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Full-Text Articles in Engineering

Automated Intake Valve Control Systems For Rural Community Water System, Isabelle Hamby, Jackson Reeves, Ashlyn Celichowski, Elizabeth Morgan May 2024

Automated Intake Valve Control Systems For Rural Community Water System, Isabelle Hamby, Jackson Reeves, Ashlyn Celichowski, Elizabeth Morgan

Chancellor’s Honors Program Projects

No abstract provided.


The Role Of Grain Morphology And Individual Grain Fracture On Granular Material Behavior, Anne Katherine Turner May 2024

The Role Of Grain Morphology And Individual Grain Fracture On Granular Material Behavior, Anne Katherine Turner

Doctoral Dissertations

Granular materials, such as sand, are multi-scale materials combining an immense number of crushable particles to create an assembly. Numerical approaches to modeling sand’s mechanical behavior often use simplifications, such as treating the volume as a continuum or representing the particles with rigid, idealized spheres using the discrete element method. These approaches overlook crucial nonlinear phenomena, such as individual grain morphology and fracture, which have been shown to influence sand’s strength and plasticity behavior. This research investigated methods to incorporate such phenomena , focusing on simulating single grain crushing tests and 1D confined compression of Ottawa sand using finite element …


Controlling Complex Dynamic Transportation Systems: Development And Adaptation Of A Novel Distributed Cooperative Multi-Agent Learning Technique, Russell Thomas Graves May 2024

Controlling Complex Dynamic Transportation Systems: Development And Adaptation Of A Novel Distributed Cooperative Multi-Agent Learning Technique, Russell Thomas Graves

Doctoral Dissertations

Intelligent transportation systems continue to increase complexity, scale, and scope as more devices contain embedded compute. Cooperation among vehicles, intersections, and other members of the greater traffic ecosystem at a system-of-systems level is critical to improving the efficiency of the multi-billion-dollar asset that is the U.S. roadway infrastructure. This work introduces a negotiations strategy among multi-agent reinforcement learning agents and applies this to both traffic signal control and supervisory control of vehicle platooning. The traffic signal control implementation builds off of many prior research thrusts, and was shown to improve vehicle throughput by an average of 671veh/hr over actuated traffic …


Urban Ecohydrology And The Watershed Microbial Continuum, Victoria C. Rexhausen May 2024

Urban Ecohydrology And The Watershed Microbial Continuum, Victoria C. Rexhausen

Doctoral Dissertations

A rapidly urbanizing world is adding unprecedented stress to water resources. Urbanization results in high rates of stream impairment, including but not limited to ecological stress, pollution, and flooding. A fully integrated and holistic perspective is necessary for effective remediation strategies for these wicked problems. This monitoring study from a heterogeneous urban watershed investigated the geospatial and seasonal interactions between urban hydrology and biological processes using stable isotope compositions, anions, and microbial.

This research found that nitrate concentrations in an urban watershed were ecologically driven. NO3- concentrations ranged from 0.4 to 12.7 mg/L throughout the watershed. Nitrate concentrations …


Integrated Approaches In Wastewater Surveillance Of Sars-Cov-2: Monitoring, Persistence, Sampling Optimization, And Impacts On Microbial Community Structure, Ye Li May 2024

Integrated Approaches In Wastewater Surveillance Of Sars-Cov-2: Monitoring, Persistence, Sampling Optimization, And Impacts On Microbial Community Structure, Ye Li

Doctoral Dissertations

Wastewater-based epidemiology (WBE) serves as a crucial tool for monitoring SARS-CoV-2 prevalence on university campuses, yet concerns persist regarding its effectiveness as an early warning system for COVID-19 outbreaks. This study aimed to address these concerns through a comprehensive field trial conducted at the University of Tennessee, Knoxville. We investigated correlations between SARS-CoV-2 concentrations, both with and without normalization using Pepper Mild Mottle Virus (PMMoV), and various parameters. Significant positive correlations were observed between SARS-CoV-2 concentrations and active cases in the weeks prior to, during, and following the monitoring period, unaffected by PMMoV normalization. Concurrently, the persistence of SARS-CoV-2 RNA …


Validating The Design Tensile Strength Of Grade 5 And Metric Class 8.8 Bolts, Paxton Charles Lifsey May 2024

Validating The Design Tensile Strength Of Grade 5 And Metric Class 8.8 Bolts, Paxton Charles Lifsey

Masters Theses

Bolted connections offer many benefits including ease of installation and maintenance and replaceable components, but must have sufficient strength in order to take advantage of these benefits. One of the major ways a bolted connection is loaded is under tension. In this loading condition, bolted connections can fail via tension in the threaded area, shear in the bolt threads, or shear in the nut threads. Standards such as FED-STD-H28/2B and ISO TR/16224 include equations for the stress area and strength of these limit states as well as for the required length of engagement such that tensile failure controls. These equations …


An Audio-Based Emotion Monitoring System For Enhancing Construction Worker Safety, Mengjun Wang May 2024

An Audio-Based Emotion Monitoring System For Enhancing Construction Worker Safety, Mengjun Wang

Masters Theses

The high suicide rate among construction workers in the U.S. is a concerning issue. For every 100,000 workers in this field, 53.3 are reported to commit suicide, compared to the national average of 12.93. This statistic highlights the importance of addressing the mental well-being of construction workers, which directly impacts their performance and safety on the job. In this research, an audio-based system is proposed to monitor the emotions of construction workers in real-time, aiming to enhance their safety and address potential concerns proactively. The system involves a novel stimulus mechanism that encourages workers to interact with an AI, which …


Enhanced Bioretention Modeling At The Catchment-Scale: An Integrated Drainmod-Urban And Swmm Approach, Ghada Diab Dec 2023

Enhanced Bioretention Modeling At The Catchment-Scale: An Integrated Drainmod-Urban And Swmm Approach, Ghada Diab

Doctoral Dissertations

Bioretention systems are increasingly being adopted in stormwater management as an effective measure to promote infiltration and restore more natural hydrology in urbanized watersheds. Given the significant financial investment in these practices, reliable bioretention models are necessary to predict the effectiveness of these practices prior to installation. One such model, DRAINMOD-Urban (DM-Urban), was recently developed to produce hydrographs with a high temporal resolution at the site-scale, showing substantial promise during initial testing. However, the dataset used for initial testing was limited, consisting of one bioretention area with minimal occasions of overflow. Additionally, DM-Urban is an input-heavy model and there is …


Transportation System Performance And Traveler Behavior In The Context Of A Systemwide Shock: Applications Of Data Science Toward A Sustainable Future, A. Latif Patwary Dec 2023

Transportation System Performance And Traveler Behavior In The Context Of A Systemwide Shock: Applications Of Data Science Toward A Sustainable Future, A. Latif Patwary

Doctoral Dissertations

The COVID-19 pandemic, a systemwide shock, has left a long-lasting and significant impact on transportation systems. It has contributed to a shift in travel behavior, with many people turning to work from home (WFH) and online shopping. This shift has led to a reduction in vehicular travel. However, the pandemic witnessed increased crash fatalities despite a reduction in overall crashes, disproportionately affecting disadvantaged communities (DACs). The main question arising from these pandemic-related issues is what we can learn to improve transportation systems and shape future travel behavior. Therefore, this dissertation aims to investigate how the transportation system changed during COVID-19 …


Exploring Soil Microbial Dynamics In Southern Appalachian Forests: A Systems Biology Approach To Prescribed Fire Impacts, Saad Abd Ar Rafie Dec 2023

Exploring Soil Microbial Dynamics In Southern Appalachian Forests: A Systems Biology Approach To Prescribed Fire Impacts, Saad Abd Ar Rafie

Doctoral Dissertations

Prescribed fires in Southern Appalachian forests are vital in ecosystem management and wildfire risk mitigation. However, understanding the intricate dynamics between these fires, soil microbial communities, and overall ecosystem health remains challenging. This dissertation addresses this knowledge gap by exploring selected aspects of this complex relationship across three interconnected chapters.

The first chapter investigates the immediate effects of prescribed fires on soil microbial communities. It reveals subtle shifts in porewater chemistry and significant increases in microbial species richness. These findings offer valuable insights into the interplay between soil properties and microbial responses during the early stages following a prescribed fire. …


3d Experimental Studies Of Temperature And Crystallographic Effects On Creep And Strength In Rock Salt, Amirsalar Moslehy Dec 2023

3d Experimental Studies Of Temperature And Crystallographic Effects On Creep And Strength In Rock Salt, Amirsalar Moslehy

Doctoral Dissertations

Salt domes utilization as storage reservoirs in the energy sector has led to extensive studies on rock salt’s mechanical and geothermal behavior. These important facilities’ safety and serviceability rely on understanding rock salt’s compressive strength and creep behavior under various loading directions, water contents, in-situ stresses, and temperatures. Despite numerous studies on rock salt’s mechanical behavior in the literature, there are still many unanswered questions about rock salt’s behavior. This dissertation was aimed at utilizing state-of-the-art experimental techniques such as 3D synchrotron micro-computed tomography (SMT) and 3D x-ray diffraction (3DXRD) along with hundreds of compression and creep experiments to enhance …


Effect Of Seawater And Temperature Upon Carbon Fiber/Vinyl Ester (Cfve) Composites And Its Constituents, Vivek Chawla Dec 2023

Effect Of Seawater And Temperature Upon Carbon Fiber/Vinyl Ester (Cfve) Composites And Its Constituents, Vivek Chawla

Doctoral Dissertations

An experimental and computational investigation has been carried out to: (1) develop micromechanical characterization techniques for polymeric composites and (2) evaluate the effects of seawater and temperature upon the micro- and macro-response of the carbon fiber vinyl ester composites (CF/VE). Compression properties degradation due to short-term and long-term exposure to seawater is evaluated. A 12-16 % reduction in compression strength is observed due to long-term exposure to seawater, which is attributed to a decrease in interfacial shear strength (IFSS) due to long-term exposure to seawater. The developed Push-out methodology is used to characterize the IFSS. The presented approach consistently yields …


Functional Cementitious Composites With Micro-Sized Particulate Fillers For Additive Construction And Energy-Efficient Buildings, Adam Brooks Dec 2023

Functional Cementitious Composites With Micro-Sized Particulate Fillers For Additive Construction And Energy-Efficient Buildings, Adam Brooks

Doctoral Dissertations

With a growing energy demand, the development of sustainable and energy efficient building materials is growing rapidly. Numerous researches have focused on low carbon footprint construction materials, high-performance thermal insulations, high-performance façade, and thermal energy storage. Among these, the development of functional cementitious composites has attracted significant attention due to its potential utilities in building energy reduction and decarbonatization efforts. For example, fly ash cenospheres have been used as micro-size lightweight fillers to achieve low density and thermal conductivity. The use of phase change materials (PCM) in concrete has been studied to answer energy demands. While their inclusion into concrete …


Modular Composite Sandwich Structures For Thermal And Structural Retrofitting Of Existing Buildings, Marc Al Ghazal Dec 2023

Modular Composite Sandwich Structures For Thermal And Structural Retrofitting Of Existing Buildings, Marc Al Ghazal

Masters Theses

Around 40% of global energy consumption and 30% of worldwide carbon dioxide (CO2) emissions are attributed to buildings. Most of this consumption is dedicated to ensuring thermal comfort. The goal of this research was to develop and field validate retrofit solutions to improve the energy efficiency of buildings. Exterior cladding panels were designed and tested to ensure adequate thermal and structural performance. Sandwich panels (glass fibers reinforced polymer (GFRP) skins and polymeric foam cores) were fabricated using the vacuum assisted resin transfer molding (VARTM) process. Extruded polystyrene (XPS) and polyurethane (PU) foams were compared as core materials through a series …


Integrated Modeling And Monitoring For A Healthy And Sustainable Building Environment, Yifang Xu Aug 2023

Integrated Modeling And Monitoring For A Healthy And Sustainable Building Environment, Yifang Xu

Doctoral Dissertations

The transmission of airborne diseases indoors is a significant challenge to public health. Buildings are hotspots for viral transmission, which can result in adverse effects on human health and quality of life, especially considering that individuals spend approximately 87% of their time indoors. The emergence of the COVID-19 pandemic has highlighted the importance of considering health aspects during the development of sustainable built environments. Consequently, maintaining a healthy, sustainable, and comfortable built environment represents a major challenge for facilities management teams. However, research on the infection risks associated with emerging pandemics is still in its infancy, and the effectiveness of …


Responsive Building Envelope For Grid-Interactive Efficient Buildings – Thermal Performance And Control, Yawen He Aug 2023

Responsive Building Envelope For Grid-Interactive Efficient Buildings – Thermal Performance And Control, Yawen He

Doctoral Dissertations

The building sector accounts for 30% of total energy consumption worldwide. Responsive building envelopes (or RBEs) are one of the approaches to achieving net-zero energy and grid-interactive efficient buildings. However, research and development of RBEs are still in the early stages of technologies, simulation, control, and design. The control strategies in prior studies did not fully explore the potential of RBEs or they obtained good performance with high design and deployment costs. A low-cost strategy that does not require knowledge of complex systems is needed, while no studies have investigated online implementations of model-free control approaches for RBEs. To address …


Improving Mobility And Safety In Traditional And Intelligent Transportation Systems Using Computational And Mathematical Modeling, Shahrbanoo Rezaei Aug 2023

Improving Mobility And Safety In Traditional And Intelligent Transportation Systems Using Computational And Mathematical Modeling, Shahrbanoo Rezaei

Doctoral Dissertations

In traditional transportation systems, park-and-ride (P&R) facilities have been introduced to mitigate the congestion problems and improve mobility. This study in the second chapter, develops a framework that integrates a demand model and an optimization model to study the optimal placement of P&R facilities. The results suggest that the optimal placement of P&R facilities has the potential to improve network performance, and reduce emission and vehicle kilometer traveled. In intelligent transportation systems, autonomous vehicles are expected to bring smart mobility to transportation systems, reduce traffic congestion, and improve safety of drivers and passengers by eliminating human errors. The safe operation …


Advanced Air Quality Management With Machine Learning, Cheng-Pin Kuo May 2023

Advanced Air Quality Management With Machine Learning, Cheng-Pin Kuo

Doctoral Dissertations

Air pollution has been a significant health risk factor at a regional and global scale. Although the present method can provide assessment indices like exposure risks or air pollutant concentrations for air quality management, the modeling estimations still remain non-negligible bias which could deviate from reality and limit the effectiveness of emission control strategies to reduce air pollution and derive health benefits. The current development in air quality management is still impeded by two major obstacles: (1) biased air quality concentrations from air quality models and (2) inaccurate exposure risk estimations

Inspired by more available and overwhelming data, machine learning …


Mining Crowdsourced Data For Pavement Maintenance, Incident Management, And Traffic Monitoring, Yangsong Gu May 2023

Mining Crowdsourced Data For Pavement Maintenance, Incident Management, And Traffic Monitoring, Yangsong Gu

Doctoral Dissertations

Crowdsourcing has been a prevailing fashion of data acquisition thanks to the proliferation of smart devices and wireless communication techniques. In the transportation field, emerging crowdsourcing data could potentially facilitate traffic operation and management. A motiving example is Waze, which is a navigation app that allows Waze users (Wazers) to report different types of traffic incidents e.g., accidents, jams, potholes, disabled vehicles, and so on. Crowdsourced data has many advantages over existing fixed location sensors: cost-effective, extensive geographic coverage, high resolution, and real-time. Moreover, it assembles the human’s perception and judgment of traffic incidents, which is more straightforward compared to …


Little River Shoreline Stabilization Project, Natalie M. Hester, Steven Connor Tremyane, Libby Vanderloo, Isaac Macon May 2023

Little River Shoreline Stabilization Project, Natalie M. Hester, Steven Connor Tremyane, Libby Vanderloo, Isaac Macon

Chancellor’s Honors Program Projects

No abstract provided.


A Study On Early Age Properties Of Concrete For Precast And 3d Printing, Debalina Ghosh Dec 2022

A Study On Early Age Properties Of Concrete For Precast And 3d Printing, Debalina Ghosh

Doctoral Dissertations

Concrete is the second-most consumed material, leading the global Portland cement production of 4.1 billion tons in 2020 and 5-8% of global Carbon dioxide (CO2) emission annually. As with any other material and practice, the construction industry is also ever-changing to meet market demand, evolving technology, and resource limitation. In the case of concrete construction, one of the main concerns is the lack of automation. In the last few decades, some new construction methods have risen to address this concern. Some of these economic and successful practices are precast construction, self-compacting concrete (SCC), and 3D printing of concrete(3DPC). …


Evaluating Impacts Of Shared E-Scooters From The Lens Of Sustainable Transportation, Nitesh Shah Dec 2022

Evaluating Impacts Of Shared E-Scooters From The Lens Of Sustainable Transportation, Nitesh Shah

Doctoral Dissertations

As the popularity of shared micromobility is increasing worldwide, city governments are struggling to regulate and manage these innovative travel technologies that have several benefits, including increasing accessibility, reducing emissions, and providing affordable travel options. This dissertation evaluates the impacts of shared micromobility from the perspective of sustainable transportation to provide recommendations to decision-makers, planners, and engineers for improving these emerging travel technologies.

The dissertation focuses on four core aspects of shared micromobility as follows: 1) Safety: I evaluated police crash reports of motor vehicle involving e-scooter and bicycle crashes using the most recent PBCAT crash typology to provide a …


Fundamental Investigation Of Interaction Between Moisture And Asphalt-Aggregate Systems, Rui Xiao Dec 2022

Fundamental Investigation Of Interaction Between Moisture And Asphalt-Aggregate Systems, Rui Xiao

Doctoral Dissertations

Moisture-induced damage is one of the most common forms of flexible pavement distress which directly causes or exacerbates pavement failure. The intrusion of moisture into the asphalt pavements reduces the overall mechanical properties of the locking structures and gives rise to one or more of the visible forms of distress such as raveling, stripping, permanent deformation and fatigue cracking. This doctoral study is aimed at understanding the detrimental action of water on the asphalt-aggregate systems and the damage mechanism by multi-technique investigation. A thermodynamics framework was considered to characterize the properties of asphalt mix ingredients as well as the engineering …


Emerging Trends In Bus Ridership In The United States, Abubakr Ziedan Dec 2022

Emerging Trends In Bus Ridership In The United States, Abubakr Ziedan

Doctoral Dissertations

Public transit ridership in the United States was declining even before the COVID-19 pandemic. Many different factors affect transit ridership levels, and the recent declines in ridership across the country make it critical to assess which factors are causing declines and which may help to increase ridership. Therefore, this dissertation seeks to quantify the impact of three emerging factors on bus ridership: shared electric scooters (e-scooters), new fare payment technologies and policies, and the COVID-19 pandemic.

This dissertation analyzed the impacts of shared e-scooters on bus ridership. This was investigated at the route level in Louisville, KY, and Nashville, TN, …


A Study Of Readiness For Transportation Electrification And Automation Focusing On Safety And Future Adoption, Steve Lee Dec 2022

A Study Of Readiness For Transportation Electrification And Automation Focusing On Safety And Future Adoption, Steve Lee

Doctoral Dissertations

Transportation electrification and automation are growing societal trends and considered promising pathways to enhance the safety, mobility, efficiency, and sustainability of the surface transportation system. At this early stage of transportation electrification and automation, one of the most critical issues is whether and to what extent people are willing to adopt electric vehicle (EV) and automated vehicle (AV) technologies in the future. Another critical issue, especially concerning transportation automation, is how to thoroughly ensure the safety of automated driving performance to resolve safety concerns about AVs, which is one of the key challenges to AV adoption. In this regard, the …


Joint Failure Probability Of Dams Based On Probabilistic Flood Hazard Analysis, Matthew G. Montgomery Dec 2022

Joint Failure Probability Of Dams Based On Probabilistic Flood Hazard Analysis, Matthew G. Montgomery

Masters Theses

Probabilistic risk methods are becoming increasingly accepted as a means of carrying out risk-informed decision making regarding the design and operation of structures such as dams. Probabilistic risk calculations require the quantification of epistemic and aleatory uncertainties not investigated through deterministic methodologies. In this hydrological study, a stochastic sampling methodology is employed to investigate the joint failure probability of three dams in adjacent, similarly sized watersheds within the same Hydrologic Unit Code (HUC) 6 basin. A Probabilistic Flood Hazard Analysis (PFHA) framework is used to simulate the hydrologic loading of a wide range of extreme precipitation events across the combined …


Performance Evaluation Of Sediment Basin Designs For Highway Construction Sites In Tennessee, Jeffery Cole Emmett Jr Dec 2022

Performance Evaluation Of Sediment Basin Designs For Highway Construction Sites In Tennessee, Jeffery Cole Emmett Jr

Masters Theses

Performance of three sediment basin designs were tested; they were: 1) the TDEC standard design with a forebay, 2) the TDOT design with an inlet check dam, and 3) the TDOT standard design that does not include an inlet check dam. An 1/17 of an acre scaled physical model sediment basin, was constructed next to an elevated outdoor open flume used to mix known water volumes and sediment mass routed by gravity-flow into the basin. The measurement for performance was simply the percent sediment mass retained in the basin from the total input per experimental run (percent sediment removal). Three …


Abiotic And Biotic Degradation Of Bisphenols, Yanchen Sun Aug 2022

Abiotic And Biotic Degradation Of Bisphenols, Yanchen Sun

Doctoral Dissertations

Bisphenol A (BPA), as well as its substitutes bisphenol S (BPS) and bisphenol AF (BPAF), are high production volume chemicals and potential endocrine disruptors. The oxidized manganese (Mn) species, soluble Mn(III) and solid Mn(IV) (i.e., MnO2), are typically generated in Mn-cycling driven by Mn-oxidizing bacteria and Mn-reducing bacteria. MnO2 is a strong oxidant capable of oxidizing a variety of organic contaminants including bisphenols. Soluble Mn(III) commonly occurs near oxic-anoxic interfaces and is an important environmental oxidant. Mn(III) is also associated with both biogenic and synthesized MnO2. However, the effect of Mn(III) on the degradation of …


Investigating The Blending Mechanism And Strength Development Of 100% Hot In-Place Recycled Asphalt Mixtures, Yuetan Ma Aug 2022

Investigating The Blending Mechanism And Strength Development Of 100% Hot In-Place Recycled Asphalt Mixtures, Yuetan Ma

Doctoral Dissertations

The current tendency in the asphalt paving industry is to increase the utilization of recycled asphalt pavement (RAP). Hot in-place recycling (HIR) is a promising approach to consume 100% RAP from the existing pavement for pavement surface rehabilitation in the field. However, some concerns remained regarding the utilization of HIR techniques in pavement rehabilitation: 1. Whether it is cost-effective to apply the in-place recycling techniques to pavement rehabilitation compared to the conventional HMA surface milling & filling? 2. How to improve the performance of the asphalt mixtures with HIR technique? 3. How much RAP binder can be available for coating …


Deep Learning-Based Robotic Perception For Adaptive Facility Disinfection, Da Hu Aug 2022

Deep Learning-Based Robotic Perception For Adaptive Facility Disinfection, Da Hu

Doctoral Dissertations

Hospitals, schools, airports, and other environments built for mass gatherings can become hot spots for microbial pathogen colonization, transmission, and exposure, greatly accelerating the spread of infectious diseases across communities, cities, nations, and the world. Outbreaks of infectious diseases impose huge burdens on our society. Mitigating the spread of infectious pathogens within mass-gathering facilities requires routine cleaning and disinfection, which are primarily performed by cleaning staff under current practice. However, manual disinfection is limited in terms of both effectiveness and efficiency, as it is labor-intensive, time-consuming, and health-undermining. While existing studies have developed a variety of robotic systems for disinfecting …