Last 7 days
Bookmark and Share    
Full Text
See detailLand erosion and associated evolution of clay minerals assemblages in Mediterranean region (Southern Turkey): Amik Lake
El Ouahabi, Meriam ULg; Hubert, Aurelia ULg; Lebeau, Helene et al

Poster (2015, July)

Under Mediterranean context, continuous human occupation is attested in the Amik Basin (southern Turkey) since 6000-7000 BC. The Basin also is crossed by The Dead Sea Fault (DSF), a major neotectonic ... [more ▼]

Under Mediterranean context, continuous human occupation is attested in the Amik Basin (southern Turkey) since 6000-7000 BC. The Basin also is crossed by The Dead Sea Fault (DSF), a major neotectonic structure in the Middle East extending from the Red Sea in the south to the East Anatolian Fault Zone in the north. The study focuses on the mineralogy and clay mineralogy record of the Amik Lake occupying the central part of the Basin. Our objective is to constrain major mineralogical and clay minerals evolution in the area over the last 4000 years and assess changes that would be related to the different land uses during the different Bronze, Roman, Ottoman and Modern civilizations. Sediments were collected at 1 to 2 cm intervals in core sediments up to a depth of 6 meters in the clay deposits. Geochemistry (XRF), mineralogy (XRD) and clay mineralogy are applied to study the sediment records. The age of the record is constrained combining radionuclide and radiocarbon dating. Chemical and mineralogical composition of sediments is quite diversified reflecting the significant geological variation of drainage basins. Abundant mixed-layer and partly disordered minerals characterize the different sedimentary levels recorded in those cores. Levels relatively rich in chlorite, illite and quartz are interpreted as corresponding to relatively dry periods, while more humid periods lead to more intensive weathering and consequently to the dominance of clay minerals more advanced in the relative stability scale, such as kaolinite. Smectite is taken to indicate a climate with contrasting seasons and a pronounced dry season. The sedimentary record clearly shows two periods indicating strong soil erosion in the Lake catchment. The most recent erosion phase is modern. The oldest one would have started during the late Bronze period and lasted until the late Roman Period. The first and older period is attributed to a strong aggradation linked to major increase in erosion. Our study shows that this episode has specific characteristics: mixed-layer clay mineral, high percent in Ni, Cr and Mg coupled with significant amount of organic matter of terrestrial origin. Ni and Mg most probably come from the Amanos Mountains an ophiolitic belt indicating an intensive upland cultivation and possible exploitation of its mineral resource. The second period is attributed to the modern period. The signature of the increase in erosion is different, because most of the soil cover has already been eroded. Only a patchy thin and unmature soil cover exists since the Late Roman time. Erosion is associated with a marked increase of smectite-illite interstratified clay, goethite and hematite found in deep soil horizons. Moreover, a marked increase in Cr is showed and is probably related to an enhanced exploitation of its mineral resource and to a renew land exploitation of the Amanos Mountain Range. [less ▲]

Detailed reference viewed: 24 (0 ULg)
Full Text
See detailCarbides and grain size quantification methods in high speed steel alloys
Tchuindjang, Jérôme Tchoufack ULg; Paydas, Hakan ULg; Hashemi, Seyedeh Neda ULg et al

Conference (2015, July)

High speed steel (HSS) grades are widely used as in highly stressed applications where carbides content promote enhanced mechanical properties together with oxidation and wear resistances. Such a ... [more ▼]

High speed steel (HSS) grades are widely used as in highly stressed applications where carbides content promote enhanced mechanical properties together with oxidation and wear resistances. Such a tribological behaviour is mainly due to the presence of primary carbides. It is thus important to quantify the carbide volume fraction in HSS to correlate this result with the mechanical and tribological properties of the materials. Depending of the steel composition several types of carbides are precipitated in HSS: MC (Nb and V-rich), M2C (Mo and W-rich), Cr-rich M7C3 and some others, depending of the chemical composition. Two groups of HSS were analyzed in this study: cast HSS manufactured by centrifugal casting and cladded HSS manufactured by laser cladding. Depending on the chemical composition and the manufacturing process of the studied material, several methods have been used to quantify the carbide volume fraction and the grain size. [less ▲]

Detailed reference viewed: 8 (1 ULg)
Full Text
See detailDevelopment of quantification methods applied to HSS alloys for carbides volume fraction and grain size assessments
Tchuindjang, Jérôme Tchoufack ULg; Paydas, Hakan ULg; Hashemi, Seyedeh Neda ULg et al

Poster (2015, July)

High speed steels (HSS) are used in applications where enhanced mechanical properties together with hot oxidation and wear resistances are required. Such an improved physico-chemical behaviour is mainly ... [more ▼]

High speed steels (HSS) are used in applications where enhanced mechanical properties together with hot oxidation and wear resistances are required. Such an improved physico-chemical behaviour is mainly due to the presence of primary carbides within the microstructure. Depending of the initial chemical composition several types of carbides can precipitate in HSS such as MC (Nb and V-rich), M2C (Mo and W-rich), Cr-rich M7C3, etc. Two groups of HSS were analysed in this study, which are the so-called cast HSS grades that are manufactured by a centrifugal casting process and the cladded HSS manufactured by laser cladding. Purpose: Quantify the carbide volume fractions and the grain size within HSS grades in order to set correlations between the microstructure and both the mechanical and the tribological properties of the materials. Findings: The metallurgical features such as carbides nature and shape have been determined that are related to the manufacturing process of the studied material, and several methods have been used to quantify the carbide volume fractions and to assess the grain size. [less ▲]

Detailed reference viewed: 9 (1 ULg)
Full Text
Peer Reviewed
See detailIdentification of the main parameters controlling the plasticity of ceramic pastes: The case study of the Marrakech region (Morocco)
El Idrissi, Hicham; Fontaine, François ULg

Poster (2015, July)

Numerous traditional ceramic workshops occur within a range of 10 to 80 km around the city of Marrakech. Our study aims to identify the main parameters controlling the plasticity of pastes used by the ... [more ▼]

Numerous traditional ceramic workshops occur within a range of 10 to 80 km around the city of Marrakech. Our study aims to identify the main parameters controlling the plasticity of pastes used by the artisans. To reach this goal, we characterize by X-ray diffraction, granulometry and plasticity index (PI) the local raw clayey material. The investigation of 26 whole pastes shows the dominance of quartz (20 to 50%) and clay minerals (25 to 60%) with K-feldspar (2 to 17%), plagioclase (2 to 25%), calcite (0 to 18%), dolomite (0 to 15%), goethite (0 to7%) and trace of hematite and anhydrite (< 3%). Amphibole occurs in trace (< 5%) but only in some samples. The clay minerals are diversified, including illite (10 to 40%), kaolinite (2 to 15%), mixed-layer (ML) (0 to 10%), smectite, vermiculite and chlorite (0 to 5%), and pyrophyllite-talc association (0 to 8%). Sepiolite (12%) is only present in one paste. The grain size is made by variable proportions of sand (5 to 65%), silt (12 to 53%) and clayey fraction (18 to 66%). The Plasticity index (PI) indicates the presence of two principals groups of pastes. (1) The first group is characterized by PI values ranging between 15 to 18. Their moderate plasticity behavior is related either to the low rate of clayey fraction and/or to the absence of plastic clays like smectites and mixed layer with smectitic sheets. (2) The PI of second group ranges between 20 to 32. The high plasticity values are influenced by the presence of specific clayey minerals like talc-pyrophyllite or sepiolite, or by the high content of smectite plus smectitic mixed-layers within the clayey (< 2 micron) fraction. Only one sample without any of these plastic minerals but with a high content of clayey fraction is characterized by a high PI value (24). We concluded that the workability of ceramic paste in Marrakech region is controlled by a combination of factors, dominated by the grain size distribution and the content in plastic clay minerals within the fine fraction. [less ▲]

Detailed reference viewed: 14 (0 ULg)
Full Text
See detailA ROBUST APPROACH OF TOPOLOGIC OPTIMIZATION OF MECHANICAL AND AERONAUTICAL COMPONENTS FABRICATED BY ADDITIVE MANUFACTURING
Bauduin, Simon ULg

in Bauduin, Simon (Ed.) Poster : A ROBUST APPROACH OF TOPOLOGIC OPTIMIZATION OF MECHANICAL AND AERONAUTICAL COMPONENTS FABRICATED BY ADDITIVE MANUFACTURING (2015)

Detailed reference viewed: 20 (2 ULg)
Full Text
See detailMarcel-Henri Jaspar, "Le plus gaullien des Belges" ? Construction et déconstruction d'une réputation (1940-1966)
Genin, Vincent ULg

in Lanneau, Catherine; Depagie, Francis (Eds.) De Gaulle et la Belgique (2015, July)

Detailed reference viewed: 23 (4 ULg)
Full Text
Peer Reviewed
See detailLa Belgique ‘officielle’ face à l’OAS (1961-1964). Cas d’une adaptation de Bruxelles à la politique du général De Gaulle
Genin, Vincent ULg

in Revue du Nord (2015), 406 (octobre-décembre 2014)(96), 917-935

Detailed reference viewed: 15 (1 ULg)
Full Text
Peer Reviewed
See detailLe remplacement des F-16 belges : la dimension nucléaire
Dumoulin, André ULg

in Revue Défense Nationale (2015)

l'article aborde la question du remplacement des F-16 belges avec ou sans le critère d'emport des armes nucléaires aéroportées B-61 américaines

Detailed reference viewed: 42 (0 ULg)
Full Text
See detailCeci n’est pas un conseil !
Choffray, Jean-Marie ULg

E-print/Working paper (2015)

La « Grande Récession de 2008 » a un mérite. Un seul ! Elle a rendu public le fait que personne ne savait exactement ce qui s’était passé, ni ce qui se passait. Pourquoi une telle crise de confiance avait ... [more ▼]

La « Grande Récession de 2008 » a un mérite. Un seul ! Elle a rendu public le fait que personne ne savait exactement ce qui s’était passé, ni ce qui se passait. Pourquoi une telle crise de confiance avait-elle vu le jour ? Quelles en seraient les conséquences ? Toutes et tous se sont trompés, y compris les meilleurs. Même celles et ceux qui étaient convaincus d’avoir raison ! Plus que jamais, l’incertitude, la saine et souveraine incertitude, garantit la liberté de l’investisseur... et du professeur ! [less ▲]

Detailed reference viewed: 1670 (108 ULg)
Full Text
Peer Reviewed
See detailInfluence of thermal expansion mismatch on residual stress profile in veneering ceramic layered on zirconia: Measurement by hole-drilling.
Mainjot, Amélie ULg; Najjar, Achref; Jakubowicz-Kohen, Boris D. et al

in Dental materials : official publication of the Academy of Dental Materials (2015)

OBJECTIVES: Mismatch in thermal expansion coefficient between core and veneering ceramic (Deltaalpha=alphacore-alphaveneer, ppm/ degrees C) is reported as a crucial parameter influencing veneer fractures ... [more ▼]

OBJECTIVES: Mismatch in thermal expansion coefficient between core and veneering ceramic (Deltaalpha=alphacore-alphaveneer, ppm/ degrees C) is reported as a crucial parameter influencing veneer fractures with Yttria-tetragonal-zirconia-polycrystal (Y-TZP) prostheses, which still constitutes a misunderstood problem. However, the common positive Deltaalpha concept remains empirical. The objective of this study is to investigate the Deltaalpha dependence of residual stress profiles in veneering ceramic layered on Y-TZP frameworks. METHODS: The stress profile was measured with the hole-drilling method in bilayered disc samples of 20mm diameter with a 0.7mm thick Y-TZP framework and a 1.5mm thick veneer layer. 3 commercial and 4 experimental veneering ceramics (n=3 per group) were used to obtain different Deltaalpha varying from -1.3ppm/ degrees C to +3.2ppm/ degrees C, which were determined by dilatometric analyses. RESULTS: Veneer fractures were observed in samples with Deltaalpha>/=+2.3 or </=-0.3ppm/ degrees C. Residual stress profiles measured in other groups showed compressive stresses in the surface, these stresses decreasing with depth and then becoming more compressive again near the interface. Small Deltaalpha variations were shown to induce significant changes in residual stress profiles. Compressive stress near the framework was found to decrease inversely to Deltaalpha. SIGNIFICANCE: Veneer CTE close to Y-TZP (+0.2ppm/ degrees C Deltaalpha) gived the most favorable stress profile. Yet, near the framework, Deltaalpha-induced residual stress varied inversely to predictions. This could be explained by the hypothesis of structural changes occurrence within the Y-TZP surface. Consequently, the optimum Deltaalpha value cannot be determined before understanding Y-TZP's particular behavior when veneered. [less ▲]

Detailed reference viewed: 24 (5 ULg)
Full Text
Peer Reviewed
See detailFlora and fauna from a new Famennian (Upper Devonian) locality at Becco, eastern Belgium
Olive, Sébastien; Clément, Gaël; Denayer, Julien ULg et al

in Geologica Belgica (2015), 18(2-4), 92-101

The Becco locality (Liège province), belongs to the Theux tectonic window and represents a proximal, probably fluvial, environment corresponding to a channel infill. We present here a preliminary report ... [more ▼]

The Becco locality (Liège province), belongs to the Theux tectonic window and represents a proximal, probably fluvial, environment corresponding to a channel infill. We present here a preliminary report of the fossil assemblage discovered at the locality. The Becco site has yielded a diverse flora of early seed plants including Moresnetia zalesskyi, Dorinnotheca streeli and Condrusia sp. This assemblage, characteristic of the Belgian Famennian, highlights the diversity of early spermatophytes in the country. Becco has also delivered a rich vertebrate fauna with antiarch, groenlandaspid and phyllolepid placoderms, diplacanthiform acanthodians, as well as actinopterygians and various sarcopterygians. The fossiliferous assemblage of Becco resembles those of several Devonian tetrapod- bearing localities, including that of Strud in Belgium, and could therefore provide a favorable palaeoecological setting in the search for early tetrapods. [less ▲]

Detailed reference viewed: 24 (5 ULg)
See detailIntégration de tablettes numériques dans la formation des futurs enseignants: une étude de cas
Parlascino, Emmanuelle ULg; Joris, Noémie ULg

Conference (2015, July)

À travers cette recherche, les auteurs visent à mettre en évidence, chez les étudiants, les apports réels, en termes d’apprentissages et de développement professionnel, de situations d’enseignement ... [more ▼]

À travers cette recherche, les auteurs visent à mettre en évidence, chez les étudiants, les apports réels, en termes d’apprentissages et de développement professionnel, de situations d’enseignement intégrant une technologie, à savoir les tablettes numériques. Le groupe d’étude se constitue d’un enseignant en histoire en haute école pédagogique et de trois classes d’étudiants en formation pour devenir enseignants. Ce groupe fera l’objet d’une analyse approfondie au travers d’observations filmées, examinées à l’aide de grilles, et de commentaires réflexifs (de l’enseignant et des étudiants) issus d’entretiens d’autoconfrontation sur divers extraits des situations d’enseignement menées et vécues. Cette méthodologie conduira à croiser plusieurs types d’informations : (1) les objectifs de l’enseignant au moment de préparer la situation d’enseignement, (2) sa perception des apports mis en place à travers la technologie, (3) la perception de ses étudiants et (4) les observations des auteurs. Soucieux de contribuer à l’analyse réflexive sur l’intérêt d’intégrer le numérique en éducation, les auteurs veulent mettre en évidence les apports réels de l’activité, les points de passage obligés et les principales difficultés de sa mise en place. Ces résultats pourront éclairer les enseignants souhaitant se lancer dans ce genre d’activité innovante. [less ▲]

Detailed reference viewed: 43 (5 ULg)
See detail"On se débrouille", or how to be a good judge when the state lets you down?
Andreetta, Sophie ULg; Kolloch, Annalena

Conference (2015, July)

Over the last couple of years, Beninese magistrates have been on strike for months in a row. In 2012, it was about the Ministry of justice implying corruption issues. In 2013, it was about independence ... [more ▼]

Over the last couple of years, Beninese magistrates have been on strike for months in a row. In 2012, it was about the Ministry of justice implying corruption issues. In 2013, it was about independence and fear of political infringement. In 2014, it was about the most recent appointments. When it comes to judges from the bench, most of them complain about their substantial workload, low pay and poor working conditions. They also highlight the discrepancies between the magistrate’s social status and what their families expect from them, the standards of living that people assume that they have. In short, there seems to be a professional malaise within the Beninese bench, who feel like the state is letting them down, yet judges also insist on the importance of their work, and of doing it right. This is why, for the purpose of this paper, we will be looking at the discourses and representations of Beninese judges on their own social and professional status. What does it mean to be a judge in Benin today? Why do young lawyers choose that professional path over other legal careers? How do they ‘do their job right’ and what are the obstacles to it? Considering both age and gender, we are also trying to look at what it means to be a civil servant today, when the state is no longer the only – or the most promising – employer for legal practitioners. [less ▲]

Detailed reference viewed: 14 (1 ULg)
Full Text
See detailTentatives de prétraitement des granulats recyclés pour l’amélioration des bétons préfabriqués
Zhao, Zengfeng ULg; Courard, Luc ULg; Remond, Sébastien et al

in Ciments, bétons et fibres - Matériaux et structures (2015, July)

De très grandes quantités de déchets de construction et de démolition sont produites chaque année. Jusqu'à présent, seule une petite fraction de ces déchets de béton est réutilisée sous forme de granulats ... [more ▼]

De très grandes quantités de déchets de construction et de démolition sont produites chaque année. Jusqu'à présent, seule une petite fraction de ces déchets de béton est réutilisée sous forme de granulats pour la fabrication de béton. Afin de faire bon usage des granulats recyclés (GR) dans le béton, il est très important d’améliorer leurs propriétés. Dans cette étude, une méthode de traitement des GR au moyen d’une carbonatation accélérée en laboratoire et des méthodes de traitement par modification de l’état de surface des GR ont été étudiées. Les résultats montrent qu'après la carbonatation accélérée au laboratoire, la teneur en pâte de ciment durcie des GR mesurée par dissolution de l'acide salicylique diminue, que la densité et la surface spécifique des GR augmentent et que la porosité des GR diminue, ce qui conduit à la réduction de l'absorption d'eau des GR. Des agents hydrofuges à base de silane ont également été étudiés et semblent diminuer l’absorption d’eau par les GR. [less ▲]

Detailed reference viewed: 17 (1 ULg)
See detailProcessus de radicalisation et milieu scolaire
Garcet, Serge ULg

Diverse speeche and writing (2015)

Intervention dans une conférence-débat sur la place de l'école dans les processus de radicalisation islamique chez les jeunes en fédération Wallonie-Bruxelles.

Detailed reference viewed: 29 (1 ULg)
Full Text
Peer Reviewed
See detailComparative study of different output metrics for a three weakly coupled resonator sensor
Zhao, Chun; Wood, Graham; Xie, J.B. et al

in Proceedings of Solid-State Sensors, Actuators and Microsystems (Transducers 2015) (2015, July)

This work, for the first time, investigates the characteristics of different output metrics for a three degree-of-freedom (DoF) coupled resonator sensor. The main aspects examined are sensitivity and ... [more ▼]

This work, for the first time, investigates the characteristics of different output metrics for a three degree-of-freedom (DoF) coupled resonator sensor. The main aspects examined are sensitivity and linear range. It is shown from electrical measurements that using the vibration amplitude ratio as an output signal provides improved sensitivity and linearity range, compared to other methods such as shift in eigenstate, mode frequency or amplitude difference. [less ▲]

Detailed reference viewed: 21 (2 ULg)
Peer Reviewed
See detailSharing a Car? Yuck, No! An Investigation of Customer Contamination in Access-Based Services
Hazee, Simon ULg; Delcourt, Cécile ULg; Van Vaerenbergh, Yves

Conference (2015, July)

Detailed reference viewed: 18 (2 ULg)