Publications ORBi OA
Bookmark and Share    
Full Text
Peer Reviewed
See detailEquivariant quantization of orbifolds
Poncin, Norbert; Radoux, Fabian ULiege; Wolak, Robert

in Journal of Geometry & Physics (2010), 60(9), 1103-1111

Equivariant quantization is a new theory that highlights the role of symmetries in the relationship between classical and quantum dynamical systems. These symmetries are also one of the reasons for the ... [more ▼]

Equivariant quantization is a new theory that highlights the role of symmetries in the relationship between classical and quantum dynamical systems. These symmetries are also one of the reasons for the recent interest in quantization of singular spaces, orbifolds, stratified spaces, etc. In this work, we prove the existence of an equivariant quantization for orbifolds. Our construction combines an appropriate desingularization of any Riemannian orbifold by a foliated smooth manifold, with the foliated equivariant quantization that we built in Poncin et al. (2009) [19]. Further, we suggest definitions of the common geometric objects on orbifolds, which capture the nature of these spaces and guarantee, together with the properties of the mentioned foliated resolution, the needed correspondences between singular objects of the orbifold and the respective foliated objects of its desingularization. [less ▲]

Detailed reference viewed: 65 (23 ULiège)
Full Text
See detailThe distributions of the OH (Δv=1) and (Δv=2) emissions on the Venus nightside
Soret, Lauriane ULiege; Gérard, Jean-Claude ULiege; Piccioni, Giuseppe et al

Conference (2010, September)

The presence of OH was detected in the spectrum of the Venus mesosphere observed at the limb with the VIRTIS instrument on board the Venus Express spacecraft [3]. The (1-0) and (2-1) transitions at 2.80 ... [more ▼]

The presence of OH was detected in the spectrum of the Venus mesosphere observed at the limb with the VIRTIS instrument on board the Venus Express spacecraft [3]. The (1-0) and (2-1) transitions at 2.80 and 2.94 mm, respectively and the (2-0) band at 1.43 mm were clearly identified. The results of this study show that a correlation is observed between the emissions associated to the Δv=1 and the Δv=2 sequences. [less ▲]

Detailed reference viewed: 284 (0 ULiège)
Full Text
See detailThe Venus oxygen nightglow and density distributions
Soret, Lauriane ULiege; Gérard, Jean-Claude ULiege; Montmessin, Franck et al

Conference (2010, September)

Observing Venus nightglow is a key tool to understand the composition and the dynamics of its atmosphere. Results deduced from observations can be implemented to produce a data model of Venus atmosphere ... [more ▼]

Observing Venus nightglow is a key tool to understand the composition and the dynamics of its atmosphere. Results deduced from observations can be implemented to produce a data model of Venus atmosphere. For instance, the Visible and Infra-Red Thermal Imaging Spectrometer (VIRTIS) instrument on board the Venus Express spacecraft is very useful to analyze the O2(a1Δ) nightglow at 1.27 µm in the Venus mesosphere. Nadir observations can be used to create a statistical map of the emission on Venus nightside. It appears that the maximum of the emission is located near the antisolar point. Limb observations also provide information on the altitude and on the shape of the emission layer. Combining nadir observations and vertically integrated limb observations improves the statistics of the emission map on Venus nightside. An associated limb profile can also be deduced for any point of the nightside. Given all these O2(a1Δ) intensity profiles, O2* density profiles can be calculated. O density profiles can also be calculated as long as CO2 density profiles are available. These can be retrieved either from the VTS3 model or from SPICAV stellar occultation measurements. Finally, three-dimensional maps of excited molecular and atomic oxygen densities can be generated. The oxygen density map shows significant differences from the VTS3 model predictions. [less ▲]

Detailed reference viewed: 16 (0 ULiège)
Full Text
Peer Reviewed
See detailMALDI mass spectrometry imaging of proteins exceeding 30,000 daltons.
Franck, Julien; Longuespée, Rémi ULiege; Wisztorski, Maxence et al

in Medical Science Monitor : International Medical Journal of Experimental and Clinical Research (2010), 16(9), 293-9

Detailed reference viewed: 68 (1 ULiège)
Full Text
Peer Reviewed
See detailTOLERANCE INTERVALS AS CONTROL CHART: COMPARISON TO CLASSIC SHEWHART X̅-R CONTROL CHART
Marini Djang'Eing'A, Roland ULiege; Lambert, Véronique; Denooz, Raphael ULiege et al

Poster (2010, September)

Detailed reference viewed: 253 (43 ULiège)
Full Text
Peer Reviewed
See detailApplication of experimental design for the HPLC-UV-MS separation of aporphine alkaloids from leaves of Spirospermum Penduliflorum thouars
Rafamantanana, Mamy H.; Debrus, Benjamin ULiege; Raoelison, Guy E. et al

Poster (2010, September)

Detailed reference viewed: 110 (14 ULiège)
Full Text
Peer Reviewed
See detailTransfer of a conventional LC method for the screening of conterfeit antimalarial medicines to UHPLC
Nistor, Iolanda ULiege; Lecomte, Frédéric ULiege; Mbinze Kindenge, Jérémie et al

Poster (2010, September)

Detailed reference viewed: 127 (56 ULiège)
Full Text
See detailEvaluation des caractéristiques acoustiques d’une rue à partir de mesures
Billon, Alexis ULiege; Picaut, Judicaël

in Acoustique & Techniques (2010), 62

The knowledge of acoustic properties of urban surface (absorption, reflection and diffusion coefficients) is very important in the framework of the noise mapping in urban areas. Indeed, most of noise ... [more ▼]

The knowledge of acoustic properties of urban surface (absorption, reflection and diffusion coefficients) is very important in the framework of the noise mapping in urban areas. Indeed, most of noise prediction tools require the use of such coefficients in the boundary equations of the sound propagation models. An indirect method combining experimental data and numerical simulations is then proposed in order to obtain the absorption and scattering coefficients of an urban street. An empirical relationship is first established, linking the scattering variation to an absorption variation. This relation transforms a problem with two variables (absorption and scattering) into a single variable problem (absorption) for a reference scattering coefficient. Secondly, the absorption coefficient is adjusted in order that the numerical results match the experimental data in terms of sound pressure level distribution. Lastly, the obtained value of absorption, associated with the empirical relation, allows to test different absorption and diffusion pairs presenting the same sound level distribution against the experimental reverberation times. Following this procedure, a coefficients pair minimising the discrepancies both on the sound level distribution and the reverberation time is obtained. This method is here applied to a Haussmaniann street. Results show that the obtained absorption coefficients are weak whereas the scattering is quite high, which is physically consistent as the façades are composed of weakly absorbent materials (stone and glass) and fitted with a lot of recesses and protuberances creating scattering. [less ▲]

Detailed reference viewed: 104 (6 ULiège)
Full Text
See detailThermo-elastic distortion measurements by holographic interferometry and correlation with finite element models for SiC connections/junctions on spacecraft
Thizy, Cédric ULiege; Stockman, Yvan ULiege; Eliot, Fabienne et al

Conference (2010, September)

Scientific, earth observation and telecommunication spacecrafts are submitted to severe thermal environments while their mission performance requires more and more high stable structures. Due to on-ground ... [more ▼]

Scientific, earth observation and telecommunication spacecrafts are submitted to severe thermal environments while their mission performance requires more and more high stable structures. Due to on-ground constraints, the verification by test of the performances of these stable structures is usually limited. However accurate prediction methodology and verification capability of thermal distortions becomes mandatory for ensuring the in-orbit performance objectives of future programs. The main thermo-elastic contributors of the final stability performances are: - Material and assembly physical properties knowledge (Coefficient of Thermal Expansion, Young modulus, Poisson ratio…) - Modeling and simulation capabilities: temperature mapping, accurate thermo-elastic finite element models… - Verification test performances: advanced measurement techniques are required to characterize and determine the different main contributors to the final end to end performance and to perform accurate correlation. In this study, material characteristics are assumed to be well known. The objective was to improve and develop analytical predictions and verification of thermo elastic distortions using sample testing for modeling correlation. The samples have been chosen to be representative of the connections/junctions that can be encountered in stable structures on spacecraft and can have a dominant impact on the instrument stability. The results presented in this paper concern SiC/SiC and SiC/TA6V bonded and bolted samples. For the tests, temperature variations between -20°C and +15°C from ambient have been applied to the samples. Thermo-elastic distortions have been measured with a holographic camera. This holographic camera can measure displacements in the range of 20 nm to 20 m without physical contact with the samples. The tests results have been compared to the predictions obtained by Finite Element Modelling. From this comparison modelling guidelines have been issued with the aim of improving the accuracy of computed thermo elastic distortions: the FEM predictions lead to quite good correlation with the test data, with most of the time less than 10% discrepancies. A second phase to this study is planned. The objective is to implement all the benefits on improvement of thermo-elastic distortions predictions and verification achieved during the first phase on real spacecraft hardware. [less ▲]

Detailed reference viewed: 131 (3 ULiège)
Full Text
Peer Reviewed
See detailApplication of Eurocode 3 to steel connections with four bolts per horizontal row
Demonceau, Jean-François ULiege; Weynand, Klaus; Jaspart, Jean-Pierre ULiege et al

in Batista, E.; Vellasco, P.; de Lima, L. (Eds.) Proceedings of the SDSS'Rio 2010 conference (2010, September)

Eurocode 3 Part 1-8 provides detailed application rules for the design of bolted end-plate connections. Although these rules apply to connections with any number of bolt rows, they are limited to ... [more ▼]

Eurocode 3 Part 1-8 provides detailed application rules for the design of bolted end-plate connections. Although these rules apply to connections with any number of bolt rows, they are limited to configurations with two bolts in each row. However, it is sometimes more economical to place four bolts in one row. This configuration is commonly met in different countries in Europe and, in particular, in Germany. The theoretical model on which the Eurocode 3 application rules are founded is general and can be potentially applied to connections with four bolts per row. However, specific design rules need to be developed. In the present paper, easy-to-apply analytical design rules aimed at predicting the mechanical properties of connections with four bolts per row and in full agreement with the Eurocode 3 approach are detailed. Validations through comparisons to experimental test results recently performed in the framework of a German national project are also presented. [less ▲]

Detailed reference viewed: 580 (20 ULiège)
Full Text
See detailÉtude des apports alimentaires et des possibilités de complémentation minérale de bovins N’Dama sur pâturages artificiels à Brachiaria sp. au ranch de Kolo (RDC)
Goubau, Amaury ULiege

Master's dissertation (2010)

Les apports et les besoins alimentaires des bovins N’Dama, pâturant sur des pâturages artificiels à Brachiaria sp., au ranch de Kolo, en République démocratique du Congo, ont été déterminé afin de mettre ... [more ▼]

Les apports et les besoins alimentaires des bovins N’Dama, pâturant sur des pâturages artificiels à Brachiaria sp., au ranch de Kolo, en République démocratique du Congo, ont été déterminé afin de mettre en évidence un éventuel déficit en énergie, protéines et minéraux. La qualité et la quantité des régimes consommés par deux catégories animales (bouvillons et vaches de réforme) a été estimée par spectroscopie dans le proche infrarouge (SPIR) au cours de deux période (petite saison sèche et petite saison des pluies) sur deux types de pâturages semés de Brachiaria decumbens et Brachiaria ruziziensis. Les apports énergétiques et protéiques fournis par les deux couverts satisfont les besoins des animaux au cours des deux périodes. Pour les bouvillons, l’apport prélevé sur les deux types de pâturages, 4,85 unités fourragères (UF) en première période, permettent, par rapport aux besoins théoriques d’un bouvillon en croissance de 260 kg, un GQM de 600 g/j. En seconde période, les apports sont plus importants sur la parcelle à B. decumbens (5,6 UF) et permettent un GQM théorique de 700 g/j, tandis qu’ils diminuent sur la parcelle à B. ruziziensis (4,4 UF), ne permettant plus qu’un GQM théorique de 400 g/j. C’est en seconde période que les performances de croissances théoriques au pâturage sont les plus élevés pour les vaches de réforme en finition, avec 500 g/j sur la parcelle à B. decumbens et 300 g/j sur la parcelle à B. ruziziensis. Les besoins en minéraux sont partiellement couverts. Les apports en P, Ca, Mg, K, Mn et Fe sont suffisants. Par contre ceux en Na, Cu et Zn ne le sont pas. Une complémentation minérale en ces éléments doit donc être apportée au cours des deux périodes sur les deux types de pâturages. L’apport doit être sous forme de bloc afin de contrôler l’ingestion et limiter les vols. [less ▲]

Detailed reference viewed: 159 (21 ULiège)
Full Text
See detailLa protection de la propriété intellectuelle au coeur de la competition mondiale: l'accord commercial anti-contrefaçon.
Vlassis, Antonios ULiege

in Ina GLOBAL (2010), la Revue des industries créatives et des médias (online)

- L’enjeu de la protection des droits de propriété intellectuelle au cœur de la compétition mondiale - ACTA: La nature et les objectifs du traité - Les négociations sur l'ACTA: Confidentialité et ... [more ▼]

- L’enjeu de la protection des droits de propriété intellectuelle au cœur de la compétition mondiale - ACTA: La nature et les objectifs du traité - Les négociations sur l'ACTA: Confidentialité et discrétion - Des inquiétudes et des réticences sur le caractère et le contenu de l'accord - Un stand-alone agreement au-dessus des accords existants ? - Une efficacité discutée [less ▲]

Detailed reference viewed: 36 (2 ULiège)
Full Text
Peer Reviewed
See detailGrazing with a mobile milking robot
Dufrasne, Isabelle ULiege; Robaye, Vincent ULiege; Istasse, Louis ULiege et al

in Schnyder, Hans; Isselstein, J.; Taube, F. (Eds.) et al Grassland in a changing world (2010, September)

The size of dairy cow herds in Europe is increasing. Farmers have to manage larger herds but want, at the same time, benefit from a normal social life. So, the milking robot can bring solutions. Its use ... [more ▼]

The size of dairy cow herds in Europe is increasing. Farmers have to manage larger herds but want, at the same time, benefit from a normal social life. So, the milking robot can bring solutions. Its use can reduce physical labour and allow flexibility. During the past 10 years, the number of milking robots has been increased in Europe. In farm practice, this technology has resulted in a reduction in the amount of grazing even though grazing appears as a natural practice which is appreciated by the consumers. At the experimental farm of the University of Liège, we are developing the concept of a mobile milking robot in collaboration with a private company. This prototype will allow cows to graze and could be moved to different locations on pastures during the grazing season. The prototype will be used indoors during the end of the winter season and will be moved outdoor during the 2010 grazing season. The feasibility of this prototype has to be tested in the field. Milk production and quality, the number of visits and the grazing parameters will be recorded. Different equipments in view to attract the cows to the robot as the presence of a cow brush, the location of the drinking point, will be compared. The behaviour of animals will be also assessed. [less ▲]

Detailed reference viewed: 134 (7 ULiège)
Full Text
See detailSleep in Disorders of Consciousness
Schabus, Manuel; Cologan, Victor ULiege; Weihart, K et al

Poster (2010, September)

Résultats préliminaires de l'étude du sommeil chez les patients cérébrolésés en état de conscience altéré.

Detailed reference viewed: 14 (1 ULiège)
Full Text
Peer Reviewed
See detailNitrogen excretions in dairy cows on a rotational grazing system: effects of fertilization type, days in the paddock and time period.
Dufrasne, Isabelle ULiege; Robaye, Vincent ULiege; Istasse, Louis ULiege et al

in Schnyder, Hans; Isselstein, J.; Taube, F. (Eds.) et al Grassland in a changing world (2010, September)

The present study aims to quantify nitrogen (N) excretions in dairy cows on a rotational grazing system with different types of fertilization (mineral N, slurry and compost) after 3 or 5 days in the ... [more ▼]

The present study aims to quantify nitrogen (N) excretions in dairy cows on a rotational grazing system with different types of fertilization (mineral N, slurry and compost) after 3 or 5 days in the paddock and during two different periods in June and September. Individual samples of faeces and urine were collected to assess N excretions from cows in the paddocks. The urea content in milk from the tank or from the individual cows was also measured. N intake was higher on day 3 compared to day 5 (465 vs 425 g d-1, P<0.001) and in September as compared to June (488 vs 425 g d-1, P<0.001) but was not influenced by the fertilization type. The amount of excreted urinary N was significantly higher in the mineral N group than in the two other groups (272 vs 226 g d-1; P<0.001). The N excretion in faeces and urines decreased with days (92 vs 84 g d-1, P<0.01; 256 vs 228 g d-1, P<0.001 respectively for days 3 and 5). Urinary N excretion was lower in June than in September (181 vs 302 g d-1, P<0.001) while the N excretion in the faeces was higher (96 vs 80 g d-1, P<0.01). [less ▲]

Detailed reference viewed: 53 (4 ULiège)
Full Text
Peer Reviewed
See detailThe Alliance's nuclear issue within the future "strategic concept"
Dumoulin, André ULiege

in Etudes de l'IRSEM (2010), (4),

Detailed reference viewed: 13 (2 ULiège)