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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.)

This study is aimed at empirically investigating the impact of oil and grease content of bilge water on Nigeria's Coastal environment. Literatures were reviewed and the study adopted an experimental research design. The researchers applied laboratory experimental analysis, physicochemical parameters of ship generated wastewater from vessels against the DPR standard was measured. The results of the analysis showed that the value of oil/Grease content of Bilge water is 72µg/L while the DPR limit value is 48 µg/L, however, the mean value of Oil/grease content of wastewater is 35.0 µg/L. Based on the findings, the researchers rejected hypothesis one and accepted hypothesis two, hence concluded that the value of oil/grease content of bilge water is significantly different from the mean DPR Limit. They also concluded that the mean value of oil/grease content of wastewater is not significantly different from the mean DPR Limit. Based on the result, the researchers recommended appropriate measures for the disposal of ship wastewater; better policy implementation and enforcement for strict compliance on bilge water disposal as well as adequate treatment of onboard wastewater. [ABSTRACT FROM AUTHOR]

To increase the anti-wear (AW) and anti-scuffing possibilities of commercially available lithium grease, this paper proposed enriching the original composition with functionalised carbon nanotubes (CNTs) at a concentration of 0.1% (w/w). The CNTs were modified by decorating them with nanoparticles of two metals with established tribological potential: copper and nickel. The AW and extreme-pressure properties were determined using the customised ISO-20623 test on a four-ball apparatus. The AW properties were determined using the standardised parameter MWSD (mean wear scar diameter) and the anti-scuffing properties using the last non-seizing load. The greases enriched with nanoadditives showed better AW properties compared to the reference grease at higher loads (1–1.2 kN). Particularly favourable results were observed for grease with the addition of Cu-decorated CNTs, for which the MWSD values were more than 50% lower than the reference. Optical microscopy, SEM and TEM microscopy with EDS analysis, and Raman spectroscopy were used to identify the wear mechanisms and characterise the role of nanoadditives in the lubrication process. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office 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.)

This paper focuses on the study of thickener behaviour in elastohydrodynamic contacts using fluorescence microscopy and optical interferometry. A standard Ball-on-disc configuration tribometer was used as well as a newly developed Ball-on-ring configuration tribometer mimicking the conditions in a 6314 deep groove ball bearing. Three types of custom-made greases were used with the same base oil and Coumarin 6 fluorescent dye on the thickener. These greases contained no additives and were of the lithium complex and alicyclic di-urea type. It was confirmed that the behaviour of the grease was directly influenced by both the structure and type of thickener, and the differences were successfully observed by fluorescence microscopy. The concentration of thickener was found to change due to the formation or breakdown of the deposited thickener layer on the track. At low speeds, the alicyclic di-urea forms a thickener layer on the track that is more pronounced than the lubricating film formed by the base oil alone. The thickener layer formation also occurs at higher speeds when fully flooded conditions are beneficial in building the layer. Experiments with a Ball-on-ring tribometer show that the natural replenishment of the real contact geometry is more effective than on a Ball-on-disc tribometer, but the formation of the thickener layer on the track is more limited than in a Ball-on-disc tribometer with artificial replenishment. At higher velocities, a smaller but stable layer is formed where the layer does not change much from a certain velocity. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office 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.)

Copyright of Bearing is the property of Bearing Editorial Office 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.)

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.)

This study is aimed at empirically investigating the impact of oil and grease content of bilge water on Nigeria’s Coastal environment. Literatures were reviewed and the study adopted an experimental research design. The researchers applied laboratory experimental analysis, physicochemical parameters of ship generated wastewater from vessels against the DPR standard was measured. The results of the analysis showed that the value of oil/Grease content of Bilge water is 72µg/L while the DPR limit value is 48 µg/L, however, the mean value of Oil/grease content of wastewater is 35.0 µg/L. Based on the findings, the researchers rejected hypothesis one and accepted hypothesis two, hence concluded that the value of oil/grease content of bilge water is significantly different from the mean DPR Limit. They also concluded that the mean value of oil/grease content of wastewater is not significantly different from the mean DPR Limit. Based on the result, the researchers recommended appropriate measures for the disposal of ship wastewater; better policy implementation and enforcement for strict compliance on bilge water disposal as well as adequate treatment of onboard wastewater.

This article explores the intersections between TikTok, musical theatre and youth cultures. Since its international debut in 2017, TikTok has become closely associated with teenagers and twenty-somethings who use the social media platform as a critical site to create, present and experience identities and generational culture at large. Musical theatre has been central to this cultural work. Teenage theatre makers, for example, use TikTok as a marketing tool that can be replicated by professional theatre companies and productions. I present an autoethnographic account of my work with high school students to market an all-school production of the musical Grease and use the experience to question the ways emerging digital platforms such as TikTok inform new, accessible ways of collaborating, experiencing, appreciating, conceptualizing and documenting musical theatre. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office 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.)

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.)

Wheel bearings play a crucial role in ensuring the smooth and reliable rotation of wheels in automotive applications. Grease is commonly used as a lubricant in wheel bearings. The physical properties of grease, such as viscosity, base oil type, and thickener composition, significantly influence the overall performance and longevity of wheel bearings. This study investigates the impact of grease's physical properties on wheel bearing friction torque and service life. To evaluate the effects of different grease formulations, a series of experiments were conducted using a four-ball tester, rheometer, and a custom-built test rig to measure bearing frictional torque and service life. Multiple greases with varying viscosity grades, base oil types (mineral oil, synthetic oil), and thickener compositions (lithium, diurea, and polyurea) were tested under controlled operating conditions. Friction torque measurements were obtained using a high-accuracy torque sensor, while service life was determined by monitoring the bearing life in actual endurance testing. The results indicated that grease physical properties directly affected wheel bearing friction torque and service life. Low to Medium-viscosity greases generally exhibited 35–40% lower friction torque due to enhanced lubrication film formation and reduced metal-to-metal contact however, excessively high viscosity resulted in 50–60% higher frictional torque and thereby increased energy consumption. Different base oil types showed varying friction reduction and service life level, with mineral oil in some cases showed lower frictional torque around 30–40% particularly at high temperature but with significant reduction in the service life. Furthermore, the thickener composition significantly influenced grease performance. Based on these findings, selecting the appropriate grease with optimal physical properties is crucial for minimizing friction torque and extending the service life of wheel bearings. [ABSTRACT FROM AUTHOR]

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office 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.)

Grease is used as a lubricant in a wide range of fields, including bearings, because it reduces friction, prevents harmful wear of components, protects against rust and corrosion, and acts as a seal to prevent the invasion of dirt and water. Although most of the research on grease has focused on the environment inside the bearing, there has been little research on the fundamental lubrication mechanism of grease. It is known that thickeners, which keep a complex three-dimensional structure in the grease, have a significant effect on the shear characteristics of grease, and it is assumed that this is due to the orientation of the thickener structure in the shear direction. In this study, the apparent viscosity of grease in a micro-order gap was measured using our original viscometer and compared with the apparent viscosity measured with a submillimeter-order gap rheometer because grease may show different rheological properties compared to conventional measurements. In addition, the dynamic response of viscous resistance that appeared when each grease was subjected to a change in the shear force was quantitatively evaluated using relaxation time. As a result, the apparent viscosity remarkably decreased in a micro-order gap compared to a submillimeter gap, and two types of shear thinning mechanisms were proposed based on the orientation of the thickener: one caused by the narrow gap and the other by the shear force. In addition, the behavior of viscous resistance due to changes in the shear force depended on the type of thickener. It was also confirmed that the relaxation time of each grease correlates with its oil film-forming ability and the entanglement level of the thickener's structure. Furthermore, the mechanism of the dynamic response was proposed based on the reorientation of thickeners. [ABSTRACT FROM AUTHOR]

Energy-saving technology has become increasingly significant as one of the carbon-neutral options for suppressing recent global warming. Greaselubricated bearings have been used in various automotive and industrial machinery, requiring low torque and long service life for energy-saving performance, which is greatly influenced by grease fluidity. A numerical approach for understanding grease fluidity is very complex since grease is a non-Newtonian fluid with thixotropic properties. Visualization technique is one of the helpful methods to understand the complex grease fluidity and apply it to practical use. This paper describes state-of-the-art visualization techniques, such as fluorescence method, particle imaging velocimetry, infrared spectroscopy, X-rays, and neutron beams. [ABSTRACT FROM AUTHOR]

AbstractIn our research described here gold-phase molybdenum disulfide (1T-MoS2)/graphite-phase carbon nitride (g-C3N4) composites were prepared by a simple solvent-thermal method to investigate their synergistic lubrication in poly-α-olefin lithium grease by the four-sphere mode. The growth of 1T-MoS2 on g-C3N4 nanosheets was demonstrated by scanning electron microscopy (SEM), X-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FTIR). Tribological tests showed that the best tribological performance of the poly-α-olefin grease was achieved when the concentration of 1T-MoS2/g-C3N4 was 3 wt%; the coefficient of friction and the diameter of the abrasion marks were reduced by 37.7% and 51.2%, respectively, compared with the pure grease. Investigating the wear marks by field emission scanning electron microscopy (FE-SEM) and elemental mapping analysis, it was found that the coupling between the liquid lubrication film and the solid friction film and the synergistic effect between 1T-MoS2 and g-C3N4 were important factors to improve the tribological performance of the poly-α-olefin grease. We, therefore, note this study is expected to promote the development of new, high-performance greases. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office 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.)

The infrared (IR) absorption spectral data of 63 kinds of lubricating greases containing six different types of thickeners were obtained using the IR spectroscopy. The Kohonen neural network algorithm was used to identify the type of the lubricating grease. The results show that this machine learning method can effectively eliminate the interference fringes in the IR spectrum, and complete the feature selection and dimensionality reduction of the high-dimensional spectral data. The 63 kinds of greases exhibit spatial clustering under certain IR spectrum recognition spectral bands, which are linked to characteristic peaks of lubricating greases and improve the recognition accuracy of these greases. The model achieved recognition accuracy of 100.00%, 96.08%, 94.87%, 100.00%, and 87.50% for polyurea grease, calcium sulfonate composite grease, aluminum (Al)-based grease, bentonite grease, and lithium-based grease, respectively. Based on the different IR absorption spectrum bands produced by each kind of lubricating grease, the three-dimensional spatial distribution map of the lubricating grease drawn also verifies the accuracy of classification while recognizing the accuracy. This paper demonstrates fast recognition speed and high accuracy, proving that the Kohonen neural network algorithm has an efficient recognition ability for identifying the types of the lubricating grease. [ABSTRACT FROM AUTHOR]

Increasing interest in utilizing bio-lubricants has been sparked by pollution caused by the mineral oil-based lubricants and their depletion. This study aimed to assess the effectiveness of Jatropha oil based grease as a basis and sodium thickener as an additive. The grease's lubricating abilities were tested using the ASTM 2266 four ball test and molybdenum disulphide as an additive. According to the findings, adding molybdenum disulphide particles decreased wear and the coefficient of friction, with the latter falling by 69% when compared to virgin Jatropha grease. Given that Jatropha grease passed the four ball test, a simulation of real-world conditions, this indicates that it is a reliable lubricant. Wear examinations were performed on steel balls using an optical microscope and scanning electron microscopy, and the results were consistent. It was found that addition of 0.25% MoS2 to virgin Jatropha grease reduced coefficient of friction to 0.12 (69%) from 0.39. Similarly wear scar diameter reduced from 800.583 µ to 788.44 µ in presence of 0.25% MoS2 blended grease. The study concludes that the grease prepared could an alternative to grease made from mineral oils. The focus on adopting Jatropha grease as a more sustainable and bio-degradable option can preserve the environment.

To increase the anti-wear (AW) and anti-scuffing possibilities of commercially available lithium grease, this paper proposed enriching the original composition with functionalised carbon nanotubes (CNTs) at a concentration of 0.1% (w/w). The CNTs were modified by decorating them with nanoparticles of two metals with established tribological potential: copper and nickel. The AW and extreme-pressure properties were determined using the customised ISO-20623 test on a four-ball apparatus. The AW properties were determined using the standardised parameter MWSD (mean wear scar diameter) and the anti-scuffing properties using the last non-seizing load. The greases enriched with nanoadditives showed better AW properties compared to the reference grease at higher loads (1–1.2 kN). Particularly favourable results were observed for grease with the addition of Cu-decorated CNTs, for which the MWSD values were more than 50% lower than the reference. Optical microscopy, SEM and TEM microscopy with EDS analysis, and Raman spectroscopy were used to identify the wear mechanisms and characterise the role of nanoadditives in the lubrication process.

Copyright of Bearing is the property of Bearing Editorial Office 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.)

The present study explores the performance of novel vegetable oil-based greases containing polysaccharide gums as additives. Two series of greases with varying concentrations of gum acacia (GA) and guar gum (GG) are evaluated in a rolling bearing at various speeds and loads. The vibrations and shock pulse measurements (SPM) quantified the tribo-dynamics of the developed greases against two commercial greases used as the benchmark. The vibration and SPM assessment suggest that the newly developed eco-friendly greases are at par with the commercial ones; the performance varies with the concentration and type of gum. Where a cumulative effect of rheology and gum size seems to influence the vibrations, the entrainment of gums in the contact zone governs the SPM carpet values. The developed greases show great prospects as a sustainable, potential, and commercial alternative to existing environmentally unfriendly greases. [ABSTRACT FROM AUTHOR]

Conductive grease has been considered as a potential solution in addressing electric erosion issue inside motor bearings. Understanding the conductive grease performance, especially the electric and tribological behaviour is crucial for its application. This paper combines bulk grease characterization and contact film study considering both electrical and tribological loading conditions. The results show that the electric performance for the selected conductive grease sample is electric field dependent, including both frequency and voltage amplitude. Its film impedance inside the contact area is closely related to the external electric field, running condition, and lubrication regime. The following film impedance calculation tells that not only bulk grease electric parameters, but the contact parameter, lubricant film contour and lubrication condition should be considered when performing the overall bearing electrical modelling. [ABSTRACT FROM AUTHOR]

Controlled vacuum environments as in space applications represent a challenge for the lubrication of tribological components. In addition to common space lubricant requirements like, e.g., low evaporation, a broad operational temperature range and a high stability during operation, long-term-storage (LTS) properties have gained increasing attention recently. The term addresses the time-dependent stability of a lubricant under static conditions, which can mean chemical degradation processes such as oxidation on the one hand, but also the physical separation of oil and thickener in heterogeneous lubricants like greases. Due to the extended storage periods of lubricated components on-ground but also during a space mission for several years, it has to be ensured that a lubricant is still functional after LTS. This article depicts the development of a space lubricant grease with LTS properties. Firstly, LTS requirements and methods for their assessment are discussed. In the following, a systematic approach towards the design of a grease formulation compatible with LTS is described. Finally, the manufacturing of prototype formulations and their broad characterization by means of LTS behaviour, outgassing, and tribological performance is presented. [ABSTRACT FROM AUTHOR]

Background: The performance and endurance of lubricating greases is often assessed through model tests (like four-ball tests or SRV tests). This approach has some limitations, especially when greases with special fillers are investigated, because simplified laboratory test conditions can never replicate real operating conditions. Objective: For a more reliable assessment on the performance of a lubricating grease, lubricants must be tested in close-to-actual operational conditions, e.g. through component tests. This paper presents both the design and implementation of a dedicated test rig to test lubricating greases through middle-sized thrust ball bearings. Methods: The test rig design is optimized to monitor the effectiveness of lubrication and determine the useful life of grease by recording representative parameters, namely bearing temperature at different location in the bearing, vibration level, and electric contact resistance (ECR) through the bearing. Results: The results of a couple of assessment tests are presented and confirm that the test rig is working as expected. Conclusions: The chart of the parameters being monitored shows that the instant performance of grease lubrication can be tracked during the endurance tests, and grease failure identified. The special mechanical layout of the rig also allows the user to obtain additional information that is usually not available in other commercial greased bearing testers. This work is meant to be the first step of the development a new approach to evaluate the grease lubrication performance and a few experimental results are included as they are intended as a functional validation of the prototyped test rig.

Abstract Conductive grease has been considered as a potential solution in addressing electric erosion issue inside motor bearings. Understanding the conductive grease performance, especially the electric and tribological behaviour is crucial for its application. This paper combines bulk grease characterization and contact film study considering both electrical and tribological loading conditions. The results show that the electric performance for the selected conductive grease sample is electric field dependent, including both frequency and voltage amplitude. Its film impedance inside the contact area is closely related to the external electric field, running condition, and lubrication regime. The following film impedance calculation tells that not only bulk grease electric parameters, but the contact parameter, lubricant film contour and lubrication condition should be considered when performing the overall bearing electrical modelling.

Abstract The infrared (IR) absorption spectral data of 63 kinds of lubricating greases containing six different types of thickeners were obtained using the IR spectroscopy. The Kohonen neural network algorithm was used to identify the type of the lubricating grease. The results show that this machine learning method can effectively eliminate the interference fringes in the IR spectrum, and complete the feature selection and dimensionality reduction of the high-dimensional spectral data. The 63 kinds of greases exhibit spatial clustering under certain IR spectrum recognition spectral bands, which are linked to characteristic peaks of lubricating greases and improve the recognition accuracy of these greases. The model achieved recognition accuracy of 100.00%, 96.08%, 94.87%, 100.00%, and 87.50% for polyurea grease, calcium sulfonate composite grease, aluminum (Al)-based grease, bentonite grease, and lithium-based grease, respectively. Based on the different IR absorption spectrum bands produced by each kind of lubricating grease, the three-dimensional spatial distribution map of the lubricating grease drawn also verifies the accuracy of classification while recognizing the accuracy. This paper demonstrates fast recognition speed and high accuracy, proving that the Kohonen neural network algorithm has an efficient recognition ability for identifying the types of the lubricating grease.

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.)

The Historic England Zooarchaeology Reference Collection includes more than 3470 mammal, bird, amphibian, reptile and fish specimens, the majority of which are complete skeletons. It comprises important research collections that support internal, national and international projects, and is being continuously developed, mainly through in-house specimen preparation. The collection is housed in different locations at Fort Cumberland, an eighteenth-century military monument, and is therefore subject to varying environmental conditions, requiring tailored curation. This paper reports on an audit of the collection carried out in December 2016, in response to a perceived increase in the presence of insects, mould and grease, and the subsequent actions taken. The audit involved visual assessment and condition recording of each accessioned specimen. New specialist storage solutions were then implemented as part of the on-going collection curation, within the context of an integrated pest management strategy. [ABSTRACT FROM AUTHOR]

Grease, a type of lubricant, finds applications in various mechanical components due to advantages such as shape stability and sealing. However, grease is classified as a non-Newtonian fluid, and its film formation behavior is not fully understood to date due to variations in the mechanism related to the film formation behavior of grease based on factors like the base oil, bleed oil, thickener, and additives. In this study, the film formation behavior of fluorine-based grease was analyzed through the 3D profile of the grease after a friction test. In particular, the film formation behavior of the grease during sliding motion was analyzed. The experimental equipment used was a reciprocating-motion-type experimental equipment. Variations in the 3D profile were observed based on the speed and the cycle, indicating differences in the film formation behavior corresponding to changes in viscosity. In contrast to numerous studies that have observed the film formation behavior of grease under rolling motion, investigating the film formation behavior during the initial cycles of sliding motion will provide a profound understanding of the grease's film formation process. [ABSTRACT FROM AUTHOR]

This article describes a method for measuring the viscosity of oils that behave as Newtonian at low shear rates, by using only 80 μl of oil. This method is particularly useful when only such small quantities of oil are available—for example, when oil is extracted from grease taken from bearings. The method consists in placing an oil drop on blotter paper where an oil stain will grow in time. The rate of growth is then a measure of viscosity. Master curves were generated expressing the relation between viscosity and oil stain growth, both at a given time and as a function of time, each with its own accuracy. The viscosity measurements with this method were compared with those obtained in a conventional viscometer using poly-alpha-olefin (PAO), ester, and mineral oils. [ABSTRACT FROM AUTHOR]

Determining the film thickness during the bleeding phase of grease lubrication in a bearing is difficult due to the various replenishment and loss mechanisms involved. An additional factor that could influence the film thickness is the amount of grease in the bearing. In this study, film thickness is measured in deep-groove ball bearings using two different greases, each with initial grease filling percentages of 7.5%, 15%, and 30% of the bearing's free volume. Film thickness is measured during the early stage of the bleeding phase at various loads and speeds using the electrical capacitance method. Results show that, after churning, values of temperature and film thickness are similar for the three different filling quantities. This indicates that bulk grease flow or oil bleed from the reservoirs formed in the unswept region does not impact the lubricant film thickness in the early stage of bearing operation. [ABSTRACT FROM AUTHOR]

Increasing interest in utilizing bio-lubricants has been sparked by pollution caused by the mineral oil-based lubricants and their depletion. This study aimed to assess the effectiveness of Jatropha oil based grease as a basis and sodium thickener as an additive. The grease's lubricating abilities were tested using the ASTM 2266 four ball test and molybdenum disulphide as an additive. According to the findings, adding molybdenum disulphide particles decreased wear and the coefficient of friction, with the latter falling by 69% when compared to virgin Jatropha grease. Given that Jatropha grease passed the four ball test, a simulation of real-world conditions, this indicates that it is a reliable lubricant. Wear examinations were performed on steel balls using an optical microscope and scanning electron microscopy, and the results were consistent. It was found that addition of 0.25% MoS2 to virgin Jatropha grease reduced coefficient of friction to 0.12 (69%) from 0.39. Similarly wear scar diameter reduced from 800.583 µ to 788.44 µ in presence of 0.25% MoS2 blended grease. The study concludes that the grease prepared could an alternative to grease made from mineral oils. The focus on adopting Jatropha grease as a more sustainable and bio-degradable option can preserve the environment. [ABSTRACT FROM AUTHOR]

The protective properties and temperature resistance of sulfonate greases based on petroleum oil KS-19 have been assessed. Highly alkaline calcium sulfonates of Russian and foreign production are used as thickeners for such greases. Sulfonate greases have been shown to have good protective properties. It has been established that the ability of sulfonate greases to prevent corrosion depends on the protective properties of calcium sulfonate used as a thickener. Based on the totality of the indicators obtained, the grease based on the Russian-made K-314 thickener has the best properties; in temperature resistance, it is superior to the sample on the foreign thickener Lubrizol 86 GR, and in terms of protective properties, it is on the same level with it. [ABSTRACT FROM AUTHOR]

Mineral oil-based lubricants have been widely used for their beneficial properties. However, their environmental impact and toxicity have raised concerns, resulting in a search for sustainable and environmentally friendly alternatives. This study investigates the tribological behavior of palm olein-based grease with copper nanoparticles additive concentrations of 0.25 and 0.50 wt%. The friction and wear tests were conducted using a four-ball tribometer to evaluate the performance of the formulated grease and compare it with commercial mineral grease. The results showed that the palm olein-based grease with a 0.25 wt% copper nanoparticle additive concentration had excellent lubricant performance, with low friction and wear prevention characteristics. This concentration of Cu nanoparticles led to a 35.05% reduction in average friction coefficient (COF), a 32.56% reduction in wear scar diameter (WSD), and a 48.02% reduction in wear volume compared to pure palm olein-based grease. [ABSTRACT FROM AUTHOR]

Greased bearings in electric motors (EMs) are subject to a wide range of operational requirements and corresponding micro-environments. Consequently, greases must function effectively in these conditions. Here, the tribological performance of four market-available EM greases was characterized by measuring friction and wear of silicon nitride sliding on hardened 52100 steel. The EM greases evaluated had similar viscosity grades but different combinations of polyurea or lithium thickener with mineral or synthetic base oil. Measurements were performed at a range of temperature and surface roughness conditions to capture behavior in multiple lubrication regimes. Results enabled direct comparison of market-available products across different application-relevant metrics, and the analysis methods developed can be used as a baseline for future studies of EM grease performance.

Thickener, also known as a gelling agent, is a critical component of lubricating greases. The most critical property of thickener, temperature resistance, is determined by the molecular structure of the compounds. Currently, all high-temperature-resistant thickeners are based on 12-hydroxystearic acid, which is exclusively produced from castor oil. Since castor oil is also an important reagent for other processes, finding a sustainable alternative to 12-hydroxystearic acid has significant economic implications. This study synthesises an alternative thickener from abundant agricultural waste, cashew nut shell liquor (CNSL). The synthesis and separation procedure contains three steps: (i) forming and separating calcium anacardate by precipitation, (ii) forming and separating anacardic acid (iii) forming lithium anacardate. The obtained lithium anacardate can be used as a thickener for lubricating grease. It was found that the recovery of anacardic acid was around 80%. The optimal reaction temperature and time conditions for lithium anacardate were 100 °C and 1 h, respectively. The method provides an economical alternative to castor and other vegetable oils. The procedure presents a simple pathway to produce the precursor for the lubricating grease from agricultural waste. The first reaction step can be combined with the existing distillation of cashew nut shell processing. An effective application can promote CNSL to a sustainable feedstock for green chemistry. The process can also be combined with recycled lithium from the spent batteries to improve the sustainability of the battery industry. [ABSTRACT FROM AUTHOR]

The lubricating greases employed in this study were formulated with polyalphaolefin (PAO) 100 as the base oil and 12-lithium hydroxystearate as the thickener. The sol-gel method was used to produce the LaF3 nanoadditives. The oleic acid-treated LaF3 (i.e., OA-LaF3) and carboxylic acid-treated MWCNTs (i.e., COOH-MWCNTs) were blended in the formulated grease samples and used as nanoadditives. The detailed microstructural and chemical properties of chemically treated nanoadditives were investigated using HRTEM, XRD, FTIR and XPS analyses. Using a four-ball tester, the effect of different concentrations of nanoadditives on the tribo-performance of greases was investigated. Tribo-test results revealed the role of nanoadditives in PAObased grease lubrication performance. COOH-MWCNTs and OA-LaF3 nanoadditives outperformed PAO grease in terms of physicochemical and triboperformance for steel-steel tribo-pair. The improved tribo-performance is attributed to the formation of tribo-film on the contact interfaces via nanoadditives. The development of tribo-film was confirmed by XPS analysis of worn surfaces. [ABSTRACT FROM AUTHOR]