The theory describing the scaling properties of quantum field theory is introduced. The symmetry principles behind scale and conformal transformations are reviewed together with the renormalisation group. A method for improving perturbative calculations of physical quantities in the infra-red limit is developed using general analyticity properties valid for all unitary quantum field theories. The infra-red limit of a physical quantity is shown to equal the limiting value of the Borel transform in a complex scale parameter, where the order of the Borel transform is related to the domain of analyticity. It is shown how this general result can be used to improve perturbative calculations in the infra-red limit. First, the infra-red central charge of a perturbed conformal field theory is considered, and for the unitary minimal models perturbed by ɸ(1,3) the developed approximation is shown to be very close to the exact results by improving only a one loop perturbation. The other example is the infra-red limit of the critical exponents of x(^4) theory in three dimensions, where our approximation is within the limits of other approximations. The exact renormalisation group equation is studied for a theory with exponential interactions and a background charge. It is shown how to incorporate the background charge, and using the operator product expansion together with the equivalence between the quantum group restricted sine-Gordon model and the unitary minimal models perturbed by ɸ(1,3), the equation obtained is argued to describe the flow between unitary minimal models. Finally, a semi-classical approximation of the low energy limit of a bosonic membrane is studied where the action is taken to be the world-volume together with an Einstein-Hilbert term. A solution to the linearized equations of motion is determined describing a membrane oscillating around a flat torus.

A commercial GC-AFS instrument has been developed and optimised for the speciation of organomercury. This instrument couples a GC oven to a modified atomic fluorescence detector via a ceramic pyrolyser. Organomercury compounds in dichloromethane solvent were directly injected through a Programmable Temperature Vaporiser Injector onto a DBl Megabore column. Once separated, the compounds eluted from the column and were atomised in the pyrolyser then detected by AFS. The direct injection technique, ceramic pyrolysis design and argon purged detector have improved previous instrument designs by enhancing and maintaining sensitivity. The instrumental limit of detection was determined to be 0.25 pg Hg absolute. Methods were developed for the extraction of methylmercury from a variety of marine samples. The techniques were validated using mussel homogenate and dogfish liver (IAEA 142, SRM 8044 and DOLT-2) certified reference materials. An interlaboratory comparision exercise was participated in and a method was developed for the detemination of methylmercury in Fucus sea plant (IAEA 140). A concentration of 0.63 ± 0.006 ng g-1 was reported. The material is now certified at 0.626 +0.139 ng g-1. Of all the participating laboratories, this was the closest result to the certified value. The instrument and methods were also applied to soil and sediment samples. Once again validation was performed with a CRM sediment, IAEA 356. Although this material has been reported to give positive artifact formation when using a steam distillation sample preparation procedure, good agreement and no artifects were observed upon analysis. A further contaminated land, an uncontaminated soil and sediment sample were also studied. For all the samples studied by GC-AFS total mercury measurements were also made following an appropriate digestion procedure and CV-AFS. A gas chromatograph was also coupled with ICP-MS and HPLC was coupled to CV-AFS as comparative techniques. Both approaches were optimised and validated with CRM's. The GC-ICP-MS had the advantage of providing additional element information and confirmed the presence of methylmercury bromide in the final mussel homogenate extract. The HPLC approach found to be much less sensitive than the GC techniques and also suffered from vapour generation interferences. The PTV injector was considered for large volume injection and thermal desorption techniques. Injector breakdown problems were overcome by optimising the conditions and solid phase adsorbent for cold splitless injection. A recovery of 70% was achieved for a 50 ul large volume injection of methylmercury chloride in DCM. This technique indicated the possibility that LVI may in the future offer increased method sensitivity.

Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2016-08-26T11:26:18Z No. of bitstreams: 0 / Made available in DSpace on 2016-08-26T11:26:18Z (GMT). No. of bitstreams: 0 / A água é um recurso essencial à vida, logo deve estar presente em quantidade e qualidade adequada para seu consumo. O presente estudo teve como objetivo avaliar a qualidade ambiental da represa Guarapiranga, Localizado em partes dos municípios de Cotia, Embu, Itapecerica da Serra, Juquitiba, São Lourenço da Serra e São Paulo e na área total do município de Embu Guaçu, este sistema tem significativa degradação em sua qualidade de água devido ao aporte de efluente doméstico e industrial aumentando o custo do tratamento e dificultando o acesso a água potável. Foram apresentados os resultados de 26 metais, 7 ânions, parâmetros limnológicos: pH, condutividade, temperatura, oxigênio dissolvido, transparência da água, obtidos a partir das amostras das coletas realizadas entre os anos de 2011 a 2013, em amostras de água na superfície, meio e fundo em 14 pontos e de sedimento de fundo nestes mesmos pontos sendo avaliando 26 metais. Os resultados de sedimento foram comparados com os valores de TEL e PEL e os resultados de água foram com os limites de estabelecidos pela resolução COMANA 357/2005. Os parâmetros limnológicos, condutividade, pH e oxigênio dissolvido ficaram fora do enquadramento da resolução do COMANA 357/05. Todas as espécies iônicas atenderam ao estabelecido pelo CONAMA 357/05, no entanto é observado um aumento das concentrações no decorrer das coletas. A serie nitrogenada assim com a relação Fe:P mostraram ser importantes parâmetros de controle do aporte da carga orgânica no reservatório. Dos 26 elementos analisados somente Al, Cu, Mn apresentaram concentrações fora do estabelecido pela resolução COMANA 357/05. Os sedimentos analisados os elementos químicos Cu, Cr, Zn apresentaram valores acima do TEL e do PEL. A partir dos resultados obtidos infere-se que o reservatório do Guarapiranga apresenta dois compartimentos distintos, um mais degradado que vai do ponto 05 a 14 que sofre os impactos da ocupação do seu entorno e um mais preservado que vai do ponto 01 a 05, sem tanta influência de ocupação urbana no seu entorno. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP