( ( ( microscopic details ) ( of ( friction 8 ) ) ) . )
(ROOT (NP (NP (JJ microscopic) (NNS details)) (PP (IN of) (NP (NN friction) (CD 8))) (. .)))
microscopic  details of friction 8.
(ROOT (S (NP (NN Friction) (NN force)) (VP (VBZ is) (VP (VBN caused) (PP (IN by) (NP (NP (JJ microscopic) (NNS bumps)) (, ,) (VP (VBZ lumps)) (, ,) (CC and) (NP (NP (NNS imperfections)) (VP (VBG colliding))))))) (. .)))