An understanding of the relationship between chemical structure and lubricant performance is highly desirable from both a fundamental and a practical perspective, such knowledge being vital to improve the performance of mineral oils and to guide the design of future synthetic lubricants. The rheological properties of alkanes of intermediate molecular size (C20–C40) are of particular interest as...

Melting of an ultrathin lubricant film confined between two atomically flat surfaces is studied using the rheological model for viscoelastic matter approximation. Phase diagram with domains, corresponding to sliding, dry, and two types of stick-slip friction regimes has been built taking into account additive noises of stress, strain, and temperature of the lubricant. The stress time series hav...

OBJECTIVE To compare the level of pain experienced by patients during transrectal ultrasound-guided prostatic biopsy using intrarectal 2% lidocaine gel versus plain lubricant gel. DESIGN Prospective double-blind randomised controlled trial. SETTING Regional hospital, Hong Kong. PATIENTS From March 2002 to December 2003, patients who underwent ultrasound-guided prostate biopsy at a Geriatr...

This paper presents the experimental results of normal lubricant, additives added lubricants and waste vegetable oil (WVO) contaminated bio-lubricants to evaluate the tribological properties such that friction and wear characteristics. The test was conducted using a four-ball tribotester with standard test method IP239. The balls used in four-ball tribotester were based on carbon-chromium steel...

In this work we study finite-size effects of nanoscale lubricant 2D droplets (or islands) by molecular dynamics. A small lubricant droplet is confined between two 2D crystalline layers; the bottom layer is static, while the top one slides rigidly. Simulations show that small nearly-lattice-matched islands can snap to commensuration entirely, changing their initial particleparticle distance ap t...

Tribological conditions can change drastically during heavy loaded regimes as experienced in metal forming; this is especially critical when lubrication can only be applied at the early stage of the process because the homogeneous lubricant layer can break along the die-workpiece interface. In these cases, adopting a constant friction factor for the lubricant-surface pair may not be a valid ass...

wind gearbOx technOLOgy is developing at a fast pace, not least due to operators demanding ever more power and efficiency. Experience has shown that the lubricant used is a crucial factor in meeting the wish for ever-increasing performance. Besides strictly technical requirements, aspects of economy and ecology are receiving more and more attention in lubricant selection. The technical requirem...

Squeeze film dampers are widely used in aircraft engines, land-based gas turbines, and other rotating machines to improve system damping. They often have entrained air within the oil film, which is usually not taken into account in rotordynamics analysis due to lack of good formulations of the effects involved. The effects on the damping force calculation can be significant. This work presents ...

A novel methodology, based on the use of phosphorescence imaging, is applied to determine the local through-thickness velocity profile of lubricant in an elastohydrodynamic contact. The technique has spatial and temporal resolutions of 40 μm and 340 μs respectively and thus allows lubricant rheology to be investigated at conditions close to service conditions. The capability of the newly-develo...

This study investigated the optimization of End milling of AISI 1018mild steel by various lubricants using the Grey relational analysis method. Quaker 7101, Blasocut strong 4000 and Velvex have been selected as lubricant. All the experiment are carried out at different cutting parameter (Number of Tool Flutes, Depth of cut, Spindle speed and Feed rate) in various lubricant assisted environment....