4,679 research outputs found
Scaling and self-similarity in an unforced flow of inviscid fluid trapped inside a viscous fluid in a Hele-Shaw cell
We investigate quasi-two-dimensional relaxation, by surface tension, of a
long straight stripe of inviscid fluid trapped inside a viscous fluid in a
Hele-Shaw cell. Combining analytical and numerical solutions, we describe the
emergence of a self-similar dumbbell shape and find non-trivial dynamic
exponents that characterize scaling behavior of the dumbbell dimensions.Comment: 4 pages, 5 figures, to appear in PR
Automated workflow for validation of ground motion simulations using conventional and complex intensity measures
This is an open-source software project that provides engineering seismologists and
structural/geotechnical earthquake engineers with an easy-to-use IM calculation and plotting
capability, seen as a critical toolchain necessary to progress the comprehensive validation of
ground motion simulation methods from the perspective of developers as well as users
Experiments of Interfacial Roughening in Hele-Shaw Flows with Weak Quenched Disorder
We have studied the kinetic roughening of an oil--air interface in a forced
imbibition experiment in a horizontal Hele--Shaw cell with quenched disorder.
Different disorder configurations, characterized by their persistence length in
the direction of growth, have been explored by varying the average interface
velocity v and the gap spacing b. Through the analysis of the rms width as a
function of time, we have measured a growth exponent beta ~= 0.5 that is almost
independent of the experimental parameters. The analysis of the roughness
exponent alpha through the power spectrum have shown different behaviors at
short (alpha_1) and long (alpha_2) length scales, separated by a crossover
wavenumber q_c. The values of the measured roughness exponents depend on
experimental parameters, but at large velocities we obtain alpha_1 ~= 1.3
independently of the disorder configuration. The dependence of the crossover
wavenumber with the experimental parameters has also been investigated,
measuring q_c ~ v^{0.47} for the shortest persistence length, in agreement with
theoretical predictions.Comment: 20 pages, 22 figure
Spatio-temporal Organization During Ventricular Fibrillation in the Human Heart
In this paper, we present a novel approach to quantify the spatio-temporal organization of electrical activation during human ventricular fibrillation (VF). We propose three different methods based on correlation analysis, graph theoretical measures and hierarchical clustering. Using the proposed approach, we quantified the level of spatio-temporal organization during three episodes of VF in ten patients, recorded using multi-electrode epicardial recordings with 30 s coronary perfusion, 150 s global myocardial ischaemia and 30 s reflow. Our findings show a steady decline in spatio-temporal organization from the onset of VF with coronary perfusion. We observed transient increases in spatio-temporal organization during global myocardial ischaemia. However, the decline in spatio-temporal organization continued during reflow. Our results were consistent across all patients, and were consistent with the numbers of phase singularities. Our findings show that the complex spatio-temporal patterns can be studied using complex network analysis
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