Materials Science and Engineering Commons^™

Oxidation Behavior Of Silicon Carbide, Matrix Graphite, And Refractory Multi-Principal Element Alloy, Visharad Jalan

Doctoral Dissertations

"The present study focuses on the investigation of the oxidation behavior of silicon carbide, matrix graphite in a water vapor environment. It also examines the oxidation behavior of refractory multi-principal element alloys when exposed to air. The oxidation behavior of silicon carbide and matrix graphite were investigated in conditions pertaining to off-normal incidents in high-temperature gas-cooled nuclear reactors. Understanding this is crucial for the prediction of their performance in such accidents and ensuring that the nuclear reactor is accident tolerant. Upon exposure to water vapor, the two A3-based matrix graphite exhibited different behaviors. The A3-27 type showed oxidation in all …

Development And Testing Of Irradiation-Tolerant High-Entropy Alloys, Matthew John Luebbe

Doctoral Dissertations

"High entropy alloys (HEAs) are a novel class of alloys made of multiple principal elements in near equal proportions. They have been observed to possess an array of useful engineering properties, such as good ductility and fracture toughness, high temperature strength, oxidation and corrosion resistance and irradiation resistance. This makes them promising candidates for harsh environments, especially nuclear reactors. These properties could potentially realize advanced Gen IV nuclear reactor designs. However, most HEA compositions contain Co, which activates under irradiation, generating safety and waste management concerns. This work studies three compositions of Co-free HEAs whose strength and microstructures are evaluated …

Ceramic Dielectrics For High Temperature Capacitor Applications, Alan Daniel Devoe

Doctoral Dissertations

Technical progress in microelectronics is allowing operation in environments that were previously considered impossible. Building complete electronic circuits for applications above 450 degrees C, such as the planned NASA missions to Venus, require a variety of active and passive components, including multilayer ceramic capacitors (MLCC).

This study explores calcium zirconate CaZrO3 and magnesium oxide MgO based dielectric compositions for MLCC applications that are capable of operating at extreme temperatures between 450 degrees C and 600 degrees C. Both materials were characterized with respect to impurities, dopants, crystal structure and microstructural development. Dielectric properties were measured to determine permittivity, dissipation factor, …

Characterization And Optimization Of Sand And Tung Oil-Based Resins For Binder-Jet 3d Printing, Daniel I. Ajiola

College of Graduate Studies: Theses & Dissertations

Binder-jet 3D printing as a transformative technology in additive manufacturing, offers the ability to fabricate complex structures with diverse materials. This thesis investigates the use of a sustainable tung oil-based resin to create composites, exploring the potential for an eco-friendly alternative to synthetic binders.

The aim of this research is to develop and characterize a bio-based resin formulation, using tung oil as the primary binder, for application in binder-jet 3D printing with sand as the reinforcement. The resin formulation was prepared by combining tung oil, n-butyl methacrylate, divinylbenzene, and di-tert-butyl peroxide in precise proportions, ensuring a balanced mixture that supports …

Effect Of Metal Ions On The Reactive Oxygen Species Scavenging Capabilities Of Cerium Oxide For Biological Applications, Agastya Mittal

Honors Undergraduate Theses

Ceria nanoparticles' capabilities to defend cells against oxidative stress through superoxide dismutase activity are well-documented. Ceria nanoparticles demonstrate a ratio between 3⁺/4⁺ oxidative states on the surface of the particles to exhibit oxygen vacancies, a feature that allows these particles to scavenge Reactive Oxygen Species (ROS) in times of Oxidative Stress. Oxidative stress arises from many wounds in the body, such as wounds in the skin, and can have significant impacts on the health of an individual. Even when receiving treatment for the skin wound, ROS can circulate from around the wound, be generated from an imbalance …

A Signal Processing And Mechanical Design Approach To Understanding Triboelectric And Piezoelectric Nanogenerators’ Output, Nicholas Rose

Honors Undergraduate Theses

Scalable energy harvesters—capable of converting motion into electrical output—provide promising solutions to increasing energy demands. This thesis was inspired by the potential biomedical applications of piezoelectric nanogenerators (PENG) and triboelectric nanogenerators (TENG). In theory, these devices could convert mechanical energy from the body into usable electricity for self-powered electronics such as pacemakers or cochlear implants. In line with this goal, this project worked to design a sustainable and biocompatible PENG; however, early devices produced inconsistent voltage. These output inconsistencies motivated an exploration of device reproducibility, but characterizing piezoelectric output signals is a particular challenge in the field. Subtle to significant …

Effect Of Aging Duration On The Microstructure And Corrosion Characteristics Of 17-4 Ph Stainless Steel, G. Narasinga Rao, Subrat Kumar Baral, Y. Madhavi, Sriram Vijayan, Ravikumar Dumpala

Michigan Tech Publications

Heat treatment plays a critical role in inducing key microstructural changes necessary to enhance corrosion resistance of 17-4 PH stainless steel (SS). During the process, precipitates form within the metal matrix, contributing to the strength of the martensitic steel. Inconsistencies in the literature concerning the response of 17-4PH SS to heat treatment have been noted. Therefore, this study examines the impact of aging duration on microstructural characteristics, microhardness, and corrosion resistance of material. The solution heat-treatment process consisted of heating the material to 1040 °C for one hour and rapid cooling in water. Subsequently, aging treatment was carried out at …

Multifunctional Nanoscale Pigments: Emerging Risks And Circular Strategies For A Sustainable Future, Ajay Vikram Singh, Preeti Bhardwaj, Vimal Kishore, Sunil Choudhary, Akihiko Hirose, Neha Gupta, Madleen Busse, Swarn Lata Singh, Christopher J. Osgood

Biological Sciences Faculty Publications

The substantial penetration of nanoscale pigments into a range of sectors has changed the dynamics of industries such as medical, material science, and many more. Nonetheless, their persistence in the environment and probable adverse impacts on health require that an assessment of such risks be formulated considering the One Health perspective. This viewpoint considers the crossing of boundaries of progress in the nanotechnology of nanoscale pigments with environmental, animal, and human health and emphasizes the significance of collaborative activity. Traditional perspectives explain the distribution of pigment history, while the nanotechnology of today's accessibility poses problems regarding utilization, toxicities, and interactions …

Investigating The Roles Of Intrinsic Point Defects And Transition Metal Doping In Monolayer And Bulk Tis2, Patrick J. Keeney

UNF Graduate Theses and Dissertations

Within this thesis, the magnetic and electronic properties of various 1T-TiS₂ systems are thoroughly examined using density functional theory (DFT) and scanning tunneling microscopy (STM). Formation energies and electronic implications of intrinsic point defects in bulk TiS₂ and monolayer TiS₂ are analyzed by approximating a computational monolayer of TiS₂ as the surface layer of a bulk sample. This approximation is validated given that intralayer covalent bonding dominates interlayer van der Waals interactions. We conclude that the most energetically favorable intrinsic defects are Ti atoms settling above the outermost S plane and S vacancies. In addition, the …

Frustrated Quantum Magnetism: The Interplay Of Isotropic And Anisotropic Interactions With Application To Α-Rucl3, Evan M. Wilson

UNF Graduate Theses and Dissertations

We investigate how anisotropic spin interactions, including Dzyaloshinskii–Moriya and Kitaev terms, manifest across quantum spin systems ranging from a single S = 1/2 dimer to molecular spin clusters and layered magnetic materials. Beginning with an exact analysis of the spin dimer, we demonstrate how singlet–triplet mixing induced by Dzyaloshinskii–Moriya interaction directly influences both thermodynamic observables and inelastic neutron scattering spectra. These microscopic fingerprints are then extended to trimer, tetramer, and tetrahedron geometries, where field-induced phase transitions and heat capacity anomalies reveal the interplay between isotropic Heisenberg and anisotropic Kitaev exchanges. In the frustrated zigzag honeycomb lattice, we show that a …

Dielectric Performance Of Fused Filament Fabricated Ultem 9085 For Naval Radome Application, Carson Rogers

UNF Graduate Theses and Dissertations

ULTEM 9085 is a high-performance thermoplastic used in the fused filament fabrication (FFF) additive manufacturing process. It has found use in applications where mechanical strength, chemical integrity, and thermal stability are of paramount importance. In this thesis, the effects of process parameters, annealing, and weathering on the mechanical and dielectric properties of FFF ULTEM 9085 have been investigated.

The first part reviews existing research on how printing parameters such as nozzle temperature, chamber temperature, print speed, infill, and layer height affect the mechanical performance of FFF ULTEM 9085. Data from the manufacturer of commonly used ULTEM 9085 filament, Stratasys, has …