Résultats de recherche

Cet événement sera consacré aux progrès en matière d'alimentation, de nutrition et de santé dans le cadre d'un système allant de la ferme à la table. Des sessions plénières, des ateliers et des visites de centres de recherche et d’universités seront également organisés. Cet événement unique sera l'occasion :D'explorer des solutions durablesDe découvrir l'expertise scientifique de la Wallonie,D'accéder aux dernières recherches et innovations dans le secteur,D'échanger avec des experts internationaux et développer votre réseau,De collaborer à des projets concrets pour avoir un impact positif et durable.2 jours avec plus de 150 participants internationaux et entreprises belges. L'inscription est gratuite mais obligatoire.Plus d'infos, inscriptions et programme complet ICI ! 

Plusieurs chercheurs du Namur Institute of Structured Matter (NISM) ont récemment obtenu des financements du F.R.S – FNRS à la suite des appels dont les résultats ont été publiés en décembre 2024.  L’Institut NISM fédère les activités de recherche des départements de chimie et de physique de l’Université de Namur. 

Entrez dans l’univers fascinant de la Space Week Namur 2024 ! Préparez-vous à un voyage extraordinaire à travers les étoiles et les mystères de l’espace. Voici le programme de cette semaine cosmique : Expositions “Objectif étoiles” : Avec cette exposition d'astrophotographie, plongez dans un océan d’étoiles scintillantes et laissez vous émerveiller par les secrets de notre galaxie. “Stellar Scape” :  Une aventure immersive où l'art et les sciences vous transporteront au cœur des paysages stellaires, où chaque étoile raconte une histoire. Événements "Mission ISS : Improvisation Space Station" :  Un spectacle de l’ImproNam, le kot-à-projet namurois d’improvisation théâtrale."Rencontre des astronautes" : Une chance unique pour les jeunes explorateurs de rencontrer des héros de l’espace et d’écouter leurs récits d’aventures au-delà de notre monde. “Mercredi des Savoirs” : Des ateliers interactifs pour les jeunes esprits curieux, prêts à découvrir les merveilles de la science.“Chill & Sciences” : Un moment convivial pour discuter avec un chercheur et un artiste, et explorer les mystères de l’univers. "Premier contact - Arrival" : Un ciné-rencontre proposé par le Caméo et Le Pavillon. "5 ans de l'Observatoire astronomique Antoine Thomas"Visites Visite de l’Observatoire astronomique Antoine Thomas : Une expédition guidée pour percer les secrets de l’observation astronomique et contempler les merveilles du cosmos. Ne manquez pas cette opportunité de plonger dans un univers fantastique et de partager des moments inoubliables avec des passionnés de tous horizons. Rendez-vous à Namur du 7 au 12 octobre 2024 pour la Space Week ! 🚀✨  Cliquez ici pour télécharger le programme et pour vous inscrire aux activités

Jury Prof. Benoît CHAMPAGNE (UNamur), présidentProf. Carmela APRILE (UNamur), secrétaireProf. Eric GAIGNEAUX (UCLouvain)Prof. Sonia FIORILLI (Politecnico di Torino)Prof. Wouter MARCHAL (UHasselt) Abstract Heterogeneous acid catalysts became over the years essential to our modern industrial world. Among the possible forms of solid materials with acidic properties, porous silica-based structures embedding active single-sites showed highly promising catalytic activity for various reactions. The insertion of heteroelements inside the SiO2 network is known to introduce a combination of Brønsted and Lewis acid sites which depends on the nature of the element and influences the catalytic properties of the solid. The present thesis investigates the link between the Brønsted/Lewis acid balance introduced by different elements (Al, Ga, In, Ti, Zr, Hf) inserted or finely dispersed in/onto the structure of extra-small silica nanospheres and the catalytic performances of the solids for two distinct biomass derivatives valorization reactions (i.e. conversion of glycerol to solketal and of ethyl levulinate to γ-valerolactone).The optimizations of the syntheses were particularly focusing on the insertion of the element inside the SiO2 matrix to maximize the number of acid sites. In-depth characterizations were conducted on the different substituted nanospheres to probe their morphological, structural, and textural features. A special attention was dedicated to the characterization of the surface acidity. These results were put into perspective with the catalytic performances of the materials. At the end of the investigations, we were able to explain the difference in terms of catalytic activity between the different studied solids and identify the optimal acid properties for the targeted reactions. The stability and recyclability of the best working solids were also assessed, an acute tuning of reaction conditions enabled to reach significatively high conversions, and their performances were tested in challenging conditions (i.e. close to crude feedstock).The knowledge unveiled through these investigations will give precious insight to design new silica-based catalysts with the appropriate acidity for a wide variety of acid-catalyzed reactions.

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 !