the cadaver spine motion segment behavior under torsional load was evaluated with the disc intact, with partial anterior discectomy and with spacer insertion. the results of this study explain how anterior lumbar discectomy and interbody fusion (alif) affects the torsional stability of the motion segment. the pseudarthrosis rate of the anterior lumbar discectomy and interbody fusion (alif) is k...

Flexural wave speeds on beams or plates depend upon the bending stiffnesses which differ by the well-known factor (1 - nu2). A quantitative analysis of a plate of finite lateral width displays the plate-to-beam transition, and permits asymptotic analysis that shows the leading order dependence on the width. Orthotropic plates are analyzed using both the Kirchhoff and Kirchhoff-Rayleigh theories...

We present examples of phononic structures that beak four types of symmetry, namely timereversal symmetry, parity symmetry, chiral symmetry and particle-hole symmetry. The implications of symmetry breaking on the topology of the acoustic wave function in the space of its Eigen values are discussed. Particular attention is focused on the torsional topology of acoustic waves in periodic media in ...

Torsional Alfven waves are likely excited with bursts in rotating magnetars. These waves are probably propagated through corotating atmospheres toward a vacuum exterior. We have studied the physical effects of the azimuthal wave number and the characteristic height of the plasma medium on wave transmission. In this work, explicit calculations were carried out based on the three-layered cylindri...

We exhibit all spatially isotropic homogeneous Galilean spacetimes of dimension $(n+1) \geq 4$, including the novel torsional ones, as null reductions pp-wave spacetimes. also show that pp-waves are sourced by pure radiation fields and analyse their global properties.

In this paper, the propagation of time-harmonic torsional waves in composite elastic cylinders is investigated. An imperfect interface is considered where tractions are continuous across the interface and the displacement jump is proportional to the stress acting on the interface. A frequency equation is derived for the rod and dispersion curves of normalized frequency as a function of normaliz...