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See detailAcromegaly-Journey from the Specific to the General
BECKERS, Albert ULiege

Scientific conference (2017, September 08)

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See detailA method for hybrid fire testing: Development, implementation and numerical application
Sauca, Ana ULiege; Mergny, Elke ULiege; Gernay, Thomas ULiege et al

in Gillie, Martin; Wang, Yong (Eds.) Proceedings of ASFE 2017 Conference (2017, September 08)

Hybrid Fire Testing (HFT) is a technique that allows assessing experimentally the fire performance of a structural element under real boundary conditions that capture the effect of the surrounding ... [more ▼]

Hybrid Fire Testing (HFT) is a technique that allows assessing experimentally the fire performance of a structural element under real boundary conditions that capture the effect of the surrounding structure. To enable HFT, there is a need for a method that is unconditionally stable, ensures equilibrium and compatibility at the interface and captures the global behaviour of the analysed structure. A few attempts at conducting HFT have been described in the literature, but it can be shown, based on the analytical study of a simple one degree-of-freedom elastic system, that the considered method was fundamentally unstable in certain configurations which depend on the relative stiffness between the two substructures, but which cannot be easily predicted in advance. In this paper, a new method is introduced to overcome the stability problem and it is shown through analytical developments and applicative examples that the stability of the new method does not depend on the stiffness ratio between the two substructures. The new method is applied in a virtual hybrid test on a 2D reinforced concrete beam part of a moment resisting frame, showing that stability, equilibrium and compatibility are ensured on the considered multiple degree-of-freedom system. Besides, the virtual HFT succeeds in reproducing the global behaviour of the analysed structure. The method development and implementation in a virtual (numerical) setting is described, the next step being its implementation in a real (laboratory) hybrid test. [less ▲]

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See detailCreativity and Innovation
Artige, Lionel ULiege

Conference (2017, September 08)

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See detailThe γ Dor stars as revealed by Kepler: A key to reveal deep-layer rotation in A and F stars
Salmon, Sébastien ULiege; Ouazzani, R.-M.; Antoci, V. et al

in EPJ Web of Conferences (2017, September 08), 152

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See detailAdaptive capacity assessment of damselfishes (Pomacentridae)
Gajdzik, Laura ULiege

Doctoral thesis (2017)

Assessing the multiple facets of adaptive capacity is a core issue as it reflects species' ability to cope with variations in environmental conditions. Within the threatened coral reefs, the Pomacentridae ... [more ▼]

Assessing the multiple facets of adaptive capacity is a core issue as it reflects species' ability to cope with variations in environmental conditions. Within the threatened coral reefs, the Pomacentridae (damselfishes) represent a very suitable model to undertake such issue. Damselfishes are one of the most ecologically dominant reef fish families whose lineages repeatedly radiated across convergent trophic strategies. These strategies comprise (1) pelagic feeders (mainly picking zooplankton in the water column), (2) benthic feeders (essentially feeding on algae and vagile invertebrates on the benthos) and (3) an intermediate group (foraging in the entire bentho–pelagic compartment). To date, most studies compared the degree of vulnerability between specialists and generalists because the first ones are thought to have a higher risk of extinction. The tripartite trophic guild system in Pomacentridae provides the opportunity to step out of the binary "specialist–generalist" classification and to robustly grasp the adaptive capacity by focusing on fundamental units in assemblages. In the present thesis, I estimated the ecology of damselfishes by quantifying their eco–functional diversity (including trophic, habitat and behavioural diversity and also the ecosystem functions they performed) and by gauging their abiotic (i.e. species–environment relationship) and biotic (i.e species–species relationship) interactions. Ecological results revealed (a) the systematic presence of the three main trophic guilds in each assemblage, and (b) a consistent pattern of species eco–functional niches that are highly differentiated and evenly distributed in eco–functional spaces of similar size, but they provided (c) limited support for any degree of trophic plasticity (i.e. little evidence for any geographic variation in the diet of widespread species). The trophic guilds were also functionally dissimilar and displayed different levels of functional diversity. The intermediate group was the least functionally diverse guild with the lowest functional redundancy, while opposite findings were found for the pelagic–feeding guild. Then, I quantified the genetic diversity, which varied among trophic guilds and was associated with variation in their trophic ecology and habitat–behavioural traits (e.g. pelagic feeders have the lowest genetic and ecological diversity). Using a phylogenetic framework, I found that functional traits were evolutionarily labile and accumulated at a similar rate within the three trophic guilds. Transition rates among guilds were also biased, suggesting differences in the evolvability. The evaluation of all of these components indicated that some processes occurring at an "ecological" timescale and others at an "evolutionary" timescale had concordant effects (e.g. the coupling between levels of genetic and ecological diversity supported by the evolvability result for the intermediate group), although sometimes one type of process had more important effects (e.g. the principle of competitive exclusion probably shaped the high functional diversity of pelagic feeders). Overall, I demonstrated that the adaptive capacity of Pomacentridae is bounded and that trophic guilds are not equal in the face of environmental changes. The case of pelagic feeders illustrates a scenario wherein evolution and the right environmental conditions led to the success of a given group, but their persistence may be jeopardized by a low genetic diversity. The two other guilds possess more intrinsic assets (e.g. less restricted habitat and dietary requirements) to adapt. Given the uncertainty regarding the pace at which evolutionary processes will occur and the potential imperilment of evolvability to act as a source of future diversity, the ability to diversify along many niche axes associated with broad intrinsic characteristics (i.e. higher genetic diversity) may help organisms to sustain themselves in a long–term perspective and to maintain more ecosystem functions. [less ▲]

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See detailComparative fire analysis of steel-concrete composite buildings designed following performance-based and U.S. prescriptive approaches
Elhami Khorasani, Negar; Fang, Chenyang; Gernay, Thomas ULiege

in Gillie, Martin; Wang, Yong (Eds.) Proceedings of ASFE 2017 Conference (2017, September 08)

Performance-based structural fire design provides a rational methodology for designing modern buildings with cost-effective solutions. However, in the United States, fire design still largely relies on ... [more ▼]

Performance-based structural fire design provides a rational methodology for designing modern buildings with cost-effective solutions. However, in the United States, fire design still largely relies on design at the component level using prescriptive approaches. With performance-based approaches, there is an opportunity to benefit from increased flexibility and reduced cost in the design, but these advantages need to be explicitly described and disseminated to promote this shift in paradigm. In this paper, a comparative analysis is conducted on multi-story steel-concrete buildings designed following performance-based and U.S. prescriptive approaches. The steel-concrete composite structure allows taking advantage of tensile membrane action in the slab during fire, and therefore removing the fire protection on secondary beam elements. The nonlinear finite element software SAFIR is used to model the behavior of the buildings under the standard ASTM fire and a natural fire determined using the two-zone fire model CFAST. The numerical simulations show that performance-based design can be used to achieve the required level of safety currently enforced in the U.S. prescriptive guidelines, while providing an opportunity for cost reduction in fire protection material. [less ▲]

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See detailSensitivity of elevated temperature load carrying capacity of thin-walled steel members to local imperfections
Maraveas, Chrysanthos ULiege; Gernay, Thomas ULiege; Franssen, Jean-Marc ULiege

in Gillie, Martin; Wang, Yong (Eds.) Proceedings of ASFE 2017 Conference (2017, September 07)

The local buckling capacity of fire exposed thin-walled steel cross sections is affected by the reduction in strength and stiffness due to elevated temperatures and by the amplitude of the initial local ... [more ▼]

The local buckling capacity of fire exposed thin-walled steel cross sections is affected by the reduction in strength and stiffness due to elevated temperatures and by the amplitude of the initial local imperfections. Several researchers have proposed design methods to calculate the capacity of these steel members at elevated temperatures, but they used different methodologies and different amplitude of local imperfections in the extensive numerical analyses that are typically at the base of these methods. This variability in hypotheses happens because there is no clear provision defining the local imperfection amplitude for fire design in the codes (European or US). EN 1993-1-5 proposes amplitude values of local imperfections for ambient temperature design, while EN 1090-2 defines a -different- maximum allowed size of fabrication tolerance during production. Meanwhile, other sizes of local imperfections have also been proposed in the literature, with values different than those from EN 1993-1-5 and EN 1090-2. This paper reviews the existing code provisions and compares the existing design models and their assumptions for thin-walled steel cross sections. Finite element analyses are then conducted on isolated steel plates at elevated temperatures to investigate the effect of local imperfections. Finally, specific amplitude of local imperfections is proposed for fire design of thin-walled steel members. [less ▲]

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See detailAdvanced oxidative treatment for waste water contamined by pharmaceutical products
Belet, Artium ULiege; Vreuls, Christelle; Gillard, Nathalie et al

Poster (2017, September 07)

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See detailOptimization of hydroxyapatite synthesis via sol-gel process for bone reconstruction application
Tilkin, Rémi ULiege; Regibeau, Nicolas ULiege; Grandfils, Christian ULiege et al

Poster (2017, September 07)

During the past few years, tissue engineering has become one of the most promising techniques to maintain, improve, or reconstruct human tissue, even complete human organs. This solution is frequently ... [more ▼]

During the past few years, tissue engineering has become one of the most promising techniques to maintain, improve, or reconstruct human tissue, even complete human organs. This solution is frequently based on the realization of temporary porous matrices, also called "scaffolds". Scaffolds are highly porous matrices notably designed to structure the development of cells, but also to guarantee the function of the implant during the regeneration process. Several materials have been proposed for the conception of scaffold. These have to meet strict criteria regarding biocompatibility, degradability, mechanical and surface properties. As a result of their biomimetism, bioceramics, like hydroxyapatite (Ca5(PO4)3(OH)), have been widely developed during the past few years for bone reconstruction. The aim of this study is the optimization of the synthesis of hydroxyapatite by sol-gel process to be used in the conception of scaffold for bone reconstruction application. In this optic, powder obtained from two synthesis processes (wet precipitation and sol-gel process) were compared with commercial hydroxyapatite. For wet precipitation process, calcium nitrate and phosphoric acid were used as reagent. For sol-gel process, calcium acetate was used as the source of calcium and triethylphosphate as the source of phosphate. Reagents were mixed and the solution was aged. The powder was then dried and sintered. Finally, particles were washed in HCl to remove CaO and then dried. Those new materials were characterized, particularly in terms of chemical composition (XRD, FTIR), crystallinity (XRD), morphology (SEM, TEM), size (TEM, DLS) and Ca/P ratio (EDX). [less ▲]

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See detailLaterality patterns for Gestalts of language
Dumitru, Magdalena ULiege; Van Calster, Laurens ULiege; Bouffier, Marion ULiege et al

Poster (2017, September 07)

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See detailValidation of a TEOS based sol-gel coating for the protection of carbon fibres against oxidation regarding their use in metal matrix composites
Montrieux, Henri-Michel ULiege; Lecomte-Beckers, Jacqueline ULiege; Halleux, Jacques et al

Poster (2017, September 07)

The use of sol-gel coating on graphite substrates has sucessfuly been done. In particular, in the field of metal matrix composites, some authors state that the use and cure of TEOS sol-gel on carbon based ... [more ▼]

The use of sol-gel coating on graphite substrates has sucessfuly been done. In particular, in the field of metal matrix composites, some authors state that the use and cure of TEOS sol-gel on carbon based fibres may improve the liquid magnesium infiltration. The described mechanism is the lowering of the liquid/solid contact angle under some specific conditions of time and temperature by the occurrence of a metal-oxide exothermal chemical reaction. Furthermore the application of silica based sol-gels on carbon fibres in order to control the medium to high temperature oxidation of fibres preforms is less investigated. The primary objective is to understand more deeply the oxidation of some uncoated fibres by the comparison of ESEM observations to TGA/ATD curves. The secondary objective is to formulate and coat a TEOS based sol-gel on T300 carbon fibres and to evaluate the new oxidation behaviour. The ternary objective is to measure in a simple way the gain of oxidation resistance of some coated fibres. [less ▲]

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See detailMagneto-optical investigation of superconducting hybrid structures
Brisbois, Jérémy ULiege

Doctoral thesis (2017)

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See detailCatalytic reforming of biomass gasification tars with bimetallic catalysts
Wolfs, Cédric ULiege; Claude, Vincent; Lambert, Stéphanie ULiege

Poster (2017, September 07)

The thermochemical method called “biomass gasification” is generating emphatic interest for the production of bio-Syngas (CO+H2) since this process presents the advantage of being renewable without ... [more ▼]

The thermochemical method called “biomass gasification” is generating emphatic interest for the production of bio-Syngas (CO+H2) since this process presents the advantage of being renewable without emitting CO2. However, in practical applications, there are still some technical problems due to high concentration of tars in the outlet gas, which can condensate and clog the pipes. Previous studies have highlighted the fact that the tar elimination via catalytic reforming seem to be the more practical and economical solution. Reforming catalysts present the following properties : a tailored mesoporous texture for the support and the high dispersion of active sites like metallic nanoparticles (Ni, Pd, Fe,…) [1]. In this work, Ni based alumina catalysts and doped with a second metal (Co, Cu, Fe, Mn, Mo) are synthesized by an aqueous sol-gel process. [less ▲]

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See detailEpidemiology of Prolactinomas
Beckers, Albert ULiege

Scientific conference (2017, September 07)

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See detailEffect of upgrading concrete strength class on fire performance of reinforced concrete columns
Gernay, Thomas ULiege; Peric, Vlado; Mihaylov, Boyan ULiege et al

in Gillie, Martin; Wang, Yong (Eds.) Proceedings of ASFE 2017 Conference (2017, September 07)

High strength concrete (HSC) provides several advantages over normal strength concrete (NSC) and is being used in multi-story buildings for reducing the dimensions of the columns sections and increasing ... [more ▼]

High strength concrete (HSC) provides several advantages over normal strength concrete (NSC) and is being used in multi-story buildings for reducing the dimensions of the columns sections and increasing the net marketable area. However, upgrading of concrete strength class in a building may affect the fire performance, due to higher rates of strength loss with temperature and higher susceptibility to spalling of HSC compared with NSC. Reduction of columns sections also leads to increased member slenderness and faster temperature increase in the section core. These detrimental effects are well known, but their impact on fire performance of structures has not been established in terms of comparative advantage between NSC and HSC. In other words, it is not clear whether the consideration of fire resistance limits the opportunities for use of HSC for reducing the dimensions of columns sections in multi-story buildings. This research aims to address this question by comparing the fire behaviour of reinforced concrete columns made of NSC and HSC using nonlinear finite element modelling. The evolution of load bearing capacity of the columns is established as a function of the fire exposure duration. A 15-story car park structure is adopted as a case study with alternative designs for the columns based on strength classes ranging from C30 to C90. Results show that, although the replacement of NSC by HSC accelerates the reduction rate of columns capacity under fire, the columns generally have significant reserves in resistance leading to sufficient fire resistance. This study gives an insight into the impact of replacing stocky sections in NSC by more slender sections in HSC on fire resistance rating for multi-story structures. [less ▲]

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