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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Leveraging Weigh-In-Motion (WIM) Data to Estimate Link-Based Heavy-Duty Vehicle Emissions

Alwakiel, Heba Naguib 01 January 2011 (has links)
This research examines the use of archived weigh-in-motion (WIM) data to estimate link-based heavy-vehicle emissions for Oregon highways. This research combined data on vehicle speed, highway grade, and gross vehicle weight and relationship between these elements in published research to estimate the carbon dioxide (CO2) and nitrogen oxide (NOx) emissions from trucks. Sensitivity analysis was conducted on the impact of uphill grade and gross vehicle weight on truck speed and emissions. The results suggest that with the data available in the weigh-in-motion archive and with a reasonable set of assumptions, link-based emissions for heavy-duty vehicles can be estimated. The carbon dioxide (CO2) and nitrogen oxide (NOx) emissions are found to increase when the speed, gross vehicle weight, or road grade increases. The relationship between nitrogen oxide (NOx) emissions and vehicle weight was estimated to be linear. The potential to estimate the link-based heavy-vehicle emissions for Oregon highways using the weigh-in-motion data archive, which was mainly designed to estimate truck counts, has a great value in setting new measures to mitigate the heavy-vehicle emissions.
12

On-Road Remote Sensing of Motor Vehicle Emissions: Associations between Exhaust Pollutant Levels and Vehicle Parameters for Arizona, California, Colorado, Illinois, Texas, and Utah

Dohanich, Francis Albert 05 1900 (has links)
On-road remote sensing has the ability to operate in real-time, and under real world conditions, making it an ideal candidate for detecting gross polluters on major freeways and thoroughfares. In this study, remote sensing was employed to detect carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxide (NO). On-road remote sensing data taken from measurements performed in six states, (Arizona, California, Colorado, Illinois, Texas, and Utah) were cleaned and analyzed. Data mining and exploration were first undertaken in order to search for relationships among variables such as make, year, engine type, vehicle weight, and location. Descriptive statistics were obtained for the three pollutants of interest. The data were found to have non-normal distributions. Applied transformations were ineffective, and nonparametric tests were applied. Due to the extremely large sample size of the dataset (508,617 records), nonparametric tests resulted in "p" values that demonstrated "significance." The general linear model was selected due to its ability to handle data with non-normal distributions. The general linear model was run on each pollutant with output producing descriptive statistics, profile plots, between-subjects effects, and estimated marginal means. Due to insufficient data within certain cells, results were not obtained for gross vehicle weight and engine type. The "year" variable was not directly analyzed in the GLM because "year" was employed in a weighted least squares transformation. "Year" was found to be a source of heteroscedasticity; and therefore, the basis of a least-squares transformation. Grouped-years were analyzed using medians, and the results were displayed graphically. Based on the GLM results and descriptives, Japanese vehicles typically had the lowest CO, HC, and NO emissions, while American vehicles ranked high for the three. Illinois, ranked lowest for CO, while Texas ranked highest. Illinois and Colorado were lowest for HC emissions, while Utah and California were highest. For NO, Colorado ranked highest with Texas and Arizona, lowest.
13

The effect of fuel formulation on the exhaust emissions of spark ignition engines

Bell, Arthur 03 1900 (has links)
Thesis (PhD (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2006. / The research described in this dissertation examined the effects that fuel formulation can have on the regulated exhaust emissions produced by spark ignition engines in a South African context. Typical South African engine technology, and fuels representative of available fuels were investigated. To broaden the scope and provide information on as many fuel parameters as possible, fuel formulations other than typical retail fuels were also investigated. In order to gain insight into the mechanisms taking place, combustion analysis was performed on measured cylinder pressure traces
14

Cleaner alternative fuels for vehicles: a cleaner future for Hong Kong

Ng, Bing, Benson., 吳賓. January 2001 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
15

Controlling vehicular emissions in an era of rapid motorization: a case study of Guangzhou

Lee, Ka-yin, Anna., 李家賢. January 2009 (has links)
published_or_final_version / Geography / Master / Master of Philosophy
16

Divided-chamber automotive diesel engine : development and validation of a performance and emissions model

Mansouri, Seyed Hossein January 1982 (has links)
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Seyed Hossein Mansouri. / Ph.D.
17

Mechanistic Investigation of Novel Niobium-Based Materials as Enhanced Oxygen Storage Components and Innovative CO Oxidation Catalyst Support for Environmental Emission Control Systems

Leung, Emi January 2016 (has links)
Nb-doped ZrO₂-CeO₂-Y₂O₃ solid solution (Nb-ZrCeYO) is studied as a possible oxygen storage component in three way automobile exhaust catalysts. It shows enhanced oxygen storage (OS) capacity with a higher extent of reduction at temperatures within the typical operating range of three-way catalyst compared with solid solutions without Nb. However, after several days of exposure to ambient air, the OS behavior of the Nb-doped samples shows significant degradation. Degradation is slowed for samples stored in evacuated environments (i.e. vacuum sealed glass tubes). NbOₓ segregation to the surface under oxidizing conditions is hypothesized as the cause of the degradation. This hypothesis is consistent with the temperature programmed reduction data. The addition of small amounts of Pt to the aged samples restores the enhanced initial performance advantages. It is postulated that electrons supplied by metallic Pt mimic reducing conditions, which are known to re-disperse surface NbOₓ species into the bulk solid solution, leading to stable, time-independent OS performance. However, the small advantage caused by Nb addition over the current technology is insignificant for the TWC application. Therefore, we focus on other environmental applications such as CO oxidation by Nb-containing catalysts with the specific objective of enhanced CO oxidation activity by formation of Cu¹⁺ species supported on Nb₂O₅. The preparation of a Cu(1)Nb(2)Oₓ results in a solid solution crystallized in three different phases: CuO, Nb₂O₅, and CuNb₂O₆. The solid solution shows enhanced low temperature CO oxidation (<155˚C) activity compared to the reference CuO solid solution. Analysis by hydrogen-temperature programmed reduction (H2-TPR) indicates there are two different Cu species in the Nb-containing solid solution: highly dispersed Cu species and bulk CuO. The existence of an interaction between Cu and Nb ions is hypothesized for the enhanced low temperature CO oxidation activity by formation of Cu⁺¹. This hypothesis is consistent with XPS data, indicating the existence of more catalytically active Cu¹⁺/⁰ and Cu²⁺ species in the Nb₂O₅ sample, where the reference bulk CuO oxide shows only the less active Cu²⁺ species. Impregnation of Cu-containing precursor salts on the Nb₂O₅ support leads to enhanced CO oxidation activity: The Cu supported Nb₂O₅ sample shows improved CO oxidation activity compared with the reference Cu supported on Al₂O₃. An isothermal aging test shows high stability of the Cu¹⁺ species on the Nb₂O₅ support at 155˚C for 20 hours in air. Studies of the optimization of the Cu supported Nb₂O₅ leads one to conclude that low surface coverage of NbOx on Al₂O₃ is the reason why these samples shows lower CO oxidation activity. The optimal amount of Cu species on the Nb₂O₅ support is 6%, where activity is similar to 1%Pt/Al₂O₃, the state of the art CO oxidation catalyst in industry, but a phase transformation of Nb₂O₅ occurring at 800˚C, leads to a loss in the enhanced CO activity. A gradual loss in surface area is observed for samples aged at higher temperatures, indicating support sintering as the main cause of the performance deterioration. Stable performance at low temperatures makes CuOₓ/Nb₂O₅ a potential candidate for stationary abatement applications, which operate at temperatures <400˚C. Advanced aging would be necessary to qualify it for specific applications. A kinetic model for CO oxidation of CuOₓ/Nb₂O₅ is also developed.
18

Bioremediation of roadside pollutants NO₂ and benzene by integrating angiosperm Wedelia trilobata and spent compost of basidiomycete Pleurotus pulmonarius.

January 2011 (has links)
Lee, Ching Yuen. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 275-288). / Abstracts in English and Chinese. / List of Figures --- p.vii / List of Tables --- p.xv / List of Abbreviations and Symbols Used --- p.xix / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Roadside Air Pollution Problem --- p.1 / Chapter 1.1.1 --- Nitrogen Dioxide --- p.9 / Chapter 1.1.2 --- Benzene --- p.12 / Chapter 1.1.3 --- Heat and Noise --- p.13 / Chapter 1.2 --- Treatment Methods for Removal of Ambient Air Pollutants --- p.15 / Chapter 1.2.1 --- Physical and Chemical Methods --- p.15 / Chapter 1.2.2 --- Bioremediation --- p.17 / Chapter 1.2.3 --- Passive System and Active System --- p.18 / Chapter 1.3 --- Research Strategy --- p.18 / Chapter 1.3.1 --- Plant as a Bioremediating Agent --- p.18 / Chapter 1.3.2 --- Spent Mushroom Compost (SMC) as a Bioremediating Agent --- p.20 / Chapter 1.3.3 --- An Integrated System for Air Bioremediation --- p.24 / Chapter 1.3.4 --- Aim and Objectives of the Project --- p.24 / Chapter 1.4 --- Significance of the Project --- p.25 / Chapter 2. --- Materials and Methods --- p.26 / Chapter 2.1 --- Source of Materials --- p.28 / Chapter 2.1.1 --- Ingredients of Plant Growth Substrate --- p.28 / Chapter 2.1.2 --- Plants --- p.30 / Chapter 2.2 --- Formulation of the Plant Substrate --- p.31 / Chapter 2.2.1 --- Water Holding Capacity --- p.31 / Chapter 2.2.2 --- Water Retention --- p.32 / Chapter 2.2.3 --- Seed Germination Toxicity and Tissue Elongation --- p.33 / Chapter 2.2.4 --- Bulk Density and Porosity --- p.34 / Chapter 2.2.5 --- Substrate Shrinkage --- p.35 / Chapter 2.3 --- Characterization of the Materials --- p.36 / Chapter 2.3.1 --- pH --- p.36 / Chapter 2.3.2 --- Electrical Conductivity --- p.36 / Chapter 2.3.3 --- % Organic Matter --- p.37 / Chapter 2.3.4 --- "Nutrient Contents (Nitrogen, Phosphorus, Potassium, Magnesium, Calcium, Sodium, Iron)" --- p.37 / Chapter 2.3.5 --- Total Organic Carbon --- p.40 / Chapter 2.3.6 --- Detection for Heavy Metal Contaminants --- p.40 / Chapter 2.3.7 --- Detection for Organic Contaminants --- p.41 / Chapter 2.3.8 --- Extraction Efficiency of Heavy Metal Content and Organic Contaminants --- p.43 / Chapter 2.3.9 --- Outdoor Growing Trial of the Bioremediation System using Various Plant Species --- p.45 / Chapter 2.4 --- Characterization of the Plant --- p.47 / Chapter 2.4.1 --- Leaf Area Estimation --- p.47 / Chapter 2.4.2 --- Density of Plantlet --- p.48 / Chapter 2.4.3 --- Growth Rate of Plantlet in Water --- p.49 / Chapter 2.5 --- Temperature Stabilization Test --- p.50 / Chapter 2.6 --- NO2 Removal Test --- p.52 / Chapter 2.6.1 --- Preparation of Plantlets --- p.52 / Chapter 2.6.2 --- Generation and Sampling of NO2 --- p.52 / Chapter 2.6.3 --- Effect of N02 Concentration on RE --- p.55 / Chapter 2.6.4 --- Effect of Various Combinations in the Bioremediation System --- p.56 / Chapter 2.6.5 --- "Comparison to Photocatalytic Paint, Physical Sorbents and Other Planting Media" --- p.57 / Chapter 2.6.6 --- Effect of Temperature --- p.60 / Chapter 2.6.7 --- Effect of Retention Time --- p.61 / Chapter 2.6.8 --- Effect of Exposed Time --- p.61 / Chapter 2.6.9 --- Composition Analysis --- p.62 / Chapter 2.6.10 --- Post Tests after N02 Removal Test --- p.63 / Chapter 2.6.11 --- Chlorophyll and Carotenoid Contents --- p.63 / Chapter 2.6.12 --- Phenolic Content --- p.64 / Chapter 2.6.13 --- Total Microbial Count --- p.65 / Chapter 2.6.14 --- Activities of Antioxidative Enzymes --- p.66 / Chapter 2.6.15 --- Nitrite Oxidizing Enzyme --- p.68 / Chapter 2.7 --- Benzene Removal Test --- p.69 / Chapter 2.7.1 --- Preparation of Plantlets --- p.69 / Chapter 2.7.2 --- Generation and Sampling of Benzene --- p.69 / Chapter 2.7.3 --- Effect of Benzene Concentration on RE --- p.74 / Chapter 2.7.4 --- Effect of Various Combinations in the Bioremediation System --- p.75 / Chapter 2.7.5 --- Effect of Temperature --- p.76 / Chapter 2.7.6 --- Effect of Exposed Time --- p.77 / Chapter 2.7.7 --- Effect of Retention Time --- p.78 / Chapter 2.7.8 --- Composition Analysis --- p.78 / Chapter 2.7.9 --- "Comparison to Physical Sorbents, Photocatalytic Paint and Other Planting Media" --- p.79 / Chapter 2.7.10 --- Trials in Order to Increase RE of Benzene --- p.80 / Chapter 2.7.11 --- Residual Benzene in Substrate --- p.83 / Chapter 2.7.12 --- Post Tests after Benzene Removal Test --- p.84 / Chapter 2.7.13 --- Catechol Oxidase Activity --- p.85 / Chapter 2.8 --- Removal Tests for Other Air Pollutants --- p.86 / Chapter 2.9 --- Field Study --- p.88 / Chapter 2.10 --- Statistical Analysis --- p.98 / Chapter 3. --- Results --- p.99 / Chapter 3.1 --- Formulation of Plant Substrate --- p.99 / Chapter 3.1.1 --- Dose of SMC in Substrate Formula --- p.99 / Chapter 3.1.2 --- Dose of SAP in Substrate Formula --- p.105 / Chapter 3.1.3 --- Dose of Rice Hull in Substrate Formula --- p.111 / Chapter 3.2 --- Characterization of the Optimized Wedelia- growing Substrate --- p.118 / Chapter 3.2.1 --- Physical and Chemical Analysis --- p.118 / Chapter 3.2.2 --- Nutrient and Metal Contents --- p.120 / Chapter 3.2.3 --- Detection of Heavy Metal Contaminants --- p.124 / Chapter 3.2.4 --- Detection for Organic Contaminants --- p.126 / Chapter 3.3 --- Outdoor Growing Trial of Various Plants --- p.138 / Chapter 3.4 --- Plant Characterization --- p.143 / Chapter 3.4.1 --- Growth Rate of Plantlets in Water --- p.143 / Chapter 3.5 --- Temperature Stabilization Test --- p.146 / Chapter 3.6 --- NO2 Removal Test --- p.149 / Chapter 3.6.1 --- Effect of NO2 Concentration on RE --- p.149 / Chapter 3.6.2 --- Effect of Various Combinations in the Bioremediation System --- p.156 / Chapter 3.6.3 --- "Comparison to Photocatalytic Paint, Physical Sorbents and Other Planting Media" --- p.160 / Chapter 3.6.4 --- Effect of Temperature --- p.164 / Chapter 3.6.5 --- Effect of Retention Time --- p.166 / Chapter 3.6.6 --- Effect of Exposed Time --- p.168 / Chapter 3.6.7 --- Post Test Results After Various Exposed Times --- p.170 / Chapter 3.6.8 --- Microbial Count After Various Exposed Times --- p.176 / Chapter 3.6.9 --- Contribution of the Components of the Bioremediation System to Remove NO2 --- p.178 / Chapter 3.7 --- Benzene Removal Test --- p.183 / Chapter 3.7.1 --- Effect of Benzene Concentration on RE --- p.183 / Chapter 3.7.2 --- Effect of Various Combinations in the Bioremediation System --- p.186 / Chapter 3.7.3 --- Effect of Temperature --- p.190 / Chapter 3.7.4 --- Effect of Retention Time --- p.192 / Chapter 3.7.5 --- Effect of Exposed Time --- p.194 / Chapter 3.7.6 --- Contribution of Components of the Bioremediation System to Remove Benzene --- p.198 / Chapter 3.7.7 --- Optimization of the Benzene Removal of the Bioremediation System --- p.200 / Chapter 3.7.8 --- "Comparison to Photocatalytic Paint Coatings, Physical Sorbents and Other Planting Media" --- p.204 / Chapter 3.8 --- Removal Test for Other Air Pollutants --- p.208 / Chapter 3.9 --- Field Study I --- p.210 / Chapter 3.9.1 --- Environmental Parameters --- p.210 / Chapter 3.9.2 --- Noise --- p.212 / Chapter 3.9.3 --- Removal versus Distance --- p.213 / Chapter 3.9.4 --- Barrier Effect by Canvas --- p.216 / Chapter 3.9.5 --- NO2 Concentration --- p.216 / Chapter 3.9.6 --- VOC Concentration --- p.218 / Chapter 3.10 --- Field Study II --- p.220 / Chapter 3.10.1 --- Environmental Parameters --- p.220 / Chapter 3.10.2 --- Noise --- p.222 / Chapter 3.10.3 --- NO2 Concentration --- p.224 / Chapter 3.10.4 --- VOC Concentration --- p.225 / Chapter 4. --- Discussion --- p.228 / Chapter 4.1 --- Formulation of a Plant-growing Substrate --- p.228 / Chapter 4.2 --- Temperature Stabilization --- p.231 / Chapter 4.3 --- Dynamic Flow Through System in Pollutant Removal Experiment --- p.233 / Chapter 4.4 --- N02 Removal Test --- p.237 / Chapter 4.4.1 --- Limiting Factors of NO2 Removal --- p.237 / Chapter 4.4.2 --- Adsorption Isotherm --- p.239 / Chapter 4.4.3 --- Contribution of NO2 Removal by Various Components --- p.241 / Chapter 4.4.4 --- Comparison of NO2 Removal with Other Systems --- p.242 / Chapter 4.4.5 --- Comparison of NO2 Removal with Other Studies --- p.246 / Chapter 4.4.6 --- Toxicity of NO2 towards the Bioremediation System --- p.247 / Chapter 4.5 --- Interpretation of Results in Benzene Removal Test --- p.251 / Chapter 4.5.1 --- Limiting Factors of Benzene Removal --- p.251 / Chapter 4.5.2 --- Adsorption Isotherm --- p.253 / Chapter 4.5.3 --- Contribution of Benzene Removal by Various Components --- p.254 / Chapter 4.5.4 --- Comparison of Benzene Removal with Other Systems --- p.255 / Chapter 4.5.5 --- Trials in Order to Increase RE of Benzene --- p.256 / Chapter 4.5.6. --- Comparison of Benzene Removal with Other Studies --- p.258 / Chapter 4.6 --- Removal of Other Air Pollutants --- p.261 / Chapter 4.7 --- Field Studies with the Vertical Panels of the Bioremediation System --- p.264 / Chapter 4.7.1 --- Barrier Effect by Canvas --- p.264 / Chapter 4.7.2 --- Temperature Buffering --- p.265 / Chapter 4.7.3 --- Sound Attenuation --- p.266 / Chapter 4.7.4 --- NO2 and VOC Removal --- p.268 / Chapter 5. --- Conclusion --- p.272 / Chapter 6. --- Further Investigation --- p.274 / Chapter 7. --- References --- p.275
19

Automobile-generated air pollution

Muneer, T. (Tariq) January 2011 (has links)
Digitized by Kansas Correctional Industries
20

Atlanta automotive particulate matter exposure and evaluation

Boswell, Colin R. 02 July 2010 (has links)
The following thesis titled, Atlanta Automotive Particulate Matter Exposure and Evaluation, presents data obtained as a part of a joint project with Emory University, Rollin's School of Public Health. The Atlanta Commuters Exposure (ACE) Study uses both real-time and time-integrated sampling techniques for ambient aerosol concentrations. The ACE study is unique in that it will correlate the ambient aerosol concentrations with the concurrent health measurements. The primary objective of this thesis is to measure the concentration, size distribution and the chemical composition of PM2.5 inside the vehicle cabin for several commuters. The vehicles followed a scripted route along roadways in the Atlanta metropolitan region during periods of peak traffic volume, while the compact air sampling package of both real-time and time-integrated instruments recorded data. Real-time measurements for Particulate Matter (PM) were made using compact Optical Particle Counters (OPC), a Condensation Particle Counter, and a MicroAethalometer. The time-integrated measurements for Elemental Carbon (EC), Organic Carbon (OC), Water Soluble Organic Carbon (WSOC), particulate elemental concentrations, and speciated organics required filter collection methods. Thus a compact air-sampling package was created to combine both sets of real-time and time-integrated instruments. The following results are presented for the first four commutes. The framework for analyzing and presenting results is developed, and will be used for future commutes.

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