Katrin Zimmer
Forsker
Biografi
Katrin Zimmer er forsker i avdeling driftsteknikk og digitalisering. Hun har mer en 20 års erfaring med bruk av tre. Hun er utdannet snekker, studerte treteknologi ved universitet i Hamburg, og skrev doktorgraden ved Norges miljø- og biovitenskapelige universitet om "Variasjon i impregnerbarhet i furu yteved fra nord Europa".
Hun fokuserer arbeidet sitt på å øke bruk av mindre brukte treslag som bjørk, spesielt med hensikt på materialutvikling og vekst spesifikke virkes egenskaper. Hun er også ansvarlig for kommunikasjons aktiviteter innen SFI SmartForest.
Sammendrag
This study investigates the moisture-induced recovery of temporary property changes in thermo-mechanically densified (TMD) birch and aspen wood, compared to thermally modified (TM) wood. Both treatments were prepared under identical thermal conditions, differing only by compression in TMD. Dimensional stability, water vapour sorption, and Brinell hardness were assessed before and after repeated wetting and drying cycles to evaluate the effect of stress storage in the polymer matrix and its recovery during moisture exposure. The results indicate that both TMD and TM treatments induce a temporary reduction in moisture uptake, consistent with the formation of an annealed polymer structure. Water saturation and subsequent drying restored higher moisture content and reduced Brinell hardness in TMD wood, highlighting a moisture-driven recovery of the annealed polymer conformation. Notably, the decrease in hardness could not be attributed solely to the reduction in bulk density, indicating additional effects of polymer plasticisation. The presence of compression stresses during TMD appeared to enhance stress storage, thereby influencing the recovery of moisture-induced properties. Initial wood moisture content before TMD had little effect on the temporary reduction in moisture content, suggesting that annealing also occurs in dry states. These findings emphasise the need to account for moisture cycling in TMD wood’s service life. Future work should focus on the interplay between compression stresses and the annealing effect to reduce the temporary nature of the property improvements by TMD.
Forfattere
Katrin ZimmerSammendrag
Det er ikke registrert sammendrag
Forfattere
Katrin ZimmerSammendrag
Det er ikke registrert sammendrag
Divisjon for matproduksjon og samfunn
Utnyttelse av trefiber og avfallsstrømmer for bærekraftige og sirkulære dyrkingsmedier i hagebruket (‘SUBTECH 2.0’)
Divisjon for skog og utmark
SFI SmartForest: Bringing Industry 4.0 to the Norwegian forest sector
SmartForest will position the Norwegian forest sector at the forefront of digitalization resulting in large efficiency gains in the forest sector, increased production, reduced environmental impacts, and significant climate benefits. SmartForest will result in a series of innovations and be the catalyst for an internationally competitive forest-tech sector in Norway. The fundamental components for achieving this are in place; a unified and committed forest sector, a leading R&D environment, and a series of progressive data and technology companies.