A low friction piston ring pack, with tangential load halved, was tested in engines with four different cylinder liner finishes. Oil consumption, oil temperature and liner surface temperature were monitored at different load and speed levels, under similar test conditions. The two smoother surfaces generally kept lower oil consumption compared to the two rougher ones. Results were correlated using an area-fractal analysis. The relative area of the surface was calculated at different scales and the result was compared with the level of oil consumption for the different liner surfaces at different engine speeds. It was found that oil consumption was strongly correlated with scale for areas of above 1000 μm² and below 20 μm².

A function map is used to locate applications of roughness in separation-velocity space. The importance of roughness in contact mechanics is demonstrated and versions of the plasticity index are introduced and compared. Case studies of roughness and function are presented from tribology and the life sciences. Tribological examples are taken from the automotive industry and include the manufacture of vehicle bodies, and drive train tribology, particularly cylinder liner, cam and gearbox friction and wear. From the life sciences, problems of prosthetic fixation and tribology are shown to depend on roughness. The interaction of haptics and surface finish is described and illustrated. A number of other areas of application are listed. Finally the likely future importance of structured surfaces is discussed. © 2014 IOP Publishing Ltd.

The Stedman diagram has been used for some years to display aspects of the performance of instruments measuring surface roughness. Such diagrams are herein employed to compare the features of a range of proprietary measuring instruments, including contact and non-contact devices. An extension of the basic diagram is proposed, which would allow it to include a further aspect: the speed of data collection. Figures of merit based on the revised diagram are computed, which enable instruments to be ranked on these particular aspects of their performance. Contact instruments emerge as comparable to non-contact, as their slower rate of data acquisition can be offset by the greater area they can access in amplitude–wavelength space. © 2014 IOP Publishing Ltd.

A taxonomy of applications is developed using the concept of function maps. The importance of roughness in contact mechanics is emphasised and alternative models of the plasticity index are revisited. The concept of contact resistance is shown to be strongly dependent on roughness. Further discussions are illustrated by a selection of case studies. Case studies from the life sciences include a discussion of dental and femoral prosthetics and architectural haptics. Tribological case studies are based on automotive problems, including manufacture of body parts, cylinder bore friction and lubrication, rocker cam wear and gear lubrication. It is concluded that the future of roughness studies lies with applications; that only a small number of currently available roughness parameters appear to have any practical use; and that much current work may eventually made obsolete by the increasing development of structured surfaces.

A function map is used to locate applications of roughness in separation-velocity space. The importance of roughness in contact mechanics is demonstrated and versions of the plasticity index are introduced and compared. Case studies of roughness and function are presented from tribology and the life sciences. Tribological examples are taken from the automotive industry and include the manufacture of vehicle bodies, and drive train tribology, particularly cylinder liner, cam and gearbox friction and wear. From the life sciences, problems of prosthetic fixation and tribology are shown to depend on roughness. The interaction of haptics and surface finish is described and illustrated. A number of other areas of application are listed. Finally the likely future importance of structured surfaces is discussed.

The Stedman diagram has been used for some years to display aspects of the performance of surface roughness measuring instruments. Such diagrams are herein employed to compare the features of a range of proprietary measuring instruments, including contact and non-contact devices. An extension of the basic diagram is proposed which would allow it to include a further aspect, speed of data collection. Figures of merit based on the revised diagram are computed which enable instruments to be ranked on these particular aspects of their performance. Contact instruments emerge as comparable to non-contact, as their slower rate of data acquisition can be offset by the greater area they can access in amplitude-wavelength space.

Traceology is defined as the study of wear marks and its history in criminology and archaeology is briefly described. It is proposed that the concept of traceology can be extended to machined surfaces, particularly those produced by abrasive techniques. A taxonomy of wear marks is outlined which would encompass both pits and scratches. Taxonomic implementations such as the morphology rose and the morphological tree are introduced. The general principles of traceology are illustrated by case studies from criminology, archaeology and abrasive machining processes.

Kenneth J. Stout was an important figure in the development of surface metrology, and in particular of roughness measurement and characterisation, during the last decades of the twentieth century. He made substantial contributions to the statistical characterisation of rough surfaces and the application of this work to tribological measurements. Later he was instrumental in developing and popularising practical techniques for three-dimensional description of surface roughness, including the well known "Birmingham 14" set of roughness parameters. Finally he was one of the first to promote the application of wavelet transforms to surface metrology. This memorial discusses his personal contribution to the subject and attempts to set it in the context of historical developments in the field. It includes what is hoped to be a definitive bibliography of his journal publications and those of his co-workers.