Search Results (21,881)

Traditional enzyme-induced carbonate precipitation (EICP) technology for brick crack rehabilitation is commonly plagued by solution clogging and low repair efficiency. To overcome these technical limitations, a novel centrifugal cementation method was proposed in this study, with its core innovation lying in decoupling the EICP reaction from the masonry reinforcement process. After the complete reaction of urease with the cementation solution, a high-concentration calcium carbonate colloid was extracted via centrifugation, which was then mixed with fine sand to prepare a repair mortar for direct injection into brick cracks. The experimental results, based on a single-factor design with a fixed soybean powder concentration (180 g/L, peak urease activity), showed that the maximum flexural strength of the repaired bricks reached 2.31 MPa, recovering as much as 122.9% of that of the cracked unrepaired bricks. Furthermore, the flexural strength of the repaired bricks exhibited a significant positive correlation with the calcium carbonate content (20–100%) and curing time (3–28 days). Phase analysis indicated that the repair mortar was primarily composed of calcite and quartz. The high shear force generated by centrifugation triggered explosive nucleation of calcium carbonate, and spherical calcite particles were formed through Ostwald ripening, exhibiting a distinct characteristic of decoupling between the spherical morphology and calcite crystal phase. The centrifugal cementation method proposed in this study achieves excellent short-term repair effects for masonry structures under laboratory conditions, thus providing a novel technical approach for the crack rehabilitation of masonry structures. Full article

With the expansion of global oil and gas resource exploration and development into deep and ultra deep layers, the efficient development of deep carbonate rock fracture cave reservoirs has become the key to ensuring energy security. However, this type of reservoir commonly faces high temperatures, high salinity, and extremely strong heterogeneity, leading to increasingly severe water content spikes caused by dominant water flow channels. Although the existing traditional inorganic plugging agent has good temperature resistance, it has the defects of great brittleness and easy cracking, while the organic polymer gel is prone to degradation failure under high temperature and high salt environments. In order to solve the above problems, a new biochar-enhanced inorganic composite gel system was constructed by using biochar prepared from agricultural and forestry waste pyrolysis as a functional enhancement component. Through rheological testing, high-temperature and high-pressure mechanical experiments, long-term thermal stability evaluation, and dynamic sealing experiments of fractured rock cores, the reinforcement and toughening laws and rheological control mechanisms of biochar on inorganic matrices were systematically studied. Research has found that a biochar content of 0.5 wt% can significantly improve the micro pore structure of the matrix. By utilizing its micro aggregate filling effect and interfacial chemical bonding, the compressive strength of the solidified body can be increased to over 2 MPa, and there is no significant decline in strength after aging at 130 °C for 30 days. More importantly, the unique “adsorption slow-release” mechanism of biochar effectively stabilizes the hydration reaction kinetics at high temperatures, extending the solidification time of the system to 15 h and solving the problem of flash condensation in deep well pumping. This system exhibits excellent shear thinning characteristics and crack sealing ability, and presents a unique “yield reconstruction” toughness sealing feature. This study elucidates the multidimensional strengthening mechanism of biochar in inorganic cementitious materials, providing technical reference for stable oil and water control in deep fractured reservoirs. Full article

This study investigates the key performance-related fuel properties of emulsifier–diesel solutions and ethanol-in-diesel microemulsions. This work begins with the in situ polymerization of long alkyl chain-substituted glycidyl methacrylate (R-GMA) in diesel and the optional presence of a second methacrylate monomer. The resulting diesel-soluble oligomer functions as a nonionic emulsifier. Controlled amounts of ethanol are subsequently incorporated into the emulsifier–diesel solution to form a stable microemulsion, referred to as E-Diesel. This study examines how the structure of the emulsifier influences key fuel properties, including (i) ethanol–diesel miscibility, (ii) gross calorific value, (iii) Ramsbottom carbon residue (% of fuel), (iv) entrapped polycyclic aromatic hydrocarbons (PAHs), and (v) fuel lubricity. Both the hydrophilic–hydrophobic balance and the structure of the emulsifier side chains are found to significantly affect these properties. Compared with neat diesel, oligomeric emulsifiers enable the substantial dispersion of ethanol in diesel (up to 18 wt.%). The resulting fuel exhibits a gross calorific value exceeding the theoretical sum of diesel and ethanol at the same composition (a synergistic effect) and achieves an enhancement in lubricity up to 49.5% relative to neat diesel at a 5% emulsifier loading. Although the presence of emulsifiers leads to an increase in the carbon residue by up to 54.7% compared to neat diesel during controlled pyrolysis, it simultaneously reduces the PAH content in the exhaust. Overall, this study establishes fundamental correlations among microemulsion stability, combustion synergy, carbon residue formulation, and fuel lubricity, which are governed by the structure of the emulsifier. Full article

To meet the demand for rapid detection of methylene blue residues in aquatic products, this study constructed a composite structure modified with silver nanoparticles on the surface of a glassy carbon sheet for precise detection. This composite film used the synergistic effect of the composite structure, which significantly enhanced the current response between the composite film and MB. The CV and EIS results demonstrated that this composite structure exhibited outstanding performance, endowing the composite film with the capability for sensitive detection of methyl blue. The results showed that the composite film detected methylene blue by differential pulse voltammetry, with a limit of detection as low as 1.6 nM. In the concentration range of 10 nM to 120 nM, the current intensity presented a good linear relationship with the concentration of MB. In addition, this composite film successfully identified methylene blue in aquatic products, with a recovery rate ranging from 81% to 113%. The results indicated that the composite film could be effectively applied to the sensitive detection of methylene blue in complex samples. This study provided a reliable and easy-to-construct electrochemical sensing platform for aquatic product safety monitoring. Full article

In this study, the Monte Carlo (MC) method is employed to generate the diameter and relative positional distributions of carbon nanotubes (CNTs). Based on this, we develop a three-layer thermal model for a copper-carbon nanotube (Cu-CNT) through-silicon via (TSV). By integrating Gauss–Hermite quadrature with the Law of Large Numbers (LLN), an analytical expression for thermal conductivity is derived, enabling efficient and accurate estimation of the thermal conductivity of Cu-CNT-filled TSV. Contrary to expectations, the thermal conductivity of TSV does not increase significantly with CNT volume fraction, primarily due to the interfacial thermal resistance at Cu-CNT and CNT-CNT junctions. Through calibration against previously reported experimental data, the effective Cu-CNT interfacial thermal resistance is estimated to be on the order of 10⁻⁷ m²K/W. Comparison with previously reported effective thermal conductivity data of Cu-CNT composites shows that the model maintains an error below 2% when the CNT volume fraction is below 10%. The model is therefore most suitable for low CNT volume fractions, where the assumed spatial distribution and structural simplifications remain physically valid. Furthermore, this study investigates the influence of TSV length on thermal performance, predicts the variation in thermal conductivity of Cu-CNT composites under different volume fractions, and the extracted thermal conductivity values are further used as material inputs for device-level electro-thermal COMSOL 6.1 simulations. Full article

This work explores the effect of nitrogen ion implantation on the wettability of the cemented tungsten carbide–cobalt (WC–Co) tool surface used for wood-based panel machining. Nitrogen ions with an energy of 50 keV and a fluence of 1 × 10¹⁷ and 5 × 10¹⁷ cm⁻² were implanted into the surface layer of commercially available WC–Co indexable knives using the implanter without a mass-separated ion beam. The wettability was characterized by a contact angle instrument. The implantation of nitrogen ions into WC–Co tools caused a statistically significant and practically useful decrease in the contact angle. This obtained effect was dependent on the fluence of the implanted ions, and it changed over time. This effect may also explain the transfer from the workpiece and the surface capture of carbon atoms in the secondary structure formed during the machining of wood materials on tools with ion implantation. On the other hand, the layer of carbon on the surface of the tool formed during machining explains the reduction in friction coefficient observed in experiments and the increase in tool life during cutting. Full article

In developing countries, sustainable development strategies are increasingly shifting toward a green economy that integrates economic, social, and environmental dimensions. Despite the growing importance of green economic growth, comparative empirical studies examining its determinants in Turkey and Romania remain limited. This study investigates the dynamic relationships between environmentally sustainable growth, carbon emissions, life expectancy, renewable energy consumption, education, and technological innovation in Turkey and Romania over the period 1980–2023. Using annual time series data, the analysis applies the Augmented Dickey–Fuller and Zivot–Andrews unit root tests to examine stationarity and potential structural breaks. The empirical framework is based on the Autoregressive Distributed Lag (ARDL) bounds testing approach, which allows the estimation of both long-run equilibrium relationships and short-run dynamics. The results provide partial evidence of long-run relationships among the variables. Although the ARDL bounds test results fall within the inconclusive region, the negative and statistically significant error correction terms indicate that deviations from long-run equilibrium are corrected over time. The findings also reveal heterogeneous short-run causal interactions across the two countries, suggesting that the drivers of environmentally sustainable growth differ between Turkey and Romania. Overall, the results highlight the importance of country-specific policy frameworks, institutional structures, and energy transition pathways in promoting green economic growth. Full article

Earthquakes are rare and infrequent natural phenomena with considerable consequences for the urban environment, human life and society. Croatia is a country highly exposed to seismic risks due to its geographical location and its large stock of unreinforced masonry buildings (URM). This article proposes an assessment of their vulnerability by combining a macroseismic approach, allowing for a comprehensive analysis of a group of buildings, with detailed numerical modelling of a building in Zagreb using 3Muri 12.2 software. Three reinforcement techniques are compared in terms of their structural performance, cost, carbon footprint and compatibility with the built heritage. The study shows that each method has advantages and limitations: shotcrete is low-cost but has a high carbon impact and can be too invasive for heritage buildings; FRP offers the best structural performance but remains very expensive, while FRCM appears to be a balanced compromise, combining performance, durability and compliance with architectural conservation constraints. This article highlights the importance of adapting the approach to each situation and combining reliable assessment with appropriate reinforcement solutions. It also invites reflection on the possibility of linking seismic interventions and energy renovations to improve safety, economy, sustainability and living comfort. Full article

Forest height is a key structural parameter for characterizing forest architecture and estimating carbon storage. However, under complex terrain and heterogeneous forest conditions, Polarimetric synthetic aperture radar (PolSAR)-based forest height inversion using multi-category features still faces several challenges, including feature redundancy, insufficient characterization of the nonlinear couplings among high-dimensional features by deep learning models, and the difficulty of jointly achieving model stability and interpretability. In this paper, to address these issues, we propose a method for SHapley Additive exPlanations (SHAP) interpretability-driven PolSAR forest height inversion based on deep learning and multi-category feature fusion. Firstly, a deep neural network (DNN) is constructed, and SHAP is introduced to interpret the model decision process, enabling the identification of key feature interactions with clear physical significance and guiding the iterative model optimization in an explainability-driven manner. Furthermore, a SHAP-guided feature attention DNN is developed, in which the feature contribution scores are incorporated as prior knowledge for attention weight initialization, thereby establishing a closed-loop modeling framework from “interpretation” to “optimization”. Experiments were conducted at the site of the Huangfengqiao forest farm, Youxian County, Hunan province, China, using ALOS-2 L-band fully polarimetric SAR imagery. The experimental results demonstrated that the proposed method can significantly outperform the conventional machine learning approaches and various deep learning architectures for forest height inversion. The final model achieved a coefficient of determination (R²) score of 0.75 and a root-mean-square error (RMSE) of 1.35 m on the test dataset. These findings indicate that the combination of SHAP-driven multi-category feature fusion and deep learning can effectively enhance both the inversion accuracy and physical interpretability, providing a reliable solution for PolSAR-based forest structural parameter retrieval at the Huangfengqiao study site, with potential applicability to complex terrain conditions. Full article

The energy system is transforming in clean, low-carbon, safe, and efficient directions. As a key carrier of energy consumption, the operation optimization of the integrated energy system (IES) in industrial parks has become an important lever for facilitating energy transformation. This paper focuses on the modeling of the operation optimization of the IES, pays attention to the impact of electricity–carbon–green certificate coordination, and studies the operation optimization of the IES considering hydrogen energy utilization. Firstly, the topological structure of IES is analyzed, and a model of the integrated energy system in industrial parks covering multiple energy links, such as electricity, heat, and gas, is constructed. Hydrogen energy conversion units such as electrolyzers, fuel cells, and methane reactors are introduced. Secondly, the impact of electricity, carbon, and green certificate markets on the operation of IES is analyzed, and a green certificate-carbon trading integration mechanism is designed, along with the establishment of a corresponding market trading model. Then, with the system’s energy purchase and sale costs, electricity curtailment costs, carbon market transaction costs, green certificate transaction revenues, and equipment operation and maintenance costs as the core, an IES daily optimization scheduling model is constructed to minimize the overall cost. Finally, the feasibility of the model constructed in this paper is verified through a case study in the industrial park in the north of Dezhou, Shandong Province, and the result shows that the cost of IES is 15,013.7 yuan under the optimal operation schedule. The utilization rate of new power energy reaches 89.6%, and the 2.135 green certificates are converted into the carbon market. Meanwhile, comparative analysis across multiple scenarios and sensitivity analysis of single factors are conducted to discuss the necessity and effectiveness of the factors considered in this paper, providing a decision-making basis and inspiration for managers to carry out IES operation scheduling. Full article

In the context of the “dual carbon” goals, this study examines the spatiotemporal patterns and evolution of urban low-carbon coordinated development (LCCD). Based on the integrated Economy–Energy–Environment–Society (3E1S) framework, this study constructs a multidimensional evaluation index system for urban LCCD and applies a composite system coordination degree model to quantitatively assess and analyze the spatiotemporal evolution of LCCD across 271 prefecture-level and above cities in China from 2005 to 2020. The results indicate that (1) from a temporal perspective, the level of urban LCCD in China exhibits an overall upward trend during the study period, with relatively rapid growth from 2005 to 2015, a subsequent slowdown after 2015, and a stage-wise decline observed in 2020, reflecting a transition from rapid improvement to gradual adjustment; (2) from a spatial perspective, urban LCCD demonstrates a certain degree of spatial autocorrelation and an overall spatial structure characterized by a southwest–northeast-oriented axis, with spatial agglomeration features gradually strengthening over time; (3) from a system structure perspective, the coordinated evolution of the 3E1S subsystems shows clear differentiation, with the energy and economic subsystems following an inverted U-shaped trajectory, the environmental subsystem exhibiting a fluctuating upward trend, and the social subsystem maintaining continuous improvement, highlighting the inherent imbalance in the multidimensional process of subsystem coordination. From a multisystem coordination perspective, this study systematically identifies the spatiotemporal evolutionary characteristics and subsystem coupling relationships of urban low-carbon coordinated development, providing empirical evidence for a deeper understanding of multidimensional low-carbon coordination processes in cities. Full article

In the context of the “dual-carbon” targets and the development of green building materials, lightweight mortar has attracted considerable attention, owing to its low density and excellent thermal insulation properties. However, lightweight aggregates, such as vitrified microspheres, while effectively reducing mortar density, exhibit high porosity and weak interfacial bonding, which compromise mechanical performance. To address this issue, this study introduces sugarcane bagasse fiber (SBF) as a reinforcing material, with contents of 0%, 0.4%, 0.8%, 1.2%, and 1.6%. The effects of SBF on physical properties (consistency, density, water absorption) and mechanical properties (compressive strength, flexural strength, and tensile bond strength) were systematically evaluated. Furthermore, low-field nuclear magnetic resonance (LF-NMR) and scanning electron microscopy (SEM) were employed to analyze pore structure and interfacial transition zone (ITZ) characteristics at multiple scales. The results indicate that: (1) at low contents (0.4–0.8%), SBF was uniformly dispersed, improving matrix compactness; (2) compared with the control group, the 28-day compressive, flexural, and tensile bond strengths increased by 7.1%, 13.1%, and 25%, respectively; (3) NMR analysis revealed that the incorporation of SBF significantly increased the proportion of capillary pores, reduced total porosity, and enhanced mortar compactness, thereby improving mechanical strength; (4) fractal dimension analysis showed that contents of 0.4% and 0.8% increased structural complexity while reducing pore connectivity, leading to higher compressive strength; (5) SEM observations further demonstrated that the fibers provided bridging and anchoring effects within the ITZ, promoted the deposition of hydration products, and enhanced interfacial compactness. Full article

The objective of this scientific study is to examine whether the climate change attention of the chief executive officer promotes corporate social responsibility. To perform the extensive calculations required for this analysis, the study utilizes comprehensive panel data sourced from Carbon Disclosure Project, KLD, and financial databases. The scientific research methods used include two-stage instrumental variable estimation and difference-in-differences approaches to rigorously establish a causal relationship. The results identify a significant positive correlation between chief executive officer climate change attention and overall corporate social responsibility. Specifically, this executive focus significantly improves external and internal corporate social responsibility while reducing socially irresponsible performance; however, it does not enhance material corporate social responsibility. Furthermore, the findings indicate that this positive effect is significantly amplified when chief executive officers are in the early stages of their careers or receive high compensation, particularly equity-based compensation. Additionally, the implementation of a corporate low-carbon strategy serves as an important mediating channel for improving social performance. In conclusion, executive cognitive attention is a fundamental determinant of a firm’s strategic behaviors. It is recommended that corporate boards structure equity-based compensation to align with sustainability goals and actively support low-carbon strategies to maximize the positive impact of executive attention on sustainable development. Full article

Conventional phenolic-resin-based carbon fiber paper (CFP) typically suffers from low mechanical strength, poor toughness, insufficient pore interconnectivity, and a reliance on extreme high-temperature graphitization to attain high conductivity. This study employs a novel melamine-hexamethylenediamine (MH) thermosetting resin as the binder to fabricate MH resin-based CFP (MHCFP). Through the synergistic effects of robust interfacial bonding, triazine-ring-induced low-temperature formation of sp² carbon clusters, and nitrogen doping, the MHCFP achieves comprehensive performance superiority over the phenol-formaldehyde (PF)-based CFP (PFCFP) at moderate carbonization temperatures (500–700 °C): MHCFP exhibits superior toughness, tensile strengths of 23–45 MPa (vs. PFCFP’s 8–18 MPa), and in-plane resistivity of 24–39 mΩ·cm (vs. PFCFP’s 54–83 mΩ·cm). Furthermore, MHCFP possesses a highly open macroporous structure (porosity > 78%), ensuring excellent gas permeability and water management capability. This work presents a promising low-temperature strategy for developing high-performance CFP, showing great potential for next-generation proton exchange membrane fuel cell gas diffusion layers. Full article

This study takes the relevant literature published in the past decade as the research object, screens the literature by setting clear inclusion and exclusion criteria, and systematically reviews the thermal insulation performance, durability, and prospects for engineering applications of bio-based thermal insulation materials by means of qualitative integration and comparative analysis. With the advantages of low energy consumption, renewability, and biodegradability, bio-based thermal insulation materials have emerged as a green alternative to traditional thermal insulation materials. This paper systematically reviews the research progress of such materials, which are classified into two categories: natural biomass (e.g., straw bales and cork boards) and bio-based composites. The core thermal insulation indicators include thermal conductivity, thermal resistance, and thermal storage coefficient, and the performance is affected by factors such as component ratio, pore structure, temperature, and humidity. The thermal conductivity of some bio-based materials is comparable to that of expanded polystyrene (EPS) and mineral wool. In terms of durability, temperature–humidity cycling, corrosion, biological erosion, and mechanical action are the main causes of performance degradation, and composite modification can effectively improve their stability. Current engineering applications face challenges such as thermal insulation performance being susceptible to humidity, poor construction compatibility, high costs, and a lack of relevant standards. Future research should focus on the development of high-performance composite systems, the investigation of long-term durability mechanisms, the innovation of low-cost green preparation technologies, and the establishment of unified standards, so as to promote the large-scale application of bio-based thermal insulation materials in the construction industry and contribute to the achievement of carbon neutrality goals. Full article