Digital Commons Network^™

Modelling And Development Of An Automated Ldpe Autoclave Reactor In Cfd For Revealing Ethylene Hot Spots, Eric Turman

Masters Theses

Computational Fluid Dynamics (CFD) was employed to develop a rigorous model of a low-density polyethylene (LDPE) autoclave reactor. Different numerical settings within the solver were evaluated to minimize false diffusion and to reflect the sensitive heat generation taking place during free radical polymerization. The rigorous CFD model employed reaction kinetics, Proportional Integral Derivative (PID) automated thermal management, and a rotating stirrer shaft. Validation was carried out to determine the sensitivity to time-step size, turbulence model, and grid resolution. Data were compared to an industrial scale plant autoclave to guide the development of CFD. Time-step independence was confirmed by comparing the …

Teaching Through Screens, David Dell'osso Ritter

Masters Theses

The COVID-19 pandemic affected educational delivery dramatically, as many classes were transferred from ground to online in just a few weeks. This research explored the impact this transfer had on teachers and students. The research focused on student motivation and productivity in the online environment, as well as teacher presence in and preparedness for the online environment. The problem statement for this research is as follows: The COVID-19 pandemic responses to education diminished teacher presence resulting in a steep decline in student motivation and productivity. In addition to an extensive literature review, three case studies to better understand what had …

Examining The German Public's Response To The Third Reich's Anti-Jewish Policies, Georgetta M. Moore

Masters Theses

The anti-Jewish policies of the Third Reich progressed from anti-Jewish legislation, stripping German Jews of their rights, to systematic mass murder. Deeply rooted antisemitism and Nazi propaganda serving as a vehicle for ideology fostered an environment of approval among most of the German public for certain anti-Jewish policies such as the Nuremberg Laws. The non-Jewish, German public responses to these anti-Jewish policies by the Third Reich shifted over the course of the Nazi’s rule and during World War II. Most of the German public supported anti-Jewish legislation such as laws removing German Jews from civil service occupations because it made …

The Transfer Equity Program A Plan To Increase Baccalaureate Attainment For Students Of Color, Olivia M. Knodel

Masters Theses

The primary goal of a higher education institution is to provide students with a quality education and help them obtain a bachelor’s degree. By earning a bachelor’s degree this provide an opportunity of a social mobility. The racial institutional stratification in higher education continues to be problematic for underrepresented students and their baccalaureate attainment goals. This issue is important to address, for students of color who start at a community college and transfer to a degree granting institution. The project will explain institutional barriers that students of color face in their post-secondary transition. The project will offer specific services and …

An Examination Of Mental Health In First-Year College Students, Emily Jolin Luettke

Masters Theses

Research shows that first-year college students are likely to struggle with their transition into a higher education institution, which can lead to an influx of various mental health issues. This project explores factors that impact the adjustment to college as well as examines barriers that individuals face that keep them from seeking professional help. As mental health issues are on the rise, especially with the occurrence of the COVID-19 pandemic, it is crucial to have conversations with students on mental health. The goal is to educate students in an effort to reduce mental health stigma and share information about resources …

Mislabeled: A Study Of Generational Labels And Gen Z Stereotypes, Levi Victor Smith

Masters Theses

Generation Z is the newest cohort to be introduced in the generational cycle and has earned the attention of marketers, researchers, and the general public alike. While individuals and members of other generations have been quick to stereotype and assign labels to members of Generation Z, little research has been done to see if such labels are accurate. Therefore, the purpose of this study was to discover whether generational labels can accurately communicate the characteristics of individuals within Generation Z. This study used Henri Tajfel's and John Turner’s Social Identity Theory to examine how group membership defines self-identity in terms …

Development Of A Ppg Sensor Array As A Wearable Device For Monitoring Cardiovascular Metrics, Jose Ignacio Rodriguez-Labra

Masters Theses

Wearable devices with integrated sensors for tracking human vitals are widely used for a variety of applications, including exercise, wellness, and health monitoring. Photoplethysmography (PPG) sensors use pulse oximetry to measure pulse rate, cardiac cycle, oxygen saturation, and blood flow by passing a light beam of variable wavelength through the skin and measuring its reflection. A multi-channel PPG wearable system was developed to include multiple nodes of pulse oximeters, each capable of using different wavelengths of light. The system uses sensor fusion along with a machine learning model to perform feature extraction of relevant cardiovascular metrics across multiple pulse oximeters …

Influence Of Soil And Land Cover On Chronic Wasting Disease Prevalence In White-Tailed Deer And Mule Deer Across North America, Madison L. Miller

Masters Theses

Chronic wasting disease (CWD) is a fatal neurodegenerative disease that infects deer and is caused by a pathogenic prion. CWD is a concerning wildlife disease because it is incurable, potentially poses a risk to human health, and is spreading rapidly. CWD prions are transmitted both directly via bodily fluids and indirectly through environmental reservoirs such as soil. In this study, we investigated the influence of land cover and soil characteristics on CWD prevalence in white-tailed deer and mule deer. We acquired CWD prevalence data from seven North American regions and used ArcGIS to obtain land cover and soil characteristic data …

Short-Term 2d And 3d Geomorphic Change Detection At A Public Park On Lake Michigan Using Uas Remote Sensing Techniques, Scott Patrick Fitzgerald

Masters Theses

The high-water level of Lake Michigan (LM) in the past few years has led to significant periods of erosion and increased the risk to private property owners on the coast. To cope with this, many property owners on the coast of LM have constructed coastal protections, some opting for seawalls. Previous studies have assessed the effects of seawalls but disagreed on their impacts, and only laboratory studies were able to establish their range of influence. Using a different method to study their effects will be pertinent to understanding them.

This research aims to use a higher temporal and spatial resolution …

"The Third Power": James A. Everitt And The American Society Of Equity, Mark Kristian Myrdal

Masters Theses

The late 19th century marked a golden age for farmers’ movements in the United States. Crushing debt, deflation, increased urbanization, and industrial acceleration generated much discontent in America’s agricultural communities, and unleashed “a Populist moment” of farmer protest and organization. While the early 20th century witnessed significant economic improvement, farm organizations continued to operate and, in some cases, even thrived. Established in 1902 by seed merchant and newspaper editor James A. Everitt of Indiana, the American Society of Equity was one of the first major farmer’s movements founded in the twentieth century and helped to spread the concept of cooperative …

Living With Stuttering: Authenticity, Identity, And Mental Health, Sarah Musilli

Masters Theses

In an effort to manage stigma, some PWS attempt to conceal stuttering and pass as a fluent speaker (Constantino et al., 2017). These efforts to conceal may be counterintuitive, as concealment of stuttering is predictive of elevated distress (Gerlach et al., 2021) and decreased quality of life among PWS (Boyle et. al., 2018). Although this association exists, the factors explaining how and why it exists are unexplored. Identity conflict and feelings of in/authenticity are two potential factors that are explored in this study. Qualitative interviewing supplemented with quantitative survey data is utilized to explore the lived experiences of identity conflict …

Design And Optimization Of An Electron Cyclotron Resonance Thruster, Austen Thomas

Masters Theses

Presented in this work is the process in the design and optimization of a coaxial electron cyclotron resonance thruster. Electron cyclotron resonance thrusters are novel microwave-based thrusters which possess select technological advantages over mature electric propulsion concepts such as being electrodeless and only requiring a single power source. The thruster constructed in this work is a coaxial configuration and is termed the Western electron cyclotron resonance thruster. Thruster dimensions were optimized based on past experimentation completed with ECR thrusters. In an attempt to enhance the microwave plasma coupling of the coaxial thruster design three different antenna configurations were considered: a …

Instructor Selection And Use Of Virtual Field Experiences In College Geoscience Course, Kristen Foley

Masters Theses

Virtual Field Experiences (VFEs) are a growing supplement and gateway to traditional fieldwork in the geosciences. With VFEs becoming more accepted for use in college geoscience courses, how instructors find and choose VFEs for their students is critical to creating greater accessibility and future resources. VFEs that are not easily accessed by instructors may go unused, and the effort put into making them would have been wasted. This phenomenological descriptive study utilized five focus groups of college geoscience instructors in the United States. Each 1-to-1.5-hour focus group session of 3-7 participants took place on video conferencing software, which was recorded …

Uplifting Voices: Implementing A Heritage-Based Civil Rights Program In The United States Forest Service, Amanda Jo Campbell Crawford

Masters Theses

The United States Forest Service holds in public trust hundreds upon thousands of historically significant sites. For decades, the management of these special places has focused on basic site identification and protection to meet legal compliance measures for Section 106 of the National Historic Preservation Act. Standard practices within the agency led to cultural sites being identified on the ground in a cursory fashion, but with little research or follow up into the history of the site of the people that had created and occupied it. Sites reflecting the identity, history, or material culture of People of Color were especially …

Dynamic Maneuvers For Satellite On-Orbit Servicing Utilizing Novel Continuum Robotics: Development & Experimentation, Nathan Dalton

Masters Theses

Robotic on-orbit servicing is a developing technology that seeks to increase the longevity and repairability of faulty or aging resident space objects. In this research, the development of a flexible continuum manipulator for a small satellite system that performs low-complexity on-orbit servicing or debris removal is presented. Derivations of manipulator kinematics are described in detail, a non-linear control scheme has been developed, and the accuracy and servicing applications for the prototype are evaluated and discussed. The manipulator has been tested on an air-bearing dynamics simulator, and the results are extensively analyzed. System recommendations and future work suggestions are presented.

One Shell Of A Problem: Cumulative Threat Analysis Of Male Sea Turtles Indicates High Anthropogenic Threat For Migratory Individuals And Gulf Of Mexico Residents, Micah Ashford

Masters Theses

Human use of oceans has dramatically increased in the 21st century, with some of the highest rates of change found within the Gulf of Mexico and Caribbean. Sea turtles are particularly vulnerable to anthropogenic stressors in the marine environment as they make lengthy migrations between foraging and breeding sites often along coastal migration corridors. Sea turtles face severe population pressure from humans, yet little is known about how movement and threats interact specifically for male sea turtles. To better understand male sea turtle movement, and the threats they encounter within their expansive ranges, we tagged 40, adult male sea turtles …

Integrating Temperature Dependence Into A Microstructure-Sensitive Fatigue Model For Titanium Alloys, Jared Michael Darius

Masters Theses

This work seeks to integrate temperature dependence into a microstructure-sensitive fatigue model for titanium alloys produced by both extrusion and electron beam melting (EBM) additive manufacturing, revising and enhancing the MultiStage Fatigue (MSF) model as the foundational model framework. Traditional fatigue modeling has required design engineers to conservatively use a lower-bound estimate of fatigue life predictions given a statistically significant spread of experimental data that can span up to two or sometimes three orders of magnitude for a given test condition. This variation in fatigue data has since been accounted for with the advent of the MSF model, linking individual …

Comparison Of Bigheaded Carp Reproduction In Tributaries Of The Illinois And Wabash Rivers, David J. Yff

Masters Theses

Understanding environmental conditions that support bigheaded carp (Hypophthalmichthys sp.) reproduction in tributary rivers provides key predictions of their invasion throughout the United States. Past research, primarily in larger order rivers, identified factors such as discharge, temperature, and turbidity as main environmental drivers of bigheaded carp reproduction. I used the variable hydrologic conditions between the Illinois and Wabash Rivers to compare environmental conditions between tributaries of each basin, determine which conditions influence bigheaded carp reproduction in tributaries, and predict tributaries likely to support bigheaded carp reproduction. Three tributaries of the Illinois and Wabash Rivers were sampled for ichthyoplankton from …

Student Affairs Professionals As Tempered Radicals: Lessons On Action And Advocacy, Devin A. De Both

Masters Theses

Modern universities are intricate organizations with many stakeholders each with their own goals and objectives. In a time of resource scarcity, student affairs professionals are tasked with advocating on behalf of their students, staffs, departments, and priorities against more solvent operations. Effective managers and administrators must align their priorities with other actors on campus and in accordance with institutional values. This study asked how professionals engage in the advocacy process, including the strategies that they use. Utilizing the tempered radicals perspective, this qualitative study was conducted through four interviews with experienced senior level student affairs professionals.

A Variable Node Optimization Model For Byzantine Fault Tolerant Systems, Ian Robert Fulton

Masters Theses

“Byzantine Fault Tolerance (BFT) has been a major subject of study over the last two decades with increasing societal dependance on secure, correct, and reliable computer systems and online services. This research presents a model for high-level optimization of emerging systems that rely on these BFT algorithms and use a variable numbers of decision nodes. The model highlights the relationship between the security of a system and its efficiency. Two experiments were performed to determine system performance by varying the number of compromised nodes, decision nodes, and total nodes. They examine the probability that a transaction will be compromised based …

State Level Trends In Renewable Energy Procurement Via Solar Installation Versus Green Electricity, Eric Michael Hanson

Masters Theses

“In the past 5 years, consumer options for procuring renewable energy have increased, ranging from rooftop solar installation to utility green pricing to Community Choice Aggregation. These options vary in terms of costs and benefits to the consumer as well as grid integration implications. However, little is known regarding how the presence of a wide range of options for utility-scale renewable procurement affects demand for distributed residential solar installations. In theory, there are three possible relationships, (1) positive correlation, where utility-scale and distributed resources complement each other to increase overall production, (2) negative correlation, where utility-scale and distributed resources are …

Particle Swarm Optimization For Critical Experiment Design, Cole Michael Kostelac

Masters Theses

“Critical experiments are used by nuclear data evaluators and criticality safety engineers to validate nuclear data and computational methods. Many of these experiments are designed to maximize the sensitivity to a certain nuclide-reaction pair in an energy range of interest. Traditionally, a parameter sweep is conducted over a set of experimental variables to find a configuration that is critical and maximally sensitive. As additional variables are added, the total number of configurations increases exponentially and quickly becomes prohibitively computationally expensive to calculate, especially using Monte Carlo methods.

This work presents the development of a particle swarm optimization algorithm to design …

Predicting Radiated Emissions From A Cable Harness Through Component Level Tests, Fuwei Ma

Masters Theses

“In this work, a procedure is developed to predict the radiated emissions from a cable harness using component-level tests. Direct measurement on the engine control unit is utilized to accurately characterize the equivalent common mode source voltages and impedance associated with the device. The cable harness geometry is reduced using the equivalent cable bundle approach by lumping wires according to the source and load impedance compared with characteristic impedance of the harness, which dramatically reduces the measurement effort and allows practical 3D full-wave simulation of the radiated emissions. Radiated emissions are predicted from an engine control unit (ECU) and an …

Zinc Plating From Alkaline Non-Cyanide Bath, Abdul J. Mohammed

Masters Theses

“Alkaline non-cyanide zinc plating baths are preferred when trying to avoid the toxicity of cyanide baths or corrosivity of acid baths. Without additives, alkaline zincate baths produce powdery non-adherent deposits which have no use in commercial plating. Additives must be added at optimum concentrations to produce adherent, bright and uniform zinc deposits. In this study electrochemical tests were used to determine effects of additives on cathodic polarization, throwing power and morphology of deposits. Current density distribution in a unique bath of 37.5 g L^-1 Zn and 210 g L^-1 NaOH was modelled using COMSOL and validated two plating …

Study Of Contamination Resulting From Historical Mining Within The Old Lead Belt: Mineral Fork Watershed, 2021-2022, Tessa Nicole Mortensen

Masters Theses

“The Old Lead Belt in Missouri has been mined extensively over the past two hundred years, and with historical mining practices often not meeting modern environmental protection standards many areas have significant soil and water contamination as a result. This study focuses on the Mineral Fork River’s watershed in Washington County, Missouri, which includes portions of four separate Superfund sites. In this study, we exam the impact of historical mining on the health of alluvial systems, as evaluated by lead, zinc, and barium (barite) concentrations in the suspended and sediments within tributaries of the Mineral Fork River system. To relate …

Characterization Of Cermet Fuel For Nuclear Thermal Propulsion (Ntp), James Floyd Mudd

Masters Theses

“A manned flight to Mars is met with many technical challenges, not the least of which is the development of propulsion technology capable of moving a transit vehicle from Earth orbit to Mars orbit. NASA is investigating Nuclear Thermal Propulsion (NTP) as a way of reducing flight time and providing the option for a mid-mission abort. NTP, which uses a high temperature nuclear reactor to heat a propellant, requires advanced fuel materials capable of withstanding temperatures well in excess of 2000 K. Among the fuel options are ceramic metal (cermet) composites composed of refractory metals and Ultra-High Temperature Ceramics (UHTCs). …

Industry 4.0 Remanufacturing: A Novel Approach Towards Smart Remanufacturing, Prashansa Ragampeta

Masters Theses

“Smart remanufacturing has become more popular in recent years as a result of its multiple benefits and the growing need for society to encourage a circular economy that leads to sustainability. One of the most common end-of-life (EoL) choices that can lead to a circular economy is remanufacturing. As a result, at the end-of-life stage of a product, it is critical to prioritize this choice over other accessible options because it is the only recovery option that retains the same quality as a new product. This work focuses on the numerous technologies that can aid in the improvement of smart …

Adsorption Of Arsenic Onto River Sediments, Leticia Augusta Dos Santos Ferreira

Masters Theses

“Previous studies have noted the relationship between shallow groundwater rich in sodium (Na) and bicarbonate (HCO₃) and elevated levels of dissolved arsenic. However, most experimental work on arsenic adsorption in the presence of HCO₃ and differing Na/Ca ratios has proven difficult to extrapolate to natural systems because of differences in tested mineral compositions and component concentrations. In this study, I performed a series of adsorption experiments using river sediments to evaluate the influence of HCO₃ and monovalent/divalent cations on the extent of arsenic adsorption onto natural sediment in groundwater.

Batch adsorption (kinetics, equilibrium, and metal loading) …

Optimization And Modeling Of Esd Protection Devices, Li Shen

Masters Theses

“Transient voltage suppressors (TVS) are used to protect ICs (integrated circuits) against overvoltage, ESD (Electrostatic Discharge), inductive load switching, and even lightning strikes. In this research, a transient behavior model framework for ESD protection devices is used for modelling four different types of TVS (non-snapback, snapback, spark gap like device and varistor). The System-Efficient ESD Design (SEED) methodology is utilized to strengthen the trust in the model framework by efficient simulation of ESD interaction of the off-chip ESD protection devices with the IC ESD protection device and associated measurement data.

Improvements in the TVS transient response, accounting for conductivity modulation, …

Validation Of Athlet-Cd With Cora-28 Test, Murat Tuter

Masters Theses

“Following the incidents at Chernobyl and Fukushima, severe accidents at nuclear power plants (NPP) have become a global concern. These accidents generally occur because of a failure in the reactor cooling system (RCS) and result in the melting of the reactor core and fission product release. This event is mostly caused by a LOCA, loss of flow accident, station blackout or loss of heat sink. During a severe accident, generation of hydrogen as a result of steam-zircaloy fuel cladding is a significant safety concern. To better understand and prevent the hydrogen generation issue, safety related experiments and safety related codes …