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Adaptive resonant piezoelectric shunt using tunable inductance
No full textInternational audienceResonant piezoelectric shunts are highly eective for reducing vibrations of a structural natural mode. However, they require a fine tuning on the mechanical resonance to ensure that performances are optimal. This paper proposes a novel adaptive resonant piezoelectric shunt circuit and investigates its ability to adjust the value of the inductance. This circuit is thus used to vary the electrical frequency of the shunt and it proposes a robust strategy for vibration mitigation of a linear resonance. The principle involves incorporating a static converter controlled by a pulse-width modulation (PWM) circuit between the piezoelectric patch and the inductance. PWM is performed thanks to four-quadrant switches controlled by a duty ycle. It is demonstrated that the resonance frequency is linearly governed by the duty cycle, with a range extending from zero hertz to the resonance frequency of the initial circuit. After numerical validation of the proposed circuit, experimental validation is performed on an elastic structure where damping is optimized to reduce the amplitude of a linear resonance. In practice, a dead time is required to prevent short-circuiting the blocking capacitor, which limits the extending range to approximately 100 to 200 Hz. Additionally, variations in static gain and damping have been observed, with their causes yet to be identified
Protégés mais toujours nomades ? Les parcours résidentiels contraints des mineurs non accompagnés en protection de l’enfance
No full textInternational audienc
The Critical Raw Materials Act’s weak circularity approach and its impact on the EU’s strategicautonomy
No full textInternational audienceThis communication analyses how the European Union’s Critical Raw Materials Act (CRMA) shapes the circularity of metals within the broader framework of Open Strategic Autonomy. Mobilising an analytical lens that bridges circular economy scholarship and the political economy of geoeconomic instruments, itargues that the CRMA institutionalises a form of “weak circularity”, centred on recycling and the securing of material flows, while largely neglecting measures aimed at moderating metals demand. Drawing on a qualitative analysis of the legislative process — including stakeholder consultations, institutional and lobbying documents, and semi-structured interviews — the study identifies the institutional, economic and political barriers that hindered the integration of “strong circularity” principles within the CRMA. It then examines how this orientation affects the defensive and offensive dimensions of the EU’s Open Strategic Autonomy. The article thereby sheds light on the internal tensions that characterise the EU’s evolving geoeconomic strategy and highlights the structural limits of a governance framework built on compromises between geopolitical imperatives, market logics, and environmental ambitions
Monitoring Ethical Tensions Encountered When Using Digital Health Solutions: Implementation of an Ethicovigilance Platform
No full textInternational audienceDigital health is transforming healthcare by enhancing accessibility, efficiency, and personalized care. It facilitates telemedicine, provides clinicians with data-driven insights, and streamlines administrative processes to reduce costs and improve patient care. However, challenges persist, including privacy concerns, data security issues, and the risk of exacerbating inequalities. To address these challenges, France’s Digital Health Delegation (DNS) developed a Framework for Ethics in Digital Health (CENS), emphasizing principles such as accessibility, transparency, trustworthy AI, and sustainability. Despite this initiative, achieving consistent ethical compliance remains difficult. In response, the DNS launched the Ethicovigilance platform in late 2023, enabling users to report ethical concerns when using digital health solutions. By 2024, 27 reports were collected, with 11 fully investigated. Key issues included unauthorized access to health data, lack of transparency, and insufficient user autonomy. These cases highlight systemic vulnerabilities, such as data misuse and inequitable access. Promoting trust, transparency, inclusivity, and accountability, alongside clear stakeholder responsibilities, is essential to align digital health with ethical standards and improve patient outcomes
De la surveillance des évènements sportifs à la surveillance des jeux Olympiques et Paralympiques de Paris 2024 : la sécurité triomphante ?
No full textInternational audienceRevue à comité de lecture ; validé par les pair
Rencontre européenne sur la formation ecclésiale dans une perspective synodale - Déclaration finale
No full textInternational audienc
Esther : une histoire de courage et de providence
No full texthttps://www.rcf.fr/vie-spirituelle/raisons-desperanc
Dynamiques de la végétation, usages et conservation : entre modèles écologiques et choix de société
No full textLes organes sur puce veulent s'affranchir du modèle animal grâce à l'électronique
No full textFoie, cœur, poumon, rein, intestin… Les organes sur puce permettent de recréer certaines fonctions d'organes humains – attention, il ne s'agit pas d'organes complets ! – à partir de cellules cultivées dans un système microfluidique, parfois instrumenté de petits dispositifs électroniques (notamment des électrodes) pour mesurer les changements. Car l'objectif de ces technologies est de pouvoir tester des composés et molécules dans le but de développer plus rapidement des nouveaux traitements de médecine personnalisée