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This paper aims to investigate the effect of frictional heat on the wear of high-speed rotary lip seals in engines.

In this research paper, the authors focus on the high-speed rotating lip seal of aircraft engines. Using the hybrid lubrication theory, a thermal-fluid-solid coupled numerical simulation model is established to investigate the influence of parameters such as contact pressure distribution, temperature rise and leakage rate on the sealing performance under different operating conditions. By incorporating the Rhee wear theory and combining simulation results with experimental data, a method for predicting the wear of the rotating seal lip profile is proposed. Experimental validation is conducted using a high-speed rotating test rig.

The results indicate that as the speed increases, the rise in frictional heat leads to a decrease in the sealing performance of the lip seal contact region. The experimental results show a similar trend to the numerical simulation results, and considering the effect of frictional heat, the predicted wear of the lip seal profile aligns more closely with the actual wear curve. This highlights the importance of considering the influence of frictional heat in the analysis of rotating seal mechanisms.

This study provides a reference for the prediction of wear profiles of engine high-speed rotary lip seals.

This paper aims to focus on the high-speed rotary lip seal in aircraft engines, combining its service parameters, its own structure and application conditions, to study the influence of different eccentric forms, eccentricity, rotational speed and other factors on the performance of the rotary lip seal.

A numerical simulation model for high-speed eccentric rotary lip seals has been developed based on the theory of elastic hydrodynamic lubrication. This model comprehensively considers the coupling of multiple physical fields, including interface hydrodynamics, macroscopic solid mechanics and surface microscopic contact mechanics, under the operating conditions of rotary lip seals. The model takes into account eccentricity and uses the hazardous cross-sectional method to quantitatively predict sealing performance parameters, such as leakage rate and friction force.

Eccentricity has a large impact on lip seal performance; lips are more susceptible to wear failure under static eccentricity and to leakage failure under dynamic eccentricity.

This study provides a new idea for the design of rotary lip seal considering eccentricity, which is of guiding significance for the engineering application of rotary lip seal.

This paper aims to identify patterns in the career intentions of PhD students and explore factors influencing these patterns.

Based on data from the Nature 2019 global PhD survey, the paper uses latent class analysis to identify the number and types of patterns in PhD students’ career intentions. Multinomial logistic regressions are used to analyse the influential factors, and means comparisons are used to describe differences in study experiences among career intention patterns.

The paper reveals distinct career intentions among PhD students: Pure Academic Enthusiasts (25.60%), Research-Driven Flexibles (28.64%), Neutralists to Non-research (16.27%), Uncertain Career Explorers (13.63%) and Non-academia Pursuers (15.86%). Research-Driven Flexibles, inclusive of researching roles beyond academia, demonstrate similar engagement and academic skills but have more transferable skills compared to Pure Academic Enthusiasts. Uncertain Career Explorers express positivity but show relatively lower engagement and academic skills. Non-academia Pursuers spend above-average time on learning but have the weakest relationship with supervisors, participation in academic activities, campus environmental support and transferable skills. Older doctoral students with dual degrees are less likely to be Uncertain Career Explorers, while those motivated by academic interests are more likely to be Research-Driven Flexibles or Pure Academic Enthusiasts.

This study provides a more accurate multi-dimensional perspective of PhD students’ career intentions, extending previous research that focused solely on the type of work PhD students sought or the sector in which they desired to work.

The geological conditions of Longyang Reservoir are complex and it is located in strong earthquake area. In order to determine its seismic characteristics, the seismic response and residual deformation of embankment dam should be studied to provide calculation basis for dam design and construction.

Based on the geological survey data of Longyang Reservoir, the dam filling materials are tested by dynamic deformation tests, and the equivalent linear constitutive model parameters of the filling materials are obtained. Based on Duncan-Chang E-B model, the stress state of embankment dam in Longyang Reservoir before earthquake is calculated, and the dynamic response and earthquake residual deformation of embankment dam in Longyang Reservoir under earthquake condition are calculated by using equivalent linear model and Shen Zhu-jiang’s residual deformation model.

The results show that with the increase of dynamic shear strain, the dynamic shear modulus decreases and the damping ratio increases. The scatter plot between dynamic shear modulus and dynamic shear strain, and the scatter plot between damping ratio and dynamic shear strain under different confining pressures show strips. The calculation results shows that the acceleration of embankment dam in Longyang Reservoir increases with the increase of dam height, and the acceleration distribution has obvious amplification effect. Combined with the maximum dynamic shear strain during the earthquake and the state before the earthquake, the maximum vertical residual deformation of embankment dam in Longyang Reservoir is 2.98 cm which occurs at the top of the dam, calculated by the Shen Zhu-jiang’s residual deformation model.

Finite element calculation model parameters of embankment dam are obtained by dynamic triaxial tests. Seismic dynamic responses and residual deformation of embankment dam are analyzed. With the increase of dam height, the acceleration distribution shows an obvious amplification effect. The vertical displacement of embankment dam is larger along the dam axis and decreases in the upstream and downstream direction. The maximum horizontal displacement of embankment dam occurs in the middle of upstream and downstream dam slopes.

• (1)

  Finite element calculation model parameters of embankment dam are obtained by dynamic triaxial tests.

• (2)

  Seismic dynamic responses and residual deformation of embankment dam are analyzed.

• (3)

  With the increase of dam height, the acceleration distribution shows an obvious amplification effect.

• (4)

  The vertical displacement of embankment dam is larger along the dam axis and decreases in the upstream and downstream direction.

• (5)

  The maximum horizontal displacement of embankment dam occurs in the middle of upstream and downstream dam slopes.

Finite element calculation model parameters of embankment dam are obtained by dynamic triaxial tests.

Seismic dynamic responses and residual deformation of embankment dam are analyzed.

With the increase of dam height, the acceleration distribution shows an obvious amplification effect.

The vertical displacement of embankment dam is larger along the dam axis and decreases in the upstream and downstream direction.

The maximum horizontal displacement of embankment dam occurs in the middle of upstream and downstream dam slopes.

This paper examines firm-level accountability and performance implications under a state-dominated institutional environment, China, for firms engaged in the space economy. Extant studies on the rapidly evolving civil space economy predominantly focus on developed Western economies at national or sector levels, frequently ignoring alternative institutional contexts. Additionally, limited attention has been given to firm-level empirical evidence and analysis, including corporate social responsibility (CSR) practice-R&D quality relationships in the space economy. The paper addresses each of these areas.

This paper utilises multiple regression, propensity score matching and split sampling methods applied to a proprietary dataset of Shanghai and Shenzhen Stock Exchange-listed A-share firms. Results are robust to endogeneity issues, alternative measurement of dependent variables and sampling.

China’s space firms demonstrate superior CSR performance to their counterparts in other sectors, supporting CSR‘s role in maintaining legitimacy. Their CSR practices also positively contribute to firm patent quality. The link is more pronounced among firms facing higher economic policy uncertainty and for state-owned enterprises (SOEs). The latter is due to SOEs’ government support, advantages in financing and attracting and retaining a high-quality workforce.

This paper adds to discussion on major space power’s, by examining China’s state-dominated civil space sector. It also addresses a lack of empirical firm-level evidence on space firm behaviour by examining the impact of firm-level CSR practices on R&D quality outcomes, areas in which there is a limited literature.

This paper aims to explore the impact of green finance on the heterogeneity of enterprise green technology innovation and the underlying mechanism between them.

Using the data of China's A-share listed enterprises from 2008 to 2020 and the fixed effect model, the authors empirically explore the relationship and mechanism between green finance and green technology innovation by constructing the green finance index while considering both the quality and quantity of innovation.

The study suggests that green finance is positively related to the quality and quantity of enterprise green technology innovation, while green finance is more effective in stimulating the quality of green technology innovation than quantity. In addition, alleviating financial mismatch and improving the quality of environmental information disclosure are core mechanisms during the process of green finance facilitating green technology innovation. Furthermore, green finance exerts a more positive effect on the quality and quantity of green technology innovation with large-size enterprises, heavily polluting industries and enterprises in the eastern region.

This paper enriches the literature on green finance and green technology innovation and provides practical significance for green finance implementation.

By comparing and contrasting the two scenarios of power producers investing in renewable energy and electricity sellers investing in renewable energy, we explore the conditions under which profit growth and carbon emission reduction can be realized, and provide a theoretical basis for decision-making on renewable energy investment by electric power companies as well as for government policy formulation.

This paper constructs a game model of a grid supply chain consisting of a leader generator and a follower seller in the context of the C&T mechanism, considering two scenarios in which the generator and the seller invest in renewable energy. Conclusions are drawn by comparing and analyzing the equilibrium solutions in different scenarios.

The scenario where electricity sellers invest in renewable energy exhibits a higher investment volume compared to the scenario involving power generators. In scenarios where power producers invest in renewable energy, electricity sellers achieve lower profits than power generators, while scenarios with electricity seller' investments yield higher profits for them. Increasing the cost coefficient of renewable energy investment reduces investment volume, electricity prices and electricity demand, leading to decreased profits for electricity seller but increased profits for power generator. A rise in the preference coefficient for renewable energy results in increased profits for electricity seller but decreased profits for power generator.

Addressing a literature gap in the context of low carbon, this study examines the investment scenario of electricity sellers in low carbon technologies, complementing existing research focused on power generators and consumers. The findings enrich knowledge in low carbon investment. By analyzing the investment decisions of both power producers and electricity sellers, this study explores the practical implications of renewable energy investments on the decision-making and operational dynamics of power supply chain enterprises. It sheds light on their profitability and investment strategies.

To date, research on migration and entrepreneurship has rarely focused expat-preneurs. Based on recent developments in both fields, this paper aims to investigate the under-researched phenomenon of Chinese self-initiated expatriates who choose to temporarily live and do business abroad on their own volition.

To address this research gap, 15 in-depth semi-structured interviews with Chinese expat-preneurs living in Portugal were conducted, exposing their narratives about their multiple challenges.

The findings corroborate the theoretical need to look beyond narrow economic explanations for why individuals engage in transnational entrepreneurship and entrepreneurial itinerancy. A collective identity and ethnic community are important because they influence how opportunities are identified and pursued.

This is a qualitative and interpretative study in a limited geographical area, which does not intent to ensure generalizability. More research is needed to further understand the phenomenon of entrepreneurial itinerancy in Europe and among other ethnic communities.

The findings provide insightful inputs to Portuguese policymakers and locals on how to support ethnic entrepreneurship. Chinese expat-preneurs also benefit from understanding how to strength their ethnic social ties in connection with local communities.

This study contributes to the entrepreneurship and international mobility literatures by providing new insights into the nature and dynamics of Chinese “expat-preneurs”, including their entrepreneurial itinerancy, necessary to properly understand entrepreneurs’ diversity and assist in extending transnational entrepreneurial theory.

Strategic human capital analytics (SHCA) has proven to be promising for improved organizational performance; however, research remains unclear about its influence on new venture performance. Building on the dynamic capabilities view (DCV), this study investigates the relationship between SHCA and new venture performance via generative capabilities with the moderating role of dual nationality founding members.

A quantitative research study has been carried out. Data was collected via a survey form from 313 founding members of new tech ventures and analyzed using Hayes process macro model.

Research results show that the generative capability mediates the linkages between SHCA and new venture performance. Whereas, the dual nationality of a founding member strengthens the linkages between SHCA and generative capability due to their diverse perspective, larger networks, cognitive flexibility, and resilience, which are important for generative capabilities and SHCA.

The originality of these results lies in the exploration of the linkages between dual nationality and generative capability, as well as the special elements, such as diverse perspectives, larger networks, cognitive flexibility, and resilience, which are highlighted as possible advantages of dual nationality in the context of SHCA and new venture performance.

This study aims to develop synthetic ester lubricating oil using renewable sinapic acid as raw material, to explore the structural design and selection of raw materials for green, high-performance synthetic ester oils.

A series of the sinapate ester oils were synthesized through esterification and alkoxylation reactions using renewable source sinapic acid as the raw material. The molecular structures of the oils were characterized by nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy spectroscopy and elemental analysis. The oils were evaluated for safety, viscosity-temperature properties, thermal and oxidative stability, as well as friction reducing and anti-wear characteristics.

Compared to commercial base oil tris (2-ethylhexyl) trimellitate (Phe-3Ci8), the bio-lubricant exhibits superior antifriction and anti-wear properties. Notably, the JCi8-C12 sample performed exceptionally well, reducing the friction coefficient by 11.42% and wear volume (WV) by 54.44% in steel/steel tribo-pairs. In steel/aluminum tribo-pairs, the friction coefficient decreased by 27.48%, while WV was reduced by 85.81%. Mechanistic studies reveal that the introduction of short-chain methoxy groups and stable conjugated systems (aromatic rings and double bonds) inhibit oxidation and decomposition at elevated temperatures. The p-p stacking effect enables lubricant molecules to arrange stably on friction surfaces, forming a durable lubricating film.

The utilization of biomass resources to develop green synthetic lubricating oil with excellent performance not only enhances the added value of waste from agricultural processing but also offers significant benefits in terms of both economic and environmental sustainability.