Zugl.: Giessen, Univ., Diss., 2009

Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 211-215).

Thesis (Ph. D.)--Drexel University, 2007. / Includes abstract and vita. Includes bibliographical references (leaf 200).

Universiẗat, Diss., 2002--Münster (Westfalen).

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed Oct. 10, 2007). PDF text: 234 p. : ill. (some col.) UMI publication number: AAT 3259631. Includes bibliographical references. Also available in microfilm and microfiche formats.

[pt] Notícias ambientais no Brasil foram dominadas através de derramamentos de óleo nos últimos anos. Esta dissertação apresenta os resultados de um programa experimental para estudar a capacidade de desorção térmica em limpar as costas afetadas.A temperatura ambiente, os resíduos oleosos emitem metano e amônia e estas emissões tendem a aumentar com a elevação das temperaturas. Por outro lado, o teor de óleo e graxa dos resíduos oleosos cai com o aumento da temperatura e exposição prolongada.Um cobertor térmico foi construído e avaliado. Os resultados mostraram que sua eficiência é restringida a poucos décimos de centímetros abaixo da superfície do solo devido à condutividade térmica de areias. Porém, esta desvantagem poderia ser contornada colocando o termopar de controle do sistema na profundidade desejada.Finalmente, a desorção térmica in situ parece ser um sistema único para a limpeza de resíduos oleosos. É simples, rápido e evita todo o incômodo associado à escavação de solo para disposição ou limpeza. / [en] Environmental news in Brazil has been dominated by oil spills in the past years. This dissertation presents the results of a comprehensive experimental programme on studying the ability of thermal desorption on cleaning up the affected shores.At ambient temperature, oiled debris emit methane and ammonia and these emissions tend to increase with rising temperatures. On the other hand, oil&grease content from oiled debris falls with rising temperature and prolonged exposure.A thermal blanket was designed, built and evaluated herein. Results have shown that its efficiency is restricted to few tenths of centimetres below the ground surface due to the thermal conductivity of sands. However, this drawback could be overcome is the control thermocouple of the system is positioned at the desired depth.Finally, in situ thermal desorption seem to be an unique system for cleaning debris from oil spills. It is simple, fast and avoids all the harassment associated to digging up the soil for disposal or cleanup.

Humic substances (HS) are described as a complex mixture of organic molecules formed by incomplete decomposition of plant, animal and microbial matter. They are found in soil, water and air and have many environmental roles, e.g. water retention and metal ion binding in soil. Despite their importance, the molecular composition of HS is poorly understood. This is mostly because of an inability to separate individual molecules from these complex mixtures and then characterise them by standard analytical methods such as NMR and MS. In order improve the understanding of these important mixtures I have studied them using a high-resolution analytical method, Fourier transform ion-cyclotron resonance mass spectrometry (FTICR MS). Initial efforts focussed on testing the, fast, automated data analysis of the large data sets produced. Two pieces of software were compared and the reliability of the formulae assigned by these was critically evaluated. This confident formula assignment was then applied to study the consequences of different ionisation and instrumental parameters on the mass spectra obtained. The use of laser desorption/ionisation (LDI) without the need to employ a matrix required in matrix assisted laser desorption/ionisation (MALDI) was explored. A comparison of LDI and electrospray ionisation (ESI) FTICR MS of natural organic matter samples showed that these methods ionise complementary sets of compounds. The LDI ionised compounds were characterised as aromatics or condensed aromatics and compounds belonging to lower oxygen classes (maximum number at O8), while ESI ionised higher oxygen classes (maximum number at O16) with a vast majority of compounds classified as aliphatic based on their modified aromaticity index. MALDI and LDI spectra produced very similar data with over 90% matching formulas implying that fragmentation is not caused by LDI, as taught previously. My work showed that to maximize the coverage by FTICR MS of the molecular space occupied by these complex mixtures, multiple ionization methods must be used. As a particularly convenient and readily deployable ionization technique, LDI should be included in standard analytical protocols for FTICR MS analysis of NOM. I have explored different parameters and experimental settings to obtain a fuller coverage of the molecular space of NOM, this showed that different experimental conditions enhance peak intensities in different m/z regions of the FTICR MS spectra and that information can be obtained outside of the narrow 200-700 m/z window. To gain chemical and structural information about humic substances beyond what is currently known, experiments aimed to label HS using different isotopes and at specific sites were developed and tested. Two methylation reactions were of particular interest. A methylation that selectively targeted carboxylic acid groups and incorporated deuterium in the form of CD3 groups. An international standard, Suwannee River fulvic acid, was methylated and analysed by high-resolution mass spectrometry in order to gain information on the number and distribution carboxylic acid groups. This proved challenging due to the reactivity of the unknown molecules being difficult to determine in advance. Additionally, the peak separation being reduced to as low as 1.5 mDa pushed the instrument resolution and assignment confidence to their limits. The second methylation method explored used 13CH3I, a nonselective agent reacting with any labile proton, particularly attaching 13CH3 groups to carboxylic, phenolic and alcoholic OH groups. I prepared a methylated sample of fulvic acid from a Red Moss raised bog (Balerno, near Edinburgh) ready for analyses by high field NMR. This investigation yielded structures of a number of phenolic compounds for the first time by NMR.

Made available in DSpace on 2014-10-09T12:54:50Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:59Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN/CNEN-SP

Orientador: Ademércio Antonio Paccola / Banca: Wolmar Apparecida Carvalho / Banca: Sandra Maria Barbalho / Banca: Silas Macedo Silva / Banca: Rosana Cavalcante dos Santos / Resumo: O processo de solubilização, dissolução de minerais do solo e suas interações com os processos de adsorção e dessorção de fosfato são de alta importância devido às possibilidades de otimização no processo de adubação do solo para o plantio. Alguns autores sugerem que a dissolução de ferro nos solos ocorre por redução microbiana e complexação, interferindo diretamente no processo de adsorção e dessorção do fosfato. O objetivo deste trabalho foi investigar a relação existente entre liberação de ferro, a neoformação de óxidos de ferro e adsorção e dessorção de fosfato em um Latossolo Vermelho distrófico de região Tropical Úmida. A relação foi estudada em solos sob diferentes tipos de ocupação: cana de açúcar, café, milho, reflorestamento de eucalipto e floresta natural. Amostras de solo foram coletadas nos horizontes A e B, tratadas com solução de sacarose a 3% e mantidas em repouso. O processo redox ocorreu em todas as amostras tratadas o que foi comprovado pela análise de pH onde se obteve uma acidificação do meio e posterior aumento do pH, indicando o estabelecimento de um equilíbrio químico do processo, mantendo assim o pH estável. Análises quantitativas de ferro, zinco, cobre, manganês e fósforo foram realizadas no solo natural, no solo sob tratamento e na fase líquida das amostras. A estes solos foram adicionadas duas concentrações de fosfato: 200 mg.dm3 e 400 mg.dm3 e calculadas as adsorções. A comparação dos resultados destas análises mostrou que a fixação de fósforo foi maior nos solos submetidos ao tratamento. Isto pode ser explicado pela decomposição microbiana dos compostos orgânicos, na interface com a atmosfera oxidante, que provocou a precipitação dos óxidos e hidróxidos dos metais onde os íons fosfato foram fixados pelos óxidos e hidróxidos reprecipitados. / Abstract: The solubilization process, minerals dissolution and its interactions with the phosphate adsorption/desorption processes are of high importance due to the possibilities of improvement in the process of the soil manuring in the plant crops.Some authors suggest that the iron dissolution in the soils occurs by microbial reduction and complexation, interfering directly in the phosphate adsorption /desorption process.The purpose of this work was to investigate the existent connection between the iron liberation, the neoformation of iron oxides and the phosphate adsorption/ desorption in a "Latossolo Vermelho Distrófico"of humid tropical region.This connection was studied in soils by different crops: sugar cane, coffee, corn, reforestation with eucalyptus and natural forest. Soil's samples were collected in A and B horizon, treated with sucrose 3% solution and maintained in repose.Redox process occurred in all the treated samples, what was proved by the pH analysis, in where were obtained some acidification of the environment and subsequent pH increase, indicating the establishment of a chemical balance of the process, maintaining like this the pH stable. Quantitative analyses of iron, zinc, copper, manganese and match were accomplished in the natural soil, in the soil under treatment and in the liquid phase of the samples.Two phosphate concentrations: 200 mg.dm3 and 400 mg.dm3 were added to these soils and the adsorptions were calculated. The comparison of these analyses results shows that the phosphorous fixation was higher in the soils submitted to the treatment. This can be explained by the microbial decomposition of the organic compounds, in the interface with the oxidant atmosphere, which nettled the precipitation of the oxides and hydroxides of the metals in where the phosphate ions were fixated by oxides and hydroxides reprecipitated. / Doutor

Made available in DSpace on 2014-10-09T12:54:50Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:59Z (GMT). No. of bitstreams: 0 / Ímãs sinterizados foram produzidos utilizando o pó obtido pelo processo de Hidrogenação, Desproporção, Dessorção e Recombinação (Processo HDDR). O processo HDDR na produção de ímãs sinterizados foi adotado visando uma redução no tempo de moagem e investigar seu efeito nas propriedades magnéticas e na microestrutura. As ligas utilizadas nesse trabalho apresentaram a seguinte composição: Pr14FebalCoxB6Nb0,1 (x= 0; 4; 8; 10; 12; 16) e Pr20,5Fe72,5B5Cu2,0 (utilizada como aditivo de sinterização). O pó HDDR foi utilizado para produzir ímãs sinterizados com uma mistura dessas ligas (liga principal + aditivo), nas seguintes proporções: 80 % em peso da liga principal e 20% em peso do aditivo de sinterização (Pr20,5Fe72,5B5Cu2,0). O processo de decrepitação por hidrogênio (Processo HD) na produção de ímãs também foi utilizado nesse trabalho para efeito de comparação (tempos de moagem: 20, 15, 10 e 5 horas). A temperatura e o tempo de sinterização foram mantidos constantes para todos os ímãs (1050 º C por 60 minutos). O ímã sinterizado produzido pelo processo HD apresentou melhor remanência (1220 mT).Esse ímã foi fabricado com a liga Pr14Fe75,9B6Co4Nb0,1 utilizando um tempo de 20 horas de moagem. A melhor coercividade intrínseca foi obtida com a liga Pr14Fe75,9B6Co4Nb0,1 em ambos os processos, de 1020 mT para o processo D (5 horas de moagem) e de 1190 mT para o processo HD (20 horas de moagem). As microestruturas dos ímãs permanentes foram analisadas por microscopia eletrônica de varredura (MEV) e por dispersão de energia de raios-X (EDS). / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN/CNEN-SP