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
See detailModelization of Kirchhoff scattering by a sound ray algorithm
Embrechts, Jean-Jacques ULg

in Proceedings of the 16th International Congress on Acoustics (ICA) and 135th meeting of the Acoustical Soc. of America (ASA) - Volume 4 (1998)

Detailed reference viewed: 24 (7 ULg)
Full Text
See detailModelization of photosynthetic and respiratory maximal activities as a function of culture parameters in Chlamydomonas reinhardtii using design of experiment and data analysis by JMP (SAS Institute)
Gerin, Stéphanie ULg; Mathy, Grégory; Franck, Fabrice ULg

Poster (2013, August)

We aimed to modelize the dependence of photosynthetic as well as cytochromial and alternative respiratory maximal activities upon different culture parameters, i.e. light intensity and acetate, carbon ... [more ▼]

We aimed to modelize the dependence of photosynthetic as well as cytochromial and alternative respiratory maximal activities upon different culture parameters, i.e. light intensity and acetate, carbon dioxide, nitrate and ammonium concentrations, in the model unicellular green alga Chlamydomonas reinhardtii. Culture parameters were submitted to a dedicated statistical software (JMP 10.0, SAS Institute) for the generation of a design of experiment. Measurements of oxygen concentrations were carried out to quantify maximal activities. JMP was further used to detect culture parameters exerting a statistically significant effect on maximal activities and to modelize the dependence of maximal activities upon these culture parameters of interest. [less ▲]

Detailed reference viewed: 30 (15 ULg)
See detailModelization, Development and Testing of a Variable Geometry Nozzle
Mignon, Anthony; Léonard, Olivier ULg

in Proceedings of the 5th Belgian National Congress on Theoretical and Applied Mechanics (2000)

Detailed reference viewed: 18 (1 ULg)
Full Text
Peer Reviewed
See detailModelled glacial and non-glacial HCO3-, Si and Ge fluxes since the LGM: little potential for impact on atmospheric CO2 concentrations and a potential proxy of continental chemical erosion, the marine Ge/Si ratio
Jones, Ian W; Munhoven, Guy ULg; Tranter, Martyn et al

in Global and Planetary Change (2002), 33(1-2), 139-153

The runoff and riverine fluxes of HCO3-, Si and Ge that arise from chemical erosion in non-glaciated terrain, are modelled at six time steps from the Last Glacial Maximum (LGM) to the present day. The ... [more ▼]

The runoff and riverine fluxes of HCO3-, Si and Ge that arise from chemical erosion in non-glaciated terrain, are modelled at six time steps from the Last Glacial Maximum (LGM) to the present day. The fluxes that arise from the Great Ice Sheets are also modelled. Terrestrial HCO3- fluxes decrease during deglaciation, largely because of the reduction in the area of the continental shelves as sea level rises. The HCO3- fluxes. and the inferred consumption of atmospheric CO2 are used as inputs to a carbon cycle model that estimates their impact on atmospheric CO2 concentrations ((CO2)-C-atms). A maximum perturbation of (CO2)-C-atms by similar to 5.5 ppm is calculated, The impact of solutes from glaciated terrain is small in comparison to those from non-glaciated terrain. Little variation in terrestrial Si and Ge fluxes is calculated (< 10%). However, the global average riverine Ge/Si ratio may be significantly perturbed if the glacial Ge/Si ratio is high. At present. variations in terrestrial chemical erosion appear to have only a reduced impact on (CO2)-C-atms and only little influence on the global Si and Ge cycle and marine Ge/Si ratios during deglaciation. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

Detailed reference viewed: 4 (0 ULg)
Full Text
Peer Reviewed
See detailModellierung des Trennverhaltens wässriger Systeme in Packungskolonnen basierend auf tomographischen
Janzen, Anna; Steube, Julia; Aferka, Saïd ULg et al

Conference (2012, March)

Detailed reference viewed: 24 (5 ULg)
Full Text
Peer Reviewed
See detailModelling a high-mass red giant observed by CoRoT
Baudin, F.; Barban, C.; Goupil, M. J. et al

in Astronomy and Astrophysics (2012), 538

Context. The advent of space-borne photometers such as CoRoT and Kepler has opened up new fields in asteroseismology. This is especially true for red giants as only a few of these stars were known to ... [more ▼]

Context. The advent of space-borne photometers such as CoRoT and Kepler has opened up new fields in asteroseismology. This is especially true for red giants as only a few of these stars were known to oscillate with small amplitude, solar-like oscillations before the launch of CoRoT. <BR /> Aims: The G6 giant HR 2582 (HD 50890) was observed by CoRoT for approximately 55 days. We present here the analysis of its light curve and the characterisation of the star using different observables, such as its location in the Hertzsprung-Russell diagram and seismic observables. <BR /> Methods: Mode frequencies are extracted from the observed Fourier spectrum of the light curve. Numerical stellar models are then computed to determine the characteristics of the star (mass, age, etc.) from the comparison with observational constraints. <BR /> Results: We provide evidence for the presence of solar-like oscillations at low frequency, between 10 and 20 μHz, with a regular spacing of (1.7 ± 0.1) μHz between consecutive radial orders. Only radial modes are clearly visible. From the models compatible with the observational constraints used here, We find that HR 2582 (HD 50890) is a massive star with a mass in the range (3-5 M[SUB]&sun;[/SUB]), clearly above the red clump. It oscillates with rather low radial order (n = 5-12) modes. Its evolutionary stage cannot be determined with precision: the star could be on the ascending red giant branch (hydrogen shell burning) with an age of approximately 155 Myr or in a later phase (helium burning). In order to obtain a reasonable helium amount, the metallicity of the star must be quite subsolar. Our best models are obtained with a mixing length significantly smaller than that obtained for the Sun with the same physical description (except overshoot). The amount of core overshoot during the main-sequence phase is found to be mild, of the order of 0.1 H[SUB]p[/SUB]. <BR /> Conclusions: HR 2582 (HD 50890) is an interesting case as only a few massive stars can be observed due to their rapid evolution compared to less massive red giants. HR 2582 (HD 50890) is also one of the few cases that can be used to validate the scaling relations for massive red giants stars and its sensitivity to the physics of the star. The CoRoT space mission, launched on 2006 December 27, was developed and is operated by the CNES with participation of the Science Programs of ESA; ESA's RSSD, Austria, Belgium, Brazil, Germany and Spain. [less ▲]

Detailed reference viewed: 6 (0 ULg)
Peer Reviewed
See detailModelling agricultural strategies to protect groundwater resources in the Hesbaye aquifer (Belgium)
Sohier, Catherine ULg; Degré, Aurore ULg

in Fraters, Dico; Kovar, Karel (Eds.) International Interdisciplinary Conference on Land Use and Water Quality, Reducing Effects of Agriculture, The Hague, the Netherlands, 10-13 June 2013 (2013)

Groundwater quality is spoiled by various substances resulting from human activities. In addition to pesticides, one of the most problematic substances is nitrate. Pumping prevention areas are strategic ... [more ▼]

Groundwater quality is spoiled by various substances resulting from human activities. In addition to pesticides, one of the most problematic substances is nitrate. Pumping prevention areas are strategic zones in terms of struggle against diffuse pollution by nitrate. In order to reduce diffuse pollution of waters by nitrate, different strategies of agricultural practices can be implemented. Their impact can be evaluated either by monitoring water quality or using an agro-hydrological model. The advantage of modelling is to be able to test long term impacts of implemented measures and impacts of complementary measures. Using EPICgrid distributed agro-hydrological model, we reproduced the current agricultural practices. We calculated nitrate leaching but also the nitrate stock in the root zone. These results were validated through a comparison with a lot of nitrogen stock measurements. (These measurements are compulsory in the Walloon context.) The nitrate concentration in pumping wells was also used to assess the efficiency of the model. After this calibration phase, we modelled several scenarios of more water-protective agricultural practices. Indeed, the Hesbaye galleries represent an important source of drinking water in the Walloon region, it is therefore highly probable that further mitigation measures are going to be imposed in the pumping prevention area. An increase in the area cultivated with cereals, a strong limitation of mineral fertilisation as well as a conversion to grasslands were tested and combined. The results of these simulations show how some agricultural practices scenarios can lead to an important decrease in diffuse pollution by nitrate. Prospective simulations taking into account possible future climate evolution (global change scenarios) are carried out to assess nitrate concentrations near the groundwater table for the deadlines of the WFD (2015, 2021 and 2027). Due to the transfer time through the vadose zone (more than 20 years in some subregions), it is showed that an increase in groundwater nitrate concentrations will occur, in some areas, until at least 2030 before new agricultural practices can impact positively the groundwater quality. [less ▲]

Detailed reference viewed: 3 (0 ULg)
Full Text
See detailModelling and optimization of an hydrogeological system to prevent groundwater pollution from a leaky landfill
Dassargues, Alain ULg

in Int. Symp. on Environmental Contamination, Budapest (1992)

Detailed reference viewed: 15 (4 ULg)
Peer Reviewed
See detailModelling and parameter estimation for heterogeneous cell populations
Waldherr, S; Hasenauer, J; Schliemann, Monica ULg et al

Poster (2009)

Detailed reference viewed: 13 (0 ULg)
Full Text
See detailThe modelling and simulation of ocean's circulation on supercomputers
Beckers, Jean-Marie ULg

in Melli, P.; Zannetti, P. (Eds.) Environmental Modelling (1992)

Detailed reference viewed: 7 (3 ULg)
Peer Reviewed
See detailModelling and Simulation of Rat Swimming in a Water Maze Experiment
Fey, D.; Commins, Séan; Bullinger, Eric ULg

Poster (2009)

Detailed reference viewed: 5 (0 ULg)
Full Text
See detailA modelling approach as an intermediate step for the study of protection zones in karstified limestones
Dassargues, Alain ULg; Derouane, Johan

in Leibundgut, Christian; Gunn, John; Dassargues, Alain (Eds.) Karst Hydrology (Proc. of Rabat Workshop W2) (1998)

Detailed reference viewed: 13 (1 ULg)
Full Text
See detailA modelling approach of the Ross Sea plankton ecosystem
Hecq, Jean-Henri ULg; Guglielmo, Lillo; Goffart, Anne ULg et al

in Faranda, F.; Guglielmo, L.; Ianora, A. (Eds.) Ross Sea Ecology - ITALIANTARTIDE Expeditions (1987-1995) (1999)

See pdf file in attachment

Detailed reference viewed: 8 (3 ULg)
Full Text
Peer Reviewed
See detailModelling argon dynamics in first-year sea ice
Moreau, S.; Vancoppenolle, M; Zhou, Jiayun ULg et al

in Ocean Modelling (2014), 73

Abstract: Focusing on physical processes, we aim at constraining the dynamics of argon (Ar), a biogeochemically inert gas, within first year sea ice, using observation data and a one-dimensional halo ... [more ▼]

Abstract: Focusing on physical processes, we aim at constraining the dynamics of argon (Ar), a biogeochemically inert gas, within first year sea ice, using observation data and a one-dimensional halo-thermodynamic sea ice model, including parameterization of gas physics. The incorporation and transport of dissolved Ar within sea ice and its rejection via gas-enriched brine drainage to the ocean, are modeled following fluid transport equations through sea ice. Gas bubbles nucleate within sea ice when Ar is above saturation and when the total partial pressure of all three major atmospheric gases (N2, O2 and Ar) is above the brine hydrostatic pressure. The uplift of gas bubbles due to buoyancy is allowed when the brine network is connected with a brine volume above a given threshold. Ice-atmosphere Ar fluxes are formulated as a diffusive process proportional to the differential partial pressure of Ar between brine inclusions and the atmosphere. Two simulations corresponding to two case studies that took place at Point Barrow (Alaska, 2009) and during an ice-tank experiment (INTERICE IV, Hamburg, Germany, 2009) are presented. Basal entrapment and vertical transport due to brine motion enable a qualitatively sound representation of the vertical profile of the total Ar (i.e. the Ar dissolved in brine inclusions and contained in gas bubbles; TAr). Sensitivity analyses suggest that gas bubble nucleation and rise are of most importance to describe gas dynamics within sea ice. Ice-atmosphere Ar fluxes and the associated parameters do not drastically change the simulated TAr. Ar dynamics are dominated by uptake, transport by brine dynamics and bubble nucleation in winter and early spring; and by an intense and rapid release of gas bubbles to the atmosphere in spring. Important physical processes driving gas dynamics in sea ice are identified, pointing to the need for further field and experimental studies. [less ▲]

Detailed reference viewed: 24 (4 ULg)
Peer Reviewed
See detailModelling at the biological/biomechanical interface: fracture healing case studies
Geris, Liesbet ULg

in Exploring the biological/biomechanics interface (2009)

Detailed reference viewed: 7 (1 ULg)
Full Text
Peer Reviewed
See detailModelling atmospheric CO2 changes at geological timescales
François, Louis ULg; Grard, Aline ULg; Goddéris, Yves

in Carnets de Géologie = Notebooks on Geology (2005), M02/02(Memoir 2005/02), 11-14

Detailed reference viewed: 8 (2 ULg)
Full Text
See detailModelling autotrophic and heterotrophic components of soil respiration in wheat fields
Delogu, Emilie; LeDantec, Valérie; Buysse, Pauline ULg et al

Conference (2012, April)

Detailed reference viewed: 16 (5 ULg)
Full Text
See detailModelling Bark Thickness in the tree in relation to silviculturaltreatment
Jourez, Benoît ULg; Leclercq, André

Report (1993)

Based upon a sampling of 186 trees of Norway spruce, Sitka spruce and Douglas fir from Belgium (24 Norway spruce), Denmark (24 Norway spruce and 24 Sitka spruce), France (24 Norway spruce), Germany (24 ... [more ▼]

Based upon a sampling of 186 trees of Norway spruce, Sitka spruce and Douglas fir from Belgium (24 Norway spruce), Denmark (24 Norway spruce and 24 Sitka spruce), France (24 Norway spruce), Germany (24 Douglas fir), Great Britain (24 Sitka spruce) and Italy (24 Douglas fir) specially cut for the Project, this study which is a part (Task 6) of a larger ECC Project, has shown the effects of the tree, its Social position in the stand, the thinning intensity and the site productivity on bark thickness and bark volume. All along the stem, bark thickness has a particular profile characterized by a steep decrease from the bottom up to a given height variable from species to species, due to a bottom effect, then being relatively constant up to the living crown base level and finally decreasing slightly in the living crown part. The most important bottom effect has been observed on Douglas fir. Referring to a variance components analysis, variability in bark thickness is mainly due to the tree itself and the stand factor which globalized the cumulated effect of thinning intensity and site productivity. However, it appears that the trees selected by couple for each Social position in each stand are similar whatever the species could be, and may be considered, in fact, as true replicates. For each species, the Social position of the tree in the stand influences bark thickness in the same way. In all cases, dominant trees have indeed the thickest bark, whilst suppressed trees are always characterized by the thinnest bark and co-dominant trees range to this respect in an intermediate position. The effect of site productivity is not clear through this sampling, due to interferences of different factors, mainly the differences in tree age which let appear a significant effect of the country (differences in growing conditions and between productivity classes). Nevertheless, when tree age is almost the same in different countries, the general trends are going in the direction of a decrease of bark thickness when the site productivity becomes lower. The same general trends are observed in connection with the thinning intensity because bark thickness generally decreases when thinnings are less intense. In fact, bark thickness is far to be constant according to the stand selection criteria (site productivity, thinning intensity) but is noticeably affected by the tree selection criteria (Social position). Bark thickness, bark volume and amount of bark are mainly depending on the growing conditions with a major effect of the Social position compared to the thinning intensity and the site productivity. Unfortunately, a general model was unsuitable for an accurate prediction of bark thickness. The best predicted values of bark thickness was obtained in using common models, linear ones for Norway spruce and Sitka spruce but non linear ones for Douglas fir. [less ▲]

Detailed reference viewed: 17 (2 ULg)
Full Text
Peer Reviewed
See detailModelling BSE trend over time in europe, a risk assessment perspective
Ducrot, C.; Sala, C.; Ru, G. et al

in European Journal of Epidemiology (2010)

Detailed reference viewed: 10 (3 ULg)
Full Text
Peer Reviewed
See detailModelling chemical weathering at river catchment scale: design and calibration of the WiTCh model
Probst, A.; Godderis, Y.; François, Louis ULg et al

in Geochimica et Cosmochimica Acta (2002), 66(15A), 615-615

Detailed reference viewed: 12 (0 ULg)