Engineering Commons^™

Analysis Of Travel Behavior At International Border Crossings: Application Of Travel Surveys, Jennifer Areli Moreno Escamilla

Open Access Theses & Dissertations

Transportation planning provides an insight into the demand and traffic distribution of existingconditions of a region and helps identify future transportation needs. The results generated from forecasting models influence many decisions on the selection of transportation projects and funding allocations. Thus, forecasting models require up-to-date trip information to represent trip patterns and generate representative traffic demand analysis in a such complex areas as binational regions. The purpose of this study is to provide an analysis on travel survey methodology applied to collect trip information at international border crossings. Based on the results of the survey, an analysis on trip pattern …

Ultra Wide Band Gap Oxides For Advanced Optoelectronics And Supercapacitor Applications: A Case Study Of Intrinsic And Doped Germanium Dioxide, Paul Gaurav Nalam

Open Access Theses & Dissertations

Germanium dioxide (GeO2) is a metal oxide semiconductor with multiple polymorphs that has recently garnered a significant amount of scientific attention owing to its novel ultra-wide band gap and pseudo-capacitive properties, which can potentially transcend current power electronic, optoelectronic, and supercapacitor technologies. However, due to the difficulty in the synthesis of stable crystalline phases of individual polymorphs of GeO2 thin films, this material system demands complex and resource-intensive deposition techniques to synthesize. An attempt was made to develop cost-effective and scalable deposition techniques to stabilize specific crystalline phases of GeO2 thin films. These phases were further structurally fine-tuned to state …

Enhancing Damage Tolerance Of The Constituents Of Sandwich Composites, Zackery Nieto

Open Access Theses & Dissertations

Composite structures have become a lucrative material choice for researchers throughout various sectors such as green energy, arctic travel, and aerospace application due to their light weight, high-bending to stiffness ratio, and job tailorable applications through material selection. With the increasing demand for new and better composite technologies growing each year it is imperative to investigate new materials and analytical options to help the composite field as a whole grow. In this report various materials and statistical applications have been studied regarding the constituent materials in sandwich composites. For core materials an additive manufactured photoreactive resin has been characterized for …

Ultrasonic Non-Destructive Evaluation Of Additively Manufactured Polymer-Ceramic Composites, Christian Alexander Ruiz

Open Access Theses & Dissertations

Digital light processing (DLP) is an attractive additive manufacturing technique due to its ability to create ceramic parts with complex geometries. DLP uses ultraviolet light to polymerize a slurry comprised of ceramic powder and photosensitive resin in layers to create solid parts. Printing parameters such as light intensity and exposure time are critical when producing these parts. Improper parameters can lead to over or under-curing, adversely impacting print quality and strength. Samples were printed at varying layer exposure times and then tested using ultrasonics to determine the degree of conversion. Additionally, ultrasonics were used as a non-destructive technique to obtain …

Development Of A 3d Printed Conductive Biopolymer For Cardiac Tissue Engineering, Britanny Lizeth Stark

Open Access Theses & Dissertations

Cardiovascular disease (CVD) is the leading cause of death in the US, with approximately 859,000 deaths each year. The major contributor to CVD is Acute Myocardial Infarction (AMI), which causes the death of approximately 25% of the cardiomyocytes present in the left ventricle of the heart. After AMI, the adult human heart has a very limited regenerative capacity. Moreover, the electrical propagation of the myocardium is severely disrupted, making the heart more susceptible to failure and patient death. However, current pharmacological treatments do not address the loss of cardiomyocytes and the disruption of electrical propagation in the heart. Tissue engineering …

Characterization Of Fcc Al-Cu-Ni-Mn-Ag High Entropy Alloy, Gina Zavala Alvarado

Open Access Theses & Dissertations

The effect of Ag on the microstructure developed in Al-Cu-Ni-Mn alloy has been determined. The modified Al-Cu-Ni-Mn alloy by Ag addition shows the presence of three microconstituents consisting of phases rich in (1) Cu, (2) Ni, and (3) Ag. The foregoing alloys heated for 24 hours from 600 to 1000 °C show excellent oxidation resistance. Oxide formation and microstructural changes of the alloy have been characterized by elemental mapping and X-ray diffraction (XRD). Results show that the elements of Al and Mn preferentially oxidize while Cu and Ni provide oxidation resistance to the alloy. Hardness was taken on the alloy …

Enhancing Power System Flexibility Through Efficient Integration Of Facts And Electric Vehicles, Izaz Zunnurain

Open Access Theses & Dissertations

The global transition towards a cleaner and sustainable energy landscape has led to the integration of renewable energy sources and electric vehicles (EVs) into the modern power system, along with their complexities. Due to the high penetration of renewable energy sources and rapid growth of EVs, the power grid often experiences congestion, increasing the overall operating cost of the power system and directly jeopardizing the power stability and quality of the grid. A flexible and resilient power infrastructure that can accommodate the intermittency of renewable energy sources and the adoption of EVs is very much required to ensure the reliability …

Viability Of Magnetic Nanoparticles For Magnetic Hyperthermia Cancer Therapy, Marcos Adrian Garcia

Open Access Theses & Dissertations

Over the last few decades magnetic nanoparticles have gained an extraordinary amount of attention in the science community. Their versatile use in many different research areas such as medicine, engineering and technology and many other areas has made them a popular subject. In this thesis, the synthesis of different systems of magnetic nanoparticles will be explored along with the potential use of the MNP's as viable candidates for Magnetic Hyperthermia Cancer Therapy. With values of over 200 emu/g for Iron-Silver magnetic nanoparticles with particle sizes ranging from 30-70nm and their heating properties under an AC magnetic field. As well of …

Exploration Of Advanced Scan Strategy Capabilities On A Commercial Lpbf System Using Intervector Power Ramping, Antonio York

Open Access Theses & Dissertations

Lack of confidence in the quality of materials produced with metal AM has hinged on the unaddressed defects inherent to the process. Studies have worked to determine defect formation mechanisms and provide adjustments to key process controls. However, these advances have typically been developed in-house on research systems which offer increased and transparent control to the operator. A research gap exists in applying changes in approach of scan strategies to existing commercial systems, which can incentivize adoption while furthering development. The focus of this study is the implementation of inter-vector power ramping on a commercial laser powder bed fusion system …

Upcyclying Of Polyethylene Terephtalate By Addition Of Thermoplastic Elastomer, Diego Francisco Bermudez

Open Access Theses & Dissertations

Continual overconsumption of single-use plastics has generated challenges of solid waste management across the United States. Common plastic waste management solutions, such as landfill, have caused the migration of contaminants into the environment consequently affecting not only the health of wildlife, but also that of human beings. Alternative strategies for the handling of single-use plastic such as polyethylene terephthalate (PET), used in the food packaging industry, can ultimately help mitigate the noxious consequences of single-use plastics affecting entire ecosystems. This study demonstrates a potential avenue of materials upcycling by studying the effects of coupling PET with the thermoplastic elastomer styrene-ethylene-butylene-styrene …

Design And Customization Of 3d Printers For Advanced Materials Printing, Alan Omar Loera Martinez

Open Access Theses & Dissertations

This research is divided into two sections. The first section discusses modificationsperformed to two commercial printers. The first printer was modified from a thermoplastic polymer printer to a pneumatic printer by taking away its heating elements and print head. Circuits were directed to pneumatic dispensing system as well in order to automate the process. The second printer had mechanical modifications performed to be a multi-material gradient printer by controlling two stepper motors through an electronics board. Through code, a mixing ratio changed the motors' rotations to provide the desired gradient of two different materials. The second section of the present …

Design And Development Of Transition Metal-Based Electrocatalysts For Environmentally Friendly And Efficient Hydrogen Evolution Reactions (Her), Navid Attarzadeh

Open Access Theses & Dissertations

Hydrogen fuel is a clean energy source primarily because it emits no carbon dioxide (CO2). Sustainable energy alternatives have attracted the scientific community and policymakers as concerns over global warming and depletion of fossil fuels have increased significantly. Substituting H2 gas as a primary source for our daily energy consumption under the guideline of the hydrogen economy concept has not progressed as anticipated because of inadequate efficiency associated with the generation (electrolyzer) and utilization (fuel cell) devices. However, there are challenges associated with hydrogen that must be overcome for it to become a truly sustainable and widespread energy source. The …

Integration Of Biomedical Engineering And Computer Vision For Morphological Alteration Identification In Diabetic Cardiomyopathy: An Analysis And Evaluation Stra Tegy, Monica Delgado

Open Access Theses & Dissertations

Diabetic cardiomyopathy (DCM) is a type of heart disease that affects people with diabetes. It is characterized by changes in the structure and function of the heart, including thickening and stiffening of the heart muscle, impaired relaxation of the heart, and reduced pumping function. DCM is considered an ailment of the heart muscle and an increased risk factor in people with type 2 diabetes mellitus (T2DM). Although the exact mechanisms behind DCM are not fully understood, high blood glucose levels are known to contribute to the development and progression of the disease.While many options to manage and diagnose DCM have …

Studies On Atomic And Molecular Properties Using Locally Scaled And Perdew-Zunger Self-Interaction Corrected Density Functional Approximations, Philip Adeniyi Oyedele

Open Access Theses & Dissertations

This thesis examines some properties of atoms and molecules using one-electron self-interaction-correction (SIC) methods such as the Perdew-Zunger SIC (PZSIC) and the locally scaled SIC method of Zope and coworkers within the Fermi-Lowdin SIC formal- ism. The accuracy of electron density is examined by comparing moments of the den- sity, ⟨r^n⟩ = ∫ ρ(r)rndτ = ∫ ∞ 0 4πr2ρ(r)rndr (n = −2, −1, 0, 1, 2, 3) with the corresponding available values from the Coupled cluster (CC) singles, doubles, and perturbative triples (CCSD(T)) method. Three test sets are considered: boron through neon neutral atoms, two and four electron cations, and …

Impact Of Clay Contamination On Rutting Performance Of Asphalt Mixes, Sharmila Afsha

Open Access Theses & Dissertations

Sustainability of asphalt mixtures can be improved by using natural sands. They can enhance workability and lower the amounts required for asphalt binder and manufactured fine aggregate of mixes. However, one of the primary concerns with incorporating natural sands in a mixture is clay contamination. Harmful clays are chemically active particles that swell when exposed to moisture and reduce the bond between aggregate and asphalt binder. As a result, this study explores the effect of clay contamination on the rutting and moisture susceptibility of asphalt mixes. Twenty-one clay combinations of material passing the 0.075 mm (#200) sieve were selected utilizing …

Inkjet-Printed Electrochemical Sensors For Lead Detection, Annatoma Arif

Open Access Theses & Dissertations

This PhD dissertation research has developed a simple, miniaturized, sensitive, selective, reproducible, and disposable 3D (inkjet printed – additive manufacturing technology) gold (Au) plated electrochemical sensor (ECS) on shape memory polymer (SMP) for aqueous lead detection. This technology has shown promising performance in the application of electrochemical sensing (lead (II) detection) due to increased effective electrode surface area (7.25 mm^2 ± 0.15 mm^2) despite miniaturizing lateral surface area (4.19 mm^2). The design, fabrication processes, optimization including bismuth functionalization, evaluation, uncertainty analysis, and cost analysis of the novel SMP based inkjet printed Au plated sensor have been delineated in this manuscript …

Double Cantilever Beam Mode-I Testing Validation In Large-Scale Additive Manufacturing Carbon Composite, Luis Alfonso Camacho

Open Access Theses & Dissertations

Testing for mechanical properties for additive manufacturing has been based on already existing standards for traditional manufacturing methods. For composites in large scale additive manufacturing there is a research gap in bond strength and fracture toughness for a single layer interface. By using Double cantilever beam Mode I, this thesis manuscript validates testing parameters and protocols to describe the intricacies of ABS matrix 20 wt.% carbon filled composite, specifically on the layer-to-layer interface. Studies suggest that fracture toughness is sensitive to process parameters, like deflection speed and sharpened crack tip at the layer interface of BAAM 3D printed part and …

How Active Rainwater Harvesting May Help Reduce Nuisance Flooding: Flood Analysis And Social Barriers To Adoption, Isabel Lopez

Open Access Theses & Dissertations

As urbanization continues to expand, fewer pervious surfaces are available to help reduce stormwater runoff from rainfall. The impacts of urbanization are becoming evident through sunny day flooding - flooding that occurs in areas not designated by the Federal Emergency Management Agency (FEMA) as flood zones. Nevertheless, water accumulates in low-lying areas and compromises street intersections and other parts of neighborhoods. Some methods can help alleviate the impacts of unexpected heavy rains, such as passive and active rainwater harvesting. As a pilot study, in a selected area in the northeast of El Paso, the level of adoption (e.g., what percentage …

Metal Additive Microfabrication Of Semiconductor Packages With Inbuilt Thermal Management System, Bhushan Lohani

Open Access Theses & Dissertations

Moore’s law describes the development capabilities in electronics manufacturing. Although his estimation held for decades, at present, the doubling of components every two years seems to be approaching a halt. The assessment was based on the miniaturization of transistors to create space for more. Miniaturization led to higher component density, decreased cost, lowered power consumption, and compactness. However, it also came with high current density, increased Joule heating, and reduced critical charge. One of the limiting factors is the heat generated from such devices, which is heavily discussed in International Roadmap for Devices and Systems (IRDS) and International Technology Roadmap …

The Effects Of Process Parameters On The Cyclical Life Of Ti-6al-4v Manufactured Via Laser Powder Bed Fusion, Brandon Ramirez

Open Access Theses & Dissertations

Additive manufacturing via Laser Powder Bed Fusion (LPBF) has already proven revolutionary technology. Due to its favorable strength-to-weight ratio, ti-6Al-4V, a popular titanium alloy, has already been implemented in the aerospace industry for various components. However, the quality validation in additively manufactured parts has always been an issue of concern, specifically under cyclic loading. Ti-6Al-4V samples were printed using LPBF with various process parameters to investigate these conditions further. The build was stress-relieved; however, the samples underwent no other post-processes maintaining their as-built surface. The process parameters were separated into five categories, including various laser powers and printing speeds, allowing …

Geometrical And Surface Texture Characterization For Laser Powder Bed Fusion Process, Jesus Alfredo Rivas

Open Access Theses & Dissertations

Laser powder bed fusion (LPBF) is one of the most widely used additive manufacturing (AM) methods for metal parts. Geometrical tolerances required for industry applications are determined by geometrical measuring methods and process capability calculations. However, geometry characterization presents challenges for LPBF because measuring uncertainty values are not defined and the standardized measurement framework Geometric Tolerancing and Dimension (GD&T) is not fully adopted.

Measurement uncertainty is influenced by this process's high surface roughness (10 µm < Ra ⩽ 80 µm). As an example, when using multiple probing points or scanning pathways on a LPBF surface with the most accurate (+/- 0.004 mm) and traceable measurement method, the coordinate measuring machine (CMM), the results can vary by up to 0.050 mm to 0.070 mm. This measurement uncertainty leads to an imprecise benchmark reference for comparison with optical or X-ray computed tomography (XCT). These measurement variations also make it difficult to accurately characterize parts for automotive, aerospace, medical and other high-tech industries, such as a turbine blade geometry used in aircraft engines with a blade height tolerance of +/- 0.15 mm, which required a measurement uncertainty less than 30% of the tolerances. Mechanical properties such as tensile testing assessments useful in comparisons of materials, alloy development, quality control, and design under certain circumstances are also affected by this imprecise geometry characterization. Overestimating the diameter of the ASTM E8 sample by 0.100 mm can make up to a difference in stress results of 7%.

This research aimed to evaluate various measurement approaches (contact and non-contact) for surface texture and geometrical size dimension characterization and provide information regarding measurement uncertainty …

Rigid Pavement Analysis System (Rpas): An Enhanced Graphical User Interface, Samina Samrose

Open Access Theses & Dissertations

In recent decades there has been a significant interest among researchers in developing pavement analysis tools that will work with high efficiency and provide accurate results within a short timeframe. The University of Texas at El Paso (UTEP) has developed a finite element-based pavement analysis software named â??Rigid Pavement Analysis Systemâ?? (RPAS) capable of analyzing Jointed PCC pavements of any number of PCC and soil layers. The processing core of this software was developed in MATLAB with a pre- and post-processing user interface developed in C++. The MATLAB code is compiled into an executable and together with the C++ interface …

Biomass-Mediated Metastable Zinc(Ii) Oxide Nanoparticles And Its Nanocomposites For Sustainable Water Treatment, Kazi Afroza Sultana

Open Access Theses & Dissertations

Water is undeniably the most crucial resource that allows all living entities to thrive and survive. Due to a continuously growing population and the expansion of industrial sectors, water pollution has emerged as a global issue. Consequently, people face challenges in obtaining the required quantity and quality of water for their daily activities such as drinking, cooking, hygiene, and agriculture. Hence, there is a compelling need to develop an effective and environmentally friendly approach to eliminate harmful pollutants in water, promoting the establishment of a sustainable society with widespread access to clean and safe water resources. Although there are a …

Performance Evaluation Of A Coupled Photovoltaic-Thermal Solar Powered Desalination Pilot System, Martin Chavarin

Open Access Theses & Dissertations

A pilot scale coupled photovoltaic-thermal solar powered desalination system was evaluated at the Brackish Groundwater National Desalination Research Facility (BGNDRF). The pilot system consisted of a 3-kW photovoltaic-thermal (PVT) solar panel array and a 2.3 kW photovoltaic (PV) array coupled with a 4 gal/min single-stage 4 membrane reverse osmosis (RO) desalination system. A heat exchange system was in place to provide simultaneous cooling for the PVT system and heating to the RO system feed water. This system was evaluated with three objectives in mind. The first objective was to identify whether cooling of the PVT panels resulted in a significant …

A Novel Approach For Defect Detection Of Wind Turbine Blade Using Virtual Reality And Deep Learning, Md Fazle Rabbi

Open Access Theses & Dissertations

Wind turbines are subjected to continuous rotational stresses and unusual external forces such as storms, lightning, strikes by flying objects, etc., which may cause defects in turbine blades. Hence, it requires a periodical inspection to ensure proper functionality and avoid catastrophic failure. The task of inspection is challenging due to the remote location and inconvenient reachability by human inspection. Researchers used images with cropped defects from the wind turbine in the literature. They neglected possible background biases, which may hinder real-time and autonomous defect detection using aerial vehicles such as drones or others. To overcome such challenges, in this paper, …

Electrochemical Approaches To Life-Support Resources In Space Missions And Nuclear Technologies: Hydrogen Peroxide And Uranium Films, Armando Manuel Pena-Duarte

Open Access Theses & Dissertations

Space race has developed several technological advances that have achieved and continue to achieve the success of space missions in the aerospace timeline. Currently, the number of space technical and scientific innovations is still growing––demanding new materials and developments for extreme performing applications of fuel cells, batteries, supercapacitors, and systems of nuclear energy. Space missions require life-support solutions, auto-sustainable closed-loop living environments, cleaning and sanitizing solutions against pathogens, and safe nuclear-based resources of energy––with fissile materials with well-controlled dimensions within the core fuel elements. Likewise, to guarantee safety conditions, reduce costs, and facilitate operational logistics, space missions must reduce their …

The Genetic And Non-Genetic Factors For Impulsivity, Erick Benjamin Saldes

Open Access Theses & Dissertations

Inhibitory control is an executive function suppressing inappropriate actions or thoughts and inhibitory control dysfunction leads to impulsivity. Impulsivity is associated with wide-ranging brain disorders including attention deficit hyperactivity disorder, autism spectrum disorder, substance use disorder, and dementia. The genetic and non-genetic factors contributing to impulsivity are poorly understood. This dissertation aims to begin closing this knowledge gap by identifying the genetic and non-genetic factors for impulsivity and the underlying mechanism in the model organism Drosophila melanogaster. For this task, we developed a new Go/No-Go test, which measures the fly's ability to suppress movements in situations that can endanger its …

Using Machine Learning And Distributed Hydrologic Modeling To Predict Soil Texture, Surface Soil Moisture And Evapotranspiration In Jornada Experimental Range, Southwestern U.S., Jorge Andres Mayo

Open Access Theses & Dissertations

In water-limited ecosystems, detailed knowledge of the soil, vegetation, and atmosphere interactions is critical to understand the processes that control the partitioning of energy, water fluxes, and biogeochemical cycles within the critical zone. This Master's thesis is divided into two main contributing sections. The first, is on the use of machine learning to reconstruct missing soil type information, and the second, on the calibration and validation of a physically-based distributed hydrological model to estimate soil moisture and evapotranspiration within the Jornada Experimental Range of the U.S. in southern New Mexico. For the first contribution, three explainable, shallow machine-learning techniques are …

Characterization Of Novel Self-Healing Polymer Blends For Additive Manufacturing, Truman James Word

Open Access Theses & Dissertations

This dissertation begins with an overview of novel polymer systems which have been developed by the Polymer Extrusion Lab at the University of Texas at El Paso. Many composite polymer systems have been created using many different polymers as well as ceramics and metals primarily in the form of powders added to the bulk polymer. The bulk of this work entails a study that was conducted to develop and characterize the mechanical, shape memory and self-healing properties of three polymer blends: polylactic acid (PLA) combined with maleated styrene-ethylene-butylene-styrene (SEBS-g-MA), acrylonitrile butadiene styrene (ABS) combined with maleated styrene-ethylene-butylene-styrene (SEBS-g-MA), and polylactic …

Catalytic Water Photolysis For Generating Renewable Hydrogen Fuel, Dr. Niveditha Nanda

Open Access Theses & Dissertations

Modern advances have enabled rapid industrialization and urbanization. However, the consequences of global modernization have included significant pollution to the air and water resources. Consequently, many changes to energy use must come to address and mitigate damages to our future. Solar energy derived hydrogen gas is a clean, renewable fuel that does not produce carbon dioxide or other pollutants. My research investigates the use of heterogeneous photocatalysis, by focusing on solar photochemical energy conversion, which is the making of hydrogen from water using sunlight. The production of clean, renewable hydrogen fuel will enable the utilization of low-cost, pollution-free energy resources …