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-1. Average moisture content of green wood, by species

-1. Average moisture content of green wood, by species

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Wood, like many natural materials, is hygroscopic; it takes on moisture from the surrounding environment. Moisture exchange between wood and air depends on the relative humidity and temperature of the air and the current amount of water in the wood. This moisture relationship has an important influence on wood properties and performance. Many of th...

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... To evaluate the moisture in the NLT, the temperature and RH data acquired from the thermo-hygrometers were converted into EMC using Eq. 1 (Glass and Zelinka 2010) based on the Hailwood-Horrobin sorption model (Hailwood and Horrobin 1946), bioresources.com Hwang et al. (2023). ...
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A timber-concrete composite (TCC) slab composed of nail-laminated timber (NLT) and topping concrete (TC) was developed for flooring applications. The NLT was laminated alternately with lumber and plywood. To investigate the nonstructural dimensional behavior of the TCC slab, the temperature, relative humidity (RH), and dimensional changes of the slab exposed to outdoor air were monitored for 205 days. Temperature change was transmitted directly to both components, and RH change was transmitted gradually to the NLT. Concrete pouring caused a sharp increase in NLT width, which was the laminating direction of the nails. This resulted from swelling of the wood owing to the moisture in the concrete mixture and loosening of the nail lamination. The member composition for the nail-laminating system, fastener type, and concrete volume help to secure the dimensional stability of the NLT. Cracks in the TC caused width deformation, which was recovered by drying shrinkage of the TC. Correlation analysis among temperature, RH, and strain indicated that dimensional changes in NLT correlated strongly with RH, while those in TC correlated strongly with temperature. The correlation between longitudinal strain in the TC and strain in the three directions of the NLT was attributed to the notches designed for mechanical connection.
... The scrimber is denser than the other timbers. The lower moisture content of scrimber also indicates the less available void for free water [62]. ...
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... The branch and trunk of the living tree or the freshly sawn wood are examples of green wood. The green wood moisture content ranges from 31% to 239% [31][32][33], generally higher than the fiber saturation point (FSP). Researchers proposed various methods to measure the FSP value, which resulted in varied result values [34]. ...
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... Wood is extensively utilized in household and engineering applications and thus has a wide range of MC values in service. At normal ambient temperature range MCs of dry and green woods can be up to 30% and 200% [358,359], respectively. MC in wood may change its thermal response greatly. ...
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... Moisture content (MC) of wood also affects its resistance to decay and insects as well as its preservative treatment (Tsoumis 1991). At constant temperature (T) and relative humidity (RH), wood reaches an equilibrium state characterized by a certain equilibrium moisture content (EMC) (Glass Samuel and Zelinka 2010). A sorption isotherm is a discrete representation of equilibrium moisture states of wood with its surrounding environment and each state is attained after either adsorption or desorption of water molecules (Engelund et al. 2013). ...
... The EMC is also affected by the wood sample history and, this phenomenon is known as sorption hysteresis. As an example, when a greenwood sample is dried, its EMC reached for adsorption will be lower than its EMC attained for desorption (Glass Samuel and Zelinka 2010). Furthermore, it has been noticed that around 60-70% RH, the sorption isotherm of wood exhibits an upward bend. ...
... RH = 94% was reached by using a saturated saline solution of potassium sulfate (K 2 SO 4 ) (Nilsson 2018). It is important to notice that, without considering the sample history (Glass Samuel and Zelinka 2010), the EMC of wood at the three RH levels can be predicted by the EMC calculation table (Noack 1989;W.T. Simpson 1998;Glass Samuel and Zelinka 2010) and it is expected to be approximately 9%, 15%, and 24%, respectively. ...
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... Kadar air didefinisikan sebagai banyaknya air atau massa air yang terdapat di dalam kayu, yang dinyatakan persen terhadap berat kering tanur [19,20]. Gambar 2a menunjukkan nilai rata-rata kadar air kayu agathis, pinus, meranti, dan mahoni berturut-turut adalah sebesar 15.17%, 15.46%, 15.23% dan 14.00%. ...
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The use of wood as a building material must be designed quite rigid and strong. According to SNI 7973:2013, the corrected design value on the wooden structure components must be in accordance with the condition of wood to be used. The objective of this study is to determine the value of timber beams stability (CL) both of softwood and hardwood based on SNI 7973:2013 for construction purposes. The material in this research to be used are pine (Pinus merkusii), agathis (Agathis dammara), mahagony (Swietenia macrophylla), and red meranti (Shorea leprosula). Testing of physical properties include moisture content, specific gravity, and density, meanwhile testing of mechanical properties include flexural strength, modulus of elasticity, and ductility. Mechanical testing is carried out on a small clear specimens and full-size specimens, while the physical properties are tested only on a small clear specimens. The full-size specimens are visually sorted and the strength ratio (S) is determined prior to mechanical testing. The result of this study showed that the highest strength ratio was in meranti 55.85%, agathis 52.98%, pine 46.76%, and mahogany 46.60%. Softwood has a lower S value to more knot defects than hardwood. The slenderness ratios of agathis, pine, mahogany, and meranti wood respectively are 7.48, 7.45, 7.40 and 7.66 so that all specimens are referred to as short beams. The value of beam stability (CL) is close to 1 that indicates that the beams are stable and does not twist.
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... The expansion of wood due to heat and moisture exposure is well-documented. The process induces cracking and fracturing of the wood cell matrix (Glass and Zelinka, 2010). In the case of engineered wood products such as particleboard the volumetric expansion breaks the bonds between the constituent wood particles and reduces the strength of the products, which consequently caused them to be more susceptible to fragmentation (Carll and Wiedenhoeft, 2009). ...
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Highlights A unique model representing transient heat of wetting along with the dimensional expansion of wood pellets exposed to humid environment was developed. The model was validated by placing a pellet inside a controlled humidity chamber and continuously recorded the pellet’s temperature and moisture. The performance of the model for predicting the pellet’s cross-over temperature above the surrounding temperature was tested for a range of humid conditions from 0% to 95% RH. Abstract . Wood pellets are exposed to incidental humid conditions during postproduction and handling. It is well known that the heat of moisture adsorption contributes to the self-heating of the pellets. The aim of this research is to quantify the temperature rise of the pellets due to the heat of wetting. The modeling was accomplished by developing and validating a set of mass and energy conservation equations for solid, liquid, and vapor fractions. An exponential function represents the heat of wetting as a function of adsorbed moisture. A nonlinear model describes the increase in the pellet’s diameter. For model validation, the center temperature of a pellet was recorded in a humidity chamber set at 33°C. The model successfully predicted the pellet’s temperature increase from the initial 25°C to a maximum temperature of 36°C, surpassing 33°C after about 5 minutes. Keywords: Heat of moisture adsorption, Heat transfer, Moisture transfer, Self-heating, Wood pellet.
... The computational model allows simulations of any type of wood particles, by inserting specific properties as input data. For many species of wood, properties such as moisture content and specific gravity can be found in [7]. ...
... It was assumed that and are functions of . Empirical correlations from [7] were used to set these properties. ...
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The objective of this work is to study heat and mass transfer processes in a single biomass particle before its thermal degradation (< 200 o C) under high intense acoustic fields. For that, was developed a numerical code for Biot number higher that one, i.e., non-isothermal particles. The hypothesis is that an acoustic field alters the interaction between the gas and particles, proving drying. Acoustic fields can be obtained by using a loudspeaker inside a reactor. The proposed model predicts moisture mass transfer completion for different particle sizes and oscillating frequencies. The obtained data are relevant for plant conversion capacity and reactor's preliminary design.
... Kontrol örneklerine göre ön ısıl işlemin eğilme direncini azalttığı, fakat tanen takviyeli ön ısıl işlemli 10°C sıcaklık %50 bağıl nemde iklimlendirilmiş örneklerin eğilme direncinde artışlara neden olduğu belirlenmiştir. Ağaç malzemenin mekanik özelliklerindeki artış ve azalışlar genellikle yıllık halka düzeni, lif yapısı, ağacın yoğunluğu gibi yapısal özelliklerinin yanı sıra malzemenin sıcaklığı ve nem içeriğinin karmaşık bir etkileşimine de bağlıdır [27][28][29]. Sıcaklık ve rutubet miktarının, ağaç malzeme mekanik özelliklerinin üzerinde önemli bir etkisi vardır. Ağaç malzeme bünyesindeki lif doygunluğu rutubet miktarının ortalama %30'un altına düşmesi ve sıcaklığın azalmasıyla mekanik özelliklerde artış görülmektedir [30]. ...
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In this study, the behavior of tannin-modified and pre-heat treated wooden beams in different climatic conditions were determined. For this purpose; Samples prepared according to TS EN 386 standards from Scots pine (Pinus sylvestris L.), oak (Quercus petraea L.) and chestnut (Castanea sativa Mill.) woods were impregnated with acorn tannin and pre-heated for 2 hours at 150°C and 160°C. After the samples were conditioned at 20°C temperature and 65% RH, 40°C temperature and 35% RH, 10°C temperature and 50% RH, bending strength tests according to TS 2474 and modulus of elasticity in bending according to TS 2478 were applied. As a result; At the level of wood species-process type interaction, the highest increase in bending strength was determined as 7.6% in tannin modified scotch pine samples at 150ºC compared to the control samples. Accordingly, it can be suggested to use Scotch pine wood in the manufacture of lightly loaded wooden house columns and beams and other building elements.