Digital Commons Network^™

Metakaolin-Based Geopolymer Concrete; Synthesis, Development And Characterization, Heba Fouad

Theses and Dissertations

Geopolymers are rendered as an essential sustainable replacement to the widely used Ordinary Portland Cement (OPC) which causes immense carbon dioxide emissions, hence a detrimental impact on society’s health and the environment. Geopolymers are three-dimensional networks of polymerized tetrahedral silicate and aluminate in the form of Q4(4Al), Q4(3Al) and Q4(2Al) which act as the principal binding phase in concrete. Past research has reported the synthesis of geopolymers from different aluminosilicates precursors, their characterization, and their wide range properties. However, previous studies still have not properly investigated effective range of synthesis ratios for a particular source material, optimum curing regimes, short- …

End-To-End Autonomous Quadcopter Using Reinforcement Learning, Mohamed Marwan Chawa

Theses and Dissertations

This thesis investigates the potential of Reinforcement Learning (RL) for achieving robust and adaptable quadcopter control, focusing on trajectory and attitude stabilization. We compare state-of-the-art RL algorithms, specifically Proximal Policy Optimization (PPO), against traditional Proportional-Integral-Derivative (PID) controllers across three tasks: hovering, slow trajectory following, and fast trajectory following. To enhance realism, we employ a modified PyFlyt simulation environment with a high-fidelity Crazyflie 2.x model, accounting for motor dynamics, noise, wind disturbances, and aerodynamic drag.

The challenge of operating a quadcopter can be divided into two distinct parts: planning a flight path and actually following that path. Our focus is on …

Discharge-To-Water Level Conversion Using Monthly Duration Curves (Dwl-Mdc): Enhancing The Utility Of The Geoglows Ecmwf Hydrological Model, Darlly Judith Rojas Lesmes

Theses and Dissertations

Flood early warning systems are crucial for disaster risk reduction strategies, enabling communities to take timely action against threats. However, the effectiveness of these systems depends on accurate and timely hydrological data, particularly river discharge and water level measurements. Unfortunately, many regions, face significant challenges in obtaining hydrological data, especially discharge data due to outdated rating curves, high equipment costs, and logistical constraints. Water level measurements, by contrast, offer reduced uncertainty and are often more accessible, providing an alternative for hydrological modeling in data-scarce regions. To address these limitations, we developed and validated the Discharge-to-Water Level Conversion Using Monthly Duration …

Impact Of Cascading Optical Processes On Spectroscopic Quantification Of Absorption And Scattering Properties Of Samples, Pathum Dilshan De Silva Wathudura

Theses and Dissertations

Light absorption and scattering are fundamental properties of matter, particularly significant in nanoscale materials. This study explores how cascading optical processes affect the experimental measurement of absorption and scattering intensities, along with scattering depolarization, in samples containing absorbers and scatterers. The experimental UV–vis spectrum results from the combination of absorption and scattering extinction spectra. However, the maximum measurable extinction may be limited by forward scattered light. Light absorption decreases the intensity of scattered light and influences scattering depolarization. While scattering can reduce absorption along the optical path to the detector, sufficient absorption of the scattered light may counterbalance this effect, …

Effects Of Metoprolol And Propranolol Beta-Blockers Mixture On Morphological And Physiological Responses In The American Oyster, Andrew Salinas

Theses and Dissertations

Beta-blockers are extensively used to treat human cardiovascular conditions yet pose significant risks to non-target aquatic organisms. This study aimed to investigate the effects of short-term exposure (one week) to a beta-blocker’s mixture (low-dose: 50 ng/L propranolol and 250 ng/L metoprolol, and high-dose: 250 ng/L propranolol and 650 ng/L metoprolol) in the American oysters. Histopathological assessments revealed structural damage to gills, connective tissues, and digestive glands in both low- and high-dose treatment groups. Additionally, glucose concentration and pH of the extrapallial fluid significantly declined in the high-dose treatment group. Hemocyte density within connective tissues increased proportionally with dosage. The beta-blocker …

Investigating Temperature And Emissivity Separation Techniques Through The Use Of A Spectral Emissivity Database, Mitchell A. Manzardo

Theses and Dissertations

This study evaluates two temperature and emissivity separation techniques using data from an ABB MR304 FTIR and a Telops Mid-Wave Hyper-Cam on carbon-based samples heated by a high-energy laser. The established Linear Spectral Emissivity Constraint (LSEC) and Gray Body Emissivity (GBE) methods, as well as a new Robust Ratio Linear Fitting (RRF) method are assessed for their applicability in controlled lab environments. A spectral emissivity database aids in analyzing method performance. The RRF method shows promise but has limitations, particularly with low-temperature data and complex Hyper-Cam data. Despite these challenges, the RRF method offers potential for further refinement.

An Assessment Of Drinking Water Equity In South Carolina: Access, Affordability, Quality, And Private Well Resources, Catherine Lippert Min

Theses and Dissertations

Universal access to good quality, affordable drinking water is a goal that has not yet been reached in the United States. Recently, national studies have investigated drinking water burdens including lack of access to complete plumbing, unaffordability, and poor quality individually. However, no study has examined all of these drinking water burdens together to identify communities facing multiple burdens. This study addresses this gap by analyzing disparities in access to complete plumbing, affordability of public water sources, and drinking water quality of community water systems in South Carolina and identifying communities that face multiple burdens. This study also provides the …

Housing Buyouts At The Intersection Of Flooding And Toxins: A Case Study Of Cheraw, South Carolina, Victoria Ponds

Theses and Dissertations

As climate change increases extreme weather events, efforts of managed retreat will also increase, particularly through housing buyout programs. The largest scale housing buyout programs are run through the Department of Housing and Urban Development (HUD) and the Federal Emergency Management Agency (FEMA). These buyout programs focus primarily on flood hazards and exclude anthropogenic hazards. This policy is problematic in the modern technological age where compound hazards, including those involving toxin releases, are occurring more frequently. In this thesis, I investigate how disaster policies account for the intersection of these hazards in Community Development Block Grant-Mitigation buyouts in Cheraw, South …

Detection And Analysis Of Solid-Phase Nutrients In Complex Benthic Cyanobacterium Communities, Cassidy Ann Crandell

Theses and Dissertations

Eutrophication is one of the most serious water quality issues affecting aquatic systems in the United States. Densely populated urban areas as well as mining and agriculture are major sources of anthropogenic nutrient loading into lakes and rivers. Excess loading of nutrients like phosphorus (P) into these ecosystems can cause native algal species to be outcompeted by harmful algal bloom (HAB) species. Increases in these HAB events are a growing public health concern as contact with excreted toxins can be harmful for human, aquatic, and land species. Remediation techniques like total maximum daily loads (TMDLs) have been implemented to reduce …

Trust In Governance System (Tgs) In The Hotel Context: Scale Development And Validation, Swechchha Subedi

Theses and Dissertations

The purpose of this study was to conceptualize trust in governance systems (TGS) within the hotel context, develop a scale to measure it, and validate its effects on hotel investment decisions. The study focused on the perspectives of hotel leadership which includes the owners, operators, and investors in the United States. The study employed a mixed-methods approach, exploratory sequential research design. Initially, the governance system within the hotel industry was conceptualized, and trust in governance was defined. The scale development phase involved generating items and dimensions through literature review, expert review, and pilot testing. The final scale included multiple dimensions …

Academic Success In First-Year Engineering Students At Private Higher Education Institutions In Egypt: Key Factors, Wassim Alexan

Theses and Dissertations

This research aimed to identify the key factors contributing to the success of first-year engineering students at private higher education institutions (HEIs) in Egypt. It specifically examined how various independent variables influence the success of these students, measured as the dependent variable. By analyzing these relationships, the study seeks to pinpoint key success factors (KSFs) for first year engineering students in this specific educational context. The research work employed a mixed methods approach, utilizing both quantitative and qualitative research methods. The quantitative analysis involved collecting data through a survey administered to a sample of first year engineering students at private …

Assessing The Effects Of Climate Change On Vulnerability To Poverty: The Case Of Heat Waves And Construction Workers In Egypt, Rachad Bani Samari

Theses and Dissertations

“Doomsday, humanity’s extinction, the end of days”. Apocalyptic adjectives abound to highlight the danger looming over the planet, as the earth is warming up due to global warming and climate change. The picture painted over the canvas has consistently projected a gloomy image of low-income countries and of the poor. As the earth is gently boiling with heat, low-income groups in the Global South are predicted to be most affected. However, most of such warnings and studies focused on sectors directly dependent on suitable weather conditions such as agriculture, and sea tourism. While the climatic phenomena of heat waves may …

Motivations For Habitat Management Of Private Lands In The Southeastern United States: Implications For At-Risk Species, Caleb Michael Blake

Theses and Dissertations

Private lands play a crucial role in protecting at-risk species in the Southeast, and finding ways to increase landowner participation in conservation efforts is essential. I surveyed non-industrial private forest owners in Mississippi to assess how their motivations for land management relates to their willingness to manage for at-risk species. I also assessed if landowners who hunt are more willing to manage for at-risk species. Results showed that landowners are motivated by a sense of stewardship for the land, but there is a lack of awareness about at-risk species. Although the effect size was minimal, there is a significant relationship …

間, Lele Dai

Theses and Dissertations

LeLe Dai makes contingent participatory public interventions using sensory materials such as sound, flickering light, and water. This paper examines their works through the lens of Chinese character Jian (間), meaning “gap/slit/incision,” to investigate the concept of “in-betweenness.”

Nir-Spectroscopy With Data-Driven Application For Inspection And Prediction Of Combined Fouling And Moisture Contamination In Railroad Ballast., Eberechi Orie Ichi

Theses and Dissertations

Ballast contamination is a significant and growing challenge that causes railway track deterioration, poor drainage functionality, and early failure of railroad components. Traditional, human, destructive, field sampling, and most nondestructive evaluation (NDE) inspection methods are ineffective. They are plagued by drawbacks, such as inefficiency, subjective inspection outcome, alteration of existing structures, undermining the stability of the railroad substructure, traffic disruptions, and safety concerns, or providing limited information about the condition of the ballast. Therefore, a reliable noncontact technique is needed to evaluate, characterize, monitor, and predict the presence of contamination in railroad ballast. The conventional contamination indices only account for …

Exploration Of Sustainable Attitudes And Behaviors And The Role Of Planned Behavior Amongst The Auc Community, Natalie Tamer Khairy

Theses and Dissertations

This thesis explores the use of a new Framework that was developed by combining both the Theory of Planned Behavior (TPB) and Knowledge, Attitudes, and Practices (KAP) theory to study the sustainability behaviors of students, faculty, and staff at the American University in Cairo (AUC). The research aims to provide insights into the factors influencing sustainable behaviors and how these factors differ across the three groups. The study used a combination of questions from the sustainability awareness questionnaire (SAQ) and Sulitest that was customized to the cultural context of the target group. The survey was administered to a sample of …

Green Fame On Tiktok Analyzing Digital Persuasion Appeals On Climate Change Discourse Among The Public And Youth., Sherry Ayad

Theses and Dissertations

In a constantly changing media ecosystem, TikTok is gaining prominence and attention, particularly among youth and Gen Z. The platform’s unique affordances are recently being utilized by young voices to promote self-expression and social activism. Consequently, TikTok’s changing nature is giving space for serious social and political issues impacting the future of young generations on topics such as climate change. By analyzing the top N=400 TikTok videos from the 27th Conference of the Parties (COP27) to the 28th Conference of the Parties (COP28), this study contributes to rare knowledge of utilizing TikTok’s affordances in scientific and political topics such as …

The Implications Of Covid-19 Pandemic On Indoor Environments: Balancing Environmental Considerations And Wellbeing In Higher Educational Facilities, Farah Shoukry

Theses and Dissertations

In this dissertation, the evolving problems concerning Indoor Air Quality (IAQ), and Indoor Environmental Quality (IEQ) in learning environments are examined. The topic is inspired by the COVID-19 pandemic and aspires to document the lessons learned via a vast set of investigations for enhanced IAQ management and control. Specifically, within educational buildings, the challenge remains to better inform the design and management of educational facilities to foster healthier and more sustainable learning environments. There are emerging research topics related to IAQ post the COVID-19 – including but not limited to: architectural design considerations of university classrooms, increase in carbon footprint …

Barley As A Human Companion Species - Exploring The Relationship Between Barley And North Atlantic Peoples: 4000 Bc – Ad 1200, Chloe Combs

Theses and Dissertations

Barley (Hordeum vulgare) is an ancient cereal crop originating in the Fertile Crescent approximately 12,000 years ago and is presently one of the most important cereal crops globally. Barley has a long and complex history. This thesis aims to explore one dimension of this history through the lens of human companion species using archaeobotanical data collected from the islands of the North Atlantic from the Neolithic (4,000 BC) to the Norse period (AD 1200).

Range-Wide Analysis Of The Genetic Diversity And Genetic Structure Of The Spotted Turtle (Clemmys Guttata), Madison S. Whitehurst

Theses and Dissertations

Understanding the spatial distribution of genetic diversity and structure in endangered species is vital for effective conservation management. This research discusses the results of an initial analysis of the genetic structure and variation of the spotted turtle (Clemmys guttata), a species of conservation interest. The study sampled 913 individuals from 78 unique locales across 16 states in the eastern portion of the species' range. Utilizing ddRADSeq, a de novo genome assembly was developed to identify nearly 20,000 potential loci. A total of 926 were selected for this analysis. Results revealed no spatial clustering of genetic diversity or structure, …

“You Are Not Obligated To Complete The Work, But Neither Are You Free To Desist From It.” Richmond Jews In Social Activism Post Civil Rights, Tracy S. Herman

Theses and Dissertations

For centuries, the Jewish people have faced expulsions, pogroms, massacres, and Propaganda. that runs so deep it would be like staring into an abyss. This oppression has motivated Jewish activists worldwide to fight back not only on behalf of the Jewish community but for many areas of perceived need. Jewish involvement in social activism in the U.S. has been particularly recognized by scholars of the labor and Civil Rights movements. This thesis is based on eighteen oral history interviews focused on social activism in Richmond, Virginia since the Civil Rights era. The author conducted these interviews in 2021, 2023, and …

Effects Of Flooding And Plant Community Arrangement On Freshwater Wetland Greenhouse Gas Emissions And Plant Growth, Walker A. Trainum

Theses and Dissertations

Climate change threatens the status quo of tidal freshwater wetlands by altering their hydrology and species makeup. Increases in water level within freshwater wetlands are well studied, but with the inclusion of saltwater intrusion; while common for some tidal wetlands affected by sea level rise, it is not universal. For wetlands that will experience flooding apart from increases in salinity, adequate study is lacking. For these wetlands, the effect of increasing water level is largely unknown. Thus, the aim of this study was to use an outdoor mesocosm experiment to isolate effects of flooding and communities of differing species makeups …

Western Pacific K-12 Educators’ Adoption Of Digital Game-Based Learning, Lorraine Raqueño Catienza

Theses and Dissertations

Western Pacific educational institutions are investing heavily in technology in classrooms to meet the needs of K-12 students. Measuring the effective use of digital technologies in the learning environment has become a routine part of monitoring and evaluating classroom instruction. One area of technology integration that has seen tremendous growth is digital game-based learning (DGBL). The researcher is interested in examining K-12 western Pacific teachers’ willingness to adopt DGBL through a modified Technology Acceptance Model. This study aims to examine the extent to which teachers’ perceived usefulness, perceived ease of use, and technology self-efficacy effects attitude toward adopting DGBL methods. …

Characterizing Stress Granule Regulation By Pas Kinase, Ataxin-2 And Ptc6 And Investigating The Lifespan Of Covid-19 Virus On Currency, Colleen R. Newey

Theses and Dissertations

The protein Ataxin-2 is a known positive regulator of stress granules in humans, mice and yeast (known as yeast PBP1). Due to the role that stress granules play in diseases including Amyotrophic Lateral Sclerosis (ALS) and cancer, this thesis investigates the role of Ataxin-2 and its protein binding partners in stress granule development and its effects on various metabolic phenotypes of the cell. PAS kinase is a sensory protein kinase, conserved from yeast to man, which regulates respiration and lipid biosynthesis. Our lab discovered that PAS kinase phosphorylates and activates Ataxin-2 in yeast, and that PAS kinase overexpression enhances localization …

Investigation On Mechanical, Tribological And Corrosion Resistance Properties Of Nano Sized Tio2/ Corrosion Resistance Properties Of Nano Sized Tio2/ B4c / Graphene Reinforced Aa 7075 Surface Composites B4c / Graphene Reinforced Aa 7075 Surface Composites Fabricated By Frictional Stir Processing Fabricated By Frictional Stir Processing, Majed Mohammed Hotami

Theses and Dissertations

Today, significant research efforts in the field of manufacturing engineering are focused on developing new lightweight, fuel-efficient and high-performance materials. The evolution of composite materials and related technologies has brought great advantages to material development throughout history. Composites are versatile materials with unique mechanical and physical properties tailored to specific application needs. Composites allow engineers to make design choices that traditional monolithic (unreinforced) materials cannot offer. Particle Reinforced Metal Matrix Composites (MMCs) offer a variety of advantages, including increased stiffness, improved fatigue resistance, increased wear resistance, and a low coefficient of thermal expansion. Aluminum MMC (AMMC) material systems outperform monolithic …

Effects Of Ai Voice Assistants’ Messages On Pro-Environmnetal Consumer Behavior: Message Content And Voice Attributes, Somang Min

Theses and Dissertations

The hospitality and tourism industry has increasingly prioritized environmental concerns, driving the adoption of green practices and communication strategies. This dissertation investigates the role of AI voice assistants in hotel rooms in promoting pro-environmental behavior, recognizing the importance of fostering environmental mindfulness through technology and behavioral interventions. This research explores the influence of voice attributes and message content on consumers' pro-environmental behavior when conveyed through AI voice assistants. It specifically focuses on the marketing cue of Kindchenschema cuteness by examining how a baby-like voice in AI voice assistants may enhance pro-environmental communication, a topic rarely addressed in the hospitality and …

Small Area Estimation Of County-Level Forest Attributes Using Forest Inventory Data And Remotely Sensed Auxiliary Information, Okikiola Michael Alegbeleye

Theses and Dissertations

The Forest Inventory and Analysis (FIA) program of the United States Department of Agriculture Forest Service collects forest inventory data that provide estimates with reasonable accuracy at the national scale. However, for smaller domains, these estimates are often not as accurate due to the small sample size. Small area estimation improves the accuracy of the estimates at smaller domains by relying on auxiliary information. This study compared direct (FIA estimates), indirect (multiple linear regression), and composite estimators (Fay-Herriot) using auxiliary information derived from Landsat and Global Ecosystem Dynamics Investigation (GEDI) to obtain county-level estimates of forest attributes namely total and …

The Effect Of An Elephant Conservation Education Program On The Knowledge Base Of Children In Thailand, Angela Larios

Theses and Dissertations

Habitat fragmentation and human-elephant conflict (HEC) are two factors that have caused harm to both Asian elephants and humans in Thailand. Think Elephants International (TEI) is a non-profit organization whose goal is to educate children on these issues to encourage more interest in and knowledge about elephant conservation in the youth of Thailand. TEI has developed a systematic education initiative and established a method for assessing the program’s efficacy using a pre- and post-survey. The current study analyzes student responses from one open-ended question from this survey collected both before and after the students participated in the TEI program. This …

Understanding The Distribution And Abundance Of Asclepias Prostrata In South Texas, Elizabeth Ann Gonzalez

Theses and Dissertations

Asclepias prostrata, commonly referred to as prostrate milkweed, is a rare South Texas native plant species. In February of 2023, A. prostrata was listed as a federally endangered species by the U.S. Fish and Wildlife Service. Due to the limited available observations and literature for A. prostrata, this study was completed to bring new information that could be utilized for future restorative efforts. This study includes multiple field observations of the plant’s morphology, plant-insect interactions, extraction and transplanting of the species, and a seed viability study. Results indicate that although A. prostrata has many pressures that limit its …

Evaluation Of Green Roof Technology In Egypt, Hend Abada

Theses and Dissertations

A green roof is a well-known technology worldwide that provides many social, economic, and environmental benefits. In Egypt, green roofs are still a new construction practice where most stakeholders lack business and technical expertise within this emerging industry. This research is concerned with assessing this emerging technology within its contemporary context, Egypt, and testing its feasibility within the physical condition of the Egyptian buildings and the social and economic conditions of the Egyptians. This study starts by presenting intensive information about green roof technology and reviewing the literature on green roofs within the Egyptian context. A grounded methodology is used …