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See detailApplication of random eigenvalue analysis to assess bridge flutter probability
Canor, Thomas; Caracoglia, Luca; Denoël, Vincent ULg

in Journal of Wind Engineering and Industrial Aerodynamics (2015), 140(0), 79--86

Abstract This study examines the well-known issue of evaluating the flutter probability for a long-span bridge, necessary for assessing structural integrity and reliability. The motivation stems from the ... [more ▼]

Abstract This study examines the well-known issue of evaluating the flutter probability for a long-span bridge, necessary for assessing structural integrity and reliability. The motivation stems from the need for critically reviewing and investigating a number of existing numerical approaches (e.g., random perturbation analysis, collocation methods, Galerkin approach) for the modeling and the solution of stochastic dynamic problems, by adapting them to the specific problem. The study proposes a generalized formulation for stochastic bridge flutter in terms of random eigenvalue analysis. A 1200 m suspension bridge model is used in the numerical simulations to compare the various methods and to provide indications on advantages and limitations of each method. Moreover, the link between the proposed formulation and existing studies on the propagation of uncertainty in aeroelastic systems, for example associated with measurement errors in wind tunnel, is examined. [less ▲]

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See detailApplication of RAP-PCR and cDNA-AFLP to isolate genes of Candida oleophila (strain O) induced by the presence of galacturonic acid.
Massart, Sébastien ULg; Sens-Espel, Roser; Lepoivre, Philippe ULg et al

in Bulletin OILB/SROP = IOBC/WPRS Bulletin (2002), 25(10), 399-402

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See detailApplication of real-time voltage security assessment to the Hellenic Interconnected System
Van Cutsem, Thierry ULg; Kabouris, John; Christoforidis, George et al

in IEE Proceedings-Generation Transmission and Distribution (2005), 152(1), 123-131

The online voltage security assessment methods implemented at the national control centre of the Hellenic Interconnected System, within the framework of the OMASES project funded by the European Union are ... [more ▼]

The online voltage security assessment methods implemented at the national control centre of the Hellenic Interconnected System, within the framework of the OMASES project funded by the European Union are described. The heart of all computations is a fast time-domain method. Security is analysed with respect to power transfers in critical corridors or power consumption in load areas. Results take on the form of either precontingency secure operation limits, or postcontingency loadability limits, together with various diagnosis tips. Contingency filtering is performed to meet the real-time requirement. Typical results obtained during the test phase of the project are reported. [less ▲]

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See detailApplication of recombinant sucrose synthase large scale synthesis of ADP-glucose
Zervosen, Astrid ULg; Romer, Ulrike; Elling, Lothar

in Journal of Molecular Catalysis B : Enzymatic (1998), 5(1-4), 25-28

Abstract The synthesis of ADP-glucose with recombinant sucrose synthase from potato was combined with the synthesis of ADP from AMP and ATP catalysed by myokinase from rabbit muscle. By using the ... [more ▼]

Abstract The synthesis of ADP-glucose with recombinant sucrose synthase from potato was combined with the synthesis of ADP from AMP and ATP catalysed by myokinase from rabbit muscle. By using the repetitive-batch-technique we were able to reach enzyme productivities (mg ADP-glucose/U enzyme) of 28 mg/U sucrose synthase and 140 mg/U myokinase yielding 2.8 g ADP-glucose (55% yield). After product isolation, 2.2 g ADP-glucose was obtained corresponding to 44% overall yield. [less ▲]

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See detailApplication of reinforcement learning to electrical power system closed-loop emergency control
Druet, Christophe; Ernst, Damien ULg; Wehenkel, Louis ULg

in Principles of Data Mining and Knowledge Discovery, 4th European Conference, PKDD 2000 (2000)

This paper investigates the use of reinforcement learning in electric power system emergency control. The approach consists of using numerical simulations together with on-policy Monte Carlo control to ... [more ▼]

This paper investigates the use of reinforcement learning in electric power system emergency control. The approach consists of using numerical simulations together with on-policy Monte Carlo control to determine a discrete switching control law to trip generators so as to avoid loss of synchronism. The proposed approach is tested on a model of a real large scale power system and results are compared with a quasi-optimal control law designed by a brute force approach for this system. [less ▲]

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See detailThe application of reporter gene assays for the detection of endocrine disruptors in sport supplements
Plotan, Monica; Elliott, Chris; Scippo, Marie-Louise ULg et al

in Analytica Chimica Acta (2011), 700

The increasing availability and use of sports supplements is of concern as highlighted by a number of studies reporting endocrine disruptor contamination in such products. The health food supplement ... [more ▼]

The increasing availability and use of sports supplements is of concern as highlighted by a number of studies reporting endocrine disruptor contamination in such products. The health food supplement market, including sport supplements, is growing across the Developed World. Therefore, the need to ensure the quality and safety of sport supplements for the consumer is essential. <br />The development and validation of two reporter gene assays coupled with solid phase sample preparation enabling the detection of estrogenic and androgenic constituents in sport supplements is reported. Both assays were shown to be of high sensitivity with the estrogen and androgen reporter gene assays having an EC50 of 0.01 ng mL-1 and 0.16 ng mL-1 respectively. <br />The developed assays were applied in a survey of 63 sport supplements samples obtained across the Island of Ireland with an additional seven reference samples previously investigated using LC-MS/MS. Androgen and estrogen bio-activity was found in 71 % of the investigated samples. Bio-activity profiling was further broken down into agonists, partial agonists and antagonists. Supplements (13) with the strongest estrogenic bio-activity were chosen for further investigation. LC-MS/MS analysis of these samples determined the presence of phytoestrogens in seven of them. Supplements (38) with androgen bio-activity were also selected for further investigation. Androgen agonist bio-activity was detected in 12 supplements, antagonistic bio-activity was detected in 16 and partial antagonistic bio-activity was detected in 10. A further group of supplements (7) did not present androgenic bio-activity when tested alone but enhanced the androgenic agonist bio-activity of dihydrotestosterone when combined. <br />The developed assays offer advantages in detection of known, unknown and low-level mixtures of endocrine disruptors over existing analytical screening techniques. For the detection and identification of constituent hormonally active compounds the combination of biological and physio-chemical techniques is optimal. [less ▲]

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See detailApplication of shearography to crack detection in concrete structures subjected to traffic loading
Muzet, Valérie; Blain, Pascal ULg; Przybyla, David

in Armando Albertazzi, Armando Jr.; Kaufmann, Guillermo H. (Eds.) Speckle 2010: Optical Metrology (2010, September 13)

Early detection of defects in concrete structures, such as bridges or dams, is essential to optimize the maintenance of civil engineering facilities. Optical methods constitute non-destructive means of ... [more ▼]

Early detection of defects in concrete structures, such as bridges or dams, is essential to optimize the maintenance of civil engineering facilities. Optical methods constitute non-destructive means of control and measurement but they are generally confined in laboratories where both the setup and environnement are controlled. The method of shearography is especially well adapted to detect damages due to both its capacity to distinctly visualize strain concentration zones and its robustness. The experimental set-up is relatively compact, which enables to examine an extensive surface area by simply moving the shearographic head. In this paper, the application of this methodology for the detection of cracks is presented on concrete samples and circulated outside concrete structures. Due to its sensitivity to strain concentration, shearography is able to detect structural cracks, even when they were not through-cracks. Operational implementation is made on two circulated structures with experts in manual cracks detection. No stimulation device is used. In the first structure, cracks are detected on the bridge deck and on the bridge abutment. In the second structure, cracks on the intrados of the bridge deck are detected and also beginning of cracks which have not been detected by the visual inspection. Different areas are scanned and the results are in agreement with the visual inspection. This technique enables detecting cracks on structures subjected to traffic load. The natural loading of an engineering structure, i.e. the rolling traffic it bears, proves well suited for cracks detection by means of shearography, provided traffic patterns are regular enough. [less ▲]

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See detailApplication of space-time adaptive processing (STAP) to conformal arrays
Ries, Philippe; Lapierre, Fabian D.; Verly, Jacques ULg

Conference (2004)

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See detailApplication of space-time adaptive processing (STAP) to conformal arrays
Ries, Philippe; Lapierre, Fabian D.; Verly, Jacques ULg

Conference (2005)

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See detailThe application of spatial autocorrelation methods to the study of Calluna vulgaris population genetics
Mahy, Grégory ULg; Néve, Gabriel

in Belgian Journal of Botany (1997), 129

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See detailApplication of stable isotopes in trophic ecology: importance of TEF and seasonal baseline for robust interpretations.
Remy, François ULg; Darchambeau, François ULg; Dauby, Patrick ULg et al

Conference (2015, April 02)

Nitrogen, carbon and sulfur stable isotopes are very powerful tools for trophic ecologists to delineate food webs of various ecosystems. More recently… the use of mixing models has exponentially increased ... [more ▼]

Nitrogen, carbon and sulfur stable isotopes are very powerful tools for trophic ecologists to delineate food webs of various ecosystems. More recently… the use of mixing models has exponentially increased to give a more specific vision of organism’s diets and trophic relationships. Two case studies will be presented to give a summary of what’s been done in Liège Oceanology Lab to improve our interpretation of stable isotopes results. First is an experimental calculation of the Trophic Enrichment Factors (TEFs) for one dominant detritivorous species of Mediterranean amphipod inhabiting seagrass detritus: Gammarus aequicauda (Martynov, 1931). This experimental study was planned after a strange result of the SAIR mixing model, giving results opposed to all observations and knowledge we had about this species. Thus, the impact of 3 very different food sources (amphipod powder, algae power, seagrass powder) on the turnover rate of C and N isotopic compositions was tested, and afterwards TEFs for C and N for each source were calculated. Animal food source showed to be the most effectively assimilated with a fast turnover rate while seagrass and algae showed very slow assimilation. TEFs calculations showed to be interesting because TEFs seem not to depend on the natural feeding type of the invertebrate but more on the type of food source. Animal source showed carnivorous TEFs values while seagrass and algae source showed typical detritivorous values. SIAR results with these new custom values gave more coherent values highlighting the major importance of TEFs values for mixing models data interpretation. Second is a simple question: are the seasonal isotopic composition variations observed for many seagrass detritus macrofauna species due to actual diet changes, or only to isotopic baseline shift of the food sources? Macrofauna and all potential food sources were sampled near STARESO Oceanographic Station (Corsica, 8°45’E; 42°35’N) in 2011-2012 at each season at two different sites. SIBER software runs with C and N isotopic data showed spatio-temporal isotopic variations at community, interspecific and intraspecific level. SIBER did not gave us information about the origin of these changes, but coupled with SIAR and our custom TEFs, species actually showing drastic changes of diet were identified, while others seem to reflect more a source baseline isotopic composition shift. Working at specific level is compulsory for fine conclusions. These two case studies highlight the importance of mixing model use and of accurate TEF values to run these models properly to draw robust and reliable conclusions using stable isotopic data. [less ▲]

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See detailApplication of Steam Explosion as Pretreatment on Lignocellulosic Material: A Review
Jacquet, Nicolas ULg; Maniet, Guillaume ULg; Vanderghem, Caroline ULg et al

in Industrial & Engineering Chemistry Research (2015), 54(10), 2593-2598

Steam explosion is a thermo-mechanicochemical pretreatment which allows the breakdown of lignocellulosic structural components by the action of heating, formation of organic acids during the process, and ... [more ▼]

Steam explosion is a thermo-mechanicochemical pretreatment which allows the breakdown of lignocellulosic structural components by the action of heating, formation of organic acids during the process, and shearing forces resulting in the expansion of the moisture. Two distinct stages compose the steam-explosion process: vapocracking and explosive decompression which include modification of the material components: hydrolysis of hemicellulosic components (mono- and oligosaccharides released), modification of the chemical structure of lignin, and modification of the cellulose crystallinity index, etc. These effects allow the opening of lignocellulosic structures and influence the enzymatic hydrolysis yield of the material. [less ▲]

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See detailApplication of sucrose synthase from rice grains for the synthesis of carbohydrates.
Elling, Lothar; Grothus, Marita; Zervosen, Astrid ULg et al

in Annals of the New York Academy of Sciences (1995), 750

The enzymatic synthesis of oligosaccharides offers an efficient way to obtain regiospecific and stereo-selective natural and nonnatural target molecules. However, the very expensive activated sugars are ... [more ▼]

The enzymatic synthesis of oligosaccharides offers an efficient way to obtain regiospecific and stereo-selective natural and nonnatural target molecules. However, the very expensive activated sugars are required as substrates for glycosyltransferases. Activated sugars are usually synthesized by pyrophosphorylases from nucleoside triphosphates and sugar-l-phosphates.'.* For cyclic in situ regeneration, at least three enzymes are needed, which makes the synthesis of, for example, N-acetyllactosamine very complex by established procedure. We report here on the enzymatic synthesis of saccharides and activated sugars by the plant glycosyltransferase sucrose synthase (EC 2.4.1.13)! The glycosyltransferase has the unique feature of catalyzing in vitro the synthesis and cleavage of sucrose (SCHEME1 ). The main advantage of sucrose synthase over pyrophosphorylases is the utilization of nucleoside diphosphates (NDP) instead of nucleoside triphosphates to generate activated sugars. [less ▲]

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See detailApplication of sucrose synthase in the synthesis of nucleotide sugars and saccharides
Zervosen, Astrid ULg; Elling, Lothar

in Bucke, Christopher (Ed.) Carbohydrate Biotechnology Protocols (1999)

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See detailApplication of Supercritical Carbon Dioxide for the Preparation of a Piroxicam-Beta-Cyclodextrin Inclusion Compound
Van Hees, Thierry ULg; Piel, Géraldine ULg; Evrard, Brigitte ULg et al

in Pharmaceutical Research (1999), 16(12), 1864-70

PURPOSE: Piroxicam is a poorly soluble NSAID, whose solubility is enhanced when included into beta-cyclodextrin. The preparation of a piroxicam-beta-cyclodextrin inclusion compound using supercritical CO2 ... [more ▼]

PURPOSE: Piroxicam is a poorly soluble NSAID, whose solubility is enhanced when included into beta-cyclodextrin. The preparation of a piroxicam-beta-cyclodextrin inclusion compound using supercritical CO2 was investigated. METHODS: The solubility and the stability of piroxicam in supercritical CO2 were determined. Then, the influence of the temperature, the pressure and the time of exposure on the inclusion rate was studied. RESULTS: The solubility of piroxicam varied over a wide range depending on the temperature and pressure (from 0.006 to 1.500 mg/g of CO2). The temperature and the time of exposure had a great influence on the inclusion yield, while pressure did not and a complete inclusion was achieved by keeping a physical mixture of piroxicam and beta-cyclodextrin (1:2.5 mol/mol) for 6 hours at 150 degrees C and 15 MPa of CO2. This complex was characterized by Differential Scanning Calorimetry, differential solubility and Fourier Transform Infrared Spectrometry. CONCLUSIONS: Supercritical carbon dioxide may prove to be a novel useful complexation method of drugs into beta-cyclodextrin. [less ▲]

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See detailApplication of Supercritical carbon dioxide for the preparation of drug-cyclodextrin inclusion compounds
Van Hees, Thierry ULg; Barillaro, Valery; Piel, Géraldine ULg et al

in Journal of Inclusion Phenomena and Macrocyclic Chemistry (2002), 44(1-4), 271-274

Inclusion complexes of drugs into cyclodextrins (CDs) can be obtained at the solid state by means of supercritical dioxide (SCCO2). A successful inclusion with a yield >98.5% has been achieved with ... [more ▼]

Inclusion complexes of drugs into cyclodextrins (CDs) can be obtained at the solid state by means of supercritical dioxide (SCCO2). A successful inclusion with a yield >98.5% has been achieved with piroxicam and beta-CD. The temperature and the time of exposure to SCCO2 have a significant effect on the inclusion yield while the pressure has a negative effect. However, there is a strong interaction between temperature and pressure and this interaction has a positive influence. The molar ratio piroxicam-beta-CD and the addition of ternary alkaline agents were also found to be significant factors. The dissolution rate of the complexes formed using SCCO2 was found to be significantly higher than that of the physical mixture. Inclusion complexes have also been obtained with miconazole treating mixtures of miconazole, CDs and citric acid by SCCO2. This new technique of inclusion of poorly soluble drugs into CDs allows the preparation of solid complexes without using organic solvents and thus without residues. [less ▲]

Detailed reference viewed: 33 (5 ULg)