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.
Results
Showing 1 to 20 of 119 for “"NOx emissions"”.
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An Environmental Cost Basis for Regulating Aviation NOx Emissions/
… and setting commercial aircraft NO[subscript x] emissions standards since 1981 Each of the historical standards has been more stringent than the previous and, when implemented, requires newly certified engines to produce less NO[subscript x] per unit rated thrust Each iteration has been defined …
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Real-time measurement of oxides of nitrogen from heavy-duty diesel engines
New emissions regulations and performance requirements imposed on modern diesel engines encourage the development of improved tools for emissions measurements. This study investigated one of the improved tools for NOx emissions measurement. Objectives of this thesis included measurement, comparison …
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Design and Evaluation of a Marine Scrubber System
Increasingly stringent oxides of nitrogen (NOX) emissions regulations for diesel marine engines are resulting in the development of newer engines with inherent NOX emissions reduction technologies. With typical useful service lives over 20 years, older diesel marine engines are producing …
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Reducing the contribution of the power sector to ground-level ozone pollution : an assessment of time-differentiated pricing of nitrogen oxide emissions
Nitrogen oxide (NOx) is a prevalent air pollutant across the United States and a requisite precursor for tropospheric (ground-level) ozone formation. Both pollutants significantly impact human health and welfare, so National Ambient Air Quality Standards (NAAQS) have been established for each. As …
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Computational Modeling of Nitrogen Oxide Emissions From Biodiesel Combustion Based on Accurate Fuel Properties
… was applied to evaluate strategies for reducing NOx emissions from biodiesel combustion. The results indicated that increasing spray cone angle, retarding start of injection, applying exhaust gas recirculation (EGR) and charge air cooling were all effective in reducing NOx emissions from …
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Climate impact of aviation NOx̳ emissions : radiative forcing, temperature, and temporal heterogeneity
Aviation NOx emissions are byproducts of combustion in the presence of molecular nitrogen. In the upper troposphere, NOx emissions result in the formation of O₃ but also reduce the lifetime of CH4 , causing an indirect reduction in the formation of O₃. Meta studies by Lee et al. and Prather et al. …
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Physics-Based Artificial Intelligence Models for Vehicle Emissions Prediction
… understanding of complex physical phenomena like emissions formation during combustion. In this thesis, a physics-based artificial intelligence framework is developed to predict and analyze trends in engine-out NOx emissions of diesel and diesel-hybrid heavy-duty vehicles. This framework differs …
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Autoignition and emission characteristics of gaseous fuel direct-injection compression-ignition combustion
… from impaired efficiency and high unburned fuel emissions. Natural gas direct-injection engines offer the potential of diesel-like efficiencies, but require further research. To improve understanding of the autoignition and emission characteristics of natural gas direct-injection …
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Air quality analysis of nitrogen oxides and relationships with ozone pollution
… in high enough concentrations. Nitrogen oxides (NOx), especially nitrogen dioxide (NO₂), are increasingly of concern due to the environmental and health problems they cause. This reviews the recent literature on the reasons and impacts of NOx pollution as well as ozone pollution related to NOx …
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Investigation of combustion and emission characteristics of a diesel engine fueled with butanol-diesel blends
… from raw exhaust gas, while the change in NOx emissions varies depending on the butanol content and engine operating conditions. Increasing EGR ratio and retarding injection timing are effective approaches to reduce NOx emissions from combustion of butanol-diesel blends. But the engine …
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Low-Temperature Combustion in a Small-Bore High-Speed Direct Injection Optically Accessible Diesel Engine
… a faster soot oxidation rate. The increased NOx emissions of bio-diesel fuels were greatly reduced by employing the low temperature combustion mode. Results showed that low temperature combustion with bio-diesel fuels could simultaneously reduce soot and NOx emissions.
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Employment of Multi-Source Satellite-Based Observations in Air Quality Modeling over Asia
… estimates of East Asia’s nitrogen oxides (NOx) and primary particulate matter (PM) emissions to improve model accuracy in simulating aerosol optical depth (AOD), using nitrogen dioxide (NO2) columns and AOD data from the TROPOspheric Monitoring Instrument (TROPOMI), Advanced Himawari Imager …
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Effects of high levels of steam addition on NOx̳ reduction in laminar opposed flow diffusion flames
A "leveling off" trend in NOx emissions with high amounts of steam addition has been observed in industrial gas turbine diffusion flame combustors. Experiments were performed to try to reproduce this trend in a laminar, opposed flow diffusion flame burner. Experiments were performed with Cli4, …
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Modeling aviation's global emissions, uncertainty analysis, and applications to policy
(cont.) fuel burn results below 3000 ft. For emissions, the emissions indices were the most influential uncertainties for the variance in model outputs. By employing the model, this thesis examined three policy options for mitigating aviation emissions. More stringent engine certification …
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In Cylinder NOx Control Technologies for Marine Diesel Engines
… their potential in order to reach the IMO Tier 3 NOx emissions target. By means of extreme Miller cycles, with Early Intake Valve Closures (EIVC up to 100 crank angle degrees before BDC), a shorter compression stroke and lower charge temperatures inside the cylinder can be achieved and thanks to …
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Effects of split injection and exhaust gas recirculation strategies on combustion and emissions characteristics in a modern V6 diesel engine
… (TME)-diesel blends, in order to meet future emissions legislation. One of the main objectives of this research is to improve fuel consumption whilst minimising engine emissions through the combined effects of injection strategy (fuel injection pressure, dwell period, pilot fuel quantity) and …
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The combustion and emissions performance of fuel blends in modern combustion systems
The combustion and emissions performance of fuel blends in modern combustion systems has been investigated with the intention of reducing emissions, improving efficiency and assessing the suitability of future automotive fuels. The combustion systems used in this study include Homogeneous Charge …
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Adjoint sensitivity analysis of the intercontinental impacts of aviation emissions on air quality and health
… to particulate matter caused by aircraft emissions. Unlike previous studies that focus on the regional impacts from the aircraft emissions below 3,000 feet, this thesis studies the impact from emissions at all altitudes and across continents on increasing particulates in a receptor region, …
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Optimizing conventional combustion and implementing low-temperature combustion of biodiesel in a common-rail high-speed direct-injection engine
… modified and have significant effects on engine emissions. Tests were run at low to moderate engine load at different engine speeds. It was found that with the ECM’s default settings, higher blends of biodiesel tended to result in higher NOx emissions and lower soot emissions, in line with …
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Fuel flexible clean combustion of liquid fuels by a novel twin fluid atomization
… able to burn glycerol cleanly, with low CO and NOx emissions. At industrial test site, combustion experiments with 40% methane and 60% glycerol resulted in stable flame. Next, effect of operating pressure on flame characteristics and injector pressure drop is experimentally investigated with …
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