Multiple chondritic meteorite fragments have been found in two sedimentary rock samples from an end-Permian bed at Graphite Peak in Antarctica. The Ni/Fe, Co/Ni, and P/Fe ratios in metal grains; the Fe/Mg and Mn/Fe ratios in olivine and pyroxene; and the chemistry of Fe-, Ni-, P-, and S-bearing oxide in the meteorite fragments are typical of CM-type chondritic meteorites. In one sample, the met...

This paper presents the calculation of the diffraction of axisymmetric borehole waves by bed boundary discontinuities. The bed boundary is assumed to be horizontal and the inhomogeneities to be axially symmetric. In such a geometry, an axially symmetric source will produce only axially symmetric waves. Since the borehole is an open structure, the mode spectrum consists of a discrete part as wel...

Transport of suspended sediment in high Reynolds number channel flows Re=O 600 000 is simulated using large-eddy simulation along with a dynamic-mixed model DMM . Because the modeled sediment concentration is low and the bulk Stokes’ number Stb is small during the simulation, the sediment concentration is calculated through the use of the Eulerian approach. In order to employ the DMM for the su...

A reacting packed-bed undergoing a high-temperature thermochemical solid-gas transformation is considered. The steamand dry-gasification of carbonaceous materials to syngas is selected as the model reaction. The exact 3D digital geometrical representation of the packed-bed is obtained by computer tomography and used in direct pore-level simulations to characterize its morphological and radiativ...

a r t i c l e i n f o Ripples and transverse dunes in areas of abundant sand supply increase in height and spacing as a function of time, grain size, and excess shear velocity. How and why each of these factors influence ripple and transverse dune size, however, is not precisely known. In this paper, the controls on the height and spacing of ripples and transverse dunes in areas of abundant san...