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 165 for “"shear-thinning"”.
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Novel Shear-Thinning of Aged PDMS/Fumed Silica Admixtures and Properties of Related Silicone Elastomers
… solid admixture that even long periods of high shear mixing will not thin. In the course of the current work it was noted that after a period of storage certain solid admixtures would become viscous liquids when subjected to additional high shear mixing. It was further found that the required …
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A Novel Shear Thinning and Thixotropic Plga Micro Particulate Suspension System for Controlled Drug Delivery
… micro particle suspension and a thixotropic and shear thinning behavior for the ease of injectability but further controlled the initial drug release. Biocompatibility studies indicated that the <em>in situ</em> PLGA micro particulate implant formulation containing PCL crystallites is safe and …
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INTERFACIAL DYNAMICS OF DROP COALESCENCE AND IMPINGING LIQUID JETS: EFFECT OF VISCOUS, MARANGONI AND SHEAR-THINNING STRESSES
… frequently involve the use of complex fluids -- shear-thinning or viscoelastic non-Newtonian liquids, which often contain surfactants either as additives or as contaminants. This Thesis reports high-fidelity simulations of unsteady free-surface flows of complex fluids. The objec- tive is to …
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INTERFACIAL DYNAMICS OF DROP COALESCENCE AND IMPINGING LIQUID JETS: EFFECT OF VISCOUS, MARANGONI AND SHEAR-THINNING STRESSES
… frequently involve the use of complex fluids -- shear-thinning or viscoelastic non-Newtonian liquids, which often contain surfactants either as additives or as contaminants. This Thesis reports high-fidelity simulations of unsteady free-surface flows of complex fluids. The objec- tive is to …
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Large Scale Simulation of Plate-Like Particle Suspensions
Shear thinning and shear thickening of suspensions of plate-like particles are studied. It is found that shear thinning is caused by both the decrease of the strength of the Brownian motion and the decrease of the hydrodynamic contribution to the viscosity resulting from the increasing particle …
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Swimming in slime
… We compare the swimming speeds of viscoelastic shear thinning, shear thickening and Newtonian fluids for a fixed propagating wave speed. We then compare the swimming speeds of these same fluids for a fixed rate of work per wavelength. In the latter situation, we find that a shear thinning fluid …
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Transfer and Filling of Non-Newtonian Liquids in Printing and Coating Processes
… there. We further examine the influence of shear thinning and strain hardening on liquid transfer between two flat plates using flow visualizations. We observe that shear thinning can be exploited to significantly enhance liquid transfer from a less-wettable plate to a more-wettable one, and …
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Direct Simulations of Fluid-Particle Flow in Newtonian and non-Newtonian Fluids Using Coupled Lattice Boltzmann and Discrete Element Methods
… denser oblate particle suspension subject to the shear flow. A connection between the micro-structure statistics and the suspension viscosity is proposed. Second, the shear rate effects on the finer oblate particle suspension viscosity are studied. The viscosity of the suspension is observed to …
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The rheological properties of aqueous polyacrylamide solutions
… measurements of steady-state behavior, transient shear stress and yield stress response, thixotropic, creep recovery, and dynamic responses for each concentration. The findings resulted in several conclusions regarding the rheological properties of polyacrylamide solutions. They have shown a …
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A computational fluid dynamics study of two-phase flows in the presence of surfactants
… numbers. Both fluids can be Newtonian or shear-thinning, and surfactants are soluble in the adsorption-desorption limit. A drop in the co-flowing geometry typically breaks up at the primary neck. The drop breaks faster with smaller volumes as the outer flow rate increases or the drop …
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Two-Dimensional Transient Flows and Stability of Concentrated Suspensions of Clay Particles and Rheology
… using a state-of-the-art rheometer show that the shear history of concentrated suspensions of clay particles can be divided into three regions: solid-rigid, nearly Newtonian, and shear-thinning regions. The nearly Newtonian region is very narrow in shear rate compared to the shear thinning region. …
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Effect of nonionic surfactant (X-100) on the rheological properties of aqueous polyacrylamide solutions
… creep and recovery, thixotropy, transient shear stress response, and dynamic response. Results have shown a dramatic decrease in the surface tension with increasing surfactant up to the critical concentration. Polyacrylamide solutions have shown three different behaviors, a first Newtonian …
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Experimental and Analytical Investigation of Particle Dynamics in Newtonian and non-Newtonian Fluids in a Taylor-Couette Cell
… the behavior of particle sedimentation under shear conditions in a controlled environment.</p> <p>Particle Image Velocimetry (PIV) and Manual Particle Tracking (MPT) are employed to assess how rotational speeds and particle sizes influence the settling dynamics of heavy particles. The primary …
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Rheology and Microstructure of Concentrated Suspensions of Plate-Shaped Colloidal Particles
… equal to 8. These suspensions demonstrate shear thickening at $\phi \ge$ 0.50 and also have a shear history dependent elastic modulus, G$\sp\prime.$ In the shear thinning region G$\sp\prime$ decreases with increasing shear rate. In the shear thickening region the modulus increases rapidly. …
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The dynamic properties of concentrated charge stabilized suspensions
… are found to agree. Yielding and catastrophic shear thinning where the suspension viscosity decreases discontinuously with increasing shear stress are measured with both constant stress and constant strain rate rheometers.
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CFD studies of complex fluid flows in pipes
… rise to substantial enhancements in flow for shear thinning and viscoplastic fluids, while shear thickening fluids experienced flow retardation. The flow enhancement was found to depend on vibration frequency and amplitude, fluid rheological properties, and pressure gradient. These vibrations …
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Flow Behavior of Sparsely Branched Metallocene-Catalyzed Polyethylenes
… branching are considered with respect to the shear and extensional rheological properties, the melt fracture behavior, and the ability to accurately predict the flow through an abrupt 4:1 contraction geometry. The effects that sparse long-chain branching (M<sub>branch</sub> > M<sub>c</sub>) …
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The modeling and characterization of a Lorentz-force actuator for needle-free injection
… a measured viscosity of 2.5 Pa-s and exhibited shear thinning at a shear rate of about 1000 s-1. Shear thinning has a large effect on the required pressure for injecting poly(ortho) ester at sufficient velocities. Finally, a benchtop experiment was designed and built to measure the force output …
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Implications of Nanofiber Length and Polydispersity on Flow Alignment
… insight into their colloidal behavior, shear response, and alignment mechanisms remain limited. Additionally, few experimental techniques can probe nanoscale orientation under dynamic conditions, making it difficult to correlate rheological properties with shear-induced alignment. This …
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Tri-helical direct gravure coating
… model for the fluid (specifically a shear thinning power law formulation). Analysis of the application of shear thinning fluids to the moving substrate is also conducted. The base model developed is that for rectangular grooves of zero pitch, which takes the form of an analytical …
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