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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
321

Estudos sobre a adsorção do corante reativo preto 5 de solução aquosa  usando zeólita de  cinzas de carvão / Studies on the adsorption of reactive black 5 dye of aqueous solution using zeolite of the coal ashes

Ferreira, Patricia Cunico 27 April 2011 (has links)
Nesta dissertação foi estudada a zeólita sintetizada a partir de cinzas leves de carvão como um potencial adsorvente para a remoção de corante reativo preto 5 (RP5). Ensaios cinéticos e de equilíbrio foram realizados visando obter-se as melhores condições para a adsorção deste corante, e verificou-se a influência dos seguintes parâmetros: efeito do tempo de contato, concentração inicial do corante, dose do adsorvente, pH da solução aquosa, adição dos sais NaCl e Na2SO4 e temperatura. O tempo de equilíbrio foi alcançado após 420 min. Os dados de adsorção foram ajustados melhor ao modelo cinético de pseudo-segunda-ordem. Para o sistema corante/adsorvente foi aplicado o modelo de isoterma de adsorção de Langmuir, apresentando capacidade de adsorção máxima de 0,685 mg g-1. Os dados experimentais mostraram uma alta porcentagem de remoção de 47,7 a 88,1% de RP5 sobre a zeólita. A alta porcentagem indicou que o material zeolítico apresenta potencial para ser usado como adsorvente na remoção de corantes azo reativo de indústrias têxteis. Os parâmetros termodinâmicos foram avaliados e demonstraram que o processo de adsorção do RP5 sobre a zeólita é espontâneo e exotérmico. Os experimentos adicionando os sais foram realizados para uma melhor simulação das condições reais do efluente. Os resultados mostraram que o equilíbrio de adsorção do RP5 sobre a zeólita na presença de sais foram alcançados em um tempo menor e que quanto maior a concentração dos sais na solução, maior a capacidade de adsorção. O resultado obtido na avaliação da toxicidade pelo microcrustáceo Daphnia similis, o tratamento de adsorção com zeólita se mostrou extremamente favorável5 reduzindo a carga tóxica e cor do efluente aquoso. / In this dissertation was studied the zeolite synthesized from coal fly ash as a potential adsorbent for the removal of reactive Black 5 dye (RP5). Equilibrium and kinetic experiments were conducted to obtain the best conditions for the adsorption of this dye, and observed the influence of the following parameters: effect of contact time, initial dye concentration, adsorbent dose, pH of the aqueous solution, addition of NaCl and Na2SO4 and temperature. The equilibrium time was reached after 420 min. The adsorption data were fitted better by a pseudo-second-order. For the dye / adsorbent system was applied to the model of Langmuir adsorption isotherm, with maximum adsorption capacity of 0.685 mg g-1. The experimental data showed a high percentage of removal from 47.7 to 88.1% of RP5 on the zeolite. The high percentage indicates that the zeolitic material has a potential to be used as adsorbent in the removal of azo dye reactive textile industries. The thermodynamic parameters were evaluated and showed that the adsorption process of RP5 on the zeolite is spontaneous and exothermic. The experiments were performed by adding salts to better simulate actual conditions in the effluent. The results showed that the adsorption equilibrium of reactive black 5 on the zeolite in the presence of salts were achieved in a shorter time and that the higher the concentration of salts in solution, the higher the adsorption capacity. The result obtained in the evaluation of toxicity by microcrustacean Daphnia similis treatment with zeolit adsorption was extremely favorable, reducing the toxic load of waste water and color.
322

Avaliação ecotoxicológica dos percolados das colunas de cinza de carvão e de solos com cinza de carvão utilizando Lactuca sativa e Daphnia similis como organismos teste / Ecotoxicological evaluation of leachates from columns of coal fly ash and soil with coal fly ash using Lactuca sativa and Daphnia similis as test organism

Castro, Flávia Junqueira de 22 February 2013 (has links)
As cinzas resultantes da queima de carvão por usinas termelétricas tem sido uma fonte de contaminação constante devido a seu descarte sobre o solo de forma inadequada. Os elementos tóxicos presentes na cinza de carvão quando lixiviados da cinza para o solo podem ficar biodisponíveis e serem absorvidos por plantas, consumidos por animais ou ainda transportados para diversas matrizes ambientais, tais como, águas subterrâneas e águas superficiais. Ensaio de germinação e desenvolvimento das radículas de Lactuca sativa e ensaio de toxicidade aguda com Daphnia similis foram realizados para avaliar a toxicidade dos percolados de colunas de cinza de carvão e de solo com cinza de carvão. De acordo com os valores obtidos por meio dos ensaios de germinação e desenvolvimento das radículas de L. sativa foram observados efeitos tóxicos à germinação das sementes de L. sativa nos percolados da coluna de cinza de carvão. Os valores médios de CI50(120h) destes percolados variaram de 27,6 a 90,6% e os valores do índice de germinação (IG) variaram de 6,7 a 40,8. Nos ensaios de toxicidade aguda com os organismos teste D. similis também foram observados efeitos tóxicos à mobilidade e/ou sobrevivência dos organismos expostos aos percolados da coluna de cinza de carvão. Os valores obtidos para CE50(48h) nestes percolados variaram de 25,6 a 84,1%. Os percolados das colunas de solo com cinza de carvão não apresentaram toxicidade tanto à L. sativa como à D. similis. Os resultados obtidos por meio destes ensaios ecotoxicológicos para os percolados das colunas de cinza de carvão e de solo com cinza de carvão indicam que o solo das colunas retiveram as substâncias tóxicas lixiviadas da cinza de carvão, ou seja, os solos utilizados nestas colunas atuaram como filtros. / The coal fly ash of power plants has been a constant source of contamination due to the improperly disposed on the soil. The toxic elements leached from coal fly ash when in contact with soil could become bioavailable and be absorbed by plants, consumed by animals or transported to different environmental matrices, such as groundwater and surface water. Seed germination and root elongation tests with Lactuca sativa and acute toxicity tests with Daphnia similis were done to evaluate the toxicity of the leachate from coal fly ash and soil with coal fly ash columns. According to the values obtained for the seed germination and root elongation tests were observed toxic effects to seed germination of L. sativa for the leachates from coal fly ash column. The mean values of IC50(120h) for these leachates ranged from 27.6 to 90.6% and the germination index values (IG) ranged from 6.7 to 40.8. In the acute toxicity tests with test organisms D. similis were also observed toxic effects to mobility and/or survival of organisms exposed to leachates of the coal fly ash column. The values obtained for EC50(48h) for these leachates range from 25.6 to 84.1%. The leachates of soil with coal fly ash columns not presented toxicity to both test organisms, L. sativa and D. similis. The data obtained by these ecotoxicological tests to the leachates of soil coal fly ash and soil with coal fly ash columns indicate that the soil of the columns have retained the toxic substances leached from the coal fly ash, thus the soils used in these columns have acted as filters.
323

Chemical interactions and mobility of species infly ash-brine co-disposal systems

Fatoba, Ojo Olanrewaju January 2010 (has links)
<p>The primary aim of these coal fired industries for co-disposing fly ash and brine was to use the fly ash as a sustainable salt sink. It is therefore important to study the interaction chemistry of the fly ash-brine systems to fully understand the leaching and mobility of the contaminant species, and to determine the possibility of capturing the salts from the brine solution when fly ash and brine are co-disposed. In order to achieve the aims and objectives of this study, several leaching procedures such as batch reaction tests, long-term fly ash-brine interaction tests, acid neutralization capacity (ANC) tests, up-flow percolation tests and sequential extraction tests were employed. The geochemical modeling software was applied to predict the formation of secondary mineral phases controlling the release of species in the fly ash-brine systems. Several analytical techniques such as x-ray diffraction (XRD), x-ray fluorescence (XRF), scanning electron microscopy-energy dispersion spectroscopy (SEM-EDS), inductively coupled plasma-mass spectroscopy (ICP-MS) and ion chromatography (IC) were applied to characterize the fresh fly ashes, solid residues recovered from the fly ash-brine interaction tests, the brine sample used in this study and the leachate samples in order to determine the chemical and mineralogical compositions and speciation of the waste materials.</p>
324

Synchrotron X-ray absorption spectroscopy and thermal analysis study of particle-reinforced aluminium alloy composites

Uju, Williams Alozie 20 April 2009
There is a great need in the transportation industry for high strength, high stiffness and lightweight materials with excellent dimensional stability. The use of these materials reduces fuel consumption and greenhouse gas emission as well as malfunctioning of components when subjected to fluctuating temperatures. Metal matrix composites (MMCs) are designed to meet these needs of transportation and other industries. However, their use is limited by lack of information on their thermal behaviour. In addition, reactions that occur in MMCs alter their microstructure and properties. These reactions have been widely investigated using X-ray Diffractometry (XRD) and electron microscopy (EM). However, these techniques cannot provide information such as charge transfer and local elemental structures in materials. Synchrotron X-ray Absorption Spectroscopy (XAS) could be used to identify reaction products in MMCs as well as provide information which XRD and EM cannot provide.<p> The thermal behaviour of Al-Mg alloy A535 containing fly ash particles as well as charge transfer and reactivity in particulate aluminium alloy metal matrix composites (MMCs) were investigated in this work. The materials studied were (i) Al-Cu-Mg alloy AA2618 and its composites reinforced with 10 and 15 vol.% alumina (Al2O3) particles and (ii) Al-Mg alloy A535 and its composites reinforced with a mixture of 5 wt.% fly ash and 5 wt.% silicon carbide, 10 wt.% and 15 wt.% fly ash. The investigative techniques used included Differential Scanning Calorimetry (DSC), Thermomechanical Analysis (TMA), Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and synchrotron X-ray Absorption Spectroscopy (XAS).<p> The results obtained showed that the coefficient of thermal expansion (CTE) of A535 decreased with the addition of fly ash and silicon carbide. Also, the addition of these particles improved the dimensional stability of the alloy in that the residual strain, åp, cycling strain, åc, and CTE decreased. The results obtained from XAS measurements showed evidence of charge redistribution in the aluminium in AA2618 with the addition of alumina particles. The results obtained from XAS measurements showed evidence of charge redistribution in the aluminium in AA2618 with the addition of alumina particles. The addition of alumina particles into AA2618 increased the p-orbital population and also changed the surface chemistry of the matrix. It was also demonstrated that the XAS technique can be used to determine the presence of various oxides in industrial fly ash and spinel (MgAl2O4) in alumina and fly ash particles extracted from the MMCs.
325

Synchrotron X-ray absorption spectroscopy and thermal analysis study of particle-reinforced aluminium alloy composites

Uju, Williams Alozie 20 April 2009 (has links)
There is a great need in the transportation industry for high strength, high stiffness and lightweight materials with excellent dimensional stability. The use of these materials reduces fuel consumption and greenhouse gas emission as well as malfunctioning of components when subjected to fluctuating temperatures. Metal matrix composites (MMCs) are designed to meet these needs of transportation and other industries. However, their use is limited by lack of information on their thermal behaviour. In addition, reactions that occur in MMCs alter their microstructure and properties. These reactions have been widely investigated using X-ray Diffractometry (XRD) and electron microscopy (EM). However, these techniques cannot provide information such as charge transfer and local elemental structures in materials. Synchrotron X-ray Absorption Spectroscopy (XAS) could be used to identify reaction products in MMCs as well as provide information which XRD and EM cannot provide.<p> The thermal behaviour of Al-Mg alloy A535 containing fly ash particles as well as charge transfer and reactivity in particulate aluminium alloy metal matrix composites (MMCs) were investigated in this work. The materials studied were (i) Al-Cu-Mg alloy AA2618 and its composites reinforced with 10 and 15 vol.% alumina (Al2O3) particles and (ii) Al-Mg alloy A535 and its composites reinforced with a mixture of 5 wt.% fly ash and 5 wt.% silicon carbide, 10 wt.% and 15 wt.% fly ash. The investigative techniques used included Differential Scanning Calorimetry (DSC), Thermomechanical Analysis (TMA), Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and synchrotron X-ray Absorption Spectroscopy (XAS).<p> The results obtained showed that the coefficient of thermal expansion (CTE) of A535 decreased with the addition of fly ash and silicon carbide. Also, the addition of these particles improved the dimensional stability of the alloy in that the residual strain, åp, cycling strain, åc, and CTE decreased. The results obtained from XAS measurements showed evidence of charge redistribution in the aluminium in AA2618 with the addition of alumina particles. The results obtained from XAS measurements showed evidence of charge redistribution in the aluminium in AA2618 with the addition of alumina particles. The addition of alumina particles into AA2618 increased the p-orbital population and also changed the surface chemistry of the matrix. It was also demonstrated that the XAS technique can be used to determine the presence of various oxides in industrial fly ash and spinel (MgAl2O4) in alumina and fly ash particles extracted from the MMCs.
326

Effect Of Cyclic Swell-shrink On Swell Percentage Of An Expansive Clay Stabilized By Class C Fly Ash

As, Mehmet 01 February 2012 (has links) (PDF)
Expansive soils are a worldwide problem especially in the regions where climate is arid or semi arid. These soils swell when they are exposed to water and shrink when they dry. Cyclic swelling and shrinkage of clays and associated movements of foundations may result in cracking of structures. Several methods are used to decrease or prevent the swelling potential of such soils like prewetting, surcharge loading, chemical stabilization etc. Among these, one of the most widely used method is using chemical admixtures (chemical stabilization). Cyclic wetting and drying affects the swell &ndash / shrink behaviour of expansive soils. In this research, the effect of cyclic swell &ndash / shrink on swell percentage of a chemically stabilized expansive soil is investigated. Class C Fly Ash is used as an additive for stabilization of an expansive soil that is prepared in the laboratory environment by mixing kaolinite and bentonite. Fly ash was added to expansive soil with a predetermined percentage changing between 0 to 20 percent. Hydrated lime with percentages changing between 0 to 5 percent and sand with 5 percent were also used instead of fly ash for comparison. Firstly, consistency limits, grain size distributions and swell percentages of mixtures were determined. Then to see the effect of cyclic swell &ndash / shrink on the swelling behavior of the mixtures, swell &ndash / shrink cycles applied to samples and swell percentages were determined. Swell percentage decreased as the proportion of the fly ash increased. Cyclic swell-shrink affected the swell percentage of fly ash stabilized samples positively.
327

Melting Treatment of Municipal Incinerator Fly Ashes by an Electric Arc Furnace in a Steel Mill

Chuang, Tsun-Nan 08 July 2003 (has links)
In this work, feasibility of utilizing municipal incinerator fly ash (MIFA) of different sources as a substitute of raw materials for steel-making in a mini-mill was studied. Also studied included the efficacy of this mode of melting treatment and recycling. Under the condition of adding 1 wt% MIFA to scrap iron/scrap steel for partial replacement of lime, the L9 orthogonal arrays of Taguchi methods were utilized to investigate the effects of MIFA melting treatment of different sources by an electric arc furnace (EAF). Four experimental factors (i.e., scrap iron mass, lime mass, coke mass, and MIFA mass) were selected to study their effects on Pb leaching of EAF dust and slag. Test results for MIFA obtained from Plants K1, K2, and K3 show that EAF dust remains hazardous as it is originally a listed waste. On the other hand, slag so generated remains nonhazardous based on the TCLP results. The experimental results of EAF dust and slag were further subjected to the analysis of variance (ANOVA) and regular analysis. Using this process, the optimal operating conditions with respect to the leached Pb concentration would be as follows: (1) Plant K1(injection mode operation)--87 tons of scrap iron, 1.4 tons of lime, 0.4 ton of coke, and 0.9 ton of MIFA; (2) Plant K2(injection mode operation)--90 tons of scrap iron, 1.4 tons of lime, 0.7 ton of coke, and 1.1 tons of MIFA; (3) Plant K2(one-time-charge mode operation)--90 tons of scrap iron, 1.4 tons of lime, 0.9 ton of coke, and 0.7 ton of MIFA; (4) Plant K3(injection mode operation)--85 tons of scrap iron, 1.4 tons of lime, 0.7 ton of coke, and 0.9 ton of MIFA; and (5) Plant K3(one-time-charge mode operation)--87 tons of scrap iron, 1.5 tons of lime, 0.4 ton of coke, and 0.7 ton of MIFA. In this study, using MIFA from Plant K2 as an example, it was found that it required 29-35 kg of lime per ton of steel billets produced when MIFA was added. Under a normal operation of EAF steel-making, however, it required 35-45 kg of lime per ton of steel billets produced based on the past experience. In average, when MIFA is added, it needs only 32 kg of lime per ton of steel billets produced as compared to 40 kg of lime for regular steel-making. In other words, it would result in a reduction of 8 kg of lime per ton of steel billets produced by using this novel process. Based on an average monthly production of 20,973 tons of steel billets and a unit cost of 2,200 NT$ per ton of lime, a monthly saving of lime cost would be 369,125 NT$. Namely, about 4.4 million NT$ per year. In addition, it was also found that using this novel process to melt MIFA would not deteriorate the quality of steel billets and bars produced.
328

Investigations on a new high-strength pozzolan foam material

Claus, Julien 19 November 2008 (has links)
This thesis describes improvements on newly-discovered high-strength pozzolan-based materials fabricated via a low-cost chemical reaction that takes place between 90 and 115 ℃ for 3 to 24 hours. The reported results focus on pozzolan constituents acquired from Coal Combustion Products (CCPs) such as cenospheres, fly ash C and F, as well as bottom ash. The thesis reports on various types of these materials with specific gravity ranging from 0.5 to 1.6; compressive strength ranging from 300 to 3600 psi, and compressive modulus ranging from 50 to 240 ksi. In addition to their good mechanical properties under compression that are attractive for the building and construction industries, the materials further exhibit great potential for applications as energy absorption cores in sandwich construction that could extend their value in other industries including the automotive and aerospace industries. For example, the load-displacement curve exhibits a short elastic zone followed by a long load-plateau; while the materials crush through a controlled vertical cracking process. Additionally, an attempt was made to further decrease the manufacturing cost of the material by investigating incorporation of chemicals that accelerates dehydration of the mixture. One such successful chemical reported in this thesis is aluminum phosphate; while it is not conclusive how the chemical improves any major property.
329

Fly ash impact in forest ecosystems in Northeastern Germany – an assessment and regionalization approach / Flugascheeinträge in Waldökosysteme in Nordostdeutschland – ein Erfassungs- und Regionalisierungsansatz

Fürst, Christine 27 April 2010 (has links) (PDF)
The presented doctoral thesis “Fly ash impact in forest ecosystems in Northeastern Germany - an assessment and regionalization approach” intends to (a) test if the field assessment of ferrimagnetic susceptibility can be used as cost efficient method to get information on fly ash deposition impacted chemical site properties. (b) develop a regionalization approach to bridge the gap from plot-wise assessed data to spatial management information. The thesis is a follow-up of extensive research activities by the Institute for Soil Science and Site Ecology on industrial deposition in Dübener Heide and Upper Lusatian region which started in the early 1960ies and were intensified from the middle of the 1990ies on. A central topic of these research activities was the assessment of the impact of fly ash deposition on chemical soil properties. A major challenge was to transfer the assessed chemical characteristics from plot to region and to aggregate the measured values to provide an information basis, which can be used for a site potential and risk oriented forest management. This challenge was picked up by the joint research project “ENFORCHANGE” (FKZ 0330634 K, German Federal Ministry of Education and Research). The presented thesis was carried out in the frame of this project during the period 2005 - 2009. The thesis was conceived as cumulative work, which includes ten papers in total. Five articles are published in peer-reviewed journals (ISI listed, 1 paper still in revision), and five are part of books or conference proceedings. • Chapter 1 “Introduction” gives an overview on the motivation, idea and structure of the thesis. • In chapter 2 “Aims and Scope of the presented work” information on the background and frame of the study within the project ENFORCHANGE is given. • Chapter 3 “Background and State of the Art” deals with the history of fly ash deposition in the model region Dübener Heide. • Chapter 4 “Material and Methods” gives information on fly ash and presents the spatial assessment design and the hereon based approaches for up-scaling and correlation of magnetic susceptibility with selected chemical characteristics. • Chapter 5 “Results” presents results of the spatial modeling and linear regression based approach to use ferrimagnetic susceptibility for predicting the contents of selected base cations, selected acid and heavy metal cations and Black Carbon. • Chapter 6 “Discussion and Conclusions” compares the assumptions and findings in the different articles, discusses contradictory findings and open questions and provides a comprehensive evaluation of the outcomes. Final conclusions are drawn and an outlook is given. A key finding of the thesis is that the industrial complex Bitterfeld was the most important source of fly ash deposited in the model region Dübener Heide. The power plant Zschornewitz plays only a minor role contrary to the research hypothesis formulated in ENFORCHANGE. Related to the targets of the thesis, spatial variation of magnetic susceptibility was predicted with high precision by a multiple linear regression model. A slightly differing set of model parameters  according to their explanatory value for three selected depth levels  improved the prediction quality. The selection of the parameters supported understanding the major drivers for magnetic particle deposition, storage, and vertical displacement in the forest soils. Humus layer (depth level 6-10 cm), horizontal distance to Bitterfeld and soil type (Podzol, semi-terrestrial sites) were the most important variables. These variables point to a slowed-down humus dynamic, which causes the accumulation of fly ash in the humus layer. In depth level 11 – 15 cm, variables such as “aspect” gain in importance, which describe the exposure against the major wind direction and thus indicate the probability and of deposition. For the mineral horizon (depth level 21-25 cm), exposition and especially stand properties are most important. The latter gives evidence for the intensity of deposition caused by surface roughness. Therefore, the variables “coniferous” and “mixed” stands were highly relevant for the model. Variable correlations between mass susceptibility and selected base cations, acid cations and heavy metals have been found. When using a linear regression model, a prediction of Ca and Mg and of Mn was possible. The model performance was lower for Fe, Al, Cd and Black Carbon. A possible reason was the use of different plot types: the assessment of magnetic susceptibility and chemical soil properties was well harmonized at the ENFORCHANGE plots considering the sampling material and sampling location. A comparable harmonization could not be achieved at a number of monitoring plots, which were included into the analysis to broaden the data base. Comparing the results from the linear regression model based prediction with the results achieved by multiple regression based spatial modeling lead to the conclusion that the mul¬tiple regression approach is more promising: by using other model parameters such as orographic, climatic or stand parameters together with magnetic susceptibility, the prediction quality of the deposed agents could be improved and small scale variations in nutrient potentials and risks driven by fly ash deposition could be better recognized and made available for forest management decisions. / Die vorgelegte Doktorarbeit “Fly ash impact in forest ecosystems in Northeastern Germany - an assessment and regionalization approach” (Flugascheeinträge in Waldökosysteme in Nordostdeutschland  ein Erfassungs- und Regionalisierungsansatz) verfolgte die Ziele (a) zu testen, ob sich die Erfassung der ferrimagnetischen Suszeptibilität eignet, um kosteneffizient quantitative und / oder qualitative Informationen zu den eingetragenen Flugaschemengen und den in der Folge veränderten bodenchemischen Potenzialen zu erheben (b) zu testen, ob der Indikator „ferrimagnetische Suszeptibilität“ genutzt werden kann, um Informationen über Flugascheeinträge von der punktbezogenen Erfassung auf einen regionalen Maßstab hoch zu skalieren. Grundlage dieser Zielstellungen sind Forschungsarbeiten zu der Frage der langfristigen Wirksamkeit und ökologischen Bedeutung von Industrieexhalationen auf Waldökosysteme, die am Institut bereits in den 1960ziger Jahren begonnen wurden und verstärkt seit Mitte der 1990ziger Jahre fortgeführt wurden. Auf ihrer Basis wurde die Herausforderung eines kostengünstigen und flächenbezogenen Erhebungsansatzes identifiziert und formuliert. Die vorgelegte Arbeit ordnete sich in diese Forschungsarbeiten ein und führte sie im Rahmen des Verbundforschungsvorhabens ENFORCHANGE ((FKZ: 0330634 K, Bundesministerium für Bildung und Forschung) von 2005 - 2009 fort. Die Doktorarbeit ist als kumulative Arbeit angelegt, im Rahmen derer insgesamt 10 Publikationen zusammengefasst wurden. Davon sind 5 in internationalen Journalen bereits publiziert, akzeptiert oder in einem Fall in Begutachtung; 5 weitere Publikationen wurden ergänzend und auf speziellere Themen bezogen in Proceedings oder Buchbeiträgen publiziert. Die Arbeit gliedert sich in 5 Abschnitte: • Kapitel 1 (Einleitung) gibt einen kurzen Überblick zur Motivation und Struktur der Doktorarbeit. • In Kapitel 2 (Ziele und Rahmen der Arbeit) wird der Arbeitsansatz im Rahmen des Verbundforschungsvorhabens ENFORCHANGE vorstellt. • Kapitel 3 umfasst eine Auswertung von Veröffentlichungen zur Geschichte und den ökologischen Auswirkungen der Flugascheeinträge am Beispiel der Modellregion Dübener Heide. • In Kapitel 4 wird der methodische Ansatz der Arbeit vorgestellt, der von einem Vortest zur Eignung der Erfassung der magnetischen Suszeptibilität über die Ableitung eines flächigen Erhebungsansatzes bis hin zur Frage der Modellbildung und Korrelation mit chemischen Kenngrößen reicht. • Kapitel 5 beinhaltet die Ergebnisse der räumlichen Modellbildung und der Korrelation der magnetischen Suszeptibilität mit ausgewählten Basen-, Säure- und Schwermetallkationen sowie mit Schwarzem Kohlenstoff. • Kapitel 6 diskutiert, vergleicht und bewertet die Ergebnisse der den Veröffentlichungen zugrunde liegenden Studien und zieht ein abschließendes Resumé. Ein Schlüsselergebnis der vorgelegten Arbeit belegt, dass entgegen der ursprünglichen Arbeitshypothese des Projektverbundes ENFORCHANGE nicht das mehr als 100 Jahre alte Kraftwerk Zschornewitz die wesentliche Quelle für die Flugascheeinträge in der Modellregion Dübener Heide war, sondern der räumlich entfernter gelegene, aber deutlich größere Industriekomplex Bitterfeld. Bezogen auf die Zielsetzung der vorgelegten Arbeit, konnte mithilfe multipler Regressionsverfahren und auf Basis von Feldaufnahmen der ferrimagnetischen Suszeptibilität in einem regelmäßigen Stichprobenraster ein hoch auflösendes räumliches Modell gebildet werden. Unter Berücksichtigung weiterer Modellparameter, die schrittweise hinsichtlich ihres Erklärungswertes ausgewählt wurden, konnten mikrotopographische und vegetationsbedingte Informationen genutzt werden, um die räumliche Variabilität des magnetischen Signals differenziert darzustellen. Damit ergibt sich eine Planungsgrundlage, die die bisher genutzte, auf Waldschadensansprachen basierende Stratifizierung in Zonen unterschiedlicher Eintragsintensität mit Bezug zur Planungseinheit deutlich detaillierter untersetzt. Der Versuch, auf Flugascheeintragsmengen, respektive -vorräte zu schließen ließ sich hingegen auf Basis der verfügbaren Daten nicht umsetzen. Die Korrelationsbeziehungen der von Volumen- in den Massenbezug umgerechneten Suszeptibilität mit Basen-, Säure und Schwermetallkationen sowie Schwarzem Kohlenstoff fielen heterogen aus. Eine gute Vorhersage auf Basis eines linearen Regressionsmodells konnte für Ca, Mg und Mn getroffen werden, wohingegen die Modellqualität für Fe, Al sowie Cd und Schwarzen Kohlenstoff deutlich schlechter zu beurteilen war. Dies ergab sich zum einen aus der verfügbaren Datenbasis, die keine durchgängige Harmonisierung für die Erhebungen der Suszeptibilität und der chemischen Kennwerte erlaubte. Zum anderen geht diese Erkenntnis mit Ergebnissen aus der Regionalisierung einher, die einen Einbezug weiterer Modellparameter und die Nutzung multipler anstelle linearer Regressionsmodelle nahe legt.
330

Tampa Electric Company's Big Bend Utility Plant in Hillsborough County, Florida: A Case Study

Hodalski-Champagne, Lynne M. 01 January 2015 (has links)
This is an in-depth analysis of coal fire burning power plants, their effects on human health and the environment. It also employed case study data from Tampa Electric Company’s Big Bend facility to examine environmental infractions at that facility. Tampa Electric Company’s Big Bend Utility Plant, violated the Clean Air Act, which led to a lawsuit filed by the Department of Justice on behalf of the United States Environmental Protection Agency and the Florida Department of Environmental Protection in 1997. This case study details the lawsuit, and subsequent settlement as well as Tampa Electric Company’s record of compliance since 2000. This study examines the area surrounding the plant, and impacts the facility may cause local residents and the ecosystem in this part of Florida. Several questions are explored in this case study revolving around environmental justice and environmental racism. Did the actions taken by the Department of Justice in 2000 on behalf of the Environmental Protection Agency and the people of the State of Florida through its Department of Environmental Protection fit the corporate crimes that Tampa Electric were accused of in the lawsuit? Has this company been compliant with state and federal law as required by the settlement? Finally, has the Tampa Electric Company maintained their commitment to provide environmental justice for the communities surrounding the Big Bend Utility Plant or would their actions fit a definition for the crime of corporate environmental violence?

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