410 research outputs found

    Baryon polarization in low-energy unpolarized meson-baryon scattering

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    We compute the polarization of the final-state baryon, in its rest frame, in low-energy meson--baryon scattering with unpolarized initial state, in Unitarized BChPT. Free parameters are determined by fitting total and differential cross-section data (and spin-asymmetry or polarization data if available) for pKpK^-, pK+pK^+ and pπ+p\pi^+ scattering. We also compare our results with those of leading-order BChPT

    White-etching matter in bearing steel. Part II: Distinguishing cause and effect in bearing steel failure

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    The premature failure of large bearings of the type used in wind turbines, possibly through a mechanism called “white-structure flaking”, has triggered many studies of microstructural damage associated with “white-etching areas” created during rolling contact fatigue, although whether they are symptoms or causes of failure is less clear. Therefore, some special experiments have been conducted to prove that white-etching areas are the consequence, and not the cause, of damage. By artificially introducing a fine dispersion of microcracks in the steel through heat treatment and then subjecting the sample to rolling contact fatigue, manifestations of hard white-etching matter have been created to a much greater extent than samples similarly tested without initial cracks. A wide variety of characterization tools has been used to corroborate that the white areas thus created have the same properties as reported observations on real bearings. Evidence suggests that the formation mechanism of the white-etching regions involves the rubbing and beating of the free surfaces of cracks, debonded inclusions, and voids under repeated rolling contact. It follows that the focus in avoiding early failure should be in enhancing the toughness of the bearing steel in order to avoid the initial microscopic feature event.Funding by CONACyT, the Cambridge Overseas Trust, and the Roberto Rocca Education Programme is highly appreciated and acknowledged.This is the accepted manuscript version. The final published version is available from Springer at http://link.springer.com/article/10.1007%2Fs11661-014-2431-x
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