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See detailOptimization of dynamic embedded, Water based surface heat (and cold) emitting system for buildings.
Thomas, Sébastien ULg; Franck, Pierre-Yves ULg; Andre, Philippe ULg

Conference (2009, October)

This paper presents the heat flow model and the experimental test bench developed to optimize a new kind of heating floor. In the first part of the text is described the new kind of high reactivity ... [more ▼]

This paper presents the heat flow model and the experimental test bench developed to optimize a new kind of heating floor. In the first part of the text is described the new kind of high reactivity emitting device for building heating and cooling. A second part illustrates the numerical model developed to evaluate the device efficiency. Finally experimental test bench implementation and results are presented. Both computational and experimental results support the use of colder water in comparison to other heating devices. This implies energy savings for building heating. [less ▲]

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See detailOptimization of encoding specificity for the diagnosis of early AD: The RI-48 task
Adam, Stéphane ULg; Van der Linden, Martial ULg; Ivanoiu, A. et al

in Journal of Clinical & Experimental Neuropsychology (2007), 29(5), 477-487

The aim of this study was to evaluate the discriminant validity of the RI-48 test, a shorter French version of the Category Cued Recall portion of the Double Memory Test developed initially by Buschke and ... [more ▼]

The aim of this study was to evaluate the discriminant validity of the RI-48 test, a shorter French version of the Category Cued Recall portion of the Double Memory Test developed initially by Buschke and colleagues (1997), in the diagnosis of mild and very mild Alzheimer disease (AD). The distinctive feature of the RI-48 task is that encoding specificity was increased by adding an immediate cued recall stage at the encoding phase. The results show that the RI-48 task seems to be well adapted to the clinical context and to have good psychometric properties, in particular a lack of a ceiling effect. Moreover, this task appears to be especially well suited for the diagnosis of both mild and very mild AD (sensitivity of 93% and 83.8%). From a more theoretical point of view, this study confirms the importance of optimizing the encoding specificity for the diagnosis of very mild AD, since the more encoding specificity is accentuated, the more discriminating power is increased for the diagnosis of very mild AD. [less ▲]

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See detailOptimization of enzymatic extraction of ferulic acid from wheat bran, using response surface methodology, and characterization of the resulting fractions
Barberousse, Helene; Kamoun, Amel; Chaabouni, Moncef et al

in Journal of the Science of Food and Agriculture (2009), 89(10), 1634-1641

BACKGROUND: The agro-industries generate thousands of tons of by-products, such as bran or pulps, each year. They are, at best, used for cattle feeding. Through biocracking, this biomass may constitute a ... [more ▼]

BACKGROUND: The agro-industries generate thousands of tons of by-products, such as bran or pulps, each year. They are, at best, used for cattle feeding. Through biocracking, this biomass may constitute a renewable source for various molecules of interest for the industry. For instance, ferulic acid, a compound showing antioxidant ability, is found in abundance in cereal bran. Its release depends mainly on the breaking of its ester linkage to other constitutive elements of the cell wall, such as arabinoxylans. Response surface methodology was used to evaluate the effects of ferulic acid esterase (FAE) and xylanase activities, as well as incubation time and temperature, on ferulic acid extraction yield from wheat bran. Under optimized conditions, the composition of the hydrolysate and of residual bran were compared to native bran. RESULTS: Experiments carried out under the predicted optimal conditions (FAE amount, 27 U g(-1); xylanase amount, 304 U g(-1); incubation time, 2 h; and temperature, 65 degrees C) led to an extraction yield of 52.8%, agreeing with the expected value (51.0%). The crude ferulic acid fraction was purified with Amberlite XAD16, leading to a final concentration of 125 mu g mL(-1) of ferulic acid in ethanol. The antioxidant capacity of this purified fraction was evaluated by the DPPH. scavenging method: it exhibited better efficiency (EC50 = 10.6 mu mol L-1 in ferulic acid) than the ferulic acid standard (EC50 = 13.7 mu mol L-1). CONCLUSION: These results confirm the potential of wheat bran valorization in the field of natural antioxidant extraction, possibly viable in an industrial scheme. (C) 2009 Society of Chemical Industry [less ▲]

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See detailOptimization of experimental procedure and statistical data treatment for kinetics of ethylene hydrogenation on a copper-magnesia catalyst
Pirard, Sophie ULg; Heinrichs, Benoît ULg; Heyen, Georges ULg et al

in Chemical Engineering Journal (2008), 138(1-3), 367-378

This study is an example of practical application of kinetic data treatment for simultaneous model discrimination and parameter estimation. The study is applied to the hydrogenation of ethylene on a ... [more ▼]

This study is an example of practical application of kinetic data treatment for simultaneous model discrimination and parameter estimation. The study is applied to the hydrogenation of ethylene on a copper-magnesia catalyst and brings a deepened analysis about the experimental strategy by comparing several alternative strategies using a priori and sequential experimental designs. The best model corresponds to a Langmuir-Hinshelwood mechanism with non-competing adsorption of hydrogen and ethylene and where the rate-determining step is either the addition of molecularly adsorbed hydrogen or the addition of the second atom of hydrogen adsorbed dissociatively. Furthermore, the important question of knowing in practice how many designs and how many measurements per design are actually necessary to determine accurate kinetic and physico-chemical parameters, is addressed. A data correction procedure is also presented that takes catalyst deactivation into account. (C) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailOptimization of external poly base sheet resistance in 0.13 µm quasi self-aligned SiGe:C HBTs
You, Suzhen; Van Huylenbroeck, Stefaan; Nguyen, Ngoc Duy ULg et al

in Thin Solid Films (2009), 518(6), 68

This paper investigates the optimization of the external polysilicon base sheet resistance of quasi self-aligned (QSA) SiGe:C HBTs from a 0.13 μm BiCMOS process. Taking advantage of optimized implant ... [more ▼]

This paper investigates the optimization of the external polysilicon base sheet resistance of quasi self-aligned (QSA) SiGe:C HBTs from a 0.13 μm BiCMOS process. Taking advantage of optimized implant conditions to improve the doping of the external base poly, and using an optimized non-selective epitaxy process with improved growth rate ratio of 1.7 between the polycrystalline silicon and monocrystalline silicon of the base, the maximum oscillation frequency fmax reaches 300 GHz. [less ▲]

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See detailOptimization of flexible components in reciprocating engines with cyclic dynamic loading
Tromme, Emmanuel ULg; Bruls, Olivier ULg; Duysinx, Pierre ULg

in Samin, Jean-Claude; Fisette, Paul (Eds.) Proceedings of Multibody Dynamics 2011, Eccomas Thematic Conference: Brussels (Belgium), 4-7 juillet 2011 (2011, July 05)

This work considers the optimization of flexible components of mechanical systems modeled as multibody systems. This approach permits to better capture the effects of dynamic loading under service ... [more ▼]

This work considers the optimization of flexible components of mechanical systems modeled as multibody systems. This approach permits to better capture the effects of dynamic loading under service conditions. This process is challenging because most state-of-the-art studies in structural optimization have been conducted under static or quasi-static conditions. The formulation of the optimization problem for dynamic systems is fundamental; it is not a simple extension of static optimization. Naive implementation leads to fragile and unstable results. The present paper addresses the optimization of a connecting rod of a reciprocating engine with cyclic dynamic loading. Gradient-based methods are adopted for their convergence speed. Different formulations are investigated and compared. A first numerical application considers the optimization of the connecting rod regarding its mass and its elongation. After, another numerical application is carried on considering the stresses in the connecting rod. A conclusion on the influence of the optimization problem formulation is realized. [less ▲]

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See detailOptimization of formic/acetic acid delignification of Miscanthus ×giganteus for enzymatic hydrolysis using response surface methodology
Vanderghem, Caroline ULg; Brostaux, Yves ULg; Jacquet, Nicolas ULg et al

in Industrial Crops & Products (2012), 35

A Box–Behnken experimental design and response surface methodology were employed to optimize the pretreatment parameters of a formic/acetic acid delignification treatment of Miscanthus ×giganteus for ... [more ▼]

A Box–Behnken experimental design and response surface methodology were employed to optimize the pretreatment parameters of a formic/acetic acid delignification treatment of Miscanthus ×giganteus for enzymatic hydrolysis. The effects of three independent variables, namely cooking time (1, 2 and 3 h), formic acid/acetic acid/water ratio (20/60/20, 30/50/20 and 40/40/20) and temperature (80, 90 and 107 ◦C) on pulp yield, residual Klason lignin content, concentration of degradation products (furfural and hydroxymethylfurfural) in the black liquor, and enzymatic digestibility of the pulps were investigated. The major parameter influencing was the temperature for pulp yield, delignification degree, furfural production and enzymatic digestibility. According to the response surface analysis the optimum conditions predicted for a maximum enzymatic digestibility of the glucan (75.3%) would be obtained using a cooking time of 3 h, at 107 ◦C and with a formic acid/acetic acid/water ratio of 40/40/20%. Glucan digestibility was highly dependent on the delignification degree. [less ▲]

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See detailOptimization of Hull Structures for a 60 meters Mega Yacht
Motta, Dario; Caprace, Jean-David ULg; Rigo, Philippe ULg et al

in Proceeding of the 11th International Conference on Fast Sea Transportation (2011, September)

As well known already in earliest phases of a ship project many aspects and choices depend on the structural design which has been defined only at a preliminary level. This trend appears to be similar for ... [more ▼]

As well known already in earliest phases of a ship project many aspects and choices depend on the structural design which has been defined only at a preliminary level. This trend appears to be similar for merchant ships, passenger ships and motor yachts. Only in the final part of the project some shipyards begin to apply optimization processes, more or less sophisticated, in order to refine the structural design in view of reducing the weight and/or the construction cost. The weight in particular has a very important impact on pleasure vessels, both motor and sailing. Structural modifications suggested by such optimization procedures imply a number of second order changes in related items such as plant, outfitting and others. As a consequence the structural optimization could be particularly useful if it can be applied during the first stages of the project, this way avoiding very expensive time losses and changes caused by any structural modifications. In this paper the structural optimization of a 60 meters megayacht is presented, performed by LBR-5 code developed by the University of Liege. This code is an optimization tool specifically designed for structures composed by stiffened plates and stiffened cylindrical shells. The optimal solution is reached through an optimization algorithm based on convex linearization and a dual approach. The LBR-5 software has been successfully utilized to optimize hull structures of a 60 meters megayacht. Differently from large ships, the mega yacht has not a “cylindrical body” in the central part of the hull. So, a new module of the software has been used in order to analyze several sections of the ship and to perform an overall optimization. For this application the optimization analysis has been carried out by different approaches: assuming the weight as the objective function a gain of about 8% has been achieved, while a least cost optimization allowed a reduction of 15%. [less ▲]

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See detailOPTIMIZATION OF HUMAN ES CELLS (hESCs) CRYOPRESERVATION
Connan, Delphine ULg; Ectors, Fabien ULg; Grobet, Luc ULg et al

Poster (2012, October 22)

Detailed reference viewed: 34 (14 ULg)
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See detailOptimization Of Issr Marker For African Edible-Seeded Cucurbitaceae Species' Genetic Diversity Analysis
Dje, Yao; Tahi, G. C.; Zoro Bi, Arsène I. et al

in African Journal of Biotechnology (2006), 5(2), 83-87

Detailed reference viewed: 22 (2 ULg)
See detailOptimization of Large Flexural Finite Element Systems
Fleury, Claude ULg

in HAUG, Edward J.; CEA, Jean (Eds.) Optimization of distributed parameter structures. Proceedings of the NATO advanced study institute held in Iowa City, Iowa, on May 20-June 4, 1980 (1981)

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See detailOptimization of ligand-binding assay in a QbD environment. Use of Bayesian non-linear regression to set up probability profile as quality response
Lebrun, Pierre ULg; Boulanger, Bruno ULg; Hubert, Philippe ULg

Conference (2010, September 28)

For ligan-binding assay, different parameters are controlled in routine. In a development phase, we will show how design of experiment can be used to select these parameters to obtain reliable results in ... [more ▼]

For ligan-binding assay, different parameters are controlled in routine. In a development phase, we will show how design of experiment can be used to select these parameters to obtain reliable results in the future use of the ELISA test. Uncertainties of measurements and models should be taken into account in a predictive manner. Bayesian modelling and MCMC simulations are well suited for this purpose and are flexible enough to include random effects on the parameters on non-linear model. We will focus on 4PL regression as it is encountered in most applications. We will also show that deriving a quality response such as a precision profile is clear and direct in the Bayesian setting. The approach is fully compliant with QbD guidelines and Design Space definition. [less ▲]

Detailed reference viewed: 91 (13 ULg)
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See detailOPTIMIZATION OF LIPASE-CATALYZED SYNTHESIS OF CITRONELLYL ACETATE IN SOLVENT-FREE MEDIUM
Fonteyn, Fabienne ULg; Blecker, Christophe ULg; Lognay, Georges ULg et al

in Biotechnology Letters (1994), 16(7), 693-696

Citronellol esterification catalyzed by Candida antarctica lipase is performed with high yields (74%) in a solvent-free medium. The use of dessicants gives a 10% yield enhancement and substrate excess ... [more ▼]

Citronellol esterification catalyzed by Candida antarctica lipase is performed with high yields (74%) in a solvent-free medium. The use of dessicants gives a 10% yield enhancement and substrate excess consumption by adding calculated amounts of acetic acid lead to a 80% pure citronellyl acetate. Quantities up to 100 ml are treated with success. [less ▲]

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See detailOptimization of Matrix Conditions for the Control of MALDI In-Source Decay of Permethylated Glycans.
Smargiasso, Nicolas ULg; De Pauw, Edwin ULg

in Analytical Chemistry (2010), sous presee

Due to its fastness and its easiness to use, MALDI-MS is currently an analytical tool widely used in glycomic applications. However, the MALDI ionization process could result in the so-called "in-source ... [more ▼]

Due to its fastness and its easiness to use, MALDI-MS is currently an analytical tool widely used in glycomic applications. However, the MALDI ionization process could result in the so-called "in-source decay", or ISD, of analytes, leading to complex spectra. On the other hand, ISD opens the possibility to perform pseudo-MS(3) experiments. This phenomenon must therefore be controlled in order to be used on demand as a supplementary tool for the analysis of permethylated glycans by MALDI mass spectrometry. For this purpose, several matrices were tested and MALDI imaging was used to determine optimal conditions promoting or, inversely, avoiding ISD of permethylated glycans. 2,5-DHB was shown to be a versatile matrix allowing one to induce or prevent ISD according to the location of laser shots. Inversely, it was shown that 9-aminoacridine forms homogeneous spots and avoids completely ISD. This matrix would therefore be suitable for automatic analysis. [less ▲]

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See detailOptimization of mechatronic systems: application to a modern car equipped with a semi-active suspension
Duysinx, Pierre ULg; Bruls, Olivier ULg; collard, Jean-François et al

in Herskowitz, José (Ed.) Proceedings of the 6th World Congress of Structural and Multidisciplinary Optimization (WCSMO6) (2005, May)

The research aims at developing a global mechatronic approach to model, simulate and optimize complex industrial applications. The approach is illustrated with the simulation and the optimization of a ... [more ▼]

The research aims at developing a global mechatronic approach to model, simulate and optimize complex industrial applications. The approach is illustrated with the simulation and the optimization of a modern car (an Audi A6) equipped with a controlled semi-active suspension. An optimization procedure is used to find the best sub-system parameters in order to improve the comfort of the passengers while preserving the car ride and handling performances. Two different modeling and optimization approaches are used and compared. The first one is realized in the MATLAB-SIMULINK environment and is based on a symbolic multibody model of the chassis while the hydraulic actuators, and the controller are integrated using S-functions. Optimization is also carried out in MATLAB using algorithms available in MATLAB libraries, especially a genetic algorithm (GA). On the other hand, the second approach relies on a multibody model based on the Finite Element method whereas the optimization can be realized with an industrial open optimization tool. [less ▲]

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See detailOptimization of micro-HPLC peak focusing for the detection and quantification of low hepcidin concentrations.
Mansion, François ULg; Chiap, Patrice ULg; Houbart, Virginie ULg et al

in Journal of Separation Science (2011), 34(15), 1820-1827

Micro-high-performance liquid chromatography is a miniaturized, economic and ecological chromatographic system allowing the use of reduced size chromatographic columns. Coupled with electrospray ... [more ▼]

Micro-high-performance liquid chromatography is a miniaturized, economic and ecological chromatographic system allowing the use of reduced size chromatographic columns. Coupled with electrospray ionization tandem mass spectrometry, this technique can be used to detect and quantify low concentrations of peptides. In this study, hepcidin was used as the model compound and analysed using octadecylsilica stationary phase by means of a gradient elution mode at a flow rate of 4 muL/min. Several parameters were studied to optimize peak focusing. Using the methodology of experimental design, the mobile-phase gradient conditions and the sample composition were optimized in order to maximize the sensitivity and minimize retention time. Stability of the target peptide in solution was also demonstrated. [less ▲]

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See detailThe optimization of microsatellite genotyping and genetic sexing of non-invasively collected polar bear tissue: Implications for monitoring and census.
Harris, Christopher; Van Coeverden De Groot, Peter; Kamookak, L et al

Conference (2012, April)

The monitoring of Polar Bears in Canada has been completed largely through management unit (MU) wide capture-mark-recapture (CMR) surveys. While this data is very useful at the time of collection, these ... [more ▼]

The monitoring of Polar Bears in Canada has been completed largely through management unit (MU) wide capture-mark-recapture (CMR) surveys. While this data is very useful at the time of collection, these surveys are expensive and take time to plan and execute; cannot be feasibly executed across the polar bear range at intervals that reflect the expected rapid environmental changes in the Arctic; and are disdained by the Inuit as being invasive. As part of recent efforts to explore less expensive and non-invasive methods to monitor polar bears (see Wong et al & Van Coevderden de Groot et al this conference) we are evaluating genetic information obtained from non-invasively collected polar bear tissue. In this work we report on the genetic data obtained from non-invasively collected harisnags recovered from sampling stations erected between May-June 2006-2009 in M’Clintock Channel, Nunavut. Across the 4 years 344 hair snags were collected; following Paetkau (2004) we optimized 6 microsatellite loci to reliably amplify polar bear DNA from this tissue and we modified the procedure of Pages et al (2009) to reliably genetically sex these tissues. Our estimates for two common errors with this type of tissue across all loci – allelic dropout (0.026) and false allele (0.03) - were both less than p =.05. This suggests these errors are not going to significantly affect the accuracy of the consensus genotypes collected from these data. Using consensus genotypes from relevant hairsnags, we posit a minimum of 59 (max 82) unique bears entered our sampling stations. Of these, 24% were female, 64% were male, and 12% could not be sexed. We resampled 2 bears in 2006, 1 in 2007, 0 bears in 2008 and 14 bears in 2009 – the 2009 value reflects significantly increased sampling effort in 2009. Five bears were re-sampled between the non-invasive surveys in 2006-2009. When comparing our data to a subset of cubs and subadults captured during the Taylor et al. (2006) CMR survey of M’Clintock Channel (MU), we found 6 genotype matches. Our sampling stations may have a male bias as the sex ratio from the 1998-2000 CMR study was 42.1% ♂ (Taylor et al 2006) vs. 64% ♂ (this study). We cannot accurately determine the age bias (but see Wong et al this conference). Genetic data from Polar bear faecal samples may provide an unbiased sex and age sample of polar bears in any MU. Any data from these samples will help refine hairsnag derived MKNA estimate of polar bears from any MU. Here we report on our efforts to genotype and genetically sex 95 faecals we have collected from M’Clintock Channel from 2006-2009. Finally, we discuss the implications of these findings, results from other noninvasive work (Wong et al & Van Coevderden de Groot et al this conference) and ongoing/proposed work in the context of i) a non-invasive Inuit-based polar bear activity and health survey, and ii) a more rigorous census method which may allow more precise adjustments of harvest levels than currently possible using infrequently collected CMR data only. [less ▲]

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See detailOptimization of monopile offshore wind structures
Thiry, Arnaud; Rigo, Philippe ULg; Buldgen, Loïc ULg et al

in Marstruct (2011)

ABSTRACT: As industrialization is essential for large-scale offshore wind deployment, a computerized methodology to optimize the scantling of monopile steel structures has been developed using a genetic ... [more ▼]

ABSTRACT: As industrialization is essential for large-scale offshore wind deployment, a computerized methodology to optimize the scantling of monopile steel structures has been developed using a genetic alg rithm. The objective functions of this tool are minimization of the structure weight and production costs. The constraints implemented are mainly related to structural stability under extreme loads, resonance check of the wind turbine support and fatigue strength at welded connections between shells and stiffeners. This optimiz tion should be invoked at the preliminary stage of the offshore project in order to assess the impacts of the structure design on the fabrication and installation costs. [less ▲]

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See detailOptimization of multibody systems and their structural components
Bruls, Olivier ULg; Lemaire, Etienne ULg; Duysinx, Pierre ULg et al

in Blajer, W.; Arczewski, K.; Fraczek, J. (Eds.) et al Multibody Dynamics: Computational Methods and Applications (2011)

This work addresses the optimization of flexible multibody systems based on the dynamic response of the full system with large amplitude motions and elastic deflections. The simulation model involves a ... [more ▼]

This work addresses the optimization of flexible multibody systems based on the dynamic response of the full system with large amplitude motions and elastic deflections. The simulation model involves a nonlinear finite element formulation, a time integration scheme and a sensitivity analysis and it can be efficiently exploited in an optimization loop. In particular, the paper focuses on the topology optimization of structural components embedded in multibody systems. Generally, topology optimization techniques consider that the structural component is isolated from the rest of the mechanism and use simplified quasi-static load cases to mimic the complex loadings in service. In contrast, we show that an optimization directly based on the dynamic response of the flexible multibody system leads to a more integrated approach. The method is applied to truss structural components. Each truss is represented by a separate structural universe of beams with a topology design variable attached to each one. A SIMP model (or a variant of the power law) is used to penalize intermediate densities. The optimization formulation is stated as the minimization of the mean compliance over a time period or as the minimization of the mean tip deflection during a given trajectory, subject to a volume constraint. In order to illustrate the benefits of the integrated design approach, the case of a two degrees-of-freedom robot arm is developed. [less ▲]

Detailed reference viewed: 85 (15 ULg)