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"My kind of librarian or your kind of librarian?": Information Seeking Behavior in <i>Supernatural</i>
Get PDFUncorrected proof.This essay explores how the main characters in the television series Supernatural use libraries and archives to aid in their work as hunters of supernatural creatures.YesNon-blind review by the book editors
Mechanical characterization and analysis of FDM 3D printed copper samples
No full textAdditive manufacturing, specifically 3D printing, technology has revolutionized the design, creation, and building of parts and engineering objects. The fused deposition modeling (FDM) or UV-cured resin-based 3D printings are widely used techniques for rapid prototyping today. The prototypes are typically made of various thermoplastics such as acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and polyethylene terephthalate glycol (PETG) with each thermoplastic having different properties. However, FDM or resin-based 3D printing cannot manufacture metal parts due to some inherent engineering challenges, such as the requirement of the extremely high melting temperature of the metals, making metal filaments, and involved complex thermal management. This thesis research has explored and studied the possibility of manufacturing metal parts using an ordinary FDM 3D printer, a specialized kiln, and PLA-Cu filament with 80% - 90% of copper (Cu) contents. The parts were debound and sintered in the kiln to burn off the PLA, which allowed the Cu to bond to create pure Cu parts. The 3D printing flow rates, debinding and sintering times in the kiln were varied to understand the effect of these parameters on the material characteristics and mechanical strength of the printed Cu samples. The ASTM D638 samples were 3D printed at three flow rates: 133%, 135%, and 140% in an FDM printer and debound and sintered at three different times: 3 hour debind 3 hour sinter, 3 hour debind 4 hour sinter, and 3 hour debind 5 hour sinter. The dimensions and weight of the samples were measured before and after sintering. Samples were polished and etched using a 5-step polishing method with different grinding grits (coarse to ultrafine) and etched with ferric chloride. Grain boundaries and surface qualities of the 3D printed and sintered samples were observed under a high-precision material microscope, stored, and compared with the cold-rolled annealed copper samples. The tensile strength of the samples was evaluated using Universal Testing Machine (UTM). The results show that the 135% 3-hour debind and 4- hour sinter provided the best overall results for the least amount of void within the sample, nicer grain boundaries and mechanical strength. The average stress vs strain value for cold rolled annealed copper is 220.6 Mpa. The results from the tensile testing came out to have a maximum of 39.107 MPa in the 133% flow rate 3 hour debind 4 hour sinter. The second highest stress value came from the 135% flow rate 3 hour debind 4 hour sintering time group at 37.29 Mpa. While the quality and material grain boundaries are comparable with cold-rolled annealed samples, the mechanical characteristics are far off. Nonetheless, the overall aspect of making copper parts from conventional FDM-based 3D printing technology is promising. The findings of this research will contribute to understanding and better utilization of FDM-based 3D printed Cu and general metal parts for future engineering endeavors
Why are there so many birds in the tropics: using comparative approaches to investigate the confluence of landscape, ecology, and genome in the generation of Neotropical avian diversity
Get PDFThe Neotropics are home to an astonishing level of avian diversity, and thus naturally a focus for the study of the generation of biodiversity. Studies of tropical speciation often focus on large-scale landscape changes, such as the impacts of Pleistocene climate change, the formation of the isthmus of Panama, or the uplift of the Andes. However, the full scope of Neotropical avian diversity is not yet wholly understood, and increasing evidence suggests that other processes beyond these geographical factors contribute to speciation in tropical birds. Here, I examine genetic data, from mitochondrial markers to whole genomes, in a diverse array of Neotropical birds, to better understand the interplay between landscape, genome, and ecology in the development of reproductive isolation. In my first chapter, I use mitochondrial barcodes from over 2,000 birds to detect potential cryptic species across Panama. I find that species-level splits occur in 19% of sampled species, suggesting avian diversity in Panama is substantially underestimated. These disproportionately occurred in species with ecological characteristics associated with low dispersal ability. This is reinforced by the next chapter, in which I use reduced-representation genomic data in ten taxa of lowland Panamanian birds to test whether time is the most important predictor of the outcomes of secondary contact. I find no evidence that time plays a role in determining hybrid zone width in these taxa, and only a partial role in the generation of genomic variation. Instead, diet, which is again linked to dispersal ability as well as demographic changes, is a much better predictor. Finally, I move my focus in Chapter 3 to the Andes, using low-coverage whole genomes to examine the speciation history of the hummingbird genus Aglaeactis. This rapid radiation has significant mitonuclear discord, with completely different phylogenies reconstructed from mitochondrial and nuclear markers. In the two clades defined in the nuclear data, each made of three taxa, I then examined how divergence was distributed across the genome. The three southern taxa, all of which are in allopatry, have overall higher genomic divergence, but it is spread evenly across the genome. In the northern clade, though, I find much lower divergence punctuated by outliers of elevated differentiation. These northern taxa do have contact zones between them, and it is likely that gene flow in that geographic scenario has had a hand in shaping the genomic landscape for the development of reproductive isolation. Taken together, each of these chapters explores how reproductive isolation is the outcome of multiple facets of an organism interacting, and sheds further light on how avian biodiversity is generated
SHAREOK Institutional Repository: University of Oklahoma Policies and Guidelines
No full textThis document is intended to guide the use of SHAREOK sub-communities and collections of the University of Oklahoma, which includes the following communities and the sub-communities and collections therein: The University of Oklahoma, Native American Resources, Oklahoma Supercomputing and Cyberinfrastructure, and Oklahoma Transportation Resources / Oklahoma Transportation Library. An associated item, SHAREOK File Formats, can be found at https://shareok.org/handle/11244/330046
Light and Place: Robert Irwin and Others in Southern California
Get PDFThis dissertation argues that the clement climate and habitability of Southern California, as well as the rhetoric that enveloped its promotion over the course of a century, informed a specific mode of creation and representation of place in painting, photography, light-based installations, and architecture. These architectural and artistic interventions on and about Southern California conjure light to illuminate the ideal habitability of the place in question and attract viewers to images and environments that arouse sensorial responses. In the built environment, the creation of place is performed through a transparency of partitions between indoor and outdoor spaces that facilitate light infiltration, as well as through adaptability to the specific features of the site and careful consideration of the dweller’s sensorial reactions. Southern California artist Robert Irwin in particular, provides a key for the interpretation of this peculiar rapport to place. Irwin’s light installations respond to as well as embody Southern California, by assessing through light its habitability, and by responding to the dialogue of indoor and outdoor spaces experienced in Southern California dwellings at midcentury. More specifically, I contend that the light installations of Robert Irwin act as a quintessentially Southern California contemplation on the phenomenon of place by mediating the genius loci of the region through the architectural detail of the window-wall
Genetic Architecture and Influence of Switchgrass Internode Anatomy on Biofuel Production-Relevant Traits
Get PDFBiofuels produced from plant biomass, such as switchgrass, have the potential to mitigate the increasing pace of rising atmospheric CO2 and global temperatures caused in part by the burning of fossil fuels. Biofuels produced from photosynthetically sequestered carbon in plant cell walls represent a contemporary capture-and-release cycle of carbon, compared to the net increase of carbon released into the atmosphere when burning fossil fuels. The main needs of biomass improvement for biofuels to become a viable alternative to fossil fuels are to (1) increase biomass yield and (2), improve biomass composition to increase biomass deconstruction efficiency. The anatomy of switchgrass tiller internodes remains intact even after standard mechanical deconstruction of biomass prior to chemical deconstruction. However, the impact of internode anatomy on biomass deconstruction efficiency is poorly understood. Furthermore, current understanding of internode anatomy plasticity in genotype clones caused by varied conditions across environments in this context is also lacking. Therefore, our goal is to explore the influence of internode anatomy variation on biofuel-relevant traits in switchgrass biomass and to increase our understanding of genetic control of internode anatomy variation.
This research analyzed internode anatomy of lowest above ground internodes in clones of upland (VS16, DAC) and lowland (AP13, WBC) switchgrass genotypes at three common garden sites in: South Texas, Central Missouri, and Central Michigan. Cortical cell wall thickness (CWT) varies independently of 21 other traits measured and suggests unique genetic control may be present for optimization. Cortical cell wall thickness also negatively correlates with digestion efficiency and mild resistance to loss of hydraulic conductivity. Next, we narrowed our focus to establish a genetic basis of internode anatomy variation with quantitative trait loci (QTL) analysis in the F2 progeny of a four-way outbred mapping population grown at a single site. Anatomical measurements of the F2 mapping population were utilized in QTL analysis to identify eight QTLs for six internode anatomy traits including cortical cell wall thickness, cortex radius, chlorenchyma radius, annulus area, epidermis cell count, and cortex-to-rind ratio. Candidate genes involved in various processes from cell cycle and hormone regulation to cell wall biosynthesis are present in the QTL intervals. Next we found that all biomass composition traits of lowland WBC vary significantly in clones grown across ten environments and 17 degrees of latitude. Lastly, we provide a detailed description of our hand sectioning method and present a 3D-printed microtome, “The Rapid-Tome”, specifically designed to effectively section hollow and tough materials such as switchgrass and woody stems up to 8 mm thick.
In total, this dissertation provides a valuable morphometric analysis of switchgrass internode anatomy and supports the long-term goal of enhancing biomass for biofuel production. This work identified variable internode anatomy traits that impact biomass digestibility and provide evidence that internode anatomy is an important factor of biomass tissue characteristics. This work shows that internode anatomy variation across environments shows potential to match genotype to specific environments to optimize internode anatomy for biomass conversion efficiency into biofuels. Furthermore, the QTL and candidate genes identified provide guidance for selectively breeding favorable internode anatomy phenotypes and presents a genetic basis for future genetic engineering of biofuel production-relevant traits
Processing of texting-while-driving narratives and attribution of responsibility to the perpetrator: the moderating effect of need to believe in a just world, situational similarity and the mediating effect of internal, external locus of control and sympathy
Get PDFTexting while driving is a dangerous form of distracted driving that causes injuries and fatalities every year. Combined efforts, such as legislation, enforcement, social norms, and education, were recommended to aware people about the consequences of texting while driving. However, there was insufficient research on how participants perceived the awareness campaign narratives describing the adverse effects of the drivers involved in texting-while-driving crashes. Thus, this study aimed to examine the texting-while-driving narrative campaigns on participants’ assignment of responsibility, punishment, attitudes, and driver traits to the responsible driver and behavioral intention not to text while driving. In addition, the study examined situational similarities between the participants and the perpetrator (and the victim) and the need to believe in a just world construct. The study employed a 2 (severity of outcome: severe vs. mild) x 2 (narrative types: endangering- self vs. endangering- others) x 2 (message replication) mixed factorial design. The severity of the outcome directly affected assigning punishment to the perpetrator, having negative attitudes toward the perpetrator and positive attitudes toward the victim. Endangering-others narratives directly affected assigning responsibility, punishment, less positive driver traits to the perpetrator, and having positive attitudes toward the victim. In the severe accident outcome, low situational similarities with the perpetrator decreased audiences’ behavioral intention to text while driving. The findings of this study will help design effective texting-while-driving campaigns. Theoretically, the findings of this study advance the application of defensive attribution theory (DAT), modified defensive attribution theory, the need to believe in a just world, and the rational decision stage model in a texting-while-driving scenario