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See detailA review of Silurian dispersed spore assemblages from the Arabian Plate: biostratigraphy and palaeogeography
Wellman, CH; Steemans, Philippe ULg; Breuer, P et al

Conference (2016, October)

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See detailLes conséquences civiles des polices administratives sur la vente immobilière. Etude comparée des droits wallon, flamand et bruxellois
Onclin, François ULg

Doctoral thesis (2016)

On observe une influence grandissante des polices administratives sur le droit des contrats. La police administrative désigne l'ensemble des pouvoirs qui sont accordés, par ou en vertu d'une disposition ... [more ▼]

On observe une influence grandissante des polices administratives sur le droit des contrats. La police administrative désigne l'ensemble des pouvoirs qui sont accordés, par ou en vertu d'une disposition législative, aux autorités administratives et qui permettent de restreindre les droits et libertés des individus en vue d'assurer le maintien de l'ordre public. A côté de la police administrative générale qui tend à assurer le maintien de la sécurité, de la salubrité et de la tranquillité publiques, de nombreuses polices administratives spéciales se sont développées. Ces dernières visent à prévenir des troubles spécifiques, dont l'objet est défini par chaque législation particulière. Lors de la mise en œuvre de sa compétence, le législateur de police recourt à différents procédés. Il en résulte que de nombreuses contraintes de police encerclent les opérations contractuelles qui portent sur des biens immeubles. La recherche entreprise a toutefois limité son champ d’étude à la vente immobilière étant donné qu’il s’agit de l’acte de droit civil le plus fréquent et le plus souvent encadré par les polices administratives des biens. La législation de police renforce parfois la violation des exigences qu’elle impose d’une sanction administrative ou pénale. L’exercice se complique lorsqu’il s’agit d’apprécier les conséquences civiles des polices administratives. Dans ce cas, il convient à la fois de se référer à la théorie générale des obligations et à l’éventuelle sanction civile qui est aménagée par la législation de police. Tel est précisément l’objet de cette thèse, à savoir l’étude des conséquences, sur le plan civil, des polices administratives sur la vente immobilière. La thèse se structure en deux parties. La première a examiné la situation dans laquelle les polices administratives influencent la formation de la vente. La seconde avait, quant à elle, pour objet d’apprécier la mesure dans laquelle ces mêmes polices ont un impact sur les effets de la vente. Le système de répartition des compétences mis en place au sein du fédéralisme belge impose une recherche comparée. Celle-ci est entreprise en droit interne. De nombreuses polices administratives ont été, pour d’importantes parties, régionalisées. Elles ressortissent dès lors à la compétence du législateur régional. Pour cette raison, la recherche a été étendue aux droits wallon, flamand et bruxellois. Le droit des obligations et des contrats demeure, sous réserve de certaines exceptions, de la compétence de l’autorité fédérale. Lorsque la sanction civile est étudiée, il en résulte une tension entre, d’une part, la compétence du législateur fédéral et, d’autre part, celle du législateur de police. La rigidité de cette division des compétences engendre des difficultés. [less ▲]

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See detailUNESCO, Cultural Industries and the International Development Agenda: Between Modest Recognition and Reluctance
Vlassis, Antonios ULg

in Stupples, Polly; Teaiwa, Katerina (Eds.) Contemporary perspectives on Art and International Development (2016)

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See detailEtude des sémiochimiques volatils impliqués dans le mutualisme fourmis-pucerons
Fischer, Christophe ULg

Doctoral thesis (2016)

For decades, the mutualistic relationship that ant and aphids may present has fascinated entomologists, as evidenced by the abundant literature on the subject. The principles of this interaction are ... [more ▼]

For decades, the mutualistic relationship that ant and aphids may present has fascinated entomologists, as evidenced by the abundant literature on the subject. The principles of this interaction are simple: as long as their colony remains, aphids provide ants with a stable and abundant source of sugars, honeydew. In exchange, ants tend aphid colonies and provide them cleaning and protection against various natural enemies. Nevertheless, some aspects of this relationship remain misunderstood. This is for example the case of the factors influencing the search and the discovery of a potential partner, first step to any potential mutualistic interaction. The role held by volatile chemical cues, called semiochemicals, in this relationship is also misunderstood. The objective of this thesis is to improve understanding of the role played by volatile semiochemicals in this mutualistic relationship, especially during the partner search stage, both from the perspective of the ant and of the aphid. The black garden ant, Lasius niger L., and the black bean aphid, Aphis fabae Scop., constitute our biological model. The impact of volatile compounds on the search behavior of the ant has first been investigated. These compounds are from multiple origins, either directly emitted by the aphid or induced by its presence. First, the ability of ants to perceive E-β-farnesene, the main component of many aphid alarm pheromone, and to use it to locate aphid colonies has been highlighted. This compound has indeed shown attractiveness to ants, even at low doses corresponding to the emissions of an unstressed aphid colony. Then, the roles played by honeydew volatile compounds in ant attraction have been demonstrated. These compounds also allow ants to remotely discriminate different aphid species and to direct their searches accordingly. These semiochemicals are produced by honeydew microflora, and a particularly attractive bacterial strain, Staphylococcus xylosus, has been isolated from A. fabae honeydew. Finally, the active role of winged aphids, which are aphid’s dispersal form, in the search for a mutualistic partner was also studied. Aphids do not appear to be preferentially attracted toward a host plant frequented by ants or close an ant nest. Nevertheless, once a potential host plant reached, they remain longer on it in case of ant presence. This thesis highlights the importance of volatile semiochemicals and honeydew microflora in ant-aphid mutualistic relationships, thus completing by a new aspect an already well documented biological model. [less ▲]

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See detailMicroorganisms and semiochemicals to manipulate aphidophagous predators
Verheggen, François ULg

Conference (2016, August)

Semiochemicals provide a powerful way for organisms to communicate and coordinate their behaviors. But they also represent opportunities for other organisms to intercept and exploit such signals. There ... [more ▼]

Semiochemicals provide a powerful way for organisms to communicate and coordinate their behaviors. But they also represent opportunities for other organisms to intercept and exploit such signals. There are now numerous examples of natural enemies eavesdropping the intraspecific communication of their prey to better locate them. Aphid natural enemies, including predators and parasitoids, frequently exhibit innate responses to chemical cues reliably associated with aphids, and there is also abundant evidence that learning of profitable chemical cues frequently occurs. Thenceforth, the efficiency of aphid natural enemies to locate their prey is mainly based on their ability to perceive and orientate toward aphid-associated semiochemicals. Aphid predators were shown to respond to different groups of aphid-related semiochemicals, including aphid-induced plant volatiles; aphid pheromones and the more recently identified bacteria-produced honeydew volatiles. These laboratory studies suggest potentially promising avenues for the deployment of aphid-associated semiochemicals for the management of these pest species. While laboratory experiments are invaluable tools for revealing mechanisms, additional field studies are however needed to test ecological relevance of the observed effects. Although it is now possible to attract naturally occurring aphid predators in a crop field using semiochemicals, future work should more fully explore the broader ecological context in which signaling occurs. The information gained from a deeper understanding of the chemical ecology of aphid-natural enemy interaction will enhance our understanding of the chemical biology and ecology of aphids, and may facilitate the design of novel control strategies. [less ▲]

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See detailFeasibility study of burning neat jatropha oil into a vaporizing burner for household applications.
Sartor, Kevin ULg; Makaire, Danielle; Fontaine, Jean-Marie et al

in Proceedings (2016, August)

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See detailAharonov-Bohm oscillations of bosonic matter-wave beams in the presence of disorder and interaction
Chrétien, Renaud ULg; Dujardin, Julien; Petitjean, Cyril ULg et al

Poster (2016, July 27)

We study the one-dimensional (1D) transport properties of an ultracold gas of Bose-Einstein condensed atoms through Aharonov-Bohm (AB) rings. Our system consists of a Bose-Einstein condensate (BEC) that ... [more ▼]

We study the one-dimensional (1D) transport properties of an ultracold gas of Bose-Einstein condensed atoms through Aharonov-Bohm (AB) rings. Our system consists of a Bose-Einstein condensate (BEC) that is outcoupled from a magnetic trap into a 1D waveguide which is made of two semi-infinite leads that join a ring geometry exposed to a synthetic magnetic flux φ. We specifically investigate the effects both of a disorder potential and of a small atom-atom contact interaction strength on the AB oscillations. The main numerical tools that we use for this purpose are a mean-field Gross-Pitaevskii (GP) description and the truncated Wigner (tW) method. We find that a correlated disorder suppress the AB oscillations leaving thereby place to Aronov-Al’tshuler-Spivak (AAS) oscillations. The competition between disorder and interaction leads to a peak inversion at Φ = π, that is a signature of a coherent backscattering (CBS) peak inversion. This is confirmed by truncated Wigner simulations. [less ▲]

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See detailTweeting is not investing! But...
Choffray, Jean-Marie ULg

Diverse speeche and writing (2016)

So, that’s it! Hundreds of Tweets on The Art and Science of Investing to “show you the way”, to share my most recent observations on the behavior of the markets, and to illustrate some of the key ... [more ▼]

So, that’s it! Hundreds of Tweets on The Art and Science of Investing to “show you the way”, to share my most recent observations on the behavior of the markets, and to illustrate some of the key heuristics that I learned over the last twenty years. As, without any doubt, I am no Warren Buffett, feel free to disagree and develop you own “theory” of investing. Painful and solitary work... Success is at this price! And, based on what I did - and did not! - achieve, it shouldn’t be hard to do much better... That’s my wish for you! [less ▲]

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See detailHCOOH distributions from IASI for 2008-2014: comparison with ground-based FTIR measurements and a global chemistry-transport model
Pommier, M.; Clerbaux, C.; Coheur, P.-F. et al

in Atmospheric Chemistry and Physics (2016), 16

Formic acid (HCOOH) is one of the most abundant volatile organic compounds in the atmosphere. It is a major contributor to rain acidity in remote areas. There are, however, large uncertainties on the ... [more ▼]

Formic acid (HCOOH) is one of the most abundant volatile organic compounds in the atmosphere. It is a major contributor to rain acidity in remote areas. There are, however, large uncertainties on the sources and sinks of HCOOH and therefore HCOOH is misrepresented by global chemistry-transport models. This work presents global distributions from 2008 to 2014 as derived from the measurements of the Infrared Atmospheric Sounding Interferometer (IASI), based on conversion factors between brightness temperature differences and representative retrieved total columns over seven regions: Northern Africa, southern Africa, Amazonia, Atlantic, Australia, Pacific, and Russia. The dependence of the measured HCOOH signal on the thermal contrast is taken into account in the conversion method. This conversion presents errors lower than 20 % for total columns ranging between 0.5 and 1 × 1016 molec/cm2 but reaches higher values, up to 78 %, for columns that are lower than 0.3 × 1016 molec/cm2. Signatures from biomass burning events are highlighted, such as in the Southern Hemisphere and in Russia, as well as biogenic emission sources, e.g., over the eastern USA. A comparison between 2008 and 2014 with ground-based Fourier transform infrared spectroscopy (FTIR) measurements obtained at four locations (Maido and Saint-Denis at La Réunion, Jungfraujoch, and Wollongong) is shown. Although IASI columns are found to correlate well with FTIR data, a large bias (> 100 %) is found over the two sites at La Réunion. A better agreement is found at Wollongong with a negligible bias. The comparison also highlights the difficulty of retrieving total columns from IASI measurements over mountainous regions such as Jungfraujoch. A comparison of the retrieved columns with the global chemistry-transport model IMAGESv2 is also presented, showing good representation of the seasonal and interannual cycles over America, Australia, Asia, and Siberia. A global model underestimation of the distribution and a misrepresentation of the seasonal cycle over India are also found. A small positive trend in the IASI columns is observed over Australia, Amazonia, and India over the 2008–2014 period (from 0.7 to 1.5 %/year), while a decrease of ∼ 0.8 %/year is measured over Siberia. [less ▲]

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See detailClostridium difficile a new zoonotic agent? Assessment of human transmission potential of hypervirulent strains of Clostridium difficile through food products consumption
Rodriguez Diaz, Cristina ULg

Doctoral thesis (2016)

Clostridium difficile is a spore-forming anaerobic bacterium recognised as a major human pathogen responsible for pseudomembranous colitis and nosocomial-antibiotic associated diarrhea. Traditionally ... [more ▼]

Clostridium difficile is a spore-forming anaerobic bacterium recognised as a major human pathogen responsible for pseudomembranous colitis and nosocomial-antibiotic associated diarrhea. Traditionally, hospitals were considered the main reservoirs for infection. However, in the last years the incidence, deaths, complications and costs of C. difficile infection (CDI) have been rising, not only in healthcare facilities, but also within the community. In the community, it has been detected in a growing number of CDI cases in previously healthy individuals without antimicrobial exposure, hospital stay or any other classical risk factors. Furthermore, the disease has been repeatedly described in younger patients, including children. Some hypotheses have been proposed to explain this peak of community cases, the most obvious being that nowadays more attention is given to CDI surveillance. In the last years, diarrhea due to C. difficile disease might have gone undiagnosed, and in many cases went unreported, particularly in the community. Since 2004, severe outbreaks of CDI have been documented increasingly in the United States, Canada and in Europe. These outbreaks have been associated with the emergence of a novel strain, known as PCR-ribotype 027, characterised by higher than usual levels of toxins A and B production, and the presence of a third toxin named CDT or binary toxin. This strain type is also characterised by its resistance to both erythromycin and fluoroquinolones (i.e. moxifloxacin, gatifloxacin and levofloxacin). However, according to the latest hospital surveillance studies in Europe, since 2010 there is a decrease in the incidence rates of PCR-ribotype 027 while other PCR-ribotypes, including PCR-ribotypes 014, 020, 001, 002, 078 and 015 are increasing. Person to person contact is one source proposed for the spread in the community, occurring after visiting hospitalised patients or residents in long-term care facilities. Employees of these health-care settings can also carry spores and contaminate their entourage. The second hypothesis is contamination from the environment, following visits to a potentially contaminated place, such as hospitals or nursing homes. The two most important potential sources of CDI in the community, which have been demonstrated by investigations in the last decade are animals and foods. While C. difficile is also known as enteric pathogen in some food producing and companion animal species, there are several reports describing the presence of the bacterium in the intestinal contents of apparently healthy animals. Moreover, data published recently suggests animals as an important source of human CDI, which can spread disease through environmental contamination, direct or indirect contact, or food contamination, including carcass and meat contamination at slaughter or in the case of crops, through the use of organic animal manure. By definition, zoonoses are infectious diseases that can be transmitted directly or indirectly between animals and humans, through direct contact or close proximity with infected animals, or through the environment. Foodborne zoonotic pathogens are transmitted via the consumption of contaminated food or drink water. The first description of C. difficile in domestic animals and their environments dates from 1974 and possible foodborne transmission was reported for the first time in 1982. However, nowadays the importance of C. difficile as zoonotic disease remains largely unknown. The "One Health" concept is a worldwide strategy, which recognises that the health of humans and animals is connected and also depends on the environment. The present dissertation is a 5 year national study that has investigated the presence of C. difficile in animals and food, from “farm-totable”. The study was also extended to humans resident in a nursing home and in two hospitals in Belgium and in Spain. The characterisation of the isolates obtained has ultimately allowed comparison of the PCR-ribotype distribution in the different European hospitals, as well as with the PCR-ribotype distribution found in animals and foods. This work explores how C. difficile spreads among human patients, animals, foods and the environment to better understand the potential of the bacterium as a zoonotic or foodborne infectious agent. [less ▲]

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See detailNonlinear analysis of compliant mechanisms: application to tape springs
Dewalque, Florence ULg; Bruls, Olivier ULg

Poster (2016, July 07)

Brief summary of the mechanical behaviour of tape springs. Main results obtained by the means of finite element models. Description of the experimental set-up and results. See the extended abstract for ... [more ▼]

Brief summary of the mechanical behaviour of tape springs. Main results obtained by the means of finite element models. Description of the experimental set-up and results. See the extended abstract for more details. [less ▲]

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See detailNovel butanol pretreatment significantly improves delignification and saccharification of different lignocellulosic biomasses
Schmetz, Quentin ULg; Teramura, Hiroshi; Jacquet, Nicolas ULg et al

Poster (2016, July 07)

Organosolv pretreatment using diluted acid and butanol allows the separation of cellulose, hemicelluloses and lignin into three distinct phases. The butanol process has been investigated on six different ... [more ▼]

Organosolv pretreatment using diluted acid and butanol allows the separation of cellulose, hemicelluloses and lignin into three distinct phases. The butanol process has been investigated on six different biomasses: tall fescue, sugarbeet pulp, sugarcane bagasse, beech wood, eucalyptus and Japanese cedar. Dilute acid pretreatment has been performed under similar conditions for comparison. [less ▲]

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See detailRestricted interests in autism with versus without speech onset delay : the importance of perceptually versus thematically organized interests
Chiodo, Liliane ULg; Majerus, Steve ULg; Eusèbe, Sandrine et al

Poster (2016, July 07)

Objectives : To explore whether autistic adults with vs without speech delay also differ in the perceptual vs thematic nature of their restricted interests.

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See detailGamifier un quiz – Effet graduel sur la performance, l’immersion et la perception de compétence
le Maire, Nathalie ULg; Fauconnier, Marie-Laure ULg; Colaux, Catherine ULg et al

Conference (2016, July 06)

Dans un contexte marqué par l’arrivée d’une génération pour laquelle les technologies, les réseaux sociaux et les jeux en ligne relèvent de l’évidence (Stein, 2013; Weiler, 2004), le jeu a souvent été ... [more ▼]

Dans un contexte marqué par l’arrivée d’une génération pour laquelle les technologies, les réseaux sociaux et les jeux en ligne relèvent de l’évidence (Stein, 2013; Weiler, 2004), le jeu a souvent été qualifié de véhicule d’une pédagogie rendant l’étudiant acteur de son apprentissage, conférant une dimension de défi aux activités éducatives et générant une motivation intrinsèque (Foster, 2008; Kang & Tan, 2008; McFarlane et al., 2002; Mitchell & Savill-Smith, 2004; Papastergiou, 2009). Ce potentiel éducatif du jeu a cependant été souvent associé à des jeux immersifs (de Freitas, 2006) requérant la mise en œuvre d’une trame narrative et dont le développement peut s’avérer couteux. L’utilisation de mini-jeux est considérée comme une solution alternative à ces « serious games » complexes car ils permettent d’enseigner un grand nombre de concepts tout en générant de faibles coûts de développement (Illanas, Gallego, Satorre, & Llorens, 2008). Ceux-ci présentent des règles basiques, sont faciles à jouer et conçus comme objets d’apprentissage de sorte qu’il soit aisé pour l’étudiant de percevoir les informations essentielles et que leur pratique soit bénéfique pour l’apprentissage (Frazer, Argles, & Wills, 2007). La gamification, à savoir la transposition des principes issus de l’univers du jeu au domaine de l’éducation (Deterding, Dixon, Khaled, & Nacke, 2011), ne porte donc pas ici sur des jeux de simulation immersifs mais vise plus réalistement la transposition à des activités d’apprentissage d’un certain nombre de principes et de leviers à l’œuvre dans des mini-jeux populaires tel que Candy Crush. La question de recherche qui a guidé l’expérience décrite ci-après concerne l’évaluation du potentiel pédagogique de l’utilisation d’un mini-jeu de ce type dans un cours de chimie générale en complément des supports pédagogiques plus classiquement utilisés en première année d’université. Concrètement, ce mini-jeu appelé « Atomica » se présente comme un quiz d’entrainement portant sur un chapitre réputé difficile du cours, l’atomistique. Ce quiz a fait l’objet de quatre versions activant chacune un nombre croissant d’éléments de gamification (indiqués en gras) décrits par plusieurs auteurs comme étant les « ingrédients » ou « building blocks » d’un bon jeu (Bunchball Inc., 2010; Dignan, 2011; Reeves & Read, 2013) : - La version contrôle du QCM se présente comme similaire aux évaluations formatives couramment utilisées à l’université ; - La version 1 segmente le QCM en six niveaux de difficulté ; - La version 2 ajoute un feedback automatisé aux niveaux de difficulté ; - La version 3 présente une version maximaliste de la gamification puisque, aux éléments précédents, elle ajoute un compte à rebours, des indices dont l’appel engendre une perte de points, un classement des meilleurs joueurs et un indicateur social (possibilité de se situer par rapport à la communauté de joueurs). Ce choix d’un dispositif graduel se justifie notamment par l’intérêt pour la détection d’un seuil à partir duquel l’ajout d’éléments de gamification fait basculer la perception d’un quiz habituel vers un artefact relevant du mini-jeu et générant ainsi un état de flow chez le joueur. Chaque version a été soumise à un groupe d’une trentaine d’étudiants, selon une procédure expérimentale contrôlée, avec pour objectif la collecte de données (en cours) sur : - L’état de flow ou expérience optimale engendré par chacune des versions (orientation comparative) défini comme un état subjectif de bien-être (Csikszentmihalyi, 1990) engendrant une immersion totale dans l’activité. Afin de mesurer le flow, une échelle spécifique aux jeux éducatifs (EGameFlow) développée en 2009 (Fu, Su, & Yu, 2009) a été utilisée dans le cadre de cette étude. - Une des trois composantes du modèle de la dynamique motivationnelle de Viau, la perception du sentiment de compétence (Bandura, 1993; Pajares, 2014) considéré comme un moteur essentiel à l’apprentissage et un déterminant de l’intérêt pour une discipline scolaire. - La performance à un test de connaissance soumis aux étudiants avant et après l’expérience de jeu. Les motivations sous-tendant le processus d’exploration des mini-jeux sont à chercher du côté d’un certain discours pédagogique qui prône l’inscription d’une dimension ludique dans les apprentissages en enseignement supérieur. Nourrie par ses résultats expérimentaux, la communication proposera un retour réflexif plus général sur la valeur, les limitations et les conditions de réalisation de ce discours. [less ▲]

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See detailEtude de la composition chimique de Pseudotsuga menziesii (Mirb.) Franco et évaluation de l’impact de divers prétraitements lignocellulosiques sur l’extraction de la lignine
Berchem, Thomas ULg; Schmetz, Quentin ULg; Jacquet, Nicolas ULg et al

Poster (2016, July 06)

La raréfaction des ressources fossiles est une certitude à l’heure actuelle. Il est donc primordial de trouver des voies de production plus durables pour des produits de consommation courante. Le ... [more ▼]

La raréfaction des ressources fossiles est une certitude à l’heure actuelle. Il est donc primordial de trouver des voies de production plus durables pour des produits de consommation courante. Le bioraffinage fait partie des solutions envisagées pour substituer les matériaux originaires de la filière pétrochimique. Dans cette optique, ce travail se focalise sur l’extraction et la caractérisation de la lignine à partir d’une biomasse présente en abondance en région Wallonne, Pseudotsuga menziesii (Mirb.) Franco (Douglas). Ce travail vise à montrer l’impact de divers prétraitements lignocellulosiques, tant en terme de rendements et de pureté d’extraction qu’au niveau de la modification de la structure et des propriétés des lignines. Ces différents paramètres sont évalués par des techniques gravimétriques (Klason), chromatographiques (chromatographie d’exclusion stérique) et spectroscopiques (RMN 2D HSQC). Pseudotsuga menziesii (Mirb.) Franco a été préalablement caractérisé par son taux de matière lignocellulosique (cellulose, hémicelluloses, lignine), ainsi que sa teneurs en cendres, en protéines et en extractibles (à l’eau et à l’éthanol). Les lignines natives ont été caractérisées par RMN 2D HSQC. [less ▲]

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See detailOptimisation de la production d’acide furan-2,5-dicarboxylique à partir de déchets verts pour la conception de plastiques bio-basés
Istasse, Thibaut ULg; Jacquet, Nicolas ULg; Richel, Aurore ULg

Poster (2016, July 06)

Afin de trouver des alternatives renouvelables aux produits issus de l’industrie pétrochimique, de nombreuses voies de recherches ont été explorées. Une voie prometteuse est la technologie des dérivés ... [more ▼]

Afin de trouver des alternatives renouvelables aux produits issus de l’industrie pétrochimique, de nombreuses voies de recherches ont été explorées. Une voie prometteuse est la technologie des dérivés furaniques. Parmi ces composés, le 5-hydroxyméthylfurfural (5-HMF) fait partie des molécules plateformes les plus importantes1. Il s’agit d’un produit de dégradation obtenu par déshydratation des hexoses2,3. Le 5-HMF peut servir de base à la conception de nombreuses molécules valorisables comme l’acide furan-2,5-dicarboxylique dont la structure proche de l’acide téréphtalique permet des applications dans la conception de polymères bio-basés3. L’acide furan-2,5-dicarboxylique respecte la législation REACH selon l’European Chemicals Agency4. Un rapport de l’EFSA de 2014 a démontré que cette substance ne posait pas de problème de toxicité lors de son utilisation comme monomère de base dans les plastiques d’emballage pour aliments5. Selon la société Avantium, le FDCA peut être utilisé pour produire un plastique entièrement bio-basé, le polyéthylène furanoate (PEF), qui affiche des performances supérieures à celle du poléthylène téréphtalate (PET) en termes de stabilité thermique, de propriétés mécaniques et de perméabilité aux gaz6. Si le FDCA peut être convertit en de nombreux produits à haute valeur ajoutée, il existe toutefois un frein majeur à son exploitation industrielle : son précurseur, le 5-HMF, n’est pas encore produit en grande quantité1. Ce problème est dû principalement à la déshydratation non sélective des sucres de la biomasse qui aboutit à de nombreux autres produits que le 5-HMF. La première difficulté à surmonter est donc la mise au point d’un procédé permettant de déshydrater de manière efficace et sélective les sucres de la biomasse. Le 5-HMF est également peu stable en milieu acide où il se décompose en acide formique et en acide lévulinique2. L'enjeu du projet de recherche présenté est donc l’optimisation de la production de 5-HMF à partir d’un ou plusieurs types de biomasses dans un premier temps, puis l’optimisation de la conversion du 5-HMF produit en FDCA. Les paramètres à prendre en compte sont notamment les sources de biomasse, l’efficacité des prétraitements concernant l’extraction des sucres, la sélectivité et l’efficacité de la conversion de ces sucres en 5-HMF (système mono- ou biphasique), l’étude de divers catalyseurs, le coût des traitements, etc… [less ▲]

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See detailFirst characterization and validation of FORLI-HNO3 vertical profiles retrieved from IASI/Metop
Ronsmans, G.; Langerock, B.; Wespes, C. et al

in Atmospheric Measurement Techniques. Papers in Open Discussion (2016), 2016

Knowing the spatial and seasonal distributions of nitric acid (HNO3) around the globe is of great interest to apprehend the processes regulating stratospheric ozone, especially in the polar regions ... [more ▼]

Knowing the spatial and seasonal distributions of nitric acid (HNO3) around the globe is of great interest to apprehend the processes regulating stratospheric ozone, especially in the polar regions. Thanks to its unprecedented spatial and temporal sampling, the nadir-viewing Infrared Atmospheric Sounding Interferometer (IASI) allows sounding the atmosphere twice a day globally, with good spectral resolution and low noise. With the Fast Optimal Retrievals on Layers for IASI (FORLI) algorithm, we are retrieving, in near-real time, columns as well as vertical profiles of several atmospheric species, amongst which is HNO3. We present in this paper the first characterization of the FORLI-HNO3 profile products, in terms of vertical sensitivity and error budgets. We show that the sensitivity of IASI to HNO3 is highest in the lower stratosphere (10–20km), where the largest amounts of HNO3 are found, but that the vertical sensitivity of IASI only allows one level of information on the profile (DOFS 1). The sensitivity near the surface is negligible in most cases, and for this reason, a partial column (5–35km) is used for the analyses. Both vertical profiles and partial columns are compared to FTIR ground-based measurements from the Network for the Detection of Atmospheric Composition Change (NDACC) to characterize the accuracy and precision of the FORLI-HNO3 product. The profile validation is conducted through the smoothing of the raw FTIR profiles by the IASI averaging kernels and gives good results, with a slight overestimation of IASI measurements in the Upper Troposphere-Lower Stratosphere (UTLS) at the 6 chosen stations (Thule, Kiruna, Jungfraujoch, Izaña, Lauder and Arrival Heights). The validation of the partial columns (5–35km) is also conclusive with a mean correlation of 0.93 between IASI and the FTIR measurements. An initial survey of the HNO3 spatial and seasonal variabilities obtained from IASI measurements for a one year (2011) data set shows that the expected latitudinal gradient of concentrations from low to high latitudes and the large seasonal variability in polar regions (cycle amplitude around 30% of the seasonal signal, peak-to-peak) are well represented with IASI data. [less ▲]

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See detailHigh-temperature and quantitative XRD study of typical Westerwald clays (Germany)
Fontaine, François ULg; Fagel, Nathalie ULg

Poster (2016, July 05)

The Westerwald is one of the largest and oldest clay mining area of Germany. Those deposits were formed during the Eocene and Oligocene as a result of the weathering, erosion and redeposition of Devonian ... [more ▼]

The Westerwald is one of the largest and oldest clay mining area of Germany. Those deposits were formed during the Eocene and Oligocene as a result of the weathering, erosion and redeposition of Devonian rocks. During the Miocene, intense volcanic activities led to a large basalt cover, protecting the clays from the erosion. The fine fraction is mainly composed of kaolinite and illite, with the possible presence of interstratified I S. Other minerals such as quartz, feldspars, hematite, goethite or anatase are present in variable concentrations. Four typical Westerwald clays were chosen for this study: kaolinite-rich clay, kaolinite-illite clay, a red and a yellow firing clays. The first goal is to perform quantitative XRD using two different methods and to compare them: reference intensity ratio (RIR) and Rietveld (using Topas and BGMN). The second goal is the study of those samples using high-temperature XRD (HTXRD). The samples were heated up to 1250°C and a XRD pattern was obtained in situ every 100°C. The results show the temperatures of vitrification and formation of mullite and cristobalite varying from one sample to another, which is mainly linked to their flux concentration. [less ▲]

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