Fungal decomposition of wood severely affects the soundness of timber constructions. The diagnosis of wood decay requires direct observations or sampling by skilled experts. Wood decay often occurs ...in obscure spaces, including the enclosed inner spaces of walls or under the floor. In this study, we examined the ability of machine olfaction to detect odors of fungi grown on common construction softwoods to provide a novel diagnostic method for wood construction soundness. The combination of a simple device equipped with semiconductor gas sensors (gas sensor array) and multivariate analysis discriminated a fungi-related odor from control odor without instrumental analysis (e.g., gas chromatography). This method is often referred to as machine olfaction or electronic nose. We measured the odor of wood test pieces that were infected with
Fomitopsis palustris
or
Trametes versicolor
and sound test pieces using a gas sensor array. The sensor responses of the specimens showed different patterns between the inoculated and control samples. Each specimen class formed independent groups in a principal component score plot, almost regardless of wood species, fungal species, or cultivation period. This method provides a new decay diagnosis method that is cost-effective and easy to operate.
This study assesses the changes in physical properties (particle size, shape, density) of Austrian pine (softwood) and European beech (hardwood), as they are mechanically processed from wood chips to ...pellets and then to milled pellets. A series of semi-industrial hammer mills and a semi-industrial pellet mill were used. The specific pelletizing and grinding energy, as well as the pellet mill and hammer mill capacity, were determined. Size, shape, and bulk density of the wood particles obtained at each processing step were studied. The pellet quality was analyzed according to international standards. Results show that the pelletization modifies the internal pellet particle shape and length due to the breakage of particles across their longest dimension, leading to more circular and less elongated particles. However, the particle width was nearly unaffected, indicating a directional fracture behavior for wood particles during pelletization. The particle breaking effect was more dominant for beech particles. Beech contained a lower amount of extractives than pine that led to higher specific pelletizing energy. In addition, beech pellets had a lower quality concerning durability and density. Relationships between specific grinding energies and characteristic product particle sizes were also determined. E.g., the specific energy for grinding pine pellets was about 10 kWh/t oven-dry wood for a characteristic product size of 0.8 mm, while grinding beech pellets required about 7 kWh/t oven-dry wood for a characteristic product size of 0.6 mm. The study concludes that less energy is needed to pelletize pine than beech under the same processing conditions, but more energy is needed to mill pine than beech.
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•Milling beech produces finer particles at lower milling energy input than pine.•Pelletization reduces the particle length and produces circular particles.•Milling pellets leads to further size reduction of internal pellet particles.•Pelletizing beech requires more energy than pine due to lack of extractives.
Spatial organization of signalling events of the phytohormone auxin is fundamental for maintaining a dynamic transition from plant stem cells to differentiated descendants. The cambium, the stem cell ...niche mediating wood formation, fundamentally depends on auxin signalling but its exact role and spatial organization is obscure. Here we show that, while auxin signalling levels increase in differentiating cambium descendants, a moderate level of signalling in cambial stem cells is essential for cambium activity. We identify the auxin-dependent transcription factor ARF5/MONOPTEROS to cell-autonomously restrict the number of stem cells by directly attenuating the activity of the stem cell-promoting WOX4 gene. In contrast, ARF3 and ARF4 function as cambium activators in a redundant fashion from outside of WOX4-expressing cells. Our results reveal an influence of auxin signalling on distinct cambium features by specific signalling components and allow the conceptual integration of plant stem cell systems with distinct anatomies.
Abstract Background Taxonomic identification of wood specimens provides vital information for a wide variety of academic (e.g. paleoecology, cultural heritage studies) and commercial (e.g. wood ...trade) purposes. It is generally accomplished through the observation of key anatomical features. Classic methodologies mostly require destructive sub-sampling, which is not always acceptable. X-ray computed micro-tomography (µCT) is a promising non-destructive alternative since it allows a detailed non-invasive visualization of the internal wood structure. There is, however, no standardized approach that determines the required resolution for proper wood identification using X-ray µCT. Here we compared X-ray µCT scans of 17 African wood species at four resolutions (1 µm, 3 µm, 8 µm and 15 µm). The species were selected from the Xylarium of the Royal Museum for Central Africa, Belgium, and represent a wide variety of wood-anatomical features. Results For each resolution, we determined which standardized anatomical features can be distinguished or measured, using the anatomical descriptions and microscopic photographs on the Inside Wood Online Database as a reference. We show that small-scale features (e.g. pits and fibres) can be best distinguished at high resolution (especially 1 µm voxel size). In contrast, large-scale features (e.g. vessel porosity or arrangement) can be best observed at low resolution due to a larger field of view. Intermediate resolutions are optimal (especially 3 µm voxel size), allowing recognition of most small- and large-scale features. While the potential for wood identification is thus highest at 3 µm, the scans at 1 µm and 8 µm were successful in more than half of the studied cases, and even the 15 µm resolution showed a high potential for 40% of the samples. Conclusions The results show the potential of X-ray µCT for non-destructive wood identification. Each of the four studied resolutions proved to contain information on the anatomical features and has the potential to lead to an identification. The dataset of 17 scanned species is made available online and serves as the first step towards a reference database of scanned wood species, facilitating and encouraging more systematic use of X-ray µCT for the identification of wood species.
The thermal treatment of wood is an alternative to the chemical treatment for preservation purposes. The heat treatment process improves wood's resistance to decay and its dimensional stability. ...However, mechanical strength decreases as a result of heat treatment. Therefore, the treatment parameters have to be optimized to keep this loss at a minimum while improving other properties. Thermal treatment is new in North America, and its parameters are not yet adjusted for the Canadian species. Carrying out the parameter adjustment in an industrial furnace requires many trials which are costly in terms of material and man-power. A laboratory study was carried out to determine the effect of different parameters of the heat treatment on the mechanical properties of birch in order to optimize this process. A thermogravimetric analyzer was built to carry out the laboratory tests. The impact of the process parameters-such as maximum treatment temperature, holding time at this temperature, heating rate, and gas humidity-on the mechanical properties of birch was investigated. Temperature distributions in wood and in gas as well as the weight loss of wood were measured during the experiments. Afterwards, hardness, modulus of elasticity, modulus of rupture, and resistance to screw withdrawal of the samples were measured. The relation between the process parameters and the resulting mechanical properties was examined.
Abstract
Nowadays, energy-saving building materials are important for reducing indoor energy consumption by enabling better thermal insulation, promoting effective sunlight harvesting and offering ...comfortable indoor lighting. Here, we demonstrate a novel scalable aesthetic transparent wood (called aesthetic wood hereafter) with combined aesthetic features (e.g. intact wood patterns), excellent optical properties (an average transmittance of ~ 80% and a haze of ~ 93%), good UV-blocking ability, and low thermal conductivity (0.24 W m
−1
K
−1
) based on a process of spatially selective delignification and epoxy infiltration. Moreover, the rapid fabrication process and mechanical robustness (a high longitudinal tensile strength of 91.95 MPa and toughness of 2.73 MJ m
−3
) of the aesthetic wood facilitate good scale-up capability (320 mm × 170 mm × 0.6 mm) while saving large amounts of time and energy. The aesthetic wood holds great potential in energy-efficient building applications, such as glass ceilings, rooftops, transparent decorations, and indoor panels.
Disposable consumer electronics become electronic waste at the end of their life, which can cause serious environmental pollution if discarded in the ground. Here, we have developed an all-wood-based ...flexible electronic device. The substrate is used to prepare self-densification wood-derived paper (SWP) at room temperature through the natural balsa wood (NW) self-densification process. Chemical treatment removed lignin and hemicellulose from NW, and the cell wall structure collapsed under the action of elastic capillary force generated by water evaporation. The hydrogen bonds between the cellulose fibers are further strengthened, and the arrangement of the cellulose fibers is maintained. The obtained SWP exhibits an excellent tensile strength of 229.4 ± 10.4 MPa in the fiber direction, which is 8.3–8.6 times (27.1 ± 1.7 MPa) and 4.2–4.8 times (51.2 ± 5.6 MPa) higher than NW and cellulose paper, respectively, and higher than some commercial plastics. In addition, it also exhibits excellent wetting performance and a certain degree of transparency. Finally, conductive wood carbon ink prepared from carbonized NW can be directly written on SWP using a Chinese brush to obtain customized patterns. We have demonstrated the application of an all-wood-based flexible electronic device in flexible sensors that can stably monitor finger movements. This newly developed all-wood-based composite can return to the carbon cycle of nature after its service life, providing a new way to replace traditional electronic products.
Ongoing urbanisation requires rapid, low-emission construction methods. Architects, investors and politicians are on the hunt for housing solutions that are fast and cost-effective, yet sustainable ...and flexible. Timber room modules meet all of these requirements: flexibility, variability, low construction and operating costs, short construction times thanks to high rates of prefabrication, a pleasant living environment, easy dismantling via detachable connections, excellent recyclability as well as a general acceptance by end users. This practical volume offers an overview, from the planning process to assembly, while contemporary examples show that building with room modules facilitates heretofore unimagined, multi-layered and differentiated architectures.
Xyloglucan: The Molecular Muscle of Trees Mellerowicz, Ewa J.; Immerzeel, Peter; Hayashi, Takahisa
Annals of botany,
11/2008, Letnik:
102, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Background Tension wood evolved in woody angiosperms to allow stems with secondary thickening to bend and thus maintain an optimal orientation. Stem bending is the result of longitudinal tensile ...stress that develops in tension wood tissues. In many species, a specialized secondary cell wall layer, the so-called gelatinous (G)-layer, develops, containing longitudinally orientated crystalline cellulose fibrils; these have been recently shown to generate the tensile stress by an unknown mechanism. The cellulose fibrils cannot, however, work in isolation. Both coherence between the fibrils and adherence of the G-layer to the adjacent cell wall layers are required to transfer the tensile stresses of the cellulose fibrils to the tissue. Previous work had not identified hemicelluloses within the G-layer. Recent Progress Sugar composition and polysaccharide linkage analyses of pure G-layers isolated by sonication have recently identified xyloglucan as the main non-cellulosic component of the G-layer. Xyloglucan has been detected by immunolabelling with the CCRC-M1 monoclonal antibody and by in-situ activity assays using XXXG–sulforhodamine substrate in the developing G-layers but not in the mature ones. However, xyloglucan endotransglucosylase/hydrolase (XTH) proteins persist in the G-layer for several years and the corresponding xyloglucan endotransglucosylase (XET) activity (EC 2·4·1·207) occurs in the adjacent layers. Correspondingly, several XTH-encoding transcripts were found to be up-regulated in developing tension wood compared with normal wood. Scope We propose that, during cellulose crystallization, a part of the xyloglucan is trapped inside the crystal, inducing longitudinal tensile stress within it; another part of it is accessible and present between the G-layer and the outer wall layers. XET activity that occurs persistently in the G-fibres maintains coherence between the G-layer and the adjacent secondary wall layers. It is postulated that these activities are essential for generation of tensile stress during fibre maturation in tension wood.
The Sarawak ‘Tar’ for Hadrah performance Sinin, Aaliyawani E.; Hamdan, Sinin; Said, Khairul A. Mohamad ...
Bioresources,
6/2024, Letnik:
19, Številka:
3
Journal Article
Recenzirano
Odprti dostop
This work was conducted using the PicoScope signal extraction procedure, which revealed remarkable insights regarding the belian wood and its application in Sarawak traditional ‘tar’ instrument. The ...‘tar’ is a small drum made of wood and attached with goat skin. A hadrah performance is done with the sound of the blow of the ‘tar’ and reciting poems praising Allah and the Prophet Muhammad by a group of players called the hadrah group. The ‘tar’ from belian wood had the highest pitch at 180 Hz i.e., F3# compared with the ‘tar’ from menggeris wood, which had the pitch D3# and A2 that also highlighted their importance in the Western scale. The overtones are not integer multiples of the fundamental frequency except for second and third overtones from ‘tar’ C (F2/F0 = 3 and F3/F0 = 4). Using Adobe Audition for Time Frequency Analysis (TFA) recordings for the ‘tar’, the data collection method provided insightful information. The communal efforts of practitioners, who are frequently grouped together, perpetuate the cultural heritage of hadrah. Essentially, by offering a thorough grasp of the intricate melodic details woven in hadrah’s cultural fabric, this research adds to the genre’s continuing heritage.
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