Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2003
Authors
Ali Temiz Morten Eikenes U.C. Yildiz Fred G. Evans Bjørn JacobsenAbstract
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Authors
Roger A. SedjoAbstract
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Authors
Peder GjerdrumAbstract
Artikkelen omhandler forsøksopplegg og reslultater av forsøk med 1) små feilfri prøver tørket ved temperaturer 30 - 60 - 90 - 120 grader og 2) prøver av varierende lengde/kvalitet av vanlig, industrielt fremstilt trelast av gran. For trelast tørket ved temperatur opp til 60-75 grader er det liten endring av likevektsfuktigheten (LVF) og i hysterese, med økende effekt for høyere tørketemperatur. LVF ble funnet å øke proporsjonalt med logaritmen av prøvens lengde, og slik at prøver med kvist mv. har 0.4 %-enh. lavere LVF enn feilfri prøver av samme lengde. Også hysteresis øket med økende lengde. Ettersom bare en begrenset del av området for faktorer som påvirker LVF og hysterese er undersøkt, bør undersøkelsene fortsette.
Authors
Per Otto Flæte Erlend Ystrøm HaartveitAbstract
For manufacturing of naturally durable products of Scots pine it is crucial to separate heartwood from the non-durable sapwood. The objectives of this study were to evaluate near infrared (NIR) spectroscopy as a non-destructive method for classifying heartwood and sapwood in Scots pine sawn wood, and to evaluate the applicability of NIR-spectroscopy in predictions of heartwood resistance to decay. Wood durability is measured by mass loss from fungal activity in a laboratory experiment.Using NIR-spectra in fully cross-validated partial least squares (PLS1) regression models, results show that it is possible to correctly classify samples of heartwood and sapwood. The results further demonstrate that resistance to decay in Scots pine heartwood and sapwood can be modelled with satisfying precision using NIR-spectroscopy. Within-tree variation in heartwood resistance to decay show the importance of building reliable models for identification of highly decay resistant heartwood, to accomplish a purposeful utilisation of naturally durable heartwood.
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Inge Stupak Møller Staffan JacobsonAbstract
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– Bumblebee foraging - is closer really better?
Wenche E. Dramstad, Gary L.A. Fry, Marie J. Schaffer
Authors
Wenche E. Dramstad Gary L.A. Fry Marie J. SchafferAbstract
Bumblebees are important pollinators of crops and wild flowers, and their foraging range has considerable management interest. It is commonly assumed that bumblebees prefer to forage as close to their nest as possible. However, a review of the literature shows that there is little empirical evidence to support this assumption. An experiment aimed at investigating whether bumblebee workers forage close to their nests, and distances between three commercially produced bumblebee nests and an introduced forage patch were manipulated. The results presented here show that bumblebee workers significantly increased their use of a flower resource after their nests had been moved from within the resource to more than 100 m away.