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Author Schalm, O.; Nuyts, G.; Janssens, K. pdf  url
doi  openurl
  Title Some critical observations about the degradation of glass : the formation of lamellae explained Type A1 Journal article
  Year 2021 Publication Journal Of Non-Crystalline Solids Abbreviated Journal J Non-Cryst Solids  
  Volume 569 Issue Pages 120984  
  Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)  
  Abstract This study demonstrates that the mechanism responsible for the transformation of glass into a degradation layer is pH-dependent. In acid conditions, the transformed glass is homogeneous and brittle. In mild alkaline conditions, transformed glass is heterogeneous due to the presence of lamellae composed of silica nanoparticles and the occurrence of Ca-rich inclusions. The fundamental difference between acid and alkaline conditions cannot be explained by the currently accepted degradation mechanism based on ion exchange. To explain this critical observation, we propose a refined degradation mechanism based on existing knowledge that involves several inwardly moving reaction fronts. The fronts responsible for the transformation of the silicate network into amorphous silica are also responsible for the morphology of the transformed glass. We have identified the feedback mechanism that explains the formation of lamellae in alkaline conditions.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000674487200009 Publication Date 2021-06-20  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 0022-3093 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.124 Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: 2.124  
  Call Number UA @ admin @ c:irua:179835 Serial 8551  
Permanent link to this record
 

 
Author Al-Emam, E.; Motawea, A.G.; Caen, J.; Janssens, K. url  doi
openurl 
  Title Soot removal from ancient Egyptian complex painted surfaces using a double network gel : empirical tests on the ceiling of the sanctuary of Osiris in the temple of Seti I-Abydos Type A1 Journal article
  Year 2021 Publication Heritage science Abbreviated Journal  
  Volume 9 Issue 1 Pages 1-10  
  Keywords A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)  
  Abstract In this study, we evaluated the ease of removal of soot layers from ancient wall paintings by employing double network gels as a controllable and safe cleaning method. The ceiling of the temple of Seti I (Abydos, Egypt) is covered with thick layers of soot; this is especially the case in the sanctuary of Osiris. These layers may have been accumulated during the occupation of the temple by Christians, fleeing the Romans in the first centuries A.D. Soot particulates are one of the most common deposits to be removed during conservation-restoration activities of ancient Egyptian wall paintings. They usually mask the painted reliefs and reduce the permeability of the painted surface. A Polyvinyl alcohol-borax/agarose (PVA-B/AG) double network gel was selected for this task since its properties were expected to be compatible with the cleaning treatment requirements. The gel is characterized by its flexibility, permitting to take the shape of the reliefs, while also having self-healing properties, featuring shape stability and an appropriate capacity to retain liquid. The gel was loaded with several cleaning reagents that proved to be effective for soot removal. Soot removal tests were conducted with these gel composites. The cleaned surfaces were evaluated with the naked eye, a digital microscope, and color measurements in order to select the best gel composite. The gel composite, loaded with a solution of 5% ammonia, 0.3% ammonium carbonate, and 0.3% EDTA yielded the most satisfactory results and allowed to safely remove a crust of thick soot layers from the surface. Thus, during the final phase of the study, it was used successfully to clean a larger area of the ceiling.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000604977300001 Publication Date 2021-01-04  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 2050-7445 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:174948 Serial 8557  
Permanent link to this record
 

 
Author Byrnes, I.; Rossbach, L.M.; Brede, D.A.; Grolimund, D.; Sanchez, D.F.; Nuyts, G.; Cuba, V.; Reinoso-Maset, E.; Salbu, B.; Janssens, K.; Oughton, D.; Scheibener, S.; Teien, H.-C.; Lind, O.C. url  doi
openurl 
  Title Synchrotron-based X-ray fluorescence imaging elucidates uranium toxicokinetics in Daphnia magna Type A1 Journal article
  Year 2023 Publication ACS nano Abbreviated Journal  
  Volume 17 Issue 6 Pages 5296-5305  
  Keywords A1 Journal article; Engineering sciences. Technology; Antwerp X-ray Imaging and Spectroscopy (AXIS)  
  Abstract A combination of synchrotron-based elemental anal-ysis and acute toxicity tests was used to investigate the biodistribution and adverse effects in Daphnia magna exposed to uranium nanoparticle (UNP, 3-5 nm) suspensions or to uranium reference (Uref) solutions. Speciation analysis revealed similar size distributions between exposures, and toxicity tests showed com-parable acute effects (UNP LC50: 402 mu g L-1 [336-484], Uref LC50: 268 mu g L-1 [229-315]). However, the uranium body burden was 3 -to 5-fold greater in UNP-exposed daphnids, and analysis of survival as a function of body burden revealed a similar to 5-fold higher specific toxicity from the Uref exposure. High-resolution X-ray fluorescence elemental maps of intact, whole daphnids from sublethal, acute exposures of both treatments revealed high uranium accumulation onto the gills (epipodites) as well as within the hepatic ceca and the intestinal lumen. Uranium uptake into the hemolymph circulatory system was inferred from signals observed in organs such as the heart and the maxillary gland. The substantial uptake in the maxillary gland and the associated nephridium suggests that these organs play a role in uranium removal from the hemolymph and subsequent excretion. Uranium was also observed associated with the embryos and the remnants of the chorion, suggesting uptake in the offspring. The identification of target organs and tissues is of major importance to the understanding of uranium and UNP toxicity and exposure characterization that should ultimately contribute to reducing uncertainties in related environmental impact and risk assessments.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000960129800001 Publication Date 2023-03-15  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 1936-0851 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 17.1 Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: 17.1; 2023 IF: 13.942  
  Call Number UA @ admin @ c:irua:196061 Serial 8631  
Permanent link to this record
 

 
Author Koldeweij, J.; Hoogstede, L.; Ilsink, M.; Janssens, K.; De Keyser, N.; Gotink, R.K.; Legrand, S.; Nauhaus, J.M.; van der Snickt, G.; Spronk, R. file  openurl
  Title The patron of Hieronymus Bosch's 'Last Judgment' triptych in Vienna Type A1 Journal article
  Year 2018 Publication The Burlington magazine Abbreviated Journal  
  Volume 160 Issue 1379 Pages 106-111  
  Keywords A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)  
  Abstract A technical examination of the Last Judgment triptych by Hieronymus Bosch in the Paintings Gallery of the Academy of Fine Arts, Vienna, has revealed a painted escutcheon with the coat of arms of the Burgundian court official Hippolyte de Berthoz underneath the current surface of the right outer wing. This allows him to be firmly identified as the painting's patron.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000458246800007 Publication Date  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 0007-6287; 2044-9925 ISBN Additional Links UA library record; WoS full record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:181267 Serial 8656  
Permanent link to this record
 

 
Author van Loon, A.; Noble, P.; de Man, D.; Alfeld, M.; Callewaert, T.; van der Snickt, G.; Janssens, K.; Dik, J. url  doi
openurl 
  Title The role of smalt in complex pigment mixtures in Rembrandt'sHomer1663: combining MA-XRF imaging, microanalysis, paint reconstructions and OCT Type A1 Journal article
  Year 2020 Publication Heritage science Abbreviated Journal  
  Volume 8 Issue 1 Pages 90-19  
  Keywords A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)  
  Abstract As part of the NWO Science4ArtsREVISRembrandtproject (2012-2018), novel chemical imaging techniques were developed and applied to the study of Rembrandt's late experimental painting technique (1651-1669). One of the unique features in his late paintings is his abundant use of smalt: a blue cobalt glass pigment that he often combined with organic lake pigments, earth pigments and blacks. Since most of these smalt-containing paints have discolored over time, we wanted to find out more about how these paintings may have originally looked, and what the role of smalt was in his paint. This paper reports on the use of smalt in complex pigment mixtures in Rembrandt'sHomer(1663), Mauritshuis, The Hague. Macroscopic X-ray fluorescence imaging (MA-XRF) assisted by computational analysis, in combination with SEM-EDX analysis of paint cross-sections, provides new information about the distribution and composition of the smalt paints in the painting. Paint reconstructions were carried out to investigate the effect of different percentages of smalt on the overall color, the drying properties, translucency and texture of the paint. Results show that the influence of (the originally blue) smalt on the intended color of the paint of theHomeris minimal. However, in mixtures with high percentages of smalt, or when combined with more transparent pigments, it was concluded that the smalt did produce a cooler and darker paint. It was also found that the admixture of opaque pigments reduced the translucent character of the smalt. The drying tests show that the paints with (cobalt-containing) smalt dried five times faster compared to those with glass (without cobalt). Most significantly, the texture of the paint was strongly influenced by adding smalt, creating a more irregular surface topography with clearly pronounced brushstrokes. Optical coherence tomography (OCT) was used as an additional tool to reveal differences in translucency and texture between the different paint reconstructions. In conclusion, this study confirmed earlier assumptions that Rembrandt used substantial amounts of smalt in his late paintings, not for its blue color, but to give volume and texture to his paints, to deepen their colors and to make them dry faster.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000565893700001 Publication Date 2020-09-04  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 2050-7445 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.5 Times cited Open Access  
  Notes Approved Most recent IF: 2.5; 2020 IF: NA  
  Call Number UA @ admin @ c:irua:171995 Serial 8659  
Permanent link to this record
 

 
Author Vanmeert, F.; Van der Snickt, G.; Legrand, S.; Janssens, K. isbn  openurl
  Title Velázquez? A portrait of Pope Innocent X : an X-ray imaging investigation (II) Type H3 Book chapter
  Year 2019 Publication Abbreviated Journal  
  Volume Issue Pages 132-141 T2 - Velázquez : Anregungen, Vorschläge, L  
  Keywords H3 Book chapter; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)  
  Abstract Encompassing a broad spectrum of methodological approaches and aims, the scholars contributing to this volume offer renewed perspectives on the multifaceted oeuvre of Diego Velázquez. The seventeenth-century artist’s exceptional religious works as well as his numerous portraits are examined within the social and historical context of Velázquez’s milieu which included both the Spanish court as well as circles comprising important intellectual figures of his time. Following a close investigation of his works, which also includes the results of recent technological examinations on his paintings, the contributors to this volume offer new, exciting findings and discussions on the inspirations, sources and possible intentions of Velázquez.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN ISBN 978-3-99020-155-8 Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:190783 Serial 8736  
Permanent link to this record
 

 
Author Janssens, K. pdf  doi
openurl 
  Title EXRS2022 : the 2022 edition of the European X-ray Spectrometry conference, held in Bruges, Belgium Type Editorial
  Year 2023 Publication X-ray spectrometry Abbreviated Journal  
  Volume 52 Issue 6 Pages 276-278  
  Keywords Editorial; Antwerp X-ray Imaging and Spectroscopy (AXIS)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001043528400001 Publication Date 2023-08-07  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 0049-8246 ISBN Additional Links UA library record; WoS full record  
  Impact Factor 1.2 Times cited Open Access Not_Open_Access  
  Notes Approved Most recent IF: 1.2; 2023 IF: 1.298  
  Call Number UA @ admin @ c:irua:198217 Serial 8865  
Permanent link to this record
 

 
Author Avranovich Clerici, E.; De Meyer, S.; Vanmeert, F.; Legrand, S.; Monico, L.; Miliani, C.; Janssens, K. url  doi
openurl 
  Title Multi-scale X-ray imaging of the pigment discoloration processes triggered by chlorine compounds in the Upper Basilica of Saint Francis of Assisi Type A1 Journal article
  Year 2023 Publication Molecules: a journal of synthetic chemistry and natural product chemistry Abbreviated Journal  
  Volume 28 Issue 16 Pages 6106-6123  
  Keywords A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS)  
  Abstract In this paper, the chromatic alteration of various types of paints, present on mural painting fragments derived from the vaults of The Upper Basilica of Saint Francis of Assisi in Italy (12th-13th century), is studied using synchrotron radiation. Six painted mural fragments, several square centimeters in size, were available for analysis, originating from the ceiling paintings attributed to Cimabue and Giotto; they correspond to originally white, blue/green, and brown/yellow/orange areas showing discoloration. As well as collecting macroscopic X-ray fluorescence and diffraction maps from the entire fragments in the laboratory and at the SOLEIL synchrotron, corresponding paint cross-sections were also analyzed using microscopic X-ray fluorescence and powder diffraction mapping at the PETRA-III synchrotron. Numerous secondary products were observed on the painted surfaces, such as (a) copper tri-hydroxychloride in green/blue areas; (b) corderoite and calomel in vermillion red/cinnabar-rich paints; (c) plattnerite and/or scrutinyite assumed to be oxidation products of (hydro)cerussite (2PbCO(3)center dot Pb(OH)(2)) in the white areas, and (d) the calcium oxalates whewellite and weddellite. An extensive presence of chlorinated metal salts points to the central role of chlorine-containing compounds during the degradation of the 800-year-old paint, leading to, among other things, the formation of the rare mineral cumengeite (21PbCl(2)center dot 20Cu(OH) (2) center dot 6H(2)O).  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001056388600001 Publication Date 2023-08-17  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 1420-3049 ISBN Additional Links UA library record; WoS full record  
  Impact Factor 4.6 Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: 4.6; 2023 IF: 2.861  
  Call Number UA @ admin @ c:irua:199265 Serial 8902  
Permanent link to this record
 

 
Author Monico, L.; d'Acapito, F.; Cotte, M.; Janssens, K.; Romani, A.; Ricci, G.; Miliani, C.; Cartechini, L. pdf  url
doi  openurl
  Title Total electron yield (TEY) detection mode Cr K-edge XANES spectroscopy as a direct method to probe the composition of the surface of darkened chrome yellow (PbCr1-xSxO4) and potassium chromate paints Type A1 Journal article
  Year 2023 Publication Nuclear instruments and methods in physics research: B: beam interactions with materials and atoms Abbreviated Journal  
  Volume 539 Issue Pages 141-147  
  Keywords A1 Journal article; Engineering sciences. Technology; Antwerp X-ray Imaging and Spectroscopy (AXIS)  
  Abstract The darkening of chromate-pigments, including chrome yellows (PbCr1-xSxO4), is a surface phenomenon affecting late 19th-early 20th c. paintings, such as those by Van Gogh. Exploring analytical strategies that contribute to a deep understanding of darkening is therefore significant for the long-term conservation of unique masterpieces. Here, we examined the capabilities of Cr K-edge XANES spectroscopy collected at the same time in X-ray fluorescence yield (XFY) and total electron yield (TEY) detection modes to selectively study the surface composition of darkened oil paint mock-ups composed of chrome yellow (PbCr0.2S0.8O4) or potassium chromate. By discussing advantages and drawbacks in using XFY/TEY modes in relation to XFY & mu;-XANES analysis from sectioned samples, we aim at assessing if TEY-XANES spectroscopy: (i) is a selective surface method to determine the abundance of different Cr-species from paint fragments; (ii) can contribute to optimize the analytical strategy by limiting time consuming sample preparation procedures; (iii) can decrease the probability of radiation damage.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001041485400001 Publication Date 2023-04-10  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 0168-583x ISBN Additional Links UA library record; WoS full record  
  Impact Factor 1.3 Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: 1.3; 2023 IF: 1.109  
  Call Number UA @ admin @ c:irua:198427 Serial 8944  
Permanent link to this record
 

 
Author Ortega Saez, N.; Arno, R.; Marchetti, A.; Cauberghs, S.; Janssens, K.; Van der Snickt, G.; Al-Emam, E. url  doi
openurl 
  Title Towards a novel strategy for soot removal from water-soluble materials : the synergetic effect of hydrogels and cyclomethicone on gelatine emulsion-based photographs Type A1 Journal article
  Year 2023 Publication Heritage science Abbreviated Journal  
  Volume 11 Issue 1 Pages 78-17  
  Keywords A1 Journal article; Engineering sciences. Technology; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)  
  Abstract Gels are a popular cleaning method for paper conservators and a lot of research has been done concerning gel cleaning of paper objects over the last 15 years. Despite the close interconnection between the conservation fields of paper and photographic material, research on using gels for cleaning photographs is very scarce. However, gels can provide an excellent cleaning method for photographic material. Cleaning silver gelatine prints with aqueous solvents is very complex due to the hydrophilic properties and fragility of the gelatine layer which makes mechanical cleaning difficult. The properties of gels ensure better control over the flow and evaporation of the solvent, facilitating the cleaning process. This study is the first insight into the viability of using gellan gum gel and polyvinyl acetate-borax (PVAc-borax) gel to clean contaminants from the surface of silver gelatine photographs. It is based on self-made samples that were artificially aged and contaminated with soot. Water, ethanol (EtOH), and Kodak Photo-flo were studied as solvents to remove the soot from the silver gelatine-based prints. These solvents were loaded into the aforementioned gels and applied to the samples in two different methods. These gel cleaning methods were subsequently compared with traditional cleaning methods. In addition, the usage of cyclomethicone D4 as a protective mask for the gelatine layer was studied. Measuring methods used to evaluate the cleaning were visual comparison, microscopic observation, and densitometry. ATR-FTIR measurements were also conducted to investigate potential side-effects of the cleaning methods on the prints, such as unwanted chemical transformations or the presence of gel residues after the treatments. Most of the gel cleaning methods within this study proved to be inadequate, with the exception of the gellan gum gel loaded with 30% EtOH. It was used as a granulated gel applied mechanically on a print saturated with cyclomethicone (octamethylcyclotetrasiloxane D4). Cyclomethicone proved to be a very effective protective barrier for the water-sensitive gelatine layer with minimal reduction in cleaning effectiveness.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000970139500001 Publication Date 2023-04-18  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 2050-7445 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.5 Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: 2.5; 2023 IF: NA  
  Call Number UA @ admin @ c:irua:196445 Serial 8945  
Permanent link to this record
 

 
Author Broers, F.T.H.; Janssens, K.; Weker, J.N.; Webb, S.M.; Mehta, A.; Meirer, F.; Keune, K. url  doi
openurl 
  Title Two pathways for the degradation of orpiment pigment (As₂S₃) found in paintings Type A1 Journal article
  Year 2023 Publication Journal of the American Chemical Society Abbreviated Journal  
  Volume 145 Issue 16 Pages 8847-8859  
  Keywords A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS)  
  Abstract Paintings are complex objects containing many different chemical compounds that can react over time. The degradation of arsenic sulfide pigments causes optical changes in paintings. The main degradation product was thought to be white arsenolite (As2O3), but previous research also showed the abundant presence of As(V) species. In this study, we investigate the influence of the presence of a medium on the degradation mechanism of orpiment (As2S3) using synchrotron radiation (SR)-based tomographic transmission X-ray microscopy, SR-based micro-X-ray fluorescence, and Xray absorption near edge structure spectroscopy. Upon direct illumination of dry orpiment powder using UV-visible light, only the formation of As2O3 was observed. When As2S3 was surrounded by a medium and illuminated, As2O3 was only observed in the area directly exposed to light, while As(V) degradation species were found elsewhere in the medium. Without accelerated artificial light aging, As(V)(aq) species are formed and migrate throughout the medium within weeks after preparation. In both scenarios, the As(V) species form via intermediate As(III)(aq) species and the presence of a medium is necessary. As(V)(aq) species can react with available cations to form insoluble metal arsenates, which induces stress within the paint layers (leading to, e.g., cracks and delamination) or can lead to a visual change of the image of the painting.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000974346900001 Publication Date 2023-04-14  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 0002-7863 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 15 Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: 15; 2023 IF: 13.858  
  Call Number UA @ admin @ c:irua:196762 Serial 8948  
Permanent link to this record
 

 
Author Mayda, S.; Monico, L.; Krishnan, D.; De Meyer, S.; Cotte, M.; Garrevoet, J.; Falkenberg, G.; Sandu, I.C.A.; Partoens, B.; Lamoen, D.; Romani, A.; Miliani, C.; Verbeeck, J.; Janssens, K. pdf  doi
openurl 
  Title A combined experimental and computational approach to understanding CdS pigment oxidation in a renowned early 20th century painting Type A1 Journal article
  Year 2023 Publication Chemistry of materials Abbreviated Journal  
  Volume 35 Issue 24 Pages 10403-10415  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Antwerp X-ray Imaging and Spectroscopy (AXIS)  
  Abstract Cadmium sulfide (CdS)-based yellow pigments have been used in a number of early 20th century artworks, including The Scream series painted by Edvard Munch. Some of these unique paintings are threatened by the discoloration of these CdS-based yellow oil paints because of the oxidation of the original sulfides to sulfates. The experimental data obtained here prove that moisture and cadmium chloride compounds play a key role in promoting such oxidation. To clarify how these two factors effectively prompt the process, we studied the band alignment between CdS, CdCl2, and Cd-(OH)Cl as well as the radicals center dot OH and H3O center dot by density functional theory (DFT) methods. Our results show that a stack of several layers of Cd-(OH)Cl creates a pocket of positive holes at the Cl-terminated surface and a pocket of electrons at the OH-terminated surface by leading in a difference in ionization energy at both surfaces. The resulting band alignment indicates that Cd-(OH)Cl can indeed play the role of an oxidative catalyst for CdS in a moist environment, thus providing an explanation for the experimental evidence.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001133000900001 Publication Date 2023-12-08  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 0897-4756; 1520-5002 ISBN Additional Links UA library record; WoS full record  
  Impact Factor Times cited Open Access  
  Notes The experimental research on the cadmium yellow powders/paint mock-ups and The Scream (ca. 1910) was financially supported by the European Union, research projects IPERION-CH (H2020-INFRAIA-2014-2015, GA no. 654028) and IPERION-HS (H2020-INFRAIA-2019-1, GA no. 871034) and the project AMIS within the program Dipartimenti di Eccellenza 2018-2022 (funded by MUR and the University of Perugia). For the beamtime grants received, the authors thank the ESRF-ID21 beamline (experiments HG64 and HG95), the DESY-P06 beamline, a member of the Helmholtz Association HGF (experiments I-20130221 EC and I-20160126 EC), and the project CALIPSOplus under the GA no. 730872 from the E.U. Framework Programme for Research and Innovation Horizon 2020. All of the staff of the MUNCH Museum (Conservation Department) is acknowledged for their collaboration. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the FWO – Vlaanderen and the Flemish Government, Department EWI. Approved no  
  Call Number UA @ admin @ c:irua:202836 Serial 8999  
Permanent link to this record
 

 
Author Alvarez-Martin, A.; Quanico, J.; Scovacricchi, T.; Avranovich Clerici, E.; Baggerman, G.; Janssens, K. pdf  doi
openurl 
  Title Chemical mapping of the degradation of geranium lake in paint cross sections by MALDI-MSI Type A1 Journal article
  Year 2023 Publication Analytical chemistry Abbreviated Journal  
  Volume 95 Issue 49 Pages 18215-18223  
  Keywords A1 Journal article; Antwerp X-ray Imaging and Spectroscopy (AXIS); Ecosphere  
  Abstract Matrix assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) has become a powerful method to extract spatially resolved chemical information in complex materials. This study provides the first use of MALDI-MSI to define spatial–temporal changes in oil paints. Due to the highly heterogeneous nature of oil paints, the sample preparation had to be optimized to prevent molecules from delocalizing. Here, we present a new protocol for the layer-specific analysis of oil paint cross sections achieving a lateral resolution of 10 μm and without losing ionization efficiency due to topographic effects. The efficacy of this method was investigated in oil paint samples containing a mixture of two historic organic pigments, geranium lake and lead white, a mixture often employed in the work of painter Vincent Van Gogh. This methodology not only allows for spatial visualization of the molecules responsible for the pink hue of the paint but also helps to elucidate the chemical changes behind the discoloration of paintings with this composition. The results demonstrate that this approach provides valuable molecular compositional information about the degradation pathways of pigments in specific paint layers and their interaction with the binding medium and other paint components and with light over time. Since a spatial correlation between molecular species and the visual pattern of the discoloration pattern can be made, we expect that mass spectrometry imaging will become highly relevant in future degradation studies of many more historical pigments and paints.  
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  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001142876000001 Publication Date 2023-11-23  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 0003-2700; 5206-882x ISBN Additional Links UA library record; WoS full record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:201644 Serial 9007  
Permanent link to this record
 

 
Author Broers, F.T.H.; Verslype, I.; Bossers, K.W.; Vanmeert, F.; Gonzalez, V.; Garrevoet, J.; van Loon, A.; va Duijn, E.; Krekeler, A.; De Keyser, N.; Steeman, I.; Noble, P.; Janssens, K.; Meirer, F.; Keune, K. url  doi
openurl 
  Title Correlated x-ray fluorescence and ptychographic nano-tomography on Rembrandt's The Night Watch reveals unknown lead “layer” Type A1 Journal article
  Year 2023 Publication Science Advances Abbreviated Journal  
  Volume 9 Issue 50 Pages eadj9394-13  
  Keywords A1 Journal article; Engineering sciences. Technology; Art; Antwerp X-ray Imaging and Spectroscopy (AXIS)  
  Abstract The Night Watch, one of the most famous masterpieces by Rembrandt, is the subject of a large research and conservation project. For the conservation treatment, it is of great importance to understand its current condition. Correlated nano-tomography using x-ray fluorescence and ptychography revealed a-so far unknown-lead-containing “layer”, which likely acts as a protective impregnation layer applied on the canvas before the quartz-clay ground was applied. This layer might explain the presence of lead soap protrusions in areas where no other lead components are present. In addition to the three-dimensional elemental mapping, ptychography visualizes and quantifies components not detectable by hard x-ray fluorescence such as the organic fraction and quartz. The first-time use of this combination of synchrotron-based techniques on a historic paint micro-sample shows it to be an important tool to better interpret the results of noninvasive imaging techniques operating on the macroscale.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001142514700010 Publication Date 2023-12-15  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 2375-2548 ISBN Additional Links UA library record; WoS full record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:203849 Serial 9016  
Permanent link to this record
 

 
Author Koirala, B.; Rasti, B.; Bnoulkacem, Z.; De Lima Ribeiro, A.; Madriz, Y.; Herrmann, E.; Gestels, A.; De Kerf, T.; Janssens, K.; Steenackers, G.; Gloaguen, R.; Scheunders, P. pdf  doi
openurl 
  Title An extensive multisensor hyperspectral benchmark datasets of intimate mixtures of mineral powders Type P1 Proceeding
  Year 2023 Publication Abbreviated Journal  
  Volume Issue Pages 5890-5893 T2 - IGARSS 2023 - 2023 IEEE Internation  
  Keywords P1 Proceeding; Vision lab; Antwerp X-ray Imaging and Spectroscopy (AXIS)  
  Abstract Since many materials behave as heterogeneous intimate mixtures with which each photon interacts differently, the relationship between spectral reflectance and material composition is very complex. Quantitative validation of spectral unmixing algorithms requires high-quality ground truth fractional abundance data, which are very difficult to obtain.In this work, we generated a comprehensive hyperspectral dataset of intimate mineral powder mixtures by homogeneously mixing five different clay powders (Kaolin, Roof clay, Red clay, mixed clay, and Calcium hydroxide). In total 325 samples were prepared. Among the 325 samples, 60 mixtures were binary, 150 were ternary, 100 were quaternary, and 15 were quinary. For each mixture (and pure clay powder), reflectance spectra are acquired by 13 different sensors, with a broad wavelength range between the visible and the long-wavelength infrared regions (i.e., between 350 nm and 15385 nm) and with a large variation in sensor types, platforms, and acquisition conditions. We will make this dataset public, to be used by the community for the validation of nonlinear unmixing methodologies (https://github.com/VisionlabUA/Multisensor_datasets)  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date 2023-10-20  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 979-83-503-2010-7 ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:201596 Serial 9035  
Permanent link to this record
 

 
Author Koirala, B.; Rasti, B.; Bnoulkacem, Z.; de Lima Ribeiro, A.; Madriz, Y.; Herrmann, E.; Gestels, A.; De Kerf, T.; Lorenz, S.; Fuchs, M.; Janssens, K.; Steenackers, G.; Gloaguen, R.; Scheunders, P. pdf  doi
openurl 
  Title A multisensor hyperspectral benchmark dataset for unmixing of intimate mixtures Type A1 Journal article
  Year 2024 Publication IEEE sensors journal Abbreviated Journal  
  Volume 24 Issue 4 Pages 4694-4710  
  Keywords A1 Journal article; Engineering sciences. Technology; Vision lab; Antwerp X-ray Imaging and Spectroscopy (AXIS)  
  Abstract Optical hyperspectral cameras capture the spectral reflectance of materials. Since many materials behave as heterogeneous intimate mixtures with which each photon interacts differently, the relationship between spectral reflectance and material composition is very complex. Quantitative validation of spectral unmixing algorithms requires high-quality ground truth fractional abundance data, which are very difficult to obtain. In this work, we generated a comprehensive laboratory ground truth dataset of intimately mixed mineral powders. For this, five clay powders (Kaolin, Roof clay, Red clay, mixed clay, and Calcium hydroxide) were mixed homogeneously to prepare 325 samples of 60 binary, 150 ternary, 100 quaternary, and 15 quinary mixtures. Thirteen different hyperspectral sensors have been used to acquire the reflectance spectra of these mixtures in the visible, near, short, mid, and long-wavelength infrared regions (350-15385) nm. Overlaps in wavelength regions due to the operational ranges of each sensor and variations in acquisition conditions resulted in a large amount of spectral variability. Ground truth composition is given by construction, but to verify that the generated samples are sufficiently homogeneous, XRD and XRF elemental analysis is performed. We believe these data will be beneficial for validating advanced methods for nonlinear unmixing and material composition estimation, including studying spectral variability and training supervised unmixing approaches. The datasets can be downloaded from the following link: https://github.com/VisionlabHyperspectral/Multisensor_datasets.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date 2023-12-28  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 1530-437x; 1558-1748 ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:203094 Serial 9059  
Permanent link to this record
 

 
Author Derks, K.; Youchaeva, M.; Van der Snickt, G.; Van der Stighelen, K.; Janssens, K. url  openurl
  Title Reconstructing Sweerts : practical insights into the historical dark halo technique based on paint reconstructions Type P1 Proceeding
  Year 2024 Publication Abbreviated Journal  
  Volume Issue Pages 259-271 T2 - Alla maniera : technical art history  
  Keywords P1 Proceeding; Engineering sciences. Technology; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 978-90-429-5216-4 ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:203062 Serial 9082  
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