Study Guide
#20
Analysis of Explosives
Introduction
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Most bombing incidents involve homemade explosive devices
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There are a great many types of explosives and explosive
devices
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Lab must determine type of explosives and, if possible, reconstruct
the explosive device
Chemistry
of Explosion
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Essentially a combustion reaction - like a fire
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Major difference is speed of reaction
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Damage caused by rapidly escaping gases and confinement
Types
of Explosives
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Low explosives
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Escaping gases up to about 3000fps
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Crucial element is physical mixture of oxygen and fuel
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Examples are black and smokeless powders
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Black powder is mixture of potassium nitrate, charcoal and
sulfur
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Smokeless powder is nitrocellulose and perhaps nitroglycerine
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High explosives
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Velocity of escaping gases up to 10,000fps
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Oxygen usually contained infuel molecule
Two types
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Initiating - Senistive, will detonate readily when subjected
to heat or shock. Used to detonate other explosives in explosive train
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Noninitiating - relatively insensitive, requires heat or
shock. Includes TNT or PETN
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Ammonium nitrate based
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Water gels
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Emulsions
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ANFO’s
Analysis
of Explosives
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Microscopy
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Thin layer chromatography
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Visualise with Greiss reagents
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Infrared spectrophotometry
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X-ray diffraction
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Detonator fragments
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