Kinetic boundary friction

It is shown that the exhibition of smooth sliding and relaxation oscillations, or ‘stick-slips’, under conditions of boundary lubrication, when frictional forces are measured by the deflexion of an elastic system, may be explained as due to the dependence of kinetic friction on velocity. In the cases giving smooth sliding, kinetic friction decreases as velocity decreases, at very low speeds; for the cases giving relaxation oscillations kinetic friction increases as velocity decreases. That is, sliding under boundary conditions is not inherently discontinuous, any discontinuous motion being due to the dynamics of the measuring instrument, and is the result of kinetic friction increasing as velocity decreases. Curves of boundary friction against velocity, using various slicing surfaces, have been determined for a number of lubricants, which show both the above-mentioned types of friction-velocity relationship; and the dependence is shown of kinetic boundary friction on molecular weight for a series of esters of the fatty acids, on percentage of fatty oil in a compounded lubricant (actually oleic acid in mineral oil) and on temperature for a pure substance and a mineral oil. The measurements with the series of esters show some agreement with results given by Fogg (1940). The mixtures of oleic acid with mineral oil give decreasing kinetic friction with increasing percentage of oleic acid right up to 100% oleic acid. The effect of temperature on the dependence of friction in velocity shows that the temperature at which relaxation oscillations first occur depends on the speed of sliding, from which it appears that measurements of the temperature at which relaxation oscillations start at constant sliding speed (Frewing 1942) are not a measure of the temperature at which there is a discontinuity in the properties of the boundary layer.

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Oleic acid as a synergistic agent in the formation of kaolinite-mineral oil Pickering emulsions

Applied Clay Science ◽

10.1016/j.clay.2021.106378 ◽

2022 ◽

Vol 216 ◽

pp. 106378

Author(s):

Priscila Gritten Sieben ◽

Fernando Wypych ◽

Rilton Alves de Freitas

Keyword(s):

Oleic Acid ◽

Mineral Oil ◽

Pickering Emulsions ◽

Synergistic Agent

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Rheological Comparison of Fatty Oil with Mineral Oil

Journal of Japan Oil Chemists Society ◽

10.5650/jos1956.9.186 ◽

1960 ◽

Vol 9 (4) ◽

pp. 186-191

Author(s):

Masumi KINOSHITA ◽

Toshitaro OGUCHI ◽

Masuhiro ONOYAMA ◽

Kazumi TSUDA

Keyword(s):

Mineral Oil ◽

Fatty Oil

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Optimization of Pyrolysis Operating Condition for Deriving Corn Starch Heterogeneous Acid Catalyst for Biodiesel Production

Modern Applied Science ◽

10.5539/mas.v9n7p61 ◽

2015 ◽

Vol 9 (7) ◽

pp. 61 ◽

Cited By ~ 1

Author(s):

Herry Santoso ◽

Christ Michael ◽

Hillman Wira ◽

Maria Inggrid

Keyword(s):

Oleic Acid ◽

Pyrolysis Temperature ◽

Corn Starch ◽

Edible Oils ◽

Raw Materials ◽

Acid Catalyst ◽

Raw Material ◽

Biodiesel Production ◽

Fatty Oil ◽

Heterogeneous Acid Catalyst

Biodiesel can be produced from various oils and fats. Due to possibility of diversion of edible oils from feedstocks to raw materials for biodiesel production, which may lead to food crisis, it is preferable to choosenon-edible oils as raw material for biodiesel production. As a country rich in natural resources, Indonesia has avast amount and variety of non-edible fatty-oil production plants. However, non-edible oils usually have highfree fatty acid (FFA) contents. Oils with high FFA contents cannot be converted directly to biodiesel using aconventional alkaline catalyzed process due to saponification problem. To avoid this problem, the high FFAcontents in the oils must be reduced via esterification process using acid catalyst. The use of homogeneous acidcatalyst in this process can be very corrosive and not environmentally friendly while the use of commerciallyavailable heterogeneous acid catalyst can be very expensive. In this research, a heterogeneous acid catalystsuitable for biodiesel production will be derived from corn starch through pyrolysis followed by sulphonationprocesses. The purpose of this research is to study the effects of pyrolysis temperature and time to the aciddensity of the catalyst and the activity of the catalyst in the esterification of oleic acid using a 22 factorial designwith 3 center points experimental design. It is found that the catalyst obtained from pyrolysis at 400°C for 15hours has the optimum–HSO3 content of 5.9% which corresponds to the highest average conversion of theesterification of oleic acid of 97.45%.

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Different oral sensitivities to and sensations of short-, medium-, and long-chain fatty acids in humans

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00181.2014 ◽

2014 ◽

Vol 307 (3) ◽

pp. G381-G389 ◽

Cited By ~ 19

Author(s):

Cordelia A. Running ◽

Richard D. Mattes

Keyword(s):

Fatty Acids ◽

Oleic Acid ◽

Fatty Acid ◽

Textural Properties ◽

Caproic Acid ◽

Mineral Oil ◽

Particle Size Analysis ◽

Size Analysis ◽

Nonesterified Fatty Acids ◽

Oral Sensitivity

Fatty acids that vary in chain length and degree of unsaturation have different effects on metabolism and human health. As evidence for a “taste” of nonesterified fatty acids (NEFA) accumulates, it may be hypothesized that fatty acid structures will also influence oral sensations. The present study examined oral sensitivity to caproic (C6), lauric (C12), and oleic (C18:1) acids over repeated visits. Analyses were also conducted on textural properties of NEFA emulsions and blank solutions. Oral thresholds for caproic acid were lower compared with oleic acid. Lauric acid thresholds were intermediate but not significantly different from either, likely due to lingering irritating sensations that prevented accurate discrimination. From particle size analysis, larger droplets were observed in blank solutions when mineral oil was used, leading to instability of the emulsion, which was not observed when emulsions contained NEFA or when mineral oil was removed from the blank. Rheological data showed no differences in viscosity among samples except for a slightly higher viscosity with oleic acid concentrations above 58 mM. Thus, texture was unlikely to be the property used to distinguish between the samples. Differences in oral detection and sensation of caproic, lauric, and oleic acids may be due to different properties of the fatty acid alkyl chains.

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Effect of temperature on the frictional forces between polystyrene brushes

Journal of Polymer Science Part B Polymer Physics ◽

10.1002/polb.20701 ◽

2006 ◽

Vol 44 (4) ◽

pp. 649-655 ◽

Cited By ~ 15

Author(s):

Aaron M. Forster ◽

Jimmy W. Mays ◽

S. Michael Kilbey

Keyword(s):

Effect Of Temperature ◽

Frictional Forces

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Use of Carboxylic Acid Ester as Lubricant Component

Oil and Gas technologies ◽

10.32935/1815-2600-2021-135-4-7-9 ◽

2021 ◽

Vol 135 (4) ◽

pp. 7-9

Author(s):

V. A. Zavorotny ◽

◽

I. V. Podkovyrova ◽

Keyword(s):

Molecular Structure ◽

Carboxylic Acid ◽

Viscosity Index ◽

Dicarboxylic Acids ◽

Caproic Acid ◽

High Viscosity ◽

Mineral Oil ◽

Effect Of Temperature ◽

Esterification Reaction ◽

Theoretical Foundations

This paper discusses the use of esters of dicarboxylic acids as components of lubricants. Influence of molecular structure on the properties of ester compositions and the course of the esterification reaction. The theoretical foundations for the production of esters, the synthesis of the ester of caproic acid and butyldiglycol are considered, and the effect of temperature on the esterification process is reflected. Samples of a semi-synthetic oil were prepared, consisting of mineral oil and an ester of various concentrations. The viscosity and density were determined, the viscosity index of the samples under study was calculated. An oil with an optimal concentration of an ester and a high viscosity index was selected.

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