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Lin, C.-F., Karlsson, O., Mantanis, G. I. & Sandberg, D. (2020). Fire performance and leach resistance of pine wood impregnated with guanyl-urea phosphate/boric acid and a melamine-formaldehyde resin. European Journal of Wood and Wood Products, 78(1), 107-111
Open this publication in new window or tab >>Fire performance and leach resistance of pine wood impregnated with guanyl-urea phosphate/boric acid and a melamine-formaldehyde resin
2020 (English)In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 78, no 1, p. 107-111Article in journal (Refereed) Published
Abstract [en]

Scots pine (Pinus sylvestris L.) wood impregnated with guanyl-urea phosphate/boric acid and a melamine-formaldehyde resin exhibited considerably increased resistance to leaching, while sustaining superior fire retardancy as tested by the limiting oxygen index (LOI) method. It was found that guanyl-urea phosphate has been well trapped in the wood structure by the cured resin network as evidenced by FTIR spectroscopy. Markedly, weight percentage gain (WPG) losses of fire retardant as low as 7.4% were achieved after excessive leaching of treated wood (EN 84). This was attributed to the effect of melamine-formaldehyde resin. Overall, this type of treatment could be a reliable method for producing fire-resistant pine wood for exterior uses.

Place, publisher, year, edition, pages
Springer, 2020
National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-78022 (URN)10.1007/s00107-019-01483-y (DOI)000511720000010 ()
Note

Validerad;2020;Nivå 2;2020-03-10 (johcin)

Available from: 2020-03-10 Created: 2020-03-10 Last updated: 2020-03-10Bibliographically approved
Neyses, B., Karlsson, O. & Sandberg, D. (2020). The effect of ionic liquid and superbase pre-treatment on the spring-back, set-recovery and Brinell hardness of surface-densified Scots pine. Holzforschung, 74(3), 303-312
Open this publication in new window or tab >>The effect of ionic liquid and superbase pre-treatment on the spring-back, set-recovery and Brinell hardness of surface-densified Scots pine
2020 (English)In: Holzforschung, ISSN 0018-3830, E-ISSN 1437-434X, Vol. 74, no 3, p. 303-312Article in journal (Refereed) Published
Abstract [en]

Compressing the surface of sawn timber results in a substantial increase in hardness, and this opens up new market opportunities of using low-density timber species as the raw material for high-value wood products. Unfortunately, widespread commercialisation is hindered by the lack of an industrially viable surface densification process, the major obstacle being the set-recovery (SR) of the densified wood cells upon exposure to moisture. Our hypothesis is that partial dissolution of the crystalline cellulose during densification will largely prevent the SR of densified wood. We therefore evaluated the effect of ionic liquid (IL) or organic superbase pre-treatment on the elastic spring-back (SB), SR and Brinell hardness (HB) of surface-densified wood. Specimens of Scots pine were treated with solutions of ILs or superbases, and then densified in a hot press at temperatures between 200°C and 270°C. The SR was reduced from 90% for the control group to only about 10% for the treated materials. The treated and densified specimens exhibited a higher HB than their untreated and densified counterparts. The method presented in this study is a precursor to the development of a continuous densification process adapted for an open system. Further studies are needed to understand the underlying mechanisms of the pre-treatment.

Place, publisher, year, edition, pages
Walter de Gruyter, 2020
Keywords
chemical treatment, surface modification, wood compression, wood modification
National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-75738 (URN)10.1515/hf-2019-0158 (DOI)000516773800007 ()2-s2.0-85073157805 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-03-31 (alebob)

Available from: 2019-08-29 Created: 2019-08-29 Last updated: 2020-03-31Bibliographically approved
Vaziri, M., Abrahamsson, L., Hagman, O. & Sandberg, D. (2020). Welding of wood in the presence of wollastonite. BioResources, 15(1), 1617-1628
Open this publication in new window or tab >>Welding of wood in the presence of wollastonite
2020 (English)In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 15, no 1, p. 1617-1628Article in journal (Refereed) Published
Abstract [en]

The use of wollastonite as a natural additive for the welding of Scots pine improved the water resistance and shear strength of the welded joint. The X-ray computed tomography images revealed that the welding of Scots pine with wollastonite could postpone crack formation in the welded joints. The specimens welded for a longer time (5 s) had a more uniform distribution of wollastonite particles in welded joints. The microstructure of the wood and the thickness of the wood cell walls also had a great influence on the thickness and strength of the welded joints. Water immersion tests showed that the use of wollastonite in wood joints was able to meet the requirement of resistance to frequent short-term and long-term exposure to water.

Place, publisher, year, edition, pages
NC State University, 2020
National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-78020 (URN)10.15376/biores.15.1.1617-1628 (DOI)000511129100112 ()
Note

Validerad;2020;Nivå 2;2020-03-10 (johcin)

Available from: 2020-03-10 Created: 2020-03-10 Last updated: 2020-03-10Bibliographically approved
Jones, D. & Sandberg, D. (2019). A review of wood modification across Europé as part of COST FP1407. In: Timber 2019: . Paper presented at Timber 2019, London, 3 - 4 Jul 2019 (pp. 107-112). Wood Technology Society, The Institute of Materials, Minerals and Mining, London
Open this publication in new window or tab >>A review of wood modification across Europé as part of COST FP1407
2019 (English)In: Timber 2019, Wood Technology Society, The Institute of Materials, Minerals and Mining, London , 2019, p. 107-112Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Wood Technology Society, The Institute of Materials, Minerals and Mining, London, 2019
National Category
Wood Science
Identifiers
urn:nbn:se:ltu:diva-76016 (URN)
Conference
Timber 2019, London, 3 - 4 Jul 2019
Available from: 2019-09-16 Created: 2019-09-16 Last updated: 2020-01-28
Myronycheva, O., Poohphajai, F., Sehlstedt-Persson, M., Vikberg, T., Karlsson, O., Junge, H. & Sandberg, D. (2019). Application of GRAS Compounds for the Control of Mould Growth on Scots Pine Sapwood Surfaces: Multivariate Modelling of Mould Grade. Forests, 10(9), Article ID 714.
Open this publication in new window or tab >>Application of GRAS Compounds for the Control of Mould Growth on Scots Pine Sapwood Surfaces: Multivariate Modelling of Mould Grade
Show others...
2019 (English)In: Forests, ISSN 1999-4907, E-ISSN 1999-4907, Vol. 10, no 9, article id 714Article in journal (Refereed) Published
Abstract [en]

Research Highlights: In this study, the Generally Recognised as Safe (GRAS) compounds were applied in order to study mould-fungi growth on dried Scots pine sapwood. Background and Objectives: The transition to the use of more sustainable wood-material may be possible by applying GRAS compounds that can control and prevent contamination by primary colonising mould fungi. Materials and Methods: Kiln-dried sawn timber was treated with three different GRAS compounds, and different fungal inoculation methods applied in order to investigate differences in the development of fungal communities. Results: Substances based on potassium silicate significantly reduced fungal growth and mould contamination on the studied wood surfaces. By combining wood-surface treatments with GRAS compounds, fungal-area size as predictors and mould grade as response, a partial least squares (PLS) model that makes it possible to predict mould grade on wood surfaces was developed. The PLS model is a key component in the development of a smart grading-systems equipped by e.g. high-speed digital cameras for the early detection of fungal attack on wood surfaces in different applications. However, the measurements based on chemical characterisation should be the next step to take in order significantly to enhance the model and increase the range of robust applications. In the current study, a multivariate model describing the influence of each fungal-covering area on mould grade was presented for the first time.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
bacteria, potassium silicate, N-Alkylbensyldimethylammonium chloride, wood, fungi, mould area, PLS modeling
National Category
Wood Science Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-75696 (URN)10.3390/f10090714 (DOI)000487978700070 ()2-s2.0-85072556439 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-08-27 (johcin)

Available from: 2019-08-26 Created: 2019-08-26 Last updated: 2020-01-28Bibliographically approved
Blomqvist, L., Berg, S. & Sandberg, D. (2019). Distortion in laminated veneer products exposed to relative-humidity variations: Experimental studies and finite-element modelling. BioResources, 14(2), 3768-3779
Open this publication in new window or tab >>Distortion in laminated veneer products exposed to relative-humidity variations: Experimental studies and finite-element modelling
2019 (English)In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 14, no 2, p. 3768-3779Article in journal (Refereed) Published
Abstract [en]

A shortcoming of the laminated bending process is that the product may become distorted after moulding. This study focused on the influence of fibre orientation deviation for individual veneers on the distortion of a moulded shell. The distortion of 90 cross-laminated shells of the same geometrical shape, consisting of seven peeled birch veneers, were studied under relative humidity variation. All the veneers were straight-grained in the longitudinal-tangential plane, but to simulate a deviation in fibre orientation, some of the individual veneers were oriented at an angle of 7° relative to the main orientation of the other veneers in the laminate. A finite element model (FEM) was applied to study the possibility of predicting the results of a practical experiment. The study confirms the well-known fact that deviation in fibre orientation influences shape stability. The results also show how the placement of the abnormal veneer influences the degree of distortion. From this basic knowledge, some improvements in the industrial production were suggested. However, the FE model significantly underestimated the results, according to the empirical experiment, and it did not show full coherence. The survey shows the complexity of modelling the behaviour of laminated veneer products under changing climate conditions and that there is a great need to improve the material and process data to achieve accurate simulations. Examples of such parameters that may lead to distortion are density, annual ring orientation in the cross section of the veneer, the orientation of the loose and tight sides of the veneer, and parameters related to the design of the moulding tool.

Place, publisher, year, edition, pages
North Carolina State Univ Dept Wood & Paper Sci, 2019
Keywords
Birch, Cup, FEM, Veneer, Wood, Twist
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-73340 (URN)10.15376/biores.14.2.3768-3779 (DOI)000466449000091 ()2-s2.0-85071081837 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-04-10 (oliekm)

Available from: 2019-03-28 Created: 2019-03-28 Last updated: 2020-01-28Bibliographically approved
Lin, C.-F., Karlsson, O., Mantanis, G. I. & Sandberg, D. (2019). Fire performance and leach resistance of pine wood impregnated with guanyl-urea phosphate (GUP)/boric acid (BA) and melamine-formaldehyde (MF) resin. In: Fredriksson M. (Ed.), Proceedings of the 15th Annual Meeting of the Northern European Network for Wood Science and Engineering - WSE2019,  Lund, Sweden, October  9-10: . Paper presented at 15th Annual Meeting of the Northern European Network for Wood Science and Engineering - WSE2019 (pp. 147-149). Lund: Lund University Open Access
Open this publication in new window or tab >>Fire performance and leach resistance of pine wood impregnated with guanyl-urea phosphate (GUP)/boric acid (BA) and melamine-formaldehyde (MF) resin
2019 (English)In: Proceedings of the 15th Annual Meeting of the Northern European Network for Wood Science and Engineering - WSE2019,  Lund, Sweden, October  9-10 / [ed] Fredriksson M., Lund: Lund University Open Access, 2019, p. 147-149Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Lund: Lund University Open Access, 2019
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-76392 (URN)
Conference
15th Annual Meeting of the Northern European Network for Wood Science and Engineering - WSE2019
Available from: 2019-10-14 Created: 2019-10-14 Last updated: 2020-01-28
Olofsson, L., Broman, O. & Sandberg, D. (2019). Holistic-Subjective Automatic Grading of Sawn Timber: Sensitivity to Systematic Changes. In: International Wood Machining Seminar: . Paper presented at International Wood Machining Seminar.
Open this publication in new window or tab >>Holistic-Subjective Automatic Grading of Sawn Timber: Sensitivity to Systematic Changes
2019 (English)In: International Wood Machining Seminar, 2019Conference paper, Published paper (Other academic)
Abstract [en]

Holistic-subjective automatic grading of sawn timber by a partial least squares (PLS) regression model required training of the model. This study tests the sensitivity towards systematic changes of a specialized PLS model, trained on a selected type of material suitable for a specific paneling product, when used to grade sawn timber systematically different than the material it was trained on. A sawmills automatic scanning system used cameras to measure knot and bark features on 900 planks. Each plank was split into three boards, and each board was shaped into an indoor paneling product and manually graded as desirable or undesirable at a planing mill. The plank grade was decided as the majority of the board-grade outcome. The knot and bark measurements were used to create a large set of feature variables for each plank that was correlated to the plank’s grade by PLS regression. Of the 900 available planks, 434 planks sawn from top logs were used as a class-balanced specialistic training set, with half of the planks resulting in a majority of desirable boards. The regression model trained on the class-balanced specialistic training set was used to grade a test set of 282 planks, containing 64 planks that by manual classification of automatically captured images were determined to be sawn from butt logs and were systematically different from the training material. The PLS model’s grading accuracy of the planks sawn from top logs was 76%, compared to 70% for the plank sawn from butt logs. The grading outcome resulted in a higher proportion of both delivered planks from the sawmill and received desirable planks by the planing mill when grading planks from top logs as compared to planks from butt logs. The results indicated that a specialistic PLS model should not be used for a generalistic use-case.

Keywords
sawmilling, wood, automatic grading, PLS-regression
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-74170 (URN)
Conference
International Wood Machining Seminar
Available from: 2019-06-04 Created: 2019-06-04 Last updated: 2020-01-28
Olofsson, L., Broman, O. & Sandberg, D. (2019). Holistic-subjective automatic grading of sawn timber: Sensitivity to systematic changes.. In: Schajer, G (Ed.), Proceedings of the 24th International Wood Machining Seminar, IWMS 24.: . Paper presented at IWMS 24. August 25-30, 2019, Corvallis, Oregon, USA (pp. 154-167). Corvallis: Oregon State University (OSU)
Open this publication in new window or tab >>Holistic-subjective automatic grading of sawn timber: Sensitivity to systematic changes.
2019 (English)In: Proceedings of the 24th International Wood Machining Seminar, IWMS 24. / [ed] Schajer, G, Corvallis: Oregon State University (OSU) , 2019, p. 154-167Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Corvallis: Oregon State University (OSU), 2019
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-76021 (URN)
Conference
IWMS 24. August 25-30, 2019, Corvallis, Oregon, USA
Available from: 2019-09-16 Created: 2019-09-16 Last updated: 2020-01-28
Kim, I., Karlsson, O., Jones, D. & Sandberg, D. (2019). Maleic anhydride and sodium hypophosphite as a potential wood modification system. In: Fredriksson M (Ed.) (Ed.), Proceedings of the 15th Annual Meeting of the Northern European Network for Wood Science and Engineering - WSE2019,  Lund, Sweden, October  9-10, pp. 28-30: . Paper presented at 15th Annual Meeting of the Northern European Network for Wood Science and Engineering - WSE2019 (pp. 28-30). Lund: Lund University Open Access
Open this publication in new window or tab >>Maleic anhydride and sodium hypophosphite as a potential wood modification system
2019 (English)In: Proceedings of the 15th Annual Meeting of the Northern European Network for Wood Science and Engineering - WSE2019,  Lund, Sweden, October  9-10, pp. 28-30 / [ed] Fredriksson M (Ed.), Lund: Lund University Open Access, 2019, p. 28-30Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Lund: Lund University Open Access, 2019
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-76391 (URN)
Conference
15th Annual Meeting of the Northern European Network for Wood Science and Engineering - WSE2019
Available from: 2019-10-14 Created: 2019-10-14 Last updated: 2020-01-28
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-4526-9391

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