Rough infection fronts in a random medium

We study extended infection fronts advancing over a spatially uniform susceptible population by solving numerically a diffusive Kermack McKendrick SIR model with a dichotomous spatially random transmission rate, in two dimensions. We find a non-trivial dynamic critical behavior in the mean velocity, in the shape, and in the rough geometry of the displacement field of the infective front as the disorder approaches a threshold value for spatial spreading of the infection.Fil: Kolton, Alejandro Benedykt. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Laneri, Karina Fabiana. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Dynamic Critical approach to Self-Organized Criticality

A dynamic scaling Ansatz for the approach to the Self-Organized Critical (SOC) regime is proposed and tested by means of extensive simulations applied to the Bak-Sneppen model (BS), which exhibits robust SOC behavior. Considering the short-time scaling behavior of the density of sites ($\rho(t)$) below the critical value, it is shown that i) starting the dynamics with configurations such that $\rho(t=0) \to 0$ one observes an {\it initial increase} of the density with exponent $\theta = 0.12(2)$; ii) using initial configurations with $\rho(t=0) \to 1$, the density decays with exponent $\delta = 0.47(2)$. It is also shown that he temporal autocorrelation decays with exponent $C_a = 0.35(2)$. Using these, dynamically determined, critical exponents and suitable scaling relationships, all known exponents of the BS model can be obtained, e.g. the dynamical exponent $z = 2.10(5)$, the mass dimension exponent $D = 2.42(5)$, and the exponent of all returns of the activity $\tau_{ALL} = 0.39(2)$, in excellent agreement with values already accepted and obtained within the SOC regime.Comment: Rapid Communication Physical Review E in press (4 pages, 5 figures

Fire propagation visualization in real time

Our motivation comes from the need of a tailored computational tool for simulation and prediction of forest fire propagation, to be used by firefighters in Patagonia, Argentina. Based on previous works on Graphic Processing Units (GPU) for fitting and simulating fires in our region, we developed a visualization interface for real time computing, simulation and prediction of fire propagation. We have the possibility of changing the ensemble of raster maps layers to change the region in which fire will propagate. The visualization platform runs on GPUs and the user can rotate and zoom the landscape to select the optimal view of fire propagation. Opacity of different layers can be regulated by the user, allowing to see fire propagation at the same time that underlying vegetation, wind direction and intensity. The ignition point can also be selected by the user, and firebreaks can be plotted while simulation is going on. After the performance of a high number of stochastic simulations in parallel in GPUs, the application shows a map of the final fire surface colored according to the probability that a given cell burns. In this way the user can visually identify the most critical direction for fire propagation, a useful information to stop fire optimizing resources, which is specially important when they are scarce like is the case of our Patagonia region.Facultad de Informátic

Fire propagation visualization in real time

Our motivation comes from the need of a tailored computational tool for simulation and prediction of forest fire propagation, to be used by firefighters in Patagonia, Argentina. Based on previous works on Graphic Processing Units (GPU) for fitting and simulating fires in our region, we developed a visualization interface for real time computing, simulation and prediction of fire propagation. We have the possibility of changing the ensemble of raster maps layers to change the region in which fire will propagate. The visualization platform runs on GPUs and the user can rotate and zoom the landscape to select the optimal view of fire propagation. Opacity of different layers can be regulated by the user, allowing to see fire propagation at the same time that underlying vegetation, wind direction and intensity. The ignition point can also be selected by the user, and firebreaks can be plotted while simulation is going on. After the performance of a high number of stochastic simulations in parallel in GPUs, the application shows a map of the final fire surface colored according to the probability that a given cell burns. In this way the user can visually identify the most critical direction for fire propagation, a useful information to stop fire optimizing resources, which is specially important when they are scarce like is the case of our Patagonia region.Facultad de Informátic

Fire propagation visualization in real time

Our motivation comes from the need of a tailored computational tool for simulation and prediction of forest fire propagation, to be used by firefighters in Patagonia, Argentina. Based on previous works on Graphic Processing Units (GPU) for fitting and simulating fires in our region, we developed a visualization interface for real time computing, simulation and prediction of fire propagation. We have the possibility of changing the ensemble of raster maps layers to change the region in which fire will propagate. The visualization platform runs on GPUs and the user can rotate and zoom the landscape to select the optimal view of fire propagation. Opacity of different layers can be regulated by the user, allowing to see fire propagation at the same time that underlying vegetation, wind direction and intensity. The ignition point can also be selected by the user, and firebreaks can be plotted while simulation is going on. After the performance of a high number of stochastic simulations in parallel in GPUs, the application shows a map of the final fire surface colored according to the probability that a given cell burns. In this way the user can visually identify the most critical direction for fire propagation, a useful information to stop fire optimizing resources, which is specially important when they are scarce like is the case of our Patagonia region.Facultad de Informátic

Microstructural characterization and kinetics modelization of vermicular cast irons.

Several experimental techniques are used for phase identification and microstructure characterization of austempered vermicular cast irons (XRD, SEM, TEM and Mössbauer spectroscopy). Acicular structures were found to be composed by ferrite and austenite with average sizes compatible with those reported for bainitic ferrite in steels. An assessment of the free energy change involved in the austenite→bainite transformation indicated a plate-like nucleation shape for bainite with an average characteristic length close to the observed from statistical length distributions. The kinetics of the transformation was modelled in the Avrami framework. Both the diffusion controlled and the diffusionless growth hypothesis were considered in order to elucidate the mechanism underlying the austempering phase transformation

Fire Weather Index assessment and visualization

The Fire Weather Index (FWI) is extensively used in Argentina to support operative preventive measures for forest fires management. This index describes the moisture content of three different fuel types and the effect of the wind in the behaviour of fire. During last years our team developed a wildfire simulator with several functionalities requested by firefighters. In this work we report the spatial visualization of the FWI on our simulator, in order to describe the dependence of forest fire risks on FWI and fuel type of Northwest Patagonian forests in Argentina. This additional functionality allows the user to visualize the local spatial configuration of fire risk. The potential of this tool is that it would provide the FWI to be readily used in all fire stations in Argentina. Moreover, it could be taken as input information of a fire propagation model under development. In this sense, the need of modelling the impact of weather on the fuel becomes essential for the accuracy of forest fire simulations.XX Workshop Procesamiento Distribuido y Paralelo.Red de Universidades con Carreras en Informátic

Fire Weather Index assessment and visualization

The Fire Weather Index (FWI) is extensively used in Argentina to support operative preventive measures for forest fires management. This index describes the moisture content of three different fuel types and the effect of the wind in the behaviour of fire. During last years our team developed a wildfire simulator with several functionalities requested by firefighters. In this work we report the spatial visualization of the FWI on our simulator, in order to describe the dependence of forest fire risks on FWI and fuel type of Northwest Patagonian forests in Argentina. This additional functionality allows the user to visualize the local spatial configuration of fire risk. The potential of this tool is that it would provide the FWI to be readily used in all fire stations in Argentina. Moreover, it could be taken as input information of a fire propagation model under development. In this sense, the need of modelling the impact of weather on the fuel becomes essential for the accuracy of forest fire simulations.XX Workshop Procesamiento Distribuido y Paralelo.Red de Universidades con Carreras en Informátic

Fire Weather Index assessment and visualization

The Fire Weather Index (FWI) is extensively used in Argentina to support operative preventive measures for forest fires management. This index describes the moisture content of three different fuel types and the effect of the wind in the behaviour of fire. During last years our team developed a wildfire simulator with several functionalities requested by firefighters. In this work we report the spatial visualization of the FWI on our simulator, in order to describe the dependence of forest fire risks on FWI and fuel type of Northwest Patagonian forests in Argentina. This additional functionality allows the user to visualize the local spatial configuration of fire risk. The potential of this tool is that it would provide the FWI to be readily used in all fire stations in Argentina. Moreover, it could be taken as input information of a fire propagation model under development. In this sense, the need of modelling the impact of weather on the fuel becomes essential for the accuracy of forest fire simulations.XX Workshop Procesamiento Distribuido y Paralelo.Red de Universidades con Carreras en Informátic