11,473 research outputs found
Experimental creep data for a built-up aluminum/titanium structure subjected to heating and loading
Experimental creep, temperature, and strain data resulting from a laboratory experiment on a built-up aluminum/titanium structure are presented. The structure and the experiment are described in detail. A heating and loading experiment lasting approximately six hours is conducted on a test structure. Considerable creep strain resulted from compressive stresses in the heated skin. Large residual stresses were found after the experiment was completed. The residual stresses in the substructure frames were large enough to preclude further cycles of creep experiments with this built-up structure because of concern that the frame webs would buckle
Long-range correlations and trends in Colombian seismic time series
We study long-range correlations and trends in time series extracted from the
data of seismic events occurred from 1973 to 2011 in a rectangular region that
contains mainly all the continental part of Colombia. The long-range
correlations are detected by the calculation of the Hurst exponents for the
time series of interevent intervals, separation distances, depth differences
and magnitude differences. By using a modification of the classical
method that has been developed to detect short-range correlations in time
series, we find the existence of persistence for all the time series considered
except for magnitude differences. We find also, by using the until the
third order, that the studied time series are not influenced by trends.
Additionally, an analysis of the Hurst exponent as a function of the number of
events in the time and the maximum window size is presented.Comment: 21 pages, 6 figures, 2 figures added, types corrected, accepted to be
published in Physica
The Bak-Sneppen Model on Scale-Free Networks
We investigate by numerical simulations and analytical calculations the
Bak-Sneppen model for biological evolution in scale-free networks. By using
large scale numerical simulations, we study the avalanche size distribution and
the activity time behavior at nodes with different connectivities. We argue the
absence of a critical barrier and its associated critical behavior for infinite
size systems. These findings are supported by a single site mean-field analytic
treatment of the model.Comment: 5 pages and 3 eps figures. Final version appeared in Europhys. Let
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Bioinspired snapping-claw apparatus to study hydrodynamic cavitation effects on the corrosion of metallic samples
A creative low-cost and compact mechanical device that mimics the rapid closure of the pistol shrimp claw was used to conduct electrochemical experiments, in order to study the effects of hydrodynamic cavitation on the corrosion of aluminum and steel samples. Current-time curves show significant changes associated with local variations in dissolved O2 concentration, cavitation-induced erosion and changes in the nature of the surface corrosion products
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