Explosive determination

Photoionization, where electrons are released by molecules following the absorption of energy from photons, has long been viewed as a non-radioactive means to ionize explosives in the vapor phase [39]. In recent years, two teams have sought to employ laser ionization with IMS for explosive determinations. A team at Implant Sciences Corporation has utilized a laser (or flash lamp) for sampling surfaces and for ionization of sample vapors in an IMS analyzer [40, 41]. In their approach, the sample is removed from a surface with an increased temperature from laser exposure. Gases (and presumably particulate matter) from over the surface are drawn into an IMS drift tube using a wall-free inlet vida supra). In the IMS drift tube, resonance multi-photon ionization by a laser is used to produce ions from the explosives. Their... 

With a focus on trace forensic detection of explosives, especially for use in counterterrorism and to counter narcotics investigations, Fetterolf et al. [75] evaluated the use of ion mobility-mass spectrometry for explosives determinations. In this, explosives residues were collected on a membrane filter by a special attachment on a household vacuum cleaner. Although subsequent thermal desorption and analysis required only 5 s, fimits of detection for most common explosives were as low as 200 pg. The persistence of explosives on hands and transfer to other surfaces were also examined as were post-blast residues of NG on fragments of improvised explosive devices constructed with double-based smokeless powder. Finally, postblast residue from C-4, Semtex, and other explosives was found by IMS analyses on items of forensic and evidentiary value. These few out of many examples demonstrate that mobihty spectrometers are well suited tools for laboratory and on-site investigations, before and after the use of explosives. 

Power of Explosives Determination. The tests and refs are listed in Vol 1, p XX. 

Strength of Explosives, Test. See Vol 1, p XXIV and under Power of Explosives Determination... 

Volume of Gases Evolved on Detonation (or Explosion), Determination. See Vol 1, p XXVI... 

Heat of Explosion Determination (1286—88) Hygroscopicity of Propellants (1288—89) Moisture by the Carbon Tetrachloride Distillation Procedure (1289—90)... 

The explosive properties of dinitrochlorohydrin are as follows. The heat of explosion determined by Naoiim [8] in a calorimeter bomb (water in the liquid state, hydrogen chloride as hydrochloric acid) is 1140 kcal/kg. This value corresponds to a heat of explosion of 1000 kcal/kg when water and hydrogen chloride are assumed to be in the gaseous state in agreement with the equation given by Naoiim ... 

Explosives determination with a micro-fabricated differential mobility spectrometer... 

In routine testing the temperature corresponding to a given ignition delay is generally reported. Table 1 shows such temperatures for various azides and ignition delays. Table II hsts the explosion temperatures of a number of azides for a 5-sec ignition delay, calculated from the data of Wohler and Martin [15]. Also hsted are the minimum temperatures that result in explosion, determined... 

K. The plant manager is vi rried about the possibility of explosion. Determine the energy released by a sudden rupture of this storage tank and the temperature and physical state of the methane immediately after the rupture. ... 

The chemical stmctures and physical states of explosive determine whether they explode or not. But, to some degree, different explosives are different in amount of released energy, reaction speeds, and gas productions. In general, explosion reactions must have the three key features exothermicity, rapidity, and gas productions. This is applied for all explosions. 

The work capacity of explosives determines damage of explosion. They are different following the change of explosive, packed mass, the surrounding media. And the damage is also different if the distance to the explosion center varies. 

The induction time is the time elapsed between initiation (by the laser pulse in this case) and the explosion (determined by the maximum intensity of the emitted light). 

The sensitivity to detonation of an explosive is determined by the ease with which the explosive can be ignited by the primary detonation or another explosive in the vicinity which generates a shock wave. A maximum gap between the initiated detonator and the test explosive determines the sensitivity of the explosive to detonation. This gap test is an important characteristic which is usually... 

Fig. 2.18 Impact sensitivity of various primary explosives determined as number of positive trials out of five at specific drop heights (KDNBF-potassium salt of 4,6-dinitrobenzofuroxan, for other abbreviations see previous text) [40]...

Boron-doped diamond presents another attractive material with low and stable background current and noise over a wide potential range, corrosion resistance, high thermal conductivity, and high current densities. Usually no mechanical or electrochemical pretreatment of BDD film electrode is needed. Therefore, BDD film electrodes find use also in the area of environmental analysis for organic explosive determinations. BDD-based electrochemical detector allowed, e.g., amperometric detection of 2,4,6-trinitrotoluene, 1,3-dinitrobenzene, and 2,4-dinitrotoluene over the 200-1,400 ppb range, with detection limits at the 100 ppb level. ... 

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