be a veritable tool for synthesis, modification, transformation, and …

Chloramine Devulcanization Of Waste Rubber., Patrick Kroeger

Electronic Theses and Dissertations

The disposal of waste rubber, particularly tire rubber, continues to pose a challenge in the 21st century. As a result, most end-of-life tires (ELTs) are either dumped in landfills or burned as tire-derived fuel. Chloramine devulcanization may offer a viable solution to this problem. Chloramine devulcanization is a low-temperature, low-pressure, process that selectively breaks sulfur crosslinks while preserving the polymer backbone. Chloramine devulcanization enables the recovery of chloramine recovered carbon black (CrCB) and devulcanized rubber (CdR) as separate products. Initial analysis of CdR revealed that it was formable and malleable, suggesting that crosslinking was absent. Spectroscopy showed that CdR contained …

Compositional Engineering Of Precursor Inks For Intense Pulsed Light Compatible Deposition Of Perovskite Solar Cells., Blake Martin

Electronic Theses and Dissertations

Perovskite solar cell (PSC) technology offers a promising alternative to silicon-based photovoltaics (PVs), but challenges of stability, module efficiency, and scalability hinder commercialization. This study aims to explore potential solutions to overcome scalability and cost limitations of PSCs, addressing technical barriers to commercialization. We adapt the conventional three-stage perovskite deposition process (deposition, translational phase formation, and annealing) for scalable platforms using wide-area depositions, meniscus coating methods, forced laminar airflow drying, and radiative annealing methods, making it more suitable for roll-to-roll fabrication. A technoeconomic analysis shows that large-scale operations can produce solar films at a cost of $0.04-$0.10 per watt, making …

Detection Of Toxic Aldehydes In Aerosols Of Electronic Cigarettes., Ellie Bess Reed

Electronic Theses and Dissertations

Over the past decade, use of electronic cigarettes (e-cigarettes) has increased in the younger generations of the United States. With the broad range of flavors and devices distributed on the market, American youth are prime marketing targets for the e-cigarette industry. To create a more regulated market, research of this thesis has been conducted on newer generations of e-cigarette “MOD” devices to examine how e-cigarette battery power output and coil temperature, concentrations of propylene glycol and vegetable glycerin, added flavorings (strawberry, mango, and menthol), and the presence of nicotine affect generation of aerosol particles and aldehydes in aerosols emitted by …

An Experimental Study On The Mechanical Properties And Chemical Composition Of Lcd 3d Printed Specimens, Sebastian Gomez

Electronic Theses and Dissertations

Additive manufacturing technologies have been enhanced throughout the years yet have surprised the manufacturing industry due to their high-end surface finish and dimensional accuracy. Different experiments have been done to identify a specific phenomenon known in the vat-polymerization field. Distortion and dimensional inaccuracy tend to affect the overall properties of the process, either physical or chemical. This approach allows the understanding of how the physical properties have been affected and how to study the chemical properties to avoid this type of phenomenon. The chemical reaction between polymer and UV light has been studied and experimented with to the point that …

Evaluating The Impact Of Increased Cycling On Thermal Power Plants Due To Wind Energy Penetration In The Midwest: A Case Study, Joscelyne Larson

Electronic Theses and Dissertations

One of the most significant shifts in the mix of U.S. electricity generation over the past few years has been the rapid expansion of renewable energy resources, especially solar and wind. However, fossil fuels are still necessary to fulfill the world’s energy requirements. Despite efforts to increase the use of renewable energy sources, these sources can be at times unreliable, causing countries around the world to continue to rely on base load units such as coal and natural gas. This decrease in fossil fuels and increase in renewable energy sources presents many complex issues in terms of power system planning, …

Investigations Of A Surrogate Fuel Based On Fischer-Tropsch Gtl And Ctl In Cvcc, Idi And Di Compression Ignition Engines, Amanda C. Weaver

Electronic Theses and Dissertations

With the increase in availability, feedstocks, and properties of alternative fuels, compatibility issues emerge between current engine platforms often requiring a limit on the blend percentage of alternative fuel in conventional fuel or alteration to the engine platform. Two key metrics were identified, autoignition quality and lubrication characteristics, as vital for the proper function of a compression ignition engine, and if the blend of alternative fuels matches these two criteria for the diesel standard, then the resulting blend percentage can be considered as a viable alternative for complete replacement of conventional petroleum ULSD. Autoignition quality was matched using blends S-8, …

Operation And Preliminary Energy Balance Of A Portable Kelp Dryer In Maine, Tuqa Al-Asadi

Electronic Theses and Dissertations

Seaweed (macroalgae) is a marine resource that has a high economic value. Seaweeds are important commodities as raw material for food or additives and as a source of biomass. One popular species of seaweed is Sugar kelp (Saccharina latissima) – a brown algae that is native to the Maine coast and also a commonly farmed species. It is a rich source of fibers, vitamins, minerals, and antioxidants. Seaweeds are highly perishable due to their high moisture content and will spoil quickly if not preserved, therefore a common practice is to dry the product to prolong storage life and to minimize …

Anion Alloying Of Iii-V Semiconductors For Water Splitting., Sonia Calero-Barney

Electronic Theses and Dissertations

The challenge of solar energy conversion and storage translates into the discovery and development of semiconductor materials that can transform sunlight energy into electricity and/or high-energy-density fuels in a cost-effective way. From the solar energy conversion perspective, cation-alloyed III-V solar cells hold record-breaking energy conversion efficiencies, while anion-alloyed III-V’s are particularly interesting for photoelectrochemical hydrogen generation. The major challenge for the adoption of III-V-based technologies lies in the high manufacturing costs of established synthesis techniques and the difficulty to control the composition of ternary alloys. One of the materials investigated in this work is GaSb_zP_1-z. Thermodynamic …

Biobased Packaging Materials From Cellulose Nanofibrils Produced From Virgin Wood Pulp Or Recycled Cardboard Pulp, Md Ikramul Hasan

Electronic Theses and Dissertations

Self-standing cellulose nanofibril (CNF) films are regarded as one of the promising alternatives to current petroleum-based packaging materials. The mechanical and barrier properties of CNF films are not yet up to the mark for certain applications, especially at high relative humidity. Those properties of CNF films can be tuned by the drying methods of films, degree of fibrillation, cross-linking, and controlled shrinkage. A comprehensive understanding of these processes and their influence on the structure and properties of CNF films have been presented in this thesis.

First, we prepared CNF films from CNF suspensions with two different degrees of fibrillation- standard …

Contact Dewatering Of Cellulose Nanofibers For Biopolymer Composite Applications, Alexander Collins

Electronic Theses and Dissertations

Cellulose Nanofibrils (CNFs) are promising materials for reinforcement of polymer matrices attributable to their impressive physical and mechanical properties, as well as their biodegradability. However, the utilization of these materials in composites is made challenging by the water content of CNF slurries, the tendency of CNFs to agglomerate as they dry, and incompatibility between hydrophilic CNFs and hydrophobic polymer matrices. The most commercially viable drying methods to produce small-scale dry CNFs, such as spray drying, are very energy intensive, can only dry the materials down to micron-scale agglomerates, and do not preserve fibrillar aspect ratios. “Contact dewatering,” or the removal …

Intersections Of Environmentalism, Chemistry, And Racism: An Experimental Study Of Halobenzene Hydrogenolysis And Critical Communication Studies Of Equitable Learning Practices Rooted In Black Feminism, Lauren O. Babb

Electronic Theses and Dissertations

Increasing concentrations of fluorinated aromatic compounds in surface water, groundwater, and soil pose threats to the environment. Fundamental studies that elucidate mechanisms of dehalogenation for C-X compounds (where X represents a halide) are required to develop effective remediation strategies. For halogenated benzenes, previously published research has suggested that the strength of the C-X bond is not rate-determining in the overall rate of dehalogenation. Instead, the rate-determining step has been hypothesized to be adsorption of the C-X compound onto the surface of a catalyst. Building on this hypothesis, in this work, we examine the reaction kinetics of fluorobenzene conversion to benzene, …