Although many nations have recognized the need to protect the Earth’s climate, human activities are continuing to result in a change in greenhouse gas levels that threaten to result in a detrimental change in the Earth’s climate in terms of ongoing human life. The EU ETS has been developed and implemented in Europe as a key tool to meet the goals set by the Kyoto Protocol. Much political debate has arisen in recent years regarding the implementation of a carbon-trading regime in the United States. Many commentators have recognized that the success of any proposed carbon regime will be determined by how well it is tailored to fit certain economic realities in the United States. However, the adequacy of proposed carbon trading frameworks with regard to potential linkage to existing systems, namely the EU ETS, raises additional considerations. My study seeks to expose these considerations for debate and determine whether existing political considerations in the United States are adequate for the establishment of future linkages or whether further measures are required.

Bubble and cavitation effects phenomena can be encountered in two-phase gas-liquid systems in industry. In certain industries, particularly high-risk systems such as a nuclear reactor/plant, the detection of bubble dynamics, and the monitoring and measurement of their characteristics are necessary in controlling temperature. While in the petro-chemical engineering industry, such as oil transportation pipelines, the detection and monitoring of bubbles/cavitation phenomena are necessary to minimise surface erosion in fluid carrying components or downstream facilities. The high sensitivity of Acoustic Emission (AE) technology is feasible for the detection and monitoring of bubble phenomena in a two phase gas-liquid system and is practical for application within the industry. Underwater measurement of bubble oscillations has been widely studied using hydrophones and employing acoustic techniques in the audible range. However, the application of Acoustic Emission (AE) technology to monitor bubble size has hitherto not been attempted. This thesis presents an experimental investigation aimed at exploring AEs from gas bubble formation, motion and destruction. AE in this particular investigation covers the frequency range of between 100 kHz to 1000 kHz. The AE waveform analysis showed that the AE parameter from single bubble inception and burst events, i.e. AE amplitude, AE duration and AE energy, increased with the increase of bubble size and liquid viscosity. This finding significantly extends the potential use of AE technology for detecting the presence of bubbles in two-phase flow. It is concluded that bubble activity can be detected and monitored by AE technology both intrusively and non-intrusively. Furthermore, the bubble size can be determined by measurement of the AE and this forms the significant contribution of this thesis.

With steadily increasing emissions regulations being imposed by government agencies, automobile manufacturers have been developing technologies to mitigate NOX emissions. Furthermore, there has been increasing focus on CO2 emissions. An effective approach for CO2 reduction is using lean burn engines, such as the diesel engine. An inherent problem with lean-burn engine operation is that NOX needs to be reduced to N2, but there is an excess of O2 present. NOX storage and reduction (NSR) is a promising technology to address this problem. This technology operates in two phases; where in the lean phase, normal engine operation, NOX species are stored as nitrates, and in a reductant rich phase, relative to O2, the NOx storage components are cleaned and the NOX species reduced to N2. In this study, the effects of reductant type, specifically CO and/or H2, and their amounts as a function of temperature on the trapping and reduction of NOX over a commercial NSR catalyst have been evaluated. Overall, the performance of the catalyst improved with each incremental increase in H2 concentration. CO was found ineffective at 200°C due to precious metal site poisoning. The addition of the H2 to CO-containing mixtures resulted in improved performance at 200°C, but the presence of the CO still resulted in decreased performance in comparison to activity when just H2 was used. At 300-500°C, H2, CO, and mixtures of the two were comparable for trapping and reduction of NOX, although the mixtures led to slightly improved performance. Although NSR technology is very efficient in reducing NOX emissions, a significant challenge that questions their long-term durability is poisoning by sulfur compounds inherently present in the exhaust. Therefore, during operation, NSR catalysts require an intermittent high-temperature exposure to a reducing environment to purge the sulfur compounds from the catalyst. This desulfation protocol ultimately results in thermal degradation of the catalyst. As a second phase of this study, the effect of thermal degradation on the performance of NSR technology was evaluated. The catalyst performance between a 200 to 500°C temperature range, using H2, CO, and a mixture of both H2 and CO as reductants was tested before and after different high-temperature aging steps. Tests included water-gas shift (WGS) reaction extent, NO oxidation, NOX storage capacity, oxygen storage capacity (OSC), and NOX reduction efficiency during cycling. The WGS reaction extent was affected by thermal degradation, but only at low temperature. NO oxidation did not show a consistent trend as a function of thermal degradation. The total NOX storage capacity was tested at 200, 350 and 500°C. Little change was observed at 500°C with thermal degradation and a steady decrease was observed at 350°C. At 200°C, there was also a steady decrease of NOX storage capacity, except after aging at 700°C, where the capacity increased. There was also a steady decrease in oxygen storage capacity at test temperatures between 200 and 500°C after each increase in thermal degradation temperature, except again when the sample was degraded at 700°C, where an increase was observed. In the cycling experiments, a gradual drop in NOX conversion was observed after each thermal degradation temperature, but when the catalyst was aged at 700°C, an increase in NOX conversion was observed. These data suggest that there was redispersion of a trapping material component during the 700°C thermal degradation treatment while the oxygen storage capacity data indicate redispersion of oxygen storage components. It therefore seems likely that it is these oxygen storage components that are becoming ‘‘activated’’ as trapping materials at low temperature.

The objective of this research is to build a prototype of a carbon nanotube (CNT)-based micro X-ray tube array, which can be used in a real-time cone-beam computed tomography (CT) scanner for cancer research. The X-ray tube array consists of an electron source, control grids, focusing electrodes, and an anode plate. All the experiments have been executed in an ultra high vacuum environment at a pressure of 10⁻⁷ Torr. A thin film consisting of multi-wall carbon nanotubes (MWNTs) was used as the electron source. A diode configuration was employed to test the field emission performance of the CNT thin film. The current density achieved was 1mA/cm² at 10V/µm. After the initial burn-in process, a relatively steady emission current was obtained for duration of 170 hours. The control grid was made of 25% opening space stainless steels mesh. Meshes with different wire diameters were tested in a triode structure, and some differences were observed. Multi-anode field emission tests and multi-tube electric field simulations were executed. Experiments and simulations have revealed crosstalk between pixels during field emission. Based on the above experiments and simulations, a signal pixel prototype has been fabricated and is being tested. Moreover, some potential optimizations that will be used in the second prototype are also discussed

In this research water emission is modeled from intermediate mass star formations regions placed at 1 kpc. Nine models are created to describe these regions of varying source luminosity ($L=100,500,$ and $1000L_{\odot}$) and protostellar envelope mass ($M=10,100,$ and $500M_{\odot}$). For each model, an intermediate mass class 0 protostar is centrally embedded in a spherically symmetry static protostellar envelope. Radiation transfered through these regions is calculated using the program RATRAN that applies an accelerated Monte Carlo method to obtain level population profiles of water. The level populations are used to determine the emission distribution of water from the regions by using a ray tracing method. Strong correlations between line ratios, integrated intensities and source luminosity are found. Larger envelope masses resulted in more mass going in the outer envelope where the water is frozen and does not contribute to the water emission and absorption. Line strengths, ratios, and integrated intensities for all the spectral lines of water within Herschel's observation range are tabulated.

A variety of factors make semiconducting polymers a fascinating alternative for both device development and new areas of fundamental research. Among these are solution processability, low cost, flexibility, and the strong dependence of conduction on the presence of charge compensating ions. With the lack of a complete fundamental understanding of the materials, and the growing demand for novel solutions to semiconductor device design, research in the field can take many, often multifaceted, routes. Due to ion-mediated conduction and versatility of fabrication, conducting polymers can provide a route to the study of neural signaling. In the first of three research topics presented, junctions of polypyrrole electropolymerized on microelectrode arrays are demonstrated. Individual junctions, when synthesized in a three-electrode configuration, exhibit current switching behavior analogous to neural weighting. Junctions copolymerized with thiophene exhibit current rectification and the nonlinear current-voltage behavior requisite for complex neural systems. Applications to larger networks, and eventual use in analysis of signaling, are discussed. In the second research topic, nonvolatile resistive memory consisting of gold nanoparticles embedded in a polymer film is examined using admittance spectroscopy. The frequency dependence of the devices indicates space-charge-limited transport in the high-conductivity "on" state, and similar transport in the lower-conductivity "off" state. Furthermore, a larger dc capacitance of the on state indicates that a greater amount of filling of midgap trap levels introduced by the nanoparticles increases conductivity, leading to the memory effect. Implications on the question as to whether or not the on state is the result of percolation pathways is discussed. The third and final research topic is a presentation of enhanced efficiency of polymer light-emitting electrochemical cells (LECs) by means of forming a doping self-assembled monolayer (SAM) at the cathode-polymer interface. The addition of the SAM causes a twofold increase in quantum efficiency. Photovoltaic analysis indicates that the SAM increases both open-circuit voltage and short-circuit current. Current versus voltage data are presented which indicate that the SAM does not simply introduce an interfacial dipole layer, but rather provides a fixed doping region, and thus a more stable p-i-n structure.

With steadily increasing emissions regulations being imposed by government agencies, automobile manufacturers have been developing technologies to mitigate NOX emissions. Furthermore, there has been increasing focus on CO2 emissions. An effective approach for CO2 reduction is using lean burn engines, such as the diesel engine. An inherent problem with lean-burn engine operation is that NOX needs to be reduced to N2, but there is an excess of O2 present. NOX storage and reduction (NSR) is a promising technology to address this problem. This technology operates in two phases; where in the lean phase, normal engine operation, NOX species are stored as nitrates, and in a reductant rich phase, relative to O2, the NOx storage components are cleaned and the NOX species reduced to N2. In this study, the effects of reductant type, specifically CO and/or H2, and their amounts as a function of temperature on the trapping and reduction of NOX over a commercial NSR catalyst have been evaluated. Overall, the performance of the catalyst improved with each incremental increase in H2 concentration. CO was found ineffective at 200°C due to precious metal site poisoning. The addition of the H2 to CO-containing mixtures resulted in improved performance at 200°C, but the presence of the CO still resulted in decreased performance in comparison to activity when just H2 was used. At 300-500°C, H2, CO, and mixtures of the two were comparable for trapping and reduction of NOX, although the mixtures led to slightly improved performance. Although NSR technology is very efficient in reducing NOX emissions, a significant challenge that questions their long-term durability is poisoning by sulfur compounds inherently present in the exhaust. Therefore, during operation, NSR catalysts require an intermittent high-temperature exposure to a reducing environment to purge the sulfur compounds from the catalyst. This desulfation protocol ultimately results in thermal degradation of the catalyst. As a second phase of this study, the effect of thermal degradation on the performance of NSR technology was evaluated. The catalyst performance between a 200 to 500°C temperature range, using H2, CO, and a mixture of both H2 and CO as reductants was tested before and after different high-temperature aging steps. Tests included water-gas shift (WGS) reaction extent, NO oxidation, NOX storage capacity, oxygen storage capacity (OSC), and NOX reduction efficiency during cycling. The WGS reaction extent was affected by thermal degradation, but only at low temperature. NO oxidation did not show a consistent trend as a function of thermal degradation. The total NOX storage capacity was tested at 200, 350 and 500°C. Little change was observed at 500°C with thermal degradation and a steady decrease was observed at 350°C. At 200°C, there was also a steady decrease of NOX storage capacity, except after aging at 700°C, where the capacity increased. There was also a steady decrease in oxygen storage capacity at test temperatures between 200 and 500°C after each increase in thermal degradation temperature, except again when the sample was degraded at 700°C, where an increase was observed. In the cycling experiments, a gradual drop in NOX conversion was observed after each thermal degradation temperature, but when the catalyst was aged at 700°C, an increase in NOX conversion was observed. These data suggest that there was redispersion of a trapping material component during the 700°C thermal degradation treatment while the oxygen storage capacity data indicate redispersion of oxygen storage components. It therefore seems likely that it is these oxygen storage components that are becoming ‘‘activated’’ as trapping materials at low temperature.

The objective of this research is to build a prototype of a carbon nanotube (CNT)-based micro X-ray tube array, which can be used in a real-time cone-beam computed tomography (CT) scanner for cancer research. The X-ray tube array consists of an electron source, control grids, focusing electrodes, and an anode plate. All the experiments have been executed in an ultra high vacuum environment at a pressure of 10⁻⁷ Torr. A thin film consisting of multi-wall carbon nanotubes (MWNTs) was used as the electron source. A diode configuration was employed to test the field emission performance of the CNT thin film. The current density achieved was 1mA/cm² at 10V/µm. After the initial burn-in process, a relatively steady emission current was obtained for duration of 170 hours. The control grid was made of 25% opening space stainless steels mesh. Meshes with different wire diameters were tested in a triode structure, and some differences were observed. Multi-anode field emission tests and multi-tube electric field simulations were executed. Experiments and simulations have revealed crosstalk between pixels during field emission. Based on the above experiments and simulations, a signal pixel prototype has been fabricated and is being tested. Moreover, some potential optimizations that will be used in the second prototype are also discussed

In this research water emission is modeled from intermediate mass star formations regions placed at 1 kpc. Nine models are created to describe these regions of varying source luminosity ($L=100,500,$ and $1000L_{\odot}$) and protostellar envelope mass ($M=10,100,$ and $500M_{\odot}$). For each model, an intermediate mass class 0 protostar is centrally embedded in a spherically symmetry static protostellar envelope. Radiation transfered through these regions is calculated using the program RATRAN that applies an accelerated Monte Carlo method to obtain level population profiles of water. The level populations are used to determine the emission distribution of water from the regions by using a ray tracing method. Strong correlations between line ratios, integrated intensities and source luminosity are found. Larger envelope masses resulted in more mass going in the outer envelope where the water is frozen and does not contribute to the water emission and absorption. Line strengths, ratios, and integrated intensities for all the spectral lines of water within Herschel's observation range are tabulated.

The objective of this research was to determine the effectiveness of nanoparticles for reducing gas and odour emissions from swine manure slurry using three deployment methods: headspace gas filtration, mixing with manure slurry and spraying into the headspace of manure slurry. <p> Filtering manure gas through the zinc oxide (ZnO) filter bed at a flow rate of 500 mL/min reduced ammonia (NH3), hydrogen sulphide (H2S) and odour concentrations by 74 to 99%. Methane (CH4) and carbon dioxide (CO2) concentrations of the filtered manure gas were decreased by 14% and 18%, respectively. Mixing ZnO into the manure slurry significantly reduced odour concentration by 79% and the hedonic tone was improved by 25% at one day after treatment application. Concentrations of CH4 and H2S were reduced by 54% and 98%; however concentrations of NH3 and nitrous oxide (N2O) were increased by 31% and 3%, respectively. Even though mixing of ZnO into the slurry influenced the gas and odour concentration, manure properties such as ammonia as N, TKN, P, K, S, Na, Ca, Mg, Cu, Fe, Mn, Z, total solids, % moisture, pH and EC were not changed except for an increase of 0.2 in pH value. Spraying tungsten oxide (WO3) into the headspace of manure slurry decreased the odour and CO2 concentration by 31 and 10%, but the reduction was not statistically significant (P>0.05).<p>Among the three deployment methods, filtration and mixing methods using ZnO were able to reduce NH3, H2S, and odour concentration. However, surface reactions between the manure gas components and nanoparticles should be investigated to increase the effectiveness of the treatment application. Likewise, knowing these reactions will facilitate the identification and manipulation of factors that influence the effectiveness of the deployment method. Economic, environmental and health assessment should be done to determine the feasibility and overall impact of using nanotechnology in reducing gas and odour emission to the swine industry.