Engineering Commons^™

Enhancement Of Fabrication Procedures By Modularization, Andres Sagredo

Open Access Theses & Dissertations

Fabrication of semiconductor technology grows in importance every year, from metal-oxide-semiconductor (MOS) technology to fabricating integrated circuits (ICs) used in everyday life. These ICs are implemented into computers, phones, and vehicles for complex functions and safety features. Another semiconductor technology is microelectromechanical systems (MEMS), located in actuators and sensors on multiple systems. In academia, it is inherently essential for students to learn the theory of such devices and have exposure to the fabrication process of the technology in question. The importance of theory and practice in fabrication is skyrocketing due to the global chip shortage, making workforce development vital for …

3d Printing Of Ceramics And Polymers For Engineering Applications, Jesus Javier Mata

Open Access Theses & Dissertations

The Additive Manufacturing industry, in the last years [1] has shown a great push with the development and inclusion of new technologies that have enable the engineering world to achieve great advances. As a consequence of this surge of new technology deriving from the basic principle that conforms additive manufacturing, according to the ASTM a total of seven categories have been defined. The inclusion of these new technologies and the ongoing advances in material implementation has provided the industry with a degree of freedom never seen before, leading to the creation of new solutions to existing problems that seemed impossible …

Equity Driven Data Analysis For Public Transportation Planning, Gerardo Ivan Valenzuela Mendoza

Open Access Theses & Dissertations

Existing public transportation planning methods use a trip-based approach rather than a user-based approach; a user-based approach is sensitive to a broader range of planning strategies and policies, especially those that affect or take into consideration how users spend their time and resources. Even though transportation planning agencies such as Metropolitan Planning Organizations (MPOs) are required to strive for environmental and social justice, there is still a gap that needs to be filled. Urban population growth and urbanization with its impact on public planning require continuous research to address the constantly evolving challenges when it comes to transportation. As cities …

The Mobility And Cognitive Mechanisms Involved In Altering Gait Speed In Children With Autism Spectrum Disorder, Alyssa Olivas

Open Access Theses & Dissertations

Autism is a socio-behavioral disorder, and diagnoses are conducted through behavioral screening instruments. Recent research suggests motor deficits may be a core symptom of the disorder, as children with autism present with deficits in motor development, locomotor skills, and postural instability. In addition, children with autism often have affected, executive function, attention, and perception cognitive domains. Different gait speeds have been used to examine gait adaptations in other clinical populations. Additionally, individuals with decreased cognitive abilities have demonstrated difficulties in modulating their walking speed. There is limited research on mechanisms children with autism use to alter their gait speed, or …

Application Of The Continuum Damage Mechanics Wilshire-Cano-Stewart (Wcs) Model, Jaime Aaron Cano

Open Access Theses & Dissertations

In this study, the applications of the continuum damage mechanics-based Wilshire-Cano-Stewart (WCS) model are explored to predict rupture time, minimum-creep-strain-rate (MCSR), damage, damage evolution, and creep deformation. Increase knowledge in manufacturing methods has pushed the limit of material science and the development of new materials. Conventional testing is required to qualify materials against creep which according to the ASME B&PV III code, 10,000+ hours of experiments are necessary for each heat before materials are put into service. This process is costly and not feasible for new materials. As an alternative, models have been employed to predict creep behaviors and reduce …

Improving Efficiency At El Paso Water Canal Plant, Angel Bustamante

Open Access Theses & Dissertations

AbstractThis project focused on the savings associated with filter backwash and rewash water at the Canal plant. Canal plant is a conventional surface water plant owned and operated by El Paso Water. Approximately 330,000 gallons of backwash water and 84,500 gallons of rewash water are lost daily during normal operational conditions. The combined 414,500 gallons of water are equivalent to 1.27 acre feet per day. During a full eight-month surface water season, this is 305 acre feet. With the goal of optimizing the plant, residuals waste streams can be recycled to the head of the treatment plant. However, there is …

A Central Compact Hybrid-Variable Method With Spectral-Like Resolution, Md Mahmudul Hasan

Open Access Theses & Dissertations

Numerical methods for hyperbolic conservation laws have been a driving force for theresearch in scientific computing and simulation science in the past decades, as many physical, biological, and engineering systems are governed by these equations, such as fluid mechanics, tumor growth, and virtual wind tunnel simulations. Despite the existence of many schemes in the literature, people have never stopped searching for more accurate and efficient methods for these problems. Indeed, the increasing complexity of systems in emerging applications demands better resolution of sub-grid scale phenomenon whereas classical methods usually fail to deliver high-fidelity simulation results of such systems within realistic …

Rational Design Of Composite Nanomaterials For Water Treatment Applications, Mariana Marcos-Hernandez

Open Access Theses & Dissertations

Water quantity and quality have been affected in communities all around the world due to population growth, pollution, changes in land use, and climate change. In order to cope with existing and anticipated water demands and shortages, the use of treated or reclaimed water is an ongoing alternative that has helped communities all over the world address this problem. The adaptation of nanotechnology to traditional water and wastewater treatment processes offers new opportunities in technological developments. Unique size-dependent properties such as: high surface to mass ratio, high reactivity, high sorption capacities, fast dissolution, superparamagnetism, among others, provide high-tech efficient materials …

Phonon Thermodynamics Of Bcc Zirconium With Machine Learning, Vanessa Judith Meraz

Open Access Theses & Dissertations

First principles-based simulations have allowed us to explore emerging phenomena in a variety of systems. Its steadfast practicality has led to an increase in molecular and materials design ranging from drug discovery to planetary formation. However ubiquitous in its field, one of its biggest drawbacks is its computational cost, notably so in molecular dynamics simulations. To counter this setback, there have been many leading efforts in machine learning methods, whether it be in algorithms or network architectures. Our contribution uses an active learning algorithm paired with a tensor field network, e3nn. By steadily feeding new data points to our model, …

Material Synthesis And Machine Learning For Additive Manufacturing, Jaime Eduardo Regis

Open Access Theses & Dissertations

The goal of this research was to address three key challenges in additive manufacturing (AM), the need for feedstock material, minimal end-use fabrication from lack of functionality in commercially available materials, and the need for qualification and property prediction in printed structures. The near ultraviolet-light assisted green reduction of graphene oxide through L-ascorbic acid was studied with to address the issue of low part strength in additively manufactured parts by providing a functional filler that can strengthen the polymer matrix. The synthesis of self-healing epoxy vitrimers was done to adapt high strength materials with recyclable properties for compatibility with AM …

Development Of An Automated Electronic Prototyping System, Cesar Yahir Sanchez Zambrano

Open Access Theses & Dissertations

Prototyping systems with interconnected components can be a time and resource expensive process. The process consists of three main phases (design, build and analysis) with each having their own associated cost. For the case of electronic circuits, the building phase is the costliest phase among the three, being prone to human errors which causes the circuit to fail. All three phases of the prototyping process are important. However, often a disproportionate amount of time is spent on the build phase due to the difficulty of making and troubleshooting circuits by hand. In this thesis we will discuss a system that …

Suitability Of Low-Cost Additive Manufacturing For Polymer Electrolyte Fuel Cells, David Alexander

Open Access Theses & Dissertations

The purpose of this dissertation is to study the feasibility of low-cost additive manufacturing to fabricate polymer electrolyte fuel cell bipolar plate materials. Traditional manufacturing techniques include molding, milling, hollow embossing, hydro-forming, rolling, and electromagnetic forming. These processes are employed when a design has been selected due to higher costs at low volumes. The combination of high initial costs and bipolar plates being the most expensive component of the polymer electrolyte fuel cell creates incentive to mitigate this obstacle. The feasibility of low-cost additive manufactured bipolar plates will be proven by fabrication, post-processing, and characterization of printed test specimen. The …

All-In-One Multi3d System: Exploring Potential Of 5-Axis Material Extrusion Additive Manufacturing, Angel Vega

Open Access Theses & Dissertations

Additive Manufacturing (AM) has experienced consistent growth since its inception across its seven process categories, especially Material Extrusion (MEX) with systems that can be seen in commercial and industrial settings. As MEX evolves, innovation can be traced in the growing variety of available process materials and new system capabilities leading to greater interest in the technology across various industries including automotive, aerospace and even nuclear weapons. This has created an increasing demand for end-use parts from MEX systems leading to more complex machines with additional Degrees of Freedom (DoF), specialized workflows, and expanded post processing that address the drawbacks of …

Femtosecond Laser Machining Of Drilled Holes In Silicon Nitride, Stephani Nevarez

Open Access Theses & Dissertations

In this study, the laser drilling parameters of a Nd:YAG ultrashort pulsed laser are evaluated to produce zero taper through holes on silicon nitride ceramics. Manufacturing of ceramics is expensive and difficult because of the mechanical and thermal properties of ceramics, limiting applications. Additionally, the high level hardness of the ceramic can affect the ceramic and the manufacturing tool. There is a need to explore non-contact machining such as laser machining to expand the uses of ceramics in industry applications.In order to accomplish this goal, understanding of the physical mechanisms that occurs while laser ablation is needed. Furthermore, the minimum …

Practical Applications Of Pressure-Fed Lox/Ch4 Rocket Engines, James Susen Parks

Open Access Theses & Dissertations

The University of Texas at El Paso Aerospace Center is working on a family of LOX/CH4 pressure-fed rocket engines. The applications of a pressure-fed rocket engine include orbital launch vehicles and lunar ascent and descent vehicles. This dissertation focuses on the application of the CROME LOX/CH4 engines under development at UTEP. The dissertation contains three chapters on orbital launch vehicles and a fourth chapter on lunar descent/ascent vehicles. The first two chapters look at pressure-fed LOX/CH4 orbital launch vehicle design compared to an electric pump fed and a gas generator vehicle. The third chapter looks at the sensitivities in the …

Ultrahigh Strength-High Ductility Combination Low Density Austenitic Steel: Effect Of Aging Temperature And Strain Rate, Jaehyun Kim

Open Access Theses & Dissertations

The objective of the study was to optimize the post-thermal treatment of hot rolled Fe-0.92C-26.3Mn-8.79Al-0.05Nb steel. In this regard, the hardness of the experimental steel was studied as a function of aging time and/or strain rate. The study provided an understanding of aging heat treatment for the experimental steel, which was processed by vacuum induction melting, followed by thermo-mechanical rolling involving multiple passes. The rolled steel was subsequently annealed at 900 °C for 4 h followed by water quenching. X-ray diffraction in scanning mode of 2¸=20-100o indicated the presence of austenite structure. In order to study the influence of aging …

Investigation Of Refractory High Entropy Alloys For Extreme Environment Applications, Rebecca Alexandra Romero

Open Access Theses & Dissertations

High entropy alloys (HEAs) have emerged as an exciting class of materials with the potential for a wide range of structural, high-temperature applications. HEAs may be defined on a compositional basis as five or more principal elements in equimolar ratios. This definition led to the term “high entropy” due to the high configurational entropy which is obtained with principal elements in these amounts. The combination of elements has contributed to materials that may favor solid-solution phases over intermetallic phases and have the potential to possess highly desired material properties including high yield and creep strength. The inclusion of refractory metals …

Performance Evaluation Of A Label Manufacturer Using Simulation Modeling, Joshua Holguin

Open Access Theses & Dissertations

Currently, the Supply Chain has been affected by freight prices, material scarcity, demand forecasting, port congestion, and digital transformation which are causing high lead times and delaying deliveries in all industries, but specifically in the labeling/printing industry. The industry is currently affected by the lack of new research improvements, optimization methodologies, supply chain disruptions, and technologies implementations within the label industry. Labeling /Printing industry has been out in business for more than 50 years, where labeling technologies such as Flexographic, Digital, and Die Cutting have advance in performance, effectiveness, complexity, and dependability over the last years. The implementation of a …

Evolution Of The Magnetic Properties On Van Der Waals Layered Magnets Via Pressure And Proton Irradiation, Rubyann Olmos

Open Access Theses & Dissertations

Probing the magnetism in quasi two-dimensional materials has the potential in driving their properties towards future use in spin electronic based devices. Studying such layered magnets will enable the scientific community to uncover tunable exotic phases such as superconductivity, quantum paramagnetism, etc. This work examines the influence of two types of external perturbations, namely, the pressure and proton irradiation, on the magnetic properties of several compounds in the van der Waals crystal family.

Pressure has been found to induce structural and magnetic phase transitions in many of these materials. Using hydrostatic pressure as a disorderless approach to manipulate the interlayer …

Rational Design Of Multifunctional Nanocatalysts For Environmental Remediation And Energy Conversion Technologies, Md Ariful Ahsan

Open Access Theses & Dissertations

The discovery of efficient and sustainable carbon-based nanotechnologies to solve both the scarcity of drinking water and global energy crisis has become a paramount task in the last decades. Owed to the fast population growth and industrialization of the modern society, access to potable water and clean energy technologies is becoming very hard around the globe. Water pollutants have become a serious threat to the environment and ecology because of their toxic nature. Parallelly, the current hydrocarbon-based fuel industries are generating high levels of contamination across the planet, making imperative the development of cleaner energy technologies. In this regard, the …

Addressing Security And Privacy Issues By Analyzing Vulnerabilities In Iot Applications, Francsico Javier Candelario Burgoa

Open Access Theses & Dissertations

The Internet of Things (IoT) environment has been expanding rapidly for the past few years into several areas of our lives, from factories, to stores and even into our own homes. All these new devices in our homes make our day-to-day lives easier and more comfortable with less effort on our part, converting our simple houses into smart homes. This increase in inter-connectivity brings multiple benefits including the improvement in energy efficiency in our homes, however it also brings with it some potential dangers since more points of connection mean more potential vulnerabilities in our grid. These vulnerabilities bring security …

The Network Link Outlier Factor (Nlof) For Localizing Network Faults, Christopher Mendoza

Open Access Theses & Dissertations

This work presents the Network Link Outlier Factor (NLOF), a data analytics pipeline for network fault detection and localization solution that consists of four stages. In the first stage, flow record throughput values are clustered in two sub-stages: using Density-Based Spatial Clustering of Applications with Noise (DBSCAN) and then a novel domain-specific ThroughPut Cluster (TPCluster) technique. In the second stage, Flow Outlier Factor (FOF) scores are computed for each flow. In the third stage, flows are traced onto the network. Finally, in the fourth stage, each link is given a Network Link Outlier Factor (NLOF) score which is the ratio …

Goes-16 Level 2 Land Surface Temperature Product-Filling For Cloud Masked Data, Guadalupe Ortega

Open Access Theses & Dissertations

The GOES-16 satellite ground segment team develops different levels of environmental products and makes them readily available to the public. The level 2 Land Surface Temperature (LST) product aims to provide a remote measurement of the Earth’s surface temperature every hour. LST is of fundamental importance to many aspects of the geosciences, for example, to study the Urban Heat Islands (UHI) effect. The product however, does not provide values for pixels where the satellite imager’s view is obstructed by clouds, as determined by a cloud mask intermediate product. The objective of this thesis is to estimate LST in the cloud …

Predicting Zero Bin In The Semiconductor Manufacturing Industry: Machine Learning Algorithms, Yazmin Montoya

Open Access Theses & Dissertations

The semiconductor industry has faced supply chain manufacturing shortages that ultimately led to a worldwide chip shortage during the COVID-19 pandemic. These chip manufacturers use sophisticated and advanced manufacturing machinery in their fabs to manufacture chips. As experienced during the pandemic, manufacturing unavailability is often due to the lack of critical manufacturing-related spare parts. This thesis evaluates the effectiveness of machine learning algorithms to identify significant factors contributing to manufacturing part outages (i.e., zero-bin) to keep manufacturing equipment running at total capacity within the organization. We propose clustering methods to segment the data and use logistic regression, logistic lasso regression, …

Drying Of Digested Biosolids For Weight Reduction Prior To Disposal, Juan Manuel Canales

Open Access Theses & Dissertations

Disposal of belt filter pressed digested sludge (known as biosolids) to landfills cost El Paso Water about $1.1 million in the past year. With an increasing population, the amount of influent wastewater to El Paso treatment plants will also increase, resulting in increased biosolids generation and biosolids disposal costs. A method for reducing biosolids transportation cost is biosolids drying.The cost that El Paso Water pays for transporting biosolids to a dedicated landfill facility is based on the weight of the biosolids that are carried. Biosolids collected from the belt filter presses is about fifteen percent solids by weight, with water …

Thermodynamic Modeling Of Aqueous Fe-Cu-As-Sb-Bi-H2so4 Solutions And Its Application For Redox Potential Determination In Copper Electrorefining From 25°C To 70°C, Yongteng Dong

Open Access Theses & Dissertations

Impurity elements in copper electrorefining (ER) electrolyte have been becoming a crucial issue on purity of copper cathode. The objective of this doctoral research is to develop a speciation model to understand impurity behavior in aqueous ER solutions.

A thermodynamic model of Fe(II)-Fe(III)-Cu(II)-H2SO4-H2O system is developed and shown to reliably simulate the species distribution in industrial copper electrorefining electrolyte from 25°C to 70°C. The previously developed model of Fe(II)-Fe(III)-H2SO4-H2O system under leaching conditions was first evaluated. It has proved that its applicability can be extended to much higher acid concentration (185 g/L) and high amount of copper (40-50 g/L). Cu(II) …

Supercritical Co2 Recompression Closed Brayton Cycle Analysis, Andres Eduardo Gutierrez Hernandez

Open Access Theses & Dissertations

On this research, the results of an analysis made of a Supercritical Carbon Dioxide (sCO2) Recuperated Closed Brayton Cycle (RCBC) done by performing theorical calculations and comparing it to the results obtained with the use of the software ASPEN Plus will be presented. To demonstrate and determine that this software is a useful tool for modeling the proposed type of cycle, a preliminary comparison was made to verify with previous studies found in literature. A comparison and analysis between the possible working fluids and thermal energy sources was also performed to emphasize the decision of using CO2 as the cycle …

Synthesis And Characterization Of Tin (Sn) Incorporated Ga2o3, Guillermo Nicolas Gutierrez

Open Access Theses & Dissertations

In this work, we report on the synthesis, characterization of tin (Sn) incorporated gallium oxide Ga2O3 compounds, also included in this work is the effect of tin concentration related to the optical and electrochemical properties. The Sn incorporation into Ga2O3 creates a significant reduction in the bandgap and causes a nonlinear optical activity as the concentration varies. Substantial investigation performed to the structure, phase, and morphology of the mixed compounds governed by the stoichiometry equation Ga2−2xSnxO3-ɗ indicates that the Sn incorporation from 0.00 ≤ x ≤ 0.30 has a significant effect on these properties. To synthesize the Ga-Sn-O compounds a …

Rarified Water Vapor Deposition From Icy Lunar Regolith On An Engineered Cold Plate, Nathaniel Ian Jurado

Open Access Theses & Dissertations

This work presents the fundamental ice collection experiments conducted under rarefied flow regime to develop a high-capacity cryogenic heat pipe for ice recollection on the Moon’s surface. Preliminary ice collection experiments are conducted under cryogenic vacuum environment of 1.5 × 10-2 Torr and -60 °C. The characterization of water vapor sublimation rates from icy lunar regolith (JSC-1A) at various heating powers is established by utilizing a cryogenic thermal vacuum chamber (T-VAC). A custom-built engineered cold plate is designed, manufactured and tested at various degrees of subcooling and vapor sublimation rates. A thin film heater is embedded within the cold plate …

Evaluation Of Varying Graphene Oxides Through Their Physicochemical Characterizations On Erythrocytes, Hs27 Cells, Escherichia Coli And Staphylococcus Aureus Bacteria Cell Lines, To Assess Graphene Oxides Cytotoxicity., Miriam Montana

Open Access Theses & Dissertations

Research on the toxicity of Graphene Oxides (GO) has captivated interest in the field of material science, environmental sciences, and medicine for their avail significance in biomedical engineer applications either as integrates, enhancements, or in the making of medical devices. Moreover, there is still a lack of understanding as to what characteristics on GOs causes them to be cytotoxic at a cellular level. In our study we synthesized four different GOs by varying in both the method used for oxidation (Modified Hummer’s method & Improved Marcano-Tour’s method), and the precursor parent graphite, for a standardization approach to aid in the …