Application of surface wave plasma technology for effective abatement of environmentally harmful gases such as perfluorocompounds and chlorofluorocarbons is investigated. Perfluorocompounds (PFCs) are gases that contribute to forced global warming and have been favored for wafer etch and chamber clean applications in the semiconductor industry. Chlorofluorocarbons (CFCs) are ozone depleting gases that were used as refrigerants for commercial and domestic condensers and air conditioners, but current reserves still pose threats to environmental sustainability. Increased average global temperatures and further destruction of the ozone layer have prompted proposal of international initiatives such as the Montreal Protocols and the Kyoto Agreement to curtail emissions of such fugitive gases into the environment. These have increased the need for effective abatement technologies to control such emissions and include surface wave plasma abatement, the subject of this dissertation. Surface wave plasmas are considered high frequency non-equilibrium traveling wave discharges in contrast to the more frequently used standing wave discharges. The use of surface wave plasmas have the advantages of a variety of discharge vessel shapes, reproducibility of application, numerous operating conditions and large plasma volumes which ultimately produce low, molecular weight byproducts that are associated with high effective electron temperatures but low heavy particle temperatures. For these reasons, surface wave plasma abatement technology was developed for the destruction and removal of PFCs and CFCs. Results include final destruction and removal efficiencies (DREs) for octafluorocyclobutane greater than 99.8%, dichlorodifluoromethane greater than 99.995% and trichlorofluoromethane greater than 99.999% using moderate applied microwave powers of less than 2000 watts with the production of low molecular weight byproducts, such as CO2, CO, HF and HCl, that prevent environmentally harmful process emissions from entering the atmosphere. Characterizations of the initial and final products were accomplished by the use of Fourier transform infrared spectroscopy and quadrupole mass spectrometry to provide independent quantitative analyses of plasma processes. In addition to these analytical methods, Global_Kin a kinetic model, of plasma reactions were conducted and compared to all the experimental data determined in order to facilitate understanding of the chemistry involved in the surface wave plasma abatement applications studied. Basic plasma reaction mechanisms were determined for the abatement of octafluorocyclobutane and dichlorodifluoromethane.

Thesis (M. Sc.)--University of Hong Kong, 1994. / Includes bibliographical references (leaves 67-69).

Thesis, PlanB (M.S.)--University of Wisconsin--Stout, 2005. / Includes bibliographical references.

Thesis--Auburn University, 2006. / Abstract. Includes bibliographic references (p.70-84).

The plasma abatement system co-developed by Rf Environmental, Inc. and Texas A & M University has been effective at destroying the global warming gases CF4 and C4F8. The destruction of greenhouse gases, specifically perfluorocompounds, hydrofluorocompounds, chlorofluorocompounds (PFCs, HFCs, CFCs) and SF6, is paramount to significantly affecting atmospheric pollution. The premise of this study was to examine the design of the plasma abatement system for Global Warming Gases (GWGs) and its abatement potential for these gases. The first goal was to reduce the cost of ownership by examining the cooling system. The cost of an air cooling design was $1400/yr. The intent was to reduce the amount of air used or use a different medium that would produce the same amount of heat transfer. A liquid cooling system design had a cost of only $150/yr. A C4F8 abatement experiment was run on the liquid cooling design. The abatement process resulted in a destruction removal efficiency (DRE) of C4F8 of 97.5 percent. A lower operational cost unit was developed, but the operational performance was less than previous investigations. The second goal was to simulate the semiconductor radio frequency etching process and abate the output gases of the C4F8 and SiO2 reaction. The outcomes of this experiment included a microwave simulation of the radio frequency etching reaction and an abatement that resulted in a 99.98 plus/minus .05 percent DRE for C4F8 with no formation of any other CFC gases. The third goal was to simulate the etching process and abate the output gas, CF4 using H2O vapor as the additive gas. The outcomes of this experiment included a microwave simulation of the radio frequency etching reaction and an abatement that resulted in a 99.96 plus/minus .05 percent DRE for CF4 with no formation of any other CFC gases. A low cost of ownership and effective abatement levels will make this system viable for commercial use. The latest data shows the amount of PFC emissions from the semiconductor industry was 3.6 Tg CO2 Eq. The use of this or a similar abatement technology will have a significant impact on reducing environmental pollution.

Climate Change has been related to GHG emissions, of both natural and anthropogenic origin. Agricultural management practices like reduced tillage and intensive cropping systems have a significant impact on the flow of C among its sources and sinks. These management practices involve complex biophysical interactions resulting in a range of impacts on farm income and GHG abatement. The focus of this study was on the impact of alternative annual crop tillage systems on GHG emissions and income to better inform climate change mitigation policy in agriculture. Besides tillage intensity, cropping intensity and crop mix and the interaction of these characteristics with the biological and physical attributes, the emission and income effects are a function of factor inputs, factor costs and commodity prices. Therefpre, the analysis was multi-disciplinary in nature and the tool of choice that depicts impacts on individual indicators is Trade-off Analysis (TOA). A component of risk analysis was also included. The analysis focused on short and long-term performance, the uncertainty of soil N2O emission coefficients as well as changes in weather patterns. As the adoption of reduced till has been a relatively recent development and as such, there is not a lot of long-term biophysical and economic data, which limits the effectiveness of econometric analysis. The different scenarios of uncertainty and long-term impacts were analysed by use of a simulation model. The model was parameterised with Intergovernmental Panel on Climate Change (IPCC) 1996 coefficients, a farmer survey, and cost data from Saskatchewan Agriculture Agri-Food and Rural Revitalization (SAFRR) for 2004. Results indicated that net GHG emissions were relatively lower for reduced tillage management while conventional tillage may be relatively more attractive from an economic perspective. However, results indicated that such economic factors as risk and economies of size may have a significant influence on this latter result. The study also highlighted the need to evaluate the GHG abatement potential of reduced tillage while simultaneously considering the abatement capability of the farm.

Climate Change has been related to GHG emissions, of both natural and anthropogenic origin. Agricultural management practices like reduced tillage and intensive cropping systems have a significant impact on the flow of C among its sources and sinks. These management practices involve complex biophysical interactions resulting in a range of impacts on farm income and GHG abatement. The focus of this study was on the impact of alternative annual crop tillage systems on GHG emissions and income to better inform climate change mitigation policy in agriculture. Besides tillage intensity, cropping intensity and crop mix and the interaction of these characteristics with the biological and physical attributes, the emission and income effects are a function of factor inputs, factor costs and commodity prices. Therefpre, the analysis was multi-disciplinary in nature and the tool of choice that depicts impacts on individual indicators is Trade-off Analysis (TOA). A component of risk analysis was also included. The analysis focused on short and long-term performance, the uncertainty of soil N2O emission coefficients as well as changes in weather patterns. As the adoption of reduced till has been a relatively recent development and as such, there is not a lot of long-term biophysical and economic data, which limits the effectiveness of econometric analysis. The different scenarios of uncertainty and long-term impacts were analysed by use of a simulation model. The model was parameterised with Intergovernmental Panel on Climate Change (IPCC) 1996 coefficients, a farmer survey, and cost data from Saskatchewan Agriculture Agri-Food and Rural Revitalization (SAFRR) for 2004. Results indicated that net GHG emissions were relatively lower for reduced tillage management while conventional tillage may be relatively more attractive from an economic perspective. However, results indicated that such economic factors as risk and economies of size may have a significant influence on this latter result. The study also highlighted the need to evaluate the GHG abatement potential of reduced tillage while simultaneously considering the abatement capability of the farm.

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Thesis(M.S.)--Auburn University, 2006. / Abstract. Includes bibliographic references.

Thesis (M.A.)--Humboldt State University, 2006. / Includes bibliographical references (leaves 57-62). Also available via Humboldt Digital Scholar.