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See detailA Methodology to Improve the Robustness of Gas Turbine Engine Performance Monitoring Against Sensor Faults
Dewallef, Pierre ULg; Borguet, Sébastien ULg

in Journal of Engineering for Gas Turbines and Power (2013), 135(5),

For turbine engine performance monitoring purposes, system identification techniques are often used to adapt a turbine engine simulation model to some measurements performed while the engine is in service ... [more ▼]

For turbine engine performance monitoring purposes, system identification techniques are often used to adapt a turbine engine simulation model to some measurements performed while the engine is in service. Doing so, the simulation model is adapted through a set of so-called health parameters whose values are intended to represent a faithful image of the actual health condition of the engine. For sake of low computational burden, the problem of random errors contaminating the measurements is often considered to be zero-mean, white and Gaussian random variables. However, when a sensor fault occurs, the measurement errors no longer satisfy the Gaussian assumption and the results given by the system identification rapidly become unreliable. The present contribution is dedicated to the development of a diagnosis tool based on a Kalman filter whose structure is slightly modified in order to accommodate sensor malfunctions. The benefit in terms of the diagnostic reliability of the resulting tool is illustrated on several sensor faults that may be encountered on a current turbofan layout. [less ▲]

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See detailMethods
Richelle, Marc ULg; Lejeune, Helga ULg; Mantanus, H. et al

in Richelle, Marc; Lejeune, Helga (Eds.) Time in animal behaviour (1980)

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See detailMethods and means for metabolic engineering and improved product formation by micro-organisms
Rigali, Sébastien ULg; Titgemeyer, Fritz; van Wezel, Gilles

Patent (2007)

Detailed reference viewed: 16 (0 ULg)
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See detailMethods for Estimating Areas under Receiver-Operating Characteristic Curves: Illustration with Somatic-Cell Scores in Subclinical Intramammary Infections
Detilleux, Johann ULg; Arendt, J.; Lomba, F. et al

in Preventive Veterinary Medicine (1999), 41(2-3), 75-88

The aim of this study was to demonstrate receiver-operating characteristic (ROC) methodology in the context of bovine intramammary infection (IMI). Quarter somatic cell scores (SCS) were available to ... [more ▼]

The aim of this study was to demonstrate receiver-operating characteristic (ROC) methodology in the context of bovine intramammary infection (IMI). Quarter somatic cell scores (SCS) were available to evaluate quarter IMI, and the final IMI diagnosis was made from milk bacteriologic cultures. Data consisted of 11,453 quarter-milk samples collected on 2084 clinically healthy cows located in 154 Belgian herds. Bacteriological analyses showed 16.2%, 7.2%, and 11.9% of quarters infected with coagulase-positive Staphylococcus spp., Streptococcus agalactiae, and coagulase-negative Staphylococcus spp., respectively. The ROC curve indicated all the combinations of sensitivity and specificity that quarter SCS was able to provide as a test to identify quarter IMI. Among parametric, semi-parametric, and non-parametric methods to estimate area under ROC curves, the parametric method seemed the least appropriate for analyzing SCS in this study. With the non-parametric method, the total area under the ROC curves showed quarter SCS could identify quarter IMI with an overall accuracy of 69%, 76%, and 59% for coagulase-positive Staphylococcus spp., S. agalactiae, and coagulase-negative Staphylococcus spp., respectively. Parametric and non-parametric statistical tests showed that overall SCS diagnostic capability was significantly (p<0.01) different from chance and was different (p<0.01) across the three bacteria. However, the SCS thresholds yielding the highest percentage of quarters correctly classified as infected (for the observed prevalence and for equal costs assigned to false-positive and false-negative results) were so high that they had no practical value. The major advantage of ROC analysis is the comprehensive description of the discrimination capacity of SCS for all possible choices of critical values. The major disadvantage is the dependency upon the gold standard used for the final diagnosis--but recent improvements of the methodology will correct the problem. [less ▲]

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See detailMethods for size classification of wood chips
Hartmann, Hans; Böhm, Thorsten; Daugbjerg Jensen, Peter et al

in Biomass & Bioenergy (2006)

Methods for size classification of wood chips were analysed in an international round robin using 13 conventional wood chip samples and two specially prepared standard samples, one from wood chips and one ... [more ▼]

Methods for size classification of wood chips were analysed in an international round robin using 13 conventional wood chip samples and two specially prepared standard samples, one from wood chips and one from hog fuel. The true size distribution of these two samples (according to length, width and height) had been determined stereometrically (reference method) using a digital calliper gauge and by weighing each of the about 7000 wood particles per sample. Five different horizontal and three rotary screening devices were tested using five different screen hole diameters (3.15, 8, 16, 45, 63 mm, round holes). These systems are compared to a commercially available continuously measuring image analysis equipment. The results show that among the devices of a measuring principle—horizontal and rotary screening—the results are quite comparable, while there is a severe incompatibility when distributions are determined by different measuring principles. Highest conformity with the reference values is given for measurements with an image analysis system, whereas for all machines with horizontal screens the median value of the size distribution only reached between one-third to half of the reference median value for the particle length distribution. These deviations can be attributed to a higher particle misplacement, which is particularly found in the larger fractions. Such differences decrease when the particle’s shape is more roundish (i.e. sphericity closer to one). The median values of length distributions from screenings with a rotary classifier are between the measurements from an image analysis and horizontal screening devices. [less ▲]

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See detailMethods for the preparation of bimetallic xerogel catalysts designed for chlorinated wastes processing
Lambert, Stéphanie ULg; Ferauche, Fabrice; Heinrichs, Benoît ULg et al

in Journal of Non-Crystalline Solids (2006), 352(26-27), 2751-2762

The aim of this work is to simplify and generalize the synthesis procedure of bimetallic supported catalysts by sol-gel process. For Pd-Ag/SiO2, co-gelled xerogels catalysts a number of synthesis ... [more ▼]

The aim of this work is to simplify and generalize the synthesis procedure of bimetallic supported catalysts by sol-gel process. For Pd-Ag/SiO2, co-gelled xerogels catalysts a number of synthesis procedures were compared: use of one or two specific alkoxides able to form a chelate with palladium and/or silver cations, reagent mixing in one or two steps, use of industrial grade chemicals instead of laboratory grade chemicals. The catalysts obtained are quite similar: same metal dispersion, same tailored morphology, same localization and accessibility of Pd-Ag alloy nanoparticles inside microporous silica, same activity and selectivity for hydrodechlorination of 1,2-dichloroethane into ethylene. For catalyst production at large scale the synthesis can be achieved in one step with 3-(2-aminoethyl)aminopropyltrimethoxysilane of industrial grade as chelating alkoxide, tetraethylorthosilicate (TEOS) of industrial grade and ethanol denatured with diethyl phthalate. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailMethods for Vitamin D measurement - analytical problems and clinical relevance
Cavalier, Etienne ULg

Conference (2010, March 05)

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See detailMethods in social cognition research
Dardenne, Benoît ULg

Scientific conference (1992)

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See detailMethods of clinical and biological assessment of rheumatoid arthritis
Malaise, Michel ULg; Franchimont, P.

in Scandinavian Journal of Rheumatology. Supplement (1987), 65

Inflammation has long been recognised as notoriously difficult to measure both in clinical practice and in the laboratory. Of all the cardinal features of inflammation, pain relief is really what the ... [more ▼]

Inflammation has long been recognised as notoriously difficult to measure both in clinical practice and in the laboratory. Of all the cardinal features of inflammation, pain relief is really what the patients want, and among disabled persons, rheumatic patients are the only ones who must cope with chronic pain. The rheumatologist, however, is also interested in other parameters that are thought to reflect improvement of the inflammatory process. The methods used to clinically assess rheumatoid arthritis (RA) should share the following four parameters: validity, sensitivity, reliability and simplicity. Unfortunately, at present, no single ideal method is capable of accurately reflecting disease activity in RA. The measurement of pain relief by the visual analogue scale, the determination of the Ritchie index and the duration of morning stiffness, plus patient assessment of global response should be enough to detect clinical activity of the drug in RA. If we are working with slow-acting drugs or so-called disease modifying antirheumatic drugs (DMARDs), it should be appropriate to include X-ray analysis and laboratory tests in the evaluation. A reduction in the number of fresh erosions and/or the healing of present erosions can give reliable information on the capacity of the drug to really modify the course of the disease. At present, measurement of the erythrocyte sedimentation rate and of acute phase serum proteins seems to offer the best available assessment during early weeks of therapy. The other biological tests are of limited value in reflecting or predicting a beneficial clinical response to DMARDs. [less ▲]

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See detailMethods of sensory evaluation of odour and 50 m3 test facility at Arlon laboratory
Romain, Anne-Claude ULg; Nicolas, Jacques ULg; Degraeve, Ch

Diverse speeche and writing (2008)

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See detailMethods of sputum processing for cell counts, immunocytochemistry and in situ hybridisation
Efthimiadis, A.; Spanevello, A.; Hamid, Q. et al

in European Respiratory Journal (2002), 20(Suppl. 37), 19-23

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See detailMethods to Increase the Robustness of Finite-Volume Flow Models in Thermodynamic Systems
Quoilin, Sylvain ULg; Bell, Ian ULg; Desideri, Adriano ULg et al

in Energies (2014), 7(3), 1621-1640

This paper addresses the issues linked to simulation failures during integration in finite-volume flow models, especially those involving a two-phase state. This kind of model is particularly useful when ... [more ▼]

This paper addresses the issues linked to simulation failures during integration in finite-volume flow models, especially those involving a two-phase state. This kind of model is particularly useful when modeling 1D heat exchangers or piping, e.g., in thermodynamic cycles involving a phase change. Issues, such as chattering or stiff systems, can lead to low simulation speed, instabilities and simulation failures. In the particular case of two-phase flow models, they are usually linked to a discontinuity in the density derivative between the liquid and two-phase zones. In this work, several methods to tackle numerical problems are developed, described, implemented and compared. In addition, methods available in the literature are also implemented and compared to the proposed approaches. Results suggest that the robustness of the models can be significantly increased with these different methods, at the price of a small increase of the error in the mass and energy balances. [less ▲]

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See detailMethods to study protein aggregation and amyloid formation
Dumoulin, Mireille ULg; Bader, R.

in Protein & Peptide Letters (2006), 13

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See detailLe méthotrexate en rhumatologie: une révolution thérapeutique
Kaye, O.; Ribbens, Clio ULg; Hauwaert, Christian ULg et al

in Revue Médicale de Liège (1995), 50(11), 453-457

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See detailMethyl Oleate Modulates Lip2 Expression In The Lipolytic Yeast Yarrowia Lipolytica
Fickers, Patrick; Destain, Jacqueline ULg; Thonart, Philippe ULg

in Biotechnology Letters (2005), 27(22),

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See detailMethyl-laudanosine: A new pharmacological tool to investigate the function of small-conductance Ca2+-activated K+ channels
Scuvée-Moreau, Jacqueline ULg; Liégeois, Jean-François ULg; Massotte, Laurent ULg et al

in Journal of Pharmacology and Experimental Therapeutics (The) (2002), 302(3), 1176-1183

Small-conductance Ca(2+)-activated K(+) channels (SK channels) underlie the prolonged postspike afterhyperpolarization (AHP) observed in many central neurons and play an important role in modulating ... [more ▼]

Small-conductance Ca(2+)-activated K(+) channels (SK channels) underlie the prolonged postspike afterhyperpolarization (AHP) observed in many central neurons and play an important role in modulating neuronal activity. However, a lack of specific and reversible blockers of these channels hampers their study in various experimental conditions. Because previous work has shown that bicuculline salts block these channels, we examined whether related alkaloids, namely laudanosine quaternary derivatives, would produce similar effects. Intracellular recordings were performed on rat midbrain dopaminergic neurons and hippocampus CA1 pyramidal cells. Binding experiments were performed on rat cerebral cortex membranes. Laudanosine, methyl-laudanosine, and ethyl-laudanosine blocked the apamin-sensitive AHP of dopaminergic neurons with mean IC(50) values of 152, 15, and 47 microM, respectively. The benzyl and butyl derivatives were less potent. Methyl-laudanosine had no effect on the I(h) current, action potential parameters, or membrane resistance of dopaminergic cells, or on the decrease in input resistance induced by muscimol, indicating a lack of antagonism at GABA(A) receptors. Interestingly, 100 microM methyl-laudanosine induced a significant increase in spiking frequency of dopaminergic neurons but not of CA1 pyramidal cells, suggesting the possibility of regional selectivity. Binding experiments on laudanosine derivatives were in good agreement with electrophysiological data. Moreover, methyl-laudanosine has no affinity for voltage-gated potassium channels, and its affinity for SK channels (IC(50) 4 microM) is superior to its affinity for muscarinic (IC(50) 114 microM) and neuronal nicotinic (IC(50) > or =367 microM) receptors. Methyl-laudanosine may be a valuable pharmacological tool to investigate the role of SK channels in various experimental models. [less ▲]

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See detailMethylation analysis of the imprinted DLK1-GTL2 domain supports the random parental origin of the IGH-involving del(14q) in B-cell malignancies.
Katrincsakova, Beata; Takeda, Haruko ULg; Urbankova, Helena et al

in Epigenetics : Official Journal of the DNA Methylation Society (2009), 4(7), 469-75

Leukemias/lymphomas with IGH-involving del(14q)(1) commonly lose the DLK1-GTL2 imprinted domain that comprises several paternally and maternally expressed genes, including a cluster of microRNAs. Given ... [more ▼]

Leukemias/lymphomas with IGH-involving del(14q)(1) commonly lose the DLK1-GTL2 imprinted domain that comprises several paternally and maternally expressed genes, including a cluster of microRNAs. Given that deletion of this region could lead to inactivation of a monoallelically expressed tumor suppressor gene, our study aimed at determination of the parental origin of del(14q/IGH). The designed allele-specific methylation study of the DLK1/GTL2 intergenic differentially methylated region allowed us to determine the parental origin of del(14q/IGH) in 9/20 analyzed cases. In six cases del(14q/IGH) was of the paternal origin and in three cases of the maternal origin. These findings argue against the concept that a TSG/anti-oncomir located in the imprinted region is systematically inactivated by a targeted deletion of its functional allele. [less ▲]

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See detailMethylene blue: An old-timer or a compound ready for revival?
Donati, A.; Preiser, Jean-Charles ULg

in Critical Care Medicine (2006), 34(11), 2862-2863

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See detailMethylmercury and selenium in vitro effects on harbor seal (Phoca vitulina) lymphocytes : a multidisciplinary approach
Dupont, Aurélie ULg; Bouquegneau, Jean-Marie ULg; Das, Krishna ULg et al

Poster (2010, May 26)

Methylmercury (MeHg) bioaccumulates along the food web, leading to the highest levels in tissues of predatory species. It constitutes the predominant form present in the blood of marine mammals. The blood ... [more ▼]

Methylmercury (MeHg) bioaccumulates along the food web, leading to the highest levels in tissues of predatory species. It constitutes the predominant form present in the blood of marine mammals. The blood cells, including the immune cells, are therefore exposed to the toxic properties of that chemical. Nevertheless, selenium (Se) is an essential element absorbed concomitantly to MeHg which seems to modulate this toxicity. The goal of this study is to evaluate the immunotoxicity of MeHg on the harbor seal (Phoca vitulina) T lymphocytes, highly important in the adaptive immune response, and to investigate the modulating effect of Se on that toxicity. In parallel, the concentrations of MeHg, total mercury (T-Hg) and Se are determined in free-ranging harbour seal blood in order to follow their contamination levels. The T lymphocytes were isolated from the whole blood, exposed to various MeHg and Se concentrations and the exposure effects were estimated by functional tests including the evaluation of viability, proliferation, metabolic activity, DNA and protein synthesis, and by morphological analysis by transmission electron microscopy. The mean T-Hg concentration was 172 ± 143 µg/l of whole blood. The T lymphocytes cultures in vitro displayed a decreasing number of viable cells with increasing concentrations of MeHg, and numerous ultrastructural defects. The cells exposed to MeHg notably displayed distortion of the plasmic membrane, nucleus fragmentations, chromatin compaction, swelling mitochondrias and cytoplasmic vacuolisations. Those results highlighted various immunotoxic effects of MeHg, both at the functional and ultrastructural levels. The antagonistic role of Se on MeHg immunotoxicity is discussed. [less ▲]

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