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Shock Waves and Detonations, Explosive Performance
Published in Per-Anders Persson, Roger Holmberg, Jaimin Lee, Rock Blasting and Explosives Engineering, 2018
Per-Anders Persson, Roger Holmberg, Jaimin Lee
Mathematically, oxygen balance is given as the ratio between the mass of oxygen which must be added to or removed from the composition to achieve oxygen balance and the mass of the composition. It is positive for oxygen-rich explosives and is expressed as a fraction or percentage of the explosive formula mass, for example grams O2/100 grams explosive. For an explosive which contains only some or all of the atoms: aluminum, boron, carbon, calcium, chlorine, fluorine, hydrogen, potassium, nitrogen, sodium, and oxygen (with the formula AlalBbCcCacaClclFfHhKkNnNanaOo), the oxygen balance will be () oxygen balance=−32(34al+34b+1c+12ca−14cl−14f+14h+14k+0n+14na−12o)explosive molecular weight×100%.
Explosives
Published in Michael L. Madigan, First Responders Handbook, 2017
Oxygen balance is an expression that is used to indicate the degree to which an explosive can be oxidized. If an explosive molecule contains just enough oxygen to convert its entire carbon to carbon dioxide, all of its hydrogen to water, and all of its metal to metal oxide with no excess, the molecule is said to have a zero oxygen balance. The molecule is said to have a positive oxygen balance if it contains more oxygen than is needed, and a negative oxygen balance if it contains less oxygen than is needed.
Safety-Hazard Impact Metrics
Published in John Andraos, Synthesis Green Metrics, 2018
This definition applies to compounds that have the potential of being oxidizing agents would be involved in hypothetical complete reduction reactions where oxygen is liberated. Hence, nsubstrate>nproducts, and (OB)j>0. This indicates a positive oxygen balance, since a net liberation of oxygen occurs.
Laser Ignition of Two Low-Vulnerability RDX-Based Gun Propellants: Influence of the Atmosphere on Ignition and Combustion Properties
Published in Combustion Science and Technology, 2023
S. Delbarre, L. Courty, M. William-Louis, P. Gillard
Ignition and combustion properties of two insensitive RDX-based gun propellants were experimentally investigated. Results especially focused on the influence of atmosphere on ignition delays, energies giving 50% of probability of ignition, maximum overpressures, and maximum propagation rates. Initial pressure and laser power were also studied as driving parameters. Combustion under synthetic air has given very different results depending on the propellant. For P1, air turned out to provide the best combustion properties, overcoming the negative oxygen balance of RDX and HTPB, compared with argon and nitrogen. On the contrary, combustion of P2 under air and argon appeared to be very similar: the low effect of atmosphere on the decomposition products of NC and the high molar heat capacity of air seem to balance its chemical advantage compared with argon. This experimental study is part of a wider project which aims to model ignition and combustion processes of low-vulnerability gun propellants using detailed kinetics chemistry. The results presented here will thus enable the comparison with overpressures or burning rates provided by the future model.
Peculiarity for the stability of three different emulsion explosives
Published in Journal of Dispersion Science and Technology, 2022
Kai-ming Zhang, Zhen-zhen Cui, Xing-yu Chen, Hai-rong Zhao
Emulsion explosive is usually manufactured in two steps. Firstly, ammonium nitrate (AN) supersaturated solution and oil materials are emulsified into emulsion explosive matrix. The matrix is a water-in-oil (W/O) highly concentrated emulsion because the content of AN supersaturated solution is much higher than that of oil materials follow the basic principle of zero oxygen balance of industrial explosive formulation design, and its internal phase is dispersed in the external phase in a micron-level size.[9,10] Secondly, the matrix is made into emulsion explosive by mixing with hollow glass spheres (microspheres) or air bubbles.[11,12] Like most emulsions, the emulsion explosive is a thermodynamic unstable system, and its W/O microstructure will be continuously destroyed with time.[13,14] Therefore, the stability is an extremely crucial symbol for emulsion explosive because it not only determines whether explosive can be used normally, but also has a very important impact on the safety in its manufacture, storage, transport and usage, for example, in the blasting construction operation, treating the residual drugs which failed to completely explode has an obvious danger, if the stability drops, the risk of incomplete explosion of explosive will significantly increase.
Study of Combustion Characteristics of Magnesium/Sodium Nitrate Pyrotechnics Under Sub-Atmospheric Pressure
Published in Combustion Science and Technology, 2022
Zefeng Guo, Jian Ju, Hua Guan, Chengkuan Shi, Zejun Li
The zero oxygen balance magnesium/sodium nitrate/phenolic resin (36.8%/60.2%/3%) pyrotechnic combination was created to investigate the effect of low pressure environment on pyrotechnic combustion performance. The synchronous thermal analyzer Netzsch sta449f3 (USA) was used to investigate the pyrotechnic’s low pressure reaction mechanism. The pyrotechnic charge was produced into grains of the same size at the same time, and the low-pressure combustion test was performed in a vacuum box. The luminous intensity, flame spectrum and infrared radiation performance of the flame were recorded by sgx-100 transient light intensity instrument, ocean optics USB 4000 spectrophotometer and FLIR t1050sc infrared thermal imager respectively. The findings serve as a benchmark for pyrotechnic applications in low-pressure environments.