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See detailNumerical determination of 3D temperature fields in steel joints
Franssen, Jean-Marc ULg

in Fire & Materials (2004), 28(2-4, MAR-AUG), 63-82

A numerical study was undertaken to investigate the temperature field in steel joints and to compare the temperatures in the joints with the temperatures of the adjacent steel members on the hypothesis ... [more ▼]

A numerical study was undertaken to investigate the temperature field in steel joints and to compare the temperatures in the joints with the temperatures of the adjacent steel members on the hypothesis that the thermal protection is the same on the joint and in the members. Very brief information is given on the numerical model, supplemented with parametric studies made in order to determine the required level of discretization in the time and in the space domain. A simplified assumption for representing the thermal insulation is also discussed and validated. Different numerical analyses are performed, with a variation of the following parameters: (i) type of joints, from very simple to more complex configurations, with welds and/or bolts, all of them representing joints between elements located in the same plane; (ii) unprotected joints or protected by one sprayed material; (iii) ISO, hydrocarbon or one natural fire scenario. The fact that the thermal attack from the fire might be less severe because the joints are usually located in the corner of the compartment is not taken into account. Copyright (C) 2004 John Wiley Sons, Ltd. [less ▲]

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See detailSalmonella spp. in food of animal origin: a continuous threat for public health?
Korsak Koulagenko, Nicolas ULg; Clinquart, Antoine ULg; Daube, Georges ULg

in Annales de Médecine Vétérinaire (2004), 148(4), 174-193

Salmonella is a mesophilic bacterium that share common characteristics with Enterobacteriaceae. Two species are described: Salmonella enterica and Salmonella bongori. Beside the fact that the infection in ... [more ▼]

Salmonella is a mesophilic bacterium that share common characteristics with Enterobacteriaceae. Two species are described: Salmonella enterica and Salmonella bongori. Beside the fact that the infection in host cells requires type III secretion-systems, little is known, at present, about virulence mechanisms. Among the cultural detection methods, the use of semi-solid media seems more efficient than the others for Salmonella recovery. The techniques based on genetic amplification may be useful in order to further characterize the isolated strains. Salmonella can be isolated from the intestine of numerous animal species and its survival in the surroundings may be quite long. Several serotypes may cause clinical salmonellosis while others may be responsible for animal species of a carrier state. In this abstract, the influence of swine production system will be developed. The sustainable and ongoing surveillance are justified by the fact that Salmonella leads to numerous foodborne cases and outbreaks and is responsible of important economic and social costs. This surveillance aims to improve the sanitary quality of food from "farm to fork". The preventive methods available for the pre-harvest production step and for the slaughterhouse will be also evoked. [less ▲]

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See detailCase studies in measurement of random incidence scattering coefficients
Vorländer, Michael; Embrechts, Jean-Jacques ULg; De Geetere, Lieven et al

in Acta Acustica United With Acustica (2004), 90(5, SEP-OCT), 858-867

In this work measurements of random-incidence scattering coefficients in three laboratories are compared. The sample geometry is sinusoidal. These surfaces are geometrically identical, but they were ... [more ▼]

In this work measurements of random-incidence scattering coefficients in three laboratories are compared. The sample geometry is sinusoidal. These surfaces are geometrically identical, but they were constructed in different scales. So far, measurements of this kind were performed only in scale models. Using turntables in real sample size was hardly considered possible. One result of general importance is that measurements are indeed possible in real-scale reverberation rooms with turntables of 3 m diameter. There are only small differences between the real-scale and model-scale results. Some variations of the standard procedure were tested and the uncertainties identified: mounting of the sample, connection or sealing between sample and base plate, way of rotating the sample, air absorption and time variances. The results presented can be regarded as guidelines for application of ISO/DIS 17497-1. [less ▲]

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See detailParamagnetic reentrance of ac screening: Evidence of vortex avalanches in Pb thin films
Silhanek, Alejandro ULg; Raedts, S.; Moshchalkov, V. V.

in Physical Review. B : Condensed Matter (2004), 70(14),

We have studied the influence of a square array of pinning centers on the dynamics of vortex avalanches in Pb thin films by means of ac- and dc-magnetization measurements. Close to the superconducting ... [more ▼]

We have studied the influence of a square array of pinning centers on the dynamics of vortex avalanches in Pb thin films by means of ac- and dc-magnetization measurements. Close to the superconducting transition T-c, the commensurability between the vortex lattice and the pinning array leads to the well known local increments of the critical current. As temperature T decreases, matching features progressively fade out and eventually disappear. Further down in temperature, vortex avalanches develop and dominate the magnetic response. These avalanches manifest themselves as jumps in the dc magnetization and produce a lower ac shielding, giving rise to a paramagnetic reentrance in the ac screening chi(')(T). Within the flux-jump regime, two subregimes can be identified. Close to the boundary where vortex avalanches develop, the field separation between consecutive jumps follows the periodicity of the pinning array and a field- and temperature-dependent screening is observed. In this regime, the response also depends on frequency f in agreement with theoretical models for magnetothermal instabilities. At low enough temperatures and fields, the screening saturates to a constant value independent of T, H, and f, where jumps are randomly distributed. We have also found that vortex instabilities occupy a larger portion of the H-T diagram in patterned samples than in films without nanoengineered pinning sites. Finally, we discuss the possible origin of the vortex avalanches and compare our results with previous experimental and theoretical studies. [less ▲]

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See detailA Real-Time Grading Method Of Apples Based On Features Extracted From Defects
Leemans, Vincent ULg; Destain, Marie-France ULg

in Journal of Food Engineering (2004), 61(1),

This paper presents a hierarchical grading method applied to Jonagold apples. Several images covering the whole surface of the fruits were acquired thanks to a prototype grading machine. These images were ... [more ▼]

This paper presents a hierarchical grading method applied to Jonagold apples. Several images covering the whole surface of the fruits were acquired thanks to a prototype grading machine. These images were then segmented and the features of the defects were extracted. During a learning procedure, the objects were classified into clusters by k-mean clustering. The classification probabilities of the objects were summarised and on this basis the fruits were graded using quadratic discriminant analysis. The fruits were correctly graded with a rate of 73 %. The errors were found having origins in the segmentation of the defects or for a particular wound, in a confusion with the calyx end. [less ▲]

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See detailAntagonistic activity of yeast against post-harvest diseases of tropical fruits.
Jijakli, Haissam ULg; Lassois, Ludivine ULg; Lahlali, R.

in Bulletin des Séances de l’Académie Royale des Sciences d’Outre-Mer = Mededelingen der Zittingen van de Koninklijke Academie voor Overzeese Wetenschappen (2004), 50(2), 153-163

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See detailDevelopment of RT-PCR assays using fluorogenic-3 minor groove binder DNA probes for detection of fruit tree viruses.
Roussel, S.; Kummert, J.; Dutrecq, O. et al

in Acta Horticulturae (2004), 657(1),

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See detailInhibitory Action Of A New Lectin From Xerocomus Chrysenteron On Cell-Substrate Adhesion
Marty-Detraves, C.; Francis, Frédéric ULg; Baricault, L. et al

in Molecular and Cellular Biochemistry (2004), 258(1-2), 49-55

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See detailSampling protocols and risk of error significance in molecular detection tests for fruit trees certification.
Kummert, Jean; Malice, Marie ULg; Marbot, Sophie et al

in Acta Horticulturae (2004), (657), 541-546

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See detailSubtype Selective Substrates For Histone Deacetylases
Heltweg, B.; Dequiedt, Franck ULg; Marshall, Bl. et al

in Journal of Medicinal Chemistry (2004), 47(21),

To probe the steric requirements for deacylation, we synthesized lysine-derived small molecule substrates and examined structure-reactivity relationships with various histone deacetylases. Rat liver ... [more ▼]

To probe the steric requirements for deacylation, we synthesized lysine-derived small molecule substrates and examined structure-reactivity relationships with various histone deacetylases. Rat liver, human HeLa, and human recombinant class I and II histone deacetylases (HDACs) as well as human recombinant NAD(+)-dependent SIRT1 (class III enzyme) were used in these studies. A benzyloxycarbonyl substituent on the alpha-amino group yielded the highest conversion rates. Replacing the epsilon-acetyl group with larger lipophilic acyl substituents led to a pronounced decrease in conversion by class I and II enzymes; the class III enzyme displayed a greater tolerance. Incubations with recombinant FLAG-tagged human HDACs 1, 3, and 6 showed a distinct subtype selectivity among small molecule substrates. The subtype selectivity of HDAC inhibitors could be predicted with these substrates and an easily obtainable mixture of HDAC subtypes. [less ▲]

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See detailKinetics of engraftment in patients with hematologic malignancies given allogeneic hematopoietic cell transplantation after nonmyeloablative conditioning.
Baron, Frédéric ULg; Baker, Jennifer E.; Storb, Rainer et al

in Blood (2004), 104(8), 2254-62

We analyzed the kinetics of donor engraftment among various peripheral blood cell subpopulations and their relationship to outcomes among 120 patients with hematologic malignancies given hematopoietic ... [more ▼]

We analyzed the kinetics of donor engraftment among various peripheral blood cell subpopulations and their relationship to outcomes among 120 patients with hematologic malignancies given hematopoietic cell transplantation (HCT) after nonmyeloablative conditioning consisting of 2 Gy total body irradiation (TBI) with or without added fludarabine. While patients rapidly developed high degrees of donor engraftment, most remained mixed donor/host chimeras for up to 180 days after HCT. Patients given preceding chemotherapies and those given granulocyte colony-stimulating factor-mobilized peripheral blood mononuclear cell (G-PBMC) grafts had the highest degrees of donor chimerism. Low donor T-cell (P = .003) and natural killer (NK) cell (P = .004) chimerism levels on day 14 were associated with increased probabilities of graft rejection. High T-cell chimerism on day 28 was associated with an increased probability of acute graft-versus-host disease (GVHD) (P = .02). Of 93 patients with measurable malignant disease at transplantation, 41 achieved complete remissions a median of 199 days after HCT; 19 of the 41 were mixed T-cell chimeras when complete remissions were achieved. Earlier establishment of donor NK-cell chimerism was associated with improved progression-free survival (P = .02). Measuring the levels of peripheral blood cell subset donor chimerisms provided useful information on HCT outcomes and might allow early therapeutic interventions to prevent graft rejection or disease progression. [less ▲]

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See detailEffects of atmospheric turbulence on the GENIE nulling interferometer
Absil, Olivier ULg

in Aime, Claude; Soummer, Rémi (Eds.) Astronomy with High Contrast Imaging II (2004)

Two competitive design studies for the Ground-based European Nulling Interferometer Experiment (GENIE) have recently been initiated by the European Space Agency and the European Southern Observatory. A ... [more ▼]

Two competitive design studies for the Ground-based European Nulling Interferometer Experiment (GENIE) have recently been initiated by the European Space Agency and the European Southern Observatory. A major issue in these studies is the influence of atmospheric turbulence on the performance of the instrument, and how atmospheric effects can be compensated in order to reach the goal performance (detection of faint exozodiacal clouds). In this paper, we review the main atmospheric processes affecting a nulling interferometer and discuss possible ways to reduce them by means of real-time control systems. Preliminary performance estimates of GENIE are then presented. The effects of the thermal background and its fluctuations (Absil & Bakker 2004) are not considered here. [less ▲]

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See detailBias-variance tradeoff of soft decision trees
Olaru, Cristina; Wehenkel, Louis ULg

(2004)

This paper focuses on the study of the error composition of a fuzzy decision tree induction method recently proposed by the authors, called soft decision trees. This error may be expressed as a sum of ... [more ▼]

This paper focuses on the study of the error composition of a fuzzy decision tree induction method recently proposed by the authors, called soft decision trees. This error may be expressed as a sum of three types of error: residual error, bias and variance. The paper studies empirically the tradeoff between bias and variance in a soft decision tree method and compares it with the tradeoff of classical crisp regression and classification trees. The main conclusion is that the reduced prediction variance of fuzzy trees is the main reason for their improved performance with respect to crisp ones. [less ▲]

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See detailOperation rules determined by risk analysis for special protection systems at Hydro-Québec
Huang, Jinan; Vanier, Guy; Valette, Alain et al

(2004)

This paper describes a new approach used by Hydro-Québec to determine the rules of automatic devices installed in its main power plants to maintain secure operation under extreme contingencies. An example ... [more ▼]

This paper describes a new approach used by Hydro-Québec to determine the rules of automatic devices installed in its main power plants to maintain secure operation under extreme contingencies. An example of application of this approach is given to illustrate how to apply data mining technique for the rules of the automatic generator rejection and remote load shedding system (RPTC: Rejet de Production et Télédélestage de Charges in French) installed at the Churchill Falls hydroelectric power plant (5500 MW) in Labrador. Real time snapshots of the Hydro-Québec power system collected over several years data have been used to generate large amounts of results (database) by transient stability simulations. The database is processed by the data mining software developed by the University of Liege to construct the decision trees. This approach gives the most relevant parameters and finds optimal settings for the RPTC system at the Churchill Falls, minimizing the number of generator rejection while maintaining the same performance in terms of security coverage. New operation rules have thus been established. [less ▲]

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See detailWhither dynamic congestion management ?
Wehenkel, Louis ULg

(2004)

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See detailPreventive vs. emergency control of power systems
Wehenkel, Louis ULg; Pavella, Mania ULg

(2004)

A general approach to real-time transient stability control is described, yielding various complementary techniques: pure preventive, open loop emergency, and closed loop emergency controls. The ... [more ▼]

A general approach to real-time transient stability control is described, yielding various complementary techniques: pure preventive, open loop emergency, and closed loop emergency controls. The organization of the resulting control schemes is then revisited in order to make it able to cover static and voltage security, in addition to transient stability. Distinct approaches for preventive and emergency operating conditions are advocated. [less ▲]

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See detailA Set of Equity Indicators of the European Education Systems A synthesis
Demeuse, Marc; Baye, Ariane ULg; Straeten, Marie-Hélène et al

in Moreno Herrera, L.; Francia, G. (Eds.) Educational Policies. Implications for Equity, Equality and Equivalence (2004)

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See detailThe evolution of inorganic chlorine above the Jungfraujoch station: an update.
Mahieu, Emmanuel ULg; Duchatelet, Pierre ULg; Zander, Rodolphe ULg et al

in Zerefos, C. S. (Ed.) Proceedings of the 20th Quadrennial Ozone Symposium (2004)

Within the frame of the NDSC, the total vertical column abundances of HCl and ClONO2, by far the two most important inorganic chlorine reservoirs at northern mid-latitudes, have been further monitored ... [more ▼]

Within the frame of the NDSC, the total vertical column abundances of HCl and ClONO2, by far the two most important inorganic chlorine reservoirs at northern mid-latitudes, have been further monitored above the Jungfraujoch station (Swiss Alps, 46.5ºN, 8.0ºE, 3580m a.s.l.), by analyzing infrared solar absorption spectra recorded with very high-resolution Fourier spectrometers. The mean temporal evolution of the sum of their monthly mean abundance time series indicates that the total stratospheric inorganic chlorine loading (Cly) has decreased slowly (-0.7+/-0.3%/yr, 1-sigma) since it peaked in late 1996, at the limit of being statistically significant at the 2-sigma level. Comparison with model calculations and with the evolution of surface total organic chlorine will also be discussed. [less ▲]

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See detailGround-based FTIR measurements of O3- and climate-related gases in the free troposphere and lower stratosphere
De Mazière, M.; Barret, B.; Vigouroux, C. et al

in Zerefos, C. S. (Ed.) Proceedings Quadrennial Ozone Symposium (2004)

In the frame of the EC project UFTIR (Time series of Upper Free Troposphere observations from a European ground-based FTIR network), a common strategy for an optimal determination of the chemical ... [more ▼]

In the frame of the EC project UFTIR (Time series of Upper Free Troposphere observations from a European ground-based FTIR network), a common strategy for an optimal determination of the chemical composition in the free troposphere and lower stratosphere with ground-based Fourier-transform infrared (FTIR) spectrometers is being developed. The project focuses on 6 target species that are O3, CO, CH4, N2O, C2H6 and CHClF2 (HCFC-22). The strategy consists in selecting the most appropriate parameters to retrieve vertical concentration profiles from solar FTIR spectra. Among the important parameters are the spectral microwindows: they have been optimised to maximise the information content and to minimize the influence of poorly known spectroscopic data and interfering species. [less ▲]

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