Engineering Commons^™

Structural And Optical Investigations Of Rbxcs1-Xh2po4, Alex D. Price

Open Access Theses & Dissertations

Proton conductor solid acid electrolytes RbxCs1-xH2PO4 (0≤x≤1) have been investigated using second harmonic generation and powder x-ray diffraction. Second harmonic generation is an optical technique which can be used to study the structural properties of materials. Microscopes of this nature have the ability to image objects with a variable penetration depth in a non-destructive manner, allowing for great potential to be used for in situ observations of the electrolyte’s structure when in a fuel cell under operating conditions.

X-ray powder diffraction was carried out on the series of samples and found for values of 0≤x≤0.5 the structure of the material …

Testing Of A 1n Af-M315e Thruster, Daniela Ivette Aguilar

Open Access Theses & Dissertations

The Center for Space Exploration and Technology Research (cSETR) at the University of Texas at El Paso (UTEP) is currently pursuing various space propulsion and small satellite projects. One of these projects is called Orbital Factory X (OFX), which mission is to design a 2U Cube-Satellite (Cube Sat) with 4 green mono-propellant thrusters along with multiple micro-cathode arc thrusters. A CubeSat is a small-scale version of a satellite that is usually placed in orbit for near earth missions. However, they have a relative short life and limited maneuverability due to their limited source of power and restricted payload. Now, technologies …

Geospatial Relationship Of Intelligent Compaction Measurement Values With In-Situ Testing For Quality Assessment Of Geomaterials, Luis Alberto Lemus

Open Access Theses & Dissertations

The implementation of Intelligent Compaction (IC) in the construction of transportation infrastructure as a tool for quality control of compacted geomaterials has attracted the attention of a number of highway agencies. Compaction quality has been conventionally assessed using density, and to a less extent, modulus-based spot measurements at selected locations along the roadway section. While spot measurements do not provide a thorough rendition of the level of compaction of the roadway, IC technology is effective in meeting full coverage requirements. IC roller measurements are accelerometer-based measurements recording machine-ground interaction assumed to be indicative of the stiffness of the compacted geomaterial. …

Magnetotelluric Analysis Of Central Kenya Kenyan Rift Volcanoes For Geothermal Development, Anna Wairimu Mwangi

Open Access Theses & Dissertations

Abstract

High temperature geothermal resources are vast along rift margins because of emplacement of magma in shallow crust. This is the case along the Kenyan Rift valley also known as the Gregory Rift. It is the Eastern arm of the East African rift and a chain of volcanoes along the rift graben characterizes it. We use (MT) magnetotelluric method to image beneath the peralkaline province of the Kenya Rift i.e. Olkaria, Eburru, Badlands, and Longonot volcanoes. The resistivity structure shows active geothermal activity happening at the upper 3km from the subsurface as evidenced by low resistivity cap rock comprised of …

High Recovery Inland Desalination: A Technical And Economic Performance Evaluation Of Zero Discharge Desalination And Other Technologies, Malynda Aragon Cappelle

Open Access Theses & Dissertations

Increasing population and diminishing freshwater resources are leading to increased competition between users of freshwater, both in terms of surface water and groundwater. Desalination can augment the water supply, but conventional approaches like reverse osmosis are usually limited to 70-80% recovery. Inland brine disposal options are often limited, presenting significant technical and economic obstacles to implementing desalination technology. In comparison to conventional desalination technologies, high recovery desalination methods such as Zero Discharge Desalination (ZDD) offer substantially higher potable water yield (i.e., 95-98%) from brackish water. ZDD is a hybrid process that combines reverse osmosis (RO) or nanofiltration (NF) with electrodialysis …

Photo-Induced Charge Transport In Graphene And Semiconducting Wse2 Integrated With Zero-Dimensional Materials For Enhancing Optoelectronic Device Characteristics, Srishti Chugh

Open Access Theses & Dissertations

Two-dimensional (2D) materials encompass a diverse array of properties from the metallic-like character of graphene to the semiconducting nature of many of the transition metal dichalcogenides (TMDCs) such as tungsten diselenide (WSe2). These materials exhibit intriguing interactions with incoming radiation which makes them interesting for electronics and optoelectronics, especially given the high electron mobility and the ballistic nature of the electronic transport under certain conditions. In particular, the semiconducting TMDCs, such as WSe2, express an indirect-to-direct optical transition with scaling from the bulk to monolayers. Despite the enhanced optical absorption characteristics of monolayer WSe2 stemming from its direct band gap, …

An Adaptive Creep Modeling Approach Using Metamodeling, Mohammad Shafinul Haque

Open Access Theses & Dissertations

Recent drives to increase the efficiency of existing fossil energy power plants and the development of Advanced Ultrasupercritical power plants, have led to designs with steam pressures above 4000 psi and temperatures exceeding 1400°F. The complexity of the applied thermo-mechano chemical boundary conditions makes it critically important to consider creep and creep related failures. A primary concern to FE practitioners is the determination of which constitutive models are the "best", capable of reproducing the mechanisms expected in an intended design accurately; as well as what experimental data sets are proper or "best" to use for fitting the constitutive parameters needed …

Effects Of Air And Other Gases In The Stabilization Process Of The Superprotonic Phase Of Cesium Dihydrogen Phosphate Within A Hermetically Sealed Chamber, Israel Martinez

Open Access Theses & Dissertations

The solid acid CsH2PO4 (CDP), exhibits a sudden increase in its proton conductivity as it’s heated above a certain temperature (around T~235oC), which makes it a very attractive candidate to be used as an electrolyte in intermediate temperature fuel cells. Unfortunately, at these temperatures the sample is not stable, as starts to dehydrate; which causes a dramatic drop in the proton conductivity over a short period of time (less than one hour). In order to inhibit, or at least delay, the dehydration process, the solid acid it’s put under a saturated water vapor atmosphere. Another method to stabilize the highly …

Economic And Environmentally Efficient Energy Management System For Optimal Microgrid Operation, Olayinka Samuel Obafemi

Open Access Theses & Dissertations

The aim of this Thesis is to study and understand the economic analysis of integrating renewable energy resources for the purpose of improving the system grid, identifying and monetizing benefits and cost. This Thesis discusses the approach taken and solution created to tackle the current problems facing the production and consumption of electricity and how the microgrid has become a platform for improvement in power system operation. A microgrid in islanded and connected mode are simulated using Homer Pro for optimization and its results help gain an insight into analyzing and monetizing cost and benefits with one common goal in …

A Comparative Study Characterizing Traffic Related Air Pollutant Concentrations At Near-Road Communities In El Paso, Texas, Adan Rangel

Open Access Theses & Dissertations

Numerous scientific studies have demonstrated the influence of traffic related air pollution at near-road communities and the associated health risks for these populations. This study uses on-site air quality monitors to characterize air pollutants at near-road schools in El Paso, TX to understand children's exposure to traffic-related air pollutants. Ambient air monitoring stations were installed at Coldwell Elementary, Bliss Elementary, and a residential house located in close proximity to major inter-state roadways. In this study, air quality data for PM2.5, PM10, NO2, and O3 was collected over a period of nine weeks in Fall 2018. The spatial and temporal variability …

Development And Characterization Of Novel Materials For The Advancement Of Additive Manufacturing By Material Extrusion 3d Printing, Jose Gilberto Siqueiros

Open Access Theses & Dissertations

The development of additive manufacturing technologies has been under the spotlight from the past decade due to its enormous potential to disrupt current manufacturing processes. Material extrusion 3D printing (ME3DP) is the most common type of additive manufacturing technology as it experienced an exponential growth after the expiration of the fused deposition modeling patent filed in 1989 by Scott Crump. The large interest behind this technology is generated from the capacity to create complex shapes, rapid prototyping, relatively ease of use, low cost, and high accessibility. The gradual evolution of material extrusion 3D printing calls to become a technology ordinarily …

Formulation Of Nanoparticle Systems For Drug Delivery Application In Biomedical Sciences, Victor Alfredo Rodriguez

Open Access Theses & Dissertations

Antibiotic-resistant strains of bacteria may result in serious infections which are difficult to treat. In addition, the poor antibiotic pipeline has also contributed to the crisis. Recently, the complex of furosemide and silver (Ag-FSE) has been reported as a potential antibacterial agent. However, its poor aqueous solubility is limiting its activity as an effective antibacterial agent. The purpose of this study was to encapsulate Ag-FSE into chitosan nanoparticles (CSNPs) and evaluate antibacterial efficacy. Ag-FSE CSNPs were prepared using ionic gelation technique. The particle size, polydispersity index and zeta potential of Ag-FSE CSNPs were determined using dynamic light scattering (DLS) technique. …

Back Calculation Of Intelligent Compaction Data For Mechanical Properties Of Soil System, Afshin Gholamy

Open Access Theses & Dissertations

For national economy, it is very important to have a reliable infrastructure. Because of this, all over the world, new roads are constantly being built and old roads are being maintained and, if necessary, expanded and/or repaired. Building a good quality road is very expensive, it costs several million dollars per kilometer. It is therefore crucial to make sure that the newly built and newly repaired roads are sufficiently stiff - so that they can withstand the predicted volume of traffic for a sufficient number of years. Current methods of estimating the stiffness are time-consuming and labor-consuming. The most accurate …

A New Approach To Multiplanar, Real-Time Simulation Of Physiological Knee Loads And Synthetic Knee Components Augmented By Local Composition Control In Fused Filament Fabrication, Joshua Taylor Green

Open Access Theses & Dissertations

Despite numerous advances in biomedical engineering, few developments in surgical simulation have been made outside of computational models. Cadavers remain the primary media on which surgical research and simulation is conducted. Most attempts to quantify the effects of orthopedic surgical methods fail to achieve statistical significance due to limited quantities of cadaver specimen, large variations among the cadaver population, and a lack of repeatability among measurement techniques. The general purpose of the research covered in this dissertation is to develop repeatable simulation of physiological loads and develop techniques to fabricate a synthetic-based replacement of cadaver specimens. Future work applying this …

Utilization Of Digital Image Correlation Technique In Asphalt Testing, Alejandra Escajeda

Open Access Theses & Dissertations

Over 90% of the roads in the United States are paved with hot mix asphalt (HMA). These asphalt pavements include many mix types, such as permeable friction course (PFC), stone mastic asphalt (SMA) and conventional dense graded mixes. The performance of the HMA is an important factor in pavement design programs used by many departments of transportation. The type of HMA selected not only influences the performance of the pavement structure, but also the pavement's life cycle cost. The performance life of an HMA mix is to be studied further with experimental data in order to contribute and expand on …

Onshore-Offshore Velocity Models North Of The Mendocino Triple Junction In Northern California, Alan Jacquez

Open Access Theses & Dissertations

The Mendocino Triple Junction (MTJ) marks the boundary where the Gorda plate, North American Plate, and Pacific Plate meet, separating the Cascadia subduction zone to the North from transform tectonics of the San Andreas plate boundary. This actively deforming region experiences high seismic activity and young geological features. Here we examine offshore and onshore seismic wide-angle reflection and refraction data north of the MTJ crossing the Cascadia subduction zone from offshore northern California to the Western edge of the Sierra Nevada. We image subsurface structures in this region by creating P-wave velocity models using datasets collected in 1993 to 1994 …

Implementing Large Eddy Simulation To Numerical Simulation Of Optical Wave Propagation, Diego Alberto Lozano Jimenez

Open Access Theses & Dissertations

In this study, we want to simulate long-range laser propagation in atmospheric turbulence. The numerical simulations are carried out to study the impact of strong atmospheric turbulence in spatial, temporal, and related spectral domains. The first section of this study will be concerned with modeling this numerical simulation in Kolmogorov and non-Kolmogorov spectrum. To validate our numerical simulation, we will compare the statistical parameter to theoretical approximation in both Kolmogorov and non-Kolmogorov spectrums. Once the code is validated, we want to integrate Large Eddy Simulation (LES) turbulence modeling. LES simulations allowa us to study strong fluid turbulence and can predict …

Titanium Incorporated Gallium Oxide (Ga-Ti-O): Structure Property Relationship And Performance Evaluation For Extreme Environment Applications, Sandeep Manandhar

Open Access Theses & Dissertations

The existing power generation systems, which utilize fossil fuels, are in dire need of efficient, reliable chemical sensors that can operate safely at higher temperatures. These sensors control the combustion environment and the emissions during combustion. Several sensing materials such as SnO2, ZnO, TiO2, WO3, and Ga2O3 exhibit high sensitivity to certain type of chemical molecules and in a certain range of temperatures. Among these candidate materials, β-Ga2O3 is stable at very high temperatures and has shown functionality for oxygen sensing at higher temperatures (>700°C). However, the response time and sensitivity must be significantly improved in order to derive …

Design Of Robotic Tram Unit For Field Data Collection, Quetzalcoatl Mendoza Rosas

Open Access Theses & Dissertations

Satellite remote sensing is the most applied method for detection and measurement of electromagnetic energy and its interaction with Earth surface. the analysis of the data acquired can provide important information with uses in areas as like weather forecasting, military intelligence and environmental and resources location. Due to the great distance from where the samples are taken and even with the most sophisticated sensor it is impossible to have an exactly replica of the Earth surface. As a result, scientist analyze imagery where a single pixel can be the representation of a 30 by 30 meters area of land. This …

Development Of A Desktop Material Extrusion 3d Printer With Wire Embedding Capabilities, Jose Francisco Motta

Open Access Theses & Dissertations

Printed circuit boards (PCB) have been widely used as a permanent solution for generating complex circuitries to power electronic devices. Over the years, PCB boards have proved to be reliable when powering electronic devices. However, when fabricating a printed circuit board, one must outsource to fabricate the boards when in prototype phase. Therefore, the risk of intellectual property theft and long lead time is an issue. The objective of this Thesis is to develop a hybrid multi-tool desktop material extrusion 3D printer that allows for easy integration (modularity) of tools to generate multi-functional 3D printed components.

The addition of an …

Evaluation Of Commercial Pervaporation Membranes For Desalination Of Saline And Brackish Waters, Andres F. Sanchez

Open Access Theses & Dissertations

Pervaporation is a solution separation method that occurs by vapor transport through a selective membrane. As the need to provide drinking water to the growing population increases, pervaporation has potential merit as an alternative desalination technology, especially for water with very high salinity.

To our knowledge, there are no commercially available pervaporation membranes made specifically for desalination applications. Thus, the membranes PERVAP 4100 and PERVAP 4101 manufactured by DeltaMemAG were tested to evaluate their performance in desalination. Because the driving force in pervaporation is the difference in vapor pressure between the feed side and the permeate side of the membrane, …

Data-Driven Predictive Framework For Modeling Complex Multi-Physics Engineering Applications, Arturo Schiaffino Bustamante

Open Access Theses & Dissertations

Computational models are often encountered in multiple engineering application, such as structural design, material science, heat transfer and fluid dynamics. These simulations offer the engineers the capability of understanding complex physical situations before putting them to practice, either through experimentation or prototyping. The current advances in computational sciences, hardware architecture, software development and big data technology, have allowed the construction of sturdy predicting frameworks for analyzing a wide array of natural phenomena across different disciplines, either through the implementation of statistical methods, such as big data, and uncertainty quantification, or through high performance computing of a numerical model. The objective …

An Efficient Method For Online Identification Of Steady State For Multivariate System, Honglun None Xu

Open Access Theses & Dissertations

Most of the existing steady state detection approaches are designed for univariate signals. For multivariate signals, the univariate approach is often applied to each process variable and the system is claimed to be steady once all signals are steady, which is computationally inefficient and also not accurate. The article proposes an efficient online method for multivariate steady state detection. It estimates the covariance matrices using two different approaches, namely, the mean-squared-deviation and mean-squared-successive-difference. To avoid the usage of a moving window, the process means and the two covariance matrices are calculated recursively through exponentially weighted moving average. A likelihood ratio …

Detecting Contaminated Fiber Connectors Using Sfp Optical Power Data, Christopher A. Mendoza

Open Access Theses & Dissertations

Fiber optic technology is an important part of communication networks enabling high-bandwidth transmissions over long and short distances. They do have their fair share of problems though, contamination being the biggest culprit. Contamination of fiber optic connectors can lead to serious performance degradation or even loss of signal. Detecting contaminated fiber connectors can take weeks or even months using traditional practices. There are standard cleanliness practices when dealing with optical connectors but still the problem seems to persist. This work presents an inequality to solve the detection portion of this problem. The proposed inequality uses power readings from the Small …

Hybrid 3d Printing Demonstrated By Arbitrary 3d Meandering Transmission Lines, Ubaldo Robles

Open Access Theses & Dissertations

This Dissertation focuses on the automation of multi-material direct write three-dimensional (3D) manufacturing of arbitrary metal-dielectric structures. The technology was demonstrated by manufacturing 3D meandering interconnects and transmission lines (TLs). Manufacturing 3D functional electronics with multiple materials required pushing the current state of 3D printing (3DP) technology to utilize simultaneous multi-material processes combined with sophisticated slicing and bonding under one process. Multi material 3DP is known as hybrid 3DP. This research pioneered the process for producing meandering transmission lines, starting with design and manufacturing, using hybrid 3DP through micro-dispensing and fuse deposition modeling. The research starts by 3DP magnetic and …

Experimental Laser Powder Bed Fusion System For Difficult To Process Metallic Materials, Syed Zia Uddin

Open Access Theses & Dissertations

The focus of this research was twofold, such as development of defect free fabrication parameters for laser powder bed fusion (LPBF) processing of crack prone or difficult to process metallic materials, and study of the temperature dependence of emissivity for some commonly used metal alloy powders in LPBF process. The later objective extends to the implementation of multiwavelength (MW) pyrometer technology for in situ true surface temperature measurement in LPBF process. LPBF is an additive manufacturing (AM) process capable of layer-by-layer manufacturing by successive laser melting of each layer according to CAD data. AM manufacturing has the inherent advantages of …

Application Of The Positive Deviance Method Within The Field Of Product Design, Cesar Esteban Venegas

Open Access Theses & Dissertations

Positive Deviance (PD) is a method for social innovation that identifies and utilizes the knowledge found from statistical outliers within at-risk communities who succeed against all the odds, despite not having access to any additional resources. The PD method draws striking similarities to a product design methodology know as Human-Centered Design in which they share very similar principals. Similarities include the importance each method places on identifying the correct problem to address. Since it is not clear, from prior research, if the PD method is useful in the field of product development, this research seeks to explore this possibility. The …

Technical Project Management: Union Of Systems Engineering Processes With Project Management Processes, Deyaaldeen M. Abusal

Open Access Theses & Dissertations

Today, most projects in technical fields utilize project management to complete projects as planned, and some of the projects utilize system engineering to cover the project in both technically and commercially. This Thesis investigates the relationship between Project Management (PM) and Systems Engineering (SE) to determine if a suitably professional level of management and level of quality can be achieved. When studying PM and SE separately and make a comparison between both, there is much overlap between these two mature fields. The project could be planned and completed solely by either process. This study combines both fields of Project Management …

Assessment Of Climate Change Impact On Hydraulic Design Procedures Of Bridges, Anjuman Ara Akhter

Open Access Theses & Dissertations

The significant change in climate is evident from the records of increased temperature, changed precipitation pattern, increased frequency of extreme weather events like storms, floods, and so forth. Like other infrastructure highway infrastructures also suffer the consequences of these climate change. Since the hydraulic design of these infrastructures is performed using historical climate data, the designs may not be able to provide services because designs are not considering climate change influence especially in terms of precipitation intensity. This study aims at identifying the most accurate source of climate database that predicts future climate change with less uncertainty and links them …

Evaluation Of Recycled Gypsum Application Dosages To Enhance The Water Infiltration Rate At Water Retention Ponds, Jorge Luis Navarrete

Open Access Theses & Dissertations

The retention ponds play central role for efficient collection, removal, and drainage of rainfall runoff from surrounding streets to minimize flooding and damage. However, low percolating retention ponds may result in an extended ponding of water, abundance bacteria accumulations, mosquito breeding, environmental hazards, among others. The presence of clayey soils and soil sodicity reduces infiltration rates of retention ponds. To enhance the infiltration rate of ponds, it is proposed to use recycled gypsum (RG), as a soil amendment in retention ponds consisting of clayey soils to enhance low infiltration rates.

To evaluate the influence of RG in clayey soils as …