Mechanical contact explosions

The mechanism of explosion of molten salt at 1100°C in accidental contact with water was studied. 

A mixture of the alcohol with formic acid rapidly self-heated, then reacted violently [1], A stirred mixture with cyanoacetic acid exploded violently after application of heat [2], Contact with acids causes self-condensation of the alcohol, which may be explosively violent under unsuitable physical conditions. The general mechanism has been discussed [3], The explosion hazards associated with the use of acidic catalysts to polymerise furfuryl alcohol may be avoided by using as catalyst the condensation product of 1,3-phenylenediamine and l-chloro-2,3-epoxypropane [4], See Nitric acid Alcohols (reference 6)... 

Sodium ignites in fluorine gas but is inert in the liquefied gas [1]. Cold sodium ignites in moist chlorine [2] but may be distilled unchanged in the dry gas [1]. Sodium and liquid bromine appear to be unreactive on prolonged contact [3], but mixtures may be detonated violently by mechanical shock [4]. Finely divided sodium luminesces in bromine vapour [1], Iodine bromide or iodine chloride react slowly with sodium, but mixtures will explode under a hammer-blow [1]. Interaction of iodine pentafluoride with solid sodium is initially vigorous, but soon slows with film-formation, while that with molten sodium is explosively violent... 

Previous literature on formation of various types of copper acetylides is discussed and the mechanism of their formation is examined, with experimental detail. Whenever a copper or copper-rich alloy is likely to come into contact with atmospheres containing [1] ammonia, water vapour and acetylene, or [2] lime-sludge, water vapour and acetylene, or a combination of these two, there is the probability of acetylide formation and danger of explosion. The action is aided by the presence... 

Contact with metal oxides increases the sensitivity of nitromethane, nitroethane and 1-nitropropane to heat (and of nitromethane to detonation). Twenty-four oxides were examined in a simple quantitative test, and a mechanism was proposed. Cobalt, nickel, chromium, lead and silver oxides were the most effective in lowering ignition temperatures [1]. At 39 bar initial pressure, the catalytic decomposition by chromium or iron oxides becomes explosive at above 245° C [2],... 

These results stimulated a number of studies, both in industry (Conoco, Esso, Shell Pipeline) and in academia (University of Maryland, M.I.T.). The objective was, primarily, to delineate the mechanism that led to these explosive events. The results of many small-scale experiments, primarily conducted by Shell Pipeline Corporation and M.I.T., led to the hypothesis that the apparent explosion was, in fact, a very rapid vaporization of superheated LNG. Contact of LNG, of an appropriate composition, with water led to the heating of a thin film of the LNG well above its expected boiling temperature. If the temperature reached a value where homogeneous nucleation was possible, then prompt, essentially explosive vaporization resulted. This sequence of events has been termed a rapid phase transition (RPT), although in the earlier literature it was often described by the less appropriate title of vapor explosion. 

Whereas these early experiments provided interesting data, no mechanism was developed to explain the explosion phenomenon. In fact, since the 1950s there has been little interest in conducting further studies in dissolver tanks because the addition of efficient steam-shatter jets at the smelt entrance has effectively eliminated explosions in this section of the process. Further studies were directed to the explosions which took place within the recovery boiler as a result of water contacting the smelt on the furnace floor. 

Explosive Actuator, Linear. A self-contained power transmitting device designed to convert chemical energy into controlled mechanical force in the form of linear mechanical movement. It is comprised essentially of a piston, propellant chge, electrical bridge wire and contacts enclosed in a housing (Ref 38b, pp 3-4, Actuator, Explosive, Linear)... 

JM Mine was moored, pear-shaped, contact mine which had no horns. The jolt received by the pendulum firing mechanism, when a ship struck the mine, closed an electrical contact and fired the detonator. - The mine was filled with ca 110 lbs of a HE ( ) (pp 44-45, Fig 18) Pomegranate Mine was a Vickers antenna mine purchased before WWII. It was spherical, 41 inches in diam, with six chemical horns on the upper hemisphere and two addnl ones welded to the lower hemisphere. An upper antenna and float and/or lower antenna were secured to the mine. No data for HE filler (pp 44 45, Fig 19) Type 3 Mine was the first Japanese attempt to use influence mines, copied from German S Mine. Their cylindrical A1 cases were either 7 or 11 feet long and 21 inches in diam. No data for HE used and the description of the mine given in Ref 1, p 46 is hard to understand Mark 2 Mod 1 Explosive Hook was actually a device for mine sweeping rather than a mine. 

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