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See detailModelling the mortality of Hylotrupes bajulus (L.) larvae exposed to anoxic treatment for disinfestation of wooden art objects
de Streel, Géraud; Henin, Jean-Marc; Bogaert, Patrick et al

Conference (2016, September 13)

Experiments were conducted to quantify the effect of several variables on the mortality of insects exposed to an anoxic treatment in order to generate a model linking mortality to these variables. This ... [more ▼]

Experiments were conducted to quantify the effect of several variables on the mortality of insects exposed to an anoxic treatment in order to generate a model linking mortality to these variables. This study aims to explore the possible interest of using such a model to determine the characteristics of treatment (especially duration) needed to guarantee insect mortality with a given level of probability. Trials were performed on Hylotrupes bajulus larvae, which is a widespread species known for its high tolerance to anoxic conditions. The studied variables are the initial mass of the larvae, the treatment temperature (21, 30 and 40 °C), the treatment duration (four durations for each temperature tested) and whether the larva is held in wood or in a petri dish (directly exposed to anoxic atmosphere) during the experiment. It was found that, while the last variable is not correlated with mortality, treatment duration and temperature are significantly and positively correlated with it. Larvae with higher body mass were also shown to have a better resistance to the treatment. Based on these results, a model including insect initial mass, treatment temperature and duration, together with the interaction between these two variables, was determined. This relatively simple model appeared to be a useful tool in overcoming the difficulty in defining the modalities for anoxic treatment in order to reach a given level of mortality. [less ▲]

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See detailModelling the Neritosphere
Djenidi, Salim ULg; Nihoul, Jacques ULg

in Sanchez-Arcilla, A.; Pastor, M.; Zienkiewicz, O. C. (Eds.) et al Proceedings of the 2nd International Conference on Computer Modelling in Ocean Engineering (1991)

Detailed reference viewed: 7 (0 ULg)
See detailModelling the North Sea hydrodynamics in a management perspective
Djenidi, Salim ULg; Delhez, Eric ULg; Martin, Géraldine ULg et al

in Bulletin de la Société Royale des Sciences de Liège (1996), 65

Detailed reference viewed: 16 (5 ULg)
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See detailModelling the Phenomenon of Galloping in Overhead Lines
Lilien, Jean-Louis ULg; Ponthot, Jean-Philippe ULg

in Revue de la Société Royale Belge des Electriciens (1987), 103(12), 5-19

Detailed reference viewed: 52 (10 ULg)
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See detailModelling the plastic anisotropy of metals
Habraken, Anne ULg

in Archives of Computational Methods in Engineering (2004), 11

This work is an overview of available constitutive laws used in finite element codes to model elastoplastic metal anisotropy behaviour at a macroscopic level. It focuses on models with strong links with ... [more ▼]

This work is an overview of available constitutive laws used in finite element codes to model elastoplastic metal anisotropy behaviour at a macroscopic level. It focuses on models with strong links with the phenomena occurring at microscopic level. Starting from macroscopic well-known models such as Hill or Barlat’s laws, the limits of these macroscopic phenomenological yield loci are defined, which helps to understand the current trends to develop micro-macro laws. The characteristics of micro-macro laws, where physical behaviour at the level of grains and crystals are taken into account to provide an average macroscopic answer are described. Some basic knowledge about crystal plasticity models is given for non-specialists, so every one can understand the microscopic models used to reach macroscopic values. The assumptions defining the transition between the microscopic and macroscopic scales are summarized: full constraint or relaxed Taylor’s model, self-consistent approach, homogenisation technique. Then, the two generic families of micromacro models are presented: macroscopic laws without yield locus where computations on discrete set of crystals provide the macroscopic material behaviour and macroscopic laws with macroscopic yield locus defined by microscopic computations. The models proposed by Anand, Dawson, Miehe, Geers, Kalidindi or Nakamachi belong to the first family when proposals by Montheillet, Lequeu, Darrieulat, Arminjon, Van Houtte, Habraken enter the second family. The characteristics of all these models are presented and commented. This paper enhances interests of each model and suggests possible future developments. [less ▲]

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See detailModelling the Position Control of a Segment of the E-ELT using OOFELIE::Multiphysics Integrated FEM-based Approach
Nachtergaele, Philippe; Gamonal Rozas, Leonardo Alfredo ULg; Bruls, Olivier ULg

in Proceedings of the 13th International Conference on New Actuators (2012, June)

This paper presents the extension of a multiphysics software solution allowing to perform integrated simulation of multiphysics controlled systems. This enhancement relies on an innovative formulation of ... [more ▼]

This paper presents the extension of a multiphysics software solution allowing to perform integrated simulation of multiphysics controlled systems. This enhancement relies on an innovative formulation of time integration schemes allowing to take into account simultaneously, in an integrated FEM-based approach, the non linear structural response of a system and the controller dynamics. Interest and feasibility of this unified approach is illustrated through the Modelling of the position control of a segment of the primary mirror of the E-ELT (European Extremely Large Telescope), a highly representative application of complex multiphysics controlled systems. [less ▲]

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See detailModelling the potential of focal screening and treatment as elimination strategy for Plasmodium falciparum malaria in the Peruvian Amazon Region
Rosas-Aguirre, Angel; Erhart, Annette; Llanos-Cuentas, Alejandro et al

in Parasites & Vectors (2015), 8(1), 261

BACKGROUND:Focal screening and treatment (FSAT) of malaria infections has recently been introduced in Peru to overcome the inherent limitations of passive case detection (PCD) and further decrease the ... [more ▼]

BACKGROUND:Focal screening and treatment (FSAT) of malaria infections has recently been introduced in Peru to overcome the inherent limitations of passive case detection (PCD) and further decrease the malaria burden. Here, we used a relatively straightforward mathematical model to assess the potential of FSAT as elimination strategy for Plasmodium falciparum malaria in the Peruvian Amazon Region.METHODS:A baseline model was developed to simulate a scenario with seasonal malaria transmission and the effect of PCD and treatment of symptomatic infections on the P. falciparum malaria transmission in a low endemic area of the Peruvian Amazon. The model was then adjusted to simulate intervention scenarios for predicting the long term additional impact of FSAT on P. falciparum malaria prevalence and incidence. Model parameterization was done using data from a cohort study in a rural Amazonian community as well as published transmission parameters from previous studies in similar areas. The effect of FSAT timing and frequency, using either microscopy or a supposed field PCR, was assessed on both predicted incidence and prevalence rates.RESULTS:The intervention model indicated that the addition of FSAT to PCD significantly reduced the predicted P. falciparum incidence and prevalence. The strongest reduction was observed when three consecutive FSAT were implemented at the beginning of the low transmission season, and if malaria diagnosis was done with PCR. Repeated interventions for consecutive years (10 years with microscopy or 5 years with PCR), would allow reaching near to zero incidence and prevalence rates.CONCLUSIONS:The addition of FSAT interventions to PCD may enable to reach P. falciparum elimination levels in low endemic areas of the Amazon Region, yet the progression rates to those levels may vary substantially according to the operational criteria used for the intervention. [less ▲]

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See detailModelling the primary production interannual variability in the Ligurian Sea due to meteorological conditions with a 1D hydrodynamic/biological model
Lacroix, Geneviève; Nival, Paul; Djenidi, Salim ULg

in EOS : Transactions, American Geophysical Union (1998), 79

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See detailModelling the propagation pathway of street-traffic noise : practical comparison of German guidelines and real-world measurements
Wetzel, Edgar; Nicolas, Jacques ULg; Andre, Philippe ULg et al

in Applied Acoustics (1999), 57(2), 97-107

In Germany, several guidelines were developed to model the noise propagation pathway. The study compares the guidelines DIN 18005, RLS-90 and VDI 2714, all of which provide some kind of sound object line ... [more ▼]

In Germany, several guidelines were developed to model the noise propagation pathway. The study compares the guidelines DIN 18005, RLS-90 and VDI 2714, all of which provide some kind of sound object line source suited to model street traffic noise. Differences between those guidelines are explained, and their effect on practical calculations is shown in a real-world situation, National Road N4, in Arlon, Belgium. Calculated results are compared to measurements made on critical points along the road. The paper emphasises the understanding of the inner workings of models. In order to avoid differences in calculated results due to software design methods applied, all calculations are made using one single commercially available simulation program. Additionally, this allows for a test of guideline sensitivity to changes in input parameters. [less ▲]

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See detailModelling the pumping scheme associated with an impervious wall to avoid the groundwater pollution from a landfill
Dassargues, Alain ULg

in Computer Techniques in Environmental Studies IV, ENVIROSOFT 92, Southampton (1992)

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See detailModelling the regulation of immunoglobulin class switching to IgE and IgG in human B cells to reduce animal use
Eljazi, R; Fear, D; Gould, H et al

Report (2015)

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See detailModelling the risk of ecosystem disruption in Europe with a dynamic vegetation model
Dury, Marie ULg; Hambuckers, Alain ULg; Warnant, Pierre et al

Conference (2012, April)

What will be the European ecosystem responses to future climate? With unprecedented speed and extent, the projected climate change might lead to a disruption of terrestrial plants functioning in many ... [more ▼]

What will be the European ecosystem responses to future climate? With unprecedented speed and extent, the projected climate change might lead to a disruption of terrestrial plants functioning in many regions. In the framework of the EcoChange project, transient projections over the 1901-2100 period have been performed with a process-based dynamic vegetation model, CARAIB DVM (Dury et al., 2011, iForest 4: 82, 99). The vegetation model was driven by the outputs of four climate models under the SRES A1B scenario: the ARPEGE/Climate model and three regional climate models (KNMI-RACMO2 , DMI-HIRHAM5 and HC-HadRM3Q0 RCMs) from the European Union project ENSEMBLES. DVMs are appropriate tools to apprehend potential climate change impacts on ecosystems and identify threatened regions over Europe. CARAIB outputs (soil moisture, runoff, net primary productivity, fire, etc.) were used to characterize the ecosystem evolution. To assess consequences on biodiversity, the evolution of 100 natural common European species (47 herbs, 12 shrubs and 41 trees) has been studied year-to-year over the 1901-2100 period. Under the combined effects of projected changes particularly in temperature and precipitations, CARAIB simulates important reductions in the annual soil water content. The species productivities vary strongly from year to year reaching during the driest years values much lower than present-day average productivity. According to CARAIB, a lot of species might go beyond their water tolerance very frequently, particularly after 2050, due to more intense summer droughts. In the northern part of Europe and in the Alps, with reduced temperature variability and positive soil water anomalies, NPP variability tends to decrease. Regions with more severe droughts might also be affected by an increase of the frequency and intensity of wildfires. With this background, the species distributions might be strongly modified. 15% of tree species and 30% of herb and shrub species (respectively 30% and 60% if the CO2 fertilization effect on species is not taken into account) might experience a loss of 30% or more of their current distribution. Proportions of new species appearance at the end of the century were also studied. Southern Europe might suffer important species extinction while the more suitable climate conditions in northern Europe might lead to a gain in species diversity. [less ▲]

Detailed reference viewed: 67 (17 ULg)
See detailModelling the risk of ecosystem disruption in Europe with a dynamic vegetation model
Dury, Marie ULg

Conference (2012, June)

With unprecedented speed and extent, the projected climate change might lead to a disruption of terrestrial plants functioning in many regions. In the framework of the EcoChange project, the process-based ... [more ▼]

With unprecedented speed and extent, the projected climate change might lead to a disruption of terrestrial plants functioning in many regions. In the framework of the EcoChange project, the process-based dynamic vegetation model, CARAIB DVM (Dury et al., 2011, iForest 4, 82-99) was used to assess the transient vegetation response to climate change and identify threatened regions across Europe. The vegetation model was driven over 1951-2100 by the outputs of 4 climate models under different SRES scenarios: the ARPEGE/Climate model and 3 regional climate models from the European Union project ENSEMBLES. European vegetation was studied at the Bioclimatic Affinity groups scale as well as the species scale. The ability of the climate models to reproduce the present-day climate was evaluated comparing the interannual climate variability simulated by the models with the observed climate variability over 1961-1990 (CRU TS 3.0 dataset). Under the combined effects of projected changes particularly in temperature and precipitations, CARAIB simulates important reductions in the annual soil water content which have large impacts notably on net primary productivity and fire risk in the Mediterranean region but also in other parts of Europe. With this background, the species and biome distributions are projected to be strongly modified. Finally a quantitative index combining some CARAIB outputs evaluates the risk of ecosystem disruption in Europe. [less ▲]

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See detailModelling the seasonal cycle of the biological productivity in the Ligurian Sea by means of a 1D interdisciplinary model
Raick, C.; Soetaert, K.; Grégoire, Marilaure ULg

in VLIZ Young Scientists' Day, Brugge, Belgium 5 March 2004: book of abstracts. VLIZ Special Publication, 17 (2004, March 05)

A one-dimensional coupled physical-biogeochemical model has been built to study the pelagic food web of the Ligurian Sea (NW Mediterranean Sea). The physical model is the turbulent closure model (version ... [more ▼]

A one-dimensional coupled physical-biogeochemical model has been built to study the pelagic food web of the Ligurian Sea (NW Mediterranean Sea). The physical model is the turbulent closure model (version 1D) developed at the GeoHydrodynamics and Environmental Laboratory (GHER) of the University of Liège. The ecosystem model contains nineteen state variables describing the carbon and nitrogen cycles of the pelagic food web. Phytoplankton and zooplankton are both divided in three size-based compartments and the model includes an explicit representation of the microbial loop including bacteria, dissolved organic matter, nano-, and micro- zooplankton. The internal carbon/nitrogen ratio is assumed variable for phytoplankton and detritus, and constant for zooplankton and bacteria. Silicate is considered as a potential limiting nutrient of phytoplankton growth. The aggregation model described in Kriest and Evans (2000) is used to evaluate the sinking rate of particulate detritus. The model is forced at the air-sea interface by meteorological data coming from METEO France. The DYFAMED time series data obtained during the year 2000 are used to calibrate and validate the biological model. The comparison of model results within in-situ DYFAMED data shows that although some processes are not represented by the model, such as horizontal and vertical advections, model results are in good agreement with observations and differences observed can be explained with environmental conditions. [less ▲]

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See detailModelling the sediment transport in a Belgian coastal area
Djenidi, Salim ULg

in Vreughdenil, C. B. (Ed.) Mathematical modelling of sediment transport and morphology (Euromech 177 Colloquium) (1984)

Detailed reference viewed: 13 (5 ULg)
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See detailModelling the short-term and long-term aggregate response of multiple loads fed through a sub-transmission network
Van Cutsem, Thierry ULg; Renoy, Quentin; Lefebvre, Daniel

(2006, November)

This paper addresses the problem of representing the aggregate response to voltage changes of a set of loads fed through distribution transformers connected by a subtransmission network. A simple, while ... [more ▼]

This paper addresses the problem of representing the aggregate response to voltage changes of a set of loads fed through distribution transformers connected by a subtransmission network. A simple, while accurate equivalent is proposed. The latter involves standard network components and includes a single internal bus. This equivalent matches both the short-term and the long-term response of the original system, the long-term dynamics coming from the load tap changers that control the distribution voltages. A procedure to identify its parameters from step responses of the unreduced system is detailed. The method is illustrated and validated on a large subtransmission-distribution system of Hydro-Québec. [less ▲]

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See detailModelling the sound transmission through separation walls using a diffusion model
Billon, Alexis ULg; Foy, Cédric; Valeau, Vincent et al

Conference (2007, September)

The diffusion model has been used successfully to evaluate the acoustic behaviour of a system of coupled rooms connected through a coupling aperture. In this paper, an extension of this model is proposed ... [more ▼]

The diffusion model has been used successfully to evaluate the acoustic behaviour of a system of coupled rooms connected through a coupling aperture. In this paper, an extension of this model is proposed to deal with the propagation of sound energy through a partition wall. The diffusion model can be considered as an extension of the statistical theory to none diffuse sound fields. Numerical comparisons with the statistical theory are then carried out. The following parameters are varied: its transmission loss of the separation wall, its surface, the coupled room’s absorption coefficient and the coupled room’s volume. The agreement between the statistical theory and the diffusion model is very good. [less ▲]

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See detailModelling the spatial distribution of endemic Caesalpinioideae in Central Africa, a contribution to the evaluation of actual protected areas in the region
Ndayishimiye, J.; Greve, M.; Stoffelen, P. et al

in International Journal of Biodiversity and Conservation (2012), 4

Detailed reference viewed: 60 (17 ULg)
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See detailModelling the spray drift by a modified Gaussian tilting plume model.
Stainier, Charles; Robaye, Vincent ULg; Schiffers, Bruno ULg et al

in Aspects of Applied Biology (2006), 77(2), 281-287

The increased concern about environmental effect of pesticides use has resulted in abundant research on spray drift. Spray drift modelling has been developed to get a better understanding of the ... [more ▼]

The increased concern about environmental effect of pesticides use has resulted in abundant research on spray drift. Spray drift modelling has been developed to get a better understanding of the parameters involved and better estimation of the off-target spray deposit. Two groups of models have received extensive a.ttention: Random-walk and computational fluid dynamics (CFD) models have been used to predict the effect of: nozzle height, spray pressure, wind speed,... and were v.alidated with wind tunnels trials. Statistical models based on field trials results have been developed to estimate off-target spray deposit for different sprayers in various environmental conditions. A third group, Gaussian dispersion models, have received early attention in spray drift modelling but are not so popular, despite their international success in environmental pollution modelling. The adaptation of such a model to ground spraying is proposed. The nozzle droplet size distribution measured with a Malvern laser particle analyser is used to divide the nozzle output into several size classes. The spray deposit (or footprint) of each diameter class is computed. The summation of these footprints results in the global drift of the nozzle. The methodology is applied to derive the drift of a.flat fan nozzle located in a wind tunnel and the potential of this approach is discussed. [less ▲]

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See detailModelling the thermal efficiency of condensing boilers working in steady-state conditions
Makaire, Danielle ULg; Ngendakumana, Philippe ULg

Scientific conference (2010, May)

The structure of the model is similar to the model of a conventional boiler model with a main counterflow gas-water heat exchanger (HX1), at which a condensing heat exchanger is added (HX2). The case ... [more ▼]

The structure of the model is similar to the model of a conventional boiler model with a main counterflow gas-water heat exchanger (HX1), at which a condensing heat exchanger is added (HX2). The case losses to the ambient is neglected. Prior to the second heat exchanger (HX2), the exhaust gas are converted to equivalent wet air as the wet heat exchanger is simulated by a cooling coil used in air treatment. The model has been validated experimentally on gas- and oil-fired boilers. Calculated thermal efficiencies agree very well with experimental results. [less ▲]

Detailed reference viewed: 151 (10 ULg)