Publications

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Our previously developed microkinetic model for lean NOx trap (LNT) storage and regeneration has been updated to address some longstanding issues, in particular the formation of N2O during the regeneration phase at low temperatures. To this finalized mechanism has been added a relatively simple (12-step) scheme that accounts semi-quantitatively for the main features observed during sulfation and desulfation experiments, namely (a) the essentially complete trapping of SO2 at normal LNT operating temperatures, (b) the plug-like sulfation of both barium oxide (NOx storage) and cerium oxide (oxygen storage) sites, (c) the degradation of NOx storage behavior arising from sulfation, (d) the evolution of H2S and SO2 during high temperature desulfation (temperature programmed reduction) under H2, and (e) the complete restoration of NOx storage capacity achievable through the chosen desulfation procedure.

Abstract not provided.

The goals of Lustre on Red Sky are: (1) provide home/projects/scratch Lustre file systems; (2) adhere to the Sun HPC stack; (3) implement software RAID on Sun provided JBODs; and (4) design for easy administration. Conclusions are: (1) software RAID includes additional risks and administration vs. hardware RAID solutions; (2) limited testing of hardware in these configurations make it ill-suited for rapid deployment in a production environment; and (3) Lustre has been a shining star on this machine, Red Sky users are pleased with its performance.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

This report outlines a convenient method to calibrate fast (<1ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such a system is used to collect spectral data on plasmas generated in the A-K gap of electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA). On RITS, light is collected through a small diameter (200 micron) optical fiber and recorded on a fast streak camera at the output of 1 meter Czerny-Turner monochromator (F/7 optics). To calibrate such a system, it is necessary to efficiently couple light from a spectral lamp into a 200 micron diameter fiber, split it into its spectral components, with 10 Angstroms or less resolution, and record it on a streak camera with 1ns or less temporal resolution.

Abstract not provided.

Abstract not provided.

This report describes the performance of a high efficiency, compact heater that uses the catalytic oxidation of hydrogen to provide heat to the GM Hydrogen Storage Demonstration System. The heater was designed to transfer up to 30 kW of heat from the catalytic reaction to a circulating heat transfer fluid. The fluid then transfers the heat to one or more of the four hydrogen storage modules that make up the Demonstration System to drive off the chemically bound hydrogen. The heater consists of three main parts: (1) the reactor, (2) the gas heat recuperator, and (3) oil and gas flow distribution manifolds. The reactor and recuperator are integrated, compact, finned-plate heat exchangers to maximize heat transfer efficiency and minimize mass and volume. Detailed, three-dimensional, multi-physics computational models were used to design and optimize the system. At full power the heater was able to catalytically combust a 10% hydrogen/air mixture flowing at over 80 cubic feet per minute and transfer 30 kW of heat to a 30 gallon per minute flow of oil over a temperature range from 100 C to 220 C. The total efficiency of the catalytic heater, defined as the heat transferred to the oil divided by the inlet hydrogen chemical energy, was characterized and methods for improvement were investigated.

Abstract not provided.