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See detailLaser cooling of iron atoms
Huet, Nicolas ULg

Doctoral thesis (2015)

The work presented in this thesis is dedicated to the development and implementation of a cold atom experiment which handles an atomic species that has not been cooled down so far: iron. The experiment ... [more ▼]

The work presented in this thesis is dedicated to the development and implementation of a cold atom experiment which handles an atomic species that has not been cooled down so far: iron. The experiment requires the use of two UV laser radiations (at 372 and 358 nm) that are frequency stabilized by means of saturation spectroscopy, an iron atomic beam, and a vacuum system, which we contributed to implement and characterize. In addition to this development, several spectroscopic studies were carried out in this thesis. By means of saturation spectroscopy, the hyperfine structure of the molecular-iodine R(90)3-10 transition at 716 nm was first studied following its involvement in the frequency stabilization of the 358-nm radiation. A spectroscopic study of the 358-nm Fe I cooling transition, which was totally unknown prior to this thesis, was also conducted using laser-induced fluorescence spectroscopy. With the same technique, a high accuracy measurement of the iron 358-nm transition frequency with respect to the molecular-iodine R(90)3-10 transition was performed. For this measurement, we implemented a particular configuration which allowed for the minimising of an important systematic error. The first laser cooling of iron is also reported. For this purpose, the Zeeman slowing technique was implemented following a particular two-laser scheme. To our knowledge, this Zeeman slower is the first of this kind. Furthermore, the complete characterization of the cold iron atomic beam produced at the output of the Zeeman slower was done, which allowed for an optimized loading of the magneto-optical trap. Finally, the creation of a cold cloud of iron atoms demonstrated the Zeeman slower ability to properly load an iron magneto-optical trap. [less ▲]

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See detailAménités résidentielles et périurbanisation : enseignements de l'approche hédonique appliquée au marché foncier liégeois
Maldague, Hubert ULg; Halleux, Jean-Marie ULg

Conference (2015, December 10)

La présente communication est une réflexion sur la périurbanisation observée dans le bassin d'emploi de Liège sur base des résultats d'un mémoire de master en sciences géographiques (Maldague, 2014). Les ... [more ▼]

La présente communication est une réflexion sur la périurbanisation observée dans le bassin d'emploi de Liège sur base des résultats d'un mémoire de master en sciences géographiques (Maldague, 2014). Les modèles développés montrent en effet une forte opposition entre la vieille agglomération industrielle délaissée et les périphéries plus vertes et agréables. Cette dualité contribue au maintien de l'importe périurbanisation que connait la région de Liège depuis plusieurs décennies. [less ▲]

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See detailPrelimary report of the Programme Committee of World Conference of Humanities
Winand, Jean ULg

Conference (2015, December 09)

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See detailLa traduction de l’humour dans la poésie orale peule du Cameroun
Oumarou Mal Mazou, Rachid ULg

Poster (2015, December 09)

Le poster présente le projet de thèse en cours de finalisation à l'Université de Liège

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See detailProlonger la vie, "Refaire" la société ?
Absil, Gaëtan ULg

Conference given outside the academic context (2015)

Nous vivons de plus en plus vieux. Cette conférence interroge cette vérité sous l’angle de l’anthropologie. Ainsi si nous vivons de plus en vieux, nous devons nous interroger sur le sens de ce « nous » et ... [more ▼]

Nous vivons de plus en plus vieux. Cette conférence interroge cette vérité sous l’angle de l’anthropologie. Ainsi si nous vivons de plus en vieux, nous devons nous interroger sur le sens de ce « nous » et sur le sens de « vieux ». Qui seront les personnes, les groupes sociaux qui vivront les plus vieux ? Que pourrait signifier la vieillesse ? Au coeur de ces questions se situent différents enjeux qui structureront la conférence. Une première série d’enjeux concerne la manière dont l’allongement de la vie, et peut-être l’immortalité promise par le transhumanisme, pourraient inciter à refaire, dans le sens de changer, la société et donc les rapports sociaux. Une deuxième série d’enjeux, connexes aux premiers, interroge les limites de l’allongement de vie sous l’angle d’un « refaire » qui pourrait être un jeu de dupe. [less ▲]

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See detailSexual attraction in lady beetles: fundamentals and applications
Fassotte, Bérénice ULg

Scientific conference (2015, December 09)

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See detailRègles pénitentiaires européennes et position juridique du détenu en Belgique
Seron, Vincent ULg

Conference given outside the academic context (2015)

Detailed reference viewed: 17 (3 ULg)
See detailLa voix narrative comme problème de traduction
Viehöver, Vera ULg

Scientific conference (2015, December 09)

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See detailA la recherche des traducteurs. Ou comment faire parler les archives.
Letawe, Céline ULg

Conference (2015, December 09)

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See detailModelling of cooling and heat treatment of bimetallic rolling mill rolls
Neira Torres, Ingrid ULg

Doctoral thesis (2015)

This work is focused on the modelling of post casting cooling and heat treatment stages, using a coupled thermo-mechanical metallurgical model in order to understand the behavior of bimetallic rolling ... [more ▼]

This work is focused on the modelling of post casting cooling and heat treatment stages, using a coupled thermo-mechanical metallurgical model in order to understand the behavior of bimetallic rolling mill rolls. The case of interest is a bimetallic rolling mill roll which materials and geometry present a risk of failure in industrial manufacturing. The analysis of residual stress fields together with a rough damage approach allows the understanding of the failure event and predicting trends when industrial conditions are modified. Performed finite element modelling requires a complete set of materials parameters. Experimental and numerical methods are applied in order to obtain thermophysical, mechanical, metallurgical and coupled parameters. Sensitivity analysis is performed in order to evaluate the effect of numerical predictions to different input data, modeling eventual modifications of materials or geometries. Finally, conclusions and perspectives obtained from this research allow establishing some weakness of the implemented model, enhancing the importance of considering more advanced damage models. In addition, it is settled that the material characterization must be improved by considering materials pollution and complexity. However the work provides a convincing explanation of the observed phenomena of ruptures. [less ▲]

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See detailFrom sample hunt to sequence processing, the journey of a biologist
André, Adrien ULg; Millien, Virginie; Michaux, Johan ULg

Conference (2015, December 08)

Metabarcoding studies are becoming more and more popular with a field of applications constantly increasing. However, the methods used are sometimes complex and might remain “obscure” for most of us. The ... [more ▼]

Metabarcoding studies are becoming more and more popular with a field of applications constantly increasing. However, the methods used are sometimes complex and might remain “obscure” for most of us. The objective of this presentation is therefore to familiarize people with this field of research by giving an overview of the different steps permitting the achievement of metabarcoding studies. Field work, lab work and bioinformatics will be subsequently detailed and accessibly explained. [less ▲]

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See detailSynthesis and characterization of novel donor-acceptor isoindigo-based conjugated copolymers and small molecules and their integration in organic photovoltaics
Tomassetti, Mirco ULg

Doctoral thesis (2015)

The conversion of solar energy into electricity is an environmentally friendly, safe and low- cost way of renewable energy production. Among the different photovoltaic technologies, organic photovoltaics ... [more ▼]

The conversion of solar energy into electricity is an environmentally friendly, safe and low- cost way of renewable energy production. Among the different photovoltaic technologies, organic photovoltaics (OPV) have particular assets in terms of aesthetics, flexibility and low-cost large area coverage. Nevertheless, the moderate OPV efficiencies (˞11%) and lack of durability (< 10 years) strongly limit their large-scale exploitation in particular consumer goods. The main goal of this thesis is to deal with these two drawbacks by designing novel conjugated polymers and small molecules with broad absorption in the visible range (i.e. low band gap), and by setting up strategies to improve the (thermal) stability of the photovoltaic cells. To this extent, novel push-pull type organic semiconducting materials have been synthesized, with different architectures and composed of electron-poor isoindigo building blocks alternating with electron-rich moieties, presenting a favorable spectral overlap with the solar emission. The optical properties of the novel materials were generally investigated by UV-visible absorption spectroscopy, while cyclic voltammetry was implemented to estimate the frontier orbital (HOMO/LUMO) energy levels. Relationships between the chemical nature and architecture of the push-pull systems and their absorption spectra and HOMO-LUMO energy levels have been pursued. Finally, the photovoltaic performances of the new materials have been evaluated in conventional bulk heterojunction organic solar cells using methanofullerene acceptor materials. Correlations between the molecular and photovoltaic parameters have been established. Ultimately, cross-linkable diblock copolymers based on poly(3-hexylthiophene) (P3HT) have been synthesized to improve the long-term stability of P3HT/PC61BM photovoltaic cells. Bulk heterojunction polymer solar cells have been prepared and their stability has been evaluated by accelerated ageing experiments and compared with standard P3HT-based devices. [less ▲]

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See detailImpact of cyclonic and anticyclonic activity on Greenland ice sheet surface mass balance variation during 1980–2013
Chen, L.; Fettweis, Xavier ULg; Knudsen, E. et al

in International Journal of Climatology (2015)

The Greenland ice sheet (GrIS) has experienced dramatic ice loss during recent decades, but the drivers of the surface mass balance (SMB) variation remain unclear. From a dynamical perspective ... [more ▼]

The Greenland ice sheet (GrIS) has experienced dramatic ice loss during recent decades, but the drivers of the surface mass balance (SMB) variation remain unclear. From a dynamical perspective, extratropical cyclones and anticyclones are the major systems influencing Greenland weather conditions. Seasonal cyclonic and anticyclonic activities have been quantified for the area of 50°–90°N, 80°W–10°E during 1980–2013. Based on a singular value decomposition (SVD) analysis, we investigated the role of synoptic scale cyclonic and anticyclonic activities in determining snow accumulation (SA) and surface air temperature (SAT). Thus, the SA-driven and melt-driven SMB variability has been determined. SA-related synoptic patterns identified from the leading and the second SVD modes explain up to 80% of the inter-annual SMB variance, especially in southern and northwestern Greenland, where we found the largest and second largest amount of annual SA. SAT-related patterns account for up to 80% of the inter-annual SMB variation along the west and northwest coast of Greenland, where significant surface mass loss has been observed over the last decades. It should be noted that the negative phase of the SA-related pattern derived from the first SVD mode in June-July-August and the positive phase of the SAT-related (anti)cyclonic patterns have occurred more frequently since 2005, meaning that the phase change of these patterns has made a major contribution to the accelerated GrIS surface ice loss during recent years. [less ▲]

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See detailIntegration Analysis of Three Omics Data Using Penalized Regression Methods: An Application to Bladder Cancer
Pineda San Juan, Silvia ULg; Real, Francisco X; Kogevinas, Manolis et al

in PLoS Genetics (2015)

Detailed reference viewed: 33 (5 ULg)