Development of Monte-Carlo methods for the simulation of radiative transfer: application to severe accidents
This post-doctoral subject concerns the development of Monte-Carlo ray-tracing methods for modeling radiation heat transfer in the context of severe accidents. Starting from a well-developed software framework for Monte Carlo simulation of particle transport in the context of reactor physics and radiation protection, we will seek to adapt existing methods to the problem of radiative heat transfer, in a high-performance computing framework. To do this, we will develop a hierarchy of approximations associated with radiative heat transfer that are intended to allow the validation of simplified models implemented in the context of the numerical simulation of severe accidents in nuclear reactors. Focusing on algorithm and simulation performance, this work is intended to be a "proof of principle" of the possible software mutualization around the Monte-Carlo method for particle transport on the one hand and radiative heat transfer on the other hand.
New Sustainable Carbon Catalysts for PEMFC
The aim of the project is to develop and test for ORR, a mesoporous and graphitised graphene aerogel based material, presenting a hierarchical structuring allowing a better material transfer and graphitic domains increasing the durability and conductivity of the final material, and functionalised by Pt-NPs.
These graphene-based structures developed at IRIG/SyMMES possess surface chemistries and micro/meso/macro porosities that depend on the synthesis, functionalisation and drying methods used. The aim will be to increase their degree of graphitisation, and then to deposit Pt-NPs by chemical means. The electrocatalytic properties of these materials will then be tested.
Advanced meso-structural characterisation of these materials by scattering (X-ray or neutrons) methods will enable to investigate the structural properties of these new electro-catalysts. These properties will thenbe correlated to their electrocatalytic properties, and performances in fuel cell systems. This knowledge will be gained through ex-situ and operando analyses.
CIGS solar cells optimized for energy harvesting applications in indoor environments
The goal of this post-doctoral fellowship is to develop solar cells based on CIGS thin films, for energy harvesting applications (powering of small electronic autonomous devices). This research project will aim at optimizing the solar cell performances in indoor environments, i.e., under low light intensity. The post-doctoral fellow will be involved in CIGS thin film elaboration by physical vapour deposition, film characterization, solar cell realization and test.
Characterisation of vanadium alloys
Vanadium alloys, investigated in the scope of application in fusion reactors, are potential candidates for fuel cladding of future sodium cooled or gas cooled fasts reactors. Then, in 2009, CEA launched a program aiming to assess this solution according to future reactor requirements.
Preliminary investigation of V-4Cr-4Ti plates was done at DMN/SRMA/LA2M (i) on a reference Japanese grade and (ii) on a specific grade fabricated for CEA study. Works haw focuses on recrystallisation structure after cold working (grain size and morphology, effect of annealing temperature), and on fine microstructure (occurrence of Ti(O,C,N) precipitation). In 2011, fabrication of vanadium tube by hot extrusion is planned to be relevant of the final cladding geometry. The proposed post-doc investigation aims to monitor the fabrication and to specify the impact of fabrication process on microstructure, recrystallisation dynamic and mechanical properties.
Thermodynamic Modelling of Complex Oxides for Smart Sensors
The search for more efficient materials follows a pattern that has changed very little over the years, involving poorly automated phases of synthesis, characterization and measurement of functional properties. Although this pattern has proved its strength in creating knowledge bases, it remains ineffective because it is time-consuming and generally covers a reduced range of compositions. The project Hiway-2-mat (https://www.pepr-diadem.fr/projet/hiway-2-mat/) seeks to use high-throughput combinatorial approaches and develop autonomous configurations to explore the compositional spaces of complex oxide materials, with the aim of accelerating the discovery of materials for smart sensors. In this context, CALPHAD method is a valuable tool for materials exploration, as it can provide a number of useful insights into the role of oxidation state or oxygen partial pressure on phase stability, and on the degree of substitution of doping elements in an oxide matrix. The aim is to calculate phase diagrams of complex oxides based on available databases, either to better prepare combinatorial experiments, or to drive the autonomous robot on the fly, providing additional information for on-line characterization.
Your role will be to:
1)Perform thermodynamic simulations using CALPHAD method and Thermo-Calc Software to predict the stability range of a set of complex oxides (Ba/Ca/Sr)(Ti/Zr/Sn/Hf)O3 at different temperatures and oxygen partial pressures. In this step, the candidate will also perform a critical review of the thermodynamic data available in the literature.
2)Include key elements in the available database.
3)Develop a rapid screening method to search for the most promising compositions.
The candidate will work closely with the experimental platform development team to guide future trials and adapt the method to better meet the needs of large-scale production.