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See detailElemental 2D imaging of paintings with a mobile EDXRF system
Hocquet, François-Philippe ULiege; Calvo Del Castillo, Helena ULiege; Cervera Xicotencatl, Ariadna ULiege et al

in Analytical and Bioanalytical Chemistry (2011), 399(9), 3109-3116

Imaging techniques are now used commonly and intensively in cultural heritage object analysis. Nowadays, many different techniques in nature as well as many applications exist, where they can be applied ... [more ▼]

Imaging techniques are now used commonly and intensively in cultural heritage object analysis. Nowadays, many different techniques in nature as well as many applications exist, where they can be applied. X-ray radiography and infrared reflectography as well as UV photography are some of the most applied techniques. The study of works of art usually requires these techniques to be non-invasive. Furthermore, they are frequently required to perform in situ analysis. A few years ago, our laboratory developed a mobile energy-dispersive X-ray fluorescence and UV-vis-NIR coupled spectrometer, especially designed for fieldwork studies, where all three techniques can be applied strictly at the same site of analysis. Recent developments on a new positioning system have now allowed us to perform 2D elemental mappings with our equipment, which is especially well adapted to painting analysis. The system control is carried out entirely through a laptop computer running a dedicated homemade software. The positioning is achieved by means of a CCD camera embedded in the system and controlled via a Wi-Fi connection through the computer. The data acquisition system, which is made through a homemade multichannel pulse height analyzer, being also managed via the software mentioned above, goes through an Ethernet connection. We will present here the new developments of the system and an example of in situ 2D elemental mapping applied on an anonymous oil painting on wood panel. The discovery of a hidden painting under this oil painting makes it a good choice for a first example of 2D large scan with a mobile instrument. © Springer-Verlag 2010. [less ▲]

Detailed reference viewed: 155 (46 ULiège)
See detailElemental and Isotopic Abundances in Metal-Poor Stars
Magain, Pierre ULiege

in Walsh, J. R.; Danziger, I. J. (Eds.) Science with the VLT, Proceedings of the ESO Workshop held at Garching, Germany, 28 June - 1 July 1994 (1995)

Detailed reference viewed: 6 (0 ULiège)
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See detailElemental composition of soils and sediments by using portable X-ray fluorescence (pXRF) spectroscopy: a preliminary study
Alberti, Roberto; Falsone, Gloria; Gironda, M. et al

Poster (2017, December)

Portable X-ray fluorescence spectrometry (pXRF) provides rapid and low-cost analysis in laboratory and field conditions for a wide range of environmental applications. Its successful application in soils ... [more ▼]

Portable X-ray fluorescence spectrometry (pXRF) provides rapid and low-cost analysis in laboratory and field conditions for a wide range of environmental applications. Its successful application in soils requires a good instrument calibration and the possibility to implement custom calibrations and methods using known samples as well as reference materials. In the present study two set of samples, one from pedogenized sediments of a basin in Marradi (Italy; n=13) and the other from agricultural land in Meuse valley (Belgium; n=10), were analyzed by using a portable X-ray fluorescence (pXRF TRACER 5i made by Bruker) to detect and quantify the element species (Al, Si, Ca, Fe, Mg, K, Mn, P, S, Ba, Cd, Co, Cr, Cu, Mo, Pb, Sb, Sn, Sr and Zn). Element concentrations results were compared with analytical results from aqua regia extractions (AQ) followed by ICP-OES analysis. The aim of this work was to verify and find the best instrument setup for the specific matrix, elements and their concentration range with the purpose of using the pXRF technique directly insitu for the screening of sites potentially polluted. A standard factory calibration for soil applications was used for samples from Meuse valley, while a custom calibration for P, S, Ca and Fe quantification with the coefficient correction method was developed and used for pedogenized sediments from Marradi, as well as for Cu and Cr quantification in both sites. Comparing portable XRF and AQ results, elements could be grouped in three classes: 1) elements where the content determined by both methods is not correlated (p>0.05; Al, Si, and K); 2) elements strongly correlated (0.84<r<0.99, p<0.001; P, S, Mn, Fe, Ca, Cu, Cr, Zn and Pb); 3) elements with a weaker correlation (0.67<r<0.78, p<0.01; Mg and Sr). A further class of elements (Co, Mo, Cd, Sn, Sb, and Ba) was not evaluable because their concentration was below the detection limit of the pXRF. The measured concentrations and the relationship between pXRF and AQ were obviously affected by the elements form in the soils. The value of macroelements commonly related to the silicate phase measured by portable XRF is higher than that determined by AQ, which does not allow the destruction of Si-O and Al-O bounds (explaining the uncorrelation in the class 1 elements). The elements related to the organic matter (P and S, r2>0.60), carbonates (Ca, r2>0.55) and oxy(hydr)oxides (Fe and Mn) have instead comparable concentrations between pXRF and AQ. Preliminary results showed that portable XRF can quickly provide data for some elucidations of important pedogenic processes involving many elements (class 2) in the studied soils. Alternative methods offer results after expensive and time-consuming analytical procedures. Moreover for environmental and human health purposes, the pXRF should be a valid tool for a rapid screening of heavy metals, such as Cu, Cr, Zn and Pb. A larger set of soil samples and further custom calibration will be tested. [less ▲]

Detailed reference viewed: 41 (0 ULiège)
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See detailThe elementary reactions of energy selected 1,1-Difluoroethene ions.
Güthe, F.; Weitzel, K.-M.; Baumgärtel, H. et al

Book published by Berliner Elektronen Speicherring für Synchrotron Strahlung m.b.H (1996)

The dissociative photoionization dynamics of 1,1-difluoroethene has been investigated by TPEPICO using synchrotron radiation. The breakdown diagram has been build. The attention has been focussed on C2HF ... [more ▼]

The dissociative photoionization dynamics of 1,1-difluoroethene has been investigated by TPEPICO using synchrotron radiation. The breakdown diagram has been build. The attention has been focussed on C2HF+ (HF-loss) channel. [less ▲]

Detailed reference viewed: 154 (0 ULiège)
Peer Reviewed
See detailAn elementary shortest path problem with variable service start time
Kucukaydin, Hande ULiege; Arda, Yasemin ULiege; Crama, Yves ULiege

Conference (2013, May 02)

We consider an elementary shortest path problem with resource constraints (ESPPRC), where a capacitated single vehicle serves a set of delivery and backhaul customers with a revenue and a time window. On ... [more ▼]

We consider an elementary shortest path problem with resource constraints (ESPPRC), where a capacitated single vehicle serves a set of delivery and backhaul customers with a revenue and a time window. On a given route, the vehicle can visit a backhaul customer only after all its delivery customers are visited, where a customer is either a delivery or a backhaul customer, but not both. Split deliveries and pick-ups are not allowed. In this problem, multiple trips are allowed so that the vehicle can be assigned to several routes. In addition, the vehicle can begin servicing the customers at any desired time and can be used for at most a fixed amount of time that depends on the shift duration of the assigned driver. Distance and time based variable costs are incurred by serving the customers. In other words, the total cost depends on the total distance traveled and the total amount of time that the vehicle spends by performing the assigned multiple trips. On the other hand, serving a customer yields also a revenue. Therefore, the aim is to determine the optimal service start time of the vehicle from the depot along with the trips to be performed in order to minimize the routing costs minus the collected revenues. Such a problem can be faced as the pricing subproblem in branch-and-price algorithms for vehicle routing problems with additional constraints, where the revenues are equivalent to the dual prizes of the visited vertices. In general, ESPPRC can be solved to optimality by using a dynamic programming algorithm. However, since the vehicle can start the service at any point in time and is paid based on the total time during which it has been used, our ESPPRC has to take an infinite number of Pareto-optimal states into account. Therefore, we adapt the well-known dynamic programming algorithm according to this feature and develop piecewise linear time functions that represent total traveling and waiting time depending on a variable start time at the depot. Consequently, we propose appropriate dominance rules to discard feasible paths that cannot lead to the optimal solution. Finally, we present computational results. [less ▲]

Detailed reference viewed: 49 (1 ULiège)
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See detailElementi di docimologia : valutazione continua e esami
de Landsheere, Gilbert ULiege

Book published by La Nuova Italia Editrice (1973)

Il caso in cui ci si crede infallibili nei giudizi non è infrequente. L'occhio clinico, come il buon senso, sembra una merce di cui nessuno lamenta la mancanza. Nel campo della scuola: sia in occasione di ... [more ▼]

Il caso in cui ci si crede infallibili nei giudizi non è infrequente. L'occhio clinico, come il buon senso, sembra una merce di cui nessuno lamenta la mancanza. Nel campo della scuola: sia in occasione di un esame risolutivo, istantaneo, condotto una tantum e con eito inappellabile, sia, con maggiori giustificazioni, nel caso di scolari seguiti per intere annate scolastiche, magari per un intero corso di studi. Poi saltano fuori i ' freddi ' metodi statistici, e si scopre che per un'ovvia legge psicologica, della quale però tendiamo a non prendere coscienza, siamo portati - a parità di condizioni - ad abbassare il voto di uno scolaro ritenuto mediocre e a tenere alto quello del figlio del professionista di grido, fino ad attribuire l'insufficienza al compito eseguito di nascosto da un docente universitario. La docimologia non si presenta quindi solo come la scienza della giustizia distributiva ma anche come un detector delle nostre debolezze, dei nostri idola theatri. Quanto il dominio critico di queste manchevolezze o limiti oggettivi sia necessario lo si può capire solo pensando all'influenza che valutazioni su scala nazionale come esami o concorsi possono avere sul destino di migliaia di candidati. [less ▲]

Detailed reference viewed: 40 (7 ULiège)
See detailElementi di docimologia : valutazione continua ed esami
de Landsheere, Gilbert ULiege

Book published by La Nuova Italia (1974)

Detailed reference viewed: 89 (4 ULiège)
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See detailÉlements affectant la précision du GPS RTK
Wautelet, Gilles ULiege

Conference given outside the academic context (2013)

Detailed reference viewed: 66 (4 ULiège)
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See detailEléments bibliographiques pour une histoire géologique de la notion de race
Gérard, Marie ULiege

Conference (2012, October 30)

La notion de race est un produit historique dont la définition actuelle est le résultat de déplacements successifs des significations. Cette évolution est reliée à des évolutions des connaissances mais ... [more ▼]

La notion de race est un produit historique dont la définition actuelle est le résultat de déplacements successifs des significations. Cette évolution est reliée à des évolutions des connaissances mais aussi des usages et des dispositifs de mise en valeur et des modes d'organisation sociale de l'élevage. [less ▲]

Detailed reference viewed: 33 (3 ULiège)
See detailEléments d’actualité fiscale
Bourgeois, Marc ULiege

Conference given outside the academic context (2013)

Detailed reference viewed: 17 (5 ULiège)
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See detail« Elements d’actualité fiscale : Taxation des revenus mobiliers, nouvelles obligations de mention dans la déclaration et régularisation fiscale »
Bourgeois, Marc ULiege; Garroy, Sabine ULiege

in Fiscale Praktijkstudies (2013), 39

La contribution se subdivise en trois parties, chacune envisageant une question particulière. 1) Un premier chapitre a fait la synthèse et le point sur les évolutions du régime de taxation des revenus ... [more ▼]

La contribution se subdivise en trois parties, chacune envisageant une question particulière. 1) Un premier chapitre a fait la synthèse et le point sur les évolutions du régime de taxation des revenus mobiliers, depuis l’entrée en fonction du Gouvernement di Rupo. L’objet du propos est informatif et descriptif. 2) Dans un deuxième temps, nous avons analysé plus en détails le souci de transparence des patrimoines qui anime notre législateur, par le biais de l’introduction de nouvelles obligations de mention dans la déclaration annuelle à l’impôt des personnes physiques (assurances-vie individuelles auprès d’entreprises d’assurance établies à l’étranger ; existence d’une « construction juridique »), ou encore des efforts accomplis avec d’autres Etats membres au niveau de l’Union européenne. 3) Enfin, l’examen de la procédure de régularisation fiscale, telle que réformée par la loi du 11 juillet 2013 a fait l’objet du troisième chapitre. [less ▲]

Detailed reference viewed: 95 (23 ULiège)
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See detailEléments d'économie de la santé
Djenane, Majid; Robert, Jocelyne ULiege

Conference (2014, February 02)

Detailed reference viewed: 15 (5 ULiège)
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See detailEléments d'économie politique
De Laveleye, Émile ULiege

Book published by Hachette - Deuxième édition (1884)

Detailed reference viewed: 1 (0 ULiège)
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See detailEléments d'examens complémentaires en médecine sportive : illustrations
Frippiat, Thibault ULiege

Learning material (2011)

Quelques illustrations des atteintes fréquentes en médecine sportive, concernant l'endoscopie des voies respiratoires supérieurs (au repos et à l'effort), le test de fonction pulmonaire (IOS) et l ... [more ▼]

Quelques illustrations des atteintes fréquentes en médecine sportive, concernant l'endoscopie des voies respiratoires supérieurs (au repos et à l'effort), le test de fonction pulmonaire (IOS) et l'électrocardiogramme. [less ▲]

Detailed reference viewed: 51 (11 ULiège)
See detailEléments d'une nouvelle géographie industrielle de la Communauté Européenne
Merenne-Schoumaker, Bernadette ULiege

Book published by Cahier pédagogique du Ministère de l'Education nationale et de la Culture française (1981)

Folder organized around four themes: importance and evolution of industry, spatial distribution, new trends in localization and Europe facing international changes

Detailed reference viewed: 15 (0 ULiège)