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Marie-agnès Peyron - One of the best experts on this subject based on the ideXlab platform.

  • effect of texture of plastic and Elastic Model foods on the parameters of mastication
    Journal of Neurophysiology, 2006
    Co-Authors: K D Foster, Alain Woda, Marie-agnès Peyron
    Abstract:

    Mastication is continually modified throughout the chewing sequence in response to the texture of the food. The aim of this work was to compare the effects of an increase in hardness of two Model f...

  • Effects of increased hardness on jaw movement and muscle activity during chewing of visco-Elastic Model foods
    Experimental Brain Research, 2002
    Co-Authors: Marie-agnès Peyron, C. Lassauzay, Alain Woda
    Abstract:

    When food is chewed, sensory feedback adapts the motor program to the characteristics of the food. However, the relationship between the physical properties of different foods and the motor response is poorly understood. In this study, we developed edible and well-controlled Model foods in order to describe some of the stimulus-response functions of the food-mastication loop. Four gelatine-based visco-Elastic Model foods identical in shape and size but differing in hardness were prepared. They displayed reproducible sensory and physical characteristics and were distributed on a wide hardness scale. Electromyographic activity of masseter and temporalis muscles and jaw movements in the frontal plane were simultaneously recorded during mastication in 15 young men with intact dentition and good oral status. Almost all EMG and jaw movement parameters were clearly affected by increasing hardness of Model foods. However, it is possible to summarise the results by reducing the number of parameters to three: the number of chewing cycles, EMG activity of any one of the two temporal or the two masseter muscles and the amplitude of the opening mandibular movements. Indeed, these were the best transcriptors of the hardness range of the Model foods used in this study. As inferred from these parameter recordings, the food hardness modifications were strongest during the first five strokes, began as early as the first stroke and lasted for the whole sequence.

  • Variability of the masticatory process during chewing of Elastic Model foods
    European Journal of Oral Sciences, 2000
    Co-Authors: C. Lassauzay, Marie-agnès Peyron, Eliane Albuisson, Eric Dransfield, A. Woda
    Abstract:

    : Many studies show a consistent individual chewing pattern; chewing being governed by a pattern generator and regulated by sensory feedback. The aim of this study was to determine the variation in chewing between sessions, replicates and subjects using Elastic Model foods. Fifteen young male subjects were selected to chew four food products differing in hardness. Four sessions were performed at 1-wk intervals for each subject and, within each session, the four Model foods were presented 3 times each. Jaw movement was recorded simultaneously with masseter and anterior temporalis electromyographic activities. Several chewing characteristics increased progressively from one session to the next; the largest increase occurred from the 1st to the 2nd session, with little difference between the last two sessions. No differences were observed between the samples of the same food product within a session. As mastication progressed, the amplitude and speed of the cycles and the muscular work decreased progressively. The first cycle appeared to be very different from the subsequent for all parameters except for occlusal duration. Thus, under our experimental conditions, the origin and amount of variation in chewing patterns were identified and provide information to improve the accuracy and comparability of results in studies of mastication.

Alain Woda - One of the best experts on this subject based on the ideXlab platform.

  • effect of texture of plastic and Elastic Model foods on the parameters of mastication
    Journal of Neurophysiology, 2006
    Co-Authors: K D Foster, Alain Woda, Marie-agnès Peyron
    Abstract:

    Mastication is continually modified throughout the chewing sequence in response to the texture of the food. The aim of this work was to compare the effects of an increase in hardness of two Model f...

  • Effects of increased hardness on jaw movement and muscle activity during chewing of visco-Elastic Model foods
    Experimental Brain Research, 2002
    Co-Authors: Marie-agnès Peyron, C. Lassauzay, Alain Woda
    Abstract:

    When food is chewed, sensory feedback adapts the motor program to the characteristics of the food. However, the relationship between the physical properties of different foods and the motor response is poorly understood. In this study, we developed edible and well-controlled Model foods in order to describe some of the stimulus-response functions of the food-mastication loop. Four gelatine-based visco-Elastic Model foods identical in shape and size but differing in hardness were prepared. They displayed reproducible sensory and physical characteristics and were distributed on a wide hardness scale. Electromyographic activity of masseter and temporalis muscles and jaw movements in the frontal plane were simultaneously recorded during mastication in 15 young men with intact dentition and good oral status. Almost all EMG and jaw movement parameters were clearly affected by increasing hardness of Model foods. However, it is possible to summarise the results by reducing the number of parameters to three: the number of chewing cycles, EMG activity of any one of the two temporal or the two masseter muscles and the amplitude of the opening mandibular movements. Indeed, these were the best transcriptors of the hardness range of the Model foods used in this study. As inferred from these parameter recordings, the food hardness modifications were strongest during the first five strokes, began as early as the first stroke and lasted for the whole sequence.

J Klafter - One of the best experts on this subject based on the ideXlab platform.

  • generalized Elastic Model fractional langevin description fluctuation relation and linear response
    arXiv: Statistical Mechanics, 2013
    Co-Authors: Alessandro Taloni, Aleksei V Chechkin, J Klafter
    Abstract:

    The Generalized Elastic Model is a linear stochastic Model which accounts for the behaviour of many physical systems in nature, ranging from polymeric chains to single-file systems. If an external perturbation is exerted \emph{only} on a single point $\vec{x}^\star$ (\emph{tagged probe}), it propagates throughout the entire system. Within the fractional Langevin equation framework, we study the effect of such a perturbation, in cases of a constant force applied. We report most of the results arising from our previous analysis and, in the present work, we show that the Fox $H$-functions formalism provides a compact, elegant and useful tool for the study of the scaling properties of any observable. In particular we show how the generalized Kubo fluctuation relations can be expressed in terms of $H$-functions.

  • generalized Elastic Model fractional langevin description fluctuation relation and linear response
    Mathematical Modelling of Natural Phenomena, 2013
    Co-Authors: Alessandro Taloni, Aleksei V Chechkin, J Klafter
    Abstract:

    The Generalized Elastic Model is a linear stochastic Model which accounts for the behaviour of many physical systems in nature, ranging from polymeric chains to single-file systems. If an external perturbation is exerted only on a single point x ⋆ (tagged probe ), it propagates throughout the entire system. Within the fractional Langevin equation framework, we study the effect of such a perturbation, in cases of a constant force applied. We report most of the results arising from our previous analysis and, in the present work, we show that the Fox H -functions formalism provides a compact, elegant and useful tool for the study of the scaling properties of any observable. In particular we show how the generalized Kubo fluctuation relations can be expressed in terms of H -functions.

  • generalized Elastic Model yields a fractional langevin equation description
    Physical Review Letters, 2010
    Co-Authors: Alessandro Taloni, Aleksei V Chechkin, J Klafter
    Abstract:

    Starting from a generalized Elastic Model which accounts for the stochastic motion of several physical systems such as membranes, (semi)flexible polymers, and fluctuating interfaces among others, we derive the fractional Langevin equation (FLE) for a probe particle in such systems, in the case of thermal initial conditions. We show that this FLE is the only one fulfilling the fluctuation-dissipation relation within a new family of fractional Brownian motion equations. The FLE for the time-dependent fluctuations of the donor-acceptor distance in a protein is shown to be recovered. When the system starts from nonthermal conditions, the corresponding FLE, which does not fulfill the fluctuation-dissipation relation, is derived.

D.z. Sun - One of the best experts on this subject based on the ideXlab platform.

  • Pseudo-Elastic description of polymeric foams at finite deformation with stress softening and residual strain effects
    Materials & Design, 2011
    Co-Authors: X.f. Zhang, F. Andrieux, D.z. Sun
    Abstract:

    Abstract Polymeric foams are typical materials for energy absorber in such areas as aircraft, car industry and in the field of electronic packaging. Besides the typical hyperElastic behaviour, non-linear stress–strain behaviour in large Elastic deformation, polymeric foams may also exhibit some inElastic effects, like stress softening and residual strain. In this paper we first describe some experiment results that illustrate the stress softening in compressible expanded polypropylene (EPP) foams together with associated residual strain effects. Then, based on Ogden and Dorfmann’s results, a pseudo-Elastic Model is introduced to capture the stress softening and residual strain effects by including of two variables in the energy function. Numerical simulations of uniaxial-compression tests of two types of EPP foam are used to determine the material parameters of Ogden’s Model, stress softening and residual strain effects. The numerical simulations indicate that the pseudo-Elastic Model provides reasonably accurate predictions of the inElastic behaviour of polymeric foam.

Page, Ana M. - One of the best experts on this subject based on the ideXlab platform.

  • Fatigue sensitivity to foundation Modelling in different operational states for the DTU 10MW monopile-based offshore wind turbine
    'IOP Publishing', 2019
    Co-Authors: Katsikogiannis George, Achynski, Eri Elizabeth, Page, Ana M.
    Abstract:

    The importance of foundation Modelling for the support-structure fatigue damage estimation of a 10 MW monopile based offshore wind turbine is investigated in different operational states and wind-wave misalignment conditions. Three different Models are used: (1) a non-linear elasto-plastic Model including hysteretic behaviour effects, (2) a linear Elastic Model and (3) a non-linear Elastic Model, using numerical simulations with an aero-hydro-servo-Elastic computational tool. Depending on the environmental condition, different dynamic processes dominate the responses. For parked states, deviations between Models up to 160% were found. For wind wave-misalignment over 30° in operational cases, differences up to 180% were found for low sea states and 119% for high sea sates. Both nonlinear foundation damping and stiffness formulation have considerable effect on the responses, with hysteretic effects becoming crucial when aerodynamic damping is negligible in the direction of the response. Attention is required when comparing the fatigue damage only at the mudline, as larger variations between the Models may occur in the embedded part of the monopile, where the absolute maximum is found.Fatigue sensitivity to foundation Modelling in different operational states for the DTU 10MW monopile-based offshore wind turbinepublishedVersio