High Explosions

The pressure P is generally defined as a function of relative volume and internal energy. Assuming Fi t) is the final surface load, the pressure P must replace Fi t) in relevant equations by taking into consideration the surface volume on which it acts. All equations defining relevant detonation pressures P must first be evaluated. They are then first applied as stated, in Eqs. (3.13), (3.14), (3.15), (3.16), (3.17), (3.18), (3.19), (3.20), and (3.21). 

The cause of explosions can be nuclear (air burst or underground). The pressures, which are time dependent, can then act as surface loads on the body of the element concerned or at nodal points of the element as concentrated loads derived on the basis of shape functions. It is essential to choose a proper time-aspect ratio as it will affect the type of solution procedure adopted. The interaction between the loads and the structure can be considered and the method shown in Section 3.5 must be included. 

---

High explosives. Those explosives which normally burn without undue violence when ignited in an open space, but which can be detonated by a sufficiently large sudden mechanical or explosive shock. 

It is prepared by the direct nitration of toluene with a mixture of nitric and sulphuric acids. TNT is a very stable, violent and powerful high explosive, but less sensitive to shock and friction than picric acid. It is widely used as a filling for shells, bombs, etc. often mixed with ammonium nitrate and other high explosives. The lower grades of TNT may contain isomers which under hot storage conditions may give rise to exudation. 

Chen S, Hong X, Hill J R and DIott D D 1995 Ultrafast energy transfer in high explosives vibrational oooling J. Phys. Chem. 99 4525-30... 

Chen S, Tolbert W A and DIott D D 1994 Direot measurement of ultrafast multiphonon up pumping in high explosives J. Phys. Chem. 98 7759-66... 

When chlorine gas is in excess a highly explosive substance, nitrogen trichloride, NCI3, is formed ... 

Picric acid is used on a large scale as a high explosive, but for this purpose requires a detonator. If a few small crystals of the pure acid are heated on a crucible lid, they first melt, and ultimately burn harmlessly with a smoky flame. Metallic salts of picric acid are much less stable than the free acid,... 

CAUTION. Ethers that have been stored for long periods, particularly in partly-filled bottles, frequently contain small quantities of highly explosive peroxides. The presence of peroxides may be detected either by the per-chromic acid test of qualitative inorganic analysis (addition of an acidified solution of potassium dichromate) or by the liberation of iodine from acidified potassium iodide solution (compare Section 11,47,7). The peroxides are nonvolatile and may accumulate in the flask during the distillation of the ether the residue is explosive and may detonate, when distilled, with sufficient violence to shatter the apparatus and cause serious personal injury. If peroxides are found, they must first be removed by treatment with acidified ferrous sulphate solution (Section 11,47,7) or with sodium sulphite solution or with stannous chloride solution (Section VI, 12). The common extraction solvents diethyl ether and di-tso-propyl ether are particularly prone to the formation of peroxides. 

Organic peroxides are highly explosive, hence it is best to carry out the ozonisation in a solvent which dissolves both the original compound and the ozonide. 

The usefulness of the procedure described above is demonstrated inten alia by the fact that even highly explosive hexatriyne, HC=CC=CC=CH, can be isolated in almost 90", yield from the reaction of ClCH2CECCECCH2CI with KO-tert.-CijHq in THF (see Chapter V, Exp. I7). 

Note 4. The compound is highly explosive in a concentrated state. Heighing of the still cold receiver should be carried out without delay. 

Soil. Composting of soils contaminated by high explosives is being carried out at the Umatilla Army Depot near Hermiston, Oregon (70). Soil from munitions washout lagoons is being treated iadoors ia compost rows of 2,000 m, and the estimated cost is less than one-third the estimated cost of iaciaeration. If this is successful, there are 30 similar sites on the National Priority List that could be treated ia a similar way. 

Table 3. Comparison of Pyrotechnic Compositions with High Explosives ...

Explosives are commonly categorized as primary, secondary, or high explosives. Primary or initiator explosives are the most sensitive to heat, friction, impact, shock, and electrostatic energy. These have been studied in considerable detail because of the almost unique capabiUty, even when present in small quantities, to rapidly transform a low energy stimulus into a high intensity shock wave. 

Picric Acid and Ammonium Picrate. Picric acid (PA) (2,4,6,-trinitrophenol) was the first modem high explosive to be used extensively as a burster ia gun projectiles. It was first obtained by nitration of iadigo, and used primarily as a fast dye for silk and wool. It offered many advantages when compressed, it was used as a booster for other explosives, and when cast (melting poiat 122.5°C) served as a burster ia shell it was stable, iasensitive, nonhygroscopic, relatively nontoxic, and of high density when cast, and could be made economically by simple nitration. 

Ammonium picrate (AP) is used only where a high explosive is required that is particularly iasensitive to shock. It has been employed ia pressed form primarily as a burster ia aaval projectiles for armor peaetratioa. The compouad is very stable and does not form sensitive metallic salts. Its explosive... 

Explosive Detonation pressure, GPa Bulk specific gravity Detonation velocity, km/s Contains high explosives Heat of detonation kj /g Excavated vol relative to equal wt of TNT... 

M. A. Cook, S cience of High Explosives, Reinhold Publishing Corp., New York, 1958. 

A. O. Long, Viscosities of Some Castable High Explosives, NAVORD 2910, Washington, D.C., 1953. 

Y. O. Dova, The Chemistry and Technology of High Explosives, Wright Patterson Air force Base Translation, Dayton, Ohio, 1961. 

C. D. Hutchinson and co-workers, "Initiation and Detonation Properties of the Insensitive High Explosive TATB/KEL-F800 95/5," Vol. 1, in... 

Study of Insensitive High Explosives and Propellants," in Proceedings of Conference USDRC E 79-653, Mar. 1979. 

R. D. Lynch and co-workers, "Characteri2ation of Insensitive High Explosives Developed with Propellant Technology," in Proc. 1990JANNAF Propulsion Meeting VIII, 3-5 CPIA Pubhcation 550, CPIA, Laurel, Md., Oct. 1990, pp. 3—5. 

S. Fordham, High Explosives and Propellants, 2nd ed., Pergamon Press, New York, 1980. 

The production of hexamethylenetetramine consumes about 6% of the U.S. formaldehyde supply (115). Its principal use is as a thermosetting catalyst for phenoHc resins. Other significant uses are for the manufacture of RDX (cyclonite) high explosives, in mol ding compounds, and for mbber vulcanisation accelerators. Some hexamethylenetetramine is made as an unisolated intermediate in the manufacture of nitfilotriacetic acid. 

The predetonation distance (the distance the decomposition flame travels before it becomes a detonation) depends primarily on the pressure and pipe diameter when acetylene in a long pipe is ignited by a thermal, nonshock source. Figure 2 shows reported experimental data for quiescent, room temperature acetylene in closed, horizontal pipes substantially longer than the predetonation distance (44,46,52,56,58,64,66,67). The predetonation distance may be much less if the gas is in turbulent flow or if the ignition source is a high explosive charge. 

---