Search Results (148)

Reinforced concrete is currently the most widely used system in the construction industry due to its excellent properties, including its durability, workability, lifetime, and compressive strength. However, reinforced concrete structures have disadvantages, such as corrosion, that affect their performance and may even lead to unexpected and/or premature failures. The main cause of this type of failure is the presence of chlorides, mostly from seawater. In this context, cathodic protection is one of the most efficient methods for protecting reinforced steel from corrosion. However, it is very expensive due to the high resistivity of concrete. In this research work, it is proposed to modify concrete by partially replacing the fine aggregate with rPET and CBF, thus exploiting the mechanical properties of rPET to promote energy dissipation, mitigating the stresses to which the reinforced concrete system is exposed and increasing its compressive strength. Furthermore, due to its hygroscopicity, CBF is used to promote moisture retention and reduce the resistivity of the concrete, thus facilitating cathodic protection of the reinforcing steel through the impressed current. The results indicate that the presence of rPET increases the compressive strength of concrete by approximately 8% in comparison with the reference sample after 28 days of curing, while the presence of CBF reduces the resistivity of concrete, ultimately increasing the cathodic protection efficiency of the reinforcing steel. Full article

Volcanic Scoria Lightweight Aggregate Concrete (VSLAC) has been identified as a material with considerable potential for use in carbon-neutral construction; however, its application is often hindered by two main issues. Firstly, the low density of scoria often results in aggregate segregation and stratification. Secondly, its high hygroscopicity can lead to shrinkage cracking. In order to address the aforementioned issues, this study proposes a multi-scale modification strategy. The cementitious matrix was first strengthened using a binary blend of Fly Ash and Ground Granulated Blast Furnace Slag (GGBS), followed by the incorporation of a ternary admixture system containing Styrene-Acrylic Emulsion (SAE), a foaming agent (FA), and alkali-treated Straw Fibres (SF) to enhance workability and durability. The findings of this study demonstrate that a mineral admixture comprising 10% Fly Ash and 10% GGBS results in a substantial enhancement of matrix compactness, culminating in a 20% increase in compressive strength. An orthogonal test was conducted to identify the optimal formulation (D13), which was found to contain 4% SAE, 0.1% FA, and 5% SF. This formulation yielded a compressive strength of 35.2 MPa, a flexural strength of 7.5 MPa, and reduced water absorption to 8.0%. A comparative analysis was conducted between the mineral admixture mix ratio (Control group) and the Optimal mix ratio (Optimization group). The results of this analysis reveal that the Optimization group exhibited superior durability and thermal characteristics. Specifically, the water penetration depth of the optimized composite was successfully restricted to within 3.18 mm, while its thermal insulation performance demonstrated a significant enhancement of 12.3%. In the context of freeze–thaw cycles, the modified concrete demonstrated notable durability, exhibiting a 51.4% reduction in strength loss and a marginal 0.64% restriction in mass loss. SEM analysis revealed that the interaction between SAE and the FA resulted in the densification of the Interfacial Transition Zone (ITZ). In addition, the 3D network formed by SF redistributed internal stresses, thereby shifting the failure mode from brittle fracture to ductile deformation. The findings demonstrate that modifying VSLAC at both micro- and macro-levels can effectively balance structural integrity with thermal efficiency for sustainable construction applications. Full article

The combination of nanogenerator technology and traditional textile materials has given rise to textile-based triboelectric nanogenerators (T-TENGs) structured from fibers, yarns, and fabrics. Due to their lightweight, flexibility, washability, and cost-effectiveness, T-TENGs offer a promising platform for powering and sensing in next-generation wearable electronics, with particularly significant potential in smart healthcare and sports monitoring. However, the inherent electrical and structural limitations of textile materials often restrict their power output, signal stability, and sensing range, making it challenging to achieve both high electrical performance and high sensing sensitivity. This review focuses on the application of T-TENGs in smart healthcare and sports. It systematically presents recent developments in textile material selection, sensing structure, fabric design, working mechanisms, accuracy optimization, and practical application scenarios. Furthermore, it provides a critical analysis of the recurring structural and material limitations that constrain performance and offers constructive pathways to address them. Key challenges such as the low charge density of textile interfaces may be mitigated by selecting low-hygroscopicity materials, applying hydrophobic treatments, and optimizing textile structures to enhance contact efficiency and environmental stability. Issues of signal instability under dynamic deformation call for advanced structural designs that accommodate strain without compromising electrical pathways, coupled with robust signal processing algorithms. By providing a comparative analysis across materials and structures, this review aims to inform future designs and accelerate the translation of high-performance T-TENGs from laboratory research to real-world implementation. Full article

This preliminary study investigates a direct, non-delaminated route to valorize multilayer pharmaceutical sachet offcuts (comprising paper/plastic/aluminum) as partial substitutes for wood fiber in wood-based panels. Milled offcuts were incorporated at 10, 20, and 30 wt% (control: wood only). Laboratory mats were hot-pressed at 170 °C for 9 min under a staged pressure regime. Sampling and three-point bending were performed according to EN 326-1 and EN 310, respectively, with the density held essentially constant by controlling the mat mass and press stops. Bending stiffness (MOE) was maintained at 10–20 wt% (within experimental uncertainty of the reference), while 30 wt% showed a consistent downward trend (approximately 10%). Bending strength (MOR) peaked at 10 wt% (approximately 8% higher than the reference), then declined at 20% and 30%. Representative stress–strain curves corroborated these outcomes, indicating auxiliary bonding and crack-bridging effects at low waste loadings. Hygroscopic performance improved monotonically: 24 h water absorption and thickness swelling decreased progressively with increasing substitution, attributable to the hydrophobic polymer layers and aluminum fragments interrupting capillary pathways. Process observations identified opportunities to improve press-cycle efficiency at higher waste contents, and the dispersed foil imparted a subtle decorative sheen. Overall, the results establish the technical feasibility and a practical utilization window of approximately 10–20 wt% for furniture-grade applications. Limitations include the laboratory scale, a single resin/press schedule, and the absence of internal bond, density profile, emissions, and long-term durability tests—topics prioritized for future work (including TGA/DSC, EN 317 extensions, and scale-up). Full article

Warm-cloud hygroscopic seeding is widely used in precipitation enhancement, but the conditions under which seeding amplifies or suppresses rainfall remain unclear. Here, we use a two-dimensional slab-symmetric spectral bin microphysics model from Tel Aviv University to simulate a warm convective cloud that occurred over Hainan, China, on 11 May 2024, and design three sets of sensitivity experiments in which hygroscopic particles of different characteristic diameters are introduced under a fixed-mass injection constraint. We find that seeding with submicrometer particles (0.1–0.9 µm) systematically suppresses precipitation, with the strongest reduction for 0.1 µm particles. When super-micrometer particles (1–9 µm) are used, the precipitation response transitions from suppression to enhancement as particle size increases, and this transition occurs at about 2 µm. Seeding with ultra-giant particles (>10 µm) generally enhances rainfall and also advances its onset, with the enhancement strengthening up to ~60 µm before weakening for even larger particles. We further show that the transitional particle size at which the seeding effect changes sign decreases with increasing background aerosol loading, from maritime to polluted urban conditions. These results identify an environment-dependent critical particle size that governs the sign and efficiency of hygroscopic seeding in warm convective clouds. Full article

As an eco-friendly natural building material, rammed earth possesses outstanding hygrothermal performance, which plays a vital role in achieving the goals of sustainable architecture. However, most existing simulations assume constant hygrothermal parameters, resulting in considerable discrepancies between predicted and actual energy performance and consequently underestimating the true passive regulatory potential of rammed earth. To enhance the accuracy of energy consumption predictions in rammed earth buildings, this study integrates experimental measurements with dynamic simulations and experimentally determines both the constant and non-constant hygrothermal parameters of rammed earth. By integrating experimental and simulation approaches, this study reveals a strong positive linear correlation between the thermal conductivity of rammed earth and its moisture content (R² = 0.9919), increasing from 0.77 W/(m·K) to 1.38 W/(m·K) as moisture content rises from 0% to 14%, whereas the moisture resistance factor decreases exponentially with increasing relative humidity (RH). Subsequently, the two sets of hygrothermal parameters were implemented in the WUFI-Plus simulation platform to conduct annual dynamic simulations across five representative Chinese climate zones (Harbin, Beijing, Nanjing, Guangzhou, and Dali), systematically comparing the performance differences between the “non-constant” and “constant” parameter models. The results show that the non-constant parameter model effectively captures the dynamic hygrothermal regulation of rammed earth, exhibiting superior passive performance. It predicts substantially lower building energy loads, with heating energy reductions most pronounced in Harbin and Beijing (16.9% and 15.5%) and cooling energy reductions most significant in Guangzhou and Nanjing (15.8% and 15.2%). This study confirms that accurately accounting for the dynamic hygrothermal coupling process is fundamental to reliably evaluating the performance of hygroscopic materials such as rammed earth, providing a robust scientific basis for promoting energy-efficient, low-carbon, and climate-responsive sustainable building design. Full article

Reliable water vapor permeability (WVP) testing is crucial for sustainable construction, enabling accurate assessment of bio-mineral materials like hemp concrete, which reduce the environmental impact through renewable sourcing and improved energy efficiency. However, most studies testing or conditioning porous building materials in environmental chambers overlook the influence of chamber occupancy on airflow and humidity evacuation. While the usual practice is to collect anemometric velocity results in selected locations, few investigations apply computational fluid dynamics (CFD) to analyze the entire flow field, and humidity-field assessment is practically absent. This study addresses this gap by using CFD to examine how sample arrangement affects airflow and relative humidity (RH) in a climatic chamber containing sixteen hemp concrete specimens in dry- and wet-cup setups, aiding the reliable characterization of hygroscopic eco-composites. Three arrangements were modeled in ANSYS Fluent (2024 R1) using turbulence and species transport. Results show that unoptimized wet-cup placements cause RH deviations exceeding ISO’s ±5% tolerance, potentially biasing permeability data and undermining comparability across laboratories. A balanced wet–dry layout maintained RH within limits, improving testing reproducibility. Velocity maps reveal strong gradients above exposed sample surfaces, suggesting that standard anemometric protocols may require refinement. The presented approach highlights chamber loading as a hidden factor influencing WVP results and provides a transferable CFD-based framework to enhance testing accuracy, support sustainable material qualification, and accelerate the standardization of green-building methodologies. Full article

Sustainable construction requires bio-based insulation materials that achieve low thermal conductivity without compromising mechanical performance. Poplar wood, which is locally abundant in France, serves as an effective carbon sink and represents a promising resource. While recent research has explored bulk wood delignification, the characterization of such modified materials remains insufficient for practical implementation. In this work, we report the development of gradient-delignified poplar wood through partial delignification using alcoholysis and sodium chlorite bleaching. This process produced a hybrid structure with delignified outer layers and a lignified core. Microscopic analyses revealed that lignin removal led to cell wall swelling and the formation of nano-scale pores. Compared to native poplar, the modified material showed lower transverse thermal conductivity (0.057 W·m⁻¹·K⁻¹), higher specific heat capacity (1.4 kJ·K⁻¹·kg⁻¹ at 20 °C), increased hygroscopicity, and reduced longitudinal compressive strength (15.9 MPa). The retention of the lignified core preserved dimensional stability and load-bearing capacity, thereby overcoming the limitations of complete delignification. In contrast to synthetic foams or mineral wools, these findings demonstrate that partial delignification can produce anisotropic wood-based insulation materials that combine thermal efficiency, mechanical stability, and biodegradability. This work highlights the potential of wood modification nanotechnology to reduce the carbon footprint of building materials. Full article

This review synthesizes recent research on alternative fuels for piston-engine aircraft and related propulsion technologies. Biofuels show substantial promise but face technological, economic, and regulatory barriers to widespread adoption. Among liquid options, biodiesel offers a high cetane number and strong lubricity yet suffers from poor low-temperature flow and reduced combustion efficiency. Alcohol fuels (bioethanol, biomethanol) provide high octane numbers suited to high-compression engines but are limited by hygroscopicity and phase-separation risks. Higher-alcohols (biobutanol, biopropanol) combine favorable heating values with stable combustion and emerge as particularly promising candidates. Biokerosene closely matches conventional aviation kerosene and can function as a drop-in fuel with minimal engine modifications. Emissions outcomes are mixed across studies: certain biofuels reduce NO_x or CO, while others elevate CO₂ and HC, underscoring the need to optimize combustion and advance second- to fourth-generation biofuel production pathways. Beyond biofuels, hydrogen engines and hybrid-electric systems offer compelling routes to lower emissions and improved efficiency, though they require new infrastructure, certification frameworks, and cost reductions. Demonstrated test flights with biofuels, synthetic fuels, and hydrogen confirm technical feasibility. Overall, no single option fully replaces aviation gasoline today; instead, a combined trajectory—biofuels alongside hydrogen and hybrid-electric propulsion—defines a pragmatic medium- to long-term pathway for decarbonizing general aviation. Full article

Artemisia herba-alba Asso. is a medicinal plant rich in phenolic compounds with strong antioxidant and antimicrobial activities. However, these bioactive molecules are highly sensitive to environmental conditions, limiting their stability and potential applications. This study investigated, for the first time, the encapsulation of ethanolic extracts from the aerial parts of A. herba-alba by spray-drying, using maltodextrin (MD) and sodium caseinate (SC) as wall materials. The extract was obtained by ultrasound-assisted extraction, and both free and encapsulated forms were analyzed for phytochemical composition, antioxidant capacity, and antibacterial activity. Spray-dried microcapsules (SDE) were further characterized for encapsulation yield, efficiency, moisture, water activity, hygroscopicity, particle size, and structural integrity (SEM, ATR-FTIR, TGA/DTG). The process resulted in a high encapsulation yield (69.40%) and efficiency (96.39%), producing microcapsules with a small average size (10.05 ± 0.08 µm), low moisture (4.34%), low water activity (0.415), and moderate hygroscopicity (12.67%). Although the encapsulated extract showed lower total phenolic content, antioxidant capacity, and antibacterial activity compared to the free extract, SEM observations confirmed the formation of spherical, crack-free microcapsules, ATR-FTIR analysis revealed non-covalent interactions between wall materials and phenolics, and TGA/DTG demonstrated improved thermal stability. These results highlight spray-drying microencapsulation as an efficient approach to stabilize A. herba-alba phenolic compounds, offering promising applications as natural preservatives in the food industry. Full article

Bamboo is a lignocellulosic material characterized by its high hygroscopicity, which refers to the ability of material to absorb and retain moisture from the surrounding environment. This attribute could adversely affect its dimensional stability and resistance against deterioration agents. Thus, a study was conducted to investigate the effect of thermal modification on the hygroscopic, mechanical, and chemical properties of three-year-old Gigantochloa scortechinii, a native and highly exploited bamboo species in Malaysia. Overall, heat treatment effectively reduced the equilibrium moisture content and improved the dimensional stability of bamboo, with samples treated at 210 °C exhibited the most significant moisture resistance of up to 95.6% anti-swelling efficiency (ASE). The heat-treated bamboo exhibited an improvement in modulus of elasticity (MOE) at intermediate temperatures (170–190 °C) whereas modulus of rupture (MOR) declined at 210 °C. Chemical analysis indicated that a significant reduction in hemicellulose content and a relative increase in α-cellulose and lignin contributed to the improved moisture resistance of heat-treated bamboo. The results demonstrate the viability of heat treatment in producing quality thermally modified bamboo as an alternative raw material for construction materials and furniture manufacturing, thereby contributing to the development of Malaysia’s bamboo industry. Full article

This study explored the use of Borassus fruit fiber as reinforcement for earthen matrices (BFRC). The experimental results of the testing carried out on the structural properties were used to generate a primary dataset for training and testing machine learning (ML) models. Linear regression (LR), Decision tree regressor (DTR), and gradient boosting regression (GBR) were used to build an ensemble learning (EL) model during the prediction of the hygroscopic properties, Young’s modulus, and compressive strength of the BFRC. Fiber content, activation concentration, curing days, dry weight, saturated weight, mass, flexural vibration, longitudinal vibration, correction factor, maximum load, and cross-sectional area were the various inputs considered in the structural properties prediction. The performance of both EL and single models (SMs) was appraised via three performance metrics—mean square error (MSE), root mean square (RMSE), and the coefficient of determination (R²)—to comparatively ascertain the model’s efficiency. Results showed that all models exhibited high accuracy in predicting Young’s modulus and compressive strength. Ensemble learning outperformed single models in predicting these properties, with MSE, RMSE, and R² of 0.01 MPa, 0.1 MPa, and 99% and 3,923,262.5 MPa, 1980.7 Pa, and 99% for compressive strength and Young’s modulus, respectively. However, for hygroscopic behavior, linear regression (LR) demonstrated superior performance compared to other models, with MSE, RMSE, and R² values of 0.13%, 0.36%, and 99%. Full article

Aluminum powder has the advantages of high calorific value, high density and convenient source, and is a commonly used metal fuel in the explosives and propellants industry. Nanometer aluminum powder (nAl) has higher reactivity and higher reaction completeness than micron aluminum powder (μAl), which can improve the energy performance of mixed explosives and the burning rate of propellant. However, nAl has some disadvantages, such as easy oxidation and deterioration of the preparation process, which seriously affect its application efficiency. In order to improve these shortcomings, suitable surface coating treatment is needed. The effects of surface coating on the characteristics of nAl and on the energy and safety of explosives are summarized in this paper. The results show that surface coating of nAl can not only improve the compatibility between nAl and energetic materials, reduce the hygroscopicity of energetic composites, mitigate the easy oxidation of nAl, and protect the preparation process, but also improve the energy performance of explosives and the burning rate of propellant, increase the reaction characteristics of energetic mixtures, and reduce the mechanical sensitivity of those mixtures. In addition, the surface coating modification of nAl can obviously reduce the agglomeration of condensed-phase combustion products, thus reducing the loss of propulsion efficiency caused by agglomeration. This study is expected to provide reference for the surface coating of nAl and its application in explosives. Full article

Atmospheric water harvesting, as an emerging water collection technology, is expected to mitigate water resource crises. Adsorption-based atmospheric water harvesting technology offers distinct advantages, including geographical independence and reduced reliance on ambient humidity levels. Herein, a thermoresponsive gel (PNIPAM/TO-CNF) integrated with lithium chloride was constructed to achieve accelerated moisture sorption and rapid desorption capabilities. In the designated PNIPAM/TO-CNF/LiCl gel, PNIPAM provided a temperature-responsive hydrophilic–hydrophobic transition network; the hydrophilicity and structural strength were enhanced by TO-CNF, the moisture absorption capacity was dramatically elevated by hygroscopic salt LiCl, and pore-forming agent polyethylene glycol created a favorable porous structure. This synergistic design endows the gel with an optimized hydrophilic network, temperature-responsive behavior, and a porous architecture conducive to water vapor transportation, thereby achieving rapid moisture absorption and desorption. Under 60% relative humidity, the gel exhibited a water vapor adsorption capacity of 144% within 1 h, reaching its maximum absorption capacity of 178% after 140 min. The gel exhibited an even more superior desorption performance: when heated to 70 °C, its moisture content rapidly decreased to 16% of its initial weight within 1 h, corresponding to the desorption of 91% of the total absorbed water. A simplified pore-forming methodology that enables the integration of temperature-responsive properties with efficient moisture transfer channels was reported in this paper, providing a viable design pathway for achieving accelerated adsorption–desorption cycles in atmospheric water harvesting. Full article

Contemporary construction faces the need to reduce its negative impact on the environment, prompting designers, investors, and contractors to seek more sustainable materials and technologies. One area of dynamic development is the use of natural fibers as an alternative to conventional, often synthetic, building components. Plant- and animal-based fibers, such as hemp, flax, jute, straw, bamboo, and sheep’s wool, are characterized by low energy consumption in production, renewability, and biodegradability. Their use is in line with the concept of a circular economy and reduces the carbon footprint of buildings. Natural fibers offer a number of beneficial physical and functional properties, including good thermal and acoustic insulation parameters, as well as hygroscopicity, which allows for the regulation of indoor humidity, improving air quality and comfort of use. In recent years, there has also been a renaissance of traditional building techniques, such as straw construction, often combined with modern engineering standards. Their potential is particularly recognized in green and energy-efficient construction. The article provides an overview of the types of natural fibers available for use in construction and analyzes their technical, environmental, and economic properties. It also draws attention to current regulations, standards, and certifications (e.g., LEED, BREEAM) that promote the popularization of these solutions. In light of the analyzed data, the role of natural fibers as a viable alternative supporting the transformation of the construction sector towards sustainable development is considered. Full article