Electric detonators spark sensitivity

Rate of Detonation. See Detonation Race Rifle Bullet Impact Test — not found Sand Test. See under Brisance Sensitivity to Electric Spark or to Electrostatic Discharge. See under Electric Spark Sensitivity to Initiation — not found Sensitivity to Pressure. When pressed at pressures in excess of 25000psi,. MF will... 

TNT, like RDX and Composition B, is not classified as dangerous with respect to hazard from electric sparks. Sensitivity to electrostatic discharge of TNT (thru 100 mesh) is 0,06 Joules (unconfined) and 4.4 Joules (confined) TNT can be detonated by electric discharge (Ref 108)... 

On the other hand, the characteristics of detonation, electric spark sensitivity, and thermal decomposition correlate with the N NMR chemical shifts of nitrogen atoms of the most reactive nitro groups. The basis of initiation by electric spark could lie in a thermal stimulus [35,39,52,53]. However, thermal stimuli cannot be considered in the process of detonation initiation by shock (also by impact) [115]. This also agrees with the finding that the detonation characteristics of energetic materials correlate with the characteristics of their low-temperature decomposition, which means that the primary fragmentation of polynitro compounds in their detonation transformation proceeds at milder conditions than those present at the front of detonation wave or in its reaction zone. That also means that the detonation transformation itself of the given substance should be preceded by an induction period [120]. 

The paper presents a brief survey of available results obtained from studies of the initiation micro-mechanisms of polynitro compounds from the point of view of organic chemistry. Attention is also paid to the basic mechanisms of low-temperature thermal deeomposition of these compounds. With consideration of these results, the relationships have been specified and analyzed between the characteristics of impact and electric spark sensitivities, detonation and thermal decomposition, on the one hand, and C and N NMR chemical shifts of polynitro compounds, on the other. In the ease of the impact sensitivity, the said relationships involve the NMR chemical shifts of the atoms carrying the most reactive nitro groups. In the case of the remaining stimuli studied, the N shifts of nitrogen atoms in the most reactive nitro groups themselves are involved. It has been stated that the chemical micro-mechanisms of primary fission processes of molecules of polynitro compounds in the initiation by mechanical stimuli (inclusive of the detonation course) and electric spark should be the same as in the case of their low-temperature thermal decomposition. 

The values of measurements carried out with the instrument RDAD were comparable with those of LANL in Los Alamos [ 174], In the papers [ 175,176] the electric spark sensitivities of 23 polynitro arenes and 13 nitramines were determined as the spark energy, E s, required for 50 per cent initiation probability. The relationship between the es values and the squares of detonation... 

Fig. 25 Graphical representation of the E-P-S relation (Eq. 10) between the electric spark sensitivity and the square of the detonation velocity for compounds which thermolyze via a five- or six-membered transition state involving a direct participation of an orf/io-nitro group (Schemes 2 and 3b) [ 175]...

Xiao et al. [179], using the DFT-B3LYP6-31G approach, re-evaluated the results of [175-177] for nitramines. They confirmed the linear relationship between and es values and, in addition, specified another linear relationship between the logarithm of detonation pressure and es values. Both relationships show, that increasing performance is coimected with increasing electric spark sensitivity in technologically attractive nitramines [179]. 

The relationships between detonation characteristics of energetic materials and characteristics of their low-temperature decomposition and other characteristics of their mechanical and electric spark sensitivities [6-9,16, 60,89,98,118,145,146,148,153,155,159,169,170,172,175-178] means that ... 

Primary explosives differ from secondary explosives in that they undergo a rapid transition from burning to detonation and have the ability to transmit the detonation to less sensitive (but more powerful) secondary explosives. Primary explosives have high degrees of sensitivity to initiation through shock, friction, electric spark, or high temperature, and explode whether confined or unconfined. Some widely used primary explosives include lead azide, silver azide, tetrazene, lead styphnate, mercury fulminate, and diazodinitrophenol. Nuclear weapon applications normally limit the use of primary explosives to lead azide and lead styphnate. 

Lead styphnate is a fairly weak primary explosive. Th is material must always be used with a sensitive booster charge. The main advantage of this material that it is very easy to det on ate with a spark. A thin layer of lead styphnate is often used as an initiator for lead azide. The ease with which this material may be detonated makes it quite sensitive to static electricity discharge. 

The most sensitive of the military explosives classed as primary explosives. In a finely divided state, it is as sensitive as mercury fulminate. Veiy sensitive to heat, shock, and friction. Sharp blows or metal-on-metal friction is sufficient to cause detonation. Readily detonated by bullet impact and may be ignited by sparks. Not normally ignited or detonated by static electricity generated on the body or in routine handling. Extremely sensitive to ignition by lead azide but not from the spit of a fuze. Very insensitive to flame, shock, and friction in primacord so must be detonated by cap. Does not detonate under long, slow pressure. 

One of the ways of specification of this mechanism can lie in study of relationships of the said sensitivity of energetic materials to their molecular structure [32], thermal reactivity [35,39,52,109-111], sensitivity to mechanic stimuli [32,109,112,113] and detonation characteristics [5,33,34,47]. As already stated, a thermal stimulus could be the basis of electric spark initiation [35,39,52,53],... 

The homol3d ic fragmentations or reactions of the C-NO2, N-NO2, N-NO, and O-NO2 groupings, or other bearers of explosibility (i.e. explosophores), are common primary fission processes of energetic materials under thermal [1-18], impact [1,3,4,6,16,19-27], shock [1,6,18,19,20,24,26-32] and electric spark stimuli [5, 32-36]. Therefore, it is natural that relationships exist between characteristics of low-temperature thermal decomposition and impact [6,37,38] or electric spark [35,39,47] sensitivities and also detonation characteristics [26,40-48,50] of pol3mitro compounds. 

Explosive solids can be detonated by heat, mechanical impact, friction, or electrical spark or discharge. The sensitivity of an explosive is the effect of the stimulus on its spontaneous detonation ... 

Primary explosives are sensitive mixtures/compounds that can be easily detonated by an SII— nonexplosive means such as flame, heat, impact, friction, electric spark, etc. They are mainly used in apphcations where it is desired to produce shock for initiation of a less sensitive explosive (secondary explosive). The ability to initiate detonation of secondary explosives is the characteristic that makes primary explosives useful in detonators and blasting cups or caps (detonators used for mining). In order for this to work, primary explosives must detonate shortly after the nonexplosive initiation. The fast transition from SII to detmiation (sometimes referred to as acceleration) is the most important distinction between primary and secondary explosives. 

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