Search results for "Lubrication"
showing 10 items of 24 documents
A Numerical Approach to Finite Journal Bearings Lubricated With Ferrofluid
1987
Several cases of cylindrical bearings lubricated with ferrofluid are examined by means of a finite-difference numerical procedure. The subregion of cavitation is determined by imposing mass conservation across the “rupture” and “reformation” boundaries of the complete film. The examined cases refer to bearings confined by sealing rings formed by the lubricant itself, for which there is no need of external supply. In each case the most significant parameters are calculated and it is possible to see that the use of these bearings is favorable when speeds are low, clearances large, and loads light, because in such conditions the magnetic effects are comparable with the pure hydrodynamic ones a…
Comparative study of the lubricant performance of Compritol® HD5 ATO and Compritol® 888 ATO: effect of polyethylene glycol behenate on lubricant capa…
2003
The aim of this paper is to study the lubricant capacity of Compritol HD5 ATO, a glyceryl and polyethylene glycol dibehenate, obtained by atomization. This material is compared to Compritol 888 ATO, constituted only by glyceryl dibehenate. First, this study verifies that Compritol HD5 ATO and Compritol 888 ATO present the same granular characteristics and that their mixes with Lactopress present no structural differences. Secondly, in term of compressibility and cohesiveness, the use of Compritol 888 ATO or Compritol HD5 ATO with Lactopress does not involve any significant modification. Finally, the minor difference of lubricant capacity between Compritol HD5 ATO and Compritol 888 ATO has n…
Impact of saliva and astringent compounds on tongue mechanical properties : an ex vivo investigation
2018
International audience
The Surface of Ice under Equilibrium and Nonequilibrium Conditions
2019
ConspectusThe ice premelt, often called the quasi-liquid layer (QLL), is key for the lubrication of ice, gas uptake by ice, and growth of aerosols. Despite its apparent importance, in-depth understanding of the ice premelt from the microscopic to the macroscopic scale has not been gained. By reviewing data obtained using molecular dynamics (MD) simulations, sum-frequency generation (SFG) spectroscopy, and laser confocal differential interference contrast microscopy (LCM-DIM), we provide a unified view of the experimentally observed variation in quasi-liquid (QL) states. In particular, we disentangle three distinct types of QL states of disordered layers, QL-droplet, and QL-film and discuss…
On the tribology and rheology of polymer brushes in good solvent conditions: a molecular dynamics study
2003
Tribological and rheological properties of two polymer brushes in relative sliding motion and good solvent conditions are investigated by means of molecular dynamics (MD) simulations. The lateral forces between the brushes are found to decrease logarithmically with increasing relative sliding velocity v0 over a range of more than one decade in v0. We also observe an almost logarithmic relaxation of the end-to-end distance vector that occurs after sliding is stopped. The coincidence of these logarithmic dependencies support the picture that friction between polymer brushes is small due to the retraction of the polymers from the interpenetration zone. The shear stress relaxes almost instantly…
Elastohydrodynamic Collision of Two Spheres Allowing Slip on Their Surfaces.
2000
Our goal is to study theoretically the effect of deformation on the collision of two solid spheres allowing slip on their surfaces. The deformed shape of the solid surface is determined via an asymptotic technique assuming that deformation is small compared with the separation between the surfaces. It has previously been shown that the slippage makes collision possible even without any surface attractive force. Here we demonstrate that even a small amount of deformation can preclude spheres from coagulation. Copyright 2000 Academic Press.
Sexual Dysfunctions and Their Association with the Dual Control Model of Sexual Response in Men and Women with High-Functioning Autism
2019
Adults with an Autism Spectrum Disorder (ASD) are characterized by impairments in social interaction and communication, repetitive and stereotyped interests and behaviours as well as hyper- and/or hyposensitivities. These disorder specific symptoms could be associated with the development of sexual disorders. The Dual Control Model of Sexual Response presents one approach that is frequently used to explain the emergence of sexual dysfunctions. The aim of the present study was to assess the extent of symptoms of sexual dysfunctions in men and women with ASD and to evaluate their association with the individual propensity of sexual excitation and inhibition as defined by the Dual Control Mode…
Thermo-optical mirror on a free ferrofluid surface
1997
Here we report on the first, to our knowledge, direct experimental observation of giant thermo-optical mirror effect on the free surface of ferrofluid under He-Ne laser excitation. In our experiment a slightly focused laser beam of power in mW range is incident nearly normally to the surface, and a characteristic diffraction ring pattern has been observed in reflection mode. Concave surface deformation has been clearly observed at laser irradiated spot and has been explained in terms of lubrication theory approach for laser driven thermocapillary motion in thin layer of light absorbing fluid.
Comparative study of the lubricant performance of Compritol 888 ATO either used by blending or by hot melt coating.
2003
Compritol 888 ATO is used as a lubricant in oral solid dosage formulations. It can also be used as a hot melt coating agent sprayed onto a powder. In this study, we compare the lubricant performance of Compritol 888 ATO either used by classical blending or by hot melt coating onto Lactopress by compression tests. In physical mix, the Compritol concentration does not affect the compressibility. The same compressibility is obtained with lactose coated by 0.5 or 1% of Compritol, but a higher compressibility can be observed with 2 and 3%. Cohesiveness of lactose depends on the process: hot melt coating induces a decrease of tablet tensile strength. In terms of forces transmission during compres…
Friction and wear of lubricated M3 Class 2 sintered high speed steel with and without TiC and MnS additives
2005
Abstract M3/2 sintered high speed steel and composite materials processed by initial admixing of 5 wt.% TiC (to decrease wear) and 5 wt.% MnS (to minimise friction) powders, singly and in combination, were assessed in pin-on-disc tribometers specially constructed to simulate use in the automotive valve train. Pins were of the sintered materials and the mating tribological material discs of T1 high speed steel. For comparison with existing conventional materials, identical tests were performed with discs and pins of two types of spheroidal cast iron. Testing at ∼110 °C, employing a few drops of fresh Shell Helix Standard SAE: 15W-40, API: SJ/CF oil, in daily segments of 5000 m of sliding dis…