Digital Commons Network^™

Comparison Of Reynolds-Averaged Navier-Stokes Turbulence Models For Simulating Boundary Layers In Hypersonic Flows, Jorge-Valentino Kurose Bretzke

Masters Theses

“This study describes the use of Computational Fluid Dynamics (CFD) codes to simulate hypersonic boundary layers using several different turbulent closure models and comparing Reynolds-Averaged Navier-Stokes (RANS) simulations against Direct Numerical Simulations (DNS) of similar test cases. The test cases in this study consist of a flat plate in a Mach 8 freestream with a zero pressure gradient and wall recovery ratio of 0.48, as well as a Mach 8 axisymmetric nozzle also with a cold wall. The RANS models used in this study are the Spalart-Allmaras model, Baldwin-Lomax model, Menter K-Omega Baseline and Menter K-Omega Shear Stress Transport models. …

Characterization Of A Plasma Source Simulating Solar Wind Plasma In A Vacuum Chamber, Blake Anthony Folta

Masters Theses

"The United States has set an aggressive time line to not only return to the Moon, but also to establish a sustained human presence. In the Apollo missions dust was a significant factor, but the duration of those missions was short so dust and surface charging were problems, but they did not pose an immediate threat. For a long-term mission, these problems instead become incredibly detrimental. Because of this, research needs to be conducted to investigate these phenomena so that mitigation techniques can be developed and tested. To this end, this thesis serves to demonstrate the Gas and Plasma Dynamics …

On The Investigation Of Hot Tearing Behavior Of Continuous Cast Steel, Yanru Lu

Masters Theses

”Hot tearing has long been recognized as a major problem that plagues the development of the continuous casting process and results in low-quality products. Understanding of the mechanisms and the required conditions for the hot tearing formation is important for industries but has not been well-established yet. Thus, this research focuses on the hot tearing issue observed in continuous cast steel, by providing a summary of the current research progress and then introducing a new laboratory method to determine the thermo-mechanical properties relevant to hot tearing of different steel grades under different solidification conditions. In this method, an apparatus was …

The Role Of Tectonic Inheritance, Plate-Reorganization, And Magma Flare-Ups In The Evolution Of The Sevier Orogeny, J. Daniel Quick

Masters Theses

"The temporal and spatial distribution of strain associated with the Sevier Orogeny in western North America is significantly different in the southern end of the belt, at the latitude of Las Vegas, than further to the north at the latitude of Salt Lake City. Until this study, reasons for these differences were speculative as a lack of thrust kinematic data in the intervening region hindered along strike correlation across the belt. A crystallization age of 100.18 ± 14 0.04 Ma was determined for zircons extracted from a recently recognized ash fall tuff near the base of the synorogenic Iron Springs …

How Christian College Student Leaders Discover Purpose, Emmanuel Ayiku

Masters Theses

Among college students, research has revealed that 76% of them reported that they search for meaning in life (Dunn & Hammer, 2015). Spirituality is one specific way in which students begin their search for meaning. A qualitative approach was used to examine the perspectives of how six Christian college student leaders from three different campus ministries found their purpose. By examining and understanding purpose from one subset of religious students who serve in a leadership position, we may gain insight into the interplay of meaning-making, purpose, and leadership. This study concluded that faith or spirituality played an important role in …

Shaking The Ceiling: First Leadership Role Attainment For Collegiate Women, Elizabeth J. Siecinski

Masters Theses

Using qualitative research methodology, factors and barriers influence leadership role attainment for collegiate women were explored and examined. The study used semi-structured interviews with four participants to look at factors influencing leadership attainment and why women decide to lead. The researcher identified factor before and after college that impacted a women’s decisions to lead, and her ability to attain a role. Challenges and barriers that women face in their leadership role attainment were also found. Overall, the research found that due to barriers and challenges women struggle to lead authentically, and that they see leadership as way to contribute to …

“That New Africa Is Ready To Fight Its Own Battles": Kwame Nkrumah, The United States, And The Quest For A Modern Ghana, 1957-1966, Godwin Gyimah

Masters Theses

This project examines the United States-Ghana relationship and how the relationship transformed Ghana, 1957-1966. African leaders such as Dr. Kwame Nkrumah had declared: "That new Africa is ready to fight its own battles and show that after all, the black man is capable of managing his affairs." Despite the non-alignment philosophy, Ghana was not neutral regarding the West and East blocs rivalry. The thesis argues that it was through the United States' government and private firms' contributions that Ghana was able to achieve the mark of a modern nation through industrialization, universal education, and the expansion of international trade economy. …

A Study On Real-Time Database Technology And Its Applications, Geethmi Nimantha Dissanayake

Masters Theses

No abstract provided.

Monitoring Temporal Trends In Catostomidae Larvae In Large Sized River Tributaries, Kellie Nicole Hanser

Masters Theses

Large river ecosystems can support a complex network of tributaries that provide optimal habitat for fish reproduction. Anthropogenic alteration of rivers and tributaries has been shown to have adverse effects on river fish communities, but few studies have focused on the effects river regulation may have on the reproduction of native suckers (Family Catostomidae). In this study, I evaluated differences in biotic and abiotic factors associated with catostomid reproduction between tributaries of an altered and free-flowing river. I conducted ichthyoplankton sampling using drift nets and larval push nets in tributaries of the Illinois River, which is regulated for navigation, and …

Identification And Analysis Of Genes With Differential And Tissue-Specific Expression In Poplars, Bailey Mitchell

Masters Theses

Poplars have become one of the most frequently studied plant species for their applications in biotechnology, commercial benefits, and ecological importance. Microarray analysis is commonly used to analyze differential gene expression in many organisms. Investigations have examined differential gene expression and performed functional analyses on a single tissue or organ within poplar trees or a closely related set of tissues and organs, but usually do not broadly analyze gene expression across a large number of tissues and organs in poplar. This thesis work aims to generate data on the most differentially expressed genes for the major groups of tissues and …

Bigheaded Carp Spatial Reproductive Dynamics And Population Genetics In Large River Tributaries, Samuel J. Schaick

Masters Theses

Fisheries managers are devoting considerable effort, time, and funding towards limiting the spread of invasive Bighead and Silver (bigheaded) Carp. A better understanding of factors that influence spatial patterns of bigheaded carp reproduction can help fisheries managers prevent their spread. To examine factors that influence spatial patterns of reproduction, we sampled ichthyoplankton using drift nets and larval push nets in three tributaries of the Illinois and Wabash Rivers March-September 2016-2018. We compared relative abundances of bigheaded carp eggs and larvae among tributaries using catch per unit effort (CPUE). Abiotic data were analyzed from individual study tributaries and pooled among tributaries …

A Cloning Strategy For Expression Of Fungal Hemicellulases In Plant Systems, Amer Alrudayan

Masters Theses

Lignocellulosic biomass is notoriously difficult to deconstruct into lignin, hemicellulose, and cellulose fractions without the use of biochemical, chemical, and/or mechanical pretreatments. These pretreatment strategies add operational cost and in some cases produce hazardous waste that poses health and safety risks. Direct biological pretreatment from biomass-degrading bacteria and fungi may significantly reduce the costs and risks associated with these traditional strategies due to the innate ability of these organisms to modify plant cell walls. An additional measure that could further reduce the expenses associated with lignocellulosic biomass fractionation is genetic modification of the lignocellulosic feedstocks, which can be accomplished by …

The Transcriptome Response Of The White-Rot Fungus Trametes Versicolor To Wild-Type And Lignin-Modified Hybrid Poplar, Anbarah Alzabaidi

Masters Theses

Plant biomass is a renewable and sustainable feedstock for biofuel production that can reduce societal dependence on fossil fuels. However, the production of liquid biofuels from the non-starch (i.e. lignocellulosic) material through fermentation technology is limited due to the complexity of the cell wall structure. This necessitates the use of chemical, thermal, and/or mechanical pretreatment technologies, which adds significant capital, operational, and environmental costs. Biological pretreatment strategies have the potential to mitigate these expenses by harnessing the innate ability of specialized bacteria and fungi to deconstruct lignocellulose. White-rot fungi (e.g. Trametes versicolor) have been shown to be …

Exploring Secondary Students’ Abilities In Judging The Credibility Of Digital Content On The Internet, Katie Dailey

Masters Theses

The shift from print to digital environments has created an opportunity and responsibility for educators to focus on instructional planning and practices that reflects the growing complexity of online texts students helping to ensure that their students are information literate. The purpose of this qualitative study is to explore the how 83 eleventh grade high school English students judge the credibility of information on the internet. The researcher used methodological triangulation to qualitatively analyze by comparing and aligning data from the survey results, observations of students during class discussions, responses to class assignments, and the quality ratings of students’ think-aloud …

Shock Wave Propagation Behavior At Corners And Crosscuts In Five Small-Scale Tunnel Scenarios, David Pierre Doucet

Masters Theses

"Shock wave propagation in tunnels and other enclosed environments is substantially more complicated than in an open-air or even a surface detonation. There is still much to learn about how shock wave properties change as a wave propagates in an enclosed space, such as a mine tunnel, inside of a building, or city street. The geometry of the enclosure will have a large role in the propagation of the shock wave. This means that many different tunnel designs must be studied. This work tested five different designs using a modular small-scale model. The scenarios tested were Straight-line, Single Turn, Around …

Games For Organizational Training: Gamer Motivation Profile And Organizational Training Climate Effect Of Trainee Preference For Gamified Training, Brooke-Nicole Woods Ruffin

Masters Theses

“Gamified training is often utilized in organizations as a way to revamp their training and gain the attention of their employees. However, this training is expensive, and research is needed to help ensure that this training delivery is successful. In this study, first an individual’s gamer motivation profile is compared with learning outcomes that share the same elements. This was completed to determine if the elements that they looked for in playing video games were in alignment with those same elements in training In addition, it was explored whether the preference for participating in video games based on an individual’s …

Micro-Analysis Of Contaminants In Suspended Load And Bank Deposits From The Mineral Fork Creek Watershed In Potosi, Missouri, 2019-2020, William Joseph Miller

Masters Theses

”There are rising concerns pertaining to water contamination produced by toxic heavy metal contaminants such as lead and zinc. For this study, lead, zinc, and barite are three identified contaminants currently threatening Missouri water supplies. A microanalysis of the amounts of lead, zinc, and barite in the water of Mineral Fork Creek was conducted, involving both field and laboratory work. The purpose of the study was to determine the levels of lead, zinc, and barite contaminants, contributing to Big River, by Mineral Fork Creek, in Potosi Missouri, Washington County.

This research study uses a quantitative micro-analysis approach to determine the …

Values Of Artificial Intelligence In Marketing, Yingrui Xi

Masters Theses

“Artificial Intelligence (AI) is causing radical changes in marketing and emerging as a competent assistant supporting all areas of the marketing field. The influences and impacts AI has created in various marketing segments have aroused much interest among marketing professionals and academic scholars. Comprehensive and systematic studies on the values of AI in marketing, however, are still lacking and the existing literature fragmented. This research provides a comprehensive review of the existing literature in the relevant fields as well as a series of systematic interviews using the Value-Focused Thinking approach to understand the values of AI in marketing. This research …

Optical Fiber Based Integrity Test Of Civil Engineering Materials: Numerical Analysis, Ruoyu Zhong

Masters Theses

“Major advancement in Civil Engineering cannot be accomplished without the help of sensors. Among different types of sensors, fiber-optic sensor is known for its light weight, high accuracy, resolution, immunity to electromagnetic interference, and resistance to harsh environment. This research mainly focuses on fiber-optic sensor application on concrete structures as temperature sensor. Thermal Integrity Profiling (TIP) is a non-destructive integrity testing method which makes use of the hydration heat from the concrete curing process to detect defects within a drilled shaft. Any defect of concrete could result in a temperature anomaly in a drilled shaft. The accuracy of the current …

Additive Manufacturing Of Linear Shaped Charges To Address Run Up And Run Down Phenomena, Jason Ho

Masters Theses

”A shaped charge is an explosive device used to focus detonation energy in a desired direction. Additive Manufacturing (AM) can allow greater design freedom and geometric complexity for the liner portion of the shaped charge.

In this work, the following hypotheses were tested: 1) Adjusting the initial apex angle of a linear shaped charge liner reduces the amount of run up that occurs, and 2) implementing a backstop at the end of a linear shaped charge liner reduces the amount of run down that occurs.

Linear shaped charge liners with a continuously changing apex angle were created with additive manufacturing. …

An Intricate Ensemble : The Art-Science Of An Ecological Imaginary For The Anthropocene Epoch, Alyce Santoro

Masters Theses

The contradictions inherent in European Enlightenment-based “logics” that externalize humans from “nature” were a concern for the Romantic Naturalists, Dadaists, and Surrealists. More recently, some in the environmental humanities and socio-ecologically-concerned arts and sciences have also posed challenges to anthropocentric, hierarchical, positivist modes of thought. I suggest that by engaging the ludic, imaginative, and collaborative while bearing the empirical in mind, dualisms (such as objective and subjective, individual and collective) dissipate, and existence as a dialectical state of intricate ensemble can be revealed. In light of catastrophic disruption to Earth’s life-sustaining processes by exploitative forms of human activity, I argue …

Portable Electrochemical System For Flexible Hybrid Electronics, Anthony Joseph Hanson

Masters Theses

This work focuses on the fabrication and design of a portable electrochemical sensing system for flexible hybrid electronic (FHE) sensors. A three-electrode chemical sensor was fabricated using copper tape on polyethylene terephthalate (PET) substrate, using laser etching process. An electronic circuit was designed to measure the sensor response through electrochemical techniques to detect different concentrations of glucose. The device was calibrated to give the user a concentration value in 5 seconds. The system was also designed to preform tests such as cyclic voltammogram and chronoamperogram for various chemicals. A Bluetooth Low Energy module was used to wirelessly transmit the results …

A Comparative Study On The Stability And Degradation Of Perovskite Solar Cells, Jyotiska Chakraborty

Masters Theses

This study aims to investigate the environmental factors that affect the performance and longterm stability of the perovskite solar cells (PSCs). PSCs are based on organo-metallic halides (perovskites) that act as a light-sensitive compound that produces excitons when placed under the light. However, PSCs have a limited operating lifetime due to the degradation of the perovskite layer. There are many factors like moisture, UV light, and temperature that lead to the degradation of the perovskite layer. From the literature review, it was found that the PSCs do not degrade with the presence of oxygen in a dry and dark environment. …

A Cfd Study On The Performance Of High Speed Planing Hulls, Mowgli J. Crosby

Masters Theses

Most high speed water craft are able to achieve high speeds through the use of a planing hull. Planing hulls use hydrodynamic forces to lift a portion of the vessel out of the water, reducing drag, and allowing for greater speeds. Determining the flow around such vessels is traditionally achieved using a scale model in a tow tank. The purpose of this study was to analyze the performance of a high speed planing hull determine the effects of several geometric features using computational fluid dynamics rather than traditional experimentation. The goal was to determine the best configuration to ensure the …

The Design And Development Of A Device To Assist In Boosting Patients, Taylor A. Rieckhoff

Masters Theses

A common task a nurse is required to perform is called boosting patients. Boosting a patient is defined as lifting or sliding a patient back up in the bed after having slid down (Mannheim, Zieve, & Conaway, 2017). The current method for boosting patients involves a minimum of two personnel and an 11-step process. The 11-step process requires the person to manually lift and pull the patient using an existing half sheet on the bed (Mannheim, Zieve, & Conaway, 2017). Patients who cannot move or support themselves are moved every two to six hours or upon request (Bihn, Rieckhoff, Burkman, …

Radio Direction Finding Using Pseudo-Doppler For Uav-Based Animal Tracking, Anup Karki

Masters Theses

Radio Direction Finding (RDF) is commonly used for low cost tracking and navigation systems. However, for a low cost application and mobility, the design constraints are highly limited. Pseudo Doppler (PD) can improve RDF capabilities without being cost prohibitive. This work entails the analysis of PD RDF and its potential use for Unmanned Aerial Vehicles (UAV) that are currently employed in wildlife research animal tracking. PD is based on the doppler effect or doppler shift. The doppler effect works like a frequency modulator that increases or decreases the observed frequency depending on whether a signal source is approaching or receding …

Modeling And Improvement Of Electronic Waste Collection System: Case Study At Grand Valley State University, Quang Tran Nhat Nguyen

Masters Theses

Accelerated and advanced development of the electronics industry in the 21st century is creating the rapid obsolescence of electrical and electronic equipment. This causes one of the largest and unstoppable waste streams called electronic waste (e-waste). There have been obstacles in e-waste recycling, including the existence of the informal sector such as peddlers (a larger issue in developing countries) and insufficient consumer awareness. The ideal e-waste recycling system would be able to overcome these obstacles. To establish an effective e-waste recycling system, the first important step is to implement an e-waste collection system. To implement an e-waste collection system, many …

Differentiating Epileptic From Psychogenic Nonepileptic Eeg Signals Using Time Frequency And Information Theoretic Measures Of Connectivity, Sarah Barnes

Masters Theses

Differentiating psychogenic nonepileptic seizures from epileptic seizures is a difficult task that requires timely recording of psychogenic events using video electroencephalography (EEG). Interpretation of video EEG to distinguish epileptic features from signal artifacts is error prone and can lead to misdiagnosis of psychogenic seizures as epileptic seizures resulting in undue stress and ineffective treatment with antiepileptic drugs. In this study, an automated surface EEG analysis was implemented to investigate differences between patients classified as having psychogenic or epileptic seizures. Surface EEG signals were grouped corresponding to the anatomical lobes of the brain (frontal, parietal, temporal, and occipital) and central coronal …

Impacts Of Shoreline Restoration And Source Of Nutrient Enrichment On Macrophytes And Epiphytic Algal Communities, Paige Marie Kleindl

Masters Theses

Macrophytes and their epiphytic algal communities are integral for optimizing littoral ecosystem functioning in lakes. Epiphytic algae’s placement on the plant’s surface can reduce light and nutrient availability (i.e., nitrogen and phosphorus) for the host macrophyte. Macrophyte and epiphytic algal proximity complicates these primary producer group interactions and responses to bioavailable nutrients in the water column or porewater. For example, epiphytic algae may have a competitive advantage over surface water nutrients compared to macrophytes, which may have a competitive advantage over porewater nutrients via root systems.

Muskegon Lake’s industrial history and designation as an Area of Concern prompted shoreline restoration, …

Assessing The Impact Of 3d Printed Terrain On Teaching Topography In Introductory Earth Science Labs, Jay Alan Cockrell

Masters Theses

Learning to effectively read topographic maps is challenging for students, as these maps contain 3D representations of terrain displayed on a 2D surface map. This project assessed student learning when 3D terrain printed from a portion of the laboratory quadrangle map currently in use was introduced into an earth science course for non-science majors. Using a quasi-experimental design with nonequivalent groups across two semesters, performance on the Modified Topographic Map Assessment (MTMA) administered as a pre- and posttest was used to compare learning outcomes between the traditional lab and the 3D print lab intervention. Students in the traditional (n = …