This study characterizes tonic and phasic stretch reflex and stiffness and viscosity changes associated with spastic hemiparesis. Perturbations were applied to the ankle of 27 hemiparetic and 36 healthy subjects under relaxed or active contracting conditions. A nonlinear delay differential equation model characterized phasic and tonic stretch reflex gains, elastic stiffness, and viscous damping...

We examine the role of Alfvén wave damping in heating the plasma in the magnetic funnels of magnetospheric accretion models of young stars. We study four different damping mechanisms of the Alfvén waves: nonlinear, turbulent, viscous-resistive and collisional. Two different possible origins for the Alfvén waves are discussed: 1) Alfvén waves generated at the surface of the star by the shock pro...

In this study, the damping mechanism at the interface of the mating spur gear teeth is investigated. The dynamic behaviour of a spur gear pair is represented by a two Degree-of-Freedom (DOF) nonlinear model with the damping provided by the instantaneous tribological behaviour of the tooth contacts. The shear stress distributions along the tooth surfaces are incorporated with the dynamic model t...

We consider viscous damping of both strong and weak Alfvenic turbulence in fully ionized plasmas. We find that the damping is affected by the wandering of magnetic field lines, which makes the effective viscosity scale-dependent. We show that the strong turbulence cascade gets into the viscosity-damped regime at the scale that is larger than the ion mean free path by a ratio of thermal to Alfve...

Parametric identification of viscous damping models in the context of linear vibration theory is studied. Frequency domain identification methods based on measured frequency response functions (FRFs) are considered. Existing methods are classified into two main groups: matrix methods which use directly the measured FRF matrix, and modal methods which use modal parameters deduced from the FRFs. ...

Damping is the conversion of mechanical energy of a structure into thermal energy, and it is related to the material viscous behavior. To evaluate the role of damping in the common carotid artery (CCA) wall in human hypertension and the possible improvement of angiotensin-converting enzyme (ACE) inhibition, we used noninvasive CCA pressure (tonometry) and diameter (B-mode echography) waveforms ...

BACKGROUND The purpose of this study was to determine whether changes in the constitutive properties of the cardiac muscle cell play a causative role in the development of diastolic dysfunction. METHODS AND RESULTS Cardiocytes from normal and pressure-hypertrophied cats were embedded in an agarose gel, placed on a stretching device, and subjected to a change in stress (sigma), and resultant c...

Several design methods aimed at sizing the viscous dampers to be inserted in building structures have been proposed in the last decades. Among others, the authors proposed a five-step procedure that guides the practical design from the choice of a target reduction in the seismic response of the structural system (with respect to the response of a structure without any additional damping devices...