Synovial fluid plays an important role in lubricating synovial joints. Its main constituents are hyaluronic acid (HA) and γ-globulin, acting as boundary lubricants for articular cartilage. The aim of the study was to demonstrate the concentration-dependent effect of HA and γ-globulin on the boundary-lubricating ability of human osteoarthritis (OA) cartilage. Normal, early and advance stage arti...

The scan-velocity dependence of friction force microscopy (FFM) is characterized on gelatin films and related to the rate dependence of molecular relaxations. For selected scanning-parameter values the velocity dependence of frictional force is affected by the measurement process, because of energy imparted to the tip-sample contact region: a peak in the friction-velocity relationship, attribut...

The microstructure investigated in this study was inspired by the anisotropic microornamentation of scales from the ventral body side of the California King Snake (Lampropeltis getula californiae). Frictional properties of snake-inspired microstructured polymer surface (SIMPS) made of epoxy resin were characterised in contact with a smooth glass ball by a microtribometer in two perpendicular di...

Frictional vibration and noise caused by water-lubricated rubber stern tube bearings, which are generated under extreme conditions, severely threaten underwater vehicles' survivability and concealment performance. This study investigates the effect of flaky and spherical MoS2 nanoparticles on tribological properties and damping capacity of water-lubricated rubber materials, with the aim of decr...

The loss mechanisms responsible for the observed attenuation in soils are often unclear and controversial. This is particularly the case with the small-strain damping Dmin in air-dry sands. Ultimately, physical explanations must accommodate the observed effects of confinement, strain level, frequency, and load repetition. Three hypotheses are explored herein: measurement bias, thermoelastic rel...

The frictional forces between the sports footwear and the ground can induce distorsion trauma to the lower extremity. Two cases are reported in which fractures about the ankle are related to this friction. An adjustment and reduction of the frictional forces are recommendable.

Theoretical study of non-Newtonian effects of second-order fluids on the performance characteristics of inclined slider bearings is presented. An approximate method is used for the solution of the highly nonlinear momentum equations for the second-order fluids. The closed form expressions for the fluid film pressure, load carrying capacity, frictional force, coefficient of friction, and centre ...

Much of the recent studies have been motivated by the idea that a frictional transition drives these phenomena, and a theoretical framework has been proposed [1]. The rheological behavior predicted by the theory has been verified in numerical simulations [2] and experiments [3]. The experimental study reported in the recent PNAS paper by Cécile Cavaud and collaborators, “reveals” the underlying...

Frictional convergence in an atmospheric boundary layer topped by a stable free troposphere is considered. In agreement with extensive previous work, we find that atmospheric stability reduces the vertical scale of the free tropospheric secondary circulation associated with frictional convergence. Associated with this reduction in vertical scale is a proportional reduction in the time scale for...

physical properties of four common iranian varieties of canola seeds (hyola, okapi, orient and slm) were evaluated as a function of their moisture contents. the average seed length and thousand seed mass varied linearly from 1.925 to 2.262 mm and from 3.06 to 4.84 g, respectively. the average diameter, geometric mean diameter, and sphericity varied non-linearly from 1.475 to 1.911 mm, 1.625 to ...