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On the efforts to provide a reliable source of experimental information on turbulent subcooled boiling ow, time resolved Particle Tracking Velocimetry (PTV) experiments were carried out using HFE-301 refrigerant ow through a vertical rectangular channel with one heated wall. Measurements were performed at liquid Reynolds numbers of 3309, 9929 and 16549 over a wall heat flux range of 0.0 to 64.0 kW=m2. From the PTV measurements, liquid two dimensional turbulence statistics are available, such as: instantaneous 2-D velocity fields, time-averaged axial and normal velocities, axial and normal turbulence intensities, and Reynolds stresses. The present results agree with previous works and provide new information due to the 2-D nature of the technique, for instance, this work shows that by increasing heat ux, the boiling bubbles influence on the liquid phase is portrayed as a persistent increase of axial velocity on regions close to the heater wall. This persistent increase on the axial velocity reaches a maximum value attributed to the terminal bubble velocity. These new observed phenomena must be considered for the development and improvement of two-phase ow turbulence models. To this end, an extensive error analysis was also performed with emphasis on the applicability of the PTV measurement technique on optically inhomogeneous flows. The error quantification exhibited negligible optically induced errors for the current conditions, making the data acquired in this work a vast and reliable source.

Seafloor hydrothermal systems play a key role in Earth fs energy and geochemical budgets. They also support the existence and development of complex chemosynthetic biological ecosystems that use the mineral-laden fluids as a source of energy and nutrients. This dissertation focuses on two inter-related topics: (1) heat output and geochemical fluxes at mid-ocean ridges, and (2) structural deformation of oceanic lithosphere related to subsurface serpentinization in submarine settings. The determination of heat output is important for several reasons. It provides important constraints on the physics of seafloor hydrothermal processes, on the nature of the heat sources at mid-ocean ridges, and on nutrient transport to biological ecosystems. Despite its importance, measurements of hydrothermal heat outputs are still scarce and cover less than 5% of active hydrothermal vent sites. In this work, we report development of two new devices designed to measure fluid flow velocities from the submersible at temperatures of up to 450 C and depths 5,000 m. By using these instruments on 24 Alvin dives, new measurements of hydrothermal heat output have been conducted at the Juan de Fuca Ridge, including first measurements from the High Rise and Mothra hydrothermal fields. The collected data suggest that the high-temperature heat output at the Main Endeavour Field (MEF) may be declining since the 1999 eruption. The flow measurement results, coupled with in-situ geochemical measurements, yielded the first estimates of geochemical fluxes of volatile compounds at MEF and Mothra. Our findings indicate that geochemical flux from diffuse flows may constitute approximately half of the net geochemical flux from Juan de Fuca Ridge. It has recently been recognized that serpentinization of mantle peridotites, due to its exothermic nature, may be a mechanism contributing to the heat output at mid-ocean ridges. The tectonic response of the crust to serpentinization of extensively distributed peridotites at mid-ocean ridges and subduction zones could provide a means of characterizing serpentinized regions in the oceanic lithosphere. These regions are often associated with surface topographic anomalies that may result from the volume expansion caused by the serpentinization reactions. Although there is a clear correlation between tectonics and serpentinization, the link is complex and still not understood. In this dissertation, we calculated the transformation strain and surface uplift associated with subsurface serpentinization of variously shaped ultramafic inclusions. Application of the results to explain the anomalous topographic salient at the TAG hydrothermal field (Mid-Atlantic Ridge) suggests that this feature may result from a serpentinized body beneath the footwall of a detachment fault. Because the depth of the potential serpentinized region appears to be more than 1.5 times the size of the inclusion, the uplift profile is relatively insensitive to the exact location or shape of the serpentinized domain. The rate of exothermic heat release needed to produce the serpentinized volume may contribute to the ongoing diffuse flow. Application of the results to an uplift feature associated with the Kyushu ]Palau subduction zone in the western Pacific, shows that approximately 3% transformational strain in an inclined serpentinized region of the mantle wedge near the subducted Kyushu ]Palau Ridge may result in the observed uplift on the Miyazaki Plain. Using the uplift data may help to constrain the level of the subsurface serpentinization.

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Studies of resonant magnetic perturbations (RMP) have been an active topic in the tokamak research. The RMP technique involves the use of magnetic perturbations generated by external coils installed on a tokamak device. The resonant interaction between the plasma and RMP has favorable effects on magnetohydrodynamic (MHD) stability and other plasma parameters in tokamaks. The RMP experiments are carried out in the Saskatchewan Torus-Modified (STOR-M) tokamak using (l = 2, n = 1) helical coils carrying a static current pulse. The effect of RMP on the (m = 2, n = 1) magnetic islands is examined during ohmic discharges with high MHD activities. The amplitude and frequency of (2, 1) Mirnov fluctuations are significantly reduced after application of RMP. A phase of improved plasma confinement, characterized by a reduction in the H_alpha emission level and an increase in the soft x-ray (SXR) emission, is induced after application of RMP. It is also observed using the ion Doppler spectroscopy (IDS) that RMP can strongly affect the plasma rotation in STOR-M. It is found that during the RMP pulse, the toroidal velocity of C_III impurities (located at the plasma edge) increases in the co-current direction. However, the toroidal velocities of O_V and C_VI impurities (located near the plasma core) change direction from counter-current to co-current. The reduction of the toroidal flow velocity is accompanied by a reduction of the MHD frequency. It is also found that radial profiles of ion saturation current and floating potential in the edge region can be modified by RMP. An increase in the pedestal plasma density and a more negative electric field are observed at the plasma edge region during the RMP pulse. An internal probe array is assembled and installed in STOR-M to study the RMP penetration and the plasma response to RMP.

Orientadores: Pedro Sérgio Fadini, José Roberto Guimarães / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-16T04:17:25Z (GMT). No. of bitstreams: 1 Silva_LeonardoAugustoSilvestre_M.pdf: 5806444 bytes, checksum: 66a71a65fd0f1a54aff06733e84a328e (MD5) Previous issue date: 2006 / Resumo: Neste trabalho, o objetivo principal foi a construção e otimização de câmaras visando a quantificação dos fluxos de mercúrio dissolvido gasoso (MDG), na interface água / atmosfera em lagos da Bacia Hidrográfica do Rio Negro - AM. Foram realizados trabalhos de campo utilizando-se câmaras construídas em acrílico incolor nos quais foram determinadas as concentrações de mercúrio na atmosfera externa e interna da câmara. O ar foi bombeado através de colunas preenchidas com areia de quartzo recoberta com ouro, capazes de pré-concentrar o MDG por amalgamação. A quantificação do mercúrio foi realizada empregando-se a técnica de Espectrometria de Fluorescência Atômica do Vapor Frio (CVAFS), em um equipamento operando embarcado. Em campanha realizada no mês de Janeiro de 2003, os fluxos de MDG registrados no Lago Araca (águas brancas) foram, em pmol m-2 h-1: -20,68; + 8,16 e - 0,54 em períodos sem incidência de luz, e + 29,54 ; + 32,72 em períodos iluminados. Já no Lago Iara (águas negras), os valores encontrados para MDG em períodos sem incidência de luz foram: + 28,77; + 19,00 ; + 22,35, assim como + 5,39 e - 4,85 em períodos iluminados. Os resultados sugerem que os fluxos de MDG nos lagos da Bacia do Rio Negro seguem a tendência de serem invasivos para períodos não iluminados e evasivos para períodos iluminados em águas brancas, mas evasivos para períodos não iluminados e invasivos para períodos iluminados em águas negras / Abstract: The scope of this work was the construction and optimization of fluxes chambers for the determination of dissolved gaseous mercury (DGM) in the water atmosphere interface, in lakes belonging to the Negro River basin - AM. Field work was carried out using a plexiglass flux chambers for the determination of inner and outer atmospheric gaseous mercury. The air was pumped through quartz gold-sand columns, preconcentrating the DGM by amalgamation. The mercury quantification was carried out by Cold Vapor Atomic Fluorescence Spectrometry (CVAFS), using equipment on boat. Inthe sampling period of January 2003, the DGM fluxes measured in Araca Lake (white waters) were -20.68, + 8.16 and - 0.54 pmol m-2 h-1, during a period without light incidence, and + 29.54, + 32.72 under light incidence. In the Iara Lake (black waters), the DGM fluxes were + 28.77, 19.00 and 22.35 without light incidence, and + 5.39, - 4.85 in light periods. The results suggest that DGM fluxes in white water lakes show na invasive behaviour in no light periods, as well as an evasive behaviour in light periods. However, the behaviour of DGM fluxes is opposite in black waters / Mestrado / Saneamento e Ambiente / Mestre em Engenharia Civil

Orientador: Fábio Hüsemann Menezes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-16T07:54:40Z (GMT). No. of bitstreams: 1 Medeiros_CharlesAngottiFurtadode_D.pdf: 4155361 bytes, checksum: a61d12a8785ffe83230f77cc5e0b8fde (MD5) Previous issue date: 2010 / Resumo: Objetivo: Medir o volume de fluxo arterial com mapeamento duplex, calcular a relação do volume de fluxo fêmoro/axilar e discutir a sua utilidade como um novo índice no significado hemodinâmico de uma lesão obstrutiva no segmento aorto-ilíaco. Metodologia: Diversas medidas de volume de fluxo foram obtidas consecutivamente com mapeamento duplex em artérias femorais comuns e axilares de voluntários sadios sem sinais de aterosclerose e de pacientes com diagnóstico comprovado de doença obstrutiva no segmento aorto-ilíaco por meio da medida de pressão segmentar. Posteriormente, o grupo dos pacientes foi submetido à avaliação complementar com segundo exame confirmatório. Resultados: No total, foram executadas 635 medidas de volume de fluxo em dez voluntários sadios e em oito pacientes com estenose severa ou oclusão de artéria ilíaca, sendo dois destes com doença bilateral. Quando se comparou os sujeitos normais e os pacientes com estenose severa ou oclusão de artéria ilíaca houve diferença significativa estatística entre estes dois grupos (p < 0.01 Mann-Whitney). Resultado semelhante foi encontrado na comparação dos membros doentes dos pacientes com seus próprios membros contralaterais normais (p < 0.05 Wilcoxon). A medida do volume de fluxo somente durante a fase sistólica mostrou ser um parâmetro muito mais sensível para diferenciar membros normais de membros alterados. Além disso, ficou demonstrado boa relação entre o índice de pressão de coxa proximal e o índice de fluxo sistólico fêmoro/axilar no grupo dos pacientes com estenose severa ou oclusão de artéria ilíaca (p < 0.01 Correlação de Spearman). Conclusão: O índice que relaciona o volume de fluxo arterial fêmoro/axilar é confiável na avaliação do significado hemodinâmico da doença obstrutiva no segmento aorto-ilíaca e, poderá ser utilizado como uma ferramenta útil durante o segmento destes doentes / Abstract: Objective: To measure the arterial volume flow with duplex scan, calculate femoral/axillary volume flow ratio and discuss its applicability as a new index for the hemodynamic significance of an aorto-iliac occlusive lesion. Methods: Several measures of volume flow were obtained consecutively with duplex scan in both common femoral and axillary arteries of healthy volunteers with no signs of atherosclerosis and patients with documented evidence of occlusive aorto-iliac disease with segmental pressure measurement. Then patients group was sent to complimentary evaluation with a second confirmatory exam. Results: There were a total of 635 measures of volume flow performed in ten healthy volunteers and eight patients with iliac severe stenoses or occlusion, two of then with bilateral disease. When comparing normal subjects and patients with iliac severe stenoses or occlusion there was statistical significant difference between these two groups (p < 0.01 Mann-Whitney). Similar result was found when comparing patient diseased limbs with their own contra-lateral normal side (p < 0.05 Wilcoxon). And measuring the volume flow only during the systolic phase was a much more sensitive parameter for differentiate normal from diseased. Besides that there was found a good correlation between proximal thigh pressure index and femoral/axillary systolic flow ratio in the patients group (p < 0.01 Spearman Correlation). Conclusion: The femoral/axillary volume flow ratio is useful in assessing the hemodynamic significance of aorto-iliac disease and systolic femoral/axillary ratio may also be useful as a follow-up tool / Doutorado / Doutor em Cirurgia

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