Engineering Commons^™

The Wound Healing And Antibacterial Properties Of Mesenchymal Stromal Cell Extracellular Matrix Nanoparticles, Emily N. Wandling

Theses and Dissertations

Treatments for acute respiratory distress syndrome (ARDS) are still unavailable and the prevalence of the disease has only increased due to the Covid-19 pandemic. Mechanical ventilation regiments are still utilized to support declining lung function, but they also contribute to lung damage and increase the risk of bacterial infection. The anti-inflammatory and pro-regenerative abilities of mesenchymal stromal cells (MSCs) have shown to be a promising therapy for ARDS. We propose to utilize the regenerative effects of MSC secretome and the extracellular matrix (ECM) into a nanoparticle. Our mouse MSC (MMSC) ECM nanoparticles were characterized using size, zeta-potential, and mass spectrometry …

Wifi Sensing At The Edge Towards Scalable On-Device Wireless Sensing Systems, Steven M. Hernandez

Theses and Dissertations

WiFi sensing offers a powerful method for tracking physical activities using the radio-frequency signals already found throughout our homes and offices. This novel sensing modality offers continuous and non-intrusive activity tracking since sensing can be performed (i) without requiring wearable sensors, (ii) outside the line-of-sight, and even (iii) through the wall. Furthermore, WiFi has become a ubiquitous technology in our computers, our smartphones, and even in low-cost Internet of Things devices. In this work, we consider how the ubiquity of these low-cost WiFi devices offer an unparalleled opportunity for improving the scalability of wireless sensing systems. Thus far, WiFi sensing …

Pms And Gas Pollutants Removal By Electret Filter Media And Metal-Organic Frameworks (Mofs), Yu Zhang

Theses and Dissertations

Indoor air quality (IAQ) has been becoming a major concern worldwide because statistical data showed that the indoor concentrations of gas pollutants, e.g., volatile organic compounds (VOCs) and particulate matters (PMs) are often 2–5 times higher than that of outdoors. Especially, people spend 87% of their time indoors and increasing to more than 90% during COVID-19 pandemic. The high concentration of these indoor air pollutants is mainly due to the reduced air exchange rate for the design of energy-efficient building construction and the increased usage of furnishings, glues, paints, furnaces, etc., leading to VOC outgassing and particle emission. Evidence has …

A Sustainable Ultrafiltration Of Sub-20 Nm Nanoparticles In Water And Isopropanol: Experiments, Theory And Machine Learning, Jie Mcatee

Theses and Dissertations

This research focused on ultrafiltration (UF) for particles down to 2 nm against membranes with larger pore size in water and IPA, which has the potential to save up to 90% of energy. This study developed electrospray (ES) - scanning mobility particle sizer (SMPS) method to fast and effective measure retention efficiencies for small particles (ZnS, Au and PSL) on polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF) and polycarbonate (PCTE) in different liquids. Theoretical models that could quantitatively explain the experimental results for small particles in medium-polarity organic solvents were also developed. Results showed that the highest efficiency was up to ~80% …

Synthesis And Application Of Redox-Active Covalent Organic Frameworks In Rechargeable Batteries, Mohammad K. Shehab

Theses and Dissertations

Synthesis and Application of Redox-Active Covalent Organic Frameworks in Rechargeable Batteries

Mohammad K. Shehab

Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States

Abstract

In recent years, lithium-ion batteries (LIBs) have been considered the dominant energy storage devices for portable electronics and electric vehicles due to their high energy density, low self-discharge rate, and long cycle life. In LIBs, the traditional positive electrodes employed are mainly derived from metal-containing inorganic compounds composed of cobalt, iron, nickel, or manganese (LiCoO₂, LiMn₂O₄, and LiFePO₄) coupled with graphite as the negative electrode. Despite …

Model Based Systems Engineering Approaches To Chemicals And Materials Manufacturing, Quang Le

Theses and Dissertations

Model-based systems engineering (MBSE) is part of a long-term trend toward model-centric approaches adopted by many engineering disciplines. This work establishes the need for an MBSE approach by reviewing the importance, complexity, and vulnerability of the U.S. chemical supply chains. The origins, work processes, modeling approaches, and supporting tools of the systems engineering discipline (SE) are discussed, along with the limitations of the current Process Systems Engineering (PSE) framework. The case is made for MBSE as a more generalizable and robust approach. Systems modeling strategies for MBSE are introduced, as well as a novel MBSE method that supports the automation …

Mechanisms Of Emulsion Destabilization: An Investigation Of Surfactant, Stabilizer, And Detergent Based Formulations Using Diffusing Wave Spectroscopy, Jordan N. Nowaczyk

Theses and Dissertations

Conventional approaches for studying emulsions, such as microscopy and macroscopic phase tracking, present challenges when it comes to establishing detailed mechanistic descriptions of the impact of emulsifier and stabilizer additives. Additionally, while a combination of sizing methods and macroscopic phase tracking can provide insights into droplet size changes and concentration, the use of multiple measurements can be cumbersome and error-prone. It is the focus of this work, to present a new method for studying water in oil (W/O) emulsions that involves using diffusing wave spectroscopy (DWS) to examine the impact of three different surface stabilizing additives at varying concentrations. By …

Portable Robotic Navigation Aid For The Visually Impaired, Lingqiu Jin

Theses and Dissertations

This dissertation aims to address the limitations of existing visual-inertial (VI) SLAM methods - lack of needed robustness and accuracy - for assistive navigation in a large indoor space. Several improvements are made to existing SLAM technology, and the improved methods are used to enable two robotic assistive devices, a robot cane, and a robotic object manipulation aid, for the visually impaired for assistive wayfinding and object detection/grasping. First, depth measurements are incorporated into the optimization process for device pose estimation to improve the success rate of VI SLAM's initialization and reduce scale drift. The improved method, called depth-enhanced visual-inertial …

Investigating Tgf-Β1 And Fibronectin Signaling In Low Oxygen Environments, Caitlin E. Williams

Theses and Dissertations

Breast cancer is the second leading cause of death in women, second to lung cancer. It’s one of the most well-known cancers, with almost 300,000 new cases estimated to be diagnosed in 2023. Breast cancer often begins in ductal epithelial cells, and these cells will typically undergo a cellular transformation process known as epithelial-mesenchymal transition (EMT) in early stages. Breast cancer becomes deadly when it reaches a metastatic stage. As a part of the metastatic process, transformed cells will conduct remodeling of the extracellular matrix (ECM) to allow for migration of an otherwise non-migratory cell type.

As dense tumors form, …

Real-Time Motion Controller For Human-Robot Teams Utilizing Artificial Potential Fields, Gabriella Graziani

Theses and Dissertations

This thesis presents a real-time robotic motion control system for human-robot teams. The framework utilizes artificial potential fields (APFs) to guide robotic agents towards a “goal” agent while navigating around “obstacle” agents; these goals and obstacles are also dynamic agents with their own set of tasks. This system is also developed for a live-programming environment, where a controlling agent updates the tasks of all agents within the system at any time during the system’s runtime. This motion controller was created and tested for a human-robot choreographic team. After the controller was fully integrated on a Trossen Robotic LoCobot Wx200 robotic …

Numerical Study Of Sediment Suspension Affected By Rigid Cylinders Under Unidirectional And Combined Wave-Current Flows, Sha Lou, Xiaolan Chen, Shengyu Zhou, Gangfeng Ma, Shuguang Liu, Larisa Dorzhievna Radnaeva, Elena Nikitina, Irina Viktorovna Fedorova

Civil & Environmental Engineering Faculty Publications

Sediment transport modeling for flows with cylinders is very challenging owing to the complicated flow–cylinder–sediment interactions, especially under the combined wave-current flows. In this paper, an improved formulation for incipient sediment suspension considering the effect of cylinder density (i.e., solid volume fraction) is employed to simulate the bottom sediment flux in the flow with cylinders. The proposed model is calibrated and validated using laboratory measurements under unidirectional and combined wave-current flows in previous studies. It is proved that the effects of cylinders on sediment suspension can be accounted for through a modified critical Shields number, and the proposed model is …

Are Ride-Hailing Services Safer Than Taxis? A Multivariate Spatial Approach With Accomodation Of Exposure Uncertainty, Guocong Zhai, Kun Xie, Hong Yang, Di Yang

Civil & Environmental Engineering Faculty Publications

Despite many research efforts on ride-hailing services and taxis, limited studies have compared the safety performance of the two modes. A major challenge is the need for reliable mode-specific exposure data to model their safety outcomes. Moreover, crash frequencies of the two modes by injury severities tend to be spatially and inherently correlated. To fully address these issues, this study proposes a novel multivariate conditional autoregressive model considering measurement errors in mode-specific exposures (MVCARME). More specially, a classical measurement error structure is used to accommodate the uncertainty of mode-specific exposures estimated, and a multivariate spatial specification is adopted to capture …

Experimental Evaluation Of Micro-Epidermal Actuators On Flexible Substrates, Courtney D. Bradley

Graduate Research Theses & Dissertations

Does embedding actuators in a flexible substrate increase their performance in hearing aids? What are the differences in damping experienced by actuators of different diameters and at different locations? At what frequency is peak acceleration achieved and what role does the size of the actuator and embedding it in a flexible substrate play? These questions will form the basis of this thesis. This work was done to develop a small non-invasive Band-Aid-©-like hearing aid. The novelty of this device requires a detailed analysis of piezoelectric actuators. This is a continuation of past students’ work on the topic. The main parameters …

Coulomb Blockade-Mediated Field Emission Sources Using Ultra-Nanocrystalline Diamond, Jevin Jensen

Graduate Research Theses & Dissertations

Coulomb Blockade effects in field emission provide interesting means of achieving brighter electron sources for numerous applications, ranging from vacuum electronics to the next generation of electron beam technology. Microelectronics cleanroom methods are presented in this thesis for production of field emission sources moderated by the Coulomb Blockade. The use of common processes is an essential step toward widespread experimentation with Coulomb Blockade-mediated field emission apparatuses. The main feature to be explored is the use of nano-diamond films for their potential applicability for this desired outcome. Ultra-Nanocrystalline Diamond is used in two different ways to achieve this, both as a …

Surface Modified Titanium And Doxycycline Loaded Pcl/Plga Nanofibers For Improved Cellular Interaction And Biocompatability, Dexter D. Kling

Graduate Research Theses & Dissertations

Biomaterials play an important role in modern medicine through their complexfunctionalities, as implants, grafts, and drug delivery systems. The addition of dopants and biomolecules in biomaterials offers unique solutions to common issues and provides new methods of improving overall health. In our work, we examined osteoblast cell interactions with titanium (Ti) after alkali treatment and deposition of magnesium (Mg) and iron (Fe). We also studied the antibacterial properties of doxycycline loaded polymeric nanofibers produced via electrospinning. To study the biological properties of surface-modified Ti, we first prepared commercially pure titanium samples by grinding and polishing, then performed alkali treatment in …

Part Design Geometry-Driven Toolpath Optimization For Additive Manufacturing Energy Sustainability Improvement, David Kolawole Somade

Graduate Research Theses & Dissertations

One of the most promising new manufacturing technologies in the past three decades isadditive manufacturing (AM), also commonly known as three-dimensional (3D) printing or rapid prototyping. The energy consumption problem in AM can be significant when it is adopted at the industrial scale or used under resource-restricted conditions. The energy consumption of an AM process is influenced by several factors including bed heating, filament extrusion, material infill, component cooling, etc. All these factors are further determined by the equipment and the toolpath for a specific printing task. Build orientation and tool-path direction are frequently used to optimize part and process …

Diffuse Scattering And 3d-∆Pdf Analyses: Order-Disorder Phase Transitions In (Sr1−Xcax)3rh4sn13 And Nano2, Puspa Upreti

Graduate Research Theses & Dissertations

Classification of structural phase transitions as being of the displacive or order-disorder types is usually done based on spectroscopic measurements performed above the transition. Transitions of the displacive type typically occur when soft phonon modes condense upon approaching the phase transition, whereas those of the order-disorder type are characterized by structures in which the atoms are located randomly above the phase transition at T* at the minima of a multiwell potential. In the ordered state, i.e., when T

We have performed single crystal x-ray scattering experiments and three-dimensional pair distribution functions (3D-∆PDF) analyses to understand the nature of phase transitions …

Mechanical Behavior Of Metallic Core-Shell Nanoparticles Under Compressive Loading, Phillip Tomich

Graduate Research Theses & Dissertations

Core/shell metallic nanoparticles have been shown to be a promising material type for additive manufacturing in the aerospace and automotive fields. Within additive manufacturing they will be used to accurately make an array of nanoparticles within the grains of metal matrix composites. This in turn will help to strengthen the material while remaining ductility and light weight. In this study, copper/aluminum core/shell nanoparticles are compressed under [100], [110], [111], and [112] directions to showcase their anisotropic material properties. Models of their individual counterparts were also investigated. There are no previous works showing the deformation mechanisms of copper/aluminum core/shell nanoparticles. Molecular …

Thermal Analysis Of Thermal Shield For Pip-Ii Ssr1 Cryomodule, Victor Aguado Rodriguez

Graduate Research Theses & Dissertations

Fermilab's PIP-II project plans to enhance the onsite accelerator into the world's most intense neutrino beam, bringing Fermilab into the next generation of particle accelerators. The five different types of cryomodules are vital parts of the PIP-II project and each requires numerous engineering analyses to prove operation. For example, the thermal shield of the Single Spoke Resonator-1 (SSR1) cryomodule required a thermal analysis to ensure the design was operating as intended before fabrication commenced. The thermal shield is cooled by the supercritical helium inside of the extrusion and must remain between 45 and 80 Kelvin. The main purpose of the …

Prioritized Object Detection Integrating Fuzzy Logic Risk Assessment And Planned Path., Khatereh Mohammadi

Graduate Research Theses & Dissertations

Nowadays, Autonomous Vehicles are in the spotlight as a response to the challenges stemming from population growth, worsening traffic congestion, and rising road accidents. Researchers and companies are concentrating on developing Automated Driving Systems (ADS) to tackle these issues.Of the various components that constitute an autonomous vehicle, perception plays a pivotal role, akin to the function of human eyes and the human brain. Therefore, ensuring precise and reliable perception within Autonomous Vehicles is paramount. This thesis is inspired by the principles of human perception, particularly on the road, and endeavors to replicate this process. Just as a human driver does …

A High-Precision Electron Emission Model: Computational Methods For Nanoscale Structures, Alister J. Tencate

Graduate Research Theses & Dissertations

The high-intensity, high-brightness and precision frontiers for charged particle beams are an increasingly important focus for study. Electron microscopy has demonstrated high quality beams from a single nanotip emitter, and cathodes of structured nanoscale arrays show promise as ultracold electron sources. Optimization of the cathode design for precision applications necessitates a detailed treatment of the interplay between the structure geometry, quantum mechanical emission mechanism, and electromagnetic interactions between the emitted electrons and the boundary interface. This dissertation details the numerical tools developed to simulate these processes efficiently with enough fidelity to be accurate even in the ultracold regime.

Conventional simulation …

Reconfigurable Microfluidic Circuits Through Modular Surface Driven Microfluidic Diode Valves, Selina Cervantes

Graduate Research Theses & Dissertations

In this thesis, we explore the rapidly evolving landscape of healthcare and diagnostics, shaped by the transformative impact of the COVID-19 pandemic. The focus of Point-of-care showcases innovative breakthroughs in microfluidics, capillary action, and lateral flow technology that are revolutionizing medical diagnostics. We delve into the mechanics of current assays, particularly in resource-limited settings. We then unveiled the introduction of a novel fluidic diode valve, designed to enhance lateral flow assays (LFAs) for point-of-care diagnostics. This diode design boasts a unidirectional flow mechanism, and our proof-of-concept experiments validate its potential for scalability, precise flow control, and applications in complex lateral …

Assessing A Byproduct Of The Cbd Ethanol Extraction Process For Potential As A Wood Finishing Product, Avani M. Flanagan

Masters Theses

Developments in regulations concerning the use of CBD products as therapeutic remedies have allowed the global cannabidiol (CBD) market to take off within the past five years. Despite producers of CBD oil wanting to optimize their methods and increase product yields, several waste streams still exist. During the winterization phase of the ethanol extraction process, CBD oil is cooled and filtered so the fats, waxes, and lipids from the Cannabis sativa plant can coagulate and be removed, creating a purer oil with higher potency but contributing to the 58% (crude weight) total loss that occurs throughout the process. The removed …

Physics Infused Lstm Network For Track Association Based On Marine Vessel Automatic Identification System Data, Tasmiah Haque

Graduate Theses, Dissertations, and Problem Reports (ETD)

In marine surveillance, a crucial task is distinguishing between normal and abnormal vessel movements to timely identify potential threats. Subsequently, the vessels need to be monitored and tracked until necessary action can be taken. To achieve this, a track association problem is formulated where multiple vessels' unlabeled geographic and motion parameters are associated with their true labels. These parameters are typically obtained from the Automatic Identification System (AIS) database, which enables real-time tracking of marine vessels equipped with AIS. The parameters are time-stamped and collected over a long period, and therefore, modeling the inherent temporal patterns in the data is …

An Artificial Neural Network Approach To Predicting Formation Stress In Multi-Stage Fractured Marcellus Shale Horizontal Wells Based On Drilling Operations Data, Moudhi Alawadh

Graduate Theses, Dissertations, and Problem Reports (ETD)

The distribution of the anisotropic minimum horizontal stress, both in horizontal and vertical directions, is necessary for effective hydraulic fracture treatment design in Marcellus Shale horizontal wells. Typically, the minimum horizontal stress can be estimated sonic logs. However, sonic log data is not commonly available for the horizontal Marcellus shale wells due to the complexity and cost. The objective of this research is to predict the anisotropic minimum horizontal stress by utilizing drilling parameters including depth, weight-on-bit (WOB), revolution per minute (RPM), standpipe pressure, torque, pump flow rate, and the rate of penetration (ROP). More specifically, artificial neural network (ANN) …

Leveraging Artificial Intelligence And Geomechanical Data For Accurate Shear Stress Prediction In Co2 Sequestration Within Saline Aquifers (Smart Proxy Modeling), Munirah Alawadh

Graduate Theses, Dissertations, and Problem Reports (ETD)

This research builds upon the success of a previous project that used a Smart Proxy Model (SPM) to predict pressure and saturation in Carbon Capture and Storage (CCS) operations into saline aquifers. The Smart Proxy Model is a data-driven machine learning model that can replicate the output of a sophisticated numerical simulation model for each time step in a short amount of time, using Artificial Intelligence (AI) and large volumes of subsurface data. This study aims to develop the Smart Proxy Model further by incorporating geomechanical datadriven techniques to predict shear stress by using a neural network, specifically through supervised …

Artificial Intelligence And Multi-Physics Approach For Electrocoagulation Parameter Selection, Adam Cotton

Graduate Research Theses & Dissertations

Proper treatment of wastewater is crucial to maintain the health of the public and avoid pollution of the environment. Methods like filtering and chemical coagulation have been utilized to treat wastewater, but they have significant limitations such as inefficient treatment of micro-size pollutants, generation of secondary contaminants, and high operation and maintenance costs. The electro-coagulation system which generates coagulants from low-cost aluminum electrodes under the application of a current has received strong attention as a promising water treatment system. However, the EC system has not been fully utilized yet due to lack of understanding and operation guidelines.

In this study, …

Analysis Of Localization Algorithms For Wireless Sensor Networks Using Binary Data, Alexander Joseph Hart

Graduate Research Theses & Dissertations

The detection, localization, and tracking of environmental and physical conditions can be accomplished using wireless sensor networks (WSNs). Recent advancements in sensors, processors, and wireless communications have improved the quality and acquisition speed of data in WSNs. However, the data gathered by a WSN is inherently random due to component and environmental variations. Thus, statistical signal processing algorithms are needed to analyze the random data in a robust way. Though many algorithms for the analysis of random data are established and available, they are problem-specific and must be adapted to the application. This thesis provides an analysis of established localization …

Strongly Correlated Electron Systems: Rare- And Alkaline-Earth Manganese- And Nickel-Based Perovskite Oxides, Elena Krivyakina

Graduate Research Theses & Dissertations

This work is an academic exploration of the capacity to manipulate the characteristics of strongly correlated electron systems, specifically transition metal perovskite oxides, through chemical substitutions and structural modifications. The high flexibility of the perovskites offers prospects for customizing materials with specific functionalities, thereby holding promise for the advancement of innovative technologies in diverse industries, ranging from electronics and energy to information storage and spintronics. My research focuses on a comprehensive overview of investigations I conducted on three specific compositions, namely alkalineand rare-earth manganese-based and nickel-based oxides, denoted as (Sr, Ba)(Mn, T i)O3−δ, (Y, T b)MnO3+δ, and (Sr, La)N iO3−δ. …

Analysis Of The Effect Of Surface Roughness In Additive Manufacturing On Thermo-Hydraulic Performance By Ml Models Supported By Physics-Based Modeling, Kaylen A. Platt

Graduate Research Theses & Dissertations

Heat exchangers (HX) are crucial components of thermal control systems which facilitate proper transfer of heat in systems such as nuclear reactors. This research focuses on the heat transfer-enhancing effect associated with turbulence in fluid flowing conduits. Turbulence can be induced at low flow rates when surface roughness is present on channel walls. Rough surfaces are typically regarded as a flawed product of the Additive Manufacturing (AM) process during the construction of Heat Exchangers. Machining surface finishes onto AM parts is a typical post-processing method used to remove the roughness. Thorough investigations have not yet been published on the effects …