Some aspects of the non-Newtonian behaviour of fluids in elastohydrodynamic lubrication.

In considering the experimental evidence for non-Newtonian behaviour, which has often been interpreted in terms of viscoelasticity, deviations from established theories, which assume a Newtonian fluid with viscosity dependent upon temperature and pressure, are sought. It is, therefore, vital to isolate inherent non-Newtonian behaviour from deviations arising from other unrelated processes. Non-Newtonian behaviour which has been detected is of two main types: inlet region effects (which may also arise from incomplete filling) and Hertzian zone effects (which may be attributed, at least in part, to the consequences of viscous heating). The thesis therefore presents a new theoretical analysis of the temperature distribution in the Hertzian zone and an analytical treatment of the effect of inlet starvation upon film thickness in order to aid the recognition of inherent non- Newtonian behaviour in the analysis of experiments. Experiments with markedly non-Newtonian lubricants (a series of silicones of differing chemical structure) are reported and an attempt is made to relate their hydrodynamic performance and degree of non-Newtonian behaviour to their molecular geometry. A four disc machine, employing a low elastic modulus (perspex) central specimen has been developed to examine non-Newtonian behaviour under conditions which reproduce the kinematics of low conformity contacts but which eliminate the influences of pressure and temperature whose unavoidable presence poses the major problem in the interpretation of experiments with conjunctions between metallic specimens. Excellent agreement is found between the experimental results and published non-Newtonian behaviour obtain from oscillatory shear measurements

Speculum matricis; or, the expert midwives handmaid. Catechistically composed by James Wolveridge, M.D. with a copious alphabetical index. Written IV Xta MagnaLIa DeI sCrIptor, anno Domini, 1669. Chronogramma, 1669 [electronic resource]

Printer's name from Wing CD.With an engraved frontispiece.The words 'Chronogramma, 1669.', on title page, are gathered by a left brace.Includes index.Reproduction of original in the Folger Shakespeare Library, Washington, D.C.Wing (CD-ROM, 1996)Electronic reproduction

Relationship between Supplied Oil Flow Rates and Oil Film Thicknesses under Starved Elastohydrodynamic Lubrication

Many studies have already considered starved lubrication. However, there have been no reports on the oil film thicknesses under steady starved EHL (elastohydrodynamic lubrication), where the ultra-low volume of oil supplied per unit time is uniform. The present study examined the relationship between the supplied oil flow rate and oil film thickness under steady starved lubrication. A ball-on-disk testing machine was used in experiments to measure the oil film thickness by means of optical interferometry. A microsyringe pump was used to accurately control the supplied oil flow rate. The supplied oil flow rate was kept constant, and the minimum oil film thickness was measured for 1 h after the start of the tests to determine the relationship between the supplied oil flow rate and oil film thickness