( ( ( These ( potential propellants ) ) ( were ( culled ( from ( ( the analysis ) ( of ( solid ( hydrogen ( and ( metallic clusters ) ) ) ) ) ) ) ) ) ) ( , ( ( metal atom ) ( ( ( ( ( doped ( cryogenic solids ) ) , ) and ) ( solids ( with ( impurities ( previously conducted ) ) ) ) ) . ) ) ) )
(ROOT (S (S (NP (DT These) (JJ potential) (NNS propellants)) (VP (VBD were) (VP (VBN culled) (PP (IN from) (NP (NP (DT the) (NN analysis)) (PP (IN of) (NP (JJ solid) (NN hydrogen) (CC and) (NN metallic) (NNS clusters)))))))) (, ,) (NP (NN metal) (NN atom)) (VP (VP (VBD doped) (NP (JJ cryogenic) (NNS solids))) (, ,) (CC and) (VP (VBZ solids) (PP (IN with) (NP (NP (NNS impurities)) (VP (ADVP (RB previously)) (VBN conducted)))))) (. .)))
These potential propellants were culled from the analysis of solid hydrogen and metallic clusters, metal atom doped cryogenic solids, and solids with impurities previously conducted.
(ROOT (S (NP (JJ Metallic) (NNS solids)) (VP (VBP are) (VP (VBN composed) (ADVP (RB entirely)) (PP (IN of) (NP (JJ metallic) (NNS atoms))))) (. .)))