Engineering Commons^™

Heat Transfer Enhancement In Heat Exchangers Using Compound Enhancement, Mouhsine Benmbarek

UNLV Theses, Dissertations, Professional Papers, and Capstones

This research will try to investigate the enhancement of heat transfer in a heat exchanger that is made of a corrugated tube that has a twisted plate inserted in it, the corrugation, and twisted plate are expected to increase the amount of heat transfer since the plate is acting as a connection between the center of the flow and the edges of the tube. The turbulence will cause an increase in pressure drop along the channel length, so the investigation will try to find the best compromise between the gain in heat transfer and loss of hydraulic energy by using …

Evaluation, Rating, And Numerical Modeling Of A Shock Mitigation Seat For High-Speed Craft Based On Laboratory Single Impact Testing, Darren Benn

UNLV Theses, Dissertations, Professional Papers, and Capstones

High-speed craft (HSC) are utilized in military and para-military maneuvers that are usually conducted in harsh environments. The Special Warfare Combatant-craft Crewmen (SWCC), a sub-unit of the United States Naval Special Warfare Command (NAVSOC), use an advanced HSC, known as the Combatant Craft Assault, to conduct coastal patrol and interdiction, and for infiltration and exfiltration of Navy SEALs. The United States Coast Guard, and the Drug Enforcement Agency (DEA), employ HSC for maritime patrol and to pursue ‘go-fast’ boats operated by contraband runners. In most of these intense applications, the mode of operation of the HSC results in planing. Planing …

Remote Detection Of Leaks In High Level Waste Storage Tanks, Hunter Frey

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this research was to characterize three devices potentially capable of remotely detecting signatures of a leak from high-level waste (HLW) storage tanks, specifically ones found at the Savannah River Site and the Hanford Site. The hazard HLW found within these tanks include ¹³⁷Cs, a gamma-ray emitter, and ⁹⁰Sr, an electron emitter leading to heat generation. These pose health risks to the personnel and maintenance problems and environmental safety issues if released to the environment. Additionally, pinpointing the location of a leak is a task that could lead to the mitigation of excess waste leaking from …

Predicting The Response Of An Underactuated, 3d Printed Prosthetic Hand, Lucas Gallup

UNLV Theses, Dissertations, Professional Papers, and Capstones

The continuing need for hand prostheses has led to incredible developments in this area. However, due to the cost of the most sophisticated models, it is vital to develop simpler, low-cost, underactuated prostheses that can be produced rapidly. 3D printing is an important tool to achieve this goal. In particular, the 3D printed Flexy-Hand 2 has been one of the most common low-cost designs. A key feature of the Flexy-Hand 2 is its use of tendons and thermoplastic polyurethane (TPU) for joints that are strong and flexible. TPUs, however, lack a thorough understanding of their mechanical behavior, which makes it …

Performance Effects Of Dissociated Hydrogen In Nuclear Thermal Propulsion Engines, Richard Adam Gorrell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nuclear thermal propulsion (NTP) research considers hydrogen dissociation as negligible to design and analysis of propulsion engines. This study reintroduces chemically reacting flow to NTP engine analysis for investigation of the dissociation effect on engine performance. A first-principles approach observes the basic chemical mechanism and reaction within the high-speed, high-temperature NTP flow to baseline expected atomic hydrogen levels and validate equilibrium. A surface reaction study looks into hydrogen absorption through dissociation and its effect on the boundary layer, and bulk flow. For total performance, the resulting dissociated flow is analyzed through nozzle expansion and performance metrics calculated.

All historic reactor …

Redirection Of Current In A Dense Plasma Focus, Rocky Gonzalez

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Mission Support & Test Services (MSTS) reports that significant amounts of energy needed for generating high energy neutrons is lost within a Dense Plasma Focus between its pinch-end of the anode stalk and at its base near the insulating sleeve. It is their mission and the goal of this research effort to both experimentally and theoretically study current redirection in a DPF during and after pinch dynamics. It is hypothesized that current redirection, due to restrike, behind the dynamic sheath of a dense plasma focus will result in a measurable change in the magnetic field along the longitudinal axis …

Removal Of Permethrin And Bifenthrin Insecticides From Runoff Water By Activated Carbon Adsorption, Ernesto Hernandez

UNLV Theses, Dissertations, Professional Papers, and Capstones

Among the hundreds of pesticides and insecticides, pyrethroids-particularly permethrin and bifenthrin, have become very popular due to their high toxicity to insects and low toxicity to humans, leading to extensive use in both agriculture and urban areas. Pyrethroids have no discharge limits because of this, leading to a negative impact on surrounding ecosystems due to their high toxicity to fish and aquatic life. Due to their low solubility and long half-lives, they are prominent in the environment long after application with a high potential for getting transported in runoff water to nearby water bodies. In this study, DSR-C reactivated carbon …

Boron-Doped Diamond As A Resilient Electrode Material In Molten Salts, Hannah Katherine Patenaude

UNLV Theses, Dissertations, Professional Papers, and Capstones

Molten salt chemistry has a range of applications within nuclear technology, including for the Molten Salt Reactors (MSRs) and pyroprocessing to recover valuable actinides for energy and national security needs. However, the high-temperature, corrosive nature of molten salts makes them particularly challenging to deploy on an industrial scale and study in benchtop measurements. Material accountability and corrosion monitoring of MSR fuels are essential components to the successful deployment of MSRs, and electroanalytical techniques like cyclic voltammetry (CV) and spectroelectrochemistry (SEC) can provide a wealth of information to describe salt systems in situ. To perform such measurements, it is imperative to …

Assessment Of Success Factors And Comparative Analysis Of Public Private Partnership (P3) Project Performances Against Design-Build And Design-Bid-Build Project Delivery, Bandana Shrestha

UNLV Theses, Dissertations, Professional Papers, and Capstones

Public-private partnerships (P3s) projects have gained widespread popularity in both developed and developing countries due to their ability to access new financing sources and shift specific project risks to the private sector. P3s has been an active area of research with a particular focus on the concept of Critical Success Factors (CSF). The growing interest and the diverse outcomes associated with P3s emphasize the need for a thorough investigation into the factors that contribute to successful P3 projects. This study focused on identifying the CSFs for P3 highway and building projects towards project objectives of achieving cost efficiency and schedule …

Final Design Of Legion Hall Revitalization In Potter, Nebraska, Madison Brennfoerder

Honors Program: Senior Projects (Public)

This project was conducted to renovate and revitalize the Legion Hall community center in the Village of Potter located in western Nebraska north of the Interstate. The work completed for this project can be separated into five disciplines: Hydrologic & Hydraulic Design, Geotechnical Analysis, Structural Analysis, Environmental Analysis, and Transportation Design. Legion Hall is a historical building within The Village of Potter which was built in 1917. The Village of Potter has recently acquired the rights to the hall and is seeking to revitalize the historical community center to increase tourism in the village.

A Parametric Study On The Energy Dissipation Capability Of Frictional Mechanical Metamaterials Engineered For Vibration Isolation, Shayan Khosravi, Mohsen Amjadian

Civil Engineering Faculty Publications

Mechanical metamaterials are engineered structures with complex geometric arrangements that display unconventional mechanical properties which are uncommon in traditional materials. They possess the ability to manipulate and control mechanical wave propagation across specific frequency ranges known as frequency bandgaps. This feature makes them extremely useful for a variety of applications in structural control including passive vibration isolation. These materials can be engineered to selectively block or redirect the input motion at their dominant frequency while allowing the transmission of motion at other frequencies. This paper aims to study the dynamic performance of an innovative mechanical metamaterial designed for seismic isolation …

Detection Of Deficiencies And Data Analysis Of Bridge Members With Deep Convolutional Neural Networks, Bennett Jackson

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Concrete cracks and structural steel corrosion are two of the most common defects in bridges. Quantifying and classifying these defects provide bridge inspectors and engineers with valuable data for assessing deterioration levels. However, the bridge inspection process is typically a subjective, time intensive, and tedious task, as defects can be overlooked or in locations not easily accessible. Previous studies have investigated deep learning-based inspection methods, implementing popular models such as Mask R-CNN and U-Net. The architectures of these models offer certain advantages depending on the required task. This thesis aims to evaluate and compare Mask R-CNN and U-Net regarding their …

Breakaway Luminaire Pole Research, Jacob Conway

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

This document reports the efforts conducted to determine critical parameters and configurations for Manual for Assessing Safety Hardware 2016 (MASH) Test Level 3 (TL-3) compliant breakaway luminaire poles supported by slip bases, including identifying pole configurations with the potential to meet MASH TL-3 as well as recommending critical configurations for full-scale crash testing. A thorough literature review was conducted which included survey results collected from Midwest Pooled Fund state departments of transportation (DOTs), standard plans from state DOT’s, and past luminaire pole testing.

Numerical LS-DYNA models were developed for luminaire poles with 4-bolt slip base utilized by the Utah Department …

Sliding Markov Decision Processes For Dynamic Task Planning On Uncrewed Aerial Vehicles, Trent Wiens

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Mission and flight planning problems for uncrewed aircraft systems (UASs) are typically large and complex in space and computational requirements. With enough time and computing resources, some of these problems may be solvable offline and then executed during flight. In dynamic or uncertain environments, however, the mission may require online adaptation and replanning. In this work, we will discuss methods of creating MDPs for online applications, and a method of using a sliding resolution and receding horizon approach to build and solve Markov Decision Processes (MDPs) in practical planing applications for UASs. In this strategy, called a Sliding Markov Decision …

Dynamic Impact Testing And Numerical Analysis Of Non-Proprietary Astm F2656-20 M50 Anti-Ram Barrier Components, Weston Kelley

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

In a post-9/11 world, hostile actors are using vehicles as weapons to inflict civilian casualties. Pedestrians, vulnerable road users, military personnel, and police may be targeted using a vehicle as a weapon. The United States Department of Defense (DoD) also utilizes Entry Control Facilities (ECFs) which are carefully designed transportation corridors to manage how threat vehicles are able to access military facilities. In 2004, DoD started to upgrade all ECFs using both passive and active barriers. Many anti-ram vehicle barriers were evaluated according to the criteria established in ASTM F2656, but to date few options are available which are (1) …

The Effect Of Extended Saltwater Absorption And Uv Cure On The Compressive Properties Of Msla 3d-Printed Photopolymer Resin Samples With Printing Variations, Suzanne Dixon

Theses and Dissertations

Liquid Crystal Display (LCD) 3D printers, also known as Masked Stereolithography Apparatus (MSLA), is a type of vat polymerization printing technique that cures liquid resin into a solid object. This technique is relatively new. Consequently, there is a shortage of detailed research on the impact of long-term environmental exposure on the MSLA-printed materials. The research within this document informs engineers and scientists of resin compressive properties after extended exposure to saltwater and ultraviolet (UV) light. Saltwater absorption of the material was analyzed at atmospheric pressure, 30-psi, 60-psi, and 90-psi; the samples reached saturation in saltwater after 56 days. The variation …

Caelus: Cubesat Array For The Exploration Of The Uranus System, Dylan George Heidenrich Barnes

Theses and Dissertations

Following recommendations from the 2023-2032 Planetary Science and Astrobiology Decadal Survey, we propose a novel Pre-Phase A level Uranus exploration mission concept that is centered on using swarms of small spacecraft to observe the Uranus system. This mission could act as a supplement to the Flagship Uranus Orbiter and Probe mission detailed in said Decadal Survey. We propose launching a 4,500 kg spacecraft on an Earth-Jupiter-Uranus gravity assist transfer trajectory with a transfer time of six years, launching in 2033 and arriving at Uranus in 2039. This shorter transfer time and accelerated development timeline would allow for an earlier arrival …

Denoising Diffusion Probabilistic Models Based Accelerated Mri, Alexander Francis Bugielski

Theses and Dissertations

Magnetic Resonance Imaging (MRI) is a cornerstone in obtaining intricate visualizations of anatomy and physiological processes within the human body. However, its extensive scan duration not only causes patient discomfort but also increases the likelihood of motion-induced artifacts in the images. To address such a challenge, this study investigates deep neural network models for reconstructing high-resolution MRI images from noisy and significantly undersampled data in a supervised learning manner. Specifically, it compares three models: a conventional U-Net, a self-attentive U-Net, and an innovative probabilistic diffusion model that builds upon the self-attentive U-Net architecture. These models are evaluated on their ability …

Computational Fluid Dynamics Study Of Perforated Monopiles, Mary Kathryn Walker

Theses and Dissertations

Monopiles are used in the construction of offshore wind turbines and typically have a design life of 25 to 50 years. Over their lifecycle, monopiles are exposed to a corrosive saltwater environment, facilitating a galvanic oxidation process that quickly degrades the structure. This process can be mitigated by coating the monopile in a protective barrier and implementing cathodic protection techniques. Historically, monopile designers assumed the interior of the pile would be completely sealed and the galvanic corrosion process would eventually consume all the available oxygen, halting the reaction. However, penetrations made in the pile wall for conduit often leaked and …

Investigating Factors Influencing Blockchain Adoption In Saudi Healthcare Data Management, Noura Mohammad Alkhalifah

Theses and Dissertations

Blockchain technology can potentially address security and privacy issues concerning the collection, storage, and sharing of healthcare data. However, its adoption within the healthcare sector is nascent in Saudi Arabia. This underutilization prompted our investigation into the determinants influencing blockchain adoption, intending to fully empower the Saudi healthcare sector to leverage blockchain capabilities. To achieve this, an extensive literature review was conducted to identify the pivotal factors encompassing technology, organization, and environment (TOE) that affect the successful implementation of blockchain technologies in managing healthcare data within the Saudi context. Utilizing the TOE framework, this study formulated three hypotheses concerning the …

Deep Learning System Identification, Linearization And Control Of Dynamical Systems Utilizing Koopman Theory With Applications In Orbital Systems, George Mario Nehma

Theses and Dissertations

The computational and complexity burden of current linearization techniques is one that is a hinderance in the application of real world guidance, navigation and control systems. With the advancements in Deep Neural Networks, large data handling and Koopman Theory, the possibility of global linearizations of nonlinear systems is more prominent. This work demonstrates the capability of a Deep Neural Network learned Koopman operator to transform a nonlinear system into a Linear Time-Invariant system. The method presented is applied to both two purely dynamical systems and one controlled system to emphasize the ability for the technique to be applied in all …

Impervious Surfaces From High Resolution Aerial Imagery: Cities In Fresno County, Yushin Ahn, Richard Poythress

Mineta Transportation Institute

This study investigates impervious surfaces — areas covered by materials with restricted water permeability, such as pavement, sidewalks, and parking lots—due to their crucial role in influencing water dynamics within urban landscapes. The impermeability of these surfaces disrupts natural water absorption processes, resulting in adverse environmental consequences such as increased flooding, erosion, and water pollution. The research employs impervious surface analysis, a method involving the mapping and analysis of these surfaces within specified study areas, including cities, counties, and census tracts. Remote sensing techniques, specifically satellites and aerial imagery, are commonly utilized for the identification and classification of impervious surfaces. …

Does California High-Speed Rail Promote Accessibility For Station Cities?: Case Study Of Fresno And Merced, Chih-Hao Wang, Na Chen

Mineta Transportation Institute

California High-Speed Rail (CHSR) will largely change transportation cost across the state after it starts operating. Past studies show that only Fresno and Merced among station cities in the Central Valley would attract more future activities with the CHSR. The establishment of active CHSR also implies a new daily living sphere for all the station cities, and, therefore, accessibility to work and residential amenities should be reviewed to inform planners of future land-use and transportation developments. A research framework has been developed better to understand the impact of CHSR on job and amenity accessibility by driving, transit, and walking in …

An Adaptive Large Neighborhood Search For The Multi-Vehicle Profitable Tour Problem With Flexible Compartments And Mandatory Customers, Vincent F. Yu, Nabila Yuraisyah Salsabila, Aldy Gunawan, Anggun Nurfitriani Handoko

Research Collection School Of Computing and Information Systems

The home-refill delivery system is a business model that addresses the concerns of plastic waste and its impact on the environment. It allows customers to pick up their household goods at their doorsteps and refill them into their own containers. However, the difficulty in accessing customers’ locations and product consolidations are undeniable challenges. To overcome these issues, we introduce a new variant of the Profitable Tour Problem, named the multi-vehicle profitable tour problem with flexible compartments and mandatory customers (MVPTPFC-MC). The objective is to maximize the difference between the total collected profit and the traveling cost. We model the proposed …

Valorization Of Date Palm Waste For The Isolation, Characterization, And Surface Chemistry Modification Of Nanocellulose, Mohsin Raza

Dissertations

This dissertation focuses on the utilization of date palm waste, a lignocellulosic material, as a source for the extraction of nanocellulose (NC), a versatile biopolymer with applications in biodegradable composites, bioplastics, and food packaging. Conventional methods of NC production using mineral acids such as sulphuric and hydrochloric acid are reaching their limits of toxicity, so more environmentally friendly alternatives such as ionic liquids (ILs) are being explored. The research focuses on the characterization of different date palm wastes to evaluate their α−cellulose content, lignocellulosic character, and thermal stability. By comparing extraction methods with mineral acids and ILs, the study evaluates …

Retrofit Prioritization Of Substandard Buildings For Earthquake Risk Management, Roshen John Joseph

Dissertations

Despite the pressing need for risk mitigation techniques for reinforced concrete (RC) structures designed without considering seismic design provisions, limited research has focused on selecting experimentally verified retrofit measures from various alternatives, particularly considering minimizing disruption to operating real-life buildings. Against this backdrop, this study is directed toward selecting reliable and costeffective retrofit techniques for improving the seismic performance of substandard RC buildings with different structural systems and heights common in medium seismicity regions. Contemporary retrofit approaches are investigated, including polyparaphenylene benzobisoxazole fiber-reinforced cementitious matrix (P-FRCM) composites, carbon FRCM (C-FRCM) composites, thin high-performance reinforced concrete (HPRC) jackets, and self-centering energy …

Quantifying Image Quality In Aoslo Images Of Photoreceptors, Brea D. Brennan, Heather Heitkotter, Joseph Carroll, Sergey Tarima, Robert F. Cooper

Biomedical Engineering Faculty Research and Publications

The use of “quality” to describe the usefulness of an image is ubiquitous but is often subject to domain specific constraints. Despite its continued use as an imaging modality, adaptive optics scanning light ophthalmoscopy (AOSLO) lacks a dedicated metric for quantifying the quality of an image of photoreceptors. Here, we present an approach to evaluating image quality that extracts an estimate of the signal to noise ratio. We evaluated its performance in 528 images of photoreceptors from two AOSLOs, two modalities, and healthy or diseased retinas. The algorithm was compared to expert graders’ ratings of the images and previously published …

Germanium-Tin On Silicon For Integrated Photonics And Integrated Quantum Materials, Shang Liu

Dartmouth College Ph.D Dissertations

Group IV GeSn alloys are attracting attention due to their compatibility with the complementary metal-oxide-semiconductor (CMOS) process. On one hand, Ge-rich GeSn alloys with a tunable direct bandgap are well-suited to infrared (IR) photonic applications such as image sensors. On the other hand, Sn-rich GeSn alloys in diamond cubic α phase are topological quantum materials (TQM) holding potential for important quantum applications. However, directly growing GeSn on Si remains challenging due to the lattice mismatch. Regular epitaxial GeSn grown on a Ge buffer layer is not applicable to many photonic applications including CMOS image sensors (CIS) because the buffer layer …

Deep Learning Using Vision And Lidar For Global Robot Localization, Brett E. Gowling

Master's Theses

As the field of mobile robotics rapidly expands, precise understanding of a robot’s position and orientation becomes critical for autonomous navigation and efficient task performance. In this thesis, we present a snapshot-based global localization machine learning model for a mobile robot, the e-puck, in a simulated environment. Our model uses multimodal data to predict both position and orientation using the robot’s on-board cameras and LiDAR sensor. In an effort to minimize localization error, we explore different sensor configurations by varying the number of cameras and LiDAR layers used. Additionally, we investigate the performance benefits of different multimodal fusion strategies while …

A Smart Hybrid Enhanced Recommendation And Personalization Algorithm Using Machine Learning, Aswin Kumar Nalluri

Electronic Theses, Projects, and Dissertations

In today’s age of streaming services, the effectiveness and precision of recommendation systems are crucial in improving user satisfaction. This project introduces the Smart Hybrid Enhanced Recommendation and Personalization Algorithm (SHERPA) a cutting-edge machine learning approach aimed at transforming how movie suggestions are made. By combining Term Frequency Inverse Document Frequency (TF-IDF) for content based filtering and Alternating Squares (ALS) with Weighted Regularization for filtering SHERPA offers a sophisticated method for delivering tailored recommendations.

The algorithm underwent evaluation using a dataset that included over 50 million ratings from 480,000 Netflix users encompassing 17,000 movie titles. The performance of SHERPA was …