EvalHyd v0.1.2: a polyglot tool for the evaluation of deterministic and probabilistic streamflow predictions

The evaluation of streamflow predictions forms an essential part of most hydrological modelling studies published in the literature. The evaluation process typically involves the computation of some evaluation metrics, but it can also involve the preliminary processing of the predictions as well as the subsequent processing of the computed metrics. In order for published hydrological studies to be reproducible, these steps need to be carefully documented by the authors. The availability of a single tool performing all of these tasks would simplify not only the documentation by the authors but also the reproducibility by the readers. However, this requires such a tool to be polyglot (i.e. usable in a variety of programming languages) and openly accessible so that it can be used by everyone in the hydrological community. To this end, we developed a new tool named evalhyd that offers metrics and functionalities for the evaluation of deterministic and probabilistic streamflow predictions. It is open source, and it can be used in Python, in R, in C++, or as a command line tool. This article describes the tool and illustrates its functionalities using Global Flood Awareness System (GloFAS) reforecasts over France as an example data set.</p

Simulation laser d'impacts de particules de très grande vitesse

Le laser au néodyme du GRECO I.L.M. délivrant des impulsions de l'ordre de 100 J en quelques ns, nous a permis de simuler des impacts de micrométéorites silicatées de quelques dixièmes de μg, de vitesse comprise entre 5 et 45 km/s, sur une cible d'aluminium. Les cratères produits dans la cible sont hémisphériques, et le rapport Km, de la masse éjectée sur la masse de la particule incidente simulée, varie avec la vitesse d'impact Vp selon la loi Km = 1,17 V 1,52p

UniFHy v0.1.1: a community modelling framework for the terrestrial water cycle in Python

The land surface, hydrological, and groundwater modelling communities all have expertise in simulating the hydrological processes at play in the terrestrial component of the Earth system. However, these communities, and the wider Earth system modelling community, have largely remained distinct with limited collaboration between disciplines, hindering progress in the representation of hydrological processes in the land component of Earth system models (ESMs). In order to address key societal questions regarding the future availability of water resources and the intensity of extreme events such as floods and droughts in a changing climate, these communities must come together and build on the strengths of one another to produce next-generation land system models that are able to adequately simulate the terrestrial water cycle under change. The development of a common modelling infrastructure can contribute to stimulating cross-fertilisation by structuring and standardising the interactions. This paper presents such an infrastructure, a land system framework, which targets an intermediate level of complexity and constrains interfaces between components (and communities) and, in doing so, aims to facilitate an easier pipeline between the development of (sub-)community models and their integration, both for standalone use and for use in ESMs. This paper first outlines the conceptual design and technical capabilities of the framework; thereafter, its usage and useful characteristics are demonstrated through case studies. The main innovations presented here are (1) the interfacing constraints themselves; (2) the implementation in Python (the Unified Framework for Hydrology, unifhy); and (3) the demonstration of standalone use cases using the framework. The existing framework does not yet meet all our goals, in particular, of directly supporting integration into larger ESMs, so we conclude with the remaining limitations of the current framework and necessary future developments.</p

Factorizations of Elements in Noncommutative Rings: A Survey

We survey results on factorizations of non zero-divisors into atoms (irreducible elements) in noncommutative rings. The point of view in this survey is motivated by the commutative theory of non-unique factorizations. Topics covered include unique factorization up to order and similarity, 2-firs, and modular LCM domains, as well as UFRs and UFDs in the sense of Chatters and Jordan and generalizations thereof. We recall arithmetical invariants for the study of non-unique factorizations, and give transfer results for arithmetical invariants in matrix rings, rings of triangular matrices, and classical maximal orders as well as classical hereditary orders in central simple algebras over global fields.Comment: 50 pages, comments welcom

MICROSTRUCTURE RÉSIDUELLE D'UN ACIER 304 SOUMIS À UN CHOC LASER. INFLUENCE DU FLUX ET DE LA DURÉE D'IMPULSION LASER

L'irradiation d'une cible métallique par un laser pulsé de forte énergie génère dans le matériau, une onde de choc d'amplitude pouvant atteindre le TPa. Des cibles d'acier austénitique ont été soumises à une irradiation laser en géométrie plane ; les flux laser utilisés sont compris entre 1011 et 5.1012 W / cm2 et les durées d'impulsion laser varient entre 0,6 ns et 25 ns. Dans ces conditions d'irradiation, la pression maximum induite dans le matériau est comprise entre 10 GPa et 60 GPa. L'influence de la durée d'impulsion laser et de la pression maximum induite dans l'échantillon, sur la microstructure résiduelle (volume maclé, présence de phase α) a été étudiée par microscopie électronique en transmission ainsi que par des mesures de microdureté.Irradiation of metallic targets by high energy pulsed laser can generate in materials shock waves with amplitudes up to 1 TPa. Experiments were performed on an austenitic stainless steel with plane irradiation in the intensity range 1011 to 5.1012 W / cm2 and pulse duration at half maximum from 0.5 to 25 ns. In these conditions, the peak pressure at the front surface varies from some GPa to some tens of GPa. Microstructural changes were investigated by transmission electron microscopy in addition to microhardness measurements. The influence of the pulse duration and of the peak pressure on the metallurgical effects has been studied, in particular on microhardness, twin density and the presence of α-phase

Effects of the α-ε phase transition on wave propagation and spallation in laser shock-loaded iron

International audienc

ETUDE DU COMPORTEMENT DE L'EAU DANS LE FRONT D'UNE ONDE DE CHOC

Le travail que nous présentons est basé sur l'étude de la réflectivité d'une onde de choc d'amplitude 5,8 et 9 kbar dans l'eau. La comparaison entre les valeurs mesurées de la réflectivité et celles calculées sur la base d'un front de choc à gradient constant a permis de mettre en évidence le comportement anisotrope de l'eau dans le front de choc.This paper reports on shock front reflectivity in water at 5,8 and 9 kbar. The comparison between experimental data and calculated ones based on a constant gradient model for the shock front reveals an anisotropic behaviour of water inside the shock front

Response of iron to two symmetric laser shocks

–Laser-driven shocks provide a means of studying the dynamic behaviour of solid materials at very high strain rates. Here, we investigate the effects of a new pulsed load, generated by the crossing of two symmetric laser shocks. Both surfaces of thin iron foils are irradiated simultaneously by two high-power laser beams, producing two compressive pulses of duration about 3 ns and amplitude about 10 to 60 GPa. When they cross each other in the central region of the sample, considerable increases of the pressure and the temperature are induced, leading to twin formation and phase transition. Then, the interactions of all the incident and reflected release waves which propagate inside the sample result in various types of spall damage, depending strongly on the sample thickness and on the shock pressure. All those effects have been observed in the recovered targets, and explained by a phenomenological analysis of wave propagation. The influences of various experimental parameters have been investigated. Finally, one-dimensional computations have been performed to test the ability of a simple constitutive model, including twin formation, phase transformation and spallation, to predict the observed results. A rough agreement between computations and experiments, better at lower shock pressure, bas been obtained

COMPACTION DYNAMIQUE DE POUDRES METALLIQUES PAR CHOC LASER

Des poudres d'aluminium sont soumises à l'action d'ondes de choc engendrées par impulsion laser. Le passage de l'onde de choc à travers la poudre produit une densification et une consolidation superficielles. Les effets sont semblables à ceux produits par choc conventionnel, mais la compaction est observée sur de faibles profondeurs à cause du temps de maintien très court de la pression.Shock waves are generated by laser pulses in aluminium powder targets. The passage of the shock wave produces a densification and a consolidation of the powder on a small depth under the irradiated surface. Effets are similar to those of conventional shocks, but are observed on short distances as a consequence of the short duration of the pressure pulse