Base charge

Pentaerythritol tetranitrate is a high energy explosive that is used as a pressed base charge in blasting caps and detonators, as the core explosive in commercial detonating cord, and as the main explosive ingredient in sheet explosives. It is also mixed in various proportions with TNT to form the less sensitive pentoHtes, eg, PETN 50/TNT 50. PETN is easily initiated, its responses are reproducible, and it is readily available (144—146). 

Tetiyl. 2,4,6-Trinitrophenylmethylm tramine (tetryl) was used ia pressed form, mostly as a booster explosive and as a base charge ia detonators and blasting caps because of its sensitivity to initiation by primary explosives and its relatively high energy content. Properties are presented ia Table 11 (173). Batch and continuous processes for the production of tetryl have been developed. Tetryl is no longer used ia the United States and has been replaced by RDX (174-178). 

Grund-lack, m. base coat, base varnish or lacquer, -ladung, /. Expl.) base charge, -lage,/. foundation, groundwork, base basis, principle matrix basement Old Chem.) radical base. 

According to Branchini et al. (2004), luciferase modulates the emission color by controlling the resonance-based charge delocalization of the anionic keto-form of oxyluciferin in the excited state. They proposed the structure C5 as the yellow-green light emitter, and the structure C6 as the red light emitter. 

It is an expl, more powerful than TNT (about 133% by Ballistic Mortar), and comparable to Tetryl in sensitivity. Its Vel of Deton is 7420 m/sec at d 1.5g/cc, and 5490m/sec at d l.Og/cc. Qc is about 380kcal/mole. It is practically non-hygroscopic and its thermal stability is satisfactory. Has been used by DuPont Co as a base charge for some detonators Refs I) Beil — not found 2) H. Biltz et al, JPraktChem 142, 193-200 (1935) CA 29, 3652 (1935) 3) Anon, Report on Nitro-... 

In general terms, PETN can be characterized as a sensitive , brisant, and powerful high expl. Explosive sensitivity is a rather nebulous quantity, but there can be no doubt that PETN is a much more sensitive material than TNT, but rather less sensitive than Lead Azide. In particular, PETN requires very little priming i charge (less than 1 mg LA) to initiate its detonation. This is the characteristic that makes PETN so widely used in blasting cap base charges, in detonating cord and in boosters... 

The base charge of stab detonators had usually been Tetryl but present designs use RDX... 

In many investigations of CT, pendant redox probes interact with both bases of abase pair. However, studies of base-base charge transfer can differentiate between discrete intra- and interstrand reactions (Fig. 7). These investigations further attest to the critical role of base stacking in DNA-mediated CT. In B-DNA duplexes, stacking interactions are largely restricted to... 

For both technical and economic reasons, current detonators contain a base charge of high explosive which provides the main initiating power of the device. The most satisfactory high explosives for use as base charges are PETN, tetryl and RDX, and of these the first is by far the commonest, because of its sensitiveness and relatively low cost. 

Use of a narrower diameter tube. This leads to a longer length of base charge which in general is more effective in initiating blasting explosives. 

Increasing the thickness of the metal of the tube. Within limits this gives greater confinement and therefore more effective detonation of the base charge. 

In practice detonators of increased strength are made by increasing the weight of the base charge rather than by other means. The only important exception to this is the German Briska detonator (see p. 103). 

Assembly commences with a plain detonator containing its base charge and initiating explosive. These detonators are held in plates and the processes are insertion of suitable delay elements, followed by pressing in the normal way. They are then checked by X-ray examination to ensure... 

According to Sutton, cast double base charges are likely to contain 45-55% nitrocellulose, 25—40% nitroglycerine, 12-22% plasticiser and 1-2% other ingredients such as stabilisers. Typical properties are ... 

Base charge. In a detonator, the charge of high explosive which makes the major contribution to the power of the device. 

Briska detonator. A detonator in which extra power is achieved by extremely heavy pressing of the base charge. 

Induction time. In firing electric detonators, the time between the breaking of the fuse wire and the detonation of the base charge (see p. 112). 

Tetryl (C7H5N508) is a pale yellow crystalline solid. It is moderately sensitive to initiation by friction and percussion and is used in the form of pressed pellets as primers for explosive compositions that are less sensitive to initiation. It is slightly more sensitive than picric acid and considerably more sensitive than TNT. In the early 1900s, tetryl was used as base charges for blasting caps but now has been replaced by PETN and RDX. During World War II, tetryl was used as a component of explosive mixtures. 

Detection — Primarily via fluorescence-based charge-coupled device (CCD) camera detectors. 

Pentaerythritol tetranitrate (PETN) (3) is a powerful explosive which exhibits considerable brisance on detonation (VOD 8310 m/s at = 1.77 g/cm ). It is the most stable and least reactive of the common nitrate ester explosives. The relatively high sensitivity of PETN to friction and impact means that it is usually desensitized with phlegmatizers like wax and the product is used in detonation cord, boosters and as a base charge in detonators. Pentaerythritol tetranitrate can be mixed with synthetic polymers to form plastic bonded explosives (PBXs) like detasheet and Semtex-IA. A cast mixture of PETN and TNT in equal proportions is known as pentolite and has seen wide use as a military explosive and in booster charges. The physical, chemical and explosive properties of PETN commend its use as a high explosive. 

A similar approach was used in grafting Cjq onto a pregenerated lithiated polyethylene surface [121]. A polyethylene film with terminal diphenylmethyl groups was deprotonated with BuLi to yield an anionic polyethylene surface that was treated with Cg0 and quenched with methanol. The incorporation at the polyethylene surface was determined by XPS, UV/Vis and fluorescence spectroscopy. This reaction also works for polyisopropene, polybutadiene [69], poly(vinylbenzyl chloride) or poly(N-vinylcarbazole) PVK [54] with BuLi or NaH as a base. Charge-transfer interactions in the soluble fullerene-PVK derivative between the positively charged carbazole and Cjq lead to an enhanced photoconductivity compared with PVK [54]. 

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