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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.
1

The development of the eclipse process simulator and its application to the techno-economic assessment of fossil fuel based power generation technologies

Williams, Brian C. January 1994 (has links)
No description available.
2

The evolution of a range of salt glaze teapots

Meanley, Peter January 1998 (has links)
No description available.
3

Ceria based emission control catalysts

Daniell, Wayne January 1997 (has links)
No description available.
4

Winter composting of separated pig slurry solids and greenhouse gas emissions

Rutter, Jolene 12 April 2016 (has links)
One strategy to manage pig slurry is centrifugation and composting of the solids fraction to produce a value added product to distribute manure nutrients further from productions sites. This study determined turned windrow composting was suitable for processing slurry solids throughout winter. It was also the first attempt at combining automated chambers and a Fourier Transform Infrared spectroscopy analyzer to measure multiple gases during the composting process; the system proved capable but captured fluxes better if conducted in an area sheltered from wind. Straw and woodshavings were shown suitable as bulking materials for composting slurry solids, however, the lack of porosity provided by woodshavings created anaerobic conditions that doubled the greenhouse gas emissions compared to those of straw, 1,126 kg CO2-equivalent Mg-1 compared to 526 kg CO2-equivalent Mg-1. Either bulking material produced compost of quality for use in agricultural or soil blending applications and was free of manure pathogens. / May 2016
5

Hydric soil indicators, magnetic susceptibility and greenhouse gas emissions among differing land-uses of Prairie Pothole Region wetland soils

2013 April 1900 (has links)
Land-use change is prevalent across the Prairie Pothole Region (PPR) because of widespread agricultural expansion over the last century. Different land-use histories will affect the distributions of native vegetation and soil biogeochemistry of PPR wetlands. Furthermore, because native vegetation is partially required for wetland classification, supplementary methods are needed for proper wetland delineation. Accurate estimates of GHG emissions are required for correct climate change models; therefore proper investigation of contrasting land-use histories on GHG emissions is essential. This study focused on determining the effect that different land-use histories had on the expression of soil hydric features and magnetic susceptibility as well as examining interacting effects among contrasting land-use histories and biogeochemical controls of GHG emissions of PPR wetlands. To determine the differing effects of land-use histories on hydric soil indicators and magnetic susceptibility, fifteen ephemeral wetlands under differing land-uses (annually cultivated, restored grassland, seeded pasture and native grassland) were sampled to a depth of 1 m with samples collected every 10 cm. An upland pit was correspondingly sampled for each wetland. Soils were then analyzed for organic C, inorganic C, dithionite extractable Fe, particle size distributions, wet stable aggregate distributions and magnetic susceptibility at four different temperature treatments (room temperature, 100 °C, 300 °C and 500 °C). While some variables had observable difference among the land-uses (i.e. organic C, dithionite extractable Fe and magnetic susceptibility), the most pronounced differences were between the different pit positions (i.e. wetland pits vs. upland pits). The data was holistically analyzed through non-metric multidimensional scaling (NMDS) and position based differences were easily identified through this approach; however, only slight differences were present with respect to contrasting land-use histories. The controls of GHG emissions and their interactions were evaluated through two laboratory incubations (i.e. CH4 incubation and N2O incubation), with a factorial design using land-use history treatments as well as biogeochemical controls specific to each GHG (i.e. CH4: SO4- additions; N2O: water filled pore space [WFPS] treatments and NO3 - additions). Both incubations had the presence of interacting factors among the differing land-use histories. During the CH4 incubation, each land-use history responded oppositely to sulfate additions. During the N2O incubations, both WFPS treatments and NO3 - additions had additive effects on the emissions of N2O. Moreover, the presence of the interactions satisfied the objective of the incubation study. Overall it was determined that while land-use history significantly altered the response of GHG controls with respect to GHG emissions, it did not have strong effects in influencing hydric soil indicators and magnetic susceptibility values.
6

Mitigating Gas Emissions from Liquid Manure Storage Systems: Management Practices, Measurements and Modeling

Wood, Jeffrey 24 April 2013 (has links)
Livestock agriculture is a source of methane (CH4), nitrous oxide (N2O) and ammonia (NH3) emissions. A comprehensive approach aimed at mitigating these emissions is needed to reduce the environmental footprint of agriculture. This thesis examined three aspects of a comprehensive mitigation strategy which included: evaluating a management consideration, improving flux measurement techniques, and modeling emissions. The relationships between total solids (TS), gas emissions and surface crust dynamics were assessed. Diurnal and long–term CH4 and N2O flux variations were examined in the context of improving discrete sampling protocols. Finally, a mechanistic model that predicts CH4 emissions from manure slurries was evaluated. Over long–term storage, the crusts were not effective in mitigating total gas emissions because the slurries remained open to the atmosphere for a significant portion of the time. Total CH4 and NH3 emissions were related linearly to TS, while N2O exhibited a sigmoid response. The linear response to TS observed for CH4 and NH3 occurred despite varying crust conditions suggesting that the availability of substrates in slurries is the more important regulator of emissions over long–term storage. Diurnal CH4 and N2O flux variations were linked with the diurnal surface temperature (T0) cycle, with the strength of the relationship depending on surface crust conditions. An assessment of discrete sampling protocols revealed that sampling intervals should be ≤7 d. In terms of the timing, it is best to sample these gases when the T0 is closest to the daily mean, which would typically be before 0900 h or after 1700 h. A mechanistic model of CH4 emissions from slurries was evaluated. The model was most accurate during the first 47 d of storage, after which the accuracy decreased. However, total emissions estimated over 145 d were within –21.1 to 6.0% of measured emissions for slurries with TS 3.2%, 5.8% and 8.2%. Emissions were also modeled using the USEPA inventory method. There was relatively good agreement between the USEPA and mechanistic models, with relative percent differences ranging from 19.9 to 37.3%, which is encouraging from the standpoint of advancing greenhouse gas inventory methods. / Ontario Graduate Scholarship
7

Gaseous and particulate emissions.

Beebal, Nisha. January 2000 (has links)
The need to limit sulphur dioxide, nitrous oxides and particulate matter emissions from fossil fuel combustion processes is now a major factor in the design, construction and operation of plants. Over the past 5 to 10 years, most developed countries have introduced legislations to control these. emissions. This report was done to investigate emissions of sulphur dioxide (S02), nitrogen oxides (NOx) and particulate matter from coal fired power plants. S02 emissions contribute to an air pollution load that has been found to be linked to respiratory and heart problems. It increases the formation of acid precipitation, called acid rain. NOx oxides to nitrogen dioxide (N02). N02 acts as an irritant to the respiratory tract, alveoli of the lungs and causes chest pains. Toxic elements concentrate on fine particulate matter because of their high surface-area to volume ratio. These particles penetrate and settle onto the lung wall, leading to respiratory disorders and lung diseases. Due to the strict legislative requirements, flue gas detoxification processes were investigated. They include: • Wet scrubbing • Spray dry scrubbing • Dual-alkali • Well man-Lord • Activated carbon • Magnesium oxides • Selective catalytic recovery • Circulating fluidised bed combustion • Electromembrane desulphurisation A study was done to show the possible cost implications associated with the wet scrubbing, spray dry scrubbing, selective catalytic recovery, circulating fluidised bed and electromembrane desulphurisation process. A variety of methods were used to calculate cost, due to costs being difficult to obtain. Most of the information was based on European, Asian and American installations. The objective of this economic analysis was to compare the different technologies. Because of the assumptions used, costs were always "order of magnitude" estimates. Capital and operating costs were calculated for these technologies, but they can only be used as an indication of costs and to allow for comparisons between the technologies. The costs were converted using the January 2000 exchange rates. Due to this, costs may be more inflated than what would normally be expected due to equipment being purchased earlier than January 2000. Of the processes investigated, the circulating fluidised bed process was found to be the most economical. There is no inexpensive route for the removal of sulphur dioxide, nitrous oxides and particulate matter. The most suitable detoxification process will depend on the legislative requirements per country. South Africa is a signatory of the Montreal Protocol and the Framework for Climatic Change. Legislations for gaseous emissions were not considered a priority. Currently, Eskom's drive is to electrify townships rather than spend money on detoxification processes. However, future legislations may require more stringent control measures. / Thesis (M.Sc.Eng.)-University of Durban-Westville, 2000.
8

Reduced water consumption and related greenhouse gas emissions : A study of the effects of Uppsalahem’s watersavings campaign in 2013

Zisimopoulos, Dimitrios, Thor, Linnéa, Frisk, Malin January 2014 (has links)
The purpose of this project is to evaluate the effects of a campaign that Uppsalahem implemented in February 2013, in order to make their tenants consume less water. The result of the campaign is evaluated in terms of reduced water usage and reduced emissions of greenhouse gas related to the heating of the water through district heating. Four different residential areas in urban Uppsala, where Uppsalahem implemented their water saving campaign have been studied. All calculations are done in MATLAB. The results regarding water usage is presented in cubic meters and the greenhouse gas emissions are presented in terms of carbon dioxide equivalents. A sensitivity analysis of the data is performed in order to study natural occurring variances of water consumption over time. In order to determine which parameter has the greatest impact on reducing carbon dioxide emissions, a sensitivity analysis of the fuel mix used at the district heating power plant is made. The results show that there has been a reduction of water usage since after the campaign was implemented and the sensitivity analysis of the data indicates that there has been an especially large decrease in water consumption between the years 2012 and 2013. Further though, the results contain monthly irregularities in water usage in the different areas. This shows that the reduction of water consumption has not been temporally associated to the campaign, which indicates that the reduction might not be an effect of the campaign. Regarding carbon dioxide emissions, the sensitivity analysis indicates that the kind of fuel mix Vattenfall use at their district heating plant has a much greater impact than the individual water usage behaviors of the tenants.
9

Greenhouse gas emissions and climate policy in Florida's state and local governments (2000 to 2010)

Garren, Sandra Jo 04 April 2014 (has links)
The purpose of this dissertation is to assess the current state of climate policy and greenhouse gas (GHG) emission trends in the state Florida and its local governments. The research is guided by three research questions 1) What has been the policy response from state and local governments to the threat of climate change; 2) What were the GHG emission trends from 2000 to 2010 in Florida and its local governments and what were the drivers of change?; and, 3) what were the issues related to the data and methodologies to quantify GHG emissions at the local government level? Policymakers need accurate data and a framework by which to measure progress towards reduction targets and mitigation strategies aimed at reducing GHG emissions. To date, there has not been a comprehensive assessment in Florida despite the proliferation of reduction targets and action planning in state and local governments. Research was conducted to systematically catalogue climate policy at the state and specific actions at the local government level. Actions taken at the local government level included participation in one or more of eight climate networks and completion of a GHG inventory and/or climate action plan. A comprehensive GHG inventory was completed for the state (2000 through 2010) and for all 477 local governments (2000 and 2010). GHG emissions were summarized for total GHG emissions, per capita GHG emissions, per land area GHG emissions, and by sector (i.e., energy, transportation, industrial processes, agriculture, waste, carbon sequestration, and miscellaneous other categories). The ambitious 2007 policies of Governor Crist to curb state GHG emissions floundered once he left office and was replace by the new Governor Rick Scott. It was then left to local governments to respond to the threat of global warming with 117 of 477 local governments pledging to take action (as evidenced through participation in climate action networks). However, only a small minority actually tried to go beyond to complete a GHG inventory and develop a climate action plan. Of these, only two have conducted a follow-up GHG inventory with resultant increases of over 30 percent which falls far short of county-wide reduction targets of 20 percent. GHG emissions from the 39 local governments who undertook GHG inventories found increases in GHG emissions of 10 percent. GHG emissions in the state have increased by 14 percent from 2000 to 2010. In both 2000 and 2010, transportation and electricity consumption were the largest contributors of GHG emissions in both the state and its local governments. Industrial and agricultural emissions were also contributors but these emissions not equally distributed throughout local governments in Florida due to the location of these industries across the state. The rates of change from 2000 to 2010 were not equal in all categories. GHG emission increases were observed in the majority of categories but at different rates; however, reductions were observed in industrial sources and livestock and other agricultural sources. The research identifies drivers of GHG emission change in the state to include population size, Florida gross domestic product (FGDP), land use change, and national energy policies (i.e., natural gas over coal and increased fuel efficiency standards). When assessing methodologies for states and local governments, nine separate GHG methodologies were identified all of which used different approaches and categorical coverage. In addition, the procedures that are used may not be appropriate for the scale of a local jurisdiction due to problems associated with generalizing or averaging emissions data. Data availability at the state level is robust; however, readily-available data at the local government level for certain categories were deemed to be insufficient to avoid highly uncertain assumptions. Review of the completed GHG inventories indicates the use of different approaches makes comparisons between the published GHG emissions impossible. It is recommended that a standardized methodology and data collection framework be used for all local governments for more accurate comparisons and to assess the impacts of policy at a local government scale. While the local government GHG inventory required the use of some uncertain assumptions due to data limitations, such a framework was developed for this dissertation. The framework could be refined with more accurate data for future inventories and could also be adapted for other states.
10

Greenhouse gas emissions associated with different meat-free diets in Sweden

Baumann, Andreas January 2013 (has links)
The production of food is responsible for large share of the anthropogenic greenhouse gas emissions. There is a wide range of emissions associated with different food-groups. In particular the production of meat from ruminants causes higher emissions compared to plant-based food. This study compared two different types of meat-free diets (ovo-lacto-vegetarian and vegan) in Sweden and the emission of greenhouse gases that are connected to the aliment and beverages that are consumed in these diets. Dietary records were used to obtain real data on what food is consumed on a weekly basis. On average the food consumed by the vegan sample caused lower emissions that the food consumed by the vegetarian sample. The average vegan diet caused 591 kg CO2e per year whereas the average vegetarian diet caused 761 kg CO2e. The annual difference is thus 170 kg. These findings are in line with existing research although recent studies often used hypothetical diets instead of real data.

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