Recently, 3D printing has received increasing attention for the fabrication and assembly of electrodes for batteries due to the freedom of creating structures in any shape or size, porosity, flexibility, stretchability, and chemistry. Particularly, zinc ion batteries (ZIBs) are favored due to high safety, cheap materials cost, and high volumetric capacity (5,849 mAh/cm3), however, rapid evaporation of Zn due to low melting temperature has limited its 3D printability via conventional laser-based additive manufacturing technique. Here, we develop a printable ink for the fabrication of flexible and 3D printed Zn anode with varied surface areas using the direct ink writing (DIW) method. Our 3D printed porous and high surface area Zn anode structures effectively suppressed the dendrite growth while providing high Zn ion diffusion towards the cathode to significantly enhance the performance of ZIB. By varying filament distancing and path, we 3D printed zinc anode structures with different active surface areas, surface area to volume ratio, porosity, flexible and multiple layer structures that can be incorporated on any device. Carbon in the composite improved conductivity, and mechanical stability of 3D printed zinc anode. Our 3D printed composite anodes allowed flexible designing of batteries surpassing conventional battery designs such as coin cells …

Additive friction stir deposition (AFSD) of AZ31B magnesium alloy was conducted to examine evolution of grain structure, phases, and crystallographic texture. AFSD was carried out using a hollow tool made from tool steel at a constant rotational velocity of 400 rpm on the AZ31B base plate. Bar stock of AZ31B was utilized as a feed material. The linear velocity of the tool was varied in the range of 4.2-6.3 mm/s. The feed rate of the material had to be maintained at a half value compared to the corresponding linear velocity for the successful deposition. The layer thickness and length of the deposits were kept constant at 1 mm and 50 mm respectively. The tool torque and actuator force values were recorded during the process and for calculation of the average input energy for each processing condition. Temperature during the AFSD experiments was monitored using a type k thermocouple located 4 mm beneath the deposition surface at the center of the deposition track. The average input energy values showed a decreasing trend with increasing tool linear velocity. The temperature values during deposition were ∼0.7 times the liquidus of the alloy. The deposited material then was examined by laser microscope and profilometer, …

The interest toward Mars exploration has been considerably increasing due to also the successful deployment of the Perseverance rover and the continuous tests developed by SpaceX's launch vehicle, Starship. While the Mars 2020 mission is currently in progress, the first controlled flight on another planet have been proven in April 2021 with the vertical take-off and landing of the Ingenuity rotorcraft on Mars. In addition, the rotorcraft Dragonfly is expected to achieve the same endeavor in Titan, the largest moon of Saturn, by 2036. Continuous efforts have been oriented toward the development of new technologies and aircraft configurations to improve the performance of current proposed designs to achieve powered flight in different planetary bodies. This thesis work is a preliminary study to develop a comprehensive analysis over the generation of optimum airfoil geometries to achieve vertical flight in environments where low Reynolds numbers and Mach number equal to 0.2 and 0.5.

Air corridors are an integral part of the advanced air mobility infrastructure. They are the virtual highways in the sky for transportation of people and cargo in the controlled airspace at an altitude of around 1000 ft. to 2000 ft. above the ground level. This paper presents fundamental insights into the design of air corridors with high operational efficiency as well as zero collisions. It begins with the definitions of air cube, skylane or track, intersection, vertiport, gate, and air corridor. Then, a multi-layered air corridor model is proposed. Traffic at intersections is analyzed in detail with examples of vehicles turning in different directions. The concept of capacity of an air corridor is introduced along with the nature of distribution of locations of vehicles in the air corridor and collision probability inside the corridor are discussed. Finally, the results of simulations of traffic flows are presented.

Low Earth orbit (LEO) satellite systems have been proposed as a resource for combating the challenges in 5G network coverage and expanding connectivity to a global realm. This research focuses on the current architecture of LEO satellite constellations, with an emphasis on satellite coverage, visibility patterns and coordination schemes. Key-elements of integrating LEO satellites into the eMBB component of 5G are presented and a breakdown of potential link channel characteristics and physical layer performance metrics are described. The produced information allows for a justified analysis on the conceptualized integration.

Compared to other examples of human behavior, humor responses have received relatively little attention from the scientific community and by the behavior analytic community in particular. This study investigated what some of the controlling variables for humans to emit a humor response may be. Participants were randomly presented two types of word sequences/jokes: one with a matching punchline and one without a matching punchline. Participants rated whether the jokes were funny or not funny, and reaction time was measured for all stimuli presented. Generally, the results showed that reaction times to punchlines rated as not funny were shorter than punchlines that were rated funny. These differences in reaction time were interpreted with priming, intraverbal control, and multiple control as an experimental foundation. Limitations include the absence of physiological measures due to COVID-19 restrictions and the forced choice of two rating responses. The implications of this research reveal opportunities for future research of humor responses.

All street hawkers are not the same in many Newly Industrialized Countries (NICs) of the global south as often portrayed by the media and documented in extant literature. This perception has created a gap in knowledge as researchers explore street hawking activities in NICs. In this study, I investigated a new informality trend of street hawking is coming into being within the capital city of Accra, Ghana. As governance is increasingly becoming entrepreneurial, informal activities are gradually becoming formal. Formal and registered businesses are increasingly capitalizing on hawking activities to occupy public spaces. The advent of the informality trend, I term corporate street hawking opens up new issues for the political economy, labor, and urban studies. By employing semi-structured interviews with 47 street hawkers in Accra, this paper sought to investigate three broadly interrelated questions. First, how do neoliberal policies impact the production of public space in Accra? Second, is corporate street hawking a form of creative destruction? Finally, how do corporate street hawkers practice agency within Accra?

Establishing effective language intervention for those who struggle to acquire it early on has received significant attention from researchers within the field of behavior analysis. The procedures of the present study were adapted from Spurgin' thesis research from 2021, in which a stimulus specific consequence was used during teaching after participants made correct responses. In this case, the stimulus specific consequence was a label for a picture that participants were required to point to during teaching trials. When participants pointed to the correct card, the researcher would label the card and deliver a small wooden block which the participants were told they were working for. In the hear-say procedures, participants were taught one set of cards and instructed to echo the researchers' labels. In the see-say participants were taught a second set of cards and instructed to "beat' the researcher to saying the word. After all cards were taught, were tested with a non-vocal receptive identification test. Immediately following this, participants were tested with a vocal expressive identification test. An extended teaching was included to determine the effects of additional practice within each condition. Results indicated that the participants were able to require some receptive and expressive language but targets …

In this study, I examine how self-reported religiosity predicts political opinion toward abortion and gun control. In particular, I examine how self-reported religiosity relates to individuals' inconsistent attitudes on these two issues where liberal attitudes are held toward one issue, but conservative attitudes are held toward the other. Most commonly, these inconsistent attitudes are found among individuals who hold pro-life (conservative) and pro-gun control (liberal) views. Using data from the 2018 General Social Survey, I find that religiosity significantly predicts these inconsistent attitudes regarding abortion and gun control. This suggests that religious ethics regarding life and death can offer a partial explanation for inconsistent attitudes toward partisan issues.

This study was a replication and an extension of the 2021 research performed by Spurgin and Borquez on the correspondence between receptive and expressive behavior. Spurgin examined the role of the echoic in a hear-say procedure with adult learners, while Borquez examined the role of the echoic in both hear-say and see-say procedures. Both studies found that receptive and expressive correspondence did not occur consistently across participants. The present study asked if the fading steps used during training contributed to the results of the previous researchers. In the present study, the fading steps were changed to minimize the chance that the participant developed a position bias. The conditions were also counterbalanced to analyze the effects of hear-say vs. see-say, easy vs. difficult words, and the order in which the words were trained on the acquisition of receptive labels and the emergence of expressive labels. The study consisted of five phases: pre-training, hear-say teaching, see-say teaching, receptive testing, and expressive testing. Results indicated that although that acquisition of receptive labels improved, the change in fading steps did not make a significant difference in the correspondence of receptive and expressive language. Results showed similar correspondence in the hear-say and see-say procedures. Easy …

A projective plane tropical curve is a proper immersion of a graph into the real Cartesian plane subject to some conditions such as that the images of all the edges must be lines with rational slopes. Two important combinatorial invariants of a projective plane tropical curve are its degree, d, and genus g. First, we explore Gathmann and Markwig's approach to the study of the moduli spaces of such curves and explain their proof that the number of projective plane tropical curves, counting multiplicity, passing through n = 3d + g -1 points does not depend on the choice of points, provided they are in tropical general position. This number of curves is called a Gromov-Written invariant. Second, we discuss the proof of a theorem of Mikhalkin that allows one to compute the Gromov-Written invariant by a purely combinatorial process of counting certain lattice paths.

This was a mixed-method user-centered study regarding the University of North Texas's student-owned learner record and credentialing system. Through methods of quantitative and qualitative inquiry, student perceptions were unearthed and recommendations to improve the system were provided.

Multiple contributors to neurocognitive impairment in individuals with sickle cell disease have been identified. Research indicates that a history of cerebrovascular accidents, such as silent infarcts and strokes are associated with greater cognitive decline among children with sickle cell disease. Additionally, disease effects such as hemoglobin and hematocrit levels significantly effect cognitive performance among this population and should be taken into consideration when examining neurocognitive impairment. Further, previous studies show a significant relationship between child behavior problems, family functioning, and cognitive performance in children with sickle cell, marking those as important targets for intervention among this population. While cognitive decline with increased age is not typically examined in healthy child populations, some research indicates the presence of age effects in those with SCD. A majority of the literature addresses cognitive impairment from a broad perspective, while a limited number of studies have begun to address effects among specific cognitive domains. Using archival data from the National Institutes of Health's Cooperative Study of Sickle Cell Disease, results revealed that disease severity was negatively correlated with some aspects of cognitive functioning, including visual-spatial domains. Additionally, some measures of cognitive performance were inversely correlated with age. Consistent with hypothesized outcomes, family functioning was …

Autism spectrum disorder (ASD) presents with difficulties in social communication, repetitive and/or restricted behaviors, as well as variable language development. Individuals with suspected ASD ideally participate in assessments which include measures of cognitive abilities, adaptive functioning, language functioning, and ASD specific measures (i.e., ADOS, ADI-R). Diagnosis of ASD can occur confidently at 2 years of age, however, the mean age at diagnosis is 4-5 years old. Delays in diagnosis are accounted for by lacking professionals and centers with the capabilities to assess ASD, as well as long waitlists for assessments. Early identification and intervention have been shown to provide the best improvements in ASD symptomology. The aim of the current study was to conduct a program evaluation of an autism treatment center that was designed to provide high quality evidence-based interventions. The study determined if treatment-as-usual in that center yields the expected gains in adaptive functioning and corresponding decreases in barriers to learning. Results indicated improvement in scores on standardized direct assessment of milestone achievement and barriers to learning, but no significant improvement in adaptive skills via secondary informant questionnaire measures following 6 months of treatment. The overall sample size was small due to COVID-19 complications, lack of institutional procedures, …

This thesis attempted a cross-species replication of Bland, et. al., 2018. Human participants went through a computerized, automated shaping procedure that trained them to click on and discriminate between a blue square (SD) and red square (S-delta) on a VR 12 schedule of reinforcement. Three conditions were then presented to the participants consisting of a baseline, punishment, and control condition. In the punishment and control conditions, the SD was replaced by the S-delta or a novel stimulus respectively for 1-second on a VR 5 schedule. With each click, the reaction time and specific object clicked on were recorded. While the present study partially replicated the effect seen in earlier research, our results suggest that, depending on the lens of analysis used, either a punishment or an extinction effect may be causing the results seen.

Digital language archives are used for the preservation of documented language data, such as video and voice recordings, transcriptions, survey data, and ethnographic fieldnotes. This data is most often used for research and linguists and anthropologists are generally heavily involved in the creation of language archives. Ideally, Indigenous communities that are represented in the archives are also able to access their data, but this is not always the case, especially if poor internet access and lack of technological know-how prevent archive use. In addition, western epistemologies are embedded in archival logics, exacerbating the issues surrounding Indigenous access and pointing to the need for a decolonizing archival design that centers the needs of its users. Using ethnographic research methods and a decolonizing framework, I conducted a usability study on the Archive of the Indigenous Languages of Latin America (AILLA) to uncover the cultural-based meanings that inform AILLA use. Using linguistics and anthropology listservs, I recruited research participants for a Qualtrics survey and conducted semi-structured interviews that explore the user perspective on AILLA. I analyzed AILLA's Google Analytics data and used qualitative and quantitative research methods to build upon the previous literature in user-centered design approaches to language archives. As one of …

This thesis is a critical analysis and creative commentary providing research and insight into my 150-minute multimedia exhibition, "Femininity: Ownership and Power," that premiered October 23, 2021. All of my research, composition, and collaboration efforts seek to recontextualize the semiotics of ‘femininity' through ownership and empowerment from varying intersections and identities. The titles of the eight works composed and premiered as part of the exhibition include: a beautiful reckoning; Dust; Moirai; Gaia; Portrait of the American Woman; Shared, In Balanced Contrast; At My Intersection; and I See You. Also included was #pinkcode, an exhibit that features a fuschia graphic user interface for an interactive modulation synthesis application built in Csound designed to bring femininity into computer music spaces. The musical compositions vary in instrumentation including flute, alto flute, voice, guitar, viola, harp, cajon, vibraphone, live electronics, and fixed media. They also vary in medium including live performance, virtual reality video, music video, audio-reactive TouchDesigner video, immersive text projections, light show, and live dance. Feminist texts by women poets and authors recited by women personally connected to me are also included in the fabric of the musical fixed media of multiple pieces in the thesis exhibition. Collaborators of artistic media including …

Yttria stabilized zirconia (YSZ) is a polymorph with possible phase transformation toughening occurring during impact. The fractography and mechanical properties of laminated alumina and YSZ were studied in this thesis. Five sample types were studied in this thesis: (5:5) Al2O3/YSZ (a sequence of 5 alumina tapes stacked on 5 YSZ tapes), (5:5) Al2O3/YSZ (1 wt.% Pure ZrO2), (7:3) Al2O3/YSZ, Al2O3, and YSZ. Scanning electron microscopy (SEM) and X-ray microscopy (XRM) were used to study morphology and crack propagation with three-point tests performed to study the flexural strength. X-ray diffraction (XRD) spectra of all samples pre and post three-point tests were examined to determine if a change in monoclinic zirconia occurred. The combination of SEM and XRM data found microcracks in the YSZ layers of Al2O3/YSZ laminates with none present on YSZ laminates, leading to the conclusion tensile stress was performed on YSZ during sintering with Al2O3. Fracture patterns show a curving of cracks in Al2O3 layers and abrupt, jagged breaks in YSZ layers with crack forking at major YSZ microcrack regions. YSZ laminates were found to have the highest average flexural strength, but a very high standard deviation and low sample count and Al2O3 laminates having the second highest flexural …

This study implemented a GIS-based analysis of local climate zones (LCZ) in Denton, TX with data sets from 2009, 2011, 2015, and 2016. The LCZ scheme enables evaluation of distinct regions' thermal characteristics with greater granularity than conventional urban-rural dichotomies. Further, the GIS-based approach to LCZ mapping allows use of high-resolution lidar data, the availability of which for the study area enabled estimation of geometric and surface cover parameters: height of roughness elements, sky-view factor, and building surface fraction. Pervious surface fraction was estimated from National Landcover Database impervious imagery. A regular grid was used to estimate per-cell mean values for each parameter, and with a decision-making algorithm (if/then statements) two maps were produced (2011 and 2015) and six LCZ identified in each: LCZ 6 (open low-rise), LCZ 8 (large low-rise), LCZ 9 (sparsely built), LCZ A (dense trees), LCZ B (scattered trees), and LCZ C (bush/scrub). Post-processing was carried out to ensure identified zones met the spatial minimum for qualification as LCZ. Landsat Collection 2 Level 2 surface temperature products from various seasons of 2011 and 2015 were acquired to examine LCZ thermal differentiability, and preliminary surface urban heat island intensity values were estimated. Particular attention was afforded to …

Broadly defined, group testing is the study of finding defective items in a large set. In the medical infection setting, that implies classifying each member of a population as infected or uninfected, while minimizing the total number of tests.

Disaster science is a procedural field often construed as producing blanket policies that attempt to cover everyone, but the complexity of human lived experiences must have a space to exist within disaster science if its research and findings are to be effective. This thesis illustrates that disaster policies and publications often leave out the most vulnerable communities—those in greatest need of collective support. Through critically analyzing beautification through green space, discussing photovoice interviews, and by deconstructing public preparedness documents published by Harris County Office of Homeland Security and Emergency Management (HCOHSEM), it is clear that accumulation by dispossession filters down through not only property and money but also access to green spaces and a healthy life. By dispossessing low-income communities of their right to green spaces and life, those communities end up in places that are environmentally dangerous, leaving them at a disadvantage in the disaster preparedness and recovery process. This thesis serves as a case study highlighting how HCOHSEM failed to provide low-income communities with assistance prior to, during, and after Hurricane Harvey. The lessons from these gaps in protective measures show that public policies need to be malleable to ensure residents of any community are covered. Though no …

In this paper, I sought to identify and develop a protocol on electrode arrays as a result of rapid aging by applying rapid current over time. We, however, apply a different approach by using phosphate buffer solution (PBS) to mimic the conditions of the body. Here we have established an in vitro protocol for accelerated aging, a process that involves testing in extreme conditions such as oxygen, heat, sunlight, humidity, and vibration aimed at speeding the normal aging process of items; on commercially available shape memory polymer electrode arrays from Qualia over a period of 30 days in PBS. Two electrode arrays were placed in 37°C and 2 were placed in 57°C. Open lead electrochemical impedance spectroscopy (EIS) was conducted on the electrode arrays. Overall, the results showed there were differences in average impedance during this accelerated aging protocol. At 37°C we see that the average impedance values increased as the electrodes were aged at 1kHz from an average of 4.15E6 to 9.14E6 Ohms. At 57°C electrode arrays 4 and 5 showed strong P values well above 0.05, but average impedance increased drastically from 3.27E6 to 9.97E6 and P value of 0.04 from measurement day 24 to day 30. This …

The purpose of this study was to investigate the effects of Pb and hypoxia co-exposure on Pb toxicity and Ca homeostasis in early life stage (ELS) zebrafish (Danio rerio). Previous evidence indicates that exposure of ELS zebrafish to hypoxia (~20% air saturation) reduces Ca uptake, likely through down-regulation of the apical epithelial Ca channel (ECaC). Considering that Pb and Ca are known antagonists and compete for uptake pathways, it was hypothesized that co-exposure of Pb with hypoxia would decrease Pb toxicity by reducing Pb uptake (likely mediated through a reduced number of ECaCs). However, it was shown that at 96 hpf, whole body accumulation of both Pb and Ca was lower at 40% air saturation compared to 100% and 20% air saturation. This result closely aligned with the 96h LC50 results which showed the highest mortality of zebrafish at 40% compared to the other air saturation levels. This suggests that toxicity is likely the result of exacerbated hypocalcemia at 40% air saturation due to both Pb competition for Ca binding to Ca uptake channels/transporters, such as ECaC, and potentially reduced expression of such channels/transporters in response to this level of hypoxia. Overall, it appears that ELS zebrafish respond differentially to …

Historical dress as a museum theater and research process encompasses material, technological, and cultural experiences from the past in the present. This research examines how intimate experiences with heritage materials, processes, and environments may impact development of educator pedagogy. Historical attractions in the US draw visitors due in part to providing guests with context for the objects and built environments displayed. New Materialist theory offers insights into how inanimate objects and environments "teach" human and non-human entities in their own right. Using a New Materialist lens, I observed, interviewed, and conducted participant observations through a novel research methodology, intra-active narrative inquiry, with costumed museum educators to better discern how relations between humans and historical materials intra-act as embodied experiences of object knowledge in museum pedagogy.