Although the effect of temporal pressure on spatio-temporal aspects of motor coordination and posture is well established in young adults, there is a clear lack of data on elderly subjects. This work examined the aging-related effects of temporal pressure on movement synchronization and dynamic stability. Sixteen young and eleven elderly subjects performed series of simultaneous rapid leg flexi...

Falling paper flutters and tumbles through air, whereas a airplane glides smoothly if its leading edge is appropriately weighted. We investigate this transformation from ‘plain paper’ to ‘paper plane’ experiments, aerodynamic modelling free flight simulations of thin plates with differing centre mass (CoM) locations. Periodic modes such as fluttering, tumbling bounding give way steady gliding t...

A spatial parallel mechanism namely 3-RRS mechanism has been assigned to be attached to the seat of a standard electric wheelchair to prevent the turning over of the handicapped sitting on the wheelchair. The system of the wheelchair and the mechanism is a self-balancing robotic wheelchair and has coped with several road conditions. A stability control system calculates the proper moments on th...

We have investigated the possibility of extending the stability range of the biaxial nematic phase by adding an off-centre dipole of various strengths and orientations to elongated biaxial Gay-Berne (GB) mesogens yielding a relatively narrow biaxial nematic (Nbx) phase, and a smectic (Sbx) phase when dipole-less. The effect of dipoles is not easy to predict, and our previous investigations have...

We consider a ring of identical elements with time delayed, nearest neighbour coupling. The individual elements are modelled by a scalar delay differential equation which includes linear decay and nonlinear delayed feedback. The linear stability of the trivial solution is completely analyzed and illustrated in the parameter space of the coupling strength and the coupling delay. Conditions for g...

Functional stability limits (FSLs) are the percentage of the base of support that individuals are willing to extend their centre of pressure. The objective of this study was to provide construct validation of FSLs as a measure of balance by comparing FSLs across ages and with clinical balance measures. A total of 52 participants volunteered. FSLs significantly decreased with age (p < 0.004). Co...

We investigate the Lyapunov stability of the stationary solutions of the differential equations of restricted six-body problem with the gravitational centre. The gravitational field is created by bodies P0, P1, P2, P3 and P4 with masses m0, m1, m2, m3 and m4, respectively. In this gravitational field the movement of a body P with zero mass (m = 0) is investigated. The bodies P1, P2, P3 and P4 f...

This paper deals with the stability of triangular Lagrangian points in the elliptical restricted three body problem, under the effect of radiation pressure stemming from the more massive primary on the infinitesimal. We adopted a set of rotating pulsating axes centered at the centre of mass of the two primaries Sun and Jupiter. We have exploited method of averaging used by Grebenikov, throughou...

In this paper we prove the stability of the zero equilibria of two systems of difference equations of exponential type, which are some extensions of an one-dimensional biological model. The stability of these systems is investigated in the special case when one of the eigenvalues is equal to -1 and the other eigenvalue has absolute value less than 1, using centre manifold theory. In addition, w...

In this paper, we consider a discrete Gompertz model with time delay. Firstly, the stability of the equilibrium of the system is investigated by analyzing the characteristic equation. By choosing the time delay as a bifurcation parameter, we prove that NeimarkSacker bifurcations occur when the delay passes a sequence of critical values. The direction and stability of the Neimark-Sacker are dete...