59,359 research outputs found
Gas phase bond dissociation enthalpies and enthalpies of isomerization/reaction for small hydrocarbon combustion related compounds between 300 and 1500 K: A comparison of Gaussian-4 (G4) theoretical values against experimental data
Gas phase calculations at 1 atmosphere pressure between 300 and 1500 K at 200 K intervals were conducted using the Gaussian-4 (G4) composite method level of theory on a representative set of reactions having broad relevance in hydrocarbon combustion chemistry. Reasonable agreement between the experimental and theoretical data was obtained across the temperature range under consideration for all bond dissociation enthalpies, isomerization enthalpies, and enthalpies of reaction. For some reaction schemes, chemical accuracy for the theoretical method was maintained over the complete temperature range, whereas other systems displayed up to several kcal mol^-1^ deviations from experimental data. The direction of signed errors generally increased as the temperature was raised, and no general error trends were related to molecular size or reaction class
Projected Climate Change Impacts on Grape Growing in the Okanagan Valley, British Columbia, Canada
A statistical analysis was conducted on long-term climate records in the Okanagan Valley wine grape growing region of British Columbia, Canada. No observable trends for average annual temperatures were found in the region. Analyses of monthly mean and extreme temperatures show wide spatial and temporal heterogeneity, indicating that future studies using downscaling of global climate models for this region will require resolutions on the order of several kilometers. Mean winter temperatures are increasing throughout the valley, and extreme minimum temperatures are also increasing during the winter at the central and northern sites which have historically presented the most risk of winter damage to grapevines. Only the most southern and northern sub-regions are expected to see significant changes in their heat unit accumulations during the growing season. Over the coming century, the southern end of the valley will likely move from Winkler heat unit region 1 to 2. All regions of the Okanagan will continue to have latitude-temperature indices among the lowest of the world's fine table wine producing regions over the coming century. Growing season and dormant season average temperatures are expected to change by only a modest amount by 2100. Current climate maturity groupings for ripening grape varieties will likely stay constant at cool (central and southern areas) and intermediate (south-central) for all sites except Osoyoos (south). The climate trendings at Osoyoos suggest it will transition from an intermediate to a warm grouping by about 2050. The early to mid-season ripening capacity of the region may improve due to climate changes, but there is a risk of the asymmetric late season increases in minimum daily temperatures lowering the daily temperature range at some sites, possibly leading to difficulties in maintaining a balanced between sugar and sensory profiles as wine grapes approach maturity. The projected warming at the southern end of the valley should favor improved and increased Merlot production, will require Chardonnay production to shift northwards, and will allow growing of warmer climate wine grape varieties currently inaccessible because of low winter temperatures and a lack of growing season heat units. Increasing winter temperatures throughout the region are expected to result in increased risk of pests such as Pierce’s disease
Congener-Specific Numbering Systems for the Environmentally Relevant C4 through C8 Perfluorinated Homologue Groups of Alkyl Sulfonates, Carboxylates, Telomer Alcohols and Acids, and Their Derivatives
We introduce a congener-specific numbering system for the C4 through C8 perfluorinated homologue groups of alkyl sulfonates, carboxylates, telomer alcohols and acids, and their derivatives. Increasing length of the carbon chain beyond C3 leads to a corresponding rapid increase in the number of potential isomers (C4 =4, C5 =8, C6 =17, C7 =39, and C8 =89 congeners). There is a need for clear and unambiguous chemical shorthand to ensure accuracy and consistency in the future perfluorinated alkyl substance (PFA) literature, and to correct previous misconceptions that may have restricted research efforts into developing full-congener PFA analysis. If adopted by the research community, introduction of a numbering system at this relatively early stage of investigations into the congener-specific analysis, environmental behavior, and toxicology of PFAs would not require an arduous and difficult reassignment of historical structures and naming conventions presented in the prior art. Many PFA congeners are chiral, necessitating a consideration of their enantiospecific environmental behavior and toxicology
Cs the Day: The Trading Card Game
In many ways, Cs the Day: The Card Game is an ode both to academia, which is imperfect but can at times be wonderful, and to my personal passion and research interest, which has helped me to find a place within this profession. It is also, as is discussed in more detail below, an extension of an existing game, and as such embodies many of the same goals and principles of that game. Thus, designing Cs the Day: The Card Game required careful attention to how the mechanics and narrative reflect both the profession and the original game. There are certainly substantial critiques to be made about academia, and in particular the tenure process. Indeed, Way Jengâs âHow I Learned to Love Despair: Using Simulation Video Games for Advocacy and Change,â a tycoon-esque simulation game addressing the use of contingent faculty in English departments, does an excellent job of modeling how games can be used to critique academia. That game places players in the role of an English department chair and asks them to balance faculty loads (both service and teaching related), the department budget, and university goals. By doing so, Jeng creates an open space for academics to play with this system, in a way that encourages further critique and engagement with the ethics of dependance on contingent faculty. Thus, the play of âDespairâ is transformative in that it allows us to âsee values and practice them and challenge them so they become more than mindless habitsâ (Sicart 5)
Writing In and Around Video Games
This undergraduate course uses video games as a lens through which to explore the infinitely broader topic of digital rhetoric. Students encounter games in several different ways: as texts to analyze, raw material for video compositions, systems to create and explore. Key topics include genre conventions and constraints, audience, procedural rhetoric, interface design, and convergence culture
Playing with Play: Machinima in the Classroom
âSo, machinima is really a genre, and not a medium?â
The students in my Digital Media and Rhetoric course are grappling with both how to define machinima and how to evaluate whether one is âgoodâ or not. I frustrate them by refusing to provide a definitive answer to this and other similar questions they have asked about the form. This intentional frustration continues as, after watching a few examples they ask me what grade I would give those machinima, if they were turned in for this assignment. Rather than providing a simple answer I redirect, asking them what criteria they would use to evaluate machinima and how the examples weâve seen in class stand up to this scrutiny. At the beginning of this particular unit, when I announced that we wouldnât be writing another research paper, they were exuberant. Now, however, the complexity of the task before them is slowly unveiling itself. While a majority of these students are gamers, few of them have experience in video production. None of them have previously looked at fan culture as a source of meaning and knowledge production. We are in unfamiliar territory, and they are getting restless
Carbon Dioxide Splitting: A Summary of the Peer-Reviewed Scientific Literature
Increasing concentrations of carbon dioxide (CO2) in the atmosphere have stimulated significant global research and development efforts regarding the reduction in CO2 emissions from all point and non-point sources. In addition to technologies that do not use carbon feedstocks or which capture and "permanently" store CO2 (i.e., sequestration), there is considerable worldwide interest among the academic, industrial, and government communities regarding methods for dissociating waste stream carbon dioxide molecules into their constituent carbon and oxygen ("CO2 splitting") atoms as a final "end-of-pipe" treatment option. The splitting of carbon dioxide has also been actively discussed and researched in the space exploration and extraterrestrial colonization programs for several decades. This document summarizes the peer-reviewed open source scientific literature regarding carbon dioxide splitting
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