Engineering Commons^™

The Use Of Remote Sensing Technologies And Models To Study Pollutants In Pdn Region, Suhail Mahmud

Open Access Theses & Dissertations

Using a suite of modeling techniques and instrumentation we study the atmospheric pollutants in the PdN Region. The first objective of this work was to measure hemi-spherically integrated, spectrally resolved solar photon flux (actinic flux) between the wavelengths 300 and 700 nm, and use the measured actinic flux to improve air quality simulations. Actinic flux was measured in the PdN region in order to calculate photolysis rate coefficients for different pollutants. The improved photolysis rate coefficients were then integrated into a photochemical air quality model (CAMx) in order to improve air quality forecasting. We present the simulations performed for a …

Environmental Dynamics: A Compendium Of Rhetorical Application, Annalisa Perez

Open Access Theses & Dissertations

Technology, albeit exceedingly useful, has exponentially exacerbated the communications dilemma between the technical and the non-technical. Additionally, based on a current new understanding of the term environmental, it can no longer be fully defined by terms such as air, water, waste, or purification. Rather, the meaning of environmental has been globally transformed in several ways. The term environmental is encompassing an expansion of understanding and is further defined with words such as essence, perception, rapport and multi-dimensional spaces. This work, Environmental Dynamics: A Compendium of Rhetorical Application (EDC), provides a framework where communication can be enhanced in areas where communication …

Fabrication And Testing Of Cfrp Composites With Embedded Piezoelectric Particles For Temperature Sensing And Energy Harvesting, Emilio Tarango Valles

Open Access Theses & Dissertations

As a part of this world's continuous evolution and technological advancements, smart materials and functional composites have become an attractive topic. In many cases, these new functional composites are replacing the traditional engineering material due to their customizable mechanical properties. This Thesis analyzes and demonstrates the signal response, sensing capabilities and structural properties from Carbon/Glass Fiber Reinforced Plastic Composites (CFRP) with embedded Lead Zirconate Titanate Particles (PZT). The added PZT particles function as actuators, giving the composites a functionality. The PZT quantity inside each composite was variated to study better and characterize the mechanical and electrical properties; the variations were …

Analysis Of Road Vehicle Aerodynamics With Computational Fluid Dynamics, Christian Armando Mata

Open Access Theses & Dissertations

A road vehicles aerodynamics can be one of the most influential aspects of its performance. With the increased importance on fuel efficiency in recent years, new road vehicles are being developed smaller in size, with smaller displacement engines, as well as with improved aerodynamics. The aerodynamics of a vehicle can have a significant effect on its fuel efficiency, as well as other important aspects of the vehicles performance such as the top speed, acceleration, and handling. A study focusing on analyzing aerodynamic effects due to vehicle geometries such as wheels covered by the vehicles body in comparison to open wheels …

Flame Front Structures Studies Of Highly Turbulent Reacting Flow Over A Backward Facing Step Using Khz Oh-Ch Planar Laser Induced Fluorescence, Arturo Acosta-Zamora

Open Access Theses & Dissertations

In recent years, there has been a greater move in the scientific and political community to increase combustion efficiency and reduce emission levels; for this reason, it is crucial to gain a better understanding of combustion. Experimental work at relevant conditions and the data generated from these is needed in order to gain a better understanding of combustion; this data may also be used for validation and further refinement of computational models and simulations. The improvement of optical combustion diagnostics systems has opened new ways to explore these combustion processes. The testing of a high intensity turbulence combustion system is …

Structural Design Of Liquid Oxygen/Liquid Methane Robotic Lander Janus, Mariana Chaidez

Open Access Theses & Dissertations

As the attempt to send humans to Mars has gained momentum in the last decade, the need to find alternative propellants that are safer, less toxic, and yields a better performance has become apparent [1]. Liquid methane and oxygen have emerged as a suitable alternative. In addition, the incorporation of liquid methane/liquid oxygen into the propulsion system has demonstrated an increase in engine performance, as well as a reduction in the volume, size and complexity of the propulsion system. In an attempt to further understand the technologies that are possible to develop using liquid oxygen (LO2) and liquid methane (LCH4), …

Implementation Of New System For Oxygen Generation And Carbon Dioxide Removal, Angelo Peter Karavolos

Open Access Theses & Dissertations

This research effort develops an integrated system for CO2 removal and O2 production. A unique material, dodeca-tungsto-phosphoric acid (H3PO4W12O3; henceforth referred to as DTPA) is mixed with tetra-ethyl-ortho-silicate Si(OC2H5)4 or TEOS. This mixture exhibits unique properties of heat absorption and high electrical conductivity. In the system described herein, the DTPA resides within a cross linked arrangement of TEOS. The DTPA furnishes a source of O2, while the TEOS furnishes structural support for the large DTPA crystals. In addition, the large amount of H2O within the crystal also adsorbs CO2. It can also be cross-linked with other polymers such as polycarbonate, …

Design Optimization Of Sandwich Core, Mohammad Tauhiduzzaman

Open Access Theses & Dissertations

Ultralight sandwich structures comprising of low-density core with stiff facings have attracted significant research interest for their considerable weight saving applications. The aircraft industries are focusing on decreasing the structural mass to lower the manufacturing and operating costs. Design analysis of the sandwich cores using finite element analysis has been developed as a promising concept to feature sandwich structures with maximum strength, stiffness, and reduced weight. To obtain multifunctional behavior of sandwich panels, a profound investigation of geometrical and mechanical properties in the transverse plane is required because it is very susceptible to any kind loadings. Structural optimization is one …

Creating Multi-Functional G-Code For Multi-Process Additive Manufacturing, Efrain Aguilera Jr

Open Access Theses & Dissertations

Additive manufacturing (AM) started over thirty years ago and with it a manufacturing revolution that moves industrial production into the personal home. With recent interest shifting into multi-functional parts fabricated through AM technologies, unified systems are being developed. Merging different manufacturing technologies into one single machine is a challenge but undergoing research has shown promise in the development of multi-functional systems. Concurrent work is being done in the software, automation, and hardware aspect of multi-functional systems. An effort to use industry compatible Computer Aided Design (CAD) software to design multi-functional parts including circuits, micro-machining, and foil embedding then exporting and …

A Spatially Variant Metamaterial Design Process For Transformation Electromagnetic Devices, Eric Alan Berry

Open Access Theses & Dissertations

A technique for the implementation of devices designed using transformation optics (TO) is presented using metamaterial elements arranged using spatially variant lattices. A description of transformation optics, including the design of arbitrarily shaped devices by solving Laplace's equation numerically, is discussed. Analysis of a variety of metamaterial unit cells using frequency sweeps of the unit cells with the resulting permittivity and permeability values. Metamaterial unit cells are also analyzed by the scaling of all the features of the metamaterial elements in the unit cell and calculating the permittivity and permeability. Finite- difference time domain (FDTD) and finite-difference frequency domain (FDFD) …

Adaptive Switched Capacitor Voltage Boost For Thermoelectric Generation, Rene A. Brito

Open Access Theses & Dissertations

Thermoelectric generators (TEG) and other forms of energy harvesting often provide voltages that are not directly usable by traditional electronics as levels are too low from the TEG. While increasing the number of thermoelectric elements can ultimately increase the power output, there is a tradeoff between size and power. By implementing charge pumps, a proposed circuit technique is described that can boost the TEG output to levels that can be used for energy harvesting applications. Current voltage boost circuits for TEGs simply boost a voltage by a set amount. The proposed circuit consists of an analog chip, to provide several …

A Novel Approach For Evaluating The Impact Of Fixed Variables On Photovoltaic (Pv) Solar Installations Using Enhanced Meta Data Analysis Among Higher Education Institutions In The United States, Diane N. De Hoyos

Open Access Theses & Dissertations

The global demand for electric energy has continuously increased over the last few decades. Some mature, alternative generation methods are wind, power, photovoltaic panels, biogas and fuel cells. In order to find alternative sources of energy to aid in the reduction of our nation's dependency on non-renewable fuels, energy sources include the use of solar energy panels. The intent of these initiatives is to provide substantial energy savings and reduce dependence on the electrical grid and net metering savings during the peak energy-use hours.

The focus of this study explores and provides a clearer picture of the adoption of solar …

A Cracking Methodology To Assess Fracture And Fatigue Properties Of Asphalt Concrete Mixtures Using Overlay Tester, Victor M. Garcia

Open Access Theses & Dissertations

Several highway agencies have either implemented or considered implementing performance tests to predict the cracking potential of asphalt concrete (AC) mixtures in the laboratory setting. One such test, the Overlay Tester (OT) test, measures the number of cycles to failure of the AC specimens by simulating the opening and closing of the cracks induced by daily temperature variations and high tensile strain generated by the traffic load. The variability of the OT test results is expressed as a major concern in reliably characterizing the cracking potential of the AC mixes.

The performance of the OT test, in general, and current …

Numerical Calculation Of Spatially Variant Anisotropic Metamaterial, Asad Ullah Hil Gulib

Open Access Theses & Dissertations

3D printing, or additive manufacturing, is rapidly evolving into a mainstream manufacturing technology that is creating new opportunities for electromagnetics and circuits. 3D printing permits circuits to fully utilize the third dimension allowing more functions in the same amount of space and allows the devices to have arbitrary form factors. 3D printing is letting us discover new physics that is not possible in standard 2D circuits and devices. However, evolving electromagnetics and circuits into three dimensions introduces some serious problems like thermal management, interference, and mutual coupling between the components which degrades performance and hurts signal integrity.

Metamaterials are engineered …

Validation Of An Error Sonification Auditory Feedback Training Program On Proper Sagittal Plane Squat Technique, Rena Hale

Open Access Theses & Dissertations

Osteoarthritis (OA) is one of the most common degenerative joint diseases that hinders an individual's quality of life. A large portion of knee OA instances can be correlated to previous anterior cruciate ligament (ACL) injury. Knee joint injury leading to OA is most prevalent in males aged 20-55 years old and can be caused by improper form during execution of a given task or lack of neuromuscular control. Screening protocols are used to assess deficits of an athlete, with the goal of reducing the risk of injury during both training and in competition. Neuromuscular training programs have been created to …

Liquid-Phase Exfoliation Of Two-Dimensional Graphite For Ink-Jet Printing, Monica Michel

Open Access Theses & Dissertations

Over the last decade, the study of two-dimensional (2D) materials has seen an incredible growth due to their unique thermal, mechanical and electronic properties. Solution phase manufacturing offers a way in which they can be produced at large scale by creating dispersions from the exfoliated material. Once created, different options for assembling devices exist. One technique for large scale manufacturing of materials in this form is ink-jet printing, which is a form of additive manufacturing that has proven to be attractive for the printed electronics industry. One challenge that ink-jet printing still faces is the shortage of inks with appropriate …

Design Of A 500 Lbf Liquid Oxygen And Liquid Methane Rocket Engine For Suborbital Flight, Jesus Eduardo Trillo

Open Access Theses & Dissertations

Liquid methane (LCH4)is the most promising rocket fuel for our journey to Mars and other space entities. Compared to liquid hydrogen, the most common cryogenic fuel used today, methane is denser and can be stored at a more manageable temperature; leading to more affordable tanks and a lighter system. The most important advantage is it can be produced from local sources using in-situ resource utilization (ISRU) technology. This will allow the production of the fuel needed to come back to earth on the surface of Mars, or the space entity being explored,making the overall mission more cost effective by enabling …

Fiberglass Goes Green: Developing Phosphate Glass For Use In Biodegradable Composites, Christina Lee Arendt

Open Access Theses & Dissertations

Composite materials, such as the glass fiber reinforced polyester thermosets known as "fiberglass," are used in many applications. However, recycling processes for these materials are inefficient and not widely available. Specially engineered degradable polymers offer an opportunity to redesign these composites. Additionally, the composite could be tailored to be multi-use, such that upon degradation, the resulting products could be used as part of a zeoponic substrate (artificial soil) for growing plants. Such a material would be beneficial for long-duration space missions, terraforming, or in other agricultural applications.

The research presented in this Dissertation focuses on developing phosphate glass for use …

Effects Of Citric Acid Coated And Uncoated Cerium Oxide Nanoparticles In Tomato (Solanum Lycopersicum) Plants, Ana Cecilia Barrios

Open Access Theses & Dissertations

This research was performed to examine the physiological and biochemical effects of bare (nCeO2) and citric acid coated (nCeO2+CA) cerium oxide nanoparticles in tomato (Solanum lycopersicum). Plants were germinated and grown to full maturity in soil amended with 0-500 mg/kg and periodically analyzed using ICP-OES/MS and other spectroscopic and biochemical techniques. Although Ce in tissues increased as the external nCeO2 increased, there were no visible signs of toxicity. In mature plants, nCeO2 induced developmental changes and altered nutritional quality (essential elements) in fruits. On the other hand, nCeO2+CA affected fruit carbohydrate composition (sugars and starch). This study gives insights on …

Blind Image Deconvolution Based On Sparsity: Theoretical Justification And Improvement Of State-Of-The-Art Techniques, Fernando Cervantes

Open Access Theses & Dissertations

Observed signals and images are distorted by noise and blurring. In precise terms, blurring is a convolution of the original image with some blurring function. From this viewpoint, to reconstruct the original image, we need to reverse the effects of this convolution, i.e., to ``deconvolve'' the image. Many efficient methods for image deconvolution are known. However, most of these methods assume that we know the blurring function -- or at least that we have some partial information about the blurring function. In some practical situations, however, we do not have this information. In such situations, we need to perform, blind …

Minimizing Environmental Impacts For Hub And Spoke Distribution Network Problems Through The Use Of Multi-Objective Evolutionary Algorithms, Ileana Delgado

Open Access Theses & Dissertations

While transportation is crucial to our economy and our personal lives, as a sector it is also a significant source of greenhouse gas (GHG) emissions. The AASHTO report states, "America's transportation system has served us well, but now faces the challenges of congestion, energy supply, environmental impacts, climate change, and threatens the economic, social, and environmental future of the nation". With respect to the environment, transportation is the most visible aspect of supply chains. Transportation emissions can be reduced by implementing approaches that contribute to GHG emissions reduction, for example, the use of low-carbon fuels, new and improved vehicle technologies, …

Yttria Rich Tbcs As Candidates For Cmas Resistant Top Coats, Juan Jose Gomez

Open Access Theses & Dissertations

State of the art thermal barrier coatings (TBC) commonly made of 7-8 wt. % yttria stabilized zirconia (7YSZ) are used in modern gas turbines to generate a thermal protection to the underlying super alloy components. TBCs allow higher operating temperatures for hot gas path components, thus, generating higher engine efficiency. The infiltration of molten glassy mineral deposits composed of CaO-MgO-Al2O3-SiO2 (CMAS) represents one of the major threats in reducing performance and service life in aero and land based gas turbine engines. The CMAS deposits are ingested into the engine carried commonly in sand, runways debris, fly ash and volcanic ash. …

Synthesis, Device Fabrication, And Characterization Of Two-Dimensional Molybdenum Disulfide, Gustavo Alberto Lara Saenz

Open Access Theses & Dissertations

The miniaturization of electronic devices according to Moore's Law has been propelled by the continuous demand for faster and smaller devices which continue to advance technology. One recent contribution to this trend was the isolation and characterization of one atom thick of graphite, known as graphene, which led to the Nobel Prize in physics in 2010 being awarded to Andre Geim and Konstantin Novoselov. Graphene and its related nanocarbon derivatives have exceptional mechanical, thermal, optical and electronic properties, making them a potential candidate for electronics and optoelectronics applications. However, this material has no intrinsic bandgap and complicated processes are required …

Improving The Engineering Properties Of Pla For 3d Printing And Beyond, Carmen R. Rocha

Open Access Theses & Dissertations

Additive manufacturing (AM), now more commonly known as 3D printing, has been classified as efficient, fast, and practical in the prototyping sector of product development. In the work presented here, we will use one of the AM techniques known as Material extrusion 3D printing (ME3DP), which has all the advantages of AM. However, one of the biggest challenges facing ME3DP technologies is the limitation of the range of materials used by this technique. Acrylonitrile butadiene styrene (ABS) and poly-lactic acid (PLA) are currently the most common thermoplastics materials used in ME3DP because of their ability to melt and be reprocessed. …

Computational Modeling Of A 60kw Oxy-Methane Direct Power Extraction Combustor, Omar Daniel Vidana

Open Access Theses & Dissertations

ANSYS Fluent was used to optimize components of a direct power extraction combustor. This includes the fuel injector, nozzle, and cooling units. Changes in the injector's inlet location impacted pressure and velocity distribution. An angle of 115 degrees with respect to the x-axis was found to increase distribution efficiency. Temperature and velocity data from the combustor and nozzle were calculated using NASA CEA and Fluent. Magnitudes of temperature and velocity for CEA and Fluent matched within 9% and 4%, respectively. For the cooling system it is expected that cavitation will not occur since the saturation temperature of water is not …

Treatment Of Dissolved Metals For Direct Potable Reuse, Cesar Alberto Alvarez

Open Access Theses & Dissertations

In the process of direct potable reuse (DPR), the bulk of the removal of dissolved metals removal is accomplished by reverse osmosis. This treatment is especially important in wastewater containing contaminants from industrial processes. The goal of this research was to evaluate the performance of DPR with respect to the removal of salinity and dissolved metals to meet drinking standards. Samples were collected from the El Paso Water Utilities Advanced Water Purification pilot system throughout various points in the treatment process. The samples were analyzed for their concentration of ions with Ion Chromatography (IC) and dissolved metals using an Inductively …

Characterization Of High Intensity Turbulent Flows Through Time Resolved Particle Image Velocimetry In A Backward Facing Step Combustor, Martin De La Torre

Open Access Theses & Dissertations

The fundamental understanding of turbulent premixed combustion has taken place as one of the major research topics of interest in industry thanks to advancements in kHz level laser diagnostics such as in Particle Image Velocimetry (PIV) and Planar Laser Induced Fluorescence (PLIF). Because of said advancements in this technology researchers and the scientific community are now able to expand their understanding of flame studies at high turbulence conditions to acquire a better understanding, and improve models used in turbine design, scram/ram jets, rocket engines, and emissions control. This surge of new technologies has made this topic a high priority one …

Damage Tolerance And Assessment Of Unidirectional Carbon Fiber Composites, Mark David Flores

Open Access Theses & Dissertations

Composites are beginning to be used in a variety of different applications throughout industry. However, certification and damage tolerance is a growing concern in many aerospace and marine applications. Although compression-after-impact have been studied thoroughly, determining a damage tolerance methodology that accurately characterizes the failure of composites has not been established. An experimental investigation was performed to study the effect of stacking sequence, low-velocity impact response, and residual strength due to compression and fatigue. Digital Image Correlation (DIC) captured the strains and deformation of the plate due to compression. Computational investigations integrated non-destructive techniques (C-Scan, X-Ray) to determine the extent …

Combining Interval And Probabilistic Uncertainty In Engineering Applications, Andrew Martin Pownuk

Open Access Theses & Dissertations

In many practical application, we process measurement results and expert estimates. Measurements and expert estimates are never absolutely accurate, their result are slightly different from the actual (unknown) values of the corresponding quantities. It is therefore desirable to analyze how this measurement and estimation inaccuracy affects the results of data processing. There exist numerous methods for estimating the accuracy of the results of data processing under different models of measurement and estimation inaccuracies: probabilistic, interval, and fuzzy. To be useful in engineering applications, these methods should provide accurate estimate for the resulting uncertainty, should not take too much computation time, …

Wettability Of Magnesium Based Alloys, Victor Manuel Ornelas

Open Access Theses & Dissertations

The premise of this project was to determine the wettability behavior of Mg-based alloys using three different liquids. Contact angle measurements were carried out along with utilizing the Zisman method for obtaining values for the critical surface tension. Adhesion energy values were also found through the use of the Young-Dupre equation. This project utilized the Mg-based alloy Mg-2Zn-2Gd with supplemented α-Minimum Essential Medium (MEM), Phosphate Buffer Saline solution (PBS), and distilled water. These three liquids are commonly used in cell cultivation and protein adsorption studies. Supplemented α-MEM consisted of α-MEM, fetal bovine serum, and penicillin-streptomycin. Mg-2Zn-2Gd was used because of …