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See detailFrom the Hubble Space Telescope to Juno, unraveling the secrets of Jupiter's UV aurorae
Bonfond, Bertrand ULg

Conference (2015, May 19)

The successive generations of instruments on board the Hubble Space Telescope (HST) have revealed an increasing amount of details concerning the aurorae of Jupiter. Among the most striking results is the ... [more ▼]

The successive generations of instruments on board the Hubble Space Telescope (HST) have revealed an increasing amount of details concerning the aurorae of Jupiter. Among the most striking results is the finding that these aurorae are actually made of a multitude of components arising from a variety of processes, ranging from the local interaction of the Jovian moons with the magnetospheric plasma to solar-wind induced compression of the whole magnetosphere. In this presentation, I will review a few recent results obtained from Hubble Space Telescope observations. First, I will show how the morphology and the dynamics of the Ganymede footprint, i.e. the aurora on Jupiter created by the electromagnetic interaction between Ganymede and Jupiter, allowed us to infer the processes at play. Then, I will present results on the vertical profile of the auroral emissions and what they tell us about the acceleration of the electrons causing the auroral emissions. Furthermore, I will describe some of the short-timescale dynamics of the polar-most emissions, including their quasi-periodic nature. Finally, I will conclude with a short description of the expected outcome of the Juno mission, which will provide its first scientific results in fall 2016. [less ▲]

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See detailThe influence of lithology on the mechanical strength and porosity of terra-cotta, the case study of Marrakech region (Morocco).
El Boudour El Idrissi, Hicham ULg; Daoudi, Lahcen; Collin, Frédéric ULg et al

Poster (2015, May 19)

The ceramic pastes in Marrakech region are prepared on the base of six types of raw materials of different lithologies. Various products are manufactured. The production consists of cooking utensils ... [more ▼]

The ceramic pastes in Marrakech region are prepared on the base of six types of raw materials of different lithologies. Various products are manufactured. The production consists of cooking utensils (based on schist, colluviums, quartzose sand and silt), decoration products (based on argillite, washing residues and soil), vases and gourds products (based on schist and soil), tiles (based on silt decantation) and traditional dishes (based on soil and argillite). In this study we elaborate bricks from the different raw material and we evaluate some of their physical properties after firing at 1050°C. In particular we measure the porosity to water and the mechanical strength of all the fired bricks. The aim is to compare the final product quality according to the origin (lithology) of the clayey raw material of the ceramic pastes. Based on our experiments, the bricks of the lower compressive strength (CS) and of the lower flexural strength (FS) are those based on sand (CS = 39 MPa; FS = 7 MPa), on silt decantation (CS = 25 to 39 MPa; FS = 10 to 18 MPa), and on schist and colluviums (CS = 20 to 51 MPa; FS = 6 to 17 MPa). Those of the highest values are based on argillites (CS = 33 to 102 MPa; FS = 13 to 28 MPa). The other pastes are characterized by intermediate values. The porosity ranges between 5 to 27%. The bricks based on silt decantation have the greatest values (20 to 27%), whereas those based on argillite have the lower values (5 to 10%). Those physical properties are, in most cases, in agreement with the requested values of the bricks industry. We conclude that such raw materials have high perspective to manufacture structural products of high performance in mechanical strength and thermal insulation. [less ▲]

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See detailEfficiency of pheromone-based formulations against phytophagous pests
Fassotte, Bérénice ULg; Vandereycken, Axel ULg; Chevalier Mendes Lopes, Thomas ULg et al

Conference (2015, May 19)

Innovative integrated pest management methods are needed to overcome market withdrawal of synthetic pesticides. Therefore, the identification of environment-friendly bio-products carrying direct or ... [more ▼]

Innovative integrated pest management methods are needed to overcome market withdrawal of synthetic pesticides. Therefore, the identification of environment-friendly bio-products carrying direct or indirect biocide activity is one promising alternative option. Our researches focus on the identification of appropriate formulations releasing volatile organic compounds that are attractant for natural enemies of insect pests. However, the elaboration of slow-release devices that ensure stable and controlled release of active volatile compounds is quite challenging. Here, we developed a formulation based on E-β-farnesene and (-)-β-caryophyllene, these two semiochemicals having strong attractive potential on aphid natural enemies including lady beetles and hoverflies. Both compounds were encapsulated together in alginate gel beads. The blend efficiency was first evaluated through laboratory assays, and then in wheat and broad bean fields, by considering the abundance and diversity of aphids and their natural enemies. [less ▲]

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See detailTuta absoluta (Lepidoptera: Gelechiidae) development on wild and cultivated plant species
Bawin, Thomas ULg; Dujeu, David ULg; Fagan, Maud ULg et al

Conference (2015, May 19)

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important cultivated solanaceous crop plants, including tomatoes and potatoes. Little ... [more ▼]

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important cultivated solanaceous crop plants, including tomatoes and potatoes. Little is known about the ability of this microlepidoptera to encounter and develop on alternative wild and agricultural plant species. These plants could provide refuges and have to be identified for more efficient integrated management strategies. In the present study, we assessed under laboratory conditions the ability of T. absoluta to develop on such plant species referred as potential hosts in the literature, including Solanaceae, Chenopodiaceae, Convolvulaceae, Fabaceae, and Malvaceae. For each plant species, fitness tests were performed in Petri dishes by isolating single individuals with excised leaf. We found that Solanum species allowed higher larval survivability and shorter development time (from egg to adult emergency) compared to the other plants. Non-solanaceous plants were not able to sustain T. absoluta larvae. Two choice behavioral assays performed in flying tunnels revealed that adult distribution and female oviposition did not differ between Solanum species, which were preferred to other tested solanaceous plants. These results appeared to be consistent with survival rates and development times. Because larval survivability depends on the female’s oviposition choice, the hypothesis that host plant choice is influenced by plant volatile organic compounds has to be tested. Volatile organic compounds released by solanaceous plants were trapped using a dynamic collection system, and analyzed by GC-MS. Solanum volatile profiles showed similarities, and were presenting quantitative and qualitative differences with the other tested solanaceous plants, providing some explanations in the observed behavioral discrimination. Further electrophysiological and behavioral assays are required to confirm the effect of specific chemicals on the choice of the oviposition site in T. absoluta. It can be concluded that Solanum species are the more suitable hosts for T. absoluta development. Other solanaceous plant species could be opportunistically colonized with little incidence but care should be taken in these results as genetic variability in insects and plants, as well as plant physiological state, might have an impact on the pest survivability. [less ▲]

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See detailComputer simulations of spray retention by a 3D barley plant: effect of formulation surface tension
Massinon, Mathieu ULg; De Cock, Nicolas ULg; Ouled Taleb Salah, Sofiene ULg et al

in 67th International Symposium on Crop Protection (2015, May 19)

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See detailDrop size distribution measurement of ISO nozzles by shadowgraphy method
De Cock, Nicolas ULg; Massinon, Mathieu ULg; Ouled Taleb Salah, Sofiene ULg et al

in Drop size distribution measurement of ISO nozzles by shadowgraphy method (2015, May 19)

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See detailDrift potential of tilted shielded rotary atomisers based on wind tunnel measurements
Ouled Taleb Salah, Sofiene ULg; Massinon, Mathieu ULg; De Cock, Nicolas ULg et al

in 67th International Symposium on Crop Protection (2015, May 19)

Detailed reference viewed: 17 (2 ULg)
Peer Reviewed
See detailApproche contingente du design du système d’information comptable dans les PMI tunisiennes
Ghorbel, Jihene ULg

Conference (2015, May 19)

Malgré les recherches qui sont de plus en plus nombreuses sur le système d’information comptable dans les PME, les résultats trouvés sont mitigés et contradictoires. Ainsi, nous essayons à travers ce ... [more ▼]

Malgré les recherches qui sont de plus en plus nombreuses sur le système d’information comptable dans les PME, les résultats trouvés sont mitigés et contradictoires. Ainsi, nous essayons à travers ce travail de contribuer au débat relatif du design du système d’information comptable dans les PMI des pays en voie de développement comme la Tunisie. Dans une optique comptable et face aux défis auxquels se trouvent confrontées les entreprises et pour légitimer leur compétitivité et leur crédibilité, nous nous intéressons à une série de facteurs structurels et comportementaux susceptibles de mieux cerner le design du système d’information comptable. En recourant aux méthodes des équations structurelles, cette recherche révèle que le design du système d’information comptable auprès de 221 PMI est influencé par plusieurs facteurs contextuels. [less ▲]

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See detailLe projet expérimental multidisciplinaire (PEMD) en 3ème Bachelier à Gembloux
Castillo-Bocanegra-Colaux, Catherine ULg; Pochet, Bernard ULg

Scientific conference (2015, May 18)

Cette courte présentation, dans l'atelier 3 du colloque ILIB15, décrit l'intégration d'un cours (« littérature scientifique et méthodologie documentaire »), dont le titulaire est un bibliothécaire, dans ... [more ▼]

Cette courte présentation, dans l'atelier 3 du colloque ILIB15, décrit l'intégration d'un cours (« littérature scientifique et méthodologie documentaire »), dont le titulaire est un bibliothécaire, dans une unité d’apprentissage intégrée basée sur la résolution d'un problème concret de recherche dans un contexte scientifique non familier. Ce cours a été proposé pour la première fois durant l'année académique 2014-2015 à une partie des étudiants du bloc trois du Master Bioingénieur, orientation Sciences et technologies de l’environnement de l'Université de Liège. Cette activité se déroule en plusieurs phases sur les deux quadrimestres. [less ▲]

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See detailRelever le défi des outils « discovery » : les formations orientées vers l’usager
Decoster, Sara ULg

Conference (2015, May 18)

Orientés vers l’usager, reprenant les habitudes de la génération « google », les outils « discovery » remettent en question le postulat que c’est à l’usager d’étudier la recherche documentaire. Les ... [more ▼]

Orientés vers l’usager, reprenant les habitudes de la génération « google », les outils « discovery » remettent en question le postulat que c’est à l’usager d’étudier la recherche documentaire. Les bibliothèques sont invitées à aller vers l’utilisateur et à se réinventer autour de la notion de « service ». Dans un monde informationnel où les enjeux sont de plus en plus complexes, le service à l’usager implique plus que jamais que la bibliothèque joue le rôle d’intermédiaire entre l’information et l’usager. Si l’usager doit rester maître de l’information, la formation aux compétences informationnelles reste à l’ordre du jour. Donnant cours à l’aide d’un outil « discovery », j’ai conclu qu’il est nécessaire de sortir du cadre très technique d’une recherche documentaire centrée sur la typologie documentaire et les équations de recherche. Ces éléments n’ont pas perdu leur pertinence, mais doivent être intégrés dans une structure basée sur les tâches et compétences de l’utilisateur, à savoir, la compréhension des possibilités et des limites des divers outils, l’interprétation des références et les phases de sélection, obtention et évaluation de l’information. Le but final sera toujours de permettre à l’usager de devenir acteur de l’information et de trouver sa propre position dans le paysage documentaire. Si les outils « discovery » nous amènent à faire le passage de la technicité à une approche par compétences, ils nous permettent de concevoir des formations véritablement orientées utilisateur. Tel est le défi que je voudrais relever en restructurant mes activités d’enseignement. [less ▲]

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See detailQuestion Intégrative - Médecine - Module Système Nerveux
Pasquet, Coralie ULg; Van de Poël, Jean-François ULg; Schaffer, Patrick ULg et al

Poster (2015, May 18)

Au cours du premier quadrimestre de l’année académique 2014 - 2015, une nouvelle activité a été proposée aux 270 étudiants inscrits en 3ième année du grade de Bachelier en Médecine à l’Université de Liège ... [more ▼]

Au cours du premier quadrimestre de l’année académique 2014 - 2015, une nouvelle activité a été proposée aux 270 étudiants inscrits en 3ième année du grade de Bachelier en Médecine à l’Université de Liège. Cette activité a été réalisée dans le cadre du « Module Système Nerveux ». [less ▲]

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See detailPrésentation de cas pratique - atelier n°2 « Outils et méthodes de formation : quels outils (EAD, MOOC, partage social, manuels...) et quelles méthodes (enseignement mixte, classe inversée, résolution de problèmes, travaux en groupe...) face à des groupes de tailles très variables ? Comment former avec peu de moyens (financiers, humains, matériels) ? »
Pasquet, Coralie ULg

Conference (2015, May 18)

Au cours du premier quadrimestre de l’année académique 2014 - 2015, une nouvelle activité a été proposée aux 280 étudiants inscrits en 3ième année du grade de Bachelier en Médecine à ... [more ▼]

Au cours du premier quadrimestre de l’année académique 2014 - 2015, une nouvelle activité a été proposée aux 280 étudiants inscrits en 3ième année du grade de Bachelier en Médecine à l’Université de Liège, ce dans le cadre du « Module Système Nerveux ». La réalisation progressive de cette activité s'est effectuée exclusivement en ligne. [less ▲]

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See detailDesign of new multifunctional nanocarriers for protein delivery
Parilti, Rahmet ULg; Jérôme, Christine ULg; Howdle, Steven M. et al

Conference (2015, May 18)

Polymeric nanoparticles have been extensively investigated for their biomedical applications especially as drug carriers. However, efficient encapsulation and delivery of therapeutic proteins in targeted ... [more ▼]

Polymeric nanoparticles have been extensively investigated for their biomedical applications especially as drug carriers. However, efficient encapsulation and delivery of therapeutic proteins in targeted manner still present challenges. This project aims to develop a novel one-pot strategy to obtain nanoparticles able to carry proteins in their core, as well as bearing targeting and/or imaging agents on their surface. In addition to this objective, polymerizations are carried out in supercritical carbon dioxide (scCO2), which confers environmentally benign features to the process. Dispersion polymerizations of hydrophilic monomer 2-hydroxyethyl methacrylate (HEMA) in are carried out in scCO2 in the presence of an initiator, cross-linker and CO2-philic photoclevable stabilizer. Upon exposure to UV light, the o-nitrobenzyl junctions present at the surface of the particles are cleaved, thus providing water dispersible hydrogels. Spherical monodisperse nanoparticles were successfully synthesized in scCO2 with two different conditions. Milder reaction conditions were achieved by using 2,2'-Azobis(4-methoxy-2,4-dimethyl valeronitrile (V70) as an initiator which opens up the platform for one-pot protein encapsulation in scCO2. [less ▲]

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See detailIntercalation of cationic aliphatic polyphosphates between montmorillonite nanosheets towards flame-retardant polymer materials
Carion, Stéphan ULg; Lecomte, Philippe ULg; Thomassin, Jean-Michel ULg et al

Poster (2015, May 18)

Among the strategies used to impart flame-retardant properties to polymer materials, the most effective ones include the addition of phosphorous compounds such as organic polyphosphates and the dispersion ... [more ▼]

Among the strategies used to impart flame-retardant properties to polymer materials, the most effective ones include the addition of phosphorous compounds such as organic polyphosphates and the dispersion of layered silicates (nanoclays). The aim of this work is to combine both approaches by the dispersion of nanoclays, organomodified by cationic aliphatic polyphosphates, into a polymer matrix. In this work, the synthesis of an aliphatic polyphosphate end-capped by an imidazolium cation followed by its intercalation between montmorillonite nanoclays sheets is reported. In a first step, the polyphosphate was synthesized by ring-opening polymerization of the corresponding cyclic phosphate using 1-(11-hydroxy-undecyl)-3-methylimidazolium bromide as initiator. This polymerization was catalyzed by DBU and a thiourea derivative. This polymer was characterized by different techniques (31P and 1H NMR, SEC, TGA, DSC). Finally, the cationic end-functionalized polymer was exchanged with sodium cations present in montmorillonite. The intercalation of the polyphosphate between the clay nanosheets was proved by X-Ray Diffraction (XRD) and thermogravimetric analysis (TGA). This last technique was also used to determine the influence of the intercalation on the thermal stability of the polyphosphate.polyphosphates, into a polymer matrix. In this work, the synthesis of an aliphatic polyphosphate end-capped by an imidazolium cation followed by its intercalation between montmorillonite nanoclays sheets is reported. In a first step, the polyphosphate was synthesized by ring-opening polymerization of the corresponding cyclic phosphate using 1-(11-hydroxy-undecyl)-3-methylimidazolium bromide as initiator. This polymerization was catalyzed by DBU and a thiourea derivative. This polymer was characterized by different techniques (31P and 1H NMR, SEC, TGA, DSC). Finally, the cationic end-functionalized polymer was exchanged with sodium cations present in montmorillonite. The intercalation of the polyphosphate between the clay nanosheets was proved by X-Ray Diffraction (XRD) and thermogravimetric analysis (TGA). This last technique was also used to determine the influence of the intercalation on the thermal stability of the polyphosphate. [less ▲]

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See detailNew efficient bicomponent organocatalysts for the chemical fixation of CO2 onto epoxides: a theoretical study
Alves, Margot ULg; Méreau, Raphaël; Grignard, Bruno ULg et al

Poster (2015, May 18)

Regarding the economic and environmental issues, valorising CO2 as a C1 feedstock for producing useful building blocks is seducing as it is a free and abundant waste resulting from the human activity ... [more ▼]

Regarding the economic and environmental issues, valorising CO2 as a C1 feedstock for producing useful building blocks is seducing as it is a free and abundant waste resulting from the human activity. Cyclic carbonates are useful compounds that found application as green solvents, electrolytes for lithium battery or monomers for polycarbonates or polyurethanes synthesis. These cyclocarbonates can be synthesized with a total atom economy by chemical fixation of CO2 onto epoxides using organometallic complexes or organocatalysts. To date, although this area of research has been the subject of many studies, the identification and development of (organo)catalysts highly efficient under mild experimental conditions still remains challenging. In this context, we developed a new organocatalytic platform based on the use of ammonium salts in combination with single or double hydrogen bond donor activators derived from fluorinated alcohols that showed unexpected booster effect. In this contribution, the ammonium/fluoroalcohol promoted CO2/propylene oxide coupling was investigated through detailed kinetic studies by IR spectroscopy under pressure and results were compared to the most efficient organocatalysts based on ammonium salts and (multi)phenolic derivatives that were reported in the literature. In order to finely understand the reaction mechanism, this study was completed by molecular modeling. DFT calculations showed that the addition of H-bond donors (HBD) with hexafluoroisopropanol functionalities modified the mechanism of the ammonium promoted coupling of CO2 with epoxides. HBDs dramatically decreased the epoxide ring-opening step barrier which highlights the key role of the fluorinated activators in stabilizing the intermediates and transitions states by inter- and intra-molecular hydrogen bonds. [less ▲]

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See detailNon-isocyanate polyurethane: from the monomer synthesis to foamed materials
Gennen, Sandro ULg; Alves, Margot ULg; Tassaing, Thierry et al

Poster (2015, May 18)

Polyurethane (PU) is one of the most important polymers in our everyday life with numerous applications such as thermosets, thermoplastics, elastomers, adhesives, sealants, coatings, rigid and flexible ... [more ▼]

Polyurethane (PU) is one of the most important polymers in our everyday life with numerous applications such as thermosets, thermoplastics, elastomers, adhesives, sealants, coatings, rigid and flexible foams... Classically, PUs are produced by a step-growth polymerization between diols and diisocyanates. However, isocyanates are harmful upon prolonged exposure to vapours which can lead to health issues such as asthma and skin irritation. In addition, isocyanates are produced from even more toxic and explosive phosgene. Due to these problems in combination with increasing regulatory scrutiny, there is today a need to develop isocyanate- and phosgene free- PU synthesis, also called non-isocyanate polyurethane or NIPUs. One of the most promising alternatives to the conventional synthesis of PU relies on the step-growth polymerization between bicyclic carbonate monomers and diamines, but until now, obtaining high molar mass NIPUs in a short time still remains a challenge. This study will be focused on three objectives: 1) The synthesis of CO2-sourced biscyclic carbonates by CO2/epoxide coupling using new highly efficient bicomponent organocatalysts allowing the fast conversion of epoxides into the corresponding cyclic carbonates under mild and solvent-free conditions. 2) The synthesis of high molar mass NIPUs from CO2-sourced monomers and diamines thanks to the use of efficient organocatalysts. A series of organic compounds interacting with cyclic carbonates by hydrogen bonding were first identified and their catalytic activity was highlighted by a model reaction between ethylene carbonate and a primary amine before extrapolation to NIPU synthesis. 3) The scCO2-assisted foaming of CO2-sourced NIPUs with production of potential carbon zero-emission materials with low thermal conductivity [less ▲]

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See detailAliphatic polyphosphates: a promising family of polymers for drug delivery
Vanslambrouck, Stéphanie ULg; Clément, Benoit; Riva, Raphaël ULg et al

Poster (2015, May 18)

Thanks to their biocompatibility and biodegradability, polyphosphates are appealing polymers for biomedical applications. In contrast to polyesters, polyphosphate properties and functionality are easily ... [more ▼]

Thanks to their biocompatibility and biodegradability, polyphosphates are appealing polymers for biomedical applications. In contrast to polyesters, polyphosphate properties and functionality are easily tuned via the chemical nature of the lateral chains. In this work, a series of amphiphilic PEO-block-polyphosphate copolymers were synthesized by organo-catalyzed ring-opening polymerization of cyclic phosphates. These polymers are directly dissolved in water in the absence of any organic solvent and they self-assemble to form nanoparticles Our work aims at changing the lateral chain of polyphosphates to investigate the influence of this structural modification on (i) the size of the nanoparticles, (ii) the critical aggregation concentration, (iii) the encapsulation of an hydrophobic drug in the core of the nanoparticles and, finally, (iv) the release of the drug. [less ▲]

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See detailPrerparation of graphene oxide-poly(methyl methacrylate) nanocompposites by a precipitation polymerization process and their dielectric and rheological characterization
Alkarmo, Walid ULg; Thomassin, Jean-Michel ULg; Macosko, Christopher et al

Poster (2015, May 18)

The graphene sheet, a flat monolayer composed of sp2-bonded carbon atoms packed into a two-dimensional honeycomb structure, has attracted a tremendous attention due to its extraordinary electrical ... [more ▼]

The graphene sheet, a flat monolayer composed of sp2-bonded carbon atoms packed into a two-dimensional honeycomb structure, has attracted a tremendous attention due to its extraordinary electrical, thermal, and mechanical properties. Graphene nanosheets–poly(methyl methacrylate) GN/PMMA nanocomposites were prepared via a precipitation polymerization process in a water/methanol mixture and thermal or chemical reduction of graphene oxide (GO). Scanning electron and transmission electron microscopies confirmed that the precipitate consists of polymer particles (<1μm) surrounded by the GO sheets. The GO sheets acts as a surfactant and adsorbs on the interface between polymerized PMMA particles and solvent mixture. Parallel dielectric and rheological characterization demonstrated that the thermal reduction is a quite fast process without significant degradation of the polymer. In addition, the main increase in electrical conductivity occurred during the first minutes of the thermal treatment but continued for about 30 min. The absence of dramatic change in the storage modulus confirmed that the increase in conductivity was not due to alteration of the particle dispersion. The addition of GO sheets had a dramatic influence on the glass transition (Tg) temperature of PMMA with an increase of 8 °C at only 0.2 wt %. This Tg increase has been attributed to the restricted mobility of PMMA chains which have been grafted onto the graphene surfaces during the in-situ polymerization. However, at GO content higher than 0.7 wt %, the glass transition decreases. This drop may be attributed to the increase in the number of stacked graphene layers. The obtained GN/PMMA composites not only have enhanced mechanical properties but also achieved electrical conductivity higher than 10 −2 S/m at 0.4 wt % of GO. The study should open up new opportunities in the design of GN-based polymer nanocomposites. [less ▲]

Detailed reference viewed: 59 (12 ULg)