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2022

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Articles 961 - 990 of 18300

Full-Text Articles in Physical Sciences and Mathematics

Soteriafl: A Unified Framework For Private Federated Learning With Communication Compression, Zhize Li, Haoyu Zhao, Boyue Li, Yuejie Chi Dec 2022

Soteriafl: A Unified Framework For Private Federated Learning With Communication Compression, Zhize Li, Haoyu Zhao, Boyue Li, Yuejie Chi

Research Collection School Of Computing and Information Systems

To enable large-scale machine learning in bandwidth-hungry environments such as wireless networks, significant progress has been made recently in designing communication-efficient federated learning algorithms with the aid of communication compression. On the other end, privacy-preserving, especially at the client level, is another important desideratum that has not been addressed simultaneously in the presence of advanced communication compression techniques yet. In this paper, we propose a unified framework that enhances the communication efficiency of private federated learning with communication compression. Exploiting both general compression operators and local differential privacy, we first examine a simple algorithm that applies compression directly to differentially-private …


Npgreat: Assembly Of The Human Subtelomere Regions With The Use Of Ultralong Nanopore Reads And Linked Reads, Eleni Adam, Desh Ranjan, Harold Riethman Dec 2022

Npgreat: Assembly Of The Human Subtelomere Regions With The Use Of Ultralong Nanopore Reads And Linked Reads, Eleni Adam, Desh Ranjan, Harold Riethman

Computer Science Faculty Publications

Background: Human subtelomeric DNA regulates the length and stability of adjacent telomeres that are critical for cellular function, and contains many gene/pseudogene families. Large evolutionarily recent segmental duplications and associated structural variation in human subtelomeres has made complete sequencing and assembly of these regions difficult to impossible for many loci, complicating or precluding a wide range of genetic analyses to investigate their function.

Results: We present a hybrid assembly method, NanoPore Guided REgional Assembly Tool (NPGREAT), which combines Linked-Read data with mapped ultralong nanopore reads spanning subtelomeric segmental duplications to potentially overcome these difficulties. Linked-Read sets of DNA sequences identified …


Statistical Analysis Of Aquifer Hydraulic Properties By A Continuous Pumping Tomography Test: Application To The Boise Hydrogeophysical Research Site, Kan Bun Cheng, Gedeon Dagan, Warren Barrash, Michael Cardiff, Avinoam Rabinovich Dec 2022

Statistical Analysis Of Aquifer Hydraulic Properties By A Continuous Pumping Tomography Test: Application To The Boise Hydrogeophysical Research Site, Kan Bun Cheng, Gedeon Dagan, Warren Barrash, Michael Cardiff, Avinoam Rabinovich

Geosciences Faculty Publications and Presentations

Characterizing aquifer heterogeneity is paramount for accurate flow and transport modeling. In this work, we present a new approach for statistical analysis of hydraulic properties in continuous pumping tomography tests of a phreatic aquifer. The method entails determining equivalent hydraulic conductivity (Keq), specific storage (Ss,eq), and specific yield (Sy,eq) at many locations in the field and then calculating statistical moments of the equivalent properties, assuming they are random space variables. Equivalent properties are defined as the ones pertinent to a homogeneous aquifer for which the head time …


Improved Computational Prediction Of Function And Structural Representation Of Self-Cleaving Ribozymes With Enhanced Parameter Selection And Library Design, James D. Beck Dec 2022

Improved Computational Prediction Of Function And Structural Representation Of Self-Cleaving Ribozymes With Enhanced Parameter Selection And Library Design, James D. Beck

Boise State University Theses and Dissertations

Biomolecules could be engineered to solve many societal challenges, including disease diagnosis and treatment, environmental sustainability, and food security. However, our limited understanding of how mutational variants alter molecular structures and functional performance has constrained the potential of important technological advances, such as high-throughput sequencing and gene editing. Ribonuleic Acid (RNA) sequences are thought to play a central role within many of these challenges. Their continual discovery throughout all domains of life is evidence of their significant biological importance (Weinreb et al., 2016). The self-cleaving ribozyme is a class of noncoding Ribonuleic Acid (ncRNA) that has been useful for …


Deep Learning Of Microstructures, Amir Abbas Kazemzadeh Farizhandi Dec 2022

Deep Learning Of Microstructures, Amir Abbas Kazemzadeh Farizhandi

Boise State University Theses and Dissertations

The internal structure of materials also called the microstructure plays a critical role in the properties and performance of materials. The chemical element composition is one of the most critical factors in changing the structure of materials. However, the chemical composition alone is not the determining factor, and a change in the production process can also significantly alter the materials' structure. Therefore, many efforts have been made to discover and improve production methods to optimize the functional properties of materials. The most critical challenge in finding materials with enhanced properties is to understand and define the salient features of the …


The U.S. Endangered Species Act And Agency Discretion: The Role Of Public Commenting During The Rulemaking Process, Krista Helmstadter Lyons Dec 2022

The U.S. Endangered Species Act And Agency Discretion: The Role Of Public Commenting During The Rulemaking Process, Krista Helmstadter Lyons

Boise State University Theses and Dissertations

The most recent International Union for Conservation of Nature (IUCN) Red List classifies 40,084 out of the 142,577 evaluated species as threatened with extinction, with 1,962 of those species identified in the United States. The U.S. Endangered Species Act (ESA) was enacted in 1973 to protect and recover threatened and endangered species from extinction. The ESA federal listing process can be lengthy and arduous, taking years for a species to be proposed for listing. During the process the U.S. Fish and Wildlife Service (FWS) seeks comments from the public and peer reviewers on the proposed rule. Previous research debates the …


Meshfree Methods For Pdes On Surfaces, Andrew Michael Jones Dec 2022

Meshfree Methods For Pdes On Surfaces, Andrew Michael Jones

Boise State University Theses and Dissertations

This dissertation focuses on meshfree methods for solving surface partial differential equations (PDEs). These PDEs arise in many areas of science and engineering where they are used to model phenomena ranging from atmospheric dynamics on earth to chemical signaling on cell membranes. Meshfree methods have been shown to be effective for solving surface PDEs and are attractive alternatives to mesh-based methods such as finite differences/elements since they do not require a mesh and can be used for surfaces represented only by a point cloud. The dissertation is subdivided into two papers and software.

In the first paper, we examine the …


Computer Ethics In Curriculum, Tiya Williams Dec 2022

Computer Ethics In Curriculum, Tiya Williams

Publications and Research

Ethics specifically in Computer Curriculum is a growing problem that has yet to be widely addressed. Although, start of computer ethics being taught has been traced back to the early 1940’s it has not been standardized or implemented in all computer curriculum. The objective of this research is to diagnose the reasons why ethics is so crucial in computer curriculum at all levels. I used surveys to investigate whether students were taught ethics in their computer curriculum. I also conducted surveys for professors at universities and colleges if they were taught ethics while obtaining their degree, as well as if …


Quantifying The Effect Of Disturbance On Native Mojave Desert Shrubs, Tamara J. Wynne Dec 2022

Quantifying The Effect Of Disturbance On Native Mojave Desert Shrubs, Tamara J. Wynne

UNLV Theses, Dissertations, Professional Papers, and Capstones

Disturbance can come in many different forms. In our studies, we looked at the impact of a solar photovoltaic facility on native plants growing inside and outside of the facility, alteration in precipitation (simulated) on four native shrubs and the impact of applying supplemental water as a function of volume and frequency to establish native shrubs such as might occur at restoration sites. Disturbance is becoming a more common phenomenon in many ecosystems throughout the world, increasing the need for studies that quantify the impact at the plant and ecosystem level. Each research project revealed different plant responses, such as …


Identification Of Factors Contributing To Traffic Crashes By Analysis Of Text Narratives, Cristian D. Arteaga-Sanchez Dec 2022

Identification Of Factors Contributing To Traffic Crashes By Analysis Of Text Narratives, Cristian D. Arteaga-Sanchez

UNLV Theses, Dissertations, Professional Papers, and Capstones

The fatalities, injuries, and property damage that result from traffic crashes impose a significant burden on society. Current research and practice in traffic safety rely on analysis of quantitative data from crash reports to understand crash severity contributors and develop countermeasures. Despite advances from this effort, quantitative crash data suffers from drawbacks, such as the limited ability to capture all the information relevant to the crashes and the potential errors introduced during data collection. Crash narratives can help address these limitations, as they contain detailed descriptions of the context and sequence of events of the crash. However, the unstructured nature …


Jiapi: A Type Checker Generator For Statically Typed Languages, Benjamin Cisneros Merino Dec 2022

Jiapi: A Type Checker Generator For Statically Typed Languages, Benjamin Cisneros Merino

UNLV Theses, Dissertations, Professional Papers, and Capstones

Type systems are a key characteristic in the context of the study of programming languages. They frequently offer a simple, intuitive way of expressing and testing the fundamental structure of programs. This is especially true when types are used to provide formal, machine-checked documentation for an implementation. For example, the absence of type errors in code prior to execution is what type systems for static programming languages are designed to assure, and in the literature, type systems that satisfy this requirement are referred to as sound type systems. Types also define module interfaces, making them essential for achieving and maintaining …


Transient Sources And How To Study Them: Selected Topics In Multi-Messenger Astronomy, Jiawei Luo Dec 2022

Transient Sources And How To Study Them: Selected Topics In Multi-Messenger Astronomy, Jiawei Luo

UNLV Theses, Dissertations, Professional Papers, and Capstones

The discovery of cosmic neutrino flux by IceCube, and the multi-messenger observations of gravitational event GW170817 ushered in the era of multi-messenger astronomy. Since the Universe itself is a natural laboratory, multi-messenger astronomy can help us study the most extreme physics processes in great detail. In this dissertation, we touch on some of the currently unanswered questions involving different types of transient sources and different “messengers” of multi-messenger astronomy. We employ a variety of analysis methods, including machine learning, a method that has not yet been widely adopted in astronomy but is rapidly gaining momentum.We start this dissertation with Chapter …


Along Strike Tectonic Evolution Of The Neogene Bermejo Foreland Basin And Eastern Precordillera Thrust Front, Argentina (30-32ºs), Zoey Catherine Plonka Dec 2022

Along Strike Tectonic Evolution Of The Neogene Bermejo Foreland Basin And Eastern Precordillera Thrust Front, Argentina (30-32ºs), Zoey Catherine Plonka

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Bermejo retroarc foreland basin system formed in flexural response to Miocene crustal thickening in the Andean orogenic system, specifically, the eastward propagation of the Precordillera fold-thrust belt and the basement-involved uplift of the Sierras Pampeanas. Previous work in the area has mainly focused on the mechanisms and expression of flat slab subduction and the structural geometry of the basement-involved Sierras Pampeanas and east-vergent Precordillera fold-thrust belt at depth. Much of this work has furthered the understanding of Bermejo basin evolution north of 31ºS, however debate still exists whether the N-S trending Bermejo basin evolved synchronously or asynchronously through time. …


Mesozoic Sevier Thrusts Overprinted By Miocene-Quaternary Left-Lateral Deformation: Structures And Tectonism Of The Kane Springs Wash Region, Nevada, Andrew Reid Dec 2022

Mesozoic Sevier Thrusts Overprinted By Miocene-Quaternary Left-Lateral Deformation: Structures And Tectonism Of The Kane Springs Wash Region, Nevada, Andrew Reid

UNLV Theses, Dissertations, Professional Papers, and Capstones

Recognizing how rifts develop through space and time is vital to enrich our understanding of continental breakup. Rifts are commonly segmented by transfer or accommodations zones that form as the rift develops due to differences in the onset, direction, magnitude, or rates of extension on either side of the transfer or accommodation zone. The Basin and Range province is a wide rift where Cenozoic extension overprints and exposes earlier Mesozoic Sevier fold-thrust belt shortening structures. This exposure allows Sevier thrust correlations between individual mountain ranges and use of these shortening structures to study rift segmentation by strike-slip transfer faults. The …


Enhanced Heart Rate Prediction Model Using Damped Least-Squares Algorithm, Angela An, Mohammad Al-Fawa’Reh, James Jin Kang Dec 2022

Enhanced Heart Rate Prediction Model Using Damped Least-Squares Algorithm, Angela An, Mohammad Al-Fawa’Reh, James Jin Kang

Research outputs 2022 to 2026

Monitoring a patient’s vital signs is considered one of the most challenging problems in telehealth systems, especially when patients reside in remote locations. Companies now use IoT devices such as wearable devices to participate in telehealth systems. However, the steady adoption of wearables can result in a significant increase in the volume of data being collected and transmitted. As these devices run on limited battery power, they can run out of power quickly due to the high processing requirements of the device for data collection and transmission. Given the importance of medical data, it is imperative that all transmitted data …


Age And Genesis Of W-Mo-Cu Mineralization, Gold Hill, Utah, Nathan J. Carey Dec 2022

Age And Genesis Of W-Mo-Cu Mineralization, Gold Hill, Utah, Nathan J. Carey

UNLV Theses, Dissertations, Professional Papers, and Capstones

Utah's Gold Hill mining district hosts a Jurassic felsic pluton (~80 km^2) that was emplaced into a Mississippian to Pennsylvanian carbonate-dominated sedimentary sequence and is spatially associated with numerous polymetallic mineral deposits. This study focuses on W-Mo-Cu mineralization at the Lucy L., Doctor, Yellow Hammer, Reaper, and Rustler deposits within the district. The new, detailed petrographic observations, mineral chemistry (on scheelite, molybdenite, chalcopyrite, magnetite, garnet, and pyroxene), and Re-Os molybdenite geochronological data presented here allows for the determination of key mineral associations and paragenesis, the characterization of deposit types and their evolution, and the constraining of the relative and absolute …


Real–Time Semantic Segmentation For Railway Anomalies Analysis, Paul Stanik Iii Dec 2022

Real–Time Semantic Segmentation For Railway Anomalies Analysis, Paul Stanik Iii

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the past few years, computer vision has made huge jumps due to deep learning which leverages increased computational power and access to data. The computer vision community has also embraced transparency to accelerate research progress by sharing open datasets and open source code. Access to large scale datasets and benchmark challenges propelled and opened the field. The autonomous vehicle community is a prime example. While there has been significant growth in the automotive vision community, not much has been done in the rail domain. Traditional rail inspection methods require special trains that are run during down time, have sensitive …


Chromophoric Dissolved Organic Matter And Dissolved Organic Carbon In Lakes Across An Elevational Gradient From The Mountains To The Sea, Kyle Juetten, Angela L. Strecker, Aaron Harrison, Zachary Landram, Warren J. De Bruyn, Catherine D. Clark Dec 2022

Chromophoric Dissolved Organic Matter And Dissolved Organic Carbon In Lakes Across An Elevational Gradient From The Mountains To The Sea, Kyle Juetten, Angela L. Strecker, Aaron Harrison, Zachary Landram, Warren J. De Bruyn, Catherine D. Clark

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Dissolved organic matter (DOM) in lakes across elevation gradients is a complex function of topography, climate, vegetation coverage, land use, and lake properties. To examine sources and processing of DOM from sea level to mountain lakes (3–1,574 m), we measured dissolved organic carbon (DOC) concentrations and chromophoric dissolved organic matter (CDOM) optical properties, lake characteristics, and water quality parameters in 62 freshwater lakes in the Pacific Northwest, USA. Higher elevation lakes had lower DOC concentrations and absorbance. These lakes had higher forest cover and minimal wetlands in their watershed, in addition to low nutrients, water temperatures, and chlorophyll a in …


External-Memory Dictionaries With Worst-Case Update Cost, Rathish Das, John Iacono, Yakov Nekrich Dec 2022

External-Memory Dictionaries With Worst-Case Update Cost, Rathish Das, John Iacono, Yakov Nekrich

Michigan Tech Publications

The Bϵ-tree [Brodal and Fagerberg 2003] is a simple I/O-efficient external-memory-model data structure that supports updates orders of magnitude faster than B-tree with a query performance comparable to the B-tree: for any positive constant ϵ < 1 insertions and deletions take O(B11-ϵ logB N) time (rather than O(logB N) time for the classic B-tree), queries take O(logB N) time and range queries returning k items take O(logB N + Bk) time. Although the Bϵ-tree has an optimal update/query tradeoff, the runtimes are amortized. Another structure, the write-optimized skip list, introduced by Bender et al. [PODS 2017], has the same performance as the Bϵ-tree but with runtimes that are randomized rather than amortized. In this paper, we present a variant of the Bϵ-tree with deterministic worst-case running times that are identical to the original’s amortized running times.


Estimating Sewage Flow Rate In Jefferson County, Kentucky, Using Machine Learning For Wastewater-Based Epidemiology Applications, Dhiraj Kanneganti, Lauren E. Reinersman, Rochelle H. Holm, Ted Smith Dec 2022

Estimating Sewage Flow Rate In Jefferson County, Kentucky, Using Machine Learning For Wastewater-Based Epidemiology Applications, Dhiraj Kanneganti, Lauren E. Reinersman, Rochelle H. Holm, Ted Smith

Faculty and Staff Scholarship

Direct measurement of the flow rate in sanitary sewer lines is not always feasible and is an important parameter for the normalization of data used in wastewater-based epidemiology applications. Machine learning to estimate past wastewater influent flow rates supporting public health applications has not been studied. The aim of this study was to assess wastewater treatment plant influent flow rates when compared with weather data and to retrospectively estimate flow rates in Louisville, Kentucky (USA), based on other data types using machine learning. A random forest model was trained using a range of variables, such as feces-related indicators, weather data …


Expressiveness Of Real-Time Motion Captured Avatars Influences Perceived Animation Realism And Perceived Quality Of Social Interaction In Virtual Reality, Alan D. Fraser, Isabella Branson, Ross C. Hollett, Craig P. Speelman, Shane L. Rogers Dec 2022

Expressiveness Of Real-Time Motion Captured Avatars Influences Perceived Animation Realism And Perceived Quality Of Social Interaction In Virtual Reality, Alan D. Fraser, Isabella Branson, Ross C. Hollett, Craig P. Speelman, Shane L. Rogers

Research outputs 2022 to 2026

Using motion capture to enhance the realism of social interaction in virtual reality (VR) is growing in popularity. However, the impact of different levels of avatar expressiveness on the user experience is not well understood. In the present study we manipulated levels of face and body expressiveness of avatars while investigating participant perceptions of animation realism and interaction quality when disclosing positive and negative experiences in VR. Moderate positive associations were observed between perceptions of animation realism and interaction quality. Post-experiment questions revealed that many of our participants (approximately 40 %) indicated the avatar with the highest face and body …


Trace Element Behaviors During Igneous Evolution And Hydrothermal Alteration Of An Evolved Rhyolite, The Blawn Formation, Wah Wah Mountains, Utah: Implications For Critical Metal Abundances In Highly Evolved Rhyolites, Drew William Barkoff Dec 2022

Trace Element Behaviors During Igneous Evolution And Hydrothermal Alteration Of An Evolved Rhyolite, The Blawn Formation, Wah Wah Mountains, Utah: Implications For Critical Metal Abundances In Highly Evolved Rhyolites, Drew William Barkoff

UNLV Theses, Dissertations, Professional Papers, and Capstones

A-type rhyolites and granites often contain elevated concentrations of the rare earth elements (REE) and many other critical trace elements relative to I- and S-type rhyolites and granites. Their trace element-enriched nature makes them potentially prospective bulk tonnage, low-grade resources of the REE and many other critical trace elements, including Li, Be, Mo, Sn, and W, but little work has been performed to delineate their economic potential. The 22.1 Ma Red Beryl Rhyolite (RBR) and the 18.3 Ma Tetons Rhyolite (TR) units of the Blawn Formation represent two A-type rhyolite domes located in the southern Wah Wah Mountains of Utah. …


Characterization Of The Isothermal Titration Calorimetry Single Injection Method Using T4 Polynucleotide Kinase As A Model System For Kinases, Rebecca Chaehee Lim Dec 2022

Characterization Of The Isothermal Titration Calorimetry Single Injection Method Using T4 Polynucleotide Kinase As A Model System For Kinases, Rebecca Chaehee Lim

UNLV Theses, Dissertations, Professional Papers, and Capstones

Kinases are an important class of enzymes involved in the regulation of different cellular processes. The dysfunctional activity, either hyperactivity or inactivity, of kinases has been associated with many types of diseases, making kinases a major therapeutic target. As of 2020, more than 80 kinase inhibitors have been FDA-approved and have revolutionized the treatment for progressive disorders such as cancers and Alzheimer's diseases. However, there is always the possibility of developing severe side effects or resistance to drugs so the search for new therapeutics must continue with efficiency and accuracy.Isothermal titration calorimetry (ITC) is a state-of-the-art technique specialized in detecting …


The Role Of Inputs Of Marine Wrack And Carrion In Sandy-Beach Ecosystems: A Global Review, Glenn A. Hyndes, Emma L. Berdan, Cristian Duarte, Jenifer E. Dugan, Kyle A. Emery, Peter A. Hamback, Christopher J. Henderson, David M. Hubbard, Mariano Lastra, Miguel A. Mateo, Andrew Olds, Thomas A. Schlacher Dec 2022

The Role Of Inputs Of Marine Wrack And Carrion In Sandy-Beach Ecosystems: A Global Review, Glenn A. Hyndes, Emma L. Berdan, Cristian Duarte, Jenifer E. Dugan, Kyle A. Emery, Peter A. Hamback, Christopher J. Henderson, David M. Hubbard, Mariano Lastra, Miguel A. Mateo, Andrew Olds, Thomas A. Schlacher

Research outputs 2022 to 2026

Sandy beaches are iconic interfaces that functionally link the ocean with the land via the flow of organic matter from the sea. These cross-ecosystem fluxes often comprise uprooted seagrass and dislodged macroalgae that can form substantial accumulations of detritus, termed ‘wrack’, on sandy beaches. In addition, the tissue of the carcasses of marine animals that regularly wash up on beaches form a rich food source (‘carrion’) for a diversity of scavenging animals. Here, we provide a global review of how wrack and carrion provide spatial subsidies that shape the structure and functioning of sandy-beach ecosystems (sandy beaches and adjacent surf …


Irreducible Representations From Group Actions On Trees, Charlie Liou Dec 2022

Irreducible Representations From Group Actions On Trees, Charlie Liou

Master's Theses

We study the representations of the symmetric group $S_n$ found by acting on

labeled graphs and trees with $n$ vertices. Our main results provide

combinatorial interpretations that give the number of times the irreducible

representations associated with the integer partitions $(n)$ and $(1^n)$ appear

in the representations. We describe a new sign

reversing involution with fixed points that provide a combinatorial

interpretation for the number of times the irreducible associated with the

integer partition $(n-1, 1)$ appears in the representations.


Predicting Startup Success Using Publicly Available Data, Emily Gavrilenko Dec 2022

Predicting Startup Success Using Publicly Available Data, Emily Gavrilenko

Master's Theses

Predicting the success of an early-stage startup has always been a major effort for investors and venture funds. Statistically, there are about 305 million total startups created in a year, but less than 10% of them succeed to become profitable businesses. Accurately identifying the signs of startup growth is the work of countless investors, and in recent years, research has turned to machine learning in hopes of improving the accuracy and speed of startup success prediction.

To learn about a startup, investors have to navigate many different internet sources and often rely on personal intuition to determine the startup’s potential …


Wildfire Spread Prediction Using Attention Mechanisms In U-Net, Kamen Haresh Shah, Kamen Haresh Shah Dec 2022

Wildfire Spread Prediction Using Attention Mechanisms In U-Net, Kamen Haresh Shah, Kamen Haresh Shah

Master's Theses

An investigation into using attention mechanisms for better feature extraction in wildfire spread prediction models. This research examines the U-net architecture to achieve image segmentation, a process that partitions images by classifying pixels into one of two classes. The deep learning models explored in this research integrate modern deep learning architectures, and techniques used to optimize them. The models are trained on 12 distinct observational variables derived from the Google Earth Engine catalog. Evaluation is conducted with accuracy, Dice coefficient score, ROC-AUC, and F1-score. This research concludes that when augmenting U-net with attention mechanisms, the attention component improves feature suppression …


Dual Energy Electron Storage Ring Cooler Design For Relativistic Ion Beams, Bhawin Dhital Dec 2022

Dual Energy Electron Storage Ring Cooler Design For Relativistic Ion Beams, Bhawin Dhital

Physics Theses & Dissertations

Collider experiments demand small beam emittances in order to achieve high luminosity. For light particles such as electrons, there exists a natural synchrotron radiation damping resulting in low emittance beams at equilibrium. In the case of heavy particle beams such as proton or ion beams, there is no significant synchrotron radiation damping effect and some cooling mechanism is needed to get to low emittance beams. A dual energy storage ring cooler is a novel concept proposed to cool hadron beams at higher energies. The design consists of two rings: a low energy ring and a high energy ring connected by …


Characterization Of Losses In Superconducting Radio-Frequency Cavities By Combined Temperature And Magnetic Field Mapping, Ishwari Prasad Parajuli Dec 2022

Characterization Of Losses In Superconducting Radio-Frequency Cavities By Combined Temperature And Magnetic Field Mapping, Ishwari Prasad Parajuli

Physics Theses & Dissertations

Superconducting radio-frequency (SRF) cavities are one of the fundamental building blocks of modern particle accelerators. To achieve the highest quality factors (1010-1011), SRF cavities are operated at liquid helium temperatures. Magnetic flux trapped on the surface of SRF cavities during cool-down below the critical temperature is one of the leading sources of residual RF losses. Instruments capable of detecting the distribution of trapped flux on the cavity surface are in high demand in order to better understand its relation to the cavity material, surface treatments and environmental conditions. We have designed, developed, and commissioned two novel …


Microplastic Accumulation In Terrestrial Gastropods And Soils, Gregory B. Bonilla Dec 2022

Microplastic Accumulation In Terrestrial Gastropods And Soils, Gregory B. Bonilla

Masters Theses

Microplastics (MPs) have become an emerging threat to ecosystems across the world. Transport, impacts, and fates are grossly understudied, especially in terrestrial environments. Current research on MP bioaccumulation has focused mainly on aquatic organisms with little study of terrestrial organisms, including snails where data are nearly nonexistent. To address this, we collected and examined land snails and their surrounding soil for MP content in shell and tissue. From September 11, 2020, to October 25, 2021, cover boards were placed (n=30) along relatively undisturbed sites in hardwood, forested areas, and tall grasses in a Wildlife Management Area (WMA) in Oak Ridge …