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Vikberg, T. & Hansson, L. (2024). Exploring the Potential of CT Image Processing Analysis for Assessing Capillary Flow in Pine Wood Logs. Pro Ligno (1), 3-8
Open this publication in new window or tab >>Exploring the Potential of CT Image Processing Analysis for Assessing Capillary Flow in Pine Wood Logs
2024 (English)In: Pro Ligno, ISSN 1841-4737, E-ISSN 2069-7430, no 1, p. 3-8Article in journal (Refereed) Published
Abstract [en]

This research delves into the unexplored territory of using CT image processing techniques to assess capillary flow in freshly felled Scotch pine logs during the drying process. Leveraging a high-resolution CT scanner, the study captures intricate details of the wood’s internal structure, which were then quantified using image processing algorithms. The findings confirm the efficacy of CT image processing in accurately determining capillary flow in wood. This opens up new opportunities for non-destructive testing methods and contributes to a deeper understanding of wood properties. The implications of these findings are farreaching, offering substantial advancements in quality control and processing optimization in the wood industry.

Place, publisher, year, edition, pages
Transilvania University Press Brasov, 2024
Keywords
CT scanning, image processing, capillary flow, pine log
National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-105242 (URN)
Note

Validerad;2024;Nivå 1;2024-05-02 (hanlid);

Full text license: "All content is freely available without charge to any user or his/her institution. Users are allowed to read, download, copy, distribute, print, search, or link to the full texts of the articles in this journal without asking prior permission from the publisher or the author."

Available from: 2024-04-25 Created: 2024-04-25 Last updated: 2024-05-14Bibliographically approved
Hajiyan, E., Couceiro, J., Hansson, L. & Sandberg, D. (2023). Drying Behaviour of Western Hemlock with Schedules Developed for Norway Spruce and Scots Pine. Paper presented at 13th International Conference Wood Science and Technology in the Third Millennium, ICWSE 2023, November 2 – 4, 2023, Brasov, Romania. Applied Sciences, 13(19), Article ID 11083.
Open this publication in new window or tab >>Drying Behaviour of Western Hemlock with Schedules Developed for Norway Spruce and Scots Pine
2023 (English)In: Applied Sciences, E-ISSN 2076-3417, Vol. 13, no 19, article id 11083Article in journal (Refereed) Published
Abstract [en]

Determining moisture content (MC) distribution during the drying of porous materials such as wood is crucial for developing drying schedules and assessing their suitability to achieve optimised processes. This study aimed to determine the causes of the unique drying behaviour and the well-known unusual longer drying time of western hemlock compared to other similar softwoods. In situ X-ray computed tomography (CT) was used to study the evolution of MC in timber during the drying process. The drying behaviour of western hemlock (Tsuga heterophylla (Raf.) Sarg.) was compared with Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) from green to oven-dried condition with industry-proposed drying schedules used for steering a custom-made experimental kiln combined with a CT scanner. CT scanning was performed at 30 min intervals during the complete drying period of 30 h, and the CT images were processed to calculate the MC evolution within the specimen. Western hemlock showed a considerably slower capillary-phase drying and did not go into the transition and diffusion phases when a schedule adapted to pine and spruce drying was applied for its drying. CT images and MC gradient calculations showed a lower drying rate and severe non-uniformity in MC distribution, which could be due to the effect of higher green MC and the presence of wet pockets. Furthermore, the evaporation front at the first 5 h of drying receded faster into the hemlock specimen, and as drying proceeded, it slowed down compared to other specimens.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
CT scan, experimental research, image processing, moisture content, porous material, timber drying, wet pockets
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-101641 (URN)10.3390/app131911083 (DOI)001086948100001 ()2-s2.0-85174184849 (Scopus ID)
Conference
13th International Conference Wood Science and Technology in the Third Millennium, ICWSE 2023, November 2 – 4, 2023, Brasov, Romania
Note

Godkänd;2023;Nivå 0;2023-10-12 (joosat);Konferensartikel i tidskrift;

Part of special Issue: International Conference Wood Science and Engineering in the Third Millennium - ICWSE 2023

CC BY 4.0 License

Available from: 2023-10-12 Created: 2023-10-12 Last updated: 2024-03-11Bibliographically approved
Couceiro, J., Lin, C.-f., Hansson, L., Schleicher, F., Svensson, M., Jones, D., . . . Sandberg, D. (2023). Use of X-ray computed tomography for real-time studies of the fire progress in wood. Wood Material Science & Engineering, 18(6), 2150-2152
Open this publication in new window or tab >>Use of X-ray computed tomography for real-time studies of the fire progress in wood
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2023 (English)In: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 18, no 6, p. 2150-2152Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Taylor & Francis, 2023
National Category
Building Technologies Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-102323 (URN)10.1080/17480272.2023.2269539 (DOI)2-s2.0-85176144315 (Scopus ID)
Projects
CT WOOD
Funder
Luleå University of Technology
Note

Validerad;2024;Nivå 2;2024-03-22 (hanlid)

Available from: 2023-11-06 Created: 2023-11-06 Last updated: 2024-03-22Bibliographically approved
Rodrigues, Q., Huber, J. A., Hansson, L., Mensah, R. A. & Moutou Pitti, R. (2023). Using X-Ray Computed Tomography To Measure Fire Degradation Of A Timber Connection. In: Nyrud, A. Q.; Malo, K. A.; Nore, K. (Ed.), World Conference on Timber Engineering (WCTE 2023): Timber for a Livable Future. Paper presented at 13th World Conference on Timber Engineering 2023 (WCTE 2023), Oslo, Norway, June 19-22, 2023 (pp. 1519-1525). Oslo: World Conference on Timber Engineering 2023 (WCTE 2023)
Open this publication in new window or tab >>Using X-Ray Computed Tomography To Measure Fire Degradation Of A Timber Connection
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2023 (English)In: World Conference on Timber Engineering (WCTE 2023): Timber for a Livable Future / [ed] Nyrud, A. Q.; Malo, K. A.; Nore, K., Oslo: World Conference on Timber Engineering 2023 (WCTE 2023) , 2023, p. 1519-1525Conference paper, Published paper (Refereed)
Abstract [en]

The charring behaviour of timber elements under fire is well understood, however, the effects of fire and heat on connections are not equally well known. Timber connections often use steel fasteners, like screws or angle brackets, which conduct heat much better than wood. Moreover, these fasteners lose their mechanical resistance and capacity under elevated temperatures. X-ray computed tomography (CT) can be used to reconstruct the internal structure of wood non-destructively. It should therefore be possible to use this technology to also study the progressive degradation due to fire of a timber connection. The goal of the present study is to investigate how CT can be used to analyse the degradation of a timber connection due to fire. Samples of Norway spruce with self-tapping screws were scanned before and after a fire exposure, and mechanical tests were performed. The results indicate that the degradation due to fire in a timber connection can be observed in CT scans, but that certain measures need to be taken to minimise the effects of image artefacts due to X-ray scattering and photon starvation.

Place, publisher, year, edition, pages
Oslo: World Conference on Timber Engineering 2023 (WCTE 2023), 2023
Keywords
Steel-to-timber fastener, CT, Image artefacts, Image analysis, Density, Charring
National Category
Wood Science Building Technologies
Research subject
Wood Science and Engineering; Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-99213 (URN)10.52202/069179-0206 (DOI)2-s2.0-85172697721 (Scopus ID)
Conference
13th World Conference on Timber Engineering 2023 (WCTE 2023), Oslo, Norway, June 19-22, 2023
Note

ISBN för värdpublikation: 9781713873273, 9781713873273

Available from: 2023-07-17 Created: 2023-07-17 Last updated: 2023-11-30Bibliographically approved
Couceiro, J., Hansson, L., Mannes, D., Niemz, P. & Sandberg, D. (2022). Estimation of the moisture content in wood by combination of Neutron and X-ray imaging. In: Wang, X., Ross, R.J. (Ed.), Proceedings: 22nd International Nondestructive Testing and Evaluation of Wood Symposium: . Paper presented at 22nd International Nondestructive Testing and Evaluation of Wood Symposium, Quebec City, Quebec, Canada, May 24-27, 2022 (pp. 40-47). Madison (WI), USA: United States Department of Agriculture
Open this publication in new window or tab >>Estimation of the moisture content in wood by combination of Neutron and X-ray imaging
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2022 (English)In: Proceedings: 22nd International Nondestructive Testing and Evaluation of Wood Symposium / [ed] Wang, X., Ross, R.J., Madison (WI), USA: United States Department of Agriculture , 2022, p. 40-47Conference paper, Published paper (Other academic)
Place, publisher, year, edition, pages
Madison (WI), USA: United States Department of Agriculture, 2022
Series
United States Department of Agriculture General Technical Report FPL-GTR-290
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-91091 (URN)
Conference
22nd International Nondestructive Testing and Evaluation of Wood Symposium, Quebec City, Quebec, Canada, May 24-27, 2022
Available from: 2022-06-08 Created: 2022-06-08 Last updated: 2022-10-28Bibliographically approved
Couceiro, J., Hansson, L., Sandberg, D. & Ursella, E. (2022). Industrial CT scanning in wood research. In: Wang, X., Ross, R.J. (Ed.), Proceedings: 22nd International Nondestructive Testing and Evaluation of Wood Symposium: . Paper presented at 22nd International Nondestructive Testing and Evaluation of Wood Symposium, Quebec City, Quebec, Canada, May 24-27, 2022 (pp. 17-17). Madison (WI), USA: United States Department of Agriculture
Open this publication in new window or tab >>Industrial CT scanning in wood research
2022 (English)In: Proceedings: 22nd International Nondestructive Testing and Evaluation of Wood Symposium / [ed] Wang, X., Ross, R.J., Madison (WI), USA: United States Department of Agriculture , 2022, p. 17-17Conference paper, Oral presentation with published abstract (Other academic)
Place, publisher, year, edition, pages
Madison (WI), USA: United States Department of Agriculture, 2022
Series
United States Department of Agriculture General Technical Report FPL-GTR-290
National Category
Wood Science
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-91089 (URN)
Conference
22nd International Nondestructive Testing and Evaluation of Wood Symposium, Quebec City, Quebec, Canada, May 24-27, 2022
Available from: 2022-06-08 Created: 2022-06-08 Last updated: 2022-06-13Bibliographically approved
Huber, J. A., Broman, O., Oja, J., Hansson, L. & Ekevad, M. (2022). Nondestructive Testing of Timber Prior to Sawing Using Finite Element Models Based on X-ray Computed Tomography Data - A Preliminary Study. In: Wang, Xiping; Ross, Robert J. (Ed.), Proceedings: 22nd International Nondestructive Testing and Evaluation of Wood Symposium: . Paper presented at 22nd International Nondestructive Testing and Evaluation of Wood Symposium, Quebec City, Quebec, Canada, May 24-27, 2022 (pp. 200-200). Madison, WI, USA: United States Department of Agriculture
Open this publication in new window or tab >>Nondestructive Testing of Timber Prior to Sawing Using Finite Element Models Based on X-ray Computed Tomography Data - A Preliminary Study
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2022 (English)In: Proceedings: 22nd International Nondestructive Testing and Evaluation of Wood Symposium / [ed] Wang, Xiping; Ross, Robert J., Madison, WI, USA: United States Department of Agriculture , 2022, p. 200-200Conference paper, Oral presentation with published abstract (Other academic)
Abstract [en]

X-ray computed tomography (CT) of wood delivers internal density data of a scanned object, where, depending on the resolution, internal features like the pith, annual rings and knots can be identified. Some sawmills use CT scanners in front of the saw line to determine the optimal positioning of the log in the saw, to maximise the value yield of the sawn products. We envision that the gathered CT data also could be used for mechanical evaluations of the timber using numerical models of boards prior to sawing. In a recent study by the authors, a method was developed to create 3D and 1D finite element (FE) models based on CT scans of dried sawn timber, which could predict bending stiffness and strength in bending simulations with high accuracy. The objective of the present study is to explore how the method can be adapted to CT scans of logs before sawing. Our preliminary study was based on CT data of green Norway Spruce logs and the corresponding scans of dried sawn timber. The stiffness and strength were evaluated using four-point bending tests. Additionally, the resonance frequency of the logs was recorded. The corresponding volume of each piece of sawn timber was extracted from the log data and an FE model was created. The model accounted for the pith, the annual rings, the knots, and the local fibre deviations around knots. Various laws for local stiffness and different failure criteria were tested. The study showed how FE models of virtual pieces of sawn timber can be created from CT data and what obstacles need to be overcome for further development of the presented method. The results indicated that more detailed evaluations of the relationship between local stiffness and density may be required, in specific for knots and for wood in green state.

Place, publisher, year, edition, pages
Madison, WI, USA: United States Department of Agriculture, 2022
Series
United States Department of Agriculture General Technical Report FPL-GTR-290
Keywords
strength prediction, virtual grading, numerical modelling, sawmill optimisation
National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-91274 (URN)
Conference
22nd International Nondestructive Testing and Evaluation of Wood Symposium, Quebec City, Quebec, Canada, May 24-27, 2022
Projects
ReadIStrength
Available from: 2022-06-12 Created: 2022-06-12 Last updated: 2022-06-13Bibliographically approved
Couceiro, J., Sehlstedt-Persson, M. & Hansson, L. (2021). Kapillärt vattenupptag tvärs fibrerna i KL‐trä – Studier i CT: Slutrapport. Skellefteå: Luleå tekniska universitet
Open this publication in new window or tab >>Kapillärt vattenupptag tvärs fibrerna i KL‐trä – Studier i CT: Slutrapport
2021 (Swedish)Report (Other academic)
Abstract [en]

The project aimed to study capillary water and moisture absorption through diffusion in spruce boards across fiber direction when exposed to liquid water for 168 h, as well as the drying after that. The study was driven by the necessity of fulfilling the HusAMA YSC.122 rule that states that the surface MC of the wood must not be above 18 % when it is built in and above 16 % if surface treatment will be done. CT scanning was used to study changing MC levels in 2.25 mm layers from the wood surface as average values for each layer. The layers are named after the deepest section of the layer i.e. layer 4.5 is between 2.25 mm and 4.5 mm.

Water uptake: Results of the studies show that liquid water can penetrate down to 4.5 mm (MC >30%), even though in most cases it does not penetrate beyond 2.25 mm (surface layer). Local pockets or higher MC may nevertheless occur. None of the specimens shows liquid water penetration beyond the surface layer within the first 72 h of liquid water exposure. Neither density nor board side exposed (pith‐side or sapwood‐side) have an influence in the rate of liquid water/moisture absorption. Regarding the 18% limit established by HusAMA YSC.122, it can be reached within the first 24 hours of exposure, but its penetration is limited to around 6.75 mm of depth. Regarding the 16 % limit, a more heterogeneous behavior among specimens can be seen, with penetrations that go from 13.5 mm to 20.25 mm after 24 h of exposure.

Drying: Drying took place by samples kept in room climate in the lab with no climate control or air‐velocity regulation. The conditions were equivalent to EMC of 6 %. All layers of the wood specimens are below 18 % within 48 h when water is removed after 168 h of exposure. The 16 % limit can take from 48 to up to 140 h to be reached by all layers in the atmospheric conditions of the lab, which at the moment of the experiment were extremely dry. This factor must be taken into account when interpreting results of this experiment not only during drying, but also during water uptake. 

Place, publisher, year, edition, pages
Skellefteå: Luleå tekniska universitet, 2021. p. 24
Series
TräCentrumNorr
Keywords
trä, CT, tomograf, kapillärt vattenupptag, KL-trä
National Category
Wood Science
Research subject
Wood Science and Engineering; Centre - WoodCenter North (TCN)
Identifiers
urn:nbn:se:ltu:diva-72971 (URN)
Funder
European Regional Development Fund (ERDF)Region Västerbotten
Available from: 2021-03-31 Created: 2021-03-31 Last updated: 2023-09-05Bibliographically approved
Couceiro, J., Hansson, L. & Sandberg, D. (2019). Dual-Energy X-Ray Absorptiometry for Measuring Moisture Content in Wood: Is It Possible?. In: Proceedings: 21st International Nondestructive Testing and Evaluation of Wood Symposium Freiburg, Germany 2019. Paper presented at 21st International Nondestructive Testing and Evaluation of Wood Symposium, 24-27 September, 2019, Freiburg, Baden-Württemberg, Germany (pp. 292-292). United States Department of Agriculture
Open this publication in new window or tab >>Dual-Energy X-Ray Absorptiometry for Measuring Moisture Content in Wood: Is It Possible?
2019 (English)In: Proceedings: 21st International Nondestructive Testing and Evaluation of Wood Symposium Freiburg, Germany 2019, United States Department of Agriculture , 2019, p. 292-292Conference paper, Oral presentation with published abstract (Other academic)
Abstract [en]

Medical computer tomography (CT) uses dual-energy x-ray absorptiometry (DXA) for basis material differentiation. DXA is based on the different interactions between x-ray photons and the scanned material based on the energy of the x ray, the effective atomic number of the material components, and their electron density. Considering wood and water as the only components of a wood specimen at a given moisture content (MC), DXA has been suggested for quantification of the wood-water proportion and thus for the determination of MC. Such an approach can provide great improvements and advantages in the use of CT technology in the sawmill industry, for example, detection of fresh knots in sapwood and optimization of timber drying. However, the approach in wood science is recent and still presents doubts. This study tries to clarify the possibilities of dual-energy CT for estimation of moisture in wood through the approach of the ratio method, which has been used as the theoretical basis for establishing the feasibility of the DXA in wood science and which is often used for differentiation between components of a scanned material. Two-dimensional x-ray measurements were confronted with theoretical calculations. The theoretical calculations show that the attenuation of water and wood at different acceleration voltages differs enough to apply the ratio method, but the practical experiments cannot prove it. The authors suggest that the inhomogeneity in wood introduces large errors that cause misleading results. Also, the equipment providing measurements of photon count could present different results.

Place, publisher, year, edition, pages
United States Department of Agriculture, 2019
Keywords
wood moisture content, dual-energy x-ray absorptiometry
National Category
Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-76390 (URN)
Conference
21st International Nondestructive Testing and Evaluation of Wood Symposium, 24-27 September, 2019, Freiburg, Baden-Württemberg, Germany
Available from: 2019-10-14 Created: 2019-10-14 Last updated: 2020-09-23Bibliographically approved
Sehlstedt-Persson, M., Hansson, L., Couceiro, J. & Vikberg, T. (2019). Konditionering av virke vid olika fuktkvoter: studier i tomograf. Skellefteå
Open this publication in new window or tab >>Konditionering av virke vid olika fuktkvoter: studier i tomograf
2019 (Swedish)Report (Other academic)
Abstract [sv]

Fuktförändringar i virke under pågående konditionering har aldrig tidigare studerats i tomograf.

Resultat av denna labbstudie av diffusionsbaserad, icke-kondenserande jämviktskonditionering vid olika fuktkvotsnivåer sammanfattas enligt följande: (Notera att torkningsspänningar inte utvärde­rats i denna studie utan enbart fuktförändringar.)

  • Studien styrker industriella erfarenheter att konditionering ”tar bättre” på virke nedtorkat till lägre fuktkvot jämfört än om fuktkvoterna är högre.
  • Försöken ger en god fingervisning om hur länge konditionering bör pågå för en viss önskad medel­fuktkvotshöjning i ett industriellt vanligt förekommande klimat 70 °C och psykrometer­skillnad 2° vilket motsvarar en jämviktsfuktkvot på 16,8%. Vill man ex höja medelfuktkvoten från 10 – 12% visar resultaten att 4 timmars konditionering är tillräckligt för furuvirket. Att i samma klimat höja medel­fuktkvoten 2% vid högre startfuktkvoter (mellan 14–23%) har inte i något fall varit möjligt för vare sig gran eller furu under de 8 timmar som konditionering pågick. Det är också viktigt att påpeka att konditioneringsklimatet i dessa labbförsök har uppnått börvärden mycket snabbt (figur 3) vilket inte är fallet vid stora virkeslaster i industriskala där basningskapacitet och blåsdjup påverkar tid till uppnådda börvärden.
  • Vad gäller fuktkvotsskillnad nära ytorna ses generellt en utplaning av fuktförändringar i samtliga försök efter 3–4 timmar.
  • Fuktkvotsnivån spelar roll för den inledande fuktkvotsförändringen inom tvärsnittet: ju torrare virke desto snabbare förändring.
  • När konditioneringen startar är fuktvandringen i splintved effektivare än i kärnved vilket sannolikt förklaras av splintvedens högre diffusivitet.
  • Vad gäller eventuella skillnad mellan träslag är det inte möjligt att dra några slutsatser.
  • Metodstudien visar att upplösningen i tomografen är tillräcklig för att kunna utvärdera fuktkvotsförändringar nära virkesytorna i ca 3 mm tjocka skal.
Place, publisher, year, edition, pages
Skellefteå: , 2019. p. 28
Series
TräCentrumNorr
Keywords
trä, furu, gran, tomografi, torkning, konditionering
National Category
Engineering and Technology Other Mechanical Engineering
Research subject
Wood Science and Engineering
Identifiers
urn:nbn:se:ltu:diva-72978 (URN)
Projects
”TiiN, TräInnovation i Norr”
Funder
Swedish Agency for Economic and Regional Growth
Note

Denna studie har utförts i projektet "Utveckling av industriell virkestorkning" inom ramen för projektet ”TiiN, TräInnovation i Norr”  

Available from: 2019-02-21 Created: 2019-02-21 Last updated: 2023-09-05Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5869-2236

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