Forensics Journal - Stevenson University 2012 | Page 8

STEVENSON UNIVERSITY

of identification that would provide a one-to-one correlation with a
known shoe. Smokeless powder is also of this classification. The third
consideration is association. Here the analysis demonstrates a relationship or connection between victim and scene, victim and suspect,
or suspect and scene. Ideally, the combination of a unique identifier
coupled with a positive association of the suspect to either the victim
or scene is sought. This would require the more costly instrumentation and therefore limit the abilities of some labs to perform the
examination.

in Figure 1.1. The discharge residue in this plume is now free to be
deposited on all exposed surfaces. This research focuses on the process of correlating a relationship between unfired smokeless powder
propellant, the OGSR residue found in spent cartridge casings at the
crime scene, and the OGSR residue on the hands or clothing of a
suspect. The most important correlation would be that of the residue
in the cartridge casing with the residue on the suspect. This provides
the key element of association to the crime scene.
As noted, the smokeless powder propellant used in small arms cartridge casings is also a source of GSR identification. Propellants may
be defined as “explosive materials which are formulated, designed,
manufactured, and initiated in such a manner as to permit the
generation of large volumes of hot gases at highly controlled, predetermined rates” (Kirk-Othmer Encyclopedia of Chemical Technology, 2nd ed, 2003). These propellants are a mixture of materials that
perform various functions in the design of the propellant. Some of
the most common functions are energizers [nitrocellulose (NC),
nitroglycerine (NG)]; stabilizers [diphenylamine (DPA), ethylcentralite (EC), N-nitrosodiphenylamine (N-nDPA)]; and plasticizers [dibutylphthalate (DBP), diethyl phthalate (DEP), 2, 4-dinitrotouluene
(2, 4-DNT), and either 2 or 4-nitrodiphenylamine (2 or 4-NDPA)
and 2, 4–dinitrodiphenylamine (2, 4-DNDPA)]. Plasticizers add
strength and flexibility to the propellant. Mach et. al. have found
1-mononitroglycerine (1-MNG) and 2, 6-DNT as contaminants in
smokeless powder formulations (Mach et. al., 1974). Others have
found that 1-MNG is a degradation product of NG (Martel et al.,
2005). These materials, when taken together, may have the potential
to identify a residue as having come from a smokeless powder source.
Different manufacturers add different additives in varying concentrations and forms based on the properties of the powder they wish to
control. This makes the smokeless powder composition unique to the
manufacturer and to the product marketed. It is this composition of
additives and energetic materials that leads to decomposition products that may be characteristic or particular to a certain manufacturer
(NRC, 1998). In this thesis, these materials will be referred to as
OGSR to distinguish them from the inorganic GSR particles.

The development of a method that would provide class identification
and similar association capabilities would also provide valuable evidence. I Ё