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Showing 1 to 20 of 21 for “"yield-stress fluids"”.
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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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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 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
Viscoplastic fluids are a class 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. …
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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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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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Thixotropic-viscoelastic rheological fingerprints in large amplitude oscillatory shear
… in classifying thixotropic versus “simple” yield stress fluids with no observable thixotropy. Having established the signature of the simplest model that exhibits the features of interest, we then proceed to make two modifications, focusing on the fundamental characteristics of the kinetic …
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Rheology and Processing of Animal and Plant-Based Dense Emulsions
… available vegan mayos can emulate the apparent yield stress and shear thinning of yolk-based mayonnaise by the combined influence of plant-based proteins (like chickpea) and polysaccharide thickeners. However, we show that the dispensing and dipping behavior of egg-based and vegan mayos display …
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Engineered interfaces controlling the nucleation and flowability of complex fluids
… mobility of water and even low surface tension fluids was demonstrated using surfaces with engineered chemistry and textures, with driving forces ranging from electrical, magnetic, gravitational, as well as Marangoni forces. Engineered surfaces were also shown to control and improve processes …
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Extrusion Printing of Carbon Nanotube Inks, from Rheology to Electronics
… particularly focusing on elastoviscoplastic yield stress behavior, observing scaling laws for flow behavior, and denoting rheometric signatures of ink phase, solution quality, and printability. With further attention to rheometry, a modified vane tool is introduced that has an optimized …
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YIELDING PHENOMENA IN MICROGEL SUSPENSIONS ACROSS LENGTH SCALES
… as food and personal care products, are complex fluids with intricate mechanical properties, blending viscous and elastic behaviors, and exhibiting different responses depending on the timescale or applied stress. These properties significantly impact practical functionalities and user …
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THE YIELDING TRANSITION IN SOFT AMORPHOUS SOLIDS UNDER OSCILLATORY SHEAR: FROM MICROSCOPIC REARRANGEMENTS TO MACROSCOPIC FAILURE
Complex fluids such as polymer solutions, colloidal suspensions, emulsions, or foams are ubiquitous in our daily lives. These soft materials often display a non-trivial response to mechanical perturbations, which depends both on the time scale and the amplitude of the applied perturbation. In …
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Suspension, yielding, microstructure and applications of bacterial cellulose dispersion
… suspension abilities, because they possess a yield stress that makes the fluid elastic until a threshold stress is exceeded. Yield stress fluids have been widely studied, but the local aspects of yielding, and the effects of particle shape on suspension performance are still not …
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Characterize the molecular dynamics of materials for 4D printing
… and 2) translation of rheological behavior of yield stress fluids to quality of printing. These printing-centric approaches are combined in order to advance the field of 4D printing towards fabrication of spatiotemporal patterning to fabricate 4D structures. Polymer/clay composite inks are the …
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Understanding self-assembly and flow heterogeneities in poloxamer wormlike micelles
… typically observed in gels, including a yield stress and viscoelastic aging. Combined shear rheology and particle tracking velocimetry (rheo-PTV) measurements revealed this solution of WLMs formed shear bands in startup flows, accompanied by elastic instabilities and wall slip. The …
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Rheology of bubbly liquids containing a non-Newtonian continuous phase
… that belongs to a family of yield stress fluids known as Carbopols. Bubbly liquids with air volume fractions in the range 𝜙<sub>a</sub> = 0 − 0.5 were produced by whisking the continuous phase in a planetary mixer. Aeration profiles describing how 𝜙<sub>a</sub> evolved were …
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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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Modeling the flow of non-Newtonian fluids in packed beds at the pore scale
… flow as well as displacement by less viscous fluids. The transient displacement is used to investigate important viscous fingering patterns. While simple boundary conditions are typically imposed in network modeling (e.g. a pressure gradient in one dimension), a more general approach has been …
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