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Showing 1 to 20 of 275 for “"Yield stress"”.
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Extending yield-stress fluid paradigms
In this thesis, we present two new paradigms for yield-stress fluids; the first organizes the existing understanding of the various ways to achieve a yield-stress fluid into a useful methodology for the design of rheologically complex materials; the second is based on the discrepancy in the …
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Impact cratering with yield-stress fluids
… involve water and granular media, and very few yield-stress fluids like soft materials. Except for the common experiment of a water drop impacting a water pool, in most works the impactor is a solid, non-deformable sphere. However, in the relevant geological process, and in most other …
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Rheology and design of yield-stress fluids
Yield-stress fluids are materials that transition from solid-like to fluid-like at a critical applied stress and are currently the most utilized rheological phenomenon. Yield-stress fluids have found use in drug delivery, food products, batteries, surface coatings, 3D printing materials, and many …
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Designing devices using electro-active yield stress fluids
… the rheo-electrical properties of electro-active yield stress fluids (EAYS) lies at the heart of enabling the design of a number of novel applications such as smart valves and semi-solid flow batteries. This thesis explores the rheological and electrical properties of EAYS fluids, with a focus on …
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Effect of vibration on yield stress of concrete for 3D printing applications
… be solved by using vibration to control the yield stress of concrete. Research has shown that concrete behaves like a Newtonian fluid during vibration at low shear rates. The primary objective of this research is to qualitatively understand the effects of vibration on the fresh properties of …
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When sticky fluids do and do not stick: yield-stress fluid drop impacts
… we use high-speed video to experimentally study yield-stress fluids impacting three types of surfaces that exhibit distinct and fascinating behaviors: coated surfaces, permeable surfaces, and hot surfaces. A variety of common materials such as peanut butter, toothpaste, paints, foams, printing …
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Shaking, slamming, and vibrating yield-stress fluids: Inducing particle motion in rheologically-complex materials
Made available in DSpace on 2018-03-13T15:25:20Z (GMT). No. of bitstreams: 9 KOCH-DISSERTATION-2017.pdf: 50624702 bytes, checksum: f3e68c494df9420b9f4d386c1b05f99c (MD5) jakoch2_LaTeX_src.zip: 52005063 bytes, checksum: 9af5cc375da07488897271c67c680e44 (MD5) LICENSE.txt: 4208 bytes, checksum: …
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A motion of freely oscillating droplet of a yield stress fluid: analysis and numerical studies
… small-amplitude oscillations of a droplet of a yield stress fluid under the action of surface tension forces. The problem is treated both analytically and numerically. In particular, we address the question if there exists a finite stopping time for an unforced motion of a yield stress fluid …
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Meaningful descriptions of thixotropy and extensibility for yield-stress fluid drop impact on thin films
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-11-15 without embargo terms
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A viscoelastic constitutive model for thixotropic yield stress fluids: asymptotic and numerical studies of extension
… value problem with a prescribed elongational stress is solved in the limit of large relaxation time. This gives rise to multiple time scales. If the initial stress is less than a critical value, the initial elastic elongation is followed by settling to an unyielded state at the slow time …
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High performance simulations of yield stress fluids in a structured adaptive mesh refinement framework with embedded boundaries
… of non-Newtonian liquids characterised by their yield stress. Unless an external stress is applied which is larger than this threshold value, the fluid does not flow, but exhibits rigid body behaviour. Above the yield stress, applied forces cause viscous deformation. Such fluids play important …
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Bulk and micro-scale rheology of an aging, yield stress fluid, with application to magneto-responsive systems
… array of rheological properties, including a yield stress, viscoelasticity, and a shear-thinning viscosity, can be achieved at very low concentrations in aqueous dispersions (~ 1 w%). Though this behavior has been investigated extensively using traditional 'bulk' rheology, a number of …
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High performance lattice boltzmann method yield-stress calculations based on intravital images of clot formation in live mice
… risks. The ability to access hydrodynamics stresses at which thrombus structure is likely to embolize can provide insight into the thrombogenesis process. Interestingly, the viscoelastic behavior exhibited by the thrombus resembles that of a Bingham fluid - a material that behaves as a rigid …
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Concrete Rheology
… on the rheological parameters of yield stress, plastic viscosity, and apparent viscosity. The objective of this work was not only to measure the effects on rheology by the variables, but also to predict some of the same measured rheological parameters. The modeling of yield stress …
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YIELDING PHENOMENA IN MICROGEL SUSPENSIONS ACROSS LENGTH SCALES
… responses depending on the timescale or applied stress. These properties significantly impact practical functionalities and user experiences, such as spreadability, sensory perception, active ingredient release, and long-term stability. Yield stress fluids (YSF) specifically behave like solids …
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Effect of nano-fibers on the stress-strain behavior of semi-crystalline poly(ethylene terephthalate) at different strain rates
… with various amounts of nano-fibers added. The stress-strain behavior for each material at several strain rates is presented. A typical stress-strain curve consists of a relatively steep rise in stress at small strains where the slope is the Young's Modulus. Then, the stress reaches a maximum …
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Development of a constrained piston method for compression testing of carbon foams
… gathering mechanical strength properties, namely yield stress, modulus, and energy absorption all during a single compression test. Several carbon foams were tested using both the novel constrained method (developed herein) and the conventional unconstrained technique to compare the results. …
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Rheological characterization and modeling of Laponite gels with application to snug-like locomotion
… rheometer through various testing methods: stress sweep, creep tests, and large amplitude oscillatory shear tests, defined as LAOS. Concentrations of 1%, 2%, 2.5%, 3%, and 4% wt. of Laponite and distilled water solutions were tested. Laponite gels over 1% wt. concentrations were …
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Formwork pressure and rheology of self consolidating concrete
… and cement paste mixes like workability, static yield stress gain and temperature change over time were evaluated and correlated with the formwork pressure data. The mix parameters for the concrete, mortar mixes like water to cementitious ratio, the addition of fly ash, aggregate content, maximum …
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Three Experiments on Complex Fluids
… is an investigation of the start-up flow and yielding of a simple yield-stress fluid (Carbopol 940) in a vertical pipe. The Carbopol was displaced from below by an immiscible Newtonian liquid (Fluorinert FC-40) injected at a constant, controlled rate. Rough and smooth-walled pipes were used to …
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