Theses and Dissertations at Montana State University (MSU)

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Rural school teachers' attitudes toward the use of technology in classroom assessments
(Montana State University - Bozeman, College of Education, Health & Human Development, 2024) Boateng, Samuel Kwaku Basoah; Chairperson, Graduate Committee: Gilbert Kalonde
This study explored the attitudes of rural schoolteachers toward integrating technology into classroom assessments. Despite significant investments in educational technology infrastructure, the utilization of instructional devices for assessments in rural schools remains limited. The study employed a sequential explanatory mixed methods to address five key research questions, investigating rural school teachers' attitudes towards technology-based assessments, frequencies of technology use by rural, strategies employed by rural school teachers, challenges faced by rural school teachers in tech-based assessments, and the alignment of quantitative and qualitative data. The study relied on a questionnaire and focus group interviews and opened questions for data collection from 80 teachers randomly selected from the Belgrade School District in Montana. Data were analyzed using descriptive statistics and qualitative thematic analysis. The study revealed a positive attitude among rural teachers toward technology integration in classroom assessments. Teachers were willing to use tools like Google Classroom and digital assessments, aligning with broader trends indicating a growing acceptance of technology in education. The study further indicated that teachers in rural schools employ technology regularly for various assessments, utilizing tools like Google Classroom, forms, checklists, and online quizzes. This aligns with the increasing reliance on technology for formative and summative assessments, allowing for real-time data collection and effective student performance tracking. Teachers reported diverse strategies for integrating technology, including digital assessments, online platforms, and technology tools. These approaches align with previous studies emphasizing technology's role in enhancing assessment practices, promoting student engagement, and supporting differentiated instruction. The study also found that rural teachers face challenges such as unreliable internet connectivity, outdated hardware, and insufficient training, highlighting the need for targeted interventions and support mechanisms. The study recommends four strategies to improve rural education: addressing infrastructure gaps, providing professional development for teachers, establishing collaborative networks, and collaborating with policymakers to ensure equitable access to technology resources. These measures aim to create dynamic learning environments, enhance teachers' capabilities, foster a supportive community, and bridge the rural-urban educational divide. The study concludes by highlighting actionable insights for improving technology integration in rural classrooms, emphasizing tailored professional development and flexible implementation strategies.
Effect of process variables on the uncured handleability and formability of stretch broken carbon fiber
(Montana State University - Bozeman, The Graduate School, 2022) Rezaul, Riad Morshed; Chairperson, Graduate Committee: Cecily A. Ryan
Carbon fiber is a high-performance reinforcing material used extensively in aerospace composites. Although carbon fiber is used in both continuous and discontinuous form, the continuous carbon fiber is limited by its inability to stretch due to its low strain to failure during manufacturing structures with complex geometries. Stretch broken carbon fiber (SBCF) is a type of discontinuous and aligned carbon fiber which has the potential to solve this limitation of inextensibility of its continuous counterpart. The discontinuous nature of SBCF enhances its stretchability making this material a prime candidate for manufacturing parts with complex curvatures. SBCF is generated by stretching the fibers using a pair of differentially driven rollers, which breaks the fibers at their intrinsic flaws. Although SBCF can be stretched due to being discontinuous, it compromises the tensile strength due to the lack of fiber continuity. Therefore, a polymeric coating known as sizing is applied to the SBCF to reconstruct its tensile strength. In the context of SBCF production, sizing serves two important functions. Firstly, sizing provides uncured carbon fiber the desired handleability and back-tension ability. Secondly, sizing enhances the formability of SBCF, which is a defined as the ease at which a material can be formed into a desired shape without failure. The goal of this work is to investigate the effect of process variables on the generation of stretch broken carbon fiber with consistent and repeatable material properties. The stretch broken carbon fiber research group at Montana State University (MSU) has developed a stretch breaking machine known as 'Bobcat' to generate single tow MSU SBCF. The noteworthy process variables related to MSU SBCF production includes sizing deposition on the tow, stretch ratio, nip force, line speed, fiber length distribution, and tow tenacity. Target amount of sizing deposition on MSU SBCF tow was achieved by choosing an appropriate sizing bath. A temperature-controlled tow tenacity result suggests that MSU SBCF possesses adequate handleability, back-tension ability and formability. MSU SBCF also shows a narrow fiber length distribution and relatively short mean fiber length which indicate improved formability. Reproducibility of these results were observed in the replicate batches of MSU SBCF. Suitable stretch ratio and nip force regimes were identified to optimize MSU SBCF production.
Applications and diagnostics for dimension reduction of multivariate data
(Montana State University - Bozeman, College of Letters & Science, 2022) Harmon, Paul Gary; Chairperson, Graduate Committee: Mark Greenwood; This is a manuscript style paper that includes co-authored chapters.
Working with high-dimensional data involves various statistical challenges. This dissertation overviews a suite of tools and methods for dimension reduction, using latent- variable models, techniques for mapping high-dimensional data, clustering, and working with multivariate responses across a variety of use cases. First, we propose and develop a method for classifying institutions of higher education is and compare with the current standard for university classification: the Carnegie Classification. We present a classification tool based on Structural Equation Models that better allows for modeling of correlated indices than the PCA-based methodology that underlies the Carnegie Classification. Additionally, we create a Shiny-based web application that allows for assessment of sensitivity to changes in the underlying characteristics of each institution. Second, we develop a novel methodology that extends the Cook's Distance diagnostic for identifying influential points in regression to a new application on high-dimensional mapping tools. We highlight a PERMANOVA-based method for calculating the difference in the shape of resulting ordinations based on inclusion/exclusion of points, similar in style to the influence diagnostic Cook's Distance for regression. We present a set simulation studies with several mapping techniques and highlight where the method works well (Classical Multidimensional Scaling) and where the methods appear to work less effectively (t-distributed Stochastic Neighbor Embedding). Additionally, we examine several real data sets and assess the efficacy of the diagnostic on thsoe data sets. Finally, we introduce a new method for feature selection in a specific type of divisive clustering, called monothetic clustering. Utilizing a penalized matrix decomposition to re- weight the input data to the monothetic clustering algorithm allows for reduction in noise features allows this clustering method to better make splits based on single features at a time, leading to better cluster results. We present a method for tuning both the number of clusters, K, and the degree of sparsity, s, as well as simulation studies that highlight the efficacy of noise reduction in monothetic clustering solutions.
Mary Cassatt (1844-1926): advising against convention
(Montana State University - Bozeman, College of Arts & Architecture, 2022) Hanger, Paige McCarthy; Chairperson, Graduate Committee: Melissa Ragain
American artist, Mary Cassatt became an advisor when she joined the Impressionists and by the 1890s, she as a celebrated advisor, who worked with elite Gilded Age collectors like the Havemeyer's of New York, the Palmers of Chicago, the Sears of Boston, and others. Anchored in market-based and epistolary research, this thesis will examine Cassatt's advising career and her graphic work. Cassatt taught her clients to value artworks that included both stylistic elements comfortable to American taste and unfamiliar modernist tropes. As an advisor, Cassatt educated her clients to acquire works which were hybrid in nature and borrowed stylistic qualities from accepted artwork and from modernist esthetics. The addition of these in-between works to American collections primed American taste to incrementally accept modernism, realism, and the avant-garde into Gilded Age collections. Cassatt's impact on her clients' collections shaped American collecting habits and the collections of American national museums.
Does bone-to-cartilage fluid transport exist and is it relevant to joint health?
(Montana State University - Bozeman, College of Engineering, 2024) Hislop, Brady David; Chairperson, Graduate Committee: Ronald K. June II; This is a manuscript style paper that includes co-authored chapters.
Osteoarthritis (OA) afflicts millions of people each year. The onset of OA has been associated with many factors including increased bone-cartilage fluid transport, yet a cure remains elusive. To implicate bone-cartilage fluid transport in the progression of OA, further studies are needed on fluid transport in health. Recent studies have challenged the assumption that no fluid transport occurs between bone and cartilage in healthy joints. However, many gaps remain in our understanding of bone-to-cartilage fluid transport, including 1) do fluid pressure gradients develop at the bone-cartilage interface, 2) do traumatic injuries impact subchondral bone stiffness, and synovial fluid metabolism 3) do larger molecules move from bone-to-cartilage and does cyclic loading enhance such movement, 4) what material properties influence bone-to-cartilage fluid transport 5) do distinct metabolism changes occur with osteoarthritis, evaluated using a novel clustering method. Our results showed the development of fluid pressure gradients at the osteochondral interface, and that cyclic compression enhances bone-cartilage fluid transport. Furthermore, our results showed that proteoglycan loss, and decreased subchondral bone stiffness increased bone-cartilage fluid transport. Finally, we showed that in the first week after traumatic joint injuries (e.g., ACL tears) subchondral bone volume decreases, and subchondral bone stiffness increases, while the synovial fluid metabolism shifts. In conclusion, we showed that osteochondral fluid transport is enhanced by cyclic compression for larger molecules than previously studied (3kDa dextran), and that material parameters changes associated with the progression of OA alter bone-cartilage fluid transport. These studies provide novel understanding of bone-to-cartilage fluid transport, leading us one step closer to understanding OA as a whole joint disease.
Pollinator conservation and restoration in semi-natural ecosystems
(Montana State University - Bozeman, College of Letters & Science, 2022) Glenny, William Robb; Chairperson, Graduate Committee: Laura Burkle; This is a manuscript style paper that includes co-authored chapters.
Semi-natural ecosystems are areas with biological and physical characteristics that resemble natural ecosystems but are also affected by anthropogenic disturbances. Semi-natural ecosystems are also areas with high insect pollinator diversity. Land management actions within semi-natural ecosystems may therefore be important to counteract future declines of insect pollinators. However, current restoration strategies for insect pollinator communities are based on evidence from agricultural ecosystems, which have frequent human interventions to ensure plant success, neglect the importance of nesting materials, and primarily benefit generalist species. To inform management actions for the conservation and restoration of insect pollinators in semi- natural ecosystems, I (1) synthesized the current understanding of the effects of common land management actions on insect pollinators on public lands in the US, (2) identified habitat characteristics which structure the taxonomic and functional diversity of bee communities, (3) evaluated the strength of influence of mechanisms associated with diet breadth across groups of bee species and (4) designed a conceptual model which can be used to select flowering plant species to provide food resources for bee communities in semi-natural ecosystems. Management actions that increase the abundance of floral and nesting resources to support bee species from different functional groups are required to conserve and restore insect pollinator communities in semi-natural ecosystems. I found that (1) management actions have positive, neutral, and negative effects on insect pollinators, but research trends vary depending on the taxon and habitat type, (2) the taxonomic and functional diversity of bee communities are structured by the abundance of both floral and nesting resources, (3) patterns of abundance across space and time have a more positive effect on the diet breadth of bumble bee species compared to non- bumble bee species, and (4) wildflower species that receive a high visitation rate and richness, occupy functionally important positions within bee-flower interaction networks, and are spatially and temporally widespread are important to provide bee communities with food resources in semi-natural ecosystems. These wildflower species may be particularly important to include within seed mixes to revegetate semi-natural ecosystems and provide food resources for insect pollinators.
The interaction of heavy metals with the mammalian gut microbiome
(Montana State University - Bozeman, College of Agriculture, 2022) Coe, Genevieve Lea; Chairperson, Graduate Committee: Seth Walk; This is a manuscript style paper that includes co-authored chapters.
Heavy metals are for the most part, naturally occurring elements found in the environment. Some are essential, meaning they are involved in critical biochemical pathways, in all branches of life. Other heavy metals are non-essential and disrupt metabolic functions in most organisms rendering them toxic. The following research explored the interactions of the mammalian gut microbiome with an essential heavy metal, iron, and a non-essential heavy metal, methylmercury, acquired through the diet. The overarching goal was to define and characterize the influence of gut microbial interactions with heavy metals on host health. Novel experimental designs using murine models were designed to examine 1) the consequences of low iron challenge on the murine gut microbiome and whether host iron availability was affected and 2) the potential influence of the gut microbiome in methylmercury elimination rate and demethylation in conventional, germ-free, gnotobiotic, and humanized mice. Culturing in vitro and toxicity assays, 16S sequencing, deep metagenomic sequencing of human stool, bioinformatic analysis, transcriptional analysis of iron biomarkers, quantification of iron and mercury by ICP-MS and HPLC-ICP-MS methods were performed as well as the use of mouse models to examine iron and methylmercury interactions with the gut microbiome in vivo. Our results from this project indicate that the gut microbiome is significantly affected by loss of iron from the diet, and does not fully recover post-iron repletion, while the host is relatively unaffected by low-iron challenge to the gut microbiome. Methylmercury elimination and demethylation is significantly faster and higher, respectively, in mice with a gut microbiome, providing novel evidence in support of a role for the gut microbiome in methylmercury demethylation and elimination. However, exact mechanisms of microbial interactions with methylmercury in the gut have yet to be elucidated. Our data also suggests the possibility of host-mediated mechanisms of methylmercury demethylation, by yet unknown mechanisms that warrant further exploration.
An experimental study of drying in porous media in novel 2D micromodels with dual porosity
(Montana State University - Bozeman, College of Engineering, 2024) Habib, Md Ahsan; Chairperson, Graduate Committee: Yaofa Li
Drying of porous media is pervasive in numerous natural and engineering processes, such as oil recovery, CO 2 storage, and critical zone science. Drying is essentially a multiphase flow process, where the liquid phase evaporates and is displaced/replaced by the gaseous phases, as vapor diffuses out of the porous structure. In terms of pore structure and other physical characteristics like porosity and permeability, many porous matrices exhibit multi-scale heterogeneity. For instance, in critical zone, soil is often viewed as a hierarchical organization: primary particles form aggregates, which in turn form macroaggregates, effectively leading to a dual-porosity medium. Numerous activities, including gases and water transport, are known to be controlled by the resultant multiscale flow dynamics and inter-/intra-aggregate interaction during drying. However, the fundamental physics underlying drying of porous media with dual porosity is not well understood from a fluid mechanics perspective. In this work, a novel 2D microfluidic device fabrication technique has been developed. To study the multi-phase flow of air and water, emphasizing the multi-scale interaction, pore structure, and role of film flows, three distinct types of microfluidic devices have been fabricated, which bear the innovative three-layer glass-silicon- glass architecture, providing precise structural control and excellent optical access from both top and bottom. An innovative dual-magnification imaging technique has been introduced adapted for micro-PIV and epi-fluorescent microscopy which offers insightful information about the flow dynamics at both the micro- and macro-scales concurrently. In this thesis, two distinct types of experiments are outlined, focusing on diffusion-driven drying and flow-through drying, utilizing three diverse micromodels characterized by varying porous structures and distributions. The experimental results have presented the overall drying dynamics observed in different micromodels, each featuring unique porous configurations. The impact of porous geometry and external flow conditions on drying rate and associated pore-scale physics is thoroughly examined. The findings encompass a comprehensive overview of micro-macro pore interactions, as evidenced by separated saturation distribution, displacement rates, and other pertinent flow parameters. The findings have reflected the influence of pore geometry, distribution, hydraulic connectivity, and film flow on the observed effects.
Stereoselective allylic cyclizations and rearrangements
(Montana State University - Bozeman, College of Letters & Science, 2022) Stankevich, Ksenia Sergeyevna; Chairperson, Graduate Committee: Sharon Neufeldt
Herein, we aim to explore the unique reactivity of allyl groups in two different areas: synthesis of densely functionalized five-membered ring systems and mechanistic studies of Pd- catalyzed formation of complex quaternary nitriles. The first part addresses the paucity of methods available for the formation of highly substituted five-membered rings, which are a common motif in natural compounds and pharmaceuticals. We developed a method that provides access to cyclopentenols and methylene cyclopentenols via the union of the Claisen rearrangement and Sakurai allylation. In this instance, the Claisen rearrangement allows for the stereospecific generation of the carbon framework, whereas the intramolecular Sakurai allylation provides a stereoselective cyclization reaction. For 1,2,5-trisubstituted cyclopenten-1-ols this approach has proven to be highly general and stereoselective, furnishing a library of cyclized products in good and very good yields and >20:1 diastereomeric ratio. For 1,2,5-trisubstituted 3- methylene cyclopentan-1-ols, we have developed a stereodivergent method whereby the one-pot stepwise Claisen-Sakurai reaction provided anti-, anti- product and the cascade Claisen-Sakurai reaction furnished syn-, anti- product as a major diastereomer with good yield. In both cases reaction mechanism was investigated to uncover the origin of diastereoselectivity using density functional theory. The second part of this research covers investigating the mechanism of a Pd- catalyzed double rearrangement to form quaternary nitriles, which are molecules of synthetic interest. We studied the mechanism of recently developed highly complex auto-tandem catalytic double allylic rearrangement of N-alloc-N-allyl ynamides to complex quaternary nitriles using density functional theory. This reaction proceeds through two separate and distinct catalytic cycles with both decarboxylative Pd-pi-allyl and Pd(0)-promoted aza-Claisen rearrangements occurring. We discovered previously unreported concomitant decarboxylation/C-C bond formation, reversible C-N ionization and a Pd(0) catalyzed [3,3]-rearrangement along with its stepwise variant. These catalytic cycles are characterized by the highly dynamic nature of the catalyst systems with large degrees of conformational flexibility and a flat potential energy surface. Our studies have rationalized the reactivity observed and can be further developed into predictive models for ligand and catalyst screening.
An exploration of whole-genome comparative genomic strategies for polyploid crop genomes
(Montana State University - Bozeman, The Graduate School, 2022) Reynolds, Gillian Lucy; Co-chairs, Graduate Committee: Brendan Mumey and Jennifer A. Lachowiec
Genome comparison for large and complex polyploid crop genomes is a highly complex venture, yet it is critical. Given a rising demand for food coupled with yield-impacting resource limitations and rapidly changing global climates it has never been more important to characterise the underlying genetic variation which underpins traits of agronomic interest. In this work, the problem of polyploidy genome comparison is explored at three levels. The first chapter characterizes the sequence relationships that exist between, and within, polyploidy genomes. This is achieved by hijacking a metagenomic strategy for rapid, and efficient, genome sequence classification. The second chapter then utilizes the identified subgenome- specific k-mer profiles for recruitment of assembled contigs and scaffolds previously only recruitable via more resource intensive optical mapping strategies. This makes a greater proportion of the assembled data usable for downstream variant analysis. The third chapter then zooms into the problem of how to identify variants from large -scale sequencing data while minimizing bias and computational costs. A critical assessment of modern variant calling for crop genomes is performed and an algorithm to further extend a new, resource efficient, approach for large scale comparative genomics is presented and critically evaluated. In all, the work presented herein takes a top-down journey from genome- and subgenome- level comparative genomics all the way to identifying base-pair resolution strategies that are capable of revealing the underlying sequences responsible for keeping the world fed.
Sleep and savoring: the influence of sleep restriction on positive emotion regulation
(Montana State University - Bozeman, College of Letters & Science, 2022) Powell, Suzanna Lee; Chairperson, Graduate Committee: Cara A. Palmer
Although previous research broadly demonstrates that sleep loss leads to reductions in positive affect, relatively few studies examine the impact of sleep loss on low and high arousal positive affective processes, the regulation of positive emotions, or the influence of different sleep stages. The current study sought to build on previous findings that suggest slow wave and rapid eye movement stages of sleep may have distinct influences on affect by examining the effects of sleep restriction on positive affect, reactivity, and regulation (i.e., savoring and dampening). Thirty-four participants (50% female, ages 18-25 years) were included in final analyses. Participants completed a healthy night of sleep (9h time in bed) and a night of sleep restriction (4h time in bed). Sleep was restricted between participants in two ways, early in the night to primarily restrict slow wave sleep and later in the night to primarily restrict rapid eye movement sleep. Following both a night of normal sleep and the night of sleep restriction, participants completed questionnaires to measure positive affect, and a video task which instructed them react normally or to savor while watching positive affect-inducing videos. After each video, participants reported on their feelings of valence, arousal, and high and low arousal positive affect. Savoring and dampening strategies utilized during the task were also reported. Following sleep restriction participants reported diminished high and low arousal positive affect compared to when they were well-rested. Participants also reported less positive reactivity to the videos when they were sleep restricted compared to when they were well-rested after both reacting normally and after savoring. However, participants experienced greater increases in positive affect when savoring compared to when they were instructed to react after sleep restriction. Slow wave sleep loss was related to marginally reduced positive affect compared to loss of rapid eye movement sleep, but no other effects of type of sleep restriction emerged. This study indicates that sleep loss results in diminished high and low arousal positive affect and blunted reactivity to positive stimuli, but that engaging in intentional up-regulation strategies may help buffer the negative effects of sleep loss.
Biocorrosion of copper by Oleidesulfovibrio alaskensis G20 biofilms in static and dynamic environments
(Montana State University - Bozeman, College of Engineering, 2024) Keskin, Yagmur; Chairperson, Graduate Committee: Brent M. Peyton; Matthew Fields (co-chair); This is a manuscript style paper that includes co-authored chapters.
This study presents a detailed examination of the intricate relationships between Oleidesulfovibrio alaskensis G20 and copper (101), emphasizing three interconnected perspectives: the kinetics of copper toxicity in three distinct media, the impact of surface finishing on microbiologically influenced corrosion (MIC), and the interaction of G20 biofilms and copper in CDC biofilm reactors. Initially, the study concentrates on the kinetic effects of copper toxicity on the growth of G20. The research meticulously quantifies the detrimental impact of different copper (II) concentrations (6, 12, 16, and 24 micron) on bacterial growth kinetics in three media: LS4D balanced (BAL), electron acceptor-limited (EAL), and electron donor-limited (EDL). Using a non-competitive inhibition model, I50 (concentrations of copper causing 50% inhibition of bacterial growth) values were calculated to be 13.1, 13.87, and 11.31 micron for LS4D BAL, EAL, and EDL media, respectively. The second part of the study shifts its focus to the effect of surface finishing on MIC of copper 101 by G20. The biofilm and corrosion pit depths were measured through a series of sophisticated analyses employing 3D optical profilometry, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX), and X-ray Diffraction Analysis (XRD). The research investigates how different levels of surface roughness, applied through metallographic grinding and polishing, influence corrosion. The findings demonstrate a clear pattern of both uniform and pitting corrosion across all surface finishes. Notably, a statistically significant decrease in corrosion rates was observed when the surface roughness of copper was altered from approximately 13?m to about 0.06?m. Finally, the study explores the interaction between G20 biofilms and copper (101) into CDC reactors to understand biofilm development on copper surfaces and its subsequent impact on copper corrosion in a dynamic environment over periods of 7, 9, and 14 days. The results showed robust biofilm formation through hexose and protein analyses and SEM images displaying progressive increases in SRB cell accumulation over time. Localized pit depths were measured and compared to static conditions, and pits showed only a 20% increase in a dynamic environment. These findings offer an improved understanding of the complex interactions between G20 and MIC of copper.
Enhancing students' engineering identities and attitudes towards engineering and technology through place-conscious engineering activities
(Montana State University - Bozeman, College of Education, Health & Human Development, 2024) Moonga, Miracle; Chairperson, Graduate Committee: Rebekah Hammack; Nick Lux (co-chair)
Students' engineering identities and attitudes toward engineering are important because they can determine if students will pursue engineering careers. However, a dearth of research focuses on how participating in place-conscious engineering affects students' engineering identities and attitudes towards engineering and technology. This explanatory sequential mixed methods study investigated the effect of engaging elementary students in place-conscious engineering activities on their engineering identities and attitudes towards engineering and technology. Students completed two place-conscious engineering activities: (1) following a local wildfire, students designed and built air filters to prevent smoke from entering the homes of affected families residing in a nearby community, and (2) after the state issued several warnings about eminent floods due to ice-jams on a local river, students designed flood prevention strategies. Quantitative data about students' engineering identities were collected using pre and post surveys of the two subscales of the Engineering Identity Development Scale (EIDS): (1) academic subscale and (2) engineering career subscale. Quantitative data regarding students' attitudes toward engineering and technology were collected using pre and post surveys of the engineering and technology subscale of the Students' Attitudes Toward Science, Technology, Engineering, and Mathematics (S-STEM). Finally, to explain the trends observed in the quantitative data, qualitative data were collected through semi-structured focus group interviews. Findings suggested that students' academic identities and attitudes towards engineering and technology improved as a result of participating in place-conscious engineering activities. The study recommends exposing elementary students to place-conscious engineering activities to improve their engineering identities and attitudes towards engineering and technology.
Underwater acoustic propagation modeling and utilization for marine hydrokinetic devices
(Montana State University - Bozeman, College of Engineering, 2024) Hafla, Erin Christine; Chairperson, Graduate Committee: Erick Johnson
Over the last two decades, there has been growing concern surrounding the increase in underwater anthropogenic sounds as expanding human populations interact with marine life and look for alternative energy production methods. That concern has led to a significant push worldwide to understand how propagated sound interacts with the surrounding marine environment. Marine hydrokinetic (MHK) devices are an alternative source of renewable energy available, which generate electricity from the motion of tidal and ocean currents, as well as ocean waves. Sounds produced by MHKs tend to overlap the frequency range common to both marine fauna communication and behavior. Preliminary measurements indicate that sound level values fall near the total sound decibel limitations presented by regulatory bodies. To date, the power optimization of MHK arrays has been prioritized over how its sound is produced, directed, and may impact the marine soundscape. There is a gap in knowledge regarding how marine fauna may respond to these sounds and what their physical and behavioral impact may be, and an absence in measured levels from insitu MHK deployments. A model for predicting the propagation of sound from an array of MHK sources in a real environment is essential for understanding potential impacts on a surrounding system. This work presents a fully three-dimensional solution to a set of coupled, linearized velocity-pressure equations in the time-domain as applied to underwater systems, and is an alternative sound propagation model to the Helmholtz and wave equation methods. The model is validated for a single source located within a series of increasingly complex two-dimensional and three-dimensional shallow water environments and compared against analytical solutions, examples from literature, and recorded sound pressure levels collected from Sequim Bay, WA. An uncertainty analysis for an array of MHK devices is presented to further understand how multiple turbine signals interact with one another in increasingly complex systems. This research presents a novel use of the velocity-pressure equations to analyze the variability associated with sound sources as sound propagates through a selected environment to inform the design and deployment of a MHK device or array of devices to minimize potential future impacts.
Tracing interactions of hydrogeology and land use in two Montana watersheds
(Montana State University - Bozeman, College of Agriculture, 2024) Keeshin, Skye Ilan; Chairperson, Graduate Committee: Stephanie A. Ewing
Hydrogeologic systems dictate the introduction, transport, processing, and mixing of groundwaters, with implications for both groundwater and surface water quality. Land use can transform hydrogeologic processes and water quality through contributions of human amendments, alteration of soil and aquifer materials, and redistribution and consumption of water resources. Groundwater transit times are also orders of magnitude longer than those of surface water systems, resulting in lag times in water quality changes. In this thesis, I examine water quality consequences of land use in Montana at two headwater sites using geochemical tracers in groundwater and surface water. The first is within the Powder River Basin, the largest coal producing region in the US, where manmade aquifers composed of spoils from mine overburden replace existing unconsolidated and bedrock aquifers with salinity effects on downgradient waters. In a reclaimed coulee supplying groundwater to Rosebud Creek, a tributary of the Yellowstone River, geochemical and isotopic tracers reveal lateral contributions that contribute to dilution of high salinity mine-derived waters. These contributions include local inputs from shallow unconsolidated and bedrock aquifers and inputs of water on the order of 10,000 years from regional bedrock systems. The second site is the Gallatin Valley, a rapidly urbanizing intermountain basin in the Upper Missouri headwaters, where groundwater and surface water transects reveal mixing of water with a range of ages from a few years to 100,000 years. While not associated with spatial variation in nitrate concentration, these contributions likely attenuate rising nitrate concentrations in the valley aquifer as a whole over time, reflecting spatially variable loading from a legacy of agricultural fertilization and increasingly prevalent septic wastewater systems. A large component of the Gallatin Valley aquifer is decades old water sourced from higher elevation precipitation, consistent with long travelled mountain front stream losses. This component may diminish over time with an increasingly limited snowpack. Overall, hydrogeologic systems in these two land use regimes limit but do not eliminate effects of human-derived water quality concerns, and documenting them will improve water quality forecasting with impending changes in snowpack and precipitation.
Investigations into the West Indian Chelonarium (Coleoptera: Chelonariidae) and the Antherophagus (Coleoptera: Cyptophagidae) of Montana
(Montana State University - Bozeman, College of Agriculture, 2022) Kole, John Paul; Chairperson, Graduate Committee: Michael A. Ivie; This is a manuscript style paper that includes co-authored chapters.
The discovery of a new species of Chelonarium in southern Florida, combined with the expected publication of the next edition of American Beetles requires has made it necessary to revise the West Indian Chelonariidae. Material from the West Indies was examined, names were associated with species, and species level groups were determined. Sixteen species are recognized with species definitions, descriptions, distributions, and illustrations provided. A key to the species is included. Seven species are redescribed: Chelonarium beauvoisi Latreille, 1807, Chelonarium convexum Mequignon, Chelonarium problematicum Mequignon, Chelonarium cupreum Mequignon, Chelonarium lecontei Thomson, Chelonarium maculatum Mequignon, and Chelonarium pilosellum Chevrolat. A neotype is designated for Chelonarium convexum Mequignon. Chelonarium costattipenne Mequignon, new synonymy, and Chelonarium sublavae Mequignon, new synonymy, are placed as junior synonyms of Chelonarium problematicum Mequignon. Eight species are described as new: Chelonarium auricomus Kole and Ivie, new species, Chelonarium calcarium Kole and Ivie, new species, Chelonarium floccum Kole and Ivie, new species, Chelonarium grenadensis Kole and Ivie, new species, Chelonarium latosetum Kole and Ivie, new species, Chelonarium lucidum Kole and Ivie, new species, Chelonarium nitidellum Kole and Ivie, new species, and Chelonarium sabensis Kole and Ivie, new species. Chelonarium auricomus is the second US mainland species and is apparently introduced from the Martinique and/or St. Lucia. Chelonarium punctatum Fabricius, 1801 and Chelonarium atrum Fabricius, 1801 are removed from the West Indian Fauna because of newly clarified type localities, corrected to Essequibo, British Guyana. A discussion of biogeography is provided. The Chelonariidae of the West Indies are far more diverse than was previously known, however more data is required to better determine the diversity of this group in the West Indies. Little is known of the beetles which live in the nests of wild bees. One such genus, Antherophagus, which lives in the nests of Bombus, was almost entirely unknown from Montana. Material from the MTEC was examined and species were identified using preexisting keys. A key is provided for all five North American Antherophagus, new county and state records are reported, and biology is discussed. The Antherophagus are likely more widely distributed than is currently reported.
An interpreter's guide to filmmaking
(Montana State University - Bozeman, College of Arts & Architecture, 2022) Andrus, Olivia Fay; Chairperson, Graduate Committee: Dennis Aig
Politically divisive topics like climate change are notoriously difficult to effectively communicate to the public. Using a different communication approach called interpretation within the filmmaking process, we can bridge the gap current climate change films have today with their audience. Interpretation means "a mission-based communication process that forges emotional and intellectual connections between the interests of the audience and the meanings inherent in the resource," according to the National Association of Interpretation (What is interpretation?). In this paper I will analyze the history behind interpretation and the methodology in implementing this communication style within films. Through the works of various filmmakers such as, My Octopus Teacher (2020), Ice on Fire (2019), and Ocean Souls (2020), my own experience creating an interpretive short film, The Dolphin Dilemma, this paper will discuss how specific interpretive communication methods can take politically divisive subjects, like climate change and more effectively communicate science within documentaries.
The positive emotion regulation questionnaire and the assessment of strategy use profiles as predictors of mental health outcomes
(Montana State University - Bozeman, College of Letters & Science, 2022) McCullen, Jennifer Renee; Chairperson, Graduate Committee: Brandon Scott
Past research has shown that experiencing and upregulating positive emotions may be beneficial for youths' well-being (Martin-Krumm, 2018; Young et al., 2019). Further, research with negative ER suggests having a wider range of strategies enhances ER success (Lougheed & Hollenstein, 2012). However, most studies on positive emotion regulation (ER) have focused on savoring strategies and lack youth involvement. I propose that it is not only how many strategies youth use but the pattern of strategies youth use to regulate positive emotions that relate to internalizing problems. The purpose of our study was to examine the factor structure of a novel self-report measure of positive ER strategies in adolescents and their relations to mental health as well as to investigate the number and type of profiles that emerge from youths' use of 13 positive ER strategies and differences in mental health. I recruited a sample of 349 English-speaking 13- 17-year-old youth (50% females; 32% non-binary/other gender; Mage = 15.7) who reported on positive ER strategies, anxiety, depression, difficulties regulating positive emotions, resilience, and trauma. Exploratory factor analysis of the measure indicated 10 factors. Correlations showed greater use of Self-Improvement, Physical Activity, and Positive Thinking were related to more resilience; greater use of Fantasizing and Sensation Seeking were related to more anxiety; and greater use of Sensation Seeking and Relaxation were related to more depression. Conversely, greater use of Sensation Seeking was related to less resilience; greater use of Positive Thinking was related to less anxiety; and greater use of Positive Thinking and Physical activity were related to less depression. Profile analysis revealed a 6-profile model with two unique profiles characterized by either mainly using personal growth strategies more frequently than other strategies (profile 3) or using more frequently sensation seeking and fantasizing as opposed to other strategies available to them (profile 4). ANOVA results revealed significant differences in depression among profiles. These findings demonstrate adolescents utilize a wide range of emotion regulation strategies to maintain and upregulate positive emotions. Further, certain positive ER profiles may indicate protective (high personal growth only) or risk (high sensation seeking and fantasizing) for experiencing depressive symptoms.
Comparing juvenile physiology and morphology of two high-elevation pines, Pinus albicaulis and Pinus balfouriana
(Montana State University - Bozeman, College of Letters & Science, 2023) Sparks, Katherine Elizabeth; Chairperson, Graduate Committee: Danielle Ulrich
Whitebark pine (Pinus albicaulis, PIAL) and foxtail pine (P. balfouriana, PIBA) are slow-growing, high-elevation, five needled ("high five") white pines and are foundation and keystone species in alpine and subalpine environments, providing essential resources and habitat for many species including the Clark's nutcracker and grizzly bears. In recent years, PIAL has experienced significant decline due to an amalgamation of climate change, white pine blister rust, and mountain pine beetle. As a result, PIAL is listed as endangered under the Canadian Species at Risk Act and threatened under the United States Endangered Species Act. Conversely, PIBA has experienced minimal decline. PIBA also exists in two disjunct populations, one in southern California (PIBAS) and one in northern California (PIBA N), resulting in the species being split into two sub-species (P. balfouriana subsp. austrina and balfouriana). Our study compared the physiology and morphology of the two species (PIAL and PIBA) and the two foxtail populations (PIBA N and PIBAS) to better understand how they interact with and respond to abiotic and biotic stressors in their high-elevation environments. We grew four-year-old PIAL and PIBA juveniles in a common greenhouse environment. In total, we measured 159 traits describing their morphology, biomass, stomata, xylem, budburst phenology, physiology, whole plant Volatile Organic Compounds (wpVOCs), phloem volatile resin (PVR) compounds, and Non-Structural Carbohydrates (NSCs). We found that PIAL and PIBA displayed different suites of traits that enable them to persist in their high elevation habitats, characterized by similar abiotic stressors (cold temperatures, high winds, summer drought) and biotic stressors (white pine blister rust, bark beetle). The two foxtail populations were similar for most traits except for wpVOC concentration and composition where PIBAS had significantly higher wpVOC concentration than PIBA N. For most traits, PIAL was most similar to PIBA N and differed the most with PIBAS while PIBA N was the intermediate being more similar to both groups, especially in wpVOC composition and concentration.
Thermalization and exciton localization in 2D semiconductors
(Montana State University - Bozeman, College of Letters & Science, 2023) Strasbourg, Matthew Christopher; Chairperson, Graduate Committee: Nick Borys; This is a manuscript style paper that includes co-authored chapters.
2D semiconductors are a promising class of materials to investigate for applications in the next generation of photonic devices. They can be used to generate quantum light and also exhibit correlated many-body phenomena. Many of the novel optoelectronic properties of 2D semiconductors are associated with strongly-bound hydrogen-like states known as excitons. Excitons in 2D semiconductors have binding energies on the order of 100s of meV and are stable at room temperature. At low temperatures, higher-order excitonic states such as charged excitons and biexcitons--multiple-bound excitons that are like hydrogen molecules-- and localized excitons that emit quantum light are also observed. Whether excited optically or electronically, a diversity of high-energy excitons and free carriers are produced directly after excitation. The relaxation and thermalization of these initial states influence the formation of excitons, biexcitons, and localized excitons. Here, I present work that (i) investigates the thermalization of excited states in a prototypical 2D semiconductor, monolayer (1L-) WSe2, and reports the discovery that the generation of charged biexcitons is enhanced with increasing photoexcitation energy, (ii) shows the emergence of quantum emitters (QEs) in a new 2D QE platform: 1L-WSe2 nanowrinkle arrays induced by Au nano stressors, and (iii) uses a novel method to classify the excited-state dynamics of 2D QEs and differentiate emitter populations. A suite of low-temperature energy- and time- resolved optical spectroscopies are used to conduct this work. This work shows how excited state thermalization affects the formation of exciton and biexcitons and investigates the optical properties of an emergent class of 2D quantum light emitters.

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