Dynamics optimization of helicopter main transmission system -- for multi-parameter and multi-condition coupled system
Peer-Reviewed Publication
Updates every hour. Last Updated: 21-Jun-2025 04:10 ET (21-Jun-2025 08:10 GMT/UTC)
To reduce the vibration of the coaxial helicopter main transmission system considering both level and vertical flight conditions, a vibration evaluation and optimization model was built. A vibration simulation model and a vibration evaluation method was established. A hybrid Gravitational Search Algorithm-Simulated Annealing (GSA-SA) algorithm was combined to balance convergence speed and searching accuracy. The principle test was conducted to prove the accuracy of theoretical method. The optional results show that the vibration of the optimized transmission system decreases significantly, in which the maximum reduction of key vibration indicators reaches more than 20%. The proposed method could be extended to other fields.
Propeller-driven aircraft are gaining renewed attention for sustainable aviation. Yet balancing efficiency with noise reduction remains a critical challenge—especially for emerging platforms such as eVTOL and hybrid-electric aircraft. Researchers from Nanjing University of Aeronautics and Astronautics have developed a new optimization framework based on the unsteady adjoint method that successfully addresses this trade-off. Their work offers a powerful tool for designing quieter, more efficient propellers, paving the way for the next generation of low-emission, low-noise aviation.
Aero-engine hot-end components face grinding challenges due to superalloys' low thermal conductivity, causing high heat, energy consumption, and reliance on unsustainable cooling. Ultrasonic vibration-assisted grinding (UVAG), heat pipe grinding wheels (HPGW), and minimum quantity lubrication (MQL) have been proposed to integrate to reduce heat generation, enhance heat dissipation, and minimize coolant use. In this case, the high-efficiency and sustainable grinding can be achieved with improved surface integrity.
Abstract
Purpose – This study examines the impact of ESG lending and technology-related capital expenditures on banking performance in BRICS economies. It assesses how these factors influence return on risk-weighted assets and nonperforming loans, providing insights into the role of sustainable finance and digital transformation in banking stability.
Design/methodology/approach – Using quarterly panel data (2015–2023) from commercial banks in Brazil, Russia, India, China and South Africa (BRICS), this study employs fixed-effects regression models to estimate the effects of ESG lending and technology investment on banking performance. A robustness check is conducted by segmenting the sample into large and small banks to assess the moderating role of institutional scale.
Findings – The results indicate that greater exposure to high-ESG firms enhances banking performance by improving RoRWA and reducing NPLs. Similarly, borrowers investing in technology exhibit more substantial financial stability, leading to lower credit risk for banks. The effects are more pronounced in smaller banks, suggesting that sustainable and technology-driven lending strategies provide greater risk mitigation benefits for institutions with resource constraints.
Practical implications – The findings highlight the strategic importance of integrating ESG and technology factors into banking credit risk frameworks. Banks should develop specialized financial products and enhance ESG and technology-based credit assessments to optimize lending strategies. Policymakers should introduce incentives to promote sustainable finance, encourage digital transformation and standardize ESG reporting across emerging markets.
Originality/value – This study contributes to the sustainable banking literature by jointly examining the impact of ESG and technology investments on banking performance in emerging economies. It provides empirical evidence from BRICS, highlighting the role of institutional scale in shaping the effectiveness of sustainable finance strategies. The results offer actionable insights for banks and regulators seeking to balance financial performance and sustainability in high-growth but volatile markets.
Abstract
Purpose – This study examines the convergence of energy diversification, financial development and per-capita income in OECD countries.
Design/methodology/approach – The research employs the club convergence test to assess convergence among OECD countries and uses Granger causality tests and panel regressions to identify the determinants of convergence, using data from 1997 to 2021.
Findings – The convergence tests showed no overall convergence but revealed convergence clubs for each factor. Granger causality tests indicated short-run bi-directional relationships between the variables. Long-run panel regression analysis confirmed that technological progress significantly improves per capita income and energy diversification. Additionally, it revealed bi-directional relationships between energy diversification and financial development, a uni-directional relationship from financial development to per capita income and a U-shaped effect of per capita income on energy diversification, with a turning point at $67,112.8 per year.
Practical implications – The findings suggest that within each convergence club, implementing microeconomic incentives for technology development and diffusion in energy, production, and financial services could help lagging countries catch up.
Originality/value – This study pioneers the testing of convergence in energy diversification, financial development and per capita income in OECD countries and identifies the determinants of this convergence.
Recently, Xie Zhen's team from Tsinghua University published a research article titled "SPECIFIC: A systematic framework for engineering cell state-responsive synthetic promoters reveals key regulators of T cell exhaustion" in Quantitative Biology, proposing an integrated framework combining chromatin accessibility analysis and machine learning for rational design of synthetic promoters.
What has been the trajectory of water erosion model research in China? What are the most widely used models currently? What are the characteristics of research distribution across different regions? What shortcomings need urgent attention? Professor Qingfeng Zhang from Northwest A&F University, along with researchers from multiple institutions, systematically reviewed the research progress of water erosion models in China from 1982 to 2022 using a combination of bibliometric and statistical analysis methods, providing a panoramic perspective to answer these questions. Relevant study has been published in the journal Frontiers of Agricultural Science and Engineering (DOI: 10.15302/J-FASE-2024580).