Unlabelled: The required coefficient of friction (RCOF) is an important predictor for slip incidents. Despite the wide use of the RCOF there is no standardised method for identifying the RCOF from ground reaction forces. This article presents a comparison of the outcomes from seven different methods, derived from those reported in the literature, for identifying the RCOF from the same data. While commonly used methods are based on a normal force threshold, percentage of stance phase or time from heel contact, a newly introduced hybrid method is based on a combination of normal force, time and direction of increase in coefficient of friction. Although no major differences were found with these methods in more than half the strikes, significant differences were found in a significant portion of strikes. Potential problems with some of these methods were identified and discussed and they appear to be overcome by the hybrid method.
Practitioner Summary: No standard method exists for determining the required coefficient of friction (RCOF), an important predictor for slipping. In this study, RCOF values from a single data set, using various methods from the literature, differed considerably for a significant portion of strikes. A hybrid method may yield improved results.
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http://dx.doi.org/10.1080/00140139.2011.642008 | DOI Listing |
Nanoscale
January 2025
Pro2TecS - Chemical Product and Process Technology Research Center. Department of Chemical Engineering and Materials Science. Universidad de Huelva. ETSI, Campus de "El Carmen", 21071 Huelva, Spain.
This study explores the preparation of lubricating oleo-dispersions using electrospun nanofibrous mats made from low-sulfonate lignin (LSL) and polycaprolactone (PCL). The rheological and tribological properties of the oleo-dispersions were significantly modulated for the first time through the exploration of LSL/PCL ratio and electrospinning conditions such as applied voltage, distance between the tip and collector, flow rate, ambient humidity, and collector configuration. Adequate uniform ultrathin fibers and Small-amplitude oscillatory shear (SAOS) functions of the oleo-dispersions, with storage modulus values ranging from 10 to 10 Pa at 25 °C, were obtained with a flow rate of 0.
View Article and Find Full Text PDFBiophys Rev
December 2024
Department of Physics, Lancaster University, Lancaster, LA1 4YB UK.
Friction is a critical factor in the proper functioning of human organs as well as in the potential development of disease. It is also important for the design of diagnostic and interventional medical devices. Nanoscale surface roughness, viscoelastic or plastic deformations, wear, and lubrication all influence the functions of individual cells.
View Article and Find Full Text PDFMar Pollut Bull
January 2025
Department of Materials Science and Engineering, Dalian Maritime University, Dalian 116026, PR China; Dalian Key Laboratory of Internal Combustion Engine Tribology and Reliability Engineering, Dalian 116026, PR China. Electronic address:
As a global challenge, marine biofouling is causing serious economic losses and adverse ecological impacts. In recent years, a variety of promising and environmentally friendly anti-fouling strategies have emerged, among which the excellent anti-fouling performance of bionic autocrine coatings has been recognized. However, bionic autocrine coatings still suffer from uncontrollable secretion behavior, poor mechanical stability, and poor abrasion resistance.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, 153-8904, Tokyo, Japan; Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, 153-8505, Tokyo, Japan. Electronic address:
Phase separation, a fundamental phenomenon in both natural and industrial settings, involves the coarsening of domains over time t to reduce interfacial energy. While well-understood for simple viscous liquid mixtures, the physical laws governing coarsening dynamics in complex fluids, such as colloidal suspensions, remain unclear. Here, we investigate colloidal phase separation through particle-based simulations with and without hydrodynamic interactions (HIs).
View Article and Find Full Text PDFSoft Matter
January 2025
Politecnico di Milano, 20133 Milano, Italy.
Identical, inelastic spheres crystallize when sheared between two parallel, bumpy planes under a constant load larger than a minimum value. We investigate the effect of the inter-particle friction coefficient of the sheared particles on the flow dynamics and the crystallization process with discrete element simulations. If the imposed load is about the minimum value to observe crystallization in frictionless spheres, adding small friction to the granular assembly results in a shear band adjacent to one of the planes and one crystallized region, where a plug flow is observed.
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