Physical Sciences and Mathematics Commons^™

Smart Classifiers And Bayesian Inference For Evaluating River Sensitivity To Natural And Human Disturbances: A Data Science Approach, Kristen Underwood

Graduate College Dissertations and Theses

Excessive rates of channel adjustment and riverine sediment export represent societal challenges; impacts include: degraded water quality and ecological integrity, erosion hazards to infrastructure, and compromised public safety. The nonlinear nature of sediment erosion and deposition within a watershed and the variable patterns in riverine sediment export over a defined timeframe of interest are governed by many interrelated factors, including geology, climate and hydrology, vegetation, and land use. Human disturbances to the landscape and river networks have further altered these patterns of water and sediment routing.

An enhanced understanding of river sediment sources and dynamics is important for stakeholders, and …

Some Results On A Class Of Functional Optimization Problems, David Rushing Dewhurst

Graduate College Dissertations and Theses

We first describe a general class of optimization problems that describe many natu- ral, economic, and statistical phenomena. After noting the existence of a conserved quantity in a transformed coordinate system, we outline several instances of these problems in statistical physics, facility allocation, and machine learning. A dynamic description and statement of a partial inverse problem follow. When attempting to optimize the state of a system governed by the generalized equipartitioning princi- ple, it is vital to understand the nature of the governing probability distribution. We show that optimiziation for the incorrect probability distribution can have catas- trophic results, e.g., …

Genetic And Demographic Consequences Of Lake And River Habitat Fragmentation On Fishes In Vermont, Peter T. Euclide

Graduate College Dissertations and Theses

Globally, habitat fragmentation has had a major impact on the conservation and management of many species and is one of the primary causes of species extinction. Habitat fragmentation is loosely defined as a process in which a continuous habitat is reduced to smaller, disconnected patches as the result of habitat loss, restriction of migration or the construction of barriers to movement. Aquatic systems are particularly vulnerable to habitat fragmentation, and today an estimated 48% of rivers are fragmented worldwide. My dissertation evaluates how habitat fragmentation has influenced the populations of four different species of fish in the Lake Champlain basin. …

Governing Environmental And Economic Flows In Regional Food Systems, Michael Bishop Wironen

Graduate College Dissertations and Theses

Globalization, specialization, and intensification have transformed the global food system, generating material flows and impacts that span multiple scales and levels, presenting novel governance challenges. Many argue for a transition toward a sustainable food system, although the scope and specific goals are fiercely contested. Theory and method is needed to evaluate competing normative claims and build legitimacy.

In this dissertation Vermont serves as a case study to investigate how environmental and economic flows impact regional governance, focusing on efforts to manage agricultural phosphorus to achieve water quality goals. A material flow account is developed to estimate phosphorus flows embedded in …

Fragmentation, Rearrangement, And C-H Insertion: Reactions Of Vinyl Cations Derived From Diazo Carbonyls, Sarah Elizabeth Cleary

Graduate College Dissertations and Theses

Many commercialized medicinal compounds are analogs of chemicals isolated from sources found in nature (also called natural products). However, the natural sources of these chemicals, such as plants, fungi, or insects, only offer small quantities of these bioactive agents. Thus, it is typically desirable to find ways to synthesize these products and their analogs in large quantities using cost-effective methods that also minimize the impact on the environment. It is also important to develop strategies that expedite the process of modifying the natural products, which allows medicinal chemists to determine which functional groups are enhancing or deleterious to the bioactivity. …

Ecological Stormwater Management: Analysis Of Design Components To Improve Understanding And Performance Of Stormwater Retention Ponds, Rebecca Tharp

Graduate College Dissertations and Theses

Stormwater runoff from developed land is a source of pollution and excessive flow to waterways. The most commonly employed practices for flow and volume control are stormwater ponds and basins (also referred to as detention and retention ponds). These structures can be effective at controlling peak discharge to water bodies by managing flow timing but are often ineffective at removing nutrients, particularly in dissolved forms. Pond morphology coupled with place-specific characteristics (like soil type and drainage area characteristics) may influence plant community composition in these water bodies. The interaction of physical, chemical, and biological elements in stormwater ponds may affect …

The Synthesis Of Highly Substituted Aromatics And The Reaction Of Alkene Pi Systems With Vinyl Cations, Nicholas Jarrod Dodge

Graduate College Dissertations and Theses

Aldol cyclotrimerizations have been used to achieve the rational chemical synthesis of both fullerenes and fullerene fragments in the past. Under certain conditions this reaction produces the corresponding cyclotetramer which has sometimes been regarded as an undesired byproduct. This work details efforts to synthesize and use these cyclotetramers toward a synthesis of a C240 fullerene fragment. One principal focus in this work is tridecacyclene, a cyclic tetramer of acenaphthylene given its name by our group for its thirteen rings. Relatively low yields for the synthesis of tridecacyclene and its derivatives drove us to investigate the mechanism of its formation and …

Quantum Many - Body Interaction Effects In Two - Dimensional Materials, Sanghita Sengupta

Graduate College Dissertations and Theses

In this talk, I will discuss three problems related to the novel physics of two-dimensional quantum materials such as graphene, group-VI dichalcogenides family (TMDCs viz. MoS2 , WS2, MoSe2 , etc) and Silicene-Germanene class of materials.

The first problem poses a simple question - how do the quantum excitations in a graphene membrane affect adsorption? Using the tools of diagrammatic perturbation theory, I will derive the scattering rates of a neutral atom on a graphene membrane. I will show how this seemingly naive model can serve as a non-relativistic condensed matter analogue of the infamous infrared problem in Quantum Electrodynamics. …

An Autothermal, Representative Scale Test Of Compost Heat Potential Using Geostatistical Analysis, William J. Mccune-Sanders

Graduate College Dissertations and Theses

Composting has been practiced for thousands of years as a way of stabilizing and recycling organic matter into useful soil amendments. Thermophilic compost releases significant amounts of heat at temperatures (~140 °F) that are useful for environmental heating or process water. This heat has been taken advantage of in various ways throughout history, but development of a widely adopted technology remains elusive.

The biggest barrier to adoption of compost heat recovery (CHR) systems is projecting accurate, attractive economic returns. The cost of transfer equipment is significant, and with variability in composting substrates and methods, it is difficult to predict the …

Cityscape Connections: National Park Service Relevance And Resilience In Urban Areas, Elizabeth Eleanor Perry

Graduate College Dissertations and Theses

The National Park Service (NPS) strives to embody U.S. democratic ideals, conserving our collective stories and scenery for their intrinsic value and the enjoyment of current and future generations. However, although these places are conserved for all, they are not enjoyed by all. As with other conservation agencies, the NPS finds itself increasingly concerned with building relevance with diverse potential stewards. In cities, where 80% of the U.S. population and 40% of the NPS portfolio is based, there is a prime opportunity to build relevance with large, diverse, and proximate audiences. Recognizing this opportunity, the NPS initiated its Urban Agenda …

Water Quality Performance And Greenhouse Gas Flux Dynamics From Compost-Amended Bioretention Systems & Potential Trade-Offs Between Phytoremediation And Water Quality Stemming From Compost Amendments, Paliza Shrestha

Graduate College Dissertations and Theses

Stormwater runoff from existing impervious surfaces needs to be managed to protect downstream waterbodies from hydrologic and water quality impacts associated with development. As urban expansion continues at a rapid pace, increasing impervious cover, and climate change yields more frequent extreme precipitation events, increasing the need for improved stormwater management. Although green infrastructure such as bioretention has been implemented in urban areas for stormwater quality improvements and volume reductions, these systems are seldom monitored to validate their performance. Herein, we evaluate flow attenuation, stormwater quality performance, and nutrient cycling from eight roadside bioretention cells in their third and fourth years …

Exploration Of Zirconium-Catalyzed Intermolecular Hydrophosphination With Primary Phosphines: Photocatalytic Single And Double Hydrophosphination, Christine Anne Bange

Graduate College Dissertations and Theses

Catalytic hydrophosphination has enormous potential in the selective preparation of value-added organophosphines, despite the challenge of the reaction. This dissertation aims to address the hurdles in catalytic hydrophosphination with respect to substrate scope, selectivity, and reaction conditions using [қ5 –N,N,N,N,C– (Me3SiNCH2CH2)2NCH2CH2NSiMe2CH2]Zr (1).

Compound 1 readily engages with a suite of primary phosphines. These are challenging substrates for this reaction, but 1 readily provides high conversions with these substrates. Increasingly large primary phosphines, including chiral phosphines, undergo catalysis with 1. Furthermore, a variety of underreported unsaturated substrates can be functionalized in catalytic hydrophosphination with 1. Alkynes are underreported substrates, but 1 …