In this paper, the effects of transverse cracks on rotating shaft are studied. According to earlier works, crack shaft failure decrease the critical speed of the shaft and also exhibit a nonlinear vibration behaviour leading to increases the amplitude of 1X and 2X harmonics (first and second order of rotational speed in torsional vibration). This suggests that the application of order analysis ...

Cone penetration test is one of the most common in-situ tests for pile analysis given that by its analogy as a model pile, the measured cone resistance and sleeve friction can be employed for estimation of pile unit toe and shaft resistances, respectively. In this paper, group method of data handling (GMDH)-type neural networks optimized using Genetic algorithms (GAs) are used for modelling the...

Follow-the-leader propagation allows for the insertion of flexible surgical instruments along curved paths, reducing the access required for natural orifice transluminal endoscopic surgery. Currently, the most promising follow-the-leader instruments use the alternating memory method containing two mechanical memory-banks for controlling the motion of the flexible shaft, which reduces the number...

UNLABELLED Early failures after hip resurfacing often are the result of technical errors in placing the femoral component. We asked whether image-free computer navigation decreased the number of outliers compared with the conventional nonnavigated technique. We retrospectively compared 51 consecutive hip resurfacings performed using image-free computer navigation with 88 consecutive hip resurfa...

BACKGROUND Fractures of the femoral shaft are mostly the result of high-energy accidents that also cause multiple trauma injuries, in particular ipsilateral knee and hip injuries. The purpose of this study was to investigate the incidence of injuries associated with femoral shaft fractures and how many of them were undetected. METHODS We studied 148 patients (150 femoral shaft fractures) with...

This paper focuses on the modelling, simulation and analysis of the behaviour of the electromagnetic shaft synchronization system with two identical single-phase induction motors. Motors speed-control and their synchronization are achieved by this electromagnetic shaft. A mathematical model has been suggested to describe this synchronization system. The traditional electromagnetic shaft synchro...

Many systems can be approximated as linear with coefficients that vary periodically with time. For example, an anisotropic shaft rotating at constant speed on anisotropic bearings can be modeled as periodically time varying (PTV). Similar models can be obtained for wind turbines, some mechanisms, etc... However, the vast majority of modal analysis algorithms and techniques apply only to linear ...

BACKGROUND There is evidence that glycosaminoglycans (GAGs) are present in the hair shaft within the follicle but there are no studies regarding GAGs isolation and measurement in the human hair shaft over the scalp surface, it means, in the free hair shaft. OBJECTIVE The purpose of our research was to isolate and measure the total GAGs from human free hair shaft. METHODS Seventy-five health...

We have investigated the accuracy of placement of the femoral component using imageless navigation in 100 consecutive Birmingham Hip Resurfacings. Pre-operative templating determined the native neck-shaft angle and planned stem-shaft angle of the implant. The latter were verified post-operatively using digital anteroposterior unilateral radiographs of the hip. The mean neck-shaft angle determin...

BACKGROUND There are many methods for treating femoral shaft aseptic nonunions of which exchange nailing is the simplest technique. However, the reported success rate varies. Therefore, a prospective study was conducted to further clarify the role of exchange nailing. METHODS From October 1994 through December 1999, 40 femoral shaft aseptic nonunions in 39 patients were treated using exchange...