Engineering Commons^™

A Unified Understanding Of Minimum Lattice Thermal Conductivity, Yi Xia, Dale Gaines, Jiangang He, Koushik Pal, Zhi Li, Mercouri G. Kanatzidis, Vidvuds Ozolinš, Chris Wolverton

Mechanical and Materials Engineering Faculty Publications and Presentations

We propose a first-principles model of minimum lattice thermal conductivity based on a unified theoretical treatment of thermal transport in crystals and glasses.

Generation Of Plasma With A Rotating Electric Field, Franklin Price Mosely

Electrical & Computer Engineering Theses & Dissertations

Nonthermal plasma generation is an important area of research that has many applications ranging from semiconductor production to medical applications including the treatment of cancers and sterilization of surfaces. Specific radicals and excited species and discharge powers are critical for the successful completion of these processes. It is important that these excited species are shown to be achievable for a given discharge system without leading to instabilities such as arcing.

The present thesis details the design, fabrication, testing, and analysis of a novel plasma generation system based on multiphase excitation. As predicted by theory, the experimental results demonstrate that a …

Innovation For The Air: A Brief History Of Worldwide Aviation, Lauren Plumley

Honors Program: Senior Projects (Public)

The purpose of this report is to present a brief but comprehensive overview of the variety of innovations related to aviation, and to discuss their impact on scientific progress over the course of human history. Relevant discoveries from the fields of physics and aerodynamics, and the numerous technologies built based upon these discoveries, are discussed over a period ranging from ancient times to the twenty-first century. The scope of this report is an overview of the development of powered and unpowered aircraft, including lighter-than-air, heavier-than-air, and aerospace technologies. Aviation developments were generally not limited to one specific country or person, …

Mechanical And Thermal Performance Of Additively Manufactured Digital Materials, Layth Muayyad Ahmad

Mechanical and Aerospace Engineering Theses - Archive

Over the past decades, additive manufacturing has become a critical material processing tool. All ranges of materials including polymers, composites, metals, and ceramics can be used to fabricate structures with complex geometries that are nearly impossible to build using conventional fabrication process. Recently, additive manufacturing methods to build polymeric structures have been advanced significantly. In particular, the emergence of multi-material printers has made it possible to seamlessly print hybrid and digital materials where materials components and compositions are digitally varied to construct fully tailored material system. In this work, using a commercially available polyjet printer (Stratasys J850 Prime 3D printer), …

Parametric Multi-Objective Optimization Of Cold Plate For Single-Phase Immersion Cooling, Geevarghese Joseph Nattasseriedathil

Mechanical and Aerospace Engineering Theses - Archive

The increasing demand for high performance computing in applications such as Internet of Things, Deep Learning, Big data for crypto-mining, virtual reality, healthcare research on genomic sequencing, cancer treatment etc. has led to the growth of hyper scale datacenters. To meet the cooling energy demands of HPC datacenters efficient cooling technologies must be adopted. Traditional air cooling, direct to chip liquid cooling and immersion are some of those methods. Among all, Liquid cooling is superior compared to various air-cooling methods in terms of energy consumption. Direct on-chip cooling using cold plate technology is one such method used in removing heat …

A Machine Learning Specklegram Wavemeter (Maswave) Based On A Short Section Of Multimode Fiber As The Dispersive Element, Ogbole C. Inalegwu, Rex E. Gerald, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

Wavemeters are very important for precise and accurate measurements of both pulses and continuous-wave optical sources. Conventional wavemeters employ gratings, prisms, and other wavelength-sensitive devices in their design. Here, we report a simple and low-cost wavemeter based on a section of multimode fiber (MMF). The concept is to correlate the multimodal interference pattern (i.e., speckle patterns or specklegrams) at the end face of an MMF with the wavelength of the input light source. Through a series of experiments, specklegrams from the end face of an MMF as captured by a CCD camera (acting as a low-cost interrogation unit) were analyzed …

Simultaneous And Multiplexed Measurement Of Curvature And Strain Based On Optical Fiber Fabry-Perot Interferometric Sensors, Chen Zhu, Hongkun Zheng, Osamah Alsalman, Wassana Naku, Lingmei Ma

Electrical and Computer Engineering Faculty Research & Creative Works

Optical fiber sensors that have a compact size and the capability for multi-parameter sensing are desired in various applications. This article reports a miniaturized optical fiber Fabry-Perot interferometric sensor with a length of hundreds of µm that is able to simultaneously measure variations of curvature, temperature, and strain. The sensor is easy to fabricate, requiring only the fusion splicing of a short section of the silica capillary tube between two single-mode fibers (SMFs). The combined mechanism of the Fabry-Perot interference occurred in the two interfaces between the capillary and the SMFs, and the Anti resonant guidance induced by the capillary …

Automated Segmentation Of Autofluorescence Lifetime Images Using A Convolutional Neural Network, Nicole Hooten

Biomedical Engineering Undergraduate Honors Theses

Chronic wounds affect nearly 1 out of every 50 people in the United States, decreasing quality of life and putting people with potential comorbidities at high risk for obtaining an infection. Wound healing progress in clinical settings is measured by tracking wound size and there are currently no non-invasive, quantitative measurement techniques. Previous studies have proposed nicotinamide adenine dinucleotide (NADH) autofluorescence lifetime (FLIM) imaging of the wound edge as a method to quantify the wound healing process by connecting the role of NADH in cellular metabolism to wound healing stage. However, evaluation of FLIM images is heavily subjective, as a …

Development Of A Computational Model To Investigate Pathways And The Effects Of Treatment In Fanconi Anemia, Sabrina Kellett

Biological Sciences Undergraduate Honors Theses

Fanconi Anemia (FA) is a rare type of anemia that is not easily studied and can have very detrimental effects. This disease compromises the bone marrow, resulting in decreased hemopoiesis. Symptoms of FA also include abnormalities in the brain and spinal cord, incorrect formation of the kidneys, abnormal formation of the heart and lungs, and a dramatically increased risk of developing cancer. FA can be caused by various mutations in any of the 22 genes that encode for proteins involved in what is called the FA DNA repair pathway. In healthy individuals, this pathway specifically repairs interstrand cross-links (ICLs) recognized …

Ranking Highway Transportation Asset Criticality Through Stakeholder Input Using The Analytical Hierarchy Process (Ahp), Kwadwo Amankwah-Nkyi

Graduate Theses and Dissertations

The transportation system is especially vulnerable to natural and human-made disasters which can have effects on mobility, safety, and the economy. This thesis presents a method to rank transportation assets based on their criticality to the transportation system by uniquely gathering stakeholder input on criticality criteria weights. This serves as a typical first step in vulnerability and resilience assessments. Six criteria were used to estimate asset criticality: Annual Average Daily Traffic (AADT), roadway classification, freight output, tourism output, Social Vulnerability Index (SoVI), and redundancy. Then, the criteria are combined via stakeholder input using a weighted ranking scheme called the Analytical …

Automating Lackenby's Method: The Design Of A Set Of Scripts To Execute Lackenby's Method With Mcnaull's Expansion In Rhinoceros 3d, Mara E. Kramer

LSU New Orleans Theses and Dissertations

In vessel design, modifying the design of a preexisting hull is a common practice to save time and labor compared to designing a hull from scratch. This can be achieved either by manually adjusting the hull model in a 3D modeling software or by systematically adjusting certain vessel parameters using an algebraic method. However, these methods are time-intensive and do not fully utilize the capabilities of modern software. To address this issue, this paper presents a set of Rhinoscript and Python scripts that automate part of the hull modification process using Lackenby’s method with McNaull’s expansion. The developed code utilizes …

Hydrological Modeling For The Impact Of Predicted Climate Change And Urbanization: A Case Study Of The Lower Mississippi River Basin, Amelie E. Lagarde

LSU New Orleans Theses and Dissertations

The Mississippi River Basin is the United States’ largest watershed and consists of many subbasins. Each subbasin has hydrological processes including flow rate, evapotranspiration, and groundwater flow. It is important to understand how these processes change through shifts in weather, time, and land use. This study uses the Soil and Water Assessment Tool (SWAT) to predict how changes in temperature, rainfall, and land use can change hydrological processes responses. This study concludes that, for the studied subbasin, a high representative concentration pathway (RCP) will result in lower flow rates and ground water flow as well as higher evapotranspiration by the …

Non-Destructive Means Of Predicting Masonry Prism Strength Using Ultrasonic Pulse Velocity (Upv), Connor J. Barlow

UNLV Theses, Dissertations, Professional Papers, and Capstones

Current ASTM standards call for grouted masonry prisms to be tested for compressive strength at 28-days to ensure compliance with the structural design. In the event of failing tests, the subject samples may require redesign or reconstruction which can pose problems due to ongoing development around and including the prisms between the time of placement and obtaining test results. The purpose of this research is to determine if the use of ultrasonic pulse velocity (UPV) testing can be utilized to determine a correlation between prism composite strength of the masonry prism with ultrasound readings as to provide preliminary means of …

Information-Theoretic Model Diagnostics (Infomod), Armin Esmaeilzadeh

UNLV Theses, Dissertations, Professional Papers, and Capstones

Model validation is a critical step in the development, deployment, and governance of machine learning models. During the validation process, the predictive power of a model is measured on unseen datasets with a variety of metrics such as Accuracy and F1-Scores for classification tasks. Although the most used metrics are easy to implement and understand, they are aggregate measures over all the segments of heterogeneous datasets, and therefore, they do not identify the performance variation of a model among different data segments. The lack of insight into how the model performs over segments of unseen datasets has raised significant challenges …

High-Yield Bioinspired Atmospheric Water Capture Through Hydrogels, Yiwei Gao

UNLV Theses, Dissertations, Professional Papers, and Capstones

Water scarcity is a global issue affecting billions of people, and atmospheric water harvesting (AWH) technology has been identified as a potential solution. However, existing single-material AWH approaches have limited water harvesting yields due to alternated water capture, storage, and release stages, and only function within a high relative humidity range. In my doctoral research project, we developed a bio-inspired, hydrogel-based multi-layer AWH approach that allows for segregated capture, storage, and release stages, and is envisioned to have higher daily water harvesting efficiency even in low-humidity areas. My research began with understanding the relations between hydrogel mechanical stiffness, hydraulic permeability, …

Spectroscopic Studies On Silicon And Chalcopyrite Materials For Solar Energy Applications, Amandee Hua

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this dissertation, silicon-based materials for photovoltaics and chalcopyrite-based materials for photoelectrochemical water splitting are investigated using various spectroscopic and microscopic techniques. Although silicon dominates the photovoltaic market, further improvement can be made by using an alternative low temperature passivation approach. Currently, thermally grown SiO2 passivation is commonly used for silicon solar cells. However, this technique requires high processing temperatures (>800 °C), which increases the thermal budget, potentially decreases the bulk quality of Si, and can lead to difficulties in implementing in production lines. Here, a S-based passivation approach is studied that require lower processing temperatures of ~550 °C. …

Time-Dependent Wetting Behavior Of Hydrogels, Amir Kashani

UNLV Theses, Dissertations, Professional Papers, and Capstones

Hydrogels are 3-D polymers with hygroscopic properties that enable them to absorb and retain large amounts of water. In many applications such as biomedical applications, including drug delivery, wound healing, tissue engineering, biosensors, and contact lenses, agriculture, food and beverage, cosmetics, and environmental, hydrogels also need to maintain a high degree of wetting in order to ensure effective functionality and interaction with surrounding fluids or tissues in desired applications. The combination of wetting and absorptive behavior of hydrogels that are often encountered in biomedical, biological, industrial and the mentioned applications presents a challenging physical problem that is not completely understood. …

Enhanced Iot-Based Electrocardiogram Monitoring System With Deep Learning, Jian Ni

UNLV Theses, Dissertations, Professional Papers, and Capstones

Due to the rapid development of computing and sensing technologies, Internet of Things (IoT)-based cardiac monitoring plays a crucial role in providing patients with cost-efficient solutions for long-term, continuous, and pervasive electrocardiogram (ECG) monitoring outside a hospital setting. In a typical IoT-based ECG monitoring system, ECG signals are picked up by sensors located on the edge, and then uploaded to the remote cloud servers. ECG interpretation is performed for the collected ECGs in the cloud servers and the analysis results can be made instantly available to the patients as well as their healthcare providers.In this dissertation, we first examine the …

Mathematical Modeling: Finite Element Analysis And Computations Arising In Fluid Dynamics And Biological Applications, Jorge Reyes

UNLV Theses, Dissertations, Professional Papers, and Capstones

It is often the case when attempting to capture real word phenomena that the resulting mathematical model is too difficult and even not feasible to be solved analytically. As a result, a computational approach is required and there exists many different methods to numerically solve models described by systems of partial differential equations. The Finite Element Method is one of them and it was pursued herein.This dissertation focuses on the finite element analysis and corresponding numerical computations of several different models. The first part consists of a study on two different fluid flow models: the main governing model of fluid …

A One-Dimensional Analysis Of A Microbial Fuel Cell For Efficient Acetate Removal And Power Density Output, David Rouhani

UNLV Theses, Dissertations, Professional Papers, and Capstones

Microbial fuel cells (MFCs) are electrochemical devices that utilize microorganisms to convert organic matter into electrical energy. MFCs have been discussed to have potential application for sustainable wastewater treatment due to their ability to generate electricity while simultaneously treating contaminated water. To optimize MFC performance, numerical models can be used to understand the complex electrochemical and biological processes occurring in the system. In this study, a numerical model was developed to simulate the performance of MFCs under varying operating conditions and to investigate the performance of a MFC for treating wastewater fuel. More specifically, the MFC was modeled to oxidize …

Development Of An Automated Gpib System For Characterization Of Sige Avalanche Photodiodes, David A. Santiago

UNLV Theses, Dissertations, Professional Papers, and Capstones

Photon counting is a technique in many modern technologies such as medical imaging and LiDAR systems. Photon counting is needed in many aspects of the development process for these technologies from photodetector characterization to operation of the finished product. This thesis will serve to solve the challenge of quantifying photodetector performance using automating test equipment with known software packages such as MATLAB to be able tocharacterize photodetectors in an efficient manner. A custom MATLAB program has been developed to interface with various instrumentation using a General-Purpose Interface Bus (GPIB) and a Prologix GPIB-USB controller that will be able to send …

Monitoring And Classification Of Tissue Perfusion Through The Combined Use Of Thermal, Rgb, And Laser Speckle Contrast Imaging, Ivan Soto

UNLV Theses, Dissertations, Professional Papers, and Capstones

In cooperation with the UNLV School of Medicine, this thesis is part of a bigger project aimed at developing a post-op surgery device for the constant unattended monitoring of a patient’s tissue. This device is intended to monitor areas of surgical sites and detect any complications without the need for continuous supervision by medical professionals. One such complication includes inadequate tissue perfusion, or a lack of blood flow reaching a patient’s tissue. The role of this thesis is to fit a convolutional neural network model to the available data gathered from voluntary participants and attempt to classify the data as …

Simulating Condensation In The Theory Of Classical Nucleation, David Vallet

UNLV Theses, Dissertations, Professional Papers, and Capstones

The scope of this thesis is to numerically investigate condensation that occurs in transonic and supersonic flows. Condensation shocks are a phenomenon that occurs within converging-diverging nozzles. There are many applications forconverging-diverging nozzles, such as thermovapour compressors (TVC), which are largely used for desalination. As water resources become more precious within the western United States there is a need to develop cost effective solutions for cleaning water. Steam generator power stations are another application where enhanced simulations and accuracy of design could improve efficiency and save on carbon emissions. Traditionally, numerical designs of transonic flows have been conducted with either …

Analysis And Application Of Finite Element And High-Order Finite Difference Methods For Maxwell’S Equations In Complex Media, Li Zhu

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Perfectly Matched Layer (PML) technique is an effective tool introduced by B´erenger [13] to reduce the unbounded wave propagation problem to a bounded domain problem. This dissertation focuses on two different PML models and their applications to wave propagation problems with Maxwell’s equation in complex media. We investigate these models using two popular numerical methods: the Finite Difference Method (FDM) in Chapters 2 and 3, and the Finite Element Method (FEM) in Chapters 4 and 5.In Chapter 2, we focus on analyzing the stability of a PML developed by B’ecache et al. [10] for simulating wave propagation in the …

Preparing Homogenous Composites Of Collagen And Cellulose Nanocrystals For Tissue Engineering Research, Zachary Stanley

Biological and Agricultural Engineering Undergraduate Honors Theses

Advancements in medicine and our understanding of stem cells have led to a greater emphasis on further developing research focused on tissue engineering. This research has led to the rise of both two-dimensional and three-dimensional scaffolds that can be utilized to repair bone, skin, vascular, and potentially even nervous tissue. One of the prominent compounds used in modern scaffolds is collagen-based hydrogels due to their low antigenicity and ability to provide structure to cells. There is potential to further improve upon this three-dimensional scaffold by incorporating cellulose nanocrystals (CNCs) into a composite hydrogel with collagen. The addition would increase the …

Analyzing Energy Use From Arkansas Public School Buildings, Oscar Morton

Biological and Agricultural Engineering Undergraduate Honors Theses

Energy is a key global resource in society and greenhouse gas (GHG) emissions related to the consumption of energy have detrimental effects on the planet. With energy consumption increasing, exponential population growth, and diminishing natural resources necessary for energy production, the relevance of energy efficiency is dramatically increasing. In this project, I analyzed energy usage data from a set of public school buildings from one school district in northwest Arkansas from 2018, before targeted energy efficiency practices were implemented, through 2022 to see if energy usage changed over this short period. The objectives of analyzing energy data were to determine …

Analysis And Implementation Of A New High-Buck Dc-Dc Converter With Interleaved Output Inductors And Soft Switching Capability, Sajad Ghabeli Sani, Mohamad Reza Banaei, Seyed Hossein Hosseini

Turkish Journal of Electrical Engineering and Computer Sciences

This paper proposes an innovative structure for DC-DC converters with high buck gain by using a lower number of elements. The converter provides highly efficient output power and an extended output voltage range. In addition, the distribution of output current between two inductors and the soft-switching capability of the power switches have made the converter suitable for applications that require high output current. All power switches accomplish the ZVZCS (zero-voltage and zero-current switching) condition with the aid of a small auxiliary inductor (Lx), which charges and discharges parallel capacitors of main switches to provide soft-switching conditions. Thus, the switching losses …

An Efficient Deep Learning Architecture For Turkish Lira Recognition And Counterfeit Detection, Burak İyi̇kesi̇ci̇, Ergun Erçelebi̇

Turkish Journal of Electrical Engineering and Computer Sciences

Banknote counterfeiting is a common practice worldwide. Due to the recent developments in technology, banknote imitation has become easier than before. There are different kinds of algorithms developed for the detection of counterfeit banknotes for different countries in the literature. The earlier algorithms utilized classical image processing techniques where the implementations of machine learning and deep learning algorithms appeared with the developments in the artificial intelligence field as well as the computer hardware. In this study, a novel convolutional neural networks-based deep learning algorithm has been developed that detects counterfeit Turkish Lira banknotes and their denominations using the banknote images …

Closed-Loop, Recyclable Plastics From Ethyl Cyanoacrylate, Allison Joy Christy

Boise State University Theses and Dissertations

Ethyl cyanoacrylate, commonly known as super glue, has held a prominent role as an adhesive for decades due to its propensity to rapidly polymerize into poly(ethyl cyanoacrylate) (PECA) under ambient conditions. Ethyl cyanoacrylate monomers and their resulting PECA polymers are bio-friendly, which has allowed them to be used as medical adhesives and to be applied to drug delivery systems. However, PECA has not been used as a plastic material due to the perceived difficulty of handling the ethyl cyanoacrylate monomer. Here, we present a novel PECA plastic that displays thermal stability and tensile strength values that are comparable to atactic …

Protecting The Infrastructure Of Michigan: Analyzing And Understanding Internet Infrastructure, Samuel Blaser, Travis Munyer, Damian Ramirez, Lester Juarez, Jackson Servant

Theses/Capstones/Creative Projects

The Michigan Army National Guard DCOE is hoping to increase their understanding of the physical, electrical, protocol, and logical topography of internet service. In order to understand the infrastructure of the internet, information must be collected on its pieces. By studying, describing, and illustrating the infrastructure of the global internet we can develop hardening tactics, improve user training, and develop contingency plans in the case of an attack. The research is focused on where data lives, locating data centers in the region, identifying global infrastructure and who owns it, and potential for hardening. An interactive map has been created in …