I decompose the unstable growing modes of stellar disks to their Fourier components and present the physical mechanism of instabilities in the context of resonances. When the equilibrium distribution function is a non-uniform function of the orbital angular momentum, the capture of stars into the corotation resonance imbalances the disk angular momentum and triggers growing bar and spiral modes...

A micromachined gyroscope in which a high-speed spinning rotor is suspended electrostatically in a vacuum cavity usually functions as a dual-axis angular rate sensor. An inherent coupling error between the two sensing axes exists owing to the angular motion of the spinning rotor being controlled by a torque-rebalance loop. In this paper, a decoupling compensation method is proposed and investig...

Effect of time dependent normal transpiration on the problem of unsteady viscous flow and heat transfer in the vicinity of an axisymmetric stagnation point of an infinite circular cylinder moving simultaneously with time-depended angular and axial velocities and with time-dependent wall temperature or wall heat flux are investigated. The impinging free stream is steady with a strain rate . A re...

OBJECTIVE The purpose of this study was to compare the stability and feasibility of four fixation constructs in a posterior column acetabular fracture: one reconstruction plate, one reconstruction plate and lag screw, two reconstruction plates, and a W-shaped acetabular angular plate. METHODS Twenty embalmed cadaveric pelvises with a posterior column acetabular fractures were allocated to one...

In this paper, three controllers, including OFCHA (optimal fuzzy control using hedge algebras – HAs), FCHA (fuzzy control using HAs) and CFC (conventional fuzzy control) are designed. Attention is paid to the stability in the vertical position of a damped-elastic-jointed inverted pendulum subjected to a time-periodic follower force. The different values of the angular coefficient of the followe...

We analyze the existence and stability of two-component vector solitons in nematic liquid crystals for which one of the components carries angular momentum and describes a vortex beam. We demonstrate that the nonlocal, nonlinear response can dramatically enhance the field coupling leading to the stabilization of the vortex beam when the amplitude of the second beam exceeds some threshold value....

In this paper, a single-layer bandstop Frequency Selective Surface (FSS) is proposed for Wireless Local Area Networks (WLAN) Applications. The unit cell of the proposed FSS consists of a modification in a square patch element by the insertion of triangular shaped slots. The designs demonstrate a wide 3.8 GHz stopband in the WLAN frequency range. Moreover, it shows angular stability at various a...

We obtain, for the first time, an analytic theory of the forward stimulated Brillouin scattering instability of a spatially and temporally incoherent laser beam that controls the transition between statistical equilibrium and nonequilibrium (unstable) self-focusing regimes of beam propagation. The stability boundary may be used as a comprehensive guide for inertial confinement fusion designs. W...

In the paper, the parametric analysis of a mushroom-like and a planar metallo-dielectric periodic structure with square unit cell and metallic patch is presented. First, the angular stability for different unit cell settings was studied. Second, restrictions for simultaneous behavior as artificial magnetic conductor (AMC) and electromagnetic band gap (EBG) are briefly discussed. Finally, main d...