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Description of bubble behavior in liquid column
Münster, Filip ; Sluše, Jan (referee) ; Rudolf, Pavel (advisor)
This bachelor’s thesis describes behavior of bubbles in liquid column. In the first part are introduced basic terms and forces which influence the motion, shape and behavior of the bubble. The second part is devoted to derivation of relations for mathematical model of the bubble motion and the model realization. In the last part the model is compared with experiment.
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Controlled generation of bubbles
Petráček, Michael ; Himr, Daniel (referee) ; Rudolf, Pavel (advisor)
This bachelor’s thesis describes behaviour of bubbles in supersaturated liquid. In the first part is described a mechanism of nucleation bubbles, their growth and motion in liquid. There are the results of experiment with a theoretical calculation compared in the second part.
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Modeling two-phase bubble flow in microfluidics
Stehlík, Martin ; Kozák, Jiří (referee) ; Rudolf, Pavel (advisor)
The goal of submitted thesis is to perform a computer simulation of bubble creation in T-channel. In the first section of the paper, the theoretical applications of microfluidic bubble, micromachines and droplet formation are described. In the second part of the text, author uses cross flowing method for simulation od bubble creation. Furthermore, several settings in computer simulation software Fluent are mentioned. In addition, the influence of velocity at the T-channel inlet on surface tension and on bubble length is presented.
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Financial Crisis in Economies with External Imbalances: A Comparative Analysis of Ireland and Spain
Semerák, Ondřej ; Váška, Jan (advisor) ; Young, Mitchell (referee)
The financial crisis of 2007-08 has had momentous consequences for most developed countries and triggered recession on the global financial markets. Consequently, economies with pre- existing deficiencies were hit in particular. In the European Union, especially two groups of member states with specific imbalances could be discerned. This thesis is intended to discuss the impacts on economies with external imbalances, where the crisis was not rooted in public finance profligacy. The main protagonists, Ireland and Spain, experienced resembling economic boom prior to the crisis, later accompanied by accumulation of foreign debt and real estate bubbles. Nonetheless, despite the strong similarities in their economic development their paths diverged after the bust, and Ireland has been given as an example for successful austerity. This thesis presents key determinative factors which differentiated Spain from Ireland in the reviving processes to discuss the hypothesis that the Irish recovery was generated solely by the implemented countermeasures and that it can therefore be considered a model for future crisis management. The objective of this thesis is to address this assertion and to evaluate its correctness using a detailed overview of structural specificities of the economies, as well as of the...
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CFD Simulation of a Sub-millimetre Rising Bubble in a Stagnant Liquid.
Crha, Jakub ; Basařová, P. ; Kašpar, O.
Hydrodynamics of the multiphase apparatus is strongly affected by fluids used in the process. One of the main quantities, which determine the hydrodynamic behaviour is the rising velocity of gaseous bubbles. This velocity can be determined easily in small scale apparatuses, but it can be much more challenging in industrial-scale devices. For that reason, mathematical modeling is used. COMSOL Multiphysics, finite element CFD solver, was used to describe the behaviour of the single bubble rising in aqueous solutions of ethanol and n-propanol. Aqueous solutions of low-carbon alcohols are extensively used in many multiphase chemical processes such as distillation, flotation and in multiphase reactors. Bubble velocities and shapes obtained from the simulation were compared to experimental and theoretical values. Two initial diameters of bubbles were used – 0.6 and 0.8 mm. Terminal velocities and shapes deformations obtained from COMSOL of 0.6 mm bubble were in an agreement with theoretical and experimental values.
Plný tet:  PDF
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Controlled generation of bubbles
Petráček, Michael ; Himr, Daniel (referee) ; Rudolf, Pavel (advisor)
This bachelor’s thesis describes behaviour of bubbles in supersaturated liquid. In the first part is described a mechanism of nucleation bubbles, their growth and motion in liquid. There are the results of experiment with a theoretical calculation compared in the second part.
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Financial Crisis in Economies with External Imbalances: A Comparative Analysis of Ireland and Spain
Semerák, Ondřej ; Váška, Jan (advisor) ; Young, Mitchell (referee)
The financial crisis of 2007-08 has had momentous consequences for most developed countries and triggered recession on the global financial markets. Consequently, economies with pre- existing deficiencies were hit in particular. In the European Union, especially two groups of member states with specific imbalances could be discerned. This thesis is intended to discuss the impacts on economies with external imbalances, where the crisis was not rooted in public finance profligacy. The main protagonists, Ireland and Spain, experienced resembling economic boom prior to the crisis, later accompanied by accumulation of foreign debt and real estate bubbles. Nonetheless, despite the strong similarities in their economic development their paths diverged after the bust, and Ireland has been given as an example for successful austerity. This thesis presents key determinative factors which differentiated Spain from Ireland in the reviving processes to discuss the hypothesis that the Irish recovery was generated solely by the implemented countermeasures and that it can therefore be considered a model for future crisis management. The objective of this thesis is to address this assertion and to evaluate its correctness using a detailed overview of structural specificities of the economies, as well as of the...
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Econometric Analysis of Bitcoin and its 2013 Bubbles
Fišer, Pavel ; Kukačka, Jiří (advisor) ; Skuhrovec, Jiří (referee)
This thesis examines Bitcoin in 2012-2015 period along with the two Bit- coin bubbles - April 2013 and November 2013 - using ARIMA, GARCH and LPPL models. First, we perform standard GARCH analysis along with GARCH rolling estimation and find that the volatility of Bitcoin differs sub- stantially over time and that this relation is best captured by GARCH(1,1) in all studied periods. We also conclude that during the November bubble the number of irrational traders entering the market was much higher than in the April bubble which probably caused greater instability on the Bit- coin market. However, based on Ljung-box test we find these results to be questionable. For that reason, we present LPPL model and study its key parameters - power law growth rate β, frequency of log oscillation ω and its scaling ratio λ - in more detail using standard methodology and "loop analysis". We find that the November bubble experiences much faster os- cillation and lower acceleration rate of power law in comparison with the April bubble. By the end we propose hypothesis that ∆λ serves as a better indicator of the upcoming bubble crash than simple scaling ratio which we concluded to be true in our analysis of the two Bitcoin bubbles. However, further examination of other financial bubbles is needed, in order to support this...
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Modeling two-phase bubble flow in microfluidics
Stehlík, Martin ; Kozák, Jiří (referee) ; Rudolf, Pavel (advisor)
The goal of submitted thesis is to perform a computer simulation of bubble creation in T-channel. In the first section of the paper, the theoretical applications of microfluidic bubble, micromachines and droplet formation are described. In the second part of the text, author uses cross flowing method for simulation od bubble creation. Furthermore, several settings in computer simulation software Fluent are mentioned. In addition, the influence of velocity at the T-channel inlet on surface tension and on bubble length is presented.
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