Engineering Commons^™

Compound Vision Approach For Autonomous Vehicles Navigation, Michael Mikhael

Open Access Theses & Dissertations

An analogy can be made between the sensing that occurs in simple robots and drones and that in insects and crustaceans, especially in basic navigation requirements. Thus, an approach in robots/drones based on compound eye vision could be useful. In this research, several image processing algorithms were used to detect and track moving objects starting with images upon which a grid (compound eye image) was superimposed, including contours detection, the second moments of those contours along with the grid applied to the original image, and Fourier Transforms and inverse Fourier Transforms. The latter also provide information about scene or camera …

Velocity Measurements Using A Piezoelectric Plate As A Sensor, Paul Perez

Open Access Theses & Dissertations

In this study, the voltage output from a piezoelectric sensor placed in a test section is used to predict flow velocity changes. The piezoelectric made of PZT is thought to be advantageous due to its fast response time, potential durability at higher temperatures, and self-powered characteristics. Having said that this sensor could be implemented into the Hybrid Performance Project built by NETL to characterize and mitigate the probability of compressor surge and stall. The problem arises because of the added large volume between compressor and gas turbine and resultant changes to system fluid dynamics. The effect of the piezoelectric sensor …

Design And Characterization Of Thermal Inkjet Bioprinted Constructs For The Treatment Of Diabetic Foot Ulcers And Other Wound Healing Impaired Conditions, Luis Horacio Solis

Open Access Theses & Dissertations

Tissue engineering (TE) is a multidisciplinary practice focused on developing patient-specific constructs to repair, regenerate, or replace injured tissues and organs. One biofabrication process that has gained tremendous momentum in this field is bioprinting. Most, if not all bioprinting modalities embody the same principles of heat and shear due to mechanical forces or friction as cells are forced through narrow orifices. While it is important to examine the interaction between host and implanted constructs, it is also crucial to understand the direct effects that these bioprinting technologies have on cells before embedding them into TE applications.

The purpose of this …

Development Of A Framework For The Calibration Of Rpas, A 3d Finite Element Analysis Tool For Rigid Pavements, Abbasali Taghavighalesari

Open Access Theses & Dissertations

The accurate analysis of rigid pavements requires a reliable modeling procedure based on integrating mechanistic analysis methods (i.e. closed-form solutions or numerical methods) and empirical observations (i.e. field measurements and laboratory test results). The use of the finite element method to model the response of rigid pavements has increased in recent decades due to its capability to incorporate the complexity of material behavior, traffic information, and environmental condition. Researchers from the University of Texas at El Paso developed the software Rigid Pavement Analysis System (RPAS) to comprehensively analyze the response of concrete pavements under different geometric configurations, foundation models, temperature …

Computational Methods For Creep Modeling, Ricardo Vega

Open Access Theses & Dissertations

Creep is an important phenomenon present in the power generation and aerospace industry. Creep is a mechanism that degrades the quality of a part, such as the turbines used in different industries, when elevated temperatures and loads are applied. Creep damage can cause critical failures that can cost millions of dollars and as such, prevention is important. A multitude of creep models exist to help with design and failure prevention. These models are applied using computational tools which allows the engineer to properly predict the life of a part or other material properties. In this work various creep numerical optimization …

Impact Of Interface Condition On Performance Of Thin Asphalt Overlays, Cheng Zhu

Open Access Theses & Dissertations

Asphalt overlay has been widely used in the United States as a cost-effective maintenance approach to keep the pavement in a satisfactory condition. In recent years, many studies have been conducted to investigate the overlay asphalt mix design, overlay pavement design, and quality control/quality assurance for the asphalt overlay pavement. In Texas, thin overlays (lift thickness less than 2 in.) and ultra-thin overlays (lift thickness of 0.5 in. to 0.75 in.) seem to be more beneficial than conventional asphalt overlays. For this type of overlay, the bonding condition between the overlay and existing AC layer is crucial for the pavement …

Development Of A Mems Fabrication Process On Soi To Study High Strain In Transition-Metal Dichalcogenides, Edgar Acosta

Open Access Theses & Dissertations

Over the recent years there has been an increasing demand of better performing electronics. However, as the semiconductor industry keeps on improving and scaling the technology to the nanometer regime, the passive power density has overcome the overall power consumption of transistors. The inability to reduce the power alongside the scaling of transistors has led the scientific community in the search for alternatives or different solutions to overcome this power crisis. The use of two-dimensional Transition-Metal Dichalcogenides (TMDCS) and Micro-Electro-Mechanical System (MEMS) actuators, in conjunction, has been proposed as an alternative solution [1]. Recent studies of TMDCS have shown a …

Tram System Automation For Environmental Spectroscopy And Vegetation Monitoring, Enrique Anguiano Chavez

Open Access Theses & Dissertations

Spectroscopy is the science of studying the interactions of matter and electromagnetic radiation (EMR). In particular, field spectroscopy takes place in a natural environment with a natural source of EMR. The paper presents progress towards the development and automation of a tram cart system. The new system in development collects high resolution, hyperspectral images and data from a spectrometer. Alternatives for a sensor cover mechanism to provide cover for the sensors mounted while the system is not operating are discussed, analyzing and comparing the benefits and disadvantages. An implementation for a charging station in an environment isolated from the electric …

A Performance-Based Analysis Of Balanced Mix Designs, Elias Aaron Castillo

Open Access Theses & Dissertations

The Superpave design procedure was established to provide a more representative design methodology and to minimize typical pavement distresses such as fatigue cracking and permanent deformation. This Superpave design methodology was developed on the premise that the voids in mineral aggregate can evaluate the quality and constructability of asphalt mixture during the design and production phases. With the increased use of recycled materials, recycling agents, modified binders and warm mix asphalt additives, several highway agencies including the Texas Department of Transportation (TxDOT), have investigated whether the Superpave volumetric-based design method is enough to ensure appropriate performance of the final product. …

High Pressure High Heat Flux Pool Boiling Test Facility Design To Investigate Nucleation Boiling Heat Transfer Enhancement Using Micro/Nano-Scale Engineered Structures, Omar Hernandez Hernandez Rodriguez

Open Access Theses & Dissertations

Developing efficient heat dissipation technologies is of critical importance towards the development and the commercialization of next-generation compact and high-performance electronic devices, cooling systems, power generation systems and chemical processing units, as well as retrofitting the existing thermal management schemes. As such, phase change heat transfer systems, more specifically boiling heat transfer systems, have attracted significant attention due to their ability to extract a large amount of latent energy stored within the fluid. Pool boiling is an efficient mode of phase change heat transfer processes accompanied by nucleation of vapor bubbles from liquid on to the hot surfaces, bubble growth, …

A Comparison Of Data-Driven And Process-Based Modeling For Nutrient Estimation In A Eutrophic Reservoir, Yohtaro Kobayashi

Open Access Theses & Dissertations

As land use around bodies of water changes, the need to model the body of water increases. Models help to educate, understand, and predict the state of water. Process-based models are commonly used in modelling bodies of water, but there are challenges with these kinds of models. They require data which can be difficult for certain communities to obtain due to logistics or cost, are computationally intensive, technically complicated, and require calibration. In contrast, a data-driven model simply connect relationships from the data, are not as computationally intensive nor technically complicated, and do not require calibration. This research compared a …

Weather Prediction: Improving Accuracy Using Data Mining And Forecasting Techniques, Pedro Marquez

Open Access Theses & Dissertations

This study is focused to provide the insights of weather to understand the significance of weather changes in any parameter. Weather forecasting contributes to the social and economic welfare in many sections of the society. Weather is extremely difficult to predict because it is a complex and chaotic system. This means that small errors in the initial conditions of a forecast grow rapidly and affect predictability. Nowadays, massive real-time data is being generated by IoT devices, radars, weather stations, and satellites. The need to adopt big data analytics in IoT applications is compelling. These two technologies have already been recognized …

Development Of A Multi-Axis Wire Embedding Device For A Large Area Thermoplastic Pellet-Fed Additive Manufacturing System, Christopher Jasiel Minjares

Open Access Theses & Dissertations

This research focused on the development and implementations of a six degrees of freedom (6DOF) articulated arm onto a Big Area Additive Manufacturing (BAAM) system to interact with complex 3D geometries. BAAM is a large-scale machine which falls under material extrusion additive manufacturing (AM) - a process that selectively dispenses molten plastic layer-by-layer. The development of the 6DOF articulated arm required a mechanical design which went through several iterations before getting to the final design. Also, implementation of the tool was performed with the help from Cincinnati Incorporated (CI) which is the company that developed the BAAM.

First, the mechanical …

A High-Temperature Valve Design For A Solid Oxide Fuel Cell/Gas Turbine Hybrid System, Cynthia Morales

Open Access Theses & Dissertations

Systems containing high heat generation require thermal management, especially in a solid oxide fuel cell gas turbine (SOFC/GT) hybrid system. The startup of each system in a standalone configuration may be a trivial approach, but when coupled together, different dynamics are experienced. The SOFC/GT provide high theoretical efficiency due to the ability to recover the extra heat produced by the fuel cell (FC) to drive the gas turbine (GT). After recovering the energy recuperated in the GT, the exhaust gas heats the cathode inlet flow to the FC which is an advantage during nominal operation of the cycle but not …

Relating Surface Resistivity To Corrosion Of Rebar Embedded In Portland Cement Concrete, Luisa Alejandra Morales

Open Access Theses & Dissertations

Reinforced concrete is widely used as a construction material known for its durability and proficiency of withstanding large forces in severe environments. Despite that the majority of these structures result in long-term performance, there is still a large number of failures of reinforced concrete structures as a result in corrosion of the reinforcement and concrete degradation. It is critical to assess the state of the corroded structure to decide on whether maintaining or replacing the structure is needed. The objective of this study is to characterize a relationship between the steel reinforcement corrosion and the concrete's resistivity. It is widely …

Quantifying Spatiotemporal Patterns Of Past And Future Urban Trends In El Paso, Tx And Their Impact On Electricity Consumption Using Nlcd Data And The Ca-Markov Model, Joanne Michelle Moyer

Open Access Theses & Dissertations

As cities continue to grow, their urban form continues to evolve over. Understanding this evolution allows for planners, engineers, and decision makers to plan for a sustainable community. Change analysis was conducted for El Paso, Texas county to determine the areas of growth within the past 15-years (2001-2016). The results indicate that growth has primarily occurred within the city of El Paso, in particular Districts 5 (east side), 1 (west side), and 4 (northeast), with District 5 experiencing substantial growth. Developed sub-categories medium and High intensity experienced the fastest growth, which represents single-family housing and compact/commercial areas. However, landscape metrics …

Oxidation Of Niobium Silicides Obtained By Self-Propagating High-Temperature Synthesis, Frank Anthony Perez

Open Access Theses & Dissertations

Niobium silicide-based composites are promising materials for high-temperature structural applications, such as gas turbines. One attractive method for their fabrication is mechanically activated self-propagating high-temperature synThesis (MASHS). However, oxidation resistance of niobium silicides produced by MASHS has not been studied yet. In this present work, the oxidation of Nb/Nb5Si3 composites obtained by MASHS was investigated by using non-isothermal thermogravimetric analysis (TGA) and differential scanning analysis (DSC). Both techniques have shown that the oxidation starts at about 500 °C and the materials become fully oxidized at 750 â?? 800 °C. Model-based analysis of the TGA data has shown that the Avrami-Erofeev …

Synthesis And Characterization Of Novel Lithium Gallium Phosphate (Ligap2o7) For Extreme Environment Applications, Mohan Raj Rajkumar

Open Access Theses & Dissertations

In this work, we report on the synthesis, characterization, and performance of LiGaP2O7 (LGP), a novel material and fairly new to the scientific & engineering community. LiGaP2O7 materials were was synthesized using the conventional high-temperature, solid-state ceramic reaction. Calcination was done in three steps at the temperatures of 300 °C, 500 °C, and 650 °C for 8 h each to ensure a single phase. Utilizing this, different green pellets were sintered at 800 °C for varying times of 3 h, 6 h, 12 h, and 24 h. The structure, phase, and morphology were analyzed using X-ray diffraction (XRD) and scanning …

Multi-Wavelength Pyrometry For Emissivity Mapping And Accurate Surface Temperature Measurement In Powder Bed Fusion Systems, Md Moinuddin Shuvo

Open Access Theses & Dissertations

Accurate surface temperature measurement within powder bed fusion (PBF) systems during fabrication remains elusive for many reasons, despite the importance of knowing temperature for improving part quality, process control, repeatability and reproducibility, simulation capabilities, and more. Multi-wavelength (MW) pyrometry has been used previously to measure off-axis temperatures of a small region (~2.6mm in diameter) within an electron beam PBF (EBPBF) system. While this small region measurement makes it difficult to get a full field temperature map of the powder bed, it also allows for inline (on-axis) with laser temperature measurements for laser PBF (LPBF) systems. The MW pyrometry technique determines …

Mechanically Activated Combustion Synthesis Of Niobium Silicide Based Composites, Reina Trevino

Open Access Theses & Dissertations

Niobium silicide-based composites are promising materials for high-temperature structural applications, such as gas turbines, but their implementation is hindered by the lack of effective processing methods. Self-propagating high-temperature synThesis (SHS) is an attractive method for fabrication of advanced materials. However, it is difficult to perform SHS of niobium silicides because the melting point of Nb is higher than the combustion temperature, which greatly inhibits Nb-Si reaction. To ignite an Nb/Si mixture and obtain Nb5Si3, the desired phase in niobium silicides, either preheating or mechanical activation of the mixture is necessary. This problem becomes even more critical in the SHS of …

Life Cycle Studies To Evaluate The Physiological And Biochemical Effects Of Copper Oxide And Surface-Coated Titanium Dioxide Nanoparticles On Green Onion (Allium Fistulosum) And Carrot (Daucus Carota L.) Plants: Insights Utilizing Two-Photon Microscopy And Spectroscopy, Yi Wang

Open Access Theses & Dissertations

With the recent increase of nanomaterial production, nano copper oxide (nCuO) and surface-modified titanium dioxide nanoparticles (nTiO2) are among the most widely applied nanoparticles in industry and daily lives. Their use has resulted in accumulation in soils as a consequence of their direct or indirect release. Hence, these NPs may raise a potential risk to crops cultivated in soils. Moreover, the physiological effects of nCuO on green onion (Allium fistulosum) and surface-coated nTiO2 on full-grown carrot (Daucus carota L.) are still unknown. Green onion is characterized by its high content of the antioxidant allicin, and carrot is a worldwide economic …

Qualification And Implementation Of A Liquid Oxygen/ Liquid Methane Data Acquisition System, Zachary Welsh Welsh

Open Access Theses & Dissertations

One of the primary goals of the MIRO Center for Space Exploration and Technology Research (cSETR) is the design and testing of liquid oxygen and liquid methane rocket engines. As of this thesis’ time of writing, two engines are currently undergoing testing at the center’s Technology Research and Innovation Acceleration Park (tRIAC), located in Fabens, Texas. The engines vary in scale starting with a 5 lbf Reaction Control Engine (RCE) to a 500 lbf engine dubbed the Centennial Restartable Oxygen Methane Engine (CROME). It was necessary to develop a control and data acquisition system to support these various test campaigns, …

Multiple Change-Point Modeling Of Degradation Signal For Prognostics Improvement, Yuxin Wen

Open Access Theses & Dissertations

To fulfill the increasing demand on functionality and quality, modern engineering systems are usually built with overwhelming complexities. The more complex functions the system has been built, the higher reliability required of the system. This is mainly due to the fact that a single failure can result in catastrophic consequences. Therefore, methods that can predict and prevent such catastrophes have long been explored. Prognostics refer to the process of evaluating the current health of a system or a component and then predicting the remaining useful life (RUL) based on the information collected through condition monitoring. The fast development of information …

Effect Of Flow Velocity And Geometry On The Signal From A Piezoelectric Flow Rate Sensor, Jad Gerges Aboud

Open Access Theses & Dissertations

.

Forecasting Consumer Consumption Behavior Of Water Bottles Using Generlized Linear Model For Supply Chain Resilience, Abdulaziz Alidrees

Open Access Theses & Dissertations

When forecasting the amount of water consumed by individuals at Kuwait's Mubarak Al-Kabeer city Block 8, it is important for any water producing company to tell the amount of water they should produce for its target consumers. After interviewing a couple of residents in this block, it was discovered that they were restricted by being unable to shop for their essentials, including water packs. Data on the amount of water consumption in milliliters for different individuals were collected and recorded. Generic scanners and smartphone scanners were installed in 20 different households that rely on water packs instead of central water …

Accurate Replication Of An Ear Pinnae Geometry For Use In Acoustic Testing Of Spatial Cues And Sound Localization, Alejandra Belmont

Open Access Theses & Dissertations

Additive manufacturing (AM) enables freedom of design as well as fabrication of complex objects such as the human hear. In medical modeling there is a need for patient-specific customizable parts. The outer human ear consists of these main parts: the pinna, which naturally filters sound, and the ear canal, which is the point at which sound enters before being moved up to the tympanic membrane, otherwise known as the eardrum. In an attempt to accurately replicate ear models, the use of scanning and reverse engineering methods was used. A comparison of 3D laser scanning systems was performed to determine their …

The Dynamic Transition Of A Vertical Take-Off And Landing Drone, Luis Carlos Calvo Jr.

Open Access Theses & Dissertations

Unmanned aerial vehicles, or UAVs, are small pilotless aircrafts that are remotely controlled through a ground control station. They have increased in popularity because of their applications and the advantages that each UAV can provide based on their need. There are many types of UAVs, but this study focuses on a type of Vertical Take-Off and Landing (VTOL) UAV that is known as the Albatross UAV. This UAV was manufactured by a company known as Applied Aeronautics, and configurations were made to change the fixed-wing (FW) UAV to a VTOL UAV. This study was done to find methodologies to simulate …

Design And Additive Manufacturing Of Shape Recovery Polymer Lattice Structure, Chien-Chun Chou

Open Access Theses & Dissertations

Studied mechanical properties of 3D printed metamaterials of BCC, FCC, and BFCC structure.

Mathematical Modeling, Optimal Control And Stability Analysis For Dynamic Supply Chains, Yasser Alberto Davizon

Open Access Theses & Dissertations

Dynamic supply chains (SC) are important to reduce inventory, to enable the flow of materials, and maximize profits. By this, dynamic SC require proper decision-making with effective performance and synchronization. In operations and production planning processes, decision-makers develop convenient and suitable decisions, to validate their hypoThesis about which decisions incorporate more profit while reducing costs on enterprise operations. Based on this, inventory management plays a crucial point in the supply chain analysis. In general, SC processes raw material, cash, and information flows, taking into account the demand profile of the system. This research work presents the mathematical modeling, optimal control, …

Development Of Software Tools And Experimental In Situ Electron Spin Resonance For Characterizing The Magnetic And Electrocatalytic Properties Of Transition Metal Chalcogenide Crystals, Jose Armando Delgado

Open Access Theses & Dissertations

Studying the magnetic properties and crystal defects of transition metal chalcogenide crystals is of paramount importance for utilizing them for next generation spintronics devices and hydrogen evolution reaction catalysts. Hydrothermally grown transition metal chalcogenide nanocrystals (MoS2, Ru2S3, Rh2S3, Co2S8) were chosen as catalysts for the hydrogen evolution reaction due to their low dimensionality and previous utilization as catalysts for hydrodesulfurization. The relationship between crystal defect sites and catalytic activity must be discerned to maximize the efficiency of hydrogen production during the hydrogen evolution reaction. ESR spectroscopy was utilized as a spin sensitive technique to study the defects and local changes …