Figure rotation substantially increases the fraction of stochastic orbits in triaxial systems. This increase is most dramatic in systems with shallow cusps showing that it is not a direct consequence of scattering by a central density cusp or black hole. In a recent study of stationary triaxial potentials (Valluri & Merritt 1998) it was found that the most important elements that define the str...

Context. Over the last decade a series of results have lent support to the hypothesis of the existence of a long thin bar in the Milky Way with a half-length of 4.5 kpc and a position angle of around 45◦. This is apparently a very different structure from the triaxial bulge of the Galaxy. Aims. In this paper, we analyse the stellar distribution in the inner 4 kpc of the Galaxy to see if there i...

The radial-orbit instability is a collective phenomenon that has heretofore only been observed in spherical systems. We find that this instability occurs also in triaxial systems, as we checked by performing extensive N -body simulations whose initial conditions were obtained by sampling a self-consistent triaxial model of a cuspy galaxy composed of luminous and dark matter. N -body simulations...

We study the behaviors of galactic disks in triaxial halos both numerically and analytically to see if warps can be excited and sustained in triaxial potentials. We consider the following two scenarios: 1) galactic disks that are initially tilted relative to the equatorial plane of the halo (for a pedagogical purpose), and 2) tilted infall of dark matter relative to the equatorial plane of the ...

While there have been many discrete element method (DEM) publications considering the micromechanics of granular materials subject to monotonic loading, studies of the particle-scale material response to cyclic or repeated loading have been comparatively rare. From a geotechnical perspective soil is subjected to repeated loading in a variety of situations. Examples include foundations to railwa...

A comprehensive experimental study that quantifies the influence of coupled compression and shear wave loading on liquefaction susceptibility sands is presented. Such typical in situ, leads to complex principal stress rotation, which turn impacts potential for soils even if cyclic intensity remains constant. The nature degree rotation caused by this are significantly influenced initial consolid...

This talk provides a progress report on an extended collaboration which has aimed to address two basic questions, namely: Should one expect to see cuspy, triaxial galaxies in nature? And can one construct realistic cuspy, triaxial equilibrium models that are robust? Three technical results are described: (1) Unperturbed chaotic orbits in cuspy triaxial potentials can be extraordinarily sticky, ...

The Jeans equations relate the second-order velocity moments to the density and potential of a stellar system. For general three-dimensional stellar systems, there are three equations and six independent moments. By assuming that the potential is triaxial and of separable Stäckel form, the mixed moments vanish in confocal ellipsoidal coordinates. Consequently, the three Jeans equations and thre...

Firstly, we demonstrate that unusually large outer HI spiral arms observed in NGC 2915 can form in an extended gas disk embedded in a massive triaxial dark matter halo with slow figure rotation, through the strong gravitational torque of the rotating halo. Secondly, we show that the figure rotation of a triaxial dark matter halo can influence dynamical evolution of disk galaxies by using fully ...

Typical vibration monitoring systems for helicopter gearboxes rely on single-axis accelerometer data. This paper investigates whether triaxial accelerometers can provide crucial flight regime information for helicopter gearbox monitoring systems. The frequency content of the three different directions is compared and analyzed using time-synchronously averaged vibration data. The triaxial data a...