| 1. |
- Van den Bulcke, Jan, et al.
(author)
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3D tree-ring analysis using helical X-ray tomography
- 2014
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In: Dendrochronologia. - : Elsevier BV. - 1125-7865 .- 1612-0051. ; 32:1, s. 39-46
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Journal article (peer-reviewed)abstract
- The current state-of-the-art of tree-ring analysis and densitometry is still mainly limited to two dimensions and mostly requires proper treatment of the surface of the samples. In this paper we elaborate on the potential of helical X-ray computed tomography for 3D tree-ring analysis. Microdensitometrical profiles are obtained by processing of the reconstructed volumes. Correction of the structure direction, taking into account the angle of growth rings and grain, results in very accurate microdensity and precise ring width measurements. Both a manual as well as an automated methodology is proposed here, of which the MATLAB (c) code is available. Examples are given for pine (Pinus sylvestris L), oak (Quercus robur L) and teak (Tectona grandis L.). In all, the methodologies applied here on the 3D volumes are useful for growth related studies, enabling a fast and non-destructive analysis.
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| 2. |
- Humar, Miha, et al.
(author)
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Introduction of the COST FP 1303 Cooperative Performance Test
- 2015
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In: Proceedings of the 46th IRG Annual Meeting.
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Conference paper (peer-reviewed)abstract
- COST Action FP 1303 “Performance of bio-based building materials” successfully started in October 2013 and an ambitious program was set up for the four year programme. COST Actions provide an excellent opportunity for collaborative research, e.g. in the frame of Round Robin tests.The idea of this respective test was to distribute a fairly simple test set up to as many places in Europe as possible in order to collect performance data reflecting the range of climatic exposure conditions. Furthermore we wanted to consider performance in its manifold meaning, i.e. optical, aesthetical, moisture and functional performance and durability. In contrast to traditional Round Robin tests aiming on comparative evaluation and validation of results from different test laboratories, this initiative aims on collecting performance data under climatically different exposure conditions. Therefore it was required to provide weather data from the respective test sites to allow establishing relationships between climate conditions and the following measured, which shall be evaluated regularly: decay, discolouration, development of mould and other staining fungi, corrosion, formation of cracks and moisture performance (if data logging device is included). Further details about the test and the first outcomes are presented in this paper.
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| 3. |
- Sedighi Moghaddam, Maziar, et al.
(author)
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Microstructure of chemically modified wood using X-ray computed tomography in relation to wetting properties
- 2017
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In: Holzforschung. - : Walter de Gruyter. - 0018-3830 .- 1437-434X. ; 71:2, s. 119-128
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Journal article (peer-reviewed)abstract
- X-ray computed tomography (XCT) was utilized to visualize and quantify the 2D and 3D microstructure of acetylated southern yellow pine (pine) and maple, as well as furfurylated pine samples. The total porosity and the porosity of different cell types, as well as cell wall thickness and maximum opening of tracheid lumens were evaluated. The wetting properties (swelling and capillary uptake) were related to these microstructural characteristics. The data show significant changes in the wood structure for furfurylated pine sapwood samples, including a change in tracheid shape and filling of tracheids by furan polymer. In contrast, no such changes were noted for the acetylated pine samples at the high resolution of 0.8
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| 4. |
- Sedighi Moghaddam, Maziar, 1981-, et al.
(author)
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Microstructure of chemically modified wood using X-ray computedtomography scanning in relation to wetting properties
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Other publication (other academic/artistic)abstract
- X-ray computed tomography was utilized to visualize and quantify the 2D and 3D microstructure of acetylated and furfurylated southern yellow pine (SYP) and maple samples. The total porosity and the porosity of different anatomical components, the cell wall thickness and the maximum opening of tracheid lumens were evaluated. The wetting properties (swelling and capillary uptake) were related to these microstructural characteristics. Our data show significant changes in the wood structure for furfurylated sapwood samples, including a change in tracheid shape and filling of tracheids by furan polymer. In contrast, no such changes were noted for acetylated samples at the resolution of the measurement (0.8 μm). The images obtained for furfurylated maple samples demonstrated that all ray cells and some vessel elements were filled with furan polymer while the fibres largely remained unchanged. Furfurylation significantly decreased the porosity of the sample, and this was observed in both earlywood and latewood regions in southern yellow pine softwood samples. In contrast, the total porosity of this softwood sample was hardly affected by acetylation. These findings are in line with wetting results demonstrating that furfurylation reduces both swelling and capillary uptake in contrast to acetylation which reduces mostly swelling. Cell wall thickness measurements revealed a significant increase after chemical modification especially at higher levels of furfurylation.
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| 5. |
- Wernersson, Erik L. G., et al.
(author)
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Postprocessing method for reducing phase effects in reconstructed microcomputed-tomography data
- 2013
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In: Optical Society of America. Journal A. - 1084-7529 .- 1520-8532. ; 30:3, s. 455-461
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Journal article (peer-reviewed)abstract
- With increased resolution in x-ray computed tomography, refraction adds increasingly to the attenuation signal. Though potentially beneficial, the artifacts caused by refraction often need to be removed from the image. In this paper, we propose a postprocessing method, based on deconvolution, that is able to remove these artifacts after conventional reconstruction. This method poses two advantages over existing projection-based (preprocessing) phase-retrieval or phase-removal algorithms. First, evaluation of the parameters can be done very quickly, improving the overall speed of the method. Second, postprocessing methods can be applied when projection data is not available, which occurs in several commercial systems with closed software or when projection data has been deleted. It is shown that the proposed method performs comparably to state-of-the-art methods in terms of image quality.
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| 6. |
- Saunders, Gary, et al.
(author)
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Leveraging European infrastructures to access 1 million human genomes by 2022
- 2019
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In: Nature reviews genetics. - : Springer Nature. - 1471-0056 .- 1471-0064. ; 20:11, s. 693-701
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Journal article (peer-reviewed)abstract
- Human genomics is undergoing a step change from being a predominantly research-driven activity to one driven through health care as many countries in Europe now have nascent precision medicine programmes. To maximize the value of the genomic data generated, these data will need to be shared between institutions and across countries. In recognition of this challenge, 21 European countries recently signed a declaration to transnationally share data on at least 1 million human genomes by 2022. In this Roadmap, we identify the challenges of data sharing across borders and demonstrate that European research infrastructures are well-positioned to support the rapid implementation of widespread genomic data access.
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| 7. |
- Yin, Haiyan
(author)
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Surface modification of birch and acetylated birch wood by silicone nanofilaments
- 2023
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Doctoral thesis (other academic/artistic)abstract
- The increasing awareness of sustainability motivates the development of building materials from renewable resources. The requirements of wood-based products with improved durability, for example, enhanced liquid repellence and UV and biological resistance, are still a challenge. Surface modification of wood by a superhydrophobic layer is one approach for counteracting the challenge. In this thesis, wood veneers of untreated and acetylated birch were surface-modified with fluorinated or non-fluorinated silicone nanofilaments in gas phase. Results demonstrated that the fluorine surface-modified birch (F-SMB) samples showed superamphiphobicity, i.e. a surface that repelled water, ethylene glycol and hexadecane with contact angles (CAs) greater than 150° and roll-off angles (ROAs) of less than 10°. Fluorine-free surface-modified birch and acetylated birch (SMB and SMAB) showed superhydrophobicity with static CA greater than 160° towards water and low ROA even for samples prepared with the shortest reaction time of 1 h.The surface-modified wood showed good wetting resistance analyzed by the multicycle Wilhelmy plate method. The SMB showed a lower water uptake than the acetylated wood while the SMAB showed the lowest water uptake, i.e. a pronounced increased water resistance, due to a combined effect of acetylation and surface modification. The silicone nanofilaments were not degraded after UV irradiation. Both the UV-irradiated SMB and SMAB still showed good wetting resistance with high static CAs and low water uptake. The UV-irradiated SMAB showed the lowest water uptake. The SMB and F-SMB showed good mold resistance with mold appearing later or with less intensity than those on the untreated birch due to the improved water resistance. All acetylated birch showed an even better mold resistance since the acetylation reduces the moisture absorption in the wood substance; whereas the surface modifications on acetylated birch played a slightly negative effect due to side effects from the surface modifications. All birch samples showed high blue stain coverage but almost no blue stain fungi were observed on the acetylated birch. The preconditioned and UV-irradiated acetylated wood samples showed good mold resistance as well. However, more outdoor tests need to be performed to further understand the resistance to mold and blue stain fungal growth on acetylated wood.The surface modifications of both untreated and acetylated birch give excellent water repellence and resistance, which shows the potential of such surface-modified wood in outdoor applications.
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