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Electropolishing as a Decontamination Process: Progress and Applications.

Description: Electropolishing is a rapid and effective technique for removing plutonium and other radionuclide contamination from a variety of metal surfaces. The major objective of this continuing research is to develop electropolishing into a large-scale decontamination technique that can completely and economically remove transuranic and other surface contamination from large volumes of metallic waste. These research studies have demonstrated the ability of electropolishing to reduce the radiation levels… more
Date: July 28, 1978
Creator: Allen, R. P.; Arrowsmith, H. W.; Charlot, L. A. & Hooper, J. L.
Partner: UNT Libraries Government Documents Department
open access

Characterization of Mo/Si multilayer growth on stepped topographies

Description: Mo/Si multilayer mirrors with nanoscale bilayer thicknesses have been deposited on stepped substrate topographies, using various deposition angles. The multilayer morphology at the stepedge region was studied by cross section transmission electron microscopy. A transition from a continuous- to columnar layer morphology is observed near the step-edge, as a function of the local angle of incidence of the deposition flux. Taking into account the corresponding kinetics and anisotropy in layer growt… more
Date: August 31, 2011
Creator: van den Boogaard, A. J. R.; Louis, E.; Zoethout, E.; Goldberg, K. A. & Bijkerk, F.
Partner: UNT Libraries Government Documents Department
open access

The Thermoelastic Phase Transition in Au-Cd Alloys Studies by Acoustic Emission

Description: The acoustic emission generated during the thermoelastic phase transitions in polycrystalline Au-47.5 at.% Cd and in Au-49 at.% Cd alloys was recorded and analyzed. The emission detected is a manifestation of the frictional energy dissipated by the moving interfaces during the nucleation and growth stages of the reversible phase transitions. It was found that the amount of energy dissipated depends upon the direction of the transformation, the heating or cooling rates, and the specific crystall… more
Date: March 1, 1980
Creator: Baram, I. & Rosen, M.
Partner: UNT Libraries Government Documents Department
open access

Degradation of Thermal Barrier Coatings from Deposits and Its Mitigation

Description: Ceramic thermal barrier coatings (TBCs) used in gas-turbine engines afford higher operating temperatures, resulting in enhanced efficiencies and performance. However, in the case of syngas-fired engines, fly ash particulate impurities that may be present in syngas can melt on the hotter TBC surfaces and form glassy deposits. These deposits can penetrate the TBCs leading to their failure. In experiments using lignite fly ash to simulate these conditions we show that conventional TBCs of composit… more
Date: December 31, 2011
Creator: Padture, Nitin
Partner: UNT Libraries Government Documents Department
open access

Hydrogen Dissociation on Pd4S Surfaces

Description: Exposure of Pd-based hydrogen purification membranes to H,S. a common contaminant in coal gasification streams, can cause membrane performance to deteriorate, either by deactivating surface sites required for dissociative H, adsorption or by forming a low-permeability sulfide scale. In this work. the composition, structure, and catalytic activity of Pd4S, a surface scale commonly observed in Pd-membrane separation of hydrogen from sulfur-containing gas streams, were examined using a combination… more
Date: January 1, 2009
Creator: Miller, J. B.; Alfonso, D. R.; Howard, B. H.; O'Brien, C. P. & Morreale, B. D.
Partner: UNT Libraries Government Documents Department
open access

The Parabolic Growth Op Oxide Solid Solutions on Binary Alloys: A Semi-Empirical Approach.

Description: The growth of solid solution oxide scales on alloys has been described by considering either the transport of the cations themselves, or that of the defect species in the oxide lattice. The two approaches have been shown to be similar. However, it has become apparent that the simplified defect model implicitly assumed in previous analyses using the ionic transport approach is not adequate to fully describe the variation of ionic diffusivities with oxygen potential or oxide composition. Further … more
Date: October 1, 1980
Creator: Whittle, D. P.; Gesmundo, F. & Viani, F.
Partner: UNT Libraries Government Documents Department
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