title: Physical characterization and recovery of corroded fingerprint impressions from postblast copper pipe bomb fragments.
abstract: Pipe bombs made from 1 mm thick copper pipe were detonated with a low explosive power powder. Analysis of the physical characteristics of fragments revealed that the copper had undergone work hardening with an increased Vickers Hardness of 107HV1 compared with 80HV1 for unexploded copper pipe. Mean plastic strain prior to fracture was calculated at 0.28 showing evidence of both plastic deformation and wall thinning. An examination of the external surface showed microfractures running parallel with the length of the pipe at approximately 100 μm intervals and 1-2 μm in width. Many larger fragments had folded "inside out" making the original outside surface inaccessible and difficult to fold back through work hardening. A visual examination for fingerprint corrosion revealed ridge details on several fragments that were enhanced by selective digital mapping of colors reflected from the surface of the copper. One of these fingerprints was identified partially to the original donor.
authors.affiliation: Department of Chemistry, University of Leicester, George Porter Building, University Road Leicester, LE1 7RH, UK. jwb13@le.ac.uk
authors.forename: John W
authors.initials: JW
authors.lastname: Bond
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Brady
mesh_terms: D054042:Bombs; D003300:Copper; D003343:Corrosion; D003878:Dermatoglyphics; D005107:Explosions; D006801:Humans; D010781:Photography; D012984:Software
chemical_list: D003300:Copper