Nonlinear dynamic model of the coupled lateral-torsional vibrations of a gear transmission system is developed, in which time-varying gear meshing stiffness, errors, and gaps are considered. The fundamental rules of the system’s multi-harmonic dynamic response have been obtained based on the time domain diagram, frequency domain diagram, phase plot, and Poincaré map. Therefore, estimation of th...

One of the signs of the cerebellar ocular motor syndrome is the inability to maintain horizontal and vertical fixation. Typically, in the presence of cerebellar atrophy, the eyes show horizontal gaze-evoked and vertical downbeat nystagmus. We investigated whether or not the cerebellar ocular motor syndrome also includes a torsional drift and, specifically, if it is independent from the drift in...

Purpose: To compare the efficacy and phacoemulsification parameters of torsional mode versus the combined torsional and longitudinal ultrasound mode in hard cataract of Egyptian patients. Methods: This randomized comparative study evaluated eyes 1, 7, and 30 days after phacoemulsification with an Infiniti Vision System using the torsional mode versus the combined torsional (100%) and longitudin...

AIM To compare the intraoperative performance and postoperative outcome after microcoaxial torsional phacoemulsification using either a Kelman or balanced phaco tip. METHODS Cataracts were treated using 2.2 mm microcoaxial torsional phacoemulsification using either a 45-degree mini-flared Kelman(®) or a 45-degree Intrepid(®) Balanced phaco tip. Intraoperative measurements included total ultra...

Single-molecule study of phenylenevinylene oligomers revealed distinct spectral forms due to different conjugation lengths which are determined by torsional defects. Large spectral jumps between different spectral forms were ascribed to torsional flips of a single phenylene ring. These spectral changes reflect the dynamic nature of electron delocalization in oligophenylenevinylenes and enable e...

Nonlinear torsional-flexural modal ;nteractions of a torsionally excited cantilever beam are studied in the case of one-to-one internal resonance. Discrete two DOF model is derived from the equations of motion for the continuous canthwer beam by using the Galerkin mode approx;mat;on method. The method of averaging is used to obtain the approx;mat;on to the response of the discrete model. Steady...