Low and High Explosives

Ohart (Ref 17, p 20) gives a diagram of elements of explosive trains, both of low-and high-explosive, which are reproduced here as Fig l-21a... 

In Fig l-21b is shown a complete explosive train (comprising both low- and high-explosive trains) in fixed round of artillery ammunition... 

A comprehensive review includes autoignition of gas mixtures, explosions at low and high temperatures, properties of flames and combustion of metals [1]. A review of explosion suppression techniques for dust, mist or vapour deflagrations, as an alternative to venting industrial plant [2],... 

Figure 13.7 Electropherograms showing the simultaneous measurement of low- and high-energy explosives as recorded with the (a) conductivity and (b) amperometric detectors. Analytes, ammonium (1), methylammonium (2), sodium (3), TNB (4), TNT (5), 2,4-DNB (6), and 2-Am-4,6-DNB (7), system peak (SP). Explosive concentration, 2 mM (1,2,3) and 15 ppm (4,5,6,7). Conditions MES/His buffer (20 mM, pH 6.1) containing 15 mM lithium dodecyl sulfate as the run buffer separation field strength, +250 V/cm injection field strength, +250 V/cm for 2 s detection at 200 kHz, (a) 5 Vp p and at (b) —0.5 V. (Reprinted in part with permission from [34]. Copyright 2002 American Chemical Society.)...

The original classification of explosives separated them into two very general types low and high, referring to the relative speeds of their chemical reactions and the relative pressures produced by these reactions. This classification still is used but is of limited utility because the only low explosives of any significance are black powder and smokeless powder. All other commercial and military explosives are high explosives. 

An igniting or explosive device in form of a cord, consisting of a flexible fabric tube and a core of low or high explosive. Used in blasting and demolition work, and in certain munitions. A fuse with a black powder or other low explosive core is called a safety fuse or blasting fuse. A fuse with a - PETN or other high explosive core is called detonating cord or primacord. 

Explosives were originally classified into two main types low and high. This classification was based on the relative detonation speeds and the pressures produced by these reactions. Low explosives bum very rapidly and generate pressures below 50,000 psi. However, high explosives produce pressures of 5 million psi. The detonation rate of explosives has been characterized by comparing it with the speed of sound. High explosives are faster than the speed of sound, whereas low explosives detonate at a lower rate than the speed of sound. This classification is of limited use in this century and thus explosives have been classified in relation to their chemical nature and to their performance. The explosives have been divided into three classes (Fig. 12.2) [4, 5] ... 

DADNE is a relatively new, low sensitive high explosive developed by the Swedish Defence Research Agency FOI. It is insoluble in cold water, slightly soluble in acetonitrile and cyclohexanone, soluble in DMSO, dimethylformamide and N-methylpyrrolidinone. Besides, it can cause allergic skin reactions. 

In essence, an explosive is a liquid or solid material, or a mixture of liquid and solid materials, that is very rapidly converted to a gas or gasses by the application of heat or a sharp blow. There are two main classes of explosives "low" and "high."... 

Explosives are materials that combust at an extremely fast rate to form a pressure-shock wave. Explosives can be classified into two groups low explosives, with pressure waves traveling at less than 3,300 feet per second (fps), and high explosives, with transonic shock waves (>3,300 fps). 

LC is usually performed at room temperature. Thus, it is suitable for analysis of all kinds of compounds organic and inorganic compounds, compounds of low and high molecular mass, and labile compounds such as explosives and stable compounds. The conventional CC and planar techniques do not require the use of expensive instruments. HPLC competes with GC in precision and effectiveness. However, the reproducibility is usually lower. If necessary, a high reproducibility is obtained with more precautions. 

Acoustic hazards low and high frequency noise, ultrasound, explosive waves, thunder. 

A whole range of explosives is available to the quarry engineer. It extends from powder to gelatinous explosives and includes slurry explosives there are low explosives and high explosives, as well as intermediate types explosives which are used in cartridge form and those which are used in bulk. Careful consideration of the choice of explosive, so that the most su itable type for the job is used, makes for greater economy. 

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