927 resultados para Taylor bubble
Resumo:
This thesis is concerned with Maine de Biran’s and Samuel Taylor Coleridge’s conceptions of will, and the way in which both thinkers’ posterities have been affected by the central role of these very conceptions in their respective bodies of thought. The research question that animates this work can therefore be divided into two main parts, one of which deals with will, while the other deals with its effects on posterity. In the first pages of the Introduction, I make the case for a comparison between two philosophers, and show how this comparison can bring one closer to truth, understood not in objective, but in subjective terms. I then justify my choice by underlining that, in spite of their many differences, Maine de Biran and Samuel Taylor Coleridge followed comparable paths, intellectually and spiritually, and came to similar conclusions concerning the essential activity of the human mind. Finally, I ask whether it is possible that this very focus on the human will may have contributed to the state of both thinkers’ works and of the reception of those works. This prologue is followed by five parts. In the first part, the similarities and differences between the two thinkers are explored further. In the second part, the connections between philosophy and singularity are examined, in order to show the ambivalence of the will as a foundation for truth. The third part is dedicated to the traditional division between subject and object in psychology, and its relevance in history and in moral philosophy. The fourth part tackles the complexity of the question of influence, with respect to both Maine de Biran’s and Coleridge’s cases, both thinkers being indebted to many philosophers of all times and places, and having to rely heavily on others for the publication, or the interpretation of their own works. The fifth part is concerned with the different aspects of the faculty of will, and primarily its relationship with interiority, as incommensurability, and actual, conditioned existence in a certain historical and spatial context. It ends with a return to the question of will and posterity and an announcement of what will be covered in the main body of the thesis. The main body is divided into three parts:‘L’émancipation’, ‘L’affirmation, and ‘La projection’. The first part is devoted to the way Maine de Biran and Samuel Taylor Coleridge extricated themselves from one epistemological paradigm to contribute to the foundation of another. It is divided in four chapters. The first chapter deals with the aforementioned change of paradigm, as corresponding to the emergence of two separate but associated movements, Romanticism and what the French philosopher refers to as ‘The Age of History’. The second chapter concerns the movement that preceded them, i.e. the Enlightenment, its main features according to both of our thinkers, and the two epistemological models that prevailed under it and influenced them heavily in their early years: Sensationism (Maine de Biran) and Associationism (Coleridge). The third chapter is about the probable influence of Immanuel Kant and his followers on Maine de Biran and Coleridge, and the various facts that allow us to claim originality for both thinkers’ works. In the fourth chapter, I contrast Maine de Biran and Coleridge with other movements and thinkers of their time, showing that, contrary to their respective thoughts, Maine de Biran and Coleridge could not but break free from the then prevailing systematic approach to truth. The second part of the thesis is concerned with the first part of its research question, namely, Maine de Biran’s and Coleridge’s conceptions of the will. It is divided into four chapters. The first chapter is a reflection on the will as a paradox: on the one hand, the will cannot be caused by any other phenomenon, or it is no longer a will; but it cannot be left purely undetermined, as if it is, it is then not different from chance. It thus needs, in order to be, to be contradictorily already moral. The second chapter is a comparison between Maine de Biran’s and Coleridge’s accounts of the origin of the will, where it is found that the French philosopher only observes that he has a will, whereas the English philosopher postulates the existence of this will. The comparison between Maine de Biran’s and Coleridge’s conceptions of the will is pursued in the third chapter, which tackles the question of the coincidence between the will and the self, in both thinkers’ works. It ends with the fourth chapter, which deals with the question of the relationship between the will and what is other to it, i.e. bodily sensations, passions and desires. The third part of the thesis focuses on the second part of its research question, namely the posterity of Maine de Biran’s and Coleridge’s works. It is divided into four chapters. The first chapter constitutes a continuation of the last chapter of the preceding part, in that that it deals with Maine de Biran’s and Coleridge’s relations to the ‘other’, and particularly their potential and actual audience, and with the way these relations may have affected their writing and publishing practices. The second chapter is a survey of both thinkers’ general reception, where it is found that, while Maine de Biran has been claimed by two important movements of thoughts as their initiator, Coleridge has been neglected by the only real movement he could have, or may indeed have pioneered. The third chapter is more directly concerned with the posterities of Maine de Biran’s and Coleridge’s conceptions of will, and attempts to show that the approach to, and the meaning of the will have evolved throughout the nineteenth century, and in the French Spiritualist and the British Idealist movements, from an essentially personal one to a more impersonal one. The fourth chapter is a partial conclusion, whose aim is to give a precise idea of where Maine de Biran and Coleridge stand, in relation to their century and to the philosophical movements and matters we are concerned with. The conclusion is a recapitulation of what has been found, with a particular emphasis on the dialogue initiated between Maine de Biran and Coleridge on the will, and the relation between will and posterity. It suggests that both thinkers have to pay the price of a problematic reception for the individuality that pervades their respective works, and goes further in suggesting that s/he who chooses to found his individuality on the will is bound to feel this incompleteness in his/her own personal life more acutely than s/he who does not. It ends with a reflection on fixedness and movement, as the two antagonistic states that the theoretician of the will paradoxically aspires to.
An ultrasonic instrumentation system for the study of vapour bubble formation and collapse in sodium
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Investigations into the modelling techniques that depict the transport of discrete phases (gas bubbles or solid particles) and model biochemical reactions in a bubble column reactor are discussed here. The mixture model was used to calculate gas-liquid, solid-liquid and gasliquid-solid interactions. Multiphase flow is a difficult phenomenon to capture, particularly in bubble columns where the major driving force is caused by the injection of gas bubbles. The gas bubbles cause a large density difference to occur that results in transient multi-dimensional fluid motion. Standard design procedures do not account for the transient motion, due to the simplifying assumptions of steady plug flow. Computational fluid dynamics (CFD) can assist in expanding the understanding of complex flows in bubble columns by characterising the flow phenomena for many geometrical configurations. Therefore, CFD has a role in the education of chemical and biochemical engineers, providing the examples of flow phenomena that many engineers may not experience, even through experimentation. The performance of the mixture model was investigated for three domains (plane, rectangular and cylindrical) and three flow models (laminar, k-e turbulence and the Reynolds stresses). mThis investigation raised many questions about how gas-liquid interactions are captured numerically. To answer some of these questions the analogy between thermal convection in a cavity and gas-liquid flow in bubble columns was invoked. This involved modelling the buoyant motion of air in a narrow cavity for a number of turbulence schemes. The difference in density was caused by a temperature gradient that acted across the width of the cavity. Multiple vortices were obtained when the Reynolds stresses were utilised with the addition of a basic flow profile after each time step. To implement the three-phase models an alternative mixture model was developed and compared against a commercially available mixture model for three turbulence schemes. The scheme where just the Reynolds stresses model was employed, predicted the transient motion of the fluids quite well for both mixture models. Solid-liquid and then alternative formulations of gas-liquid-solid model were compared against one another. The alternative form of the mixture model was found to perform particularly well for both gas and solid phase transport when calculating two and three-phase flow. The improvement in the solutions obtained was a result of the inclusion of the Reynolds stresses model and differences in the mixture models employed. The differences between the alternative mixture models were found in the volume fraction equation (flux and deviatoric stress tensor terms) and the viscosity formulation for the mixture phase.
Resumo:
The simulation of two-phase flow for an experimental airlift reactor (32-l volume) using commercially available software from Fluent Incorporated is presented here (http://www.fluent.co.uk). Data from the simulation is compared with the experimental data obtained by the tracking of a magnetic particle and analysis of the pressure drop to determine the gas hold-up. Comparisons between vertical velocity and gas hold-up were made for a series of experiments where the superficial gas velocity in the riser was adjusted between 0.01 and 0.075 m s-1. © 2003 Elsevier B.V. All rights reserved.
Resumo:
An alternative approach to the modelling of solid-liquid and gas-liquid-solid flows for a 5:1 height to width aspect ratio bubble column is presented here. A modified transport equation for the volume fraction of a dispersed phase has been developed for the investigation of turbulent buoyancy driven flows (Chem. Eng. Proc., in press). In this study, a modified transport equation has been employed for discrete phase motion considering both solid-liquid and gas-liquid-solid flows. The modelling of the three-phase flow in a bubble column was achieved in the following case: injecting a slug of solid particles into the column for 10 s at a velocity of 0.1 m s-1 and then the gas phase flow was initiated with a superficial gas velocity of 0.02 cm s-1. © 2003 Elsevier B.V. All rights reserved.
Resumo:
Using the analogy between lateral convection of heat and the two-phase flow in bubble columns, alternative turbulence modelling methods were analysed. The k-ε turbulence and Reynolds stress models were used to predict the buoyant motion of fluids where a density difference arises due to the introduction of heat or a discrete phase. A large height to width aspect ratio cavity was employed in the transport of heat and it was shown that the Reynolds stress model with the use of velocity profiles including the laminar flow solution resulted in turbulent vortices developing. The turbulence models were then applied to the simulation of gas-liquid flow for a 5:1 height to width aspect ratio bubble column. In the case of a gas superficial velocity of 0.02 m s-1 it was determined that employing the Reynolds stress model yielded the most realistic simulation results. © 2003 Elsevier B.V. All rights reserved.
Resumo:
Basic hydrodynamic parameters of an airlift reactor with internal loop were estimated experimentally and simulated using commercially available CFD software from Fluent. Circulation velocity in a 32-dm(3)-airlift reactor was measured using the magnetic tracer method, meanwhile the gas hold-up was obtained by analysis of the pressure drop using the method of inverted U-tube manometers. Comparison of simulated (in two and three dimensions) and experimental data was performed at different superficial gas velocities in the riser.
Resumo:
The simulation of two-phase flow in bubble columns using commercially available software fromFluent Incorporated is presented here. Data from a bubble column with a ratio of height to thecolumn diameter of 5 : 1 are compared with simulations and experimental results for time-averaged velocity and Reynolds stress proles are used to validate transient, two-dimensional simulations.The models are based on multiphase biological reactors with applications in the food industry. An example case of the mass transfer of oxygen through the liquid phase is also presented.
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2000 Mathematics Subject Classification: 47A10, 47A13.
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A 2007 óta kibontakozó válság újból divatba hozta a korai buborékok és válságok témáját. A jelenlegi válság nyomán újraéledtek a makroökónómiai viták, kétségessé vált a "nagy mérséklődés" és az újklasszikus szintézis érvényessége. Az 1634-1637 közötti holland tulipánmánia - mint az első buborék - sokféle értelmezése ismeretes: a tömeghisztéria kitörésétől a hatékony pénzügyi piacok korai példáján át a kulturális sokkig. Áttekintve ezeket, a cikk visszavezeti a tulipánmánia közismert anekdotikus leírásait az eredeti forrásokig, és megmutatja, milyen módon és céllal használták fel ezeket a közgazdászok és történészek saját elemzéseikben. / === / The accounts of early bubbles and crises are becoming fashionable again in economic discourse during the recent downturn. The article, having looked at the revival of macroeconomic debate provoked by the failure of current theory, sums up various interpretations of the Dutch tulip mania of 1634-7. These range from an outburst of popular madness, through an early example of an efficient financial market, to an instance of culture shock. Some well-known anecdotes about tulip mania are traced back to their original sources, and the article explores the various patterns and intentions in the use economists and historians have made of them.