HAL Portal Univ Catholille
Not a member yet
19763 research outputs found
Sort by
Influence of using wood biomass fly ash as filler on the rheological and physical properties of cementitious pastes
No full textInternational audienc
Régine Le Jan, Amis ou ennemis ? Émotions, relations, identités au Moyen Âge, Paris, Seuil, « L’Univers historique », 2024, 528 p.
No full textInternational audienc
Diaconat. Un ministère en chantier
No full textInternational audienceDans plusieurs Églises chrétiennes, le diaconat fait partie des ministères confiés à hommes et parfois à des femmes. Le récent Synode sur la synodalité, conclu en octobre 2024, a montré que la question du diaconat est toujours en chantier dans le catholicisme, 60 ans après la décision de Vatican II de le rétablir comme ministère permanent. Avec l’appel lancé aux Églises à être plus « généreuses » dans l’appel au diaconat, c’est un grand nombre de questions théologiques et pastorales qui sont soulevées, et qui bénéficient dans ce livre de plusieurs éclairages à l’aide d’historiens et de théologien(ne)s de plusieurs Églises.En effet, ce livre collectif, rédigé par des spécialistes venu(e)s de France, d’Europe et d’Amérique latine, est le fruit de la première année de travail de Diakonos, groupe de recherche international, interdisciplinaire et œcuménique, au sein de la Faculté de théologie de l’Université catholique de Lille. Distribué en trois parties, il accorde une large place à l’histoire, en interrogeant les conditions de son rétablissement dans l’Église catholique après Vatican II. Il offre ensuite un panorama d’expériences venues d’autres contextes culturels et ecclésiaux, avant de proposer enfin quelques repères sur le plan théologique, en laissant ouvertes plusieurs questions essentielles, comme la contribution des femmes, la transmission inter-générationnelle et l’articulation entre les différents ministères, ordonnés ou institués
Long-term thermo-mechanical behaviour of an energy pile installed in clay: Field experiments and numerical simulations
No full textInternational audienceThis study investigates the long-term thermo-mechanical behaviour of an energy pile installed in clay using field experiments and numerical simulations, aiming both to understand its response under sustained mechanical loads and cyclic thermal loading, and to develop a novel numerical model that can provide practical guidance for the design of energy piles. Firstly, full-scale experiments were performed on energy piles (0.42 m in diameter and 12 m in length) subjected to constant axial loads combined with three or five cyclic thermal loads. One pile was loaded to 30 % of its bearing capacity, and another to 50 %. Under these constant axial loads, the piles were subjected to several thermal loading cycles. Mechanical loading was finally applied to these piles after thermal cycles. A third pile was only mechanically loaded until the pile’s bearing capacity was reached. Results for the pile temperature and axial strain, pile head displacement, and axial load are shown. Secondly, a numerical model was developed based on a one-dimensional nonlinear finite element approach to investigate the long-term thermomechanical behaviour. This model was validated against the experimental results. It was then used to simulate 30 thermal cycles, revealing that the irreversible settlement of the pile head increases with higher axial loads, and that the first thermal cycle induces the largest irreversible settlement
Bioaccessibilité des polluants organiques persistants du sol : enjeux, expérimentations et finalités
No full textInternational audienceLe projet BORG (Bioaccessibilité des polluants organiques) vise à améliorer l'évaluation de la biodisponibilité relative (BDR) des polluants organiques (PO) dans les sols contaminés en développant et en validant des essais de bioaccessibilité (BA). Peu d'essais in vitro sont actuellement corrélés aux mesures in vivo, compliquant l'évaluation des risques sanitaires pour l'interprétation de l'état des milieux (IEM) ou les plans de gestion. BORG se concentre sur les sols multi-contaminés par des hydrocarbures aromatiques polycycliques (HAP), des polychlorobiphényles (PCB), de la chlordécone (CLD) et des substances perfluoroalkylées (PFAS). Ces PO sont particulièrement préoccupants en raison de leur persistance dans l'environnement et de leurs effets potentiels sur la santé humaine. Ces sols sont sélectionnés selon leurs caractéristiques physico-chimiques et les résultats des essais de BA réalisés in vitro. Les sols avec les variations de BA les plus larges sont utilisés pour des corrélations avec des données in vivo, obtenues via un modèle porcelet. Le projet optimise également les protocoles de BA en intégrant les résultats dans les équations de risque pour une évaluation précise de l'exposition humaine. BORG développera un outil d'aide à la décision pour les gestionnaires et mènera des expérimentations pour évaluer les transferts de contaminants vers les plantes et les animaux, soutenant le concept One Health pour les sols contaminés par des PO
Broadband surface acoustic wave attenuation in metals using chirp compression and dispersive interdigital transducers
No full textInternational audienceThis study presents a non-destructive method for estimating surface acoustic wave attenuation, which is highly sensitive to microstructural features, especially at high frequencies. The method uses a single wideband dispersive interdigital transducer (IDT) that remotely emits acoustic waves at the sample's edge. Chirp compression of the temporal displacement response is achieved by correlating the excitation signal with the spatial configuration of the IDT's electrodes. This technique generates high-amplitude pulses with a sufficient signal-to-noise ratio, critical for enabling accurate attenuation estimation over a frequency range (15-70 MHz). Results from nickel and aluminum demonstrate the method's effectiveness for rapid material characterization.</div
Estimating Rhizosphere Priming in European Agricultural Soils
No full textInternational audienceThe rhizosphere priming effect (RPE) is a key process where the mineralization of soil organic carbon (SOC) by microorganisms is modified by the presence and activity of plant roots compared to SOC mineralization on bare soil, increasing carbon fluxes from soils to the atmosphere. However, its magnitude in agricultural systems remains uncertain. Moreover, since the RPE is not specifically accounted for in earth system models it is a source of uncertainty in global carbon loss estimates relevant to achieve climate change targets. The PrimeSCale model offers a simple framework to quantify RPE-induced SOC respiration at large spatial scales. Here we aim to estimate the RPE in specific European croplands.The PrimeSCale model estimates the RPE using root carbon input to the soil derived from the combination of MODIS gross primary production (GPP) and net primary production (NPP) data, root depth distribution, heterotrophic respiration, soil bulk density and soil organic carbon content. A central component of PrimeSCale is the RPE ratio, the relative increase in heterotrophic respiration induced by priming based on literature using living plants. Our analysis of the time period 2010-2020 covers six types of croplands (maize, wheat, oat, barley, legumes, and soy) across Europe at a 5 km resolution, down to a depth of 200 cm. The model outputs include the magnitude of the RPE ratio and RPE-induced SOC loss in these croplands and how they vary within Europe according to climate and crops. Our findings will enhance understanding of the processes behind carbon cycling in managed environments and provide insights for carbon-farming policies to better suit mitigation strategies
Temperature-dependent electrostatic, linearity, and analog/RF performance of GaN HEMT
No full textInternational audienceTemperature has a major impact on the performance and reliability of high-frequency AlGaN/GaN HEMTs for high-power applications. Despite substantial research, these devices’ multi-bias behavior throughout a wide temperature range is still poorly understood. This study investigates DC, electrostatic, nonlinear, and analog/RF parameters from − 40 to 150 ℃ to fill this gap. The performance of GaN HEMT was evaluated by examining ON/OFF-state currents, subthreshold features, transconductance (gm), and its derivative, along with related parameters such as IMD3, 1-dB CP, and THD, which were evaluated together with RF performance indicators, including gain (Av) and gate-to-drain capacitance (Cgd). The transconductance generating factor (TGF), together with the product such as gain frequency (GFP), gain bandwidth (GBW), transconductance frequency (TFP), and gain transconductance frequency (GTFP), was also investigated. Among the electrostatic performance parameters, the currents in the ON state decreased, and the OFF state displayed an increasing trend as the temperature increased. The S-slope and S-swing, on the other hand, show a reverse trend with temperature. Both the current and the gm, along with its derivatives (gm2 and gm3), exhibit a declining trend as the temperature increases. The nonlinear performance of VIP2, VIP3, IIP3, 1-dB CP, IMD3, and THD, which rely on gm,is decreased with temperature. In terms of RF parameters, the Av, Cgd, ft, and fmax, as well as the TGF and GFP, are found to decrease with temperature. Meanwhile, the GBW, TFP, and GTFP all demonstrate an increasing trend with temperature. These findings provide valuable insights into the thermal impact on device parameters, which can be utilized to promote state-of-the-art technologies for the present and forthcoming deployments