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2025

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Articles 8131 - 8160 of 8577

Full-Text Articles in Engineering

Simulation-Enhanced Bayesian Optimization Of System Designs Using Hybrid Physical And Computer Experiments, Luke Kim, Kelly Sullivan, Haitao Liao, Ed Pohl Jan 2025

Simulation-Enhanced Bayesian Optimization Of System Designs Using Hybrid Physical And Computer Experiments, Luke Kim, Kelly Sullivan, Haitao Liao, Ed Pohl

2025 Research Poster Competition

We consider the problem of learning and optimizing the performance of a system by conducting a limited number of physical and digital experiments within a design space. Physical experiments are assumed to be unbiased but costly, while digital experiments (e.g., simulations) are less expensive but may introduce bias due to the limitations of the simulation model. This problem is relevant in many fields, such as optimizing engineered systems where performance (e.g., mechanical properties and reliability) depends on various design variables and external/internal factors. Without digital experiments, optimizing the system’s performance amounts to evaluating a noisy and expensive-to-assess black-box function, a …


A Time-Domain Boundary Integral Equation For Moving Acoustic Sources In Uniform Flow And Its Solution By An Advanced Time Propagation Approach, Fang Q. Hu, Douglas M. Nark Jan 2025

A Time-Domain Boundary Integral Equation For Moving Acoustic Sources In Uniform Flow And Its Solution By An Advanced Time Propagation Approach, Fang Q. Hu, Douglas M. Nark

Mathematics & Statistics Faculty Publications

This paper presents a time-domain boundary integral equation (TDBIE) formulation for predicting acoustic scattering from moving sources in a uniform mean flow. This work is motivated by the increasing need for accurate aeroacoustic modeling of modern aircraft configurations, including VTOL and eVTOL systems with rotating components. A key challenge in time-domain scattering simulations with moving sources is the determination of retarded time for a given observer time, which involves solving an implicit equation at each time step. This can be computationally costly, particularly for numerical solution of the TDBIE where every surface element on the scattering body acts as an …


A Bridge Too Low, John Adam Jan 2025

A Bridge Too Low, John Adam

Mathematics & Statistics Faculty Publications

The article "A bridge too low" in the Physics Teacher journal discusses a low bridge near the River Greta in Keswick, England, with an arch shaped like a semiellipse. It presents questions about the maximum height a person of a certain height can walk under the bridge without hitting their head, the cross-sectional area of the arch, its eccentricity, and perimeter. The article also mentions the approximation by Indian mathematician Srinivasa Ramanujan for the perimeter of an ellipse and invites readers to find the answers online.


Globus Pallidus Internus Dynamics During Freezing Of Gait, Nicholas Druck, Dean J. Krusienski, Josephine Wallner Jan 2025

Globus Pallidus Internus Dynamics During Freezing Of Gait, Nicholas Druck, Dean J. Krusienski, Josephine Wallner

Graduate Research Posters

Background: Parkinson’s disease (PD) is a progressive neurodegenerative disorder affecting ~1 in 1000 individuals over age 45. Freezing of Gait (FOG), a debilitating symptom in late-stage PD, affects up to 63% of patients and contributes to falls and reduced quality of life. While deep brain stimulation (DBS) of the subthalamic nucleus (STN) helps some symptoms, FOG remains difficult to treat. Given the complexity of basal ganglia circuitry, the role of related basal ganglia nuclei, such as the Globus Pallidus internus (GPi), in FOG deserves further investigation.

Methods: Five PD patients with FOG, implanted with Medtronic Percept DBS systems …


Predicting Complex Di-Alkylation Kinetics Using Machine Learning, Colin Bailey, Thomas Roper Jan 2025

Predicting Complex Di-Alkylation Kinetics Using Machine Learning, Colin Bailey, Thomas Roper

Graduate Research Posters

Background: Predicting reaction kinetics for complex chemical systems often presents significant challenges due to intricate reaction pathways, multiple product formations, and competing side reactions. Additionally, the transient nature of reaction intermediates and limited experimental data complicate efforts to capture system dynamics accurately. These complexities necessitate advanced modeling approaches and precise experimental techniques to reliably describe and predict chemical behavior.

Methods: This work investigates the kinetics of di-alkylation of 4-Hydroxybenzoic Acid (4-HBA) using multiple machine learning algorithms, including Random Forest Regression, Gradient Boosting, Lasso, Ridge, and XGBoost. By leveraging reaction conditions, such as temperature, sulfuric acid equivalents, and initial concentrations of …


Dc To Ac Voltage Source Converter Control System, Mohummad Tark Elgassier, Jordan M. Reichhardt, Brayden Richard Young Jan 2025

Dc To Ac Voltage Source Converter Control System, Mohummad Tark Elgassier, Jordan M. Reichhardt, Brayden Richard Young

Electrical Engineering

The Voltage Source Converter Control System integrates a control system for a 2-phase half-bridge voltage source converter (VSC) utilizing a TMS320F2837xD Dual-Core Real-Time Microcontroller. VSCs are critical for the integration of power production into the power grid. They allow for accurate control over DC-AC energy conversion. Additionally with the improvement of renewable energies VSCs play a critical role in controlling the flow of these environmentally controlled and more unpredictable sources of energy. The control system regulates the output current and voltage, regulates switching patterns, and maintains power stability under varying loads. Within the control system Digital control systems, PWM generation, …


Cryogenic Gas Cell For Infrared Space Instrumentation, Trent Newswander, Scott Bailey, Mark Hervig, Phillip Scott, Ryan Luder, Mike Watson, Mike Oksness, Cody Secrist, Zack Hatfield Jan 2025

Cryogenic Gas Cell For Infrared Space Instrumentation, Trent Newswander, Scott Bailey, Mark Hervig, Phillip Scott, Ryan Luder, Mike Watson, Mike Oksness, Cody Secrist, Zack Hatfield

Space Dynamics Laboratory Publications

• NASA’s Dynamical Neutral Atmosphere-Ionosphere Coupling (DYNAMIC) mission aims to characterize the energy transfer between the ionosphere, thermosphere, and mesosphere

– Identified as a high priority solar terrestrial probe mission in two decadal surveys

– Led by Virginia Polytechnic Institute and State University

• The Doppler Wind and Temperature Sounder (DWTS) is being developed for flight on the DYNAMIC satellite

– Will provide the first comprehensive global dataset of winds and temperature in the mesosphere and thermosphere (40–250 km altitude)

– Designed and built by Space Dynamics Lab (SDL)

• DWTS observes the Doppler shift of atmospheric NO and 13 …


Design And Characterization Of The Icon Fuv Ccd Cameras, Erik Syrstad, Brian Thompson, Robert Burt, Mitch Whiteley, James Champagne, Pedro Sevilla Jan 2025

Design And Characterization Of The Icon Fuv Ccd Cameras, Erik Syrstad, Brian Thompson, Robert Burt, Mitch Whiteley, James Champagne, Pedro Sevilla

Space Dynamics Laboratory Publications

Outline

  • FUV Overview
  • Key Requirements
  • Camera Design
  • Assembly and Integration
  • UV Performance Characterization


Atms And Cris Geolocation, Mark Esplin, Kris Robinson, Ben Esplin, Nephi Grant, Deron Scott, Likun Wang Jan 2025

Atms And Cris Geolocation, Mark Esplin, Kris Robinson, Ben Esplin, Nephi Grant, Deron Scott, Likun Wang

Space Dynamics Laboratory Publications

Contents

  • Summary of Suomi NPP sensors CrIS, ATMS, and VIIRS 
  • Geolocation methods 
  • Software optimization
  • CrIS geolocation results
  • ATMS geolocation results
  • Conclusions


Comparison Of Co-Located Mid-Latitude Sporadic E And Simone Wind Observations, Ivana Molina, Kenneth Obenberger, Jorge Chau, Matthias Clahsen Jan 2025

Comparison Of Co-Located Mid-Latitude Sporadic E And Simone Wind Observations, Ivana Molina, Kenneth Obenberger, Jorge Chau, Matthias Clahsen

Space Dynamics Laboratory Publications

Sporadic E are localized layers of enhanced metallic ionization that form in the E region of the ionosphere (Mathews, 1998). They are usually observed between 95 and 120 km altitude with a thickness in altitude ranging from ~100 m to a few kilometers. Studying these layers is important, as their characteristics and variability impact the propagation of HF radio waves. At mid-latitudes, the generation of sporadic E is most often explained by the wind shear theory, where these layers form due to the convergence of ions generated by vertical shears in the horizontal components of the neutral wind. The primary …


Reset Reengineering, System Engineering & Test Services, David Brenchley, Matt Dayley, Al Dubovik Jan 2025

Reset Reengineering, System Engineering & Test Services, David Brenchley, Matt Dayley, Al Dubovik

Space Dynamics Laboratory Publications

Sustainment of aging Department of Defense systems presents significant challenges. The Space Dynamics Laboratory (SDL) offers a cost-effective partnership to help the military maintain or enhance the capability of legacy systems. SDL provides trusted reengineering, system engineering, and test (RESET) services, providing Government-owned technical solutions that help the military:


Calibration And Systems Engineering Collaboration, John Wilson Jan 2025

Calibration And Systems Engineering Collaboration, John Wilson

Space Dynamics Laboratory Publications

Systems engineering and calibration engineering are critical to the efficient development, production, and operation of complex systems. Systems engineering provides the framework for the system lifecycle, ensuring stakeholder needs are met through integrated solutions. Calibration engineering ensures the accuracy, reliability, traceability of measurement, and compliance with standards. Coordination between system engineering and calibration ensures that instrumentation, control systems, and system performance are enabled. As the lifecycle coordinator, systems engineering relies on calibration engineers to reduce risks, optimize development, and ensure operational success.

However, the relationship between these disciplines is often poorly coordinated, as noted in tabletop discussions at CalCon 2024. …


Laser-Induced Graphene For Early Disease Detection: A Review, Sri Ramulu Torati, Gymama Slaughter Jan 2025

Laser-Induced Graphene For Early Disease Detection: A Review, Sri Ramulu Torati, Gymama Slaughter

Center for Bioelectronics Publications

Electrochemical biosensors have been instrumental in early disease detection, facilitating effective monitoring and treatment. The emergence of graphene has significantly advanced sensor technology in various fields, including biomedicine, electronics, and energy. In this landscape, laser‐induced graphene (LIG) has emerged as a superior alternative to conventional graphene synthesis methods. Its straightforward fabrication process and compatibility with wearable devices boost its practicality and potential for real‐world applications. This review highlights the transformative potential of LIG in biosensing, showcasing its contributions to the development of next‐generation diagnostic tools for early disease detection. An overview of the LIG synthesis process and its applications in …


Passive Thermal Control Technologies: Short Course, Holly Mortensen, Matt Ralphs Jan 2025

Passive Thermal Control Technologies: Short Course, Holly Mortensen, Matt Ralphs

Space Dynamics Laboratory Publications

  • Introduction to Space Dynamics Laboratory
  • Overview - Thermal Control Technologies
  • Conductor Bars
  • Thermal Straps
  • Break
  • Radiators
  • Thermal Switches


Phase Change Cells, T. Shane Topham, Gail Bingham, Harry Latvakoski, Mike Watson Jan 2025

Phase Change Cells, T. Shane Topham, Gail Bingham, Harry Latvakoski, Mike Watson

Space Dynamics Laboratory Publications

Outline

  • Phase Change Cell Introduction
  • Summary of ISS Phase Change Cell Experiments
  • Ground Cell Design Improvements and Test Results


Space Dynamics Laboratory, Brent Carlsen, Doug Jewell Jan 2025

Space Dynamics Laboratory, Brent Carlsen, Doug Jewell

Space Dynamics Laboratory Publications

  • Space Dynamics Laboratory
  • SDL is a UARC
  • RE-SET (Re-Engineering, System Engineering & Test)
  • System Test Development


Development Of A Design Tool For Tow-Steered Composite Structures With Machine Learning-Assisted Modeling, Bangde Liu Jan 2025

Development Of A Design Tool For Tow-Steered Composite Structures With Machine Learning-Assisted Modeling, Bangde Liu

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Fiber-reinforced composites (FRCs) are widely used in aerospace, automotive, and other engineering applications due to their lightweight characteristics and superior mechanical properties. Traditional FRCs employ a fixed fiber orientation in each layer, and while different layup sequences can tailor performance, the mechanical properties remain spatially uniform. Tow-steered composites, which enable fibers to follow curvilinear paths, offer the potential for spatially varying stiffness and strength, improving structural performance.

This dissertation addresses key challenges in modeling and designing tow-steered composite structures, including the lack of commercial design tools, the high computational cost of design optimization, and the need to efficiently evaluate manufacturing …


Assessing Porosity Limit In Freeze-Cast Sintered Lithium Titanate (Li₄Ti₅O₁₂) Materials, Rohan Parai, Dipankar Ghosh Jan 2025

Assessing Porosity Limit In Freeze-Cast Sintered Lithium Titanate (Li₄Ti₅O₁₂) Materials, Rohan Parai, Dipankar Ghosh

Mechanical & Aerospace Engineering Faculty Publications

This study aims to assess the lower limit of porosity that can be achieved in freeze-cast sintered lithium titanate (LTO) materials while maintaining the characteristic pore directionality. LTO materials were fabricated with solid loading varying in the range of 30–37 vol.%. Sucrose and cationic dispersant were used to vary viscosity and total solute concentration in the aqueous LTO suspensions. Two series of suspension compositions were selected for freeze-casting. In one series, aqueous suspensions were prepared by mixing deionized (DI) water, sucrose, and LTO powder, while in the other series, aqueous suspensions were prepared by mixing DI water, sucrose, cationic dispersant …


Morphing Shape Metastructures Using The Hybrid Position Feedback Control And Bistable Structural Elements, Mehmet Simsek, Thomas E. Alberts, Onur Bilgen Jan 2025

Morphing Shape Metastructures Using The Hybrid Position Feedback Control And Bistable Structural Elements, Mehmet Simsek, Thomas E. Alberts, Onur Bilgen

Mechanical & Aerospace Engineering Faculty Publications

This research introduces a new multi-degree-of-freedom metastructure concept utilizing a hybrid position feedback controller. An arbitrary number of bistable segments, or structural elements, are connected serially or in parallel to form a distributed bistable structure, or a so-called metastructure. The hybrid controller, an unstable-then-stable second-order single-degree-of-freedom system, leverages the resonant mode of a bistable system to destabilize it and dynamically induce snap-through between equilibria. The metastructure inherits multiple bistable positions, maintaining equilibrium shapes without consuming power and enabling many equilibrium configurations. Two geometric configurations are proposed and analyzed using a modified hybrid feedback control approach, which rejects forces from neighboring …


Deriving Nonlinearity Coefficients From Changing Background, Mark Esplin, Deron Scott, Bryce Walker, Ben Esplin Jan 2025

Deriving Nonlinearity Coefficients From Changing Background, Mark Esplin, Deron Scott, Bryce Walker, Ben Esplin

Space Dynamics Laboratory Publications

Contents

  • Quadric Nonlinearity
  • Nonlinearity Model and Sensitivity Studies
  • Application to CrIS Sensor
  • Check Method with Stepped Blackbody Data
  • Conclusions


Guidelines For Radiometric Calibration Of Electro-Optical Instruments For Remote Sensing, Utah State University Space Dynamics Laboratory Jan 2025

Guidelines For Radiometric Calibration Of Electro-Optical Instruments For Remote Sensing, Utah State University Space Dynamics Laboratory

Space Dynamics Laboratory Publications

SDL Presentation on Radiometric Calibration of Electro-Optical Instruments for Remote Sensing


Deep Learning Approaches For Predicting Strain Energy In Heterogeneous Materials, Junesh Gautam Jan 2025

Deep Learning Approaches For Predicting Strain Energy In Heterogeneous Materials, Junesh Gautam

Electronic Theses and Dissertations

Finite Element Analysis (FEA) faces computational challenges when analyzing nonlinear and heterogeneous materials. Utilizing the Mechanical MNIST dataset, comprising 60,000 simulated samples of 28x28 pixel domains under large deformation, the study evaluates classical regression methods (Linear Regression, Random Forest, Gradient Boosting) and advanced deep learning architectures (Convolutional Neural Networks (CNN) and Residual Networks (ResNet)). CNN models achieved superior performance, with a Mean Squared Error (MSE) of 4.21 and an R2 value of approximately 0.982, outperforming classical regression models and slightly surpassing ResNet architectures. These deep learning methods automatically learn spatial relationships from pixel-based representations, eliminating the need for manual feature …


Membrane Reactor Modeling And Optimization For Hydrogen Production, Ayooluwa Tomiwa Akintola Jan 2025

Membrane Reactor Modeling And Optimization For Hydrogen Production, Ayooluwa Tomiwa Akintola

Graduate Theses, Dissertations, and Problem Reports (ETD)

There has been an ongoing trend toward cleaner fuels for more environmentally benign forms of energy generation. Recently, hydrogen has been identified as a clean fuel for energy generation. However, the most established, efficient, and widely utilized technique for producing hydrogen remains the steam methane reforming (SMR) in the presence of catalyst. Unlike other fossil fuels, utilizing methane from natural gas in an SMR process to produce hydrogen emits less, but yet a notable sum of carbon dioxide. Furthermore, the endothermic nature of SMR reactions imply that there is a high energy requirement to obtain a substantial amount of hydrogen …


La2nio4+Δ-Based Solid Oxide Electrolysis Cell (Soecs) Electrodes Enhanced With Complex Perovskite Nanocatalyst Processed By Surfactant-Enabled Infiltration, Cole Samuel Klemstine Jan 2025

La2nio4+Δ-Based Solid Oxide Electrolysis Cell (Soecs) Electrodes Enhanced With Complex Perovskite Nanocatalyst Processed By Surfactant-Enabled Infiltration, Cole Samuel Klemstine

Graduate Theses, Dissertations, and Problem Reports (ETD)

As the world seeks to reduce its reliance on hydrocarbons, the demand for sustainable hydrogen production methods has become increasingly critical. Hydrogen is a versatile energy carrier that can be produced from various sources, including water, natural gas, and biomass. Replacing the burning of hydrocarbons with hydrogen could significantly reduce greenhouse gas emissions, contributing to global climate goals like those set by the US H2NEW program. The joint technologies of solid oxide fuel and electrolysis cells present the ability to both produce and process clean hydrogen to meet these goals. Development into solid oxide fuel cells has been met with …


Reuse Of Calcium Carbonate (Caco3) Recovered From Discarded Carpets As Filler In Fiber-Reinforced Polymer (Frp) Composites, Roshan Devkota Jan 2025

Reuse Of Calcium Carbonate (Caco3) Recovered From Discarded Carpets As Filler In Fiber-Reinforced Polymer (Frp) Composites, Roshan Devkota

Graduate Theses, Dissertations, and Problem Reports (ETD)

Over four billion pounds of carpet are discarded annually in the United States, making carpet waste a significant environmental concern. Calcium carbonate (CaCo₃) constitutes up to 45% of the mass of most synthetic carpets. Reusing this CaCo₃ as a filler in the rapidly growing fiber-reinforced polymer (FRP) industry, which is projected to reach USD 10.38 billion, presents a low-cost, practical approach to developing a market-based solution to post-consumer carpet waste.

This study investigates the reuse of CaCo₃ recovered from discarded carpet backing as a filler in FRP composites, focusing on its mechanical viability in comparison to virgin CaCo₃. The methodology …


Engineering Nanomaterials From Phase-Change Biological Materials Reacting With Carbon Dioxide, Qingyang Li Jan 2025

Engineering Nanomaterials From Phase-Change Biological Materials Reacting With Carbon Dioxide, Qingyang Li

Graduate Theses, Dissertations, and Problem Reports (ETD)

The current global situation concerning CO2 emissions is increasingly alarming, with rising concentrations of CO2 significantly worsening climate change and global warming. Atmospheric CO2 levels are now at their highest in millions of years, driving a host of catastrophic effects, including but not limited to extreme weather events, rising sea levels, ocean acidification, disrupted ecosystems, deteriorating air quality, respiratory health issues, heat-related illnesses, threats to food and water security, and escalating social and geopolitical tensions. To keep global warming to no more than 1.5°C higher than that of pre-industry – as called for in the Paris Agreement – emissions need …


Numerical Investigation Of Pressurized Oxy-Combustion, Lei Li Jan 2025

Numerical Investigation Of Pressurized Oxy-Combustion, Lei Li

Graduate Theses, Dissertations, and Problem Reports (ETD)

Pressurized oxy-combustion (POC) is emerging as a promising and transformative technology for carbon capture, utilization, and storage, offering advantages of low cost, low emissions, and high efficiency. POC operates by burning pulverized coal at elevated pressures in a recycled flue gas environment, typically rich in O₂ and CO₂. This study presents a comprehensive numerical investigation into the fundamental behaviors of lab-scale POC reactors, using both two-dimensional (2D) Reynolds-Averaged Navier-Stokes (RANS) simulations and three-dimensional (3D) Large-Eddy Simulations (LES) with the commercial computational fluidized dynamics (CFD) software package ANSYS Fluent.

The primary focus of this work is to understand flame stabilization and …


Modeling And Simulation Of Carbon-Neutral Strategies For Methanol Production, Omar Almaraz Barrios Jan 2025

Modeling And Simulation Of Carbon-Neutral Strategies For Methanol Production, Omar Almaraz Barrios

Graduate Theses, Dissertations, and Problem Reports (ETD)

Methanol is a versatile chemical that can be used as a fuel, a solvent, a feedstock for other chemicals, and a hydrogen carrier. Methanol production from natural gas, which is mainly composed of methane, is a well-established process that involves steam reforming, methanol synthesis, and methanol purification. However, this process is energy-intensive and emits large amounts of carbon dioxide, which contributes to global warming and climate change. Therefore, there is a need for alternative methods of methanol production that are more efficient and environmentally friendly. The overall objective of this research is to develop simulation models of two novel methanol …


Finite Element Modeling And Experimental Characterization Of Overmolded Gold-Palladium Composite Leads And Their Mechanical Behavior Under Cyclic Fatigue For Long-Term Implant Applications, Tanner Davis Jan 2025

Finite Element Modeling And Experimental Characterization Of Overmolded Gold-Palladium Composite Leads And Their Mechanical Behavior Under Cyclic Fatigue For Long-Term Implant Applications, Tanner Davis

Graduate Theses, Dissertations, and Problem Reports (ETD)

Auditory Nerve Interface (ANI) devices, currently in developmental stages, represent an emerging neuroprosthetic approach to restore hearing in severe sensorineural loss patients by directly stimulating the auditory nerve via the Utah Slanted Electrode Array (USEA). Conventional implant leads are comprised of multiple wires made from materials such as platinum-iridium and MP35N stainless steel that are overmolded in an insulative material. These materials are not possible to bond with to electrode array used in the ANI device, necessitating the evaluation of a new material like Au-Pd to ensure its functionality and durability under cyclic stresses. This gap necessitates characterization of alternative …


Autonomous Vehicle Supported Mobility Services For Rural Areas, Alvira Ahmed Tasnim Jan 2025

Autonomous Vehicle Supported Mobility Services For Rural Areas, Alvira Ahmed Tasnim

Graduate Theses, Dissertations, and Problem Reports (ETD)

Autonomous Vehicles (AVs) are emerging as a promising mobility solution to address growing transportation demands, particularly unmet traffic demand in rural areas where conventional transit systems often fall short. Rural areas face unique mobility challenges due to dispersed populations, limited infrastructure, and low/no transit coverage. Existing transit services tend to concentrate around dense urban cores, leaving low-demand areas outside underserved. This spatial undercoverage leads to significant mobility gaps for rural residents. This study examines the potential of AV-based ride-sharing services to address these mobility needs by providing flexible, demand-responsive mobility services where fixed-route transit services are either economically or operationally …