This study examines the sorption of explosives [TNT, RDX, PETN, TATP] to hair during exposure to their vapors. In each test, three colors of hair were simultaneously exposed to explosive vapor. Washing, extracting, and gas chromatographic quantification protocols were developed, and replication of quantitative data was confirmed. Results
show that sorption of explosives, via vapor diffusion, to black hair is significantly greater than to blond, brown or bleached hair. Furthermore, the rate of sorption is directly related to the vapor density of the explosive: TATP >>> TNT >> PETN > RDX. Using TNT as the prototype, persistence of the explosive upon standing in air and upon repeated washing with sodium dodecyl sulfate was demonstrated. This study indicates that hair can be a useful indicator of explosive exposure/handling. Work is in progress to develop this technique into an effective forensic tool.
Dogs have been used successfully to detect drugs and conventional high explosives. The world-wide rise in terrorist activities has placed emphasis on the detection of non-conventional explosive materials such as the multi-functional peroxides, triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD). This study demonstrates that dogs can detect both solid TATP and TATP adsorbed to cotton balls. An effective procedure to train dogs to detect TATP using cotton balls permeated with TATP vapor is provided. The various trials showed that dogs were capable of detecting as little as 200 μg of TATP adsorbed to a one gram cotton ball under a variety of circumstances. However, since TATP vaporizes rapidly at room temperature, significant depletion of TATP from cotton balls can occur in as little as 20 minutes, hampering the ability of the dogs to detect it. The TATP depleted cotton ball can be refreshed by returning it to a sealed container with TATP residue for about 20 minutes. A presumed decomposition product of TATP, acetone, cannot be used in place of TATP to train dogs.
The purpose of the Explosives Fate and Transport (EF and T) experiments is to define in detail the accessible trace chemical signature produced by the explosives contained in buried landmines. We intend to determine the partitioning, composition, and quantity of explosive related chemicals which emanate form different kinds of landmines buried in multiple soil types and exposed to various climatic events. We are also developing a computer model that will enable us to predict the composition and quantity of ERC under a much wider range of environmental conditions than we are able to measure experimentally.
The goal of the DARPA 'Dog's Nose' program is to develop a sensor capable of detecting explosives contained in all buried landmines. In support of the DARPA program, the purpose of the Explosives Fate and Transport experiments is to define in detail the accessible trace chemical signature produced by the explosives contained in buried landmines. We intend to determine the partitioning, composition, and quantity of explosive related chemicals which emanate from different kinds of landmines buried in multiple soil types and exposed to various climatic events. We are also developing a computer model that will enable us to predict the composition and quantity of ERC under a much wider range of environmental conditions than we are able to test experimentally.
Most explosive detection technologies have been focused on nitro-based military explosives becuase they have figured in international terrorist incidents. Not only are they readily available through purchase or theft or from sponsoring states, but methods for home synthesis are widely available. Many of explosive detection technolgies now under development target a specific characteristic of military or commercial explosives (e.g. mass density, nitrogen density). However, as counterterrorist measures make traditional explosives more difficult to obtain or more risky to use, we should anticipate terrorists may turn to nontraditional explosives. There are hundreds of energetic compounds and many common explosives which, while they do not meet exacting military demands, might be effective terrorist tools. Although explosive handbooks list hundreds of explosives, this talk focuses on only a handful. These have been chosen because they do not follow the classic patterns of military explosives or because they are easily obtainable. This paper will also point out energetic systems that can produce violently exothermic reactions without the aid of traditional initiating systems, such as batteries or detonators.
Most explosive detection technology has been centered on systems tuned to nitro-based explosives or on imaging devices with high X-Ray or other spectrometric profiles. There are, however, several readily available and highly effective non-nitrogenous high energy explosives which are essentially invisible to explosive detection technologies currently in development.
"Transparent" explosives which will be discussed in the first part of this presentation include peroxides (used in both monergolic and hypergolic applications); acetylene precursors; and fuel/air bomb systems involving use of olefin oxides, acetylene, other hydrocarbons, and similar high energy agents. For many of these, blasting cap or similar detonating devices requiring easily detected triggering systems are not required. Areas to be covered for these explosive systems include commercial availability or ease of clandestine manufacture (preparative schemes and raw materials); stabilities in transit; ignition/detonation systems; energy release; and potential for use in clandestine operations. Suggestions for enhancing airport detection will also be presented.
The second part of this paper will deal with numerous composite explosives in the form of intimate mixtures of condensed-phase fuels and oxidizers, which also could be formulated. Many of these rely on perchlorate, chlorate or hypochlorite salts as oxidizers. Several self-igniting systems such as boranes, phosphorus and alkali metals will be discussed as well.
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