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See detailModelling migration from high-density polyethylene containers into concentrated solutions used as food flavourings
Fauconnier, Marie-Laure ULg; Panhaleux, V.; Vanzeveren, E. et al

in Food Additives & Contaminants (2001), 18(11), 1040-1045

Migration from high-density polyethylene into different liquids (hexane, ethanol, lemon terpenes and their emulsions) was modelled using the response surfaces method. Polynomial equations (z = A + Bx + Cy ... [more ▼]

Migration from high-density polyethylene into different liquids (hexane, ethanol, lemon terpenes and their emulsions) was modelled using the response surfaces method. Polynomial equations (z = A + Bx + Cy + Dx(2) + Ey(2) + Fxy) were established and parameters determined for each compound. Correlation coefficients were generally > 90%. Analysis indicated that 2,4-bis(1,1-dimethylethyl) phenol, probably due to the degradation of the antioxidant additive tris(2,4- bis(1,1-dimethylethyl) phenyl) phosphite, migrated into each liquid tested, whatever the temperature. Oligomers (10-30 carbons) terminated by a vinyl group were also detected. [less ▲]

Detailed reference viewed: 77 (15 ULg)
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See detailModelling Mixed Flows in Civil and Environmental Engineering: a 1D Three-phase Approach
Kerger, François ULg; Archambeau, Pierre ULg; Dewals, Benjamin ULg et al

in Proc of 7th International Conference on Mutiphase Flow (2010)

Detailed reference viewed: 29 (4 ULg)
Peer Reviewed
See detailModelling nitrogen fluxes in a semi-enclosed environment (the Black Sea): transport versus biogeochemical processes and quantification of the exchanges at the shelf break
Grégoire, Marilaure ULg; Beckers, Jean-Marie ULg; Kostianoy, A. et al

in Commission internationale pour l'exportation Scientifique de la Mer Méditerranée Vol. 36 (2001)

A three-dimensional coupled biogeochemical-hydrodynamical model has been developed to get a better understanding of the biogeochemical functioning of the Black Sea. The in?uence on the ecodynamics of ... [more ▼]

A three-dimensional coupled biogeochemical-hydrodynamical model has been developed to get a better understanding of the biogeochemical functioning of the Black Sea. The in?uence on the ecodynamics of hydrodynamical and biogeochemical processes is quantified. Nitrogen inputs from the rivers, from the sediments and from the deep sea are estimated and compared in terms of potential fertilization. The exchanges between the north-western shelf and the deep sea are quantified. The results illustrate a highly complex spatial variability of the phytoplankton annual cycle and thus, stress the importance of using a 3D model to capture the essential physical-biological interactions that explain the data. [less ▲]

Detailed reference viewed: 3 (1 ULg)
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See detailModelling numerical thinnings in forest management
Rondeux, Jacques ULg

in Rondeux, Jacques (Ed.) Modelling numerical thinnings in forest managment (1985, September)

This paper describes the construction of a simulation model for intensive management of even-aged stands of spruce (Picea abies Karst.) in Belgium. A computer program produces a thinning schedule or a ... [more ▼]

This paper describes the construction of a simulation model for intensive management of even-aged stands of spruce (Picea abies Karst.) in Belgium. A computer program produces a thinning schedule or a guide to reduction in number of trees. Knowing the total production of which a site is capable, the forester may calcultate how many trees growing at a chosen rate are required to use the capacity of this site. The model starts from stand constraints issued from inventories (age, number of stems, top height, mean diameter) and silvicultural constraints (annual diameter increment, rotation age, thinning cycle and thinning type). [less ▲]

Detailed reference viewed: 24 (9 ULg)
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See detailModelling ocean acidification in marginal seas: the North Western European shelf case study
Artioli, Y; Blackford, JC; Butenschön, M et al

Conference (2013)

Detailed reference viewed: 5 (0 ULg)
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See detailModelling of hollow cylinder tests on Boom Clay: softening, anisotropy and strain localization
François, Bertrand; Labiouse, Vincent; You, S. et al

Conference (2012)

Detailed reference viewed: 15 (2 ULg)
See detailMODELLING OF A DOMESTIC GAS-FIRED CONDENSING BOILER
Ballant, Adrien; Makaire, Danielle ULg; Ngendakumana, Philippe ULg

Scientific conference (2008, May)

Within the actual context of energy savings and pollutant emissions reduction, installing condensing boilers becomes indispensable because of their high efficiency compared to conventional boilers. A ... [more ▼]

Within the actual context of energy savings and pollutant emissions reduction, installing condensing boilers becomes indispensable because of their high efficiency compared to conventional boilers. A simulation model predicting boiler performances and condensing rate in the boiler heat exchanger is very valuable. The model developed within this work is a one-dimension model of a domestic gasfired condensing boiler. The aim of the model is to know whether or not the boiler works in good condensing conditions. It gives a better understanding of using and installation requirements of condensing boilers. The structure of the model is similar to a conventional boiler model [1] with a combustion chamber and a dry heat exchanger (HX1), at which a wet heat exchanger (HX2) is added (Figure 1). The calculation consists of evaluating combustion gas temperature and gas composition after the dry heat exchanger. Then, retrievable energy from the flue gas is calculated for a fixed geometry and efficiency of wet heat exchanger and for a fixed return water temperature. The heat transfer coefficient in the wet heat exchanger is calculated according to Liang et al. [2] . The influence of different parameters on condensing performances are analysed: excess air, return water temperature and flue gas mass flow rate for different heat output power. The model has been validated with measurements on a test bench equipped with a 24 kW gas-fired condensing boiler. The test bench is represented on Figure 2. [less ▲]

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See detailMODELLING OF A DOMESTIC GAS-FIRED CONDENSING BOILER
Makaire, Danielle ULg; Ngendakumana, Philippe ULg

Conference (2008, September)

Nowadays, condensing technology is widely used in domestic heating. This paper presents a model that simulates the performance in steady-state regime of a domestic gas-fired condensing boiler. The model ... [more ▼]

Nowadays, condensing technology is widely used in domestic heating. This paper presents a model that simulates the performance in steady-state regime of a domestic gas-fired condensing boiler. The model is similar to a conventional boiler model with a dry heat exchanger at which a wet heat exchanger is added to simulate the heat recovered by condensation. Experimental parameters are used to simulate the different components. The model has been applied to a 24 kW gas-fired condensing boiler test bench available in the laboratory. According to the experimental results (at full load), the model predicts correctly the thermal efficiency of the boiler. Indeed, calculated values are in good agreement with measured values. [less ▲]

Detailed reference viewed: 131 (8 ULg)
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See detailModelling of Accessibility Fields
Donnay, Jean-Paul ULg; Ledent, Philippe

in Proceeding of the First Joint European Conference on Geographical Information (1995)

Detailed reference viewed: 28 (3 ULg)
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See detailModelling of agricultural diffuse pollution and mitigation measures effectiveness inWallonia (Belgium)
Sohier, Catherine ULg; Deraedt, Deborah ULg; Degré, Aurore ULg

in Geophysical Research Abstracts (2012), 14(EGU2012), 9672

Implementation of European directives in the environmental field and, specially, in the water management field, generates a request from policy-makers for news tools able to evaluate impact of management ... [more ▼]

Implementation of European directives in the environmental field and, specially, in the water management field, generates a request from policy-makers for news tools able to evaluate impact of management measures aiming at reducing pressures on ecosystems. In Wallonia (Southern Region of Belgium), the Nitrate Directive (EEC/676/91) was transposed into the “Walloon action plan for nitrogen sustainable management in agriculture” (PGDA1) in 2002. In 2007, a second plan was launched to reinforce some topics (PGDA2). Furthermore, the goal of “good quality” of surface waters and groundwater imposed by the Water Framework Directive poses new challenges in water management. In this context, a “soil and vadose” hydrological model is used in order to evaluate diffuse pollutions and efficiency of mitigation measures. This model, called EPICgrid, has been developed at catchment scale with an original modular concept on the basis of the field scale “water-soil-plant” EPIC model (Williams J.R., Jones C.A., Dyke P.T. (1984). A modelling approach to determining the relationship between erosion and soil productivity. Transactions of the ASAE. 27, 129-144). The model estimates, for each HRU identified into a 1km2 grid, water and nutrients flows into the plant-soil-vadose zone system (Sohier C., Degré A., Dautrebande S. (2009). From root zone modelling to regional forecasting of nitrate concentration in recharge flows – The case of the Walloon Region (Belgium). Journal of Hydrology, Volume 369, Issues 3-4, 15 May 2009, Pages 350-359). The model is used to make prospective simulations in order to evaluate the impact of measures currently performed to reduce the effect of diffuse pollution on water surface quality and groundwater quality, at regional scale. Response of the soil-vadose zone to agricultural practices modification is analyzed for the deadlines of the Water Framework Directive: 2015, 2021 and 2027, taking into account two climatic scenarios. Simulations results showed that actual measures are not sufficient in some areas and that new actions are necessary. The EPICgrid model was also used to evaluate effectiveness of further measures that could be implemented in order to reduce agricultural diffuse pollution. The increasing of catch crops in vulnerable zones has shown a limited impact in theWalloon context. The modifications of agricultural practices such as crop rotations or mineral fertilizing amounts have shown a more significant impact on water quality. Furthermore, the farmers’ practices are evaluated each year by a measuring campaign of the soil nitrogen residue after harvest. These data allow us to improve the representativeness of the EPICgrid model in areas in which agricultural practices largely differs from regional statistics. [less ▲]

Detailed reference viewed: 34 (9 ULg)
Peer Reviewed
See detailModelling of an air condenser working in critical zone for engine cooling by refrigerant loop
Cuevas, Cristian; Winandy, Eric; Lebrun, Jean et al

in 6th Edition of Vehicle Thermal Management Systems (VTMS) Conference (2003, May)

A general and simple model of a condenser for engine cooling by refrigeration loop is presented. The model assumes that the condenser is divided into three distinct zones on the refrigerant side: the ... [more ▼]

A general and simple model of a condenser for engine cooling by refrigeration loop is presented. The model assumes that the condenser is divided into three distinct zones on the refrigerant side: the vapor superheated zone, the two-phase zone and the sub-cooled liquid zone. The model inputs are the dry bulb air supply temperature, the air mass flow rate, the refrigerant supply over-heating, the sub-cooling and the refrigerant mass flow rate. The model is able to give mainly the pressure and temperature in each zone and, of course also, the heat flow and the exhaust enthalpy. The model gives also the geometrical repartition or area percentage of each zone. Adjustable coefficients are used with each correlation to fit the experimental results. An example of identification and validation is presented. The condenser has been tested up to 40 bar with R134a and the model accuracy is within ±2K in condensing temperature prediction. [less ▲]

Detailed reference viewed: 31 (0 ULg)
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See detailMODELLING OF BACTERIAL SULPHATE REDUCTION IN ANAEROBIC PONDS : KINETIC INVESTIGATIONS
Harerimana, Casimir ULg; Vasel, Jean-Luc ULg; Jupsin, Hugues ULg et al

in Australian Water Association (2011)

The aim of the study was first to develop a simple and practical model of anaerobic digestion including sulphate-reduction in anaerobic ponds. The basic microbiology of our model consists of three steps ... [more ▼]

The aim of the study was first to develop a simple and practical model of anaerobic digestion including sulphate-reduction in anaerobic ponds. The basic microbiology of our model consists of three steps, namely, acidogenesis, methanogenesis, and sulphate reduction. This model includes multiple reaction stoichiometry and substrate utilization kinetics. The second aim was to determine some kinetic parameters associated with this model. The values of these parameters for sulfidogenic bacteria are used in the anaerobic pond model to describe the sulphate reduction processes and to evaluate the risk of odour generation. [less ▲]

Detailed reference viewed: 91 (4 ULg)
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See detailModelling of beam-to-column joints for the design of steel building frames.
Maquoi, René ULg; Jaspart, Jean-Pierre ULg

in Proceedings of the Constructional steel design conference (1992)

Detailed reference viewed: 14 (0 ULg)
See detailThe modelling of catalytic trickle-bed reactors
Crine, Michel ULg; Marchot, Pierre ULg

in Chemical Engineering of Gas-Liquid-Solid Reactions (1979)

Detailed reference viewed: 2 (1 ULg)
See detailModelling of Cellular Dynamics
Bullinger, Eric ULg

Conference (2005, September 01)

Detailed reference viewed: 5 (0 ULg)