Cu foils, 200 µm in thickness, were heated in two stages by a ∼100-ns-long mono-energetic electron bunch at 19.8 MeV and a current of 1.7 kA (8.5×10 14 e-) in a 2-mm-spot to Te ∼ 1 eV. After 45 ns of isochoric heating the pressure in the foil builds upto >20 GPa (200 kbar), it begins to hydrodynamically disassemble, and a velocity spread is measured. Near the end of the electron pulse the 1550 nm probe is cutoff or absorbed. Photonic doppler velocimetry measurements were made to quantify the expansion velocity, hydrodynamic disassembly time, and pressure of the foil prior to cutoff. Measurements indicate foil motion begins the instant electrons pass through the foil and continues until the particle velocity approaches the ambient sound velocity of Cu and the bulk density exceeds the critical density of the probe. Once the density of the plasma drops below the critical threshold and begins reflecting again, an expansion velocity of the classical plasma is also measured, similar to the point-source solution.

The inside cover picture shows the expansion of a copper cylinder containing hydrazinium nitrate based explosives, with and without deuterium substitution. Using high‐fidelity detonation velocity and wall expansion velocity measurements, the kinetic isotope effect was utilized to probe reactions between Al and detonation product gases. By varying explosives with either H or D and including Al, data indicate that Al oxidation occurs on an extremely fast time scale, with post‐detonation kinetic isotope effects observed in carbon containing formulations. Details are discussed in the article by Bryce C. Tappan et al. on page 62 ff.

The high-temperature, high-pressure, entrained-flow, laboratory-scale gasifier at the Colorado School of Mines, including the primary systems and the supporting subsystems, is presented. The gasifier is capable of operating at temperatures and pressures up to 1650 °C and 40 bar. The heated section of the reactor column has an inner diameter of 50 mm and is 1 m long. Solid organic feedstock (e.g., coal, biomass, and solid waste) is ground into batches with particle sizes ranging from 25 to 90 μm and is delivered to the reactor at feed rates of 2-20 g/min. The maximum useful power output of the syngas is 10 kW, with a nominal power output of 1.2 kW. The initial characterization and demonstration results of the gasifier system with a coal feedstock are also reported.

During or shortly after a detonation in condensed explosives, the reaction rates and the physical mechanism controlling aluminum reaction is poorly understood. We utilize the kinetic isotope effect to probe Al reactions in detonation product gases in aluminized, protonated and deuterated high explosives using high-fidelity detonation velocity and cylinder wall expansion velocity measurements. By observation of the profile of cylinder wall velocity versus time, we are able to determine the timing of aluminum contribution to energy release in product gases and observe the presence or absence of rate changes isotopic substitution. By comparison of the Al oxidation with lithium fluoride (LiF), data indicate that Al oxidation occurs on an extremely fast time scale, with post-detonation kinetic isotope effects observed in carbon containing formulations.

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