A single-culture bioprocess of Methanothermobacter thermautotrophicus to upgrade digester biogas by CO2 -to-CH4 conversion with H2.

We optimized and tested a postbioprocessing step with a single-culture archaeon to upgrade biogas (i.e., increase methane content) from anaerobic digesters via conversion of CO(2) into CH(4) by feeding H(2) gas.

Radion-induced brane preheating.

When the interbrane separation in the compact Randall-Sundrum model is stabilized using the Goldberger-Wise mechanism, a potential is generated for the four-dimensional field, the radion, that encodes this separation. Coherent oscillations of the radion in the early universe will produce an exponential growth in the number of brane particles due to parametric amplification. We describe the conditions necessary for this process, which resembles the preheating phase in inflation, and show the exponential growth in the case of a scalar field confined to a brane.