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| 2. |
- Alfredsen, Gry, et al.
(författare)
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New insight regarding mode of action of brown rot decay of modified wood based on DNA and gene expression studies : A review
- 2015
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Ingår i: International Wood Products Journal. - 2042-6445 .- 2042-6453. ; 6:1, s. 5-7
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Tidskriftsartikel (refereegranskat)abstract
- Modified wood shows resistance against wood deteriorating fungi, but the mechanisms are still not fully understood. The aim of this paper was to summarise the molecular studies performed on modified wood with regard to brown rot decay fungi. The DNA data showed that fungi are present inside the laboratory wood test samples already after two weeks of inoculation. Generally the fungal DNA content reflects mass loss and wood moisture content. The oxidative gene expression seems to be higher in modified wood than in untreated wood and it tend to increase during incubation. Based on the gene expression data we suggest that the hypothesis of lack of substrate recognition by the fungus should be rejected. In the reviewed studies, total wood moisture content in the samples was generally not low enough to inhibit fungal colonisation. Hence, moisture distribution within the wood should be studied more closely.
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| 3. |
- Avez, Coralie, et al.
(författare)
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Large-diameter single dowel joint : finite element modelling of a reinforced joint
- 2017
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Ingår i: International Wood Products Journal. - : Informa UK Limited. - 2042-6445 .- 2042-6453. ; 8:sup1, s. 50-56
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Tidskriftsartikel (refereegranskat)abstract
- Finding new efficient connectors or improving existing ones are important issues in timber construction. This research investigates an innovative large-diameter dowel-type connection by using a finite elements model calibrated with experimental results. This connection is made of a large-diameter single dowel reinforced by means of a steel plate with a vulcanised rubber layer. The steel plate shape, thickness and dimensions, the rubber stiffness, the steel mechanical properties, etc., are parameters that may influence the critical load of the plate. The joint load-bearing capacity is also highly depending on the load direction to the grain. Those parameters are investigated using FE modelling and discussed in order to propose design recommendations.
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| 4. |
- Blomqvist, Lars, 1962-
(författare)
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Shape stability of laminated veneer products : a review – defining and achieving shape stability
- 2015
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Ingår i: International Wood Products Journal. - : Taylor & Francis. - 2042-6445 .- 2042-6453. ; 6:2, s. 89-95
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Tidskriftsartikel (refereegranskat)abstract
- Laminated veneer products (LVPs) consist of veneers bonded together with an adhesive into a predetermined shape. Deviation from the intended shape is a problem for both manufacturers and customers of the final products. The shape stability of LVP depends on a variety of material and process parameters, and this review identifies several important factors that influence shape stability, the purpose being to find ways of decreasing distortion and improving shape stability so that product quality can be improved.The review ends to the following statements:The fibre orientation of the veneer strongly influences the shape stability of LVP. The products can show considerable distortion (particularly twist) if the fibre orientation of the veneer is oriented in an unsuitable way in the assembly before moulding.The effect of fibre orientation on shape stability can be very small directly after moulding, but it can increase considerably when the moulded product is subjected to a change in moisture content (MC). In general, a change in moisture leads to distortion. Moisture changes alone, however, result in a controlled distortion.The orientation of the loose and tight sides of the veneers in LVP affects the shape stability.An asymmetrical construction, coupled with different levels of moisture in the different veneers in an assembly before moulding, will result in poor shape stability of the product.The choice of wood species affects shape stability. Beech shows more distortion and poorer shape stability than birch.Based on existing knowledge to produce shape-stable LVP, the veneers should be conditioned to uniform MC and sorted with regard to fibre orientation and loose or tight side of the veneer before bonding. End-user climates should govern the veneers’ MC and added moisture from the adhesive during the process. Straight grain veneers and symmetry should always be sought.This review reveals several areas that need to be further clarified in order to achieve shape-stable LVP, for example the influence of adhesive, the distribution of pressure, temperature, stresses and strains during moulding and the development of numerical methods to better predict the final shape.
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| 5. |
- Böger, Thomas, et al.
(författare)
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Binderless boards made of milled coconut husk: an analysis of the technical feasibility and process restraints
- 2018
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Ingår i: International Wood Products Journal. - : Informa UK Limited. - 2042-6445 .- 2042-6453. ; 9:1, s. 3-8
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Tidskriftsartikel (refereegranskat)abstract
- The possibility of producing binderless panels made of milled coconut husk, a largely available by-product of the coconut oil industry, has been shown in previous researches. Long pressing times and a high risk of blisters have however hindered the industrial implementation of the process. In this study, a more energy-efficient manufacturing process, involving a tailored degassing step, was developed on a laboratory scale and then validated at an industrial size (2 x 1 m(2)). To achieve mechanical properties close to the European and Japanese standards for fibreboards and to avoid the delamination of the boards, final densities between 900 and 1000 kg m(-3) had to be targeted. Similarly, a successful board production was only possible if the moisture content of the husk was between 10 and 25%. The need for a suitable mat-forming technology to avoid the risk of warping of the panel was highlighted.
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| 6. |
- Ehmcke, Gabriele, et al.
(författare)
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Improvement of a method for topochemical investigations of degraded furfurylated wood
- 2016
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Ingår i: International Wood Products Journal. - : Informa UK Limited. - 2042-6445 .- 2042-6453. ; 7:2, s. 96-101
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Tidskriftsartikel (refereegranskat)abstract
- Today there is an increasing demand for wood protection systems which are based on low environmental impact technologies. The aim of this study was to improve a method for investigating furfurylated Pinus radiata, both in terms of the furfuryl alcohol polymerisation process in the wood cell wall and the detection of initial signs of brown rot degradation. It is an established theory today that brown rot degradation starts with lignin modification in the outermost part of the secondary cell wall and the combined middle lamella. We adapted a method (cellular UV microspectrophotometry, UMSP) which enables direct imaging of the lignin distribution and modification within individual cell wall layers. Furfurylated P. radiata, incubated with Postia placenta, were scanned with monochromatic UV-light at 280 nm. The results showed that USMP is a promising method to study furfurylated wood and early fungal degradation damages in the cell wall of furfurylated wood.
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| 7. |
- Fredriksson, Maria, et al.
(författare)
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The cell wall composition of Norway spruce earlywood and latewood revisited
- 2018
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Ingår i: International Wood Products Journal. - : Informa UK Limited. - 2042-6445 .- 2042-6453. ; 9:2, s. 80-85
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Tidskriftsartikel (refereegranskat)abstract
- The xylem of gymnosperm trees consists mainly of tracheids, which generally have larger radial diameters and thinner walls in earlywood than in latewood. Information on possible chemical differences is limited, but according to a few studies, earlywood normally contains more lignin relative to cellulose than latewood. However, for methods giving results per gram dry matter, this result is expected since a larger part of the earlywood cell wall material consists of lignin-rich middle lamella. In this study, we used Raman microspectroscopy to assess relative biopolymer composition of earlywood and latewood secondary cell walls from mature sapwood of Norway spruce (Picea abies (L.) Karst.). In addition, infrared spectroscopy of isolated earlywood and latewood from the same growth rings as well as additional growth rings was performed. Both methods showed significantly higher relative lignin content in the earlywood which confirms results from earlier studies.
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| 8. |
- Gong, Peichen
(författare)
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The impact of international efforts to reduce illegal logging on the global trade in wood products
- 2018
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Ingår i: International Wood Products Journal. - : Informa UK Limited. - 2042-6445 .- 2042-6453. ; 9, s. 28-38
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Tidskriftsartikel (refereegranskat)abstract
- Illegal logging has become a global issue because of its adverse effects on biodiversity and climate change. In order to reduce illegal logging, many countries around the world have introduced regulations for the international trade of forest products. This paper examines the effects of these efforts on international trade of forest products. The analysis is conducted using the Heckscher-Ohlin-Vanek model, where the number of regulations against illegal logging is used to describe the level of efforts, and is included as an explanatory variable for national net export of forest products. The results show that efforts against illegal logging have had significant and positive impacts on the net export of forest products.
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| 9. |
- Jockwer, Robert, et al.
(författare)
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Impact of knots on the fracture propagating along grain in timber beams
- 2017
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Ingår i: International Wood Products Journal. - : Informa UK Limited. - 2042-6445 .- 2042-6453. ; 8:sup1, s. 39-44
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Tidskriftsartikel (refereegranskat)abstract
- Fracture propagating along the grain of timber is one of the most relevant failure mechanisms due to the wood’s low strength and its brittle failure behaviour when subjected to excessive shear and tensile stresses perpendicular to the grain. According to the current procedures, the fracture energy of wood is determined on small clear specimens. However, for the prediction of the structural behaviour of full-scale structural timber members, the influence of knots has to be accounted for. The discrepancy between the fracture behaviour of small specimens and members of structural size has already been observed in several studies. The aim of this paper is to provide a review on a selection of these studies and to discuss their relevancy for the evaluation of the fracture properties and the structural behaviour of full-scale structural timber.
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| 10. |
- Karunasekera, Hasanthi, et al.
(författare)
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Phylogenic, molecular and decay analysis of Phialophora species causing soft rot of wood
- 2015
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Ingår i: International Wood Products Journal. - : Informa UK Limited. - 2042-6445 .- 2042-6453. ; 6, s. 189-197
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Tidskriftsartikel (refereegranskat)abstract
- Soft rot decay of treated wood in ground contact and loss of service-life remains an important economic issue worldwide. This study determined the identity of unclassi (204-1, 35-1, TS4M3, 25M3) isolated from wood in-service. Phylogenetic analysis clustered strains into a single clade homologous with internal transcribed spacer (ITS) rDNA showed minor differences at single bases for strains 35-1 and 25M3. Compatibility occurred between TS4M3, 25M3 and 204-1 but not 35-1, lagerbergii with strain 35-1 least aggressive. Light microscopy showed Type I diffuse soft rot cavity formation reminiscent of TS4M3, 25M3 and 204-1 but always less for 35-1. Strains 35-1 and TS4M3 showed highest Cutolerance on CuSO indicate the homology and decay morphology, although considerable intra-variation exists.fied Phialophora strainsPhialocephala dimorphospora. Sequencing ofPhialophoraor Phialophora botulispora. Birch was more rapidly degraded than pine for all strains,P. dimorphospora. Growth rates at 15, 20 and 26°C were similar for4 and micronized copper incorporated into malt extract agar plates. Results indicate the Phialophora spp. A strains represent P. dimorphospora as suggested by strong strong homology and decay morphology, although considerable intra-variation exists.
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