BACKGROUND Aerospace environments commonly expose pilots to vibration and sustained acceleration, alone and in combination. CASE REPORTS Of 16 experimental research participants, 3 reported symptoms of vertigo and signs of torsional nystagmus during or shortly following exposure to sustained chest-to-spine (+3.8 Gx) acceleration (G loading) and chest-to-spine (0.5 g(x)) vibration in the 8-16 ...

Watts [1] in 1883 and Frahm [2] in 1909 reported on the first use of a dynamic vibration absorber. The range of industrial applications of such device is wide and includes the minimization of the rolling of ships, the damping of torsional vibration of internal combustion engines and the smoothing of vibrations in a barber cutter. The minimization of oscillations of tall buildings by means of dy...

Misalignment of coupled rotating machinery shafts is a frequently occurring problem which can have a substantial influence on equipment reliability. Experience has shown that diagnosis of misalignment through vibration analysis can be extremely difficult due in large part to the observed substantial variability in the character of machinery vibration even when apparently identical alignment sta...

In order to understand critical vibration of a drill bit such as stick-slip and bit-bounce and their wave propagation characteristics through a drill string system, it is critical to model the torsional, longitudinal, and flexural waves generated by the drill bit vibration. Here, a modeling method based on a vibration transfer matrix between two sets of structural wave variables at the ends of ...

Highly anisotropic microtubules (MTs) immersed in cytosol are a central part of the cytoskeleton in eukaryotic cells. The dynamic behaviors of an MT-cytosol system are of major interest in biomechanics community. Such a solid-fluid system is characterized by a Reynolds number of the order 10(-3) and a slip ionic layer formed at the MT-cytosol interface. In view of these unique features, an orth...