Engineering Commons^™

The Effect Of K2co3 Concentration In Kerosene Emulsions On Spray Droplet Sizes For A Magnetohydrodynamic Power Generator, Alejandra Castellano

Open Access Theses & Dissertations

Potassium carbonate (K2CO3) is an effective seeding material to introduce potassium vapor in oxy-fuel combustion to create a conductive plasma. Injecting potassium carbonate before combustion promotes particle volatilization and improves the generation of potassium vapor. This can be achieved by emulsifying a potassium carbonate solution with kerosene. Several studies have investigated creating stable emulsions with kerosene with water by using differing surfactants. However, the effects of using varying concentrations of K2CO3 dissolved in deionized water have not been fully explored. Based on methods of creating successful emulsions, the development of a successful mixture comprised of kerosene and K2CO3 solution is …

Regulation Of Schlafen 11 Expression, Christian Waldemar Corona Ayala

Open Access Theses & Dissertations

Schlafen 11 (SLFN11) is a member a family of proteins that can be found in mammals. Members of this family are involved in important functions. SLFN11 in particular has been identified as a restriction factor for several evolutionarily disparate viruses such as HIV-1 and Flaviviruses and to play an important role in DNA repair, sensitizing cells to chemotherapy. Despite its relevance SLFN11 remains largely uncharacterized. The aim of this research was to achieve a more comprehensive understanding the regulation mechanism of SLFN 11 expression. Before our research, it was only known that type I interferon (IFN) regulates SLFN11 levels. However, …

To Or Through The Skin: A Rational Design Of Transdermal Drug Delivery, Isaac Giovanni Deaguero

Open Access Theses & Dissertations

The skin is the largest organ in the body and plays many crucial roles through diverse functions ranging from protection, temperature regulation, energy storage via fat deposits, and is used to communicate with our surroundings. Various methods have been attempted to deliver drugs to target areas of the skin in effective dosages by a variety of means with limited success. Recently, advances in transdermal drug delivery have offered avenues previously unattainable through conventional means. Some of these new delivery methods have been reviewed, explored and offer promising results with the potential to carve a new avenue in the way therapeutic …

Development And Characterization Of Perovskite Solar Cells For Tandem Device Configuration, Angel Moiseis De La Rosa

Open Access Theses & Dissertations

Photovoltaic devices based on perovskite materials are constantly progressing towards more applicability in large-area panels. In order for perovskite-based photovoltaics to reach reliable and stable commercialization, common issues with the use of perovskite still need to be resolved, including the need to identify fabrication processes that can yield optimal material parameters for better photovoltaic performance. Defining an optimal fabrication process requires that researchers and manufacturers alike come to an agreement regarding perovskite characteristics that result from device operation and material processing. This work focuses on characterizing physical, electrical, and electronic properties of a FAxCs1-xPb(IyBr1-y)3 perovskite, and how some of these …

Structural Analysis Of Deformed Caprock Associated With A Salt Shoulder At Gypsum Valley Salt Wall, Paradox Basin, Colorado, Hanah Draper

Open Access Theses & Dissertations

This study documents the style and distribution of deformation present in Triassic-age gypsic and carbonate caprock associated with the Gypsum Valley Salt Wall Salt Shoulder in the Paradox Basin, Colorado in order to determine the mechanism and timing of deformation. Mapping of gypsic and carbonate capstone facies shows that the caprock layering that was generated during formation has been deformed by large-and-small-scale folding and faulting, brecciation, and boudinage. Deformation within the caprock resulted in widely variable orientations along the length of the salt shoulder, that also varies locally in intensity of deformation and with proximity to the passively rising diapir …

Thermoanalytical Studies On The Decomposition Of Energetic Ionic Liquids, Alan Esparza

Open Access Theses & Dissertations

Hydrazine has been extensively used as a propellant for space applications for more than half a century. However, its hazardous characteristics cause high storage and handling costs. For this reason, the search for alternatives, the so-called “green monopropellants,” is of great interest. Most green monopropellants are mixtures of an oxidizer and a fuel, and several ionic liquids (ILs) have been proposed for this application. Among them, hydroxylammonium nitrate (HAN) and 2-hydroxylethylhydrazinium nitrate (HEHN) are promising oxidizer and fuel, respectively. The objective of the present work was to clarify the decomposition kinetics of both HAN and HEHN, using thermogravimetric analysis (TGA), …

Extracting Mechanical Properties Of Compacted Geomaterials Using Intelligent Compaction Technology, Aria Fathi

Open Access Theses & Dissertations

The primary tool currently used for quality management of earthwork and unbound aggregates is the nuclear density gauge (NDG) to ensure appropriate density and moisture content. Measurement of moisture content and dry density, even though quite practical and straightforward, does not directly tie the construction quality with the mechanistic-empirical design processes where stress and modulus are employed. With the recent popularity of the mechanistic pavement design procedures, research efforts have been undertaken to understand and develop procedures for implementing modulus-based quality control (QC) procedures of compacted geomaterials. These procedures involve the use of in-situ nondestructive testing (NDT) devices that estimate …

Independent And Simultaneous Control Of Electromagnetic Wave Properties In Self-Collimating Photonic Crystals Using Spatial Variance, Jesus Javier Gutierrez

Open Access Theses & Dissertations

Photonic crystals are engineered periodic structures that provide great control over electromagnetic waves. One of these mechanisms is self-collimation, in which the electromagnetic wave travels through the photonic crystal along an axis of the lattice without diffracting or spreading. This mechanism of self-collimation is a dispersion phenomenon, which is dependent on the unit cell's physical and geometrical characteristics. An algorithm for generating spatially variant lattices (SVL) was developed that can change geometrical properties in photonic crystals as a function of position, like unit cell orientation, fill fraction, symmetry, and others in a manner that is smooth, continuous, and virtually free …

A Cellulose-Based Biological Sensor For The Quantitative Determination Of Glucose And Glycated Hemoglobin (Hba1c), Gilberto Henao-Pabon

Open Access Theses & Dissertations

ABSTRACT

Importance: Diabetes is a common world-wide disease characterized by insulin resistance and as result there is an increased risk of cardiovascular disease and other metabolic abnormalities, that contribute to irreversible end-organ damage. The cause of diabetes is multifactorial and includes genetic, inflammatory and environmental factors plus lifestyle issues. Because in diabetes there are high levels of glucose and glycated hemoglobin, these molecules are used in clinical settings for the acute and chronic management of diabetic patients.

Objectives: a. To design and build an electrochemical biological sensor using the enzyme Glucose Oxidase (GOX) to detect glucose in biological fluids.

b. …

The Study Of The Mouse Schlafen Family Members As Mediators Of Antiviral Activity, Julia Fernanda Hernandez

Open Access Theses & Dissertations

The Schlafen family of proteins was first characterized in 1988, and since then evidence of their relevance in different physiological and pathological situations have been accumulating although at a slow pace. Hence, the biological roles of these proteins remain ill-defined. The expression of these proteins is positively regulated by type 1 interferons, constituting a component of the innate immune response. Functions of these proteins vary from regulation of cell proliferation to restriction of viral infections. Recent studies have implicated SLFN11 and SLFN13 as inhibitors of HIV-1 infection2-4. The mechanism of action of SLFN11 resides in its capacity to regulate the …

Laser Diagnostics Of Compressible And High-Intensity Premixed Methane-Air Combustion Inside A Backward Facing Step Combustor Using High- Repetition Rate Ch-Plif And Piv, Md. Amzad Hossain

Open Access Theses & Dissertations

A novel high repetition rate (10 kHz) planar laser-induced fluorescence (PLIF) diagnostic technique was used for the flame front study. Premixed methane-air combustion was studied at different flow turbulence conditions (Re = 15000, 30000 and 64000; 12CFM, 25CFM and 50 CFM; 10m/s, 20 m/s and 40 m/s) and fuel loading (Փ =0.6 to 1.2). The study used an optically accessible backward-facing step high-speed combustor. Methane-air mixture was supplied to the combustor at atmospheric pressure and standard room temperature (T =25°C). CX-CH PLIF was used to detect the actual flame front structures. The flame dynamics were then correlated to the flow …

An Accelerated Creep Testing Program For Nickel Based Superalloys, Robert M. Mach

Open Access Theses & Dissertations

In order to improve the energy production within the United States, new materials are developed with the goal of increased functionality. These materials are required to perform at extreme pressures and temperatures (up to and beyond 200MPa and 650â??) as well as be sustainable beyond 105 hours. Before developing these materials into components for power generation, mechanical testing is required to better understand the behavior of these materials at various loads and temperatures. The longest of these tests is the conventional creep test which is a real time test that can beyond 105 hours depending on service conditions. Hundreds of …

Development Of The Payload System And Obc Microcontroller Coding For A Cubic Satellite Performing An Additive Self-Repair Experiment In Space, Eduardo Macias-Zugasti

Open Access Theses & Dissertations

Additive manufacturing, which is also known as three-dimensional printing, in space is one of the most promising technologies advancing current capabilities for in-orbit space manufacturing and assembly. Additive manufacturing contributes to the reduction of cost per kilogram and number of launches, thus facilitating extraterrestrial colonization and deep-space exploration. The state of the art includes advancing efforts inside the International Space Station (ISS). However, the ISS is a controlled environment and, to the best of our knowledge, no spacecraft or satellite has performed additive manufacturing tasks in the extreme environment of outer space. In this work a 1U CubeSat named Orbital …

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 …