bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the rheological behaviour of synthetic fluids thickened by solid additives
Authors: Vergne P. , Prat P. 
Published: July 2006

AbstractA variety of fluid space lubricants, i.e., synthetic oils thickened by solid additives (particles of PTFE and MoS2), has been developed. These lubricants present a solid‐like behaviour under yield stress, and a strong non‐Newtonian effect during flow. Measurement of the yield stresses revealed an unexpectedly strong interaction between a synthetic hydrocarbon oil and one type of PTFE particle. Furthermore, the substitution of 1 vol.% PTFE particles by MoS2 particles introduced a significant change in the yield stress values. This effect is also apparent in viscosity measurements. These lubricants display, through their rheological behaviour, good ability to replenish contacts over a wide range of temperatures, as shown by measurements taken at −20°C and −60°C.
An evaluation of the gassing tendency under electrothermal stress of some dielectric liquids
Authors: Shrinet V. , Patel M. J. 
Published: July 2006

AbstractIt is known that, under electrical or thermal stress, dielectric liquid produces gas. The performance of oil cooled, insulated, or impregnated electrical equipment such as transformers, cables, or capacitors, is affected by the presence of these small gaseous bubbles, which can give rise to partial discharges and to eventual insulation breakdown. Therefore, the gassing properties of an insulating liquid, i.e. its tendency to absorb or evolve gases, have been recognised as a factor of major importance in characterising dielectric liquids. The transition from gas absorption to gas evolution can occur at different temperatures and electrical stresses for different liquids. The effects of temperature, electrical stress, and ageing on gassing tendency have been well studied. Efforts have also been made to correlate the aromatic content of oil with a gassing tendency. However, such studies are limited to mineral insulating transformer oil.In the present work, an effort has been made to study the gassing characteristics of some common dielectric fluids, including linear alkyl benzene (LAB), silicone oil, and capacitor oil, along with some naphthenic and paraffinic transformer oils.
Properties of naphthalene oligomers polyalkylated with linear 1‐alkenes
Authors: Nemes Sándor , Borbély János , Kovacs Mönika 
Published: July 2006

AbstractStar‐shaped alkylaromatic hydrocarbons consisting of oligomeric naphthalene cores and long straight‐chain alkyl arms have been synthesised using a one‐pot method:magnified imageWhere 1‐alkene is 1‐hexene, 1‐octene, 1‐decene, 1‐dodecene, 1‐tetradecene, 1‐hexadecene, and 1‐octadecene, respectively. Different linear 1‐alkenes with increasing chain length have been reacted with naphthalene oligomers in an identical way, and the properties of the total products compared and related to the chain length of the alkylating normal 1‐alkene. Consequent to this, increases in M̌n, (= 550–1900), viscosity indexes (90–161), pour points (—24 to + 17°C), flash points (210–330°C), and oxidation resistance, could be observed. These products exhibited properties good enough to be suitable for use as lubricant base stocks and/or additives.
Film‐forming tendencies of some base fluids and viscosity modifiers
Authors: Hong Hyun‐Soo , Bair Scott 
Published: July 2006

AbstractThe film‐forming tendencies of selected mineral base oils and synthetic base fluids were investigated with and without conventional GL‐5 additive packages. A pressurised falling‐body viscometer and a concentrated contact simulator were used to measure low‐shear viscosities, central film thicknesses, and traction coefficients. Analysis of the mineral—based oils showed that a paraffinic base oil and a naphthenic base oil had similar film thicknesses, even though the naphthenic base oil has higher pressure‐viscosity coefficients. A very high viscosity index oil gave thinner film thicknesses and lower pressure—viscosity coefficients than the paraffinic or naphthenic base oils. Analysis of the synthetic base fluids showed that a PAO‐4 base fluid gave thicker film thicknesses than an ester base fluid. The analysis of fully‐formulated oils showed that the PAO‐4 oil containing a proprietary polyolefin provided a similar filnz thickness to the PAO‐4 oil containing a more expensive PAO‐100.
Polyglycols as base fluids for environmentally‐friendly lubricants
Authors: van Voorst R. , Alam F. 
Published: July 2006

AbstractPolyglycols are used in a wide range of applications, including lubrication. Many advantageous properties can be obtained for lubricant applications by manipulating the four variables in polyglycol preparation: the initiator, the alkylene oxides, the molecular build‐up, and the mole weight. However, it has long been believed that it would not be possible to combine these properties with a good environmental profile of high biodegradability and low aqueous toxicity. Development work at the authors' laboratory has resulted in polyglycol‐chemistry‐based products that fulfil the application requirements and are also environmentally friendly. Assessment by the Umwelt Bundes Amt has led to a statement of suitability for Blue Angel formulations for two water‐soluble polyglycol grades (ISO 22 and IS0 46). Environmentally‐friendly watersoluble polyglycol base stocks currently includes the range ISO 10 to ISO 100. The development of environmentally friendly water‐insoluble and oil‐soluble polyglycols is under way.
Influence of degradation on the film‐forming properties of polyolester oils
Authors: Yokoyama F. , Spikes H. A. 
Published: July 2006

AbstractThe film thicknesses of two polyolester degraded oils were measured over a wide range of temperatures to investigate the influence of degradation on film‐forming properties. The results have been interpreted in the light of the idea that degradation of an ester lubricant can produce two different types of product which have opposing influences on film‐forming properties. One is the formation of smaller, polar molecules, such as acids, which may result in a decrease in effective pressure—viscosity coefficient. The other is the formation of larger, bulky molecules such as sludge, which result in increased pressure—viscosity coefficient. The effective pressure—viscosity coefficient decrease with degradation of the oil thus is made up of an earlier stage involving a series of reactions, followed in a later stage by an increase.
Base oils of high aromatic, long branched aliphatic pyromellitic esters
Authors: Mirci Liviu E. , Herdan Jean M. 
Published: July 2006

AbstractThe present paper deals with the synthesis of some tetraesters with a mixed structure of pyromellitic dianhydride, and with their characterisation as potential base oils. These esters are made on the basis of a long branched aliphatic alcohol, such as isotridecanol, and an alcohol with aromatic content, such as 2‐phenoxy‐ethanol. The variation of the principal properties as a function of both the length of the aliphatic chain introduced by the aliphatic alcohol, and the aromatic content introduced by the aryl‐alkyl alcohol has been assessed and the potential for viable products with a wide range of viscosity values has been examined. The enhanced aryl content is shown to induce superior thermal behaviour. These products present good test results and, thereby, demonstrate their versatility.
Detailed characterisation of heavy alkylated benzene fluids by multipulse one‐ and two‐dimensional NMR spectroscopy
Authors: Kapur G. S. , Sarpal A. S. , Jain S. K. , Srivastava S. P. , Bhatnagar A. K. 
Published: July 2006

AbstractIn this paper, the results of a characterisation of heavy alkylated benzenes (HAB) using multipulse NMR spectroscopy are presented. Four commercial samples of heavy alkylated benzene have been characterised in detail in terms of various structural parameters, such as percentage aromatic carbon (Ca), degree of aromatic substitution, average alkyl chain length, type of alkyl chain and their proportions. Three of the HAB samples were very similar in structure, whereas, in the fourth, the structures present were entirely different. The latter had an abundance of 2‐phenyl alkane‐type structures, and did not contain methyl substituted tetralin or naphthalene type molecules. The influence of the structures on lubricating oil properties, including viscosity index, pour point, and viscosity, as well as FreonTM floc point, are also discussed.
Research on liquid lubricants for space mechanisms
Authors: Jones William R. , Shogrin Bradley A. , Jansen Mark J. 
Published: July 2006

AbstractFour research areas at the NASA Glenn Research Center in the United States, involving the tribology of space mechanisms, are highlighted. These areas include: soluble boundary lubrication additives for perfluoropolyether liquid lubricants, a Pennzane® dewetting phenomenon, the effect of non‐ozone depleting chemical bearing cleaning processes on bearing lifetimes, and the development of a new class of liquid lubricants based on silahydrocarbons.
Synthesis of dicarboxylic and complex esters by transesterification
Authors: Gryglewicz Stanislaw 
Published: July 2006

AbstractA new method of manufacturing simple dicarboxylic esters and complex esters has been developed. This method is based on a transesterification reaction in the presence of powdered calcium oxide which acts as a catalyst. Commonly accessible raw materials, namely, dimethyl adipate, 2‐ethylhexanol, neopenthyl glycol, and trimethylolpropane were used for the synthesis of the esters. The methanol formed in the transesterification reaction was continuously removed by azeotropic distillation with isooctane. The possibility of producing complex esters with different viscosities and polarities by modification of their chemical structure was studied.
Lubricating properties of rapeseed oils compared to mineral oils under a high load oscillating movement
Authors: Vižintin J. , Arnšek A. , Ploj T. 
Published: July 2006

AbstractThe use of rapeseed‐based lubricating oils has become more widespread in recent years. When these oils have been tested for their tribological properties, some imperfections have been found, especially in conditions of highfrequency and low‐amplitude oscillating movements. In the present work, we compare the tribological properties of commercially available rapeseed‐ and mineral‐based oils, rapeseed and mineral base oils, and these base oils mixed with two additives for improving lubricity. The results are compared for a wide range of contact pressures.
Vegetable and synthetic hydraulic fluids to improve the overall efficiency of a hydrostatic transmission
Authors: Dahlén L. , Isaksson O. 
Published: July 2006

AbstractThe purpose of the investigation reported here was to determine whether or not a hydrostatic transmission can act as an alternative to a conventional one, and, if so, to ascertain to what extent the fluid type contributes to an improvement in the efficiency of the hydrostatic transmission. The results presented in this paper are derived from an experimental field test of the hydrostatic transmission of a belt conveyor. This belt conveyor is one part in an ore‐transport line at LKAB mining company in Kiruna. The hydrostatic transmission replaced a conventional transmission consisting of an electric motor, a belt drive and a gearbox. The hydrostatic transmission was operated using three different hydraulic fluids: Shell Tellus TX 68, a conventional mineral oil; Mobil SHC 526, a synthetic fluid; and Binol Hydrap II, a vegetable fluid. All fluids have the same ISO viscosity grade, VG 68.The measurements on the transmission show a 3% overall efficiency improvement when using vegetable and synthetic hydraulic fluids compared with the mineral oil. The current at the start of the transmission was reduced by a factor of 6, compared to that of the conventional transmission. The installed 110 kW electric motor was replaced with one of 55 kW. The test also showed that a closer study of all operating conditions, and a selection of components suited to the size of the load, can improve the overall efficiency of the hydrostatic transmission.
Aspects of the use of polyoxyalkylene glycols in polymer quenchants
Authors: Thompson R. I. G. , Randles S. J. , Brown M. , Wood J. L. 
Published: July 2006

AbstractSolutions of high molecular‐weight polymers, particularly polyoxyalkylene glycols (PAGs), are used widely in the heat treatment of metals known as ‘quenching’. This is mainly because of the non‐flammable nature of the polymer solution, compared with safety hazards associated with traditional mineral‐oil based quenchants. However, the use of PAG‐based quenchants for some heat treatment processes, particularly for slow cooling speeds, has been limited. This paper describes how, through an understanding of the quenching mechanism, the quench speed of PAG‐based quenchants can be slowed by the use of additives or controlling the conditions of operation. The paper also gives an overview of the experimental measurement of polymer quenching and the factors involved in quenching.
New synthetic ester type base oils with biodegradability potential
Authors: Mirci L. E. , Herdan J. M. , Boran S. 
Published: July 2006

AbstractThe present paper presents the results of some research into the production of synthetic ester oils of mixed structure on the basis of citric acid (2‐hydroxy‐1,2,3 propane tricarboxylic acid) with beneficial tribological properties and potential biodegradability. Two series of unsymmetrical triesters have been synthesised by varying the molar relationship between branched aliphatic alcohols from C4 to C13 along with a special alcohol of a complex aliphaticaromatic structure, namely 2‐(o‐sec‐butyl)phenoxy‐ethanol. Based on this, it has been possible to obtain products with various properties. The introduction of the aromatic function into the structure of these triesters induces interesting features, and the natural source of the citric acid holds potential for having good ecological characteristics, which are intended to be the subject of further research.
Total vegetable oil greases
Authors: Gangule N. G. , Dwivedi M. C. 
Published: July 2006

AbstractA grease has two major constituents, namely, a lubricant, that performs the function of lubrication; and a gellant, that provides a solid continuous phase, occludes the lubricant, and gives apparent physical structure to the grease. Generally, the gellant is 5–30% and the lubricant 65–90%, additives and fillers making up the rest. In conventional greases, the gellant is a vegetable oil soap, and the lubricant is a liquid oil of petroleum origin or is a synthetic. Such greases have limited biodegradability, because the major constituent, i.e., the lubricant, is normally not biodegradable.In total vegetable oil grease, both the gellant and the lubricant are derived from vegetable oils, giving a grease of potentially high eco‐compatibility. Esters, dibasic acid esters, and alkylated esters of vegetable oil are known to be high‐quality lubricants. These can be used with soap stocks prepared from vegetable oils to give a grease of total vegetable oil origin.The vegetable‐oil based lubricants and soaps are prepared separately and combined in appropriate proportions to give a grease of the required specifications. Alternatively, esterification and saponification can be carried out simultaneously to give a grease of the desired specifications, where an alkali will be the catalyst for esterification, and reactant for saponification. In this paper, the process parameters, and kinetics of these simultaneous reactions are discussed. The results of experimental evaluation of some of these greases are also presented.
Phosphate esters with a complex structure of an alkyl‐aryl type considered as base oils
Authors: Mirci Liviu E. , Herdan Jean M. , Ilia Gheorghe 
Published: July 2006

AbstractThis paper presents results of work carried out to produce phosphate esters of the alkyl‐aryl type. Three new triesters of mixed structure have been synthesised using a special alcohol with an aryl content, e.g., 2‐phenoxy ethanol, and a very long branched alcohol, e.g., isotridecanol. The influence of the aryl content and the effect of the long aliphatic chain on the main tribological properties have been investigated.
Composition and oxidative stability of hydro‐cracked base oils and comparison with a PAO
Authors: Cerny Jaroslav , Pospisil Milan , Sebor Gustav 
Published: July 2006

AbstractThe oxidative stability of nine hydrocracked base oils from seven producers and a PAO was compared using the standard IP 48 test. After a comprehensive characterisation of the oils, an evaluation of oxidative stability was carried out by measuring some common oil parameters, such as viscosity characteristics, carbon residue, pentane insolubles, and acid number. Additionally, the compound‐class composition of the fresh and oxidised oils was determined, and an FTIR spectroscopic analysis was carried out.The oxidative stability of the hydrocracked oils was largely affected by the sulphur and aromatic hydrocarbon concentration in the oils. Oils with an increased sulphur content (above 80 ppm) had better oxidative stability than oils with a low sulphur content (20 ppm and lower), and there was a relatively large variability in the stability of the oils depending on the sulphur concentration. The oxidative stability of most of the hydrocracked oils with a low sulphur content was similar, and matched somewhat the stability of the polyalphaolefin.
Structural characteristics and mechanism of action of antioxidant anticorrosive additives for perfluoropolyalkylether fluids
Authors: Wang Daxi , Ying Feng 
Published: July 2006

AbstractThe combination energies of perfluoropolyalkyletherphenylamide (PFPEA) with perfluoropolyalkylether oxygen radicals (RfO) and with Fe atoms have been calculated by quantum chemical methods. The values are ‐417.33 and ‐105.02 kJ/mol, respectively. The structural characteristics and the mechanism of action of an antioxidant anticorrosive additive have been explored. It was found that the highest occupied molecular orbital (HOMO) of the additive is a π molecular orbital and it has the properties of a typical electron donor. The HOMO of the PFPEA additive reacts with the lowest unoccupied molecular orbital (LUMO) of an Fe atom and forms a coordinate bond and chemically adsorbed film on the metal surface. The film inhibits catalytic degradation and protects the metal surface. The additive is also capable of accepting the electron of RfO. The RfO radical combines automatically with the C7 atom of the benzene ring to terminate the RfO decomposition reaction. The PFPEA additive has been synthesized and analysed by UV and IR. Measurement of antioxidant anticorrosive properties indicates that, in the presence of the synthesised additive, the weight loss of a perfluoropolyether lubricant is reduced by about 7 times and the degradation temperature is increased by about 19°C compared with the base oil without the additive. The experimental results are consistent with the conclusions from the theoretical study.
Tribological behaviour of three phosphate esters containing the benzotriazole group as additives in rapeseed oil
Authors: Li Jiusheng , Ren Tianhui , Zhang Yanyan , Wang Dapu , Liu Weimin 
Published: July 2006

AbstractSince the 1970s more attention has been paid to biodegradable lubricants as a way of reducing the pollution caused by lubricants with a mineral oil base. This concern has promoted the use of vegetable oils as alternative base oils. This paper reports on a study of the effect of phosphate esters containing the benzotriazole group as additives in rapeseed oil (RSO), tests being carried out using a standard four‐ball tester. The results show that these additives produce good antiwear performance and load‐carrying capacity compared with RSO alone. Surface analysis of the worn halls was carried out using X‐ray photoelectron spectroscopy. The tribological mechanism is discussed on the basis of the experimental results.
The influence of some additives on the lubricating properties of semi‐synthetic ester oils
Authors: Szalajko Urszula , Fiszer Stefania , Lipa Barbara 
Published: July 2006

AbstractThis article presents research on the lubricating properties of semi‐synthetic oils, made as compositions of mineral oil and esters. The esters were synthesized from acid substrates from the oxidation of paraffins. The last non‐seizure load (Pn), the weld point (Pz), the load wear index (Ih), and the limiting wear load (Goz) were measured, and the effects of additives or mixtures of additives were investigated by their effects on these parameters. It was found that the efficiency of the additives depended on their chemical characteristics and concentration, and also on the chemical nature of the ester component of the semi‐synthetic oils.
The influence of chemical structure on the physical properties and antioxidant response of hydrocracked base stocks and polyalphaolefins
Authors: Gatto V. J. , Grina M. A. , Tat T. L. , Ryan H. T. 
Published: July 2006

AbstractThis study was conducted to determine the effect of hydrocracked base stock chemical composition on lubricant properties, oxidation performance, and antioxidant additive response. Fifteen hydrocracked base stocks and polyalphaolefins were analysed by mass spectrometry for paraffinics, and single‐, double‐, and multi‐ring naphthenics. Low levels of aromatics were confirmed in all the base oils. A linear relationship was found between certain naphthenic structures in the base stocks and properties, such as viscosity index, aniline point, and volatility. Additivated versions of the base stocks were also screened in the rotary bomb oxidation test (ASTM D 2272) and the thin‐film oxygen uptake test (ASTM D 4742). A relationship between the types of naphthenic structures in the additivated base stocks and oxidative stability was found. Base oils containing low levels of condensed multi‐ring naphthenic structures exhibited superior oxidation performance, lower volatility, and poorer solvency. Furthermore, antioxidant structure had a profound effect on oxidative stability as the level of multi‐ring naphthenic structures in the base oils decreased. These results suggest that deeper knowledge of chemical composition could help in selecting base stocks and additives to meet future product specifications.
Production kinetics of the esterification of a polyol
Authors: Patil T. A. , Sen T. K. , Chattopadhyay S. 
Published: July 2006

AbstractTailor‐made esters are becoming more widely used as either synthetic base stocks or performance additives for producing, for example, premium‐grade synthetic or semi‐synthetic speciality greases, aviation lubricants, or metal‐working fluids. The present work, using a laboratory batch autoclave to evaluate the kinetic parameters, considers the kinetics of a typical non‐catalytic esterification of a suitable polyol at elevated temperatures (190‐220°C) and corresponding vapour pressure. The proposed rate equation represents satisfactorily the progress of the reaction.
Influence of abrading particle size on the wear performance of various polyamides
Authors: Rajesh J. John , Bijwe J. , Tewari U. S. 
Published: July 2006

AbstractVarious polyamides (PAs) containing different CONH2/CH2 ratios were selected for abrasive wear studies. Eleven types of silicon carbide (SiC) papers varying in particle size (10–175 μm) were selected as abrading counterfaces. The wear performance under single‐pass conditions indicated that the selected PAs did not show a size effect, in contrast to the case of metals and some other polymers. Wear rates were of the order of 2–17 × 10−11 m3/Nm. Scanning electron micrographs of some of the worn papers indicated correlations between wear and the size and number of wear debris particles and the amount of material transferred to the papers.