1,720,972 research outputs found
Long-term geochemical modeling with graal 2
No full textInternational audiencePresented at the 2023 Goldschmidt conference, the GRAAL 2 model has been incorporated into the CHESS/HYTEC reactive transport code to predict the alteration of glasses used for radioactive wastes confinement [1] under geochemical disposal conditions [2]. GRAAL 2 takes into account hydrolysis, Interdiffusion, protective gel formation, secondary phases precipitation leveraging geochemical databases and reactive transport in the environment through Hytec. During the last Goldschmidt conference, the methodology for parametrizing the model and the result that can be obtained were presented. This was demonstrated through an application on two experiments performed on a simple glass of 4 oxides (SiO2 – B2O3 – Na2O – Al2O3) at 90°C in pure water [3]. An uncertainty study qualified the method and the results of the model on theses experiments. It revealed that the model’s prediction closely matched the experimental data. At the 2023 Migration conference, results for the same glass were presented, highlighting the ability to take into account variations in the solution composition and in the glass surface-to-volume ratio therefore confirming that the model was perfectly able to predict these kinds of effects.This year, after a short presentation of the model, a 25-year experiment on the same simple glass is modelled to discuss the model’s ability to predict long-term experimental results. Initially the parameters determined from last year’s experiments are used. Some discrepancies with the experiment are discussed. Then a new set of optimized parameters is proposed to drive the discussion relative to the mechanisms at work over the course of such a long experiment. To conclude, the model’s capacity, parameterization method, and results are discussed to evaluate the overall model’s performance.[1] Zanini, R., Franceschin, G., Cattaruzza, E. et al. A review of glass corrosion: the unique contribution of studying ancient glass to validate glass alteration models. npj Mater Degrad 7, 38 (2023). https://doi.org/10.1038/s41529-023-00355-4[2] Frugier, P., Minet, Y., Rajmohan, N. et al (2018). Modeling glass corrosion with GRAAL. npjMater Degrad 2, 35[3] DELCROIX, Maxime. Modelling method for glass alteration with graal2 model. In : Goldschmidt 2023 Conference. GOLDSCHMIDT, 2023
Long-term geochemical modeling with graal 2
No full textInternational audiencePresented at the 2023 Goldschmidt conference, the GRAAL 2 model has been incorporated into the CHESS/HYTEC reactive transport code to predict the alteration of glasses used for radioactive wastes confinement [1] under geochemical disposal conditions [2]. GRAAL 2 takes into account hydrolysis, Interdiffusion, protective gel formation, secondary phases precipitation leveraging geochemical databases and reactive transport in the environment through Hytec. During the last Goldschmidt conference, the methodology for parametrizing the model and the result that can be obtained were presented. This was demonstrated through an application on two experiments performed on a simple glass of 4 oxides (SiO2 – B2O3 – Na2O – Al2O3) at 90°C in pure water [3]. An uncertainty study qualified the method and the results of the model on theses experiments. It revealed that the model’s prediction closely matched the experimental data. At the 2023 Migration conference, results for the same glass were presented, highlighting the ability to take into account variations in the solution composition and in the glass surface-to-volume ratio therefore confirming that the model was perfectly able to predict these kinds of effects.This year, after a short presentation of the model, a 25-year experiment on the same simple glass is modelled to discuss the model’s ability to predict long-term experimental results. Initially the parameters determined from last year’s experiments are used. Some discrepancies with the experiment are discussed. Then a new set of optimized parameters is proposed to drive the discussion relative to the mechanisms at work over the course of such a long experiment. To conclude, the model’s capacity, parameterization method, and results are discussed to evaluate the overall model’s performance.[1] Zanini, R., Franceschin, G., Cattaruzza, E. et al. A review of glass corrosion: the unique contribution of studying ancient glass to validate glass alteration models. npj Mater Degrad 7, 38 (2023). https://doi.org/10.1038/s41529-023-00355-4[2] Frugier, P., Minet, Y., Rajmohan, N. et al (2018). Modeling glass corrosion with GRAAL. npjMater Degrad 2, 35[3] DELCROIX, Maxime. Modelling method for glass alteration with graal2 model. In : Goldschmidt 2023 Conference. GOLDSCHMIDT, 2023
Long-term geochemical modeling with graal 2
No full textInternational audiencePresented at the 2023 Goldschmidt conference, the GRAAL 2 model has been incorporated into the CHESS/HYTEC reactive transport code to predict the alteration of glasses used for radioactive wastes confinement [1] under geochemical disposal conditions [2]. GRAAL 2 takes into account hydrolysis, Interdiffusion, protective gel formation, secondary phases precipitation leveraging geochemical databases and reactive transport in the environment through Hytec. During the last Goldschmidt conference, the methodology for parametrizing the model and the result that can be obtained were presented. This was demonstrated through an application on two experiments performed on a simple glass of 4 oxides (SiO2 – B2O3 – Na2O – Al2O3) at 90°C in pure water [3]. An uncertainty study qualified the method and the results of the model on theses experiments. It revealed that the model’s prediction closely matched the experimental data. At the 2023 Migration conference, results for the same glass were presented, highlighting the ability to take into account variations in the solution composition and in the glass surface-to-volume ratio therefore confirming that the model was perfectly able to predict these kinds of effects.This year, after a short presentation of the model, a 25-year experiment on the same simple glass is modelled to discuss the model’s ability to predict long-term experimental results. Initially the parameters determined from last year’s experiments are used. Some discrepancies with the experiment are discussed. Then a new set of optimized parameters is proposed to drive the discussion relative to the mechanisms at work over the course of such a long experiment. To conclude, the model’s capacity, parameterization method, and results are discussed to evaluate the overall model’s performance.[1] Zanini, R., Franceschin, G., Cattaruzza, E. et al. A review of glass corrosion: the unique contribution of studying ancient glass to validate glass alteration models. npj Mater Degrad 7, 38 (2023). https://doi.org/10.1038/s41529-023-00355-4[2] Frugier, P., Minet, Y., Rajmohan, N. et al (2018). Modeling glass corrosion with GRAAL. npjMater Degrad 2, 35[3] DELCROIX, Maxime. Modelling method for glass alteration with graal2 model. In : Goldschmidt 2023 Conference. GOLDSCHMIDT, 2023
Long-term geochemical modeling with graal 2
No full textInternational audiencePresented at the 2023 Goldschmidt conference, the GRAAL 2 model has been incorporated into the CHESS/HYTEC reactive transport code to predict the alteration of glasses used for radioactive wastes confinement [1] under geochemical disposal conditions [2]. GRAAL 2 takes into account hydrolysis, Interdiffusion, protective gel formation, secondary phases precipitation leveraging geochemical databases and reactive transport in the environment through Hytec. During the last Goldschmidt conference, the methodology for parametrizing the model and the result that can be obtained were presented. This was demonstrated through an application on two experiments performed on a simple glass of 4 oxides (SiO2 – B2O3 – Na2O – Al2O3) at 90°C in pure water [3]. An uncertainty study qualified the method and the results of the model on theses experiments. It revealed that the model’s prediction closely matched the experimental data. At the 2023 Migration conference, results for the same glass were presented, highlighting the ability to take into account variations in the solution composition and in the glass surface-to-volume ratio therefore confirming that the model was perfectly able to predict these kinds of effects.This year, after a short presentation of the model, a 25-year experiment on the same simple glass is modelled to discuss the model’s ability to predict long-term experimental results. Initially the parameters determined from last year’s experiments are used. Some discrepancies with the experiment are discussed. Then a new set of optimized parameters is proposed to drive the discussion relative to the mechanisms at work over the course of such a long experiment. To conclude, the model’s capacity, parameterization method, and results are discussed to evaluate the overall model’s performance.[1] Zanini, R., Franceschin, G., Cattaruzza, E. et al. A review of glass corrosion: the unique contribution of studying ancient glass to validate glass alteration models. npj Mater Degrad 7, 38 (2023). https://doi.org/10.1038/s41529-023-00355-4[2] Frugier, P., Minet, Y., Rajmohan, N. et al (2018). Modeling glass corrosion with GRAAL. npjMater Degrad 2, 35[3] DELCROIX, Maxime. Modelling method for glass alteration with graal2 model. In : Goldschmidt 2023 Conference. GOLDSCHMIDT, 2023
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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