Engineering Commons^™

Exploring The Electrochemical Performance Of Calcium-Ion Batteries With Novel Cathodes And Electrolytes, Paul Alexis Chando

Dissertations - ALL

The development of electric vehicles and energy storage devices are part of larger international efforts to create a sustainable future. Lithium-ion batteries have become crucial components to powering these technologies. However, the growing dependence of this singular battery chemistry to power an ever expanding landscape of technologies raises sustainability issues around lithium. Exploration of alternate battery chemistries have become part of research efforts to meet global energy demands. Calcium has emerged as one such battery system that could help alleviate stresses placed on lithium with its energy density and cost. Battery chemistries are unique, and each battery possesses its own …

Control And Estimation Of Unmanned Aerospace Vehicles In The Presence Of Constraints And Dynamic Uncertainties, Abhijit Dongare

Dissertations - ALL

In the first part of this dissertation, we consider the control of autonomous systems in the presence of pointwise-in-time state and control constraints. Firstly, we propose the attitude and pointing control of a rigid body in the presence of constraints. Artificial potentials are used to achieve desired tracking and avoid pointing direction constraints. The proposed control law ensures the asymptotic convergence to the desired attitude and pointing direction. Additionally, the control of driftless control-affine systems is also considered. The feedback system converges in a stable manner to the desired safe set in the state space, while avoiding the unsafe exclusion …

Unmanned Aerial Systems (Uas) Traffic Density Prediction And Multi-Agent Task Allocation, Chen Luo

Dissertations - ALL

In recent years, the field of Multi-Agent Systems (MAS) has garnered increasing attention. The essence of Multi-Agent Systems lies in orchestrating the coordination and collaboration of autonomous agents, endowing them with the ability to work collectively towards common goals. This characteristic makes MAS particularly germane in addressing the challenges posed by complex and dynamic environments, where theadaptability and decentralized decision-making of autonomous agents prove advantageous. To delve into the intricacies of MAS, three primary research directions have emerged. Firstly, we aim to develop a model rapidly and accurately to forecast future Unmanned Aerial Systems (UAS) traffic density patterns while simultaneously …

Structure And Morphology Of Photoreactive Monomer–Nanoparticle Mixtures Under Patterned Irradiation, Shreyas Pathreeker

Dissertations - ALL

Establishing processing–structure relationships is central to materials science. In this work, we seek answers to whether morphology can be controlled during Light–Induced Self–Writing (LISW) in polymer composite materials, and if yes, how? LISW is based on the ability of light to undergo divergence–free propagation in photoreactive media due to photopolymerization–induced rise in refractive index of the medium. Notably, LISW in polymeric materials has found use predominantly for the fabrication of optical waveguides but has not been explored in polymer–inorganic mixtures. Using through–mask projection which creates a spatially periodic array of optical beams, this work extends LISW to nanoparticle–monomer mixtures to …

Exploring The Biomedical Applications Of Polyurethane-Based Foams, Films, And Hydrogels, Anand Utpal Vakil

Dissertations - ALL

Shape memory polymers (SMPs) are a class of smart materials that can be temporarily stored in a deformed shape and can actively recover their original shape upon exposure to an external stimulus, such as heat, magnetic field, moisture, pH, light, or electric field. The ability of SMPs to change shape when required can be used for a wide range of applications, especially in the case of minimally invasive biomedical applications. In this work, polyurethane-based SMPs were explored for their use in tissue engineering, drug delivery, and wound healing applications.

In the second chapter, low density porous foams with tunable degradability …

Automatic Generation Of Near-Body Structured Grids, Yuyan Hao

Dissertations - ALL

Numerical grid generation has been a bottleneck in the computational fluid dynamics process for a long time when using the structured overset grids. Many current structured overset grid generation schemes like the hyperbolic grid generation method require significant user interaction to generate good computational grids robustly. Other grid generation schemes like the elliptic grid generation method take a significant amount of time for grid calculation, which is not desirable for computational fluid dynamics.

Herein a new grid generation method is presented that combines the hyperbolic grid generation scheme with the elliptic grid generation scheme that uses Poisson’s equation. The new …

Numerical Investigation Of The Effect Of Inlet Turbulence Intensity On A Bluff-Body Stabilized Flame At Near Blow-Off Condition, Amir Ali Montakhab

Dissertations - ALL

This thesis investigates the effect of a boundary condition on the dynamics of a bluff-body stabilized f lame operating near blow-off condition. Special emphasis is given to the effect of inlet turbulence intensity. This work is motivated by the understanding that more stringent regulations on fossil fuels generated emissions necessitate the design of combustion systems that operate at very fuel-lean conditions. Combustion at very lean conditions, however, induces flame instability that can ultimately lead to flame fluttering and eventual extinction. The dynamics of the flame at lean conditions can therefore be very sensitive to its boundary conditions. To better understand …

Switched Kinematic And Force Control For Lower-Limb Motorized Exoskeletons And Functional Electrical Stimulation, Chen-Hao Chang

Dissertations - ALL

Millions of people experience movement deficits from neurological conditions (NCs) that impair their walking ability and leg function. Exercise-based rehabilitation procedures have shown the potential to facilitate neurological reorganization and functional recovery. Lower-limb powered exoskeletons and motorized ergometers have been combined with functional electrical stimulation (FES) to provide repetitive movement, partially reduce the burden of therapists, improve range of motion, and induce therapeutic benefits. FES evokes artificial muscles contractions and can improve muscle mass and strength, and bone density in people with NCs. Stationary cycling is recommended for individuals who cannot perform load-bearing activities or have increased risks of falling. …

Targeted Mesenchymal Stem Cell Differentiation From Induced Pluripotent Stem Cells For Therapeutic Application, Tackla Winston

Dissertations - ALL

Over the past decade, mesenchymal stem cells have increasingly gained interest as a cell source for the treatment of a variety of diseases. This is because they play several roles in tissue homeostasis and regeneration, such as altering the immune response to limit inflammation, aiding tissue repair through the release of various proteins, cytokines and growth factors, or differentiating into functional cells in specific tissues. The interest in MSCs for biomanufacturing applications has resulted in the development of various protocols to differentiate them from pluripotent sources. These protocols, however, fail to account for the differences that exist between MSCs from …

Engineering Temporal And Spatial Complexity In Biomaterial Scaffolds For Cardiac Disease Modeling And Mechanobiology, Chenyan Wang

Dissertations - ALL

Temporal and spatial mechanical cues play an important role in heart development, function, and disease manifestation. A deeper understanding of cardiac mechanobiology is especially important for fundamental biology and clinical diagnosis or heart disease treatment. Currently, human induced pluripotent stem cells (hiPSCs) are widely used to build human cell or tissue models, but culturing them in a petri dish fail to recapitulate the mechanical complexity in the native heart. To create a mechanical environment with better pathophysiological relevance, biomaterial scaffolds are usually employed to mimic the mechanical cues originated from extracellular matrix (ECM) remodeling. The goal of this dissertation is …

Leveraging Isocyanate Chemistry For Low Cost And Highly Functional Hydrogels, Henry Beaman

Dissertations - ALL

The development of novel biomaterials is an important step in providing higher quality products for wound healing, drug delivery, and tissue engineering. Progress is consistently being made in the development of new polymers, yet new polymer systems are often expensive and/or involve complex multistep synthesis methods. These limitations could hinder the translation and scalability of functionalized materials. To address the issues of complex synthesis and high cost, we have devised strategies for polymeric modification using isocyanate chemistry. Isocyanates are used in the manufacturing of polyurethanes. Isocyanates are highly reactive with common functional groups, such as amines, hydroxyls, and carboxylic acids. …

Analysis Of Wireless Networks With Massive Connectivity, Mangqing Guo

Dissertations - ALL

Recent years have witnessed unprecedented growth in wireless networks in terms of both data traffic and number of connected devices. How to support this fast increasing demand for high data traffic and connectivity is a key consideration in the design of future wireless communication systems. With this motivation, in this thesis, we focus on the analysis of wireless networks with massive connectivity.

In the first part of the thesis, we seek to improve the energy efficiency (EE) of single-cell massive multiple-input multiple-output (MIMO) networks with joint antenna selection and user scheduling. We propose a two-step iterative procedure to maximize the …

Evaluation Of The Energetic Factors In Crystalline Pharmaceuticals Using Solid-State Density Functional Theory And Low-Frequency Vibrational Spectroscopy, Margaret P. Davis

Dissertations - ALL

Due to the importance of maintaining stable and effective pharmaceutical solid doses, it is critical to study the variety of solid forms that active pharmaceutical ingredients can adopt including polymorphs, hydrates, and cocrystals. In this work, low-frequency vibrational spectroscopies and rigorous quantum mechanical simulations are combined to provide a new technique for characterizing and investigating pharmaceutically relevant polymorphs, hydrates, and cocrystals as well as a series of model cocrystals. Low-frequency spectra in the sub-200 cm-1 range provide not only unique and characteristic spectra for all of the systems explored here but, along with X-ray structural parameters, they offer a way …

Advanced In Vitro Models For Studying Bone Physiology, Kairui Zhang

Dissertations - ALL

Bone is a highly calcified organic-inorganic composite tissue with complicated hierarchical structure. The presence of complex multi-cellular organization within opaque mineralized matrix makes it challenging to use conventional methods to study in vivo bone physiology even using model animals. To address this challenge, numerous in vitro models have been developed to study bone physiology under well-defined and repeatable experimental conditions although proving their physiological relevance remains a key challenge. This work aims to design and develop new in vitro models that better represent in vivo bone physiology with defined control over chemical and physical microenvironments, at low costs and high …

New Solid Polymer Electrolytes For Lithium, Sodium, And Calcium-Based Batteries, Francielli Silva Genier

Dissertations - ALL

The establishment of sustainable energy sources highly depends on efficient storage devices to guarantee a consistent power supply. The growing demand for lithium-ion batteries (LIBs) for this purpose, combined with concerns about lithium availability, has motivated the search for viable storage alternatives, such as sodium and calcium. While several studies have investigated different lithium-free liquid electrolytes, the transport of these alternative ions in their polymer counterparts remains understudied. The advantages of solid polymer electrolytes include the possibility of higher energy density in solid-state devices and the elimination of safety concerns associated with liquid electrolytes, such as flammability, leakage, and dendrite …

Exploring Passive Flow Control Techniques Applied To A Supersonic Multistream Rectangular Nozzle, Emma Dawn Gist

Dissertations - ALL

Passive control techniques are applied experimentally to examine different aspects of a supersonic multistream rectangular nozzle representing a modern airframe-integrated variable cycle engine. The flow is comprised of a core stream (M = 1.6) and bypass (M = 1.0) that merge behind a splitter plate and exit through a Single Expansion Ramp Nozzle (SERN) onto an aft-deck. Previous efforts for the nominal nozzle configuration have shown that an instability initiated at the splitter plate trailing edge (SPTE) influences the effectiveness of the third stream as a barrier for the aft-deck and persists through the entire do- main due to its …

Circular Reinforced Concrete Columns Damaged By Fire And Retrofitted With Cfrp And Steel Jacketing, Jia Xu

Dissertations - ALL

In recent decades, the post-fire behavior of reinforced concrete (RC) columns with normal and high-strength concrete has become an important research topic. Numerous studies have demonstrated that RC columns exhibit good fire resistance owing to the thermal properties of concrete. Therefore, reinforced concrete structures rarely collapse within a finite fire duration and can be successfully repaired. Along with the increasing number of skyscrapers, high-strength concrete (HSC) has played an equally important role as normal-strength concrete (NSC) in the industry. In this study, the thermal behavior of RC columns with NSC and HSC exposed to ISO 834 standard fire for various …

Transformational Leadership And The Adoption Of Sustainability And Asset Management Practices In Ground Transportation Organizations, Mohammad M. Bushahri

Dissertations - ALL

The unprecedented challenges the infrastructure domain has been facing for the past few decades are forcing the authorities and owners of relevant organizations, particularly within the ground transportation sector, to introduce more innovative measures and to mitigate risks by embracing and adopting sustainability and asset management practices. This study examined the relationship between transformational leadership and the embracing and adopting of sustainability and asset management practices in the U.S. ground transportation sector. Further, this study assessed the mediation effect of organizational innovation on the relationship between transformational leadership style and the leaders' perception in terms of adaptation of sustainability and …

Learning-Based Decision Making In Wireless Communications, Chen Zhong

Dissertations - ALL

Fueled by emerging applications and exponential increase in data traffic, wireless networks have recently grown significantly and become more complex. In such large-scale complex wireless networks, it is challenging and, oftentimes, infeasible for conventional optimization methods to quickly solve critical decision-making problems. With this motivation, in this thesis, machine learning methods are developed and utilized for obtaining optimal/near-optimal solutions for timely decision making in wireless networks.

Content caching at the edge nodes is a promising technique to reduce the data traffic in next-generation wireless networks. In this context, we in the first part of the thesis study content caching at …

Enhancing Grid Reliability With Phasor Measurement Units, Rui Ma

Dissertations - ALL

Over the last decades, great efforts and investments have been made to increase the integration level of renewable energy resources in power grids. The New York State has set the goal to achieve 70% renewable generations by 2030, and realize carbon neutrality by 2040 eventually. However, the increased level of uncertainty brought about by renewables makes it more challenging to maintain stable and robust power grid operation. In addition to renewable energy resources, the ever-increasing number of electric vehicles and active loads have further increased the uncertainties in power systems. All these factors challenge the way the power grids are …

Manipulated Electrochemical Surface Reactions Induced By Oscillatory Electric Potentials On Metal Based Electrodes, Thomas Stone Welles

Dissertations - ALL

This research effort investigates the manipulation of surface electrochemical reactions induced by oscillating electric potentials on the surface of metal-based electrodes. Specifically, this research presents experimental data identifying modified electrochemical surface reactions caused by low magnitude electric potential oscillations on multilayered catalytic membranes and on implanted biometallic alloys. The scope of this effort consists of four major components: (1) perform an exhaustive literature review and analysis of the current understanding in applied surface electrochemistry and develop potential theoretical frameworks by which to interpret the experimental results; (2) identify the electrochemical manipulation via electrical oscillation while reacting nitric oxide on a …

Mutual Coupling Reduction Techniques For Multi-Band Base Station Antennas, Evan Christopher Wayton

Dissertations - ALL

This dissertation proposes antenna design techniques which suppress mutual coupling in densely populated dual-polarized broadband multi-band base station antenna (BSA) arrays for improved radiation characteristics. Array face densification without the proposed techniques leads to undesirable interactions between arrays and radome cover. This research is supported by extensive full-wave electromagnetic simulations, characteristic mode analysis, equivalent circuit models, and array theory. The results are validated through measurements of the radiation patterns and scattering parameters of fabricated prototypes.Upon excitation of a mid-band (MB) array, an electrically long low-band (LB) parasitic, necessary for broadband matching of the baseline LB dipole, exhibits dipole-like induced currents …

Thermal Management Using Liquid-Vapor Phase Change In Nanochannels, Sajag Poudel

Dissertations - ALL

Superior wettability of porous medium marks their potential to be used in the field of thermal management employing phase-change heat transfer. Comprehending the phenomena of wicking and liquid-vapor phase-change in micro/nano structured surfaces are key aspects towards advancing heat transfer solutions. In this work, fundamental understanding of droplet wicking, thin-film evaporation, and their subsequent application of heat-flux removal for cooling technology is first reported. The latter part of the dissertation is related to the disjoining pressure driven flow of nanoscale liquid film and liquid-vapor phase change in nano confinement. First, experimental and numerical investigation of droplet wicking in ∼728 nm …

Understanding And Hardening Blockchain Network Security Against Denial Of Service Attacks, Kai Li

Dissertations - ALL

This thesis aims to examine the security of a blockchain's communication network. A blockchain relies on a communication network to deliver transactions. Understanding and hardening the security of the communication network against Denial-of-Service (DoS) attacks are thus critical to the well-being of blockchain participants. Existing research has examined blockchain system security in various system components, including mining incentives, consensus protocols, and applications such as smart contracts. However, the security of a blockchain's communication network remains understudied.

In practice, a blockchain's communication network typically consists of three services: RPC service, P2P network, and mempool. This thesis examines each service's designs and …

Investigation Of Elastic Parameters And Pavement Modeling With Eps Geofoam, Engda Kassahun Temesgen

Dissertations - ALL

Models using EPS geofoam rely on input elastic parameters derived from compression tests on small size samples. Young's modulus and Poisson's ratio are parameters required to model isotropic and homogenous material behavior. For the most widely used EPS density grade of 20 Kg/m3 (1.25 pcf), Young's modulus of 4 MPa and Poisson's ratio of 0.1 are commonly used. Use of these values in models led to unreasonable long term deformation predictions that contradicted with field observations. Tests on small samples are prone to edge effects. Edge effects in turn result in underestimation of input elastic parameters. Alternative tests and sensing …

Atomistic Investigation Of Nucleosomal H3 Histone Tail In Unmodified And Epigenetically Modified States, Kathryn Piston

Dissertations - ALL

Epigenetics is a growing area of research that could potentially unlock the understanding of questions like how and why we develop certain diseases, how we age, how we inherit certain traits and even how our species evolves. Epi is a prefix meaning above, referring to chemical tags that sit above your genetics and dictate gene expression. Although there are many known links between certain epigenetic tags and diseases like cancer, the molecular mechanisms behind these links remains elusive. Gaining a novel understanding of the behavior of key biological targets for cancer like the histone H3 tail motivated this work. Histone …

Aging Study Of Silver-Exchanged Mordenite And Silver-Functionalized Silica Aerogel In Dry Air, Humid Air, No And No2, Seungrag Choi

Dissertations - ALL

Iodine-129 (129I) is one of the volatile radioactive species in the off-gas streams generated from the spent nuclear fuel reprocessing system, and it is essential to remove 129I vapor because 129I has a long half-life (1.6 x 107 years) and can be fatal to the human body if released to the environment. Radioactive iodine vapor can be effectively captured by silver containing adsorbents such as silver exchanged mordenite (Ag0Z) and silver functionalized silica aerogel (Ag0-aerogel) used in this study. However, the aging impact of off-gas streams on the adsorbents is one of major issues in the removal of radioactive iodine …

Analysis Of Multiple Degree-Of-Freedom Oscillatory Aquatic Propulsion, Seth Alan Brooks

Dissertations - ALL

Propulsive performance and flow field data were experimentally measured for a two degree-of-freedom fish platform. The fish platform was designed and constructed based on the yellowfin tuna (\textit{Thunnus albacares}) that is known to be both fast and efficient. This work extends the current understanding of oscillatory aquatic propulsion to a three-dimensional fish platform with full volume flow field data and propulsive performance. A parametric sweep of trailing-edge amplitude of the caudal fin ($A$), heave-to-pitch ratio ($h^*$), and phase offset between the two degrees-of-freedom ($\phi$) was used to explore a parameter space that encompasses and extends beyond the known biological domain. …

Algorithm Hardware Codesign For High Performance Neuromorphic Computing, Haowen Fang

Dissertations - ALL

Driven by the massive application of Internet of Things (IoT), embedded system and Cyber Physical System (CPS) etc., there is an increasing demand to apply machine intelligence on these power limited scenarios. Though deep learning has achieved impressive performance on various realistic and practical tasks such as anomaly detection, pattern recognition, machine vision etc., the ever-increasing computational complexity and model size of Deep Neural Networks (DNN) make it challenging to deploy them onto aforementioned scenarios where computation, memory and energy resource are all limited. Early studies show that biological systems' energy efficiency can be orders of magnitude higher than that …

Exploiting Building Demand Flexibility Through Machine Learning For Building-To-Grid Integration, Hannah Charlene Fontenot

Dissertations - ALL

Demand flexibility – the ability to adjust a building's load profile across different timescales – is a key aspect of the ongoing effort to increase interconnectivity between buildings and the power grid. By harnessing their demand flexibility, buildings can provide significant benefits to the grid and bolster grid resilience and reliability. To facilitate the transition toward the "smart grid", new and intelligent control approaches are required that can seamlessly integrate building, occupant, and grid data and effectively control multiple building assets to provide grid services while maintaining occupants' required thermal comfort levels and reducing the building's overall energy consumption and …