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Experimental Investigation and Literature Review of Phosphorus Removal in Flow-Through Systems During Various Engineering Applications
No full textThe overloading of phosphorus (P) into aquatic environments over the past several decades has triggered widespread water quality deterioration, harmful algal blooms, and eutrophication. Due to their natural abundance, cost effectiveness, and excellent physicochemical properties and functionalities, carbonaceous materials (e.g., activated carbon and biochar) have been used to sorptively remove P from water and wastewater during various engineering applications. This thesis integrates both experimental investigation and literature review of carbonaceous materials, especially biochars, for P removal in flow-through systems during engineering applications. Laboratory experimental results showed that activated carbon and biochar (especially iron oxide-modified biochars) can effectively remove P in flow-through packed columns, due to their large surface area, rich pore structure, and favorable sites (e.g., iron oxides) for P sorption. Literature review suggests that biochar can be integrated into various flow-through treatment systems for enhanced P removal, including constructed wetlands, bioretention systems, bioreactors, trenches, bioinfiltration systems, and point-of-use household treatment systems. This is likely because biochar can introduce additional physical, chemical, and biological benefits for these treatment systems for enhanced P removal. Findings of this thesis support the advantages of integrating the cost-effective and efficient biochars (and modified biochars) for enhanced P removal during various flow-through engineering applications
Combinatorial Methods for Undergraduate Mathematics Curriculum Analysis & Design
Full text linkStudent retention is a significant issue in Research in Undergraduate Mathematics Education (RUME), and freshman calculus is notorious for “weeding out” students from STEM majors. Since the late 1980s, various attempts have been made to remedy Calculus courses around the United States. However, the percentage of students earning grades of D, F, W, or I (the DFWI rate) remains relatively high compared to freshman courses in other disciplines. Through a collection of research projects, this dissertation explores the theme of misalignment in various aspects of the university Calculus I curriculum by employing novel applications of combinatorics to mathematics education research. This is an example of Mathematics Discipline-Based Education Research (Math DBER), which is an emerging field that leverages mathematics methodologies in RUME
Using Isotopes to Understand the Movement Patterns and Diet of Albatross and Pterosaurs
No full textIsotopes are useful tools for elucidating ecological unknowns in modern and prehistoric organisms. Two of the organisms that have lacked the application of 87Sr/86Sr methodologies to understand their movement patterns are albatross and pterosaurs. Albatross has also been mentioned many times within the literature as a modern analog for pterosaur flight behavior. Along with strontium, there is a severe lack of dietary evidence resulting from isotopic studies focusing on the pterosaur's fossil record. Within this thesis, albatross 87Sr/86Sr compositions will serve as an isotopic baseline to be used as a comparison to pterosaur isotopic signatures and will provide additional context on the level of variability recorded in 87Sr/86Sr during extended trans-oceanic flying. δ13C, δ15N will be used as a baseline for pterosaur dietary 44Ca/42Ca signals. In Chapter 1, 87Sr/86Sr and δ13C within bone and feather tissues, along with δ18O compositions in bone, were used to understand six differing albatross species movement patterns. Our data showed a strong marine signal in the 87Sr/86Sr bone material, while the feathers showed some pull towards volcanic islands, while δ13C and δ18O within their respective tissues showed partitioning between species in relation to their movement patterns. δ13C, δ15N showed dietary partitioning between species. Chapter 2 shows our pterosaur samples lacking any marine 87Sr/86Sr compositions in both sampled formations across all clades, while our 44Ca/42Ca compositions showed niche partitioning between pterosaur clades. This thesis is the first to apply 87Sr/86Sr methodologies to albatross. It has been shown that 87Sr/86Sr on long-term scales in albatrosses show almost pure marine compositions and lack the nuance of compositions closer to terrestrial values seen within the shorter-term feathers. This baseline has shown that our pterosaur material compositions are not analogous to albatross ecological behaviors, and new thought processes on pterosaur flight behaviors should be explored. Along with this, other clades of pterosaurs should be studied with 87Sr/86Sr to understand the correctness of their modern analogs. Our dietary signals in our albatross samples showed known dietary composition seen in the literature, but it shows that our pterosaur samples, which range across differing clades, should also see partitioning of diets, which we do see. Our pterosaur dietary data shows the usefulness of applying 44Ca/42Ca to the pterosaur fossil record and should be applied to other clades
Automatic Speech Disorder Assessment for Children’s Speech Disorder
No full textSpeech disorders in children present persistent challenges for early detection and intervention due to the complex, variable, and context-dependent nature of developing speech. Traditional automatic speech disorder detection (ASDD) systems, which rely heavily on handcrafted features such as Mel-Frequency Cepstral Coefficients (MFCCs), often struggle to capture the nuanced articulatory and prosodic patterns that characterize pediatric speech impairments. Recent advances in transformer-based deep learning architectures and self-supervised learning (SSL) offer promising alternatives for building more robust and interpretable ASDD systems.
This dissertation investigates three complementary approaches to advancing ASDD through the integration of modern representation learning techniques. The first study examines the use of the Vision Transformer (ViT) architecture applied to MFCC features for the classification of disordered and non-disordered child speech. By leveraging the ViT’s patch-based attention mechanism, the study demonstrates that transformer-based models can achieve improved performance over conventional machine learning classifiers when applied to fixed acoustic feature representations.
The second study evaluates the effectiveness of SSL-based speech representations, specifically those derived from wav2vec 2.0 and HuBERT, in detecting speech disorders in children. Through layer-wise analysis and speaker-independent classification experiments, this study confirms that SSL representations outperform MFCCs by capturing more detailed, context-aware acoustic cues.
The third study explores an SSL-based perceptual similarity framework for measuring acoustic distances between speech samples. Using dynamic time warping (DTW) in the high-dimensional embedding space produced by SSL models, the study calculates similarity scores between utterances without relying on textual transcriptions. These distance metrics are shown to correlate strongly with clinical judgments of speech pronunciation accuracy and disorder severity, supporting their potential use in continuous monitoring or pre-diagnostic screening.
Together, these studies provide a comprehensive evaluation of transformer-based and SSL-driven approaches for pediatric ASDD. The results highlight the advantages of using deep contextualized speech representations in terms of classification accuracy, robustness, and interpretability. The contributions offer a foundation for developing clinically viable tools to support early identification and longitudinal assessment of speech sound disorders in children
A field and geochemical investigation of tourmaline occurrences around the Hog Mountain gold deposit, AL
No full textTourmaline can be a powerful mineral as its properties allow it to preserve information that can be used to uncover its geologic history. Abundant, previously undocumented occurrences of tourmaline have been discovered in the Wedowee Group adjacent to the Hog Mountain orogenic gold deposit in Tallapoosa County, Alabama. Field work revealed four distinct groups: pegmatitic, metamorphic, quartz-hosted, and aggregate, which were compared to tourmaline within a Hog Mountain tonalite (hmt) quartz vein within the gold deposit. Petrography, geochemical analyses, and microscopic imaging were used to determine the mineralogy, textures, elemental concentrations, and compositional zoning patterns of 21 samples. Trace element analyses revealed distinct compositions of each group; the pegmatitic tourmaline is relatively enriched in Pb, metamorphic has the highest Li concentrations, aggregate tourmaline is relatively enriched in Ce, and tourmaline from the hmt quartz vein contains high Sr, Sn, and Pb. Elemental maps show that zoning reflects changes in Fe, Mg, Ti, and occasionally other elements, indicating changes in fluid composition during mineral growth or diffusion during metamorphism. These findings demonstrate that the tourmaline in the Hog Mountain area has great potential as a geochemical indicator and geochronological target. They suggest that further analysis of the tourmaline and their host rocks in and around the orogenic gold deposit could refine the geologic history of Hog Mountain
Evaluation of the Impact of Processing Techniques and Labeling on Poultry Sensory Attributes, Consumer Acceptance, and Purchase Behavior
No full textAnimal welfare is a topic of discussion for the animal agriculture industry as this niche market has been growing over the past decade. In poultry specifically, there are many various methods used to promote animal welfare. However, they primarily entail production practices and not processing. In processing, there are two stunning methods primarily used. In electrical stunning, the most common, birds are live shackled then enter an electrical water bath to render them unconscious prior to exsanguination. Gas stunning is deemed an effective alternative with higher regard to animal welfare where birds stay in their coops and then enter a gas chamber where oxygen is replaced with gases such as carbon dioxide. In the first study, the objective was to determine if there were any differences between the two stunning methods consumer acceptance (n=90, n=93 respectively) and if there are any differences in sensory attributes over time using vacuum packaging and non-vacuum packaging. Meanwhile, the second study investigated if there were any differences in consumer acceptance, purchase intention, and willingness to pay for identical chicken breast bites with common value-added labels (All-Natural, USDA Organic) and the Humanely Processed label (n=116). These studies showed that there were minimal to no differences in consumer acceptance, sensory attributes, purchase intention, and willingness to pay for electrical and gas stunned chicken and different labeled identical chicken breast bites. However, consumers were not willing to pay a premium (above market average) for either value-added label or the Humanely Processed label demonstrating the need for pricing to be reasonable in terms of consumer perception. These studies provided key insights for poultry companies if different processing plants have different stunning techniques used there will be no differences in consumer acceptance. In addition, it demonstrated that the willingness to pay and purchase intention for Humanely Processed was similar to common value-added labels on the market indicating to marketers that there may be a niche animal welfare market growing in poultry products
Field Inspections and Monitoring of Continuous Deck Slabs on Prestressed Concrete Bridges for Development of Refined Details
Full text linkExpansion joints are used in bridges to allow for the unrestrained movement of the
superstructure. However, due to the need for frequent maintenance, continuous deck details have
been developed to replace them. This study evaluated the current detail Alabama Department of
Transportation (ALDOT) uses to make the deck slab continuous at pier bent locations (termed
closed joints) in prestressed girder bridges instead of using expansion joints (termed open joints).
The study inspected five bridges across Alabama to assess the performance of the in-service detail.
The inspected bridges varied in properties, including the span and overall lengths, skew angles,
girder types, ages, and environments. Based on visual observations, the study found that the factor
that most affected the visual performance of the deck was the detailing and tooling of the
construction joint. The main damage observed at these closed joints was due to traffic wear and
did not cause structural concern. To evaluate the behavior of and the demands on the closed-joint
detail further, the study then monitored a bridge for a year. The behavior of both open and closed
joints were monitored. The demands and movements at the girder ends were captured during this
period, with a focus on the effects of thermal demands. The measured rotations from the monitored
bents were similar in magnitude regardless of the detail used for the joint, indicating little to no
rotational restraint was provided at the closed joint. The rotations measured from field monitoring
indicated that using the AASHTO design values for rotation from thermal gradients will work for
future design. For recommending values for future design, demands from live load and time-dependent
effects were superimposed using guidance from AASHTO
The Impact of Feed Additives and Calcium Concentration and Source on Broiler Performance, Nutrient Utilization, and Intestinal Health Under Different Disease States
No full textOptimizing broiler nutrition is essential for maintaining performance, enhancing nutrient utilization, and supporting intestinal health, especially when birds face various disease challenges. The reduction or removal of antibiotic growth promoters (AGP) in broilers has presented additional challenges for nutritionists, necessitating the development of alternative feeding strategies that sustain broiler performance and health while minimizing feed costs. These feeding strategies should aim to replicate performance outcomes previously achieved with AGP, though this remains difficult due to the complex mode of action of AGP. The present research explored two nutritional strategies to address AGP removal in broiler feeding: (1) feed additives and (2) diet manipulation. Feed additives like phytase and butyrate may help to alleviate the negative effects of AGP removal on broiler growth. Phytase, an exogenous enzyme, is commonly included in broiler diets to degrade phytate and enhance phosphorus (P) digestibility. Butyrate, an organic acid, improves intestinal health by modulating the microbiota and providing energy to intestinal epithelia. To evaluate the first nutritional strategy, broilers were provided with 1 of 9 treatments that included varying levels of phytase, calcium butyrate (CB), and bacitracin methylene disalicylate (BMD). Supplementing BMD increased early broiler body weight (BW), particularly when combined with 1,500 FTU/kg of phytase, but not with 500 FTU/kg. Depending on phytase inclusion, broilers fed a diet with CB exhibited similar BW compared to those fed BMD. Additionally, phytase at 1,500 FTU/kg enhanced fat and P digestibility, and apparent ileal digestible energy (AIDE). Intestinal physiology and cecal microbiota composition were influenced by CB and BMD, with changes in villus height, tight-junction gene expression, and cecal microbial evenness, depending on dietary phytase concentrations. These findings highlight the complex interactions between feed additives and their potential to modulate broiler performance and intestinal health. The second nutritional strategy involved manipulating dietary components, such as calcium concentration and limestone particle size, to help mitigate performance and mortality impacts from enteric diseases. Broiler diets are often unintentionally formulated with excess calcium, which may exacerbate necrotic enteritis by supporting NetB and α-toxin activity, leading to reduced nutrient utilization and compromising broiler health. Excess calcium can also increase calcium-phytate formation, resulting in undigested nutrients that become available to intestinal microbiota, potentially promoting proliferation of pathogenic bacteria. To evaluate this strategy, broilers were assigned to 1 of 7 treatments, including an unchallenged control and 6 enterically challenged groups fed diets with varying limestone particle sizes and calcium concentrations. The enteric challenge reduced broiler performance without affecting mortality. Reducing dietary calcium by 0.10 percentage units from recommended levels maintained broiler performance, tibia mineralization, and AIDE during an enteric challenge. Furthermore, calcium and P digestibility increased when dietary calcium was reduced. However, feed conversion and nutrient utilization responses varied depending on limestone particle size. Understanding the interaction between dietary calcium and limestone particle size could help to mitigate the impact of enteric diseases. Ultimately, to develop sustainable solutions that enhance broiler growth and health, broiler nutritionists must continue exploring AGP alternatives and further understand interactions between feed additives and dietary components
Data Driven Approaches for Nonlinear System Identification and Control of Hardware in the Loop Systems
No full textSystem identification can play in important role in the engineering design process. Generating a high-fidelity model of a system can lead to improved performance and reduced costs. There are many ways to create these models but this work will focus on data driven approaches, specifically machine learning based methods. The major classes of machine learning techniques viewed are long short-term memory networks, nonlinear autoregressive models, and feed-forward networks with lagged inputs. These modeling techniques are explored in use for creating models of a hardware in the loop testing (HWIL) system and a vehicle with the focus being the reduction of mean squared error between the estimated outputs and the true outputs. The feed-forward network for the HWIL system is then used to create a trajectory optimization network to improve the performance of the system by reducing the tracking error to a reference input. The flexibility and generality of these machine learning based data driven modeling techniques provides a viable option for the creation of models for various unknown complex systems
Nutritional applications of arginine functionality to support broiler chicken health and performance.
No full textFour experiments were conducted to evaluate the effects of dietary dArg:dLys ratio on the performance and health of broilers subjected to different immunological, environmental, and pathogenic stress models. Experiment 1 used intradermal (i.d.) lipopolysaccharide (LPS) injections at 40 d to stimulate the innate immune response, and the local (tissue) and systemic (blood) inflammatory responses were evaluated at 0, 6, 24, and 48 h post-injection. Experiments 2 and 3 used a cyclic heat stress (HS) model in Ross 708 and Cobb 500 genotypes during the finisher phase to mimic the environmental challenges experienced by broilers in temperate zones during the summer and in tropical regions year-round. Experiment 4 utilized oral gavages of a 10-fold dose of a live coccidiosis vaccine at 15 d followed by ~10^7 CFU Clostridium perfringens at 19 and 20 d to replicate enteric challenge similar to what may be encountered by broilers in the field. In each experiment, dietary treatments included multiple (5 to 7) dietary dArg:dLys ratios that ranged from below to well above the current breeder recommendations. Linear and quadratic contrasts as well as regression analyses were used to evaluate dose-responses of dependent variables across increasing dArg:dLys ratios. In experiment 1, the local and systemic inflammatory response to i.d. injected LPS was dominated by an increase in heterophils (H) and a drop or no effect in lymphocyte (L) populations. On average, there was a linear increase in tissue and blood H with increasing Arg that also translated to a higher H:L ratio. Likely, this response was mediated by nitric oxide (NO), which increased linearly with increasing dArg:dLys ratio at 6 h post-injection. Concentration of alpha-1-acid glycoprotein (AGP) in the plasma and relative expression of IL-1β, IL-6, and IL-8 mRNA levels in tissue also responded in a dose-dependent manner to dietary Arg. In experiments 2 and 3, feed conversation ratio (FCR) was linearly improved during the finisher phase with increasing dArg:dLys ratio in both genotypes, but body weight gain (BWG) and feed intake were not affected. At 32, 38, and 46 d post-hatch, HS increased cloacal temperatures by approximately 1.6ºC, and dArg:dLys influenced body temperature dose-dependently in the Ross genotype only and not the Cobb. For processing characteristics, there were linear increases in chilled carcass and tender weights and yields and quadratic responses for breast fillet and total breast weights and yields in the Ross genotype. In the Cobb genotype, there was a quadratic response for fat pad weight and yield and linear increases in thigh and drum weights. In experiment 4, the enteric challenge significantly impaired growth performance during all periods, increased plasma NO and AGP concentration, and decreased ileal secretory IgA secretion. During the challenge recovery period (22 to 29 d), FCR of challenged birds improved linearly with increasing dArg:dLys, and increasing dArg:dLys ratio quadratically improved BWG and FCR of challenged birds during the grower phase and cumulatively. Dietary Arg did not significantly affect 22 d plasma NO or AGP concentration in this trial. For processing characteristics, feeding 1.29 dArg:dLys improved chilled carcass yield compared to birds fed 1.05 dArg:dLys. Overall, the results of these experiments indicate that increased dArg:dLys ratio beyond the current recommendations of 1.05 to 1.10 may be beneficial for improving broiler performance and health. This is likely due to the secondary metabolic functions of Arg, including synthesis of NO, that has diverse roles in supporting immunity and vasodilation