Overview of SERMA’s Graphical User Interfaces for Lattice Transport Calculations

This article presents an overview of the graphical user interfaces (GUIs) developed at CEA/SERMA (Service d’Études des Réacteurs et de Mathématiques Appliquées) in Saclay, France, which have been used for over forty years by engineers and scientists to build geometries and meshes for general-purpose lattice transport calculations (neutrons and photons). Several applications make use of these calculations, from fuel assembly to full core design, criticality and safety, needing consistency check of the geometry and input properties before starting any lattice calculation. The software pattern design of the GUIs is briefly discussed, showing also the rationale behind the two interfaces for the construction of the geometries for simple fuel assemblies and complex motifs including the reflector (colorsets). The new GUI, ALAMOS, specifically developed for APOLLO3® with a Python Application Programming Interface (API), is here presented as the successor of Silène, which was the first GUI released in the 1990s to serve APOLLO2 calculations. The considerable experience gained by Silène over the years with plenty of various applications has provided a crucial support for the development of ALAMOS

Overview of SERMA’s Graphical User Interfaces for Lattice Transport Calculations

This article presents an overview of the graphical user interfaces (GUIs) developed at CEA/SERMA (Service d’Études des Réacteurs et de Mathématiques Appliquées) in Saclay, France, which have been used for over forty years by engineers and scientists to build geometries and meshes for general-purpose lattice transport calculations (neutrons and photons). Several applications make use of these calculations, from fuel assembly to full core design, criticality and safety, needing consistency check of the geometry and input properties before starting any lattice calculation. The software pattern design of the GUIs is briefly discussed, showing also the rationale behind the two interfaces for the construction of the geometries for simple fuel assemblies and complex motifs including the reflector (colorsets). The new GUI, ALAMOS, specifically developed for APOLLO3® with a Python Application Programming Interface (API), is here presented as the successor of Silène, which was the first GUI released in the 1990s to serve APOLLO2 calculations. The considerable experience gained by Silène over the years with plenty of various applications has provided a crucial support for the development of ALAMOS

High resolution irradiance tailoring using multiple freeform surfaces

More and more lighting applications require the design of dedicated optics to achieve a given radiant intensity or irradiance distribution. Freeform optics has the advantage of providing such a functionality with a compact design. It was previously demonstrated in [Bäuerle et al., Opt. Exp. 20, 14477-14485 (2012)] that the up-front computation of the light path through the optical system (ray mapping) provides a satisfactory approximation to the problem, and allows the design of multiple freeform surfaces in transmission or in reflection. This article presents one natural extension of this work by introducing an efficient optimization procedure based on the physics of the system. The procedure allows the design of multiple freeform surfaces and can render high resolution irradiance patterns, as demonstrated by several examples, in particular by a lens made of two freeform surfaces projecting a high resolution logo (530 × 160 pixels)

Balade : diffusion multicast sécurisée d'un flux multimédia multi-sources séquentielles dans un environnement ad hoc

2-7462-1151-3/http://www.hermes-science.com/fr/La sécurité des communications multipoint présente dans le cadre des réseaux ad hoc des nouveaux défis liés à la nature dynamique et flexible de ce type de réseaux. Nous présentons dans ce papier un nouveau protocole de gestion de clé de groupe dans le cadre des réseaux ad hoc. Ce protocole dénommé BALADE réalise une gestion de clé de groupe efficace, rapide et consciente de la mobilité pour un service de communications multicast, dans lequel les sources se succèdent de façon séquentielle (modèle 1 à n séquentiel). L'efficacité du modèle est validée par analyse et son applicabilité est démontrée au travers de sa mise en oeuvre dans un service de jukebox coopératif

Multiple intensity distributions from a single optical element

We report on an extension of the previously published two-step freeform optics tailoring algorithm using a Monge-Kantorovich mass transportation framework. The algorithm's ability to design multiple freeform surfaces allows for the inclusion of multiple distinct light paths and hence the implementation of multiple lighting functions in a single optical element. We demonstrate the procedure in the context of automotive lighting, in which a fog lamp and a daytime running lamp are integrated in a single optical element illuminated by two distinct groups of LEDs

Numerical modeling of a moderate hydrogen leakage in a typical two-vented fuel cell configuration

International audienceNumerical results are presented from two direct numerical simulations (DNS) where a moderate hydrogen leakage is modeled in a typical two-vented fuel cell configuration. The study mimics one of the experimental investigations carried out on the 1 m$^3$ enclosure with a leak flow rate of 10.4 Nl/min. The injection dimensionless Richardson number is at the order of unity and thus characterizes a plume flow which becomes turbulent due to gravitational accelerations. Two large exterior regions are added to the computational domain to model correctly the exchange between the in/out flows at both vents and the outer environment. Two meshes are used in this study; a first consisting of 250 million cells, while the second has 2 billion cells to ensure the fine DNS resolution at the level of Kolmogorov and Batchelor length scales. The high performance computation (HPC) platform TRUST is employed where the computational domain is distributed up to 5.10$^4$ central processing unit (CPU) cores. A detailed description of the flow structure and the hydrogen dispersion is provided where the sharp effect of the cross-flow on the plume is analyzed. Comparisons versus the experimental measurements show a very good agreement where both the bi-layer Linden regime and the maximal concentration in the top homogeneous layer are correctly reproduced by the DNS. This result is extremely important and breaks the limitations shown previously with statistical RANS approaches and LES models. This study can be considered as a good candidate for any further improvements of the theoretical industrial plume models in general, and for the estimation of the non-constant entrainment coefficient in particular