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Hexanitrostilbene (HNS) is an energetic ingredient that is widely used in commercial and military explosives for its thermal stability. However, characterization of its thermodynamic parameters and phase stability is lacking. Crystalline properties, such as bulk modulus and thermal expansion, are necessary to accurately predict the behavior of shocked solids using hydrodynamic codes. In order to obtain these values, equations of state of fine-particle (type IV) HNS were investigated using synchrotron angle-dispersive x-ray diffraction experiments at static high-pressure and temperature. The samples were compressed and heated using diamond anvil cells. Pressure - volume data for HNS at ambient temperature were fit to the Birch-Murnaghan and Vinet formalisms to obtain bulk modulus and its first pressure derivative. Temperature - volume data at ambient pressure were fit to obtain the volume thermal expansion coefficient. [ABSTRACT FROM AUTHOR]

The detonation and subsequent combustion of aluminized explosive formulations depend heavily on the oxidation reactions of aluminum. Fuel-rich formulations require oxygen from an external source (nominally an oxygen-containing atmosphere or detonation products) to burn the fuel to completion. Dynamic spectroscopic measurements are made for an aluminized explosive (PBXIH-135) to investigate the effect of changing atmospheres on the combustion properties of aluminum. The explosive formulation is tested under normal atmospheric conditions and in an atmosphere of nitrogen. Light emission (from 350–550 nm) from the explosive event is collected in a spectrometer and dispersed temporally in a streak camera. Aluminum emission (centered at 396 nm) is commonly observed in each atmosphere although the emission persists longer in nitrogen. Aluminum nitride (AlN) is observed as an intermediate in the oxidation of aluminum when oxygen is removed from the atmosphere. New, nitrogen-containing species (near 387 and 418 nm) also arise in the nitrogen atmosphere experiments. A slower, less intense aluminum monoxide (AlO) emission observed in the nitrogen atmosphere may correspond to the slower oxidation reactions of aluminum and detonation products (CO2 and H2O). The peak assignments and global kinetics of each species are presented and the implications of these results on atmospheric effects are discussed. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]