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1. Understanding crack tip pH evolution during corrosion fatigue in 2xxx and 7xxx aluminum alloys as a function of fatigue loading frequency

   Montiel, Gabriella C (May 2026, OhioLINK)

   PhD Dissertation of Gabriella Montiel from The Ohio State University who was advised by Prof Jenifer Locke 

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2. Traffic Stop: Interactive Story AI for Virtual Reality Training

   https://doi.org/10.5281/zenodo.14713659  

   Ware, Stephen G; Fisher, Mira; Siler, Molly (September 2024, Zenodo)

   Traffic Stop is a virtual reality de-escalation training simulation for police officers that has an interactive story driven by artificial intelligence. This project was funded by the U.S. National Science Foundation and led by Prof. Stephen Ware of the Narrative Intelligence Lab at the University of Kentucky. 

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3. Urban aerosol chemistry at a land-water transition site during summer – Part 2: Aerosol pH and liquid water content

   Battaglia Jr., M. A. (January 2021, Atmospheric chemistry and physics discussion)

   null (Ed.)

   Particle acidity (aerosol pH) is an important driver of atmospheric chemical processes and the resulting effects on human and environmental health. Understanding the factors that control aerosol pH is critical when enacting control strategies targeting specific outcomes. This study characterizes aerosol pH at a land-water transition site near Baltimore, MD during summer 2018 as part of the second Ozone Water-Land Environmental Transition Study (OWLETS-2) field campaign. Inorganic fine mode aerosol composition, gas-phase NH3 measurements, and all relevant meteorological parameters were used to characterize the effects of temperature, aerosol liquid water (ALW), and composition on predictions of aerosol pH. Temperature, the factor linked to the control of NH3 partitioning, was found to have the most significant effect on aerosol pH during OWLETS-2. Overall, pH varied with temperature at a rate of −0.047 K−1 across all observations, though the sensitivity was −0.085 K−1 for temperatures > 293 K. ALW had a minor effect on pH, except at the lowest ALW levels (< 1 µg m−3) which caused a significant increase in aerosol acidity (decrease in pH). Aerosol pH was generally insensitive to composition (SO42− , SO42−:NH4+ , Tot-NH3 = NH3 + NH4+), consistent with recent studies in other locations. In a companion paper, the sources of episodic NH3 events (95th percentile concentrations, NH3 > 7.96 µg m−3) during the study are analyzed; aerosol pH was higher by only ~0.1–0.2 pH units during these events compared to the study mean. A case study was analyzed to characterize the response of aerosol pH to nonvolatile cations (NVCs) during a period strongly influenced by primary Chesapeake Bay emissions. Depending on the method used, aerosol pH was estimated to be either weakly (~0.1 pH unit change based on NH3 partitioning calculation) or strongly (~1.4 pH unit change based on ISORROPIA thermodynamic model predictions) affected by NVCs. The case study suggests a strong pH gradient with size during the event and underscores the need to evaluate assumptions of aerosol mixing state applied to pH calculations. Unique features of this study, including the urban land-water transition site and the strong influence of NH3 emissions from both agricultural and industrial sources, add to the understanding of aerosol pH and its controlling factors in diverse environments. 

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4. Urban aerosol chemistry at a land–water transition site during summer – Part 2: Aerosol pH and liquid water content

   https://doi.org/10.5194/acp-21-18271-2021  

   Battaglia Jr., Michael A.; Balasus, Nicholas; Ball, Katherine; Caicedo, Vanessa; Delgado, Ruben; Carlton, Annmarie G.; Hennigan, Christopher J. (January 2021, Atmospheric Chemistry and Physics)

   Abstract. Particle acidity (aerosol pH) is an important driver of atmospheric chemical processes and the resulting effects on human and environmentalhealth. Understanding the factors that control aerosol pH is critical when enacting control strategies targeting specific outcomes. This studycharacterizes aerosol pH at a land–water transition site near Baltimore, MD, during summer 2018 as part of the second Ozone Water-Land EnvironmentalTransition Study (OWLETS-2) field campaign. Inorganic fine-mode aerosol composition, gas-phase NH3 measurements, and all relevantmeteorological parameters were used to characterize the effects of temperature, aerosol liquid water (ALW), and composition on predictions ofaerosol pH. Temperature, the factor linked to the control of NH3 partitioning, was found to have the most significant effect on aerosol pHduring OWLETS-2. Overall, pH varied with temperature at a rate of −0.047 K−1 across all observations, though the sensitivity was−0.085 K−1 for temperatures > 293 K. ALW had a minor effect on pH, except at the lowest ALW levels(< 1 µg m−3), which caused a significant increase in aerosol acidity (decrease in pH). Aerosol pH was generally insensitive tocomposition (SO42-, SO42-:NH4+, total NH3 (Tot-NH3) = NH3 + NH4+), consistentwith recent studies in other locations. In a companion paper, the sources of episodic NH3 events (95th percentile concentrations,NH3 > 7.96 µg m−3) during the study are analyzed; aerosol pH was higher by only ∼ 0.1–0.2 pH unitsduring these events compared to the study mean. A case study was analyzed to characterize the response of aerosol pH to nonvolatile cations (NVCs)during a period strongly influenced by primary Chesapeake Bay emissions. Depending on the method used, aerosol pH was estimated to be either weakly(∼ 0.1 pH unit change based on NH3 partitioning calculation) or strongly (∼ 1.4 pH unit change based onISORROPIA thermodynamic model predictions) affected by NVCs. The case study suggests a strong pH gradient with size during the event and underscores the need to evaluate assumptions of aerosol mixing state applied to pH calculations. Unique features of this study, including the urban land–water transition site and the strong influence of NH3 emissions from both agricultural and industrial sources, add to the understanding of aerosol pH and its controlling factors in diverseenvironments. 

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5. The significant impact of aerosol vertical structure on lower atmosphere stability and its critical role in aerosol–planetary boundary layer (PBL) interactions

   https://doi.org/10.5194/acp-20-3713-2020  

   Su, Tianning; Li, Zhanqing; Li, Chengcai; Li, Jing; Han, Wenchao; Shen, Chuanyang; Tan, Wangshu; Wei, Jing; Guo, Jianping (January 2020, Atmospheric Chemistry and Physics)

   null (Ed.)

   Abstract. The aerosol–planetary boundary layer (PBL) interaction wasproposed as an important mechanism to stabilize the atmosphere andexacerbate surface air pollution. Despite the tremendous progress made inunderstanding this process, its magnitude and significance still have largeuncertainties and vary largely with aerosol distribution and meteorologicalconditions. In this study, we focus on the role of aerosol verticaldistribution in thermodynamic stability and PBL development by jointly usingmicropulse lidar, sun photometer, and radiosonde measurements taken inBeijing. Despite the complexity of aerosol vertical distributions,cloud-free aerosol structures can be largely classified into three types:well-mixed, decreasing with height, and inverse structures. The aerosol–PBLrelationship and diurnal cycles of the PBL height and PM2.5 associated with these different aerosol vertical structures showdistinct characteristics. The vertical distribution of aerosol radiativeforcing differs drastically among the three types, with strong heating in thelower, middle, and upper PBL, respectively. Such a discrepancy in the heatingrate affects the atmospheric buoyancy and stability differently in the threedistinct aerosol structures. Absorbing aerosols have a weaker effect ofstabilizing the lower atmosphere under the decreasing structure than underthe inverse structure. As a result, the aerosol–PBL interaction can bestrengthened by the inverse aerosol structure and can be potentiallyneutralized by the decreasing structure. Moreover, aerosols can both enhanceand suppress PBL stability, leading to both positive and negativefeedback loops. This study attempts to improve our understanding of theaerosol–PBL interaction, showing the importance of the observationalconstraint of aerosol vertical distribution for simulating this interactionand consequent feedbacks. 

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