The paper deals with design, modelling, and testing of an ultrasonic (US) chain torsional vibrations that includes a tool at its end could be used for different industrial applications such conventional nonconventional machining revolution, helicoidal, curved surfaces or various types materials. US horn helicoidal channel whose profile was studied aiming growing the amplification amplitude tool...

For a simply supported Bernoulli-Euler beam under moving load with constant velocity the bending and torsion vibrations are analysed. An analytical solution of decoupled partial differential equations is derived based on eigenmode expansion considering boundary initial conditions. pure analysis performed calculated. various longitudinal speeds results plotted. The coupled deformations computed ...

The interest in using delayed designs is emphasized recent research on the stabilization of finite/infinite dimensional dynamical systems. A property called multiplicity-induced-dominancy (or MID for short) allows a reduced-complexity delayed- controller design showed its efficiency fast damping harmful oscillations. This contribution concerned with oil-well drilling systems torsional vibration...

We obtained the electronic spectra of various methylated xanthine compounds including caffeine in a supersonic jet by resonant two-photon ionization spectroscopy. The methyl group in the tested methylated xanthine compounds has a distinct, site-dependent effect on the electronic spectrum. Methylation at the N3 position causes a significant red shift of the ππ* state, whereas methylation at the ...

In this paper, two kinds of vibrations are considered for a composite Timoshenko rotor: longitudinal-torsional vibration and two plane transverse one. The kinetic and potential energies and virtual work due to the gyroscopic effects are calculated and the set of six governing equations and boundary conditions are derived using Hamilton principle. Differential quadrature method (DQM) is used as ...

In this paper, we consider linear dynamics subject to a distributed state-dependent delay and a pointwise input-delay. We propose a prediction-based controller which exponentially stabilizes the plant. The controller design is based on a backstepping approach where delays are reformulated as hyperbolic transport PDEs. Infinity-norm stability analysis of the corresponding closed-loop system is a...

Low-frequency Raman spectra of the porous structure formed on C-implanted silicon were examined using the 514.5 and 488 nm lines of Ar laser. The sharp low-frequency Raman peaks were observed with narrow linewidth and large intensity. According to usual vibration theory of the elastic body and related symmetry analysis, they are identified as the localized acoustic phonon torsional modes result...