( ( the ( composite material ) ) ( ( is ( ( ( used ( most often ) ) ( as ( an element ) ) ) ( for ( ( detecting ( temperature changes ) ) ( by ( means ( of ( ( differential ( thermal expansion ) ) ( in ( the ( two layers ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT the) (JJ composite) (NN material)) (VP (VBZ is) (VP (VBN used) (ADVP (RBS most) (RB often)) (PP (IN as) (NP (DT an) (NN element))) (PP (IN for) (S (VP (VBG detecting) (NP (NN temperature) (NNS changes)) (PP (IN by) (NP (NP (NNS means)) (PP (IN of) (NP (NP (NN differential) (JJ thermal) (NN expansion)) (PP (IN in) (NP (DT the) (CD two) (NNS layers)))))))))))) (. .)))
the composite material is used most often as an element for detecting temperature changes by means of differential thermal expansion in the two layers.
(ROOT (S (NP (DT The) (NN term) (JJ thermal) (NN expansion)) (VP (VBZ is) (VP (VBN used) (S (VP (TO to) (VP (VB describe) (NP (NP (DT the) (NN change)) (PP (IN in) (NP (NN size) (CC or) (NN volume))) (PP (IN of) (NP (NP (DT a) (VBN given) (NN mass)) (PP (IN with) (NP (NN temperature))))))))))) (. .)))