AUETD (Auburn University)
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Characterizing Strength Loss in High Plasticity Clays Along Alabama Highways
No full textStrength loss in high plasticity clay soils is a common occurrence along roadways in western and central Alabama and has considerable impact on pavement distress and slope failures. Approximately $16 million was spent to repair slope failures in western and central Alabama between 2005 and 2015 with many of these failures occurring in areas with high plasticity Prairie clays. Selecting strengths for these soils to use in slope stability analyses is often a key source of uncertainty and the selected strengths must account for effects of loading conditions and any potential changes in strength over time. For high plasticity clay, such as the Prairie clays in Alabama, repeated cycles of wetting and drying can reduce the available drained shear strength to the fully softened condition before large movements occur. This reduction in strength can lead to failure without any change in loading and accounting for this potential strength loss when analyzing the stability of these slopes is critical to obtain accurate results. The torsional ring shear test can measure both the fully softened strength (used for first time failures) and the residual strength (used for ongoing or reactivated failures) of high plasticity clays. For this study, clay samples were collected at six landslide sites around Alabama. Samples were tested to determine the index properties, electrical resistivity, mineralogy, and fully softened and residual strengths. The results from these tests were compared with existing correlations to determine which correlations were the most appropriate for use in Alabama. For two of the sites, slope stability analyses were performed to compare with observed performance at the site. The results show that the strength envelopes from ring shear testing are consistent with the observations at both sites, although nonlinear envelopes are needed. Recommendations are provided for correlations that can be used to estimate strengths when ring shear testing is not available and for cases where existing correlations do not provide good estimates
Guideline of Outdoor Exercise Equipment for Elderly and Elderly with Disabilities
No full textAging causes a number of problems that can lead to physical health issues such as musculoskeletal problems in older adults and older adults with disabilities. This thesis examines the benefits of outdoor exercise for older adults and older adults with disabilities. The guide is selective, allowing designers to choose the parts of the body that need to be exercised and then choose different users such as older people or older disabled people. With this guide, designers will learn what to avoid and what to consider, laws and regulations, and some dimensions. With this tool, designers can create more comfortable and safe outdoor exercise equipment for seniors and older adults with disabilities
The Effects of Self-Efficacy on ROTC College Student
No full textThe purpose of this mixed methods study was to better understand the relationship between various motivational constructs and success among ROTC students at a southeastern public university. The study assessed the ability to predict cadet success using known measures of performance, such as student GPA and Physical Fitness scores, and the motivational constructs of self-efficacy and Achievement Goal Orientation when compared to the ranking done by ROTC detachment leadership. Though motivational theory and constructs are often looked at in educational settings, there is little research into their effect in military training settings and even less when looked at within the context of ROTC detachments on a university campus. Ordinal Linear Regression was used to determine the relative impact any of the independent variables had on final cadet rankings. An in-person survey method was used to gather demographic information and information related to ROTC Self-Efficacy and AGQ-R (Elliot & Murayama, 2008).The eight item ROTC Self-Efficacy scale (RSE) was adapted from the General Self-Efficacy Scale by Chen et al. (2001), and displayed high reliability, α = .831. The sample was drawn from the total cadets of the Air Force ROTC detachment at the university. Of the 129 cadets, 118 cadets responded, and 105 adequately completed their surveys and had all GPA and physical fitness information available for analysis. Overall, GPA and the Performance Approach and Avoidance constructs of Achievement Goal Orientation were shown to predict the final ranking.
In addition to the quantitative analysis 6 cadets were interviewed regarding their experiences within ROTC to determine if they felt self-efficacy was important and that theirs had grown since entering the program. The responses of the cadets all indicated that they felt self-efficacy was important and that they had experienced personal growth since entering the program. Additionally, the theme of relationships and its importance to the growth of the cadets in many areas emerged as an important finding from the interviews
Factors impacting gobbling chronology and activity of male wild turkeys (Meleagris gallopavo) in Alabama
No full textEastern wild turkeys (Meleagris gallopavo silvestris) are the second most pursued game species in the United States and hold significant cultural and economic value across the Southeast. Recent declines have raised concerns regarding population sustainability. Consequently, many Southeastern states (e.g., Alabama) have adjusted season frameworks through delayed seasons and reduced bag limits in an effort to reverse these trends. The potential impacts to wild turkey populations and hunter satisfaction within Alabama have not been investigated. Further, little is known regarding the relationship between landscape composition and gobbling activity, which is an important determinant of hunter satisfaction. Thus, we deployed 91 autonomous recording units (ARUs) on public and private study sites across Alabama to investigate how different factors impacted gobbling activity and chronology of male wild turkeys. We deployed ARUs from 1 March to 30 June during 2022 and 2023 and recorded all ambient sound from 1 hr before sunrise to 5 hr after. A small, 6-day difference in peak gobbling occurred from north to south Alabama, but the difference was likely inadequate to warrant region-specific hunting seasons. Gobbling activity was suppressed on transitional and moist days. Gobbling activity was positively associated with cumulative male removal, but not to other measures of hunting activity. The proportion of gobbling activity captured by the hunting season was greater on private land, where the season started one-week earlier than on public land. In general, our results showed that later seasons captured less gobbling activity. Gobble detection rates increased with the amount of early successional and mature bottomland forest cover at the landscape level, and were positively associated with forb ground cover at the local (ARU) scale. Overall, our research provides state agencies and managers with important information on the impact of changes in season frameworks, along with how latitude, humidity, hunting, and habitat characteristics affect gobbling in wild turkey populations
Lean-On Bracing Refined Design Methods and Field Assessment
No full textCross-frames are critical for the stability of steel bridges during construction and play a significant role in completed bridges. Historically, brace locations have been regions of fatigue concerns, and each brace requires significant handling and processing during fabrication. The braces represent one of the most expensive bridge components per unit weight. Therefore, there are significant benefits to minimizing the number of cross-frames in a bridge in terms of economics and structural performance.
Lean-on bracing concepts replace select cross-frames in certain bracing lines with top and bottom struts, which allow a single cross-frame to brace several girders as a method of minimizing the number of cross-frames in a bridge. Lean-on concepts were developed for the Texas
Department of Transportation (TxDOT) in the early 2000s. Previous studies developed design guidelines, but recent applications of lean-on bracing in TxDOT bridge designs demonstrated the need for improved efficiency and clarity.
The stiffness and strength of a given line of bracing are functions of the number and location of cross-frames in the line, as well as the specific cross-frame geometry (X-, K-, or Z-frames). While previous lean-on bracing equations were applicable to systems with one X- or Z-shaped cross-frame positioned in an exterior bay, derivations and model validation have been completed to extend the application of the design guidance. Derived equations with simplified design expressions for lean-on brace stiffness and strength will be discussed in terms of stability implications, with consideration for future application
Rhodium and Cobalt Transition Metal Catalysis for Heteroarene Dearomatization and Natural Product Synthesis
No full textNitrogen heterocycles are ubiquitous in pharmaceuticals, agrochemicals, and natural products and occur often as partially or fully saturated non-aromatic six-membered rings. Much work has gone into the development of methodologies for the synthesis of non-aromatic nitrogen heterocycles. However, substrate limitations, and/or the need for reagents and starting materials that require multistep syntheses have left room for improvement in the synthesis of non-aromatic nitrogen heterocycles. The transition metal mediated asymmetric dearomatization of activated heteroarenium salts yields dihydroheteroarene compounds that can act as building blocks to access either functionalized pyridines through oxidation, or tetrahydropyridines and piperidines through functionalization or reduction. Further the use of transition metal catalysis would allow for the development of substrate independent regio- and enantioselective dearomatization methods. To date no one solution has been reported that allows for the control of both enantioselectivity and regioselectivity in the dearomatization of pyridiniums to yield chiral dihydropyridines.
This thesis focused on the development of regioselective and enantioselective pyridinium dearomatization methodologies. Chapter 2 focuses on the first reported rhodium catalyzed C2-selective dearomatization of pyridinium salts derived from nicotinic acid esters to generate chiral dihydropyridines. Chapter 3 extends this same approach to the synthesis of dinitrogen heterocycles in the form of quinoxalines. Chapter 4 reports the use of the developed rhodium-based asymmetric dearomatization methodologies to access chiral, natural products nuphar indolizidine and deoxylasubine II. Finally, Chapter 5 reports preliminary data on the first reported asymmetric dearomatization of quinolinium salts utilizing a cost-effective and less toxic, earth abundant metal, cobalt, and several novel binaphthalene Schiff-base-type ligands
Optimizing copper applications for the control of harmful algal blooms
No full textHarmful algal blooms (HABs) degrade water quality, disrupt aquatic ecosystems, and introduce off-flavors to aquaculture products and drinking water. Copper (Cu) sulfate pentahydrate is commonly used to control HABs due to its high efficacy and widespread federal approval. However, environmental concerns and the risk of phytoplankton developing copper tolerance with repeated use highlight the need for optimized treatment strategies. This thesis used large-scale mesocosm experiments to investigate Cu tolerance in phytoplankton communities and assess CO2-enhanced, low-dose Cu treatments as alternative approaches for HAB control.
We compared phytoplankton responses to standard (350 µg/L Cu) and low (170 µg/L Cu) doses in a mesocosm experiment. Results showed that both standard and low doses achieved over 99% reduction in cyanobacteria within the first week. After three days, tolerance in phytoplankton to Cu increased significantly (up to 12.4x) in treated communities, especially among Cu-tolerant chlorophytes, suggesting a potential shift toward Cu-resilient communities.
An additional mesocosm experiment was conducted using a CO2 addition to reduce pH. This addition was hypothesized to increase Cu toxicity making treatment effective at even lower Cu doses of 80 µg/L and 20 µg/L (20% and 5% of standard recommendations). The CO2-enhanced treatments further improved copper efficacy, achieving 94% cyanobacteria removal and 95% off-flavor reduction while promoting a 512% increase in beneficial chlorophytes, an effect not observed without CO2. These findings suggest that a CO2 addition can enhance copper treatment efficiency, reduce required dosages, and support beneficial phytoplankton. This combined approach provides valuable insights for water managers aiming to balance effective HAB control with long-term sustainability in aquatic ecosystems
Avoiding k-Rainbow Graphs in Edge Colorings of Kn and other Families of Graphs
Get PDFA simple graph, G, avoids a k-rainbow edge coloring if any color appears on at least k + 1 edges of G. For any positive integer k, the k-Anti-Ramsey Number, ARk(G,H), is the maximum number of colors in an edge coloring of the graph H such that no k-rainbow edge colored copy of G is a subgraph of H. This work will discuss ARk(G,H) where H is various types of graphs. In particular, this work will focus on ARk(G,Kn) and define G as ARk-bounded if ARk(G,Kn) is bounded by some positive integer c for all n sufficiently large. Additionally, we will say G is ARk-unbounded is no such positive integer exists. In this work we will determine which simple graphs are ARk-bounded for any k. We will provide a lower bound for ARk(G,Kn) if G is ARk-unbounded and an upper bound for ARk(G,Kn) if G is ARk-bounded. We will also determine ARk(G,H) for various graphs G, H where H is not a complete graph
Access to Healthcare in the Black Belt Region of the USA
No full textEven though the United States is highly developed, it lacks a universal healthcare system, leading to unequal access and health outcomes. These gaps are noticeable in marginalized areas like the Black Belt region, where the lack of hospitals nearby worsen current issues. This research include two separate studies addressing these disparities. The first study assessed healthcare accessibility within a 35-minute drive in Lamar, Lowndes, Perry, and Pickens Counties, revealing that 65%, 40%, 44%, and 33% of the populations, respectively, live beyond this range. The second study examined Medicaid expansion’s impact in 2014 and 2020. Using independent and paired samples T-tests, it found statistically significant difference in enrollment rates between states that expanded Medicaid and those that did not. In 2020, states with Medicaid expansion saw a significant rise in enrollment, highlighting its effect. These findings provide valuable insights for policymakers to address healthcare disparities
Exploring Causal Factors that Impact Local Climate Variability to Enhance Community Preparedness and Mitigation Strategies for Coastal Small and Medium-Sized Cities (SMSC) and Counties
No full textThis dissertation investigates the causal factors affecting local climate variability in coastal small and medium-sized cities (SMSC) and counties, aiming to enhance community preparedness and formulate effective mitigation strategies. It comprises an introductory chapter, a concluding analysis, and four case studies. Chapter 2 examines rapid urbanization in the coastal city of Thiruvananthapuram (TMC), India, revealing that increased urban land cover, driven by reduced vegetation, contributes to rising temperatures and altered precipitation patterns. Recommendations include enhancing green cover and reducing impervious surfaces to mitigate these effects. Chapter 3 analyzes rural migration and settlement patterns in the Southeastern United States (SE US) coastal SMSC ad counties, highlighting the dual pressures of economic growth and environmental vulnerability in areas like Norfolk, Virginia (VA), and Collier County, Florida (FL). It emphasizes the necessity for sustainable urban planning to address infrastructure strains and natural hazards. Chapter 4 discusses lessons learned from Hurricane Irma and Hurricane Ian, emphasizing the importance of enhanced building codes, emergency management, and community engagement for disaster preparedness in coastal counties. Chapter 5 explores building volume distributions in Collier County and Norfolk using validation techniques for power law and log-normal distribution, offering insights for urban planning and flood risk management. The dissertation underscores the interconnectedness of these studies and the need for holistic, data-driven approaches to climate change mitigation. By advocating for innovative technologies and community involvement, it highlights the urgent need for resilient and sustainable urban environments amidst ongoing population growth and climate challenges. Future research should build on these findings to further address the complexities facing coastal communities globally