This project focuses on innovative biological methods of extraction for the preservation of waterlogged wood suffering from salt precipitation and acidification. The principal investigator and her ...team proposed to exploit biomineralization capacities of some bacteria for anticipating the extraction of iron and sulfur compounds when wood is still wet. A comprehensive assessment of the extraction performances achieved on wood objects from lake and marine environments will allow a versatile extraction method to be proposed to end-users.
Wood is a complex hierarchical material. As a widely available renewable resource, it has been used throughout history to construct dwellings and transportation, tools, art and funerary objects. The ...desire to better understand cultural heritage and preserve it for future generations has long been a major driver in the study of wooden objects in the social sciences. This trend can also be associated with a recent strong push to create, low-cost, environmentally-responsible, sustainable housing solutions for rapidly expanding urban populations. Thus, interest in studying wood degradation and conservation from an engineering/materials science perspective has increased significantly. The study of degradation phenomena in wooden artefacts, along with methods to conserve or enhance their material properties and monitor changes over time is, not only, invaluable to archaeological science, but also to engineers and materials scientists concerned with the endurance of the wooden constructions of tomorrow. The aim of this review is to highlight recent developments in the characterisation, consolidation and monitoring of materials properties of archaeological wood. A specific focus will be placed on bio-sourced consolidants and multi-phase systems based on nano-fillers, recognising the contribution to archaeological science and underlining the impact this knowledge can play on future developments in wooden construction.
This book is a selection of manuscripts devoted to the conservation and preservation of wooden cultural heritage. The articles present the new methods for conservation of various historical wooden ...artefacts, reliable modern techniques for characterisation of the wood structure, properties and degree of degradation, and discusses problems and doubts related to all aspects of conservation and re-conservation of wooden cultural heritage. It contains both review and research papers to give the readers a broader picture of the problems and issues related to the conservation of wooden historical objects and structures. We need to remember that wooden cultural heritage is an integral part of our culture and history that define our humanity. We are obliged to protect it, save it from oblivion, and preserve it for future generations.
Wood has been extensively used as a material for different applications over the years, therefore the understanding of different degradation processes in various environments is of great importance. ...In this study, the infrared spectroscopy, X-ray diffraction and chemometric methods were used to evaluate and compare the structure of archaeological and artificially degraded oak wood. The results clearly show that modifications in the structure of archaeological wood are related to the position of the material in the log (sapwood and heartwood), thus the extent of wood degradation. To identify the possible factors influencing these effects, the control wood samples were exposed to artificial white rot biodegradation with Coriolus (Trametes) versicolor and to alkali treatment (with NaOH solution). Due to the structural similarities between biodegraded wood and control or archaeological samples, this type of decay is likely to occur during natural ageing along with degradation produced by other environmental factors. Further, no real similarity was identified between the alkali treated wood and archaeological samples, indicating that such degradation does not affect wood under natural conditions.
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•Archaeological waterlogged and artificially degraded wood samples were analysed.•FT-IR spectroscopy, X-ray diffraction and chemometric methods were used to evaluate wood structure.•Structural modification of archaeological wood was related to its initial structure.•Differences between sapwood and heartwood of archaeological samples were observed.•Excessive depletion of carbohydrates was observed for sapwood archaeological sample.
Many buildings in Egypt e.g. museums, mosques and churches, do not possess controlled environments for minimizing the risks of damage of wooden artifacts due to the growth of fungi. Fungal damage ...usually appears as change in wood color, appearance of stains, and sometimes deformation of wooden surfaces. In this study we focused on the effect that some fungi exert on the properties of wooden artifacts and evaluated the effectiveness of different concentrations of chitosan on their protection against damage by mold fungi.
Samples were collected from different monuments and environments, and fungi growing on them were isolated and identified. The isolated Penicillium chrysogenum, Aspergillus flavus and Aspergillus niger strains were used for the infestation of new pitch pine samples. The results revealed that the lightness of samples infected with any of the tested fungi decreased with increasing incubation times. XRD analysis showed that the crystallinity of incubated samples treated individually with the different concentrations of chitosan was lower than the crystallinity of infected samples. The crystallinity index measured by the first and the second method decreased after the first and second months but increased after the third and fourth months. This may due to the reducing of amorphous part by enzymes or acids produced by fungi in wooden samples.
The growth of fungi on the treated wood samples decreased with increasing the concentration of chitosan. Hence, it was demonstrated that chitosan prevented fungal growth, and its use could be recommended for the protection of archeological wooden artifacts.
•Waterlogged archaeological wood was modeled from fresh balsa wood.•One-week immersion in deionized water under vacuum is necessary to afterwards degrade the wood.•Iron sulfides were successfully ...formed through selected impregnation protocols.•Chemometrics approach allowed to validate spectroscopies analyses.
Reduced iron and sulfur species accumulated within waterlogged archaeological wood artefacts during their burial time. Oxygen exposure of the artefacts during recovery leads to acidification and salts precipitation, which causes irreversible physical and chemical damages. Prior to accurately evaluating novel extraction methods, the procedures for creating analogous samples were evaluated for efficacy. Waterlogged wood analogues provide access to a whole set of homogeneous and sacrificial samples that replicate characteristics of waterlogged archaeological wood in terms of content degradation and the presence of reduced iron and sulfur species. In this study, we evaluated the preparation of model samples from fresh balsa wood artificially contaminated with reduced iron and sulfur species. Wood degradation and the formation of reduced iron and sulfur species were assessed by Fourier Transformed Infrared (FTIR) and Raman spectroscopies and validated through statistic methods, such as Principal Component Analysis (PCA). Among the three impregnation protocols investigated, one method appeared to be the most effective in term of iron sulfide formation, especially partially oxidized mackinawite Fe1-xS. The selected protocol proved reproducible and efficient on both fresh balsa and Neolithic oak samples. From these observations confirmed by the PCA analyses on spectroscopic dataset, a suitable method to model waterlogged archaeological wood was established.
In this study, samples were collected from various ancient wooden shipwrecks, including the Shinan shipwreck and Jindo shipwreck that used iron nails, the Yeongheungdo shipwreck carrying iron ...artifacts, as well as the Sibidongpado shipwreck and Wando shipwreck where degradation products were not observed, all of which were salvaged by the National Research Institute of Maritime Heritage. The aim was to analyze the characteristics of degradation products generated by iron (Fe) within the salvaged wooden shipwreck materials and establish fundamental data on degradation products in waterlogged archaeological wood. The analysis revealed that sulfur (S) is generally accumulated in wood obtained from marine environments. It was observed that the content of inorganic substances such as iron and sulfur was significantly higher in the Shinan shipwreck, Jindo shipwreck, and Yeongheungdo shipwreck compared to Sibidongpado shipwreck and Wando shipwreck, which used wooden nails. This indicates that the presence of iron affects the accumulation of degradation products and suggests that iron is a factor in the corrosion of wood. Furthermore, crystallin compounds were observed within the cell walls, and higher concentrations of iron and sulfur were found in the resin ducts, rays, and radial tissues. This suggests that during desalination and consolidation treatments, warm water or polyethylene glycol (PEG) may move degradation factors into resincanals, rays, radial tissues, etc.
The Oseberg collection includes the most complete ensemble of wooden remains from the Viking Age. However, since many of the wooden objects were treated with alum in the early 1900s, they now suffer ...from dramatic conservation issues.
A multi-analytical approach was adopted to investigate both the organic and the inorganic components of some selected wood fragments, with the aim of fully characterising the materials and their decomposition products. A particular focus was taken on the differences between the surface and the core of the fragments analysed, and on the correlations between the results obtained by the different techniques, in order to disclose possible interactions between the materials during degradation. In addition to differences in alum concentration and wood alteration between the surface and the core, some decomposition/transformation products of alum, such as mercallite (KHSO4), were identified by FTIR and XRD. Contextual interpretation of the results obtained by ICP-OES elemental analysis of inorganic components and Py(HMDS)-GC/MS characterisation of degraded lignocellulosic materials supported some previous observations about potential relationships between specific metals (Al, Fe, Ca) and wood degradation and enabled new correlations to be highlighted.
Although similar degradation patterns were revealed in the investigated objects–depletion of holocellulose, oxidation of lignin and some transformation of alum - a notable variability at the molecular level was highlighted. This is an important factor to be taken into account for the planning of re-treatment strategies of these extremely precious artefacts.
•Archaeological alum-treated wood samples from the Oseberg collection were analysed.•Extensive degradation of holocellulose and oxidation of lignin were observed.•Potassium bisulphate was observed as a decomposition product of alum.•A large amount of sulphates likely come from sulphuric acid formed by alum treatment.•Correlations between lignin oxidation and K/Al/S/Fe/Ca contents were observed.
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