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Author Meulebroeck, W.; Cosyns, P.; Baert, K.; Wouters, H.; Cagno, S.; Janssens, K.; Terryn, H.; Nys, K.; Thienpont, H.
Title Optical spectroscopy as a rapid and low-cost tool for the first-line analysis of glass artefacts : a step-by-step plan for Roman green glass Type A1 Journal article
Year 2011 Publication Journal of archaeological science Abbreviated Journal J Archaeol Sci
Volume 38 Issue 9 Pages 2387-2398
Keywords A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Archaeometric research on glass artefacts is continuously evolving and is converging towards a multidisciplinary research domain where different types of techniques are applied depending on the questions asked and the circumstances involved. The technique described in this work is optical spectroscopy. The benefit of this technique being the possibility of building up a knowledge database for a large amount of material in a relatively short period of time and with a relatively limited budget. This is of particular interest for the investigation of extensive and/or unexplored glass collections where a first-line analysis of artefacts could facilitate the selection of material needing further and more detailed examination. This publication explores the extent to which optical spectroscopy can be used for a first-line analysis of green coloured glass artefacts from the Roman period. It is shown that the colour coordinates calculated from the measured transmission spectrum could reveal information about the fragment under study. In particular it is shown that 1) based on the position of the calculated colour values on the colour diagram (CIE1931) one could easily know whether the artefact was coloured using only iron or if copper oxides were also present. In the case of the artefact owing its colour solely to the presence of iron, the distance between the measured colour values and the colour diagrams white point can roughly indicate the iron concentration of the sample; 2) artefacts that were fabricated under similar furnace conditions can also be identified on the colour diagram; 3) samples with identical compositions and fabrication conditions but with different sample thickness, gave rise to a variation in the colour coordinates, thus allowing optical spectroscopy to help identify fragments which might belong to the same object.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000293551200037 Publication Date 2011-05-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0305-4403 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.602 Times cited 18 Open Access
Notes ; The authors would like to express their gratitude to the Vrije Universiteit Brussel for funding this research in the framework of HOA15, a “Horizontal Research Action” which encourages collaboration between research groups from different departments within the same University having expertise in specific research disciplines and also to the OZR-project 1247 BOF. The authors are also very grateful to the following persons for having permitted the study of their material: Rica Annaert and Sofie Vanhoutte of the “Vlaams lnstituut voor Onroerend Erfgoed (VIOE): Grobbendonk, Matagne-la-Petite, Oudenburg; Jean-Louis Antoine of the Musee Archeologique Namur: Nismes; Tom Debruyne of the ”Erfgoedcel“ Tienen: Tienen: Marc Rogge and Kurt Braeckman of the ”Provinciaal Archeologisch Museum (PAM)": Kruishoutem, Velzeke; Walter Sevenants: Rumst and Anne de Pyre-Gysel from the Musee Romain d'Avenches: Avenches. ; Approved (down) Most recent IF: 2.602; 2011 IF: 1.914
Call Number UA @ admin @ c:irua:92389 Serial 5756
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Author Cagno, S.; Mendera, M.; Jeffries, T.; Janssens, K.
Title Raw materials for medieval to post-medieval Tuscan glassmaking : new insight from LA-ICP-MS analyses Type A1 Journal article
Year 2010 Publication Journal of archaeological science Abbreviated Journal J Archaeol Sci
Volume 37 Issue 12 Pages 3030-3036
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract LA-ICP-MS analyses were performed on a set of Tuscan (post) medieval archaeological glass finds dated to the 1316th century in order to quantitatively determine the trace element contents. The results are used for defining and distinguishing several compositional groups. The trace element data are consistent with the distinctions obtained by considering the major element data determined via quantitative SEM-EDX, but allow to obtain new insights into the nature and quality of the silica sources employed and the presumed method of ash purification.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000283903500008 Publication Date 2010-07-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0305-4403 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.602 Times cited 38 Open Access
Notes ; This research was supported by the Interuniversity Attraction Poles Program – Belgian Science Policy (IUAP VI/16). The text also presents results of GOA “Atom” (Research Fund University of Antwerp, Belgium) and of FWO (Brussels, Belgium) projects no. G.0177.03, G.0103.04 and G.0689.06. ; Approved (down) Most recent IF: 2.602; 2010 IF: 1.710
Call Number UA @ admin @ c:irua:85814 Serial 5802
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Author Aerts, A.; Janssens, K.; Adams, F.
Title Trace-level microanalysis of Roman glass from Khirbet Qumran, Israel Type A1 Journal article
Year 1999 Publication Journal of archaeological science Abbreviated Journal J Archaeol Sci
Volume 26 Issue Pages 883-891
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000082470800005 Publication Date 2002-09-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0305-4403 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.602 Times cited Open Access
Notes Approved (down) Most recent IF: 2.602; 1999 IF: NA
Call Number UA @ admin @ c:irua:25299 Serial 5881
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Author Ortega Saez, N.; Arno, R.; Marchetti, A.; Cauberghs, S.; Janssens, K.; Van der Snickt, G.; Al-Emam, E.
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.
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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
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 (down) Most recent IF: 2.5; 2023 IF: NA
Call Number UA @ admin @ c:irua:196445 Serial 8945
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Author Al-Emam, E.; Soenen, H.; Caen, J.; Janssens, K.
Title Characterization of polyvinyl alcohol-borax/agarose (PVA-B/AG) double network hydrogel utilized for the cleaning of works of art Type A1 Journal article
Year 2020 Publication Heritage science Abbreviated Journal
Volume 8 Issue 1 Pages 106
Keywords A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
Abstract Since cleaning of artworks may cause undesirable physicochemical alterations and is a nonreversible procedure, it is mandatory to adopt the proper cleaning procedure. Such a procedure should remove undesired materials whilst preserving the original surface. In this regard, numerous gels have been developed and exploited for the cleaning of various artwork surfaces. Lately, agarose (AG) and polyvinyl alcohol-borax (PVA-B) hydrogels have been widely employed as cleaning tools by conservators. Both hydrogels show some limitations in specific cleaning practices. In this work, we investigated the influence of including increased levels of agarose into PVA-B systems. For this reason, we performed a detailed characterization on the double network (DN) hydrogel including the chemical structure, the liquid phase retention, the rheological behavior, and the self-healing behavior of various PVA-B/AG double network hydrogels. These new hydrogels revealed better properties than PVA-B hydrogels and obviated their limitations. The inclusion of AG into PVA-B systems enhanced the liquid retention capacity, shape-stability, and mechanical strength of the blend. Furthermore, AG minimized the expelling/syneresis issue that occurs when loading PVA-B systems with low polarity solvents or chelating agents. The resultant double network hydrogel exhibits relevant self-healing properties. The PVA-B/AG double network is a new and useful cleaning tool that can be added to the conservators' tool-kit. It is ideal for cleaning procedures dealing with porous and complex structured surfaces, vertical surfaces and for long time applications.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000580572500001 Publication Date 2020-10-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2050-7445 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.5 Times cited 1 Open Access
Notes ; Ehab Al-Emam thanks the Egyptian Ministry of Higher Education for funding his Ph.D. scholarship in addition to being grateful to University of Antwerp for additional funding. ; Approved (down) Most recent IF: 2.5; 2020 IF: NA
Call Number UA @ admin @ c:irua:173594 Serial 6466
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Author Simonsen, K.P.; Poulsen, J.N.; Vanmeert, F.; Ryhl-Svendsen, M.; Bendix, J.; Sanyova, J.; Janssens, K.; Mederos-Henry, F.
Title Formation of zinc oxalate from zinc white in various oil binding media: the influence of atmospheric carbon dioxide by reaction with 13CO2 Type A1 Journal article
Year 2020 Publication Heritage science Abbreviated Journal
Volume 8 Issue 1 Pages 126
Keywords A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract The formation of metal oxalates in paintings has recently gained a great deal of interest within the field of heritage science as several types of oxalate compounds have been identified in oil paintings. The present work investigates the formation of metal oxalates in linseed oil in the presence of the artists' pigments zinc white, calcite, lead white, zinc yellow, chrome yellow, cadmium yellow, cobalt violet, and verdigris. The oil paint films were artificially photo-aged by exposure to UVA light at low and high relative humidity, and afterwards analysed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The results showed that, compared to the other pigments investigated, zinc white is especially prone to metal oxalate formation and that high humidity is a crucial factor in this process. Consequently, the reactivity and photo-aging of ZnO in various oil binding media was investigated further under simulated solar radiation and at high relative humidity levels. ATR-FTIR showed that zinc oxalate is formed in all oil binding media while X-ray powder diffraction (PXRD) revealed it was mainly present in an amorphous state. To examine whether atmospheric CO2(g) has any influence on the formation of zinc oxalate, experiments with isotopically enriched (CO2(g))-C-13 were performed. Based on ATR-FTIR measurements, neither (ZnC2O4)-C-13 nor (ZnCO3)-C-13 were formed which suggests that the carbon source for the oxalate formation is most likely the paint itself (and its oil component) and not the surrounding atmosphere.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000596527000001 Publication Date 2020-12-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
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 (down) Most recent IF: 2.5; 2020 IF: NA
Call Number UA @ admin @ c:irua:174381 Serial 7979
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Author van Loon, A.; Noble, P.; de Man, D.; Alfeld, M.; Callewaert, T.; van der Snickt, G.; Janssens, K.; Dik, J.
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.
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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
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 (down) Most recent IF: 2.5; 2020 IF: NA
Call Number UA @ admin @ c:irua:171995 Serial 8659
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Author Cagno, S.; Hellemans, K.; Lind, O.C.; Skipperud, L.; Janssens, K.; Salbu, B.
Title LA-ICP-MS for Pu source identification at Mayak PA, the Urals, Russia Type A1 Journal article
Year 2014 Publication Environmental science : processes & impacts Abbreviated Journal Environ Sci-Proc Imp
Volume 16 Issue 2 Pages 306-312
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Information on Pu in environmental samples is traditionally based on the determination of the 240+239PU activity via Alpha Spectrometry (AS). A large number of alpha spectrometry sources (planchettes) containing radiochemically separated Pu are therefore stored worldwide and are available for further analyses. These archive samples represent a resource from which valuable information on isotopic composition of alpha emitters including Pu can be obtained. The relative abundances of Pu isotopes can be used to trace specific Pu sources and characterize the relative contributions of different Pu sources in a sample. Thus, in addition to the total 239+240PU activity, determination of the Pu-240/Pu-239 ratio can provide valuable information on the nature of the Pu emitting sources. The Pu isotopic ratios can be determined by mass spectrometry techniques such as Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICPMS) or Accelerator Mass Spectrometry (AMS) that require dissolution and complete destruction of the material deposited on the planchettes. In this study Laser Ablation (LA)-quadrupole-ICP-MS has been employed for the analysis of Pu-239/Pu-240 ratios from alpha-planchettes prepared from samples originating from the Mayak PA nuclear facility, Russia. The results are compared with data from AMS and show that the Pu-240/Pu-239 ratios obtained by LA-ICP-MS can be utilized to distinguish weapons-grade Pu from civil reprocessing sources. Moreover, isotope ratio mapping can also be performed across the planchettes, allowing e.g. the visualization of possible inhomogeneities in the Pu-isotope distribution on their surface. Thus, this solid sample technique can be applied to extract additional information from existing archives of samples.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000331504100015 Publication Date 2013-12-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2050-7887; 2050-7895 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.592 Times cited 10 Open Access
Notes ; This work was supported by the Research Council of Norway through its Centres of Excellence funding scheme, project number 223268/F50, and the Hercules fund, Brussels (grant A11/0387). ; Approved (down) Most recent IF: 2.592; 2014 IF: 2.171
Call Number UA @ admin @ c:irua:115791 Serial 5684
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Author Terzano, R.; Spagnuolo, M.; Medici, L.; Tateo, F.; Vekemans, B.; Janssens, K.; Ruggiero, P.
Title Spectroscopic investigation on the chemical forms of Cu during the synthesis of zeolite X at low temperature Type A1 Journal article
Year 2006 Publication Applied geochemistry Abbreviated Journal Appl Geochem
Volume 21 Issue 6 Pages 993-1005
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000238827500010 Publication Date 2006-05-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0883-2927 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.581 Times cited 15 Open Access
Notes Approved (down) Most recent IF: 2.581; 2006 IF: 1.866
Call Number UA @ admin @ c:irua:59636 Serial 5841
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Author van Grieken, R.; Bogaerts, A.; Janssens, K.
Title Editorial Type Editorial
Year 2006 Publication Spectrochimica acta: part A: molecular spectroscopy Abbreviated Journal Spectrochim Acta A
Volume 64 Issue 5 Pages 1089
Keywords Editorial; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000240093100001 Publication Date 2006-07-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1386-1425; ISBN Additional Links UA library record; WoS full record
Impact Factor 2.536 Times cited Open Access
Notes Approved (down) Most recent IF: 2.536; 2006 IF: 1.270
Call Number UA @ lucian @ c:irua:58915 Serial 788
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Author Schalm, O.; Caluwé, D.; Wouters, H.; Janssens, K.; Verhaeghe, F.; Pieters, M.
Title Chemical composition and deterioration of glass excavated in the 15th-16th century fishermen town of Raversijde (Belgium) Type A1 Journal article
Year 2004 Publication Spectrochimica acta: part A: molecular and biomolecular spectroscopy Abbreviated Journal Spectrochim Acta A
Volume 59 Issue Pages 1647-1656
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract The chemical composition, as determined by electron probe X-ray microanalysis of a series of ca. 100 archaeological glass fragments, excavated at the Raversijde site (Belgium) is discussed. In the 15th-16th century, Raversijde was a flourishing fishermen town located on the shore of the North Sea, close to the city of Ostend. As a consequence of several battles that were fought in its vicinity, the site was abandoned in the 16th century and was not occupied since then. It is one of the rare archaeological sites in Europe that contains a significant amount of information on the daily life inside a small but affluent medieval community. A comparison of the chemical composition of fragments of vessels and window glass encountered in Raversijde to those found in urban centres in Belgium and to literature date on German and French archaeological finds shows that glass made with wood ash dominates. Usually, it concerns artifacts with a predominantly utilitarian use. A few objects made with sodic (i.e., Na-rich) glass were also encountered, likely to have been imported from Venice during the 15th century or in later periods from an urban centre such as Antwerp, where Facon-de-Venice glass manufacturing activities were established near the start of the 16th century. (C) 2004 Elsevier B.V. All rights reserved.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000224848000021 Publication Date 2004-10-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1386-1425 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.536 Times cited 26 Open Access
Notes Approved (down) Most recent IF: 2.536; 2004 IF: 1.188
Call Number UA @ admin @ c:irua:49011 Serial 5512
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Author Janssens, K.; Proost, K.; Falkenberg, G.
Title Confocal microscopic X-ray fluorescence at the HASYLAB microfocus beamline: characteristics and possibilities Type A1 Journal article
Year 2004 Publication Spectrochimica acta: part A: molecular and biomolecular spectroscopy Abbreviated Journal Spectrochim Acta A
Volume 59 Issue Pages 1637-1645
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000224848000020 Publication Date 2004-10-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1386-1425 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.536 Times cited 102 Open Access
Notes Approved (down) Most recent IF: 2.536; 2004 IF: 1.188
Call Number UA @ admin @ c:irua:49010 Serial 5555
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Author Derks, K.; van der Snickt, G.; Legrand, S.; van der Stighelen, K.; Janssens, K.
Title The dark halo technique in the oeuvre of Michael Sweerts and other Flemish and Dutch baroque painters. A 17th c. empirical solution to mitigate the optical 'simultaneous contrast' effect? Type A1 Journal article
Year 2022 Publication Heritage science Abbreviated Journal
Volume 10 Issue 1 Pages 5
Keywords A1 Journal article; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
Abstract Although the topic is rarely addressed in literature, a significant number of baroque paintings exhibit dark, halo-like shapes around the contours of the dramatis personae. Close examination of both finished and unfinished works suggests that this intriguing feature was a practical tool that helped the artist in the early painting stages. When applying the final brushwork, the halo lost its function, with some artists undertaking efforts to hide it. Although their visibility might not have been intended by the artists, today this dark paint beneath the surface is partially visible through the upper paint layers. Moreover, the disclosure of many halos using infrared photography (IRP), infrared reflectography (IRR) and macro X-ray fluorescence imaging (MA-XRF), additional to those that can be observed visually, suggests that this was a common and established element of 17th-century painting practice in Western Europe. Building on an existing hypothesis, we argue that halos can be considered as a solution to an optical problem that arose when baroque painters reversed the traditional, 15th- and 16th-century painting sequence of working from background to foreground. Instead, they started with the dominant parts of a composition, such as the face of a sitter. In that case, a temporary halo can provide the essential tonal reference to anticipate the chromatic impact of the final dark colored background on the adjacent delicate carnations. In particular, we attempt to clarify the prevalence of dark halos as a response to optical effects such as 'simultaneous contrast' and 'the crispening effect', described in literature only centuries later. As such, the recently termed 'ring condition' can be seen as the present-day equivalent of the 'halo solution' that was seemingly empirically or intuitively developed by 17th-century artists. Modern studies in visual perception proves that by laying a black ring around a target color, the optical impact of a surrounding color can be efficiently neutralized. Finally, by delving into works by Michael Sweerts, it becomes clear that resourceful artists might have adapted the halo technique and the underlying principles to their individual challenges, such as dealing with differently colored grounds.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000739965700001 Publication Date 2022-01-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
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 (down) Most recent IF: 2.5
Call Number UA @ admin @ c:irua:185458 Serial 7217
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Author Cagno, S.; Lind, O.C.; Popic, J.M.; Skipperud, L.; De Nolf, W.; Nuyts, G.; Vanmeert, F.; Jaroszewicz, J.; Janssens, K.; Salbu, B.
Title Micro-analytical characterization of thorium-rich aggregates from Norwegian NORM sites (Fen Complex, Telemark) Type A1 Journal article
Year 2020 Publication Journal Of Environmental Radioactivity Abbreviated Journal J Environ Radioactiv
Volume 219 Issue Pages 106273
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract In this study we performed microscopic characterization of mineral particles that were collected in the thorium-rich Fen Complex in Norway and identified and isolated based on autoradiography in function of their radioactivity. For this we combined information obtained with X-ray absorption mu-CT, mu-XRF and mu-XRD, both in bi- and in three-dimensional (tomographic) mode. We demonstrate that radionuclides and metals are heterogeneously distributed both within soil samples and within individual Th-enriched aggregates, which are characterised as low-density mineral bulk particles with high density material inclusions, where Th as well as several metals are highly concentrated. For these sites, it is important to take into account how these inhomogeneous distributions could affect the overall environmental behaviour of Th and progeny upon weathering due to human or environmental factors. Moreover, the estimated size of the Th-containing inclusions as determined in this work represents information of importance for the characterization of radionuclides and toxic metals exposure, as well as for assessing the viability of mining for Th and rare-earth metals in the Fen Complex and the associated environmental impact.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000535130500005 Publication Date 2020-04-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0265-931x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.3 Times cited Open Access
Notes Approved (down) Most recent IF: 2.3; 2020 IF: 2.31
Call Number UA @ admin @ c:irua:181195 Serial 8229
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Author Lind, O.C.; de Nolf, W.; Janssens, K.; Salbu, B.
Title Micro-analytical characterisation of radioactive heterogeneities in samples from Central Asian TENORM sites Type A1 Journal article
Year 2013 Publication Journal of environmental radioactivity Abbreviated Journal J Environ Radioactiv
Volume 123 Issue Pages 63-70
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract The present work focuses on the use of micro-analytical techniques to demonstrate the heterogeneous distribution of radionuclides and metals in soils collected at Former Soviet Union mining sites in Central Asia. Based on digital autoradiography, radionuclides were heterogeneously distributed in soil samples collected at the abandoned uranium mining sites Kurday, Kazakhstan, Kadji Sai, Kyrgyzstan and Taboshar, Tajikistan. Using electron microscopy interfaced with X-ray microanalysis submicron – mm-sized radioactive particles and rock fragments with U, As, Se and toxic metals on the surfaces were identified in Kurday and Kadji Sai samples. Employing scanning and tomographic (3D) synchrotron radiation based micro-X-ray fluorescence (mu-SRXRF) and synchrotron radiation based micro-X-ray diffraction (mu-SRXRD) allowed us to observe the inner structure of the particles without physical sectioning. The distribution of elements in virtual crosssections demonstrated that U and a series of toxic elements were rather heterogeneously distributed also within individual radioactive TENORM particles. Compared to archived data, U in Kadji Sai particles was present as uraninite (U4O9+y or UO2+x) or Na-zippeite aNa(4)(UO2)(6)[(OH)(10)(SO4)(3)]center dot 4H(2)O), i.e. U minerals with very low solubility. The results suggested that TENORM particles can carry substantial amount of radioactivity, which can be subject to re-suspension, atmospheric transport and water transport. Thus, the potential radioecological and radioanalytical impact of radioactive particles at NORM and TENORM sites worldwide should be taken into account. The present work also demonstrates that radioecological studies should benefit from the use of advanced methods such as synchrotron radiation based techniques. (C) 2012 Elsevier Ltd. All rights reserved.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000321177200007 Publication Date 2012-03-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0265-931x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.31 Times cited 16 Open Access
Notes ; We gratefully acknowledge the support provided by the Norwegian Ministry of Foreign Affairs and the European Commission (HASYLAB proposal I-20070051 EC and II-20090184 EC). The authors are indebted to Dr. Karen Appel and Dr. Manuela Borchert, Hasylab for beamline assistance. ; Approved (down) Most recent IF: 2.31; 2013 IF: 3.571
Call Number UA @ admin @ c:irua:109558 Serial 5710
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Author Lind, O.C.; Salbu, B.; Skipperud, L.; Janssens, K.; Jaroszewicz, J.; de Nolf, W.
Title Solid state speciation and potential bioavailability of depleted uranium particles from Kosovo and Kuwait Type A1 Journal article
Year 2009 Publication Journal of environmental radioactivity Abbreviated Journal J Environ Radioactiv
Volume 100 Issue 4 Pages 301-307
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract A combination of synchrotron radiation based X-ray microscopic techniques (ì-XRF, ì-XANES, ì-XRD) applied on single depleted uranium (DU) particles and semi-bulk leaching experiments has been employed to link the potential bioavailability of DU particles to site-specific particle characteristics. The oxidation states and crystallographic forms of U in DU particles have been determined for individual particles isolated from selected samples collected at different sites in Kosovo and Kuwait that were contaminated by DU ammunition during the 1999 Balkan conflict and the 1991 Gulf war. Furthermore, small soil or sand samples heavily contaminated with DU particles were subjected to simulated gastrointestinal fluid (0.16 M HCl) extractions. Characteristics of DU particles in Kosovo soils collected in 2000 and in Kuwait soils collected in 2002 varied significantly depending on the release scenario and to some extent on weathering conditions. Oxidized U (+6) was determined in large, fragile and bright yellow DU particles released during fire at a DU ammunition storage facility and crystalline phases such as schoepite (UO3·2.25H2O), dehydrated schoepite (UO3·0.75H2O) and metaschoepite (UO3·2.0H2O) were identified. As expected, these DU particles were rapidly dissolved in 0.16 M HCl (84 ± 3% extracted after 2 h) indicating a high degree of potential mobility and bioavailability. In contrast, the 2 h extraction of samples contaminated with DU particles originating either from corrosion of unspent DU penetrators or from impacted DU ammunition appeared to be much slower (2030%) as uranium was less oxidized (+4 to +6). Crystalline phases such as UO2, UC and metallic U or UTi alloy were determined in impacted DU particles from Kosovo and Kuwait, while the UO2,34 phase, only determined in particles from Kosovo, could reflect a more corrosive environment. Although the results are based on a limited number of DU particles, they indicate that the structure and extractability of DU particles released from similar sources (metallic U penetrators) will depend on the release scenarios (fire, impact) and to some extent environmental conditions. However, most of the DU particles (7396%) in all investigated samples were dissolved in 0.16 M HCl after one week indicating that a majority of the DU material is bioaccessible.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000264649500004 Publication Date 2009-02-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0265-931x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.31 Times cited 49 Open Access
Notes Approved (down) Most recent IF: 2.31; 2009 IF: 1.268
Call Number UA @ admin @ c:irua:76413 Serial 5834
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Author Lind, O.C.; Salbu, B.; Janssens, K.; Proost, K.; Dahlgaard, H.
Title Characterization of uranium and plutonium containing particles originating from the nuclear weapons accident in Thule, Greenland, 1968 Type A1 Journal article
Year 2005 Publication Journal of environmental radioactivity Abbreviated Journal J Environ Radioactiv
Volume 81 Issue Pages 21-32
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000228714500003 Publication Date 2005-03-01
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0265-931x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.31 Times cited 37 Open Access
Notes Approved (down) Most recent IF: 2.31; 2005 IF: 1.243
Call Number UA @ admin @ c:irua:52231 Serial 5507
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Author Salbu, B.; Janssens, K.; Lind, O.C.; Proost, K.; Gijsels, L.; Danesi, P.R.
Title Oxidation states of uranium in depleted uranium particles from Kuwait Type A1 Journal article
Year 2004 Publication Journal of environmental radioactivity Abbreviated Journal J Environ Radioactiv
Volume 78 Issue 2 Pages 125-135
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract The oxidation states of uranium in depleted uranium (DU) particles were determined by synchrotron radiation based mu-XANES, applied to individual particles isolated from selected samples collected at different sites in Kuwait. Based on scanning electron microscopy with X-ray microanalysis prior to mu-XANES, DU particles ranging from sub-microns to several hundred micrometers were observed. The.median particle size depended on sources and sampling sites; small-sized particles (median 13 mum) were identified in swipes taken from the inside of DU penetrators holes in tanks and in sandy soil collected below DU penetrators, while larger particles (median 44 mum) were associated with fire in a DU ammunition storage facility. Furthermore, the U-236/U-235 ratios obtained from accelerator mass spectrometry demonstrated that uranium in the DU particles originated from reprocessed fuel (about 10(-2) in DU from the ammunition facility, about 10(-3) for DU in swipes). Compared to well-defined standards, all investigated DU particles were oxidized. Uranium particles collected from swipes were characterized as UO2, U3O8 or a mixture of these oxidized forms, similar to that observed in DU affected areas in Kosovo. Uranium particles formed during fire in the DU ammunition facility were, however, present as oxidation state +5 and +6, with XANES spectra similar to solid uranyl standards. Environmental or health impact assessments for areas affected by DU munitions should therefore take into account the presence of respiratory UO2, U3O8 and even UO3 particles, their corresponding weathering rates and the subsequent mobilisation of U from oxidized DU particles. (C) 2004 Elsevier Ltd. All rights reserved.
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
ISSN 0265-931x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.31 Times cited Open Access
Notes Approved (down) Most recent IF: 2.31; 2004 IF: 1.188
Call Number UA @ admin @ c:irua:49012 Serial 5765
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Author Salbu, B.; Janssens, K.; Lind, O.C.; Proost, K.; Danesi, P.R.
Title Oxidation states of uranium in DU particles from Kosovo Type A1 Journal article
Year 2003 Publication Journal of environmental radioactivity Abbreviated Journal J Environ Radioactiv
Volume 64 Issue Pages 167-173
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000179855200009 Publication Date 2002-12-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0265-931x ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.31 Times cited Open Access
Notes Approved (down) Most recent IF: 2.31; 2003 IF: 0.837
Call Number UA @ admin @ c:irua:39942 Serial 5766
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Author Janssens, K.L.; Partoens, B.; Peeters, F.M.
Title Influence of strain on the magneto-exciton in single and coupled InP/GaInP quantum disks Type A1 Journal article
Year 2004 Publication Physica. E: Low-dimensional systems and nanostructures Abbreviated Journal Physica E
Volume 21 Issue 2/4 Pages 349-353
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher North-Holland Place of Publication Amsterdam Editor
Language Wos 000220873300041 Publication Date 2004-02-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1386-9477; ISBN Additional Links UA library record; WoS full record
Impact Factor 2.221 Times cited Open Access
Notes Approved (down) Most recent IF: 2.221; 2004 IF: 0.898
Call Number UA @ lucian @ c:irua:62428 Serial 1635
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Author Tadić, M.; Peeters, F.M.; Partoens, B.; Janssens, K.L.
Title Electron and hole localization in coupled InP/InGaP self-assembled quantum dots Type A1 Journal article
Year 2002 Publication Physica. E: Low-dimensional systems and nanostructures Abbreviated Journal Physica E
Volume 13 Issue 2/4 Pages 237-240
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher North-Holland Place of Publication Amsterdam Editor
Language Wos 000176869100035 Publication Date 2002-10-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1386-9477; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.221 Times cited 5 Open Access
Notes Approved (down) Most recent IF: 2.221; 2002 IF: 1.107
Call Number UA @ lucian @ c:irua:62427 Serial 905
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Author Mudronja, D.; Vanmeert, F.; Fazinic, S.; Janssens, K.; Tibljas, D.; Desnica, V.
Title Protection of stone monuments using a brushing treatment with ammonium oxalate Type A1 Journal article
Year 2021 Publication Coatings Abbreviated Journal Coatings
Volume 11 Issue 4 Pages 379
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Stone monuments and buildings are susceptible to weathering. Carbonate-based stones are especially vulnerable in acidic environments, whereas magmatic acidic stones are more susceptible to chemical weathering in basic environments. To slow down surface corrosion of limestone and marble artworks/buildings, protective coatings which inhibit calcite dissolution have been proposed. In this work, samples from two stone types with different porosity were treated with ammonium oxalate (AmOx) to create a protective layer of calcium oxalate (CaOx) using the previously developed brushing method. Two different synchrotron microscopy experiments were performed to determine its protective capability. X-ray powder diffraction (SR-mu-XRPD) in transmission geometry allowed visualization of the distributions of calcium carbonate and oxalates along the sample depths. In a second step, X-ray fluorescence (SR-mu-XRF) was used to check the efficiency/integrity of the protective surface coating layer. This was done by measuring the sulfur distribution on the stone surface after exposing the protected stones to sulfuric acid. XRPD showed the formation of a protective oxalate layer with a thickness of 5-15 mu m on the less porous stone, while a 20-30 mu m thick layer formed on the more porous stone. The XRF study showed that the optimal treatment time depends on the stone porosity. Increasing the treatment time from 1 to 3 h resulted in a decreased efficiency of the protective layer for the low porosity stone. We assume that this is due to the formation of vertical channels (cracks) in the protective layer.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000642940900001 Publication Date 2021-03-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2079-6412 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.175 Times cited Open Access OpenAccess
Notes Approved (down) Most recent IF: 2.175
Call Number UA @ admin @ c:irua:178271 Serial 8428
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Author Schalm, O.; Nuyts, G.; Janssens, K.
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
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 (down) Most recent IF: 2.124
Call Number UA @ admin @ c:irua:179835 Serial 8551
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Author Janssens, K.L.; Peeters, F.M.
Title Monte-Carlo simulation of the coherent backscattering of electrons in a ballistic system Type A1 Journal article
Year 1999 Publication Superlattices and microstructures Abbreviated Journal Superlattice Microst
Volume 25 Issue Pages 615-621
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication London Editor
Language Wos 000080373600007 Publication Date 2002-10-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0749-6036; ISBN Additional Links UA library record; WoS full record
Impact Factor 2.123 Times cited Open Access
Notes Approved (down) Most recent IF: 2.123; 1999 IF: 0.649
Call Number UA @ lucian @ c:irua:24169 Serial 2199
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Author Tadić, M.; Peeters, F.M.; Janssens, K.L.; Korkusinski, M.; Hawrylak, P.
Title Strain and band edges in single and coupled cylindrical InAs/GaAs and InP/InGaP self-assembled quantum dots Type A1 Journal article
Year 2002 Publication Journal of applied physics Abbreviated Journal J Appl Phys
Volume 92 Issue 10 Pages 5819-5829
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract A comparative study is made of the strain distribution in cylindrical InAs/GaAs and InP/InGaP self-assembled quantum dots as obtained from isotropic elasticity theory, the anisotropic continuum mechanical model, and from atomistic calculations. For the isotropic case, the recently proposed approach [J. H. Davies, J. Appl. Phys. 84, 1358 (1998)] is used, while the finite-element method, the valence force field method, and Stillinger-Weber potentials are employed to calculate the strain in anisotropic structures. We found that all four methods result in strain distributions of similar shapes, but with notable quantitative differences inside the dot and near the disk-matrix boundary. The variations of the diagonal strains with the height of the quantum dot, with fixed radius, as calculated from all models, are almost linear. Furthermore, the energies of the band edges in the two types of quantum dots are extracted from the multiband effective-mass theory by inserting the strain distributions as obtained by the four models. We demonstrated that all strain models produce effective potentials for the heavy and light holes which agree very well inside the dot. A negligible anisotropy of all normal strains in the (x,y) plane is found, which, providing the axial symmetry of the kinetic part of the multiband effective-mass Hamiltonian, justifies the use of the axial approximation. Strain propagation along the vertical direction is also considered with the aim to study the influence of strain on the electron coupling in stacks of quantum dots. We found that the interaction between the strain fields of the individual quantum dots makes the effective quantum wells for the electrons in the conduction band shallower, thereby counteracting the quantum mechanical coupling. (C) 2002 American Institute of Physics.
Address
Corporate Author Thesis
Publisher American Institute of Physics Place of Publication New York, N.Y. Editor
Language Wos 000178987200036 Publication Date 2002-11-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-8979; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.068 Times cited 73 Open Access
Notes Approved (down) Most recent IF: 2.068; 2002 IF: 2.281
Call Number UA @ lucian @ c:irua:103327 Serial 3164
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Author Cotte, M.; Genty-Vincent, A.; Janssens, K.; Susini, J.
Title Applications of synchrotron X-ray nano-probes in the field of cultural heritage Type A1 Journal article
Year 2018 Publication Comptes rendus : physique Abbreviated Journal Cr Phys
Volume 19 Issue 7 Pages 575-588
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Synchrotron-based techniques are increasingly used in the field of cultural heritage, and this review focuses notably on the application of nano-beams to access high-spatial-resolution information on fragments sampled in historical or model artworks. Depending on the targeted information, various nano-analytical techniques can be applied, providing both identification and localization of the various components. More precisely, nano-X-ray fluorescence probes elements, nano-X-ray diffraction identify crystalline phases, and nano X-ray absorption spectroscopy is sensitive to speciation. Furthermore, computed tomography-based techniques can provide useful information about the morphology and in particular the porosity of materials. (C) 2018 Academie des sciences. Published by Elsevier Masson SAS.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000451631400006 Publication Date 2018-08-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1631-0705; 1878-1535 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.048 Times cited 3 Open Access
Notes ; ; Approved (down) Most recent IF: 2.048
Call Number UA @ admin @ c:irua:156320 Serial 5476
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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.
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
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 (down) Most recent IF: 17.1; 2023 IF: 13.942
Call Number UA @ admin @ c:irua:196061 Serial 8631
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Author Gonzalez, V.; Fazlic, I.; Cotte, M.; Vanmeert, F.; Gestels, A.; De Meyer, S.; Broers, F.; Hermans, J.; van Loon, A.; Janssens, K.; Noble, P.; Keune, K.
Title Lead(II) formate in Rembrandt's Night Watch : detection and distribution from the macro- to the micro-scale Type A1 Journal article
Year 2023 Publication Angewandte Chemie: international edition in English Abbreviated Journal
Volume Issue Pages 1-9
Keywords A1 Journal article; Art; Antwerp X-ray Imaging and Spectroscopy (AXIS)
Abstract The Night Watch, painted in 1642 and on view in the Rijksmuseum in Amsterdam, is considered Rembrandt's most famous work. X-ray powder diffraction (XRPD) mapping at multiple length scales revealed the unusual presence of lead(II) formate, Pb(HCOO)(2), in several areas of the painting. Until now, this compound was never reported in historical oil paints. In order to get insights into this phenomenon, one possible chemical pathway was explored thanks to the preparation and micro-analysis of model oil paint media prepared by heating linseed oil and lead(II) oxide (PbO) drier as described in 17(th) century recipes. Synchrotron radiation based micro-XRPD (SR-mu-XRPD) and infrared microscopy were combined to identify and map at the micro-scale various neo-formed lead-based compounds in these model samples. Both lead(II) formate and lead(II) formate hydroxide Pb(HCOO)(OH) were detected and mapped, providing new clues regarding the reactivity of lead driers in oil matrices in historical paintings.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000920584500001 Publication Date 2023-01-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1433-7851; 0570-0833 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 16.6 Times cited Open Access OpenAccess
Notes Approved (down) Most recent IF: 16.6; 2023 IF: 11.994
Call Number UA @ admin @ c:irua:194279 Serial 7318
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Author Dooley, K.A.; Chieli, A.; Romani, A.; Legrand, S.; Miliani, C.; Janssens, K.; Delaney, J.K.
Title Molecular fluorescence imaging spectroscopy for mapping low concentrations of red lake pigments : Van Gogh's painting The Olive Orchard Type A1 Journal article
Year 2020 Publication Angewandte Chemie-International Edition Abbreviated Journal Angew Chem Int Edit
Volume Issue Pages
Keywords A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Abstract Vincent van Gogh used fugitive red lake pigments that have faded in some paintings. Mapping their distribution is key to understanding how his paintings have changed with time. While red lake pigments can be identified from microsamples, in situ identification and mapping remain challenging. This paper explores the ability of molecular fluorescence imaging spectroscopy to identify and, more importantly, map residual non-degraded red lakes. The high sensitivity of this method enabled identification of the emission spectra of eosin (tetrabromine fluorescein) lake mixed with lead or zinc white at lower concentrations than elemental X-ray fluorescence (XRF) spectroscopy used on account of bromine. The molecular fluorescence mapping of residual eosin and two carmine red lakes in van Gogh's The Olive Orchard is demonstrated and compared with XRF imaging spectroscopy. The red lakes are consistent with the composition of paint tubes known to have been used by van Gogh.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000512477200001 Publication Date 2020-01-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1433-7851; 0570-0833 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 16.6 Times cited 2 Open Access
Notes ; We thank Damon Conover and Roxanne Radpour for help with the fluorescence self-absorption correction, and Ella Hendricks for discussions about van Gogh~s letters and materials. K.J. and S.L. thank the Research Council of the University of Antwerp for financial support (ID grant 25805 to S.L. and GOA project SolarPaint). Also FWO, Brussels provided financial support (grants G056619N and G054719N). The European research project IPERION-CH, funded by the European Commission, H2020-INFRAIA-2014-2015 (Grant agreement n. 654028) is also acknowledged. ; Approved (down) Most recent IF: 16.6; 2020 IF: 11.994
Call Number UA @ admin @ c:irua:166490 Serial 6563
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Author Broers, F.T.H.; Janssens, K.; Weker, J.N.; Webb, S.M.; Mehta, A.; Meirer, F.; Keune, K.
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
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 (down) Most recent IF: 15; 2023 IF: 13.858
Call Number UA @ admin @ c:irua:196762 Serial 8948
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