Time filter

Source Type

Sharapov E.,Volga State University of Technology | Mahnert K.-C.,Norwegian Institute of Wood Technology | Militz H.,University of Gottingen
European Journal of Wood and Wood Products

Scots pine (Pinus sylvestris) was thermally modified and its residual strength after cyclic bending was tested. Asymmetric sinusoidal cyclic oscillations at 20 Hz frequency and load ratio p = 0.3 were conducted. The variables of the experiment were the thermal treatment temperature (160, 190 and 220 °C), the number of bending oscillations (103, 505 × 103 and 106) and the equilibrium moisture content at target climates of 20 °C and 35, 65 and 95 % relative humidity (RH). The results showed that all input variables were insignificant for the residual modulus of elasticity. The initial moisture content of the specimens before fatigue testing and the maximum thermal modification temperature were identified as main influence on the residual modulus of rupture. The cyclic creep deflection significantly increased with increasing number of loading and initial specimen moisture content. © 2016 Springer-Verlag Berlin Heidelberg Source

Alfredsen G.,Norwegian Forest And Landscape Institute | Flaete P.O.,Norwegian Institute of Wood Technology | Militz H.,University of Gottingen
International Wood Products Journal

Acetylation appears suited to provide adequate protection against biological attack for materials derived from non-durable wood species. But still there are unanswered questions related to resistance against fungal decay. The paper summarises existing knowledge related to fungal deterioration of acetic anhydride modified wood and also highlights future research opportunities. In addition, statistical analyses based on previously published decay fungi studies were performed to quantify what factors contribute most to the performance (calculated as test sample/ control). The results showed that weight per cent gain can explain approximately 50% of the performance for acetic anhydride treated wood. Others of the applied variables, like wood species or type of fungus, can reduce the variance in performance by additional 15%. Based on the surveyed literature the degree of cell wall bulking in combination with lowering of the equilibrium moisture content seems to be the primary mode of action. © 2013 IWSc, the Wood Technology Society of the Institute of Materials, Minerals and Mining. Source

Thiis T.K.,Norwegian University of Life Sciences | Burud I.,Norwegian University of Life Sciences | Kraniotis D.,Norwegian Institute of Wood Technology | Gobakken L.R.,Norwegian Forest And Landscape Institute
Energy Procedia

Mold growth on the surface of wooden façades is usually dealt with by using surface treatment such as paint with fungicides. However, new developments in architecture are moving towards less use of coating, and more use of untreated wooden claddings. Mould growth is well understood and described, and several models for predicting mould growth on building materials exist. It is commonly known that mould growth is directly controlled by the climate which the wood is exposed to. Several authors identify humidity, temperature and time as the main drivers of mould growth. However, most of the current growth models developed are based on laboratory measurements at stable climatic conditions. Consequently, these models are less suitable for prediction of mould growth on exterior surfaces exposed to rapidly changing weather conditions. This paper analyses the effect of variations of meteorological data on the mould growth on wooden claddings. An experimental setup of wood samples was exposed to outdoor conditions and hourly weather conditions as well as the mould growth at different intervals were measured. The measurements were supplied with 1-D Heat And Moisture (HAM) simulations to provide a more accurate estimate of the conditions on the surface of the samples. The purpose of the analysis was to evaluate if an existing mould growth model might be applicable also for predicting outdoor mould growth. Several profiles of temperature and moisture were continuously monitored on different locations of an eight-story building made from Cross Laminated Timber (CLT). The results from the analysis of the samples of wood cladding were used to model the mould growth on different locations of the building. Also the drying effect of wind around the building was studied. The study shows that there is large variation of potential mould growth on the façade of the building. © 2015 The Authors. Source

Ulvcrona T.,Swedish University of Agricultural Sciences | Flaete P.O.,Norwegian Institute of Wood Technology | Alfredsen G.,Norwegian Forest And Landscape Institute
European Journal of Wood and Wood Products

Various oils can be used to lower the equilibrium moisture content and increase the service life of Scots pine wood products. The aim of this study was to investigate effects of the lateral wood zone on the brown rot resistance of untreated and linseed oil-impregnated Scots pine wood in a laboratory test (EN 113). Significant differences were found in the mean mass losses of treated and untreated specimens taken from three lateral heartwood zones, but not between specimens taken from sapwood. The treatment had no significant effect on sapwood, although it seems to have some positive effect on the durability of heartwood, apparently due to interactive effects with the high extractives contents of heartwood. © Springer-Verlag 2012. Source

Raty T.,Finnish Forest Research Institute | Toppinen A.,University of Helsinki | Roos A.,Swedish University of Agricultural Sciences | Riala M.,Finnish Forest Research Institute | Nyrud A.Q.,Norwegian Institute of Wood Technology
Business Strategy and the Environment

The purpose of our study is to explore how companies operating in the Nordic wood products value chains currently use environmental performance measures in their environmental policy and communication with stakeholders. Apart from the regularly-used environmental management certificates, the ability of wood material to store carbon and the use of sustainable forest management certificates open up interesting strategic options for firms in the implementation of their environmental policy. The primary was collected through thematic managerial interviews in 2011 from 37 companies in Finland, Sweden and Norway, of varying size, roles in the value chain, conditions for green business practices and exports. Forest certification and environmental management systems were frequently used, but managers did not always perceive them to be useful, particularly for raising environmental awareness at the final consumer level. Nevertheless, the general attitude towards using environmental performance measures was seen as positive. Companies with a business-to-business orientation were the most proactive in terms of environmental communication, whereas companies in consumer markets were more reactive. The key stakeholders targeted for environmental communication were value chain partners and the authorities, and only to a lesser degree employees and environmental non-governmental organisations. The key strategic role of environmental management and communication appeared to be securing the firms against negative environmental claims. The Nordic wood industry could improve their communication if the strategic orientation is shifted from the forest certification to the use of generic eco-labels, and most of all, to the adoption of quantitative measures like carbon footprints and environmental product declarations. © 2016 John Wiley & Sons, Ltd and ERP Environment. Source

Discover hidden collaborations