Engineering Commons^™

Monitoring And Control Of Coal Dust Exposure Using Low-Cost Pm Sensors And Computational Fluid Dynamics, Nana Kobina Amoako Amoah

Doctoral Dissertations

"Overexposure to respirable coal mine dust has been linked to causing serious health problems including coal workers pneumoconiosis (CWP) and chronic massive fibrosis. The prevalence of these health problems has been on the increase since the 2000s due to increased exposure levels with roof bolter operators having the highest exposure levels. The currently used PDM3700 is too expensive, heavy and bulky which limits their use only for regulatory monitoring failing to measure miners’ personal exposure levels. Also, since roof bolter operators are more prone to elevated coal dust levels, the canopy air curtain (CAC) was developed to protect then high …

Modeling And Analysis Methods For Esd And Emi Problems, Xin Yan

Doctoral Dissertations

"Electrostatic discharge (ESD) failures and Electromagnetic interference (EMI) problems are becoming more critical in electronic devices and large systems. In this work, four studies are presented to model and analyze ESD and EMI problems.

First, a simplified physical-based model for deep-snapback transient voltage suppressors (TVS) is developed. While based on physics, the number of parameters and components is minimized. Results show that the proposed model captures the most important behaviors of the TVS response using a limited number of parameters, allowing the model to be tuned relatively easily using data obtained only from package-level transient and quasi-static measurements. Second, a …

Investigation Of Asphaltene Instability Under Gas Injection In Unconventional Reservoirs And Its Impact On Oil Recovery Performance, Mukhtar Elturki

Doctoral Dissertations

"Unconventional reservoirs, such as shale gas and tight oil formations, have become an important source of energy in recent years. However, these reservoirs often contain high levels of asphaltenes, which can lead to deposition and blockages in production wells and reduce the flow of hydrocarbons during gas enhanced oil recovery (GEOR) techniques. This study aims to experimentally evaluate the impact of miscible and immiscible carbon dioxide (CO₂) and nitrogen (N₂) on asphaltene deposition and its impact on oil recovery performance in unconventional shale reservoirs.

This research began with a comprehensive literature review and data analysis of GEOR methods in unconventional …

Melt Pool Feature Extraction, A State-Space Model And Spatial Layer-To-Layer Control For Powder Bed Fusion, Xin Wang

Doctoral Dissertations

"Powder Bed Fusion (PBF) is an Additive Manufacturing (AM) technique which can reduce material waste and is a fast-prototyping technique for complex geometries. However, the lack of consistent quality is a major problem in industrial applications. An InfraRed (IR) camera is a common tool to monitor a surface temperature field and melt pool morphology in PBF. With melt pool features from camera videos, manufacturing researchers use spatial feature maps to visualize defect locations and control researchers use layer-to-layer control to achieve more uniform melt pools and less defects.

Paper I presents a simulation method to characterize the effect of down-sampling …

A Human-Centered Framework For Oncological Healthcare System Modeling Applied To Mobile Radiation Delivery, Alex Price

Doctoral Dissertations

"Healthcare systems engineering is challenging due to the complexity, geographic expansiveness, inertial properties, and the heterogeneous sub-systems, with varying vested interests. Additionally, humans comprise many of the forms and functions, and are independent, with resistance and uncertainty in their decision-making that adds complexity. Human-centered systems modeling approaches are therefore needed to capture this unique aspect of a healthcare system and to enhance understanding of emergent healthcare properties. This dissertation focuses on integrating systems modeling within healthcare and emphasizes the importance of incorporating human decision-making. Moreover, the incorporation of a human-centered approach yields particularly valuable insights into the decision-making processes that …

Low-Shrinkage Fiber-Reinforced Concrete For Infrastructure Construction And Rehabilitation, Jingjie Wei

Doctoral Dissertations

"The aim of this study is to develop two classes of low-shrinkage high-performance concrete (HPC): fiber-reinforced super workable concrete (FR-SWC) for infrastructure construction and fiber-reinforced self-consolidating concrete (FR-SCC) for repair applications. HPC with excess content of shrinkage mitigation materials (SMMs), including shrinkage-reducing admixture (SRA), superabsorbent polymer (SAP), and expansive agent (EA) has a detrimental effect on mechanical performance. These classes of HPC were optimized to reduce shrinkage, enhance mechanical properties, and improve durability. The effect of fiber type (macro synthetic fiber, MSF; 5D steel fiber, 5D; 80% 3D + 20% short steel fibers; STST), SMMs, and plastic viscosity on bond …

The Comprehensive Study Of High Viscosity Friction Reducers In High-Tds And High-Temperature Environments, Xiaojing Ge

Doctoral Dissertations

"High viscosity friction reducers (HVFRs) have been recently gaining more attention and increasing in use, not only as friction-reducing agents but also as proppant carriers. Reusing of produced water has also been driven by both environmental and economic benefits. Currently, most friction reducers on the market are anionic friction reducers, which are fully compatible with most produced water with low to medium level of Total Dissolved Solids (TDS) but show a significant drop at high TDS conditions in term of their friction reduction performance in most cases. On the contrary, cationic friction reducers are believed to have better TDS tolerance …

Material Models For Simulation Of Steel Hot Rolling Process Using Experimentally Determined Properties At Elevated Temperatures And Strain Rates, Siva Sai Krishna Dasari

Doctoral Dissertations

"Hot rolling is one of the most important and complex process that includes large material deformation, different contact conditions, complex geometries and different temperature gradients along with micro structural changes such as viscoplasticity, dynamic recrystallization, and static softening. In the present work, the viscoplasticity, damage evolution, static softening and void closure of alloyed metal during hot rolling process was numerically investigated. Gleeble^TM hot compression and double hit tests were performed to provide experimental stress-strain curves at recrystallization temperatures and at different strain rates. Johnson-Cook viscoplastic model was calibrated using experimental stress-strain curves. Static softening model was developed at varying …

Additive Manufacturing Of Steel And Aluminum Structures: Modeling And Experiments, Manoj Kumar Reddy Rangapuram

Doctoral Dissertations

"Additive manufacturing (AM) is defined as the process of joining materials to make objects from three-dimensional model data. Complex geometries can be easily manufactured compared to conventional subtractive methods with more freedom and flexibility in the design process. As the demand for AM process increased, it has become critical to understand the process and various parameters that constitute in affecting the quality of the manufactured part. Conducting experiments can be time intensive and costly to optimize a process. Modeling can be used as an aid to optimize, examine, and predict the process outcome.

The objective of this study is (i) …

Integrated Study Of Heat Transfer And Local Gas Dynamics In A Pebble Bed Very High Temperature Nuclear Reactor Using Advance Measurement Techniques, Muhna N. Alshammari

Doctoral Dissertations

"The aim of this study, pebbles of diameter of 5 cm and a pebble-to-diameter ratio (aspect ratio) of 6 were used. In part I, the local gas velocities were studied at different radial and axial locations in the pebble bed using a sophisticated hot wire anemometry (HWA) technique, which was supported with a novel probe-protector case to protect the fragile probe, allowing the measurements to be taken between the pebbles for the first time. The local gas velocities were found to be significantly higher in the near wall region due to the higher void fractions in the near-wall region, compared …

Effects Of Electron Beam Irradiation On Crmnv And Crmntiv High Entropy Alloys: Nano-Mechanical, Structural, And Thermodynamic Perspectives, N. A. Sultana, Y. S. Mohammed, S. J. Pendleton, J. Vennekate, G. Ciovati, X. Li, H. Baumgart, A. A. Elmustafa

Mechanical & Aerospace Engineering Faculty Publications

Beam exit windows are crucial components of any particle accelerator as they provide an interface between the beamline vacuum and target material at atmospheric media. For high beam power machines, special materials and designs are required to withstand high radiation and mechanical loads, while minimizing energy loss during transition and maximizing window lifetime. This research investigates the impact of electron beam exposure to bulk CrMnV and CrMnTiV high entropy alloys (HEAs) with the primary goal of identifying suitable candidate materials for the design of robust and durable exit window settings. The selection criteria include intrinsic characteristics, power dissipation, and mechanical …

Prediction Of Anomalous Events With Data Augmentation And Hybrid Deep Learning Approach, Ahmed Shoyeb Raihan

Graduate Theses, Dissertations, and Problem Reports (ETD)

In this study, we propose a novel anomaly detection framework designed specifically for Multivariate Time Series (MTS) data, addressing the prevalent challenges in analyzing such complex datasets. The detection of anomalies within MTS data is notably difficult due to the complex interplay of numerous variables, temporal dependencies, and the common issue of class imbalance, where one category significantly outnumbers another. Traditional deep learning (DL) approaches often fall short in simultaneously tackling these issues. Our framework is designed to address these challenges through a two-phased approach. Phase I employs Conditional Tabular Generative Adversarial Networks (CTGAN) to create strategic synthetic data, setting …

High-Pressure Ignition And Flame Propagation – An Experimental And Numerical Study, James Shaffer

Graduate Theses, Dissertations, and Problem Reports (ETD)

The next generation of advanced combustion devices is being developed to operate under ultra-high-pressure conditions, to improve combustion efficiency and reduce pollutant emissions. However, at such extreme conditions, flame tends to become unstable, and measurement of fundamental properties becomes challenging. The laminar burning speed ( ) is among those properties, as it is required for the validation of kinetic models and the modeling of turbulent combustion. One potential method to resolve this issue and achieve measurement at very high pressures (i.e., 20-50 atm), is focusing on ignition affected region. The flame kernel in this region is more resistant to perturbations …

Joint Learning Of Unknown Safety Constraints And Control Policies In Reinforcement Learning, Lunet Abiye Yifru

Graduate Theses, Dissertations, and Problem Reports (ETD)

Reinforcement learning (RL) has revolutionized decision-making across a wide range of domains over the past few decades. Yet, deploying RL policies in real-world scenarios presents the crucial challenge of ensuring safety. Traditional safe RL approaches have predominantly focused on incorporating predefined safety constraints into the policy learning process. However, this reliance on predefined safety constraints poses limitations in dynamic and unpredictable real-world settings where such constraints may not be available or sufficiently adaptable. Bridging this gap, we propose a novel approach that concurrently learns a safe RL control policy and identifies the unknown safety constraint parameters of a given environment. …

Evaluation Of 50’ Frp Truss Bridges With Timber Decks, Maxwell Browning Carey

Graduate Theses, Dissertations, and Problem Reports (ETD)

Fiber-reinforced polymer (FRP) composites have become mainstream structural materials and are being utilized in many different structural applications because of their outstanding thermos-mechanical properties and other characteristics. These characteristics include exceptional corrosion resistance, energy absorption, durability, high strength-to-weight, stiffness-to-weight ratios, and others. Also, FRP composites are cost effective especially when accounting for the service life of such a material.

In this study, testing and analysis were performed at both the component as well as a structural system levels. Herein, two FRP truss bridges of different widths with 50 ft. spans underwent extensive testing and analysis in accordance with AASHTO specifications. …

Milk Collection Problem: Integrating The Traveling Salesman And Set Covering Problem - A Case Study In West Virginia, Usa, Md Rabiul Hasan

Graduate Theses, Dissertations, and Problem Reports (ETD)

Route determination for perishable products is complex due to its unique characteristics, such as limited shelf-life regulatory requirements, or possibility of getting damaged. This research investigates a novel problem of collecting raw milk from a rural network of dairy farms. The research problem is grounded in a real scenario of milk collection in West Virginia, USA. The milk in this scenario is produced by small farms incapable of realizing transportation economies of density out in mostly rural areas throughout the state. Maximum coverage area and milk processing overhead costs are used to identify suitable locations for intermediate milk collection centers …

Far-Field Passive Wireless Sensors Composed Of Electroceramic Materials For Harsh Environment Applications, Kevin M. Tennant

Graduate Theses, Dissertations, and Problem Reports (ETD)

The demand for high temperature sensing technologies in industrial applications has been steadily increasing, driven by the need for precise monitoring and control in extreme environments. This thesis presents an investigation into the development and optimization of passive wireless sensors for high temperature sensing applications. The research focuses on overcoming the challenges associated with traditional sensing methods by leveraging passive wireless sensor technology, offering advantages such as reduced complexity, improved reliability, and enhanced flexibility.

A passive wireless high temperature sensor for far-field applications was developed for stable temperature sensing up to 1000 °C. The goal is to leverage the properties …

Low Power Remote Sensing System For Ceramic Thermocouples, Syed Khaleduzzaman

Graduate Theses, Dissertations, and Problem Reports (ETD)

The ceramic thermocouple sensor is a promising alternative to traditional thermocouple due to their corrosion resistance and cost-effective manufacturing. Currently, no electronic Interface or Integrated Circuit solution is commercially available which can be used to interface these thermocouples at low-cost and low power for accurate temperature measurement. An electronic system is needed to use these ceramic sensors which consumes less amount of power for an extensive period of time with remote monitoring option.

This thesis proposes a low-power electronic remote sensing system that works for ceramic thermocouples. The system consists of three parts. They are battery-operated sensor node electronic circuit, …

Investigation Of Synergistic Effect Between Polystyrene And Polyethylene Under Conventional Thermal Heating And Microwave Heating, Thang Luong

Graduate Theses, Dissertations, and Problem Reports (ETD)

Single-use plastics (Low Density Polyethylene, LDPE; Polystyrene, PS; Polypropylene, PP) are increasingly used in the modern world, with their usage growing every year. An effective method to manage the resulting waste is urgently needed, as landfilling and incineration have proven harmful to the environment in the long term. Mechanical recycling may not maintain the desirable characteristics of the single-use plastics through several cycles. Pyrolysis emerges as a promising approach to address plastic waste. Given that single-use plastic waste often comes in a mixture, combining plastic in the feedstock is a viable solution to effectively convert these polymers altogether to gain …

Application Of Predictive Control Strategies For Water-Gas Shift Membrane Reactors Using Data-Driven Models, Bernardo De Oliveira Vecchio

Graduate Theses, Dissertations, and Problem Reports (ETD)

As demand for more efficient processes keeps rising and more restrictive environmental legislation requires higher levels of both yield and purity, the process industry has now, more than ever, been looking for new ways to achieve these goals. One approach has been the implementation of Process Intensification (PI). PI aims to combine multiple unit operations into a single one, promoting efficiency gains on multiple levels. This combination, however, leads to complex process dynamics, and controlling such processes, particularly when setup as multi-input-multi-output (MIMO) systems, presents a great challenge due to highly interactive complex process dynamics and the imposition of many …

Venus Balloon Localization: A Map-Aided Navigation Approach Supported By A Single-Satellite, Heath Scott Cottrill

Graduate Theses, Dissertations, and Problem Reports (ETD)

Although Venus and Earth began as twins, possessing comparable size, mass, and composition, past exploration missions have revealed that Venus is now hellishly hot, devoid of oceans, and enveloped in a carbon dioxide-filled atmosphere. To understand when and why this evolutionary divergence occurred, further exploration is required. Today, there is a growing interest in the use of aerial platforms to circumvent the harsh conditions at the surface, which limit the lifetime of landed instruments. In this concept, a single balloon, propelled by the ambient wind field, would operate in the atmosphere at an altitude between 50 and 70 km, where …

Data-Driven Modeling Of Oxygen Kinetics In La0.6sr0.4co0.2fe0.8o3−Δ (Lscf) For High-Temperature Reduction Of Co2 In An Electrolysis Cell, Ferron Campbell

Graduate Theses, Dissertations, and Problem Reports (ETD)

Electrolysis systems are critical to several societal applications, particularly energy storage and conversion. Developing these systems requires a detailed knowledge of the chemistry and thermodynamics of the materials used in the electrolysis cell. This work focuses on using embedded scientific machine learning as an efficient way to build an interpretable model for the reaction and transport kinetics in the LSCF electrode, whose performance directly influences the electrolysis system’s performance. The models developed in this study are trained using the publicly available machine learning package, FoKL-GP. This package incorporates a robust Gibbs sampler that employs a forward variable selection process to …

Laser Deposition Additive Manufacturing Of Multi-Material And Metal-Ceramic Composite Structures, Manikanta Grandhi

Graduate Theses, Dissertations, and Problem Reports (ETD)

The increasing performance requirements of modern industrial systems, coupled with the imperative for decarbonization, necessitate a fundamental rethinking of metallic component design and manufacturing. Traditional materials, with their inherent limitations in property optimization, susceptibility to degradation, and weight constraints, are proving insufficient. Multi-material joining offers a potential solution, enabling designers to strategically integrate diverse materials with specific, tailored properties into single component. Functionally graded materials (FGMs) and oxide dispersion strengthened (ODS) materials are prime examples of this approach, delivering substantial improvements in wear resistance, thermal regulation, high-temperature resilience, and overall weight efficiency. However, conventional manufacturing approaches further exacerbate the limitations …

Machine Learning-Assisted Multiscale Simulation And Design Optimization Of Composite Jackets Under Low-Velocity Impacts, Masoud Mohammadi

Graduate Theses, Dissertations, and Problem Reports (ETD)

This research presents the development of a data-driven machine learning-assisted approach to simulate and optimize the design of composite materials subjected to low-velocity impacts. It focuses on a specific type of hybrid composite comprised of fiberglass and Kevlar fabrics stitched with Kevlar threads. The study begins by creating a multiscale finite element simulation for the composite under a low-velocity impact, which operates across three scales: microscale, mesoscale, and macroscale. This simulation accepts various inputs, such as different layer configurations and orientations, and provides impact outputs including maximum load and energy absorption capacity and displacement at failure.

Python and MATLAB scripts …

Weighted Effect Of Concentrated Cracking On The Structural Integrity Of Concrete Bridge Decks, Md Ala Uddin

Graduate Theses, Dissertations, and Problem Reports (ETD)

Concrete bridge decks are vital components of transportation infrastructure, yet their deterioration due to aging, environmental, and operational factors poses significant challenges to maintenance and safety. In the United States, approximately 9.1% of bridges require improvement, with millions of daily trips relying on structurally deficient bridges. Cracking is one of the most frequently observed defects on concrete bridge structures. Traditional bridge inspections evaluate cracks based on severity (crack width) and extent (crack area), combining these values with other performance indicators to assess overall bridge health. However, the effect of concentrated cracking in localized areas on bridge integrity remains largely unexplored. …

Impact Of Glottis Area On Airflow Dynamics In The Human Trachea Using A Simplified Stenosis Pipe Model, Amany M. Kamal, Momtaz Sedrak, Abouelmagd Abdelsamie

Trends in advanced sciences and technology

A complex transitional flow is produced in the larynx during air inhalation process, pivotal for fundamental comprehension and medical advancements in treatment methodologies. This study delves into the influence of the glottis region utilizing a simplified stenosis pipe geometry, examining two distinct cases: (1) the axisymmetric case and (2) the eccentric case. Reynolds-averaged Navier–Stokes equations with shear stress transport (SST) 𝑘 − 𝜔 turbulence model with intermittency transition activated with steady, Newtonian, and incompressible airflow have been used. The analysis underscores the significant impact of the eccentricity on the velocity by increasing 0.6% comparing with axisymmetric case, also particularly affecting …

Fundamentals Of Vehicle Modeling For Mobility And Maneuver, Jordan Whitson

All ETDs from UAB

The direction of research for off-road ground vehicles is an ever-growing interdisciplinary field. The strategies and modeling methods range from simple terramechanics mathematical models to complex terramechanics that involve the use of high-performance computing (HPC) systems with varying vehicle metric and performance analysis and information extraction. Current advanced methods based on terrain properties and dynamic models utilize conventional performance metrics that have been supported through decades of research. As automated driving systems (ADS) and unmanned ground vehicles (UGVs) research and development progress, more complexities are unraveled and present the need for novel directions of research. Whereas on-road vehicles have the …

3d Microtissue Model Of The Aged Ovarian Tumor Microenvironment, Peyton Clark

All ETDs from UAB

Ovarian cancer is the 5th leading cause of cancer deaths for women, primarily due to treatment resistant and/or recurrent disease. Most cases of ovarian cancer are not diagnosed until distant metastases have formed, which drastically reduces overall survival. The median age at diagnosis is 63 and most cases occur in patients who are peri- and post-menopausal. There is a critical gap between the clinical presentation of ovarian cancer and the preclinical models used to study the disease. Most preclinical in vivo investigations use mice who are between 6 and 12 weeks old, which corresponds to roughly a 20-year-old human. Therefore, …

Comparative Enzymatic Analysis Of Different Isoforms Of Group A Streptococcal Bacteriophage H4489a Hyaluronidase, Urvi Prakash Rawal

All ETDs from UAB

The Hyaluronate Lyase derived from Group A streptococcal bacteriophage H4489A gene (HylP) is known for cleaving the glycosidic bonds of high molecular weight hyaluronic acid (HMWHA), a substance often overexpressed in certain types of cancer cells. This enzymatic action produces HA oligosaccharides. Previous research, conducted by our team, has demonstrated that these oligosaccharides play a significant role in reducing the invasion, migration, and proliferation of breast cancer cells. This effect occurs through the disruption of Erk1/2 activation and RhoA expression. This bacteriophage hyaluronate lyase (HylP), a 40kDa protein, possesses a unique collagen-like sequence, consisting of 30 amino acids in a …

Energy And Exergy Analysis Of Multi-Stage Axial Flow Compressor: Degree Of Reaction, Inlet Temperature, And Pressure Ratio Impacts, Mohamed Abdelaal, Rafea Mohamed Abd El-Maksoud, Nazih Noaman Bayomi

Trends in advanced sciences and technology

This paper presents a comprehensive energy and exergy analysis of a multistage axial compressor, specifically examining a 12-stage model to assess the impact of varying inlet temperatures, degrees of reaction, and pressure ratios. This study contributes to the ongoing efforts to optimize compressor technology for better performance and reduced energy consumption, emphasizing the importance of parameter selection in achieving desired operational outcomes. In the current research, the performance of the axial compressor was studied from an energy and exergy point of view while changing the parameters previously mentioned in detail as stages and rotors due to the lack of previous …