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This paper aims to investigate the effect of simulated body fluid (SBF) on biodegradation and tribological properties of ultrahigh molecular weight polyethylene (UHMWPE) and UHMWPE stabilized with α-tocopherol.

The samples of UHMWPE and UHMWPE stabilized with α-tocopherol were prepared by a hot-pressing method, and then immersed in SBF for one year. Tribological test was performed on a UMT-2 tribometer.

The crystallinity and tribological properties increased slightly after UHMWPE stabilized with α-tocopherol, whereas the O/C ration decreased slightly. The crystallinity and O/C ratio increased after all samples immersed in SBF for one year. This resulted in the deterioration of tribological properties and the wear mechanism change. The tribological properties change was smaller in UHMWPE stabilized with α-tocopherol than that in UHMWPE, because the oxidation resistance of UHMWPE was increased by α-tocopherol.

The results of the experimental studies demonstrated and compared the biodegradation behavior and tribological properties of UHMWPE, UHMWPE stabilized with α-tocopherol, and after they immersed in SBF for one year.

Wireless network localization technology is very popular in recent years and has attracted worldwide attention. The purpose of this paper is to improve the localization accuracy of ultra-wideband (UWB) with lower localization error taking into consideration the special real environment with the closed long and narrow space.

The principle of multidimensional scaling (MDS), particle swarm optimization (PSO) and Taylor series expansion algorithm (Taylor-D) were introduced. A novel positioning algorithm, MDS-PSO-Taylor was proposed to minimize the localization error. MDS-PSO algorithm provided a more accurate preliminary coordinate by applying the PSO algorithm so that the Taylor-D was used for further enhancing the localization accuracy.

Experimental results manifested that the proposed algorithm, providing small localization error value and higher positioning accuracy, can effectively reduce errors and achieve better performance in terms of the considerable improvement of localization accuracy.

The presented study with the real environment test attempts to demonstrate the proposed algorithm is hopeful to be applied to the underground environment for in the future.

Three types of pattern on the monocrystalline silicon surface were prepared by using laser surface processing equipment. The DLC film and Si-DLC film on the patterning surface were deposited by using PECVD-2D plasma chemical vapor deposition sets. The paper aims to discuss these issues.

The tribological properties of the films were investigated by using the UMT-2 micro friction and wear tester. The surface topography, composition, hardness and elastic modular of the films were determined by Raman spectrum, nano mechanics tester and three-dimensional topography instrument. The worn surface topographies of the surface patterning films were tested by scanning electron microscopy.

The results show that the patterning monocrystalline silicon substrate surface has good anti-friction property under low load. The patterning DLC film and Si-DLC film surface have very good anti-friction property under all the test loads. The reason of these results is that the surface patterning film not only reduces the real contact area of the friction pairs but also has low surface bonding force.

This paper prepared three kinds of microscopic patterns on the monocrystalline silicon surface by using laser surface processing equipment. And then deposited DLC film and Si-DLC film on the patterning surface. All kinds of surface patterning monocrystalline silicon had very good anti-friction property under low load. And all kinds of surface patterning nano-hard film had perfect anti-friction property under all test loads.

The objective of this paper is to determine fretting parameters of hoisting rope according to the hoisting parameters in coalmine and to explore the effect of contact load on fretting-fatigue behavior of steel wires.

Based on the mechanical model of hoisting rope in coalmine, the dynamic tension simulation of hoisting rope was performed. Static equations of hoisting rope under tension and torsion and theories of contact mechanics were applied to obtain fretting parameters. Fretting-fatigue tests of steel wires at different contact loads were conducted using a fretting-fatigue test rig. The fretting regime, normalized tangential force and fretting-fatigue life were studied. The morphologies of fretting contact scars and fracture surfaces were observed by scanning electron microscopy and optical microscopy to examine wear and failure mechanisms.

Dynamic tension changes from 0 to 30,900 N. In outer strand layer, contact loads between steel wires in certain wire layers are 60.5 and 38.3 N compared with 378 and 102.7 N between wire layers; relative displacements between wires are 62.5 and 113.2 μm, respectively. Mixed fretting regimes develop in all cases. Increasing contact load decreases the stabilized relative slip and normalized tangential force, reduces the fretting fatigue life, induces accelerated adhesive wear and fatigue wear and results in rougher fracture surface topographies. In all cases, fretting zone induces crack initiation; crack propagation and rupture zones present brittle cleavage and longitudinal splitting, respectively.

This paper presents the systemic study on determination of fretting parameters of hoisting rope according to the hoisting parameters in coalmine and the fretting-fatigue behavior of its internal steel wires. The results of fretting-fatigue tests show that the increase of contact load decreases the stabilized relative slip in mixed fretting regime and normalized tangential force, reduces the fretting fatigue life, induces accelerated adhesive wear and fatigue wear and results in rougher fracture surface topographies.

The authors warrant that the paper is original submission and is not being submitted to any other journal. And the research does not involve confidentiality, copyright infringement, leaks and other issues, all the responsibilities that the authors will take.

The purpose of this paper is to investigate the distribution and surface characteristic of transfer film of polyamide composites filled with ZnOw during traction rolling.

In this paper, the traction rolling tribological behavior of polyamide composites filled with ZnOw was studied with a twin-disc traction rolling tester. The topography of transfer film was observed with a three dimensional profiler. Meantime the thickness of transfer film was measured. The chemistry elements of transfer film were analyzed with EDS and XRD.

The results indicated that transfer film of composites patchily covered on the surface of counter disc, the amount of which increased with increasing cycles. The coverage and thickness of pure PA film increased against rolling cycles. However, the thickness of 15 wt.% ZnOw/PA film remained at 6 μm as the coverage rose against rolling cycles. Fe element was found in pure PA transfer film, which existed in Fe0 and FeO for chemical reaction between Fe and atmospheric oxygen. Transfer film of 15 wt.% ZnOw/PA composites included a little Zn and Fe element. Fe element existed as Fe0. Zn element existed as ZnO.

This paper presented the distribution and surface characteristic of transfer film during traction rolling.

This study aims to reconstruct the frictional vibration signal from noise and characterize the running-in process by frictional vibration.

There is a strong correlation between tangential frictional vibration and normal frictional vibration. On this basis, a new frictional vibration reconstruction method combining cross-correlation analysis with ensemble empirical mode decomposition (EEMD) was proposed. Moreover, the concept of information entropy of friction vibration is introduced to characterize the running-in process.

Compared with the wavelet packet method, the tangential friction vibration and the normal friction vibration reconstructed by the method presented in this paper have a stronger correlation. More importantly, during the running-in process, the information entropy of friction vibration gradually decreases until the equilibrium point is reached, which is the same as the changing trend of friction coefficient, indicating that the information entropy of friction vibration can be used to characterize the running-in process.

The study reveals that the application EEMD method is an appropriate approach to reconstruct frictional vibration and the information entropy of friction vibration represents the running-in process. Based on these results, a condition monitoring system can be established to automatically evaluate the running-in state of mechanical parts.

The EEMD method was applied to reconstruct the frictional vibration. Furthermore, the information entropy of friction vibration was used to analysis the running-in process.

This paper aims to improve shearer positioning accuracy. Shearer positioning using an inertial navigation system (INS) is a highly useful technology; however, positioning accuracy is seriously hindered by INS attitude error, particularly heading drift.

A shearer positioning model with double-INS based on extended Kalman filter was proposed. The constant distance between two INSs (INS 1 and INS 2) was selected as the observation vector. Allan variance was used to identify the noise type of the vertical-axis gyroscope, and the stochastic process of heading drift for two INSs was obtained and divided into incongruous drift and concurrent drift.

Simulation was then carried out to determine the optimal arrangement of the two INSs. For incongruous drift, the optimal arrangement satisfied the condition that the line connecting INS 1 and INS 2 was perpendicular to the shearer lateral axis (in the shearer coordinate frame) and parallel to the east-north plane (in the east-north-up coordinate frame). Under optimal arrangement, the positioning accuracy increased against the distance between INS 1 and INS 2. For concurrent drift, the double-INS positioning model had no effect. Under the circumstances, the number of INSs should be increased so that the uncertainty of INS drift was reflected as much as possible.

A new double-INS positioning model was proposed with the constant distance between the two INSs. The optimal arrangement for double-INS was obtained.

This paper aims to investigate the tribological benefits of a biomimetic teardrop surface texture inspired by snakeskin compared to conventional surface textures with the help of geometrical and flow parameters using computational fluid dynamics techniques.

The lubricant is assumed to be Newtonian, and the flow is laminar with constant viscosity and isothermal property. The governing equations, continuity and Navier–Stokes equation, are discretised by the finite volume method, and cavitation modelling is included. The discretisation for the momentum equations is carried out using the second-order difference method for the SIMPLEC algorithm of pressure–velocity coupling.

The results indicate that biomimetic teardrop surface texturing performs better than conventional shapes surface textures in improving tribological performance. Furthermore, the parallel texture orientation along with the flow generates a high-pressure distribution relative to other orientations. Surface texture area density also highly influences the load-carrying capacity, which is optimum at 29%. Zigzag pattern arrangement performs better compared to linear pattern arrangement of texturing.

The paper proposes that this unique biomimetic teardrop shape can give better tribological performance than conventional shapes.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2024-0053/