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The Architecture Of A Lower-Crustal Shear Zone And Evidence For Along-Strike Variations In Strain Localization And Partitioning, Fiordland, New Zealand, Peter Carl Lindquist

Graduate College Dissertations and Theses

Rocks exposed in Fiordland, New Zealand provide a record of magmatic and tectonic processes that were active in the middle to lower crust of a magmatic arc during the Early Cretaceous. The George Sound shear zone (GSSZ) is one expression of those processes, and is a steep, lower-crustal shear zone that accommodated oblique sinistral motion within the continental margin of Gondwana. I have compiled structural and petrologic observations from five field areas that span the 50 km length of the exposed GSSZ. Directional and orientation statistics allow me to compare the orientation of fabrics at each field area to characterize …

Evidence For Polyphase Deformation In The Shear Zones Bounding The Chester And Athens Domes, Southeastern Vermont, From 40ar/39ar Geochronology, Kristin Schnalzer

Graduate College Dissertations and Theses

The Chester and Athens Domes are a composite mantled gneiss dome in southeast Vermont. While debate persists regarding the mechanisms of dome formation, most workers consider the domes to have formed during the Acadian Orogeny. This study integrates the results of 40Ar/39Ar step-heating of single mineral grains, or small multigrain aliquots, with data from microstructural analyses from samples collected in multiple transects across the dome-bounding shear zone(s) in order to understand the relationship between metamorphism and deformation. Results from the sheared units along the north and south transects are presented from west to east. In the north, hornblende from the …

Assessing The Biogeochemical Drivers Of Dissolved Organic Carbon (Doc) In Forested Headwater Catchments: A Multi-Scaled Approach, Thomas Adler

Graduate College Dissertations and Theses

Variability in export of dissolved organic carbon (DOC) from forested headwater catchments has been attributed to an array of hydrologic, biotic and geochemical drivers. In the Northeast United States specifically, one of the most commonly cited drivers is recovery from acid rain. A major challenge in understanding DOC dynamics has been relating long-term regional trends and patterns to catchment-scale processes and we address this challenge by integrating data driven and experimental methods to analyze trends and processes across spatial scales. On the regional scale, we quantify long-term trends of stream DOC concentrations in USGS headwater catchments with flow adjusted Seasonal …

Sulfur And Selenium In Peptides And Proteins: Part I – Chemoselective Methods For Disulfide Bond Formation, Part Ii – Function Of Selenium In Enzymes., Emma Jean Ste.Marie

Graduate College Dissertations and Theses

Selenocysteine (Sec), the 21st proteogenic amino acid, was first identified in 1976 by Thressa Stadtman. In proteins, Sec replaces the far more common sulfur-containing amino acid cysteine (Cys). A key question since Stadtman’s discovery is: Why does Sec replace Cys? This question is especially relevant since Cys-orthologs of Sec-enzymes catalyze the identical reaction with only slightly reduced efficiency, and incorporation of Sec into a protein is much more complicated and bioenergetically costly compared to Cys. The study of selenoproteins is very difficult because Sec is incorporated into proteins by recoding a UGA stop codon as a sense codon. Production of …

From Tap To Table: Consumer Values, Producer Attitudes, And Vermont Maple Syrup In A Dynamic Landscape, Aidan Conor Mccracken

Graduate College Dissertations and Theses

Harvesting the sap of maple trees [Acer saccharum] for use in the production of syrups and sugars has a storied history stretching back to the pre-Columbian practices of North America’s indigenous peoples. Since its adaptation by European settlers in the late seventeenth century and into the present day, the production of maple syrup has become especially integral to the livelihoods and cultural identities of farmers in Vermont. While oftentimes esteemed as a timeless agrarian tradition, market forces and environmental changes have led maple syrup producers (or sugarmakers) to adopt new production practices that scarcely resemble the taps, buckets, and draft …

Who Performs Pro-Environmental Behaviors (Pebs) And Why? Examining The Impacts Of Motivation, Environmental Attitudes, Identity, And Climate Change Concerns On Intended And Actual Pebs, Roberta Sofia Molokandov

Graduate College Dissertations and Theses

In 2018, the Intergovernmental Panel on Climate Change (IPCC) warned that the world only has until 2030 to prevent global temperatures from rising an additional .5 degrees Celsius from greenhouse gas emissions to thwart the catastrophic damage that could follow such warming. To reduce the concentration of greenhouse gasses in the atmosphere and alleviate human pressure on the natural environment, collective action must occur across the globe by consumers and producers. However, not everyone feels concerned about climate change, identifies as an environmentalist, or believes they can make an impact and that it is their responsibility to do so. Environmental …

Numerical Simulations Of An Inductively Coupled Plasma Torch, Samuel Whitmore

Graduate College Dissertations and Theses

During entry into a planetary atmosphere, a blunt body (e.g. a spacecraft) traveling at hypersonic velocity creates a bow shock in front of it. In the highly energetic post shock environment, the body experiences heat transfer due to convective, chemical, and radiative processes. To protect the payload against this heating, a thermal protection system (TPS) is employed. Because a given propulsion system has a set amount of mass that it can launch to orbit, reducing the amount of mass used for TPS is desirable as this mass is freed up for mission-oriented payload. At the present, uncertainties in the flow …

Reference Governors For Time-Varying Systems And Constraints, Collin Freiheit

Graduate College Dissertations and Theses

Control systems are often subject to constraints imposed by physical limitations or safety considerations, and require means of constraint management to ensure the stability and safety of the system. For real-time implementation, constraint management schemes must not carry a heavy computational burden; however many of the current solutions are computationally unattractive, especially those with robust formulations. Thus, the design of constraint management schemes with low computational loads is an important and practical problem for control engineers. Reference Governor (RG) is an efficient constraint management scheme that is attractive for real-time implementation due to its low computational complexity and ease of …

Microwave Assisted Heating Of A Ferromagnetically-Doped Propellant For Small Satellites: An Efficacy Study, Thomas Joseph Heffernan

Graduate College Dissertations and Theses

In the interest of mitigating high launch costs, small satellites are often chosen as secondary payloads during launch operations. Their lower mission importance dictates stringent restrictions on the propulsion systems which can be implemented as they cannot contain combustible or toxic agents; a common solution to this prob- lem is implementation of micronozzles with cold-gas propellants in order to generate thrust. The present research explores the efficacy of leveraging microwave-assisted decomposition of a ’green’ chemical blowing agent, namely Azodicarbonamide, as a propellant for use in a microthruster. The thermal evolution of a heterogeneous ferromagnetic-doped propellant is analyzed numerically using COMSOL …

Energy Justice, Just Transitions, And Renewable Energy Policies: Examining Energy Transitions In The State Of Vermont, Walter Keady

Graduate College Dissertations and Theses

In the United States, sub-national state policies play outsized roles in renewable energy policy. Vermont is considered a leader in renewable energy transitions, exemplified by its goal of a 90% reduction in greenhouse gas emissions by 2050. While scholars have praised Vermont’s transition policies, few studies analyze it using energy justice or just transition principles. This is a crucial omission, as justice in energy transition has both moral and instrumental importance – unjust transitions may thwart themselves by failing to achieve widespread societal support. I make initial contributions to this study using original research conducted as a member of an …

Design For An Increasingly Protean Machine, Sam Kriegman

Graduate College Dissertations and Theses

Data-driven, rather than hypothesis-driven, approaches to robot design are becoming increasingly widespread, but they remain narrowly focused on tuning the parameters of control software (neural network synaptic weights) inside an overwhelmingly static and presupposed body. Meanwhile, an efflorescence of new actuators and metamaterials continue to broaden the ways in which machines are free to move and morph, but they have yet to be adopted by useful robots because the design and control of metamorphosing body plans is extremely non-intuitive. This thesis unites these converging yet previously segregated technologies by automating the design of robots with physically malleable hardware, which we …

Utilizing Machine Learning For Respiratory Rate Detection Via Radar Sensor, Anwar Elhadad

Graduate College Dissertations and Theses

In this research, we investigate a data processing method to capture the respiratory rate of a person by utilizing a doppler radar to monitor their body movement during respiration. We utilize a machine learning algorithm with a radar sensor to capture the chest movement of a person while breathing and determine the respiratory rate according to that movement. We are using a Random Forest classifier to distinguish between different classes of pulses. After that, the algorithm constructs a sinusoidal signal representing the breathing rate of the sample. By applying this technique, we can detect the breathing rate accurately for different …

Exciton Coherence In 1d Phthalocyanine Based Organic Crystalline Thin Films, Kimngan Burrill

Graduate College Dissertations and Theses

Quantum coherence plays a vital role in the excitonic properties of organic semiconductors. Several theoretical and experimental studies have shown an unprecedented role of coherence in charge transfer and transport processes, which in turn can improve the performance of electronic devices. Specifically, an enhancement of exciton coherence size can result in fast energy transport and efficient charge separation. The ability to tailor the design and performance of organic electronics based on exciton coherence effects represents the possibility of ultrafast electronic applications in communication and information technology.

The objective of this thesis is the excitonic coherence studies of 1D crystalline thin …

The Environmental Microbiome In A Changing World: Microbial Processes And Biogeochemistry, Stephanie Juice

Graduate College Dissertations and Theses

Climate change can alter ecosystem processes and organismal phenology through both long-term, gradual changes and alteration of disturbance regimes. Because microbes mediate decomposition, and therefore the initial stages of nutrient cycling, soil biogeochemical responses to climate change will be driven by microbial responses to changes in temperature, precipitation, and pulsed climatic events. Improving projections of soil ecological and biogeochemical responses to climate change effects therefore requires greater knowledge of microbial contributions to decomposition. This dissertation examines soil microbial and biogeochemical responses to the long-term and punctuated effects of climate change, as well as improvement to decomposition models following addition of …

Seasonal Water Column Dynamics Exert Strong Control On The Chemical Partitioning Of Benthic Phosphorus Pools Of Shallow Eutrophic Freshwater Systems, Meagan Leduc

Graduate College Dissertations and Theses

In shallow lake systems, phosphorus (P) availability to cyanobacteria populations is often controlled by the release (internal loading) or sequestration of sediment P. This study provides novel insight into the feedbacks between the water column and benthic P pools across multiple time scales and explain how these dynamics influence chemical partitioning of P in lake sediment. Phosphorus partitioning in seasonal sediment core time series collected from a shallow eutrophic bay of Lake Champlain were quantified with SEDEX and enzyme hydrolysis selective extraction schemes. Time series extraction data were interpreted with concurrent water column physical and biogeochemical monitoring data to examine …

Complex Systems Analysis In Selected Domains: Animal Biosecurity & Genetic Expression, Luke Trinity

Graduate College Dissertations and Theses

I first broadly define the study of complex systems, identifying language to describe and characterize mechanisms of such systems which is applicable across disciplines. An overview of methods is provided, including the description of a software development methodology which defines how a combination of computer science, statistics, and mathematics are applied to specified domains. This work describes strategies to facilitate timely completion of robust and adaptable projects which vary in complexity and scope. A biosecurity informatics pipeline is outlined, which is an abstraction useful in organizing the analysis of biological data from cells. This is followed by specific applications of …

The Energetic Consequences Of Winter Foraging For Northern Temperate Fish Species, Benjamin David Block

Graduate College Dissertations and Theses

The seasonal energy dynamics of temperate fishes will likely be affected by climate change, especially during the winter. To date, freshwater fish are understudied in winter compared to other aquatic organisms, and additional winter-focused studies are urgently needed. Recent research has demonstrated that some fish species are more active in winter than previously thought, therefore, an inquiry into the energetic contributions of winter foraging to the annual growth of freshwater fishes is needed prior to imminent changes in winter conditions. Here I have empirically shown that winter foraging behavior and seasonal energy dynamics likely depend on the thermal preference of …

Effects Of Winter Ticks And Internal Parasites On Moose Survival And Fecundity In Vermont, Usa, Jacob Richard Debow

Graduate College Dissertations and Theses

Moose (Alces alces) have experienced considerable declines along the periphery of their range in the northeastern United States. In Vermont, the population declined by approximately 44% from 2010 to 2017 despite minimal hunter harvest and adequate habitat. Populations in New Hampshire and Maine have shown similar declines, associated primarily with the impacts of winter ticks (Dermacentor albipictus). However, uncertainty exists about the effects of environmental and other parasite related conditions on moose survival and reproduction. I examined patterns of moose survival and productivity among a radio-collared population (n = 127) in Vermont from 2017 to 2019. In terms of productivity, …

Essays On Modeling And Analysis Of Dynamic Sociotechnical Systems, David Rushing Dewhurst

Graduate College Dissertations and Theses

A sociotechnical system is a collection of humans and algorithms that interact under the partial supervision of a decentralized controller. These systems often display in- tricate dynamics and can be characterized by their unique emergent behavior. In this work, we describe, analyze, and model aspects of three distinct classes of sociotech- nical systems: financial markets, social media platforms, and elections. Though our work is diverse in subject matter content, it is unified though the study of evolution- and adaptation-driven change in social systems and the development of methods used to infer this change.

We first analyze evolutionary financial market microstructure …

Planning For People In Communities And Outdoor Recreation Places: Fostering Community Cohesion, Shaping Place Meanings, And Exploring Imaginaries, Yumiko Jakobcic

Graduate College Dissertations and Theses

This dissertation examines people’s relationships to place and community. The papers are linked by three broad themes: 1) place meanings, 2) community connections to resource places, and 3) innovative qualitative research methodologies.

The first paper used ethnographic methods in a case study of Vermont’s Winooski Valley Park District to examine how regional park districts can strengthen community relationships. It explored how the district serves visitors and communities, stimulates community interactions and cohesion, and perceives the outcomes of these efforts. Results showed that regional park districts connect people with nature and with others across neighborhoods, communities, and regions. These unique places …

Chirality-Assisted Synthesis Of Single-Handed Freeform Helical Ladder Polymers, Kyle Everett Murphy

Graduate College Dissertations and Theses

In nature, shape defines function, and as such scientists have long since attempted to mimic nature in a pursuit to reach a similar level of fidelity. Complex macromolecular structures and shapes have been developed with interesting and unique functionalities—such as the design and synthesis of molecular machines. However, macromolecular structures such as these are difficult to synthesize. My work in the Schneebeli group builds upon this challenge, where I have developed a strategy to precisely control the shape of macromolecules to generate well-defined structures. This was accomplished with stereoisomerically pure triptycene-like derivatives as the building block pieces which have an …

Growth Evaluation And Standardized Assessment Of Juvenile Lake Trout In Lake Champlain, Pascal Dylan Wilkins

Graduate College Dissertations and Theses

Restoration and recovery of lake trout (Salvelinus namaycush) has been the focus of research and management in the Great Lakes and Lake Champlain since populations collapsed in the late 19th and 20th centuries. Wild juvenile lake trout recruitment was discovered in Lake Champlain in 2015 after 42 years of stocking efforts. Intensive biweekly bottom trawl sampling during the ice-free season was conducted from 2015 to 2018 to assess the extent of wild recruitment at three different sampling areas (north, central, south) of the Main Lake. The collection of wild and stocked lake trout in bottom trawls enabled analysis and comparison …

Investigations Of Pnictogen And Boron-Group Compounds Towards The Synthesis Of Group Iii/V Pre-Ceramic Molecules, Brandon James Ackley

Graduate College Dissertations and Theses

Semiconductor ceramics have been the subject of study for many years due to their usefulness in applications ranging from LED devices to computer chips. Despite the ubiquity of semiconductor ceramics in daily life, the synthesis and manufacturing of such devices is tedious, energy intensive, or have a high potential for danger. Manufacturing methods such as deposition require the use of toxic or pyrophoric gases as well as requiring the temperatures often exceeding 1,000 °C. One way to address the issues of toxicity and high thermal barriers can be found in the implementation of pre-ceramic materials; materials which are either molecular …

The Development And Expansion Of A Cationic 1,3-Diaza Claisen Rearrangement That Affords Guanidines, Jordan Tocher

Graduate College Dissertations and Theses

Guanidines are found readily in many natural product scaffolds and biological systems. However, the chemical makeup of the guanidines is such that synthesis of guanidine-containing molecules remains challenging. In 2004, the Madalengoitia group first reported a zwitterionic 1,3-diaza Claisen rearrangement that affords complex guanidines. This was later expanded from the initial strained-bridged bicyclic systems to systems that encompassed more linear precursors, positively charged intermediates, and compounds with ring-expansion applications.

Due to the historical precedent that introduction of a positive charge into a rearranging system can benefit the kinetics and thermodynamics of a reaction, experiments were designed in order to probe …

Using Chirality-Assisted Synthesis To Construct Light-Responsive, Freeform Helical Foldamers And Shape-Defined Polymers, Jessica Leigh Bocanegra

Graduate College Dissertations and Theses

Foldamers (i.e. polymers which fold into well-defined shapes) are able to imitate arrangements of proteins, nucleic acids, and polysaccharides. However, previously reported foldamers are limiting in their ability to bind a multitude of guests—mainly due to very rigid conformational skeletal structures. Additionally, these structures commonly rely on π-π stacking and hydrogen bonding to dictate their shapes. We now report a helical foldamer that has (i) the capacity to bind selectively around a myriad of molecules while (ii) still embodying a well-defined, synthetically-controlled shape. We were able to create such structures as single-handed helices with chirality-assisted synthesis (CAS, see: Angew. Chem. …

Co-Optimization Of A Robot's Body And Brain Via Evolution And Reinforcement Learning, Jack Felag

Graduate College Dissertations and Theses

Agents are often trained to perform a task via optimization algorithms. One class of algorithms used is evolution, which is ``survival of the fitness'' used to pick the best agents for the objective, and slowly changing the best over time to find a good solution. Evolution, or evolutionary algorithms, have been commonly used to automatically select for a better body of the agent, which can outperform hand-designed models. Another class of algorithms used is reinforcement learning. Through this strategy, agents learn from prior experiences in order to maximize some reward. Generally, this reward is how close the objective is to …

Extremal/Saturation Numbers For Guessing Numbers Of Undirected Graphs, Jo Ryder Martin

Graduate College Dissertations and Theses

Hat guessing games—logic puzzles where a group of players must try to guess the color of their own hat—have been a fun party game for decades but have become of academic interest to mathematicians and computer scientists in the past 20 years. In 2006, Søren Riis, a computer scientist, introduced a new variant of the hat guessing game as well as an associated graph invariant, the guessing number, that has applications to network coding and circuit complexity. In this thesis, to better understand the nature of the guessing number of undirected graphs we apply the concept of saturation to guessing …

The Circuit And Cocircuit Lattices Of A Regular Matroid, Patrick Mullins

Graduate College Dissertations and Theses

A matroid abstracts the notions of dependence common to linear algebra, graph theory, and geometry. We show the equivalence of some of the various axiom systems which define a matroid and examine the concepts of matroid minors and duality before moving on to those matroids which can be represented by a matrix over any field, known as regular matroids. Placing an orientation on a regular matroid allows us to define certain lattices (discrete groups) associated to the matroid. These allow us to construct the Jacobian group of a regular matroid analogous to the Jacobian group of a graph. We then …

Guide To Urban Gardening In Winooski Valley, Vermont, Grace Claire O'Neil

Graduate College Dissertations and Theses

Urban gardens have become a growing interest in the Burlington, Vermont area. As interest grows, soil management, amendment, and health are integral to garden productivity. A baseline of soil health for the Burlington Area Community Gardens was created. Explored hypotheses include how nutrient concentrations changed over time (2011 to 2018) in till and no-till scenarios.

Ten sites in the Winooski Valley area were soil sampled in the Fall of 2018, along with eight sites in the Chittenden County vicinity in the Spring of 2019 for comparison. Using the Modified Morgan’s Universal Extraction Solution, soil nutrients such as phosphorus (P), potassium …

Predicting Wildlife Distributions And Resilience Under Alternative Futures, Schuyler Pearman-Gillman

Graduate College Dissertations and Theses

In the northeastern United States, population expansion, climate change, land use, and land-use change all pose serious concerns for wildlife. Understanding the impacts of climate and land-use change on species distributions can help inform conservation decisions. Unfortunately, empirical data on distributions are limited for many wildlife species, making conservation planning challenging. This dissertation focuses on the use of expert opinion data for modeling wildlife distributions and evaluating the impacts of future climate and land-use changes. First, I implemented expert elicitation techniques to collect wildlife occurrence data for harvested species (n = 10) in the New England region. I then used …