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See detailModelling Transient Air-water Flows in Civil and Environmental Engineering
Kerger, François ULg

Doctoral thesis (2010)

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See detailModelling weathering processes at the catchment scale: The WITCH numerical model
Godderis, Y.; François, Louis ULg; Probst, A. et al

in Geochimica et Cosmochimica Acta (2006), 70(5), 1128-1147

A numerical model of chemical weathering in soil horizons and underlying bedrock (WITCH) has been coupled to a numerical model of water and carbon cycles in forest ecosystems (ASPECTS) to simulate the ... [more ▼]

A numerical model of chemical weathering in soil horizons and underlying bedrock (WITCH) has been coupled to a numerical model of water and carbon cycles in forest ecosystems (ASPECTS) to simulate the concentration of major species within the soil horizons and the stream of the Strengbach granitic watershed, located in the Vosges Mountains (France). For the first time, simulations of solute concentrations in soil layers and in the catchment river have been performed on a seasonal basis. The model is able to reproduce the concentrations of most major species within the soil horizons, as well as catching the first-order seasonal fluctuations of aqueous calcium, magnesium and silica concentrations. However, the WITCH model underestimates concentrations of Mg2+ and silica at the spring of the catchment stream, and significantly underestimates Ca2+ concentration. The deficit in calculated calcium can be compensated for by dissolution of trace apatite disseminated in the bedrock. However, the resulting increased Ca2+ release yields important smectite precipitation in the deepest model layer (in contact with the bedrock) and subsequent removal of large amount of silica and magnesium from solution. In contrast, the model accurately accounts for the concentrations of major species (Ca, Mg and silica) measured in the catchment stream when precipitation of clay minerals is not allowed. The model underestimation of Mg2+ and H4SiO4 concentrations when precipitation of well crystallized smectites is allowed strongly suggests that precipitation of well crystallized clay minerals is overestimated and that more soluble poorly crystallized and amorphous materials may be forming. In agreement with observations on other watersheds draining granitic rocks, this study indicates that highly soluble trace calcic phases control the aqueous calcium budget in the Strengbach watershed. (c) 2005 Elsevier Inc. All rights reserved. [less ▲]

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See detailModelling Young’s modulus on small clear specimens in relation to silvicultural treatment.
Jourez, Benoît ULg; Leclercq, André

Report (1994)

The aim of this research work performed in Task 11 "Modelling Young's modulus on small clear specimens in relation to silvicultural treatments" was the modelling of Young's modulus (MOE) on small clear ... [more ▼]

The aim of this research work performed in Task 11 "Modelling Young's modulus on small clear specimens in relation to silvicultural treatments" was the modelling of Young's modulus (MOE) on small clear specimens of 24 Belgian Norway spruces in relation with the silvicultural treatment. The aim of the research was also to compare Young's modulus on small clear specimens with Young's modulus on commercial size specimens with a view to defining the rate of prediction of wood quality of specimens including the natural timber defects. This work is corresponding to one task among the twelve of a large ECC Project entitled "SilvicuItural control and non destructive assessment of timber quality in plantation grown Spruces and Douglas fir" for which 210 trees have been sampled through 6 different European countries. The experimental raw material comes from the southern and eastern part<; of Belgium and concerns four different kinds of stands characterized by the site productivity class and the thinning intensity. Within each stand, the trees have been sampled in three different social positions classes. The small clear specimens have been marked off with reference to the radial and axial positions inside the 24 trees. On the whole 350 clear wood specimens have been selected and tested by two different laboratories in order to get young's modulus by a non destructive four points flexural method described by the French Standard NF B 51-016. Young's modulus appears to be positively related with specific gravity and negatively related with growth ring width. Stands growing on high productive sites or those submitted to low thinnings and also suppressed trees give rise to a stiffer wood. Among all these factors, only the social position of the tree within the stand influences significantly the Young's modulus values. Nevertheless, a slow growth producing a heavier timber is not always linked with a stiffer wood. Young's modulus differences between juvenile and adult wood vary in connection with the specific gravity class considered. In other words, juvenile wood is stiffer than adult wood when referring to low density classes, but adult wood becomes stiffer than juvenile wood when referring to high density classes. That means that the stiffness of adult wood is more sensitive to changes in specific gravity than the stiffness of juvenile wood. The distribution of Young's modulus in relation with specific gravity shows a higher variability when specific gravity increases. In searching the reasons for a higher Young's modulus variability when specific gravity increases by looking back to the population of clear specimens, we point out a very low slope of grain on some specimens and above all the presence of compression wood on other specimens. When rejecting these defects, then it appears that Young's modulus is more strongly related to specific gravity, thus giving rise to more accurate models. Among all these models, the best one is corresponding to a combination of variables such as specific gravity and growth ring width per sampling level within the tree. The variance analysis of residues of each model has revealed a tree effect always very highly significant. On the opposite, the other factors, as site productivity, thinning intensity and social position of the tree within the stand, have no significant effect on Young's modulus values. That means that inter trees variability is far higher than the other sources of variation (intra tree variability, site productivity variability, thinning intensity variability and social position variability). This also means that the general model established is valid whatever the silvicultural treatment could be. [less ▲]

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See detailModelling zooplankton impacts on sedimentation
Darchambeau, François ULg

Conference (2000, May 28)

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See detailModelling zooplankton impacts on sedimentation
Darchambeau, François ULg; Thys, Isabelle; Leporcq, Bruno et al

Poster (2000, June 05)

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See detailModelling, simulation and control of flexible multibody systems
Bruls, Olivier ULg; Cardona, Alberto; Géradin, Michel ULg

in Arnold, Martin; Schiehlen, Werner (Eds.) Simulation Techniques in Applied Dynamics (2008)

This chapter concerns the dynamic analysis of flexible multibody systems. After a brief review of the inertial frame, the corotational frame and the floating frame approaches, a general simulation ... [more ▼]

This chapter concerns the dynamic analysis of flexible multibody systems. After a brief review of the inertial frame, the corotational frame and the floating frame approaches, a general simulation framework is presented in detail. Based on the finite element concept, the proposed approach allows the coupled analysis of dynamic systems composed of rigid and flexible bodies, kinematic joints and control elements. The text is illustrated with some didactic examples and industrial applications. [less ▲]

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See detailModelling, Simulation and Optimization of a Shipbuilding Workshop
Bair, Frédéric ULg; Langer, Yves; Caprace, Jean-David ULg et al

in COMPIT'2005 -Conference on Computer Applications and Information Technology in the Maritime Industries, Hamburg (2005, May)

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See detailModellnig of the Hydromechanical Coupling for Non Linear Problems: Fully Coupled and Staggered Approaches
Radu, Jean-Pol ULg; Charlier, Robert ULg

in Proc. of the 8th Int. Conf. of the Int. Ass. for Computer Methods and Advances in Geomechanics (1994, May)

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See detailUn modello di curva di ritenzione per terreni argillosi compattati
Della Vecchia, Gabriele; Jommi, Cristina; Dieudonné, Anne-Catherine ULg

Conference (2013)

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See detailIl modello musicale delle chieze nazionali a Roma in epoca barocca: panoramica e nuove prospettive di ricerca
Corswarem, Emilie ULg

in Kubersky-Pirreda, Susanne (Ed.) - (in press)

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See detailModellreduktion und Analyse des metabolen Netzwerks der Zuckeraufnahme in Escherichia coli
Conzelmann, H.; Sauter, T.; Bullinger, Eric ULg et al

Poster (2003)

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See detailModelo de componentes para análise de ligações de madeira com ligadores metálicos
Cachim, Paulo; Franssen, Jean-Marc ULg

Conference (2011, June 07)

Connections are key elements in any structure because the knowledge of their behaviour is fundamental to an appropriate structural modelling since this behaviour can influence the distribution of efforts ... [more ▼]

Connections are key elements in any structure because the knowledge of their behaviour is fundamental to an appropriate structural modelling since this behaviour can influence the distribution of efforts in different structural elements. In the particular case of wood structures, connections are usually considered as completely rigid or hinged, but their actual behaviour is intermediate between these two extreme limits, depending on the geometry of the connection and the type of connector used. For the design of these connections, the methodology proposed by Eurocode 5 is based on plastic limit analysis which allows the determination of load strength of the connection but not the determination of its stiffness. For the determination of stiffness, Eurocode 5 presents just a very simple expression that depends only on the density of the wood and the diameter of connector to characterize the force-displacement behaviour, disregarding for this purpose the geometry of the connection or the angle of force in relation to the grain. The objective of this paper is to present a component model that allows the characterization of the behaviour of dowel type connections. The results obtained with the model were calibrated with experimental results obtained in the litterature. [less ▲]

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See detailModels and Analysis Tools for the Columbus Contamination Environment
De Leuze, Anne; Barbier, Christian ULg

Conference (1991)

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See detailModels and prospects for a sustainable suburban transition.
Marique, Anne-Françoise ULg; Reiter, Sigrid ULg

Conference (2013, July)

This paper addresses the challenges, transformations and conditions of a sustainable suburban transition. Two powerful levers are used: (1) urban form, which is considered in addition to the individual ... [more ▼]

This paper addresses the challenges, transformations and conditions of a sustainable suburban transition. Two powerful levers are used: (1) urban form, which is considered in addition to the individual building scale, and (2) mobility, because sprawl spatially separates activities, resulting in an increase in travel distances and energy used in transportation. Two main indicators (the heating needs of different types of suburban forms and a commute performance index) are developed and discussed. Three scenarios focused on the evolution of the existing building stock are modelled and assessed (the retrofitting of existing neighbourhoods, an increase in the built density and demolition / reconstruction) to answer two main questions: "how to intervene in suburban areas?" and" where to intervene? ". These main results focused on energy efficiency are then studied in a larger framework to highlight the opportunities, limitations, constraints and feasibility of each strategy. Concrete prospects and guidelines for policy makers are finally proposed to operationalize a "sustainable suburban renewal". These findings show that, beyond the traditional polarization of the debates on energy efficiency of our built environment between the “compact city” and the “sprawled city”, a new pragmatic paradigm, focused on the transition of suburban areas by densification, can make suburban areas evolve towards more sustainability. [less ▲]

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See detailModels for assessing the cost-effectiveness of the treatment and prevention of osteoporosis
Zethraeus, N.; Ben Sedrine, Wafa ULg; Caulin, F. et al

in Osteoporosis International (2002), 13(11), 841-857

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See detailModels for Decision Making: From Applications to Mathematics... and Back
Crama, Yves ULg

Conference (2010, March 15)

In this inaugural lecture, I describe some facets of the interplay between mathematics and management science, economics, or engineering, as they come together in operations research models. I intend to ... [more ▼]

In this inaugural lecture, I describe some facets of the interplay between mathematics and management science, economics, or engineering, as they come together in operations research models. I intend to illustrate, in particular, the complex and fruitful process through which fundamental combinatorial models find applications in management science, which in turn foster the development of new and challenging mathematical questions. [less ▲]

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See detailModels of co-production and social economy in service delivery in Europe
Defourny, Jacques ULg

Scientific conference (2011, June 08)

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See detailModels of irrigation system for Pursat basin planning
Ly, Sarann ULg; Someth, Paradis; Men, Nareth

Poster (2007, May 14)

The Mekong River and the Tonle Sap Great Lake in Cambodia have vast floodplain suitable for rice-based farming system. The Tonle Sap Basin, defined as the catchments of the Tonle Sap River at its ... [more ▼]

The Mekong River and the Tonle Sap Great Lake in Cambodia have vast floodplain suitable for rice-based farming system. The Tonle Sap Basin, defined as the catchments of the Tonle Sap River at its confluence with the Mekong River and other 11 main tributaries draining higher ground on all sides of the basin enclosing 44% of Cambodia’s land area. The Pursat River is one of tributaries of the Tonle Sap Great Lake. It originates at Cardamom Mountains and has very good potential for agricultural development. In this paper, we aim at applying three models of irrigation system for basin planning: Chinit (Dam-Reservoir Irrigation), West Baray (Reservoir Irrigation) and Batheay (Shallow Reservoir Irrigation) to Pursat Basin (one of sub-basin of the Tonle Sap Great Lake). Chinit Dam-Reservoir stores water supplied by one of tributaries of Tonle Sap Great Lake, the Chinit River, located in Kampong Thom Province. Spillway is built to pass up inundation and to release water to downstream part. The rest of water in the Dam-Reservoir is distributed to the paddy field by main canal, secondary canals and tertiary canals. This system can be put at the upstream part of the Pursat River, mountainous area. The West Baray Irrigation system is characterized by a reservoir combined with a dike system in the floodplain of the Tonle Sap Great Lake and an irrigation system situated in Siem Reap province. The reservoir is supplied by a tributary of the Tonle Sap Great Lake, the Siem Reap River, in rainy season. The water is distributed to irrigation area in dry season. A small dike system was constructed in the Tonle Sap floodplain for retarding and storing floodwater. The stored floodwater is used as an additional water source for dry season cultivation. This system can be placed at the central plain of the Pursat Basin. Batheay reservoir directly receives floodwater from the Mekong River. It functions as both a reservoir and a paddy field. In wet season, dike around the Batheay reservoir prevents floodwater from entering the reservoir. Rainy season rice is grown inside the reservoir. After harvesting, gates around the reservoir are opened to receive floodwater. The water is stored for cultivating dry season rice outside the reservoir. This system can be put at the downstream part of the Pursat River, floodplain area of Tonle Sap River. [less ▲]

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See detailModels to estimate overall analytical measurements uncertainty: assumptions, comparisons and applications
Rozet, Eric ULg; Rudaz, S.; Marini Djang'Eing'A, Roland ULg et al

in Analytica Chimica Acta (2011), 702

Evaluation of analytical results reliability is of core importance as crucial decisions are taken with them. From the various methodologies to evaluate the fitness of purpose of analytical methods ... [more ▼]

Evaluation of analytical results reliability is of core importance as crucial decisions are taken with them. From the various methodologies to evaluate the fitness of purpose of analytical methods, overall measurement uncertainty estimation is more and more applied. Overall measurement uncertainty allows to combine simultaneously the remaining systematic influences to the random sources of uncertainty and allows assessing the reliability of results generated by analytical methods. However there are various interpretations on how to estimate overall measurement uncertainty, and thus various models for estimating it. Each model together with its assumptions has great impacts on the risks to abusively declare that analytical methods are suitable for their intended purpose. This review paper aims at i) summarizing the various models used to estimate overall measurement uncertainty, ii) provide their pros and cons, iii) review the main areas of application and iv) as a conclusion provide some recommendations when evaluating overall measurement uncertainty. [less ▲]

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See detailModels to predict the combined effects of temperature and relative humidity on Pectobacterium Atrosepticum and Pectobacterium carotovorum subsp. Carotovorum population density and soft rot disease development at the surface of wounded potato tubers
Moh, Augustin; Massart, Sébastien ULg; Lepoivre, Philippe ULg et al

in Journal of Plant Pathology [=JPP] (2012), 94(1), 181-191

The main objectives of this study were to evaluate and model the influence of temperature (10, 15 and 20°C), relative humidity (86, 96 and 100%) and initial concentration of bacterial inoculum (105, 107 ... [more ▼]

The main objectives of this study were to evaluate and model the influence of temperature (10, 15 and 20°C), relative humidity (86, 96 and 100%) and initial concentration of bacterial inoculum (105, 107 et 109 CFU ml-1) on the population density of Pectobacterium atrosepticum (Pba) and Pectobacterium carotovorum subsp. carotovorum (Pcc) which are important potato pathogens in temperate climates, and on the development of soft rot symptoms caused by these bacteria at the surface of wounded potatoes tubers under controlled conditions. Experiments were carried out according to a Box-Behnken experimental design, simplifying prediction of the combined effects of three controlled factors. With both bacterial species, statistical analysis showed a significant effect of temperature, relative humidity and initially applied bacterial concentration on population dynamics and soft rot development at the surface of wounded potato tubers. Multiple regression analyses and the contour plots showed that the temperature is the most important factor, followed by the initially applied bacteria concentration and relative humidity. More than 64% of the variability of the soft rot symptoms observed could be explained by the presence of Pba and Pcc at the level of wounded potato tubers under the combined effect of tested factors. The quadratic polynomial models developed in our research should integrate the heterogeneity of tested bacteria belonging to the same species (which was not evaluated in this preliminary investigation) in further research. [less ▲]

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