bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detailed characterisation of polyalphaolefins and their branched structures using multi‐pulse NMR techniques
Authors: Kapur G. S. , Sarpal A. S. , Sarin R. , Jain S. K. , Srivastava S. P. , Bhatnagar A. K. 
Published: July 2006

AbstractThe present work describes some structural investigations carried out on commercial and laboratory synthesised polyalphaolefin (PAO) samples. A number of structures having different branched groups along the chain have been identified in the hydrogenated dimer product of 1‐decene, using multi‐pulse 13C‐NMR DEPT techniques. These branched structures have been further confirmed by correlating methyl and methine group resonance in the 13C‐NMR spectra, using a CALMOD computer program. An insight into the molecular mobility and dynamics of various structures has been obtained through spin lattice relaxation measurement. The study aims to provide a better understanding of the structure—performance relationships in PAOs. A probable mechanism of oligomerisation responsible for the formation of the identified structures is proposed.
Functional fluids and additives based on vegetable oils and natural products: A review of the potential
Authors: Patil A. S. , Pattanshetti V. A. , Dwivedi M. C. 
Published: July 2006

AbstractFunctional fluids and additives normally have an ‘R — P’ type of linear chemical structure, where ‘R’ is a linear or isoalkyl chain, and ‘P’ is a mild‐to‐strong polar group. For functional fluids ‘P’ is non‐polar to mildly polar, and for additive molecules it is mild to highly polar. The additive activity depends upon the degree of polarity.Some natural products also have predominantly linear structures in their constituents. Many of these are available in commercial quantities and some even occur as waste. These could be used for the synthesis of functional fluids and additives. This paper covers three groups of such natural products. These are non‐edible vegetable oils, terpenes, and cashew nut shell liquid. The synthesis and characteristics of functional fluids and a variety of possible additives are described. Besides being an alternative non‐petroleum resource, such products have a high degree of biodegradability, as they are derivatives of natural products.
Influence of load and lubricants on EHD film thickness and rolling‐contact fatigue lives of AISI 52100 steel balls
Authors: Fernández J. E. , Luque P. , Cuervo D. G. 
Published: July 2006

AbstractThis work has evaluated the influence of load and type of lubricant on the thickness of the elastohydrodynamic (EHD) film and the rolling‐contact fatigue lives of AISI 52100 steel balls. The lubricants studied have various viscosities and included two mineral oils and five synthetic oils from three families. Firstly, the central film thickness was determined in order to predict the lubrication regime. The stress—number of cycles fatigue curves were then calculated by means of Weibull plots, and the fatigue mechanism was evaluated.The test machine used for the analysis was a Seta‐Shell 1980 four‐ball EP lubricant tester. The 12.7 mm diameter test balls were made from a single batch of carbon‐vacuum‐deoxidised AISI 52100 steel with hardness RC65.Elastohydrodynamic film thickness estimation was carried out using pressure—viscosity coefficients (a). In this study, to calculate (X), a new interferometric technique, ultrathin film interferometry, was employed to measure the film thickness. A practical method was developed for evaluating EHD, mixed film, and solid lubrication processes. Micrographic mapping and energy dispersive spectroscopy (EDS) were used to analyse the rolling track of the test balls.
Accumulation of lead in ester‐based engine oils
Authors: Baumann W. , Reiter K. , Zeiner W. 
Published: July 2006

AbstractSynthetic esters are widely used as base‐oil components in top‐tier crankcase lubricant formulations. In combination with synthetic hydrocarbons, an ester content of between 10 and 50 wt.% is common. Only a few engine oils with an ester content above 85 wt.% have been introduced on to the market as yet. The use of such engine oils is advantageous, especially in environmentally sensitive areas, in terms of volatility, particle emissions, and biodegradability.Some older types of heavy‐duty diesel engine continue to be run in vehicles and in machinery in the construction industry, and in such engines a higher lead content has been detected when ester‐based engine oils have been used. It has been found that lead is extracted from the bearings and accumulates ultimately in the engine oil during operation. Consequently, the development of a suitable inhibitor system has been initiated to improve engine and bearing protection. To determine the effectiveness of the new inhibitors, a suitable test method had to be found.Using a test method based on the Petter WI (CEC L‐02‐A‐78) test engine, the present paper summarises the results of tests on an inhibitor system to prevent lead extraction from bearings The metal contents reported in this paper were determined by ion conductive plasma atomic emission spectrometry.
Advances in US Air Force hydraulic fluids
Authors: Gschwender Lois J. , Snyder Carl E. , Sharma Shashi K. , Flanagan Stephanie R. 
Published: July 2006

AbstractThe US Air Force Wright Laboratory's Materials Directorate has been involved with the development and transition of advanced fluids and lubricants since the 1950s. The driving force for the development of new hydraulic fluids has primarily been and still is, improved fire resistance, although biodegradability and low toxicity have become increasingly important. This paper briefly traces the use of military aircraft hydraulic fluids from the beginning to the current state‐of‐the‐art.
Development of Al‐base lubricating grease thickeners
Authors: Dudás C. S. , Toth J. , Vuk A. 
Published: July 2006

AbstractIn this paper are presented the results of work on the development of poly‐oxo–aluminium acylates that are dissolved in synthetic lubricants, polyalphaolefins (PAOs) andpolyisobutenes (PIBs), and one pharmaceutical mineral oil in order to produce a range of greases that can be food‐grade, and have chemical stability.The method of synthesis is described, together with the results using different base oils (two different PAOs, four different polybutenes, and a pharmaceutical grade IS0 VG 46 white mineral oil. These greases are characterised here in terms of their mechanical stability and physical properties. As well as being of food grade, these greases are also shown to be chemically stable.
Lubricating properties of rapeseed‐based oils
Authors: Arnšek A. , Vižintin J. 
Published: July 2006

AbstractThree commercially available hydraulic/transmission lubricants based on rapeseed oil have been investigated for their lubricating properties. The coefficient of friction, scuffing‐load capacity, and pitting resistance were evaluated, and the results compared with a corresponding commercial mineral‐based oil.The results showed in general a substantially lower coefficient of friction and better pitting resistance for rapeseed‐based oils than for the mineral oil. Scuffing load capacity was, with one exception, the same for all oils. As a result of lower shear stresses during contact, and a higher viscosity index, the temperatures in the gearbox were lower for the rapeseed oils tested than for the mineral oil. Insufficient antiwear behaviour at high loads was found to be a major drawback of these vegetable oils.
Producing multigrade lubricating greases from animal and vegetable fat by‐products
Authors: El‐Adly R. A. 
Published: July 2006

AbstractThis paper reports on some work concerned with the synthesis and characterisation of three lubricating greases based on animal bone fat, cottonseed soapstock, and a mixture of them both. The physico‐chemical properties of these fats were established and showed them to be good thickeners in the preparation of different types of greases. It was shown that the growth of the soap structure and grease consistency depend on the type of fat as well as on the viscosity of the lubricating oil in the grease formulation. The greases so synthesised were assessed in accordance with standard NLGI grades and Egyptian standards. Their rheological and thermal behaviour was studied, which revealed that the synthesised greases have significant yield stress at normal operating temperature and good flow properties. It was concluded that the above mentioned fat by‐products are suitable for producing greases.
Synthesis and testing of ester lubricants for use as R‐134a refrigerants
Authors: Gryglewicz S. , Beran E. 
Published: July 2006

AbstractThe aim of the present work was to produce inexpensive synthetic lubricants, compatible with R‐134a, using waste carboxylic acids as the starting point. After initial synthesisation of some candidate materials, the suitability of the synthesised products was first evaluated by their chemical and physical properties including thermostability. Two ester bases were selected for further testing — a pentaerythritol esterified with monocarboxylic acids, and a polyalkyleneglycol similarly esterified with monocarboxylic acids C4—C6. The oil bases selected were tested for their corrosion effect on metals. The pentaerythritol ester offered the most advantageous properties in these tests. The results of the laboratory tests have been corroborated by trials conducted on real refrigerating compressor systems. In addition, the synthesis of base oils by methyl ester transesterification in the presence of basic catalysts has been examined.
Synthesis and testing of some new antioxidant and anticorrosion additives with potential for use in turbine aviation oils
Authors: Hassan H. M. , Youssif M. M. , Khalil A. M. , Youssif E. H. E. 
Published: July 2006

AbstractThis paper reports on work by the authors to develop a series of heterocyclic compounds for use in turbine aviation oils as antioxidant and anticorrosion additives. First, the new compounds were synthesised, and twenty‐eight candidate additives were developed. These were tested for their antioxidant and anticorrosion properties, and from these results three were found to exhibit better behaviour than the others. These three were then tested against DODPA, an existing aviation fluid additive, and were found to offer comparable behaviour in initial tests.
Environmentally adapted lubricants, Part I. An overview
Authors: Pal Mahendra , Singhal Sudhir 
Published: July 2006

AbstractThe requirement for environmentally adapted lubricants has begun to play an increasingly important role in many industrial applications, particularly in the last two decades. The present‐day requirements for biodegradable and eco‐friendly lubricants imply that lubricants have properties that can minimise, if not eliminate, negative environmental impact, such as contamination of soil and water, caused by lost lubrication, leakage and accidents. The dominant factors that have a direct impact on the environment and which characterise the lubricant and its chemical composition, are toxicity, bio‐accumulation and biodegradability. Biodegradability is perhaps the most important factor which determines the fate of lubricant in the environment.Various commercial, governmental, and regulatory initiatives exist that protect the interests of the consumer. Life cycle analysis can help in assessing the total environmental impact of lubricants. This paper reviews the essential requirements of environmentally adapted lubricants, i.e., chemical composition, eco‐toxicity, biodegradability, bio‐accumulation, and eco‐labelling schemes, and life cycle analysis.
Application of the CONCAWE biodegradability test for oil products
Authors: Battersby N. S. 
Published: July 2006

AbstractInformation on the biodegradability of an oil product (or its components) is needed for classification and labelling purposes. The extent to which a product can be broken down by microbial attack is usually determined using a ‘ready biodegradability’ test (e.g., OECD 301 Test Guidelines). However, these methods are stringent screening tests and can often underestimate the extent to which a product can be removed from the natural environment by biodegradation. CONCAWE (the European oil companies’ organisation for environment, health and safety) has recently developed a test for determining the potential (or ‘inherent') biodegradability of oil products. This is often more useful for assessing the likely impact of an oil product in the event of its release into the environment. This paper gives examples of CONCAWE test results for a number of base fluids and formulated products, and compares these results with those obtained in a ‘ready biodegradability’ test. Guidance is given on the applicability of data that has been obtained using the CONCAWE method.
Delivering synthetic performance with VHVI speciality base fluids
Authors: Henderson H. Ernest , Swinney Brian , Steckle William M. 
Published: July 2006

AbstractHistorically, the best lubrication performance has been achieved by the use of synthetic fluids, such as polyalphaolefins or esters. Advanced commercial processing techniques for producing base oils through significant molecular change are now available. In many applications, automotive and industrial products formulated with these high‐quality API Group III speciality base fluids can achieve the same good performance as that from traditional synthetic fluids.This paper represents continued work to understand and demonstrate features of very high viscosity index (VHVI) speciality base fluids. Ultimately, the performance of a finished fluid is the key market requirement. Actual field performance can vary dramatically, even among polyalphaolefin‐based formulations. Several examples are given to show that equivalent high‐level synthetic performance can be delivered through a synergistic balance of VHVI speciality base fluids and additive chemistry.
Traditional and new approaches to the development of wear‐resistant polymer composites
Authors: Friedrich Klaus 
Published: July 2006

AbstractThis overview describes the development of polymeric composites for operation with low friction and wear against steel counterparts, with special emphasis on injection‐mouldable short‐fibre‐reinforced thermoplastics. This work has aimed to optimise their friction and wear properties and to carry out systematic parameter studies using artificial neural networks; information is presented on the systematic development of continuous‐fibre polymer‐based composites with high wear resistance and on the prediction of their load‐bearing capacity using a finite‐element approach. Finally, some new steps towards the development of functionally graded tribo‐materials are described.
Effectiveness of the ion exchange/vacuum dehydration treatment of phosphate ester fluids
Authors: Collins Kellyanne G. , Duchowski John K. 
Published: July 2006

AbstractPhosphate ester fluids are used in the electrohydraulic control systems of steam turbines. Conditioning agents are often added to the fluids to help prevent their performance being degraded by factors such as hydrolytic breakdown. However, some conditioning agents contain extractable metals that can react to form phosphate soaps or salts, which are also detrimental to the fluids' performance. This paper reports on the nature, origin, and mechanism of formation of these contaminants, with particular regard to those found on ‚last chance’︁ and high‐pressure system filters and in the phosphate ester fluids used by utility companies. Ion exchange/vacuum dehydration (IX/VD) treatment has been found to be effective in removing water, particulates, acid, and phosphate soaps from phosphate ester fluids. Three case studies are outlined wherein the IX/VD treatment of phosphate ester fluids was used to restore the fluids to their original specification. IX/VD treatment is shown to be a cost‐effective means of phosphate ester conditioning.
Behaviour of several lubricants for space applications under transient speed conditions
Authors: Glovnea R. P. , Spikes H. A. , Jones W. R. 
Published: July 2006

AbstractTheoretical work has underlined the importance of squeeze effects in non‐steady‐state elastohydrodynamic (EHD) lubrication when parameters such as load, speed, or geometry vary cyclically. The present paper reports on the results of an experimental investigation into EHD film thickness under start‐stop, ball‐on‐flat contact conditions for four liquid lubricants used in space applications. The conditions studied are representative of those occurring in stepper motor bearing contacts. The lubricants investigated included a multiply alkylated cyclopentane (Pennzane™ SHF 2000), a branched perfluoropolyether (Krytox™ 143 AC), a polyalphaolefin (Nye™ 182), and a linear perfluoropolyether (Braycote™ BXL 413). Measurements were made at two frequencies (2 and 50 Hz) and two temperatures (25 and 80°C). At 50 Hz, corresponding to stop‐start time intervals of 10 ms, there was insufficient time during the stationary periods between motion for any significant collapse of the central film thickness to occur. However, partial collapse did take place at the contact peripheries. Since this collapse occurred in the inlet, it often produced a pronounced reduction in central film thickness during start‐up. It was also found that, during start‐up, a series of film thickness oscillations occurred, resulting in the film thickness becoming successively greater and less than the steady‐state value. This may have a significant effect on the pressure experienced by the contact. Although the four lubricants exhibited similar overall patterns of behaviour, there were considerable differences in the rate of film collapse and in the details of the film thickness reduction and oscillation.
Synthesis and biodegradability of some adipic and sebacic esters
Authors: Kolwzan B. , Gryglewicz S. 
Published: July 2006

AbstractUsing dimethyl adipate, dimethyl sebacate, and neopentyl glycol as starting materials, oligomeric esters with different ranges of molecular mass were synthesised. The transesterification reactions were catalysed with calcium methoxide. The esters have the physicochemical properties appropriate for use as synthetic lubricants. Both the adipic acid esters and sebacic acid esters are characterised by high biodegradability. The esters studied are considered to be environmentally friendly high‐performance functional fluids.
Synthesis and biodegradation of synthetic oils based on adipic and sebacic esters
Authors: Gryglewicz S. , Kolwzan B. 
Published: July 2006

AbstractUsed oils constitute a potential health hazard. Every year several million tons of used oils are released into the environment. At present, environmentally friendly synthetic oils, e.g., esters, are used as alternatives to conventional oils produced from petroleum. The aim of the present work has been to synthesise ester oils and determine their properties, particularly in terms of their biodegradability. Using dimethyl adipate, dimethyl sebacate, and neopentyl glycol as starting materials, oligomer esters with different ranges of molecular mass were synthesised. The syntheses were based on transesterification reactions catalysed by calcium methoxide. The degree of oligomerisation was closely correlated with the molar ratio of the esterification substrates. The esters showed physicochemical properties appropriate for use as synthetic lubricants. Both adipic acid esters and sebacic acid esters are characterised by high biodegradability. The biodegradability depends only slightly on the degree of oligomerisation of the ester molecules. The esters studied were considered as environmentally friendly high‐performance functional fluids.
Effect of temperature on the ageing behaviour of unsaturated ester‐based lubricants
Authors: Zhang X. , Murrenhoff H. , Weckes P. , Hölderich W. 
Published: July 2006

AbstractThe ageing behaviour of trimethylolpropane trioleate was investigated at different temperatures in a modified rotary bomb test apparatus. Some physicochemical properties of ageing oil samples, such as acid value, kinematic viscosity, and iodine value, were measured. The oil samples were analysed using gas chromatography, gas chromatography‐mass spectrometry, and gel permeation chromatography to assess the influence of temperature on the ageing behaviour of ester‐based oils. The results revealed that an increase in temperature could greatly speed up the ageing reaction and increase the formation of decomposition products. However, the degree of oil ageing remained similar when the same quantity of oxygen was consumed.
Phosphate esters with a complex alkyl‐aryl structure considered as tribological fluids
Authors: Mirci Liviu E. , Herdan Jean M. , Boran Sorina 
Published: July 2006

AbstractThis paper presents results of reserch carried out to produce synthetic ester oils with adequate tribological properties, which could also act as antiwear additives. By varying the molar relationship between aliphatic alcohols of variable chain length and a special alcohol with complex alkyl‐aryl structure, namely 2‐[(o‐sec‐butyl)phenoxy]ethanol, two series of new phosphate esters have been synthesised. The influence of the aryl content and the effect of the length of the aliphatic chain on the characteristics of these esters as base oils, and on their qualities as antiwear additives, have been investigated.
Effect of additive molecular structure on friction
Authors: Beltzer M. , Jahanmir S. 
Published: July 2006

AbstractWork is reviewed on the adsorption properties of typical friction reducing additives, at monolayer coverage, operating in the boundary lubrication regime. It looks at adhesive interactions, lateral interactions between adsorbate molecules, and transition temperatures. The adsorption properties of typical friction reducing additives can be accounted for by hydrogen bonding to surfaces and the lateral interactions between adsorbate molecules.
Pour point depressants in lubricating oils
Authors: Denis J. 
Published: July 2006

AbstractThis article begins by describing the main chemical families of pour‐point depressant additives. The normal paraffins remaining in the oil after dewaxing crystallize at low temperature in the form of very thin platelets made up of several layers of associated molecules that are superposed in spirals. These platelets become entangled and prevent the flow of oil. Additives work either by adsorption or by cocrystallization, enhancing the growth of lamella thickness, thus making them less prone to entanglement.
Literature review of OCP viscosity modifiers
Authors: Marsden K. 
Published: July 2006

AbstractOlefin copolymers and terpolymers (OCPs) are used as viscosity modifiers in a large proportion of the European and world multigrade oil market. The polymer properties of the basic ethylene propylene polymers are critical to the physical characteristics of the final lubricant and its engine performance. The important parameters are discussed. Ethylene propylene polymers intended for use in other industrial applications should be checked thoroughly to avoid potential field problems. Modifications of these speciality OCPs to dispersant polymers enhance diesel and dispersant lubricant properties, enabling the most severe lubricant performance requirements to be met. The paper also reviews developments reported in the literature on the production and handling of the products together with their application, particularly with reference to their effect on low temperature properties, engine cleanliness, wear and fuel economy of the lubricant.