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See detailComparison between a high chromium steel and a semi HSS grades used as work rolls in the roughing stands of a hot strip mill
Tchuindjang, Jérôme Tchoufack ULg; Lecomte-Beckers, Jacqueline ULg

in Proceedings of The 10th International Conference on Steel Rolling (10th ICSR) (2010, September)

Two alloys grades for work rolls used in the roughing stand of Hot Strip Mill (HSM) were compared. The first grade known as High Chromium Steel (HCS) is actually the alloy widely used for such an ... [more ▼]

Two alloys grades for work rolls used in the roughing stand of Hot Strip Mill (HSM) were compared. The first grade known as High Chromium Steel (HCS) is actually the alloy widely used for such an application, while the second one known as semi-High Speed Steel (semi-HSS) is the new grade developed to improve overall properties of the work roll in the roughing stands of the HSM. In the present work, the new semi-HSS grade is studied starting from 3 chemical compositions closed one to another, the variation in the alloying elements being intended to assess, on one hand the effect of a light increase of the carbon content, and on the other hand the influence of the addition of a strong MC carbide forming element. The comparison of HCS and semi-HSS grades involved many fields. Regarding the metallurgical aspect, such a comparison led to the enhancement of the solidification range, the crystallization behavior and the microstructure in the as-cast condition for both grades. Heat treatment behavior of both grades was also investigated and optimal parameters leading to the homogenization of the alloy composition within the deepness of the roll were found. Furthermore, hot corrosion behavior and performances of the work rolls in service were compared. Various techniques were used in order to characterize both grades, such as Differential Thermal Analysis (to determine phase transformations temperatures, the crystallization behavior and the interval of solidification), hardness measurements, optical microscopy, scanning electron microscopy associated with energy dispersive X ray spectroscopy (to determine the nature and the composition of phases, especially matrix and carbides). Finally micro-macro relations between the nature of the microstructure and the properties of HCS and semi-HSS rolls grades in service conditions could be established. [less ▲]

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See detailComparison between active and passive surveillance within the Network of Epidemiological Surveillance of Animal Diseases in Chad (REPIMAT)
Ouagal, M.; Hendrikx, P.; Saegerman, Claude ULg et al

in Acta Tropica (2010), 116(2), 147-151

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See detailComparison between Alprazolam and Hydroxyzine for Oral Premedication
Franssen, Colette ULg; Hans, Pol ULg; Brichant, Jean-François ULg et al

in Canadian Journal of Anaesthesia = Journal Canadien d'Anesthésie (1993), 40(1), 13-7

The safety and efficacy of alprazolam and hydroxyzine administered orally as surgical premedicants were compared in a double-blind controlled study. Sixty-five patients were given either alprazolam 1 mg ... [more ▼]

The safety and efficacy of alprazolam and hydroxyzine administered orally as surgical premedicants were compared in a double-blind controlled study. Sixty-five patients were given either alprazolam 1 mg or hydroxyzine 75 mg, one to two hours before surgery. Anxiety was assessed by both the patient and the anaesthetist, the patient using a visual analogue scale, the anaesthetist employing both analogue and ordinal ratings. Sedation was assessed by the anaesthetist only, using the same two methods. Amnesia was appraised with a simple memory test. Safety was assessed by recording adverse effects and measuring haemodynamic variables. Premedication with alprazolam produced a modest reduction in anxiety (28%) (P < 0.01) while hydroxyzine had no detectable effect. The comparison of the sedation level and of the memory test revealed no difference between the two premedicants. Minor side effects were only observed in the hydroxyzine group. Changes in blood pressure were more pronounced in the hydroxyzine group. This study shows that alprazolam and hydroxyzine are safe and efficient oral premedicants. However, alprazolam is preferable to hydroxyzine in terms of anxiolytic and adverse effects. [less ▲]

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See detailComparison between analytical and optimal control techniques in the differential drag based rendez-vous
Dell'Elce, Lamberto ULg; Kerschen, Gaëtan ULg

in Proceedings of the 5th International Conference on Spacecraft Formation Flying Missions & Technologies (2013, May 29)

The focus of this study is on differential drag for propellantless satellite rendez-vous. This technique is particularly attractive for low-Earth-orbit small satellites for which stringent weight ... [more ▼]

The focus of this study is on differential drag for propellantless satellite rendez-vous. This technique is particularly attractive for low-Earth-orbit small satellites for which stringent weight constraints apply. Most existing contributions are based on bang-bang strategies, which may be difficult to implement in practice. This is why the present paper proposes a novel strategy integrating pseudospectral optimal control for maneuver planning and model predictive control for dealing with uncertainties and unmodeled dynamics. One important advantage of this methodology is that it can naturally account for attitude dynamics and constraints, which, in turn, paves the way for the practical realization of differential drag-based rendez-vous. A realistic scenario involving two nanosatellites of the QB50 constellation is considered to illustrate and validate the proposed developments. In addition, a comparison of this numerical technique with an existing analytic solution is carried out, and their respective pros and cons are discussed. [less ▲]

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See detailComparison between blood serum and salivary cortisol concentrations in horses using an adrenocorticotropic hormone challenge
Peeters, Marie ULg; Sulon, Joseph; Beckers, Jean-François ULg et al

in Equine Veterinary Journal (2011), 43(4), 487-493

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See detailComparison between co-crystallisation properties of POP and OPP
Danthine, Sabine ULg; tirtiaux, a; wouters, j et al

Poster (2004)

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See detailcomparison between co-crystallisation properties of POP and OPP : a tool to understand industrial processes
gibon, Véronique; tirtiaux, alain; Danthine, Sabine ULg et al

Poster (2004, November)

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See detailComparison between column switching and SPE on disposable cartridges in the automatic determination of indomethacin in plasma by HPLC
Hubert, Philippe ULg; Renson, M.; Gerardy-Moies, C. et al

in Journal de Pharmacie de Belgique (1992), 47

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See detailComparison between Conodont Zonation and Spore Assemblages at the Devonian-Carboniferous Boundary in the Western and Central United States and in Europe.
Sandberg, C.A.; Streel, Maurice ULg; Scott, R.A.

in . Compte Rendu 7ème Congres International de Stratigraphie et de Géologie du Carbonifère. Krefeld 1971 (1972)

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See detailCOMPARISON BETWEEN CONTINUOUS AND BATCH PROCESSING TO PRODUCE XYLANASE BY Penicillium canescens 10-10c
Bakri, Y.; Akeed, Y.; Thonart, Philippe ULg

in Brazilian Journal of Chemical Engineering (2012), 29(3), 441-447

Penicillium canescens 10-10c strain was cultivated on barley straw hydrolysate as a soluble nutrient source and as inducer for xylanase production. Barley straw hydrolysate was obtained by treatment of ... [more ▼]

Penicillium canescens 10-10c strain was cultivated on barley straw hydrolysate as a soluble nutrient source and as inducer for xylanase production. Barley straw hydrolysate was obtained by treatment of barley straw with NaOH or hot water. In shake flask cultures, NaOH treatment was found to increase the biomass production, but was not accompanied by an increase in xylanase production. The best xylanase production (54 U/ml) was observed on hydrolyzed extract from barley straw treated with hot water (100 ºC) for 3 hours. Enzyme production was further improved by scaling up the cultivation process to a 3-L stirred tank bioreactor. For batch cultivations in the bioreactor, the maximum xylanase productivity reached 1.31 and 0.46 U/ml/h, respectively, after 96 and 168 hours of cultivation. However, xylanase productivity reached 3.46 U/ml/h in the continuous culture. These results suggest that xylanase can be produced efficiently by Penicillium canescens 10-10c in continuous culture from an inexpensive source such as barley straw hydrolysate. [less ▲]

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See detailComparison between culture of bovine embryos in vitro versus development in rabbit oviducts and in vivo
Ectors, Fabien ULg; Thonon, Fabienne; Delval, Alain et al

in Livestock Production Science (1993), 36

The aim of this work was to evaluate the efficiency of different embryo culture methods for in vitro embryo production: development in co-culture with bovine oviductal epithelial cells (BOEC), in BOEC ... [more ▼]

The aim of this work was to evaluate the efficiency of different embryo culture methods for in vitro embryo production: development in co-culture with bovine oviductal epithelial cells (BOEC), in BOEC conditioned medium (CM) or in rabbit oviducts, versus in vivo produced embryos. There was no significant difference in terms of percentages of cleaved and 8-cell stages obtained between CM and BOEC. In CM, 24.8% of the cleaved embryos became blastocysts. In BOEC, 14.5% of the cleaved embryos became blastocysts. Among the 190 zygotes transferred in the rabbit oviducts, 127 have been recovered 5 days later, and 17.4% became blastocysts. There was no significant difference in term of blastocyst formation between the development in rabbit and in BOEC. However, there was a significant difference between the CM group and the two other groups. The numbers of cells in blastocysts from different sources were investigated: in vivo blastocysts contained 107 cells assumed to be 100%, in vitro blastocysts developed in rabbit oviduct 100.1 cells (93.3%), BOEC blastocysts 90.8 cells (84.6%) and CM blastocysts 72.3 cells (67.3%). This study confirmed earlier works on the oviduct effect on blastocyst quality in terms of development rate and cell number. [less ▲]

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See detailComparison between different methods of measurement of momentum and sensible heat fluxes over canopies.
Aubinet, Marc ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (1997), 1(1),

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See detailComparison between EC3 and the original proposal for Beam-Columns in Case of Fire
Talamona, D.; Lopes, N.; Vila Real, P. et al

in Ofner (Ed.) Proceedings of the 5th European Conference on Steel and Composite Structures (EUROSTEEL 2008) (2008)

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See detailA Comparison Between Explicit and Implicit Modelling of Transient Creep Strain in Concrete Uniaxial Constitutive Relationships
Gernay, Thomas ULg; Franssen, Jean-Marc ULg

in Proceedings of the Fire and Materials 2011 Conference (2011, February)

Transient creep strain has to be included within the constitutive relationships for concrete at high temperatures. However, the necessity of taking into account this term explicitly is not clearly defined ... [more ▼]

Transient creep strain has to be included within the constitutive relationships for concrete at high temperatures. However, the necessity of taking into account this term explicitly is not clearly defined. In the Eurocode 2 uniaxial concrete material model, transient creep is included implicitly. This paper aims to highlight the capabilities and limitations of concrete uniaxial models at elevated temperatures for thermo-mechanical behaviour modelling, depending on the implicit or explicit consideration of transient creep strain in the model. The characteristics inherent to the two types of models are described and compared. It appears that one of the major limitations of implicit models concerns the unloading stiffness because implicit models treat transient creep as reversible. Based on numerical analysis performed on loaded concrete columns subjected to natural fire, it is shown that the stress-temperature paths experienced by structural concrete are varied and complicated and that concrete material models cannot handle properly these complex situations of unsteady temperatures and stresses without explicit consideration of transient creep. The paper proposes a new formulation of the Eurocode 2 concrete material model that contains an explicit term for transient creep. The new model is implemented in the software SAFIR and validated against experimental data of the mechanical strain developed by concrete cylinders under different unsteady temperatures and loads. It is shown that the actual material behaviour is better matched with the new explicit model than with the current implicit Eurocode 2 model. Finally, a comparison is given between experimental and calculated results on an axially restrained concrete column subjected to heating and cooling. [less ▲]

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See detailComparison between finite element calculations and holographic interferometry measurements, of the thermo-mechanical behaviour of satellite structures in composite materials
Thizy, Cédric ULg; Lemaire, Philippe ULg; Georges, Marc ULg et al

in Zhang, G.; Kip, D.; Nolte, D. (Eds.) et al Photorefractive Effects, Materials, and Devices (2005, July)

The stability requirements for the satellite structures evolve increasingly. To predict this one during the design phase a more and more used tool is the finite element calculation of thermo-elastic ... [more ▼]

The stability requirements for the satellite structures evolve increasingly. To predict this one during the design phase a more and more used tool is the finite element calculation of thermo-elastic models. The verification by measurement of these predictions on operational systems or testing rods is a key element allowing to validate these calculations and also to improve the simulations in order to study more complex cases in a reliable manner. We present the results of such a comparative study carried out on prototype structures using dynamic holographic interferometry, based on a sillenite photorefractive crystal, to measure the thermo-mechanical behavior [less ▲]

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See detailA comparison between five structural fire codes applied to steel elements
Franssen, Jean-Marc ULg; Schleich, Jean-Baptiste; Cajot, Louis-Guy et al

in Proceedings Fourth International Symposium on Fire Safety Science (1994)

Five codes have been used to simulate the fire behaviour of steel structural elements subjected to fire and the results have been compared. There is no coparison with experimental results.

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See detailA comparison between FUV remote sensing of magnetotail stretching and the T01 model during quiet conditions and growth phases
Blockx, Caroline ULg; Gérard, Jean-Claude ULg; Coumans, Valérie ULg et al

in Annales Geophysicae [= ANGEO] (2007), 25(1), 161-170

In a previous study, Blockx et al. (2005) showed that the SI12 camera on board the IMAGE spacecraft is an excellent tool to remotely determine the position of the isotropy boundary (IB) in the ionosphere ... [more ▼]

In a previous study, Blockx et al. (2005) showed that the SI12 camera on board the IMAGE spacecraft is an excellent tool to remotely determine the position of the isotropy boundary (IB) in the ionosphere, and thus is able to provide a reasonable estimate of the amount of stretching of the magnetic field lines in the magetotail. By combining an empirical model of the magnetospheric configuration with Sergeev's criterion for non-adiabatic motion, it is also possible to obtain a theoretical position of IB in the ionosphere, for known conditions in the solar wind. Earlier studies have demonstrated the inadequacy of the Tsyganenko-1989 (T89) model to quantitatively reproduce the field line stretching, particularly during growth phases. In this study, we reexamine this question using the T01 model which considers the time history of the solar wind parameters. We compare the latitude of IB derived from SI12 global images near local midnight with that calculated from the T01 model and the Sergeev's criterion. Observational and theoretical results are found to frequently disagree. We use in situ measurements of the magnetic field with the GOES-8 satellite to discriminate which of the two components in the calculation of the theoretical position of the IB (the T01 model or Sergeev's criterion) induces the discrepancy. For very quiet magnetic conditions, we find that statistically the T01 model approximately predicts the correct location of the maximum proton precipitation. However, large discrepancies are observed in individual cases, as demonstrated by the large scatter of predicted latitudes. For larger values of the AE index, the model fails to predict the observed latitude of the maximum proton intensity, as a consequence of the lack of consideration of the cross-tail current component which produces a more elongated field configuration at the location of the proton injection along the field lines. We show that it is possible to match the observed location of the maximum proton precipitation by decreasing the current sheet half-thickness D parameter. We thus conclude that underestimation of the field line stretching leads to inadequately prediction of the boundary latitude of the non-adiabatic proton precipitation region. [less ▲]

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