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Abstract  

DSC measurements have been used to investigate the thermal stability of each of four specific detection agents, prescribed by the International Civil Aviation Organization for incorporation into explosives at the point of manufacture. Additionally, the compatibility of these agents with a number of commercial explosives has been assessed. DSC results for a complete study of mixtures of the agents with the explosive, tetryl are specifically described. The thermograms are compared with those of the pure agents and tetryl, the thermal decomposition of which has been previously characterized.

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Abstract  

The thermal properties of 2,3-dimethyl-2,3-dinitrobutane (DMNB), a detection agent for explosives, have been determined by DSC measurements. Additionally, the results of an NMR study are compared with conclusions arrived at in the literature with regard to the source of two endotherms observed in the DSC. The thermal decomposition of DMNB is characterized by an exotherm with an energy in excess of 3 kJ g−1, observed in conjunction with a third endotherm resulting from the fusion of DMNB. Arrhenius parameters determined from both variable heating rate and isothermal measurements in the DSC are compared with predicted values assuming various mechanisms for the decomposition process.

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Abstract  

The thermal decomposition of explosives: pentaerythrol tetranitrate (PETN), 2,4,6-trinitrotoluene(TNT), cyclo-1,3,5-trimethylene-2,4,6-trinitroamine (RDX) and their two-component mixtures with 40% of lead compounds [PbO, Pb3O4, Pb(NO3)2] were performed. The simple method of determination of stability changes in the mixtures described above, in comparison with pure explosives was presented. The lead oxides accelerated significantly the thermal decomposition of explosives. Pb(NO3)2 acts as a catalyst in the mixture containing TNT degradation, but not in a case of PETN and RDX.

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Summary Manufactures of commercially available explosives guarantee a certain lifetime of their products. In the commercial field this lifetime is usually large enough. The explosive is normally used long before the end of its lifetime. It may happen that these explosives are stored for a long time in a bunker where they sometimes exceed their lifetime. A large set of commercial explosives is characterized with a TG by heating small samples in aluminium sample cups from room temperature to 550°C, under a nitrogen atmosphere, with three different heating rates (2, 5 and 10 K min-1). The activation energy of the decomposition step is determined in several different ways. After this characterization, a selection of the samples (based on economical value) is artificially aged for periods of 2, 4 and 6 weeks. After these ageing profiles the samples are re-investigated with the TG under the same conditions (heating rates and atmosphere) followed by the calculation of the kinetic parameters of the artificially aged materials. According to the TG measurements almost all tested explosives appear to have a much longer lifetime than the values given by the manufacturer. From kinetic point of view, the different methods for calculating the activation energy result in approximately the same parameters. It may conclude that TG seems to be a reliable and quick method for the determination of the lifetime of commercial explosives.

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Abstract  

The thermal decomposition of an explosive material is accompanied by generation of a certain amount of heat and, under certain conditions, can lead to the well-known phenomena of self-ignition. Therefore, it is of great importance to predict whether or not an explosive material will ignite under given conditions (specimen mass and shape, surrounding temperature, etc.). An own computer program named THERMEX, for studying thermal ignition phenomena, is discussed in this paper. The program uses the finite difference method to describe the reactive heat conduction phenomena in infinite slab, cylindrical, and spherical geometry of explosive materials. The analysis of the stability requirements of the finite difference method applied in the program is carried out. The program is tested by the comparison of calculated results with the results of calculation by other authors. Reasonable agreement was found under identical computational conditions.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: Ye Zongyuan, Li Yubing, Ding Shengyao, Bao Zongyu, Yang Xiaoyun, and Rong Chaofan

Abstract  

Bombs concealed in luggage have threatened human life and property throughout the world's traffic. The plastic explosives could not be checked by the X-ray detecting device. A method has been tested in the present work for non-destructive detection of explosives. A neutron generator and relevant apparatus have been used as a tool to find explosives, regardless of the bomb's shape and the packing materials. It seems that this method is a promising one because of the strong transmission ability of both the incident and output specific radiations and low background.

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, Separation of Conformers of Nitramines by High-Performance Liquid Chromatography, Propellants, Explosives, Pyrotechnics (2000) (submitted for publication). R. Krishnamurthy, S. M. Baker , and B. M

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The explosive sensitivity of methylammonium perchlorates has been investigated by differential thermal analysis, thermogravimetric analysis, mass spectrometry and explosion delay experiments. The decomposition temperature of these compounds increases in the order CH3NH3ClO4>(CH3)2NH2ClO4>(CH3)3NHClO4. The activation energy shows the reverse order, indicating thereby that the stability increases with increasing substitution. Mass spectrometric investigation, however, suggests an increasing reactivity with increasing substitution. A possible explanation for such behaviour is proposed. It appears that explosion delay is correlated with thermal decomposition and impact sensitivity.

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Journal of Thermal Analysis and Calorimetry
Authors: Jianjun Li, Xuguang Wang, Rongzu Hu, Bin Kang, Yuxiang Ou, and Boren Chen

Abstract  

The determination of the most probable mechanism function and the calculation of kinetic parameters of thermal decomposition of powder emulsion explosives have been achieved by different kinetic equations and different kinetic methods from data non-isothermal SC-DSC curves, DSC curves, and thermal explosion delay curve. The courses which the reaction would follow under adiabatic conditions are predicted.

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Abstract  

Materials which release significant heat upon decomposition are energetic materials. Some of these are also explosives. Seeking a correlation with detonability of large quantities of energetic materials, four laboratory tests were used. The characteristics considered indicative of detonability were ability to fragment a metal casing, when initiated by a detonator, and ability to produce large quantities of gas and heat. The best developed of these tests is differential scanning calorimetry. It has already been pioneered by other researchers. A limitation of this study is that large-scale detonability remains unknown for a number of materials examined; thus, it is difficult to sufficiently evaluate the success of the small-scale analyses.

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