Delay detonator types

The calculation of p-process yields from a variety of Chandrasekhar mass Type I supernova models of the deflagration or delayed detonation types, as well as of sub-Chandrasekhar He-detonation models. In the latter case, a... 

A real advance in the construction of delay detonators was made by Eschbach, who introduced delay compositions which evolved so little gas that there was no longer need to vent the detonator. This eliminated risk of pre-ignition of high explosive and also made it possible to provide fully waterproofed assemblies which gave delay times much more regular because of the removal of variable venting effects. Delay detonators of this type have now virtually superseded all others. 

Gasless delay detonators are manufactured to fire after pre-arranged delay times, each manufacturer providing a series of detonators with intervals of usually 1 s or 0.5 s. More recently a further type of delay detonator has been introduced, usually known as the millisecond, or short delay detonator. Again, manufacturers provide a series of fixed delay times, but in this case the interval between each number of the series is much shorter and may be from 25 to 50 ms. 

A type of British "electric delay detonator with an intermediate charge" is described in Ref 36, p 70 and is shown here as Fig 10. 

An other type of British nonmilitary electric detonator, called short type delay detonator" is described in Ref 36, pp 72-3 and is shown here in Fig 11. This detonator con-... 

A cylindrical extension housing the booster (with 38.2 grains of Tetryl), projects from the base of the fuze body. Its overall length is 16.4-in, wt 10.5-lb, and diam of its widest part is ca 3-in. It is detonator-safe, delay-armed type arming after 110 0-ft of air travel and functions upon impact thru two independent trains of 0.08-sec delay. The fuze is used in armor-piercing bombs to allow penetration of the target before detonation... 

In Table E5, p E28 of Vol 5 are given electrical characteristics of US Electric Bridge Type Delay Detonators XM60, T65 and T68 and compns of their spot, primary and secondary (base) charges... 

Metal-poor stars Spectral-line comparisons of Cu and of Fe in stars show that the Cu/Fe abundance ratio increased by a factor near 5 while the metallicity of the Galaxy grew during the first billion years. The cause lies either in the increasing yield of Cu from massive stars as they become more metal rich, certainly their s-process component, or in the onset of Type la delayed detonations after the earlier galactic epoch ofType II supernovae only. 

The relative importance ofiype la supernovae for Cu nucleosynthesis remains uncertain because it depends on the type of dynamic model chosen to explain the Type la explosion, and itis still notknown which type, if either, is correct Deflagration models account for less65 Cu than Type II supernovae but delayed detonation models account for more. 

An impressive progress has been done in multidimensional calculations of thermonuclear explosions of degenerate dwarfs for type la supernovae. It is still however unclear whether pure deflagration or delayed detonation is at work in SN la. The important problem is to more precisely determine the initial ignition conditions. Detailed radiation hydrodynamic modeling revealed that SN la light curves proved to be very sensitive to the explosion models and thus can be used to check the models. 

It is also possible that more use will be made in the future of electronic delays containing no pyrotechnic delay component, particularly in more sophisticated devices. These electronic delays should provide higher precision and avoid the manufacturing variability that is inherent with the production of pyrotechnic devices. Delays of this type have already been introduced in commercial blasting detonators to achieve improved blasting results via precise delay intervals (for more information, do a web search for the term electronic delay detonators). 

Detonators are used to detonate high explosives. Stab detonators are initiated by sharp firing pins and are used in explosive trains of different types of fuses. Flash detonators are initiated by flames produced by safety fuses, primers, or delay elements. A special type of flash detonator ignited by the flame of a safety fuse is called a blasting cap. Detonators are primarily composed of three types of explosives including sinoxid mixtures, lead azide-based mixtures, and mercury fulminate-based mixtures. 

Delayed-, After-, or Post-Reactions in Detonation. There are two general types those which occur within a confined space such as in a closed bomb, and those which involve reaction with external air and are known as "afterburning". Accdg to classical one-dimensional detonation theory, chemical equilibrium is achieved and reaction ceases at the CJ (Chapman-Jouguer) plane, which terminates the reaction zone. In some cases, however, as noted by Craig (Ref 3, p 863), the sharp shock wave and the reaction zone of falling pressure are followed by a further rapid pressure drop which is not predicted by an extrapolation of the one-dimensional theory... 

In these tests NMe showed the detonation-to-shock and shock-to-detonation transition characteristic of a homogeneous expl even with barriers as thin as 25fi- The reaction zone had a peak of probably less than 1 Ofi thickness. Nonporous 60/40-RDX/TNT was less sensitive to disturbance by thin barriers than NMe. A 250/r thick barrier could cause a disturbance in the reaction, but there was no delay and very little overshoot of the type usually associated with homogeneous expls. Experimental arrangements shown in Figs 1, 2, 3, 4 and 6 are not reproduced here... 

Concussion Detonator Ml, Delay Type is a mechanical firing device actuated by the concussion wave of a nearby blast. It fires several charges simultaneously without connecting them by wires or detonating cord. A... 

---