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.
2016
Abstract
Due to more restrictive toxicological requirements and increased ecological awareness of consumers, wood preservatives containing harmful biocides are no longer desired on the market. Therefore, research on new environmentally friendly formulations is of great importance. One of the possible solutions is to develop new preservatives based on natural substances, which are harmless to humans, animals and the environment, while biologically active. The aim of the study was to develop new biocide-free preservative systems which increase wood resistance to wood-decaying fungi. The following silanes: [3-(2-Aminoethylamino)propyl]trimethoxysilane (AATMOS), (Aminopropyl)triethoxysilane (APTEOS), and (Aminopropyl)trimethoxysilane (APTMOS); caffeine, natural oils and potassium carbonate were chosen as components of new protective formulations, which were planned to be an alternative for traditionally used biocides. Samples of three different wood species (pine, spruce, and poplar) were treated with the new preservative systems and exposed to the brown-rot fungus Coniophora puteana and the white-rot fungus Coriolus versicolor according to EN-113 and EN-839 standards. The obtained results show that wood treated with the water-based formulation consisting of silanes and caffeine (2% caffeine + 5% AATMOS, 2% caffeine + 5% APTEOS) demonstrated the highest resistance to the test fungi. Wood mass loss after exposure to the decay fungi was 1%. All wood species treated with this formulation achieved index 1 (“very resistant”) within durability class acc. to the EN350 standard.
Abstract
Understanding the influence of weathering factors and the material degradation mechanisms are fundamental for modelling the weathering process of wood. The goal of this work was to investigate the combined effect of time and exposure on the physical-chemical mechanisms of wood weathering. Four exposure directions (North, South, East and West) were investigated. Experimental tests were performed for 28 days through July, which according to previous research is considered as the most severe period for weathering of wood micro-sections. Measurements of samples included: photogrammetry, near and mid infrared spectroscopy, colour measurement, SEM observation and visual assessment. Parameters obtained by measuring the weathered surfaces with various sensors were compared with the subjective visual assessment by an expert evaluator. Algorithm based on multi sensor data fusion allowing calculation of the “weathering indicator” was developed. It was concluded that the progress of degradation is clearly correlated to the solar radiation and the exposure direction seems to have a clear effect on the degradation intensity.
Abstract
Growth of dark moulds enables the use of a decorative and protective biofinish for wood, showing advantages compared to traditional wood-coatings in terms of sustainability and selfrepair. Based on the formation of a uniform mould covering on oil treated wood during outdoor exposure, the utilisation of a biofinish is in development. Basic information is lacking on the correlation between exposure site and biofinish formation on wood. To evaluate the impact of different locations, a biofinish assessment method was applied on different combinations of wood species and vegetable oil types after outdoor exposure in the Netherlands and Norway. Biofinishes were detected on wood samples made of spruce, pine sapwood and ilomba that were treated with olive oil and on pine sapwood treated with raw linseed oil after one and a half year of outdoor exposure in the Netherlands. More time was needed for biofinish formation on multiple wood-oil combinations for samples exposed in Norway. After two years of outdoor exposure three out of five wood-oil combinations that contained biofinishes in the Netherlands, showed similar results with the samples in Norway. Biofinish formation was not detected at all on untreated wood samples, regardless the wood species or exposure site. Loose fibres were observed on the surface of all untreated samples. It is likely that biofinish formation was prevented by the removal of stained fibres. Analysis of the stain coverage development on the wood samples, including initial stages of biofinish formation, showed a significant effect of exposure time and (oil) treatment on the stain coverage.
Authors
Lone RossAbstract
No abstract has been registered
Abstract
In order to determine the relation between the structural properties and fungistatic activity of quinolizidine and bisquinolizidine alkaloids, the bioactive derivatives of cytisine, sparteine and lupanine were tested for the inhibitory activity against the microfungus causing mould growth phenomenon (Aspergillus niger van Tieghem ATCC 6275). The compounds tested were screened for antifungal properties using the bioautography-TLC. According to the results, the following cytisines showed an inhibiting effect on mould; spirocytisine, 3,5-dibromocytisine, bromo-N-boccytisine, N-Boccytisine, 3-bromobenzylocytisine, 4-bromo-benzylcytisine, 3-iodobenzylcytisine, 4-iodobenzylcytisine.
Authors
Anna Sandak Ingunn Burud Andreas Svarstad Flø Thomas Kringlebotn Thiis Lone Ross Jakub SandakAbstract
No abstract has been registered
Authors
Lone RossAbstract
No abstract has been registered
Authors
Lone RossAbstract
No abstract has been registered
Authors
Knut Arne Smeland Kristian Hovde Liland Jakub Sandak Anna Sandak Lone Ross Thomas Kringlebotn Thiis Ingunn BurudAbstract
Untreated wooden surfaces degrade when exposed to natural weathering. In this study thin wood samples were studied for weather degradation effects utilising a hyperspectral camera in the near infrared wavelength range in transmission mode. Several sets of samples were exposed outdoors for time intervals from 0 days to 21 days, and one set of samples was exposed to ultraviolet (UV) radiation in a laboratory chamber. Spectra of earlywood and latewood were extracted from the hyperspectral image cubes using a principal component analysis-based masking algorithm. The degradation was modelled as a function of UV solar radiation with four regression techniques, partial least squares, principal component regression, Ridge regression and Tikhonov regression. It was found that all the techniques yielded robust prediction models on this dataset. The result from the study is a first step towards a weather dose model determined by temperature and moisture content on the wooden surface in addition to the solar radiation.
Authors
Lone Ross Thomas Kringlebotn Thiis Geir Isak Vestøl Ingunn Burud Solrun Karlsen Lie Olav Albert HøibøAbstract
Use of uncoated wood in building façades has increased the last years, and therefore it is important to understand and control the aesthetical character and appearance of wood materials used outdoors. By predicting the aesthetical service life and the visual appearance of a wooden façade over time, we can accommodate some of the end-user expectations, perception, values and aesthetical preferences. The spatial variation of climate on a façade is large, and estimation of the weathering process and mould growth on outdoor exposed wood should be based on the actual surface climate rather than data from meteorological stations. A first version of a simulation model that aims to predict and visualize future aesthetical appearance of wooden façades has been developed. The model is based on existing mould growth models and on a new model for surface meteorological conditions that account for RH, temperature and UV. The on-set of mould growth on selected wood materials (pine, spruce, larch, oak, aspen, thermally treated pine) have been studied in 8 different controlled climate conditions, where two levels of surface condensation regimes have been mimicked to capture time-of-wetness. Wood samples in conditions with high RH (85%) and longest time-of-wetness had the earliest on-set of mould growth, and under these conditions temperature (25°C/10°C) had no significant impact. Generally aspen had the earliest on-set of mould growth and thermally treated pine the latest. Data on on-set of mould growth will be incorporated in the simulation model to enable a knowledge-based decision tool regarding design and material selection.