Search Results (801)

There has been growing interest in constructing mid- and high-rise wooden buildings in recent years. To ensure the feasibility of these structures, it is necessary to provide evidence that their long-term reliability can be guaranteed. While long-term testing is typically necessary, a continuous monitoring system for the moisture content of wood materials used in buildings has been proposed as an alternative. The proposed method measures the change in the local moisture content using the equilibrium moisture content calculated from the temperature and humidity measured using temperature and humidity sensors. The study used Japanese cypress specimens with dimensions of 50 mm, 75 mm, and 100 mm cubes and Douglas fir specimens of 50 mm cubes. The moisture content was measured under various external environments. Results showed that this system effectively captured changes in local moisture content, reflecting fluctuations in temperature and humidity in a controlled thermo-hygrostat over a three-day moisture absorption environment (20 °C, 95% humidity). Additionally, it was observed that higher moisture content levels yielded correspondingly higher local moisture content measurements compared to those obtained using the oven-drying method. Full article

The transition to sustainable energy sources has intensified interest in lignocellulosic biomass (LCB) as a feedstock for second-generation biofuels. However, the inherent structural recalcitrance of LCB requires the utilization of an effective pretreatment to enhance enzymatic hydrolysis and subsequent fermentation yields. This manuscript presents a novel, single-step, and optimized nitrogen explosive decompression system (NED 3.0) designed to address the critical limitations of earlier NED versions by enabling the in situ removal of inhibitory compounds from biomass slurry and fermentation inefficiency at elevated temperatures, thereby reducing or eliminating the need for post-treatment detoxification. Aspen wood (Populus tremula) was pretreated by NED 3.0 at 200 °C, followed by enzymatic hydrolysis and fermentation. The analytical results confirmed substantial reductions in common fermentation inhibitors, such as acetic acid (up to 2.18 g/100 g dry biomass) and furfural (0.18 g/100 g dry biomass), during early filtrate recovery. Hydrolysate analysis revealed a glucose yield of 26.41 g/100 g dry biomass, corresponding to a hydrolysis efficiency of 41.3%. Fermentation yielded up to 8.05 g ethanol/100 g dry biomass and achieved a fermentation efficiency of 59.8%. Inhibitor concentrations in both hydrolysate and fermentation broth remained within tolerable limits, allowing for effective glucose release and sustained fermentation performance. Compared with earlier NED configurations, the optimized system improved sugar recovery and ethanol production. These findings confirm the operational advantages of NED 3.0, including reduced inhibitory stress, simplified process integration, and chemical-free operation, underscoring its potential for scalability in line with the EU Green Deal for bioethanol production from woody biomass. Full article

Solid fuels are still widely used in household heating in Europe and North America. Emissions from boilers are released in proximity to people. Therefore, there is a need to minimise the toxicity of emissions affecting human health to the greatest extent possible. This study compares the genotoxic potential of the emissions of four boilers of modern and old design (automatic, gasification, down-draft, over-fire) operating at reduced output to simulate the real-life combustion fed by various fossil and renewable solid fuels (hard coal, brown coal, brown coal briquettes, wood pellets, wet and dry spruce). Organic emissions were tested for genotoxic potential by analysing bulky DNA adducts and 8-oxo-dG adduct induction. There was no consistent genotoxic pattern among the fuels used within the boilers. Genotoxicity was strongly correlated with polycyclic aromatic hydrocarbon (PAH) content, and even stronger correlation was observed with particulate matter (PM). In all measured variables (PM, PAHs, genotoxicity), the technology of the boilers was a more important factor in determining the genotoxic potential than the fuels burned. The highest levels of both bulky and 8-oxo-dG DNA adducts were induced by organics originating from the over-fire boiler, while the automatic boiler exhibited genotoxic potential that was ~1000- and 100-fold lower, respectively. Full article

Residential and agricultural buildings must prioritize environmental sustainability, employing locally sourced, bio/geologically sustainable materials, and reversible construction methods. Hence, adobe construction and earth-based building methods are experiencing a comeback. This article describes the hygrothermal performances of a real scale agricultural building prototype, in real field conditions, built and designed to be energy-efficient, environmentally friendly, and well-suited for the hot, dry climates typical of the Mediterranean region during summer. The building prototype is a small modular two room construction, one room based on wood (for control purpose) and the other one on raw earth. The experimental set up highlights the passive cooling and humidity regulation potential provided by raw earth and adobe brick technology in agricultural buildings used for fruit and vegetable storage. Such passive cooling alternatives in the Mediterranean climate could reduce the need for energy-intensive and environmentally impactful cold storage rooms. Full article

Societies are aiming to have a higher ecological consciousness in wastewater treatment operations and achieve a more sustainable future. With this said, global demands for larger quantities of resources and the consequent waste generated will inevitably lead to the exhaustion of current municipal wastewater treatment works. The utilization of biosolids (particularly microbial proteins) from wastewater treatment operations could generate a sustainable bio-adhesive for the wood industry, reduce carbon footprint, mitigate health concerns related to the use of carcinogenic components, and support a more circular economic option for wastewater treatment. A techno-economic analysis for three 10 MGD wastewater treatment operations producing roughly 11,300 dry pounds of biosolids per day, in conjunction with co-feedstock defatted soy flour protein at varying ratios (i.e., 0%, 15%, and 50% wet weight), was conducted. Aspen Capital Cost Estimator V12 was used to design and estimate installed equipment additions for wastewater treatment plant integration into an urban biorefinery process. Due to the mechanical attributes and market competition, the chosen selling prices of each adhesive per pound were set for analysis as USD 0.75 for Plant Option P1, USD 0.85 for Plant Option P2, and USD 1.00 for Plant Option P3. Over a 20-year life, each plant option demonstrated economic viability with high NPVs of USD 107.9M, USD 178.7M, and USD 502.2M and internal rates of return (IRRs) of 24.0%, 29.0%, and 44.2% respectively. The options examined have low production costs of USD 0.14 and USD 0.19 per pound, minimum selling prices of USD 0.42–USD 0.51 per pound, resulting in between 2- and 4-year payback periods. Sensitivity analysis shows the effects biosolid production fluctuations, raw material market price, and adhesive selling price have on economics. The results proved profitable even with large variations in the feedstock and raw material prices, requiring low market selling prices to reach the hurdle rate of examination. This technology is economically enticing, and the positive environmental impact of waste utilization encourages further development and analysis of the bio-adhesive process. Full article

This paper describes the process of drying sewage sludge mixtures with the addition of various components: straw chaff, wood sawdust, ash, bark, wood chips, and walnut shells. The tests were conducted in two series: summer and autumn (with maximum insolation of 24.1 and 29.8 MJ∙m⁻², respectively). Using a set of sensors with which the experimental station was equipped, the parameters of the environment (temperature, humidity, and insolation) and the parameters of the dried mixtures (temperature and humidity) were measured. Based on the results obtained, the influence of external factors on the parameters, time, and drying effect of the respective mixtures was analyzed. With the initial moisture content of the mixtures ranging from 41 to 79%, a final moisture content of 6 to 49% was obtained, depending on the components and drying conditions. It was found that the drying rate was most influenced by the amount of solar energy and the associated outdoor (maximum 29 °C and 19 °C) and indoor (maximum 33 °C and 24 °C) air temperatures, and in the second series, there was an additional effect of the temperature of the mixtures (maximum 30 °C), upon which the intensity of water evaporation depended. Straw chaff and walnut shells proved to be the best additives, for which the highest drying rates were obtained (max. 50 to 60% humidity drop). The possibility of using dried materials for agricultural and energy purposes was indicated. This approach is in line with the principles of sustainable development. Full article

Climate models forecast warmer winter conditions, which could lead to an earlier spring xylem phenology in trees. Localized stem heat experiments mimic this situation and have shown that stem warming leads to an earlier cambial resumption in evergreen conifers. However, there are still few comprehensive studies comparing the responses to stem heating in coexisting conifers and hardwoods, particularly in drought-prone regions where temperatures are rising. We addressed this issue by comparing the responses (xylem phenology, wood anatomy, growth, and sapwood concentrations of non-structural carbohydrates—NSCs) of two pines (the Eurosiberian Pinus sylvestris L., and the Mediterranean Pinus pinaster Ait.) and a ring-porous oak (Quercus pyrenaica Willd.) to stem heating. We used the Vaganov-Shashkin growth model (VS model) to simulate growth phenology considering several emission scenarios and warming rates. Stem heating in winter advanced cambial phenology in P. pinaster and Q. pyrenaica and enhanced radial growth of the three species 1–2 years after the treatment, but reduced the transversal lumen area of earlywood conduits. P. sylvestris showed a rapid and high growth enhancement, whereas the oak responded with a 1-year delay. Heated P. pinaster and Q. pyrenaica trees showed lower sapwood starch concentrations than non-heated trees. These results partially agree with projections of the VS model, which forecasts earlier growth onset, particularly in P. pinaster, as climate warms. Climate-growth correlations show that growth may be enhanced by warm conditions in late winter but also reduced if this is followed by dry-warm growing seasons. Therefore, forecasted advancements of xylem onset in spring in response to warmer winters may not necessarily translate into enhanced growth if warming reduces the hydraulic conductivity and growing seasons become drier. Full article

Selecting the most suitable machines to use for wood recovery is essential for computing the operating costs of the whole forestry machinery chain (FMC). Nevertheless, a generalized approach for selecting the most suitable FMC and quantifying the corresponding economic performances for wood recovery (i.e., harvesting and long-distance transport) is still missing. The primary aim of this study is to describe a decision support model, called FOREstry MAchinery chain selection (“FOREMA v1”), which is able to (i) select the most feasible FMC and (ii) calculate the costs (such as EUR∙h⁻¹; EUR∙t⁻¹ of dry matter, DM) of each operation (OP) comprising the FMC. The model is made up of three different modules (Ms): machinery chain selection (M1), machinery chain organization (M2), and cost calculation (M3). In M1, feasible FMCs are defined according to seven technical parameters that characterize the forest area. For each FMC, FOREMA v1 defines the sequence of OPs and the types of machines that can potentially be used. Once the characteristics of the area in which wood recovery occurs are processed, the user selects the types of machines to use according to the model’s suggestions. In M2 and M3, the user is supported in organizing the FMC (e.g., calculation of the required time, working productivity, and so on) and computing the operating costs. The secondary aim of this study is to discuss a case study focused on chips production for energy generation, providing empirical evidence on how FOREMA v1 works. The proposed model provides a systematic approach for the selection and optimization of the most suitable FMC to adopt for biomass recovery, thus supporting decision-making processes. The results showed that felling had the lowest cost per unit of time (63.7 EUR·h⁻¹) but the highest cost per unit of mass (35.4 EUR·t DM⁻¹) due to its longer working time and lower productivity. Loading and long-distance transport incurred the highest costs both per unit of time (223.5 EUR·h⁻¹) and per unit of mass (29.4 EUR·t DM⁻¹), attributed to the use of medium–small-sized trailers coupled with tractors operating at low speeds, leading to a high number of cycles. For the entire FMC the costs were equal to 147.3 EUR·h⁻¹ and 101.1 EUR·t DM⁻¹. Full article

Oak wood color plays a critical role in veneer production, where visual consistency directly affects material value. However, production choices are still often based on experience rather than systematic scientific data. Although many studies have examined individual factors affecting wood color, such as species or drying conditions, few have brought together ecological and industrial perspectives. This review addresses that gap by examining how habitat, species characteristics, and processing parameters influence color variation in Quercus robur and Quercus petraea. A structured literature review was conducted using Web of Science, Scopus, and Google Scholar, complemented by industry observations. The results show that site-specific factors—such as soil type, forest type, and regional climate—can significantly affect oak wood color, in some cases more than genetic differences. Drying methods, wood age, and log storage also contribute to variations in color and homogeneity. These findings highlight the potential for better raw material selection and processing strategies, leading to improved quality, sustainability, and economic efficiency in veneer production. Remaining knowledge gaps—particularly in predictive modeling and veneer-specific studies—point to important areas for future research. Full article

Recycled wood fiber (RWF) obtained through the multi-stage processing of waste wood serves as an eco-friendly green construction material, exhibiting lightweight, porous, and high toughness characteristics that demonstrate significant potential as a cementitious reinforcement, offering strategic advantages for environmental protection and resource recycling. In this study, high-performance sulfoaluminate cement (SAC)-RWF composites prepared by modifying RWFs with nano-silica (NS) and a silane coupling agent (KH560) were developed and their effects on mechanical properties, shrinkage behavior, hydration characteristics, and microstructure of SAC-RWF composites were systematically investigated. Optimal performance was achieved at water–cement ratio of 0.5 with 20% RWF content, where the KH560-modified samples showed superior improvement, with 8.5% and 14.3% increases in 28 d flexural and compressive strength, respectively, compared to the control groups, outperforming the NS-modified samples (3.6% and 8.6% enhancements). Both modifiers improved durability, reducing water absorption by 6.72% (NS) and 7.1% (KH560) while decreasing drying shrinkage by 4.3% and 27.2%, respectively. The modified SAC composites maintained favorable thermal properties, with NS reducing thermal conductivity by 6.8% through density optimization, whereas the KH560-treated specimens retained low conductivity despite slight density increases. Micro-structural tests revealed accelerated hydration without new hydration product formation, with both modifiers enhancing cementitious matrix hydration product generation by distinct mechanisms—with NS acting through physical pore-filling, while KH560 established Si-O-C chemical bonds at paste interfaces. Although both modifications improved mechanical properties and durability, the KH560-modified SAC composite group demonstrated superior overall performance than the NS-modified group, providing a technical pathway for developing sustainable, high-performance recycled wood fiber cement-based materials with balanced functional properties for low-carbon construction applications. Full article

Occupational exposure to commercial formic and acetic acids through dermal contact and inhalation during rubber sheet processing poses significant health risks to workers. Additionally, the use of these acids contributes to environmental pollution by contaminating water sources and soil. This study investigates the potential of three types of wood vinegar—derived from para-rubber wood, bamboo, and eucalyptus—obtained through biomass pyrolysis under anaerobic conditions, as sustainable alternatives to formic and acetic acids in the production of ribbed smoked sheets (RSSs). The organic constituents of each wood vinegar were characterized using gas chromatography and subsequently mixed with fresh natural latex to produce coagulated rubber sheets. The physical and chemical properties, equilibrium moisture content, and drying kinetics of the resulting sheets were then evaluated. The results indicated that wood vinegar derived from para-rubber wood contained a higher concentration of acetic acid compared to that obtained from bamboo and eucalyptus. As a result, rubber sheets coagulated with para-rubber wood and bamboo vinegars exhibited moisture sorption isotherms comparable to those of sheets coagulated with acetic acid, best described by the modified Henderson model. In contrast, sheets coagulated with eucalyptus-derived vinegar and formic acid followed the Oswin model. In terms of physical and chemical properties, extended drying times led to improved tensile strength in all samples. No statistically significant differences in tensile strength were observed between the experimental and reference samples. The concentration of acid was found to influence Mooney viscosity, the plasticity retention index (PRI), the thermogravimetric curve, and the overall coagulation process more significantly than the acid type. The drying kinetics of all five rubber sheet samples displayed similar trends, with the drying time decreasing in response to increases in drying temperature and airflow velocity. Full article

Drying constitutes an essential step in aerogel fabrication, where the drying method directly determines the pore structure and consequently influences the material’s functionality. This study employed various drying techniques to prepare balsa-wood-derived aerogels, systematically investigating their effects on microstructure, density, and performance characteristics. The results demonstrate that different drying methods regulate aerogels through distinct pore structure modifications. Supercritical CO₂ drying optimally preserves the native wood microstructure, yielding aerogels with superior thermal insulation performance. Freeze-drying induces the formation of ice crystals, which reconstructs the microstructure, resulting in aerogels with minimal density, significantly enhanced permeability, and exceptional cyclic water absorption capacity. Vacuum drying, oven drying, and natural drying all lead to significant deformation of the aerogel pore structure. Among them, oven drying increases the pore quantity of aerogels through volumetric contraction, thereby achieving the highest specific surface area. However, aerogels prepared by air drying have the highest density and the poorest thermal insulation performance. This study demonstrates that precise control of liquid surface tension during drying can effectively regulate both the pore architecture and functional performance of wood-derived aerogels. The findings offer fundamental insights into tailoring aerogel properties through optimized drying processes, providing valuable guidance for material design and application development. Full article

Fungi are a diverse and essential group that play crucial ecological roles. However, they remain understudied in tropical countries like Ecuador in terms of their forest or protected areas, particularly across diverse ecosystem zones such as seasonal forests and salt flats. This study aimed to inventory fungal diversity in two specific zones: the dry forest (DF) and the salt flat (SF) within the Reserva Ecologica Arenillas (REAR), located in El Oro, Ecuador. The results recorded 162 specimens representing 47 species belonging to 34 genera, identified morphologically. Although statistically significant, the difference in species richness and abundance between the dry forest and the salt flat was minimal, with the dry forest showing slightly higher values. Nonetheless, certain species were prevalent in both ecosystems, such as Cerrena hydnoides, Pycnoporus sanguineus, Hexagonia tenuis, and Chondrostereum sp., alongside four species with resupinate habit, all of them growing on decayed wood. The Shannon and Simpson indices were calculated to assess alpha diversity, revealing higher diversity in the DF. To evaluate differences in community composition between habitats, non-metric multidimensional scaling (NMDS) and permutational analysis of variance (PERMANOVA) were applied, indicating greater species turnover and dominance of specific taxa in the DF compared to the SF. These findings highlight the importance of the fungal diversity found in the REAR while also pointing to the need for more exhaustive monitoring and comparative studies with other wild or protected areas to fully understand and conserve this biodiversity. Full article

Wood–textile composites (WTCs), consisting of polypropylene and woven willow wood, have potential for both interior and exterior applications. However, their basic materials are not inherently resistant to outdoor weathering. This study examines the impact of various climatic conditions on the material behavior of WTCs. The composite and its components were aged under different scenarios, including kiln-drying, frost, standard and tropical climate, and artificial weathering and water storage, and analyzed for dimensional stability, chemical changes (FTIR), mechanical damage (µ-CT), and mechanical performance. While kiln-drying, frost, and tropical climates had only minor effects, water storage caused swelling-related damage, resulting in a 45% decrease in Young’s modulus but increased elongation at break (+88%) and impact strength (+75%). Artificial weathering led to significant degradation: tensile strength declined by 28%, Young’s modulus by 49%, and impact strength by 26%. In the medium term, this degradation compromises the integrity of the composite. The results highlight the need for effective stabilization measures—such as polymer modification or structural protection—to ensure the long-term durability of WTCs in outdoor use. Full article

Wood, as a natural and renewable resource, plays a crucial role in industrial production and daily life. Lignin, as one of the three major components of the plant cell secondary wall, plays a key role in conferring mechanical strength and enhancing stress resistance. The caffeic acid-O-methyltransferase (COMT) family of oxygen-methyltransferases is a core regulatory node in the downstream pathway of lignin biosynthesis. Here, our report shows that caffeic acid-O-methyltransferase 2 (COMT2) exhibits high conservation across several species. Tissue expression analysis reveals that COMT2 is specifically highly expressed in the secondary xylem of Populus tomentosa stems. We demonstrated that the specific overexpression of COMT2 in fiber cells of Populus tomentosa led to a significant increase in plant height, stem diameter, internode number, and stem dry weight. Furthermore, we found that the specific overexpression of COMT2 in fiber cells promotes xylem differentiation, lignin accumulation, and the thickening of the secondary cell wall (SCW) in fiber cells. Our results indicate that key downstream lignin biosynthesis enzyme genes are upregulated in transgenic plants. Additionally, mechanical properties of stem bending resistance, puncture resistance, and compressive strength in the transgenic lines are significantly improved. Moreover, we further created the DUFpro:COMT2 transgenic lines of Populus deltoides × Populus. euramericana cv ‘Nanlin895’ to verify the functional conservation of COMT2 in closely related poplar species. The DUFpro:COMT2 Populus deltoides × Populus. euramericana cv ‘Nanlin895’ transgenic lines exhibited phenotypes similar to those observed in the P. tomentosa transgenic plants, which showed enhanced growth, increased lignin accumulation, and greater wood strength. Overall, the specific overexpression of the caffeic acid O-methyltransferase gene COMT2 in poplar stem fiber cells has enhanced the wood biomass, wood properties, and mechanical strength of poplar stems. Full article