Last 7 days     Results 1701-1720 of 70266.   81 82 83 84 85 86 87 88 89 90 91   Effects of High Solidification Rates on Segregations and Solid Phase Transformations in High Speed SteelsTchuindjang, Jérôme Tchoufack ; Sinnaeve, Mario; Lecomte-Beckers, Jacqueline in MATSUBARA, Yasuhiro; SASAGURI, Nobuya; YAMAMOTO, Kaoru (Eds.) ABRASION 2017 - The 6th International COnference on Abrasion Wear Resistant Alloyed White Cast Iron for Rolling and Pulverizing Mills (2017, August)High Speed Steels (HSS) represent high alloyed steels that belong to the complex Fe-Cr-C-X system whit X being a strong carbide forming element such as V, Nb, Mo or W. During the solidification of HSS ... [more ▼]High Speed Steels (HSS) represent high alloyed steels that belong to the complex Fe-Cr-C-X system whit X being a strong carbide forming element such as V, Nb, Mo or W. During the solidification of HSS, segregations corresponding to preferential distribution of elements can occur. Segregations are influenced both by the initial chemical composition and by the casting route, which is the case with conventional spin casting process. But the same phenomenon should also exist with the expanding additive manufacturing techniques that involved higher thermal gradients and higher cooling rates compared to classical processes. The solid phase transformations are controlled by the local concentrations of elements, especially the supersaturation which may exist in certain regions. That is the reason why the segregations inherited from the solidification of the HSS alloys lead to unexpected solid state phase transformations during the ongoing cooling stage. These phase transformations may occur either in the moderate temperature range or subsequently in the lower temperature range which is close to the ambient temperature, as for the martensitic transformation. In the present work a general review of the literature dealing with the fundamentals of solidification is reviewed aiming at justifying the need to search for tools that will be more adapted to simulate or study the microstructures obtained by manufacturing processes such as laser cladding, which refer to conditions far away from equilibrium. The new approach to understanding non-equilibrium structures also requires consideration of related studies with materials that are different from the HSS alloys, such as stainless steels, in order to take advantage of relevant analyzes that have already been achieved in other areas. The study is open, because the scope of the analyses is large and it can be extend to the phase transformations and also to the properties. Some relevant results obtained on two HSS processed by laser cladding are discussed related to the solidification mode and the solidification sequence. [less ▲]Detailed reference viewed: 17 (1 ULiège) La difficile jointure des directives EU anti-BEPS et des traités fiscauxDocclo, Caroline in Fiscologue International = Fiscoloog internationaal (2017)Detailed reference viewed: 41 (5 ULiège) Thermoelectric properties of heavily-doped Fe2YZ full-Heusler compoundsLemal, Sébastien ; Ricci, Fabio ; Verstraete, Matthieu et alPoster (2017, July 31)Fe2YZ full-Heusler compounds were recently predicted to exhibit very large thermoelectric power factors [Phys. Rev. Lett. 114, 136601 (2015)]. Combining first-principles density functional theory ... [more ▼]Fe2YZ full-Heusler compounds were recently predicted to exhibit very large thermoelectric power factors [Phys. Rev. Lett. 114, 136601 (2015)]. Combining first-principles density functional theory calculations within a hybrid functional approach and Boltzmann semi-classical transport theory, we investigate the limits of the rigid band doping approximation, and the properties of heavily n-type doped full-Heusler Fe2YZ1-xAx compounds. Using a supercell approach and including explicit dopant impurities, we recover in some cases giant thermoelectric power factors, as previously predicted within the rigid band approximation. In others the effect on the electronic structure is very different from rigid shifts. Interestingly, we find that some systems present a magnetic instability consistent with the Stoner model, and evolve towards a ferromagnetic half-metallic ground state, with a strongly modified power factor. Our results show the promise of the heavily-doped phases of the studied Fe2YZ1-xAx compounds for Seebeck and spin-dependent Seebeck applications. [less ▲]Detailed reference viewed: 90 (7 ULiège) High School Sport in Belgium (Wallonia)Cloes, Marc Conference (2017, July 31)In Belgium, since 1969, sport is a competence under the control of public authorities defined according to the linguistic regime. As in most Western European countries, sport has been compartmentalised by ... [more ▼]In Belgium, since 1969, sport is a competence under the control of public authorities defined according to the linguistic regime. As in most Western European countries, sport has been compartmentalised by giving rise to three main types of practice: "professional", "traditional" and "alternative" sports (Diegel, 1995). Clubs linked to sports federations constitute the local setting up of the sports organization, which is largely a majority (Zintz, 2014). Other operators from the public domain and the private sphere coexist (Cloes, 2012). In the school environment, sport can be found in three contexts: within the compulsory curriculum (physical education), integrated to extracurricular activities (activities organized during recess or free periods), and peripheral activities (use of school sports facilities by organizers who are not belonging to the school actors). If inter-school competitions are organized by several school sports federations (depending to the educational network), they are far from reaching the interest and involvement reached by the competitions managed by the traditional sports federations. So there is hardly any systematic sports training in French-speaking Belgian schools. Some PE teachers propose voluntary training sessions but there are less and less connections between their actions and sport clubs. On the other hand, young sportsmen appointed by the Minister of Sports have a special status enabling them to benefit facilities to pursue their double career. They are sometimes gathered in special organizations - sport-studies or development centers - which have been the subject of several studies (Cloes et al., 2002, Lacrosse et al., 2014, Theunissen et al., 2016) but PE teachers are very few involved in these development opportunities. In many situations of partnership between the school and sports structures, their role is often limited to a simple accompanying action (sports days, projects "My club-My school." Cloes (2017) insisted however on the need to make them a priority in the coordination of the preparation of physically educated citizens. References Cloes, M. (2012). La Wallonie en mouvement : vers une culture sportive et de l’activité physique ? In, M. Germain et R. Robaye (Eds.), L'état de la Wallonie. Portrait d'un pays et de ses habitants – 2011. (pp. 70-80). Namur : Les éditions namuroises. Available on Internet : http://hdl.handle.net/2268/117294 Cloes, M. (2017). Preparing physically educated citizens in physical education. Expectations and practices. Retos, 31, 245-251. Available on Internet : http://recyt.fecyt.es/index.php/retos/article/view/53497/32304 Cloes, M., Schelings, V., Ledent, M, & Piéron, M. (2002). Sport-études : comparaison des caractéristiques motivationnelles et des relations sociales des élèves sportifs et de leurs condisciples. eJRIEPS (e Journal de la Recherche sur l'Intervention en Éducation Physique et Sport), 1, 57-72. Available on Internet: http://hdl.handle.net/2268/10187 Diegel, H. (1995). Sport in changing society – Sociological essays. Schorndorf: Verlag Karl Haufmann. Lacrosse, Z., Martin, V., & Cloes, M. (2014, July). Analyse qualitative du fonctionnement du centre de formation d’une fédération sportive. Paper presented at the 8ème biennale de l’ARIS ‘Temps, temporalités et intervention en EPS et en sport’, Genève, Suisse. Available on Internet: http://hdl.handle.net/2268/170020 Theunissen, C., Meys, G., & Cloes, M. (2016). Encadrement du staff autour du double projet des sportifs dans un centre de formation en handball. Revue de l’Éducation physique, 56, 1/2, 20. Disponible sur Internet: http://yessport.be/educationphysique/file/REVUE_1_ET_2_2016_-2eme_COLLOQUE_GUY_NAMUROIS.pdf ou http://orbi.ulg.ac.be/handle/2268/199016 Zintz, T. (2014). Module 3 - Le paysage sportif : du pratiquant aux fédérations. Thématique 1 - Cadre institutionnel et législatif. Cours généraux de la formation ‘Moniteur Sportif Initiateur’. Brussels, Belgium : Administration des sports, Fédération Wallonie-Bruxelles. Internet : http://www.sport.cfwb.be/index.php?id=7370 [less ▲]Detailed reference viewed: 43 (4 ULiège) Dynamicized semantic maps of content words. Comparing long-term lexical changes in Ancient Egyptian and GreekGeorgakopoulos, Athanasios ; Polis, Stéphane Conference (2017, July 31)This paper aims at demonstrating how information on the paths of semantic extensions undergone by content words may be incorporated into semantic maps. For this purpose, particular changes that affected ... [more ▼]This paper aims at demonstrating how information on the paths of semantic extensions undergone by content words may be incorporated into semantic maps. For this purpose, particular changes that affected the meanings of words in the course of the Ancient Egyptian and of the Ancient Greek language history are investigated. [less ▲]Detailed reference viewed: 63 (4 ULiège) Legal, official, academic and "trading" norms in higher DRC's educationPoncelet, Marc Conference (2017, July 31)Rule of legal, official, practical norms in DRC universityDetailed reference viewed: 17 (0 ULiège) Light exposure via head-mounted devices suppresses melatonin and improves vigilant attention without affecting cortisol and comfortSchmidt, Christina ; Xhrouet, Marine ; Hamacher, Manon et alPoster (2017, July 30)Detailed reference viewed: 25 (2 ULiège) Cation Distribution Dependent Magnetic Properties in CoCr 2-x Fe x O 4 (x= 0.1 to 0.5): EXAFS, Mӧssbauer and Magnetic MeasurementsKumar, Durgesh; Banerjee, Alok; Mahmoud, Abdelfattah et alin Dalton Transactions (2017), 46In this report, we have examined the evolution of the structure and rich magnetic transitions such as a paramagnetic to ferrimagnetic phase transition at the Curie temperature (TC), spiral ordering ... [more ▼]In this report, we have examined the evolution of the structure and rich magnetic transitions such as a paramagnetic to ferrimagnetic phase transition at the Curie temperature (TC), spiral ordering temperature (TS) and lock-in temperature (TL) observed in the CoCr2O4 spinel multiferroic after substituting Fe. The crystal structure, microstructure and cation distribution among the tetrahedral (A) and octahedral (B) sites in the spinel lattice are characterised by X-ray diffraction, transmission electron microscopy, Extended X-ray Absorption Fine Structure (EXAFS) and Mössbauer spectroscopy. Due to the same radial distances of the first coordination shell in both tetrahedral and octahedral environments observed in EXAFS spectra, the position of the second coordination shell specifies the preference of more Fe ions towards the A site at x = 0.1. At x = 0.5, more Fe ions favour the B site. The cation distribution quantitatively obtained from the Mössbauer spectral analysis shows that while 60% of Fe ions occupy the A site in x = 0.1, 40% occupy it in x = 0.5. Surprisingly at x = 0.3, Fe ions are distributed equally among the A and B sites. dc magnetization reveals an increase in TC from 102 K to 200 K and in TS from 26 to 40 K with an increase in Fe concentration, indicating an enhancement in A–B exchange interaction at the expense of B–B. No report has until now demonstrated such an enhancement in TS either in pure or in doped CoCr2O4. Furthermore, frequency-dependent ac susceptibility (χ) data fitted with different phenomenological models such as the Néel–Arrhenius, Vogel–Fulcher and power law confirm a spin-glass and/or cluster-glass behaviour in nanoparticles of CoCr2−xFexO4. [less ▲]Detailed reference viewed: 15 (3 ULiège) Écrire de “Guiron” en Flandre à la fin du Moyen ÂgeVeneziale, Marco Conference (2017, July 28)Detailed reference viewed: 16 (0 ULiège) Le maraîchage périurbain à Libreville et Owendo (Gabon) : pratiques culturales et durabilitéBayendi-Loudit, Sandrine ; Ndoutoume Ndong, Auguste; Francis, Frédéric in Cahiers Agricultures (2017)In Gabon, peri-urban gardening is an opportunity to provide vegetables to the main cities, such as Libreville and Owendo. Following a survey conducted in three market gardening areas, an inventory was ... [more ▼]In Gabon, peri-urban gardening is an opportunity to provide vegetables to the main cities, such as Libreville and Owendo. Following a survey conducted in three market gardening areas, an inventory was conducted on the socio-economic characteristics, the diversity of crops, and pesticide uses. The cropped areas range from 0.08 ha to 0.4 ha per farmer, according to the site. National operators represent 51%, while people from Burkina Faso manage 40% of vegetable production. The most cultivated species throughout the year are amaranth (Amaranthus hybridus L.), lettuce (Lactuca sativa L.), Guinea sorrel (Hibiscus sabdariffa L.) and black nightshade (Solanum nigrum L.). The most important pests are Aphididae and some beetles. The most commonly used plant protection products are insecticides, mainly conventional neurotoxic. Best crop monitoring, pest control including pesticide application reduction, and the possibility to offer microcredit systems to small producers would help increasing peri-urban healthy vegetable production and increase local food autonomy [less ▲]Detailed reference viewed: 39 (10 ULiège) El impacto del fin del “giro al la izquierda” sobre las relaciones entre China y América LatinaWintgens, Sophie Conference (2017, July 28)La llegada de China en América Latina a finales de los años 2000 se ha presentado como una nueva opción en el contexto histórico de un “movimiento pendular” que siempre ha visto los países latino ... [more ▼]La llegada de China en América Latina a finales de los años 2000 se ha presentado como una nueva opción en el contexto histórico de un “movimiento pendular” que siempre ha visto los países latino-americanos girar principalmente en torno a Europa y sus antiguas potencias coloniales o en torno a los Estados Unidos. En el marco de esa dinámica del “triángulo Atlántico” en la que se encuentra encerrada América Latina, China ha también beneficiado de un entorno regional propicio como consecuencia de factores tanto estructurales (las debilidades del regionalismo latinoamericano), como coyunturales (la escalada de la “nueva” izquierda sudamericana). El inicio de la década de 2010, sin embargo, parece marcar el final del “giro à la izquierda” y los límites del modelo de desarrollo extractivo adoptado por la mayoría de los gobiernos progresistas latino-americanos. Al mismo tiempo, las autoridades chinas han también iniciado un cambio de modelo de desarrollo económico con el undécimo Plan Quinquenal (2006-2010) para que sea más autocentrado y basado en la producción de productos de alta calidad. Basándose en estas observaciones, este ponencia interroga el impacto de este contexto sobre las relaciones entre China y América Latina. [less ▲]Detailed reference viewed: 43 (1 ULiège) Spray-drying as a tool to disperse conductive carbon inside Na2FePO4F particles by addition of carbon black or carbon nanotubes to the precursor solutionMahmoud, Abdelfattah ; Caes, Sebastien; Brisbois, Magali et alin Journal of Solid State Electrochemistry (2017)In this work, Na2FePO4F-carbon composite powders were prepared by spray-drying a solution of inorganic precursors with 10 and 20 wt% added carbon black (CB) or carbon nanotubes (CNTs). In order to compare ... [more ▼]In this work, Na2FePO4F-carbon composite powders were prepared by spray-drying a solution of inorganic precursors with 10 and 20 wt% added carbon black (CB) or carbon nanotubes (CNTs). In order to compare the effect of CB and CNTwhen added to the precursor solutions, the structural, electrochemical, and morphological properties of the synthesized Na2FePO4F-xCB and Na2FePO4F-xCNT samples were systematically investigated. In both cases, X-ray diffraction shows that calcination at 600 °C in argon leads to the formation of Na2FePO4F as the major inorganic phase. 57Fe Mössbauer spectroscopy was used as complementary technique to probe the oxidation states, local environment, and identify the composition of the iron-containing phases. The electrochemical performance is markedly better in the case of Na2FePO4F-CNT (20 wt%), with specific capacities of about 100 mAh/g (Na2FePO4F-CNT) at C/4 rate vs. 50 mAh/g for Na2FePO4F-CB (20 wt%). SEM characterization of Na2FePO4F-CB particles revealed different particle morphologies for the Na2FePO4F-CNT and Na2FePO4F-CB powders. The carbon-poor surface observed for Na2FePO4FCB could be due to a slow diffusion of carbon in the droplets during drying. On the contrary, Na2FePO4F-CNT shows a better CNT dispersion inside and at the surface of the NFPF particles that improves the electrochemical performance. [less ▲]Detailed reference viewed: 33 (12 ULiège) Synthesis and complexation of superbulky imidazolium-2-dithiocarboxylate ligandsBeltran Alvarez, Tomás Francisco ; Zaragoza, Guillermo; Delaude, Lionel in Dalton Transactions (Cambridge, England : 2003) (2017), 46(28), 9036-9048The superbulky N-heterocyclic carbenes (NHCs) 2,6-bis(diphenylmethyl)-4-methylimidazol-2-ylidene (IDip*Me) and its 4-methoxy analogue (IDip*OMe) reacted instantaneously with carbon disulfide to afford the ... [more ▼]The superbulky N-heterocyclic carbenes (NHCs) 2,6-bis(diphenylmethyl)-4-methylimidazol-2-ylidene (IDip*Me) and its 4-methoxy analogue (IDip*OMe) reacted instantaneously with carbon disulfide to afford the corresponding imidazolium-2-dithiocarboxylate zwitterions in high yields. These new dithiolate ligands were fully characterized and their coordination chemistry toward common Re(i) and Ru(ii) metal sources was thoroughly investigated. Neutral [ReBr(CO)3(S2C[middle dot]NHC)] chelates featured three facially-arranged carbonyl groups on a distorted octahedron, whereas cationic [RuCl(p-cymene)(S2C[middle dot]NHC)]PF6 complexes displayed a piano-stool geometry. The molecular structures of the six new compounds revealed that the NHC[middle dot]CS2 inner salts were highly flexible. Indeed, the torsion angle between their anionic and cationic moieties varied between ca. 63[degree] in the free ligands and 3[degree] in the ruthenium complexes. Concomitantly, the S-C-S bite angle underwent a contraction from 131[degree] to 110-113[degree] upon chelation. Computation of the %VBur parameter showed that the dithiocarboxylate unit of the NHC[middle dot]CS2 betaines chiefly determined the steric requirements of the imidazolium moieties, irrespective of the metal center involved in the complexation. The replacement of the p-methyl substituents of IDip*Me with p-methoxy groups in IDip*OMe did not significantly affect the ligand bulkiness. The more electron-donating methoxy group led, however, to small changes in various IR wavenumbers used to probe the electron donor properties of the carbene moiety. [less ▲]Detailed reference viewed: 20 (2 ULiège) Le projet « Pratiques et stratégies alimentaires dans l'Antiquité tardive »Marganne, Marie-Hélène Conference (2017, July 28)Detailed reference viewed: 30 (6 ULiège) Occupational social and mental stimulation and cognitive decline with advancing ageGrotz, Catherine ; Meillon, Céline; Amieva, Hélène et alin Age and Ageing (2017)Detailed reference viewed: 33 (1 ULiège) Is supercritical fluid chromatography hyphenated to massspectrometry suitable for the quality control of vitamin D3 oilyformulations?Andri, Bertyl ; Dispas, Amandine ; Klinkenberg, Régis et alin Journal of Chromatography. A (2017), 1515Nowadays, many efforts are devoted to improve analytical methods regarding efficiency, analysis timeand greenness. In this context, Supercritical Fluid Chromatography (SFC) is often regarded as a ... [more ▼]Nowadays, many efforts are devoted to improve analytical methods regarding efficiency, analysis timeand greenness. In this context, Supercritical Fluid Chromatography (SFC) is often regarded as a goodalternative over Normal Phase Liquid Chromatography (NPLC). Indeed, modern SFC separations arefast, efficient with suitable quantitative performances. Moreover, the hyphenation of SFC to mass spec-trometry (MS) provides additional gains in specificity and sensitivity. The present work aims at thedetermination of vitamin D3 by SFC-MS for routine Quality Control (QC) of medicines specifically. Basedon the chromatographic parameters previously defined in SFC-UV by Design of Experiments (DoE) andDesign Space methodology, the method was adapted to work under isopycnic conditions ensuring a base-line separation of the compounds. Afterwards, the response provided by the MS detector was optimizedby means of DoE methodology associated to desirability functions. Using these optimal MS parameters,quantitative performances of the SFC-MS method were challenged by means of total error approachmethod validation. The resulting accuracy profile demonstrated the full validity of the SFC-MS method. It was indeed possible to meet the specification established by the European Medicines Agency (EMA) (i.e. 95.0 − 105.0% of the API content) for a dosing range corresponding to at least 70.0-130.0% of theAPI content. These results highlight the possibility to use SFC-MS for the QC of medicine and obviouslysupport the switch to greener analytical methods. [less ▲]Detailed reference viewed: 23 (6 ULiège) The Prediction-Focused Approach: An opportunity for hydrogeophysical data integration and interpretation in the critical zoneHermans, Thomas ; Nguyen, Frédéric ; Klepikova, Maria et alPoster (2017, July 27)Two important challenges remain in hydrogeophysics: the inversion of geophysical data and their integration in quantitative subsurface models. Classical regularized inversion approaches suffer from ... [more ▼]Two important challenges remain in hydrogeophysics: the inversion of geophysical data and their integration in quantitative subsurface models. Classical regularized inversion approaches suffer from spatially varying resolution and yield geologically unrealistic solutions, making their utilization for model calibration less consistent. Advanced techniques such as coupled inversion allow for a direct integration of geophysical data; but, they are difficult to apply in complex cases and remain computationally demanding to estimate uncertainty. We investigated a prediction-focused approach (PFA) to directly estimate subsurface physical properties relevant in the critical zone from geophysical data, circumventing the need for classic inversions. In PFA, we seek a direct relationship between the data and the subsurface variables we want to predict (the forecast). This relationship is obtained through a prior set of subsurface models for which both data and forecast are computed. A direct relationship can often be derived through dimension reduction techniques (Figure 1). For hydrogeophysical inversion, the considered forecast variable is the subsurface variable, such as the salinity or saturation for example. An ensemble of possible solutions is generated, allowing uncertainty quantification. For data integration, the forecast variable is the prediction we want to make with our subsurface models, such as the concentration of contaminant in a drinking water production well. Geophysical and hydrological data are combined to derive a direct relationship between data and forecast. We illustrate the methodology to predict the energy recovered in an ATES system considering the uncertainty related to spatial heterogeneity. With a global sensitivity analysis, we identify sensitive parameters for heat storage prediction and validate the use of a short term heat tracing experiment to generate informative data. We illustrate how PFA can be used to successfully derive the distribution of temperature in the aquifer from ERT during the heat tracing experiment. Then, we successfully integrate the geophysical data to predict heat storage in the aquifer using PFA. The result is a full quantification of the posterior distribution of the prediction conditioned to observed data in a relatively limited time budget. [less ▲]Detailed reference viewed: 35 (7 ULiège) Deep imaging search for planets forming in the TW Hya protoplanetary disk with the Keck/NIRC2 vortex coronagraphRuane, G.; Mawet, D.; Kastner, J. et alin Astronomical Journal (The) (2017), 154Distinct gap features in the nearest protoplanetary disk, TW Hya (distance of 59.5$\pm$0.9 pc), may be signposts of ongoing planet formation. We performed long-exposure thermal infrared coronagraphic ... [more ▼]Distinct gap features in the nearest protoplanetary disk, TW Hya (distance of 59.5$\pm$0.9 pc), may be signposts of ongoing planet formation. We performed long-exposure thermal infrared coronagraphic imaging observations to search for accreting planets especially within dust gaps previously detected in scattered light and submm-wave thermal emission. Three nights of observations with the Keck/NIRC2 vortex coronagraph in $L^\prime$ (3.4-4.1$\mu$m) did not reveal any statistically significant point sources. We thereby set strict upper limits on the masses of non-accreting planets. In the four most prominent disk gaps at 24, 41, 47, and 88 au, we obtain upper mass limits of 1.6-2.3, 1.1-1.6, 1.1-1.5, and 1.0-1.2 Jupiter masses ($M_J$) assuming an age range of 7-10 Myr for TW Hya. These limits correspond to the contrast at 95\% completeness (true positive fraction of 0.95) with a 1\% chance of a false positive within $1^{\prime\prime}$ of the star. We also approximate an upper limit on the product of planet mass and planetary accretion rate of $M_p\dot{M}\lesssim10^{-8} M_J^2/yr$ implying that any putative $\sim0.1 M_J$ planet, which could be responsible for opening the 24 au gap, is presently accreting at rates insufficient to build up a Jupiter mass within TW Hya's pre-main sequence lifetime. [less ▲]Detailed reference viewed: 23 (5 ULiège) Real Options Valuation and Stress Test AnalysisLambert, Marie Conference (2017, July 27)Detailed reference viewed: 28 (5 ULiège) Mapping the dependency of crops on pollinators in BelgiumJacquemin, Floriane ; Violle, Cyrille; Rasmont, Pierre et alin One Ecosystem (2017)Detailed reference viewed: 27 (2 ULiège)