Résultats de recherche

Jury Prof. Catherine MICHAUX (UNamur), PrésidenteProf. Yoann OLIVIER (UNamur), secrétaireProf. Piotr DE SILVA (Technical University of Denmark)Prof. Daniel ESCUDERO MASA (KULeuven)Prof. Benoît CHAMPAGNE (UNamur)Prof. Luc HENRARD (UNamur) Abstract Organic Light Emitting Diodes (OLEDs) are now a well-established technology in modern electronic devices, from flexible TV screens to lighting applications. Each time we use our smartphone, billions of tiny molecules are electrically stimulated to emit the colorful light reaching our eyes. The ability of these molecules to convert electricity into light is the core principle of an OLED, and understanding the mechanisms behind this process can help improve their performance.Recently, two new families of triangular-shaped organic molecular systems, known as Multi-Resonant (MR) and Inverted Singlet-Triplet (INVEST) compounds, have shown promising features for OLED applications.In my PhD research, I used computational chemistry to explore the quantum mechanical effects that define the peculiar features of these systems.The first part of my thesis focused on identifying the correct computational protocol to properly describe the energy and nature of the singlet and triplet excited states of the INVEST compounds, highlighting the importance of methods including double excitations.  With this information in our hands, we combined quantum chemistry and group theory to design new light-emitting INVEST compounds. Finally, we applied both static and dynamic approaches to describe the spin conversion processes in MR and INVEST systems, providing a comprehensive picture of their electronic and photophysical properties for next generation OLED applications.

Jury Prof. Xavier DE BOLLE (UNamur), présidentProf. Jean-Yves MATROULE (UNamur) secrétaireDr Karrera DJOKO (Durham University)Dr Soufian OUCHANE (Paris-Saclay University)Dr Rob VAN HOUDT (SCK-CEN) Abstract The copper tolerance of the free-living bacteria Caulobacter crescentus depends on its dimorphic cell cycle. The sessile stalked cell detoxifies and effluxes copper through the multicopper oxidase PcoA and the Cu transporter PcoB respectively, while the swarmer cell senses and swims away from Cu sources. The transcriptional landscape of both morphotypes upon copper excess further confirms this. Among the few genes upregulated in both stalked and swarmer cells under copper excess, the CCNA_00027-00028 operon encodes a TonB-dependent receptor (TbcT) and a 2-oxoglutarate/Fe2+-dependent oxygenase (OxcT), respectively. The deletion of these two genes specifically increases the sensitivity towards Cu in C. crescentus. Interestingly, using a bioinformatics approach, we observed that the tbcT and oxcT genes co-occur in at least 67 % of bacteria containing a tbcT gene, and 88 % of bacteria containing an oxcT gene. The TbcT-OxcT system is not involved in the transport of copper nor the detoxification of copper-induced oxidative stress. Previous studies in C. crescentus and for homologous proteins showed that TbcT seems to be involved in iron import via siderophores, even though C. crescentus does not appear to synthesize siderophores. The overexpression of the tbcT gene appears to enhance the import of iron. OxcT activity is important for copper tolerance, although its specific activity has not yet been deciphered. Based on our results, we demonstrated that proper iron import is crucial for complete Cu tolerance, with the intracellular iron preventing copper accumulation. Taken together, our results argue for a tight coupling between iron and copper homeostasis in the context of copper tolerance. 

Jury Prof. Nathalie BURNAY (UNamur), présidenteProf. Sabine HENRY (UNamur), secrétaireDr. Florence DE LONGUEVILLE (UNamur)Prof. Nathalie MONDAIN (Université d’Ottawa)Prof. Etienne PIGUET (Université de Neuchâtel)Prof. Sane TIDIANE (Université Assane Seck/Ziguinchor) Abstract Recent attention to environmental change has highlighted its impact on rural communities, particularly in Africa, where household-level adaptations play a crucial role in larger societal responses. Current research often overlooks these small-scale, everyday adaptations and how they evolve over time, limiting our understanding of rural communities' dynamic responses to environmental changes. This study focused on households living in rural West Africa, more specifically in the region of Saint-Louis in Senegal. To capture the complexity of the household adaptation journeys, the structured timeline mapping methodology was developed, which consists of completing timelines during interviews. Timelines were collected from 39 individuals in 17 households to explore how families perceive and adapt to environmental shifts. In addition, this research reflected on the added value and necessity of interviewing multiple household members to capture diverse lived experiences and ensure a comprehensive household-level perspective.Analysis of the data categorized the adaptation journeys into four typological groups reflecting different sensitivities and adaptive capacities: (1) diversified adjusters, (2) system maintainers, (3) environmental independence strivers, and (4) opportunity-driven adapters. All groups have differentiated responses to similar environmental changes, with differences in the temporality of the response, differences in the types of adaptations, and differences in the amount and diversity of adaptations. These differences result in resilience that evolves unevenly over time. Understanding these varied adaptation pathways lead to formulate policy recommendations aimed at improving adaptive capacity, resilience, and sustainable livelihoods.

Depuis son inauguration en 2019, l’observatoire astronomique de l’UNamur a déployé un programme pédagogique et de médiation scientifique ouvert à toutes et à tous, avec l’ambition de faire découvrir les sciences par le prisme de l’observation des merveilles du ciel. 5 ans plus tard, le pari est réussi ! La petite équipe qui anime les lieux multiplie les collaborations et les activités proposées aux étudiantes et aux étudiants, aux écoles et au grand public. Cet automne, l’Observatoire astronomique célébrera l’empreinte durable qu’il a construite dans les yeux et les cœurs de son public en fêtant son 5e anniversaire. Une occasion de rassembler la communauté qui s’est développée autour de ses projets passés, présents et futurs ! Au programme 11H-16H : Visites de l’observatoireUNamur – Faculté des sciences12H-18H : Possibilité de visiter de l’exposition Stellar ScapeLe Pavillon de la Citadelle de Namur18H30 : Séance académique et réceptionUNamur – Faculté des sciences (S01)Inscriptions demandées via billetweb :

This event will be the perfect opportunity not only to discover the latest advances in the field of biological macromolecules research, but also to share knowledge, collaborate, as well as to showcase the outstanding work of PhD students. PhD students are encouraged to submit an abstract for an oral presentation and/or poster. Five talks will be selected on the basis of received abstracts and added to the final programme. Prizes will be awarded for the best oral presentation and the best poster at the end of the event.  More info about abstract submission and registration on the website

Jury Prof. Nathalie BURNAY (UNamur), présidenteProf. Sabine HENRY (UNamur), secrétaireDr. Florence DE LONGUEVILLE (UNamur)Prof. Nathalie MONDAIN (Université d’Ottawa)Prof. Etienne PIGUET (Université de Neuchâtel)Prof. Sane TIDIANE (Université Assane Seck/Ziguinchor) Abstract Recent attention to environmental change has highlighted its impact on rural communities, particularly in Africa, where household-level adaptations play a crucial role in larger societal responses. Current research often overlooks these small-scale, everyday adaptations and how they evolve over time, limiting our understanding of rural communities' dynamic responses to environmental changes. This study focused on households living in rural West Africa, more specifically in the region of Saint-Louis in Senegal. To capture the complexity of the household adaptation journeys, the structured timeline mapping methodology was developed, which consists of completing timelines during interviews. Timelines were collected from 39 individuals in 17 households to explore how families perceive and adapt to environmental shifts. In addition, this research reflected on the added value and necessity of interviewing multiple household members to capture diverse lived experiences and ensure a comprehensive household-level perspective.Analysis of the data categorized the adaptation journeys into four typological groups reflecting different sensitivities and adaptive capacities: (1) diversified adjusters, (2) system maintainers, (3) environmental independence strivers, and (4) opportunity-driven adapters. All groups have differentiated responses to similar environmental changes, with differences in the temporality of the response, differences in the types of adaptations, and differences in the amount and diversity of adaptations. These differences result in resilience that evolves unevenly over time. Understanding these varied adaptation pathways lead to formulate policy recommendations aimed at improving adaptive capacity, resilience, and sustainable livelihoods.

Jury Prof. André FÜZFA (UNamur), présidentProf. Alexandre MAUROY (UNamur), secrétaireProf. Joseph WINKIN (UNamur)Prof. Raphaël JUNGERS (UCLouvain)Dr Milan KORDA (LAAS-CNRS, Toulouse)Prof. Igor MEZIC (University of California Santa Barbara) Abstract Switched systems became more and more interesting since they are conceptually closed to the description of real complex dynamics in which the state is not necessarily fixed in time but can abruptly change with the environment. In this context, not only a finite number of subsystems (said modes) are given to describe the possible state of the system, but also a switching (or commutation) law is assigned to indicate the active mode at each time.The stability theory of such systems is not intuitive since it is influenced by the commutation law, which plays a capital role.This dissertation investigates the uniform stability (i.e. stability under any commutation laws) and the switching stabilization (design of a stabilizing commutation law) problems of switched nonlinear systems.In the last decades, these problems have mainly been studied for switched linear systems and partially solved for the nonlinear case.The strategy exploited here is based on a successful tool today: the Koopman operator. This is a linear operator acting on an infinite-dimensional space of functions valued on the nonlinear system's state space. Roughly speaking, it allows one to transform a nonlinear finite-dimensional dynamics into a linear infinite-dimensional dynamics, from which one can deduce results for the original nonlinear system. More precisely, we utilize the Koopman operator framework to address switched nonlinear systems' uniform stability and stabilization problems.For the first problem, by using a Lie-algebraic solvability condition, we show that individual globally asymptotically stable nonlinear vector fields which admit a common Koopman finite-dimensional invariant subspace generate a uniformly globally asymptotically stable switched nonlinear system. In a broader context, we develop a general framework for studying the (uniform) stability of (switched) nonlinear systems on the polydisk or the hypercube. This systematic approach allows us to construct a common Lyapunov function that guarantee global uniform  asymptotic stability on the polydisk or the hypercube. We then apply this framework to derive systematic criteria for the global stability of nonlinear systems defined on the polydisk or the hypercube. Finally, for the second problem, we utilize the previously developed results to provide a  state-dependent switching stabilization strategy from  a systematic Lyapunov function of a convex combination of nonlinear vector fields.

JuryProf. Guillaume BERIONNI (UNamur), présidentProf. Zineb MEKHALIF (UNamur), secrétaireProf. Catherine MICHAUX (UNamur)Prof. Noureddine NASRALLAH (Université des Sciences et Technologies - Houari Boumediene)Prof. Nacira NAAR (Université des Sciences et Technologies - Houari Boumediene)RésuméThe increasing in global energy demand and environmental concerns related to traditional energy sources necessitate the exploration of sustainable alternatives. This thesis investigates the potential of thermoelectric (TE) energy conversion using conducting polymer-based composites. Traditional TE materials, while efficient, face challenges such as toxicity and limited availability. Conducting polymers offer a promising solution due to their flexibility, processability, and tunable properties. By forming composites with materials like carbon nanotubes (CNTs) and graphene, their TE performance can be significantly enhanced. Surface treatment and functionalization are crucial for optimizing these composites and improving their efficiency.The thesis reviews the principles of thermoelectricity, including the Seebeck and Peltier effects, and the limitations of traditional TE materials, setting the stage for investigating conducting polymers as alternatives.The research methodology involves synthesizing and characterizing conducting polymer-based composites, focusing on surface treatment and functionalization techniques to enhance TE performance. Various composites incorporating graphene, CNTs, and metal oxide nanoparticles (bismuth oxide or nickel oxide) are synthesized and evaluated for their TE properties. The influence of surface modifications on composite morphology, charge transport, and TE parameters is systematically studied.The findings reveal significant improvements in TE efficiency through surface treatment and composite formation. Functionalization of graphene and CNTs enhances their compatibility with polymer matrices, improving dispersion and interfacial bonding, leading to higher electrical conductivity, reduced thermal conductivity, and ultimately, greater TE efficiency. Incorporating metal oxide nanoparticles further enhances the power factor, demonstrating the potential of hybrid composites in TE applications.Bienvenue à tous et toutes !

Au programme Pendant toute la semaine, des cours universitaires seront en accès libre pour aider les élèves à franchir cette première étape d’exploration de l’enseignement supérieur.Ils pourront également rencontrer un conseiller pour faire le point sur leur choix d’études, obtenir des informations sur les programmes ou les services offerts aux étudiants.Un atelier d’orientation sera aussi proposé le mardi 22 octobre, de 13h30 à 16h, pour réfléchir au processus d’orientation, mieux appréhender le paysage de l’enseignement supérieur et définir les balises principales dans le processus de clarification de leur projet (de formation et professionnel). Plus d'informations sur les cours ouverts Contacts Info étudesRue de Bruxelles, 85 5000 Namur+32 (0)81 72 50 30info.etudes@unamur.be

Chers enseignants, Nous avons le plaisir de vous inviter à une expérience éducative unique à l’Observatoire Astronomique Antoine Thomas. Offrez à vos élèves l’opportunité de découvrir l’Observatoire Astronomique Antoine Thomas, un observatoire construit sur les lieux-mêmes où les pères jésuites avaient établi leur propre coupole d’observation, de formation et de recherche, au XIXe siècle. Situé dans le centre-ville de Namur, au cœur de l’université, notre observatoire est équipé d’instruments de pointe, pour l’observation nocturne, mais aussi diurne, avec l’un des plus grands télescopes solaires de Belgique. Une visite de l’observatoire permet de découvrir comment se pratique aujourd’hui l’astronomie et – si les conditions météorologiques le permettent – d’observations le soleil en toute sécurité. Planifiez votre visite dès aujourd’hui ! Pour organiser une visite scolaire, veuillez remplir le formulaire d’inscription disponible sur notre site web.  Infos pratiques :Visite guidée 1ère à 6ème secondaire 13h30 à 14h30 ou 15h00 à 16h00 Faculté de médecine • Place du Palais de Justice, Namur Gratuit • Sur inscription L'observatoire n'est pas accessible aux personnes à mobilité réduiteProchaines dates :10 décembre 202414 janvier 202511 février 2025 Inscription aux visites

Chers enseignants, Nous avons le plaisir de vous inviter à une expérience éducative unique à l’Observatoire Astronomique Antoine Thomas. Offrez à vos élèves l’opportunité de découvrir l’Observatoire Astronomique Antoine Thomas, un observatoire construit sur les lieux-mêmes où les pères jésuites avaient établi leur propre coupole d’observation, de formation et de recherche, au XIXe siècle. Situé dans le centre-ville de Namur, au cœur de l’université, notre observatoire est équipé d’instruments de pointe, pour l’observation nocturne, mais aussi diurne, avec l’un des plus grands télescopes solaires de Belgique. Une visite de l’observatoire permet de découvrir comment se pratique aujourd’hui l’astronomie et – si les conditions météorologiques le permettent – d’observations le soleil en toute sécurité. Planifiez votre visite dès aujourd’hui ! Pour organiser une visite scolaire, veuillez remplir le formulaire d’inscription disponible sur notre site web.  Infos pratiques :Visite guidée 1ère à 6ème secondaire 13h30 à 14h30 ou 15h00 à 16h00 Faculté de médecine • Place du Palais de Justice, Namur Gratuit • Sur inscription L'observatoire n'est pas accessible aux personnes à mobilité réduite Prochaines dates :14 janvier 202511 février 2025Cette activité est organisée avec le soutien de la Wallonie Recherche. Inscription aux visites

Chers enseignants, Nous avons le plaisir de vous inviter à une expérience éducative unique à l’Observatoire Astronomique Antoine Thomas. Offrez à vos élèves l’opportunité de découvrir l’Observatoire Astronomique Antoine Thomas, un observatoire construit sur les lieux-mêmes où les pères jésuites avaient établi leur propre coupole d’observation, de formation et de recherche, au XIXe siècle. Situé dans le centre-ville de Namur, au cœur de l’université, notre observatoire est équipé d’instruments de pointe, pour l’observation nocturne, mais aussi diurne, avec l’un des plus grands télescopes solaires de Belgique. Une visite de l’observatoire permet de découvrir comment se pratique aujourd’hui l’astronomie et – si les conditions météorologiques le permettent – d’observations le soleil en toute sécurité. Planifiez votre visite dès aujourd’hui ! Pour organiser une visite scolaire, veuillez remplir le formulaire d’inscription disponible sur notre site web.  Infos pratiques :Visite guidée 1ère à 6ème secondaire 13h30 à 14h30 ou 15h00 à 16h00 Faculté de médecine • Place du Palais de Justice, Namur Gratuit • Sur inscription L'observatoire n'est pas accessible aux personnes à mobilité réduiteProchaines dates :10 décembre 202414 janvier 202511 février 2025 Inscription aux visites