Search Results (125)

Hericium erinaceus is a fungus that, in addition to its health-promoting properties (including regenerative properties for gastrointestinal membranes and support for neuronal regeneration in neurodegenerative diseases such as Parkinson’s disease), has the ability to synthesize valuable metabolites, such as flavonoids (polyphenols) and terpenoids. These compounds possess strong biocidal properties. These substances provide the growing H. erinaceus mycelium with protection against colonization by other species of rot fungi, such as Trametes versicolor. For these reasons, the biological compounds produced by H. erinaceus can be used to produce ecological fungicides, which will find innovative applications in protecting forest tree seedlings. It should also be emphasized that valuable fungal substances are synthesized primarily by the mycelium of H. erinaceus during the initial stages of its development. Therefore, we undertook to develop an updated and modernized methodology for cultivating H. erinaceus mycelium in the laboratory, with the goal of commercializing the production of this mycelium, which will be used to isolate fungicidal substances metabolized by the fungus cultures. The biocidal substances obtained will be used to produce innovative fungicides in order to protect forest tree seedlings. The studies were conducted using various types of nutrient media, including Potato Dextrose Agar (PDA), Malt Extract Agar (MEA), and wort medium, at various temperatures ranging from 15 °C to 25 °C. Simultaneously, experiments were conducted using solidified media with a pH ranging from 4.0 to 7.0. The research was also expanded to include the growth and execution of experiments using a processed wood substrate, namely, sawdust made from individual structural wood elements. The sawdust was prepared from the bark, sapwood, and heartwood of sessile oak. The PDA medium was more favourable to the mycelium growth of H. erinaceus at 25 °C. It was also found that an acidic pH in the range of 4.0–5.0 significantly influenced the changes in the growth rate of the mycelium species and their phenotype. It was observed that mycelial growth on a substrate of oak sawdust made from sapwood resulted in intensive mycelial growth and a significant reduction in the wood substrate compared to sawdust made from bark, heartwood, and a mixture of all types of sawdust. The reason for the low mycelial growth, low mass reduction and slight reduction in the mass of sawdust made from bark, heartwood, and a mixture of all types of sawdust was the presence of high levels of tannins, which inhibited the fungal growth. Full article

During sulfite delignification of wood, sulfo derivatives of lignin—lignosulfonates (LS)—are formed as a byproduct. Due to their amphiphilic nature, LS are used as plasticizers, dispersants, and stabilizers. The functions and performance characteristics of this surface-active polyelectrolyte are determined by its behavior in aqueous solution, at surfaces and interfaces, which, in turn, is determined by its chemical composition. This study investigated the effect of LS with various molecular weight compositions (M_w 9–50 kDa) on the behavior and aggregation stability of aqueous dispersions of elemental sulfur (S⁰) under conditions simulating hydrothermal leaching of sulfide ores. Using conductometry, potentiometry, tensiometry, and viscometry, a detailed study of the physicochemical properties of aqueous LS solutions (C_LS 0.02–1.28 g/dm³) obtained from a few sources (Krasnokamsk, Solikamsk, and Norwegian Pulp and Paper Mills) was conducted. The composition, molecular weight, and concentration of LS were found to significantly affect their specific electrical conductivity, pH, intrinsic viscosity, and surface activity. LS introduction during the formation of sulfur sols is shown to promote their stabilization through electrostatic and steric mechanisms. Optimum dispersion stability (293 K, pH 4.5–5.5) was observed at moderate LS concentrations (0.02–0.32 g/dm³), when a stable adsorption layer forms on the surface of sulfur particles. High-molecular-weight LS samples provided more effective spatial stabilization of sulfur particles. It has been established that increasing temperature (293–333 K) and changing pH (1–7) significantly affect the aggregative stability of systems; specifically, the sol stability decreases with increasing temperature, and the stabilizing effect of different LS types reverses upon changing pH. The obtained results highlight the potential of using naturally occurring polymeric dispersants to control the aggregation stability of sulfur-containing heterophase systems and can be applied to the design of stable colloidal systems in chemical engineering and hydrometallurgy. Full article

The paper presents select in situ and numerical investigations related to improving the energy efficiency of historic buildings. Using the case study of a historic timber building as an example, the procedure of the in situ investigation of its existing condition is presented. This procedure included measuring the moisture of the timber elements, determining the presence of fungi, mold, and wood-destroying insects, infrared camera inspection, and measuring the microclimate of the rooms. According to the conclusions of the building survey report, conservation guidelines were proposed. On the basis of those proposed guidelines, thermal upgrades were suggested, including insulation on the inside of the envelope components. Detailed numerical calculations were provided for the proposed thermal insulation systems. Those included a hygrothermal performance evaluation in the context of the change in the moisture content of timber elements in the insulated envelope components. The risk of mold development on the surface of selected junctions was also estimated. The key outcome of this study is a proprietary procedure for improving the thermal protection quality of envelope components of historic timber buildings. Full article

The durability of construction and building materials under sulphate environments is an important indicator to evaluate their service life. In this study, the physical and mechanical behaviours of wood-ash-based alkali-activated materials (AAMs) incorporating coal fly ash, metakaolin, natural zeolite, and calcined phosphogypsum were assessed before and after being subjected to sodium sulphate corrosion cycles via the compressive strength, mass, and volume changes. The microstructure, elemental composition, and phase identification were further analysed using X-Ray Diffraction(XRD) and scanning electron microscope(SEM). The results show that the exposure to sulphate solution caused decalcification and dealumination of hydrates, releasing calcium and aluminium to react with sulphate and forming expansive erosion products, ettringite and gypsum. This contributed to the microstructural damage, leading to mass change, volume expansion, and compressive strength loss of 7.33, 1.29, and 60.42%. The introduction of binary aluminosilicate precursors enhanced the sulphate resistance by forming a well-bonded microstructure consisting of calcium (aluminate) silicate hydrate and sodium aluminate silicate hydrate, with the compressive strength loss decreasing up to 18.60%. The co-usage of calcined phosphogypsum deteriorated the mechanical properties of AAMs but significantly improved the sulphate resistance. The sodium sulphate environment facilitated anhydrate hydration, generating more sulphate hydrates and hemigypsums that co-existed with erosion products, forming a compact microstructure and improving the compressive strength by twofold. Full article

While most efforts are aimed at preventing the surface roughening and colour change of wood due to weathering, some customers, mainly for decorative reasons, want wooden objects and elements to give the impression that they have been weathered for a long time. In this study, the simulated weathering of numerous softwoods as well as ring-porous and diffuse-porous woods by sandblasting and greying with iron sulphate was investigated. Calculations of the correlations between wood density, orientation, mass loss and thickness reduction by sandblasting were performed, and the difference between the hardness of late and early wood and the surface profile parameter P_t showed that the surface profiles correlate strongly with mass loss, especially in the tangential orientation. Softwoods appeared to be the most promising for simulated profiling, especially spruce and larch with tangential surfaces. Among the ring-porous woods, oak and sweet chestnut also delivered good results. Full article

Methods for the improvement of regional lignocellulosic resources (wood and agriculture waste) were studied and analyzed using blends with optimized compositions and a selective pretreatment of the blends using microwaves to enhance their thermochemical conversion and energy production efficiency. A batch-size pilot device was used to provide the thermochemical conversion of biomass blends of different compositions, analyzing the synergy of the effects of thermal and chemical interaction between the components on the yield and thermochemical conversion of volatiles, responsible for producing heat energy at various stages of flame formation. To control the thermal decomposition of the biomass, improving the flame characteristics and the produced heat, a selective pretreatment of blends using microwaves (2.45 GHz) was achieved by varying the temperature of microwave pretreatment. Assessing correlations between changes in the main characteristics of pretreated blends (elemental composition and heating value) on the produced heat and composition of products suggests that selective MW pretreatment of biomass blends activates synergistic effects of thermal and chemical interaction, enhancing the yield and combustion of volatiles with a correlating increase in produced heat energy, thus promoting the wider use of renewable biomass resources for sustainable energy production by limiting the use of fossil fuels for heat-energy production and the formation of GHG emissions. Full article

This article presents an algorithm for the assessment of time series data related to the materials used for packaging in the market in Bulgaria for the period 2010–2023. The considered elements include the quantities of the following types of materials: paper/cardboard, plastic, wood, metal, glass, and others. They are extracted from the built relational database and subsequently processed and summarized. In this regard, relevant criteria (rules) are formed and applied and certain variables are calculated. In addition, analysis of variance (Anova) and Tukey’s test are also used for these data. The results show that one of the materials (paper/cardboard) in 2010–2018 has relatively higher quantities compared to the rest materials. A similar situation occurs for the element plastic, in 2019–2023. The calculated relative shares of the respective quantities of packaging materials show that more than half of them in the market are made of paper/cardboard and plastic. Some dynamic changes are observed in the quantities for the materials metal and wood. The indicator values for the other materials are significantly lower than the rest. The developed algorithm can be applied to study other time series data in fields such as ecology, finance, etc. Full article

Bio-polyurethane foam was synthesized in this study using bio-polyol derived from liquefied waste wood as a sustainable alternative to petroleum-based polyols. It has been widely reported that polyurethane foams incorporating liquefied wood exhibit biodegradability when buried in soil, with assessments typically relying on CO₂ emission measurements in a close system. However, this method cannot obtain any chemical bonding breakage information of the bio-polyurethane foam. On the other hand, our study investigated the biodegradation process by employing an elemental composition analysis using a CHN coder and functional group analysis through Fourier transform infrared (FT-IR) spectroscopy to capture chemical structure changing. The results demonstrated that biodegradation occurs in three different stages over time, even in the absence of significant early-stage weight loss. The gradual breakdown of urethane bonds was confirmed through changes in the elemental composition and functional group ratios, providing a more detailed understanding of the degradation mechanism. These findings suggest highlighting the importance of complementary chemical analytical techniques for a more accurate evaluation. On the other hand, TG data showed that bio-polyurethane foams remained thermally stable even after biodegradation occurred. Full article

Forest wood biomass is a key renewable resource for advancing energy transition and mitigating climate change. This review analyzes the physicochemical properties of forest biomass from major European tree species to assess their suitability for bioenergy applications. This study encompasses key parameters, such as moisture content, ash content, volatile matter, fixed carbon, elemental composition, bulk density, and energy content (HHV and LHV). This review analyzed data from 43 publications and extracted 140 records concerning the physicochemical properties of the most common European forest species used for bioenergy. The most commonly represented species were Quercus robur, Eucalyptus spp., and Fagus sylvatica. Moisture content, referring to fresh matter, ranged from 5% to 65%; ash content, referring to a dry basis, ranged from 0.2% to 3.5%; and higher heating value (HHV), referring to dry matter, ranged from 17 to 21 MJ kg⁻¹. This study highlights variability among species and underscores the importance of standardizing biomass characterization methods and the scarcity of data on bulk density and other key logistical parameters. These findings emphasize the need for consistent methodologies and species-specific selection strategies to optimize sustainability and efficiency in forest biomass utilization for bioenergy. Full article

As part of the transition to low-carbon energy and for the sustainable utilisation of resources, it is necessary to seek a replacement for solid fossil fuels, but unfortunately, it is impossible to completely abandon them for various reasons at the moment, so only partial replacement with new, high-calorific, biomass-based fuels is possible. The purpose of this work is to determine the typical parameters of the co-combustion of carbonisate, coal and their mixtures, taking into account the synergetic effects influencing the combustion intensity of the mixture. Carbonisate was obtained in the process of the gasification of pinewood through the counter-blowing method at a temperature of 800–900 °C, while air was used as an oxidant. Basically, this method of gasification is used for coal in order to obtain high-calorific coke for the metallurgical industry. Also, in this study, for the first time, carbonisate was obtained from 50% pinewood and 50% lignite. The O/C and H/C ratios were determined for carbonisate. A technical and elemental analysis of the investigated fuels was carried out. A thermal analysis in oxidising medium was applied to determining the typical combustion parameters in the process of slow heating of the fuels under study. According to the results of this thermal analysis, typical heating parameters such as the ignition temperature, burnout temperature, maximum mass loss rate, combustion index, etc., were determined. It was noted that the calorific value of carbonised wood is two times higher than that of coal. The combustion index of carbonisates is 2.5–36% lower compared to that of coal. According to the results of the analysis of the interaction of the components among themselves (in the process of their joint combustion), the presence of synergetic interactions between the components was determined, which affected the change in the combustion intensity and heat release intensity. The results of this study may be useful for retrofitting coal-fired boilers to run on a mixture containing carbonisate and lignite. If carbonisate is produced from biomass, the resulting gas could be used as an energy fuel by burning it in a coal-fired boiler. Full article

Resonance boards of Chinese traditional instruments such as the Guzheng and Guqin typically are arched, with the arch height influencing their resonance characteristics. This study focuses on Paulownia wood utilized for resonance boards. The bottom surfaces were thinned in 1 mm increments, with vibration signatures acquired at each reduction stage using a multi-channel FFT analyzer. Subsequently, time-domain characteristic parameters of the signals were extracted through MATLAB-based signal processing. Modal and harmonic response simulations of the structure were conducted using finite element software. The results indicated that variations in arch height affected the frequency spectrum response of the vibrations of Paulownia wood, altering the structural energy radiation levels. Lower arch heights (0–2 mm) had a greater impact on the fundamental frequency. The arch height was 1 mm and 2 mm, with R1,1 and R1,2 being −5.31% and −8.62%, respectively. Skewness and kurtosis were negatively correlated with arch height. When ΔH was 3.06, the radiation effect was optimal. The changes in arch height influenced the vibrational modes and energy distribution of Paulownia. Higher arch heights (3–6 mm) have less effect on the fundamental frequency and impose some constraints on the mode vibration pattern. Furthermore, the results of the frequency-domain and time-domain analyses were found to be largely consistent with the finite element simulation results. The results provide guidance for changing the arch height to modulate the acoustic vibration response of the resonance board, which is of significance for the personalized design of future musical instruments. Full article

This work aimed to analyze the PAH content in products smoked in traditional smokehouses with direct and indirect heat sources and in an industrial way as an element of PAH content monitoring in Polish market products. This research material comprised 12 smoked meats (W) and 38 sausages (K), medium or coarsely minced. The content of benzo(a)pyrene and the total content of four marker PAHs was determined by GC-MS. The analysis showed a significantly higher level of PAH contamination in products smoked using traditional methods. The results also indicate that the natural casing is not a barrier against PAH contamination during traditional smoking, and a higher degree of meat fragmentation, together with a small cross-section, increases the PAH content in this technological group. Concentrations of benzo(a)pyrene exceeding the permissible levels were found in the sausages smoked for more than 60 min. As part of the strategies for reducing the PAH content, among others, changing the furnace to an indirect one, shortening the time, lowering the smoking temperature, using artificial casings or removing casings before consumption, drying the product surface before the smoking process, using seasoned and bark-free wood, as well as additional smokehouse equipment, are recommended. Full article

In view of the application status and technical challenges of steel–wood composite joints in architecture, this paper proposes an innovative connection technology to solve issues such as susceptibility to pry-out at beam–column joints and low load-bearing capacity and to provide various reinforcement methods in order to meet the different structural requirements and economic benefits. By designing and manufacturing four groups of beam–column joint specimens with different reinforcement methods, including no reinforcement, structural adhesive and angle steel reinforcement, 4 mm thick steel sleeve reinforcement, and 6 mm thick steel sleeve reinforcement, monotonic loading tests and finite element simulations were carried out, respectively. This research found that unreinforced specimens and structural adhesive angle steel-reinforced joints exhibited obvious mortise and tenon compression deformation and, moreover, tenon pulling phenomena at load values of approximately 2 kN and 2.6 kN, respectively. However, the joint reinforced by a steel sleeve showed a significant improvement in the tenon pulling phenomenon and demonstrated excellent initial stiffness characteristics. The failure mode of the steel sleeve-reinforced joints is primarily characterized by the propagation of cracks at the edges of the steel plate and the tearing of the wood, but the overall structure remains intact. The initial rotational stiffness of the joints reinforced with angle steel and self-tapping screws, the joints reinforced with 4 mm thick steel sleeves, and the joints reinforced with 6 mm thick steel sleeves are 3.96, 6.99, and 13.62 times that of the pure wooden joints, while the ultimate bending moments are 1.97, 7.11, and 7.39 times, respectively. Using finite element software to simulate four groups of joints to observe their stress changes, the areas with high stress in the joints without sleeve reinforcement are mainly located at the upper and lower ends of the tenon, where the compressive stress at the upper edge of the tenon and the tensile stress at the lower flange are both distributed along the grain direction of the beam. The stress on the column sleeve of the joints reinforced with steel sleeves and bolts is relatively low, while the areas with high strain in the beam sleeve are mainly concentrated on the side with the welded stiffeners and its surroundings; the strain around the bolt holes is also quite noticeable. Full article

Wood modification with graphene oxide can give it unique features characteristic of other materials. However, the durability of the newly acquired features is of great importance. To better understand them, it is worth conducting an in-depth analysis of the structural changes that occur in wood under the influence of modification with graphene oxide. As part of the research, wood was impregnated with aqueous graphene oxide dispersion. Wood was impregnated using two methods: single vacuum and pressureless with ultrasound. Laser-assisted ionization spectroscopy (LIBS) was used to determine elements, mainly carbon, and to characterize differences in the elemental composition between the surface layers of wood impregnated with graphene oxide and native wood. Changes in the structure of polymers building wood tissue were analyzed using LIBS and FTIR spectrometry. The wood surface was also imaged using three microscopic techniques (stereomicroscope, confocal laser scanning microscope, and scanning electron microscopy). LIBS showed that graphene oxide was deposited on the surface of impregnated wood, and the intensity of carbon signals in wood impregnated with graphene oxide using vacuum and ultrasound differed. The content of carbon, magnesium, and oxygen elements in the surface layers of wood impregnated with graphene oxide using ultrasound was lower than in vacuum-impregnated wood. Analysis of FTIR spectra showed effective incorporation of graphene oxide into the surface layer of wood. Full article

Algae communities as primary producers are essential elements of aquatic ecosystems and contribute significantly to oxygen production, carbon dioxide fixation, and nutrient transport processes in water bodies. The use of algae-based carbon capture and storage technologies does not produce harmful by-products that require disposal, and the resulting algal biomass can be valuable across various industrial sectors. In this study, model experiments were conducted to develop sequential absorption–microalgae hybrid CO₂-capture methods. To facilitate CO₂ capture from flue gases, wood biomass ash (WBA), an agricultural by-product, was utilized for its alkaline properties, while the flue gas scrubbing medium was regenerated by algae that restored alkalinity during their growth. In our experiments, one of our goals was to determine the optimal conditions for achieving maximum algal biomass growth in the shortest possible time. The suitability of WBA for flue gas cleaning was tested via simulation of CO₂ introduction. Moreover, a method was developed to determine the dissolved inorganic carbon content with the use of an OxiTop device monitoring the changes in pressure. The applied device was a closed, static, and pressure-based respirometer originally designed to determine the biological activity of microorganisms in both solid and liquid samples. In addition, the effects of CO₂-enriched WBA extract on algae cultivation were also analyzed, confirming that it imposed no growth inhibition and identifying the concentration (10% WBA) that optimally promoted algal growth. The optimal initial algal concentration and nutrient conditions for maximum growth were also determined. Full article