Knowledge

Welcome to our knowledge centre. Here you can find a selection of resources and articles on our products and industries we are involved with.

Spotlight Paper

The Influence of Bearing Grease Composition on Friction in Rolling/Sliding Concentrated Contacts

Some outstanding grease research carried out by a team of great experimentalists using both the MTM and EHD rigs. The …

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Some outstanding grease research carried out by a team of great experimentalists using both the MTM and EHD rigs. The novel methodology employed showed how it is possible to disentangle the behaviour of the grease thickener from that of the base oil, which is then used to explain the characteristic “bump” observed in some grease Stribeck curves. The illuminating research concludes that greases exhibit two distinct operating regions, in terms of friction and film thickness. A must read for anyone involved in this sometimes challenging area of tribology research.

Open Access Link:
https://www.sciencedirect.com/science/article/pii/S0301679X15004612

PCS review

Spotlight Paper

Prediction of Micropitting Damage in Gear Teeth Contacts Considering the Concurrent Effects of Surface Fatigue and Mild Wear

Although sometimes presented as a seemingly random and somewhat unpredictable sequence of events, this paper shows a high level of …

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Although sometimes presented as a seemingly random and somewhat unpredictable sequence of events, this paper shows a high level of details and understanding of the mechanisms involved. A detailed introduction to micropitting is leads on to discussion and presentation of an excellent modelling technique. Predictions made by the model are compared to actual micropitting results, and pleasingly, are able to accurately predict the degree of micropitting. The paper is more of a 3 course meal than a light lunch, so pull up a chair and enjoy a large serving of micropitting knowledge!

Open Access Link:
https://www.sciencedirect.com/science/article/pii/S0043164817309535

PCS review

Paper

Surface Adsorption and Lubrication Properties of Plant and Dairy Proteins: A Comparative Study

The aim of this work was to compare the surface adsorption and lubrication properties of plant and dairy proteins. Whey …

The aim of this work was to compare the surface adsorption and lubrication properties of plant and dairy proteins. Whey protein isolate (WPI) and pea protein isolate (PPI) were chosen as model animal and plant proteins, respectively, and various protein concentrations (0.1–100 mg/mL) were studied with/without heat treatment (90 °C/60 min). Quartz crystal microbalance with dissipation monitoring (QCM-D) experiments were performed on hydrophilic (gold) and hydrophobic polydimethylsiloxane (PDMS) sensors, with or without a mucin coating, latter was used to mimic the oral surface. Soft tribology using PDMS tribopairs in addition to wettability measurements, physicochemical characterization (size, charge, solubility) and gel electrophoresis were performed. Soluble fractions of PPI adsorbed to significantly larger extent on PDMS surfaces, forming more viscous films as compared to WPI regardless of heat treatment. Introducing a mucin coating on a PDMS surface led to a decrease in binding of the subsequent dietary protein layers, with PPI still adsorbing to a larger extent than WPI. Such large hydrated mass of PPI resulted in superior lubrication performance at lower protein concentration (≤10 mg/mL) as compared to WPI. However, at 100 mg/mL, WPI was a better lubricant than PPI, with the former showing the onset of elastohydrodynamic lubrication. Enhanced lubricity upon heat treatment was attributed to the increase in apparent viscosity. Fundamental insights from this study reveal that pea protein at higher concentrations demonstrates inferior lubricity than whey protein and could result in unpleasant mouthfeel, and thus may inform future replacement strategies when designing sustainable food products.

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Paper

Less Corrosive Organomolybdenum Compounds as Lubricant Additives

This invention involves the development of less corrosive, high performing organomolybdenum compounds with applications as additives in lubricants. Lubricants containing …

This invention involves the development of less corrosive, high performing organomolybdenum compounds with applications as additives in lubricants. Lubricants containing these compounds have demonstrated improved performance with respect to friction reduction, wear protection, and copper and lead corrosion, in particular for diesel and passenger car engine oil applications where high performing, more durable additives are required in terms of oxidative and hydrolytic stability.

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Paper

Synergy and Enhanced Performance Retention With Organic and Molybdenum Based Friction Modifier Combination

An improved organic and molybdenum friction modifier combination is disclosed, the combination resulting in a synergistic result of both initial …

An improved organic and molybdenum friction modifier combination is disclosed, the combination resulting in a synergistic result of both initial friction reduction performance and a further retention and durability of continued friction reduction performance. These results will produce added benefit from, e.g., formulated passenger car motor oils targeting lower viscosity formulations to help improve fuel economy.

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Paper

Optimized Production of Fatty Acid Ethyl Esters (FAEE) from Waste Frying Oil by Response Surface Methodology

In Europe, recent regulations on advanced biofuels have prompted a search for new fuel sources and the development of synthesis …

In Europe, recent regulations on advanced biofuels have prompted a search for new fuel sources and the development of synthesis methods meeting the demanding specifications of the sector. However, in developing countries such as Algeria, where a significant stock of frying oil is unused, the use of diesel engines powered with waste-oil-derived biofuels must be explored. In this work, the variables related to the transesterification reaction from this frying oil with ethanol are analyzed using response surface methodology. From this analysis, only the reaction time and temperature have been determined as relevant parameters. In addition, FT-IR analysis has proven a useful tool to analyse the conversion in the transesterification reaction of waste frying oil with ethanol and is cheaper and quicker than GC-FID. This sustainable biofuel (FAEE), mixed with a diesel and pure fuel, has been physically characterized. The mixture of FAEE at 30% by volume with diesel meets the requirements demanded in standard EN 590 and can be classified as winter diesel class D. As a pure biofuel, only its high cold flow temperatures could constitute a drawback for exporting to temperate climates but not for internal consumption.

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Paper

Tribological Performance of 52,100 Steel Subjected to Boron-doped DLC Coating and Ultrasonic Nanocrystal Surface Modification

The tribological performance of AISI 52100 substrates subjected to several surface treatments have been evaluated in rolling, sliding, and mixed …

The tribological performance of AISI 52100 substrates subjected to several surface treatments have been evaluated in rolling, sliding, and mixed mode contact. The surface treatments include a boron-doped diamond-like carbon (B-DLC) coating deposited by plasma-assisted magnetron sputtering, an ultrasonic nanocrystal surface modification (UNSM) technique used to generate severe plastic deformation in the near surface of the steel specimens, and a B-DLC coating applied to a UNSM pretreated surface. In general, the tribological performance of the duplex surface treatment was superior to that of the untreated specimens and of the specimens with the other surface treatments in rolling, sliding, and mixed mode contact. The improved tribological performance of the duplex process was attributed to the combination of increased wear resistance provided by the B-DLC coating and the grain refinement of the martensitic structure of the AISI 52100 imparted by the UNSM process that created a beneficial substrate/coating interface.

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