Orientador: Ana Maria Lima de Azeredo-Espin / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-09T08:21:42Z (GMT). No. of bitstreams: 1 Rosa_AlineCoelhoda_M.pdf: 1020874 bytes, checksum: 5958193e586711ee1cf0c5fe30134718 (MD5) Previous issue date: 2007 / Resumo: Este trabalho consiste na construção de uma biblioteca genômica enriquecida em microssatélites e na caracterização de dez locos polimórficos para a espécie Haematobia irritans irritans (Diptera: Muscidae), popularmente conhecida como mosca-dos-chifres, um ectoparasita de grande importância econômica para a pecuária de diversos países, principalmente no Brasil. A biblioteca genômica enriquecida em microssatélites teve um rendimento de 67% considerando-se o número de microsatélites (contendo mais de 7 repetições em série) caracterizados em um total de 109 sequências analisadas. Um rendimento de 22% foi encontrado referente à obtenção de 16 locos potencialmente informativos. Dos microssatélites identificados nesta análise, 85% possuíam motivos (CA)n e apenas 12% apresentaram motivos (GA)n, apesar da biblioteca ter sido enriquecida para ambos os motivos. Neste projeto, dez locos polimórficos de microssatélites foram descritos para a espécie H. irritans. Destes, oito locos apresentaram motivos dinucleotídeos, sendo cinco motivos (CA)n e três motivos (GA)n, além da identificação de um loco com motivo trinucleotídeo (CAA)7 e um tetranucleotídeo (CCGT)6. Entre os dez locos polimórficos, o número de alelos por loco variou entre dois e oito, tendo uma média de quatro alelos por loco, considerados um número baixo quando comparado com outras espécies de dípteros. As heterozigosidades esperada e observada apresentaram um intervalo de 0,1421-0,7702 e 0,1500-0,6750, respectivamente. Os valores de heterozigosidade também foram considerados baixos, sendo inferiores a 0,5 em pelo menos três locos. Após correção seqüencial de Bonferroni, oito locos não apresentaram desvios significativos pelo esperado por Hardy-Weinberg, bem como não foi verificado desequilíbrio de ligação entre os pares de locos. A caracterização destes marcadores microssatélites polimórficos, é potencialmente informativa para elucidar questões evolutivas envolvendo H. irritans como a compreensão da dinâmica populacional e estrutura genética desta espécie. A análise deste marcador molecular poderá orientar projetos de manejo e controle da mosca-dos-chifres / Abstract: The aim of this work was the construction of a genomic microsatelliteenriched library for the species Haematobia irritans irritans (Diptera: Muscidae), commonly known as ¿horn fly¿, an ectoparasite of great economic importance world-wide, and particularly in Brazil. Here we describe ten polymorphic microsatellite loci isolated from this species. From a complete set of 109 sequences analised, 67% contained microsatellites regions (considering sequences with more than 7 repeats). The analysis of these sequences resulted in the identification of 16 potentially informative microsatellites loci (an efficience of 22%). Regarding the composition of the microsatellites sequenced retrived in this process, 85% have (CA)n motifs and only 12% have (GA)n motifs, despite enrichment on both. From the ten polymorphic microsatellite loci isolated from H. irritans, 8 have dinucleotide motifs (5 (CA)n and 3 (GA)n), one was a trinucleotide motif (CAA)7 and one was a tetranucleotide motif (CCGT)6. The number of alleles per locus ranged from two to eight, with an average of four alleles per locus. This number of alleles was considered low if compared with other dipterans studies. The expected and observed heterozigosities ranged from 0,1421 to 0,7702 and 0,1500 to 0,6750, respectively. Heterozigosity values were considered low. In this analysis, at least three loci presented heterozigosity values under 0,5. After sequential Bonferroni correction, significant deviation from Hardy-Weinberg equilibrium was found for 2 loci. No linkage disequilibrium was observed between pairs of loci after correction for multiple tests. The characterization of these polymorphic microsatellites markers is potentially informative to investigate evolutionary questions regarding H. irritans populations by providing fundamental insights into population dynamics and genetic structure. Further projects on horn flies control and management could also benefit from this molecular marker analysis / Mestrado / Genetica Animal e Evolução / Mestre em Genética e Biologia Molecular

Orientador: Angelo Pires do Prado / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-15T15:04:17Z (GMT). No. of bitstreams: 1 Gisloti_LauraJane_M.pdf: 851756 bytes, checksum: 02ffdefd182c61c5bec5133a13b29b8f (MD5) Previous issue date: 2009 / Resumo: Este trabalho estabelece alguns aspectos biológicos e ecológicos de Neosilba perezi (Romero & Ruppel, 1973) (Diptera: Lonchaeidae), que ainda constam como desconhecidos na literatura mundial. Dentre as pragas da mandioca, a mosca-dos-brotos, N. perezi,é uma das mais observadas, atacando brotos jovens e ocasionando brotamentos laterais na região atacada. Os trabalhos referentes a essa espécie de lonqueídeo são escassos e os dados a respeito da perda de produção o ocasionada pelo ataque da mosca não são bem estabelecidos. Os objetivos deste trabalho foram caracterizar a infestação por N. perezi no sudoeste do estado de São Paulo correlacionando cada área de estudo, separadamente para cada parâmetro particular de temperatura, precipitação pluviométrica e idade das plantas; avaliar o parasitismo de larvas de N. perezi em dez genótipos de mandioca; conhecer alguns aspectos da interação de parasitoidismo associada larvas de N. perezi; além de caracterizar o desenvolvimento vital do inseto em condições controladas de laboratório e por fim e mostrar os estágios de ovo, larva e adulto. Foram realizadas análises quinzenais em cada área de estudo, no período de março de 2008 a fevereiro de 2009 para obtenção dos índices de parasitismo pelas larvas de N. perezi em brotos de mandioca e os índices de parasitoidismo por braconídeos parasitóides das larvas da mosca. Na análise dos genótipos em relação à infestação por N. perezi, estes foram plantados na área experimental do Departamento de Biologia Vegetal da Universidade de Campinas e assim o índice de infestação foi calculado para cada genótipo, no período de junho de 2008 a janeiro de 2009. O estudo do ciclo de vida da mosca foi realizado através da coleta de ovos em campo, os quais foram mantidos em uma dieta elaborada neste trabalho a qual possibilitou o desenvolvimento total, de ovo a adulto de N. perezi. A dinâmica populacional da mosca-dos-brotos na região estudada está correlacionada, separadamente, com a temperatura, com a pluviosidade e com a idade da plantas, de forma que temperatura acima de 23°C, ou pluviosidade relativamente alta ou ainda idades tardias das plantas afetaram negativamente a população deste inseto. O genótipo "IAC Caapora 105-66" e o genótipo "IAC Cascuda" mostram-se menos suscetíveis à infestação por este inseto enquanto o genótipo "IAC 15" apresentou as maiores porcentagens de infestação. Quanto ao parasitoidismo por braconídeos em larvas de N. perezi, foi constatado que a porcentagem de ataque foi de 24,3% sugerindo que esta interação possa ser um importante fator na dinâmica populacional de N. perezi. Assim, estabelecemos uma descrição sucinta dos aspectos biológicos e ecológicos de N. perezi, que facilitarão estudos subseqüentes relacionados a esta família, além de elucidar alguns aspectos do parasitismo destas larvas em brotos de mandioca que poderão ser usados no esclarecimento de possíveis riscos a cultura desta planta / Abstract: This research establishes some new biological and ecological aspects of Neosilba perezi (Romero & Ruppel, 1973) (Diptera: Lonchaeidae. Among the pests of cassava, the shoot fly, N. perezi, is one of the most studied, attacking young shoots and causing side shoots in the attacked region. The researches related to this of fly are few and the data about production loss caused by the attack of the fly are not well known. The objectives of this research were to characterize infestation by N. perezi in the southwest of the State of São Paulo, Brazil by correlating separately each area, for each particular parameter of temperature, rainfall and the age of plants; evaluate larvae parasitism of N. perezi in ten manioc genotypes; know some aspects of the interaction of parasitoidism associated to N. perezi larvae ; in addition to characterize the vital development of the insect under laboratory controlled conditions and finally describe the stages of egg, larva and adult on the insect. Analyses were carried out fortnightly in each area of study from March 2008 to February 2009 in order to obtain the levels of parasitism by larvae of N. perezi in cassava shoots and parasitoidism levels by Braconidae parasitoids of the fly larvae. In analyzing the genotypes in relation to the infestation by N. perezi, these were planted in the experimental area of Plant Biology Department at the State University of Campinas and so the level of infestation was calculated for each genotype, from June 2008 to January 2009. Finally the life cycle study of the fly was carried out by collecting eggs in the field, which have been kept on a diet drawn up in this research in which made it possible for the total development, from the egg to the adult one of N. perezi. The results indicate that the fly population dynamics in the buds in the studied region is correlated, separately, with temperature, rainfall and the age of plants, so that temperature above 23ºC, or elatively high quantity of rains or even late plant ages seem negatively affect the population of this insect. Furthermore, the infestation by the fly behaved differently in the face of the different genotypes in a way that the genotype IAC Caapora 105-66 and genotype IAC Cascuda are less susceptible to infestation by this insect while the genotype IAC 15 presented the highest percentages of infestation. Regarding to parasitoidism by braconideous in N. perezi larvae was found that parasitoidism percentage was fairly high suggesting that this interaction can be an important factor in N. perezi populational dynamics. Thus, we have established a short description of biological and ecological aspects of N. perezi, which will make subsequent studies easier related to this family, as well as elucidate certain parasitism aspects of these larvae in cassava shoots which may be used in possible risks explanation to the crop of this plant / Mestrado / Mestre em Parasitologia

No presente estudo obteve-se com sucesso o compósito zeólita:magnetita usando-se como material de partida sulfato ferroso para síntese da magnetita e cinzas leves de carvão para síntese da fase zeolítica. A zeólita foi sintetizada por tratamento hidrotérmico alcalino e as nanopartículas de magnetita foram obtidas pela precipitação de íons Fe2+ em uma solução alcalina. Uma reprodutibilidade foi alcançada na preparação de diferentes amostras do nanocompósito zeolítico. O material foi caracterizado pelas técnicas de espectrometria de Infravermelho, difratometria de raios-X de pó, fluorescência de raios-X, microscopia eletrônica de varredura com a técnica de EDS, massa especifícia e área específica e por outras propriedades físico-químicas. O compósito era constituído pelas fases zeolíticas hidroxisodalita e NaP1, magnetita, quartzo e mulita das cinzas remanescentes do tratamento alcalino e magnetita incorporada na sua estrutura. A capacidade de remoção de U(VI) de soluções aquosas sobre o compósito zeólita:magnetita foi avaliada pela técnica descontínua. Os efeitos do tempo de contato e da concentração inicial do adsorbato sobre a adsorção foram avaliados. Determinou-se o tempo de equilíbrio do sistema e foram avaliados os modelos cinéticos de pseudo-primeira ordem, pseudo-segunda ordem e o modelo de difusão intrapartícula. Um tempo de contato de 120 min foi suficiente para a adsorção do íon uranilo alcançar o equilíbrio. A velocidade de adsorção seguiu o modelo cinético de pseudo-segunda-ordem, sendo que a difusão intrapartícula não era a etapa determinante do processo. Dois modelos de isotermas de adsorção, os modelos de Langmuir e de Freundlich, também foram avaliados. O modelo de Langmuir foi o que melhor se ajustou aos dados experimentais. A partir do modelo cinético e da isoterma que melhor descreveram o comportamento do sistema foi possível calcular os valores teóricos para a capacidade máxima de adsorção do U(VI) sobre o compósito zeólita:magnetita. As capacidades máximas de remoção calculadas foram de 20,7 mg.g-1 pela isoterma de Langmuir e de 23,4 mg.g-1 pelo modelo cinético de pseudo-segunda ordem. O valor experimental obtido foi 23,3 mg.g-1. / Within this work, a magnetic-zeolite composite was successfully synthesized using ferrous sulfate as raw material for the magnetic part of the composite, magnetite, and coal fly ash as raw material for the zeolitic phase. The synthesis of the zeolitic phase was made by alkali hydrothermal treatment and the magnetite nanoparticles were obtained through Fe2+ precipitation on alkali medium. The synthetic process was repeated many times and showed good reproducibility comparing the zeolitic nanocomposite from different batches. The final product was characterized using infrared spectroscopy, powder X-ray difraction, X-ray fluorescence, scanning electron microscopy with coupled EDS. Specific mass, specific surface area and other physicochemical proprieties. The main crystaline phases found in the final product were magnetite, zeolites types NaP1 and hydroxysodalite, quartz and mulite, those last two remaing from the raw materials. Uranium removal capacity of the magnetic zeolite composite was tested using bathc techniques. The effects of contact time and initial concentration of the adsorbate over the adsorption process were evaluated. Equilibrium time was resolved and the following kinectics and difusion models were evaluated: pseudo-first order kinectic model, pseudo-second order kinectic model and intraparticule difusion model. A contact time of 120 min turned out to be enough to reach equilibrium of the adsorption process. The rate of adsorption followed the pseudo-second order model and the intraparticle diffusion didnt turned out to be a speed determinant step. Two adsorption isotherms models, the Langmuir model and the Freundlich model, were also evaluated. The Langmuir model was the best fit for the obtained experimental data. Using the best fitted adsorption isotherm and kinectic model, the theorical maximum adsorption capacity of uranium over the composite was determined for both models. The maximum removal capacity calculated was 20.7 mg.g-1 for the Langmuir isotherm and 23.4 mg.g-1 for the pseudo-second order model. The experimental value attained was 23,3 mg.g-1.

O presente trabalho reúne elementos para projeto de precipitadores eletrostáticos, com dados levantados de cinzas volantes provenientes da combustão de gases em caldeiras de carvão mineral. Os objetivos desta pesquisa são construir um dispositivo padronizado para medição da resistividade ôhmica de materiais, levantar dados de resistividade ôhmica das cinza volantes de carvão mineral utilizado no Brasil e, com estes dados, listar recomendações sobre cuidados no dimensionamento de precipitadores (cálculo da área de captação), quando este equipamento é posicionado após uma caldeira que queima o carvão mineral nacional. A metodologia utilizada foi baseada em norma americana ASME, em que o pó (material a ser testado) é colocado sobre eletrodos de descarga e de coleta, uma alta tensão elétrica é aplicada até atingir a tensão de ruptura elétrica e neste instante é medida a resistividade. A construção do experimento e procedimento de execução foram seguidos conforme esta norma. O material de teste foi coletado de precipitadores eletrostáticos existentes na região Sul do Brasil, onde o carvão mineral tem seu uso freqüente. Os resultados apresentaram baixos valores para resistividade da cinza volante nacional, se comparados com resultados de carvões de outros países. Sua variação em função da temperatura segue a tendência de cinza volantes de outros países, ou seja, aumento da resistividade ôhmica com o aumento da temperatura. Foram realizados também experimentos com material retirado de precipitadores eletrostáticos acoplados a caldeiras de biomassa, que forneceram valores de resistividade ainda menores do que os do carvão mineral nacional. O material de teste, composição química e processo de coleta foram totalmente caracterizados, disponibilizados e uma análise completa pôde ser realizada, fato inédito no Brasil. Esses resultados permitiram listar recomendações visando o projeto de precipitadores eletrostáticos acoplados a caldeiras que queimam carvão mineral nacional. / This report is a collection of elements to be used in the design of Electrostatic Precipitators, with experimental data of fly ashes from combustion gases of Mineral Coal Fired Boilers. The aims of this research are to construct a standard device to measure the ohmic resistivity of materials, to get data of ohmic resistivity of fly ashes from mineral coals used in Brazil and with this data, to list recommendations about the key points to size electrostatic precipitators (calculation of specific collection area), when this equipment is arranged after one boiler that burns Brazilian mineral coals. The method used was based on the ASME Standard, in which the fly ash (material to be tested) is put between the discharge and the collecting electrodes, a high electrical tension is applied until the electrical break down tension to be reached; at this moment, the resistivity is measured. The construction of this device and the experimental procedure were conducted according to this standard. The tested materials were collected from existing Electrostatic Precipitator of South of Brazil, where the mineral coal is commonly used. The results indicated low values of ohmic resistivity of the Brazilian fly ashes, if compared to results of coals from other countries. Its variation with the temperature has the same behavior of fly ashes from other countries, i.e., the ohmic resistivity increases when the temperature increases. It was also executed tests with particulate materials from electrostatic precipitator of biomass boiler whose ohmic resistivity is lower than the Brazilian mineral coal. The tested material, chemical composition, and collecting process were totally described, available and a full analysis can be executed; these data are inedita in Brazil. These results allow to list the recommendations to design Electrostatic Precipitators for Brazil Mineral Coal Fired Boilers.

Orientador: Arício Xavier Linhares / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-19T03:28:23Z (GMT). No. of bitstreams: 1 Stoppa_LailaSilvaLeoneldeAvila_M.pdf: 2902278 bytes, checksum: 52b99920b1d3a2f1d669e4cff58d53fe (MD5) Previous issue date: 2011 / Resumo: A entomologia forense utiliza principalmente dados de insetos necrófagos para estimar o intervalo pós-morte (IPM). A oviposição destes insetos pode ser influenciada por vários fatores, tais como se o corpo está envolto por algum material, se está enterrado, carbonizado, em ambiente aberto ou fechado, podendo assim alterar o cálculo do IPM. O propósito deste trabalho foi estudar as diferenças na exposição de carcaças abrigadas e desabrigadas, no processo de decomposição, na atratividade e oviposição pelos artrópodes e na sucessão entomológica. A influência do modo de exposição das carcaças em relação à abundância das espécies que as coloniza também foi reportado. Os experimentos foram realizados em duas estações do ano, quente e úmida e na seca e fria. Foram utilizadas três carcaças de suínos (Sus scrofa L.), fêmeas de aproximadamente 10kg, em cada estação. A fim de se evitar a predação por animais de grande porte, as carcaças foram colocadas em gaiolas de ferro e expostas em um arboreto, nas dependências da UNICAMP, situado entre os paralelos 22°48'57"S, 47°03'33"W, 640 metros de altitude. Uma carcaça ficou desabrigada (controle) e as outras duas (réplicas) dentro de barracas de camping de dimensões 2,05m x 1,45m x 1,00m, abrigadas, uma na sombra e outra no sol. Os insetos adultos alados foram coletados com puçá e os imaturos direto da bandeja de cada carcaça, todos os dias no mesmo horário. Amostras de solo também foram coletadas no local do experimento ao redor de cada carçaca. Foi obtido um total de 37.787 espécimes pertencentes ao Filo Arthropoda, distribuídos em 11 diferentes ordens, sendo que desse total 8.842 foram coletados e 28.945 foram criados, ou seja, os imaturos foram levados ao laboratório e mantidos em câmaras de criação (±26°C) até sua emergência. Dos coletados, 92,2% pertencem à ordem Diptera, onde se destacaram as famílias Calliphoridae (28,7%) e Muscidae (34,6%). Outras ordens coletadas foram Coleoptera (4,5%), Hymenoptera (1,9%), Lepidoptera (0,5%) e Hemiptera (0,3%). Foram coletados menos de 1% de artrópodes ocasionais pertencentes às ordens Blattodea, Mantodea e Neuroptera, além de Acari, Opiliones e Araneae. Dos criados, 99,8% pertenciam a ordem Diptera onde se destacaram as famílias Calliphoridae (93,2%) e Muscidae (5,4%). A ordem Coleoptera foi responsável por 0,2% restantes. Considerando-se diferentes tipos de exposição, observou-se diferença no tempo de decomposição, modo e duração de cada estágio entre as carcaças, sendo que na carcaça controle a decomposição foi muito mais rápida e obteve maior abundância de artrópodes que nas carcaças abrigadas, embora a composição de espécies ter sido similar em todas elas. Fatores abióticos exerceram influência retardando ou acelerando a atividade dos insetos necrófagos nas carcaças. Chrysomya albiceps foi à espécie mais abundante e juntamente com Hemilucilia segmentaria e Peckia (Euboetcheria) collusor podem ser considerados indicadores forenses para estimativa de IPM, enquanto Hemilucilia segmentaria e Hemilucilia semidiaphana podem ser usadas como indicador forense para região de mata, modo de exposição e estação fria e seca. Tais resultados demonstram a importância da utilização da entomologia forense como ferramenta nas investigações legais / Abstract: Forensic Entomology uses data, mainly from carrion insects, to estimate the Post Mortem Interval (PMI). The oviposition pattern of these insects can be influenced by several factors, such as the presence of materials in the vicinity of the body, whether the corpses are buried, burned or disposed in open or closed environments, etc. These factors can affect the PMI estimate. The purpose of this work was to study the differences in decomposition, attractiveness and oviposition patterns between carcasses exposed in sheltered and open environments. The influence of the mode of exposure in relation to the abundance of the species that colonized were also been studied. The experiments were conducted in two seasons: warm and wet (summer), and dry and cool (winter). Three carcasses of female pigs (Sus scrofa L.), weighing aproximatelly 10 kg were used per season. The carcasses were placed in iron cages in order to avoid predation by large animals, and exposed in an arboretum located on the State University of Campinas campus, (22 ° 48'57 "S 47 ° 03'33" W), at 640 m above sea level. One pig was placed in and unsheltered area (control) and the other two were exposed inside camping tents measuring 2,05 m x 1,45 m x 1,00 m. One tent was set in a shaded area and the other one was places under direct sunlight. Adult insects visiting the carcasses were collected with an insect net. The immatures leaving the carcasses to pupate were collected in trays placed beneath each carcass, taken to the laboratory, reared at 26 °C in growth chambers until adult emergence, and identified. Soil samples were also collected at the site of the experiment around each carcass. A total of 37.787 specimens of Arthropoda was obtanined, distributed in 11 different orders. Of this total, 8.842 were collected and 28.945 were reared from the collected larvae. Diptera totaled 92.2% of the adults collected (Calliphoridae-28.7% and Muscidae-34.6%). The other collected orders were: Coleoptera (4.5%), Hymenoptera (1.9%), Lepidoptera (0.5%) and Hemiptera (0.3%). Les than 1% of occasional arthropods belonging to the orders Blattodea, Mantodea and Neuroptera, and Acari, Opiliones and Araneae were also collected. More than 99% of the reared insects belonged to the order Diptera, Calliphoridae (93.2%) and Muscidae (5.4%) were the most abundant families. The order Coleoptera accounted for the remaining 0.2%. Considering the different types of exposure, there was a difference in the decomposition time, mode and duration of each decomposition stage of the carcasses. The decomposition process in the control carcasses was much faster and had greater abundance of arthropods in the sheltered carcasses, but species composition was similar. Abiotic factors exerted influence by delaying or accelerating the activity of insects in the carcasses. Chrysomya albiceps was the most abundant species and, together with Hemilucilia segmentaria and Peckia (Euboetcheria) collusor can be considered important indicators in the estimation of PMI, while Hemilucilia semidiaphana and Hemilucilia segmentaria can be also used as indicators for wooded areas, mode of exposure and season. These results evidence the importance of using forensic entomology as a tool in legal investigations / Mestrado / Parasitologia / Mestre em Parasitologia

Low level nuclear waste arising from UK nuclear sites, research establishments, hospitals and industry is currently disposed of at the Drigg Disposal Facility in Cumbria. Waste is packed into steel canisters before being compacted and grouted into larger steel storage containers. The aqueous chemistry of wastes, especially radionuclides, in the presence of grout material is of major interest. The gout used at the Drigg site is a mixture of Ordinary Portland Cement and Pulverised Fly Ash additive, from which ingressing water will leach high levels of calcium, sodium and potassium and produce waters of a high pH. Aerobic environments are expected to dominate over the early period of the vault life, after which the combined effect of canister corrosion and microbial activity will lead to anaerobic conditions. After a much longer period (100,000 years) anaerobic conditions may cease and yield once again an aerobic environment where migration of radionuclides may be sorption-controlled rather than on hydroxide precipitation at high pH. Work has been performed under both aerobic and anaerobic conditions to study uranium solubility in the presence of complexing ligands that may be present in the waters of the nearfield of a low-level waste disposal vault. Eleven ligands have been investigated: carbonate, phosphate, chloride, sulphate, acetate, citrate, EDTA, NTA and organic matter- humic acid, fulvic acid and iso-sacchannic acid. Anaerobic conditions were achieved by two different procedures; the first used ferrous ions in hydroxide solution and the second used dithionite in hydroxide solution. Both methods produce reducing electrode potentials and high pH. Computer software has been used to model experimental results, thereby predicting uranium solubilities and speciation, and to propose new formation constants to fit the experimental results more closely. Studies have also been perforined to measure uranium sorption by grout material at high pH in the presence of the above ligands. This work makes a significant contribution to the understanding of uranium solubility and speciation in waters. at high pH and under conditions relevant to low level nuclear waste disposal.

>Magister Scientiae - MSc / Most of the world's energy production is still mainly achieved by the combustion of coal in power stations. Coal fly ash is the inevitable waste product that accumulates to metric ton volumes each year. These vast volumes pose a problem in the disposal of the coal fly ash which conventionally is loaded onto ash dumps located near the coal power stations. Alternatives need to be investigated for the use of the coal fly ash in applications that would make the coal fly ash useful and thereby help to mitigate the environmental strain imposed by conventional ash dump disposal. This study focussed on investigating the extraction of Si and Al from CFA. The investigation into the removal of the magnetic iron oxide content and calcium content from coal fly ash was also carried out to enhance the extraction of the Si and Al from CFA e.g. the removal of calcium was attempted to promote the leaching of aluminium from the ash. The rationale for this process was that by removing and recovering these major constituent elements from the ash, it would be easier to concentrate and isolate the trace elements especially the rare earth elements that are present in the CFA. Coal fly ash sourced from Matla coal power station was characterised using x-ray diffraction to determine the mineral phases present in the raw coal fly ash and elemental composition determined by x-ray fluorescence and laser ablation ICP-MS. The main mineral phases in coal fly ash were determined to be quartz, mullite, magnetite and lime (CaO). Magnetic extraction was initially carried out on the coal fly ash to remove the iron rich magnetic material. Extraction tests were then performed on the coal fly ash using alkaline and acidic media namely; NaOH, HCl and H₂SO₄. The extraction tests were assessed and a sequential extraction experimental procedure developed to achieve the highest extraction yield for Si, Al, Fe, Ca, and Mg from the coal fly ash. Lastly the rare earth element content in coal fly ash was tracked from the beginning till the end of the sequential extraction procedure to ascertain whether the rare earth elements partitioned to the leachates or the solid residues. The total element recoveries for Al, Si, Ca Fe, Mg were 53.36 %, 39.96 %, 93.8 %, 25.6 % and 67.3 % respectively using the sequential extraction procedure developed in this study. The rare earth elements contents were not affected by the sequential extraction procedure and on the whole remained in the solid residues at the completion of the sequential extraction, resulting in a residue with enriched levels of recoverable or extractable REE content after the removal of the major oxides from the CFA. The lowest enrichment being approximately 5 % for Thulium and the highest being approximately 76 % for Erbium.

M.Tech. / In this study, ethylene vinyl acetate-fly ash (EVA-FA) composites were explored for the removal of phenols from water. The composites were prepared from EVA and untreated and acid treated fly ash via the melt-mixing technique using a rheomixer. The fly ash was characterised by X-ray fluorescence (XRF), X-ray diffraction (XRD) scanning electron microscopy (SEM) and Brunauer, Emmett and Teller (BET) surface area measurement. Fly ash is composed mainly of SiO2, Al2O3, CaO and Fe2O3. Modified fly ash gave a better specific surface area of 0.4180 m2/g, while 0.0710 m2/g was obtained for unmodified fly-ash due to the disintegration of the outer layer which resulted in smaller particles, hence a larger surface area. EVA-FA composites were prepared from fly ash loadings of 3 to 20% and further characterised by XRD, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and SEM. XRD showed successful incorporation of fly ash into the EVA matrix through the appearance of fly ash diffraction peaks on the EVA-FA composite diffraction pattern. The incorporation of fly ash into the EVA matrix resulted in an improvement in the thermal stability of EVA, but did not have an effect on the melting temperature of the composites. However, a decrease in crystallisation temperature was observed. SEM micrographs revealed uniform dispersion of fly ash particles in the polymer matrix. Adsorption studies were performed using p-chlorophenol (PCP), 2,4,6-trichlorophenol (TCP) and p-nitrophenol (PNP) as model pollutants. An increase in adsorption efficiency of EVA-FA composites was observed as fly ash loading was increased from 3 to 10%. Between 10 and 20% fly-ash loading the removal efficiencies remained constant. The effect of contact time, pH and initial concentration was investigated. Polymer composites prepared from unmodified fly ash resulted in a higher adsorption capacity of phenols. The maximum uptake of PCP was 0.18 mg/g and that for TCP was 0.19 mg/g over a pH range of pH 3 to 5 and after contact time of 8 h. However, the adsorption capacity of 0.30 mg/g for PNP was achieved at pH 5 after a period of 10 h. Equilibrium adsorption data were evaluated using Langmuir and Freundlich adsorption isotherm models. There was no significant difference in the correlation coefficients (R2) from both models for the adsorption of PCP and TCP. However, the equilibrium adsorption data for PNP were better described by the Langmuir adsorption isotherm model. The kinetics data were analysed by pseudo-first-order and pseudo-second-order kinetic models. The pseudo-second-order kinetics model gave better correlation coefficients (> 0.9) for the adsorption of the phenols and the amount adsorbed at equilibrium was comparable to that calculated from the pseudo-second-order equation. Desorption studies were performed using NaOH solution with varying concentrations (0.1 to 0.3 M) and the studies revealed that PNP was the most difficult to be desorbed. Approximately 75% of PNP was recovered while 82% of PCP and 84% of TCP were recovered.

Magister Scientiae - MSc / This study evaluated SO4 2- removal from circumneutral mine water (CMW) collected from Middleburg coal mine using coal FA collected from Hendrina power station. The following parameters were investigated: the effect of the amount of FA, the effect of the final pH achieved during treatment, the effect of the initial pH of the mine water and the effect of Fe and Al on SO4 2- removal from mine water. The precipitation of ettringite at alkaline pH was evaluated to further reduce the SO4 2- concentration to below the DWAF limit for potable water. Removal of SO4 2- from mine water was found to be dependent on: the final pH achieved during treatment, the amount of FA used to treat the mine water and the presence of Fe and Al in the mine water. Treatment of CMW using different CMW:FA ratios; 5:1, 4:1, 3:1, and 2:1 resulted in 55, 60, 70 and 71 % SO4 2- removal respectively. Treatment of CMW to pH 8.98, 9.88, 10.21, 10.96, 11.77 and 12.35 resulted in 6, 19, 37, 45, 63 and 71 % SO4 2- removal respectively. When the CMW was modified by adding Fe and Al by mixing with Navigation coal mine AMD and treated to pH 10, 93 % SO4 2- removal was observed. Further studies were done to evaluate the effects of Fe and Al separately. Treatment of simulated Fe containing AMD (Fe-AMD) to pH 9.54, 10.2, 11.8, and 12.1 resulted in 47, 52, 65, and 68 % SO4 2- removal respectively. When Al containing AMD was treated to pH 9.46, 10.3, 11.5 and 12 percentage SO4 2- removal of 39, 51, 55 and 67 % was observed respectively. / South Africa

Magister Scientiae - MSc / It was hypothesized that South African FA and brine could sequester CO2 through mineral carbonation. A statistical approach was undertaken to optimize the % CaCO3 formed from FA/brine/CO2 interaction with input parameters of temperature, pressure, particle size and solid/liquid ratio (S/L) being varied. The ranges adopted for the input parameters were: temperature of 30 ºC or 90 ºC; pressure of 1 Mpa or 4 Mpa; four particle sizes namely bulk ash, > 150 μm, < 20 μm and 20 μm- 150 μm particle size range; S/L ratios of 0.1, 0.5 or 1. The FA/ brine dispersions were carbonated in a high pressure reactor varying the above mentioned input parameters. The fresh Secunda FA of various size fractions was characterized morphologically using scanning electron microscopy, chemically using X-ray fluorescence and mineralogically using qualitative X-ray diffraction. The carbonated solid residues on the other hand were characterized using quantitative X-ray diffraction, scanning electron microscopy, thermal gravimetic analysis and Chittick tests. The raw brine from Tutuka together with the carbonation leachates were characterized using inductively coupled mass spectrometry and ion chromatography. Total acid digestion was carried out to evaluate the differences in the total elemental content in both the fresh ash and the carbonated solid residues. The results suggested that South African FA from Secunda belongs to class F based on the CaO content as well as the total alumina, silica and ferric oxide content, while the RO brine from Tutuka were classified as NaSO4 waters. / South Africa