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Title: DEVELOPMENTAL RESPONSES TO POLYCOMB COMPLEX MUTATIONS AND PLANTING DENSITY IN HEXAPLOID WHEAT
Creator: Lopez, Selena
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Hexaploid wheat (Triticum aestivum) has undergone two hybridization events resulting in severe genetic bottlenecks, particularly in the D genome contributed by the diploid progenitor species, Aegilops tauschii. One method to regain this genetic diversity is through interspecific hybrids with diploid progenitors. This requires embryo rescues to recover progeny due to endosperm failure of the hybrids. Previous studies in Arabidopsis and rice have demonstrated that mutations in imprinted...
Show moreHexaploid wheat (Triticum aestivum) has undergone two hybridization events resulting in severe genetic bottlenecks, particularly in the D genome contributed by the diploid progenitor species, Aegilops tauschii. One method to regain this genetic diversity is through interspecific hybrids with diploid progenitors. This requires embryo rescues to recover progeny due to endosperm failure of the hybrids. Previous studies in Arabidopsis and rice have demonstrated that mutations in imprinted Polycomb Repressive Complex 2 (PRC2) genes medea (MEA), fertilization independent endosperm (FIE), and fertilization independent seed 2 (FIS2) can, or potentially can, restore endosperm function to interploidy hybrids. Homologs of MEA, FIE, and FIS2 were identified in the wheat A, B and D genomes. Pyramids of double and triple mutants were developed using a combination of Kompetative allele specific PCR (KASP) markers and amplicon sequencing. Single, double, and triple mutants at MEA, FIE, and FIS2 associated with the three subgenomes were hybridized with Ae. tauschii to identify mutant combinations that may restore endosperm function.The wheat breeding program at Michigan State University utilizes a modified bulk breeding method to rapidly advance populations from the F2 to F4 stage under greenhouse conditions. To determine the influence of planting density on yield components and plant architecture in greenhouse settings, two experiments were carried out using two spring and winter wheat. Experiments with both spring and winter wheat demonstrated that increased planting density reduces plant height, spikelets per spike, grain length and grain width.
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Title: IMPROVING GAS BARRIER PROPERTIES OF SUGARCANE-BASED LLDPE WITH CELLULOSE NANOCRYSTALS
Creator: Natarajan, Madhumitha
Date: 2021
Collection: Electronic Theses & Dissertations
Description: This study was aimed at improving the gas barrier property of sugarcane-based LLDPE using cellulose nanocrystals (CNCs). Specifically, this study evaluated the effect of testing methods (isostatic versus gravimetric) on CO2 permeability coefficient (PCO2) and/or O2 permeability coefficient (PO2) of various bio-PE grades with different densities (LLDPE, LDPE, and HDPE) as well as the effect of CNC content on crystallinity, tortuosity factor, and gas barrier properties of bio-LLDPE sheets and...
Show moreThis study was aimed at improving the gas barrier property of sugarcane-based LLDPE using cellulose nanocrystals (CNCs). Specifically, this study evaluated the effect of testing methods (isostatic versus gravimetric) on CO2 permeability coefficient (PCO2) and/or O2 permeability coefficient (PO2) of various bio-PE grades with different densities (LLDPE, LDPE, and HDPE) as well as the effect of CNC content on crystallinity, tortuosity factor, and gas barrier properties of bio-LLDPE sheets and films. The isostatic and gravimetric methods yielded similar PCO2, irrespective of PE grade. However, the PCO2 negatively correlated with PE density. All nanocomposites showed considerable improvement in gas barrier irrespective of the CNC content. The PCO2 of LLDPE sheets decreased by 36% by adding 10 wt.% of CNCs into the sheet. Similarly, a significant decline in both PO2 (about 50%) and PCO2 (about 33%) of LLDPE films was obtained by adding 2.5 wt.% of CNCs into the films. Nevertheless, no correlation was established between gas permeability and percent crystallinity of LLDPE sheet since the PCO2 decreased almost linearly with increasing CNC content whereas the percent crystallinity of LLDPE increased only up to 2.5% CNC content and remained constant thereafter. In contrast, the tortuosity factors calculated from the diffusion coefficients increased almost linearly with CNC contents and correlated well with the gas permeability improvement in the bio-LLDPE-based nanocomposites. Consequently, the enhanced gas barrier in the nanocomposite was assigned to the tortuosity effect created by the impermeable cellulose nanocrystals rather than the changes in percent crystallinity.
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Title: ASSESSING THE USE OF GOAL SETTING AND FEEDBACK TO INCREASE PHYSICAL ACTIVITY IN ADULTS
Creator: Moorehouse, Amelia Grace
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Previous research has demonstrated the efficacy of goal setting and feedback for increasing physical activity in a variety of populations. Increased physical activity is associated with health benefits such as weight management, improved muscle strength, cardiovascular health, and longevity. The present study aimed to replicate previous goal setting and feedback research to increase the weekly walking or running distance for six adults. This study also assessed the efficacy of the...
Show morePrevious research has demonstrated the efficacy of goal setting and feedback for increasing physical activity in a variety of populations. Increased physical activity is associated with health benefits such as weight management, improved muscle strength, cardiovascular health, and longevity. The present study aimed to replicate previous goal setting and feedback research to increase the weekly walking or running distance for six adults. This study also assessed the efficacy of the intervention for promoting maintenance of physical activity in a 3-month follow- up assessment. The participants in this study were six healthy adults recruited from a Midwest university and expressed interest in increasing their overall activity levels during the COVID-19 pandemic. The study utilized a multiple baseline across participants design and revealed that all participants increased their mean weekly distance in the intervention phase following baseline. Furthermore, one participant maintained an increased weekly distance following the conclusion of the intervention. Implications and suggestions for future research are addressed.
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Title: THE USE OF EQUIVALENCE-BASED INSTRUCTION TO TEACH GRADUATE STUDENTS BEHAVIOR ANALYTIC TERMINOLOGY
Creator: Hemwall, Suzanne
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Individuals pursuing their Board Certified Behavior Analyst® (BCBA®) certification are expected to have an understanding of behavior analytic terminology. In the past 10 years, demand for BCBAs® has grown significantly (Deochand & Fuqua, 2016; Behavior Analyst Certification Board, 2021). One way to teach individuals terminology is via equivalence-based instruction (EBI) and Match-to-Sample (MTS). The present study examined the use of EBI to teach six graduate students behavior analytic...
Show moreIndividuals pursuing their Board Certified Behavior Analyst® (BCBA®) certification are expected to have an understanding of behavior analytic terminology. In the past 10 years, demand for BCBAs® has grown significantly (Deochand & Fuqua, 2016; Behavior Analyst Certification Board, 2021). One way to teach individuals terminology is via equivalence-based instruction (EBI) and Match-to-Sample (MTS). The present study examined the use of EBI to teach six graduate students behavior analytic terminology. Using a multiple probe across behaviors design replicated across participants, participants were taught 30 different behavior analytic terms, definitions, and examples via a MTS teaching procedure. Participants were then assessed on their performance of untaught relations in a MTS, or selection-based, format as well as a written intraverbal format. While emergent intraverbal responding was limited, all participants demonstrated emergent selection-based responding. The results of this study can inform instructors preparing individuals seeking their BCBA® certification. Keywords: Equivalence-based instruction, Match-to-Sample, conditional discrimination, selection-based responding, topography-based responding
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Title: EVOLUTION OF AEC PROJECT NETWORKS : AN AGENT-BASED MODELING APPROACH
Creator: Pidiha, Nishchay
Date: 2021
Collection: Electronic Theses & Dissertations
Description: In Architecture, Engineering, and Construction (AEC) industry, projects call for collaboration between different expertise areas. To improve collaboration and knowledge transfer between different stakeholders, an in-depth understanding of the communication network structure is crucial. While Social Network Analysis (SNA) shows promise in analyzing communication network structures, the AEC literature to date shows its use mainly in a cross-sectional manner. A recent longitudinal case study...
Show moreIn Architecture, Engineering, and Construction (AEC) industry, projects call for collaboration between different expertise areas. To improve collaboration and knowledge transfer between different stakeholders, an in-depth understanding of the communication network structure is crucial. While Social Network Analysis (SNA) shows promise in analyzing communication network structures, the AEC literature to date shows its use mainly in a cross-sectional manner. A recent longitudinal case study shows that these networks are not static and can evolve overtime. However, due to fast-paced delivery of any AEC project, researchers often arrive at missing data, sometimes depriving them from concluding statistically significant results in a longitudinal study. Hence, there is a need for further investigating the evolution of AEC project teams network structures through a simulation that emulate certain aspects of a social network structure evolution over time.In response to this need, the study aims to explicate, how real-world size AEC project networks evolve over project delivery based on similarity of node characteristics (e.g., homophily) and node behaviors in networks (e.g., node’s popularity). To do so, the study adopted selection model, and simulated multiple agent-based models basing its initial condition on an empirical case study. The evolutions of the network structures were analyzed overtime. Finally, the study compared the results with recent similar works. Deliverables include an improved understanding of AEC project network structures and characteristics, and practical implications relating to team collaboration and coordination considering project characteristics such as team size, and complexity.
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Title: EFFECTS OF PRESENTATIONS OF ASSESSMENT ROUNDS ON PREFERENCE STABILITY
Creator: Thomas, Alexandria
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Behavior interventions have been found to be the most effective treatments for behaviors associated with Autism Spectrum Disorder (ASD). Children diagnosed with ASD tend to experience barriers in terms of communication, thus communicating wants and needs during treatment may be difficult. As a result, clinicians have used preference assessments to identify potentially reinforcing stimuli to use during behavior interventions to increase the likelihood of desired behaviors occurring again in...
Show moreBehavior interventions have been found to be the most effective treatments for behaviors associated with Autism Spectrum Disorder (ASD). Children diagnosed with ASD tend to experience barriers in terms of communication, thus communicating wants and needs during treatment may be difficult. As a result, clinicians have used preference assessments to identify potentially reinforcing stimuli to use during behavior interventions to increase the likelihood of desired behaviors occurring again in the future. Previous research on preference assessments has looked at evaluating brief preference assessments and stability of responding across time and assessments. The purpose of this study is to evaluate the extent to which responding is stable across rounds within a single MSWO for children aged 3-5 with a diagnosis of ASD. Results showed that overall; stability in responding across rounds of a single MSWO varied across participants regardless the type of stimuli used during the assessment (all edible or all tangible stimuli).Keywords: autism, preference assessments, stability
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Title: AVEC LE WALLON ON NE VA PAS LOIN : FACTEURS QUI ONT CONDUIT AU REMPLACEMENT DU WALLON PAR LE FRANÇAIS EN WALLONIE TELS QU’ILS SONT REPRESENTES DANS DEUX ROMANS D’AUTEURS WALLONS
Creator: Speers, Patricia Alberte
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Le passage au français comme langue maternelle en Wallonie (partie sud de la Belgique) est, comme dans les provinces françaises, l’aboutissement d’une situation que l’on peut qualifier de ‘diglossie’ ou ‘triglossie’ si l’on tient compte du latin utilisé par l’église catholique. L’adoption du français par l’ensemble de la population wallonne est le plus souvent considéré comme un fait accompli, et peu d’études existent sur le sujet. Ce mémoire étudie la fin de la période diglossique telle qu...
Show moreLe passage au français comme langue maternelle en Wallonie (partie sud de la Belgique) est, comme dans les provinces françaises, l’aboutissement d’une situation que l’on peut qualifier de ‘diglossie’ ou ‘triglossie’ si l’on tient compte du latin utilisé par l’église catholique. L’adoption du français par l’ensemble de la population wallonne est le plus souvent considéré comme un fait accompli, et peu d’études existent sur le sujet. Ce mémoire étudie la fin de la période diglossique telle qu’elle est représentée dans deux romans d’écrivains wallons, L’œil de la mouche d’André-Joseph Dubois et La malédiction de l’abbé Choiron d’Armel Job. L’approche utilisée est une approche sociolinguistique inspirée par celle de Robert Lafont dans son article « Un problème de culpabilité sociologique : la diglossie franco-occitane ». La période généralement acceptée comme celle à partir de laquelle le wallon cesse de se transmettre comme langue maternelle est celle des années 50. L’histoire des deux romans se passent en tout ou en partie dans les années 50. Ces romans, en peignant le tableau de différents segments de la population wallonne, nous permettent d’étudier les facteurs qui conduiront au remplacement du wallon par le français comme langue de communication en Wallonie.
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Title: MRGPRX2 MEDIATED MAST CELL RESPONSES ARE SUPPRESSED BY LACTIC ACID
Creator: Syed, Meesum H.
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Mas-related G-protein coupled receptor X2 (MRGPRX2) is a G-protein coupled receptor (GPCR) expressed in human mast cells that plays an important role in facilitating pseudo-allergic reactions as well exacerbating inflammation during asthmatic and other allergic diseases. Lactic acid, a byproduct of anaerobic glycolysis, is abundantly present in inflamed tissues and has been shown to regulate functions of several immune cells. Because the endogenous ligands for MRGPRX2 (substance P and LL-37)...
Show moreMas-related G-protein coupled receptor X2 (MRGPRX2) is a G-protein coupled receptor (GPCR) expressed in human mast cells that plays an important role in facilitating pseudo-allergic reactions as well exacerbating inflammation during asthmatic and other allergic diseases. Lactic acid, a byproduct of anaerobic glycolysis, is abundantly present in inflamed tissues and has been shown to regulate functions of several immune cells. Because the endogenous ligands for MRGPRX2 (substance P and LL-37) are upregulated during pathologic conditions such as cancer and asthma, the role of lactic acid in regulating mast cells response via MRGPRX2 and MrgprB2, the murine orthologue of the human receptor, is important to define. In this study, lactic acid suppressed both the early (Ca2+ mobilization and degranulation) and late (chemokine/cytokine release) phases of mast cell activation; this data was confirmed in LAD2, human skin and mouse peritoneal mast cells. In LAD2 cells, the reduction in degranulation and chemokine/cytokine production mediated by lactic acid was partially dependent on the pH. In agreement with the in vitro studies, lactic acid also reduced passive systemic anaphylaxis induced by compound 48/80 (a known MRGPRX2/MrgprB2 ligand) and inflammation in an LL-37 induced murine model of rosacea that is dependent on MRGPRB2 expression in skin mast cells. This data suggests that lactic acid may serve to inhibit mast cell-mediated inflammation during asthma and reduce immune response during cancer by affecting mast cell activation through MRGPRX2.
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Title: A NUMERICAL AND EXPERIMENTAL INVESTIGATION OF A SUBSURFACE STEP USING FLASH THERMOGRAPHY
Creator: Nejdl, David
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Flash thermography (FT) is a well-established non-destructive testing (NDT) technique that uses a short (~msec) pulse from a flashlamp to uniformly heat the surface of a sample and interrogate its subsurface structure based on the surface temperature response, measured with an infrared (IR) camera. Heat flow into a defect-free sample is described by a 1-D diffusion model, which transitions to higher dimensions due to subsurface discontinuities. 1-D approaches can be unreliable in the vicinity...
Show moreFlash thermography (FT) is a well-established non-destructive testing (NDT) technique that uses a short (~msec) pulse from a flashlamp to uniformly heat the surface of a sample and interrogate its subsurface structure based on the surface temperature response, measured with an infrared (IR) camera. Heat flow into a defect-free sample is described by a 1-D diffusion model, which transitions to higher dimensions due to subsurface discontinuities. 1-D approaches can be unreliable in the vicinity of abrupt thickness change, termed as the ‘transition zone,’ where lateral heat flow from the thin to thick region may mask surface temperature changes due to heat flowing into the part. In this work, we quantify the uncertainty in a “subsurface step,” of a steel sample heated on its front flat and smooth surface, while the thickness (L) of the plate changes with a known step size (dL) on the backside. Finite element models simulating the FT process were developed to understand the effect of sub-surface steps on the thermal diffusion and compared with experiments for 12 varying step (dL/L) combinations. The width of the transition zone was measured using the Thermographic Signal Reconstruction (TSR) method. Results indicate that the transition zone can be defined simply as a function of its geometry. Experiments confirmed that the model predictions work well under the assumption that the steps are properly distinguishable from each other. Lastly, equations to estimate the detectability of a step were developed to be used in addition to the camera’s detection limits. Overall, the approach used can be extended to anisotropic materials such as composites and bonded joints to enable efficient NDT of structural components.
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Title: NATIVE CULTURE AND LANGUAGE EXPERIENCES : SUPPORTING THE HEALTH OF AMERICAN INDIAN/ALASKA NATIVE CHILDREN
Creator: Saucedo, Jessica Sandra
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Native culture and language practice have been identified as core supports that have allowed American Indian/Alaska Native (AI/AN) communities to persevere despite adversity. Native culture and language may be important protective factors against obesity; however, this relationship is understudied in the current literature. High obesity rates among AI/AN young children continue to persist despite Native culture and language practice. Food insecurity is an understudied correlate of obesity and...
Show moreNative culture and language practice have been identified as core supports that have allowed American Indian/Alaska Native (AI/AN) communities to persevere despite adversity. Native culture and language may be important protective factors against obesity; however, this relationship is understudied in the current literature. High obesity rates among AI/AN young children continue to persist despite Native culture and language practice. Food insecurity is an understudied correlate of obesity and its associated health conditions. This study addresses gaps in the existing literature by examining the association between childhood obesity and food insecurity among 2- to 4-year-old AI/AN children, and by examining whether Native culture and language may support resilience. Food insecurity was used to predict obesity, defined as high body mass index, within a sample from the AI/AN Family and Children Experiences Survey 2015 of 476 children who identify as AI/AN alone or in combination with another race. A Native culture practice index and a Native language use scale were used to moderate the relationship between food insecurity and obesity. Ordinary least square regression was used to explore if boys had higher obesity rates than girls; if food insecurity was positively associated with obesity; and if Native culture and language moderated the relationship between food insecurity and obesity. However, these relationships were not statistically significant. Potential reasons for these findings and directions for future exploration are provided.
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Title: DETERMINATION OF THE EFFECTIVE THERMAL CONDUCTIVITY OF PACKED BEDS OF MAGNESIUM-MANGANESE-OXIDE
Creator: Masoomi, Faezeh
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Magnesium-manganese-oxide redox materials have significant potential for thermochemical energystorage; however, the material high-temperature physical properties, in particular, its thermal conductivity are critical for engineering storage devices. In this thesis, the effective thermal conductivity of packed beds of magnesium-manganese-oxide pellets is measured in the temperature range of 300 °C to 1300 °C with a 100 °C span using the transient hot-probe method. The transient hot-probe method...
Show moreMagnesium-manganese-oxide redox materials have significant potential for thermochemical energystorage; however, the material high-temperature physical properties, in particular, its thermal conductivity are critical for engineering storage devices. In this thesis, the effective thermal conductivity of packed beds of magnesium-manganese-oxide pellets is measured in the temperature range of 300 °C to 1300 °C with a 100 °C span using the transient hot-probe method. The transient hot-probe method is a well-established technique to determine the effective thermal conductivity of materials by measuring the transient temperature response of a 1-D heat source with constant heat generation. In this thesis, a thin platinum wire covered by a thin alumina sheet is used as both 1-D heat source, and the temperature measurement device. A constant current is passed through the platinum wire emulating 1-D heat generation. Simultaneously, the electrical resistance of the wire is measured versus time by measuring the voltage across the platinum wire. The wire temperature is calculated based on the wire’s temperature-dependent resistance using a calibration curve established prior to the experiment. The effective thermal conductivity is calculated by curve-fitting a conductivity-dependent model to the wire temperature. The effective thermal conductivity ranges from 0.46 to 1.64 (W/(mK)), and increases significantly with the temperature. The increase in thermal conductivity with temperature is primarily attributed to thermal radiation. The experimental results are compared to a theoretical dual-porosity model, showing good agreement.
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Title: BIOCHAR EFFECTS ON MYCORRHIZAL SYMBIOSES, PLANT GROWTH, SOIL PROPERTIES, AND CARBON STABILIZATION MECHANISMS
Creator: O'Neil, Chase
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Biochar is a porous charcoal-like material produced from pyrolyzing (or heating without oxygen) organic biomass. It is increasingly being researched for its potential to improve soil fertility and soil health, increase agricultural production, and sequester carbon (C) long-term in soils. However, biochar properties vary depending on feedstock and pyrolysis conditions (e.g., temperature, length of time, etc.) and its effects can also differ across soil habitats. My thesis research examines how...
Show moreBiochar is a porous charcoal-like material produced from pyrolyzing (or heating without oxygen) organic biomass. It is increasingly being researched for its potential to improve soil fertility and soil health, increase agricultural production, and sequester carbon (C) long-term in soils. However, biochar properties vary depending on feedstock and pyrolysis conditions (e.g., temperature, length of time, etc.) and its effects can also differ across soil habitats. My thesis research examines how biochar amendments can alter soils and the broader impact it may have on agroecosystems. In my first chapter, I sought to understand how different biochar types and nutrient additions could impact plant symbioses with arbuscular mycorrhizal fungi (AMF) through a six-month greenhouse experiment. My results indicated that biochars can mitigate low soil nitrogen (N) and phosphorus (P) levels for plant growth and that N from organic substrates was utilized by AMF more than P from organic substrates. These findings can inform agroecosystem weed management practices when amending soils with nutrients or biochar. In my second chapter, I examined how biochar type and application rates may impact soil C stabilization mechanisms in different soils for one-year and four-year aged samples. Overall, I found the wood-based biochar and the higher application rates to have the greatest effects, which were strongest in the coarsest soil type. Both biochars showed evidence that their recalcitrant structure influenced their stabilization, potentially more than other processes such as aggregation or organo-mineral associations, although this may change over time. Thus, I found biochar can be used to sequester C, improve soil health, and maintain sustainable agroecosystems.
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Title: DEVELOPMENT OF FINE-MAPPING RESOURCES FOR INTERROGATION OF A YIELD IMPACTING QTL ON THE 2D CHROMOSOME IN A BREAD WHEAT (TRITICUM AESTIVUM) AND AEGILOPS TAUSCHII NESTED ASSOCIATION MAPPING POPULATION
Creator: Turkus, Jonathan Dubau
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Bread wheat (Triticum aestivum) is one of the dominant grain crops across the world. As a mainstay of diets across the world, there is a constant pressure by the breeders and geneticists to identify yield promoting loci. In previous work, significant SNP associations were found on the 2D chromosome (approximately at 23.5Mb and 25.2Mb) for yield variation in a genome-wide association study (GWAS) of the D-genome Nested Association Mapping population (DNAM), an advanced-backcross nested...
Show moreBread wheat (Triticum aestivum) is one of the dominant grain crops across the world. As a mainstay of diets across the world, there is a constant pressure by the breeders and geneticists to identify yield promoting loci. In previous work, significant SNP associations were found on the 2D chromosome (approximately at 23.5Mb and 25.2Mb) for yield variation in a genome-wide association study (GWAS) of the D-genome Nested Association Mapping population (DNAM), an advanced-backcross nested association mapping population of five Ae. tauschii lines into an elite bread wheat background. To identify the signal source more precisely, fine-mapping tools were created in this work. Seven Kompetitive Allele Specific PCR (KASP) primer sets were designed for SNP markers between 22Mb and 30Mb, six of which displayed codominant behavior and one dominant. The KASP primer sets were identified the U6718 BC1F1 subpopulation within the DNAM as segregating for bread wheat and Ae. tauschii alleles between 22Mb and 30Mb on 2D chromosome. Linkage maps were created for the seven D-genome chromosomes for the U6718 subpopulation. QTL analysis defined the QTL as being between 21.3cM to 28.3cM on the 2D linkage map and 23.3Mb to 30.3Mb on the physical map. Using the defined 2DS QTL and the KASP primer sets, a fine-mapping population was created consisting of five heterozygous inbred families fixed 16 unique recombination events across the 2DS QTL. These developed tools will prove instrumental tools towards refining the understanding of causal loci of this yield QTL.
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Title: Exploring the Impacts of Stream-Lake Interactions on the Biogeochemistry of Arctic Headwater River Networks on the North Slope of Alaska
Creator: Haines, Emma Louise
Date: 2021
Collection: Electronic Theses & Dissertations
Description: As a result of global climate change, the Arctic region is warming at twice the rate of the rest of the planet, releasing terrestrially stored carbon and nutrients that were previously frozen in permafrost soils. As the Arctic continues to experience permafrost degradation, as well as shifts in the timing, magnitude, and duration of precipitation extremes and the restructuring of terrestrial vegetation communities, it is predicted that the transport of carbon and nutrients from land to water...
Show moreAs a result of global climate change, the Arctic region is warming at twice the rate of the rest of the planet, releasing terrestrially stored carbon and nutrients that were previously frozen in permafrost soils. As the Arctic continues to experience permafrost degradation, as well as shifts in the timing, magnitude, and duration of precipitation extremes and the restructuring of terrestrial vegetation communities, it is predicted that the transport of carbon and nutrients from land to water will increase. The enhanced release of nutrients and carbon from land to water is already evidenced by increasing fluxes of biogeochemical solutes at the outlets of most large Arctic rivers. To better understand the fate of hydrologically mediated carbon and nutrient mobilization and transformations in Arctic landscapes, attention has recently turned to monitoring spatial and temporal patterns of biogeochemistry in intermediate-scale watersheds (<200 km2). However, within these same watersheds, there is emerging indirect evidence that “stream-lake interactions”, the interruption of streamflow by lakes that are nested within a river network, can modify or confound the biogeochemical signals that are observed at river outlets. Here, I conducted two studies that directly explore how stream-lake interactions alter spatial and temporal biogeochemical signals in two permafrost-dominated headwater river networks located on the North Slope of Alaska. First, I analyzed water chemistry from repeated “synoptic” sampling campaigns that occurred in June and August over three years (2016-2018) in the Oksrukuyik Creek watershed. This data includes a suite of biologically reactive solutes (dissolved carbon, nitrogen, and phosphorus species), and numerous other geogenic solutes (SO42-, Si, Ca, Cl, Na, Ba, and Fe). To better understand the role of lake residence time in altering stream solute chemistry, I analyzed data from three distinct subcatchments within the Oksrukuyik watershed: those with no lake presence, intermediate lake presence, and a lake-dominated system. Second, I investigated the role of high-flow events on upstream to downstream biogeochemical signals in a single Arctic lake (Lake I8) during the 2019 thaw season. I used data from novel high-frequency, in-situ water quality sensors installed at the stream inflow and outflow of the lake. These two studies found evidence that stream-lake interactions do alter biogeochemical signals, and specifically that: 1) lake residence time will determine the capacity for a lake to process nutrients and carbon, where lakes with higher residence time will have greater effects and 2) that the ability for the lake to retain and process inputs from storm events will be greatest in the late thaw season. Together, these studies indicate that stream-lake interactions can modulate biogeochemical conditions, including solute fluxes, through Arctic river networks. Hence, incorporating steam-lake interactions into future landscape biogeochemical studies of Arctic regions with lakes presents an opportunity to advance Arctic system science.
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Title: AGRICULTURAL ADAPTATION, MITIGATION, AND CONSTRAINED CHOICES : EVIDENCE FROM THE U.S. MIDWEST
Creator: Beethem, Kristina K.
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Agriculture is simultaneously vulnerable to and a contributor to a number of environmental issues, such as water quality, soil degradation, and climate change. Agricultural management practices provide one method for both adapting to the threat of environmental problems and mitigating those same problems. However, farmers make these decisions within a broader socio-economic context which influences and sometimes constrains their choices. In this paper, I build on the existing agricultural...
Show moreAgriculture is simultaneously vulnerable to and a contributor to a number of environmental issues, such as water quality, soil degradation, and climate change. Agricultural management practices provide one method for both adapting to the threat of environmental problems and mitigating those same problems. However, farmers make these decisions within a broader socio-economic context which influences and sometimes constrains their choices. In this paper, I build on the existing agricultural practice adoption literature by utilizing treadmill of production theory to examine the factors that predict farmers’ use of practices to adapt to or mitigate issues like climate change. My empirical analysis uses structural equation modeling with latent variables (SEMLV) to study 2019 survey data from farmers in Illinois, Indiana, Michigan, and Ohio. Results indicate that farmers’ attitudes, beliefs, and environmental awareness differentially predict adaptation and mitigation practice use. These findings suggest that adaptation to protect crop yield and farm income is promoted under the current treadmill system, while mitigation to ameliorate problems beyond the scope of the farm is constrained.
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Title: A Molded Paper Pulp Packaging Design Using Topology Optimization Method
Creator: Bahlau, Jacob
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Molded Paper Pulp (MPP) is a form of packaging that has become widely used because of the environmental and economic benefits. The most common MPP design method would be creating different prototypes based on the engineer’s knowledge and experience and analyzing each model to determine which model has the best design. However, this trial-and-error design method is a costly and time-consuming process. To overcome these drawbacks, topology optimization will be looked at being incorporated into...
Show moreMolded Paper Pulp (MPP) is a form of packaging that has become widely used because of the environmental and economic benefits. The most common MPP design method would be creating different prototypes based on the engineer’s knowledge and experience and analyzing each model to determine which model has the best design. However, this trial-and-error design method is a costly and time-consuming process. To overcome these drawbacks, topology optimization will be looked at being incorporated into the MPP design process. Topology optimization is a structure optimization method based on a Finite Element Analysis (FEA) and a sensitivity analysis. It has been widely used in various industries because of the design efficiency. However, the topology optimization method has not been applied into the packaging industry. The main reason is because of the limited design space of packaging and manufacturability. This thesis presents a methodology to find the optimal design of the MPP using the topology optimization method and post processing. First, the critical area is defined using a topology optimization result under a given boundary condition. Second, the topology optimization results will be superimposed to the MPP design space again. Lastly, the supporting rib structure will be added to finalize the MPP design process. Once the design is completed, the optimal design is compared to the original design to evaluate the improvement. In this thesis, MPP wine shipper is used as an example. The proposed method was able to present a new design using the topology optimization method. To demonstrate the efficiency of the new design, FEA results are presented, and the new design shows a lower stress concentration compared to the typical MPP wine shipper design in the market.
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Title: CHARACTERIZATION AND IDENTIFICATION OF CRYSTALLINE STRUCTURES IN CANNABIS SOLVENT EXTRACTS
Creator: Abraham, Otyllia Ruth
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Cannabis solvent extracts comprise of a variety of products formed through the isolation and concentration of cannabinoids from either marijuana or hemp using organic solvents. Marijuana and hemp represent two broad classes of Cannabis sativa plants and are distinguished based on the concentration of the psychoactive cannabinoid delta-9-tetrahydrocannabinol (Δ9-THC). A common marijuana solvent extract is butane hash oil, which uses butane to extract and concentrate Δ9-THC and its naturally...
Show moreCannabis solvent extracts comprise of a variety of products formed through the isolation and concentration of cannabinoids from either marijuana or hemp using organic solvents. Marijuana and hemp represent two broad classes of Cannabis sativa plants and are distinguished based on the concentration of the psychoactive cannabinoid delta-9-tetrahydrocannabinol (Δ9-THC). A common marijuana solvent extract is butane hash oil, which uses butane to extract and concentrate Δ9-THC and its naturally occurring acidic form, delta-9-tetrahydrocannabinolic acid (Δ9-THCA). Hemp solvent extracts, however, typically isolate cannabidiol (CBD). This work aimed to comprehensively characterize marijuana and hemp-derived solvent extracts using optical and chemical techniques. Optical analysis via polarized light microscopy (PLM) was performed to characterize crystalline materials present in both subsets of extracts and indicated the possibility to differentiate marijuana and hemp extracts based on optical differences. Chemical characterization through infrared spectroscopy and single crystal X-ray diffraction provided the identification of the crystalline component (THCA for marijuana extracts and CBD for hemp extracts) and supported the PLM findings. Additionally, the derivatization procedure (focusing on reaction temperature, reaction time, and solvent ratio) for THCA using a common silylation reagent was optimized using full factorial experimental design to allow for the analysis of the solvent extracts by gas chromatography-mass spectrometry.
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Title: THE IMPACT OF DATA GRANULARITY AND STREAM CLASSIFICATION ON TEMPERATURE GRADIENT MODELING IN MICHIGAN’S STREAMS
Creator: Dertli, Halil Ibrahim
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Stream temperature is an important parameter of water quality and developing models capable of reliable predictions are critically important in stream management. In addition to the structure of these models (e.g., predictive variables), there are other factors that may influence model performance such as the selection of data granularity (i.e., level of temporal aggregation) and seasonal coverage of data collection. Data granularity and seasonal extent of data collection vary widely in the...
Show moreStream temperature is an important parameter of water quality and developing models capable of reliable predictions are critically important in stream management. In addition to the structure of these models (e.g., predictive variables), there are other factors that may influence model performance such as the selection of data granularity (i.e., level of temporal aggregation) and seasonal coverage of data collection. Data granularity and seasonal extent of data collection vary widely in the literature and have often been arbitrarily selected in stream temperature modeling studies in the past, but the consequences of these choices have not been explored. I applied different data granularity and time period selections to regression models, which were developed by Andrews (2019) to predict temperature gradient (i.e., stream temperature change) in Michigan’s streams. Applying higher data granularity increased overall model performances and changed model selection results, however applying different time periods did not have a substantial effect on model performances. Using higher data granularity also changed model parameter estimates by increasing the multicollinearity in best-fitting models. In addition to temporal data granularity, data may be pooled spatially across streams within a thermal class to reduce the costs of data collection. I examined the impact of stream classification on model performance by applying data pooling within stream classes. Stream-Specific Models had better performance compared to Class-Based Models. Additional analyses suggested that classifying streams based on temperature gradient instead of stream temperature may result in better Class-Based Model performance.
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Title: EFFECTS OF AMINO ACID AND FATTY ACID SUPPLEMENTATION ON PRODUCTION RESPONSES OF LACTATING COWS
Creator: Negreiro, Ariana Nicole
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Addition of fatty acids (FA) and amino acid (AA) supplements to dairy cow diets is becoming common practice due to the growing demand to increase milk fat and milk protein yields. This thesis contains two studies that evaluate the effects of supplemental palmitic (C16:0) and oleic (cis-9 C18:1) acids, and methionine (Met) and lysine (Lys), on lactating dairy cows. The first experiment used a product containing 80% C16:0 + 10% cis-9 C18:1 supplied at 1.5% diet dry matter (DM) and supplemental...
Show moreAddition of fatty acids (FA) and amino acid (AA) supplements to dairy cow diets is becoming common practice due to the growing demand to increase milk fat and milk protein yields. This thesis contains two studies that evaluate the effects of supplemental palmitic (C16:0) and oleic (cis-9 C18:1) acids, and methionine (Met) and lysine (Lys), on lactating dairy cows. The first experiment used a product containing 80% C16:0 + 10% cis-9 C18:1 supplied at 1.5% diet dry matter (DM) and supplemental Met and Lys in low forage diets (LF) and a control diet with no added FA or AA at typical midwestern forage content (CON). Compared with CON, LF increased dry matter intake (DMI), milk fat yield, milk protein yield, energy-corrected milk (ECM) yield, and body condition score (BCS). In the second experiment, different ratios of palmitic (C16:0) and oleic (cis-9 C18:1) acid were supplemented in basal diets containing high CP without supplemental AA (HP) or low CP with supplemental AA (LP). FA treatments were products consisting of 80% C16:0 + 10% cis-9 C18:1 (PA) and 60% C16:0 + 30% cis-9 C18:1 (OA) supplemented at 1.5% diet DM and a non-FA supplemented control diet (CON). No interactions were observed between basal diet and FA treatment for the yields of milk or milk components. Compared with HP, LP decreased milk urea nitrogen and blood urea nitrogen concentrations, and did not impact milk, milk fat, or milk protein yields. FA treatments decreased DMI and increased milk yield, fat yield, ECM yield, and feed efficiency. Results from this work can provide information that can be used as a foundation for future studies and to guide feeding decision to maximize performance and farm income.
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Title: Toward Stress-Aligned Lattice Design
Creator: Gao, Qiren
Date: 2021
Collection: Electronic Theses & Dissertations
Description: A novel approach to designing lattice structures is presented in which lattice members are aligned with the principal stress directions, and the lattice spacing and member sizing are optimized simultaneously to obtain an optimized design. By allowing both the lattice layout and the member sizes to vary during a multi-level design optimization process, this approach allows a greater flexibility in searching the design space and finding potentially higher performing designs than standard...
Show moreA novel approach to designing lattice structures is presented in which lattice members are aligned with the principal stress directions, and the lattice spacing and member sizing are optimized simultaneously to obtain an optimized design. By allowing both the lattice layout and the member sizes to vary during a multi-level design optimization process, this approach allows a greater flexibility in searching the design space and finding potentially higher performing designs than standard topology or triangularization methods. Example applications amply illustrate the capability of this approach to produce high quality designs.
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