Engineering Commons^™

Using Ultrasonication For The Improvement Of Grade And Recovery In Molybdenum Sulfide Flotation, Wayne Alexander Campbell

Open Access Theses & Dissertations

Experimentation was performed on molybdenite slurry by using ultrasonication to elucidate the effects of ultrasonic-induced bubble cavitation on the grade, recovery, and gangue reduction during small-scale flotation tests and was followed by a topographical analysis of quartz particles using SEM. Ultrasonic waves at 20-80 kHz that propagate through a liquid medium cause microbubbles to form, grow, and implode. The cavitation bubble's implosion causes brief extreme local conditions where temperatures can reach 5,000 K and pressures of 1,000 bar. The resulting microjets create mechanical and chemical changes to the system and were directed at improving flotation dynamics in these experiments. Through …

Natural Resources Management Framework For Agricultural Irrigation Systems Optimization, Juan Valentin Fernandez

Open Access Theses & Dissertations

Water scarcity has increased substantially in the last decades in many parts of the world, and it is expected to worsen due to the significant increase in global water withdrawals, intensive population growth, and climate change. Water is easily one of the most essential and invaluable global resources due to its many uses, such as drinking, industrial processes, and irrigation. The agriculture sector is one of the most significant water users globally, accounting for nearly 70% of global freshwater withdrawals. Cities and industries compete with the agriculture sector for water sources, producing alarming levels of stress and pollution in the …

Evaluation And Implementation Of Lean Engineering Principles For Improving A University Rocket Team, Alan Garcia

Open Access Theses & Dissertations

In the present day, lean is a tool applied to manufacturing industries trying to reduce wasteand non-value-added work to every process during the supply chain. While implementing lean thinking in the industry has been highly effective, it is less common for academic purposes. However, it can also improve performance if the concept is correctly applied. The purpose of this thesis is to show and analyze the application of Lean Engineering thinking and its six principles to the Sun City Summit Rocket Team from the University of Texas at El Paso which competed in the Intercollegiate Rocket Engineering Competition (IREC) Spaceport …

Pressure-Induced Phase Transition And Electronic Structure Changes In Equiatomic Fev, Homero Reyes Pulido

Open Access Theses & Dissertations

Classical molecular dynamics methods can accurately describe a broad set of many-atomssystems. Although more economical, the results given by this framework lack the precision capable of density functional theory (DFT). Therefore, the structural stability of the B2 phase of a body-centered-cubic iron-vanadium (FeV) alloy using DFT on the electronic structure level is analyzed to verify and further explain classical results obtained by our group in this same alloy. Using Quantum Espresso and Phonopy for the computational simulations, the plotted band structure, electronic density of states (eDOS), phonon dispersions, charge density, and Fermi surfaces for various compressed unit cells are presented. …

Development Of Balanced Mix Design Quality Control Specifications Based On The Acceptance Limits Of Hma Performance Tests, Lucas Tameirao Abrantes

Open Access Theses & Dissertations

With the augmented use of recycled materials, recycling agents, modified binders, andwarm mix asphalt additives, several highway agencies including the Texas Department of Transportation (TxDOT), have considered methods to improve the durability and long-term performance of asphalt concrete (AC) mixes. The need for performance tests that could consistently evaluate the rutting and cracking potentials of AC mixes became crucial as the popularity of the Balanced Mix Design (BMD) concept has increased over the years. A concern now is related to the practicality of these tests for routine use in the process of quality control and quality assurance during the field …

Miner-Town: Self-Driving Robotics Testbed For Vehicle-To-Grid Simulation, Carlos Adolfo Cortes Pliego

Open Access Theses & Dissertations

Autonomous vehicles and Vehicle-to-Grid (V2G) technology bring promising implications in boosting energy efficiency, helping the environment, improving our productivity, and have the potential to stabilize the grid during peak times and reduce car accidents. However, implementing and testing these complex novel technologies in the real world comes with high risks and investment. For these reasons, there is the need to research, test, and validate these theories in a compact and controlled environment at minimal cost. This thesis presents a modular autonomous vehicle testbed for the exploration of Vehicle-to-Grid and charging activities in pedestrian filled environments such as a University campus. …

Multi-Sensor Signatures From Ultrasonic Wire Embedding Used In Hybrid Additive Manufacturing, Patrick Steven Gutierrez

Open Access Theses & Dissertations

Additive Manufacturing (AM) has matured such that its products are used in applications ranging from prototypes to end-use parts; however, to expand the adoption of AM, the inclusion of multiple manufacturing technologies has become a focus area especially when the result is a 3D printed part with an embedded electrical system. The W.M. Keck Center for 3D Innovation has developed the Foundry Multi3D system consisting of two material extrusion AM machines, a robotic arm, and a CNC machine equipped with a laser soldering tool, solder micro-dispensing tool and an ultrasonic wire embedding (USWE) tool. The focus of this paper is …

Design Of A Hemi-Anechoic Chamber For Acoustic Testing Of Hearing Devices And Development Of Custom-Designed 3d Printed Pinnae For Accurate Representation Of The Anatomical Frequency Response, Hector Hugo Estrada Medinilla

Open Access Theses & Dissertations

Sound localization is the capacity to identify the general location from which a sound is originating. The primary anatomical feature responsible for the ability to localize sound is the external portion of the ear, also known as the auricle or pinna. This faculty is significantly hindered when the ear is obstructed, as is the case with hearing protection devices (HPD), which act as a barrier between sound waves and the ear canal. In the case of electronic HPDs, certain frequencies are entirely filtered out by a digital sound processor (DSP) while the remaining frequencies are delivered directly into the ear …

Thin Film Evaporation Through Engineered Copper Micropillar Arrays, Alejandro Amador

Open Access Theses & Dissertations

This work explored and characterized the evaporator section of a fully engineered heat pipe, a proposed semi-passive cooling solution for the thermal management at high heat fluxes, with the use of thin film evaporation. High heat loads present a problem in electronics, circuitry, space, and defense applications which are the main target areas for this cooling solution. Conventionally manufactured flat samples made of copper micropillar arrays were tested to determine their heat removal capabilities for high heat flux applications. The samples were manufactured with 400 μm micropillar hydraulic diameter, various micropillar spacings ranging from 500-1100 μm, with 500 μm and …

Fetal Electrocardiogram Detection And Analysis From Maternal Abdominal Ecg For Diagnosis Of Fetal Heart Rhythm Abnormalities, Claudia L. Angel

Open Access Theses & Dissertations

Fetal cardiac arrhythmias are present in about 1–3% of pregnancies and account for about 10–20% of the referrals to fetal cardiology around the world. Most fetal arrhythmias are benign; however, some can cause fetal hydrops, preterm delivery, and higher perinatal morbidity and mortality. The evolution and treatment of fetal arrhythmia depend on a timely and complete diagnosis. However, conventional methods used in clinical practice for fetal arrhythmia diagnosis are limited since they do not reflect the primary electrophysiological conduction processes in the myocardium. Fetal electrocardiography (fECG) has the potential to better support fetal arrhythmia diagnosis through the continuous analysis of …

Oxygen Compatibility For Aerospace Materials, Jazmin Abril Arellano

Open Access Theses & Dissertations

The use of oxygen for aerospace applications is bonded to the history of American rocketry. The first liquid powered rocket engine used gaseous oxygen to pressurize both gasoline as fuel and liquid oxygen as oxidizer. Research and development about oxygen compatibility with aerospace materials has been continuously performed. However, no universal test has been developed to determine the oxygen compatibility of all materials yet. A review about oxygen properties, ignition mechanisms and their unique characteristic elements in addition to metals and nonmetals commonly used in oxygen systems and materials prohibited in oxygen applications can be found in this document. The …

Land Use/ Land Cover Change Patterns And Trends In Two Dryland Regions, Omar Sulaiman Belhaj

Open Access Theses & Dissertations

Development and climate change affect the environment in numerous ways and to varyingdegrees. This effect appears prominent and more influential in arid regions. Therefore, land use/ land cover in these regions experience profound changes such as plant cover decrease and extinction of some plant species. Also, land use/ land cover in these regions has critical impacts on the environment and its components, such as shrublands shrinking and losing the habitat of animal species. The degree of changes and effects reaches severe levels that become urgent to figure out the impacts and find solutions to stop or mitigate the negative consequences. …

A High Performance Software Intensive Testbed For Rapid Prototyping And Controlled Testing Of Lte And Wi-Fi Radio Frequency Signals, Mirza Mohammad Maqbule Elahi

Open Access Theses & Dissertations

Long Term Evolution or LTE has gained interest for new applications that can benefit society including mobile broadband services like 802.11 or Wi-Fi. Both LTE and Wi-Fi uses similar modulation technique Orthogonal Frequency Division Multiplexing or OFDM. 6GHz sub carrier bands are crowded with LTE users. As wireless communications technology continues to develop, LTE technology in unlicensed bands (LTE-U) is a viable solution to the lack of spectrum resources. The competition between LTE-U and Wi-Fi will seriously impair their communication quality, so the friendly coexistence of both become an important research topic. This paper discusses the use of a software-defined …

Characterization Of 3d Stereolithography (Sla) Printed Polymer For Autonomous-Flow Microfluidic Devices, Michelle Gamboa

Open Access Theses & Dissertations

3D Stereolithography (SLA) printing is a high-throughput, precise and reproducible manufacturing platform which makes it a desirable technique to develop microfluidic devices for bioanalytical applications. However, limited information exists regarding the physical, chemical, and biological properties of the polymer resins used in 3D SLA printing. This project demonstrates the characterization of a commercially available 3D SLA printed resin polymer used to develop an autonomous-flow (self-driven) microfluidic device. In this investigation, time-dependent materials characterization was done on the Formlabs clear V4 resin to observe changes in mechanical and surface properties. The clear, printed polymer was analyzed with attenuated total reflectance (ATR), …

Algorithms For Exploration Of Advanced Electromagnetic Concepts, Asad Ullah Hil Gulib

Open Access Theses & Dissertations

3D printing is revolutionizing the manufacturing industry and is now being considered in the electronics industry. The creation of the worldâ??s first 3D volumetric circuit has made a way to make circuits smaller, lighter, into unconventional form factors and exploit physics like anisotropy more effectively than planar geometries can. While this is exciting, many problems must be solved to make 3D volumetric circuits more efficient. One of these problems is electromagnetic interference and mutual coupling between the circuit components that are expected to increase in high-frequency 3D circuits. Spatially variant anisotropic metamaterials (SVAMs) could be a solution to overcome this …

Characterization Of A Flex-Fuel Oxy-Combustion System Through Experimental Investigation And Computational Modeling, Md Mohieminul I. Khan

Open Access Theses & Dissertations

Oxy-fuel combustion has the potential to offer high thermal efficiency and lower pollutants emission compared to other existing combustion technologies. More than 63% of the worldâ??s electricity is produced by fossil fuel combustion which also is the major reason for greenhouse gas emissions. Oxy combustion offers a solution to it. Oxy combustion uses pure oxygen as an oxidizer instead of air which eliminates the NOx and SOx products from the exhaust. In oxy-combustion flue gas mainly consists of CO2 and water vapor. Furthermore, combustion in presence of pure oxygen results in higher flame temperature and hence promises higher thermal efficiency. …

Optimization Of Lattice Structure Using Machine Learning Approach, Tanzila Bint Minhaj

Open Access Theses & Dissertations

The goal line of designing any structure is to get maximum performance at minimum cost. Therefore, optimization is the only method to achieve that objective. Engineers have been practicing different formats of optimization. Topological optimization is one of the well-known long-practiced methods. But it is always desired to find the most helpful design method that considers every relevant parameter associated with the structure. In the continuation of this search to enhance the efficacy of design through optimization, a new approach was explored in the following work. The motivation was to enable a model to be capable of finding out the …

Diverse Effects Of Ev Charging Infrastructure On Electric Power Distribution Systems, Travis Michael Moore Newbolt

Open Access Theses & Dissertations

The advanced technology of today has allowed for an avenue into cleaner forms of energy that will not only protect our environment but also continue to advance our society. Among the many forms of clean energy, electric vehicles (EV) have the potential to mitigate our consumption of fossil fuels in vehicle transportation industries. In the U.S. for 2021, EVs account for approximately 700,000 registrations. That number is projected to increase to 2 million by 2030. Although EVs do reduce the number of emissions when compared to an internal combustion engine, they do however shift the responsibility to utility companies to …

Characterization Of 3d Printed Parts Containing Integrated Functionality Via Ultrasonically Embedded Wires, David Abraham Sepulveda

Open Access Theses & Dissertations

Material extrusion additive manufacturing has been widely adopted because it offers freedom of design, which allows complex geometry fabrication, and rapid prototyping. Interest in producing components with integrated functionality allowed forms of hybrid manufacturing to be developed such as the Multi3D system. This system produces parts with embedded components by combining additive, subtractive, soldering, dispensing, and embedding techniques. However, this involves pausing the printing process (which takes place in a controlled environment) and exposing it to ambient temperature where embedding takes places. In this research, the effect of embedding parts with 24 AWG copper for improved functionality was quantified mechanically. …

Reflectance Spectral Characterization And Taxonomy Applications Of Spacecraft Materials To Aid Space Situational Awareness, Jacqueline Andrea Reyes

Open Access Theses & Dissertations

The increasing number of space missions involving successfully deployed spacecraft have resulted in an augmented density of artificial objects positioned in orbital domains near Earth. With this steady accumulation of objects in space, it has become increasingly imperative to characterize spacecraft materials, which may ultimately be contributors to the orbital debris population. In an effort to identify unique material-specific spectroscopic markers, a variety of spacecraft materials frequently utilized in the aerospace industry to construct typical spacecraft were analyzed using reflectance spectroscopy as a characterization technique for assessment on material type according to optical features. This is significant in providing information …

Trade Study Analysis Of The Janus Moon Lander Vehicle, Omar Vazquez

Open Access Theses & Dissertations

Liquid Oxygen (LOX) and Liquid Methane (LCH4) has become a propellant combination of interest in the recent years, especially for leading aerospace companies with the sight set on mars such as SpaceX and Blue Origin in their heavy thrust engines (the Raptor and BE-4 respectively) since methane can be more stable than hydrogen, can be stored at more manageable temperatures and can be produced locally, at mars, using in-situ resource utilization (ISRU) [1].The Center for Space Exploration and Technology Research (cSETR) has developed a 500 lbf throttleable (4:1) thrust chamber (CROME) using the aforementioned propellant combination with the intention of …

A Comparable Analysis Of Civilian And Military Airfield Runway Design Procedures, Jacob Wessel

Open Access Theses & Dissertations

In the United States there are two primary agencies that regulate, approve, and aid in airfield runway designs. These two agencies are the Federal Aviation Administration (FAA) and the Department of Defense (DOD), and they both have different design procedure for design and construction of their prospective airfield runways. It is important to have a closer look at the design procedures, the reliance of software and how these compare to each other. The primary objective of this research was to conduct a sensitivity analysis of the FAA and the DOD airfield design programs used to aid in the design of …

Multi-Material/Fiber/Particulate Selective Laser Sintering System Capable Of Local Composition Control And Material Gradients, Jonathan James Slager

Open Access Theses & Dissertations

Multi-material (M2) manufacturing with functional gradients and local composition control (LCC) is an emerging technology with high demand in numerous industries. This research investigated multi-material technology that has potential impact to joint implants, synthetic joints, and damage resistant parts. Novel manufacturing subsystems within established selective laser sintering (SLS) additive manufacturing processes were pioneered to enable printing M2 parts with LCC and functionally graded materials. Powder bed fusion (PBF) material blends consisting of low temperature thermoplastics, low temperature thermoplastic elastomers (TPE), carbon fibers (CF), and hydroxyapatite (HA) particulates were explored to match the designed and tested M2 SLS prototype. M2 sintering, …

Biological Interaction Of Mn-Based Nanomaterials With Capsicum Annuum L. Under Salinity Stress, Yuqing Ye

Open Access Theses & Dissertations

The foliar application of nanomaterials as a method to overcome abiotic stress is relatively new compared to their use as fertilizers or pesticides in agricultural practice. It is also vital to understand the interface between leaf and nanomaterials, as nanomaterials might translocate into crop edible tissues, thus, causing potential toxicity in living beings during food consumption. In this dissertation, salt-stressed Capsicum annuum L was exposed to manganese (Mn) -based nanomaterials (Mn2O3 nanoparticles (MnNPs) and graphene quantum dots doped with Mn (GQD-Mn)) at different stages (seed germination and full life cycle). The dissertation focuses on investigating the mechanism of how Mn-based …

An Unmanned Surface Vehicle: Autonomous Sensor Integration System For Bathymetric Surveys, Fernando Sotelo Torres

Open Access Theses & Dissertations

Unmanned Surface Vehicles (USVs) have been applied to earth sciences, with only a few studies conducted in water environments, as these systems provide autonomous measurement capabilities and transferability to other environmental settings. In this thesis, a reliable, yet economical, USV has been developed for bathymetric surveying of lakes. The system combines an autonomous navigation framework, environmental sensors and a multibeam echosounder to collect submerged topography, temperature, windspeed and monitor the vehicle status during prescribed path planning missions.

The main objective of this study is to provide a methodological framework to build a USV, with independent decision-making, efficient control, and long-range …

Efficient Approaches To Steady State Detection In Multivariate Systems, Honglun Xu

Open Access Theses & Dissertations

Steady state detection is critically important in many engineering fields such as fault detection and diagnosis, process monitoring and control. However, most of the existing methods are designed for univariate signals. In this dissertation, we proposed an efficient online steady state detection method for multivariate systems through a sequential Bayesian partitioning approach. The signal is modeled by a Bayesian piecewise constant mean and covariance model, and a recursive updating method is developed to calculate the posterior distributions analytically. The duration of the current segment is utilized to test the steady state. Insightful guidance is provided for hyperparameter selection. The effectiveness …

Variations In Copper Form Exposure Differentially Modulate Zea Mays (Corn) Physiological Responses, Carolina Valdes Bracamontes

Open Access Theses & Dissertations

In the present study, Zea mays seedlings grown under nano Cu(OH)2 (nCu), bulk Cu(OH)2 (bCu), and ionic CuSO4 (iCu) compound exposure were harvested after six days. The nutritional profile was determined to be significantly disrupted in the roots by 1000 ppm bCu treatment, resulting in a 58.7% reduction in potassium compared to the control. In the shoots, a significant decrease of manganese was observed for 10 and 1000 ppm iCu treatments with 55.7% and 64.2% reductions, respectively. The overall protein content and catalase (CAT) enzymatic activity, however, remained unaffected in either roots or shoots, while an absence of polyphenol oxidase …

Development Of A Custom, 3d-Printed, Multi-Microphone, Noise-Cancelling, Hearing Protection Device With A Magnetically Attached Printed Ear Canal For Sound Localization Preservation, Brenda Leticia Valadez Mesta

Open Access Theses & Dissertations

Hearing loss is a prominent health issue that affects a significant fraction of the global population. One of the main causes behind hearing loss is exposure to harmful noise levels in the workplace. There have been multiple efforts to prevent hearing loss from excessive noise in occupational settings, such as hearing conservation programs and use of hearing protection devices (HPDs), however, these are often ineffective. Although HPDs are frequently available in the workspace, they are not used as intended since they usually generate discomfort and hindered sound localization. The loss of sound localization can be hazardous in occupational settings, since …

Comfort Evaluation Of A Customized Additively Manufactured Headset, Rene Alexis Dominguez

Open Access Theses & Dissertations

Comfortability and end user satisfaction are two of the main objectives in any human-centered product. This is especially important when the product requires interaction with the human head and with the brain. For this research, a customized wearable headset fabricated using additive manufacturing (AM) techniques along with three commercial head devices were analyzed to provide an evaluation of comfort and determine the factors that affect comfort score. The customized headset protects users from dangerous sound frequencies and levels that can permanently damage the human ear (around 82 dB, for extended periods of time). This device is designed to preserve spatial …

Analysis Of Factors Affecting Maternal Health Using Data Mining Techniques, Prajina Edayath

Open Access Theses & Dissertations

Despite being the most expensive maternity care globally, the US has one of the highest maternal mortality rates among developed countries. Furthermore, maternal mortality (MM) and severe maternal morbidity (SMM) have increased in the US during the past two decades. The poor maternal outcome has several contributors. Several socioeconomic and sociodemographic factors impact poor maternal health outcomes and disparities in (MM) and (SMM). However, 45 - 60% of all maternal deaths and SMM cases are preventable with timely and appropriate care. Thus, maternal health outcomes result from multilevel contributors, which suggests that there are opportunities to improve health service quality. …