Ordinary detonators

One of the characteristics of m- dinitrobenzene is that it shows an exceptionally low sensitivity to impact and friction. For this reason attempts have been made to use it in armour-piercing shells. However they have failed due to its two serious disadvantages namely its great toxicity and the difficulty of effective complete detonation by initiation with an ordinary detonator. Thus, m- dinitrobenzene, even when compressed to a density of 1.44, requires an additional, secondary detonator. 

Two crystallographic forms of lead azide are important, the ordinary alpha form which is orthorhombic and the beta form which is monoclinic. The densities of these forms are 4-71 and 4-93 respectively. It was for many years believed that the beta form is the more sensitive to friction and impact and accounted for detonations which have occurred in the manufacture and handling of the substance. It is now known that the beta form is in fact no more sensitive than the alpha. Even the alpha form, when present as large crystals, is very sensitive and conditions can arise (particularly when the formation of the lead azide is controlled by diffusion effects) where spontaneous detonation occurs. Although with modern knowledge these hazards can be avoided, pure lead azide is nevertheless a dangerous compound and is now made only for military purposes. 

Detonating fuse is made by either a dry process or a wet process. The former is generally more popular because of its lower costs for ordinary types of fuse. The latter is, however, used particularly in North America. 

Detonations produce much higher pressures than what be considered ordinary explosions. In most cases a process vessel or piping systems will be unable to contain detonation pressure. The only safe procedure is to avoid process system detonations is to preventing the formation of flammable vapor and air mixtures within vessels and piping systems. While the flame speed of explosions is at relatively slow speed, detonations travel at supersonic speeds and will be more destructive. 

Nitromethane is a detonable explosive, nitroethane can be detonated if both hot and under strong confinement, other nitroalkanes are mild oxidants under ordinary conditions, but precautions should be taken when they are subjected to high temperatures and pressures, since violent reactions may occur [1], Explosives are described consisting of nitromethane stabilised for transport by admixture with nitroethane or nitropropane, then resensitised by addition of an amine [4], The polynitroalkanes, being more in oxygen balance than the mono-derivatives, tend to explode more easily [2], and caution is urged, particularly during distillation [3], See also POLYNITROALKYL COMPOUNDS... 

Original studies of gaseous detonations have shown no single sequence of events due primarily to what is now known as the complex cellular structure of a detonation wave. The primary result of an ordinary thermal initiation always appears to be a flame that propagates with subsonic speed. When conditions are such that the flame causes adiabatic compression of the still unreacted mixture ahead of it, the flame velocity increases. According to some early observations,... 

A bomb can be considered to contain four functional blocks, namely, a control system, a detonator, a booster, and a main charge. Although a simple ignition fuse can be used as a control system and timing device, the control system is usually more mechanical or electrical in nature. The detection of control systems may be visual, or by magnetometry, or by X-ray. It must be remembered that many of the items involved in the ignition system, that is, clockwork, batteries, or electronic circuitry, are commonplace in ordinary items, such as cameras, mobile telephones, and personal stereos, and are not unique indicators of the presence of a bomb. In fact, it is the presence of explosives that is the key indicator of a bomb. 

Hydrogen is a flammable gas. It combines explosively with oxygen at ordinary temperatures in the presence of finely divided metals. The LEL and UEL are 4 to 74% by volume in air, respectively. It combines with halogens explosively. Explosion of its mixture with chlorine is detonated by sunhght, heat, or a spark. 

In 1758-59 A. S. Marggraf prepared very pure cubic saltpeter from common salt. After cooling the vessel and breaking the retort, said he, I found m it a saline substance which took fire on glowing charcoal, without the slightest crackling (just as ordinary saltpeter does when very pure) and, as the chemists say, detonated, but with the difference that the flame was yellow for that with ordinary prismatic niter is usually whitish (48). In his next paper, which was entitled Proof that the alkaline part separated from common salt is a true alkaline salt and not an alkaline earth, he mentioned the yellow flash of gunpowder made with cubic saltpeter and the blue (violet) flash of that made with prismatic saltpeter (48). 

In an "ideal one-dimensional detonation, the expansion of the products behind the C-J plane forms a "rarefaction wave , of which the head pursues the detonation front but cannot overtake it because the wave is moving at sonic velocity in the products and they are receding from the front at just that velocity (Ref 2, pp 200-02). In an ordinary cylindrical charge (Ref 2, pp 204-06), the shape of the detonation head depends on two types of rarefactions one from the rear, corresponding to the stag-... 

A. Grib, Prikladnaya Mat.ematika i Mekhanika 8, 169 (1944) (On the propagation of a plane wave for an ordinary explosion near a plane wall) 12) S.J, Jacobs R.S. Grabenstetter, "Shaped Detonation Waves, OSRD 5603 (1946) 12a) K.O. Friedrichs,... 

Ordinary delay detonators in Gt Britain are issued in series numbered from 0 to 10, the interval betw any two consecutive delay numbers being 0.5 sec. Thus the No 0 fires instantaneously, No 1 fires 0.5 sec later, etc ( Ref 36, p 71)... 

Percussion Nose Fuze M40 with Detonator M40-Ordinary and Instantaneous for 75 to 100-mm projs (p 138)... 

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