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SoyNASNet: An optimized neural architecture for soybean leaf disease detection
No full textSoybean (Glycine max) plays a vital role in global food systems, yet its productivity is often reduced by diseases that can lead to significant yield losses, ranging from 8% to 25% annually, and costing up to $3.9 billion in the United States alone. To address this, early and precise detection of soybean diseases is essential. In this study, we utilize Neural Architecture Search (NAS) to develop an optimized deep learning model named SoyNASNet, designed for the Soybean Disease Image Dataset (ASDID), containing 9,422 images across eight disease classes. The dataset poses challenges, including class imbalance and visual similarity between classes. SoyNASNet achieves an accuracy of 98.3%, outperforming state-of-the-art models such as DenseNet121, ResNet50, Swin Transformer, and other. Key architectural parameters were optimized through NAS, and model interpretability was enhanced using filter visualization and Grad-CAM. The results highlight NAS’s potential in precision agriculture through scalable and explainable deep learning solutions
Asphalt durability improvements by way of specification advancements
No full textThe objective of this dissertation is to provide content through which industry and agencies can adjust and/or update standards and specifications, as appropriate, to accommodate the present-day needs of the asphalt industry towards producing more durable asphalt. A total of 78 asphalt mixtures and 9 asphalt binders were evaluated for up to 10 years of field aging to provide content that was analyzed to meet this objective. A full-scale aging site in Columbus, Mississippi was the focal point of the aging experiments. A major conclusion from this work was that Cantabro Mass Loss (CML) testing of cores was able to detect field aging for up to 10 years. It was also concluded that AASHTO R28 is capable of simulating over 5 years of field aging with 20 pressure aging vessel (PAV) hours at 100 degrees Celsius, at least for some conditions, away from the pavement surface. AASHTO R28 was not capable of simulating over about 2 years for these same conditions within 1.3 cm of the pavement surface. This dissertation produced a table of recommendations for manners to update the field aging simulation appendix of AASHTO T 401 that makes use of CML testing. Overall, this dissertation aimed to provide a unique contribution to the asphalt paving field by way of measurable outcomes toward ongoing work on AASHTO T 401 and the potential to provide data that could be useful relative to ongoing AASHTO R28 narratives to produce more durable asphalt mixes
Forensic analysis of fire-damaged aerospace carbon and graphite/epoxy composites
No full textPost-crash fires often impede accident reconstruction since the telltale fractographic evidence is obscured by combustion residues or the fires incinerate them. The aim of this work is to develop a treatment protocol for post-fire char removal while preserving the pre-existing mechanical failure features of carbon/epoxy composites. Preliminary tests explored ultrasonication in commonly used organic solvents and HNO3/H2SO4 solutions (in ambient conditions). Mechanically undamaged carbon/epoxy specimens were burned to produce charring. Since heated HNO3/H2SO4 solutions were more capable of removing char through oxidation, a direct heating process was adopted in succeeding experiments. In addition, char removal was attempted on mechanically failed graphite/epoxy composites after small flame burning. These following process parameters were varied: HNO3/H2SO4/H2O content, solution temperature, and immersion duration. Scanning electron microscopy was used for fire damage characterization and to examine composite surfaces after char removal. Irrespective of the high H2SO4 (~ 95.26 wt.%) content, the fiber surfaces remain obscured due to incomplete oxidation at low immersion times (t ≤ 1 min) in acid solutions with low HNO3 content (≤ 0.88 wt.%) when the temperature was maintained at ≤ 100 °C. In contrast, fracture surface degradation occurred when temperature and immersion time were high (T ≥170 °C and t ≥10 min) especially for higher HNO3 content (≥ 9.16 wt.%) solutions with reduced (but still high) H2SO4 content (~ 84 wt.%). However, optimal results were achieved with solutions of 3.12–8.07 wt.% HNO3 at 125–135 °C. The directly attributable failure features (DAFFs) for compression and flexure related failures were recovered minimal degradation from burned specimens before 5 min of immersion. The elevated temperatures of 125-135 °C combined with low water activity and high H2SO4 (≥ 85.21 wt.%) result in these exceptionally powerful oxidations of carbonaceous residues with limited fiber degradation. Structural scale experiments on PRSEUS open-hole specimens that were failed in tension established that HNO3/H2SO4 oxidations can eliminate combustion residues while preserving the underlying critical fiber-related fracture surfaces. The effectiveness of this surface treatment protocol in removing combustion residues represents a pivotal advancement in forensic methodologies for post-crash investigations of composite aircraft structures exposed to fuel-fed fires
Zeroizing trust in a naïve federated Zero Trust environment
No full textThe position of the United States on the global stage is predicated on information dominance and the ability to project power through cooperative engagements with mission partners in both wartime and peacetime. Recent cyber-attacks highlighted the need for a more robust cybersecurity posture. As the United States progresses toward the adoption of Zero Trust, it is incumbent on the Department of Defense to assess the impact to the ability to share data across strategic partnerships while securing the data of both the United States and its partners. This paper proposes research into ensuring an environment rooted in Zero Trust and intended to support data sharing with mission partners across a variety of partnerships and mission sets is able to maintain the tenets of Zero Trust when augmented by weak integration with mission partners\u27 identity solutions. This dissertation investigates the challenges and opportunities of implementing a weak federation in a Zero Trust architecture when mission need outweighs the associated cybersecurity risk. It is asserted that weak integration opens the aperture on the number of accounts capable of system access, which impacts the ability of the system to achieve the tenets of Zero Trust. Based on the assertion, which is demonstrated through simulation, a modification to the architecture is proposed to preregister users and standardize attributes as a means to mitigate the impacts to the authentication and authorization mechanisms. A mixed-method approach of mathematical analysis and simulation is used to assess the nonfederated, weak-integration and recommended architectures to determine the degree to which the negative impacts are mitigated. Additionally, it is asserted that a behavioral biometric-esque approach can be used to characterize the behavior of archetypes based on a standardized attribute model. A modified Adaptive Neuro Fuzzy Inference System was trained as a proof of concept to accept request data and user attributes to characterize behavior and provide a categorical context score that represents the likelihood that a request came from a user with the asserted attribute set. The expected contributions of this study include a strategy for improving cybersecurity posture while supporting weak integration attribute-based context generation that can be used to improve continuous authentication mechanisms
The role of K-12 educators in shaping STEM pathways: Examining social capital and self-efficacy in STEM education
No full textThis dissertation examines the impact of K-12 educators on students’ pathways in STEM (Science, Technology, Engineering, and Mathematics) by focusing on two main factors: the social capital of K-12 and elementary school teachers and the self-efficacy of preservice teachers in STEM education instruction. The first study investigates the social capital of first year engineering students, emphasizing the relationships and resources they gained during their K-12 education that influenced their decision to major in engineering. A quantitative study using survey data collected from first-year undergraduate engineering students indicates that K-12 educators play a crucial role by providing mentorship and resources that significantly affect students’ academic and career choices. The second study complements the first by examining the pedagogical content knowledge and perceived self-efficacy of preservice teachers in teaching STEM education. This mixed-methods study, which included a survey instrument known as the STEMPCK and semi-structured interviews, revealed that preservice teachers often lack sufficient STEM content knowledge, particularly in engineering. However, they demonstrated a solid understanding of pedagogical and 21st-century skills knowledge. Together, these studies highlight the critical role that K-12 educators play in fostering students’ aspirations in STEM fields. They also highlight the need to integrate STEM content knowledge into teacher preparation programs to equip future educators with the necessary knowledge, resources, and mentorship to cultivate a more diverse STEM workforce
Myxozoan diversity and life cycles in catfish production ponds in Mississippi, USA
No full textCatfish aquaculture is a critical industry in the United States and Mississippi in particular. The industry is beset by depredation, rising feed costs, competition with imports, and loss to disease. Chief among these is the myxozoan parasite and causative agent of proliferative gill disease, Henneguya ictaluri. In chapter 2, novel molecular markers for greater resolution in species identification of these parasites are provided, allowing more robust life cycle inference, species-level identifications, and inference of evolutionary relationships through molecular phylogenetic analyses. Chapters 3–5 apply the approaches developed in Chapter 2 to a broad array of taxa beyond catfish-infecting Henneguya spp. These included the marine parasites Kudoa hypoepicardialis from wild-caught lionfish Pterois volitans and Enteromyxum leei from Creole wrasse Clepticus parrae from a display aquarium in Mississippi, USA. Chapter 6 uses metagenomic analyses of fish, pond water, and feces from piscivorous birds and alligators to elucidate the effects of stocking rotations on myxozoan communities and potential mechanical vectors for transmission of myxozoans between environments. These data show that despite hybrid catfish being likely dead-end hosts for Henneguya ictaluri and contrary to studies in controlled experimental conditions, this parasite persists regardless of stocking strategy. This underscores the need for greater biosecurity and the development of treatment and prophylactic measures for addressing this devastating myxozoan parasite
Evaluating rainfall sensitivity over land to tropical cyclone parameters using idealized WRF
No full textTropical cyclones (TCs) are extreme weather events impacting the United States nearly every year. These events often cause severe damage due to the associated responses they produce including storm surge and rainfall, and the accurate estimation of these TC hazards is necessary to support coastal engineering, risk assessment, and emergency management activities. Evaluating TC-driven hazards is often done in combination with numerical models to simulate how environmental interactions alter the physical processes and responses of these storms. The purpose of this study was to simulate synthetic TC events using the Advanced Weather Research and Forecasting (WRF) model to understand how rainfall varies in relation to the parameters defining each storm. Based on the results, rainfall sensitivity to changes in the magnitudes of these TC parameters was assessed to quantify differences both quantitatively and spatially. In particular, the rainfall sensitivity over land was evaluated given the importance of coastal-compound flooding hazards
Modifiers as floating information: A case against seamless modifier integration
No full textSeveral studies have found a benefit for modified nouns (e.g., adorable puppy), such that they are easier to retrieve from memory compared to unmodified nouns (e.g., puppy) during language comprehension. However, there is some evidence that when the intrinsic semantic qualities of the modified noun do not fully match the content of modifiers (e.g., dangerous puppy), integration of the target noun and the modifiers becomes difficult, and the modification benefit is lost. If this integration difficulty can occur due to the semantic qualities of the modified noun, could it be the case that the semantic qualities of other competing nouns in the sentence (e.g., kitten) may have similar effects? To answer this question, two studies were conducted which manipulated how well modifiers matched the semantic qualities of two nouns in memory and measured the strength of the benefit during language production (experiment 1) and online comprehension (experiment 2)
The influence of nature on design: A focus on the flora and fauna influence on 18th and 19th century decorative arts
No full textThis study aims to assist interior designers and preservationists in enhancing interior decoration by appreciating decorative arts in a historically accurate and visually appealing manner. It places a strong emphasis on the profound influence of nature on design. For centuries, creatives have drawn inspiration from nature, leading to the creation of unique design elements and decorative objects. In the eighteenth and nineteenth centuries, naturalists produced floral and faunal prints that reflected this inspiration. Nature\u27s impact on design extends beyond aesthetics; it also affects how individuals feel within a space. The environment one person inhabits influences his or her state of being. An anonymous survey was conducted to gather insights from this body of research, ultimately demonstrating whether nature impacts design. Two hundred and eighty survey participants were recorded. The survey was distributed via email to Mississippi State students and workers in the field of art, architecture, and design. Additionally, the survey was shared on social media. Data demonstrates that most all survey participants were more knowledgeable on the notion that botanical illustrations of the eighteenth and nineteenth centuries potentially affected interior design, growing the popularity of natural motifs seen on various forms of decorative art pieces
“Take This Job and Shove It”: How Black Women’s Fight for Economic Rights Informed Their Participation in the Broader Social Movements of the Twentieth Century
Get PDFThis thesis examines the vital role of Black women in the American labor movement during the twentieth century, emphasizing how their leadership and union participation were central to both labor organizing and the broader fight for human rights. Black women workers navigated and resisted the effects of racism, sexism, and class exploitation in a century marked by industrial expansion, economic upheaval, and major civil rights struggles. Far from passive participants, they emerged as key organizers, negotiators, and strategists in their communities, labor unions, and national movements. Additionally, their work extended beyond their demands for better wages and safer working conditions. It also included broader goals such as political representation, racial justice, and gender equity. The thesis explores how Black women’s labor activism was inherently intersectional, with their fight for economic justice inseparable from social and political liberation. Activists such as Claudia Jones, Nannie Helen Burroughs, and Addie Waites Hunton illustrate the ways in which Black women intertwined the labor movement with grassroots organizing principles and a vision for collective empowerment. The research herein also considers lesser-known local and regional efforts, demonstrating that Black women’s leadership was both widespread and transformative. By centering Black women’s experiences, this work challenges dominant labor narratives that have historically marginalized their contributions in discussions of the Popular Front. It positions Black women as the perpetuators of an intersectional labor movement, one that reflected the combined struggles against racial, gendered, and economic oppression throughout the twentieth century in the United States