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See detailPENSANDO LA CIUDAD SOSTENIBLE MÁS ALLÁ DE LA DICOTOMÍA ECOLOGÍA URBANA Y MEDIOAMBIENTE URBANO: EL CASO DE LA GOBERNANZA DEL AGUA EN COCHABAMBA
Cabrera Quispe, Juan Edson ULg; Farah, Jihad ULg

Conference (2014, November 24)

In this article, we go back on two ways of taking into account the environmental dimension in urban planning and governance. We stress the difficult articulation between these two approaches – “urban ... [more ▼]

In this article, we go back on two ways of taking into account the environmental dimension in urban planning and governance. We stress the difficult articulation between these two approaches – “urban ecology” and “urban environment” – and the actual impasse the discipline of urban planning finds itself in in its quest of the sustainable city. These two approaches for acting on the city by considering the complexity of its milieu build on different representations of this milieu and different modes of action legitimation. Negating each other, they can difficultly coexist, even less articulate. Through the example of water management in Cochabamba, we stress the tensions between these approaches. We point also to the awkward and marginalized position of urban planning and challenges it must face to regain a capacity of action in contemporary fragmented cities that know complex governance landscapes and rare or endangered resources. [less ▲]

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See detailImpact of steam explosion treatment on chemical configuration of Tall Fescue lignin : structural elucidation using NMR spectroscopy
Maniet, Guillaume ULg; Jacquet, Nicolas ULg; Gillet, Sébastien ULg et al

Poster (2014, November 24)

In the economic and energy context of our society, it is universally recognized that alternatives to petrochemicals products must be found. To overcome this problem, renewable lignocellulosic biomass ... [more ▼]

In the economic and energy context of our society, it is universally recognized that alternatives to petrochemicals products must be found. To overcome this problem, renewable lignocellulosic biomass could be used to produce high value products. To achieve this objective, pretreatment processes are required to allow the breakdown of lignocellulosic structure and increase accessibility of the material. In this way, steam explosion is a thermo-mechano-chemical pretreatment which allows the opening of lignocellulosic material structural components and includes modifications of the physical properties of the material, hydrolysis of hemicellulosic components and modification of the chemical structure of lignin [1]. This study is focused on the impact of various steam explosion treatments on the chemical configuration of tall fescue lignin. NMR analyses perform on the Festuca L. pretreated samples show variations of links with treatment intensity. Observations show double phenomen :re-polymerization and depolymerization of the lignin structure during steam explosion process [2]. In parallel, HPSEC analyses show modifications in the molecular weight of the lignin obtained after the steam explosion treatment. [less ▲]

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See detailA capillary Archimedes’ screw
Darbois-Texier, Baptiste ULg; Dorbolo, Stéphane ULg

Conference (2014, November 23)

As used by Egyptians for irrigation and reported by Archimedes, a screw turning inside a hollow pipe can pull out a fluid againt gravity. At a centimetric scale, an analagous system can be found with a ... [more ▼]

As used by Egyptians for irrigation and reported by Archimedes, a screw turning inside a hollow pipe can pull out a fluid againt gravity. At a centimetric scale, an analagous system can be found with a drop pending on a rotating spiral which is tilted toward the horizontal. The ascent of the drop to the top of the spiral is considered and a theoretical model based on geometrical considerations is proposed. The climb of the drop is limited by the fluid deposition on the screw at high capillary number and by a centrifugation phenomenon. We find out the range of fluid proprities and spiral characteristics for which an ascending motion of the drop is possible. Finally we discuss the efficiency of such system to extract a fluid from a bath at a centrimetric scale. [less ▲]

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See detailL'ECMO, Témoignage de deux infirmiers
KOCH, Jean-Noël ULg; BODSON, Sébastien ULg

Conference (2014, November 22)

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See detailLong-term evolution and seasonal modulation of methanol above Jungfraujoch (46.5°N, 8.0°E): Optimisation of the retrieval strategy, comparison with model and independant observations
Bader, Whitney ULg; Stavrakou, T; Muller, J-F et al

in Atmospheric Measurement Techniques (2014), 7

Methanol (CH3OH) is the second most abundant organic compound in the Earth's atmosphere after methane. In this work, we present the first long-term time series of methanol total, lower tropospheric and ... [more ▼]

Methanol (CH3OH) is the second most abundant organic compound in the Earth's atmosphere after methane. In this work, we present the first long-term time series of methanol total, lower tropospheric and upper tropospheric-lower stratospheric partial columns derived from the analysis of high resolution Fourier transform infrared solar spectra recorded at the Jungfraujoch station (46.5° N, 3580 m a.s.l.). The retrieval of methanol is very challenging due to strong absorptions of ozone in the region of the selected υ8 band of CH3OH. Two wide spectral intervals have been defined and adjusted in order to maximize the information content. Methanol does not exhibit a significant trend over the 1995–2012 time period, but a strong seasonal modulation characterized by maximum values and variability in June–July, minimum columns in winter and a peak-to-peak amplitude of 130%. In situ measurements performed at the Jungfraujoch and ACE-FTS occultations give similar results for the methanol seasonal variation. The total and lower tropospheric columns are also compared with IMAGESv2 model simulations. There is no systematic bias between the observations and IMAGESv2 but the model underestimates the peak-to-peak amplitude of the seasonal modulations. [less ▲]

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See detailImpact environnemental des stations de méthanisation agricoles
Adam, Gilles ULg

Conference given outside the academic context (2014)

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See detailENMG non classique
WANG, François-Charles ULg

Scientific conference (2014, November 20)

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See detailOn the Use of Principal Component Analysis for Parameter Identification and Damage Detection in Structures
Golinval, Jean-Claude ULg

Conference (2014, November 20)

Modal analysis is used extensively for understanding the dynamic behaviour of structures as well as for structural health monitoring or damage detection based on output-only measurements. In this ... [more ▼]

Modal analysis is used extensively for understanding the dynamic behaviour of structures as well as for structural health monitoring or damage detection based on output-only measurements. In this presentation, a different approach based on principal component analysis is considered. Principal component analysis (PCA), also called proper orthogonal decomposition (POD), is a multi-variate statistical method that aims at obtaining a compact representation of the data. In the present paper, PCA (POD) is used for three purposes, namely damage detection, structural health monitoring and identification of nonlinear parameters. The key idea of PCA is to reduce a large number of measured data to a much smaller number of uncorrelated variables while retaining as much as possible of the variation in the original data. To this purpose, an orthogonal transformation to the basis of the eigenvectors of the sample covariance matrix is performed, and the data are projected onto the subspace spanned by the eigenvectors corresponding to the largest eigenvalues. This transformation has the property to decorrelate the signal components and to maximize variance. The first problem to which PCA is applied here is the damage detection problem. When applied to vibration measurements, it can be shown that the basis of eigenvectors (called the proper orthogonal modes) span the same subspace as the mode-shape vectors of the monitored structure. Thus the damage detection problem may be solved using the concept of subspace angle between a reference subspace spanned by the eigenvectors of the initial (undamaged) structure and the subspace spanned by the eigenvectors of the current (possibly damaged) structure. The second problem concerns structural health monitoring of civil engineering structures when environmental effects (e.g. the influence of the variation of the ambient temperature) have to be removed from the structural changes. In this case, PCA may be applied on identified modal features (e.g. the natural frequencies) to separate the changes due to environmental variations from the changes due to damage sources. This procedure is illustrated on the example of a real bridge located in Luxembourg. The third problem is related to the estimation of nonlinear parameters using model updating techniques. In this case, the most interesting property of PCA is that it minimizes the average squared distance between the original signal and its reduced linear representation. When applied to nonlinear problems, PCA gives the optimal approximating linear manifold in the configuration space represented by the data. The linear nature of the method is appealing because the theory of linear operators is still available. However, it should be borne in mind that it also exhibits its major limitation when the data lie on a nonlinear manifold. [less ▲]

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See detailPremières mises en liberté avant jugement devant la Cour pénale internationale
Deprez, Christophe ULg

E-print/Working paper (2014)

Ce billet évoque les premières libérations avant jugement intervenues devant la Cour pénale internationale (octobre 2014). Après avoir été soumis à un comité de lecture, il a été publié sur le 'blogue' de ... [more ▼]

Ce billet évoque les premières libérations avant jugement intervenues devant la Cour pénale internationale (octobre 2014). Après avoir été soumis à un comité de lecture, il a été publié sur le 'blogue' de la Clinique de droit international pénal et humanitaire de l'Université de Laval. [less ▲]

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See detailThe physical education teacher as a physical activity promoter: Current developments
Cloes, Marc ULg

Conference (2014, November 19)

The physical education teacher is considered as a cornerstone of the physical activity promotion in the schools. This presentation proposes answers to three questions: (1) Why to promote physical activity ... [more ▼]

The physical education teacher is considered as a cornerstone of the physical activity promotion in the schools. This presentation proposes answers to three questions: (1) Why to promote physical activity at school? (2) Why the PE teacher should play a central role? (3) How the PE teacher could play such role? In conclusion, it is important to remember that (1) PE teachers should become the cornerstones of the PA promotion at school; (2) They have to be involved in PE as well as in the other dimension of PA at school; (3) They have to collaborate (they are not alone), and; (4) Pre service and inservice PETE has to be adapted to show the way and change the mentalities [less ▲]

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See detailDesign and implementation of a T impedance matching network for the radiocommunication subsystem aboard the OUFTI-1 nanosatellite
Boutaayamou, Mohamed ULg; Crosset, Nicolas ULg; Werner, Xavier ULg et al

in Proceedings of the URSI Forum 2014 (2014, November 18)

We describe how we handled an unexpected impedance matching issue on the receiver side (at UHF) of the radiocommunication system aboard the OUFTI-1 nanosatellite of the University of Liège. Our approach ... [more ▼]

We describe how we handled an unexpected impedance matching issue on the receiver side (at UHF) of the radiocommunication system aboard the OUFTI-1 nanosatellite of the University of Liège. Our approach relied on a combination of novel analytical developments combined with experimentation. [less ▲]

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See detailAdditive Manufacturing of Metallic Materials: Case Studies in the Processing of Stainless Steel 316L and of Alloy Ti-6Al-4V by Laser Beam Melting
Mertens, Anne ULg

Learning material (2014)

This powerpoint presentation was used as teaching material in a seminar given as part of the course “Compléments de fabrication mécanique et FAO” at Université catholique de Louvain. It outlines important ... [more ▼]

This powerpoint presentation was used as teaching material in a seminar given as part of the course “Compléments de fabrication mécanique et FAO” at Université catholique de Louvain. It outlines important current issues in the developments of additive technologies for the processing of metallic materials by discussing two case studies from researches carried out by the Metallic Materials Science Unit (ULg). In particular, two different metallic alloys, i.e. stainless steel 316L and Ti-6Al-4V, have been processed by laser beam melting under similar conditions, and their microstructures and mechanical behaviours have been compared in details. Under the investigated conditions, Ti-6Al-4V exhibits a more complex behaviour than stainless steel 316L with respect to the occurrence of microstructural and mechanical anisotropy. Moreover, Ti-6Al-4V appears more sensitive to the build-up of internal stresses when compared with stainless steel 316L, whereas stainless steel 316L appears more prone to the formation of “lack of melting” defects. This correlates nicely with the difference in thermal conductivity between the two materials. Thermal conductivity was also shown to increase strongly with increasing temperature. [less ▲]

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See detailGNSS observational bias in the frame of ionospheric studies
Wautelet, Gilles ULg; Warnant, René ULg

Poster (2014, November 17)

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See detailContrasting the role of Ih and ICaT currents in post-inhibitory rebound mechanisms in reciprocal-inhibitory networks
Dethier, Julie ULg; Drion, Guillaume; Sepulchre, Rodolphe

Poster (2014, November 16)

Models with reciprocal inhibition are ubiquitous in the literature. For instance, common rhythmic motor behaviors produced by central pattern generators (CPGs) involve half-center oscillators, which ... [more ▼]

Models with reciprocal inhibition are ubiquitous in the literature. For instance, common rhythmic motor behaviors produced by central pattern generators (CPGs) involve half-center oscillators, which consist of two inhibitory neurons that are not endogenous oscillators, but produce rhythmic outputs when reciprocally connected (Marder & Calabrese 1996). Models of thalamocortical spindle oscillations also suggest that the rhythm originates from the thalamic reticular nucleus, which consists in interacting inhibitory nonoscillatory neurons (Wang & Rinzel 1992). [less ▲]

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