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1
Leblon, Brigitte, Oluwatosin Adedipe, Guillaume Hans, Ataollah Haddadi, Satoru Tsuchikawa, James Burger, Rod Stirling et al. "A review of near-infrared spectroscopy for monitoring moisture content and density of solid wood". Forestry Chronicle 89, n.º 05 (octubre de 2013): 595–606. http://dx.doi.org/10.5558/tfc2013-111.
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This review article examines past and current research on the application of near-infrared (NIR) reflectance/transmittance spectroscopy (NIRS) for real-time monitoring of moisture content and density of solid wood. Most of the applications of NIRS on solid wood have focussed on the application of multivariate statistics as exploratory tools for the prediction of physical, chemical and mechanical properties, such as moisture content, density, stiffness, cellulose and lignin content. However, very few studies on the development of optical models and the use of NIRS transmittance techniques on solid wood have been reported. NIRS technology has the potential to be used as a rapid tool that could be employed for at-line measurement and monitoring of wood properties in the forest products industry.
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MacMillan, Bryce, Emil Veliyulin, Clevan Lamason y Bruce J. Balcom. "Quantitative magnetic resonance measurements of low moisture content wood1This article is a contribution to the series The Role of Sensors in the New Forest Products Industry and Bioeconomy." Canadian Journal of Forest Research 41, n.º 11 (noviembre de 2011): 2158–62. http://dx.doi.org/10.1139/x11-081.
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Magnetic resonance spectroscopy and imaging are well established analytical tools with ever-increasing ranges of application. They are, however, generally underutilized in the areas of forestry and wood science. This is in part due to the complex nature of wood and wood–water interactions and also to the need of wood scientists for quantitative measurements of moisture content, fluid flow, wood structure, etc. Furthermore, magnetic resonance instruments have historically been large, sophisticated, and expensive and not generally compatible with wood production facilities. In this paper, we discuss the limitations of magnetic resonance to applications such as wood and describe how, with recent developments in magnetic resonance imaging technology, these limitations can be overcome. We highlight our own work with quantitative moisture content measurements and outline progress in the development of simpler, lightweight, and mobile magnetic resonance instruments. These are promising devices for routine portable magnetic resonance spectroscopy and imaging, with the potential to finally extend these powerful techniques to the world of foresters and wood scientists.
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Alfredsen, Gry, Christian Brischke, Brendan N. Marais, Robert F. A. Stein, Katrin Zimmer y Miha Humar. "Modelling the Material Resistance of Wood—Part 1: Utilizing Durability Test Data Based on Different Reference Wood Species". Forests 12, n.º 5 (29 de abril de 2021): 558. http://dx.doi.org/10.3390/f12050558.
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To evaluate the performance of new wood-based products, reference wood species with known performances are included in laboratory and field trials. However, different wood species vary in their durability performance, and there will also be a within-species variation. The primary aim of this paper was to compare the material resistance against decay fungi and moisture performance of three European reference wood species, i.e., Scots pine sapwood (Pinus sylvestris), Norway spruce (Picea abies), and European beech (Fagus sylvatica). Wood material was collected from 43 locations all over Europe and exposed to brown rot (Rhodonia placenta), white rot (Trametes versicolor) or soft rot fungi. In addition, five different moisture performance characteristics were analyzed. The main results were the two factors accounting for the wetting ability (kwa) and the inherent protective properties of wood (kinh), factors for conversion between Norway spruce vs. Scots pine sapwood or European beech for the three decay types and four moisture tests, and material resistance dose (DRd) per wood species. The data illustrate that the differences between the three European reference wood species were minor, both with regard to decay and moisture performance. The results also highlight the importance of defined boundaries for density and annual ring width when comparing materials within and between experiments. It was concluded that with the factors obtained, existing, and future test data, where only one or two of the mentioned reference species were used, can be transferred to models and prediction tools that use another of the reference species.
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Dahlen, Joseph, Laurence Schimleck y Erik Schilling. "Modeling and Monitoring of Wood Moisture Content Using Time-Domain Reflectometry". Forests 11, n.º 4 (24 de abril de 2020): 479. http://dx.doi.org/10.3390/f11040479.
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Time-domain reflectometry (TDR) can monitor the moisture content (MC) of water saturated logs stored in wet-decks where the MC exceeds the range that can be measured using traditional moisture meters (>50%). For this application to become routine, it is required that TDR monitoring of wet-decks occurs after establishment, and tools are needed that automate data collection and analysis. We developed models that predict wood MC using three-rod epoxy encased TDR probes inserted into the transverse surface of bolts (prior wet-deck studies were installed on the tangential surface). Models were developed for southern pine, sweetgum, yellow poplar, hickory, red oak, and white oak using a Campbell Scientific TDR100. For each species, at least 37 bolts were soaked for a minimum of three months and then air dried with TDR waveforms, and MC was periodically recorded. Calibrations were developed between MC and the TDR signal using nonlinear mixed effects models. Fixed effects ranged from excellent (southern pine R2 = 0.93) to poor (red oak R2 = 0.36, hickory R2 = 0.38). Independent of wood species, random effects all had a R2 greater than 0.80, which indicates that TDR detects changes in MC at the individual sample level. Use of TDR combined with a datalogger was demonstrated in an operational wet-deck that monitored changes in MC over 12 months, and in a laboratory trial where bolts were exposed to successive wet-dry cycles over 400 days. Both applications demonstrated the utility of TDR to monitor changes in wood MC in high MC environments where periodic measurement is not feasible due to operational safety concerns. Because a saturated TDR reading indicates a saturated MC, and because of the relatively accurate random effects found here, developing individual species models is not necessary for monitoring purposes. Therefore, application of TDR monitoring can be broadly applied for wet-decks, regardless of the species stored.
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Cherry, Marilyn L., Vikas Vikram, David Briggs, Daniel W. Cress y Glenn T. Howe. "Genetic variation in direct and indirect measures of wood stiffness in coastal Douglas-fir". Canadian Journal of Forest Research 38, n.º 9 (septiembre de 2008): 2476–86. http://dx.doi.org/10.1139/x08-087.
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We studied wood stiffness (estimated by modulus of elasticity, MOE), wood density, wood moisture content, and growth in a progeny test (50–130 families per trait; 1–3 sites) of coastal Douglas-fir ( Pseudotsuga menziesii var. menziesii (Mirb.) Franco). We measured MOE directly using lumber bending tests (MOEbl) and indirectly using tools (HM200 and ST300) that can be used to measure acoustic velocity in logs (VelHM) or standing trees (VelST). Acoustic MOEs in logs and standing trees (MOEHM and MOEST) were obtained from the velocities and green wood density. For backward selection, we estimated genetic gains in MOEbl of 8.6%–12.3%. Relative efficiencies (REs), the relative gains in MOEbl expected from indirect selection for correlated traits, were 78%–93% for the HM200 traits, 57%–58% for the ST300 traits, 38% for the basic wood density of basal discs (Denbd), and 98% for the oven-dry density of logs estimated from the lumber (Denol). The HM200 is an efficient tool for improving MOEbl, but gains will be lower using the ST300 on standing trees. Indirect selection on Denbd should be used with caution because the RE was low and Denbd was negatively correlated with growth (–0.49 to –0.73).
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Грибанов, A. Gribanov, Насер, Nikhad Naser, Аббас, Mokhammed Khayder Abbas, Петровский, Vladislav Petrovskiy, Козельчук y D. Kozelchuk. "Mathematical modeling and optimization of milling process control of ornamental pieces of furniture". Forestry Engineering Journal 4, n.º 2 (10 de junio de 2014): 0. http://dx.doi.org/10.12737/4533.
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System analysis of the milling process of furniture parts allowed to allocate target control functions on cleanliness of processing and performance, taking into account the perturbing effects – moisture of wood material. According to the plan of active experiments based on the technical characteristics of existing CNC machine the minimum, maximum, and average values of feed rates and cutting rate of tools are determined. The experiment with 12 pieces of MDF samples allowed determining the mathematical model of the dependence of the objective functions of roughness Ra on the feed rate V, cutting rate of tool w and humidity of the processed material f.
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Sokolowskyi, Yaroslav y Volodymyr Shymanskyi. "Mathematical Modelling of Non-Isothermal Moisture Transfer and Rheological Behavior in Cappilary-Porous Materials with Fractal Structure During Drying". Computer and Information Science 7, n.º 4 (17 de octubre de 2014): 111. http://dx.doi.org/10.5539/cis.v7n4p111.
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The mathematical model of non-isothermal moisture transfer and rheological behavior of wood during drying with taking into account the fractal structure of this material is regarded in the article. The mathematical tools of integration and differentiation of fractional order for description the mathematical model of this process was used. For finding the numerical solution of this problem the finite-difference method predictor-corrector was used. Results show the practicability of using the mathematical tools of integration and differentiation of fractional order to calculate the temperature and humidity fields and the stress-strain state during drying timber.
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McManus, Connie. "Preparing Drosophila for Tissue Processing". Microscopy Today 8, n.º 6 (agosto de 2000): 32–33. http://dx.doi.org/10.1017/s1551929500052810.
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All insects have an exoskeleton made of chitin, which is a protein that is hard and impervious to moisture. To enable processing reagents to more effectively enter the body cavity, a small slit in the abdomen can be made. For very small insects, such as the fruit fly, Drosophila, micro dissecting tools can be made from commonly found items such as insulated electrical wire, double edged razor blades and wood applicator sticks.
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Terziev, Nasko, Geoffrey Daniel y Ann Marklund. "Dislocations in Norway spruce fibres and their effect on properties of pulp and paper". Holzforschung 59, n.º 2 (1 de febrero de 2005): 163–69. http://dx.doi.org/10.1515/hf.2005.025.
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Abstract Wood “cell-wall deformation” is a comprehensive term describing any physical dislocation in the wall caused by mechanical forces. The development and effect of fibre dislocations on wood fibres, and their ultimate impact on the mechanical properties of paper remain rather obscure and controversial. Dislocations are difficult to quantify through a lack of defined measurable features, and research is aggravated by the inherent difficulties of applying statistical tools. A direct approach for studying the effect of dislocations on the mechanical properties of paper was used in this study. Dislocations in fibre cell walls were introduced by exposing whole wood fibres in mature and juvenile wood samples to compression stress. Sapwood samples of Norway spruce (Picea abies Karst.) were loaded by compression to their ultimate strength using an Alwetron-50 universal testing machine. Failure of samples conditioned to a moisture content of 9–15% always occurred in an oblique (relative to the fibre axis) plane and all fibres in the plane were deformed. When samples were loaded in a wet condition (i.e., moisture content close to the fibre saturation point), failure occurred at one end of the samples, resulting in highly disorganised fibres. Pulp and paper from the compressed fibres were produced and the mechanical properties of the paper were tested. Results of the mechanical tests were compared statistically to results derived from paper made from matched non-compressed control samples. Morphological features of fibres and dislocations after compression failure were characterised using microscopy (scanning electron microscopy, polarised light) on the whole wood and macerated fibres before and after paper testing. The above experimental approach showed that paper made from control samples had significantly better mechanical properties than paper made from samples loaded by compression under dry or wet conditions. At a tensile index of 90 N m/g, the tear index was measured as 23.6 mN m2/g for controls, while the corresponding values for compressed wet wood samples was 12.6 and 16.3 mN m2/g for samples at 9–15% moisture content. Paper made from juvenile wood also showed lower mechanical properties compared to controls. The results prove the negative effect of dislocations on the mechanical properties of paper in the worst case scenario and are of practical importance.
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Zanuttini, M., M. Citroni y V. Marzocchi. "Pattern of Alkali Impregnation of Poplar Wood at Moderate Conditions". Holzforschung 54, n.º 6 (25 de octubre de 2000): 631–36. http://dx.doi.org/10.1515/hf.2000.106.
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Summary The impregnation pattern of alkali in fresh Cottonwood is analysed. Isothermal process, medium alkali-concentration, temperature below 100°C and tangential direction are considered. The degree of deacetylation in the wood is taken as an indicator of the whole chemical action of the alkali. Profiles of alkali concentration, alkali content, liquid content and acetyl content in the wood are experimentally determined. The results show that wood behaves rather like a glassy polymeric solid placed in contact with a solvent. An advancing boundary zone is established which separates an intact inner part from the outer swollen zone. Alkali concentration and acetyl groups content profiles can approximately be described by a model used to analyse the reaction of solids: the shrinking core model. The chemical reaction in the front is the controlling mechanism. The swelling of the cell walls together with the occupation of the hollow cavities of the wood by the liquor make it possible for the wood liquid content to increase up to almost 3 g liquid g wood−1. The procedure here adopted and the impregnation pattern proposed are valuable tools to analyse the effect of wood direction and process variables such as temperature, alkali concentration and initial wood moisture. They could also be very useful to build a model for alkaline impregnation of wood under moderate conditions.
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Martin, Benoît, Julien Colin, Pin Lu, Mahamadou Mounkaila, Joel Casalinho, Patrick Perré y Romain Rémond. "Water migration in wood during imbibition assessed by X-ray imaging". E3S Web of Conferences 172 (2020): 14007. http://dx.doi.org/10.1051/e3sconf/202017214007.
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In the wooden construction, structural elements are particularly exposed to external climatic conditions during the construction phase. To ensure their durability over their expected lifespan, the required drying time have to be known after a rain shower and before closing the timber structures. This question, involving coupled heat and mass transfer, can be investigated through numerical tools. The aim of this work is to provide experimental data through X-ray imaging to validate the prediction potential of computational models simulating transfer in porous media. Two complementary methods were developed to access the water migration in Norway spruce. The first one allowed to quantitatively measure spatial distribution of moisture content over time. It is based on a rigorous treatment of the X-ray beam attenuation. The second method, using a high-resolution 3D reconstruction, highlighted the role of wood rays on liquid migration within the porous network.
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Sivonen, Hanne, Mari Nuopponen, Sirkka L. Maunu, Franciska Sundholm y Tapani Vuorinen. "Carbon-Thirteen Cross-Polarization Magic Angle Spinning Nuclear Magnetic Resonance and Fourier Transform Infrared Studies of Thermally Modified Wood Exposed to Brown and Soft Rot Fungi". Applied Spectroscopy 57, n.º 3 (marzo de 2003): 266–73. http://dx.doi.org/10.1366/000370203321558164.
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Thermally modified wood has many technically interesting properties, such as increased dimensional stability, low equilibrium moisture content, and enhanced biological and weather resistance. This paper describes solid-state nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectroscopic studies on the decay of heat-treated and untreated pine ( Pinus sylvestris) by brown ( Poria placenta) and soft rot fungi. Both techniques combined with multivariate data analysis proved to be powerful tools for the study of wood degradation by fungi. When untreated pine was exposed to brown or soft rot fungi, a drastic decay of the cell wall polysaccharides was observed. Brown rot fungus degraded mainly hemicelluloses while soft rot fungus attacked cellulose more extensively. The aromatic region of 13C cross-polarization magic angle spinning (CPMAS) NMR spectra revealed that the structure of lignin was also altered. New carboxylic structures were formed as a consequence of the decay. The increased biological resistance of pine wood heat-treated at >220 °C was observed in the 13C CPMAS NMR and IR spectra.
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Sibilla, Luboš, Milan Vlček, Karel Struhala y Pavel Kříž. "Influence of Orientation of Building on Indoor Conditions in a Roof Truss". Applied Mechanics and Materials 824 (enero de 2016): 267–77. http://dx.doi.org/10.4028/www.scientific.net/amm.824.267.
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Protection of historical roof trusses is an important part of efforts to protect our cultural heritage. These timber structures carry a lot of information about used tools, technologies or construction processes. Roof trusses are generally threatened by many dangers, which could cause irreparable damage and loss of the carried information. Wood destroying insects and fungi are the gravest threat to historical roof trusses in our climatic conditions. Their spreading depends on several specific (interior) conditions. These include critical moisture content in the wood, relative humidity, amount of natural light and ventilation. In addition to these commonly monitored parameters (and their critical levels) we also must not forget the influence of local geography, biotope or orientation to the cardinal. This paper describes temporal fluctuations of some of the mentioned physical parameters in a historical roof truss with regard to external climatic conditions and orientation to the cardinal.
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Sibilla, Luboš, Milan Vlček, Karel Struhala y Pavel Kříž. "Evaluation of the Dependence of the Parameters of Internal Environment of Wooden Truss on the Orientation of the Building". Applied Mechanics and Materials 861 (diciembre de 2016): 287–94. http://dx.doi.org/10.4028/www.scientific.net/amm.861.287.
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Historical wooden trusses carry a lot of information about used tools, technologies or construction processes. Unfortunately they are generally threatened by many dangers, which could cause irreparable damage and loss of the carried information. Protection of historical roof trusses is an important part of efforts to protect our cultural heritage. Wood destroying insects and fungi are the most serious threats to historical roof trusses in our climatic conditions. Their spreading depends on several specific (interior) conditions. These include critical moisture content in the wood, relative humidity, temperature, etc. In addition to these commonly monitored parameters (and their critical levels) we also must not forget the influence of local geography, biotope or orientation to the cardinal. This paper describes temporal fluctuations of some of the mentioned physical parameters in a historical roof truss (in Brno, Czech Republic) with regard to external climatic conditions and orientation to the cardinal.
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Stanciu, Mariana Domnica, Ioan Curtu y Daniel Mihalache. "Design of Experimental Test Bench for Determining the Stresses and Strains State of Guitar Neck". Applied Mechanics and Materials 658 (octubre de 2014): 219–24. http://dx.doi.org/10.4028/www.scientific.net/amm.658.219.
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Bending causes of neck guitar, with negative economic effects are: technology - deviations from flatness, straightness, produced during processes due to faulty adjustment of machine tools, structure / material – the wood used in guitar structure leads to deformations that exceed the terms of rigidity due to anisotropy, mechanical - occurrence rheological phenomena (wood relaxation after being subjected to stresses during machining), physical - wood moisture, humidity and ambient temperature. Bending of guitar neck occurs either after completion of manufacturing processes when the guitar is not used (case I), or after a storage period without it being stressed (case II) and after a period of use (case III). The paper presents the concept of experimental stand and a set of procedures for measuring deformations of guitar neck obtained during the bending stress in three points (Figure 1). The criteria in the design of test bench were: providing mechanical boundary conditions to simulate real conditions; ensuring mobility measuring apparatus and data recording so that it can be investigated all the structural elements of the guitar; ensure stability of the tabs and the whole stand in order to avoid measurement errors; ensure handling and maintenance of subassemblies by using ergonomic dimensions, optimum materials and interchangeable parts.
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Mora, Christian R., Laurence R. Schimleck, Fikret Isik, Jerry M. Mahon, Alexander Clark y Richard F. Daniels. "Relationships between acoustic variables and different measures of stiffness in standing Pinus taeda trees". Canadian Journal of Forest Research 39, n.º 8 (agosto de 2009): 1421–29. http://dx.doi.org/10.1139/x09-062.
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Acoustic tools are increasingly used to estimate standing-tree (dynamic) stiffness; however, such techniques overestimate static stiffness, the standard measurement for determining modulus of elasticity (MOE) of wood. This study aimed to identify correction methods for standing-tree estimates making dynamic and static stiffness comparable. Sixty Pinus taeda L. trees, ranging from 14 to 19 years old, obtained from genetic tests established in the southeastern United States, were analyzed. Standing-tree acoustic velocities were measured using the TreeSonic tool. Acoustic velocities were also recorded in butt logs cut from the same trees using the Director HM200. A strong but biased relationship between tree and log velocities was observed, with tree velocities 32% higher (on average) than the corresponding log velocities. Two correction methods, one for calibrating tree velocities and one for accounting for differences in wood moisture content, were used to determine an adjusted MOE. After correction, adjusted MOE estimates were in good agreement with static longitudinal MOE values measured on clearwood specimens obtained from the trees, and no systematic bias was observed. The results of this study show that acoustic estimates of MOE on standing trees largely depend on how the data are processed and the reference method used.
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Choidis, Petros, Katerina Tsikaloudaki y Dimitrios Kraniotis. "Hygrothermal performance of log walls in a building of 18th century and prediction of climate change impact on biological deterioration". E3S Web of Conferences 172 (2020): 15006. http://dx.doi.org/10.1051/e3sconf/202017215006.
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Several studies underline the dramatic changes that are expected to take place in nature and environment due to climate change. The latter is also expected to affect the built environment. Particular emphasis is currently given to the impact of climate change on historical structures. Within this context, it is important to use simple methods and novel tools in order to investigate specific case studies. In this study, the climate change impact on the hygrothermal performance of the log walls in a historic timber building is presented. The building under investigation is the Fadum storehouse, also known as ‘the coated house’, located in Tønsberg, Norway. The storehouse dates to the late 18th century. It has a particular design with the main features of stumps or piles up to which it stands and the ‘coating’ that covers its outer walls. The main damage of the construction is related to the biological degradation of the wood. The hygrothermal performance of the log walls, as well as the exterior and interior climate, have been monitored and the results have been used to validate a Heat, Air and Moisture transport (HAM) model. The validated HAM model is then used to examine the performance of the log walls for both current and potential future climate conditions. The transient hygrothermal boundary conditions serve as the input parameters to a biohygrothermal model that is used to investigate the biological deterioration of the building components. The findings reveal that currently there is no mould risk for the main body of the construction, which is in accordance with the visual inspection. The passive systems of the building are highly conducive to these results, since they protect it from driving rain and other sources of moisture and eliminate the potential impact of future climate change risk scenarios.
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Martín-Garín, Alexander, José Antonio Millán-García, Jon Terés-Zubiaga, Xabat Oregi, Iñigo Rodríguez-Vidal y Abderrahmane Baïri. "Improving Energy Performance of Historic Buildings through Hygrothermal Assessment of the Envelope". Buildings 11, n.º 9 (15 de septiembre de 2021): 410. http://dx.doi.org/10.3390/buildings11090410.
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The intervention on historic buildings through building energy retrofitting has become one of the current challenges of improving energy efficiency. Nonetheless, this building typology presents certain complexities. Among them, one of the most relevant is the protection on their façades due to the historical and/or artistic values of a given façade and, therefore, the addition of external thermal insulation is restricted. However, at the same time, in several of those buildings indoor surfaces do not present that architectural value, and then internal thermal insulation becomes a promising strategy for improving their thermal performance. Nevertheless, its application must be carefully evaluated to avoid possible pathologies caused by moisture problems. This paper aims to identify constructive solutions for interior insulation of walls free from moisture problems. For this purpose, a comprehensive analysis of a series of constructive solutions based on internal insulation has been carried out through hygrothermal simulations. The results show how the application of water-repellent impregnation becomes essential to guaranteeing the integrity of the envelope. In addition, the combination of insulations with or without inner membranes, such as smart vapor retarders or vapor diffusion barriers, has been evaluated detecting the solutions that best fit the objective. Finally, taking advantage of the great potential of 2D simulation tools, the post-processing of the data has been performed to apply the wood decay model, and thus assess the behavior of a very conflictive point in this type of intervention, i.e., the wooden beam-ends. The results in this critical point have shown how the application of the proposed constructive solutions becomes essential to guarantee the integrity of the element and how the application of traditional solutions could lead to a hazard that must be avoided.
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Thybring, Emil Engelund y Maria Fredriksson. "Wood Modification as a Tool to Understand Moisture in Wood". Forests 12, n.º 3 (20 de marzo de 2021): 372. http://dx.doi.org/10.3390/f12030372.
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Moisture plays a central role in the performance of wood products because it affects important material properties such as the resistance to decomposition, the mechanical properties, and the dimensions. To improve wood performance, a wide range of wood modification techniques that alter the wood chemistry in various ways have been described in the literature. Typically, these modifications aim to improve resistance to decomposition, dimensional stability, or, to introduce novel functionalities in the wood. However, wood modification techniques can also be an important tool to improve our understanding of the interactions between wood and moisture. In this review, we describe current knowledge gaps in our understanding of moisture in wood and how modification has been and could be used to clarify some of these gaps. This review shows that introducing specific chemical changes, and even controlling the distribution of these, in combination with the variety of experimental methods available for characterization of moisture in wood, could give novel insights into the interaction between moisture and wood. Such insights could further contribute to applications in several related fields of research such as how to enhance the resistance to decomposition, how to improve the performance of moisture-induced wooden actuators, or how to improve the utilization of wood biomass with challenging swelling anisotropy.
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Zanuncio, Antônio José Vinha, Amélia Guimarães Carvalho, Liniker Fernandes da Silva, Angélica de Cássia Oliveira Carneiro y Jorge Luiz Colodette. "ARTIFICIAL NEURAL NETWORKS AS A NEW TOOL FOR ASSESSING AND MONITORING WOOD MOISTURE CONTENT". Revista Árvore 40, n.º 3 (junio de 2016): 543–49. http://dx.doi.org/10.1590/0100-67622016000300018.
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ABSTRACT Drying of wood is necessary for its use and moisture control is important during this process. The aim of this study was to use artificial neural networks to evaluate and monitor the wood moisture content during drying. Wood samples of 2 × 2 × 4 cm were taken at 1.3 m above the ground, outside of radial direction, from seven 2-year-old materials and three 7-year-old materials. These samples were saturated and drying was evaluated until the equilibrium moisture content, then, the artificial neural networks were created. The materials with higher initial moisture reached equilibrium moisture content faster due to its higher drying rate. The basic density of all wood materials was inversely proportional at the beginning and directly proportional to the moisture at the end of drying. All artificial neural networks used in this work showed high accuracy to estimate the moisture, however, the neural network based on the basic density and drying days was the best. Therefore, artificial neural networks can be used to control the moisture content of wood during drying.
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Lev, Jakub, Václav Křepčík, Egidijus Šarauskis y František Kumhála. "Electrical Capacitance Characteristics of Wood Chips at Low Frequency Ranges: A Cheap Tool for Quality Assessment". Sensors 21, n.º 10 (17 de mayo de 2021): 3494. http://dx.doi.org/10.3390/s21103494.
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Moisture content is one of the most important parameters related to the quality of wood chips that affects both the calorific and economic value of fuel chips. For industrial applications, moisture content needs to be detected quickly. For this purpose, various indirect moisture content measurement methods (e.g., capacitance, NIR, microwave, ECT, X-ray CT, and nuclear MR) have been investigated with different results in the past. Nevertheless, determining wood chip moisture content in real time is still a challenge. The main aim of this article was therefore to analyze the dielectric properties of wood chips at low frequencies (10 kHz–5 MHz) and to examine the possibility of using these properties to predict wood chip moisture content and porosity. A container-type probe was developed for this purpose. The electrical capacitance and dissipation factor of wood chips with different moisture content was measured by an LCR meter at 10 kHz, 50 kHz, 100 kHz, 500 kHz, 1 MHz, and 5 MHz frequencies. Wood chip porosity was also measured using a gas displacement method. Linear models for moisture content and porosity prediction were determined by backward stepwise linear regression. Mathematical model was developed to better understand the physical relationships between moisture content, porosity, and electrical capacitance. These models were able to predict the moisture content of observed quantities of wood chips with the required accuracy (R2 = 0.9–0.99). This finding opens another path to measuring the moisture content and porosity of wood chips in a relatively cheap and fast way and with adequate precision. In addition, principal component analysis showed that it is also possible to distinguish between individual wood chip fraction sizes from the information obtained.
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Digaitis, Ramūnas, Emil E. Thybring, Lisbeth G. Thygesen y Maria Fredriksson. "Targeted acetylation of wood: a tool for tuning wood-water interactions". Cellulose 28, n.º 12 (27 de junio de 2021): 8009–25. http://dx.doi.org/10.1007/s10570-021-04033-z.
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Abstract Wood is an increasingly important material in the sustainable transition of societies worldwide. The performance of wood in structures is intimately tied to the presence of moisture in the material, which directly affects important characteristics such as dimensions and mechanical properties, and indirectly its susceptibility to fungal decomposition. By chemical modification, the durability of wood in outdoor environments can be improved by reducing the amount of moisture present. In this study, we refined a well-known chemical modification with acetic anhydride and showed how the spatial distribution of the modification of Norway spruce (Picea abies (L.) Karst.) could be controlled with the aim of altering the wood-water interactions differently in different parts of the wood structure. By controlling the reaction conditions of the acetylation it was possible to acetylate only the cell wall-lumen interface, or uniformly modify the whole cell wall to different degrees. The spatial distribution of the acetylation was visualised by confocal Raman microspectroscopy. The results showed that by this targeted acetylation procedure it was possible to independently alter the wood-water interactions in and outside of cell walls. The cell wall-lumen interface modification altered the interaction between the wood and the water in cell lumina without affecting the interaction with water in cell walls while the uniform modification affected both. This opens up a novel path for studying wood-water interactions in very moist environments and how moisture distribution within the wood affects its susceptibility towards fungal decomposition. Graphic abstract
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Way, Daniel, Frederick A. Kamke y Arijit Sinha. "Moisture Transport in Wood-Based Structural Panels under Transient Hygroscopic Conditions". Forest Products Journal 70, n.º 3 (1 de enero de 2020): 283–92. http://dx.doi.org/10.13073/fpj-d-20-00012.
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Abstract Development of moisture gradients within wood and wood-based composites can result in irreversible moisture-induced damage. Accelerated weathering (AW), generally employing harsh environmental conditions, is a common tool for assessing moisture durability of wood composite products. Use of milder AW conditions, such as cyclic changes in relative humidity (RH), may be of interest to the wood-based composites industry in assessing moisture durability under more realistic conditions. The primary objective of this study was to determine whether moisture profile development in oriented strand board and plywood during cyclic RH changes could be reasonably predicted with a simple moisture transport model, which may be practical for wood-based composite industry members seeking to develop new AW protocols. The diffusion model based on Fick's second law with empirically determined moisture transport parameters fits the experimental data reasonably well for the purpose of screening RH parameters.
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Rimár, Miroslav y Štefan Kuna. "Design of Methodology for Wood Chips Moisture Evaluation". Applied Mechanics and Materials 308 (febrero de 2013): 141–46. http://dx.doi.org/10.4028/www.scientific.net/amm.308.141.
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Moisture is an important factor of evaluating of burning process efficiency. Unfavorable moisture increases the requirements for energy/fuel consumption which is needed to evaporate water and in a negative manner affects the volume of exhaust gas, the amount of water vapor in exhaust gas as well as the increase in the temperature of the exhaust gas dew point. Thus, wood chips moisture monitoring is a diagnostics tool suitable for the evaluation of operating parameters and a combustion process. The article deals with the design of an appropriate method of measurement and evaluation of wood chips moisture and compares two methods of moisture determining. The problem of moisture determining consists mainly in selecting a suitable method according to the estimation of content of water in wood chips. Another factor to be considered is the fact that moisture in wood chips due to the ambient conditions (temperature, pressure, humidity) changes over time.
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Rodrigues, Brunela Pollastrelli, Christopher Adam Senalik, Xi Wu y James Wacker. "Use of Ground Penetrating Radar in the Evaluation of Wood Structures: A Review". Forests 12, n.º 4 (16 de abril de 2021): 492. http://dx.doi.org/10.3390/f12040492.
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This paper is a review of published studies involving the use of ground penetrating radar (GPR) on wood structures. It also contains background information to help the reader understand how GPR functions. The use of GPR on wood structures began to grow in popularity at the turn of the millennium. GPR has many characteristics that make it attractive as an inspection tool for wood: it is faster than many acoustic and stress wave techniques; it does not require the use of a couplant; while it can also detect the presence of moisture. Moisture detection is of prime concern, and several researchers have labored to measure internal moisture using GPR. While there have been several laboratory studies involving the use of GPR on wood, its use as an inspection tool on large wood structures has been limited. This review identified knowledge gaps that need to be addressed to improve the efficacy of GPR as a reliable inspection tool of wood structure. Chief among these gaps, is the ability to distinguish the type of internal feature from the GPR output and the ability to identify internal decay.
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Zanuncio, Antonio Jose Vinha, Amelia Guimaraes Carvalho, Marcela Gomes da Silva y José Tarcisio Lima. "IMPORTANCE OF WOOD DRYING TO THE FOREST TRANSPORT AND PULP MILL SUPPLY". CERNE 23, n.º 2 (junio de 2017): 147–52. http://dx.doi.org/10.1590/01047760201723022223.
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ABSTRACT The forest transportation represents a great proportion of raw material cost for pulp and paper production and, for this reason, the wood moisture content should be low to reduce these cost. The objective was to relate the wood moisture with fuel consumption per kilometer in each vehicle and the number of trips to supply a pulp mill. Three trees of Eucalyptus urophylla clone and three of Corymbia citriodora from seeds were used. These trees were felled and their logs removed from its base and at 50 and 100% of the commercial height. The basic density and initial moisture of wood were determined and the air drying monitored during 90 days. The fuel consumption to transport one ton of dry wood and the number of trips required to supply a pulp mill were estimated based on the number of air drying days. Air drying reduced the fuel consumption and the number of trips to supply the pulp mill. The accuracy of models to estimate the wood moisture, fuel consumption and the number of trips based in days of drying was high. Therefore, wood drying is an essential tool to reduce forest transport costs.
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Perré, Patrick. "Experimental device for the accurate determination of wood-water relations on micro-samples". Holzforschung 61, n.º 4 (1 de junio de 2007): 419–29. http://dx.doi.org/10.1515/hf.2007.075.
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Abstract This paper describes an experimental device designed for the accurate determination of wood/water relations on micro-samples. The moisture content of the sample is measured with a highly sensitive electronic microbalance. Moreover, the dimensions of the sample in tangential and longitudinal direction are collected continuously without contact by means of two high-speed laser scan micrometers. The device is placed in a climatic chamber. The micro-samples investigated were prepared with a diamond wire saw. A sample thickness of less than 1 mm allows the moisture content to be almost uniform during the test. The data obtained are of excellent quality and accuracy, in spite of the very small mass and dimensions of the samples. The device provides a perfect tool for investigating the dynamic interaction between relative humidity, moisture content, and shrinkage. Results collected for beech, spruce and eucalyptus are presented. Important findings include: deviation from a linear relation between shrinkage and moisture content in beech; uniqueness of the shrinkage versus moisture content curve during desorption/adsorption cycles; evidence of cell collapse in eucalyptus, especially for tension wood; and property variations within the growth ring of normal wood and compression wood of spruce.
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Rosner, Sabine, Martin Riegler, Peter Vontobel, David Mannes, Eberhard H. Lehmann, Bo Karlsson y Christian Hansmann. "Within-ring movement of free water in dehydrating Norway spruce sapwood visualized by neutron radiography". Holzforschung 66, n.º 6 (1 de agosto de 2012): 751–56. http://dx.doi.org/10.1515/hf-2011-0234.
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Abstract This study is a first approach to visualize moisture distribution and movement between annual rings during sapwood drying by neutron imaging (NI). While Norway spruce [Picea abies (L.) Karst.] sapwood beams were allowed to dehydrate on a balance at ambient conditions, NI was performed in 1–10 min time steps. From NI raw files, radial dimensional changes were calculated during dehydration and transmission profiles were drawn for different relative moisture content (MC) steps from full saturation until equilibrium moisture content. The NI technique proved to be a useful tool to visualize the movement of free water within, and between, annual rings. Removal of free water in the middle part of the wood beam did not proceed continuously from the surface to the central part, but was strongly influenced by wood anatomy. Water is removed from earlywood during early stages of dehydration and later, at higher moisture loss (<50% MC), from the main latewood parts. It is therefore concluded that the radial dimensional changes measured at moderate moisture loss are not only caused by cell wall shrinkage of the outer wood parts located beneath the wood surface, but a result of elastic deformation of earlywood tracheids under the influence of negative hydrostatic pressures.
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Florisson, Sara, Johan Vessby, Winston Mmari y Sigurdur Ormarsson. "Three-dimensional orthotropic nonlinear transient moisture simulation for wood: analysis on the effect of scanning curves and nonlinearity". Wood Science and Technology 54, n.º 5 (14 de agosto de 2020): 1197–222. http://dx.doi.org/10.1007/s00226-020-01210-4.
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Abstract This paper introduces, with the development of user-subroutines in the finite-element software Abaqus FEA®, a new practical analysis tool to simulate transient nonlinear moisture transport in wood. The tool is used to revisit the calibration of moisture simulations prior to the simulation of mechanical behaviour in bending subjected to climate change. Often, this calibration does not receive sufficient attention, since the properties and mechanical behaviour are strongly moisture dependent. The calibration of the moisture transport simulation is made with the average volumetric mass data experimentally obtained on a paired specimen of Norway spruce (Picea abies) with the dimensions $$30\times 15\times 640\, {\mathrm{mm}}^{3}$$ 30 × 15 × 640 mm 3 . The data, from a 90-day period, were measured under a constant temperature of 60 °C and systematic relative humidity cycles between 40 and 80%. A practical method based on analytical expressions was used to incorporate hysteresis and scanning behaviour at the boundary surface. The simulation tool makes the single-Fickian model and Neumann boundary condition readily available and the simulations more flexible to different uses. It also allows for a smoother description of inhomogeneity of material. The analysis from the calibration showed that scanning curves associated with hysteresis cannot be neglected in the simulation. The nonlinearity of the analysis indicated that a coherent set of moisture dependent diffusion and surface emission coefficient is necessary for the correct description of moisture gradients and mass transport.
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Milic, Goran y Nebojsa Todorovic. "Analysis of mechano-sorptive effect in oscillatory drying of beech timber". Bulletin of the Faculty of Forestry, n.º 114 (2016): 119–36. http://dx.doi.org/10.2298/gsf1614119m.
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The paper shows results of analysis of influences of oscillating parameters of drying on measuring wood moisture content in the kiln, rate and quality of drying. For this analysis, we used a conventional drying cycle, a cycle with oscillating equilibrium moisture content (EMC), and a cycle with oscillating temperatures. A special software tool was created for managing the oscillations. It was shown that oscillations of EMC and temperatures result in cyclic changes in wood MC, but also in the additional inaccuracies of MC measurements in the kiln. The drying process of the cycle with oscillating EMC lasted somewhat shorter than the other two cycles. Drying quality was the same or better in the cycles with oscillations as compared to the conventionally dried cycle, and the smaller tensions in the wood confirmed the activation of the additional mechano-sorptive effect during cyclic changes of MC in surface layers.
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VELÁZQUEZ-MARTÍ, B. y C. CAZCO-LOGROÑO. "STRUCTURE ANALYSIS AND BIOMASS MODELS FOR PLUM TREE (PRUNUS DOMESTICA L.) IN ECUADOR". Experimental Agriculture 54, n.º 1 (25 de enero de 2017): 133–41. http://dx.doi.org/10.1017/s001447971600079x.
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SUMMARYThe development of dendrometric methodologies could allow accurate estimation of variables associated with the crown, such as primary production (fruit and timber) and tree vigor. The aim of this work was to develop a suitable method to estimate woody biomass in plum trees (Prunus domestica L.) in Imbabura, Ecuador by using an adapted dendrometry. Form factors and regression models were defined for branch volume calculation. From this, the distribution of woody biomass in the crown tree was characterized in every stratum. Occupation Factor and regression models were obtained in order to calculate the biomass in the crown tree, which can be used to estimate the CO2 captured in its structure during its development. Regression models for calculation of whole volume of the tree and pruned biomass were directly obtained from crown diameter and crown height with Rajustated2 of 0.74 and 0.81. The average moisture content of green material was 51%, and the average density of dry material was 0.66 ± 0.07 g cm−3. Proximate analysis of plum wood showed at 79.8 ± 9.2% volatiles and 2.1 ± 0.3% ash. Elemental analysis of the wood pointed to 46.5 ± 1.2% C, 6.1 ± 0.5% H, 46.3 ± 1.2% O, 0.6 ± 0.3% N, 0.06 ± 0.02% S and 0.02 ± 0.01% Cl. Cl, S and N contents are lower than the limits established by the standard EN 14691-part 4. With 46% of C, considering the relation 3.67 (44/12) between CO2 and C content, the CO2 sequestrated in the materials is 1.11 Mg m−3 wood material. Such method represents a tool to manage orchard resources and for assessing other parameters, such as raw materials for cultivation, fruit production, CO2 sink and waste materials (residual wood) used for energy or industry.
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Mikac, Urša, Maks Merela, Primož Oven, Ana Sepe y Igor Serša. "MR Study of Water Distribution in a Beech (Fagus sylvatica) Branch Using Relaxometry Methods". Molecules 26, n.º 14 (16 de julio de 2021): 4305. http://dx.doi.org/10.3390/molecules26144305.
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Wood is a widely used material because it is environmentally sustainable, renewable and relatively inexpensive. Due to the hygroscopic nature of wood, its physical and mechanical properties as well as the susceptibility to fungal decay are strongly influenced by its moisture content, constantly changing in the course of everyday use. Therefore, the understanding of the water state (free or bound) and its distribution at different moisture contents is of great importance. In this study, changes of the water state and its distribution in a beech sample while drying from the green (fresh cut) to the absolutely dry state were monitored by 1D and 2D 1H NMR relaxometry as well as by spatial mapping of the relaxation times T1 and T2. The relaxometry results are consistent with the model of homogeneously emptying pores in the bioporous system with connected pores. This was also confirmed by the relaxation time mapping results which revealed the moisture transport in the course of drying from an axially oriented early- and latewood system to radial rays through which it evaporates from the branch. The results of this study confirmed that MRI is an efficient tool to study the pathways of water transport in wood in the course of drying and is capable of determining the state of water and its distribution in wood.
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Tiwana, K., P. Mukhopadhyaya, E. Zalok, D. Van Reenen, C. Copeland y P. Newman. "Moisture management performance of wood-frame in-fill wall in Shanghai, China". International Review of Applied Sciences and Engineering 6, n.º 2 (diciembre de 2015): 111–27. http://dx.doi.org/10.1556/1848.2015.6.2.5.
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This paper discusses the results of a research project which aimed at determining the hygrothermal (i.e. thermal and moisture) performance of the Canadian wood-frame building envelope construction in the city of Shanghai in China. The performance assessments of the wood-frame walls were conducted using the two-dimensional hygrothermal simulation tool called hygIRC-2D. In this study an in-fill type wall was considered and hygrothermal simulations were carried out for the weather conditions of Shanghai. Investigations were conducted to determine the influence of the vapour barrier, exterior stucco cladding material and different types of sheathing boards on the moisture performance of in-fill walls. Additional simulations were carried out to determine the influence of air leakage on the moisture performance of in-fill walls. The outputs from the simulations were analysed with the help of a hygrothermal response indicator called RHT index. It was concluded that the design of the in-fill wall including a rain screen but omitting a vapour barrier is expected to lead to the maximum reduction in hygrothermal loading when exposed to the weather conditions of Shanghai, China.
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Wang, Wang, Yuan Zhu, Jinzhen Cao y Pascal D. Kamdem. "Monitoring electrical properties of thermally modified wood as a possible tool for quality assessment". Holzforschung 70, n.º 4 (1 de abril de 2016): 351–59. http://dx.doi.org/10.1515/hf-2014-0366.
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Abstract The electrical properties of thermally modified wood (TMW) of southern pine (Pinus spp.) have been investigated, while the samples were modified at 150°C, 175°C, 200°C, and 225°C for 4 h. After conditioning the samples at five relative humidities, the constants for electrical resistance (kR) and dielectricity (kP) were measured and calculated according to the model “electrical properties vs. moisture content”. The correlations between kR and kP and mass loss (ML), CIEL*a*b* color and bending properties in terms of modulus of rupture and modulus of elasticity were established. The coefficients of determination (R2) between these parameters were found to be between 0.926 and 0.999. TM influenced both kR and kP via changing the concentration and mobility of ions inside the wood and decreasing amount of polar groups of wood polymers. The conclusion is that the severity of TM such as the mechanical properties of TMW is in a close relation to the electrical properties.
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Ma, Da Yan, Xi Ming Wang, Ming Hui Zhang y Xue Qi Li. "Quantitative Separation of NMR Signal Amplitude of Water in Wood on the Basis of T2". Materials Science Forum 704-705 (diciembre de 2011): 552–57. http://dx.doi.org/10.4028/www.scientific.net/msf.704-705.552.
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As a kind of crude and green material, wood is essential to human life. Meanwhile, the amount of water played a vital role to almost all engineering properties of wood. Moisture affects dimensional stability, physical and mechanical properties, and susceptibility toward biological degradation. Consequently, it provides a theoretical basis for the reasonable drying model to explore the water assignment and content in timber. we present here the application of a nuclear magnetic resonance technique, which is used to quantitatively analyse water distribution in wood on the basis of T2. In this paper, we will analyse the water distribution in hardwood on the basis of T2. Refer to the scanning electron micrographs of the hardwood, we can speculate the relaxation time of the water in different cell lumens respectively. Moreover, it is even more important to calculate the organic proportion in wood by the corresponding amplitude of signal derived from the water in different cell lumens. This, compared with a scanning electron micrograph, has allowed us to produce a assumable distribution of water in wood, even the corresponding organic proportion in wood, which allows us to speculate physical and mechanical properties of wood. A mobile NMR probe has been used as a non-destructive and non-invasive tool for water content analysis on wood samples. In this paper, we will adopt NMR methods to explain. This, has opened up a way for the accurate determination of the moisture content of wood, even can be applied to the areas of food and so on. Keywords: Nuclear magnetic resonance; Water distribution in wood; T2; Scanning electron micrograph; Water content
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Pearson, Hamish, Sigurdur Ormarsson y Brian Gabbitas. "Nonlinear tensile creep behavior of radiata pine at elevated temperatures and different moisture contents". Holzforschung 69, n.º 7 (1 de septiembre de 2015): 915–23. http://dx.doi.org/10.1515/hf-2014-0240.
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Abstract Tensile wood creep has not been measured previously in the temperature region 135°C–150°C for a range of moisture content (MC) up to fiber saturation point due to equipment and measurement challenges. Yet this is the region where the most dramatic softening effects can be observed. The aim of this study was to develop specialized equipment to measure tensile solid wood creep over 70°C–150°C for a range of MC and loads. Creep displacement was successfully able to be isolated from elastic and mechanosorptive strains and statistically modeled by regression analysis. This proved more accurate than complex series expansions consisting of spring- and dashpot-type components. The best creep displacement relationship was a power law with a strain root mean square error of 0.28%. The amplitude of the power law was nonlinear with respect to stress and temperature and changed by a stress factor of up to 0.9 for a stress of up to 1.2 MPa and by a temperature factor 1.2–6.3 over the investigated range. The creep relationship provides a valuable tool for predicting time-dependent distortion and internal stress of wood during drying or thermohygromechanical modification below 150°C.
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Steidl, E., L. Sobczak y C. Pretschuh. "Monitoring of Injection Molding Tool Corrosion and Effects of Wood Plastic Compound's Moisture on Material Properties". International Polymer Processing 33, n.º 1 (2 de marzo de 2018): 66–75. http://dx.doi.org/10.3139/217.3382.
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Yrjölä, Jukka. "Production of dry wood chips in connection with a district heating plant". Thermal Science 8, n.º 2 (2004): 143–55. http://dx.doi.org/10.2298/tsci0402143y.
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Moisture and its variation in wood chips make the control of burning in small scale heating appliances difficult resulting in emissions and loss of efficiency. If the quality of wood chips would be better, i. e. dried and sieved fuel with more uniform size distribution would be avail able, the burning could be much cleaner and efficiency higher. In addition higher power out put could be obtained and the investment costs of the burning appliances would be lower. The production of sieved and dried wood chip with good quality could be accomplished in connection with a district heating plant. Then the plant would make profit, in addition to the district heat, from the dried wood chips sold to the neighboring buildings and enterprises sep a rated from the district heating net using wood chips in energy production. The peak power of a district heating plant is required only a short time during the coldest days of the winter. Then the excess capacity during the milder days can be used as heat source for drying of wood chips to be marketed. Then wood chips are sieved and the fuel with best quality is sold and the reject is used as fuel in the plant it self. In a larger district heating plant, quality of the fuel does not need to be so high In this paper the effect of moisture on the fuel chain and on the boiler is discussed. Energy and mass balance calculations as a tool of system design is described and the characteristics of proposed dry chips production method is discussed.
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Reichel, Vicky, Werner Berlin, Felix Rothe, Jan Beuscher y Klaus Dröder. "Study of Shear-Cutting Mechanisms on Wood Veneer". Forests 11, n.º 6 (24 de junio de 2020): 703. http://dx.doi.org/10.3390/f11060703.
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Multi-material structures made from renewable materials are increasingly being addressed in research and industry. Especially lightweight applications based on wood and polymer materials offer an important opportunity to reduce weight and CO2 emissions, and thus create a sustainable economy. When establishing new material combinations, it is necessary to take economical and efficient manufacturing processes into count to enable the market entry. Therefore, the existing manufacturing processes needed to be adapted and improved in terms of the specific machining characteristic of the wood material. This study targets a combined process where a forming and shear-cutting process is also integrated in an injection-molding tool. The findings on the shear-cutting process of wood veneers are not widely investigated yet. Therefore, process and material-related dependences like cutting velocity, tool shape design, and preconditioning of wood veneers were examined. The target values cutting force and cutting-edge quality were used to describe the relations. The results showed specific damage and fiber fractions of the wood material compared to the isotropic materials (e.g., metal). In addition, low cutting forces appeared by realizing a drawing cut and high cutting speeds. A decrease in the cutting force with a higher moisture content could not be shown for the used wood types.
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SÁNCHEZ GATÓN, MIGUEL ÁNGEL, MARIA ISABEL CAMPOS LABADIE y JOSE JUAN SEGOVIA PURAS. "PREDICTION FOR TOTAL MOISTURE CONTENT IN WOOD PELLETS BY NEAR INFRARED SPECTROSCOPY (NIRS)". DYNA 96, n.º 3 (1 de mayo de 2021): 296–301. http://dx.doi.org/10.6036/9935.
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Mankind consumes as many fossil fuels per year as nature produced during a million years. Furthermore, energy consumption has tripled in the last 60 years, and is expected to be doubled in 2050, due to the technological and economic takeoff of large emerging powers. In light of this scenario, a change in energy policies should be aimed to promote energy efficiency and the use of sustainable energy resources, such as bioenergy, safely and environmental friendly. Biomass fuels take a main role in the EU's energy and climate policies, aimed at reducing CO2 emissions and combating Climate Change. Quality control of biofuels and knowledge of their characteristics reach a large relevance in any industrial application based on the energy use of biofuels. NIRS technology (near infrared spectroscopy, Near Infrared Reflectance Spectroscopy) is based on the interaction between electromagnetic radiation and material, and now is presented as an encouraging technological tool for quality testing of solid biofuels, since it is a non-destructive and much faster and cheaper analytical technique than traditional ones, which are based on current ISO standards. That interaction appears as spectral vibrations (energy absorption or absorbance) that are properly processed, allowing to measure the most important physical-chemical properties of solid biofuels in a fast, simple and non-destructive way. Wood pellet is the highest quality solid biofuel in the current biomass market, which is regulated by ENplus® certification scheme in the European-wide, ensuring the quality of product to consumers. Low heating value is the most important parameter of solid biofuel, and is strongly linked to total moisture content, so the control of moisture is key factor during pelletizing process. The original research carried out in this work allows to present the development of a NIRS prediction model for total moisture in wood pellets, in the range of values of 5 – 10 %, providing a much faster and more automated methodology for product quality control, both in production plants of wood pellets and in power plants with wood pellets as fuel. Keywords: near infrared spectroscopy, wood pellets, quality control, moisture, prediction model
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Sharapov, Evgenii, Christian Brischke y Holger Militz. "Assessment of Preservative-Treated Wooden Poles Using Drilling-Resistance Measurements". Forests 11, n.º 1 (21 de diciembre de 2019): 20. http://dx.doi.org/10.3390/f11010020.
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An IML-Resi PD-400 drilling tool with two types of spade drill bits (IML System GmbH, Wiesloch, Germany) was used to evaluate the internal conditions of 3 m wooden poles made from Scots pine (Pinus sylvestris L.). Drilling tests were performed on poles that were industrially vacuum-pressure-impregnated with a copper-based preservative (Korasit KS-M) and untreated reference poles. Both types of poles were subject to 10.5 years of in-ground exposure. Wood moisture content (MC) was measured using a resistance-type moisture meter. MC varied between 15% and 60% in the radial and axial directions in both treated and untreated poles. A higher MC was detected in the underground, top, and outer (sapwood) parts of the poles. Typical drilling-resistance (DR) profiles of poles with internal defects were analyzed. Preservative treatment had a significant influence on wood durability in the underground part of the poles. Based on DR measurements, we found that untreated wood that was in contact with soil was severely degraded by insects and wood-destroying fungi. Conversely, treated wood generally showed no reduction in DR or feeding resistance (FR). DR profiling is a potential method for the in-situ or in vitro assessment and quality monitoring of preservative treatments and wood durability. The technological benefits of using drill bits with one major cutting edge, instead of standard drill bits with center-spiked tips and two major cutting edges, were not evident. A new graphical method was applied to present DR data and their spatial distribution in the poles. Future studies should focus on the impact of preservative treatments, thermal modification, and chemical modification on the DR and FR of wood. This may further elucidate the predictive value of DR and FR for wood properties.
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Morales-Conde, M. Jesús, Carmen Rodríguez-Liñán y Paloma Rubio de Hita. "Application of Non-Destructive Techniques in the Inspection of the Wooden Roof of Historic Buildings: A Case Study". Advanced Materials Research 778 (septiembre de 2013): 233–42. http://dx.doi.org/10.4028/www.scientific.net/amr.778.233.
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The aim of this paper is to show the results of applying non-destructive inspection techniques (thermography, ultrasounds and microdrilling) during the inspection works of a protected building. These non-destructive techniques have been applied in the inspection of the wooden roof to identify deterioration, density loss and defects as a means of assessing its conservation status. This work concludes that the union of these nondestructive techniques constitutes an accurate diagnostic tool for the on-site inspection of wooden structures and the evaluation of their conditions. Thermography allows to distinct moisture contents while ultrasound detects density loss in areas of the wood with high moisture content.
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Naylor, Andrew, Phil Hackney, Noel Perera y Emil Clahr. "A predictive model for the cutting force in wood machining developed using mechanical properties". BioResources 7, n.º 3 (22 de mayo de 2012): 2883–94. http://dx.doi.org/10.15376/biores.7.3.2883-2894.
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In this study a number of work-piece variations were evaluated whilst limiting the cutting conditions. Eight wood species controlled at four moisture levels were machined along and across the wood grain. The tool used during cutting was designed to resemble a rip saw tooth with zero rake angle and narrow edge width. Each work-piece variation machined in the cutting tests was subjected to mechanical tests that evaluated bending properties across the grain and shear properties along the grain. The regression model establishes a relationship between the bending properties for cutting forces across the grain, as well as shear properties for cutting forces along the grain. F and R² values show that the elastic properties of the wood in bending and shear have less influence on the cutting forces when compared to the strength and toughness. Additionally, density is seen to have less influence on the cutting force along the grain. This is explained by the tool passing through an unquantifiable proportion of early and latewood fibers from the annual growth rings. Cutting across the grain, the tool is forced to machine through approximately the same proportion of earlywood and latewood fibres.
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Salonvaara, Mikael, Philip Boudreaux, Andre Desjarlais, Florian Antretter y Eric Werling. "Validation of Hygrothermal Simulations with Wall Performance Experiments in an Environmental Chamber". E3S Web of Conferences 172 (2020): 04010. http://dx.doi.org/10.1051/e3sconf/202017204010.
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Oak Ridge National Laboratory is developing a web tool, built on a rule-based expert system, that aids stakeholders in designing energy-efficient moisture-durable walls. Currently, the tool’s expert system database is mostly populated with expert opinion, but work is being done to incorporate durability assessment based on stochastic hygrothermal modeling. Chamber experiments have been conducted to validate the hygrothermal models. The measured temperature and humidity have been compared with those predicted by the hygrothermal model. Experiments and comparison to one-dimensional hygrothermal modeling results were completed with two walls, a Structural Insulated Panel (SIP) based wall and a Concrete Masonry Unit (CMU) based wall. The two walls were succumbed to typical Chicago weather in ORNL’s Heat, Air and Moisture chamber. The walls were sequentially exposed to different scenarios, including diffusion, wetting, air leakage and solar radiation. For the most part, the hygrothermal simulations can be successfully used to predict the performance of these wall systems for the moisture transport phenomenon. Errors between measured and simulated values decreased as measurements got closer to the interior side of the wall. The root mean square error was larger for relative humidity (up to 17.5%-RH for CMU) than for temperature (up to 4.5°C for CMU wall). The errors were larger for the CMU wall than the wood frame wall. The phenomenon, including liquid water, caused large discrepancies between measurement and simulation results, and simulated results showed slower drying of materials than measured results. The one-dimensional nature of the simulation model made simulating air leaks difficult but not impossible.
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Dupleix, Anna, Sid’ Ahmed Ould Ahmedou, Laurent Bleron, Frédéric Rossi y Mark Hughes. "Rational production of veneer by IR-heating of green wood during peeling: Modeling experiments". Holzforschung 67, n.º 1 (1 de enero de 2013): 53–58. http://dx.doi.org/10.1515/hf-2012-0005.
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Abstract Heating green wood logs by infrared (IR) radiation during peeling for veneer production has been numerically simulated, focusing on the heating kinetics of a green wood cylinder rotating with a decreasing radius. The results confirm those of previous experiments, that this kind of heating is a promising alternative to soaking wood prior to peeling. The model integrates the green wood parameters such as moisture content, density, distribution and ratios of earlywood and latewood, on the one hand, and the peeling conditions of veneer thickness and peeling speed, on the other. The following heat transfer processes were considered: conduction within the bolt, external heating by the IR source, and convection between the bolt surface and the external environment. The outputs were the temperatures of the bolt surface and of layers several millimeters deep. For maximal heat penetration, the bolt should turn in front of the IR source before cutting starts and the IR source should be positioned at the greatest angular distance ahead of the knife. Several heating scenarios could be simulated by the model, thus it is a useful decision-making tool for the design of an in-line IR heating system installed on the peeling lathe.
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Sandak, Anna, Mariapaola Riggio y Jakub Sandak. "Non Destructive Characterization of Wooden Members Using near Infrared Spectroscopy". Advanced Materials Research 778 (septiembre de 2013): 328–34. http://dx.doi.org/10.4028/www.scientific.net/amr.778.328.
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On site characterization of wood members is a very challenging task, after considering all the variables affecting the whole structure itself and material used for construction. The up-to-data procedures are limited to few characterizations, and in general based on visual assessment supported by local drilling resistance analysis, stress-wave time of flight measurement and/or moisture content estimation. The goal of this work was to promote near infrared (NIR) spectroscopy as a supplementary tool providing additional information for the expert assessing timber structures. The paper presents several examples of successful NIR application in species recognition, physical properties prediction, evaluation of wood weathering and/or fungal degradation level. However, it must be stated that implementation of NIR in routine assessment protocols requires prior preparation of a dedicated databases of high precision reference values to build reliable, flexible and sufficiently generalized models.
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Warguła, Łukasz, Dominik Wojtkowiak, Mateusz Kukla y Krzysztof Talaśka. "Symmetric Nature of Stress Distribution in the Elastic-Plastic Range of Pinus L. Pine Wood Samples Determined Experimentally and Using the Finite Element Method (FEM)". Symmetry 13, n.º 1 (29 de diciembre de 2020): 39. http://dx.doi.org/10.3390/sym13010039.
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This article presents the results of experimental research on the mechanical properties of pine wood (Pinus L. Sp. Pl. 1000. 1753). In the course of the research process, stress-strain curves were determined for cases of tensile, compression and shear of standardized shapes samples. The collected data set was used to determine several material constants such as: modulus of elasticity, shear modulus or yield point. The aim of the research was to determine the material properties necessary to develop the model used in the finite element analysis (FEM), which demonstrates the symmetrical nature of the stress distribution in the sample. This model will be used to analyze the process of grinding wood base materials in terms of the peak cutting force estimation and the tool geometry influence determination. The main purpose of the developed model will be to determine the maximum stress value necessary to estimate the destructive force for the tested wood sample. The tests were carried out for timber of around 8.74% and 19.9% moisture content (MC). Significant differences were found between the mechanical properties of wood depending on moisture content and the direction of the applied force depending on the arrangement of wood fibers. Unlike other studies in the literature, this one relates to all three stress states (tensile, compression and shear) in all significant directions (anatomical). To verify the usability of the determined mechanical parameters of wood, all three strength tests (tensile, compression and shear) were mapped in the FEM analysis. The accuracy of the model in determining the maximum destructive force of the material is equal to the average 8% (for tensile testing 14%, compression 2.5%, shear 6.5%), while the average coverage of the FEM characteristic with the results of the strength test in the field of elastic-plastic deformations with the adopted ±15% error overlap on average by about 77%. The analyses were performed in the ABAQUS/Standard 2020 program in the field of elastic-plastic deformations. Research with the use of numerical models after extension with a damage model will enable the design of energy-saving and durable grinding machines.
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Safarian, Sahar, Runar Unnthorsson y Christiaan Richter. "Simulation of small-scale waste biomass gasification integrated power production: acomparative performance analysis for timber and wood waste". International Journal of Applied Power Engineering (IJAPE) 9, n.º 2 (1 de agosto de 2020): 147. http://dx.doi.org/10.11591/ijape.v9.i2.pp147-152.
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<div data-canvas-width="75.53283108244308">A simulation model for integrated waste biomass gasification with cogeneration heat and power has been developed using Aspen Plus. The model can be used as a predictive tool for optimization of the gasifier performance. The system has been modeled in four stages. Firstly, moisture content of biomass is reduced. Secondly biomass is decomposed into its elements by specifying yield distribution. Then gasification reactions have been modeled using Gibbs free energy minimization approach. Finally, power is generated through the internal combustion engine as well as heat recovery system generator. In simulation study, the operating parameters like temperature, equivalence ratio (ER) and biomass moisture content are varied over wide range and their effect on syngas composition, low heating value (LHV) and electrical efficiency (EE) are investigated. Overally, increasing temperature and decreasing ER and MC lead to improvement of the gasification performance. However, for maximum electrical efficiency, it is important to find the optimal values of operating conditions.</div><div data-canvas-width="156.02508062890539">The optimum temperature, ER and MC of the down draft gasifier for timber and wood waste are 800 ̊C, 0.2- 0.3 and 5%. At such optimum conditions, CO and H</div><div>2 reach to the highest production and LHV and EE are around 7.064 MJ Nm-3 and 45%, respectively.</div>
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Ukrainetz, Nicholas K. y Gregory A. O’Neill. "An analysis of sensitivities contributing measurement error to Resistograph values". Canadian Journal of Forest Research 40, n.º 4 (abril de 2010): 806–11. http://dx.doi.org/10.1139/x10-019.
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As a hand-held, portable tool capable of assessing wood density of standing trees quickly and inexpensively, the Resistograph holds considerable potential application for evaluating forest genetics field tests. However, phenotypic correlations between Resistograph density index values and values from conventional wood density assessment techniques are weak. In an effort to investigate the extent to which environmental, operator, or instrument factors may affect density index values, we evaluated the sensitivity of Resistograph measurements to seven experimental factors. Drill bit flexion (a measure of operator steadiness), moisture content of wood, and air temperature significantly affected Resistograph density index values, while the influence of knots is minimized at a vertical distance of 3 cm. Battery type, sharpness of the drill bit (at least up to 350 uses), and battery charge (at least up to 310 uses with a 12 V motorcycle battery) had no significant effect on density index. By ensuring that the operator remains steady while drilling, sampling only live trees, only when air temperatures are above freezing, and by drilling at least 3 cm vertical distance from knots, measurement error should be minimized. Three measurements per tree are required to estimate density index to within 3 units 19 times out of 20.
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Agrawal, Akshita y Sheetal Chopra. "Sustainable dyeing of selected natural and synthetic fabrics using waste teak leaves (Tectona Grandis L.)". Research Journal of Textile and Apparel 24, n.º 4 (6 de agosto de 2020): 357–74. http://dx.doi.org/10.1108/rjta-05-2020-0046.
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Purpose This paper aims to extract the dye colourant from teak leaves using different aqueous mediums (Alkaline, Neutral and Acidic); to characterize the dye in terms of yield %; ash content and moisture content; to standardize the conditions of application of dye extracted from teak leaves on selected natural and synthetic fabrics using selected natural and chemical mordants; to assess the colour value (K/S, L*, c*/ h*, a*, b*) and fastness properties of the dyed samples in terms of wash, rub, light and perspiration fastness; and to develop dyed and printed designs using combinations of mordant and extracted dye. Design/methodology/approach Stage 1 – Extraction of dye from teak leaves; and characterization of dye: yield% ash content and moisture content. Stage 2 – Preparation of fabrics for dyeing; optimization of mordanting parameters using pre mordanting method followed by post mordanting; and optimization of dyeing parameters. Stage 3 – Testing of dyed fabric – Colour Measurement; K/S L*a*b*/L*c*h*; fastness properties; wash fastness done in the Laundrometer using ISO 2 standard test method; crock fastness done by Crockmeter using AATCC 116–1995 test method; perspiration fastness tested by perspirometer using AATCC 15– 2007 test method; and light fastness assessment in Mercury Bulb Tungsten Filament (MBTF) light fastness tester using AATCC Test Method 16–2004. Findings The findings of the study show that waste teak leaves can be used as an effective dye for natural as well as synthetic fabrics giving a wide range of colours on wool, silk and nylon. The maximum relative colour strength of the extracted dye on unmordanted dyed samples was found to be at pH 5 on wool and silk and at pH 7 on nylon. A range of shades was obtained with the use of different mordants. The extracted dye showed moderate to good fastness properties in terms of light, wash, rub and perspiration on wool and silk and excellent on nylon. Fastness properties were found to improve with the application of mordants both as pre and post method. Various combinations of mordants and dye result in obtaining pleasing and harmonious colours which were used aesthetically for printing. Research limitations/implications Due to time constrains, extraction in an organic medium could not be done, which could be a further scope for study. Practical implications Dyeing using teak leaves is a step towards sustainability and effective waste utilization with promising potential for application on natural as well as synthetic fabrics. Good colour with added properties will provide excellent solutions for eco-friendly methods of dyeing. Social implications This paper demonstrates the new possibilities offered by innovative uses of by-products of the timber industry and open good prospects for alternatives to synthetic colourants and new markets for the textile industry. It offers a new tool for the development of slow fashion. Originality/value It is a common practice to prune the tree branches to improve wood quality; thus, leaves are easily available as by product from pruning and also from wood harvesting. In the present study, waste teak leaves (Tectona grandis L.) were used for the extraction of dye.