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ItemUnveiling air pollution-related health inequality in China’s food system(Georgia Institute of Technology, 2024-03) Zheng, Lianming ; Adalibieke, Wulahati ; Zhou, Feng ; He, Pan ; Chen, Yilin ; Guo, Peng ; He, Jinling ; Zhang, Yuanzheng ; Xu, Peng ; Wang, Chen ; Ye, Jianhuai ; Zhu, Lei ; Shen, Guofeng ; Fu, Tzung-May ; Yang, Xin ; Zhao, Shunliu ; Hakami, Amir ; Russell, Armistead G. ; Tao, Shu ; Meng, Jing ; Shen, HuizhongFood consumption contributes to the degradation of air quality in regions where food is produced, giving rise to an often-neglected form of environmental inequality, i.e., the contrast between the environmental health burden caused by the food consumption of a specific population and that they encounter as a consequence of food production activities. Herein, we explore this inequality within China’s food system, by linking air pollution–related health burden from the production side to the consumption side at high levels of spatial and sectorial granularity. Our findings reveal that low-income groups bear a 70% higher air pollution-related health burden from the food production than is caused by their food consumption, while high-income groups benefit from a 29% lower health burden relative to their food consumption. This discrepancy can be primarily attributed to the significant concentration of the low-income population residing in food production areas, thereby exposing them to higher emissions from agricultural activities. Our study indicates that comprehensive interventions targeting both production and consumption sides can effectively reduce health damages and concurrently mitigate associated inequalities, while singular interventions exhibit limited efficacy. This emphasizes the need for a combination of measures to establish a sustainable and equitable food system.
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ItemMetagenomic evaluation of the performance of passive Moore swabs for sewage monitoring relative to composite sampling over time resolved deployments(Georgia Institute of Technology, 2024-01) Cha, Gyuhyon ; Zhu, Kevin J. ; Fisher, Jamie M. ; Flores, Camryn I. ; Brown, Joe ; Pinto, Ameet ; Hatt, Janet K. ; Konstantinos, Kostas T. ; Graham, Katherine E.Moore swabs have re-emerged as a versatile tool in the field of wastewater-based epidemiology during the COVID-19 pandemic and offer unique advantages for monitoring pathogens in sewer systems, especially at the neighborhood-level. However, whether Moore swabs provide comparable results to more commonly used composite samples remains to be rigorously tested including the optimal duration of Moore swab deployment. This study provides new insights into these issues by comparing the results from Moore swab samples to those of paired composite samples collected from the same sewer lines continuously over six to seventy-two hours post-deployment, during low COVID-19 prevalence periods. Our results show that Moore swabs accumulated approximately 10-fold higher PMMoV concentrations (on a basis of mL of Moore swab squeezed filtrate to mL of composite sewage) and showed comparable trends in terms of bacterial species abundance when compared to composite samples. Moore swabs also generally captured higher SARS-CoV-2 N1/N2 RNA concentrations than composite samples. Moore swabs showed comparable trends in terms of abundance dynamics of the sewage microbiome to composite samples and variable signs of saturation over time that were site and/or microbial population-specific. Based on our dual ddRT-PCR and shotgun metagenomic approach, we find that Moore swabs at our sites were optimally deployed for 6 hours at a time at two sites.
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ItemResidual Deterrence In Action: Exploring The Impact Of License Plate Readers In Warner Robins' Smart City Digital Twin Model(Georgia Institute of Technology, 2023-12-13) Sonar, Nidhi SandipWith an emphasis on crime prevention, this thesis investigates the residual effect of License Plate Readers (LPRs) within a Smart City Digital Twin (SCDT) model. It highlights the integration of Artificial Intelligence (AI) and LPRs for improved surveillance while tracing the historical background of crime. The study presents the Warner Robins SCDT model, which shows encouraging outcomes in the use of dynamic LPR deployment to curb criminal acts. The residual effect of LPRs, which shows continued deterrence even after relocation, is analyzed using statistical tests on the crime records of Warner Robins (WR) and the location of cameras during the intervention period of eighteen weeks. The results demonstrate the presence of a residual effect for the period under consideration, and the possibility of yielding unique results or insights through advanced testing and research based on different parameters.
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ItemAccessibility To Healthcare Via Public Transit: A Case Study Of The Atlanta Metropolitan Area(Georgia Institute of Technology, 2023-12-12) Baral, IveeAccess to transportation is one of the major social determinants of health (SDOH). Environmental conditions where people are born, live, learn, work, play, worship, and age have an impact on a variety of health, functioning, and quality-of-life outcomes and risks; these conditions are known as social determinants of health (American Hospital Association, 2023). For households without cars, public transportation is essential for accessing healthcare (Liu et al., 2022). Adequate public transportation can help ensure patients are able to attend their healthcare appointments as scheduled and decrease the number of missed appointments. On the other hand, a lack of public transit could disrupt health outcomes by leading to delayed diagnoses or exacerbating existing conditions (American Hospital Association, 2023). Due to varying socioeconomic factors such as race, ethnicity, and car ridership, different households have unequal access to healthcare, so transit is their only way of reaching healthcare facilities (Liu et al., 2022). This study will investigate the accessibility of healthcare in the Atlanta Metropolitan Area via MARTA bus routes to understand how accessible healthcare is for transit-dependent individuals. Transit dependency constitutes individuals who have limited access to other modes of transportation, such as those above 65, below 18, and people with disabilities (American Public Transit Association, 2017). The goal of this study is to identify the census tracts in the study area that have limited access to healthcare facilities via transit, especially for transit-dependent people. The study will focus on the MARTA bus routes rather than the MARTA rail, as there is greater reach through the bus network.
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ItemAn observational and modeling study of energy, water, and carbon transport in eco-hydro-meteorological systems(Georgia Institute of Technology, 2023-12-12) Zhu, ModiEco-hydro-meteorological systems play a critical role in regulating the Earth's energy, water, and carbon cycles. Understanding the physical mechanisms driving ecosystem functioning is essential for predicting and mitigating the impacts of global environmental change. The primary objective of this study is to understand the complex mechanisms and interactions that govern the transport of energy, carbon, and water in various eco-hydro-meteorological systems. However, the mechanisms in different eco-hydro-meteorological systems are quite different. This study, by employing a blend of observational data and modeling techniques, investigates the physical transportation of energy, water, and carbon within diverse ecosystems --forest, permafrost, and lake --each with its distinct mechanisms, and develops a comprehensive understanding of how these ecosystems function and respond to environmental changes. In the observational phase, data is gathered using flux towers that measure the exchange of energy, water, and carbon between the Earth's surface and the atmosphere. Datasets from multiple flux towers across forest, permafrost, and lake ecosystems are scrutinized to discern patterns and drivers of eco-hydro-meteorological system processes. The observations have revealed the differences of how energy, water, and carbon are transported in different eco-hydro-meteorological systems and the importance of further study. In the modeling phase, the past traditional models of energy, water, and carbon transport of eco-hydro-meteorological systems have been carefully reviewed. The non-gradient models are widely applied in modeling the meteorological processes in recent decades. This study utilizes Maximum Entropy Production (MEP) Model and Half-order Derivative (HOD) Methods together with newly proposed inference models to simulate the eco-hydro-meteorological processes, which yielded consistent results compared to field experiments. Overall, this study has significant implications for our understanding of how eco-hydro-meteorological systems function and how they respond to environmental changes. The knowledge gained from this research could inform the development of policies and strategies to promote environmental sustainability and protect these vital ecosystems for future generations.
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ItemAn observational and modeling study of energy, water, and carbon transport in eco-hydro-meteorological systems(Georgia Institute of Technology, 2023-12-11) Zhu, ModiEco-hydro-meteorological systems play a critical role in regulating the Earth's energy, water, and carbon cycles. Understanding the physical mechanisms driving ecosystem functioning is essential for predicting and mitigating the impacts of global environmental change. The primary objective of this study is to understand the complex mechanisms and interactions that govern the transport of energy, carbon, and water in various eco-hydro-meteorological systems. However, the mechanisms in different eco-hydro-meteorological systems are quite different. This study, by employing a blend of observational data and modeling techniques, investigates the physical transportation of energy, water, and carbon within diverse ecosystems --forest, permafrost, and lake --each with its distinct mechanisms, and develops a comprehensive understanding of how these ecosystems function and respond to environmental changes. In the observational phase, data is gathered using flux towers that measure the exchange of energy, water, and carbon between the Earth's surface and the atmosphere. Datasets from multiple flux towers across forest, permafrost, and lake ecosystems are scrutinized to discern patterns and drivers of eco-hydro-meteorological system processes. The observations have revealed the differences of how energy, water, and carbon are transported in different eco-hydro-meteorological systems and the importance of further study. In the modeling phase, the past traditional models of energy, water, and carbon transport of eco-hydro-meteorological systems have been carefully reviewed. The non-gradient models are widely applied in modeling the meteorological processes in recent decades. This study utilizes Maximum Entropy Production (MEP) Model and Half-order Derivative (HOD) Methods together with newly proposed inference models to simulate the eco-hydro-meteorological processes, which yielded consistent results compared to field experiments. Overall, this study has significant implications for our understanding of how eco-hydro-meteorological systems function and how they respond to environmental changes. The knowledge gained from this research could inform the development of policies and strategies to promote environmental sustainability and protect these vital ecosystems for future generations.
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ItemAnalysis Of Infrastructure Investments And Jobs Act, Federal Compliances, Issues And Determining A Framework Of Resources For Compliance Management(Georgia Institute of Technology, 2023-12-05) Aggarwal, AyushThe Infrastructure Investments and Jobs Act (IIJA) is a historic legislation bipartisan bill that has empowered the infrastructure development agencies with grants to undertake capital projects to meet the infrastructural needs of the USA. The study presents an analysis of the funding with around a fifth of the funding dedicated to the roads, bridges, and other major projects segment. The study sheds light on the tenets and objective of the government spending and also presents programs and grants available. It further elaborates on how these grants are classified as formula and discretionary and explains the fundamental differences in these granting methods. The study analyzes public data to determine the breakdown of the funding for the available formula grants. Chapter 3 of the study elaborates on the grant lifecycle to elaborate and educate the reader on the grant lifecycle from pre-award to post-award compliance requirements. The literature review and professional seminars indicated the lack of development of internal controls regarding federal compliance requirements by local public agencies and non-conventional grant recipients have hampered the agencies from accessing such funding opportunities. Therefore, this study highlights the major compliance areas required for federal participation in highway transportation construction projects. The study highlights the matrices published by the government for funding opportunities, and subsequently highlights the challenges with the compliance requirements. 5 challenges were recognized and subsequently 14 general compliance areas were identified for non-conventional entities to develop their internal controls and procedures. 11 federal compliance areas were identified where such compliance requirements might arise in the federally aided projects. These 11 areas are elaborated for the compliance requirements and subsequently chapter 8 provides tools and existing resources for development of such compliance requirements for the departments. Chapter 9 of the study recognizes 11 existing frameworks of resources that can be leveraged by the agencies for management of the federal compliance requirements. The summary of the existing frameworks like the USDOT Technical assistance programs and Local Technical Assistance programs will guide the readers toward the correct and relevant information regarding the compliance areas. Finally, this research while elaborating and highlighting federal compliance requirement management for the local public agencies highlights the need for a dynamic compliance navigator tool that integrates the available public resources by various organizations to streamline the federal compliances and enhance safety, quality and integrity of the project. The streamlined compliance navigator will aid the government in this massive undertaking of infrastructural development and deliver the projects On Time and on Budget.
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ItemEvaluation of Large-Format Metallic Additive Manufacturing (AM) for Steel Bridge Applications: Final Report of Tensile, Impact, and Fatigue Testing Results(Georgia Institute of Technology, 2023-10-11) Sherman, Ryan J. ; Kessler, Hannah D. ; Frank, Karl H. ; Medlock, RonnieWire arc additive manufacturing (WAAM) is an additive manufacturing process capable of printing using metallic feedstocks, such as traditional welding wire consumables. Advances in WAAM allow large-scale components, measured on the scale of feet, to be fabricated. A lack of fundamental knowledge of the material and fatigue behaviors of WAAM currently prevents its widespread adoption into structural engineering. To address this need, the first objective of this work was to create material property datasets for WAAM ER70S-6 and ER80S-Ni1through tension and notched bar impact (Charpy V-notch) tests. The second objective was to determine the influence of the as-fabricated surface finish on the fatigue behavior of WAAM ER70S-6 steel components through uniaxial fatigue tests on specimens. No significant anisotropy (difference in properties with respect to the build direction and deposition direction of the part) was noted in the yield and tensile strengths of the WAAM ER70S-6and ER80S-Ni1 material. Low levels of anisotropy were observed in the elongation at fracture of the tensile specimens and the impact energies of the CVN specimens. The impact energies of all WAAM specimens tested at or above the AASHTO service temperatures exceeded the fracture critical Grade 50 steel requirement. Fatigue specimens with the machined surface finish exceeded the upper bound life of AASHTO fatigue detail category A.A 95 percent confidence limit regression with the slope set to 3.0 for all the as-built surface specimens exceeded AASHTO fatigue detail category D.
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ItemDemographic Breakdown of Transit Rider Satisfaction(Georgia Institute of Technology, 2023-10) Mers, Bianca ; Watkins, Kari E. ; Hunter, Michael P.With ridership declining nationally and transit agencies looking for innovative ways to maintain and attract riders, a more complex understanding of transit riders and their satisfaction could provide additional insight and guidance to benefit the future of transit. This study challenged the traditional captive versus choice rider dichotomy and indicates the need for a more nuanced breakdown of transit riders based on the attributes most important to them. To conduct the analysis, the authors obtained rider survey data from nine agencies across the United States from varying geographic regions and representing various agency sizes. Agencies were selected based on their intentional use of demographic classifications and questions about satisfaction with various aspects of transit service. The authors then applied ordered logit regression across the 18,544 rider survey responses to predict the relative importance of service attributes on overall satisfaction. The findings suggested that different classifications of riders by gender, race, and income yielded diverse priorities, although certain service aspects such as reliability were important across demographics. In addition to the findings from the regression analysis, this study also offers a series of recommendations to facilitate future investigations by using more consistent, standardized data to further the breadth and depth of national transit rider analyses.
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ItemStructural Testing Of Non-Proprietary UHPC For Closure Pours Used In Standard GDOT Precast Bridge Deck Panels(Georgia Institute of Technology, 2023-08-28) Ngeme, Lixrine EpieUltra-high-performance concrete (UHPC) is a type of concrete that is known for its exceptional strength, durability, and resistance to cracking. Proprietary UHPC is primarily made by combining cement, silica fume, quartz flour, fine sand, high-range water reducers, and steel or polymer fibers. UHPC has been used in a variety of applications, including bridges, tunnels, high rise buildings, and other structures that require high strength and durability. One of the main advantages of UHPC is its ability to support high loads with relatively thin sections, which can lead to significant cost savings in construction. In 2018, researchers at the Georgia Institute of Technology developed a non-proprietary ultra-high-performance concrete (UHPC) mix that could be produced using locally available materials. The mix consisted of Portland cement, metakaolin, fine sand, water, and a high-range water reducer. The mix design demonstrates the required 28-day compressive strength of at least 18,000 psi. This UHPC mix was designed to meet the high-performance requirements of bridge construction while also being cost-effective and environmentally sustainable. The closure joint is a critical component of a bridge that accommodates the expansion and contraction of the bridge deck due to temperature changes. The UHPC mix was used to fill the closure joint between two adjacent bridge slabs. The performance of the UHPC mix in the closure joint was evaluated through a series of tests, including compression tests, and flexural tests. The UHPC mix was found to have high compressive and flexural strength, as well as excellent adhesion to the bridge decks. The primary goal for this research was to use the non-proprietary UHPC mix developed in the previous research at Georgia Institute of technology, to perform a large structural test on closure joint of bridge slabs in Georgia. Two tests were performed successfully and detailed reports from observing these tests followed. Insights were gained from these tests as to the viability of the non-proprietary mix for closure pour applications. The mix proved successful in this regard, indicated by both-large scale structural test specimens failing via crushing of the precast concrete panels rather than failure being governed by the UHPC joint. The results of the tests demonstrated that the non-proprietary UHPC mix developed in Georgia was a viable option for use in bridge construction. The UHPC mix showed superior performance compared to traditional concrete mixes and could provide a cost-effective and environmentally sustainable solution for bridge construction.