Engineering Commons^™

Discourse Analysis In Engineering: Investigating Patterns In Brainstorming Conversations, Aimee Chiem

Master's Theses

Brainstorming is a critical part of the engineering design process and can have a significant impact on the outcomes of the overall project. While research has studied the outcomes of brainstorming and the ideas that teams generate, the role that language and conversation play in these activities is still relatively underexplored. Observing the different ways people use specific types of discourse can reveal how conversations can affect brainstorming itself. To that end, this research aims to answer the following questions:

1) What are the different kinds of discursive moves that students make during engineering brainstorming activities?

2) What patterns or …

A Numerical Modeling Analysis Of The San Francisco Bay And Sacramento-San Joaquin Delta: Riverine, Tidal, And Wind Processes, Drake A. Abrahamsson

Master's Theses

The primary motivation of this study is to analyze the 1D-2DH hydrodynamic model of the San Francisco Bay and Sacramento-San Joaquin Delta (SFBD) outlined in Nederhoff et al. (2021). I compared model water level data to 70 tidal records from the National Oceanic and Atmospheric Association (NOAA), the United States Geological Survey (USGS), the California Data Exchange Center (CDEC), and from local municipalities throughout the Bay Area to investigate how the model captures water levels and tidal constituent amplitudes. While the Nederhoff et al (2017) model analyzed an extended time period from 1950-2019, I analyzed M2 amplitude and tidal water …

Launch Vibration Attenuation For In-Space Assembly Cargo, Jered Bell

Master's Theses

This thesis investigates the implementation of a passive isolator with a pressurized air cushion for spacecraft payloads in mission architectures implementing in-space assembly technologies. A pressurized air bed capable of briefly surviving the space environment for cargo delivery was prototyped and experimentally evaluated for launch vehicle vibration dynamics resulting in a 72%, 93%, and 88% reduction in experienced GRMS loads for the X-Axis, Y-Axis, and Z-Axis, respectively. A preliminary Total Mass Loss evaluation of the Low-Density Polyethylene Film utilized for the air bed resulted in a mass loss of 0.7%, indicating that commercial off-the-shelf films might require minimal modification for …

Fabrication Of Alumina Membranes From Uv Resin– Alumina Particle Slurries, Dominique Henry Porcincula

Master's Theses

Ceramics membranes are made in a wide variety of different techniques using a wide variety of different materials. However, many of the common techniques utilize a slurry of ceramic particles, additives, and either organic solvent or water that is shaped into a membrane, left to dry, and then sintered together. Drying is a time consuming process, often requiring several hours for the liquid medium to evaporate. Defect formation caused by development of partial pressures across the drying membrane, including cracks and warpage, also typically occurs during the drying process. To address this, slurries of ceramic particles made with a low …

Wettability Dynamics Of Kerogen: Insights From Molecular Dynamics Simulations On Thermal Maturity And Reservoir Temperature Impact, Wei Liang, Xin Chen, Rajat Sharma

Publications and Research

This comprehensive review explores the multifaceted role of kerogen in organic-rich mudrock reservoirs, focusing on its impact on porosity, hydrocarbon storage, and transport pathways. The dominance of kerogen-hosted pores is underscored as a critical determinant of reservoir dynamics, with an emphasis on the wettability of kerogen as a pivotal parameter. The intricate relationship between kerogen wettability and petrophysical properties, including water saturation and electromagnetic characteristics, is elucidated, emphasizing the broader implications for reservoir management and hydrocarbon recovery.

The study delves into the thermal maturation of kerogen, unraveling the chemical evolution from hydrogen-rich organic matter to hydrogen-poor residual carbon. The Van …

Advanced Jet Impingement Cooling For Power Electronics, Reece Whitt

Graduate Theses and Dissertations

Convective heat transfer by jet impingement cooling offers a suitable solution for high heat flux applications. Compared to techniques that rely on bulk conduction in series with convection, direct liquid impingement reduces the thermal resistance between power device hot spots and the coolant. Using additive manufacturing processes, location specific jets can be integrated into high voltage power electronics systems. Custom manifolds can be designed to reduce pressure drop, while simultaneously fine-tuning the thermal management efficiency. Although capable of highly efficient cooling, static impingement devices must be designed for the worst-case cooling requirements for a transient power profile, possibly resulting in …

Accelerated Testing Of Solder Spheres Under Combined Temperature, Current, And Shear Stresses To Estimate Reliability, Collin Ruby

Graduate Theses and Dissertations

With the densification of power electronics in the pursuit of decreased size and weight and increased efficiency, the need to investigate the properties of solder in packages with higher working temperatures and power densities is becoming apparent. Many research groups have conducted accelerated testing using methods such as thermal aging, shear or tensile stress tests, or electromigration tests, but relatively little research exists that considers the impact of several stresses in a combined study. This work aims to produce a novel method for estimating the lifetime of SAC305 solder joints under a combined stress scenario, which more accurately depicts the …

Federated Active Learning For Network Intrusion Detection, Matthew D. R. Sauer

Theses and Dissertations

This thesis addresses challenges with detecting attacks on computer networks within a Federated Learning (FL) framework, when labeled instances are few. We explore the integration of active learning (AL) and semi-supervised learning (SSL). AL efficiently uses data that would otherwise be wasted or require substantial time for labeling. SSL provides capacity to train models that have a limited amount of labeled data, by utilizing additional unlabeled data that is available. We show how FL combined with AL or SSL can realize a detection system that adapts and trains quickly to new networks, reducing the total amount of data labeling needed. …

Marss: Multi-Agent Reinforcement Learning For Satellite Swarms, Nicholas J. Yielding

Theses and Dissertations

Multi-agent systems and swarms in spacecraft formation flying are of ever-increasing importance in a contested space environment—use of multiple spacecraft to contribute to a cooperative mission potentially increases positive outcomes on orbit, while autonomy becomes an ever more important requirement to reduce reaction time in dynamic situations and lower the burden on space operators. This research explores difficult swarm Guidance Navigation and Control (GNC) scenarios using Deep Reinforcement Learning (DRL). DRL polices are trained to provide guidance inputs to agents in multi-agent swarm environments for completing complex, teamwork focused objectives in geosynchronous orbit. An example scenario is explored for a …

An Improved Saliency Map With Trustworthiness For Localizing Abnormalities In Medical Imaging, Nolan C. Skelly

Theses and Dissertations

Saliency maps are a widely used methodology to make deep learning models more interpretable. They provide post-hoc explanations through identification of the most pertinent areas of an input medical image. These techniques have been assessed based on 1) localization utility, 2) sensitivity to model weight randomization, 3) repeatability, and 4) reproducibility. Ten saliency map techniques will be tested, Grad, Smooth Grad, Integrated Gradients, Smooth Integrated Gradients, XRAI, Grad-CAM, Guided Backpropagation, Guided GradCAM, GradCAM++, and ScoreCAM. The neural networks used to predict and read medical information require a reliable solution to provide medical practitioners intelligible results. Using the information of two, …

Nanobubble Technology For The Removal Of Mib And Geosmin From Drinking Water, Meryem Soyluoglu

All Dissertations

The presence of taste and odor (T&O) compounds in drinking water has been historically a major challenge for water utilities. They are difficult to remove using conventional water treatment processes, a combination of coagulation, flocculation, sedimentation, filtration, and chlorination. However, activated carbon (AC) adsorption, advanced oxidation processes, and biofiltration can be effective. The seasonal nature of T&O events makes it difficult to justify installing dedicated treatment technologies. Additionally, incorporating these technologies into existing water treatment plants can be expensive and require significant upgrades. Therefore, water utilities are always interested in exploring new approaches to minimize the occurrence and removal of …

Stochastic Modeling Of Decarbonizing Strategy, Policy, And Market-Induced Incentives For The Us Electricity Sector, Jessica W.A. Azure, Samuel Frimpong, Mahelet G. Fikru

Mining Engineering Faculty Research & Creative Works

In line with the global pursuit of achieving net-zero carbon emissions, integrating carbon capture and storage (CCS) and renewable energy (RE) technologies is important in power production. This study evaluates the profitability of CCS and RE technologies as alternative ways of achieving climate change goals. While past research focused on costs, technological advancements, and capture methods, there is a need for more studies on assessing the financial feasibility of these climate change solutions under uncertain conditions, alongside specific performance goals and strategies to entice power producers. Using a comprehensive framework featuring deterministic and stochastic modeling approaches, this research explores the …

Advancing Winter Weather Adas: Tire Track Identification And Road Snow Coverage Estimation Using Deep Learning And Sensor Integration, Parth Kadav

Masters Theses

No abstract provided.

Deep Learning Frameworks For Accelerated Magnetic Resonance Image Reconstruction Without Ground Truths, Ibsa Kumara Jalata

Graduate Theses and Dissertations

Magnetic Resonance Imaging (MRI) is typically a slow process because of its sequential data acquisition. To speed up this process, MR acquisition is often accelerated by undersampling k-space signals and solving an ill-posed problem through a constrained optimization process. Image reconstruction from under-sampled data is posed as an inverse problem in traditional model-based learning paradigms. While traditional methods use image priors as constraints, modern deep learning methods use supervised learning with ground truth images to learn image features and priors. However, in some cases, ground truth images are not available, making supervised learning impractical. Recent data-centric learning frameworks such as …

Ism-Band Energy Harvesting Wireless Sensor Node, Fnu Naveed

Graduate Theses and Dissertations

In recent years, the interest in remote wireless sensor networks has grown significantly, particularly with the rapid advancements in Internet of Things (IoT) technology. These networks find diverse applications, from inventory tracking to environmental monitoring. In remote areas where grid access is unavailable, wireless sensors are commonly powered by batteries, which imposes a constraint on their lifespan. However, with the emergence of wireless energy harvesting technologies, there is a transformative potential in addressing the power challenges faced by these sensors. By harnessing energy from the surrounding environment, such as solar, thermal, vibrational, or RF sources, these sensors can potentially operate …

Characterization Of Highly Doped N-Type And P-Type Silicon Carbide Ohmic Contacts, Tanner Rice

Graduate Theses and Dissertations

Silicon Carbide (SiC) is a rather new material that possesses unparalleled properties when compared to Silicon. Due to its larger band gap alongside other thermal properties, SiC can survive in hotter, more radiation intensive environments, whether that be within the crust of the earth or in the reaches of space. As a desirable semiconductor for these applications, CMOS is an especially important device due to its low power consumption. However, creating a good contact between the metal and semiconductor optimally requires two different metals for the n -type and the p-type semiconductor. This greatly increases the processing time, as separate …

Performance Of Co2-Cured Alkali-Activated Slag Pastes During Curing And Exposure, Yubin Jun, Seong Ho Han, Jae Hong Kim

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study investigated the efficiency of CO₂ curing in blast-furnace slag pastes activated with three concentrations of KOH solution (3, 4, and 5 M). The CO₂ curing was applied into the alkali-activated slag paste for 3 days. The CO₂-cured pastes were subjected to subsequent curing in a water bath or exposed to seawater. The mechanical properties and characteristics of the reaction products were compared. Full strength can be obtained within 3 days of the early CO₂ curing. The strength remained almost constant regardless of the activator concentration. The CO₂-cured samples produced more CaCO …

Amine-Functionalized Lignin-Based Ionomer Nanocomposites For Redox Flow Batteries, Joshua Wilder

All Theses

As the development of energy storage technologies for renewable energy sources continues to garner attention, vanadium redox flow batteries (VRFBs) have emerged as promising source for grid-scale energy storage. A major component of the VRFB is the ion exchange membrane (IEM), as it serves to physically separate the two liquid electrolytes and also directly impacts the battery’s capacity, efficiency, and cost. The current industry standard IEM, Nafion™, not only accounts for a large portion of the cost of the VRFB but also suffers from poor proton selectivity. Herein, we have synthesized sulfonated poly(ether ether ketone) (SPEEK) composite membranes containing amine …

Effect Of Latex Modified Concrete Overlays With Reduced Surface Preparation On The Load Distribution And Flexural Strength Of Channel Girders, Samuel Dodd

All Theses

This thesis investigates the use of a Latex Modified Concrete (LMC) overlay to increase the strength of prestressed channel girders and enhance their ability to distribute load. The research conducted in this thesis involved material testing of several different LMC mixes and flexural testing of an LMC overlay and girder system. The material testing was used to determine a reasonable LMC mix design and surface preparation method to be used for the overlay. Based on material testing it was concluded that a rapid-set mix and pressure washing of the girder surfaces were a reasonable mix design and surface preparation for …

Radiation Exposure Calibration Of The Al2o3:C With Radium-226 And Cesium-137 Using The Osl Method, Selma Tepeli Aydin

All Theses

Optically stimulated luminescence (OSL) dosimetry was utilized to calibrate Al₂O₃:C powder dosimeters, available commercially as the nanoDot® from Landauer Inc., and compare the dosimeter response to radium-226 (²²⁶Ra) and cesium-137 (¹³⁷Cs). The signal from the OSL was quantified using a microSTARii^® OSL reader also produced by Landauer Inc. Dose-response curves were developed for ²²⁶Ra and ¹³⁷Cs experiments (5 dosimeters each) at thirteen absorbed doses. Individual dosimeter response was tracked by serial number. Linear regression analysis was performed to determine if there were significant differences between the intercepts of the …

The Effects Of Silica Sand Particle Size On Drying Using A Vertical Fluid Bed Dryer, Aysun ŞengüL, Soner Celen, Ayşen Haksever

The Philippine Agricultural Scientist

The experimental and theoretical relationships of silica sand particle size and drying was compared to predict the minimum fluidization rate in drying at 9.57% moisture. The drying temperature (90°C, 120°C, and 150°C) and particle size (274 ± 0.5 μm, 563 ± 0.5 μm, and 910 ± 0.5 μm) parameters were studied as factors influencing the drying process in the experiment. Upon comparing all the test results, it was found that moisture loss accelerated as drying temperature of the silica sand samples increased. On the other hand, the minimum fluidization rate was found to have varied directly with particle size, in …

Additive Manufacturing Of Composites For Sensing And Harsh Environments Application, Md Sahid Hassan

Open Access Theses & Dissertations

Composite materials are made by combining two or more materials, such as fibers and resins to create a material system that has improved mechanical and physical properties compared to its individual components. The use of 3D printing technology in composite manufacturing allows for the creation of complex and custom shapes with precise control over the placement of the materials. This makes it possible to create composite parts with enhanced performance characteristics and reduced weight. The work presented in this dissertation lies in the design and development of highly flexible impact propagation sensor through material extrusion 3D printing technique. By using …

Niobate Nanosheet Catalysts For Cationic Dye Intercalation And Solar-Driven Water Photolysis, Cassandra Idona Monárrez-Grendahl

Open Access Theses & Dissertations

With the goal of creating efficient visible light photocatalysts for water photolysis, in this work we are exploring the synthesis of new porous oxide materials derived from potassium triniobate (KNb3O8) and titanium niobium oxide (KTiNbO5), which are layered wide band gap semiconductors. Generating hydrogen via direct water photolysis holds promise as a way to lower the cost of hydrogen gas production so it can be used as a renewable and clean alternative fuel. My group has demonstrated that layered semiconductor materials have the potential to enable the synthesis of new types of photocatalyst composites with customizable characteristics. In this work, …

Bitcoin's Technical Foundation And Its Potential For A Decentralized And Environmentally Friendly Future, Iqtiar Md Siddique

Open Access Theses & Dissertations

This research examines a systematic analysis of Bitcoin, employing a Coefficient of Variation (CV) approach to gauge its degree of decentralization. Bitcoin, an innovative decentralized digital currency, has received much attention for its potential to revolutionize traditional financial systems. This study employs the Coefficient of Variation (CV) to acquire insights into the wealth distribution and concentration among Bitcoin users. This research demonstrates how decentralized the network of Bitcoin is. The methodology uses real data on Bitcoin addresses and their holdings to compute the Coefficient of Variation (CV). This approach provides valuable insights into the ongoing discourse surrounding Bitcoin's decentralization, offering …

Towards A Spaceworthy Cots Graphics Processing Unit: Hardware Performance Counter Based Symptomatic Fault Detection, Antonio E. Teijeiro

Open Access Theses & Dissertations

Ionizing radiation remains an obstacle to bringing graphics processing units (GPU) to space. Since radiation-hardened GPU chips are technically infeasible at the moment, an emphasis has been placed on the adaptation of commercial-off-the-shelf (COTS) GPUs to the space domain. At present, GPU error detection methods require redundant computation. This thesis work explores the utilization of hardware performance counters, special registers useful for monitoring internal GPU hardware events, for symptom-based, lightweight error detection. Hardware performance counters are successfully utilized for the detection of anomalous single event upsets in the L0 instruction cache, the load store unit, the arithmetic and logic unit, …

A Comprehensive Review On Metal Oxide-Nanocellulose Composites In Sustainable Active And Intelligent Food Packaging, Kalpani Y. Perera, Amit Jaiswal, Swarma Jaiswal, Dileswar Pradhan

Articles

The aim of this article is to provide an overview of the potential advantages and drawbacks of nanocellulose and metal oxide-based composites in food packaging. These materials offer improved mechanical and barrier properties, as well as antioxidant and antimicrobial benefits that extend the shelf life of food products. Nanocomposite structures protect food from various physiological factors and immobilize enzymes, while metal oxide nanoparticles provide antibacterial effects against Gram-positive and Gram-negative bacteria. However, there are concerns regarding the safety of nanoparticles and their potential migration into packaged food during processing and storage. This article explores these issues and highlights the need …

Co2 Storage Capacity And Injectivity Of Stacked Carbonates Of The Pennsylvanian And Permian In Western Nebraska, Lateef Lawal

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

Geological carbon storage (GCS) is a critical aspect of carbon capture and storage (CCS) in which captured CO₂ from power plants and industrial processes is injected and stored securely underground. Potential subsurface rock formations include saline aquifers, depleted oil and gas reservoirs, unmineable coal seams and volcanic rocks. GCS technology has been proven in the United States and many other parts of the world as a net-zero carbon emission strategy to mitigate the current climate crisis of our planet. Unlike other states such as Wyoming, GCS projects are still in the early phases in Nebraska. The goal of this …

Design Of Human Serum Albumin And Adenovirus Conjugation Via Catcher/Tag Molecular Glue, Peijie Zhao

McKelvey School of Engineering Graduate Student Theses & Dissertations

Adenovirus (Ad) has been the ideal cargo delivery mechanism, and its moderate immunological response makes it ideal for in vivo gene therapies since its discovery in 1953. However, the robust immunogenicity of the Ad capsid and low vaccine absorption via mucous membranes and epithelium put a limit on the process of developing intranasal vaccines. Efforts are being made to enhance the effectiveness of Ad vectors and numerous studies have demonstrated the remarkable capacity of human serum albumin (HSA) to extend plasma half-life and facilitate targeted intranasal delivery. In this study, we devised an innovative method for employing the Catcher/Tag molecular …

Determining The Effects Of Glycocalyx Modifications On The Electrophysical Properties Of Human Mesenchymal Stem Cells, Rominna E. Valentine Ico

Electronic Theses, Projects, and Dissertations

Human mesenchymal stem cells (hMSCs) have gained popularity in clinical trials due to their multipotent differentiation characteristics, ability to secrete bioactive molecules, migrate into diseased or damaged tissues, and their immunosuppressive properties. HMSC cultures are heterogeneous, containing stem cells, partially differentiated progenitor cells, and fully differentiated cells. One of the major challenges with hMSCs therapeutic potential is the inability to select specific cell subpopulations due to an insufficient number of biomarkers. Often the biomarkers used, like those for fluorescence-activated cell sorting, are not sufficient to define hMSCs because they overlap with other cell types. Consequently, there is a need to …

Nonlinear Finite Element Model For Functionally Graded Porous Circular/Annular Micro-Plates Under Thermal And Mechanical Load, Enrique Nava Munoz

Masters Theses

A nonlinear finite element model for micro circular/annular plates under thermal and mechanical loading is developed using a third order shear deformation theory. In the kinematic assumptions, the change of plate thickness is allowed and no transverse shear strains are considered on the top and bottom surfaces. A power-law distribution is utilized to account for variations of two constituents through the thickness of the plate. Three different types of porosity distributions are considered. The strain gradient effect in micro scale structures is considered using the modified couple stress theory. The dynamic version of the principle of virtual displacements is used …