Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 27 for “"Boundary lubrication"”.
-
Molecular dynamics simulation of boundary lubrication
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1997.
-
Mixed and boundary lubrication in synovial joints
… and direct contact occurs within a mixed or boundary regime. Under these conditions friction must remain low to prevent damage to the articular cartilage. The lubrication mechanisms which continue to provide low friction and minimum wear in synovial joints are far from clearly understood and …
-
Ultrahigh vacuum studies of the boundary lubrication of metals
A novel ultrahigh vacuum (UHV) tribometer was used to study the tribological behavior of two Cu(111) surfaces modified by the adsorption of various atomic (sulfur, chlorine, iodine) and molecular (ethanol, trifluoroethanol, butanol, and heptafluorobutanol) species as a function of coverage. The …
-
Effect of fullerene containing lubricants on wear resistance of machine components in boundary lubrication
… of steel-bronze couples operating under boundary lubrication conditions. A mathematical model of deformed asperity contact was built to calculate real contact area and real contact pressure. Computer controlled wear friction testing methodology and equipment were designed, developed and …
-
Effects of piston design and lubricant selection on reciprocating engine friction
… efficiency. The model incorporated hydrodynamic, boundary, and mixed lubrication modes, and it allowed for either fully-flooded or partially-flooded skirts. It also considered the effects of skirt deformation in response to applied loads. A dominant factor influencing net friction between the …
-
Variation in joint fluid composition and its effect on the tribology of replacement joint articulation
… research, the effect of joint fluid on lubrication in the replaced joint has been largely overlooked. Several factors that affect the tribology of metal on polyethylene articulation in joint prostheses stem from the fluid lubricating the joint. In particular, the properties and …
-
Lubrication in the ball and socket joint of a swash plate mechanism
… not support the pressure so that hydrodynamic lubrication failed. Then, the dissipated friction power due to hydrodynamic shear was calculated over the range of crank angles where hydrodynamic lubrication applied. Results show that the dissipated power is essentially negligible. The frictional …
-
The effect of base stock and additive packages in an automotive oil on the friction and wear behaviour of overhead camshaft and finger follower systems
… using the mineral base oil under high load, boundary lubrication conditions. Scuffing also occurred under low load, mixed lubrication conditions using the case-hardened steel cam and chilled white iron follower combinations. The remaining cam materials, carbonitrided and induction hardened …
-
Design of Tribologically Enhanced Polymeric Materials for Biomedical Applications
… an undesirable event. Therefore, the need for lubrication arises to minimize the amount of shear stress that develops between opposing surfaces. This reduction in shear stress is characterized by the coefficient of friction (COF). Friction is one of the primary subjects of interest in …
-
Development of a multi-regime tribometer and investigation of zinc dialkyldithiophosphate tribofilm development in the presence of overbased calcium sulfonate
… was designed to operate in various conditions of lubrication severity, from boundary to hydrodynamic lubrication regimes. A cylinder-on-plate layout, in which a cylinder rotates and rubs against a plate in a line contact, was employed for this purpose. ZDDP, a wear preventative additive …
-
Effects of select fluids on the friction of metal-on-polyethylene joint replacement surfaces
… joint fluid directly affect the fluid film and boundary lubrication of artificial prostheses. Since the characteristics of joint fluids are likely to differ from patient to patient as a result of varying disease indications, age, health, gender, and activity level, tribological behavior is also …
-
Tribology of Sliding Contacts Within Plain Bearing Overlays Subject To Corrosion.
… lead-free bearing materials behave in different lubrication regimes such as mixed and boundary lubrication regime. The corrosion resistance of these materials also need to be especially within used lubricant conditions. In advance of tribology experiments a static immersion test is employed to …
-
A tribological study of the interaction between surface micro texturing and viscoelastic lubricants
… to obtain a Stribeck diagram that spans the lubrication regimes from boundary lubrication to hydrodynamic lubrication. Each lubricant/surface pair results in a unique curve that is subsequently compared to other lubricant/surface pairs in order to study the effect of different surface …
-
In situ control of lubricant properties for reduction of power cylinder friction through thermal barrier coating
… of increased metal-metal contact in mixed or boundary lubrication, for example near top ring reversal along the engine cylinder liner. A strategy to reduce viscosity without increased metal-metal contact involves controlling the local viscosity away from top-ring-reversal locations. This paper …
-
Proteoglycan-4 in Equine Joint Disease, Exercise, and in vitro Cartilage Repair
… contributions to tissue health and cartilage boundary lubrication. The biological consequences of joint injury or disease such as osteoarthritis (OA) may include altered concentration, structure, and function of PRG4 and HA, leading to degraded SF quality and function, changes which are not …
-
Tribology of engineering and coated materials in the presence of environmentally friendly refrigerant
… of HFO-1234yf refrigerant under aggressive boundary lubrication conditions. Specifically, we have performed controlled tribo-experiments, simulating actual automotive air-conditioning compressor systems, to measure in-situ friction and near-contact temperature. Interestingly, we have …
-
Tribopolymerization: Anti-Wear Behavior of New High Temperature Additive Classes
… of higher temperatures and inert surfaces, new lubrication methods for these ceramics need explored and evaluated. This thesis focuses on a boundary lubrication method termed tribopolymerization -- the formation of polymers at the tribological interphase. The research evaluated new …
-
Investigating Tempo-Oxidized Cellulose Nanofiber Lubricating Greases Using Microscopy, Rheology, and Tribology
… steady sliding wear curves revealed excellent boundary lubrication coefficient of friction performance in the range of 0.05-0.10 for all samples courtesy of both oleic acid and nanoparticle surface activity/tribofilm generation. It also revealed interesting high wear behavior at high relative …
-
Modeling piston skirt lubrication in internal combustion engines
… lacks a sufficient understanding of the skirt lubrication behavior to effectively optimize the piston skirt system in practice. The ultimate goal of this work is to develop a comprehensive model to advance the predictability of the skirt friction while integrating all the dynamic behavior of …
-
A Conditional approach to the tribology of RNLI marine systems.
… the other marine applications from an engine lubrication perspective, since it involves infrequent engine running conditions and is often subjected to either under or over engine maintenance due to the unpredictable usage of lifeboats. This research has demonstrated the key lubricant …
Page 1 of 2