Friction analysis is proposed as the application of general control analysis to single enzymes to describe the control of elementary kinetic steps on the overall catalytic rate. For each transition, a friction coefficient is defined that measures the sensitivity of the turnover rate to the free energy of the transition state complex of the transition. The latter is captured in a single property...

Friction coefficients are measured in ultrahigh vacuum using a tungsten carbide tribopin against thin films of sodium chloride and potassium iodide deposited onto clean iron. It is found, in accordance with previous measurements for potassium chloride on iron, that the friction coefficient falls from an initial value of 2 for the clean iron surface to a minimum value after a few tens of Ångstro...

BACKGROUND AND OBJECTIVES Studies have demonstrated that some cutaneous biophysical properties vary with age, gender and body sites. However, the characteristics of the skin friction coefficient in different genders and age groups have not yet been well established. In the present study, we assess the skin friction coefficient in a larger Chinese population. METHODS A total of 633 subjects (3...

A friction coefficient is defined as the ratio of the friction force to the applied normal force. Despite the disarming simplicity of its calculation, there are practical challenges that make low values of friction coefficient difficult to accurately quantify. The connections of imperfect parts in friction measurement devices (called tribometers) produce small misalignments between the transduc...

The idea that snow avalanches might behave as granular flows, and thus be described as Coulomb fluid flows, came up very early in the scientific study of avalanches, but it is not until recently that field evidence has been provided that demonstrates the reliability of this idea. This paper aims to specify the bulk frictional behaviour of snow avalanches by seeking a universal friction law. Sin...

Friction plays an important role in the behavior of flowing granular media. The effective friction coefficient is a description of shear strength in both slow and rapid flows of these materials. In this paper, we study the steady state effective friction coefficient μ in a granular material in two steps. First, we develop a new relationship between the steady state effective friction coefficien...

The tire-road friction coefficient is critical to the performance of mobile robots working outdoors. However, it is difficult to measure using commercially available technology sensors. This paper presents a method of estimating the tire-road friction coefficient using a disturbance observer (DO) with compensator; the chassis speed is not needed. In this paper, the torque produced by the tire-r...

This paper presents frictional characteristics of thrust bearing in scroll compressor. The coefficient of friction in thrust bearing was measured by both elemental friction test and loss classification based on the performance test of actual scroll compressor, and investigated frictional characteristics focusing on the behavior of sliding portion which affects the generation of oil film by expe...

In vivo frictional properties of human skin and five materials, namely aluminium, nylon, silicone, cotton sock, Pelite, were investigated. Normal and untreated skin over six anatomic regions of ten normal subjects were measured under a controlled environment. The average coefficient of friction for all measurements is 0.46+/-0.15 (p<0.05). Among all measured sites, the palm of the hand has the ...