BACKGROUND Ultrasonic motors (USM) are based on the concept of driving the rotor by a mechanical vibration excited on the stator via piezoelectric effect. USM exhibit merits such as simple structure, quick response, quiet operation, self-locking when power off, nonelectromagnetic radiation and higher position accuracy. PRINCIPAL FINDINGS A cylindrical type traveling wave ultrasonic motor usin...

Discuss the scattering of a plane electromagnetic wave of angular frequency ω that is normally incident on a perfectly conducting cylinder of radius a (in vacuum) when the wavelength obeys λ a (ka 1). Comment also on the limit of large cylinders, ka 1, via the optical theorem. Extend the discussion to the case of small conducting elliptical cylinders, which have (small) flat strips as a limit. ...

A numerical study of the natural convection of the laminar heat transfers in the stationary state was developed in a horizontal ring and compared between a heated trapezoidal internal cylinder and a cold elliptical outer cylinder. This annular space is traversed by a Newtonian and incompressible fluid. The Prandtl number is set to 0.7 (air case) for different Rayleigh numbers. The system of equ...

The spatial organization of single-fluid Marangoni convection in vertical cylinders with circular and elliptical horizontal cross-section is described. The convection is driven by an imposed heat flux from above and driven by Marangoni stresses at a free but undeformed surface due to temperature-dependent surface tension. The solutions and their stability characteristics are obtained using bran...

The article describes the developed algorithm for calculating strength parameters of a thin shell in form an elliptical cylinder, taking into account shear deformations geometrically nonlinear setting. numerical finite element method (FEM) was used as research tool. An formation stiffness matrix and column nodal forces at loading step using two versions interpolation procedure. In first version...

In this paper, flow over an elliptical cylinder located near a moving wall is investigated numerically to ascertain the effect of aspect ratio (AR) on characteristics in terms wake pattern, separation and stagnation points, hydrodynamic forces. The two-dimensional simulations span both steady unsteady regimes, where AR analyzed conjunction with other important parameters, such as gap (GR∈ [0.6,...