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.
2008
Forfattere
Peder GjerdrumSammendrag
Pine (Pinus sylvestris) heartwood and pine sapwood can, in several respects, be considered two different timber products. Sapwood demonstrates open structures that easily adsorb moisture and is vulnerable to bio-chemical disintegration, but also more easily painted, glued or impregnated. Heartwood, on the other hand, is less disposed to moisture fluctuations, hence, more dimensionally stable, and durable. Heartwood content is closely related to cambial age and to the progress of annual ring width. It is also the nature of pine is to grow timber of quite varying quality along the stem. Resins are more abundant near the base, and the knottiness is shifting, following certain patterns from the base upwards. Several of those traits can be identified prior to breakdown, applying specific wood technology knowledge, recent research and standard log scanner equipment. Even with this potential for producing more homogeneous board quality by including heartwood in the breakdown decision basis, one should not forget the practical implications for the sawmill. The cost of keeping separate heartwood quality classes and the risk of mistakes might easily exceed the price gain.
Forfattere
Jan Stenlid Matteo Garbelotto Ursula Kües James B. Anderson Francis Martin Halvor SolheimSammendrag
No abstract has been registered
Forfattere
Jan Stenlid Åke Olson Kerstin Dalman Magnus Karlsson Mikael Brandström Karl Lundén Carl Gunnar Fossdal Matteo Garbelotto Frederick AsiegbuSammendrag
Heterobasidion annosum s.l. causes a devastating root rot in conifer plantations and natural forests throughout the northern hemisphere. The genome sequencing of H. annosum will provide the first comprehensive genetic information on a plant pathogenic homobasidiomycete allowing for new insights into plant-microbe interactions with trees, in particular conifers. It is important to broaden the taxonomic base for understanding the mechanisms of plant-microbe interactions, studying genes and proteins involved, and identifying pathogenicity determinants. Comparative genomics of plant pathogens with a gradient of taxonomic relatedness to H. annosum will help to understand the evolution of such factors. The project involves resequencing of several species in the H. annosum species complex including pathogenic and non-pathogenic species. Comparisons can also be made with fungi with different nutritional relations to plants; necrotrophic, biotrophic and mycorrhizal mutualist. The project integrates genetic approaches e.g QTL mapping with comparative genomics. Data bases generated on genes under positive selection in the sequenced genomes will be compared with candidate genes derived from published QTL mapping and EST-projects but also known pathogenicity factors in other pathosystems.
Forfattere
Gunnar Austrheim Leif-Jarle Asheim Gunnar Bjarnason Jon Feilberg Anna Maria Fosaa Øystein Holand Kenneth Høegh Ingibjörg S. Jónsdóttir Borgthor Magnusson Lis E. Mortensen Atle Mysterud Erla Olsen Anders Skonhoft Geir Steinheim Gudrun ThórhallsdóttirSammendrag
No abstract has been registered
Sammendrag
A possible cost-effective real-time patch spraying implementation against seed-propagated broad-leaved weeds in cereals is a camera mounted in front of the tractor taking images at feasible distances in the direction of travel, on-board image analysis software and entire boom switched on and off. To assess this implementation, manual weed counts (0.25 m(2) quadrats) in a 1.5 m x 2 m grid, were used to simulate camera outputs. Each quadrat was classified into 'spray' and 'not spray' decisions based on a threshold model, and the resulting map defined the 'ground truth'. Subsequently, 'on/off' spraying at larger control areas where sizes were given by the boom width and image distance, and spraying decision controlled by weed status at the single quadrat simulating the camera's view, were simulated. These coarser maps were compared with 'ground truth', to estimate mapping error (area above threshold not sprayed), spraying error (area below threshold sprayed), total error (sum of mapping and spraying error) and the herbicide reduction. Three levels of the threshold model were tested. Results were used to fit models that predict errors from boom width and image distance. Size of control area did not on average affect the magnitude of the simulated herbicide reductions, but the bigger the control area the higher the risk that the simulated herbicide reduction deviate from the reduction in 'ground truth'. Mean simulated herbicide reductions were 42-59%, depending on threshold level. Only minor differences due to threshold level were seen for mean mapping and spraying errors at given spraying resolutions. Using original threshold level and image distance 2 m, predicted total errors for boom widths 2 m, 6 m, 20 m and 40 m would be 6%, 10%, 16% and 17%, respectively. Results indicate that control area should not exceed about 10 m 2 if acceptable total error is maximum 10%.
Forfattere
Svein Solberg Dan J. Weydahl Erik NæssetSammendrag
No abstract has been registered
Forfattere
David Bredström Patrik Flisberg Mikael RönnqvistSammendrag
In this paper we discuss some computational experiments on simulating refinery operations. We compare an integrated approach with recursively solving a production planning and sales planning problem. We test two different descriptions of the demand behaviour. The first is based on a fixed lower and upper limit and the second on a demand that varies with the product price. We also test the impact of different number of time periods in the planning horizon. We simulate the behaviour when detailed information of the demand is available.
Forfattere
Hideo Sakai Nordfjell Tomas Kjell Suadicani Bruce Talbot Ebbe BøllehuusSammendrag
No abstract has been registered
Sammendrag
No abstract has been registered
Sammendrag
No abstract has been registered