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forces if stability is to be achieved. This links up with one of Professor Derjaguin's most important pieces of work published in 1942 in conjunction with the distinguished Russian physicist L. Landau. A similar independent wartime study by the Dutch physicists Verwey and Overbeek was published in 1948 and this immensely important contribution is known as the D L V O theory of colloid stability. In a letter written to me in September 1992 Professor Derjaguin writes that he finds great pleasure in using the Israelachvili instrument in his current surface studies, especially for the investigation of disjoining pressure. Clearly science is a country without frontiers. Professor Derjaguin's work is prodigious in quantity and striking for the new ideas that he and his numerous students and collaborators have introduced. His approach is characterized by ingenious experimental techniques, subtle and penetrating analyses, a critical combative style, a catholicity of outlook, an irrepressible and rather charming urge to claim priority wherever relevant, and the powerful integration of theory and experiment. In addition there is nearly always the suggestion of practical applications. Many of his ideas have entered into the broad stream of scientific thought. Naturally not all of his ideas have been accepted and some have generated vigorous controversy which I think he relishes: for sometimes I have the feeling that he enjoys the cut and thrust of the scientific dialectic 13. But none of these differences of opinion can detract from the quality of his work over many decades and the impact of his contributions to surface science. All workers in the field will be delighted to know that a selection of his papers is to be published in English in three volumes by Pergamon (London). Volume 1 is already in press. In his last letter to me he expressed his pleasure at receiving from the President of the G e r m a n Academy of Science greetings and TRIBOLOGY INTERNATIONAL
congratulations on the occasion of his 90th anniversary and on entering what Professor Derjaguin describes as the 'biblical' age. In this connection I cannot refrain from quoting that striking biblical phrase, which so aptly describes Boris Vladimirovich Derjaguin in his 91st year: 'His eye has not dimmed nor his natural force abated '14. Long may it so continue. David Tabor
References 1. Derjaguin B.V. Molecular theory of friction and sliding. Zh. Fiz. Khim., 1934, 5, 1165-1168
2. BowdenF.P. and Tabor D. Friction and Lubrication of Solids, Part 1, Cambridge University Press, UK, 1950
3. Tabor D. The role of surface and intermolecular forces in thin film lubrication, in Microscopic Aspects of Adhesion and Lubrication, (Ed. J.M. Georges) Elsevier, 1982, pp 651-679
4. Derjaguin B.V. ibid, p 680 5, Derjaguin B.V., Muller V.M. and Toporov Yu P. Effect of contact deformation
on the adhesion of particles. J Colloid Interface Sci., 1975, 53, 314-326 6. Johnson K.L., Kendall It. and Roberts
A.D. Surface energy and the contact of elastic solids. Proc. Ray. Soc. London, 1971, A324, 302-323 7. Tabor D. Surface forces and surface interactions. J. Colloid Interface Sci., 1977, 58, 2-13 8. Derjaguin B.V. et al., ibid, 1978, 67, 378; Tabor D. ibid, 1978, 67, 380; ibid, 1980, 73, 294 9. Muller V.M., Yushchenko V.S. and Derjaguin B.V. On the influence of
molecular forces on the deformation of an elastic sphere and its sticking to a rigid plane. J. Colloid Interface Sci., 1980, 77, 91-101 10. Tabor D. and Winterton R.H.S. The direct measurement of normal and retarded van der Waals forces. Proc. Roy. Soc. London, 1969, A312, 435-450 11. Israelachvili J.N. and Tabor D. The calculation of the van der Waals dispersion forces between macroscopicbodies. Proc. Roy. Soc. London, 1972, A331, 39-55
Intermolecular and Surface Forces, 2nd ed., Academic Press,
12. Israelachvili J.N.
London, 1991 13. Derjaguin B.V., Krotova N.A. and Smiiga V.P. Adhesion of Solids, Consult-
ants Bureau, NY, 1978, see Preface
14. Deuteronomy, 34, 7
General News Seventh BP Tribology Lecture The BP Tribology Lecture, sponsored by BP Group and run by the IMechE, is now almost a pre-Christmas tradition; it has become a firm favourite with which to close the Institution's annual programme of discussion meetings, seminars and conferences on the mechanical functioning of plant, machinery and their working components. This event at IMechE headquarters featured a lecture and state-of-the-art review paper on 'The behaviour of lubricants in contacts: current understanding and future possibilities' by Dr Hugh Spikes of the Department of Mechanical Engineering, Imperial College London. Since discovery in the 1960s, the processes of elasto-hydrodynamics ( E H D ) by which rolling bearings and gearing develop submicroscopically thin oil films to protect themselves against wear and seizure have proved a source of wonder to mechanical engineers and lubricant technologists alike. Highly loaded counterformal contacts could be expected to sequeeze out their lubricant and fail. In practice, they do just the opposite, squeezing the oils in place as they deform the hard steel bearings and gears, fortunately to an extent from which they recover quickly and repeatedly. Dr Spikes, with his team of young and enthusiastic researchers, has succeeded in rendering these unbelievably thin and transient oil films visible. In recent years they have built up a picture of the extent, thickness, temperature and shear conditions in the films, and are now in the process of determining the way in which the shape and structure of the lubricant molecules assist the separation and protection of highspeed contacts. The research had led to a series of valuable publications, of which 63
the present review paper is the latest and one of the most wideranging. The presentation was informative, stimulating and entertaining; nothing less, and perhaps a great deal more so than expected even of a seasoned professional lecturer. The lively half-hour of technical discussion which followed the lecture was opened, fittingly, by the Institution President Professor Dowson, a tribologist whose own contribution to the understanding of EHD has earned him most of the highest honours awarded to mechanical engineers.
Dr Spikes holding a commemorative plaque presented to him by Mr Bond to mark the occasion of the Seventh BP Tribology Lecture
64
The session closed with a vote of thanks to the speaker by Mr Robin Bond, Technical Adviser BP Engineering, whose remarks mirrored the enthusiastic reaction of the near-capacity audience in the Main Hall of the Institution.
1993 VOLUME 26 NUMBER 1
congratulations on the occasion of his 90th anniversary and on entering what Professor Derjaguin describes as the 'biblical' age. In this connection I cannot refrain from quoting that striking biblical phrase, which so aptly describes Boris Vladimirovich Derjaguin in his 91st year: 'His eye has not dimmed nor his natural force abated '14. Long may it so continue. David Tabor
References 1. Derjaguin B.V. Molecular theory of friction and sliding. Zh. Fiz. Khim., 1934, 5, 1165-1168
2. BowdenF.P. and Tabor D. Friction and Lubrication of Solids, Part 1, Cambridge University Press, UK, 1950
3. Tabor D. The role of surface and intermolecular forces in thin film lubrication, in Microscopic Aspects of Adhesion and Lubrication, (Ed. J.M. Georges) Elsevier, 1982, pp 651-679
4. Derjaguin B.V. ibid, p 680 5, Derjaguin B.V., Muller V.M. and Toporov Yu P. Effect of contact deformation
on the adhesion of particles. J Colloid Interface Sci., 1975, 53, 314-326 6. Johnson K.L., Kendall It. and Roberts
A.D. Surface energy and the contact of elastic solids. Proc. Ray. Soc. London, 1971, A324, 302-323 7. Tabor D. Surface forces and surface interactions. J. Colloid Interface Sci., 1977, 58, 2-13 8. Derjaguin B.V. et al., ibid, 1978, 67, 378; Tabor D. ibid, 1978, 67, 380; ibid, 1980, 73, 294 9. Muller V.M., Yushchenko V.S. and Derjaguin B.V. On the influence of
molecular forces on the deformation of an elastic sphere and its sticking to a rigid plane. J. Colloid Interface Sci., 1980, 77, 91-101 10. Tabor D. and Winterton R.H.S. The direct measurement of normal and retarded van der Waals forces. Proc. Roy. Soc. London, 1969, A312, 435-450 11. Israelachvili J.N. and Tabor D. The calculation of the van der Waals dispersion forces between macroscopicbodies. Proc. Roy. Soc. London, 1972, A331, 39-55
Intermolecular and Surface Forces, 2nd ed., Academic Press,
12. Israelachvili J.N.
London, 1991 13. Derjaguin B.V., Krotova N.A. and Smiiga V.P. Adhesion of Solids, Consult-
ants Bureau, NY, 1978, see Preface
14. Deuteronomy, 34, 7
General News Seventh BP Tribology Lecture The BP Tribology Lecture, sponsored by BP Group and run by the IMechE, is now almost a pre-Christmas tradition; it has become a firm favourite with which to close the Institution's annual programme of discussion meetings, seminars and conferences on the mechanical functioning of plant, machinery and their working components. This event at IMechE headquarters featured a lecture and state-of-the-art review paper on 'The behaviour of lubricants in contacts: current understanding and future possibilities' by Dr Hugh Spikes of the Department of Mechanical Engineering, Imperial College London. Since discovery in the 1960s, the processes of elasto-hydrodynamics ( E H D ) by which rolling bearings and gearing develop submicroscopically thin oil films to protect themselves against wear and seizure have proved a source of wonder to mechanical engineers and lubricant technologists alike. Highly loaded counterformal contacts could be expected to sequeeze out their lubricant and fail. In practice, they do just the opposite, squeezing the oils in place as they deform the hard steel bearings and gears, fortunately to an extent from which they recover quickly and repeatedly. Dr Spikes, with his team of young and enthusiastic researchers, has succeeded in rendering these unbelievably thin and transient oil films visible. In recent years they have built up a picture of the extent, thickness, temperature and shear conditions in the films, and are now in the process of determining the way in which the shape and structure of the lubricant molecules assist the separation and protection of highspeed contacts. The research had led to a series of valuable publications, of which 63
the present review paper is the latest and one of the most wideranging. The presentation was informative, stimulating and entertaining; nothing less, and perhaps a great deal more so than expected even of a seasoned professional lecturer. The lively half-hour of technical discussion which followed the lecture was opened, fittingly, by the Institution President Professor Dowson, a tribologist whose own contribution to the understanding of EHD has earned him most of the highest honours awarded to mechanical engineers.
Dr Spikes holding a commemorative plaque presented to him by Mr Bond to mark the occasion of the Seventh BP Tribology Lecture
64
The session closed with a vote of thanks to the speaker by Mr Robin Bond, Technical Adviser BP Engineering, whose remarks mirrored the enthusiastic reaction of the near-capacity audience in the Main Hall of the Institution.
1993 VOLUME 26 NUMBER 1