Nowadays, piezoelectric materials have wide applications in various industries. Therefore, investigation of these materials and their applications has a special importance. In this paper first, the natural frequencies of a traveling-wave piezoelectric motor are achieved, using finite elements simulations. Then, applying an alternative electrical voltage to the piezoelectric ring, a traveling wa...

BACKGROUND Screw-rod constructs have been widely used to correct spinal deformities, but the effects of different screw-rod systems on anti-rotational torque have not been determined. This study aimed to analyze the biomechanical effect of different rod-screw constructs on anti-rotational torque. METHODS Three conventional spinal screw-rod systems (Legacy, RF-F-10 and USSII) were used to test...

Horizontal directional drilling (HDD) is widely used in soil and rock engineering. In a variety of conditions, it is necessary to estimate the torque required for performing the reaming operation. Nevertheless, there is not presently a convenient method to accomplish this task. In this paper, to overcome this difficulty based on the basic concepts of rock engineering systems (RES), a model for ...

Currently, there are several possibilities of abutments connections in dental implants. The most common design in use is the external hexagon connection, which, besides the function of transmitting torque at surgical placement, also works as an antirotational mechanism and orientation of the abutment for single tooth prostheses. Several researchers have suggested that screw joint stability is d...

BACKGROUND Football turf is increasingly used in European soccer competition. Little is known on the rotational torque that players experience on these fields. High rotational torques between the shoe outsole and the sports surface has been correlated with torsional injuries of the lower limb and knee. PURPOSE To evaluate the effect of six parameters that could influence the rotational torque...

When executing turning maneuvers, manual wheelchair users must overcome the rotational inertia of the wheelchair system. Differences in wheelchair rotational inertia can result in increases in torque required to maneuver, resulting in greater propulsion effort and stress on the shoulder joints. The inertias of various configurations of an ultralightweight wheelchair were measured using a rotati...

We describe an apparatus that can measure the instantaneous angular displacement and torque applied to a quartz particle which is angularly trapped. Torque is measured by detecting the change in angular momentum of the transmitted trap beam. The rotational Brownian motion of the trapped particle and its power spectral density are used to determine the angular trap stiffness. The apparatus featu...

PURPOSE This in vitro study aimed to evaluate the effect of implant connection design (external vs. internal) on the fit discrepancy and torque loss of zirconia and titanium abutments. MATERIALS AND METHODS Two regular platform dental implants, one with external connection (Brånemark, Nobel Biocare AB) and the other with internal connection (Noble Replace, Nobel Biocare AB), were selected. Se...

This paper proposes a new non‐magnetic motor with a rotor rotated by using the resonance en‐ ergy of a bimorph cantilever beam excited by electrostatic force. The use of flexible material en‐ ables conversion of translational vibration to rotary movement in one direction. Basic character‐ istics of a prototype motor with two bimorph cantilever beams, such as rotational speed, output torque, and...