Examining infrared thermography based approaches to rapid fatigue characterization of additively manufactured compression molded short fiber thermoplastic composites

A novel additive manufacturing (AM) methodology combined with a compression molding (CM) process has been previously developed to optimize the microstructure of short fiber thermoplastic (SFTs) composites with higher fiber alignment and lower porosity, yielding superior stiffness, strength, and structural integrity. The current work examines the efficacy of the ‘passive’ infrared thermography (IRT) techniques for rapid fatigue characterization of SFTs that use the surface temperature evolution during cyclic loading due to self-heating as a fatigue indicator. A comparison of fatigue limits obtained from traditional stress-life (SN) (≈53.1%σuts) and IRT (≈54.1%σuts) shows a close match. However, the SN curve required 18 specimens and two weeks of continuous cyclic testing, while IRT used three specimens with 5 h of testing. Thus, the IRT approach provides an accelerated testing framework for rapidly estimating the fatigue limit. Additionally, existing phenomenological approaches to IRT fatigue characterization have been examined

ASSESSING WATER QUANTITY AND QUALITY IN THE MISSISSIPPI RIVER VALLEY ALLUVIAL AQUIFER AND COASTAL LOUISIANA THROUGH INTEGRATED AIRBORNE ELECTROMAGNETIC AND BOREHOLE DATA

Numerical modeling has contributed significantly to the understanding of groundwater systems. Many challenges are associated with constructing groundwater models which include an accurate understanding of the geology and aquifer parameters estimation. Traditionally boreholes are a successful way to capture geological features, however, boreholes often have sparse data. Airborne electromagnetic (AEM) data allows for efficient and cost-effective surveying of large areas, providing valuable information about the subsurface electrical resistivity. By bridging the gap between boreholes, AEM data offers a broader view of the aquifer system\u27s structure and heterogeneity. However, interpreting geophysical AEM data has uncertainties. Developing a framework to apply the data fusion concept on boreholes and AEM data is one of the challenges addressed in the first part of this study. The framework introduces depth-dependent resistivity thresholds and unsupervised clustering to classify resistivity into lithofacies, reducing interpretation uncertainties. Applied to the Mississippi River Valley alluvial aquifer (MRVA), the second most-pumped US aquifer, it improves lithofacies models and reduces estimation uncertainties. Employment of AEM resistivity data in groundwater quality, the second part introduces a transformation from resistivity to subsurface quality using a deep learning model and regression formulas that predict chloride concentration using location, AEM resistivity, borehole data, and water quality data. This method gives us a clear picture of the saltwater plumes in 3D for the first time. By mapping the extent and intensity of salinity in the MRVA aquifer, the model provides valuable insights into the sources and controls of groundwater salinity, supporting proactive water resources management. As the final goal of this study, a detailed groundwater model was constructed based on the complex geological model from the data fusion study. This study generates maps to guide risk-based water management decisions and protect aquifer resources by delineating the cones of depression. Moreover, it highlights the significant influence of increased groundwater pumping on groundwater levels and fresh groundwater, evaluating changes in up-coning from deeper saline aquifers through a coupled flow-transport model which enhances our understanding of groundwater flow and storage responses to excessive withdrawals. Ultimately, these findings offer critical insights for effective groundwater management in regions experiencing substantial pumping pressures

A Molecular Dynamics Modeling Framework for Shape Memory Vitrimers

Vitrimers with self-healing, recycling, and remolding capabilities are changing the paradigm for thermoset polymer design. In the past several years, vitrimers that exhibit shape memory effects and are curable by ultraviolet (UV) light have made significant progress in the realm of 4D printing. Herein, we report a molecular dynamics (MD) modeling framework to model UV curable shape memory vitrimers. We used our framework and compared our modeling results with one UV curable shape memory vitrimer found in the literature, bisphenol A glycerolate dimethacrylate. The comparison showed reasonable agreement between the modeling and experimental results in terms of thermomechanical and shape memory properties, along with self-healing efficiency. It was found that during recycling, it was important for the network to percolate through a majority of the system to get reasonably high recovery stress and recycling efficiency. Once this was achieved, a topological descriptor that was found to represent the compactness of the network was identified as having a very high correlation with recovery stress and recycling efficiency for networks that percolated 70% or more of the monomers in a system

Assessing Groundwater Availability and Land Subsidence Risk Associated with Anthropogenic Activities in a Complex Aquifer System

The Southern Hills aquifer system (SHAS) is the primary source of water in the Capital area of Louisiana. However, the overexploitation of freshwater-bearing aquifers and the presence of two active faults, the BR fault and the DSS fault, have resulted in groundwater depletion, saltwater intrusion, and increased the risk of land surface subsidence. Such critical issues pose substantial threats to groundwater availability and exert detrimental effects on the environment and urban infrastructures. This dissertation presents a comprehensive investigation of the SHAS for recognizing the consequences of groundwater depletion and its potential long-term impacts on groundwater availability and land stability. A mesh generation methodology based on 2.5D centroidal Voronoi tessellations and curve fitting is proposed to construct an unstructured grid that offers great flexibility in specifying grid connections in 3D, captures intricate geometries, and adds high levels of refinement in areas of interest. The proposed methodology is applied to develop a high-resolution groundwater model for the SHAS, serving as a pivotal tool for providing advanced insights into groundwater availability, aquifer sustainability, and spatial depletion across individual aquifers, with implications for current conditions and future projections under different withdrawal scenarios. A groundwater-subsidence model is developed to assess spatiotemporal variations in groundwater flow and subsurface compaction in the SHAS, as well as the associated vertical displacement induced by long-term groundwater pumping. This provides a substantial framework for understanding the key factors contributing to land subsidence. A transport model is developed to investigate salt migration pathways within the “2,000-foot” sand. This study not only significantly advances the understanding of groundwater availability in the SHAS but also forms the basis for robust groundwater management approaches, thereby preserving the sustainability and resilience of vulnerable areas and informing targeted mitigation strategies

A big data approach to modelling urban population density functions: from monocentricity to polycentricity

Urban studies have a long tradition of examining the regularity of urban structure by modelling urban population density functions and probing the theoretical or behavioural foundation behind it. Previous studies commonly used census data in areal units such as census tracts or census block groups, which varied a great deal in area size and shape and led to the zonal and scale effects, commonly referred to as the modifiable areal unit problem (MAUP). This study uses big data of individual vehicle trips in Tampa, Florida, to define the precise population and employment distribution locations, and then aggregates them with uniform areal units such as squares, triangles, and hexagons to examine and mitigate the scale and zonal effects. Both monocentric and polycentric models are employed in the analysis of urban population density functions. The results suggest that the exponential density function remains the best fitting monocentric function in most areal units including census units and designed uniform units. The polycentric model reveals two centres (downtown and University of South Florida) exerting influences on the areawide population density pattern. The zonal effect is not significant in the designed uniform units, but the scale effect remains evident in all areal units

En Clave Tania León and Roberto Sierra: autochthonous music of Cuba and Puerto Rico, contemporary music composition and the \u27Puente\u27 in between

This document is in two parts. The first examines selected works of Latin-American composers Tania León and Roberto Sierra. Both composers cite their cultural background as a force that shapes their artistic expression. Many of their works are titled in Spanish, with compositions referencing their homelands in subject and narrative, and incorporate the autochthonous music(s) of Cuba and Puerto Rico. Elements of these afrodiasporic musical traditions can be found in their works: Alegre, Batá, Stride, (Leon), Loiza, and Concerto for Viola (Sierra), each examined here. Autochthonous musical elements are highlighted in score excerpts and described using the language and nomenclature typical of their genres. Through examining each composer\u27s work, I hope to illustrate how those cultural elements are developed beyond their idiomatic settings and incorporated in the construction of a large-scale contemporary music composition reflecting their personal expression and unique stylistic paths. The second part presents some research into bomba, an autochthonous music of Puerto Rico. Interviews, articles and recordings are cited as sources for information about this genre’s history, development and modern practice. Bomba was first observed as a practice in Black communities in Puerto Rico in 1797 and has parallel music traditions in other colonized areas throughout the Caribbean and New Orleans.1 Bomba maintained relevance as a folk and popular music in Puerto Rico throughout the early twentieth century until it was replaced in popular music by salsa and the “Cubanization” of other Latin American music styles.2 Materials studied in this research process are incorporated into the writing of a new musical work, Bámbulas. This original composition incorporates both musical and soundscape elements of Puerto Rican bomba reinterpreted by a non-standard ensemble. The intent of this composition is to make use of some of bomba’s idiomatic elements and develop those materials over the course of a long-form composition, evoking bomba’s cultural setting and creating an expression of the life that encircles the music. 1Reinaldo L. Roman, “Scandalous Race: Garveyism, the Bomba, and the Discourse of Blackness in 1920s Puerto Rico.” Caribbean Studies 31, no. 1 (2003): 246,247. http://www.jstor.org/stable/25613394. 2Peter Manuel, “Puerto Rican Music and Cultural Identity: Creative Appropriation of Cuban Sources from Danza to Salsa.” Ethnomusicology 38, no. 2 (1994): 259. https://doi.org/10.2307/851740

Hate crime law associations with mental health and discrimination experiences among transgender and gender diverse adults

State-level hate crime laws are a proposed solution for pernicious effects endured by transgender and gender diverse (e.g., no-binary, queer) (TGD) communities. The present study investigated the following correlates of psychological distress, suicidal behavior, and discrimination experiences among TGD adults: State-level hate crime law statutes (e.g., gender identity protection), state-level attitudes (e.g., conservative ideology), and individual-level marginalized identities (e.g., sexual minority status). Participants were all TGD adults in the 2015 United States Transgender Survey (USTS). We merged three data sources: the USTS, Cooperative Congressional Election Study, and the Anti-Defamation League\u27s Hate Crime Map. We employed bivariate and logistic regression analyses. Prominent findings spanning the whole sample included: (a) worse psychological distress was associated with living in a state with greater anti-TGD attitudes and an absence of gender identity protections; (b) worse 12-month suicidal behavior was associated with living in a state with an absence of gender identity and police data collection statutes; and (c) holding multiple marginalized identities, particularly having a disability, was the strongest risk factor for experiencing negative outcomes. Findings are contextualized by debates about hate crime laws. We offer recommendations for mental health promotion and suicide prevention, hate crimes training, and future research

Campaigning in the Field: Voter Contact Strategies and the Use of Office Space in Electoral Politics

The means by which American political campaigns reach voters is constantly evolving, shaped by advancements in technology, resource constraints, and the increasing use of microtargeting to engage likely voters who are predisposed to support a particular candidate (Endres and Kelly 2018; Limbocker and You 2020). While much research focuses on campaign strategies and its effect on electoral outcomes (Kolodny and Logan 1998; Shaw 1999; Spenkuch and Toniatti 2018; Vavreck 2007), less attention is paid to studying the specific tactics of campaign strategy. Particularly in this digital age, with advanced methods of microtargeting voters and the societal shift to digital tools in the aftermath of COVID-19, the degree to which political campaigns still value and operationalize interpersonal contact through organizing and investing in physical infrastructure is becoming less clear. This dissertation, which takes the form of three separate, but related articles on the changing methods of how campaigns are reaching voters, and the utilization of field offices in electoral politics is a necessary addition to a scant but growing body of literature. In Chapter 2, using the Cooperative Election Study (CES) data, I demonstrate how voter contact changed from 2020 to 2022, with increased virtual contact during 2020 while in-person contact resurged in 2022. I show how partisanship influenced the manner of contact, with Republicans predominantly targeted through in-person efforts in 2020 and Democrats virtually, while in 2022, Democrats were more likely to be contacted in-person and virtually. I include 2012 and 2014 CES data to contextualize these findings. In Chapter 3, using an original dataset, I empirically assess the impact of the RNC’s initiative to use office space to engage minority voters and increase voter registration rates. I find that while some locations with centers appear to have demonstrated measurable gains in Republican registration, others had little to no effect. In Chapter 4, using an original dataset of Donald Trump and Kamala Harris’ field office locations, and building off prior research (Darr and Levendusky, 2014), I document a notable decline in field office investment compared to previous elections and show how the placement considerations in 2024 differed from cycles prior

Social factors associated with everyday functioning in older Black adults

Objective: Independence in everyday functioning has been associated with successful aging and declines in functioning may be indicative of pathological cognitive decline. Social determinants of health, like economic status and access to health care, a]lso play a role in everyday functioning. Understanding these factors are of particular importance for older Black adults who have had long-standing disparate access to care, education, and treatments. The current study aimed to evaluate social determinants of health, more specifically social engagement, as moderators of the association between cognition and everyday functioning. Method: A sample of 930 older Black adults from Rush University: The Memory and Aging Project, African American Clinical Core, and Minority Adult Research Study were used. Participants completed a battery of neuropsychological testing as well as questionnaires about their everyday functioning and social behaviors. Hierarchical linear regressions were utilized to determine to what extent social factors moderated the relationship between cognition and everyday functioning. Results: Late life social activity reduced the effect of global cognition on everyday functioning and was independently associated with everyday functioning. Social network size was associated with increased impairment. Conclusion: Results from the current study provide novel information regarding the role of social interaction on cognition in an older Black adult sample. Future interventions may benefit from an emphasis on increasing social engagement