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 38 for “"thixotropic."”.
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Slowly varying pipe flow of thixotropic fluids
In this thesis we study lubrication flows of thixotropic and antithixotropic fluids in two flow problems: unsteady flow in a slowly varying 3D pipe, and oscillating flow in a uniform cylindrical pipe. We consider two fluid models which exhibit interesting non-Newtonian behaviour: the viscous …
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Mathematical modelling of thixotropic and antithixotropic fluids
… Specifically, we investigate these problems for thixotropic and antithixotropic fluids described by Mewis and Wagner's [Advances in Colloid and Interface Science, 147-148, 214-227 (2009)] general structure parameter model together with a version of the constitutive law proposed by Moore …
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Undrained strength anisotropy of an overconsolidated thixotropic clay
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1987.
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Thixotropic-viscoelastic rheological fingerprints in large amplitude oscillatory shear
… of constitutive models that exhibit both thixotropic and viscoelastic phenomena. We demonstrate this use of LAOS by first examining the strain controlled LAOS (LAOStrain) response of a Thixoelastic Jeffreys model. First, this canonical model is defined for capturing both viscoelasticity …
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Mathematical Analysis on the PEC model for Thixotropic Fluids
… establishes mathematical analysis on a thixotropic yield stress fluid using a viscoelastic model under the limit that the ratio of retardation time versus relaxation time approaches zero. The differential equation model (the PEC model) describing the evolution of the conformation tensor …
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A Novel Shear Thinning and Thixotropic Plga Micro Particulate Suspension System for Controlled Drug Delivery
… stability of the 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 …
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A viscoelastic constitutive model for thixotropic yield stress fluids: asymptotic and numerical studies of extension
… for analyzing a viscoelastic model that displays thixotropic behavior as a model parameter gets very small. The model is the partially extending strand convection model, originally derived for polymeric melts that have long strands that get in the way of fully retracting. A Newtonian solvent is …
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DESIGN AND PERFORMANCE OF SELF-CONSOLIDATING AND THIXOTROPIC ULTRA-HIGH-PERFORMANCE CONCRETE FOR INFRASTRUCTURE CONSTRUCTION AND REHABILITATION
<p>"The objective of this research is to develop two classes of ultra-high-performance concrete (UHPC), one with self-consolidating consistency and the other with improved thixotropy. Tailoring the rheological properties of low yield stress UHPC can improve dispersion and orientation of steel …
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Time-resolved linear and non-linear rheology of thixotropic and aging complex fluids: Application to particulate and biopolymeric physical gels
… study shear-induced microstructural changes in thixotropic and gelling materials. We explore applications of the Gabor transform (a Short Time Fourier Transform (STFT) combined with a Gaussian window), for providing optimal joint time-frequency resolution of a mutating material’s viscoelastic …
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The application of a modified MacMichael viscometer in rheologic studies of montmorillonite clays
… observations. Generally, the gel structure of a thixotropic clay must be disturbed by shaking, pouring into a container for testing, and again upon insertion into the sample of the bob, spindle or paddle of the instrument. Also, these instruments yield a single point reading which is only a final …
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Rheological study of solutions of high concentrations of Carboxymethyl cellulose
… stress of Carboxymethyl Cellulose. Also, the thixotropic, viscoelastic behavior, and some of the dynamic responses were included. In order to accomplish this, a Haake-Rheostress 100, Cone-and-Plate Rheometer system was used to get a full set of rheological characteristics of high …
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Design of dense graded cold bituminous emulsion mixtures and evaluation of their engineering properties
… NH-10 emulsion have shown that it possesses a thixotropic behaviour. The thixotropic behaviour has been justified by the "complex flow" coefficient, a technique proposed by Traxler for bitumens. The viscosity of the emulsion is greatly influenced by the amount of binder and level of …
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Modelling Tremie Concrete Placement in Deep Foundations
… (CFD) and the Material Point Method (MPM). A new thixotropic model integrating the Papanastasiou-Bingham model with thixotropy equations was developed, enabling the simulation of thixotropic behaviour of Tremie Concrete in the Material Point Method framework. The novel model revealed a decline in …
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Effect of Rolling on Viscoelastic Fluids Using a Novel Testing Device
… to decrease, which is an expected behavior a thixotropic fluid. The motor oil, on the other hand, did not follow this trend even though it is a thixotropic fluid. As motor oil has a higher viscosity at lower shear rates, it is possible that the oil being was pushed out of the well containing …
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Novel Rheometric Techniques and Constitutive Models for Linear and Nonlinear Rheology: Applications to Polymeric Solutions and Colloidal Gels
… especially if the material properties are ‘thixotropic’ and change with time. Thus, part II of this thesis focuses on developing novel rheometric techniques that can robustly characterize time-varying rheological properties of complex fluids and soft solids. In Part I of this thesis, we …
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The rheology of silicon nanoparticle inks fro screen printing electronic devices
… in properties with angular frequency, as well as thixotropic behaviour. All showed shear thinning, with the more dilute inks showing a power law (Ostwald / de Waele model) behaviour dependence of complex viscosity on angular frequency. The flow behaviour of the inks was also seen to follow a …
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The rheological properties of aqueous polyacrylamide solutions
… 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 strong shear-thinning behavior for all …
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Effect of nonionic surfactant (X-100) on the rheological properties of aqueous polyacrylamide solutions
… range of tested solutions. The viscoelastic and thixotropic responses of the tested solutions were small. The effect of surfactant was generally low.
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The rheological complexity of waxy crude oils : yielding, thixotropy and shear heterogeneities
… model parameters to be determined for a thixotropic fluid. Through quantitative study of these phenomena, we reach several conclusions about how to characterize and model the rheology of a precipitate-containing crude oil. First, measurements of shear heterogeneities are important in …
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SYNERGISTIC EFFECT OF SHRINKAGE MITIGATING STRATEGIES ON PERFORMANCE OF FIBER-REINFORCED CEMENTITIOUS COMPOSITES
… shrinkage. Such materials can be flowable and thixotropic to promote pumpability and buildability for 3D printing"--Abstract, p. v</p>
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