Polysaccharide degradation in waterlogged oak wood from the ancient warship Vasa

Lindfors, Eva-Lisa; Lindström, Mikael; Iversen, Tommy

doi:10.1515/hf.2008.008

Cited by 34 publications

(44 citation statements)

References 10 publications

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“…The hemicelluloses are continuously degraded as acidic groups split off and cause further in-situ acid hydrolysis [23]. Similar phenomena have been reported earlier [7,24].…”

Section: Degree Of Degradation Prior To Ammonia Treatmentsupporting

confidence: 56%

The Effects of the Ammonia Neutralizing Treatment on Marine ArchaeologicalVasaWood

Fors¹,

Richards²

2010

Studies in Conservation

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“…The hemicelluloses are continuously degraded as acidic groups split off and cause further in-situ acid hydrolysis [23]. Similar phenomena have been reported earlier [7,24].…”

Section: Degree Of Degradation Prior To Ammonia Treatmentsupporting

confidence: 56%

The Effects of the Ammonia Neutralizing Treatment on Marine ArchaeologicalVasaWood

Fors¹,

Richards²

2010

Studies in Conservation

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“…The state of conservation of Vasa is a complex equilibrium between the chemical modification occurred under the waterlogged conditions and the consolidation treatments to which it has been subjected. It was recognized that the sulfuric acid, generated by oxidation of the sulfur produced by the sulfate-reducing bacteria, (ubiquitous in the near anoxic conditions on the Vasa shipwreck site) could be the main threat to the longevity of the treated Vasa timbers [16][17][18][19]. This assumption might be important with respect to the degradation of polysaccharides in the bacterially degraded surface regions, however, in the interior of the wood, other processes related to iron catalyzed degradation and increased acidity due to low molecular organic acids are possibly more important [20,21].…”

Section: Introductionmentioning

confidence: 99%

Chemical characterization of archaeological wood: Softwood Vasa and hardwood Riksapplet case studies

Zoia¹,

Salanti²,

Orlandi³

2015

Journal of Cultural Heritage

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“…The density of both Vasa oak and reference oak will be measured from volume-weight measurements and compared with X-ray measurements. The PEG content can be determined using methods such as Soxhlet extraction, nuclear magnetic resonance spectroscopy (NMR) or matrix-assisted laser desorption/ ionisation time-of-flight (MALDI-TOF) mass spectrometry [3,25,37].…”

Section: Relationship Between Density Moe and Peg Distributionmentioning

confidence: 99%

Strategy for developing a future support system for the Vasa warship and evaluating its mechanical properties

2013

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To maintain the integrity of the Vasa warship after salvage in 1961, conservation treatment with polyethylene glycol was carried out to prevent the collapse of cell walls. This treatment had negative effects on the strength and stiffness of the oak and the hull structure has been found to slowly deform over time. It is of interest to construct a three-dimensional numerical computer model to model and predict the deformation of the warship. This creates difficulties related to the complexity of measuring the detailed material properties that are required as input. In this context, a non-destructive methodology to predict the stiffness of the Vasa oak in terms of moduli of elasticity in the three principal directions of timber at critical positions in the ship would be useful. The twofold aim of the paper is to propose a strategy for a support system and to conduct an on-site assessment of the warship to predict the mechanical properties of the Vasa oak material. This paper also contains an up-to-date review of all essential mechanical data measured on the Vasa oak. The preliminary investigation using an X-ray technique to investigate the density properties produced promising results for future use in the evaluation of the mechanical performance. Based on these results, a procedure to establish the stiffness properties of the Vasa oak in terms of MOE was suggested, using a combination of data from previous measurements, in combination with extended tests on Vasa oak specimens and an X-ray-based density calibration procedure. The general complexity of the Vasa warship can be mainly attributed to large variations in the properties of Vasa oak due to surface degradation, chemical treatment and the disintegration of the cell-wall structure originating from centuries of waterlogged conditions. That causes difficulties when assessing mechanical and physical properties on a structural level. A combination of visual inspection together with X-ray investigation is of great importance to evaluate those properties and to obtain more accurate estimates. The results from evaluating mechanical properties can serve as input in a numerical model and serve as a foundation for decision-making relating to the modification of the support system.

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Polysaccharide degradation in waterlogged oak wood from the ancient warship Vasa

Cited by 34 publications

References 10 publications

The Effects of the Ammonia Neutralizing Treatment on Marine ArchaeologicalVasaWood

The Effects of the Ammonia Neutralizing Treatment on Marine ArchaeologicalVasaWood

Chemical characterization of archaeological wood: Softwood Vasa and hardwood Riksapplet case studies

Strategy for developing a future support system for the Vasa warship and evaluating its mechanical properties

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