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When oil palm lumber is considered for load-bearing products such as glued laminated timber (GLT), defined strength and stiffness values are required. In this investigation, combined GLT from oil palm wood is tested in compression parallel and perpendicular and glulam lamellas in tension parallel to the vascular bundles. Strength and Young´s modulus in compression and tension parallel increase with the density by power law relationship. In contrast to dicotyle-dons, the strength in construction size exceeds that of small, defect-free test specimens (compression strength perpendicular), are in the same range (tensile and bending strength parallel) or only a little below (compression strength parallel). The specimen size does not influence the strength. The ratio of fc,0 : fm : ft,0 is 1.2 : 0.8 ... 1.7 ... 2.6 : 1 and fc,0 : fc,90 = 2.7 ... 13.0 ... 32.6 : 1 for ρ = 200 ... 400 ... 600 kg/m³; the ratio of Ec,0 : Em : Et,0 is 1.2 : 1.3 : 1 for ρ = 400 kg/m³. Ashby´s performance indices for minimum weight design rise with the density; the strength-density performance indices are comparable or only slightly lower than that for structural size softwood, whereas the modulus-density performance indices are much lower. The challenge in use of oil palm wood for load-bearing construction products is the low stiffness. [ABSTRACT FROM AUTHOR]

Supply chain instabilities and inflated material prices have had a disruptive impact on cost estimating of construction projects. While several research efforts used national macroeconomic indicators to forecast the prices of domestically produced construction materials, none of the existing studies investigated whether the lagged macroeconomic indicators of the main trading partners could enhance the predictability of the prices of cement, steel, and lumber in the US construction sector. This paper fills this knowledge gap. The authors adopted a multi-step methodology that included: (1) collecting data on the target variables and the candidate leading indicators; (2) identifying the structural breaks in the collected data sets; (3) conducting causality tests to identify short-term associations and cointegration tests to examine long-term relationships; (4) developing vector error correction (VEC) models to forecast the prices in the short and long terms; and (5) evaluating the performance of the proposed models against existing forecasting models in the literature. Results of the Granger test and Johansen test indicate that Canada's overall producer price index (PPI) is a consistent leading indicator of the prices of cement, and Mexico's overall PPI is a consistent leading indicator of the prices of steel. Findings indicate no statistical evidence to suggest that neither Canada's PPI nor Mexico's PPI can be leading indicators of lumber prices. Over an 18-month ahead of sample horizon, the presented VEC models of cement and steel prices outperformed existing models, particularly beyond the 1-year-ahead forecasts. Utilization of the proposed forecasting models can significantly enhance the accuracy of cost estimates and feasibility studies of construction projects. This provides proactive financial planning for construction contractors and project owners through improved short- and long-term forecasting of the prices of main construction materials. [ABSTRACT FROM AUTHOR]

Water vapour diffusion resistance of solid wood panels and laminated veneer lumber panels The material composition of wood and adhesive is influenced by numerous factors during the bonding process, which is why the water vapour diffusion resistance (WVDR) of wood‐based panels is subject to a certain degree of variation. In this work, self and industrially produced panels were tested for their WVDR in dry and humid test climates. The tests show that the results are highly dependent on the corresponding adhesive system, the adhesive quantity and the board thickness. Additional evaluations of the adhesive joint formation using a microscope show a correlation between the WVDR and the thickness of the pure adhesive film. A comparison of the measured values with the information in the data sheets reveals a considerable difference. It can be concluded from this that in future the normative regulation for determining the WVDR for the product declaration should not be determined using list values, but rather measured for each product in accordance with standard EN ISO 12572. [ABSTRACT FROM AUTHOR]

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To rigorously analyze the effects of high-salt environments on dimension lumber and provide scientific and reliable data to facilitate the advancement of light-frame construction in such environments, this study subjected dimension lumber to salt solution treatment. The study investigated the trend of nail-holding power variations across the radial, tangential, and cross-sections of spruce–pine–fir (SPF) dimension lumber under varying salt concentrations and treatment durations. The experimental results exhibited a significant influence of salt on the nail-holding power across all sections of the SPF dimension lumber. As the concentration of salt solution increased, the holding power gradually decreased across all directions, exhibiting considerable differences across salinity gradients. Specifically, the radial and tangential sections exhibited a 15%–20% higher nail-holding power compared to the cross-section. An increase in the salt solution concentration above 3% corresponded to an approximate 1% decrement in nail-holding power per section for every 0.5% rise in concentration. Additionally, prolonged salt treatment initially resulted in an increase, followed by a subsequent decrease in nail-holding power, demonstrating a consistent pattern across all variations. Post hoc analyses confirmed that the differences between individual salt concentrations, including between 3.5%, 4%, and 4.5%, were statistically significant. These findings provide valuable data for understanding the degradation of timber connectors in high-salt environments, contributing to the development of more durable and resilient wood-frame buildings in such conditions. [ABSTRACT FROM AUTHOR]

The effect of sticker thickness on final moisture content (MC) of southern pine lumber was investigated in this work. Three kiln charges of lumber were dried to examine the impact of sticker thickness. Sticker thicknesses were 0.75-, 1.00-, and 1.25-in. The moisture contents at different locations within the kiln pack (edge vs middle / course position) were noted. Three course positions were top 5, middle, and bottom 5 courses. Two within-pack locations were considered: outer 25% and middle 50%. Drying time decreased as sticker thickness increased from 0.75 in. to 1.00 in. Statistically significant interactions were noted for sticker thickness and course position (<0.0001) as well as location and course position (P= 0.0378); 1.25 in. thick stickers exhibited higher MC in comparison to 0.75 in. and 1.0 in. for top to bottom positions. Additionally, 1.0 in. thick stickers developed lower MC at the top and bottom. Lower MC was observed in outer relative to inner location regardless of course position. Lower MCs were observed at the top courses for both inner and outer location. The 1.25 in. thick stickers did not produce acceptably dry lumber given the production time constraint. The results suggested that 1.0 in. sticker thickness was most favorable. [ABSTRACT FROM AUTHOR]

This work deals with the determination of some properties of laminated veneer lumber (LVL) made from tropical hardwoods, specifically focusing on Cameroonian woods. The LVL samples are manufactured using veneer from three tropical wood species: Ayous, Ilomba, and Bete. Two types of adhesives are used: a neoprene contact adhesive (Magpow) and a white vinyl adhesive (Nemo). The specimens have undergone multiple drying cycles, and hundreds of samples from each species have been selected with dimensions of 1 cm × 1 cm × 1 cm. These samples are then machined according to the specific wood grain of each species. The experiments conducted aim to determine properties such as moisture content, densities, volume swelling, shrinkage coefficients, and the hygroscopic point of equilibrium of the samples. Swelling and shrinkage measurements allow for the visualization of sample dimensions in relation to humidity levels, and the hysteresis of the adsorption phenomenon of the LVL is also obtained. The results show that regardless of the type of adhesive or veneer used, LVLs are denser than the wood they are made from. For each type of LVL, the ratio between the mass of a sample saturated in water and the mass of the dried sample remains constant. The rule of mixture is investigated, and the density properties of materials and the vacuum rates of LVL samples are compared with experimental data. [ABSTRACT FROM AUTHOR]

Trembling aspen (Populus tremuloides) is one of the major species within Populus, a predominant genus of hardwoods in North America. However, its utilization has been limited to pulp and paper or wood-based composite boards. This study aimed at evaluating the major physical and mechanical properties of trembling aspen lumber, with an ultimate objective of using this species to produce engineered wood products (EWPs). The testing materials consisted of 2 × 4 (38 mm × 89 mm) trembling aspen lumber pieces in lengths of 8, 10, and 12 feet (2.44, 3.05, and 3.66 m) with two visual grades, select structural (SS) and No. 2. Machine Stress-Rated (MSR), and longitudinal stress wave (LSW), edgewise third-point bending (EWB), and axial tension tests were conducted on the lumber. It was found that, (1) by increasing the maximum knot size by a half-inch from one-quarter inch, the minimum modulus of elasticity (MOE) measured using the MSR, the mean, and the fifth-percentile ultimate tensile strength (UTS) decreased by about 8.8%, 20.1%, and 29.8%, respectively. (2) Approximately 44% of the trembling aspen lumber met the 1450f-1.3E grade for MSR lumber, and 62% qualified for the 1200f-1.2E grade. (3) There was a great potential for manufacturing cross-laminated timber (CLT) of grade E3, with a rejection rate of about 29%. (4) The mean UTS and MOE values of the SS-grade trembling aspen lumber were 22.88 MPa and 9519 MPa, respectively, being 25.5% and 11.3% lower than that of Spruce–Pine–Fir (S-P-F) lumber. The fifth-percentile UTS and MOE values were 11.57 MPa and 7404 MPa, respectively, marking a decrease of 13.3% and 1.5% compared to the S-P-F lumber. (5) The oven-dried specific gravity (SG) of the trembling aspen wood was 0.40, which was about 3.5% larger than the value provided in the Wood Handbook. [ABSTRACT FROM AUTHOR]

Among the many benefits of implementing numerical analysis on real objects, economic and environmental considerations are likely the most important ones. Nonetheless, it is also crucial to constrain the duration and space necessary for conducting experimental investigations. Although these benefits are clear, the applicability of such models must be appropriately verified. This research subjected validation of numerical models depicting the behavior of unstrengthened and strengthened laminated veneer lumber (LVL) beams. As a reinforcement, a carbon fiber reinforced polymer (CFRP) sheet and laminates were used. Experiments were conducted on full-scale members within the framework of the so-called four-point bending testing method. Numerical simulations were performed using the Abaqus software. Two types of material models were examined for laminated veneer lumber: linearly elastic and linearly elastic–perfectly plastic with Hill's yield criterion. A distinction was made in the material properties of carbon composites based on their location on the height of the cross-section. The outlined numerical models accurately depict the behavior of real structural elements. The precision of predicting load-bearing capacity amounts to a few percent for strengthened beams and a maximum of eleven percent for unstrengthened beams. The relative deviation between numerical and experimental values of bending stiffness was at a maximum of seven percent. Applying the elastic–plastic model enables accurate representation of the load versus deflection relation and the distribution of stress and deformation of strengthened beams. Based on the findings, directives were provided for further optimization of the positioning of composite reinforcement along the span of the beam. Reinforcement design of existing laminated veneer lumber members can be made using presented methodology. [ABSTRACT FROM AUTHOR]

Spiral grains are one of the most important tree growth defects that can remarkably affect the shape stability of lumber. This growth defect is observed by an oblique arrangement of axially oriented cell elements in the wood. This research focused on identifying and measuring selected shape changes caused by the spiral grains in the log. Hornbeam logs with spiral grain and with no spiral grain aged 60 and 52 years were selected to detect shape changes. Following the research and the norms of STN EN 1309-3 (49 1013), DIN (4074-5), and ASTM D245, it can be stated that spiral grain is an essential factor affecting the shape stability of hornbeam lumber. In the case of lumber with spiral grain, the spiral grain increased by up to 8° within three months. The warp of both types (bow, crook) increased exponentially throughout the study, peaking between the third and fourth week with an increase in warp bow of 26 mm and 17 mm in warp crook. [ABSTRACT FROM AUTHOR]

Deformation and surface-checking defects in wood are closely related to the drying stress caused by shrinkage and moisture content (MC) gradients throughout the drying process. In this study, 50-mm-thick Masson pine (Pinus massoniana Lamb.) lumber was used as the research object. The drying stress caused by shrinkage behavior and MC changes was monitored, and the development of surface checks was observed during the drying process. Results showed that when the average MC was 60%, the free water in the surface layer of lumber evaporated completely, causing the MC to decrease below the fiber saturation point (FSP). The surface layer was subjected to tension stresses, resulting in surface checks which primarily distributed in the latewood area and propagated longitudinally. When the average MC was between 30% and 40%, the combined effects of the high MC gradient and anisotropic shrinkage of the wood resulted in further expansion of the checks. As the average MC decreased to less than 20%, the MC of the core layer lumber decreased below the FSP, resulting in the closure or even disappearance of most surface checks. The critical point (average MC of 60%) of drying stress was obtained, which can benefit the fine-tuning of kiln-drying schedules and improve the drying quality of Masson pine wood. [ABSTRACT FROM AUTHOR]

Simple Summary: In our study, we explored ways to effectively trap invasive ambrosia beetles, which pose significant threats to trees and forests. We focused on comparing two types of bait—pure ethanol and denatured ethanol—to attract these pests in different environments like tree nurseries and orchards. We found that traps using pure ethanol captured more Xylosandrus germanus beetles compared to those with denatured ethanol. Our findings suggest that using pure ethanol could be more effective for monitoring certain ambrosia beetle species. This research contributes to better pest management strategies, helping protect trees from invasive pests, ultimately benefiting society by safeguarding ecosystems and agricultural productivity. Ambrosia beetles, particularly invasive species within the tribe Xyleborini, such as Xylosandrus germanus (Blandford, 1894), pose significant threats to various ecosystems and managed habitats worldwide. Monitoring these invaders is vital for effective pest management, typically accomplished through ethanol-baited traps. We compared trap efficacy using denatured ethanol versus absolute ethanol in orchards, tree nurseries, and lumber yards in northeastern Ohio, USA, finding that absolute ethanol traps captured significantly more X. germanus. Analysis revealed acetone, ethanol, and methyl isobutyl ketone in the denatured ethanol, likely impacting trap efficacy. Our study underscores the importance of using pure denatured ethanol without acetone for effective monitoring, especially for X. germanus. Exotic xyleborines dominated trap captures across various habitats, emphasizing the need for tailored pest management strategies. Further research is warranted to explore the chemical ecology of ambrosia beetles and the influence of ethanol impurities on trap effectiveness. [ABSTRACT FROM AUTHOR]

The increasing availability of mass timber panels has expanded the possibilities for using timber-concrete-composite (TCC) flat floors beyond the traditional TCC T-beams. While TCC floors often easily satisfy ultimate limit state requirements, their stiffness, vibration characteristics, and long-term performance are critical design considerations. This research aimed to validate the bending, vibration, and long-term performance for nine different TCC floor systems through full-size tests with a span of 5.8 m. The tested floor systems used laminated-veneer-lumber, laminated-strand lumber, and cross-laminated-timber (CLT) panels connected to a concrete slab with and without an interlayer. Three types of shear connections were employed: self-tapping screws; glued-in steel mesh; and a combination of STS and adhesive bond. First, the shear connection properties were determined via 54 small-scale push-out tests. Then, 18 floors were tested in bending and vibration shortly after fabrication, and an additional nine floors were subjected to service loading for 32 months under variable climatic conditions, after which they were subjected to bending and vibration tests. The results confirmed that the calculations based on the γ -method accurately predict the stiffness, natural frequency, and governing failure modes of TCC floors. The long-term exposure to service loading had minimal effect (within 10%) on resistance, stiffness, and natural frequency of TCC floors, except for the TCC using CLT, which showed the highest creep deflection and stiffness reduction among the tested configurations. [ABSTRACT FROM AUTHOR]

Background and purpose: This study was conducted with the aim of investigating parallel strand lumber (PSL) made from reed residue and laminated veneer lumber (LVL) obtained from poplar wood reinforced with glass fiber reinforced polymer (FRP) using epoxy resin. Materials and methods: The independent variable was FRP reinforcement for either LVL or PSL and control sample either LVL or LSL without FRP. The mechanical properties of the manufactured boards including bending strength (MOR) and modulus of elasticity (MOE) in the width and edge of the test sample, shear strength, compression strength parallel to the grain, internal bonding and screw withdrawal strengths were investigated as dependent variables. The obtained results were analyzed using completely randomized design and SPSS software. Results: Results showed that for all studied mechanical properties, the use of FRP increased the strength the PSL and LVL panels. For LVL, the effect of strengthening the samples with FRP was significant at the level of 1% and also for the modulus of rupture of the width and edge samples showed an increase of 93% and 59%, respectively. The value of MOE for samples reinforced with FRP showed an increase of 89.6 and 132% for the width and length of the PSL samples, respectively. For LVL, the MOE value of the width and edge of the samples increased by 54 and 95.5% with reinforcement. Reinforced PSL samples have improved shear strength by 31%, while this value was only 2.5% for LVL. In case of internal bonding, reinforcement with FRP improved the internal bonding strength of the samples by 92%. Screw withdrawal strengths improved by 27% due to the strengthening of the test samples by FRP. Conclusion: According to the results, it can be stated that the use of glass fibers and epoxy resin has a significant positive effect on the mechanical strength of PSL made of reed and LVL and it is possible to use low quality raw materials such as reed and low quality poplar wood layers. [ABSTRACT FROM AUTHOR]

In this study, the rotating welding process of Chinese fir (Keteleeriafortunei) in Guizhou, China, was systematically analyzed. The effects of rotating welding conditions, including the dowel-to-guide hole diameter ratio, welding time, depth, base surface, angle, and dowel type, on the performance of welded Chinese fir were explored. Moreover, the physical and chemical changes oftheChinese fir interface during welding were revealed by Fourier-Transform Infrared Spectroscopy (FT-IR), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). The results indicated the following: (1) The rotating welding technology can quickly achieve a strong connection between wood through friction heat without chemical adhesives and compared with traditional wood connection technology such as gluing or mechanical fixing;it has the advantages of simple operation, high production efficiency; and environmental friendliness. (2) Aftertherotating welding, the wood underwent significant pyrolysis, especially the degradation of hemicellulose. The heat generated in the welding process caused good melting and mechanical interlocking between the dowel and the wall of the guide hole, but it was also accompanied by afriction loss of the dowel and the substrate. (3) The welding parameters affected the wood's connection strength and stability by altering heat production, distribution, transfer, and frictional losses. The impact of the dowel-to-guide hole diameter ratio had a great influence on the connection strength. When the diameter ratio was 1:0.7, the tensile strength was the highest, reaching 2.27 MPa. (4) The analyses of XPS, FTIR, XRD, and SEM proved thatthechemical composition changes at the interface, leading to a more structured crystalline bond and enhanced connection strength due to fiber entanglement and interlocking. This research providesatheoretical and experimental basis forthefurther innovation and development of wood processing technology and provides a new technical path forthegreen manufacturing of wood structure buildings. [ABSTRACT FROM AUTHOR]

Metal-plate-connected joints (MPC) are widely used in light timber buildings, while there are fewer studies on the joints under dynamic loads. For purpose of exploring a new possibility of application in bamboo structures, laminated bamboo lumber (LBL) and MPC have been incorporated in the current test. Four groups of metal-plate-connected tension joints using laminated bamboo lumber (LBL-MPC) are considered to be loaded by static and cyclic loading. Test specimens AA and AE refer to pairs of LBL member connected end-to-end in parallel, loaded in tension, connected with a rectangular shaped MPC oriented longitudinally (AA) or with the MPC oriented transversely (AE). Test specimens EA and EE refer to pairs of LBL members connected perpendicular, with a tension load on one of the members that imparts a perpendicular-to-grain loading on the other member. Both static and cyclic tests were performed using a displacement-controlled loading method with a loading rate of 1 mm/min. Under cyclic loading, the ultimate load of AA, AE, and EA joints was 7.6%, 10.4%, and 5.8% higher than that under static load, while EE joints were reduced by 6.4%. Two categories of skeleton curve models adapted to tensile joints of LBL-MPCs under cyclic loading were proposed. [ABSTRACT FROM AUTHOR]

Hevea brasiliensis (rubber tree), a major source of natural rubber, could also be an important source of lumber as senescence occurs. However, latex collection is known to affect Hevea brasiliensis (rubber tree) wood formation and consequently, wood properties. The impact tapping (cutting made in the bark of the tree for latex harvest) has on the tree and the way the tree responds after tapping is often overlooked. Knowledge on wood properties of tapped rubber trees in Nigeria would enhance its sustainable utilization which is especially important in developing countries where lumber is limited. Variation in specific gravity and shrinkage of rubberwood wood due to tapping duration was examined. Tapping duration had significant effect in specific gravity and longitudinal shrinkage of rubberwood but had no effect on tangential and radial shrinkage. The specific gravity (SG) of rubberwood ranged from 0,55 - 0,59. Longitudinal shrinkage (average 1,42 %) was higher than typically observed for mature wood. Average tangential shrinkage for rubberwood of all the ages was 5,37 % while radial shrinkage ranged from 2,87 % to 3,84 %. decrease in SG observed in trees tapped for 20 years may indicate the initiation of senescence. Tapped rubberwood could be used in areas not exposed to high moisture as well as in other wood composites.

This research paper studies the influence that the number of plies has on the identification of the mechanical properties of poplar Laminated Veneer Lumber (LVL) from tensile tests such as its stiffness. LVL poplar specimens were prepared with different ply configurations and subjected to uniaxial tensile tests. Both longitudinal and transverse stiffnesses were characterized in this research. The results show that the ply configuration influences the mechanical properties. The influence of the glued faces, the presence of lathe checks, and the compression ratio of veneers were studied during the manufacturing of the LVL. All these results provide valuable information for the design and optimization of laminated wood structures. An analytical modelling strategy is proposed to account for the effect of ply numbers, ply orientations, the compression ratio of veneers and the glue used on the stiffness of poplar laminate both in longitudinal and transverse directions. [ABSTRACT FROM AUTHOR]

This study presents a whole building life cycle assessment for a 265 m2 end- terrace home built in Michigan, United States. The study scrutinized the embodied carbon footprint of conventional construction materials, focusing on high-impact materials like concrete, steel, gypsum, paint, and insulation. Stages from raw material extraction to transportation and processing of the raw materials into finished products and transportation of finished products to the site are considered. The baseline materials contributed to approximately 28,450 kg CO[sub 2]e, equivalent to 107.35 kg CO[sub 2]e/m2. A notable reduction in the embodied carbon footprint, ranging from 19% to 39%, was observed by substituting with 'like-for-like' alternatives. However, the study highlighted challenges in shifting to low-embodied carbon materials, primarily due to limited market readiness and scalability of some eco-friendly options. The study also assessed the feasibility of these alternatives using the United States Department of Energy's "Technology Readiness Level" framework, examining their current production capacity, estimating potential future demand, and identifying key development areas to meet net-zero carbon goals effectively. This comprehensive approach underscores the complexity of transitioning to low embodied-carbon building practices while balancing feasibility and environmental impact. [ABSTRACT FROM AUTHOR]

The International Atomic Energy Agency, as part of the new regional project (RAF/9/059), recommend the establishment of diagnostic reference levels (DRLs) in Africa. In response to this recommendation, this project was designed to establish and utilise national DRLs of routine computed tomography (CT) examinations. These were done by estimating CT dose index and dose length product (DLP) from a minimum of 20 patient dose report of the most frequently used procedures using 75th percentile distribution of the median values. In all, 22 centres that formed 54% of all CT equipment in the country took part in this study. Additionally, a total of 2156 adult patients dose report were randomly selected, with a percentage distribution of 60, 12, 21 and 7% for head, chest, abdomen–pelvis and lumber spine, respectively. The established DRL for volume CT dose index were 60.0, 15.7, 20.5 and 23.8 mGy for head, chest, abdomen–pelvis and lumber spine, respectively. While the established DRL for DLP were 962.9, 1102.8, 1393.5 and 824.6 mGy-cm for head, chest, abdomen–pelvis, and lumber spine, respectively. These preliminary results were comparable with data from 16 other African countries, European Commission and the International Commission on Radiological Protection. Hence, this study would serve as a baseline for the establishment of a more generalised regional and national adult DRLs for Africa and other developing countries. [ABSTRACT FROM AUTHOR]

The effect of densification of the laminas was studied relative to the shear performance of cross-laminated timber (CLT) specimens submitted to the bending test. The three-layered CLT panels were fabricated using loblolly pine (Pinus taeda L.). A compression ratio (CR) of 50% was used to densify the lumber using the thermomechanical densification technique. The process included plasticizing the lumbers by soaking them in boiling water for 10 minutes and then hot-pressing to the target thickness at 140 °C. Four groups were made, i.e., a control sample with all three layers nondensified, only mid-layer densified, all layers densified, and all layers planed to the same thickness of densified layers. Specimens were tested in short-span bending with a span-to-depth ratio of eight. For specimens having densified mid-layer, the failure mode changed from rolling shear to tensile failure of the outer layer, and the maximum shear stress was increased by 34%. Densification of the mid-layer at CR of 16% was sufficient to change the failure mode from rolling shear in mid-layer to tensile in outer layer. In the case of all-layer-densified specimens, the maximum rolling shear strength was increased by 129% compared to the control. [ABSTRACT FROM AUTHOR]

Engineered wood products, such as oriented strand board (OSB), are widely used as the primary structural component in both residential and commercial lumber construction, primarily due to their renewability, aesthetic appeal, and excellent mechanical properties. Unfortunately, the inherent flammability of these wood-based composites poses an ongoing risk to society and the environment. In an effort to reduce its flammability, a polyelectrolyte complex (PEC) coating consisting of sodium polyborate (SPB) and polyethylenimine (PEI) was deposited on OSB using a simple two-dip process. This PEC treatment imparts self-extinguishing behavior to OSB and reduces the total heat release by 21% and total smoke release by 79%, while increasing the time to ignition by 18% relative to untreated OSB. Furthermore, the PEI/SPB coating adds little additional weight (5.8 wt%) to the oriented strand board, preserving visual aesthetics and maintaining mechanical properties. The main flame-retardant effect occurs by condensed phase action via a combination of intumescence and thermal barrier mechanisms. Improving the fire protection of OSB and other engineered wood materials through a simple and environmentally benign treatment will increase their potential as a largely renewable building material, promoting a sustainable bioeconomy. [ABSTRACT FROM AUTHOR]

This study investigated the effects of different adhesives, phenol formaldehyde (PF) and melamine urea formaldehyde (MUF), on the mechanical and fire properties of flame-retardant laminated bamboo lumber (LBL). The results demonstrated that the flame-retardant treatment using phosphorus–nitrogen–boron compounds endowed the LBL with excellent flame retardancy and smoke suppression properties, even though the bending strength and bond shear strength were slightly reduced. The PF-glued LBL exhibited superior mechanical and shear properties to the MUF-glued ones, primarily due to its higher processing temperature and deeper adhesive penetration. In addition, the MUF-glued flame-retardant LBL displayed better heat release reduction and smoke suppression properties than the PF-glued LBL, which resulted from the synergistic flame retardancy between the melamine element in MUF and the applied flame retardant. The analysis of the influence of adhesive type on the mechanical and fire properties of flame-retardant LBL holds significant importance for the future design and production of high-performance LBL material. [ABSTRACT FROM AUTHOR]

Experiments were conducted to evaluate the effect of shank diameter, shank type, penetration depth and insertion direction on the nail-holding behaviour of laminated bamboo lumber (LBL). It was found that the shank type of the fastener had a significant effect on the failure mode. Nails, with a smooth shank, were pulled out directly from the LBL without other visible damage. However, when screw fasteners were used, bamboo fibres around the screws were torn. The load–slip curves of the specimens were linear up to the maximum load and the relative slip between the fasteners and the LBL was small at this stage. However, the post-peak performance of both nails and screws varied significantly on the descending portion of the curves. Specimens with nails inserted parallel to the grain showed the smallest nail withdrawal capacity, followed by specimens with nails inserted in the tangential and radial directions. As expected, the withdrawal capacity of the specimens increased linearly with an increase in embedment depth and shank diameter. The experimental load–slip curves were compared with existing theoretical models and the most suitable models to predict the load–slip relationship of the withdrawal behaviour of nails and screws in LBL were identified. [ABSTRACT FROM AUTHOR]

Much of the archaeology and history of labor is based on organized labor, unions, and strikes, and the common rhetoric emphasizes the success or failure of union strike activities. This frames labor activism with clear winners and losers and inadvertently adopts the vantage point of capital. Given the modern world where union membership is plummeting, "success" seems even more unlikely. In this paper, I use the case of the Coalwood lumber camp to argue that labor's "success" was much more complicated than simply winning strikes. Recognizing the difference between concrete and abstract labor provides a way to think about worker's decisions to structure their lives based more on concrete than alienated labor that gives them more autonomy over their lives. [ABSTRACT FROM AUTHOR]

Background: The occurrence of metastases in the vertebral bone marrow is a palliative sign of malignant malignancies. This research aimed to compare the three-field and four-field techniques for 3D conformal radiation. The primary objective was to measure and compare the Conformation Index (CI), the Homogeneity Index (HI), and the Gradient Index (GI), as well as to investigate the radiation dosage absorbed by high-risk organs such as the spinal cord and kidneys. Materials and Methods: Under the supervision of an oncologist, forty patients diagnosed with lumbar vertebral marrow metastasis tumors underwent CT simulation as part of their radiotherapy treatment. The acquired CT scans were then used with the Monaco v5.3 Treatment Planning System to generate delineations and treatment plans (TPS). Elekta's developed agility linear accelerator was used for the administration of radiotherapy. Two plan types were created for comparison: the three-field method and the four-field approach. Results: The statistical analysis of lumber vertebral marrow metastatic tumors using the PTV 95%, PTV 105%, and PTV 2% criteria demonstrates that the four-field approach is better than the three-field technique. The four-field process delivers a higher maximum and means dosage to the tumor volume for PTVs of 95%, 105%, and 2%. However, the two systems have no substantial difference for the 95 percent PTV minimum dosage. These findings imply that the four-field method may be a more successful therapeutic option for individuals with malignancies that have spread to the spinal marrow. More study is required to verify these results and investigate other variables that may impact treatment outcomes. According to the findings of the investigation, the four-field approach was considerably superior to the three-field technique for the Homogeneity Index (HI) and Gradient Index (GI), while there was no significant difference for the Conformity Index (CI). Both approaches adhered to their designs. The research implies that the four-field strategy may be more successful at protecting the spinal cord, whereas the three-field technique protects the kidneys. Conclusion: According to our results, the four-field strategy is more successful than the three-field technique in reducing radiation dosage to the spinal cord. In contrast, the three-field strategy is more successful than the four-field technique for protecting the kidneys. The four-field planning approach is superior for attaining a homogeneous dose distribution in the lumbar spinal bone metastases target volume. [ABSTRACT FROM AUTHOR]

Analyzing the feasibility of reinforcing new and existing wooden structures is a valid problem, being the subject of numerous scientific papers. The paper presents the preliminary results of a study on reinforcing Laminated Veneer Lumber (LVL) panels with composite materials bonded to exterior surfaces using epoxy resin. Glass-Fiber-Reinforced Polymer (GFRP) sheets, Carbon-Fiber-Reinforced Polymer (CFRP) sheets, and Ultra-High-Modulus (UHM) CFRP sheets were used as reinforcement. The variables in the analysis were the type of reinforcement and the number of reinforcement layers. The tests were carried out on small samples (45 × 45 × 900 mm) subjected to the so-called four-point bending test. Reinforcement positively affected the mechanical properties of composite section. The highest increases in load bearing were 37 and 48% for two layers of GFRP and CFRP, respectively. The bending stiffness increased up to 53 and 62% for two layers of CFRP and UHM CFRP, respectively. There was a change in failure mode from cracking in the tension zone for unreinforced beams to veneer shear in the support zone (for CFRP and GFRP sheets) and sheet rupture (UHM CFRP). Good agreement was obtained for estimating bending stiffness with the presented numerical and mathematical model; the relative error was up to 6% for CFRP and GFRP and up to 20% for UHM CFRP. This preliminary study proved the effectiveness of combining LVL with FRP sheets and indicated their weak spots, which should be further analyzed to improve their competitiveness against the traditional structures. The key limitation was the shear strength of LVL. [ABSTRACT FROM AUTHOR]

Lumber recovery is an important parameter in determining the production efficiency and viability of mobile sawmilling operations. In this study, lumber recoveries for mobile sawmilling machines operating in four different locations in Tanzania were estimated. A total of 11 mobile sawmilling operations were studied. On each piece of mobile sawmilling machinery, data on log sizes, including bottom, mid and top diameter, and log lengths were recorded. Results showed that the number of logs per machine ranged from 5 to 40 with an average of 28 logs. The middle diameter of the logs ranged from 8 to 44.60 cm, with an average value of 20.58 cm. The number of lumbers produced for each log varied from 1 to 9 pieces, with an average of 3 pieces across all the sites. The lumber recovery (%), varied depending on the individual machine, machine type, source of logs and geographical site within Tanzania. For all the machines, the average lumber recovery (%) per machinery ranged from 16.15 to 62.79%. Among the three types of mobile sawmilling machinery, Wood-Mizer had relatively higher lumber recovery (56.2%) than Ameck and Ding-Dong. The overall average lumber recovery value for all the machines, irrespective of log sizes, site and source of lumber was 43.34%. Analysis of variance (ANOVA) indicated that site, source of lumber, machine type and size of logs had a statistically significant effect (p < 0.05) on lumber recovery (%). The study concluded that mobile sawmilling in Tanzania produces sawn timber with reasonable lumber recovery. However, further studies are recommended to examine technical aspects, such as productivity and taper, as well as cost of the mobile sawmilling operations. [ABSTRACT FROM AUTHOR]

Mass timber construction is widely considered a promising alternative construction method to reduce buildings' total life-cycle carbon emissions because wood is a carbon sink. Cross-laminated timber (CLT) panels, manufactured by gluing lumber layers with grains at right angles, are potential low-carbon alternatives to carbon-intensive concrete and steel construction. However, most environmental impact assessment studies do not consider variation in transportation impacts within the CLT supply chain when calculating life-cycle impacts. This study investigates the embodied primary energy and the global warming potential (GWP) of CLT supply chain decisions regarding the type of timber species used, the U.S. region it is sourced from, and the location of the CLT mill. Longer transport distances in the supply chain for timber and CLT panels can contribute as much as 923MJ/m2 (20%) of the embodied primary energy of a CLT building, and the use of a higher-density timber species increases this contribution to 1246 MJ/m2 (24%), with most of that energy derived from fossil energy sources. For perspective, the GWP of a building whose CLT panels and timber have been transported by truck over 6,000 km (252-270 kgCO2/m2) is greater than the GWP of an equivalent reinforced concrete (RC) building (245 kgCO2/m2). Thus, factors like the location of CLT processing facilities and the type of timber species can significantly impact the overall life-cycle assessment and, if chosen appropriately, can mitigate the environmental impacts of CLT construction. [ABSTRACT FROM AUTHOR]

This study was part of a larger project investigating the feasibility of using ponderosa pine (Pinus ponderosa, PP) harvested from forest restoration programs in the Northwestern United States for low-rise modular buildings. The panels have a standard width of 1.2 m to consider dimensions available from local manufacturers. To use these panels as walls or floors, they must be joined using in-plane connections. The stiffness and capacity of these connection systems under reversal lateral loading affect the behavior of the multipanel wall systems. Such multipanel systems are proposed for use in modular construction, with the goal of finding suitable market outlets for PP cross-laminated timber (CLT). In-plane connections within the multipanel system here play the role of the intramodular connection, while intermodular connections connect different multipanel systems to form a structure. Butt joints with 45° screws and a bolted point-type connection system were selected as intramodular and intermodular connections, respectively, due to their suitability for prefabrication and ease of installation. The aim of the study was to determine the mechanical characteristics of these two types of connections in PP CLT. Ten intramodular connections under monotonic and cyclic loading in shear and tension, and 12 intermodular connections in monotonic and cyclic in two different configurations were tested. The resulting force-displacement curves were used to extract the mechanical characteristics of the connections, which were then compared to the performance of the same type of connections in CLT panels made from other wood species. The intramodular connection showed high ductility in shear and low to medium ductility in tension, while the intermodular connection had lower initial stiffness compared to tests of commercial CLT in all tested directions except compression. [ABSTRACT FROM AUTHOR]

The study harnesses snail shell and pumpkin pods (wastes) for green productions of materials for biomedical applications. Snail shell and pumpkin pod nanoparticles were produced and incorporated into the high-density polyethylene (HDPE). Nanoparticles and nanocomposites produced were examined. Results indicate that both nanoparticles are relevant medically and fit in as reinforcements for developing materials for biomedical applications. Improvement in the tensile properties, flexural properties, and impact energy values up to a certain percentage by weight of nanoparticles additions was noted with degradation in the fracture toughness and strain energy release rate at all percentages by weight of nanoparticle additions. Since maximum flexural strength was recorded at 4% by weight, properties of HDPE containing 4% by weight of the snail shell nanoparticles and that containing 2% each of the snail shell and pumpkin pod nanoparticles were compared with properties of the reported human cortical and trabecular bones in the literature. It is noted that mechanical properties of both nanocomposites are superior to those of the trabecular bones in the thoracic lumber region but are inferior to those of the cortical femoral bones. Therefore, both nanocomposites are mechanically suitable for biomedical applications as materials for replacing the trabecular bones in the thoracic lumber region. However, they are recommended for compatibility screening to ascertain their biological suitability. [ABSTRACT FROM AUTHOR]

Sustainability has become a key issue in the forest industry; this research aims to analyze the quantitative techniques and metrics applied to the forest-to-lumber supply chain to achieve sustainable decision-making during the last six years. The methodology used was the PRISMA systematic literature review guide, which provides a complete and updated view of the situation. A total of 724 publications were collected from the Web of Science database. Consequently, 85 papers were selected for analysis and synthesis after applying inclusion criteria. The results show a growing interest in sustainability in the forest-to-lumber supply chain, with a peak of publications in 2019. Mathematical Programming and Simulation models are on top of the quantitative techniques applied. These techniques are applied to the supply chain components, classified according to the raw material's degree of processing or transformation level in forest entities, sawmills, transportation, and other entities. The concluding remarks highlighted that 19 published works research the social dimension, 43 explore the environmental dimension, and 55 examine the economic dimension. Moreover, in the environmental dimension, there is a concentration on the use of metrics associated with greenhouse gases, and to a lesser extent, they have been concerned with soil and water. Additionally, in the social dimension, they have concentrated mainly on the workers, leaving the local communities around the supply chain in the second place. Our systematic review reports the techniques or quantitative methodologies applied in the forest-to-lumber supply chain and the metrics used to handle the dimensions of sustainability. [ABSTRACT FROM AUTHOR]

Wood is a commonly used building material with numerous advantages over other construction products. However, in engineered wood products such as cross-laminated-timber and laminated veneer lumber moisture absorption can lead to decay, swelling, deformation, and glue line failures, diminishing their properties. Understanding moisture intrusion processes in these materials can aid manufacturers, engineers, and architects in developing effective moisture management strategies during and after construction. The porosity of CLT 3P sections was 56.5%, higher than CLT 2P sections at 36.8%. True density varied among species, with radiata pine, southern pine, and shining gum measuring 1358, 1411, and 1031 kg/m3, respectively. True density values for CLT 3P, CLT 2P, and LVL were 1202, 837, and 1406 kg/m3, respectively. The species and sample type significantly influenced porosity and density values, crucial for future moisture modelling and predicting moisture gain/loss during wetting and drying processes. Moisture sorption and desorption properties were examined for Australian timber species, CLT, and LVL at different temperatures. LVL samples exhibited higher moisture content and dimensional changes, possibly due to improved moisture transfer facilitated by lathe checks. CLT samples demonstrated greater anisotropic behaviours than those of LVL samples. The product type and sample type had significant effects on equilibrium moisture content values. [ABSTRACT FROM AUTHOR]

The withdrawal resistance of self-tapping screws (STS) in Korean structural softwood in the vertical fiber direction was examined. Four representative softwood species were selected based on their specific gravity. Three STS fastener diameters were used for an STS penetration depth of 50 mm. The withdrawal capacity tended to increase with the specific gravity of the specimens and as the diameter of the STS increased. Primarily, the difference in strength was maximized as the STS diameter increased from 8 to 10 mm. Predictive experimental equations were proposed based on the experimental values of the relationship between the specific gravity of the structural material and the withdrawal resistance according to the diameter of the STS. The values were compared with the predicted values calculated using fastener and screw prediction equations proposed by the National Design Specification for Wood Construction (NDS) and European Standards (EN). The results calculated using the NDS prediction equations yielded a peak difference of 43% compared with the experimental withdrawal capacity, whereas the EN prediction equations yielded a difference of 0.7 to 1.14 times the experimental values. The ratios between the withdrawal capacity predicted by the proposed prediction equations and the experimental withdrawal capacity were the most similar, ranging from 0.80 to 1.15. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the correlation between the mass loss (ML) of wood due to thermal modification and the equilibrium moisture content (EMC) of thermally modified wood. After thermal modification of larch lumber under various temperature and time conditions, ML according to treatment temperature and time was measured, and the (EMC) of the thermally modified wood was evaluated for each treatment condition. As the treatment temperature increased and the treatment time became longer, the ML of wood due to thermal modification increased. In addition, as the treatment temperature increased, the difference in EMC between the non-treated wood and the thermally modified wood tended to increase. Finally, a robust logarithmic correlation was observed between the ML due to thermal modification and the EMC of the thermally modified wood. These results suggest that the EMC of thermally modified wood can be predicted by simply measuring the weight of wood before and after thermal modification. [ABSTRACT FROM AUTHOR]

This study was conducted to confirm the feasibility of using yellow poplar, which is a fast-growing hardwood species in Korea, as a structural material. Lumber was produced, and the mechanical grading and the knot diameter ratio on the wide surface measurement were performed for each grade of lumber. It was confirmed that the majority mechanical grades of yellow poplar were E10, E11, and E12, and the size of knot in the surface increased as the mechanical grades decreased. A fitted distribution of tensile strength of the lumbers was the Weibull distribution. As a result of calculating the tensile allowable stress using the 5th percentile value calculated by the Weibull distribution and the non-parametric method according to the mechanical grade, all the experimental values were higher than the minimum allowable stresses presented in the Korean industrial standards. However, for the low grades, there was no significant difference from the standard values. This was thought to be due to the large size of knots in low-grade lumber. It was expected that the prospect of using yellow poplar structural member will be higher if additional research is conducted on the restriction of knot size according to the mechanical grade. [ABSTRACT FROM AUTHOR]