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The COVID-19 epidemic has had an unexpected impact on global carbon emissions. In this context, carbon emission prediction is very important for policy formulation and implementation. It is worth pondering how the grey model deals with the prediction of unexpected events. Considering the spatial dependence of carbon emissions, this paper improves the multivariate grey model, gives new information a higher reference weight, and constructs a metabolic multivariate grey model -MMGM(1,m | λ) which takes new information as the priority. An optimization algorithm is constructed with the minimum error as the goal to determine the value of the weight adjustment parameter λ. Then we simulate and predict the carbon emissions of three regions: China's Yangtze River Delta (Shanghai, Jiangsu, Zhejiang, and Anhui), the North American Free Trade Area (Canada, Mexico, and the US), and West Europe (the UK and France). These three cases have different regions, different numbers of behavioural variables, different degrees of influence by COVID-19, and different trends, which are comparative. The results show that the new model has a good fitting effect, and it is still applicable in dealing with unexpected events. The new model can reflect regional carbon emission changes more systematically and accurately. Finally, according to cases and discussions, we get some management enlightenment to promote regional environmental collaborative governance. [ABSTRACT FROM AUTHOR]

Abstract: We unexpectedly discover that there are much lower GC3 and GC-content and higher Gibbs free energy on editing exons than other exons in the Drosophila synaptotagmin I transcripts, which was further, confirmed statistically by others 47 experimentally-validated samples. Sequence alignment, Ks and Ka/Ks assays suggest that rapidly ascending purifying selection occur in editing exons which constrains nucleotide divergency. The presence of specific molecular characteristics such as lower GC-content in editing exons imply an unexpected requirement and are likely to direct RNA editing occurrence. Thus, relations between molecular characteristics of DNA, RNA editing and purifying selection might be present. [Copyright &y& Elsevier]

The dynamical evolution of geostationary transfer orbits (GTOs) is a fundamental issue for the space debris mitigation in this orbit region. In this paper, the long-term dynamical evolution and orbital lifetime of low-inclination GTOs are investigated based on the Semi-analytic Tool for End of Life Analysis software (STELA) with the solar radiation pressure (SRP) and Earth's shadow taken into account. We carry out numerical investigations of long-term orbital evolution of objects with area-to-mass ratio (A/m) between 0.02 m2/kg and 1 m2/kg in the GTO region. Their dynamical orbital lifetime is recorded and presented in the Ω– ω (right ascension of ascending node–argument of perigee) plane to investigate its dependence on the initial conditions and physical parameters, particularly the initial azimuth of the Sun with respect to the apsidal line and the value of A/m. Based on these results, we further analyze the effect of SRP on the long-term dynamical evolution, as well as the solar apsidal resonances. The results are helpful to enrich the knowledge about long-term evolution and orbital lifetimes of GTO objects with relatively high A/m as well as to promote uncatalogued objects observation and identification. • The long-term evolution of low-inclination GTOs with medium area-to-mass ratio is investigated. • The coupling effect of SRP and other perturbations on the orbital lifetime is analyzed. • The dependency of orbital lifetime on the initial conditions is revealed. • The effect of SRP on the solar apsidal resonance is revealed in details. [ABSTRACT FROM AUTHOR]

Thermoplastic carbon fibre reinforced polyetheretherketone (CF/PEEK) and thermoset CF/epoxy composites have been widely applied in various industries. However, there is still a lack of knowledge concerning the milling performance and residual mechanical behavior of these two types of composites. To address this issue, we conducted a comprehensive investigation of the machinability during milling of both composites, with a focus on cutting force, machining temperature, chip characteristics, and milling-induced damages. To our knowledge, this is the first report documenting the correlation between surface integrity under different cutting conditions and residual tensile behaviour in both composites. The results demonstrate that CF/PEEK exhibits better machining quality than CF/epoxy due to its ductile matrix and strong interface bonding with fibres. Furthermore, down-milling was found to be preferable to up-milling for minimizing top layer surface damage, while petal-shaped chips with good integrity were found to be generated by CF/PEEK during milling. Moreover, CF/PEEK exhibited a significantly higher residual tensile strength (12.05%–63.22%) compared to CF/epoxy. • This study provides the investigation of milling performance in CF/PEEK and CF/epoxy, filling a knowledge gap. • The effects of two milling strategies on damages were systematically investigated to obtain preferable milling strategy. • The findings on residual tensile strength indicated that CF/PEEK has significantly higher resilience compared to CF/epoxy. [ABSTRACT FROM AUTHOR]

Due to the excellent properties of PEEK and their widely applications in medical industry, it is necessary to conduct a comparative study into the drilling performance and residual tensile behavior of PEEK plates under varying cutting conditions. In this study, the effects of tool geometry, drilling parameters, and slope angles on the thrust force, tool temperature, hole quality are discussed. The residual tensile behavior of the drilled PEEK plates is elucidated in terms of the full-field strain evolution during tensile testing by the Digital Image Correction system. The results showed that drilling parameter and tool geometry affect significantly cutting forces, tool temperature, and resulting hole quality. The relationship between the machinability and the residual tensile property of PEEK is reported for the first time. Full-field strains during tensile testing are sensitive to the level of drilling-induced damages, which have an impact on the residual tensile property of PEEK components. • The relationship between the machinability and the residual tensile property of PEEK is reported for the first time. • The cutting performance of tool geometry on perpendicular and non-perpendicular drilling was systematically investigated. • The crescent drill can reduce cutting forces and tool temperature, improve hole quality and the residual tensile strength. [ABSTRACT FROM AUTHOR]

Abstract: To date great efforts have been devoted to the development of solid oxide fuel cell (SOFC) devices that is able to run at intermediate temperature (IT) and to retain good electrochemical performance as in the high temperature regime. To this end, Tantalum (Ta) is doped into Sr2Fe1.5Mo0.5−x Ta x O6−δ (0.0 ≤ x ≤ 0.15) to further improve the electrochemical performance as the cathode materials for IT-SOFC. Pure orthorhombic Sr2Fe1.5Mo0.5−x Ta x O6−δ (0.0 ≤ x ≤ 0.15) samples, with space group Pnma (no. 62), are synthesized by a two-step method and identified via the powder X-ray Rietveld refinements. X-ray photoelectron spectroscopy and thermogravimetry results consistently show that the number of oxygen vacancy increases with the increasing of Ta content. The thermal expansion compatibility of the samples is found to match the electrolyte of La0.9Sr0.4Ga0.1Mg0.2O3−δ (LSGM) better than that of cobalt-containing electrode compounds. Finally, the higher oxygen vacancy concentration leads to the enhanced ionic conductivity although electrical conductivity is slightly decreased due to the oxygen vacancy blocking. Therefore, Ta-doped Sr2Fe1.5Mo0.5O6−δ is proved to be a promising candidate for future cathode materials of IT-SOFC. [Copyright &y& Elsevier]