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See detailOptimisation of SFE method on-line coupled to FT-IR spectroscopy for the real-time monitoring of the extraction of tagitinin C in T-diversifolia
Ziemons, Eric ULg; Mbakop, N. W.; Rozet, Eric ULg et al

in Journal of Supercritical Fluids (2007), 40(3), 368-375

The monitoring in real time of dynamic extractions of tagitinin C from Tithonia diversifolia leaves was carried out with a home made high-pressure fiber optic cell which coupled a supercritical fluid ... [more ▼]

The monitoring in real time of dynamic extractions of tagitinin C from Tithonia diversifolia leaves was carried out with a home made high-pressure fiber optic cell which coupled a supercritical fluid extractor with carbon dioxide as the extraction medium and a FT-IR spectrometer equipped with a mercury cadmium telluride detector (MCT). The shape of extraction curves obtained during the monitoring was used to decide when to stop the supercritical fluid extraction (SFE). No significant density dependence of the molar absorption coefficient or wavenumber of the C=O stretching vibration (v(C=O)) of tagitinin C at 1668 cm(-1) was noticed. The physical characteristics of SCCO2 governing the extraction yield of the active component from leaves were optimized by means of a central composite design (CCD). The studied variables were temperature (40, 60 and 80 degrees C) and pressure (8.0, 14.0 and 20.0 MPa) of the supercritical fluid. The composition profile of T diversifolia extracts obtained by SFE was investigated in the range from 3400 to 2600 cm-1 according to the pressure and temperature conditions of SCCO2. The qualitative approach of the extracts composition was accomplished through the CH stretching vibrations of components. [less ▲]

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See detailOptimisation of ship structures
Rigo, Philippe ULg; Caprace, Jean-David ULg

in Guedes Soares, Carlos; Garbatov, Y.; Fonseca, N. (Eds.) et al Marine Technology and Engineering (2011, May)

Limiting CO2 emissions is a great challenge being faced by society today. Society, through the United Nations Framework Convention on Climate Change (UNFCCC), and actors like the EU, is applying pressure ... [more ▼]

Limiting CO2 emissions is a great challenge being faced by society today. Society, through the United Nations Framework Convention on Climate Change (UNFCCC), and actors like the EU, is applying pressure on all industries, including the shipping industry, to reduce CO2 emissions. This paper presents a way to decrease the GHG emissions by ship scantling optimisation, i.e. decreasing steel weight and keeping the production cost at an acceptable level. The authors first review the links between “Design” and “Optimization” and secondly define the place of “Ship Structure Optimization” within the general framework of a “Ship Optimization”. Then, the LBR-5 ship structure optimisation software is presented. It is based on a convex lin-earization coupled with a dual approach and is based on a rational assessment of the ship structures behaviour. Few applications of structures optimization are then presented. [less ▲]

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See detailOptimisation of slow-release formulations as biological control devices
Heuskin, Stéphanie ULg; Lorge, Stéphanie; Debatty-Mestdagh, Michelle et al

Poster (2010, May 05)

E-β-Farnesene, the alarm pheromone of many aphid species and β-caryophyllene, recently identified as one of the possible component of the aggregation pheromones of the Asian ladybeetles Harmonia axyridis ... [more ▼]

E-β-Farnesene, the alarm pheromone of many aphid species and β-caryophyllene, recently identified as one of the possible component of the aggregation pheromones of the Asian ladybeetles Harmonia axyridis Pallas, are considered as two sesquiterpenes attractive for aphids’ predators and parasitoids, Epysirphus balteatus De Geer and Aphidius ervi Haliday, respectively. In the present research, alginate gel beads formulations were optimised as semiochemical slow-release devices. The formulations were evaluated in terms of volatiles release capacity, protection efficiency of sesquiterpenes against oxidation, and biological activity towards Epysirphus balteatus and Aphidius ervi. Moreover, the sesquiterpenes used in the formulations were obtained from natural matrices. Indeed, they were purified by flash chromatography fractionation of essential oils of Matricaria chamomilla L. and Nepeta cataria L., for obtaining E-β-farnesene and β-caryophyllene, respectively. The purities of the fractions were determined by means of a fast GC analytical method optimised for a good resolution of terpenes in less than five minutes. The experiments can conclude that the alginate gel beads formulations are efficient as biological control devices considering the results obtained with the various biological tests led on predators and parasitoids. Moreover, the sesquiterpenes are more protected when formulated in alginate beads than without formulation. The devices allow also a slow-release of semiochemicals during a long time (at least 40 days) depending on physico-chemical parameters (temperature, relative humidity). A mathematical modelisation of semiochemicals release is presently in study. [less ▲]

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See detailOptimisation of Stiffened Structures
Rigo, Philippe ULg

in Dept. of Naval Architecture and Marine Engineering (2001)

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See detailOptimisation of strength training in trailrunners
Rodriguez de la Cruz, Carlos ULg; Godon, Bernard ULg; Lehance, Cédric ULg et al

in Abstract book du Premier Congrès Olympique Belge de Médecine et des Sciences du Sport (2008)

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See detailThe Optimisation Of The Helix/Helix Interaction Of A Transmembrane Dimer Is Improved By The Impala Restraint Field
Ducarme, P.; Thomas, Annick ULg; Brasseur, Robert ULg

in Biochimica et Biophysica Acta-Biomembranes (2000), 1509(1-2), 148-54

A continuous membrane model (IMPALA) was previously developed to predict how hydrophobic spans of proteins insert in membranes (Mol. Mod. 2 (1996) 27). Using that membrane model, we looked for the ... [more ▼]

A continuous membrane model (IMPALA) was previously developed to predict how hydrophobic spans of proteins insert in membranes (Mol. Mod. 2 (1996) 27). Using that membrane model, we looked for the interactions between several hydrophobic spans. We used the glycophorin A dimer as an archetype of polytopic protein to validate the approach. We find that the native complex do not dislocate when it is submitted to a 10(5) steps optimisation whereas separated spans converge back to a native-like complex in the same conditions. We also observe that IMPALA restraints are not strictly mandatory but do increase the efficiency of the procedure. [less ▲]

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See detailOptimisation of the Nitrogen fertilisation in the context of climate change
Dumont, Benjamin ULg; Basso, Bruno; Bodson, Bernard ULg et al

in Soussana, Jean-Francois (Ed.) Proceedings of the Climate Smart Agriculture 2015 conference (2015, March)

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See detailOptimisation of xanthan gum production by palm date (Phoenix dactylifera L.) juice by-products using response surface methodology
Ben Salah, Riadh; Chaari, Kacem; Besbes, Souhail et al

in Food Chemistry (2010), 121(2), 627-633

The present study was undertaken investigate and optimise the possibility of xanthan gum production by Xanthomonas campestris NRRL B-1459 in batch experiments on date palm juice by-products. Using an ... [more ▼]

The present study was undertaken investigate and optimise the possibility of xanthan gum production by Xanthomonas campestris NRRL B-1459 in batch experiments on date palm juice by-products. Using an experimental Response Surface Methodology complemented with a Central Composite Orthogonal Design, three major independent variables (date juice carbon source, nitrogen source and temperature) were evaluated for their individual and interactive effects on biomass and xanthan gum production. The optimal conditions selected were: 84.68 g/l for carbon source, 2.7 g/l for nitrogen source, and 30.1 degrees C for temperature. The experimental value obtained for xanthan production under these conditions was about 43.35 g/l, which was close to the 42.96 g/l value predicted by the model. Higher yields of biomass production could be obtained at 46.68 g/l for carbon source, 4.58 g/l for nitrogen source and 30 degrees C for temperature. The maximum value obtained for biomass production was 3.35 g/l, which was higher than the 2.98 g/l value predicted by the model. The xanthan formed was subjected to HPLC and TLC analyses and its molecular weight as well as pyruvate content were identified. The findings indicated that this polysaccharide contained glucose, glucoronic acid and mannose. Overall, the date palm juice by-products presented in the current study seem to exhibit promising properties that can open new pathways for the production of efficient and cost-effective xanthan gum. (C) 2010 Elsevier Ltd. All rights reserved. [less ▲]

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See detailOptimisation par éléments finis d'une couronne d'éolienne
Saadi, Ismaïl ULg; Collette, Jean-Paul

in Revue scientifique des ISILF (2013), 27

The purpose of this paper is the study of the most adapted grade of steel that should be used for a ring gear of wind turbine gearboxes. The first step consists in determining a reliable load case in ... [more ▼]

The purpose of this paper is the study of the most adapted grade of steel that should be used for a ring gear of wind turbine gearboxes. The first step consists in determining a reliable load case in order to study the stress to which the part concerned is subjected. After that, a numerical model of the ring gear is designed in a CAD software and then analyzed to rate the stress by the finite element method thanks to ANSYS. In the end, the choice of the grade of steel can be made. [less ▲]

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See detailOPTIMISATION TOPOLOGIQUE : DU MILIEU CONTINU A LA STRUCTURE ELASTIQUE
Duysinx, Pierre ULg

Doctoral thesis (1996)

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See detailOptimisation topologique de micropoutres en vue de maximiser la tension de pull-in
Lemaire, Etienne ULg

Master of advanced studies dissertation (2006)

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See detailL’Optimisation Topologique en Mécanique
Duysinx, Pierre ULg

Article for general public (1999)

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See detailL'optimisation topologique et la fabrication additive, amélioration de la chaine de conception
Louvigny, Yannick ULg; Nzisabira, Jonathan ULg; Meunier, Bertrand et al

in 14ème colloque national AIP PRIMECA : Produits, Procédés, Systèmes intelligents et durables (2015, March)

L'intérêt de combiner l'optimisation topologique avec les méthodes de fabrication additive vient du fait que d'une part, l'optimisation topologique permet de générer des géométries complexes que les ... [more ▼]

L'intérêt de combiner l'optimisation topologique avec les méthodes de fabrication additive vient du fait que d'une part, l'optimisation topologique permet de générer des géométries complexes que les procédés d'usinage conventionnels ne sont pas capables de réaliser et que, d'autre part, la fabrication additive permet de réaliser des formes complexes telles que des cavités emprisonnées dans un volume ou des canaux non rectilignes, impossibles à reproduire en fonderie ou par usinage. De plus et contrairement aux techniques traditionnelles, la réalisation des géométries complexes n'influence pas le coût pour les techniques additives. Pour ces techniques, le coût est lié principalement au volume de la pièce. La complexité de la pièce n'est plus un problème mais un atout. Toutefois cette combinaison n'est pas encore exploitable au niveau industriel. En effet, les résultats fournis par l'optimisation topologique doivent être modifiés, souvent manuellement, pour les rendre utilisables par les méthodes de fabrication additive. Et ces modifications coûtent cher. Il est donc intéressant de limiter ou au mieux d'éliminer les étapes manuelles de la chaîne de conception. Ce papier propose une chaîne de conception optimisée pour une pièce devant être fabriquée par les méthodes additives. En outre, la prise en compte des contraintes inhérentes aux procédés de fabrication par addition de matière reste problématique. Une démarche simplifiée est proposée pour identifier les types de contraintes inhérentes aux procédés de fabrication par addition de matière, les quantifier pour certaines techniques et les intégrer dans le code d'optimisation topologique. La nouvelle chaine de conception minimise les interventions du concepteur qui rendent le processus plus lourd et moins viable industriellement. Dans cette nouvelle chaîne de conception, certaines étapes sont réalisées plus rapidement et génèrent de meilleurs résultats. [less ▲]

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See detailOptimised contrast enhanced nanoCT for volumetric analyses of in vitro manufactured tissue-engineered bone constructs
Sonnaert, Maarten; Kerckhofs, Greet ULg; Papantoniou, Ioannis et al

Conference (2013)

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See detailOptimiser l'expression orale en travaillant sur les stratégies de communication (1re partie)
Dahmen, Manfred; Doppagne, Véronique ULg; Simons, Germain ULg

Conference given outside the academic context (2001)

Detailed reference viewed: 8 (2 ULg)
See detailOptimiser l'expression orale en travaillant sur les stratégies de communication (2nde partie).
Dahmen, Manfred; Doppagne, Véronique ULg; Simons, Germain ULg

Conference given outside the academic context (2002)

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See detailOptimiser l'usage des fourrages auto-produits et viser l'autonomie protéique
Beckers, Yves ULg

Conference given outside the academic context (2011)

Detailed reference viewed: 31 (13 ULg)