Engineering Commons^™

Development Of Protocols For Determining Deleterious Material Content In Crushed Recycled Glass, Fiona Nutbeam

Graduate College Dissertations and Theses

Glass recycling appears to be a viable way to reduce waste; however, there are many challenges to ensuring the recycled product has an economically and environmentally sustainable end use. Cleaning recycled glass to a standard that allows it to be melted down into new glass is extremely difficult when single-stream recycling is in practice. The recycled glass that is not melted down is processed into different materials, such as processed glass aggregate (PGA). As states implement bans on landfilling recyclable materials (e.g., Act 148 in Vermont), additional uses for PGA are needed. In New England, there are diminishing sources of …

On The Enhancement Of Penetrating Radar Target Location Accuracy With Visual-Inertial Slam, Joshua Girard

Graduate College Dissertations and Theses

This paper presents research concerning the use of visual-inertial Simultaneous Localization And Mapping (SLAM) algorithms to aid in Continuous Wave (CW) radar target mapping. SLAM is an established field in which radarhas been used to internally contribute to the localization algorithms. Instead, the application in this case is to use SLAM outputs to localize radar data and construct three-dimensional target maps which can be viewed in augmented reality. These methods are transferable to other types of radar units and sensors, but this paper presents the research showing how the methods can be applied to calculate depth efficiently with CW radar …

Strain-Enhanced Coherent Exciton-Polaron States In 1d Phthalocyanine Crystalline Thin Films, Libin Liang

Graduate College Dissertations and Theses

Organic semiconductors are at the forefront of materials research, due to their desired electric and mechanical properties. They offer the unique opportunity to modify material properties during synthesis process, opening an avenue to the development of novel flexible and wearable electronic and photonic devices.Molecular excitons are of importance in organic semiconductor properties. While majority of research studies are centered on achieving good control of amorphous or polycrystalline thin film properties, the static disorder effect leads to poor device performance when compared to inorganic semiconductors with superior crystalline ordering. On the other hand, the macroscopic molecular long-range ordering can enhance device …

Tuning Electroluminescence From Resonators Based On Fabry-Pérot Microcavity Oleds, Ekraj Dahal

Graduate College Dissertations and Theses

This thesis comprises a series of methods for controlling the electroluminescence from Fabry-Pérot microcavity OLEDs by varying the resonator geometry and the location of the organic emitter within the resonator. In pursuit of this thesis, I conducted three experimental projects backed by theoretical modeling. First the thickness of the microcavity was varied to observe changes in resonant state wavelength, linewidth of the states, angular dispersion, and polarization splitting. The resulting electroluminescence can be tuned to span the entire color gamut using a single green chromophore. Electroluminescence of this green chromophore was used to pump the optical states of nominally identical …

Characterization Of Effects Of Electric And Acoustic Fields On Fouling During Microfiltration Experiments, Yuxiang Shen

Graduate College Dissertations and Theses

Membrane processes have been a promising purification and separation technique as it can potentially remove any ions, particles, and colloids by size selection. Membrane processes are still limitedly used in the real-world industrial application due to its relatively cost prohibitive maintenance and operation, which is attributed to membrane fouling and concentration polarization under pressurized conditions. To improve the efficiency of membrane filtration, alternatives to the traditional cleaning methods have been investigated to mitigate the fouling and concentration polarization problems. Among the alternatives, application of an external field, e.g., electric field or acoustic field, to the mitigate fouling during membrane filtration …

Chitosan-Based Shrinking Fibers For Post-Cure Stressing To Increase Durability Of Concrete, Diarmuid Gregory

Graduate College Dissertations and Theses

Concrete is a ubiquitous building material with an extensive history, yet it has a fair number of imperfections. Its sizeable environmental impact, low tensile to com- pressive strength ratio, and lack of durability leave room for innovation. Concrete durability frames the motivation for this research.This thesis presents the motivation, methods, and findings of tests performed to quantify the durability of concrete reinforced with automatically shrinking chitosan- based fibers. A literature review, the procedures for synthesizing chitosan fibers, and preliminary tests of the control fibers are all discussed. Two different types of durability tests were carried out: rapid freezing and thawing …

Finite Element Deformation Of Silver Nanowire Networks, Akiva Gopalkrishnan

Graduate College Dissertations and Theses

Tin doped Indium oxide currently is the dominant material used in the field of transparent electronics (TE) but suffers from Indium scarcity and brittle failure under small deformations. Silver Nanowires (AgNWs) are of considerable research interest due to their relative ease of fabrication, high conductivity, and mechanical ductility, as well as high corrosion stability. Existing research on single AgNWs via nanomechanical testing has shown an increase in the strength and ductility as both the diameter and gauge length is reduced, or a “smaller is stronger effect”. The formation of a network structure of AgNWs on flexible plastic substrates is essential …

Constraint-Aware And Efficiency-Aware Control Of Air-Path In Fuel Cell Vehicles, Eli Bacher-Chong

Graduate College Dissertations and Theses

Fuel cell technology offers the potential for clean, efficient, robust energy productionfor both stationary and mobile applications. But without fast and robust control systems, fuel cells cannot hope to maintain real-life efficiencies near enough to their theoretical potential. This work studies control and constraint management techniques to regulate a nonlinear multivariable air-path system for a proton exchange membrane fuel cell (PEMFC). The control objectives are to avoid oxygen starvation, run at the maximum net efficiency, achieve fast tracking of air flow and pressure set-points, and be easy to calibrate. To operate at maximum efficiency, a set-point map is generated for …

Atomic-Scale Analysis Of Solute Segregation Energy Into Grain Boundaries And Polycrystals, Tara Nenninger

Graduate College Dissertations and Theses

Solute segregation in grain boundaries (GBs) is used in design to stabilize nanocrystalline alloys. While analyzing GB segregation energy as a spectrum allows for a more in-depth analysis of the effects of GB atomic structure on solute segregation, this method inherently ignores solute-solute interaction by nature of considering one solute at a time. Here we develop an efficient molecular statics (MS) algorithm for determining the local effect of solute-solute interaction on GB segregation. We apply this algorithm to a Σ9 (221) symmetric tilt grain boundary in a bicrystal as well as a randomly oriented polycrystal for Ni and Cu solutes …

Emergence Of Elasto-Inertial Turbulence In 2d Natural Convection Flow With Polymer Additives, Fuqian Yin

Graduate College Dissertations and Theses

Elasto-Inertial Turbulence (EIT) is a recently discovered state of chaos triggered by the addition of polymers in a liquid flow. Its presence in wall-bounded parallel flows, pipe and channel flows, has been well-established. The present research investigates the existence of EIT in large circulations, specifically the Rayleigh-B\'{e}nard cells (RBC) caused by natural convection between two horizontal plates with a negative temperature gradient. The method of investigation is high-fidelity two dimensional direct numerical simulation of the constitutive polymer model FENE-P. The flow parameter space is mostly subcritical, characterized by $Ra$, Rayleigh number, below or equal to $10^6$, which loosely defines the …

Travel Behavior, Responses To Fuel Prices, And Barriers To Change In Small And Rural Communities, Erica Quallen

Graduate College Dissertations and Theses

Travel behavior and the factors which drive it in small and rural communities has been historically understudied in transportation research. By understanding these factors and behaviors, a clearer picture of these regions can be drawn so that meaningful change towards greenhouse gas reductions can be realized. My research aims to examine barriers to making sustainable travel behavior changes such as using multi-modal transportation, reducing overall amounts of travel, or moving to locations closer to necessary services. I do this by first evaluating what “rural” means in terms of existing definitions of the term. The assessment of rural definitions analyzes vehicle …

A Holistic Approach To River Restoration Design And Conservation Planning On The Reach And Basin Scales Using Hydraulic Modeling And Multi-Objective Optimization Tools, Lindsay Courtney Worley

Graduate College Dissertations and Theses

Flooding events around the world cost billions (USD) in damages each year. For decades, engineers have combated flood related damages by implementing flood mitigation controls such as channelization, levees or berms, and armoring. Recent advances in the study of river dynamics, however, have challenged the efficacy of these traditional flood mitigation techniques and pose that these structures are disconnecting channels from their floodplains, increasing flow rates, and contributing to more erosion. The effects of climate change combined with future predictions of increased storm frequency and intensity make it necessary to revise flood hazard mitigation strategies. A more nature-based alternative to …

The Optimization Of Rifle Barrel Harmonics, Daniel O'Neil

Graduate College Dissertations and Theses

From the optimization of mechanical systems perspective, firearms offer a plethora of complex scenarios. Many variables, coupled with sometimes unstable systems, must be balanced appro- priately by the user to achieve precision, that is to say, to hit the target bullseye from some distance away with a small projectile launched on a parabolic trajectory. The sources of error entirely affect final terminal precision, some of them related to human factors, others related to the quality of the ammunition, and the remaining associated with the mechanical capability of the weapon. This thesis documents the vibrations analysis of an isolated rifle barrel, …

Pymoocfd - A Multi-Objective Optimization Framework For Cfd, George Martin Cunningham Love

Graduate College Dissertations and Theses

Modern computational resource have solidified the use of computer modeling as an integral part of the engineering design process. This is particularly impressive when it comes to high-dimensional models such as computational fluid dynamics (CFD) models. CFD models are now capable of producing results with a level of confidence that would previously have required physical experimentation. Simultaneously, the development of machine learning techniques and algorithms has increased exponentially in recent years. This acceleration is also due to the widespread availability of modern computational resources. Thus far, the cross-over between these fields has been mostly focused on computer models with low …

Application Of Nanoparticles In Photodynamic Therapy And Increased Endothelial Permeability By Nanoparticle-Induced Activation Of Trpv4: Towards Improved Understanding Of Nanomedicine, Jaspreet Singh Nagi

Graduate College Dissertations and Theses

Nanotechnology holds great promise in biomedicine towards new diagnostics, new therapies, and improved patient outcomes. This work explores both the application of a novel nanoparticle in an established field of cancer treatment as well as an investigation of the human health implications of nanoparticles in intravenous applications. First, novel dye-linked zinc oxide nanoparticles (NPs) were investigated for use as photosensitizers (PS) for photodynamic therapy (PDT) due to their excellent thermal- and photo-stability. To overcome the limitations of current cancer treatments, we investigated the effectiveness of ZnO-Dye 847 NPs as a near infrared (NIR) PS in PDT. The NPs were surface …

Open-Source Wearable Sensors For Detecting Fall Risk In Patients With Multiple Sclerosis, Conor Joyce

Graduate College Dissertations and Theses

Wearable sensors are growing in popularity in the medical field to help measurephysiological signals from patients. The M-Sense Research Group at the University of Vermont uses wearable sensors to measure accelerometer and gyroscope data of patients with multiple sclerosis amongst other clinical applications. The sensors are attached directly to a patient’s skin on the chest and thigh and are worn for anywhere from an hour or two when being monitored in the lab or for five weeks when wearing the sensors at home. Current wearable sensors are closed source and do not allow recorded data to be seen in real …

Active Acoustic Sensing Technologies For Practical Uav-Based Condition Assessment Of Underside Bridge Decks, Damien Garland

Graduate College Dissertations and Theses

Reinforced concrete bridge decks are high performance structural elements that must survive decades of harsh mechanical and environmental loads. The structural health monitoring of bridges is a primary enabler of safe and cost-effective performance, relying on frequent inspections and repairs as needed. The undersides of concrete bridge decks are oft-overlooked areas of inspection, owing to a hard to reach and difficult location to access. Exacerbating factors to the degradation of concrete bridge decks are the freeze-thaw cycle and salt water related corrosion common in the world’s Northern climates. As concrete weathers, it decays. Corrosion induced cracking and delamination are primary …

Medical Applications Of Ultrasound: T-Cell Drug Delivery, Osteoporosis Diagnosis, And Biofilm Mitigation, Alina Karki

Graduate College Dissertations and Theses

The ability of ultrasound to localize acoustic energy deposition and induce a biological effect within a target is examined in three novel biomedical applications: sonoporation, osteoporosis diagnosis, and biofilm mitigation.Ultrasound can excite encapsulated microbubbles, causing an acoustic cavitation effect in the vicinity of cells, temporarily increasing membrane permeability, and allowing cells to uptake foreign molecules. This non-viral transfection technique is called sonoporation. Our experimental study demonstrated that it could be effective for small interfering RNA (siRNA) delivery into an isolated mouse and human T-cells, which is a complex process despite its importance in treating numerous diseases. T-cells are non-proliferating, while …

Exploring Mycorrhizae In Riparian Restoration To Enhance Phosphorus Mitigation And Pollinator Habitat On Unceded Territory, Jessica Ann Rubin

Graduate College Dissertations and Theses

When land degradation imperils freshwater quality, land managers can restore ecosystem functions. The premise of three published/accepted thesis chapters is that mycorrhizae can enhance water quality function of riparian buffers and pollinator habitat through diverse, native polyculture associations.

Where water quality is threatened through excess phosphorus (P) loads from agriculture, riparian buffers are considered Best Management Practices (BMPs). They intercept agricultural nutrients before reaching waterways. However, their seasonal cycles, saturation capacity, and often degraded conditions limit their ability to protect water quality. In particular, riparian buffers can transition from sinks to sources of P when agricultural practices chronically contribute P, …

Three Branch Diversity Systems For Multi-Hop Iot Networks, Sakil Ahmed Chowdhury

Graduate College Dissertations and Theses

Internet of Things (IoT) is an emerging technological paradigm connecting numerous smart objects for advanced applications ranging from home automation to industrial control to healthcare. The rapid development of wireless technologies and miniature embedded devices has enabled IoT systems for such applications, which have been deployed in a variety of environments. One of the factors limiting the performance of IoT devices is the multipath fading caused by reflectors and attenuators present in the environment where these devices are deployed. Leveraging polarization diversity is a well-known technique to mitigate the deep signal fades and depolarization effects caused by multipath. However, neither …

Resilience And Decarbonization Of Energy Systems: A Data Driven Approach, Molly Rose Kelly-Gorham

Graduate College Dissertations and Theses

Concerns about climate change are leading to a transformation of energy systems, including increased adoption of renewable and distributed power generation and energy storage. Climate change is also increasing uncertainties in the environmental conditions in which electric power systems operate and increasing regional vulnerability to extreme events. Under this variable and uncertain environment, there is a need for research that identifies high risk vulnerabilities and that identifies technology and policies that most effectively improve resilience. However, quantifying resilience is hard. No single number can fully describe the resilience of a particular system, and there is as of yet no consensus …

Reference Governors For Mimo Systems And Preview Control: Theory, Algorithms, And Practical Applications, Yudan Liu

Graduate College Dissertations and Theses

The Reference Governor (RG) is a methodology based on predictive control for constraint management of pre-stablized closed-loop systems. This problem is motivated by the fact that control systems are usually subject to physical restrictions, hardware protection, and safety and efficiency considerations. The goal of RG is to optimize the tracking performance while ensuring that the constraints are satisfied. Due to structural limitations of RG, however, these requirements are difficult to meet for Multi-Input Multi-Output (MIMO) systems or systems with preview information. Hence, in this dissertation, three extensions of RG for constraint management of these classes of systems are developed. The …