References of "Strivay, David"
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See detailAutomatic X-ray fluorescence scanning mobile system for 2D chemical analysis
Strivay, David ULg; Hocquet, François-Philippe; Dister, Hervé et al

Conference (2012, December)

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See detailX-ray methods
Calvo Del Castillo, Helena ULg; Strivay, David ULg

in Edwards, H; Vandenabeele, P (Eds.) Analytical Archaeometry: Selected Topics (2012)

Detailed reference viewed: 8 (2 ULg)
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See detailFusion alpha and proton diagnostics by thin layer activation
Chene, Grégoire ULg; Bonheure, George; Delhalle, René ULg et al

Conference (2012, September)

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See detailStudy of the alteration processes of Prussian blue in laboratory-prepared and genuine paint layers
Samain, Louise ULg; Sanyova, Jana; Strivay, David ULg

Conference (2012, July 09)

The necessity of understanding degradation and alteration processes in a painting's materials is well established for preservation and art history issues. The task is complex because of the highly ... [more ▼]

The necessity of understanding degradation and alteration processes in a painting's materials is well established for preservation and art history issues. The task is complex because of the highly heterogeneous character of an ancient paint layer. In this context we focus on a particular pigment, Prussian blue. Prussian blue is a hydrated ferric ferrocyanide complex, first synthesized in 1704 in Berlin. It has been widely used by artists until the 1970s. However, the permanence of Prussian blue had already been questioned by the mid-eighteenth century, because it exhibits a tendency to fade in light and to turn green. To date, little attention has been devoted to the understanding of the degradation processes of Prussian blue in paint layers. We induced discoloration upon light exposure in commercial and laboratory-synthesized Prussian blue watercolor and oil paint layers by accelerated ageing. Pure Prussian blue painted in a dark shade appears to be extremely light fast but fades when either painted in a lighter shade or mixed with white pigments. We analyzed the paint layers by various techniques, i.e., UV-visible, Fourier transform infrared, Raman, Mössbauer and X-ray absorption spectroscopy. We attributed the fading of Prussian blue to a reduction of the iron(III) ions at the surface of the paint layers. We also observed a partial oxidation of Prussian in the entire paint layer. Finally we confirmed these results by analyzing works of art containing Prussian blue, i.e., a polychrome sculpture, wallpapers and mural decoration sample. [less ▲]

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See detailCrystal Structure and Local Disorder in Modern and Ancient Prussian Blue Pigments
Samain, Louise ULg; Martinetto, Pauline; Bordet, Pierre et al

Poster (2012, June 06)

The necessity of understanding degradation and alteration processes in a painting's materials is well established for preservation and art history issues. The task is however complex because of the highly ... [more ▼]

The necessity of understanding degradation and alteration processes in a painting's materials is well established for preservation and art history issues. The task is however complex because of the highly heterogeneous character of a paint layer, which consists of a mixture of pigments and a binder on a support. In this context we focus on a particular pigment, Prussian blue. Prussian blue is a hydrated ferric ferrocyanide complex, first synthesized in 1704 in Berlin. It has been widely used by artists until the 1970's. However reports of discoloration had already appeared in eighteenth and nineteenth century books. To date, little attention has been devoted to the understanding of the degradation processes of Prussian blue in paint layers. The preparation methods of Prussian blue were rapidly recognized as a contributory factor in the fading of the pigment because they lead to the introduction of impurities in its structure. The crystal structure of Prussian blue is notoriously complex because of the presence of vacancies and local disorder. Unresolved questions about the crystal structure of the soluble variety of Prussian blue, i.e., Prussian blue containing alkali cations, are still found in the literature. We reproduced modern and ancient preparation methods of Prussian blue and analyzed the obtained pigments by high-energy powder diffraction at the beamline ID11, ESRF, Grenoble and at the beamline CRISTAL, Soleil, Paris. The crystal structure of soluble Prussian blue was reviewed by Rietveld refinement and appears to contain approximately a quart of iron(II) sites vacant, similarly to the well-known insoluble crystal structure. The refinement of the pair distribution function extracted from the total scattering signal revealed a local structure different from the average one. The local arrangements are best described by combining three different substructures with different numbers of vacancies and vary upon the type of synthesis. The PDF analysis also evidenced the formation of nanocrystalline ferrihydrite and alumina hydrate in Prussian blue pigments synthesized according to eighteenth-century recipes. The local disorder and the presence of an undesirable iron compound in Prussian blue can help to better understand the degradation mechanisms in paint layers containing this pigment. [less ▲]

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See detailNon-destructive characterization of the Nizet Manuscript (XVIIIth century) : first results
Machowski, Mélanie ULg; Calvo Del Castillo, Helena ULg; Hocquet, François-Philippe et al

Poster (2012, June)

Detailed reference viewed: 41 (8 ULg)
See detailTiO2 templated multilayer films used as high efficiency photoelectrode in liquid or solid DSSCs
Dewalque, Jennifer ULg; Cloots, Rudi ULg; Mathis, François ULg et al

Conference (2012, April 10)

Mesoporous anatase thin films are very promising materials to act as electrode in dye-sensitized solar cells. Randomly oriented nanocrystalline TiO2 particles are usually used to prepare photoelectrodes ... [more ▼]

Mesoporous anatase thin films are very promising materials to act as electrode in dye-sensitized solar cells. Randomly oriented nanocrystalline TiO2 particles are usually used to prepare photoelectrodes with a thickness of 10-15 µm. Templated-assisted dip-coating techniques are used to obtain thin films with ordered porosity. However, monolayer films prepared by dip-coating from a solution suffer from a low quantity of active material with a limited surface area, leading to poor photovoltaic performances. Therefore a multilayer deposition process is needed to increase the film thickness along with surface area. Multilayer dip-coating procedures have already been reported but are usually characterized by a lack of linearity in the evolution of parameters (roughness, surface area, PV performances) as the number of layer increases. In this study, we investigate a dip-coating-based multilayer deposition technique delaying these limitations. First, the influence of the template on the film organization and porosity is studied in terms of long-range order, percentage of porosity, pore size, surface area and pores connectivity. Different techniques such as transmission electron microscopy (TEM), atmospheric poroellipsometry (AEP) and UV-visible absorption spectroscopy (UV-vis.) have been used to describe the microstructural features of the films. The film exhibiting the highest dye loading was selected and its thickness gradually increased up to 4 µm. Finally, the photovoltaic performances of the thick films (1 to 4 µm) have been evaluated in combination with the N719 dye and a liquid electrolyte and show excellent efficiency (6.1%) when compared to values reported in the literature. Such mesostructured films were compared in terms of photovoltaic performance with TiO2 nanoparticles films, generally used in DSSC. Films were further evaluated by Rutherford Backscattering Spectrometry (RBS) as high performance photoelectrode in solid-state DSSCs, in combination with Z907 dye and Spiro-OMeTAD as solid electrolyte. [less ▲]

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See detailNew external beam and particle detection set-up of Liège cyclotron – First applications of high energy beams to cultural heritage
Chene, Grégoire ULg; Bols, Stéphanie; Dupuis, Thomas ULg et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2012), 273

Improvements on the Liége cyclotron have yielded an energy resolution comparable to that of classic electrostatic accelerators. The latest upgrades of the High-Energy High-Resolution beam line (HE-HR) are ... [more ▼]

Improvements on the Liége cyclotron have yielded an energy resolution comparable to that of classic electrostatic accelerators. The latest upgrades of the High-Energy High-Resolution beam line (HE-HR) are presented which consist of the addition of both a new extraction nozzle for non-invasive in-air measurements and a new particle-detection setup developed to take full advantage of the increased probed thickness with depth sensitive analytical methods. The suitability of the new setup and the advantages provided by the larger flexibility in choosing both the proper particle with an extended energy available will be illustrated by discussing latest results of studies recently led on Roman gilding techniques on cultural heritage artifacts by means of “High-Energy” alpha backscattering spectrometry combined with PIXE. [less ▲]

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See detailSelection and heating of colouring materials in Mousterian level of es-Skhul (ca. 100 000 years B.P., Mount Carmel, Israel)
Salomon, Hélène ULg; Vignaud, Colette; Coquinot, Yvan et al

in Archaeometry (2012), 54(4), 698722

The transformation of yellow goethite into red hematite by heating has long been assumed for Palaeolithic red artefacts excavated close to fireplaces. However, this transformation is extremely rare. Using ... [more ▼]

The transformation of yellow goethite into red hematite by heating has long been assumed for Palaeolithic red artefacts excavated close to fireplaces. However, this transformation is extremely rare. Using SEM–FEG–EDX, PIXE–PIGE, TEM and mXRD, we characterized the mineralogical and chemical compositions of four microsamples of colouring materials from the Mousterian layer B in the es-Skhul rock-shelter, from about 100 kya ago. For some colouring materials, the Mousterian people of es-Skhul chose to gather remote yellow lumps for heating. Their significant transport distance provides evidence of the possible high cultural value of these colouring materials for transformation into red pigments. [less ▲]

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See detailStudy of medieval glass fragments originating from Savona (Italy) and their relation with the glass produced in Altare
Cagno, Simone; Badano Borondi, M.; Mathis, François ULg et al

in Journal of Archaeological Science (2012), 39(7), 2191-2197

Altare was in the medieval and post-medieval period an important glassmaking center in the Liguria region in Northern Italy. The first historical evidence of glassmaking in Altare is dated to the twelfth ... [more ▼]

Altare was in the medieval and post-medieval period an important glassmaking center in the Liguria region in Northern Italy. The first historical evidence of glassmaking in Altare is dated to the twelfth century. In spite of that, due to the continuity of glassmaking up to the present time and the contemporaneous intensive urbanization of the territory, no medieval glass from Altare or its immediate vicinity has been analyzed up to now. In this work, glass from archaeological excavations in the center of Savona, city with close ties with the glassmaking center, was studied. Glass fragments, dated from the tenth to the sixteenth century were selected from the collections of the Archaeological Museum in Savona and non-destructively analyzed with quantitative PIXE-PIGE. The resulting compositions, compared with known glass productions of the same time and evaluated on the basis of historical documents, offer an interesting panorama on the variety of glass circulation in Liguria. [less ▲]

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See detailContribution to the identification of α-, β- and ε-copper phthalocyanine blue pigments in modern artists' paints by X-ray powder diffraction, attenuated total reflectance micro-fourier transform infrared spectroscopy and micro-Raman spectroscopy
Defeyt, Catherine ULg; Vandenabeele, P.; Gilbert, Bernard ULg et al

in Journal of Raman Spectroscopy (2012), 43

Since the end of the 20th century, the α-, β- and ε-copper phthalocyanine (CuPc) blue pigments are widely used in modern artists' paints. The identification of the CuPc crystalline structure can provide ... [more ▼]

Since the end of the 20th century, the α-, β- and ε-copper phthalocyanine (CuPc) blue pigments are widely used in modern artists' paints. The identification of the CuPc crystalline structure can provide useful technical and chronological information for the study of works of art. Although when a CuPc blue pigment is identified, its crystalline structure often remains unspecified despite the interest for conservation science. In this study, X-ray powder diffraction, attenuated total reflectance micro-Fourier transform infrared spectroscopy and micro-Raman spectroscopy analyses have been carried out on 15 dry pigment samples of CuPc and acrylic, vinylic, alkyd, arabic gum and oil-based artists' paints. By using the polymorphic markers underlined for dry pigments, the CuPc crystalline structure has been successfully identified for most of the analysed artists' paints. However, according to the analytical technique used and the investigated paint sample, the obtained results largely differ. © 2012 John Wiley & Sons, Ltd. [less ▲]

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See detailX-ray production cross-sections measurements for high-energy alpha particle beams: New dedicated set-up and first results with aluminum
Dupuis, Thomas ULg; Chene, Grégoire ULg; Mathis, François ULg et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2011), 269(24), 29792983

The “IPNAS” laboratory, in collaboration with the “Centre Européen d’Archéométrie” is partly focused on material analysis by means of IBA techniques: PIXE, PIGE and RBS. A new transport beam line has been ... [more ▼]

The “IPNAS” laboratory, in collaboration with the “Centre Européen d’Archéométrie” is partly focused on material analysis by means of IBA techniques: PIXE, PIGE and RBS. A new transport beam line has been developed at our CGR-520 MeV cyclotron to analyze Cultural Heritage objects using these techniques. This facility allows us to produce proton and alpha particle beams with energies up to 20 MeV. A vacuum chamber dedicated to X-ray production and Non-Rutherford cross-section measurements has been recently constructed. After determination of the chamber’s geometry for X-ray detection using thin foils of several elements (11 ⩽ Z ⩽ 82) and 3 MeV proton beams, the measurement of the X-ray production cross-sections in the 6–12 MeV energy range has started using alpha particle beams on light element targets. These experiments contribute to the filling a serious lack of experimental values for alpha particles of this particular energy range in databases. The recent decision to focus our work on the alpha particle interaction with light elements was taken because of the high interest of the low Z elements in the field of archaeometry. [less ▲]

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See detailInsights into the ancient methods of preparation of Prussian blue pigments by high-resolution powder diffraction and PDF analysis
Samain, Louise ULg; Martinetto, Pauline; Bordet, Pierre et al

Conference (2011, September 09)

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See detailHandheld modern computer brings new features to portable X-ray fluorescence coating thickness measurement device
Carapelle, Alain ULg; Defise, Jean-Marc ULg; Strivay, David ULg et al

in Computer Physics Communications (2011), 182(6), 1304-1306

Detailed reference viewed: 33 (7 ULg)
See detailCaractérisation et vieillissement accéléré de pigments de bleu de Prusse synthétisés selon les méthodes de préparation anciennes et modernes
Samain, Louise ULg; Lauricella, Melina; Silversmit, Geert et al

Conference (2011, April 11)

Detailed reference viewed: 78 (14 ULg)