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Markus Hütter - One of the best experts on this subject based on the ideXlab platform.
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Effect of Particle-size dynamics on flow properties of dense spongy-Particle systems
Journal of Rheology, 2018Co-Authors: Monica E.a. Zakhari, Markus Hütter, Patrick Patrick AndersonAbstract:Suspensions of poroelastic Particles are indispensable for applications where tailoring the overall properties is a necessity. The single-Particle elastic network gives rise to their elastic behavior, while the flow of the viscous solvent through the Particle structure gives rise to their rate-dependent behavior. In this work, we study the effect of the single-Particle elastic modulus and Permeability on the properties of the entire poroelastic-Particle suspension subject to simple-shear deformation. For this purpose, the dynamic two-scale model developed by Hutter et al. [Faraday Discuss. 158, 407–424 (2012)] is used. Upon deformation, both permeable- and impermeable-Particle suspensions undergo a transition from a glassy state to a shear-induced ordered state. On the one hand, the Particle Permeability is found to affect the rate at which the ordered state is reached. At a fixed elastic modulus, increasing the Particle Permeability prolongs the time scale at which shear-induced ordering occurs. On the o...
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Stress relaxation of dense spongy-Particle systems
Journal of Rheology, 2018Co-Authors: Monica E.a. Zakhari, Markus Hütter, Patrick Patrick AndersonAbstract:Spongy Particles have a permeable structure that allows them to undergo rate-dependent volume changes as their elastic network takes up or expels the viscous suspending solvent. Their ability to be jammed well above random close-packing makes them particularly attractive in applications where tailoring the overall properties is a requirement such as pharmaceuticals and foods. In this work, we independently vary the Particle modulus and the Particle Permeability to study their effect on the stress-relaxation behavior of jammed permeable-Particle suspensions. The dynamic two-scale model developed by Hutter et al. [Faraday Discuss. 158, 407–424 (2012)], which explicitly accounts for the Particle size dynamics, is used for this purpose. We perform flow-cessation simulations of dense permeable-Particle systems subjected to different preshear deformations. The stress relaxation occurs on shorter time scales in the case of permeable Particles compared to impermeable Particles. In terms of Particle dynamics, stress relaxation is found to be promoted primarily by the motion of the Particles within the cages formed by the surrounding Particles, rather than by cage escape. The stress-relaxation process is accelerated by the Permeability of spongy Particles, namely, due to the sustained volume change that was induced during preshear, which renders their cages less effective.Spongy Particles have a permeable structure that allows them to undergo rate-dependent volume changes as their elastic network takes up or expels the viscous suspending solvent. Their ability to be jammed well above random close-packing makes them particularly attractive in applications where tailoring the overall properties is a requirement such as pharmaceuticals and foods. In this work, we independently vary the Particle modulus and the Particle Permeability to study their effect on the stress-relaxation behavior of jammed permeable-Particle suspensions. The dynamic two-scale model developed by Hutter et al. [Faraday Discuss. 158, 407–424 (2012)], which explicitly accounts for the Particle size dynamics, is used for this purpose. We perform flow-cessation simulations of dense permeable-Particle systems subjected to different preshear deformations. The stress relaxation occurs on shorter time scales in the case of permeable Particles compared to impermeable Particles. In terms of Particle dynamics, stre...
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Effect of Particle-size dynamics on properties of dense spongy-Particle systems: Approach towards equilibrium.
Physical review. E, 2017Co-Authors: Monica E.a. Zakhari, Patrick D Anderson, Markus HütterAbstract:Open-porous deformable Particles, often envisaged as sponges, are ubiquitous in biological and industrial systems (e.g., casein micelles in dairy products and microgels in cosmetics). The rich behavior of these suspensions is owing to the elasticity of the supporting network of the Particle, and the viscosity of permeating solvent. Therefore, the rate-dependent size change of these Particles depends on their structure, i.e., the Permeability. This work aims at investigating the effect of the Particle-size dynamics and the underlying Particle structure, i.e., the Particle Permeability, on the transient and long-time behavior of suspensions of spongy Particles in the absence of applied deformation, using the dynamic two-scale model developed by Hütter et al. [Farad. Discuss. 158, 407 (2012)1359-664010.1039/c2fd20025b]. In the high-density limit, the transient behavior is found to be accelerated by the Particle-size dynamics, even at average size changes as small as 1%. The accelerated dynamics is evidenced by (i) the higher short-time diffusion coefficient as compared to elastic-Particle systems and (ii) the accelerated formation of the stable fcc crystal structure. Furthermore, after long times, the Particle-size dynamics of spongy Particles is shown to result in lower stationary values of the energy and normal stresses as compared to elastic-Particle systems. This dependence of the long-time behavior of these systems on the Permeability, that essentially is a transport coefficient and hence must not affect the equilibrium properties, confirms that full equilibration has not been reached.
Monica E.a. Zakhari - One of the best experts on this subject based on the ideXlab platform.
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Effect of Particle-size dynamics on flow properties of dense spongy-Particle systems
Journal of Rheology, 2018Co-Authors: Monica E.a. Zakhari, Markus Hütter, Patrick Patrick AndersonAbstract:Suspensions of poroelastic Particles are indispensable for applications where tailoring the overall properties is a necessity. The single-Particle elastic network gives rise to their elastic behavior, while the flow of the viscous solvent through the Particle structure gives rise to their rate-dependent behavior. In this work, we study the effect of the single-Particle elastic modulus and Permeability on the properties of the entire poroelastic-Particle suspension subject to simple-shear deformation. For this purpose, the dynamic two-scale model developed by Hutter et al. [Faraday Discuss. 158, 407–424 (2012)] is used. Upon deformation, both permeable- and impermeable-Particle suspensions undergo a transition from a glassy state to a shear-induced ordered state. On the one hand, the Particle Permeability is found to affect the rate at which the ordered state is reached. At a fixed elastic modulus, increasing the Particle Permeability prolongs the time scale at which shear-induced ordering occurs. On the o...
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Stress relaxation of dense spongy-Particle systems
Journal of Rheology, 2018Co-Authors: Monica E.a. Zakhari, Markus Hütter, Patrick Patrick AndersonAbstract:Spongy Particles have a permeable structure that allows them to undergo rate-dependent volume changes as their elastic network takes up or expels the viscous suspending solvent. Their ability to be jammed well above random close-packing makes them particularly attractive in applications where tailoring the overall properties is a requirement such as pharmaceuticals and foods. In this work, we independently vary the Particle modulus and the Particle Permeability to study their effect on the stress-relaxation behavior of jammed permeable-Particle suspensions. The dynamic two-scale model developed by Hutter et al. [Faraday Discuss. 158, 407–424 (2012)], which explicitly accounts for the Particle size dynamics, is used for this purpose. We perform flow-cessation simulations of dense permeable-Particle systems subjected to different preshear deformations. The stress relaxation occurs on shorter time scales in the case of permeable Particles compared to impermeable Particles. In terms of Particle dynamics, stress relaxation is found to be promoted primarily by the motion of the Particles within the cages formed by the surrounding Particles, rather than by cage escape. The stress-relaxation process is accelerated by the Permeability of spongy Particles, namely, due to the sustained volume change that was induced during preshear, which renders their cages less effective.Spongy Particles have a permeable structure that allows them to undergo rate-dependent volume changes as their elastic network takes up or expels the viscous suspending solvent. Their ability to be jammed well above random close-packing makes them particularly attractive in applications where tailoring the overall properties is a requirement such as pharmaceuticals and foods. In this work, we independently vary the Particle modulus and the Particle Permeability to study their effect on the stress-relaxation behavior of jammed permeable-Particle suspensions. The dynamic two-scale model developed by Hutter et al. [Faraday Discuss. 158, 407–424 (2012)], which explicitly accounts for the Particle size dynamics, is used for this purpose. We perform flow-cessation simulations of dense permeable-Particle systems subjected to different preshear deformations. The stress relaxation occurs on shorter time scales in the case of permeable Particles compared to impermeable Particles. In terms of Particle dynamics, stre...
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Effect of Particle-size dynamics on properties of dense spongy-Particle systems: Approach towards equilibrium.
Physical review. E, 2017Co-Authors: Monica E.a. Zakhari, Patrick D Anderson, Markus HütterAbstract:Open-porous deformable Particles, often envisaged as sponges, are ubiquitous in biological and industrial systems (e.g., casein micelles in dairy products and microgels in cosmetics). The rich behavior of these suspensions is owing to the elasticity of the supporting network of the Particle, and the viscosity of permeating solvent. Therefore, the rate-dependent size change of these Particles depends on their structure, i.e., the Permeability. This work aims at investigating the effect of the Particle-size dynamics and the underlying Particle structure, i.e., the Particle Permeability, on the transient and long-time behavior of suspensions of spongy Particles in the absence of applied deformation, using the dynamic two-scale model developed by Hütter et al. [Farad. Discuss. 158, 407 (2012)1359-664010.1039/c2fd20025b]. In the high-density limit, the transient behavior is found to be accelerated by the Particle-size dynamics, even at average size changes as small as 1%. The accelerated dynamics is evidenced by (i) the higher short-time diffusion coefficient as compared to elastic-Particle systems and (ii) the accelerated formation of the stable fcc crystal structure. Furthermore, after long times, the Particle-size dynamics of spongy Particles is shown to result in lower stationary values of the energy and normal stresses as compared to elastic-Particle systems. This dependence of the long-time behavior of these systems on the Permeability, that essentially is a transport coefficient and hence must not affect the equilibrium properties, confirms that full equilibration has not been reached.
Alírio E. Rodrigues - One of the best experts on this subject based on the ideXlab platform.
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Mass transfer mechanisms in Hyper D media for chromatographic protein separation
Biochemical Engineering Journal, 1998Co-Authors: M. Rendueles De La Vega, José M. Loureiro, C. Chenou, Alírio E. RodriguesAbstract:Abstract In order to elucidate the mass transfer mechanisms that allow improved performance for the separation of proteins of the chromatographic packing material Q Hyper D (BioSepra, Villeneuve la Garenne, France), when compared with traditional packing materials, several experiments were carried out using a commercial HPLC column, with BSA and myoglobin as test proteins. First, elution chromatographic runs under unretained conditions at several flowrates and protein concentrations were made. The HETP vs. superficial velocity plot is almost a plateau, except for the low flowrate region. Elution experiments were also carried out under weakly retained conditions (with salt concentration 0.3 M NaCl) in the linear region of the adsorption equilibrium isotherm. Using Rodrigues' equation, the experimental initial slope and plateau of a Van Deemter plot enable the determination of the effective diffusivity and Particle Permeability respectively. Then, breakthrough experiments under retaining conditions were run at several feed concentrations and flowrates. The experimental adsorption equilibrium isotherm is rectangular; using a simplified fixed-bed adsorber model for rectangular isotherms, an apparent (augmented) diffusivity is calculated as a function of flowrate. The determined augmented diffusivities are shown to follow the dependence on velocity established by Rodrigues et al.: this clearly shows that intraParticle convection is present as a mass transfer mechanism, since the real intraParticle diffusivity is independent of flowrate.
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Flow Field and Non-Isothermal Effects on Diffusion, Convection, and Reaction in Permeable Catalysts
Industrial & Engineering Chemistry Research, 1995Co-Authors: José Carlos B. Lopes, Madalena M. Dias, Vera G. Mata, Alírio E. RodriguesAbstract:We analyze non-isothermal effects on the efficiency of large-pore catalyst Particles, where intraParticle convection may be important. The Particle Permeability is taken into account by studying the flow field within the Particle simultaneously with the mass and the energy transport processes. Two Particle geometries, slab and sphere, are considered. Non-isothermal effects are observed on the occurrence of multiple steady states due to reaction ignition. It is found that, when the flow field equations are taken into account, the minimum values of the efficiency and the minimum temperatures reached inside the Particle are lower than the ones estimated considering just the mass and energy transport equations
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intraParticle diffusion convection models for pressurization and blowdown of adsorption beds with langmuir isotherm
Separation Science and Technology, 1992Co-Authors: José M. Loureiro, M.d. Levan, Alírio E. RodriguesAbstract:Abstract IntraParticle diffusion/convection and equilibrium models are used to simulate the bed dynamics of pressurization and blowdown steps of PSA processes with binary mixtures of inert and adsorbable species. The effect of the nature of the equilibrium isotherm, i.e., linear and Langmuir isotherms, is discussed. The improvement of mass transfer inside the adsorbent by increasing Particle Permeability or decreasing Particle size is addressed. Simulation results show that using “large-pore” adsorbents, i.e., increasing Permeability to cause a high intraParticle convective flow instead of decreasing Particle size to reduce intraParticle mass transfer resistances, is a good choice in PSA processes.
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INTRAParticle DIFFUSION/CONVECTION MODELS FOR PRESSURIZATION AND BLOWDOWN OF ADSORPTION BEDS WITH LANGMUIR ISOTHERM
Separation Science and Technology, 1992Co-Authors: José M. Loureiro, M.d. Levan, Alírio E. RodriguesAbstract:Abstract IntraParticle diffusion/convection and equilibrium models are used to simulate the bed dynamics of pressurization and blowdown steps of PSA processes with binary mixtures of inert and adsorbable species. The effect of the nature of the equilibrium isotherm, i.e., linear and Langmuir isotherms, is discussed. The improvement of mass transfer inside the adsorbent by increasing Particle Permeability or decreasing Particle size is addressed. Simulation results show that using “large-pore” adsorbents, i.e., increasing Permeability to cause a high intraParticle convective flow instead of decreasing Particle size to reduce intraParticle mass transfer resistances, is a good choice in PSA processes.
Patrick Patrick Anderson - One of the best experts on this subject based on the ideXlab platform.
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Effect of Particle-size dynamics on flow properties of dense spongy-Particle systems
Journal of Rheology, 2018Co-Authors: Monica E.a. Zakhari, Markus Hütter, Patrick Patrick AndersonAbstract:Suspensions of poroelastic Particles are indispensable for applications where tailoring the overall properties is a necessity. The single-Particle elastic network gives rise to their elastic behavior, while the flow of the viscous solvent through the Particle structure gives rise to their rate-dependent behavior. In this work, we study the effect of the single-Particle elastic modulus and Permeability on the properties of the entire poroelastic-Particle suspension subject to simple-shear deformation. For this purpose, the dynamic two-scale model developed by Hutter et al. [Faraday Discuss. 158, 407–424 (2012)] is used. Upon deformation, both permeable- and impermeable-Particle suspensions undergo a transition from a glassy state to a shear-induced ordered state. On the one hand, the Particle Permeability is found to affect the rate at which the ordered state is reached. At a fixed elastic modulus, increasing the Particle Permeability prolongs the time scale at which shear-induced ordering occurs. On the o...
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Stress relaxation of dense spongy-Particle systems
Journal of Rheology, 2018Co-Authors: Monica E.a. Zakhari, Markus Hütter, Patrick Patrick AndersonAbstract:Spongy Particles have a permeable structure that allows them to undergo rate-dependent volume changes as their elastic network takes up or expels the viscous suspending solvent. Their ability to be jammed well above random close-packing makes them particularly attractive in applications where tailoring the overall properties is a requirement such as pharmaceuticals and foods. In this work, we independently vary the Particle modulus and the Particle Permeability to study their effect on the stress-relaxation behavior of jammed permeable-Particle suspensions. The dynamic two-scale model developed by Hutter et al. [Faraday Discuss. 158, 407–424 (2012)], which explicitly accounts for the Particle size dynamics, is used for this purpose. We perform flow-cessation simulations of dense permeable-Particle systems subjected to different preshear deformations. The stress relaxation occurs on shorter time scales in the case of permeable Particles compared to impermeable Particles. In terms of Particle dynamics, stress relaxation is found to be promoted primarily by the motion of the Particles within the cages formed by the surrounding Particles, rather than by cage escape. The stress-relaxation process is accelerated by the Permeability of spongy Particles, namely, due to the sustained volume change that was induced during preshear, which renders their cages less effective.Spongy Particles have a permeable structure that allows them to undergo rate-dependent volume changes as their elastic network takes up or expels the viscous suspending solvent. Their ability to be jammed well above random close-packing makes them particularly attractive in applications where tailoring the overall properties is a requirement such as pharmaceuticals and foods. In this work, we independently vary the Particle modulus and the Particle Permeability to study their effect on the stress-relaxation behavior of jammed permeable-Particle suspensions. The dynamic two-scale model developed by Hutter et al. [Faraday Discuss. 158, 407–424 (2012)], which explicitly accounts for the Particle size dynamics, is used for this purpose. We perform flow-cessation simulations of dense permeable-Particle systems subjected to different preshear deformations. The stress relaxation occurs on shorter time scales in the case of permeable Particles compared to impermeable Particles. In terms of Particle dynamics, stre...
G. P. Raja Sekhar - One of the best experts on this subject based on the ideXlab platform.
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Effective viscosity of a concentrated suspension of composite porous spherical Particles
Meccanica, 2019Co-Authors: Jai Prakash, G. P. Raja SekharAbstract:We present an analytical study of the effective viscosity of concentrated suspension of porous spherical Particles with a rigid core, under the creeping flow conditions. It is assumed that the individual Particle is surrounded by a hypothetical fluid envelope. This model is popularly known as cell model, which takes into account the interaction of neighboring Particles. The flow fields inside the free flow region and porous region are governed by Stokes equation and Brinkman equation together with mass conservation, respectively. The effective viscosity of the suspension depends on various parameters such as, radii of the fluid envelope and porous Particle, Permeability of the porous Particle and further on the type of boundary condition at the outer cell, volume fraction etc. Various limiting cases are obtained and compared with earlier existing results in literature both theoretical and experimental.