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See detailApplication of a damage model to an aluminium alloy
Castagne, Sylvie; Habraken, Anne ULg; Cescotto, Serge ULg

in International Journal of Damage Mechanics (2003), 12(1), 5-30

An energy-based isotropic elastoplastic model coupled to damage is implemented in the finite element code LAGAMINE developed for more than fifteen years in the MSM department. In this model, based on the ... [more ▼]

An energy-based isotropic elastoplastic model coupled to damage is implemented in the finite element code LAGAMINE developed for more than fifteen years in the MSM department. In this model, based on the local approach of ductile fracture, effective stresses associated to damage variables are introduced. The damage law allows a continuous description of crack appearance. After a brief description of the model, its identification and its validation for an aluminum alloy are presented. Finally, the research of a global rupture criterion associated to this model is introduced. [less ▲]

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See detailApplication of a data minig based technique for the evaluation of transmission expansion plans
Druet, Christophe; Vassena, Stefano; Rousseaux, Patricia ULg et al

in Proceedings of the 15th Power System Computation Conference (PSCC) (2005)

This paper describes a methodology for the study of long-term network planning under uncertainties. In this approach the major external uncertainties during the planning horizon are modelled as macro ... [more ▼]

This paper describes a methodology for the study of long-term network planning under uncertainties. In this approach the major external uncertainties during the planning horizon are modelled as macro-scenarios at different future time instants. The random nature of actual operating conditions is taken into account by using a probabilistic model of micro-scenarios based on past statistics. MonteCarlo simulations are used to generate and simulate a specified number of scenarios. Data mining techniques are then applied to the simulations results collected in a database, so as to extract information and to rank scenarios and network reinforcements according to different performance criteria. The paper describes the application of this approach on a real transmission planning problem faced by the Belgian transmission system operator. [less ▲]

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See detailApplication of a data-interpolating variational analysis (DIVA) tool to physical and biogeochemical measurements covering the Black Sea
Joassin; Beckers, Jean-Marie ULg; Boicenco, L. et al

in Climate change in the Black Sea, hypthesis, observations, trends scenarios and mitigation strategy for the ecosystem (2008)

The European project SESAME (Southern European Seas: Assessing and Modelling Ecosystem changes) is dedicated to the assessment of ecological changes in the Mediterranean and Black seas during these last ... [more ▼]

The European project SESAME (Southern European Seas: Assessing and Modelling Ecosystem changes) is dedicated to the assessment of ecological changes in the Mediterranean and Black seas during these last decades. This assessment will be done by combining statistical analysis of available data and the development of a 3D hydrodynamical-biogeochemical model. Data available since 1960 for the Black Sea from the databases MEDAR and NATO have been completed with data provided by SESAME partners. These data sets have been analyzed using DIVA, a geostatistical analysis tool developed by the GHER laboratory of the University of Liège. The DIVA analysis relies on a finite element resolution, taking into account coastlines, sub-basins, and advection by ocean currents. DIVA analysis generates spatially interpolated fields for biogeochemical and physical variables. Outputs consist in sets of analysis as well as error fields, and colorimetric scaled maps related to several depth layers. Biogeochemical variables considered consist in measures of chlorophyll, inorganic nutrients concentration, and phytoplankton abundances; physical variables consist in temperature and salinity. These treatments of the Black sea data sets offer an overview of the global pattern of the Black sea biogeochemical structure, and its evolution through the time periods concerned by the project. The interpolated fields generated by the DIVA tool will be used to validate the outputs of the 3D hydrodynamical-biogeochemical model developed for the north-western shelf of the Black sea in the framework of SESAME. [less ▲]

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See detailApplication of a diffusion model to predict drying kinetics changes under variable conditions: experimental and simulation study
Bennamoun, Lyes ULg; Belhamri, Azeddine; Ali-Mohamed, Adbéraman

in Fluid Dynamics and Materials Processing (2009), 5(2),

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See detailApplication of a High-Order Upwind Finite-Volume Scheme to 2D Cascade Flows Using a Multi-Block Approach
Rogiest, Pascal; Léonard, Olivier ULg; Essers, Jean-André ULg

in Proceedings of the 12th ISABE Conference (1995)

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See detailApplication of a mass consistent flow model to study the CO2 mass balance of forests
Canepa, Elisa; Georgieva, Emilia; Manca, Giovanni et al

in Agricultural and Forest Meteorology (2010), 150(5), 712-723

The reconstruction of the wind field is one of the main issues in the mass conservation approach for calculation of CO2 advection in forest ecosystems and still remains a challenging problem. In the ... [more ▼]

The reconstruction of the wind field is one of the main issues in the mass conservation approach for calculation of CO2 advection in forest ecosystems and still remains a challenging problem. In the current study, we present an advancement of this approach: the use of a mass consistent flow model (WINDS) which takes into account measured wind data and simulates the 3-D flow field, while imposing airmass conservation in the control volume. We apply the WINDS model to alculate half hourly mean total advective flux terms at the CarboEurope-IP site of Renon (Bozen/Bolzano Autonomous Province), in Northern Italy. The data used refer to six time periods of one day representing three different meteorological conditions observed during the ADVEX campaign from April to September 2005. Current results are compared with results obtained in two other studies for the same time periods. One of these studies is based on the mass conservation approach as well, but applies only interpolations to reconstruct the wind field; the other study makes use of tilt correction (sectorwise planar fit method) for the vertical wind component. In the present study, the effect of the wind field reconstruction method on the estimation of the advective fluxes is discussed. The possibility of using reduced input wind data (i.e. number of towers) for WINDS is also investigated. The results suggest that the representativeness of wind tower measurements is of primary importance for estimating CO2 advection terms and their uncertainty in complex terrain. [less ▲]

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See detailApplication of a Mixed Normal Mixture Model for the Estimation of Mastitis-Related Parameters
Detilleux, Johann ULg; Leroy, P. L.

in Journal of Dairy Science (2000), 83(10), 2341-9

The current methodology for estimating genetic parameters for SCC (SCS) does not account for the difference in SCS between healthy cows and cows with an intramammary infection (IMI). We propose a two ... [more ▼]

The current methodology for estimating genetic parameters for SCC (SCS) does not account for the difference in SCS between healthy cows and cows with an intramammary infection (IMI). We propose a two-component finite mixed normal mixture model to estimate IMI prevalence, separate SCS subpopulation means, individual posterior probabilities of IMI, and SCS variance components. The theory is presented and the expectation-conditional maximization algorithm is utilized to compute maximum likelihood estimates. The methodology is illustrated on two simulated data sets based on the current knowledge of SCS parameters. Maximum likelihood estimates of IMI prevalence and SCS subpopulation means were close to simulated values, except for the estimate of IMI prevalence when both subpopulations were almost confounded. Individual posterior probabilities of IMI were always higher among infected than among healthy cows. Error and additive variance components obtained under the mixture model were closer to simulated values than restricted maximum likelihood estimates obtained assuming a homogeneous SCS distribution, especially when subpopulations were completely separated and when mixing proportion was highest. Convergence was linear and rapid when priors were chosen with caution. The advantages of the methodology are demonstrated, and its feasibility for large data sets is discussed. [less ▲]

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See detailApplication of a multi-model approach to account for conceptual model and scenario uncertainties in groundwater modelling
Rojas, Rodriguo; Kahunde, Samalie; Peeters, Luk et al

in Journal of Hydrology (2010), 394(3-4), 416-435

Groundwater models are often used to predict the future behaviour of groundwater systems. These models may vary in complexity from simplified system conceptualizations to more intricate versions. It has ... [more ▼]

Groundwater models are often used to predict the future behaviour of groundwater systems. These models may vary in complexity from simplified system conceptualizations to more intricate versions. It has been recently suggested that uncertainties in model predictions are largely dominated by uncertainties arising from the definition of alternative conceptual models. Different external factors such as climatic conditions or groundwater abstraction policies, on the other hand, may also play an important role. Rojas et al. (2008) proposed a multimodel approach to account for predictive uncertainty arising from forcing data (inputs), parameters and alternative conceptualizations. In this work we extend upon this approach to include uncertainties arising from the definition of alternative future scenarios and we apply the extended methodology to a real aquifer system underlying the Walenbos Nature Reserve area in Belgium. Three alternative conceptual models comprising different levels of geological knowledge are considered. Additionally, three recharge settings (scenarios) are proposed to evaluate recharge uncertainties. A joint estimation of the predictive uncertainty including parameter, conceptual model and scenario uncertainties is estimated for groundwater budget terms. Finally, results obtained using the improved approach are compared with the results obtained from methodologies that include a calibration step and which use a model selection criterion to discriminate between alternative conceptualizations. Results showed that conceptual model and scenario uncertainties significantly contribute to the predictive variance for some budget terms. Besides, conceptual model uncertainties played an important role even for the case when a model was preferred over the others. Predictive distributions showed to be considerably different in shape, central moment and spread among alternative conceptualizations and scenarios analysed. This reaffirms the idea that relying on a single conceptual model driven by a particular scenario, will likely produce bias and under-dispersive estimations of the predictive uncertainty. Multimodel methodologies based on the use of model selection criteria produced ambiguous results. In the frame of a multimodel approach, these inconsistencies are critical and can not be neglected. These results strongly advocate the idea of addressing conceptual model uncertainty in groundwater modelling practice. Additionally, considering alternative future recharge uncertainties will permit to obtain more realistic and, possibly, more reliable estimations of the predictive uncertainty. [less ▲]

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See detailApplication of a new optimization strategy for the separation of tertiary alkaloids extracted from Strychnos usambarensis leaves
Nistor, Iolanda ULg; Cao, Martine ULg; Debrus, Benjamin ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2011), 56

The HPLC separation of six alkaloids extracted from Strychnos usambarensis leaves has been developed and optimized by means of a powerful methodology for modelling chromatographic responses, based on ... [more ▼]

The HPLC separation of six alkaloids extracted from Strychnos usambarensis leaves has been developed and optimized by means of a powerful methodology for modelling chromatographic responses, based on three steps, i.e. design of experiments (DoE), independent component analysis (ICA) and design space (DS). This study was the first application of a new optimization strategy to a complex natural matrix. The compounds separated are the isomers isostrychnopentamine and strychnopentamine, 10-hydroxyusambarine and 11-hydroxyusambarine, also strychnophylline and strychnofoline. Three LC parameters have been optimized using a multifactorial design comprising 29 experiments that includes 2 center point replicates. The parameters were the percentage of organic modifiers used at the beginning of a gradient profile which consisted in different proportions of methanol (MeOH) and acetonitrile (MeCN), the gradient time to reach 70% of organic modifiers starting from the initial percentage and the percentage of MeCN found in the mobile phase. Subsequent to the experimental design application, predictive multilinear models were developed and used in order to provide optimal analytical conditions. The optimum assay conditions were: methanol/acetonitrile-sodium pentane sulfonate (pH 2.2; 7.5 mM) (33.4:66.6, v/v) at a mobile phase flow rate of 1mL/min during a 40.6 minutes gradient time. The initial organic phase contained 3.7% MeCN and 96.3% MeOH. The method showed good agreement between the experimental data and predictive value throughout the studied parameters space. Improvement of the analysis time and optimized separation for the compounds of interest was possible due to the original and powerful tools applied. Finally, this study permitted the acquisition of isomers profiles allowing the identification of the optimal collecting period of Strychnos usambarensis. [less ▲]

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See detailApplication of a new thermo-mechanical model for study of the nuclear waste disposal in clay rocks
Dizier, Arnaud ULg; François, Bertrand; Collin, Frédéric ULg et al

Conference (2010, October 05)

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See detailApplication of a new thermo-mechanical model for the study of the nuclear waste disposal in clay rocks
Dizier, A.; François, B.; Collin, Frédéric ULg et al

Poster (2012, October)

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See detailApplication of a novel oscillatory flow micro-bioreactor to the production of γ-decalactone in a two immiscible liquid phase medium
Reis, N.; Gonçalves, C. N.; Aguedo, Mario ULg et al

in Biotechnology Letters (2006), 28(7), 485-490

A novel micro-bioreactor based on the oscillatory flow technology was applied to the scale-down of the biotechnological production of γ-decalactone. A decrease up to 50% of the time required to obtain the ... [more ▼]

A novel micro-bioreactor based on the oscillatory flow technology was applied to the scale-down of the biotechnological production of γ-decalactone. A decrease up to 50% of the time required to obtain the maximum concentration of the compound was observed, when compared with other scaled-down platforms (stirred tank bioreactor or shake flask). A three-fold increase in γ-decalactone productivity was obtained by increasing oscillatory mixing intensity from Re o ∼482 to Re o ∼1447. This was presumably related to the effective contribution of the reactor geometry to enhanced mass transfer rates between the two immiscible liquid phases involved in the process by increasing the interfacial area. © Springer 2006. [less ▲]

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See detailApplication of a novel oscillatory flow screening micro-reactor to a biotransformation in a two-phase medium
Vicente, A.; Reis, N.; Nobre, C. et al

in Biochemical engineering : frontiers and advances in biotechnology, biological and biomolecular engineering : abstracts”. [S.n. : s.l.] (2005, June)

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See detailApplication of a SEEK filter to a 1D biogeochemical model of the Ligurian Sea: Twin experiments and real in-situ data assimilation
Raick, Caroline ULg; Alvera Azcarate, Aïda ULg; Barth, Alexander ULg et al

in Journal of Marine Systems (2007), 65(1-4), 561-583

The Singular Evolutive Extended Kalman (SEEK) filter has been implemented to assimilate in-situ data in a 1D coupled physical-ecosystem model of the Ligurian Sea. The biogeochemical model describes the ... [more ▼]

The Singular Evolutive Extended Kalman (SEEK) filter has been implemented to assimilate in-situ data in a 1D coupled physical-ecosystem model of the Ligurian Sea. The biogeochemical model describes the partly decoupled nitrogen and carbon cycles of the pelagic food web. The GHER hydrodynamic model (1D version) is used to represent the physical forcings. The data assimilation scheme (SEEK filter) parameterizes the error statistics by means of a set of empirical orthogonal functions (EOFs). Twin experiments are first performed with the aim to choose the suitable experimental protocol (observation and estimation vectors, number of EOFs, frequency of the assimilation,...) and to assess the SEEK filter performances. This protocol is then applied to perform real data assimilation experiments using the DYFAMED data base. By assimilating phytoplankton observations, the method has allowed to improve not only the representation of the phytoplankton community, but also of other variables such as zooplankton and bacteria that evolve with model dynamics and that are not corrected by the data assimilation scheme. The validation of the assimilation method and the improvement of model results are studied by means of suitable error measurements. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailApplication of a sequential data assimilation technique to improve the results of a 1D couled physical-biogeochemical model of the Ligurian Sea
Raick, C.; Soetaert, K.; Grégoire, Marilaure ULg

in VLIZ Young Scientists' Day, Brugge, Belgium 25th February 2005: book of abstracts (2005)

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See detailApplication Of A Simplified Molecular Protocol To Reveal Mixed Infections With Begomoviruses In Cassava
Busogoro, Jp.; Masquellier, L.; Kummert, J. et al

in Journal of Phytopathology (2008), 156(7-8), 452-457

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See detailApplication of a three-dimensional inverse method to the design of a centrifugal compressor impeller
Demeulenaere, Alain; Léonard, Olivier ULg; Van den Braembussche, Rene

in Proceedings of the ASME Turbo Expo 1998 (1998, June)

ASME Paper 98-GT-127

Detailed reference viewed: 33 (1 ULg)