Digital Commons Network^™

Evaluation Of Cultivar Susceptibility And In-Furrow Fungicide Efficacy For Management Of Southern Blight Of Soybean, Adam Joseph Connor

Theses and Dissertations

Southern Blight (SB), caused by the fungus Athelia rolfsii, has increasingly impacted Mississippi soybean production with estimated economic losses in recent years rising from $181,616 in 2016 to $9,508,412 in 2021. Currently, there are no recommended fungicides and no known commercially available cultivar resistance. Eleven cultivars were evaluated for their response to the presence of Athelia rolfsii in the 2021 field trial. An in vitro fungicide assay was conducted to evaluate the efficacy of five fungicides to determine the respective EC50. These fungicides were then evaluated in combination with three cultivars, one mild, one moderate, and one severe in the …

Adaptive Traction, Power And Torque Control Strategies And Optimization In An All-Electric Powertrain, Aymane Hidara

Theses and Dissertations

Electric and hybrid-electric vehicles lean heavily on intricate control algorithms to provide smooth, reliable, and secure operations under any driving conditions. Three distinct supervisory control strategies have been developed, each aiming to improve reliability and vehicle performance of a dual-motor electric vehicle equipped with an all-wheel-drive, fully electric powertrain. These algorithms are adept at dynamically modulating and constraining the torque provided to the wheels, leveraging two autonomous permanent magnet electric drive units. This study utilizes a vehicle model jointly provided by MathWorks and General Motors in partnership with industry sponsors. The these strategies were implemented in the model and enhanced …

Safety-Aware Autonomous Robot Navigation, Mapping And Control By Optimization Techniques, Tingjun Lei

Theses and Dissertations

The realm of autonomous robotics has seen impressive advancements in recent years, with robots taking on essential roles in various sectors, including disaster response, environmental monitoring, agriculture, and healthcare. As these highly intelligent machines continue to integrate into our daily lives, the pressing imperative is to elevate and refine their performance, enabling them to adeptly manage complex tasks with remarkable efficiency, adaptability, and keen decision-making abilities, all while prioritizing safety-aware navigation, mapping, and control systems. Ensuring the safety-awareness of these robotic systems is of paramount importance in their development and deployment. In this research, bio-inspired neural networks, nature-inspired intelligence, deep …

Designing An Artificial Immune Inspired Intrusion Detection System, William Hosier Anderson

Theses and Dissertations

The domain of Intrusion Detection Systems (IDS) has witnessed growing interest in recent years due to the escalating threats posed by cyberattacks. As Internet of Things (IoT) becomes increasingly integrated into our every day lives, we widen our attack surface and expose more of our personal lives to risk. In the same way the Human Immune System (HIS) safeguards our physical self, a similar solution is needed to safeguard our digital self. This thesis presents the Artificial Immune inspired Intrusion Detection System (AIS-IDS), an IDS modeled after the HIS. This thesis proposes an architecture for AIS-IDS, instantiates an AIS-IDS model …

Identifying The Shortest Log Trucking Routes And Optimizing Those Constrained By Low-Weight Bridges In Mississippi, Swagat Attreya

Theses and Dissertations

Timber haulage in Mississippi incurs the greatest portion of logging expenses because of a myriad of closed and posted (restricted) bridges. This study utilized Dijkstra's algorithm method in ArcGIS Pro to derive 129 feasible shortest optimal trucking routes between 46 harvest sites and 32 softwood sawmills in Mississippi. Among these routes, 30 of them had restricted bridges along the way; however, only 13 viable alternative routes were identified due to distance and weight restrictions. The additional trucking distance for alternative routes ranged between 1.5 to 12.9 miles, whose effect on transportation cost was determined using a Mixed Integer Linear Programming …

Quantum Computers For Nuclear Physics, Muhammad F. Yusf

Theses and Dissertations

We explore the paradigm shift in quantum computing and quantum information science, emphasizing the synergy between hardware advancements and algorithm development. Only now have the recent advances in quantum computing hardware, despite a century of quantum mechanics, unveiled untapped potential, requiring innovative algorithms for full utilization. Project 1 addresses quantum applications in radiative reactions, overcoming challenges in many-fermion physics due to imaginary time evolution, stochastic methods like Monte Carlo simulations, and the associated sign problem. The methodology introduces the Electromagnetic Transition System and a general two-level system for computing radiative capture reactions. Project 2 utilizes Variational Quantum Eigensolver (VQE) to …

Investigation And Control Of Görtler Vortices In High-Speed Flows, Omar Es-Sahli

Theses and Dissertations

High-amplitude freestream turbulence and surface roughness elements can excite a laminar boundary-layer flow sufficiently enough to cause streamwise-oriented vortices to develop. These vortices resemble elongated streaks having alternate spanwise variations of the streamwise velocity. Following the transient growth phase, the fully developed vortex structures downstream undergo an inviscid secondary instability mechanism and, ultimately, transition to turbulence. This mechanism becomes much more complicated in high-speed boundary layer flows due to compressibility and thermal effects, which become more significant for higher Mach numbers. In this research, we formulate and test an optimal control algorithm to suppress the growth rate of the aforementioned …

Neural Networks For Improved Signal Source Enumeration And Localization With Unsteered Antenna Arrays, John T. Rogers Ii

Theses and Dissertations

Direction of Arrival estimation using unsteered antenna arrays, unlike mechanically scanned or phased arrays, requires complex algorithms which perform poorly with small aperture arrays or without a large number of observations, or snapshots. In general, these algorithms compute a sample covriance matrix to obtain the direction of arrival and some require a prior estimate of the number of signal sources. Herein, artificial neural network architectures are proposed which demonstrate improved estimation of the number of signal sources, the true signal covariance matrix, and the direction of arrival. The proposed number of source estimation network demonstrates robust performance in the case …

Characterization Of Isomeric States In Neutron-Rich Nuclei Approaching N = 28, Timilehin Hezekiah Ogunbeku

Theses and Dissertations

The investigation of isomeric states in neutron-rich nuclei provides useful insights into the underlying nuclear configurations, and understanding their occurrence along an isotopic chain can inform about shell evolution. Recent studies on neutron-rich Si isotopes near the magic number N = 20 and approaching N = 28 have revealed the presence of low-lying states with intruder configurations, resulting from multiple-particle, multiple-hole excitations across closed shell gaps. The characterization of these states involves measuring their half-lives and transition probabilities.

In this study, a new low-energy (7/2⁻₁) isomer at 68 keV in ³⁷Si was accessed via beta decay …

Flood Inundation Mapping Of The Catalpa Creek Watershed, Subodh Poudel

Theses and Dissertations

This study addresses flood risk assessment in the Catalpa Creek watershed, located in northeast Mississippi, USA. Employing the Hydrological Modeling System (HEC-HMS) and the River Analysis System (HEC-RAS), integrated models were developed and calibrated, to predict flood behavior within the watershed. The study conducted flood frequency analyses for return periods ranging from 2 to 100 years and generated flood inundation maps, pinpointing flood-prone areas. Mitigation measures for flood risk management were recommended. The results underscore the effectiveness of the integrated modeling approach for simulating and understanding the complex dynamics of flood events. The research identified critical flood-prone zones, emphasizing the …

Scalable And Explainable Self-Supervised Motif Discovery In Temporal Data, Somayeh Bakhtiari Ramezani

Theses and Dissertations

The availability of a scalable and explainable rule extraction technique via motif discovery is crucial for identifying the health states of a system. Such a technique can enable the creation of a repository of normal and abnormal states of the system and identify the system’s state as we receive data. In complex systems such as ECG, each activity session can consist of a long sequence of motifs that form different global structures. As a result, applying machine learning algorithms without first identifying the local patterns is not feasible and would result in low performance. Thus, extracting unique local motifs and …

Membrane Fabrication And Functionalization For Improved Removal Of Monovalent Ions From Water Using Electrodialysis, Matthew P. Sheorn

Theses and Dissertations

Electrodialysis is a membrane separation process that uses an electrical potential to drive the separation. The performance of these systems is largely based on the performance of their ion exchange membranes (IEMs). This research focused on enhancing the performance of IEMs for electrodialysis through surface modification techniques involving chitosan bonded to the surface of commercially available cation exchange membranes (CEMs). The surface functionalization techniques resulted in membranes with improved electrodialysis performance. This research also explored the processing framework to produce functionalized sulfonated PEEK (sPEEK) nanofibers for future consideration as cation exchange membranes.

Chitin was deacetylated to form the functionalized biopolymer …

Visual Acquisition And Detection Of Manned Fixed-Wing Aircraft And Rotorcraft: An Analysis Of Pilots' Perception And Performance, Rania Bassou

Theses and Dissertations

In recent years, the rapid advancement of Unmanned Aircraft Systems (UAS) has led to an increasingly complex National Airspace System (NAS), necessitating a comprehensive understanding of factors that impact pilot visual acquisition and detection of other aircraft (including manned fixed-wing, rotorcraft, and UAS). The objective of this study is to investigate factors that affect pilot performance in visually acquiring and detecting other manned-fixed wing aircraft and manned rotorcraft using a multi-method approach, incorporating qualitative and quantitative data analysis. A diverse sample of pilots with varying flight experience participated in the study. Participants were exposed to a series of flight test …

Effects Of Electrical Stimulation On Water-Soluble Flavor Compounds In Beef Semimembranosus Muscle, Chelsie Beebe

Theses and Dissertations

This study examined the effects of electrical stimulation on water-soluble flavor compounds in beef semimembranosus muscle, collected immediately after exsanguination (PRE), immediately after stimulation (POST), and 24 h postmortem (H24) from both stimulated (ES) and non-stimulated (CON) carcasses. Short-chained peptides were greater in ES at H24 (P = 0.007). Glutamic acid concentration was above its taste threshold (0.044 mmol/kg) and was less in ES at PRE and POST by 0.030 mmol/kg (P ≤ 0.028) but was similar in both ES and CON by H24 (P = 0.142). Lysine, a Strecker amino acid, was greater in ES at H24 by 0.138 …

The Cost Of Voting Categorized: A Comprehensive Review, Landon Brady

Theses and Dissertations

The primary purpose of this paper is to analyze the research field of cost of voting and review the relevant literature on voter participation. After reviewing the literature, a development of a theoretical framework to categorize multiple variables associated with the cost of voting will be completed. The goal is to create clear, concise, and simple categories that define the cost of voting. This should add conceptual clarity to the field by linking variables into a common foundation. The research also connects the sociological and psychological category of intrapersonal to concepts of social group needs, sense of achieving a greater …

Examining The Impact That A Modified School Calendar Had On Teacher Attendance In A Rural Mississippi School District, James W. Carlisle Jr.

Theses and Dissertations

Educational leaders have long recognized the certified classroom teacher as the most important factor in student performance and success. In his research article Teachers Matter: Understanding Teachers’ Impact on Student Achievement for the Rand Corporation, Opper (2019) stated, “When it comes to student performance on reading and math tests, teachers are estimated to have two to three times the effect of any other school factor, including services, facilities, and leadership” (para. 2). While district and school administrators certainly understand the impact teachers have on student performance, little has been done to mitigate the issue of teacher absenteeism, which has become …

The Impact Of Prior Pandemic Planning On Health Outcomes During The Covid-19 Pandemic: A Study Of Local Government Pandemic Planning In The United States, Karissa D. Bergene

Theses and Dissertations

In late 2019, scientists discovered a novel strain of coronavirus originating out of Wuhan, China. By January 2020, the United States (U.S.) saw its first positive case of coronavirus and the public was still unsure how serious of an epidemic this would be. By the time the World Health Organization declared the novel coronavirus disease (COVID-19) epidemic a “global pandemic” on March 11, 2020, world leaders, public health experts, scientists, and public administrators kicked into high gear to start serious pandemic response efforts. The public sector is typically the responsible authority for the preparedness, response, mitigation, and recovery of such …

Stream Water Quality Under Baseflow Conditions In A Livestock Production Area, Maryi Lorena Chavarro Chaux

Theses and Dissertations

This study evaluates the spatial and temporal impacts of implemented Best Management Practices (BMP) on stream water quality under baseflow conditions in a stream segment affected by livestock production. The BMPs includes 10-m fenced riparian zone and crossing paths along the reach segment. Grab water samples and water quality monitoring were collected biweekly from July 2019 to March 2022. Water quality parameters included temperature, dissolved oxygen, electric conductance, total dissolved solids, turbidity, and pH. Water samples were lab analyzed for sediments and nutrients. Results evidenced poor water quality before BMPs implementation, with nutrient concentrations exceeding the nation's and state's criteria. …

Advancing Air Filtration Analysis: A Comprehensive Approach To Particle Loading Models, Gentry Nathaniel Berry

Theses and Dissertations

Fibrous air filters are commonly used to capture airborne particles due to their potential for a relatively high capture efficiency and low airflow resistance. Their performance characteristics make them ideal candidates in many instances, spanning a wide range from residential to sensitive industrial applications. However, as more particles are captured, the performance of the filter will evolve. This evolution of performance typically manifests as a higher capture efficiency and higher airflow resistance resulting from the additional particulate deposits. The prediction of fibrous filter performance has been the focus of research for many decades, resulting in numerous analytical, numerical, and empirical …

Advancing Salamander Conservation Efforts In Zoos And Aquaria Through Assisted Reproductive Technologies (Art), Devin Marie Chen

Theses and Dissertations

Salamanders are one of the most at-risk taxa in the world due to habitat destruction, pollution, climate change, invasive diseases, and more. This has led to a need for conservation breeding programs that are often associated with zoos and aquaria. Salamanders can be difficult to breed in captivity, though, due to their dependence on specific environmental cues and other unknown factors that stimulate sperm and egg production. To overcome these challenges, assisted reproductive technologies (ART) such as exogenous hormone administration, sperm cryopreservation, and in-vitro fertilization have been developed to increase offspring propagation and maintain genetic diversity. If genetically robust populations …

We Built This Country For Free – Using A Phenomenological Approach For (Re) Imagining Mississippi Black Small-Scale Farmers, Destiny Denise Crockett

Theses and Dissertations

By the early 20th century, in 1920, Black farmers owned 14% of US farmland. Today, in the 21st century, Black farmers own less than 2% of US farmland. The demise of Black farmers and Black farmland in US Agriculture is a direct result of social, political, and racial weaponization against their foodways, culture, and livelihoods. The history concerning the plight of Black farmers goes beyond USDA's historical discrimination but enters a position where racism is embedded and perpetuated within the structure of US agriculture. In effect, Black small-scale farmers have reaped the downfall of this system, enduring racial biases and …

A Conceptual Decentralized Identity Solution For State Government, Martin Duclos

Theses and Dissertations

In recent years, state governments, exemplified by Mississippi, have significantly expanded their online service offerings to reduce costs and improve efficiency. However, this shift has led to challenges in managing digital identities effectively, with multiple fragmented solutions in use. This paper proposes a Self-Sovereign Identity (SSI) framework based on distributed ledger technology. SSI grants individuals control over their digital identities, enhancing privacy and security without relying on a centralized authority. The contributions of this research include increased efficiency, improved privacy and security, enhanced user satisfaction, and reduced costs in state government digital identity management. The paper provides background on digital …

“I Tell It Like It Is, Then How It Could Be”: Public Discourse And Public Administration In Popular American Music Since The 1990s, Kristen Dechert

Theses and Dissertations

This study is an analysis of lyrics from popular American music albums since the 1990s to understand public discourse about and experience with public administration. Albums included in the study came from two prominent sources: Billboard and Pitchfork decade-end lists. The study is framed by critical, postmodern, and responsiveness theories, methodologically grounded in critical discourse analysis, and technically approached using standard qualitative methods, including especially qualitative content analysis and iterative, inductive coding techniques. Findings from the qualitative study demonstrate public discourse on the themes of institutional and systemic racism and violence within and perpetuated by public administration and public institutions. …

Factors In Depopulation Trends Among Young Adults In Rural Areas In Mississippi, Katherine H. Ellard

Theses and Dissertations

The purpose of this study was to determine why young adults are leaving rural Mississippi towns and not returning to those areas. Research objectives were to 1) describe the characteristics of young adults who have left rural areas in the last ten years , 2) identify specific reasons why young adults choose to leave where they were raised, and 3) identify factors that would attract young people to return to rural areas in Mississippi.

Findings from this study indicated young adults were leaving rural areas for better educational and job opportunities, but some were relocating to other areas within Mississippi …

The Influence Of At-Planting Insecticide Treatments On Tobacco Thrips, (Thysanoptera:Thripidae), And Reniform Nematode, (Tylenchida:Hoplolaimidae), In Conventional And Thryvon Cotton Systems, Walker Brett Farmer

Theses and Dissertations

One of the objectives of this research was to evaluate the need for an additional imidacloprid seed treatment on ThryvOn^® (Bayer Crop Science^®, St. Louis, MO) cotton to effectively manage tobacco thrips, Frankliniella fusca (Hinds). While evaluating thrips densities and damage ratings, ThryvOn cotton continued to display reduced damage and thrips populations than non-ThryvOn. Thrips populations and damage ratings were consistently reduced when incorporating a higher rate of imidacloprid, but they were not reduced enough to justify the higher rates of imidacloprid. Another objective of this research was to evaluate the impact of aldicarb (AgLogic Chemical^{® …}

Improved Methodology For Conducted Emi Assessment Of Power Electronics And Line Impedance Measurement, Mark Anthony Didat

Theses and Dissertations

Electromagnetic Interference (EMI), primarily common mode (CM), is problematic in a wide range of electronic circuits due to its propensity to radiate, particularly in high power applications. It is routine for much effort and resources to be dedicated to its characterization and reduction as EMI compliance is a requirement for most electronic systems and devices, including power electronics. Many well-known factors contribute to a system’s EMI performance including intentional coupling from system components as well as unintentional coupling from parasitics. Sources of intentional coupling may include Y-capacitors intended to mitigate EMI as part of a filter. Unintentional coupling is more …

Does Mississippi School Principals’ Age, Race, Gender, Educational Attainment, Work Experience In Education, Or Evaluation Scores Influence Accountability Points?, Braxton Dywayne Stowe

Theses and Dissertations

Traditional research agrees that only effective school principals can fully influence student achievement, and school leaders are pivotal to the success of schools in America. Researchers have linked positive student outcomes to further illustrate the point, including student achievement, to high-quality school leadership. The purpose of this study is to assist state and district education leaders in Mississippi in having a more profound knowledge of which principal demographics and characteristics are more directly correlated with the improvement of accountability scores or student achievement. The results of the correlational and regression analysis to determine the relationship between principal variables and the …

Design, Development, And Validation Of A Perfusion-Compression Bioreactor To Study Osteogenesis In Bone Explants, Alexis Victoria Graham

Theses and Dissertations

The current gold standard treatment for bone defects is autologous cancellous bone graft, which involves increased surgery time and donor site morbidity, and limited supply of bone and cells for regeneration. Bioreactors may aid in the generation of mechanically conditioned bone grafts with more cells compared to traditional grafts. However, the specific parameters of fluid flow and mechanical loading which contribute to osteogenesis and cell viability in bioreactors are not fully characterized. Here, a perfusion-compression bioreactor system was developed to study osteogenesis in porcine trabecular bone explants. Loading accuracy was over 88% across six bioreactors at a 0.1 s-1 strain …

Geospatial Integrated Urban Flood Mapping And Vulnerability Assessment, Md Tazmul Islam, Md Tazmul Islam

Theses and Dissertations

Natural disasters like flooding have always been a big problem for countries around the world, but as the global climate changes and the number of people living in cities keeps growing, the threat of flooding has become a lot worse. Even though many studies have been conducted on flood mapping and vulnerability assessment in urban areas, this research addresses a significant knowledge gap in this domain. First, we used a flood depth estimation approach has been used to address the overestimation of urban flood mapping areas using Sentinel-1 images. Ten different combinations of the two initial VH and VV polarizations …

The Migration Ecology Of North American Turkey Vultures Wintering In The Neotropics: Spatial And Population Dynamics, Adrián José Naveda-Rodríguez

Theses and Dissertations

The spatial and population dynamics of avian scavengers are poorly understood. This information is key for management and conservation interventions that guarantee long-term species conservation. My goal in this dissertation is to fill information gaps on the movement ecology of New World vultures using the Turkey Vulture (Cathartes aura) as a model species. I used a continental-wide satellite telemetry dataset to study the migration ecology, space-use, and demography of the three North American breeding populations of Turkey Vultures wintering in the Neotropics during a 17-year period. I found that primary productivity, but not weather, triggered Turkey Vulture migratory …