Orientador: Marcos Fernando de Souza Teixeira / Resumo: Os principais objetivos desse trabalho, que envolve importantes áreas da ciência como química, física nuclear e geologia, são quantificar as atividades de gás radônio e concentração de chumbo total em regiões específicas do Brasil e Portugal, além de elaborar mapas indicativos do teor geogênico desses elementos em regiões de falhas geológicas. As zonas de falha geológica são regiões onde ocorreram fraturamentos e esmagamentos intensos de rocha e possuem a característica intrínseca de liberarem maior quantidade de gás Rn. As regiões de falhas também podem ser alvo de estudos voltados à quantificação de metais, principalmente de chumbo (Pb) por estar inserido na série natural de decaimento radioativo do urânio. As amostras de solo e rocha foram coletadas de acordo com estudos prévios em dois cenários, o primeiro abrange regiões específicas de Portugal (Sangemil e Oliveira do Hospital) e o segundo cenário refere-se ao município de Presidente Prudente, estado de São Paulo, Brasil. As amostras foram analisadas utilizando-se de algumas técnicas como: espectrometria com detector de germânio de alta resolução, onde quantificou-se as atividades de 235U, 228Ac, 226Ra, 210Pb, 212Pb, 214Pb, 212Bi, 214Bi, 234Pa, 208Tl e 40K; medidor Alpha Guard instalado em contentores metálicos onde determinou-se o coeficiente de emanação por meio das concentrações de Rn e Ra; medidor Alpha Guard e câmara de ionização que possibilitou quantificar Rn e U in situ, análise eletroquímica via técnica de volta... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The main objectives of this work, that involve important areas of science such as chemistry, nuclear physics and geology, are to quantify uranium, radon gas and total lead concentration in specific areas from Brazil and Portugal, and to prepare geogenic maps indicating the content of these elements in geological faults regions. The geologic fault zones are regions where fractures and intense crushing of the rock occurred, with varying thickness in centimeters until kilometers. Due to the intrinsic characteristic of releasing a larger amount of Rn gas, geological fault regions can also be the target of studies aimed at the quantification of metals, mainly lead (Pb), as it is included in the natural decay series of uranium. Soil and rock samples were collected according to previous studies in two scenarios, the first covering specific regions of Portugal (Sangemil and Oliveira do Hospital) and the second scenario refers to Presidente Prudente municipality, state of São Paulo, Brazil. The samples were analyzed using some techniques such as HPGe detector, where the activities of 235U, 228Ac, 226Ra, 210Pb, 212Pb, 214Pb, 212Bi, 214Bi, 234Pa, 208Tl and 40K were quantified; Alpha Guard installed in metal containers where the emanation coefficient was determined by the Rn and Ra concentrations ; Alpha Guard and ionization chamber that possibilited to quantify Rn and U in situ and Anodic Stripping Voltammetry that the total Pb content of the samples was measured. The radionuclides acti... (Complete abstract click electronic access below) / Doutor

The purpose of this work is split into two categories, the first was to analyse the application of real-time Physics Engine software libraries for use in calculating a geological numerical model. Second was the analysis of the applicability of glyph and implicit surface based visualization techniques to explore fault systems produced by the model. The current state of the art in Physics Engines was explored by redeveloping a Discrete Element Model to be calculated using NVIDIA's PhysX engine. Analyses regarding the suitability of the engine in terms of numerical accuracy and developmental capabilities is given, as well as the definition of a specialised and bespoke parallelisation technique. The use of various glyph based visualizations is explored to define a new standardised taxonomy for geological data and the MetaBall visualization technique was applied to reveal three dimensional fault structures as an implicit surface. Qualitative analysis was undertaken in the form of a user study, comprising of interviews with expert geologists. The processing pipeline used by many Physics Engines was found to be comparable to the design of Discrete Element Model software, however, aspects of their design, such as integration accuracy, limitation to single precision floating point and imposed limits on the scale of n-body problem means their suitability is restricted to specific modelling cases. Glyph and implicit surface based visualization have been shown to be an effective way to present a geological Discrete Element Model, with the majority of experts interviewed able to perceive the fault structures that it contained. Development of a new engine, or modification of one that exists in accordance with the findings of this thesis would result in a library extremely well suited to the problem of rigid-body simulation for the sciences.