Using molecular dynamics based on Langevin equations with a coordinate- and velocity-dependent damping coefficient, we study the frictional properties of a thin layer of "soft" lubricant (where the interaction within the lubricant is weaker than the lubricant-substrate interaction) confined between two solids. At low driving velocities the system demonstrates stick-slip motion. The lubricant ma...

Diesel particulate filters (DPF) are an effective means for meeting increasingly stringent emissions regulations that limit particulate matter. Over time, ash primarily derived from metallic additives in the engine oil accumulates in DPFs. Lubricant-derived ash increases pressure drop and reduces fuel economy. After long time periods, the accumulation of ash may lead to irreversible plugging in...

The tribology properties of TiO2/POE, SiO2/POE and TiO2-SiO2/POE nanolubricants were investigated for an automotive air-conditioning system with electrically-driven compressor (EDC). A two-step preparation method was used in dispersing TiO2 SiO2 nanoparticles into Polyol-ester (POE)-based lubricant at different volume concentrations 0.01 to 0.1%. coefficient friction (COF) wear scar diameter (W...

AbstractSputtered MoS2 coatings have been mostly used as a solid lubricant. In this investigation, MoSx/Ni composite coatings with Ni contents varying from 0 to 22 % were deposited onto steel substrate using a DC magnetron sputter process. The MoS2/Ni ratio in the coatings was controlled by sputtering the composite targets. The composition, microstructure, and mechanical properties of the...

Synthetic substrates that mimic the properties of extracellular matrix proteins hold significant promise for use in systems designed for tissue engineering applications. In this report, we designed a synthetic polymeric substrate that is intended to mimic chemical, mechanical, and topological characteristics of collagen. We found that elastomeric poly(ester amide) substrates modified with repli...

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...

A partially purified preparation of an alpha-amino acid ester hydrolase was obtained from Acetobacter turbidans A.T.C.C. 9325, which catalyses synthesis of 7-(d-alpha-amino-alpha-phenylacetamido)-3-cephem-3-methyl-4- carboxylic acid (cephalexin) from methyl d-alpha-aminophenylacetate and 7-amino-3-deacetoxycephalosporanic acid. The enzyme preparation catalysed both cephalosprin synthesis from 7...

A new and practical microwave (MW)-assisted method was developed for the fast efficient oxidative addition of secondary phosphine oxides or alkyl phenyl-H-phosphinates acetylenes. The reaction optimized in respect agent, time, temperature molar ratio starting materials. protocol enabled synthesis novel benzo[b]phosphole oxide derivatives under mild conditions a short time. By use special reagen...

According to the latest research, nanofluids as a possible future substitution for high-voltage equipment insulation have potential enhance heat transfer and properties of their base fluids. Dielectric are represented by breakdown strength (AC, DC, lightning) dielectric performance set quantities including dissipation factor, permittivity, volume resistivity. In this study, natural synthetic es...