Physical Sciences and Mathematics Commons^™

Maintenance Optimization In A Digital Twin For Industry 4.0, Abhijit Gosavi, Vy Khoi Le

Engineering Management and Systems Engineering Faculty Research & Creative Works

The advent of Internet of Things and artificial intelligence in the era of Industry 4.0 has transformed decision-making within production systems. In particular, many decisions that previously required significant human activity are now made automatically with minimal human intervention via so-called digital twins (DTs). In the context of maintenance and reliability modeling, this naturally calls for new paradigms that can be seamlessly integrated within DTs for decision-making. The input data for time to failure needed in reliability computations are directly collected from the work center in a digital setting and often do not satisfy a known distribution. A neural network …

U.S. Public Opinion Of Reproductive Control Options For Free-Roaming Horses On Western Public Lands, S. Nicole Frey, Jeffrey L. Beck, John Derek Scasta, Loretta Singletary

Human–Wildlife Interactions

Free-roaming horses (Equus ferus caballus; horses) inhabit public rangelands located primarily in 10 western U.S. states. Recent horse population increases are impacting rangeland ecosystems, native wildlife species and their habitats, and exacerbating conflicts with domestic livestock grazing. While contraceptives and physical sterilization are promising options to manage horse herd levels, public opinion concerning the use of fertility control is not well understood. To better inform policymakers, we completed a rigorous study of a random sample of public land stakeholders across the United States (n = 3,500) in 2020 using a Likert scale online survey to assess their …

Re-Storying Grant Creek: A Case Study Of Relational Dynamics On A Degraded Montana Stream, Seamus Rucci Land

Graduate Student Theses, Dissertations, & Professional Papers

The UN Decade on Ecosystem Restoration began in 2021, and after a history of contentious ethical debates, ecological restoration is increasingly portrayed as a viable framework for combating environmental degradation and supporting more healthy and stable social-ecological systems. The proposed ecological restoration of Grant Creek, a degraded stream near Missoula, Montana, offers an opportunity to connect a restoration site to the broader, rapidly growing field of restoration practice. It also allows the opportunity to forward the ‘relational turn’ proposed by many in the sustainability sciences as an ontological and methodological means to move beyond positivist portrayals of social-ecological systems, which …

Formulation, Structure, And Applications Of Therapeutic, Amino Acid, And Water-Based Deep Eutectic Solvents, Md Sajjadur Rahman

Electronic Theses and Dissertations

In the design of greener chemicals, deep eutectic solvents (DESs) are considered as one of the most versatile alternative solvents with widespread applications. DESs have the advantages of being nonflammable with negligible vapor pressure compared to traditional solvents. They share many characteristics of ionic liquids, but DESs are cheaper to formulate, typically nontoxic, recyclable, biodegradable, and are suitable for use with biological systems. In my Ph.D. research, three types of emerging and unconventional types of DESs, namely therapeutic DES (THEDES), amino acid-based DES (AADES), and water-based DES (WDES), have been investigated. To formulate these DES easily available and cheaper chemicals, …

Soil Hydro-Physical Properties, Computed Tomography Measured Pore Parameters, And Soil Health Indicators As Influenced By Tillage And Crop Rotation Systems, Goutham Thotakuri

Electronic Theses and Dissertations

Long-term tillage and crop rotation systems are important agricultural management practices as these can have direct impact on the soil’s key properties. The objectives of this study were to (ⅰ) quantify the soil pore characteristics under long-term tillage and crop rotation using X-ray computed tomography (XCT) and to assess the relationships between XCT-measured pore parameters and soil hydro-physical properties; and (ⅱ) evaluate the impacts of long-term tillage and crop rotation on select soil health indicators. The objective (ⅰ) was carried out at Haskell Agricultural Laboratory (HAL), Concord, NE; and objective (ⅰi) was carried out at South Central Agricultural Laboratory (SCAL), …

Study On Performance Of Pruned Cnn-Based Classification Models, Mengling Deng

Electronic Theses and Dissertations

Convolutional Neural Network (CNN) is a neural network developed for processing image data. CNNs have been studied extensively and have been used in numerous computer vision tasks such as image classification and segmentation, object detection and recognition, etc. [1] Although, the CNNs-based approaches showed humanlevel performances in these tasks [2], they require heavy computation in both training and inference stages, and the models consist of millions of parameters. This hinders the development and deployment of CNN-based models for real world applications. Neural Network Pruning and Compression techniques have been proposed [3, 4] to reduce the computation complexity of trained CNNs …

It's Not Just No-Till: Crop Rotations Are Key To Improving Soil Quality And Grain Yields At Dakota Lakes Research Farm, Natalie Sturm

Electronic Theses and Dissertations

No-till is increasingly promoted as a vital agricultural practice to address the challenge of improving soil quality while maintaining the ability to produce food, feed, fuel, and fiber. However, questions remain regarding 1) how different crop rotations impact soil quality under no-till management specifically and 2) whether significant improvements in soil quality can be made without negatively impacted crop yields. In this study, we demonstrate that even under the same long-term no-till management, differences in grain yields and soil biological, chemical, and physical properties exist between crop rotations at Dakota Lakes Research Farm in central South Dakota. We propose that …

Combining Soil Health And Fertility Measurements To Improve The Accuracy Of Predicting Corn Grain Yield Responses To P And K Fertilization, Benjamin Groebner

Electronic Theses and Dissertations

Researchers have pointed to changes in climate and land management practices to justify the need to reevaluate the accuracy of current South Dakota (SD) corn (Zea mays L.) P and K fertilizer recommendations. Also, an increase in soil health understanding has created the potential for soil health measurements to be used to improve the accuracy of these recommendations. The objectives for this study were to 1) evaluate the current P and K critical values and 2) determine the effect of including soil health indicators on improving fertilizer recommendation accuracy. This project was conducted throughout central and eastern SD from 2019-2021 …

Disentangling The Complex Evolutionary History Of Invasive Russian Thistle: Phylogenetic Relationships, The Role Of Hybridization, And Public Engagement, Deva Raj Khanal

Electronic Theses and Dissertations

Invasive species are forces of environmental, economic, and social change with detrimental impacts on ecosystems, commerce, agriculture, and human health. However, we still have a poor understanding of the processes that could be driving invasive potential. Hybridization may contribute to the establishment and spread of invasive lineages, as it may enhance genetic variation and facilitate rapid adaptation. Focusing on Russian thistle (Salsola tragus s.l., family Amaranthaceae) and closely related species, my thesis aims to clarify phylogenetic relationships and investigate how hybridization has shaped the invasion dynamics of these lineages. Known as one of the fastest plant invasions in the United …

A Post-Pneumonia Epizootic Evaluation Of The Rapid City, South Dakota Bighorn Sheep Herd, Amanda N. Ensrud

Electronic Theses and Dissertations

Pneumonia is a major factor affecting populations of free-ranging bighorn sheep (Ovis canadensis) across western North America. Pneumonia can occur in large-scale epizootics, during which greater than half of the population typically dies. After these epizootics, surviving ewes continue to conceive and bear lambs. However, lamb recruitment may remain low due to periodic or annual pneumonia outbreaks causing high lamb mortality rates, sometimes greater than 90%. Our study focused on the Rapid City, South Dakota bighorn sheep (BHS) herd that has recorded pneumonia-induced population decline since 2009. The first objective was to improve lamb health and survival by identifying and …

Post-Fledging Habitat Selection And Movements Of Juvenile Mallards In The Prairie Pothole Region, Cynthia E. Anchor

Electronic Theses and Dissertations

The Prairie Pothole Region (PPR) of North America provides critical habitat for waterfowl across life stages, but anthropogenic changes to the landscape have negatively impacted habitat quality for waterfowl. The mallard (Anas platyrhynchos) is abundant and socioeconomically valuable in the PPR, as it is a preferred target species of waterfowl hunters. Extensive research has evaluated breeding ecology of mallards in the PPR, but the period between juvenile mallards fledging and migrating has rarely been studied. The post-fledging ecology of juvenile mallards is a vital consideration for comprehensive waterfowl management. Further, juvenile mallards are a significant portion of hunter harvest at …

Northern Great Plains Saline Sodic Soil Development, Classification, Remediation, And Management., Shaina Westhoff

Electronic Theses and Dissertations

Soil salinity and sodicity are issues of growing concern in the United States (U.S.) and globally. Knowledge gaps for glaciated, dryland salt-affected soils exist because much original salinity and sodicity research focused on irrigated systems. Land managers are being asked to produce food, feed, fiber, and fuel for an expanding global population. The number of land managers and crop advisors who are affected by these soils is increasing. Addressing salinity and sodicity knowledge gaps will be critical for their success. Salinity and sodicity have been impeding crop productivity since the advent of cultivation. Saline and sodic soils form via multiple …

Dynamics Of Mutualism In A Two Prey, One Predator System With Variable Carrying Capacity, Randy Huy Lee

UNF Graduate Theses and Dissertations

We considered the livelihood of two prey species in the presence of a predator species. To understand this phenomenon, we developed and analyzed two mathematical models considering indirect and direct mutualism of two prey species and the influence of one predator species. Both types of mutualism are represented by an increase in the preys' carrying capacities based on direct and indirect interactions between the prey. Because of mutualism, as the death rate parameter of the predator species goes through some critical value, the model shows transcritical bifurcation. Additionally, in the direct mutualism model, as the death rate parameter decreases to …

Bounded-Degree Plane Geometric Spanners: Connecting The Dots Between Theory And Practice, Matthew Alexander Graham

UNF Graduate Theses and Dissertations

The construction of bounded-degree plane geometric spanners has been a focus of interest since 2002 when Bose, Gudmundsson, and Smid proposed the first algorithm to construct such spanners. To date, eleven algorithms have been designed with various trade-offs in degree and stretch factor. We have implemented these sophisticated algorithms in C++ using the CGAL library and experimented with them using large synthetic and real-world pointsets. Our experiments have revealed their practical behavior and real-world efficacy. We share the implementations via GitHub for broader uses and future research.

We present a simple practical algorithm, named AppxStretchFactor, that can estimate stretch factors …

Measuring Vegetation Density In Marsh Grass Photographs Using Convolutional Neural Networks, Lucas W. Welch

UNF Graduate Theses and Dissertations

A marsh is a wetland dominated by various species of grasses rather than trees. It supports an important ecosystem, providing habitats for many kinds of animals and posing a crucial impact on coastal climates. Marshes are rapidly changing, and it is vital for scientists to track these changes to understand the health of them. To do so, biologists perform vegetation monitoring to estimate the coverage of vegetation in an area of marsh. This task often calls for extensive human labor carefully examining pixels in photos of marsh sites to calculate vegetation density for a variety of marsh grass species. This …

Frequent Mental Distress Among Adults In The United States And Its Association With Socio-Demographic Characteristics, Unhealthy Lifestyle, And Chronic Physical Health Status, Mamunur Rashid, M. Mazharul Islam, Aiping Li, Naima Shifa

Mathematics Faculty Publications

Frequent mental distress (FMD) is a measure of poor mental health days for at least 14 days out of 30 days. It is one of the important dimensions of the health-related quality of life. The underlying causes of FMD are diverse. However, the issue has not been explored extensively due to the lack of reliable data on mental health. The aim of this study was to examine the level and trends of FMD among the adults of the United States (US) and identify the socio-demographic, lifestyles, and chronic health outcomes related correlates of FMD. The data for the study was …

Preliminary Studies Of Background Rejection Capabilities For The Southern Wide−Field Gamma−Ray Observatory, Sonali Mohan

Dissertations, Master's Theses and Master's Reports

The Southern Wide-field Gamma-ray Observatory (SWGO), is a next-generation
gamma-ray observatory to be constructed in the Southern Hemisphere that will com-
plement current and future instruments by providing a wide-field coverage of a large
portion of the southern sky and a better sensitivity to the 100 GeVs to few PeVs
photon band to understand extreme astrophysical phenomena throughout the uni-
verse. Air shower events initiated by gamma rays will be recorded by the detector
and reconstructed to extract shower properties. The challenge for air-shower arrays
in the observation of gamma-ray sources is the large background of hadronic cos-
mic rays. …

Building Interest And Knowledge In Geosciences Through Place- & Field-Based Teacher Professional Learning Programs: A Comparative Multi-Case Study, Emily Gochis

Dissertations, Master's Theses and Master's Reports

The focus of this study was to develop and evaluate a geoscience professional development model that would improve K-12 teachers’ capacity to effectively build geoscience literacy and interests in students from a variety of settings and cultural groups. The research compared the application of a geoscience professional development model realized through multiple case studies of varying settings and scales. The study investigated the capacity of each approach in improving teachers’ geoscience background knowledge, awareness of local geologically and culturally significant examples, and ability to integrate place-based, field investigations into standards-based curricula. By using both qualitative and quantitative methodologies, the study …

Optical And Single Particle Properties Of North Atlantic Free Tropospheric Aerosols And Implications For Aerosol Direct Radiative Forcing, Megan Morgenstern

Dissertations, Master's Theses and Master's Reports

Human-induced climate change has steadily become a reality rather than a possibility. One factor that plays into climate change is radiative forcing due to aerosol-radiation interactions (ARI). As such, it is important to understand how aerosols (atmospheric particles) interact with solar radiation. This work looks at seven samples of well-aged aerosols (aerosols traveling in the atmosphere for at least a few days) collected at Pico Mountain Observatory in the summer of 2015. Pico Mountain Observatory is located in a remote, high elevation site in the Azores, in the Eastern-North Atlantic Ocean. The goals of the study were to analyze the …

Searching For Anomalous Extensive Air Showers Using The Pierre Auger Observatory Fluorescence Detector, Andrew Puyleart

Dissertations, Master's Theses and Master's Reports

Anomalous extensive air showers have yet to be detected by cosmic ray observatories. Fluorescence detectors provide a way to view the air showers created by cosmic rays with primary energies reaching up to hundreds of EeV . The resulting air showers produced by these highly energetic collisions can contain features that deviate from average air showers. Detection of these anomalous events may provide information into unknown regions of particle physics, and place constraints on cross-sectional interaction lengths of protons. In this dissertation, I propose measurements of extensive air shower profiles that are used in a machine learning pipeline to distinguish …

Preparation Of Ion-Selective Membrane And Electrode Using Cobalt Porphyrin As Ionophore For Anion Detection, Kawisara Longsakpreecha

Chulalongkorn University Theses and Dissertations (Chula ETD)

In this study, the synthesis of the 5,10,15,20-tetrakis(4-dodecyloxyphenyl)porphyrin cobalt(II) complex (CoL) was carried out through a condensation reaction of 4-n-dodecyloxybenzaldehyde and pyrrole, followed by the metalation reaction of cobalt(II) acetate with meso-tetra(4-alkyloxyphenyl) porphyrin (L2) to obtain CoL. Characterization of CoL was conducted using physical methods such as 1H-NMR, 13C-NMR, and MALDI-TOF to confirm CoL structure and purity. CoL was utilized as an ionophore to fabricate the ion selective membrane (ISM) and ion selective electrode (ISE) for the detection of ClO4-. The composition of the ISM, including polymer (PVC), plasticizer (NPOE), cationic additive (TDMACl), and ionophore (CoL), was optimized for ISE …

Characterizing Properties Of Implicit Dependence Copulas And Extreme Copulas, Noppawit Yanpaisan

Chulalongkorn University Theses and Dissertations (Chula ETD)

No abstract provided.

Virtual Machine Introspection Tool Design Analysis, Justin Martin

Dissertations, Master's Theses and Master's Reports

Virtual machines are an integral part of today’s computing world. Their use is widespread and applicable in many different computing fields. With virtual machines, the ability to introspect and monitor is often overlooked or left unimplemented. Introspection is used to gather information about the state of virtual machines as they operate. Without introspection, verbose log data and state information is unavailable after unexpected errors or crashes occur. With introspection, this data can be analyzed further to determine the true cause of the unexpected crash or error. Therefore, introspection plays a critical role in portraying accurate historical information regarding the operating …

Maximum Likelihood Estimator Method To Estimate Flaw Parameters For Different Glass Types, Nabhajit Goswami

Dissertations, Master's Theses and Master's Reports

Glass is commonly used in architectural applications, such as windows and in-fill panels and structural applications, such as beams and staircases. Despite the popularity of structural glass use in buildings, an engineering design standard to determine the required component or member strength for design loads does not exist. Glass is a brittle material that lacks a well-defined yield or ultimate stress, unlike ductile materials. The traditional engineering methods used to design a ductile material cannot be used to design a glass component. Glass fails in tension primarily due to the presence of microscopic flaws present on the surface that acts …

A Global Survey Of Volcanic So2 Emissions And Heat Flux Measured From Space, Nelmary Rodríguez-Sepúlveda

Dissertations, Master's Theses and Master's Reports

Over the past two decades, the availability of satellite measurements of volcanic gas emissions and heat flux has driven the development of new methodologies to improve global-scale volcano monitoring. In this work we explored the relationship between volcanic sulfur dioxide (SO₂) emissions and radiant heat flux (RHF) measurements from NASA’s Ozone Monitoring Instrument (OMI) and Moderate Resolution Imaging Spectroradiometer (MODIS), respectively, to gain insight into how it associates to volcanic processes and eruption styles. The OMI SO₂ emissions data are derived from existing databases developed by using the methodology in Fioletov et al. (2016), which contain global, …

Collective Hydrodynamics Of Robotic Fish, Rohit S. Pandhare

Dissertations, Master's Theses and Master's Reports

Many animals in nature travel in groups either for protection, survival, or endurance. Among these, fish do so under the burden of hydrodynamic loads, which incites questions as to the significance of the multi-body fluid-mediated interactions that facilitate collective swimming. We study such interactions in the idealized setting of a rotational array of robotic fish whose tails undergo a prescribed flapping motion, but whose swimming speed is determined as a natural result of the hydrodynamic effects. Specifically, we examine how the measured collective speed of the swimmers varies with the imposed frequency and amplitude of their tail flapping, and with …

Machine Learning-Driven Surrogate Models For Electrolytes, Tong Gao

Dissertations, Master's Theses and Master's Reports

We have developed a lattice Monte Carlo (MC) simulation based on the diffusion-limited aggregation model that accounts for the effect of the physical properties of ionic liquids (ILs) on lithium dendrite growth. Our simulations show that the size asymmetry between the cation and anion, the dielectric constant, and the volume fraction of ILs are critical factors to significantly suppress the dendrite growth, primarily due to substantial changes in electric-field screening. Specifically, the volume fraction of ILs has the optimal value for dendrite suppression. The present simulation method indicates potential challenges for the model extension to macroscopic systems. Therefore, we also …

Synthetic Augmentation Methods For Object Detection In Overhead Imagery, Nicholas R. Hamilton

Dissertations, Master's Theses and Master's Reports

The multidisciplinary area of geospatial intelligence (GEOINT) is continually changing and becoming more complex. From efforts to automate portions of GEOINT using machine learning, which augment the analyst and improve exploitation, to optimizing the growing number of sources and variables, there is no denying that the strategies involved in this collection method are rapidly progressing. The unique and inherent complexities involved in imagery analysis from an overhead perspective--—e.g., target resolution, imaging band(s), and imaging angle--—test the ability of even the most developed and novel machine learning techniques. To support advancement in the application of object detection in overhead imagery, we …

Toward Deep Learning Emulators For Modeling The Large-Scale Structure Of The Universe, Neerav Kaushal

Dissertations, Master's Theses and Master's Reports

Multi-billion dollar cosmological surveys are being conducted almost every decade in today’s era of precision cosmology. These surveys scan vast swaths of sky and generate tons of observational data. In order to extract meaningful information from this data and test these observations against theory, rigorous theoretical predictions are needed. In the absence of an analytic method, cosmological simulations become the most widely used tool to provide these predictions in order to test against the observations. They can be used to study covariance matrices, generate mock galaxy catalogs and provide ready-to-use snapshots for detailed redshift analyses. But cosmological simulations of matter …

The Variability Of The Saturation Ratio In Clouds, Jesse C. Anderson

Dissertations, Master's Theses and Master's Reports

The saturation ratio determines the growth of cloud droplets by condensation and activation of aerosol particles. In a uniform environment, the interactions between the saturation ratio and cloud droplets are well understood. However, the presence of turbulent mixing causes spatial and temporal variability in the temperature, water vapor and the saturation ratio. When applied to a cloud, the variability in S has been shown to broaden the cloud droplet size distribution through each droplet having its own growth rate and history. When droplets grow by condensation or evaporation, water vapor and heat feedback with the environment, altering the distribution of …