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1
Ruffinatto, Flavio, Gaetano Castro, Corrado Cremonini, Alan Crivellaro et Roberto Zanuttini. « A new atlas and macroscopic wood identification software package for Italian timber species ». IAWA Journal 41, no 4 (21 octobre 2019) : 393–411. http://dx.doi.org/10.1163/22941932-00002102.
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Abstract Wood identification has never been more important to serve the purpose of global forest protection, by controlling international illegal timber trade and enabling the enforcement of timber trade regulations. Macroscopic wood identification is the fastest method for the first identification of an unknown timber and, with proper training, it can be performed by operators in the timber industry, restorers and curators of cultural heritage, wood traders, designers, students and customs officers. Here we describe a wood atlas and accompanying software, SIR-Legno, developed for the identification of 48 Italian timber species based on a recently proposed list of macroscopic features for wood identification. For each species the atlas provides a complete macroscopic description plus information on natural durability, end-use class, physico-mechanical properties, conservation status, maximum diameter of the bole and most frequent uses. For each genus covered by the atlas, information about species number, CITES-listed species, main commercial timbers, similarly-named timbers from other genera, geographical distribution and notes on species or species group recognition at macroscopic and microscopic level are provided. SIR-Legno is an educational product, a handy identification key and a tool to search woods by their natural durability, end-use class and physico-mechanical properties. Both the atlas and the software can be freely downloaded from the web. Thanks to the adoption of a codified list of characters and a transferable design, SIR-Legno can be easily replicated or expanded to other databases in order to include new species. SIR-Legno is freeware and works on any version of Windows.
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Liu, Jiwei, Huifeng Yang, Yutao Zhou, Benkai Shi et Haotian Tao. « Parameter identification procedure for hysteretic shear-resistant properties of beech wood dowels ». BioResources 19, no 2 (22 avril 2024) : 3681–98. http://dx.doi.org/10.15376/biores.19.2.3681-3698.
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To evaluate the shear-resistant behavior of wooden dowels used in Blockhaus shear walls under cyclic load, 19 specimens under ten groups of conditions were prepared and tested. The failure modes, hysteresis curves, mechanical properties, stiffness degradations, and energy dissipation capacities of the specimens were studied. The test results showed that with the increase in the number of dowels, the initial stiffness and peak load of the specimens increased greatly. The diameter of the dowels had little influence on the mechanical properties of the specimens. Furthermore, the test findings demonstrated that the pretension load between the walls greatly enhanced the initial stiffness and energy dissipation capacity of specimens. A simplified finite element model was established in Opensees. Considering the effect of material variability, the parameters of single dowel shear spring and friction spring were identified by Genetic Algorithm with modified objective function in Matlab. The identified parameters were applied to the finite element model of the multi-dowel specimens. The simulation results were in good agreement with the test results, and the validity of the numerical model and parameter identification method was verified.
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Papandrea, Salvatore F., Maria F. Cataldo, Bruno Bernardi, Giuseppe Zimbalatti et Andrea R. Proto. « The Predictive Accuracy of Modulus of Elasticity (MOE) in the Wood of Standing Trees and Logs ». Forests 13, no 8 (11 août 2022) : 1273. http://dx.doi.org/10.3390/f13081273.
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The characterization of poplar wood assumes a strategic position to increase the competitiveness of the entire forest wood supply chain. From this aspect, the identification of wood quality represents a primary objective for researchers and private landowners. The quality of wood can be defined via traditional visual methods based on the experience of technicians or using traditional tools, such as incremental drills and sound hammers. The traditional properties of these traits, based only on visual characteristics, can outline a classification based on the macroscopic properties of wood with the aim of defining the volume of recoverable wood. However, this approach does not provide a good indicator of the physical or mechanical properties of wood. Mechanical tests of wood require the felling of trees with the correlated preparation of the specimens. A different solution to determine wood quality is based on the application of non-destructive technology (NDT). In this context, the aim of the present study was to determine the predictive accuracy of non-destructive analysis of the MOEd in standing trees and logs of a 22-year-old poplar clone and to examine the relationship with MOEs in sawn specimens. This relationship was also studied at three different stem heights. We non-destructively measured poplar trees and green logs using TreeSonic and Resonance Log Grader and compared the results with those obtained via a destructive method using a universal testing machine. The results showed that for clone I-214 poplar trees, the dynamic elastic moduli of standing trees and logs were validly correlated with the static elastic modulus. These results suggest that it is possible to evaluate the mechanical properties of poplar wood directly from standing trees using non-destructive techniques (NDT) and that this tool can be easily used to presort material in the forest.
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Hounlonon, Montcho Crépin, Adéyèmi Clément Kouchadé, Alexis Enagnon MEDEHOUENOU, Vincent GOHOUNGO, Aristide Comlan HOUNGAN et Basile Bruno KOUNOUHEWA. « Physical, Mechanical and Acoustic Characteristics of Anogeissus leiocarpus, Manilkara multinervis and Cylicodiscus gabunen-sis Woods Marketed in Benin in West Africa ». International Journal of Engineering & ; Technology 11, no 2 (24 novembre 2022) : 103–7. http://dx.doi.org/10.14419/ijet.v11i2.32049.
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Wood is a material used in construction, in instrument making, etc. In Benin, for heavy construction and construction on wetland, species with high technological characteristics are imported. But the performance of these imported species compared to local indigenous or exotic species remains to be verified. Thus, it is necessary to determine the basic technological properties of these species. It is within this framework that we have, on 500mm×20mm×20mm prismatic wood specimens of Anogeissus leiocarpus, Manilkara multinervis and Cylicodiscus gabunensis, used the acoustic method BING (Beam Identification by Non-destructive Grading) of CIRAD-Forest to determine the density Ï, the moduli of Young's modulus E, shear modulus G and the internal friction tan𛿠and then evaluated the modulus of specific stiffness E/Ï. On other 20 mm edge cubic specimens, we evaluated the reference physical properties of density, infradensity, total shrinkage, radial shrinkage, tangential shrinkage and shrinkage anisotropy. It appears that the wood of Anogeissus leiocarpus and Manilkara multinervis present better physico-mechanical characteristics than those of Cylicodiscus gabunensis. Anogeissus leiocarpus and Manilkara multinervis are very dense woods with physico-mechanical characteristics better than those of most Benin's popular species. The average modulus of elasticity in bending of these two species is higher than 12000 MPa while that of Cylicodiscus gabunensis is 10713 MPa. In compression all these species have an average modulus of elasticity above 14100 MPa. Cylicodiscus gabunensis wood tested is light with a lower shrinkage anisotropy than the other two species studied and have excellent acoustic properties. Its average specific stiffness (14 GPa) is higher than that of the other two species studied (12 GPa). The good physical-mechanical and acoustic properties of these species show that they are good structural timbers with also good potential for instrument making and acoustic insulation.Keywords: BING; Construction; Infradensity; Modulus of elasticity; Shrinkage anisotropy; Timber.
5
Kojima, Yoichi, Naho Kato, Kazuaki Ota, Hikaru Kobori, Shigehiko Suzuki, Kenji Aoki et Hirokazu Ito. « Cellulose Nanofiber as Complete Natural Binder for Particleboard ». Forest Products Journal 68, no 3 (2018) : 203–10. http://dx.doi.org/10.13073/fpj-d-18-00034.
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Abstract The demand for wood-based materials as an alternative to plywood is increasing, and a synthetic adhesive is typically used for the fabrication of such materials. The identification of replacements for standard adhesives poses a major challenge. In this study, we investigated the mechanical properties of particleboard bonded by cellulose nanofiber (CNF) and compared the mechanical properties of particleboard bonded by CNF with those of particleboard bonded by adhesive. CNF was added together with wood particles during the fabrication process. The target CNF addition amounts were 0, 3, 5, 10, and 20 weight percent. The bending and internal bond strengths of the particleboard with CNF increased, and its water absorption decreased as CNF content increased. The comparison between the boards prepared with adhesives and those with CNF showed that the properties of boards prepared with 20 weight percent CNF were comparable to those of boards prepared with 1 weight percent synthetic adhesive.
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Yang, Weiwei, Wanrong Ma et Xinyou Liu. « Evaluation of Deterioration Degree of Archaeological Wood from Luoyang Canal No. 1 Ancient Ship ». Forests 15, no 6 (31 mai 2024) : 963. http://dx.doi.org/10.3390/f15060963.
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This study provides a detailed investigation of archaeological wood samples from the Luoyang Canal No. 1 site, focusing on wood species identification, physical properties, mechanical property analyses, and morphological examination. The identified wood species, belonging to the Ulmus genus, exhibited a 43% decline in compressive strength in waterlogged environments. Further, the wood exhibited increased moisture content, higher porosity, reduced basic density, and elevated shrinkage rates, indicating a mild level of degradation. X-ray diffraction was employed for the observation of cellulose structure, and Fourier transform infrared spectroscopy (FT-IR) demonstrated significant removal of cellulose and hemicellulose components. These findings emphasize the importance of understanding wood degradation mechanisms to evaluate structural integrity and durability in guiding the development of effective preservation strategies for archaeological wood artifacts. Continued research and conservation are crucial to deepen our knowledge of wood deterioration processes and enhance the implementation of preservation techniques.
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Frodeson, Stefan, Anthony Ike Anukam, Jonas Berghel, Magnus Ståhl, Rasika Lasanthi Kudahettige Nilsson, Gunnar Henriksson et Elizabeth Bosede Aladejana. « Densification of Wood—Influence on Mechanical and Chemical Properties when 11 Naturally Occurring Substances in Wood Are Mixed with Beech and Pine ». Energies 14, no 18 (17 septembre 2021) : 5895. http://dx.doi.org/10.3390/en14185895.
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The need to increase the use of renewable biomasses for energy supply, such as fuel pellets is significant. However, different types of biomasses have different mechanical properties to be pelletized, which entails a limitation in available raw materials for pellet producers. Within this study eleven different pure substances from biomasses were separately mixed with European beech and Scots pine, to identify its impact on the densification process. Beech and pine pellets were used as control materials against their corresponding pellets mixed with substances representing: cellulose, hemicelluloses, other polysaccharides, lignin, protein, and extractives. The mechanical properties were investigated as well as FT-IR and SEM analyses on the pellets. The results showed that the addition of the substances xylan and galactan created the hardest pellets for both pine and beech and that adding extractives to wood affects pine more than beech in relation to hardness. The FT-IR data could not provide clear explanations as to the variation in hardness and springback behavior through the identification of major functional groups in each pellet. It can be concluded that biomass residues rich in xylan and galactan increase pellet quality in terms of strength and durability without affecting the production process.
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Pan, Shen, et Zhanyuan Chang. « WD-1D-VGG19-FEA : An Efficient Wood Defect Elastic Modulus Predictive Model ». Sensors 24, no 17 (28 août 2024) : 5572. http://dx.doi.org/10.3390/s24175572.
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As a mature non-destructive testing technology, near-infrared (NIR) spectroscopy can effectively identify and distinguish the structural characteristics of wood. The Wood Defect One-Dimensional Visual Geometry Group 19-Finite Element Analysis (WD-1D-VGG19-FEA) algorithm is used in this study. 1D-VGG19 classifies the near-infrared spectroscopy data to determine the knot area, fiber deviation area, transition area, and net wood area of the solid wood board surface and generates a two-dimensional image of the board surface through inversion. Then, the nonlinear three-dimensional model of wood with defects was established by using the inverse image, and the finite element analysis was carried out to predict the elastic modulus of wood. In the experiment, 270 points were selected from each of the four regions of the wood, totaling 1080 sets of near-infrared data, and the 1D-VGG19 model was used for classification. The results showed that the identification accuracy of the knot area was 95.1%, the fiber deviation area was 92.7%, the transition area was 90.2%, the net wood area was 100%, and the average accuracy was 94.5%. The error range of the elastic modulus prediction of the three-dimensional model established by the VGG19 classification model in the finite element analysis is between 2% and 10%, the root mean square error (RMSE) is about 598. 2, and the coefficient of determination (R2) is 0. 91. This study shows that the combination of the VGG19 algorithm and finite element analysis can accurately describe the nonlinear defect morphology of wood, thus establishing a more accurate prediction model of wood mechanical properties to maximize the use of wood mechanical properties.
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Kloiber, Michal, Mária Kotlínová et Jan Tippner. « Estimation of wood properties using pin pushing in method with various shapes of the penetration pin ». Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 57, no 2 (2009) : 53–60. http://dx.doi.org/10.11118/actaun200957020053.
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The existing penetration methods for the identification of the density of wood that forms a part of structures do not make it possible to describe the density in the entire element profile but only on its surface. However, wood density changes throughout the profile which affects the accuracy of the density determination. The instruments used until now based on the principle of a pin shot into the material thus needed to be supplemented with a test during which the pin would be pushed at least to the centre of the measured element. Pins of 3 mm in diameter were manufactured with a special jig fastening them to a universal testing machine. Using the testing machine, the force required to push the pin in was measured at a constant travel speed. It has been found out that the mechanical work needed for the pin penetration correlates very well with the wood density determined in the surroundings of the place where the pin was pushed in.
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Mertz, Mechtild, Sangeeta Gupta, Yutaka Hirako, Pimpim de Azevedo et Junji Sugiyama. « WOOD SELECTION OF ANCIENT TEMPLES IN THE SIKKIM HIMALAYAS ». IAWA Journal 35, no 4 (6 décembre 2014) : 444–62. http://dx.doi.org/10.1163/22941932-00000077.
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Microscopic wood identifications were performed on five Buddhist temple structures and on one secular building located in Sikkim, an Indian state in the Eastern Himalayas. In all, twenty wood species were identified, two of which – Michelia (Magnolia) doltsopa and Picea cf. spinulosa – were considered in more detail. Building type, specific physical and mechanical properties of the wood species, local availability, and religious considerations were apparently the leading criteria for timber selection.
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Bos, Frédéric, Laurent Le Magorou et Frédéric Rouger. « An approach to viscoelastic behaviour analysis of wood-based panels by an inverse method of characterisation ». Holzforschung 59, no 5 (1 septembre 2005) : 546–51. http://dx.doi.org/10.1515/hf.2005.090.
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Abstract The main objective of this paper is to propose an alternative method for viscoelastic characterisation of wood-based panels. Our approach, based on inverse identification methods, allows simultaneous estimation of the whole bending/torsion stiffness matrix of orthotropic plates. Elastic or viscoelastic characterisations are carried out according to the same protocol. The first step consists of optimisation of the experimental set-up, i.e., determination of the best localisation and intensity of the applied stresses and of the best position for boundary conditions. This step is realised for each type of panel using generic algorithms to obtain sensitivities satisfying the test for each stiffness matrix component. An identification procedure is then performed using a finite element program. The measurement of the whole displacement field (500×500 mm2) is made using an optical system. Validation of the elastic identification is carried out by comparison with the mechanical properties obtained from a vibrating test and a simulation tool. Non-conventional analysis of the viscoelastic behaviour of wood-based panels is illustrated for two particular plywood panels.
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Merli, Francesca, Elisa Belloni et Cinzia Buratti. « Production of eco-sustainable insulating panels by recovering wood waste : fabrication and preliminary experimental characterization of thermal and acoustic properties ». E3S Web of Conferences 197 (2020) : 08021. http://dx.doi.org/10.1051/e3sconf/202019708021.
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The work was developed in the ReScaLe FiAer project framework, funded by the Fondazione Cassa di Risparmio di Perugia. It is focused on the identification and collection of multiple high quality wood waste from a local window manufacturer. Three types of wood were available, from different tree species (pine, oak, and mahogany) and sizes (pieces of wood, mixed coarse chips, and mixed fine chips). Preliminary analyses were performed in order to evaluate the properties of the raw material. For each type of wood, eco-sustainable panels (300x300 mm2) were assembled by gluing. Multiple tests were carried out in order to identify the optimal mixtures and to ensure a good mechanical resistance with the minimum adhesive use. Panels were assembled by using vinyl glue, easily available and cheap, and flour glue, with a lower environmental impact and safe for people’s health. The thermal conductivity of the panels was measured by means of the Small Hot Box experimental apparatus: it varies in the 0.071-0.084 W/mK range, at an average temperature of 10°C, depending on the tree species and regardless of the type of adhesive used. Furthermore, 100-mm diameter cylindrical samples with two different thicknesses for each type of wood and glue were fabricated, in order to investigate their acoustic behaviour in an impedance tube. The use of flour glue improves the sound absorption and insulation performance of the samples.
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Fedyukov, Vladimir Ilyich, Ekaterina Yurevna Saldaeva, Maria Sergeyevna Chernova et Vasilii Yuryevich Chernov. « Research into Dendro-Acoustic Properties of Intro-duced Clones’ Wood as Material for Manufacturing Musical Instruments ». South-east European forestry 10, no 2 (3 novembre 2019) : 173–79. http://dx.doi.org/10.15177/seefor.19-18.
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Background and Purpose: Studies of the physical-mechanical and acoustic properties of maple wood as a potential material for musical instruments manufacturing are extremely scarce. Related to this, dendro-acoustic studies of maples introduced by geographic origin are of great practical importance in order to create target plantations with predicted technical quality of wood. Materials and Methods: Maples from abroad introduced by geographic origin into the Botanical Garden of the Volga State University of Technology of the Republic of Mari El of Russia were used for the research. For comparison, the Norway maple of local origin ( Acer platanoides L.) was selected. The studies were carried out by the frequency-amplitude method for determining Young's dynamic modulus and the acoustic constant of sound emission according to the criterion of academician N. Andreyev. Results: It was revealed that there are differences in the density and dendroacoustic indices of maple wood of local origin and maple trees introduced by geographic origin. Norway maple ( Acer platanoides L.) turned out to possess the largest acoustic constant characterizing the resonant properties of wood. Introduced maple trees, plane-tree maple ( Acer pseudoplatanus L.) and sugar maple ( Acer saccharinum L.) are only slightly inferior in terms of this indicator. Conclusions: The dendroacoustic properties of maple wood are generally much lower than that of resonant spruce. Consequently, the acoustic role of maple wood in the back plates of the violin and other string instruments is completely different than that of the top plate made from the resonant material of coniferous species. To reveal this difference in more detail, comparative studies and dendroacoustic identification of maple wood in blanks and musical instruments with different levels of acoustic characteristics are necessary.
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Silva, Larissa Barbosa Fernandes da, João Paulo Boff Almeida, Leonardo Vinícius Paixão Daciolo, Victor Almeida de Araújo, André Luís Christoforo et Francisco Antonio Rocco Lahr. « Strength classes of brazilian hardwoods for structural design ». Caderno Pedagógico 21, no 5 (10 mai 2024) : e3952. http://dx.doi.org/10.54033/cadpedv21n5-073.
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For the elaboration of projects on timber structures, the Brazilian standard (ABNT, in Portuguese Associação Brasileira de Normas Técnicas) 7190 (ABNT 1997) ensures the correct application of physical-mechanical properties according to strength classes of lignocellulosic materials. This procedure eliminates the need for botanical identification of woods, since these strength classes support the efficient utilization of a wide range of woody varieties available in Brazil. Due to high mechanical resistances, the hardwoods are usually applied for structural projects of timber construction. This Brazilian standard document prescribes four strength classes (C20, C30, C40 and C60) for these woods, which are determined by characteristic value from the compressive strength parallel to the grain (fc0,k). But, these classes were obtained from experimental outcomes using a few wood varieties. The reorganization of strength classes should result in the best use of mechanical potentials of woods since the updating of these categories leads to the optimization of structural projects for timber construction in order to reposition this biomaterial at even more competitive levels. In this context, the present study aims to verify the current strength classes of hardwoods and if they lead to a good allocation of the fc0,k characteristic values. Otherwise, new strength classes can be determined for better allocations for efficient structural uses. As a result, 56 hardwoods were considered using 672 experimental determinations. Statistically, the current categories can lead to 12,5 % of incorrectly allocated values. The inclusion of C50 and C70 classes allow greater representation for these categories, in order to optimize the use of the hardwoods given the new strength classes. These findings ought to support future revisions of this Brazilian standard document.
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Faggiano, Beatrice, Maria Rosaria Grippa et Bruno Calderoni. « Non-Destructive Tests and Bending Tests on Chestnut Structural Timber ». Advanced Materials Research 778 (septembre 2013) : 167–74. http://dx.doi.org/10.4028/www.scientific.net/amr.778.167.
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In the context of a more wide research study for in situ mechanical identification of ancient timber structures by non-destructive techniques, the paper illustrates the experimental activity developed on structural elements made of old chestnut timber, 4x4x76 cm size: 24 squared specimens were extracted by six elements in actual dimensions, already used in a previous tests campaign. Non-destructive (ND: hygrometric, sclerometric and resistographic) and destructive (D: bending) tests were performed, the latter according to UNI EN 408 (2004) standard, in order to assess the mechanical properties and the collapse mechanisms of chestnut timber. Data gathered are presented in detail and, NDT-DT correlations, obtained through a linear regression approach, are provided to predict wood density, strength and modulus of elasticity of the tested members.
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Agbayani, Mark Anthony R., Marissa A. Paglicawan, Marianito T. Margarito et Blessie A. Basilia. « Effects of Wood Flour Reinforcement on the Warpage and Compressive Strength of 3D Printed HDPEs ». Materials Science Forum 1085 (20 avril 2023) : 35–41. http://dx.doi.org/10.4028/p-4f7avg.
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The study involves the use of high density polyethylene (HDPE) as a filament for 3D printing. Considering the warpage and adhesion problem of HDPE on the build plate during 3D printing, this was addressed through the incorporation of wood flour compatibilized with styrene-ethylene-butylene-styrene grafted maleic anhydride (SEBS-gMAH). The composite wood-HDPE (cHDPE) was studied to observe warpage changes. Using different SEBS, heat bed parameters and identification of the suitable print heat beds for HDPE was conducted. Results from the mechanical testing show that the compressive strength and elastic force of virgin HDPE (vHDPE) increases with infill percentage, while the same properties for cHDPE increases up to 50% infill density/percentage then decreases as it approaches 100% infill percentage. Digital microscopy imaging shows that poor layer adhesion initiated the poor compressive performance of cHDPE. Warp studies reveal that wood flour significantly decreases warping of HDPE by 42.88% at 50% infill density. While different SEBS brands show similar effectiveness as heat beds in reducing warping of HDPE during printing.
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Adam, Laurentiu, et Dorina-Nicolina ISOPESCU. « PHYSICO-MECHANICAL PROPERTIES INVESTIGATION OF HEMPCRETE ». Journal of Applied Life Sciences and Environment 55, no 1(189) (2022) : 75–84. http://dx.doi.org/10.46909/alse-551047.
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Food, energy and construction are the three main domains in which different uses of industrial hemp confirm the role and importance that agriculture has in human life. In the current context with an increased need for energy efficiency and environmental protection, the attention of scientists is directed towards the identification of ecological construction materials, and a sustainable way of life, where the circular economy must become part of people’s living habits. The objective of the research was to analyze the thermo-mechanical properties of hempcrete. The goal is to determine a point of reference for future studies that will aim to adapt the agreed compositions to the particularities of the raw material obtained locally. Measurements were determined through laboratory tests, performed on specimens obtained using, for the base material, the woody part of industrial hemp, and for the binder, a mixture consisting of hydrated lime and Portland cement. The results place the construction materials made from hemp vegetable waste in the group of heat-insulating products characterized by low specific weight and thermal transfer coefficients, according with conventional insulating materials, with values between those of polyurethane foam and autoclaved cellular concrete.
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Xavier, José, Stéphane Avril, Fabrice Pierron et José Morais. « Novel experimental approach for longitudinal-radial stiffness characterisation of clear wood by a single test ». Holzforschung 61, no 5 (1 août 2007) : 573–81. http://dx.doi.org/10.1515/hf.2007.083.
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Abstract Experimental results obtained from maritime pine (Pinus pinaster Ait.) wood are presented for the characterisation of all LR=(1,2) orthotropic stiffness parameters of clear wood specimens by a single test. The approach relies on application of the virtual field method (VFM) to a rectangular specimen loaded in the Iosipescu fixture. The displacement field over the gauge surface of the specimen is measured by the grid method. Two configurations are investigated: (1) with grain aligned along the specimen length (0° configuration) and (2) with grain at 45°. For the 0° configuration, only the parameters Q 11 and Q 66 are correctly identified, with coefficients of variation of the same order of magnitude as those obtained from reference tensile and shear tests. Better identification is obtained for the 45° configuration, for which only the parameter Q 12 exhibits large scatter. This improvement results from a more balanced influence of all stiffness parameters on the response of the 45° specimen. However, all stiffness parameters identified were systematically underestimated by approximately 30% in comparison to reference values. This deviation is due to the vertical spatial variation of the mechanical properties of wood within the stem. Literature data confirm this interpretation.
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Ali, Bimkubwa Seif, Juan Jose Castro, Shogo Omi et Karishma Nazimi. « Preserving the Past : Investigating Zanzibar’s Ancient Construction Materials for Sustainable Heritage Conservation ». Buildings 14, no 7 (11 juillet 2024) : 2129. http://dx.doi.org/10.3390/buildings14072129.
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The architectural treasures of Zanzibar’s Stone Town, echoing the footprints of ancient civilizations, face an imminent threat of heritage loss due to accelerated material degradation. This underscores the urgent need for an intrinsic examination of building material properties to enhance existing restoration guidelines and effectively safeguard the historical legacy. This study is the first significant step for the extensive procurement of samples to investigate the physical, mechanical, and chemical properties of deteriorating coral stones, mortar, and wood material of Zanzibar’s Stone Town. The results indicate considerable water absorption and varying porosity and densities, highlighting the significant water retention and susceptibility of marine environmental factors. The compressive strength (CS) for coral stone, mortar, and wood falls under 7.6 MPa to 12.2 MPa, 0.5 to 0.9 MPa, and 52.9 to 69.3 MPa, revealing the heterogenous characteristics across the samples. The flexural strength of coral stone and wood was found to be from 2.0 MPa to 3.4 and 72.1 MPa to 98.6 MPa, indicating a high susceptibility to breakage and fracture. Meanwhile, Ultra Pulse Velocity (UPV) averages 1668 to 2070 m/s, revealing void ranges in building materials. Chemical analysis, including X-ray diffraction (XRD) and X-ray fluorescence (XRF), demonstrates higher CaO content in coral stone and mortar, with the predominant mineral aragonite indicating vulnerability to rapid chemical attacks. These results can significantly contribute to future modifications and improvements in restoration guidelines by facilitating the identification and utilization of appropriate materials’ properties. This ensures a high level of compatibility and promotes the sustainable conservation of Stone Town’s architectural heritage.
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Martínez, Roberto D., Luis-Alfonso Basterra, Luis Acuña et José-Antonio Balmori. « Morphology and Material Composition of the Mouthparts of Stromatium unicolor Olivier 1795 (Coleoptera : Cerambycidae) for Bionic Application ». Forests 11, no 7 (27 juin 2020) : 715. http://dx.doi.org/10.3390/f11070715.
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Research Highlights: The novelty of this study is the deep analysis of the morphologic, geometric and mechanical performance of longhorn beetle larvae mouthparts. Furthermore, a metal nano identification of jaw reinforced parts was made. Background and Objectives: Analysis of insect mechanical properties has shown an important application in the develop of bionic technologies such as new materials, industrial machines and structural concepts. This study aims to determine the mechanical and geometric properties of longhorn beetle (Stromatium unicolor Olivier 1795) larvae mouthparts to improve the development of innovative cutting tools. In addition, this study obtains a nano identification of metals in the cuticle of the mouthparts, which will enable the development of new nontoxic and sustainable preservation agents against xylophagous insects based on nanoparticles. Materials and Methods: five third-larval-stage samples of Stromatium unicolor were used to study its mandible morphologic, geometric and mechanical properties. To this end, mouthparts were analyzed by several microscopic techniques using a scanning electron microscope, a stereomicroscope and an optical microscope. Composition analysis was performed using with two Analytical-Inca X-ray detectors, dispersive energy spectroscopy and dispersive wavelength spectroscopy. Results: The main geometric parameters of the insect jaw are the edge angle (β = 77.3°), maximum path depth of the insect (120 μm), length (800 µm) and mouthpart movement, which were identified and measured. The chemical analysis results of the jaw tissues shows the presence of zinc and manganese. Conclusions: The geometry and angles of the mouthparts can be applied in the fabrication of bionic self-sharpening cutting tools. Molecular compounds that form the reinforcing elements in the jaws can be used to develop wood preservatives based on nanometals and metal absorption and metabolism inhibitors.
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Pereira, J., J. Xavier, J. Morais et J. Lousada. « Assessing wood quality by spatial variation of elastic properties within the stem : Case study of Pinus pinaster in the transverse plane ». Canadian Journal of Forest Research 44, no 2 (février 2014) : 107–17. http://dx.doi.org/10.1139/cjfr-2013-0207.
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The wood quality of maritime pine (Pinus pinaster Ait.) is discussed in view of spatial variability of density, annual growth ring characteristics, and transverse elastic properties within and among five basal logs. X-ray microdensitometry measurements are carried out to assess both average (Dmean) and local (DEW, DLW) densities of annual growth rings, as well as the respective dimensions (EWW, LWW) and fractions of earlywood (EW) and latewood (LW) layers. Mechanical tensile tests on a set of specimens with different ring orientation are proposed. Transverse elastic properties are determined by coupling an inverse identification strategy with full-field deformation measurements provided by digital image correlation. For a suitable range of off-axis angles, this method allows the simultaneous characterisation of the four orthotropic elastic properties in the RT plane: ER, ET, νRT, and GRT. These results are found in agreement with reference values. From the sampled specimens among logs, ER and GRT are robustly identified in all cases and therefore are selected for further analysis of structure-properties relationships. Correlations between Dmean and ER and GRT are positive and statistically significant. Furthermore, other parameters also show significant correlations with the elastic constants, especially Dmin, LWW, and DEW.
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Rodriguez, Alice, Kaushik Yanamandra, Lukasz Witek, Zhong Wang, Rakesh K. Behera et Radu Iovita. « The effect of worked material hardness on stone tool wear ». PLOS ONE 17, no 10 (20 octobre 2022) : e0276166. http://dx.doi.org/10.1371/journal.pone.0276166.
Texte intégralRésumé :
The identification of ancient worked materials is one of the fundamental goals of lithic use wear analysis and one of the most important parts of understanding how stone tools were used in the past. Given the documented overlaps in wear patterns generated by different materials, it is imperative to understand how individual materials’ mechanical properties might influence wear formation. Because isolating physical parameters and measuring their change is necessary for such an endeavor, controlled (rather than replicative) experiments combined with objective measurements of surface topography are necessary to better grasp how surface modifications formed on stone tools. Therefore, we used a tribometer to wear natural flint surfaces against five materials (bone, antler, beech wood, spruce wood, and ivory) under the same force, and speed, over one, three, and five hours. The study aimed to test if there is a correlation between surface modifications and the hardness of the worked material. We measured each raw material’s hardness using a nano-indentation test, and we compared the surface texture of the flint bits using a 3D optical profilometer. The interfacial detritus powder was analyzed with a scanning electron microscope to look for abraded flint particles. We demonstrate that, contrary to expectation, softer materials, such as wood, create a smoother surface than hard ones, such as ivory.
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Lv, Yunlei, Yaqiu Liu, Xiang Li, Lina Lu et Adil Malik. « Automated Shape Correction for Wood Composites in Continuous Pressing ». Forests 15, no 7 (27 juin 2024) : 1118. http://dx.doi.org/10.3390/f15071118.
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Abstract: The effective and comprehensive utilization of forest resources has become the theme of the global “dual-carbon strategy”. Forestry restructured wood is a kind of wood-based panel made of wood-based fiber composite material by high-temperature and high-pressure restructuring–molding, and has become an important material in the field of construction, furniture manufacturing, as well as derivative processing for its excellent physical and mechanical properties, decorative properties, and processing performance. Taking Medium Density Fiberboard (MDF) as the recombinant material as the research object, an event-triggered synergetic control mechanism based on interventional three-way decision making is proposed for the viscoelastic multi-field coupling-distributed agile control of the “fixed thickness section” in the MDF continuous flat-pressing process, where some typical quality control problems of complex plate shape deviations including thickness, slope, depression, and bump tend to occur. Firstly, the idea of constructing the industrial event information of continuous hot pressing based on information granulation is proposed, and the information granulation model of the viscoelastic plate shape process mechanism is established by combining the multi-field coupling effect. Secondly, an FMEA-based cyber granular method for diagnosing and controlling the plate thickness diagnosis and control failure information expression of continuous flat pressing is proposed for the problems of plate thickness control failure and plate thickness deviation defect elimination that are prone to occur in the continuous flat-pressing process. The precise control of the plate thickness in the production process is realized based on event-triggered control to achieve the intelligent identification and processing of the various types of faults. The application test is conducted in the international mainstream production line of a certain type of continuous hot-pressing equipment for the production of 18 mm plate thickness; the synergistic effect is basically synchronized after 3 s, the control accuracy reaches 30%, and the average value of the internal bond strength is 1.40, which ensures the integrity of the slab. Practical tests show that the method in the actual production is feasible and effective, with detection and control accuracy of up to ± 0.05 mm, indicating that in the production of E0- and E1-level products, the rate of superior products can reach more than 95%.
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Yanez, Sergio, Constanza Márquez, Benjamín Valenzuela et Cristina Alejandra Villamar-Ayala. « A Bibliometric-Statistical Review of Organic Residues as Cementitious Building Materials ». Buildings 12, no 5 (5 mai 2022) : 597. http://dx.doi.org/10.3390/buildings12050597.
Texte intégralRésumé :
Climate deterioration and environmental pollution has been widely studied by a wide scientific community. The effects of the ecosystem deterioration impacts directly to human activities. In this scenario, the building industry has increased the pressure on proposing new materials to replace the cementicious component and natural resources (water, sand, gravel, and limestone) on mortar and concrete to reverse this trend. To this end, organic residues can offer opportunities as an available alternative for construction applications. Therefore, this paper aims to broaden the scope of research in this field by investigating the potential use of organic residues as cementicious building material based on bibliometric-statistical analysis using scientific information. A preliminary bibliometric analysis using VOSviewer was carried out to define the keywords co-ocurrence from Scopus database. Type of organic material, constructive use, and its properties (physicochemical, mechanical, and thermal) were extracted from scientific publications. Then, a systematic analysis criteria was defined to limit the scope of the study. Finally, statistical variance analysis and multiple correlation for identifying constructive application were applied. From the co-ocurrence analysis of keywords, we determined that 54% of the selected scientific publications were closely related to the scope of this study. State-of-the-art study established that related researches grew exponentially at a rate of about 30%/year. Moreover, scientific publications reported the use of a wide variety of organic residues, such as wheat, paper, hemp, rice, wood, molluscs, olive, coconut, among others. Mainly, agricultural residues (82%) with building applications related to structural concrete, mortar, bricks, and blocks, had been evaluated. Physicochemical properties from organic residues (extractives content, lignin content, and density) were correlated to mechanical (compressive, flexural and tensile strength) and thermal properties (thermal conductivity). The identification of the physicochemical properties of the organic residues allow us to predict the mechanical and thermal behavior of the material with residues. In summary, agricultural residues are the most promising organic building material due to their abundance and lignin content, exhibiting better mechanic and thermal properties than any other organic residues.
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Ji, Min, Wei Zhang, Xingliang Diao, Guofu Wang et Hu Miao. « Intelligent Automation Manufacturing for Betula Solid Timber Based on Machine Vision Detection and Optimization Grading System Applied to Building Materials ». Forests 14, no 7 (24 juillet 2023) : 1510. http://dx.doi.org/10.3390/f14071510.
Texte intégralRésumé :
Wood material is the foundation of wood structure architecture, and its production technology and equipment technology decide the development and upgrading of modern wood structure architecture. Aiming at the problems of low automation degree, low material utilization rate, low production efficiency and high labor costs in the process of traditional wood processing, we explore the integration and innovation of the traditional wood processing industry and modern industrial Internet information technology on the basis of studying the properties of Betula (Betula costata) solid wood materials, wood comprehensive utilization rate, wood structure component development and processing technology requirements, and form an intelligent, automatic and industrial production mode for building materials. Through technology and methods such as mechanical design, automation technology, machine vision, deep learning, optimization algorithm, electronic design automation, computer aided manufacturing, etc., the key technologies of intelligent automatic optimization of wood materials were studied, and intelligent automatic production lines of Betula species identification, log optimization sawing, solid timber longitudinal multiblade sawing, sawn timber quality detection and solid timber optimizing cross-cuts are built. Based on the machine vision method, features are extracted; a tree species, defect classification and recognition model database is established; an image processing algorithm with high recognition accuracy, as well as fast processing speed and high robustness are studied; non-destructive testing and classification methods of machine vision are optimized; key problems of online rapid classification, detection and optimization of sawing are solved and production quality and processing efficiency are improved. Finally, the timber defect detection accuracy and Betula timber yield are analyzed, and the comprehensive utilization value of optimized sawing timber is compared with the comprehensive utilization value of manually marking sawing timber. The processing cost and efficiency of Betula sawing timber with an intelligent automatic production line are calculated. The test results show that the average detection accuracy of timber defect type, size and location is 89.69%, 89.69%, 92.25% and 82.29%, respectively, and the detection stability is high. By adopting intelligent automatic detection, classification and optimization sawing production line of wood, the comprehensive utilization value of optimized sawing timber is 14.13% higher than that of manual marking sawing timber, and 16,089.29 m3 more building materials can be processed annually. In the process of intelligent automatic wood processing, the intelligent detection system is used to detect defects, improve production performance and production efficiency and reduce labor costs. Compared with the traditional wood processing process, the method studied in this paper is improved to optimize the production line processing performance and processing technology. The research and development of an intelligent automatic production system for solid wood can promote the application and development of an automatic industrial production mode for sawn timber for the wood structure construction industry, deepen the integration of artificial intelligence technology, Internet technology and the whole wood processing industry and lead the upgrading of building materials for wood structures to an intelligent manufacturing production mode.
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Bereziuk, Iryna, Olena Holyk et Valentyn Soldatenko. « Dynamic Design of Optimal Stochastic Stabilization System of Cutting Power on a Band Saw Machine ». Central Ukrainian Scientific Bulletin. Technical Sciences, no 3(34) (octobre 2020) : 169–74. http://dx.doi.org/10.32515/2664-262x.2020.3(34).169-174.
Texte intégralRésumé :
The article is devoted to the development of methodological foundations for constructing an optimal system of stochastic stabilization of cutting power based on the results of structural identification of models of the dynamics of the system '' woodworking machine-cutting process '' and uncontrolled disturbance. In order to solve the problem of structural identification of the '' woodworking machine-cutting process ' system and the disturbance acting in the process of wood-cutting, the article proposes a special technology, the use of which made it possible to determine the transfer function of the '' woodworking machine-cutting process '' and estimate the spectral density of the disturbance acting during the processing. It has been established that when the physical and mechanical properties of wood and the state of the cutting tool change, the structure of the transfer function and spectral density does not change, but only the parameters change.As a result of solving the synthesis problem, the structure and parameters of the optimal controller are determined, which ensures the specified quality of the processed surface with minimal energy consumption. To assess the quality of control, it is proposed to use a quadratic criterion, which is the sum of two weighted variances of the stator current deviation of the main motion motor (characterizes energy costs) and the variance of the feed drive speed control signal.Studies of the robust stability of the optimal system with the obtained controller under the influence of unstructured disturbances made it possible to determine the class and estimate the maximum norms of unstructured disturbances at which the system maintains stability and a given control quality. The use of the proposed approach to the construction of an optimal system of stochastic stabilization of cutting power makes it possible to achieve a reduction in energy costs by 12% for a given quality of the processed surface by increasing the stabilization accuracy by two orders of magnitude.
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Guo, Yong, Shiliu Zhu, Yuxia Chen et Dagang Li. « Analysis and Identification of the Mechanism of Damage and Fracture of High-Filled Wood Fiber/Recycled High-Density Polyethylene Composites ». Polymers 11, no 1 (18 janvier 2019) : 170. http://dx.doi.org/10.3390/polym11010170.
Texte intégralRésumé :
The damage and fracture of fiber reinforced polymer composites are vital constraints in their applications. To understand the mechanism of damage of wood fiber (WF) reinforced high density polyethylene (HDPE) composites, we used waste WF and recycled HDPE (Re-HDPE) as the raw materials and prepared high-filled WF/Re-HDPE composites via extrusion. The damage and fracture mode and failure mechanism of the composites with different WF contents (50%, 60%, and 70%) was studied under a three-point bending test by combining the acoustic emission (AE) technique and scanning electron microscope (SEM) analysis. The results show that AE technology can better assist in understanding the progress of damage and fracture process of WF/Re-HDPE composites, and determine the damage degree, damage accumulation, and damage mode. The damage and fracture process of the composites presents three main stages: the appearance of initial damage, damage accumulation, and destructive damage to fracture. The matrix deformation, fiber breakage, interface delamination, fiber-matrix debonding, fiber pull-out, and matrix cracking were the dominant modes for the damage of high-filled WF/Re-HDPE composites under bending load, and the AE signal changed in different damage stages and damage modes. In addition, the WF content and repeated loading had a significant influence on the composite’s damage and fracture. The 50% and 60% WF/Re-HDPE composites produced irreversible damage when repeated load exceeded 75% of the maximum load, while 25% of the maximum load could cause irreversible damage for 70% WF/Re-HDPE composites. The damage was accumulated owing to repeated loading and the mechanical properties of the composites were seriously affected.
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Pereira, João Luís, José Xavier, Bahman Ghiassi, José Lousada et José Morais. « On the identification of earlywood and latewood radial elastic modulus of Pinus pinaster by digital image correlation : A parametric analysis ». Journal of Strain Analysis for Engineering Design 53, no 8 (11 juillet 2018) : 566–74. http://dx.doi.org/10.1177/0309324718786351.
Texte intégralRésumé :
This work addresses the reconstruction of strain gradient fields at the wood growth ring scale from full-field deformation measurements provided by digital image correlation. Moreover, the spatial distribution of the earlywood and latewood radial modulus of elasticity is assessed. Meso-scale tensile tests are carried out on Pinus pinaster Ait. wooden specimens oriented in the radial–tangential plane under quasi-static loading conditions. A parametric analysis of the two-dimensional digital image correlation extrinsic and intrinsic setting parameters is performed, in a balance between spatial resolution and resolution. It is shown that the parametric module is an effective way to quantitatively support the choice of digital image correlation parameters in the presence of the high deformation gradient fields generated by the structure–property relationships at the scale of observation. Under the assumption of a uniaxial tensile stress state, the spatial distribution of the radial elastic modulus across the growth rings is obtained. It is observed that the ratio of the radial modulus of elasticity between latewood and earlywood tissues can vary significantly as a function of the digital image correlation parameters. It is pointed out, however, that a convergence value can be systematically established. Effectively, earlywood and latewood stress–strain curves are obtained and elastic properties are determined assuming the converged digital image correlation setting parameters.
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Hristian, Liliana, Maria Magdalena Ostafe, Ionut Dulgheru, Liliana Buhu, Adrian Buhu et Daniela Negru. « Identification of influence factors on physical-mechanical properties, using the principal component analysis, in selecting the textile fabrics for the clothing products ». Industria Textila 71, no 05 (28 octobre 2020) : 438–45. http://dx.doi.org/10.35530/it.071.05.1754.
Texte intégralRésumé :
The paper aims to highlight the correlations between the physical-mechanical properties of woven fabrics made of combed wool yarn with different fibrous compositions, using the Principal Component Analysis (PCA) method. Based on the information on each fabric/assortment group, it is found that four main factors were extracted: durability, comfort, production price and fabric design. The extracted components explain 92% of the variability of the twelve initial inter-correlated variables, so that we can considerably reduce the complexity of the data configured using these components, with only 8% loss of information. This technique that follows the controlled reduction of the number of variables can be used subsequently for modelling the physical-mechanical properties of the fabrics and for selecting the most suitable fabrics to satisfy the requirements of a particular field of use
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Duca, Daniele, Andrea Pizzi, Manuela Mancini, Giorgio Rossini, Chiara Mengarelli, Alessio Ilari, Giulia Lucesoli, Giuseppe Toscano et Ester Foppa Pedretti. « Fast measurement by infrared spectroscopy as support to woody biofuels quality determination ». Journal of Agricultural Engineering 47, no 1 (8 mars 2016) : 17. http://dx.doi.org/10.4081/jae.2016.499.
Texte intégralRésumé :
The increase in the demand for energy supply during the past few decades has brought and will bring to a growth in the utilisation of renewable resources, in particular of solid biomasses. Considering the variability in the properties of biomass and the globalisation of the timber market, a chemical and physical characterisation is essential to determine the biomass quality. The specific international standards on solid biofuels (ISO 17225 series) describe proper specification and classification of wood chip and pellet, to ensure appropriate quality. Moreover, standard requires information about origin and source of the biomass, normally only to be declared by the producers. In order to fulfill the requirements for the biomass quality, the origin and the source should be assessed, even if currently is hard to determine, in particular on milled or densified biomass. Infrared spectroscopy can provide information on the biomass at the chemical level, directly linked also to its origin and source. This technique is fast and not destructive thus suitable also for online monitoring along the biofuel production chain. In this study, 60 samples belonging to 8 different species were collected and related spectra were acquired using a Fourier transform infrared (IR) spectrometer equipped with a module for solid analysis and analysed by principal component analysis. The results obtained show that the method is very efficient in the identification between coniferous and deciduous wood (99% confidence level) and good results were obtained in the recognition of coniferous/deciduous mixtures, too. Nevertheless, some clear differences have been also noted among intra-class grouping, but additional tests should be carried out. This technique can provide useful information to solid biofuel stakeholders about wood quality and origin, important especially for sustainability issues. Further work will be oriented to the development of IR methodologies for the fast measurement of other important biomass parameters (<em>e.g.</em>, ash content, high calorific value, nitrogen content, <em>etc</em>.).
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ADASM, Laurentiu, Dorina-Nicolina ISOPESCU, Loredana JUDELE, Roxana Dana BUCUR et Daniel LEPADATU. « STATISTICAL ANALYSIS OF PRELIMINARY STUDIES FOR HEMP CONCRETE ». Journal of Applied Life Sciences and Environment 55, no 2 (190) (17 janvier 2023) : 145–58. http://dx.doi.org/10.46909/alse-552052.
Texte intégralRésumé :
Waste is a major worldwide problem and its recycling has become mandatory in the current context of the decrease in natural resources. The management of recyclable waste improves the efficiency of any economic activities and the impact on the environment decreases proportionally to the quantities reused. With a significant impact on carbon dioxide emissions, the construction sector is one of the largest consumers of energy and raw materials. Hemp, and other biomass waste, are by-products in agriculture, making important contributions to the development of ecological materials by incorporating important quantities of such recyclable waste. This paper presents a series of different hemp concrete compositions that aim to obtain the optimum ratio between the binder and hemp shiv, in order to determine the inflection point towards which the delimitation can be made between insulating materials and materials with improved mechanical resistance. The importance of the work is given by the fact that, until now, the optimal proportion between the binder and hemp wood chips has not been demonstrated. This turning point must be justified by a variation of the mechanical resistance or a variation of the heat transfer coefficient, through the conductivity of the obtained samples. After preliminary testing, the statistical analysis will allow identification of the specific quantities needed to improve the physical-mechanical performance of the hemp-concrete recipe. Thus, by adding a justified amount of binder, an ecological material based on vegetable waste from agricultural crops is obtained. The material will have thermo-mechanical properties designed for a specific situation, required by the minimum performance imposed by the destination for which it will be made.
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Wei, Lixian, Xin Zhao, Xiaoyan Gu, Jiahui Peng, Wenjuan Song, Bin Deng, Ying Cao et Shanglian Hu. « Genome-Wide Identification and Expression Analysis of Dendrocalamus farinosus CCoAOMT Gene Family and the Role of DfCCoAOMT14 Involved in Lignin Synthesis ». International Journal of Molecular Sciences 24, no 10 (18 mai 2023) : 8965. http://dx.doi.org/10.3390/ijms24108965.
Texte intégralRésumé :
As the main component of plant cell walls, lignin can not only provide mechanical strength and physical defense for plants, but can also be an important indicator affecting the properties and quality of wood and bamboo. Dendrocalamus farinosus is an important economic bamboo species for both shoots and timber in southwest China, with the advantages of fast growth, high yield and slender fiber. Caffeoyl-coenzyme A-O-methyltransferase (CCoAOMT) is a key rate-limiting enzyme in the lignin biosynthesis pathway, but little is known about it in D. farinosus. Here, a total of 17 DfCCoAOMT genes were identified based on the D. farinosus whole genome. DfCCoAOMT1/14/15/16 were homologs of AtCCoAOMT1. DfCCoAOMT6/9/14/15/16 were highly expressed in stems of D. farinosus; this is consistent with the trend of lignin accumulation during bamboo shoot elongation, especially DfCCoAOMT14. The analysis of promoter cis-acting elements suggested that DfCCoAOMTs might be important for photosynthesis, ABA/MeJA responses, drought stress and lignin synthesis. We then confirmed that the expression levels of DfCCoAOMT2/5/6/8/9/14/15 were regulated by ABA/MeJA signaling. In addition, overexpression of DfCCoAOMT14 in transgenic plants significantly increased the lignin content, xylem thickness and drought resistance of plants. Our findings revealed that DfCCoAOMT14 can be a candidate gene that is involved in the drought response and lignin synthesis pathway in plants, which could contribute to the genetic improvement of many important traits in D. farinosus and other species.
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Galán-Marín, C., C. Rivera-Gómez et F. Bradley. « Ultrasonic, Molecular and Mechanical Testing Diagnostics in Natural Fibre Reinforced, Polymer-Stabilized Earth Blocks ». International Journal of Polymer Science 2013 (2013) : 1–10. http://dx.doi.org/10.1155/2013/130582.
Texte intégralRésumé :
The aim of this research study was to evaluate the influence of utilising natural polymers as a form of soil stabilization, in order to assess their potential for use in building applications. Mixtures were stabilized with a natural polymer (alginate) and reinforced with wool fibres in order to improve the overall compressive and flexural strength of a series of composite materials. Ultrasonic pulse velocity (UPV) and mechanical strength testing techniques were then used to measure the porous properties of the manufactured natural polymer-soil composites, which were formed into earth blocks. Mechanical tests were carried out for three different clays which showed that the polymer increased the mechanical resistance of the samples to varying degrees, depending on the plasticity index of each soil. Variation in soil grain size distributions and Atterberg limits were assessed and chemical compositions were studied and compared. X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), and energy dispersive X-ray fluorescence (EDXRF) techniques were all used in conjunction with qualitative identification of the aggregates. Ultrasonic wave propagation was found to be a useful technique for assisting in the determination of soil shrinkage characteristics and fibre-soil adherence capacity and UPV results correlated well with the measured mechanical properties.
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Kumar, Chandan, Adam Redman, William Leggate, Robert L. McGavin et Tony Dakin. « Assessment of the application of a SMART THUMPER™ as a low-cost and portable device used for stiffness estimation of timber products ». BioResources 16, no 3 (7 juillet 2021) : 5838–61. http://dx.doi.org/10.15376/biores.16.3.5838-5861.
Texte intégralRésumé :
Non-destructive evaluation methods for timber stiffness are gaining increased interest as an alternative to static testing since they can be fast, cost-effective, and transportable, as well as non-destructive. The objective of this study was to evaluate the accuracy and limitations of a newly developed smartphone application (SMART THUMPER™) for the non-destructive evaluation of timber stiffness properties. The study determined the effect of the length, density (species), and cross-section sizes of the timber samples on the stiffness results. The results were compared to beam identification by non-destructive grading (BING©), an existing commercial non-destructive testing technology for evaluating the mechanical quality of wood and other materials. It was found that the application can be used to reliably estimate the stiffness of various timber products with a resonance frequency value below 2000 Hz. Frequencies greater than 2000 Hz were found to induce errors due to the smartphone microphone, which is engineered to acquire a lower frequency range. A reliability matrix providing an indication of the accuracy of SMART THUMPER™ estimation was presented, which may also prove useful in selecting appropriate sample lengths prior to testing. The sample length or dimensions can be manipulated to lower the frequency, and hence, to improve the results.
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GARCÍA-MARTÍNEZ, MIGUEL A., TERESA TERRAZAS, DANIEL SÁNCHEZ, PABLO CARRILLO-REYES et EDUARDO RUIZ-SANCHEZ. « Culm anatomy of the genus Otatea (Poaceae, Bambusoideae, Bambuseae, Guaduinae) as a contribution to Mexican species identification ». Phytotaxa 609, no 2 (22 août 2023) : 75–102. http://dx.doi.org/10.11646/phytotaxa.609.2.1.
Texte intégralRésumé :
Otatea is a Neotropical woody bamboo genus with thirteen described species. It is distributed from Mexico to Central America and northeastern Colombia. In Mexico, the archaeological evidence suggests that the culms of Otatea have been used for centuries by some ethnic groups. It is important to explore morphological and anatomical characters for species identification in woody bamboos as consequence of its monocarpic nature. Most studies on culm anatomy are centered on commercially used species describing their physical and mechanical properties. The aim of this work was to find culm anatomical characters with taxonomic value. To perform this, we collected internode samples from adult plants at mid culm of 15 specimens that represent 10 described species and two putative new species of Otatea. Our results include descriptions of culm anatomy at a cross section accompanied with images that detail all the structures measured and described. Additionally, we elaborate a key based on anatomical characters. This contribution is the first to explore culm anatomy of the genus Otatea in search for characters with taxonomic value, providing useful evidence for species identification, including samples from archaeological sites.
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Parlato, Monica C. M., Simona M. C. Porto, Carmen Galán-Marín, Carlos Alberto Rivera-Gómez, Massimo Cuomo et Francesco Nocera. « Thermal Performance, Microstructure Analysis and Strength Characterisation of Agro-Waste Reinforced Soil Materials ». Sustainability 15, no 15 (26 juillet 2023) : 11543. http://dx.doi.org/10.3390/su151511543.
Texte intégralRésumé :
The use of raw-earth materials reinforced by natural fibres, i.e., livestock waste in the form of greasy wool, represents an eco-friendly alternative for a variety of construction applications. This proposal is based on the analysis of unfired adobe blocks stabilised with wool fibres for use as both structural and non-structural building materials. The influence of fibre length on the thermophysical and mechanical properties of the tested material was investigated. The thermal conductivity coefficient (λ) of raw-earth samples was assessed by following three different test setting procedures (T = 20 °C, and HR at 30%, 50%, and 70%), with the aim to evaluate the effects of different fibre lengths in the raw-earth mix. Samples reinforced by fibres 20 mm in length exhibited the lowest thermal conductivity coefficient (λ = 0.719 W/mK) obtained by a test reproducing typical indoor conditions within the Mediterranean area, i.e., T = 20 °C, and HR 50%. The best mechanical performance was exhibited by samples reinforced by fibres 40 mm in length, with a flexural and compression strength of 0.88 MPa and 2.97 MPa, respectively. The microstructure of these biocomposites was also examined with a scanning electron microscope (SEM) and an energy dispersive X-ray (EDX) to qualitatively evaluate the variation of thermal and mechanical properties due to the different adhesion among the fibres and the soil. The experimental data show good efficiency and a significant improvement in the behaviour of these materials compared to the control samples. The evaluation of the results, with the length of the fibres being the only variable of the analysed samples, allowed for the identification of the mix suitable for the best mechanical and thermal performances, depending on the final use of the material.
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Castro-Triguero, Rafael, Enrique Garcia-Macias, Erick Saavedra Flores, M. I. Friswell et Rafael Gallego. « Multi-scale model updating of a timber footbridge using experimental vibration data ». Engineering Computations 34, no 3 (2 mai 2017) : 754–80. http://dx.doi.org/10.1108/ec-09-2015-0284.
Texte intégralRésumé :
Purpose The purpose of this paper is to capture the actual structural behavior of the longest timber footbridge in Spain by means of a multi-scale model updating approach in conjunction with ambient vibration tests. Design/methodology/approach In a first stage, a numerical pre-test analysis of the full bridge is performed, using standard beam-type finite elements with isotropic material properties. This approach offers a first structural model in which optimal sensor placement (OSP) methodologies are applied to improve the system identification process. In particular, the effective independence (EFI) method is used to determine the optimal locations of a set of sensors. Ambient vibration tests are conducted to determine experimentally the modal characteristics of the structure. The identified modal parameters are compared with those values obtained from this preliminary model. To improve the accuracy of the numerical predictions, the material response is modeled by means of a homogenization-based multi-scale computational approach. In a second stage, the structure is modeled by means of three-dimensional solid elements with the above material definition, capturing realistically the full orthotropic mechanical properties of wood. A genetic algorithm (GA) technique is adopted to calibrate the micromechanical parameters which are either not well-known or susceptible to considerable variations when measured experimentally. Findings An overall good agreement is found between the results of the updated numerical simulations and the corresponding experimental measurements. The longitudinal and transverse Young's moduli, sliding and rolling shear moduli, density and natural frequencies are computed by the present approach. The obtained results reveal the potential predictive capabilities of the present GA/multi-scale/experimental approach to capture accurately the actual behavior of complex materials and structures. Originality/value The uniqueness and importance of this structure leads to an intensive study of its structural behavior. Ambient vibration tests are carried out under environmental excitation. Extraction of modal parameters is obtained from output-only experimental data. The EFI methodology is applied for the OSP on a large-scale structure. Information coming from several length scales, from sub-micrometer dimensions to macroscopic scales, is included in the material definition. The strong differences found between the stiffness along the longitudinal and transverse directions of wood lumbers are incorporated in the structural model. A multi-scale model updating approach is carried out by means of a GA technique to calibrate the micromechanical parameters which are either not well-known or susceptible to considerable variations when measured experimentally.
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Periolatto, Monica, Franco Ferrero, Mirco Giansetti, Raffaella Mossotti et Riccardo Innocenti. « Influence of protease on dyeing of wool with acid dyes ». Open Chemistry 9, no 1 (1 février 2011) : 157–64. http://dx.doi.org/10.2478/s11532-010-0133-9.
Texte intégralRésumé :
AbstractThe application of enzymes in the wool dyeing process is an important research goal in order to reduce the environmental impact and costs of this finishing process. The work has focused on the possibility of reducing the temperature of conventional dyeing, using an enzymatic pretreatment with a neutral protease to improve the diffusion of the dye into the fibers. After the identification of the optimal dyeing process, the study goes on transferring the method to an industrial application. For this reason the influence of a leveling agent added to the dyeing bath was considered and further tests with an industrial dyeing recipe were performed. In order to evaluate possible fiber damage, samples treated with enzyme were observed by scanning electron microscopy (SEM) and analyzed by gel electrophoresis (SDS-PAGE). Moreover, the variation of tensile strength and elongation of dyed samples were determined. In addition, color fastness to domestic laundering, perspiration and rubbing were carried out. Finally, color measurements and fiber section analysis were performed. The results show the possibility, thanks to the pretreatment with the investigated enzyme, to obtain a homogeneous and solid dyeing on fibers maintaining good mechanical properties, already working at 85°C instead of 98°C currently used in industry.
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De Almeida, Aliane C., Victor A. De Araujo, Elen A. M. Morales, Maristela Gava, Rafaele A. Munis, José N. Garcia et Juliana Cortez-Barbosa. « Wood-bamboo particleboard : Mechanical properties ». BioResources 12, no 4 (7 septembre 2017) : 7784–92. http://dx.doi.org/10.15376/biores.12.4.7784-7792.
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Mechanical characteristics were evaluated of wood-bamboo-based particleboard having the proportions of 100% wood and 0% bamboo, 75% wood and 25% bamboo, and 50% wood and 50% bamboo. This particleboard used Eucalyptus urophylla × grandis wood, Dendrocalamus asper bamboo, and castor oil-based polyurethane resin. Through destructive testing, the values of perpendicular tensile, static bending, modulus of elasticity, and screw pullout strength in the top and face surfaces were analyzed. For 0%, 25%, and 50% bamboo the values were 1.68 MPa, 1.37 MPa, and 1.4 MPa, respectively, for perpendicular tensile; 15.2 MPa, 17.6 MPa, and 18.5 MPa, respectively, for static bending; 2466 MPa, 2694 MPa, and 2922 MPa, respectively, for modulus of elasticity; 1256 MPa, 1922 MPa, and 1362 MPa, respectively, for screw pullout strength in top; and 1392 MPa, 1342 MPa, and 1414 MPa, respectively, for screw pullout strength in face. These results were superior to those presented by ABNT NBR 14810 (2013) and ANSI 208.1 (1999). After performing a Tukey test at 5%, the values for each treatment did not show a significant difference among them.
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Namari, Siavash, Lukas Drosky, Bianka Pudlitz, Peer Haller, Adeayo Sotayo, Daniel Bradley, Sameer Mehra et al. « Mechanical properties of compressed wood ». Construction and Building Materials 301 (septembre 2021) : 124269. http://dx.doi.org/10.1016/j.conbuildmat.2021.124269.
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Christoforo, André Luis. « Wood Quality and Mechanical Properties ». Forests 15, no 11 (25 octobre 2024) : 1874. http://dx.doi.org/10.3390/f15111874.
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The recent Special Issue (SI) of Forests on “Wood Quality and Mechanical Properties” offers an in-depth exploration of the complex relationship between the quality of wood and its mechanical properties, in addition to describing innovations in the field [...]
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Abdul majeed, Basma A., et Dhilal Amer Sabar. « Preparations of Organoclay Using Cationic Surfactant and Characterization of PVC/ (Bentonite and Organoclay) Composite Prepared via Melt Blending Method ». Iraqi Journal of Chemical and Petroleum Engineering 18, no 1 (30 mars 2017) : 17–36. http://dx.doi.org/10.31699/ijcpe.2017.1.2.
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Calcium-Montmorillonite (bentonite) [Ca-MMT] has been prepared via cation exchange reaction using benzalkonium chloride [quaternary ammonium] as a surfactant to produce organoclay which is used to prepare polymer composites. Functionalization of this filler surface is very important factor for achieving good interaction between filler and polymer matrix. Basal spacing and functional groups identification of this organoclay were characterized using X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy respectively. The (XRD) results showed that the basal spacing of the treated clay (organoclay) with the benzalkonium chloride increased to 15.17213 0A, this represents an increment of about 77.9% in the basal spacing. FTIR spectra illustrate that benzalkonium chloride compound was successfully intercalated in to clay layers. The results confirm the effectiveness of the synthesis of organoclay with similar characteristics compared to those ones observed in the bentonite. The features were obtained by a simple process and enable interaction with organic compounds (polymers and plastic). PVC/bentonite composite and PVC/organoclay composite were prepared by the melt intercalation method .The results have been analyzed and compared for PVC samples with (3wt%, 7wt% and 12wt %) bentonite and organoclay micro filler .Mechanical properties, thermal properties, flammability and water absorption percentage of prepared samples were tested. Mechanical characteristic such as tensile strength, elongation at break, hardness and impact strength (charpy type) were measured for all samples, where the tensile strength and elongation at break of PVC composites increased with increasing organoclay loading compared with unmodified bentonite. Also, the hardness and impact strength of the composites increase with increase in filler content. Thermal properties of PVC/ (bentonite, organoclay) composites were characterized using Differential Scanning Calorimeter (DSC) and thermal conductivity analyzer. The results showed Tg shifted toward higher temperature for all type of filler compared to neat PVC. Also, thermal conductivity measurement values illustrated that PVC/bentonite composites have a good thermal insulation at 12wt%, thermal conductivity was decreased from 0.222 W/m.K for neat PVC to 0.11 W/m.K at 12wt% PVC/bentonite composites. Organoclay give the best possible water absorbability of the PVC, with other word making it moisture resistant .The higher the filler content the higher burning time, the lower rate of burning and the lower height of the flame which are evident at 12wt% for all fillers.
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Arriaga, Francisco, Xiping Wang, Guillermo Íñiguez-González, Daniel F. Llana, Miguel Esteban et Peter Niemz. « Mechanical Properties of Wood : A Review ». Forests 14, no 6 (9 juin 2023) : 1202. http://dx.doi.org/10.3390/f14061202.
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The use of wood in construction requires knowledge of the mechanical properties and the particularities that wood presents in comparison with other materials used for structural purposes such as steel, concrete, brick, or stone. The introduction mentions the environmental advantages that justify the use of wood today. The orthotropy of wood is one of the differentiating characteristics that must be taken into account when studying its behaviour. The determination of the properties of wood is then addressed from a historical perspective and the differentiation is made between the properties of small clear wood (defect-free timber) and structural timber. The timber grading systems (visual and mechanical grading) and the non-destructive techniques that currently prevail are explained. Finally, the factors that influence the mechanical properties, such as duration of the load, moisture content, quality, temperature, and the effect of size are explained. The objective of this work is to provide an overview of the current knowledge on the mechanical properties of wood, based mainly on published articles and European and North American standards, including historical references to the beginnings and current trends in this field.
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Hussein, Moustafa M., Khaled Nassar et Mohamed Darwish. « Mechanical Properties of Egyptian Casuarina Wood ». Journal of Materials in Civil Engineering 31, no 12 (décembre 2019) : 04019293. http://dx.doi.org/10.1061/(asce)mt.1943-5533.0002955.
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Fitzgerald, Edwin R. « Dynamic mechanical properties of violin wood ». Journal of the Acoustical Society of America 89, no 4B (avril 1991) : 1927. http://dx.doi.org/10.1121/1.2029537.
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Li, Yong Feng, Duo Jun Lv, Chi Jiang, Yi Xing Liu et Hong Yue Zhang. « Fabrication and Mechanical Properties of Wood-PMMA Composite ». Advanced Materials Research 160-162 (novembre 2010) : 640–43. http://dx.doi.org/10.4028/www.scientific.net/amr.160-162.640.
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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 mechanical properties of the composite were tested, and the composite was also analyzed by SEM and DSC to further correlate its performance. The results indicated that the modulus of rupture, modulus of elasticity, compression strength and hardness of Wood-PMMA Composite were improved by 68.28%, 110.27%, 62.43%, 357% over those of Untreated Wood, respectively. The SEM observations showed that PMMA generated and filled up wood pores under the employed conditions, and thus reinforced the mechanical properties of wood. DSC analysis suggested that Wood-PMMA Composite was more thermal stability than Untreated Wood as the formation of PMMA within wood pores.
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Holan, Jiří, et Lukáš Merenda. « Selected mechanical properties of modified beech wood ». Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 56, no 1 (2008) : 245–50. http://dx.doi.org/10.11118/actaun200856010245.
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This thesis deals with an examination of mechanical properties of ammonia treated beach wood with a trademark Lignamon. For determination mechanical properties were used procedures especially based on ČSN. From the results is noticeable increased density of wood by 22% in comparison with untreated beach wood, which makes considerable increase of the most mechanical wood properties. Considering failure strength was raised by 32% and modulus of elasticity was raised at average about 46%.
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Xu, Lin, et Tie Ying Li. « Material Properties Test of Wooden Architecture and its Mechanical Properties ». Advanced Materials Research 788 (septembre 2013) : 651–55. http://dx.doi.org/10.4028/www.scientific.net/amr.788.651.
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Ancient Chinese architecture is the most representative in Chinese ancient civilization. Now preserved ancient ruins are extremely valuable in historical and cultural value, artistic value and scientific value, so the research on the characteristics of ancient building structures in China and its seismic performance have important realistic significance. On the basis of the existing Chinese ancient wooden buildings, the paper discusses the structure performance of Chinese Ancient Timbering Buildings. According to the existing theoretical knowledge, the paper elaborates the reasons for using the wood of Chinese ancient architecture and analyses the basic characteristics of the ancient wood as building materials. We take the experiment of wooden mechanical property test to study the characteristics of material better, and emphasis narrates the whole process of wood bending strength test, then get the results of wood mechanical characteristics.
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Gustafsson, Per Johan. « Modelling of mechanical properties of wood and wood-based materials ». Schweizerische Zeitschrift fur Forstwesen 154, no 12 (1 décembre 2003) : 504–9. http://dx.doi.org/10.3188/szf.2003.0504.
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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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Glukhikh, Viktor, Pavel Buryndin, Artyem Artyemov, Andrei Savinovskih, Pavel Krivonogov et Anna Krivonogova. « Plastics : physical-and-mechanical properties and biodegradable potential ». Foods and Raw Materials 8, no 1 (26 février 2020) : 149–54. http://dx.doi.org/10.21603/2308-4057-2020-1-149-154.
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Introduction. Processing agricultural waste into plant biodegradable plastics is a promising way for its recycling. This work featured the main physical-and-mechanical properties of plant plastics without adhesive substances obtained from millet husk and wheat husk and wood plastic obtained from sawdust, as well as their biodegradation potential.
Study objects and methods. Objects of the study were plastics without adhesives based on wood sawdust, millet husk, and wheat husk.
Results and discussion. We analyzed of the physical-and-mechanical parameters of the plant plastic based on millet husk, wheat husk, as well as wood plastic based on sawdust. The analysis showed that, in general, the strength characteristics of the wood plastics were higher than those of the plastics based on millet husk, especially flexural strength. Thus, the average value of the density of the wood plastic exceeded that of the plant plastic from millet husk by 10%, hardness by 40%, compression elasticity modulus by 50%, and flexural modulus by 3.9 times. It was found that wood and plant plastics obtained from sawdust, millet husk, and wheat husk without adhesives had a high biodegradation potential.
Conclusion. The plastics obtained can be used as an insulating, building, and decorative material in the steppe regions experiencing a shortage of wood and wood powder.