3,238 research outputs found
The Orientation of Strain-Induced Crystallites in Uniaxially-Strained, Thin and Wide Bands Made from Natural Rubber
Vulcanized natural rubber (unfilled and filled with 20 phr carbon black) is strained. We suppress the macroscopic formation of fiber symmetry by choosing strip-shaped samples ("pure-shear geometry") and investigate the orientation of the resulting crystallites by two-dimensional wide-angle X-ray diffraction (WAXD), additionally rotating the sample tape about the straining direction. Indications of a directed reinforcing effect of the strain-induced crystallization (SIC) in the thin strip are found. In the filled material fewer crystallites are oriented and the orientation distribution of the oriented crystallites is less perfect. The results confirm, that it is important for the evaluation of crystallinity under deformation to check, whether fiber symmetry can be assumed. This has consequences in particular on the quantitative interpretation of space-resolved scanning experiments in the vicinity of crack tips. Furthermore it raises the question, whether there is an asymmetric reinforcing effect of the SIC in the vicinity of crack tips inside natural rubber. © 2019 by the authors. Licensee MDPI, Basel, Switzerland
Indexing User Uploaded Videos For Late Arriving Reference Content
Disclosed herein is a mechanism for indexing user uploaded videos. This mechanism can be used, for example, to detect unauthorized media content items in instances where the reference content is uploaded or otherwise received after the receipt of user uploaded video content. More particularly, the mechanism can create a video index of user uploaded video content or a subset of user uploaded video content that has met one or more criterion (e.g., a video that has been viewed at least a predetermined number of times) and a reference index of reference content including references files that have been activated subsequent to receiving corresponding user uploaded video content. Accordingly, activated reference content can be compared against the video index and user uploaded video content can be compared against the reference index to determine whether there is matching content
On the asymptotic behaviour of cosmic density-fluctuation power spectra
We study the small-scale asymptotic behaviour of the cosmic
density-fluctuation power spectrum in the Zel'dovich approximation. For doing
so, we extend Laplace's method in arbitrary dimensions and use it to prove that
this power spectrum necessarily develops an asymptotic tail proportional to
, irrespective of the cosmological model and the power spectrum of the
initial matter distribution. The exponent is set only by the number of
spatial dimensions. We derive the complete asymptotic series of the power
spectrum and compare the leading- and next-to-leading-order terms to derive
characteristic scales for the onset of non-linear structure formation,
independent of the cosmological model and the type of dark matter. Combined
with earlier results on the mean-field approximation for including particle
interactions, this asymptotic behaviour is likely to remain valid beyond the
Zel'dovich approximation. Due to their insensitivity to cosmological
assumptions, our results are generally applicable to particle distributions
with positions and momenta drawn from a Gaussian random field. We discuss an
analytically solvable toy model to further illustrate the formation of the
asymptotic tail.Comment: 22 pages, 4 figues, to be submitted to SciPost Physics Added
arguments to section 1 and section 5, results unchange
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