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- Sandberg, Dick, 1967-
(författare)
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Simuleringsverktyg för skiktlimning – nulägesanalys av processen och prioriterade arbetsområden. : Simulation Tools for laminated bending of veneer - state of the art for the process and priority work.
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport är en dokumentation av villkor och förutsättningar som gäller vid skiktlimning av faner för inredning och möbler inom delprojektet ”Skiktlimning av björk och bok” vid AB Åberg & Söner i Lönsboda.En analys av skiktlimningsprocessens status ger vid handen:Stora kunskapsluckor finns om de grundläggande fenomenen vid skiktlimning.Tydlig förändring av processerna sker mot:- mer avancerade produkter- korta serier- korta leveranstider- fokusering på pris och kvalitetSkiktlimning är ett av de få områden där svensk trämanufakturindustri har möjlighet att konkurrera mot låglöneländer.Ett framtidsscenario är att om 5 till 10 år kommer i stort sett alla beställningar via arkitekter och designers till företaget på elektronisk väg. Ritningarna är gjorda med hjälp av något CAD program. På grund av kravet på korta ledtider och utvecklingen mot allt mer avancerade produkter måste man kunna öppna och läsa olika CAD-program och utifrån dessa ritningar kunna avgöra om det är möjligt att i sin tillverkning tillverka den önskade produkten. Till sin hjälp i denna situation är företaget i behov av ett simuleringsverktyg i form av en matematisk modell som man har tillgång till. Med hjälp av detta verktyg skall risken kunna beräknas för att lokala brott i faneren inträffar, sprickor och limsläpp uppstår, samt att andra orsaker vid produktionen förorsakar kassaktioner av den färdiga eller nära färdiga produkten. Ytterligare ett önskemål är att det ritningsunderlag som man i digital form får från arkitekter i dess ursprungsform kan ligga till grund för tillverkningen. En analys av dagens tillverkning i relation till de framtida behoven som företaget kommer har genomförts och redovisas med förslag.
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| 4. |
- Gräns, Daniel, et al.
(författare)
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Genetic variation and relationships to growth traits for microfibril angle, wood density and modulus of elasticity in a Picea abies clonal trial in southern Sweden
- 2009
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 24:6, s. 494-503
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Tidskriftsartikel (refereegranskat)abstract
- Genetic variation in wood density, microfibril angle (MFA), wood stiffness (MOE), height, diameter and volume was investigated in a 26-year-old Norway spruce [(Picea abies (L.) Karst.] clonal trial in southern Sweden. Wood quality measurements were performed on 10 mm increment cores using SilviScan. For MFA, mean values of annual rings showed the highest value (30°) at ring 2 counting from the pith, followed by a steep decrease and a gradual stabilization around ring 12 at approximately 14°. MOE showed a monotonic increase from 5 GPa to 14 GPa when moving from pith to bark. High broad-sense heritability values were found for wood density (0.48), MFA (0.41) and MOE (0.50). All growth traits displayed heritability values of similar magnitudes as reported in earlier studies. The generally high age-age correlations between different sections of the wood cores suggested that early selection for wood quality traits would be successful. Owing to unfavorable genetic correlations between volume and MOE, the correlated response indicated that selection for volume only at age 10 would result in a 0.27% decrease in weighted MOE at age 26 for every 1% increase in volume.
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| 5. |
- Selig, Bettina, 1982-, et al.
(författare)
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Segmentation of Highly Lignified Zones in Wood Fiber Cross-Sections
- 2009
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Ingår i: Proceedings of the 16th Scandinavian Conference on Image Analysis (SCIA). - Heidelberg : Springer Berlin. - 9783642022296 ; 5575, s. 369-378
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Konferensbidrag (refereegranskat)abstract
- Lignification of wood fibers has important consequences tothe paper production, but its exact effects are not well understood. Tocorrelate exact levels of lignin in wood fibers to their mechanical proper-ties, lignin autofluorescence is imaged in wood fiber cross-sections. Highlylignified areas can be detected and related to the area of the whole cellwall. Presently these measurements are performed manually, which is te-dious and expensive. In this paper a method is proposed to estimate thedegree of lignification automatically. A multi-stage snake-based segmen-tation is applied on each cell separately. To make a preliminary evaluationwe used an image which contained 17 complete cell cross-sections. Thisimage was segmented both automatically and manually by an expert.There was a highly significant correlation between the two methods, al-though a systematic difference indicates a disagreement in the definitionof the edges between the expert and the algorithm.
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| 6. |
- Wernersson, Erik, 1984-, et al.
(författare)
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Generating synthetic μCT images of wood fibre materials
- 2009
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Ingår i: Proc. 6th International Symposium on Image and Signal Processing and Analysis. - Piscataway, NJ : IEEE. - 9789531841351 ; , s. 365-370
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Konferensbidrag (refereegranskat)abstract
- X-ray Computerized Tomography at micrometer resolution (μCT) is an important tool for understanding the properties of wood fibre materials such as paper, carton and wood fibre composites. While many image analysis methods have been developed for μCT images in wood science, the evaluation of these methods if often not thorough enough because of the lack of a dataset with ground truth. This paper describes the generation of synthetic μCT volumes of wood fibre materials. Fibres with a high degree of morphological variations are modeled and densely packed into a volume of the material. Using a simulation of the μCT image acquisition process, realistic synthetic images are obtained. This simulation uses noise characterized from a set of μCT images. The synthetic images have a known ground truth, and can therefore be used when evaluating image analysis methods.
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| 7. |
- Wernersson, Erik, 1984-, et al.
(författare)
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Segmentation of Wood Fibres in 3D CT Images Using Graph Cuts
- 2009
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Ingår i: Image Analysis and Processing – ICIAP 2009. - Berlin : Springer-Verlag. - 9783642041457 ; 5716, s. 92-102
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Konferensbidrag (refereegranskat)abstract
- To completely segment all individual wood fibres in volume images of fibrous materials presents a challenging problem but is important in understanding the micro mechanical properties of composite materials. This paper presents a filter that identifies and closes pores in wood fibre walls, simplifying the shape of the fibres. After this filter, a novel segmentation method based on graph cuts identifies individual fibres. The methods are validated on a realistic synthetic fibre data set and then applied on μCT images of wood fibre composites.
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| 10. |
- Adamopoulos, Stergios, et al.
(författare)
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Dimensional changes of extracted and non-extracted small wood specimens of black locust (Robinia pseudoacacia L.)
- 2003
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Ingår i: European Journal of Wood and Wood Products. - : Springer. - 0018-3768 .- 1436-736X. ; 61:4, s. 264-268
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Tidskriftsartikel (refereegranskat)abstract
- From straight grained heartwood of black locust (Robinia pseudoacacia L.), specimens, 3 cm×3 cm in cross section and 0.5 mm (or 10 mm) in axial direction, were cut and used for the determination of dimensional changes and the rate of tangential swelling. Mean radial, tangential and axial shrinkage was 5.30%, 6.67% and 0.16%, respectively, while the coefficient of anisotropy was 1.26. Half of the specimens for the determination of the rate of tangential swelling were extracted for 48 h with distilled hot water. The tangential dimensional change and the time taken to attain half maximum swelling in air-dry and oven-dry specimens were assessed according to a common technique. Extractive removal resulted in an increase of the total magnitude of tangential swelling in both air-dry and oven-dry specimens. However, no significant differences in time taken to attain half maximum swelling between air-dry and oven-dry specimens were observed after extraction. The rate of tangential swelling was lower in air-dry specimens than in oven-dry specimens after 30 min of immersion in water when were non-extracted and after 5 min of immersion in water when were extracted. Extracted air-dry specimens had a greater rate of tangential swelling than non-extracted air-dry specimens and the same occurred for oven-dry specimens. Extraction resulted in a higher diffusion coefficient for air-dry specimens. The diffusion coefficient calculated for non-extracted air-dry specimens (0.901×10−4 cm2/min) showed that black locust is a difficult species to impregnate.
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