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See detailModelling Shortest Path Decisions Using an Activity-Based Segmentation
Ramaekers, Katrien; Cools, Mario ULg; Reumers, Sofie et al

in Janssens, Gerrit K.; Ramaekers, Katrien; Caris, An (Eds.) ESM '2010 The European Simulation and Modeling Conference (2010)

The aim of this research is to identify the relationship between activity patterns and route choice decisions. The focus is turned to the relationship between the purpose of a trip and whether or not the ... [more ▼]

The aim of this research is to identify the relationship between activity patterns and route choice decisions. The focus is turned to the relationship between the purpose of a trip and whether or not the shortest path is chosen 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 the choice for the shortest path or not and the corresponding activity-travel behaviour a logistic regression model is developed. The results point out that, when analyzing the relationship between the activities of the people and whether or not the shortest path is chosen, there is no significant influence by the activity-based segmentation. However, when the deviation from the shortest path is related to the activities people perform, a significant relationship is found. Furthermore, next to trip-related attributes (trip distance), also socio-demographic variables and geographical differences play an important role. [less ▲]

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See detailModelling soil heterotrophic respiration in an agricultural soil: Model structure and first comparison with experimental data.
Buysse, Pauline ULg; Le Dantec, Valérie; Sagnier, Charlotte et al

Poster (2008, November 17)

Ce travail visait à adapter un modèle de respiration hétérotrophe du sol à un site agricole situé en Hesbaye (Belgique) et cultivé avec une rotation betterave sucrière / blé d’hiver / pomme de terre / blé ... [more ▼]

Ce travail visait à adapter un modèle de respiration hétérotrophe du sol à un site agricole situé en Hesbaye (Belgique) et cultivé avec une rotation betterave sucrière / blé d’hiver / pomme de terre / blé d’hiver. A long terme, ce modèle fera partie intégrante d’un modèle plus important qui décrira la respiration totale du sol et l’évolution du contenu en carbone du sol dans les cultures. Le modèle utilisé dans ce travail est dérivé du modèle Century, possède un pas de temps journalier et couvre une échelle spatiale de l’ordre de l’écosystème. La paramétrisation du modèle a été réalisée sur base d’une recherche bibliographique et de données collectées sur le site Carbo-Europe de Lonzée. Les caractéristiques du sol sont issues d’analyses réalisées sur des sols limoneux, typiques de la région de Hesbaye. Les variables conductrices (variables météorologiques et apports de litière) furent obtenues suite à une campagne de mesures de 4 ans réalisée sur le site expérimental de Lonzée. Les paramètres biochimiques du blé, de la pomme de terre et de la betterave furent tirés de la littérature. Une analyse de sensibilité fut réalisée en vue de classer les différents paramètres par rapport à leur impact sur le taux de respiration et les contenus en carbone de chaque pool. Les paramètres les plus importants étaient ceux contrôlant la réponse à la température, l’apport de litière et les teneurs en lignine et en azote. Des différences d’impact à court et long terme ont aussi été mises en évidence, notamment à cause de la dynamique de stabilisation des pools et des types de résidus de culture. Finalement, cette analyse nous a permis de définir de futures expériences qui seraient nécessaires pour améliorer l’ajustement du modèle sur des données expérimentales. [less ▲]

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See detailModelling sound diffusion in ray tracing programs
Embrechts, Jean-Jacques ULg

in Proceedings of Acustica 2000-TecniAcustica Congress (2000)

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See detailModelling spray drift using a modified air pollution Gaussian tilting plume model
Stainier, Charles; Destain, Marie-France ULg; Schiffers, Bruno ULg et al

Poster (2007)

The objective of this research is to evaluate a Gaussian tilting plume model that takes into account the spray characteristics of agricultural nozzles to predict drift. The application of this type of ... [more ▼]

The objective of this research is to evaluate a Gaussian tilting plume model that takes into account the spray characteristics of agricultural nozzles to predict drift. The application of this type of model has proved to be effective for aerial pollution applications. To be applied successfully to the spray drift, the model has to give accurate predictions of the deposits regarding the spray and material characteristics as well as the weather parameters. To reach this objective, the model parameters must be correctly set based on appropriate theoretical basis and experimental data. Based on wind tunnel measurements, the effect of the most important characteristics of spray droplets from an agricultural nozzle has been modelled using a Gaussian tilting plume approach by discretizing the different droplet classes. Although the theoretical basis of the model is simple, the predicted drift appeared to be in relatively good agreement with the experimental results. The discrepancies could be explained by poor fitting of the dispersion model parameters. Further work is required to optimise the value of the model parameters. [less ▲]

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See detailModelling strategies for microstructures moving in an electric field
Rochus, Véronique ULg; Andreykiv, Andriy; Rixen, Daniel

in International Conference on Computational Methods for Coupled Problems in Science and Engineering (2007)

Detailed reference viewed: 14 (2 ULg)
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See detailModelling surgical cuts, retractions, and resections via Extended Finite Element Method
Vigneron, Lara M.; Verly, Jacques ULg; Warfield, Simon K.

Conference (2004)

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See detailModelling suspended load transport with linear concentration profiles
Khuat Duy, Bruno ULg; Dewals, Benjamin ULg; Archambeau, Pierre ULg et al

in Proceedings of the 8th International Conference on Fluvial Sedimentology (2005)

In numerical simulations, it is always necessary to find an optimum between the simplicity of the model and a good representation of real phenomena. In the field of hydraulic flows simulations, the models ... [more ▼]

In numerical simulations, it is always necessary to find an optimum between the simplicity of the model and a good representation of real phenomena. In the field of hydraulic flows simulations, the models using depth-averaged and moment equations are an interesting compromise between full 3D and simple depth-averaged models. This paper presents the use of a moment equation for suspended load transport. A simple but representative model for the sediment concentration profiles is developed. This original bi-linear concentration profile is compared to the traditional Rouse-profiles and shows a good correspondence despite its great simplicity. Advective and diffusive sediment fluxes are developed analytically and lead to a concise formulation, which is an asset for practical use. A differential equation for the sediment concentration moment is also fully developed, and a special attention is cast to the source term. The finite volume scheme has been chosen to implement the model, because it is particularly well suited for highly advective transport equations, it is conservative and it makes the choice of the upwinding easier. 1D simulations show the capacity of the model to reproduce laboratory experiments described in the literature. [less ▲]

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See detailModelling suspended load with moment equations and linear concentration profiles
Khuat Duy, Bruno ULg; Dewals, Benjamin ULg; Archambeau, Pierre ULg et al

in Raghay, S.; Ouazar, D.; Benkhaldoun, F. (Eds.) Finite volumes for complex applications (2005)

In numerical simulations, it is always necessary to find an optimum between the simplicity of the model and a good representation of real phenomena. In the field of hydraulic flows simulations, the models ... [more ▼]

In numerical simulations, it is always necessary to find an optimum between the simplicity of the model and a good representation of real phenomena. In the field of hydraulic flows simulations, the models using depth-averaged and moment equations are an interesting compromise between full 3D and simple depth-averaged models. This paper presents the use of a moment equation for suspended load transport. A simple but representative model for the sediment concentration profiles is developed. This original bi-linear concentration profile is compared to the traditional Rouse-profiles and shows a good correspondence despite its great simplicity. Advective and diffusive sediment fluxes are developed analytically and lead to a concise formulation, which is an asset for practical use. A differential equation for the sediment concentration moment is also fully developed, and a special attention is cast to the source term. The finite volume scheme has been chosen to implement the model, because it is particularly well suited for highly advective transport equations, it is conservative and it makes the choice of the upwinding easier. 1D simulations show the capacity of the model to reproduce laboratory experiments described in the literature. [less ▲]

Detailed reference viewed: 91 (4 ULg)
See detailModelling system WOLF
Pirotton, Michel ULg; Archambeau, Pierre ULg; Mouzelard, Thibaut et al

Software (2000)

Detailed reference viewed: 45 (11 ULg)
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See detailModelling temporal stability of EPI time series using magnitude images acquired with multi-channel receiver coils.
Hutton, Chloe; Balteau, Evelyne ULg; Lutti, Antoine et al

in PLoS ONE (2012), 7(12), 52075

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See detailModelling the Arterial Wall by Finite Elements
Mosora, F.; Harmant, A.; Hallet, Claude ULg et al

in Archives Internationales de Physiologie, de Biochimie et de Biophysique (1993), 101(3, May-Jun), 185-91

The mechanical behaviour of the arterial wall was determined theoretically utilizing some parameters of blood flow measured in vivo. Continuous experimental measurements of pressure and diameter were ... [more ▼]

The mechanical behaviour of the arterial wall was determined theoretically utilizing some parameters of blood flow measured in vivo. Continuous experimental measurements of pressure and diameter were recorded in anesthetized dogs on the thoracic ascending and midabdominal aorta. The pressure was measured by using a catheter, and the diameter firstly, at the same site, by a plethysmograph with mercury gauge and secondly, by a sonomicrometer with ferroelectric ceramic transducers. The unstressed radius and thickness were measured at the end of each experiment in situ. Considering that the viscous component is not important relatively to the nonlinear component of the elasticity and utilizing several equations for Young modulus calculation (thick and thin wall circular cylindrical tube formulas and Bergel's equation) the following values were obtained for this parameter: 0.6 MPa-2 MPa in midabdominal aorta and 2 MPa-6.5 MPa in thoracic ascending aorta. The behaviour of the aorta wall was modelled considering an elastic law and using the finite element program "Lagamine" working in large deformations. The discretized equilibrium equations are non-linear and a unique axi-symmetric, iso-parametric element of 1 cm in length with 8 knots was used for this bi-dimensional problem. The theoretical estimation of radius vessel, utilizing a constant 5 MPa Young modulus and also a variable one, are in good agreement with the experimental results, showing that this finite element model can be applied to study mechanical properties of the arteries in physiological and pathological conditions. [less ▲]

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See detailModelling the behaviour of radionuclides in the aquatic ecosystem
Smitz, Joseph ULg; Everbecq, Etienne ULg

Scientific conference (1986, September)

The aim of this work is to model the behaviour of radionuclides released in a surface water ecosystem : contamination of water, sediment, food and (finally) fish. The model is applied to the river Meuse ... [more ▼]

The aim of this work is to model the behaviour of radionuclides released in a surface water ecosystem : contamination of water, sediment, food and (finally) fish. The model is applied to the river Meuse, to assess the concentrations of CS-137 in the major compartments of the river ecosystem, due to releases of CS-137 by the nuclear Power Plant SENA, located at Chooz. [less ▲]

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See detailModelling the behaviour of radionuclides in the aquatic ecosystem
Smitz, Joseph ULg; Everbecq, Etienne ULg

Scientific conference (1986, September)

Radionuclides realeased by nuclear plants in surface waters are not simply transported by the water. Other complex phenomena occur : adsorbtion/desorbtion to sediments, sedimentation and accumulation on ... [more ▼]

Radionuclides realeased by nuclear plants in surface waters are not simply transported by the water. Other complex phenomena occur : adsorbtion/desorbtion to sediments, sedimentation and accumulation on river's bed, interaction with interstitial water, and eventually resuspension in the water column. The aim of this work is the description and modelling of the majors processes which govern the contamination of surface waters and sediments by radionuclides to food chain and to man. The model is applied to the river Meuse. The results shows a good aggreement with available field measurements realized during routine surveys. [less ▲]

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See detailModelling the butterfat crystallisation process
Heyen, Georges ULg; Alleman, Xavier; Kalitventzeff, Boris ULg et al

in Computers & Chemical Engineering (1999), 23(Suppl. S), 819-822

Milk fat exhibits seasonal variations in composition and properties which are undesirable for many subsequent applications. Thus techniques are sought to process dairy products in order to achieve a ... [more ▼]

Milk fat exhibits seasonal variations in composition and properties which are undesirable for many subsequent applications. Thus techniques are sought to process dairy products in order to achieve a consistent quality. A brief introduction to milk fat presents its most important particularities, especially composition, seasonal variations, solid fat content, crystalisation and polymorphism. The differential scanning calorimetry (DSC) analysis allows to estimate the solid fat content. Different methods have been developed to estimate more and more precisely the solid fat content which is certainly an important parameter in the description of the textural properties of butterfat. The industrial crystallisation process is modelled on the basis of pilot plant data. That model allows to approach the particular temperature profile in the scraped surface heat exchangers and to give a first explanation of the involved phenomena. [less ▲]

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See detailModelling the Cape Ghir Upwelling Filament
Troupin, Charles ULg

Scientific conference (2008, December 12)

Detailed reference viewed: 5 (0 ULg)
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See detailModelling the cardiovascular system
Shaw, G. M.; Chase, J. G.; Starfinger, C. et al

in Critical Care and Resuscitation : Journal of the Australasian Academy of Critical Care Medicine (2007), 9(3), 264-269

Detailed reference viewed: 12 (1 ULg)