Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2009
Forfattere
Rastislav Solár Miroslav Mamo Janka Dibdiakova Jarmila GeffertováSammendrag
A series of comparable specimens of spruce wood were submitted to chemical pre-treatments. Chemical pre-treatments were carried out with diluted sodium hydroxide, or sodium hydroxide and then by hydrogen peroxide, or per-acetic acid. All pre-treatments modified the chemical composition of wood and led to its weight loss. The pre-treatments resulted in a complete deacetylation, and partial delignification of wood and did not cause apparent loss of cellulose. Chemical alterations of the pre-treated spruce wood were markedly reflected in its improved digestibility under conditions of kraft cook. The obtained pulps were characterized with apparently reduced content of residual lignin, lower yield, moderate drop in DP, higher brightness and better optical properties (colour and lightness) of both unbleached and bleached pulps.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Modified wood is commercially available and merchandized as a new, environmentally friendly and durable wood species. However, there are no standards focusing on the evaluation of modified wood. Combining resistance against fungal decay and good ecotoxicological properties may be a start. In this study softwood and hardwood species were furfurylated using different treatment processes and treating solutions. The durability was determined by exposing the treated wood to a range of Basidiomycetes and the ecotoxicity was studied on two aquatic organisms.It was the purpose to come to a strategy and how to unite efficacy and ecotoxicity, since this is important in product development. The results show that the selection of fungus used for mass loss determination and the choice of ecotoxicity method is decisive, confirming that a combination of methods is valuable. A tiered approach to find the optimal treatment seems the best option. First, adequate protection against wood-rotting fungi should be attained, followed by ecotoxicity evaluation of the wood leachates. If necessary, the optimization process should be repeated until both durability and ecotoxicity are within satisfactory limits. This process could be extended with other evaluation criteria, e.g. dimensional stability of the modified wood or a risk analysis of its leachate.
Sammendrag
One of the main challenges for modified wood and modified wood based WPCs (Wood Plastic Composites) is to predict accurate service life time in UC3 (Use class 3, above ground) and UC4 (in soil or fresh water contact). So far, data from in-service conditions are rare, while several studies have evaluated the durability in lab or field test exposure. However, there is still a lack of studies comparing replicate modified wood products in both field and lab exposure. This study evaluates the efficacy of modified wood and modified wood based WPCs in AWPA E10, three different types of soil in lab (ENV 807), three test fields in-ground (EN 252) and two test sites close to ground (horizontal double layer test)......
Sammendrag
A catchment provides ecosystem data along with (relatively) simple, operationally defined boundaries. In addition runoff is an integrated measure of the hydrochemical ecosystem response, which can be represented by fluxes at the weir. Integration at the weir occurs first of all with respect to spatial scales. Almost all fluid output leaves a (tight) catchment at this point. Evaluation of the runoff dynamics (quantity and quality) is primarily concerned with temporal scales. The Lange Bramke catchment study with its four runoff series from forested catchments (spring and weir at Lange Bramke, weirs at Dicke Bramke and Steile Bramke) provides an exceptionally comprehensive data set. The following scales and processes can be considered, when interpreting temporal variations in runoff data: above the time scale of forest rotation (species composition, biomass accumulation, timber export, soil nutrient pools) at decadal time scales up to a full forest rotation of about 100-120 years (changes in forest growth rate, changes in deposition, climate change, insect outbreaks) at annual time scales (uptake, transpiration) at hourly to weekly time scales of hydrological events (precipitation, runoff, dilution effects of solvents).
Sammendrag
Long-term monitoring meteorological, hydrological and hydrochemical data from small catchments are irreplaceable witnesses of past environmental conditions. This insight shaped the formation of the Long-Term Ecological Research Network (LTER) in the US, but European as well as German siblings are under preparation. Among the European forested monitoring sites, the Bramke catchments in the Harz mountains present a particularly well-documented case, with daily runoff measurements starting after World War II-related reparation cuts in 1948, and surface water chemistry being observed since the 1970ies. Originally powered by research on erosion, then by acid rain research and the then-prominent “forest decline”, a large set of hydrochemical variables (major ions) is available now with basically weekly resolution. Previously tightly connected to academic research at the University of Göttingen, routine measurements are by now performed by local forest authorities, ensuring forthcoming continuity even when public attention should shift away again from climate change research.
Forfattere
Richard Fischer Martin Lorenz Michael Köhl Georg Becher Oliver Granke Alexey Bobrinsky Tatyana Braslavskaya Wim de Vries Matthias Dobbertin Philipp Kraft Daniel Laubhann Natalia Lukina Hans Dieter Nagel Gert Jan Reinds Hubert Sterba Svein Solberg Silvia Stofer Walter SeidlingSammendrag
Det er ikke registrert sammendrag
Sammendrag
Wood is a traditional building material but in general it underlies restrictions in outdoor applications due to its respective durability against microbiological decay. To face this problem, different impregnation systems are applied to enhance the materials\" servicelife. Scots pine (Pinus sylvestris) is the most widely distributed pine in Eurasia and hence easily available. Despite of the previously defined good treatability of Scots pine sapwood, large differences in treatment performance are reported from industry. As process parameters are always adjusted to the material most difficult to treat, permeability variations in wood material are an economical problem. Therefore, it is important to understand the material in order to make a more reasonable material selection possible.....
Sammendrag
The durability of wood in exterior use is limited by to climatic factors and wood deteriorating organisms. The natural durability of the Nordic wood species is generally regarded as low, and for e.g. decking and use in soil contact wood protection is needed. Within the last years, new non-biocidal treatments, like wood modification systems, have been developed to improve the biological resistance of wood. For information about the decay resistance of untreated and modified wood, natural outside exposure is necessary. European standard EN 252 is the main field test method for use class 4. In use class 3 the need of new or improved test setups has been put forward. Traditionally evaluation of field trials has mainly been based on visual evaluation and pick-test. However, to get in depth knowledge about: 1) different field trial methods and 2) fungal colonization of new wood protection systems, additional assessment methods can be used. Hence, comparative studies are needed.....
Sammendrag
Information given in EN 350-2 on natural durability of different wood species against wood destroying fungi is mainly based on heartwood tested in ground contact. The objective of this study was to test and compare durability of many different wood species in a field test in ground contact. The material consisted of Norwegian wood species able to give sufficient sawn wood dimensions (commercial and less utilised species, indigenous and introduced species) and imported species (Larch from Russia; Oak, Douglas fir and Western Red Cedar from North America; Merbau and Teak from Asia). Additionally, modified wood (thermally modified and tall oil treated) and preservative treated wood (CCA- and Cu-preservative) were included in the test. The wood types, 31 in total, were tested according to EN 252 and EN 350-1 at NTIs test site in Sørkedalen, Norway. Results after five years exposure show that most of the Norwegian grown wood species have low durability. This study also provides information on durability of four species not included in EN 350-2: Juniperus communis, Salix caprea, Sorbus aucuparia and Populus tremula.