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 54 for “"SUBLAYER"”.
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Riblets in the viscous sublayer : Optimal Shape Design of Microstructures
… that these microstructures remain in the viscous sublayer where the flow equations are the 3D incompressible, steady state Navier-Stokes equations with a Couette in- and outflow determinated through two boundary conditions, the no-slip condition on the lower boundary and the friction condition on …
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An investigation into the use of a clear coat sublayer on concrete surfaces to prevent scarring
… was conducted. The viability of using clear coat sublayers as a means of protecting the concrete from waterblasting was also investigated. Scanning electron microscopy was employed to view the interface between paint and concrete both with and without the sublayers. The investigation found that a …
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On a Joint Physical Layer and Medium Access Control Sublayer Design for Efficient Wireless Sensor Networks and Applications
Wireless sensor networks (WSNs) are distributed networks comprising small sensing devices equipped with a processor, memory, power source, and often with the capability for short range wireless communication. These networks are used in various applications, and have created interest in WSN research …
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Evaluation of the Effect of Microporous Sublayer Design and Fabrication on Performance and Adhesion in PEM Fuel Cell Assemblies
… (PEMFC) contains a layer called the microporous sublayer (MSL). The MSL is a mixture of carbon black and polytetrafluoroethylene (PTFE), which is typically applied to the gas diffusion layer (GDL). The composition (wt.% PTFE) and loading (mg/cm2) can be varied to optimize the electrochemical …
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Silicon Carbon(001) Gas-Source Molecular Beam Epitaxy From Methyl Silane and Silicon Hydride: The Effects of Carbon Incorporation and Surface Segregation on Growth Kinetics
… consisting of alternating Si-rich and C-rich sublayers form spontaneously during the gas-source molecular beam epitaxial growth of Si1-y Cy layers from constant Si2H6 and CH 3SiH3 precursor fluxes. The formation of a self-organized superstructure is due to a complex interaction among competing …
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Experimental analysis of flow and turbulence characteristics in oscillatory boundary layers from LDV measurements
… the boundary layer and even inside the viscous sublayer in some cases. A special set-up was built involving two LDV probes and a refraction-correcting device to be able to measure all three velocity components (u, v, w) simultaneously. From the velocity measurements, flow characteristics were …
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The Velocity-Concentration Relationship in Turbulent Mass Transfer to a Wall
… layer is completely contained within the viscous sublayer.
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The Influence of Pore Fluid on The Stability of a Rock Mass With a Weakened Zone
… slab of fluid-infiltrated rock which contains a sublayer of weakened material. Inelastic deformation is allowed throughout the slab, with strain softening possible. The boundaries are loaded in plane strain by a uniform, constant compressive stress and a constant tangential displacement rate. The …
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Frictional resistance of concrete on a geocomposite material
… its frictional behavior is comparable to other sublayer systems. The connections between concrete and Tendrain found in these study are the preliminary steps to formulating slab design which utilizes the material as a sublayer. This study, along with future subgrade reaction analysis, can be …
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Experimental study of low-order models of highly-irregular roughness and their impact on turbulent boundary layers
… in a wall-parallel plane deep in the roughness sublayer (y = 0.047δ). Comparison of both single- and multipoint statistics (mean velocity and Reynolds normal and shear stresses) as well as quadrant analysis of the instantaneous events contributing to the mean Reynolds shear stress from the 2-D …
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Experimental Study of Low-Order Models of Highly-Irregular Roughness and Their Impact on Turbulent Boundary Layers
… measurements deep within the roughness sublayer at y = 0.047delta reveal a wealth of information about roughness-induced effects, including the tendency of the roughness to promote 'channeling' of the flow in the form of low- and high-momentum pathways as noted in contour maps of the …
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Experimental Investigation of Highly Irregular Roughness Effects in Wall Turbulence
… wall, both within and outside the roughness sublayer, to further assess the possibility of structural modifications due to roughness. Hairpin vortex packets, commonly observed in smooth-wall turbulence, are observed often in the outer layer of the rough-wall flow. As in smooth-wall flow, …
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Open-Channel Flow With Roughness Elements of Different Spanwise Aspect Ratios: Turbulence Structure and Numerical Modeling
… turbulence structure of the so-called roughness sublayer through the associated eddy-shedding process. The present work makes use of acoustic Doppler anemometry and traditional hot-film sensors to investigate the structure of the turbulence induced by roughness elements with three different …
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Surfactant dynamics at interfaces : a series of second harmonic generation experiments
… consists of a topmost monolayer and an adjacent sublayer. The dissipative process is due to the molecular exchange between both layers. The assessment of this model required the design of an experiment that discriminates between the surface compositional term and the sublayer contribution. Such …
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Turbulent Boundary Layer over a Piezoelectrically Excited Traveling Wave Surface
… layer is pushed off the wall, and the viscous sublayer is thickened, indicating a reduction in shear stress. Analysis of the boundary layer at positions phase-locked to the wave oscillation suggests that the traveling waves induce a phase-lag effect in the flow. This phase-lag produces a …
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Studies of the Interaction Between Drag-Reducing Polymers and a Turbulent Flow Field Using Pulsed Image Velocimetry and FENE Bead-Spring Model
… in the buffer zone but not in the viscous sublayer. This increase in the viscosity results in damping of small eddies and an increase in the thickness of the buffer layer and reducing the drag.
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Neuronal and Vascular Degeneration of the aging retina in the 3xTg-AD mouse
… accompanying AD. Chapter two explores retinal sublayer thickness changes by optical coherence tomography (OCT) in young to middle age transgenic and control mice and suggests that a pattern of retinal sublayer changes may detect AD's preclinical stage and distinguish AD- from …
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Effects of boundary roughness on turbulence in uniform open channel flow
… the near wall region but also within the viscous sublayer. Using the data from both the log law and linear viscous sublayer fits allowed for more reliable computations of shear stresses as well as a better understanding of how turbulence behaves over the full range of the flow. Previous studies …
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An Experimental Study of Turbulent Boundary Layers Subjected to High Free-stream Turbulence Effects
… coefficient (Cf) was deduced from the viscous sublayer. The difference between the U_tau obtained in the viscous sublayer mean velocity profile and the U_tau obtained in the semi-log layer was 1.5%. The skin friction coefficient was determined to increase by 10.5% when the two-dimensional …
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Studies of the Wall Shear Stress in a Turbulent Pulsating Pipe Flow
… and the turbulence fluctuations in the viscous sublayer, which is not described by present theories of turbulence.
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