System Reliability and Component Importance Under Dependence: A Copula Approach

<p>System reliability and component importance are of great interest in reliability modeling, especially when the components within the system are dependent. We characterize the influence of dependence structures on system reliability and component importance in coherent systems with discrete marginal distributions. The effects of dependence are captured through copula theory. We extend our framework to coherent multi-state system. Applications of the derived results are demonstrated using a Gaussian copula, which yields simple interpretations. Simulations and two examples are presented to demonstrate the importance of modeling dependence when estimating system reliability and ranking of component importance. Proofs, algorithms, code, and data are provided in supplementary materials available online.</p

Porosity Enhancement of Carbazolic Porous Organic Frameworks Using Dendritic Building Blocks for Gas Storage and Separation

We report a facile synthesis of carbazolic porous organic frameworks (Cz-POFs) via FeCl₃ promoted oxidative polymerization. Using bulky, dendritic building blocks with high connectivity, the porosity of Cz-POFs was significantly enhanced. Specifically, Cz-POF-1 and Cz-POF-3 show high surface areas of 2065 and 1927 m² g^–1, respectively. These surface areas are 3.1 and 2.1 times larger than those of Cz-POF-2 and Cz-POF-4 constructed from less branched building blocks, respectively. At 1 bar and 273 K, Cz-POF-3 exhibits the highest CO₂ uptake (21.0 wt %) and CH₄ uptake (2.54 wt %), while Cz-POF-1 has the highest H₂ uptake (2.24 wt %) at 77 K. These values are among the highest reported for porous organic polymers. In addition, Cz-POFs exhibit good ideal CO₂/N₂ selectivities (19–37) and CO₂/CH₄ selectivities (4.4–7.1) at 273 K, showing great promise for gas storage and separation applications

A Novel Method for Performance Rejuvenation of WO₃//NiO Electrochromic Devices: Lithium Ion Kinetic Behavior with Variable Cycling Temperature and Switching Voltage

Electrochromic devices (ECDs) have great potential in energy efficient buildings, which may suffer from electrolyte ionic-trapping-caused invalidation of optical transmittance and charge capacity, though research is lacking on the migration regularity of electrolyte ions and the mechanism of performance recovery. In this paper, we investigate the combined effects of the cycling temperature and switching voltage on WO3//NiO solid-state devices. The relationship of temperature–voltage–Li+ concentration of ECDs is supposed to be established by exploring the activation and energy barrier for Li+ migration during the electrochromic process, providing quantitative information to optimize factors such as charge capacity, coloring efficiency, and lifetime, hence obtaining a novel strategy for ECDs performance recovery. Here we demonstrate that degraded ECDs can be rejuvenated by continuous cycling at 50 °C with the switching voltage of −1.4 V/ +1.4 V, thus regaining their initial electrochromic performance

Relationship between environmental regulation and carbon emission efficiency.

Relationship between environmental regulation and carbon emission efficiency.</p

A comparative study on fatigue indicator parameters for near‐<i>α</i> titanium alloys

Nucleation of in‐service cracks leads to detrimental consequences for structural components of near‐α titanium alloys subjected to fatigue loads. Experimental observations show that the fatigue initiation facets usually form in certain crystallographic orientation ranges of “hard” primary α grains which differ between pure and dwell fatigue loads. In this manuscript, a comparative study has been performed using several fatigue indicator parameters (FIPs) to assess their ability to predict the location of fatigue crack nucleation in near‐α titanium alloy microstructures. All selected FIPs are implemented within the same polycrystalline plasticity finite element modeling framework to facilitate one‐to‐one comparisons. Comparison on predictability of critical initiation locations and their crystallographic orientations is studied for incorporated FIPs under pure and dwell fatigue. The critical locations predicted by some FIPs were found to be close to each other, and consistent with the crystallographic orientation ranges from fractography measurements, in addition to the range transition from pure to dwell fatigue loads. Critical locations from slip driven FIPs are obtained to be several grains away from that of the former ones and are inclined to capture orientations of slip traces from experiments.</p

Results of parallel trend test.

The X-axis denotes the window period for PLSA implementation. The Y axis represents the regression coefficient of PLSA implementation. The year before PLSA is implemented as the base period.</p

Re-estimation of different dependent variable.

China’s economy experienced great growth, which also induces large carbon emission. Facing the target of “Carbon peak, Carbon neutrality” in China, it is vital to improve the carbon emission efficiency. Employing the spatial Difference-in-Differences model, this paper investigates the impact of environmental regulation on carbon emission efficiency with a quasi-natural experiment of Pollution Levy Standards Adjustment in China. Our empirical results show that the environmental regulation can significantly improve the carbon emission efficiency. moreover, two impact channels are explored: green innovation and industrial upgrading. More specifically, the green innovation increases with environmental regulation, and the increased green innovation improves carbon emission efficiency. The industry upgrading increases with environmental regulation, and the increased industry upgrading improves carbon emission efficiency. Finally, in terms of city heterogeneity, we find that the impact of environmental regulation will be more pronounced for larger cities and resource-based cities. Our findings suggest that the environmental regulation must be enhanced for both smaller cities and non-resource-based cities. Moreover, to promote the green innovation of firms, since green innovation is risky and costly, governments should provide more subsidies or grants on corporate green technologies, thus firms will be motivated to invest in green technologies to reduce carbon emission.</div

Descriptive statistics.

China’s economy experienced great growth, which also induces large carbon emission. Facing the target of “Carbon peak, Carbon neutrality” in China, it is vital to improve the carbon emission efficiency. Employing the spatial Difference-in-Differences model, this paper investigates the impact of environmental regulation on carbon emission efficiency with a quasi-natural experiment of Pollution Levy Standards Adjustment in China. Our empirical results show that the environmental regulation can significantly improve the carbon emission efficiency. moreover, two impact channels are explored: green innovation and industrial upgrading. More specifically, the green innovation increases with environmental regulation, and the increased green innovation improves carbon emission efficiency. The industry upgrading increases with environmental regulation, and the increased industry upgrading improves carbon emission efficiency. Finally, in terms of city heterogeneity, we find that the impact of environmental regulation will be more pronounced for larger cities and resource-based cities. Our findings suggest that the environmental regulation must be enhanced for both smaller cities and non-resource-based cities. Moreover, to promote the green innovation of firms, since green innovation is risky and costly, governments should provide more subsidies or grants on corporate green technologies, thus firms will be motivated to invest in green technologies to reduce carbon emission.</div

S2 Data -

China’s economy experienced great growth, which also induces large carbon emission. Facing the target of “Carbon peak, Carbon neutrality” in China, it is vital to improve the carbon emission efficiency. Employing the spatial Difference-in-Differences model, this paper investigates the impact of environmental regulation on carbon emission efficiency with a quasi-natural experiment of Pollution Levy Standards Adjustment in China. Our empirical results show that the environmental regulation can significantly improve the carbon emission efficiency. moreover, two impact channels are explored: green innovation and industrial upgrading. More specifically, the green innovation increases with environmental regulation, and the increased green innovation improves carbon emission efficiency. The industry upgrading increases with environmental regulation, and the increased industry upgrading improves carbon emission efficiency. Finally, in terms of city heterogeneity, we find that the impact of environmental regulation will be more pronounced for larger cities and resource-based cities. Our findings suggest that the environmental regulation must be enhanced for both smaller cities and non-resource-based cities. Moreover, to promote the green innovation of firms, since green innovation is risky and costly, governments should provide more subsidies or grants on corporate green technologies, thus firms will be motivated to invest in green technologies to reduce carbon emission.</div