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Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fe-doped zirconia toughened alumina (Fe: ZTA) ceramic is a promising material for artificial joint implants because of high density, good mechanical properties and excellent wear resistance. To evaluate its use in biological implants, Fe: ZTA ceramics with different Fe contents (0–5 wt.%) were fabricated using the fast hot pressed sintering method, and the biocompatibility of Fe: ZTA ceramics and the biotoxicity of wear debris from Fe: ZTA were systematically studied. The additive Fe element mainly exists in the form of FeAl 2 O 4. The addition of Fe results in the increase of surface hydrophobicity and the decrease of surface energy and polar component, improving the protein absorption on Fe: ZTA surface. According to the culture results with osteoblasts and macrophages, Fe doping can increase the osteoblast activity and does not cause significant macrophage activation on the surface of Fe: ZTA ceramics. Particularly, the 1.5 wt.% Fe: ZTA ceramic can significantly improve the cytocompatibility of osteoblasts and reduce the inflammatory reaction. On this basis, 1.5 wt.% Fe: ZTA ceramic with the best biocompatibility was used to prepare the wear debris, and the biotoxicity of wear debris was further studied. The result confirms that wear debris of Fe: ZTA ceramic (50–1000 μ g/ml) does not cause the significant decrease in osteoblast activity and has no significant effect on the osteoblast morphology, without distinct cytotoxicity. The wear debris of Fe: ZTA (≤ 200 μ g/ml) will not cause significant inflammatory response. This study can provide guidance for the application of Fe: ZTA ceramic in biological implants. • Fe doping improves the protein adsorption on ZTA surface. • ZTA ceramics with Fe contents (0–5 wt.%) have good cell compatibility. • 1.5 wt% Fe: ZTA can improve osteoblasts cytocompatibility and reduce inflammatory reaction. • Wear debris of Fe: ZTA (50–200 μ g/mL) has no cytotoxicity and doesn't cause inflammation. [ABSTRACT FROM AUTHOR]

Copyright of China Rubber Industry is the property of Editorial Office of China Rubber Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the present paper, two austenitic wear-resistant steels, namely 110Mn13 and 0Cr17Ni10Mn5Mo2 steels, were cold-rolled to a same hardness level of ∼270 HV. Mechanical properties and wear resistance under various applied loads were tested. The deformed microstructure, worn surface morphologies and wear debris were discussed to analyze the wear resistance. Results showed that a higher density of deformation twins and dislocations were generated in the 0Cr17Ni10Mn5Mo2 steel to reach a same hardness level with the 110Mn13 steel. Consequently, the 0Cr17Ni10Mn5Mo2 steel obtained higher yield strength (736 MPa) but lower ultimate strength (896 MPa), elongation (30.5%) and strain hardening rate than the 110Mn13 steel when the impact absorption energies were at a similar level of ∼170 J. The weight loss of the 0Cr17Ni10Mn5Mo2 steel reduced by over 40% compared to that of the 110Mn13 steel under the selected wear conditions. With the cold-rolled microstructure, the worn surface of both the test steels produced nanocrystalline layers. The nanocrystalline layer thickness of the 0Cr17Ni10Mn5Mo2 steel was over 5 μm, far larger than that of the 110Mn13 steel. Meanwhile, with the wear debris containing Cr-oxide adhering to the worn surface, which could facilitate the self-lubricating effect, the 0Cr17Ni10Mn5Mo2 steel presented better wear resistance than the 110Mn13 steel.

Aim: Polymers and metals, such as polyethylene (PE) and cobalt chrome (CoCr), are common materials used in thumb-based joint implants, also known as CMC (Carpometacarpal) arthroplasty. The purpose of this review was to investigate the reported failure modes related to wear debris from these type of materials in CMC implants. The impact of wear debris on clinical outcomes of CMC implants was also examined. Potential adverse wear conditions and inflammatory particle characteristics were also considered. Method: A literature search was performed using PRISMA guidelines and 55 studies were reviewed including 49 cohort studies and 6 case studies. Of the 55 studies, 38/55 (69%) focused on metal-on-polyethylene devices, followed by metal-on-metal (35%), and metal-on-bone (4%). Results: The summarized data was used to determine the frequency of failure modes potentially related to wear debris from metals and/or polymers. The most commonly reported incidents potentially relating to debris were implant loosening (7.1%), osteolysis (1.2%) and metallosis (0.6%). Interestingly the reported mechanisms behind osteolysis and loosening greatly varied. Inflammatory reactions, while rare, were generally attributed to metallic debris from metal-on-metal devices. Mechanisms of adverse wear conditions included implant malpositioning, over-tensioning, high loading for active patients, third-body debris, and polyethylene wear-through. No specific examination of debris particle characterization was found, pointing to a gap in the literature. Conclusion: This review underscores the types of failure modes associated with wear debris in CMC implants. It was found that failure rates and adverse wear conditions of CMC implants of any design are low and the exact relationship between wear debris and implant incidences, such as osteolysis and loosening remains uncertain. The authors note that further research and specific characterization is required to understand the relationship between debris and implant failure. [ABSTRACT FROM AUTHOR]

Detailed characteristics wear particles formed in various brake pads were done. Our study was focused on identification structure and chemical composition of powder particles released by brake abrasion. The experimental studies were carried out using Mössbauer spectroscopy, X-ray powder diffraction, scanning electron microscopy and magnetic measurements. Structure and chemical composition of the original brake pads and disc samples were compared with the results obtained for wear particles. The chemical and phase composition of wear particles is in large part similar to composition of the original brake pads. Wear particles contained mainly various types of iron oxides, iron and iron carbon metallic particles. The part of the wear particles showed paramagnetic behaviour at room temperature. The sample with fully paramagnetic wear particles behaviour was subjected low temperature Mössbauer and magnetic measurements. The results indicate transition interval corresponding to magnetically ordered states—ferro/antiferromagnetic. [ABSTRACT FROM AUTHOR]

Most gears fail because of wear caused by rubbing, metal to metal contact, contamination, or breakdown of lubrication. Because of this, figuring out how to find and sort wear debris particles is an important area of research for both predictive and proactive maintenance. By putting these wear particles into different categories like spherical, cutting, fatigue, sliding and rubbing, it would be possible to identify the wear modes present in the gearbox and predict the nature of failure and condition of the system. The present research aims to automate the detection and classification process using the Convolutional Neural Network (CNN) integrated with Cascade classifier. CNN automatically extracts different suitable features from images by applying multiple filters on it and also reduces the complexity of image processing whereas the Cascade classifier is used to detect the particles by differentiating between positive and negative images by applying the Haar-like features into it. The objective of the research work is to provide a most efficient and accurate detection and classification of wear debris particles using a trained cascade classifier integrated with a customized lightweight CNN model named as Wear Particle Classifier Net (WPCnet).

The objective of this paper is to study the parameters that affect the remaining useful life of lubricant (RULL). Fourier‐transform infrared spectroscopy (FTIR) of gear oil is used to observe the contamination in the oil. Coefficient of friction (COF) has been found out using pin on disc tribometer using gear oil, and simultaneously, wear debris has been collected. Particles distribution and elemental analysis of wear debris were observed by emission scanning electron microscopy (FESEM) Field with energy dispersive x‐ray (EDX) respectively. Oxidation, sulfation, soot and water content in lubricant increase with time and decrease the RULL. ANOVA is applied to find out the most influential parameter for wear debris and found a load on gears is the dominating factor for wear. This method is the potential to monitor the root causes of contamination and change in lubricant properties and may help to detect the other early signs of failure. [ABSTRACT FROM AUTHOR]

The polyetheretherketone (PEEK)-highly cross-linked polyethylene (XLPE), all-polymer knee prosthesis has excellent prospects for replacing the traditional metal/ceramic-polyethylene joint prosthesis, improving the service life of the joint prosthesis and the quality of patients' life. The long-term wear mechanism of PEEK-XLPE knee joint prosthesis is comprehensively evaluated from wear amount, wear morphology, and wear debris compared to that of CoCrMo-XLPE joint prosthesis. After 5 million cycles of in vitro wear, the wear loss of XLPE in PEEK-XLPE (30.9±3.2 mg) is lower than that of XLPE in CoCrMo-XLPE (32.1±3.1 mg). Compared to the XLPE in CoCrMo-XLPE, the plastic deformation of XLPE in PEEK-XLPE is more severe in the early stage, and the adhesive peeling and adhesion are lighter in the later stage. The size distribution of XLPE wear debris in PEEK-XLPE is relatively dispersed, which in CoCrMo-XLPE is relatively concentrated. Wear debris is mainly flake and block debris, and the wear mechanism of XLPE was abrasive wear. The wear volume per unit area of PEEK femoral condyle (10.45×105 µm3/mm2) is higher than that of CoCrMo (8.32×105 µm3/mm2). The PEEK surface is mainly furrows and adhesions, while the CoCrMo surface is mainly furrows and corrosion spots. The PEEK wear debris is mainly in flakes and blocks, and the CoCrMo wear debris is mainly in the shape of rods and blocks. The wear mechanism of PEEK is abrasive wear and adhesion, and that of CoCrMo is abrasive wear and corrosion. [ABSTRACT FROM AUTHOR]

Almost all of the wear debris generated during the operation of the machine is suspended in the circulating lubricating oil. The analysis of the wear debris in the lubricating oil can effectively monitor the wear state of the machine and provide early warning of failures. An overview on inductive sensors for measuring wear debris in lubrication is introduced. To begin with, the significance of analyzing the wear debris in lubricating oil is explained and the working principle of the inductive wear sensors is illustrated. Furthermore, the development of inductive wear sensors and the key limitations are summarized. Finally, some rest factors affecting the sensor and the processing method of the induction signal aliasing are discussed, and the future development trend is prospected. It is pointed out that developing high sensitivity wear debris inductive sensors, increasing sensor throughput, and solving the problem of aliasing of detection signals are the following issues that should be further studied in the future. [ABSTRACT FROM AUTHOR]

Little is known about retrieved zirconia platelet toughened alumina (ZPTA) wear particles from ceramic-on-ceramic (COC) total hip arthroplasty. Our objectives were to evaluate clinically retrieved wear particles from explanted periprosthetic hip tissues and to analyze the characteristics of in vitro-generated ZPTA wear particles. Periprosthetic tissue and explants were received for 3 patients who underwent a total hip replacement of ZPTA COC head and liner. Wear particles were isolated and characterized via scanning electron microscopy and energy dispersive spectroscopy. The ZPTA and control (highly cross-linked polyethylene and cobalt chromium alloy) were then generated in vitro using a hip simulator and pin-on-disc testing, respectively. Particles were assessed in accordance with American Society for Testing and Materials F1877. Minimal ceramic particles were identified in the retrieved tissue, consistent with the retrieved components demonstrating minimal abrasive wear with material transfer. Average particle diameter from in vitro studies was 292 nm for ZPTA, 190 nm for highly cross-linked polyethylene, and 201 nm for cobalt chromium alloy. The minimal number of in vivo ZPTA wear particles observed is consistent with the successful tribological history of COC total hip arthroplasties. Due to the relatively few ceramic particles located in the retrieved tissue, in part due to implantation times of 3 to 6 years, a statistical comparison was unable to be made between the in vivo particles and the in vitro-generated ZPTA particles. However, the study provided further insight into the size and morphological characteristics of ZPTA particles generated from clinically relevant in vitro test setups. [ABSTRACT FROM AUTHOR]

Abstract The polyetheretherketone (PEEK)-highly cross-linked polyethylene (XLPE), all-polymer knee prosthesis has excellent prospects for replacing the traditional metal/ceramic-polyethylene joint prosthesis, improving the service life of the joint prosthesis and the quality of patients’ life. The long-term wear mechanism of PEEK-XLPE knee joint prosthesis is comprehensively evaluated from wear amount, wear morphology, and wear debris compared to that of CoCrMo-XLPE joint prosthesis. After 5 million cycles of in vitro wear, the wear loss of XLPE in PEEK-XLPE (30.9±3.2 mg) is lower than that of XLPE in CoCrMo-XLPE (32.1±3.1 mg). Compared to the XLPE in CoCrMo-XLPE, the plastic deformation of XLPE in PEEK-XLPE is more severe in the early stage, and the adhesive peeling and adhesion are lighter in the later stage. The size distribution of XLPE wear debris in PEEK-XLPE is relatively dispersed, which in CoCrMo-XLPE is relatively concentrated. Wear debris is mainly flake and block debris, and the wear mechanism of XLPE was abrasive wear. The wear volume per unit area of PEEK femoral condyle (10.45×105 µm3/mm2) is higher than that of CoCrMo (8.32×105 µm3/mm2). The PEEK surface is mainly furrows and adhesions, while the CoCrMo surface is mainly furrows and corrosion spots. The PEEK wear debris is mainly in flakes and blocks, and the CoCrMo wear debris is mainly in the shape of rods and blocks. The wear mechanism of PEEK is abrasive wear and adhesion, and that of CoCrMo is abrasive wear and corrosion.

Lubricated tribosystems such as main-shaft bearings in gas turbines have been successfully diagnosed by oil sampling for many years. In practice, the interpretation of wear debris analysis results can pose a challenge due to the intricate structure of power transmission systems and the varying degrees of sensitivity among test methods. In this work, oil samples acquired from the fleet of M601T turboprop engines were tested with optical emission spectrometry and analyzed with a correlative model. Customized alarm limits were determined for iron by binning aluminum and zinc concentration into four levels. Two-way analysis of variance (ANOVA) with interaction analysis and post hoc tests was carried out to study the impact of aluminum and zinc concentration on iron concentration. A strong correlation between iron and aluminum, as well as a weaker but still statistically significant correlation between iron and zinc, was observed. When the model was applied to evaluate a selected engine, deviations of iron concentration from the established limits indicated accelerated wear long before the occurrence of critical damage. Thanks to ANOVA, the assessment of engine health was based on a statistically proven correlation between the values of the dependent variable and the classifying factors. [ABSTRACT FROM AUTHOR]

Metals from spinal implants are released into surrounding tissues by various mechanisms. Metal ion release has been associated with clinical implant failure, osteolysis, and remote site accumulation with adverse events. Significant corrosion and associated metal ion release has been described with currently used spinal implant alloys. A novel metal alloy, Molybdenum-47.5Rhenium alloy (MoRe®), was approved for use in medical implants in 2019 by the FDA. To evaluate the metal ion release profile of MoRe alloy after immersion in both a stable physiologic, as well as in an inflammatory environment. In vitro study. The ion release profile of the MoRe alloy was comprehensively evaluated in-vitro after prolonged immersion in physiologic and inflammatory environments. Ion concentration analyses were then conducted using inductively coupled plasma-mass spectrometry (ICP-MS) methods. Comparative testing of titanium (Ti-6Al-4V) and cobalt chromium (Co-28Cr-6Mo) was also performed. Under baseline physiologic conditions, the MoRe alloy demonstrates very low molybdenum and rhenium ion release rates throughout the 30-day test period. During the first time interval (day 0–1), low levels of molybdenum and rhenium ions are detected (<0.3 μg/cm2 day) followed by a rapid reduction in the ion release rates to <0.05 μg/cm2 day during the second time interval (days 1–3) followed by a further reduction to very low steady-state rates <0.01 μg/cm2 day during the third time interval (days 3–7), which were maintained through 30 days. In the inflammatory condition (H 2 O 2 solution), there was a transient increase in the release of molybdenum and rhenium ions, followed by a return to baseline ion release rates (days 2–4), with a further reduction to low steady-state rates of ∼0.01 μg/cm2 day (days 4–8). The measured molybdenum and rhenium ion release rates in both steady state (<0.01 μg/cm2 day), and inflammatory environments (0.01 μg/cm2 day) were far below the established FDA-permitted daily exposure (PDE) of 1,900 μg/cm2 day for molybdenum and 4,400 μg/cm2 day for rhenium. In contrast, titanium and cobalt chromium approached or exceeded their established PDE values in an inflammatory environment. The novel biomaterial MoRe demonstrated a lower metal ion release profile in both a physiologic and inflammatory environment and was well below the established PDE. Comparative testing of the cobalt-chromium and titanium alloys found higher levels of ion release in the inflammatory environment that exceeded the PDE for cobalt and vanadium. [ABSTRACT FROM AUTHOR]

The phenomena associated with dry sliding wear of Mg-Ti3AlC2 composites have been investigated under a range of applied load, sliding velocity, and distance. Ti3AlC2 reinforcement of 20-40 vol.% was chosen to see the dependency of tribological responses such as coefficient of friction (CoF) and specific wear rate (SWR). Wear maps were also constructed to investigate variations in CoF and SWR with the aforementioned test variables. Our observation from those responses showed a marked decrease in CoF and SWR with an increase in load and speed. This phenomenon elucidates the ability of this composite to repair the worn-out surface. Compositional aspects of the tribo-film formed in the contact area showed the presence of mixed oxides enriched in Ti over Mg. [ABSTRACT FROM AUTHOR]

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Most gears fail because of wear caused by rubbing, metal to metal contact, contamination, or breakdown of lubrication. Because of this, figuring out how to find and sort wear debris particles is an important area of research for both predictive and proactive maintenance. By putting these wear particles into different categories like spherical, cutting, fatigue, sliding and rubbing, it would be possible to identify the wear modes present in the gearbox and predict the nature of failure and condition of the system. The present research aims to automate the detection and classification process using the Convolutional Neural Network (CNN) integrated with Cascade classifier. CNN automatically extracts different suitable features from images by applying multiple filters on it and also reduces the complexity of image processing whereas the Cascade classifier is used to detect the particles by differentiating between positive and negative images by applying the Haar-like features into it. The objective of the research work is to provide a most efficient and accurate detection and classification of wear debris particles using a trained cascade classifier integrated with a customized lightweight CNN model named as Wear Particle Classifier Net (WPCnet). [ABSTRACT FROM AUTHOR]

Aseptic loosening is the main reason for arthroplasty failure. The wear particles generated at the tribological bearings are thought to induce an inflammatory tissue response, leading to bone loss and the subsequent loosening of the implant. Different wear particles have been shown to activate the inflammasome, thereby contributing to an inflammatory milieu in the direct vicinity of the implant. The aim of this study was to investigate whether the NLRP3 inflammasome is activated by different metal particles in vitro and in vivo. Three different cell lines representing periprosthetic cell subsets (MM6, MG63 and Jurkat) were incubated with different amounts of TiAlV or CoNiCrMo particles. The activation of the NLRP3 inflammasome was determined through the detection of the caspase 1 cleavage product p20 in a Western blot. The formation of the inflammasome was also investigated in vivo using immunohistological staining for ASC in primary synovial tissues as well as tissues containing TiAlV and CoCrMo particles and in vitro after the stimulation of the cells. The results show that the CoCrMo particles induced ASC more markedly, as a readout for inflammasome formation in vivo, compared to TiAlV particular wear. The CoNiCrMo particles also induced ASC-speck formation in all the tested cell lines, which was not induced by the TiAlV particles. The Western blot shows that NRLP3 inflammasome activation, measured through caspase 1 cleavage, was increased only by the CoNiCrMo particles in the MG63 cells. We conclude from our data that the activation of the inflammasome is mainly driven by CoNiCrMo particles and less by TiAlV particles, indicating that different inflammatory pathways are activated by the different alloys. [ABSTRACT FROM AUTHOR]

Aseptic loosening and osteolysis continue to be a short- to mid-term problem for total ankle replacement (TAR) devices. The production of wear particles may contribute to poor performance, but their characteristics are not well understood. This study aimed to determine the chemical composition, size and morphology of wear particles surrounding failed TARs. A recently developed wear particle isolation method capable of isolating both high- and low-density materials was applied to 20 retrieved periprosthetic tissue samples from 15 failed TARs of three different brands. Isolated particles were imaged using ultra-high-resolution imaging and characterised manually to determine their chemical composition, size, and morphology. Six different materials were identified, which included: UHMWPE, calcium phosphate (CaP), cobalt chromium alloy (CoCr), commercially pure titanium, titanium alloy and stainless steel. Eighteen of the 20 samples contained three or more different wear particle material types. In addition to sub-micron UHMWPE particles, which were present in all samples, elongated micron-sized shards of CaP and flakes of CoCr were commonly isolated from tissues surrounding AES TARs. The mixed particles identified in this study demonstrate the existence of a complex periprosthetic environment surrounding TAR devices. The presence of such particles suggests that early failure of devices may be due in part to the multifaceted biological cascade that ensues after particle release. This study could be used to support the validation of clinically-relevant wear simulator testing, pre-clinical assessment of fixation wear and biological response studies to improve the performance of next generation ankle replacement devices. Total ankle replacement devices do not perform as well as total hip and knee replacements, which is in part due to the relatively poor scientific understanding of how they fail. The excessive production of certain types of wear debris is known to contribute to joint replacement failure. This is the first study to successfully isolate and characterise high- and low-density wear particles from tissues collected from patients with a failed total ankle replacement. This article includes the chemical composition and characteristics of the wear debris generated by ankle devices, all of which may affect their performance. This research provides clinically relevant reference values and images to support the development of pre-clinical testing for future total ankle replacement designs. [Display omitted] [ABSTRACT FROM AUTHOR]

Copyright of Die Orthopädie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Particulate and soluble debris are generated by mechanical and non-mechanical degradation of implanted medical devices. Debris containing cobalt and chromium (CoCr) is known to cause adverse biological reactions. Implant-related complications are often diagnosed using radiography, which results in more frequent patient exposure to ionizing radiation. The aim of this study was to evaluate the potential for increased toxicity due to combined radiation and CoCr exposure. This was investigated using a controlled in vitro model consisting of commercially available CoCr debris that was generated from components of hip replacements and human cell lines relevant to the joint environment: endothelial HMEC-1 and synovial SW982. Particle sizes and shapes were heterogenous. Cells tended to internalize smaller particles, as observed by electron microscopy. Indicators of toxicity were measured after short (24 h after radiation) or extended (12–14 d after radiation) exposure timelines. In the short-term, CoCr reduced cell viability, increased apoptosis, and increased oxidative stress. The effects of radiation were not apparent until the timeline was extended. CoCr and radiation reduced cell survival, with both additive and synergistic effects. Mechanisms for reduced survival included rapid cell death caused by CoCr and senescence caused by radiation. In conclusion, results showed combined toxicological effects of CoCr and radiation at the doses and timelines used for this in vitro model. These observations warrant further investigation using other experimental models to determine translational impact. [ABSTRACT FROM AUTHOR]

Aiming at the problems that electrical connectors reducing contact performance by fretting wear in vibration environments, an ultrasonic testing method was used to monitor the characteristic values of wear debris between electrical connector contacts during fretting wear, and to study the wear degree of contacts under different vibration conditions and the degradation law of contact performance. The results show that the vibration frequency, vibration acceleration, and fretting times have positive cumulative effects on the debris accumulation and contact resistance fluctuation. When the electrical connector vibrates axially, the debris accumulation effectiveness is the most obvious. The contact resistance and the total amount of wear debris characteristic values show a very high correlation under high vibration frequency and acceleration. The average absolute errors of SSA-BP performance degradation model are less than 5% based on the wear debris characteristic values. [ABSTRACT FROM AUTHOR]

The A359-SiCp/Fe interpenetrating phase composites reinforced with three-dimensional network structure iron foam and 20 wt. % SiC particles were fabricated after the infiltration technique by using the newly developed vacuum assisted infiltration procedures. The dry-sliding tribological behavior of A359-SiCp/Fe composites was investigated using the HT-1000 ball-on-disc type high temperature tribometer. The samples were subjected to a variety of temperatures and applied loads to investigate the influence on the wear rate and friction coefficient. In this study, SEM was used to analyses the wear microscopic morphology of A359-SiCp/Fe composites reinforced by iron foam. The wear longitudinal section and the morphology of the wear debris were analyzed by EDS and determined to explore the high-temperature wear mechanism under different temperatures and loads. Hardness analysis from the outer periphery to the core revealed an improvement in hardness. The hardness distribution of the wear longitudinal section is different at different temperatures. The formation of a high-hardness mechanical mixed layer with a different thickness on the wear surface can effectively reduce the wear rate. Microstructural investigations demonstrated that the change in wear debris shape with increasing temperature is mostly related to the change in wear mechanism. Abrasive wear and oxidation wear are the main wear mechanisms. With an increase in temperature and plastic deformation, delamination and adhesion are the predominant wear mechanisms, accompanied by the additional oxidative wear. [ABSTRACT FROM AUTHOR]

Periprosthetic osteolysis remains a leading complication of total hip and knee arthroplasty, often resulting in aseptic loosening of the implant and necessitating revision surgery. Wear-induced particulate debris is the main cause initiating this destructive process. The purpose of this article is to review recent advances in understanding of how wear debris causes osteolysis, and emergent strategies for the avoidance and treatment of this disease. A strong activator of the peri-implant innate immune this debris-induced inflammatory cascade is dictated by macrophage secretion of TNF-α, IL-1, IL-6, and IL-8, and PGE2, leading to peri-implant bone resorption through activation of osteoclasts and inhibition of osteoblasts through several mechanisms, including the RANK/RANKL/OPG pathway. Therapeutic agents against proinflammatory mediators, such as those targeting tumor necrosis factor (TNF), osteoclasts, and sclerostin, have shown promise in reducing peri-implant osteolysis in vitro and in vivo; however, radiographic changes and clinical diagnosis often lag considerably behind the initiation of osteolysis, making timely treatment difficult. Considerable efforts are underway to develop such diagnostic tools, therapies, and identify novel targets for therapeutic intervention. [ABSTRACT FROM AUTHOR]

Wire rope has different degrees of surface wear under long-distance transmission conditions, which leads to performance degradation and greatly threatens its safety and reliability in service. In this paper, friction and wear tests between the transmission wire rope and sheave under different sliding velocities (from 0.8 m/s to 1.6 m/s) were carried out using a homemade test rig. The material of the steel wires was low carbon steel, and pulley material was ASTM A36 steel plate. The sliding friction coefficient (COF), friction temperature rise, wear characteristic parameters and wear mechanisms of the wire rope were analyzed. Additionally, the effect of different wear on the fracture behavior of the wire rope was investigated by a breaking tensile test. The results show that the average COF in the relatively stable stage decreased from approximately 0.58 to 0.51 with the increase of sliding velocity. The temperature rise of the wire rope increased rapidly with an increase of sliding velocity, from approximately 52.7 °C to 116.2 °C. The maximum wear width was the smallest when the sliding velocity was 1.2 m/s (approximately 1.5 mm). The surface wear was characterized by spalling, furrowing and plastic deformation, which are strongly affected by the sliding velocity. The wear mechanisms of the wire rope were mainly adhesive wear and abrasive wear. Surface wear changes the fracture morphology of the wire rope and accelerates its fracture speed. [ABSTRACT FROM AUTHOR]

Submicron‐sized wear particles are generally accepted as a potential cause of aseptic loosening when produced in sufficient volumes. With the accelerating use of increasingly wear‐resistant biomaterials, identifying such particles and evaluating their biological response is becoming more challenging. Highly sensitive wear particle isolation methods have been developed but these methods cannot isolate the complete spectrum of particle types present in individual tissue samples. Two established techniques were modified to create one novel method to isolate both high‐ and low‐density materials from periprosthetic tissue samples. Ten total hip replacement and eight total knee replacement tissue samples were processed. All particle types were characterized using high resolution scanning electron microscopy. UHMWPE and a range of high‐density materials were isolated from all tissue samples, including: polymethylmethacrylate, zirconium dioxide, titanium alloy, cobalt chromium alloy and stainless steel. This feasibility study demonstrates the coexistence of mixed particle types in periprosthetic tissues and provides researchers with high‐resolution images of clinically relevant wear particles that could be used as a reference for future in vitro biological response studies. [ABSTRACT FROM AUTHOR]

Ferrography analysis is one of main means to identify wear state of mechanical equipment, and its key is the intelligent recognition of wear debris ferrographic images. Ferrographic image acquisition is a complex and time-consuming work, so the direct deep learning cannot been carried out for the small tested samples. A virtual ferrographic image dataset is prepared firstly and then two-level transfer learning scheme is proposed to improve the identification rate of the tested samples based on the deep learning model trained by the virtual samples. A combined network of YOLOv3 and DarkNet53 is constructed, and the application effect of model is improved by two-level transfer learning of virtual dataset to open dataset and then open dataset to tested dataset, and the model errors before and after twice transfer learning are analyzed. The average identification accuracy of the model in the validation dataset is 86.1%, which is 44.5% higher than that without two-level transfer learning, and the average recall reaches 95.8%. The experimental results prove the proposed method have a high identification rate for the tested ferrographic images of an actual gearbox. [ABSTRACT FROM AUTHOR]

The mechanism underlying induction of periprosthetic osteolysis by wear particles remains unclear. In this study, cultured MLO‐Y4 osteocytic cells were exposed to different concentrations of titanium (Ti) particles. The results showed that Ti particles increased expression of the osteocytic marker SOST/sclerostin in a dose‐dependent manner, accelerated apoptosis of MLO‐Y4 cells, increased the expression of IL‐6, TNF‐α and connexin 43. SOST silence alleviated the increase of MLO‐Y4 cells apoptosis, decreased the expression of IL‐6, TNF‐α and connexin 43 caused by Ti particles. The different co‐culture systems of MLO‐Y4 cells with MC3T3‐E1 osteoblastic cells were further used to observe the effects of osteocytic cells' changes induced by Ti particles on osteoblastic cells. MLO‐Y4 cells treated with Ti particles inhibited dramatically differentiation of MC3T3‐E1 cells mostly through direct cell‐to‐cell contact. SOST silence attenuated the inhibition effects of Ti‐induced MLO‐Y4 on MC3T3‐E1 osteoblastic differentiation, which ALP level and mineralization of MC3T3‐E1 cells increased and the expression of ALP, OCN and Runx2 increased compared to the Ti‐treated group. Taken together, Ti particles had negative effects on MLO‐Y4 cells and the impact of Ti particles on osteocytic cells was extensive, which may further inhibit osteoblastic differentiation mostly through intercellular contact directly. SOST/sclerostin plays an important role in the process of mutual cell interaction. These findings may help to understand the effect of osteocytes in wear particle‐induced osteolysis. [ABSTRACT FROM AUTHOR]

Diamond-like carbon (DLC) wear debris, which is often composed of different types of structures, is generated from DLC-modified artificial joints in the human body, and its biocompatibility evaluation is especially important to prevent wear-debris-induced implant failure. Here, RAW 264.7 macrophages (inflammatory-reaction assay) and primary mouse osteoblasts (osteoblastogenesis assay) were employed to investigate the toxicity of DLC wear particles (DWPs) by evaluation of cell viability and morphology, enzyme-linked immunosorbent assays, and quantitative reverse-transcription polymerase chain reaction (PCR). Relevant histopathological analysis of rat joints was also performed in vivo . We found that DWPs with a relatively high sp 2 /sp 3 ratio (graphite-phase tendency) manifested a higher cytotoxicity and significant inhibition of osteoblastogenesis. DWPs with a relatively low sp 2 /sp 3 ratio (diamond-phase tendency) showed good biocompatibility in vivo . The DWPs exhibiting a low sp2/sp3 ratio demonstrated reduced secretion of TNF-α and IL-6, along with increased secretion of TIMP-1, resulting in the downregulation of MMP-2 and MMP-9 and upregulation of interleukin-10 (IL-10), thereby attenuating the inflammatory response. Moreover, coculturing osteoblasts with DWPs exhibiting a low sp 2 /sp 3 ratio resulted in an elevated OPG/RANKL ratio and increased expression of OPG mRNA. Because of the absence of electrostatic repulsion, DWPs with a relatively low sp 2 /sp 3 ratio enhanced bovine serum albumin adsorption, which favored cellular activities. Cytotoxicity assessment of DWPs can help establish an evaluation system for particle-related joint disease and can facilitate the clinical application of DLC-coated prostheses.

Background: The objective of this study was to perform a polyethylene wear test on a non-mechanically linked total elbow arthroplasty implant using a clinically relevant in-vitro elbow wear test methodology that simulated ten years of use in the light to moderate activity of daily living range., Materials and Methods: The test protocol applied an 80° arc of ulnohumeral motion beginning at 30° shy of full extension and progressing to 110° of flexion. Force was applied at 7° to recreate a valgus load on the elbow. A variable joint load profile at a frequency of 0.5 Hz was employed. The implants were tested for 5 million cycles (Mc) in a bovine serum lubricant. Implant component failure was characterized and polyethylene wear was determined gravimetrically., Results: After 5 Mc the small polyethylene bushing wear rate was 0.56 mg/Mc. The medium size wear rate was 0.28 mg/Mc. Three large sizes were tested and the average wear rate was 0.39 ± 0.07 mg/Mc. No implant failure was identified., Conclusion: The test recreated an in vivo loading environment and measured polyethylene wear rates at specified cycle counts. The test demonstrated less wear than other joint replacements. Further clinical evaluation is necessary to determine if this translates into reduced complications of total elbow replacement associated with wear., (Copyright © 2024. Published by Elsevier Inc.)

Lubricated tribosystems such as main-shaft bearings in gas turbines have been successfully diagnosed by oil sampling for many years. In practice, the interpretation of wear debris analysis results can pose a challenge due to the intricate structure of power transmission systems and the varying degrees of sensitivity among test methods. In this work, oil samples acquired from the fleet of M601T turboprop engines were tested with optical emission spectrometry and analyzed with a correlative model. Customized alarm limits were determined for iron by binning aluminum and zinc concentration into four levels. Two-way analysis of variance (ANOVA) with interaction analysis and post hoc tests was carried out to study the impact of aluminum and zinc concentration on iron concentration. A strong correlation between iron and aluminum, as well as a weaker but still statistically significant correlation between iron and zinc, was observed. When the model was applied to evaluate a selected engine, deviations of iron concentration from the established limits indicated accelerated wear long before the occurrence of critical damage. Thanks to ANOVA, the assessment of engine health was based on a statistically proven correlation between the values of the dependent variable and the classifying factors.

Light-weight metal matrix composites, especially magnesium-based composites, have recently become more widespread for high-efficiency applications, including aerospace, automobile, defense, and telecommunication industries. The squeeze cast AZ91 base material (AZ91-BM) and its composites having 23 vol.% short carbon fibers were fabricated and investigated. The composite specimens were machined normal to the reinforced plane (Composite-N) and parallel to the reinforced plane (Composite-P). All the as-casted materials were subjected to different tests, such as hardness, compression, and wear testing, evaluating the mechanical properties. Dry wear tests were performed using a pin-on-disk machine at room temperature under different applied wear loads (1–5 N) and different sliding distances ( 0.4461 × 10 4 – 3.12 × 10 4 m). The microstructures and worn surfaces of the fabricated AZ91-BM and the two composite specimens were investigated using a scanning electron microscope (SEM) equipped with an energy dispersive spectroscopy (EDS) advanced analysis system. The wear debris was collected and investigated also under the SEM. The results showed significant improvement in hardness, compressive strength, and wear resistance of the composite specimens (Composite-N and Composite-P) over the AZ91-BM. The compressive strength and wear resistance are more fibers orientation sensitive than the hardness results. When the fiber orientation is parallel to the sliding direction (Composite-N), the weight loss is somewhat lower than that of the fiber orientation perpendicular to the sliding direction (Composite-P) at a constant wear load of 2 N and the sliding distances of 0.4461 × 10 4 , 1.34 × 10 4   , and 2.23 × 10 4 m. In contrast, the weight loss of Composite-P is lower than Composite-N, especially at the highest sliding distance of 3.12 × 10 4 m due to the continuous feeding of graphite lubricant film and the higher compressive strength. Plastic deformation, oxidation, and abrasive wear are the dominant wear mechanisms of AZ91-BM; in contrast, abrasive and delamination wear are mainly the wear mechanisms of the two composites under the applied testing conditions. [ABSTRACT FROM AUTHOR]

Inductance detection is an important method for detecting wear debris in ship lubricating oil. Presently, an LCR (inductance, resistance, capacitance) meter is generally used to detect wear debris by measuring the inductance change of the sensing coil. When ferromagnetic debris passes through the sensing coil, a pulse will appear in the inductance signal. Previous studies have shown that the amplitude of the inductance pulse decreases significantly with the increase in the particles' velocity. Therefore, it is difficult to detect ferromagnetic debris with a high flow velocity using an LCR meter. In this paper, a novel method, high-frequency voltage acquisition (HFVA), is proposed to detect ferromagnetic debris. Different from previous methods, the wear debris was detected directly by measuring the voltage change of the sensing coil, while the synchronized sampling method was utilized to ensure the higher-frequency acquisition of the sensor output signal. The experimental results show that when the velocity of particles increased from 6 mm/s to 62 mm/s, the amplitude of the signal pulse obtained by HFVA decreased by only 13%, which was much lower than the 85% obtained by utilizing the LCR method. [ABSTRACT FROM AUTHOR]

Nanoparticles as lubricant additives under a certain average diameter and concentration may reduce wear, friction and scuffing damage. However, atmospheric dust particles affect not only human health but also the efficiency of components, and even cause component failures. Therefore, the contact characteristics at interfaces with foreign particles require careful investigation. In this work, a 3-body microcontact mechanics concept is used to analyze the effects of wear debris and foreign particles on real contact area, contact mode, asperity deformation type and separation at interface. The results show that the relationship profile between dimensionless real contact area (At*) and dimensionless normal contact load (Ft*) is wedge-shaped in a 3-body contact interface. Using surface-to-surface 2-body contact area as upper bound and surface-to-particle 3-body contact as lower bound, the 3-body hybrid contact situation is in between upper and lower bounds. As the dimensionless normal contact load increases, At* increases gradually as well. The order of contact mode is p-s contact, hybrid contact and then s-s contact. If the 3-body contact interface is in hybrid contact mode, the decrease in the hardness and average third body diameter will cause the At* to increase significantly at the same Ft*. Conversely, the separation and real contact area ratio of plastic deformation decrease gradually. The turning point of contact area (TPCA) occurs when the contact mode is within hybrid contact mode and the ratio of average third body diameter to the composite equivalent surface RMS roughness is about 50–70% for foreign particles and wear debris. When the Ft* is slightly larger than Ftpca*, the third body and surface share the total interface load approximately equally which will help reduce the real contact pressure and plastic contact area to improve surface performance. [ABSTRACT FROM AUTHOR]

The cemented Spectron EF stem in combination with the cemented non‐crosslinked Reflection All‐Poly cup showed a high rate of mid‐term aseptic loosening. However, the failure mechanisms are not fully known. We assessed the inflammatory tissue reactions and wear particles in periprosthetic tissues, implant wear and blood metal ion levels in 28 patients with failed implants. Histological analysis showed a macrophage pre‐dominant pattern with randomly distributed lymphocytes, with various amounts of neutrophils and giant cells. The number of different cell types in the tissue samples from patients in the cup group and in the stem group was similar. Wear particles, mainly ZrO2, CoCrMo, and polyethylene particles of different sizes and shapes, were associated with macrophages/giant cells, and total particle load/mm2 was higher in cases of stem loosening. The Spectron EF stems were heavily worn, abraded, and polished. Stem abrasion correlated with metal ion concentrations in blood. The median polyethylene wear rate of the Reflection cups was 0.23 mm/year. The high proximal roughness of the Spectron EF stem resulted in excessive cement wear during loosening. The resulting inflammatory tissue responses to the degradation products both from the cup and the stem led to massive osteolysis and subsequent implant loosening. [ABSTRACT FROM AUTHOR]

Objectives: The aim of the present work was to comparatively investigate the generation and characteristics of fretting and sliding wear debris produced by CuNiAl against 42CrMo4. Methods: Tribological tests were conducted employing a self-developed tribometer. Most experimental conditions were set the same except for the amplitudes and number of cycles. Morphological, chemical, microstructural and dimensional features of the worn area and debris were investigated using optical microscope (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and a laser particle sizer. Outcomes: Not only wear scar profiles but also the wear debris color, distribution and generated amount under fretting and sliding wear modes were quite different, which can be attributed to the significant difference in wear mechanisms. Particle size analysis indicates that the fretting debris has a smaller size distribution range; the biggest detected fretting and sliding wear debris sizes were 141 μm and 355 μm, respectively. Both fretting and sliding debris are mainly composed of copper and its oxides, but the former shows a higher oxidation degree. [ABSTRACT FROM AUTHOR]

Sensors for detecting wear particles in fluid lubricants have been widely studied owing to their ability to diagnose mechanical machine conditions and to help in preventing mechanical failures caused by wear particles or contamination particles. The proposed novelty sensor was fabricated using photolithography to make the complementary split ring resonator (CSSR) on PCB and it utilized neodymium magnets at the center of the CSRR structure to attract ferrous wear particles. The proposed sensor was tested, and we found that it is highly sensitive and could detect 50 ppm of ferrous wear particles larger than $10 \mu \text{m}$ dissolved in mineral white oil ISO VG 15. The sensor of this article has a low-cost and can be used in different situations to measure the ferrous wear particles while monitoring the real-time mechanical equipment wear, as it can be easily integrated into them. The sensor offers good accuracy, and is insensitive to fluid transparency and bubble formation, unlike other sensors for detection of wear particles. Therefore, the proposed novelty sensor of this work is in line with Industry 4.0, which requires many low-cost sensors for continuous monitoring to apply predictive maintenance techniques for extending the lifespan of infrastructures. [ABSTRACT FROM AUTHOR]