Mechanical

A motion analysis marker-based method of determining centre of pressure during two-legged hopping
The fixed position of force plates has led researchers to pursue alternative methods of determining centre of pressure (CoP) location. To date, errors reported using alternative methods to the force plate during dynamic tasks have been high. The aim of this study was to investigate the accuracy of a motion analysis marker-based system to determine CoP during a two-legged hopping task. Five mark...


Simulation of uphill/downhill running on a level treadmill using additional horizontal force
Tilting treadmills allow a convenient study of biomechanics during uphill/downhill running, but they are not commonly available and there is even fewer tilting force-measuring treadmill. The aim of the present study was to compare uphill/downhill running on a treadmill (inclination of±8%) with running on a level treadmill using additional backward or forward pulling forces to simulate the effe...
Finite element analyses of human vertebral bodies embedded in polymethylmethalcrylate or loaded via the hyperelastic intervertebral disc models provide equivalent predictions of experimental strength
Quantitative computer tomography (QCT)-based finite element (FE) models of vertebral body provide better prediction of vertebral strength than dual energy X-ray absorptiometry. However, most models were validated against compression of vertebral bodies with endplates embedded in polymethylmethalcrylate (PMMA). Yet, loading being as important as bone density, the absence of intervertebral disc (...


Increased Initial Cement-Bone Interlock Correlates With Reduced Tka Micro-Motion Following In Vivo Service
Aseptic loosening of cemented tibial components in total knee arthroplasty (TKA) has been related to inadequate cement penetration into the trabecular bone bed during implantation. Recent postmortem retrieval work has also shown there is loss of interlock between cement and bone by resorption of trabeculae at the interface. The goal of this study was to determine if TKAs with more initial inter...
Deformation of articular cartilage during static loading of a knee joint – experimental and finite element analysis
Novel conical beam CT-scanners offer high resolution imaging of knee structures with i.a. contrast media, even under weight bearing. With this new technology, we aimed to determine cartilage strains and meniscal movement in a human knee at 0, 1, 5, and 30 minutes of standing and compare them to the subject-specific 3D finite element (FE) model. The FE model of the volunteer's knee, based on the...


Key joint kinematic characteristics of the gait of fallers identified by principal component analysis
It has been reported that fallers have a higher risk of subsequent falls than non-fallers. Therefore, if the differences between the movements of recent fallers and non-fallers can be identified, such could be regarded as the basis of the high risk of falling of the former. The objective of the present study was the identification of the key joint kinematic characteristics of human gait related...
Human L3L4 intervertebral disc mean 3D shape, modes of variation, and their relationship to degeneration
Intervertebral disc mechanics are affected by both disc shape and disc degeneration, which in turn each affect the other; disc mechanics additionally have a role in the etiology of disc degeneration. Finite element analysis (FEA) is a favored tool to investigate these relationships, but limited data for intervertebral disc 3D shape has forced the use of simplified or single-subject geometries, ...

Hyperlipidemia affects multiscale structure and strength of murine femur
To improve bone strength prediction beyond limitations of assessment founded solely on the bone mineral component, we investigated the effect of hyperlipidemia, present in more than 40% of osteoporotic patients, on multiscale structure of murine bone. Our overarching purpose is to estimate bone strength accurately, to facilitate mitigating fracture morbidity and mortality in patients. Because i...
A study of the micro-machining process on quartz crystals using an abrasive slurry jet
An investigation of the micro-channelling process on a quartz crystal using an abrasive slurry jet is presented. An experimental study is conducted first to understand the material removal process, surface quality as well as the effect of process parameters on the channelling performance, namely the material removal rate, channel depth, top channel width and channel wall inclination angle. It i...

Effect of burnishing parameters on the surface quality and hardness
In industrial manufacturing applications to improve the surface quality of cylindrical parts such as valves, pistons of hydraulic or pneumatic cylinders, pump shafts and bearing bores, some surface-finishing processes such as grinding, super finishing and honing are applied. Nevertheless, none of them provides to improve fatigue, wear and corrosion resistance. Shot peening and case hardening ca...
Analysis of ignition risk in intermittent turning of UNS M11917 magnesium alloy at low cutting speeds based on the chip morphology
This study is based on a series of turning tests of UNS M11917 magnesium alloy, using low cutting speeds to emulate the conditions of repair and maintenance operations. More specifically, intermittent turning process, using both dry machining and minimum quantity lubrication system, is analysed. Cutting operations are done to evaluate the chip morphology obtained in order to assess their suitab...

Modeling and Control of a Wave Energy Farm Including Energy Storage for Power Quality Enhancement: the Bimep Case Study
This paper presents a complete wave-to-wire approach to the modeling of wave energy farms. It captures all the main peculiarities of such applications, from the variability of sea waves to the issues related to the grid integration of a multi-MW wave farm, including the hydrodynamic modeling of wave energy converters (WECs). The paper specifically discusses the different levels of control of a ...
Coordinating Wind Farms and Battery Management Systems for Inter-Area Oscillation Damping: A Frequency-Domain Approach
This paper presents a set of linear control designs for shaping the inter-area oscillation spectrum of a large radial power system through coordinated control of a wind farm and a battery energy system (BES). We consider a continuum representation of the power system with the wind and battery power modeled as point-source forcings. A spectral analysis of the system demonstrates that its oscilla...
Small-Disturbance Angle Stability Control With High Penetration of Renewable Generations
Growth and penetration of renewable energy has been remarkable during the last few years in many power systems around the world. Essentially, there are two major technologies responsible for the growth, namely wind and photovoltaic. The technologies involved in harnessing energy from wind and sun are distinctly different in dynamic characteristics and limitations. Consequently, their influence ...
Governor Rate-Constrained OPF for Primary Frequency Control Adequacy
The integration of non-dispatchable generation has led to a change in the dynamics of primary frequency response. This change, mostly driven by the limited contribution of non-dispatchable generation to both total system inertia and governor response, may deteriorate the performance of current practices for determining primary reserves to the extend that real time operation reliability may no l...