1 / 8

Explosions

Explosions. Explosions. Explosives: substances that undergo a rapid oxidation reaction with the production of large quantities of gases. A sudden buildup of gas pressure determines the nature of the explosion.

lenore
Download Presentation

Explosions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Explosions

  2. Explosions Explosives: substances that undergo a rapid oxidation reaction with the production of large quantities of gases. • A sudden buildup of gas pressure determines the nature of the explosion. • The speed at which explosives decompose permits their classification as high or low explosives. ARSON AND EXPLOSION

  3. Low uses Black or Smokeless powder: • Black powder is a mixture of potassium or sodium nitrate, charcoal, and sulfur. • Smokeless powder consists of nitrated cotton (nitrocellulose) or nitroglycerin and nitrocellulose.

  4. High Explosions Primary and Secondary: • Primary explosives are ultrasensitive to heat, shock, or friction and provide the major ingredients found in blasting caps or primers used to detonate other explosives. • Secondary explosives are relatively insensitive to heat, shock, or friction and will normally burn rather than detonate if ignited in small quantities in the open air. • This group comprises the majority of commercial and military blasting, such as dynamite, TNT, PETN, and RDX. ARSON AND EXPLOSION

  5. The Explosive Market • In recent years, nitroglycerin-based dynamite has all but disappeared from the industrial explosive market and has been replaced by ammonium nitrate-based explosives (i.e., water gels, emulsions, and ANFO explosives). • In many countries outside the United States, the accessibility of military high explosives to terrorist organizations makes them very common constituents of homemade bombs. • RDX is the most popular and powerful of the military explosives, often encountered in the form of pliable plastic known as C-4. ARSON AND EXPLOSION

  6. Collection and Analysis Items collected: • Loose soil from the crater for analysis for chemicals • Foreign items not belonging to the scene • Trace of detonating mechanism • Objects can be screened in the field by the ion mobility spectrometer (IMS). ARSON AND EXPLOSION

  7. Collection and Analysis Collection and Storage: • All materials collected must be placed in sealed air-tight containers. • Debris and articles collected from different areas are to be packaged in separate air-tight containers. • Some explosives can diffuse through plastic and contaminate nearby containers so containers should be glass. ARSON AND EXPLOSION

  8. Back at the Lab • Debris collected at explosion scenes will be examined with a microscope. • Recovered debris may also be thoroughly rinsed with organic solvents and analyzed by • color spot tests • thin-layer chromatography • high-performance liquid chromatography • gas chromatography-mass spectrometry. • Confirmatory identification tests may be performed on unexploded materials by either infrared spectrophotometry or X-ray diffraction. ARSON AND EXPLOSION

More Related