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Comparison of the Acceptability of Various Oil Shale Processes (open access)

Comparison of the Acceptability of Various Oil Shale Processes

While oil shale has the potential to provide a substantial fraction of our nation's liquid fuels for many decades, cost and environmental acceptability are significant issues to be addressed. Lawrence Livermore National Laboratory (LLNL) examined a variety of oil shale processes between the mid 1960s and the mid 1990s, starting with retorting of rubble chimneys created from nuclear explosions [1] and ending with in-situ retorting of deep, large volumes of oil shale [2]. In between, it examined modified-in-situ combustion retorting of rubble blocks created by conventional mining and blasting [3,4], in-situ retorting by radio-frequency energy [5], aboveground combustion retorting [6], and aboveground processing by hot-solids recycle (HRS) [7,8]. This paper reviews various types of processes in both generic and specific forms and outlines some of the tradeoffs for large-scale development activities. Particular attention is given to hot-recycled-solids processes that maximize yield and minimize oil shale residence time during processing and true in-situ processes that generate oil over several years that is more similar to natural petroleum.
Date: March 11, 2006
Creator: Burnham, A K & McConaghy, J R
System: The UNT Digital Library
IN SITU INVESTIGATION OF THE PASSIVATION OF ALLOY C22 AND OF THE PASSIVE FILMS FORMED ON ALLOY C22 IN ACIDIC ELECTROLYTES AT ROOM TEMPERATURE AND AT 90 DEGREES C (open access)

IN SITU INVESTIGATION OF THE PASSIVATION OF ALLOY C22 AND OF THE PASSIVE FILMS FORMED ON ALLOY C22 IN ACIDIC ELECTROLYTES AT ROOM TEMPERATURE AND AT 90 DEGREES C

The passive films formed on Alloy C22 in several acidic solutions were investigated by a combination of five in situ techniques: cyclic polarization, electrochemical impedance spectroscopy, Mott-Schottky analyses, electrochemical quartz crystal microbalance measurements, and surface enhanced Raman spectroscopy. Similar tests were conducted on unalloyed samples of nickel, chromium and molybdenum, which are the main alloying elements of Alloy C22. The results of the tests conducted on nickel, chromium, and molybdenum helped to determine the roles of these elements in the passivation of Alloy C22. In general, the corrosion resistance of C22 was superior to that of unalloyed chromium. Although chromium is an important component of the passive film on Alloy C22, the other elements figure prominently in the corrosion resistance of C22 in acidic solutions. The passivity of Alloy C22 was detrimentally affected by increasing concentrations of hydrogen ions, chloride ions, and increasing temperature. The results of this study provide understanding of the resistance/susceptibility of Alloy C22 to corrosion by the aggressive solutions that can develop inside pits and crevices.
Date: March 11, 2006
Creator: M. Miyagusuku, S. Harrington, and T. M. Devine
System: The UNT Digital Library
ON THE TEMPERATURE-DEPENDENCE OF QUARKONIA CORRELATORS. (open access)

ON THE TEMPERATURE-DEPENDENCE OF QUARKONIA CORRELATORS.

Here I review the temperature-dependence of heavy quarkonia correlators in potential models with three different screened potentials, and compare these to the results from lattice QCD. None of the potentials investigated yield results consistent with the lattice data, indicating that screening is likely not the mechanism for heavy quarkonia suppression. I also discuss a simple toy model, not based on temperature-dependent screening, that can reproduce the lattice results.
Date: March 11, 2006
Creator: MOCSY, A.
System: The UNT Digital Library