The Kramers problem in the energy-diffusion limited regime of very low friction is difficult to deal with analytically because of the repeated recrossings of the barrier that typically occur before an asymptotic rate constant is achieved. Thus, the transmission coefficient of particles over the potential barrier undergoes oscillatory behavior in time before settling into a steady state. Recentl...

It is a convenient approximation to regard the frictional forces between two solids as made up of two components: the force required to shear adhering junctions in the region of surface contact and the force required to deform the underlying bulk material.' With an elastic solid, the deformation component may be due mainly to an elastic hysteresis loss; but if plastic flow occurs, the deformati...

Normal articular cartilage is characterized by a smooth surface with very low friction and the ability to withstand repeated high loads. Loss of this smooth surface leads to pain, loss of motion, swelling and eventually deformity. This will ultimately result in degenerative osteoarthritis.(1,2) A variety of methods have been developed over the past 20 years and are now available to regenerate c...

Pipe systems are often used to transfer moderate to medium water volumes between reservoirs or from well fields to consumers. Such systems consisting of an arbitrary number of reservoirs or other types of sources and sinks are considered here. The Lagrangean optimization principle is used for the determination of all pipe diameters giving minimum total cost of the system, when the individual di...

Compared to mechanical bearings, active magnetic bearings eliminate friction, resulting in lower energy losses. However, due the magnetization characteristics and high-frequency working of core material bearing, there will be high wind friction loss, eddy current hysteresis loss copper bearing. These losses generate heat increase internal temperature which not only affect control accuracy beari...

Journal bearings in hermetic reciprocating compressors are analyzed experimentally as well as numerically. The motor current and the load applied to the bearing are measured to obtain the performance curve of the journal bearing, from which the critical Sommerfeld number is derived. In the numerical analysis, the Reynolds equation and equilibrium equations of the journal center are solved simul...

Objective: To estimate the economic burden of coronary heart disease in the UK using both direct and indirect costs. Design and setting: A prevalence based approach was used to assess coronary heart disease related costs from the societal perspective. Patients: All UK residents in 1999 with coronary heart disease (ICD 9 codes 410–414 and ICD10 codes I20–I25). Main outcome measures: Direct healt...