Unbalance and misalignment are the commonly occurring faults in rotating mechanical systems. These faults are caused mainly due to improper installation or premature failure of the machine components. Detection and diagnosis of faults in rotating machinery is crucial for its optimal performance. In this study artificial neural networks (ANN) and support vector machine (SVM) techniques have been...

Computer N -body experiments are desribed which test the validities of the original Toomre’s (1964) criterion and of a generalized criterion for local stability of Jeans-type perturbations in a self-gravitating, infinitesimally thin, and practically collisionless disk of stars. The fact that the nonaxisymmetric perturbations in the differentially rotating system are more unstable than the axisy...

Motivated by observations of disk galaxies with counter-rotating stars, we have run two-dimensional, collisionless N−body simulations of disk galaxies with significant counter-rotating components. For all our simulations the initial value of Toomre’s stability parameter was Q = 1.1. The percentage of counter-rotating particles ranges from 25% to 50%. A stationary one-arm spiral wave is observed...

A new type of Acoustic Emission sensor using a thin film piezoelectric material (sputtered ZnO) was developed for measuring head-disk interaction in a rigid magnetic disk system. The sensor is mounted on a Si slider (length : 3 mm) and was fabricated using micro-machining techniques in our on-going efforts to downsize sliders. Some fundamental tests of the sensor were conducted : sensitivity an...

Observations were made that falsify planetary formation via proto-planetary disk. An alternative model is proposed. Observations that Falsify the Proto-planetary Disk/Nebular Hypothesis Model: 1. Older stars are still mislabeled by mainstream as planets/exo-planets. [1] They orbit the opposite direction their host star is rotating. [2] The backwards orbits completely falsifies any notion of a c...

A liquid membrane disk electrode, LMDE, and a liquid membrane ring-liquid membrane disk electrode, LMRE-LMDE, were developed by placing a gelled polyvinyl chloride thin membrane impregnated with 2-nitrophenyl octyl ether, NPOE-LM, on the surface of a glassy carbon, GC, disk or ring electrode. The voltammogram for the ion transfer at the interface between an aqueous solution, W, and NPOE-LM was ...

Micrometer-sized reflection holograms can be written into a rapidly rotating homogeneous photopolymer disk at the focus of a high-numerical-aperture beam and its retroreflection to implement high-capacity multilayer digital data storage. This retroreflection is generated by an optical system with positive unity magnification to ensure passive alignment of the counterpropagating beam. Analysis r...

We study the space geometry of a rotating disk both from a theoretical and operational approach, in particular we give a precise definition of the space of the disk, which is not clearly defined in the literature. To this end we define an extended 3-space, which we call relative space: it is recognized as the only space having an actual physical meaning from an operational point of view, and it...

Misaligned accretion disks surrounding rotating compact objects experience a torque due to the LenseThirring effect, which leads to precession of the inner disk. It has been suggested that this effect could be responsible for some low frequency Quasi-Periodic Oscillations observed in the X-ray lightcurves of neutron star and galactic black hole systems. We investigate this possibility via time-...