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Optimizing Antenna Impedance Adaptation for UHF RFID Design
No full textInternational audienceThis paper introduces comprehensive methodologies for optimizing UHF RFID performance over-the-air. The primary objective is to enhance the effectiveness of UHF RFID tags by maximizing the mean power transmission coefficient and modulation factor, crucial intrinsic characteristics. Through a systematic investigation within a predefined (M−−√,τ) , (Q, γ ) chart, we delve into these attributes, exploring their interplay. For a given chip, we establish and illustrate the valid domain, showcasing optimal antenna impedance choices. The culmination of this process is visually depicted by transforming the chart into the impedance plane, effectively highlighting antenna impedances that concurrently maximize both the mean power transmission coefficient and the modulation factor
Une abrogation subreptice : le licenciement des candidats à l’élection du CSE n’est plus soumis à l’avis du comité (CE avis, 16 mai 2025, n° 498924)
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Does development of submucosal dissection models influence quality of training? Comparison of existing models
No full textInternational audienceUse of endoscopic submucosal dissection (ESD) is growing, but access to it remains limited. The aim of this study was to compare the performance of various existing models and the progress made by students on them. Four training models (bovine colon (ex-vivo), ex vivo porcine model, live porcine model, and an artificial model (Endogel)) were evaluated during a 1-week training course. Each participant was evaluated at the beginning (D1) and at the end of the training (D5). Learners performed a standardized ESD of 2 cm on the four models in a randomized order. Experts evaluated the ability of participants to perform ESD using the objective structured assessment of technical skill score (OSATS). Sixteen students were involved, the average age was 35.6 years (+/- 4.6) and they practiced endoscopy for 10 years (+/-5.3). The OSATS significantly increased in each model during the week, with mean scores increasing from 8.6 to 23.3, from 10.7 to 12.9, from 8.8 to 21.3 and from 8.2 to 12.5 for the bovine colon, ex vivo porcine model, live porcine model, and Endogel models, respectively. Ex-vivo models are good models for learning ESD skills. The bovine colon model seems to be the most discriminating. Synthetic models should be reserved for novices
Climate change risks on key open marine and coastal mediterranean ecosystems
No full textInternational audienceMediterranean open marine and coastal ecosystems face multiple risks that impact their unique biodiversity, with climate change representing a major ongoing threat. While these ecosystems are also under pressure from non-climatic anthropogenic drivers (e.g., overfishing, pollution), this study primarily focuses on risks related to climate change. To assess these risks and evaluate their confidence levels, we adopt the scenario-based approach of the Intergovernmental Panel on Climate Change (IPCC), relying on a review of literature projecting changes in Mediterranean Sea ecosystems. The main drivers of environmental change are sea level rise, ocean warming and acidification. Similar to global conditions, all Mediterranean ecosystems face high risks under all climate scenarios, with coastal ecosystems being more strongly impacted than open marine ecosystems. For these coastal ecosystems, risk levels are expected to become very high already once global warming exceeds 0.8 °C with respect to the 1976–2005 period. A few Mediterranean ecosystems (e.g., coralligenous and rocky coasts) are relatively more resilient compared to others, probably because of their long evolutionary history and the presence of a variety of climatic and hydrological conditions. However, high-emission scenarios in specific sub-basins, in addition to acidification impacts, could reduce this resilience, decreasing both habitat extent and ecosystem function dramatically. Overall, due to the higher observed and projected rates of climate change in the Mediterranean, compared to global trends, for variables such as seawater temperature and pH, marine ecosystems (particularly coastal) are projected to be under higher risks compared to the global ocean
Défis Méthodologiques dans la Réalisation d’une Analyse de Cycle de Vie Simplifiée des Dispositifs Électroniques Denses : Le Cas des Smartphones
No full textInternational audienceEnvironmental Life Cycle Assessment (LCA) is becoming more widely adopted to evaluate the environmental impacts of devices and services across their manufacturing, use, and end-of-life phases. Life Cycle Assessments (LCAs) are usually conducted in several steps. After determining the goal and scope of the study, a first quick evaluation of impacts, called screening Life Cycle Assessment (LCA), aims at determining which activities and components significantly affect the impacts. Then, a cut-off method is applied that concentrates next LCA steps on activities and components representing more than a minimum share of impacts. Finally, a complete study is performed including precise life cycle inventory, measurements, impact assessment and interpretation. Screening LCAs are conducted in a few hours using generic environmental impact databases. The cut-off is a threshold that determines which components are considered in the final Life Cycle Assessment (LCA) based on their cumulative estimated impact (usually 3% of a total impact, e.g. carbon impact). The set of least impacting components below this cut-off are excluded, in order to streamline the analysis process.This paper concentrates on embodied carbon impacts of electronic devices, i.e. impact of manufacturing. This embodied carbon tends to dominate use and end-of-life phases in battery-powered devices. We demonstrate the difficulties of conducting a screening LCAs for assessing the impact of dense electronic systems such as smartphones and tablets, and propose a method for overcoming these difficulties. Indeed, the reliability of the cut-off method can be compromised by rough estimations and potential inaccuracies inherent to screening LCAs. We demonstrate on LCAs of the Apple iPhone 16 and Samsung Galaxy Note II Printed Circuit Board Assemblys (PCBAs) that screening LCAs tend to over-estimate and under-estimate different impacts, leading to the misidentification of significant components and to a flawed cut-off that cannot be corrected by subsequent steps. We propose a simple method to make more precise the screening Life Cycle Assessment (LCA) of an electronics system and show that this method significantly impacts the final results of the Life Cycle Assessment (LCA).L’analyse du cycle de vie environnementale (ACV) est de plus en plus utilisée pour évaluer les impacts environnementaux des dispositifs et services tout au long de leurs phases de fabrication, d’utilisation et de fin de vie. Les ACV sont généralement réalisées en plusieurs étapes. Après avoir défini l’objectif et le champ de l’étude, une première évaluation rapide des impacts, appelée ACV de présélection (ou screening ACV), vise à identifier les activités et composants ayant un impact significatif. Ensuite, une méthode de seuil (cut-off) est appliquée afin de concentrer les étapes suivantes de l’ACV sur les activités et composants représentant plus qu’une part minimale des impacts. Enfin, une étude complète est menée, incluant un inventaire détaillé du cycle de vie, des mesures, une évaluation des impacts et une interprétation.Les ACV de présélection sont réalisées en quelques heures à l’aide de bases de données génériques d’impacts environnementaux. Le seuil (cut-off) correspond à un pourcentage d’impact cumulé (généralement 3 % de l’impact total, par exemple l’impact carbone) à partir duquel les composants sont inclus dans l’ACV finale. Les composants dont l’impact est inférieur à ce seuil sont exclus, afin de simplifier le processus d’analyse.Cet article se concentre sur les impacts carbone incorporés des dispositifs électroniques, c’est-à-dire les impacts liés à la fabrication. Dans les dispositifs alimentés par batterie, ce carbone incorporé tend à dominer les phases d’utilisation et de fin de vie. Nous montrons les difficultés de réalisation d’ACV de présélection pour évaluer l’impact de systèmes électroniques denses tels que les smartphones et les tablettes, et proposons une méthode pour surmonter ces difficultés. En effet, la fiabilité de la méthode de seuil peut être compromise par les estimations approximatives et les inexactitudes inhérentes aux ACV de présélection.Nous montrons, à travers les ACV des assemblages de circuits imprimés (PCBAs) des Apple iPhone 16 et Samsung Galaxy Note II, que les ACV de présélection ont tendance à surestimer ou sous-estimer différents impacts, ce qui entraîne une mauvaise identification des composants significatifs et un seuil erroné, qui ne peut pas être corrigé par les étapes suivantes. Nous proposons une méthode simple pour rendre plus précise l’ACV de présélection d’un système électronique, et montrons que cette méthode a un impact significatif sur les résultats finaux de l’ACV
Hydrogen technology development: towards a revolutionary era in Europe?
No full textInternational audienceFollowing the synthesis of the European Commission's policy on renewable energies, this article details an overview of the current landscape of hydrogen in Europe as a game changer. The various challenges encountered in the hydrogen development regarding regulatory parameters, economic and technical issues are detailed. Hydrogen production processes are explained with a focus on the financial aspects. Current hydrogen end-users as an energy vector or as a chemical are described with a break-even price correlation with production. To promote the use of renewable hydrogen, decreasing its production cost is unavoidable. Additionally, this article highlights the importance of improving the energy efficiency of hydrogen uses in comparison to conventional fuel, particularly in the mobility sector. Considering the location of hydrogen end-users and producers, flexibility is essential in the electrical network, as well as in hydrogen transmission and storage infrastructures, to ensure the security of supply. As an illustration, this article discusses European projects that involve the conversion of natural gas networks, with a specific focus on the French case
Evaluation of archeo- and paleomagnetic field models and their common features
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Comparative Life Cycle Assessment of Inorganic and Organic PCM-Based Thermal Management in Photovoltaic Systems: A Case Study in Lebanon
No full textInternational audiencePV panel overheating reduces their performance, and through the incorporation of phase change materials (PCMs) in passive cooling, the temperature impact is being reduced. This paper performs a comparative life cycle analysis (LCA) of four PCMs, i.e., sodium sulfate decahydrate, sodium phosphate dodecahydrate, decanoic acid, and calcium chloride hexahydrate, used in a PV cooling module. A cradle-to-grave life cycle assessment is carried out, taking one PCM-based cooling system that regulates one PV panel over 20 years of lifespan in Lebanon as the functional unit. The ReCiPe 2016 approach to estimate climate change (kg CO CO2-eq), non-renewable energy (MJ), and water (m3) use was used. The results show that Sodium sulfate decahydrate yield the lowest impacts in the global warming potential, GWP (0.643 kg CO2-eq), while Sodium phosphate dodecahydrate yields the highest (2.13 kg CO2-eq, ∼ 3 × higher). Non-renewable energy demands and water usage were also compared. A study of uncertainty (1000-run Monte Carlo) confirms these rankings and discusses how differences in raw material availability and processing lead to these results and consider the implications for PV cooling in Lebanon. Overall, the readily available salt based PCMs (sodium sulfate and calcium chloride) offer a more sustainable cooling solution for PV panels, adding least carbon footprint to the PV panel among studied PCM but improving its performance. Conversely, bio-based organic PCMs carry higher burdens that may outweigh their benefits
An agent-based model to analyze the influence of IS integration and IS assimilation on the adoption dynamics of a green supply chain: The case of regional consolidation centers
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Enhancing photovoltaic panel efficiency through Water-Cooling: A parametric comparative evaluation of energetic, economic, and environmental benefits
No full textInternational audienceThe pressing need for more effective solar technology is highlighted by the global transition away from fossil fuels and toward renewable energy sources. Despite the enormous potential of photovoltaic (PV) panels, efficiency losses in high-temperature conditions limit their performance. The purpose of this study is to theoretically evaluate the energy, financial, and environmental advantages of different water-cooling techniques intended to improve the sustainability and operating efficiency of PV panels. In contrast to traditional research, this work quantifies increases in energy output, cost savings, and CO2 emission reductions across various cooling configurations by a thorough parametric analysis inside a single theoretical framework. To simulate how various water-cooling methods affect PV panel performance, a mathematical parametric model was created. Energy production, cost savings, and carbon footprint reduction were among the key performance metrics computed and compared for PV applications in relation to the consumption ratio R, which is defined as the ratio of the actual building load to the maximum PV power output, or the amount of energy consumed by the house from the PV panels. With an annual energy gain of 1354.10R kWh per panel, cost savings of 582.26R USD, and CO2 emission reductions of 785.37R kg, jet water impingement cooling (JWPV) outperformed the other technologies under evaluation. However, with energy gains of 1061.53R kWh, savings of 456.46R USD, and CO2 reductions of 615.68R kg, evaporative cooling (EPV) produced the least amount of improvement. These results highlight how important efficient cooling is to improving PV panel performance and developing sustainable solar energy solutions