Bomb blast effects

The term
TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. The "ton of TNT" is a unit of energy defined by that convention to be 4.184 gigajoules, which is the approximate energy released in the detonation of a metric ton (1,000 kilograms or one megagram) of TNT. The convention intends to compare the destructiveness of an event with that of conventional explosives, of which TNT is a typical example (although other conventional explosives such as dynamite contain more energy).

The "kiloton (of TNT)" is a unit of energy equal to 4.184 terajoules.

The "megaton (of TNT)" is a unit of energy equal to 4.184 petajoules.

The kiloton and megaton of TNT have traditionally been used to describe the energy output, and hence the destructive power, of a nuclear weapon. The TNT equivalent appears in various nuclear weapon control treaties, and has been used to characterize the energy released in such other highly destructive events as an asteroid impact.

The explosive yield of a nuclear weapon is the amount of energy released when that particular nuclear weapon is detonated, usually expressed as a TNT equivalent (the standardized equivalent mass of trinitrotoluene which, if detonated, would produce the same energy discharge), either in kilotons (kt—thousands of tons of TNT), in megatons (Mt—millions of tons of TNT), or sometimes in terajoules (TJ). An explosive yield of one terajoule is 0.239 kt of TNT. Because the accuracy of any measurement of the energy released by TNT has always been problematic, the conventional definition accepted since the dawn of the Atomic Age is that one kiloton of TNT is simply to be 1012 calories equivalent, which is only approximately equal to the energy yield of 1,000 tons of TNT.

The yield-to-weight ratio is the amount of weapon yield compared to the mass of the weapon. The practical maximum yield-to-weight ratio for fusion weapons (thermonuclear weapons) has been estimated to six megatons of TNT per metric ton of bomb mass (25 TJ/kg). Yields of 5.2 megatons/ton and higher have been reported for large weapons constructed for single-warhead use in the early 1960s. Since this time, the smaller warheads needed to achieve the increased net damage efficiency (bomb damage/bomb weight) of multiple warhead systems, has resulted in decreases in the yield/weight ratio for single modern warheads.

Pre-Napoleonic
Gunpowder, also known as black powder, is the earliest known chemical explosive. It is a mixture of sulfur, charcoal, and potassium nitrate (saltpeter). The sulfur and charcoal act as fuels, and the saltpeter is an oxidizer. Because of its burning properties and the amount of heat and gas volume that it generates, gunpowder has been widely used as a propellant in firearms and as a pyrotechnic composition in fireworks. Formulations used in blasting rock (such as in quarrying) are called blasting powder. Gunpowder is mainly used in older guns now because the propellants used today are too powerful and could break the already fragile barrels.

Gunpowder was invented in the 9th century in China, and the earliest record of a written formula for gunpowder appears in the 11th century Song dynasty text, Wujing Zongyao. This discovery led to the invention of fireworks and the earliest gunpowder weapons in China. In the centuries following the Chinese discovery, gunpowder weapons began appearing in the Muslim world, Europe, and India. The technology spread from China through the Middle East or Central Asia, and then into Europe. The earliest Western accounts of gunpowder appear in texts written by English philosopher Roger Bacon in the 13th century. he hypothesis that gunpowder was used by ancient Hindus was first mentioned in the eighteenth century by some Sanskrit scholars. The most ardent protagonists were Nathaniel Halhad, Johann Backmann, Quintin Craufurd and Gustav Oppert. However due to lack of sufficient proof, these theories have not been widely accepted.

Gunpowder is assigned the UN number UN0027 and has a hazard class of 1.1D. It has a flash point of approximately 427–464 °C (801–867 °F). The specific flash point may vary based on the specific composition of the gunpowder. Gunpowder's specific gravity is 1.70–1.82 (mercury method) or 1.92–2.08 (pycnometer), and it has a pH of 6.0–8.0.

Gunpowder is classified as a low explosive because of its relatively slow decomposition rate and consequently low brisance. Low explosives deflagrate (i.e., burn) at subsonic speeds, whereas high explosives detonate, producing a supersonic wave. Ignition of the powder packed behind a bullet must generate enough pressure to force it from the muzzle at high speed, but not enough to rupture the gun barrel. Gunpowder thus makes a good propellant, but is less suitable for shattering rock or fortifications. Gunpowder was widely used to fill artillery shells and in mining and civil engineering to blast rock until the second half of the 19th century, when the first high explosives were put into use. Gunpowder is no longer used in modern explosive military warheads, nor is it used as main explosive in mining operations due to its cost relative to that of newer alternatives such as ammonium nitrate/fuel oil (ANFO). Black powder is still used as a delay element in various munitions where its slow-burning properties are valuable.

Gun powder was measured in various ways such as ounces, barrels, pounds and apothecary grains.

Napoleonic war
Weights and turms became more standarised and the kilogram joined the list of mesures.

American Civil War
Nitroglycerin (NG), also known as nitroglycerine, trinitroglycerin (TNG), trinitroglycerine, nitro, glyceryl trinitrate (GTN), or 1,2,3-trinitroxypropane, is a heavy, colorless, oily, explosive liquid most commonly produced by nitrating glycerol with white fuming nitric acid under conditions appropriate to the formation of the nitric acid ester. Chemically, the substance is an organic nitrate compound rather than a nitro compound, yet the traditional name is often retained. Invented in 1847, nitroglycerin has been used as an active ingredient in the manufacture of explosives, mostly dynamite, and as such it is employed in the construction, demolition, and mining industries. Since the 1880s, it has been used by the military as an active ingredient, and a gelatinizer for nitrocellulose, in some solid propellants, such as cordite and ballistite.

Nitroglycerin is also a major component in double-based smokeless gunpowders used by reloaders. Combined with nitrocellulose, there are hundreds of powder combinations used by rifle, pistol, and shotgun reloaders.

For over 130 years, nitroglycerin has been used medically as a potent vasodilator (dilation of the vascular system) to treat heart conditions, such as angina pectoris and chronic heart failure. Though it was previously known that these beneficial effects are due to nitroglycerin being converted to nitric oxide, a potent venodilator, it was not until 2002 that the enzyme for this conversion was discovered to be mitochondrial aldehyde dehydrogenase. Nitroglycerin is available in sublingual tablets, sprays, and patches. Other potential suggested uses include adjunct therapy in prostate cancer.

TNT was first prepared in 1863 by German chemist Julius Wilbrand and originally used as a yellow dye. Its potential as an explosive was not appreciated for several years, mainly because it was so difficult to detonate and because it was less powerful than alternatives. Its explosive properties were first discovered by another German chemist, Carl Haeussermann, in 1891. TNT can be safely poured when liquid into shell cases, and is so insensitive that in 1910, it was exempted from the UK's Explosives Act 1875 and was not considered an explosive for the purposes of manufacture and storage.

The German armed forces adopted it as a filling for artillery shells in 1902. TNT-filled armour-piercing shells would explode after they had penetrated the armour of British capital ships, whereas the British lyddite-filled shells tended to explode upon striking armour, thus expending much of their energy outside the ship. The British started replacing lyddite with TNT in 1907.

Dynamite, nitroglycerin and TNT came up as the latest explosives and made more blast than the gunpowder. Dynamite was a more stable form of nitroglycerin and was cut in to standardised stick lengths in each producing country, thus measurement by sticks and stick lengths and whiths, or if cut by the end users, centimeters and inches of dynamite. Many sticks were made to wieght 1lb or 1kg in wieght or to exsplode with the force of 1lb or kg of compacted (powder rammed hard into a conatiner) gun powder.

WW1
Pure EGDN was first produced by the Belgian chemist Louis Henry (1834–1913) in 1870 by dropping a small amount of ethylene glycol into a mixture of nitric and sulfuric acids cooled to 0 °C. The previous year, August Kekulé had produced EGDN by the nitration of ethylene, but this was actually contaminated with beta-nitroethyl nitrate.

Other investigators preparing NGc before publication in 1926 of Rinkenbach's work included: Champion (1871), Neff (1899) & Wieland & Sakellarios (1920), Dautriche, Hough & Oehme.

The American chemist William Henry Rinkenbach (1894–1965) prepared EGDN by nitrating purified glycol obtained by fractioning the commercial product under pressure of 40mm Hg, and at a temperature of 120°. For this 20g of middle fraction of purified glycol was gradually added to mixture of 70g nitric acid and 130g sulfuric acid, maintaining the temperature at 23°. The resulting 49g of crude product was washed with 300ml of water to obtain 39.6g of purified product. The low yield so obtained could be improved by maintaining a lower temperature and using a different nitrating acid mixture.

1) Direct Nitration of Glycol is carried out in exactly the same manner, with the same apparatus, and with the same mixed acids as nitration of glycerine. In the test nitration of anhydrous glycol (100g) with 625g of mixed acid HNO 3 40% & H 2SO 4 60% at 10-12°, the yield was 222g and it dropped to 218g when the temp was raised to 29-30°. When 500g of mixed acid HNO 3 50% & H 2SO 4 50% was used at 10-12°, the yield increased to 229g. In commercial nitration, the yields obtained from 100 kg anhydrous glycol and 625 kg of mixed acid containing HNO 3 41%, H 2SO 4 58% & water 1% were 222.2 kg of NGc at nitrating temp of 10-12° and only 218.3 kg at 29-30°. This means 90.6% of theory, as compared to 93.6% with NG.

C2H4(OH)2 + 2 HNO3 → C2H4(ONO2)2 + 2 H2O or through the reaction of ethylene oxide and dinitrogen pentoxide:

C2H4O + N2O5 → C2H4(ONO2)2 2) Direct Production of NGc from Gaseous Ethylene. 3) Preparation of NGc from Ethylene Oxide. 4) Preparation of NGc by method of Messing from ethylene through chlorohydrin & ethylene oxide. 5) Preparation of NGc by duPont method.

Explosives were now measured by the ton. The official pound, kilogram and the TNT equivalent was first though up as explosives like Ethylene glycol dinitrate, Hexanite and Amatol came along.

WW2
Torpex is a secondary explosive, 50% more powerful than TNT by mass. Torpex comprises 42% RDX, 40% TNT and 18% powdered aluminium. It was used in the Second World War from late 1942. The name is short for "Torpedo Explosive", having been originally developed for use in torpedoes. Torpex proved to be particularly useful in underwater munitions because the aluminium component had the effect of making the explosive pulse last longer, which increased the destructive power. Torpex was used only in critical applications, e.g. torpedoes and the Upkeep, Tallboy, and Grand Slam bombs. It was also used in the Operation Aphrodite drones. Torpex has long been superseded by H6 and PBX compositions. It is therefore regarded as obsolete, so Torpex is unlikely to be encountered except in old munitions or unexploded ordnance.

Torpex, Composition H6 and Minol were common explosives. Torpex had twist the blast as TNT had, so making a standard table and blast measure necessary when planning a detonation. Every one was already used to TNT, so the bomb's charge would be mesured in lb or kg in dead wieght, but the blast would be measured in the equivalent to the lb or kg TNT expected from such a blast. Example: Torpex is 1/2 more powerfull than TNT, so 1 lb of TNT causes a 1lb blast, but 1 lb of Torpex causes 1.5lb lb bast.

Cold war
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Also see

 * 1) Nukes
 * 2) Torpedoes
 * 3) Popular types of explosives
 * 4) Land and sea mines
 * 5) Ballistic missiles, missiles and military rockets