scholarly journals Analysis of contact area between water and irregular fibrous surface for prediction of wettability

RSC Advances ◽  
2016 ◽  
Vol 6 (77) ◽  
pp. 73313-73322 ◽  
Author(s):  
Yue Yuan ◽  
Seong-O Choi ◽  
Jooyoun Kim
Keyword(s):  
Contact Area ◽  
Area Fraction ◽  
Roughened Surface ◽  
Baxter Model ◽  
Solid Area

A characterization method was developed, which visualizes the wetted solid area fraction (fs) of the Cassie–Baxter model on a roughened surface.

scholarly journals Surface characteristics influencing bacterial adhesion to polymeric substrates

RSC Advances ◽  
2017 ◽  
Vol 7 (23) ◽  
pp. 14254-14261 ◽  
Author(s):  
Yue Yuan ◽  
Michael P. Hays ◽  
Philip R. Hardwidge ◽  
Jooyoun Kim
Keyword(s):  
Surface Area ◽  
Solid Surface ◽  
Bacterial Adhesion ◽  
Surface Characteristics ◽  
Area Fraction ◽  
Effective Surface Area ◽  
Effective Surface ◽  
Polymeric Substrates ◽  
Solid Area

Effective surface area on rough substrates for bacterial adhesion is examined by analyzing the solid area fraction of surfaces, where the bacterial medium is in contact with the solid surface.

Development of shear bands in annular shear granular flows

2002 ◽  
Vol 759 ◽  
Author(s):  
Payman Jalali ◽  
Mo Li
Keyword(s):  
Shear Rate ◽  
Shear Band ◽  
Granular Media ◽  
Shear Bands ◽  
Granular Flows ◽  
Area Fraction ◽  
Entire System ◽  
Local Properties ◽  
System Characteristics ◽  
Solid Area

ABSTRACTUsing hard-disk simulations of relatively dense packs of mono-sized system in an annular Couette geometry the formation of dilute regions inside the granular media, namely shear bands, are investigated. The results represent the influence of entire system characteristics such as solid area fraction and shear rate on the development of shear bands as well as the local properties of grains that cause them to participate in the formation of a shear band. Moreover, simulations have been performed for binary-sized system, which revealed that the formation of such diluted shear bands is unlikely.

The Distribution of Microcontact Area, Load, Pressure, and Flash Temperature Under the Greenwood-Williamson Model

1988 ◽  
Vol 110 (1) ◽  
pp. 106-111 ◽  
Author(s):  
J. I. McCool
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Contact Area ◽  
Random Variables ◽  
Area Fraction ◽  
Real Contact Area ◽  
Flash Temperature ◽  
Load Pressure ◽  
Average Behavior ◽  
Real Contact

Microcontact models provide average values of the random interfacial load, area and pressure between rough contacting surfaces. They do not provide a measure of the variability about that average. Events of tribological importance, however, are likely to be dependent on extreme rather than average behavior conditions. In this paper Monte Carlo simulation is used to determine the 75th and 90th percentiles of three dimensionless random variables as a function of the dimensionless separation of two contacting rough surfaces. These values may be used to determine the corresponding percentiles under the Greenwood-Williamson microcontact model of the distributions of 1) real contact area fraction, 2) the radius of the microcontact area, 3) microcontact load, 4) the maximum microcontact pressure and 5) the asperity flash temperature under low speed sliding conditions. A numerical example illustrates the computations.

Load-Bearing in the Ovine Medial Tibial Condyle: Effect of Meniscectomy

1993 ◽  
Vol 06 (02) ◽  
pp. 100-104 ◽  
Author(s):  
D. M. Pickles ◽  
C. R. Bellenger
Keyword(s):  
Knee Joint ◽  
Contact Area ◽  
Mammalian Species ◽  
Total Removal ◽  
Load Bearing ◽  
Human Knee ◽  
Biochemical Effects ◽  
Pressure Sensitive ◽  
Medial Meniscectomy ◽  
Tibial Condyle

SummaryTotal removal of a knee joint meniscus is followed by osteoarthritis in many mammalian species. Altered load-bearing has been observed in the human knee following meniscectomy but less is known about biochemical effects of meniscectomy in other species. Using pressure sensitive paper in sheep knee (stifle) joints it was found that, for comparable loads, the load-bearing area on the medial tibial condyle was significantly reduced following medial meniscectomy. Also, for loads of between 50 N and 500 N applied to the whole joint, the slope of the regression of contact area against load was much smaller. Following medial meniscectomy, the ability to increase contact area as load increased was markedly reduced.The load bearing area on the medial tibial condyle was reduced following meniscectomy.

An Analytical Thermodynamic Approach to Friction of Rubber on Ice

2012 ◽  
Vol 40 (2) ◽  
pp. 124-150
Author(s):  
Klaus Wiese ◽  
Thiemo M. Kessel ◽  
Reinhard Mundl ◽  
Burkhard Wies
Keyword(s):  
Coefficient Of Friction ◽  
Liquid Layer ◽  
Contact Area ◽  
Leading Edge ◽  
Viscous Friction ◽  
Analytical Approximation ◽  
Real Contact Area ◽  
Length Scales ◽  
Real Contact ◽  
Ice Surface

ABSTRACT The presented investigation is motivated by the need for performance improvement in winter tires, based on the idea of innovative “functional” surfaces. Current tread design features focus on macroscopic length scales. The potential of microscopic surface effects for friction on wintery roads has not been considered extensively yet. We limit our considerations to length scales for which rubber is rough, in contrast to a perfectly smooth ice surface. Therefore we assume that the only source of frictional forces is the viscosity of a sheared intermediate thin liquid layer of melted ice. Rubber hysteresis and adhesion effects are considered to be negligible. The height of the liquid layer is driven by an equilibrium between the heat built up by viscous friction, energy consumption for phase transition between ice and water, and heat flow into the cold underlying ice. In addition, the microscopic “squeeze-out” phenomena of melted water resulting from rubber asperities are also taken into consideration. The size and microscopic real contact area of these asperities are derived from roughness parameters of the free rubber surface using Greenwood-Williamson contact theory and compared with the measured real contact area. The derived one-dimensional differential equation for the height of an averaged liquid layer is solved for stationary sliding by a piecewise analytical approximation. The frictional shear forces are deduced and integrated over the whole macroscopic contact area to result in a global coefficient of friction. The boundary condition at the leading edge of the contact area is prescribed by the height of a “quasi-liquid layer,” which already exists on the “free” ice surface. It turns out that this approach meets the measured coefficient of friction in the laboratory. More precisely, the calculated dependencies of the friction coefficient on ice temperature, sliding speed, and contact pressure are confirmed by measurements of a simple rubber block sample on artificial ice in the laboratory.

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