Search Results (317)

At present, phosphogypsum, as an industrial by-product, is a solid waste in phosphoric acid production, and its accumulation has caused serious environmental pollution. Furthermore, due to the insufficient insulation properties of traditional wall materials, the issue of a rising proportion of building energy consumption in total social energy consumption has become increasingly pressing. The study investigated vitrified beads as a light aggregate and phosphogypsum, mineral powder, and quicklime as an inorganic composite cementitious system to prepare the phosphogypsum-based lightweight thermal insulation material. The effect mechanism of the initial material ratio on the mechanical properties and micro-morphology of insulation materials was studied by macroscale mechanical property testing, X-ray diffraction, and scanning electron microscopy. Meanwhile, in order to meet the performance indexes specified in relevant standards, insulation materials were modified by adding sulfate aluminate cement, basalt fibers, and a waterproof agent to improve the strength, toughness, and water resistance. Based on the single-factor experimental design, the optimal dosage of various admixtures was obtained. The results indicated that the optimal properties of the sample were achieved when the binder–bead ratio was 1:4, the water–binder ratio was 1.6, the dosage of hydroxypropyl methylcellulose was 0.1%, and the solid content of waterborne acrylic emulsion was 24%. The optimal dosages of cement and fibers were 8% and 0.9%, respectively. The cement hydration products and gypsum crystals lapped through each other, filling the pores in the matrix and increasing the strength of the sample. In addition, the fibers could form a disordered network structure inside the matrix, disperse external force, weaken the stress concentration at the tip of internal cracks, and significantly improve the toughness of the modified sample. By incorporating 2.0% paraffin emulsion in the mortar and spraying 5 dilutions of sodium methyl silicate on the external surface, dense protective layers were formed both inside and outside the modified sample. The water absorption rate reduced from 30.27% to 23.30%, and the water resistance was increased to satisfy the specified requirement for the insulation material. Full article

Sustainable materials engineering necessitates the valorization of industrial by-products, such as coal fly ash, into functional, high-performance materials. This research addresses a core challenge in materials synthesis: establishing a deterministic technology for controlled porous structure formation to optimize the thermophysical properties of lightweight thermal insulation composites. The primary objective was to investigate the structural evolution kinetics during the high-intensity thermal processing of fly ash-based precursors to facilitate precise property regulation. We developed a novel, integrated process, underpinned by mathematical modeling of simultaneous bloating and non-equilibrium heat transfer, to evaluate key operational parameters within a vortex-layer reactor (VLR). This framework enables the a priori prediction of structural outcomes. The synthesized composite granules were subjected to comprehensive characterization, quantifying apparent density, total porosity, static compressive strength, and effective thermal conductivity. The developed models and VLR technology successfully identified critical thermal exposure windows and heat flux intensities of the heating medium required for the reproducible regulation of the composite’s porous architecture. This precise structure process control yielded materials exhibiting an optimal balance between low density (<400 kg/m³) and adequate mechanical integrity (>1.0 MPa). This work validates a scalable, energy-efficient production technology for fly ash-derived porous media. The established capability for predictive control over microstructural development provides a robust engineering solution for producing porous materials, significantly contributing to waste reduction and sustainable building practices. Full article

Young’s modulus (E), one of the many material properties, changes in response to thermal actions. The magnitude of these changes also depends on the material used. This is particularly important when the materials used are components of lightweight radiant heating systems (LRHSs) without screeds. Adhesives or adhesive composites take over the role of the screed in LRHSs. The adhesives, which directly connect the thermal insulation layer and the floor, are responsible for the proper functioning of the heated floor. Therefore, changes in their Young’s modulus cause a loss of layer integrity and ultimately delamination of the floor. Thus, research was conducted on the variation of the Young’s modulus of deformable cement adhesive mortars, specifically types C2S1 and C2S2, used in LRHSs under thermal actions. The deformation values of adhesive mortar samples were measured in a thermal chamber, subjected to compressive strength tests, at temperatures from 30 °C to 50 °C. Deformation measurements of heated samples were performed using the extensometer technique. The measurement results were subjected to mathematical analysis using polynomial regression based on the least squares method and the “Madrid parabola” formulas. After analysis, it was assumed that the Young’s modulus E for the deformable C2S1 cement adhesive, depending on the thermal action taken in the study, falls within the range of 4600 MPa to 5800 MPa when the temperature is varied from 30 °C to 50 °C. Simultaneously, the Young’s modulus E remains constant over these temperatures, at 2300 MPa for the C2S2 adhesive. Knowledge of the Young’s modulus and other strength parameters of adhesive mortars connecting layers of lightweight heated floors or other partitions, subjected to temperature can directly impact their durability. This data can be used to analyse the performance of LRHSs and numerical calculation techniques for various building partitions, such as stairs, balconies, and terraces. Full article

This study integrates dynamic energy simulation with lifecycle assessment (LCA) to evaluate the energy and carbon performance of advanced glazing systems suitable for hot–arid climates. Using Design Builder software coupled with OpenLCA, six glazing configurations were analyzed under identical building and climatic conditions. The configurations included a conventional single 3 mm float glass pane (C0) as the reference case, a single 3 mm polycarbonate sheet (C1) representing common local construction practice, and four advanced multi-layer systems (C2–C5) incorporating air, argon, and nanogel insulation layers. The inclusion of C0 enabled direct comparison between typical glass construction and emerging polycarbonate-based systems, thereby enhancing the contextual relevance of the analysis. Results demonstrated that thermal and optical properties of glazing systems strongly influence both operational and embodied carbon outcomes. Relative to the conventional glass reference (C0), the nanogel–argon composite (C5) achieved a 32.4% reduction in annual cooling energy and a 28.9% decrease in total lifecycle carbon emissions, with a carbon payback period of approximately 1.1 years. The operational phase dominated total emissions (>97%), confirming that improvements in glazing thermal performance yield substantial long-term benefits even when embodied impacts are considered. While argon filling provided marginal benefit over air cavities, the nanogel insulation contributed the largest performance enhancement. However, the relatively low visible light transmittance (VLT = 0.27) of the C5 system suggests a potential daylight–comfort trade-off that warrants further investigation. The study demonstrates the importance of integrating energy simulation with lifecycle assessment to identify glazing systems that balance energy efficiency, embodied carbon, and indoor environmental quality in hot–arid regions. Full article

Interconnect cables serve as critical components in electronic systems responsible for energy and signal transmission. Their electromagnetic compatibility directly impacts the reliable operation of the system. As internal cable layouts become increasingly complex and compact, crosstalk issues between cables have become more pronounced. In this paper, we investigate the crosstalk characteristics of complex assembled cables, proposing a transmission line coupling calculation method that accounts for the influence of cable insulation layers. We specifically address the challenges of computationally complex coupling analysis and insufficiently in-depth crosstalk characteristic analysis in real-world interconnect cable systems. First, we investigate crosstalk calculation methods for assembled interconnect cables. We analyze and extract typical branch, parallel, and vertical structural features present in assembled cables, establishing an electromagnetic coupling model for complex assembled interconnect cables. Based on multi-conductor transmission line theory and incorporating the weak coupling assumption, the direct coupling from interference sources and their reflected waves to sensitive ports, along with the four types of interference propagation paths corresponding to reflected coupling, are decomposed and identified. Building upon this, a transmission line equation accounting for insulation layer effects is proposed. Finally, the crosstalk values calculated using the proposed method are compared with experimentally measured values and those obtained from CST simulations. The comparison results indicate that under ideal transmission line conditions, the crosstalk values obtained from the three methods show minimal deviation, validating the proposed algorithm. Full article

As a critical element within the prefabricated structural system, the prefabricated shear wall connected by sleeve grouting is renowned for its superior mechanical performance and high construction efficiency. It is widely applied in mid- and high-rise buildings. However, under fire conditions, not only do the material properties degrade, but the structural connections may also fail, significantly compromising the structural stability and safety. Therefore, this study delves into the fire resistance performance of such prefabricated shear walls. The research primarily focuses on analyzing fire resistance characteristics, including deformation patterns, lateral and axial deformations, fire resistance limits, and other performance metrics, for both prefabricated and cast-in-place shear walls subjected to three hours of single-sided fire exposure. Additionally, a parametric analysis is performed. The results reveal that, after three hours of single-sided fire exposure, the temperature distribution patterns at the mid-width and mid-height sections of the prefabricated shear wall generally resemble those of the cast-in-place wall, displaying arch-shaped and strip-shaped distributions, respectively. However, due to the presence of sleeves, higher temperatures are observed near the sleeve areas in the prefabricated wall, along with a more extensive high-temperature zone. Throughout the three-hour fire exposure, both types of shear walls demonstrated satisfactory structural stability and thermal insulation performance, meeting the requirements for a first-level fire resistance rating (3 h). Nevertheless, greater axial and lateral deformations were noted in the prefabricated shear wall. Key factors influencing the fire resistance performance of the sleeve-connected prefabricated shear wall include the axial compression ratio, longitudinal reinforcement diameter, protective layer thickness, and height-to-thickness ratio. Specifically, axial deformation is found to be directly proportional to the axial compression ratio and height-to-thickness ratio, while inversely proportional to the longitudinal reinforcement diameter and protective layer thickness. Lateral deformation is directly proportional to the axial compression ratio and longitudinal reinforcement diameter, and exhibits a trend of initially increasing and then decreasing with an increase in protective layer thickness, and initially decreasing and then increasing with an increase in the height-to-thickness ratio. Full article

To accurately simulate the progression of pipeline corrosion, this paper proposes a three-dimensional corrosion modeling method for curved random surfaces based on spatial frequency composition. It applies this method to the inner surface of layered pipelines to emulate both the morphological characteristics and the evolution of internal corrosion. Combined with ultrasonic guided wave technology, the approach enables quantitative assessment of internal corrosion in layered pipelines. First, trigonometric series expansion and nonlinear polynomial superposition are used to characterize the roughness and curvature of the corroded surface, respectively, establishing a mathematical model capable of accurately representing complex corrosion morphologies. Next, a COMSOL–ABAQUS co-modeling approach is employed to build a finite element model of a three-layer composite pipeline consisting of a steel pipe, an insulating layer, and an anti-corrosion layer, with curved random-surface corrosion on the inner surface of the steel pipe. Finally, a wavelet packet decomposition algorithm is applied to extract features from the guided wave echo signals, creating a damage index matrix to correlate the corrosion area with the damage index quantitatively. The results show that the damage index increases steadily with the corrosion area, confirming the effectiveness of the proposed method. This study provides an alternative technical approach for high-fidelity modeling and precise assessment of pipeline corrosion detection. Full article

Within the scope of this article is the presentation of a modelling and measurement approach for the effects of roof greenings and the application of the approach to evaluate the influence of roof greenings upon the thermal conditions inside a typical residential building. It is shown that overheating in summer can be reduced, and thermal comfort for inhabitants can be increased. The cooling is caused by the transpiration of plants and by the evaporation of water from the substrate. Other relevant physical effects are the shading of plants and the increase in the heat capacity of the building. In state-of-the-art buildings, a layer with a high insulating effect is incorporated into the envelope. This leads to the effect that a huge fraction of the cooling power is taken from the outside of the building and only a smaller part is taken from the inside. In order to mitigate this decoupling, a hydraulic connection between the greening and the interior of the building is introduced. To evaluate the effect of the inside cooling, the difference in the number of yearly hours with overheating in residential buildings is estimated. In addition, the reduction in energy demand for the climatisation of a typical residential building is calculated. The used methods are as follows: (1) Performance of laboratory and free field measurements. (2) Simulation of a typical residential building, using a validated approach. In summary, it can be said that green roofs, in particular with hydraulic connections, can significantly increase the interior thermal comfort and potentially reduce the energy required for air conditioning. Full article

This study investigates the feasibility of using scrap aerogel (SAG) generated during silica aerogel production as a partial substitute for sand in 3D concrete printing. Through comprehensive experiments and finite element analysis, the printability, thermal insulation properties, and mechanical characteristics (compressive strength and flexural strength) of 3D-printed scrap-aerogel-incorporated concrete (3DP-SAIC) were evaluated at different SAG replacement ratios. The results indicate that the thermal conductivity of the concrete decreases with increasing SAG content. When 30% of the sand is replaced by aerogel, the thermal conductivity perpendicular to the printed layer direction is reduced by 40.90%. The thermal properties of SAIC closely resemble those of aerogel concrete (AIC) while significantly reducing manufacturing costs. Compared to existing 3D-printed aerogel concrete, this study achieves a 73.1% cost reduction. Compared to standard cast specimens (SC-SAIC), 3DP-SAIC exhibits pronounced anisotropic thermal behavior. The study also evaluated the reinforcement effects of four basalt fibers (BF) with different aspect ratios on the mechanical properties of 3DP-SAIC. Although BF provides limited enhancement to compressive strength, it significantly boosts flexural strength. Specifically, BF with a length of 12 mm and a diameter of 17 μm increases flexural strength by 26.97%. These findings highlight the application potential of recycled aerogel in 3D-printed concrete, offering a sustainable thermal insulation solution with suitable mechanical properties for green building technologies. Full article

The linear stability of convection in a vertical two-layer porous structure representing a building external wall is studied. The wall is confined by two open vertical boundaries kept at different but uniform temperatures and is composed of two homogeneous porous layers, characterized by different values of permeability and thermal conductivity. The aim of this paper is investigating whether the wall can undergo the transition to thermal instability, namely, the onset of a multicellular convective pattern. The basic stationary state, given by the fully developed buoyant flow in the vertical direction, is perturbed by means of small-amplitude disturbances, and the resulting eigenvalue problem for neutrally stable modes is studied numerically. The solution of the perturbed governing equations shows that, for suitable values of the governing parameters, thermal instability can arise. The results highlight that the ratio of the permeabilities of the two layers as well as the ratio of their thermal conductivities, together with the aspect ratio between their thicknesses, are key parameters for the possible onset of instability. The temperature difference between the two open boundaries that can trigger instability is determined with reference to practical cases, namely, insulated walls that fulfill the Italian requirements in terms of overall thermal transmittance. 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 study numerically investigates and designs, through electromagnetic and ray-tracing simulations, two types of double-sided metasurface thermal insulation glazing to maintain visible light (VIS) transmittance while effectively suppressing near-infrared (NIR) transmission, with a partial reduction in deep-blue (DB) transmission, thus reducing air-conditioning load and lighting energy consumption and contributing to overall building energy efficiency. Both designs were optimized and analyzed entirely through simulations, using structural parameter sweeps and AM 1.5 solar spectrum weighting. Design I is composed of two all-dielectric metasurfaces, aiming to maximize VIS transmittance while partially suppressing DB and reducing NIR transmission. Design II integrates a metallic layer with dielectric structures on the front side and employs an all-dielectric metasurface on the back side to enhance NIR blocking and maintain low transmittance under oblique incidence. Simulation results show that Design II outperforms Design I in NIR suppression, exhibiting lower and more stable transmittance across incident angles, while Design I achieves higher VIS transmittance. These findings present a promising pathway for developing high-performance, lightweight glazing for sustainable buildings, improving energy efficiency by balancing solar heat control and daylight utilization. Full article

This study presents a theoretical analysis of the effectiveness of the use of variatropic concretes in multi-layer panel structures of buildings in terms of heat transfer. Theoretical analysis was performed with the aid of the modern numerical modeling software package ELCUT 6.6 and the computer algebra system Maple, which helped improve the reliability of the calculations. The results of this study of the thermophysical parameters of multi-layer panels using variatropic concrete showed that an increase in the degree of variatropy contributes to a rise in the temperature on the inner surface of the panel from 17.94 °C (traditional panel) to 18.87 °C (the most variatropic panel, Scheme 4), which improves indoor comfort conditions and reduces the risk of condensation. Additionally, it is possible to reduce the thickness of the insulation layer without compromising thermal efficiency. The high thermal inertia (D > 7) of variatropic panels ensures the accumulation and retention of heat, which has a positive effect on energy consumption during the heating season. The moisture regime of the studied structures meets regulatory criteria for preventing moisture accumulation, thereby increasing panel durability and eliminating conditions for mold formation or structural degradation. The air permeability performance of the panels also complies with the standards, while the dense outer concrete layers provide additional protection against air infiltration, stabilizing both thermal and moisture balance. The calculated thermal resistance of variatropic panels (Schemes 3 and 4) exceeded the standard requirement (3.20 m²·°C/W) by 1.2 and 1.74 times, respectively. Thus, it was established that the application of the variatropic principle in panel design ensures a more rational distribution of temperature fields, which results in reduced heat losses and improved thermal stability of exterior enclosures. This approach develops new design solutions focused on improving the energy efficiency of buildings and reducing material costs, which is consistent with current trends in Functionally Graded Design (FGD). Full article

High energy consumption in Chinese rural residential buildings, caused by rudimentary construction methods and the poor thermal performance of building envelopes, poses a significant challenge to national sustainability and “dual carbon” goals. To address this, this study proposes a comprehensive modeling and analysis framework integrating an improved Bio-inspired Black-winged Kite Optimization Algorithm (IBKA) with Support Vector Regression (SVR). Firstly, to address the limitations of the original B-inspired BKA, such as premature convergence and low efficiency, the proposed IBKA incorporates diversification strategies, global information exchange, stochastic behavior selection, and an NGO-based random operator to enhance exploration and convergence. The improved algorithm is benchmarked against BKA and six other optimization methods. An orthogonal experimental design was employed to generate a dataset by systematically sampling combinations of influencing factors. Subsequently, the IBKA-SVR model was developed for energy consumption prediction and analysis. The model’s predictive accuracy and stability were validated by benchmarking it against six competing models, including GA-SVR, PSO-SVR, and the baseline SVR and so forth. Finally, to elucidate the model’s internal decision-making mechanism, the SHAP (SHapley Additive exPlanations) interpretability framework was employed to quantify the independent and interactive effects of each influencing factor on energy consumption. The results indicate that: (1) The IBKA demonstrates superior convergence accuracy and global search performance compared with BKA and other algorithms. (2) The proposed IBKA-SVR model exhibits exceptional predictive accuracy. Relative to the baseline SVR, the model reduces key error metrics by 37–40% and improves the R² to 0.9792. Furthermore, in a comparative analysis against models tuned by other metaheuristic algorithms such as GA and PSO, the IBKA-SVR consistently maintained optimal performance. (3) The SHAP analysis reveals a clear hierarchy in the impact of the design features. The Insulation Thickness in Outer Wall and Insulation Thickness in Roof Covering are the dominant factors, followed by the Window-wall Ratios of various orientations and the Sun space Depth. Key features predominantly exhibit a negative impact, and a significant non-linear relationship exists between the dominant factors (e.g., insulation layers) and the predicted values. (4) Interaction analysis reveals a distinct hierarchy of interaction strengths among the building design variables. Strong synergistic effects are observed among the Sun space Depth, Insulation Thickness in Roof Covering, and the Window-wall Ratios in the East, West, and North. In contrast, the interaction effects between the Window-wall Ratio in the South and other variables are generally weak, indicating that its influence is approximately independent and linear. Therefore, the proposed bio-inspired framework, integrating the improved IBKA with SVR, effectively predicts and analyzes residential building energy consumption, thereby providing a robust decision-support tool for the data-driven optimization of building design and retrofitting strategies to advance energy efficiency and sustainability in rural housing. Full article

Noise has detrimental effects on mental and physical health and quality of life, especially for those living in apartment buildings. Therefore, sound insulation materials are pivotal for reducing unwanted noise as well as enhancing acoustic comfort. This study offers a hybrid approach for analyzing 3D woven textile sound insulation material effectiveness, especially in residential buildings, by simulating airborne sound insulation and testing manufactured slab samples with 3D woven textile mortars in a laboratory using a tapping machine. At the same time, the JCA model and the transfer matrix method are employed to calibrate sound absorption coefficients (SAC) and simulate its airborne sound insulation effect in buildings in Seoul, South Korea. Results indicate that the maximum mean sound pressure level (SPL) of the 3D woven textile was reduced up to 9 dB in the octave band frequencies. The thickness improvement of 3D woven textiles enhances the mid- and high-frequency sound absorption effect, most pronounced in 3D woven textiles made of double-layer (DSRM) material, which demonstrated an air sound insulation efficiency around 28.5% greater than that of traditional materials. The maximum drop in impact sound pressure level (SPL) at 2 kHz is 13 dB. The study also proposes a strategy to optimize sound insulation performance, which is used as an effective solution for noise control in buildings. These findings lay the groundwork for research on the application of 3D woven textiles for sound insulation in residential buildings and offer prospects for sustainable textile composites in architectural building applications. Full article