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See detailModeling post-combustion CO2 capture with assessment of solvent degradation
Léonard, Grégoire ULg; Belletante, Ségolène; Cabeza Mogador, Bruno et al

Conference (2013, October)

Post-combustion CO2 capture in power plants is one of the most mature technologies for a short-term and large-scale decrease of CO2 emissions while simultaneously addressing the growing global energy ... [more ▼]

Post-combustion CO2 capture in power plants is one of the most mature technologies for a short-term and large-scale decrease of CO2 emissions while simultaneously addressing the growing global energy demand. CO2 is chemically absorbed in an amine solvent that can be regenerated at higher temperature, producing a pure CO2 stream. However, the large impact of this technology on the power plant efficiency and the environmental penalty are the main drawbacks for large-scale implementation. In this work, an innovative approach combining process modeling and evaluation of the environmental penalty due to amine degradation is presented. Based on experimental results, the kinetics of solvent oxidative and thermal degradation is estimated and included in the process model developed in Aspen Plus. Using this model, the influence of operating parameters like the oxygen concentration in the flue gas or the solvent regeneration pressure is studied. This model is a first step for a multi-objective optimization of the CO2 capture process, assessing both energy and environmental penalties of this technology. [less ▲]

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See detailModeling pulsations in hot stars with winds
Noels-Grötsch, Arlette ULg; Dupret, Marc-Antoine ULg; Godart, Mélanie ULg

in Journal of Physics: Conference Series (2008), 118

The interaction pulsation/mass loss takes different aspects. Pulsations can trigger mass loss as in LBVs and Miras; on the other hand, mass loss can modify the driving conditions within the stars. But the ... [more ▼]

The interaction pulsation/mass loss takes different aspects. Pulsations can trigger mass loss as in LBVs and Miras; on the other hand, mass loss can modify the driving conditions within the stars. But the most spectacular aspect is the effect on stellar models which, in turn, opens a royal way to asteroseismology to test physical conditions inside massive stars, such as the extent of convective cores or the appearance of new driving mechanisms. We start with a discussion on MS stars and their strange mode instabilities. We then move on to the excitation of the LBV phenomenon. WR stars and the newly observed MOST period in WR123 are discussed in view of the power of asteroseismology. We then turn to B supergiants, in particular HD163899, and show how asteroseismology can really probe convection, semiconvection and mass loss. [less ▲]

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See detailModeling reaction-limited Ostwald ripening of supported Ni catalysts in presence of CO: the role of particle size distribution
Gommes, Cédric ULg; Munnik, Peter; de Jongh, Petra et al

Poster (2014, March)

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See detailModeling recent bark stripping by red deer (Cervus elaphus) in South Belgium coniferous stands
Ligot, Gauthier ULg; Gheysen, Thibaut; Lehaire, François ULg et al

in Annals of Forest Science : a Multidisciplinary and International Journal (2013), 70(3),

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See detailMODELING RELATIONSHIPS BETWEEN JUMP HEIGHT, GROUND CONTACT TIME, REACTIVITY AND STIFFNESS
Jidovtseff, Boris ULg; Apolloni, Jérémy; Harris, Nigel et al

in Abstract book of 8th International Conference on Strength Training (2012, October)

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See detailModeling Route Choice of Car Travelers using an Activity-Based Segmentation
Cools, Mario ULg; Ramaekers, Katrien; Reumers, Sofie et al

in Proceedings of the 90th Annual Meeting of the Transportation Research Board (DVD-ROM) (2011)

The aim of this research is to identify the relationships between activity patterns and route choice decisions. The focus is turned to the relationship between the purpose of a trip and the road ... [more ▼]

The aim of this research is to identify the relationships between activity patterns and route choice decisions. The focus is turned to the relationship between the purpose of a trip and the road categories used for the relocation. The data for this study were collected in 2006 and 2007 in Flanders, the Dutch speaking and northern part of Belgium. To estimate the relationship between he primary road category traveled on and the corresponding activity-travel behavior a multinomial logit model is developed. The results point out that route choice is a function of multiple factors, not just travel time or distance. Crucial for modeling route choices or in general for traffic assignment procedures is the conclusion that activity patterns have a clear influence on the road category primarily driven on. Particularly, it was shown that the likelihood of taking primarily through roads is highest for work trips and lowest for leisure trips. This certainly suggests that traffic assignment procedures should be developed that explicitly take into account an activity-based segmentation. In addition, it was shown that route choices were similar during peak and off-peak periods. This is an indication that car drivers are not necessarily utility maximizers. A potential pathway for further investigating route choice decisions might lie in the roots of more psychological underpinnings. [less ▲]

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See detailModeling simple lipid phase separation and effects of amphiphilic molecules on lipid domains
Lins, Laurence ULg; Deleu, Magali ULg; Mingeot-Leclercq, Marie-Paule et al

Poster (2013, April 28)

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See detailModeling soil heterotrophic respiration with an enzyme-based model: first comparison with field data and suggestions of improvements
Buysse, Pauline ULg; Longdoz, Bernard; Debacq, Alain ULg et al

in Geophysical Research Abstracts (2011, April 07), 13

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See detailModeling soil respiration in wheat fields
Delogu, Emilie; Le Dantec, Valérie; Mordelet, Patrick et al

Poster (2013, April 09)

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See detailModeling Species Distributions from Heterogeneous Data for the Biogeographic Regionalization of the European Bryophyte Flora
Mateo, R. G. A; Vanderpoorten, Alain ULg; Muñoz, J. B D et al

in PLoS ONE (2013), 8(2),

The definition of biogeographic regions provides a fundamental framework for a range of basic and applied questions in biogeography, evolutionary biology, systematics and conservation. Previous research ... [more ▼]

The definition of biogeographic regions provides a fundamental framework for a range of basic and applied questions in biogeography, evolutionary biology, systematics and conservation. Previous research suggested that environmental forcing results in highly congruent regionalization patterns across taxa, but that the size and number of regions depends on the dispersal ability of the taxa considered. We produced a biogeographic regionalization of European bryophytes and hypothesized that (1) regions defined for bryophytes would differ from those defined for other taxa due to the highly specific eco-physiology of the group and (2) their high dispersal ability would result in the resolution of few, large regions. Species distributions were recorded using 10,000 km2 MGRS pixels. Because of the lack of data across large portions of the area, species distribution models employing macroclimatic variables as predictors were used to determine the potential composition of empty pixels. K-means clustering analyses of the pixels based on their potential species composition were employed to define biogeographic regions. The optimal number of regions was determined by v-fold cross-validation and Moran's I statistic. The spatial congruence of the regions identified from their potential bryophyte assemblages with large-scale vegetation patterns is at odds with our primary hypothesis. This reinforces the notion that post-glacial migration patterns might have been much more similar in bryophytes and vascular plants than previously thought. The substantially lower optimal number of clusters and the absence of nested patterns within the main biogeographic regions, as compared to identical analyses in vascular plants, support our second hypothesis. The modelling approach implemented here is, however, based on many assumptions that are discussed but can only be tested when additional data on species distributions become available, highlighting the substantial importance of developing integrated mapping projects for all taxa in key biogeographically areas of Europe, and the Mediterranean peninsulas in particular. © 2013 Mateo et al. [less ▲]

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See detailModeling Stationary and Evolving Discontinuities with Finite Elements
Moës, Nicolas; Béchet, Eric ULg

in Owen, D. R. J.; Onate, E. (Eds.) VII International Conference on Computational Plasticity COMPLAS 2003 (2003)

A methodology for treating non-planar three-dimensional cracks with geometries that are independent of the mesh is summarized. The method is based on the extended finite element method, in which the crack ... [more ▼]

A methodology for treating non-planar three-dimensional cracks with geometries that are independent of the mesh is summarized. The method is based on the extended finite element method, in which the crack discontinuity is introduced as a Heaviside step function via a partition of unity. In addition, branch functions are introduced for all elements containing the crack front. The crack geometry is described by two signed distance functions (level sets), which in turn can be defined by nodal values. Consequently, no explicit representation of the crack is needed. A Hamilton-Jacobi equation is used to update the level sets as the crack grows. Numerical experiments show the robustness of the method in treating cracks with significant changes in topology. The method is readily extendable to inelastic fracture problems. [less ▲]

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See detailModeling stochastic excitation of acoustic modes in stars: present status and perspectives
Samadi, R.; Belkacem, Kevin ULg; Goupil, M*-J et al

in Communications in Asteroseismology (2008), 157

Solar-like oscillations have now been detected for more than ten years and their frequencies measured for a still growing number of stars with various characteristics (e.g. mass, chemical composition ... [more ▼]

Solar-like oscillations have now been detected for more than ten years and their frequencies measured for a still growing number of stars with various characteristics (e.g. mass, chemical composition, evolutionary stage ...). Excitation of such oscillations is attributed to turbu- lent convection and takes place in the uppermost part of the convective envelope. Since the pioneering work of Goldreich & Keely (1977), more sophisticated theoretical models of stochastic excitation were developed, which differ from each other both by the way turbulent convection is modeled and by the assumed sources of excitation. We briefly review here the different underlying approximations and assumptions of those models. A second part shows that computed mode excitation rates crucially depend on the way time-correlations between eddies are described but also on the surface metal abundance of the star. [less ▲]

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See detailModeling the black grouse population : a tool for management.
Loneux, Michèle ULg; Lindsey, J.; Poncin, Pascal ULg

Conference (2007)

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See detailModeling the Black Sea and the Mediterranean Sea hydrodynamics: a comparative study
Beckers, Jean-Marie ULg; Elmoussaoui, A.; Rixen, M. et al

in Balopoulos, E.; Chronis, G.; Lipiatou, E. (Eds.) et al International conference. Oceanography of the eastern Mediterranean and Black Sea. Similarities and differences of two interconnected basins, Zappeion international conference Centre (2000)

The application of the GHER 3D primitive equation model to the simulation of the seasonal cycle of the Mediterranean and Black Sea circulation will be shown. The two basins are very illustrative for ... [more ▼]

The application of the GHER 3D primitive equation model to the simulation of the seasonal cycle of the Mediterranean and Black Sea circulation will be shown. The two basins are very illustrative for either concentration or dilution basins, and modelling such different systems needs some special attention with respect to the representation of the water masses and mixing between the different layers. The strength of the variability of both basins will be compared, including comparison with climatological data. Turbulent characteristics in both cases alalysed, showing that at the scales under investigations, both turbulent regimes are close to a balance between production, destruction and vertical diffusion of turbulence. ft is also shown how the river dominaled Black Sea exhibits specific free surface behaviors while the Mediterranean Sea exhibits specific deep water formations leading both to a different kind of vertical mixing. [less ▲]

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See detailModeling the dependence of respiration and photosynthesis upon light, acetate, carbon dioxide, nitrate and ammonium in Chlamydomonas reinhardtii using design of experiments and multiple regression
Gerin, Stéphanie ULg; Mathy, Gregory; Franck, Fabrice ULg

in BMC Systems Biology (2014), 8(96),

Background: In photosynthetic organisms, the influence of light, carbon and inorganic nitrogen sources on the cellular bioenergetics has extensively been studied independently, but little information is ... [more ▼]

Background: In photosynthetic organisms, the influence of light, carbon and inorganic nitrogen sources on the cellular bioenergetics has extensively been studied independently, but little information is available on the cumulative effects of these factors. Here, sequential statistical analyses based on design of experiments (DOE) coupled to standard least squares multiple regression have been undertaken to model the dependence of respiratory and photosynthetic responses (assessed by oxymetric and chlorophyll fluorescence measurements) upon the concomitant modulation of light intensity as well as acetate, CO2, nitrate and ammonium concentrations in the culture medium of Chlamydomonas reinhardtii. The main goals of these analyses were to explain response variability (i.e. bioenergetic plasticity) and to characterize quantitatively the influence of the major explanatory factor(s). Results: For each response, 2 successive rounds of multiple regression coupled to one-way ANOVA F-tests have been undertaken to select the major explanatory factor(s) (1st-round) and mathematically simulate their influence (2nd-round). These analyses reveal that a maximal number of 3 environmental factors over 5 is sufficient to explain most of the response variability, and interestingly highlight quadratic effects and second-order interactions in some cases. In parallel, the predictive ability of the 2nd-round models has also been investigated by k-fold cross-validation and experimental validation tests on new random combinations of factors. These validation procedures tend to indicate that the 2nd-round models can also be used to predict the responses with an inherent deviation quantified by the analytical error of the models. Conclusions: Altogether, the results of the 2 rounds of modeling provide an overview of the bioenergetic adaptations of C. reinhardtii to changing environmental conditions and point out promising tracks for future in-depth investigations of the molecular mechanisms underlying the present observations. [less ▲]

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See detailModeling the dissociation and ionization of a sputtered organic molecule
Solomko, V.; Verstraete, Matthieu ULg; Delcorte, A. et al

in Applied Surface Science (2006), 252

Detailed reference viewed: 19 (5 ULg)