BACKGROUND Increasing the coefficient of friction of the shoe-surface interaction has been shown to lead to increased incidence of anterior cruciate ligament (ACL) injuries, but the causes for this increase are unknown. Previous studies indicate that specific biomechanical measures during landing are associated with an increased risk for ACL injury. HYPOTHESIS At foot contact during a sideste...

in the present paper, an analysis was carried out to investigate effects of radiation on a free convection flow bounded by a vertical surface embedded in a porous medium with constant suction velocity. it was under the influence of uniform magnetic field in the presence of a homogenous chemical reaction and viscous dissipation with constant heat and mass flux. the non-dimensional governing equa...

We introduce a method of observer design for systems described by a linear part with a nonlinear perturbation, where the perturbation is parameterized by a vector of unknown, constant parameters. The design is modular, and consists of a modified high-gain observer that estimates the states of the system together with the full perturbation, and a parameter estimator. The parameter estimator is c...

Due to the need for practical cooling technologies which could dissipate high heat fluxes, an experimental study of pressure drop in micro-channel was performed. In this work, laminar flow friction factors were determined using gas (air) as flow medium. Pressure drop vs flow rate data were used to evaluate friction factors in two parallel microchannels, namely MCP1 and MCP2 (1.0 mm deep x 0.240...

The thermo-hydraulic behavior of the air flow over a two dimensional ribbed channel wasnumerically investigated in various rib-width ratio configurations (B/H=0.5-1.75) atdifferent Reynolds numbers, ranging from 6000 to 18000. The capability of differentturbulence models, including standard k-ε, RNG k-ε, standard k-ω, and SST k-ω, inpredicting the heat transfer rate was compared with the experi...

The hydrostatic extrusion is a new method of extrusion process. The most important advantage of this method is reduction of friction and close tolerance for the coating thickness. In this study, the hydrostatic extrusion simulation of bimetallic wires has performed using of finite element method. In the following the advantages of hydrostatic extrusion compared to the direct extrusion are prese...

A semi-empirical model is presented that describes the development of a fully developed turbulent boundary layer in the presence of surface roughness with length scale ks that varies with streamwise distance x. Interest is centred on flows for which all terms of the von Kármán integral relation, including the ratio of outer velocity to friction velocity U+ ∞ ≡ U∞/uτ , are streamwise constant. F...

During the last decades, under the increasing demand for more accurate high-performance motion systems, various friction models appropriate for control purpose of mechanical systems have been proposed. Most of these friction models formulate a heuristic dynamical model based on a few observed typical friction properties (e.g. a Stribeck curve for constant velocities and a hysteresis behaviour i...

In many sliding systems consisting of solid object on a solid substrate under dry condition, the friction force does not depend on the apparent contact area and is proportional to the loading force. This behaviour is called Amontons' law and indicates that the friction coefficient, or the ratio of the friction force to the loading force, is constant. Here, however, using numerical and analytica...