Engineering Commons^™

Plume Contamination Measurements Of An Additively-Printed Gox/Abs Hybrid Thruster, David A. Brewer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis examines the impact of the physical contamination on optical surfaces of spacecraft by an ABS/GOX thruster. Plume contamination presents a significant operational hazard for spacecraft solar arrays and thermal control surfaces can lead to decreased power production and increased spacecraft temperatures. Historically, due to the lack of a reliable, on-demand, and multiple-use ignition methodology, hybrid rockets have never been previously considered for in-space propulsion. Recent advancements in hybrid rocket technologies, have made hybrid systems feasible for in space propulsion. However, prior to this study no research had ever been performed with regard to plume contamination effects due to …

Biomass And Phycocyanin From Oil And Natural Gas Extraction Produced Water Utilizing A Cyanobacteria Dominated Rotating Algal Biofilm Reactor (Rabr), Jonathan L. Wood

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The production of cyanobacterial biofilm biomass and phycocyanin from Rotating Algal Biofilm Reactors utilizing undiluted produced water from oil and natural gas extraction as a culture medium was investigated in this study. Produced water is the largest waste stream generated by the oil and natural gas industries and represents a large volume of non-potable water that may be available for algae culture with minimal impact on freshwater resources. Combining the use of produced wastewater as culture medium with the production of high value algal pigments, such as phycocyanin, may increase the economic viability of algae culture and wastewater purification. High …

The Effects Of Geometric And Stoichometric Change In Nanoparticles And Materials On Lattice Thermal Conductivity, W. Tanner Yorgason

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Thermal transport properties are critical for applications ranging from thermal management to energy conversion. Passive thermal management has been an area of study for over a century and has only grown as technology has advanced because it requires no additional energy to remove heat. Changing the nanostructure of the materials involved in passive heat transfer methods, either by geometric changes or stoichiometric changes, can greatly improve the effectiveness of this heat transfer method. In order to explore this further, this work employs LAMMPS molecular dynamics (MD) simulation software to calculate the lattice thermal conductivity (λ_p) of a …

Gps Denied Localization Using Ultra-Wideband Radios, Joshua P. Vanfleet

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

GPS denied environments cause each unmanned ground vehicle (UGV) in an autonomous convoy to lose positional accuracy which can lead to inoperability, or even damage. In order for autonomous convoy systems to fill the needs of any particular field, a well-performing system must be designed such that a convoy can operate in any environment. Ultra-wideband (UWB) radios are a proposed solution to GPS denied localization. The main objective of this research is to use UWB radios to localize a leader vehicle within a convoy situation while in a GPS denied environment.

Ultraviolet Diffraction Assisted Image Correlation (Uv-Daic) For Single-Camera 3d Strain Measurement At Extreme Temperatures, Ethan K. Nickerson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Digital Image Correlation (DIC) is a technique which uses images taken before and after deformation to determine displacement and strain data over the surface of the sample. In order to obtain this data for both in-plane as well as out-of-plane direction, multiple views of the sample are required. Typically, this is accomplished using multiple cameras, but it is possible to use diffraction gratings to bend the light coming from the specimen in order to allow a single camera to capture multiple views. This technique is referred to as Diffraction Assisted Image Correlation (DAIC) and has been previously demonstrated at room …

On Thermal Bowing Of Concrete Sandwich Wall Panels With Flexible Shear Connectors, Fray Pozo

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Thermal bowing, often referred as bulging or out-of-plane wall deflection, is a common issue on sandwich panel walls caused by a temperature differential between a building interior temperature and the environment. The stresses caused by temperature changes in concrete members are widely known in the practice of bridge design, but not on sandwich wall panels. For sandwich wall panel applications, it is common to have non-composite panels when the designer expects a high temperature gradient, what yields a less economical design, but reduces the bowing.

This project aimed to validate current assumptions regarding the heat flow in sandwich wall panels …

Split Latency Allocator: Process Variation-Aware Register Access Latency Boost In A Near-Threshold Graphics Processing Unit, Asmita Pal

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Over the last decade, Graphics Processing Units (GPUs) have been used extensively in gaming consoles, mobile phones, workstations and data centers, as they have exhibited immense performance improvement over CPUs, in graphics intensive applications. Due to their highly parallel architecture, general purpose GPUs (GPGPUs) have gained the foreground in applications where large data blocks can be processed in parallel. However, the performance improvement is constrained by a large power consumption. Likewise, Near Threshold Computing (NTC) has emerged as an energy-efficient design paradigm. Hence, operating GPUs at NTC seems like a plausible solution to counteract the high energy consumption. This work …

Design And Control Of Series Resonant Converters For Dc Current Power Distribution Applications, Hongjie Wang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

With the growth of renewable energy usage and energy storage adoption in recent decades, people have started to reevaluate the possible roles of dc systems in current and future electrical systems. The dc voltage distribution has been applied in various applications, such as data centers and aircraft industry, for high efficiency and power density. However, for some applications such as subsea gas and oil fields, and ocean observatory systems, the dc current distribution is preferred over dc voltage distribution for its low cost and robustness against cable faults. Design and control of dc power distribution systems for different applications is …

An Experimental Comparison Of Student Motivation Between Two Computational Thinking-Based Stem Activities: Vex-Based Automation And Robotics And A Quadcopter Activity, Cory J. Ortiz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to compare student motivation between two junior high level computational thinking based STEM curricular activities. These two activities were a newly developed quadcopter based curriculum and a VEX based curricular activity developed for Project Lead the Way’s Gateway to Technology – Automation and Robotics course. Student motivation was assessed using an assessment called My Class Activities which broke motivation into four constructs: interest, challenge, choice, and enjoyment.

This study assessed students in three schools in a northern Utah school district. Students were assessed after receiving each curriculum. Assessment responses were then coded and analyzed. …

A Comparison Of The Effects Of Enhanced Hands-On Intervention Versus Textbook Interventions To Understand Student Misconceptions In Particle Dynamics, Gang Liu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The present dissertation research examined the effects of applying the enhanced hands-on intervention to reveal and correct student misunderstandings of the concepts in engineering dynamics, especially particle dynamics. We involved 36 student volunteers for three different research topics. The student participants were divided into two groups in each research topic: enhanced hands-on intervention and pure textbook groups. An interview and intervention was conducted with each participant individually.

The author introduced the “Think-Aloud” method with two kinds of interventions mentioned above. The participants were required to speak out their thought process loud as they worked on the two sets of assessment …

Quantifying Dominant Heat Fluxes In An Arctic Alaskan River With Mechanistic River Temperature Modeling, Tyler V. King

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Temperatures strongly affect physical, chemical, and biological processes in rivers and streams. The processes that influence river temperatures are known across most geographic regions, but the relative importance varies significantly. Little is known about what controls water temperature Arctic rivers, limiting our ability to understand the impacts of climate change. This dissertation addresses this knowledge gap by incorporating field measurements with river temperature modeling to estimate the relative importance of key factors that affect Arctic river temperatures. Results indicate that shortwave radiation (e.g., sunlight) and net longwave radiation are significant throughout an Arctic watershed in all flow conditions. In areas …

Development And Optimization Of A Produced Water, Biofilm Based Microalgae Cultivation System For Biocrude Conversion With Hydrothermal Liquefaction, Benjamin L. Peterson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Extraction of oil and gas in Utah’s Uintah Basin results in large quantities of wastewater, or produced water, with nutrients and residual organic chemical that represent a significant resource for producing energy-related and value-added products. Produced water was obtained as a biomass producing nutrient source from industries operating in Utah’s Uintah Basin. Within the Uintah Basin (defined as Uintah and Duchesne Counties within Utah) approximately 93 million barrels of water were produced in 2013 while only 11% of the water was disposed of through evaporation, with the national average at 2%. The rest is reinjected into the subsurface.

The goal …

Efficient Algorithms For Reconfigurable Antenna Systems, Mehedi Hasan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The main goal of this research is to develop algorithms to facilitate the use of a new type of antenna, called multifunctional reconfigurable antenna (MRA). Traditional antennas have fixed radiation properties which cannot be changed to adapt to different environments. To solve this problem, MRAs, which can dynamically change its operation frequency, radiation patter, and polarization, has gained a significant interest recently. Such antennas can support multiple radio access technologies with different sets of operational requirements. Reconfigurable antennas are considered smart antennas. The efficient use of smart antennas requires efficient and smart underlying algorithms. This dissertation focuses on developing efficient …

Novel Methods To Produce Large Recombinant Spider Silk Proteins Via Polymerization, Nathan L. Hebert

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Spider silk has long been a subject of scientific research due to its remarkable mechanical properties. Until recently, there has been no way to effectively obtain spider silk except by harvesting it from individual spiders. With advances in technology, the genes that code for the individual spider silk proteins have been isolated and genetically engineered into other hosts to produce recombinant spider silk proteins (rSSp) of varying sizes, Larger rSSp have correspondingly greater mechanical properties in any resulting materials. Using current production methods, larger rSSp cannot be produced in commercially viable quantities while simultaneously being economically viable. The current production …

Development And Characterization Of Aqueous-Based Recombinant Spider Silk Protein Biomaterials With Investigations Into Potential Applications, Thomas I. Harris

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Spider silks are incredible natural materials that possess desirable combinations of strength, elasticity, weight, and robustness. Other properties such as biocompatibility and biodegradability further increase the worth of these materials. The possibility of farming spiders is impractical due to spiders’ natural behaviors. Modern biotechnologies have allowed for recombinant spider silk proteins (rSSps) to be produced without the use of spiders. However, the features responsible for spider silks impressive properties can cause difficulties with producing silk materials. A recently developed water-based and biomimetic solvation method has provided a solution to such difficulties and has also led to novel silk biomaterials. Most …

Uncertainty Quantification And Sensitivity Analysis Of Multiphysics Environments For Application In Pressurized Water Reactor Design, Cole David Blakely

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The most common design among U.S. nuclear power plants is the pressurized water reactor (PWR). The three primary design disciplines of these plants are system analysis (which includes thermal hydraulics), neutronics, and fuel performance. The nuclear industry has developed a variety of codes over the course of forty years, each with an emphasis within a specific discipline. Perhaps the greatest difficulty in mathematically modeling a nuclear reactor, is choosing which specific phenomena need to be modeled, and to what detail.

A multiphysics computational environment provides a means of advancing simulations of nuclear plants. Put simply, users are able to combine …

Apple Flower Detection Using Deep Convolutional Networks, Philipe A. Dias, Amy Tabb, Henry P. Medeiros

Electrical and Computer Engineering Faculty Research and Publications

To optimize fruit production, a portion of the flowers and fruitlets of apple trees must be removed early in the growing season. The proportion to be removed is determined by the bloom intensity, i.e., the number of flowers present in the orchard. Several automated computer vision systems have been proposed to estimate bloom intensity, but their overall performance is still far from satisfactory even in relatively controlled environments. With the goal of devising a technique for flower identification which is robust to clutter and to changes in illumination, this paper presents a method in which a pre-trained convolutional neural network …

Towards A Smart World: Hazard Levels For Monitoring Of Autonomous Vehicles’ Swarms, Francesca M. Favaro, Shivangi Agarwal, Nazanin Nader, Sumaid Mahmood

Mineta Transportation Institute

This work explores the creation of quantifiable indices to monitor the safe operations and movement of families of autonomous vehicles (AV) in restricted highway-like environments. Specifically, this work will explore the creation of ad-hoc rules for monitoring lateral and longitudinal movement of multiple AVs based on behavior that mimics swarm and flock movement (or particle swarm motion). This exploratory work is sponsored by the Emerging Leader Seed grant program of the Mineta Transportation Institute and aims at investigating feasibility of adaptation of particle swarm motion to control families of autonomous vehicles. Specifically, it explores how particle swarm approaches can be …

Exact Processing Of Uncertain Top-K Queries In Multi-Criteria Settings, Kyriakos Mouratidis, Bo Tang

Research Collection School Of Computing and Information Systems

Traditional rank-aware processing assumes a dataset that contains available options to cover a specific need (e.g., restaurants, hotels, etc) and users who browse that dataset via top-k queries with linear scoring functions, i.e., by ranking the options according to the weighted sum of their attributes, for a set of given weights. In practice, however, user preferences (weights) may only be estimated with bounded accuracy, or may be inherently uncertain due to the inability of a human user to specify exact weight values with absolute accuracy. Motivated by this, we introduce the uncertain top-k query (UTK). Given uncertain preferences, that is, …

Iterated Local Search Algorithm For The Capacitated Team Orienteering Problem, Aldy Gunawan, Kien Ming Ng, Vincent F. Yu, Gordy Adiprasetyo, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

This paper focuses on a recent variant of the Orienteering Problem (OP), namely the Capacitated Team Orienteering Problem (CTOP). In this problem, each node is associated with a demand that needs to be satisfied and a score that need to be collected. Given a set of homogeneous fleet of vehicles, the main objective is to find a path for each available vehicle in order to maximize the total score, without violating the capacity and time budget of each vehicle. We propose an Iterated Local Search algorithm that has been applied in solving various variants of the OP. We propose two …

Learning Representations Of Ultrahigh-Dimensional Data For Random Distance-Based Outlier Detection, Guansong Pang, Longbing Cao, Ling Chen, Defu Lian, Huan Liu

Research Collection School Of Computing and Information Systems

Learning expressive low-dimensional representations of ultrahigh-dimensional data, e.g., data with thousands/millions of features, has been a major way to enable learning methods to address the curse of dimensionality. However, existing unsupervised representation learning methods mainly focus on preserving the data regularity information and learning the representations independently of subsequent outlier detection methods, which can result in suboptimal and unstable performance of detecting irregularities (i.e., outliers).This paper introduces a ranking model-based framework, called RAMODO, to address this issue. RAMODO unifies representation learning and outlier detection to learn low-dimensional representations that are tailored for a state-of-the-art outlier detection approach - the random …

Experiments Of Propeller-Induced Flow Effects On A Low-Reynolds-Number Wing, Gavin K. Ananda, Robert Deters, Michael S. Selig

Publications

Novel findings are discussed in this paper that will be especially beneficial to designers and modelers of small-scale unmanned air vehicles and high-altitude long-endurance vehicles that both operate at low Reynolds numbers (Re = 50,000-300,000). Propeller-induced Oow effects in both tractor and pusher configurations on a recta ngular wing using the Wortmann FX 63-137 airfoil (a common low-Reynolds-number high-lift airfoil) are presented in this paper . Significant performance benefits can be found for a wing in the tractor configuration. Experiments, including trip tests and upper-surface oil Dow visualization, show and verify that the propeller slipstream induces early transition to turbulent …

Channel Estimation And Ici Cancelation In Vehicular Channels Of Ofdm Wireless Communication Systems, Vahid Vahidi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Orthogonal frequency division multiplexing (OFDM) scheme increases bandwidth efficiency (BE) of data transmission and eliminates inter symbol interference (ISI). As a result, it has been widely used for wideband communication systems that have been developed during the past two decades and it can be a good candidate for the emerging communication systems such as fifth generation (5G) cellular networks with high carrier frequency and communication systems of high speed vehicles such as high speed trains (HSTs) and supersonic unmanned aircraft vehicles (UAVs). However, the employment of OFDM for those upcoming systems is challenging because of high Doppler shifts. High Doppler …

Evaluation Criteria For Selecting Nosql Databases In A Single Box Environment, Ryan D. Engle, Brent T. Langhals, Michael R. Grimaila, Douglas D. Hodson

Faculty Publications

In recent years, NoSQL database systems have become increasingly popular, especially for big data, commercial applications. These systems were designed to overcome the scaling and flexibility limitations plaguing traditional relational database management systems (RDBMSs). Given NoSQL database systems have been typically implemented in large-scale distributed environments serving large numbers of simultaneous users across potentially thousands of geographically separated devices, little consideration has been given to evaluating their value within single-box environments. It is postulated some of the inherent traits of each NoSQL database type may be useful, perhaps even preferable, regardless of scale. Thus, this paper proposes criteria conceived to …

Asic Design Of Rf Energy Harvester Using 0.13um Cmos Technology, Jainish K. Zaveri

Master's Theses

Recent advances in wireless sensor nodes, data acquisition devices, wearable and implantable medical devices have paved way for low power (sub 50uW) devices. These devices generally use small solid state or thin film batteries for power supply which need replacement or need to be removed for charging. RF energy harvesting technology can be used to charge these batteries without the need to remove the battery from the device, thus providing a sustainable power supply. In other cases, a battery can become unnecessary altogether. This enables us to deploy wireless network nodes in places where regular physical access to the nodes …

Iris Biometric Identification Using Artificial Neural Networks, Kevin Joseph Haskett

Master's Theses

A biometric method is a more secure way of personal identification than passwords. This thesis examines the iris as a personal identifier with the use of neural networks as the classifier. A comparison of different feature extraction methods that include the Fourier transform, discrete cosine transform, the eigen analysis method, and the wavelet transform, is performed. The robustness of each method, with respect to distortion and noise, is also studied.

The Development And Validation Of Sinatra: A Three-Dimensional Direct Simulation Monte Carlo (Dsmc) Code Written In Object-Oriented C++ And Performed On Cartesian Grids, David Matthew Galvez

Master's Theses

The field of Computational Fluid Dynamics (CFD) primarily involves the approximation of the Navier-Stokes equations. However, these equations are only valid when the flow is considered continuous such that molecular interactions are abundant and predictable. The Knudsen number, $Kn$, which is defined as the ratio of the flow's mean free path, $\lambda$, to some characteristic length, $L$, quantifies the continuity of any flow, and when this parameter is large enough, alternative methods must be employed to simulate gases. The Direct Simulation Monte Carlo (DSMC) method is one which simulates rarefied gas flows by directly simulating the particles that compose the …

Electrochemical Glucose Sensors Enhanced By Methyl Viologen And Vertically Aligned Carbon Nanotube Channels, Benjamin J. Brownlee, Meisam Bahari, John H. Harb, Jonathan C. Claussen, Brian D. Iverson

Faculty Publications

Free-standing, vertically aligned carbon nanotubes (VACNTs) were patterned into 16 μm diameter microchannel arrays for flow-through electrochemical glucose sensing. Non-enzymatic sensing of glucose was achieved by the chemical reaction of glucose with methyl viologen (MV) at an elevated temperature and pH (0.1 M NaOH), followed by the electrochemical reaction of reduced-MV with the VACNT surface. The MV sensor required no functionalization (including no metal) and was able to produce on average 3.4 electrons per glucose molecule. The current density of the MV sensor was linear with both flow rate and glucose concentration. Challenges with interference chemicals were mitigated by operating …

Impact Of Extended Sintering Times On Mechanical Properties In Pa-12 Parts Produced By Powderbed Fusion Processes, Garrett Craft, Justin Nussbaum, Nathan B. Crane, J. P. Harmon

Faculty Publications

Additive Manufacturing provides many advantages in reduced lead times and increased geometric freedom compared to traditional manufacturing methods, but material properties are often reduced. This paper considers powder bed fusion of polyamide 12 (PA12, Nylon 12) produced by three different processes: laser sintering (LS), multijet fusion (MJF)/high speed sintering (HSS), and large area projection sintering (LAPS). While all utilize similar PA12 materials, they are found to differ significantly in mechanical properties especially in elongation to break. The slower heating methods (MJF/HSS and LAPS) produce large elongation at break with the LAPS process showing 10x elongation and MJF/HSS exhibiting 2.5x the …

Experimental And Theoretical Investigation Of Mechanical Response Of Laser-Sintered Diamond Lattice Structures, Clayton Neff, Neil Hopkinson, Nathan B. Crane

Faculty Publications

Typically additive manufacturing (AM) processes are limited to a single material per part while many products benefit from the integration of multiple materials with varied properties. To achieve the benefits of multiple materials, the geometric freedom of AM could be used to build internal structures that emulate a range of different material properties such as stiffness, Poisson’s ratio, and elastic limit using only one build material. This paper examines the range of properties that can be simulated using diamond lattice structures manufactured from Nylon 12 with a commercial laser sintering process. Diamond lattices were fabricated with a unit cell length …