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A classical method for understanding the coupling between northern and southern hemispheres during millennial-scale climate events is based on the correlation between Greenland and Antarctic ice core records of atmospheric composition. Here we present a ne ...
Two studies of the effect of changing CH4 fluxes on global tropospheric oxidant levels, O3, OH, H2O2, have been performed with a multi-box photochemical model. 1) A sensitivity study is made by scaling back CH4, CO and NO emissions relative to present-day ...
The deuterium excess of polar ice cores documents past changes in evaporation conditions and moisture origin. New data obtained from the European Project for Ice Coring in Antarctica Dome C East Antarctic ice core provide new insights on the sequence of ev ...
Proceedings of the National Academy of Sciences2005
The atmospheric methane concentration in ancient times can be reconstructed by analysing air entrapped in bubbles of polar ice sheets. We present results from an ice core from Central Greenland (Eurocore) covering the last 1000 years. We observe variations ...
We study by means of ab initio calculations the ideal tensile and shear strengths of the C-46 clathrate phase. While its bulk modulus and elastic constants are smaller than in diamond, its strength is found to be in all directions larger than the critical ...
X-ray diffraction (XRD) is a powerful technique for the study of crystalline materials. The technique of Rietveld refinement now enables the amounts of different phases in anhydrous cementitious materials to be determined to a good degree of precision. Thi ...
The state-resolved reactivity of CH4 in its totally symmetric C-H stretch vibration (nu(1)) has been measured on a Ni(100) surface. Methane molecules were accelerated to kinetic energies of 49 and 63.5 kJ/mol in a molecular beam and vibrationally excited t ...
We summarize (1) knowledge about the global pre-industrial cycle of CO2 and CH4, and (2) recent reconstructions of the concentration of CO2 and CH4 in the atmosphere (CO2atm and CH4atm) based on ice cores drilled in Antarctica and Greenland. We discuss cri ...
This paper is part of the special publication Gas hydrates: relevance to world margin stability and climatic change (eds J.P. Henriet and J. Mienert). The Antarctic and Greenland ice contains an almost direct record of past atmospheric CH 4. The record ove ...
Dense planar and tubular oxygen separation membranes of La 0.6Ca0.4Fe0.75Co0.25O3-d were investigated as reactors for the partial oxidation (POX) of methane to syngas. Disk-shaped membranes were prepared by compaction and tubes by extrusion. Their permeati ...
