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Item High dynamic range and low power electrochemical analog front end(2025) Sukumaran, Amrith; Caruso, Francesco; Cattenoz, Régis; Putter, Bas; Nagel, Jean-Luc; Emery, Stéphane; Manic, DraganTechnology: GlobalFoundries 22nm FD-SOI 22FDX Die Size: 1mm x 1mm Design Tools: Cadence, Siemens Application Area: Medical / HealthItem Physics Informed Graph Neural Networks for Multi-Site Solar Forecasting(2024-09) Simeunovic, Jelena; Schubnel, Baptiste; Alet, Pierre-Jean; Carrillo, RafaelAccurate forecasting of photovoltaic (PV) power generation is crucial for efficient electricity management and market trading. Traditional data-driven models, while providing state-of-the-art accuracy for short-term forecasts, often suffer from limited generalization when facing data that deviates from their training distribution. Additionally, these models typically produce smooth forecasts that fail to capture the intricate dynamics of cloud movements, crucial for predicting solar irradiance, a primary driver of PV output. To address these challenges, we introduced a physics-informed graph neural network (PING) model that estimates the particle velocities of the historical input data, in an unsupervised fashion, and forecasts the future particle concentration values of advection-diffusion processes. In this paper we propose the combination of PING with our previously developed model, the Graph Convolutional Long-short term memory (GCLSTM) network, for multi-site PV power forecasting tasks. Numerical results showed that PING + GCLSTM outperforms all benchmarks on the entire horizon showing a daytime normalized root-mean-square error, overall sites, between 7% and 13% for 15 minutes and 6 hours ahead prediction, respectively.Item PEGDA-based HistoBrick for increasing throughput of cryosectioning and immunohistochemistry in organoid and small tissue studies.(2025-01-02) Vuille-Dit-Bille, Emilie; Utz, Larissa; Müllner, Fiona E; Arteaga-Moreta, Valeria J; Hou, Yanyan; Spirig, Stefan E; Ledroit-Paic, Diane; Heub, Sarah; Goldowsky, Jonas; Weder, Gilles; Renner, MagdalenaHistology is the gold standard for analyzing tissue structure and cell morphology. Immunostaining on thin tissue sections enables precise visualization of antigens and proteins. However, for cryosectioning small tissues such as organoids, spheroids, and tumoroids there is a lack of standardized, time- and cost-effective methods, limiting the throughput of analysis. Here, we have adapted to cryosectioning our previously developed HistoBrick approach, in which small tissue arrangement is spatially controlled within arrayed mini-wells. By testing various embedding matrices, we show that an 8% PEGDA and 2.5% gelatine mixture is optimal, providing essential structural support to maintain sample integrity during cryosectioning. This embedding matrix preserves fragile substructures of human retinal organoids, which are particularly susceptible to damage during sample preparation. Using PEGDA-gelatine HistoBricks for the simultaneous embedding of 16 retinal organoids, we analyzed a time course of retinal organoid development. We observed the maintenance of photoreceptors cell bodies up to week 98 in culture, while photoreceptor outer segments were gradually lost. Further, we observed displaced photoreceptors in the region of outer segments. The PEGDA-gelatine HistoBrick is a cost-efficient tool that can be implemented for small tissue studies to increase throughput in experiments such as large-scale screenings or toxicology research.Item In-situ fabrication of Ti-TiCx metal matrix composite by laser powder bed fusion with enhanced elastic modulus and superior ductility(2024-11-27) Bernard, Gaëtan; Pejchal, Vaclav; Sereda, Olha; Logé, Roland E.The production of high stiffness Ti-based Metal Matrix Composites (Ti-MMCs) displaying significant ductility is extremely challenging due to the high reinforcement content required. This study outlines the production process of stiffness-driven Ti-TiC MMCs displaying a remarkable ductility. The process consists in powder Mechanical Blending, Laser Powder Bed Fusion (LPBF), and a heat treatment. A TiC fraction of more than 20 vol% was formed in-situ through the reaction of titanium with carbon during the LPBF process. The as-built sub-stoichiometric TiC dendrites are converted in equiaxed TiC grains during the heat treatment. The TiC C/Ti ratio was found to be close to 0.5 in as-built conditions, and 0.7 in heat treated conditions, resulting in an effective reinforcement content nearly twice the one expected for stoichiometric TiC, leading to stronger reinforcement. The mechanical analysis revealed a Young’s modulus of up to 149 GPa and total elongations of up to 2.8 %. The former represents a 27 % improvement compared to commercially pure Titanium and the latter exceeds by 115 % reported values for LPBF Ti-MMCs with similar Young’s modulus. It is enabled by the in-situ formation of defect-free TiC reinforcements during the LPBF process combined with their globularisation through heat treatment.Item Tensile Properties of Ex-Situ Ti-TiC Metal Matrix Composites Manufactured by Laser Powder Bed Fusion(2024-11-17) Bernard, Gaëtan; Pejchal, Vaclav; Sereda, Olha; Logé, Roland E.Titanium-based Metal Matrix Composites (MMCs) manufactured by additive manufacturing offer tremendous lightweighting opportunities. However, processing the high reinforcement contents needed to substantially improve elastic modulus while conserving significant ductility remains a challenge. Ti-TiC MMCs fabricated in this study reported fracture strains in tension up to 1.7% for a Young’s modulus of 149 GPa. This fracture strain is 30% higher than the previously reported values for Ti-based MMCs produced by Laser Powder Bed Fusion (LPBF) displaying similar Young’s moduli. The heat treatment used after the LPBF process leads to the doubling of the fracture strain thanks to the conversion of TiCx dendrites into equiaxed TiCx grains. The as-built microstructure shows both un-dissolved TiC particles and sub-stoichiometric TiC dendrites resulting from the partial dissolution of TiC particles. The reduction of the C/Ti ratio in TiC during the process results in an increase in the reinforcement content, from a nominal 12 vol% to an effective 21.5 vol%. The variation of the TiC lattice constant with its stoichiometry is measured, and an empirical expression is proposed for its effect on TiC’s Young’s modulus. The lower TiC powder size distribution displayed higher mechanical properties thanks to a reduced number of intrinsic flaws.