A simple derivation of BV bounds for inhomogeneous relaxation systems

We consider relaxation systems of transport equations with heterogeneous source terms and with boundary conditions, which limits are scalar conservation laws. Classical bounds fail in this context and in particular BV estimates. They are the most standard and simplest way to prove compactness and convergence. We provide a novel and simple method to obtain partial BV regularity and strong compactness in this framework. The standard notion of entropy is not convenient either and we also indicate another, but closely related, notion. We give two examples motivated by renal flows which consist of 2 by 2 and 3 by 3 relaxation systems with 2-velocities but the method is more general

Structural properties of a calcium aluminosilicate glass from molecular-dynamics simulations: A finite size effects study

We study a calcium aluminosilicate glass of composition (SiO$_2$)$_{0.67}$-(Al$_2$O$_3$)$_{0.12}$-(CaO)$_{0.21}$ by means of molecular-dynamics (MD) simulations, using a potential made of two-body and three-body interactions. In order to prepare small samples that can subsequently be studied by first-principles, the finite size effects on the liquid dynamics and on the glass structural properties are investigated. We find that finite size effects affect the Si-O-Si and Si-O-Al angular distributions, the first peaks of the Si-O, Al-O and Ca-O pair correlation functions, the Ca coordination and the oxygen atoms environment in the smallest system (100 atoms). We give evidence that these finite size effects can be directly attributed to the use of three-body interactions.Comment: 36 pages, 14 figures. Journal of Chem. Phys., in pres

First-principles molecular-dynamics simulations of a hydrous silica melt: Structural properties and hydrogen diffusion mechanism

We use {\it ab initio} molecular dynamics simulations to study a sample of liquid silica containing 3.84 wt.% H$_2$O.We find that, for temperatures of 3000 K and 3500 K,water is almost exclusively dissolved as hydroxyl groups, the silica network is partially broken and static and dynamical properties of the silica network change considerably upon the addition of water.Water molecules or free O-H groups occur only at the highest temperature but are not stable and disintegrate rapidly.Structural properties of this system are compared to those of pure silica and sodium tetrasilicate melts at equivalent temperatures. These comparisons confirm the picture of a partially broken tetrahedral network in the hydrous liquid and suggest that the structure of the matrix is as much changed by the addition of water than it is by the addition of the same amount (in mole %) of sodium oxide. On larger length scales, correlations are qualitatively similar but seem to be more pronounced in the hydrous silica liquid. Finally, we study the diffusion mechanisms of the hydrogen atoms in the melt. It turns out that HOSi$_2$ triclusters and SiO dangling bonds play a decisive role as intermediate states for the hydrogen diffusion.Comment: 25 pages, 18 figures. submitte

Ion Beam Radiation Effects in Monazite.

International audienceMonazite is a potential matrix for conditioning minor actinides arising from spent fuel reprocessing. The matrix behavior under irradiation must be investigated to ensure long-term containment performance. Monazite compounds were irradiated by gold and helium ions to simulate the consequences of alpha decay. This article describes the effects of such irradiation on the structural and macroscopic properties (density, hardness) of monazites LaPO4 and La0.73Ce0.27PO4. Irradiation by gold ions results in major changes in the material properties. At a damage level of 6.7 dpa, monazite exhibits volume expansion of about 8.1%, a 59% drop in hardness, and structure amorphization, although Raman spectroscopy analysis shows that the phosphate-oxygen bond is unaffected. Conversely, no change in the properties of these compounds was observed after He ion implantation. These results indicate that ballistic effects predominate in the studied dose range

La construction sociale du marché du handicap : entre concurrence associative et régulation politique (1943-2009)

Les équipements du secteur du handicap sont gérés en France par des acteurs associatifs, qui représentent les trois quarts des opérateurs. Essentiellement financées par des fonds publics, ces organisations privées agissent selon des règles propres au secteur. Mais l'introduction des appels à projets (loi HPST de 2009) cristallise les débats sur la création d'un " marché du handicap " et l'instauration d'une logique concurrentielle entre les associations. Prenant de la distance à l'égard de ces débats, l'objectif de la recherche est de proposer une analyse des processus de transformations des comportements économiques des associations dans le secteur du handicap que nous avons considéré comme un champ organisationnel. Adoptant une approche longitudinale à l'aide d'une part d'une enquête sur les données de l'évolution de l'équipement dans deux départements de la région Rhône-Alpes depuis les années quarante et d'autre part d'une enquête par entretiens auprès d'une soixantaine d'acteurs du champ, cette recherche met en évidence trois résultats. (1) Les luttes concurrentielles, même si elles ont toujours existé dans le champ connaissent des évolutions dans le temps. D'une part elles s'intensifient dans le sens où les opérateurs associatifs s'implantent sur des territoires de concurrence occupés par d'autres et que des ententes implicites protégeaient jusque là de toute nouvelle intrusion. D'autre part, de nouvelles stratégies de lutte concurrentielle émergent : actions sur les coûts et la qualité et prise de contrôle directe sur d'autres opérateurs dans le cadre de fusions-acquisitions (2) Ces nouvelles formes de luttes économiques se diffusent car elles sont soutenues par une nouvelle conception de contrôle " managériale " en émergence qui valorise les comportements de recherche d'efficience, de rationalisation et de rapprochement associatifs. Cette conception de contrôle est soutenue par de nouveaux acteurs clés du champ, issus eux-mêmes des transformations des rapports de pouvoir interne aux opérateurs associatifs (la prise de pouvoir des dirigeants salariés, professionnels de la gestion, sur les dirigeants bénévoles) et des transformations des modes d'intervention des autorités publiques (instruments de contrôle à distance mobilisés par les représentants des autorités publiques). (3) Ces nouvelles formes de lutte économiques ont des effets de stabilisation des rapports de pouvoir dans le champ, autrement dit des positions acquises au cours de la première phase de structuration du champ. Ce travail pourrait ouvrir plusieurs perspectives de recherche. La principale consiste en une exploitation approfondie des données statistiques que nous avons recueillies pour constituer une base de données longitudinales sur l'offre d'équipement dans deux départements de manière à mieux rendre compte des transformations qui affectent les luttes concurrentielles entre opérateurs associatifs. Ce travail soulève par ailleurs des questions sur la façon dont l'information sur l'équipement dans le secteur du handicap est construite et utilisée par les acteurs. Des recherches sur la construction et les usages des nomenclatures officielles (de type FINESS) et leur articulation avec les classements " indigènes " produits par les acteurs de terrain peuvent notamment aider à comprendre certains décalages entre les " besoins " et les équipements créés

Diagnóstico de las nuevas tecnologías empleadas para el diseño de mezclas asfálticas densas en caliente MDC-2

El presente trabajo pretende brindar alternativas de modificación de las Mezclas Asfálticas Densas en Caliente, empleadas para la pavimentación de las vías en Colombia, mecanismos que actualmente generan un impacto ambiental negativo debido a la utilización de los materiales pétreos, los cuales debido a su ubicación no cumplen con las especificaciones técnicas o son de difícil acceso en algunas zonas de nuestro país. Es por ello que estudios realizados han demostrado que la fabricación de mezclas con asfalto convencional no han sido suficientes para soportar la acción del tránsito y el clima, por lo tanto se ha recomendado emplear modificadores o aditivos en las mezclas, con el fin de mejorar las características o propiedades geológicas tanto del cemento asfáltico como de las mezclas asfálticas, así como emplear desechos de materiales que generan un alto impacto en el ambiente

Sepsis and septic shock in patients with malignancies : a Groupe de Recherche Respiratoire en Réanimation Onco-Hématologique study

Objectives: Cancer affects up to 20% of critically ill patients, and sepsis is one of the leading reasons for ICU admission in this setting. Early signals suggested that survival might be increasing in this population. However, confirmation studies have been lacking. The goal of this study was to assess trends in survival rates over time in cancer patients admitted to the ICU for sepsis or septic shock over the last 2 decades. Data Source: Seven European ICUs. Study Selection: A hierarchical model taking into account the year of admission and the source dataset as random variables was used to identify risk factors for day 30 mortality. Data Extraction: Data from cancer patients admitted to ICUs for sepsis or septic shock were extracted from the Groupe de Recherche Respiratoire en Reanimation Onco-Hematologique database (1994-2015). Data Synthesis: Overall, 2,062 patients (62% men, median [interquartile range] age 59 yr [48-67 yr]) were included in the study. Underlying malignancies were solid tumors (n = 362; 17.6%) or hematologic malignancies (n = 1,700; 82.4%), including acute leukemia (n = 591; 28.7%), non-Hodgkin lymphoma (n = 461; 22.3%), and myeloma (n = 244; 11.8%). Two-hundred fifty patients (12%) underwent allogeneic hematopoietic stem cell transplantation and 640 (31.0%) were neutropenic at ICU admission. Day 30 mortality was 39.9% (823 deaths). The year of ICU admission was associated with significant decrease in day 30 mortality over time (odds ratio, 0.96; 95% CI, 0.93-0.98; p = 0.001). Mechanical ventilation (odds ratio, 3.25; 95% CI, 2.52-4.19; p < 0.01) and vasopressors use (odds ratio, 1.42; 95% CI, 1.10-1.83; p < 0.01) were independently associated with day 30 mortality, whereas underlying malignancy, allogeneic hematopoietic stem cell transplantation, and neutropenia were not. Conclusions: Survival in critically ill oncology and hematology patients with sepsis improved significantly over time. As outcomes improve, clinicians should consider updating admission policies and goals of care in this population

Signature of small rings in the Raman spectra of normal and compressed amorphous silica: A combined classical and ab initio study

We calculate the parallel (VV) and perpendicular (VH) polarized Raman spectra of amorphous silica. Model SiO2 glasses, uncompressed and compressed, were generated by a combination of classical and ab initio molecular-dynamics simulations and their dynamical matrices were computed within the framework of the density functional theory. The Raman scattering intensities were determined using the bond-polarizability model and a good agreement with experimental spectra was found. We confirm that the modes associated to the fourfold and threefold rings produce most of the Raman intensity of the D1 and D2 peaks, respectively, in the VV Raman spectra. Modifications of the Raman spectra upon compression are found to be in agreement with experimental data. We show that the modes associated to the fourfold rings still exist upon compression but do not produce a strong Raman intensity, whereas the ones associated to the threefold rings do. This result strongly suggests that the area under the D1 and D2 peaks is not directly proportional to the concentration of small rings in amorphous SiO2.Comment: 21 pages, 8 figures. Phys. Rev. B, in pres

Large-scale morphodynamics structures in the Arc en Maurienne River (France)

Water Qualit

Decision Support Framework Using Knowledge Based Digital Twin for Sustainable Product Development and End of Life

In order to have a sustainable disassembly process, a successful decision-making based on reliable and up-to-date information should be made while taking into consideration sustainability indicators. In this context, The aim of this paper is to introduce a decision support system based on knowledge based and digital twin in order to help stakeholders to choose the most sustainable disassembly scenario .In this research, firstly, we presented the state of art of disassembly process, digital twin, knowledge based system and the merging of knowledge based system and digital twin for disassembly. Secondly, we presented the knowledge based digital twin (KBDTw) system framework for a sustainable disassembly process. Thirdly, a case study is presented about the use of KBDTw in the end-of-life of internet boxes. Finally, a conclusion and future work are conducted.publishedVersio