Engineering Commons^™

Fast Neutron Assay Of Elemental Content Of Bulk Samples, Calder Emerson Lane

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this research was to analyze the capabilities of fast neutrons in the detection and analysis of various isotopes in bulk samples. The deuterium-tritium (DT) fusion reaction generates highly penetrating, high-energy (14.1-MeV) neutrons which induce nuclear reactions in irradiated targets. Neutrons and gamma rays are generated in these reactions. Emitted gamma rays are characteristic of the emitter; the gamma spectrum enables stoichiometric identification of the assayed samples. Neutron backscattering can also be used for identification of the elemental composition of the sample.

This work had three objectives. The first objective was to develop a computational technique to model …

A Circle Hough Transform Implementation Using High-Level Synthesis, Carlos Lemus

UNLV Theses, Dissertations, Professional Papers, and Capstones

Circle Hough Transform (CHT) has found applications in biometrics, robotics, and imageanalysis. In this work, the focus is the development of a Field Programmable Gate Array (FPGA) based accelerator that performs a series of procedures and results in circle detection. The design is performed using Vivado High-Level Synthesis (HLS) tools and targeted for a Zynq UltraScale+ ZCU106. The implementation includes the following procedures: Gaussian filter, Sobel edge operator, thresholding, and finally the CHT algorithm. The performance is evaluated based on the execution time as compared to the software (Python code) execution and the analysis tools provided by Vivado HLS tool. …

Minimizing Visual Defects Through Augmentation Of Computer Aided Diamond Rough Planning, Abhijith Prabhu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Many computer aided design systems today utilize a workflow where physically accurate rendering of the product is not a functional component of its design process. This gap in workflow can lead to a sub optimal product or even a longer iterative design process in instances where a product's visual attributes and aesthetics are one their primary functional characteristic.

Diamonds are graded on their carat, color, clarity and cut, referred to as the 4Cs of a diamond; a standard set by G.I.A. and universally agreed upon. The cut of a diamond significantly affects the rest of the characteristics as it modifies …

Alternate Novel Thermal Structure Interaction Designs Of Molten Salt Shell Structures At High Temperatures Ranging From 565˚C To 700˚C, Nathan David Tyrrell Loyd

UNLV Theses, Dissertations, Professional Papers, and Capstones

Excess energy from solar power stations and other baseline power production methods canbe stored in molten salts (MS) in the 565°C range, therefore allowing the use of large containers to store energy for up to a week and generate eight hours of electricity or more to be used during peak demand hours, at night, or adverse weather conditions, depending on the container size. Supported by Office of Naval Research (ONR), this research presents a survey of molten salt properties used in solar power storage, as well as the history of molten salt usage for energy storage and production for nuclear …

A Multi-Channel Mcp-Pmt Based Readout Integrated Circuit For Lidar Applications, Sachin Purushothaman Namboodiri

UNLV Theses, Dissertations, Professional Papers, and Capstones

Photon counting techniques are becoming more critical in fields such as LiDAR, high energy physics (HEP), and positron emission tomography (PET). For space-based aerosol-cloud-ocean (ACO) LiDAR, the total aggregate photon flux signal has a very high dynamic range, from a single-photon up to giga-photons per second for a single channel. This dissertation focuses on the design of a multichannel, photon counting readout circuit that can interface with MCP-PMTs for high dynamic range, space-based LiDAR applications. Chapter 2 presents the conventional current mode approach that has been employed to realize a photon counting circuit. A transimpedance amplifier, a 6-bit delay line …

Design And Fabrication Of A 6-Bit Current-Mode Adc For Lidar And High-Speed Applications, Jason Silic

UNLV Theses, Dissertations, Professional Papers, and Capstones

The design, simulation, fabrication, and testing of a 6-bit current-mode ADC is presented with related calculations. Capable of producing samples at greater than 100MHz, the proposed design should excel at measuring fast current transients such as those produced by arrays of avalanche photodiodes (APDs). An array of 63 current comparators feed digital logic gates, via “thermometer code,” that produce a 6-bit output word that is driven off-chip by appropriate buffers.The circuit was designed using Cadence Virtuoso design software. Simulated Differential Non-Linearity (DNL), with an 8µA reference current, is 1.656 LSB at the worst transition involving a scale change. Excluding scale …

Developments Of Machine Learning Potentials For Atomistic Simulations, Howard Yanxon

UNLV Theses, Dissertations, Professional Papers, and Capstones

Atomistic modeling methods such as molecular dynamics play important roles in investigating time-dependent physical and chemical processes at the microscopic level. In the simulations, energy and forces, sometimes including stress tensor, need to be recalculated iteratively as the atomic configuration evolves. Consequently, atomistic simulations crucially depend on the accuracy of the underlying potential energy surface. Modern quantum mechanical modeling based on density functional theory can consistently generate an accurate description of the potential energy surface. In most cases, molecular dynamics simulations based on density functional theory suffer from highly demanding computational costs. On the other hand, atomistic simulations based on …

Impact Of Disadvantaged Business Enterprises Participation And Mobilization Cost On Highway Project Performance, Shristy Maharjan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Construction practitioners have their goals to complete projects within time without exceeding the allocated budget. However, studies have shown many projects overrun their allocated budget and face delays due to numerous reasons. Some of the main reasons are lack of efficient construction and financial resource management, lack of proper planning, and unavailability of new construction technologies, as well as ineffective supervision and communication, design changes, and unskilled workers. In some studies, mobilization costs, along with the participation of Disadvantaged Business Enterprises (DBEs) in projects were identified as factors affecting the cost and schedule performance of construction projects. However, no statistical …

Fighter Aircraft Guidance And Control, Kaushik Raj

UNLV Theses, Dissertations, Professional Papers, and Capstones

Aircraft technology has undergone momentous improvements over the decades due to the growing demand and competition among industries. The performance requirement and stability of fighter aircraft is a major factor due to the ever-increasing flight envelope. Advanced fighter aircraft are expected to be highly maneuverable. To achieve extreme maneuverability a very good aircraft design with multiple redundant control actuators having static instabilities in certain modes, near accurate nonlinear aircraft mathematical model, and suitable nonlinear control design technique is required. Conventionally, training aircrafts such as Cessna and Piper aircraft are built for static and dynamic stability, making them easy to trim …

Closed-Loop Propulsive Control For Very Low Perigee Orbit Energy Management And Stabilization, Tyler J. Gardner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Within the past decade, the United States Air Force has begun exploring options for using smaller satellites, known as SmallSats and CubeSats, to decrease the time it takes to design and build new satellites. If used properly, a rapid development environment for satellites could improve the Air Force's ability to respond to new technologies and threats. Other organizations such as NASA and universities have been using SmallSats and CubeSats for research and development missions.

While smaller satellites are usually much cheaper to develop and require less time to create, limited volume strictly constrains the size of instrumentation and avionics that …

Hydraulic Analysis Of Coupling A Labyrinth Weir With A Steep Stepped Chute, Tucker J. Jorgensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

There are many considerations involved in the design of a dam structure. A few of these include minimizing upstream flooding (and risk of embankment overtopping), economical construction, and downstream erosion. Addressing these concerns has, in part, led to a recent increase in the use of more efficient and economical hydraulic. Complex hydraulic structures such as labyrinth weirs and stepped chutes require extensive study to establish design methods. Combining two complex structures can result in dramatic changes in flow characteristics. This is particularly true in the case of combining a labyrinth weir with a stepped chute. Flow from the labyrinth weir …

Soft-Switched Resonant Dc-Dc Converter In Underwater Dc Power Distribution Network, Tarak Saha

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Power distribution with DC source is advantageous over its AC counterpart in long distance distribution network due to the absence of effects of reactive components. Long distance power distribution with traditional voltage source suffers from drop in voltage over the length of the cable due to its impedance and forces the converters in the network to be over-designed with higher power rating than needed. In underwater power distribution network such as ocean observatory, marine sensors on the sea-bed etc., power conversion modules are situated at a distance far away from the shore, ranging from tens of kilometers to hundreds of …

"You Can Tell They Care": A Phenomenographic Study Of Student Experiences With Empathic Concern Expressed By Professors In Engineering, Kate Youmans

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In order to address the increasingly complex challenges of the 21st century, there is a need to continue to grow the technical workforce by improving graduation rates of engineering students. To accomplish this, the culture of engineering programs must shift from demanding or intimidating to more inclusive and supportive. Professors can play a critical role in creating these cultures by building relationships with students. Empathic concern is essential in building relationships that can encourage student growth and development. This form of empathy, sometimes referred to as care or concern, is expressed through actions of understanding, compassion, and non-judgement. While research …

Fate Of Pharmaceuticals And Personal Care Products In Duckweed And Waste Activated Sludge Under Aerobic And Anaerobic Solids Stabilization Conditions, Kwame Tweneboah Duodu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Twelve commonly used pharmaceuticals and personal care products (PPCPs)(acetaminophen, β-Estradiol, caffeine, carbamazepine, DEET, estrone, gemfibrozil, triclosan, TCEP, sulfamethoxazole, progesterone, fluoxetine) were investigated to determine their fate in biosolids. These compounds were selected due to their wide usage, and varying properties, that makes them representative of many other PPCPs.

Commonly used PPCPs (caffeine commonly found in tea, coffee, chocolate and soda, the pain reliever acetaminophen, and the pesticide DEET) were detected in high amounts in the influent of the Hyrum WWTP and Wellsville sewage lagoons. Although conventional WWTPs are not designed to remove PPCPs from wastewater, some PPCPs, such as acetaminophen, …

Analytic Guidance Strategies For Passively Safe Rendezvous And Proximity Operations, Simon Shuster

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A safety ellipse is a type of relative motion trajectory that is commonly used for unmanned rendezvous and proximity operations. As the name suggests, safety ellipses are passively safe relative motion trajectories, which means that their natural motion inherently maintains a low collision risk. The focus of this dissertation is the derivation, analysis, and application of guidance strategies that reconfigure, establish, and exit a safety ellipse. The guidance strategies consist of a set of ∆v vectors and impulse times, all written in closed form. Through applications of optimal control theory and parameter optimization, it is shown that these maneuver …

The Effect Of Weather On Pedestrian Activity At Signalized Intersections In Utah, Ferdousy Runa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The weather has a significant influence on pedestrian activity. Profound knowledge and research can identify how weather variables impact and why people change their travel patterns. This study aims to assess the relationship of weather (snowfalls, snow depth, precipitation, maximum and minimum temperature) with pedestrian activity at 49 signalized intersections in Cache County, Utah. This study uses pedestrian actuation (push-button) data as a proxy for pedestrian activity and collects weather data from the National Oceanic and Atmosphere Administration (NOAA).

Using 15 months of daily time-series data, this study applied log-linear time series models in the analysis. To account for non-linear …

Characterizing Water And Water-Related Energy Use In Multi-Unit Residential Structures With High Resolution Smart Metering Data, Joseph C. Brewer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As urban populations continue to grow and expand, localized demands on water supplies continue to increase as well. These water supplies, which have been historically stable, are also threatened by an increasingly erratic climate. Together, these two factors have significantly increased the likelihood of long-term drought conditions in the American West. In response, water suppliers are investigating new ways to record water use in urban areas to better understand how water is used. One of these methods is smart meters; advanced devices that can record and transmit water use information directly to the water supplier. However, these devices can produce …

Emerging Works On Wireless Inductive Power Transfer: Auv Charging From Constant Current Distribution And Analysis Of Controls In Ev Dynamic Charging, Anindya Chitta Bagchi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wireless power transfer through inductive coupling, termed as inductive power transfer (IPT), is one of the important technologies in power electronics that enable transfer of power between entities without physical connections. While it has seen significant growth in the areas such as electric vehicle charging, phone charging and biomedical implants, its emerging applications include charging of autonomous underwater vehicles (AUVs) and dynamic charging of electric vehicles from the roadway. This dissertation addresses a few key challenges in these areas of IPT applications, paving the way for future developments.

For the WPT for AUV, the recently developing sea-bed installed marine systems …

Self-Describing Fiducials For Gps-Denied Navigation Of Unmanned Aerial Vehicles, Amanda J. Strate

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Accurate estimation of an Unmanned Aerial Vehicle’s (UAV’s) location is critical for the operation of the UAV when it is controlled completely by its onboard processor. This can be particularly challenging in environments in which GPS is not available (GPS-denied). Many of the options previously explored for estimation of a UAV’s location without the use of GPS require more sophisticated processors than can feasibly be mounted on a UAV because of weight, size, and power restrictions. Many options are also aimed at indoor operation without the range capabilities to scale to outdoor operations. This research explores an alternative method of …

Molecular Mechanisms And Design Of Hydrogen-Bonded Materials For Thermal Applications, Jinlong He

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Heat transfer at the nanoscale plays an important role in determining the reliability and performance of many innovative advanced materials technologies such as nanoelectronics, semiconductor, biomedical devices, polymers, and composites. Extensive efforts have been made to design materials with extraordinary thermal properties. However, fundamental understanding of heat transfer in many of these materials is still not lacking, because the thermal transport processes are governed by several factors including molecular morphology and chemical bonding. Among these factors, the atomic bonding between two dissimilar materials or within single materials is of particular interest due to its ubiquity and importance in physical processes. …

Systems Thinking In Engineering Design: Differences In Expert Vs. Novice And Relationship To Personality Traits, Yuzhen Luo

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Systems thinking is the ability to see the big picture and the related elements when designing, and how these relationships form the big picture. In engineering design, systems thinking is valuable to both industry, as well as engineering education. As such, it creates opportunities for researchers to better understand systems thinking of both professional engineers in industry, who are assumed to be the experts, and engineering students in higher education, who are assumed to be the novices. The purpose of this study was to compare and identify the differences between expert and novice systems thinking in engineering design. Additionally, the …

Development Of Molecular Sensor And Imaging Analysis Techniques For Improving Life Quality, Wei Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As life science advances, we are getting closer and closer to understanding the truth about life. Some specific cell types or molecules play a vital role in regulating routine functions of life. The imperceptible changes of these critical components can lead to serious diseases. Traditionally, histopathological techniques are widely employed to study and diagnose human diseases. However, these methods are time consuming and invasive. Herein, we introduce multiple types of biosensors that are sensitive, easy to use and most importantly non-invasive. First, I developed a smartphone based colorimetric sensor for detection of water hardness in a convenient way by introducing …

Exploring The Feasibility Of Introducing Alternative Fuel Vehicles Into Fleet, Samia Rubaiat

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Transportation is one of the most significant contributing sectors to emissions and consequently air pollution in the United States. Many state and private fleet agencies have announced their visions of zero-emission fleet programs. Adopting alternative fuel vehicle (AFV) is a viable option for achieving this objective. AFVs offer lower emissions along with low operating and maintenance costs, and higher fuel economy. The advancement of technologies has provided several AFV options, such as hybrid electric vehicles (HEV), electric vehicles (EV), compressed natural gas vehicles (CNGV), and liquefied petroleum gas vehicles (LPGV). The main challenges in adopting AFVs are the high purchasing …

Stem Education In College: An Analysis Of Stakeholders’ Recent Challenges And Potential Solutions, Santanu De, Georgina Arguello

FDLA Journal

A vast majority of academic disciplines and curricula in the college center around Science, Technology, Engineering, and Mathematics (STEM), which are critical to developing the skills necessary for a global workforce. Rapid changes in pedagogical setups, educational modes, and advances in instructional technology entail diverse challenges for key stakeholders (i.e. students, faculty, and the organizations). This paper highlights the most relevant challenges and potential solutions in STEM higher education at the college level, reported in the last decade. The holistic analysis combining the three stakeholders’ perspectives would help elucidate significant contemporary aspects impacting the fields. The goal is to further …

Comparison Between Nano-Hydroxyapatite And Cpp-Acpf In Remineralizing Early Carious Lesions (In Vitro Study), Raneem Saudi, Mohamed A. Ibrahim

BAU Journal - Creative Sustainable Development

Poor oral hygiene, bacteria and orthodontic appliances mainly lead to early demineralized lesions where early detection and diagnosis of the lesion is a must so that it can be assessed and cured with the least invasive treatment. The objective was to evaluate the effect of nano-hydroxyapatite (nano-HA) and casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF) on early demineralized enamel using DIAGNOdent pen and energy dispersive X-ray analysis (EDX). Materials and methods: A total of 60 enamel specimens were divided into four groups (n=15), where Group A: experimental; treated with nano-HA tooth paste, Group B: self-control for group A, Group C: experimental; …

Specifying Space Defense Operator Interfaces Through The Application Of Cognitive Systems Engineering And Prototyping, Justin E. Oryschak

Theses and Dissertations

The Department of Defense needs better tools to support its operators as they strive to defend its space assets. The growing sophistication of anti-satellite weapons increasingly challenges the nation’s orbital communications and surveillance infrastructure. Operators face difficulties gathering useful information and dealing with the complexity of potential enemy actions. This research applied cognitive systems engineering and ecological interface design (EID) methodologies to create a prototype space mission management tool that enhances operator situation awareness and decision-making ability. Applied cognitive task analysis interviews were used to document space operator decision-making in their domain. Model-based systems engineering was applied to integrate work …

Willingness To Pilot In Different Aircraft Sanitization Scenarios, Nicholas Valluzzi, Jesse Shacknai, Brooke Wheeler, Tianhua Li

Aeronautics Student Publications

A stratified sample of Part 141 ground school classes participated in a questionnaire which determined their willingness to pilot among four different aircraft sanitization scenarios. The sanitization scenarios with more precautions resulted in an increased willingness to pilot.

Dynamic Body-Weight Support To Boost Rehabilitation Outcomes In Patients With Non-Traumatic Spinal Cord Injury: An Observational Study, Justin P. Huber, Lumy Sawaki

Neurology Faculty Publications

BACKGROUND: Dynamic body-weight support (DBWS) may play an important role in rehabilitation outcomes, but the potential benefit among disease-specific populations is unclear. In this study, we hypothesize that overground therapy with DBWS during inpatient rehabilitation yields greater functional improvement than standard-of-care in adults with non-traumatic spinal cord injury (NT-SCI).

METHODS: This retrospective cohort study included individuals diagnosed with NT-SCI and undergoing inpatient rehabilitation. All participants were recruited at a freestanding inpatient rehabilitation hospital. Individuals who trained with DBWS for at least three sessions were allocated to the experimental group. Participants in the historical control group received standard-of-care (i.e., no DBWS). …

Photoacoustic Co2 Detection In Biomass Cookstove Applications, Jacob Matthew Thomas

Theses and Dissertations

Billions of people use biomass burning cookstoves in their homes and suffer serious health repercussions. Additionally, global warming is exacerbated by cookstove emissions containing greenhouse gases and particulate matter. Improved cookstoves (ICSs) mitigate the problem, but accurate and affordable emission gas measurements, particularly of Carbon Dioxide (CO2) and Carbon Monoxide (CO), are required in order to confidently declare ICSs cleaner burning than traditional cookstoves. The aim of this research is to assess the suitability of photoacoustic (PA) CO2 detection technology for cookstove emissions monitoring. The designs of several longitudinally resonant, photoacoustic, LED, CO2 sensors of varying levels of functionality are …

Design Of A Single-Carrier Pulse Width Modulation With Submodule Fault-Tolerant Capability For Modular Multilevel Converter, Tuanku Badzlin Hashfi

Student Works (2020-2029)

Multilevel converters are attracting a lot of attention and becoming one of the energy conversion choices for new topologies and control in industry applications and research fields. Modular multilevel converters (MMCs) are considered very promising among converter topologies for future medium-voltage and high-power applications compared to NPC, FC and CHB topologies. The improved phase disposition pulse width modulation (PDPWM) technique control for MMCs, which has a fault-tolerant capability, is presented. This study presents two methods to distribute pulses into submodules (SMs) by using PDPWM which has drawback to distribute the power equally among the submodules (SMs). First method, this study …