Issue 10 Volume 41 May 16, 2003

generated in the winding during the fast temperature rise can result in a permanent damage of the brittle Nb(3)Sn. Although
there are several studies of the critical current degradation of Nb(3)Sn strands due to strain, little is known about how to apply
the strain limitations to define a maximum acceptable temperature in the coils during a quench. Therefore, an experimental
program was launched, aimed at improving the understanding of the effect of thermo-mechanical stress in coils made from
brittle Nb(3)Sn. A first experiment, reported here, was performed on cables. The experimental results were compared to
analytical and finite element models. The next step in our experimental program will be to repeat similar measurements in
small racetrack coils and later in full size magnets.
NTIS
High Field Magnets; Mathematical Models; Particle Accelerators; Thermodynamics; Superconductors (Materials); Niobium;
Tin; Stress Distribution
20030037125 National Inst. of Standards and Technology (MSEL), Gaithersburg, MD
Determination of Texture from Individual Grain Orientation Measurements
Blendell, J. E.; Vaudin, M. D.; Fuller, E. R.; 2002; 14 pp.
Report No.(s): PB2003-102700; No Copyright; Avail: CASI; A03, Hardcopy
We present a technique for determining the texture of a polycrystalline material based on the measurement of the
orientation of a number of individual grains. We assumed that the sample has fiber (i.e. axisymmetric) texture and that the
texture can be characterized by a function (the March-Dollase function) with a single parameter. We simulated a large number,
N, of orientation data sets, using the March-Dollase function for a total of five different texture parameters, r(init) Using the
maximum likelihood method we solved for the texture parameter, r(prime) that best fits each simulated data set in order to
determine the distribution of r(prime) evaluate the precision and accuracy with which r(prime) can be determined. The 90\%
confidence limits of the ratio r(prime)/rinit varied as N-1/2 but were independent of r(init). Using the texture of slightly
textured alumina as determined by x-ray diffraction we calculated the 90\% confidence limits for measurements of 131 grains.
The orientations of 131 grains in textured alumina were measured by electron backscatter diffraction and the texture
determined from those measurements lay within these 90\% confidence limits.
NTIS
X Ray Diffraction; Maximum Likelihood Estimates; Aluminum Oxides; Electron Diffraction; Polycrystals
20030037134 National Inst. of Standards and Technology (MSEL), Gaithersburg, MD, American Superconductor Corp.,
Westborough, MA, Los Alamos National Lab., NM
Method for Crystallographic Texture Investigations Using Standard X-Ray Equipment
Vaudin, M. D.; Rupich, M. W.; Jowett, M.; Riley, G. N.; Bingert, J. F.; 2002; In English
Report No.(s): PB2003-102698; No Copyright; Avail: National Technical Information Service (NTIS)
A fast and accurate method has been developed for measuring crystalline texture in homogeneous materials. The method
uses a conventional powder x-ray diffractometer capable of q scans. Two scans are recorded from the sample: first, a high
resolution q-2q scan is obtained of a Bragg peak whose diffracting planes are normal to the preferred orientation direction;
second, a q scan is obtained using this peak. The q scan contains the required texture information but the intensities must be
corrected for defocussing and absorption to obtain the texture profile. The q-2q scan of the Bragg peak is used to make the
defocussing correction, and first principles calculations are used to correct for absorption. The theory behind these corrections
is presented here. The validity of the technique has been verified by making measurements on untextured alumina. Data
obtained from Bi2Sr2Ca2Cu3O10 superconducting tape specimens with this technique are compared with texture data
obtained with a four-circle diffractometer.
NTIS
Crystallography; Textures; X Ray Diffraction; Superconductivity; Homogeneity
77
PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
Includes quantum mechanics; theoretical physics; and statistical mechanics. For related information see also 72 Atomic and Molecular
Physics, 73 Nuclear Physics, and 25 Inorganic, Organic and Physical Chemistry.
20030033033 Air Force Research Lab., Edwards AFB, CA, USA
Heat Transfer and Deposition Behavior of Hydrocarbon Rocket Fuels
Bates, Ron; June 18, 2002; 3 pp.; In English
Contract(s)/Grant(s): AF Proj. 4847
Report No.(s): AD-A410534; AFRL/PRS-ED-AB-2002-148; No Copyright; Avail: CASI; A01, Hardcopy
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