JA2 and M30 recovered from interrupted ETC-closed bomb, interrupted ETC small-scale chamber, and open-air experiments were subjected to chemical and microscopic analysis. Evidence of subsurface reaction in both M30 and JA2 has been discovered using a desorption-gas chromatography-mass spectroscopy (D-GC-MS) method to detect low levels of NO in the propellant. It appears that for M30, profiles for radiation-induced denitration of nitrate esters are consistent with Beer's law, and that effects occur as deep as 0.5 mm into the exposed surface. Radiation-induced denitration in JA2 has been detected as deep as 0.75 mm from the exposed surface, but profiles are not consistent with Beer's law. It is suspected that denitration at and below the exposed JA2 surface occurs mostly in locations where large graphite particles are found. Rough estimates of graphite particle temperature when exposed to plasma radiation are in excess of those required for denitration to occur. Microscopic examination of plasmaexposed propellant indicates several features (pits, gouges, blisters, wormholes, etc.) that increase the surface area of the propellant and can contribute to an increased burning rate.u

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The time-varying gradient fields generated during Magnetic Resonance Imaging (MRI) procedures have the potential to induce electrical current on implanted endocardial leads. Whether this current can result in undesired cardiac stimulation is unknown. This paper presents an optically coupled system with the potential to quantitatively measure the currents induced by the gradient fields into endocardial leads during MRI procedures. Our system is based on a microcontroller that works as analog-to-digital (A/D) converter and sends the current signal acquired from the lead to an optical high-speed light-emitting-diode transmitter. Plastic fiber guides the light outside the MRI chamber, to a photodiode receiver and then to an acquisition board connected to a PC. The preliminary characterization of the performances of the system is also presented.