This article analytically investigates the interaction of pulsatile flow with peristaltic transport of a viscoelastic Maxwell fluid in a cylindrical tube. The flow is considered unsteady even in the wave frame analysis where we impose a periodic pressure gradient. This transport is studied under low Reynolds number and long wavelength approximations. The governing equations are developed up to the second-order in the Deborah number and the Womersley number. We first analyzed the impact of the pulsatile flow, of the occlusion and of the viscoelastic effects of fluid on the pressure rise and on the friction force. Physical behavior of different parameters of the problem has been graphically presented and the influence of these parameters on the mechanical efficiency has been analyzed.

No abstract

No abstract

In this paper, we investigate thermal pairwise quantum correlation for any pair of spins of a mixed-three-spin XXX Heisenberg system (with spins connected together with the nearest-neighbour (NN) and that of the next-nearest-neighbour (NNN) coupling constants J 1 and J 2 ) by means of concurrence and quantum discord, as functions of temperature T , magnetic field B and the coupling constants J 2 and J 1 . Some comparisons between these measures of entanglement are done for next-nearest-neighbour spins. We also express some magnetic properties and discuss the behaviour of the system in some special critical points. Some interesting and novel discussions are done to introduce some entanglement witnesses.

The study of MHD peristaltic transport of a Jeffrey fluid through the gap between two deformable tubes has been investigated in this paper. The outer and the inner tubes have both sinusoidal waves travelling down their walls when the amplitudes and the wavelengths are different. The equations of motion are simplified under the assumption of long wavelengths and low Reynolds number approximations. Analytical solutions for the pressure rise and axial velocity has been obtained in the closed form. Effects of pertinent parameters on pressure gradient, pressure rise, axial velocity and mechanical efficiency have been discussed through graphs. The results show that we have two cases, the first one is [Formula: see text], i.e., the wavelength of the inner tube is smaller than that of the outer tube and the second case is the opposite one [Formula: see text]. It is found that an increase of [Formula: see text] causes a decrease of the pumping and the mechanical efficiency when [Formula: see text] while an opposite behavior for [Formula: see text] is observed. In addition and for the two cases, the pumping and the mechanical efficiency increase with increasing the amplitude ration of the outer tube or the radius ratio while they decrease with the increase in the Hartmann number, amplitude ration of the inner tube or in the ratio of relaxation to retardation times.