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Thermal Energy Storage (TES) systems are central elements of various types of power plants operated using renewable energy sources. Packed bed TES can be considered as a cost–effective solution in concentrated solar power plants (CSP). Such a device is made up of a tank filled with a granular bed through which heat-transfer fluid circulates. However, in such devices, the thermal stresses may accumulate from cycle to another due to differential thermal dilatation between filler and tank walls, leading to plastic deformations in the tank shell and the failure of the tank might happen. This paper aims at studying the evolution of tank wall stresses over granular bed thermal cycles, taking into account both thermal and mechanical loads, with a numerical model based on the discrete element method (DEM). Simulations were performed to study two different thermal configurations: (i) the tank is heated homogenously along its height or (ii) with a vertical gradient of temperature. Then, the resulting loading stresses applied on the tank are compared as well the response of the internal granular material.

Context. The identification of the sources that reionized the Universe and their specific contribution to this process are key missing pieces of our knowledge of the early Universe. Faint star-forming galaxies may be the main contributors to the ionizing photon budget during the epoch of reionization, but their escaping photons cannot be detected directly due to inter-galactic medium opacity. Hence, it is essential to characterize the properties of faint galaxies with significant Lyman continuum (LyC) photon leakage up to z ∼ 4 to define indirect indicators allowing analogs to be found at the highest redshift. Aims. Long gamma-ray bursts (LGRBs) typically explode in star-forming regions of faint, star-forming galaxies. Through LGRB afterglow spectroscopy it is possible to detect directly LyC photons. Our aim is to use LGRBs as tools to study LyC leakage from faint, star-forming galaxies at high redshift. Methods. Here we present the observations of LyC emission in the afterglow spectra of GRB 191004B at z = 3.5055, together with those of the other two previously known LyC-leaking LGRB host galaxies (GRB 050908 at z = 3.3467, and GRB 060607A at z = 3.0749), to determine their LyC escape fraction and compare their properties. Results. From the afterglow spectrum of GRB 191004B we determine a neutral hydrogen column density at the LGRB redshift of log(NH I/cm−2) = 17.2 ± 0.15, and negligible extinction (AV = 0.03 ± 0.02 mag). The only metal absorption lines detected are C IV and Si IV. In contrast to GRB 050908 and GRB 060607A, the host galaxy of GRB 191004B displays significant Lyman-alpha (Lyα) emission. From its Lyα emission and the non-detection of Balmer emission lines we constrain its star-formation rate (SFR) to 1 ≤ SFR ≤ 4.7 M⊙ yr−1. We fit the Lyα emission with a shell model and find parameters values consistent with the observed ones. The absolute (relative) LyC escape fractions we find for GRB 191004B, GRB 050908 and GRB 060607A are of 0.35−0.11+0.10 (0.43−0.13+0.12), 0.08−0.04+0.05 (0.08−0.04+0.05) and 0.20−0.05+0.05 (0.45−0.15+0.15), respectively. We compare the LyC escape fraction of LGRBs to the values of other LyC emitters found from the literature, showing that LGRB afterglows can be powerful tools to study LyC escape for faint high-redshift star-forming galaxies. Indeed we could push LyC leakage studies to much higher absolute magnitudes. The host galaxies of the three LGRBs presented here have all M1600 > −19.5 mag, with the GRB 060607A host at M1600 > −16 mag. LGRB hosts may therefore be particularly suitable for exploring the ionizing escape fraction in galaxies that are too faint or distant for conventional techniques. Furthermore, the time involved is minimal compared to galaxy studies. © J.-B. Vielfaure et al. 2020 This work is part of the BEaPro project (PI: S.D. Vergani) funded by the French Agence Nationale de la Recherche (ANR-16-CE31-0003). We thank Giancarlo Ghirlanda for providing useful information. JBV and SDV thank Anne Verhamme for useful discussions. SDV acknowledges financial support from the French Space Agency (CNES). MG was supported by NASA through the NASA Hubble Fellowship grant HST-HF2-51409 and acknowledges support from HST grants HST-GO-15643.017-A, HST-AR-15039.003-A, and XSEDE grant TG-AST180036. The Cosmic DAWN center is funded by the DNRF. JPUF thanks the Carlsberg foundation for support. DBM acknowledges support from VILLUM FONDEN research grant 19054. NRT acknowledges support from STFC via grant ST/N000757/1. DAK acknowledges support from Spanish research project RTI2018-098104-J-I00 (GRBPhot). The PanSTARRS1 Surveys (PS1) and the PS1 public science archive have been made possible through contributions by the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project O ffice, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, the Queen's University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation Grant No. AST-1238877, the University of Maryland, Eotvos Lorand University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium).Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. The NumPy (van der Walt et al. 2011), SciPy (Virtanen et al. 2020) and matplotlib (Hunter 2007) packages have been extensively used for the preparation and presentation of this work. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Peer reviewed

Nowadays, electrical energy is presented as the best alternative to be used in the non-propulsive aeronautic applications compared to hydraulic and pneumatic energies. The increase of embedded power in the aircraft causes the development of DC network over AC one, keeping the actual power transmission cables that will be subjected to new constraints. The anticipation of electric conductivity within the cable insulating system becomes essential in order to predict the electric field distribution and prevent any electric breakdown within insulating materials. This article presents experimental characterisation of PI (polyimide, Kapton-FN) and PTFE (polytetrafluoroethylene), two polymers used as insulators in the actual aeronautic cables. Current measurements are performed for different electric fields and temperatures, and the current behaviour is analysed with the help of a conductivity law. We then discuss the conductivity law and its optimized parameters.

Abstract In urban zones, vehicles are often subject to multiple starts and stops, due mainly to different traffic conditions which are highly energy consuming. This paper investigates the problem of optimal energy management in a Plug-in Hybrid Electric Bus (PHEB) in urban environment for the purpose of energy consumption minimization. Hereby an original control architecture is proposed which comprises an Adaptive Cruise Control with Stop&Go (ACCwSG) control system and stochastic energy management strategy. To this end, first, an ACCwSG maneuvers has been developed with the aim of maintaining an inter-vehicular distance that ensures safety, as well as providing passenger comfort by generating smooth velocity profiles. Secondly, a Stochastic Model Predictive Control (SMPC) has been developed to optimize PHEB power split. Power demand is addressed as a Markov Decision Process (MDP). To prove the efficiency of the proposed strategy, it is compared with a deterministic rule based method. The obtained results demonstrate the reduction of the energy consumption in average around 13%. The present work is conducted on a dedicated high-fidelity dynamical model of the hybrid bus that was developed on MATLAB/TruckMaker software.

Pipeline networks dominate the oil and gas mid-stream sector, and although the safest means of transportation for oil and gas products, they are susceptible to failures. These failures are due to manufacturing defects, environmental effects, material degradation, or third party interference through sabotage and vandalism. Internet of Things (IoT)-based solutions are promising to address these by monitoring and predicting failures. However, some challenges remain in the deployment of industrial IoT-based solutions, as the reliability, the robustness, the maintainability, the scalability, the energy consumption, etc. This paper is therefore aimed at highlighting potential solutions for detection and mitigation of pipeline failures while addressing the robustness, the cost and scalability issues of such approach efficiently across the network infrastructure, data and service layers. International audience

This paper considers the modeling energy consumption of a house with as objective the dimensioning and optimization of renewable energy sources and the energy saving. For the heating needs a house with 4 rooms is modeled and simulated in Matlab/simulink to predict the needed power. The thermal characteristic and model parameters are deduced for the architectural studies and design using architects softwares. We assume that 4 to 5 people live in this house of 100 m\(^{2}\). Despite the question seems classical, for going toward zero energy buildings, it has never been considered scientifically to define a complete set of models and simulations. In this work, we measured the consumption of each one of the house loads to be able to have a corresponding models. Detailed results can be available in an internal report and a PhD report .

L'épuisement progressif des matières premières d'origine fossile et la nécessité de réduire les émissions de gaz à effets de serre ont conduit la communauté scientifique à rechercher de nouveaux matériaux dont la production ne dépendra pas de ressources non renouvelables. Dans un autre temps ces matériaux pourront déjà être introduits sur le marché afin de substituer des produits déjà existant qui proviennent de matières premières fossiles. Par exemple, l'acide 2,5-furandicarboxylique (FDCA) obtenu par valorisation de la biomasse lignocellulosique est un potentiel substituant de l'acide téréphtalique actuellement utilisé pour la production de polyesters. En effet, le FDCA peut être obtenu par oxydation sélective du 5-hydroxyméthylfurfural (HMF) synthétisé à partir de la biomasse lignocellulosique. Ainsi, ce travail de thèse peut être défini par deux problématiques principales : (1) Le développement de catalyseurs pour l'oxydation de HMF en FDCA sans utiliser de bases inorganiques et (2) Développement de membranes catalytiques de polymères pour la future adaptation du procédé d'oxydation en réacteur à flux continu. Pour ce qui concerne l'oxydation de HMF dans des conditions neutres, une première étude s'est intéressée à la possibilité d'utiliser de l'oxyde de nickel nanométrique comme support pour des nanoparticules. Ensuite, la possibilité d'utiliser des nanoparticules de Pt supportées sur du TiO2 obtenues par décomposition contrôlée de clusters carbonyliques a été étudiée. Ainsi, des membranes de polymère obtenues par électrospinning, contenant les nanoparticules métalliques étudiées précédemment, ont été appliquées comme système catalytique pour l'oxydation du HMF The depletion of fossil-derived resources and the need to decrease the emission of green-house gases led scientists to look for sustainable materials to replace the already existing fossil-derived ones. For instance, 2,5-furandicarboxylic acid (FDCA) has been pointed out as the bioderived counterpart of terephthalic acid for the synthesis of polyesters. In fact, FDCA could be obtained by means of selective oxidation of 5-hydroxymethylfurfural (HMF), a bio-derived platform molecule produced by glucose hydrolysis. This reaction is known to be catalyzed by supported metal nanoparticle systems in presence of inorganic bases under batch conditions. This work deals with the development of catalytic systems able to perform the base-free HMF oxidation, since the possibility to circumvent base addition leads more sustainable processes. In particular, two different sets of catalytic systems have been studied: mono- and bimetallic Au and Pd nanoparticles on nano-sized NiO, and mono- and bimetallic Pt/Sn systems on titania, prepared via cluster precursor decomposition. Another topic that will be discussed in this thesis focuses on the development of catalytically active polymeric membranes obtained via electrospinning and their application as catalytic system for HMF oxidation either under basic and neutral aqueous conditions. In details, polyacrylonitrile and nylon have been tested as electrospun polymeric matrixes for the embedding of Au-based nanoparticles and Pt clusters