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 39 for “"Gas Transfer"”.
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Visualization of Near-Surface Flow Patterns for Air-Water Gas Transfer
… in the water body and a controlled influx of HCl gas. Trace amounts of precipitate are made visible by scattering laser light. Using the new method, the influence of wind induced turbulences at the water interface can be investigated with previously unachieved sensitivity. Illumination of the wavy …
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QUANTITATIVE VISUALIZATION OF CARBON DIOXIDE GAS TRANSFER AT A TURBULENT FREE SURFACE
We study the aqueous-phase side of the transfer of carbon dioxide gas across an air-water interface. Quantitative imaging techniques are used to directly visualize the physical processes which determine the average gas transfer rate. The interface is a free surface in the absence of mean shear, …
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Spirometric and gas transfer measurements among normal adult South African men : an investigation into anthropoemtric, socio-economic, racial and environmental factors influencing lung function
An investigation into anthropocentric, socio-economic, racial and environmental factors influencing lung function. In modern clinical practice the data derived from pulmonary function tests are an integral part of the evaluation of pulmonary disease states. Such data may shed light on the nature of …
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A comparison of gas exchange models in the estimation of CO2 fluxes in the South Atlantic South of Africa for the summer season of 2008/2009
… of different relationships used in calculating gas transfer velocities. There is also a problem with the CO2 sink in the Southern Ocean being greatly underestimated. Data were collected underway using an autonomous pCO2 system during three separate relief cruises over the course of austral …
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A Comparison of Gas Exchange Models in the Estimation of CO2 Fluxes in the South Atlantic South of Africa for the Summer Season of 2008/2009
… of different relationships used in calculating gas transfer velocities. There is also a problem with the CO2 sink in the Southern Ocean being greatly underestimated. Data were collected underway using an autonomous pCO2 system during three separate relief cruises over the course of austral …
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Free-surface turbulence and air-water gas exchange
… the physical mechanisms of air-water gas transfer through direct measurements of turbulence at the air--water interface. To enable this study, a new approach to the particle image velocimetry (PIV) technique is developed in order to quantify free-surface flows. Two aspects of this work …
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Production of biopolymer using a membrane-based bioreactor
Methane is a potent greenhouse gas produced from natural gas reservoirs, landfills, and anaerobic digesters. Some methanotrophic bacteria produce intracellular polyhydroxybutyrate (PHB) in the absence of nitrogen and presence of methane and oxygen. In this study, Colorado School of Mines (CSM) and …
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Modeling effects of U-tube aeration in recirculating aquaculture systems
… quality, and biological processes on oxygen transfer requirements. A computer model was developed to simulate multi-component gas transfer and biological respiration in a pilot scale recirculating aquaculture system employing an u-tube aerator. Gas transfer and/or biological respiration are …
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Measurement and parameterisation of the air-sea CO2 flux in high winds
… are large differences between existing gas transfer to wind speed relationships, particularly at high wind speeds, and there is significant uncertainty over the form (quadratic or cubic) of the relationship. From the 3938 direct CO2 flux measurements made onboard Polarfront, a …
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The role of genetic and environmental variation in the respiratory phenotype of alpha 1 antitrypsin deficiency
… Of four MMPs studied, association with gas transfer occurred in two. HLA-DQA1*0301 and HLA-DRB1*04 contributed significantly to gas transfer in regression models, and anti elastin antibodies were higher in HLA-DRB1*04 and HLA-DQA1*0301 homozygotes. Ozone levels contributed to the burden …
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Exacerbations, health status and sibling pair comparisons in severe Alpha-1-Antitrypsin Deficiency
… were associated with a decline in the gas transfer of the lung over time, but show no relationship to changes in forced expiratory volume in one second (FEV1). However, despite lung function decline, patients do not show a progressive loss in health status. Index patients have worse …
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The long-term respiratory health effects of the herbicide, paraquat, among Western Cape workers
… and confounding variables. Spirometry and gas transfer were measured and chest radiographs performed. Oxygen desaturation on exercise testing was by oximetry during a modified stage one exercise test. Results: No association was found between long-term paraquat exposure and reported …
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Identifying the dominant physical processes for mixing in full-scale raceway tanks
… can both promote vertical mixing and enhance gas transfer across the free surface of the growth medium. Experiments are performed in a full-scale open RWT at the University of Illinois, Urbana-Champaign, Ecohydraulics and Ecomorphodynamics Laboratory (EEL), in which the bed of the RWT is …
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Measurements of sub-surface bubble populations and the modelling of air-sea gas flux
… by breaking waves, play an important role in the transfer of gases between the Earth’s oceans and atmosphere and have been shown to increase the flux of gases during periods of heightened sea state. Having been<br/>formed, these bubble clouds evolve through the effects of buoyancy, gas exsolution …
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Modeling for anaerobic fixed-bed biofilm reactors
… from the equilibrium model to simulate the gas transfer process involved in biogas production. The equilibrium model well described the behavior of anaerobic fixed-bed biofilm reactors, which was verified in the experimental results. The non-equilibrium model showed that the contact area …
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Spatio-temporal slope measurement of short wind waves under the influence of surface films at the Heidelberg Aeolotron
… It is shown that, except for low wind speeds, gas transfer velocities across the air-sea boundary layer can be parametrized with the mean square slope of the waves, independent of the specific type of surfactant that is used.
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The relative roles of portal hypertension and of cirrhosis in the pathogenesis of pulmonary lesions associated with chronic liver disease
… and normal liver histology. Carbon monoxide gas transfer (TLCOsb) was less than 75% of predicted values in four patients from each group. One patient from each group had clinical and catheter confirmed evidence of pulmonary hypertension. Abnormal cardiorespiratory responses to exercise …
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Theoretical and numerical study of air entrainment and bubble size distribution in strong free-surface turbulent flow at large Froude and Weber number
… significant interactions and exchanges between gas and liquid, resulting in measurable air entrainment. Air entrainment influences a number of physical processes in the nature, including air-sea gas transfer, production of the sea-salt aerosol and scavenging of biological surfactant. The key …
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The biogeochemistry and residual mean circulation of the southern ocean
… in order to study the air-sea fluxes of trace gases and biological productivity and their potential changes over glacial-interglacial timescales. Mesoscale eddy transfers play a dominant role in the dynamical and tracer balances in the Antarctic Circumpolar Current, and the transport of tracers …
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Physical chemical processes and environmental impacts associated with home composting
… The focus of the work was climate relevant gaseous emissions, and developing and utilising a methodology for quantifying them. Experiments using 220L open bottomed home compost bins, alongside purpose built 200L composting reactors with airflow control were performed. A variety of composting …
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