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Mi Niñez Nepantlera: The Cultural Journey of a Young Latina
No full textThis project is an autoethnography centered around the topic of Childhood Cultural Nepantla. The word Nepantla comes from the Nahuatl language (informally known as Aztec), which dates back at least 2,000 years. In English, Nepantla translates to “in-between.” For the purpose of this project, Nepantla is applied specifically to culture, which is why I refer to it as Cultural Nepantla. The term Nepantla was introduced to the academic world by the work of Chicana scholar Gloria Anzaldúa. Along with Anzaldúa, other scholars have expanded and brought to light this concept to higher education. However, there is little exposure to Nepantla in children`s literature, which is what motivated me to create a Nepantla children’s book. This project presents a children’s book entitled, “Raquel and the Three Amigos Club.” The book offers a look into the cultural “in-betweenness” that a young Mexican American girl named Raquel faces while trying to live and navigate between both of her cultures. It is important to note that each child lives through their own individual Cultural Nepantla, and this is just one story amongst many. The target audience of my book is Mexican American children between the ages of 6-10 years old. However, it can also be read by parents, teachers, or anyone who wants to understand what Nepantla is and how to explore it.Sociolog
Explaining the Mathematical Expressions Undergraduate STEM Majors Construct to Model Dynamic Scenarios
No full textResearchers and government agencies alike advocate for the inclusion of modeling activities into course curricula K–16. However, educators widely agree that modeling is difficult for students. Within the cognitive perspective on modeling, scholars have conceptualized modeling as a cycle that can be disrupted by inadequately performing key activities. Research conceptualizing modeling in this way produced a list of key activities modelers must perform to transition from one modeling process to another. However, this conceptualization of modeling has not been fruitful for producing compelling, theoretically sound empirical evidence of interventions that support students through their difficulties with modeling. Scholars have shifted to conceptualizing modeling as a cycle that can be disrupted by misalignment between real-world objects and mathematical objects. However, the methodological issue of empirically distinguishing between real-world objects and mathematical objects arises when utilizing that conceptualization of modeling.
My dissertation works towards addressing the theoretical and methodological issue by proposing a novel conceptualization of mathematizing, the process of translating a real-world relationship into a mathematical representation. This novel conceptualization operationalizes mathematizing as a process that can be disrupted by (dis)alignment between the modeler’s mental spaces. Further, my dissertation addresses an empirical need to document modelers’ mental processes that brought about blockages to mathematization.
To meet my goals, I curated data from individual task-based interviews with STEM majors in the southern United States. I tested the applicability of a theoretical framework to accurately capture the modeler’s mathematizing activities using theories on conceptual blending, quantitative reasoning, and symbolic forms. I did this by documenting the quantities and quantitative structures participants imposed onto the scenario, as well as the symbolic forms participants utilized during the task. I then used my theoretical framework to describe instances where participants halted progress while mathematizing in terms of the participants' quantitative reasoning and symbolic forms.
Through my analysis of participants' work, I found that the theoretical framework captured students' mathematizing activities that are occasioned by structuring activities but does not work well to document mathematizing activities that are occasioned by validating activity. In addition, I report three kinds of cognitive obstacles that participants experienced that brought about blockages to mathematizing. My findings have important implications for the teaching and learning of mathematical modeling.Mathematic
Combating Obesity in Minority Children: A Systematic Review on Mobile Health Technology Impacting Healthy Behaviors [paper]
No full textMobile health technology is an evolving approach used to disperse evidence-based methods to improve healthy behaviors. Strategies to combat pediatric obesity are needed, especially among minority children as this population has the highest rates of childhood obesity. This systematic review explores the way mobile health applications may impact healthy behaviors among minority children. A systematic review of literature was conducted utilizing databases, quality appraisal tools, and development of inclusion criteria to uncover a final sample of six studies, which were included in this review. All participants included in the studies reside in the United States of America and the total sample across studies was 2,483. It was hypothesized that mobile health applications would have positive effects on healthy behaviors in minority children. Themes throughout the studies, including the non-importance of mobile application type, improvement of healthy behaviors through utilizing mobile health applications, and the importance of family involvement were identified through this review. The results revealed that mobile health applications can impact healthy behaviors in minority children through increasing physical activity, improving dietary habits, and decreasing body mass index. Although improvements in healthy behaviors were identified, it was also recognized that more research is needed to understand the long-term effects that mobile health applications may have.Nursin
Deep Learning-Based Medium to Long-Term Multi-Step Ahead Wind Power Generation Forecasting
No full textWind energy is crucial for a sustainable energy-powered future, but its intermittent nature poses a lot of operational challenges such as stability and operational issues for the electrical grid. Accurate forecasting of wind power generation is therefore essential to optimize grid operations and effectively integrate this renewable source into the power grid. However, most previous studies in this domain focus on short to medium-term forecasting of wind power generation. Additionally, medium-to long-term forecasting usually utilizes multivariate methods, requiring lots of additional data and computational resources, which might not always be accessible. This research investigates the performance of machine learning algorithms for medium- to long-term wind power generation forecasting using high-resolution historical data. Different time windows (1, 3, 6, 12, and 24 hours ahead) are considered. Statistical and different Recurrent Neural Network algorithms are utilized for univariate time series forecasting. All the neural network architectures are experimented with different hyperparameters to develop the best predictive models. After preprocessing the data, each of the models is trained and tested. The metrics for evaluation encompass mean absolute error (MAE), root mean square error (RMSE), and coefficient of determination (R2). Finally, the trained models are tested on a different dataset to determine their robustness and reliability. The deep learning algorithms are found to be vastly superior to statistical analysis models for forecasting. The findings provide valuable insights into the performance and computational requirements of deep learning models in long-term wind power generation forecasting and contribute to the efficient integration of renewable energy sources and the realization of a sustainable and reliable power grid.Engineerin
Photothermal Modulation of Hydrogels Crosslinked with Dynamic Thiol-Michael Bonds for Biomedical Applications
No full textHydrogels are crosslinked three-dimensional (3D) polymer networks that have tissue-like properties. Dynamic covalent bonds (DCB) can be utilized as hydrogel crosslinks to impart injectability, self-healing ability, and stimuli responsiveness to these materials. In our research, we utilized dynamic thiol-Michael bonds as crosslinks in poly(ethylene glycol) (PEG)-based hydrogels. Because the equilibrium of the reversible thiol-Michael reaction can be modulated by temperature, we investigated the use of thermal and photothermal stimuli to modulate the gel-tosol transition of these materials with the aim of developing a material that could be utilized for on-demand pulsatile cargo release or for 3D cell culture. For this purpose, we incorporated poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles within the hydrogel to facilitate photothermal modulation using near-infrared light. Bovine serum albumin-fluorescein isothiocyanate (BSA-FITC), a fluorescently labeled protein, or doxorubicin (DOX), a chemotherapeutic agent, was loaded into the hydrogel as a therapeutic mimic. Increased release of the mimic cargo upon direct thermal stimulation and photothermal stimulation with an 808 nm laser was observed. However, the hydrogel was found to degrade quickly because of the inherent dynamic nature of the crosslinks. Therefore, we complemented the system with irreversible thiol-maleimide crosslinks to decrease its degradation rate and prolong its functional lifetime. We found that even a small addition of thiol-maleimide crosslinks significantly stabilized the hydrogels but did not cause a notable difference in release at body temperature when compared to the hydrogels lacking the stable thiol-maleimide crosslinks. We also observed better 3D cell retention in the maleimide-modified hydrogels. Altogether, this work advances our understanding of the temperature-dependent behavior of a dynamic covalent hydrogel and leverages that understanding for application as a photothermally responsive biomaterial.Materials Science, Engineering, and Commercializatio
Post Growth Treatment to Improve Electrical Conduction and Physical Properties of Pt-Nanowires Deposited by Focused Electron Beam Induced Deposition (FEBID)
No full textA single electron transistor (SET) is a nano electronic device that works by the quantum mechanical tunneling of single electrons. While SET has promising applications such as ultra-low power logic circuits and qubit readout, the fabrication of SET requires a tiny nanoscale metallic island (a few nm diameter) to be quantum mechanically coupled to source and drain electrodes. The long-term goal of this project is to fabricate an SET by directly writing the required structure (island, source, and gate electrodes) with the focused electron beam induced deposition (FEBID) of platinum on microelectrodes fabricated by lithography. However, FEBID-deposited nanoelectrodes exhibit high resistance because the deposited structures are mixed with unwanted precursor elements like carbon due to its precursor Me3CpMePt(IV), (Me: methyl, Cp: cyclopentadienyl). We study electrical properties of Pt nanowires (NWs) deposited by FEBID technique. We preformed the FEBID deposition in scanning electron microscope (Helios Nano Lab 400). As deposited Pt NWs show high resistance of the order of 100s MΩ. Thus, we investigated the post-deposition processing techniques to turn the deposited NWs into electrically conducting as pure Pt metals. After postprocessing, which reduces the carbon content in the deposition, the processed NWs resistance decreased to 10s ohm. We deposited the NWs with different thickness ranging from 2 nm to 200 nm. The typical length of the NWs is 1 um. The as-deposited NWs can be made much more conductive after annealing in pure oxygen atmosphere. We performed the annealing of the as-deposited NWs at temperature 275◦C in air, resulting in the increase in electrical conductance by five orders of magnitude. The resistances of the NWs are found to be around 10 kΩ after the annealing. In addition to these findings, to our surprise some NWs are as conductive as bulk material, which is something that requires more in-depth study. Length and width dependence of the electrical conductivity and their correlation with the structure of the NWs measured by atomic force microscopy (AFM) and kelvin probe force microscopy (KPFM) are discussed. Energy-dispersive X-ray spectroscopy shows the decrease in carbon concentration after annealing by 90%. Annealing decreases the thickness of NWs to 1/4th the original size.Physic
Development of Alkali-Activated Dolomite Geopolymer as a Carbon-Negative Construction Material: A Comprehensive Study on Carbon Sequestration Potential and Physio-Mechanical Properties
No full textIn response to the escalating environmental challenges posed by the construction industry, this research aims to pioneer a transformative approach in the development of an eco-friendly, green, and sustainable construction material. The research endeavors to develop an environmentally conscious construction material through the exploration of alkali-activated dolomite (AAD) geopolymer as a carbon-negative alternative to the ordinary portland cement (OPC) binder. Harnessing the inherent qualities of natural Dolomite powder (DP) as the primary precursor and integrating Ground Granulated Blast Furnace Slag (GGBFS) as a secondary precursor, this study created a novel construction material with heightened carbon sequestration potential. To initiate the geopolymerization process, a dual activator system with Sodium Silicate (Na2SiO3) and Sodium Hydroxide (NaOH) solutions has been used. The carbon sequestration potential of the AAD geopolymer has been assessed through accelerated carbonation in a pressurized, high-density carbon chamber for 7 and 28 days with 10% CO2 concentration, supplemented by a subset subjected to initial heat activation at 80 º C for 6 hours and subsequent exposure to the carbon chamber. Physical, mechanical, durability, mineralogical, and microstructural properties have been comprehensively evaluated. Physical properties include apparent and bulk density, absorption capacity, and porosity. Mechanical properties were assessed with compressive and flexural strength, and durability was assessed with drying shrinkage. Thermogravimetric Analysis (TGA) has been done to quantify the CO2 sequestration potential, and mineralogical analysis has been done with XRD and XRF. Microstructure and elemental analysis have been carried out with SEM. In the case of 100% dolomite, geopolymerization does not start without heat activation. However, even a small addition of GGBFS kicks off the geopolymerization reaction without the need for heat. AAD with 100% Dolomite with heat activation gives about 32 MPa of compressive strength which is increased by 50% with just 5% addition of slag. Results showed that adding GGBFS significantly enhanced AAD geopolymer's mechanical properties. The AAD geopolymer resulted in an outstanding 28-day compressive strength of 120 MPa with the addition of 40% slag, which increased to 124.2 MPa with heat activation and further increased to 135.1 MPa with accelerated carbonation for 28 days. This outstanding mechanical performance makes the AAD geopolymer a carbon-negative candidate as a lucrative alternative to carbon-intensive OPC binders. Thus, this research not only introduces a sustainable alternative to OPC binder but also underscores its potential as a transformative force in mitigating the construction industry's carbon footprint, paving the way for a greener and more sustainable built environment.Engineerin
Adult Learners' Informal Approach to Mathematical Functions and its Impact on their Formal Understanding of College Algebra
No full textDevelopmental mathematics courses have been recognized as challenging courses for many community college students; hence, more attention has been given to support these learners. Given that a large proportion of these enrolled students are adults it follows that the field of mathematics education should concern itself with their perspectives and experiences. Of particular interest is the informal reasoning adult learners possess as a resource. This study aimed to document and analyze the impact of adult learners’ informal approach to mathematical functions on their formal learning in a community college algebra course. Student reflection upon personal experiences and the implementation of informal strategies was derived from participation in a group activity and analyzed for level of informal engagement as measured using a four-point scale. Linear regression models measured the significance of the task intervention on student achievement as indicated by a written formal assessment as compared to a control group.Mathematic
Relations Between Mother and Child Reports of Adverse Childhood Experiences and Resiliency in Latinx Families
No full textPast research has shown that Adverse Childhood Experiences (ACEs) can have lasting impacts on individuals and family dynamics. However, most research has examined individuals as the unit of study, leaving questions about how ACEs impact parent-child dyads and family relations. Further, little research has focused on ACEs in Latinx families, despite research showing that ACEs are prevalent in individuals in this sample of the population. Thus, there is a need to examine ACEs in parent-child dyads within family dynamics, particularly in Latinx families. The present study investigated relations between mothers’ and adolescents’ ACEs and resiliency among 176 parent-child dyads. Secondary data was gathered by the nonprofit organization Family Service. The measures used were a modified version of the ACEs survey by Family Service and the Brief Resiliency Scale. Maternal resiliency was investigated as a possible moderator between maternal and adolescent ACEs and/or as a moderator between maternal ACEs and adolescent resiliency. Mother’s self-reported ACEs and resilience were positively correlated adolescent’s ACEs and resiliency; however, mother’s resiliency was not found to moderate adolescent ACE nor resiliency. Implications for theory and practice are discussed.Family and Consumer Science
Mitigating the Urban Heat Island Effect in Austin, Texas. It'd Be a Lot Cooler If You Did
No full textThe Urban Heat Island (UHI) effect significantly impacts human-made environments by exacerbating heat-related phenomena such as elevated ambient air temperatures, increased heat index and mean radiant temperature. My research focuses on Austin, Texas, examining how the UHI effect intensifies these heat phenomena and exploring potential mitigation strategies tailored to the city's unique geography and evolving climate. Through a comprehensive analysis, I've identified the specific ways in which UHI exacerbates the heat-related phenomena including the implications for public health and environmental quality. By increasing the amount of impermeable, human-made surfaces throughout Austin such as asphalt and concrete to create housing developments, strip malls, and highway expansion coupled with the increased use of fossil fuels used for things like air conditioning and gas-powered vehicles, we are anthropogenically increasing the temperature of our microclimate. All whilst experiencing an increase in the number of triple-digit days since Austin's weather record-keeping began. My findings suggest that targeted interventions, such as urban greening, reflective material implementation, and equitable planning practices could enhance the city's resilience to heat and promote overall sustainability. Specifically, these planning practices could include an increase in shade to reduce building energy consumption and to provide pedestrian thermal comfort, as well as, incorporate public policies that prohibit or severely limit development along our naturally cooling corridor, the Colorado River. Implementing these solutions could help to foster a more heat-resistant, environmentally conscious, and equitable urban environment, benefiting all residents of Austin, Texas.Geography and Environmental Studie