Shock induced vaporization of anhydrite CaSO4 and calcite CaCO3

Discovery of abundant anhydrite (CaSO4) and gypsum (CaSO4.2H2O) in the otherwise carbonate sediments comprising the upper portion of the rocks contained within the Chicxulub impact crater has prompted research on the shock-induced vaporization of these minerals. We use a vaporization criterion determined by shock-induced entropy. We reanalyze the shock wave experiments of Yang [1]. He shocked 30% porous anhydrite and 46% porous calcite. Post-shock adiabatic expansion of the sample across a 5 mm-thick gap and then impact upon an aluminum witness plate backed by LiF window that is monitored with a VISAR. Reanalysis uses Herrman's P-alpha model [2] for porous materials, and a realistic interpolation gas equation-of-state for vaporization products. Derived values of the entropies for incipient and complete vaporization for anhydrite are 1.65±0.12 and 3.17±0.12 kJ(kg.K)–1, and for calcite these are 0.99±0.11 and 1.93±0.11 kJ(kg.K)–1. Corresponding pressures for incipient and complete vaporization along the Hugoniot of non-porous anhydrite are 32.5±2.5 and 122±13 GPa and for non-porous calcite are 17.8±2.9 and 54.1±5.3 GPa, respectively. These pressures are a factor of 2–3 lower than reported earlier by Yang

A Situation of Economic Management in NTU Cooperative Fuzzy Games

In economic management, we often use some (divisible) private resources to cooperative. Fuzzy coalitions always be used to describe this situation in cooperative fuzzy games. In this paper, we proposed two new solution concepts in NTU cooperative fuzzy games, and discussed their properties

Oblique impact jetting of geological materials

To understand jetting of earth materials, gabbro slabs (5 mm thick) were accelerated to 1.5–2 km/s and impacted inclined gabbro (5–10 mm thick), novaculite (10 mm thick) and porous sandstone (12 mm thick) targets at angles of 30°–60°. The ejecta were collected using a catcher box filled with styrofoam and the particles were extracted using chloroform. The mass of the ejected particles per unit area (∼50 mg/cm^2) remains almost independent of impact velocity, inclination angle, thickness of the target and sample mineralogy and density. Based on this result, we predict that a 500 m diameter asteroid will produce only ∼10^7 gm tektite material. This is negligible comparing to an estimated 2×10^(13) gm in the Ivory Coast tektite strewn field. The recovered ejecta, unlike most tektites, contains both target and impactor materials. Both of the above results suggest that the tektites are not produced by jetting