BACKGROUND Arterial stiffness is known to be associated with a number of clinical conditions including hypertension, diabetes and dyslipidemia, and may predict cardiovascular events and mortality. However, causal links are hard to establish. Results from genome-wide association studies have identified only a few single nucleotide polymorphisms associated with arterial stiffness, the results hav...

The interaction of work fluid mechanics with that of the rotary system itself, basically composed of axes, bearings and rotors, is performed by inserting equivalent dynamic coefficients in the mathematical model of the rotor, the latter being obtained by the finite element method. In this paper, the dynamic coefficients of inertia, stiffness and damping of the flat seals analyzed here are evalu...

Macroscopic friction coefficients observed in experiments are the result of various types of complex multiscale interactions between sliding surfaces. Therefore, there are several ways to modify them depending on the physical phenomena involved. Recently, it has been demonstrated that surface structure, e.g. artificial patterning, can be used to tune frictional properties. In this paper, we sho...

Second order linear non-autonomous differential equations with negative stiffness are considered. Using Chetaev-like (Lyapunov-like) functions, necessary (sufficient) conditions are found for the solutions to be bounded for all initial conditions if any one of the coefficients is constant. Conclusions are then extended to include systems where both coefficients are time-varying.

We evaluate the virial coefficients Bk for k ≤ 10 for hard spheres in dimensions D = 2, · · · , 8. Virial coefficients with k even are found to be negative when D ≥ 5. This provides strong evidence that the leading singularity for the virial series lies away from the positive real axis when D ≥ 5. Further analysis provides evidence that negative virial coefficients will be seen for some k > 10 ...

This paper addresses the problem of task-based stiffness synthesis of a variable geometry three DOF (Degrees Of Freedom) planar robot. The synthesis considers the case where the robot has a limited number of free geometric parameters and constant actuator stiffness coefficients. This defines twenty problems of stiffness synthesis, in which, three parameters of the stiffness matrix are controlle...

The forced frequency analysis is very important in the design of automotive structures. In particular, the Frequency Response Functions (FRF) computation is an important step in determining Noise, Vibration and Harshness (NVH) of any automotive vehicle. In general, the CAE engineer must address the severity and compliance of the design limits set in the NVH environment. Usually, a CAE engineer ...

This paper gives a qualitative description how Young tableaux can be used to perform a Clebsch-Gordan decomposition of tensor products in SU(3) and how this can be generalized to SU(N).

This essay describes the development of groups used for the specification of symmetries from ordinary and magnetic point groups to Fedorov and magnetic space groups, as well as other varieties of groups useful in the study of symmetric objects. In particular, we consider the problem of some incorrectness in Vol. A of the International Tables for Crystallography. Some results of tensor calculus ...

Interest in vibration control in systems employing rolling element bearings, ranging from rotor systems used in energy conversion/transmission to high-precision, multi-degree-offreedom optical positioning systems, has focused attention on the modelling of bearing dynamic stiffness properties. While modelling a rolling element bearing either as an ideal boundary condition for a shaft or as a sim...