A statistical analysis and computational algorithm for comparing pairs of tool marks via profilometry data is described. Empirical validation of the method is established through experiments based on tool marks made at selected fixed angles from 50 sequentially manufactured screwdriver tips. Results obtained from three different comparison scenarios are presented and are in agreement with experiential knowledge possessed by practicing examiners. Further comparisons between scores produced by the algorithm and visual assessments of the same tool mark pairs by professional tool mark examiners in a blind study in general show good agreement between the algorithm and human experts. In specific instances where the algorithm had difficulty in assessing a particular comparison pair, results obtained during the collaborative study with professional examiners suggest ways in which algorithm performance may be improved. It is concluded that the addition of contextual information when inputting data into the algorithm should result in better performance. ABSTRACT: A statistical analysis and computational algorithm for comparing pairs of tool marks via profilometry data is described. This analysis is superior to ad hoc comparisons based

This research involves using molten magnesium (Mg) to remove neodymium (Nd) from NdFeB magnet scrap by diffusion. Mg was melted over pieces of NdFeB scrap and held at temperatures in the range 675-705 °C for 2-8 h. The Mg was allowed to solidify, and the castings were then sectioned and characterized using scanning electron microscopy, x-ray diffraction, and chemical analysis. Nd was found to have diffused out of the solid scrap into the molten Mg. The thickness of the diffusion layer was measured, the diffusion of Nd through the NdFeB scrap into liquid Mg was described, and the diffusion coefficient of Nd in liquid Mg was estimated. This research involves using molten magnesium (Mg) to remove neodymium (Nd) from NdFeB magnet scrap by diffusion. Mg was melted over pieces of NdFeB scrap and held at temperatures in the range 675-705°C for 2-8 h. The Mg was allowed to solidify, and the castings were then sectioned and characterized using scanning electron microscopy, x-ray diffraction, and chemical analysis. Nd was found to have diffused out of the solid scrap into the molten Mg. The thickness of the diffusion layer was measured, the diffusion of Nd through the NdFeB scrap into liquid Mg was described, and the diffusion coefficient of Nd in liquid Mg was estimated.

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A combined resistivity transmission electron microscopy (TEM) study has been done on heavily drawn en-20 vol % Nb alloys (so-called in situ alloys). The results show that electron scattering at Cu-Nb interfaces makes the major contribution to resistivity in heavily drawn wire. The dislocation contribution is small and constant at deformation strains greater than around 4, apparently as a result of dynamic recovery/recrystallization of the Cu matrix which occurs during room-temperature drawing. Results of this study and other recent TEM dislocation studies indicate that the dislocation density in heavily drawn Cu-20 vol % Nb material does not exceed 1011 cm-2 • It is demonstrated here that the 1013_ cm-2 dislocation density predicted by the resistivity study of Karasek and Bevk [J. App!. Phys. 52, 1370 ( 1981 )] is high because the interface scattering contribution is more strongly reduced by coarsening than they assumed. It is shown that resistivity measurements provide a means of evaluating an average Cu channel diameter in the aligned composite alloys formed at large deformation strains.FIG~ L Resistivity vs temperature. Upper curve is for Cu-20 vol % Nb (no preannea!) at 17 = IO~ 9 ~ Lower curve is for pure Cu at 7/ = 1O~ 9 ~ 1293

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