NASA Scientific and Technical Aerospace Reports

X-ray photoelectron spectroscopy, in combination with argon ion milling and target factor analysis, was applied to provide an
independent estimate of the rate constant that agreed with the gravimetric result.
NTIS
Corrosion; Stainless Steels; Austenitic Stainless Steels
20040068245 Lockheed Martin Corp., Syracuse, NY, USA
Thermal-Hydraulics and Electrochemistry of a Boiling Solution in a Porous Sludge Pile. A Test Methodology
Voelker, R. F.; May 2001; 16 pp.; In English
Report No.(s): DE2004-821678; LM-01K030; No Copyright; Avail: Department of Energy Information Bridge
When boiling occurs in a pile of porous corrosion products (sludge), chemical species can concentrate. These species can
react with the corrosion products and transform the sludge into a rock hard mass and/or create a corrosive environment. In-situ
measurements are required to improve the understanding of this process, and the thermal-hydraulic and electrochemical
environment in the pile. A test method is described that utilizes a water heated instrumented tube array in an autoclave to
perform the in-situ measurements. As a proof of method feasibility, tests were performed in an alkaline phosphate solution.
The test data is discussed.
NTIS
Electrochemistry; Hydraulics; Sludge
20040068284 Lawrence Livermore National Lab., Livermore, CA
Effect of Welding on the Breakdown and Repasivation Potentials of Alloy 22 in 5 M CaC1(2)
Ilevbare, G. O.; Aug. 28, 2003; In English
Report No.(s): DE2003-15004667; UCRL-JC-155209; No Copyright; Avail: National Technical Information Service (NTIS)
The study of the electrochemical behavior of wrought and welded Alloy 22 was carried out in 5 M CaCl2 between 45
and 120 degrees Centigrade with Multiple Crevice Assembly (MCA) specimens. The susceptibility to corrosion was found to
increase with increase in temperature in both the wrought and the welded forms of the alloy. The weld metal was found to
be less susceptible to localized corrosion under the conditions tested. Alloy 22 (UNS number N06022) is a nickel alloy rich
in chromium and molybdenum, with a high degree of corrosion resistance. It exhibits a low general corrosion rate under most
conditions and has formidable localized corrosion resistance in most environments compared with other nickel alloys. Alloy
22 is the candidate material for the fabrication of high-level nuclear waste containers. These containers are intended for use
for disposal of high-level radioactive waste and spent nuclear fuel.
NTIS
Welding; Nickel Alloys; Electrochemistry; Wrought Alloys
20040068287 Rutherford Appleton Lab., Oxford, UK
Computational Complexity of CCSD(T) Algorithms in Electron Correlation Studies for Atoms and Molecules
Wilson, S.; Sep. 2003; 38 pp.; In English
Report No.(s): PB2004-105657; Copyright; Avail: National Technical Information Service (NTIS)
The CCSD(T) method, a coupled cluster approach including all single and double excitations together with an a posteriori
perturbative correction for connected triple excitations, is believed to provide an optimum balance between accuracy and
efficiency in electron correlation studies. In this report, we analyze the computational complexity of CCSD(T) algorithms.
After considering a prototypical fourth order triple excitation energy diagram in the many-body perturbation theory (MBPT)
expansion for a closed-shell system, we consider the tensor contraction which arises in the evaluation of the corresponding
energy component and also the use of spin-adaption and the efficiencies which follow in the computational algorithm from
its effective exploitation. The CCSD(T) approximation is presented in a compact form and the algebraic complexity of
algorithms for this approximation considered in detail. Reduced-complexity algorithms for CCSD(T) calculations are
considered. In particular, we consider low-order scaling techniques for extended molecular systems, Laplace transform
techniques, and Cholesky decomposition techniques.
NTIS
Clusters; Algorithms; Computation
20040068296 Rutherford Appleton Lab., Oxford, UK
Critical Analysis of the ‘CCSD(T)’ Model for the Study of Electron Correlation Effects in Atoms and Molecules
Wilson, S.; Sep. 2003; 46 pp.; In English
Report No.(s): PB2004-105656; Copyright; Avail: National Technical Information Service (NTIS)
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