Engineering Commons^™

Design And Simulation Of Mems Actuators To Study Strain Behavior Of 2d Materials, Mariana Martinez

Open Access Theses & Dissertations

Since the 60s the semiconductor industry has successfully been able to keep pace with Moore's Law due to the effective scaling of the silicon-based transistor. However, as scaling technology improves, passive power density has begun to dominate the overall power consumption of transistors. The inability to scale power density alongside the decreasing transistor dimensions has hindered the efficiency trend observed in the last decades. Thus, new alternatives have been researched to overcome the current power crisis. Micro-electro-mechanical system (MEMS) actuators offer excellent on/off ratios with very steep transitions. Furthermore, two-dimensional transition-metal dichalcogenide (TMD) materials have been studied due to their …

Characterization Of 3d Printed Polylactic Acid/ Polycaprolactone/Titanium Dioxide Composites For Bone Replacement And Grafting, Sandra Elena Najera Beltran

Open Access Theses & Dissertations

A material that mimics the properties of bones was developed by optimizing the ratio of polymer composites of polylactic acid (PLA) and poly-ε-caprolactone (PCL), containing small amounts of titanium oxide (TiO2). Although titanium-based alloys have commonly been used for bone replacement procedures due to their biocompatibility with the human body and their mechanical properties, stress shielding continues to be a problem. The structure of a bone has a porosity which permits the flow of nutrients, blood, oxygen and minerals, and is an issue at the time of creating bone replacements using conventional methods. PLA and PCL have been used in …

The Design Of A Rocket Propulsion Labview Data Acquisition And Control System, Dylan Allan Ott

Open Access Theses & Dissertations

When designing a rocket engine, both the propulsion system and propellant choice(s) are an important deciding factor. Desired rocket engine behavior, specific impulse, and levels of thrust are all different between the various propulsion systems. A bi-propellant cryogenic liquid 5lbf, 500lbf, and 2000lbf rocket engine was designed and manufactured by UTEP. The 5lbf rocket engine is a Reaction Control Engine and the 500lbf and 2000lbf rocket engine is a throttleable Main Engine. To provide a reliable and safe data acquisition and control system for this experiment, a Real-Time control platform was needed. A compact DAQ system was purchased and configured …

Exploring The Effects Of Zinc Nanoparticle Concentration, Antioxidant, And Media On Cilantro (Coriandrum Sativum), And Radish (Raphanus Sativus) Plants Growth, Venkata Laxma Reddy Pullagurala

Open Access Theses & Dissertations

Engineered nanomaterials (ENMs) have proven to be one of the emerging chemicals of concern in the contemporary times. Soil acts as one of the major sinks of these ENMs. Reports have shown that ENMs have varied effects on soil biota. Particularly, their effects on plants are inconsistent. Amongst these ENMs, ZnO nanoparticles (nZnO) are the fourth largest raw materials in the nanotechnology industry. Globally, it is estimated that around 34,000 tons of n ZnO are utilized per year. The nZnO exposure on terrestrial plants yielded both beneficial as well as detrimental effects. Recently, there is an emerging evidence about the …

Solvent And Concentration Effects Governing The Hierarchical Organization Of Asphaltenes: A Small-Angle X-Ray Scattering Study, Hasan Rejoanur Rahman

Open Access Theses & Dissertations

Asphaltenes are a group of planar molecules found in crude oil and are prone to aggregation which often causes blockage of pipes along the oil production stream resulting a huge economic downside. In an effort to understand the hierarchical organization of asphaltene in different solvents and concentrations, the solution structure of various asphaltene solutions were studied using small-angle x-ray scattering (SAXS). Solvents were chosen based on miscibility maps. Such maps are generated on the critical value of the solubility parameter difference between asphaltenes or asphaltene components, and a range of solvents. The critical factors that affect asphaltene and asphaltene component …

Evaluation Of Powdered Activated Carbon For Control Of Taste And Odors Caused By Geosmin, Anthony Joe Rodriguez

Open Access Theses & Dissertations

The primary sources of taste and odor problems associated with surface water supplies spawn from algae and bacterial blooms that secrete odorous chemicals such as Geosmin and MIB. These musty, odorous, organic compounds are usually detectable by the human nose at concentrations of 5 to 10 ppt and can create considerable concern by consumers that can lead to complaints and misconceptions of odors as a water quality problem. Typically, since chemical or ozone treatment can be costly, activated carbon (powdered or granular) is generally employed in the process of removing organic compounds, such as Geosmin and MIB. The research presented …

Superpixel-Based Unsupervised Hyperspectral Unmixing, Jiarui Yi

Open Access Theses & Dissertations

Recently, superpixel-based approaches have been proposed for hyperspectral unmixing. The basic assumption of this approach is that the superpixel over-segmentation segments the image into small homogeneous areas. A low-dimensional (LD) image representation is obtained by using the average of the superpixels, which are then used in other image processing tasks up the processing chain. Due to superpixel-segmentation algorithm limitations, the region inside a superpixel may not be homogeneous. Therefore, the average may not be an adequate representation for the superpixel, leading to inaccuracies in the low dimensional representation resulting in errors in the image processing tasks or analysis. Here we …

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 …

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 …

Constitutive Model Development For Additive Manufacturing, Diana Berenice Montes

Open Access Theses & Dissertations

Additive manufacturing (AM) is known worldwide for revolutionizing the development of three-dimensional modeling by reducing the time and increasing the precision of parts. For Powder Bed Fusion research is necessary to reduce concerns in residual stress, porosity and cracking in AM parts. A constitutive model was created in Abaqus to validate material properties of 3D printed Al 6061. Finite element analysis was performed to investigate how properties may affect in the modification of parameters to reduce printing imperfections. Research was made as well in polylactic acid properties for material extrusion to explore its behavior for creep and relaxation. Properties were …

Evaluation Of Brackish Water Desalination By Membrane Capacitive Deionization Systems: Performance Tradeoffs In Salt Removal, Hydraulic Recovery, Charge Efficiency, And Specific Energy Consumption, Oluwaseye Michael Owoseni

Open Access Theses & Dissertations

As potable water demand continues to exceed availability in several regions of the world, alternative water sources such as desalination and direct potable reuse have become of high importance in water sustainability discussions. The conventional desalination technologies include reverse osmosis (RO) and thermal distillation. Major barriers to the applicability of these technologies for desalination include inorganic scaling (RO) and high energy requirements respectively. This research provides an evaluation for the feasibility of Membrane Capacitive Deionization (MCDI), which is a technology gaining interest due to its theoretically low energy requirements for brackish water (less than 3 g/L) desalination. The motivation for …

Effects Of Unweathered Or Soil Weathered Copper-Based Nanoparticles And Compounds On Soil Grown Bell Pepper (Capsicum Annuum) And Spinach (Spinacia Oleracea) Plants, Swati Rawat

Open Access Theses & Dissertations

Engineered nanoparticles (ENPs) find large scale industrial application because of their promising chemical, physical, electrical, magnetic, optical, and electronic properties. Copper-based ENP are used as gas sensors, in catalysts, electronics, semi-conductors, and in agriculture. They have been useful as agricultural amendments in the form of pesticides, herbicides, and fertilizers because of their antifungal and antibacterial properties. They also find application in electronics and sensors used in precision agriculture. Due to their massive production and use, ENPs are likely to be ubiquitous in the environment around us in the near future. Application of biosolids for fertilization and water from wastewater treatment …

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 …

Influence Of Mix Design Parameters On Performance Of Balanced Asphalt Mixtures, Luiza Helena Barros

Open Access Theses & Dissertations

With the popularity of the Balanced Mix Design (BMD) concept, the need for performance tests that can reliably evaluate the cracking and rutting potentials of asphalt concrete (AC) mixes has become more critical. A great deal of effort has been focused on incorporating test methods that can potentially improve the current AC mix-design processes and consequently screen underperforming AC mixes. However, the influence of mix design parameters on the performanceof BMD mixes that provide pavement engineers and designers with thorough guidelines and a reliable and consistent test protocol has not been extensively documented.

This Thesis presents an experimental evaluation of …

Implementation Of Magnesium Alloy Az91d On Wire And Arc Additive Manufacturing, David Adrian Martinez Holguin

Open Access Theses & Dissertations

As progress on Additive Manufacturing (AM) techniques focusing on ceramics and polymers evolve, metals continue to be a challenging material to manipulate when fabricating products. Current methods, such as Selective Laser Sintering (SLS) and Electron Beam Melting (EBM) face many intrinsic limitations due to the nature of their processes. Material selection, elevated cost and low deposition rates are some of the barriers to consider when one of these methods is to be used for the fabrication of engineering products. The research here presented demonstrates the use of a Wire and Arc Additive Manufacturing (WAAM) system for the creation of metallic …

Optimization For The Allocation Of Funds For Pavement Maintenance In Pavement Management Systems, Armando Ramirez

Open Access Theses & Dissertations

Pavement maintenance and rehabilitation are critical and costly elements for highway agencies. A challenge for transportation agencies is to preserve roadways in an appropriate condition and extend the pavement service life while maintaining the safety and satisfaction of its users, and maximize the benefits obtained by the repair investments. Pavement maintenance programming is increasing in complexity due to limited resources and increments in traffic and population. Management decisions are usually based on personal judgment by pavement managers and sometimes those decisions are not even supported by previous experience. Research shows that optimization methods can produce significant benefits when transportation agencies …

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 …

People Detection From Time-Of-Flight Imagery With Inpainting-Based Preprocessing, Basavarajaiah Totada

Open Access Theses & Dissertations

The Thesis describes a method of detection and tracking of people using depth images captured by a Time-of-Flight (ToF) camera, such as those obtained with a Microsoft Kinect V2. Key advantages of this approach are that the identity of people is not disclosed, and the system can operate in low-light conditions. The automated approach developed here is inspired by cell-tracking methods as implemented in the well-known biomedical imaging software called CellProfiler. Our approach involves significant preprocessing of the depth images by a combination of adaptive center weighted median filtering and iterative inpainting. The next step is detection of each person's …

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 …

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 …

Predictive Modeling On The Piezoelectric Properties Of 3d Printed Functional Nanocomposites Using The Data Analytics Approach, Md Didarul Islam

Open Access Theses & Dissertations

This paper presents research done on prediction modeling using a data analytics approach to determine various factors affecting the piezoelectric properties of the 3D printed pressure sensors. Previously, the material extrusion 3D printing technique was used to fabricate pressure sensors composed of multiwall carbon nanotubes (CNT), barium titanate (BT), and polyvinylidene fluoride (PVDF) using simple fabrication and low-cost methods. This sensor produced a voltage output of 725 mV (0.13 pC/N) which is enough for pressure sensing applications. However, a holistic study to determine impacts of all factors was not carried out in the previous model. In this study, the design …

Analysis Of High Performance Scientific Programming Workflows, Withana Kankanamalage Umayanganie Klaassen

Open Access Theses & Dissertations

Substantial time is spent on building, optimizing and maintaining large-scale software that is run on supercomputers. However, little has been done to utilize overall resources efficiently when it comes to including expensive human resources. The community is beginning to acknowledge that optimizing the hardware performance such as speed and memory bottlenecks contributes less to the overall productivity than does the development lifecycle of high-performance scientific applications. Researchers are beginning to look at overall scientific workflows for high performance computing. Scientific programming productivity is measured by time and effort required to develop, configure, and maintain a simulation experiment and its constituent …

Magnetic And Catalytic Properties Of Transition Metal Doped Mos2 Nanocrystals, Luis Martinez

Open Access Theses & Dissertations

Magnetism and catalytic activity of nanoscale layered two-dimensional (2D) transition metal dichalcogenides (TMDs) have gained an increasing research interest in the recent past. To broaden the current knowledge and understanding on this subject, in this work, together with my collaborators, I study the magnetic and electrocatalytic properties of hydrothermally grown pristine and transition metal doped (10% of Co, Ni, Fe and Mn) 2H-MoS2 nanosheets/nanocrystals (NCs), with the particle size of 25-30 nm. A broad range of experimental measurements such as x-ray diffraction, transmission electron microscopy, x-ray photo absorption spectroscopy, Raman spectroscopy, magnetic, catalytic and electron spin resonance have been employed …

Structural Design Of Thrust Measurement System For Cryogenic Rocket Engines, Abner Jael Moreno Tarango

Open Access Theses & Dissertations

The Center for Space Exploration and Technology Research (cSETR) at The University of Texas at El Paso (UTEP) has been the leader in academia on the development of Liquid Oxygen (LO2) and Liquid Methane (LCH4) propulsion technologies. One of the projects being developed at cSETR is a suborbital vehicle whose mission is to evaluate performance parameters, demonstrate restart capability, and demonstrate the propulsion system operation in microgravity. This vehicle, called Daedalus, will use a 500-lbf LO2-LCH4 rocket engine that can be throttled down to 100-lbf. To accomplish this goal, UTEP partnered with the El Paso County to lease a plot …

Shape Detection Of Structural Electronics Using Machine Vision System Embeded Into Scara Robot, Varaha Venkat Vyas Kumar Naidu

Open Access Theses & Dissertations

Additive manufacturing processes combined with enhanced technologies for electronics production enables a highly flexible manufacturing of personalized 3D electronic devices. Due to the technical progress within the last years, these technologies made their way from prototyping towards manufacturing. The growing request for products manufactured in batch size, making use of a robot to incorporate the electronic components necessary to make functional 3-Dimensional-Structural Electronics will extend the mass production possibilities. There is significant interest in automation of a process in which parameters are influential in the occurrence of assembly defects and which adjustments should be made to those variables to reduce …

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 …

Fracture Mechanics Of Heterogeneous Composites, Md Fazle Rabbi

Open Access Theses & Dissertations

The increasing application of composite materials due to their ubiquitous advance in terms of mechanical and thermal properties has brought attention to the fracture mechanics of the materials possessing heterogeneity. Recent investigations have focused on the micro- and macro-mechanism of fracture in heterogeneous composites (HCs). In this study, the fracture mechanics of the two HCs: Polymer bonded explosive (PBX) simulant and hot mixed asphalt (HMA) are evaluated on the macroscopic scale. It is an interest of Sandia National Laboratory to examine the fracture resistance of PBXs, particularly those of varying composition and subjected to aging. In this research, a batch …

Multi-State Multi-Objective Reliability Analysis Of Renewable Energy Systems, Luis Ramirez

Open Access Theses & Dissertations

This work presents a new multi-objective evolutionary algorithm (MOEA), capable of obtaining a system's reliability while considering other objectives that concurrently need to be optimized. The algorithm is applied in two different case studies. One of the problems considers a multi-state, multi-objective renewable energy system which tries to find a configuration between solar panels and wind turbines that maximizes the system's reliability of achieving specific energy demand, while also minimizes the purchasing cost of the system. The second case study analyzes a flexible manufacturing system that contains different machines that can perform different functions. The primary objective is to obtain …

The Effect Of Data Marshalling On Computation Offloading Decisions, Julio Alberto Reyes Muñoz

Open Access Theses & Dissertations

Computation offloading consists in allowing resource constrained computers, such as smartphones and other mobile devices, to use the network for the remote execution of resource intensive computing tasks in powerful computers. However, deciding whether to offload or not is not a trivial problem, and it depends in several variables related to the environment conditions, the computing devices involved in the process, and the nature of the task to be remotely executed. Furthermore, it comprises the optimal solution to some questions, like how to partition the application and where to execute the tasks.

The computation offloading decision problem has been widely …

Tribological Characterization Of Ti-Based Alloys For Biomedical Applications In Simulated Body Fluid, Edgar Reyes

Open Access Theses & Dissertations

Tribology is a terminology introduced in the 1960's and it is a study that relates to the investigation of the damage of materials. Titanium, as a material used for a wide range of application, it has been brought to the attention of researchers some characteristics such as its much lower density if compared to steel, its capability as an alloying agent with an amount of metals to enhance physical and mechanical properties, to name just a few characteristics. This paper will discuss the performance on tribology behavior in two different Titanium alloys. These Titanium alloys are Ti-6Al-4V (Ti64), and Ti-24Nb-4Zr-8Sn …