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See detailOptimisation et Scale up des Fermentations de Production de Starters Lactiques.
Hamdi, M.; Hamza, S.; Amor, L. et al

Poster (1997, October 27)

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See detailOptimisation methods for initial/tool shape optimisation in metal forming processes
Ponthot, Jean-Philippe ULg; Kleinermann, Jean-Pascal

in International Journal of Vehicle Design (2005), 39(1-2), 14-24

Nowadays, the computer simulations of metal forming processes using the finite element method (FEM), have reached some level of maturity. Inverse problems purpose is to determine one or more of these ... [more ▼]

Nowadays, the computer simulations of metal forming processes using the finite element method (FEM), have reached some level of maturity. Inverse problems purpose is to determine one or more of these forming processes simulations input data, leading to a desired result. A first example that has now become classical is called parameter identification. It consists in evaluating the material parameters for material behaviour laws that would lead to the most accurate model, minimising the difference between experimental and numerical results. Another example, which is much less extensively described in the literature is the initial geometry and tool shape design, which consists in determining the initial shape of the specimen and/or the shape of the forming tools, in order to provide the desired final geometry after forming process. In this paper, we will show how some optimisation methods are able to solve this shape optimisation problems. We will also compare the efficiency of the proposed numerical methods. [less ▲]

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See detailOptimisation objective de paramètres en écoulements turbulents à surface libre sur maillage multibloc
Erpicum, Sébastien ULg

Doctoral thesis (2006)

The chronology of the theoretical and numerical researches outlined in this text is closely linked to our attachment to the physical modelling and to the practical concerns related to important hydraulic ... [more ▼]

The chronology of the theoretical and numerical researches outlined in this text is closely linked to our attachment to the physical modelling and to the practical concerns related to important hydraulic projects. The various applications carried out daily in the HACH , several of the being presented here, enabled to identify the ways to improve the existing numerical models of WOLF , as well as needs in new representation potentialities. The most of the developments described in this text were born from there, with as main objective to increase the capacities of the HACH’s models to help to the management and the design of hydraulic constructions. The hydraulic structures design, and the main part of the practical problems related to free surface flows hydrodynamics, requires both large and small scales studies, with reliable models locally suited to the represented phenomena, and thus variable in a single study depending on the particular point examined. On another hand, the shape and working optimization of hydraulic structures requires robust calibration tools allowing an objective approach. The latter have to be linked to simulation software with modelling capacities and computation times in agreement with the optimization requirements. Both these assessments specify the framework of the researches of this thesis and are at the roots of the definition of the objectives of this work. The first chapters of developments aim to describe the numerical framework of the WOLF package, and more particularly the 1D and 2D models. The rationalization of the computation times for large scale one-dimensional simulations is improved at this stage by implementing in the 1D solver an implicit time integration scheme in parallel to the existing explicit one. Similarly, some improvements have been brought to the solver WOLF2D. They concern the automatic extension of the computation domain regarding the wet and dry cells, the treatment of the slope and roughness source terms with an energetic approach, the water volume conservation as well as the reorganization of the equations resolution scheme in order to be totally free in the choice of the mathematical model to solve. The enrichment of the modelling potentialities of the WOLF software is then pursued by setting, implementing and applying an original turbulence model suited to the specific characteristics of the depth integrated flow modelling. In order to get over the computer and modelling limitations inherent in the use of a single mesh size to model a 2D domain, developments have been carried out to allow the realisation of two-dimensional computations on a structured Cartesian grid composed of several areas with different mesh sizes. In the same way, developments have been carried out to use the whole of the mathematical models available in WOLF2D simultaneously and automatically in a single simulation. The ultimate step of these developments consisted in linking the 1D and the 2D models in a single computation. Following all these steps of developments of hydrodynamic models, a suitable tool for parameters automatic calibration has been set up. Usable with any solver of the WOLF package, it allows the calibration of the whole of the physical parameters present in the hydrodynamic solvers, as well as the resolution of any calibration or optimization problem with these models. The final parallelisation of this Genetic Algorithms based tool opens the door to complex applications, such as the hydraulic design of structures on the basis of two-dimensional simulations of free surface turbulent flows on multiblock grid. At each step, the validation of the developments is rigorously performed through the comparison of the numerical results with those from test cases, theoretical or experimental, original or from the literature. Several practical applications examples illustrate the whole of the developed modelling potentialities and prove their applicability and efficiency facing the most of practical problems encountered by hydraulic engineers. [less ▲]

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See detailOptimisation of a new two-plate screening method for the detection of antibiotic residues in meat
Dang, Pham Kim; Degand, Guy ULg; Douny, Caroline ULg et al

in International Journal of Food Science & Technology (2011), 46

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See detailOptimisation of a semiochemical slow-release alginate formulation attractive towards Aphidius ervi Haliday parasitoids
Heuskin, Stéphanie ULg; Lorge, Stéphanie; Godin, Bruno et al

in Pest Management Science (2011)

BACKGROUND: Optimisation of alginate formulations is described in order to develop semiochemical (E-β-farnesene and E-β-caryophyllene) slow-release devices in biological control approaches by attracting ... [more ▼]

BACKGROUND: Optimisation of alginate formulations is described in order to develop semiochemical (E-β-farnesene and E-β-caryophyllene) slow-release devices in biological control approaches by attracting predators and parasitoids of aphids. Various formulation criteria were optimised with respect to semiochemical encapsulation capacity. Moreover, the optimised formulation was characterised by texturometry and confocal microscopy. The slow-release rates of semiochemicals were calculated in laboratory controlled conditions. The attractiveness of semiochemical formulations towards Aphidius ervi was demonstrated by olfactometry. RESULTS: Two major parameters were highlighted in encapsulation optimisation: the type of alginate (Sigma L) and the type of crosslinker ion (Ca2+). Other formulation parameters were optimised: ionic strength (0.5M), Ca2+ (0.2 M) and alginate (1.5%) concentrations and the maturation time of beads in CaCl2 solution (48 h). After physical characterisation of beads, semiochemical slow-release measurements showed that alginate formulations were efficient sesquiterpene releasers, with 503 μg of E-β-farnesene and 1791 μg of E-β-caryophyllene totally released in 35 days. The efficiency of semiochemical alginate beads as attractants for female parasitoids was demonstrated, with high percentages of attraction for semiochemical odours (88 and 90% for E-β-farnesene and E-β-caryophyllene respectively) and significant statistical results. CONCLUSION: Semiochemical alginate beads can be considered as efficient slow-release systems in biological control. These formulations could be very useful to attract aphid parasitoids on crop fields. [less ▲]

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See detailOptimisation of blocked designs in fMRI studies
Maus, Bärbel ULg; van Breukelen, G. J. P.; Goebel, R. et al

Poster (2009)

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See detailOptimisation of blocked designs in fMRI studies
Maus, Bärbel ULg; van Breukelen, G. J. P.; Goebel, R. et al

Poster (2008)

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See detailOptimisation of culture conditions for biological hydrogen production by Citrobacter freundii CWBI952 in batch, sequenced-batch and semicontinuous operating mode
Hamilton, Christopher ULg; Hiligsmann, Serge ULg; Beckers, Laurent ULg et al

in International Journal of Hydrogen Energy (2010), 35

Investigations were carried out to determine the effect of the pH, the nitrogen source, iron and the dilution rate (h 1) on fermentative hydrogen production from glucose by the newly isolated strain ... [more ▼]

Investigations were carried out to determine the effect of the pH, the nitrogen source, iron and the dilution rate (h 1) on fermentative hydrogen production from glucose by the newly isolated strain Citrobacter freundii CWBI952. The hydrogen production rate (HPR), hydrogen yield, biomass and soluble metabolites were monitored at 30 C in 100 mL serum bottles and in a 2.3 L bioreactor operated in batch, sequenced-batch and semicontinuous mode. The results indicate that hydrogen production activity, formate biosynthesis and glucose intake rates are very sensitive to the culture pH, and that additional formate bioconversion and production of hydrogen with lower biomass yields can be obtained at pH 5.9. In a further series of cultures casein peptone was replaced by (NH4)2SO4, a low cost alternative nitrogen source. The ammonia-based substitute was found to be suitable for H2 production when a concentration of 0.045 g/L FeSO4 was provided. Optimal overall performances (ca. an HPR of 33.2 mL H2/L h and a yield of 0:83 molH2 =molglucose) were obtained in the semicontinuous culture applying the previously optimized parameters for pH, nitrogen, and iron with a dilution rate of 0.012 h 1 and degassing of biogas by N2 at a 28 mL/min flow rate. [less ▲]

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See detailOptimisation of degradable microcarriers for tissue engineering
Lombart, François ULg; Sevrin, Chantal ULg; Flebus, Luca ULg et al

Conference (2013, April 09)

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See detailOptimisation of exercise training in clinical practice for claudicants patients.
Magne, Julien ULg; Boccalon, H; Bouley, M et al

Conference (2003)

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See detailOptimisation Of Expression And Immobilized Metal Ion Affinity Chromatographic Purification Of Recombinant (His)(6)-Tagged Cytochrome P450 Hydroperoxide Lyase In Escherichia Coli
Delcarte, J.; Fauconnier, Marie-Laure ULg; Jacques, P. et al

in Journal of Chromatography B-Analytical Technologies In the Biomedicaland Life Sciences (2003), 786(1-2),

Fatty acid hydroperoxide lyase (HPL) is a cytochrome P450 acting on fatty acid’s hydroperoxides in many plants. The optimisation of the expression of recombinant (His) -tagged HPL in Escherichia coli is ... [more ▼]

Fatty acid hydroperoxide lyase (HPL) is a cytochrome P450 acting on fatty acid’s hydroperoxides in many plants. The optimisation of the expression of recombinant (His) -tagged HPL in Escherichia coli is described: the highest HPL 6 production yield were obtained with TB medium supplemented with 2.5 mM d-aminolevulinic acid and 0.5 mM IPTG. For the first time, the time course expression of a plant P450 in a bench-scale fermentor is detailed and the amount of recombinant HPL production is 16.3 mg/ l. The UV–Visible spectrum of the recombinant (His) -tagged HPL have been recorded after a Ni -based affinity chromatography (IMAC). [less ▲]

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See detailOptimisation of extraction of phenolics and antioxidants from black currant leaves and buds and of stability during storage
Tabart, Jessica ULg; Kevers, Claire ULg; Sipel, Arnaud ULg et al

in Food Chemistry (2007), 105(3), 1268-1275

Health benefits of a diet rich in fruits and vegetables are attributed in part to their contents of phenolics and other antioxidant compounds. In this research, the extraction of phenolics and antioxidant ... [more ▼]

Health benefits of a diet rich in fruits and vegetables are attributed in part to their contents of phenolics and other antioxidant compounds. In this research, the extraction of phenolics and antioxidant compounds from black currant was optimised for different plant organs. The extraction solvent affected yield: aqueous acetone was better than methanol and acetate or glycine buffer. In aqueous buffer, maximum yields of total phenolics and antioxidant activities were obtained at pH 3. Extraction from lyophilised materials yielded extracts with higher phenolic contents and antioxidant activities. Stability of extracts made with acetate or glycine buffer was limited while the use of a mixture of acetone/acetic acid/water for extraction allowed a high phenolic content and antioxidant capacity in dry extract to be maintained for several months. This type of extract could be incorporated in functional food, beverage or dietary supplement. (c) 2007 Elsevier Ltd. All rights reserved. [less ▲]

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See detailOptimisation of hydroelectric power stations operations with WOLF package
Erpicum, Sébastien ULg; Archambeau, Pierre ULg; Dewals, Benjamin ULg et al

in Repp, K.; Westeren, T.; Sandlund, O. T. (Eds.) et al Proceedings of the 5th International Conference on Hydropower - The backbone of sustainable energy supply (2005)

For years, original free-surface flow solvers have been developed and continuously improved by the Laboratory of Applied Hydrodynamics and Hydraulic Constructions (HACH) at the University of Liège. The ... [more ▼]

For years, original free-surface flow solvers have been developed and continuously improved by the Laboratory of Applied Hydrodynamics and Hydraulic Constructions (HACH) at the University of Liège. The resulting fully integrated WOLF computation package allows engineers to accurately study a very wide range of various free surface flows, from hydrological runoff (WOLF HYDRO) and river propagation (WOLF 1D) to extreme erosive flows on realistic mobile topography (WOLF 2D), such as gradual dam breaching processes. All the finite volume models, process oriented, use efficient and original numerical methods to solve free surface flows equations. Each code handles general multiblock meshes, dealing with natural topography, dry and wet cells and mobile bed simultaneously, for any unsteady situation with mixed regimes and moving hydraulic jumps. The interactive and unique user-interface, with high performance pre- and post-processing, allows monitoring 3-D large-scale runs graphically while they proceed, as well as generating 3D videos. In addition, powerful optimisation capabilities based on the Genetic Algorithms technique (WOLF AG) are implemented within WOLF, interconnecting all the package components. An efficient tool is thus available to calibrate physical parameters in any of the models and to manage any problem of optimisation with the different solvers. In this paper, the numerical optimisation process of the system of hydroelectric power stations installed on a 60 km long section of the rivers Amblève and Warche in Belgium is presented in detail. The river network is modelled in quasi-2D using real natural topographic data on almost 1,100 finite volumes. In a first step, the hydrological balance is closed using the solver WOLF HYDRO. Roughness coefficients are calibrated from water level and discharge field measurements. Secondly, the hydroelectric production is maximised by an automatic calibration of the parameters of the hydrograph released in the network at the upstream dam. This approach leads to a substantial gain in hydroelectric production, brings significant financial benefits and deals with all management and security criteria of the river network. [less ▲]

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See detailOptimisation of new biodegradable microcarriers tailored for tissue engineering
Tsoy, A; Sevrin, Chantal ULg; Kottgen, C et al

Poster (2010, October 07)

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See detailOptimisation of new biodegradable microcarriers tailored for tissue engineering
Tsoy, A; Sevrin, Chantal ULg; Köttgen, Cindy et al

Conference (2010, December 10)

Detailed reference viewed: 5 (1 ULg)