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.

Os regulamentos de controle de emissões de exaustão de motores pequenos fora de estrada, recentemente introduzidos nos EUA e na Europa, exigem a realização de ensaios em motores, conhecidos como PLT – Production Line Testing. O presente trabalho apresenta uma sistemática para implantação deste programa de ensaios na linha de produção pelo fabricante. Neste trabalho foi identificada a oportunidade de utilizar métodos complementares para monitoramento e melhoria da qualidade, considerando requisitos do usuário e regulamentos. A sistemática proposta foi aplicada em uma empresa fabricante de motores durante a introdução de uma linha de produção e possibilitou a implantação do PLT com sucesso. O monitoramento da qualidade permitiu a identificação de informações adicionais, como tendências de afastamento do ajuste, que passariam despercebidas pelos métodos exigidos pelos regulamentos, e assim ajudou a prevenir a produção de unidades não-conformes. Finalmente, foi realizada uma otimização baseada em dados de testes compulsórios, que resultou em melhoria da qualidade sem custos adicionais. / Regulations for engine exhaust emissions control, recently introduced in the USA and Europe, demand engine testing, known as PLT – Production Line Testing. The present work suggests a systematic approach for implementation of such a manufacturer production line testing. The opportunity of integrating complementary methods for quality monitoring and improvement, considering both, regulations and user requirements, was identified. The proposed approach was applied for an engine manufacturer during introduction of a production line, allowing a successful implementation of PLT. The complementary quality monitoring allowed the identification of additional information, such as adjustment offset trends, that would have been unnoticed by only applying the methods as demanded by the regulations, and thus helped to prevent production of non-conforming products. An optimization based on data from compulsory tests was performed, resulting in quality improvements at no additional costs.

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

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Cette étude est dédiée à l’optimisation de capteurs chimiques de gaz de type résistifs à base de dioxyde d’étain (SnO2) pour l’application en ligne d’échappement automobile. Les capteurs sont élaborés par la technique de sérigraphie qui permet la production en masse de capteurs robustes sur substrat alumine. En vue de l’application automobile visée, les capteurs ont été optimisés par l’ajout d’une couche protectrice poreuse déposée sur l’élément sensible de SnO2. Le comportement de ces capteurs a été étudié en fonction de différents paramètres, comme la température et la vitesse des gaz, représentatifs de conditions d’échappement automobile. De plus, une modélisation « simple » de la réponse électrique des capteurs en fonction de la concentration d’un ou plusieurs gaz polluants cibles a été proposée. / This study is dedicated to the optimization of chemical gas sensors based on resistive type tin dioxide (SnO2) for automotive exhaust application. The sensors were produced by screen-printing technique which allows mass production of robust sensors on alumina substrate. In regards of the automotive application, the sensors were optimized by adding a porous protective layer deposited on the sensing element SnO2. The behaviour of this type of gas sensors was studied depending on gas parameters such as gas temperature and velocity, representative of real operation conditions. In addition, a “simple” modelisation of the electrical response of sensors depending on the concentration of one or more gaseous targets is proposed.

A greenhouse study was conducted to determine the effects of deposition from static rocket test fires on corn and alfalfa. Seeds were germinated in a wide concentration range of depositional material, called test fire soil (TFS). Additionally, the impact of chloride and aluminum, two major components of test fire soil, on germination was also evaluated. Furthermore, plants were grown in packed columns and exposed to test fire soil, either in the root zone or on foliage. Tissue was weighed and analyzed to compare biomass production and plant composition. Corn and alfalfa exposed to test fire soil in the root zone produced less biomass than controls, but foliar treatment had no effect on biomass production. No kernels were produced by corn exposed to test fire soil in the root zone. Leaves of plants exposed to test fire soil in the root zone accumulated more metals and nutrients than controls, whereas plant tissue treated with test fire soil on the leaves contained only elevated levels of aluminum, although levels were still within reasonable concentrations for plants. Germination of seeds was not affected below 1% test fire soil in soil; however higher concentrations of test fire soil decreased percent germination. Addition of chloride to soil also inhibits germination, but addition of aluminum has no effect on germination percentage. Corn germination was restored in test fire soil leached with 200 mm artificial rainwater. The results of this research contribute information regarding the potential impact of test fire soil from static test fires on crop production. Test fire soil inhibits germination and growth if deposited in the root zone, and even foliar application alters tissue composition. However, plant composition is not altered significantly in terms of feed criteria, and germination can be restored by irrigating the TFS. The effects of test fire soil are attributed to high levels of chloride that induce salt stress. Crop damage may be avoided by conducting static test fires after crops are harvested or providing extra irrigation to soil impacted with the TFS.

Research and experience has shown that vegetable oil can be processed, by transesterification, into a useable fuel for compression ignition engines. Earlier research examined using straight vegetable oil as a fuel, but found it to cause detrimental engine problems. Trial and error has shown that heating the vegetable oil prior to injection, is a viable option. A diesel vehicle engine was operated for over 188 hours or approximately 7,000 miles, using waste cooking oil as fuel. The longevity of the vehicle engine was limited by an undetermined engine failure. Using stationary testing, with no engine load and various power settings, engine emissions of several engines operating on waste cooking oil were compared to emissions from two other fuels, diesel and Biodiesel, and found to be very positive. Waste vegetable oil (WVO) had lower overall emissions than diesel and lower levels of nitrogen species than Biodiesel. Agricultural yield predictions estimate that currently only 5% and at most 20% of all diesel fuel needs can be met with vegetable oil. Currently WVO is a disposal problem. It is primarily used as a feedstock. WVO is not a commodity and has disposal fees associated with it. If WVO is used as a fuel, it would not only provide another source for disposal, but it may also increase the value of WVO making it a commodity instead of a disposal burden.

This thesis describes an experimental program covering the development of certain simple combustion chamber modifications to alleviate smoke emissions from the Allison T56 turboprop engines operated by the Royal Australian Air Force. The work includes a literature survey, smoke emission tests on two variants of the T56 engine, flow visualisation studies of the combustion system in a water tunnel and combustion rig tests of a standard combustor and four possible modifications. The rig tests showed that reductions in smoke emissions of 80% were possible by simple modifications that reduced the primary zone equivalence ratio and improved mixing in that zone.

<p>This report is the result of a diploma work made at Linköping University from August 2006 till September 2007 by Erik Lundin, under the guidance of Doctor Mike Andersson and Professor Anita Lloyd Spetz. Its purpose was to find suitable materials for the construction of an oxygen sensor. The hope was not to construct such a sensor, but to investigate materials that may be suitable in creating one. In the preparatory time period of the diploma work, different papers and books were studied in order to get a proper understanding of the sensor mechanism. During this period of time, a design proposal was made and the theory behind it is presented in this thesis. The main objective in this thesis has been to investigate the response of field effect devices to oxygen and other gases that are compounds in exhaust or flue gases. Devices were created by employing the materials which were investigated. Special material combinations were proposed for field effect devices suitable for oxygen detection by Doctor Mike Andersson. One material combination showed promising results for selective detection of the oxygen concentration in exhaust gases.</p> / This diploma work has been confidential