Search results

The fabric self-lubricating liners are the key factors impacting the performances of self-lubricating spherical plain bearings. The purpose of this paper is to improve the friction and wear properties of self-lubricating radial spherical plain bearings by modification of the liners.

The liners of hybrid woven PTFE/Kevlar fabrics were treated respectively by the LaCl₃ and CeO₂ solutions. The tribological properties of self-lubricating spherical plain bearings with treated or untreated liners under continuous swaying conditions were investigated with the bearing tester at the swaying frequency of 2.5 Hz and the swaying angle of ±10°. The film formation and wear mechanisms were analyzed based on the observation of worn surfaces with a scanning electron microscope (SEM) and an energy dispersive spectrometer (EDS).

Results show that the tribological properties of the bearings treated by the LaCl₃ or CeO₂ solution were improved compared with those of the untreated bearings. In particular, the wear resistance of bearings treated by the CeO₂ solution was remarkably improved under higher swaying cycles, but the anti-friction properties and cooling effects of bearings treated by the LaCl₃ solution were better under lower swaying cycles. Through SEM analysis, the reasons were analyzed. The bearings with treated liners only produced slight adhesive and abrasive wear, but the bearings with untreated liners produced more serious adhesive and abrasive wear under higher swaying cycles.

The paper proposed a new pretreatment process for the self-lubricating liners. The investigation on the friction and wear behaviors of the bearings is beneficial for prolonging the service lives of the radial spherical plain bearings.

To address challenges such as inadequate funding and inefficiency in public infrastructure construction, PPPs have gained significant global traction. This study aims to comprehensively assess the impacts and mechanisms of PPPs on the SDI and to provide rational policy recommendations based on the findings.

We collated a dataset from 30 Chinese provinces covering the years 2005–2020 as our research sample. The study’s hypotheses are tested using a double fixed-effects model, a chained mediated-effects model and a multidimensional heterogeneity analysis.

Our findings indicate that PPPs have a facilitating effect on SDI in general. This boost usually lags behind policy implementation and is cyclical in the time dimension. In the spatial dimension, PPPs contribute significantly to SDI in the eastern and western regions, but not in the central region. From the perspective of the dynamics of economic, social and industrial development, PPPs in economically backward areas are difficult to promote SDI, promote it the most in economically medium regions and are slightly less in economically developed regions than in medium regions. This promotion effect has an inverted U-shaped relationship with social development and diminishes with industrial structure upgrading. Finally, due to the negative relationship between PPPs and social development and between social development and SDI, PPPs are shown to contribute to SDI and are identified as critical paths. However, PPPs suppress SDI by inhibiting economic and industrial development.

This study makes three novel contributions to the existing body of knowledge: (1) we innovatively introduce the United Nations Sustainable Development Goals (SDGs) into the field of infrastructure research, offering fresh perspectives on SDI enhancement; (2) revealing the mechanisms by which PPPs affect SDI through the three dimensions of economic, social and industrial development enabling policymakers to better understand and optimize resource allocation and improve planning, design and management of PPP projects for sustainable infrastructure and (3) we assess the spatiotemporal variances of PPPs’ effects on SDI and the diversity across regions at different social, economic and industrial structures developmental stages, offering critical insights to global decision-makers to devise tailored policy measures.

Agricultural science and technology (AST) often need the form of industry-university-research cooperation in successfully completing breakthrough agricultural technology innovations. Therefore, AST industry-university-research cooperation is not only the need of the AST development strategy in China but also the only way for the development of agricultural colleges and universities, agricultural scientific research institutions and agricultural enterprises. Among them, in the process of cooperative breakthrough agricultural technology innovation, the correct selection of partners is the basis for ensuring its effective operation.

Aiming at the time-series characteristics and information ambiguity of decision information in the dynamic selection process of AST industry-university-research partners, this research introduces the dynamic intuitionistic fuzzy multi-criteria decision-making method of time degree and orthogonal projection. On this basis, field theory is used to construct the cooperative innovation capability field model of the partners, and the threshold for the partners to enter or exit the system is designed to dynamically select and eliminate the partners.

Results show that this method fully considers the situation of cooperative innovation resources within the AST industry-university-research system and the resource complementarity of candidate partners.

Combined with examples from agricultural scientific research institutions, the applicability and superiority of the model are verified.