Atomically flat and clean metal surfaces exhibit a regime of ultra-low friction at low normal loads. Atomic force microscopy, performed in ultra-high vacuum on Cu(100) and Au(111) surfaces, reveals a clear stick-slip modulation in the lateral force but almost zero dissipation. Significant friction is observed only for higher loads (*4– 6 nN above the pull-off force) together with the onset of w...

The development of Scanning Force Microscopy has provided us with tools to study friction and wear on the nanometer scale. The atomic granularity of matter shows up in the lateral force which is necessary to slide a small contact over a flat surface. Also, mechanical damage of a sample surface can be monitored with monolayer resolution [1]. The laws which determine the dependence of friction on...

An approach to estimate the tire{road friction during normal drive using only the wheel slip, that is, the relative diierence in wheel velocities, is presented. The driver can be informed about the maximal friction force and be alarmed for sudden changes. Friction related parameters are estimated using only signals from standard sensors in a modern car, and the physical relation between these p...

Virtual reality technologies are increasingly being applied to various fields. Recently, from the importance of the sense of touch for human-computer interaction, the force feedback devices have been developed and put into practical use. For high fidelity simulation of phenomena in real-world, the haptic information such as weight, friction, and elasticity etc., are important. In this paper we ...

The effect of C60 molecular rotation on the nanotribological properties of C60 single crystal surfaces has been studied by atomic/frictional force microscopy. The orientational order-disorder phase transition, in which the high temperature C60 free rotation is reduced to a low temperature hindered rotation, is shown to give rise to an abrupt change in friction and adhesion. This change in frict...

Silicon dioxide films are extensively used in nano and micro-electromechanical systems. Here we studied the influence of an external electric field on the mechanical properties of a SiO2 film by using nanoindentation technique of atomic force microscopy (AFM) and friction force microscopy (FFM). A giant augmentation of the relative elastic modulus was observed by increasing the localized electr...

UNLABELLED The relationship between orthodontic force and friction produced from an archwire and brackets affects the sliding of the wire in the leveling stage. OBJECTIVE The purpose of this study was to evaluate the relationship between force and friction in a small esthetic nickel-titanium (Ni-Ti) wire. MATERIAL AND METHODS Five esthetic wires (three coated and two plated) and two small, ...

We present a model describing friction due to the thermally activated formation and rupture of molecular bonds between two surfaces, with long molecules on one surface attaching to discrete or continuous binding sites on the other. The physical assumptions underlying this model are formalized using a continuum approximation resulting in a class of master-equation-like partial differential equat...

A review of the problem of aircraft skidding on Naval airfields during landings and a thorough literature search on the work conducted on friction coefficient were made. The literature search revealed that much ,vork has been conducted on basic theoretical studies of friction coefficient, on development of friction measuring devices, and on investigations to determine the factors which affect t...

We calculate the van der Waals friction between two semi-infinite solids in normal relative motion and find a drastic difference in comparison with the parallel relative motion. The case of the good conductors is investigated in details both within the local optic approximation , and using a non-local optic dielectric approach. We show that the friction may increase by many order of magnitude w...