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Fremout W.,Royal Institute for Cultural Heritage KIK IRPA | Fremout W.,Ghent University | Kuckova S.,Charles University | Kuckova S.,Institute of Chemical Technology Prague | And 7 more authors.
Rapid Communications in Mass Spectrometry | Year: 2011

Proteomics techniques are increasingly applied for the identification of protein binders in historical paints. The complex nature of paint samples, with different kinds of pigments mixed into, and degradation by long term exposure to light, humidity and temperature variations, requires solid analysis and interpretation methods. In this study matrix-assisted laser desorption/ ionisation time-of-flight (MALDI-TOF) mass spectra of tryptic-digested paint replicas are subjected to principal component analysis (PCA) and soft independent modelling of class analogy (SIMCA) in order to distinguish proteinaceous binders based on animal glues, egg white, egg yolk and milk casein from each other. The most meaningful peptide peaks for a given protein class will be determined, and if possible, annotated with their corresponding amino acid sequence. The methodology was subsequently applied on egg temperas, as well as on animal glues from different species. In the latter small differences in the MALDI-TOF mass spectra can allow the determination of a mammal or sturgeon origin of the glue. Finally, paint samples from the 16 th century altarpiece of St Margaret of Antioch (Mlynica, Slovakia) were analysed. Several expected peaks are either present in lower abundance or completely missing in these natural aged paints, due to degradation of the paints. In spite of this mammalian glue was identified in the St Margaret samples. © 2011 John Wiley & Sons, Ltd.


Fremout W.,Royal Institute for Cultural Heritage KIK IRPA | Fremout W.,Ghent University | Dhaenens M.,Ghent University | Saverwyns S.,Royal Institute for Cultural Heritage KIK IRPA | And 4 more authors.
Analytica Chimica Acta | Year: 2010

A proteomics approach was used for the identification of protein binders in historical paints: the proteins were digested enzymatically into peptides using trypsin before being separated and detected by high performance liquid chromatography-electrospray ionisation tandem mass spectrometry (HPLC-ESI-MS/MS). Mascot (Matrix Science) was used to analyse the resulting data and for protein identification. In contrast to amino acid analysis, amino acid sequences could be studied that retain much more information about the proteins. The best extraction strategy was selected based on the number of peptides that were identified in the protein content of paint replicas using different methods. The influence of pigments on the extraction method was studied and the analytical characteristics of the selected method were determined. Finally this method was applied to historical paint microsamples on the anonymous early 15th century panel painting Crucifixion with St Catherine and St Barbara (Calvary of the Tanners), the St Catherine Altarpiece by Joes Beyaert (c. 1479) and two paintings by Pieter Brueghel the Younger (1617-1628). © 2009 Elsevier B.V. All rights reserved.


Fremout W.,Royal Institute for Cultural Heritage KIK IRPA | Fremout W.,Ghent University | Dhaenens M.,Ghent University | Saverwyns S.,Royal Institute for Cultural Heritage KIK IRPA | And 4 more authors.
Analytica Chimica Acta | Year: 2012

In recent years, the use of liquid chromatography tandem mass spectrometry (LC-MS/MS) on tryptic digests of cultural heritage objects has attracted much attention. It allows for unambiguous identification of peptides and proteins, and even in complex mixtures species-specific identification becomes feasible with minimal sample consumption. Determination of the peptides is commonly based on theoretical cleavage of known protein sequences and on comparison of the expected peptide fragments with those found in the MS/MS spectra. In this approach, complex computer programs, such as Mascot, perform well identifying known proteins, but fail when protein sequences are unknown or incomplete. Often, when trying to distinguish evolutionarily well preserved collagens of different species, Mascot lacks the required specificity. Complementary and often more accurate information on the proteins can be obtained using a reference library of MS/MS spectra of species-specific peptides. Therefore, a library dedicated to various sources of proteins in works of art was set up, with an initial focus on collagen rich materials. This paper discusses the construction and the advantages of this spectral library for conservation science, and its application on a number of samples from historical works of art. © 2012 Elsevier B.V.


Linnow K.,University of Hamburg | Steiger M.,University of Hamburg | Lemster C.,University of Hamburg | De Clercq H.,Royal Institute for Cultural Heritage KIK IRPA | Jovanovic M.,Royal Institute for Cultural Heritage KIK IRPA
Environmental Earth Sciences | Year: 2013

Several double salts have been detected in building materials and most of these salts are incongruently soluble compounds. In contrast to single salts, however, no systematic investigations of the crystallization behavior and deleterious effects of incongruently soluble double salts exist. To assess the damage potential of these salts, a systematic investigation of their highly complex behavior is desirable. This paper deals with the crystallization behavior of various solids in the ternary mixed NaNO3-Na2SO4 system including the formation of the double salt darapskite, Na3NO3SO4·H2O. The crystallization sequence during droplet evaporation experiments at room conditions was determined using Raman and polarization microscopy. The basic idea of this research is to use deviations of the crystallization sequence of a salt or a mixed salt solution from the equilibrium pathway as an indicator to detect the degree of supersaturation. The observed crystallization pathway includes the formation of the metastable phases Na2SO4(III), Na2SO4(V) and darapskite. The experimental observations are discussed on the basis of the NaNO3-Na2SO4-H2O phase diagram and the results provide evidence for crystal growth from highly supersaturated solutions in both systems. If the crystals growing under these conditions are confined, these supersaturations result in substantial crystallization pressures. © 2012 Springer-Verlag Berlin Heidelberg.


De Clercq H.,Royal Institute for Cultural Heritage KIK IRPA | Jovanovic M.,Royal Institute for Cultural Heritage KIK IRPA | Linnow K.,University of Hamburg | Steiger M.,University of Hamburg
Environmental Earth Sciences | Year: 2013

The behaviour of two types of limestones having a different porosity, Maastricht and Euville limestone, laden with aqueous solutions of equimolar mixtures of sodium sulphate/sodium nitrate or sodium sulphate/potassium sulphate was investigated. At 50 % RH, the efflorescences on Maastricht samples during the first 30 h of drying consisted of similar amounts of thenardite and darapskite in case of an equimolar mixture of sodium sulphate/sodium nitrate while those on Euville samples under the same conditions contained mainly darapskite. After drying at 20 °C and 85 % RH, thenardite, formed through the precipitation and dehydration of mirabilite, was mostly detected in the efflorescences on both Maastricht and Euville samples. Re-wetting by increasing the RH from 50 to 85 % resulted in substantial damage on Maastricht stone laden with an equimolar mixture of sodium sulphate/sodium nitrate as a consequence of high supersaturation of mirabilite. In case of a contamination with equimolar amounts of sodium sulphate and potassium sulphate, the efflorescence on both limestones during drying at 50 % RH contained predominantly aphthitalite. The observed crystallisation behaviour is compared to the theoretical behaviour. The results indicate a strong influence of stone properties on the crystallisation behaviour of salt mixtures. © 2012 Springer-Verlag Berlin Heidelberg.


Fontaine L.,Royal Institute for Cultural Heritage KIK IRPA | Hendrickx R.,Royal Institute for Cultural Heritage KIK IRPA | De Clercq H.,Royal Institute for Cultural Heritage KIK IRPA
Environmental Earth Sciences | Year: 2015

Tournai stone has been extensively used in Western European historical architecture and is subjected to severe deterioration mechanisms, which were investigated in two Romanesque portals of the cathedral of Tournai city. The stone material was studied with thin-section petrography and SEM-EDX and its hygric, hydric and thermal properties were measured. The porosity is very low and the pore size distribution can be related to either typical pores associated with the clay fraction or with micro-cracks. The formation and propagation of cracks are related to anisotropy of the stone (clay presence in laminae with a preferred direction) and the influence of different external climatic factors. As expected, the effect of liquid water has the highest damage potential while the clay fraction imparts a pronounced hygroscopic behaviour to the stone. The identified clay mineral was illite. Although its non-swelling properties exclude interlayer swelling as a cause of damage, interparticular osmotic pressure is recognized as the most plausible damage cause at the micro-scale. Gypsum crusts occur in two morphologies: films and thick deposits, both showing a comparable layered structure, but significantly differing in the proceeding process and shapes and features. Due to the nature of the stone and of the damage processes, feasible measures for preventive conservation on the long term are to be found in the direction of decreasing the climatic influence by means of sheltering. © 2015, Springer-Verlag Berlin Heidelberg.


Fremout W.,Royal Institute for Cultural Heritage KIK IRPA | Saverwyns S.,Royal Institute for Cultural Heritage KIK IRPA
Journal of Raman Spectroscopy | Year: 2012

Identification of pigments in modern and contemporary arts is indispensable to determine correct conservation strategies, to study degradation processes and to answer authenticity-related questions. Since the early 20th century, the introduction of synthetic organic pigments (SOPs) has enormously increased the number of available pigments. Micro-Raman spectroscopy has proven to be the first line technique for the identification of these pigments, which often only show small variations on the same basic chemical structures. To ensure a correct identification, however, an as complete as possible library of reference spectra is needed. Although reference spectra of SOPs have been published before, they have always been limited to a certain number of pigments. Some publications discuss only one or a few chemical classes, and others are limited to a certain number of pigments belonging to different classes; none, however, have attempted to create an extensive library of commercially available pigments. Moreover, most of the reference spectra published so far are only available as small imprints or as peak lists and, as such, hardly usable for spectral matching algorithms. Often, flow charts have been developed on the basis of the pigments studied, to help in identifying unknown SOPs. In this paper, a digital spectral library that comprehends almost 300 spectra of different SOPs is presented. The library was tested by means of non-invasive analysis of four contemporary paintings from the collections of the Stedelijk Museum voor Actuele Kunst (Ghent, Belgium). Published flow charts have been evaluated in relation to digital search algorithms by using the extensive library of SOPs. To enable fellow research and conservation institutes to make use of these data, the nearly 300 reference spectra of synthetic organic pigments are available in digital format on http://modern.kikirpa.be. Copyright © 2012 John Wiley & Sons, Ltd.


De Clercq H.,Royal Institute for Cultural Heritage KIK IRPA | Godts S.,Royal Institute for Cultural Heritage KIK IRPA
Applied Physics A: Materials Science and Processing | Year: 2016

The rehabilitation of historic buildings is a practice that aims to turn a historic property into a state of contemporary comfort for private or commercial use, while preserving its historic, architectural and cultural value, respecting items of authenticity, compatibility and sustainability. What once was a modest use of locally fired brick and mortar has become the subject of ambitious rehabilitation campaigns conforming to the rules of comfort and hygiene of the twenty-first century. A pre-investigation concerning the diagnosis of damage phenomena and the risk assessment of interventions is a crucial aspect for the success of a restoration campaign. The question of “How to optimally preserve a monument within its current conditions” is replaced by “How can a monument optimally perform in the conditions suited to the assigned rehabilitation project”. Today historic farms and their surroundings, after being abandoned for several decades, are the subject of different types of private or commercial rehabilitation projects. An example of such a project is the farm “Hof De Pleyne” in Loppem (West-Flanders, Belgium). The project intended to integrate a restaurant kitchen into the former animal barn. The limits of salt content with respect to the desired rehabilitation facilities while respecting safety regulations are presented. © 2016, Springer-Verlag Berlin Heidelberg.


Hendrickx R.,Royal Institute for Cultural Heritage KIK IRPA | De Clercq H.,Royal Institute for Cultural Heritage KIK IRPA | Hayen R.,Royal Institute for Cultural Heritage KIK IRPA
International Journal of Architectural Heritage | Year: 2016

Salt-accumulating renders are usually applied in several layers with different specific properties of moisture transport. An extensive experimental programme was carried out to establish a relationship between those properties of individual layers and the performance of combined systems on a salt-laden substrate. Each of the 20 renders was characterized separately in absorption and drying tests, vacuum saturation tests, dry cup tests, mercury intrusion porosimetry, and ultrasound wave velocity measurements. Each of the 12 combined render systems was applied on a brick, which was then saturated with a concentrated NaCl solution by free capillary uptake. Subsequently the assembly was closed at the bottom and subjected to an accelerated drying test (50° C and 15% relative humidity). Moisture and salt profiles over the depth were taken regularly during 1 month. The results reveal very different degrees of effectiveness and levels of risk for the substrate, which are related to the moisture transport properties. © 2016 Taylor & Francis.


Hendrickx R.,Royal Institute for Cultural Heritage KIK IRPA
Materials and Structures/Materiaux et Constructions | Year: 2013

Over the last decades the Karsten tube has been used as a versatile testing device to measure the water absorption of porous walls. It is non-destructive and it can give reproducible results when used accurately. A major drawback however is the lack of a physical interpretation of the results. This paper uses analytical models and a numerical simulation in 3D to allow a more fundamental and general interpretation of the test results. A relatively simple model for a soil infiltrometer test was proven to give a good fit to experimental field data and to lab test results. 3D numerical simulations, performed with Delphin 5 software, provide extra insight about the correctness of the model assumptions of a sharp front process and a simplified shape of the wetting front. A supplementary measurement of the increase of the diameter of the wetted zone during the test allows a straightforward calculation of the capillary saturated moisture content and the sorptivity of the material. Moreover an analytical relation is presented between the results of the Karsten test as described in the old standards and the sorptivity. © 2012 RILEM.

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