Publications associées à Cratère de Chicxulub

Hot rocks: Constraining the thermal conditions of the Mistastin Lake impact melt deposits using zircon grain microstructures

The production of superheated melt during hypervelocity impact events has been proposed to be a common occurrence on terrestrial planetary bodies. Recent direct evidence of superheated impact melt temperatures exceeding > 2370 degrees C from the Kamestasti ...

ELSEVIER2022

State-to-state methane-surface scattering as a probe of catalytic activity

Rainer Beck, Maarten Eduard van Reijzen, Bo-Jung Chen, Jörn Werdecker

Quantum state-resolved scattering experiments for methane molecules colliding with a catalytically active nickel surface are compared to scattering from a nickel surface passivated by a single layer of graphene. The vibrational state distribution of the sc ...

2020

Shock-produced high-pressure (La, Ce, Th)PO4 polymorph revealed by microstructural phase heritage of monazite

Cyril Cayron

The responses of uranium-bearing accessory minerals to shock metamorphism have received growing interest, because under extreme pressure and temperature conditions, these phases can form unique microstructures and/or polymorphs and their radiometric ages c ...

GEOLOGICAL SOC AMER, INC2019

Methane dissociation on the steps and terraces of Pt(211) resolved by quantum state and impact site

Rainer Beck, Helen Jane Chadwick, Ana Gutiérrez González

Methane dissociation on the step and terrace sites of a Pt(211) single crystal was studied by reflection absorption infrared spectroscopy (RAIRS) at a surface temperature of 120 K. The C−H stretch RAIRS signal of the chemisorbed methyl product species was ...

American Institute of Physics2018

Cubic zirconia in >2370◦C impact melt records Earth’s hottest crust

Cyril Cayron

Bolide impacts influence primordial evolution of planetary bodies because they can cause instantaneous melting and vaporization of both crust and impactors. Temperatures reached by impact-generated silicate melts are unknown because meteorite impacts are e ...

Elsevier2017

Notch as a tumour suppressor

Freddy Radtke, Craig Nowell

The Notch signalling cascade is an evolutionarily conserved pathway that has a crucial role in regulating development and homeostasis in various tissues. The cellular processes and events that it controls are diverse, and continued investigation over recen ...

Nature Publishing Group2017

Temporal variability of secondary processes in alkaline geothermal waters associated to granitic rocks: the Caldes de Boi geothermal system (Spain)

Maria Pilar Asta Andres

The Caldes de Boi geothermal waters show important differences in pH (6.5-9.6) and temperature (15.9 degrees C-52 degrees C) despite they have a common origin and a very simple circuit at depth (4km below the recharge area level). These differences are the ...

Univ Barcelona2017

A deep crust-mantle boundary in the asteroid 4 Vesta

Philippe Gillet, Harold Gabriel Eugène Justin Clenet

The asteroid 4 Vesta was recently found to have two large impact craters near its south pole, exposing subsurface material. Modelling suggested that surface material in the northern hemisphere of Vesta came from a depth of about 20 kilometres, whereas the ...

Nature Publishing Group2014

The structure of the asteroid 4 Vesta as revealed by models of planet-scale collisions

Philippe Gillet

Asteroid 4 Vesta seems to be a major intact protoplanet, with a surface composition similar to that of the HED (howardite-eucrite-diogenite) meteorites(1-4). The southern hemisphere is dominated by a giant impact scar(5), but previous impact models(6-8) ha ...

Nature Publishing Group2013

Cavitation in impacted drops and jets and the effect on erosion damage thresholds

Mohamed Farhat, Danail Obreschkow, Marc Tinguely

It is well known that metals and alloys erode at lower impact threshold velocities than expected. This was studied by Thomas and Brunton (1970) who reported “discrepancy factors” in the range 4–10. These authors suggested that liquid impact was a more sear ...

Elsevier Science Sa2012

Pre-Columbian deforestation as an amplifier of drought in Mesoamerica

Jed Oliver Kaplan

Droughts in pre-Columbian Mesoamerica caused significant societal disruptions during the Late Classic and Post-Classic Periods. While the primary causes of these droughts are still debated, it has been speculated that they may be linked to extensive defore ...

Amer Geophysical Union2012

Pollution transport efficiency toward the Arctic: Sensitivity to aerosol scavenging and source regions

Isabelle Bey, Quentin Bourgeois

The processes driving current changes in Arctic atmospheric composition and climate are still uncertain. In particular the relative contributions of major source regions from the midlatitudes remain a matter of debate in the literature. The objectives of t ...

2011

State-resolved reactivity of CH4 on Pt(110)-(1 x 2): The role of surface orientation and impact site

Rainer Beck, Régis Bisson, Marco Sacchi

The reactivity of methane (CH4) on Pt(110)-(1×2) has been studied by quantum state-resolved surface reactivity measurements. Ground state reaction probabilities, S0(v=0) ~ S0(laser-off), as well as state-resolved reaction probabilities S0(2v3), for CH4 exc ...

2010

Active sensing and repair composites

Eva Kirkby

This thesis describes the development of a smart carbon fibre polymer composite that is capable of sensing its own damage and self-healing. Structural composites are used in the aerospace and marine industries, for example. During their lifetime impact eve ...

EPFL2009

The influence of pool geometry and induced flow patterns in rock scour by high-velocity plunging jets

Pedro Filipe De Almeida Manso

The dissipation of energy of flood discharges from water releasing structures of dams is often done by plunging jets diffusing in water and impacting on the riverbed downstream. The construction of expensive concrete structures for energy dissipation can b ...

EPFL2006