Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 48 for “"Bubble formation"”.
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Cavitation and Bubble Formation in Water Distribution Systems
… valves, faulty instrument readings due to bubbles, and reports of premature pipe failure; inclusion of gaseous cavitation phenomena can better explain these events. Gaseous cavitation can be expected to influence corrosion in water distribution pipes. Bubbles can form within the water …
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Water Treatment: Fundamentals and Practical Implications of Bubble Formation
Water utilities can experience problems from bubble formation during conventional treatment, including impaired particle settling, filter air binding, and measurement as false turbidity in filter effluent. Coagulation processes can cause supersaturation and bubble formation by converting …
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Effects of Dissolved Gas Supersaturation and Bubble Formation on Water Treatment Plant Performance
Gas bubbles that form within water treatment plants can disrupt drinking water treatment processes. Bubbles may form whenever the total dissolved gas pressure exceeds the local solution pressure, a condition termed dissolved gas "supersaturation." This project investigated how bubble formation …
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Gas assisted injection moulding: Experiment and simulation. Industrial machine experimental studies of the effect of process variables on gas bubble formation, and with simulation based upon a pseudo-concentration method.
… of ways, but here the penetration of a gas bubble through the polymer melt is of interest. A 3D fi nite element implementation of a pseudo concentration method is employed to simulate the primary penetration of the gas bubble. The wall thickness prediction is an important result since the …
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Fluid mechanics of bubble capture by the diving bell spider
… of its species, is used as inspiration for a bubble capture mechanism. Bubble mechanics are studied in the pursuit of a biomimetic solution for transporting air bubbles underwater. Careful experimentation is performed to understand the mechanics of bubble formation and capture. Investigation …
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Controllable vapor microbubbles for use in bioparticle actuation
… guidelines for using thermally formed microbubbles as a means of fluidic actuation. The use of microbubbles is attractive due to the simple fabrication and operation of such devices, however, prior work in this area was hindered by several issues inherent to vapor bubble formation that …
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Image Analysis of Air-bubble Injection (Front and Side View) into a Turbulent Liquid Stream
"This study concerns an air bubble injection experiments in a vertical upward annular channel in which a 0.4 mm hole was created to inject the air bubbles into the turbulent stream. Water was used as a testing fluid, and the experiments were performed at atmospheric pressure and room temperature. A …
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An overview of potential financial bubbles in the US financial markets
Financial bubbles have presented a challenge for the financial markets for a long time and caused steep losses for many investors. This thesis has two main goals relating to financial bubbles. The first is to try to determine if it is possible to find out if a financial bubble is forming. To …
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Additive manufacturing of glass using a filament fed process
… temperature. Furthermore, the mechanism of bubble formation in soda lime glass printing was also studied. Different regimes of bubble formation were found corresponding with different process parameters.</p> <p>Though the melting temperature of fused quartz is very high (~2300 ⁰C), 3D fully …
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The prediction of bubble defects in castings
… the entrainment, breakup and transport of gas bubbles in solidifying TiAl castings. The candidate has reviewed the literature, programmed in FORTRAN code, and validated a number of competing techniques for two phase flow relevant to the filling of moulds. He has developed a hybrid …
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Modelling and computational analysis of heat-transfer in multi-geometry and multi-phase flow of Newtonian and non-Newtonian fluids in pipes and channels
… multi-phase flow problems involving boiling and bubble formation. Newtonian fluids, Newtonian-Fluid-Based- Nanofluids, and non-Newtonian fluids are all considered in the thesis. The Newtonian-Fluid-Based Nanofluids (NFBN) are designed from the homogeneous mixing of a Newtonian base-fluid with …
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Experimental analysis of boiling enhancement from surfactant addition with electric fields
… alter the surface energy interaction during bubble formation at nucleation sites. The surfactants initially enhance the heat transfer coefficient at the onset of nucleate boiling due to higher nucleation density and higher bubble departure frequency. The critical heat flux, on the other hand, …
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Investigation into the behaviour of a wash-coated PGM-based catalyst layer onto micro-channel reactors for the steam reforming of methane
… forces in the liquid. This resulted bubble formation and due to the high viscosity of the suspension due to the presence of the polyvinyl alcohol (PVA) binder the bubbles remained during the wash-coating process which is thought to have adversely affected the wash-coats adhesion. …
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An Experimental Investigation of Critical Heat Flux Performance of Hypervapotron in Subcooled Boiling
… surfaces. It was developed on observations of bubble formation, departure and coalescence, and on the confirmation of nucleation structure on the heating surface. Finally, a numerical code was successfully developed to give CHF predictions for hypervapotron configurations. The simulation …
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Electrostatic simulations of interactions between a scanning probe and quantum Hall liquid
… applied, and tip voltages. We modelled quantum bubble formation under the metal probe, incompressible strip formation beneath the edge of the metal gate, and 2DEG density profile under the influence of donors in magnetic field. In order to model complex geometry systems, but also optimize …
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System dynamics, market microstructure and asset pricing
… among loops stabilize markets and limit bubble formation. Model simulation results show, that not only the numerical limit of leverage, but also regulatory definition of leverage matters. Market stability can be achieved faster with lower system-wide and narrow definition of leverage. To …
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Molecular Interfaces and Heterogeneous Bubble Nucleation From Heated Surfaces At Nanoscale
… liquid. Therefore, it is important to understand bubble formation, its onset, and behavior over time to advance thermal management applications utilizing nanoscale characteristics. This work aims to investigate bubble nucleation and growth on heated surfaces and understand heat transfer at …
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Modelling the two-phase plume dynamics of CO2 leakage into open shallow waters
… the North Sea. New sub-models are developed for bubble formation and drag coefficients using in-situ measurements from videos of the Quantifying and monitoring potential ecosystem Impacts of geological Carbon Storage (QICS) experiment. Existing sub-models such as Sherwood numbers and plume …
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Non-linear, non-spherical bubble dynamics near a two fluid interface
The interactions of bubbles with rigid and free boundaries have been well documented. Toroidal bubble formation has been observed, with jetting directed toward and away from the two types of interface respectively. This work generalises these interactions by studying the effect of a two fluid …
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THE DESIGN, CONSTRUCTION, AND VALIDATION OF NOVEL ROTATING WALL VESSEL BIOREACTORS
… avoid, and deleterious modes of failure is the formation of bubbles. The appearance of even a small bubble in an RWV disrupts the crucial laminar flow shells present in the RWV, inducing a high-shear environment incapable of maintaining microgravity or producing true spheroids. The difficulty of …
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