58 research outputs found

    Temperature influence on water transport in hardened cement pastes

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    International audienceDescribing water transport in concrete is an important issue for the durability assessment of radioactive wastemanagement reinforced concrete structures. Due to the waste thermal output such structures would besubmitted to moderate temperatures (up to 80 °C). We have then studied the influence of temperature onwater transport within hardened cement pastes of four different formulations. Using a simplified approach(describing only the permeation of liquid water) we characterized the properties needed to describe watertransport (up to 80 °C) using dedicated experiments. For each hardened cement paste the results are presentedand discussed

    Simultaneous inversion of source spectra, attenuation parameters and site responses. Application to the data of the French Accelerometric Network.

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    International audienceDisplacement spectra of earthquakes recorded by the French accelerometric network at regional scale are modeled as the product of source, propagation (including geometric and anelastic attenuation), and site effects. We use an iterative Gauss–Newton inversion to solve the nonlinear problem and retrieve these different terms. This method is easy to implement because the partial derivatives of the amplitude spectrum with respect to the different parameters have simple analytic forms. After convergence, we linearize the problem around the solution to compute the correlation matrix, which allows us to identify the parameters which are poorly resolved. We analyze data from two tectonically active regions: the Alps and the Pyrenees. Eighty-three earthquakes with local magnitudes between 3.0 and 5.3 are analyzed, with epicentral distances in the range 15–200 km. S-wave displacement spectra are computed using a fast Fourier transform and integration in the 0.5–15-Hz frequency domain. We assume a Brune-type source, with a geometric attenuation of the form R-{gamma}, {gamma} being constant, and a frequency-dependent quality factor of the form Q=Q0xf{alpha}. The results reveal that the attenuation parameters are correlated to each other and to the seismic moments. The two regions have different attenuation patterns. The geometrical spreading factor is equal to 1 for the Alps and 1.2 for the Pyrenees. The anelastic attenuation exhibits low Q0 values (322 and 376 for the Alps and the Pyrenees, respectively) with regional variations for {alpha} (0.21 in the Alps and 0.46 in the Pyrenees). Computed moment magnitudes are generally 0.5 unit smaller than local magnitudes, and the logarithms of the corner frequencies decrease linearly with magnitude according to log10(fc)=1.72-0.32xMw. Stress drops range from 105 to 107 Pa (i.e., 1–100 bars), with a slight dependence to magnitude (large stress drops for large magnitudes). Finally, robust site responses relative to an average rock-site response are derived, allowing us to identify good reference rock sites

    Hydroxyapatite coating on titanium by a low energy plasma spraying mini-gun

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    Plasma-sprayed hydroxyapatite (HA) coatings are used on metallic implants to improve osseointegration and bone growth. The purpose of this work was to determine the microstructure and composition of HA coatings obtained with a newly developed low energy plasma spray mini-gun employing an HA feedstock powder with smaller granulometry than that commonly used. The microstructure and the phase composition of the coatings obtained by varying the number of mini-gun runs were examined using scanning electron microscopy, X-ray diffraction and Fourier transform infrared and micro-Raman spectroscopy. In all cases, the results indicate the presence of an amorphous phase and oxyapatite in the coatings due to hydroxyl group removal. No other foreign crystalline phases were detected. The absence of foreign phases was attributed to the fast cooling rate of the small particles used in the experiments and the low amount of energy employed with the mini-gun. Decomposition in the υ1PO4 region of the Raman spectra allowed a semi-quantitative evaluation of the phase contents as a function of the number of runs. Micro-Raman spectroscopy appears to be a powerful technique providing comprehensive and localised information concerning calcium phosphate phases in coatings

    Toward a ground-motion logic tree for probabilistic seismic hazard assessment in Europe

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    The Seismic Hazard Harmonization in Europe (SHARE) project, which began in June 2009, aims at establishing new standards for probabilistic seismic hazard assessment in the Euro-Mediterranean region. In this context, a logic tree for ground-motion prediction in Europe has been constructed. Ground-motion prediction equations (GMPEs) and weights have been determined so that the logic tree captures epistemic uncertainty in ground-motion prediction for six different tectonic regimes in Europe. Here we present the strategy that we adopted to build such a logic tree. This strategy has the particularity of combining two complementary and independent approaches: expert judgment and data testing. A set of six experts was asked to weight pre-selected GMPEs while the ability of these GMPEs to predict available data was evaluated with the method of Scherbaum et al. (Bull Seismol Soc Am 99:3234-3247, 2009). Results of both approaches were taken into account to commonly select the smallest set of GMPEs to capture the uncertainty in ground-motion prediction in Europe. For stable continental regions, two models, both from eastern North America, have been selected for shields, and three GMPEs from active shallow crustal regions have been added for continental crust. For subduction zones, four models, all non-European, have been chosen. Finally, for active shallow crustal regions, we selected four models, each of them from a different host region but only two of them were kept for long periods. In most cases, a common agreement has been also reached for the weights. In case of divergence, a sensitivity analysis of the weights on the seismic hazard has been conducted, showing that once the GMPEs have been selected, the associated set of weights has a smaller influence on the hazar

    Understanding the physics of kappa (Îș): Insights from a downhole array

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    At high frequencies, the acceleration spectral amplitude decreases rapidly; this has been modelled with the spectral decay factor Îș. Its site component, Îș0, is used widely today in ground motion prediction and simulation, and numerous approaches have been proposed to compute it. In this study, we estimate Îș for the EUROSEISTEST valley, a geologically complex and seismically active region with a permanent strong motion array consisting of 14 surface and 6 downhole stations. Site conditions range from soft sediments to hard rock. First, we use the classical approach to separate local and regional attenuation and measure Îș0. Second, we take advantage of the existing knowledge of the geological profile and material properties to examine the correlation of Îș0 with different site characterization parameters. Îș0 correlates well with Vs30, as expected, indicating a strong effect from the geological structure in the upper 30 m. But it correlates equally well with the resonant frequency and depth-to-bedrock of the stations, which indicates strong effects from the entire sedimentary column, down to 400 m. Third, we use our results to improve our physical understanding of Îș0. We propose a conceptual model of Îș0 with Vs, comprising two new notions. On the one hand, and contrary to existing correlations, we observe that Îș0 stabilizes for high Vs values. This may indicate the existence of regional values for hard rock Îș0. If so, we propose that borehole measurements (almost never used up to now for Îș0) may be useful in determining these values. On the other hand, we find that material damping, as expressed through travel times, may not suffice to account for the total Îș0 measured at the surface. We propose that, apart from material damping, additional site attenuation may be caused by scattering from small-scale variability in the profile. If this is so, then geotechnical damping measurements may not suffice to infer the overall crustal attenuation under a site; but starting with a regional value (possibly from a borehole) and adding damping, we might define a lower bound for site-specific Îș0. More precise estimates would necessitate seismological site instrumentation

    Profiling the landscape of transcription, chromatin accessibility and chromosome conformation of cattle, pig, chicken and goat genomes [FAANG pilot project]

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    Functional annotation of livestock genomes is a critical and obvious next step to derive maximum benefit for agriculture, animal science, animal welfare and human health. The aim of the Fr-AgENCODE project is to generate multi-species functional genome annotations by applying high-throughput molecular assays on three target tissues/cells relevant to the study of immune and metabolic traits. An extensive collection of stored samples from other tissues is available for further use (FAANG Biosamples ‘FR-AGENCODE’). From each of two males and two females per species (pig, cattle, goat, chicken), strand-oriented RNA-seq and chromatin accessibility ATAC-seq assays were performed on liver tissue and on two T-cell types (CD3+CD4+&CD3+CD8+) sorted from blood (mammals) or spleen (chicken). Chromosome Conformation Capture (in situ Hi-C) was also carried out on liver. Sequencing reads from the 3 assays were processed using standard processing pipelines. While most (50–70%) RNA-seq reads mapped to annotated exons, thousands of novel transcripts and genes were found, including extensions of annotated protein-coding genes and new lncRNAs (see abstract #69857). Consistency of ATAC-seq results was confirmed by the significant proportion of called peaks in promoter regions (36–66%) and by the specific accumulation pattern of peaks around gene starts (TSS) v. gene ends (TTS). Principal Component Analyses for RNA-seq (based on quantified gene expression) and ATAC-seq (based on quantified chromatin accessibility) highlighted clusters characterised by cell type and sex in all species. From Hi-C data, we generated 40kb-resolution interaction maps, profiled a genome-wide Directionality Index and identified from 4,100 (chicken) to 12,100 (pig) topologically-associating do- mains (TADs). Correlations were reported between RNA-seq and ATAC-seq results (see abstract #71581). In summary, we present here an overview of the first multi-species and -tissue annotations of chromatin accessibility and genome architecture related to gene expression for farm animals

    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

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    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & NemĂ©sio 2007; Donegan 2008, 2009; NemĂ©sio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

    Analyse des données accélérométriques pour la caractérisation de l'aléa sismique en France métropolitaine

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    This work is devoted to the analysis of the accelerometric data from French metropolitan territory, recorded by the National Accelerometric Network (Réseau Accélérométrique Permanent, RAP), the deployment of which is under way since 1996, in order to provide elements for seismic hazard studies. A number of empirical strong ground motion models exists based on data from seismically active regions (USA, Japan...), but reevaluation of key parameters such as magnitudes or site effects is required in order to use these models in the French context.First, the study of the moderate events data allows us to determine a homogeneous magnitude scale based on the seismic moment. Site responses for the RAP stations in the Pyrenees, the Alps and the Rhine Graben have also been computed. Attenuation models exhibit regional variations in France. Based on the previous results and on the data from the major events recorded by the RAP, empirical strong ground motion models suitable for France have been identified.Ce travail est consacré à l'étude des données accélérométriques de la france métropolitaine, issues du Réseau Accélérométrique Permanent (RAP), en cours d'installation depuis 1996, pour caractériser l'aléa sismique. Il existe de nombreux modÚles empiriques de prédiction des mouvements forts valables pour les régions sismiquement trÚs actives (USA, Japon...), mais leur utilisation dans le contexte français nécessite la ré-évaluation de paramÚtres tels que les magnitudes et les conditions de site.Dans un premier temps, l'analyse des données de séismes modérés a permis d'établir une échelle homogÚne de magnitudes issues du moment sismique. Par ailleurs, les réponses de site des stations du réseau RAP ont été calculées pour les Pyrénées, les Alpes et le fossé Rhénan. Enfin, les phénomÚnes d'atténuation au niveau de la France semblent présenter des variations régionales. En se basant sur les résultats précédents, l'applicabilité de certains modÚles empiriques de mouvements forts a été démontrée, à partir des séismes les plus importants enregistés par le RA

    Santé et environnement en France : deux siÚcles de « symbiose » juridique (1802-2002)

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    Two hundred years have passed between the creation of the ComitĂ© de salubritĂ© (HygiĂšne Committee) in the Seine Department in 1802 and the promulgation of the Law of March 4, 2002 on the Modernization of the Health System, during which French law has closely associated provisions relating to public health to provisions relating to the protection of the natural environment. The centenary of the law of February 15, 1902, a major public health charter, was the occasion of recalling this juridical « symbiosis ». Looking back, it appears that the law relating to public hygiene and public health was the matrix of the environmental law that was to be born in the sixties and seventies. The progress of ecological values has contributed to provide a firm basis to public health law, ever since. At the beginning of the Jd millennium, lawyers must continue to think of medical care organization in terms of ecological values and to imagine what a « health ecosystem » might be.Entre la crĂ©ation du Conseil de salubritĂ© de la Seine en 1802 et la promulgation de la loi du 4 mars 2002 sur la modernisation de la santĂ©, il s'est Ă©coulĂ© deux cents ans au cours desquels le droit français a Ă©troitement mĂȘlĂ© des dispositions sur la santĂ© publique et la protection du milieu naturel. Le centenaire de la loi du 15 fĂ©vrier 1902, grande charte sanitaire, a Ă©tĂ© l'occasion de rappeler ce phĂ©nomĂšne de « symbiose » juridique. Avec le recul du temps, il apparaĂźt en effet que le droit de l'hygiĂšne et de la salubritĂ© publiques a servi de « matrice » Ă  un droit de l'environnement qui ne naĂźtra que dans les annĂ©es soixante et soixante-dix. GrĂące Ă  l'avancĂ©e des prĂ©occupations Ă©cologistes depuis, celui-ci a permis de consolider durablement les bases du droit de la santĂ©. A l'aube du troisiĂšme millĂ©naire, les juristes devront continuer Ă  repenser l'organisation des soins autour des valeurs de l'Ă©cologie, et imaginer en quelque sorte un « Ă©cosystĂšme de santĂ© ».Drouet StĂ©phane. SantĂ© et environnement en France : deux siĂšcles de « symbiose » juridique (1802-2002). In: Revue Juridique de l'Environnement, n°3, 2003. pp. 319-338

    vS30, Îș, regional attenuation and Mw from accelerograms: application to magnitude 3-5 French earthquakes

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    International audienceWe investigate recordings from weak to moderate earthquakes, with magnitudes ranging between about 3 and 5, recorded by the French Accelerometric Network. S-wave spectra are modelled as a product of source, propagation and site terms. Inverting large data sets of multiple earthquakes recorded at multiple stations allows us to separate the three contributions. Source parameters such as moment magnitude, corner frequency and stress drop are estimated for each earthquake. We provide the first complete and homogeneous catalogue of moment magnitudes for France, for the events with magnitude greater than 3 that occurred between 1996 and 2006. Stress drops are found to be regionally dependent as well as magnitude dependent, and range from about 0.1 MPa (1 bar) to about 30 MPa (300 bars). The attenuation parameters show that, in France on a nationwide scale, variations of attenuation properties do exist. Site transfer functions are also computed, giving the level of amplification at different frequencies with respect to the response of a generic rock site (characterized by an average 30 m S-wave velocity, vs30, of 2000ms-1). From these site terms, we compute the high-frequency fall-off parameter Îș [modelled as exp (-πÎșf), with f the frequency] for 76 stations. We also determine rock stations vs30 and we show the Îș-vs30 relationship for 21 rock stations
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