The Experts below are selected from a list of 141 Experts worldwide ranked by ideXlab platform

Giuseppe Antonio Ranieri - One of the best experts on this subject based on the ideXlab platform.

  • Rheology of a lyotropic mesophase through a Stress-Relaxation Experiment.
    Journal of colloid and interface science, 2003
    Co-Authors: Luigi Coppola, Raffaella Gianferri, Cesare Oliviero, Giuseppe Antonio Ranieri
    Abstract:

    Abstract We report on the first rheological study of the structural Relaxations in a nematic liquid crystalline phase. Linear dynamic and transient shear Experiments were applied to a polydomain nematic phase of the CTAB/water system: a liquid crystalline mixture composed of 28 wt% CTAB at 35 °C. The decay of the shear modulus, G(t), was analyzed using the CONTIN inverse Laplace transform to obtain a distribution of Relaxation times which were compared with ones from the usual fitting procedure based on a generalized Maxwell model. The behavior of the nematic lyotropic structure of the CTAB/water system is characterized by the presence of both slow and fast Relaxation times. These were interpreted as being due to a progressive loss of the lyotropic domain orientation and to the breaking/reforming process of the cylindrical aggregates, respectively.

Luca Cipelletti - One of the best experts on this subject based on the ideXlab platform.

  • intrinsic aging and effective viscosity in the slow dynamics of a soft glass with tunable elasticity
    Physical Review Letters, 2005
    Co-Authors: Laurence Ramos, Luca Cipelletti
    Abstract:

    We investigate by rheology and light scattering the influence of the elastic modulus, ${G}_{0}$, on the slow dynamics and the aging of a soft glass. We show that the slow dynamics and the aging can be entirely described by the evolution of an effective viscosity, ${\ensuremath{\eta}}_{\mathrm{eff}}$, defined as the characteristic time measured in a Stress Relaxation Experiment times ${G}_{0}$. At all times, ${\ensuremath{\eta}}_{\mathrm{eff}}$ is found to be independent of ${G}_{0}$, of elastic perturbations, and of the rate at which the sample is quenched in the glassy phase. We propose a simple model that links ${\ensuremath{\eta}}_{\mathrm{eff}}$ to the internal Stress built up at the fluid-to-solid transition.

  • Intrinsic aging and effective viscosity in the slow dynamics of a soft glass with tunable elasticity
    2004
    Co-Authors: Laurence Ramos, Luca Cipelletti
    Abstract:

    We investigate by rheology and light scattering the influence of the elastic modulus, $G_0$, on the slow dynamics and the aging of a soft glass. We show that the slow dynamics and the aging can be entirely described by the evolution of an effective viscosity, $\eta_{eff}$, defined as the characteristic time measured in a Stress Relaxation Experiment times $G_0$. At all time, $\eta_{eff}$ is found to be independent of $G_0$, of elastic perturbations, and of the rate at which the sample is quenched in the glassy phase. We propose a simple model that links $\eta_{eff}$ to the internal Stress built up at the fluid-to-solid transition.

Luigi Coppola - One of the best experts on this subject based on the ideXlab platform.

  • Rheology of a lyotropic mesophase through a Stress-Relaxation Experiment.
    Journal of colloid and interface science, 2003
    Co-Authors: Luigi Coppola, Raffaella Gianferri, Cesare Oliviero, Giuseppe Antonio Ranieri
    Abstract:

    Abstract We report on the first rheological study of the structural Relaxations in a nematic liquid crystalline phase. Linear dynamic and transient shear Experiments were applied to a polydomain nematic phase of the CTAB/water system: a liquid crystalline mixture composed of 28 wt% CTAB at 35 °C. The decay of the shear modulus, G(t), was analyzed using the CONTIN inverse Laplace transform to obtain a distribution of Relaxation times which were compared with ones from the usual fitting procedure based on a generalized Maxwell model. The behavior of the nematic lyotropic structure of the CTAB/water system is characterized by the presence of both slow and fast Relaxation times. These were interpreted as being due to a progressive loss of the lyotropic domain orientation and to the breaking/reforming process of the cylindrical aggregates, respectively.

Guangyong Li - One of the best experts on this subject based on the ideXlab platform.

  • poroelasticity of cell nuclei revealed through atomic force microscopy characterization
    Applied Physics Letters, 2016
    Co-Authors: Guangyong Li
    Abstract:

    With great potential in precision medical application, cell biomechanics is rising as a hot topic in biology. Cell nucleus, as the largest component within cell, not only contributes greatly to the cell's mechanical behavior, but also serves as the most vital component within cell. However, cell nucleus' mechanics is still far from unambiguous up to now. In this paper, we attempted to characterize and evaluate the mechanical property of isolated cell nuclei using Atomic Force Microscopy with a tipless probe. As indicated from typical indentation, changing loading rate and Stress Relaxation Experiment results, cell nuclei showed significant dynamically mechanical property, i.e., time-dependent mechanics. Furthermore, through theoretical analysis, finite element simulation and Stress Relaxation Experiment, the nature of nucleus' mechanics was better described by poroelasticity, rather than viscoelasticity. Therefore, the essence of nucleus' mechanics was clarified to be poroelastic through a sophisticated a...

  • NEMS - Finite element simulation of Stress Relaxation process in living cells
    10th IEEE International Conference on Nano Micro Engineered and Molecular Systems, 2015
    Co-Authors: Peilin Zhou, Guangyong Li
    Abstract:

    In this manuscript, we investigated the fundamental mechanism of Stress Relaxation phenomenon by employing finite element simulation. Through finite element simulations, the evolution of Stress distribution, deformation field and the interaction force was wholly recorded during both the loading and Stress Relaxation stages. With the developed simulation model, the sensitivity of force-time curves on cell height and substrate stiffness was thoroughly studied by changing the thickness of cell and Young's modulus of the substrate. The simulation results indicated that the variation of cell height leads to the significant change of F-t curve's magnitude but tiny deviation of the curve's shape. And the influence originates from the substrate can be totally eliminated with relatively hard substrate. Finally, using the viscoelastic parameters extracted from actual Stress Relaxation Experiment, the dynamic mechanical behavior of L929 cells is simulated and investigated. A comparison between the Experimental and simulation F-t curves demonstrated the effectiveness of the proposed finite element simulation approach.

Laurence Ramos - One of the best experts on this subject based on the ideXlab platform.

  • intrinsic aging and effective viscosity in the slow dynamics of a soft glass with tunable elasticity
    Physical Review Letters, 2005
    Co-Authors: Laurence Ramos, Luca Cipelletti
    Abstract:

    We investigate by rheology and light scattering the influence of the elastic modulus, ${G}_{0}$, on the slow dynamics and the aging of a soft glass. We show that the slow dynamics and the aging can be entirely described by the evolution of an effective viscosity, ${\ensuremath{\eta}}_{\mathrm{eff}}$, defined as the characteristic time measured in a Stress Relaxation Experiment times ${G}_{0}$. At all times, ${\ensuremath{\eta}}_{\mathrm{eff}}$ is found to be independent of ${G}_{0}$, of elastic perturbations, and of the rate at which the sample is quenched in the glassy phase. We propose a simple model that links ${\ensuremath{\eta}}_{\mathrm{eff}}$ to the internal Stress built up at the fluid-to-solid transition.

  • Intrinsic aging and effective viscosity in the slow dynamics of a soft glass with tunable elasticity
    2004
    Co-Authors: Laurence Ramos, Luca Cipelletti
    Abstract:

    We investigate by rheology and light scattering the influence of the elastic modulus, $G_0$, on the slow dynamics and the aging of a soft glass. We show that the slow dynamics and the aging can be entirely described by the evolution of an effective viscosity, $\eta_{eff}$, defined as the characteristic time measured in a Stress Relaxation Experiment times $G_0$. At all time, $\eta_{eff}$ is found to be independent of $G_0$, of elastic perturbations, and of the rate at which the sample is quenched in the glassy phase. We propose a simple model that links $\eta_{eff}$ to the internal Stress built up at the fluid-to-solid transition.