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The adsorption behavior and dispersing capability of hyperbranched phosphated polycarboxylate superplasticizers (PCEs) containing phosphate monoester and phosphate diester were investigated. The hyperbranched structures were constructed using a special monomer dimethylaminoethyl methacrylate (DMAMEA) to create the branches during the polymerization. Meanwhile, the polymer architectures were tailored by varying the content of phosphate monoester and phosphate diester in the backbone via free radical solution polymerization. In contrast to comb-like PCE, hyperbranched PCEs presented a weaker dispersion capability at w/c = 0.29, but with a lower water-to-cement ratio (w/c), the hyperbranched PCEs exhibited a better dispersion capability than the comb-like PCEs. The dynamic light scattering (DLS) and transmission electron microscope (TEM) analysis showed that the adsorption layer of hyperbranched PCEs were thicker than that of comb-like PCEs. A thicker adsorption layer thickness generated thinner diffusion water layer thickness. The increase of the free water amount due to the thinner water diffusion layer is the key mechanism for improving the dispersibility and decreasing the viscosity of cement paste. [ABSTRACT FROM AUTHOR]

An attractive approach for the preparation of spirocyclic benzofuran–furocoumarins has been developed through iodine-catalyzed cascade annulation of 4-hydroxycoumarins with aurones. The reaction involves Michael addition, iodination, and intramolecular nucleophilic substitution in a one-step process, and offers an efficient method for easy access to a series of valuable spirocyclic benzofuran–furocoumarins in good yields (up to 99%) with excellent stereoselectivity. Moreover, this unprecedented protocol provides several advantages, including readily available materials, an environmentally benign catalyst, a broad substrate scope, and a simple procedure. [ABSTRACT FROM AUTHOR]

This paper takes 30 provinces in China as the research subjects and constructs a real options model to explore the impact of carbon emissions trading market, energy storage subsidies, and their synergy on the optimal investment decision of household PV-ESS projects. The results show that a single factor has a catalytic effect on project investment, and both together have a better effect. And, project investment benefits are better in areas with abundant light resources and higher than average electricity prices. In addition, a sensitivity analysis is conducted on the initial investment cost, CO 2 price, and energy storage subsidies. The results show that immediate investment in all provincial projects can be achieved when the initial investment cost is reduced by 50%, or the CO 2 price is increased by about 33 times, indicating that the current environment is insufficient to attract investors. The results provide a reference framework for investment in household PV-ESS projects. • Use real options methods to assess investment decisions for household PV-ESS projects. • Explore the role of carbon trading market and energy storage subsidies on investment. • Research the impact of different regional power grids on investment value. [ABSTRACT FROM AUTHOR]

This study introduces a new regional feed-in tariff (FIT) pricing mechanism for solar photovoltaic (PV) energy in China, informed by real option (RO) theory and incorporating the increasing significance of tradable green certificate (TGC) policy revenues. The mechanism aims to balance government and consumer burdens with investor benefits. By factoring in additional income from green certificate sales, the study calculates the internal rate of return (IRR) to fall between 8 and 16% and uses a Monte Carlo simulation to determine optimal FITs for 30 Chinese provinces. These optimal FITs are then compared with current FITs, which are categorized by three types of solar resource regions, revealing that many current FITs are set within an inappropriate range and require adjustment. Additionally, the study observes minor differences in provincial FITs within six regional power grids, suggesting that setting FIT guide prices at the regional grid level is more practical than by solar resource regions. A sensitivity analysis examines the impact of green certificate prices, carbon prices, and technological advancements on the FIT for solar PV, comparing scenarios in a realistic environment versus a more favorable one. The results indicate that in a better environment—with higher TGC and carbon prices and encouraged corporate innovation—the FIT for solar PV is closer to the cost of coal-fired electricity, thus promoting grid parity. The study advocates for adjustments to the FIT mechanism, higher TGC and carbon prices, and the encouragement of innovation to enhance the competitiveness of solar PV energy in China's energy market. [ABSTRACT FROM AUTHOR]

Ground granulated blast-furnace slag (GGBS) is widely used as supplementary cementitious material of interest for adjusting the performance of concrete. Unlike standard commercial products, characteristics of GGBS from different iron manufacturers vary significantly and assessment of its reactivity, especially at an early age, is not well-established despite numerous parameters specified in current standard systems. Three GGBSs with different setting features during the alkali-activated process were dissolved in either deionised (DI) water or NaOH solution in this study. To illustrate the fundamental processes of reaction kinetic, the dissolved ion concentrations, glassy structural changes, and chemically bound water were measured using ICP-OES, FTIR, and TG respectively. Meanwhile, thermodynamic calculations were carried out to estimate the precipitation of C–S–H gels, which is directly linked with setting behaviours. The results clearly show the differences in the dissolution of the three GGBSs, which could be used to indicate the activity of GGBS. The GGBS with higher activity (i.e. faster setting during alkali activation) tends to dissolve evenly in DI water, whilst those with lower activity show that the silicate groups with lower polymerisation dissolved faster. The chemically bound water determined by TG analysis and the effective saturation index (ESI) are promising parameters for reflecting the activity of GGBS during dissolution in the alkali media. Although this study demonstrated the dissolution rate of higher polymerised silicate groups in GGBS should be the root for the differences in its activity, more structural information on the glassy phase and the interactions of alkali with the surface of GGBS still require further understanding. It is speculated that the ratio of Al[IV]/Al[V] plays an important role in the activity of GGBS. This finding may shape a certain basic understanding of how GGBSs dissolve in neutral and high pH solutions and highlight a re-evaluation of assumptions in thermodynamic simulation under different conditions. [ABSTRACT FROM AUTHOR]

The addition of coarse aggregate in ultra-high performance concrete offers several benefits, including the reduction of self-shrinkage, cost reduction, and increased modulus of elasticity. However, it also affects the dispersion space of steel fibers, resulting in a combined effect that both enhances and limits their respective advantages. An image method was used to describe the dispersion of steel fibers and coarse aggregate in the specimens along their length, width and height directions, respectively. The impact of dispersion of steel fibers and coarse aggregate on bending performance was investigated by four-point bending tests using various surfaces as the bottom tensile zone. Furthermore, the damage occurrence mode and crack development process are discussed using micro-morphology and cross-sectional graphs. The results show that the combined effect of steel fibers and coarse aggregate is not conducive to dispersion in the length direction but prevents settling due to gravity during vibration. Differences in bending properties among various surfaces in the bottom tension zone was significant, but the synergy between steel fibers and coarse aggregate reduced these differences by 1.5–2.4 times. Steel fibers in ultra-high performance concrete containing coarse aggregate act as crack arrestors, resulting in ductile damage. Cracks develop partly through the coarse aggregate and partly along the interface transition zone, indicating that the addition of coarse aggregate does not compromise flexural strength. • Dispersion variability was observed in the length, width, and height directions, influenced by the combined effect. • The combined effect mitigated the settling of steel fibers in ultra-high performance concrete. • The coarse aggregate has a limited effect on the flexural strength but diminishes post-peak performance. • The dispersion of steel fibers is the primary factor influencing post-peak performance. • The combined effect reduced the variation in bending parameters for different surfaces acting as the bottom tension zone. [ABSTRACT FROM AUTHOR]