Magnetohydrodynamic Peristaltic flow of a couple stress with heat and mass transfer of a Jeffery fluid in a tube through porous medium
The effects couple stress on the unsteady flow of a couple stress fluid an incompressible non-Newtonian (Jeffrey) fluid through porous medium have been discussed. The thermal diffusion thermo effect are taken to our consideration. Analytical expression for the axial velocity, stream function and axial pressure gradient are established. The flow is investigated in a wave frame of reference moving with the velocity of the wave. The non-linear partial differential equations which govern this problem are simplified by making the assumptions of long wave length approximation. The analytical formula of the velocity and temperature have been obtained in terms of Bessel function of first and second kinds. In addition, it has been illustrated graphically for significant various parameters such as, magnetic parameter, couple stress parameter, permeability parameter, and thermal parameters .
Magnetohydrodynamics Peristaltic Flow of a Couple- Stress for a Jeffrey Fluid through a Flexible Porous Medium
The topic of this paper is the peristaltic motion of a non-Newtonian Jeffrey fluid with couple stress across a porous medium inside a horizontal conduit. The unit is strained by a uniform magnetic field. It is taken into account the effects of viscous dissipation, internal heat generation, and radiation. This approach solves the equations of momentum, temperature, and velocity. The numerical formulas for axial velocity, temperature, and velocity are obtained as functions of the physical parameters of the problem. Numerical calculations, as well as the effects of temperature and magnetic field on the velocity equation, were conducted for this formula, and the results were shown on the channel wall. The results of the problem’s physical parameters on this formula are discussed numerically and graphically in a series of statistics.
Police and Political Violence in the 1960s and 1970s: Germany and Italy in a Comparative Perspective
Notwithstanding the significant differences between the German and Italian police models (federal and civil vs. centralised and militarised), in both countries the confrontation with the protest movements of the 1960s and 1970s had a profound impact on police conceptions and public order strategies. Police forces in some German federal states (West Berlin) followed a hard line until the late 1960s, while in others (Munich, Hamburg) reforms to the Weimar-centred police intervention tactics took place beginning in the early to mid-1960s. In Italy, traditional police conceptions and strategies remained largely unchanged and re-emerged in 1968. Here, a movement from within the police led to the demilitarisation and unionisation of the state police in 1981. In both countries, fighting left-wing terrorism in the 1970s stimulated technical modernisation and enhanced the centralisation of the police. In critical response to police tactics, in the late 1970s Germany police matters were increasingly perceived as a concern not only of the state but of civil society—even if policing remained a highly contested terrain. In Italy, such matters largely remained state concerns in which only politicians and internal security specialists were entitled to intervene.