We present two continuum models A and B to study the convective instability of granular materials subjected to vibrations. We carry out the linear stability analysis for model A and uncover the instability mechanism as a supercritical bifurcation of a bouncing solution. We also explicitly determine the onset of convection as a function of control parameters. The simulations results are in excel...

In this paper, the global dynamic behaviors of an SEIQS epidemic system with a nonlinear incidence rate are investigated. At first, the stabilities of equilibria for the system are analyzed. Thus, the codimension-1 bifurcations including transcritical bifurcation, saddle-node bifurcation, Hopf bifurcation are discussed using bifurcation theory. In particular, codimension2 bifurcation (Bogdanov-...

In turbulent rotating Rayleigh-Bénard convection Ekman vortices extract hot or cold fluid from thermal boundary layers near the bottom or top plate and enhance the Nusselt number. It is known from experiments and direct numerical simulation on cylindrical samples with aspect ratio Γ ≡ D/L (D is the diameter and L the height) that the enhancement occurs only above a bifurcation point at a critic...

The dynamics of inertial elastic helical thin rods with noncircular cross sections and arbitrary intrinsic curvature, torsion, and twist is studied. The classical Kirchhoff equations are used together with a perturbation scheme at the level of the director basis, and the dispersion relation for helical strips is derived and analyzed. It is shown that all naturally straight helical strips are un...

An investigation is carried out on the systematic analysis of the dynamic behavior of the hybrid squeeze-film damper HSFD mounted a rotor-bearing system with strongly nonlinear oil-film force and nonlinear rub-impact force in the present study. The dynamic orbits of the system are observed using bifurcation diagrams plotted using the dimensionless rotating speed ratio as control parameters. The...

In this paper, we study the persistence, stability and Hopf bifurcation in a ratio-dependent predator–prey model with diffusion and delay. Sufficient conditions independent of diffusion and delay are obtained for the persistence of the system and global stability of the boundary equilibrium. The local stability of the positive constant equilibrium and delay-induced Hopf bifurcation are investig...

We study reaction dynamics on a model potential energy surface exhibiting post-transition state bifurcation in the vicinity of a valley ridge inflection (VRI) point. We compute fractional yields of products reached after the VRI region is traversed, both with and without dissipation. It is found that apparently minor variations in the potential lead to significant changes in the reaction dynami...

Bifurcation control deals with modification of bifurcation characteristics of a parameterized nonlinear system by a designed control input. Typical bifurcation control objectives include delaying the onset of an inherent bifurcation, stabilizing a bifurcated solution or branch, changing the parameter value of an existing bifurcation point, modifying the shape or type of a bifurcation chain, int...

OBJECTIVES To compare endovascular coiling with neurosurgical clipping of ruptured basilar bifurcation aneurysms. METHODS Patient and aneurysm characteristics, procedural complications, and clinical and anatomical results were compared retrospectively in 44 coiled patients and 44 patients treated by clipping. The odds ratios for poor outcome (Glasgow outcome scale 1, 2, 3) adjusted for age, c...