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Articles 691 - 720 of 21777

Full-Text Articles in Engineering

A New Deep Decoder Type Cascaded Feedforward Neural Network For Critical Heat Flux Prediction In Power Reactors, Rehan Zubair Khalid, Atta Ullah, Asifullah Khan, Mansoor Hameed Inayat, Muthanna H. Al-Dahhan Jan 2025

A New Deep Decoder Type Cascaded Feedforward Neural Network For Critical Heat Flux Prediction In Power Reactors, Rehan Zubair Khalid, Atta Ullah, Asifullah Khan, Mansoor Hameed Inayat, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Critical Heat Flux (CHF) is a fundamental parameter for ensuring the performance, reliability, safety, and economic viability of water-cooled nuclear reactors. Despite its significance, the absence of a deterministic theory for CHF prediction poses a substantial challenge in thermal engineering. Consequently, various experimental and numerical models have been developed, yet no universally accepted model comprehensively addresses the wide range of flow conditions encountered in practical applications. The accurate prediction of CHF remains a complex and critical task. This work introduces a novel Deep Decoder Type Cascaded feedforward Neural Network (DD-CFNN) to predict CHF across a broad spectrum of operating conditions. …

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Experimental Investigation Of Heat Transfer Behavior In Spouted Bed Reactors Under Different Operating Conditions, Hasan A. Abdulwahab, Abbas J. Sultan, Amer A. Abdulrahman, Hasan Sh Majdi, Haydar A.S. Aljaafari, Zahraa W. Hasan, Laith S. Sabri, Bashar J. Kadhim, Jamal M. Ali, Muthanna H. Al-Dahhan Jan 2025

Experimental Investigation Of Heat Transfer Behavior In Spouted Bed Reactors Under Different Operating Conditions, Hasan A. Abdulwahab, Abbas J. Sultan, Amer A. Abdulrahman, Hasan Sh Majdi, Haydar A.S. Aljaafari, Zahraa W. Hasan, Laith S. Sabri, Bashar J. Kadhim, Jamal M. Ali, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Abstract: Spouted bed reactors (SBRs) are highly valued for their effectiveness in chemical and biochemical processes due to their mixing and heat transfer capabilities. Understanding the heat transfer mechanisms in these reactors is necessary. This research delves into the heat transfer behavior of SBRs, which plays a role in enhancing their performance under operational conditions. The study conducted experiments to measure the heat transfer coefficient (HTC) at varying gas velocities (ranging from 0.32 to 0.74 m/s) at radial positions (r/R = 0, ±0.28, ±0.56, and ±0.85) and axial levels (H/D = 0.8, 2.1, and 3.5) within the spouted bed (SB) …

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Tumor Microenvironment Immunomodulation By Nanoformulated Tlr 7/8 Agonist And Pi3k Delta Inhibitor Enhances Therapeutic Benefits Of Radiotherapy, Mostafa Yazdimamaghani, Oleg V. Kolupaev, Chaemin Lim, Duhyeong Hwang, Sonia J. Laurie, Charles M. Perou, Alexander V. Kabanov, Jonathan S. Serody Jan 2025

Tumor Microenvironment Immunomodulation By Nanoformulated Tlr 7/8 Agonist And Pi3k Delta Inhibitor Enhances Therapeutic Benefits Of Radiotherapy, Mostafa Yazdimamaghani, Oleg V. Kolupaev, Chaemin Lim, Duhyeong Hwang, Sonia J. Laurie, Charles M. Perou, Alexander V. Kabanov, Jonathan S. Serody

Chemical and Biochemical Engineering Faculty Research & Creative Works

Infiltration of immunosuppressive cells into the breast tumor microenvironment (TME) is associated with suppressed effector T cell (Teff) responses, accelerated tumor growth, and poor clinical outcomes. Previous studies from our group and others identified infiltration of immunosuppressive myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs) as critical contributors to immune dysfunction in the orthotopic claudin-low tumor model, limiting the efficacy of adoptive cellular therapy. However, approaches to target these cells in the TME are currently lacking. To overcome this barrier, polymeric micellular nanoparticles (PMNPs) were used for the co-delivery of small molecule drugs activating Toll-like receptors 7 and 8 …

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Machine Learning Modeling For Hydrolysis Recycling Of Pet Waste, Jie Li, Lanjia Pan, Hossein Abedsoltan, Hailong Wang, Taiyang Liu, Xiangzhou Yuan, Yong Sik Ok, Yin Wang Jan 2025

Machine Learning Modeling For Hydrolysis Recycling Of Pet Waste, Jie Li, Lanjia Pan, Hossein Abedsoltan, Hailong Wang, Taiyang Liu, Xiangzhou Yuan, Yong Sik Ok, Yin Wang

Chemical and Biochemical Engineering Faculty Research & Creative Works

The hydrolysis of polyethylene terephthalate (PET) into terephthalic acid (TPA) can efficiently recycle waste PET, but achieving high conversion efficiency through smart reaction design remains challenging. To develop a robust and accurate machine learning (ML) model for the in-depth understanding and intelligent design of PET hydrolysis, we compiled a new dataset comprising 942 data points and comprehensive information of 44 variables involved in heating type, acid/base catalyst (ABC), organic solvent (OS), co-solvent (CS), phase transfer catalyst (PTC), and operational conditions. The developed Neural Network model demonstrated the best performance in predicting PET conversion, with a testing determination coefficient (R2 …

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Mechanistic Scale-Up Of Gas-Solid Fluidized Beds Via Local Hydrodynamic Similarity, Faraj M. Zaid, Thaar M. Aljuwaya, Muthanna H. Al-Dahhan Jan 2025

Mechanistic Scale-Up Of Gas-Solid Fluidized Beds Via Local Hydrodynamic Similarity, Faraj M. Zaid, Thaar M. Aljuwaya, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

This study presents a detailed experimental evaluation of a newly developed mechanistic scale-up methodology for gas-solid fluidized beds. Traditional scale-up approaches typically rely on matching global dimensionless groups, which often fail to ensure local hydrodynamic similarity. In contrast, the new mechanistic method aims to achieve scale-up by matching the radial profiles of gas holdup between geometrically similar beds at corresponding dimensionless axial positions (z/Dc). This approach is based on the premise that when gas holdup profiles align, other key hydrodynamic parameters—such as solids holdup and particle velocity—also become similar. To validate this methodology, experiments were conducted in two …

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Pla-Based Bone Tissue Engineering Scaffolds Incorporating Hydroxyapatite And Bioactive Glass Using Digital Light Processing, Engin Gepek, Fateme Fayyazbakhsh, Lev Suliandziga, Vadym Mochalin, Osman Iyibilgin, Yue-Wern Huang, Ming C. Leu Jan 2025

Pla-Based Bone Tissue Engineering Scaffolds Incorporating Hydroxyapatite And Bioactive Glass Using Digital Light Processing, Engin Gepek, Fateme Fayyazbakhsh, Lev Suliandziga, Vadym Mochalin, Osman Iyibilgin, Yue-Wern Huang, Ming C. Leu

Chemistry Faculty Research & Creative Works

Bone tissue engineering (BTE) aims to repair bone defects using biocompatible materials with tailored geometries and pore structures, providing appropriate mechanical support and control over biodegradation kinetics to promote bone growth. In this study, we utilized digital light processing (DLP) 3D printing to fabricate scaffolds with varying pore sizes using polymer–ceramic slurries composed of polylactic acid (PLA) as the main polymer matrix, incorporated with hydroxyapatite (HA) and bioactive borate glass (BBG) at various ratios. We studied the effect of composition on rheological behavior, printability, mechanical properties, bioactivity, degradation rate, and biocompatibility. While HA increased viscosity and reduced printing accuracy, it …

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Mechanical And Thermal Characterization Of Additively Manufactured Carbon/Nylon 12 And Carbon/Peek Composites, Matik Heskin, Bradley Deuser, Thomas P. Schuman, K. Chandrashekhara, John Bayldon, Jeff Degrange, Steven Patterson, Neiko Levenhagen Jan 2025

Mechanical And Thermal Characterization Of Additively Manufactured Carbon/Nylon 12 And Carbon/Peek Composites, Matik Heskin, Bradley Deuser, Thomas P. Schuman, K. Chandrashekhara, John Bayldon, Jeff Degrange, Steven Patterson, Neiko Levenhagen

Chemistry Faculty Research & Creative Works

This study explores additive manufacturing of carbon fiber-reinforced thermoplastic composites using the Composite-Based Additive Manufacturing (CBAM) process. Carbon/Nylon 12 and Carbon/PEEK composites were fabricated and evaluated through mechanical (compression, tensile, flexural, and impact) and thermal (DSC and TGA) tests. Carbon/PEEK exhibited superior mechanical performance, with 97.5% higher tensile strength, 79.8% higher elastic modulus, and 59.6% higher flexural strength compared to Carbon/Nylon 12. Thermal testing showed that Carbon/PEEK had higher thermal stability, beginning degradation at 350 °C versus 298 °C for Carbon/Nylon. These results indicate that CBAM-fabricated Carbon/PEEK composites are suitable for applications requiring high strength and temperature resistance.

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Navigation In Underground Mine Environments: A Simulation Framework For Quadruped Robots, Yixiang Gao, Kwame Awuah-Offei Jan 2025

Navigation In Underground Mine Environments: A Simulation Framework For Quadruped Robots, Yixiang Gao, Kwame Awuah-Offei

Mining Engineering Faculty Research & Creative Works

Quadruped robots have shown significant potential for navigating complex and hazardous environments, such as underground mines, where traditional wheeled or tracked systems have limitations. However, their development and deployment are hindered by the disparity between controlled laboratory testing and real-world conditions and the lack of tools (e.g., simulation testbeds) that expedite the required development and testing. This work develops a simulation testbed for expediting and advancing navigation algorithms, perception systems, and control strategies for quadruped robots in subterranean and hazardous environments. By utilizing high-fidelity 3D maps, ranging from intricate cave systems to real-world sites like the Edgar Mine, simulation environment …

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Optimizing Acid Mist Suppression: Unraveling Surfactant Effects On Bubble Formation And Bursting Dynamics In Copper Electrowinning, Ashish Kakoria, Mirza Muhammad Zaid, Aamir Iqbal, Ellen Amoako Afful, Guang Xu Jan 2025

Optimizing Acid Mist Suppression: Unraveling Surfactant Effects On Bubble Formation And Bursting Dynamics In Copper Electrowinning, Ashish Kakoria, Mirza Muhammad Zaid, Aamir Iqbal, Ellen Amoako Afful, Guang Xu

Mining Engineering Faculty Research & Creative Works

The working mechanism of surfactant to reduce acid mist in copper electrowinning system is not well understood. Most of the studies are based on the surface tension reduction phenomenon but this is not the only function that causes acid mist reduction. In this paper, we investigated the effect of different surfactants on a bubble's residence time, terminal velocity, flow regime, and bursting dynamics using a high-speed camera. We have evaluated five different surfactants and found that the presence of surfactants reduces the terminal velocity, bubble diameter, and increases the residence time of the bubble in electrolyte. Especially for FC-1100, the …

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A Ground Thermal Vacuum Facility For Simulating Cryogenic Space Environment Conditions, Emmanuel Kofi Asuako Wie-Addo, Lucas Scott, Daoru Han Jan 2025

A Ground Thermal Vacuum Facility For Simulating Cryogenic Space Environment Conditions, Emmanuel Kofi Asuako Wie-Addo, Lucas Scott, Daoru Han

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This work presents the ongoing progress of a vacuum facility upgrade at the Gas and Plasma Dynamics Laboratory (GPDL) at Missouri University of Science and Technology. A movable shroud has been fabricated and installed to enable the simulation of extreme cold conditions. The cooling rate of the shroud, a dummy test article, and a platform, using liquid nitrogen as the thermal fluid, is analyzed and reported under varying vacuum conditions for cryogenic runs. Preliminary testing revealed substantial thermal exchange between the shroud and the chamber walls, underscoring the necessity for implementing effective thermal isolation measures to mitigate heat transfer.

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Arc-Jet And Free-Flight Evaluation Of Laminar And Turbulent Diffusion Models On Ablation, Kyle Worden, Andrew Heider, Serhat Hosder Jan 2025

Arc-Jet And Free-Flight Evaluation Of Laminar And Turbulent Diffusion Models On Ablation, Kyle Worden, Andrew Heider, Serhat Hosder

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper investigates the effect of diffusion models on carbon ablation with a parametric study on a slug-calorimeter geometry in arc-jet flow at two enthalpy conditions using two arc-jet flow modeling approaches, and at corresponding enthalpy-matched free-flight conditions using RANS CFD simulations. Additionally, a sphere-cone geometry is modeled at the arc-jet enthalpy matched free-flight conditions and at a high Reynolds number free-flight condition. The approximate-corrected form of Fick's law and the Stefan-Maxwell diffusion models are investigated for equilibrium and finite-rate carbon ablation in laminar and turbulent flows, which is simulated with the Menter-SST turbulence model. The turbulent cases include the …

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An Adaptive Sampling Strategy On Optimal Takeoff Trajectory Prediction Of Electric Drones, Dheeraj Paramkusham, Samuel Sisk, Jiachen Wang, Shuan Tai Yeh, Xiaosong Du, Nathan Roberts Jan 2025

An Adaptive Sampling Strategy On Optimal Takeoff Trajectory Prediction Of Electric Drones, Dheeraj Paramkusham, Samuel Sisk, Jiachen Wang, Shuan Tai Yeh, Xiaosong Du, Nathan Roberts

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Electric vertical takeoff and landing (eVTOL) aircraft transforms future transportation systems by alleviating transportation congestion on the ground. This eVTOL technique possesses unique features, including reduced noise, low pollutant emissions, efficient operating costs, and flexible maneuverability. Meanwhile, battery consumption poses critical challenges to flight task duration. Thus, optimal takeoff trajectory design is essential due to immense power demands during eVTOL takeoffs. Conventional design optimization, however, iteratively evaluates high fidelity simulation models, making the design process computationally intensive. In this work, we implement a machine learning-enabled inverse mapping optimization concept, i .e., directly predicting optimal design based on design requirements (including …

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Study On Field Emission Characteristics Of Carbon Nanotube Arrays Patterned Via Laser Welding Of Dissimilar Materials, Hung Yin Tsai, Yi Hung Chen, Kuan Ching Wang, Paul W. Leu, Ming C. Leu Jan 2025

Study On Field Emission Characteristics Of Carbon Nanotube Arrays Patterned Via Laser Welding Of Dissimilar Materials, Hung Yin Tsai, Yi Hung Chen, Kuan Ching Wang, Paul W. Leu, Ming C. Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper describes a new method of growing carbon nanotube (CNT) arrays using laser welding of a catalyst metal onto the surface of a quartz substrate, followed by CNT growth through the chemical vapor deposition (CVD) process. A major advantage of this method is its ability to pattern the catalyst before growing the CNTs, thus allowing for the formation of CNTs at specific locations. The laser pre-treatment method minimized structural damage to CNTs in comparison to the laser post-processing method, achieving a lower ID/IG value of 0.72 in Raman spectroscopy analysis. Using hexagonally patterned CNT arrays on quartz, we achieve …

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Correction: Advancing Cislunar Space Domain Awareness Through Robust Optimization Framework For Optical Sensors-Based Autonomous Satellite Systems (American Institute Of Aeronautics And Astronautics Inc, Aiaa), Smriti Nandan Paul, Siwei Fan, Igor Panfil Jan 2025

Correction: Advancing Cislunar Space Domain Awareness Through Robust Optimization Framework For Optical Sensors-Based Autonomous Satellite Systems (American Institute Of Aeronautics And Astronautics Inc, Aiaa), Smriti Nandan Paul, Siwei Fan, Igor Panfil

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Correction Notice • Page 8: "$\lambda_2$: It represents the cardinality-weighted" corrected to "$\lambda_2$: It represents the inverse of cardinality-weighted." Equation $\lambda_2=\sum_{i=1}^{10}(n_i\Xi_i)$ corrected to $\lambda_2=1/(\sum_{i=1}^{10}(n_i \Xi_i))$ • Page 11: Table 1 is updated with new orbital families and number of satellites & 1 & $L_2$ Halo south|$L_1$ Halo north|Butterfly south & 1|2|3\\ & 2 & $L_1$ Halo north|$L_2$ Halo south|Dragonfly south & 5|10|3\\ & 3 & Butterfly south|$L_2$ Halo south|$L_2$ Lyapunov & 3|10|4\\ & 4 & $L_1$ Halo south|$L_2$ Halo north|$L_1$ Halo north & 5|3|1\\ A|B|C & 5 & $L_2$ Halo south|$L_1$ Lyapunov|$L_2$ Halo north & 2|8|9\\ & 6 & $L_3$ …

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High-Order Dynamic Mode Decomposition For Multidimensional Harmonic Retrieval, Yanming Zhang, Steven Gao, Lijun Jiang Jan 2025

High-Order Dynamic Mode Decomposition For Multidimensional Harmonic Retrieval, Yanming Zhang, Steven Gao, Lijun Jiang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Estimating channel parameters such as azimuth, elevation, Doppler shift, and delay is a key challenge in wireless communication, often formulated as a multidimensional harmonic retrieval (MHR) problem. To address this, we propose a high-order dynamic mode decomposition (HODMD) framework for robust frequency estimation from high-dimensional signals in noisy environments. The HODMD approach combines high-order singular value decomposition (HOSVD) to decompose tensor data into a core tensor and mode matrices, with dynamic mode decomposition (DMD) to extract frequencies from the imaginary parts of the DMD eigenvalues. Simulation examples validate the effectiveness of the proposed method, demonstrating its efficiency in solving MHR …

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Performance Evaluation And Multiphysics Process Modeling Of Carbon Fiber Reinforced Thermoset Composites Using Microwave And Autoclave, Nayan Pundhir, Patrick Schwartzkopf, K. Chandrashekhara, Logan Wilcox, Kristen M. Donnell, Jim Lua, Rui Li Jan 2025

Performance Evaluation And Multiphysics Process Modeling Of Carbon Fiber Reinforced Thermoset Composites Using Microwave And Autoclave, Nayan Pundhir, Patrick Schwartzkopf, K. Chandrashekhara, Logan Wilcox, Kristen M. Donnell, Jim Lua, Rui Li

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this study, IM7/Cycom 5320-1 unidirectional prepreg has been utilized to manufacture 16-layer laminated composites: a symmetric cross-ply ([0°/90°]4s) and a quasi-isotropic ([45°/90°/−45°/0°]2s) configuration. Microwave and autoclave curing processes have been employed to manufacture the laminated composites. The manufactured composite cure was assessed using differential scanning calorimetry (DSC). The quality and porosity of the microwave-cured parts were juxtaposed to those of autoclave-cured parts through optical microscopy and micro-computed tomography (micro-CT) scanning. Mechanical characterization of the microwave-cured panels was conducted using uniaxial tensile and flexural tests, with results juxtaposed to autoclave-cured samples. Experimental characterization revealed that the microwave-cured parts exhibited nearly …

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Design And Testing Of An Intrusive Arm For Supersonic Flow Sampling, Caleb Roberts, Davide Viganò Jan 2025

Design And Testing Of An Intrusive Arm For Supersonic Flow Sampling, Caleb Roberts, Davide Viganò

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Intrusive probes are critical tools in supersonic wind tunnel testing, enabling direct measurement of flow properties such as pressure and heat flux. To support these measurements, a single-axis intrusive arm was designed and implemented in the Missouri S&T Supersonic Wind Tunnel. The system is designed to maintains precise probe positioning, while withstanding the aerodynamic loads, and preserving a dynamic seal between the test section and ambient environment. Its modular design accommodates a range of probe types for various research applications. This paper presents the design methodology, including structural, mechanical, and aerodynamic considerations, and details the integration process. System performance was …

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Deep Reinforcement Learning-Based Optimal Takeoff Trajectory Design Of An Evtol Drone, Nathan M. Roberts, Bingling Huang, Xiaosong Du Jan 2025

Deep Reinforcement Learning-Based Optimal Takeoff Trajectory Design Of An Evtol Drone, Nathan M. Roberts, Bingling Huang, Xiaosong Du

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The continuing development of electric vertical take-off and landing (eVTOL) aircraft presents promising opportunities to alleviate transportation congestion. However, designing and executing takeoff trajectories that optimally balance energy usage, passenger comfort, and aircraft constraints remains challenging. Conventional design optimization provides a solution for pre-defined flight conditions and environments but is not ideal in real-world applications. In contrast, deep reinforcement learning (DRL) implements optimal policy making real-time decisions with no assumption of mathematical models. Seeing the lack of literature on DRL-based takeoff trajectory design of eVTOL aircraft, we implement and conduct DRL-based optimal takeoff trajectory designs for the Airbus3 Vahana …

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Industry 5.0, Human–Machine Interface, And Smart Manufacturing In Additive Manufacturing—A Recent Trend, Atiqur Rahman, Md Hazrat Ali, Muhammad Arif Mahmood, Frank Liou Jan 2025

Industry 5.0, Human–Machine Interface, And Smart Manufacturing In Additive Manufacturing—A Recent Trend, Atiqur Rahman, Md Hazrat Ali, Muhammad Arif Mahmood, Frank Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The emergence and importance of Industry 5.0 are transforming production by integrating smart technology with human creativity and intelligence, especially in advanced additive manufacturing. This critical review precisely analyzes the function of human–machine interfaces (HMIs) in enhancing additive processes, emphasizing their incorporation into smart manufacturing systems and hybrid manufacturing methods, including material extrusion (MEX), laser powder bed fusion (LPBF), and directed energy deposition (DED). It also evaluates artificial intelligence (AI), the Internet of Things (IoT), and cybersecurity, which enhance HMIs in process monitoring, operation, and system adaptability. This study aims to provide a critical analysis and future research direction on …

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Optimizing Uav Swarm Deployment For Efficient Communication Signal Strength Alignment In Disaster Scenarios, Mina Khalilzadeh Fathi, Chaoying Pei Jan 2025

Optimizing Uav Swarm Deployment For Efficient Communication Signal Strength Alignment In Disaster Scenarios, Mina Khalilzadeh Fathi, Chaoying Pei

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In disaster scenarios, establishing reliable communication infrastructure is critical, and unmanned aerial vehicle (UAV) swarms offer a promising solution as temporary base stations. This study models communication demand in disaster-affected areas by applying Gaussian kernels to building data, forming a spatial demand distribution. Signal strength is estimated using the normalized inverse Free Space Path Loss (FSPL) to account for realistic attenuation. To guide UAV placement, we extract high-demand regions from the demand distribution using a gradient-based thresholding method. Based on this information, we develop a greedy algorithm to iteratively position UAVs for optimal coverage in areas with the greatest communication …

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Few-Shot Learning-Enhanced Tiered Path Planning For Mars Rover Navigation, Ziyi Wang, Di Yu, Mina Khalilzadeh Fathi, Chaoying Pei Jan 2025

Few-Shot Learning-Enhanced Tiered Path Planning For Mars Rover Navigation, Ziyi Wang, Di Yu, Mina Khalilzadeh Fathi, Chaoying Pei

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Path planning for Mars rovers presents significant challenges due to the diverse terrain, ranging from easily navigable areas to hazardous zones. Traditional methods typically classify terrain simply as passable or impassable, failing to account for the nuances of more moderately challenging areas. In this paper, we introduce a tiered terrain-aware path planning strategy, employing few-shot learning to classify and segment Martian terrain into levels of difficulty. The few-shot learning model, trained on Earth, is sent to the rover, enabling real-time processing of images from satellites or helicopters. The flexibility of few-shot learning, which requires minimal data and training time, enables …

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2d Numerical Modeling Of Pavements On Expansive Soil In Extreme Climates, Ekansh Agarwal, Xiong Zhang, Ning Luo Jan 2025

2d Numerical Modeling Of Pavements On Expansive Soil In Extreme Climates, Ekansh Agarwal, Xiong Zhang, Ning Luo

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study focuses on modeling a rigid pavement slab on expansive soil in extreme climates to understand the interaction between weather, pavement, and soil. Lightweight superstructures such as pavements are particularly prone to damage due to the differential settlement of expansive soils. In the context of climate change, the occurrence of severe droughts followed by intense rainfall has risen, causing severe impacts on crack initiation and development, and thus infiltration patterns in the structures built on expansive soils. Pavements are typically designed for a limited lifespan, and early failure may occur if climate change is not considered during design. This …

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Identifying Potential Risk Areas Close To The Oil And Gas Pipelines Due To Subsidence In Qazvin Plain, Mahmoud Rajabi, Sanaz Vajedian, Ryan Smith, Neil Grigg, Hossein Nahavandchi, Mehdi Goli Jan 2025

Identifying Potential Risk Areas Close To The Oil And Gas Pipelines Due To Subsidence In Qazvin Plain, Mahmoud Rajabi, Sanaz Vajedian, Ryan Smith, Neil Grigg, Hossein Nahavandchi, Mehdi Goli

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Surface displacement caused by natural and anthropogenic activities poses a significant risk to subsurface pipelines, particularly in areas experiencing subsidence. Stress and strain induced by deformation can lead to pipeline buckling and potential vulnerability. This study applies a multidisciplinary approach integrating interferometric synthetic aperture radar (InSAR) deformation analysis, well data, and geological context to assess the risk to oil and gas pipelines in Iran's Qazvin plain. The focus is on evaluating the impact of an unconfined aquifer, which has a lower risk of subsidence compared to a confined aquifer, on pipeline infrastructure. We analyzed multitemporal Sentinel-1 data collected between 2014 …

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Influence Of Alloy Composition On The Process Robustness Of Steels Consolidated Via Laser-Directed Energy Deposition, Jonathan Kelley Jan 2025

Influence Of Alloy Composition On The Process Robustness Of Steels Consolidated Via Laser-Directed Energy Deposition, Jonathan Kelley

Masters Theses

"To ensure consistent quality of additively manufactured parts, it is advantageous to identify alloys which can meet performance criteria while being robust to process variations. Toward this end, this work investigated the effect of alloy composition on the robustness of steels consolidated via laser-directed energy deposition (L-DED). Ultra-high-strength low-alloy steel (UHSLA) and pure iron powders were mixed in-situ to produce 10 compositions containing 10-100% UHSLA by mass. JMatPro material simulations roughly predicted phases and mechanical properties. Two sets of experiments were used to evaluate the sensitivity of as-built hardness (all 10 compositions) and tensile properties (5 select compositions) to process …

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Understanding Heterogeneous Nucleation In Iron Alloys From First Principles: A Review And Discussion, Semen Naumovich Lekakh Jan 2025

Understanding Heterogeneous Nucleation In Iron Alloys From First Principles: A Review And Discussion, Semen Naumovich Lekakh

Materials Science and Engineering Faculty Research & Creative Works

Heterogeneous nucleation during solidification plays a key role in structure formation of different types of iron-based alloys, including steels and cast irons. A review summarizes the novel theoretical methods which were used to understand the nature of heterogeneous nucleation in iron-based alloys. An ab initio simulation of atomic adsorption was used to predict the activity of heterogeneous nuclei, and the thermodynamic methods were applied to design conditions for desired precipitate formation in the iron melts. A high-resolution TEM study of individual nucleus and statistics of nuclei family, obtained from an automated SEM/EDX analysis, illustrates a possibility to design processes of …

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High-Temperature Performance Of Alloyed Cast Irons And Cr/Ni Austenitic Steels—An Overview And Discussion, Simon N. Lekakh, Mei Li, Larry Godlewski Jan 2025

High-Temperature Performance Of Alloyed Cast Irons And Cr/Ni Austenitic Steels—An Overview And Discussion, Simon N. Lekakh, Mei Li, Larry Godlewski

Materials Science and Engineering Faculty Research & Creative Works

Fe-based cast alloys, including cast irons and steels, have been used in service at a wide range of mechanical and thermal load in oxidizing environment. Special alloying practices can be used to improve high temperature performance of Fe-based cast alloys in an oxidizing atmosphere. At elevated temperatures, alloying elements can produce a protective interface layer which prevents oxidant penetration into the metal matrix. However, a combination of thermo-mechanical loads along with surface oxidation can decrease the materials integrity by destroying the stable protected interface limiting the range of working parameters and lifetime performance of the material. This overview aims to …

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Flexural Strength Of (Hf,Nb,Ta,Ti,Zr)B2–(Hf,Nb,Ta,Ti,Zr)C High-Entropy Dual-Phase Ceramics, Rubia Hassan, William G. Fahrenholtz, Gregory E. Hilmas, Jeremy Watts Jan 2025

Flexural Strength Of (Hf,Nb,Ta,Ti,Zr)B2–(Hf,Nb,Ta,Ti,Zr)C High-Entropy Dual-Phase Ceramics, Rubia Hassan, William G. Fahrenholtz, Gregory E. Hilmas, Jeremy Watts

Materials Science and Engineering Faculty Research & Creative Works

The room and elevated temperature flexural strengths were measured for (Hf,Nb,Ta,Ti,Zr)B2–(Hf,Nb,Ta,Ti,Zr)C high-entropy dual-phase ceramics. The fracture of ceramics originated from two distinct flaw populations that were either surface defects introduced during specimen preparation or volume defects introduced during processing. The average strength at room temperature was 638 ± 94 MPa with individual bars strengths as high as ∼800 MPa. At 1800°C, average strength increased to 786 ± 265 MPa with individual bar strengths as high as ∼1050 MPa. Above 1800°C, creep dominated resulting in deformation of the bars without fracture. The fracture mode changed from completely trans granular at room …

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Development Of Stalling Detection Algorithms And Operator Behavior Models For Evaluating Hydraulic Excavator Performance, Mateo Fernando Montenegro Defaz Jan 2025

Development Of Stalling Detection Algorithms And Operator Behavior Models For Evaluating Hydraulic Excavator Performance, Mateo Fernando Montenegro Defaz

Masters Theses

This study aims to develop a reliable algorithm for stalling detection and investigate how operator behaviors impact the truck-loading process, focusing on swing and bucket rotations. While the study of excavator digging conditions and equipment performance is well understood, describing stalling from telemetry data and the influence of operators’ behavior on overall system efficiency remain underexplored. This study seeks to: (i) develop a reliable algorithm for stall detection by analyzing key operational variables such as velocity and angles; (ii) implement statistical and machine learning techniques, specifically a Support Vector Machine (SVM) classification algorithm, to differentiate between ideal and non-ideal digging …

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Quantifying Deviation Of Elasticity In The Quasi-Elastic Domain Of Granular Soils, Wen Deng, Yufan Jin, Pingxin Xia, Qingqing Fu, Xiong Xia, Xiaoxia Guo Jan 2025

Quantifying Deviation Of Elasticity In The Quasi-Elastic Domain Of Granular Soils, Wen Deng, Yufan Jin, Pingxin Xia, Qingqing Fu, Xiong Xia, Xiaoxia Guo

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The absence of purely elastic properties in granular soil is attributed to the reversible sliding that occurs between particles during the loading–unloading cycle, leading to the dissipation of energy through friction. Instead of the strictly elastic domain, we opt for a quasi-elastic domain to examine elastic behavior within the confines of elastic theory. Within this quasi-elastic realm, the response deviates to some extent from the idealized pure elastic behavior posited by the elastic theory. As a result, the elastic constitutive relations applied to granular materials are no longer strictly accurate and may exhibit deviations. With the aim of exploring the …

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Extending The Applicability Of Thermal Protection System Ballistic Limit Equations Beyond The Testable Regime, William P. Schonberg, Michael D. Squire Jan 2025

Extending The Applicability Of Thermal Protection System Ballistic Limit Equations Beyond The Testable Regime, William P. Schonberg, Michael D. Squire

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Spacecraft use thermal insulation in their design, which is usually placed on their exterior. As such, it is susceptible to high-speed impacts by meteoroids and orbital debris, which can damage it to a point where the protection it offers is below acceptable limits. It is important to be able to characterize expected levels of damage stemming from such high-speed impacts. In this paper, we extend the applicability of a previously developed ballistic limit equation (BLE) for one such thermal insulation material using the results of a series of Smooth Particle Hydrodynamics Code (SPHC) impact simulations at velocities in excess of …

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