Digital Commons Network^™

Energy Dissipation In A Sand Damper Under Cyclic Loading, Ehab Sabi

Civil and Environmental Engineering Theses and Dissertations

Various seismic and wind engineering designs and retrofit strategies have been in development to meet structures' proper and safe operation during earthquake and wind excitation. One such method is the addition of fluid and particle dampers, such as sand dampers, in an effort to reduce excessive and dangerous displacements of structures. The present study implements the discrete element method (DEM) to assess the performance of a pressurized sand damper (PSD) and characterize the dissipated energy under cyclic loading. The idea of a PSD is to exploit the increase in shearing resistance of sand under external pressure and the associated ability …

Leveraging Crowdsourced Navigation Data In Roadway Pluvial Flash Flood Prediction, Arefeh Safaei-Moghadam

Civil and Environmental Engineering Theses and Dissertations

This dissertation develops and tests a new data-driven framework for short-term roadway pluvial flash flood (PFF) risk estimation at the scale of road segments using crowdsourced navigation data and a simplified physics-based PFF model. Pluvial flash flooding (PFF) is defined as localized floods caused by an overwhelmed natural or engineered drainage system. This study develops a data curation and computational framework for data collection, preprocessing, and modeling to estimate the risk of PFF at road-segment scales. A hybrid approach is also developed that couples a statistical model and a simplified physics-based simulation model in a machine learning (ML) model to …

Silicon Photonics Trench Coupler Design, Foundry Fabrication, And Characterization, Evan Stewart

Mechanical Engineering Research Theses and Dissertations

In this thesis, compact 2-by-2 and 4-by-4 trench couplers in the silicon photonics material system have been designed, fabricated, and tested. The couplers operate on the principle of frustrated total internal reflection, allowing a footprint significantly smaller than industry standard y-couplers. As photonic integration evolves, larger scales of integration will benefit from such reduction in component size. The couplers were manufactured at the AIM silicon photonics foundry using processes available to multi-project wafer runs. The characterization of the trench couplers involves novel use of U-turns to provide efficiency estimates. For this generation of trench coupler, the experimental loss is measured …

Experimental And Numerical Studies On Laser Hot Wire Cladding By A High-Power Direct Diode Laser, Mingpu Yao

Mechanical Engineering Research Theses and Dissertations

Laser hot wire cladding is an advanced surface modification technology. It has been extensively growing during the last decades due to its high deposition rate, good metallurgical bonding between the substrate and clad layer, low dilution ratio, and small heat-affected zone. There are many kinds of lasers widely used in the laser cladding process. The high-power direct diode laser is widely welcomed because of its high energy efficiency, high electro-optic conversion efficiency, low cost, and high reliability. A rectangular-shaped direct diode laser beam combined with hot wire feeding can achieve a lower dilution depth with a uniform fusion line compared …

Novel Locomotion Methods In Magnetic Actuation And Pipe Inspection, Adam Cox

Mechanical Engineering Research Theses and Dissertations

There is much room for improvement in tube network inspections of jet aircraft. Often, these inspections are incomplete and inconsistent. In this paper, we develop a Modular Robotic Inspection System (MoRIS) for jet aircraft tube networks and a corresponding kinematic model. MoRIS consists of a Base Station for user control and communication, and robotic Vertebrae for accessing and inspecting the network. The presented and tested design of MoRIS can travel up to 9 feet in a tube network. The Vertebrae can navigate in all orientations, including smooth vertical tubes. The design is optimized for nominal 1.5" outside diameter tubes. We …

Improved Computational Tools For Infrasound Analysis, Jordan W. Bishop

Geosciences

Infrasound describes low frequency (≤ 20 Hz) acoustic waves that can propagate long ranges (≥ 1000 km) through wave guides in the atmosphere. This characteristic makes infrasonic waves a useful monitoring technology for a variety of violent phenomena such as volcanic eruptions. However, source processes may be complex, and infrasound waves are continually modified as they interact with the ground and dynamic atmosphere along their propagation path. Additionally, infrasound still has a data quantity problem: vast amounts of raw data are now continuously generated from permanent arrays distributed around the world, but ground truth information, when possible, may be difficult …

Processes In The Percolation Zone In Southwest Greenland: Challenges In Modeling Surface Energy Balance And Melt, And The Role Of Topography In The Formation Of Ice Slabs, Federico Covi

Geosciences

Increased surface melt in the percolation zone of Greenland causes significant changes in the firn structure, directly affecting the surface mass balance of the ice sheet and the amount and timing of meltwater runoff. Thick impermeable layers, referred to as ice slabs, are preventing melt water percolation and refreezing in the firn favoring lateral movement of water and direct runoff to the oceans. The objective of this dissertation is to enhance the understanding of these processes by modeling the surface energy balance and resulting melt, and investigating the spatial and temporal changes in firn surface properties and associated water movement …

Acoustic And Seismic Signature Of Sustained Volcanic Eruptions, Julia E. Gestrich

Geosciences

Volcanic eruptions of any size can pose a significant risk to the life and livelihood of humans, as well as to infrastructure and the economy. Understanding the dynamics of an eruption is crucial to providing timely and accurate assessments of the eruption and associated hazard. Ideally the monitoring of volcanic unrest and eruption dynamics is done remotely to minimize exposure to volcanologists and maximize the spatial monitoring coverage of instruments. Another important factor is to have real-time data to facilitate rapid analysis and interpretation. Seismic and acoustic (infrasound) waves have proven useful in terms of remote real-time volcano monitoring. However, …

Development Of A Muc1 Cancer Immunotherapy Using Complement Targeted Liposomes And Organoplatinum (Iv) Complex As An Effective Anticancer Drug, Ameneh Arabi

Chemistry and Biochemistry

The development of therapeutic and preventive cancer vaccines has been on the rise in the past decade. Extensive tumor antigen libraries supply researchers with a wide variety of targets for developing cancer vaccines. Cancer vaccines aim to induce tumor regression, eradicate tumors and establish lasting antitumor memory, while avoiding adverse reactions. However, achieving this goal is hampered by the challenges of finding tumor antigens to incite an effective immune response and creating an efficient delivery system to deliver the antigen to target cells. In this thesis, we discuss how to integrate Toll Like Receptor (TLR) agonists with a MUC1 cancer …

Effects Of Diet And Hibernation In Skeletal Muscle Performance, Jishnu K.S. Krishnan

Chemistry and Biochemistry

Hibernating animals, such as the arctic ground squirrel (AGS), are subjected to a wide range of temperature variations. During hibernation, when they are predominantly physically inactive, body temperature can drop as low as -3°C, while in summer, body temperature can climb as high as 40°C. Torpor is a state of inactivity in an animal induced by a lack of food, which is followed by a fall in body temperature and metabolic rate. Torpor lasts around 21 days in AGS, and the progression of torpor begins with early torpor, followed by mid and late torpor, and culminates with interbout arousal lasting …

Accuracy, Precision, And Efficiency: Comparing Mapping Techniques In Nixtun-Ch’Ich’, Petén, Guatemala, Gabriela Zygadlo

Theses and Dissertations

New archaeological survey technologies have transformed the way in which sites are mapped. Nixtun-Ch’ich’ in Petén, Guatemala has been surveyed in a variety of ways including a theodolite with an electronic distance measurement (EDM), total station (TS), laser imaging, detection and ranging (LiDAR), and photogrammetry. This paper aims to compare various mapping techniques and their accuracy, precision, and efficiency when pertaining specifically to mapping in Nixtun-Ch’ich’, Petén, Guatemala. The goal is to evaluate which technique is most efficient when mapping in the site by considering the variables of cost, time, and environment of the site. The paper also considers the …

Potential Benefits Of The Campus Outdoor Built Environment On Student Stress, Leading To Improved Retention, Kevin Dilliard

Graduate Liberal Studies Theses and Dissertations

University landscape managers often ask themselves, are they making a difference? Since what they do is not a revenue-generating department, how can they validate their true worth beyond making the campus beautiful, which is excellent, but what added value do they bring? As is common practice, when economic times get tough, the landscape department budget is one of the first to be cut, but is that the wisest thing to do? This research was intended to explore the concept that the services landscape managers provide have a return on investment by providing an environment in which students can thrive and …

Regression Modeling Of Complex Survival Data Based On Pseudo-Observations, Rong Rong

Statistical Science Theses and Dissertations

The restricted mean survival time (RMST) is a clinically meaningful summary measure in studies with survival outcomes. Statistical methods have been developed for regression analysis of RMST to investigate impacts of covariates on RMST, which is a useful alternative to the Cox regression analysis. However, existing methods for regression modeling of RMST are not applicable to left-truncated right-censored data that arise frequently in prevalent cohort studies, for which the sampling bias due to left truncation and informative censoring induced by the prevalent sampling scheme must be properly addressed. Meanwhile, statistical methods have been developed for regression modeling of the cumulative …

Understanding Your Cultural Identities: A Self-Study Of The Impact Of One’S Cultural Identities On Interpreting Interactions, Shelby L.W. Sammartino

Education Doctorate Dissertations

There is a disproportionality of students of color receiving office referrals for disrespect and defiance because disrespect and defiance are subjective in interpretation by teachers in the classroom. This self-study aims for the researcher to identify and understand the construction of their cultural identities, so they can determine how their cultural identities impact their interpretation of interactions with students concerning disrespect and defiance, how their cultural identities impact their choice of behavior management technique in interactions concerning disrespect and defiance, and how their cultural identities impact their discipline decisions in interactions concerning disrespect and defiance. The data to determine the …

Lens: A Novel Image Processing-Based Approach For Low-Cost Segmentation Of Computed Tomography Scans Of Lungs, Monica Hinga

Computer Science ETDs

A staggering amount of data has been collected and analyzed since the beginning of the COVID-19 pandemic. Some of that data, however, particularly computed tomography (CT) scans of lungs, are difficult to analyze computationally. Segmentation of COVID-19 lesions provides researchers with insights into where lesions form, their volume, and in the case of time course data, how lesions grow as disease progresses. Spatial information, which has received little attention in the literature, has the potential to provide valuable insight to within-host viral and immune dynamics. Unfortunately, state-of-the-art supervised deep learning methods require labeled data, which can be prohibitively expensive to …

Detecting Transient Events With Genetic Algorithms, Dylan G. Palmieri

Computer Science

Accurately detecting and analyzing events in a power system is a difficult, but important task. This project aims to determine whether genetic algorithms are viable - in terms of both accuracy and efficiency - for detecting these events in large sets of power systems data. Although power systems events are intially classified using a trigger-based system at the time of the event, this project aims to show that power systems can be broken down into their component parts (lineto-line voltage, current, etc.) and analyzed in isolation after the fact with similar accuracy. The system attempts to achieve this goal by …

I'M A Killer Whale: The Process Of Cultural Identity Development From The Perspectives Of Young Indigenous Children, Angela Lunda

Indigenous Studies

This qualitative single case study examined the phenomenon of cultural identity development from the perspective of young Indigenous children situated within the context of their southeast Alaskan community. Decades of assimilationist policies have eroded cultural identity among many Indigenous Alaskans, yet a strong cultural identity is known to be a protective factor for Indigenous peoples. Building on Indigenous identity development theory, the study sought to answer the research questions: (1) How do young children demonstrate their cultural identity through interactions on the Land? (2) How do community organizations support cultural identity development (CID) in young Indigenous children? (3) What role …

A Wiggle Around A Giant: Exploring The Hot Electrons Within The Io Torus, Drew Coffin

Physics

Jupiter exhibits a fundamental rotational periodicity known as System IV that has no widely-accepted explanation, yet is easily observed in ultraviolet emission from the plasma torus generated by the innermost Galilean moon Io. This periodicity around Jupiter maps to a persistent, radially independent subcorotation within the Io plasma torus. In this thesis, we explore the origin and consequences of this periodicity. Using an equatorial chemistry and diffusive transport model, we demonstrate that a prescribed hot electron population produces a coherent wave of heightened energy flow that induces a consistent subcorotation. This additional hot electron population is consistent with the energization …

Controllability Of Non-Self-Adjoint Systems Of Partial Differential Equations, Jeff Park

Mathematics and Statistics

In this dissertation, we first consider the problem of exact controllability of a system of N one-dimensional coupled wave equations when the control is exerted on a part of the boundary by means of one control. We provide a Kalman condition (necessary and sufficient) and give a description of the attainable set. The second problem we consider is the inverse problem for the vector Schrödinger equation on the interval with a non-self-adjoint matrix potential. In doing so, we prove controllability of the system and develop a method to recover spectral data from the system. Then, we solve the inverse problem …

Formation And Interrogation Of A Modeling Excel Database For Sorbent Preconcentrate With Gc/Ms, Lisa Caravello

Chemical and Biological Engineering ETDs

Volatile organic compounds (VOCs) are of great interest and the subject of much research, as they can be used in various applications. Preconcentrating this class of analytes is necessary as they can be elusive with simple sampling techniques. VOCs are often captured using sorbents in thermal desorption tubes as preconcentrates prior to analysis, commonly gas chromatography mass spectroscopy (GCMS). There are gaps in knowledge in behavior of materials used as sorbents i.e., if they will retain an analyte of interest appropriately. In this research I seek to eliminate speculation and unknown variables of analyte and sorbent combinations by creating a …

Sled Dogs As Gifts. An Ethnography Of Dog Exchanges Among Kennels In Alaska., Allison K. Cruz

Anthropology

This thesis investigates the social relationships that develop through the circulation of sled dogs among Alaskan kennels. It is based on multi-sited ethnographic fieldwork at racing events, in sled dog kennels, as well as semi-structured interviews around Fairbanks. The research is informed by anthropological literature on kinship, personhood, and gift-giving economies. It examines how sled dogs are acquired and exchanged in Alaska and offers a novel perspective on the value of dog bloodlines and the relationships that unite breeders, mushers and sled dogs. The main argument is that Alaskan sled dogs are exchanged as gifts (rather than commodities) with the …

Exploring The North American Arctic Benthos: Community Structure And Oil Degradation Potential Of Sediment Bacteria And Archaea, Alexis M. Walker

Marine Biology

The Chukchi and Beaufort seas benthic habitats are home to a multitude of ecologically and commercially important organisms that are subject to ongoing environmental changes, including the impacts of climate change and increased exposure to contaminants. Benthic bacteria and archaea can be considered biogeochemical engineers. They play a major role in organic matter (OM) degradation and nutrient cycling and their community structure can reflect changes in environmental conditions such as OM composition and quantity, nutrient availability, redox conditions, and natural/anthropogenic contaminants (e.g. petroleum hydrocarbons). Yet, sediment microbial communities have rarely been examined in these marginal seas of North American Arctic. …

Distribution Network Planning And Operation With Autonomous Agents, Abdulraheem Hassan Alobaidi

Electrical Engineering Theses and Dissertations

With the restructured power system, different system operators and private investors are responsible for operating and maintaining the electricity networks. Moreover, with incentives for a clean environment and reducing the reliance on fossil fuel generation, future distribution networks adopt a considerable penetration of renewable energy sources. However, the uncertainty of renewable energy sources poses operational challenges in distribution networks. This thesis addresses the planning and operation of the distribution network with autonomous agents under uncertainty. First, a decentralized energy management system for unbalanced networked microgrids is developed. The energy management schemes in microgrids enhance the utilization of renewable energy resources …

Orbital Angular Momentum Orthogonality-Based Crosstalk Reduction: Theory And Experiment, Unaiza Tariq

Electrical Engineering Theses and Dissertations

Full duplex communication systems allow a single channel to be used for simultaneous two-way communication, increasing spectral efficiency. However, full duplex communication systems suffer from the issue of self-interference between local transmitter and receiver antennas. Analog subtraction and signal processing methods have previously been used to reduce this problem. This dissertation proposes the use of waves carrying orbital angular momentum (OAM) to mitigate the problem of self-interference by offering a means of additional isolation between local antennas.

Orbital angular momentum has been widely studied both in the photonics and radio domain. The theoretically infinite orthogonal states of an OAM signal …

Development And Application Of A Design Flow For Photonic Integrated Circuits, Ifeanyi Achu

Electrical Engineering Theses and Dissertations

Silicon photonics allows for the fabrication of many optical elements on a single photonic integrated circuit (PIC). By taking advantage of the established foundry technology used in the CMOS and silicon’s high refractive index, high feature density manufacturing can be achieved in mass quantities. In CMOS fabrication, from conception of an electronic circuit to testing, the process of designing an electronic circuit is dictated by a design flow which has been developed over the course of decades. This flow includes circuit level design and simulation, layout of the circuit, layout and verification of the chip, fabrication, packaging, and testing. Given …

An Investigation Of The Role Of System Effectiveness In The Acquisition And Sustainment Of U.S. Defense Systems: 1958 To 2022, John Green

Operations Research and Engineering Management Theses and Dissertations

This dissertation investigates the role of the system effectiveness methodology in acquiring and sustaining U.S. military weapons systems from 1958 to 2021. The period of interest has seen numerous changes in both the acquisition process and the application of system effectiveness to acquisition and sustainment. Several of the changes were disruptive, including shifting acquisition and sustainment to a commercial paradigm and completely overhauling the approach to acquiring new systems. The method of inquiry integrated three qualitative methods–structured literature review, grounded theory analysis, and historiography–into an innovative approach for investigating the changes to system effectiveness. The database for the investigation was …

Jam – Winter 2022, Rafat Jan, Edwin Van Teijlingen, Kiran Mubeen, Abeer Musaddique

Journal of Asian Midwives (JAM)

No abstract provided.

Prioritizing Prosocial Behavior For Preschool Children: How Are Parents Affecting Psb Development?, Deborah Zupito

Doctorate in Education

Scholars and Early Childhood Education (ECE) professionals acknowledge the critical nature of prosocial behavior (PSB) skills in the lives of preschool-aged children. Research specifies that children lacking PSBs are socially and academically disadvantaged. Studies have shown that 30% of preschoolers exhibit negative emotional/social behavior, and 80% of preschool educators report negative social behaviors (NSBs) adversely affecting their jobs. It is well-researched that a child's earliest experiences shape social and emotional behaviors, explicitly parenting and the home environment; however, less research exists about parents' knowledge and perception of their role relating to PSB development in their child's life. This qualitative case …

Void-Semiconductor Gaas Photonic Crystal Surface-Emitting Lasers By Epitaxial Regrowth And Single-Epitaxy Methods, Kevin James Reilly

Nanoscience and Microsystems ETDs

Monolithic semiconductor lasers including edge-emitting lasers (EELs) and vertical-cavity surface-emitting lasers (VCSELs) fail to realize simultaneous achievement of both high-power high-quality beams due to intrinsic limitations of their resonant cavity. Photonic crystal surface emitting lasers (PCSELs) address these structural limitations through employment of a two-dimensional photonic crystal (PC) cavity that creates feedback at a single wavelength for laterally scalable devices. This function of the PC allows PCSELs to power scale with area while maintaining single-mode emission required for diffraction-limited beams. In this way, PCSELs fulfill an industry demand for high-power high-quality lasing from a single chip.

Early PCSELs were fabricated …

The Pain Of Helping: Crisis Response Teams Experiences With College Student Suicide, Audra E. Dowling

Graduate Theses, Dissertations, and Capstones

This qualitative multicase study explores the lived experiences of seven higher education professionals who serve or have served on a crisis response team at the time of a college student suicide. It asks the following research question: How has a college student suicide impacted the individual psychological needs (safety, trust, esteem, intimacy, control) of those serving on a crisis response team? Using constructivist self-development theory (McCann & Pearlman, 1990) as a lens, psychological needs have been analyzed as fulfilled needs or distorted needs across two interviews and three journaling prompts to assess the impact on seven participants in this qualitative …