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See detailModeling the hot subdwarf PB 8783 by asteroseismology
Van Grootel, Valérie ULg; Charpinet, Stéphane; Fontaine, Gilles et al

Conference (2013, May)

Detailed reference viewed: 27 (3 ULg)
Peer Reviewed
See detailModeling the hydrodynamics and the ecosystem dynamics of the Bay of Calvi
Lenartz, F.; Alvera Azcarate, Aïda ULg; Beckers, Jean-Marie ULg et al

Poster (2009, November)

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See detailModeling the hygrothermal behavior of biobased construction materials
Dubois, Samuel ULg; Evrard, Arnaud; Lebeau, Frédéric ULg

in Journal of Building Physics (2013)

Materials with high moisture exchange capacity may have a strong impact on indoor climate conditions as well as building energy performance. Crop-based materials, characterized by their high porosity and ... [more ▼]

Materials with high moisture exchange capacity may have a strong impact on indoor climate conditions as well as building energy performance. Crop-based materials, characterized by their high porosity and hygroscopicity, belong to this category. Modeling their hygrothermal behavior accurately is thus particularly relevant for appropriate building design. A COMSOL Multiphysics transient heat air and moisture model is developed in this article to simulate moisture exchange between a lime–hemp concrete block and surrounding air during a Moisture Buffer Value evaluation test. Results are then compared with the validated heat air and moisture software using performance criteria showing a slight preference for both moisture exchanges and latent heat effect characterization. It offers yet additional advantages in terms of flexibility and transparency as well as further evolution potential. [less ▲]

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See detailModeling the hygrothermal response of a prefabricated straw bale panel and assessing its impact on indoor climate
Dubois, Samuel ULg; Evrard, Arnaud; Lebeau, Frédéric ULg

in 2014 ASABE and CSBE/SCGAB Annual International Meeting (2014, July)

Crop-based materials show many qualities in the quest for construction products with low environmental impact in the construction sector. Their ability to exchange moisture with indoor air offers new ... [more ▼]

Crop-based materials show many qualities in the quest for construction products with low environmental impact in the construction sector. Their ability to exchange moisture with indoor air offers new opportunities for improving interior user comfort and eventually buildings energy performance. Modeling their hygrothermal behavior has thus focused much attention, one of the main objectives being to assess more objectively the resulting performance at building scale. The first natural step in this modeling process is to understand the specific dynamics of heat and mass transfer within such materials. The Building Element Heat Air and Moisture (BEHAM) numerical models were designed to accurately predict internal conditions encountered in materials with partial balance equations. This envelope-based approach, however, requires the knowing of the interior and exterior climate conditions prior to the study. Therefore, it forbids any assessment of mutual exchange between the envelope to the indoor air and prevents any serious validation of the overall performance of materials. In response to this problem, the importance of developing whole building hygrothermal model has recently been raised. General scientific computational tools like MATLAB seem particularly adapted to perform this scaling-up, given their high flexibility and tools integration potentialities. In this communication we study a prefabricated straw bale panel subjected to two distinct and simple solicitations in a climatic chamber. A whole building hygrothermal model developed in MATLAB is then validated with the experimental datasets. The evolution of indoor conditions under the different tests is analyzed in details with an assessment of straw bales performance. [less ▲]

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See detailModeling the impact of macroscale and mesoscale hydrodynamics on the space-time distribution of the Black sea’s plankton bloom annual cycle. Comparison of model results with CZCS observations
Grégoire, Marilaure ULg; Nihoul, J.

in Robinson, A.; Lermusiaux, P. (Eds.) Assimilation of biological data in coupled Physical/Ecosystem models (2000)

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See detailModeling the influence of Greenland ice sheet melting on the Atlantic meridional overturning circulation during the next millennia
Driesschaert, E.; Fichefet, T.; Goosse, H. et al

in Geophysical Research Letters (2007), 34(10),

A three-dimensional Earth system model of intermediate complexity including a dynamic ice sheet component has been used to investigate the long-term evolution of the Greenland ice sheet and its effects on ... [more ▼]

A three-dimensional Earth system model of intermediate complexity including a dynamic ice sheet component has been used to investigate the long-term evolution of the Greenland ice sheet and its effects on the Atlantic meridional overturning circulation (AMOC) in response to a range of stabilized anthropogenic forcings. Our results suggest that the Greenland ice sheet volume should experience a significant decrease in the future. For a radiative forcing exceeding 7.5 W m(-2), the modeled ice sheet melts away within 3000 years. A number of feedbacks operate during this deglaciation, implying a strong nonlinear relationship between the radiative forcing and the melting rate. Only in the most extreme scenarios considered, the freshwater flux from Greenland into the surrounding oceans ( of ca. 0.1 Sv during a few centuries) induces a noticeable weakening of the AMOC in the model. [less ▲]

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See detailModeling the influence of oxygen in delayed bone fracture healing.
Carlier, Aurélie ULg; Geris, Liesbet ULg; Van Oosterwyck, Hans

Conference (2013, August 25)

Detailed reference viewed: 15 (4 ULg)
See detailModeling the influence of the Greenland ice sheet melting on the Atlantic meridional overturning circulation during the next millennia
Fichefet, Thierry; Driesschaert, Emmanuelle; Goosse, Hugues et al

Conference (2007, April 19)

A three-dimensional Earth system model of intermediate complexity including a dynamic ice sheet component has been used to investigate the long-term evolution of the Greenland ice sheet and its effects on ... [more ▼]

A three-dimensional Earth system model of intermediate complexity including a dynamic ice sheet component has been used to investigate the long-term evolution of the Greenland ice sheet and its effects on the Atlantic meridional overturning circulation (AMOC) in response to a range of stabilized anthropogenic forcings. Our results suggest that the Greenland ice sheet volume should experience a significant decrease in the future. For a radiative forcing exceeding 7.5 W m-2, the modeled ice sheet melts away within 3000 years. A number of feedbacks operate during this deglaciation, implying a strong non-linear relationship between the radiative forcing and the melting rate. In the most extreme scenario considered, the freshwater flux from Greenland into the surrounding oceans is higher than 0.1 Sv during a few centuries. This is however insufficient to induce a shutdown of the AMOC in the model. [less ▲]

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See detailModeling the instantaneous pressure-volume relationship in the left ventricle
Lucas, Alexandra ULg; Dauby, Pierre ULg; Desaive, Thomas ULg et al

in 9th Belgian Day on Biomedical Engineering, Friday November 26th 2010 in the Academy Palace, Hertogstraat 1, 1000 Brussels (2010, November 26)

Models and simulations are very useful to study interactions between anatomic structures and physical cardiac phenomena. In this work, we are interested in models of the instantaneous pressure-volume ... [more ▼]

Models and simulations are very useful to study interactions between anatomic structures and physical cardiac phenomena. In this work, we are interested in models of the instantaneous pressure-volume relationship, i.e. isochrone models. More precisely, we concentrate on the 6 models considered by Lankhaar et al. [1]. We propose a critical analysis of the work of these authors and suggest some improvement of their procedure. [1] Lankhaar J.-W. et al. Modeling the Instantaneous Pressure–Volume Relation of the Left Ventricle: A Comparison of Six Models. Annals of Biomedical Engineering, Volume 37, Number 9, 1710-1726, 2009. [less ▲]

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See detailModeling the instantaneous pressure-volume relationship in the left ventricle
Lucas, Alexandra ULg; Dauby, Pierre ULg; Kolh, Philippe ULg et al

Poster (2010, November 26)

Pressure-volume loops are a common modeling tool of the cardiovascular system. They are very useful because they characterize the global function of the cardiac pump and can also be analyzed ... [more ▼]

Pressure-volume loops are a common modeling tool of the cardiovascular system. They are very useful because they characterize the global function of the cardiac pump and can also be analyzed by considering the various phases of the cardiac cycle and marking each point of a cycle with the corresponding time. When several loops are considered, the points corresponding to the same time t in each loop can be joined to define a curve named isochrone. In this work, we are interested in models of the instantaneous pressure-volume relationship, i.e. isochrone models. More precisely, we concentrate on the 6 models considered by Lankhaar et al. [1] and we propose a critical analysis of the work of these authors and suggest some improvement of their procedure. [1] Lankhaar J.W. et al. Annals of Biomedical Engineering, Volume 37, Number 9, 1710-1726, 2009. [less ▲]

Detailed reference viewed: 44 (14 ULg)
See detailModeling the Martian ionosphere using the Total Electron Content measurement by the NEIGE/NETLANDER experiment
Morel, Laurent; Witasse, Olivier; Warnant, René ULg et al

in Proceedings of the XXVII URSI General Assembly (2002)

Detailed reference viewed: 15 (3 ULg)
See detailModeling the Martian ionosphere using the Total Electron Content measurement by the NEIGE/NETLANDER experiment
Morel, Laurent; Witasse, Olivier; Warnant, René ULg et al

Poster (2001)

Detailed reference viewed: 8 (0 ULg)
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See detailModeling the mass and surface heat budgets in a coastal blue ice area of Adelie Land, Antarctica
Favier, Vincent; Agosta, Cécile ULg; Genthon, Christophe et al

in Journal of Geophysical Research. Earth Surface (2011), 116

Meteorological data recorded from 12 December 2008 to 30 June 2010 were analyzed to assess the surface energy balance (SEB) in a blue ice area of Cap Prudhomme, Adelie Land (66 degrees 41'S, 139 degrees ... [more ▼]

Meteorological data recorded from 12 December 2008 to 30 June 2010 were analyzed to assess the surface energy balance (SEB) in a blue ice area of Cap Prudhomme, Adelie Land (66 degrees 41'S, 139 degrees 55'E). The SEB was computed with a newly developed model forced by direct measurements and with a voluntarily limited number of parameters to better assess model sensitivity. Incoming short-wave radiation was corrected for the slope and orientation of the local terrain assuming direct and diffuse radiation components. Turbulent heat fluxes were assessed using the bulk aerodynamic approach. Heat conduction in the ice was computed by solving the thermal diffusion equation. Snow accumulation was modeled using ERA interim total precipitation and a one-dimensional erosion model. The surface heat budget and accumulation/erosion model accurately reproduced field observations. The occurrence of blue ice is linked with higher rates of erosion than in the surrounding snow covered areas, which may be caused by local flow divergence or snow not being redistributed from higher elevations. Melting occurs between December and February when incoming short-wave radiation is high. However, the SEB was closely linked to air temperature through the incoming long-wave radiation and the turbulent sensible heat flux. Several warm events caused by cyclones intruding into the continent led to significant warming of the ice and high melting rates. Intruding cyclones were also associated with high precipitation that led to significant accumulation. Except in blue ice areas, modeling suggests that expected higher precipitation in a warmer climate will result in more accumulation. [less ▲]

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See detailModeling the mechanical behavior of concrete in the fire situation
Gernay, Thomas ULg

Scientific conference (2012, April 26)

Detailed reference viewed: 25 (12 ULg)
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See detailModeling the Modulation of Neuronal Bursting: A Singularity Theory Approach
Franci, Alessio ULg; Drion, Guillaume ULg; Sepulchre, Rodolphe ULg

in SIAM Journal on Applied Dynamical Systems (2014), 13(2), 798-829

Exploiting the specific structure of neuron conductance-based models, the paper investigates the mathematical modeling of neuronal bursting modulation. The proposed approach combines singularity theory ... [more ▼]

Exploiting the specific structure of neuron conductance-based models, the paper investigates the mathematical modeling of neuronal bursting modulation. The proposed approach combines singularity theory and geometric singular perturbations to capture the geometry of multiple time-scale attractors in the neighborhood of high-codimension singularities. We detect a three–time-scale bursting attractor in the universal unfolding of the winged cusp singularity and discuss the physiological relevance of the bifurcation and unfolding parameters in determining a physiological modulation of bursting. The results suggest generality and simplicity in the organizing role of the winged cusp singularity for the global dynamics of conductance-based models. [less ▲]

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See detailModeling the morphology and mechanical behavior of shape memory polyurethanes based on solid-state NMR and synchrotron SAXS/WAXD
D'Hollander, Stijn; Gommes, Cédric ULg; Mens, Raoul et al

in Journal of Materials Chemistry (2010), 20

A combination of solid-state proton Wide-line Nuclear Magnetic Resonance (NMR) relaxometry and synchrotron Small-angle (SAXS) and Wide-angle (WAXD) X-ray scattering was used to elucidate the microphase ... [more ▼]

A combination of solid-state proton Wide-line Nuclear Magnetic Resonance (NMR) relaxometry and synchrotron Small-angle (SAXS) and Wide-angle (WAXD) X-ray scattering was used to elucidate the microphase morphology of shape memory thermoplastic multi-block polyurethanes based on poly(3-caprolactone), as switching segment and polyurethane based permanent or hard segments (HS). The polyurethanes are produced from the condensation of 1,4-butanediol (BDO) with hexamethylenediisocyanate (HDI). The morphology – induced by the hard-segment crystallization – converts from dispersed randomly placed hard-segment domains into progressively more periodic, but interconnected HS nanophases with increasing HS content. Irrespective of the actual morphology, the SAXS data could be described satisfactorily by using a clipped Gaussian random field (GRF) model. The NMR data demonstrate that the HS domain fraction corresponds to the chemical feed, pointing at a complete phase separation. The material mechanical behavior during repeated deformation cycles can be explained on morphological grounds and involves a spatially heterogeneous plastic deformation of the hard domains. [less ▲]

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See detailModeling the mutation of socio-ecosystems in Central Africa
Gillet, Pauline ULg; Vermeulen, Cédric ULg

Poster (2013, February)

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See detailModeling the nitrogen cycling and plankton productivity in the Black Sea using a three-dimensional interdisciplinary model
Grégoire, Marilaure ULg; Soetaert, Karline; Nezlin, Nikolay Pavlovich et al

in Journal of Geophysical Research. Oceans (2004), 109(C5),

[1] A six-compartment ecosystem model defined by a simple nitrogen cycle is coupled with a general circulation model in the Black Sea so as to examine the seasonal variability of the ecohydrodynamics ... [more ▼]

[1] A six-compartment ecosystem model defined by a simple nitrogen cycle is coupled with a general circulation model in the Black Sea so as to examine the seasonal variability of the ecohydrodynamics. Model results show that the annual cycle of the biological productivity of the whole basin is characterized by the presence of a winter-early spring bloom. In all the regions this bloom precedes the onset of the seasonal thermocline and occurs as soon as the vertical winter mixing decreases. Phytoplankton development starts in winter in the central basin, while in coastal areas ( except in the river discharge area) it begins in early spring. In the Danube's discharge area and along the western coast, where surface waters are almost continuously enriched in nutrient by river inputs, the phytoplankton development is sustained during the whole year at the surface. The seasonal variability of the northwestern shelf circulation induced by the seasonal variations in the Danube discharge and the wind stress intensity has been found to have a major impact on the primary production repartition of the area. In the central basin the primary production in the surface layer relies essentially on nutrients being entrained in the upper layer from below. Simulated phytoplankton concentrations are compared with satellite and field data. It has been found that the model is able to reproduce the main characteristics of the space-time evolution of the Black Sea's biological productivity but underestimates the phytoplankton biomass especially in regions extremely rich in nutrients such as the Danube discharge area. [less ▲]

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See detailModeling the nitrogen fluxes in the Black Sea using a 3D coupled hydrodynamical-biogeochemical model: transport versus biogeochemical processes, exchanges across the shelf break and comparison of the shelf and deep sea ecodynamics
Grégoire, Marilaure ULg; Beckers, Jean-Marie ULg

in Biogeosciences (2004), 1(1), 33-61

A 6-compartment biogeochemical model of nitrogen cycling and plankton productivity has been coupled with a 3D general circulation model in an enclosed environment (the Black Sea) so as to quantify and ... [more ▼]

A 6-compartment biogeochemical model of nitrogen cycling and plankton productivity has been coupled with a 3D general circulation model in an enclosed environment (the Black Sea) so as to quantify and compare, on a seasonal and annual scale, the typical internal biogeochemical functioning of the shelf and of the deep sea as well as to estimate the nitrogen and water exchanges at the shelf break. Model results indicate that the annual nitrogen net export to the deep sea roughly corresponds to the annual load of nitrogen discharged by the rivers on the shelf. The model estimated vertically integrated gross annual primary production is 130 g C m(-2) yr(-1) for the whole basin, 220 g C m(-2) yr(-1) for the shelf and 40 g C m(-2) yr(-1) for the central basin. In agreement with sediment trap observations, model results indicate a rapid and efficient recycling of particulate organic matter in the sub-oxic portion of the water column (60-80 m) of the open sea. More than 95% of the PON produced in the euphotic layer is recycled in the upper 100 m of the water column, 87% in the upper 80 m and 67% in the euphotic layer. The model estimates the annual export of POC towards the anoxic layer to 4 10(10) mol yr(-1). This POC is definitely lost for the system and represents 2% of the annual primary production of the open sea. [less ▲]

Detailed reference viewed: 60 (11 ULg)