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See detailMultidisciplinary approaches and fractionations to study lower termite symbiotic system and ligno-cellulose digestion
Bauwens, Julien ULg; Brasseur, Catherine ULg; Tarayre, Cédric ULg et al

Poster (2014, August)

Wood-feeding termites are a considerable source of enzymes active on ligno-cellulosic compounds. These enzymes are produced by the termite host and some representatives of its symbiotic microbial ... [more ▼]

Wood-feeding termites are a considerable source of enzymes active on ligno-cellulosic compounds. These enzymes are produced by the termite host and some representatives of its symbiotic microbial community, and are of particular interest in regard second generation biofuel. However, the complexity of microbial interactions renders micro-organisms isolation very difficult. Culture-independent methods permitted to gather a large amount of data and to understand a little more the role of each microbial population, particularly the prokaryotes. Proteomics allows working on the final product of gene expression, and corresponds more to the real operation of the digestive system. In order to investigate such a complex system, it is necessary to use multidisciplinary approaches and to fractionate this system. Zymography or affinity chromatography are used in parallel of routine proteomics techniques such as two-dimensional gel electrophoresis associated to MALDI-TOF mass spectrometry and nano-LC ESI-MS/MS. We used an artificial-diet based rearing to induce changes in microbial population balance. We performed preliminary assay to investigate the glycosylated proteome in the hindgut of a lower termite, using Multi-Lectin Affinity Chromatography (M-LAC) and enzymatic activity of harvested fractions was assessed on cellulosic substrates. [less ▲]

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See detailCombining magnetic and seismic studies to constrain processes in massive stars
Neiner, C.; Degroote, P.; Coste, B. et al

in IAUS 302 - Magnetic Fields Throughout Stellar Evolution (2014, August)

The presence of pulsations influences the local parameters at the surface of massive stars and thus it modifies the Zeeman magnetic signatures. Therefore it makes the characterisation of a magnetic field ... [more ▼]

The presence of pulsations influences the local parameters at the surface of massive stars and thus it modifies the Zeeman magnetic signatures. Therefore it makes the characterisation of a magnetic field in pulsating stars more difficult and the characterisation of pulsations is thus required for the study of magnetic massive stars. Conversely, the presence of a magnetic field can inhibit differential rotation and mixing in massive stars and thus provides important constraints for seismic modelling based on pulsation studies. As a consequence, it is necessary to combine spectropolarimetric and seismic studies for all massive classical pulsators. Below we show examples of such combined studies and the interplay between physical processes. [less ▲]

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See detailAuroral emissions of Jupiter and Saturn and satellite footprints
Radioti, Aikaterini ULg

Conference (2014, August)

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See detailÉvaluer la force de l’association
Bruyère, Olivier ULg; Boutron-Ruault, Marie-Christine

in Medi-Sphere (2014), 451

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See detailMulti-period vehicle loading with stochastic release dates
Arda, Yasemin ULg; Crama, Yves ULg; Kronus, David ULg et al

in EURO Journal on Transportation and Logistics (2014), 3(2), 93-119

This paper investigates a multi-period vehicle loading problem with stochastic information regarding the release dates of items to be transported. The deterministic version of the problem can be ... [more ▼]

This paper investigates a multi-period vehicle loading problem with stochastic information regarding the release dates of items to be transported. The deterministic version of the problem can be formulated as a large-scale set covering problem. Several heuristic algorithms are proposed to generate decision policies for the stochastic optimization model over a long rolling horizon. The resulting policies have been extensively tested on instances which display the main characteristics of the industrial case-study that motivated the research. The tests demonstrate the benefits of the multi-period stochastic model over simple myopic strategies. A simple and efficient heuristic is shown to deliver good policies and to be robust against errors in the estimation of the probability distribution of the release dates. [less ▲]

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See detailComparison and impact of waste heat recovery technologies on passenger car fuel consumption on a normalized driving cycle
Legros, Arnaud ULg; Guillaume, Ludovic ULg; Diny, Mouad et al

in Energies (2014)

The purpose of this article was to compare different waste heat recovery system technologies designed for automotive applications. A complete literature review is done and results in two comparative ... [more ▼]

The purpose of this article was to compare different waste heat recovery system technologies designed for automotive applications. A complete literature review is done and results in two comparative graphs. In the second part, simulation models are built and calibrated in order to assess the fuel consumption reduction that can be achieved on a real driving cycle. The strength of this article is that the models are calibrated using actual data. Finally, those simulations results are analyzed and the Rankine cycle and turbocompound are the two most profitable solutions. However the simulations of the turbocompound shows its limitations because the impact on the exhaust pressure drop is not taken into account in the assessment of the car fuel consumption. Fuel reduction of up to 6% could be achieved, depending on the driving cycle and the waste heat recovery technology. [less ▲]

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See detailScalar triplet flavored leptogenesis: a systematic approach
Aristizabal Sierra, Diego ULg; Dhen, Mikael; Hambye, Thomas

in Journal of Cosmology and Astroparticle Physics [= JCAP] (2014), 2014

Type-II seesaw is a simple scenario in which Majorana neutrino masses are generated by the exchange of a heavy scalar electroweak triplet. When endowed with additional heavy fields, such as right-handed ... [more ▼]

Type-II seesaw is a simple scenario in which Majorana neutrino masses are generated by the exchange of a heavy scalar electroweak triplet. When endowed with additional heavy fields, such as right-handed neutrinos or extra triplets, it also provides a compelling framework for baryogenesis via leptogenesis. We derive in this context the full network of Boltzmann equations for studying leptogenesis in the flavored regime. To this end we determine the relations which hold among the chemical potentials of the various particle species in the thermal bath. This takes into account the standard model Yukawa interactions of both leptons and quarks as well as sphaleron processes which, depending on the temperature, may be classified as faster or slower than the Universe Hubble expansion. We find that when leptogenesis is enabled by the presence of an extra triplet, lepton flavor effects allow the production of the B-L asymmetry through lepton number conserving CP asymmetries. This scenario becomes dominant as soon as the triplets couple more to leptons than to standard model scalar doublets. In this case, the way the B-L asymmetry is created through flavor effects is novel: instead of invoking the effect of L-violating inverse decays faster than the Hubble rate, it involves the effect of L-violating inverse decays slower than the Hubble rate. We also analyze the more general situation where lepton number violating CP asymmetries are present and actively participate in the generation of the B-L asymmetry, pointing out that as long as L-violating triplet decays are still in thermal equilibrium when the triplet gauge scattering processes decouple, flavor effects can be striking, allowing to avoid all washout suppression effects from seesaw interactions. In this case the amount of B-L asymmetry produced is limited only by a universal gauge suppression effect, which nevertheless goes away for large triplet decay rates. [less ▲]

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See detailA Remark on the Poroelastic Center of Dilation
Huynen, Alexandre ULg; Detournay, Emmanuel

in Journal of Elasticity (2014), 116(2), 189-206

In the original derivation due to Dougall (1897), the center of dilation is constructed from the superposition of orthogonal force dipoles. However, it can also be built by combining dislocation dipoles ... [more ▼]

In the original derivation due to Dougall (1897), the center of dilation is constructed from the superposition of orthogonal force dipoles. However, it can also be built by combining dislocation dipoles. While the two representations are equivalent in elasticity, the different nature of the force and dislocation dipoles leads to different transient behaviors in poroelasticity, when the response evolves from undrained to drained. Indeed, we show that the poroelastic solution of a center of dilation is obtained by superposing the corresponding elastic solution and either an instantaneous fluid sink or an instantaneous fluid source, depending on whether the center of dilation is treated as a singular stress or displacement discontinuity. A simple explanation to the instantaneous injection or withdrawal of a finite volume of fluid from/to the singularity is given by adopting an exploded view of the poroelastic center of dilation. The exploration of the drained, undrained and transient responses of this singularity also requires to clarify the close relationship between an instantaneous fluid source and a continuous fluid dodecapole, an object constructed by collapsing onto a point three orthogonal pairs of fluid dipoles. [less ▲]

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See detailWASP-104b and WASP-106b: two transiting hot Jupiters in 1.75-day and 9.3-day orbits
Smith, A. M. S.; Anderson, D. R.; Armstrong, D. J. et al

E-print/Working paper (2014)

We report the discovery from the WASP survey of two exoplanetary systems, each consisting of a Jupiter-sized planet transiting an 11th magnitude (V) main-sequence star. WASP-104b orbits its star in 1.75 d ... [more ▼]

We report the discovery from the WASP survey of two exoplanetary systems, each consisting of a Jupiter-sized planet transiting an 11th magnitude (V) main-sequence star. WASP-104b orbits its star in 1.75 d, whereas WASP-106b has the fourth-longest orbital period of any planet discovered by means of transits observed from the ground, orbiting every 9.29 d. Each planet is more massive than Jupiter (WASP-104b has a mass of 1.27±0.05 MJup, while WASP-106b has a mass of 1.93±0.08 MJup). Both planets are just slightly larger than Jupiter, with radii of 1.14±0.04 and 1.09±0.04 RJup for WASP-104 and WASP-106 respectively. No significant orbital eccentricity is detected in either system, and while this is not surprising in the case of the short-period WASP-104b, it is interesting in the case of WASP-106b, because many otherwise similar planets are known to have eccentric orbits. [less ▲]

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See detailTechniques et savoir-faire des artisans de tranchées
Peters, Arnaud ULg

in Créer avant de mourir. Des œuvres d'art dans les tranchées, 1914-1918 (2014)

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See detailDetection of wheat root and straw in soil by use of NIR hyperspectral imaging spectroscopy and Partial Least Square discriminant analysis
Eylenbosch, Damien ULg; Fernández Pierna, Juan Antonio; Baeten, Vincent et al

in Szilvássy, Zoltán; Pepó, Péter; Csajbók, József (Eds.) Book of Abstracts, ESA XIIIth Congress : ESA, Debrecen 25-29 August 2014 (2014, August)

Monitoring of root systems development and crop residues decomposition is only possible if these constituents can be discriminated from soil and quantified. In this work, Near Infrared (NIR) combined with ... [more ▼]

Monitoring of root systems development and crop residues decomposition is only possible if these constituents can be discriminated from soil and quantified. In this work, Near Infrared (NIR) combined with Hyperspectral Imaging (HSI) and Partial Least Square Discriminant Analysis (PLS-DA) is proposed as a new rapid and reliable method to discriminate soil, roots and straws. NIR-HSI provides simultaneously spectral and spatial information and PLS-DA allows discrimination between classes based on spectra of each pixel linked to chemical nature of sample constituents on the image. [less ▲]

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See detailEnhancement of ray tracing method for radiative heat transfer: application to EUI space instrument
Jacques, Lionel ULg; Masset, Luc ULg; Kerschen, Gaëtan ULg

in Proceedings of the 15th International Heat Transfer Conference, IHTC-15 (2014, August)

The finite element method (FEM) is widely used in mechanical engineering, in particular for space structure design. However, FEM is not yet often used for thermal engineering of space structures where the ... [more ▼]

The finite element method (FEM) is widely used in mechanical engineering, in particular for space structure design. However, FEM is not yet often used for thermal engineering of space structures where the lumped parameter method is still dominant. Radiative exchange factors (REFs), used to calculate radiative thermal exchanges in space, are usually computed through Monte Carlo ray tracing. Due to the large number of elements composing a FE model, the computation of the REFs is prohibitively expensive. The isocell method aims at reducing the computational effort of the REFs with FEM, by decreasing the number of rays required to achieve a given accuracy. Based on Nusselt’s analogy, the ray direction sampling is carried out by sampling the unit disc to derive the ray directions. The isocell method is a special case of stratified sampling. It divides the unit disc into cells of almost same area and shape from which random points are generated. This enhances the uniformity of the ray directions and leads to faster convergence. This isocell method is associated with different surface sampling to derive the REFs. The method is benchmarked against ESARAD, the standard thermal analysis ray tracing engine used in the European aerospace industry. One entrance baffle of the Extreme Ultraviolet Imager (EUI) instrument developedat the Centre Spatial de Liège in Belgium is used as benchmarking case. Solar Orbiter is an European Space Agency mission to be launched in a Sun-centered 0.28 perihelion orbit. [less ▲]

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See detailThe role of segmentation and investor recognition through the lens of cross-listing activity
Mouchette, Xavier ULg; Muller, Aline ULg; Carrieri, Francesca

Conference (2014, August)

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See detailThe Semiotic Challenge of Scientific Images. A Test Case for Visual Meaning
Dondero, Maria Giulia ULg; Fontanille, Jacques; Tabler, Julie

Book published by Legas Publishing (2014)

This book is intended to answer the question "What role and impact do images have in scientific research?". In these pages, scientific images are explored as experimental devices (in laboratories), as ... [more ▼]

This book is intended to answer the question "What role and impact do images have in scientific research?". In these pages, scientific images are explored as experimental devices (in laboratories), as instruments of proof (in mathematical logic), as argumentation (in dissemination literature), and in their interactions with other fields, like art and aesthetics. Epistemologists and language scientists will find methodologies that can be used to study the relation between images and knowledge; and scientific imaging experts will find their visualization practices being questioned in all their unique aspects. [less ▲]

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See detailHow to correctly determine the kinetics of a photocatalytic degradation reaction?
Pirard, Sophie ULg; Malengreaux, Charline ULg; Toye, Dominique ULg et al

in Chemical Engineering Journal (2014), 249

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See detailHow Does Your Formulation of Lesion-Induced States of Diminished Consciousness Fit with AIM? Do You Suppose That Brain Stem Damage Affects Activation (A) and Modulation (M)?
Charland-Verville, Vanessa ULg; Laureys, Steven ULg

in J. Allan Hobson, Nicholas Tranquillo (Ed.) Dream Consciousness: A New Approach to the Brain and Its Mind (2014)

Allan Hobson’s AIM model (Hobson, 1998) is build according to three main dimensions. The first component, Activation, describes brain’s activation processes and is closely linked to the level of ... [more ▼]

Allan Hobson’s AIM model (Hobson, 1998) is build according to three main dimensions. The first component, Activation, describes brain’s activation processes and is closely linked to the level of consciousness. According to the model, the brain is highly active in wakefulness and REM sleep but will show much less activity during NREM sleep. The second component, Input/output gateway, controls the inhibition of external stimuli. When slowly falling asleep, the gateway shuts down and inhibits the external stimuli; the brain is no longer involved in processing external perceptions. Then the brain starts its oniric phase and the focus switches to internal inputs. Finally, the third dimension, Modulation, refers to the different ways of cognitive processing (executive functions), judgment, volition and memory. According to the model, those cognitive processes are lacking in REM sleep (i.e., the brain cannot keep a record of its conscious experience during dreaming as opposed to waking state) because of the changes between the aminergic system (norepinephrine and serotonin; dominant in waking but ineffective in REM sleep) and the cholinergic system (acetylcholine; unfettered in REM sleep). These three dimensions maintain a dynamic and reciprocal interaction over the sleep-wake cycle’s variations (wakefulness, NREM and REM sleep) and each of them can be expressed with lower or higher intensities depending on the level of consciousness. [less ▲]

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See detailA quantitative analysis of the effect of flexible loads on reserve markets
Mathieu, Sébastien ULg; Louveaux, Quentin ULg; Ernst, Damien ULg et al

in Proceedings of the 18th Power Systems Computation Conference (PSCC) (2014, August)

We propose and analyze a day-ahead reserve market model that handles bids from flexible loads. This pool market model takes into account the fact that a load modulation in one direction must usually be ... [more ▼]

We propose and analyze a day-ahead reserve market model that handles bids from flexible loads. This pool market model takes into account the fact that a load modulation in one direction must usually be compensated later by a modulation of the same magnitude in the opposite direction. Our analysis takes into account the gaming possibilities of producers and retailers, controlling load flexibility, in the day-ahead energy and reserve markets, and in imbalance settlement. This analysis is carried out by an agent-based approach where, for every round, each actor uses linear programs to maximize its profit according to forecasts of the prices. The procurement of a reserve is assumed to be determined, for each period, as a fixed percentage of the total consumption cleared in the energy market for the same period. The results show that the provision of reserves by flexible loads has a negligible impact on the energy market prices but markedly decreases the cost of reserve procurement. However, as the rate of flexible loads increases, the system operator has to rely more and more on non-contracted reserves, which may cancel out the benefits made in the procurement of reserves. [less ▲]

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See detailMise en réseau des acteurs, des activités et des produits touristiques dans les chefferies de l’Ouest -Cameroun
Lekane Tsobgou, Dieudonné ULg; Schmitz, Serge ULg

in Bokwa, Anita (Ed.) Changes, Challenges, Responsability. IGU 2014 Book of Abstracts (2014, August)

Cette recherche propose comme défis a relever, d’élaborer des dispositifs, des outils et la méthodologie de mise en réseau dans le secteur du tourisme dans les Chefferies de l'Ouest du Cameroun. La ... [more ▼]

Cette recherche propose comme défis a relever, d’élaborer des dispositifs, des outils et la méthodologie de mise en réseau dans le secteur du tourisme dans les Chefferies de l'Ouest du Cameroun. La communication discute des logiques (construit processuel) de la mise en réseau d’acteurs, d’activités et de ressources territoriales dans un circuit touristique [less ▲]

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See detailPhytosanitary treatment of European pallets by microwave: developing a program to ensure compliance with ISPM 15 and monitoring its efficacy on the house longhorn beetle (Hylotrupes bajulus L.)
Henin, Jean-Marc; Leyman, Michael; Bauduin, Aline et al

in European Journal of Wood and Wood Products (2014)

Microwave heating was recently approved by the FAO as a significantly effective phytosanitary treatment for wood packaging material. According to ISPM 15 (FAO 2009), the target organisms are eradicated if ... [more ▼]

Microwave heating was recently approved by the FAO as a significantly effective phytosanitary treatment for wood packaging material. According to ISPM 15 (FAO 2009), the target organisms are eradicated if a temperature higher than 60 °C is maintained for 60 s across the entire profile of the board (i.e. 60 °C/60 s). A study using pallet boards was carried out in order to set up a treatment program that would meet ISPM 15 requirements in terms of wood temperature and insect mortality. A 4 m-long industrial tunnel oven (maximum power of 28.8 kW) was used to carry out the experiments. Temperature was measured by means of a VarioCAM® infrared camera. The most relevant results we found were: (i) achieving a temperature of 63.2 °C (Populus sp.) or 64.8 °C (Pinus sylvestris L.) on the upper surface of 22 mm-thick boards enabled compliance with FAO requirements (i.e. 60 °C/60 s), whatever the moisture content, basic density and initial temperature of the wood (provided the latter exceeded 0 °C); (ii) larvae >150 mg represented the most microwave-resistant life stage of Hylotrupes bajulus L.; (iii) the mortality rate of the larvae was influenced by the moisture content of the boards. Using the Gompertz model, we estimated the upper surface temperature that would be needed to achieve a 99.99683% mortality rate (the Probit 9 mortality level of efficacy) for the most microwave-resistant life stage of H. bajulus. This temperature was estimated to be 46.8 °C and 57 °C for wood with >50 and <25% moisture content, respectively. [less ▲]

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