NASA Scientific and Technical Aerospace Reports

in the design and production of the Spallation Neutron Source room temperature linac if this process were utilized.
NTIS
Accelerators; Computer Aided Design; Computer Aided Manufacturing; Linear Accelerators
20040111144 Lockheed Martin Corp., Syracuse, NY, USA
Zinc Treatment Effects on Corrosion Behavior of 304 Stainless Steel in High Temperature, Hydrogenated Water
Ziemniak, S. E.; Hanson, M.; Mar. 2001; 42 pp.; In English
Report No.(s): DE2004-821695; LM-01K133; No Copyright; Avail: Department of Energy Information Bridge
The purpose of this work is to quantify the effects of trace levels of zinc additions to a mildly alkaline, hydrogenated water
on 304 stainless steel by: (1) lowering the corrosion rate and (2) modifying the corrosion oxide layer.
NTIS
Stainless Steels; Zinc Alloys
20040111145 Princeton Univ., NJ
Particle-in-cell Simulations with Kinetic Electrons
Lewandowski, J. L. V.; Feb. 2004; 34 pp.; In English
Report No.(s): DE2004-821523; PPPL-3923; No Copyright; Avail: Department of Energy Information Bridge
A new scheme, based on an exact separation between adiabatic and nonadiabatic electron responses, for particle-in-cell
(PIC) simulations of drift-type modes is presented. The (linear and nonlinear) elliptic equations for the scalar fields are solved
using a multigrid solver. The new scheme yields linear growth rates in excellent agreement with theory and it is shown to
conserve energy well into the nonlinear regime. It is also demonstrated that simulations with few electrons are reliable and
accurate, suggesting that large-scale, PIC simulations with electron dynamics in toroidal geometry (e.g. tokamaks and
stellarators plasmas) are within reach of present-day massively-parallel supercomputers.
NTIS
Multigrid Methods; Kinetic Equations; Tokamak Devices
20040111154 Lockheed Martin Corp., Syracuse, NY, USA
Defect Structure and Evolution in Silicon Carbide Irradiated to 1 dpa-SiC at 1100 deg C
Senor, D. J.; Youngblood, G. E.; Greenwood, L. R.; Archer, D. V.; Alexander, D. L.; May 2002; 44 pp.; In English
Report No.(s): DE2004-821701; LM-02K037; No Copyright; Avail: Department of Energy Information Bridge
Transmission electron microscopy (TEM), swelling measurements, isochronal annealing, and thermal diffusivity testing
were used to characterize the effects of radiation damage in SiC. Together, these techniques provided a comprehensive set of
tools for observing and characterizing the structure and evolution of radiation-induced defects in SiC as a function of
irradiation temperature and dose. In this study, two types of dense, crystalline, monolithic SiC were subjected to irradiation
doses up to 1 dpa-SiC at a temperature of 1100 C, as well as post-irradiation annealing up to 1500 C. The microscopic defect
structures observed by TEM were correlated to changes in the macroscopic dimensions, thermal diffusivity and thermal
conductivity. The results demonstrated the value of using ultrapure(beta)SiC as an effective reference material to characterize
the nature of expected radiation damage in other, more complex, SiC-based materials such as SiC/SiC composites.
NTIS
Transmission Electron Microscopy; Annealing; Thermal Diffusivity
20040111155 National Inst. of Standards and Technology, Gaithersburg, MD, USA, Sandia National Labs., Albuquerque,
NM
Stopwatch and Timer Calibrations
Gust, J. C.; Graham, R. M.; Lombardi, M. A.; May 2004; 68 pp.; In English
Report No.(s): PB2004-107229; NIST/SP-960-12; No Copyright; Avail: CASI; A04, Hardcopy
This document is a recommended practice guide for stopwatch and timer calibrations. It discusses the types of
stopwatches and timers that require calibration, the specifications and tolerances of these devices, and the methods used to
calibrate them. It also discusses measurement uncertainties and the process of establishing measurement traceability back to
national and international standards. This guide is intended as a reference for the metrologist or calibration technician. It
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