Rheology of Concentrated Suspensions of Spheres PDF Download

Author: Joseph Harold Smith
Publisher:
ISBN:
Category :
Languages : en
Pages : 360

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Author: Li Chau Huang
Publisher:
ISBN:
Category : Polymers
Languages : en
Pages : 368

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Author: Sheau Van Kao
Publisher:
ISBN:
Category :
Languages : en
Pages : 26

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A coaxial cylinder viscometer was used to measure the rheological behavior of concentrated suspensions of glass spheres in a nonpolar liquid (Liquid polybutadiene), a polar liquid (glycerol), and a liquid of medium polarity. The glass beads had untreated surfaces, surfaces with absorbed octylamine, or hydrophobic surfaces prepared by treating the surfaces with dimethyldichlorosilane. All the suspensions were Newtonian, except for the suspension of silane treated beads in glycerol which was pseudoplastic. Contact angle and sedimentation measurements indicate that the glycerol-silane treated beads system contained beads in an agglomerated state. The viscosities of the suspensions obey a Mooney type equation. In the Newtonian systems all the suspensions containing treated glass surfaces had lower relative viscosities than the analogous systems with untreated surfaces.

Author: Sheau Van Kao
Publisher:
ISBN:
Category :
Languages : en
Pages : 24

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A modified Stormer viscometer was used to study the flow behavior of suspensions of glass beads in liquids of different polarity over the volume concentration range from 50 to 60 percent. The flow behavior was pseudoplastic in some cases but rigid pastes were observed in other cases in this concentration range. The nature of the particle surface affected the flow behavior in the same manner as at lower concentrations. At still higher concentrations (> 60 v/o), a yield stress was found for all systems. Slipping occurred in the viscometer, and this phenomenon sets an upper limit for the study of concentrated suspensions.

Author: Francis A. Gadala-Maria
Publisher:
ISBN:
Category : Rheology
Languages : en
Pages : 314

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Author: R. O. Maschmeyer
Publisher:
ISBN:
Category :
Languages : en
Pages : 19

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A review and summary are presented on the existing scientific and technical literature on the viscosity and elasticity of concentrated fiber suspensions, including reinforced plastics. Also discussed is the experimental capillary rheometry of model suspensions of glass fibers in viscous silicone oils. At high volume fraction fibers such suspensions are pseudoplastic, exhibit a yield stress in shear, have large capillary entrance corrections, but show no die swell. A brief account is given of the influence of fiber breakage on suspension viscosity in capillary flow and on the best choice of technique for mixing such suspensions. (Author modified-PL).

Author: Sheau Van Kao
Publisher:
ISBN:
Category :
Languages : en
Pages : 28

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Small amounts of a second immiscible liquid, water, were introduced into suspensions of glass beads (untreated or surface treated with dimethyldichlorosilane) in liquid polybutadiene. Water formed liquid bridges between the particles and caused the suspensions containing untreated beads to agglomerate. These large agglomerates changed the flow behavior from Newtonian to pseudoplastic. The extrapolated Bingham yield stress went through a maximum as the amount of water increased. Surfactants first decrease the pseudoplastic behavior, and then at higher concentrations, surfactants cause the suspensions to become Newtonian in behavior. A theory was developed in an attempt to explain the experimental results. The theory predicts pseudoplastic flow behavior for agglomerated suspensions, but the quantitative correlation between theory and experiment is not satisfactory.

Author: Jan Mewis
Publisher: Cambridge University Press
ISBN: 0521515998
Category : Science
Languages : en
Pages : 417

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Presented in an accessible and introductory manner, this is the first book devoted to the comprehensive study of colloidal suspensions.

Author: Dennis P. Kalman
Publisher:
ISBN: 9781124240909
Category : Colloids
Languages : en
Pages :

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The relationship between colloidal suspension microstructure and rheology is investigated to provide a solid understanding of the nonlinear rheology of concentrated suspensions, with a focus on shear thickening. These suspensions are also studied as a treatment to woven fabric in body-armor applications, where the insight from microstructural measurements is used to attempt to improve the application. The colloid and suspension properties are characterized via SEM, DLS, SANS, USANS, and rheometry. The rheology is mapped onto an effective hard-sphere model with the addition of a yield stress. An additional excluded volume shell, as measured by SANS and USANS structural measurements, accounts for interparticle interactions due to surface forces arising from the stabilizing layer on the particles. The microstructure of these near hard-sphere concentrated, shear-thickening colloidal dispersions are measured via SANS and USANS as a function of volume fraction, shear rate, and particle size. Special Rheo-SANS, flow-SANS, and flow-USANS instruments are developed and validated to measure microstructure in flowing systems. Structures measured via USANS show a cluster peak that arises from hydrocluster formation in concentrated, shear thickening suspensions. Structure measurements in SANS via 1-d averaged analysis and analysis of the 2-d structure corresponds to that expected from Stokesian Dynamics simulations. Micromechanics theory via a Stress-SANS law is used to calculate rheology from the microstructure for comparison. As the rheology calculated from the SANS data qualitatively agrees with that of the suspension and the structures seen correspond to those expected from simulations, strong confirmation of the hydrocluster mechanism for shear thickening is observed. This improved knowledge of the hydrocluster structure is used to develop an elastohydrodynamic theory for the limiting viscosity at high shear stresses due to particle deformations in the hydrocluster. Measurements of particle modulus give consistent application of this elastohydrodynamic model to suspensions studied in this thesis. In addition, the model is applied to widely varying suspensions, including those of hard mineral particles, polymer particles, microgels, and emulsions and consistent results are seen. The results of these fundamental studies of how particle size, concentration, and hardness affect suspension microstructure and rheology are used to engineer shear thickening fluid treated textiles, suitable for various types of protective devices.

Author: Francisco Chinesta
Publisher: Elsevier
ISBN: 0081008120
Category : Science
Languages : en
Pages : 398

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Book Description
This book provides a review of the current understanding of the behavior of non-spherical particle suspensions providing experimental results, rheological models and numerical modeling. In recent years, new models have been developed for suspension rheology and as a result applications for nanocomposites have increased. The authors tackle issues within experimental, model and numerical simulations of the behavior of particle suspensions. Applications of non-spherical particle suspension rheology are widespread and can be found in organic matrix composites, nanocomposites, biocomposites, fiber-filled fresh concrete flow, blood and biologic fluids. Understand how to model and predict the final microstructure and properties of particle suspensions Explores nano, micro, meso and macro scales Rheology, thermomechanical and electromagnetic physics are discussed