{'fraction_non_alphanumeric': 0.02694610778443114, 'fraction_numerical': 0.018962075848303395, 'mean_word_length': 4.569444444444445, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Detonability of Aluminium-Oxygen Suspensions

In a previous work [1], we had predicted the critical conditions for direct initiation of unconfined detonations in aluminium-air and aluminium oxygen suspensions. For aluminium-air the critical initiation energy came out to be Ec = 11 kg of TNT and the critical detonation radius Rc = 8m. These predictions where confirmed by experiments of Zhang et al. [2] in an unconfined (3 m x 3 m cross section and 18 m long) cloud of flaked aluminium particles suspended in air, with a mass concentration of about 290 g/m. When they initiated the mixture with a charge of 8 kg of C4 (which is close to 11kg of TNT), they observed the onset of a detonation after 11 m of propagation. Beyond 15 m to the end of the cloud, a quasi-steady wave propagated with an average velocity of 1460 m/s, that is about 150 m/s smaller than the CJ velocity for the corresponding mixture. With the same model, we had predicted for a stoichiometric aluminium/oxygen suspension, a critical initiation energy for direct detonation initiation to be about Ec = 1 kg of TNT and a critical detonation radius about Rc = 1 m (note that this value corresponds to about 10 J, whereas the minimum detonation initiation energy for most of the hydrocarbon-oxygen mixtures is ranging between 10 J and 1 J) These last predictions were based on the cell size estimated at about 5-10 cm, according to the results of Ingignoli et al. [3]. However, due to the very reduced number of existing data on the detonation cell structure of aluminium-air and aluminium-oxygen suspensions, it comes out that it should be necessary to get a more definitive experimental evidence of these predictions. Hence, we have decided to conceive an experiment in order to investigate the detonability of aluminium-oxygen suspensions. Moreover, as the detonation initiation of an unconfined spherical charge is the more severe test for deciding of the detonability of a mixture, this is the configuration which we have chosen.