Physical Sciences and Mathematics Commons^™

Effects Of Urbanization On Eutrophication Parameters In Three Tidal Creeks, Ella Swantek

Honors Theses

Marshes and swashes are vital environments as a controlling barrier between land affected by various pollutants and the ocean. Eutrophication and the effects of this process can be detrimental for the areas experiencing it. I am interested in ways areas that have little contact with human interactions compare to areas that are heavily urbanized, and whether either of these locations is at a higher risk for eutrophication. Using spectrophotometry and fluorometry, I analyzed samples collected from the relatively undeveloped and restricted-access locations of Waities Island Beach and Dunn Sound monthly for dissolved nutrients, and chlorophyll. At the time of sampling, …

The Impact Of Heterogeneous Voting Strategies And Candidate Issue Adaptation On Elections: An Agent-Based Model, Harmony Peura

Student Research Submissions

Political candidates in a democracy articulate positions on the issues of the day, but they are also highly aware of voter sentiment on those issues, and tailor their campaigns accordingly as they seek to win elections. Voters, too, adjust their political opinions based on (among other things) interactions with others in their social network. I present an agent-based simulation that models this dynamic interplay between candidates and voters, in order to shed light on what outcomes candidates can expect to result from a policy of “chasing” votes. The voters in the simulation differ from one another in the decision procedure …

Techniques And Trials In Pteridophyte Conservation And Cultivation, Jessica Bartel

Senior Theses and Projects

With the progressive nature of climate change conditions globally over the past century, there has been increasing focus on conservation of all species, but particularly those already endangered. Over 12,000 species of ferns live on Earth, and they do not produce seeds, so an investigation into their spores and how they reach maturity will allow us to preserve more genetic material in the future for these species. As a result, we investigated ex situ conservation and survivability of in vitro cultured gametophytes of within the genus Dryopteridaceae through herbarium sample germination rates across samples representing a wide age range ( …

Investigating The Drought Sensitivity Of Intermontane-Basin Groundwater Systems In Western Montana Using Standardized Drought Indices, Daniel Buckley

Graduate Theses & Non-Theses

Drought is a worldwide phenomenon, and many metrics have been developed to help monitor and understand drought. In this study, the drought sensitivity of two different western Montana intermontane-basin groundwater systems were analyzed: the Bitterroot Valley and the Gallatin Valley. Different standardized meteorological drought indices, namely, the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), were compared against the Standardized Groundwater level Index (SGI) to better understand groundwater sensitivity to meteorological forcing. The SPI and SPEI were computed using precipitation and reference evapotranspiration data from the gridMET dataset. Groundwater level data from the Montana Bureau of Mines …

Characterizing The Engineering Properties Of Three Lithologies From Montana And Idaho Using Acoustic Emissions And Stress-Strain Measurements, Mary Humphreys

Graduate Theses & Non-Theses

In this study, stress and strain measurements from unconfined compression tests were used to determine the peak stress, yield stress, Young’s modulus, and Poisson’s ratio of 20 specimens representing three lithologies (sandstone, norite, and argillite-quartzite mix) from Idaho and Montana. Along with traditional strength and deformation parameters, crack initiation (CI) and crack damage (CD) values were also interpreted, corresponding to the stress levels associated with the formation and coalescence of microcracks as a specimen is exposed to increasing stress levels. Acoustic emissions (AE) data were collected along with traditional stress-strain data as this has become a popular method for interpreting …

Impacts Of Hurricane Idalia’S Surge On Coastal Sand Biogeochemistry, Wendy "Cor" Mchone

Honors Theses

Beaches are heavily influenced by extreme events, such as hurricanes. Biological and chemical processes, such as primary production and diagenesis are often interrupted by these events. To examine the effects of hurricanes on coastal biogeochemistry, this study used sand and porewater samples from Waties Island, SC, which were collected before and after Hurricane Idalia. The samples were analyzed for macronutrient concentrations, organic content, and chlorophyll concentrations. Macronutrient pore water concentration changes were not uniform. The inventory of nitrite decreased significantly after the storm, which was reflected in slight increases in the inventories of nitrate and ammonium. Concentrations of nitrate, which …

Gis Analysis Application Of Flood Risk Map In Beijing, China, Yuxuan Liu

Honors Capstones

From the end of July to the beginning of August 2023, Beijing, China, affected by Typhoon "Dusuri" experienced the most precipitation in the Beijing area in 140 years of instrument measurement records. This event led to the evacuation of more than 1.8 million people across the Beijing-Tianjin-Hebei region and the tragic loss of 62 lives. After experiencing such fierce heavy rainfall and flood disasters, how to predict and prepare for such catastrophic events and avoid losses in the future has become a crucial problem. Geographic information systems (GIS) can integrate different layers of geospatial information and provide us with powerful …

Sedimentary Conditions At A Tidal Creek That Exhibits Seasonal Pelagic-Benthic Variations, Jack B. Corbin

Honors Theses

Tidal creeks in the Grand Strand of South Carolina are small but numerous connectors between land and ocean. One of these creeks, White Point Swash, exhibits a seasonal switch between planktonic and benthic photosynthesizers. As plankton become less abundant in fall, benthic macroalgae bloom, aided by lower water levels due to fall-winter dredging of the main channel, until late Spring. This study builds on previous findings and examines sedimentary conditions at this site further. Sedimentary chlorophyll a (in microphytobenthos) and pore water nutrient concentrations are confirmed to be higher than water-column concentrations. Sedimentary nutrient fluxes to the sediment-water interface, calculated …

Boolean Group Structure In Class Groups Of Positive Definite Quadratic Forms Of Primitive Discriminant, Christopher Albert Hudert Jr.

Student Research Submissions

It is possible to completely describe the representation of any integer by binary quadratic forms of a given discriminant when the discriminant’s class group is a Boolean group (also known as an elementary abelian 2-group). For other discriminants, we can partially describe the representation using the structure of the class group. The goal of the present project is to find whether any class group with 32 elements and a primitive positive definite discriminant is a Boolean group. We find that no such class group is Boolean.

Towards A Pleasurable Food Experience: Influencing People's Liking, Taste Perceptions, And Mediated Emotions Using Augmented Flavor Experiences, Meetha Nesam James Ravindran Santhakumar

Electronic Theses and Dissertations

The multisensory nature of food and beverage flavors plays an integral role in our everyday lives. While eating is primarily for survival, individuals seek pleasure in their eating experiences through diverse means. Prior research has acknowledged that the experience of flavor is inherently multisensory, engaging the five basic senses (taste, smell, sight, touch, and hearing) and integrating additional sensory inputs(temperature, humidity, spatial smell, lighting, and even the visual and tactile characteristics of cutlery). To enhance the pleasure of consuming food and beverages, individuals consider various perceptual and cognitive factors, including the pleasure derived from taste sensations, overall hedonic liking of …

Mesopelagic Microplastic Transport Interactions With The Biological Carbon Pump, Mikayla Clark

Electronic Theses and Dissertations

Numerous studies on the transport and fate of plastic have alluded to a size-specific mechanism for removing microplastics (plastics below 5mm in diameter) from the epipelagic. Plastics like polyethylene and polypropylene which are less dense than seawater during manufacturing and use have been found throughout the water column and even in seafloor sediments. However, the mechanism for their vertical transport is poorly understood. This project calculates the vertical flux of microfibers during the 2021 EXPORTS North Atlantic campaign and captures the decline of the spring bloom from the base of the mixed layer to the mesopelagic by utilizing both lagrangian …

Human Perception Of Modern Light Field Rendered Displays: A Comparison Of A Lightfield And Headtracked Display System And Human Perception Of Animation Degradation Independent Of Render Frame Rate, Tim Bruce

Electronic Theses and Dissertations

This research directly compares natively head tracked spatial displays against actively head tracked ones. The belief is that by suppressing the latency, emulation of object presence can be improved. Modern Virtual Reality (VR) headset systems target 90Hz refresh rates in order to reduce tracking latency, yet with such low latencies, users still report motion sickness. Frame rates in film target 24-30Hz for smooth motion. This disconnect between frame rates for smooth motion and head tracking speed indicates that they may not be related. This thesis addresses these questions of latency and animation speed by building two display systems, a native …

Student Mathematical Sensemaking In The Transition From Spins To Positions In Quantum Mechanics, Anthony R. Pina

Electronic Theses and Dissertations

Quantum mechanics (QM) is a fundamental theory in physics that was developed based on a series of experiments. Rather than being built up from first principles, QM is built on a series of postulates that describe the outcomes of those experiments. The postulates establish both the mathematical formalism and basic concepts used to model quantum systems. While different systems require varying degrees of complex mathematics to model, the basic principles remain.

“Spins-first” QM instruction takes advantage of these varying degrees of mathematical difficulty by first introducing students to spin-1 2 systems which can be modeled with relatively simple mathematics. These …

Towards Scalable Autonomous Underwater Construction With Free-Floating Robots, Samuel Eric Lensgraf

Dartmouth College Ph.D Dissertations

This thesis presents the first free-floating autonomous underwater construction system. Our system built structures weighing up to 100Kg (75Kg in water). Our robot builds structures made of standard cinder blocks and custom designed interlocking cement blocks. It is the first construction robot that uses active buoyancy compensation to efficiently transport building materials. It is also the first construction robot that can reconfigure visual fiducial markers on a foundation during the construction process to expand its working area.

Underwater construction is a challenging problem for free-floating robots. Currents can buffet the robot, and visibility conditions can change. We focus on achieving …

An Alternate Proof For The Top-Heavy Conjecture On Partition Lattices Using Shellability, Brian Macdonald, Josh Hallam

Honors Thesis

A partially ordered set, or poset, is governed by an ordering that may or may not relate
any pair of objects in the set. Both the bonds of a graph and the partitions of a set are
partially ordered, and their poset structure can be depicted visually in a Hasse diagram. The
partitions of {1, 2, ..., n} form a particularly important poset known as the partition lattice
Πn. It is isomorphic to the bond lattice of the complete graph Kn, making it a special case
of the family of bond lattices.
Dowling and Wilson’s 1975 Top-Heavy Conjecture states that …

A Spatial Decision Support System For Rent Estimation Of Retail Spaces In Manhattan Using Geographically Weighted Regression And Spatial Regression, Andie M. Migden Miller

Theses and Dissertations

This report outlines an automated, three-phase Spatial Decision Support System that creates models to estimate rent of retail spaces across Manhattan. First, enrich data with predictors. Second, optimize spatially aware neighborhood-level models by combining GWR, spatial regression, and non-spatial regression. Finally, visualize results in an Esri-based WebApp.

Analysis Of Bayesian Transfer Function Fitting Method - A Potential Tool For Estimating Interferometer Uncertainty, Caden Swain

Honors Thesis

The Response Function of the LIGO Interferometer is central to reconstructing the strain produced by incoming gravitational waves. As a function of the interferometer's response to external stimuli, the Response Function is both analytically modeled and experimentally measured using excitations from the photon calibrator system at discrete frequencies. The uncertainty in each data point is propagated to the residual between the model and measurements, with both the uncertainty and residual being interpolated over a broadband frequency range. This project explores an alternative method to estimating the uncertainty and systematic error present in the Response function model through the utilization of …

High Frequency And Seasonal Controls On Calcium Carbonate Saturation States In Two Maine Estuaries, Catherine Liberti

Electronic Theses and Dissertations

The Gulf of Maine is a highly productive shelf sea in the Northwest Atlantic Ocean that supports many important commercial shellfish. The Gulf of Maine has naturally low calcium carbonate saturation states (𝛀) due to its relatively cold and fresh waters. 𝛀 has been shown to be important predictors of larval and juvenile shellfish growth and mortality. Many of these shellfish species spend all or part of their life cycle within the estuaries that fringe the Gulf of Maine and shellfish aquaculture within the estuaries is increasing rapidly. The 𝛀 of these estuaries are poorly understood, particularly on high frequency …

Local Converse Theorem For 2-Dimensional Representations Of Weil Groups, William Lp Johnson

Electronic Theses and Dissertations

A local converse theorem is a theorem which states that if two representations \chi_1, \chi_2 have equal \gamma-factors for all twists by representations \sigma coming from a certain class, then \chi_1 and \chi_2 are equivalent in some way. We provide a direct proof of a local converse theorem in two distinct settings. Previous proofs published in the literature for these settings were indirect proofs making use of various correspondences between representations of other groups. We first prove a Gauss sum local converse theorem for representations of (F_{p^2})^{\times} twisted by representations of F_p^{\times}. We then apply this theorem to tamely ramified …

Identification Of Conceptual Neighborhoods And Topological Relations In Z2, Brendan P. Hall

Electronic Theses and Dissertations

Topological relations are an essential element of spatial queries and reasoning about spatial information. The predominant model for topological relations in geographic information systems—the 9-intersection—identifies sixteen different relations between groups of pixels (called raster regions) given a set of conditions restricting the composition of the regions interior and boundary. Several of these relations are dependent on the raster region sizes to be realized. An example, ‘Completely Inside' would require raster regions to be sufficiently different in size for one raster to entirely encompass the other. By developing an iterative computational model, this work generates conceptual neighborhood graphs that outlined …

An Interdisciplinary Review: How Rapid Climate Change Is Impacting Human Health, Environmental Policy, And Voter Behavior, Douglas Hasson

Electronic Theses and Dissertations

Preface As an interdisciplinary Ph.D. student at UMaine’s Climate Change Institute, I have an obligation to review a reasonably broad set of applicable climate-related topics, while conducting unique research and tackling specific research questions, problems, and providing substantive conclusions. As such, I have engaged a case study approach where questions specific to the science, policy, and politics of climate change are addressed. Those three case studies are described in more detail below. Background and Context As of July 2023, the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) validates and expands on thousands of peer-reviewed publications and …

Mechanistic Study Of Photochemical And Advanced Oxidation Processes For Degradation Of Pharmaceuticals In Water, Melissa J. Chisholm

Electronic Theses and Dissertations

Pharmaceuticals and personal care products (PPCPs) are contaminants in water worldwide and the effects of the accumulation of these contaminants in the environment are a growing concern. Current water treatment methods involve chlorination and chloramination, which have the potential to create chlorinated by-products that are possibly more harmful than the starting material that was the target of decomposition. Alternative methods to chlorination are advanced oxidation processes (AOP). Previous studies of AOPs often focused on the rate at which the target compound is removed, but neglect to evaluate the by-products.

The compounds of interest in this study were chosen because of …

Evaluation Of Anodes And Modular Membrane-Less Single Cell Reactor Designs For On-Site Hypochlorous Acid Generation, Nelson C. Chime

Electronic Theses and Dissertations

Ensuring safe drinking water and effective sanitation remains a global priority. The shortages of disinfectants experienced during the COVID-19 pandemic further underscore the importance of reliable disinfection methods. Chlorine-based disinfection is widely used but poses safety hazards and logistical challenges in its traditional production and transportation forms. Alternately, on-site chlorine generation using electrochemical conversion of aqueous sodium chloride offers a promising solution, mitigating these risks and providing a flexible approach to disinfection. This thesis investigates the performance of various anode materials and modular, membrane-less, single-cell reactor designs to optimize on-site chlorine generation. Optimization included minimizing specific electrical consumption for chlorine …

Analytical And Numerical Analysis Of The Sirs Model, Catherine Nguyen

Student Research Submissions

Mathematical models in epidemiology describe how diseases affect and spread within a population. By understanding the trends of a disease, more effective public health policies can be made. In this paper, the Susceptible-Infected-Recovered-Susceptible (SIRS) Model was examined analytically and numerically to compare with the data for Coronavirus Disease 2019 (COVID-19). Since the SIRS model is a complex model, analytical techniques were used to solve simplified versions of the SIRS model in order to understand general trends that occur. Then by Euler's Method, the Runge-Kutta Method, and the Predictor-Corrector Method, computational approximations were obtained to solve and plot the SIRS model. …

Signal Processing Algorithms For Doppler Lidar Sensors, Samantha Grubb

Physics and Astronomy Honors Papers

Light detection and ranging (LiDAR) is a remote sensing technology that obtains relative distance and velocity measurements between a sensor and a defined target by using light transmitted and received from the target. FMCW Doppler LiDAR, a particular variant of LiDAR, functions by analyzing the frequency shift in the reflected light to determine the target's range and velocity. This technology plays a crucial role across various sectors including defense, aerospace, and automotive. This paper presents signal processing algorithms designed to optimize data obtained from Doppler LiDAR sensors. By applying various window functions to time domain data, the Signal-to-Noise Ratio (SNR) …

On Distortion Of Surface Groups In Right-Angled Artin Groups, Lucas Bridges

Mathematical Sciences Undergraduate Honors Theses

Surfaces have long been a topic of interest for scholars inside and outside of mathe- matics. In a topological sense, surfaces are spaces which appear flat on a local scale. Surfaces in this sense have a restricted set of properties, including the behavior of loops around a surface, codified in the fundamental group.

All but 3 surface groups have been shown to embed into a class of groups called right-angled Artin groups. The method through which these embeddings are created places large restrictions on all homomorphisms from surface groups to right-angled Artin groups.

One such restriction on these homomorphisms is …

Convergence Estimate Of Minimal Residual Methods And Random Sketching Of Krylov Subspace Methods, Peter Westerbaan

All Dissertations

This study concerns two main issues in numerical linear algebra: convergence estimate of minimal residual methods based on explicit construction of approximate min-max polynomials for in- definite matrices, and development and analysis of Krylov subspace methods using non-orthonormal basis vectors based on random sketching. For a matrix A with spectrum Λ(A), it is well known that the min-max polynomial problem min max |pk (z)| pk ∈Pk, pk (0)=1, z∈Λ(A) is used to bound the relative error of Krylov subspace minimum residual methods or similar methods. For a symmetric positive definite matrix A, the min-max polynomial for the Conjugate Gradient (CG) …

Models Of Functional Redundancy In Ecological Communities, Sandra Annie Tsiorintsoa

All Dissertations

Functional redundancy is the number of taxa that perform a given function within a given community. In most systems, high levels of functional redundancy are important, because they contribute to ecosystem stability. However, we currently have very little understanding of why functional redundancy varies among communities. One possible factor that could affect functional redundancy is environmental complexity. Many studies show that simplified ecosystems harbor communities with lower taxon diversity. What is less clear is if this simplicity and lower taxon diversity also affects functional redundancy. To answer this question, we use metacommunity models to explore the connection between environmental complexity …

Time Resolved X-Ray Spectroscopy Of Highly Charged Ar, Nd, And Pr, Timothy Burke

All Dissertations

Highly Charged Ions (HCIs) may be considered ideal mini-laboratory in which one can study the physics of matter and light in an environment of high internal electric field that can not be recreated with standard lab equipment. The remaining electron(s) exist in the extremely large electric field of the nucleus and therefore measurements of electronic transitions in these systems provide stringent tests of our understanding of physics in extreme conditions. Quantum electrodynamics (QED) despite being a powerful theory exhibits large discrepancies for systems under extreme conditions. The work here investigates the atomic properties within non-Maxwellian plasmas. The HCI plasmas studied …

Applications Of Conic Programming Reformulations, Sarah Kelly

All Dissertations

In general, convex programs have nicer properties than nonconvex programs. Notably, in a convex program, every locally optimal solution is also globally optimal. For this reason, there is interest in finding convex reformulations of nonconvex programs. These reformulation often come in the form of a conic program. For example, nonconvex quadratically-constrained quadratic programs (QCQPs) are often relaxed to semidefinite programs (SDPs) and then tightened with valid inequalities. This dissertation gives a few different problems of interest and shows how conic reformulations can be usefully applied.

In one chapter, we consider two variants of the trust-region subproblem. For each of these …