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Residential buildings contribute about 22% of the national energy use in the U.S. Space heating, domestic hot water (DHW), and space cooling are the three major end uses, respectively accounting for 43%, 19%, and 8% of the residential sector’s total primary energy consumption. Currently, fossil fuels are the predominant source of energy in the residential sector. To address the problems caused by the combustion of fossil fuels, alternative renewable, low-emission, and energy-efficient technologies for heating and cooling applications in residential buildings are highly needed. In this respect, solar-assisted heat pump (SAHP) systems are a promising solution by coupling solar collectors with heat pumps that can complement each other to achieve high solar utilization and high efficiency of the heat pump.
This research proposes and evaluates a hybrid multifunctional SAHP system that can provide space heating, space cooling, DHW, and onsite electricity generation. The indirect expansion SAHP system supports both parallel and series configurations. Major components of the SAHP system include unglazed PVT collectors, a liquid-to-liquid heat pump, a thermal storage tank, a DHW tank, auxiliary electric water heaters, and pumps. Photovoltaic-thermal (PVT) collectors are used to serve three functions, including electricity generation (daytime), heat collection (usually daytime), and radiative cooling (usually nighttime). The system design and controls support fourteen operational modes involving different components for space heating, space cooling, and DHW heating.
TRNSYS software is used to model and simulate the multifunctional SAHP system. The system performance is evaluated in two locations (i.e., Baltimore, MD and Las Vegas, NV) with different climates. Based on the performance analysis of the system simulation, three potential performance improvement strategies, including replacing the thermal storage tank with an outdoor swimming pool or a tank having phase change materials for latent thermal storage, and replacing the liquid-to-liquid heat pump with a dual-source heat pump are explored. The TRNSYS simulation results are also used to calculate the simple payback period of the incremental investment associated with the multifunctional SAHP system relative to a reference air-source heat pump system.
With a 2 m3 storage tank and 30 m2 PVT collectors, the multifunctional SAHP system has a seasonal performance factor of 2.7 in Baltimore and 3.7 in Las Vegas. In comparison with the reference system, the SAHP system saves energy by 48% in Baltimore and 61% in Las Vegas. The seasonal performance factor of the SAHP system can be further improved by using a swimming pool to replace the storage tank in Las Vegas and using a dual-source heat pump in Baltimore.
Foreign aid is one of the most powerful tools at a singe state’s disposal. Economically, it can provide much needed support to the poorest of countries or those facing catastrophic conditions. Politically, it can strengthen the current government’s position and provide them with what they deem necessary to keeping their rule of law, whether they be democracies or autocracies. In addition to these effects, a donor state must also balance their own interests, which can sometimes conflict with a recipient. An alternative route that can potentially help a donor avoid such dilemmas is to divert funds through a multilateral organization instead, which can help donors avoid the need to go through another state government. Regardless of the method of disbursement though, the use of financial foreign aid has a tendency to produce effects that go far beyond its initial goal. This tendency is what this study seeks to examine. Within this context, this study seeks to empirically investigate the unintended impact that foreign aid may have on one of the world’s biggest human rights abuse: human trafficking. Human trafficking is a generations-old problem still in search of a solution. In two parts, I use an ordinal logistic regression to examine historical data in a post-Cold War era to determine the extent of foreign aid’s unintended impact on a crime yet undefined. In the first part, total financial foreign aid is examined for general impact. In the second part, financial foreign aid is split into its most common forms, bilateral aid and multilateral aid, to examine specific individualized impacts. Overall, my study reveals that there is indeed an impact on human trafficking, even though it had yet to be clearly defined at the time . In addition to that, bilateral aid experienced more statistical significance as compared to multilateral aid, suggesting that bilateral aid may have had a bigger part to play in the realm of human trafficking. The magnitude and type of relationship that foreign aid has with human trafficking appears to change over time. However, this study does have its limitations, which make the interpretation of the results a cautious act. With these facts in mind, policymakers are faced with a multi-faceted dilemma in need of fine-tuning.
Culturally diverse college students often have high rates of addictive disorders, yet tend to have lower rates of treatment participation and completion. Much of this is due to the lack of culturally relevant practices and treatment. Collegiate Recovery Programs have been established over time to serve college students in a capacity that reinforces a lifestyle of recovery from substance use and addictive behaviors. This study examines nationwide enrollment and demographic data collected from the 133 Collegiate Recovery Programs operating in the United States. While the 133 Collegiate Recovery Programs are spread across the United States, North Carolina has a number of unique characteristics which separates it from the remaining states. The state of North Carolina was the first state to use public funds to support collegiate recovery. There are currently nine CRPs established at universities within the system, including the sole Collegiate Recovery program operating in a Historically Black College. This study provides more focused analysis of how collegiate recovery program operate in in North Carolina, with a focus on the differences between the collegiate recovery program at a Historically Black College and University (HBCU) and Predominantly White Institutions (PWIs). Overall results indicated that most recovery programs are housed primarily within campus Student Health and Wellness Services. This study’s findings demonstrate that HBCU environment may differ by more often coordinating campus wide participation for recovery events. The implications of integrating the larger community to recovery services allows for greater participation from allies and advocates. This study advances the research in collegiate recovery and provides insight to practice for coordinators, counselors, administrators, and researchers.
In the United States, Black women often face a number of disparities due to historical systems of oppression, social determinants of health and intersecting aspects related to gender and race (Lewis et al., 2016; Thomas et al., 2011; Spates et al., 2020). These factors may affect aspects of physical, mental and spiritual health, thus impacting overall quality of life and wellness outcomes. Wellness is defined as an integrated multidimensional construct (Myers & Sweeney, 2000). Tenets of the theory of intersectionality also apply an integrated framework addressing the unique contributions of intersected identities in the lives of Black women (Crenshaw, 1999). Many bodies of work outline the detrimental effects of systematic oppression and institutional racism on specific aspects of mental health, health and well-being of minoritized populations. However, there is little research focusing on the intersectional experiences of Black women in relation to gendered racism, race-related stress socioeconomic status (SES) and its impacts on total wellness factors. In this study, a non-experimental correlational research design was used with a standard multiple regression to explore relationships between gendered racism, race-related stress, SES and wellness scores amongst Black women. A total of 471women across the U.S. completed an online survey consisting of a demographic questionnaire and three measurements: The Gendered Racial Microaggression Scale for Black Women, Index of Race-Related Stress-Brief and the Five Factor Wellness Inventory. A standard multiple regression analysis indicated that more gendered racial microaggression on certain domains (Assumption of Beauty and Sexual Objectification, Silenced and Marginalized, Angry Black Woman) were associated with higher wellness scores, but other domains (Strong Black Woman) were not. Additionally, higher scores on race-related stress and the lowest SES status group were associated with lower overall wellness scores. Findings from this study highlight the need and importance of examining the intersections of race and gender and their impacts on the lived experiences, health and wellbeing of Black women. Recommendations for future research are provided along with implications for counseling practice and instruction.
This dissertation presents my research on algorithm/architecture co-design of deep spatial and temporal separable convolutional neural networks and their applications. I will introduce DeepDive as a framework for enabling and power-efficient execution of spatial deep learning models on embedded FPGA. For emerging Deep Separable Convolutional Neural Networks (DSCNNs), DeepDive is a fully-functional, vertical co-design framework for power-efficient implementation of DSCNNs on edge FPGAs. Agile Temporal Convolutional Network (ATCN) is also proposed for high-accurate fast classification and time series prediction in resource-constrained embedded systems. ATCN is primarily designed for mobile embedded systems with performance and memory constraints, such as wearable biomedical devices and real-time reliability monitoring systems. It uses the separable depth-wise convolution to reduce the computational complexity of the model and residual connections as time attention machines, to increase the network depth and accuracy. The result of this configurability makes the ATCN a family of compact networks with formalized hyper-parameters that allow the model architecture to be configurable and adjusted based on the application requirements. I also will present DeepTrack and DeepRACE, which are two other aspects of the application of DNN in vehicle trajectory prediction in highways and real-time reliability monitoring of transistors.
In this thesis, we hypothesize that data visualization users are subject to systematic errors, or cognitive biases, in decision-making under uncertainty. Based on research from psychology, behavioral economics, and cognitive science, we design five experiments to measure the role of anchoring bias, confirmation bias, and myopic loss aversion under different uncertain decision tasks like social media event detection, misinformation identification, and financial portfolio allocation. This thesis makes three major contributions. First, we find evidence of cognitive biases in data visualization through multiple behavioral trace data including user decisions, interactions logs (hovers, clicks), qualitative feedback, and belief elicitation techniques. Second, we design five digital experiments with interactive data visualization systems across different design complexities (coordinated multiple views to single plot) and data types (social network, linguistic, geospatial, temporal, statistical) and evaluate them on user populations that range from novice to expert (crowdsourced, undergraduate, data scientist, domain expert). Third, we evaluate the experiments using statistical, probabilistic, and machine learning techniques to measure the effects of cognitive biases with mixed effects modeling, hierarchical clustering, natural language processing, and Bayesian cognitive modeling. These experiments show the promising role data visualizations and human-computer techniques could remediate such biases and lead to better decision-making under uncertainty.
High performance, light weight alloys are need-of-the particularly in the defense, automotive and aerospace sectors. Magnesium is a prime candidate since it is the lightest structural metal having a mass density of 1.74g/cm3 and is the sixth most abundant element in the Earth’s crust. But, as a metal with a Hexagonal close packed (HCP) crystal structure, it exhibits poor formability, yield asymmetry, edge cracking in rolling, and low ductility at room temperature. Activation of non-basal slip planes, suppression of twinning, and promotion of recrystallization mechanisms leading to texture randomization have been a few key strategies incorporated during alloy design to achieve better properties.
In this study, the effect of thermo-mechanical processing i.e., confined rolling on three Mg-Al alloys namely AZ31B, Mg-6%Al and Mg-9%Al was analyzed. Extensive microstructural analysis using advanced electron microscopy techniques revealed the occurrence of either partial (in case of Mg-9%Al) or complete dynamic recrystallization which in turn refined the grain size, improved both strength and ductility under compression and randomized texture. Correlation of rolling temperature, strain rate, %Al content with texture, twinning, recrystallization kinetics, deformation mechanisms, precipitation kinetics and morphology have shed light on creating the best processing route for each of these alloys to achieve optimal microstructure and improved compressive mechanical behavior.
Nature walks have been demonstrated to increase cognitive and emotional well-being by restoring attention and increasing positive affect, both of which are linked to increases in reflective (“broadened") thinking. Broadened thinking is contrasted to the narrowing of thoughts associated with scarcity, the feeling of not having enough resources. This study proposed a model outlining the process by which broadened thinking occurs during nature walks while also incorporating scarcity. One hundred sixty-five college students reporting varying levels of scarcity took at 30-minute outdoor walk. Structural equation modeling demonstrated that the proposed model was a good fit for the data, supporting the hypothesized links between nature, restoration, positive affect, and broadened thinking. Although scarcity did not moderate relationships as expected, ANOVAs showed that participants experiencing the highest time scarcity saw the greatest increases in restoration and broadened thinking, providing some support for the hypothesis that those with more scarcity would derive greater benefit from nature walks. This study demonstrates the effectiveness of nature walks as an intervention, especially for students pressed for time, and highlights the importance of cultivating walk environments that are safe and accessible for all. Implications for future research and interventions at the individual and societal level are discussed.
The field of education relies heavily on instructional coaches to build teacher capacity in the implementation of evidence-based practices (EBPs) with fidelity. Although observation tools are used to measure the fidelity of implementation by teachers, less is reported about specific behaviors demonstrated by a coach. This two-part nonexperimental study used primary and secondary data. It sought to develop a valid and reliable Coaching Observation Tool, and used it to analyze 36 recorded real-time coaching sessions supporting the implementation of an EBP, Targeted Reading Intervention (TRI). The tool was developed using an iterative process of initial coach interview and systematic review of the literature, review of a sample of recorded coaching sessions with the initial draft of the tool, and focus group member checking interview with coaches. Next, the tool was used to analyze a sample of recorded TRI coaching sessions. The coaches in the present study provided coaching to teachers during year 2 of a TRI multi-site randomized controlled trial study. Although the tool was developed and used to identify the frequency with which discrete coaching behaviors were used, the current tool did not demonstrate validity and reliability. The findings suggest this tool could be helpful to identify coaching practices to support the implementation of EBP, such as TRI. Researchers using coaching to support the implementation of EBP alone, or as a component within PD, will find this tool provides them a clearer understanding of the instructional coach in building teacher capacity with the fidelity of implementation of the EBP.
As a result of various academic, behavioral, and social-emotional challenges that adolescents may experience during high school, an alarming rate of students are not acquiring their high school credentials. To address this concern, researchers have suggested dropout prevention efforts should focus on using a comprehensive, preventative, tiered framework such as Schoolwide Positive Behavior Interventions and Supports to target alterable classroom-level variables such as student behavior, student attendance, academic performance, and student engagement. One of the most efficient and effective methods for improving academic engagement and student behavior is through the implementation of evidence-based classroom management practices, such as increasing students’ opportunities to respond (OTRs) during teacher-directed instruction. Unfortunately, many teachers lack adequate amounts of training in these practices. This study investigated the effects of multilevel professional development (PD) and coaching support provided by a school-based coach on high school teachers’ use of a trained classroom management skill (i.e., OTRs) during teacher-directed instruction in a single-case, multiple baseline design across two teacher participants. Overall results showed teachers improved implementation fidelity but failed to achieve the required rates of OTRs. Additionally, when teachers improved implementation fidelity, students also demonstrated increases in active academic engagement. Social validity data indicated teachers and the school’s instructional coach rated the multilevel PD and coaching framework to be moderately effective in supporting teachers’ implementation of high rates of OTRs. Student participants reported observed increases in teachers’ use of a variety of OTRs, positive feelings associated with actively participating in class when presented with increased OTRs, and a better understanding or retention of course content when teachers used high rates of OTRs. Limitations of the study, implications for practice, and suggestions for future research are discussed.
