Impact and ignition

S or P (no example of compn is given in CA) were sensitive to impact and ignition, their heat of expln and energy were high, but bri-sance and deton rate low]... 

Uranium Dicarbide. UC2 mw 262.05 metallic crysts mp 2350—2400° bp 4370° d 11.28g/cc at 16°. Decompd by dil inorg acids, and v violently by w. Prepn is by heating a mixt of U oxide and sugar charcoal at 1370° in a C crucible by means of an electric furnace for 5 to 10 minutes. The compd emits brilliant sparks on impact, and ignites on grinding in a mortar or on heating in air to 400°. In particle sizes of less than 40 microns, it is spontaneously flammable. The dicarbide reacts with incandescence with halogens or N2 above 300°... 

Another type of bomb used to a considerable extent during WWII was the multiple effect bomb. It contained either magnesium or phosphorus in separate units. These units were ejected from the bomb upon impact and ignition and scattered over a wide area. The burning Mg units could be handled in the same manner as the electron bomb. The P units could be treated with water, but should be removed to a safe place before allowing them to... 

Johansson and co-workers (7, 8, 9) have shown that heat transfer from a compressed spherical bubble does not increase the temperature of its liquid surface sufficiently to account for the impact sensitivity of liquid explosives the high sensitivity of nitroglycerin is postulated as arising from the fact that small droplets are readily formed by the impact and ignited by the compressed air. Bolkhovitinov (1) postulated crystallization of the liquid under the impact pressure, with the phase transition causing the temperature increase which causes explosions. Bowden (3) favors the adiabatic compression of gas bubbles combined with the dispersion of the explosive into fine particles as the mechanism for initiation by mechanical impact. 

If an expl is intended for use in primers, then its brisance and power may be lower than for groups (1), (2) and (3), but it should possess low sensitivity to impact and friction and should produce a hot flame in order to ignite a charge of proplnt or a deiay train... 

Chlorates and perchlorates react violently with metals when they are exposed to heat (the salt is then in molten state), a flame, a spark, friction or impact. The ignition often involves very spectacular blinding flames. The mixtures can detonate the conditions of the reaction depend on how the interaction is... 

Itforms impact-sensitive mixtures with ethers (dioxane, etc.) and halocarbons (carbon tetrachloride) and ignites in oxygen at 100°C [1,2]. An improved and safer synthesis of decaborane from pentaborane is given [3],... 

The peroxyester is stable in storage at —25°C, and samples did not explode on friction, impact or heating. However, a 10 g sample stored at ambient temperature heated spontaneously, exploded and ignited [1], A sample stored at -30°C exploded during manipulation at 0-5°C [2],... 

Mixtures with phosphorus explode on impact, and that with sulfur ignites on frictional initiation. 

Mixtures of potassium and solid carbon dioxide are shock-sensitive and explode violently on impact, and carbon monoxide readily reacts to form explosive carbonylpotassium (potassium benzenehexoxide) [1]. Dichlorine oxide explodes on contact with potassium [2], Potassium ignites in dinitrogen tetraoxide or dinitrogen pentaoxide at ambient temperature and incandesces when warmed with nitrogen oxide or phosphorus(V) oxide [3], At — 50°C, potassium and carbon monoxide react to give dicarbonylpotassium, which explodes in contact with air or water, or at 100°C. At 150°C, the product is a trimer of this, potassium benzenehexoxide. The just-molten metal ignites in sulfur dioxide [4],... 

Alloys containing 10-70% of zirconium will pulverise and ignite on impact. 

Clear, colorless to yellow, oily fuming liquid with a pungent, musty odor that is disagreeable and lingering. This material is hazardous through inhalation and ingestion, and produces local skin/eye impacts. May ignite combustible materials. 

Qualitative studies26 have shown that (1) the ignition probability increases as the size of the vapor cloud increases, (2) vapor cloud fires are more common than explosions, (3) the explosion efficiency is usually small (approximately 2% of the combustion energy is converted into a blast wave), and (4) turbulent mixing of vapor and air and ignition of the cloud at a point remote from the release increases the impact of the explosion.27... 

While solid fires generally do not have the same impact as flammable material fires in process units, the hazards from solids are important in several respects. Class A materials may be the source of ignition for hazards having a greater combustible loading or posing a greater threat in terms of impact and Class A or D solids may pose a threat due to inherent reactivity or use in a process. For more information on solid fires, refer to SFPE Handbook (Beyer, 2002). Radiant heat from solid fires can be calculated similarly to that of pool fires. 

Both 2,4-dinitrosoresorcinol (23) and 2,4-dinitroresorcinol (24) are important in the explosives industry. The lead salt of 2,4-dinitrosoresorcinol has a low ignition temperature and finds use in priming compositions and in electrical igniters. The lead salt of 2,4-dinitroresorcinol is a weak initiator but is found to exhibit high sensitivity to friction and stab action without being highly sensitive to impact, and as such, this compound has found use in primers. 

Treatment of the isomeric l,3a,4,6a- (220) and 1,3a,6,6a- (91) dibenzotetraazapentalenes with mixed acid or fuming nitric acid forms z-TACOT (225) and y-TACOT (231), respectively. 438 z xaCOT (225) and y-TACOT (231) are highly insensitive to impact and electrostatic charge and exhibit extremely high thermal stability (ignition temperature 494 °C, DTA curve 354 °C). 

The British developed several intensive type bombs, such as the one filled with gasoline and ignited on impact by a Very cartridge but none was as successful as the small unit bombs developed by them later... 

This represents the ease with which an explosive can be set off by a blow friction and is expressed in terms of what occurs when a pendulum of known weight scrapes across an explosive (ignites or explodes or snaps or crackles). Sensitivity to friction is less well-defined than the sensitivity to impact and is expressed only by figures compared with a standard. Some explosives can be arranged as follows in terms of decreasing sensitivity. 

The performance of the illuminating formulations is assessed by various parameters such as burning rate, luminosity and luminous efficiency. In addition to performance, some other important characteristics such as sensitivity to impact and friction, ignition temperature, mechanical properties and luminosity are also... 

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