We describe contact-resonance atomic force microscopy ͑AFM͒ methods to quantitatively measure Poisson's ratio ␯ or shear modulus G at the same time as Young's modulus E. In contact-resonance AFM, the frequencies of the cantilever's resonant vibrations are measured while the tip is in contact with the sample. Simultaneous measurement of flexural and torsional vibrational modes enables E and ␯ to b...

A study of the combined helicopter noise and vibration problem was conducted. A refined aerodynamic model capable of calculating the unsteady surface pressure distribution on rotor blade/flap combinations is developed and coupled with an aeroelastic analysis simulation code. An acoustic prediction tool based on WOPWOP is combined with the aeroelastic analysis based on a flexible blade with coup...

Vibrations of 60 Hz and 100 Hz were applied on the mastoid of healthy subjects, patients with unilateral peripheral vestibular lesions, with central lesions of different localizations, and patients with benign paroxysmal positioning vertigo (BPPV). In patients with unilateral peripheral deficit a horizontal nystagmus with a small torsional component beating generally to the not affected side co...

Automobile components are subjected to high dynamic forces and vibrations under operational conditions which need detailed system analysis for work properly. Clutch is one of the important parts automobile powertrain with torque transmission controlling vibration damping properties. Metallic helical springs widely preferred within clutch discs their durable mechanic properties against variables...

This article proposes a control strategy to stabilize the axial–torsional dynamics of distributed drill-string system. An infinite-dimensional model for vibrational drill string is used as basis controller design. In this article, both cutting process and frictional contact effects are considered in bit–rock interaction model. Moreover, models top-side boundary conditions regarding axial torsio...

In dynamic atomic force microscopes the primary physical quantities being measured are the amplitude/phase or amplitude/frequency of the vibrating force probe. Topographic images with spatial resolutions down to the atomic scale can be obtained by mapping these measurements across the sample surface under feedback control. During the imaging process the vibrating tip is observing tip–sample int...