Doctoral Dissertations
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ItemDESIGN, SIMULATION AND ANALYSIS OF A NOVEL ROTARY VALVE FOR IMPROVEMENT IN THE EFFICIENCY OF AN INTERNAL COMBUSTION ENGINE(Middle Tennessee State University, 2024)Numerous studies have concentrated on enhancing the efficiency of internal combustion engines through various means, including refined design, superior materials, and regenerative technologies. Toyota recently reported a 40% gasoline engine efficiency with their Prius model in 2016. However, further research is warranted for improvement towards reaching the theoretical value of 73% efficiency as outlined by the Carnot Theorem. The first section of this dissertation gives an in-depth introduction of internal combustion engine from aspects including the history and the popular modern design as well as the history of the inventions of rotary valve engines. In the second section, the concept of using rotary valve instead of the conventional poppet valve for internal combustion engine is proposed. The study lists major drawbacks of the conventional poppet valve and explains the advantages of the rotary valve in general. A novel vertical positioned, servo motor driven, bell shape rotary valve is proposed to potentially improve the efficiency of a known conventional valve designed engine. The data of the new design is compared to the conventional poppet valve design with respect to several parameters to discuss its working principle and advantages over the conventional valve mechanism. Modeling is performed using Python programming to predict the valve opening mechanism. The experimental design is setup to control and tune different parameters accordingly within the reasonable range of engine speed viz. 1000-6000 RPM to simulate various working conditions. The maximum opening area for the rotary valve is calculated to be 0.795 sq.in which is smaller than the poppet valve’s area of 1.315 sq.in. However, under an example of 2900 RPM, the rotary valve was able to remain fully opened with constant efficiency of about 54% from 40 to 160 degrees of the crankshaft angle, while the poppet valve achieves 88% efficiency at 90 degree of the crankshaft angle and the efficiency significantly drops on either side of the maximum. Calculation shows that the proposed rotary valve can gain better performance with engine speed below 4400 RPM which is acceptable for real world use. Building on these findings, the third section develops and improves the rotary valve mechanism and the engine design. With key parameters such as displacement, cylinder bore, stroke, and compression ratio remaining the same, a transvers positioned, servo motor driven, spherical shape rotary valve is introduced. Instead of retrofitting the existing engine head with the bell-shaped valve, a new engine head design is developed, aiming to minimize the overall number of components required. A new spindle port shape is proposed, accompanied by a comparative calculation with the traditional circular shape. The valve flow coefficient prediction and in-cylinder pressure prediction are performed followed by volumetric efficiency prediction. An engine simulation based on the ideal Otto cycle is conducted with adequate predictions and parameter settings. The results reveal that the spherical shape rotary valve achieves a valve opening area comparable to that of the conventional poppet valve. Additionally, the spindle valve opening port shape delivers a volumetric efficiency gain of up to 3% compared to the circular shape at the same crankshaft angle. This improvement in volumetric efficiency is attributed to the engine's kinematics and mechanical engineering principles. The rapid creation of valve opening area by the rotary valve during the intake process results in very low negative work, as depicted in the P-V diagram from the engine simulation. Overall, these findings underscore the potential of the spherical shape rotary valve and spindle valve opening port shape to enhance engine performance and efficiency, offering valuable insights for further advancements in internal combustion engine design.
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ItemAdvancing Digital Papyrology: Machine Learning and Blockchain Tools for Modernizing the Study of Ancient Greek Manuscripts(Middle Tennessee State University, 2024)The study and preservation of ancient Greek papyri poses unique challenges due to the degraded and fragmented state of these highly damaged, ancient manuscripts. While digital imaging has aided in documenting these texts, manual transcription by experts remains a formidable bottleneck. In my work I present novel machine learning and blockchain-based approaches designed to accelerate and streamline the transcription and archiving of papyrological manuscripts. Key to this work is the creation of crowdsourced datasets of ancient Greek character images, annotated through a crowdsourcing initiative, that enable the training of deep learning models for character detection, segmentation, and recognition. Other contributions include augmenting datasets with synthetically generated characters to reduce sampling bias, and techniques for identifying annotation uncertainty via ensemble modeling to improve classification accuracy. The models and algorithms created in these works form the core of a pipeline that combines human oversight with automated processes for diplomatic transcription of papyrus fragments. Current and future work, based on these contributions, includes advances in optical manuscript dating an novel approaches to character spotting. To support collaborative scholarship within the field of papyrology, a blockchain framework utilizing smart contracts and decentralized storage is proposed for managing versions of transcribed texts. Implemented as a prototype, this framework demonstrates feasibility and potential benefits over traditional editorial workflows. Collectively, the methods developed aim to provide an AI-assisted platform tailored for papyrologists and other humanities researchers. By uniting machine learning, human computation, and distributed ledger technologies, this interdisciplinary research proposes a modernized paradigm for studying the ancient world through its surviving manuscripts.
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ItemThe Right Time for Process(ing): Trauma-Informed and Student-Informed Care Pedagogy in FYC at the Two-Year College(Middle Tennessee State University, 2024)ABSTRACT In this dissertation, I use a qualitative interview study to explore the student experience of writing about personal trauma in first-year composition (FYC). Based on my ten study narrators, all community college students who chose to write about a traumatic experience for an essay in FYC, I consider that FYC may be perceived by some students as a kairotic space -- the right time and right place -- to write about a trauma, perhaps for the first time. Because students may choose to write about a traumatic experience, whether or not we invite it, I also consider how trauma-informed writing pedagogy may help instructors respond in due measure. To highlight the kairotic nature of their experiences at key points during the writing process, I organize narrator quotes according to a chronological sequence: first, when they decided to write about their topic (Ch. 2: Opportunity), second, when they worked through the drafting process (Ch. 3: Process), and third, when they received feedback and grades from their instructor (Ch. 4: Response). I analyze their quotes alongside composition pedagogy and trauma-informed pedagogy. What separates my study from other trauma-informed writing pedagogy scholarship is that it centers student voices, highlighting the ways in which student experiences align with and depart from established pedagogy. Based on my study narrators, I propose that allowing students to write about trauma -- if they choose to -- and supporting them during the process can motivate students to achieve FYC rhetorical outcomes, cultivate academic belonging, and promote the relevance of composition in their own lives. Rather than a healing pedagogy, my last chapter offers a trauma-informed and student-informed care pedagogy that aims to support the wellness of students while sustaining ourselves.
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ItemIMMUNOMODULATORY ACTIVITY OF SYNTHETIC AURONE DERIVATIVES, AZAAURONES, IN LPS-STIMULATED RAW 246.7 MACROPHAGE-LIKE CELLS(Middle Tennessee State University, 2024)Inflammation, a fundamental biological response, is essential for various physiological processes. However, dysregulated or chronic inflammation is linked to numerous pathological conditions. This thesis delves into the unexplored realm of azaaurone derivatives, nitrogen-substituted versions of aurones, investigating their potential as anti-inflammatory agents. The research comprises two distinct chapters, each shedding light on different facets of the anti-inflammatory properties of azaaurones. In the first experiment, titled "Evaluation of Twenty-Seven Azaaurone Derivatives as Potential Anti-Inflammatory Agents," a screening of 27 azaaurones for cytotoxicity in RAW 264.7 cells, a murine macrophage-like cell model, was conducted. Four promising derivatives (AAA2Me, AAA3Br, AAAPh and AAA3Me) were identified as showing minimal cytotoxicity. Subsequent treatments of the macrophage-like cells demonstrated a dose-dependent reduction in nitrite production, with AAAPh and AAA3Me exhibiting notable inhibitory effects. Importantly, azaaurones displayed anti-inflammatory potential at concentrations approximately 40 times lower than aurones, highlighting their considerable bioactivity. In the second experiment, titled "The Effects of the Synthetic Azaaurone (Z)-1-Acetyl-2- Benzylideneindolin-3-one on iNOS, NF-κB, and MAPK Pathways in LPS-Stimulated RAW 264.7 Cells," the focus shifted to (Z)-1-Acetyl-2-Benzylideneindolin-3-one and its derivatives. The study assessed iNOS protein expression, NF-κB and MAPK pathway activation, and TNF-α secretion in LPS-stimulated RAW 264.7 cells. While azaaurones did not significantly reduce iNOS protein expression, they demonstrated promising effects on inflammation-associated signaling pathways. Notably, AAA2Me showed a significant reduction in p38 protein expression, indicating a potential mechanism of action. Additionally, a trend towards decreased pp38 and reduced TNF-α secretion by multiple derivatives further supports their anti-inflammatory efficacy. These findings collectively underscore the considerable anti-inflammatory potential of azaaurone derivatives, positioning them as promising candidates for further drug development. The significant inhibition observed at low concentrations, coupled with insights into their molecular interactions and impact on key signaling pathways, provides a solid foundation for future research and therapeutic applications targeting inflammatory responses. The potential of azaaurones to address chronic inflammation and associated diseases opens up new possibilities for advancing drug discovery and improving clinical outcomes.
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ItemSynthesis and study of the dyeing properties of aurones and development of a visible light-mediated polyene cyclization methodology(Middle Tennessee State University, 2024)Aurones are primarily responsible for pigmentation, imparting yellow and orange hues to flowers and fruits. Despite their proven coloring role in nature, other applications of their pigmentation and photophysical properties have been limited and focused almost entirely on their fluorescent properties. To address this gap, two different color-related projects were explored in this dissertation. In one project, different dimethyl amino- and ferrocene-appended hydroxy and methoxy substituted aurone derivatives were screened for their dyeing potential using an environmentally sustainable deep eutectic solvent of choline chloride and urea (chapter II). Considering various factors, including solubility, accessibility of the aurones, and their color-imparting ability to different fabrics, only four hydroxy derivatives of dimethylamino-aurones 22-25 were selected for further study. Their dye exhaustion ability, color fastness, color strength, and fixation property on wool fabric were studied. Among the four aurones, 6-OH-DMAA (22) showed the highest dye exhaustion, whereas 6,7-diOH-DMAA (25) dyed wool showed the lowest value. In qualitative grey-scale tests, all four aurones showed excellent color fastness against rub, wash, and light exposure, revealing their promising dyeing ability. The color strength (K/S) were calculated using the reflectance values of the dyed fabrics. Fabrics dyed with aurone 22 exhibited high reflectance overall, showing low K/S value for all four tests. Aurones 23 and 25 dyed fabrics showed comparable K/S against rub, wash, and light tests. Wool fabric dyed with 24 (4,6-diOH-DMAA) showed consistently high K/S for the tests. The other study sought to employ the aurone scaffold as a versatile organic photocatalyst, looking initially at polyene cyclizations (chapter III). Polyene cyclizations allow easy excess to complex polycyclic molecules from acyclic precursors through stereo-controlled multiple C-C bond formation. While this transformation has been used frequently over the years, existing strategies largely demand the use of expensive and toxic transition metal complexes to accomplish the desired reaction. In a highly unusual result, it was discovered that the use of a blue LED enabled a completely catalyst-free cascade cyclization of geranyl phenols containing bromo- and chloro- groups at different positions of the phenolic ring. The desired cyclization products were obtained with high stereoselectivity in the hexafluoro-2-propanol reaction medium. This reaction condition is the simplest option yet reported and has potential for future extension to additional catalyst-free photochemical transformations.