Explosibility screening

I placed a weighed quantity of sodium borohydride in a flask and attached it to a dropping funnel which contained water. The outlet from the flask was connected to a gas meter. The entire assembly was placed behind an explosion screen, since I did not know how violent the reaction might be. 

Materials that in the past were never considered to pose a viable threat have been successfully utilized in numerous attacks. If explosive screening technology hopes to match the growing threats, it will have to expand into the realm of reactive chemicals, which were previously discounted as nonviable for illicit use. 

Although reliable and capable of operation by non-specialists with trace detection capabilities useful for explosives screening, IMS analyzers are comparatively low in resolution although specificity of response is strong owing to the method of ionization of sample and the additional evaluation of product ions with mobility, increased specificity and expanded scope of response to an enlarged list of explosives is a reasonable... 

Cook, D.J., Decker, B.K, Maislin, G., and Allen, M.G. (2004) Through container THz sensing applications for explosive screening. Proa IEEE Int Conf. Terahertz Electron., 6, 34—37. 

A low incidence of explosions has been reported when precipitation is effected without a nucleating agent and during the screening process. Precautions must be taken during detonator loading to prevent dusting and to maintain a scmpulously clean operation. 

The incorporation of aluminum increases the blast effect of explosives but decreases the rates of detonation, fragmentation effectiveness, and shaped charge performance. Mixes with aluminum are made by first screening finely divided aluminum, adding it to a melted RDX—TNT slurry, and stirring until the mix is uniform. A desensitizer and calcium chloride may be incorporated, and the mixture cooled to ca 85°C then poured. Typical TNT-based aluminized explosives are the tritonals (TNT + Al), ammonals (TNT, AN, Al), minols (TNT, AN, Al) torpexes and HBXs (TNT, RDX, Al) (Table 14) (223-226). 

Theatrical Pyrotechnics or Special Effects. Many spectacular visual and audible effects are produced for stage presentations of both music and drama, and many motion pictures and television shows incorporate pyrotechnic and explosive special effects to Hven up the presentation. These spectacular effects are a combination of pyrotechnics, explosives, combustion, and electronics. After the effects are filmed or videotaped, they are often enhanced by slow-motion replay and by the addition of more exciting noise. A real explosion is over in milliseconds, and hence there is a need for electronic enhancement to create a more spectacular effect on the screen. 

Through-ckculation compartments employ perforated or screen bottom trays and suitable flow baffles so gas is forced through the material. If material is not inherently pervious to gas flow, it may be mechanically shaped iato noodles, pellets, or briquettes. These dryers are used ia small-scale operations to dry explosives, foods, and pigments. Dryer efficiency is 50—70%. Based on tray area, water vaporization rates are 1—10 kg/(h-m ). 

H. Ozonizalion of organic compounds. The ozonization of each unsaturated organic compound is more or less an individual problem, but some general comments may be made. Organic ozonides are highly explosive, and hence it is safest to carry out the ozonization in a solvent which dissolves both the original compound and the ozonide. In all cases, a shatterproof screen of laminated safety glass should be placed between the operator and the tubes H, I, and J. A second screen should be placed back of the tubes to protect other pieces of the apparatus. 

To prevent glass fragments from flying in the event of an explosion, use should be made of metal gauzes to screen reaction flasks etc., or cages, e.g. for desiccators. Vessels of awkward size/shape may be covered with cling film. 

The following case study illustrates the use of SCREEN. In this example we analyze a fire incident that occurred at a wood preserving facility. The incident involved a fire and explosion of six cylindrical vessels containing creosote and pentachlorophenol. Refer to Figure 15. 

The recent rise in the use of expolosives in terrorist activity poses new challenges to industry and law enforcement. This challenge is being met by the use of sophisticated chemical detection devices to screen for bombs and more rigorous explosive inventory safeguards and controls. Plans have also been proposed to tag explosives with isotopes to make them easier to trace if misused. 

Benchmark 2 continues the emphasis on persistence, bioaccumulation, and toxicity, but at lower threshold values. In addition. Benchmark 2 includes flammability and explosiveness. It is anticipated that many chemicals will not move past Benchmark 2 because of the broad scope of hazards and challenging threshold values included in the Green Screen. 

Explosihility screening. In the literature an extensive collection of explosion properties of chemical compounds can be found. However, if literature is unavailable or properties have not been examined yet, a number of initial screening techniques exist. If the checks for explosibility of the starting materials, intermediates, or products reveal a great hazard from deflagration or detonation, it is advisable to abandon the process. 

The difference between this test and the previous one is that layers of screens are added between the substance and the explosive in order to measure tiie shockwave effect of the detonator on the substance. 

A detonator, in the form of explosive plates made with tetryl then a screen made of cellulose acetate plates is placed in a wooden container. A 26 mm diameter cylinder full of the substance to be analysed is placed on the screen, and finally a steel plate on top of the cylinder is added. If the substance transmits the detonation, the steel plate will be pierced and not projected. Piercing serves as an indicator of detonation transmission. The number of cellulose acetate disks needed between the sample and the detonator to prevent the detonation from being transmitted is found. Only one is needed for most chemical substances, but with m-dinitrobenzene, 240 are required. 

Initial screening (Section 3.2) —Through identification of materials and conditions present at the specific site Material Safety Data Sheets Process conditions Total inventory of materials being handled Information on site conditions as needed to evaluate explosion or fire potential... 

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