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Investigating The Effect Of Relative Humidity On Organic New Particle Formation From The Dark Ozonolysis Of Biogenic Volatile Organic Compounds, Austin Callum Flueckiger

Graduate College Dissertations and Theses

Solid or liquid particulate matter suspended in the air, also known as atmospheric aerosols, are a ubiquitous component of Earth’s atmosphere. It is important to understand the chemical and physical processes that lead to the formation of these aerosols as they have an impact on climate health and human health. An important subset of atmospheric aerosols are secondary organic aerosols (SOA) that form from the gas-phase oxidation of volatile organic compounds (VOCs). VOCs can be emitted via biogenic and anthropogenic pathways, however, global estimates place biogenic sources as the major contributor. Although widely studied, some of the fundamental mechanisms that …

Edge Colored And Edge Ordered Graphs, Per Gustin Wagenius

Graduate College Dissertations and Theses

In this work, the current state of the field of edge-colored graphs is surveyed. Anew concept of unshrinkable edge colorings is introduced which is useful for rainbow subgraph problems and interesting in its own right. This concept is analyzed in some depth. Building upon the linear edge ordering described in a recent work from Gerbner, Methuku, Nagy, Pálvölgyi, Tardos, and Vizer, edge-ordering graphs with the cyclic group is introduced and some results are given on this and a related counting problem.

Effective Drag Coefficient Prediction On Single-View 2d Images Of Snowflakes, Cameron Hudson

Graduate College Dissertations and Theses

The drag coefficient of snowflakes is an crucial particle descriptor that can quantify the relationships with the mass, shape, size, and fall speed of snowflake particles. Previous studies has relied on estimating and improving empirical correlations for the drag coefficient of particles, utilizing 3D images from the Multi-Angled Snowflake Camera Database (MASCDB) to estimate snowflake properties such as mass, geometry, shape classification, and rimming degree. However, predictions of the drag coefficient with single-view 2D images of snowflakes has proven to be a challenging problem, primarily due to the lack of data and time-consuming, expensive methods used to estimate snowflake shape …

Robust Interventions In Network Epidemiology, Erik Weis

Graduate College Dissertations and Theses

Which individual should we vaccinate to minimize the spread of a disease? Designing optimal interventions of this kind can be formalized as an optimization problem on networks, in which we have to select a budgeted number of dynamically important nodes to receive treatment that optimizes a dynamical outcome. Describing this optimization problem requires specifying the network, a model of the dynamics, and an objective for the outcome of the dynamics. In real-world contexts, these inputs are vulnerable to misspecification---the network and dynamics must be inferred from data, and the decision-maker must operationalize some (potentially abstract) goal into a mathematical objective …

Role Of Relative Humidity In New Particle Formation From Ozonlysis Of Atmospheric Volatile Organic Compounds, Christopher Snyder

Graduate College Dissertations and Theses

The impact of relative humidity (RH) on organic new particle formation (NPF) from ozonolysis of biogenic volatile organic compounds (BVOCs) remains an area of active debate. Previous reports provide contradictory results indicating both depression and enhancement of NPF under conditions of moderate RH, while others ignore the potential impact. Only several reports have suggested that the effect may depend on absolute mixing ratio of the precursor volatile organic compound (VOC, ppbv). However, before any experiments could be completed, development of new methods was necessary to overcome the limitation of sampling ultrafine nanoparticles (<50 nm aerodynamic diameter) with aerosol mass spectrometry. This dissertation includes a report on a new Particle Growth Apparatus (PaGA) that artificially grows particles from as small as 17 nm to over 110nm. Considerable effort was made to identify the most suitable growth matrix (squalane) and optimize particle growth for reproducibility and sensitivity.

The PaGA was then utilized in the …

Employing Genetic Algorithms For Energy-Efficient Data Routing In Internet Of Things Networks, Farzana Akhter

Graduate College Dissertations and Theses

The Internet of Things (IoT) connects a vast number of smart objects for various applications,such as home automation, industrial control, and healthcare. The rapid advancement in wireless technologies and miniature embedded devices has enabled IoT systems to be deployed in various environments. However, the performance of IoT devices is limited because of the imbalance of data traffic on different router nodes. Nodes that experience high data volume will have a higher energy depletion rate and, as a result, will reach the end of their life quicker than other routers that have less data traffic. Genetic Algorithms are a well-known technique …

Organic Fouling Mitigation In Forward Osmosis Technology Through The Use Of Oscilatting Alternating Current Electric Fields, Logan Werner

Graduate College Dissertations and Theses

Forward osmosis (FO) is the term given to osmosis in water filtration applications. FO has many advantages to conventional membrane filtration processes. The lack of external pressure needed to force solvent through the membrane is dramatically decreased in FO, resulting in a lower cost of operation compared to reverse osmosis. Lower external pressures also result in decreased fouling on the membrane surface and improved permeate flux. Fouling is one of the foremost challenges within the membrane filtration industry and is one of the biggest contributors to operating costs. While FO results in less fouling than RO, fouling remains a major …

Computing The Canonical Ring Of Certain Stacks, Jesse Franklin

Graduate College Dissertations and Theses

We compute the canonical ring of some stacks. We first give a detailed account of what this problem means including several proofs of a famous historical example. The main body of work of this thesis expands on our article \cite{Franklin-geometry-Drinfeld-modular-forms} in describing the geometry of Drinfeld modular forms as sections of a specified line bundle on a certain stacky modular curve. As a consequence of that geometry, we provide a program: one can compute the (log) canonical ring of a stacky curve to determine generators and relations for an algebra of Drinfeld modular forms, answering a problem posed by Gekeler …

Community Science And Coyote Stories: Capturing And Communicating Nature's Non-Material Values For Use In Decision-Making, Joshua Wright Morse

Graduate College Dissertations and Theses

The reasons and ways that nature matters underlie every part of environmental decision-making. Yet, there are disparities in how different kinds of benefits from and values about nature are represented in policy and practice. This dissertation explores how decision-makers and community members value nature broadly and also in the context of a specific human-wildlife interaction in Vermont, United States.

In my first chapter, I conduct semi-structured interviews with environmental sector practitioners in Vermont to learn about their awareness of non-material values from nature. I find that practitioners talk readily about both material and non-material ecosystem services as well as multiple …

Ring Learning With Errors, Sarah Days-Merrill

Graduate College Dissertations and Theses

Over the last twenty years, lattice-based cryptosystems have gained interest due to their levelof security against attacks from quantum computers. The main cryptosystems are based on the hardness of Ring Learning with Errors (RLWE). The Learning with Errors (LWE) problems were first introduced in 2005 by Regev [Reg09] and in 2010, [LPR10] developed the Ring Learning with Errors (RLWE) problems as candidates for safe encryption against quantum computers. Let K be a number field with ring of integers OK. For a prime q, the RLWE problems rely on samples of the form (a, b) ∈ OK/qOK × OK/qOK where a …

A Computational Journey Through Conspiracy Theories: A Genealogical Approach, Mohsen Ghasemizade

Graduate College Dissertations and Theses

In an era where misinformation and conspiracy theories (CTs) proliferate, this study presents an approach to understanding and categorizing CTs through the development of a detailed `family tree'. By adopting different definitions, we explore CTs as efforts to explain events through the lens of hidden, malevolent forces, distinguishing between actual conspiracies and theoretical beliefs without empirical proof. Leveraging an analysis of 1769 articles from fact-checking websites and employing Keyphrase Extraction, we compiled a dataset that led to the identification of 769 unique conspiracies. A RoBERTa-based binary classifier was developed, achieving an F1 score of 87\%, to distinguish CTs from non-CT …

Unraveling Public Evacuation Likelihood: Structural Equation Models And The Extended Parallel Process Model In Focus, Molly Margaret Myers

Graduate College Dissertations and Theses

This study explores the intricate relationships between risk perception, efficacy appraisal, and evacuation likelihood in the context of flooding among the United States public. The Extended Parallel Process Model (EPPM) developed by Witte (1992) serves as the theoretical framework for this study, emphasizing the two-pronged appraisal process of threat and efficacy, influencing individual responses to risk messaging. Analysis of the data delves into the relationships between risk perception and evacuation likelihood, offering insights into the public's understanding of flood risk and readiness for impending flood events. This study used Structural Equation Modeling (SEM) to discern the impact of threat and …

Assessing The Impact Of An Intervention To Build Food Agency During Emerging Adulthood, Amy Finley

Graduate College Dissertations and Theses

Agriculture is an ancient human activity that has always changed the Earth. But the scale and scope of modern, industrialized agriculture is producing emergent problems in the food system, like unprecedented environmental degradation and high-calorie nutrient-poor diets that are driving poor health outcomes. Increasing cooking skills and the frequency of home cooking have been proposed as solutions to escalating rates of nutrition-related public health problems and may also be important to meeting diet-related sustainability goals like reducing meat consumption. Subsequently, the overarching aim of this thesis is to situate the importance of cooking as a strategy for food systems transformation, …