Search Results (59)

To address the issues of poor thermal performance and high energy consumption in rural dwellings in cold regions of China, this study investigates multi-type energy-efficient retrofitting strategies for rural houses in the Hebei–Tianjin region. By utilizing a two-step cluster analysis method, 458 rural dwellings from 32 villages were classified based on household demographics, architectural features, and energy consumption patterns, identifying three typical categories: pre-1980s adobe dwellings, 1980s–1990s brick–wood structures, and post-1990s brick–concrete houses. Tailored sunspace design strategies were proposed through simulation: low-cost plastic film sunspaces for adobe dwellings (dynamic payback period: 2.8 years; net present value: CNY 2343), 10 mm hollow polycarbonate (PC) panels for brick–wood structures (cost–benefit ratio: 1.72), and high-efficiency broken bridge aluminum Low-e sunspaces for brick–concrete houses (annual natural gas savings: 345.24 m³). Economic analysis confirmed the feasibility of the selected strategies, with positive net present values and cost–benefit ratios exceeding 1. The findings demonstrate that classification-based retrofitting strategies effectively balance energy-saving benefits with economic costs, providing a scientific hierarchical implementation framework for rural residential energy efficiency improvements in cold regions. Full article

To bridge the mechanical performance gap between polyethylene terephthalate (PET) foam cores and balsa wood in wind turbine blades, this study proposes a hierarchical groove-perforation design for structural optimization. A finite element model integrating PET foam and epoxy resin was developed and validated against experimental shear modulus data (α < 0.5%). Machine learning combined with a multi-island genetic algorithm (MIGA) optimized groove parameters (spacing: 7.5–30 mm, width: 0.9–2 mm, depth: 0–23.5 mm, perforation angle: 45–90°) under constant resin infusion. The optimal configuration (width: 1 mm, spacing: 15 mm, angle: 65°) increased the shear modulus by 9.2% (from 125 MPa to 137.1 MPa) and enhanced compressive/tensile modulus by 10.7% compared to conventional designs, without increasing core mass. Stress distribution analysis demonstrated that secondary grooves improved resin infiltration uniformity and interfacial stress transfer, reducing localized strain concentration. Further integration of machine learning with MIGA for parameter optimization enabled the shear modulus to reach 150 MPa while minimizing weight gain, achieving a balance between structural performance and material efficiency. This hierarchical optimization strategy offers a cost-effective and lightweight alternative to balsa, promoting broader application of PET foam cores in wind energy and other high-performance composite structures. Full article

The main objective of energy balance analysis is to guide farmers in making informed decisions that promote the efficient management of natural resources, optimise the use of agricultural inputs, and improve the overall economic performance of their farms. In addition, it supports the adoption of sustainable agricultural practices, such as crop diversification, the use of renewable energy sources, and the recycling of agricultural by-products and residues into natural energy sources or fertilisers. This paper analyses the variation in energy efficiency between 2019 and 2022 of the main crops in Angola: maize, soybean, and rice, and the forest production of eucalyptus biomass in agroforestry farms. The research was based on the responses to interviews conducted with the managers of the farms regarding the machinery used, fuels and lubricants, labour, seeds, phytopharmaceuticals, and fertilisers. The quantities are gathered by converting data into Megajoules (MJ). The results show variations in efficiency and energy balance. In corn, efficiency fluctuated between 1.32 MJ in 2019 and 1.41 MJ in 2020, falling to 0.94 MJ in 2021 due to the COVID-19 pandemic before rising to 1.31 MJ in 2022. For soybeans, the energy balance went from a deficit of −8223.48 MJ in 2019 to a positive 11,974.62 MJ in 2022, indicating better use of resources. Rice stood out for its high efficiency, reaching 81,541.33 MJ in 2021, while wood production showed negative balances, evidencing the need for more effective strategies. This research concludes that understanding the energy balance of agricultural operations in Angola is essential not only to achieve greater sustainability and profitability but also to strengthen the resilience of agricultural systems against external factors such as climate change, fluctuations in input prices, and economic crises. A comprehensive understanding of the energy balance allows farmers to assess the true cost-effectiveness of their operations, identify energy inefficiencies, and implement more effective strategies to maximise productivity while minimising environmental impacts. Full article

Pruning wood mass is crucial for grapevine management, as it reflects the vine’s vigor and balance. However, traditional manual measurement methods are time-consuming and labor-intensive. Recent advances in digital imaging offer non-invasive techniques, but limited research has explored pruning wood weight estimation, especially regarding the use of artificial backgrounds and lighting. This study assesses the use of image analysis for estimating wood weight, focusing on image acquisition conditions. This research aimed to (i) evaluate the necessity of artificial backgrounds and (ii) identify optimal daylight conditions for accurate image capture. Results demonstrated that estimation accuracy strongly depends on the sun’s position relative to the camera. The highest accuracy was achieved when the camera faced direct sunlight (morning on the northwest canopy side and afternoon on the southeast side), with R² values reaching 0.90 and 0.93, and RMSE as low as 44.24 g. Artificial backgrounds did not significantly enhance performance, suggesting that the method is applicable under field conditions. Leave-One-Group-Out Cross-Validation (LOGOCV) confirmed the model’s robustness when applied to Catarratto cv. (LOGOCV R² = 0.86 in NB and 0.84 in WB), though performance varied across other cultivars. These findings highlight the potential of automated image-based assessment for efficient vineyard management, using minimal effort adjustments to image collection that can be incorporated into low-cost setups for pruning wood weight estimation. Full article

A simple procedure is proposed for the sustainable selection of materials for interior design. The procedure is based on structural, environmental, and material cost analysis. For structural analysis, finite element models are used to analyze the behavior in terms of stress and strains and to optimize the product size. For environmental analysis, the assessment focuses on the carbon footprint of each material, considering CO₂ emissions throughout its lifecycle. To show the potentialities of the proposed procedure, the Iso-Lounge chair by Jasper Morrison was selected as a case study. The research evaluates three materials (plywood, polypropylene, and polycarbonate), assessing their mechanical properties, cost implications, and CO₂ emissions. Results indicate that plywood, with a reduced thickness in the redesigned model, maintains structural integrity while significantly lowering the amount of material used. Compared to polypropylene and polycarbonate, which required greater thickness, plywood demonstrated superior mechanical efficiency and cost-effectiveness. Additionally, CO₂ emissions analysis revealed that plywood had a lower footprint than polycarbonate and was comparable to polypropylene. These findings highlight the advantages of engineered wood in sustainable furniture design, offering a balance between performance, affordability, and environmental responsibility. The redesign approach optimizes material use, demonstrating the potential for reducing waste and enhancing sustainability in structural applications. Full article

This paper presents an experimental and numerical investigation of a 254 mm resin-printed propeller operating at rotational speeds between 3000 and 9000 RPM. Propeller thrust and torque were measured using a six-degree-of-freedom load cell, while acoustic data were captured with a microphone positioned three times the propeller diameter from the center. To complement the experimental analysis, computational simulations were conducted using ANSYS Fluent with the detached eddy simulation (DES) model, the Ffowcs-Williams and Hawkings (FW-H) model, and a transient flow solver. The figure of merit (FM) results show that the resin propeller slightly outperforms two commercial counterparts with a marginal difference between the wood and resin propellers. Additionally, the resin propeller demonstrates better noise performance, exhibiting the lowest primary tonal noise, broadband noise, and overall sound pressure level (OASPL), with minimal differences between the two commercial counterparts. ANSYS Fluent simulations predict thrust and torque within a 10% error margin, showing particularly accurate results for primary tonal noise. A new trade-off index is proposed to assess the balance between propeller performance and aeroacoustics, revealing distinct trends compared to traditional metrics. Furthermore, aerodynamic phenomena such as flow separation on the leading edge near the tip, flow separation behind the middle trailing edge, and vortex interactions at the root are identified as key contributors to tonal and broadband noise. These findings provide valuable insights into propeller design and aeroacoustic optimization. Full article

This study aims to evaluate the growth characteristics of six Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) provenances (S1–S6) from different climatic regions in subtropical China in order to select superior provenances with strong adaptability, fast growth, and reasonable biomass allocation. These results will provide references for genetic improvement and resource utilization of Chinese fir plantations. A total of 385 trees, aged 26 to 48 years, were selected from the Chinese fir gene bank in Anhui. Wood core sampling was used to obtain tree ring width and early/latewood width data. Growth rate, fast-growth period, and biomass allocation of each provenance were analyzed using methods such as the logistic growth equation, BAI (basal area increment), latewood percentage, and biomass estimation. The fast-growth period of Chinese fir starts from the 2nd to the 4th year, with significant growth occurring around the 14th year and growth stabilizing between 30 and 50 years. Provenance S2 showed clear advantages in growth rate and biomass, while S6 was relatively weak. BAI analysis revealed that the provenances reached their growth peak around 10 years of age, with a gradual decline afterward, but S2 maintained higher growth levels for a longer period. Root-shoot ratio analysis showed that S2 had the most balanced ratio, promoting stable growth and efficient water and nutrient absorption, while S6 had a higher root-shoot ratio, indicating growth limitations. Furthermore, S2 demonstrated continuous biomass increase after 30 years, indicating excellent growth potential. This study provides quantitative analysis of the growth characteristics and adaptability of different Chinese fir provenances, offering scientific support for the construction and breeding of Chinese fir plantations, and contributing to enhancing the productivity and ecological adaptability of Chinese fir plantations for sustainable resource utilization. Full article

This study investigates the influence of nanocellulose fibre (CF) derived from wood pulp on the hydration, mechanical, shrinkage, and pore properties of ordinary Portland cement (OPC) mortar. The CF was incorporated into mortar mixes at varying dosages (0.15–1.5% by weight of mortar) to evaluate its effect on physical, mechanical, and microstructure properties. X-ray diffraction (XRD), thermogravimetric analysis (TGA/DTG), and mercury intrusion porosimetry (MIP) were employed to assess the hydration phases and microstructural changes induced by the CF addition. Experimental results indicate that CF alters the hydration kinetics of cement mortar by influencing the formation of hydration products such as calcium silicate hydrate (C-S-H), portlandite (CH), and carbonate phases. The introduction of CF enhances crack resistance and shrinkage control, particularly at an optimal dosage of 0.45%, which exhibited reduced drying shrinkage and improved phase stability. While CF incorporation had minimal impact on compressive and flexural strength at lower dosages (≤0.45%), higher CF contents (>0.99%) caused pore structure modifications, leading to an increase in total porosity and a reduction in strength. The XRD analysis revealed that CF does not introduce new hydration phases but modifies the crystallinity of existing phases. The hydration behaviour, as indicated by TGA/DTG, showed an increase in bound water content at moderate CF dosages, suggesting enhanced internal curing and prolonged hydration. Overall, the findings demonstrate that CF is a viable sustainable additive for cementitious materials, offering advantages in shrinkage control, hydration enhancement, and durability improvement. The results suggest that an optimal CF dosage of 0.45% provides a balance between workability, mechanical properties, and durability, making it an effective additive for enhancing the performance of OPC mortars in sustainable construction applications. Full article

Considering the growing need for developing ecological materials, this study investigates the acoustic, mechanical, and thermal properties of wood composites reinforced with beech or oak wood fibres. Scanning electron microscopy (SEM) revealed a complex network of interconnected pores within the composite materials, with varying pore sizes contributing to the material’s overall properties. Acoustic characterization was conducted using a two-microphone impedance tube. The results revealed that the fibre size significantly impacts the sound absorption coefficient, demonstrating that the highest sound absorption coefficient of 0.96 corresponds to the composites reinforced with oak wood fibres with a size of 2 mm in the low-frequency range of 1000–2500 Hz. Mechanical testing revealed a significant reduction in compressive strength as fibre size increased from 0.4 mm to 2 mm, correlating with the observed changes in sound absorption and thermal properties. Thermal analysis indicated thermal conductivity (λ) values ranging from 0.14 to 0.2 W/m·K, with a notable increase in conductivity as fibre size decreased. It was shown that composites reinforced with beech or oak wood fibres with a size of 2 mm are recommendable for insulation materials due to the lowest thermal conductivity of 0.14 W/(m·K). Oak wood composites with a fibre size of 0.4 mm recorded the highest heat capacity, which is 54.4% higher than the one corresponding to the composites reinforced with the largest fibres. The results regarding heat diffusion rates are also reported. The findings about the effects of fibre size and pores on thermal, acoustic and mechanical properties provide valuable insights for designing sustainable materials, offering potential applications in industries where balanced performance across multiple properties is required. Full article

The importance of sustainable innovation in the wood industry is growing, but there is a lack of comprehensive analysis of its evolution, regional differences, and patterns of convergence in China. Based on the panel data of 31 provinces in China from 2011 to 2021, the sustainable innovation index of the wood industry is measured by the projection pursuit method. On this basis, the kernel density estimation method and Dagum Gini coefficient are used to study the dynamic evolution trend, regional differences, and sources of the index, and the convergence characteristics are examined using the coefficient of variation method. The study shows that (1) China’s overall wood industry sustainable innovation index shows a decreasing trend from 2011 to 2021. (2) The differences in the four regions mainly come from inter-regional differences. (3) The index shows significant nonequilibrium characteristics and progressive evolution patterns, and the spatial agglomeration is significant. The magnitude of the index deviation from the average did not decrease over time for the northern and southwestern forest regions. (4) The wood industry sustainable innovation index of the four major forest regions has obviously converged to the same level; under the condition of considering multifactors differentiation, the growth rate of the index of the lower regions is significantly higher than that of the higher regions. The study concludes that current regional imbalances in sustainable innovation in China impede progress and equitable distribution of benefits in the wood industry, and that the impact of regional differences on the β-convergence of sustainable innovation varies according to specific regional characteristics and conditions. These findings provide important theoretical contributions and practical guidance for the development of targeted innovation strategies for the sustainable development of the wood industry, as well as for the promotion of balanced regional development. Full article

Cunninghamia lanceolata (Lamb.) Hook accounts for 12% of the total forest area in southern China, second only to Masson pine forests, and is an important part of the forest landscape in this region, which has a significant impact on the overall forest structure in southern China. In this study, we used kernel density analysis, landscape index calculation, variance test, and Markov prediction to analyze and forecast the evolution trend of landscape pattern in the central area of C. lanceolata in ten years. The objective is to investigate the change trend of the spatial pattern of C. lanceolata landscape in the long time series and its possible impact on zonal vegetation, as well as the macro-succession trend of C. lanceolata under the current social and economic background, and to make a scientific and reasonable prediction of its future succession trend. The current and future forecast results show that the landscape fragmentation degree of C. lanceolata is intensified, the erosion of bamboo forest is continuously intensified, and the landscape quality is continuously low. These results provide a reference for the future development direction of C. lanceolata and emphasize the need for targeted C. lanceolata management strategies in the future development of C. lanceolata, emphasizing the strengthening of monitoring, controlling harvesting, and managing bamboo competition in order to balance wood production with landscape quality and ecosystem stability. Full article

The scarcity of hardwoods from tropical forests makes the search for alternative species necessary for commercialization. This study aimed to establish groups of timber species from the Amazon Forest with potential for logging purposes through the assessment of their physical-mechanical properties, aiming to identify alternative species that can meet the market demands. We utilized data from the Forest Products Laboratory (LPF) (containing information on basic density and other wood mechanical properties) and the Timberflow platform, as well. We applied a multivariate cluster analysis technique with the aim of grouping species based on the technological characteristics of their wood and evaluating similarity among them to obtain homogeneous groups in terms of economic potential and utilization. The results indicated four homogeneous groups: Cluster 1 (40.72% of species, basic density-db: 690 kg m⁻³), Cluster 2 (13.92%, db: 260 and 520 kg m⁻³), Cluster 3 (27.32%, db: 550 and 830 kg m⁻³), and Cluster 4 (18.04%, db: 830 kg m⁻³). Most of the 20 listed species are classified as more commercially viable (70%), with high wood density. Species identified as alternatives include Dialium guianense and Zollernia paraensis for Dipteryx odorata, Terminalia argentea for Dinizia excelsa, Terminalia amazonia and Buchenavia grandis for Goupia glabra, and Protium altissimum and Maclura tinctoria for Hymenaea courbaril. The analysis highlighted the overexploitation of a restricted group of species and the need to find alternatives to ensure the sustainability of forest management. This study contributed to identifying species that can serve as alternatives to commercial ones, promoting a more balanced and sustainable forest management. Full article

Juglans regia L. is an edible fruit tree cultivated worldwide for its fruits and wood and as an urban tree. Globally, there is growing concern for preserving the genetic diversity of trees with high economic and ecological value. This study investigates the genetic diversity of J. regia in urban landscapes and assesses the quality of its walnut kernels as a local food product. An inventory of 150 trees from five populations in public green spaces in Lugoj, Caransebeș and Jupa, as well as two semi-natural hilly ecosystems in the Banat Region, was conducted. Molecular analyses showed that Directed Amplification of Minisatellite-region DNA (DAMD) markers were more effective than Start Codon Targeted (SCoT) markers, with a higher average polymorphism of 56.26%, compared to 49.44%. DAMD07 achieved 100% polymorphism and DAMD05 showed a strong balance between P.I.C. (0.35) and polymorphism (54.54%). Chemical analysis revealed the following contents in walnut kernels: protein (12.81% to 16.80%), lipids (60.39% to 69.08%), total polyphenols (5484.66 to 10,788.4 mg GAE/kg), copper (3.655 to 8.532 mg/kg), manganese (14.408 to 28.618 mg/kg), zinc (19.813 to 46.583 mg/kg), lead (1.204 to 2.27 mg/kg) and cadmium (0.03451 to 0.08065 mg/kg). These findings are critical for conservation efforts, urban forestry management and ensuring the quality and safety of walnut products derived from J. regia. Full article

Tissue homeostasis, function recovery, and protection mechanisms are boosted by the balanced and timely control of inflammation and oxidative stress. Nowadays, many natural products and bio-derivates exhibit antioxidant and anti-inflammatory activity, supporting medical care and tissue wellness against inflammation, oxidative stress, and inflammaging. Castanea sativa wood distillate (WD) is a bio-derivative used as a corroborant and biofertilizer in agriculture. Based on the safety profile of low concentrations of WD on human cells, the present study aims to assess the anti-inflammatory and antioxidant activity of WD on different cell types in the integumentary system. Human keratinocytes, mucosal epithelium, dermal fibroblasts, and endothelial cells were exposed to WD, and the concentrations devoid of pro-apoptotic potential were profiled. Then, the effect of nontoxic doses of WD revealed an anti-inflammatory effect, observed through the immunodetection of prostanoid cascade markers in experimentally induced inflammation. A reduction in endothelial hyperpermeability was evidenced by the immunofluorescence analysis of cell–cell adhesion proteins, VE-cadherin and ZO-1. In addition, WD buffered the exogenously produced oxidative stress. On the whole, WD showed both anti-inflammatory and antioxidant activities on the various cell types, preserving endothelial barrier integrity. Overall, this study supports the involvement of this bio-derivative in novel exploitable fields, such as therapeutic dermatological applications for human and animal medical care. Full article

Oak is one of the most economically important hardwood tree species in Europe, and its prevalence will increase due to progressing global climate change, according to predictive models. With the increasing demand for timber and with the need for a balance between carbon emissions and sequestration, it is essential to address the afforestation of agricultural land. Therefore, this research aimed to investigate the physico-mechanical properties and anatomical structure of pendulate oak (Quercus robur L.) wood—specifically focusing on the trunk’s cross-section—in post-agricultural areas compared with the forest land in the western part of Poland. Wood density, bending strength, modulus of elasticity, and other parameters were analyzed from 1626 wood samples. The analysis of physico-mechanical properties reveals that, historically, agricultural land use has an almost negligible impact on wood quality. Despite significant differences in small vessel diameter and fiber length favoring trees from post-agricultural land, the physico-mechanical properties remain consistent. Large vessel measurements show comparable diameter and length in both land types. These findings suggest that post-agricultural land can serve as an effective alternative for high-quality pendulate oak wood production for industrial purposes. However, wood from post-agricultural land may exhibit a decrease in modulus of rupture by over 30% and potentially lower density above the trunk’s halfway point. This observation hints at the fact that oak trees in post-agricultural areas could be cultivated in shorter rotation periods compared to forest land. Full article