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This chapter presents a study on the work of commercial diplomats as international business promoters at foreign posts. Research has largely overlooked the actual roles and activities of commercial diplomats in explaining the effectiveness of commercial diplomacy and international business support. In this study, it is assumed that commercial diplomats’ behavior is influenced by informal institutions. Face-to-face semi-structured interviews with 23 commercial diplomats at foreign posts from different countries were conducted and analyzed. The results show three different types of role behavior and differences in proactivity per type. Informal institutions such as background, skills, and experience, cultural differences, and the working environment suggest to explain the differences in levels of proactive international business support behavior of commercial diplomats. Further research is needed to assert these findings.

This study aims to form composite solid lubricant coatings on the surface of bearing steel, which can significantly improve the tribological properties of thrust cylindrical roller bearings (TCRBs). Phosphating films possess microscopic porosity that typically needs to be sealed with oil, grease or wax. Due to its unique crystal structure, the phosphating film itself also exhibits a certain degree of lubricity. In this study, solid lubricants are used to fill the pores of the phosphating film. By combining the phosphating film with solid lubricants, lubrication and wear reduction can be achieved.

In this study, the surfaces of the shaft washer (WS) and seat washer (GS) were treated with zinc-phosphating. Subsequently, a solid lubricant solution (polytetrafluoroethylene [PTFE], MoS₂ and graphite) was sprayed onto the phosphated samples at concentrations of 1 , 2  and 3 g/L. The porous and adsorptive nature of the phosphating film was used to embed the solid lubricant particles into the film, thus forming a composite lubrication layer containing solid lubricants on the surface of the bearing steel.

The addition of solid lubricant materials has shown significant potential in reducing wear losses compared with phosphated samples without such additives. Increasing the amount of solid lubricant added can facilitate the formation of a transfer film, which further enhances the protective properties. However, it is important to note that excessive amounts of solid lubricant material can contribute to seizure, leading to increased wear losses of the cage and a higher average coefficient of friction (ACOF).By spraying a PTFE solution with a concentration of 2 g/L, the lowest ACOF and cage wear loss were achieved, resulting in reductions of 60.5% for the ACOF and 89.4% for the cage wear loss. Similarly, when spraying a graphite solution with a concentration of 3 g/L, the lowest wear losses for GS and WS were observed, with reductions of 51.7% for GS wear loss and 38.9% for WS wear loss.

The combination of the phosphating film and solid lubricants aims to achieve lubrication and wear reduction, providing a new approach to wear-resistant technology for TCRBs.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2023-0231/

The purpose of this paper is to reveal the friction and wear performance of grooves textured cylindrical roller thrust bearings with different groove dimensions under starved lubrication.

The groove dimensions include: width of grooves (WOG, 50 µm, 100 µm and 150 µm), depth of grooves (DPOG, 7 µm, 11 µm and 15 µm) as well as groove deflection angle (GDA, 45°). A fiber laser marking system was used to prepare groove patterns on the raceways of shaft washers. The friction and wear properties of grooves textured bearings were researched through a vertical universal wear test rig using a customized roller bearing tribo-pair under starved lubrication. Static finite element analyses were conducted to reveal their surface stresses. Through the comprehensive comparison and analyses, the influence mechanism of grooves on the tribological behavior of cylindrical roller thrust bearings was proposed and discussed.

When grooves textured bearings run under starved lubrication, their average coefficients of friction (COFs) and wear losses are all significantly reduced and much lower than those of smooth group. The influence of DPOG on the COF curves is significant, while the influence of WOG on the COF curves is a little weak. The influence of groove dimensions on the surface stresses of grooves textured bearings is weak, whether the WOG or DPOG. In this work, when the WOG is 100 µm and the DPOG is 15 µm, its average COF and wear loss are both the lowest, 0.0066 and 0.61 mg, respectively. Compared with the data of smooth group, its friction coefficient is reduced by 75.3% and its mass loss is reduced by 95.8%, showing a significant improvement in this condition.

This work can provide a valuable reference for the raceway design and reliability optimization of rolling element bearings.

The purpose of this paper is to study the influence of dimple textures on the friction and wear properties of tapered roller bearings (TRBs) with many pattern parameters, e.g. diameter, depth and area density under starved lubrication.

The pattern parameters include the dimple diameter (D; 60, 100 and 200 µm), dimple depth (H; 5, 10 and 20 µm) and area density (S; 6%, 12% and 24%). Dimples were fabricated on the outer ring (OR) of TRBs using a laser marking machine. The tribological properties of dimple-textured TRBs under starved lubrication were studied on a vertical universal friction wear tester with special friction pairs. The effect mechanisms of dimple textures on the tribological properties of TRBs are presented and summarized through experiments and discussions.

When dimple-textured TRBs revolve under starved lubrication, the average coefficients of friction (ACOF) and wear losses are markedly lower than those of non-textured bearings. S has the greatest influence on the COF curve. When D is 100 µm and S is 24%, the ACOF and wear losses are both lowest, i.e. 0.00426 and 0.51 mg, respectively. Under the same test conditions, compared with the non-textured group, its COF and wear loss decreased by 35.6% and 62.5%, respectively.

This work provides a useful reference for the research on the raceways of textured TRBs.

This study aims to investigate the effect of compound pit textures on the tribological properties of thrust cylindrical roller bearings (TCRBs) using several parameters, such as compound type, pit diameter, pit depth and pit area density.

The surface texture parameters of the shaft washer (WS) raceway include pit diameter (D; 100, 300 and 500 µm), pit depth (H; 10 and 20 µm) and pit area density (S; 10%, 13% and 18%). Pits were produced on the WS of the TCRBs using laser marking equipment. The friction and wear performances of compound pit-textured TCRBs under starved lubrication conditions are studied using a friction and wear test rig. The influence mechanisms of the compound pit texture on the friction and wear properties of TCRBs are discussed through real tests and discussions.

Compared with nontextured bearings, the average coefficient of friction (ACOFs) and wear loss of TCRBs with single/compound pit textures are reduced when rotating under starved lubrication. D has the greatest effect on the COFs curve. When D = 300 µm, H = 10 µm and S = 10%, the ACOF and wear loss are the lowest, that is, 0.0207 and 3.38 mg, respectively. Under the same lubrication conditions, compared with the nontextured bearing group, the COF and wear loss are reduced by 41.4 and 59.6%, respectively.

This study provides a useful reference for the raceways of textured TCRBs.

The purpose of this paper is to report the tribological behavior of dimples textured rolling element bearings (REBs) under variable load and starved lubrication.

The pattern parameters include line-diameter of dimples (200 µm, 250 µm, 300 µm), depth of dimples (10 µm, 20 µm, 30 µm). Dimple patterns were prepared on the raceways of the shaft washers of cylindrical roller thrust bearings (CRTBs). A vertical wear test rig was used to obtain their coefficients of friction (COFs) under stepped load (1200–6000 N, with a manually increase of 1200 N every 3600 s) and starved lubrication. The wear losses and worn surfaces were characterized. The tribological performance between stepped load and fixed load (4000 N) was compared. The influence mechanism of dimples on the friction and wear properties of CRTBs under stepped load and starved lubrication was also discussed.

Compared with the data of smooth ones, the average COFs of the dimples textured bearings are almost all reduced under stepped load and starved lubrication, while their mass losses almost all get higher. The depth−diameter ratio and the effective volume coefficient of dimples are the important factors. In this work, compared with the smooth group, when the line-diameter of dimple is 250 µm and the depth is 20 µm, i.e. the depth−diameter ratio is 0.08, its average COF is reduced by 46.8% and its mass loss is reduced by about 7%, showing wonderful friction-reducing effect and good wear resistance.

This work can provide a reference for the raceway design of REBs.