Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

PhD : selection by topics

Sciences pour l'ingénieur >> Chimie physique et électrochimie
3 proposition(s).

Development of an analytical tool for ovulation detection dedicated to the improvment of the reproduction process in cattle breeding

Département Microtechnologies pour la Biologie et la Santé (LETI)

Laboratoire Chimie des Matériaux et des Interfaces

01-02-2018

SL-DRT-18-0558

pascal.mailley@cea.fr

This thesis is embedded within a larger aim collaborative project, SmartRepro (CEA-INRA) aiming at developing an automatic estrus detection tool that clearly differs from existing methods. The idea here is to get closer to the reference method of ovulation detection used in experimentation, namely the dosage of reproductive hormones. The originality of the project is to develop an on-board device containing a biological fluid sampling system capable of realizing these assays in real time and generating an alert to the farmer a few hours before the occurrence of ovulation. The aim of the thesis focuses on the development of the subcutaneous sampling tool residing in a network of hollow microneedles connected to a microfluidic device activated by a fluid pump. The implantation of the network is considered for the duration of an ovarian cycle and therefore should remain effective over a period close to 1 month. For this, solutions to avoid all inflammatory phenomena, likely to lead to the encapsulation of microneedles, and biofouling will be developed in order to conduct animal testing. As a preamble to this technical development, the PhD student will participate in experiments with INRA partner to determine the area of application of the sensor. This thesis aims to prove the concept of microneedles for the collection of interstitial fluids on an ovarian cycle over a five stage development from microneedle design to animal testing. We are searching for a PD student having an engineering formation in physics and a good background in microfluidics. A complementary formation in biomedical engineering will be greatly appreciated. The candidate have to be capable to work in a multidisciplinary fields (microfluidic, medical devices, animal experimentation, biomaterials)

Fracture of porous ceramics: application to the mechanical reliability of Solid Oxide Cells during thermal cycling

Département Thermique Biomasse et Hydrogène (LITEN)

Laboratoire Production d'Hydrogène

01-10-2018

SL-DRT-18-0583

jerome.laurencin@cea.fr

Solid Oxide Fuel Cells (SOFC) and Solid Oxide Electrolysis Cells (SOEC) are promising electrochemical converters operating at high temperatures. Among several advantages, SOFCs and SOECs can reach a very high efficiency without the use of specific electro-catalyst. Thanks to their reversibility, the same device can be alternatively used in fuel cell and steam electrolysis modes. The SOFC/SOEC are made of ceramic materials and they consist in two porous electrodes separated by a dense electrolyte. In planar configuration, the cells are assembled with metallic interconnects to form a stack of high power density. Because of the mismatch in Thermal Expansion Coefficients (TEC) between all the stack components, the cell layers are subjected to significant internal stresses. During the accumulation of start and shutdown of the system, the thermomechanical loading can induce damage in the electrode which leads to a decrease the global system efficiency. The PhD thesis aims to evaluate the mechanical degradation of the SOC electrodes when the stack is submitted to an accumulation of starts and shutdowns of the system. In that objective, it is proposed to validate a local fracture criterion that will be used to compute the density of micro-cracks in the 3D network of the electrodes. The results will be used to estimate the impact of the thermal cycling on the SOC performances.

3D Structured PGM free catalyst for PEMFC

Département de l'Electricité et de l'Hydrogène pour les Transports (LITEN)

Laboratoire Composants Pemfc

01-09-2018

SL-DRT-18-0662

pierre-andre.jacques@cea.fr

Proton exchange membrane fuel cell (PEMFC) is a system of choice to feed electrical engine for transport application. Recent presentation of fuel cell electrical vehicles (FCEV) from major car manufacturer (Daimler, Toyota, Hyundai) shows the interest of the car industry for the technology. The principle of PEMFC is based on electrochemical reactions to produce electricity from hydrogen oxidation (HOR) and oxygen reduction (ORR) reactions. Those both reactions are catalyzed by platinum (Pt) nanoparticles to accelerate their kinetics making them compatible with the required power density by automotive application. The state of the art 100 kw gross power stacks require around 50 g Pt ; 80% of them are used at the cathode. Those platinum loading is a real brake to the widespread of the technology. For several decades, scientist have been working of the decrease of Pt loading. One of the most ?noble? way studied in literature is the use of non PGM (platinum group metal) catalyst at the cathode. The proposed thesis aims at exploring an innovative way to prepared PGM free catalyst for ORR. This way consist in producing carbon aerogel material doped with N and low cost transition metal. The student will explore different C and N precursors and metals (Fe, Mn, Cu) to prepare 3D structured aerogel materials. Depending on the experimental set up and the used operating conditions to prepare those materials different structures will be obtained

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