Explosives

Incendiary weapons, incendiary devices, incendiary munitions, or incendiary bombs are weapons designed to start fires. They may destroy structures or sensitive equipment using fire, and sometimes operate as anti-personnel weaponry. Incendiaries utilize materials such as napalm, thermite, magnesium powder, chlorine trifluoride, or white phosphorus. Though colloquially often called "bombs", they are not explosives but in fact operate to slow the process of chemical reactions and use ignition rather than detonation to start or maintain the reaction. Napalm, for example, is petroleum especially thickened with certain chemicals into a gel to slow, but not stop, combustion, releasing energy over a longer time than an explosive device. In the case of napalm, the gel adheres to surfaces and resists suppression.

Drilling and blasting is the controlled use of explosives and other methods, such as gas pressure blasting pyrotechnics, to break rock for excavation. It is practiced most often in mining, quarrying and civil engineering such as dam, tunnel or road construction. The result of rock blasting is often known as a rock cut.

Drilling and blasting currently utilizes many different varieties of explosives with different compositions and performance properties. Higher velocity explosives are used for relatively hard rock in order to shatter and break the rock, while low velocity explosives are used in soft rocks to generate more gas pressure and a greater heaving effect. For instance, an early 20th-century blasting manual compared the effects of black powder to that of a wedge, and dynamite to that of a hammer. The most commonly used explosives in mining today are ANFO based blends due to lower cost than dynamite.

An explosive belt (also called suicide belt, suicide vest or bomb vest) is an improvised explosive device, a belt or a vest packed with explosives and armed with a detonator, worn by suicide bombers. Explosive belts are usually packed with ball bearings, nails, screws, bolts, and other objects that serve as shrapnel to maximize the number of casualties in the explosion.

The Turnip Winter (German: Steckrübenwinter, pronounced [ˈʃtɛkʁyːbn̩ˌvɪntɐ]) of 1916 to 1917 was a period of profound civilian hardship in Germany during World War I, named for the resulting use of turnips as a famine food.

The Turnip Winter occurred during the winter of 1916–1917. Continually poor weather conditions led to a diminished harvest, most notably in cereal production. An ongoing blockade by the Allies of World War I had also reduced Germany's food imports. The food shortages were also attributed to a seizure of horses for the Imperial German Army, the conscription of a large part of the agricultural workforce, and a shortage of farming fertilizers caused by the diversion of nitrogen to the production of explosives. In response to the food shortage, the German government introduced food rationing through the then-new War Food Office. In the summer of 1917, the food allocated offered only 1,560 calories (6,500 kJ) daily diet and dropped to 1,000 calories per day in winter. The Imperial Health Office (renamed "Reich Health Office" in 1918) required 3,000 calories (12,600 kJ) for a healthy adult male, three times what was available in winter. German soldiers relied for their survival on the availability of turnips. Driven by starvation, children started breaking into barns and looting orchards in search of food. Such disregard for authority effectively doubled the youth crime rate in Germany. Historian G.J. Meyer noted that, according to a report from a prominent Berlin physician, "eighty thousand children had died of starvation in 1916". Worker strikes were also common during this time as food shortages often directly led to labor unrest.

A Hesco bastion,also known as a Hesco barrier, and formally Concertainer, is a gabion introduced in 1989 and primarily used for flood control and military fortifications. It is made of a collapsible wire mesh container and heavy-duty geotextile fabric liner and is used as a temporary to semi-permanent levee or blast wall against small-arms fire or explosives. It has been used in military applications in Iraq and Afghanistan.

The exploding-bridgewire detonator (EBW, also known as exploding wire detonator) is a type of detonator used to initiate the detonation reaction in explosive materials, similar to a blasting cap because it is fired using an electric current. EBWs use a different physical mechanism than blasting caps, using more electricity delivered much more rapidly. They explode with more precise timing after the electric current is applied by the process of exploding wire. The precise timing of exploding wire detonators compared with other types of detonators has led to their common use in nuclear weapons.

The slapper detonator is a more recent development along similar lines.

In thermodynamics, the Helmholtz free energy (or Helmholtz energy) is a thermodynamic potential that measures the useful work obtainable from a closed thermodynamic system at a constant temperature (isothermal). The change in the Helmholtz energy during a process is equal to the maximum amount of work that the system can perform in a thermodynamic process in which temperature is held constant. At constant temperature, the Helmholtz free energy is minimized at equilibrium.

In contrast, the Gibbs free energy or free enthalpy is most commonly used as a measure of thermodynamic potential (especially in chemistry) when it is convenient for applications that occur at constant pressure. For example, in explosives research Helmholtz free energy is often used, since explosive reactions by their nature induce pressure changes. It is also frequently used to define fundamental equations of state of pure substances.

The Royal Arsenal, Woolwich is an establishment on the south bank of the River Thames in Woolwich in south-east London, England, that was used for the manufacture of armaments and ammunition, proofing, and explosives research for the British armed forces. It was originally known as the Woolwich Warren, having begun on land previously used as a domestic warren in the grounds of a mid-16th century Tudor house, Tower Place. Much of the initial history of the site is linked with that of the Office of Ordnance, which purchased the Warren in the late 17th century in order to expand an earlier base at Gun Wharf in Woolwich Dockyard.

Over the next two centuries, as operations grew and innovations were pursued, the site expanded massively. At the time of the First World War the Arsenal covered 1,285 acres (520 ha) and employed close to 80,000 people. Thereafter its operations were scaled down. It finally closed as a factory in 1967 and the Ministry of Defence moved out in 1994. Today the area, so long a secret enclave, is open to the public and is being redeveloped for housing and community use.

Sodium nitrate is the chemical compound with the formula NaNO₃. This alkali metal nitrate salt is also known as Chile saltpeter (large deposits of which were historically mined in Chile) to distinguish it from ordinary saltpeter, potassium nitrate. The mineral form is also known as nitratine, nitratite or soda niter.

Sodium nitrate is a white deliquescent solid very soluble in water. It is a readily available source of the nitrate anion (NO₃), which is useful in several reactions carried out on industrial scales for the production of fertilizers, pyrotechnics, smoke bombs and other explosives, glass and pottery enamels, food preservatives (esp. meats), and solid rocket propellant. It has been mined extensively for these purposes.