Guro Hjulstad

• Braovac, Susan; Hjulstad, Guro & Storbekk, Elin Christine (2012). Decisions about moving collections – where do conservators fit in? How can we contribute? I Bronken, Ida Antonia Tank; Braovac, Susan; Olstad, Tone Marie & Ørnhøi, Anne Apalnes (Red.), Moving Collections. Processes and Consequences. Archetype Publications Ltd.. ISSN 9781904982845. s. 175–184. Fulltekst i vitenarkiv

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• Braovac, Susan; Jensen, Maria; Aarseth, Bjarte Einar; Bill, Jan; Hjulstad, Guro & Løchen, Ragnar [Vis alle 9 forfattere av denne artikkelen] (2011). Long term responses in archaeological wood to ambient temperature and relative humidity – case study: the Oseberg Ship. Fulltekst i vitenarkiv Vis sammendrag

  INTRODUCTION The Oseberg ship, dated from ca 815-820 AD, is one of the most important discoveries of the Viking age period in Norway. The fact that the ship consists of 90 % original material makes it a unique find with no comparison elsewhere in the world. The ship is 21.5 meters long, built with radially cut, 3 cm thick oak planks and is 5 meters at its widest. In 1904 the waterlogged wood was conserved with linseed oil and creosote and the surface exterior was then lacquered. Over 2000 pieces were used for the reconstruction of the ship with the use of both original and modern screws together with adhesive. The Oseberg ship, displayed at the Viking Ship Museum in Oslo, has been subjected to an uncontrolled climate since 1926, with only heating in winter. The display area is therefore influenced by seasonal changes in relative humidity (RH), which rises above values of 70% RH in summer, and drops below 30% RH in winter. Rapid changes over the course of a few hours have also been recorded. EXPERIMENTAL RESULTS Continuous monitoring of dimensional change due to RH fluctuations has been carried out on two planks of the ship and on two samples free to warp. To our knowledge, it is the first example of long term hygro-mechanical monitoring on an archaeological wooden artifact. Through this approach it is possible to show the specific sensitivity to RH fluctuations; restrained planks show the least response, while unrestrained samples have highest response to RH changes. The analysis of the data obtained after fifteen months of continuous logging allows us to quantify the specific “sensitivity” of the wood, which can be useful in determining the threshold of allowable RH fluctuations. The results of stress on the free samples in the exhibition site will be discussed. It is also planned to measure the forces absorbed by the restrained samples so that long-term mechanical effects of absorbed stress can be understood better. These data are fundamental as a validation of future Finite Element simulations and hygromechanical modelling of deteriorated wood.

• Vici, Paolo Dionisi; Aarseth, Bjarte Einar; Bill, Jan; Hjulstad, Guro; Jensen, Maria Malherbes & Løchen, Ragnar [Vis alle 9 forfattere av denne artikkelen] (2009). In-situ deformation measurements on a large wooden archaeological artefact: the Viking Age Oseberg ship. Fulltekst i vitenarkiv
• Storbekk, Elin Christine & Hjulstad, Guro (2008). Is this the way to treat an Old lady? Fulltekst i vitenarkiv

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