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 55 for “"nitrogen oxides (NOx)"”.
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Exploring the Mechanistic Landscape of Nitric Oxide Oxidation and Ammonia Selective Catalytic Reduction of Nitric Oxide on Cu-Zeolites via Kinetic and Spectroscopic Characterization
… stringent regulations to reduce emissions of nitrogen oxides (NOx) from exhausts of heavy-duty diesel engines has set the stage to delve into a detailed investigation of engine after-treatment catalysts in order to understand the chemistry during their operation and design the next generation …
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Emission Measurement of Air Pollutants from CNG-gasoline Bi-fuel Vehicles
… study was performed for the EFs of carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx) for each operating condition when the vehicles using gasoline or compressed NG (CNG) as fuel.
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Observations of Aromatic Oxidation Products in Southeast Asia
… organic compounds (VOCs) in the presence of nitrogen oxides (NOx). PBzN, a key compound in this research, is primarily produced through the oxidation of benzaldehyde, which can originate from direct emission or from oxidation of species such as toluene and styrene. The study predicts PBzN …
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Plasmoid Vortex System Retrofit a Sustainability and Efficiency Study on Internal Combustion Engines
… as heat and exhaust waste, including carbon monoxide (CO), carbon dioxide (CO₂), hydrocarbons (HC), and nitrogen oxides (NOx). This inefficiency contributes to global carbon emissions, with transportation accounting for approximately 29% of U.S. greenhouse gases in 2021 [1]. As regulatory …
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Exposure to air pollution during pregnancy and health risks for mother and child
… For all outcomes air pollution was assessed as nitrogen oxides (NOx) and traffic exposure. For T1D we also assessed the association with exposures to ozone. We did not find any consistent associations between air pollution and birth outcomes, whereas an increased prevalence of gestational …
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Examining Transportation of Natural Gas Exploration Emissions in the High Plains Region Using the Wrf-Chem Model
… production relies on chemical reactions between nitrogen oxides (NOX) and volatile organic compounds (VOCs). Natural gas production is responsible for the production of both of these chemicals: heavy machinery in extracting processes generates nitrogen oxides and equipment leaks allow VOCs to …
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CHARACTERIZATION OF AIR POLLUTION AND AIR QUALITY USING INNOVATIVE SAMPLING METHODS AND ANALYTICAL TECHNIQUES FOR REGULATED AND NON-REGULATED POLLUTANTS
… as particulate matter (PM), ozone (O3), carbon monoxide (CO), and nitrogen oxides (NOx). Despite advancements in air quality regulations, many pollutants remain unregulated, both outdoors and indoors. Additionally, several sources of air pollution continue to be unmonitored, with their impacts on …
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Combustion and pollutant characteristics of IC engines fueled with hydrogen and diesel/hydrogen mixtures using 3D computations with detailed chemical kinetics
… 29 steps of hydrogen oxidation with additional nitrogen oxidation reactions were also employed. Formation rates of nitrogen oxides (NOx) within the engine were accurately predicted using the extended Zeldovich mechanism with parameters adjusted for a carbon-free fuel. The computational results …
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Life Cycle Analysis of a Ceramic Three-Way Catalytic Converter
… converter. Pollutants examined are carbon monoxide (CO), carbon dioxide (CO2), hydrocarbons (HC), and nitrogen oxides (NOx). The main finding is that even considering materials and processing, a catalytic converter decreases the CO, HC and NOx pollutant emissions. The CO2 emissions are …
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Predicting the behavior of a lean-burn hydrogen-enhanced engine concept
… combustion temperatures inhibit formation of nitrogen oxides (NOx), while reduced intake manifold throttling minimizes pumping losses leading to higher efficiency. These benefits are offset by the reduced combustion speed of lean mixtures, which can lead to high cycle-to-cycle variation and …
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Investigations on the pollutant emissions of gasoline direct injection engines during cold-start
… disproportionate share of the hydrocarbons (HC), nitrogen oxides (NOx) and particulate matter (PM) emitted over the certification cycle. Understanding the sources of the pollutants during this stage is necessary for the further market penetration of GDI under the constraint of tighter emission …
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CO and Hydrocarbon Oxidation on PD/Ceria-Zirconia/Alumina Three-Way Catalysts
… and reduce tailpipe emissions of carbon monoxide (CO), hydrocarbons (HCs), and nitrogen oxides (NOx) by converting these harmful and undesirable species to CO2, H2O, and N2. The oxidation behavior of CO and model hydrocarbons (propylene, acetylene, and ethylene) and performance of model …
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LARGE EDDY SIMULATION OF TURBULENT HYDROGEN FLAMES
… differential diffusion effects, and increased nitrogen oxides (NOx) emissions. These issues are particularly critical in lean premixed conditions, which are commonly used to limit emissions but lead to complex turbulence-chemistry interactions. This dissertation investigates turbulent hydrogen …
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Surface and microstructural properties of photocatalytic cements for pavement applications
… the environment by reacting with harmful nitrogen oxides (NOx) and removing them from the near-road environment. Photocatalytic FFC mixes were prepared in the laboratory to verify feasibility of field application and to characterize how mixture and microstructural properties and …
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Health impacts from urban air pollution in China : the burden to the economy and the benefits of policy
… matter (PM 10), sulfur dioxide (S02) and nitrogen oxides (NOx) were evaluated for 1970 to 2000, based on a set of epidemiological estimates of the effects of exposure to these pollutants. The estimated GDP impact to the Chinese economy of pollution levels above the WHO's recommended …
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Air quality analysis of nitrogen oxides and relationships with ozone pollution
… in the air 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 …
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Summertime ozone pollution in China: Observations and Simulations
… involves the photochemical reactions between nitrogen oxides (NOX = NO + NO2) and volatile organic compounds (VOCs). China is experiencing high levels of ozone due to high precursor emissions in association with rapid urbanization and industrialization in past decades. In this fast-changing …
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A study of droplet velocity and diameter measurements in a reacting diesel spray produced by a flow-blurring injector
… is important to obtain lower emissions of nitrogen oxides (NOx), carbon monoxide (CO), unburned hydrocarbons (UHCs), and soot particles. Thus, understanding spray characteristics is essential for determining how fuel and air mix with each other and subsequently combustion takes place. In …
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Modeling nighttime chemistry with WRF/chem: sensitivity to vertical resolution and boundary layer parameterization
… nitrate depend critically on the budget of nitrogen oxides (NOx). The NOx budget in turn is tied to the nocturnal N2O5 hydrolysis reaction, which takes place in the aqueous phase of aerosols. Through this reaction, NOx is removed from the atmosphere and HNO3 is formed, which then partitions …
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