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.
2017
Forfattere
Nicholas ClarkeSammendrag
No abstract has been registered
Sammendrag
Mould growth is an important contributor to colour change of untreated wood exposed outdoors. Predicting the development of mould growth is therefore important to ensure successful use of untreated wood as a façade material. More knowledge about the factors affecting mould growth on outdoor exposed wood is required to give better predictions. In this study, climatic factors and material properties affecting mould growth have been investigated by exposing selected wooden specimens (aspen, pine sapwood, pine heartwood, spruce sapwood and spruce heartwood) to 8 different climates for 91 days. The climates were defined in a factorial design with two levels of relative humidity (65 and 85 %), wetting period (2 and 4 hours per day) and temperature (10 and 25 °C), respectively. The degree of mould growth was visually evaluated once a week during the exposure period. Aspen and pine sapwood were the substrates most susceptible to mould growth. There were no significant differences in susceptibility between pine heartwood and spruce heartwood, but the difference between heartwood and sapwood was significant for both pine and spruce. The effect of density on mould growth was tested for the spruce heartwood material, but was not found to reduce the residual variance significantly. However, all the tested climatic factors affected mould growth significantly; relative humidity was most important, while there was a somewhat smaller effect of wetting period and a minor effect of temperature. Overall, increased RH, longer wetting period and increased temperature had a positive effect on the mould growth. It was found a significant interaction between temperature and relative humidity, indicating that the temperature had larger effect on the mould growth at lower relative humidity, and that the relative humidity had larger effect at lower temperature. There was a tendency that the relative performance of the substrates was dependent on climate, but this interaction effect was not significant for any of the climatic factors.
Sammendrag
No abstract has been registered
Forfattere
Mekjell MelandSammendrag
No abstract has been registered
Forfattere
Nicholas Clarke Silje Skår O. Janne Kjønaas Kjersti Holt Hanssen Tonje Økland Jørn-Frode Nordbakken Toril Drabløs Eldhuset Holger LangeSammendrag
Short-term (three to four years) effects of forest harvesting on soil solution chemistry were investigated at two Norway spruce sites in southern Norway, differing in precipitation amount and topography. Experimental plots were either harvested conventionally (stem-only harvesting, SOH) or whole trees, including crowns, twigs and branches were removed (whole-tree harvesting, WTH), leaving residue piles on the ground for some months before removal. The WTH treatment had two sub-treatments: WTH-pile where there had been piles and WTH-removal, from where residues had been removed to make piles. Increased soil solution concentrations of NO3–N, total N, Ca, Mg and K at 30 cm depth, shown by peaks in concentrations in the years after harvesting, were found at the drier, less steep site in eastern Norway after SOH and WTH-pile, but less so after WTH-removal. At the wetter, steeper site in western Norway, peaks were often observed also at WTH-removal plots, which might reflect within-site differences in water pathways due largely to site topography.
Sammendrag
Tunnel production of sweet cherry results in higher yields of larger fruit than in the open. When cherry trees were grown under tunnels in Norway, fruit cracking was higher in a year when soils were saturated and when 20 ppm gibberellic acid was applied at straw color. In this study we evaluated the effect of soil moisture on fruit cracking under tunnels. In 2013, a trial on mature 'Sweetheart'/'Colt' trees growing under high tunnels was initiated. Each plot consisted of 8 trees, spaced 2×4 m apart with 'Lapins' as guard trees. Experimental design was a split-plot design with or without 20 ppm GA3 application at straw color; and three drip irrigation regimes (zero, deficit and full based on evapotranspiration). During the season, soil water content was monitored weekly. Due to unfavorable weather conditions during bloom time, crop loads were lower than normal. Average fruit sizes were large and GA3 application at yellow straw color resulted in small increases in average fruit diameter and fruit weight with all three irrigation treatments. Fruit cracking was very variable and occurred almost exclusively at the distal side of fruit and not on the stem side. GA3-treated fruit cracked slightly more than untreated fruit. There were no differences in fruit cracking due to irrigation scheme.
Forfattere
Gary Dobson Gordon J. McDougall Derek Stewart Miguel Ángel Cubero Reijo O. KarjalainenSammendrag
The effects of juice matrix and pasteurization on the stability of total phenols and especially total and indi- vidual anthocyanins were examined in black currant (BC) juice and mixtures with apple, persimmon, and peach juices at 4 °Cand20°C. Total phenol content decreased in all juices at both temperatures but there was a trend to lower levels in unpasteurized over pasteurized juices. Differences in the decline of total anthocyanins between pasteurized and unpasteurized juices varied according to the juice type and the storage temperature. At 4 °C storage, anthocyanins declined in all juices according to pseudo 1st-order kinetics and there were only small differences in the rates between pasteurized and unpasteurized juices. However, at 20 °C, although pasteurized and unpasteurized BC juices and pasteur- ized mixed juices followed pseudo 1st-order kinetics, there was a different pattern in unpasteurized mixed juices; a rapid initial decline was followed by a slowing down. The effect of the added juice on anthocyanin decline was also different at either temperature. At 4 °C, the anthocyanins decreased faster in mixed juices than BC juice alone, but at 20 °C, at least in pasteurized mixed juices, the decline was similar or even slower than in BC juice; there were only small differences among the 3 mixed juices. At 20 °C, in pasteurized and unpasteurized BC juices, the rate of decrease was essentially the same for all 4 individual anthocyanins but in the mixed juices the 2 glucosides decreased significantly faster than the 2 rutinosides.
Forfattere
Alice Budai Lucia Calucci Daniel Rasse Line Tau Strand Annelene Pengerud Daniel Wiedemeier Samuel Abiven Claudia ForteSammendrag
Infrared and 13C solid state nuclear magnetic resonance spectroscopies and benzene polycarboxylic acids (BPCA) analysis were used to characterize the structural changes occurring during slow pyrolysis of corncob and Miscanthus at different temperatures from 235 °C to 800 °C. In the case of corncob, a char sample obtained from flash carbonization was also investigated. Spectroscopic techniques gave detailed information on the transformations of the different biomass components, whereas BPCA analysis allowed the amount of aromatic structures present in the different chars and the degree of aromatic condensation to be determined. The results showed that above 500 °C both corncob and Miscanthus give polyaromatic solid residues with similar degree of aromatic condensation but with differences in the structure. On the other hand, at lower temperatures, char composition was observed to depend on the different cellulose/hemicellulose/lignin ratios in the feedstocks. Flash carbonization was found to mainly affect the degree of aromatic condensation.
Sammendrag
No abstract has been registered
Sammendrag
No abstract has been registered