Types Of Wood Research Articles

Comparison and parametric study of characteristics of eleven types of anisotropic woods based on the behaviour of Lamb wave propagation

AbstractKnowledge in advance of the nine orthotropic independent elastic constants (Cij) of the wood medium is essential for evaluating its mechanical properties. The most prominent technique to retrieve Cij is the ultrasonic testing technique. This technique uses guided waves that can propagate through the material under test. Accordingly, it is worth noting that the numerical modelling of the phase and group velocities of guided waves is an unavoidable preliminary step before experimentally producing guided wave modes. Therefore, the main goal of the present work is to numerically calculate the phase velocity, group velocity and the relevant optimal incidence angles of Lamb waves in anisotropic wood that can be used as a numerical parametric study for any future experimental setup. Here, Lamb dispersion curves are calculated for eleven types of woods, where the Legendre polynomial method is employed to solve the wave equations. Moreover, the optimal incidence angle for each Lamb mode is calculated according to the Snell–Descartes law. By calculating out the three parameters of phase velocity, group velocity and optimal incidence angle of Lamb modes in eleven types of anisotropic woods, we hope to fast-track the researchers in considering the present work to facilitate their experimental measurements.

OPTIMIZING CHARCOAL PRODUCTION: A COMPARISON OF THREE WOOD SPECIES AND METHODS

For sustainable forestry management and environmental protection, it is crucial to compare three wood types and processes in order to optimise charcoal production. The purpose of this study was to evaluate the viability of using diverse waste materials and carbonization techniques to produce wood charcoal. The upcountry wet zone and low-country dry zone regions of Sri Lanka provided the samples, which were each repeated ten times and came in three different sample sizes. To make charcoal, these samples were put through the barrel and pit processes. The results showed that the barrel method produced 28% charcoal instead of the 21% produced by the pit method, demonstrating its higher efficiency and cost-effectiveness. This improvement was ascribed to the barrel's enhanced ability to regulate airflow and temperature during pyrolysis. The study emphasizes the use of wood off-cuts and the barrel method to increase efficiency, save costs, and improve charcoal quality. It provides helpful advice for small charcoal producers.

Comparative analysis of Environmental Impact of Each Building Material using Life Cycle assessment(LCA)_Focusing on Types of Construction Wood and Concrete

Objectives:The construction sector is a very important sector in achieving carbon neutrality. In modern society, construction has grown rapidly, and basic materials such as cement and concrete have contributed greatly to the development of construction. These materials emit a large amount of global warming substances during the raw material extraction and production process, causing serious environmental pollution. In order to establish a carbon reduction strategy to slow down global warming, we compared the environmental impacts of each building material and showed the current situation.Methods:The LCI DB for the construction materials used in the two-story wooden house (Building area 128.67m2, total floor area 235.73m2) located in the National Institute of Forest Science was extracted. Then, the data for LCA was processed and performed through the life cycle assessment methodology for the resources consumed from raw material collection, material production, and transportation stages. Then, based on the environmental performance labeling impact assessment method, a study was conducted on the environmental impact categories of the actual construction materials used and comparisons with other construction materials.Results and Discussion:When analyzing the environmental impact of concrete [25-21-120] and construction wood used in wooden house, the environmental impact was found to be 98.79% higher on average in the pre-manufacturing stage than in the manufacturing stage, and construction wood was confirmed to have a reduction effect of 62.21 kg CO2-eq per 1 m3 compared to concrete. Through the scenario, there was a carbon reduction effect of up to 36% when the entire area was replaced with wood. In addition, the environmental impact by major construction material was quantitatively quantified.Conclusion:When building a wooden house, reducing the amount of concrete equivalent to the amount of wood is expected to have a greenhouse gas reduction effect, so it is time to activate construction wood from the production process to the post-production stage to replace concrete. In addition, follow-up research on the development of construction technology with low environmental impact during construction should be continued. This study is expected to be used as a useful indicator for R&D and policies in the construction field in the future, as it quantitatively quantified the amount of CO2 reduction per m3 when replacing concrete with construction wood and numerically compared and analyzed six major environmental impact categories by major construction materials.

Tribological properties and related effects of compressed, thermally modified and wax-impregnated wood

AbstractThis paper develops a process for the preparation of modified wood with low friction and low wear for tribological applications such as self-lubricating bearings. Two types of wood, beech (Fagus sylvatica) and robinia (Robinia pseudoacacia), have been studied and the results compared with naturally lubricated native lignum vitae. The process developed consists of plasticisation followed by compression in a mould, thermal modification and subsequent wax impregnation. Plasticisation was carried out by conditioning the samples to a low equilibrium moisture content of 10%, followed by heating to a sample core temperature of 80 °C. This process protects the internal wood structure from mechanical damage during densification. After plasticisation, the wood was compressed in a press mould. A low springback effect (SBE), resulting in compression of up to 40%, was achieved by unloading the mould without opening it. This step optimises compressive strength and hardness. Subsequent heat treatment reduces thickness swelling by up to 85%. Finally, a wax impregnation was applied to reduce friction. Sliding wear tests on modified beech wood have shown that the lowest wear occurs in the cross-sectional orientation (load perpendicular to the fibre ends; rxt orientation). Sliding friction studies using a steel ball on a ball-on-disc tribometer showed that compressed and thermally modified samples impregnated with rapeseed wax or beeswax exhibited coefficients of friction in a range of 0.08 to 0.09. These values are almost four times lower than those of plain compressed wood and even lower than those of lignum vitae, which was used for plain bearings decades ago. This study clearly demonstrates the high potential of compressed, thermally modified and wax-impregnated wood.

Evaluations of the deterioration characteristics of thermally treated wood samples from Corymbia citriodora and Eucalyptus urophylla caused by marine wood borers

The low natural durability properties of some types of wood indicate the need for treatments to enhance the resistance of these materials to biological decay. In the sea, this resistance is necessary due to the actions of wood-boring mollusks and crustaceans. These treatments must be effective without harming the environment. Wood thermal treatment should be evaluated for this purpose. Therefore, the aim of this study was to evaluate the deterioration characteristics of thermally treated wood samples from Corymbia citriodora and Eucalyptus urophylla under the actions of marine wood borers. A method was proposed to aid in this assessment. Ten samples of these woods, both untreated and thermally treated, were submerged in the sea, each at a depth of 2.5 meters, for five months. After this period, the external borehole number, mass loss, and central flat lesion parameters of the samples were evaluated. Both the thermally treated and untreated wood samples of C. citriodora showed less deterioration than those of E. urophylla, with fewer boreholes, smaller lesioned areas, and lower mass losses. Compared with untreated wood and E. urophylla wood, thermally treated C. citriodora wood exhibited some resistance to marine wood borers. It was concluded that C. citriodora wood was naturally more resistant to marine wood borers than E. urophylla wood. Moreover, thermal treatment increased the boring resistance of C. citriodora wood while increasing the susceptibility of E. urophylla wood. The digital measurement of flat lesions was proven to be an auxiliary and promising method for evaluating the deterioration process.

Assessment of surface roughness in milling of wood with different material temperature and cutting parameters

Effects of wood temperature were studied during CNC router processing relative to the resulting surface roughness, addressing a considerable gap in wood machining research. Three wood species (Scots pine, beech, and poplar) were machined at four temperatures (-20 °C, 0 °C, 20 °C, and 50 °C) to simulate diverse climatic conditions. The experiments were conducted at varied spindle speeds (6000, 12000, and 18000 rpm) and feed rates (3000 and 6000 mm/min). Surface roughness was measured using a portable tester in accordance with relevant ISO standards. A full factorial design was used to evaluate the effects of wood species, temperature, spindle speed, and feed rate on surface roughness. Results revealed a strong correlation between processing temperature and surface roughness, with a 25.9% increase in roughness observed as temperature rose from -20 °C to 50 °C. This temperature effect was consistent across all wood species, though its magnitude varied. The study also found that wood type, spindle speed, and feed rate significantly influenced surface quality, interacting with temperature effects. These findings suggest that controlling wood temperature during processing could be crucial for maintaining consistent surface quality in industrial applications, especially in facilities operating under variable environmental conditions.

Assessment of wood quality for Sape making: Vibroacoustic analysis and machine learning classification

Sape is a popular traditional musical instrument from Sarawak, Malaysia. This instrument is handmade and differs in wood, dimension, design, etc. This impedes the preservation and promotion of the Sape tradition, as well as the development of new Sape instruments. Wood is the primary factor affecting Sape sound, and this study aimed to evaluate the quality of three commonly used types of wood in the instrument manufacturing. Rectangular wood samples were fashioned and tested for physical, vibroacoustic, and timbre characteristics using a flexural vibration test. The objective was to identify the top features influencing the sound quality and develop a reliable method for classifying wood quality. Results showed that Adau wood had the highest quality, followed by Merbau and Tapang wood. Four key features, including acoustic radiation damping coefficient, spectral flux, spectral centroid, and inharmonicity, were selected by the MRMR algorithm and used to train and test various classifiers in MATLAB. The decision tree classifier achieved 98.1% accuracy in predicting wood quality. This study demonstrates the potential of using machine learning to classify Sape wood quality and provides a useful guide for its production. The findings could contribute to the preservation and advancement of this cultural tradition.

Результаты исследования взаимосвязи вязкости и механической прочности беленой лиственной сульфатной целлюлозы

An assessment has been made of the relationship between viscosity and mechanical strength of industrial samples of bleached hardwood kraft pulp. To produce this type of semi-finished product, birch and aspen wood has been used, which has been harvested in the Northwestern region of the Russian Federation. The viscosity of a solution of high-molecular polymers provides an idea of the average length of the fibers and, accordingly, their degree of destruction. In turn, the mechanical properties of the fibrous semi-finished product and the strength of the products made from it largely depend on the length of the fiber. Since it takes no more than 2 hours to determine the viscosity of a solution of high-molecular polymers, and 8–10 hours to obtain standard mechanical strength characteristics, viscosity analysis can be considered an express method that provides information on the mechanical strength of a semi-finished product. In this work, the ISO 5351:2010 international standard in cupriethylenediamine solution has been used to analyze the viscosity of the semi-finished product. High values of mechanical strength characteristics have been detected for industrial samples of bleached hardwood kraft pulp with a viscosity of more than 800 ml/g. For pulp samples, a correlation has been established only between the number of double folds and viscosity. Further research has been carried out on samples of bleached hardwood kraft pulp with different degrees of fiber destruction, which have been produced with varying the parameters of sodium hypochlorite treatment. The results have made it possible to establish a range of critical viscosity values for bleached hardwood kraft pulp, which has amounted to 600...700 ml/g, and a polynomial relationship between tear resistance, breaking length, a number of double folds and viscosity with a high confidence coefficient of data approximation of no less than 0.89. It has been shown that viscosity can become an analytical tool in the express diagnostics of the mechanical strength of a fibrous semi-finished product at the intermediate stages of production of bleached hardwood kraft pulp and in quality control of the ready-made semi-finished product.

A Review on the Effect of Wood Surface Modification on Paint Film Adhesion Properties

Wood surface treatment aims to improve or reduce the surface activity of wood by physical treatment, chemical treatment, biological activation treatment or other methods to achieve the purpose of surface modification. After wood surface modification, the paint film adhesion performance, gluing performance, surface wettability, surface free energy and surface visual properties would be affected. This article aims to explore the effects of different modification methods on the adhesion of wood coating films. Modification of the wood surface significantly improves the adhesion properties of the paint film, thereby extending the service life of the coating. Research showed that physical external force modification improved the hydrophilicity and wettability of wood by changing its surface structure and texture, thus enhancing the adhesion of the coating. Additionally, high-temperature heat treatment modification reduced the risk of coating cracking and peeling by eliminating stress and moisture within the wood. Chemical impregnation modification utilized the different properties of organic and inorganic substances to improve the stability and durability of wood. Organic impregnation effectively filled the wood cell wall and increased its density, while inorganic impregnation enhanced the adhesion of the coating by forming stable chemical bonds. Composite modification methods combined the advantages of the above technologies and significantly improved the comprehensive properties of wood through multiple modification treatments, showing superior adhesion and durability. Comprehensive analysis indicated that selecting the appropriate modification method was key for different wood types and application environments.

Seasonal changes in hydraulic functions of eight temperate tree species: divergent responses to freeze-thaw cycles in spring and autumn.

Freeze-thaw cycles (FTCs) are the major seasonal environment stress in the temperate and boreal forests, which induces hydraulic dysfunction and limits tree growth and distribution. There are two types of FTCs in the field: FTCs with increasing temperature from winter to spring (spring FTCs); and FTCs with decreasing temperature from autumn to winter (autumn FTCs). While previous studies have evaluated the hydraulic function during the growing season, its seasonal changes and how it adapts to different types of FTCs remain unverified. To fill this knowledge gap, the eight tree species from three wood types (ring- and diffuse-porous, tracheid) were selected in a temperate forest undergoing seasonal FTCs. We measured the branch hydraulic traits in spring, summer, autumn, and early, middle, and late winter. Ring-porous trees always showed low native hydraulic conductance (Kbranch), and high percentage loss of maximum Kbranch (PLCB) and water potential that loss of 50% maximum Kbranch (P50B) in non-growing seasons (except summer). Kbranch decreased, and PLCB and P50B increased in diffuse-porous trees after several spring FTCs. In tracheid trees, Kbranch decreased after spring FTCs while the P50B did not change. All sampled trees gradually recovered their hydraulic functions from spring to summer. Kbranch, PLCB, and P50B of diffuse-porous and tracheid trees were relatively constant after autumn FTCs, indicating almost no effect of autumn FTCs on hydraulic functions. These results suggested that hydraulic functions of temperate trees showed significant seasonal changes, and spring FTCs induced more hydraulic damage (except ring-porous trees) than autumn FTCs, which should be determined by the number of FTCs and trees' vitality before FTCs. These findings advance our understanding of seasonal changes in hydraulic functions and how they cope with different types of freeze-thaw cycles in temperate forests.

Measurement and Validation of Market Power in China’s Log Import Trade—Empirical Analysis Based on PTM Model and AIDS Model

China is the world’s largest importer of logs, possessing the scale to exert significant influence in the international market. This paper uses a fixed-effect variable coefficient Pricing-to-Market panel model to measure China’s market power in log import trade. It also utilizes the Almost Ideal Demand System model from an elasticity perspective to explore the market behavior characteristics of various source countries in China’s log import trade, thereby validating the mechanism of market power. The results indicate that: ① China’s main trading partners can be categorized into four groups according to their market power in the log import trade. Specifically, China holds superlative market power in log imports from Indonesia, Malaysia, and Myanmar; holds strong market power in log imports from Russia, the Democratic Republic of the Congo, and Mozambique; holds weak market power in log imports from Papua New Guinea, Equatorial Guinea, France, Germany, Australia, and New Zealand; and holds no market power in Japan, Cameroon, and the United States. ② As China’s expenditure on log imports increases, there is a tendency to purchase high-quality precious wood and a greater concern for the legality of market transactions. Consequently, China is anticipated to augment its imports from source countries with no or weak market power. ③ The simple price elasticity of log imports from each source country is negative. Source countries with stronger market power tend to increase prices to achieve higher total revenue, while those with weaker market power are more inclined to lower prices to achieve the same. ④ Log products from various source countries are complementary in the Chinese market, indicating that China’s substantial demand for logs relies on the simultaneous supply from multiple countries and diverse wood types. Based on the existence or absence of market power in China’s log import trade, this paper provides targeted insights into enhancing international market power and reducing trade losses.

Characteristics of bast fibers derived from the bark of three paper-mulberry cultivars in Korea

Bast fiber from paper-mulberry (Broussonetia papyrifera) has long been utilized for handmade paper in Asia, serving as a prominent non-wood cellulose material. When restoring paper cultural assets, selecting a similar paper to the original ensures longevity and prevents deterioration issues like warping or tearing. The production of handmade paper involves several processes, including refining, steaming, and bleaching of raw materials. Once formed into sheets, the physical properties of the paper are dictated by these materials and remain unchanged unless the paper is newly made. Handmade paper production is labor-intensive and time-consuming, emphasizing the need for careful raw material selection to match desired characteristics. This study evaluated the dendrological, morphological, anatomical, and chemical compositions of three paper-mulberry wood types cultivated in Korea and inferred their suitability as pulp for papermaking or repair of archival paper specimens. Paper-mulberry wood showed differences in fiber length according to molecular phylogenetic characteristics, but there were no differences in anatomical characteristics owing to the immaturity of the wood. This study investigated the characteristics of the bast fibers from the bark of paper-mulberry trees with different genetic traits to identify favorable factors likely to affect the pulp and papermaking process and paper quality.

Exploring the distribution pattern of native and alien forests and their woody species diversity in a small Mediterranean city

Recent studies have explored the ecological relationship between native urban forests and self-sown non-native forests in large cities and metropolises but further research efforts dedicated to analyzing this relationship in small cities are still needed. To improve our understanding of the ecology of urban native and alien forests in Mediterranean small cities, we analyzed the woody species richness, the community-weight mean of moisture and nitrogen ecological indicators, and soil disturbance indicators in the main urban wood types of the city of Campobasso (Italy), as well as their spatial distribution pattern across a gradient of cover and aggregation of green areas. The study showed that both native oak forests and Robinia pseudoacacia forests contributed to the maintenance of woody species richness. If we exclude the riparian environment, R. pseudoacacia forests occupied small marginal patches, tolerating soil disturbance and a high disturbance frequency, thus occupying habitats where the native oak forests could not grow. Conversely, R. pseudoacacia forests shared the ecological niche with the native riparian forests, which calls for action to prevent the spread of this alien species along river banks. Our results highlighted that urban remnant forests should be considered important assets for the planning and upkeep of urban green areas.

Resolving complexity: Material flow analysis of a national wood flow system integrating the versatility of wood

AbstractA systemic understanding of the use of wood resources is required to defossilize society and promote bio‐based developments. This study provides a novel approach to represent a comprehensive material flow analysis (MFA) spanning the entire wood value chain; encompassing wood harvest to products, use in society, collection, reuse, recycle, energy generation, and trade. By recognizing wood as a complex material, with changing properties throughout its lifespan, we developed a method where we employed a color‐coded system for processes (27 boxes) and 110 flows to symbolize distinct life stages and the dynamic characteristics, including 23 different trade flows. The wood processes and flows are categorized (11 categories) into different wood types (e.g., softwood and hardwood) and harmonized to include all available data on each single step of the wood life cycle, improving data traceability and visualization, and allowing for replicable analysis with respective data noted for each process and flow. Methodological obstacles due to different units, uncertainty of flows, and discrepancies in data are addressed and adjustments proposed. Switzerland was chosen as a case study as a large number of various types of data were available to perform the analysis. The categorized and harmonized flows of woody biomass mapped and analyzed in the MFA provide a comprehensive basis to identify and recommend avenues to increase cascading use of wood as a carbon sink, by considering relevant aspects like the network of flows and processes, the quality and availability of the woody biomass, and the organization of the industry.

Characterization of Intsia spp. from Indonesia using microsatellite markers

Microsatellite DNA markers are known to have a high level of genetic diversity and can be used for various purposes. These include population genetic analysis, gene flow assessment, pollen distribution, parent analysis, and accurate distinction between types and varieties. Despite the potential application of microsatellite markers, their development process often requires high costs, energy, and time. To overcome the limitations, several studies have proposed the use of cross-species amplification, which has proven to be a cost and time-efficient method for obtaining species-specific DNA markers. Therefore, this study aimed to identify three species of Merbau in Indonesia, namely Intsia bijuga, I. palembanica, and I. acuminata using cross-species amplification. The three species are known to exhibit similarities in all taxonomical characteristics except for minor differences in the number of leaf pairs per twig and the tip shape of the leaflets. These species also have different levels of economic value and conservation status due to variations in the type of wood produced. Several studies have shown that identification errors can affect the economic value of their wood and logging mistakes can lead to a decrease in the genetic diversity. To address the concerns, Intsia bijuga and I. acuminata from Indonesia were selected as test samples for the cross-amplification of microsatellite markers created for I. palembanica. Due to their taxonomical similarities, the diagnostic characteristics of each Intsia species were assessed based on microsatellite markers. Leaf samples were obtained from three species of Intsia that had been verified and identified based on morphological characteristics by taxonomists from the Bogor Botanical Garden Indonesia. In addition, a total of 10 polymorphic I. palembanica microsatellite markers from the previous literature were used in this study. The results showed that the cross-species amplification of microsatellite locus was successful in all markers. Certain alleles were also observed to be shared by the three species of Intsia, while some were specific to a particular species. These specific alleles could also serve as a diagnostics characteristic for Intsia spp. In addition, a set of polymorphic microsatellites showing a successful transfer across species of Intsia could serve as a valuable tool for comparative studies among related taxa species and breeding and conservation programs.

Mechanical Properties and Flammability Analysis of Wood Fiber Filled Polylactic Acid (PLA) Composites Using Additive Manufacturing

ABSTRACT Natural fibers, such as wood fibers, can substitute for synthetic fibers in various applications due to their low environmental impact, cost-effectiveness, and outstanding mechanical properties as rapid-growing materials and renewable resources. This paper aims to investigate the mechanical properties of 20% wood fiber as a reinforcement material in polylactic acid (PLA) using an additive manufacturing approach. The samples were fabricated using 3D printing techniques. The relevant parameters included the orientation of printing in X, Y, and Z directions, with the percentage of infill set to be 100%. The findings indicated that bio-composites and their adopted printing orientations confirmed the significant effects on the mechanical properties. Pure PLA possessed superior properties in all directions compared to wood/PLA. The highest values were 50.33 MPa for tensile strength and 94.36 MPa for flexural strength, both achieved in Y orientations. However, composites showed an improvement in tensile and flexural moduli in X orientation with 1395.40 MPa, and 2937.72 MPa for Young and flexural modulus, respectively. In the flammability test, wood/PLA bio-composites were ignited easily with reduced smoke production compared to the neat PLA. Wood/PLA bio-composites exhibited high stiffness, and their mechanical properties were influenced by many factors, such as percentage of weight fraction, wood type, and printing orientations.

Characteristics of Mould Growth in Pine and Spruce Sapwood and Heartwood under Fluctuating Humidity

The importance of maintaining a healthy indoor climate has recently increased, as has the durability of building structures, and for this issue, we need to predict mould growth. To prepare this model under real conditions is challenging, and this work aimed to contribute data to this model. This article presents the findings of a laboratory study investigating the effects of fluctuations in the relative humidity and temperature conditions on mould growth on pine and spruce. The study compared the results to a previous steady-state experiment, demonstrating that fluctuations in relative humidity and temperature prolonged the onset of mould growth. The mould growth observed depended on the type of wood with pine or spruce wood exhibiting different growth patterns compared to heartwood or sapwood. In sapwood, mould growth was found to be almost independent of the direction of the fiber. The first microscopic indications of mould growth on pine sapwood were observed around day 76, with the first macroscopic indications observed around day 90. On the contrary, spruce sapwood demonstrated a limit for mould growth. The mould growth was only visible under the microscope with the first indications observed between the 72nd and 80th day. Furthermore, heartwood was found to be unsuitable for mould growth under fluctuating conditions.

Study of the influence of fire retardants on the flammability of building materials made of pine and aspen wood

The results of the study of the effect of industrial fireproofing compositions on the weight loss of samples of solid pine and aspen wood during combustion are presented. Fireproofing compositions of different brands was introduced in the form of ready-made solutions (with a consumption of 500–600 g/m2) by impregnation of test samples of coniferous and deciduous wood. It has been established that, from the point of view of mass loss during combustion fireproofing compositions have different efficiency: the best of them provided I group of fire retardant efficiency. For a comparative assessment of the effectiveness of the use of various industrial flame retardants, the method of analysis of variance was used. The hypothesis about the effect of interaction between the type of wood and the grade of OS was tested, and the significance of the influence of factors on the weight loss of samples during combustion was assessed. It has been established that the effect of interaction between the type of wood and the type of fire retardant composition is 3.51 times greater than the effect of the type of wood, which is due to both the structural differences between aspen and pine wood, and the unequal absorption of OS of different operating principles into the outer layers of the wood material. It was determined that the degree of influence of the type of wood (aspen, pine) on the loss of mass of wood material during combustion is 62.3 times less than the influence of the type of fire retardant composition.

Effect of the mechanical densification process in wood material on the surface adhesion strength of varnishes

This research aimed to determine the impact of the mechanical densifying process of wood material on the varnish surface adhesion strength. Specimens from black pine (Pinus nigra) and Uludag fir (Abies bornmuelleriana Mattf.) were subjected to densification in a hydraulic press at 140 °C to the extent of 25% and 50% in the radial direction. While densification increased the surface adhesion strength of the varnish layer in black pine, the value decreased in fir. Regarding the interaction between densification ratio, surface treatment, and wood type, the highest surface adhesion strength of the varnish layer was found in black pine + unsanded surface + 25% densification, and the lowest was in Uludag fir + unsanded surface + 50% densification. It can be stated that the densification process creates high adhesion values for the polyurethane varnish in the black pine wood type. The sanding process has an intensifying effect on these values, and the products that were obtained from the polyurethane varnished samples do not require sanding. Considering these situations can provide significant advantages in projects with wood materials subjected to the densification process.

Burma Padauk Timber Column Strengthening with Typical Box Built-Up under Compression-Parallel-to-Grain Load

This study investigated and presented the results of strengthening short stub columns made from Burma Padauk timber using three different timber sizes and three distinct timber types. The strengthening method employed a typical box-built-up configuration, where four equal-sized timbers were adhered to all four surfaces of the column. A total of 12 short stub columns were tested under compression-parallel-to-grain loading. Compressive strength was measured at a 0.05% strain offset, and the failure modes observed in all specimens were documented and analyzed. Interestingly, the compressive load capacity was not significantly affected by the three wood types (Burma Padauk, Tabek, and Teak) representing hardwood, medium hardwood, and softwood, when the total cross-section area remained constant. However, an increase in the total cross-sectional area of the strengthening did lead to a noticeable increase in the compressive load capacity. The observed failure modes were crushing for Burma Padauk and Tabek timbers, while the strengthened softwood timber (Teak) exhibited a combination of crushing with wedge splitting and crushing with compression and shearing parallel to the grain.