Dissertations / Theses on the topic 'Environmental degradation'
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Mohammadian, Mehrdad. "Environmental degradation of poly(ethyleneterephthalate)." Thesis, Manchester Metropolitan University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317574.
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The degradation of amorphous and orientated PET is investigated by several analytical methods. In this study, samples of both amorphous and orientated PET material were exposed to wet and dry soil, various humidities and temperature as well as UV irradiation. Results of accelerated ageing studies indicate that the amorphous sheet and biaxially orientated bottles degrade mainly due to de-esterification and oxidative chain scission due to their low crystallinity. At high temperatures (70-90) breakdown, as characterisedb y viscosity and chain scission measurements,is indicative of significant polymer deterioration. Breakdown is enhanced by increasing temperature, increasing relative humidity and UV irradiation. In this regard the polyester bottles are more stable than sheet due to a greater degree of orientation and hence higher degree of crystallinity. However, the rate of degradation is also a function of the surrounding environment. During the course of degradation, an increase in crystallinity was observed for both sheet and bottles. The rate of increase in crystallinity is initially rapid and is associated with plasticization by moisture and subsequent annealing. The dry conditions and UV irradiation cause negligible increase in crystallinity . An increase in the number of end groups was observed which is due to chain scission. Whilst the carboxyl and hydroxyl end groups were increased at the same rate asthermally degraded samples, the increase of carboxyl end groups for UV degraded samples was significantly higher than hydroxyl end groups. This increase is initially sharp and then more gradual with almost the same rate as hydroxyl end groups. A higher level of carboxyl end groups is due to the release of carbon dioxide and carbon monoxide mainly on the surface of the polymer. In this work two methods were used to introduce stability to the polymer. The first was preconditioning the polymer in an inert atmosphere for 48 hours at 600C which had a better effect for bottles This stabilizing effect was observed for both thermal degradation and UV irradiation of polyester materials. The second method was stabilizing polyester against UV irradiation by the incorporation of naphthalenea nd benzophenoned erivatives to the structure of the polyester. In this case the dihydroxybenzophenone showed the greatest stabilizing effect. Hydroperoxide formation during hydrolytic degradation is found to be both temperature and humidity dependent and appears to play a secondary role in thermal oxidation.
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El-Turki, Adel Abdulrazag. "Environmental degradation of construction materials." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310656.
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Chohan, Sukhvinder K. "Environmental degradation of polyethylene-based plastics." Thesis, Aston University, 1996. http://publications.aston.ac.uk/9675/.
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The criteria involved in the degradation of polyethylene-based degradable polymer samples have been investigated, with a view to obtaining a clearer mechanism of photo-biodegradation. The compatibility of degradable polymer samples during materials recycling was also studied. Commercial and laboratory prepared degradable polymer samples were oxidised in different environments and the oxidation products formed were studied using various analytical chromatographic and spectroscopic techniques such as HPLC, FT-IR and NMR. It was found that commercial degradable polymer samples which are based on the ECO systems, degrade predominantly via the Norrish II process, whereas the other degradable systems studied (starch-filled polyethylene systems, transition metal systems, including metal carboxylate based polyethylene systems and the photoantioxidant-activator systems) photodegrade essentially via the Norrish I process. In all cases, the major photoxidation products extracted from the degradable polymer samples were found to be carboxylic acids, although, in the polymer itself a mixture of carbonyl containing products such as esters, lactones, ketones and aldehydes was observed. The study also found that the formation of these hydrophilic carbonyl products causes surface swelling of the polymer, thus making bioerosion possible. It was thus concluded that environmental degradation of LDPE is a two step process, the initiation stage being oxidation of the polymer which gives rise to bioassimilable products, which are consequently bioeroded in the second stage, (the biodegradation step). Recycling of the degradable polymer samples as 10% homogeneous and heterogeneous blends was carried out using a single screw extruder (180°C and 210°C) and an internal mixer (190°C). The study showed that commercial degradable polymer samples may be recycled with a minimal loss in their properties.
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Kraverath, Scott C. "Reconciling environmental degradation and US national security." Thesis, Monterey, California. Naval Postgraduate School, 1994. http://hdl.handle.net/10945/28493.
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Approved for public release; distribution is unlimited.Although environmental concerns are nothing new, only recently have environmental issues been considered as having national security implications. Along with increased environmental awareness, the end of the Cold War has allowed security planners the latitude to reconcile and integrate nonmilitary concerns, including the environment, into what has traditionally been exclusively military oriented policy. This transition or broadening of national security policy to include these issues is proving slow and controversial. The nature of environmental issues is such that their inclusion into a national security framework is not an easy one. Because of the current and potential national security threats embodied in environmental degradation, a coherent environmental security policy needs to be formulated. Because of the scope, complexity, and unknown nature of environmental issues this has not yet been accomplished. By defining issues, setting criteria and examining individual cases of environmental degradation in the Western Hemisphere and case studies from Brazil and Mexico, this thesis attempts to facilitate the recognition of environmental degradation as a U.S. national security issue. The thesis seeks to provide a greater depth of understanding of environmental security issues and suggest methods by which solutions for environmental problems may be found
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Hua, Yongxia. "Modelling environmental degradation in adhesively bonded joints." Thesis, University of Surrey, 2006. http://epubs.surrey.ac.uk/804411/.
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Nwosu, Jonathan Emeka. "Industrial ecology: a panacea for environmental degradation." Thesis, Сумський державний університет, 2013. http://essuir.sumdu.edu.ua/handle/123456789/31070.
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Resource demand and environmental degradation have reached unsustainable levels. A sustainable future requires industrial systems’ attention and improvement. Industrial ecology springs from interests to integrate the notions of sustainability into environmental and economic systems (Allenby 1992). The fact is that the economy operates as an open system, drawing raw materials from the environment and returning vast amounts of unused by-products in the form of pollution and waste. The products that firms market are only a small portion of what their processes turn out; a significant portion of their output eventually leaves the economy as waste and returns to the environment in forms that may stress it unacceptably. (Ehrenfeld & Gertler, 1997). Increased economic output will still cause increased environmental harm. Thus, accomplishing economic growth and environmental protection simultaneously requires fundamentally new ways of examining and designing socioeconomic systems. One way to achieve this is through industrial ecology
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/31070
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Костюченко, Надія Миколаївна, Надежда Николаевна Костюченко, Nadiia Mykolaivna Kostiuchenko, and Kingsley Chukwuemeka Uzoigwe. "Environmental degradation in nigeria and management prospects." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/10363.
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Kinda, Somlanare Romuald. "Essays on environmental degradation and economic development." Thesis, Clermont-Ferrand 1, 2013. http://www.theses.fr/2013CLF10411/document.
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Cette thèse apporte un nouvel éclairage au débat sur la dégradation de l'environnement et le développement. Elle analyse les déterminants et les effets macroéconomiques de la dégradation de l'environnement. Elle est subdivisée en deux parties. La première partie analyse les effets de l'éducation et des institutions démocratiques sur la qualité de l'environnement. Le premier chapitre analyse le rôle de l'éducation dans la protection de l'environnement. Les résultats empiriques indiquent que l’effet dépend du niveau de développement. Contrairement à l’échantillon des pays en développement où elle n’a pas effet, l'éducation est source de pollution dans les pays développés. Cependant, cet effet est atténué en présence de bonnes institutions démocratiques. Le deuxième chapitre étudie l'impact des institutions démocratiques sur la qualité de l'environnement. Nous montrons qu´elles ont un effet direct et positif sur la qualité de l'environnement. Celui-Ci est plus élevé pour les polluants locaux que pour les polluants globaux. De plus, ce chapitre identifie des canaux indirects par lesquels l´amélioration de la démocratie dégrade l'environnement. En effet, en favorisant l´adoption de politiques de redistribution des revenus et de politiques économiques, la démocratie a un effet indirect et négatif sur la protection de l'environnement. La deuxième partie propose deux essais sur les effets du changement climatique et des politiques environnementales sur le développement. Le troisième chapitre met en évidence un effet négatif et significatif de la variabilité climatique sur la sécurité alimentaire dans les pays en développement. Cet effet apparait plus élevé dans les pays africains. Par ailleurs, cet effet est exacerbée dans les pays à conflit et ceux vulnérables aux chocs des prix des biens alimentaires. Le quatrième chapitre analyse l’effet de la similitude des politiques environnementales sur le commerce bilatéral. Contrairement aux études précédentes qui utilisent des indicateurs partiels de réglementation environnementale (indicateurs axés sur les moyens ou sur les résultats), nous construisons on un indicateur de politique environnementale révélé. Les résultats suggèrent que la similitude dans les politiques environnementales n'a pas d'effet sur les flux commerciaux bilatéraux. En outre les résultats ne dépendent ni du niveau de développement de pays partenaires ni des caractéristiques des biens exportés (biens manufacturés et biens primaires)This dissertation is a contribution to the debate on environmental degradation and development. It focuses on the determinants and macroeconomic effects of environmental degradation. It is structured in two parts. The first part analyses the effects of education and democratic institutions on environmental quality. The first chapter analyses the role of education in environmental quality. No evidence of an effect of education on carbon dioxide emissions. However, this effect depends crucially on the sample of countries according to their levels of development. While the effect remains insignificant in developing countries, education does matter for carbon dioxide emissions in developed ones. Moreover, when controlling for the quality of democratic institutions, the positive effect of education on carbon dioxide emissions is mitigated in developed countries while remaining insignificant in developing ones. The second chapter explores the effect of democratic institutions on environmental quality. We evidence that democratic institutions do have a direct and positive effect on environmental quality. This positive effect is stronger for local pollutants than for global ones. More interestingly, it identifies the indirect channels through which democracy affects environmental degradation. Indeed, by increasing people’s preferences for redistribution and economic policies, democratic institutions have indirect and negative effects on environmental protection through income inequality and investments. In the second part, the dissertation provides two essays on the effects of environmental policies and climate change on development. The third chapter investigates the effects of climatic variability on food security. The results show that climatic variability reduces food security in developing countries. The adverse effect is higher for African sub-Saharan countries than for other developing countries. Second, the negative effect of climatic variability on food security is exacerbated in countries facing conditions of conflict and is high for the countries that are vulnerable to food price shocks. The fourth chapter provides new evidence about the effect of a gap in environmental policies between trading partners on trade flow. While previous papers have used partial measures of environmental regulations (input-Oriented or output-Oriented indicators), we compute an index of a country’s environmental policy. Results suggest that a similarity in environmental policies has no effect on bilateral trade flows. Moreover results do not appear to be conditional on the level of development of the countries trading or on the characteristics of exported goods (manufactured goods and primary commodities)
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Galdi, Giulio. "Consequences of Environmental Degradation in Developing Countries." Doctoral thesis, Università degli studi di Trento, 2019. https://hdl.handle.net/11572/369108.
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Although climate change is a global phenomenon affecting populations from countries at varying stages of development, a few of its consequences gain significantly more salience for less developed countries, specifically. I focus on the adverse effects of environmental degradation for two main reasons. On the one hand, it is my impression that the increased vulnerability of less developed countries to adverse environmental degradation needs more attention by scholars (Biermann and Moeller, 2019). On the other hand, climate change is of the most pressing problems of our time, for which we have little time to act (IPCC, 2018) and whose consequences weight on the shoulders of many future generations. In other terms, the environment is deteriorating fast, and not only this is occurring faster in developing countries than in industrialised ones, the former are also less capable to protect against it for institutional, technological, and financial reasons (Barbier, 2010; Blaikie, 2016).
The asymmetry of environmental deterioration and of its effects is observable in many indicators. For instance, soil erosion is affecting ever larger areas, most of them in developing countries, whose institutions are not able or willing to intervene (Blaikie, 2016). Soil erosion mainly affects farmers and their productivity, but in developing countries they do not have the financial and technological means to defend themselves (Barbier, 2010; Blaikie, 2016), which induces some of them to resort to migration (when possible) (Blaikie 2016). Farmers trying to adapt to the erosion of soil may adopt coping strategies that endanger the sustainability of proximate water basins, fisheries (for instance, see Dejen et al., 2017) and of forestry (see Wondie, 2010). These practices ultimately undermine the sustainable extraction of natural resources and thus the long term productivity of the related activities. In these few introductory lines, I touched upon the issues I decided to investigate in this doctoral thesis: adaptation strategies and their possible negative side effects, inequality in the consequences of and in the means to face environmental degradation, and the long term effects of the latter on productivity. In my opinion, these are three very relevant pathways connecting environmental degradation to hindrances and obstacles to sustainable development of less developed countries. In the three chapters constituting the thesis, I investigate the economic dimensions of the problems above mentioned.
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Galdi, Giulio. "Consequences of Environmental Degradation in Developing Countries." Doctoral thesis, University of Trento, 2019. http://eprints-phd.biblio.unitn.it/3611/1/Consequences_of_Environmental_Degradation_on_Developing_Countries.pdf.
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Although climate change is a global phenomenon affecting populations from countries at varying stages of development, a few of its consequences gain significantly more salience for less developed countries, specifically. I focus on the adverse effects of environmental degradation for two main reasons. On the one hand, it is my impression that the increased vulnerability of less developed countries to adverse environmental degradation needs more attention by scholars (Biermann and Moeller, 2019). On the other hand, climate change is of the most pressing problems of our time, for which we have little time to act (IPCC, 2018) and whose consequences weight on the shoulders of many future generations. In other terms, the environment is deteriorating fast, and not only this is occurring faster in developing countries than in industrialised ones, the former are also less capable to protect against it for institutional, technological, and financial reasons (Barbier, 2010; Blaikie, 2016).
The asymmetry of environmental deterioration and of its effects is observable in many indicators. For instance, soil erosion is affecting ever larger areas, most of them in developing countries, whose institutions are not able or willing to intervene (Blaikie, 2016). Soil erosion mainly affects farmers and their productivity, but in developing countries they do not have the financial and technological means to defend themselves (Barbier, 2010; Blaikie, 2016), which induces some of them to resort to migration (when possible) (Blaikie 2016). Farmers trying to adapt to the erosion of soil may adopt coping strategies that endanger the sustainability of proximate water basins, fisheries (for instance, see Dejen et al., 2017) and of forestry (see Wondie, 2010). These practices ultimately undermine the sustainable extraction of natural resources and thus the long term productivity of the related activities. In these few introductory lines, I touched upon the issues I decided to investigate in this doctoral thesis: adaptation strategies and their possible negative side effects, inequality in the consequences of and in the means to face environmental degradation, and the long term effects of the latter on productivity. In my opinion, these are three very relevant pathways connecting environmental degradation to hindrances and obstacles to sustainable development of less developed countries. In the three chapters constituting the thesis, I investigate the economic dimensions of the problems above mentioned.
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Evangelista, Sarah. "Microbial degradation of chlorophenoxy acids." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32352.
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Clofibric acid, a pharmaceutical, and MCPP and MCPA, two herbicides, are structurally similar compounds. They are classified as chlorophenoxy acids and are found as organic contaminants in the aquatic environment. Their presence and fate in the environment has been of great concern. Microorganisms are ubiquitous in the environment and can play an important role in influencing the persistence of these contaminants because of their capacity to degrade them. Comparative biodegradation studies of the three compounds were performed using axenic cultures of bacteria. All microorganisms tested on clofibric acid were incapable of degrading it save for Rhodococcus rhodochrous which, instead of degrading it, transformed clofibric acid into its ethyl ester, ethyl clofibrate. MCPP and MCPA were degraded by Sphingomonas herbicidovorans at approximately the same rate, however, different metabolites were observed depending on the set of conditions used. More specifically, different biomass concentrations used in the experiments altered the emergence pattern of the metabolites seen during the degradation. Despite the fact that Sphingomonas herbicidovorans was capable of degrading MCPP and MCPA within a couple of days, results indicated that it was incapable of degrading clofibric acid under the same conditions. This suggests that the recalcitrance of clofibric acid is due to the additional methyl group adjacent to the ether bond.L'acide clofibrique, un produit pharmaceutique, le MCPP et le MCPA, deux herbicides, sont des composés similaires en structure. Ils font tous partie du groupe des acides chlorophénoxiques. La présence de ces contaminants organiques et leur sort dans l'environnement aquatique sont maintenant des sujets de préoccupations. Les microorganismes sont omniprésents dans l'environnement et jouent un grand rôle dans la possible dégradation de ces contaminants. La présente étude, portant sur leur biodégradation, a été menée avec des cultures pures. Tous les microorganismes testés furent incapables de dégrader l'acide clofibrique, à l'execption de la bactérie Rhodococcus rhodochrous qui menait à sa transformation en clofibrate, son ester éthylique. Le MCPP et le MCPA furent dégradés par la bactérie Sphingomonas herbicidovorans. Malgré le fait que leur taux de dégradation était similaires, les métabolites observés étaient différents selon le composé et les conditions employés. La concentration de biomasse employée pour débuter les expériences influençait les tendances d'apparition des métabolites. Malgré le fait que Sphingomonas herbicidovorans pouvait dégrader le MCPP et le MCPA en quelques jours, les résultats indiquent que ces bactéries sont incapables de degrader l'acide clofibrique dans les mêmes conditions. Cela suggère que la récalcitrance à la biodégradation de l'acide clofibrique est liée à la présence d'un groupe méthyle supplémentaire adjacent au lien éther.
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Tochterman, Thomas L. "Environmental Leadership: Exploring Environmental Dissonance Involving Natural Resource Consumption and Ecosystem Degradation." ScholarWorks, 2016. https://scholarworks.waldenu.edu/dissertations/2624.
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As the corporate world, communities, and individuals become more globalized and demands on natural resources increase, a new emphasis on environmental leadership including a new pragmatic environmental ethos is needed to meet certain basic human needs of future generations. The research problem addressed in this study was the lack of knowledge concerning how environmental cognitive dissonance influences consumption practices related to inefficient resource utilization and ecosystem degradation. The purpose of this study was to provide an understanding of the breadth and depth of environmental cognitive dissonance among visitors to the Kruger National Park in South Africa. The research questions addressed the development, manifestation, and mitigation of environmental cognitive dissonance. This qualitative case study was designed for a purposeful sample of 12 participants visiting the Kruger National Park, South Africa. Data were collected via structured interviews, field observations, and questionnaires, and then were analyzed using a data spiral and cross case analysis. The dominant findings indicated that (a) awareness of personal values, culture, and perceptions of the environment were responsible for basic attitudes regarding the environment and consumption; (b) wasteful habits, excessive consumption, and market influences were juxtaposed with nostalgic/episodic memories and deep thoughts about personal consumptive habits; and (c) an interactive multisensory experience in a pristine and wild environment changed perceptions and values regarding ecosystems and ecosystem preservation. The results of this study could help stewards of natural resources develop a new understanding of consumptive behavior and a new consumer ethos of stewardship and environmental leadership, one that inspires healthy and sustainable ecosystems.
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Mloszewski, Aleksandra. "Environmental and microstructural controls of short-term shell degradation in temperate, macrotidal environments." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40807.
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Depositional conditions early post-mortem influence net shell alteration prior to fossilization. This study assesses the progressive degradation of experimentally deployed Mytilus edulis shells and natural aragonite crystals during 13 months at and 10 - 20 cm below the sediment surface in High- and Mid-Marsh Salt Marsh Ponds, a Beach and a Cove (Bay of Fundy, NB, Canada). Changes in net weight, macroscopic, and microstructural features are examined in the context of environmental conditions. Results show that: 1) early degradation processes act very quickly, causing significant changes in shell condition within 13 months post-deposition. 2) The sloughing off of shell crystallites loosened by maceration, bioerosion and maceration, in order of importance, dominate shell degradation in the study environments. 3) Dissolution contributes relatively little to the overall taphonomic signature during early shell degradation.L’état de préservation des coquilles d’organismes marins dépend directement des conditions environnementales dans lesquelles elles se dégradent. Cette étude a pour but de déterminer les conditions de dégradation progressive de coquillages (Mytilus edulis) et de cristaux abiotiques d’aragonite déployés à l’interface eau-sédiment ainsi qu’enfouis (à 10-20 cm) durant treize mois, dans les zones haute et moyenne d’un marais salant, une plage et une crique de la Baie de Fundy (NB, Canada). Les changements macroscopiques, microscopiques et de masse sont discutés relativement aux conditions environnementales. Nos résultats montrent que: 1) la dégradation et les processus agissent très tôt après la déposition, et produisent des changement d’état significatifs en deçà de 13 mois post-mortem. 2) Dans les environments ci-dessus, la mue des tablettes de nacre de la surface de la coquille est le processus le plus efficace, suivi par la bioérosion, et la macération. 3) La dissolution joue un rôle secondaire durant la dégradation précoce des coquillages.
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Reynolds, Tom George 1972. "Accelerated tests of environmental degradation in composite materials." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/28202.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1998.Includes bibliographical references (leaves 143-147).
High temperature polymer matrix composites are key candidates for the structural components of proposed supersonic transport aircraft. The operational environment of these vehicles exposes the airframe to harsh conditions, including temperature extremes and moisture. These environments have been seen to cause visible damage in polymer matrix composites in timescales much less than the lifetime of the vehicle. Therefore, there is an urgent requirement for accelerated testing of the key components of the environment. A first step to this goal is to identify the components of the environment responsible for the damage. The effects of a realistic moisture and thermal environment on two high temperature polymer matrix composites (PETI-5 and PIXA-M) have been investigated in this work. An extensive test program was developed to test the response of the materials to this baseline environment and its individual components: time at moisture, moisture cycling, time at temperature and thermal cycling. Mechanism-based models were used to design accelerated moisture cycles and accelerated thermal cycles in an attempt to speed up the response to these environmental factors. These accelerated cycles were also used in the test program. The results showed visible damage in the form of cracking in both retrials. The PIXA-M material was found to show more damage than the PETI-5. Cracking was confined to a thin layer of material next to the exposed edge. This suggests that the environmental exposure is reducing the effective fracture toughness of the material in this layer more than in the interior. Analysis suggests that this layer is exposed to more of the environmental components and fluctuations than the material in the interior. The individual components of time at moisture and thermal cycling were seen to cause cracking, while time at temperature did not, and moisture cycling did not appear to accelerate moisture damage. The combined environments in the baseline cycle caused more damage than any one component of the cycle on its own. Evidence points to the combined effects of time at moisture and thermal cycling as being the dominant parameters causing damage, while moisture cycling controls the extent of the damaged region. Although the designed accelerated cycles were not successful in accelerating the damage from the baseline cycle, they were instrumental in establishing what were the dominant parameters. It is suggested that a promising way of accelerating the damage observed under the realistic conditions is by combining an iso moisture environment with a cyclical stress environment, which can be achieved either thermally or mechanically.
by Tom George Reynolds.
S.M.
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Lambert, Scott. "Environmental risk of polymers and their degradation products." Thesis, University of York, 2013. http://etheses.whiterose.ac.uk/4194/.
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Polymer-based materials are found everywhere in the environment, but their impacts are yet to be fully understood. The degradation of different polymer types has been extensively investigated under specific laboratory conditions. However, only limited data are available on their degradation under environmentally relevant conditions, where a number of processes are assessed at once. This thesis therefore describes a series of outdoor aquatic microcosm studies and laboratory experiments to investigate the degradation of a case study polymer (natural rubber latex), to characterise the formation of degradation products, and to assess the effects these may have on aquatic organisms. The outdoor microcosm studies showed that the exclusion of light and material thickness had a greater influence on degradation rate than media pH and sample movement. Analysis of the degradation solutions demonstrated that when the latex polymer degraded, there was an increase in the formation of microscopic latex particles; zinc (used to speed up the rate of curing processes) migrated from the latex polymer into the test solutions; and a mixture of dissolved substances that are potentially oxidised latex oligomers with additives residues were formed. Further analyses also showed that the atmosphere is a receiving environmental compartment for polymer degradates though the identification of a range of volatile substances produced during the degradation process. Laboratory experiments were then conducted to investigate the direct toxicity of the formed degradate mixtures, using two freshwater organisms with different life cycle traits, the water column crustacean Daphnia magna and the sediment-dwelling larvae of Chironomus riparius. The results suggest that, to the organisms tested, there is limited environmental risk associated with latex degradation products. Overall, environments receiving polymer debris are potentially exposed to a mixture of compounds that include the parent polymer, fragmented particles, leached additives, and subsequent degradation products; however at environmentally relevant concentrations this latex degradates pose little risk.
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Gangula, Srilatha. "Degradation of Chlorophenols in Swine Waste." TopSCHOLAR®, 2010. http://digitalcommons.wku.edu/theses/151.
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Naturally occurring plant derived phenols can be degraded through bacteria in swine waste. Chlorinated phenols, which are not naturally present in the environment, are toxic and generated from industrial activities as such petrochemical, pharmaceutical, plastic, rubber, pesticide, iron, steel, paper production, coal conversion, wood preserving, and cellulose bleaching. Large scale coal gasification and carbonization plants are another source of chlorinated phenols. Although not normally present in the environment, chlorinated phenols are structurally similar to many plant derived phenolics.
It is our hypothesis that bacteria located in swine wastes may also have the ability to degrade chlorinated phenols. Identifying situations (and organisms) in which degradation of pollutants occurs is important field of research.
Experimental work was focused on measuring the degradation of seven chlorinated phenols in swine waste using solid-phase micro-extraction (SPME) and gas chromatography(GC). Microbes in the waste perform respiration or fermentation to obtain the energy they need to carry out their life processes. Fermentation is a process in which electrons are transferred from one organic substrate to another and which results in incomplete degradation of organic compounds. Anaerobic respiration is a process in which organic substrates are degraded completely to CO2, but using substances other than oxygen as the terminal electron acceptor (such as Fe(III), NO3- or SO42-). Anaerobic respiration using these alternative electron acceptors provides an easier pathway for degradation of aromatics than fermentation alone. Usually the abundance of these electron acceptors in waste is low since microbes consume them readily and thus they must be added to the mixture. Our work focused on development of methods for the quantification of chlorinated phenols in swine wastes and results of bioremediation research.
In this study, chlorophenols were extracted by SPME and analysed by GC. This research project mainly focused on the anaerobic degradation of chlorophenols in swine waste. It was observed that the decreased concentration of the chlorophenols was likely due to partitioning of the chlorophenols to solids, sticking to glass bottles and by bacteria present in the swine waste.
In summary, it was observed that by ANOVA and gas production analysis 2,6-dichlorophenol and 2,4,5-trichlorophenol were likely to be degraded by bacteria present in swine waste.
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Sharma, Ram Prasad. "A study in environmental degradation in the Darjeeling hill areas." Thesis, University of North Bengal, 2012. http://hdl.handle.net/123456789/1538.
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Warner, Stephanie D. "Photochemical degradation of selected polycyclic aromatic compounds." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84446.
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Polycyclic aromatic hydrocarbons and many of their derivatives are considered to be ubiquitous environmental pollutants, which often exhibit mutagenic and/or carcinogenic activity. In the atmosphere, photolysis is generally considered to be the dominant degradation pathway for these pollutants. The photochemical behaviours of benzo(a)pyrene, benzo(b)fluoranthene and benzo(k)fluoranthene have been examined in the laboratory. This study was complemented by an analysis of ambient air samples collected in the vicinity of a Horizontal Stud Soderberg aluminum smelter in Beauharnois, Quebec. Benzo(a)pyrene is much more reactive in the presence of light when compared to the fluoranthene compounds. The products were identified as the 1,6-, 3,6- and 6,12-benzo(a)pyrenediones. An analysis of the ambient air samples revealed the prevalence of benzo(b)fluoranthene in the emissions from the aluminum smelter. Its relatively high abundance and resistance to degradation indicates that it will be a suitable indicator to represent total polycyclic aromatic hydrocarbon levels at the smelter. The photochemical behaviour of a series of nitropolycyclic aromatic hydrocarbons has also been investigated. The photoreactivity of these compounds in solution and adsorbed onto a surface has previously been associated with the torsion angle of the nitro group with respect to the aromatic moiety. Initially, through a combination of spectroscopic techniques and semi-empirical calculations, the orientation of the nitro group in each compound was determined. Solution studies were inconclusive in determining the role of the torsion angle of the nitro group in influencing the photochemical degradation. However, when the compounds were adsorbed onto a surface, no relationship could be established between photoreactivity and the orientation. The stability of these compounds was also examined during the sampling process. In an effort to further examine the relationship between th
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Chhetri, (. Karki ). A. B. "Environmental degradation in Sikkim with special reference to tourism." Thesis, University of North Bengal, 2005. http://hdl.handle.net/123456789/1341.
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Kasker, Muhammad Sameer. "Global environmental governance: is there a need for a global environmental organisation?" University of the Western Cape, 2014. http://hdl.handle.net/11394/4416.
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Magister Legum - LLMIn order to address the challenge of global environmental degradation and natural resource depletion, a complex and multi-layered environmental governance structure has materialised over the past few decades. There is widespread agreement that the current international environmental regime is too complex and inadequate to effectively address global environmental challenges. Thus, in order to control the threat of environmental degradation, many countries, authors, commentators and academics alike have opined that one centralised body be created for the effective control and governance of environmental matters on an international level. Governance is not the same as government. It includes the actions of the state and, in addition, encompasses actors such as communities, businesses, and Non-Governmental Organisations (hereafter referred to as NGOs). Within the context of the evolution of global environmental politics and policy, the end goal of global environmental governance is to improve the state of the environment and to eventually lead to the broader goal of sustainable development. The efficacy of global environmental governance will ultimately depend on implementation at global and domestic levels. National implementation is the ultimate key, both to the efficacy of the GEG system and to meaningful environmental improvements. In the following composition, I will critically analyse the concept of a Global Environmental Organisation (hereafter referred to as a GEO) and discuss whether the formation of such an establishment is indeed necessary to handle environmental matters on an international scale.
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Nalin, Laura. "Degradation of environmental protection coatings for gas turbine materials." Thesis, Cranfield University, 2008. http://dspace.lib.cranfield.ac.uk/handle/1826/4522.
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Nowadays, problems of component materials reliability in gas and oil-fired gas turbines focus on assessing the potential behaviour of commonly employed coatings, in order to avoid expensive and unpredictable failure in service and producing new materials whose performance meets life time and manufacturing/ repairing requirements. This MPhil project has investigated the oxidative and corrosive degradation mechanisms for some of the alloy/coatings systems (CMSX-4, CMSX-4/ RT22, CMSX-4/ CN91 and CMSX-4/ “LCO22”), which are currently used for turbines blades and vanes, in order to achieve a better knowledge of materials behaviour and to improve models for the prediction of turbine components’ lives. To achieve this target the study has made use of realistic simulations of turbine exposure conditions in combined with pre- and post-exposure metrology of bar shape materials samples, while optical microscopy has been applied to describe the microstructural evolution during the exposure and the products of the degradation for the hot corrosion. For high temperature oxidation, over extended periods of time (up to 10,000 hours), the research has allowed to describe the morphological changes in respect of the exposure time and temperature and to determine the oxidation kinetics experienced by the alloy and coatings. A model has been presented for predicting θ- α-Al2O3 growth. Moreover, using NASA COSP spalling model, with rate constants values coming from this study, a comparison between experimental mass change data and prediction has been shown. The hot corrosion study has provided new quantitative metal loss data and observations that extend/validate an existing model for materials life prediction, based on defining the severity of the corrosion conditions through measures of gas composition and contaminant deposition flux.
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Horn, Owen. "Environmental Contamination by Metabolites of Microbial Degradation of Plasticizers." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=92140.
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Earlier work with pure cultures has shown that the interaction of microbes with plasticizers leads to the formation ofmetabolites including 2-ethylhexanol and 2ethylhexanoic acid that resist further degradation. The same studies have shown that these compounds exhibit acute toxicity. This work has shown that the ability of soil micro-organisms to produce these metabolites from the degradation ofplasticizers is a general phenomenon. It was also found that the ability of soil organisms to degrade 2ethylhexanoic acid does not seem to be as common. Taken together, it would be expected that partial de gradation products of plasticizers should be observed in the environment. This was confirmed in a variety of environmental samples including sediments, surface waters, tap water, and fresh precipitation. Thus, even in a complex ecosystem, when plasticizers were degraded, the breakdown is not complete and significant amounts of2-ethylhexanoic acid and 2-ethylhexanol were observed. Since it is already weIl established that plasticizers are ubiquitous in the environment, it is expected that their recalcitrant metabolites will also be ubiquitous. This is a concem because, while the plasticizers do not exhibit acute toxicity, their metabolites do.Il a été démontré, lors d'études précédentes faites avec des cultures pures, que l'intéraction de microbes avec des plastifiants mène à la formation de certains métabolites résistant à une dégradation ultérieure, incluant le 2-éthylhexanol ainsi que l'acide 2éthylhexanoïque. Ces mêmes études ont aussi démontré que ces composés ont une toxicité aigue. Le présent ouvrage a démontré que l'habileté à produire ces métabolites à partir de la dégradation de plastifiants est un phénomène généralisé chez les microorganismes provenants des sols. Il a aussi été démontré que l 'habileté de ces microorganismes à dégrader l'acide 2-éthylhexanoïque ne semble pas être aussi répandue. À partir de ces observations, il semble que les produits de la dégradation partielle des plastifiants devraient être observables dans l'environnement. Ceci a été confirmé dans un éventail d'échantillons environnementaux incluant des sédiments, des eaux de surface, des eaux potables municipales et des précipitations. Donc même dans un écosystème complexe, lorsque les plastifiants sont dégradés, la décomposition n'est pas complète et des quantités notables d'acide 2-éthylhexanoïque et de 2-éthylhexanol sont observées. Puisqu'il a déjà été établi que les plastifiants sont omniprésents dans l'environnement, il est prévu que leurs métabolites récalcitrants y seront aussi omniprésents. Ceci présente un intérêt majeur puisque ces métabolites, contrairement aux plastifiants, possèdent une toxicité aigue fr
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Lertzman, Renee Aron. "The myth of apathy : psychosocial dimensions of environmental degradation." Thesis, Cardiff University, 2010. http://orca.cf.ac.uk/55458/.
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This thesis presents a psychosocial investigation into environmental subjectivity, through the lens of the myth of apathy. The central argument is for the acknowledgement of unconscious processes, in particular defence mechanisms, and themes of loss, mourning and ambivalence, in how environmental issues are perceived, experienced and responded to. The research draws from qualitative fieldwork in Green Bay, Wisconsin in 2007, involving three in-depth interviews with ten participants selected through the use of an online survey. Surveys were sent out to 1067 residents in Green Bay, 163 responded. The interviews were conducted using a dialogic, relational interview approach, and the analysis based on psychoanalytic qualitative research methods. The analysis centres on several core themes as emerging in the data and in the context of industry in Green Bay: loss, mourning and melancholia; ambivalence and splitting; and concern, care and reparation. The data analysis presents two case studies and four analytic thematic chapters. Based on psychoanalytic clinical work on reparation, the thesis presents a case for the incorporation of creativity and concern in the practice of environmental communications and advocacy, and critiques the concept of apathy as based on assumptions regarding a lack of concern or care. Further the thesis critiques the concepts of the gap between values and practices, or between concern and action, and advocates an appreciation for the complex dilemmas, struggles, and contradictions that may arise from environmental issues and degradation. The thesis aims to contribute to the field and practice of environmental communications and policy, in addressing unconscious dimensions and the need to incorporate affective elements of environmental degradation in addition to attitudes, values and behaviour.
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Ukpebor, Justina. "Investigating the environmental degradation and toxicity of organophosphorus pesticides." Thesis, Lancaster University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.587503.
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Organophosphorus insecticides (OPs) are some of the most widely used pesticides in the world and are present in a variety of diverse environments including remote areas well away from known usage areas. Unlike their older organochlorine counterparts, OPs are generally more polar, exhibit higher solubility in water and experience shorter environmental half-lives, but their ongoing use and concerns over their toxicity, particularly through the rise of transformation products, to non-target organisms requires research into factors which infuence their environmental transformation and toxicity. This thesis focuses on the environmental degradation, fate and toxicity of selected OPs under novel or non- standard environmental conditions. "Non-standard" is defined as conditions which deviate from current chemical fate testing environments provided by the US-EPA, EU Technical Guidance Documents and OECD Fate testing guidelines, used for pesticide/chemical risk assessment purposes. An analytical method was developed utilising both GC-MS (El) and LC- MS (ESI-Ion Trap) techniques to qualify/quantify thirteen OPs commonly reported in environmental media. A solid-phase extraction technique was developed and optimised for aquatic samples that yielded excellent recoveries (~70-110%) for OP fortified field water and the method was successfully applied to examine OPs artificially doped into a melting snowpack in northern Sweden as part of wider programme examining chemical fate in northern catchments. The rationale for examining OPs in snow was due to recent evidence that shows their accumulation in ice-cores taken in the high Arctic. OP chemicals showed rapid percolation (within 24 h) from a surface snow layer to the deeper pack and were also present in meltwater collected at the base of the snowpack, implying that a significant proportion of accumulated OPs were likely to be available within meltwater runoff during spring. Failure to recover the mass of OPs initially spiked into the snow implies that volatilisation may also be a loss process during snow ageing over relatively short time periods. The LC-MS(Ion trap) method, while selective. - particularly in MS/MS mode (with product ions used to qualify OPs) - was not as sensitive as GC-MS, with method detection limits in the umolar range compared to nmolar quantities for the GC. The LC-MS(Ion trap) was therefore unsuitable for trace-level determination of OPs in environmental samples. Using these analytical methods, laboratory-based studies were undertaken to understand the degradation/loss of selected OPs (fenitrothion and diazinon) when subject to simulated sunlight (using an Atlas Suntest chamber fitted with a UV-filtered Xenon arc lamp) in various aqueous solutions (to resemble field water) and on crop/lettuce (lactuca sativa) surfaces under different environmental conditions. For the aqueous solutions, photodegradation was examined in the presence of nitrate (N03-), carbonate (COl-), and dissolved organic carbon (DOC - as fulvic acid) at concentrations typically found in natural waters. Fenitrothion absorbs light within the solar spectrum, whereas diazinon does not (I."max ~247 nm). Both chemicals were found to show enhanced photodegradation in the presence of N03-, and to a lesser extent col, presumably due to the light- induced formation of aqueous hydroxyl radicals (OH) which attack organic solutes. For fenitrothion, rates of photochemical degradation (conforming to pseudo-first order kinetics) increased by >2-fold in the presence of N03- compared to the direct photolysis rate measured in pure (MilliQ) water. Similarly, for diazinon, degradation was observed in the constituent-based solutions but not in MilliQ water. The rate constant observed in the presence ofN03- was 0.084 hr" 1, which was not statistically different than the photolysis rate of fenitrothion in MilliQ water (0.072 hr-1), highlighting the importance of indirect photochemical processes on chemical loss, even for diazinon. It is recommended that use of dissolved constituents be incorporated into aquatic photochemical fate testing guidelines for pesticides, as current testing procedures, while recommending the use of pH buffered solutions, will currently overestimate pesticide longevity in most sunlit natural waters. The photolysis of fenitrothion was also examined on tetfuie leaf surfaces and a pesticide application and extraction method was developed that provided a high degree of reproducibility (%RSD = 2.03) necessary for leaf photolysis experiments. Fenitrothion photolysis was carefully examined in aqueous solutions under discrete wavelength band-pass filters and quantum yields of degradation, ɸ, were calculated for each filter (~10nm wavelength bands) across the DV region (270-380 nm). Values of ɸ closely matched literature studies validating the light exposure techniques and light intensity measurements used in this study. As accurate values of ɸ are difficult to obtain on plant surfaces due to light scattering and absorption then a novel 'pesticide action spectrum' (PAS) - a light weighted effective degradation rate - was developed to predict photolysis rates on salad- leaf surfaces with knowledge on the ambient light conditions. The PAS was tested for fenitrothion decay irradiated under a range of agricultural plastics commonly used as cladding for plastic-greenhouses. Light transmission is markedly reduced under these plastics, particularly in the DV actinic region, resulting in reductions in fenitrothion decay (k = 0.144 ± 0.021 hr-I for 'standard' plastic, compared to 0.258±0.028 hr-I in the absence of plastic film). Derived degradation rates for fenitrothion using the PAS, for the various spectral irradiances measured under the plastics, compared favourably to measured photolysis rates. The issue of pesticide degradation and fate in light-altered micro-environments like plastic- protected enclosures has implications for pesticide longevity on crop surfaces and is currently not accounted for in pesticide risk management regimes. The toxicity of OPs is commonly associated with inhibition of acetylcholinesterase (AChE) activity and hence disruptions of nerve signal transmission in a wide range of organisms from insects to mammals. Concentrations of OPs in natural waters, away from regions of direct pesticide use, are typically lower than threshold concentrations likely to disrupt AChE activity. Therefore, low-dose (10-12 to 10-8 M) toxicity assays were performed using fenitrothion, diazinon and 2-isopropyl-6-methyl-4-pyrimidinol (IMP) (a hydrolysis degradate of diazinon) on human breast cancer cells (MCF-7) to assess the genotoxicity of these chemicals. Exposure to OPs at low concentrations (10-12 to 10-8 M) revealed chromosomal damage akin to exposure to the known genotoxin, benzo[a]pyrene (B[a]P), as well as a fenitrothion-induced 2-fold increase in CYP-IAl and BCL-2 gene expressions, involved in enzyme formation and cell-death processes, respectively. Furthermore, the utilisation of ATR-FTIR spectroscopy revealed that each of the OP chemicals altered the biochemical 'signature' within exposed cells relative to control cells, notably in the lipid, protein, and DNA/RNA absorbance regions, providing strong evidence that exposure to OPs, notably for aquatic organisms, may be deleterious even at trace concentrations and that toxic effects may also arise due to exposure to OP transformation products (e.g. IMP) also identified in the various degradation experiments conducted in this thesis.
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Hill, Paul Spencer. "The environmental degradation of fibre reinforced pultruded polymer composites." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240930.
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French, Mark Andrew. "Environmental degradation and stress corrosion of hybrid fibre composites." Thesis, Kingston University, 1990. http://eprints.kingston.ac.uk/20537/.
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Boly, Mohamed. "Essays on foreign aid, political cycles and environmental degradation." Thesis, Université Clermont Auvergne (2017-2020), 2020. http://www.theses.fr/2020CLFAD014.
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Les effets observés du changement climatique sur les dernières décennies mettent en exergue le besoin et l’urgence de mobiliser suffisamment de ressources pour le ralentir et en atténuer les effets. Dans le cas des pays en développement, d’aucuns suggèrent que l’aide au développement aurait un rôle non des moindres à jouer dans cette lutte. Cependant, encore faudrait-il que les ambitions politiques des décideurs ne soient pas en compétition avec celles environnementales. Cette thèse examine les liens existants entre l’aide au développement, les cycles politiques et la dégradation de l’environnement, à travers trois chapitres empiriques. Le chapitre 2 étudie le lien entre l’aide et l’atténuation des émissions de CO2 dans 112 pays en développement. Il montre que l’effet de l’aide dépend du type de donneur, l’aide multilatérale étant plus susceptible de réduire la pollution que l’aide bilatérale pour laquelle il n’y a pas d’effet. Cependant, une aide bilatérale spécifiquement ciblée sur la protection de l’environnement contribue à réduire le niveau de pollution. Cet impact est toutefois non linéaire, un effet de réduction de la pollution n’étant observé que pour des montants importants d’aide bilatérale environnementale. Le chapitre 3 étudie les facteurs associés à l’allocation de l’aide bilatérale environnementale entre les pays bénéficiaires, sur la période 1990-2013. L’objectif est d’évaluer si l’aide bilatérale environnementale est motivée par des facteurs non environnementaux tels que les intérêts économiques et politiques des donneurs. Trois types de variables susceptibles d’influencer l’allocation de l’aide environnementale sont examinés : les besoins et les mérites environnementaux et non environnementaux des pays bénéficiaires, ainsi que les intérêts économiques et politiques des donneurs. Les variables relatives aux besoins et aux mérites environnementaux comprennent la vulnérabilité aux événements climatiques extrêmes et la rigueur de la politique environnementale. Les résultats des régressions montrent que si la vulnérabilité au changement climatique semble être un déterminant clé de l’aide environnementale, son allocation est peu ou pas liée aux efforts d’atténuation du changement climatique des bénéficiaires. Il trouve également peu d’évidence empirique sur une quelconque association entre les variables d’intérêt des donneurs et l’aide environnementale, en moyenne. Cependant, une analyse désagrégée révèle d’importantes hétérogénéités dans ces relations, et révèle ainsi que certains donneurs sont plus sensibles aux variables environnementales, tandis que d’autres semblent plutôt se concentrer sur leurs intérêts économiques et politiques. Le chapitre 4 explore l’impact des élections sur la politique environnementale et la dégradation de l’environnement, en utilisant un échantillon de 76 pays démocratiques de 1990 à 2014. Les estimations indiquent que les années électorales sont caractérisées par une augmentation des émissions de CO2, même si cet effet semble s’atténuer sur les années plus récentes. Il révèle également que cet effet n’est présent que dans les démocraties plus anciennes, où les électeurs sont plus avisés et où les dirigeants se livrent à des manipulations budgétaires via la composition des dépenses publiques plutôt que par leur niveau. Une plus grande liberté de la presse et des préférences environnementales élevées de la part des électeurs permettent de réduire l’ampleur de ce cycleThe observed effects of climate change over the last decades highlight the urgency of mobilizing enough resources to slow it down and mitigate its effects. In the case of developing countries, some suggest that development aid has an important role to play. However, the political ambitions of decision-makers should not be in competition with environmental ones. This thesis examines the existing links between foreign aid, political cycles and environmental degradation, through three empirical chapters. Chapter 2 studies the link between foreign aid and CO2 mitigation in 112 developing countries. It shows that the effect of aid depends on the donor, with multilateral aid more likely to reduce pollution than bilateral aid for which there is no effect. Nevertheless, a bilateral aid specifically targeted toward environment contributes to decrease the level of pollution. This later impact is non-linear, a pollution-reducing effect is only observed for important amounts of environmental bilateral aid. Chapter 3 studies the factors associated with environmental bilateral aid to recipient countries over the 1990-2013 period. The objective is to assess whether the environmental bilateral aid is motivated by non-environmental factors such as donors’ economic and political interests. Three kind of variables that might influence environmental aid allocation are examined: the environmental and non-environmental needs and merits of recipient countries, and the economic and political interests of donors. Environmental needs and merits variables include vulnerability to extreme climate events and the stringency of climate policy. The results show that while vulnerability to climate change seems to be a key determinant of environmental aid, its allocation is poorly linked to recipients’ climate mitigation policies. It finds weak evidence of association between donors’ interest variables and environmental aid on average. However, an heterogeneity analysis allows to go deeper into all the relations above, and unveils that some donors are more sensitive to environmental variables, while others rather seem focused on their economic and political interests. Chapter 4 explores how elections impact climate change policy and environmental degradation, using a sample of 76 democratic countries from 1990 to 2014. The findings indicate election years are characterized by an increase in CO2 emissions, even though the effect weakens over the recent years. It also reveals that this effect is present only in established democracies, where incumbents engage in fiscal manipulation through the composition of public spending rather than its level. Higher freedom of the press and high environmental preferences from citizens reduce the size of this “political pollution cycle”
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Vornovytskyy, Marina S. "Linkages between inequality and environmental degradation an interregional perspective /." Amherst, Mass. : University of Massachusetts Amherst, 2009. http://scholarworks.umass.edu/dissertations/AAI3349746/.
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Kanesund, Jan-erik. "Influence of deformation and environmental degradation of Inconel 792." Licentiate thesis, Linköpings universitet, Institutionen för ekonomisk och industriell utveckling, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-133824.
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Industrial gas turbines are often used as a mechanical drive for pumps and compressors or in power generation as an electric power supply. The gas turbine has for many years been a popular engine due to its flexibility with respect to different types of fuel and due to a design, that enables a high power-to-weight ratio. A simplified description of a gas turbine is that the engine consists of a cold and hot section. The turbo compressor section belongs to cold section and the combustion chamber together with the turbine section belongs to the hot section. In the hot section of a gas turbine, the condition is extremely severe because of an aggressive environment characterized by high temperatures, increased temperature gradients, high pressure and centrifugal forces resulting in large stresses on individual components together with an oxidizing and corroding atmosphere. Materials used in the high temperature section (hot gas path) of a modern gas turbine are different types of superalloys, as single crystal, directionally solidified or polycrystalline alloys, depending on temperature and load conditions. In the first turbine stage, temperature is very high due to exposure to the combustion gas. To handle the problem with creep, single crystal superalloys are often used in this section. In the second row of turbine blades, the temperature of the gas is lower and polycrystalline superalloys are typically used. IN-792 is a cast polycrystalline superalloy with high strength, good resistance to hot corrosion and a cheaper option than single crystals. In the hot section of gas turbine, IN-792 is a suitable material for components such as turbine blades and vans where a complex load condition, high temperature and severe environment prevails. Due to startup and shutdown of the gas turbine engine during service, the components in the hot section are exposed to cyclic load and temperature. This will generate mechanical and thermal fatigue damage in gas turbine components. Steady state temperature gradient arises by the cooling system acting at cold spots during service to introduce tensile stress, which indirectly gives rise to creep damage in the component. This work includes tree studies of deformation and damage mechanisms of superalloy IN-792. The first study is made on test bars exposed to thermomechanical fatigue in laboratory environment, the second and the third study is made on turbine blades used during service. In the second study, the machines are placed off-shore and exposed to marine environment. In the third study the machine is landbased and exposed to an industrial environment. In the second study, the deformation and damage mechanisms are compared between the turbine blades used during service and the test bars exposed to thermomechanical fatigue testing in the first study.
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Harrington, Tomas Seosamh. "Gas diffusion electrodes for environmental applications." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297872.
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Pius, Epie Ewanzimbi. "Significant outcomes of the West-Central African later Iron Age /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p3091957.
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Bhutia, Pop Tshering. "Environmental degradation : problems and prospects A Study in Kurseong Sub-Division of Darjeeling Himalaya." Thesis, University of North Bengal, 1999. http://hdl.handle.net/123456789/543.
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Goldblatt, David Steven. "Social theory and the environment : an analysis of the writings of Giddens, Gorz and Habermas on environmental degradation and environmental politics." Thesis, University of Cambridge, 1993. https://www.repository.cam.ac.uk/handle/1810/272672.
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MacPherson, Sarah Louise. "The social embeddedness of private sector environmental decisions in Hong Kong." Thesis, University of York, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288058.
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Zipper, Christian. "Microbial degradation and environmental fate of chiral phenoxyalkanoic acid herbicides /." [S.l.] : [s.n.], 1998. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=12543.
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Fernandez, Maria, and Sebastian José Caballero. "The grieving forest; the social-environmental degradation in Amazonian Rainforest." Thesis, Mälardalen University, School of Sustainable Development of Society and Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-739.
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The Amazonia is the biggest rainforest in the world, home also to probably the largest amount of different bio diversity species in our planet. Notwithstanding these incredible attributes, it is also one of the most threatened regions earth that extends to the whole planet. This thesis analyzes just a small segment of the interrelation of different human actors reacting to environmental problems. Theoretical frame works of different nature are used in this thesis in an effort to combine with synergy the strengths and potential benefits of political ecology, the stakeholder model, local institutionalisms, and the political and economical role of persons just to mention the most significant. This combination of these different scientific and empirical disciplines offers us a chance to apply the full potential for the analysis of the environmental problems related to human actions in the regional settings with the capability of gaining in depth knowledge that can be applied later in the design and implementation of potential alternatives seeking s the welfare of all human and biological stakeholders as our knowledge allows us currently. The thesis is structured on three study cases that cover a vast area of the Amazonia: the first case is located in Bolivia where we analyze the situation of Santa Maria de Maravilla, regarding the problems of land property and land use; the second case is located in Brazil in the Santarém region, where an important intensive production of soybean is affecting the environment as well as confronting the local communities; the third case is located in Ecuador analyzing the situation of the Block 15 region; an area deeply affected by the petroleum companies and the generic concepts of investment in extractive industries as a tool for regional and national development.
Local actors are of the highest importance despite the different nature of the case studies, in order find commonalities which might allow us to make hypothetical counteracting models to decrease the devastating of environmental degradation in the Amazonia; some of the external actors (like the NGOs) can play an influential role in order to improve the collaboration and trust with local members.
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Becker, Olga Maria Schild. "Recent settlement in Brazilian Amazonia : labour mobility and environmental degradation." Thesis, London School of Economics and Political Science (University of London), 2002. http://etheses.lse.ac.uk/2281/.
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The context of this thesis is Brazilian Amazonia and the subject is the discussion of labour force mobility and immobility as well as environmental degradation following current occupation process of this natural resource frontier. The overall aim is to identify the forms and mechanisms of the capitalist occupation process which has taken place in Amazonia in the 1960-1990 period. I consider the issues of increasing labour force mobility and environmental degradation as a question of changes in the relationship between people-nature. These changes in Brazilian Amazonia relate to an expansion of the territorial limits of capital and are a consequence of the occupation process encouraged by the Brazilian State. The central research question of this thesis is why and how does a regional development policy for Brazilian Amazonia, designed with the aim of promoting the occupation of the empty spaces of the frontier, lead to a progressive expulsion of the previous inhabitants of those areas. In the same way, why did government programmes not ensure a settling of the new colonists (landless migrants) on the land in these frontier areas where, by definition, we would suppose there are huge expanses of land available. The argument is that the Brazilian State, taking it for granted that the Northern frontier areas should be occupied, promoted a sort of occupation in which the frontier was to be expanded following a pattern of urbanised jungle, where the urban space was the support of this process. According to this strategy, the circulation (mobility) of the labour force was seen to be more relevant than the settlement of small landless producers. In this way, migration (as a mechanism in producing the labour force) played a crucial role in creating a regional labour market in frontier areas. Moreover, this thesis will discuss the Extractive Reserve model presented by the so-called traditional inhabitants as a proposal for rainforest productive conservation and counter-mobility of the labour force in Brazilian Amazonia. The present study analyses specific spaces in the Amazonia: the Pre- Amazonia Maranhense (Eastern Amazonia), considered an earlier frontier area from the 1960s, and the Acre River Valley (Western Amazonia), that represents a newer frontier area from the 1970s and 1980s.
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Sugiman. "Combined environmental and fatigue degradation of adhesively bonded metal structures." Thesis, University of Surrey, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.548357.
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The main objective of this research is to investigate the effect of moisture on the degradation of adhesively bonded aluminium joints under both static and fatigue loading. This has been achieved through a combination of experimentation and progressive damage finite element modelling (using a cohesive zone approach). Moisture uptake behaviour in the adhesive was studied to obtain the coefficient of moisture diffusion and of moisture expansion. The coefficient of thermal expansion was also measured to provide the data for the finite element modelling, which included residual stresses due to cooling from cure temperature and swelling of the adhesive layer. The moisture dependent properties of the adhesive were obtained from bulk adhesive tensile tests. The joints investigated included monolithic single lap joints loaded in tension and laminated doublers loaded in bending and tension. Various widths were used to get the full and partial saturation of the adhesive layer. Under both static and fatigue loading, the degradation increased with increasing moisture content and tended to level out when the moisture content approached the saturation level. Most of the failures were cohesive in the adhesive layer, showing that the degradation was due to adhesive, rather than interfacial degradation. Calibration of the cohesive properties was achieved by combining backface strain and load data measured in the monolithic single lap joint. These were then utilised to predict the residual strength of the doublers in bending. In fatigue, the calibrated cohesive zone properties were integrated with a strain-based fatigue damage model to simulate the fatigue response of the monolithic single lap joint and doubler loaded in bending both in the unaged and aged condition. The backface strain technique has been successfully used to monitor the fatigue damage evolution in the joints considered, to calibrate the parameters in the strain based fatigue model, and also to study the effect of adhesive fillet on the fatigue damage evolution in the doubler loaded in bending. Doublers loaded in tension exhibited an entirely different failure mechanism including rupture of both the adhesive and aluminium layer. The effect of moisture on the 11 degradation of this joint was not significant. The butts between aluminium sheets that inevitably exist in laminates were shown to affect the strength of the joint. For these joints, the progressive damage modelling used a cohesive zone approach for the adhesive layer and the butt, and continuum damage for the aluminium layer. In fatigue, the cohesive zone and the continuum damage were integrated with the strain-based fatigue damage model to predict the response. The predicted response under both static and fatigue loading was found to be in good agreement with the experimental data. Finally, experimental and numerical studies have been undertaken on hybrid fibre-metal (aluminium-Glare) laminate (FML) doubler joints to investigate their response under static and fatigue tension loading. The specimens had fibres either parallel to the loading direction (spanwise) or perpendicular to the loading direction (chordwise). Again, the effect of the butt position was investigated. The spanwise specimen was found to have the highest strength followed by chordwise specimens without butts and finally chordwise specimens with butts. The most critical position for a butt was found to be adjacent to the doubler end. Without butts, the static strength for spanwise and chordwise specimens was controlled by the failure in the Glare layer whilst the fatigue failure was precipitated by failure in the aluminium sheet. Where butts are present, they significantly influence the joint response. A progressive damage numerical analysis was undertaken and was found to be in good agreement with the experiment data in terms of both the strength and the failure mechanisms.
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Jumbo, Furopanyekirim Samuel. "Modelling residual stresses and environmental degradation in adhesively bonded joints." Thesis, Loughborough University, 2007. https://dspace.lboro.ac.uk/2134/17955.
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The aim of this research was to develop predictive models for residual stresses and environmental degradation in adhesively bonded joints exposed to hot/wet environments. Different single lap joint configurations and a hybrid double lap joint with dissimilar adherends (CFRP/AIIFM73 double lap joint), were exposed to different ageing environments in order to determine the durability of the joints and the effects of ageing on the failure load. Thermal residual stresses in bonded joints were investigated with analytical solutions and finite element modelling, first with a bimaterial curved beam to validate the modelling process and determine the most suitable method for calculating thermal stresses in bonded joints. It was found that none of the analytical solutions and 2D geometric approximations was fully able to describe the 3D stress state in the strip. The incorporation of geometric and material non-linearity into the models was necessary to obtain accurate results. The validated methods were then used predict the thermal residual stresses in bonded lap joints. The thermal stresses were found to be highest in joints with dissimilar adherends. Moisture uptake in bonded joints was investigated using Fickian diffusion modelling. Gravimetric experiments were used to determine the Fickian diffusion parameters for the bulk adhesive and composite adherends. Transient diffusion modelling was used to predict the uptake in bonded joints. It was seen that moisture diffusion is a fully three dimensional process, and the effects of moisture absorption can only be adequately studied using 3D FEA. The effects of swelling from moisture absorption in bonded joints were investigated using coupled stress-diffusion FEA models. Coupled stress-diffusion 3D FEA was used to predict the transient and residual hygroscopic stresses that develop in bonded lap joints as a function of exposure time in accelerated ageing environments, taking into account the effects of moisture on the expansion and mechanical properties of the adhesive and CFRP substrate. It was seen that moisture absorption induces significant stresses in the joints and markedly different behaviour was seen in the cases of absorbent and non-absorbent adherends. Hygro-thermo-mechanical stresses arising from the exposure of single and double lap joints with thermal residual stresses to hot/wet environments were investigated. In the single lap joints, a reduction in the stresses present in the adhesive was predicted, owing to swelling of the adhesive from moisture absorption. In the double lap joint with dissimilar adherends, exposure to hot/wet environments initially reduced the stresses in the joint when dry, followed by an increase in the magnitude of some stress components and reductions in others with increasing levels of moisture absorption. This led to a higher equivalent stress state in the adhesive than when dry. Thermal residual and mechanical strains predictions were validated with internal strains measured by neutron diffraction and surface strains measured by moire interferometry. Comparisons of predicted and measured thermal residual strains showed low levels of strain in joints with similar adherends. The magnitude of strains in the CFRP/AI double lap joint was significant, with the same spatial distribution and magnitude in both measured and predicted strains. The comparison of mechanical strains predicted by FEA and measured strains by moire interferometry showed good agreement. High magnification moire interferometry also confirmed the location of strain concentrations predicted by FEA. A path independent cohesive zone model (CZM) and a coupled continuum damage model were used to predict and characterise damage and failure initiation in bonded joints. Progressive failure prediction was calibrated in the cohesive zone model using the moisture dependent cohesive fracture energy of FM73. There was a reasonably good agreement with the experimental failure loads. This implementation of the cohesive zone model is limited by the ability of the interface elements used, thereby creating mesh dependency. The Gurson-Tvergaard-Needleman (GTN) coupled damage model was used to predict the effects of residual stresses on failure loads. However, this method is difficult to implement, given the numerous parameters required. The failure loads predicted by the GTN model were comparable with the experimental data when the joints were dry or wet. The damage models were capable of predicting the sudden crack growth and propagation seen experimentally.
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Law, Cheuk Fung Japhet. "Catalytic advanced oxidation processes for degradation of environmental emerging contaminants." HKBU Institutional Repository, 2019. https://repository.hkbu.edu.hk/etd_oa/610.
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In recent years, the increasing release of trace organic chemicals to the aquatic environment have been problematic to both the ecosystem and the human society. These trace organic chemicals, regarded as emerging contaminants, include different categories of chemicals, which are either deemed to be safe for human consumption or they are naturally occurring compounds. As a newly recognized class of emerging contaminant, artificial sweeteners are proven to be one of the most ubiquitous classes of emerging contaminants in environmental waters. Its transformation to different suite of TPs during water treatment processes generated more toxic influence than the parent compound is problematic. The realization of the widespread of emerging contaminants, together with their ambiguous fate and impact to the environment have led to the development of advanced oxidation processes that can effectively attenuate this wide range of contaminants. In this work, several catalytic advanced oxidation processes were studied. On one hand, it aimed to evaluate their effectiveness on the removal of the artificial sweetener - acesulfame; and on the other hand, to shed lights on the future development of catalytic advanced oxidation processes. In the first part of this thesis, the photo-Fenton treatment was evaluated on its potential to effectively remove acesulfame together with the produced transformation products, and the post-treatment toxicity screening. The photo-Fenton treatment was found to be effective in removing both the parent compound and the transformation products, without leading to an increase in toxicity, which is largely related to the effective removal of the transformation products. In attempt to reduce the reliance on UV irradiation, newly synthesized carbon and nitrogen co-doped TiO2-based photocatalyst was applied to capture the simulated sunlight for the degradation of acesulfame. The heterogenous photocatalytic treatment was found to involve several different oxidative reactive species for both degradation and transformation by using several scavengers to alter the degradation profile. Unexpected transformation product was also formed upon treatment in actual water matrix, suggesting the impact of water constituents to the transformation of emerging contaminants. Toxicity results indicated the inability to achieve detoxification, suggesting that a more effective degradation process was needed. To accelerate the degradation process, and enhance the performance at neutral pH, the use of redox mediators for Fenton/Fenton-like system was evaluated. Developed novel Fenton-like system involving copper(II) as transition metal ion, persulfate as oxidant and mercaptosuccinic acid as redox mediator led to effective removal of different contaminants. Elucidation of the proposed oxidation mechanism suggested the role of each components of the system, and the generation of different reactive species for degradation as indicated by the different acesulfame transformation profile obtained. The implementation of redox mediators to Fenton/Fenton-like system was beneficial and an effective approach. In short, this work presents several kinds of catalytic advanced oxidation process and shed lights on improving the degradation performance with directions for the future development of better and more effective water treatment processes.
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Stagl, Sigrid. "Delinking economic growth from environmental degradation? A literature survey on the Environmental Kuznets Curve hypothesis." Inst. für Volkswirtschaftstheorie und -politik, WU Vienna University of Economics and Business, 1999. http://epub.wu.ac.at/1490/1/document.pdf.
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The effect of economic growth on environmental quality is much under dispute. A number of empirical studies have made the claim that there exists in some income ranges a positive relation between per capita income and some measure of environmental quality. According to this inverted U-shaped pattern of different pollutants relative to per capita incomes in different countries which is also called the "Environmental Kuznets Curve" (EKC), environmental pressure increases up to a point as income goes up; after the turning point environmental quality improves as income keeps rising. Possible explanations for this pattern are seen in the progression of economic development, from clean agrarian economies to polluting industrial economies to clean service economies. This trend is enhanced through the transfer of cleaner technology from high-income countries to low-income countries and the tendency of people with higher income having a higher preference for environmental quality. Since this relationship is so fundamental to questions of economic development and sustainability it has provoked a vast load of research over the last seven years supporting but also heavily criticizing the results and conclusions. This paper gives an overview of the literature published on this topic to date and the conceptual, methodological and fundamental critique put forward. (author's abstract)Series: Working Papers Series "Growth and Employment in Europe: Sustainability and Competitiveness"
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Sporring, Jonsson Elin. "Environmental Security : A conceptual investigating study." Thesis, Jönköping University, JIBS, Political Science, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-8106.
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The purpose of this thesis is to explore the concept of environmental security. A concept that have made way on to the international arena since the end of the Cold War, and have become of more importance since the 1990’s. The discussion regarding man-made environmental change and its possible impacts on the world is very topical; especially with the Nobel Peace Prize winners in 2007 the Intergovernmental panel on climate change (IPCC) and Al Gore.The concept of environmental security is examined through a conceptual investigating study. The reason for this type of study is due to the complexity of the concept and a hope to find a ‘best’ definition to it. A conceptual investigating study is said to help create order in an existing discussion of a social problem, hence the reason for it in this thesis. The outcome of this thesis is that it is near impossible to find a ‘best’ or one definition to the concept of environmental security and that another method to deal with the concept might have presented another result.
Syftet med denna uppsats är att undersöka konceptet environmental security. Detta koncept har gjort sin väg till ett internationellt erkännande sedan Kalla kriget, och har sedan 1990-talet blivit allt mer aktuellt. Diskussionen gällande människans inverkan på klimatförändringarna och klimathotet är ständigt aktuellt, i synnerhet med tanke på vinnarna av Nobels Freds Pris 2007, med Al Gore i spetsen.Konceptet environmental security är i denna uppsats undersökt genom en begreppsutredande studie. Anledningen till denna typ av studie är att konceptet är såpass komplext men även baserat på hoppet av att hitta en ’bästa’ möjliga definition. Begreppsutredande studier sägs kunna skapa ordning i en existerande diskussion vilket kan ses som den främsta anledningen valet av den i denna uppsats.Resultatet av studien och denna uppsats är att det är i stort sett omöjligt att etablera en bästa definition av begreppet environmental security, samt att en annan metod förmodligen hade presenterat ett annat resultat.
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Evanshen, Brian G., C. Knight, A. Zaslow, Phillip R. Scheuerman, and G. R. Lanza. "In Situ Degradation of M-Cresol in Creosote Contaminated Soil." Digital Commons @ East Tennessee State University, 1992. https://dc.etsu.edu/etsu-works/2892.
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Nalli, Sandro. "Biological degradation of plasticizers and their metabolites." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85630.
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Plasticizers are widely used as additives for the production of PVC and other types of plastics. They have been observed to leach out of the solid matrix over the course of the lifetime of the finished product. These compounds have now been observed across the globe and in different environments. The main focus of this work is the study of the interactions of industrial plasticizers with soil microorganisms including bacteria, yeast and fungi.This research is concerned with the microbial degradation of plasticizers such as di-2-ethylhexyl phthalate (DEHP) and di-2-ethylhexyl adipate (DEHA). In particular, the study has focused on the stable metabolites produced during biodegradation, including 2-ethylhexanol and 2-ethylhexanoic acid. The first step was to show that these toxic metabolites were found in significant concentrations in the environment. In addition, a series of experiments with a variety of organisms showed how wide spread the ability to produce these metabolites was. Most organisms tested were capable of interacting with the plasticizers and many of these produced the metabolites.
It was apparent that these metabolites could have appreciable stability and an in-depth study with one species of bacteria, R.rhodochrous , showed that the entire initial 2-ethylhexanol component incorporated in the original plasticizers could be accounted for. Some of this was volatile and found in the exit gas of the reactor. This included all of the 2-ethylhexanol and some of the 2-ethylhexanol. These compounds may contribute to the impairment of the quality of indoor air. An overall mass balance showed that while the bacterium could eventually oxidize the 2-ethylhexanol released by hydrolysis to 2-ethylhexanoic acid, it could not degrade this acid. Thus, a summation of the quantities of each of the various metabolites generated equaled the original amount of 2-ethylhexanol in the plasticizer.
A mathematical model was then constructed to include all of the above features of the interaction of R.rhodochrous with the plasticizers DEHA and DEHP. This model included terms for the biological interactions and enzyme kinetics as well as the toxicity and inhibition of bacterial growth by the plasticizers and their metabolites. The increased understanding of the interaction of microbes with plasticizers will lead to a better understanding of the environmental impact of these compounds and their metabolites. The results of this study also demonstrate that when assessing the environmental impact of a compound, it is essential that not only should the impact of the parent compound be considered, but it is essential that the assessment process must also account for impacts associated with degradation products.
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Termtanun, Mutsee. "Photocatalytic degradation of pesticides using TiO2 nanoparticles." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13827/.
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The problem of water pollution has been an environmental concern for many years. Numerous researchers are looking for an effective method to solve this issue. Heterogeneous photocatalysis, using a semiconductor as a catalyst, is a promising method for the destruction of water polluting pesticides. This method has been called the Advanced Oxidation Process (AOP) which is one of the techniques for water treatment. Titanium dioxide (TiO2) is the most widely accepted photocatalyst because it is non-toxic, stable to photocorrosion, low cost and can potentially work using sunlight rather than artificial sources of light. When titanium dioxide is illuminated by UV radiation, the absorption of photons of energy is then equal to or greater than its band gap width. This artefact leads to the formation of conduction-band electrons and valence-band holes on the surface of TiO2, which yield hydroxyl radicals, the primary oxidising species needed for the photocatalytic degradation of pollutants. Supercritical water hydrothermal synthesis (ScWHS) is one of novel approaches for nanoparticle manufacture which involves the mixing of an aqueous metal salt stream with a supercritical water stream to produce nano-sized metal oxide particles. The engineering design for the mixing of these two fluids is critical and a novel nozzle reactor has been developed at the University of Nottingham that can produce high quality particles with an excellent control over particle size and particle size distribution. By application of this technique, titanium dioxide (TiO2), in nanoparticle form, was produced and used for the photocatalytic treatment of wastewater. In this thesis, the photocatalytic degradation of the three pesticides - isoproturon, simazine and propazine - was measured using 3 different types of reactors: thin film fixed bed reactor (TFFBR), a stirred reactor, and a fluidised bed photoreactor. Various conditions were used: for example without UVC and UVA illumination, with commercial TiO2, with the synthesised TiO2, without any photocatalyst, low concentration, high concentration, and at different TiO2 concentrations. The optimum TiO2 concentration for the treatment of the three chosen pesticides was equal to 5 g litre-1. The efficiency in decreasing the pesticides concentration of the synthesised TiO2 (from ScWHS technique) with all three types of reactors was lower than that of the commercial titanium dioxide (P-25 TiO2). The fluidised bed reactor appeared to give the highest performance amongst three reactors.
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King, Sarah M. "Enhancement in Degradation of Environmental Pollutants: Fenton Degradation of 2,4,6-Trinitrotoluene and Photodegradation of Deepwater Horizon Crude Oil." ScholarWorks@UNO, 2012. http://scholarworks.uno.edu/td/1451.
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Pollution poses serious threats to both the environmental and the organisms that depend on their environment for survival. Due to the toxicity of most contaminants, there is a dire need for remediation of polluted sites. Remediation studies were conducted on two high priority pollutants: 2,4,6-trinitrotoluene (TNT) and crude oil.
TNT was the most common explosive used in the 20th century. Continuous contamination has resulted in an urgent need for remediation. Fenton reagent provides an advanced oxidation process that is capable of remediating recalcitrant explosives, such as TNT. One drawback of Fenton chemistry is that the reaction requires acidic pH to prevent precipitation of iron. Our studies have investigated Fenton degradation of TNT at near neutral pH with several modifiers present: β-cyclodextrin, carboxymethyl-β-cyclodextrin, alcohols, and polyethylene glycol (PEG, MW 200, 400, or 600 g/mol). Fenton degradation was also carried out on other nitroaromatics to better understand the reaction mechanism with PEG 400. Further mechanistic studies investigated the production of nitrate and ammonium with and without PEG 400.
The Deepwater Horizon oil spill devastated the Gulf of Mexico and the surrounding wetlands. There are several mechanisms for degradation of oil released into aquatic environments. Bioremediation is one of the most important remediation methods; however degradation becomes stagnant in low nutrient waters. Furthermore, larger molecular weight alkanes and polycyclic aromatic hydrocarbons (PAHs) are not readily available for biodegradation. Transformation of these molecules often requires initial photodegradation. We have investigated the photochemical transformation of oil films with and without photocatalysts present. To better understand the photochemical transformations that occur to the Deepwater Horizon oil, we have conducted additional studies with dispersants present.
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Dikirr, Patrick Maison. "Africa's environmental crisis unmapped terrain, existing challenges, and possible solutions /." Diss., Online access via UMI:, 2005. http://wwwlib.umi.com/dissertations/fullcit/3164703.
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Akahalu, U. A. "Interrogating frustration-aggression from environmental degradation in the Niger Delta conflict." Thesis, Nottingham Trent University, 2014. http://irep.ntu.ac.uk/id/eprint/28027/.
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This study interrogates what motivates the major beneficiaries of the Bayelsa State (Niger Delta) environment – the multinational oil corporations (MNOCs) and the Nigerian government (NG) to degrade that environment – their benefactor. The special interest of this thesis lies in understanding why the degradation continued even with the knowledge that their actions threaten the existence of the indigenous oil-bearing host communities (OBHCs) of Bayelsa State (Niger Delta). Irrespective of the fact that the Niger Delta conflict has been a favourite subject for scholars over the years, this particular aspect of the conflict has not been found amongst the literature consulted for this study. To fill this gap, this thesis interrogates this phenomenon. To address this phenomenon, this study reviewed relevant literature to understand the dynamics of environmental degradation through the application of instrumental aggression by the major beneficiaries, and the reactive aggression employed by the OBHCs, as a response to the former. Employing ethnographic tools for data collection involving in-depth interviews, participant observation and focus group discussions, the frustration-aggression theory deployed here emphasises that an individual or a group that has experienced severe deprivations, marginalisation or obstructions in reaching its goal, may transform from a frustrated group to an aggressive one. With the use of this theoretical framework and the proposed theoretical model: Self-Inflicted-Frustration-Aggression-Theory (SIFAT), this study found that the Niger Delta’s connection with the defunct Republic of Biafra was responsible for their neglect, marginalization, violation and the despoliation of its environment. The thesis found that the obstructions to OBHCs’ constitutional means of resolving the problem was the major factor transforming frustrations into aggression and violent conflict in Bayelsa state (Niger Delta).
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England, Joseph. "The Colonial Legacy of Environmental Degradation in Nigeria's Niger River Delta." Master's thesis, University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5198.
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Nigeria's petroleum industry is the lynchpin of its economy. While oil has been the source of immense wealth for the nation, that wealth has come at a cost. Nigeria's main oil-producing region of the Niger River Delta has experienced tremendous environmental degradation as a result of decades of oil exploration and production. Although there have been numerous historical works on Nigeria's oil industry, there have been no in-depth analyses of the historical roots of environmental degradation over the full range of time from the colonial period to the present. This thesis contends that the environmental degradation of Nigeria's oil producing region of the Niger Delta is the direct result of the persistent non-implementation of regulatory policies by post-independence Nigerian governments working in collusion with oil multinationals. Additionally, the environmental neglect of Nigeria's primary oil-producing region is directly traceable back to the time of colonial rule. Vital to this argument is the view that the British colonial state created the economic institutions which promoted Nigerian economic dependency after independence was achieved in 1960. The weakness of Nigeria's post-colonial dependent system is exposed presently through the continued neglect of regulatory policies by successive post-colonial Nigerian governments.M.A.
Masters
History
Arts and Humanities
History; Public History
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Forsyth, Timothy Julian. "Environmental degradation and tourism in a Yao village of northern Thailand." Thesis, SOAS, University of London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285700.
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