Institution
Polytechnic University of Turin
Education•Turin, Piemonte, Italy•
About: Polytechnic University of Turin is a education organization based out in Turin, Piemonte, Italy. It is known for research contribution in the topics: Finite element method & Computer science. The organization has 11553 authors who have published 41395 publications receiving 789320 citations. The organization is also known as: POLITO & Politecnico di Torino.
Topics: Finite element method, Computer science, Nonlinear system, Context (language use), Population
Papers published on a yearly basis
Papers
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TL;DR: In this article, the authors used particle flow computer code PFC2D to simulate the mechanical behavior of synthetic and rock fracture profiles during direct shear tests by using two-dimensional particle flow simulation.
Abstract: Different failure modes during fracture shearing have been introduced including normal dilation or sliding, asperity cut-off and degradation. Attempts have been made to study these mechanisms using analytical, experimental and numerical methods. However, the majority of the existing models simplify the problem, which leads to unrealistic results. With this in mind, the aim of this paper is to simulate the mechanical behaviour of synthetic and rock fracture profiles during direct shear tests by using the two-dimensional particle flow computer code PFC2D. Correlations between the simulated peak shear strength and the fracture roughness parameter DR1 recently proposed by Rasouli and Harrison (2010) are developed. Shear test simulations are carried out with PFC2D and the effects of the geometrical features as well as the model micro-properties on the fracture shear behaviour are studied. The shear strength and asperity degradation processes of synthetic profiles including triangular, sinusoidal and randomly generated profiles are analysed. Different failure modes including asperity sliding, cut-off, and asperity degradation are explicitly observed and compared with the available models. The DR1 parameter is applied to the analysis of synthetic and rock fracture profiles. Accordingly, correlations are developed between DR1 and the peak shear strength obtained from simulations and by using analytical solutions. The results are shown to be in good agreement with the basic understanding of rock fracture shear behaviour and asperity contact degradation.
137 citations
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TL;DR: In this article, a universal geometric formulation of supergravity in terms of a twisted doubled torus is proposed, which captures all known geometric fluxes and their non-geometric counterparts.
136 citations
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TL;DR: In this article, the authors proposed a new mixing length model that accounts for basicenergetic modes within the canopy sublayer (CSL) and showed that when this lengthscale model is combined with standard second-order closureschemes, first and second moments, triple velocity correlations, the mean turbulent kinetic energy dissipation rate, and the wake production are all well reproduced within the CSL provided the drag coefficient (CD) is well parameterized.
Abstract: Second-order closure models for the canopy sublayer (CSL) employ aset of closure schemes developed for `free-air' flow equations andthen add extra terms to account for canopy related processes. Muchof the current research thrust in CSL closure has focused on thesecanopy modifications. Instead of offering new closure formulationshere, we propose a new mixing length model that accounts for basicenergetic modes within the CSL. Detailed flume experiments withcylindrical rods in dense arrays to represent a rigid canopy areconducted to test the closure model. We show that when this lengthscale model is combined with standard second-order closureschemes, first and second moments, triple velocity correlations,the mean turbulent kinetic energy dissipation rate, and the wakeproduction are all well reproduced within the CSL provided thedrag coefficient (CD) is well parameterized. The maintheoretical novelty here is the analytical linkage betweengradient-diffusion closure schemes for the triple velocitycorrelation and non-local momentum transfer via cumulant expansionmethods. We showed that second-order closure models reproducereasonably well the relative importance of ejections and sweeps onmomentum transfer despite their local closure approximations.Hence, it is demonstrated that for simple canopy morphology (e.g.,cylindrical rods) with well-defined length scales, standard closureschemes can reproduce key flow statistics without much revision.When all these results are taken together, it appears that thepredictive skills of second-order closure models are not limitedby closure formulations; rather, they are limited by our abilityto independently connect the drag coefficient and the effectivemixing length to the canopy roughness density. With rapidadvancements in laser altimetry, the canopy roughness densitydistribution will become available for many terrestrialecosystems. Quantifying the sheltering effect, the homogeneity andisotropy of the drag coefficient, and more importantly, thecanonical mixing length, for such variable roughness density isstill lacking.
136 citations
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TL;DR: In this paper, the authors consider the problem of constructing a geodesic with the minimal number of free parameters such that all other geodesics are generated through isometrics, and give an intrinsic characterization of this solution in a wide class of orbits for various supergravities in different dimensions.
136 citations
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Vienna University of Technology1, Polytechnic University of Turin2, University of Barcelona3, University of Augsburg4, Academy of Sciences of the Czech Republic5, Masaryk University6, Royal Meteorological Institute7, University of Liverpool8, Stockholm University9, Norwegian Water Resources and Energy Directorate10, University of Porto11, Spanish National Research Council12, Norwegian University of Science and Technology13, National Research Council14, VRVis15, Czech Hydrometeorological Institute16, University of Freiburg17, Central Institution for Meteorology and Geodynamics18, Moscow State University19, Russian Academy of Sciences20, University of Zagreb21, University of Almería22, University of Bern23, Utrecht University24, Slovak University of Technology in Bratislava25
TL;DR: It is shown that the past three decades were among the most flood- rich periods in Europe in the past 500 years, and that this period differs from other flood-rich periods in terms of its extent, air temperatures and flood seasonality.
Abstract: There are concerns that recent climate change is altering the frequency and magnitude of river floods in an unprecedented way1. Historical studies have identified flood-rich periods in the past half millennium in various regions of Europe2. However, because of the low temporal resolution of existing datasets and the relatively low number of series, it has remained unclear whether Europe is currently in a flood-rich period from a long-term perspective. Here we analyse how recent decades compare with the flood history of Europe, using a new database composed of more than 100 high-resolution (sub-annual) historical flood series based on documentary evidence covering all major regions of Europe. We show that the past three decades were among the most flood-rich periods in Europe in the past 500 years, and that this period differs from other flood-rich periods in terms of its extent, air temperatures and flood seasonality. We identified nine flood-rich periods and associated regions. Among the periods richest in floods are 1560–1580 (western and central Europe), 1760–1800 (most of Europe), 1840–1870 (western and southern Europe) and 1990–2016 (western and central Europe). In most parts of Europe, previous flood-rich periods occurred during cooler-than-usual phases, but the current flood-rich period has been much warmer. Flood seasonality is also more pronounced in the recent period. For example, during previous flood and interflood periods, 41 per cent and 42 per cent of central European floods occurred in summer, respectively, compared with 55 per cent of floods in the recent period. The exceptional nature of the present-day flood-rich period calls for process-based tools for flood-risk assessment that capture the physical mechanisms involved, and management strategies that can incorporate the recent changes in risk. Analysis of thousands of historical documents recording floods in Europe shows that flooding characteristics in recent decades are unlike those of previous centuries.
136 citations
Authors
Showing all 11854 results
Name | H-index | Papers | Citations |
---|---|---|---|
Rodney S. Ruoff | 164 | 666 | 194902 |
Silvia Bordiga | 107 | 498 | 41413 |
Sergio Ferrara | 105 | 726 | 44507 |
Enrico Rossi | 103 | 606 | 41255 |
Stefano Passerini | 102 | 771 | 39119 |
James Barber | 102 | 642 | 42397 |
Markus J. Buehler | 95 | 609 | 33054 |
Dario Farina | 94 | 832 | 32786 |
Gabriel G. Katul | 91 | 506 | 34088 |
M. De Laurentis | 84 | 275 | 54727 |
Giuseppe Caire | 82 | 825 | 40344 |
Christophe Fraser | 76 | 264 | 29250 |
Erasmo Carrera | 75 | 829 | 23981 |
Andrea Califano | 75 | 305 | 31348 |
Massimo Inguscio | 74 | 427 | 21507 |