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The purpose of this paper is to investigate the tribological behaviour of commercially available SAE 10 mineral and rapeseed oils containing Fe particles synthesized directly in the oil phase.

Sub-micron Fe particles (50-340 nm) were synthesized by wet chemical reduction reaction of FeSO₄ by sodium borohydride in the rapeseed and mineral oils in the presence of surfactant: block copolymer (ENB 90R4) or oxyethylated alcohol (OS-20). A four-ball wear tribometer was used to investigate the tribological properties of mineral and rapeseed oil: coefficient of friction (COF), wear scar diameter and wear loss. Viscosity measurements of oil solutions and determination of synthesized Fe particles size were performed as well.

The presence of Fe particles (0.1 weight per cent) in the rapeseed and mineral oils caused the little change in the COF but resulted in marked improvement of anti-wear property. The oils containing Fe particles with slightly higher viscosity are giving more friction due to viscous drag. The anti-wear enhancement is attributed to the formation of tribofilm and superior load-bearing capability of the modified oil. Both rapeseed and mineral oils irrespective of used surfactant in the presence of 0.1 weight per cent Fe particles (50-140 nm) show sufficiently improved anti-wear properties.

The data collection about tribological behaviour of oils containing Fe particles and various additives in lubricants has a practical interest. The findings could be helpful to increase the knowledge of the behaviour of real tribological systems, where the metallic debris are generated during friction and contaminate the lubricating oil.

This paper focuses on the World Bank's emerging experience with a promising application of performance-based contracts: Output-Based Aid (OBA) subsidies. OBA is the provision of subsidies for the delivery of and access to social or infrastructure services. Under OBA, subsidy payments are tied to measurable performing outputs, leaving the specific methods of achieving these outputs to the service provider's discretion. While creating better risk allocation, more value for users and contracting agencies, and fewer opportunities for corruption than traditional methods, OBA schemes raise new procurement issues that need to be reconciled in order to achieve optimal results. An issue this paper explores is the tension between the need that contracts be "expenditure-based" with the "performance-based" nature of OBA subsidies.