The aim of this paper was to analyze selected properties of beech wood (Fagus sylvatica L.) treated by one-sided surface charring. Specimens were one-side charred with a hot plate using several time-temperature combinations (from 200 to 400 °C). Characteristics such as colour, discoloration, surface roughness, fire resistance, total carbohydrate content at several wood layers and decay resistance were evaluated. Surface charring was applied to the radial and tangential surfaces. Colour measurements showed that the surface of the wood turned grey due to charring. In addition to colour measurements, other experiments showed significant differences between radial and tangential specimens due to their different structures. The higher the temperature used in treating them, the lower the roughness values for radial specimens, while the trend for tangential specimens was the opposite. A smoother surface is more fire resistant, so radial specimens are generally better in this regard. Tangential specimens are more susceptible during preparation to forming cracks that impair flame resistance because a continuous protective densified layer is not formed. The determination of total carbohydrates revealed significant changes at various wood depths after surface charring. These changes were more predictable in radial specimens due to the annual ring orientation, because each layer consisted of a similar earlywood/latewood ratio. Finally, when decay resistance was assessed, weight loss was found to be lower in all specimens than in the references. The results suggest that charring at a particular combination of temperature and time improved the investigated properties of the surface-modified beech.

The European Union’s Green Deal emphasises the importance of improving the efficiency of the energy sector in its countries, which is why the issues involved are relevant in both scientific and practical terms. The article sets out the hypothesis that conveying the state of the economic efficiency of energy development by grades does not reflect the real situation. Instead of ranks, it is proposed to form homogeneous groups of some countries based on non-linear data normalisation instead of today’s universally used linearisation. Grouping the euro area countries in the European Union on the basis of the value of the cost-effectiveness indicator for the energy development of their industrial sector confirmed the appropriateness of the proposed method-ology. In this way, three groups of countries were formed according to the level of cost-effectiveness achieved. The proposed methodology for grouping countries is universal and can be used for international comparisons of any kind.

In order to describe the behaviour of wood when calculating wooden elements and structures with the use of the finite element method, orthotropic material model in combination with non-interactive (maximum stress criterion) or interactive failure criteria (Hoffman and Tsai-Wu criterion) is used. Another option is to use a general anisotropic plasticity material model complemented with a non-interactive failure criterion – maximum stress criterion, which allows to describe wood failure by brittle failure in tension. The presented general material model was used in combination with the idealization of annual rings by cylindrical surface for the modelling of wood specimen tests form Scots pine (Pinus sylvestris). The obtained results show good agreement between the results of numerical analysis and experimental testing of wood specimens. The use of the anisotropic material model can also be seen in cases when the level of the applied load is higher than the level when the failure of wooden material occurs.Radi objašnjenja ponašanja drva pri proračunima drvnih elemenata i konstrukcija primjenom metode konačnih elemenata, upotrijebljen je model ortotropnog materijala u kombinaciji s neinteraktivnim kriterijem (kriterij maksimalnog naprezanja) ili interaktivnim kriterijima loma (Hoffmanov i Tsai-wuov kriterij). Druga je mogućnost upotrijebiti opći model za anizotropno-plastične materijale dopunjen neinteraktivnim kriterijem loma – kriterijem maksimalnog naprezanja, koji omogućuje objašnjenje lomljivosti drva pri naprezanju. Predstavljeni opći model materijala u kombinaciji s idealizacijom godova kao cilindričnih površina upotrijebljen je za modeliranje uzoraka izrađenih od drva običnog bora (Pinus sylvestris). Dobiveni rezultati pokazuju dobru podudarnost rezultata numeričke analize i rezultata eksperimentalnih ispitivanja uzoraka drva. Model anizotropnog materijala primjenjiv je i kada je opterećenje veće od onoga pri kojemu dolazi do loma drvnog materijala

The indoor environment that surrounds us and the elements in it affect not only our mood but also the air quality. Vegetation elements are currently more popular, especially for their aesthetic value but also because of the fact that they affect the physical parameters of the indoor environment such as temperature and humidity. Water elements are a similar example. The presented paper combines these two elements to achieve the best possible level of thermal comfort. Experimental verification of the influence of the living wall on air temperature and humidity took place during the heating season in the city of Brno in the space of the university, while three scenarios were created: the effect of the living wall in a semi-open space, an enclosed space, and a space with a water wall with regulated water temperature. The potential of the water wall is determined based on experimental verification in laboratory conditions. The results show that the synergy of the living and water wall in the indoor space may eliminate the risk of too-low humidity during the heating season.

The aim of this work was to verify the behavior of hybrid hardwood glue-laminated beams and the possibility of replacing Norway spruce (Picea abies) construction elements, especially in roof and ceiling structures. The samples were six lamellae homogeneous beech (Fagus sylvatica) beams and six-lamellae hybrid beech-poplar (Fagus sylvatica–Poplar spp.) beams; each beam had a cross-section of 60 × 120 mm and was glued with polyurethane adhesive. The samples were loaded using destructive four-point bending tests according to EN 408; the obtained bending strength and modulus of elasticity were statistically evaluated and compared to each other in both types of samples. The results showed that the examined properties of the hybrid beams (with a 16% weight reduction) are comparable to the properties of homogeneous beech glue-laminated beams. Based on the obtained data, the timber elements that are currently used can be successfully replaced by hardwood glue-laminated elements. Based on their higher load-bearing capacity, the cross-section depth can be reduced compared to a larger cross-section depth in spruce beams; this means that hardwood could be suitable in building renovations.

With the sustainable construction the emphasis is placed on saving energy, reducing of consumption of natural resources, extending the life cycle of recycling, etc. One of the important groups of waste materials that can be reused are waste polymers. These materials are used in the design of thermal insulation composite material. The crucial property of materials used for thermal insulation is the coefficient of thermal conductivity. Thermal conductivity coefficients of waste polymers however do not meet the requirements. For this reason, waste polymers are within the development of thermal insulation composite material combined with filler with a low coefficient of thermal conductivity. In developing of this composite material the developers combine a method of theoretically optimized software design of blends with their production and experimental verification. Possibility of application of thermal insulation composite material can be seen especially in the structural details, in which it is necessary to eliminate the thermal bridges, but also details where the requirements are applied to the mechanical resistance and static load bearing capacity.