A Project in Humanizing Inquiry (San Pedro & Kinloch, 2017), this qualitative dissertation study combined in-depth interview with a LatCrit framework to story the journeys of three Latinas into teaching. Data analysis underscored the layered racialized systems of oppression that marked the three women’s educational identities and professional trajectories. Notable forms of oppression included deficit-laden interactions within schools and schooling that largely predicted the individual women as failures. Likewise, much more intimate familial messaging framed teaching as a dead-end career. With the support of key mentors and through their own determination, the three women, nevertheless, were able to make sense of who they were, what they valued, and the teachers they would ultimately become. Implications for diversity-oriented teacher education and research are presented.
The motivation of this research is to build systems that precisely control displacement in the presence of external load (both linear and rotation force). To achieve this, two experimental platforms have been created. Those instruments incorporate actuation stages, rotary apparatus, and rotary encoder and displacement sensors. During experiments the temperature of the stage and the environment are recorded. Characterization of these processes necessarily requires generation and monitoring of forces and measurements of displacement, rotation, and environmental temperature. The actuator methods include thermal expansion and piezoelectric (PZT) actuation, and the displacement sensing includes optical knife-edge and capacitive gage sensors, and the rotation sensing includes digital camera and rotary encoder. An automated control strategy comprising PID closed loop control (for heating) and On/Off switching between air and mist control (for cooling) is described for the thermal expansion actuator. The translation stage of this study produces a displacement range of 100 µm and 200 µm (using 240 W and 480 W power sources) in the presence of preloads up to 1 kN. Depending on the power source used, the root mean square (rms) controller error at steady-state is within 15 nm (240 W) and 35 nm (480 W). The PZT actuation stage has a displacement range of 16 μm with a resolution of sub-nanometer, and this is used to generate a penetration force between a sample and a diamond indenter tip and this force passes through, and is measured by the load-cell stage. Numeric experiments have been performed with penetration depths from 200 nm to 2000 nm and with penetration forces between 20 mN to 200 mN.
Sports plays a unique role in American culture, acting as a source of entertainment and community identity. It is also a microcosm of society that simultaneously reflects and guides cultural and racial difference. Those differences are illuminated by the journey of the African-American athlete as “large numbers of Americans across racial lines interact with sport and are impacted by its remarkable racial dynamics (Hartmann, 2000, p. 231). The media depictions of Black athletes as super-human, aggressive bodies that are products of poor, blighted and dangerous neighborhoods have created a dominant humble beginnings narrative that stigmatizes Black athletes and marginalized neighborhoods – creating an imagined Black sense of place and space that travels with the athletes as they move from city to city for their professional careers. Grounded in Black Geographies, this research intersects race, the media-framing of male athletes, and neighborhood stigma, providing a new lens through which to evaluate marginalized communities. This research also disrupts the dominant narrative by de-centralize the Black body and offering variations of the lived experience as shared by 30 Black NFL players. Understanding alternate storylines creates new imaginaries of marginalized Black communities and what is needed to improve the quality of life. It concludes with a consideration that scholars and journalists highlight variations of the humble beginnings experience and share the stories of Black athletes who do not come from humble beginnings to help deconstruct racial and geographic stigmas.
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.
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.
This dissertation utilizes a three article approach to examine the current status of psychiatric boarding in the emergency department (ED). The number of ED visits for mental health concerns in the United States has been increasing for the past several decades as the number of inpatient psychiatric beds has decreased. This has created a psychiatric boarding crisis where patients are waiting in ED for extended periods of time across the country. This dissertation provides a 360° view of psychiatric boarding in the ED by critically examining the literature surrounding the effects of psychiatric boarding, analyzing the characteristics of patients undergoing psychiatric boarding through a large national dataset, and by analyzing mixed methods data from ED nurses who care for these patients.
The first article presents a systematic review of the status of psychiatric boarding while also addressing the involvement of civil commitment during a psychiatric boarding stay in the ED. Boarding times in the selected 31 articles varied greatly and patients were rarely started on new psychiatric drugs while in the ED. Common diagnoses for patients included suicidal ideations or suicidal behaviors.
The second article presents an analysis of the 2016-2017 combined Healthcare Cost and Utilization Project Nationwide Emergency Department Sample. Patients that had a psychiatric evaluation in the ED were considered at risk for psychiatric boarding. Patients that boarded for longer than one calendar day and had a psychiatric evaluation were compared to patients that had a psychiatric evaluation but it not ultimately board. Patients that boarded had a greater number of billable procedures performed compared to patients that did not board. The two most common diagnoses of patients undergoing psychiatric boarding for greater than one calendar day were obstructive pulmonary disease with major complication or comorbidity and diabetes.
The final article utilizes data gathered from ED nurses about their experience with psychiatric boarding at their hospital. Nurses that had greater positive attitudes toward patients undergoing psychiatric boarding were associated with greater perceived competency for providing care for persons with mental illness, and fewer stigmatizing attitudes of patients with mental illness. Through a mixed method approach, this study found that nurses perceptions of psychiatric boarding as a problem varied greatly as well as the different practices that can occur during a psychiatric boarding stay. Suggestions for improvement centered on improving the physical environment because of the high pressure and chaotic nature of the ED.
Overall, the details about what occurs during psychiatric boarding in the ED are still poorly described. The lack of research on the short-term and long-term effects of spending extended periods of time in the ED is also concerning, given that this dissertation found that 54.55% of nurses believe that psychiatric boarding is currently a problem at their hospital. Future research that focuses on creating a best practices protocol for patients spending more than 24 hours in the ED is greatly needed to improve the experience and safety of psychiatric boarding for both patients and ED staff members.
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.
