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 23 for “"Carbon dioxide concentrations"”.
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Soil Carbon Assessment: Confronting Climate Change on the Farm
… 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 co-benefits, but …
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Experimental Study of the PVTX Properties in Part of the Ternary System H₂O-NaCl-CO₂
… properties in the system water-sodium chloride-carbon dioxide were determined experimentally for pressures between about 1 to 6 kbar, temperatures of 300° to 800°C, and fluid compositions up to 40 wt% NaCl and 20 mol% carbon dioxide, both relative to water. This was accomplished by using the …
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Modelling vegetation dynamics and their feedbacks over Southern Africa in response to climate change forcing
… 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 explore …
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A comparative study of the ventilatory responses of the golden hamster, Mesocricetus auratus and the laboratory rat, Rattus norvegicus, under hypercapnic and/or hypoxic gas mixtures
… to different ambient respiratory gas concentrations with those of the white rat (<i>Rattus norvegicus</i>). Total body plethysmography was used to measure tidal volume (V<sub>T</sub>), respiratory frequency (R<sub>f</sub>), and minute volume (V<sub>E</sub>). The respiratory gases had …
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Stand dynamics and gas exchange in loblolly pine and hardwood seedling stands: impact of elevated carbon dioxide, water stress and nutrient status
… southern United States. Rising atmospheric CO₂ concentrations over the next several decades could influence competitive interactions between these species. This research examined the effects of increased atmospheric CO₂ concentration in combination with the availability of other resources on …
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Induced technical change in computable general equilibrium models for climate-change policy analysis
… climate change focus on stabilizing atmospheric carbon dioxide concentrations by drastically reducing anthropogenic emissions of carbon. Such reductions require limiting the use of fossil fuels-which supply the bulk of energy to economic activity, and for which substitutes are lacking-which is …
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An analytical and experimental investigation of respiratory dynamics using P/D control and carbon dioxide feedback
… humoral mechanisms. Using the assumption that carbon dioxide concentrations in the arterial blood have the strongest effect, a control equation with proportional and derivative components based on this driver was evaluated. The methodology for the evaluation was to create a model of the …
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Mathematical Modeling of Carbon and Light-Limited Algal Biofilms
A mathematical model of carbon and light limitation in algal biofilms was developed based on well-established fundamental descriptions of chemical, physical, and biological processes. The model considers carbon dioxide utilization and production from photosynthesis and respiration, diffusion of …
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Municipal yard waste composting: process parameters, windrow gases, and leachate quality
… compost; 2) to investigate the oxygen (O₂), carbon dioxide (CO₂) and methane (CH₄) relationships in the composting yard waste; and 3) to quantify water quality parameters of the leachate from yard waste composting mixes. Mixes of 3 parts leaves/1 part grass, 2 parts woodchips/1 part grass, …
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The effect of soybean oil in starter diets on nursery air quality and performance of weanling pigs
… air quality was evaluated by measuring the concentrations of ammonia, carbon dioxide, settled dust, suspended particle size, and by microbiologically culturing air samples. Weekly performance data was also collected. ADG was unaffected by dietary treatment. ADFI was increased when soybean …
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Linking Carbon, Nitrogen, And Calcium Cycling In Northeastern U.S. Forests
Carbon (C), nitrogen (N), and calcium (Ca) cycling in forest ecosystems is controlled largely by the recycling of organic matter by biota and by the balance of new inputs and losses. In the northeastern U.S., the availability of these elements has been dramatically altered by human activities. Acid …
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Pre-industrial to 2000 ppm; soybean response to increasing CO2
Many studies addressing the effects of rising carbon dioxide concentrations ([CO2]) on agricultural crops have demonstrated the critical role that this gas has on plant physiology. It is now essential to assess the responses of our major crop systems to even higher [CO2] as these photosynthetic and …
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Orbital and Suborbital Climate Variability during the Pliocene Intensification of Northern Hemisphere Glaciation
… was accompanied by a decrease in atmospheric<br/>carbon dioxide concentrations and commenced around 3.5 million years ago. The climate<br/>forcing and response mechanisms involved in the iNHG are subjects of ongoing debate in the<br/>palaeoclimate literature. In this thesis, I reconstruct …
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Factors Affecting Nitrogen Fixation Rates in Termites (Isoptera: Rhinotermitidae: <i>Reticulitermes</i>) and Termite Nitrogen Contributions of Forest Ecosystems
… on nitrogenase activity, and low oxygen and high carbon dioxide atmospheres on termite nitrogenase activity, and the accuracy of mark-recapture studies to estimate termite population size.</p> <p>Termite nitrogen fixation rates were monitored monthly for 10 Reticulitermes Holmgren colonies from …
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Evaluating the influence of establishing pine forests and switchgrass fields on local and global climate
… the change has also altered climate through carbon emissions and changes in the surface energy balance. Consequently, maximizing both the provisioning and climate regulation services provided by terrestrial ecosystems is a grand challenge facing a growing global population living in a …
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Carbon fluxes of an extensive meadow and attempts for flux partitioning
In times of climate change and increasing carbon dioxide concentrations, three questions arise for ecosystem sciences: At first, which ecosystems can contribute to mitigate those processes? Secondly, how will ecosystems react on the changing conditions? And finally, is the performance of our …
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Monitoring and modelling diurnal and seasonal odour and gas emission profiles for swine grower/finisher rooms
… of odour and gas (ammonia, hydrogen sulphide, carbon dioxide) concentrations and emission rates (OGCER), which may result in great uncertainties in setback distance calculations. Thus, the purpose of this project was to monitor and model diurnal and seasonal OGCER from swine grower/finisher …
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Assessing the effects of genetic modifications on photosynthetic capacity in Nicotiana tabacum (tobacco) and Glycine max (soybean)
… carboxylase/oxygenase for carbon dioxide, one encodes a gene for expression of a bicarbonate transporter, and one overexpresses the native rubisco by 15%. Plants were phenotyped in an agricultural field trial and then in two controlled environment experiments. It was …
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Assessing the photosynthetic impact of inorganic carbon in symbiotic dinoflagellates in culture and in coral host complexes
Increased atmospheric carbon dioxide concentrations are causing warming of the Earth's atmosphere and having significant effects on the chemistry of the oceans. Disruption to seawater biochemistry is causing associated pH change known as ocean acidification and increased concentrations of dissolved …
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