Digital Commons Network^™

Hardware Development And Testing For Lox/Lch4 Rocket Engine, Pedro Nunez

Open Access Theses & Dissertations

The University of Texas at El Paso (UTEP) Center for Space Exploration and Technology Research (cSETR) has focused its research efforts on developing LOX/LCH4 propulsion systems. As part of the Janus Sub-orbital vehicle program, UTEP is developing a 2000 lbf throttleable rocket engine (Chrome X). The first iteration of this engine design will be geared for further optimization towards a flight engine. Components like electric motors, valves, and sealants have been selected to achieve throttle ability and sealing of the engine. These components play a crucial part on the engine to be able to have a successful firing. As part …

Machiavellianism And Endorsement Of Appeal Type: An Examination Of Organization Recruitment, Steven M. Mueller

Open Access Theses & Dissertations

Machiavellianism is characterized by a cynical worldview, a relativistic ethical orientation, and a willingness to manipulate others. Because those higher in Machiavellianism are successful at obtaining positions of power, research is needed to better understand the ways these individuals influence others' attention and behavior. This study examined the effect of Machiavellianism and related personalities narcissism and psychopathy on appeal type preference (guilt-based, ego-promoted, or neutral). In this study, Machiavellianism was not associated with appeal type preference. Those higher in psychopathy, however, were more likely to endorse guilt-based persuasiveness. Further, those higher in narcissism reported positive attitudes toward the recruitment statement. …

Empathic Experience Design For Cognitive Impairment, Leonardo Orea-Amador

Open Access Theses & Dissertations

Empathic Experience Design (EED) is a technique that lets product designers empathize with their product users with the use of empathic experiences. These empathic experiences are activities that let designers become immersed in a simulation of the users' typical environment and conditions and gain powerful insights of the user's product experience. The simulation uses "tools" like earplugs and gloves that can simulate specific conditions such as hearing loss, or lack of sensitivity, for example. Literature shows that this empathic approach enables designers to discover unarticulated customer needs known as user latent needs. Latent needs produce significant benefits in the creation …

Her, Alessandra Narvaez-Varela

Open Access Theses & Dissertations

N/A

A Value-Based Case Study To Increasing Community Mentoring In Stem For Hispanic Students, Gilberto Moreno

Open Access Theses & Dissertations

This case study investigates the implementation of a unique community-driven mentoring pilot program (PASOS2) forging stronger community and K-12 partnerships. Focused on surfacing what matters most in engaging community mentors, this case study explores a civic organization'?s quest to impact, expand, and bring value via mentoring to Hispanic students' pursuit of post-secondary studies with emphasis in STEM careers. A major stumbling block faced by many underprivileged students is the lack of mentorship vital to expanding their social capital support system. This innovative mentoring approach provides students with critical access to STEM community empowerment agents supporting aspiring students' dreams.

Analytical methods …

The Influence Of Multiple Representations On Secondary Students' Understanding Of Trigononetric Functions, Mayra Lizeth Ortiz Galarza

Open Access Theses & Dissertations

Trigonometry is a critical subject in mathematics that both high school and undergraduate students need to learn in order to be prepared for advanced mathematics. Despite the importance of trigonometry in the mathematics curriculum, little is known about best practices for teaching trigonometric functions and what difficulties students face when learning the topic. Using a Grounded Theory approach, this Dissertation presents the results of a design study (or teaching experiment) whose purpose was to examine the process by which students constructed the concept of trigonometric functions through multiple representations and how students developed meta-representational competence. The design study involved two …

The Development Of A Drinking-Specific Compensatory Health Beliefs Scale, Sandra L. Oviedo Ramirez

Open Access Theses & Dissertations

The present study sought to investigate the applicability of the Compensatory Health Belief (CHB) model in relation to drinking by developing and validating the Drinking-Specific Compensatory Health Beliefs (CHBs) Scale in adults between the ages of 18 and 29 living in the United States. In phase 1, a pool of 41 items was administered to 293 undergraduate students. An Exploratory Factor Analysis (EFA) was used to construct the Drinking-Specific CHBs Scale, which consists of 13 items that encompass four different factors - physical activity, no consumption of other drugs, amount of alcohol consumed in future, and rest. In phase 2, …

Combining Interval, Probabilistic, And Other Types Of Uncertainty In Engineering Applications, Andrew Martin Pownuk

Open Access Theses & Dissertations

In many practical application, we process measurement results and expert estimates. Measurements and expert estimates are never absolutely accurate, their result are slightly different from the actual (unknown) values of the corresponding quantities. It is therefore desirable to analyze how this measurement and estimation inaccuracy affects the results of data processing.

There exist numerous methods for estimating the accuracy of the results of data processing under different models of measurement and estimation inaccuracies: probabilistic, interval, and fuzzy. To be useful in engineering applications, these methods should provide accurate estimate for the resulting uncertainty, should not take too much computation time, …

An Investigation Of In-Session Client Change Language And Stage Of Change, Reyna Patricia Puentes

Open Access Theses & Dissertations

In the practice of Motivational Interviewing, recognizing language is important for understanding where a persona stands in terms of readiness to change when considering a behavior change, such as risky alcohol use. Few studies have examined relationships between language expressed in a BMI and survey measures of stage of readiness to change. The purpose of the present study was to evaluate the types of client language in a single BMI session and associations with stage of change among a sample of emergency room/trauma department patients screened for positive BAC and/or risky alcohol use (n = 196). Using structural equation modeling, …

Analysing The Effects Of Data Augmentation And Free Parameters For Text Classification With Recurrent Convolutional Neural Networks, Jonathan Quijas

Open Access Theses & Dissertations

Convolutional neural networks have seen much success in computer vision and natural language processing tasks. When training convolutional neural networks for text classification tasks, a common technique is to transform an input sequence of words into a dense matrix of word embeddings, or words represented as dense vectors, using table lookup operations. This enables the inputs to be represented in a way that the well-known convolution/pooling operations can be applied to them in a manner similar to images. These word embeddings may be further incorporated into the neural network itself as a trainable layer to allow fine-tuning, usually leading to …

Study Of Electron Gas On A Neutron-Rich Nuclear Pasta, Enrique Ramirez-Homs

Open Access Theses & Dissertations

This study used a classical molecular dynamics model to observe the role of electron gas on the formation of nuclear structures at subsaturation densities (Ï?<0.015 fm^-3) and low temperatures (T< 1MeV ). The simulations were performed by varying the Coulomb interaction strength on systems of isospin symmetric and asymmetric matter with periodic boundary conditions. The effect was quantified on the fragment size multiplicity, the inter-particle distance, the isospin content of the clusters, the nucleon mobility and cluster persistence, and on the nuclear structure shapes. The existence of the nuclear pasta structures was observed even with the absence of the Coulomb interaction but with a modication of the shapes formed. It was found that the presence of the electron gas tends to distribute matter more evenly, forms less compact objects, decreases the isospin content of clusters, modies the nucleon mobility, reduces the persistence and the fragment size multiplicity, but does not alter the inter-particle distance in clusters. The degree of these effects also varied on the nuclear structures and depended on their isospin content, temperature, and density.

Safety Airway For Small Unmanned Aerial Vehicles Using A Gas Particles Behavior Analogy, Pablo Rangel

Open Access Theses & Dissertations

The United States Federal Aviation Administration (FAA) implemented the Part 107 legislation to allow the flight of Unmanned Aerial Vehicles (UAV) for commercial use (i.e. package deliveries, power transmission line inspections, etc.) in the National Airspace System (NAS). As a consequence of the newly introduced rules, there is an increased risk for accidents involving injured bystanders or damaged to property. The work within this document defines a UAV to UAV safety distance model that acts as a range sensor enabled "elastic bubble". The length of the UAV safety bubble contracts and expands upon changing airway wind speed conditions. It also …

Healthcare Utilization Awareness And Labor Monitoring Methodology: A Theoretical I.M.S.E. Approach To Risk Minimization And Human Metrics Capturing In The Nursing Workforce, Luis Reyes

Open Access Theses & Dissertations

The healthcare industry is so complex and dynamic that the development of any tool designed to promote positive patient outcomes nearly requires the developer to be an actual healthcare practitioner. Many healthcare tools exists that initially give the perception that there will be no future requirements that may hinder the tools' integrity, but more often than not, the unexpected occurs. The future is one unpredictable element of life that most engineers wish they could capture with optimal precision. I.M.S.E. (Industrial, Manufacturing and Systems Engineering) applications do not assist with fortune telling, but they do assist with creating robust tools designed …

Three Dimensional Finite Element Model For Residual Stresses In Parts Manufactured By Slm And Ebm, Jesus Gerardo Reyes Schuldes

Open Access Theses & Dissertations

Ongoing research efforts in industry and academia have a focus on optimal build parameters that lead to suitable mechanical properties with minimum defects in parts manufactured by powder bed fusion additive manufacturing technologies, such as Electron Beam Melting (EBM) and Selective Laser Melting (SLM). Additional and significant resources, including energy, time, and money are spent as a result of obligatory post-manufacturing heat and/or mechanical treatment to ensure optimum mechanical properties. One intrinsic fault in these technologies, which contributes to the need for treatment processes after part fabrication, is the creation of residual stresses during these processes. Residual stresses remain in …

With Great Power Comes Great Responsibility: Navigating Through Year One Of The Principalship, Angela Marie Reyna

Open Access Theses & Dissertations

Given the intense pressures, expectations, and public scrutiny, school principals now undertake even greater roles and responsibilities than their predecessors (DuFour & Mattos, 2013; Kellough & Hill, 2014; Hale & Moorman, 2003; Fullan, 2003; Deal & Peterson, 2010; Koozes & Posner, 2012). New, or neophyte, principals are expected to step in and maintain or increase test scores while navigating intricacies of the new position and school. The socialization experience into a new work environment, which can be magnified for neophyte principals, is a large indicator of principal success (Shaver, 2007). Developing trustworthy relationships with the school community has direct impact …

Complementary Charged Molecular Imprints Of West Nile Virus Antibodies, Julio Rincon

Open Access Theses & Dissertations

There is a significant demand for robust and stable receptor molecules that can mimic biological molecules, such as antibodies. Relying only on natural recognition molecules have greatly limited the uses and capabilities of many aspects of health sciences due to product expense and stability. This is especially important in medically underserved areas where the lack of resources and faulty or limited cold-chain makes antibody based diagnostics very difficult to implement.

With molecular imprinting, it is possible to recognize diseases with the added advantage of product stability, long term use, fast preparation and ease of scalability, all while being cost effective. …

The Former Asarco Demolition Fallout, A Post Study On Lead Soil Concentrations And Environmental Agents Of Redistribution In El Paso, Texas, Stephanie A. Robinson

Open Access Theses & Dissertations

The former El Paso ASARCO Smelting and Refining Co. operated between 1877 and 1999, the pyrometallurgic activity was estimated to have discharged excess of a 1,000 tons of lead (Pb) into the atmosphere from 1969-71. It was estimated 96 tons of (Pb) were emitted on an annual basis from the standing ore and fluid beds. The Environmental Protection Agency (EPA) determined that lead (Pb) is the heavy metal of the highest concentration within the vicinity of the smelter. After the smelter production ceased, flash flooding common to the southwest, such as the 2006 historic flood, increased transportation of superficial contaminants …

Using Underground Radon To Detect Inactive Geological Faults, Germán Rodríguez Ortiz

Open Access Theses & Dissertations

This Thesis presents the results of an investigation of the concentration of radon in soil around a fault in the East Franklin Mountains in the El Paso area in West Texas. The connection between underground radon exhalations near active faults has been known for decades, but possible similar increases of underground radon levels around inactive faults have not been studied as thoroughly. Arguing that the dilatancy-diffusion model used to explain the phenomenon near active faults does not apply to the case of inactive faults, a hypoThesis is formulated under which increased levels of underground radon must be present near inactive …

Impact Of Reclaimed Asphalt Pavement And Recycled Asphalt Shingles On Laboratory And Field Performance Of Texas Asphalt Concrete Pavements, Berenice Salaices Gomez

Open Access Theses & Dissertations

The use of recycled materials in Asphalt Concrete (AC) mixes is highly promoted in the transportation industry. Recycled materials minimize the use of virgin materials, reduce the consumption of resources, and cut costs for new construction or rehabilitation projects. The incorporation of Reclaimed Asphalt Pavement (RAP) and Recycled Asphalt Shingles (RAS) in the AC mixture is promoted as long as equal or improved performance is achieved. The Texas Department of Transportation (TxDOT) is currently placing asphaltic concrete (AC) mixes that are lasting less than their expected performance life when recycled materials are used.

The objective of this Thesis is to …

Microelectromechanical Systems Inertial Measurement Unit As An Attitude And Heading Reference System, Francisco Javier Salcedo Ortega

Open Access Theses & Dissertations

Microelectromechanical systems inertial measurement units (MEMS IMU) are an accessible technology that can be used as an attitude and heading reference system (AHRS); they are low cost and functional enough to be used in many Inertial Navigation Systems (INS). However, the gyroscope component on the IMU tends to severely drift over time without the use of filtering or other navigation systems reference such as a Global Positioning System (GPS) device. This Thesis is focused on working with a variety of IMUs to describe the accuracy, precision, and error propagation. It also works as an introductory guide to the world of …

Modeling The Effects Of Manufacturing Geometric Imperfections In The Buckling Analysis Of Three-Dimensional Structures, Juan Carlos Salcido

Open Access Theses & Dissertations

Reticulated three-dimensional structures follow design practices based on the common assumption that joints are either rigid, or pinned. However, the actual non-linear behavior of the jointing system interaction is required to be incorporated into the analysis of the structure to accurately predict its buckling stability. Besides, currently, there is a concern on how manufacturing imperfections of these jointing systems affect the global behavior of three-dimensional structures. This Dissertation incorporates and captures the effect that manufacturing geometric imperfections in the fir-tree jointing system produce in the non-linear buckling behavior of three-dimensional structures.

To understand the effect that initial manufacturing imperfections of …

Towards A Unified Theory Of Engineering Education, Oscar Humberto Salcedo

Open Access Theses & Dissertations

STEM education is an interdisciplinary approach to learning where rigorous academic concepts are coupled with real-world lessons and activities as students apply science, technology, engineering, and mathematics in contexts that make connections between school, community, work, and the global enterprise enabling STEM literacy (Tsupros, Kohler and Hallinen, 2009). The purpose of the Dissertation is to develop a unified theory of engineering education based on philosophies of mathematics, science, technology & engineering, and engineering education. Using purposive sampling methods, the Thesis constructs "representative" philosophy statements from the STEM fields based on the criteria of Constructivism, Progressivism, and/or Pragmatism. These statements are …

Seismic Investigation Of The Kunlun Fault: Analysis Of The Indepth Iv 2-D Active-Source Seismic Dataset, William Seelig

Open Access Theses & Dissertations

The Tibetan Plateau has experienced significant crustal thickening and deformation since the continental subduction and collision of the Asian and Indian plates in the Eocene. Deformation of the northern Tibetan Plateau is largely accommodated by strike-slip faulting. The Kunlun Fault is a 1000-km long strike-slip fault near the northern boundary of the Plateau that has experienced five magnitude 7.0 or greater earthquakes in the past 100 years and represents a major rheological boundary. Active-source, 2-D seismic reflection/ refraction data, collected as part of project INDEPTH IV (International Deep Profiling of Tibet and the Himalaya, phase IV) in 2007, was used …

Investigating Mathematics Self-Efficacy Beliefs Of Elementary Pre-Service Teachers In A Reform-Based Mathematics Methods Course, Abdelghani Setra

Open Access Theses & Dissertations

For the last thirty years research has unfailingly shown that teacher efficacy has a positive impact on student outcomes, making teacher efficacy an critical element in quality mathematics instruction. The purpose of this study is to examine the impact of a math methods course on the mathematics teaching efficacy beliefs of elementary pre-service teachers. Seventy participants from four classes were students enrolled in ELED 4310 math methods course responded to the Mathematics Teaching Efficacy Beliefs Instrument (MTEBI) on

first and last week of class. Paired sample t-tests were used to analyze the quantitative data. mixed methods design was implemented to …

Time Degradation Of Perovskites, Nazia Sharmin

Open Access Theses & Dissertations

Perovskite organic-inorganic compounds are of interest for photovoltaic purposes, unfortunately, some of the organic-inorganic elements tend to evaporate rather rapidly rendering the films less effective for photoelectric use. In this study, we examine the evaporation of Perovskite organic-inorganic compounds produced by several manufacturing techniques. In particular we perform XRF and XPS inspections as a function of time and determine the fabrication method that best conserves iodine and lead.

Pyroelectric Ceramics As Temperature Sensors For Energy System Applications, Jorge Luis Silva

Open Access Theses & Dissertations

Temperature is continuously monitored in energy systems to ensure safe operation temperatures, increase efficiency and avoid high emissions. Most of energy systems operate at high temperature and harsh environments to achieve higher efficiencies, therefore temperature sensing devices that can operate under these conditions are highly desired. The interest has increased in temperature sensors capable to operate and in harsh environments and temperature sensors capable to transmit thermal information wirelessly. One of the solutions for developing harsh environment sensors is to use ceramic materials, especially functional ceramics such as pyroelectrics. Pyroelectric ceramics could be used to develop active sensors for both …

Optimization Of Neural Network Architecture For Classification Of Radar Jamming Fm Signals, Alberto Soto

Open Access Theses & Dissertations

Radar jamming signal classification is valuable when situational awareness of radar systems is sought out for timely deployment of electronic support measures. Our Thesis shows that artificial neural networks can be utilized for effective and efficient signal classification. The goal is to optimize an artificial Neural Network (NN) approach capable of distinguishing between two common radar waveforms, namely bandlimited white Gaussian jamming noise (BWGN) and the ubiquitous linearly frequency modulated (LFM) signal. This is made possible by creating a theoretical framework for NN architecture testing that leads to a high probability of detection (PD) and a low probability of false …

The Effects Of A Discrete Covariatonal Approach To Functions Through Computer Programming On Students' Understanding Of Rate Of Change, Michael Wayne Strange

Open Access Theses & Dissertations

Having a broad understanding of functions is paramount to student success in higher math classes, however most students fail to fully develop this concept during their high school years. While the concept of function is multifaceted and a full understanding requires a broad knowledge base, understanding rate of change can be considered a fundamental component of the concept. Unfortunately, even AP Calculus students have difficulty with rate of change (Teuscher & Reys, 2012). The problem may stem from the approach taken in most curricula that focus on the correspondence view of functions rather than the covariational perspective as advocated by …

Raman Microscopic Analysis Of Internal Stress In Boron-Doped Diamond Thin Films, Emma M.A. Sundin

Open Access Theses & Dissertations

The correlations between induced stress on undoped and boron-doped diamond (BDD) thin films, sample chemical composition, and fabrication substrate are investigated in this study via confocal Raman microspectroscopic analysis. Stability of BDD films is relevant to fast-scan cyclic voltammetry, as film delamination and dislocation of BDD-coated electrodes that can occur during neurosurgical electrode implantation can negatively impact the biosensing reliability of this technique. Electrodes were fabricated by coating cylindrical tungsten rods using a custom-built chemical vapor deposition reactor. The results of the analysis reveal a direct correlation between regions of pure diamond and enhanced material stress, as well as preferential …

Evaluation Of A Roller Method For Geochemical Leach Testing, Troy Allen Svede

Open Access Theses & Dissertations

Currently, multiple tests are being used when evaluating an MSE wall backfill material for pH, conductivity, chloride concentration, and sulfate concentration. There is no one test to measure all four characteristics when testing a soil. Texas Department of Transportation (TxDOT) uses four different tests to measure these characteristics. The goal of this research was to refine a simplified test procedure that was created by David Borrok et al., the Tex-620-M. The method that was developed to replace the current TxDOT test procedures Tex-620-J, Tex-128-E, and Tex-145-E test procedures is the Tex-620-M2. Leaching kinetics were analyzed for gravel and fines by …