Samples of Explosives

Barrier Tests and Their Comparison with Shooting Tests. In the shooting test, a cylindrical projectile of Al, steel, etc is shot against a cylindrical sample of explosive in such a manner that one of the plane surfaces of projectile strikes a plane surface of the expl sample. The pressure developed on coaxial impact can be calcd from the expression ... 

In the barrier test, a cylindrical sample of explosive is separated from a charge of expl known as donor by a harrier, which is a thick disk of Al, br ass or other metal. In this test, the donor creates a shock wave in the barrier, which in turn gives rise to an impact pressure at the contact surface... 

Analyses of unknown samples of explosives used in primers and detonators before WWII in the Laboratoire Centrale de Poudres, Paris, are described in Vol 1 of Encycl, p A580-R (Ref 18)... 

In the Kostevitch method a sample of explosive (about O.lg) is introduced into a small glass bulb (volume=ca 3.5cc), resembling in appearance that used for weighing fuming acids, but made from a larger diameter tube in order... 

Test No 2 A small sample of explosive is placed on an asbestos board and a small flame of a Bunsen burner is directed against it for 10 seconds. It is considered noninflammable if it does not ignite in this period. Control samples of known explosives should be included for comparison... 

Friction Test. A small sample of explosive rubbed in an unglazed porcelain mortar should not show greater sensitivity than PA at room temp... 

Note Before the centrifuge test was developed by Dr W.O. Snelling, the Bur of Mines used the pressure test for exudation, which consisted in exposing a sample of explosive to a definite pressure produced by the weight of a lever arm, and determining the amt of liquid forced out of the expl. Many modifications of this test have been tried, in which absorbent materials like cotton or blotting paper have been used to hold the exudant, but none of them made the test reliable (Ref 1, p9)... 

Brisance by Fragmentation Test. When using a malleable iron grenade container with a 16.5g sample of explosive, the bris-ance was found to be greater than that of TNT and somewhat greater than that of PA. (Ref 4,p 1390)... 

Kolia [32] used SPE and GC-TEA to prepare and analyse samples of explosives and found that SPE was the most useful way of reducing the contamination of the column by accompanying substances. The SPE columns were 500-mg RP18 (3 cm) columns. The original sample, whether dust or swabs, was extracted with acetone in a Soxhlet extractor. The acetone was then evaporated and the sample dissolved in acetone and diluted at 1 10 with water. After washing, the elution was performed with three volumes of methanol. After the methanol had been evaporated, the sample was dissolved in a small volume of acetone for GC-TEA. 

Hankin et al. [133] demonstrated femtosecond ionization following 266 nm desorption of solid samples of trinitrobenzene (TNB), TNT, and trinitrophenol (TNP). They confirmed the advantages of ultrafast ionization, namely, the formation of characteristic precursor and structure-specific fragment ions. The optimum intensities for efficient LD without ionization were determined for the compounds studied. Differences between femtosecond ionization of vapor samples of explosives [131,132] and laser desorbed molecules were also discussed. 

A 0.7-g sample of explosive, 5-100 mesh, is exposed to the action of a steel or fiber shoe swinging as a pendulum at the end of a long steel rod. The behavior of the sample is described qualitatively, i.e., the most energetic reaction is explosion, and in decreasing order snaps, cracks, and unaffected. 

A 0.4-g sample of explosive, pressed at 3000 psi into a No. 6 cap, is initiated by lead azide or mercury fulminate (or, if necessary, by lead azide and tetryl) in a sand test bomb containing 200 g of on 30 mesh Ottawa sand. The amount of azide of Tetryl that must be used to... 

Sullivan RJ, Watson GW. 1983. Sampling of explosives with multiple, portable preconcentrating cartridges. In Proceedings of the International Symposium on the analysis and detection of explosives, FBI Academy, Quantico, VA, March 29-31, 1983. Washington, DC U.S. Department of Justice, Federal Bureau of Investigation, 431-440. 

It has been found that upon detonation, an explosive can cause a nearby sample of explosive to detonate sympathetically. The distance over which one charge can detonate another is a function of the amount of energy produced by the first explosion and the medium through which the shock wave is propagated to the second charge of explosive. For instance, the relationship for air (very approximately) would be expected to be weight of explosive in lbs/(distance in ft)3 = 4. Thus, to calculate the maximum distance for a possible sympathetic detonation of 40,000 lbs of explosive, the calculation is ... 

This test bridges the gap in the growth from thermal decomposition reaction to explosion and eventually involves fast oxidation reactions. A small sample of explosive is pressed into a blasting cap cup made of gilding metal. The cup is then inserted into a molten Wood s Metal bath. The time it takes from insertion in the bath until some noticeable reaction takes place (usually a mild explosion) is noted. The test is repeated at several different bath temperatures. See Table 6.3. A smooth curve is drawn through the data points (time to explosion versus bath temperature), and the temperatures that cause reaction in 1, 5, and 10 s are interpolated from the graph. 

R.W.Van Dolah. Electrostatic Spark Test on 9 Samples of Explosives , US BurMines Rept 3426 (Dec 1954) Project 2301- 185 15) R.E. Braid, R.C. Langille... 

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