Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 114 for “"Atmospheric carbon dioxide"”.
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Studies on the Conversion of Atmospheric Carbon Dioxide to Methanol
… the fundamentals and applications of converting atmospheric CO₂ to methanol (MeOH), covering catalysts to support the selective synthesis of MeOH and approaches to interface intermittent renewable power with the production of methanol. For thermochemical hydrogenation of CO₂ to methanol, …
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Trends in atmospheric carbon dioxide over the last ten to fifteen years
… Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1994.
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Effects of elevated atmospheric carbon dioxide concentration and drought on soybean leaf photosynthesis
… plots to study effects of drought and atmospheric CO$\sb2$ enrichment on leaf gas exchange. Midday depressions in net leaf photosynthetic CO$\sb2$ exchange rates (Pn) were found in drought-stressed plants and the diurnal changes were mostly stomatal regulated, although accumulated …
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Intraspecific, Interspecific, and Seasonal Variation in Acclimation of Photosynthesis to Rising Atmospheric Carbon Dioxide Concentration
This thesis aims to explain how species, genotype, developmental stage, and environmental factors that alter sink demand for carbohydrate influence acclimation of photosynthesis to elevated [CO2]. Variation in acclimation was addressed using meta-analytical techniques and three open-air CO 2 …
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Characterization of the impacts of the physiological response of vegetation to increasing levels of atmospheric carbon dioxide
Increasing atmospheric carbon dioxide (CO2) directly affects plant physiology. Using a coupled land-atmosphere model, multiple simulations have been conducted to examine the impact of the physiological response of vegetation to varying levels of CO2 near the leaf surface. Results showed that the …
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Analysis of microbes in Greenland ice cores from periods of high and low atmospheric carbon dioxide levels
… During the past 400,000 years, fluctuations in atmospheric carbon dioxide levels have directly coincided with temperature fluctuations. Three ice core sections from Byrd Station, Antarctica (80° 1’ S, 119° 31’ W) and three ice core sections from GISP 2D (Greenland Ice Sheet Project, core 2D; 72o …
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Elevated Atmospheric Carbon Dioxide and Ozone Concentrations Alter Leaf Area Index Through Changes in Leaf Production and Expansion
This research has shown that although elevated [CO2] increased LAI in aspen and soybean, the mechanisms for the change differed between the species. Leaf number was increased by elevated [CO2] in aspen, whereas individual leaf size was increased in soybean. Aspen and soybean had similar responses …
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The role of biological production in pleistocene atmospheric carbon dioxide variations and the nitrogen isotope dynamics of the southern ocean
… a cause of glacial/interglacial variations in atmospheric carbon dioxide. The hypotheses addressed involve changes in low and high-latitude biological export production. A modelling exercise demonstrates that the paleoceanographic record of calcite preservation places constraints on …
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The use of stomatal frequency from three Australian evergreen tree species as a proxy indicator of atmospheric carbon dioxide concentration
Increasing atmospheric carbon dioxide concentration ([CO2]) is the main contributing factor to anthropogenically derived global climate change. The impact of climate change upon terrestrial ecosystems is still uncertain. If information can be obtained on how past fluctuations in [CO2] and …
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The role of biological production in pleistocene atmospheric carbon dioxide variations and the nitrogen isotope dynamics of the southern ocean
… Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1997.
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Effects of Increased Atmospheric Carbon Dioxide Levels on Tobacco Mosaic Virus and Root-Knot Nematodes in Genetically Resistant and Susceptible Tomato Plants
<p>Rising atmospheric carbon dioxide (CO<sub>2</sub>) may affect plant/pathogen interactions. This study focused on the effects of elevated CO<sub>2</sub> on Root-Knot Nematode (<em>Meloidogyne arenaria</em>) and Tobacco Mosaic Virus (TMV) infection in genetically resistant versus susceptible …
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The effects of elevated atmospheric CO2 on below ground processes in fynbos and C4 ecosystems
This thesis investigated ways in which elevated atmospheric carbon dioxide (CO2) concentrations influence the plant: soil interface and soil biological processes. The studies focused on microbial populations associated with the plant rhizosphere, and how these responses could feed into changes in …
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Effect of Increased Carbon Dioxide Levels on Urushiol Production in Toxicodendron radicans and Toxicodendron toxicarium
… to increased greenhouse gases, one of which is carbon dioxide. An increase in atmospheric carbon dioxide has been shown to stimulate higher rates of plant productivity, including the production of plant toxins like urushiol. Urushiol, a secondary plant compound produced in members of the …
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Development of an econo-energy model and an introduction to a carbon and climate model for use in a nuclear energy analysis
… Currently, we feed our power needs with mostly carbon-based energy sources, which have an appreciable effect on the global climate. To continue advancing, society must develop alternative, low-carbon methods for energy production with both nuclear and renewable sources being complementary …
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Soil Carbon Assessment: Confronting Climate Change on the Farm
… in negative emissions in order to stabilize atmospheric carbon dioxide concentrations and prevent catastrophic changes in climate. Soil carbon sequestration on arable lands is a negative emissions technology with high climate change mitigation potential that also confers agronomic …
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Adaptive Oxygen Production of the Mars Oxygen ISRU Experiment (MOXIE) though Feedback Control of Pressure Sensor 4
… Mars by means of Solid Oxide Electrolysis from atmospheric Carbon Dioxide. This work builds on the mission goals of MOXIE, which runs only intermittently and with much manual planning for each run, to develop control algorithms that will lay the foundation for fully autonomous and continuous …
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On the role of the Southern Ocean in the global carbon cycle and atmospheric CO2 change
… mechanism(s) responsible for natural changes in atmospheric CO2 concentration. It is becoming clear that the Southern Ocean overturning circulation plays an important role in the global carbon cycle because altered communication between the atmosphere and abyss in the Southern Ocean is relatively …
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Modelling vegetation dynamics and their feedbacks over Southern Africa in response to climate change forcing
… is growing in light of the increasing atmospheric carbon dioxide concentrations and the change in climate associated with these increases. These linkages are analysed over southern Africa with the use of sophisticated computer models of the climate and vegetation. The models are used to …
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Effects of Elevated Atmospheric CO2 on Root Growth, Turnover and Decomposition in a Scrub Oak Ecosystem
<p>Atmospheric carbon dioxide levels are increasing and predicted to double this century. The implications of this rise on vegetation structure and function are not well understood. Measurement of root growth response to elevated atmospheric carbon dioxide is critical to understanding soil carbon …
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