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Soil Moisture Dependent Runoff In A Dryland Region: An Investigation Of The Role Of Antecedent Conditions, Monitoring, And Modeling Strategies, Gerhard Schoener

Civil Engineering ETDs

Approximately 30% of the Earth’s land surface is characterized as arid or semiarid, including much of the western United States. Accurate runoff predictions are important for informed watershed management, particularly in rapidly urbanizing areas. Infiltration excess overland flow is the dominant mechanism for runoff generation in many dryland basins, and event-based infiltration or loss models are commonly used to estimate runoff. However, predictions are associated with considerable uncertainty due to the role antecedent soil moisture, an initial condition that must be set by the modeler. The objectives of my research were to (1) evaluate the impact of antecedent soil moisture …

The Effect Of Ph On Organic Carbon Uptake And Biological Phosphorus Removal By Tetrasphaera Polyphosphate Accumulating Organisms, Derek Belka

Civil Engineering ETDs

Tetrasphaera polyphosphate accumulating organisms (PAOs) have been found in greater abundance and may remove more P in full-scale enhanced biological phosphorus removal (EBPR) water resource recovery facilities (WRRF) worldwide than the more extensively studied Accumulibacter PAO. Understanding the effect that environmental conditions, such as pH, have on Tetrasphaera metabolisms is critical to understanding EBPR WRRF process upsets, achieving consistent low effluent P concentrations, and formulating optimization strategies. The objective of this study was to determine pH effects over the range from 5.5 to 8.5 on anaerobic amino acid uptake, P release, and cation release in a Tetrasphaera-enriched culture from …

Characterization Of Phase Behavior In Idp Solutions By Uv-Vis Spectrophotometry And Phase Volume Fraction Measurements In Capillaries, Qing Sun

Biomedical Engineering ETDs

Intrinsically disordered proteins (IDPs) play vital roles in cell signaling and regulation by changing conformation dynamically under various stimulus. Thus, it is crucial to understand their physical properties in vitro especially liquid-liquid phase separation (LLPS). Here, we first used UV-vis spectrophotometry to investigate two of IDPs' physical properties – transition temperature (Tt) and coacervate size. This deeper insight allows us to further understand the dynamics of phase growth. We then constructed a binodal curve in the phase diagram by measurement of volume ratios in phase separated IDP solution in glass capillaries.

Systems And Methods For Scalable Retinal Screening Programs, Jeremy Richard Benson

Computer Science ETDs

This dissertation addresses gaps in artificial intelligence-based computer vision tasks in the medical image processing field. We demonstrate effective methods for standardizing and augmenting digital fundus photographs so that robust convolutional neural network-based systems can perform high-throughput disease classification and generalize to never-before-seen data from novel camera technologies, scaling with the changing hardware landscape, as well as keeping up with vast amount of incoming data from the ever-increasing population. We also tackle the problem of discovering relevant samples in an unlabeled cohort of image data, thus widening the bottleneck to all downstream supervised machine learning tasks.

Intracavity Phase Interferometry Based Fiber Sensors, Luke Jameson Horstman

Optical Science and Engineering ETDs

Intracavity Phase Interferometry (IPI) is a detection technique that exploits the inherent sensitivity of a laser's frequency to the parameters of its cavity. Intracavity interferometry is orders of magnitude more sensitive than its extracavity alternatives. This dissertation improves on previous free-space proof-of-concept designs. By implementing the technique in fiber optics, using optical parametric oscillation, and investigating non-Hermitian quantum mechanics and dispersion tailoring enhancement techniques, IPI has become more applicable and sensitive. Ring and linear IPI configurations were realized in this work, both operating as bidirectional fiber optical parametric oscillators. The benefit of using externally pumped synchronous optical parametric oscillation is …

Synthetic Aperture Optical Imaging Interferometric Microscopy With Improved Image Quality, Preyom K. Dey

Electrical and Computer Engineering ETDs

The resolution limit of optical microscopy can be extended by using Imaging Interferometric Microscopy (IIM), which uses a low numerical aperture (NA) objective lens to achieve resolution equivalent to that of a high-NA objective lens with multiple sub-images. Along with the resolution enhancement challenge, IIM often suffers from poor image quality. In this dissertation, several image quality improvement methods are proposed and verified with simulation and experimental results. Next, techniques to extend the resolution limit of IIM to ≤ 100nm using a low-NA objective lens are demonstrated. An experimental technique of using a grating coupler on …

Ultrafast Spectroscopy Of Air Lasing In Filaments, Brian Robert Kamer

Optical Science and Engineering ETDs

Filamentation in air is a phenomenon that has been extensively investigated for the last two decades. At sufficiently high intensity, even air is a nonlinear medium. These intensities are reached with ultrashort pulses (50 to 100 fs) of more than 1 J energy, which self-focus in air, reach ionizing intensities of oxygen and nitrogen, creating a plasma that defocuses the beam. The air filament is a self-induced waveguide resulting from a balance of focusing and defocusing. In this work new techniques were developed to visualize and analyze this phenomenon through its emission, in particu- lar the UV emission of the …

Reconfigurable Antennas & Matching Networks For Cubesats, Marios Patriotis

Electrical and Computer Engineering ETDs

Telecommunication has rapidly evolved in the past decades, quickly becoming one of the most expansive industries, especially with the presence of new attractive eras like 5Gnetworks, automotive radars, and CubeSats. The use of miniaturized satellites such as CubeSats for cheaper and wider communication coverage has opened the possibilities for cluster satellite communication. These units exist in a continuously varying environment as much physical as electromagnetic. Hence, the establishment of a successful communication link among the space units but also ground stations becomes challenging. This new situation can be confronted with the installation of new reconfigurable antennas. These are emitting units …

An Investigation Of Phosphorus Removal By Purple Bacteria In Dairy Wastewater Lagoons, Lauren M. Gomez, Andrew J. Schuler, Jose M. Cerrto, David T. Hanson

Civil Engineering ETDs

The objective of this study was to determine whether the polyphosphate metabolism in purple photosynthetic bacteria (PPB) is similar to that of wastewater polyphosphate-accumulating organisms (PAOs) such as Accumulibacter. Dairy lagoon samples were studied in continuous and batch laboratory tests to evaluate whether cyclic light and dark conditions for PPB are similar to aerobic and anaerobic conditions for PAOs in domestic wastewater treatment systems. 16s rRNA gene amplicon sequencing indicated the presence of the purple sulfur bacterium Thiolamprovum (53.92%) in one lagoon source, and Thiodictyon (3.50%) in a second lagoon. Phosphorus contents were at least 0.7% higher than the …

Interferometric Lithography- An Approach To Large Area And Cost Effective Nanopatterning, Vineeth Sasidharan

Optical Science and Engineering ETDs

In this dissertation interferometric lithography is approached in two different ways to address two important constraints of nanopatterning. One approach solves the problem of scaling up interferometric lithography to wafer scale (4 inch or larger) area. Through the second approach we have developed a nanopatterning technique based on interferometric lithography by using an inexpensive (~$100) diode laser as source, making interferometric lithography a very cost-effective technique.

Wafer-scale large-area nanopatterning was developed using an amplitude grating mask as a grating beam splitter along with spatial averaging of laser intensity by wobbling. The longitudinal and transverse coherence issues both are eased by …

The Profound Photophysical Effects Of Organic Chromophore Connectivity And Coupling, David J. Walwark Jr

Nanoscience and Microsystems ETDs

Through-bond and through-space interactions between chromophores are shown to have wide-ranging effects on photophysical outcomes upon light absorption in organic molecules. In collapsed poly(3-hexylthiophene), through-space coupling creates hybrid chromophores that act as energy sinks for nearby excitons and favorable sites for molecular oxygen to dock. Upon excitation with visible light the highly-coupled chromophores react with the docked oxygen and subsequently do not quench nearby excitons as efficiently. In tetramer arrays of perylene diimide chromophores the central moiety through-bond connectivity is synthesized in two variants which exhibit vastly different single-molecule blinking behavior and theoretically-predicted electronic transition character. In the more-connected tetramer …

Three-Dimensional Lattices As Effective Impact Absorption Layers For Space Applications, James Youchison

Mechanical Engineering ETDs

Additive manufacturing (AM) is increasingly becoming a viable manufacturing process due to dramatic advantages that it facilitates in the material selection and design complexity. This paper investigates the potential of additively manufactured lattice structures for the application of dissipating impact energy. In this research the role of geometry and material properties on the static and dynamic energy absorption properties of additively manufactured wave spring lattices composed of various materials were studied under drop/impact and compression tests. A finite element simulation of the lattice structure was also conducted, although the results were overall inconclusive, it gave some great insight into the …

Cognizant Composites: Seamless Integration Of Circuitry And Sensors Into Structural Composites, Reuben Fresquez

Computer Science ETDs

This thesis describes a set of novel techniques for embedding sensors, circuitry, and electronics into structural composites. I leverage recent developments in human computer interaction to create sensors and circuitry that are seamlessly incorporated into structural composites. I fabricate bend and compression sensors, along with circuitry, from textiles, which enables me to add electronic capabilities without impacting the composite’s structural integrity. I describe the construction of these “cognizant composites” and demonstrate their functionality. I also explore techniques for embedding standard electronic components, including microcontrollers, into structural composites. Potential applications of this technology include buildings that can warn occupants if load-bearing …

Silica Sol-Gel Control With High Voltage Contactless Electrodes, Jonathan C. Hebert

Nanoscience and Microsystems ETDs

High Voltage Contactless Electrodes (HVE) non-evasively modulates silica sol-gel reactions by redistributing charge in solution. HVE induces formation of local neutral band (LNB) strata (pseudo interfacial surfaces) where the gradient of potential is zero ∇𝜓𝜓=0. HVE LNB shape corresponds to solubility and ultimately sol-gel form. HVE silica sol-gel control works by localizing pH and creating conditions where silanol polymerization is biform; condensation by protonation (cathodic), or by deprotonation (anodic). Steric modified Poisson-Boltzmann equation is used to develop a theory on HVE control of silica sol-gel formation and a nucleate potential functional of potential 𝜓𝜓. Technologies developed during this research are …

Monte Carlo Perturbation Analysis Of Dimension And Density Variations Of The Annular Core Research Reactor Model Fuel, Karissa Currie

Nuclear Engineering ETDs

This thesis assesses sources of uncertainty in the neutron energy spectrum of the Annular Core Research Reactor (ACRR) Monte Carlo N-Particle Transport Code (MCNP) model. Uncertainty evaluations have been performed on the ACRR core but were computationally intensive and could not isolate the uncertainties associated with discrete sources. Monte Carlo Perturbation Theory (MCPT) is used in MCNP to calculate 640-group neutron energy fluences and their associated uncertainties [1]. To understand the uncertainties associated with only the UO₂-BeO fuel, perturbations in densities and dimensions were evaluated. A 640 by 640 covariance and correlation matrices were produced and compared to …

Measurement Of Resilience Performance For Infrastructure Construction Project Delivery, Fei Han

Civil Engineering ETDs

In the past decade, infrastructure resilience in the U.S. has become critical due to increasing disruptions to the built environment and the resultant consequences on economic, social, and environmental goals. This attention to resilience research is drawn to investigating the ability of existing structures and facilities to resist and recover from natural and human-caused hazards. From a broader view, resilience also applies to processes, such as infrastructure project delivery processes. During these processes, a project often suffers inevitable threats and disruptions, which can significantly delay or derail the project if the process is not resilient.

This research aimed to conceptualize …

Explorations And Developments In Multifunctionality, 3d Printing, And Accelerated Aging For Thermoplastics And Thermosets, Zachary Brounstein

Nanoscience and Microsystems ETDs

If the world is to progress through the fourth industrial revolution, rapid advances in materials science must complement new technological feats in manufacturing, computation and device functionality, and a broader understanding of how materials behave as they age and degrade. To this effect, much effort has been directed towards polymeric materials to address and solve many problems in this new era. This includes developing polymer composites that incorporate fillers to imbue multifunctionality, fabricating novel formulations for additive manufacturing, and conducting aging studies to assess the performance of these materials over long time spans. Building and expanding on the latest research …

Fabrication Of Oxide-Based Memristors For Neural Networks, Jamison E. Wagner

Electrical and Computer Engineering ETDs

This thesis discusses what a memristor is, how it is hypothesized to work and the fabrication work undertaken with hafnia and titania-based ultrathin oxide films. In addition, the electrical tests utilized to characterize the physical performance of the memristors including but not limited to, their IV hysteresis responses, yield rates and overall reliability. The results and discussion of this work are aimed at better understanding how fabrication of memristive devices can be further improved for future work.

Intelligent Internet Of Things Frameworks For Smart City Safety, Dimitrios Sikeridis

Electrical and Computer Engineering ETDs

The emerging Smart City ecosystem consists of a vast edge network of Internet of Things (IoT) devices that continuously interact with mobile devices carried by its citizens. In this setting, the IoT infrastructure, apart from the main communications facilitator, acts as a crowdsourcing mechanism that collects massive amounts of user data, and can support public safety applications for the Smart City. In this thesis, we design and analyze learning mechanisms that extract intelligence from crowd interactions with the wireless IoT infrastructure, and optimize its energy efficiency while operating as a public safety network. First, we deploy a multi-story facility testbed …

Investigating Operational Modes In Gallium Nitride Photoconductive Switches, Brad J. Maynard

Electrical and Computer Engineering ETDs

As switching requirements for speed, power, and efficiency become more stringent, advances in wide-bandgap (WBG) materials has enabled their use in high power switching devices. One such device, the photoconductive semiconductor switch (PCSS), while previously constructed from GaAs, shows promise using WBG Mn-doped GaN. Lateral and vertical geometries of PCSS have been produced and evaluated for operation using sub-mJ/ns regime pulsed laser incidence. At fields below 25 kV/cm, the lateral switch operates in the linear regime where modest photocurrent fitting the laser envelope is observed. Above this threshold, the switches demonstrate circuit-limited persistent conductivity (PC) current, in what is presumed …

Fast Video-Based Face Recognition In Collaborative Learning Environments, Phuong Tran

Electrical and Computer Engineering ETDs

Face recognition is a classical problem in Computer Vision that has experienced significant progress recently. Yet, face recognition in videos remains challenging. In digital videos, face recognition is complicated by occlusion, pose and lighting variations, and persons entering and leaving the scene. The goal of the thesis is to develop a fast method for face recognition in digital videos that is applicable to large datasets. Instead of the standard video-based methods that are tested on short videos, the goal of the approach is to be applicable to long educational videos of several minutes to hours, with the ultimate goal of …

Smart Energy Harvesting For Internet Of Things Networks, Fisayo Sangoleye

Electrical and Computer Engineering ETDs

In this thesis, we address the problem of prolonging the battery life of Internet of Things (IoT) nodes by introducing a smart energy harvesting framework for IoT networks supported by femtocell access points (FAPs) based on the principles of Contract Theory and Reinforcement Learning. Initially, the IoT nodes’ social and physical characteristics are identified and captured through the concept of IoT node types. Then, Contract Theory is adopted to capture the interactions among the FAPs, who provide personalized rewards, i.e., charging power, to the IoT nodes to incentivize them to invest their effort, i.e., transmission power, to report their data …

Contract-Theoretic Demand Response Management In Smart Grid Systems, Nafis Irtija

Electrical and Computer Engineering ETDs

The sheer growth of electricity demand and the rising number of electricity-hungry devices have highlighted and elevated the need of addressing the demand response management problem in residential smart grid systems. In this thesis, a novel contract-theoretic demand response management (DRM) framework in residential smart grid systems is introduced based on the principles of labor economics. The residential households produce and consume electricity, acting as dynamic prosumers. Initially, the prosumers' personal electricity generation and consumption characteristics are captured by introducing the concept of prosumers' types. Then, the prosumers' and the electricity market's profit is depicted in representative utility functions. Based …

The Physics Of Slot-Die And Gravure Coating Associated With Precision Thin Films And Coating Defects, Robert E. Malakhov

Nanoscience and Microsystems ETDs

Enabling future printable and flexible electronic (PFE) devices and technologies requires overcoming the technical challenge of manufacturing precision thin films and features at scale. Coating- and print-feature functionality for PFEs is imparted with dispersed active particulate inks that provide electronic properties via slot-die coating, a pre-metered film-deposition process, and gravure printing, a high-throughput, precision process. Both are poised to be ideal manufacturing technologies for PFEs but require further research to understand particulate effects in defect formation and processability. Therefore, overcoming the technical challenges of precision, throughput, and the complexities of particulate inks is the purpose of this work. For slot-die …

3d Printed Concrete & Polymer Concrete For Infrastructure Applications, Daniel Heras Murcia

Civil Engineering ETDs

Additive manufacturing technology has been established as one of the fastest-growing building technologies worldwide. Three-dimensional concrete printing (3DCP) has developed an increasing interest in the last decade due to its prospects as a transformative technology for industries such as the concrete precast. Besides the improvements in automation technologies in construction, traditional construction has faced considerable challenges: high accident rates, labor dependency, significant potential for automation, and high costs associated with the use of traditional formwork. In this context, three-dimensional concrete, also referred to as physical prototyping, is a novel construction technique in which the concrete is extruded layer-to-layer. 3DCP is …

Towards Creating Smart Cities In Nepal, Ambika P. Adhikari, Keshav Bhattarai

Himalayan Research Papers Archive

Many urban centers in the world are seeking to become smart cities. Nepali city leaders are also aspiring to make their cities smart. A smart city basically has clever improvements made in three sectors of its operations: technological, human, and institutional. Globally, many cities have recently made impressive enhancements in at least one or more of these areas. Nepal’s National Planning Commission (NPC) in 2016 had released a concept paper on smart cities for Nepal, defining smart cities as sustainable, information and technology-based, with high quality services and replicable (NPC 2016). As most Nepali cities still operate with limited infrastructure, …

Pseudo-Ductile 3d Printed Fiber Reinforced Polymer Composites, Shreya Vemuganti

Civil Engineering ETDs

The use of fiber-reinforced polymer (FRP) composite materials is continuously growing in civil infrastructure owing to its high strength, low weight, and manufacturing flexibility. However, FRP is characterized by sudden failure and lacks ductility. When used in construction, gradual failure of FRP components is desired to avoid catastrophic structural collapse. Due to its mechanical orthotropy, the behavior of FRP relies significantly on fiber orientation and stacking sequence. In this research proposal, investigations showed that novel multi-angled glass fiber reinforced polymer (GFRP) composites with varying fiber orientation angles, stacking sequence, and thickness of laminas can be designed and fabricated using 3D …

Machine Learning Based Dynamic Power Dispatching And Smoothing Using Hybrid Energy Storage System For Renewable Energy Systems, Bhuvaneshwarr Ramalingam

Electrical and Computer Engineering ETDs

The stochastic fluctuations from Renewable Energy Resources (RER) have a great influence on power quality and off-grid communities. A combination of the different storage systems is accessible for RER generation intermittency and to bring about finest smoothing operating cycle compared to sole Energy Storage System (ESS). Additionally, energy management in Hybrid Energy Storage System (HESS) creates an uncertainty during power smoothing operation. This research materializes, an intelligent mechanism for power smoothing and dispatch with the introduction of hybridized storage that can accommodate the unpredictable behavior of RER under dynamic load. A feed-forward neural network is proposed as a power smoothing …

Converting Parylene C Into A Thin Film Piezoelectric Material, Murali Manohar Duggina

Nanoscience and Microsystems ETDs

Thin-film piezoelectric materials are increasing in demand, but most materials are stiff ceramic materials. Polyvinylidene fluoride (PVDF) is a common polymer piezoelectric material, but it has limitations such as it requires post-processing steps to promote appropriate β-phase and it has a low operating and Curie Temperature, which limits its use in traditional microfabrication processing. The toxicity of PZT makes it incompatible with biomedical applications. Therefore, there is a need to develop a new class of polymer piezoelectric films that are compatible with current microfabrication methods. Parylene C (PA-C) is a chemical vapor deposited semi-crystalline polymer material with a nonsymmetric polymer …

Interaction Of A Shock Wave With A Particle Curtain, Daniel M. Freelong

Mechanical Engineering ETDs

This thesis presents an experimental study of the interaction of a normal shock wave with a sparse curtain of particles. Soda lime particles with a nominal diameter of 40 micrometers are used to form the curtain. A high speed camera captured several segments of the particle curtain flow from the front view, including the early formation stages. The frames from the video segments were then extracted into individual sequential images. Properties were found using the images such as the velocity fields, time evolution of multiphase Atwood number, and perturbation growth. Volume fractions were derived from mass discharge measurements and particle …