1,721,002 research outputs found
Transport d'hydrogène dans les tokamaks : Estimation de l'inventaire en tritium du divertor d'ITER et influence de l'exposition hélium
No full textFuture fusion reactors will use a mixed fuel of deuterium and tritium. As a radioactive isotope of hydrogen, tritium can represent a nuclear safety hazard and its inventory in the reactors materials must be controlled. In ITER, the tritium in-vessel safety limit is 700 g.The tritium inventory of the ITER divertor was numerically estimated with the FESTIM code, which was developed to simulate hydrogen transport in tungsten monoblocks. A parametric study was performed varying the exposure conditions (surface temperature and surface hydrogen concentration) and a behaviour law was extracted. This behaviour law provided a rapid way of estimating a monoblock inventory for a given exposure time and for given surface concentration and temperature. This behaviour law was then used and interfaced with output data from the edge-plasma code SOLPS-ITER in order to estimate the hydrogen inventory of the whole ITER divertor. Under conservative assumptions, the total hydrogen inventory (deuterium and tritium) was found to be well below the ITER tritium safety limit, reaching around 14 g after 25000 pulses of 400 s.To investigate the influence of helium exposure on these results, a helium bubble growth model was developed. The results of this helium growth model were in good agreement with published numerical results and experimental observations. A parametric study was performed to investigate the influence of exposure conditions on the bubbles density and size. To investigate the influence of helium bubbles on hydrogen transport, deuterium TDS experiments of tungsten pre-damaged with helium were then reproduced. The distribution of bubbles density and size was computed using this helium bubble growth model and the results were used in FESTIM simulations. It was found that exposing tungsten to helium could potentially reduce the hydrogen inventory by saturating defects, making it impossible for hydrogen to get trapped. Moreover, the effect of helium bubbles (creation of additional traps for hydrogen) is limited to the near surface region (small compared to the monoblock's scale).Les futurs réacteurs à fusion utiliseront un combustible formé d'un mélange de deutérium et de tritium. En tant qu'isotope radioactif de l'hydrogène, le tritium peut représenter un danger en terme de sûreté nucléaire et son inventaire dans les matériaux des réacteurs doit être contrôlé. Dans ITER, la limite de sécurité du tritium en cuve est de 700 g. L'inventaire de tritium du divertor d'ITER a été estimé numériquement avec le code FESTIM, qui a été développé pour simuler le transport de l'hydrogène dans des monoblocs de tungstène. Une étude paramétrique a été réalisée en faisant varier les conditions d'exposition (température de surface et concentration en hydrogène de surface) et une loi de comportement a été extraite. Cette loi de comportement a permis d'estimer rapidement un inventaire monobloc pour un temps d'exposition, une concentration et une température de surface données. Cette loi de comportement a ensuite été utilisée et interfacée avec les données de sortie du code à plasma de bord SOLPS-ITER afin d'estimer l'inventaire d'hydrogène de l'ensemble du divertor de ITER. En s'appuyant sur des hypothèses restrictives, l'inventaire total d'hydrogène (deutérium et tritium) s'est avéré bien inférieur à la limite de sécurité du tritium d'ITER, atteignant environ 14 g après 25 000 impulsions de 400 s. Pour étudier l'influence de l'exposition à l'hélium sur ces résultats, un modèle de croissance de bulles d'hélium a été développé. Les résultats de ce modèle de croissance de l'hélium étaient en bon accord avec les résultats numériques publiés et les observations expérimentales. Une étude paramétrique a été réalisée pour étudier l'influence des conditions d'exposition sur la densité et la taille des bulles. Pour étudier l'influence des bulles d'hélium sur le transport d'hydrogène, des expériences TDS de deutérium de tungstène pré-endommagé avec de l'hélium ont ensuite été reproduites. La distribution de la densité et de la taille des bulles a été calculée à l'aide de ce modèle de croissance des bulles d'hélium et les résultats ont été utilisés dans les simulations FESTIM. Il a été constaté que l'exposition du tungstène à l'hélium pouvait potentiellement réduire l'inventaire d'hydrogène en saturant les défauts, rendant impossible le piégeage de l'hydrogène. De plus, l'effet des bulles d'hélium (création de pièges supplémentaires pour l'hydrogène) est limité à la région proche de la surface (petite par rapport à l'échelle du monobloc)
FESTIM
No full text<p>After several years of development, it is finally time to release 1.0! </p>
<h2>What's Changed</h2>
<h3>New features</h3>
<ul>
<li>Simulation time milestones by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/568</li>
<li>Export to txt at all times and in steady state by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/555</li>
<li>Dissociation flux by @jhdark in https://github.com/RemDelaporteMathurin/FESTIM/pull/557</li>
</ul>
<h3>Fixes</h3>
<ul>
<li>Fix parrallel hanging behaviour by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/571</li>
<li>Error raised when invalid field for BC by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/550</li>
<li>Fix final time overshoot by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/556</li>
<li>Trap density xdmf fix by @jhdark in https://github.com/RemDelaporteMathurin/FESTIM/pull/564</li>
<li>Patch derived quantities not exported at final timestep when stepsize is small by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/567</li>
<li>Linear solver for post-process chemical potential by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/579</li>
<li>Fix tiny timestep bug by @gabriele-ferrero in https://github.com/RemDelaporteMathurin/FESTIM/pull/580</li>
<li>Fix dissociation BC for festim by @gabriele-ferrero in https://github.com/RemDelaporteMathurin/FESTIM/pull/581</li>
</ul>
<h3>Documentation</h3>
<ul>
<li>Mamba for docs compilation by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/548</li>
<li>Update README conda package installation by @jhdark in https://github.com/RemDelaporteMathurin/FESTIM/pull/545</li>
<li>Smaller README by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/549</li>
<li>added ImplantationFlux to docs by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/560</li>
<li>Better api reference documentation by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/552</li>
<li>Examples in documentations by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/554</li>
<li>Remove demos from repo by @jhdark in https://github.com/RemDelaporteMathurin/FESTIM/pull/558</li>
<li>Fixed suggest edit in documentation by @gabriele-ferrero in https://github.com/RemDelaporteMathurin/FESTIM/pull/572</li>
<li>Added Info on different version installation in the getting started file by @gabriele-ferrero in https://github.com/RemDelaporteMathurin/FESTIM/pull/574</li>
</ul>
<h3>Misc</h3>
<ul>
<li>Use literal rather than "is not" by @jhdark in https://github.com/RemDelaporteMathurin/FESTIM/pull/553</li>
<li>fixed badge for circle by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/575</li>
<li>Deprecations by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/578</li>
<li>GithubActions instead of CircleCI by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/590</li>
<li>Added parametric test for Flux BC initialise by @gabriele-ferrero in https://github.com/RemDelaporteMathurin/FESTIM/pull/588</li>
</ul>
<h2>New Contributors</h2>
<ul>
<li>@gabriele-ferrero made their first contribution in https://github.com/RemDelaporteMathurin/FESTIM/pull/572</li>
</ul>
<p><strong>Full Changelog</strong>: https://github.com/RemDelaporteMathurin/FESTIM/compare/v0.11.1...v1.0</p>If you use this software, please cite it as below
openmc-dagmc-wrapper. A Python package for performing standard neutronics simulations with OpenMC and DAGMC
No full textWhat's Changed
Fix 2D mesh resolution by @RemDelaporteMathurin in https://github.com/fusion-energy/openmc-dagmc-wrapper/pull/93
Removed unused imports by @RemDelaporteMathurin in https://github.com/fusion-energy/openmc-dagmc-wrapper/pull/92
Wrapping dagmc bounding box by @shimwell in https://github.com/fusion-energy/openmc-dagmc-wrapper/pull/95
Allow bounding box from geomentry.corners() by @shimwell in https://github.com/fusion-energy/openmc-dagmc-wrapper/pull/96
Full Changelog: https://github.com/fusion-energy/openmc-dagmc-wrapper/compare/v0.3.0...v0.3.1If you use this software, please cite it as below
FESTIM
No full textWhat's Changed
Formatting by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/543
Fixing bug where stepsize is almost zero by @RemDelaporteMathurin in https://github.com/RemDelaporteMathurin/FESTIM/pull/542
Full Changelog: https://github.com/RemDelaporteMathurin/FESTIM/compare/v0.11.0...v0.11.1If you use this software, please cite it as below
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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