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Articoli di riviste sul tema "Wood structure"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 10 febbraio 2022

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1

Storodubtseva, Tamara. "Wood composite - improving its monolithic structure". Актуальные направления научных исследований XXI века: теория и практика 2, n. 3 (15 ottobre 2014): 253–56. http://dx.doi.org/10.12737/3967.

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2

Vincent, Julian FV. "Structure of wood". Current Opinion in Solid State and Materials Science 3, n. 3 (giugno 1998): 228–31. http://dx.doi.org/10.1016/s1359-0286(98)80095-8.

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3

Obata, Yoshihiro, Kazutoshi Takeuchi, Kouichi Akaeda e Kozo Kanayama. "Control of Grading Structure and Thermal Conductivity of Wood by Compressing Process". Materials Science Forum 492-493 (agosto 2005): 281–86. http://dx.doi.org/10.4028/www.scientific.net/msf.492-493.281.

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Compressed wood has different grading structure in an annual ring from one of natural wood. This paper treats the relationship between grading structures and effective thermal conductivity of natural and compressed woods. The Lorentz function and the power function are assumed as grading patterns of thermal conductivity. The grading thermal conductivity shows smaller effective thermal conductivity than the homogeneous wood with same average density. The sharper grading pattern gives much smaller effective thermal conductivity. The grading pattern of compressed wood is assumed as a model with locally compressed region. The calculated effective thermal conductivity by the model agrees with the measured thermal conductivity.

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4

Nowak, Jakub, Marek Florek, Wojciech Kwiatek, Janusz Lekki, Pierre Chevallier, Emil Zięba, Narcis Mestres, E. M. Dutkiewicz e Andrzej Kuczumow. "Composite structure of wood cells in petrified wood". Materials Science and Engineering: C 25, n. 2 (aprile 2005): 119–30. http://dx.doi.org/10.1016/j.msec.2005.01.018.

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5

Shen, Xiaoshuang, Pan Jiang, Dengkang Guo, Gaiyun Li, Fuxiang Chu e Sheng Yang. "Effect of Furfurylation on Hierarchical Porous Structure of Poplar Wood". Polymers 13, n. 1 (23 dicembre 2020): 32. http://dx.doi.org/10.3390/polym13010032.

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Some wood properties (such as permeability and acoustic properties) are closely related to its hierarchical porous structure, which is responsible for its potential applications. In this study, the effect of wood impregnation with furfuryl alcohol on its hierarchical porous structure was investigated by microscopy, mercury intrusion porosimetry and nuclear magnetic resonance cryoporometry. Results indicated decreasing lumina diameters and increasing cell wall thickness of various cells after modification. These alterations became serious with enhancing weight percent gain (WPG). Some perforations and pits were also occluded. Compared with those of untreated wood, the porosity and pore volume of two furfurylated woods decreased at most of the pore diameters, which became more remarkable with raising WPG. The majority of pore sizes (diameters of 1000~100,000 nm and 10~80 nm) of macrospores and micro-mesopores of two furfurylated woods were the same as those of untreated wood. This work could offer thorough knowledge of the hierarchical porous structure of impregnatedly modified wood and pore-related properties, thereby providing guidance for subsequent wood processing and value-added applications.

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Ota, Toshitaka, Takahiro Eitsuka, Haruki Yoshida e Nobuyasu Adachi. "Porous Apatite Ceramics Derived from Woods". Advanced Materials Research 11-12 (febbraio 2006): 247–50. http://dx.doi.org/10.4028/www.scientific.net/amr.11-12.247.

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Porous calcium phosphate ceramics (apatite and TCP) with wood-like microstructures, analogous to that of silicified wood, were prepared from natural woods as templates. The production of these ceramic woods was performed by the following process: (1) infiltration with an ethanol solution containing tri-ethyl phosphate and calcium nitrate tetra-hydrate into wood specimens, (2) drying to form a calcium phosphate gel in the cell structure, (3) firing in air to form apatite and TCP. The microstructure of the obtained ceramic woods retained the same structure as that of the raw woods: with the pore sizes corresponding to those of the original wood, and the major pores being unidirectionally connected.

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7

Xu, Hui Lan, e Woo-Yang Chung. "Estimation of the Chestnut Mass Transfer Coefficient through its Microscopic Structure - Chestnut Mass Transfer Coefficient through its Microscopic Structure -". Journal of the Korean Wood Science and Technology 40, n. 5 (25 settembre 2012): 352–62. http://dx.doi.org/10.5658/wood.2012.40.5.352.

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8

Garvey, Christopher J., Robert B. Knott, Matthew Searson e Jann P. Conroy. "USANS study of wood structure". Physica B: Condensed Matter 385-386 (novembre 2006): 877–79. http://dx.doi.org/10.1016/j.physb.2006.05.132.

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9

Nilsson, Thomas, e Roger Rowell. "Historical wood – structure and properties". Journal of Cultural Heritage 13, n. 3 (settembre 2012): S5—S9. http://dx.doi.org/10.1016/j.culher.2012.03.016.

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10

Wodzicki, T. J. "Natural factors affecting wood structure". Wood Science and Technology 35, n. 1-2 (19 aprile 2001): 5–26. http://dx.doi.org/10.1007/s002260100085.

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11

Min, Hee-Jeong, Tae-Seong Lee e Young-Soo Bae. "Structure Determination of Sucrose by Acetylation and Acid Hydrolysis". Journal of the Korean Wood Science and Technology 42, n. 2 (25 marzo 2014): 183–92. http://dx.doi.org/10.5658/wood.2014.42.2.183.

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12

Garrido, Pablo, Lars Edenius, Grzegorz Mikusiński, Anna Skarin, Anna Jansson e Carl-Gustaf Thulin. "Experimental rewilding may restore abandoned wood-pastures if policy allows". Ambio 50, n. 1 (9 marzo 2020): 101–12. http://dx.doi.org/10.1007/s13280-020-01320-0.

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AbstractLarge herbivores play key roles in terrestrial ecosystems. Continuous defaunation processes have produced cascade effects on plant community composition, vegetation structure, and even climate. Wood-pastures were created by traditional management practices that have maintained open structures and biodiversity for millennia. In Europe, despite the broad recognition of their biological importance, such landscapes are declining due to land-use changes. This calls for finding urgent solutions for wood-pasture conservation. To test whether introducing an ecological replacement of an extinct wild horse could have positive effects on wood-pasture restoration, we designed a 3-year rewilding experiment. Horses created a more open wood-pasture structure by browsing on seedlings and saplings, affected tree composition via selective browsing and controlled the colonization of woody vegetation in grassland-dominated areas. Thus, rewilding could be a potential avenue for wood-pasture restoration and biodiversity conservation. However, such benefits may not materialize without a necessary paradigm and political shift.

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13

Lyon, Jarod P., Simon J. Nicol, Jason A. Lieschke e David S. L. Ramsey. "Does wood type influence the colonisation of this habitat by macroinvertebrates in large lowland rivers?" Marine and Freshwater Research 60, n. 5 (2009): 384. http://dx.doi.org/10.1071/mf07233.

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Submerged woody habitat provides the major structure around which ecological processes operate in many lowland rivers. Colonisation by macroinvertebrates was measured in a south-eastern Australian river over a 32-day period in an experiment testing the hypothesis that wood type influences the invertebrate assemblage structure. The wood types were green wood, dry wood, and dry but previously waterlogged wood. All wood used was river red gum (Eucalyptus camaldulensis). Macroinvertebrates colonised previously waterlogged wood more rapidly than green or dry wood. The assemblage structure varied significantly over the sampling period, with copepods and cladocerans numerically dominating the assemblage during the first few days after the introduction of the wood. The assemblage became more diverse through time and was numerically dominated by dipterans, ephemeropterans and trichopterans. The results indicate that there was little difference in the time taken for macroinvertebrate colonisation after wood introduction when using either green or dry wood. This has implications for large-scale restoration projects, where green wood is likely to be a more readily available option for reintroduction than dry wood.

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14

Liu, Rushan, e Deyuan Tian. "Study on Analogy Calculation Method for Seismic Vulnerability of Earth-Wood Structure Houses". Mathematical Problems in Engineering 2020 (27 luglio 2020): 1–10. http://dx.doi.org/10.1155/2020/3525896.

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Earth-wood structure houses often cause large casualties and economic losses in historical earthquakes. Therefore, it is estimated that the seismic vulnerability of civil structures in areas that have not experienced earthquakes is of great significance for earthquake prevention and disaster reduction. In this paper, an analogy calculation method was proposed for calculating the seismic vulnerability of earth-wood structure houses in unknown regions from the seismic vulnerability of earth-wood structure houses in known regions. Firstly, the main factors affecting the seismic capacity of earth-wood structure houses were determined, and the weights of influence of influencing factors on the overall seismic capacities of buildings under different seismic intensities were determined by using the fuzzy analytical hierarchy approach; secondly, the relative seismic capacities of the main influencing factors are analogically scored by considering the differences in influencing factors in different regions. Finally, based on the vulnerability matrix of earth-wood structure houses in existing regions and comprehensive evaluation of relative seismic capacities of earth-wood structures, the vulnerability matrix of unknown earth-wood structures was calculated by analogy. The results of trial calculation showed that this method has higher reliability and effectiveness. At the end of the article, the vulnerability analysis of earth-wood structure houses in Shigatse, Tibet, was carried out using this method, and the vulnerability curve was initially given.

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15

Misztal, Barbara, e Anna Mielińska. "SELECTION CRITERIA OF THERMO-INSULATING MATERIALS TO INSULATE WOODEN BUILDING FACILITIES". Space&FORM 2020, n. 46 (24 giugno 2021): 87–100. http://dx.doi.org/10.21005/pif.2021.46.b-05.

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The article presents the structure of wood as a fibrous composite made up of cells susceptible to moisture absorption. Attention was paid to the impact of insulation materials on the durability of wood. The flow of moisture in materials such as wood and glass wool representing a group of porous and non-absorbing materials is shown. Microscopic pictures of pine and oak wood, wood fibre mats and glass wool are shown. The full construction of fibers of glass wool and other e. g. mineral wool, makes them extremely non-beneficial for warming partitions in buildings involving wood. Materials with a stable heat conductivity in terms of natural humidity changes in construction works were recommended.

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16

Balakshin, Mikhail Yu, Ewellyn A. Capanema, Barry Goldfarb, John Frampton e John F. Kadla. "NMR studies on Fraser fir Abies fraseri (Pursh) Poir. lignins". Holzforschung 59, n. 5 (1 settembre 2005): 488–96. http://dx.doi.org/10.1515/hf.2005.081.

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Abstract The composition of mature, juvenile uninfested and juvenile infested Fraser fir wood (Rotholz) and the structures of lignins isolated from these woods were elucidated to verify differences between juvenile and mature wood and the effect of balsam woolly adelgid (BWA) infestation. Milled wood lignin (MWL) isolated from mature, juvenile and Rotholz wood were comprehensively characterized using heteronuclear multiple quantum coherence (HMQC) and quantitative 13C NMR techniques. The Rotholz wood was found to have ∼13% higher lignin content and more than five-fold the amount of galactans than that of the uninfested wood. Rotholz lignin possesses higher amounts of p-hydroxyphenyl units and aliphatic OH groups and a lower amount of alkyl-O-alkyl linkages and dibenzodioxocin moieties. The degree of condensation of the Rotholz lignin was rather similar to that of normal wood. Only small differences in the structure of mature and juvenile wood components were found.

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17

Park, Se-Yeong, In-Gyu Choi e Young-Soo Bae. "Structure Determination of the Extractives from the Taxus Cuspidata Fruits". Journal of the Korean Wood Science and Technology 41, n. 6 (25 novembre 2013): 566–75. http://dx.doi.org/10.5658/wood.2013.41.6.566.

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18

Meng, Xin, Yong Feng Li, Jian Li e Yi Xing Liu. "Structure Characterization for Wood-PMMA Composite". Applied Mechanics and Materials 26-28 (giugno 2010): 971–75. http://dx.doi.org/10.4028/www.scientific.net/amm.26-28.971.

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A new composite, wood-polymer composite, was fabricated by formation of poly (methyl methacrylate) in wood cellular structure. Methyl methacrylate (MMA) monomer and a few of 2,2'- azobisisobutyronitrile (AIBN) as an initiator, as well as several drops of pyrimidine as catalyst were first impregnated into wood porous structure under a pressure condition, and then initiated for thermal polymerization through a catalyst-thermal treatment. The structure of Wood-PMMA Composite was characterized by SEM, FTIR, XRD, and its thermal stability was also examined. The results indicate that PMMA polymer generated in wood cellular structure as an amorphous form, and interacted with wood cell walls, resulting in chemical combination between them. The thermal stability of Wood-PMMA composite was higher than untreated wood under 450°C.

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19

Bian, Zhi Hui, Tie Cheng Wang, Shi Yong Zhao e Xu Guang Li. "A Study on Node Connection Technology of Wood Structure". Applied Mechanics and Materials 405-408 (settembre 2013): 3094–98. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.3094.

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As an important component of modern wood frame system, the design and construction of node are also constantly developing. By taking Sino-Canadian Exchange Center for Low-carbon & Building Energy-saving housing project for example, this paper is to introduce the node connection technology of the wooden structure in three aspects:new joint connection technology of Wood components , connection of Wood - concrete structures and node details processing in the wood structure, which plays a positive reference role in the development and promotion of modern wooden architecture node technology.

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20

Park, Joo-Saeng, e Kweon-Hwan Hwang. "Moment Resistance Performance of Each Joint for Post-Beam Frame Structure". Journal of the Korean Wood Science and Technology 39, n. 1 (25 gennaio 2011): 8–14. http://dx.doi.org/10.5658/wood.2011.39.1.8.

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21

Nowak, J., D. Nowak, P. Chevallier, J. Lekki, R. van Grieken e A. Kuczumow. "Analysis of Composite Structure and Primordial Wood Remains in Petrified Wood". Applied Spectroscopy 61, n. 8 (agosto 2007): 889–95. http://dx.doi.org/10.1366/000370207781540141.

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Among all the fossils, petrified wood belongs to the most impressive and most common of materials. Still, its study has not exceeded the purely phenomenological level. The recognition of the conserved structure of petrified wood seems to be of meaning for understanding the geological past, the complete carbon cycle inside the Earth, and the structure of potential new materials. The first ever published spatial distributions of the remains of the primordial organic material (lignin, cellulose, pectins) in the cells of permineralized wood, from Dunarobba (Central Italy), are presented here. They were collected using μ-Raman spectrometry. The composite nature of the petrified material (calcite located in the lumena of cells and goethite located in the cell walls) was confirmed by electron, proton, and X-ray microprobes. The structure of the cell walls was well preserved. The mineralization process was induced by the tracheidal water flow and was stopped after formation of pipe-like goethite shielding of the cell walls on the cellulose scaffolds. The chemical (Eh and pH ranges) and probable microbial conditions for such a pattern of mineralization were determined. We estimate that substantial amounts of the primordial organic matter were preserved in bodies of petrified wood on a global scale. The wood petrifaction process, if well understood, can be a basis for the production of “everlasting” organic–inorganic composite compounds.

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22

Zhang, Lu, Zehua Chen, Haoran Dong, Shuai Fu, Lan Ma e Xiaojun Yang. "Wood plastic composites based wood wall's structure and thermal insulation performance". Journal of Bioresources and Bioproducts 6, n. 1 (febbraio 2021): 65–74. http://dx.doi.org/10.1016/j.jobab.2021.01.005.

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23

Qin, Zhuo Kai, Jia Sheng Zhang, Yu Tian Yang, Jian Ju Luo e Wei Gao. "Constructing 3D Model of Hardwood Structure". Key Engineering Materials 719 (novembre 2016): 9–13. http://dx.doi.org/10.4028/www.scientific.net/kem.719.9.

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Model constructing was conducted with 3D Studio Max modeling technology for hardwood minute structure in three steps. In the first step, the single-cell models were built according to the true form and shape of various kinds of cells, including vessel elements, wood-fiber cells, longitudinal parenchyma cells and ray cells. In the second step, the single-tissue models for all the four kinds of wood tissues (vessel, wood-fiber, longitudinal parenchyma and wood ray) were constructed by setting the same kind of single-cell models together according to the cell grouping ways inside true wood. In the third step, according to the distributing and arranging ways of the four kinds of wood tissues inside true wood, the whole model of wood block in minute structure was constructed by assembling the four kind of single-tissue models in a block. After that, the virtual model in computer was materialized by means of modern 3D printing technology, and finally the solid model in minute structure of Ficus microcarpa wood was constructed.

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24

Bogolitsyn, Konstantin G., Ivan N. Zubov, Maria A. Gusakova, Dmitry G. Chukhchin e Anna A. Krasikova. "Juniper wood structure under the microscope". Planta 241, n. 5 (4 febbraio 2015): 1231–39. http://dx.doi.org/10.1007/s00425-015-2252-1.

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25

Lewis, Ann M. "A Video Technique for Imaging the Three-Dimensional Architecture of Wood". IAWA Journal 16, n. 1 (1995): 81–86. http://dx.doi.org/10.1163/22941932-90001392.

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This paper describes a video micrographic technique to image the internal three-dimensional structure of wood. The technique uses high resolution video and an optical disk recorder to give immediate access to noise-free serially-recorded images in both still-frame and motion modes. By using a hydrophilie embedding medium, small woody tissue samples can be successfully embedded, sectioned at thicknesses that are useful for video micrography of the exposed tissue surface, and serially recorded to analyse three-dimensional architecture. The technique can be used by researchers working in wood anatomy, xylem development, and water transport. It also promises to be useful for studying the three-dimensional architecture of small, non-woody structures. Modifications of the technique make it useful for larger woody and non-woody material.

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26

Kim, Young-Hee, Jung Eun Choi, Jin-Young Hong, Chang Wook Jo, Jeung-Min Lee e Soo Ji Kim. "A New Compound Isolation and Structure Analysis from Phellodendron Amurense Fruit Extract". Journal of the Korean Wood Science and Technology 41, n. 4 (25 luglio 2013): 269–75. http://dx.doi.org/10.5658/wood.2013.41.4.269.

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27

Pagliara, Simone, Deep Roy e Michele Palermo. "Scour Features at Wood Bundles". Water 13, n. 15 (31 luglio 2021): 2118. http://dx.doi.org/10.3390/w13152118.

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Structures like blunt-nosed chevrons, log deflectors and double-winged log frames help in modifying the flow regime in the channel by concentrating the flow and increasing navigability. Moreover, they create scour pools in the downstream stilling basin, which can be used either as fish refuge or as an in-stream storage site for previously dredged material. In this respect, the use of wood debris in the channel in the form of wood bundles has gained attention for the ability of these structures to integrate into the surrounding fluvial habitat and to divert the flow partially towards the central part of the channel when placed in curves. Considering the absence of studies dealing with wood bundles as a restoration structure, the aim of this paper is to analyse the scour mechanism and equilibrium scour morphology of wood bundles in straight and curved channels. In doing so, a wide range of hydraulic conditions, structure positions and configurations were tested. Thereafter, dimensional analysis was carried out to derive useful empirical relationships to predict the maximum scour depth and length as well as the maximum dune height based on a novel, equivalent Froude number, which accounts for the effects of channel curvature and structure position. Moreover, the various resulting scour morphology types were classified, and conditions of their existence were determined depending on the abovementioned Froude number and other key hydraulic parameters.

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Li, Yong Feng, Yi Xing Liu, Jiang Tao Shi e Gang Li. "Structure and Property of PGMA/Wood Composite". Advanced Materials Research 87-88 (dicembre 2009): 456–61. http://dx.doi.org/10.4028/www.scientific.net/amr.87-88.456.

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In order to prepare a wood-based composite material which, as a type of multifunctional and natural bio-based material, possesses satisfactory mechanical properties, excellent durability (i.e., decay resistance and dimensional stability), and Aenvironmental characteristic, the study presents a new method which is based on the cellular structure of wood by initiating polymerizable monomers for in situ polymerization. Glycidyl methacrylate (GMA) as a multifunctional and polymerizable monomer was chosen, and impregnated into the porous structure of wood. After a thermal-catalyst process, the wood-based composite, PGMA/Wood, was prepared. The structure of this material was analyzed by SEM, FTIR and XRD; and its performance was also determined. The analyzing results show that GMA not only polymerized in the cellular structure in a solid form and amorphous form, which fully and uniformly filled in wood cell lumen, but also sufficiently grafted onto wood cell walls in a chemical level, resulting in tight contact between wood cell walls and resultant polymers (PGMA) without any obvious cracks. The test results of mechanical properties show that the modulus of rupture (MOR), modulus of elasticity (MOE), compression strength, and hardness of PGMA/Wood increased by 82%, 122%, 139%, and 348% over those of untreated wood, respectively. The test results of durability show that the dimensional stability and decay resistance of PGMA/Wood improved 44% and 91% than those of untreated wood, respectively. Such composite could be widely applied in the fields of construction, furniture and traffic.

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Stachowiak-Wencek, Agata, Monika Bartkowiak, Magdalena Zborowska e Jan Bocianowski. "Effects of aqueous ammonia vapor on the color and chemical structure of Robinia pseudoacacia and oak woods". BioResources 15, n. 3 (10 giugno 2020): 5812–28. http://dx.doi.org/10.15376/biores.15.3.5812-5828.

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Aqueous ammonia vapors were found to affect the color and structure of oak (Quercus L.) and Robinia pseudoacacia L. woods. The modification process was performed using 5% or 10% ammonia concentration at a temperature of 120 °C, 130 °C, or 140 °C. Wood mass and volume change coefficients were determined. The degree of wood discoloration was determined using the Commission Internationale de l’Eclairage (CIE) Lab system, and the changes to the chemical structure were determined using the Fourier transform infrared (FTIR) technique. The samples darkened due to the modification. They also became less red and less yellow. It was found that Robinia wood was more discolored. The total color change (ΔE*) of Robinia wood ranged from 39.0 to 41.9, and of oak wood ranged from 26.8 to 33.3. The L* and b* color coordinates had a significant effect on the ΔE. Analysis of variance showed that in most cases both the concentration of the aqueous ammonia solution and the process temperature alone did not cause significant differences in the colour of the wood (GenStat 18ed (VSN International 2015)). However, the interaction between concentration and temperature was important. Analysis of wood structure via FTIR showed that during the applied treatment, wood underwent chemical changes and that the effects were different in the compared species.

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Reine, Barbara A., Norman J. Fowler e R. M. Fisher. "Quantitative Scanning Electron Microscopy of the Cellular Structure of Wood". Proceedings, annual meeting, Electron Microscopy Society of America 48, n. 1 (12 agosto 1990): 554–55. http://dx.doi.org/10.1017/s042482010018152x.

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Abstract (sommario):

The physical properties of wood, such as density, moisture content, tensile, compression and shear strength, elastic modulus and anisotropy all vary considerably between different species of wood. These variations are reflected in the long standing differentiations into hard and soft woods that have been established as well as quality classifications or commercial grades such as clear grain, select, structural etc. that are commonly used. These variations in properties arise from differences in the size, shape and distribution of the cells, as well as in the thickness of the cellulose-lignin walls that enclose them.Scanning electron micrographs that are representative of the variations in cellular structure that exist between woods are shown in Figure 1 for ultrasoft hard maple and ultrasoft cork oak. These higher magnification images illustrate the duplex cell configuration that is required to sustain the growth of trees and support their height. Although the differences in cell structure are quite apparent in the micrographs, any quantitative interpretation of the various properties mentioned above requires detailed measurements of specific microstructural components to obtain statistically significant measurements of the relevant structural components.

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Lee, Hyun-Mi, Dong-Heub Lee e Won-Joung Hwang. "Penetration of ACQ Treatment and its Effect of Degradation on Wood Tissues (Structure)". Journal of the Korean Wood Science and Technology 41, n. 6 (25 novembre 2013): 576–82. http://dx.doi.org/10.5658/wood.2013.41.6.576.

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32

Hirayama, Haruka, Takuya Akiyama, Satoshi Kimura, Deded S. Nawawi, Wasrin Syafii, Tomoya Yokoyama e Yuji Matsumoto. "Influence of the p-hydroxyphenyl/guaiacyl ratio on the biphenyl and β-5 contents in compression wood lignins". Holzforschung 73, n. 10 (27 agosto 2019): 923–35. http://dx.doi.org/10.1515/hf-2019-0012.

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Abstract Reaction woods of three softwoods, Pinus merkusii, Cryptomeria japonica and Cedrus deodara, were investigated by alkaline nitrobenzene oxidation (NBO) to characterize the condensed-type structures in compression wood lignins. A novel biphenyl-type NBO product carrying guaiacyl (G)- and p-hydroxyphenyl (H)-units, dehydrovanillin-p-hydroxybenzaldehyde (HG-biphenyl product), was identified using the authentic standard compound. On the basis of the yield of this novel NBO product, as well as those of GG-biphenyl-, β-5-, and uncondensed-type products [e.g. dehydrodivanillin, 5-formylvanillin, vanillin and p-hydroxybenzaldehyde], the compression wood lignins contained more HG-type biphenyl and H-type β-5 structures than the opposite wood lignins. The increase in the condensed-type structure content was largely offset by the decreases in the content of GG-biphenyl and G-type β-5 structures. Consequently, the relative yields of biphenyl, β-5 and uncondensed-type NBO products were very similar between the compression wood and the opposite wood, even though the H-unit having no methoxy group on its aromatic ring can be assumed to have a greater probability to form condensed-type structures during lignin biosynthesis than the G-unit.

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Rosner, Sabine. "Hydraulic and biomechanical optimization in norway spruce trunkwood – a review". IAWA Journal 34, n. 4 (2013): 365–90. http://dx.doi.org/10.1163/22941932-00000031.

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Abstract (sommario):

Secondary xylem (wood) fulfills many of the functions required for tree survival, such as transport of water and nutrients, storage of water and assimilates, and mechanical support. The evolutionary process has optimized tree structure to maximize survival of the species, but has not necessarily optimized the wood properties needed for lumber. Under the impact of global warming, knowledge about structure-function relationships in tree trunks will become more and more important in order to prognosticate survival prospects of a species, individuals or provenances. Increasing our knowledge on functional wood anatomy can also provide valuable input for the development of reliable, fast, and at best quasi-non-destructive (e.g. wood coring of mature trunks) indirect screening techniques for drought susceptibility of woody species. This review gives an interdisciplinary update of our present knowledge on hydraulic and biomechanical determinants of wood structure within and among trunks of Norway spruce (Picea abies (L.) Karst.), which is one of Europe’s economically most important forest tree species. It summarizes what we know so far on 1) withinring variability of hydraulic and mechanical properties, 2) structure-function relationships in mature wood, 3) mechanical and hydraulic demands and their tradeoffs along tree trunks, and 4) the quite complex wood structure of the young trunk associated with mechanical demands of a small tree. Due to its interdisciplinary nature this review is addressed to physiologists, foresters, tree breeders and wood technologists.

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34

Dong, Xiao Ying, Ding Wang Gong, Zhen Bo Liu e Yi Xing Liu. "Wood-Polymer Composite Fabricated by Polymerization of Monomers within Wood Porous Structure". Advanced Materials Research 549 (luglio 2012): 699–702. http://dx.doi.org/10.4028/www.scientific.net/amr.549.699.

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A novel composite, wood-polymer composite, was fabricated by polymerization of functional monomers within wood porous structure. The wood was a fast-growing plant wood, Micheliamacclurel wood, which was rarely reported in previous studies, and two functional monomers, glycidyl methacrylate and ethylene glycol dimethacrylate, were novelly employed. The monomers, added with a few Azo-bis-isobutryonitrile as initiator, and maleic anhydride as catalyst, were first impregnated into wood pores under vacuum/pressure conditions, and then in-situ polymerized into polymers through a catalyst-thermal treatment. After the processes, wood-polymer composite was resulted. SEM and FTIR analysis for the composite indicated that the monomers polymerized into solid polymer, which fully filled up wood pores, and the resulted polymer grafted onto wood matrix, resulting in good interface combination between polymer and wood matrix. Such composite with satisfactory interface can be potentially applied as structural material in construction field.

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35

Fink, Siegfried. "Transparent Wood – A New Approach in the Functional Study of Wood Structure". Holzforschung 46, n. 5 (gennaio 1992): 403–8. http://dx.doi.org/10.1515/hfsg.1992.46.5.403.

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36

Gryc, V., H. Vavrčík, M. Rybníček e E. Přemyslovská. "The relation between the microscopic structure and the wood density of European beech (Fagus sylvatica L.)". Journal of Forest Science 54, No. 4 (29 aprile 2008): 170–75. http://dx.doi.org/10.17221/1/2008-jfs.

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The aim of this study was to compare the structure of beech juvenile and mature wood in relation to wood density. The comparative analysis between juvenile and mature wood examined the diameter of vessels, the width and height of pith rays, and the number of vessels and pith rays per 1 mm<sup>2</sup>. The results show that the average vessel diameter as well as the width and height of pith rays reach statistically lower values in juvenile wood than in mature wood. On the other hand, no significant difference between the two types of wood has been found in terms of the frequency of vessels per 1 mm<sup>2</sup>. Having said that, the difference in the frequency of rays per 1 mm<sup>2</sup> between juvenile and mature wood is far from being negligible; juvenile wood has three times as many pith rays as mature wood. The density of juvenile wood is higher (ρ<sub>12</sub> = 726.07 kg/m<sup>3)</sup> than the density of mature wood ((ρ<sub>12</sub> = 701.50 kg/m<sup>3</sup>).

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37

Kim, Seok Ju, Kyung-Tae Lee, Won-Jae Youe, Sung-Suk Lee e Yong Sik Kim. "Structure Analysis of Water-soluble Polysaccharides Extracted from The Unripe Fruit of Cudrania tricuspidata". Journal of the Korean Wood Science and Technology 42, n. 6 (25 novembre 2014): 740–46. http://dx.doi.org/10.5658/wood.2014.42.6.740.

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38

Luo, Shi Bao. "Reinforcement Maintenance Method about Chinese Ancient Architectural Structure". Advanced Materials Research 250-253 (maggio 2011): 2206–10. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.2206.

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Abstract (sommario):

According to the ancient wooden architectural features, the different destructions of wood structures are discussed. On the basis of the importance and principle of Chinese historic building reinforcement and maintenance, ancient architectural wood structure reinforcement is introduced. Finally several proposes about the Chinese historic building reinforcement maintenance is given.

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39

Kononov, G. N., A. N. Verevkin, Yu V. Serdyukova e V. D. Zaitsev. "Mycolysis of wood, its products and their use. II. Biological and morphological processes of mycological destruction of wood". FORESTRY BULLETIN 24, n. 5 (ottobre 2020): 89–96. http://dx.doi.org/10.18698/2542-1468-2020-5-89-96.

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The article is devoted to some questions of the biology of wood-destroying fungi: the processes of their nutrition, growth, reproduction and development as xylophytes. The classification of «rot» formed by the action of wood-destroying fungi at the place of their location in a woody plant and the nature of the destruction of wood is considered. The characteristics of the stages of mycological destruction of wood in terms of changes in its morphology are given. The effect of changes in the structure of mycologically destroyed wood on its physical properties is shown.

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40

Gustafsson, Per Johan. "Modelling of mechanical properties of wood and wood-based materials". Schweizerische Zeitschrift fur Forstwesen 154, n. 12 (1 dicembre 2003): 504–9. http://dx.doi.org/10.3188/szf.2003.0504.

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Abstract (sommario):

Modelling is a wide concept. This paper describes various meanings of modelling in relation to mechanical properties of wood and wood-based materials. Three examples of modelling by means of the finite element method, presented in recent years in PhD theses, are used as reference points. They relate to modelling of the micro-structure of wood and its mechanical properties, modelling of drying-induced distortion of boards and modelling of the micro-structure and properties of dry-shaped cellulose fibre materials. The paper concludes with remarks on some studies relating to fracture simulations,strength modelling and glued joints.

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41

Metzler, B., e U. Hecht. "Three-dimensional structure of tubular air channels formed by Armillaria spp. in water-saturated logs of silver fir and Norway spruce". Canadian Journal of Botany 82, n. 9 (1 settembre 2004): 1338–45. http://dx.doi.org/10.1139/b04-092.

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Abstract (sommario):

Water saturation of wood impedes the availability of oxygen necessary for wood decay. Storage of logs under water sprinkling is therefore used as an economic method in forestry. However, sapwood decay caused by Armillaria spp. was found in logs under water sprinkling, even at a wood moisture content of more than 150% (dry weight basis). Decay was associated with the formation of tubular air channels discernible as bright streaks extending from the cambial region into the sapwood. Their light colour results from different refraction of light in gas-filled versus water-filled wood structures. To examine the structure of the tubular air spaces in greater detail, we sampled wood of Norway spruce (Picea abies (L.) Karst. and silver fir (Abies alba (Mill.)). Radial, transverse, as well as tangential sections of affected timber were examined, and a structural model of tubular air channels is presented. These structures are formed around wood rays by a tubular sheath of pseudoparenchymatous mycelium, which in its cellular structure is reminiscent of pseudosclerotial plates. This structure allows the efficiently located extrusion of water from water-saturated wood. The power necessary for this process is suggested to be the generation of gaseous CO2. Since the air channels are in contact with the external surface, they evidently act as a conduit allowing oxygen to enter and penetrate to a depth of several centimetres. By this unique arrangement of the tubular air channels, Armillaria spp. appear able to metabolize wood cells in an aerobic microenvironment within water-saturated wood. This results in wood decay leading to significant economic loss in stored timber despite the application of regular sprinkling.Key words: Armillaria spp., Picea abies, Abies alba, wood moisture content, oxygen supply, wood anatomy, wood decay.

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42

Kang, Chan-Young, Eung-Su Lee, Jae-Yun Ryu, Hyun-Jong Lee, Jun-Won Seo e Heon Park. "Chemical Structure of Ozonized Waste Cooking Oil and Wood Bonding Strengths of Reaction Products with pMD". Journal of the Korean Wood Science and Technology 38, n. 4 (25 luglio 2010): 316–22. http://dx.doi.org/10.5658/wood.2010.38.4.316.

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43

Akitomo, Mizuki, Rika Suzuki, Yutaka Ishimaru, Ikuho Iida e Yuzo Furuta. "Micropore Structure of Wood and Bamboo Charcoals". Mokuzai Gakkaishi 52, n. 4 (2006): 228–34. http://dx.doi.org/10.2488/jwrs.52.228.

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44

Micco, Veronica De. "Wood Structure in Plant Biology and Ecology". Open Forest Science Journal 6, n. 1 (2013): 36–37. http://dx.doi.org/10.2174/1874398601306010036.

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45

Walters, Stanley. "Wood, Sand and Stars: Structure and Theology". Toronto Journal of Theology 3, n. 2 (settembre 1987): 301–30. http://dx.doi.org/10.3138/tjt.3.2.301.

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46

Sjölund, J., A. Karakoç e J. Freund. "Accuracy of regular wood cell structure model". Mechanics of Materials 76 (settembre 2014): 35–44. http://dx.doi.org/10.1016/j.mechmat.2014.06.003.

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47

Baillères, Henri, Marielle Castan, Bernard Monties, Brigitte Pollet e Catherine Lapierre. "Lignin structure in Buxus sempervirens reaction wood". Phytochemistry 44, n. 1 (gennaio 1997): 35–39. http://dx.doi.org/10.1016/s0031-9422(96)00499-2.

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48

Goubel, C., M. Massenzio e S. Ronel. "Wood–steel structure for roadside safety barriers". International Journal of Crashworthiness 17, n. 1 (febbraio 2012): 63–73. http://dx.doi.org/10.1080/13588265.2011.625678.

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49

Novoselova, Irina. "Simulation of the structure of wood substrate". Актуальные направления научных исследований XXI века: теория и практика 2, n. 2 (11 marzo 2014): 62–65. http://dx.doi.org/10.12737/2968.

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50

Battipaglia, Giovanna, Veronica De Micco, Ute Sass-Klaassen e Paolo Charubini. "Wood structure in plant biology and ecology". Dendrochronologia 32, n. 3 (2014): 282–83. http://dx.doi.org/10.1016/j.dendro.2014.07.004.

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