Fringe Mixtures

The trend seen with TATP has been recently mirrored with other highly dangerous mixtures. As commercial explosives become more difficult to procure, by both legitimate and illicit means, terrorist groups determined to conduct bombing operations are forced to work with more dangerous and unpredictable formulations. A prime example of this can be seen in the major bombings carried out in Indonesia over the last two and a half years. 

As discussed in the history section, chlorates have been long utilized by terrorist groups for small bombing attacks. Sodium chlorate is a very common weed killer throughout many European countries. The mixture of sodium chlorate and nitrobenzene (CO-OP) by PIRA was discussed earlier. Most commonly, chlorate is mixed with sugar to make an explosive filler for pipe bombs. 

As mentioned earlier, chlorates are also a major ingredient in various pyrotechnic formulations. Typically potassium chlorate is utilized in this capacity due to the more hygroscopic nature of the sodium analog. Mixed with powdered aluminum and/or sulfur, potassium chlorate produces a mixture commonly referred 

Interviews of suspects associated with the Bali bombings indicated that the bomb makers produced approximately 1000 kg of a chlorate flash powder incorporating both aluminum powder and sulfur. This device was delivered via vehicle to the targeted nightclub. Precursor chemicals were easily purchased in Indonesia due to the geographical proximity to China, which remains one of the largest producers of pyrotechnics in the world. 

It should be noted that the use of chlorate has not been limited to Bali. Two more attacks using chlorate-based improvised explosives occurred in Indonesia followed the Bali bombing. On August 5, 2003, the J.W. Marriott hotel was bombed in Jakarta. In an even bolder attack the Australian Embassy in Jakarta was bombed on September 9, 2004. This continued reliance on a highly sensitive main charge in Indonesia illustrates that terrorists will utilize whatever tools are at their disposal regardless of the risks. 

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Figure 7. The TEM micrograph of a relatively short WS2 nanotube obtained in a strong reducing atmosphere (5% H2 95% N2 gas mixture). Each two fringes (WS2 layers) are separated by 0.62 nm (8c).

The shape of moving boundary of crystals was different if the composition of melt mixture was changed. When pure benzene was compressed, the shape of moving boundcu y of crystal was roundish. The fringe shape made 1 90.0 mole percent benzene was slightly sharp, and the crystals formed from the melt 80.0 and 70.0 mole percent benzene had sharper moving boundary. But the details of these difference are not clear and future studies are expected. 

It is now generally accepted that the morphology of a polymer depends on the contributions of three different macro-conformations (a) the random coil or irregularly folded molecule as found in the glassy state, (b) the folded chain, as found in lamellar structures and (c) the extended chain. The fringed micelle (d) may be seen as mixture of (a), (b) and (c) (see Fig. 2.12) with paracrystallinity as an extreme. 

FIG. 2.12 Schematic drawing of the different macro-conformations possible in solid linear macromolecules, (a) Random, glassy (b) folded chain, lamellar (c) extended chain equilibrium (d) fringed micelle, mixture of (a) to (c) (after Wunderlich, 1970). 

Figure 4.27 Traiumission electron micrographs of a mixture of a star diblock copolymer (polybutadiene-polystyrene) with a homopolymer (polystyrene). The upper EM images show mesh layers viewed end-on. The lower image shows the mesh sheets viewed from above, revealing the dense network of pores in the layers, so that the sheets are in fact a filigree of interconnected tunnels. The large-scale dark (one marked A) and bright (B) fringes are due to variations in the thickness of the specimen only. Pictures reproduced witti permission from [48].

The above brief review illustrates that chemical derivatization techniques have been used extensively for the confirmation of identity of organochlorine residues. In most instances, the lower limits of detectability of the derivatives are substantiaUy lower than the established tolerance values for the parent compounds. Taken in conjunction with the many other modes of derivatization—e.g., during or after gas chromatography (59)— the analyst has a vast array of modification procedures at hand to aid in residue identification. They can be employed for residues in soil, biological, fat, and nonfat extracts and can be successfuUy extended, especially the more specific tests, to the identification of crosscontaminants in pesticide formulations and also fertilizer mixtures. So far, these latter two cases have only been a fringe area of application (60,61). 

Fig. 4.1.15. First and second order reflexion spectra of a cholesteric liquid crystal film (0.45 0.55 mole fraction mixture of 4 -bis(2-methylbutoxy)-azoxybenzene and 4,4 -di-n-hexoxyazoxybenzene) 15 pitch lengths or 11.47 on thick. Angle of incidence 45°. Polarizer and analyser are parallel to the plane of reflexion for and normal to it for measurements. The small oscillations are interference fringes from the two cholesteric-glass interfaces. (After Berreman and Scheffer. )...

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