In this thesis we study certain geometric properties of Müntz spa- ces as subspaces of continuous functions. In the first chapter we present some of the most important examples of the Müntz type theorems. Namely, we present the classic Müntz theorem and the Full Müntz theorem in the setting of the space of continuous functions on the interval [0, 1]. We also mention several extensions of these theorems to the case of continuous functions on the general interval [a, b] as well as an analogy of the Full Müntz theorem for the Lp ([0, 1]) spaces. The second chapter is divided into three sections. In the first section we present some definitions and well-known theorems of Choquet theory, which we use to characterize the Choquet boundary of Müntz spa- ces. In the second section we present the result concerning non-reflexivity of Müntz spaces as well as its corollary describing the non-existence of an equiva- lent uniformly convex norm on these spaces. In the third section, we concern ourselves with the question of Müntz spaces having the Radon-Nikodym pro- perty. As a main result of this part we show that a certain type of Müntz spaces doesn't have the Radon-Nikodym property. The final chapter contains a summary of some known results as well as open problems related to the theory of Müntz spaces....

The thesis is focused on measurement and assessment of absorbed doses of radiation in caves of the Czech Republic, out of which some exhibit high activity concentration of radon in air. This thesis presents an analysis and recommendations based on measurement results obtained in the underground caves over the past 10 years. The focus is on defining the sources of irradiation within the cave environment (and in areas used for speleotherapy), considering their potential health effect, including the variable dependence of external and internal irradiation influences. All of the measurements had as an objective to verify, and where possible improve, the existing methodology for assessing and calculating the dose from radon in underground spaces. The main issue that had to be resolved was whether a numerically specified cave factor value is applicable to all underground areas. The research measurements were carried out in all available show caves and in several underground areas, and were based on the initial results from an aerosol measurement campaign. Two caves (the Bozkov Dolomite Caves and the Zbrašov Aragonite Caves) were selected for advanced long-term measurements. A large number of long-term and short-term studies were carried out. The most important results for cave environments were: the...

The determination of plasma equilibrium profiles is necessary to evaluate the properties of the confinement and to investigate perturbation effects. Optical diagnostics can be used to determine some of these profiles. However, these diagnostics measure all emitted radiation at a solid angle that illuminate each diagnostic channel through a slit. Therefore, the real measured quantity is the emissivity integrated along the line-of-sight and some unfolding procedure, like Abels inversion, is commonly used to recover the emissivity profile. In TCABR tokamak, at the Physics Institute of the University of São Paulo, a 24-channel bolometer and a 20-channel soft X-ray optical diagnostics are used to measure the plasma emissivity in wavelength range from 1.0 to 1000 nm, depending on the used filters. In this work, a numerical simulation is used to compute the signal measured by the diagnostics for a given emissivity profile, allowing direct comparison with the experimental data and avoiding the use of the Abel\'s inversion directly and the numerical difficulties associated with unfolding procedures. By considering TCABR tokamak geometry, spatial coordinates can be related to the normalized linear coordinates of the plasma by imposing a plasma emissivity model that depends on some free parameters, allowing the emissivity resulting in each point can be calculated. Thus, the luminosity of each channel is calculated by the integral of the emissivity modeled in each line-of-sight (Radon Transformation). Emissivity model free parameters are determined by fitting calculated luminosity to measured one. We considered three types of emissivity profiles: a parabolic model in law of power, a Gaussian model and a model based on Bessel functions. We observed that the parabolic profile fits well the bolometer data, while the Gaussian profile is adequate to describe the data obtained with the soft X-ray detector. / A determinação dos perfis de equilíbrio do plasma é necessária para avaliar as propriedades do confinamento e para investigar os efeitos de perturbações. Diagnósticos ópticos podem ser usados para determinar alguns desses perfis. No entanto, esses diagnósticos medem toda a radiação luminosa emitida em um ângulo sólido que ilumina cada canal do detector através de uma fenda. Assim, a verdadeira grandeza física medida é a emissividade integrada ao longo da linha de visada. Com isso, algum procedimento de deconvolução, como a inversão de Abel, se faz necessário para obter o perfil de emissividade. No tokamak TCABR do Instituto de Física da USP, um bolômetro de 24 canais e um detector de raios-X moles de 20 canais são utilizados para medir a emissividade do plasma no intervalo de comprimento de onda de 1 a 1.000 nm, dependendo dos filtros utilizados. Neste trabalho, uma simulação numérica é usada para calcular o sinal medido pelos diagnósticos para um dado perfil de emissividade, possibilitando a comparação direta com os dados experimentais, evitando a realização da inversão de Abel e os problemas numéricos associados aos procedimentos de deconvolução. Pela consideração da geometria do tokamak TCABR, as coordenadas espaciais podem ser relacionadas com as coordenadas lineares normalizadas do plasma por meio da imposição de um modelo de emissividade para o plasma que dependa de alguns parâmetros livres, permitindo que a emissividade resultante em cada ponto possa ser calculada. Assim, a luminosidade de cada canal é calculada pela integral da emissividade modelada em cada linha de visada (Transformada de Radon). Os parâmetros livres dos perfis de emissividade são determinados ajustando-se as luminosidades calculadas em termos das luminosidades medidas. Nós consideramos três modelos de perfis de emissividade: um modelo parabólico em lei de potência, um modelo gaussiano e um modelo baseado em funções de Bessel. Observamos que o perfil parabólico ajusta-se bem aos dados do bolômetro, ao passo que o perfil gaussiano é adequado para descrever os dados obtidos com o detector de raios-X moles.

<p>This thesis aims to measure the rate of radon loss from water in a systematic way. The dependence on surface area, temperature and concentration will be investigated. The experiments were done at UWC by creating radon using radium sources and then measuring the radon concentrations inside a vacuum chamber to obtain the speed of radon escape from the water. The results are compared to a model [Cal 2002] where the radon concentration in the air and hence the transfer rate is measured using a RAD7 radon detector. Since the equations cannot be solved analytically, a numerical solution is employed. The radon transfer velocity coefficient is found to be (1.9&plusmn / 0.5)&times / 10-6m/s. This value indicates that the escape of radon should not be a problem when a sample is open to the air for a minute or two.</p>

Reproduction de : Thèse d'exercice : Médecine : Nancy 1 : 2004. / Titre provenant de l'écran-titre.

published_or_final_version / Physics / Master / Master of Philosophy

The relative contributions of bedrock geology, radiometric uranium, till permeability and surficial geology were assessed as predictors of radon in indoor air in the Halifax Regional Municipality (HRM), NS, Canada. Bedrock geology and radiometric uranium were statistically significant predictors (14.4%) of indoor radon, based on available indoor radon data. Permeability was not among the predictors, which was surprising given its importance in past studies. In a follow up field analogue study done in laboratory columns, the permeability and diffusivity, as gas transport mechanisms, were found, as suspected, to be important drivers on the concentrations of radon-222 detected. Given the variable thickness of till in the HRM (< 0.5 m to > 3 m), these experiments highlighted the significance of till thickness, composition, and permeability in predicting the radioactive radon-222 potential.

<p>This thesis aims to measure the rate of radon loss from water in a systematic way. The dependence on surface area, temperature and concentration will be investigated. The experiments were done at UWC by creating radon using radium sources and then measuring the radon concentrations inside a vacuum chamber to obtain the speed of radon escape from the water. The results are compared to a model [Cal 2002] where the radon concentration in the air and hence the transfer rate is measured using a RAD7 radon detector. Since the equations cannot be solved analytically, a numerical solution is employed. The radon transfer velocity coefficient is found to be (1.9&plusmn / 0.5)&times / 10-6m/s. This value indicates that the escape of radon should not be a problem when a sample is open to the air for a minute or two.</p>

Diss. (sammanfattning) Linköping : Univ., 2003. / Härtill 6 uppsatser.

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