Thesis (M.Sc.) - Carleton University, 2005. / Includes bibliographical references (p. 138-141). Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 120-130).

Thesis (M. Sc.)--Memorial University of Newfoundland, 1998. / Bibliography: leaves 68-75.

Techn. Universiẗat, Diss., 2001--Dresden.

Orientador: Aulus Cavalieri Carciofi / Resumo: O gasto energético diário (GED) de gatos tem sido estudado há algum tempo em gatos de laboratório, com ambiente, alimentação e massa corporal controlados. O metabolismo energético destes animais pode ser dividido em quatro compartimentos: taxa metabólica basal que soma o maior GED destes animais em torno de 60%, a atividade muscular voluntária contribuindo em torno de 30%, seguido do incremento calórico e termogênese adaptativa (10%). Nota-se que a atividade muscular voluntária contribui com porção considerável do GED destes animais, não devendo ser limitada, pois interfere diretamente no gasto energético. Estudos com animais em domicílio, com número representativo de grandes populações, que apresentam rotina de vida normal com protocolo prático e eficaz, de fácil aceitação pelos proprietários para mensurar GE, composição corporal (CC) e fluxo de água (FA) no estilo de vida habitual de gatos é importante para estudos nutricionais mais precisos. Método prático e eficaz para mensuração destes parâmetros, de fácil aplicação em domicílio e que não interfira no estilo de vida e atividade física dos animais é o método da água duplamente marcada que os mensura por meio do enriquecimento e decaimento de deutério (2H) e oxigênio 18 (18O) na água corporal. O objetivo do presente trabalho foi avaliar protocolo prático de tempos de coleta de enriquecimento (2, 4, 6, 7 e 8 horas) e decaimento (2, 4, 6, 8, 10, 12, 14, 16, 18 e 20 dias), bem como os fluidos corporais alternativos saliva e u... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The energy expenditure (EE) of cats has been studied for some time in laboratory cats, with controlled environment, feeding and body mass. The energy metabolism of these animals can be divided into four compartments: basal metabolic rate that sums the highest EE of these animals around 60%, voluntary muscle activity contributing around 30%, followed by caloric increment and adaptive thermogenesis (10%). It is noted that voluntary muscle activity contributes a considerable portion of the EE of these animals, and should not be limited, as it directly interferes with energy expenditure. Studies with animals at home, with a representative number of large populations, that present normal life routine with a practical and efficient protocol, easily accepted by the owners to measure EE, body composition (BC) and water turnover (WT) in lifestyle of cats is important for more accurate nutritional studies. A practical and effective method for measuring these parameters, which is easy to apply at home and does not interfere with the animals' lifestyle and physical activity, is the double labeled water method that measures them through the enrichment and decay of deuterium (2H) and oxygen 18 ( 18O) in body water. The aim of the present study was to evaluate the practical protocol of enrichment collection times (2, 4, 6, 7 and 8 hours) and decay (2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 days ) as well as alternative body fluids saliva and urine compared to blood for assessing the concentrati... (Complete abstract click electronic access below) / Mestre

Le projet expérimental international ITER vise à tester la faisabilité de la fusion nucléaire en tant que source d'énergie. Le banc d'essai sera un tokamak où le deutérium et le tritium seront fusionnés et des ions d'hélium et des neutrons énergétiques seront produits. Une partie de l'énergie produite sera déposée dans la zone divertor. Afin de préserver le divertor en tungstène d'ITER, il est envisagé d‘injecter de l'azote au niveau du divertor afin de rayonner plus uniformément la charge d'énergie. Ce mode opérationnel soulève plusieurs questions. Tout d'abord, comment la rétention du combustible de fusion (deutérium et tritium) dans les premières parois de tokamak sera-t-elle affectée? En particulier, est-ce que l'azote implanté agira comme une barrière à la désorption pour le tritium? Deuxièmement, à quelle production d'ammoniac peut-on s‘attendre due aux processus réactifs sur les matériaux des premières parois? Cette thèse présente une étude approfondie de l'interaction du tungstène avec le deutérium et l'azote, avec l‘examen de plusieurs facteurs clés: la rétention de l'azote et du deutérium en fonction de la fluence; l'évolution dynamique de la rétention d‘atomes de deutérium après l'implantation; l'influence de l'azote pré-implanté sur la rétention de deutérium; et la détermination quantitative de l‘ammoniac produit après une implantation séquentielle d‘azote et de deutérium dans le tungstène. Une attention particulière est donnée à l'identification précise des mécanismes de piégeage pour chacune des deux espèces de gaz (azote et deutérium) dans le tungstène. / The international experimental project ITER aims to test the feasibility of nuclear fusion as an energy source. The test bed will be a tokamak reactor where deuterium and tritium will be fused and energetic helium ions and neutrons will be released. A part of the produced energy will be exhausted in the divertor area of the tokamak. In order to preserve the tungsten divertor of ITER, it is envisioned to use nitrogen injection above the divertor in order to radiate more evenly the incident power loads. This operational plan raises several issues. Firstly, how the retention of fusion fuel (deuterium and tritium) in the tokamak first walls will be affected? In particular, does the implanted nitrogen act as a desorption barrier for tritium? Secondly, how much production of ammonia can be expected from reactive processes on the first wall materials? This thesis presents an extensive study of the interaction of tungsten with deuterium and nitrogen, with several key factors being investigated: the nitrogen and deuterium retention as a function of fluence; the dynamic evolution of retained deuterium atoms after implantation; the influence of the pre-implanted nitrogen on deuterium retention; and the amounts of ammonia that are produced on tungsten after sequential implantation of nitrogen and deuterium. A special focus is directed towards identifying the exact trapping mechanisms for each of the two gas species (nitrogen and deuterium) in tungsten.

O presente trabalho estuda a produção e modificações físico-químicas do grafeno frente a tratamentos térmicos. Em uma primeira etapa, foi investigada a síntese de grafeno pela técnica de Deposição Química a partir da fase Vapor (CVD) sobre fitas de cobre. Nós variamos quatro parâmetros que influenciam no crescimento de grafeno: fluxo de metano (CH4), fluxo de hidrogênio (H2), tempo de crescimento e grau de pureza do cobre. Usando as técnicas de caracterização de espectroscopia Raman e microscopia óptica, observamos que fluxo menor de H2 e fluxo intermediários de CH4 favorecem o crescimento de grafeno de alta qualidade. Além disso, vimos que 15 minutos de crescimento de grafeno é suficiente para cobertura do substrato de cobre com grafeno. Por fim, foi visto que o maior grau de pureza do cobre permite a produção de monocamadas de grafeno mais homogêneas. Numa segunda etapa, foi realizado um estudo com objetivo de entender a interação de hidrogênio com monocamadas de grafeno. Nós usamos amostras de grafeno depositadas em filmes de SiO2 (285 nm)/Si e tratadas termicamente em atmosfera controlada de deutério (99,8%) em temperaturas entre 200 e 800 °C. Nós também investigamos a dessorção de hidrogênio do grafeno usando amostras previamente tratadas em deutério a 600 °C e depois tratadas em atmosfera controlada de nitrogênio em temperaturas entre 200 e 800 °C. Após os tratamentos, análise por reação nuclear (NRA) foi realizada para quantificar o deutério, onde nós observamos uma grande incorporação de deutério no grafeno acima de 400 °C, tendo um aumento moderado até 800 °C. Nós também observamos que a dessorção do deutério do grafeno ocorre apenas em 800 °C, embora a dessorção de deutério do óxido de silício ocorra a partir de 600°C. Espectroscopia Raman também foi realizada após cada tratamento térmico. Os resultados mostram que os defeitos na estrutura do grafeno têm um grande aumento para as etapas de maior temperatura na incorporação de deutério. Análises realizadas com Espectroscopia de Fotoelétrons Induzidos por Raios X (XPS) mostraram que a incorporação de deutério para maiores temperaturas causa o "etching" do grafeno. Por fim, caracterizações usando Espectroscopia de Absorção de Raios X (NEXAFS) mostraram que o deutério liga-se ao grafeno sem orientação preferencial. / The present work studies the production and physical-chemical modifications of the graphene under thermal annealings. In a first study, the graphene synthesis by Chemical Vapor Deposition (CVD) on copper foils was investigated. We varied four parameters that influence the growth of graphene: methane flow (CH4), hydrogen flow (H2), growth time and copper purity. Using Raman spectroscopy and optical microscopy, we observed that lower flux of H2 and intermediate flux of CH4 leads to the growth of high quality graphene. In addition, we observed that 15 minutes growth of graphene is sufficient to cover the copper substrate. A higher copper purity allows the production of homogeneous graphene monolayers. In a second step, a study was carried out to understand the interaction of hydrogen with graphene monolayers. We used graphene samples deposited on SiO2 (285 nm)/Si films and annealed in a controlled atmosphere of deuterium (99.8%) at temperatures between 200 and 800 °C. We also investigated the hydrogen desorption of graphene using samples previously treated in deuterium at 600 °C and then annealed in a controlled atmosphere of nitrogen at temperatures between 200 and 800 °C. After the annealings, nuclear reaction analysis (NRA) was performed to quantify the deuterium, where we observed a large incorporation of deuterium in graphene above 400 °C, with a moderate increase up to 800 °C. We also observed that desorption of deuterium occurs only at 800 °C, although deuterium desorption from silicon oxide occurs at 600 °C. Raman spectroscopy was also performed after each annealing. The results show that defects in the structure of graphene have a large increase for deuterium incorporation. Analyzes carried out with X-ray Photoelectron Spectroscopy (XPS) showed that the deuterium incorporation at higher temperatures leads to graphene etching. Finally, characterizations using X-ray Absorption Spectroscopy (NEXAFS) showed that deuterium binds to graphene without preferential orientation.

Magister Scientiae - MSc (Environ & Water Science) / Studies have shown that the primary origin of salinity in river flows of the Sandspruit in the Berg Catchment located in the Western Cape Province of South Africa was mainly a result of atmospheric deposition of salts. The salts are transported to rivers through surface runoff and subsurface flow (i.e. through flow and groundwater flow). The purpose of this study was to determine the contributions of subsurface and surface flows to the total flows in the Sandspruit, Berg Catchment. Three rain events were studied. Water samples for two rain events were analysed for environmental tracers ?18O, Silica or Silicon dioxide (SiO2), Calcium (Ca2+) and Magnesium (Mg2+). Tracers used for two component hydrograph separation were ?18O and SiO2. The tracers, Ca2+ and Mg2+, revealed inconsistent contributions of both subsurface flow and surface flow. Two component hydrograph separations indicated is that groundwater is the dominant contributor to flow, while surface runoff mainly contributes during the onset of the storm event. Groundwater response to precipitation input indicated that boreholes near the river have a quicker response than boreholes further away from the river. Boreholes nearer to the river also indicate higher water levels in response to precipitation, in comparison to boreholes further from the river.

Magister Scientiae - MSc (Environ & Water Science) / Studies have shown that the primary origin of salinity in river flows of the Sandspruit in the Berg Catchment located in the Western Cape Province of South Africa was mainly a result of atmospheric deposition of salts. The salts are transported to rivers through surface runoff and subsurface flow (i.e. through flow and groundwater flow). The purpose of this study was to determine the contributions of subsurface and surface flows to the total flows in the Sandspruit, Berg Catchment. Three rain events were studied. Water samples for two rain events were analysed for environmental tracers ?18O, Silica or Silicon dioxide (SiO2), Calcium (Ca2+) and Magnesium (Mg2+). Tracers used for two component hydrograph separation were ?18O and SiO2. The tracers, Ca2+ and Mg2+, revealed inconsistent contributions of both subsurface flow and surface flow. Two component hydrograph separations indicated is that groundwater is the dominant contributor to flow, while surface runoff mainly contributes during the onset of the storm event. Groundwater response to precipitation input indicated that boreholes near the river have a quicker response than boreholes further away from the river. Boreholes nearer to the river also indicate higher water levels in response to precipitation, in comparison to boreholes further from the river.

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