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See detailGrey-box identification of a non-linear solar array structure using cubic splines
Noël, Jean-Philippe ULg; Kerschen, Gaëtan ULg; Emmanuel, Foltête et al

in International Journal of Non-Linear Mechanics (2014), 67

Most identification methods in non-linear structural dynamics assume in advance a mathematical model of the non-linearities. This is however possible in specific situations only, since non-linear effects ... [more ▼]

Most identification methods in non-linear structural dynamics assume in advance a mathematical model of the non-linearities. This is however possible in specific situations only, since non-linear effects may be caused by numerous phenomena and a priori knowledge is generally limited. The present paper investigates the usefulness of piecewise third-order polynomials, termed cubic splines, to identify the complex non-linear dynamics of solar arrays in their stowed configuration. The estimation of the model parameters is achieved using the frequency-domain non-linear subspace identification (FNSI) method. A distinct advantage of the FNSI approach is its capability to calculate accurately a large number of parameters, while maintaining an acceptable computational burden. This makes tractable the use of cubic splines to represent non-linearity in real-life mechanical systems, as the dimensionality of the inverse problem is known to increase dramatically in this case. The experimental structure of interest consists of two parallel aluminium plates assembled with bolted connections. This application is challenging because of the existence of impacts between the two plates at high excitation amplitude, and of the activation of complicated stiffness and damping mechanisms within the bolted connections. [less ▲]

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See detailToward a tool aimed to quantify soil compaction risks at a regional scale: application to Wallonia (Belgium)
D'Or, Dimitri; Destain, Marie-France ULg

in Soil & Tillage Research (2014), 144

The spatial analysis of the soil compaction risk has been developed at the regional level and applied to Wallonia (Belgium). The methodology is based on the estimation of the probability of exceeding the ... [more ▼]

The spatial analysis of the soil compaction risk has been developed at the regional level and applied to Wallonia (Belgium). The methodology is based on the estimation of the probability of exceeding the preconsolidation stress due to the application of loads on the soil. Preconsolidation stresses (Pc) are computed from the pedotransfer functions of Horn and Fleige (2003) at pF 1.8 and 2.5 and classified into 6 categories ranging from very low Pc (< 30 kPa) to extremely high Pc (> 150 kPa). The computation requires the knowledge of pedological (texture, organic content), mechanical (bulk density, cohesion, internal friction angle), and hydraulic variables (water content available, non-available water content, air capacity, saturated hydraulic conductivity). These variables are obtained from databases like HYPRES or AARDEWERK or from pedotransfer functions. The computation of Pc takes into account the spatial structure of the data: in some cases, data are abundant (e.g. texture data) and spatial variability is taken into account through geostatistical methods. In other cases, the data is sparse but uncertainty information can be extracted from the knowledge of the statistical distribution. Maps of the most probable Pc class are produced. Uncertainty is computed as the classification error probability. Implementation of these methods in Wallonia showed that Pc values higher than 120 kPa are reached either on 64 % of the territory at pF 2.5 or on 55 % at pF 1.8. A higher uncertainty was found at pF 2.5 than at pF 1.8. Uncertainty was also found higher for clay and clayed loess than for other textural classes present in Wallonia. The risk of compaction is defined as the probability that Pc is exceeded by the stress created by a load applied to the soil at a depth of 40 cm, the loads being similar to those induced by agricultural or forestry tires. It appeared that subsoil compaction risks exist mainly in loamy forest soils with small coarse fragments supporting loads similar to that existing on logging machines. In the zones where the uncertainty is low, the developed tool could be used as a basis for providing policy measures in order to promote soil-friendly farming and forest practices. [less ▲]

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See detailConclusion
Famerie, Etienne ULg

in La diplomatie romaine sous la République : réflexions sur une pratique (2014)

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See detailExperimental validation of a thermal model of a LOx flooded ball bearing
Servais, Christophe ULg; Bozet, Jean-Luc ULg; Kreit, Patrick ULg et al

in Tribology International (2014), 80

Ball bearings of turbopumps of rocket engines work in very singular conditions; they are flooded into liquid oxygen or liquid hydrogen. Therefore, the use of any conventional lubricants (oil or grease) is ... [more ▼]

Ball bearings of turbopumps of rocket engines work in very singular conditions; they are flooded into liquid oxygen or liquid hydrogen. Therefore, the use of any conventional lubricants (oil or grease) is prescribed. Although cryogenic fluids can cool this kind of ball bearing, they cannot separate the surfaces in contact. As a result, there is a significant increase in frictional power losses. This paper presents tests performed on a cryotechnic ball bearing flooded in liquid oxygen. The test results showed that beyond a critical loading of the bearing, a sudden increase in temperature occurred. A thermal model is also put forward, in order to understand and anticipate especially the thermal instability described above. [less ▲]

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See detailSur les définitions de Dieu. Entretien avec Valère Novarina
Dubouclez, Olivier ULg; Novarina, Valère

in Littérature (2014)

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See detailComment finir, ou la prière faite au théâtre
Dubouclez, Olivier ULg

in Littérature (2014, December)

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See detailLes corps des scientifiques et de l’intellectuel dans la revue La recherche
Dondero, Maria Giulia ULg

in Havelange, Carl (Ed.) La lettre et l'image (2014, December)

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See detailLe relief de Neumagen et les bibliothèques antiques
Marganne, Marie-Hélène ULg

in Capasso, Mario; De Nonno, Mario (Eds.) Scritti in memoria di Paolo Radiciotti (2014)

Mise en contexte du relief de Neumagen aujourd'hui disparu représentant une bibliothèque avec des rouleaux de papyrus et recherches sur les circonstances de la publication, à Liège, en 1670, par l ... [more ▼]

Mise en contexte du relief de Neumagen aujourd'hui disparu représentant une bibliothèque avec des rouleaux de papyrus et recherches sur les circonstances de la publication, à Liège, en 1670, par l'imprimeur Jean Matthias Hovius, des Antiquitatum et Annalium Trevirensium libri XXV de Ch. Brouwer et J. Masen contenant la gravure de ce relief. [less ▲]

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See detailFamily Members of Patients with Abdominal Aortic Aneurysms are at Increased Risk for Aneurysms: Analysis of 618 Probands and their Families from the Liege AAA Family Study.
SAKALIHASAN, Natzi ULg; Defraigne, Jean-Olivier ULg; Kerstenne, Marie-Ange et al

in Annals of vascular surgery (2014), 28

BACKGROUND: The objectives were to answer the following questions using a well-characterized population in Liege, Belgium: 1) what percentage of abdominal aortic aneurysm (AAA) patients have a positive ... [more ▼]

BACKGROUND: The objectives were to answer the following questions using a well-characterized population in Liege, Belgium: 1) what percentage of abdominal aortic aneurysm (AAA) patients have a positive family history for AAA, 2) what is the prevalence of AAAs among relatives of AAA patients; and 3) do familial and sporadic AAA cases differ in clinical characteristics. METHODS AND RESULTS: Unrelated AAA patients diagnosed at the Cardiovascular Surgery Department, University Hospital of Liege, Belgium, between 1999 and 2012 were invited to the study. A detailed family history was obtained in interviews and recorded using Progeny software. In the initial interview 62 (10%) of the 618 AAA patients reported a positive family history for AAA. We divided the 618 patients into two study groups: Group I: 296 AAA patients (268; 91% males) were followed up with computerized tomography combined with positron emission tomography, and Group II: 322 AAA patients (295; 92% males) whose families were invited to ultrasonography screening. Ultrasonography screening identified 24 new AAAs among 186 relatives (>/= 50 years) of 144 families yielding a prevalence of 13%. The highest prevalence (25%) was found among brothers. By combining the number of AAAs found by ultrasonography screening with those diagnosed previously the observed lifetime prevalence of AAA was estimated to be 32% in brothers. The familial AAA cases were more likely to have a ruptured AAA than the sporadic cases (8% vs. 2.4%; P<0.0001). CONCLUSIONS: The findings confirm previously found high prevalence of AAA among brothers, support genetic contribution to AAA pathogenesis and provide rationale for targeted screening of relatives of AAA patients. [less ▲]

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See detailMigration, race and citizenship: the postcolonial malus of the Belgo-Congolese in Belgium
Demart, Sarah ULg

Scientific conference (2014, November 27)

In this paper I look at the particular situation of Congolese and Belgian-Congolese citizens in Belgium, the former colonial metropole. From research conducted over ten years within Congolese circles I ... [more ▼]

In this paper I look at the particular situation of Congolese and Belgian-Congolese citizens in Belgium, the former colonial metropole. From research conducted over ten years within Congolese circles I argue that postcolonial immigrants/citizens have for the last three decades been experiencing a significant social malus. Not only does daily racial discrimination inform and supply it but so also does treatment by the state itself through its various institutions. Looking at some data collected from political, associative and artistic spheres I argue that the Congolese in Belgium have to deal with a postcolonial malus. My research is grounded on a comprehensive anthropology which privileges the actors’ own perspective. I thereby explore the elements, trends or configurations of the post-migratory situation which may be considered inherited from colonialism. Finally, I discuss the reason why despite three decades of “postcolonial activism”, the postcolonial critique is not a live social issue in French-speaking Belgium. [less ▲]

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See detailFoucault et Deleuze et Sami-Ali : postmodernité et psychothérapie.
Englebert, Jérôme ULg

Conference (2014, November 22)

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See detailVers un transport aérien plus écologique et plus économique
Lurkin, Virginie ULg

Conference given outside the academic context (2014)

de l’avion en vol. Mieux, on peut montrer que la position du centre de gravité (qui dépend du chargement de l’avion) affecte la consommation de carburant. Ce résultat revêt une importance majeure dans un ... [more ▼]

de l’avion en vol. Mieux, on peut montrer que la position du centre de gravité (qui dépend du chargement de l’avion) affecte la consommation de carburant. Ce résultat revêt une importance majeure dans un contexte d’augmentation des prix du pétrole et où il s’agit de réduire les émissions polluantes. Pour un transport aérien plus économique, il s’agit aussi, en cas de livraisons à différents endroits, de réduire au maximum les temps de chargements et de déchargements afin de limiter les coûts liés aux paiements des salariés et à l’utilisation de chaque aéroport intermédiaire. Au cours de mon exposé, je présente un modèle mathématique qui vise à trouver le chargement qui minimise la consommation de carburant et les temps de chargements et déchargements. Je partage avec nous les résultats de mes recherches dont les applications garantissent un impact écologique et économique positif. [less ▲]

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See detailLa pensée et l'institution psychanalytiques à l'épreuve e la question de l'homosexualité
Naziri, Despina ULg

Scientific conference (2014, November 20)

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See detailIs there a global procedural learning deficit in children with Specific Language Impairment ?
Desmottes, Lise ULg; Maillart, Christelle ULg; Lejoly, Kelly ULg et al

Poster (2014, November 13)

The study of procedural learning abilities in children with Specific Language Impairment (Procedural Deficit Hypothesis, PDH; Ullman & Pierpont, 2005) remains a relatively unexplored field of research ... [more ▼]

The study of procedural learning abilities in children with Specific Language Impairment (Procedural Deficit Hypothesis, PDH; Ullman & Pierpont, 2005) remains a relatively unexplored field of research. Since most evidence comes from studies using tasks which involve learning of sequenced patterns, research using other procedural learning paradigms (like motor adaptation tasks) is needed to further evaluate the PDH in children with Specific Language Impairment (SLI). Therefore, in this study, we examined the ability of children with and without SLI to learn, consolidate and generalize a mirror-tracing task, a paradigm that does not involve sequence learning and had never been used in SLI. Children with SLI and typical developing (TD) matched children participated in the study. Children with SLI were included if they scored below -1.25 SD of the expected normative performance in at least 2 language areas. Both groups had to trace ten 5-pointed stars seen only in mirror-reversed view in two learning sessions separated by a one-week delay. The transfer phase consisted in tracing a new figure. The time required to complete the tracing, and the number of errors committed were recorded. Full results will be presented and discussed during the presentation of the paper. [less ▲]

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See detailDISTRIBUTION OF CAPSULAR POLYSACCHARIDES OF STREPTOCOCCUS AGALACTIAE STRAINS FROM URUGUAY. MULTIPLEX PCR VERSUS CONVENTIONAL CAPSULAR SEROTYPING
Rodriguez Cuns, Grisel ULg; BOREUX, Raphaël ULg; ADAMS, Pauline et al

in XIX Lancefield International Symposium on Streptococci and Streptococcal Diseases, Program and Abstract book (2014, November 11)

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See detailThe Airline Container Loading Problem with Pickup and Delivery
Lurkin, Virginie ULg; Schyns, Michael ULg

Conference (2014, November 09)

We address the problem of allocating containers into predefined positions of a carrier, in this case aircraft, under several realistic structural and safety constraints. The originality of our approach is ... [more ▼]

We address the problem of allocating containers into predefined positions of a carrier, in this case aircraft, under several realistic structural and safety constraints. The originality of our approach is to allow multi-trips with pickup and delivery at some intermediate locations. The objective is to minimize the economic and environmental costs including the impact of the intermediate operations. We resort to an integer linear model. Numerical experiments have been performed using a standard B\&C library. Heuristics are developed to speed up the process. [less ▲]

Detailed reference viewed: 7 (3 ULg)