scholarly journals Inlet protein aggregation: a new mechanism for lubricating film formation with model synovial fluids

2011 ◽  
Vol 225 (7) ◽  
pp. 696-709 ◽  
Author(s):  
J Fan ◽  
C W Myant ◽  
R Underwood ◽  
P M Cann ◽  
A Hart
Keyword(s):  
Protein Aggregation ◽  
Film Formation ◽  
Lubricating Film ◽  
Synovial Fluids

scholarly journals Formulation of Sustainable Water-Based Cutting Fluids with Polyol Esters for Machining Titanium Alloys

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 773
Author(s):  
Elisabet Benedicto ◽  
Eva María Rubio ◽  
Laurent Aubouy ◽  
María Ana Sáenz-Nuño
Keyword(s):  
Molecular Structure ◽  
Tool Wear ◽  
Titanium Alloys ◽  
Film Formation ◽  
Cutting Fluid ◽  
Cutting Fluids ◽  
Lubricating Film ◽  
Wear Protection ◽  
Oil In Water ◽  
Polyol Esters

The machinability of titanium alloys still represents a demanding challenge and the development of new clean technologies to lubricate and cool is greatly needed. As a sustainable alternative to mineral oil, esters have shown excellent performance during machining. Herein, the aim of this work is to investigate the influence of esters’ molecular structure in oil-in-water emulsions and their interaction with the surface to form a lubricating film, thus improving the efficiency of the cutting fluid. The lubricity performance and tool wear protection are studied through film formation analysis and the tapping process on Ti6Al4V. The results show that the lubricity performance is improved by increasing the formation of the organic film on the metal surface, which depends on the ester’s molecular structure and its ability to adsorb on the surface against other surface-active compounds. Among the cutting fluids, noteworthy results are obtained using trimethylolpropane trioleate, which increases the lubricating film formation (containing 62% ester), thus improving the lubricity by up to 12% and reducing the torque increase due to tool wear by 26.8%. This work could be very useful for fields where often use difficult-to-machine materials—such as Ti6Al4V or γ-TiAl – which require large amounts of cutting fluids, since the formulation developed will allow the processes to be more efficient and sustainable.

scholarly journals Analysis of Chemisorbed Tribo-Film for Ceramic-on-Ceramic Hip Joint Prostheses by Raman Spectroscopy

2021 ◽  
Vol 12 (2) ◽  
pp. 29
Author(s):  
Risha Rufaqua ◽  
Martin Vrbka ◽  
Dušan Hemzal ◽  
Dipankar Choudhury ◽  
David Rebenda ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Hyaluronic Acid ◽  
Hip Joint ◽  
Total Joint Replacement ◽  
Film Formation ◽  
Frictional Coefficient ◽  
Synovial Fluids ◽  
Frictional Coefficients ◽  
Joint Prostheses ◽  
Ceramic On Ceramic

To understand the possible lubricant mechanism in ceramic-on-ceramic hip joint prostheses, biochemical reactions of the synovial fluid and the corresponding frictional coefficients were studied. The experiments were performed in a hip joint simulator using the ball-on-cup configuration with balls and cups made from two types of ceramics, BIOLOX®forte and BIOLOX®delta. Different lubricants, namely albumin, γ-globulin, hyaluronic acid and three model synovial fluids, were studied in the experiments and Raman spectroscopy was used to analyze the biochemical responses of these lubricants at the interface. BIOLOX®delta surface was found less reactive to proteins and model fluid lubricants. In contrast, BIOLOX®forte ball surface has shown chemisorption with both proteins, hyaluronic acid and model fluids imitating total joint replacement and osteoarthritic joint. There was no direct correlation between the measured frictional coefficient and the observed chemical reactions. In summary, the study reveals chemistry of lubricant film formation on ceramic hip implant surfaces with various model synovial fluids and their components.

scholarly journals Effect of Base Oil Type in Grease Composition on the Lubricating Film Formation in EHD Contacts

Lubricants ◽  
2018 ◽  
Vol 6 (2) ◽  
pp. 32 ◽  
Author(s):  
Dennis Fischer ◽  
Georg Jacobs ◽  
Andreas Stratmann ◽  
Gero Burghardt
Keyword(s):  
Film Formation ◽  
Base Oil ◽  
Lubricating Film ◽  
Grease Composition ◽  
Oil Type

Influence of the fatty acid profile on the lubricating film formation in micro-milling process on 7050-T7451 aluminum alloy

2019 ◽  
Vol 106 (1-2) ◽  
pp. 233-241 ◽  
Author(s):  
Milena Chanes de Souza ◽  
Hagen Maximilian Wiesner ◽  
Yves Kuche ◽  
Julian Polte ◽  
Jefferson de Oliveira Gomes ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Fatty Acid ◽  
Fatty Acid Profile ◽  
Film Formation ◽  
Milling Process ◽  
Micro Milling ◽  
Lubricating Film

The Effect of Kinematic Conditions on Film Thickness in Compliant Lubricated Contact

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
David Nečas ◽  
Tomáš Jaroš ◽  
Kryštof Dočkal ◽  
Petr Šperka ◽  
Martin Vrbka ◽  
...  
Keyword(s):  
Film Thickness ◽  
Optical Glass ◽  
Film Formation ◽  
Fluorescent Microscopy ◽  
Elastohydrodynamic Lubrication ◽  
Constant Load ◽  
Fluid Viscosity ◽  
Lubricating Film ◽  
Theoretical Predictions ◽  
Lubricated Contact

The present paper deals with an investigation of film formation in compliant lubricated contact. Despite these contacts can be found in many applications of daily life including both biological and technical fields, so far little is known about the lubrication mechanisms inside the contacts. The main attention is paid to the effect of kinematic conditions on central film thickness. For this purpose, fluorescent microscopy method was employed. Experiments were realized in ball-on-disk configuration, while the ball was made from rubber and the disk was from optical glass. The contact was lubricated by glycerol and polyglycol to examine the effect of fluid viscosity. The measurements were conducted under pure rolling and rolling/sliding conditions. The entrainment speed varied from 10 to 400 mm/s and constant load of 0.2 N was applied. Experimental results were compared with two theoretical predictions derived for isoviscous-elastohydrodynamic lubrication (I-EHL) regime. It was found that the thickness of lubricating film gradually increases with increasing entrainment speed, which corresponds to theoretical assumptions. Against expectations, evident influence of slide-to-roll ratio (SRR) on film formation was observed. In the last part of the paper, some limitations of this study are discussed and several recommendations for further methodology improvement are suggested.

Effect of Proteins on Film Formation in Bovine Serum Lubricated Contacts Under Rolling/Sliding Conditions

2012 ◽  
Author(s):  
Martin Vrbka ◽  
Tomas Navrat ◽  
Ivan Krupka ◽  
Martin Hartl ◽  
Jiri Gallo
Keyword(s):  
Film Thickness ◽  
Bovine Serum ◽  
High Speed ◽  
Film Formation ◽  
Research Work ◽  
Digital Camera ◽  
Protein Film ◽  
Lubricating Film ◽  
Ceramic Femoral Head ◽  
Optical Test

The aim of this study is to perform detail experimental mapping of the lubricating film thickness of bovine serum (BS) within the contact between an artificial metal or ceramic femoral head and a glass disc and analyze effect of proteins on the film formation under rolling/sliding conditions. The film thickness was studied experimentally using an optical test rig as a function of time under variety of constant mean speeds. Chromatic interferograms were recorded with a high-speed digital camera and evaluated with thin film colorimetric interferometry. Under pure rolling conditions it was observed that the central film thicknesses increased with time for all measurements. When the disc was slower than head then the measured central film thicknesses achieved values only about some few nanometres, whereas when the tests were realized with faster disc then measured central film thicknesses achieved significantly higher values. Distribution of the film thickness within the contact zone is not homogeneous and two different film thickness regions can be found; thicker protein film and thinner base film that both show specific behaviour over time. This study showed that protein formation plays an important role in the lubrication processes of artificial joints of the human. Due to challenging of this study the more complex research work is carried out at the present time.

scholarly journals Biotribology of Synovial Cartilage: A New Method for Visualization of Lubricating Film and Simultaneous Measurement of the Friction Coefficient

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2075
Author(s):  
Pavel Čípek ◽  
Martin Vrbka ◽  
David Rebenda ◽  
David Nečas ◽  
Ivan Křupka
Keyword(s):  
Friction Coefficient ◽  
Simultaneous Measurement ◽  
Film Formation ◽  
New Method ◽  
Cartilage Tissue ◽  
Evaluation Procedure ◽  
Synovial Joint ◽  
Friction Forces ◽  
Lubrication Film ◽  
Lubricating Film

A healthy natural synovial joint is very important for painless active movement of the natural musculoskeletal system. The right functioning of natural synovial joints ensures well lubricated contact surfaces with a very low friction coefficient and wear of cartilage tissue. The present paper deals with a new method for visualization of lubricating film with simultaneous measurements of the friction coefficient. This can contribute to better understanding of lubricating film formation in a natural synovial joint. A newly developed device, a reciprocating tribometer, is used to allow for simultaneous measurement of friction forces with contact visualization by fluorescence microscopy. The software allowing for snaps processing and subsequent evaluation of fluorescence records is developed. The evaluation software and the follow-up evaluation procedure are also described. The experiments with cartilage samples and model synovial fluid are carried out, and the new software is applied to provide their evaluation. The primary results explaining a connection between lubrication and friction are presented. The results show a more significant impact of albumin proteins on the lubrication process, whereas its clusters create a more stable lubrication layer. A decreasing trend of protein cluster count, which corresponds to a decrease in the thickness of the lubrication film, is found in all experiments. The results highlight a deeper connection between the cartilage friction and the lubrication film formation, which allows for better understanding of the cartilage lubrication mechanism.

Effect of Lubricant Scarcity on the Film Formation in an Inlet Zone During High Speed Cold Rolling Process

2007 ◽  
Author(s):  
Prahlad Singh ◽  
R. K. Pandey ◽  
Yogendra Nath
Keyword(s):  
Cold Rolling ◽  
High Speed ◽  
Heat Dissipation ◽  
Film Formation ◽  
Rolling Process ◽  
Lubricating Oil ◽  
Lubricating Film ◽  
Viscous Heat ◽  
Inlet Zone ◽  
Reduced Temperature

Effective lubrication during the cold rolling is vital in achieving desirable tolerance and surface quality over the metallic sheets. However, in the process of cold rolling, it has been established that the lubricant’s viscosity drastically reduces (viscosity thinning) due to huge viscous heat dissipation in the lubricating film at the elevated rolling speeds. Thinning of lubricant viscosity increases the escaping tendency of the lubricant from the inlet zone. Thus, scarcity (starvation) of lubricant prevails in the inlet zone of roll and strip interface. Based on the present investigation, it is observed that the existence of starvation seems to be beneficial in terms of reduced temperature rise and less quantity of lubricating oil required provided there is a continuous film at the strip-roll interface.

Sign in / Sign up

Export Citation Format

Share Document