• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 33
  • 9
  • 2
  • 1
  • 1
  • Tagged with
  • 58
  • 58
  • 58
  • 48
  • 29
  • 26
  • 22
  • 19
  • 19
  • 16
  • 15
  • 15
  • 14
  • 14
  • 9
  • 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.
21

Effect of high occupancy toll (HOT) lanes on mass vehicle emissions

Kall, David. January 2008 (has links)
Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Guensler, Randall; Committee Member: Rodgers, Michael; Committee Member: Ross, Catherine. Part of the SMARTech Electronic Thesis and Dissertation Collection.
22

Essays in vehicle emission policies

Mazumder, Diya Basu, 1974- 28 August 2008 (has links)
The first chapter of this dissertation examines welfare impacts of a combination of subsidies to alternative fuels (AFs) and alternative fuel vehicles (AFVs), and how they compare to gasoline taxes. The particular AF examined here is ethanol that is produced from agricultural products in a small open economy. The model in this paper characterizes a country or state where gasoline is the major source of fuel for automobiles, but that also produces and consumes ethanol as an AF. Gasoline combustion is polluting and its use equals the total amount of emissions produced. Thus, a gasoline tax here is the same as an emissions tax and is the most direct environmental instrument. However, increasing gasoline taxes for pollution purposes is often politically not feasible. Thus, this paper studies how closely subsidies to alternative fuels (AFs) and alternative fuel vehicles (AFVs) emulate abatement behavior from a unit gasoline tax in a simple three sector general equilibrium model, and in the presence of pre-existing labor taxes. The model can also be used to track the effects of each policy on outputs, exports, and fuel use. The analytical results of the model are then calibrated to data from the largest ethanol producing state in the U.S., namely Illinois. The paper finds that subsidies can achieve up to 64 percent of the welfare gains from the gasoline tax, if the uncompensated wage elasticity is low enough or the elasticities of substitution between the transportation goods is high enough. The second chapter estimates behavior of households who jointly make discrete decisions about vehicle ownership and continuous decisions about miles driven. The paper uses seven years of data from 1995-2001 for the 35 states and union territories of India. The estimated parameters will be used to calculate elasticities of each different type of vehicle for percentage changes in petrol price per unit distance travelled and in vehicle taxes. The paper also computes income and price elasticities for petrol consumption. Two types of vehicles predominant in India are cars and two-wheelers such as motorcycles, mopeds, and scooters. The latter type of vehicle is more fuel efficient than the former. However, patterns of vehicle ownership across the country reflect a growing number of cars relative to motorcycles. This paper investigates the impact alternative policies such as taxes on petrol or on cars have on efficient methods of vehicle emission abatement in India. In particular, the chapter estimates the effect of each such policy on vehicle choice and driving behavior, and how they in turn affect emissions. The main results are summarized as follows: First, continuous choice own-price elasticities are higher for 4w relative to 2w, given age, and for older vehicles relative to newer ones, within each category. Second, discrete choice own-price elasticities with respect to capital cost are higher for 2w relative to 4w. Moreover, older vehicles of each type are more sensitive to higher vehicle prices relative to their newer counterparts. Third, income elasticities for discrete vehicle choices are all positive and greater than unity. Thus, higher income encourages purchase of newer vehicles of each type. Moreover, usage of vehicles rises with income, conditional on the particular vehicle choice. Finally, the paper conducts simulations that alter the price per kilometer by adding either an additional gas tax, a distance tax or an emissions tax. Results show that a distance tax reduces vehicle kilometers traveled the most, followed by an emissions tax and lastly by the gas tax. However, local emissions are reduced the most by an emissions tax, followed by a distance tax and then by a gasoline tax. Even though it would be ideal to compare the results obtained in this paper to results generated using a micro-level data set, the estimates presented here are indicative of whether a distance tax or a gasoline tax is more effective for emissions abatement in India. The third chapter of this dissertation evaluates how information asymmetry in private automobile markets affects programs to accelerate vehicle retirement, also known as scrappage programs. We use a dynamic framework where agents have heterogenous preference for car quality. Cars can either be new, or used. While all new cars have the same quality, used cars can be of high- or low-quality. The quality of a car is perfectly correlated with emissions. The goal of a scrappage program is to induce car owners to voluntarily scrap low-quality used cars. One key result is that in the presence of adverse selection a subsidy that maintains an active resale market unambiguously makes all types of consumers better off. However, if this option of implementing the subsidy does not exist, then the only other way to induce effective scrappage in our framework is to shut down the used car market. Welfare implications suggest that it might be better not to do anything rather than have a scrappage program such as the latter. / text
23

The effects of fuel volatility, structure, speed and load on HC emissions from piston wetting in direct injection spark ignition engines

Huang, Yiquan 16 March 2011 (has links)
Not available / text
24

The vehicle emissions control policy in Hong Kong: a study of agenda setting

Wu, Wai-yu., 吳惠如. January 2000 (has links)
published_or_final_version / Public Administration / Master / Master of Public Administration
25

An analysis of the influence of phosphorus poisoning on the exhaust emission after treatement systems of light-duty diesel vehicles

Toral del Rio, Maria Isabel January 2007 (has links)
Climate change has become a discussion topic of exponentially increasing urgency and importance amoung world leaders of all disciplines. These changes are brought about by the emission of so-called Greenhouse gases from various human activities. The primary cause of CO2 emissions is the burning of the Earth’s supply of nonrenewable natural fossil fuels like coal, oil and natural gas. The world first agreed on the prevention of “dangerous” climatic changes at the Earth Summit in 1992. The Kyoto Protocol of 1997 was the first step toward protection of the atmosphere and prescribes restrictions on emission pollutants. Since then the vehicle gas emissions are being controlled by means of different gas emissions norms, like the European Union Norm in Europe. The automotive manufacturers and suppliers are collectively working on reducing overall vehicle emissions. They are focusing on several different emission limiting possibilities, for example improved engine design, special fuel development and exhaust gas treatment systems. The exhaust gas treatment process requires continuous controlling and management of the exhaust gas emissions while driving a vehicle. Certain factors such as high emission temperatures have a negative influence on the life span of these systems. Their functionality and durability is also known to be reduced by the presence of chemical poisoning species like sulphur, phosphorus, zinc and calcium. The chemical poisoning species are produced during combustion of fuel and engine oil. They are therefore contained in the exhaust emissions and can poison the catalyst when passing over it. Phosphorous poisoning is particularly problematic and should be reduced considerably. This study involves the investigation of the phosphorous poisoning process and aims to provide clarity regarding the influences of different fuel and oil compositions on the severity of the process. Engine oil and biodiesel are two major sources of phosphorous poisoning. The phosphorus contained in biodiesel fuel is a natural component and can be minimized during the refining procedure. In contrast to others studies, the biodiesel fuel used during this project was SME (Soya Methyl Ester) with a 20% biodiesel content. This choice of fuel was made because of the increasingly important role that this type of biodiesel is playing in the European market and the future tendency to increase the percentage of biodiesel in the mixture with standard diesel fuel. The phosphorus contained in engine oil is a necessary additive to retain the antioxidant and anti-wear properties of the oil. This study examined the poisoning influences from the most commonly used phosphorus containing oil additive, Zinc Dithiophosphates (ZDDP), as well as a Zn-free, phosphorus containing anti-wear oil additive. This formulation provides information about the phosphorus poisoning process as caused by the engine oil in the absence of Zn in the oil additives. The results show how the phosphorus content in biodiesel fuel affects the functionality of the exhaust gas treatment systems and the importance of reducing the permitted content of phosphorus contained in the fuel. Reducing the phosphorus content in the fuel will conserve the functionality of the exhaust gas treatment systems during their operational life and thereby protect the environmental from emission pollutants. It also provides insight into the differences in the poisoning processes when the phosphorus deposited on the catalyst comes from biodiesel fuel and when it comes from the engine oil. Finally the results also illustrate the influence of different phosphorous forms contained in engine oil additives on the catalyst poisoning process. This information could be used for the development of new oil additive formulations.
26

Alcohol Assisted Hydrocarbon Fuels: A Comparison of Exhaust Emissions, Power Output and Fuel Consumption Using Static and Dynamic Engine Test Facilities

Bushnell, Dwight J. 01 April 1975 (has links)
America’s energy crunch— something new for a country that has been used to great affluence. America’s smog— an eye stinging, lung burning situation which the Environmental Protection Agency has "promised" to rectify. These are two outstanding problems that face the engineer and scientist of today. The end of the era of cheap gasoline has brought the beginnings of a quiet revolution to Detroit: an improvement in the efficiency, economy and emission level of the American automobile. Word has penetrated to the automotive engineers that the emissions level, fuel economy and automobile safety are the prime design considerations for the automobile of the future.
27

A neutron activation analysis investigation of traceable elements from automobile exhaust in roadside soil and vegetation

Oakes, Thomas Wyatt 08 June 2010 (has links)
The purpose of this work was to demonstrate the effectiveness of neutron activation analysis in studying a complex environmental problem. The area chosen for study was the exhaust emitted by automobiles and its dispersion into soil and selected plants near highways. The elements chosen for this study were the major traceable components of gasoline and automobile exhaust. Variations in the concentrations of these trace elements in soil, grass and wash off the grass at various distances from two highways were investigated. Of the elements found in gasoline and in automobile exhaust, bromine most clearly indicated where some of the atmospheric components were going and, therefore, would be the most suitable element for neutron activation studies of atmospheric and turbulence modeling and possibly for following biological effects of automobile traffic. / Master of Science
28

The effect of compression ratio on emissions from an alcohol-fueled engine

Cambridge, Shevonn Nathaniel 12 September 2009 (has links)
The motivation for this work stems from the enacting of stricter emissions requirements for the mid 1990's by the California Air Resources Board. It is foreseen that these requirements will favor the use of alcohol fuels in quantities comparable to the present usage of gasoline and diesel in order to reduce emissions of carbon monoxides (CO) and nitrogen oxides (NOx). The use of alcohol fuels at this level will substantially increase the amount of aldehyde emissions. This poses a problem in that aldehydes are odorants, components of photochemical smog, and volatile aldehydes are eye and respiratory tract irritants; therefore, it is only a matter of time before they too are strictly regulated. This thesis focuses on a systematic analysis of aldehyde emissions from alcohol fuels with respect to compression ratio. Compression ratio has been selected as the primary variable for this study, because alcohol-fueled vehicles are usually modified to have higher compression ratios than their gasoline-fueled counterparts in order to take advantage of alcohols' higher octane rating. The investigation is being conducted using a single-cylinder variable-compression ratio Waukesha-CFR engine. The aldehyde emissions are measured for various fuel alcohol percentages at different compression ratios and MBT timing. The effects on conventional vehicle emissions (Le. NOx, CO, unburned hydrocarbons) are also being measured so that tradeoffs between conventional emissions and aldehyde emissions can be determined. The goal of this research was to locate any trends between alcohol fuels and compression ratios which will allow for an optimization of these parameters to minimize aldehyde emissions. It was desired that this be achieved without sacrificing engine performance or increasing other regulated emissions. The variance of compression ratio was found to affect the pollutant formation process via its effects on temperature. The increasing expansion ratio, which accompanies increasing compression ratio, resulted in lower post .. expansion burned-gas temperatures. Temperature's influence on the rate of reactions was found to be the driving force in the formation of most of the pollutants. The experiment showed a definitive reduction in CO emissions with the use of alcohol fuels. The results also indicated an inherent tradeoff between NOx and formaldehyde emissions. / Master of Science
29

Simulating a block queuing system at a drive-thru restaurant to examine tradeoffs between fuel consumption and customer service

Berglin, Jon 01 July 2003 (has links)
No description available.
30

Differential exposure of the urban population to vehicular air pollution in Hong Kong.

January 2011 (has links)
Fan, Xiaopeng. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 101-108). / Abstracts in English and Chinese. / LIST OF FIGURES --- p.viii / LIST OF TABLES --- p.x / LIST OF ABBREVIATIONS --- p.xi / Chapter Chapter One - --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Hong Kong as a Case Study --- p.4 / Chapter 1.3 --- Research Objectives --- p.6 / Chapter 1.4 --- Significance of the Research --- p.7 / Chapter Chapter Two - --- LITERATURE REVIEW --- p.9 / Chapter 2.1 --- Introduction --- p.9 / Chapter 2.1.1 --- Origin of environmental justice --- p.9 / Chapter 2.1.2 --- Concept --- p.10 / Chapter 2.2 --- Review of environmental inequality studies --- p.12 / Chapter 2.2.1 --- The siting of hazardous waste treatment storage or disposal facilities --- p.12 / Chapter 2.2.2 --- Release of toxics from industries and facilities --- p.13 / Chapter 2.2.3 --- Population exposure to noise and air pollution --- p.15 / Chapter 2.2.3.1 --- Noise --- p.15 / Chapter 2.2.3.2 --- Air pollution --- p.16 / Chapter 2.2.4 --- Dissimilarity of the findings --- p.20 / Chapter 2.3 --- Research methodology --- p.21 / Chapter 2.3.1 --- Environmental indicators and parameters --- p.21 / Chapter 2.3.2 --- Pollution exposure assessment method --- p.22 / Chapter 2.3.3 --- Choice of socioeconomic indicators --- p.24 / Chapter 2.3.3.1 --- Demographic and socioeconomic indicators --- p.24 / Chapter 2.3.3.2 --- Source of socioeconomic data --- p.26 / Chapter 2.3.4 --- Study unit --- p.26 / Chapter 2.3.5 --- Analytical methods --- p.29 / Chapter 2.4 --- Factors contributing to inequality --- p.29 / Chapter 2.5 --- Summary --- p.31 / Chapter Chapter Three - --- RESEARCH METHODOLOGY --- p.33 / Chapter 3.1 --- Research Framework --- p.33 / Chapter 3.2 --- Study Unit and Sampling Strategy --- p.34 / Chapter 3.2.1 --- Study unit used in other studies --- p.35 / Chapter 3.2.2 --- Study unit --- p.35 / Chapter 3.2.3 --- Sampling Method --- p.37 / Chapter 3.3 --- Air pollution exposure assessment --- p.39 / Chapter 3.3.1 --- Assessment method --- p.40 / Chapter 3.3.2 --- Calculation of emission inventory --- p.42 / Chapter 3.3.2.1 --- Emission factors estimated by EMFAC-HK model --- p.42 / Chapter 3.3.2.2 --- Vehicular emission inventory --- p.44 / Chapter 3.3.3 --- Simulation by air pollution dispersion model --- p.44 / Chapter 3.3.3.1 --- IMMISnet Model --- p.44 / Chapter 3.3.3.2 --- Data requirement of MMISn e t Model --- p.45 / Chapter 3.3.3.3 --- Output ofIMMISnet Model --- p.49 / Chapter 3.4 --- Population socioeconomic indicators --- p.51 / Chapter 3.5 --- Analytical method --- p.53 / Chapter 3.6 --- Summary --- p.53 / Chapter Chapter Four - --- FINDINGS AND DISCUSSION --- p.55 / Chapter 4.1 --- Pollution Exposure Assessment --- p.55 / Chapter 4.2 --- The differential exposure of different age and SDI groups --- p.60 / Chapter 4.2.1 --- The selection of socioeconomic indicators --- p.60 / Chapter 4.2.2 --- Decile analysis --- p.64 / Chapter 4.2.2.1 --- Differential exposure based on age groups --- p.64 / Chapter 4.2.2.2 --- Differential exposure based on SDI groups --- p.71 / Chapter 4.3 --- Regression Analysis --- p.75 / Chapter 4.3.1 --- Pearson's correlation analysis --- p.75 / Chapter 4.3.2 --- Stepwise regression analysis --- p.81 / Chapter 4.4 --- Discussion --- p.87 / Chapter Chapter Five - --- CONCLUSION --- p.90 / Chapter 5.1 --- Introduction --- p.90 / Chapter 5.2 --- Summary of Findings --- p.90 / Chapter 5.3 --- Limitation of the study --- p.92 / Chapter 5.4 --- Recommendations for further study --- p.93 / APPENDIX --- p.94 / REFERENCES --- p.101

Page generated in 1.1842 seconds