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GREAT LAKES AND ITS REGIONAL CLIMATE IN THE FUTURE
Full text linkThe overarching objective of this dissertation is to enhance our predictive understanding of the Great Lakes regional climate by utilizing advanced modeling techniques and provide comprehensive insights into the future of the Great Lakes. This dissertation focuses on four areas pertinent to the future of the Great Lakes hydroclimate and extreme events, beginning with the derivation of robust water level projections for the Great Lakes in Chapter 2. Using a regional climate modeling system with a two-way coupled three-dimensional (3D) hydrodynamic lake and ice model for the Great lakes, we analyze long-term future changes in the over-lake precipitation, lake evaporation, and basin runoff under climate change and provide insights into future hydrological trends. In Chapter 3, we employ a storyline approach and focus on a unique Great Lakes coastal hazard, lake-effect snow (LES) storms. Specifically, we create a storyline that describes a physically self-consistent unfolding of the November 2022 Buffalo, New York LES storm under the warmer future climate. Our storyline provides one of many plausible futures for the Buffalo LES storm and answers the societally relevant question of what could happen to the storm under a warmer climate. In Chapter 4, we explore the novel concept of subsurface heatwaves in the Great Lakes. With thermal extremes becoming more prominent in recent decades, our first-of-its-kind examination of subsurface heatwaves offers a unique perspective on Great Lakes warming from a vertical standpoint. This study highlights how aquatic species are being forced to adapt to the deepening of thermal refuges and increasing of compound heatwaves, shedding light on the ecological impacts of these emerging thermal extremes. Lastly in Chapter 5, we delve deeper into the behavior of regional climate modeling systems, which are the primary tool for climate change research. More specifically, we explore the influence of lake-atmosphere interaction on the simulated lake surface temperature within a newly developed regional climate modeling system. We use a twin experiment to evaluate the impact of a two-way coupling between an atmosphere model and a 3D hydrodynamic lake and ice model on the simulated summer lake surface temperature through lake-atmosphere interactions. The insights from this study provide crucial information on how, in a two-way coupled system where errors or biases are allowed to freely propagate, lake surface temperature is modulated through surface heat fluxes which influence various meteorological state variables that interact with lake surface temperatures
TRANSIENT THERMAL FINITE ELEMENT SIMULATION FOR PROCESS MODELING IN WIRE ARC ADDITIVE MANUFACTURING
Full text linkThis thesis presents the development of a transient thermal framework for Wire Arc Additive Manufacturing (WAAM) created using ANSYS Workbench. This study aims to understand the inherent properties and thermal behavior of WAAM by using the Finite Element (FE) simulation technique to reduce the need for experiments. Specifically, the transient thermal WAAM simulation framework uses the heat source Goldak model to understand the thermal behavior for a given voltage, initial temperature, and travel speed during the process to predict process temperature. The outcomes of this thesis aim to significantly decrease material waste and repetitive experiments and accelerate production process design for WAAM. Furthermore, this study also provides a solution to predict quality metrics for WAAM to select appropriate process parameters
ENVIRONMENTAL AND SILVICULTURAL FACTORS ASSOCIATED WITH NORTHERN WHITE-CEDAR (THUJA OCCIDENTALIS) SEEDLING REGENERATION IN HARVESTED LOWLANDS
Full text linkNorthern white-cedar (Thuja occidentalis) plays a vital ecological and cultural role in North America\u27s eastern hemi-boreal forests, yet its regeneration is often sparse and difficult to manage, especially in lowland conditions. To assess factors influencing cedar seedling densities, we surveyed 430 plots across 135 harvested cedar-dominated lowland stands (1–72 years post-harvest) over a broad geographic region. Most plots (73%) harvested in the last century and 90% of those harvested in the last decade had absent or understocked cedar seedling densities (0–5000/ha). Seedling density increased with time-since-harvesting, density of retained overstory cedar trees, denser canopy closure, and decreased with distance from the harvest edge into openings. Seedling presence also positively correlated with greater coarse woody debris, higher moss cover, cooler maximum summer temperatures, and higher soil pH. These findings highlight key site conditions and management practices that promote long-term cedar regeneration, providing guidance for sustainable forestry in these ecosystems
ANSI Z97 Impact Testing of Thin Glass
Full text linkTo determine whether thin glass constructions can pass Z97 impact test to qualify as safety glass an extensive protocol was performed. Constructions including monolithic, chemically strengthened, filmed, laminated, and triple pane insulated glass units comprised of thin glass ranging in thickness between 0.50 mm and 1.6mm were evaluated. Test results indicate annealed specimens, and laminated specimens performed similar to constructions with 3 mm and 6 mm glass. Specimens with 0.2 mm film consistently performed as safety glass for thicknesses between 0.7 mm and 1.6 mm and similar performance for specimens with 0.1 mm film with thickness of 1.1 mm and greater
BARBIE VLOGGER AS TEEN INFLUENCER FOR LITTLE GIRLS
Full text linkMattel’s YouTube Barbie Vlogs series (2015-2022) targets 6–11-year-old girls with short narratives and prosocial messages addressing their prevalent interests and everyday experiences. While the vlog is clearly an attempt by Mattel to appeal to a market sector that includes both little girls and their Millennial parents, this analysis examines Barbie Vlogger as a social media influencer in order to explore how little girls learn to become older girls through the performance of teenage girlhood as enacted in the Barbie Vlogs. What is Barbie doing in the vlogs to show little girls who a teen girl is and what she does and to prepare them for challenges and opportunities? The study frames the Barbie Vlogs and the Barbieverse within neoliberal feminist and popular feminist critiques and the work of Girlhood Studies scholars. The analysis proceeds in three parts. First, the vlogs are analyzed through a content analysis informed by Barton’s (2002) rich feature analysis and Reinharz and Kulick’s (2007) feminist content analysis, as well as Lazar’s (2007) feminist critical discourse analysis. This analysis finds evidence that Barbie reflects the neoliberal feminist narrative as a “can-do” girl who models self-reflection, positive familial and friendship relations and skills, and the value of a girl’s inner life and self-expression. Then, the content analysis is reframed through a critical discussion about girls’ mental health, children’s media consumption, and cultural illusions and anxieties over the young girl, and if Barbie can meaningfully address those through her vlogs, raising critical questions for further study. Third, two semi-structured focus groups were conducted with girls ages 5–9 who were members of a preestablished local girl-based group. The girls watched three Barbie Vlogs and responded to questions about their familiarity with and reaction to Barbie. The analysis finds that the style of direct address in the vlogs did not hold girls’ attention but girls who liked Barbie did respond positively to Barbie’s thematic emphasis on neoliberal postfeminist expression of self-identity and maintaining a can-do attitude, and asks how neoliberal feminism might offer nascent feminism to little girls. This study offers theoretical and practical implications focused on the empowerment discourse, girls’ media production and consumption practices, and cultural expectations of girlhood. It concludes with methodological recommendations for scholars who want to study little girlhood
Seasonal effects of plant functional groups on molecular biogeochemistry of dissolved organic matter in porewater of a poor fen
Full text linkClimate change may transform peatlands from net carbon (C) sinks to C sources, which could result in a positive feedback to global warming. Warmer temperatures might lower water tables, increase the abundance of shrubs, slow Sphagnum and sedge growth and further accelerate the decomposition of dissolved organic matter (DOM) with a concomitant release of C from the surface. Studies in which vascular plant functional groups (PFGs) in peatlands have been manipulated to mimic the potential effects of a warming climate on DOM are scarce. In the subject study, seasonal effects of PFGs on the molecular composition of DOM of peat porewater were investigated in manipulated plots of a poor fen in Nestoria, Michigan, United States. The organic molecular composition of the peat porewater exhibited strong interactions with PFG and season. Monomeric substances (e.g., monosaccharides and amino acids), which are found in root exudates and are also the products of decomposition of polymeric substances, were least abundant early in the growing season and increased in abundance late in the season. High levels of DOC and proteinaceous substances and an unlikely abundance of total phenolic substances in sedge plots with Sphagnum were attributed (1) to rapid decomposition of labile compounds in the oxygen-rich microenvironment surrounding sedge roots and preservation of more recalcitrant substances or (2) to contributions of lignin-like substances by Sphagnum. Tannin- and lignin-like compounds in the Ericaceae plots with Sphagnum were attributed to inputs of the woody biomass. The refractory organic substances apparently persisted due to a combination of rhizosphere anoxia and suppression of free-living saprotroph activity by the Ericoid mycorrhizal fungi. Through a novel analytic approach, which included organic compound class analysis, determination of spectral indices, and molecular analysis by ESI-UHR-MS, we observed indirect evidence of the complexation of proteinaceous substances by tannin-like substances and the apparent reaction of phenolic moieties of lignin-like substances with amino sugars. A synergistic effect between sedge and Ericaceae was likely responsible for rapid decomposition of DOM in plots with Sphagnum in which vascular PFGs were unmanipulated. Observing the effects of vascular PFGs on seasonal variations of the molecular composition of DOM will improve predictions of the short- and long-term storage of C in peatlands in a changing climate
Towards Universal Non-Dimensional Characterization of the Oscillatory Dynamics of Wind Turbine Rotors of Multiple Sizes
Full text linkOne concern in the field of Horizontal Axis Wind Turbines (HAWTs) is what control strategies are needed to handle gust pulses in the wind to prevent extreme oscillations of the blades to reduce fatigue stress, prevent blade rupture, and extend the turbine’s operational life. In order to design innovative control strategies to modify the blade’s oscillatory response, it is crucial to establish the fundamental vibrational behavior of the blades when excited by gust pulses of different frequencies and amplitudes present in the fluctuating wind inflow. In a series of previous works, the authors presented a novel Reduced-Order Characterization (ROC) technique that provided an energy-based characterization of the fundamental modes of oscillation of wind turbine rotors when excited by combinations of wind gust pulses of different frequencies and amplitudes. The main focus of the present work is to extend these original notions of energy-based ROC to a universal technique expressed in terms of non-dimensional quantities that could be applied to turbines of any size, operating in any set of wind conditions, as long as they share geometrical and material similarity. The ROC technique provides a simple formula that is capable of predicting the dominant vibrational modes of a blade with sufficient precision to be useful in the determination of a control decision that can be computed in real time, an aspect of fundamental importance in dealing with rapid fluctuations in wind conditions
Exploring the effects of excipients on complex coacervation
Full text linkComplex coacervation is an associative liquid–liquid phase separation phenomenon that takes place due to the electrostatic complexation of oppositely-charged polyelectrolytes and the entropic gains associated with the release of bound counterions and rearrangement of solvent. The aqueous nature of coacervation has resulted in its broad use in systems requiring high biocompatibility. The significance of electrostatic interactions in coacervates has meant that studies investigating the phase behaviors of these systems have tended to focus on parameters such as the charge stoichiometry of the polyions, the solution pH, and the ionic strength. However, the equilibrium that exists between the polymer-rich coacervate phase and the polymer-poor supernatant phase represents a balance among attractive electrostatic interactions and excluded volume repulsions as well as osmotic pressure effects. As such, we hypothesize that it should be possible to tune coacervate phase behavior via the addition of non-electrostatic excipients which would partition between the two phases and potentially alter both the solvent quality and the osmotic pressure balance. In particular, our work focuses on small molecule excipients such as sugars, amino acids, and other additives that have a history of use in vaccine formulation. We quantified the ability of these excipients to partition into the coacervate phase, and their potential for destabilizing the phase separation. Furthermore, we demonstrate that these additives can be combined with complex coacervation in the context of a virus formulation
The influence of culpability, harm to animals, and professional education on attitudes about killing animals in the name of conservation
No full textWild animals of particular species are increasingly killed in the name of conservation (KITNOC). That is, in the name of achieving traditional goals of conservation. Attitudes about KITNOC are not well studied. We sought to understand whether attitudes about KITNOC among college students are associated with their professional education. To do so, we surveyed current and recently graduated college students (n = 398) from seven major universities in Iran between January and March 2022. These respondents were from four disciplines: environmental science, veterinary science, engineering, or law. The survey elicited attitudes for three different scenarios, involving trophy-hunting lions, killing free-ranging dogs, and killing pythons. While attitudes varied considerably among the scenarios and among individuals, there was an overall tendency to oppose KITNOC. While receiving an education in environmental science was associated with KITNOC attitudes, the association was not strong enough to result in group-level differences between those receiving different kinds of education. More positive views about KITNOC tended to be held by males and those expressing more support for anthropocentric beliefs – all else being equal. The strongest associations were that opposition to KITNOC was greatest among those who thought it is more important than others to consider: (i) less harmful methods of solving the conservation problem, and (ii) that humans, not the animals to be killed, were culpable for the conservation harms. These results imply the values that should be addressed when decisions about KITNOC are developed. We recommend fostering value-based discussions in conservation policy that address culpability and harm
Enhancing the High-Temperature Performance and Aging Resistance of Bioasphalt by Composite Modification
No full textThe aim of this study is to enhance the high-Temperature performance and aging resistance of bioasphalt by composite modification. Biorubber composite-modified asphalts with waste rubber powder and various amounts of bio-oil were researched. Meanwhile, the control groups were bioasphalt and rubber asphalt. The aging simulation of asphalt was conducted in laboratory tests. Moreover, the rotational viscosity, viscoelastic properties, deformation resistance, antiaging properties, and crack resistance of asphalt were explored in this study. The addition of rubber powder was found to increase the rotational viscosity of bioasphalt to some extent, but it can still meet the technical requirements for construction workability. The rubber powder swells in asphalt, which increases the elastic component of binder and its complex shear modulus. Consequently, the biorubber composite-modified asphalt demonstrates outstanding resistance to high-Temperature rutting and aging, as well as superior low-Temperature cracking resistance. Optimal antirutting and crack resistance were attained with 10%-15% bio-oil, and the best aging resistance was achieved with 10% bio-oil. Short-Term aging promoted the polymer chains of rubber powder to absorb more light components, forming more gel-like substances that were unevenly distributed in the binder system, thereby reducing the fluidity of asphalt and enhancing the flow activation energy. Incorporating rubber powder significantly enhanced the asphalt\u27s resistance to permanent deformation under low stress levels and exhibited excellent resistance to deformation under high stress levels. The recommended composite-modified asphalt incorporates 10%-15% bio-oil