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• Vegetation greening is the major driver of ET and water resource risks. • Temperature mainly indirectly affected ET and water resource risks. • Water resource risks are concentrated in the middle and upper reaches of the YRB. • Water-saving should be prioritized in ecological restoration strategies. Quantifying the impacts of climate change, vegetation greening and human activities (CVH) on evapotranspiration (ET), surface drought intensity (ET divided by precipitation, SDI), and vegetation available water (precipitation minus ET, VAW) would improve our understanding of water cycle processes. The Yellow River Basin (YRB) is a significant climate-sensitive region in China, resulting in an obvious spatiotemporal heterogeneity of ET, SDI, and VAW in response to driving variables. In this study, we analysed the spatiotemporal variation characteristics of ET, SDI, and VAW in the YRB from 1984 to 2018. We also quantified the direct and indirect contributions of the CVH to the changes in ET, SDI, and VAW, and revealed the influence mechanism of each link. Finally, water resource risks were assessed from a probabilistic perspective. The results indicated that vegetation greening was the primary driver of ET with an increase rate of 1.60 mm/a, which was also the most important influencing factor of SDI increase and VAW decrease. Leaf area index (LAI) and relative humidity (RH) jointly dominated the ET changes in 66 % of the YRB, temperature (Temp) dominated the SDI changes in nearly half of the basin, precipitation (Pre) and LAI jointly dominated the VAW changes in 66 % of the YRB. Temp indirectly influenced ET primarily through LAI, whereas LAI primarily influenced ET directly. Temp had a significant direct impact on SDI, while LAI mainly influenced SDI through RH and wind speed (WS). Temp exhibited the most substantial negative influence on VAW. LAI was identified as the primary factor contributing to water resource risks, with a probability reaching 0.8, while the probabilities associated with other factors inducing such risks were similar at the basin level, but disparities existed among different land use types. The findings of the study significantly enhanced our understanding of the role that the CVH played in hydrological processes, serving as a crucial foundation for achieving a balance between ecological restoration and socio-economic development in the YRB. [ABSTRACT FROM AUTHOR]

This study investigates how digital technology shocks can transform monetary policy. Using macroeconomic data from China from 2005 to 2022, this study empirically tests the time-varying dynamic correlation between digitalization, money supply, and output using the TVP-VAR model. The results show that the stimulating effect of loose monetary policy on output has gradually weakened in recent years. In contrast, digital technology has gradually become a new driving force for economic growth. Furthermore, this study incorporates a digital technology R&D department into the standard DSGE model and internalizes digital technology within the economic cycle to analyze the macroeconomic effects of digital technology shocks. Numerical simulations show digital technology shocks can effectively stimulate output and suppress inflation. Moreover, the central bank's welfare utility is maximized under a price-based, quantity-assisted monetary policy. Finally, this study begins with the price stickiness perspective to explain how digital technology weakens the effectiveness of monetary policy. This study enriches the literature on monetary policy regulation and provides insights for monetary policymakers to address the challenges the digital economy poses. • The stimulating effect of loose monetary policy on output has gradually weakened in recent years. • Digital technology has gradually become a new driving force for economic growth. • Under the impact of digital technology, price-based quantity-assisted monetary policy can maximize social welfare. • The digital economy weakens the effect of monetary policy by reducing price stickiness. [ABSTRACT FROM AUTHOR]

In cold regions, hydraulic concrete structures are exposed to harsh environmental conditions that greatly impact their durability and safety. The role of aggregates in influencing concrete performance is paramount. This study aims to investigate how the fractal distribution and size of aggregates affect the frost resistance of hydraulic concrete, with air void characteristics, mass loss rate, Elastic Modulus of dynamic, and strength serving as primary references. Two experiment series, fractal distribution influence and aggregate size influence of concrete frost resistance, were conducted to analyze the frost resistance of hydraulic concrete with different aggregates. Based on the fractal theory, four grading fractal distributions were utilized to fractalize aggregate gradation, aiming to investigate the influence of aggregate fractal dimension on the frost resistance of hydraulic concrete. Simultaneously, concrete specimens of fully graded aggregate and wet-screened aggregate were also constructed to simultaneous freeze-thaw cycle tests, the impact of aggregate size on concrete's frost resistance performance was also studied by analyzing the air void structure in the frost-resistant concrete specimens. Results indicate that the specimens exhibit varying frost resistance performance under different aggregate gradation fractals, ranking from strongest to weakest as follows: D=2.5, D=2.3, D=2.1, D=2.7, which is attributed to the differences of air void spacing factors. Increasing aggregate size leads to greater internal structural heterogeneity in concrete, resulting in an increase in defects and weak points. This causes microcracks to develop more rapidly in the transition zone of fully graded concrete during freeze-thaw cycles, leading to more severe damage. The findings of this study can serve as a fundamental scientific basis for the designing and constructing of hydraulic concrete structures in cold areas. • Frost resistance of hydraulic concrete declines in order of fractal dimensions: D=2.5, D=2.3, D=2.1, D=2.7. • The wet-screened concrete with smaller coarse aggregate sizes demonstrates superior frost resistance to fully graded concrete. • The varying frost resistance performance of concrete specimens is attributed to differences in the air void structures. [ABSTRACT FROM AUTHOR]

• Insulation materials coupling the immersion and freeze–thaw cycles were performed. • Mass water content and thermal conductivity was increased significantly. • A prediction model for the thermal conductivity of thermal insulation materials was presented. • The sensibility of various impact factors was quantitatively evaluated by machine learning. The processes of groundwater flow and freeze–thaw cycles negatively affect the thermal performances of insulation materials in cold-region tunnels and notably reduce their long-term service performances. Therefore, this study investigated the water absorption and microscopic characteristics of three insulation materials (namely, polyphenolic materials, polyurethane, and polystyrene) under water immersion and freeze–thaw cycles based on indoor tests, and a model was developed to calculate the thermal conductivity considering environmental factors. Four machine learning methods were also used to verify its accuracy in thermal conductivity prediction, and model evaluation and multi-factor analysis were performed. The results showed that the mass water contents of the three materials were positively correlated with the head pressure and number of freeze–thaw cycles, and the maximum values for the polyphenolic insulation material, polyurethane, and polystyrene reached 1585.37 %, 373.42 %, and 286.86 %, respectively. Compared with the values in the initial dry state, the thermal conductivities of the three materials with the maximum water content increased 11.52, 3.00, and 0.67 times in the thawed state, respectively, while in the frozen state, they increased 26.59, 6.25, and 2.45 times, respectively. The thermal conductivities of the insulation materials had good correlations with the water contents, and the introduction of the environmental factor could improve the accuracy of the calculation model. The backpropagation neural network had the highest accuracy for predicting the thermal conductivity, and the order of importance of the factors was as follows: frozen and thawed states > mass water content > head pressure > material type > freeze–thaw cycles. The results can provide guidance for the selection and design of the insulation materials for tunnels in cold regions. [ABSTRACT FROM AUTHOR]

This paper presented the role of supplementary cementitious materials (SCMs), including fly ash (FA), granulated blast-furnace slag (GBFS), and silica fume (SF) in long-term resistance to external sulfate attack (ESA) of cement mortar at atmospheric temperature. The cement mortars were immersed in 5% sodium sulfate solution at a temperature of 20 °C for 36 months. The results showed that the amount of deterioration products and pore characteristics were the two critical factors affecting sulfate resistance. The pore characteristics played more integral roles in influencing the long-term sulfate resistance than the amount of deterioration products. FA maintained excellent sulfate resistance after exposure to ESA for 36 months. SF exhibited higher sulfate resistance than FA because it primarily supported total porosity and percentage of harmless pore, rather than the portlandite removal by the pozzolanic reaction. On the contrary, the addition of GBFS accelerated the deterioration process and exhibited the worst sulfate resistance because the total porosity and percentage of harmless pore occurred massive changes. [ABSTRACT FROM AUTHOR]

• The hydration and microstructure of ternary LHPC blends incorporated a large amount of FA and PS were revealed. • The synergistic impacts between FA and PS in LHPC ternary blends decreased the drying shrinkage, cumulative heat, and refined pore structure. • The single addition of PS had the lowest strength-normalized cost. • LHPC-FA-PS ternary blends pronounced advantages in the strength-normalized energy consumption and the carbon footprint. This paper presents the benefits of utilizing phosphorus slag (PS) to replace fly ash (FA) in low-heat Portland cement (LHPC) blends. After the first three days, PS exhibits worse mechanical properties and lower hydration heat compared to FA, presumably owing to its retarding effect. Meanwhile, the mechanical properties of PS are approached that of FA at 180 days. Based on the Krstulovic-Dabic (K-D) model, the Q max values of LHPC, L75F25 (where the letters stand for the material and the numerals indicate the composition percentage), L65F35, L75P25, L65P35, and L50F25P25 are: 370.4 J/g, 312.5 J/g, 323.6 J/g, 333.3 J/g, 322.6 J/g, and 238.1 J/g, respectively. The effects of pozzolanic reaction and pore structure refinement of PS are more pronounced than that of FA, resulting in the Q max of PS being relatively higher compared to FA. The number of gel capillaries (d < 10 nm) in L75P25 is 12% higher compared to L75F25 at 90 days. The pozzolanic reaction in FA is mainly occurred within 3 days to 28 days. However, in PS the corresponding period is from 28 days to 90 days. Furthermore, the synergistic impact between FA and PS in LHPC ternary blends is further decreased the drying shrinkage and cumulative heat, increases the H/LHPC content, and refines the pore structure. L75P25 has the lowest strength-normalized cost, which is 0.069 $/t/MPa ∼ 0.100 $/t/MPa less compared to L75F25. LHPC-FA-PS ternary blends has pronounced advantages on the strength-normalized energy consumption and carbon footprint. The strength-normalized carbon footprint and energy consumption of L50F25P25 are 1.89 kg/t/MPa and 5.57 MJ/t/MPa lower compared to L75F25, respectively. [ABSTRACT FROM AUTHOR]

• The hydration and microstructure of ternary HFC blends incorporated a large amount of FA and LP were revealed. • The synergistic effects between FA and LP in ternary HFC blends exhibit improving flexural strengths, decreasing drying shrinkage and cumulative heat. • The adverse effects between FA and LP in ternary HFC blends mainly exhibits decreasing compressive strengths and increasing total porosity percentages. • The synergistic effects between FA and LP in ternary HFC blends are mainly occurred at a later age. This paper studied the mechanical properties, hydration process, and microstructure of ternary high-ferrite Portland cement (HFC) blends with replacement at levels up to 50 % with limestone powder (LP) and fly ash (FA). Two mechanisms, synergy and negative effects between LP and FA are observed in ternary HFC-LP-FA blends. The synergistic effects between LP and FA in ternary HFC blends mainly exhibit improving flexural strengths, improving compressive strengths before 28 days, decreasing drying shrinkage and cumulative heat, accelerating the crystal nucleation and growth process (NG), stabilizing the ettringite (AFt) phase, prolonging polymerization of alumino-silicate chains, and refining the pore size distribution, etc. However, the synergistic effect between LP and FA in ternary HFC blends cannot compensate for the dilution effect caused by a large amount of LP and FA replacement. The adverse effects between LP and FA in ternary HFC blends are emerged and mainly exhibited decreasing in compressive strengths after 28 days and increasing total porosity percentages. LP plays a predominant role at an early age (before 28 days) in HFC blends and increases the cumulative heat; Specifically the cumulative heat of LP25 (25 indicates percentage replacement of HFC) before 10 h is 2.2 J/g higher compared to HFC. In addition, a rapid increase of bound water is emerged from 3 days to 28 days, for instance the bound water content in LP25 increases by 55.9 % from 3 days to 28 days. It is attributed to the nucleation effect of LP providing more nucleation sites and accelerating NG process. LP in HFC blends leads to the formation of monocarbonate and AFt phase trends to stabilization. FA plays a predominant role at the later hydration age (from 28 days to 90 days) in HFC blends attributing its pozzolanic reaction. Furthermore, the synergistic effects between FA and LP in ternary HFC blends are mainly occurred at a later age. [ABSTRACT FROM AUTHOR]

• Construct a data-driven two-stage distributionally robust CIES scheduling model. • Propose data-driven scenario analysis via WGAN-GP to handle renewable uncertainty. • Analyze the ambiguity of human thermal comfort and thermal inertia of buildings. • Simulation tests were carried out on an actual CIES in North China. A community integrated energy system (CIES) is an important carrier of the energy internet and smart city in geographical and functional terms. Its emergence provides a new solution to the problems of energy utilization and environmental pollution. To coordinate the integrated demand response and uncertainty of renewable energy generation (RGs), a data-driven two-stage distributionally robust optimization (DRO) model is constructed. A comprehensive norm consisting of the 1-norm and ∞-norm is used as the uncertainty probability distribution information set, thereby avoiding complex probability density information. To address multiple uncertainties of RGs, a generative adversarial network based on the Wasserstein distance with gradient penalty is proposed to generate RG scenarios, which has wide applicability. To further tap the potential of the demand response, we take into account the ambiguity of human thermal comfort and the thermal inertia of buildings. Thus, an integrated demand response mechanism is developed that effectively promotes the consumption of renewable energy. The proposed method is simulated in an actual CIES in North China. In comparison with traditional stochastic programming and robust optimization, it is verified that the proposed DRO model properly balances the relationship between economical operation and robustness while exhibiting stronger adaptability. Furthermore, our approach outperforms other commonly used DRO methods with better operational economy, lower renewable power curtailment rate, and higher computational efficiency. [ABSTRACT FROM AUTHOR]

High-ferrite Portland cement (HFPC) has the advantages of excellent sulfate resistance, higher abrasion resistance, lower energy consumption, and lower CO 2 emission, and is expected to be widely utilized in erosion environmental engineering. This paper presents evolution and kinetics of hydration process, quantity of unhydrated clinker and portlandite (CH), C–S–H structure, pore structure, and mechanical properties of HFPC in the presence of fly ash (FA) and phosphorus slag (PS). PS exhibits lower mechanical properties and hydration heat in comparison with FA at early age owing to its retarding effect. The Q max order is: HFPC > PS > FA, where HFPC, PS25, and FA25 (25 indicates percentage replacement of HFPC, the same below) correspond to 345 J/g, 322 J/g, and 313 J/g, respectively, according to the Krstulovic-Dabic (K-D) model. The FA and PS retard the crystal nucleation and growth (NG) and phase boundary reaction (I), and I process of FA takes longer than PS. PS hinders the formation of CH and C–S–H at early age, and plenty of CH and high polymerization C–S–H are formed at a later time. The effects of FA on the enhancement of Al content of C–S–H and mean chain length (MCL), as well as the pozzolanic reaction are more significant than that of PS. FA and PS have a comparable total porosity at 90 days. FA has an excellent ability to refine the pore structure distribution, which reduces the prevalence of large pores (50–10,000 nm) by 17.92% and increases the proportion of small pores (2.5–20 nm) by 8.87% than PS, at 90 days. The quantity of C–S–H and pore size distribution affect the mechanical properties more than the CH content. The unhydrated C 2 S in HFPC, FA25, and PS25 are about 14.3%, 9.1%, and 22.1% at 90 days. [ABSTRACT FROM AUTHOR]

• The distribution network with ineffective neutral grounding can't realize the complete extinction of grounding fault arc. A new voltage arc suppression method based on active inverter is proposed. • An active arc suppression method based on proportional delay control can effectively suppress the grounding arc. • Compared with PI control cannot achieve zero steady-state error, the arc suppression control method proposed in this paper has high control accuracy and fast response. • The test results show that the corresponding device can quickly extinguish the grounding arc. Flexible arc suppression technology can control zero-sequence voltage flexibly and realize arc suppression completely by injecting current to the neutral point of distribution network. However, in the existing control method, PI control cannot achieve zero steady-state error, and injecting current control needs to accurately measure the phase-to-ground parameters, so it is difficult to apply it in practice. For improvement, a new control method of the flexible arc suppression device is developed by using proportional controller and lagging network controller in this paper. The double closed-loop control method and the parameters of the controller are designed to improve the injecting current control performance. The zero-sequence voltage is set as the control target of the control system to realize arc suppression completely without measuring the phase-to-ground parameters. The effectiveness of the proposed control technology is verified by PSIM simulation and practical experiments. The simulation and experimental results show that the proportional series lagging control has better response speed and stability than the existing control method. [ABSTRACT FROM AUTHOR]

Highlights: [•] 9 treatments were tested to identify the best for ‘Laiyang’ pear during cold storage. [•] 0.5μL/L 1-MCP plus micro-perforated film showed the best effects on fruit qualities. [•] 0.5 and 1.0μL/L 1-MCP did not enhance the susceptibility to CO2 injury of ‘Laiyang’ pear. [•] 0.5μL/L 1-MCP plus micro-perforated film maintained flesh color by inhibiting its senescence. [ABSTRACT FROM AUTHOR]

• A single-master multi-slave hierarchical MCIES optimization framework is proposed. • Data-driven scenario analysis via WGAN-GP is used to handle renewable uncertainty. • A DHN model is integrated into MCIES scheduling considering users' thermal comfort. • A metaheuristic-based distributed solution is designed for privacy protection. An operating entity utilizing community-integrated energy systems with a large number of small-scale distributed energy sources can easily trade with existing distribution markets. To solve the energy management and pricing problem of multi-community integrated energy systems (MCIESs) with multi-energy interaction, this study investigated a hierarchical stochastic optimal scheduling method for uncertain environments. To handle multiple uncertainties, a Wasserstein generative adversarial network with a gradient penalty was used to generate renewable scenarios, and the Kmeans++ clustering algorithm was employed to generate typical scenarios. A Stackelberg-based hierarchical stochastic schedule with an integrated demand response was constructed, where the MCIES operator acted as the leader pursuing the maximum net profit by setting energy prices, while the building users were followers who adjusted their energy consumption plans to minimize their total costs. Finally, a distributed iterative solution method based on a metaheuristic was designed. The effectiveness of the proposed method was verified using practical examples. [ABSTRACT FROM AUTHOR]

• The failure cause of the collector line protection is analyzed. • The operation states of the collector line is depicted by three current components. • The state partition is realized by distance in multi-dimensional fault space. • The proposed method improve the adaptability of relay for variable operation states. To solve the problem of incorrect collector line protection in large-scale wind farms, we propose a protection method based on fuzzy c-means (FCM) clustering analysis. The intrinsic relationship between the fault current and the voltage sag of a doubly-fed induction generator (DFIG) was analysed under fault conditions. According to the component characteristics contained in the DFIG fault current, the DC, AC power frequency, and rotation frequency under different operation conditions were extracted to form the historical data sample set. The historical feature samples were divided into either the non-fault or fault category by the FCM algorithm in the multi-dimensional fault space, thereby obtaining the clustering centres. The distance similarity criterion was used to determine the attributes of the real-time feature sample to evaluate its protection. A centralized large-scale wind farm model was established in DIgSILENT to simulate various fault and operation conditions of the collector line. The simulation results showed that the proposed protection method could trip the fault collector line accurately by considering DFIG feeding current under different fault conditions. The proposed protection method improved the relay adaptability under variable wind farm operation conditions. [ABSTRACT FROM AUTHOR]

• Properties of four-graded RCC containing large broken stones were assessed. • Correlations among different mechanical properties of RCC were established. • Positive and negative effects of large broken stones on properties of RCC were analyzed. • Freezing-thawing damage model of RCC was established based on fractal theory. The effect of large broken stone content with maximum particle size of 120 mm on the four-graded roller compacted concrete (RCC) is investigated by mechanical properties and freeze-thaw cycles tests. Using fractal geometry, the quantitative relationships of large broken stone content, mechanical behavior, and damage degree of concrete are established, which reveal the influence of large broken stone content on the mechanical properties and frost resistance of RCC. The results of fitting analyses indicate that the compressive strength and the age of RCC are significantly correlated. In addition, the correlations of different mechanical properties of RCC are established. After 150 freeze-thaw cycles, the cross-cutting cracks appear in four-graded RCC, which lead to the failure of samples, while the wet-screened RCC can reach anti-freezing level of F300. The total surface areas of four-graded RCC and wet-screened RCC with different large broken stone contents are calculated by fractal theory, which reveal the positive and negative effects of large broken stone content on the properties of RCC. Based on fractal dimension, the freezing-thawing damage model of RCC was established, which describes the correlation between the damage degree and the total surface area of four-graded RCC. [ABSTRACT FROM AUTHOR]