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Digital Innovation Roadmap For Construction Industry: Bridging The Gap For Future, Nisa Zahin Jan 2024

Digital Innovation Roadmap For Construction Industry: Bridging The Gap For Future, Nisa Zahin

Theses and Dissertations--Civil Engineering

Digitalization has considerable value in the digital transformation of the construction business. It means the use of digital technologies to create revenue, improve business, increase profit and sustainability, and create an environment for digital business whereby digital information is at the core. As such, digital transformation requires skills that involve extracting and exchanging data and analyzing and converting that data into actionable information. In addition to technological solutions, a paramount need is to ensure that the people using these solutions and the processes used to integrate, coordinate between teams, and continuously improve the use of technology are in place. Therefore, …


The Characterization And Nanomechanical Properties Of Microstructurally Complex Systems, Kerry Ann Baker Jan 2024

The Characterization And Nanomechanical Properties Of Microstructurally Complex Systems, Kerry Ann Baker

Theses and Dissertations--Chemical and Materials Engineering

Since the dawn of civilization, the use of metals has played an integral role in the evolution of human society. Over the years, and with the introduction of new engineering and science, we have learned how to combine metals to create new metallic systems. We have expanded our understanding of dealloying and chemical reactions, and, in doing so, we created nanoporous metals. Our use of metals has evolved from basic alloys such as bronze and steel to more complex alloys such as multi-principal element alloys. Nanoporous gold is an advanced metallic system that can be created through the dealloying process. …


Advancing Combinatorial Screening Of Refractory High Entropy Alloys Through Intrinsic Ductility Assessment Via Thin Film Fragmentation Testing, Taohid Bin Nur Tuhser Jan 2024

Advancing Combinatorial Screening Of Refractory High Entropy Alloys Through Intrinsic Ductility Assessment Via Thin Film Fragmentation Testing, Taohid Bin Nur Tuhser

Theses and Dissertations--Chemical and Materials Engineering

High Entropy Alloys (HEAs), also known as Multiprincipal Element Alloys (MPEAs), represent a paradigm shift in alloy design. Unlike traditional practices that limit compositions to the edges of phase diagrams, HEAs exploit equiatomic mixing of five or more elements at the center of phase diagrams to maximize configurational entropy. This unconventional approach exponentially expands the spectrum of potential alloy compositions, rendering conventional experimental methods inadequate for exploring this extensive compositional space.

In response to these challenges, the scientific community has shown a growing interest in high-throughput techniques, encompassing both computational and experimental domains. Particularly, Refractory High Entropy Alloys (RHEAs) have …


Microstructural Investigation Of The Influence Of Geometry On The Mechanical Reliability Of Additively Manufactured Metals, Tracy Connor Varney Jan 2024

Microstructural Investigation Of The Influence Of Geometry On The Mechanical Reliability Of Additively Manufactured Metals, Tracy Connor Varney

Theses and Dissertations--Chemical and Materials Engineering

The adoption of additive manufacturing across a wide range of fields is ever-increasing, allowing for solutions that were previously impossible to achieve. This dissertation demonstrates the wide range of macro- and micro- characterization techniques used to investigate several precipitation strengthened AM alloy systems. While AM allows for nearly unlimited design freedom, this brings along its own issues as the interplay between scan strategy and part geometry is less well known. In this work, a novel thin-wall dogbone geometry was utilized to study one type of complex geometry observed in a large portion of AM focused designs. The mechanical behavior of …


Language Models For Rare Disease Information Extraction: Empirical Insights And Model Comparisons, Shashank Gupta Jan 2024

Language Models For Rare Disease Information Extraction: Empirical Insights And Model Comparisons, Shashank Gupta

Theses and Dissertations--Computer Science

End-to-end relation extraction (E2ERE) is a crucial task in natural language processing (NLP) that involves identifying and classifying semantic relationships between entities in text. This thesis compares three paradigms for end-to-end relation extraction (E2ERE) in biomedicine, focusing on rare diseases with discontinuous and nested entities. We evaluate Named Entity Recognition (NER) to Relation Extraction (RE) pipelines, sequence-to-sequence models, and generative pre-trained transformer (GPT) models using the RareDis information extraction dataset. Our findings indicate that pipeline models are the most effective, followed closely by sequence-to-sequence models. GPT models, despite having eight times as many parameters, perform worse than sequence-to-sequence models and …


Optoelectrical Properties And Photostability Of Cspbbr3 Quantum Dots: Effects Of Dopants And Ligands, Md Shad Bin Salam Jan 2024

Optoelectrical Properties And Photostability Of Cspbbr3 Quantum Dots: Effects Of Dopants And Ligands, Md Shad Bin Salam

Theses and Dissertations--Chemical and Materials Engineering

Metal halide perovskite QDs have a great potential for displays and lighting because of their exceptional optoelectronic characteristics associated with quantum confinement effect. However, the stability in the environment during the applications of halide perovskite QDs remains a significant challenge, impeding their practicality and lowering their commercial scalability. High-temperature methods are well-established for producing doped perovskite QDs, the influence of room-temperature synthesis on thermal, size-dependent optical properties, and long-term stability remains inadequately understood. Also, there is a demand for strategies to increase the absorption of light, reduce trap states, and modify the energy levels of perovskite QDs.

In this study, …


Recent Paleolimnological History Of Jackson Lake, Grand Teton National Park, Wyoming (Usa), Hillary Johnson Jan 2024

Recent Paleolimnological History Of Jackson Lake, Grand Teton National Park, Wyoming (Usa), Hillary Johnson

Theses and Dissertations--Earth and Environmental Sciences

This study utilizes a recently acquired, high-resolution CHIRP seismic reflection dataset and a deepwater sediment core to analyze the recent stratigraphy of Jackson Lake (Wyoming, USA). The western shoreline of Jackson Lake is situated adjacent to the Teton fault, a down-to-the-east normal fault that produces the spectacular high topography of Grand Teton National Park. The sediments of Jackson Lake are underexplored and consequently, their value as indicators of hydroclimatic and tectonic changes is unknown. Here, the sedimentary fill of Jackson Lake is explored as a natural archive of environmental change, specifically in reference to the influence of human outlet engineering …


Microstructural, Mineralogical, And Chemical Characterization Of The Handys Bend And Flax Creek Meteorites, Kentucky: Relevance For The Iron Meteorite Record, Ethan S.L. Davis Jan 2024

Microstructural, Mineralogical, And Chemical Characterization Of The Handys Bend And Flax Creek Meteorites, Kentucky: Relevance For The Iron Meteorite Record, Ethan S.L. Davis

Theses and Dissertations--Earth and Environmental Sciences

Iron meteorites remain the only material view into planetary cores. Despite their scientific relevance, iron meteorites are relatively rare. In June 2021 and March 2022, the Kentucky Geological Survey received requests to identify two metallic specimens discovered in central Kentucky. The specimens were given the provisional names Handys Bend (3175.2 g) and Flax Creek (286.2 g). The goal of this project is to confirm meteoritic origin, characterize their structures and chemistry, assign genetic classifications, and examine potential relations to previous discoveries. Petrography was conducted using scanning electron microscopy. Mineral phases were examined using X-Ray diffraction crystallography. Chemical compositions were determined …


Thermal Alteration Of The Mineralogy Of Calcium Sulfoaluminate Cements: Implications For The Performance Of Rapid Repair Materials, Jillian Cavellier Jan 2024

Thermal Alteration Of The Mineralogy Of Calcium Sulfoaluminate Cements: Implications For The Performance Of Rapid Repair Materials, Jillian Cavellier

Theses and Dissertations--Earth and Environmental Sciences

Calcium sulfoaluminate (CSA) was developed in part to lessen the environmental impact of cementitious materials compared to traditional Portland cements. CSA was first put into production in the 1970s and has been undergoing various performance testing to investigate its durability. Yet to be evaluated is CSA’s response to a rapid, high temperature event. In this study, X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectrometry and scanning electron microscope imaging were used to analyze alterations in the mineralogy due to such an event. As found in previous studies, after ~125°C, ettringite has been completely dehydrated. Ettringite decomposes into bassanite and calcium …


Visualizing And Automating Past, Real-Time, And Forecast Dynamic Hazard Maps For Shallow Colluvial Landslides In Eastern Kentucky, Nathaniel O'Leary Jan 2024

Visualizing And Automating Past, Real-Time, And Forecast Dynamic Hazard Maps For Shallow Colluvial Landslides In Eastern Kentucky, Nathaniel O'Leary

Theses and Dissertations--Earth and Environmental Sciences

Landslide hazards are a persistent threat to communities and infrastructure in Eastern Kentucky, where steep slopes, shallow colluvial soils, and variable hydrological conditions make slope failures frequent. This thesis presents an integrated approach to landslide hazard mapping (LHM) through the development of dynamic, spatiotemporal LHMs for shallow colluvial landslides. Two studies within this work investigate and refine the use of the Lu and Godt (2008) factor of safety (FS) equation to improve landslide predictions. The first study establishes a novel LHM workflow using Hydrus-1D to simulate soil moisture infiltration and fluctuations from precipitation and evapotranspiration (ET) data. This study also …


Sh-Wave Seismic-Reflection Efficiency Technique For Investigating The Wolf Island Fault, New Madrid Seismic Zone, Usa, Stephanie Vicroy Jan 2024

Sh-Wave Seismic-Reflection Efficiency Technique For Investigating The Wolf Island Fault, New Madrid Seismic Zone, Usa, Stephanie Vicroy

Theses and Dissertations--Earth and Environmental Sciences

The Reelfoot Fault within the New Madrid seismic zone has displacement at seismogenic depth to which the surface expression has unequal displacement. Previous work identified northeast-oriented transpressional fault strands northeast of a bend in the scarp as evidence for a through-going shear-zone, acting as potential accommodation for the observed strain imbalance. This investigation projected the trend of these faults to their intersection with an industry seismic survey at Wolf Island, Missouri, which exhibits a similarly structured faulted zone. We suggest this structure is the continuation of the through-going shear zone representing a previously unknown 22-km-long Quaternary-active fault that can affect …


High Resolution Sedimentary Investigations Of Extant Lakes In North America, John Dilworth Jan 2024

High Resolution Sedimentary Investigations Of Extant Lakes In North America, John Dilworth

Theses and Dissertations--Earth and Environmental Sciences

Investigation of past lake environments forms the discipline of paleolimnology. Paleolimnological studies seek to evaluate geophysical, geochemical, and ecological proxies and indicators contained within lake sediment archives. Using these potential stores of high-resolution environmental information, questions regarding climate, biological, and geochemical changes experienced by a lake and its watershed can be investigated. This dissertation research utilized lake sediment records from two lakes within North America to study different aspects of environmental change. This dissertation consists of three separate studies presented in three chapters.

Chapter Two presents a retrospective environmental assessment of Jackson Lake, Wyoming to investigate the impacts of dam …


A Geography Of Transgender Belonging In Louisville, Kentucky, Lj Mcallister Jan 2024

A Geography Of Transgender Belonging In Louisville, Kentucky, Lj Mcallister

Theses and Dissertations--Geography

Louisville, Kentucky is home to a surprisingly robust – and complex – transgender community. This study uses qualitative data from interviews, collaborative maps, and archival research to analyze a geography of belonging for transgender residents in the city. It discusses how the twelve participants negotiate their relationships with the conservative, “red” state of Kentucky, as well as the geographical decision-making they use to navigate Louisville’s many neighborhoods. Ultimately, this thesis draws attention to the ways in which prejudice shapes the landscape of belonging for transgender life in Derby City.


Advanced Mathematical Graph-Based Machine Learning And Deep Learning Models For Drug Design, Farjana Tasnim Mukta Jan 2024

Advanced Mathematical Graph-Based Machine Learning And Deep Learning Models For Drug Design, Farjana Tasnim Mukta

Theses and Dissertations--Mathematics

Drug discovery is a highly complicated and time-consuming process. One of the main challenges in drug development is predicting whether a drug-like molecule will interact with a specific target protein. This prediction accelerates target validation and drug development. Recent research in biomolecular sciences has shown significant interest in algebraic graph-based models for representing molecular complexes and predicting drug-target binding affinity. In this thesis, we present algebraic graph-based molecular representations to create data-driven scoring functions (SF) using extended atom types to capture wide-range interactions between targets and drug candidates. Our model employs multiscale weighted colored subgraphs for the protein-ligand complex, colored …


Advancements In Elliptic Mesh Redistribution And Automated Overset Grid Generation For Computational Fluid Dynamics, Chase Ashby Jan 2024

Advancements In Elliptic Mesh Redistribution And Automated Overset Grid Generation For Computational Fluid Dynamics, Chase Ashby

Theses and Dissertations--Mathematics

Automated and robust structured curvilinear overset grid generation remains a significant challenge for the application of computational fluid dynamics. This thesis intro- duces a specialized anisotropic Mach cone aligned adaptation algorithm for low-boom simulations and an automated procedure for generating structured curvilinear overset grids for immersed boundary simulations. Results demonstrate that anisotropic mesh adaptation can reduce computational resource usage by over 50% while maintaining sonic boom prediction accuracy across the entire sonic boom domain compared to user-constructed Mach cone aligned grids. The proposed immersed overset grid gen- eration procedure eliminates the need for complex surface generation algorithms, producing grids suitable …


Modulating The Mtor Pathway Using Inducible Retrogradely Transported Aavs As A Novel Approach To Improve Motor Recovery In Spinal Cord Injury, Christopher Bosse-Joseph Jan 2024

Modulating The Mtor Pathway Using Inducible Retrogradely Transported Aavs As A Novel Approach To Improve Motor Recovery In Spinal Cord Injury, Christopher Bosse-Joseph

Theses and Dissertations--Medical Sciences

Spinal cord injury poses multiple regeneration barriers, including neuronal-intrinsic and extrinsic factors. Overcoming these barriers has stood as a longstanding challenge in neuroscience. A well-studied mechanism to promote spinal cord regeneration and locomotor recovery is activating the PI3K/mTOR pathway by knocking out phosphatase and tensin homolog protein (PTEN). PTEN knockout (PTEN-KO) studies have traditionally used adeno-associated virus (AAV) viral vectors to improve functional recovery. The use of traditional AAV serotypes to induce PTEN-KO has shown promise to improve functional recovery in rodent models; however, these approaches show significant limitations for translational utility. Firstly, the use of traditional AAV serotypes to …


The Role Of Intracellular Growth During The Systemic Spread Of Listeria Monocytogenes, Jamila S. Tucker Jan 2024

The Role Of Intracellular Growth During The Systemic Spread Of Listeria Monocytogenes, Jamila S. Tucker

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Listeria monocytogenes is a facultative intracellular pathogen transmitted through the consumption of contaminated food products. Typically, infections range from mild, self-limiting gastroenteritis to life-threatening systemic infections; however, the events that occur in the gut to allow for this spread are unclear.

The focus of my thesis aims to determine how L. monocytogenes escape the mesenteric lymph nodes (MLN), the final barrier to systemic spread for both commensal and pathogenic bacteria in the gut. I have shown that intracellular replication of L. monocytogenes in an as-yet-unidentified cell type is essential for the colonization and dissemination of the bacteria from the MLN. …


The Effect Of Estrogen And A Mitochondrial Uncoupling Prodrug On Traumatic Brain Injury-Induced Dysfunction In Mice., Olivia J. Kalimon Jan 2024

The Effect Of Estrogen And A Mitochondrial Uncoupling Prodrug On Traumatic Brain Injury-Induced Dysfunction In Mice., Olivia J. Kalimon

Theses and Dissertations--Neuroscience

A large percent of both clinical and pre-clinical traumatic brain injury (TBI) studies report better outcomes females after severe injury compared to males. Mitochondrial dysfunction is a well-characterized driver of secondary injury and an attractive neurotherapeutic target; though, there is limited research available on mitochondrial dysfunction in females. However, a few studies have shown total mitochondria from the cortex of females appear protected from TBI-induced bioenergetic dysfunction. These results were replicated in these studies so further characterization was performed. Additionally, protein expression of some oxidative phosphorylation (OXPHOS) complexes were elevated in the uninjured cortex of females relative to uninjured males, …


Relationality In Rousseau's Philosophy Of Education, Thayne Cameron Jan 2024

Relationality In Rousseau's Philosophy Of Education, Thayne Cameron

Theses and Dissertations--Philosophy

Jean-Jacques Rousseau’s assertion of Emile that “Our true study is that of the human condition” serves as the foundation for this dissertation, which examines the significance of certain kinds of basic experiential relationships in Rousseau’s philosophy of education. By analyzing the relationships between the self and objects, the self and others, and the educator and the learner, this work elucidates how these interactions underpin Rousseau’s pedagogical views and their implications for fostering personal and social virtue.

The dissertation explores the self-object relationship through affectivity, embodiment, and purposeful activity, demonstrating how direct engagement with objects shapes perceptions and behaviors. It then …


The Methodology For Integrating Robotic Systems In Undeground Mining Machines, Peter Kolapo Jan 2024

The Methodology For Integrating Robotic Systems In Undeground Mining Machines, Peter Kolapo

Theses and Dissertations--Mining Engineering

Roof bolting is a critical operation in ensuring the safety and stability of underground mines by securing the roof strata with bolts. The process involves moving and manipulating heavy tools while being vigilant about the safety of the area. During the installation of roof bolts, operators are exposed to hazardous conditions due to challenging working conditions in underground mines, extensive working hours, and demanding shift schedules leading to personnel fatigue and influencing operators to take shortcuts that may increase the risk of injuries and fatal accidents. The successful completion of roof bolting tasks depends heavily on operator judgment and experience …


Autonomous Shuttle Car Docking To A Continuous Miner Using Rgb-Depth Imagery, Sky Rose Jan 2024

Autonomous Shuttle Car Docking To A Continuous Miner Using Rgb-Depth Imagery, Sky Rose

Theses and Dissertations--Mining Engineering

A great deal of research is currently being conducted in automating mining equipment to improve worker health and safety and increase mine productivity. Significant progress has been made in some applications, e.g., autonomous haul trucks for surface mining. However, little progress has been made in autonomous face haulage in underground room-and pillar coal mines. Accordingly, this thesis addresses automating the operation of a shuttle car, focusing on positioning the shuttle car under the continuous miner coal-discharge conveyor during cutting and loading operations. The approach uses a stereo depth camera as the sensor, and machine-learning algorithms are used to identify various …


Discrete Element Modeling To Predict Muckpile Profiles From Cast Blasting, Russell Lamont Jan 2024

Discrete Element Modeling To Predict Muckpile Profiles From Cast Blasting, Russell Lamont

Theses and Dissertations--Mining Engineering

Movement of overburden or ore from one location to another may be considered the primary physical process of mining. The means by which it is transported is then of primary concern both to economic production and cost control. The geologic characteristics of some mineral deposits, especially coal and phosphates, lend themselves to overburden transport by means of cast blasting, which when efficiently designed has proven itself to be a cheaper method than traditional truck/shovel, dragline, or even dozer push transport. Simultaneously, this movement of a significant portion of overburden using explosives may enable an operation to increase mineral production, as …


Prediction Of Final Subsidence Under Dipping Seam Conditions, Ernesto Maldonado Esguerra Jan 2024

Prediction Of Final Subsidence Under Dipping Seam Conditions, Ernesto Maldonado Esguerra

Theses and Dissertations--Mining Engineering

The prediction of ground movements due to underground coal mining and their impacts on the surface are essential considerations that numerous researchers worldwide have studied. Most of these studies have focused on developing different analytical and empirical models for predicting and calculating ground deformation indices for flat or gently dipping seams under variable topography. However, a few studies are available on predicting ground movements under dipping seam conditions. Although most inclined coal seams are in China, India, and a few other countries, dipping seam conditions have been encountered in some cases in the US, where the inclination (dip) may be …


Copper Ammoniacal Recycling Process Development For Leaching Electrolyte, Solvent Extraction, And Electrowinning, Zulqarnain Ahmad Ali Jan 2024

Copper Ammoniacal Recycling Process Development For Leaching Electrolyte, Solvent Extraction, And Electrowinning, Zulqarnain Ahmad Ali

Theses and Dissertations--Mining Engineering

Electronic waste (e-waste) encompasses waste originating from electronic and electrical equipment. In 2022, 59.4 million metric tons of e-waste were generated, projected to increase to 74.7 million metric tons by 2030. Among the most valuable components within E-Waste are the printed circuit boards (PCBs), primarily composed of metals including copper (Cu), gold (Au), silver (Ag), cobalt (Co), nickel (Ni), bismuth (Bi), and various other base and precious metals. Notably, copper is the predominant element in PCBs, with concentrations exceeding those in their respective ores. The high demand for copper driven by the ongoing push towards greener technologies and its abundant …


Characterization And Concentration Of Critical Minerals And Rare Earth Elements From Primary And Secondary Silicate Deposits, Muhammed Melih Elseyh Jan 2024

Characterization And Concentration Of Critical Minerals And Rare Earth Elements From Primary And Secondary Silicate Deposits, Muhammed Melih Elseyh

Theses and Dissertations--Mining Engineering

Critical materials (CMs) are crucial for sustainable energy. This investigation explored the extraction of rare earth elements (REEs) from the Halleck Creek deposit in Wyoming, and CMs from a construction sand deposit in Missouri. The Halleck Creek deposit is REE enriched (0.32%) as the mineral allanite within silicious host rock. Density fractionation tests revealed that 70% of the gangue can be rejected while recovering 90% of the REEs with an upgrading ratio of 4.5:1. By exploiting allanite’s paramagnetic properties, magnetic separations achieved a TREE upgrade ratio of 3:1 with 87% TREE recovery. Based on the density fractionation results, a rougher-scavenger-cleaner …


The Determination Of Darcy Permeabilities And Slip Parameters In Porous Thermal Protection Media Via Pressure-Driven Steady Flows At Varying Levels Of Thermal Decomposition, John Ryan O'Nan Jan 2024

The Determination Of Darcy Permeabilities And Slip Parameters In Porous Thermal Protection Media Via Pressure-Driven Steady Flows At Varying Levels Of Thermal Decomposition, John Ryan O'Nan

Theses and Dissertations--Mechanical and Aerospace Engineering

A flow apparatus for determining the Darcy permeability and Klinkenberg molecular slip adjustment parameter in arbitrary porous media was created. Two leak-proof methods were developed to secure samples of porous media in the flow apparatus independent of surface irregularities, structural integrity, or material porosity. The first of these methods uses thermoset resin casting to permit material samples of a highly irregular profile to be studied. The second method utilizes heat-shrink polyolefin tubing to create a wall seal while preserving the exposed faces of a given cylindrical sample, enabling the study of inhomogeneous surface features. These methods were used to characterize …


Transfer Learning-Enhanced Transformer For Virtual Sensing Applications In Resistance Spot Welding, Ethan York Jan 2024

Transfer Learning-Enhanced Transformer For Virtual Sensing Applications In Resistance Spot Welding, Ethan York

Theses and Dissertations--Mechanical and Aerospace Engineering

Resistance spot welding is a crucial manufacturing process used across a wide range of industries for permanently joining metal components. Characterized by its applications in the automotive industry, resistance spot welding is valued for its speed, efficiency, and relatively low cost to set up and maintain. The process involves running a pulse of electrical current through two metal sheets to liquify the material and create a permanent bond. The process complexity necessitates precise control over various parameters to ensure acceptable results, emphasizing the importance of quality control. Because there are no low-cost and non-invasive techniques to inspect welds, strategies utilizing …


Propagation Of Vibro-Acoustic Energy In Ducts: Measurement, Simulation, And Attenuation Studies, Caoyang Li Jan 2024

Propagation Of Vibro-Acoustic Energy In Ducts: Measurement, Simulation, And Attenuation Studies, Caoyang Li

Theses and Dissertations--Mechanical and Aerospace Engineering

Vibro-acoustic energy propagates through heating, ventilating, and air conditioning (HVAC) systems through both airborne and structureborne paths. In this research, measurement and simulation studies are performed to better understand this propagation of energy and how to better attenuate the sound before it impacts building occupants.

First, a scaled-down experiment was developed to assist in the validation of numerical simulation models. A small source room was attached to a wooden duct with variable cross-sectional area. The sound power for both untreated and treated ductwork was measured using sound intensity scanning, and the insertion loss is the difference between untreated and treated …


Artificial Intelligence Enabled Machinery Fault Detection And Diagnosis Using Vibro-Acoustic Signals, Srinivasa Rao Ippili Jan 2024

Artificial Intelligence Enabled Machinery Fault Detection And Diagnosis Using Vibro-Acoustic Signals, Srinivasa Rao Ippili

Theses and Dissertations--Mechanical and Aerospace Engineering

In various industries, the early detection of faults in rotating machinery is crucial to prevent system failures and ensure customer satisfaction. Typically, vibration measurement and diagnosis are employed for fault detection, but this process faces challenges in automation due to the complexity of installing and maintaining accelerometers, particularly in end-of-line quality control or pre-installed machinery health assessments. Acoustic signals, as a form of mechanical wave, offer an alternative for monitoring machinery while in operation. Unlike accelerometers, acoustic transducers are non-contact and easy to set up, enabling real-time data collection without interrupting equipment operation. However, utilizing acoustic signals in manufacturing poses …


Characterization Of The Spallation Phenomenon In Ablative Thermal Protection System Materials Resulting From Arc-Jet Experiments, Kristen Price Jan 2024

Characterization Of The Spallation Phenomenon In Ablative Thermal Protection System Materials Resulting From Arc-Jet Experiments, Kristen Price

Theses and Dissertations--Mechanical and Aerospace Engineering

Thermal protection systems are critical for protecting spacecraft from the large amounts of heating incurred during atmospheric entry. Ablative thermal protection systems in particular often consist of a carbon fiber matrix impregnated with a polymer resin and use thermal and chemical reactions to decompose the material. Weakening of these carbon fibers by oxidation, along with the impact of shear forces, results in the mechanical failure of these materials in a process known as spallation. Being able to quantify and characterize this process is important for modeling and designing heat shield materials that account for the additional spalled mass loss.

Two …