Non-linear adsorption modeling of fatty esters and oleic estolide esters via boundary lubrication coefficient of friction measurements

Wear ◽  
2007 ◽  
Vol 262 (5-6) ◽  
pp. 536-544 ◽  
Author(s):  
Todd L. Kurth ◽  
Jeffrey A. Byars ◽  
Steven C. Cermak ◽  
Brajendra K. Sharma ◽  
Girma Biresaw
Keyword(s):  
Coefficient Of Friction ◽  
Boundary Lubrication ◽  
Fatty Esters ◽  
Adsorption Modeling ◽  
Non Linear ◽  
Friction Measurements

Adsorption Modeling of Fatty and Oleic Estolide Esters via Boundary Lubrication Coefficient of Friction Measurements

2005 ◽  
Author(s):  
T. L. Kurth ◽  
S. C. Cermak ◽  
J. A. Byars ◽  
G. Biresaw
Keyword(s):  
Boundary Lubrication ◽  
Adsorption Model ◽  
Fatty Esters ◽  
Cooperative Adsorption ◽  
Interaction Terms ◽  
Adsorption Modeling ◽  
Adsorption Energies ◽  
Friction Measurements ◽  
Negative Adsorption ◽  
Test Regime

The frictional behaviors of a variety of fatty esters (methyl palmitate (MP), methyl laurate (ML), and 2-ethylhexyl oleate (EHO)) and oleic estolide esters (methyl oleic estolide ester (ME) and 2-ethylhexyl oleic estolide ester (EHE)) as additives in hexadecane have been examined in a boundary lubrication test regime using steel contacts. Critical additive concentrations were defined and used to perform novel and simple Langmuir analyses that provide an order of adsorption energies: EHE ≥ ME > EHO > MP > ML. Application of a general adsorption model indicates slight cooperative adsorption of EHE, ME, and EHO. MP and ML data require larger attractive interaction terms (α ≤ −2.3) to be adequately fit. Irrespective of ester functionality increasingly negative adsorption energies appear to correlate with molecular weight. This suggests that multiple site coverage and multiple adsorptive interactions are likely for each of the esters studied.

scholarly journals Pengaruh Penambahan Minyak Kelapa dan Sawit Terhadap Sifat Fisik dan Tribologi Pelumas SAE 40

Jurnal METTEK ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Dedison Gasni ◽  
KM Abdul Razak ◽  
Ahmad Ridwan ◽  
Muhammad Arif
Keyword(s):  
Fatty Acids ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Palm Oil ◽  
Boundary Lubrication ◽  
Viscosity Index ◽  
Coconut Oil ◽  
High Viscosity ◽  
Mineral Oil ◽  
Lubricating Oil

Penelitian ini bertujuan untuk mengetahui efek dari penambahan minyak kelapa dan sawit terhadap sifat fisik dan tribologi pelumas SAE 40. Vegetabel oil, seperti; minyak kelapa dan sawit, memiliki nilai viskositas indek yang tinggi dan sifat pelumasan yang baik terutama didaerah boundary lubrication jika dibandingkan dengan mineral oil (SAE 40). Hal ini disebabkan karena vegetabel oil memiliki kandungan fatty acids yang tidak dimiliki oleh mineral oil. Keunggulan lain dari minyak kelapa dan sawit adanya sifat yang ramah lingkungan karena mudah terurai di alam dan dapat diperbaharui. Pada penelitian ini sifat yang baik dari minyak kelapa dan sawit ini akan dimanfaatkan sebagai zat aditif pada minyak pelumas SAE 40. Pengujian dilakukan terhadap sifat fisik dan tribology dengan penambahan 5%, 10%, 15%, dan 20% berat dari minyak kelapa dan sawit ke dalam minyak pelumas SAE 40. Pengujian sifat fisik terdiri dari pengukuran viskositas pada temperatur 400C dan 1000C dan viskositas index. Pengujian sifat tribologi untuk menentukan keausan dan koefisien gesek berdasarkan ASTM G99 dengan menggunakan alat uji pin on disk. Dari hasil pengujian diperoleh bahwa dengan penambahan minyak kelapa dan sawit kedalam minyak pelumas SAE 40 terjadi peningkatan viskositas indeks. Peningkatan viskositas indeks sebanyak  17% dengan penambahan 20% minyak sawit. Terjadi perubahan sifat tribologi dengan penambahan minyak sawit, berupa penurunan keausan dan nilai koefisien gesek dibandingkan dengan penambahan minyak kelapa. This study aims to determine the effect of coconut and palm oils as additives to physical and tribological properties of SAE 40 lubricating oil . Vegetable oils, such as; coconut oil and palm oil, have high viscosity index and good lubrication properties, especially in boundary lubrication compared to mineral oil. This is due to vegetable oil having fatty acids that are not owned by mineral oil. The advantages of coconut oil and palm oil are environmentally friendly properties because they are biodegradable and renewable. In this study, the good properties of coconut and palm oils will be used as additives in SAE 40 lubricating oil. Tests are carried out on the physical and tribological properties with the addition of 5%, 10%, 15%, and 20% by weight of coconut and palm oils into SAE 40 lubricating oil. Physical properties testing consists of measuring viscosity at temperatures of 400C and 1000C and viscosity index. The tribological test is to determine wear and coefficient of friction based on ASTM G99 using a pin on disc test equipment. From the test results,  it was found that coconut and palm oils as additives into SAE 40 lubricating oil could increase in viscosity index. The increase of  the viscosity index was 17% by adding 20% of palm oil. There was a change of tribological properties in the form of decreasing on the wear and the coefficient of friction with the addition of palm oil compare to addition of coconut oil.

Boundary lubrication of friction contacts steel/steel with Cr—DLC-coatings

2020 ◽  
pp. 558-563
Author(s):  
I.A. Buyanovskii ◽  
M.M. Khruschov ◽  
V.D. Samusenko ◽  
Yu.I. Schsherbakov ◽  
M.V. Atamanov ◽  
...  
Keyword(s):  
Experimental Study ◽  
Coefficient Of Friction ◽  
Boundary Lubrication ◽  
Tribological Characteristics ◽  
Coated Steel ◽  
Dlc Coatings ◽  
Dlc Coating ◽  
Lubrication Mode ◽  
Maximum Coefficient ◽  
Surface Active

The results of an experimental study of the tribological characteristics of inactive, surface-active, and chemically active lubricants in the boundary lubrication mode when steel is rubbed against steel with a carbon diamond-like (Cr—DLC)-coating. For comparison, also tested friction in these friction contacts under similar conditions, but without lubricant. The maximum coefficient of friction and maximum wear was obtained by tribological testing of steel on steel. The minimum coefficient of friction was obtained when steel was rubbed against Сr—DLC-coated steel in a surface-active lubricant medium.

Floor Slipperiness Measurement in a Food Factory

2013 ◽  
Vol 303-306 ◽  
pp. 769-772
Author(s):  
Kai Way Li ◽  
Ching Chung Chen ◽  
Li Wen Liu ◽  
Chih Yong Chen
Keyword(s):  
Coefficient Of Friction ◽  
Safety Standard ◽  
The Usa ◽  
The Coefficient Of Friction ◽  
Friction Measurements ◽  
Ergonomic Interventions ◽  
Northern Taiwan

Floor slipperiness assessment was conducted in a food factory in northern Taiwan. Three areas in the popcorn sector of the factory were measured. The friction measurements were conducted using the Brungraber Mark II slipmeter. A total of 96 measurements of the coefficient of friction on the floor were conducted. In addition, six employees were interviewed concerning their experiences of slipping and falling in the sector and their perception of floor slipperiness. The results showed that all the readings in the measurement areas were lower than 0.5, a safety standard commonly adopted in the USA. All the interviewees reported that they had the experiences of slipping without falling in the sector. All of them reported the floor in the popping area was “extremely slipperiness.” Ergonomic interventions are required and in this sector.

Coefficient of Friction Measurements on Transfemoral Amputees

Biotribology ◽  
2020 ◽  
Vol 22 ◽  
pp. 100126
Author(s):  
Sofía C. Henao ◽  
Simón Cuartas-Escobar ◽  
Juan Ramírez
Keyword(s):  
Coefficient Of Friction ◽  
Transfemoral Amputees ◽  
Friction Measurements

Variation with load of the coefficient of friction and metallic transfer under conditions of boundary lubrication

1952 ◽  
Vol 212 (1111) ◽  
pp. 516-519 ◽  
Keyword(s):  
Coefficient Of Friction ◽  
Boundary Lubrication ◽  
General Pattern ◽  
Copper Plate ◽  
Experimental Conditions ◽  
Average Hardness ◽  
Boundary Lubricant ◽  
The Coefficient Of Friction ◽  
Fixed Load ◽  
Molecular Layers

Several papers have been published recently which show for a number of metals that, under certain experimental conditions, several molecular layers of boundary lubricant are necessary to give effective lubrication, i.e. a coefficient of friction of 0.1 or less. Recent experiments by the authors suggest that these results represent parts of a more general pattern. In the previous work, the experiments were carried out at a fixed load; in the present, the load has been varied. The apparatus used was a copy of that described by Bowden & Leben (1939) for studying friction at low speeds of sliding. A hemispherical copper slider of radius 0-45 cm was caused to slide upon a flat copper plate at a speed of approximately 1 cm/min. Several specimens were used; their average hardness was 100 v .p .h .

Analysis of the Contribution of Adhesion and Ploughing to Shoe-Floor Lubricated Friction in the Boundary Lubrication Regime

2011 ◽  
Author(s):  
Caitlin Moore ◽  
Kurt Beschorner ◽  
Pradeep L. Menezes ◽  
Michael R. Lovell
Keyword(s):  
Coefficient Of Friction ◽  
Boundary Lubrication ◽  
Ambient Conditions ◽  
Lubrication Regimes ◽  
Lubrication Regime ◽  
Material Hardness ◽  
Lubrication Layer ◽  
The Coefficient Of Friction ◽  
Dry Conditions ◽  
Pin On Disk

Slip and fall accidents cost billions of dollars each year. Shoe-floor-lubricant friction has been shown to follow the Stribeck effect, operating primarily in the boundary and mixed-lubrication regimes. Two of the most important factors believed to significantly contribute to shoe-floor-lubricant friction in the boundary lubrication regime are adhesion and ploughing. Experiments were conducted using a pin-on-disk tribometer to quantify adhesion and ploughing contributions to shoe-floor friction in dry and lubricated conditions. The coefficient of friction between three shoe materials and two floor materials of different hardness and roughness were considered. Experiments were conducted under six lubricants for a sliding speed of 0.01 m/sec at ambient conditions. It was found that the contribution of adhesion and ploughing to shoe-floor-lubricant friction was significantly affected by material hardness, roughness, and lubricant properties. Material hardness and roughness are known to affect adhesion, with increased hardness or increased roughness typically resulting in decreased adhesion. The smoothest shoe material, while also being the hardest, resulted in the greatest adhesional contribution to friction. The roughest material, while also being the softest, resulted in the lowest adhesional contributions under dry conditions. Canola oil consistently resulted in the lowest percent of full adhesion and water consistently resulted in the highest percent of full adhesion, presumably due to the thickness, of the boundary lubrication layer. Ploughing contribution was dependent upon the hardness of the shoe and floor materials. A positive correlation was found between the shoe and floor hardness ratio and ploughing coefficient of friction.

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