BACKGROUND Conventional (rigid) fusion instrumentation is believed to accelerate the degeneration of adjacent discs by increasing stresses caused by motion discontinuity. Fusion instrumentation that employs reduced rod stiffness and increased axial motion, or dynamic instrumentation, may partially alleviate this problem, but the effects of this instrumentation on the stresses in the adjacent di...

The article presents the transients analysis of the substation grounding systems and transmission line tower footing resistances which can affect to the back-flashover (BF) or overvoltage across insulator chain in an HV power systems by using EMTP-RV software. The related transient modeling of the grounding systems is based on a transmission line (TL) model with considering the soil ionization....

This article introduces an innovative system for enhancing the seismic performance of a structure through facilitating large rotational (rocking) motion to occur without risking overturning. The innovation this study is in use tendons consisting Nickel-Titanium (superelastic) alloy connected series with steel impose partial restraints when experiencing rocking motion. Importantly, fully recover...

A torque measurement system was added to a widely used hip wear simulator, the biaxial rocking motion device. With the rotary transducer, the frictional torque about the drive axis of the biaxial rocking motion mechanism was measured. The principle of measuring the torque about the vertical axis above the prosthetic joint, used earlier in commercial biaxial rocking motion simulators, was shown ...

Many space applications require robotic manipulators which have large workspace and are capable of precise motion. Micro-macro manipulators are considered as the best solution to this demand. Such systems consist of a long flexible arm and a short rigid arm. Kinematic redundancy and presence of unactuated flexible degrees of freedom, makes it difficult to control micro-macro manipulators. This ...

OBJECTIVE Rod-screw fixation systems are widely used for spinal instrumentation. Although many biomechanical studies on rod-screw systems have been carried out, but the effects of rod contouring on the construct strength is still not very well defined in the literature. This work examines the mechanical impact of straight, 20° kyphotic, and 20° lordotic rod contouring on rod-screw fixation syst...

In a damage avoidance design perspective, seismic rocking of rigid-like blocks, such as masonry walls, precast r.c./timber panels, art objects, etc., can be controlled through viscous elastic dampers. This paper discusses how to perform risk assessment walls undamped and damped by viscous-elastic dampers installed at the top them. Firstly, preliminary fragility analysis allows understanding rol...

Magnetic Resonance Imaging (MRI) is increasingly being used for improving tumor delineation and tumor tracking in the presence of respiratory motion. The purpose of this work is to design and build an MR compatible motion platform and to use it for evaluating the geometric accuracy of MR imaging techniques during respiratory motion. The motion platform presented in this work is composed of a mo...

Abstract To study the analysis and optimization of motion reliability multifunctional nursing bed mechanism, ADAMS software platform was chosen to simulate parametric modeling with consideration dimensional clearance errors. Taking back-raising mechanism as an example, we verify accuracy model by comparing experimental data. Based on effect error, a response surface motor end hinge clearance, p...