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Peer Reviewed
See detailBulbospinal neuronopathy.
Schoenen, Jean ULiege; Delwaide, P. J.; Legros, J. J. et al

in Neurology (1992)

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See detailBulk and grain strain measurements in sandstone by image analysis
VanBrabant, Yves; Lebrun, Vincent; Nivart, Jean-François et al

in Proceedings of GeoVision 99 (1999)

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See detailBulk high-Tc superconductors with drilled holes: how to arrange the holes to maximize the trapped magnetic flux?
Lousberg, Grégory ULiege; Ausloos, Marcel ULiege; Vanderbemden, Philippe ULiege et al

in Superconductor Science and Technology (2008), 21

Drilling holes in a bulk high-Tc superconductor enhances the oxygen annealing and the heat exchange with the cooling liquid. However, drilling holes also reduces the amount of magnetic flux that can be ... [more ▼]

Drilling holes in a bulk high-Tc superconductor enhances the oxygen annealing and the heat exchange with the cooling liquid. However, drilling holes also reduces the amount of magnetic flux that can be trapped in the sample. In this paper, we use the Bean model to study the magnetization and the current line distribution in drilled samples, as a function of the hole positions. A single hole perturbs the critical current flow over an extended region that is bounded by a discontinuity line, where the direction of the current density changes abruptly. We demonstrate that the trapped magnetic flux is maximized if the centre of each hole is positioned on one of the discontinuity lines produced by the neighbouring holes. For a cylindrical sample, we construct a polar triangular hole pattern that exploits this principle; in such a lattice, the trapped field is ∼20% higher than in a squared lattice, for which the holes do not lie on discontinuity lines. This result indicates that one can simultaneously enhance the oxygen annealing, the heat transfer and maximize the trapped field. [less ▲]

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See detailBulk high-temperature superconducting hollow cylinders used for magnetic shielding: effect of an initial trapped field on the shielding performances.
Wera, Laurent ULiege; Fagnard, Jean-François ULiege; Hogan, Kevin ULiege et al

Poster (2016, November 09)

Bulk High-Temperature Superconductors (HTS) can be used as efficient passive magnetic shields with performances exceeding those of conventional ferromagnetic materials. The most common geometry for a ... [more ▼]

Bulk High-Temperature Superconductors (HTS) can be used as efficient passive magnetic shields with performances exceeding those of conventional ferromagnetic materials. The most common geometry for a superconducting shield is a bulk hollow cylinder. In this work, we investigate the magnetic shielding properties when the tube is not in the virgin state. Such a situation happens in practice when the tube has been initially subjected to a first magnetic field. The induced superconducting currents that are flowing in the tube generate a trapped magnetic moment which may deteriorate the shielding of a second field. Here we study experimentally how an initial trapped moment affects the shielding of a magnetic field, when they are both perpendicular to each other. In particular, we focus on the effect of an axial trapped moment on the transverse shielding performances and on the effect of a transverse trapped field on the axial or the transverse shielding performances. Finally, we show how the pristine state of the tube can be restored when applying an external field of adequate amplitude. The consequence for practical applications is that it is possible to recover shielding properties similar to those obtained in the virgin state without heating up the shield above its critical temperature TC. [less ▲]

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See detailBulk melt-processed (RE)BCO superconductors subjected to AC fields in “parallel” and “crossed” direction, experiment and modelling
Vanderbemden, Philippe ULiege; Fagnard, Jean-François ULiege; Babu, N. H. et al

Conference (2010, November)

When bulk melt-processed (RE)BCO samples are used as permanent magnets in various engineering applications (e.g. rotating machines, magnetic bearings), they may experience transient or periodic variations ... [more ▼]

When bulk melt-processed (RE)BCO samples are used as permanent magnets in various engineering applications (e.g. rotating machines, magnetic bearings), they may experience transient or periodic variations of the applied magnetic field. In such a situation, the remnant magnetization of the sample is found to decrease in running operation, which is particularly inconvenient for the long-term reliability of the system. There are several possible causes for such a phenomenon. The first is the temperature increase resulting from the losses caused by the variable applied field, and may arise when the field is parallel to the main direction of the trapped flux. The second is caused by the component of the magnetic field perpendicular to the main direction of the trapped flux (“crossed field” configuration). In the present talk we review the relevant parameters which have a detrimental impact on the remnant magnetization in both cases. Modelling results are compared to experimental data obtained on bulk YBCO samples subjected to field oscillations of large amplitude. [less ▲]

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See detailBulk organic geochemistry of sediments from Puyehue Lake and its watershed (Chile, 40°S): Implications for paleoenvironmental reconstructions
Bertrand, Sébastien; Sterken, Mieke; Vargas-Ramirez, Lourdes et al

in Palaeogeography, Palaeoclimatology, Palaeoecology (2010), 294

Since the last deglaciation, the mid-latitudes of the southern Hemisphere have undergone considerable environmental changes. In order to better understand the response of continental ecosystems to ... [more ▼]

Since the last deglaciation, the mid-latitudes of the southern Hemisphere have undergone considerable environmental changes. In order to better understand the response of continental ecosystems to paleoclimate changes in southern South America, we investigated the sedimentary record of Puyehue Lake, located in the western piedmont of the Andes in South-Central Chile (40°S). We analyzed the elemental (C, N) and stable isotopic ([delta]13C, [delta]15N) composition of the sedimentary organic matter preserved in the lake and its watershed to estimate the relative changes in the sources of sedimentary organic carbon through space and time. The geochemical signature of the aquatic and terrestrial end-members was determined on samples of lake particulate organic matter (N/C: 0.130) and Holocene paleosols (N/C: 0.069), respectively. A simple mixing equation based on the N/C ratio of these end-members was then used to estimate the fraction of terrestrial carbon ([latin small letter f with hook]T) preserved in the lake sediments. Our approach was validated using surface sediment samples, which show a strong relation between [latin small letter f with hook]T and distance to the main rivers and to the shore. We further applied this equation to an 11.22 m long sediment core to reconstruct paleoenvironmental changes in Puyehue Lake and its watershed during the last 17.9 kyr. Our data provide evidence for a first warming pulse at 17.3 cal kyr BP, which triggered a rapid increase in lake diatom productivity, lagging the start of a similar increase in sea surface temperature (SST) off Chile by 1500 years. This delay is best explained by the presence of a large glacier in the lake watershed, which delayed the response time of the terrestrial proxies and limited the concomitant expansion of the vegetation in the lake watershed (low [latin small letter f with hook]T). A second warming pulse at 12.8 cal kyr BP is inferred from an increase in lake productivity and a major expansion of the vegetation in the lake watershed, demonstrating that the Puyehue glacier had considerably retreated from the watershed. This second warming pulse is synchronous with a 2 °C increase in SST off the coast of Chile, and its timing corresponds to the beginning of the Younger Dryas Chronozone. These results contribute to the mounting evidence that the climate in the mid-latitudes of the southern Hemisphere was warming during the Younger Dryas Chronozone, in agreement with the bipolar see-saw hypothesis. [less ▲]

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See detailBulk polymerization of lactides initiated by aluminium isopropoxide, 2a). Beneficial effect of Lewis bases and transfer agents
Degée, Philippe; Dubois, Philippe ULiege; Jérôme, Robert ULiege

in Macromolecular Chemistry and Physics (1997), 198(6), 1973-1984

A high increase in the bulk polymerization rate of L,L-lactide and racemic D,L-lactide is observed when aluminium isopropoxide is added with an equimolar amount of a Lewis base, such as triphenylphosphine ... [more ▼]

A high increase in the bulk polymerization rate of L,L-lactide and racemic D,L-lactide is observed when aluminium isopropoxide is added with an equimolar amount of a Lewis base, such as triphenylphosphine (P(Φ)3) and better 4-picoline (C6H7N). Polylactide of high molecular weight and narrow molecular weight distribution is accordingly prepared in a controlled manner when the Al(OiPr)3 ; C6H7N combination is used as an initiator over a large temperature range from 110 to 180°C. A secondary alcohol, such as 2-propa-nol, has proved to be an efficient transfer agent, which allows the amount of Al per kg of polylactide to be advantageously reduced. All the alcohol molecules participate in the ring-opening polymerization even at an [iPrOH]0/[Al] ratio as high as 103. [less ▲]

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See detailBulk polymerization of lactides initiated by aluminium isopropoxide, 3a). Thermal stability and viscoelastic properties
Degée, Philippe; Dubois, Philippe ULiege; Jérôme, Robert ULiege

in Macromolecular Chemistry and Physics (1997), 198(6), 1985-1995

The thermal stability of poly(L-lactide) and L/D-lactide stereocopolymers polymerized in bulk with aluminium isopropoxide as initiator was investigated by thermogravimetric analysis, and time and ... [more ▼]

The thermal stability of poly(L-lactide) and L/D-lactide stereocopolymers polymerized in bulk with aluminium isopropoxide as initiator was investigated by thermogravimetric analysis, and time and température dependence of molecular weight and polydispersity. Compared to poly(L-lactide) prepared with stannous octoate as catalyst, the thermal stability of polylactides is remarkably enhanced when the ring-opening polymerization is initiated by aluminium alkoxide. Ultimate mechanical properties and viscoelasticity of these melt-stable thermoplastics have also been studied in relation to the polyester enan-tiomeric composition. [less ▲]

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See detailBulk polymerization of lactides initiated by aluminum isopropoxide. 1. Mechanism and kinetics
Degée, Philippe; Dubois, Philippe ULiege; Jérôme, Robert ULiege

in Macromolecular Symposia (1997), 123

Commercially available Al isopiopoxide (Al(OiPr)3) has proved to be an efficient initiator for the bulk polymerization of lactide. The ring-opening polymerization proceeds through a "coordination ... [more ▼]

Commercially available Al isopiopoxide (Al(OiPr)3) has proved to be an efficient initiator for the bulk polymerization of lactide. The ring-opening polymerization proceeds through a "coordination-insertion" mechanism and the selective rupture of the acyl-oxygen bond of the monomer Polyester chains are selectively end-capped with an aluminum alkoxide and an isopropoxy group. Therefore, substitution of Al tris(4-penten-1-olate) for Al(OiPr)3 leads to the formation of macromonomers In the temperature range from 110 to 150°C, polymerization is "living", i.e. the molecular weight can be predicted by the initial monomer-to-Al molar ratio and the monomer conversion. The narrower polydispetsity of poly(L,L-lactide) compared to the amorphous poly(D,L-lactide) ( 1.3 compared to 1.9, respectively), both prepared in the bulk, is thought to result from the restricted mobility of the crystallized isotactic polyester chains. When the temperature is increased up to 180°C, inter- and intramolecular transesterification reactions interfere with chain propagation. [less ▲]

Detailed reference viewed: 152 (8 ULiège)
See detailBulles célestes
Nazé, Yaël ULiege

Article for general public (2005)

Detailed reference viewed: 7 (0 ULiège)
See detailBulles célestes
Nazé, Yaël ULiege

Article for general public (2002)

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See detailBulles de savon dans un champ électrique uniforme
Mawet, Sébastien ULiege; Hardouin, Jérôme; Caps, Hervé ULiege

Conference (2016, January 28)

L'étude des déformations subies par une bulle lors de sa charge a commencé avec Taylor et Wilson et l'observation des cônes de Taylor. Au-delà de ces structures particulières, les déformations en elles ... [more ▼]

L'étude des déformations subies par une bulle lors de sa charge a commencé avec Taylor et Wilson et l'observation des cônes de Taylor. Au-delà de ces structures particulières, les déformations en elles-mêmes n'ont été que peu analysées. L'objectif premier de ce travail est de caractériser les changements de la surface de la bulle lorsque celle-ci est placée dans un condensateur plan et soumise à un champ électrique uniforme. Cette étude nous a permis notamment de mettre en évidence l'apparition d'un cycle d'hystérèse dans l'amplitude des déformations. [less ▲]

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See detailBulletin agrométéorologique
Tychon, Bernard ULiege; Ozer, Pierre ULiege; Eerens, H. et al

in Bulletin Agrométéorologique (2002)

Le mois de mai a été caractérisé par des conditions climatiques normales tant pour les précipitations que pour les températures. En revanche, le rayonnement a été largement déficitaire. La situation des ... [more ▼]

Le mois de mai a été caractérisé par des conditions climatiques normales tant pour les précipitations que pour les températures. En revanche, le rayonnement a été largement déficitaire. La situation des cultures est globalement favorable, avec des rendements qui s’annoncent supérieurs à ceux de 2001 à la possible exception du colza et du maïs fourrager. [less ▲]

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See detailBulletin agrométéorologique - Août 2002
Tychon, Bernard ULiege; Ozer, Pierre ULiege; Eerens, H. et al

in Bulletin Agrométéorologique (2002)

Le mois d’août a été caractérisé par des précipitations fortement excédentaires. Les températures et l’humidité furent anormalement élevées, alors que la vitesse moyenne du vent fut exceptionnellement ... [more ▼]

Le mois d’août a été caractérisé par des précipitations fortement excédentaires. Les températures et l’humidité furent anormalement élevées, alors que la vitesse moyenne du vent fut exceptionnellement faible et le rayonnement médiocre sur l’ensemble du pays. Les données de terrain disponibles confirment la tendance des prévisions de rendement du bulletin précédent (juillet 2002). La situation des cultures est globalement favorable, avec des rendements qui s’annoncent supérieurs voire similaires à ceux de 2001 à l’exception du colza. [less ▲]

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See detailBulletin agrométéorologique - Août 2003
Tychon, Bernard ULiege; De Longueville, Florence ULiege; Ozer, Pierre ULiege et al

in Bulletin Agrométéorologique (2003)

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See detailBulletin agrométéorologique - Août 2004
Tychon, Bernard ULiege; Ozer, Pierre ULiege; Horion, S. et al

in Bulletin Agrométéorologique (2004), 3(5), 1-4

Le mois d’août a été caractérisé par des précipitations, des vitesses de vent et une humidité anormalement élevées. Les valeurs de rayonnement étaient par contre anormalement faibles. Les rendements ... [more ▼]

Le mois d’août a été caractérisé par des précipitations, des vitesses de vent et une humidité anormalement élevées. Les valeurs de rayonnement étaient par contre anormalement faibles. Les rendements prévus pour le maïs fourrager sont légèrement inférieurs à ceux observés au cours des cinq années antérieures. Par contre, concernant la betterave sucrière et la pomme de terre mi-hâtive, la tendance est inverse avec des estimations globalement supérieures à la moyenne des cinq dernières années. [less ▲]

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See detailBulletin agrométéorologique - Août 2005
Tychon, Bernard ULiege; Ozer, Pierre ULiege; De Longueville, Florence ULiege et al

in Bulletin Agrométorologique (2005), 4(5), 1-4

Le mois d’août a été caractérisé par des valeurs climatiques proches de la normale. Cependant, les températures et les valeurs de rayonnement étaient anormalement faibles. Par rapport à l’année dernière ... [more ▼]

Le mois d’août a été caractérisé par des valeurs climatiques proches de la normale. Cependant, les températures et les valeurs de rayonnement étaient anormalement faibles. Par rapport à l’année dernière et, sur l’ensemble du territoire, les prévisions de rendements des principales cultures printanières sont équivalentes dans le cas de la betterave sucrière, et à la baisse pour le maïs fourrager et la pomme de terre Bintje. [less ▲]

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See detailBulletin agrométéorologique - Août 2006
Tychon, Bernard ULiege; Ozer, Pierre ULiege; De Longueville, Florence ULiege et al

in Bulletin Agrométéorologique (2006), 5(5),

L’année 2006 restera dans les annales comme étant une année exceptionnelle au niveau météorologique tant par son printemps froid que par son mois de juillet très sec et son mois d’août particulièrement ... [more ▼]

L’année 2006 restera dans les annales comme étant une année exceptionnelle au niveau météorologique tant par son printemps froid que par son mois de juillet très sec et son mois d’août particulièrement pluvieux. Ces conditions exceptionnelles rendent très délicates les prévisions de rendement. Il faut signaler que les rendements estimés sont ceux sur pieds et ils ne prennent pas en considération les pertes dues aux mauvaises conditions de récolte. Les rendements prévus pour les principales cultures de printemps restent très proches des moyennes calculées sur les 5 dernières années. [less ▲]

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See detailBulletin agrométéorologique - Avril 2002
Tychon, Bernard ULiege; Ozer, Pierre ULiege; Eerens, H. et al

in Bulletin Agrométéorologique (2002)

Detailed reference viewed: 14 (1 ULiège)