We biomechanically investigated whether the standard dynamic hip screw (DHS) or the DHS blade achieves better fixation in bone with regard to resistance to pushout, pullout and torsional stability. The experiments were undertaken in an artificial bone substrate in the form of polyurethane foam blocks with predefined mechanical properties. Pushout tests were also repeated in cadaveric femoral he...

A~tract. The finite amplitude, coupled shear-torsional motion of a circular disk supported between identical rubber spring cylinders is studied. The material of the springs is assumed to be an incompressible elastic material. The oscillatory motion of the disk is studied for two different cases. In the first case, the material of the spring is assumed to be an incompressible elastic material wh...

Torsional problems of the femur have been traditionally treated by a proximal osteotomy with internal fixation. We elected to perform femoral derotational osteotomies distally. Between September 1994 and April 2001, supracondylar osteotomies were performed on 38 femora in 21 children with torsional and angular deformities. The average age was 9 years (range 5-15 years). Twenty-three femora had ...

Horizontal, vertical, and torsional eye movements were recorded using the magnetic search-coil technique during linear accelerations along the interaural (IA) and dorsoventral (DV) head axes. Four squirrel monkeys were translated sinusoidally over a range of frequencies (0.5-4.0 Hz) and amplitudes (0.1-0.7 g peak acceleration). The linear vestibuloocular reflex (LVOR) was recorded in darkness a...

A hybrid longitudinal-torsional ultrasonic transducer is designed and fabricated in this research. The design of the transducer was performed using the FE method with ABAQUS software, with the aim of combining the longitudinal and torsional vibration modes. The transducer horn is then fabricated using a 4-axis milling machine. The PZT stacks are employed in order to excite the transducer. The t...

The characteristics of phonons, i.e. linearized normal modes of vibration, provide important insights into many aspects of crystals, e.g. stability and thermodynamics. In this paper, we use the Objective Structures framework to make concrete analogies between crystalline phonons and normal modes of vibration in non-crystalline but second derivatives is block-circulant. The block-circulant natur...

The non-resonant dynamic galloping of an iced, electrical transmission line is studied. Conditions and trends for the initiation of galloping have been given previously. Boundaries are presented here at which a periodic plunge or torsional motion loses stability and bifurcates into a quasi-periodic (mixed-mode) motion. Specific attention is given to the overall effects of an iced line’s eccentr...

This paper is concerned with the derivative feedback control of a 2-degree-of-freedom (2-DOF) torsional bar with parameter perturbations. The time-delay is introduced into the controller and the maximum allowed time-delay bound is estimated by employing a discretized Lyapunov functional method. It is shown, through a numerical example with simulation results, that suitably introducing time-dela...