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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.
51

Determinação da saturação residual de óleo através da medida da variação da concentração de radônio na água de produção / Determination of residual oil saturation with the variation of the concentration of radon in water production

Pinto, Amenônia Maria Ferreira 20 August 2018 (has links)
Orientador: Elias Basile Tambourgi / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-20T02:06:50Z (GMT). No. of bitstreams: 1 Pinto_AmenoniaMariaFerreira_D.pdf: 8928817 bytes, checksum: adae0f7cc1ba62c41e7595bc4dd74788 (MD5) Previous issue date: 2012 / Resumo: A metodologia desenvolvida estabelece alternativas que possibilitam a quantificação do óleo estacionado no volume poroso dos reservatórios de petróleo. Foi admitido que, o conhecimento do coeficiente de partição do radônio entre o óleo e a água presentes no reservatório, viabilizará a determinação da Saturação Residual, levando-se em conta o aumento da quantidade de radônio na fase aquosa em relação à quantidade presente antes de ser iniciada a recuperação secundária, quando o óleo é expulso pela injeção de água. Foram executados testes, em escala de laboratório, em um corpo de prova composto por um meio poroso construído de forma a simular as características de um reservatório. O corpo de prova, elaborado a partir de uma rocha sedimentar de minério de urânio, foi acondicionado em um coreholder onde foram reproduzidas as etapas desde a formação até o esgotamento de um reservatório...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: A method has been developed for the quantification of the amount of petroleum remaining within the porous volume of oil reservoirs using radon as a natural tracer. The Oil Saturation is estimated, taking into account the partition coefficient of radon between the organic and aqueous phases in the reservoir is known and the increase in the amount of radon in the aqueous phase, relatively to the amount initially present is accounted for. The methodology has been tested in experiments carried in reduced laboratory scale. A porous medium block prepared in such a way to approximately reproduce the reservoir characteristics has been used in the tests. The block was built out of a sandstone rock containing uranium ore whose radon emanation rate allows precise measurements in small volume samples placed in a coreholder. The steps leading from the formation to the depletion of the reservoir have been simulated...Note: The complete abstract is available with the full electronic document / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química
52

Framing a New Nuclear Renaissance Through Environmental Competitiveness, Community Characteristics, and Cost Mitigation Through Passive Safety

Carless, Travis Seargeoh Emile 01 May 2018 (has links)
The nuclear power sector has a history of challenges with its relative competitiveness against other forms of electricity generation. The availability of low cost low natural gas, the Fukushima accident, and the cancellation of the AP1000 V.C. Summer project has caused a considerable role in ending the short lived “Nuclear Renaissance.” Historically, the nuclear industry has focused on direct cost reduction through construction, increasing installed capacity, and improving efficiencies to capacity factors in the 1990s and 2000s as ways to maintain competitiveness against other forms of energy generation. With renewables serving as an emerging low-carbon competitor, an added focus needs to be placed on indirect methods to increase the competitiveness of nuclear power. This thesis focuses on establishing pathways where nuclear power can be competitive with other forms of electricity generation given its advantages environmentally with Small Modular Reactors (SMRs), socioeconomically with legacy nuclear power plants, and through passive safety with SMRs. In Chapter 2, I estimate the life cycle GHG emissions and examine the cost of carbon abatement when nuclear is used to replace fossil fuels for the Westinghouse SMR (W-SMR) and AP1000. I created LCA models using past literature and Monte Carlo simulation to estimate the mean (and 90% confidence interval) life cycle GHG emissions of the W-SMR to be 7.4 g of CO2-eq/kwh (4.5 to 11.3 g of CO2-eq/kwh) and the AP1000 to be 7.6 g of CO2-eq/kwh (5.0 to 11.3 g of CO2-eq/kwh). Within the analysis I find that the estimated cost of carbon abatement with an AP1000 against coal and natural gas is $2/tonne of CO2-eq (-$13 to $26/tonne of CO2-eq) and $35/tonne of CO2-eq ($3 to $86/tonne of CO2-eq), respectively. In comparison, a W-SMR the cost of carbon abatement against coal and natural gas is $3/tonne of CO2- eq (-$15 to $28/tonne of CO2-eq) and $37/tonne of CO2-eq (-$1 to $90/tonne of CO2-eq), respectively. I conclude, with the exception of hydropower, the Westinghouse SMR design and the AP1000 have a smaller footprint than all other generation technologies including renewables. Assigning a cost to carbon for natural gas plant or implementing zero-emission incentives can improve the economic competitiveness of nuclear power through environmental competitiveness. The retirement of small and medium-scale coal power plants due the availability of natural gas can provide an opportunity for SMRs to replace that missing capacity. This trade-off between higher costs but lower GHG emissions demonstrates that depending on the value placed on carbon, SMR technology could be economically competitive with fossil fuel technologies Following my environmental competitiveness analysis, I shift towards investigating socioeconomic competitiveness of legacy large scale nuclear power plants compared to baseload coal and natural gas plants. In Chapter 3, I utilize ANOVA models, Tukey’s, and t-tests to explore the socioeconomic characteristics and disparities that exist within counties and communities that contain baseload power plants. My results indicate, relative to the home counties of nuclear plants, communities closer to nuclear plants have higher home values and incomes than those further away. Conversely, communities near coal and natural gas have incomes and home values that increase with distance from the plant. Communities near coal plants are typically either in less wealthy parts of the county or have a similar socioeconomic makeup as county. It can be suggested that equity issues regarding the community characteristics could be included in the discussion of converting existing power plants to use other fuel sources. Communities near power plants are not created equally and have different needs. While communities near nuclear power plants may benefit from the added tax base and absence of emissions, this is not the case for communities near coal and natural gas. With the impending retirement of large scale coal plants, the conversion of these plants to natural gas or small modular reactors presents an opportunity where negative environmental externalities can be reduced while also retaining some of the economic benefits. In Chapter 4, I present a model for estimating environmental dose exposure in a post-accident scenario to support scalable emergency planning zones (EPZs). The model includes calculating radionuclide inventory; estimating the impact decontamination factors from the AP1000, NUREG-6189, and EPRI’s Experimental Verification of Post-Accident iPWR Aerosol Behavior test will have on radioactivity within containment; and estimate dose exposure using atmospheric dispersion models. This work aims to compare historical decontamination factors with updated decontamination factors to outline the impact on containment radioactivity and dose exposure relative to the Environmental Protection Agency’s Protective Action Guide (PAG) limits. On average, I have found the AP1000, Surry, and iPWR produces 139, 153, and 104 curies/ft3 75 minutes after a LOCA. The iPWR produces less radioactivity per volume in containment than the AP1000 and Surry 84% and 96% of the time, respectively. The AP1000 produces less radioactivity per volume than Surry 68% of the time. On average, the AP1000, Surry, and iPWR produces 84,000, 106,000, and 7,000 curies/MWth 75 minutes after a LOCA. The lower bound 5 rem PAG limit is never exceeded for and does not exceeds the 1 rem lower PAG limit for whole body exposure at the 5-mile EPZ using the mean value. Considering this analysis uses a simple worst case Gaussian Plume model for atmospheric dispersion, the findings can be used to in conjunction with the State-of-the-Art Reactor Consequence Analyses (SOARCA) to provide accurate and realistic estimates for exposure. I believe this analysis can help to develop a regulatory basis for technology-neutral, risk-based approach to EPZs for iPWRs. Finally, in Chapter 5 I discuss historical challenges facing the nuclear industry, policy implications, and recommendations. These policy implications and recommendations serve as pathways to frame an new nuclear renaissance. I also recommend future work where I details opportunities for improvements to nuclear competitiveness. Ultimately, this thesis can help policy and decision makers that can improve competitiveness and minimize risk as it relates to the expansion of nuclear power sector.
53

Reduction of uranium-(VI) under microaerobic conditions using an indigenous mine consortium

Chabalala, Simphiwe 22 September 2011 (has links)
The utilisation of fossil fuels for energy worldwide depletes the natural reserves and at the same time releases billions of tonnes of carbon dioxide and other greenhouse gases into the atmosphere. In order to reverse the negative effects of this accumulation, i.e., global warming and climatic changes, countries around the world are now considering nuclear energy and other cleaner sources of energy as a substitute to the burning of fossil fuels. The deployment of the later technology has progressed slowly due to lack of public support. The general public and environmental lobbyists worry about the discharge of radioactive waste from nuclear power generation and accidents that have occurred in the nuclear power industry in the recent past. One of pollutants of concern is uranium which is discharged from the nuclear generation processes as the highly toxic uranium-6, (U(VI)). U(VI) coming from the reactors is radioactive as well as highly toxic to aquatic life forms. Biological treatment of metal pollutants is viewed as an environmentally friendly alternative to conventional physical/chemical treatment methods, especially in dilute solutions where physical/chemical methods may not be effective. Microbial processes may be applied both as in situ and/or ex situ processes. Microbial consortia, consisting of several species of microorganisms in the form of bioflocs for reducing/removing the pollutants have been used as they preserve the complex interrelationships that exist between species in the source. The results of this study demonstrate the potential of microbial U(VI) reduction as a possible replacement technology for physical/chemical processes currently in use in the nuclear industry. A detailed analysis of the biological reduction of uranium-(VI) was conducted and the following were the main findings of the study: (1) Background uranium concentration in soil from the mine was determined to be 168 mg/kg, a very high value compared to the typical concentration of uranium in natural soils; (2) Among six bacteria species isolated from a uranium mine in Limpopo, South Africa, three anaerobic species – Pantoea sp., Enterobacter sp. and Pseudomonas stutzeri – reduced U(VI) to U(VI) and facilitated the removal of the uranium species from solution. Based on batch studies and cell disruption studies, the laws governing microbial U(VI) reduction were determined and the kinetic parameters for U(VI) reduction were determined. The cultures in this study reduced uranium-U(VI) at a rate better than rates found in literature for other microorganisms. Reduction rates reported in this paper can be used to assess the applicability of bioreduction for uranium removal processes. / Dissertation (MSc)--University of Pretoria, 2011. / Chemical Engineering / unrestricted
54

Nocturnal atmospheric infrared radiation in Montreal.

Fuggle, Richard Francis. January 1971 (has links)
No description available.
55

Nuclear Vision: Canada, Modernity, and the Nuclear Age, 1942-1979

Cordeiro, Brandon Joseph January 2021 (has links)
This thesis proposes that the nuclear age offered high modernity and technological nationalism a central position in the making of modern Canada. The nuclear age influenced modern Canada’s social, economic, and political history and it did so by telling Canadians they were, essentially, a modern people governed by a modern state. From the 1940s to the end of the 1970s, Canada’s development of the nuclear industry reflected the pursuit of science and technology to create modern forms of energy production. Canadians were urged to see in nuclear power a way of remaining competitive in a changing global order. It offered them new industries at many stages of the nuclear cycle. The post-war era reflected a changing direction in the country’s central ideological direction – one defined since the 1840s by liberalism and a subordinate role in the British Empire. The creation of the Canadian nuclear cycle signified a transition to a new stage in which Canada, now imagined by some to be a nation, actively sought out modern forms of social and economic progress. Nuclear energy systems came to fruition at a moment when Canada was establishing new directions as a sovereign state vying for greater global political and economic influence on the global stage. This thesis argues that this pattern was no mere coincidence: this technological nationalism was the logical outcome of deep-seated tendencies. Yet, many citizens remained skeptical of the nuclear age’s possibilities. Although the federal government had established its nuclear cycle to develop the peaceful uses of atomic energy, its birth in the shadows of the Second World War and the Manhattan Project also provoked a widespread sense of discomfort. The dropping of the atomic bomb in 1945 solidified fears of nuclear energy long before the AECL built its first reactor on the shores of Lake Huron. Canadians en masse rejected the country’s participation in the development of nuclear weapons and, as Lester Pearson learned to his cost in 1963, were adamant that Canada should remain a nuclear-weapons-free nation. Successive governments in the 1950s and 1960s faced public backlash regarding Canada’s complicity in the stockpiling of nuclear arms, the production of uranium for American weapons, and its involvement in weapons tests. Born out of the peace movements and ecological movements of the 1960s, anti-nuclear groups emerged in the 1970s to oppose the nuclear industry. These groups shared members, ideas, and momentum, and the chasm between anti-war and environmental activism was progressively bridged as the 1970s proceeded. Both the anti-nuclear and anti-bomb activists were essential to challenging the path and direction of the Canadian nuclear system and its role in creating political and environmental uncertainty. Such fears remained a constant social reminder throughout the post-war era of the mutually assured destruction associated with atomic energy and the Cold War arms race. Indeed, Canada’s peaceful nuclear program did not always seem so peaceable, as activists in both camps argued more and more empathetically. Canada’s nationalistic pursuit of a nuclear modernity also entailed the quest of a narrow form of utopianism – one in which a future-oriented Canada provided greater social and economic freedoms under the aegis of liberal democracy. At the community level, nuclear energy symbolized the changing senses and sensibilities of living through modernity – the perception that the core structures of society were giving way to new social realities and that the relations of time and space were shifting. While nuclear energy symbolized the social and economic benefits of the cultural revolution of the nuclear age, it also aroused the concerns and fears about modernity. The conflicts between the pro- and anti-nuclear movements of the 1970s and 1980s were in many respects an extension of debates over high modernity and techno-nationalism. / Thesis / Candidate in Philosophy / This thesis explores the history of Canada’s nuclear age between 1942 and 1979 and examines how both Canadians and the state perceived the development of the country’s nuclear industry. It examines how Canada gained entrance into the nuclear club – joining the ranks of the Manhattan Project – its post-war developments in nuclear power, and the ways in which nuclear energy bolstered a form of nationalism predicated on technological prowess. The need to develop Canada’s nuclear industry reflected the larger social, political, and economic changes occurring in the post-war era. In many ways, the history of Canada’s nuclear age is the history of how societies act and react to modernity – the radical transformation of perceptions of space and time. This thesis examines that process of change and its influence on Canadians’ responses to the modern world around them.
56

Fuel Trajectory Analysis of Advanced Nuclear Energy Fuel Cycles and Systems

Presley, James January 1980 (has links)
<p> The unique features of the Interrupted Thorium Cycle owing to Pa-233 have been examined including possible implications for practical implementation of the cycle. Generalized trajectories for the fuel inventories of fusion-fission symbionts are derived through a comprehensive parametric analysis. The resultant formulations are then applied to a specific example. It is concluded that this formulation and analysis leads to more exact fissile and fusile fuel characterizations than suggested by conventional procedures. </p> / Thesis / Master of Engineering (MEngr)
57

Techno-Economic Analysis of a Biomass-Gas-and-Nuclear-to-Liquid Polygeneration Plant

Glover, Madison January 2022 (has links)
Due to the advancement of global warming internationally, increasing emphasis is being placed on the environmental accountability of everyone from countries to processes. This study presents novel research on the environmental impacts and economic trade-offs for a processes co-producing electricity, methanol, dimethyl ether (DME) and Fischer Tropsch (FT) fuels from different feedstock ratios of biomass, natural gas, and nuclear hydrogen generated through a CuCl cycle are analyzed for operation in Canada to produce transportation fuels. This study also considers the use of carbon capture and sequestration (CCS), the location of the plant in either Ontario and Alberta, and the input ratio of the feedstocks. This combination of carbonless heat and a “carbon neutral” biomass feedstock would contribute to the net reduction of greenhouse gas (GHG) emissions. In Part I of this work, the model for this BGNTL process was developed. This work expands on the model and evaluates the economics and environmental impacts this plant would have in both Ontario and Alberta based on their local costs, resource availability, and current electricity grid contributions. The analysis investigates the effectiveness of the emission reduction of the products and processes when compared to their cost. It is shown that an increase in the ratio of biomass to natural gas in feedstock, the use of a solid oxide fuel cell (SOFC), and the production of additional electricity while reducing the emissions of the process, increases the cost of CO2e avoided. The results show that the BGNTL concept can be an economically attractive way of reducing net transportation sector GHG emissions in both Ontario and Alberta in meaningful quantities. Optimal cases for both biofuel and FT fuel production contain a single output fuel production process, produce fuels over electricity where possible, and use a gas turbine (GT) for the electricity production that occurs. / Thesis / Master of Engineering (MEngr) / This paper examines a system producing a combination of transportation fuels including diesel, gasoline, methanol (MeOH), dimethyl ether (DME) and electricity from biomass, natural gas and hydrogen. The design of the system units used in the process was done in a previous study, this work expands on the design looking specifically at locating the plant in Ontario and Alberta for their raw resources, electricity grids, and current production methods of fuel. Variations of the plant are compared to each other and current fuel and electricity production with an aim of reducing the cost and emissions created while producing and using the fuels. It is found that increasing the amount of biomass used significantly reduces the emissions but does not create a competitive process due to how expensive it is. Results show that this type of system can decrease transportation sector emissions with a similar additional cost as other current alternatives.
58

A discriminant analysis of attitudes related to the nuclear power controversy in central and southwestern Ohio and northern Kentucky /

Girondi, Alfred Joseph January 1980 (has links)
No description available.
59

Atomic testing and population genetics: the AEC and the classical/balance controversy, 1946-1957

Seltzer, Michael William 16 December 2009 (has links)
The position of the United States Atomic Energy Commission (AEC) in the 1950s on the genetic hazards of fallout and radiation was a distortion of the views of geneticists from both sides of the classical/balance controversy, an intrascientific dispute among geneticists. In their attempt to demonstrate the harmlessness of test fallout, AEC officials argued that low levels of radiation were at worst genetically insignificant, and at best genetically beneficial. These arguments ran counter to the prevailing views of geneticists and represented a misleading attempt to deflect public and scientific criticism of the AEC’s atomic testing policies. Among the factors contributing to the distortion of views on genetic effects among the general public and government officials were the AEC’s unwavering commitment to atmospheric atomic testing; the failure to include geneticists in policy-making positions within the AEC and governmental radiation policy committees; confusion over the genetic effects to populations, as opposed to individuals; and the sharp polarization within the genetics community that resulted from the theoretical disagreements embodied in the classical/balance controversy, a dispute over the nature of genetic variation and evolutionary natural selection. / Master of Science
60

The design and construction of a laboratory facility for the measurement of reactor moderator parameters

Anthony, Lee Saunders January 1958 (has links)
A Sigma Pile was constructed to serve as a laboratory facility at V.P.I. Reproducible foil positions are possible with the positioning plates installed on the pile. Withdrawal of the two outer blocks in each foil channel is facilitated by a coupling mechanism. Five source positions permit operation with reduced harmonics. The neutron distribution in the pile was proven to be symmetric by horizontal and vertical traverses. By means of a diffusion length measurement, which gave an "L” of 54.5 ± 2 cm, and a Fermi Age measurement, which gave a "r” of 357 ± 5 cm², the parameters of the pile were shown to be in good agreement with published data on graphite. / Master of Science

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