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See detailLa resiliencia comunitaria en el centro de la mitigacion de amenazas naturales: un breve estado del arte
Schmitz, Serge ULg

in Hermesse, Julie; Schmitz, Serge; Servais, Olivier (Eds.) et al Ordenamiento territorial en la prevención de desastres (in press)

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See detailExperimental and computational micro–mechanical investigations of compressive properties of polypropylene/multi–walled carbon nanotubes nanocomposite foams
Wan, Fangyi; Tran, Minh Phuong; Leblanc, Christophe ULg et al

in Mechanics of Materials (in press)

The compressive behavior of nanocomposite foams is studied by both experimental and computational micro-mechanics approaches with the aim of providing an efficient computational model for this kind of ... [more ▼]

The compressive behavior of nanocomposite foams is studied by both experimental and computational micro-mechanics approaches with the aim of providing an efficient computational model for this kind of material. The nanocomposites based on polypropylene (PP) and different contents of multi-walled carbon nanotubes (CNTs) are prepared by melt mixing method. The nanocomposite samples are foamed using super-critical carbon dioxide (ScCO2) as blowing agent at different soaking temperatures. The influence of this foaming parameter on the morphological characteristics of the foam micro-structure is discussed. Differential Scanning Calorimetry (DSC) measurements are used to quantify the crystallinity degree of both nanocomposites and foams showing that the crystallinity degree is reduced after the foaming process. This modification leads to mechanical properties of the foam cell walls that are different from the raw nanocomposite PP/CNTs material. Three--point bending tests are performed on the latter to measure the flexural modulus in terms of the crystallinity degree. Uniaxial compression tests are then performed on the foamed samples under quasi-static conditions in order to extract the macro-scale compressive response. Next, a two-level multi-scale approach is developed to model the behavior of the foamed nanocomposite material. On the one hand, the micro-mechanical properties of nanocomposite PP/CNTs cell walls are evaluated from a theoretical homogenization model accounting for the micro-structure of the semi-crystalline PP, for the degree of crystallinity, and for the CNT volume fraction. The applicability of this theoretical model is demonstrated via the comparison with experimental data from the described experimental measurements and from literature. On the other hand, the macroscopic behavior of the foamed material is evaluated using a computational micro-mechanics model using tetrakaidecahedron unit cells and periodic boundary conditions to estimate the homogenized properties. The unit cell is combined with several geometrical imperfections in order to capture the elastic collapse of the foamed material. The numerical results are compared to the experimental measurements and it is shown that the proposed unit cell computational micro-mechanics model can be used to estimate the homogenized behavior, including the linear and plateau regimes, of nanocomposite foams. [less ▲]

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See detailp-regularity of the p-adic valuation of the Fibonacci sequence
Medina, Luis; Rowland, Eric ULg

in Fibonacci Quarterly (The) (in press)

We show that the p-adic valuation of the sequence of Fibonacci numbers is a p-regular sequence for every prime p. For p≠2,5, we determine that the rank of this sequence is α(p)+1, where α(m) is the ... [more ▼]

We show that the p-adic valuation of the sequence of Fibonacci numbers is a p-regular sequence for every prime p. For p≠2,5, we determine that the rank of this sequence is α(p)+1, where α(m) is the restricted period length of the Fibonacci sequence modulo m. [less ▲]

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See detailComment la participation à une recherche contribue au développement professionnel : le cas des exemples à l’Université
Fossion, Gilles ULg; Faulx, Daniel ULg

in Recherches Qualitatives (in press)

La recherche scientifique constitue un des piliers centraux de l’activité universitaire. Nous nous sommes donc questionnés sur les apprentissages générés par celle-ci. Après avoir brièvement décrit les ... [more ▼]

La recherche scientifique constitue un des piliers centraux de l’activité universitaire. Nous nous sommes donc questionnés sur les apprentissages générés par celle-ci. Après avoir brièvement décrit les objectifs et enjeux de cette communication, nous proposons une présentation des objectifs et de la méthodologie de la recherche que nous avons menée au sein des Facultés de Psychologie et des Sciences de l’Éducation de l’Université de Liège. Nous poursuivons, enfin, par la mise en évidence de ses principaux résultats. Ces résultats se situent sur deux niveaux. D’une part, nous présentons les résultats inhérents à la recherche - relative aux impacts générés par la mobilisation de l’exemple au sein du discours pédagogique - et qui contribue à l’enrichissement du champ scientifique abordé. D’autre part, nous abordons les résultats qui permettent la mise en évidence de l’aspect formatif que revêt la participation à une recherche scientifique pour les acteurs. [less ▲]

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See detailCariteo
Amendola, Cristiano ULg

in Frare, Pierantonio; Langella, Giuseppe; Frasso, Giuseppe (Eds.) Dizionario Biblico della Letteratura Italiana (in press)

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See detailContribution of the Finite Volume Point Dilution Method for measurement of groundwater fluxes in a fractured aquifer
Jamin, Pierre ULg; Goderniaux, Pascal; Bour, Olivier et al

in Journal of Contaminant Hydrology (in press)

Measurement of groundwater fluxes is the basis of all hydrogeological study, from hydraulics characterization to the most advanced reactive transport modelling. Usual groundwater fluxes estimation with ... [more ▼]

Measurement of groundwater fluxes is the basis of all hydrogeological study, from hydraulics characterization to the most advanced reactive transport modelling. Usual groundwater fluxes estimation with Darcy’s law may lead to cumulated errors on spatial variability, especially in fractured aquifers where local direct measurement of groundwater fluxes becomes necessary. In the present study, both classical Point Dilution Method (PDM) and Finite Volume Point Dilution Method (FVPDM) are compared on the fractured crystalline aquifer of Ploemeur, France. The manipulation includes the first use of the FVPDM in a fractured aquifer using a double packer. This configuration limits the vertical extend of the tested zone to target a precise fracture zone of the aquifer. The result of this experiment is a continuous monitoring of groundwater fluxes that lasted for more than 4 days. Measurements of groundwater flow rate in the fracture (Qt) by PDM provide good estimates only if the mixing volume (Vw) (volume of water in which the tracer is mixed) is precisely known. Conversely, the FVPDM allows for an independent estimation of Vw and Qt, leading to better precision in case of complex experimental setup such as the one used. The precision of a PDM does not rely on the duration of the experiment while a FVPDM may require long experimental duration to guarantees a good precision. Classical PDM should then be used for rapid estimation of groundwater flux using simple experimental setup. On the other hand, the FVPDM is a more precise method that has a great potential for development but may require longer duration experiment to achieve a good precision if the groundwater fluxes investigated are low and/or the mixing volume is large. [less ▲]

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See detailDrying induced shrinkage of Boom Clay: an experimental investigation
Prime, Noémie; Levasseur, Séverine; Miny, Laurent et al

in Canadian Geotechnical Journal (in press)

Drying induced shrinkage of geomaterials may have a strong effect on geostructure stability and deformation. Settlement of foundations, fracture opening on slopes, roads, tunnel walls may be due to drying ... [more ▼]

Drying induced shrinkage of geomaterials may have a strong effect on geostructure stability and deformation. Settlement of foundations, fracture opening on slopes, roads, tunnel walls may be due to drying shrinkage. However, there is still a lack of knowledge concerning shrinkage evolution in time and shrinkage propagation within the material. In this study, the shrinkage of a specific clayey rock, Boom Clay, under drying conditions is experimentally investigated. This rock is a deep geological formation which is under study for high-level and long-life radioactive waste storage in Belgium. Two experimental campaigns are here presented. The first one, based on vapour equilibrium drying technique and completed by sample size manual measurement, aims to characterize the material shrinkage in balanced states. The second one, based on convective drying technique completed by shape monitoring using X-ray tomography, aims to analyse how shrinkage develops before reaching a steady state. Both approaches put in evidence the shrinkage anisotropy of this structurally bedded rock, with a ratio around 2 between the direction of maximum strains and the direction of minimum strains. However, the two drying techniques also provide complementary results, as the relation between the amount of shrinkage and the retention curve (for the uniform drying imposed with saline solutions) and the kinetics of shrinkage propagation inside the material (for the non-uniform drying imposed with air convection). [less ▲]

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See detailDeveloping biodiversity indicators on a stakeholders' opinions basis: the gypsum industry Key Performance Indicators framework.
Pitz, Carline ULg; Mahy, Grégory ULg; Vermeulen, Cédric ULg et al

in Environmental Science and Pollution Research (in press)

Aims: To establish a common Key Performance Indicators (KPIs) framework for reporting about the gypsum industry biodiversity at the European level. Methods: In order to integrate different opinions and to ... [more ▼]

Aims: To establish a common Key Performance Indicators (KPIs) framework for reporting about the gypsum industry biodiversity at the European level. Methods: In order to integrate different opinions and to reach a consensus framework, an original participatory process approach has been developed among different stakeholder groups: Eurogypsum, European and regional authorities, universities scientists, consulting offices, European and regional associations for the conservation of nature and the extractive industry. The strategy is developed around four main steps: (i) building of a maximum set of indicators to be submitted to stakeholders based on the literature (Focus Group method); (ii) evaluating the consensus about indicators through a policy Delphi survey aiming at the prioritization of indicator classes using the Analytic Hierarchy Process method (AHP) and of individual indicators; (iii) testing acceptability and feasibility through analysis of Environmental Impact Assessments (EIAs) and visits to three European quarries; (iv) Eurogypsum final decision and communication. Results: The resulting framework contains a set of 11 indicators considered the most suitable for all the stakeholders. Conclusions: Our KPIs respond to European legislation and strategies for biodiversity. The framework aims at improving sustainability in quarries and at helping to manage biodiversity as well as to allow the creation of coherent reporting systems. The final goal is to allow for the definition of the actual biodiversity status of gypsum quarries and allow for enhancing it. The framework is adaptable to the local context of each gypsum quarry. [less ▲]

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See detailInfluence of the macromolecular surfactant features and reactivity on morphology and surface properties of emulsion-templated porous polymers
Mathieu, Kevin ULg; Jérôme, Christine ULg; Debuigne, Antoine ULg

in Macromolecules (in press)

This work investigates key parameters of a straightfor- ward macromolecular surfactant-assisted functionalization strategy of porous polymers produced by high internal phase emulsion (HIPE) polymerization ... [more ▼]

This work investigates key parameters of a straightfor- ward macromolecular surfactant-assisted functionalization strategy of porous polymers produced by high internal phase emulsion (HIPE) polymerization. For that purpose, a series of well-defined amphiphilic poly(ethylene oxide)-b-poly(styrene) (PEO-b-PS) copolymers with various compositions and molar masses were synthesized by radical addition−fragmentation chain transfer (RAFT) polymerization and used as macromolecular surfactants for the emulsion-templated polymerization of styrene/divinylbenzene (S/DVB). The morphology of the resulting foams, referred to as polyHIPEs, was found dependent on the PS block length and concentration of the block copolymer surfactant in the emulsion. Moreover, we determined the lowest PS block length required for preserving the anchoring of the copolymer at the surface by physical entanglement within the S/DVB cross-linked matrix leading to a PEO-coated porous material. The functionalization of the porous monoliths with PEO was evidenced by sessile drop shape analyses and water uptake experiments. The chemical anchoring of the PEO-b-PS at the surface of polyHIPEs was also explored by interfacial initiation of the HIPE polymerization from a PEO-b-PS-RAFT macroinitiator leading to porous structures with permanent PEO coatings. In this case, copolymerizing DVB with acrylate instead of styrene improved the interconnectivity of the porous monoliths. [less ▲]

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See detailWhen microplastic is not plastic: the ingestion of artificial cellulose fibers by macrofauna living in seagrass macro-phytodetritus.
Remy, François ULg; Collard, France ULg; Gilbert, Bernard ULg et al

in Environmental Science & Technology (in press)

Dead leaves of the Neptune grass, Posidonia oceanica (L.) Delile, in the Mediterranean coastal zone, are colonized by an abundant “detritivorous” invertebrate community that is heavily predated by fishes ... [more ▼]

Dead leaves of the Neptune grass, Posidonia oceanica (L.) Delile, in the Mediterranean coastal zone, are colonized by an abundant “detritivorous” invertebrate community that is heavily predated by fishes. This community was sampled in August 2011, November 2011 and March 2012 at two different sites in the Calvi Bay (Corsica). Ingested artificial fibers (AFs) of various sizes and colors were found in 27.6% of the digestive tracts of the nine dominant species regardless of their trophic level or taxon. No seasonal, spatial, size or species-specific significant differences were revealed; suggesting that invertebrates ingest AFs at constant rates. Results showed that, in the gut contents of invertebrates, varying by trophic level, and across trophic levels, the overall ingestion of AFs was low (approximately 1 fiber per organism). Raman spectroscopy revealed that the ingested AFs were composed of viscose, an artificial, cellulose-based polymer. Most of these AFs also appeared to have been colored by industrial dyes. Two dyes were identified: Direct Blue 22 and Direct Red 28. The latter is known for being carcinogenic for vertebrates, potentially causing environmental problems for the P. oceanica litter community. Techniques such as Raman spectroscopy are necessary to investigate the particles composition, instead of relying on fragment size or color to identify the particles ingested by animals. [less ▲]

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See detailSynthesis of aliphatic polyamide bearing fluorinated groups from ε-caprolactam and modified cyclic lysine
Tunc, Deniz; Bouchekiv, Hassen; Ameduri, Bruno et al

in European Polymer Journal (in press)

Aliphatic polyamide (PA) bearing fluorinated groups was synthesized in bulk with perfluorobutyryl-substituted α-amino-ε-caprolactam and ε-caprolactam by anionic ring-opening polymerization (AROP). The ... [more ▼]

Aliphatic polyamide (PA) bearing fluorinated groups was synthesized in bulk with perfluorobutyryl-substituted α-amino-ε-caprolactam and ε-caprolactam by anionic ring-opening polymerization (AROP). The fluorinated monomer was obtained by condensation between cyclic lysine (i.e. α-amino-ε-caprolactam) and perfluorobutyrylchloride. The effect of the fluorinated monomer fraction onto the AROP of ε-caprolactam was monitored by the exothermicity of this polymerization versus time. The properties and characteristics of the resulting polymers were studied by with differential scanning calorimetry, thermogravimetry, magic angle spining NMR, FT-IR, and contact angle measurements. Polyamides bearing fluorinated groups exhibited better thermal stability than polyamide 6 (PA6) as well as a higher hydrophobic surface character as evidenced by surface tension measurements. The glass transition temperature of polyamide 6 was 53 °C and rose to 58 °C for a PA bearing fluorinated moieties, while fluorinated monomer insertion induced a decrease of the melting points from 216 to 198 °C. These copolymers displayed a maximum degradation temperature of 390 °C as compared to the 310 °C for PA6, and their surface energies decreased from 49.4 mN.cm-1 (PA6 value) to 44.1 mN.cm-1. [less ▲]

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See detailAmphibians forgo aquatic life in response to alien fish introduction
Winandy, Laurane ULg; Darnet, Elodie; Denoël, Mathieu ULg

in Animal Behaviour (in press)

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See detailMultivariate coefficients of variation: comparison and influence functions
Aerts, Stéphanie ULg; Haesbroeck, Gentiane ULg; Ruwet, Christel ULg

in Journal of Multivariate Analysis (in press)

In the univariate setting, coefficients of variation are well-known and used to compare the variability of populations characterized by variables expressed in different units or having really different means ... [more ▼]

In the univariate setting, coefficients of variation are well-known and used to compare the variability of populations characterized by variables expressed in different units or having really different means. When dealing with more than one variable, the use of such a relative dispersion measure is much less common even though several generalizations of the coefficient of variation to the multivariate setting have been introduced in the literature. In this paper, the lack of robustness of the sample versions of the multivariate coefficients of variation (MCV) is illustrated by means of influence functions and some robust counterparts based either on the Minimum Covariance Determinant (MCD) estimator or on the S estimator are advocated. Then, focusing on two of the considered MCV’s, a diagnostic tool is derived and its efficiency in detecting observations having an unduly large effect on variability is illustrated on a real-life data set. The influence functions are also used to compute asymptotic variances under elliptical distributions, yielding approximate confidence intervals. Finally, simulations are conducted in order to compare, in a finite sample setting, the performance of the classical and robust MCV’s in terms of variability and in terms of coverage probability of the corresponding asymptotic confidence intervals. [less ▲]

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See detailThe np- Control Charts with the Guaranteed In-Control Performance
Faraz, Alireza ULg; Heuchenne, Cédric ULg

E-print/Working paper (2016)

In this paper, we evaluate the in-control performance of np-control charts with estimated parameters. We then apply the bootstrap method to adjust the control charts’ limits to guarantee the desired in ... [more ▼]

In this paper, we evaluate the in-control performance of np-control charts with estimated parameters. We then apply the bootstrap method to adjust the control charts’ limits to guarantee the desired in-control average run length (ARL0) value in monitoring stage. The adjusted limits ensure that ARL0 would take a value greater than the desired value (say, B) with a certain specified probability, that is Pr⁡(ARL_0>B)=1-ρ. We finally provide users with tables which with practitioners do not need to do bootstrapping Phase I data set to obtain the control limit thresholds. [less ▲]

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See detailColère des agriculteurs, à qui la faute?
Habran, Maxime ULg

E-print/Working paper (2016)

Depuis le début de l’été, la colère gronde du côté des agriculteurs et pour cause, les prix du lait et de la viande ont atteint des seuils dangereusement bas. Que ce soit en France ou en Belgique, le ... [more ▼]

Depuis le début de l’été, la colère gronde du côté des agriculteurs et pour cause, les prix du lait et de la viande ont atteint des seuils dangereusement bas. Que ce soit en France ou en Belgique, le combat est le même. Les agriculteurs veulent des prix plus élevés pour la viande et pour le lait car actuellement ceux-ci sont inférieurs aux coûts de production. Cette note a pour objectif de répondre à trois questions : d’où vient la crise, quelles sont les solutions et les mesures prises sont-elles suffisantes ? [less ▲]

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See detailEVALUATION OF FISH EXPOSURE TO POP-LIKE (ORGANOTIN) COMPOUNDS IN SEPETIBA BAY (RIO DE JANEIRO STATE, BRAZIL) THROUGH HEPATIC TOTAL TIN CONCENTRATIONS
Paiva, TC; Schilithz, PF; Bisi, TL et al

in Organohalogen Compounds (2016, August)

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See detailPolitique agricole commune. Analyse transversale de la conditionnalité environnementale
Habran, Maxime ULg

Book published by Bruylant (2016)

Pierre angulaire de la construction européenne, la politique agricole commune (PAC) est à l’origine mise en place dans le but d’assurer l’autosuffisance alimentaire de la Communauté européenne. L’objectif ... [more ▼]

Pierre angulaire de la construction européenne, la politique agricole commune (PAC) est à l’origine mise en place dans le but d’assurer l’autosuffisance alimentaire de la Communauté européenne. L’objectif, rapidement atteint, laisse dans son sillage des stocks et excédents considérables ainsi que des dépenses communautaires importantes. Le mode de production agricole basé sur un modèle productiviste montre rapidement ses limites, obligeant les États membres à une réorientation de la PAC. Cette politique sera modifiée et réformée à de nombreuses reprises. La reconnaissance de la protection de l’environnement comme politique transversale contraint les États membres à l’adapter. D’une politique productiviste, elle devient attentive aux considérations environnementales, intégrant ces dernières dans chacune des réformes, allant même jusqu’à lier l’octroi de paiement au respect de règles essentiellement environnementales. Cet ouvrage présente la manière dont s’articule la relation entre les deux politiques autour de la notion de conditionnalité environnementale. À travers une étude minutieuse de chaque réforme de la PAC, une analyse de transversalité permet de saisir les enjeux et les motivations de l’intégration environnementale. [less ▲]

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See detailAn Exact Method for Designing Shewhart X ̅ and S2 Control Charts to Guarantee the In-Control Performance
Faraz, Alireza ULg; Heuchenne, Cédric ULg

in Journal of Quality Technology (2016)

The in-control performance of the Shewhart X ̅ and S2 control charts with estimated in-control parameters has been evaluated by a number of authors. Results indicate an unrealistically large amount of ... [more ▼]

The in-control performance of the Shewhart X ̅ and S2 control charts with estimated in-control parameters has been evaluated by a number of authors. Results indicate an unrealistically large amount of Phase I data is needed to have the desired in-control average run length (ARL) value in Phase II. To overcome this problem, it has been recommended that the control limits be adjusted based on a bootstrap method to guarantee that the in-control ARL is at least a specified value with a certain specified probability. In our paper we present simple formulas for the required control limits so that practitioners do not have to use the bootstrap method. An assumption of normality is required. The advantage of our proposed method is in its simplicity; there is no bootstrapping and the control chart constants do not depend on the Phase I sample data. [less ▲]

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See detailEspace, temps et angoisse psychotique : à propos d'un cas magistral
Englebert, Jérôme ULg

Scientific conference (2016, March 26)

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See detailSaint Genet et le dépassement de la situation : Création d’une clinique sartrienne
Englebert, Jérôme ULg

Scientific conference (2016, March 09)

Nous proposons de partir de Saint Genet : Comédien et Martyr (1952), monumentale psychobiographie de Sartre, pour évoquer une première lecture de la temporalité sartrienne et particulièrement des notions ... [more ▼]

Nous proposons de partir de Saint Genet : Comédien et Martyr (1952), monumentale psychobiographie de Sartre, pour évoquer une première lecture de la temporalité sartrienne et particulièrement des notions d’« instant » et de « conversion ». Le sujet clinique sur lequel s’appuiera notre propos et qui retiendra notre attention est l’incendiaire (dont on rappellera la différence avec le pyromane). Ensuite, nous convoquerons, et confondrons, L’esquisse d’une théorie des émotions (1933) et les Questions de Méthodes (1957). Ces deux points de repère nous permettront de reprendre le cas Genet et sa réaction à la lecture du volume que Sartre lui a consacré. D’importantes questions méthodologiques en psychologie clinique naîtront de ce développement et feront émerger une perspective « en double spirale » et la décisive question du corps. [less ▲]

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