OBJECTIVE The aim of this article was to assess how intraoral biodegradation influenced the surface characteristics and friction levels of metallic brackets used during 12 and 24 months of orthodontic treatment and also to compare the static friction generated in these brackets with four different methods of the ligation of orthodontic wires. MATERIAL AND METHODS Seventy premolar brackets as ...

This paper deals with the full discretization of quasistatic 3D Signorini problems with local Coulomb friction and a coefficient of friction which may depend on the solution. After a time discretization we obtain a system of static contact problems with Coulomb friction. Each of these problems is solved by the T-FETI domain decomposition method used in auxiliary contact problems with Tresca fri...

We present results from an independent analysis of friction that more generally addresses all crystalline materials by an extension of coincident site lattice theory and dislocation drag. Calculations for graphitic friction are carried out and agree in magnitude with experimental friction forces. More interestingly, static, dynamic and anisotropic friction forces, incommensurability effects and...

Static friction in shearing mode can be expressed as the product of the shear strength of the interface and the real contact area. The influence of roughness on friction in elastic adhesive contact is analyzed. Special attention is paid to low loading conditions, in which the number of contact points is small. The models are used to analyze a friction experiment in a MEMS friction meter.

In general, externally powered prostheses do not provide proprioceptive feedback and thus require the user to rely on cognitively expensive visual feedback to effectively control the prosthesis. Applying the concept of extended physiological proprioception (EPP) to externally powered prostheses provides direct feedback to the user's proprioceptive system regarding the position, velocity, and fo...

We develop a theoretical description for mechanically stable frictional packings in terms of the difference between the total number of contacts required for isostatic packings of frictionless disks and the number of contacts in frictional packings, m=Nc0 - Nc. The saddle order m represents the number of unconstrained degrees of freedom that a static packing would possess if friction were remov...

In this paper we correlate the Atomic Force Microscope probe movement with surface location while scanning in the imaging and Force versus distance modes. Static and dynamic stick-slip processes are described on a scale of nanometres to microns on a range of samples. We demonstrate the limits and range of the tip apex being fixed laterally in the force versus distance mode and static friction s...

This paper presents a comparative study among friction behavior of several double-acting pneumatic actuators available to industrial use. A brief review covering the manner that pneumatic actuator manufacturers and current literature approach friction force and its usual models also is presented. After depicting friction test methodology and test apparatus, the comparison work is carried out th...

Multimodal simulations augment the presentation of abstract concepts facilitating theoretical models understanding and learning. Most simulations only engage two of our five senses: sight and hearing. If we employ additional sensory communication channels in simulations, we may gain a deeper understanding of illustrated concepts by increasing the communication bandwidth and providing alternativ...