bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tris(2‐octyldodecyl)cyclopentane, a low volatility, wide liquid range, hydrocarbon fluid
Authors: Veier C. G. , Casserly E. W. , Gunsel S. 
Published: July 2006

AbstractTris(2–octyldodecyl)cyclopentane, prepared by the hydrogenation of the product of alkylation of cyclopentadiene by 2–octyldodecanol, is a wide liquid range hydrocarbon fluid (pour point, −57°C; vapour pressure at 20 °C, 1 × 10−12). This new fluid compares favourably with other hydrocarbons and per fluoropolyethers (PFPAEs) in properties useful for vacuum applications in which low temperature fluidity and low volatility are important properties. It is half the density of PFPAE and exhibits inhibitable oxidation properties similar to other hydrocarbons. The pressure‐viscosity coefficient is similar to those of PAOs and PFPAEs.
Improvement of silahydrocarbon performance with additives
Authors: Thomas S. G. , Campbell D. G. , Hsu C. J. 
Published: July 2006

AbstractIn order for silahydrocarbons to qualify, for use in a broad range of applications (automotive, aerospace, and industrial), the formulated fluid must have good oxidative stability and lubricity.This paper compares the response of a silahydrocarbon, a synthetic hydrocarbon, and a mineral oil to various antiwear and antioxidant additives. A merit rating system is described: it provides a relative ranking of the different formulated fluids according to performance.
Rheological and tribological characterisation of six wet lubricants for space
Authors: Sicre J. , Berthier Y. , Flamand L. , Reynaud P. , Vergne P. , Godet M. 
Published: July 2006

AbstractDry lubricants are often used in space because of their excellent behaviour in a vacuum and their thermal stability. However, mechanisms which are heavily loaded, with a high sliding rate, a long life span, or needing a stable friction coefficient cannot use this kind of product. They can be replaced by wet lubricants specially developed for vacuum applications. Such lubricants have a low vapour pressure in order to minimise outgassing losses and avoid contamination.Since European experience in the field of wet lubrication in space is rather limited, the French Space Agency CNES, with the help of the LMC (Laboratoire de Mécanique des Contacts ‐ Contact Mechanics Laboratory), is currently characterising several wet lubricants for use in space applications.The selected lubricants were tested on a vacuum friction test bench which allows the main contact parameters to be controlled: speed, load, and kinematics. The bench is equipped with vacuum facilities and, since it runs under air, neutral gas, or vacuum, it can be used to study the effects of atmosphere. Variations of physical properties (viscosity) versus temperature (−60°C to 100°) and pressure (from atmospheric pressure to 500 MPa) were studied for all the lubricants tested, and these characteristics take into account in the analysis of the tribological test results.This paper briefly lists the characteristics of a space environment (vacuum, microgravity, etc.) and their consequences for lubrication. It describes the equipment used and the tribological and rheological test results obtained on six wet lubricants (three oils and three greases). It also contains conclusions in terms of recommendations about the use of such lubricants.
Structure–property relationships of model chlorstrifluoroethylene oligomer compounds: Thermal stability
Authors: Snyder Carl E. , Gschwender Lois J. , Fultz George W. , Paciorek Kazimiera R. L. , Kratzer Reinhold 
Published: July 2006

AbstractLow molecular weight chlorotrifluoroethylene (CTFE) oligomers have been the base fluid for an extensive DoD research and development programme for nonflammable hydraulic fluids, compatible elastomeric seals, components, and systems. To gain a more fundamental understanding of the effect of the specific isomers and other components of commercial CTFE fluids on the important fluid properties, model compounds were synthesised and their physical and chemical properties were determined. Thermal stability, in the presence of typical hardware system metals, is one of the more important properties and is discussed in relation to molecular structure. Two Microscale evaluation techniques were devised and validated. Optimum thermal stability is observed when the chlorines in the molecules are positioned as far apart as possible. In general, it was found that the compounds with larger amounts of chlorine were less stable and the positioning of the chlorine in the molecule had a lesser, but measurable effect.
The tribological study of S‐(1H‐Benzotriazol‐1‐yl) methyl N,N‐dialkyldithiocarbamates as additives in synthetic lubricants
Authors: Ren Tianhui , Xue Qunji , Wang Hanqing 
Published: July 2006

AbstractThe load‐carrying capacity, wear, and friction properties of four S‐(1 H‐Benzotriazol‐1‐yl)methyl N,N‐dialkyldithiocarbamates added to a synthetic lubricant (diester) were evaluated using a four‐ball test machine and an Optimal SRV tester. The results indicate that these compounds added to the diester possess good load‐carrying capacities and antiwear properties. The rubbed surfaces were investigated using X‐ray photoelectron spectroscopy (XPS) analysis and the antiwear mechanism is discussed.
Oils with low environmental impact for modern combustion engines
Authors: Mattei L. , Pacor P. , Piccone A. 
Published: July 2006

AbstractExperimental work was carried out to evaluate the influence of synthetic lubricants on engine performances and their consequences for the environment. The effect of the rheological and compositional characteristics of lubricants on fuel efficiency, oil consumption, thermo‐oxidative stability, and wear was investigated. To this purpose, both conventional tests normally used for assessing oil quality according to European specifications and non‐conventional/in house tests were used. Among the latter, engine oil consumption, minimum oil film thickness, bearing wear, valve train wear, thermo‐oxidative stability, and high temperature deposit tests were included.Preliminary conclusions show that a 5W‐30full synthetic oil has a lower impact on the environment than a current IOW‐40 part synthetic‘European’oil and is a better compromise between fuel efficiency and oil consumption.A field test programme is in progress in order to assess general engine performance, especially oil consumption and the effect of oil on catalyst efficiency.
The origins of synthetic lubricants: The work of Hermann Zorn in Germany part 1 basic studies of lubricants and the polymerisation of olefins
Authors: Jantzen Eilhard 
Published: July 2006

AbstractThis paper has been written to commemorate this January the 100th anniversary of the birth of Hermann Zorn, whose research led at the beginning of the 1930s to the first synthetic oils being produced in Germany. This development work, started in 1926 and pursued up until 1944, can be seen to have taken place in four successive stages:
basic research and synthesis of hydrocarbons in pursuit of an‘ideal’lubricant,
work to develop synthetic lubricants on the basis of olefins,
research on and development of additives to improve the performance of synthetic lubricants,
synthesis, research into structure, and process development of esters for special lubricants with advanced oxidative stability and good low‐temperature behaviour.
The first part of this survey of his work describes his basic research on lubricants and his work on the polymerisation of olefins. The second part will look at his work on additives and ester oils and their application in aviation.
The wear behaviour of polymer composite gears
Authors: Mao K. , Hooke C. J. , Walton D. 
Published: July 2006

AbstractIn order to examine the wear of polymer composite gears, a test facility has been developed which has enabled the wear of gear trains to be measured continuously during gear operation. Brief details of the method are given. The purpose of this paper is to report some of the results obtained from this facility and, in particular, to discuss the effect of temperature on the wear of acetal gears.
Self‐diffusion of oil in lubricating greases by NMR
Authors: Hermansson Mathias , Johansson Erik , Jansson Mikael 
Published: July 2006

AbstractSelf‐diffusion of base oil in six model lubricating greases and in the base oils themselves was measured using pulsed‐field gradient nucleic magnetic resonance (NMR) at 23, 40, 70, and 90°C. Three of the greases were based on naphthenic mineral oils, and three were based on synthetic polyalphaolefin oils. Soaps of 12‐hydroxy stearic acid were used as thickener agents in all six greases. The purpose of the investigation using NMR was to see if structure varies with temperature, and if NMR is a viable method for structure determination.The ratio between the diffusion coefficient of the base oil in the grease and the neat base oil in itself was evaluated as a function of temperature. This ratio was taken as a direct indicator of the obstruction effect that the thickener has on the oil.The thickener showed a stronger obstruction effect on the base oil in the synthetic grease than in the mineral‐based grease. This was related to the soap content, which, for these greases, is roughly twice as high in the synthetic greases as in the mineral ones. The obstruction effect was constant in the temperature range 40–90°C for mineral‐ as well as synthetic‐based greases. NMR was judged to be a promising method for investigating how the gellant affects the diffusion coefficient of oil in a lubricating grease.
An evaluation of the influence of cylinder liner finish and synthetic lubricating oil on exhaust hydrocarbon species from an SI engine
Authors: Willcock M. , Tidmarsh D. H. , Foss P. 
Published: July 2006

AbstractAs part of the continuing attempt to reduce emissions from automotive engines this paper investigates the effect of cylinder lubrication on hydrocarbon emissions, and shows that the effect of a synthetic oil on total emissions is insignificant. However, more positive results have been obtained using cylinder surface finish to control oil layers in the combustion chamber. Studies of the hydrocarbon species in the emissions showed significant differences due to surface finish profiles.
Modified TMP esters as multifunctional additives in metalworking fluids
Authors: Mathiesen T. 
Published: July 2006

AbstractThis paper looks at newly developed trimethylolpropane (TMP) esters, which have multifunctional properties as additives in aqueous metalworking fluids. Such TMP esters can replace the previous monofunctional esters, which provided only lubrication.New TMP esters are obtained by chemical modification of traditional TMP esters, and provide the functions of lubrication, corrosion protection, and co‐emulsification in one product. The paper looks at the chemistry of these esters, and their properties. Some experimental products are also examined.
Synthetics versus vegetable oils: Applications, options, and performance
Authors: Miles P. 
Published: July 2006

AbstractEnvironmental concerns have brought forward vegetable oils as alternatives to more expensive synthetic lubricant base stocks, in moderate operating conditions. The contents of various acids, such as oleic and linoleum, can be changed by selective breeding to produce more desirable lubricating properties and less oxidation vulnerability.Different tests are needed for such lubricants, and the Baader test has been modified to show the ageing stability of rapeseed oil raffinate, TMP trioleate, dioctyl adipate, and HOSO. Such oils can also be modified with additive packages.
Assessment of ep additives for water‐miscible metalworking fluids
Authors: Mandakovic R. 
Published: July 2006

AbstractThis paper presents a short overview of the background to EP additives and their operating mechanism in relation to temperature activation, in the formulation of water‐miscible metal working fluids.The physical and chemical properties, determined using standard laboratory equipment, and dynamic tests, of different formulations of water‐miscible metal working fluids are given. The main work reported here was to compare the EP performance of available commercial additives, looking particularly at commercial variations of phosphate esters as replacements for chlorparaffins. The paper concludes that the ‘tapping and drilling’ test, which is a relatively good simulation of practical conditions in metalworking operations, can be successfully used as a way of selecting the appropriate EP additives, and for formulation of the concentrate.
A study of the role of solid lubricant and fibrous reinforcement in modifying the wear performance of polyethersulphone
Authors: Bijwe J. , Rajesh J. John , Jeyakumar A. , Ghosh A. K. 
Published: July 2006

AbstractHigh‐temperature polymers are generally preferred for those tribology applications where cost is secondary and performance is the primary consideration. Since frictional heat dissipation limits the usefulness of polymers because of their poor thermal conductivity, high‐temperature polymers are preferred in applications which have harsh operating conditions. In this paper, a high‐temperature polymer, polyethersulphone (PES), was selected for some adhesive wear studies, along with two PES composites containing 18% glass‐fibre (GF) reinforcement and two solid lubricants, i.e., PTFE and MoS2 (2% each). Adhesive wear studies of these materials on two pin‐on‐disc machines indicated that neat PES was not a good tribo‐material. However, incorporation of GF and solid lubricants enhanced the wear performance by an order of two. PTFE was found to behave better than MoS2. However, after long sliding duration both the lubricants performed almost equally well. The topography of the surface of the pins and the disc was studied using SEM to investigate the wear mechanisms.
Preliminary studies of the influence of cryo‐treatment on the mechanical and tribological properties of ptfe and composites
Authors: Indumathi J. , Bijwe Jayashree , Ghosh A. K. 
Published: July 2006

AbstractCryogenic treatment of polytetrafluoroethylene (PTFE) has proved beneficial in improving the abrasive wear resistance of several polymers, and it was thus assessed in an adhesive wear mode, as well. Preliminary investigations on the effect of cryogenic treatment on the tribological properties, in adhesive wear mode, and mechanical properties of neat PTFE and it composites filled with bronze or short glass fibres (GF) were carried out. It was found that, although the improvement in the wear and friction performance of neat PTFE and a GF + PTFE composite was significant, no such positive effect was observed for the bronze + PTFE composite. On the contrary, this composite showed a deterioration in performance.The reason behind the improvement in the tribological behaviour of neat PTFE and the GF + PTFE composite could not be clearly understood. However, it was confirmed that, if the treatment adversely affected the mechanical properties, then the tribological performance also deteriorated. An examination of the worn surface of the material and the counterface disc using a scanning electron microscope revealed changes in the microstructure due to the treatment. It was also confirmed from these SEM studies that the compatibility of bronze and PTFE was very poor, which led to poor performance of the composite both in the untreated and the cryo‐treated form. Further detailed investigation and analysis of various materials and composites, however, are necessary to establish the utility of this technique.
Viscosity–pressure–temperature behaviour of mineral and synthetic oils
Authors: Gold P. W. , Schmidt A. , Dicke H. , Loos J. , Assmann C. 
Published: July 2006

AbstractA new high‐pressure viscometer that can measure viscosity at pressures up to 0.8 GPa has been developed in the authors' laboratory. The ‘modulus equation’ has been used to compare the behaviour of mineral and synthetic lubricants. Among the oils investigated there was one ester that biodegraded rapidly both before and after ageing in a long‐term test‐rig operation. To facilitate a comparison or application of the results to other oils, an analysis of the correlation between the viscosity—pressure coefficient and the kinematic viscosity measured at atmospheric pressure has been provided. A prediction of lubricant film thickness based on high‐pressure viscosity data is compared with film thickness measurements in a roller bearing.
A tribological study of an S–P–N containing additive in polyalphaolefin
Authors: Li Jiusheng , Ren Tianhui , Wang Dapu , Liu Weimin , Xue Qunji 
Published: July 2006

AbstractThe load‐carrying capacity, antiwear, and friction reduction properties of a novel S—P—N additive (BMDDP) added to a synthetic lubricant, polyalphaolefin (PAO), were evaluated using a four‐ball test machine. The results were compared with those of a commercial S—P—N additive (T307), and show that BMDDP is an excellent extreme pressure and antiwear additive in polyalphaolefin, similar to T307. The rubbed surfaces were investigated using X‐ray photoelectron spectroscopy, and the antiwear mechanism is discussed.
Lubricating oils based on chemically modified vegetable oils
Authors: Bírová A. , Pavlovičová A. , Cvenroš J. 
Published: July 2006

AbstractVegetable oils are a type of easily biodegradable ester‐type lubricant derived from renewable resources. Their importance, from the environmental view‐point, is evident, especially in loss lubrication, hydraulic systems with increased risk of damage, etc. They are characterised by good lubricity and good anticorrosion and temprature‐viscosity properties. Some disadvantages, particularly low thermal oxidation stability and poor cold flow behaviour, can be mitigated by structural modifications. In this study, possible substitutions of the alcohal part of triacylglycerols as well as changes in acyl unsaturated chains are discussed. Attention is paid particularly to the epoxidising of double bonds in acyls resulting in the formation of oxirane rings. By opening these in the presence of hydrogen donors, it is possible to obtain new derivatives and polyfunctional compounds that are acceptable as environmentally friendly lubricants.
Benefits of synthetic lubricants in industrial applications
Authors: Murphy W. R. , Blain D. A. , Galiano‐Roth A. S. , Galvin P. A. 
Published: July 2006

AbstractSynthetic lubricants were originally developed and used for applications where petroleum products were inadequate (e.g., at extremely high and low temperatures, under extreme wear conditions) or where special characteristics, such as long life, improved equipment efficiency, or non‐flammability, were needed. However, the use of synthetic lubricants is not restricted to special applications, but is also useful when they can provide cost efficiency in areas such as machine reliability, oil life, energy consumption, biodegradability, and safety. Among many successful applications, typical cases where synthetic fluids have clear advantages over conventional lubricants include: high‐temperature lubricants for plastic calenders (significant lengthening of oil‐change intervals, fewer machine shutdowns): worm gear drives under severe service conditions (increase in efficiency, lower operating temperatures); air compressors (elimination of combustible petroleum residues); hydraulic fluid in fire‐resistant applications (mining equipment, pressure casting machines, steam turbine control systems); and high‐speed greased bearings (reduced friction losses).The benefits of synthetic lubricant base stocks are derived not only from their basic molecular structures but also from the absence of harmful molecular species often unavoidably present in conventional mineral oils in small, but significant, concentrations. There are very many compounds in crude oil, and while many, or most, of the harmful ones are removed or upgraded by refining, depending on the methods used, a significant number will inevitably remain in lubricating oil stocks, whether solvent‐ or hydrotreated. Thus, conventional oils comprise a wide variety of molecular species, many of which are not well characterised. In contrast, synthetic products normally are produced by chemical reactions of very pure, small molecules in which pressure, tempesutuse, und the ratio of reactants cun he curefully controlled. Frequently, the synthesis o j the reaction up to the desised end product includes severul steps, each of which necessitutes a pusifcution of the intermediute psoducts. It is this resulting ji‐eedom jhom undesisuhle compounds that gives synthetic lubricants their distinctiiie characteristics. It also contrihutes to their higher cost, compased to mineral oils, the oiserall cost of u synthetic product being the sum of the costs of the raw materials und the costs of the individual reuction steps.It is estimuted thut approximutely 80% of the worldwide synthetic luhsicants market is repsesented by three generic groups: polyulphaolejins (∼45%), organic esteia (∼25%), and polyglycols (∼10%). Of the remaining synthetic luhricunts, phosphate esters and polyhirtenes make up probably the largest sules volumes, with about S% each in total. This paper. provides an overview of the types, characteristics, uses, und udwrztages of synthetic lubricants, based on these major technology categories.
Recent trends in environmentally friendly lubricants
Authors: Hörner Dietrich 
Published: July 2006

AbstractMany of the lubricants used in the world today cause environmental pollution through total‐loss applications, spillage, evaporation, and in other ways. To reduce this environmental damage, new lubricants that are rapidly biodegradable and ecologically non‐toxic have started to be developed and marketed. This paper discusses the introduction of environmentally friendly lubricants and their constituents, with particular emphasis on their environmental benefits, applications, the limits to their use, their technical performance characteristics, and relative cost aspects; many of these lubricants are based on vegetable oils and esters. Comparisons are also made in the paper with conventional mineral‐oil based materials.
A study of the tribological behaviour of dialkyldithiophosphate esters as additives in rape seed oil
Authors: Li Jiusheng , Zhang Yanyan , Ren Tianhui , Liu Weimin , Wang Dapu 
Published: July 2006

AbstractZinc dialkyldithiophosphates (ZDDP) cannot be used as additives in biodegradable lubricants because of their zinc content. In investigating substitutes for ZDDP, dialkyldithiophosphate esters have been synthesised, and their tribological behaviour as additives in rape seed oil has been evaluated using a four‐ball friction and wear tester and compared with that of ZDDP. The results show that these additives have better antiwear properties and load‐carrying capacity than rape seed oil alone. The morphologies and the elemental chemical states on the worn surfaces of the lubricated steel balls of the tester were examined using X‐ray photoelectron spectroscopy and scanning electron microscopy. The tribological mechanism is discussed on the basis of the experimental results.
The friction and wear of different polymers under high‐load conditions
Authors: De Baets P. , Ost W. , Samyn P. , Schoukens G. , Van Parys F. 
Published: July 2006

AbstractEngineering polymers are increasingly being used as self‐lubricating materials in demanding high‐load applications. In this study, a comparison has been made of the tribological behaviour under high‐load conditions of two grades of polyamide and polyethylene terephthalate as well as polyacetal. Large‐scale testing is used to reduce edge effects. It has been found that the two grades of polyamide and pure polyethylene terephthalate are prone to stick—slip, while internally lubricated polyethylene terephthalate and polyacetal show low friction and wear and no stick—slip.