We report on the first encapsulated rotary ball bearing mechanism using silicon microfabrication and stainless steel balls. The method of capturing stainless steel balls within a silicon race to support a silicon rotor both axially and radially is developed for rotary micro machines and MEMS ball bearing tribology studies. Initial demonstrations show speeds up to 6.8 krpm without lubrication, w...

The purpose of this article is to review the relevant literature in machining using minimum quantity lubrication particularly as it pertains to environmental, and health issues , and outline future potential research in this technology. The results indicate that the process of mist particles generation and their physical characteristics are yet to be determined for a whole class of machining pr...

Recent studies have shown the existence of two types of discontinuous lipid structures in the synovial fluid lubricant film: (i) the lipid multilayers which form the synovial fluidcartilage interface [Purbach, Clin.Orthop.Relat.Res.2002], and (ii) lipid vesicles present within lubricant films [Watanabe, Med.Electron.Microsc.2000]. The size of these lipid vesicles, compared to the thickness of t...

Abstract. We consider here a discrete system of spheres interacting through a lubrication force. This force is dissipative, and singular near contact: it behaves like the reciprocal of interparticle distance. We propose a macroscopic constitutive equation which is built as the natural continuous counterpart of this microscopic lubrication model. This model, which is of the newtonian type, relie...

Synovial joints form the most important feature of the human body as they represent the centers of the most essential and basic activity in the human beings, which is motion. A synovial joint can be described as a load carrying system consisting of two mating bones with tangential and /or normal motions. The bone ends, which are usually spherical in appearance, are covered with a soft sponge li...

A thermodynamic model describing the phase transition of first order between structure states of lubricant material in the boundary friction regime is proposed. It is shown that lubricant melts with temperature increase or at shear of rubbing surfaces if the elastic strain (stress) exceeds the critical value. The phase diagram with domains of dry and sliding friction is constructed. The depende...

An analytical treatment for the sedimentation rate of disordered suspensions is presented in the context of a resistance problem. From the calculation it is confirmed that the lubrication effect is important in contrast to the suggestion by Brady and Durlofsky (Phys.Fluids 31, 717 (1988)). The calculated sedimentation rate agrees well with the experimental results in all range of the volume fra...

This paper addresses the dam-break problem for particle suspensions, that is, the flow of a finite volume of suspension released suddenly down an inclined flume. We were concerned with concentrated suspensions made up of neutrally buoyant non-colloidal particles within a Newtonian fluid. Experiments were conducted over wide ranges of slope, concentration and mass. The major contributions of our...