Engineering Commons^™

Characterization Of Wideband U-Slot Patch Antennas Through Characteristic Modal Analysis And Coupled Mode Theory, Tyler Lapointe

Electrical and Computer Engineering ETDs

Microstrip patch antennas (MPAs) are utilized in many applications as they are easy to produce and are thin, versatile, light weight, cheap, and reliable. One of the drawbacks of MPAs, however, is their narrow bandwidth, typically three to ten percent. Fortunately, a perturbation exists capable of resolving this issue known as the U-slot which can increase the operational bandwidth of a single layer MPA to around 30 percent. Often it is reported that the wideband performance of this structure results from the existence of two resonators, the patch and the U-shaped slot. While this is true, the very nature of …

Optimization Of Supersingular Isogeny Cryptography For Deeply Embedded Systems, Jeffrey Denton Calhoun

Electrical and Computer Engineering ETDs

Public-key cryptography in use today can be broken by a quantum computer with sufficient resources. Microsoft Research has published an open-source library of quantum-secure supersingular isogeny (SI) algorithms including Diffie-Hellman key agreement and key encapsulation in portable C and optimized x86 and x64 implementations. For our research, we modified this library to target a deeply-embedded processor with instruction set extensions and a finite-field coprocessor originally designed to accelerate traditional elliptic curve cryptography (ECC). We observed a 6.3-7.5x improvement over a portable C implementation using instruction set extensions and a further 6.0-6.1x improvement with the addition of the coprocessor. Modification of …

Density And Velocity Measurement Of Ari And Arii Using Laser Induced Fluorescence (Lif) In A Large-Scale Helicon Plasma, Ralph F. Kelly

Electrical and Computer Engineering ETDs

Helicon plasma sources are widely used in basic plasma science, as well as for materials processing. These plasmas typically operate at high gas fill pressure, and therefore have significant densities of neutral particles. However, the role of neutrals in the overall plasma dynamics, such as ion flows, remains poorly understood. There are at least two possible mechanisms for neutrals to influence ion flows. One is an FxB drift, where F is the force exerted on ions by neutrals through collisions. The second is through Pedersen conductivity which is dependent on the ratio of the ion cyclotron frequency, ω …

Split-Ring Resonator Waveguide Structure Characterization By Simulations, Measurements And Linear Time-Invariant Modeling, Mohamed Aziz Hmaidi

Electrical and Computer Engineering ETDs

Interest in Metamaterials has been rising drastically in the recent years as they have been used in several optical and RF applications, from antennas to perfect lenses and pulsed power devices. Nevertheless, the time-behavior of metamaterials remains opaque and poorly understood.

In this research work, characterization of a metamaterial structure in time and frequency-domain was made through simulations and experiments. The structure consists in a series of edge-side coupled Split Ring Resonators (SRRs) in a below cutoff waveguide. A linear time invariant model of distributed elements has been elaborated as well in an attempt to approach the structure’s behavior. The …

Growth Of An Algae Polyculture And Dunaliella Tertiolecta In Oilfield Produced Water At A Range Of Salinities And Nutrient Concentrations For Biofuels Production., Thomas C. Hopkins

Civil Engineering ETDs

Growth of algae in saline produced waters (wastewater) from oil and gas production is of interest for potential production of algal biofuels, wastewater treatment and potential reuse or disposal. The objectives of this study were to determine the effects of salt concentrations and nitrogen source (ammonia or nitrate) and concentration on algal growth, lipid production, and nutrient removal to help determine suitability for growth on saline produced waters. Dunaliella tertiolecta (a marine algae) and a polyculture (previously discovered growing in PW) were grown on produced water with a range of salinities and varying nitrogen source and concentration, in a series …

Designing Synthetic Environments To Control Valvular Interstital Cells In Vitro, Kent E. Coombs

Biomedical Sciences ETDs

Aortic valve disease (AVD) is a large contributor to health costs in the United States affecting 2.8% of the population greater than 75 years old. With a growing elderly population due to medical advances, AVD will continue to rise in prevalence over time. Current treatments for AVD are insufficient due to a lack of preventative therapies and the bioprosthetic valves used for surgical replacement have major limitations. Tissue engineered heart valves (TEHVs) present an ideal solution to current AVD needs because of their biocompatibility, capability to integrate with the host’s tissue, and ability to utilize the natural repair mechanisms of …

Experimental Verification Of A6 Magnetron With Permanent Magnet, Andrew J. Sandoval

Electrical and Computer Engineering ETDs

A compact A6 relativistic magnetron with diffraction output using a transparent cathode, simple mode-converter, and a permanent magnet were simulated and tested at the University of New Mexico (UNM) for the Office of Naval Research. The standard compact MDO with a simple mode converter and transparent cathode radiates a TE11 mode axially through a cylindrical horn antenna. The magnetic field, essential for magnetron operation, is provided by a Neodymium Iron Boron (NeFeB) GradeN40M rare earth magnet. The permanent magnet eliminates the need for a pulsed magnet and accompanying circuit, significantly reducing the size of the system. A permanent magnetic field …

Design And Characterization Of Systems For Direct Spatial Imaging Of Low-Energy Gamma-Radiation Sources, Phoenix Baldez

Nuclear Engineering ETDs

This work describes the development of radiation detection systems to identify and image special nuclear material (SNM) using low energy gamma rays. The imaging of these materials is crucial for timely, in the field responses to potential threats to national security. Using a spectroscopy system, the sources can be identified while images can be produced concurrently for the sources which are present. Two systems were designed and characterized in this study, a collimated imager which used collimation in front of a small CdTe detector, and a pixelated pinhole imager, using a pinhole mask in front of a pixelated CZT detector. …

Early Alert Of At-Risk Students: An Ontology-Driven Framework, Elias S. Lopez

Electrical and Computer Engineering ETDs

As higher education continues to adapt to the constantly shifting conditions that society places on institutions, the enigma of student attrition continues to trouble universities. Early alerts for students who are at-risk academically have been introduced as a method for solving student attrition at these institutions. Early alert systems are designed to provide students who are academically at-risk a prompt indication so that they may correct their performance and make progress towards successful semester completion. Many early alert systems have been introduced and implemented at various institutions with varying levels of success. Currently, early alert systems employ different techniques for …

Industry Requirement Gap Analysis For Sustainable Construction Technology, Parya Nickbeen

Civil Engineering ETDs

As sustainable construction becomes a standard necessity in the construction industry, construction engineering and management programs seek to integrate sustainable construction concepts and skills into their degree programs. The aim of this research is to identify industry-required competencies and recognize the possible gaps between industry skills demands and the education provided by academia for sustainable construction technologist jobs. In this study, industry requirements for sustainable construction technologist (mid-level) positions were identified through the analysis of job advertisements, literature review, job analysis (i.e., Developing a Curriculum-DACUM- process), and surveys. Results from the DACUM process provided a categorization of 4 main duties …

Modeling The Interdependencies Of Energy And Water In New Mexico: Historic Drivers, Hydrologic Impacts, And Energy Requirements, Catherine M. Zemlick 5774203

Civil Engineering ETDs

There is increasing need to understand the interdependencies between energy resource development and water resources, particularly in arid regions with vast energy reserves like New Mexico. The state has a long history of energy resource development, including both uranium and fossil fuels. These activities have and continue to impact scarce water resources. There exist gaps in knowledge regarding the drivers of historic uranium mining and the uncertainties inherent in past estimates of groundwater impacts because of mining activity and in current understanding of the energy required to manage water in the oil and gas industry. Although uranium has not been …

Spectro-Electrochemical Platforms For Dynamic Analyses Of Catalytic Cascade Systems, Nalin I. Andersen

Nanoscience and Microsystems ETDs

The development of spectro-electrochemical platforms that facilitate the dynamic analyses of complex catalytic cascade systems was explored in this research. These systems facilitated multiple modalities of catalysts and were used as platforms for monitoring catalytic transformations quasi-in situ. The analytical platforms allowed for the characterization of intermediates and products using surface-enhanced Raman spectroscopy (SERS). The design and fabrication of these devices proved to be reproducible, made of materials that can be manipulated for multiple applications, and incorporate fluid mechanics, electrochemistry, and multimodal catalysis. Microfluidic technology offers capabilities for understanding catalytic cascade systems by providing precise dynamic control of …

An Investigation Of The Effects Of The Second Pyrolysis On The Chemistry, Morphology, And Performance Of Iron-Nicarbazin Catalysts, Elizabeth B. Weiler

Chemical and Biological Engineering ETDs

Proton exchange membrane fuel cells offer a cost-effective, environmentally friendly, and sustainable alternative to petroleum-based power sources to the transportation sector. However, slow electrochemical reactions at the cathode of these fuel cell prevent the technology from being competitive. Iron-nitrogen-carbon based catalysts have emerged as a viable answer to this problem, yet further progress is needed to improve their performance beyond that of current state-of-the-art platinum-based catalysts, which are economically and geopolitically impractical to be a final solution. Currently, a two-step high temperature pyrolysis method has proven a promising way to synthesize iron-nitrogen-carbon catalysts for optimized performance, but there is a …

Experimental Testing Of A Metamaterial Slow Wave Structure For High-Power Microwave Generation, Kevin Aaron Shipman

Electrical and Computer Engineering ETDs

Experimental Testing of a Metamaterial Slow Wave Structure for High-Power Microwave Generation

by

Kevin Aaron Shipman

B.S., Exercise Science, University of New Mexico, 2008

A.S., Mathematics, San Juan College, 2014

M.S., Electrical Engineering, University of New Mexico, 2018

Abstract

A high-power L-band microwave source has been developed using a metamaterial (MTM) to produce a biperiodic double negative slow wave structure (SWS) for interaction with an electron beam. The beam is generated by a ~700 kV, ~6 kA short pulse (~ 10 ns) electron beam accelerator. The design of the metamaterial SWS (MSWS) consists of a cylindrical waveguide, loaded with alternating …

From Flasks To Applications: Design And Optimization Of Giant Quantum Dots Using Traditional And Automated Synthetic Methods, Christina J. Hanson

Nanoscience and Microsystems ETDs

Semiconducting nanocrystals, also known as quantum dots (QDs), that emit light with near-unity quantum yield and are extremely photostable are attractive options as down-conversion and direct electricity-to-light materials for a variety of applications including solid-state lighting, display technologies, bio-imaging and optical tracking. Standard QDs with a core/thin shell structure display fluorescence intermittency (blinking) and photobleaching when exposed to prolonged room temperature excitation for single dot measurements, as well as significant reabsorption and energy transfer when densely packed into polymers or at high solution concentrations.

We have developed thick shell “giant” QDs (gQDs), ultra-stable photon sources both at the ensemble and …

Assessing The Power Of Remotely-Sensed Snow Cover Extent To Improve Understanding Of Snowpack-Streamflow Dynamics: An Application Of Modis Snow Cover In Western U.S. Mountain Watersheds, Jennifer N. Van Osdel

Civil Engineering ETDs

Mountain snowpacks provide essential water for socio-economic systems around the world, with nearly two billion people living in snow sensitive regions. Therefore, methods for characterizing the snowpack-streamflow dynamics at the watershed level are essential for understanding how changes in temperature and precipitation due to climate change will affect the water supply in these regions. However, in-situ snowpack measurements, such as snow water equivalent (SWE), are often unavailable or insufficient due to the financial and logistical constraints of installing snowpack monitoring systems. Remotely-sensed snow cover extent (SCE), or the proportion of a watershed that is covered in snow, has been previously …

Reducing Stress In 3d Printed Parts Made With Laser Engineered Net Shaping, Shaun Ross Whetten

Mechanical Engineering ETDs

Thermal cycling and repeated melting/solidification cycles characteristic of 3D metal printing processes causes buildup of residual stress in 3D printed parts. Using laser engineered net shaping (LENS®), residual stresses are formed leading to deformation and possible cracking of the 3D printed metal components. The LENS process offers opportunities for rapid prototyping, alternative manufacturing processes, and repair of worn/broken components so it is important to be able to minimize the effects of residual stress. Work was performed to understand the benefit of substrate heating on reducing residual stress in metal parts made using the LENS process. Substrate deformation, and destructive methods …

An Analysis Of The Relationship Between Leadership Style And Lean Expressed Through Respect, Proactivity, And Innovative Work Behavior, Reiner Martens

Organization, Information and Learning Sciences ETDs

This dissertation is based on the idea that a leadership style is necessary to implement a lean culture within an organization. This research study employed a systematic literature review, from which a lean leadership model was developed. Based on the two principles of a lean organizational culture, 1. respect for people and 2. continuous improvement, three measurable variables were identified, respect, proactivity, and innovative work behavior. These three variables were connected to the lean leadership model. Leadership styles based on the full range model of leadership were used as independent variable(s). The overarching results of this study were: (1) transformational …

An Exploration Of The Optical Detection Of Ionizing Radiation Utilizing Modern Optics Technology, Sean D. Fournier, Adam Hecht, Cassiano De Oliveira, Jeffrey B. Martin, Richard K. Harrison, Charles Potter

Nuclear Engineering ETDs

Modern ultraviolet (UV) cameras, when combined with UV-transmitting lenses/filter arrangements, can be used to detect radiation dose in air. Ionizing radiation excites nitrogen molecules in ambient air, the resulting decay includes weak emission of ultraviolet photons. Previous work has proven this phenomenon is detectable using highly-sensitive electronically cooled cameras traditionally used in astronomy for low-background imaging. While the ability to detect the presence of radiation (i.e. qualitative measurement) has been demonstrated at Sandia National Laboratories, there are several challenges in correlating images to known dose-fields (quantitative measurement). These challenges include: a low signal to background ratio, interferences due to electronic …

Patient Specific Radiation Doses From Projection Radiography Images: Improving The Accuracy Of Low Dose Radiation Calculations, Daniel J. Sandoval

Nuclear Engineering ETDs

Due to an increase in regulatory scrutiny and medical facility accreditation requirements to monitor patient radiation dose from diagnostic imaging procedures, there is a growing necessity to determine and record accurate patient radiation dose from diagnostic medical imaging procedures. Current methods of patient dosimetry in diagnostic imaging are both extremely difficult and time consuming, require large computing resources (such as Monte Carlo computations), or lack accuracy due to using data based on homogeneous materials and “standard-man sized” anthropomorphic models.

This dissertation provides an algorithm that calculates a more accurate dose using patient-specific projection radiographic images. The algorithm includes measurements acquired …

Fatigue Crack Modeling Of Additively Manufactured Abs Cantilever Beam, Jason W. Booher

Mechanical Engineering ETDs

A Finite Element model was developed to model crack development in additively manufactured additively manufactured Acrylonitrile Butadiene Styrene (ABS) cantilever beams. Experiments were conducted on the beams with both shock and random vibration base excitations. The base excitations induced damage in the beam that cause crack propagation. It was observed during the cracks developmental stages that an increase in damping occurred. The proposed Finite Element model also showed similar increases in damping from the addition of Coulomb damping forces.

Investigation Of Anion And Cation Exchange Membranes For Enhancing Desalination And Power Generation In A Microbial Desalination Cell, Francisco Lopez Moruno

Civil Engineering ETDs

Microbial desalination cell (MDC) is a bioelectrochemical system capable of oxidizing organics, generating electricity and reducing the salinity content into the desalination chamber. In the first part of this study, quaternary ammonium poly(2,6-dimethyl 1,4-phenylene oxide) (QAPPO) anion exchange membranes (AEMs) with topographically patterned surfaces were assessed in a microbial desalination cell (MDC) system. The MDC results with these QAPPO AEMs were benchmarked against a commercially available AEM. The MDC with the non-patterned QAPPO AEM (Q1) displayed the best desalination rate (a reduction of salinity by 53±3 %) and power generation (189±5 mW m^-2) when compared against the commercially …

Experimental Investigation Of And Constitutive Model For The Thermo-Poro-Mechanical Deformation Of Granular Salt Under Hydrostatic Compression, Brandon C. Lampe

Civil Engineering ETDs

The influence of pore pressure and porosity on the ductile deformation of granular salt was experimentally investigated under hydrostatic compression. Confining and pore pressures were independently controlled while granular salt samples exhibited rate-dependent deformation that resulted in large decreases of sample volume and porosity. The sample deformation rates were observed to correspond with both the sample porosity and the pressure difference between the confining and pore pressures. Post-test observations revealed that the reduced porosity was caused by the solid particles deforming in a ductile manner. Insight into the cause of ductile deformation was gained by considering the local stress distribution …

Development Of A Novel Framework For The Application Of Signature Based Safeguards (Sbs) To Pyroprocessing, Philip Leo Lafreniere

Nuclear Engineering ETDs

Traditional nuclear material accountancy (NMA) faces several challenges when applied to pyroprocessing facilities. To address these challenges, alternative methods of safeguarding nuclear material are being developed. One method is process monitoring (PM). PM involves taking operational process data and applying it to safeguards using an advanced framework. Signature Based Safeguards (SBS), a proposed PM framework, involves the identification of anomalous scenarios and the subsequent identification and detection of their respective PM signatures from a system of measurements. SBS has previously focused on failure modes that result in transfer of mass to unexpected places in the mass flowsheet. This work developed …

Physical And Chemical Interactions Affecting U And V Transport From Mine Wastes, Sumant Avasarala

Civil Engineering ETDs

This research investigates the physical and chemical interactions that affect the transport of uranium (U) and vanadium (V) from uranium mine waste sites by integrating laboratory experiments and reactive transport modelling with various spectroscopy, microscopy, and diffraction techniques. The document consists of results from three related studies. In the first study (Chapter 3), the reactive transport of U and V was investigated by sequentially reacting mine wastes collected from Blue Gap/Tachee Claim-28 mine site, AZ with 10mM NaHCO₃ (7.9) and 10mM CH₃COOH (3.4) during continuous flow through column experiments. Under both of these conditions (pH 3.4 and …

Novel Algorithms For Ultra Scale Electromagnetic Problems In The Supercomputing Era, Brian Mackie-Mason

Electrical and Computer Engineering ETDs

The need for increasing fidelity and accuracy in mission-critical electromagnetic applications have pushed the problem sizes toward extreme computational scales. Therefore, there is a large premium placed on the investigation of parallel and scalable integral equation simulators, a particularly useful class of computational electromagnetics, to meet this demand. This dissertation will focus on three interrelated areas: i) quasi-optimal, well-conditioned integral equation based domain decomposition methods, ii) geometry-adaptive, multi-scale discontinuous Galerkin boundary element methods, and iii) high-performance and scalable algorithms to reduce the computational complexity of extreme-scale simulations with the aid of parallel computing architectures. This dissertation will first develop the …

Antennas For Wv Band Applications, Firas Ayoub

Electrical and Computer Engineering ETDs

This dissertation focuses on designing, fabricating and testing antennas that are suitable for operation within the V/W bands. In particular, this work focuses on the design of slotted rectangular waveguide antenna arrays and cross slotted waveguide fed horn antennas. These structures are known for their high efficiency and high circularly polarized gain that can be implemented in satellite and terrestrial communication links. In addition, such designs can be implemented in radar applications that operate infrequency bands around 72 GHz or 84 GHz bands. Such antenna structures are inexpensive to fabricate since they can simply be machined using high precision conventional …

Characterization Of Wellbore Microannuli, Serafin Garcia Fernandez

Civil Engineering ETDs

Wellbore integrity is a principal concern for the safe and efficient underground storage of hydrocarbons, disposal of various wastes and in oil and gas production. Poor wellbore integrity can lead to leakage and loss of extracted or stored material, and the potential for contamination of groundwater. The microannuli, which is the space between the steel casing and the cement sheath has been identified as a common and critical leakage pathway. There are no data of the actual size or character of microannuli; however, it is possible to estimate the hydraulic aperture of the microannulus from flow measurements at the wellhead. …