Digital Commons Network^™

Thermal Desorption-Pyrolysis Gas Chromatography-Mass Spectrometry Method Development For The Determination Of Wood Preservatives, Nafisa Bala

Theses and Dissertations

A thermal desorption-pyrolysis gas chromatography with mass spectrometric detection (TD-Pyr-GC-MS) method was developed, enabling a comprehensive analysis of preservatives as well as native wood constituents in treated wood. The developed method is based on thermal desorption, i.e., extraction of wood preservatives, followed by pyrolysis to investigate changes in the occurrence of characteristic wood building blocks (e.g., guaiacol derivatives). We implemented a combined MS data acquisition (i.e., SITI) consisting of selected ion monitoring (SIM) and total ion current (TIC), allowing for low limits of detection of preservatives in SIM mode and TIC detection of any evolving species. The matrix detection limits …

Identity Formation Through The Lived Experiences Of Immigrant Muslim High School Students, Badera Muhanna

Theses and Dissertations

The growing number of Muslim students enrolled in U.S. public schools necessitates a more comprehensive understanding of their unique experiences within their educational environments. This phenomenological qualitative study investigated Muslim students' perceptions of their lived experiences in a high school in the Northern Great Plains of the United States. Six Muslim students in their junior and senior years were selected to participate in semi-structured interviews. Through the lens of Bronfenbrenner’s ecological systems theory, this study aimed to deepen understanding of how Muslim students develop their sense of identity and the factors that contribute to this development. The findings revealed that …

Exploratory Study Of Relationships Between Law Students' Well-Being, Academic Success, And Perceptions Of Passing The Bar Exam And Admission, Pamela Shea

Theses and Dissertations

This study explores the experiences of law students that impact their perception of being prepared for the Bar Exam and Bar admission. Analyzing the stressors law students face during law school reveals the essential need to incorporate the eight dimensions of well-being into curricular, co-curricular, and extra-curricular activities for students to flourish as they prepare for post-graduation success. Using the data from the 2021 Survey of Law Student Well-Being, which surveyed 5,865 law students from thirty-nine ABA-accredited law schools, a three-factor model was created to group students’ concerns into academic and health concerns, social and environmental concerns, and well-being behavioral …

Integration Of Fluorescence Imaging And Advanced Analytical Techniques For Reliable Contamination Detection, Mahsa Aliee

Theses and Dissertations

Effective surface contamination detection in food processing and healthcare environments is hindered by the limitations of visual inspection and ATP bioluminescence testing, both of which struggle to identify thin, transparent, or spatially irregular organic residues. These constraints contribute to inconsistent hygiene verification and create a need for objective, scalable, and real-time detection methods capable of operating under variable environmental conditions.

This dissertation develops an integrated framework that combines UV-induced fluorescence imaging with advanced analytical techniques to improve contamination detection reliability. A UV/UVC fluorescence imaging system was engineered with synchronized pulsed excitation (275 nm, 365 nm, 405 nm), adaptive exposure control, …

The Role Of Attitude Ambivalence In Extending The Theory Of Planned Behavior: A Mixed-Methods Study Of Factors Predicting Influenza Vaccine Uptake Intentions Among Active-Duty Military Parents For Themselves And Their Children, Walter Eugene Carroll

Theses and Dissertations

This dissertation is a mixed-methods study examining how U.S. military parents form intentions to vaccinate themselves and their children against influenza. The study applies the Theory of Planned Behavior (TPB) and the construct of ambivalence tounderstand how attitudes, social norms, and perceived behavioral control influence vaccination decisions within the unique institutional and cultural environment of military life. Quantitative data were collected from 341 military parents through an online survey distributed across more than 50 military-affiliated Facebook groups. Regression models tested TPB constructs, flu knowledge, and social media use as predictors of vaccination intention and ambivalence. Results showed that flu shot …

Examining The Utility Of Haptic Feedback To Improve Pilot Situational Awareness & Performance: A Psychophysiological Approach, Jessica Van Bree

Theses and Dissertations

Pilot situational awareness (SA) has been deemed to be a critical component of flight efficacy, efficiency, and overall mission success. Studies have shown that several incidents and accidents have been the result of level-one SA errors, meaning that members of the flight crew have failed to accurately perceive the elements in their environments. As such, several strategies have been investigated to improve pilot SA. One potential avenue of research is the addition of haptics in to the flight deck. In some studies, the implementation of haptics have shown to improve piloting tasks, pilot safety, and aircraft control. The current study …

Optimizing Virtual Reality User Experience With Balanced Integration Of Quality Attributes, Ananth Ramaseri

Theses and Dissertations

This dissertation presents a real-time adaptive framework for mitigating cybersickness and enhancing user experience in virtual reality (VR) environments by dynamically adjusting key visual rendering parameters in response to users’ head movements. Conventional VR systems typically rely on fixed or manually configured settings that do not account for individual motion patterns or varying susceptibility to discomfort, leading to suboptimal usability and degraded immersion. In response, this work integrates software architecture tactics with data-driven machine learning models to proactively manage cybersickness while preserving rendering performance.

The proposed system employs a client–server architecture based on the Model-View-Controller (MVC) pattern. We conducted a …

Pfos And Lung Injury: A Review Of Human And Experimental Evidence, Farzana Hakim

Theses and Dissertations

Human epidemiological research has shown the adverse health consequences of long-term accumulation of per- and polyfluoroalkyl substances (PFAS) in human tissue. Specifically, this review will examine the relationship between PFAS exposure, impaired immune system functioning, and an elevated risk of respiratory disease using both human and experimental data. Research on human populations indicates that children exposed to PFAS have lower levels of antibodies to vaccines; those children prenatally exposed to PFAS are more susceptible to upper respiratory infections; and that adult humans have a higher incidence of chronic obstructive pulmonary disease (COPD). Additionally, experimental studies demonstrate that PFOS and PFOA …

Influence Of Peer-Led Team Learning In Students’ Chemistry Self-Efficacy, And Academic Achievement In General Chemistry Courses, Hector Leal

Theses and Dissertations

One of the most perplexing issues facing peer cooperative learning is dealing with student motivation and goal orientation. Sometimes the students who could most benefit from the positive effects of peer learning are the ones least likely to participate due to fear of exposing their academic weaknesses to others or even to themselves (Arendale, 2020). Exploring the complexity of student motivation is being carefully studied amongst elementary and secondary education student populations. However, this important construct is often ignored in the study of postsecondary education in general, and the provision of learning assistance, particularly at the college level. My purpose …

Exploring Factors That Contribute To The Success Of Latina Superintendents In South Texas, Juanita D. Ybarra-Rodriguez

Theses and Dissertations

The COVID 19 pandemic brought forth many new challenges to the K-12 public schools. Superintendent turnover rates reached concerning levels in Texas and nationwide. This study explored the relationships between Latina superintendent’s success and the superintendents’ experiences with the school board, the community, their own health and safety and experiences related to maintaining superintendents’ role. Success is defined as a participant who acquired the superintendent role and maintained it for at least three years. Participants in this study were selected from Hispanic female superintendents within the Region One Education Service Center (ESC) in South Texas who had acquired and remained …

A Qualitative Case Study: Exploring Distributed Leadership In Instructional Leadership Teams, Martha Reyna Perez

Theses and Dissertations

This dissertation explored the role of distributed leadership within Instructional Leadership Teams (ILTs) at the elementary level, using Beckhard’s (1972) GRPI framework— Goals, Roles, Processes, and Interpersonal Relationships—as a lens. Conducted as a qualitative case study at Rio Vista Elementary in Lone Star Independent School District, the research examined how ILTs functioned in the context of post-pandemic education, focusing on collaboration between administrators and teacher leaders. Guided by Spillane’s (2006) distributed leadership theory, the study addressed three questions: the lived experiences of ILT members, shifts in teacher leadership and organizational conditions, and perceived impacts on student outcomes. Findings showed that …

A Qualitative Case Study: Exploring Distributed Leadership In Instructional Leadership Teams, Martha Reyna Perez

Theses and Dissertations

This dissertation explored the role of distributed leadership within Instructional Leadership Teams (ILTs) at the elementary level, using Beckhard’s (1972) GRPI framework— Goals, Roles, Processes, and Interpersonal Relationships—as a lens. Conducted as a qualitative case study at Rio Vista Elementary in Lone Star Independent School District, the research examined how ILTs functioned in the context of post-pandemic education, focusing on collaboration between administrators and teacher leaders. Guided by Spillane’s (2006) distributed leadership theory, the study addressed three questions: the lived experiences of ILT members, shifts in teacher leadership and organizational conditions, and perceived impacts on student outcomes. Findings showed that …

Hispanic Academic Leadership In The Health And Human Services, Gabriela Elizabeth Rangel

Theses and Dissertations

In the United States, there are 63.7 million Hispanics (U.S. Census Bureau, 2023), making them the largest racial or ethnic minority in the country. National data from 2019 indicates that only 6% of tenured faculty in the U.S. were Hispanic, highlighting a significant underrepresentation of leaders in academia (NCES, 2024). This study employed a phenomenological approach with purposeful sampling, utilizing semi-structured interviews with ten participants who had leadership experience in academia within Health and Human Services (H&HS). The interviews served to explore various aspects, such as what were their aspirations to become leaders, their perceptions of the characteristics and qualities …

Educators’ Perceptions Of Mental Health Services For Middle School Students In A South Texas District, Norma Araceli Cabrera

Theses and Dissertations

The purpose of this phenomenological qualitative study is to examine teachers' and administrators' perceptions of school-based mental health services in one school district in South Texas. Within-case sampling was utilized to select the participants. The study examines educators' perceptions of the availability and effectiveness of mental health services for middle school students. Middle school is a period of intense social development, during which students strive to navigate peer relationships. Middle school children, aged 12-14, also undergo emotional development as they manage intense emotions, develop self-awareness, and learn to cope with stressors related to school, friends, and self-identity. Studies found that …

The Lived Experiences Of School Counselors, Job Burnout, And The Blurred Lines Of The Profession, Cecilia Angelica Gomez

Theses and Dissertations

This phenomenological qualitative study explores the lived experiences of school counselors during and after the COVID-19 pandemic, focusing on job burnout, role ambiguity, and the blurred lines of the profession. Through semi-structured interviews with practicing school counselors, the study identifies common themes including role overload, manifestations of burnout, coping and resilience strategies, and the impact of administrative support. Findings highlight the systemic factors contributing to counselor stress and the importance of self-care, peer collaboration, and role clarity for counselor well-being and student outcomes.

Cyberbullying And Mental Health Issues Among University Students, Brandi N. Cruz

Theses and Dissertations

According to the CDC (2024), bullying can lead to social and emotional distress, self-harm, and death. Bullying can also increase the risk for depression, anxiety, and poor academic achievement. The increased use of social media and the rise in cyberbullying (CB) and related mental health concerns among emerging adults is highly disconcerting, especially given their propensity for mental health problems. The purpose of this study is to increase the understanding of young university students’ perceptions about CB victimization and whether CB affects their mental health. A cross-sectional research design was used to conduct the study. In this study the number …

A Study Of Preferred Modality Of Education And Perceptions Of Academic Success Of Post 9/11 Student Veterans, Jason R. Wakefield

Theses and Dissertations

Veterans are pursuing higher education at increasing rates due to the benefits available upon separation or retirement from military service. Many choose online programs for flexibility, while others prefer traditional, in-person instruction. Regardless of modality, student veterans often face significant challenges completing their degrees. “When student veterans first enter college, they must transition to the overwhelming, independent, and fast-paced lifestyle of a college student” (Semer & Harmening, 2015). While online learning may contribute to these difficulties, other factors also hinder success.

Colleges and universities continue to explore why student veterans struggle to complete their programs, yet underlying issues may distort …

Collective Agency And Community Resilience Among Farmworkers In The Lower Rio Grande Valley, Angel Velazquez

Theses and Dissertations

This research assesses how farmworkers in the Lower Rio Grande Valley of Texas use everyday practices to build resilience and adapt to changes in their lives. I apply two interconnected theories, White’s (2017, 2019) framework of collective agency and community resilience and Castro and Sen’s (2022) framework of everyday adaptation actions, to study these practices. I conducted 19 semi-structured interviews with Latino farmworkers and professionals who work with local farmworker organizations in the Rio Grande Valley (RGV) of Texas. Interview transcripts were analyzed to determine if and how Latino farmworkers in the RGV can work towards community resilience and implement …

Determination Of An Effective Natural Boxelder Bug (Boisea Trivittata) Repellent, Reyna Chavez

Theses and Dissertations

This study investigates the use of ecofriendly repellant alternatives to pest management to control boxelder bugs (Boisea trivittata). This bug gathers by the thousands on warm surfaces of exterior suburban homes during early fall and late spring. I determined bug repellency to turmeric oil (Curcuma longa), catnip (Nepeta cataria), citronella (Cymbopogon nardus), and lavender (Lavandula angustifolia). The treatments consisted of essential oils containing 20% methanol. All treatments demonstrated repellency of Boxelder bugs. Citronella was the most effective and had the highest level of repellency range of 90-99%. Catnip was the least effective with a repellency range of 63-82%.

Burdened By Conviction: The Pressures Within, Dulce M. Perez

Theses and Dissertations

This thesis investigates how religious and political systems, particularly Catholic influences in the Rio Grande Valley, limit and silence women. By employing historical and alternative photographic techniques such as cyanotype, gum bichromate, and photo transfer, I express how these systems control and shape women’s lives. Combined, the materials serve as a metaphor for the oppression and damage which power can inflict. In these works, fabric represents the potential for manipulation of the human mind; the red thread stitched through cloth and paper symbolizes control; and fragmented images are a reference to the collapse of humanity. Throughout this exploration, I reflect …

Clustering 24-Hour Ambulatory Blood Pressure Time Series With Dynamic Time Warping And Time Warp Edit Distance, John Knight

Theses and Dissertations

Ambulatory blood pressure monitoring (ABPM) captures dynamic circadian changes in blood pressure (BP) that are not reflected in static clinic readings. This study applied time-series clustering with two elastic distance measures—Dynamic Time Warping (DTW) and Time Warp Edit Distance (TWED)—to identify distinct phenotypes in 2,155 24-hour ABPM time series from participants in the Maracaibo Aging Study. DTW and TWED both yielded three clusters corresponding to non-dipping, moderate-dipping, and strong-dipping patterns. The non-dipping group showed elevated nighttime BP, associated with greater cardiovascular and cognitive risk, while the strong-dipping group was associated with higher education and younger age in baseline clinic measurements. …

A Picture Tells A Thousand Words—, But Ecg Signals Have More To Say, Ashley N. Gomez

Theses and Dissertations

With the increasing adoption of deep learning classification models in the medical domain, a critical challenge remains: achieving high predictive accuracy while maintaining clinical Inter-pretability. This study examines how model architecture, dataset origin, and the use of full versus subset data affect both classification performance and Interpretability in Electrocardiogram (ECG) signal analysis. ResNet18 is evaluated using an open-source ECG Image Dataset, thus a custom dataset derived from digitized ECG images. Post-hoc explainability methods, such as Integrated Gradients, are applied to determine which time steps have the most significant influence on model decisions. The findings demonstrate that model architecture and dataset …

Cyberbullying Victimization And Suicide Behavior: The Roles Of Social Anxiety And Body-Related Comparison Among Young Latina Adults, Monica Elena Ochoa

Theses and Dissertations

Suicide behavior rates have increased over the years in the United States among Latinas and adolescents/young adults. Previous research has identified relationships between various body-related concerns, (e.g., body dissatisfaction, appearance comparison, and body shame) cyberbullying, social anxiety, and suicidal ideation, yet minimal research has examined the relationship of these factors and how they interrelate to explain suicide risk in Latina young adults. This study investigated whether body dissatisfaction, appearance comparison, and body shame had indirect effects on suicide behaviors through the interaction of cyberbullying victimization in 194 Latina college students. The results of this study found that cyberbullying victimization mediated …

Interactive Effects Of Nutrient Loading And Hyposalinityon The Physiological Responses Of The Red Macroalga Gracilaria Tikvahiae, Donavuan Vincent Salazar

Theses and Dissertations

Coastal macroalgae face anthropogenic stressors such as nutrient enrichment from nitrogen fertilizers and reduced salinity linked to flooding. The physiological impacts of these combined stressors remain unclear. This study examined interactive effects of nitrogen loading and hyposalinity on Gracilaria tikvahiae through a 9‑day laboratory experiment. Samples experienced declining salinity (35–0 ppt) with nitrate or ammonia enrichment (120 µmol/L). Measurements included primary production, respiration, biomass, nitrate uptake, and chlorophyll‑a. Hyposalinity significantly reduced physiological performance, with gross primary production declining over 100%, chlorophyll‑a content 25–45% lower, biomass loss, and reduced nitrogen uptake. Nitrogen enrichment failed to mitigate the adverse impacts under hyposaline …

Bacillus Subtilis: A Bacterium That Can Potentially Degrade Low-Density Polyethylene (Ldpe) And Polyethylene Terephthalate (Pet), Migdalia Flores

Theses and Dissertations

The widespread application and disposal of plastics, such as low-density polyethylene (LDPE) and polyethylene terephthalate (PET), have raised significant environmental health concerns. Because of each plastic’s stability and durability, these plastics exhibit limited natural degradation in the environment. Recently, the environmentally friendly biodegradation of plastics by living microorganisms has attracted more attention, as they can assist in the natural degradation process. In this study, the bacterial strain Bacillus subtilis ATCC6051 was used to degrade LDPE and PET for 60 days. To measure the degradation of low-density (LDPE) and polyethylene terephthalate (PET), the dry weight was taken, and physical characteristics were …

Development And Testing Of A Prototype Erbium-Doped Lithium Tantalate Based Sensor For Infrastructure Crack Detection And Measurement, Alejandro Barrera

Theses and Dissertations

Ensuring the safety and longevity of infrastructure is crucial to safeguarding communities and preserving economic stability. In this study, the development of a novel sensor for detecting and characterizing cracks in infrastructure, particularly suited for deployment on Unmanned Aerial Vehicles (UAVs), is presented. The device utilizes a laser (operating at 980 nm) for excitation of erbium-doped lithium tantalate nanoparticles that emit 1550 nm wavelength, which stimulates a photodiode for data collection. The data was utilized to collect, process, and reconstruct topological information. The synthesized lithium tantalate nanoparticle samples vary in erbium doping percentages of 0.5%, 3%, and 10%. Experimental evaluation …

Applicability Of Cementochronology To Estimate Season-Of-Death In Humans: Insights From Modern Documented Collections, Olga Ibarra-Sanchez

Theses and Dissertations

Dental cementum is characterized by lifelong deposition of alternating opaque annuli in fall/winter and translucent bands in spring/summer. This study aims to test the applicability of cementochronology to estimate season-of-death, by observing the properties of the last layer, with direct implications for forensic anthropology and bioarchaeology. The sample includes canine teeth from 146 adults (84 males, 62 females), age-at-death ranging from 20-97 years (mean=61.7 years, SD=18.6 years), from two contemporary skeletal collections. Of these individuals, 78 (53.4%) died in spring/summer and 68 (46.6%) died in fall/winter. Overall accuracy was low at 64.4% (94/146). Accuracy was higher for spring/summer deaths 100.0% …

Feature Extraction From Railroad Bearing Onboard Vibration Sensors Using Machine Learning Models, Diego Cantu

Theses and Dissertations

The University Transportation Center for Railway Safety (UTCRS) has developed an algorithm capable of identifying defective railroad bearings, determining damaged component(s) within, and quantifying severity of the defects. The defect-detection algorithm requires the operating speed as an input, which is not readily available in field operation of onboard sensors. Therefore, onboard sensors deployed in rail revenue service must rely on Global Positioning Systems (GPS) to obtain speed, which can be power-intensive and susceptible to signal interference. This study covers the development of a vibration-based model that extracts operating speed from wireless sensor data to enable fully autonomous onboard diagnostics. Signal …

An Evaluation Of Noncontingent Reinforcement And Additional Treatment Components In The Treatment Of Stereotypic Behavior, Stephanie Nicole Brand

Theses and Dissertations

Individuals with autism often engage in stereotypic behavior that competes with learning and social skills. Behavior analytic treatment may be implemented to reduce stereotypy. Noncontingent reinforcement (NCR) is one treatment that is often effective to reduce stereotypy. However, literature suggests that the use of NCR is contraindicated in some circumstances, as it may compete with the acquisition of new skills or may increase subsequent persistence of stereotypy. This research was designed to expand our knowledge of potential limitations of NCR when combined with other treatments. Study one examined persistence of stereotypy following treatment with NCR with and without response blocking. …

Benthic Infaunal Responses To Shoreline Restoration, Jessica Lauren Cline

Theses and Dissertations

In the age of increasing urban coastal sprawl, natural shorelines are being replaced by hard armoring structures, which result in the loss of valuable ecosystem services. Hybrid living shorelines, areas that include limited and less intensive armoring strategies paired with the integration of plants and other natural materials, present an opportunity to marry the need for more aggressive stabilization with the continued preservation of ecosystem functions and biological communities. This project uses benthic infauna to evaluate the success of a living shoreline installation in Palm Bay, Florida. The deployment features experimental treatments of breakwaters and red mangroves to explore how …