Engineering Commons^™

Exploring Soil Microbial Dynamics In Southern Appalachian Forests: A Systems Biology Approach To Prescribed Fire Impacts, Saad Abd Ar Rafie

Doctoral Dissertations

Prescribed fires in Southern Appalachian forests are vital in ecosystem management and wildfire risk mitigation. However, understanding the intricate dynamics between these fires, soil microbial communities, and overall ecosystem health remains challenging. This dissertation addresses this knowledge gap by exploring selected aspects of this complex relationship across three interconnected chapters.

The first chapter investigates the immediate effects of prescribed fires on soil microbial communities. It reveals subtle shifts in porewater chemistry and significant increases in microbial species richness. These findings offer valuable insights into the interplay between soil properties and microbial responses during the early stages following a prescribed fire. …

Prove Primary Battery Structure, John D. Burkhart, Andy Mccormick, Ryan Yu, Soren Barclay

Mechanical Engineering

In conjunction with Prototype Vehicle (PROVE) Laboratory, our group designed, manufactured, and tested a prototype structure to house the battery boxes for PROVE’s endurance vehicle. Our structure was designed to support the batteries during normal use, and in the event of a front crash. Our design is comprised of a secondary composite box to house the battery boxes, a bottom plate to affix the secondary box to the chassis floor, a horizontal plate fastened to the chassis, and a brace structure welded to the chassis. From the outset, we chose to use a secondary box, the primary battery boxes must …

The Effects Of Carbon Coating On The Electrochemical Performance Of Metal-Oxide Short Fiber Anodes For Lithium-Ion Batteries, David A. Sanchez

Theses and Dissertations

This thesis focuses on the process of oxidizing centrifugally spun precursor fibers and the subsequent process of carbon coating via chemical vapor deposition (CVD) for use as anode material in lithium-ion batteries (LIBs). Metal oxides have been studied as a potential replacement for graphite as they have been shown to have high theoretical capacities, good electronic conductivity, and can be synthesized using low-cost, scalable methods. However, metal oxides with high theoretical capacities also have low cycle life. To avoid this, metal oxides have been integrated with carbon to expand their life cycle. The work in this thesis shows the synthesis …

Battery Design, Construction, And Characterization For Small Motor Use Focusing On Anodic Zinc For Electron Flow, Amber Veach

Chemical Engineering Undergraduate Honors Theses

This thesis explores the construction, characterization, and application of anodic zinc batteries for powering a small electric motor for the ChemE Car competition. Two zinc galvanic cell batteries were studied: zinc-carbon and zinc-air batteries. Prototype batteries were constructed and tested for voltage, amperage, and power production. In the zinc-carbon trials, a 3:1 mixture of manganese dioxide and graphite was determined to be the best cathode for power production. The size which allowed for sufficient power while maintaining the smallest footprint on the car was a zinc can six cm tall and two cm in diameter. Analysis of paper zinc-air battery …

Joining Methods For Continuous Fiber Reinforced Thermoplastic Composites In Structural Applications, Andrew Moran

Electronic Theses and Dissertations

Continuous fiber reinforced thermoplastic (CFRTP) composites have been proposed as an alternative to metals in structural applications. CFRTP composites can be used to create structures that are lighter weight, have better resistance to environmental factors, and have the potential to be recycled. However, one of the main challenges to CFRTP composites is connections between structural members. The goal of this thesis is to investigate the feasibility of joining CFRTP composites to both similar and dissimilar materials through literature review, coupon testing, design of a structural joint, and a small scale laboratory prototype of the joint. To achieve this goal the …

Carbon Fiber Recycling: Delamination System, Aaron Eastman

All Undergraduate Projects

The production of composite wings at Boeing causes carbon fiber waste and CWU Mechanical Engineering Technology students have been tasked in designing a carbon fiber recycling system. This project was brought forth and funded by the Joint Center for Aerospace Technology Innovation (JCATI). There are three subsystems that make up the carbon fiber recycling system, the delamination system, shredding system, and the oven. The purpose of this project was to increase the efficiency and effectiveness of the delamination system of the carbon fiber recycling system. The old system reached approximately 30-40 percent delamination with one pass through the system, and …

Crystal Structure Prediction Of Materials At Extreme Conditions, Ashley S. Williams

USF Tampa Graduate Theses and Dissertations

The prediction of the structure of a crystal given only the constituent elements is one of the greatest challenges in both materials science and computational science alike. If one were to try to predict a novel crystal by brute force, meaning by arranging the atoms in every possible position of the unit cell and optimizing the geometry to find the energy minima of the potential energy surface, the amount of computer resources required to complete the calculation on the timescale of a few years would vastly exceed the currently installed computational capacity of the entire world. Fortunately, several methods have …

Strengthening Of Concrete Deep Beams Using Carbon Fabric Reinforced Cementitious/Geopolymeric Matrix, Nour Mohamed Muhsen Khir Allah

Theses

This research aimed to examine the effectiveness of using carbon fabric-reinforced matrix (C-FRM) composites to improve the shear response of reinforced concrete (RC) deep beams. Ten RC deep beams with a/h of 1.6 were tested, where a is the shear span and his is the beam depth. Test parameters included the presence of internal shear reinforcement (no shear reinforcement and minimum shear reinforcement), number of C-FRM composite layers (one and two layers), angle of inclination of the second layer of CFRM (90o and 0o with respect to the longitudinal direction of the beam), and type of matrix (cementitious and geopolymer). …

Equations Of State For Warm Dense Carbon From Quantum Espresso, Derek J. Schauss

Theses and Dissertations

Warm dense plasma is the matter that exists, roughly, in the range of 10,000 to 10,000,000 Kelvin and has solid-like densities, typically between 0.1 and 10 grams per centimeter. Warm dense fluids like hydrogen, helium, and carbon are believed to make up the interiors of many planets, white dwarfs, and other stars in our universe. The existence of warm dense matter (WDM) on Earth, however, is very rare, as it can only be created with high-energy sources like a nuclear explosion. In such an event, theoretical and computational models that accurately predict the response of certain materials are thus very …

Jcati Pyrolysis System, Jack Dutton

All Undergraduate Projects

The Joint Center for Aerospace Technology Innovation (JCATI) project is designed to recycle carbon fiber pieces for use in manufacturing. Part of the system requires the removal of resin from the carbon fibers to facilitate the recycling of carbon fiber. To accomplish this task the pyrolysis process is implemented using a commercial grade oven with a conveyor system. Argon gas is injected into the shroud and over the oven to purge the interior of oxygen. The conveyor system enables this to be a batch process. A ramp is used to allow simple addition of material to the conveyor system and …

Experimental Analysis Of Heat Generation In Carbon, Mounisha Ganesan

Doctoral Dissertations and Master's Theses

The purpose of this research is to study a novel non-covalent functionalization technique of single-walled carbon nanotubes (SWCNTs) and to examine the feasibility of using carbon nanotube films as thin film heaters. We developed a unique methodology to synthesize a well dispersed, environmentally friendly solution of CNTs that could be easily spin coated as well as spray coated on different substrates based on the application. Using the produced solutions, thin films of SWCNTs were fabricated on a glass substrate. Two sets of experiments were conducted to study the influence of polyaromatic moiety and the pH on the electro thermal characteristics …

Modeling And Effects Of Non-Homogeneous Infiltration On Material Properties Of Carbon-Infiltrated Carbon Nanotube Forests, Daniel Owens Snow

Theses and Dissertations

This work investigates the material properties and production parameters of carbon infiltrated carbon nanotube structures (CI-CNT's). The impact of non homogeneous infiltration and the porosity of cross section regions, coupled with changes in designed geometry, in this case beam width, on the density and modulus of elasticity are compared. Three potential geometric models of beam cross section are proposed and evaluated. 3-point bending, SEM images, and numerical optimization are used to assess the validity of each model and the implications they have for future CI-CNT material applications. Carbon capping near exterior beam surfaces is observed and determined to be a …

Fabrication Of Multifunctional Carbon Coated Cobalt Ferrite Core/Shell Nanostructures By Pulsed Laser Ablation, Joy Roy

MSU Graduate Theses

Considerable research work is going on worldwide among the therapeutic scientific communities to use magnetic nanoparticles (NPs) as a controlled drug delivery system. Challenges to use those NPs for such in-vivo applications successfully are mainly biocompatibility and the functionality of those NPs. Addressing the needs, in this project, we synthesized carbon-coated cobalt ferrite (CFO) core-shell nanoparticles (CSNPS) by ablating a solution of toluene and CFO NPs with varying number of pulsed laser shots. The structure of the CSNPs then investigated through X-ray diffraction (XRD), Raman spectroscopy, and also with the high-resolution transmission electron microscopy (HRTEM). The XRD analysis shows that …

Investigation Of Oxidized Carbon Supported Au Catalysts Synthesized Via Strong Electrostatic Adsorption Of Au(En)2Cl3 For The Hydrochlorination Of Acetylene To Vinyl Chloride Monomer, Sean Reginald Noble

Theses and Dissertations

Over 20 million tons of vinyl chloride monomer (VCM) is produced every year using acetylene hydrochlorination using a supported mercuric chloride catalyst. During this process mercury is reduced and sublimes into the environment harming all living animals and humans, so carbon-supported Au catalysts have been developed in attempts to replace it. Various techniques have been used to make these catalysts including several variations of dry impregnation. In this study we investigate the ability of Strong Electrostatic Adsorption (SEA) of Au(en)₂Cl₃ onto various supports to demonstrate the ability to rationally and consistently synthesize gold catalysts with ultra-small particle …

Brominated Carbon Materials As Positive Electrodes For Nonaqueous Secondary Lithium-Bromine Batteries, Benjamin Beau Peterson

LSU Doctoral Dissertations

Secondary lithium-bromine (Li-Br₂) batteries have theoretical potentials near 4.1 V vs Li/Li⁺ and capacities more than 2 times greater than conventional Li-ion batteries. Herein, secondary, non-aqueous Li-Br₂ half-cell batteries are reported using a Li metal anode, carbon-coated glass fiber separator, non-aqueous Li-based electrolytes with and without the addition of lithium bromine (LiBr) salt, and positive electrodes consisting of either chemically brominated non-graphitic carbon or carbon derived from the carbonization of metal-organic frameworks (MOFs) with LiBr embedded into the micro- and mesopores of the carbon matrix. The separator is effective in mitigating the transport of Br_{2 …}

Novel Methods For Composites Recycling Via Pyrolysis, Matt Jacobs

Undergraduate Honors Theses

Composites are unique materials in many respects. When fabric woven from carbon fibers is joined with a thermoset resin in a controlled environment, it results in a very strong material, especially evaluated on a pound-for-pound basis against metals and ceramics. One aspect of this construction that provides great strength lies in the fiber-matrix adhesion which facilitates load transfer to the reinforcement of the composite. This fiber-matrix adhesion is promoted by the polarity of the usual thermoset matrices, and properly designed sizing materials coating the fibers. It’s a two-edged sword, though. Although the resin and the fibers are quite strong together, …

Economic Efficiency And Carbon Emissions In Mes With Flexible Buildings, Zach Lawrence Hurwitz

Graduate College Dissertations and Theses

Multi-energy systems offer an opportunity to leverage energy conversion processes and temporary energy storage mechanisms to reduce costs and emissions during operation of campuses, cities, and buildings. With increasing options for flexibility in demand-side resources it is possible to meet demand without sacrificing comfort and convenience of MES occupants.

This Thesis develops a multi-period, linear optimization model of an MES with flexible buildings that captures nonlinearities in the efficiency of energy conversion processes. The flexible buildings are parametrized, in part, based on historical data from a college campus in Vermont, USA. The idea of the MES model is to investigate …

Carbon Oxidation At The Atomic Level: A Computational Study On Oxidative Graphene Etching And Pitting Of Graphitic Carbon Surfaces, Simon Schmitt

Theses and Dissertations--Mechanical Engineering

In order to understand the oxidation of solid carbon materials by oxygen-containing gases, carbon oxidation has to be studied on the atomic level where the surface reactions occur. Graphene and graphite are etched by oxygen to form characteristic pits that are scattered across the material surface, and pitting in turn leads to microstructural changes that determine the macroscopic oxidation behavior. While this is a well-documented phenomenon, it is heretofore poorly understood due to the notorious difficulty of experiments and a lack of comprehensive computational studies. The main objective of the present work is the development of a computational framework from …

Laser-Spark Multicharged Ion Implantation System ‒ Application In Ion Implantation And Neural Deposition Of Carbon In Nickel (111), Oguzhan Balki

Electrical & Computer Engineering Theses & Dissertations

Carbon ions generated by ablation of a carbon target using an Nd:YAG laser pulse (wavelength λ = 1064 nm, pulse width τ = 7 ns, and laser fluence of 10-110 J/cm²) are characterized. Time-of-flight analyzer, a three-mesh retarding field analyzer, and an electrostatic ion energy analyzer are used to study the charge and energy of carbon ions generated by laser ablation. The dependencies of the ion signal on the laser fluence, laser focal point position relative to target surface, and the acceleration voltage are described. Up to C⁴⁺ are observed. When no acceleration voltage is applied between …

Effects Of Corrugations On Stiffness Properties Of Composite Beams For Structural Applications, Jane Xiao

Master's Theses

Composites have high strength-to-weight ratios, which is particularly desired for applications with weight restrictions. Common composite materials such as carbon fiber reinforced plastic (CF) and fiber glass reinforced plastic (FG) were used in this research. While composite materials possess high stiffness and strength properties, the stiffness of composite laminates may be maximized by changing the geometry. By adding corrugations, the flexural stiffness is increased in one direction compared to the stiffness of a flat part with the same amount of material. Thus, stiffness increases without a change in weight. The primary goal of this research was to investigate the stiffness …

Exploring The Electrical Properties Of Twisted Bilayer Graphene, William Shannon

Senior Theses

Two-dimensional materials exhibit properties unlike anything else seen in conventional substances. Electrons in these materials are confined to move only in the plane. In order to explore the effects of these materials, we have built apparatus and refined procedures with which to create two-dimensional structures. Two-dimensional devices have been made using exfoliated graphene and placed on gold contacts. Their topography has been observed using Atomic Force Microscopy (AFM) confirming samples with monolayer, bilayer, and twisted bilayer structure. Relative work functions of each have been measured using Kelvin Probe Force Microscopy (KPFM) showing that twisted bilayer graphene has a surface potential …

New Method Of Manufacturing Carbon Foam, Matthew D. Artimez

Graduate Theses, Dissertations, and Problem Reports

Carbon foam is a product that has some unique features. Carbon foam is a light weight material that has a high crush strength. It is electrically conductive, but because it is composed of air space between the tendrils, it is not a thermal conductor. Since it contains no volatile content, it is noncombustible. All these features allow carbon foam to have many modern applications. Currently, there are only three methods of producing carbon foam, and all three are not cost- efficient enough to meet the demand of potential new markets.

In this thesis, a new procedure of producing carbon foam …

Electron Transport In One And Two Dimensional Materials, Samuel William Lagasse

Legacy Theses & Dissertations (2009 - 2024)

This dissertation presents theoretical and experimental studies in carbon nanotubes (CNTs), graphene, and van der Waals heterostructures. The first half of the dissertation focuses on cutting edge tight-binding-based quantum transport models which are used to study proton irradiation-induced single-event effects in carbon nanotubes [1], total ionizing dose effects in graphene [2], quantum hall effect in graded graphene p-n junctions [3], and ballistic electron focusing in graphene p-n junctions [4]. In each study, tight-binding models are developed, with heavy emphasis on tying to experimental data. Once benchmarked against experiment, properties of each system which are difficult to access in the laboratory, …

Development Of Low Cost, Environmentally Friendly And High Strength Carbon Foams From Bread And Cake, Laura Mountain-Tuller

Materials Engineering

Carbon foam is a high niche material that consists of a highly porous, three-dimensional cellular network that is characterized by extremely high strength-to-weight ratios and low thermal conductivity. Due to these properties, carbon foams excel in structural and thermal applications, especially in the aerospace industry. Typically, carbon foams are formed through a heating process called pyrolysis of polymer precursors with high carbon content. This process is done at high temperatures in an oxygen free environment. These precursors are expensive to make and use toxic chemicals to produce, therefore, there is a push to find an environmentally friendly and cost-effective method …

Lead Doped Carbon Nanofibers In Li-Ion Batteries, Omar Torres

Theses and Dissertations

Lead acid batteries have been a very reliable rechargeable battery since its inception in the mid-1800s. Lithium-Ion batteries have been sought out for their light-weight and capacity of holding large amounts of energy in a small amount of space. Few studies have been conducted in the use of lead in lithium-ion batteries.

In this thesis, lead-doped carbon nanofibers were produced by using the Forcespinning® method and used as an anode on a lithium-ion battery. The morphology, material characterization and thermal properties of the anode material were analyzed using the Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Thermogravimetric Analysis …

Wafer Enhanced Electrodeionization For Conversion Of Co2 Into Bicarbonate Feed For Algae Cultured Photobioreactors, Kayvan Afrasiabi

Chemical Engineering Undergraduate Honors Theses

The world has acknowledged climate change as a global crisis that demands considerable attention, with one of the largest culprit being carbon emissions from industrial processing and power generation. While reduction in carbon emissions is the principal action towards mitigating the effects of climate change, scientists and engineers have given increased attention to alternative sources of energy as well as methods of carbon sequestration to coax traditional manufactory and industry into environmentally friendly and sustainable practices. One technology of this nature is the use of wafer-enhanced electrodeionization (WE-EDI) membranes to convert gaseous carbon dioxide (CO₂) from industrial flue …

Evaluating The Impact Of External Carbon Source In Laboratory-Based Denitrification Rate Experiments, Jared Richens

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Limitations in the quality of transformation rates used with water quality models such as QUAL2K have led to the need to identify methods that can effectively and accurately determine these rates. During the early stages of method development of a Utah Department of Environmental Quality (Utah DEQ) funded project seeking to identify such methods, it was determined that under certain situations external carbon amendment may be required to successfully determine denitrification rates.

The focus of this study was to evaluate the potential impacts that introducing external carbon sources may have on estimating the laboratory denitrification rates resulting from these methods. …

Evaluation Of Powdered Activated Carbon For Control Of Taste And Odors Caused By Geosmin, Anthony Joe Rodriguez

Open Access Theses & Dissertations

The primary sources of taste and odor problems associated with surface water supplies spawn from algae and bacterial blooms that secrete odorous chemicals such as Geosmin and MIB. These musty, odorous, organic compounds are usually detectable by the human nose at concentrations of 5 to 10 ppt and can create considerable concern by consumers that can lead to complaints and misconceptions of odors as a water quality problem. Typically, since chemical or ozone treatment can be costly, activated carbon (powdered or granular) is generally employed in the process of removing organic compounds, such as Geosmin and MIB. The research presented …

Hydrodeoxygenation Of Acetic Acid Using Monometallic And Bimetallic Catalysts Supported On Carbon, José Luis Contreras Mora

Theses and Dissertations

Heterogeneous catalytic hydrodeoxygenation (HDO) of biomass-derived feeds is a deoxygenation process that is of highly interest. Carboxylic acids are one of the main components of bio-oils and acetic acid is one of the most abundant of these carboxylic acids. This acid is rich in oxygen, therefore a lot of research to produce fuel and other valuable chemicals such as ethanol is of interest.

This dissertation explores the gas-phase catalytic HDO of AA over catalysts supported on activated carbon (Cp-97). Temperature-dependent conversion and selectivity were studied at 1 atm from 200-400⁰C with an AA concentration of 1.1% and 20% …

Numerical Modeling And Isotope Tracers To Investigate Karst Biogeochemistry And Transport Processes, Admin Husic

Theses and Dissertations--Civil Engineering

This dissertation investigated the physical and biogeochemical processes affecting the source, fate, and transport of sediment, carbon, and nitrogen within a highly-coupled fluviokarst system. Elemental and isotopic datasets were collected at surface and subsurface locations for both dissolved and particulate contaminant phases, new methodology regarding data collection was presented to the karst research community, an in-cave sediment transport model coupling physical transport with elemental and isotopic mass balances of carbon and nitrogen was formulated, pathway and process control on nitrate leaching from agricultural karst watersheds was assessed, and nitrate mobilization and fractionation were modeled using high frequency storm sampling and …