Fire resistance of wood materials is crucial for the safety and longevity of construction structures, with spruce wood (Picea abies spp.) being widely used due to its mechanical properties. However, its natural fire resistance is limited, which poses a challenge in the context of fire safety. This study investigates the effects of various treatments and additives on enhancing the fire resistance of spruce wood. The methodology includes testing fire resistance using the small flame test in accordance with relevant standards. The expected results could contribute to improving safety standards in the construction industry, enabling broader and safer application of spruce wood in fire-sensitive constructions. Surface roughness analysis revealed significantly smoother surfaces in treated samples (Sa = 9.03 μm) compared to untreated sawn samples (Sa = 84.54 μm), which contributed to reduced combustion intensity. In small flame tests, untreated samples exhibited visible flames with flame heights up to 13.5 cm, whereas Burn Block treated samples showed no flame development and minimal color changes. Interestingly, burning depth was greater on treated samples, reflecting surface carbonization and the formation of a protective intumescent layer that slowed heat transfer and prevented deeper structural damage.

The research aims to improve the durability and functionality of traditional wooden structures through innovative technologies, reducing the ecological footprint and enhancing the economic viability of local materials. The model benches are made from five different types of indigenous conifer wood: Norway spruce, scots pine, larch, thermally modified spruce, and spruce treated with a copper-ethanolamine based biocide. Sensors installed on the benches allow continuous monitoring of wood moisture, a key factor in determining material durability under specific climatic conditions. Collected data will enable the evaluation of optimal wood types for various climatic conditions, promoting the wider use of indigenous, environmentally renewable materials. The project also aims to connect the wood protection industry with end-users, fostering sustainable approaches to environmental preservation, cultural landscapes, and wooden heritage. The research results support the application of wood materials in sectors such as agriculture, maritime transport, and tourism, contributing to ecologically sustainable and economically efficient use of natural resources.

Cutting processes, in general, and wood cutting processes in particular, are complex to explain and describe, depending on a number of influencing factors such as material characteristics, cutting tool geometry and cutting parameters. A thorough understanding of the characteristics of woodworking machining, such as cutting tool wear, cutting forces, energy consumption, and cutting tool stress, gives the opportunity to improve product quality, increase production efficiency, or improve the technological process. In this paper, some characteristic parameters of processing in flat, extensive milling of solid wood of different species are analysed in order to determine the significance of the selected parameters, as well as their mutual influences on the required cutting power.

This study investigates the impact of thermal modification on the water resistance and colour stability of Indigenous wood species from Bosnia and Herzegovina, including Norway spruce (Picea abies), silver fir (Abies alba), oak (Quercus sp.), and walnut (Juglans regia). Thermal modification, conducted in the presence of air, enhanced the hydrophobicity of all tested wood species by reducing their water absorption and limiting their susceptibility to moisture-driven dimensional changes. The modification process also induced notable colour changes, darkening each species in line with the degradation of lignin and other wood constituents. The degree of colour change was observed to increase with higher treatment temperatures, particularly at 210 °C, as measured by the CIE Lab colour system. These findings suggest that thermal modification provides an environmentally friendly method to improve both durability and aesthetic appeal in wood, extending the material’s application range for humid or outdoor environments.

This study investigates innovative surface coatings’ effectiveness in enhancing spruce wood’s fire resistance (Picea abies spp.). Spruce wood samples were treated with various agents, including oils, waxes, boric acid, commercial coatings, and fire-retardant agents. The evaluation was conducted using the small flame method (EN ISO 11925-2:2020), surface roughness analysis, hyperspectral imaging (HSI), and contact angle measurements. The results demonstrated significant improvements in fire resistance for samples treated with specific coatings, particularly the Burn Block spray and Caparol coating, which effectively prevented flame spread. The analysis revealed that the Burn Block spray reduced the average flame height to 6.57 cm, while the Caparol coating achieved a similar effect with an average flame height of 6.95 cm. In contrast, untreated samples exhibited a flame height of 9.34 cm, with boric acid-treated samples reaching up to 12.18 cm. Char depth measurements and the surface roughness analysis revealed a clear correlation between the type of treatment and the thermal stability of the wood. Hyperspectral imaging enabled a detailed visualisation of surface degradation, while contact angle measurements highlighted the impact of hydrophobicity on flammability. This research provides in-depth insights into the fire-retardant mechanisms of spruce wood and offers practical guidelines for developing safer and more sustainable wood materials for the construction industry.

This study investigates the impact of infill density on the mechanical properties of fused deposition modeling (FDM) 3D-printed polylactic acid (PLA) and PLA reinforced with carbon fiber (PLA+CF) specimens, which hold industrial significance due to their applications in industries where mechanical robustness and durability are critical. Exposure to cooling lubricants is particularly relevant for environments where these materials are frequently subjected to cooling fluids, such as manufacturing plants and machine shops. This research aims to explore insights into the mechanical robustness and durability of these materials under realistic operating conditions, including prolonged exposure to cooling lubricants. Tensile tests were performed on PLA and PLA+CF specimens printed with varying infill densities (40%, 60%, 80%, and 100%). The specimens underwent tensile testing before and after exposure to cooling lubricants for 7 and 30 days, respectively. Mechanical properties such as tensile strength, maximum force, strain, and Young’s modulus were measured to evaluate the effects of infill density and lubricant exposure. Higher infill densities significantly increased tensile strength and maximum force for both PLA and PLA+CF specimens. PLA specimens showed an increase in tensile strength from 22.49 MPa at 40% infill density to 45.00 MPa at 100% infill density, representing a 100.09% enhancement. PLA+CF specimens exhibited an increase from 23.09 MPa to 42.54 MPa, marking an 84.27% improvement. After 30 days of lubricant exposure, the tensile strength of PLA specimens decreased by 15.56%, while PLA+CF specimens experienced an 18.60% reduction. Strain values exhibited minor fluctuations, indicating stable elasticity, and Young’s modulus improved significantly with higher infill densities, suggesting enhanced material stiffness. Increasing the infill density of FDM 3D-printed PLA and PLA+CF specimens significantly enhance their mechanical properties, even under prolonged exposure to cooling lubricants. These findings have significant implications for industrial applications, indicating that optimizing infill density can enhance the durability and performance of 3D-printed components. This study offers a robust foundation for further research and practical applications, highlighting the critical role of infill density in enhancing structural integrity and load-bearing capacity.

Wood is one of the most important materials that has been used for several millennia. It is therefore not surprising that wood plays an important role in the cultural and technical heritage of several European countries and beyond. An excellent example of cultural and technical heritage is a wooden mill, almost 100-year-old, near Cazin in Bosnia and Herzegovina. These mills played an important role, especially in times of Bosnian war (1992- 95), when this region was cut off from electricity. The microscopic analysis of the wood materials used in the mills revealed that the mills were made of chestnut (Castanea sativa) and oak (Quercus sp.) wood. Sufficient durability of these wood species resulted in good structural integrity of the mills. The surface of the wood materials in the mills showed partial degradation patterns caused by weathering over the years. However, the interior parts of the wood materials were intact probably due to smoke deposits from the open fireplace. It is suggested that the roofing in the mills should be maintained regularly to prevent possible leaks to protect this heritage for future generations.

The paper describes the factorial design of the experiment with three input factors that change on two levels. For given values of the input parameters, it is shown how to obtain a variance analysis table and which factors and interactions between factors are significant. The example was done in the software intended for the design of the experiment and in the software R. It is shown how to use the software R to arrive at the final solution of the given example.

The aim of this study was to investigate the mechanical behavior of beech and fir finger joints under laboratory conditions. The samples were manufactured using a 9 mm finger joint with glued surfaces, in accordance with the EN 14 080 standard. Polyurethane adhesive of class D3, commonly used for the production of exterior wooden structures in Bosnia and Herzegovina, was applied to the samples. The specimens were subjected to destructive four-point bending tests according to the BAS EN 408 standard, and the achieved bending strength was statistically evaluated and compared to the results of unglued samples.