Electronic Theses and Dissertations

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About: Electronic theses and dissertations (ETDs) are the graduate research outputs of Texas Tech University. They represent years of work from our Master's and Doctoral graduates. If you find the ThinkTech digital repository useful, please tell us! Share how open access to scholarship benefits you. Your story matters to us.

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    Methods of Improving Non-Linearity in Photomultiplier Tubes for Radiation Detection
    (2023-05) Zulhilmi, Haris
    Radiation is a form of energy. There are many types of radiation, but this paper will only discuss one type of radiation, gamma radiation. High exposure to gamma radiation may harm living organisms; hence, it is important that a method to measure gamma exposure is developed. A common way to measure gamma radiation is by using a photomultiplier tube (PMT) with a scintillator. The scintillator converts gamma rays to visible light for the PMT. However, PMT’s can only measure low to medium amounts of light. When measuring high amounts of light, the PMT becomes non-linear, which causes accuracy problems. It is possible to tune the PMT to read high amounts of light, but then it will not be able to detect low amounts of light due to the capability of the electronics to read low amounts of quiescent current with good resolution. This research paper identifies the cause of non-linearity in PMT’s and discusses the possibility of using one PMT with a scintillator to measure low to high amounts of light by solving the non-linearity issues. This research paper will also resolve the issue of measuring low amounts of quiescent current with good resolution to improve detector accuracy. This will improve the radiation detection industry because it will be much easier to perform radiation detection with one PMT that can detect low to high amounts of light without having to tune the PMT depending on the expected light intensity. This method will also help with reducing electronics power consumption for the PMT in gamma radiation detection. These results illustrate that solving non-linearity in PMT’s and the ability to measure low amounts of quiescent current with good resolution is possible, however it will require a little more work to find the right electronic switches to obtain efficient power consumption.
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    An American Port of Call: Score Analysis and Transcription for Wind Ensemble
    (2023-05) Johnson, Pershauna
    The wind band has a history of commissioning and transcribing new pieces for the medium. There is a growing demand for works by underrepresented composers and those that incorporate unconventional soundscapes and experimental techniques. This dissertation focuses on the transcription of Adolphus Hailstork's An American Port of Call, originally written for orchestra, for wind ensemble. The piece is highly regarded and celebrated by the orchestra for its contemporary sound and influences from traditional Romantic music. The analysis of the piece provides insights into its orchestration techniques, timbral variations, texture changes, and harmonic and thematic development strategies. The writing also discusses the rehearsal considerations that can inform the conductor's decisions to ensure a faithful performance of the transcription.
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    From Renaissance to Revolution: Early Modern English Literature in Arabic
    (2023-05) Muhammad, Ahmed N. S.
    This dissertation explores the translation and adaptation of early modern English literature in the contemporary Arabic-speaking world. The works of Thomas More, William Shakespeare, John Milton, and John Donne have been mobilized in the modernist discourse over Arabic poetics and the revolutionary wave referred to as the “Arab Spring”. The dissertation analyzes Bahaa Jahin’s translation of Donne’s Songs and Sonnets, Ahmed Khaled Tawfik’s novel Yutūbyā, Hanna Aboud’s translation of Milton’s Paradise Lost, and Abdel-Rahim Kamal’s screen adaptation of Shakespeare’s King Lear. In their appropriation of early modern literary works, translators, fiction writers, and scriptwriters performed various acts of rewriting that aim to expand and destabilize the poetic inventory, experiment with generic conventions, envision sociopolitical change, reflect on freedom and imperialism, and address regional marginalization. These different agendas highlight the agency of rewriters and the transformative role of translation and adaptation. Moreover, the intertextual discussion of early modern English writings from a contemporary Arabophone perspective provides new critical insights into these writings and discloses new meanings and interpretations.
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    Enabling Context-Aware Natural Language Processing: From Dense Vector Representations to Contextual Features
    (2023-05) Gutiérrez, Luis Felipe
    Natural Language Processing (NLP) is an interdisciplinary approach arose from the intersection of computer science, artificial intelligence, psychology, and linguistics during the early 1940s. Nowadays, NLP approaches are powered by machine learning (ML), which needs a suitable set of features to be effective. In that direction, word embeddings are dense vector representations that are state-of-the-art features in ML-powered NLP applications. Despite the success of word embeddings, researchers have identified important drawbacks. For instance, dense representations limit the interpretability of the results produced by these systems and often neglect the context around constituents in the sentences. This dissertation advances towards context-aware features that remedy the problem of lack of interpretability and context consideration inherent to word embeddings. This is done by first applying state-of-the-art embedding and topic modelling techniques in a non-conventional field for such techniques: economics, specifically to statements issued by the Federal Reserve, while highlighting the problems that word embeddings have. Next, the study uses embedding and ensemble learning approaches in phishing and fake reviews detection to explore if the deceptive intent can be modeled using word embeddings, hence, stepping forward towards the consideration of context in the features. In addition, an evaluation of the performance of content-derived linguistic cues in the task of fake reviews detection is presented. Finally, this dissertation concludes with the presentation of ContextMiner, a novel NLP framework to automatically capture contextual features for extracting meaningful context-aware phrases, i.e., Contextual Features, from cybersecurity texts. The dissertation shows the potential of ContextMiner for Named Entity Recognition (NER), information retrieval, and knowledge systematization using security texts. The study also presents a detailed case study where we perform document clustering using a novel document representation comprised of contextual features. Contextual features can enhance the usability of ML-powered NLP systems by maintaining their explainability, as demonstrated in the results.
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    The Role of Parental Involvement in COVID-19 Pandemic Trauma Recovery in Undergraduate University Students
    (2023-05) Yesil Hafizoglu, Suzan
    University students are more vulnerable to mental health conditions and issues including depression, anxiety, stress, and trauma compared to the general population (Karyotaki et al., 2020). It has been suggested that the coronavirus pandemic amplified the burden on the mental health of university students (Villani et al., 2021). This study explored university students’ traumatic experiences due to the pandemic; and investigated the role of parental involvement in trauma recovery. The research employed a qualitative case study strategy utilizing semistructured interviews and focus groups to collect data. The study sample were 34 traditional undergraduate students at an urban public research university in Texas, United States. The findings from a thematic analysis of transcribed interview and focus group data indicated that participants were directly and indirectly exposed to traumatic experiences related to the COVID-19 pandemic and its impact. The findings included four categories of main themes which were (a) traumatic experiences; (b) reactions to traumatic experiences; (c) trauma recovery; and (d) role of parents in trauma recovery. Parental involvement though emotional connectedness and supportive communication played a key role in participants’ trauma recovery. The study sheds light on the positive impact of parental involvement in promoting mental, emotional and psychological wellbeing of university students during times of adversity. Researchers, policy makers, and practitioners should pay more attention to parental involvement in higher education institutions (HEIs) and embrace it as a critical component of trauma-informed and trauma-specific approaches and interventions in HEIs.
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    Improving Process Flow, Reducing Patient Transfer Costs and Planning Capacity in a Psychiatric Hospital
    (2023-05) Mondal, Pritom Kumar
    Patients who are receiving treatment from outpatient mental health centers, general hospitals, and community mental health centers are sometimes referred to a psychiatric hospital for advanced and around the clock care. However, due to capacity limitations, not all referred patients are able to be admitted to the psychiatric hospital. In order to be admitted, patients must undergo a multiple step admission process and be diagnosed as being severely decompensated. For the collaborating psychiatric hospital, the original referral admissions system resulted in long wait times for patients due to staffing shortages in the admission process leading to delayed access to care and increased system costs. Additionally, due to ineffective assignments of the hospital’s mental health professionals, admitted patients did not receive timely treatment, resulting in inadequate patient care. This created an opportunity for the psychiatric hospital to improve its strategic, tactical, and operational policies to enhance the delivery of patient care. This research examines three research concepts to streamline the process flow, minimize patient transfer costs, and plan capacities within the psychiatric hospital. The first research idea aims to improve the admission process of the psychiatric hospital by addressing delays caused by insufficient capacity in the mental health disorder identification (MHDI) step. Through a discrete event simulation (DES) model, eight MHDI capacity scenarios are analyzed, and it is recommended to increase daily MHDI capacity and provide backup during staff vacations. This results in a faster admission process and annual savings of $1.9 million. The second research idea focuses on reducing patient transfer costs by using telemedicine in the psychiatric evaluation (PE) step. Dynamic decision rules are developed to choose between on-site and telemedicine PE, and a rule-based DES model is used to analyze five operating policies regarding distributing MHTs between on-site and telemedicine PE. This approach results in a 12% reduction in average patient transfer costs. The third research idea concentrates on developing an effective policy for assigning mental health therapists (MHTs) to care units (CUs) to provide timely treatment to patients. The concepts of primary and backup MHTs are introduced to utilize capacity effectively, and a mixed-integer linear programming (MILP) model is developed to determine optimum MHT assignment to treatment CUs. The MILP model also determines which patient in a CU receives which treatment from which MHT in a given week, resulting in an 74% reduction in uncompleted treatments while using the existing number of MHTs.
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    Drivers of plant nutrient acquisition and allocation strategies and their influence on plant responses to environmental change
    (2023-05) Perkowski, Evan A.
    Photosynthesis is the largest carbon flux between the atmosphere and terrestrial biosphere and is constrained by ecosystem biogeochemical cycles. Terrestrial biosphere models exhibit strong divergence in simulated carbon and nitrogen fluxes under future environmental conditions. Divergence across model products may due to the high sensitivity of terrestrial biosphere models to the formulation of photosynthetic processes, coupled with uncertainty in the photosynthetic acclimation response to changing aboveground and belowground environments. Photosynthetic least-cost theory provides a promising framework for understanding such photosynthetic responses to changing environments; however, empirical tests of the theory are rare, limiting our ability to assess whether the theory is suitable for implementing in future iterations of terrestrial biosphere model products. Here, I present four experiments designed to test assumptions of photosynthetic least-cost theory. Experiment chapters are flanked by a general introduction chapter and general conclusion chapter. The first experimental chapter quantifies structural carbon costs to acquire nitrogen in Glycine max and Gossypium hirsutum grown under four nitrogen fertilization levels and four light availability levels in a full factorial greenhouse experiment. I find that carbon costs to acquire nitrogen in both species increase with increasing light availability and decrease with increasing fertilization, though responses to fertilization in G. max were markedly less than G. hirsutum. The second experimental chapter quantifies leaf nitrogen and photosynthetic traits in upper canopy leaves of deciduous trees growing in a 9-year nitrogen-by-sulfur field manipulation experiment. I find evidence for nitrogen-water use tradeoffs with increasing soil nitrogen availability, evidenced through a negative relationship between leaf nitrogen content and ratio of leaf intercellular CO2 concentration to atmospheric CO2 concentration (leaf Ci:Ca) and stronger increase in leaf nitrogen content with increasing soil nitrogen availability than leaf Ci:Ca. The third experiment investigates variance in leaf nitrogen content across a climate and soil resource availability gradient in Texan grasslands, showing that effects of soil resource availability and climate on leaf nitrogen content are driven by changes in leaf Ci:Ca. Finally, the fourth experiment quantifies leaf and whole plant acclimation responses in G. max grown under two atmospheric CO2 levels, with and without inoculation with Bradyrhizobium japonicum, and across one of nine nitrogen fertilization treatments in a full factorial growth chamber experiment. I find that photosynthetic responses to CO2 were independent of soil nitrogen fertilization and inoculation treatment, though the positive effect of elevated CO2 on total leaf area and total biomass was stronger with increasing fertilization and in inoculated pots under low fertilization. Experiments included in this dissertation provide consistent support for patterns expected from photosynthetic least-cost theory. The use of multiple experimental approaches allowed me to examine mechanisms driving patterns expected from the theory and investigate whether these patterns occur in the field across environmental gradients. Findings from these chapters challenge common paradigms in plant ecophysiology, providing empirical evidence suggesting that including photosynthetic least-cost frameworks in terrestrial biosphere models may improve longstanding divergence in simulated carbon fluxes across terrestrial biosphere model products.
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    Influence of 2,4-D on Susceptible Cotton
    (2023-05) Russell, Kyle R.
    With the release of 2,4-D tolerant cotton varieties to aid in the control of glyphosate-resistant Palmer amaranth, the number of postemergence applications of 2,4-D has increased. While 2,4-D and other auxin herbicides have been used for decades in the Texas High Plains in crops such as corn and grain sorghum, they have never been used postemergence in cotton. Field trials were conducted in 2019, 2020, and 2021 to evaluate the influence off-target movement of 2,4-D has on susceptible cotton. Off-target movement of 2,4-D to susceptible cotton can negatively influence boll distributions, lint yield, and fiber quality. The sensitivity of cotton largely depends on both the timing and rate of the off-target movement. Cotton cultivars respond differently to low rates of 2,4-D. Early maturing cultivars were less sensitive to losses than mid-full maturity cultivars. Following off-target movement, nutrient concentrations of nitrogen, phosphorus, and potassium increased in the leaves, stems, burs, and seeds at early application timings whereas later applications did not influence nutrient concentrations. The use of 2,4-D is an effective tool to manage troublesome weeds; however, education on the influence off-target movement has on susceptible cotton is of the utmost importance.
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    Exploring Learned Resourcefulness as a Mitigator for Situational Writing Apprehension: A Post-Intentional Phenomenological Journey
    (2023-05) Millett, Stephanie
    Writing apprehension is a phenomenon that manifests as fear and avoidance of evaluated writing that can affect students’ college and career choices. Writing apprehension has been shown to negatively correlate with self-efficacy, which is one of four forms of learned resourcefulness that have been shown to help an individual maintain emotional control in stressful situations in order to achieve a goal or outcome. The other three forms of learned resourcefulness are delayed gratification, cognitive positive reinforcement, and problem solving. Using post-intentional phenomenology, I explored the ways graduate students in online programs experienced writing apprehension and the ways learned resourcefulness manifested in these experiences. My findings reveal that my participants appeared to be experiencing situational writing apprehension and that they did mitigate it by using learned resourcefulness. By framing participants’ experiences within the post-intentional phenomenological concept of through-ness, I discovered that feedback was a significant contributor or mitigator to my participants' writing apprehension, that online learning did influence their writing apprehension, and that learned resourcefulness did manifest in their experiences with writing apprehension.
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    Optimality Theorems and Numerical Results on Block Preconditioners for Implicit Runge-Kutta Methods for PDEs in Engineering and Biophysics
    (2023-05) Clines, Michael R.
    In this work, the optimality properties of a broad class of block preconditioners for fully implicit Runge-Kutta methods are presented along with various numerical experiments that demonstrate the effectiveness of these preconditioners. For general linear hyperbolic and parabolic PDEs, order-optimality properties of these block pre- conditioners considered are proven for the timestep and spatial discretization size. Numerical analysis of the spectra and fields of values of the preconditioned systems is presented along with numerical experiments that show the performance of the pre- conditioners for improving GMRES convergence rates. Additionally, the preconditioners are shown to be order optimal with respect to timesteps and diffusion parameters for the stage 2 Radau IIA time-integrator ap- plied to stabilized advection-diffusion equations along with additional GMRES ex- periments coupled with numerical analytics of the appropriate spectra and fields of values. A new eigencluster-optimized block-diagonal preconditioner is proposed with a discussion behind the design and implementation of the preconditioners. Numeri- cal results are shown that demonstrate the strength of the optimized preconditioner, which frequently outperformed the established block preconditioners, including the gold standard preconditioner from the existing literature.
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    Exclusionary Discipline Policy Issues in Texas Schools
    (2023-05) Cirino, Angela M.
    This dissertation contains three empirical studies which examine exclusionary discipline policy issues in Texas schools using different datasets and quantitative methods. The first study investigates the disparities in exclusionary discipline consequences for students in special education and whether receiving an Individualized Education Plan (IEP) is associated with changes in exclusionary discipline outcomes for students. The study uses administrative data from a Texas school district. Exclusionary discipline outcomes are broken down by disability type to examine specific disparities and variances. The second study examines whether the implementation of Conscious Discipline affects the frequency of exclusionary discipline outcomes for students in a North Texas school district. The study uses data from three Texas school districts in region 11. The third study investigates to what extent participation in a fine arts enrichment course (art, dance, theater, music) affects a student’s likelihood of receiving exclusionary discipline and being absent from school. This study uses administrative data from a Texas school district. Prior research shows that exclusionary discipline has negative outcomes for students and does not change student behavior. This dissertation affirms prior research and shows that current discipline policies can lead to inequities for students with disabilities and Black students being assigned higher frequencies of exclusionary discipline. This dissertation also investigates options to improve outcomes for students.
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    High-Resolution Near-Surface Wind Analysis with the Weather Research and Forecasting Model
    (2023-05) Wixtrom, Tyler
    Accurate estimates of near-surface winds are essential to a variety of applications, both in real-time and post-event analysis. These estimates are often based on a numerical weather prediction model, which creates a forecast or analysis resulting from a first guess of the atmospheric state integrated forward in time by solving the equations governing atmospheric motion. Traditionally, these forecasts have been produced at spatial scales too large to resolve complex flow near the surface, and near-surface winds have been largely (and inaccurately) parameterized. However, modern computing technology now allows for the generation of real-time forecasts at scales approaching that of the largest eddies observed within the atmospheric boundary layer. As such, it is useful to understand the ability of current numerical weather prediction models to resolve (or parameterize) near-surface winds at grid scales under 4 km. A comparison of model-resolved winds to that observed in the Texas Tech University National Wind Institute 200-m Instrumented Tower is presented. Model configurations varying in horizontal and vertical spacing, output timestep, turbulence parameterizations, and surface parameterizations will be used to assess the current best model configuration for resolving near-surface winds under turbulent conditions. It is also of interest to examine the performance of model simulations for high wind events associated with landfalling tropical cyclones. Observations of four landfalling hurricanes (Laura 2020, Delta 2020, Ida 2021, and Florence 2018) were collected by the Texas Tech University Hurricane Research Team using the StickNet platforms. The best performing model configuration determined by the test case was used to simulate each storm and compared with available observations for accuracy in timing, track, and intensity at landfall. This best configuration was further validated against available observations to assess model performance for near-surface wind variability. Finally, a correction to simulated wind speed based on an Artificial Neural Network was developed to bridge the gap in scale between current model simulated winds and that observed by modern systems. A survey of relevant previous studies, a detailed discussion of the methodology utilized along with results and recommendations for future work are presented.
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    Stupidly Good
    (2023-05) Winfree, Brianna
    My chapbook, Stupidly Good, is about the ancient relationship we have with work. The poems speak about the power of domesticity, solitude, and juxtaposes emotional labor with physical labor. Often, parenthood and questions of familial responsibility rise as the speakers think about the most meaningful kinds of work we can do.
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    College Students’ Communication Apprehension and Adult Attachment Styles on Dating Apps
    (2023-05) Martinez, Ryan J.
    This study analyzed how adult attachment styles affect college students using dating apps. Participants (N= 316) provided responses that resulted in quantitative data regarding how their communication apprehension, dating app usage, and satisfaction when using dating apps play a role in their dating life. Findings revealed that attachment styles affect an individual's communication apprehension when they are on dating apps. Results also indicated that an individual's attachment style influences app usage as a dating app user. Interestingly, attachment styles affect how much satisfaction an individual gains from the relationships they establish on dating apps.
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    “Loving Yourself is Something That's Really Hard to Do ...”: An Interpretive Investigation of Body Image and Body Talk in Interpersonal and Online Relationships
    (2023-05) Brammer, Sydney E.
    This study explores the personal experiences of young women social media users (18-25) and what they perceive as the most salient body image messages and body talk patterns communicated by their families, peers, and social media networks. Participants shared some of their most vulnerable stories about everything from disordered eating and body dysmorphia to peer challenges and perceived generational differences during in-person, one-on-one, semi-structured interviews (n = 20). Then, a thematic analysis of the interview data was conducted, contextualized by literature on the Tripartite Influence Model (TIM), Script Theory (ST), intersectionality, and body ideals. Findings indicate that young women social media users not only feel pressured to adhere to beauty standards that are in line with the enduring thin ideal, but that they feel like there is no end to these messages—it has become a normalized lens through which they critique themselves. The rabbit hole of negative messages on social media only echoes and exacerbates negative messages from friends and family. Results also indicate that body talk scripts are overwhelmingly negative, so much so that positive exceptions to the usual patterns are seen as weird or out of place; these scripts can only be weakened if we pursue a collective deconstruction of fatphobic teachings and the creation of intersectional body talk scripts. Practical and theoretical implications and directions for future research are provided. Please note that this study contains frequent references to serious issues such as eating disorders and suicidal ideation, which may not be appropriate content for all audiences.
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    Audition and Performance Practice for Orchestral Second Trumpet
    (2023-05) Harris, Richard L.
    Much attention is given to orchestral excerpts for first (or principal) trumpet in trumpet training programs. Principal trumpet auditions and first trumpet excerpts receive much more attention and emphasis from educators and performers. By emphasizing these excerpts, a natural void emerges in the general understanding and perception of section trumpet parts. Excerpts for second and other section trumpet parts appear on audition lists for any position other than the first trumpet. Despite this ubiquity, there is limited scholarly literature devoted to these excerpts or this unique role. In my own education and professional expertise on this subject, specific knowledge and performance practice was passed on exclusively through comments made in performance or private lessons. This project involves two distinct parts. The first part is a survey of trumpet players from prominent full-time 52-week American orchestras intended to illuminate varied considerations of the role of the Orchestral Second Trumpet. The second part of the project will be to create audio recordings of orchestral passages featuring the second trumpet in a significant role. This includes many frequently requested orchestral excerpts based on recent audition repertoire for American orchestras with 52-week seasons. These recordings will be in the context of the orchestral trumpet section.
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    The Realizability Question for Algebra Structures on Free Resolutions of Length 3: An Experimental Approach
    (2023-05) Gotchey, Orin
    Ideals in the algebra of power series in three variables can be classified based on algebra structures on their minimal free resolutions. The classification is incomplete in the sense that it remains open which algebra structures actually occur; this realizability question was formally raised by Avramov in 2012. We discuss the outcomes of an experiment performed to shed light on this question: Using the computer algebra system Macaulay2, we classify a billion randomly generated ideals and build a database with examples of ideals of all classes realized in the experiment. Based on the outcomes, we discuss the status of recent conjectures that relate to the realizability question.
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    Examining School Psychologists’ Predictions of Trauma Symptom Identification Self-efficacy using Trauma-Informed Training, Years of Experience, and Provision of Therapy
    (2023-05) Kirkland, Ariel
    The purpose of this study was to examine the relationship between school psychologists’ previous trauma-informed training, years of experience, and direct therapeutic interventions and examine which of these variables is the strongest predictor of trauma symptom identification self-efficacy. Participants were active school psychologists across the United States. Participants completed a demographic questionnaire, the Trauma Training Survey (TTS), a 13-item measure created to assess participants' beliefs that their previous trauma-informed training contained information to help them identify trauma symptoms., and the Trauma Symptom Identification Self-Efficacy Survey (TSISE). The Trauma Symptom Identification Self-Efficacy Scale (TSISE) is a 13-item measure created to assess school psychologists’ beliefs in their ability to identify trauma symptoms. Following data cleaning, a principal axis exploratory factor analysis (EFA) with Promax rotation was conducted to analyze the structure of TTS and TSISE. The finished solution for TTS resulted in a factor structure similar to the developed initial structure, comprised of two subscales that retained 11 of the 13 original items. The finished solution for TSISE did not need to be rotated and retained all original items. Cronbach's alphas were calculated for each subscale and TSISE to assess reliability. Scores for both subscales and TSISE had good internal consistency. Finally, multiple regression was conducted to determine the relationship and predictors between scores on the TTS, years of experience, direct therapeutic intervention and TSISE. There was a significant relationship between both TTS subscales and TSISE and direct therapeutic intervention and TSISE. However, there was no significant relationship between years of experience and TSISE. Results also revealed that the TTSRecognition subscale is the strongest predictor of TSISE and that three of the predictor variables significantly contribute to the overall TSISE model. These findings and implications are discussed in further chapters.
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    Wave-Particle Interaction in Electrostatic Plasma Turbulences
    (2023-05) Ho, Wai Hung
    The stochastic nature of non-resonant acceleration of electrons in one-dimensional electrostatic turbulence is observed in velocity spaces. This stochasticity is found to violate the traditional criterion of resonance overlapping. According to the observation, there are two aspects in the violations: One is that when islands of two adjacent resonances are not mixed, which is there being no overlapping islands, there is still a well-defined diffusion for certain duration of plasma periods; the other is that when field amplitude is far below what overlapping criterion requires, there is stochastic acceleration of particle. A non-Gaussian spectrum of turbulence is studied to foster the understanding of wave-particle interaction. First, in a Gaussian spectrum, electrons escape from the turbulent region in a few plasma periods when this turbulence is strong. This non-Gaussian spectrum can extend the interaction between waves and particles, providing better measurement for resonant transport coefficient. Second, it is attributed to the self-consistency between wave and particle density, particle diffusion modifies field distribution. A Gaussian spectrum then changes into a non-Gaussian one. Statistics of particle diffusion in such a non-Gaussian power spectrum is calculated. The classical Hamilton-Jacobi theory together with the Vlasov theory is applied to present a diffusion coefficient in weak plasma turbulence, while resonance broadening theory is reviewed for strong turbulence. A new diffusion coefficient of wave-particle interaction in the non-Gaussian spectrum is given. These two analytical diffusion coefficients are in good agreement with data obtained in numerical experiments so long as electrons are resonantly interacting with waves within the domain of turbulence.
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    Preserving The History Of A Bi-National Community Through South El Paso Street, El Paso, Texas
    (2022-12) Torres Mata, Laura
    South El Paso Street is a historic-commercial throughfare, that links two border cities: El Paso, Texas and Ciudad Juárez, Chihuahua. This thesis examines how South El Paso Street paved the way for the development of this bi-national community through its urban and architectural transformation. This street was once lined with adobe buildings, soon saw these buildings replaced with new technologies and facades reminiscent of the Midwest. The arrival of the railroad into the Paso Del Norte not only brought a new era of transportation to this part of the United States, but it also summoned new ideas and transformed the architectural fabric of the community. Soon after the railroad arrived, reinforced concrete buildings replaced the traditional buildings of the region. This street tells a story of time, people influences and what the future holds for this resilient community. Downtown El Paso suffered a period of decay beginning in the 1970s and 1980’s. The commercial area that defined downtown was ignored due to the establishment of shopping malls and the city expanding further away from the downtown. South El Paso Street, mainly the section south of Paisano Drive, was especially affected by this neglect. In recent years there have been philanthropic, public, and private economic organizations who have sought to revive downtown. This thesis examines the potential lasting effects of the preservation methods that have been employed and provide recommendations for further rehabilitation of neglected buildings. South El Paso street is still home to many historic and the significant buildings that tell the story of El Paso and can serve as revitalization tools for this area. There is a need for immediate action to reverse the decades-long decline. Improving these buildings, the streetscape, and highlighting their historical place in the life of El Paso, will benefit not only the city, but the people themselves. This will strengthen the commercial and bi-cultural vitality of the entirety of South El Paso Street, which remains an essential link between Mexico and the United States.