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This paper aims to experimentally investigate the film-forming capability of base oils containing poly-methacrylate (PMA) and poly-isobutene (PIB), in a point contact under pure rolling.

By using the relative light intensity method, the film thickness is calculated from the interferometer images which are captured by multiple-contact optical elastohydrodynamic lubricated test rig.

The test results reveal that polymers, both PMA and PIB, have a significant contribution to the film-forming capability of base oils and the film thickness increases with concentration. The forming-film capabilities for PMA and PIB in base oils are similar at low concentration, while PIB gives a higher film thickness than PMA at high concentration. Shear-thinning phenomenon are observed in all polymer-based oils.

The polymer usually as an additive is added into the low viscosity base oils to improve the properties of lubricant oil. This paper reports the lubricated properties of PMA and PIB with different concentrations in base oils and to evaluate their functional mechanism in a point contact.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0263/

The purpose of this paper is to study starvation in grease-lubricated finite line contacts and to understand film-forming mechanisms of grease-lubricated finite line contacts.

A multiple-contact optical elastohydrodynamic (EHL) test rig is constructed to investigate the influences of lubricant properties on film thickness and lubrication conditions at different working conditions. The film thickness is calculated according to the relative light intensity principle. The degree of starvation is evaluated by the air–oil meniscus distance and the corresponding film thickness.

The experimental results show that for greases with high-viscosity base oil, the high-frequency fluctuation of film thickness is observed in low-speed operating conditions. Reducing the viscosity of the base oil and improving running speed can weaken the fluctuation of film thickness. The degree of starvation increases with increasing base oil viscosity, rolling speed and the crown drop. In addition, reducing the replenishment time by reducing the gap between the rollers also can increase the degree of starvation.

Starvation is often to occur in finite line contacts, such as roller bearings and gears; there are still limited finite line contact EHL test rigs, much less multiple-contact optical test rigs. Therefore, the present work is undertaken to construct the multiple-contact test rig and to evaluate the mechanism of starvation in finite line contacts.

A flipped classroom refers toa model of learning which reverses how time is spent in and out of the class to shift the ownership of learning from the teachers to learners. But from the perspective of ecology, education can be healthily developed in a harmonious and dynamically-balanced ecological system. Therefore, this project, exemplified through translation teaching, constructed a flipped teaching model based on an ecological perspective that open university distance learners will adapt to after revisiting the flipped classroom. Through the teaching experiment in the course on Translation Theory and Practice, the author highlighted that a good ecological relationship should be established in the translation subject, the translation object, the objectives of the translation course, and translation sources and requirements from the translation market — based on which the basic teaching process of a flipped classroom was developed. Using a questionnaire and interviews, the results of a one-year experiment showed that the flipped teaching model with the integration of modern information technology (functions of interaction, virtual simulation and social networking) in translation teaching could foster greater student engagement and higher levels of motivation and translation competence; and the teachers were excited by the opportunity to enhance their teaching practice and the profession. However, some major challenges were also posed to the students and teachers, viz.: (1) how to make the students transform from knowledge-receivers to knowledge-producers; and (2) how to improve the teacher's TPACK(technology integrated into some curricula) — for example,how to explaina concept in a bite-sized video (the pace, the visual representation, and the aligned assessment practices) and how to extend these activities into the classroom.

This study aims to investigate the effect of top management team (TMT) stability on outward foreign direct investment (OFDI) of Chinese firms and the moderating effects of state ownership and managerial ownership on this relationship.

An empirical analysis based on the ordinary least square regression model is conducted using Chinese A-share listed firms that engaged in OFDI from 2008 to 2021.

TMT stability has a positive effect on firms’ OFDI. Moreover, state ownership significantly strengthens the positive relationship between TMT stability and OFDI, while managerial ownership weakens this positive relationship.

The findings help firms to effectively retain TMT talents and promote the smooth internationalization of firms, thereby enhancing their long-term development capabilities and competitive advantages.

This study expands the investigation of the factors influencing OFDI at the micro level of the TMT, providing valuable decision-making insights for firms.

This paper aims to focus on the preparation of Kevlar fiber (KF) and alkaline hydrolyzed KF (KF-H) to improve the dispersed condition of polyaniline (PAn), as the aggregation of PAn would lead to some adsorption sites buried. And then the materials were used to enrich anionic dye Congo red (CR) from aqueous solution.

The materials (KF@PAn and KF-H@PAn) were designed by means of “diffusion-interfacial-polymerization” under mild condition as high affinity due to the structural properties of PAn, KF and KF-H. The dispersed degree of PAn on the surface of KF and KF-H was validated according to adsorption efficiency for CR.

The content of PAn introduced was not beyond 20 wt.%, while adsorption capacity for CR was significantly enhanced by 4–8 times (on the basis of kinetic data) according to the calculation only by the content of PAn due to KF and alkaline hydrolyzed KF exhibited almost no adsorption for CR, indicating dispersed situation of PAn coating was greatly enhanced and more active sites exposed, which was favorable for the adsorption process. Presence of NaCl would exhibit a more or less positive effect on CR uptake, suggesting the materials could be used for high salt environment.

The investigated means of dispersed degree of PAn on the surface of KF and KF-H are the further and future investigation.

This study will provide a method to improve the dispersed situation of PAn and a theoretical support to treat anionic dyes from aqueous solution especially for salt environment.

The results showed that the dispersed condition of PAn on the surface of KF and KF-H was greatly improved. According to the adsorption capacities for CR, it can be concluded that part of adsorption sites were buried due to the aggregation of PAn, and introduction of KF and KF-H, buried adsorption sites decreased greatly. This study will provide a method to decrease buried adsorption sites of PAn and a contribution for their convenient application in wastewater treatment especially for high salt environment.