Air pollution poses significant health and economic challenges globally and specifically affecting China. Although air pollution has been associated with decreased productivity and biases in ...decision-making, its effect on the development of digital finance has received limited attention in the literature. By employing city-level data from China covering the period from 2013 to 2020, this research examines the impact of air pollution on digital finance. The results show that deteriorating air quality has a negligible impact on digitalization, whereas it has a negative impact on financial inclusion, measured by usage and coverage metrics. The negative impact on financial inclusion is more noticeable in economically weaker and less developed urban areas and low R&D than in developed areas and economically robust cities. The mechanism analysis shows that air pollution reduces human capital quality, resulting in a decline in financial inclusivity. These findings have significant policy implications, underscoring the necessity for approaches that simultaneously tackle air pollution and foster financial innovation.
With the increased demand for high operating temperature of gas turbine engines, corrosion by molten calcium-magnesium-alumino-silicate (CMAS) exhibits a significant challenge to the development of ...durable environmental barrier coatings (EBCs). EBC candidates, γ-Y2Si2O7, β-Yb2Si2O7, and β-Lu2Si2O7 were explored on their corrosion resistance to CMAS melts at 1300 °C and 1500 °C for 50 h. Interaction and degradation mechanisms were investigated and the corrosion behaviors showed different trends at high temperatures. At 1300 °C, RE2Si2O7 dissolves into CMAS melts and apatite phases reprecipitate forming a thick recession layer. However, when the temperature increases to 1500 °C, CMAS melts vigorously penetrate through the grain boundary of RE2Si2O7 and ‘blister’ cracks form throughout the samples. The reduced grain boundary stability at 1500 °C promotes the penetration of CMAS melts in RE2Si2O7. Grain boundary engineering is critically demanded to optimize CMAS corrosion at high temperatures.
Emerging economies are showing promising growth and economic success, but the growth process has significantly increased carbon emissions in these countries and deteriorated environmental quality. ...Environmental degradation is an issue of serious concern as it is directly linked to human lives and health. Since the creation of the Sustainable Development Goals (SDGs), the Emerging Seven (E-7) countries have struggled to meet the SDG targets, as it's been a challenge for them to lower carbon emissions and improve the quality of the environment. Thus, the present study explores the key factors that significantly affect environmental quality. This study examines the effect of institutional quality, energy productivity, and eco-innovation on consumption-based carbon dioxide (CCO
2
) emissions for E-7 economies. The cointegration analysis results show a long-run relationship between institutional quality, energy productivity, GDP, eco-innovation exports, imports, and CCO
2
emissions. The results obtained using the cross-sectionally augmented autoregressive distributed lag (CS-ARDL) model show that institutional quality, energy productivity, eco-innovation, and exports adversely affect CCO
2
emissions and improve environmental quality in the short and long run. In contrast, imports and GDP are positively linked with CCO
2
emissions and contribute to environmental degradation. Policies that target institutional quality, eco-innovation, and energy productivity significantly affect CCO
2
emissions and help improve environmental quality.
Rare earth (RE) silicates are promising candidates for environmental and thermal barrier coating (ETBC) materials. Low thermal conductivity is one of the main concerned thermal properties in ETBC ...design. We herein adopted multiple phonon scattering mechanisms to lower thermal conductivity of (YxYb1-x)2SiO5 solid solutions. Bulk samples were prepared by hot pressing method and RE atomic occupations, Raman spectra, thermal conductivities were measured as well as Debye temperature was obtained from temperature dependent Young's modulus. It is interesting to note that huge mass and size misfits between Yb and Y ions dominate the decrement of thermal conductivity. Furthermore, Yb2+ increases the concentration of oxygen vacancy, and it further decreases heat conduction. This work highlights the possible defect engineering in RE silicates for their advances in ETBC applications.
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RE2SiO5 with low thermal conductivity, compatible thermal expansion coefficients and excellent high-temperature reliability in harsh environments are excellent candidates as advanced ...environmental/thermal barrier coating materials for high-efficiency gas turbine engines. A series of rare earth silicates (HoxY1-x)2SiO5 are designed and their properties are comprehensively investigated in this paper. Through doping Ho into Y2SiO5, the thermal conductivity of Y2SiO5 is significantly decreased and the thermal expansion coefficient is also optimized closer to Si-based ceramics. High-temperature elastic stiffness and bending strength are increased with the enhancing of Ho content. Most important, doping Ho element provides (HoxY1-x)2SiO5 with tunable luminescence characteristic. (HoxY1-x)2SiO5 exhibit green, to yellow-green, then to orange-red luminescence color with increased Ho concentration. The results show that they can be used as damage self-monitoring environmental/thermal barrier coating materials for Si-based ceramics.
Abstract
Chemical looping processes based on multiple-step reduction and oxidation of metal oxides hold great promise for a variety of energy applications, such as CO
2
capture and conversion, gas ...separation, energy storage, and redox catalytic processes. Copper-based mixed oxides are one of the most promising candidate materials with a high oxygen storage capacity. However, the structural deterioration and sintering at high temperatures is one key scientific challenge. Herein, we report a precursor engineering approach to prepare durable copper-based redox sorbents for use in thermochemical looping processes for combustion and gas purification. Calcination of the CuMgAl hydrotalcite precursors formed mixed metal oxides consisting of CuO nanoparticles dispersed in the Mg-Al oxide support which inhibited the formation of copper aluminates during redox cycling. The copper-based redox sorbents demonstrated enhanced reaction rates, stable O
2
storage capacity over 500 redox cycles at 900 °C, and efficient gas purification over a broad temperature range. We expect that our materials design strategy has broad implications on synthesis and engineering of mixed metal oxides for a range of thermochemical processes and redox catalytic applications.
Titanium diboride (TiB2) was successfully hot‐pressed at 1500°C using titanium aluminum carbide (Ti3AlC2) as a sintering aid. The mechanisms for the improved sinterability of TiB2 by the addition of ...Ti3AlC2 involve, first, the Al coming from the decomposition of Ti3AlC2 can eliminate the oxide layer on the surface of TiB2; second, the TiCx (also from the decomposition of Ti3AlC2) has a positive influence on the densification of TiB2 due to its plasticity at high temperatures. TEM observations reveal that the interface between TiB2 and TiCx is coherent and strong, free of amorphous layers and oxide phases. An optimized composition of TiB2‐10 wt% Ti3AlC2 was obtained with the unique combination of mechanical properties, including the elastic modulus of 567 GPa, the fracture toughness of 4.8 MPa·m1/2, the flexural strength of 711 MPa, and the hardness of 25 GPa.
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•CAMS corrosion of RE2SiO5 is linearly related to RE ionic radius. This stands for an efficient materials selection for its EBC applications.•Smaller RE leads to the decreased ...reactivity and this brings out shallower recession layer and better resistance to CMAS.•Optical basicity difference between RE2SiO5 and CMAS can be used as an indicator for predicting their reactivity.
Thermochemical reactions between rare earth (RE) monosilicates (RE2SiO5) and molten calcium-magnesium-aluminosilicate (CMAS) at 1300 °C were investigated. Some RE2SiO5 (RE = Tb, Dy, and Ho) dissolve readily into CMAS melts and thereby, crystalline Ca2RE8(SiO4)6O2 reprecipitate. Other RE2SiO5 (RE = Tm, Yb, and Lu) resist CMAS attack, and a continuous layer of Ca2RE8(SiO4)6O2 establishes at the interface. The recession of RE2SiO5 is related to RE ionic radius. RE2SiO5 with small RE ionic radius exhibits good CMAS corrosion resistance due to its low reactivity with CMAS. This result is consistent with the same trend of difference in the optical basicity of RE2SiO5/CMAS.
Purpose
Prescribed fires or wildfires are common in natural ecosystems. Biochar input during fires can impact soil greenhouse gas (GHG) emissions, including methane (CH
4
), carbon dioxide (CO
2
), ...and nitrous oxide (N
2
O). Meadows are functionally important ecosystems due to their large carbon (C) and nitrogen (N) stocks and potential to mitigate GHG emissions. The effects of biochar on meadow GHG emissions may be sensitive to whether it is derived from more than one type of vegetation, especially with N addition and warming. To further our understanding of how input of fire-derived biochar affects meadow soil GHG emissions, especially under the context of N deposition and warming, we conducted this study to examine potential non-additive effects of these factors.
Materials and methods
We collected soils from meadows dominated by
Miscanthus sinensis
and
Arundinella hirta
at Wugong Mountain (Jiangxi, China). Biochar was produced by pyrolyzing the aboveground vegetation of each of the two species at 450 °C for 1 h. Mixed biochar was produced by 1:1 ratio. Soil GHG emissions and N transformations were measured by incubating soils with biochar (control,
M. sinensis
biochar,
A. hirta
biochar, mixed biochar) and N addition (control vs. 6 g m
−2
) treatments at different temperatures (10, 15, 20, or 25 °C).
Results and discussion
Biochar input consistently increased both CH
4
and N
2
O flux, but only
A. hirta
and mixed biochar decreased CO
2
emission rates. Mixed biochar imposed non-additive effects on cumulative CH
4
and CO
2
emissions. Biochar decreased soil nitrification rates and increased the temperature sensitivity of soil N
2
O emission rates. The results indicated that biochar input during fires in meadows impacts soil GHG emissions and N transformations. Input of biochar into meadow soil following fire impacted GHG emissions, and mixing biochar derived from different species imposed non-additive effects on CH
4
and CO
2
emissions.
Conclusions
The variable and non-additive biochar effects on soil GHG emissions showed that fire-induced alterations in meadow soil GHG emissions will depend on the species composition of the local plant community. The effects of biochar on meadow soil GHG emissions after fires should be considered in future budgets of meadow soil GHG emissions and prediction of prescribed fire impacts on meadow ecosystems under the context of N deposition and warming
.
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