Digital Commons Network^™

Enabling Smart Healthcare Applications Through Visible Light Communication Networks, Jack Manhardt

Masters Theses

"Future smart healthcare operations are envisioned to require the support of high-performance wireless networks. Researchers are presented with a problem, however, as the hospital environment brings unique challenges to the application of traditional radio-frequency wireless communication networks due to health concerns and electromagnetic compatibility standards. To meet these challenges and support the advancement of high-quality healthcare, we propose the use of an alternative wireless technology in visible light communication (VLC). Contributing to the growing interest in VLC amongst researchers, we construct both a VLC network simulation testbed as well as real-world testbed to serve as a platform for the development …

Does Health Oriented Leadership And Access To On-Demand Mental Health Therapists Via Employee Assistance Programs Improve Employee Well-Being And Engagement?, Amber Rachelle Davis

Masters Theses

"Employee mental health effects are informally relevant in all facets of working adults’ lives. Considering the life-altering effects of the 2019 pandemic on work and society, mental health and work share applicability in conversations related to organizational outcomes. Based on the job demands-resource theory, personal demands are high in organizations where workers must adjust to returning to onsite work, in settings occupied by varying personalities, and ever-present political tension. These adjustments can be stressful for people and add new workplace challenges.

Work stress was found to be an antecedent for burnout (Tummers & Bakker, 2021), and leaders play an essential …

Open-Ended Hollow Coaxial Cable Resonance Sensing Via Permittivity Fluctuations For Applications To Exhaled Breath Health Monitoring, Peter Henry Holtmann

Masters Theses

"We report a pre-diagnostics breath analyzer based on the open-ended hollow coaxial cable resonator (OE-HCCR) to achieve real-time differentiation of healthy and compromised lung function through electromagnetic analysis of exhaled breath matter. A two-phase amplification scheme of electromagnetic signatures metered via the S11 phase curve offers high sensitivity to permittivity fluctuations in exposed airflow. The mathematical model of the breath analyzer is explained, followed by experimental validation of numerical findings from previous work. The collection of breath transient signals is performed through monitoring the reflected power magnitude and phase of the scattering parameter (S11) at the resonance frequency. Material fluctuations …

Fiber Assisted Re-Assembly Preformed Particle Gel For Conformance Control, Zhe Sun

Masters Theses

"In Enhanced Oil Recovery technology today, gel treatments have been implemented as a cost-effective method to improve the oil sweep efficiency in reservoirs by plugging the high permeability zones. This study presents a novel gel composition to be used in conformance control in order to improve oil recovery for mature oilfields.

The product is a fiber-assist re-assembly preformed particle gel which could be generalized to the preformed particle gels (PPG). The product developed in this study could be injected into the reservoir act as a conformance control agent by plugging water thief zones and channels in the beginning process. Due …

Investigation Of The Relationships Between Hydraulic, Physical, And Biological Soil Parameters At A Vineyard In Saint James, Missouri, Lyndsey Bennett

Masters Theses

"Soil is a living, dynamic system that performs vital functions such as crop production, organic matter decomposition, and the flow and transport of water. Given the pressures of food and in some locales water security, climate change, and sustainability, farmers, scientists, and other related specialists and stakeholders must have access to understandable soil health indicators as well as the soil hydraulic function parameters to maximize crop growth while maintaining soil health. Although biological and physical soil parameters are different, we aim to evaluate their relationship at the field scale. Hydraulic conductivity in the vadose zone may be especially important, as …

Production Of Glass-To-Metal Seals Using Additive Manufacturing Techniques, Aaron Read

Masters Theses

"Glass-to-metal (GtM) seals are hermetic barriers between glass and metal components, often used in the electronic and vacuum industries. Creating the seals traditionally requires heating all the components to the glass melting temperature, where the glass will flow and bond to the metal. Due to the manufacturing constraints of the individual components and sealing conditions there are geometric and material restrictions. Additive manufacturing techniques were used to make GtM seals to reduce these restrictions.

Hermetic, single pin seals were produced using printed metal shells, by selective laser melting (SLM), and digital light processing (DLP) printed glass preforms. Glass preforms were …

Development Of A Novel Bioink For Human Vascularized Organoids, Bradley Allen Bromet

Masters Theses

"There is a need for a model to better mimic human physiology in the clinic, so the objective was to develop a novel bioink for a 3D tissue model to study human disease and development in a dynamic 3D environment. The results from each corresponding study helped in developing a novel bioink for use in a bio printed human vascularized organoid. The bioink composed of alginate with other natural hydrogels to function as extracellular matrix and with the addition of borophosphate bioactive glasses (BPBGs) to replace growth factors, can be used with multiple cell types to bio print the proposed …

Directed Energy Deposition Processing-Performance Relationship Of Af9628, Mianqing Yang

Masters Theses

"AF9628 low alloy steel is a novel steel known for its low cost, high hardness, and outstanding tensile performance. However, the processing methods of AF9628 have been less studied in the additive manufacturing field. As the balance of hardness and tensile results is closely related to the cooling process during manufacturing process window and its relationship to resultant tensile properties is explored. By using the DED method, specimens of this steel are successfully fabricated, and tensile test results are obtained. The AF9628 steel can be manufactured for tailored properties with the DED process by controlling the cooling method. This work …

Low Finesse Extrinsic Fabry-Perot Interferometer (Efpi) Demodulation For High Temperature Gap Measurements, Abhishek Prakash Hungund

Masters Theses

"In continuous casting steel industries, mold flux is added to provide thermal and chemical insulation for molten steel. The mold flux absorbs detrimental inclusions from the steel and promotes uniform heat distribution to prevent sticking. To promote flux infiltration, mold oscillation is used, but this creates oscillation marks that reduce local shell growth and increase temperatures. Wide (2-3 mm) and deep (0.5-0.9 mm) oscillation marks with areas of 1.1-2.5 mm² are observed, affecting the steel quality, which results in a loss of 6% per billet to the industry. To address this challenge, we propose an extrinsic Fabry-Perot interferometer (EFPI) sensor …

High-Pressure Infiltration Process For Additively Manufactured Ceramic Matrix Composites, Samuel Weiler

Masters Theses

"Ceramic matrix composites were developed in order to increase the fracture toughness, thermal shock resistance, and elongation of ceramic materials, while maintaining the very high temperature capabilities of these materials. A renewed focus has been placed on ceramic matrix composites due to the need for materials that maintain good mechanical strength at very high temperatures, for use in the extreme environments encountered by hypersonic vehicles, jet turbine blades, and the like. However, conventional methods to manufacture CMCs are costly and time consuming. The aim of this work is to develop a method for creating additively manufactured ceramic matrix composites using …

Radiofrequency Interference Detection Using Lstmand Statistical Analysis Discriminator, Luke Smith

Masters Theses

"Wireless devices are becoming increasingly pervasive across all aspects of society. Examples of such devices include radios, routers, mobile phones, tablets, and more. As the number of radio frequency (RF) devices continues to rise, so does the amount of interference and noise increase. This is why an efficient approach to interference detection is explored. Most research within this area has been done strictly within the frequency domain as viewing a signal within this domain provides many insights into what makes the signal. This has, however, led to the time domain being underutilized for this area of research.

To explore the …

Laboratory Scale Experimental Analysis Of The Effect Of Surfactants On Acid Mist Suppression During Copper Electrowinning, Thurman Kollie Elgin

Masters Theses

"The reduction in acid mist generation is an industrial occupational objective in the electrowinning industry of base metals. The technology of electrowinning as an extractive metallurgical technique of metals proficiently contributed to the recovery of pure base metals. During the process of electrowinning, oxygen bubbles are generated on the anode of the electrowinning cell because of the over potential in the cell due to high voltage. The bubbles formed tend to contain sulfuric acid of the electrolyte in the form of liquid-gas ascending particles of the solution. As these bubbles ascend to the surface of the solution, they burst at …

The Geodetic Strain Rates From Gnss In The North American-Carribean-Cocos Triple Junction In Guatemala And Implications For Seismic Hazard, Tanaya Kashyap

Masters Theses

"Geodetic velocity data are pivotal for deciphering seismic risks, providing initial constraints for crustal surface strain rates. Gaining an understanding of the 2D surface strain tensor across an entire area necessitates knowledge of the surface velocity field, yet geodetic data such as measurements from the Global Navigation Satellite System (GNSS) are dispersed across the Earth’s surface. In the current scope of study, we have employed various methodologies to estimate strain rates in Guatemala, utilizing GNSS velocity data and leveraging the open-source Python tool Strain_2D. Strain_2D facilitates the computation of strain rates through diverse methods applied to the same dataset and …

Processing & Properties Of Zirconium Carbide Manufactured By Ceramic On-Demand Extrusion, Clare Sabata

Masters Theses

"This research focuses on the development of a zirconium carbide (ZrC) paste for use in material extrusion direct ink write additive manufacturing (AM) followed by the pressure less densification of ZrC and the mechanical and thermal characterization of the resulting ceramics. A highly loaded, aqueous paste was developed using commercial ZrC powder ball milled to ~1 μm. Optimal dispersant, binder, and solids loading were found by rheological characterization. The paste composition consisted of 46-47 vol% ZrC, 43.5 vol% distilled water, 8.1 vol% dispersant, and 1.6 vol% binder. A yield stress of ~8 Pa allowed for shape retention upon removal of …

Cryptographic Algorithms, Cryptocurrencies, And A Predictive Model Of Bitcoin Value By Pls Regression, Paul Kenneth O'Connor

Masters Theses

"With the invention of Bitcoin in 2009, as a seemingly timed response to the ongoing financial crisis, the popularity of the cryptocurrency has since continued to grow. Just this year, the Security Exchange Commission approved Bitcoin for exchange traded funds, allowing major investment firms to begin product trading. With this approval, and during this very moment of writing, Bitcoin has entered a bull market and reached a record value of over 72,000 USD. In addition, the Bitcoin halving event in April of 2024 is expected to increase demand even further. It has been anticipated that Bitcoin and other cryptocurrencies will …

Branching Fractional Brownian Motion, Reece Beattie-Hauser

Masters Theses

"Fractional Brownian Motion (FBM) is a Gaussian process whose increments are correlated over long times. FBM is an example of anomalous diffusion, and recently it has been used to model the distribution of serotonergic fibers in the brain [1, 2]. To better represent these fibers, branching FBM (bFBM), where FBM trajectories may randomly split into two, is introduced. One-dimensional bFBM is studied in both sub diffusive and super diffusive regimes, examining three potential behaviors of the correlations (memory) in a branching event: both trajectories retain the memory of previous steps, only one keeps the memory, and neither keeps the memory. …

Microwave Materials Characterization Of Geopolymers, Jared Sinkey

Masters Theses

"The purpose of this work was to develop a process for studying geopolymer materials using a microwave materials characterization approach. Such an approach is known to provide information about chemical and physical properties of materials. As such, in this work, the focus is on the role of water in the geopolymer curing process. To do this, specimens were prepared and cast and microwave measurements conducted throughout the curing process using a short-circuited rectangular waveguide (SC-RWG) measurement technique. In this technique, the complex reflection properties/coefficient of the sample are measured. The effect of sample length and dielectric properties on materials characterization …

The Exponential Function In Discrete Fractional Calculus Under The Delta Operator, Brayton James Link

Masters Theses

"Previously the exponential problem in discrete fractional calculus under the nabla operator was solved with the discrete Mittag--Leffler function. We now show the solution to the exponential problem in discrete fractional calculus under the delta operator, providing multiple derivations of the solution with recursion and Laplace transforms. We also share some computational and numerical results of experiments with different orders of difference to display the nature of the solution" -- Abstract, p. iii

Investigating Accident-Tolerant Cladding In A Molten Salt-Cooled Micro-Reactor Using Multi-Physics Analysis And Uncertainty Quantification, Alexander Niles Foutch

Masters Theses

"Renewed interest in nuclear safety has resulted in development of accident-tolerant materials, such as cladding. Although developed for light water reactors, their use in more advanced reactors would save time and development costs for other new materials. This paper performed a Multiphysics investigation into the power profile, thermodynamics, heat transfer, and tensor mechanics of four candidate materials (Haynes 230, Zircaloy-4, FeCrAl, and SiC-SiC), using the highly benchmarked Kilo power design as an example of a high-temperature, highly enriched, sodium-cooled microreactor environment.

From neutronic code MCNP, no significant difference in power profile was found among the four. Using finite element software …

Discrete Event Simulation (Des) In Swapping/Charging Of Battery Electric Vehicles In Underground Mining, Albert Einstein Amponsem

Masters Theses

"With climate change concerns escalating, international agreements such as the Kyoto Protocol, the US Presidential Policy, and the Paris Agreement aim to reduce greenhouse gas (GHG) emissions, targeting significant reductions by 2050. The mining sector, a notable contributor to GHG emissions primarily through diesel-powered material haulage, emits approximately 68 million tons of CO₂ annually. Transitioning to Battery Electric Trucks (BETs) presents a viable mitigation strategy by replacing diesel trucks with electric alternatives, thus eliminating CO₂ emissions.

However, the effectiveness of BETs hinges on optimized battery swapping and charging procedures. This study employs Discrete Event Simulation (DES), a computational …

Comparative Study Of Crypto Volatility And Price Forecasting Using A Mixture Of Time Series And Machine Learning Models, Abhishek Kafle

Masters Theses

"Forecasting financial product volatility and price is crucial for informed decision-making in investment and risk management. The models considered include GARCH, LSTM, GRU, BiLSTM, and hybrid models that incorporate various combinations of these models. We present a comparative analysis of forecasting volatility and price using the aforementioned models.

We also introduce a user-friendly dashboard for model training and evaluation, enabling users to upload datasets and customize model parameters. The dashboard allows users to select the type of model, specify the dataset range for training, determine the number of epochs, adjust the number of layers for deep …

Environmental Health And Impact Of Workload On Errors For Wildland Fire Personnel, Michael Bryan Held

Masters Theses

"This thesis offers an analysis of how environmental health and workload affect wildland fire dispatchers and firefighters, combining results from two studies. The first study, "Environmental Health of Wildland Firefighters: A Scoping Review," performs a scoping review of scientific literature that examines the unique environmental health challenges wildland firefighters face. The review points out the increased risks to safety, health, and well-being from more exposure to natural hazards, identifying key research gaps and priorities. It stresses the need to broaden the geographic and demographic scope of studies, improve analytical methods, and increase research funding and focus for wildland firefighters.

The …

The Graduation Walk: Pareto Optimization Of Degree Paths, Arianna Gail Sy Chaves

Masters Theses

"A student’s academic history, course availability at their institution, and the overall degree of difficulty of the schedule for each semester are all critical factors in their academic success and experience. This thesis proposes an advanced recommendation algorithm that considers these real and conflicting factors that are involved in identifying a prudent degree path - a semester-by-semester course schedule to graduation - for each student. The original contribution of this work is the use of weighted-sum multi-objective constraint programming to minimize an increased number of optimization criteria and identify Pareto-optimal degree paths to be recommended to the student. The conflicting …

Ontogenetically Driven Changes In The Endocranial Anatomy Of Maiasaura Peeblesorum And Its Implications For Sensory Functions, Emma Puetz

Masters Theses

"Hadrosaurids exhibited extreme morphological diversity and behavioral characteristics that can be compared with other, closely related members of Dinosauria – particularly through the study of neuroanatomy. X-ray CT generated endocrania of the Late Cretaceous saurolophine hadrosaur Maiasaura peeblesorum, known as the “good mother” dinosaur, offers a unique opportunity to compare complex ecological behaviors between non-avian dinosaurs and their modern archosaur relatives. The 3D reconstruction software ORS Dragonfly provided linear and volumetric measurements taken from the digital cranial endocast and endosseous labyrinths of three ontogenetically varied M. peeblesorum specimens from the Two Medicine Formation in Montana that were used to …

Learn From The Past: Using Peer Data To Improve Course Recommendations In Personalized Education, Colton Walker

Masters Theses

"This work describes a recommendation approach designed to enhance student success by identifying semester schedules and graduation paths. The primary objective is to provide personalized graduation path recommendations rooted in individual student performance and draw insights from the academic journeys of similar students who successfully graduated. The original research contribution of this work lies in the development of a graduation path recommender system that leverages a combination of Markov Decision Process, Q-Learning, and collaborative filtering techniques to pinpoint graduation paths with a higher likelihood of leading students to success based on their academic progress thus far. The effectiveness of the …

Evaluating Electromagnetic Interference On Gnss Receivers, Giorgi Tsintsadze

Masters Theses

"Due to high power and efficiency requirements of modern electrical drive system, inverters are utilizing fast-edge pulses as a drive signal. The high frequency pulses contain higher order harmonics can radiate electromagnetic interference above accepted levels. Modelling and understanding the mechanism that causes the radiation is studied, modelled and presented as gray-box model which contains circuit level modelling of coupling between electrical machine phase windings and low power sensor harness. The thesis consists of two main papers. In the first paper, radiated emissions from an electrical drive system is charac- terized thru gray-box modelling where coupling between electrical machine phase …

Metal-Ion Doped Borate Bioactive Glasses- A Novel Direction In Minimizing Nosocomial Infections And Antibiotic Resistance, Sarah Fakher

Masters Theses

"Nosocomial infections represent a formidable challenge and induce a substantial burden on patients and healthcare systems. These infections result from the interaction of numerous pathogenic microorganisms, particularly bacteria, and lead to increased morbidity, mortality, and healthcare costs. Extensive research has been carried out to devise innovative solutions, mainly focusing on antimicrobial natural and synthetic substances. However, the proclivity of bacterial strains to form biofilms complicates treatment and elevates antibiotic resistance, prompting research into pioneering more effective and versatile antibacterial strategies. Borate bioactive glasses (BBGs) are the latest, remarkable classes of biomaterials with a wide array of medical applications, owing to …

Human Arm Stiffness Estimation Method Developed For Overground Physical Interaction Experiments: Experimental Validation And Perspectives For Future Applications, Tarani Kanth Kamma

Masters Theses

"To build a physically interactive robot for overground applications, it is crucial to first understand the biomechanics of humans underlying overground physical human-robot interaction (pHRI) tasks. Estimating human arm stiffness during overground interactive tasks is a promising first step toward this goal. For this, an arm stiffness estimation technique was developed in our previous works that consider the unique challenges involving overground pHRI, such as the need to estimate the arm stiffness from a short duration of data with fewer repetitions. In this work, our stiffness estimation method is further validated with a passive spring setup with known stiffness values, …

Groundwater Movement In Boiling Spring, Onyx Spring, Yelton Spring, Wilkins Spring, Hudgens Spring And Natural Bridge Spring, Katherin Roxana Montes Chamorro

Masters Theses

"Onyx Spring, Boiling Spring, Yelton Spring, Wilkins Spring, Hudgens Spring, and Natural Spring are located on public land in Pulaski and Phelps County, Missouri. They were selected randomly to determine groundwater movement and compare water chemistry from the springs that are connected.

Using a dye tracing method, we were able to determine the direction of groundwater flow and a water multiparameter sonde was used to characterize the water chemistry at each point of the springs. As a result, from the six springs studied only three springs are connected which are Yelton, Onyx and Boiling Spring. Regarding to water chemistry this …

Computational Fluid Dynamics Analysis Of Thermal-Hydraulic Phenomena In Nuclear Reactor Systems, Mehedi Hasan Tusar

Masters Theses

"A computational analysis of thermal-hydraulic processes in nuclear reactor systems is performed, leveraging Computational Fluid Dynamics (CFD) to advance the design and ensure the safety of nuclear reactors. Divided into two primary sections, the initial part examines thermal-hydraulic behavior in the Replacement Research Reactor (RRR) operating at 20 megawatts and evaluates potential enhancements for the Missouri University of Science and Technology Reactor (MSTR) to operate at an increased capacity of 2 megawatts from the existing 0.2 megawatts. Detailed simulations reveal insights into flow characteristics, temperature distributions, and pressure drops, highlighting the effective use of realistic and porous media modeling techniques …