Your search resulted in 235 documents. Displaying 25 entries per page.
In-ground variability of decay intensity within a test field
2012 - IRG/WP 12-20496
Timber exposed in the ground faces most severe conditions in terms of exposure to wetting and fungal decay in the terrestrial environment, therefore wood durability tests are often conducted in test fields preferably ensuring the occurrence of all relevant decay organisms. One can also expect differences in decay within an individual field-test site due to localized distribution of certain organis...
C Brischke, S Olberding, L Meyer, T Bornemann, C R Welzbacher
The effects of acetylation level on the growth of Postia placenta over 36 weeks
2012 - IRG/WP 12-40589
Genomic sequencing gives us a tool to systematically and rapidly discover novel genes, how their products function in the cell, and explore their interactions. When the DNA sequences are known, primers can be designed to detect transcripts of genes with gene products related to basic cellular processes and hyphal growth. The characteristic gene products induced in different fungi by different wood...
A Pilgård, G Alfredsen, C G Fossdal, C J Long II
Mould growth on wood-based materials – a simulated in-service study
2012 - IRG/WP 12-20503
Ten different wood-based materials including preservative-treated wood, fire retardant-treated wood, modified wood, WPCs and untreated references of pine sapwood and spruce were placed in three different environments (an attic and two crawl spaces) for a period of 26 months. Mould growth was analysed at five to seven month intervals in an effort to map the growth development. The relative humidit...
G Bok, P Johansson, J Jermer
Influence of a pulsed electric field on the growth of surface fungi
2013 - IRG/WP 13-10795
The colonization of mold and staining fungi are not only an aesthetical problem. Blue stain fungi are able to penetrate paint films. Maintenance of coatings on wood are time consuming and costly. A new approach uses a pulsed electric field (PLEOT) in order to protect wood against surface fungi. This technology is evaluated in non-sterile laboratory conditions on different coated and uncoated Scots...
M Starck, A Treu
Detection of Aureobasidium as the dominant fungus on coated wood
2013 - IRG/WP 13-10796
Wood is often covered with a coating in order to protect the surface. Unwanted dark mold growth on paint covered surfaces in external conditions is a familiar phenomenon. Simple microbial techniques have commonly been used to determine the dominant fungal species present in the discoloured area, for example morphological analysis of microscopic preparations of fungal pieces sticking to an adhesive...
E J Van Nieuwenhuijzen, M F Sailer, R A Samson, O C G Adan
Inhibitory extractives or nutrients? Mould growth on coated heartwood and sapwood of Pinus sylvestris and Gleditsia triacanthos
2013 - IRG/WP 13-10806
Sometimes mould fungi grow over weathered coated sapwood, whereas the coated heartwood is not colonised. Two factors may be responsible for these differences: Either the larger content of nutrients in the sapwood, or the content of biocidal extractives in the heartwood. In this study the factors for the difference in mould growth on coated heartwood and sapwood of Pinus sylvestris (Scots Pine) and...
D Lukowsky, N Buddruhs
Statistical analysis of durability tests - Part 2: Principles of time-to-failure and application on field test data
2013 - IRG/WP 13-20512
Service life prediction is an important topic in wood research, especially with regard to the Construction Products Regulation (CPR). Both laboratory tests as well as in-service performance testing is therefore essential, in combination with proper monitoring and analysis tools. A crucial concept is variability and the incorporation of variability in tests and analysis. In this paper we focus on t...
J Van den Bulcke, I De Windt, C Brischke, C R Welzbacher, A O Rapp, J Van Acker
Service life evaluation of wood - an engineering approach
2013 - IRG/WP 13-20515
A performance-based service life design format based on climatic exposure on one hand and “biological wood resistance” on the other hand is presented in this paper. Important concepts are the introduction of limit states as well as reliable performance models for the biological processes, by which onset of deterioration can be predicted for arbitrary climate histories. Examples of applications...
S Thelandersson
Predicting the Rate of Decay, and the Potential for Misinterpretation of Proper Scientific Method
2013 - IRG/WP 13-20525
Predicting the rate of fungal attack in wood-based materials and its effect on properties remains the holy grail of wood products pathologists; however, achieving this goal is difficult because of the many variables associated with the process. This paper reviews some of the more important aspects of the decay process in relation to test methodology and then discusses how data are sometimes used b...
B S Goodell, J J Morrell
The activity of a wood-decaying fungus during drying and rewetting cycles measured by isothermal calorimetry
2013 - IRG/WP 13-20526
Wood decaying fungi are an essential part of any ecosystems as they are the main decomposers of cellulose and lignin-containing materials. But as wood is a common building material the risk for decay fungi growth and subsequent degradation of our construction material is a concern. There are important physiological aspects of the growth and activity of decay fungi that are unknown today, and witho...
S Johansson, L Wadsö, A Pilgård, G Alfredsen
Method for determining the critical moisture level for mould growth on building materials
2013 - IRG/WP 13-20530
The natural conditions of relative humidity (RH) and temperature (T) in different parts of a building is rarely constant over time. Instead, RH and T often vary cyclically and may pose a risk of mould growth as these conditions are the two key environmental parameters that controls mould growth. Consideration to both humidity and temperature conditions and the susceptibility to mould in a material...
A Ekstrand-Tobin, P Johansson, G Bok
Development of a rapid method to assess the rate of fungal colonization of wood
2013 - IRG/WP 13-20531
Testing of wood durability is today done mainly with accelerated exposure tests under rather realistic conditions (in ground, outdoors with moisture traps etc). Although such tests are accelerated with respect to the conditions that outdoor exposed wood structures are exposed to, they tend to take rather long time. The present paper presents the development of a rapid method intended to assess at ...
L Wadsö
Modelling the risk for mould growth on timber stored outdoors protected from rain
2013 - IRG/WP 13-20529
A mould resistance design (MRD) model was used to calculate the maximum duration of storage of timber outdoors under cover (protected from rain) before the onset of mould growth on the surface of wood. The prediction model is based on laboratory tests performed in constant and cyclic climates and were also confirmed against exposure tests in attics and crawl spaces. The prediction model presented ...
E Frühwald Hansson, S Bardage, S Thelandersson
Assessment of Scots pine sapwood susceptibility to moulds by determination of fungi growth and ergosterol content in infested wood
2014 - IRG/WP 14-20540
The susceptibility of wood to filamentous fungi (mould) attack is determine mainly by laboratory methods with descriptive grading of fungal growth on the surface of the wood specimens. It is a lot of different grading scale of fungi growth, but determination of the size of fungi growth is many times not easy, not clear and often difficult. Although the filamentous fungi are not included to microor...
A Fojutowski, A Koziróg, A Kropacz
A screening of factors that might influence the result of laboratory decay tests
2014 - IRG/WP 14-20548
Laboratory fungal decay tests provide important tools for performance testing of wood materials. But they are also hampered with some uncertainties regarding reproducibility. In addition to variation between fungal species and strains the test conditions are also believed to have some influence. The aim of this study was to screen the effect of a selection of test parameters that might influence t...
E Larnøy, G Alfredsen, A Treu, S Kolstad
Effect of silver nanoparticles on the rate of heat transfer to the core of the medium-density fiberboard mat
2014 - IRG/WP 14-40653
Effect of silver nanoparticles on the rate of heat transferred to the core section of medium-density fiberboard (MDF) mat was studied here. A 400 ppm aqueous nanosilver suspension was used at three consumption levels of 100, 150, and 200 mL/kg based on the weight of dry wood fibers; the results were then compared with the control MDF panels. The size range of silver nanoparticles was 30-80 nm. Res...
H Reza Taghiyari, O Schmidt, E Bari, P M Tahir, A Karimi, P Nouri, A Jahangiri
A guideline for sorting easy to impregnate Scots pine sapwood based on three treatability studies from Northern Europe
2014 - IRG/WP 14-40669
Scots pine sapwood is generally considered an easy to impregnate wood species, though it reportedly faces challenges towards a homogeneous impregnation and large variations in treatability are reported for the material.
This study comprises the results of three treatability tests that were performed on Scots pine (Pinus sylvestris) sapwood. The material impregnated was originated from a large ...
K Zimmer, E Larnøy, A Treu
The role of hydrophobins in surface growth by the Blue Stain fungi Aureobasidium pullulans
2015 - IRG/WP 15-10837
Hydrophobins are small proteins found exclusively in filamentous fungi. These proteins are able to assemble spontaneously into amphiphilic monolayers at hydrophobic–hydrophilic interfaces. Hydrophobins have a diverse role, e.g. allowing the fungi to break through interfaces during aerial hyphae formation, sporulation, fruit body production and cell penetration. In this ongoing study, we are look...
J Stenbæk, L Riber, J Blæsbjerg Nielsen, C Møller Hansen, B Jensen
Field Performance of Old-Growth and Second-Growth Western Red Cedar Fence Posts with and without Barrier Wraps
2015 - IRG/WP 15-10838
Many authors have suggested natural durability may be lower in second-growth western redcedar than in old-growth. One potential means of offsetting a decline in durability is use of physical barriers to separate the wood from soil. In the present work we compared the durability of old-growth and second-growth western red cedar posts, with and without barrier wraps, in a field test. After ten year...
P I Morris, J K Ingram, R Stirling
Investigations on the durability of several Congo basin wood species
2015 - IRG/WP 15-10840
The sawdust of ten wood species was studied to assess their natural resistance to decay. The extractives and lignin contents were primarily determined (between 2.7-16.0% and 26.8-35.9% respectively) to give an overview of the chemical distribution. Then, a phytochemical screening (colorimetric methods) characterized the different chemical functional groups in all extracts studied. Antioxidant act...
S Mounguengui, J-B Tchinda Saha, M Kor Ndikontar, S Dumarçay, C Attéké, D Perrin, E Gelhaye,
Effects of UV Radiation on Melanization and Growth of Fungi Isolated from Weathered Wood Surfaces
2015 - IRG/WP 15-10842
This research tests the hypothesis that fungi isolated from weathered wood will respond to elevated levels of UV radiation by increasing their melanin production. To test this hypothesis, we measured the melanin production and mycelial color of Aureobasidium pullulans and Cladosporium cladosporioides, before and after the fungi were grown under artificial UV, visible light and complete darkness. T...
V A Hernández, P D Evans
Development of a rapid screening method to determine the susceptibility to mould growth of novel construction and insulation products
2015 - IRG/WP 15-20562
Wood-based materials are commonly used in building construction/insulation as a replacement for solid timber. However, these materials are susceptible to microbiological growth and different environmental conditions influence the vulnerability of wood-based materials. Moulds are a common problem found within homes and cause aesthetic damage, health problems and can increase material vulnerability ...
B K Stefanowski, S F Curling, E Mansour, G A Ormondroyd
Interaction between Aspergillus niger fungus and other filamentous fungi on salt-agar medium and their growth on natural wood and wood treated with fungicide
2015 - IRG/WP 15-20569
Aspergillus niger (An) is very often used alone or in mixture with other filamentous fungi of the genus in testing biocides in disinfection procedures, safety, hygiene, medical fields as well as for testing resistance of wood and wood-based materials to moulds. Softwood species as well as hardwood are overgrown with An fungus very easily, causing drop of mainly the aesthetic value of wood product....
A Fojutowski, A Kropacz, A Koziróg
Building solid foundations to support market growth of preserved wood in the UK – treatment quality, product approval and the largest national field trial of preservative treated wood in 50 years
2015 - IRG/WP 15-30662
The Wood Protection Association (WPA) has just commissioned Britain’s largest ever durability trial of home grown timber, having contracted Building Research Establishment (BRE) to conduct a long term controlled field trial of sawn and pressure treated British Softwood posts at two sites with differing soil conditions. This large scale Field Trial is the last of an innovative and substantial thr...
E Suttie, G Ewbank
Mould growth on spruce claddings and the effect of selected influencing factors after 4 years of outdoor testing
2015 - IRG/WP 15-30671
Norway spruce (Picea abies) is the most frequently chosen wood species as claddings in façades in Norway, and is used both coated and uncoated. The visual changes that occur during weathering can be colour changes, abrasion or wear, blistering, flaking, and even cracks in the wood or coating, but more often growth of mould and blue stain fungi is the main challenge. A field test with synchronous monitoring of relative humidity, air temperature, material temperature and wood moisture content in Norway spruce claddings has been performed in southern Norway as part of the ClimateLife project. Visual evaluation of blue stain and mould growth according to EN 927-3 was performed, and evaluation data after 46 months exposure is presented. The objectives were to study the effect of 1) environment, 2) cardinal direction and 3) colour of the coated surface on growth of blue stain and mould fungi and to study the variation in relative humidity, air temperature, wood moisture content and material temperature. After 46 months exposure, the red coating system had generally the lowest mould ratings and the uncoated claddings had the highest. Of the white coloured claddings the ones facing south had lower mould ratings than those facing north, but the opposite were found for red coloured claddings. The relative humidity was higher in front of claddings exposed northwards and in a shaded environment compared to an open environment against south. In an open environment red coloured claddings had the lowest wood moisture content and highest material temperature, and red coloured claddings against south had the highest maximum material temperature.
L Ross Gobakken, G I Vestøl