Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
See detailModeling of Weakly Conducting Thin Sheets in the Discontinuous Galerkin Method for Shielding Effectiveness Evaluation
Boubekeur, Mohamed; Kameni, Abelin; Modave, Axel ULg et al

in ACES Journal (2013), 28(10), 931

This paper presents a modeling of weakly conducting thin sheets in the time domain discontinuous Galerkin method. This interface condition is used to avoid the mesh of resistive sheets in order to ... [more ▼]

This paper presents a modeling of weakly conducting thin sheets in the time domain discontinuous Galerkin method. This interface condition is used to avoid the mesh of resistive sheets in order to evaluate the shielding effectiveness in high frequency electromagnetic compatibility problems. This condition is valid when the thickness of the sheet is smaller than the skin depth. This approach is validated by a comparison with an analytical solution. A 1D two sheets example, 2D and 3D cavities are treated to illustrate the efficiency of the condition. [less ▲]

Detailed reference viewed: 19 (7 ULg)
Full Text
See detailModeling Operational Risk Based on Multiple Experts’ Opinion
Peters, Jean-Philippe; Hübner, Georges ULg

in Gregoriou, Greg (Ed.) Operational Risk Towards Basel III (2009)

While the Basel II accord has now gone live in most parts of the world, many discrepancies still remain on advanced modeling techniques for operational risk among large international banks. The two major ... [more ▼]

While the Basel II accord has now gone live in most parts of the world, many discrepancies still remain on advanced modeling techniques for operational risk among large international banks. The two major families of models include the loss distribution approaches (LDAs) that focus on observed past internal and external loss events and the scenario-based techniques that use subjective opinions from experts as the starting point to determine the regulatory capital charge to cover operational risk. A major methodological challenge is the combination of both techniques so as to fulfill Basel II requirements. In this chapter we discuss and investigate the use of various alternatives to model expert opinion in a sound statistical way so as to allow for subsequent integration with loss distributions fitted on internal and/or external data. A numerical example supports the analysis and shows that solutions exist to merge information arising from both sources. [less ▲]

Detailed reference viewed: 84 (8 ULg)
Full Text
Peer Reviewed
See detailModeling p-18FMPPF pet kinetics for the detremination of local 5-HT1A receptor concentration.
Costes, N.; Le Bars, D.; Merlet, I. et al

in Journal of Nuclear Medicine : Official Publication, Society of Nuclear Medicine (2001), 42(S1), 209

Detailed reference viewed: 7 (0 ULg)
Full Text
See detailModeling post-combustion CO2 capture with amine solvents
Léonard, Grégoire ULg; Heyen, Georges ULg

Poster (2011, June)

Carbon capture and storage is a technology that can contribute to face the challenge of rising energy demand combined with a growing environmental awareness. In the present work, the CO2 capture process ... [more ▼]

Carbon capture and storage is a technology that can contribute to face the challenge of rising energy demand combined with a growing environmental awareness. In the present work, the CO2 capture process with monoethanolamine (MEA) is modeled using the simulation tool Aspen Plus. Two different modeling approaches are studied and compared: the equilibrium and the rate-based approaches. An optimization of key process parameters is performed and process modifications are studied with the objective of improving the global process energy efficiency. [less ▲]

Detailed reference viewed: 14 (0 ULg)
Full Text
Peer Reviewed
See detailModeling post-combustion CO2 capture with amine solvents
Léonard, Grégoire ULg; Heyen, Georges ULg

Conference (2010)

Oral communication at the Cape-forum, Aachen, 2010. Modeling CO2 capture process and optimization of some process parameters with an equilibrium-based model.

Detailed reference viewed: 39 (6 ULg)
Full Text
Peer Reviewed
See detailModeling post-combustion CO2 capture with amine solvents
Léonard, Grégoire ULg; Heyen, Georges ULg

in Computer Aided Chemical Engineering (2011), 29

Carbon capture and storage is a technology that can contribute to face the challenge of rising energy demand combined with a growing environmental awareness. In the present work, the CO2 capture process ... [more ▼]

Carbon capture and storage is a technology that can contribute to face the challenge of rising energy demand combined with a growing environmental awareness. In the present work, the CO2 capture process with monoethanolamine (MEA) is modeled using the simulation tool Aspen Plus. Two different modeling approaches are studied and compared: the equilibrium and the rate-based approaches. An optimization of key process parameters is performed and process modifications are studied with the objective of improving the global process energy efficiency. [less ▲]

Detailed reference viewed: 124 (30 ULg)
Full Text
Peer Reviewed
See detailModeling post-combustion CO2 capture with amine solvents
Léonard, Grégoire ULg; Heyen, Georges ULg

Poster (2010)

In order to avoid the emission of large amounts of greenhouse gas, CO2 capture in fossil fuel power plants and subsequent underground CO2 sequestration is studied. The capture occurs by reactive CO2 ... [more ▼]

In order to avoid the emission of large amounts of greenhouse gas, CO2 capture in fossil fuel power plants and subsequent underground CO2 sequestration is studied. The capture occurs by reactive CO2 absorption into chemical solvent systems at moderate temperature (~50°C) followed by solvent regeneration at higher temperature (~120°C). So far, the most employed solvent for acid gas capture is monoethanolamine (MEA). One main drawback of this technology is the high energy consumption necessary to regenerate the solvent. In the present work, the CO2 capture process with MEA is modeled using the simulation tool Aspen Plus®. The base case process is optimized and some process improvements are studied that imply a significant decrease of the process exergy consumption. [less ▲]

Detailed reference viewed: 53 (7 ULg)
Full Text
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 ▲]

Detailed reference viewed: 32 (5 ULg)
Full Text
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 ▲]

Detailed reference viewed: 9 (3 ULg)
Full Text
Peer Reviewed
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)

Detailed reference viewed: 17 (1 ULg)
Full Text
Peer Reviewed
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),

Detailed reference viewed: 116 (80 ULg)
Full Text
Peer Reviewed
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)

Detailed reference viewed: 45 (17 ULg)
Full Text
See detailModeling risk and expected returns in finance and macroeconomics
Lejeune, Thomas ULg

Doctoral thesis (2014)

This doctoral dissertation contributes to the modeling of risk and expected returns in the fields of finance and macroeconomics. On the finance side, the thesis proposes a portfolio choice model and a ... [more ▼]

This doctoral dissertation contributes to the modeling of risk and expected returns in the fields of finance and macroeconomics. On the finance side, the thesis proposes a portfolio choice model and a risk-return setup that simultaneously deal with agents’ unknown utility function, incomplete knowledge of financial return distributions, departures from the Gaussian distribution (i.e. asymmetry and fat-tail risks), investment horizons and investors’ objectives in terms of expected returns. On the macroeconomic side, the objective is to deliver a comprehensive picture of the financial sector in a general equilibrium framework, which accommodates the heterogeneity of behaviors within financial intermediaries. The first part of the thesis introduces an innovative risk measure, risk horizon, with reference to the speed of convergence of an asset’s mean return to its expectation. This measure is a keystone to a general framework for characterizing investors’ behavior in portfolio selection, which takes into account consideration for volatility, asymmetric and fat-tail risk, a trade-off between downside and upside potential of financial assets, and the timing and probability of deviations from expected returns. The risk horizon framework opens up the way to the identification of forward-looking determinants of market sentiment that includes, among others, the expected market and credit returns. The last part of the thesis is devoted to a macroeconomic model with heterogeneous and financially constrained intermediaries. An analysis of endogenous risk mechanisms when traditional and shadow banking interact is carried out. The model sheds light on the importance of relative leverage behaviors in the amplification of adverse shocks in the economy. [less ▲]

Detailed reference viewed: 11 (4 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 16 (0 ULg)
Peer Reviewed
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)

Detailed reference viewed: 24 (3 ULg)
Full Text
Peer Reviewed
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

Detailed reference viewed: 23 (11 ULg)
Full Text
See detailModeling soil respiration in wheat fields
Delogu, Emilie; Le Dantec, Valérie; Mordelet, Patrick et al

Poster (2013, April 09)

Detailed reference viewed: 40 (0 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 27 (6 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 32 (3 ULg)