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[Objective] In the context of the “dual-carbon” goal, accurately assessing the status, rate and potential of carbon sequestration in terrestrial ecosystems is crucial for achieving “carbon neutrality”. Shaanxi Province, which spans three climatic zones and have a large difference in climate between north and south, with abundant vegetation types. In recent years, the vegetation coverage in Shaanxi has been further improved due to the implementation of various ecological projects (Grain for Green, Three-North Shelterbelt, etc.). Its vegetation coverage reaches up to 60.7%, what resulted in huge carbon sequestration capacity. Net primary productivity (NPP), as one of the most important indicators to reflect the carbon sequestration capacity of vegetation, there are few studies on spatial and temporal dynamic changes of NPP and the spatial distribution of NPP potential in the future in Shaanxi province. [Methods] Based on these, we evaluated the temporal and spatial distribution characteristics of vegetation NPP and its potential in Shaanxi province through the CASA model and the neighborhood similarity spatial distribution method. [Results] (1) Total carbon sequestration by vegetation increased by 333 Tg, with an increase of 48.5% from 2000 to 2020 in Shaanxi province. (2) NPP was higher in the south and lower in the north, with the highest or lowest value in the middle. The average value in 2000 and 2020 were 333.2 g C/m2 and 494.8 g C/m2, respectively, with a total increasement of 161.6 g C/m2, and the increase amplitude showed a distribution trend of high in the north and low in the south in Shaanxi. (3) The carbon sequestration potential was 2 304 Tg which increased by 41.30% compared with the 2020. The spatial distribution trend was gradually decreasing from south to north, and the spatial distribution characteristics showed high spatial autocorrelation characteristics, but the local differences were large. [Conclusion] The total vegetation carbon sequestration in Shaanxi province increased significantly from 2000 to 2020, and there is huge potential for vegetation carbon sequestration in the future. This study calculated the spatial and temporal dynamic changes and predicted potential spatial distribution characteristics of NPP in the regional scale ecosystem in Shaanxi province, which can provide an evaluation systematic and theoretical reference for scientific evaluation and improvement of regional carbon sink capacity.

We investigate the statistical properties of kinetic ϵu and thermal ϵ θ energy dissipation rates in two-dimensional (2D) thermal vibrational convection (TVC). Direct numerical simulations were conducted in a unit aspect ratio box across a dimensionless angular frequency range of 10 3 ≤ ω ≤ 10 7 for amplitudes 0.001 ≤ a ≤ 0.1 , with a fixed Prandtl number of 4.38. Our findings indicate ϵu is primarily associated with the characteristics of the vibration force, while ϵ θ is more related to the large-scale columnar structures. Both energy dissipation rates exhibit a power-law relationship with the oscillational Reynolds number R e os . ϵu exhibits a scaling relation as ⟨ ϵ u ⟩ V , t ∼ a − 1 R e os 0.93 ± 0.01 , while ϵ θ exhibits two distinct scaling behaviors, i.e., ⟨ ϵ θ ⟩ V , t ∼ a − 1 R e os 1.97 ± 0.04 for R e os < R e os , cr and ⟨ ϵ θ ⟩ V , t ∼ a − 1 R e os 1.31 ± 0.02 for R e os > R e os , cr , where the fitted critical oscillational Reynolds number is approximately R e os , cr ≈ 80. The different scaling of ⟨ ϵ θ ⟩ V , t is determined by the competition between the thermal boundary layer and the oscillating boundary layer. Moreover, the probability density functions (PDFs) of both dissipation rates deviate significantly from the lognormal distribution and exhibit a bimodal shape. By partitioning the contributions from the boundary layer and bulk regions, it is shown that the bulk contributes to the small and moderate dissipation rates, whereas the high dissipation rates are predominantly contributed by the boundary layer. As R e os increases, the heavy tail of the PDFs becomes more pronounced, revealing an enhanced level of small-scale intermittency. This small-scale intermittency is mainly caused by the influence of BL due to vibration. Our study provides insight into the small-scale characteristics of 2D TVC, highlighting the non-trivial scaling laws and intermittent behavior of energy dissipation rates with respect to vibration intensity. [ABSTRACT FROM AUTHOR]

A disassembly line is an effective disassembly system to recover end-of-life products. In real life, as end-of-life products are subject to varying degrees of wear and tear, task failure may occur in the disassembly process. In this paper, the task failure risks are considered, and an expected profit-based stochastic disassembly line balancing problem is studied. First, a mathematical model is presented to maximise the expected recovering profit with task failures. Then, a hybrid metaheuristic approach is developed to efficiently solve the proposed model, which is integrated with a variable neighbourhood descent method and an artificial bee colony algorithm. Finally, the effectiveness and robustness of the proposed algorithm are verified by three cases, and experiment results show that the solution performance of the proposed approach is superior to the other three existing methods. [ABSTRACT FROM AUTHOR]