The usage of smartphones has been increasing with surprising speed. These smartphones are popular for delivery of video content. The main drawbacks of these smartphones are battery life and video freezing. Despite, while streaming a video it consumes large of amount of power affecting QoE. So, in this case we considered streaming a video from server to mobile client involving ONOFF characteristics. While streaming, there exists some transition delay while switching the power states and the effect of these transition delays might affect instantaneous power consumption of the smartphone. Henceforth, this thesis aims to determine the effect on instantaneous power consumption from distributed state durations and transitions in exponential fluid flow model, for a streamed video. Power measurements along with ON and OFF times were measured with the help of a benchmark tool, Monsoon Power Monitor tool. VLQoE tool, a video streaming tool was used to present a two state model based on the inter-picture time, for the HTTP-based video streaming. Experiments were executed in a closed enclosure setup using a black-box to avoid external obstacles that might possibly affect the power consumption metrics. Considering these measurements, the effect on instantaneous power consumption stemming from the exponentially distributed state durations and transitions in the corresponding fluid flow model can be determined and modelled.

This work focuses on improving video transmission quality over a mobile link. More specifically, the impact of buffering and link outages on the freeze probability of transmitted videos is studied. It introduces a new fluid flow model that provides an approximation of the freeze probability in the presence of play-out hysteresis. The proposed model is used to study the impact of two streaming buffer sizes over different possible combinations of outage parameters (data channel on/off times). The outcome of this thesis shows that outage parameters play a dominant role in freezing of streaming video content, and that an increase in these parameters cannot be easily compensated for by an increase in the size of the receiving buffer. Generally, in most cases when there is a variation in outage parameters, an increased buffer size has a negative impact on the freeze probability. To lower the probability of freeze during video playback over a weak mobile link, it is better to sacrifice resolution just to keep the video content playing. Similarly, shifting focus from off to on times brings better results than increasing buffer size.

A principle concern for engineered CO2 storage is long-term security. Surface leakage (‘seepage’) of injected CO2 to the surface is economically and environmentally undesirable. Italy is a region of intense natural CO2 degassing; 308 CO2 seeps are catalogued which exhibit different surface characteristics, and a number CO2 rich reservoirs were discovered when drilling for hydrocarbons. These seeps and reservoirs provide excellent natural analogues for seeps that might arise from breached carbon stores. This thesis explores the geological controls on the crustal plumbing of CO2 fluids to model the processes governing CO2 seep locations and distribution, and characteristics; and their consequences on human health risk. Risk of human death from accidental CO2 poisoning at all seep types is low (10-8 yr-1) and several factors influence risk of human mortality. Seeps distribute on two spatial scales; on a local scale (<5 km) seeps are clustered and aligned with subsidiary geologic structures, while on large scales seep clusters are discrete, and align with regional structures. Within clusters, seep locations are influenced by fault maturity, the presence of lithological boundaries and seep manifestation, which is determined by the flow properties of the outcropping lithology and local topography. Sealing and seeping CO2 reservoirs are identified, and their geological characteristics compared. Italian reservoirs successfully retain large CO2 columns at a range of reservoir conditions. Reservoirs which have hydrostatic pressure conditions in the overburden, determined from well logs, are located close to surface CO2 seeps and recent extensional faults. Where there is significant overpressure above hydrostatic in the overburden, there are no seeps present above the reservoir structure. Overpressure of reservoir fluids may enhance fluid flow rates but is not a necessary condition for CO₂ leakage. Geothermal conditions influences the style of leakage at depths and towards the surface. Total CO2 degassing from dry Italian CO2 seeps is 3.5 ± 0.5 Mt(CO2)yr-1. It would take thousands of years for the effectiveness of a commercial scale store to be significantly reduced if it leaks to form a single seep with the mean flux rates modeled in Italy. If a seep cluster develops, the storage effectiveness will reduce more rapidly, and could negate engineered CO₂ storage as a climate mitigation strategy. The research presented in this thesis contributes to a body of knowledge which directly informs site selection procedure for carbon storage and maximise the long term storage potential for CCS. Thorough scientific understanding of the geological processes governing fluid escape is crucial to assure the scientific, political and public communities that safe, long-term carbon storage can be realised as an effective climate mitigation technology.

A teoria da percolação tem se revelado muito útil no tratamento de inúmeros fenômenos da natureza. Devido a sua grande versatilidade, esta teoria é objeto de intensa pesquisa. Aqui, propomos novas formas de percolação e as estudamos através de simulações numéricas. Na primeira parte de nosso trabalho, investigamos a estrutura dos aglomerados gerados pelo modelo de percolação por invasão múltipla. Estimamos os valores das dimensões fractais do esqueleto, do esqueleto elástico, dos pontos de estrangulamento e dos menores caminhos, como função dos parâmetros do modelo. Por ter uma estrutura geométrica bastante estabilizada, o modelo otimizado pode vir a ser muito útil no tratamento de problemas com diluição da mecânica estatística. O modelo de percolação atenuada foi concebido para permitir que, durante o processo de invasão, os poros grandes possam também ser ocupados. Esta ocupação ocorre com uma probabilidade que diminui quando o tamanho do poro aumenta.Estimamos cuidadosamente os limiares de percolação e construímos os diagramas de fase correspondentes. Verificamos que os limiares de percolação de nosso modelo não satisfazem a conjectura de Galam e Mauger. Estudamos o efeito da inércia em fluidos escoando através de meios porosos incorporando uma caminhada de N passos ao modelo de percolação por invasão. A magnitude da inércia é proporcional ao parâmetro N, que representa o número de poros seqüencialmente invadidos após a ruptura do perímetro, em cada etapa do processo. Investigamos este modelo em duas e três dimensões. Verificamos que no caso bidimensional, as caminhadas de N passos são facilmente bloqueadas o que leva ao surgimento de um limite superior para o número de passos efetivamente realizados. Nossas estimativas das dimensões fractais dos aglomerados (como função do parâmetro N), indicam que este modelo pertence a uma classe de universalidade diferente daquela da percolação por invasão ordinária. Propomos um modelo de percolação para tratar um processo de solidificação de dois fluidos imiscíveis na presença de impurezas móveis. O movimento das impurezas ocorre devido a uma interação repulsiva de curto alcance observada experimentalmente por Ulhmann, Chalmers e Jackson (UCJ). Dependendo das concentrações de fluidos e impurezas, pode haver a formação de uma fase sólida que percola todo o sistema. Construímos o diagrama de fases deste modelo no espaço das concentrações e calculamos seus expoentes críticos. Nossos resultados indicam que o modelo pertence à mesma classe de universalidade que a percolação ordinária. Finalmente, estudamos um processo de percolação por invasão na presença de impurezas que se movem segundo o mecanismo UCJ. Encontramos um valor crítico para a concentração de impurezas, acima do qual não mais existe percolação. O perfil de aceitação aproxima-se de uma função de Heavyside, com o ponto de descontinuidade dependendo da concentração de impurezas. / Percolation theory provides a quantitative and conceptual model for the understanding of many natural phenomena. Here, we present new kinds of percolation and study them using Monte Carlo simulation techniques. We start studying the cluster, the backbone and the elastic backbone structures of the multiple invasion percolation for both the perimeter and the optimized versions. The behavior of the mass, the number of cutting sites and loops are investigated and their corresponding scaling exponents are estimated. By construction, the mass of the optimized model scales exactly with the gyration radius of the cluster - we verify that this also happens with the backbone. Our simulation shows that the red sites almost disappear, indicating that the cluster has achieved a high degree of connectivity. We propose a new kind of invasion percolation, which permits that, besides small pores, large pores being also occupied. In our model, the occupation probability of a pore diminishes with the pore\'s size. We estimate their corresponding percolation thresholds and show that they do not satisfy the Galam and Mauger conjecture. In order to take into account the inertia of the invader fluid, a new kind of invasion percolation is introduced. In this model, which we named N-steps invasion percolation, the inertia forces are controlled by the number N of pores (or steps) invaded after the perimeter rupture. The new model belongs to a different class of universality and has its fractal dimension depending on N. A blocking phenomenon takes place in two dimensions. It imposes an upper bound value on N. For pores sizes larger than the critical threshold, the acceptance profile exhibits a permanent tail. We also introduce a model for the solidification process of two immiscible fluids interacting repulsively with mobile impurities on a two dimensional square lattice. In the space of the fluids and impurities concentrations the phase diagram exhibits a critical curve separating a percolating from a non-percolating phase. Estimated values for the fractal dimension and the exponent ? of the order parameter, reveal that the critical exponents do not vary along this curve, i.e., they are independent of the impurities concentration. The universality class we find is that of the ordinary percolation. Finally, based on the main ideas of the dynamic epidemic and invasion percolation models, we propose a model to describe the cleaning process of a dirty porous medium by fluid injection. An analysis of the acceptance profiles strongly indicates that this model is a kind of self-organized system.

Generalizamos o modelo de percolação por invasão de maneira que vários sítios possam ser simultaneamente invadidos. Propomos dois tipos de generalização: na primeira, o fluxo de fluido invasor e controlado através do perímetro do aglomerado, enquanto que na segunda modificação, o crescimento e governado pela relação de escala entre a massa e o raio de giração dos aglomerados. Estudamos cuidadosamente tanto o perfil de aceitação quanto as dimensões fractais (\'D IND.F\') dos aglomerados assim crescidos. No modelo baseado nas relações de escala, \'D IND.F\' pode ser tratado como um mero parâmetro real que pode assumir qualquer valor no intervalo (0, ?). Nos intervalos (0, \'91 SOB.48\') e (2, ?), o sistema e frustrado. Para \'D IND.F\' > 2, o modelo exibe um fenômeno interessante: em algumas etapas ocorrem explosões no crescimento da massa dos aglomerados (bursts). Na região [\'91 SOB.48\',2], os aglomerados obedecem exatamente e em qualquer escala a relação M ~ RgDF entre a massa m e o raio de giração \'RG\'. Acreditamos que estes fractais cuja estrutura completamente e estabilizada possam ser muito úteis no tratamento de problemas de diluição da mecânica estatística. / We generalize the standard site invasion percolation model to permit simultaneous invasion of several sites. We propose two kinds of generalizations: one in which the invasion flux is controlled by the perimeter size and another where the scaling properties command the growth process. The acceptance profile as well as the fractal dimension \'D IND.F\' are carefully studied. In the model based on scaling relation, \'D IND.F\' can be treated as a mere real parameter in the range (0, ?). In the intervals (0, \'91 SOB.48\') and (2, ?) the system is frustrated. For \'D IND.F\' > 2 the model exhibits also an interesting burst phenomenon that is explained in the text. In the region [\'91 SOB.48\',2], the clusters obey exactly and in any scale the relation M ~ RgDF between the mass M and gyration radius Rg. These stable random fractals may be very useful in the study of dilute systems.

An integrated field , microstructure, fracture statistic , geochemistry , and laboratory permeability study of the East Fork and White Rock fault zones , of similar age and tectonic regime but different structural level and hydrogeologic history , provides detailed information about the internal deformation and fluid flow processes in fault zones . The primary conclusions of this research are: 1) Fault zones can be separated into subzones of protolith, damaged zone , and gouge /cataclasite , based on physical morphology and permeability structure . At deep structural levels, gouge/cataclasite zones are more evolved (thicker with increased grain size reduction) due to strain localization , higher pressure and temperature, and fluid/rock interaction ; 2) Deformation mechanisms evolved from primarily brittle fracturing and faulting in the damaged zone to extreme, fluid-enhanced chemical breakdown and cataclasis which localized strain in the fault core. Deformation in the deep-level-fault core may be a combination of frictional and quasiplastic mechanisms, and is largely controlled by extremely fine-grained clays, zeolites , and other phyllosilicates that may have acted as a thermally pressurized, fluid-saturated lubricant; 3) Permeability in fault zones was temporally heterogeneous and anisotropic (permeability of damaged zone>protolith>gouge /cataclasite, permeability along fault> permeability across fault); 4) Volume loss was concentrated in the fault cores and was negligible at intermediate structural levels and high at deep structural levels in the semi-brittle to brittle regime ; 5) Fluid flow and solute transport were concentrated upwards and subparallel to the fault in the damaged zone ; 6) Faults at both the local and regional scale acted as fluid flow conduit/barrier systems depending upon the evolutionary stage and interval in the seismic cycle ; 7) Fluid/rock volume ratios , fluid flux , and fluid/rock volume ratios over time ranged from ⋍ 103 to 104, 10-6 ms-1 to 10-9 ms-1, and 0.05 L/m3 rock•yr to 0.50 L/m3 rock•yr, respectively, suggesting that enormous quantities of fluids passed through the fault zones; 8) Box counting fractal analyses of fault zone fractures showed that fracture spatial and density distribution is scale-invariant at the separate scales of outcrop , hand-sample , and thin section, but self-affine from outcrop to thin-section scale; 9) Linear fractal analysis depicts clustering and density distribution as a function of orientation, and may be a quick, robust method of estimating two-dimensional fracture permeability; and 10) Fractal analysis of fractures is not a comprehensive statistical method, but can be used as another supplemental statistical parameter.

In order to understand water quality in the coastal ocean and its effects on human health, the necessity arises to locate the sources of contaminants and track their transport throughout the ocean. Dynamical systems methods are applied to the study of transport of enterococci as an indicator of microbial concentration in the vicinity of Hobie Beach, an urban, subtropical beach in Miami, FL that is used for recreation and bathing on a daily basis. Previous studies on water quality have shown that Hobie Beach has high microbial levels despite having no known point source. To investigate the cause of these high microbial levels, a combination of measured surface drifter trajectories and numerically simulated flows in the vicinity of Hobie Beach is used. The numerically simulated flows are used to identify Lagrangian Coherent Structures (LCSs), which provide a template for transport in the study area. Surface drifter trajectories are shown to be consistent with the simulated flows and the LCS structure. LCSs are then used to explain the persistent water contamination and unusually high concentrations of microbes in the water off of this beach as compared with its neighboring beaches. From the drifter simulations, as well as field experiments, one can see that passive tracers are trapped in the area along the coastline by LCS. The Lagrangian circulation of Hobie Beach, influenced primarily by tide and land geometry causes a high retention rate of water near the shore, and can be used to explain the elevated levels of enterococci in the water.

Osteocytes are believed to be the mechanosensory cells that detect and respond to mechanical loading. Physiological loading by oscillatory fluid flow (OFF) activates osteocytes to increase intracellular calcium concentration and release prostaglandin E2 (PGE2). Osteocytes are also sensitive to chemical stimulations such as serotonin, which can also increase PGE2 release. However, it is unclear whether mechanical stimulation can influence osteocyte sensitivity towards serotonin. In this thesis, MLO-Y4 osteocyte-like cells were subjected to serotonin with or without precondition by OFF, the responses of intracellular calcium and PGE2 release were measured. Serotonin increased intracellular calcium and PGE2 release in osteocytes. The effects were significantly reduced by OFF precondition, suggesting mechanical precondition by OFF can reduce osteocyte sensitivity towards serotonin. In terms of mechanisms, OFF- and serotonin-induced calcium responses depended on intra- and extracellular calcium stores. ATP was found to partially mediate OFF modulation of serotonin-induced PGE2 release but not calcium.

Osteocytes are believed to be the mechanosensory cells that detect and respond to mechanical loading. Physiological loading by oscillatory fluid flow (OFF) activates osteocytes to increase intracellular calcium concentration and release prostaglandin E2 (PGE2). Osteocytes are also sensitive to chemical stimulations such as serotonin, which can also increase PGE2 release. However, it is unclear whether mechanical stimulation can influence osteocyte sensitivity towards serotonin. In this thesis, MLO-Y4 osteocyte-like cells were subjected to serotonin with or without precondition by OFF, the responses of intracellular calcium and PGE2 release were measured. Serotonin increased intracellular calcium and PGE2 release in osteocytes. The effects were significantly reduced by OFF precondition, suggesting mechanical precondition by OFF can reduce osteocyte sensitivity towards serotonin. In terms of mechanisms, OFF- and serotonin-induced calcium responses depended on intra- and extracellular calcium stores. ATP was found to partially mediate OFF modulation of serotonin-induced PGE2 release but not calcium.

Microfluidic chips have drawn great attention and interest due to their broad applications in chemical, biological and biomedical fields. These kinds of miniaturized devices offer many advantages over the traditional analysis instruments, such as reduced cost, shortened time, increased throughput, improved integration/automation/portability, etc. However, the concept of integrating multiple labs on a single chip to perform micro total analysis hasn’t been realized yet because of the lack of fundamental knowledge and systematic design of each component, especially for some particular applications. A thorough understanding and grasp of the basic physical phenomenon is the theoretical basis to develop functional devices to utilize them. In this study, we intend to investigate the electrokinetic fluid flow and coherent species transport processes in microchannels, and then try to effectively control them for designing related lab-on-a-chip devices. Rather than expensive experiments, numerical studies are performed to simulate the different processes involved in various electrokinetic chip applications. In the theoretical models, applied potential field, flow field and species concentration field are considered and corresponding governing equations with initial/boundary conditions are numerically solved by computational fluid dynamics techniques. The flow field is obtained by the developed SIMPLE algorithm and a slip-wall velocity boundary condition is applied in simulating electroosmotic flow. Grid independence tests and convergence studies are performed to ensure economic computation with adequate accuracy and stability. For every application with typical channel layout, parametric studies are performed to investigate different effects through the controlling parameters linked to them. For surface patterning or microfabrication using laminar flows, various operational parameters are investigated to explore the optimized configurations for multi-stream flow and mass transport control in cross-linked microchannels. Through a series of numerical simulations, it is found that applied potentials, electroosmotic mobilities of solutions and channel dimensions have significant effects on the flow and mass transport after converging in the intersection of channel network. Diffusion coefficient has less influence than the other parameters due to the presence of high Peclet number for such applications. For the microwashing with two different electrolyte solutions, a three-dimensional model is numerically solved to reveal the flow structure change. In a straight microchannel with a rectangle cross section, KCl solution and LaCl3 solution are mainly employed for tests. Displacement processes between two solutions in both orders are tested and analyzed. The observed flow structures such as back flow in channel center and distortion of plug-like velocity profile are noticed and discussed. The distortion of the flow field results from the induced pressure gradient, which is due to the non-uniformity of electroosmotic mobilities and electrical conductivities of two replaced solutions. The bigger difference two solutions have in chemical properties, the stronger effects on flow they have. Effect of applied potential field strength is also studied and the approximate linear influences are concluded. Finally, the unsteady on-chip sample injection and separation processes involved in microchip capillary electrophoresis are studied. Species’ electrophoretic migration effect is included and the theoretical model is non-dimensionalized in a unique manner with the key fundamental parameters: the Re Sci , species’ non-dimensional electrophoretic mobility and applied potentials. The species transport characteristics are revealed numerically and well understood for future effective control and innovative chip design. Species front movement during injection and sample plug development in separation are examined with diffusion effect; results include concentration profiles and contour plots over a range of injection and separation time. The influence of i Re Sc which characterizes the relative role of convection versus diffusion is examined over the commonly encountered range and the diffusion effect is found to have an essentially negligible effect. Through three species, the electrophoretic mobilities difference is demonstrated to be the reason for separation. Real-time monitoring of different species’ movements is performed for injection guidance.