Theses and Dissertations
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ArticleInvestigating the utility of personalized learning experiences for chemistry students through technological classroom integrations( 2024-08)This dissertation comprises work developing and leveraging technology as a means to aid student learning as well as to provide access to course-specific information. As technology continues to advance, tools are being developed and adopted by instructors to help fill gaps in previous systems and further extend their usefulness in the classroom. Two technologies discussed here are intelligent tutoring systems and chatbots. Intelligent tutoring systems have been deployed in a variety of fields and follow along with student work to provide hints and feedback. Chatbots, over the last several years, have grown in popularity and can be seen in a variety of fields and applications. The usefulness of curated chatbots was specifically investigated here. The first chapter provides an overview of these technologies. The next several chapters will detail work involving the Open-Response Chemistry Cognitive Assistance (ORCCA) tutor. This dynamically scaffolded intelligent tutoring system is designed to aid students with quantitative exercises in the general chemistry classroom. An overview of the system and its use in the classroom are examined, along with a more detailed look into the extension of model tracing to allow for the solving of quantitative problems in a free-form fashion. In addition to the development of the system, a look into students’ use of the system and their thoughts when comparing it to other homework systems will also be discussed. Lastly, work describing the development and incorporation of a curated syllabus chatbot will be reported on, along with a conclusion chapter that discusses the overall conclusions from the dissertation as well as an outlook on future research relating to the work presented.
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ArticleUsing socio-technical water systems in construction engineering to address water insecurity after Hurricanes Maria and Fiona( 2024-08)Water insecurity, characterized by insufficient, unreliable, and costly water necessary for a healthy life, is a significant issue in Puerto Rico, particularly affecting rural and low-income areas. The situation is worsened by historical challenges in water management, poor water infrastructure, and the impact of natural disasters like hurricanes, which intensify pre-existing water problems in vulnerable communities. Puerto Rico, an island frequently hit by hurricanes, experienced severe damage from Hurricanes Maria and Fiona in September 2017 and 2022, respectively. The island's financial crisis in recent years has hindered its capacity to invest in and maintain its water systems, leading to frequent disruptions in water supply and issues with water quality, including dangerous levels of lead and bacteria, presenting considerable health risks. Despite the extensive damage caused by hurricanes, recovery efforts have focused more on housing and roads than on water infrastructure, resulting in inadequate attention to water system restoration. The neglect of water infrastructure recovery has significant health, livelihood, and well-being implications worldwide. In Puerto Rico, water insecurity is associated with adverse health effects, including waterborne diseases like diarrhea and cholera, as well as skin conditions and diseases such as leptospirosis. Nevertheless, research is scarce on the specific complexities of water insecurity exacerbated by natural disasters and their impact on mental health and overall well-being in Puerto Rico. This dissertation presents an in-depth study focused on understanding the post-disaster environment in Puerto Rico after Hurricanes Maria and Fiona, with an emphasis on water insecurity. The proposal is structured into four main chapters, each exploring different aspects of water insecurity. Chapter 2 delves into the gap between knowledge and behavior regarding tap water consumption, posing the question, "Why do Puerto Rican consumers continue to consume tap water despite knowing or believing it to be unsafe?" The methodology involves conducting household surveys (N = 154) from May to July 2022, as well as in-depth interviews (N = 154) in the same period in the municipalities of Loíza, Comerío, and Aguas Buenas. The data collected from these surveys and interviews were analyzed using descriptive statistics and qualitative analysis. The findings identify four distinct groups of individuals based on their trust perceptions and behaviors towards drinking water. Two groups demonstrate alignment between their trust in tap water and their corresponding behavior—either they trust and drink tap water, or they mistrust it and avoid it. The other two groups exhibit a gap or misalignment, showing counterintuitive behavior; they might drink tap water despite mistrust or avoid it despite trust, influenced by socio-economic factors or long-term habits of using tap water without adverse health effects. Additionally, the findings reveal a general mistrust among consumers towards tap water, primarily attributed to its unsatisfactory quality over the past decade, as evidenced by its taste, color, and odor. Chapter 3 of the dissertation presents the development and initial psychometric evaluation of the Water Quality Perception Scale (WQPS). This chapter addresses a gap identified in the original work by Doria et al. (2009), where the items were treated as individual indicators. It aims to assess whether these items collectively represent a single, unified construct of water quality perception or if they should be considered as separate indicators. The study involved conducting an exploratory factor analysis (EFA) on 18 items with a group of 154 respondents. The EFA revealed a primary factor which encompassed 13 of the items. Additionally, two other factors emerged, represented by the remaining 5 items. To further validate the scale, a confirmatory factor analysis (CFA) was conducted with 147 participants. This group included both original participants (n=74), reassessed after six months, and new participants (n=73). The CFA results supported the initial findings, confirming the loadings of the 13-item WQPS on a single factor. The scale exhibited strong internal consistency, as evidenced by Cronbach's alpha coefficients of 0.91 and 0.89 in the two samples. Moreover, the WQPS showed convergent validity with the Household Water Insecurity Experiences Scale (HWISE), with correlation coefficients of -0.41 and -0.49 in the respective samples. Chapter 4 investigates the relationship between the combined effect of organoleptic perceptions of tap water and trust in the water utility on drinking water source preference amongst Puerto Rican consumers. The research question is; “How do organoleptic perceptions of drinking water and consumer trust in water utilities jointly affect the choice of drinking water sources in Puerto Rico?” To answer these, 154 surveys were collected from May 2022 to July 2022 in the municipalities of Loíza, Comerío, and Aguas Buenas. To investigate the associations between organoleptic perceptions of drinking water, trust in Puerto Rico Aqueduct and Sewer Authority (PRASA), and choices of drinking water sources, descriptive statistics and correlations were calculated initially. Logistic regression analyses were then utilized to assess how these variables incrementally predict the choice of drinking water sources. An alpha level of 0.05 was set to determine statistical significance. The results show that the predictive accuracy of preferences for tap versus bottled water sources improves when factors like color perception, odor perception, and trust in the water utility (PRASA) are considered alongside taste perception of tap water. This indicates that taste perception alone is not sufficient to fully understand people's drinking water preferences. Including these additional factors provides a more complete and accurate assessment of why people choose certain drinking water sources. Finally, chapter 5 of the dissertation focuses on exploring the relationship between different drinking water sources and psychological resilience among older adults in low-income areas of Puerto Rico. Psychological resilience is defined as the ability of individuals to recover from traumatic experiences, such as hurricanes. The research question posed is, "How do tap and alternative drinking water sources, like bottled water and well water, affect the psychological resilience of older adults in these Puerto Rican communities?" The study utilizes survey data collected from 209 respondents during the summer of 2021 in the municipality of Loíza. This data was analyzed using linear regression models to assess the impact of water source choices on psychological resilience. The results suggest that older adults who drink tap water show higher levels of psychological resilience compared to those who consume bottled or well water. A further gender-specific analysis revealed distinct patterns. Among men, there was only a slight difference in psychological resilience based on whether they consumed tap water or not, with a marginal decrease in psychological resilience observed among tap water consumers. In contrast, a significant difference in psychological resilience was found among women, with those drinking tap water exhibiting higher levels of psychological resilience compared to those who did not consume tap water. This dissertation makes a significant contribution to both academic literature and practical applications by offering a detailed analysis of water insecurity's role in post-disaster recovery in Puerto Rico. The research has several key implications that can guide water utility operators, policymakers, and other stakeholders in enhancing water safety and reliability. Firstly, the dissertation identifies consequences of not providing reliable access to clean piped water in homes. This finding is vital for water utility operators and policymakers, as it calls for immediate action to improve water infrastructure and access, particularly in the aftermath of disasters. Secondly, the dissertation brings to light the knowledge-behavior gap in utility management. This gap has significant implications for both utility companies and consumers. By understanding why there is a disconnect between the functioning of utilities and consumer water consumption patterns, utility companies can devise more effective strategies. These strategies could include a combination of education, incentives, and easily accessible information to empower consumers to make informed decisions and trust in the efficient use of water resources. Thirdly, the research provides insights into the empirical water quality compared to consumers' perceptions of water quality in Puerto Rico. This comparison is crucial for policymakers and local organizations, enabling them to identify and address discrepancies between actual water quality and perceived water quality. Addressing these discrepancies is essential in the ongoing recovery efforts and in improving water quality sustainably. Finally, the dissertation highlights the impact of water insecurity on the mental well-being of Puerto Rican consumers. Understanding the relationship between water insecurity and mental health aspects such as psychological resilience is pivotal. This understanding can guide water utility providers and policymakers in developing focused interventions and strategies aimed at enhancing the mental health of those affected by water insecurity. Overall, the dissertation offers a comprehensive framework for addressing water insecurity in Puerto Rico, with implications that extend beyond immediate recovery efforts to long-term policy and practice improvements in water quality management and mental health support.
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ArticleLight-driven activation: Developing photoremovable protecting groups for synthesis and biomedical applications( 2024-08)This dissertation encompasses an interdisciplinary exploration of Photo-removable protecting groups (PPGs), which includes identifying novel PPGs, performance optimization of existing PPGs and demonstration of their applications. The research delves into the design and optimization of PPGs for biomedical fields, emphasizing the importance of tailored structural features for optimal function within biological environments. Especially, 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based PPGs were refined to improve the efficiency of photorelease in the NIR (Near Infra-Red) region addressing a critical shortcoming of previously reported NIR absorbing BODIPY-based PPGs. This was achieved via structure rigidification and trapping the intermediate cation, resulting in a maximum of ~50-fold improvement in quantum yield of release (Φr) than the previous BODIPY-based similar PPGs. Complementing these efforts, structure-photoreactivity studies aimed at enhancing the deprotection efficiency of BODIPY-based PPGs provide profound insights into the correlation between substituted functional groups and Φr. Both Electron-donating groups (EDG) and electron-withdrawing groups (EWG) were used to assess the effect on Φr when substituted at the boron and 2-core positions. While EDGs improved the Φr, EWGs had the opposite effect. Additionally, the substitution at the meso methyl position by aryl groups unexpectedly lowered the Φr indicating the presence of competing photophysical/photochemical pathways. Furthermore, in this dissertation strategic design initiatives targeting a pyridinium-based zwitterionic PPG for biological applications are discussed. This zwitterionic PPG showed excellent water solubility and a great release efficiency at biological pH compared to similar-sized PPGs, showcasing its potential applications in light-triggered biomolecule activity modulation. Finally, the dissertation highlights a proof of principle study demonstrating the applicability of BODIPY-based PPGs in glycan synthesis, broadening their utility beyond the most studied biological applications. This study showed a synthesis of trisaccharide with an impressive 70% yield with just one purification. Collectively, these findings underscore the interdisciplinary nature of the research, demonstrating PPGs’ potential to be used in biology and synthetic chemistry.
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ArticleProbe and connected vehicle data for enhancing traffic management and road safety: A study of work zone crashes, dynamic message sign efficiency and smart work zone public information( 2024-08)As traffic congestion and road safety remain paramount concerns, utilizing advanced technologies and data-driven approaches has become critical in transportation engineering. The objective of this research is to examine the use of crowdsourced probe data, including segment speed data and connected vehicle data, to enhance road safety and improve traffic management. Five studies were undertaken that explored novel applications of these datasets. Segment speed data is in widespread use by agencies to monitor congestion, but its effectiveness as a predictor of crashes has not been studied much. The first study examines traffic flow characteristics in work and non-work zone environments to understand their implications on road crashes at the segment level. Segment speed data is used to develop performance indicators that are combined with related factors to develop a mixed effect linear regression model of crashes. Significant correlations were found between congestion, certain travel metrics, and crash rates, particularly in rural interstates and inactive work zones. The second study is the first to use connected vehicle data to investigate the effectiveness of dynamic message signs (DMS). Three separate analyses were undertaken. An initial analysis incorporated measurements of changes in speeds from 26 DMS locations and showed a statistically significant impact of DMS messaging on vehicle speeds. This was followed up by a broader analysis incorporating data from 48 locations and effects on speed under different types of message content. The results showed that most message categories had a statistically significant impact on speeds, generally reducing them, with varying amounts of impact. An additional analysis of DMS sign impact examined the impact of message content by considering the message sentiment. Large language models were utilized to classify the message sentiment as positive, negative, or neutral. Messages with positive sentiment and neutral undertones reduced speeds slightly, as determined by the mixed effect model. The final study explores the reliability of segment speed data and connected vehicle data sources for driving queue warnings in smart work zones. The study compares these against ground truth sensor data to evaluate the suitability of crowdsourced data for smart work zone applications. Study findings demonstrate that connected vehicle data has poor data coverage during overnight periods but is able to yield performance measures with low numbers of missed calls, exhibits low latency in detecting congestion onset, and may hold promise for providing queue warning applications if the number of false calls can be addressed by improving market penetration or improved methodology. Segment speed data had better coverage but longer latency and had many missed calls.
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ArticleA comprehensive framework for stakeholder management in utility coordination on highway projects( 2024-08)Utility coordination in highway projects requires the collaboration of multiple stakeholders, each with diverse claims, expectations, concerns, interests, and needs that do not necessarily align. As each stakeholder can influence the utility coordination process either positively or negatively at any stage of highway project development, effectively managing them and balancing their interests and needs is essential. This study aims to contribute to the utility coordination field by developing a comprehensive framework that can serve as a generic reference to guide the management of utility coordination stakeholders in highway projects. The framework's development begins with understanding the essential elements associated with successful stakeholder management, achieved through the identification and prioritization of Critical Success Factors (CSFs) for stakeholder management in utility coordination. Furthermore, to complement the framework and enhance its practical application, various methods for managing utility coordination stakeholders are compiled and classified to align with its main components. In order to achieve the objectives of this study, researchers conducted a systematic literature review of relevant studies in this field, followed by interviews with utility coordination Subject Matter Experts (SMEs), a survey questionnaire distributed to utility coordination practitioners from Departments of Transportation (DOTs) across the nation, and a focus group interview with SMEs. The results were further validated through interviews with utility coordination practitioners, who are the potential end users of this study's contributions. The findings are expected to serve as a road map to help practitioners evaluate their stakeholder management practices in utility coordination, identify areas for improvement, and prioritize efforts to increase the likelihood of successfully managing utility coordination stakeholders.