Relative humidity and wetting affect friction between apple and flat surfaces.

摘要

The objective of this study was to determine the influence of relative humidity and dipping in water on the static and dynamic coefficients of friction of apple on four surface types. Knowledge of the coefficient of friction of fruits and vegetablesis useful in the design of handling equipment and improving the production systems that will reduce apple damage. Two different cultivars (Gala and McLemore) were tested using a linear sliding friction test device connected to an Instron universal testing machine, data acquisition system, and a personal computer. The tests were carried out with ten replications per treatment combination under constant sliding speed and sample temperature. Samples were placed in air at 35, 55, 70, 95% RH and dipped in water. Relative humidity (RH) and dipping in water (WD) treatments had significant effect on both static and dynamic coefficients of friction. Changes in static coefficient of friction (SCF) with increasing RH were different for Gala and McLemore apples.Coefficient of friction tended to increase or decrease depending on sample moisture content, type of sliding surface and cultivar.