Main objective of the current study

Main objective of the current study is to investigate the contribution
of micro-hysteresis to rubber friction in case of apparently
smooth surfaces. In order to attain this objective it is needed
to reanalyze measurement results of [6], and compare them
additional test results. Like in [6], friction test results reported for
nitrile butadiene rubber (NBR) are in the focus of this work
because, contrary to its great practical importance, surprisingly
little attention is paid in the literature to oil lubricated sliding
friction of NBR squeezing against (apparently) smooth steel