Wednesday, March 4, 2015





Detonation

Detonation (from Latin detonare, meaning "to expend thunder") is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations occur in both conventional solid and liquid explosives, as well as in reactive gases. The velocity of detonation in solid and liquid explosives is much higher than that in gaseous ones, which allows the wave system to be observed with greater detail (higher resolution).

An extraordinary variety of fuels may occur as gases, droplet fogs, or dust suspensions. Oxidants include halogens, ozone, hydrogen peroxide and oxides of nitrogen. Gaseous detonations are often associated with a mixture of fuel and oxidant in a composition somewhat below conventional flammability ratios. They happen most often in confined systems, but they sometimes occur in large vapor clouds. Other materials, such as acetylene, ozone and hydrogen peroxide




Explosive material

An explosive material, also called an explosive, is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An explosive charge is a measured quantity of explosive material.

This potential energy stored in an explosive material may be

  • chemical energy, such as nitroglycerin or grain dust
  • pressurized gas, such as a gas cylinder or aerosol can.
  • nuclear energy, such as in the fissile isotopes uranium-235 and plutonium-239

Explosive materials may be categorized by the speed at which they expand. Materials that detonate (the front of the chemical reaction moves faster through the material than the speed of sound) are said to be "high explosives" and materials that deflagrate are said to be "low explosives". Explosives may also be categorized by their sensitivity. Sensitive materia

Explosive weapon

An explosive weapon generally uses high explosive to project blast and/or fragmentation from a point of detonation.

Explosive weapons may be subdivided by their method of manufacture into explosive ordnance and improvised explosive devices (IEDs). Certain types of explosive ordnance and many improvised explosive devices are sometimes referred to under the generic term bomb.

When explosive weapons fail to function as designed they are often left as unexploded ordnance (UXO).

In the common practice of states, explosive weapons are generally the preserve of the military, for use in situations of armed conflict, and are rarely used for purposes of domestic policing. Certain types of explosive weapons may be categorised as light weapons (e.g. hand-held under-barrel and mounted grenade launchers, portable launchers of anti-tank missile and rocket systems; portable launchers of anti-aircraft missile systems (MANPADS); and mortars of calibres of less than 100 mm

Pyroelectric fusion

Pyroelectric fusion refers to the technique of using pyroelectric crystals to generate high strength electrostatic fields to accelerate deuterium ions (tritium might also be used someday) into a metal hydride target also containing deuterium (or tritium) with sufficient kinetic energy to cause these ions to undergo nuclear fusion. It was reported in April 2005 by a team at UCLA. The scientists used a pyroelectric crystal heated from âˆ'34 to 7 °C (âˆ'29 to 45 °F), combined with a tungsten needle to produce an electric field of about 25 gigavolts per meter to ionize and accelerate deuterium nuclei into an erbium deuteride target. Though the energy of the deuterium ions generated by the crystal has not been directly measured, the authors used 100 keV (a temperature of about 109 K) as an estimate in their modeling. At these energy levels, two deuterium nuclei can fuse together to produce a helium-3 nucleus, a 2.45 MeV neutron and bremsstrahlung. Although it make

Polywell

The polywell is a type of nuclear fusion reactor that uses an electric field to heat ions to fusion conditions. It is closely related to the magnetic mirror, the fusor, the biconic cusp and the high beta fusion reactor. A set of electromagnets generates a magnetic field which traps electrons. This creates a negative voltage, which attracts positive ions. As the ions accelerate towards the negative center, their kinetic energy rises. If the ions collide in the center, they can fuse.

The polywell is one of many devices that use an electric field to heat ions to fusion conditions. This branch of fusion research is known as inertial electrostatic confinement. The polywell was developed by Robert Bussard, as an improvement over the fusor. His company, EMC2, Inc., developed the initial devices for the U.S. Navy.

Mechanism


<img title="Polywell" alt="Polywell" style="width:400px;display:block;margin-left: auto;margin-right: