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See detailAging mechanisms in amorphous GeTe
Raty, Jean-Yves ULg; Zhang, Wei; Luckas, Jennifer et al

Conference (2015, May 18)

Aging phenomena are common to all amorphous structures, but of special importance in phase change materials (PCM) since it impedes the realization of multi-level memories. Different interpretations have ... [more ▼]

Aging phenomena are common to all amorphous structures, but of special importance in phase change materials (PCM) since it impedes the realization of multi-level memories. Different interpretations have been proposed, but we focus here on the structural relaxation of amorphous GeTe, chosen because it is the simplest system that is representative of the wider class of GST alloys, lying along the GeTe-Sb2Te3 composition line of the GeSbTe phase diagram. We investigate the structure of amorphous GeTe using Density Functional Theory based Molecular Dynamics, using either the standard Generalized Gradient Approximation, or more elaborate Van der Waals approximation. New insight is provided on the stability of homopolar GeGe bonds and tetrahedral Ge bonding, in relation with the resistance drift phenomenon, that is investigated experimentally using photothermal deflection spectroscopy experiments [less ▲]

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See detailPolarization holography for vortex retarders recording: laboratory demonstration
Piron, Pierre ULg; Blain, Pascal ULg; Décultot, Marc ULg et al

in Applied Optics (2015), 54(15), 4765--4770

This paper will present a prototype of the first set of vortex retarders made of liquid crystal polymers recorded by polarization holography. Vortex retarders are birefringent plates characterized by a ... [more ▼]

This paper will present a prototype of the first set of vortex retarders made of liquid crystal polymers recorded by polarization holography. Vortex retarders are birefringent plates characterized by a rotation of their fast axis. Liquid crystals possess birefringent properties and they are locally orientable. Their orientation is defined by the perpendicular to the local orientation of the recording field. Polarization holography is a purely optical recording method. It is based on the superimposition of coherent and differently polarized beams. It is used to shape the electric field pattern to enable the recording of vortex retarders. The paper details the mathematical model of the superimposition process. The recording setup is exposed; it is characterized by a nearly common path interferometer. Two sets of measurements allowing the prediction of the retarder’s features are presented and compared. Finally, the experimentally recorded retarder is shown, its characteristics are investigated and compared to the predicted ones. [less ▲]

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See detailRheological behavior of β-Ti and NiTi powders produced by atomization for SLM production of open porous orthopedic implants
Yablokova, G.; Speirs, M.; Van Humbeeck, J. et al

in Powder Technology (2015)

The growing interest for Selective Laser Melting (SLM) in orthopedic implant manufacturing is accompanied by the introduction of novel Ti alloys, in particular β-Ti for their excellent corrosion ... [more ▼]

The growing interest for Selective Laser Melting (SLM) in orthopedic implant manufacturing is accompanied by the introduction of novel Ti alloys, in particular β-Ti for their excellent corrosion resistance as well as favorable combination of high mechanical strength, fatigue resistance and relatively low elastic modulus. As part of the SLM process for producing quality β-Ti parts powder flowability is essential to achieve uniform thickness of powder layers. In this work the flowability of different gas atomized β-Ti, including NiTi, powders has been studied. Their rheological properties were compared to those of commercially available plasma-atomized Ti–6Al–4V powder using a newly developed semi-automatic experimental set-up. Not only the particle size, shape and size distribution of the powders display a large influence on the powder flowability but also particle surface properties such as roughness, chemical composition and the presence of liquid on the surface of the particles. It was found that plasma or gas atomization production techniques for SLM powder have a considerable effect on the particle topography. Among the powders studied regarding SLM applicability only rheological properties of the fine size fraction (25–45 μm) of Ti–45Nb didn't conform to SLM processing requirements. To improve flowability of the Ti–45Nb powder itwas annealed both in air and argon atmosphere at 600 °C during 1 h, resulting in an improved rheological behavior suitable for SLM processing. [less ▲]

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See detailAuroral emissions at Jupiter and Saturn, at the crossroads of Astrophysics Geophysics and Plasma Physics
Grodent, Denis ULg

Conference (2015, May 13)

Auroral physics is at the intersection of more general fields of physics such as Astrophysics, Geophysics and Plasma Physics. In particular, the giant planets Jupiter and Saturn may be seen as slow ... [more ▼]

Auroral physics is at the intersection of more general fields of physics such as Astrophysics, Geophysics and Plasma Physics. In particular, the giant planets Jupiter and Saturn may be seen as slow rotating pulsars. For these two planets, there is a direct link between this pulsar-like behaviour and the auroral processes that are taking place in their atmosphere. We will take the example of Jupiter to illustrate haw the aurora is generated in the magnetosphere as a result of the volcanic activity of the moon Io. [less ▲]

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See detailFirst experimental realization of an Iron Magneto-Optical Trap
Bastin, Thierry ULg; Crauwels, Justine ULg; Huet, Nicolas ULg et al

Conference (2015, May 13)

Detailed reference viewed: 110 (9 ULg)
See detailValidation des méthodes analytiques: Approche basée sur l'erreur totale
Ziemons, Eric ULg; Hubert, Cédric ULg; Marini Djang'Eing'A, Roland ULg et al

Scientific conference (2015, May 12)

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See detailPrésentation de ModerNum
Regibeau, Julien ULg; Simon, Nicolas; Guri, Shipé

Conference (2015, May 08)

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See detailGrammaire matérielle et erreur de catégorie
Leclercq, Bruno ULg

Conference (2015, May 08)

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See detailEmbeddedness as a facilitator of sustainable entrepreneurship
Dufays, Frédéric ULg

Conference (2015, May 05)

This conceptual paper builds on stakeholder theory and the embeddedness argument to shift from the "what" to the "how" question on sustainable entrepreneurship. It shows that sustainable entrepreneurship ... [more ▼]

This conceptual paper builds on stakeholder theory and the embeddedness argument to shift from the "what" to the "how" question on sustainable entrepreneurship. It shows that sustainable entrepreneurship is a highly embedded process and that this high embeddedness facilitates the sustainability character of entrepreneurship. [less ▲]

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See detailCarte blanche: Nourrir la PLanète
Jijakli, Haissam ULg

Article for general public (2015)

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See detailLearning from blind tests: residues on grinding stones and flaked stone tools
Rots, Veerle ULg; Hayes, Elspeth; Cnuts, Dries ULg et al

Conference (2015, May)

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See detailStone tool use and hominin evolution
Fullagar, Richard; Rots, Veerle ULg

Conference (2015, May)

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See detailExpression of sexual ornaments in a polymorphic species: phenotypic variation in response to environmental risk
Winandy, Laurane ULg; Denoël, Mathieu ULg

in Journal of Evolutionary Biology (2015), 28(5), 1049-1056

Secondary sexual traits may evolve under the antagonistic context of sexual and natural selection. In some polymorphic species, these traits are only expressed during the breeding period and are ... [more ▼]

Secondary sexual traits may evolve under the antagonistic context of sexual and natural selection. In some polymorphic species, these traits are only expressed during the breeding period and are differently expressed in alternative phenotypes. However, it is unknown whether such phenotypes exhibit phenotypic plasticity of seasonal ornamentations in response to environmental pressures such as in the presence of fish (predation risk). This is an important question to understand the evolution of polyphenisms. We used facultative paedomorphosis in newts as a model system because it involves the coexistence of paedomorphs that retain gills in the adult stage with metamorphs that have undergone metamorphosis, but also because newts exhibit seasonal sexual traits. Our aim was therefore to determine the influence of fish on the development of seasonal ornamentation in the two phenotypes of the palmate newt (Lissotriton helveticus). During the entire newt breeding period, we assessed the importance of phenotype and fish presence with an information-theoretic approach. Our results showed that paedomorphs presented much less developed ornamentation than metamorphs and those ornamentations varied over time. Fish inhibited the development of sexual traits but differently between phenotypes: in contrast to metamorphs, paedomorphs lack the phenotypic plasticity of sexual traits to environmental risk. This study points out that internal and external parameters act in complex ways in the expression of seasonal sexual ornamentations and that similar environmental pressure can induce a contrasted evolution in alternative phenotypes. [less ▲]

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See detailSearching for early traces of fire production on flint tools
Sorensen, Andrew; Rots, Veerle ULg

Conference (2015, May)

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See detailThe stadium of Olympia: a dialogical composition
Kiuri, Miranda; Teller, Jacques ULg

in Montanola, J (Ed.) International Journal Arquitectonics: Architecture, phenomenology & social dialogics (2015)

The article proposes a renewed interpretation of the relation of the antique stadium of Olympia with its built environment. It is argued that the stadium, far from being isolated from the city as commonly ... [more ▼]

The article proposes a renewed interpretation of the relation of the antique stadium of Olympia with its built environment. It is argued that the stadium, far from being isolated from the city as commonly considered, was connected to the Altis through a series of visual relations, adopting principles of dialogical architecture: composition, significant location, functional routes, perceptions, role of architectonic elements and spatial characteristics. This argument is illustrated through computer-generated perspectives of the stadium. [less ▲]

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See detailGeoarchaeology of the ancient city of Utica (Tunisia) and evolution of the palaeoenvironment of the Medjerda delta
Pleuger, Elisa ULg; Abichou, Hakim; Gadhoum, Ahmed et al

Poster (2015, May)

Phoenician Utica remains today largely unknown, as is its role in the Phoenician expansion in the western Mediterranean. Aristotle and Pliny the Elder mention Utica as a maritime and port city and ... [more ▼]

Phoenician Utica remains today largely unknown, as is its role in the Phoenician expansion in the western Mediterranean. Aristotle and Pliny the Elder mention Utica as a maritime and port city and estimate its origin around the 11th c. BC. However, in the present state of research, no archaeological evidence is earlier than the 9th c. BC, and the location of the Phoenician and Roman port infrastructures remains unknown. Today, the ancient city is located on a promontory in the heart of the Medjerda delta, 10 km inland. This project proposes an interdisciplinary effort to understand the Medjerda delta landscape changes during the Holocene. It starts from an archaeological problem and proposes the contribution of geoarchaeology to the understanding of the relationship between ancient societies and their environment. The fluvial palaeoenvironments and sedimentary processes are studied through the mechanical extraction of cores (15-20 m deep) to reach the early Holocene. Selected sediment samples are then studied in laboratory, using different and complementary approaches. The location of port infrastructures will bring initial answers to the question of the foundation of the city. The study of river palaeoenvironments of the Medjerda delta during the Holocene aim at a better understanding of the nature of the settlement, as well as the function of the city of Utica over time. This study will also assess the impact of the ancient city on the environment and understand how the city adapted to the mobility of this Mediterranean delta. Furthermore, the analysis of sedimentary processes causing the filling of the harbour basin will lead to speculation about the causes of the abandonment of the structures and more generally the decline of the city in favor of Carthage. It will also examine whether natural or anthropogenic factors have influenced this deltaic progradation over the centuries. [less ▲]

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See detailBeam to concrete-filled rectangular hollow section column joints using long bolts
Hoang, Van Long ULg; Demonceau, Jean-François ULg; Jaspart, Jean-Pierre ULg

in Proceedings of the 15th international symposium on tubular structures - ISTS15 (2015, May)

This paper presents a research on a specific type of unstiffened extended end-plate joint used to connect I-shaped beams to concrete-filled rectangular hollow section columns. The main idea is to use long ... [more ▼]

This paper presents a research on a specific type of unstiffened extended end-plate joint used to connect I-shaped beams to concrete-filled rectangular hollow section columns. The main idea is to use long bolts throughout the column to connect the beam end-plates, so avoiding intermediate connecting elements (e.g. a reverse U channel) or special bolts (e.g. blind bolts). However, the use of long bolts for beam-to-column connections is still rare in the construction and no design procedure exists in the Eurocodes; this justifies the pre-sent research. Firstly, a test program within a RFCS European project titled HSS-SERF “High Strength Steel in Seismic Resistant Building Frames”, 2009-2013 was performed. In this project, specimens subjected to sig-nificant bending moments (and shear) or to shear only was defined. Then, analytical developments based on the component approach and aimed at predicting the joint response have been carried out; their validity is demonstrated through comparisons with the tests. Finally, design guidelines have been provided. [less ▲]

Detailed reference viewed: 152 (25 ULg)