Thermodynamics Commons^™

Ultrafast Laser Surface Structuring For Wettability Control On Copper, Akshay Arvind Nagvenkar

All Theses

Wettability is a crucial surface property influencing various phenomena, including heat transfer, cell adhesion, and corrosion. Engineering devices can achieve superior performance by precisely manipulating surface wettability. As a result, extensive research has focused on developing surfaces that exhibit either extreme water attraction (superhydrophilic) or strong water repellency (superhydrophobic). Tailoring surface wettability paves the way for numerous applications, such as drag reduction in marine vessels, controlled drug delivery, efficient water collection, advanced liquid transport systems, oil-water separation, anti-corrosion coatings, friction reduction, and self-cleaning materials. Ultrafast laser surface structuring is a promising approach for engineering multifunctional surfaces, effectively modifying material properties …

Fabrication And Performance Of Scalable Bio-Engineered Porous Layers For Efficient Co2 Capture, Mary Sharon Rose Bondugula

Theses and Dissertations

This dissertation addresses the critical challenge of mitigating climate change by advancing CO2 capture technologies. As global CO2 emissions continue to rise, effective methods for capturing and separating CO2 from industrial processes are essential to combat climate change. Existing CO2 capture systems, such as Pressure Swing Adsorption (PSA) and Temperature Swing Adsorption (TSA), often rely on packed bed designs that face limitations, including poor heat and mass transfer, slow gas diffusion, and low thermal conductivity, reducing their efficiency. To overcome these challenges, this dissertation explores innovative solutions by developing advanced adsorbent coatings and scalable bed configurations.

This research begins by …

Data-Driven Modeling Of Oxygen Kinetics In La0.6sr0.4co0.2fe0.8o3−Δ (Lscf) For High-Temperature Reduction Of Co2 In An Electrolysis Cell, Ferron Campbell

Graduate Theses, Dissertations, and Problem Reports (ETD)

Electrolysis systems are critical to several societal applications, particularly energy storage and conversion. Developing these systems requires a detailed knowledge of the chemistry and thermodynamics of the materials used in the electrolysis cell. This work focuses on using embedded scientific machine learning as an efficient way to build an interpretable model for the reaction and transport kinetics in the LSCF electrode, whose performance directly influences the electrolysis system’s performance. The models developed in this study are trained using the publicly available machine learning package, FoKL-GP. This package incorporates a robust Gibbs sampler that employs a forward variable selection process to …

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 …

Testing The Effectiveness Of Various Fabrics For Use In Protective Face Coverings, Isaac Daley

Williams Honors College, Honors Research Projects

Facemask requirements have been heavily implemented as a result of the COVID-19 pandemic. The purpose of this study was to test various fabrics that could be used in face coverings and determine which materials are best for reducing virus transmission rates. Of the seven fabrics tested, five were conventional home-use fabrics and the other two were surfaces modified with hydrophobic organosilanes. Wettability and droplet adherence tests were performed on each material. The materials that performed the best were decyltrichlorosilane (DTS) modified cotton, perfluorotrichlorosilane (FTS) modified cotton, and polyester. Contact angles for water droplets on these fabrics were 106°, 93°, and …

Continuous Preparation And Application Of Novel Heterogeneous Catalysis, Michael B. Burkholder

Theses and Dissertations

Transition metal heterogeneous catalysts are widely used across many chemical industries to reduce waste and emissions and reduce production time while increasing rate. The prevalence of these materials results from the complex relationship between metal nanoparticles and supports affecting final catalytic performance. Rational catalyst synthesis describes the ability to precisely engineer structures through controlled preparation. Novel materials and continuous processing represent a promising approach for rational catalyst synthesis.

The application of these catalysts in continuous, multiphase processes, such as cross-coupling reactions, oxidation chemistry, and nitroreduction processes, are paramount to developing new commercial routes for high-value products. Pd/G catalysts synthesized by …

Scaling Film Cooling Adiabatic Effectiveness With Mass Transfer And Thermal Experimental Techniques, Luke J. Mcnamara

Theses and Dissertations

With increasing engine temperatures, it is becoming more important to design effective film cooling schemes. Low temperature, large scale tests are often implemented in the design process to reduce cost and complexity. A nondimensional adiabatic effectiveness can be used as an indication of the performance of a film cooling scheme. However, the coolant flow rate must be properly scaled between the low temperature tests and engine temperatures to accurately predict film cooling effectiveness. This process is complicated by gas property variation with temperature. Tests are commonly conducted using thermal measurement techniques with infrared thermography (IR), but the use of pressure …

Form Stable Phase-Change Materials, Russell Dent, Marjan Kashfipour, Nitin Mehra, Jiahua Zhu

Williams Honors College, Honors Research Projects

This work investigates the use of two different polyols, xylitol (Xyl) and erythritol (Ery), in conjunction with boron nitride (BN) aerogels, for the purpose of creating thermally conductive composites. While the BN filler in Xyl composites achieved a high anisotropic thermal conductivity of up to 4.53 W/m-K at 18.2 weight percent filler loading, they do not exhibit good phase-change material qualities due to a low solidification enthalpy even at low cooling rates. Alternatively, the BN-Ery composites have shown promising results with a solidification enthalpy of 225.14 J/g and a melting enthalpy of 385.84 J/g at a heat rate of 5 …

Thermophotovoltaic Devices: Combustion Chamber Optimization And Modelling To Maximize Fuel Efficiency, Arnold Chris Toppo, Ernesto Marinero, Zhaxylyk Kudyshev

The Summer Undergraduate Research Fellowship (SURF) Symposium

Currently, 110 billion cubic meters of natural gas (primarily methane), a potent greenhouse gas, are flared off for environmental and safety reasons. This process results in enough fuel to provide the combined natural gas consumption of Germany and France. The research team developed a thermophotovoltaic device to convert thermal energy to electricity at a high efficiency using proprietary emitters and combustion system. With the current focus being fuel efficiency and the combustion process, the assembly was simulated using ANSYS Fluent modelling software and the following parameters were optimized: air/fuel ratios, flow rates, and inlet sizes. Simultaneously the heat transfer across …

Bioluminescent Magnetic Nanoparticles As Potential Imaging Agents For Mammalian Spermatozoa, Erick Salvador Vasquez, Jean M. Feugang, Scott T. Willard, Peter L. Ryan, Keisha B. Walters

Chemical and Materials Engineering Faculty Publications

Background: Nanoparticles have emerged as key materials for developing applications in nanomedicine, nanobiotechnology, bioimaging and theranostics. Existing bioimaging technologies include bioluminescent resonance energy transfer-conjugated quantum dots (BRET-QDs). Despite the current use of BRET-QDs for bioimaging, there are strong concerns about QD nanocomposites containing cadmium which exhibits potential cellular toxicity.

Results: In this study, bioluminescent composites comprised of magnetic nanoparticles and firefly luciferase (Photinus pyralis) are examined as potential light-emitting agents for imaging, detection, and tracking mammalian spermatozoa. Characterization was carried out using infrared spectroscopy, TEM and cryo-TEM imaging, and ζ-potential measurements to demonstrate the successful preparation of these nanocomposites. Binding …

Growth And Properties Of Carbon Microcoils And Nanocoils, Muneaki Hikita, Robyn Bradford, Khalid Lafdi

Chemical and Materials Engineering Faculty Publications

Various types of coiled carbon filaments have been synthesized using chemical vapor deposition and other methods. These carbon filaments exhibit unique electrical and mechanical properties due to their versatile shapes and structures. To form coiled shapes, different types of catalyst compositions and reactive gases have been explored. Generally, coiled carbon filaments are classified by coil diameter and shape (e.g., microcoil and nanocoil). In this review, coiled carbon filaments are classified into three growth mechanism categories:

(1) bidirectional double helical growth;

(2) bidirectional twisted growth; and

(3) tip single helical or twisted growth.

Next, their synthesis methods and hypothetical growth mechanisms …

Slow Release Of Ions From Internalized Silver Nanoparticles Modifies The Epidermal Growth Factor Signaling Response, Kristen K. Comfort, Elizabeth I. Maurer, Saber M. Hussain

Chemical and Materials Engineering Faculty Publications

Due to their distinctive physiochemical properties, including a robust antibacterial activity and plasmonic capability, hundreds of consumer and medical products contain colloidal silver nanoparticles (AgNPs). However, even at sub-toxic dosages, AgNPs are able to disrupt cell functionality, through a yet unknown mechanism. Moreover, internalized AgNPs have the potential to prolong this disruption, even after the removal of excess particles. In the present study, we evaluated the impact, mechanism of action, and continual effects of 50 nm AgNP exposure on epidermal growth factor (EGF) signal transduction within a human keratinocyte (HaCaT) cell line. After AgNP expose, EGF signaling was initially obstructed …

Less Is More: Long-Term In Vitro Exposure To Low Levels Of Silver Nanoparticles Provides New Insights For Nanomaterial Evaluation, Kristen K. Comfort, Laura K. Braydich-Stolle, Elizabeth I. Maurer, Saber M. Hussain

Chemical and Materials Engineering Faculty Publications

In view of the vast number of new nanomaterials (NMs) that require testing and the constraints associated with animal models, the majority of studies to elucidate nanotoxicological effects have occurred in vitro, with limited correlation and applicability to in vivo systems and realistic, occupational exposure scenarios.

In this study, we developed and implemented a chronic in vitromodel coupled with lower, regulatory dosages in order to provide a more realistic assessment of NM-dependent consequences and illuminate the implications of long-term NM exposure. When keratinocytes were exposed to 50 nm silver nanoparticles (Ag-NPs), we determined that chronically dosed cells operated …

The Biological Impact Of Concurrent Exposure To Metallic Nanoparticles And A Static Magnetic Field, Kristen K. Comfort, Elizabeth I. Maurer, Saber M. Hussain

Chemical and Materials Engineering Faculty Publications

The rapid advancement of technology has led to an exponential increase of both nanomaterial and magnetic field utilization in applications spanning a variety of sectors. While extensive work has focused on the impact of these two variables on biological systems independently, the existence of any synergistic effects following concurrent exposure has yet to be investigated. This study sought to ascertain the induced alterations to the stress and proliferation responses of the human adult low calcium, high temperature keratinocyte (HaCaT) cell line by the application of a static magnetic field (approximately 0.5 or 30 mT) in conjunction with either gold or …

Tannic Acid Coated Gold Nanorods Demonstrate A Distinctive Form Of Endosomal Uptake And Unique Distribution Within Cells, Emily A. Untener, Kristen K. Comfort, Elizabeth I. Maurer, Christin M. Grabinski, Donald A. Comfort, Saber M. Hussain

Chemical and Materials Engineering Faculty Publications

One of the primary challenges associated with nanoparticle-dependent biological applications is that endosomal entrapment in a physiological environment severely limits the desired targeting and functionality of the nanoconstructs. This study sought to overcome that challenge through a systematic approach of gold nanorod (GNR) functionalization: evaluating the influence of both aspect ratio and surface chemistry on targeted cellular internalization rates and preservation of particle integrity. Owing to their unique spectral properties and enhanced surface area, GNRs possess great potential for the advancement of nanobased delivery and imaging applications. However, their ability for efficient intracellular delivery while maintaining their specific physiochemical parameters …

Carbon Nanotubes Grown On Glass Fiber As A Strain Sensor For Real Time Structural Health Monitoring, Matthew Boehle, Qiong Jiang, Lingchuan Li, Alexandre Lagounov, Khalid Lafdi

Chemical and Materials Engineering Faculty Publications

In order to more effectively monitor the health of composite structures, a fuzzy fiber sensor has been developed. The fuzzy fiber is a bundle of glass fibers with carbon nanotubes or nanofibers (CNTs or CNFs) grown on the surface. The nanotube coating makes the fiber bundle conductive while the small conductive path increases sensitivity. The fuzzy fiber sensor can replace conventional metal foil strain gauges in composite applications. The electrical response of the sensor is monitored in real time to measure strain, vibration, cracking and delamination. Continuous monitoring provides instant notification of any problems. Implementation of this sensor network in …

Nitrogen And Hydrogen Plasma Treatments Of Multiwalled Carbon Nanotubes, John G. Jones, A. R. Waite, Christopher Muratore, Andrey A. Voevodin

Chemical and Materials Engineering Faculty Publications

This article investigates plasma treatment of vertically aligned multiwall carbon nanotube (CNT) films in different plasma environments for modification of surface chemistry and morphology. The surfaces of the CNTs were functionalized with a pulsed dc plasma treatment, where the power was directly applied to the nanotube film in low pressure argon/nitrogen and argon/hydrogen backgrounds. Optical emission spectroscopy was used to detect atomic and molecular excitations in the gas mixtures as well as in pure gases in the vicinity of the CNT films. In situx-ray photoelectron spectroscopy was performed on the treated samples to examine CNT surface chemistry after treatment. …

Signaling Pathways Activated By Interleukin-2 And Interluekin-4 Receptors Mediate T Lymphocyte Clonal Expansion, Kristen K. Comfort

Chemical and Materials Engineering Faculty Publications

Cells sense and respond to chemical and physical stimuli through signal transduction pathways, which mediate cell proliferation, differentiation, migration, and survival. The cytokines interleukin-2 (IL-2) and interleukin-4 (IL-4) are key regulators of the adaptive immune system, particularly influencing the clonal expansion and differentiation of T cells. At least in culture, both synergistic and antagonistic effects of IL-2 and IL-4 co-stimulation have been reported; the antagonism, when observed, is thought to arise from the utilization of a common subunit shared by IL-2 and IL-4 receptors. We have sought to characterize IL-2 and IL-4 signaling at the level of intracellular pathways activated …

Effect Of Plasma Flux Composition On The Nitriding Rate Of Stainless Steel, Christopher Muratore, Scott G. Walton, D. Leonhardt, Richard F. Fernsler, David D. Blackwell, R. A. Meger

Chemical and Materials Engineering Faculty Publications

The total ion flux and nitriding rate for stainless steel specimens exposed to a modulated electron beam generated argon-nitrogen plasma were measured as a function of distance from the electron beam axis. The total ion flux decreased linearly with distance, but the nitriding rate increased under certain conditions, contrary to other ion flux/nitriding rate comparisons published in the literature. Variation in ion flux composition with distance was explored with a mass spectrometer and energy analyzer as a possible explanation for the anomalous nitriding rate response to ion flux magnitude. A transition in ion flux composition from mostly N2 1 to …