Search Results (112)

Environmental degradation and soil desertification are among the most severe environmental issues of recent decades worldwide. Over time, these processes have led to increasingly extreme and highly dynamic climatic conditions. In Brazil, the Northeast Region is characterized by semi-arid and arid areas that exhibit high climatic variability and are extremely vulnerable to environmental changes and pressures from human activities. The application of geotechnologies and geographic information system (GIS) modeling is essential to mitigate the impacts and pressures on the various ecosystems of Northeastern Brazil (NEB), where the Caatinga biome is predominant and critically threatened by these factors. In this context, the objective was to map and assess the spatiotemporal patterns of land use and land cover (LULC), detecting significant trends of loss and gain, based on surface reflectance data and precipitation data over two decades (2000–2019). Remote sensing datasets were utilized, including Landsat satellite data (LULC data), MODIS sensor data (surface reflectance product) and TRMM data (precipitation data). The Google Earth Engine (GEE) software was used to process orbital images and determine surface albedo and acquisition of the LULC dataset. Satellite data were subjected to multivariate analysis, descriptive statistics, dispersion and variability assessments. The results indicated a significant loss trend over the time series (2000–2019) for forest areas (Z_MK = −5.872; Tau = −0.958; p < 0.01) with an annual loss of −3705.853 km² and a total loss of −74,117.06 km². Conversely, farming areas (agriculture and pasture) exhibited a significant gain trend (Z_MK = 5.807; Tau = 0.947; p < 0.01), with an annual gain of +3978.898 km² and a total gain of +79,577.96 km², indicating a substantial expansion of these areas over time. However, it is important to emphasize that deforestation of the region’s native vegetation contributes to reduced water production and availability. The trend analysis identified an increase in environmental degradation due to the rapid expansion of land use. LULC and albedo data confirmed the intensification of deforestation in the Northern, Northwestern, Southern and Southeastern regions of NEB. The Northwestern region was the most directly impacted by this increase due to anthropogenic pressures. Over two decades (2000–2019), forested areas in the NEB lost approximately 80.000 km². Principal component analysis (PCA) identified a significant cumulative variance of 87.15%. It is concluded, then, that the spatiotemporal relationship between biophysical conditions and regional climate helps us to understand and evaluate the impacts and environmental dynamics, especially of the vegetation cover of the NEB. Full article

As industries continue to prioritize sustainability and resource efficiency, Paulownia stands out as a sustainable candidate for replacing Balsa in engineered wood products, offering a lighter, cost-effective solution with the added benefit of reduced ecological impact. The aim of this research is to manufacture 7 mm- and 15 mm-thick plywood from Paulownia tomentosa x elongata veneers (as an alternative for balsa veneers) using polyurethane (PUR) and melamine–urea–formaldehyde (MUF) adhesives, and to analyze their physical and mechanical properties. Panels with five and seven layers and thicknesses from 0.8 to 3 mm were tested for bulk density (247–385 kg/m³), thickness swelling (2.47%–5.34%), and water absorption (35%–68%) according to European standards. Mechanical properties assessed included three-point bending strength (MOR) parallel (22–35.8 N/mm²) and perpendicular to the fiber/grain (13.4–21.8 N/mm²), three-point modulus of elasticity (MOE) in longitudinal (2824–3799 N/mm²) and transverse directions (1183–1825 N/mm²), tensile shear strength (1.76–2.52 N/mm²), and screw withdrawal resistance (41.9–60.6 N/mm). Results indicate that Paulownia plywood has significant potential for lightweight construction due to its low density and favorable properties, with MUF adhesive showing superior performance in terms of density and panel properties. This positions Paulownia plywood as a strong contender in the ongoing evolution of lightweight construction materials. Full article

This work aims to investigate the buckling and post-buckling behaviour of wood-based sandwich structures with and without a manufacturing defect, under compressive loading. The specimens were made by gluing birch veneers to a balsa wood core. The defect consisted of a central zone where glue was lacking between the skin and the core. A compression load was applied to the plate using the VERTEX test rig, with the plate placed on the upper surface of a rectangular box and bolted at its borders. The upper surface of the plate was monitored using optical and infrared cameras. The stereo digital image correlation method was used to capture the in-plane and out-of-plane deformations of the specimen, and to calculate the strains and stresses. The infrared camera enabled the failure scenario to be identified. The buckling behaviour of pristine specimens showed small local debonding in the post-buckling range, which was not detrimental to overall performance. In the presence of a manufacturing defect, the decrease in buckling load was only about 15%, but final failure occurred at lower compressive loads. Full article

Ochroma lagopus, a fast-growing tropical tree species, faces fertilization challenges due to slope heterogeneity in plantations. This study examined 3-year-old Ochroma lagopus at upper and lower slope positions under five treatments: CK (no fertilizer), F1 (600 g/plant), F2 (800 g/plant), F3 (1000 g/plant), and F4 (1200 g/plant) of secondary macronutrient water-soluble fertilizer. Growth parameters and N-P-K stoichiometry were analyzed. Key results: (1) Height increased continuously with fertilizer dosage at both slopes, while DBH peaked and then declined. (2) At upper slopes (nutrient-poor soil), fertilization elevated leaf P but reduced branch N/K and increased root P/K. At lower slopes (nutrient-rich soil), late-stage leaf N increased significantly, with roots accumulating P/K via a “storage strategy”. Stoichiometric thresholds indicated N-K co-limitation (early-mid stage) shifting to P limitation (late stage) on upper slopes and persistent N-K co-limitation on lower slopes. (3) PCA identified F4 (1200 g/plant) and F1 (600 g/plant) as optimal for upper and lower slopes, respectively. This research provides a theoretical basis for precision fertilization in Ochroma lagopus plantations, emphasizing slope-specific nutrient status and element interactions for dosage optimization. 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

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

The presence of tetracycline hydrochloride (TC) in the environment poses significant risks to human health and ecological stability, necessitating the development of effective and rapid removal strategies. In this research, we investigate the efficacy of degrading tetracycline hydrochloride using cobalt-doped-biochar (Co-BC)-activated peroxymonosulfate (PMS) and the underlying mechanisms of this process. The research objectives and conclusions were as follows: (1) Co-BC materials were synthesized from balsa wood powder through a process of impregnation followed by high-temperature calcination. Characterization techniques such as SEM, XRD, FTIR, and XPS were used to confirm the material’s structure and composition. (2) In a TC solution of 20 mg L⁻¹, the use of 100.0 mg L⁻¹ of Co-BC and 1.0 mM PMS led to a TC degradation efficiency of 96.2% within 30 min. (3) The Co-BC+PMS system exhibited wide pH adaptability (4.34–9.02) and strong resistance to environmental matrix interference (Cl⁻, ${\mathrm{NO}}_3^{-}$, and ${\mathrm{SO}}_4^{2-}$). (4) Free-radical quenching experiments indicated that sulfate radicals ($\mathrm{S}{\mathrm{O}}_4^{•-}$) were the primary reactive species in TC degradation. The 11 intermediates of TC were analyzed using LC-MS, and two possible degradation pathways were deduced. In summary, this study offers significant, valuable insights into and technical support for the green, efficient, and environmentally friendly removal of antibiotics from sewage. Full article

Wood-based membranes have garnered increasing attention due to their structural advantages and durability in the efficient treatment of oily kitchen wastewater. However, conventional fabrication methods often rely on toxic chemicals or synthetic processes, generating secondary pollutants and suffering from fouling, which reduces performance and increases resource loss. In this study, an innovative bilayer membrane was developed from balsa wood by combining a hydrophilic longitudinal layer for water transport with a polydimethylsiloxane (PDMS)-impregnated carbonized transverse layer to enhance hydrophobicity, resulting in increased separation efficiency and a reduction in fouling by 98.38%. The results show a high permeation flux of 1176.86 Lm^–2 h^–1 and a separation efficiency of 98.60%, maintaining low fouling resistance (<3%) over 20 cycles. Mechanical tests revealed a tensile strength of 10.92 MPa and a fracture elongation of 10.42%, ensuring robust mechanical properties. Wettability measurements indicate a 144° contact angle and a 7° sliding angle with water on the carbonized side, and a 163.7° contact angle with oil underwater and a 5° sliding angle on the hydrophilic side, demonstrating excellent selective wettability. This study demonstrates the potential of carbonized wood-based membranes as a sustainable, effective alternative for large-scale wastewater treatment. Full article

Background/Objectives: Rheumatoid arthritis (RA) and osteoarthritis (OA) are highly prevalent diseases and their pathophysiology, diagnosis and treatment continue to be challenging. The aim of this study was to characterize and differentiate the profiles of the serum extracellular vesicles (EVs) isolated from RA and OA patients. Methods: This study included nine patients diagnosed with RA, eight patients with OA during a flare and five healthy controls (HCs). Blood samples were collected and EVs from the serum were isolated for further performance of flow cytometry and proteomic analysis. Results: The extracellular vesicles from HC samples exhibited smaller sizes and were more concentrated than exosomes from RA and OA samples. Surface protein expression was analyzed by flow cytometry. The results showed an enrichment of exosomes derived from antigen-presenting cells in RA samples; this was evidenced by their expression of CD14 and HLA-DR. Proteomic analysis identified 45 differentially expressed proteins between RA and OA patients. Furthermore, Ingenuity Pathway Analysis (IPA) identified inflammatory pathways such as the IL-1β and IL-6 signaling pathways as being enhanced in RA-derived exosomes, while the MYC and ROCK2 signaling pathways were enhanced in OA-derived exosomes. Conclusions: Our results show serum-derived exosomes from RA and OA patients harbor different surface proteins and cargo profiles, mirroring the different pathophysiologic mechanisms underlying these diseases. These results also highlight the promising use of exosomes as disease biomarkers. Full article

To address the need for reducing carbon emissions and enhancing the sustainable utilization of non-fossil resources, a one-step calcination strategy has been developed to fabricate hierarchical carbon aerogels from balsa wood. The resulting wood-derived carbon aerogels (WCA) were functionalized with Mg(OH)₂ to boost their environmental remediation potential. Comprehensive characterization using XRD, FT-IR, XPS, and SEM confirmed that the optimized WCA/Mg(OH)₂ composite (WCAMg) retained a three-dimensional hierarchical porous structure, and Mg(OH)₂ nanosheets were attached to it. The adsorption performance of WCAMg composites towards Cd²⁺ was systematically investigated through controlled experiments, which focused on three critical variables (Mg(OH)₂ loading content, initial Cd²⁺ concentration and solution ionic strength). The functionalized WCAMg demonstrated a maximum Cd²⁺ adsorption capacity of 351.1 mg g⁻¹—a tenfold improvement over pristine WCA. Combined with exceptional adsorption efficiency, this biomass-derived composite offers an eco-friendly, cost-effective solution for heavy metal ion remediation. Its scalable fabrication from renewable resources aligns with sustainable water treatment objectives, presenting the advantage of pollution mitigation. Full article

Yeast batch fermentation is widely used in industrial biotechnology, yet its performance is strongly influenced by temperature and nitrogen availability, which affect growth kinetics and metabolite production. The development of predictive models that accurately describe these effects is essential for automating and optimizing fermentation design, reducing trial-and-error experimentation, and improving process efficiency and product quality. However, most mathematical models focus on primary metabolism and lack a systematic approach to integrate the effects of temperature. Existing models often rely on empirical corrections with limited predictive power beyond specific experimental conditions. Furthermore, there is no unified framework for optimizing fermentation processes while accounting for the temperature-dependent metabolic responses. We addressed these gaps by developing a temperature-dependent kinetic model for nitrogen-limited batch fermentation by Saccharomyces cerevisiae. The modeling approach is based on advanced systems identification, integrating identifiability analyses (structural and practical), multi-experiment parameter estimation, and automated model selection to determine the most appropriate temperature dependencies for key metabolic processes. Validated across five industrial S. cerevisiae strains in an illustrative example related to wine fermentation, the model exhibited strong predictive performance (NRMSE $<10.5\%$, median R²$>0.95$) and enabled simulation-based process optimization, including nitrogen-supplementation strategies and strain selection for improved fermentation outcomes. By providing a systematic modeling framework that accounts for temperature effects, this work bridges a critical gap in predictive modeling and advances the rational design and control of industrial fermentation processes. Full article

The growing demand for sustainable composites has increased interest in natural fiber reinforcements as alternatives to synthetic materials. This study evaluates the bending properties of sandwich structures with flax fibers and 3D-printed lightweight foaming PLA cores compared to conventional designs using glass fibers and traditional cores. Three-point bending tests (EN 310) and density profile analysis showed that, despite its lower density, the 3D-printed foaming PLA core achieved a modulus of elasticity of 2269.19 MPa and a bending strength of 31.46 MPa, demonstrating its potential for lightweight applications. However, natural fibers influenced resin absorption, affecting core saturation compared to glass fibers. The use of bio-based epoxy and foaming PLA contributes to a lower environmental footprint, while 3D printing enables precise material optimization. These findings confirm that 3D-printed cores offer a competitive and sustainable alternative, with future research focusing on further optimization of internal structure to enhance mechanical performance. Full article

Anthropic activities such as agriculture, livestock, and wastewater discharges affect water quality in the Tlapaneco River in the mountain region of the state of Guerrero, México, which is a tributary of the Balsas. The river flows from the mountain region and discharges into the Pacific Ocean; the water resource in the localities mentioned is used for agriculture, recreation, and domestic activities. The aim of this study was to evaluate water quality in the stretch of influence of two localities, Patlicha and Copanatoyac. The instrument used was the Biological Monitoring Working Party biotic index (BMWP) and physicochemical parameters. Nine sampling sites were selected according to the perception of the local community with respect to disturbance; the study area was divided into three parts: high, medium, and low. Twenty-seven collections of macroinvertebrates and water were analyzed, in dry and rainy seasons, through the presence–absence of these organisms and physicochemical analysis, to evaluate water quality. The results showed that the conditions of the riverbed associated with daily activities and domestic discharges are important factors in the composition of the families. Water quality was very poor to regular, according to the macroinvertebrate assemblages collected. The BMWP index was of acceptable quality when the orders (Family) Ephemeroptera (Leptohyphidae; Leptophlebiidae; Baetidae; Ephemerellidae), Diptera (Chironomidae; Simulidae), Trichoptera (Hydropsychidae), Hemiptera (Veliidae; Corixidae), Coleoptera (Hydrophylidae), and Odonata (Lestidae) were present; in sites with poor quality, the families Chironomidae, Leptophlebiidae, Veliidae, Corixidae, Hydropsychidae, Leptohyphidae, Hydrophilidae, Baetidae, and Simuliidae were found, while in very poor quality water, only family Corixidae was present. Full article

Gaseous oxygen detection is essential in numerous production and manufacturing sectors. To meet the varying oxygen detection requirements across different fields, techniques that offer a wide oxygen detection range should be developed. In this study, a wood-based oxygen sensing material was designed using balsa wood as the supporting matrix and gadolinium hemoporphyrin monomethyl ether (Gd-HMME) as the oxygen-sensitive indicator. The wood-based Gd-HMME exhibits a cellular porous structure, which not only facilitates the loading of a substantial number of indicator molecules but also enables the rapid interaction between indicators and oxygen molecules. OP is defined as the ratio of the phosphorescence intensity of the oxygen-sensing material in the anaerobic and aerobic environment. A linear relationship between OP and oxygen partial pressure ([O₂]) was obtained within the whole range of [O₂] (0–100 kPa). The wood-based Gd-HMME exhibited excellent resistance to photobleaching, along with a rapid response time (3.9 s) and recovery time (4.4 s). It was demonstrated that the measurement results obtained using wood-based Gd-HMME were not influenced by other gaseous components present in the air. An automatic oxygen detection system was developed using LabVIEW for practical use, and the limit of detection was determined to be 0.01 kPa. Full article

Interlayered composites with three types of cores were fabricated and tested. Quasi-static penetration tests (QSPTs), bending tests, and impact tests were conducted on the fabricated composites with carbon fiber epoxy laminate facings. Penetration test procedures were carried out until the composite was perforated and completely punctured. A 9 mm diameter rounded-tip punch was used; the diameter of the support hole was 45 mm. To determine the mechanical properties in the bending tests, three-point bending was carried out at a speed of 2 mm/min. Impact tests were also carried out using a Charpy impact test and a hammer with an energy of 2 J. Our findings indicate that the core material plays a crucial role in determining a composite’s mechanical behavior. Balsa cores offer the best properties in the QSPT test and bending strength and stiffness (57 MPa and 7.4 GPa, respectively), while Rohacell^® cores provide excellent impact resistance (12 kJ/m²). Nomex^® cores demonstrate high bending stiffness (5.3 GPa) but perform worse than Balsa. The choice of core material is application-dependent; Balsa cores are optimal for bending and point loads, and Rohacell^® cores are optimal for impact-dominated scenarios. Full article