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- All Subjects: Carbon Sequestration
- All Subjects: Education
- Resource Type: Text
Description
Increasing concentrations of carbon dioxide in the atmosphere will inevitably lead to long-term changes in climate that can have serious consequences. Controlling anthropogenic emission of carbon dioxide into the atmosphere, however, represents a significant technological challenge. Various chemical approaches have been suggested, perhaps the most promising of these is based on electrochemical trapping of carbon dioxide using pyridine and derivatives. Optimization of this process requires a detailed understanding of the mechanisms of the reactions of reduced pyridines with carbon dioxide, which are not currently well known. This thesis describes a detailed mechanistic study of the nucleophilic and Bronsted basic properties of the radical anion of bipyridine as a model pyridine derivative, formed by one-electron reduction, with particular emphasis on the reactions with carbon dioxide. A time-resolved spectroscopic method was used to characterize the key intermediates and determine the kinetics of the reactions of the radical anion and its protonated radical form. Using a pulsed nanosecond laser, the bipyridine radical anion could be generated in-situ in less than 100 ns, which allows fast reactions to be monitored in real time. The bipyridine radical anion was found to be a very powerful one-electron donor, Bronsted base and nucleophile. It reacts by addition to the C=O bonds of ketones with a bimolecular rate constant around 1* 107 M-1 s-1. These are among the fastest nucleophilic additions that have been reported in literature. Temperature dependence studies demonstrate very low activation energies and large Arrhenius pre-exponential parameters, consistent with very high reactivity. The kinetics of E2 elimination, where the radical anion acts as a base, and SN2 substitution, where the radical anion acts as a nucleophile, are also characterized by large bimolecular rate constants in the range ca. 106 - 107 M-1 s-1. The pKa of the bipyridine radical anion was measured using a kinetic method and analysis of the data using a Marcus theory model for proton transfer. The bipyridine radical anion is found to have a pKa of 40±5 in DMSO. The reorganization energy for the proton transfer reaction was found to be 70±5 kJ/mol. The bipyridine radical anion was found to react very rapidly with carbon dioxide, with a bimolecular rate constant of 1* 108 M-1 s-1 and a small activation energy, whereas the protonated radical reacted with carbon dioxide with a rate constant that was too small to measure. The kinetic and thermodynamic data obtained in this work can be used to understand the mechanisms of the reactions of pyridines with carbon dioxide under reducing conditions.
ContributorsRanjan, Rajeev (Author) / Gould, Ian R (Thesis advisor) / Buttry, Daniel A (Thesis advisor) / Yarger, Jeff (Committee member) / Seo, Dong-Kyun (Committee member) / Arizona State University (Publisher)
Created2015
Description
Distance and Blended education have been studied and applied in many disciplines but there has been limited use and assessment of these learning modes for design studios. The Coronavirus Disease (COVID-19) pandemic has forced education delivery methods in the United States to become more online/hybrid in the 2020 school year without much preparation. As schools slowly shift to post-pandemic teaching modes, it is necessary to examine and evaluate what was learned during the pandemic online environment for design education. Previous studies have examined the effectiveness of online delivery of design education by virtual design studios using advanced digital technologies and equipment on a variety of platforms to teach specific design skills. In this study, the researcher uses semi-structured interviews of design educators and a survey of design students to examine their experience with their online learning environment during the 2020 school year. The qualitative and quantitative results of the study shed light on the challenges of online design studio learning during the pandemic and revealed opportunities for improving future design studio education. Lack of social interactions during the pandemic online learning impacted students’ motivation. The use of digital technologies improved communication efficiency, but there is also ineffective communication that negatively affected peer interaction and learning, which in turn affected student learning outcomes and learning satisfaction compared to in-person design studios. The results also revealed openings to promote fully online design education, with studio courses reconfigured using the Technological Pedagogical and Content Knowledge (TPACK) framework and with properly trained design instructors. This hybrid learning environment would lead to students receiving an optimal learning experience that benefits from the advantages of in-person instructions along with the efficiency of digital technology-based learning platforms. Keywords: online design education, hybrid teaching, virtual design studios, COVID-19 pandemic, TPACK.
ContributorsYuan, Jinlong (Author) / Brooks, Kenneth (Thesis advisor) / Hall, Allison (Committee member) / Brunner, Lori (Committee member) / Perkins, Samantha (Committee member) / Arizona State University (Publisher)
Created2022
Description
The profession known as industrial design is undergoing a transformation. Design thinking and strategy are replacing form giving and styling. Critics are calling for curricular reform to meet the changing needs of practice, yet surprisingly little knowledge is available about how and why design teachers do what they do. In an effort to frame the problem of (re)designing design education, this study provides a framework for understanding the pedagogical beliefs and preferences of design students and educators utilizing Bruner’s four folk pedagogies. This study also provides evidence that the practices of industrial design teachers exhibit what Cross (2006) has described as ‘designerly ways of knowing.’
ContributorsChristensen, Tamara Fawn (Author) / Nocek, Adam (Thesis advisor) / Brooks, Kenneth (Thesis advisor) / Heywood, William (Committee member) / Henriksen, Danah (Committee member) / Mishra, Punya (Committee member) / Arizona State University (Publisher)
Created2020
Description
Despite public demand for climate change mitigation and natural open space conservancy, existing political and design efforts are only beginning to address the declining efficacy of the biotic carbon pool (C-pool) to sequester carbon. Advances in understanding of biogeochemical processes have provided methods for estimating carbon embodied in natural open spaces and enhancing carbon sequestration efficacy. In this study, the benefits of carbon embodied in dryland open spaces are determined by estimating carbon flux and analyzing ecological, social, and economic benefits provided by sequestered carbon. Understanding the ecological processes and derived benefits of carbon exchange in dryland open spaces will provide insight into enhancing carbon sequestration efficacy. Open space carbon is estimated by calculating the amount of carbon sequestration (estimated in Mg C / ha / y) in dryland open space C-pools. Carbon sequestration in dryland open spaces can be summarized in five open space typologies: hydric, mesic, aridic, biomass for energy agriculture, and traditional agriculture. Hydric (wetland) systems receive a significant amount of moisture; mesic (riparian) systems receive a moderate amount of moisture; and aridic (dry) systems receive low amounts of moisture. Biomass for energy production (perennial biomass) and traditional agriculture (annual / traditional biomass) can be more effective carbon sinks if managed appropriately. Impacts of design interventions to the carbon capacity of dryland open space systems are calculated by estimating carbon exchange in existing open space (base case) compared to projections of carbon sequestered in a modified system (prototype design). A demonstration project at the Lower San Pedro River Watershed highlights the potential for enhancing carbon sequestration. The site-scale demonstration project takes into account a number of limiting factors and opportunities including: availability of water and ability to manipulate its course, existing and potential vegetation, soil types and use of carbon additives, and land-use (particularly agriculture). Specific design challenges to overcome included: restoring perennial water to the Lower San Pedro River, reestablishing hydric and mesic systems, linking fragmented vegetation, and establishing agricultural systems that provide economic opportunities and act as carbon sinks. The prototype design showed enhancing carbon sequestration efficacy by 128-133% is possible with conservative design interventions.
ContributorsHuck, Erick (Author) / Cook, Edward (Thesis advisor) / Green, Douglas (Committee member) / Brooks, Kenneth (Committee member) / Montemayor, Gabriel (Committee member) / Arizona State University (Publisher)
Created2012