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