Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2012
Forfattere
Lone Ross Gobakken Olav Albert HøibøSammendrag
The aesthetic service life of outdoor exposed wooden surfaces are often decided by growth of moulds and blue stain fungi, but also other visual changes caused by weathering such as colour changes, abrasion or wear, blistering, flaking, and even cracks in the wood or coating will contribute. When developing models that describe changes in the wood material and aim to predict the service life, it is essential to understand the impact of different climatic factors, the effect of variation in the wooden product itself and in the quality of craftsmanship and building design. The objective of this presentation is to gather knowledge about which factors influence surface mould growth on wood substrates in an outdoor environment. The analysis and the model development are based on data from evaluation of mould growth coverage on outdoors exposed wood panels consisting of different combinations of wood substrates and surface finishes from a number of field studies performed over the last years [1, 2, 3, 4, 5, 6 and 7].
Forfattere
Peder GjerdrumSammendrag
Sawmillers want to have predictable and homogeneous timber outcome from their industry. This paper analyses and discusses how well timber quality of boards from the same log, and in particular pairs of sister boards, correspond to each other, i.e. the limit for quality homogeneity.Observations from three different sawn timber outcome experiments were analysed. Varying quality traits were observed: appearance and machine strength grading, knot size and number, and board value.The results showed that 80% and 53% respectively, for two different samples, of the boards had different quality grade from their sister boards, and less homogeneity when more boards are sawn from the same log. The correlation between observations made in sister boards were modestly 0.42 for biggest green knot diameter, and almost absent for dry knots and other traits. Board value and machine strength are better correlated, 0.76 and 0.69, respectively.Relative pairwise difference for these parameters was found to follow the exponential distribution with mean 0.169 and 0.068, respectively. The results clearly indicate that there is no easy way achieving a consistent and pre-requested quality, at the same time avoiding an inherent portion of diverted quality boards.
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From the range of information published, acetylation appears well suited to provide adequate protection against biological attack for materials derived from typically non-durable wood species. Acetylated wood is now commercially available both in Europe and in the USA. But still there are a lot of unanswered questions related to fungal decay mechanisms in acetylated wood.The paper summarize existing knowledge and highlight future research opportunities related to fungal deterioration of acetic anhydride modified wood. In addition statistical analyses based on previously published data were performed to quantify what factors contribute most to the performance (calculated as test sample/control).The results showed that WPG can explain approximately 50 % of the performance, measured as test sample/control (T/C), for acetic anhydride treated wood. Other of the applied variables, like wood species or type of fungus can reduce the variance in T/C by additional 15 %.