Introduction MRI acoustic noise represents a possible hazard to patients and volunteers undergoing scanning and to workers present in the scanner room during imaging. Vibrations in the gradient coils are generated by Lorentz forces, induced by the currents flowing through the gradient coils within the static magnetic field. The vibrations are transmitted to other parts of the scanner and finall...

Self-excited vibrations are observed in many technical applications. Frictional contacts are often involved in the mechanism which generates vibrations. Reasons for the excitation mechanisms are decreasing friction characteristics depending on the sliding velocity, fluctuating normal loads or different geometrical effects. First, the mechanisms are explained using simple examples. The practical...

In humans and other vertebrates, hearing is improved by active contractile properties of hair cells. Comparable active auditory mechanics is now demonstrated in insects. In mosquitoes, Johnston's organ transduces sound-induced vibrations of the antennal flagellum. A non-muscular 'motor' activity enhances the sensitivity and tuning of the flagellar mechanical response in physiologically intact a...

The periodic wake flow past a bluff body immersed in moving fluid can be synchronized to the harmonic vibrations of body. A low-dimensional, phase-based analysis has been adopted uncover theoretical conditions necessary for synchronization between and oscillations. present methodology allows modifying transient features unsteady flows, thereby enabling online control aerodynamic forces on flyer...

This article presents results of ground motion and magnet vibrations measurements at the Advanced Photon Source. The experiments were done over a wide frequency range (0.05-100 Hz) with the use of SM-3KV-type seismic probes from the Budker Institute of Nuclear Physics (Russia). Spectral power densities of vertical and horizontal motions of the APS hall floor and quadrupoles on regular supports ...

The Compact LInear Collider (CLIC), presently under study at the European Organization for Nuclear Research (CERN), aims at colliding high-energy “nanobeams” at a luminosity of 10 cm−2s−1. Vibrations of the lattice elements, if not properly corrected, can result in a loss in performance by creating both unacceptable emittance growth in the linear accelerator and relative beam-beam offsets at th...