Digital Commons Network^™

The Relationship Of English Language Scores On International Students' Academic Success, Rebekah Shbeeb

Electronic Theses and Dissertations

International graduate students at the University of Central Florida (UCF) are not completing graduate programs at the same rate as domestic graduate students. One of the main differences in the admissions process for international graduate students compared to domestic students is the English language test requirement. The purpose of this study was twofold: to test if the Test of English as a Foreign Language (TOEFL) or the (International English Language Testing System) IELTS scores have any statistically significant linear relationships to international graduate students' academic success as defined by their cumulative grade point average (CGPA). Secondly, this study sought to …

Investigation Of Ps-Pvd And Eb-Pvd Thermal Barrier Coatings Over Lifetime Using Synchrotron X-Ray Diffraction, Matthew Northam

Electronic Theses and Dissertations

Extreme operating temperatures within the turbine section of jet engines require sophisticated methods of cooling and material protection. Thermal barrier coatings (TBCs) achieve this through a ceramic coating applied to a substrate material (nickel-based superalloy). Electron-beam physical vapor deposition (EB-PVD) is the industry standard coating used on jet engines. By tailoring the microstructure of an emerging deposition method, Plasma-spray physical vapor deposition (PS-PVD), similar microstructures to that of EB-PVD coatings can be fabricated, allowing the benefits of strain tolerance to be obtained while improving coating deposition times. This work investigates the strain through depth of uncycled and cycled samples using …

Hurricane Imaging Radiometer (Hirad) Tropical Rainfall Retrievals, Abdusalam Alasgah

Electronic Theses and Dissertations

The Hurricane Imaging Radiometer (HIRAD) is an airborne passive microwave remote sensor, developed to measure wind speed and rain rate in hurricanes. This dissertation concerns the development of a signal processing algorithm to infer tropical rainfall from HIRAD radiance (brightness temperature, Tb) measurements. The basis of the rain rate retrieval algorithm is an improved forward microwave radiative transfer model (RTM) that incorporates the HIRAD multi-antenna-beam geometry, and uses semi-empirical coefficients derived from an airborne experiment that occurred in the Gulf of Mexico off Tampa Bay in 2013. During this flight, HIRAD observed a squall line of thunderstorms simultaneously with an …

More Guns, Less Butter, And Officers At The Table: Understanding The Nexus Between The Military's Integration Into Politics And Resource Allocation In Democracies And Non-Democracies, Salah Ben Hammou

Electronic Theses and Dissertations

The civilianization of government is often seen as a necessary prerequisite for successful democratization and healthy civil-military relations. This thesis explores the impact of integrating the military into political decision-making on the distribution of "guns" and "butter" – military spending and social spending - across dictatorships and democracies. Whereas a general consensus suggests that autocracies allocate greater goods to the military and fewer goods to the general public relative to democracies, an understudied variable is the military's integration into politics in both democracies and autocracies. Given that military elites have greater incentives relative to civilian elites to prioritize military spending …

Raising Roma Voices: An Insider Examination Of American Roma Realities, Resistance, And Revaluation, Sabrina Marks

Electronic Theses and Dissertations

A vast scholarship has been dedicated to examining the discrimination racial and ethnic minorities endure in the United States. Research has also shown racial and ethnic minorities work to resist discrimination via various social processes. One ethnic minority group absent from the literature is the American Roma, more commonly known as Gypsies. Therefore, this study aimed to gain insights into the situation of the American Roma, including the discrimination they endure and the resistance tactics they employ. In-depth semi-structured interviews were conducted with 31 native-born American Roma adults during the course of this insider study. Participants reported experiencing discrimination in …

Artificial Magnetism And Topological Phenomena In Optics, Midya Parto

Electronic Theses and Dissertations

Recent years have witnessed intense research activities to effectively control the flow of photons using various classes of optical structures such as photonic crystals and metamaterials. In this regard, optics has benefited from concepts in condensed matter and solid-state physics, where similar problems concerning electronic wavefunctions arise. An important example of such correspondence is associated with the photon dynamics under the effect of an artificial magnetic field. This is especially important since photons, as neutral bosons, do not inherently interact with magnetic fields. One way to mitigate this issue is to exploit magneto-optical materials. However, as is well known, using …

'Let Me Lock It Up': A Rhetorical Exploration Of Identity And An Emergent Counterpublic Within The Youtube Beauty Community, Rachel Street

Electronic Theses and Dissertations

In light of calls to study digital composition outside of school-based domains (e.g. Yancey), this project specifically explores a counterpublic in the YouTube beauty community that has arisen in response to the encroachment of and attempts to institutionalize the space. Utilizing iconographic tracking and rhetorical analysis, this study illuminates a network of discourse geared toward a more responsible and educated consumption of makeup and participation within the beauty community. This study found that within the beauty community, a counterpublic has formed in response to a more commodified, product-centered public sphere that has dominated the space and is most associated with …

A Narrative Research Study Of Self-Selected Tracking On Motivation In 10th Grade English Language Arts Classes, Audra Greuel

Electronic Theses and Dissertations

The practice of tracking has had longstanding negative impacts on students, especially students in lower academic tracks. This research suggests that tracking develops the themes of a narrative of deficit through inequality and exclusion and impedes student motivation due to the negative implications. A common finding of outside research studies was that of disapproval for the current school organizational structure of tracking due to the negative consequences on students. Furthermore, several research studies developed an outline of positive ways to advocate for a unifying system of educational change. Educational leaders should heed the suggestions of researchers to promote changes within …

A Mixed-Method Examination Of The Impact Of Academic, Social, And Personal-Emotional Adjustment On The English Performance Of Arabian Gulf Students Studying In American Intensive English Programs, Mais Flaieh Hasan Al Jabbawi

Electronic Theses and Dissertations

The current study identifies and discusses the adjustment challenges facing Arabian Gulf Students (AGSs) that may affect their English performance (EP) in intensive English programs (IEPs) in the United States. The current study uses student departure theory to lead the theoretical framework and incorporates Student Adaptation to College Questionnaire (SACQ) and Social Integration Questionnaire (SIQ) to lead the methodology of this study. The mixed-method investigation with multi-location sampling examined 160 AGSs, enrolled full-time in different IEPs in the U.S. during the spring semester of 2019. The AGSs participants were from Iraq, Kuwait, Saudi Arabia, Qatar, Bahrain, the United Arab Emirates, …

Cultural Responsiveness And K-12 English Learners: Exploring Policy And Implementation Fidelity, Lauren Raubaugh

Electronic Theses and Dissertations

This critical policy analysis and collective case study, informed by ethnographic techniques, involved reviews of twelve Florida school district ESOL policies (included within the 2016-2019 District English Language Learner Plans, required of all Florida districts to complete) whose English learner (EL) populations met or exceeded ten percent (10%) of their total enrollment. A priori coding of these policy documents was conducted using nine criteria pulled from the literature on culturally responsive practice (CRP), which served as the theoretical framework for the study. Subsequent observations and practitioner interviews within two schools from the same district were conducted in order to ascertain …

A Comparative Study Of Two Models Of Presenting Phrasal Verbs, Nagham Majeed

Electronic Theses and Dissertations

Learning phrasal verbs (PVs) is of vital importance in both written and spoken English, especially for those English learners who must use English as a second language (ESL) in their daily interactions with proficient speakers. This study focused on two particles (out and in) in exploring a more effective model for presenting PVs in an ESL context. PVs are the focus of this empirical study because they are an essential component of English vocabulary but are typically regarded as very difficult for ESL students to master. This study used a quasi-experimental design to compare the effect of instruction through image-schematic …

Laxity Of The Hip Capsule In Natural And Posteriorly Implanted Specimens, Luke Storer

Electronic Theses and Dissertations

The hip capsule consists of ligament tissue that surrounds the hip joint, providing stability to ensure proper alignment, prevent dislocation, and facilitate proper joint function. The objective of this study was to characterize the torque-rotation response of the natural and posteriorly implanted hip capsule in healthy cadaveric specimens in multiple degrees-of-freedom (DOF) and under combined loading scenarios using the AMTI VIVO, a robotic joint simulator. The anterior portion of the hip capsule was stained with Methylene Blue and virtual extensometers were calculated by Digital Image Correlation (DIC) software for Finite Element Analysis (FEA) model validation. The range of motion (ROM) …

Domestic Violence In Rural & Non-Rural Areas: A Study On The Influence Of Population Density On Arrest Rates In The State Of Florida, Kiara Gonzalez Cruz

Electronic Theses and Dissertations

Domestic violence (DV) is a global issue that can affect anyone regardless of what role they play in a family household. It does not discriminate by education, age, religion, etc. DV includes any type of violence or abuse that occurs within a domestic setting. For the purposes of this study, this content primarily focuses on intimate partner violence (IPV) as the main form of DV and is used interchangeably throughout the text. This study examines the influence of population density on arrest rates for DV and some factors behind the likelihood of arrests in urban and rural areas. The literature …

The Ecology Of Central Florida's Thief Ants (Hymenoptera: Formicidae: Solenopsis), Leo Ohyama

Electronic Theses and Dissertations

Thief ants of the genus Solenopsis are a diverse group of ants that are found in ant communities throughout the world. They have long been purported to practice lestobiosis, an interaction between small and larger-bodied ants, where small ants cryptically tunnel into larger-bodied ant nests within the subterranean environment and steal brood or eggs for consumption. Thief ants are extremely small, measuring 1-2 mm in length and many of the species within this group practice a subterranean life history, where they live the entirety of their lives exclusively belowground. Due to these key characteristics, the ecology and natural history of …

A Comparison Of Bayesian Estimation Techniques In A Multidimensional Two-Parameter Partial Credit Item Response Model, Peiyan Liu

Electronic Theses and Dissertations

Bayesian estimation methods have shown better performance than the traditional Marginal Maximum Likelihood (MML) estimation method for parameter estimation in relatively simple item response models. However, extant literature is lacking on the investigation of Bayesian parameter estimation approaches for a multidimensional two parameter partial credit (M2PPC) model, therefore this simulation study investigated the performance of two Bayesian Markov Chain Monte Carlo (MCMC) algorithms: Gibbs Sampler and Hamiltonian Monte Carlo-No-U-Turn-Sampler (HMC-NUTS) for M2PPC models' parameter estimation. It compared the estimation accuracy and computing speed in different combinations of situations, including prior choices, test lengths, and the relationships between dimensions.

The datasets …

Agronomic And Quality Response Of Hard Red Spring Wheat Genotypes To Management Systems In South Dakota, Jonathan Kleinjan

Electronic Theses and Dissertations

Intensive cereals management techniques such as multiple fungicide applications and in-season split N applications have been used to successfully improve wheat yields in Europe and in some winter wheat production areas of the USA. However, research on the effects of these management practices and their interaction with genotypes is limited in the hard red spring wheat (HRSW) production areas of the USA. The objectives of this study were to: (i) compare management treatments and (ii) quantify any interaction effects between management and genotype on the agronomic characteristics and relevant flour and dough properties of locally-adapted HRSW genotypes. A randomized complete …

A Kinetic Monte Carlo Study Of Mesoscopic Perovskite Solar Cell Performance Behavior, Behzad Bahrami

Electronic Theses and Dissertations

Perovskite solar cells have received considerable attention in recent years due to their low processing cost and high energy conversion efficiency. However, the mechanisms of perovskite solar cell performance are not fully understood. Models based on probabilistic and statistical approaches can be used to simulate, optimize, and predict perovskite solar cell photovoltaic performance, and they can also guide experimental processing and fabrication conditions to achieve higher photovoltaic efficiency. This work developed a 3D model based on the kinetic Monte Carlo (KMC) approach to simulate 3D morphology of perovskite-based solar cells and predict their photovoltaic performance. The model incorporated the physical …

Understanding The Relationship Between Perfectionism And Health: Mediational Effects Drug Use, Sarah Nelsen

Electronic Theses and Dissertations

Past research has provided evidence on the consequences of perfectionism. One particular consequence of perfectionism is that of general health. Research has suggested that perfectionism type influences general mental health. Using the 3-cluster perspective of perfectionism by Slaney, Rice, Mobley, Trippi, & Ashby (2001), the current work investigates the mediating effects of drug use on the relationship between perfectionism clusters and general mental health, in the context of Conservation of Resources Theory (COR; Hobfoll, 1989). Adaptive perfectionists had higher general mental health compared to non-perfectionists and maladaptive perfectionists. However, the three clusters of perfectionism did not differ in drug use …

Impact Of Concussion And Orthopedic Injuries On Physical Activity And Quality Of Life After Sport Retirement, Makenna Hancock

Electronic Theses and Dissertations

CONTEXT: Concussions and orthopedic injuries represent a significant risk related to participation in collegiate athletics. These injuries can create significant long-term impairments and functional limitations which may also decrease former athletes’ quality of life (QoL) and inhibit their ability to engage in physical activity. OBJECTIVE: To investigate QoL and physical activity levels of former collegiate athletes with a history of concussion and orthopedic injury, orthopedic injury only, and healthy controls. DESIGN: Descriptive, experimental study.
SETTING: Daily life as former National Collegiate Athletic Association Division I collegiate athlete.
PARTICIPANTS: Former Division I collegiate athletes competing in football, women’s soccer, baseball, softball, …

Production And Storage Stability Of High Concentrated Micellar Casein And Its Effect On The Functional Properties Of Process Cheese Products, Ahmed Hammam

Electronic Theses and Dissertations

Micellar casein is a high-protein ingredient that can be used in process cheese products (PCP) formulations. PCP is a dairy food prepared by blending dairy ingredients (such as natural cheese, protein concentrates, butter, non-fat dry milk NFDM, whey powder, and permeate) with nondairy ingredients (such as sodium chloride, water, emulsifying salts, color, and flavors) and then heating the mixture with a continuous agitation to produce a homogeneous product with an extended shelf-life. The first objective of this study was to produce a highly concentrated micellar casein (HC-MC) and evaluate its storage stability. Skim milk was pasteurized at 76°C for 16 …

Static Load Bolted Joint Elastic Resilience Testing Methodology, Paul Melino

Electronic Theses and Dissertations

Elastic resilience is the ratio of deformation over force an object experiences when under stress. Knowing the how much the bolt and clamped part deform under load is critical when determining fasteners for a bolted joint. VDI 2230 is the internationally recognized bolt sizing standard and contains the equations used to determine each of the bolted joint component’s resilience as well as values for embedment estimates based on component surface roughness. Embedment is the local plastic deformation due to uneven contact over the contact planes of a bolt-clamped interface (Bolt head to plate, plate to plate, plate to nut, and …

Variability Of E. Coli In Streambed Sediments And Its Implication For Water Quality, Sadia Salam

Electronic Theses and Dissertations

Fecal indicator bacteria (FIB), including E. coli, are the number one cause of water quality impairments in the United States according to the USEPA. FIB are used as a predictor to identify the possible presence of pathogens in waterbodies. E. coli is a useful indicator of gastrointestinal (GI) related illnesses from contact with fresh water. While surface water is routinely monitored for water quality, streambed sediments are rarely considered as a source of FIB to the overlying water column. This study focuses on understanding the variation of E. coli concentrations in streambed sediments and the potential impact of sediment sources …

A Bioinfomatic Analysis Of Luminal And Mucosal Ileal Bacteria Colonizing Nursery Pigs Fed Different Protein Sources, Jamie L. Ortman

Electronic Theses and Dissertations

Weaning is a critical time in a young pig’s life that will greatly impact its adult growth and development. The objective of this research was to evaluate the effects of various protein sources on the bacterial composition within luminal and mucosal populations in simple and complex diets to gain a better understanding of factors influencing gut health. Weaned pigs were fed 1 of 3 simple experimental diets: 1) basic diet containing corn and soybean meal (Negative Control - NEG), 2) basic diet + fishmeal (FM; Positive Control - POS), and 3) basic diet + microbially-enhanced soybean meal (MSBM). Phase I …

Does Medicaid Increase Emergency Room Use: Evidence From Oregon Health Program?, Md Fourkan

Electronic Theses and Dissertations

This thesis paper strives to identify the relationship between Medicaid expansion and Emergency Department use. I use a Monte Carlo simulation for demonstrating the endogeneity problem and a copula model using the Oregon Health Program (OHP) data to show the previous literature has exaggerated the causal relation between Medicaid expansion and Emergency Department use. This paper can be divided into two parts. First, it tries to focus on the under-identification of multiple endogenous variables problem in typical econometrics papers, where researchers correct for a single endogenous variable but intentionally or unintentionally ignore the endogeneity of one or more other independent …

Investigating The Late Woodland Climate Of Old Tampa Bay, Florida, Jaime Rogers

Electronic Theses and Dissertations

Tampa Bay and the broader Central Gulf Coast region of Florida bear evidence of site reduction and population decline during the onset of the Late Woodland period (AD 500-1000). Concomitantly, Weeden Island culture flourished to the north, while climatic instability loomed to the south. It is unclear if the site abandonments in the area between the two are related to social or cultural change, an unstable climate, or a combination thereof. Interdisciplinary research has provided evidence for climate change and sea level regression during the sixth and seventh centuries in Southwest Florida, but these variables have yet to be investigated …

Business In The Estuary, Party In The Sea: Migration Patterns Of Striped Mullet (Mugil Cephalus) Within The Indian River Lagoon Complex, Olivia Myers

Electronic Theses and Dissertations

Commercial and recreational environmental enterprises in the Indian River Lagoon (IRL), Florida supply nearly 10,000 jobs and produce $1.6 billion dollars a year in revenue. These waters contain iconic species of sportfish, including red drum, snook, and sea trout, as well as their lower trophic level prey such as snapper and mullet. Striped mullet (Mugil cephalus) are both commercially valuable as well as an indicator species for overall ecosystem health. From September to December, mullet in the IRL undergo an annual migration from their inshore foraging habitats to oceanic spawning sites. However, their actual migratory pathways remain unknown. To address …

Hydrodynamic Limitations And The Effects Of Living Shoreline Stabilization On Mangrove Recruitment Along Florida Coastlines, Christian Pilato

Electronic Theses and Dissertations

The recruitment success of mangroves is influenced by a variety of factors, including propagule availability, desiccation, herbivory, and hydraulic habitat limitations. Hydrodynamic forces (waves and currents) act as obstacles to mangrove recruitment, restricting the successful colonization of mangrove species. We evaluated the biological and physical limitations to mangrove recruitment through monthly shoreline surveys and lateral pull-tests. Surveys followed mangroves from propagule release through recruitment along the shorelines of De Soto National Memorial (Bradenton, FL), capturing differences in propagule availability and recruitment along natural areas and across differing forms of shoreline stabilization ("living shorelines" and revetments). Propagule densities were highest along …

Non-Hermitian And Space-Time Mode Management, Nicholas Nye

Electronic Theses and Dissertations

In the last few years, optics has witnessed the emergence of two fields namely metasurfaces and parity-time (PT) symmetry. Optical metasurfaces are engineered structures that provide unique responses to electromagnetic waves, absent in natural materials. On the other hand, PT symmetry has emerged from quantum mechanics, when a new class of non-Hermitian Hamiltonian quantum systems was shown to have real eigenvalues. In this work, we demonstrate how PT-symmetric diffractive structures are capable of eliminating diffraction orders in specific directions, while maintaining/enhancing the remaining orders. In the second part of this work, we emphasize on supersymmetry (SUSY) and its applications in …

Analyzing Pre-Inhumation Breakage Ceramics At Lamanai, Belize: A Conjunctive Approach, Ryan Enger

Electronic Theses and Dissertations

During the Terminal Classic period (9th-10th centuries A.D.), the ancient Maya at Lamanai, Belize, began to practice pre-inhumation breakage of ceramics in mortuary contexts. Previously, the custom had been to bury whole vessels with the deceased. This conspicuous shift in behavior suggests important changes in beliefs regarding the role of ceramics in death and interment at a pivotal moment in ancient Maya culture history. Despite this significant change, there has been no published research conducted specifically on these vessels. In fact, there has been no clearly delineated set of characteristics for what qualifies as a pre-inhumation breakage vessel (PBV). This …

Mirrors As Portals: Images Of Mirrors On Ancient Maya Ceramics, Julie Rogers

Electronic Theses and Dissertations

The Maya believed there were multiple worlds in addition to the human world. Portals connected these worlds and allowed active engagement between the Maya and their gods. Without portals and the ability to communicate between the worlds the Maya belief system could not function. Evidence suggests the Maya believed reflective surfaces – mirrors and water surfaces – were portals to spiritual worlds. In this thesis, I examine the portrayal of mirrors as portals in Maya art, focusing on mirrors in scenes painted on ceramics. Combining archaeological, iconographical, and linguistic data I argue that mirrors functioned in service to ritual as …