bluuebunny/crossref_metadata_2025_split huggingface dataset:
Manufacture of a transformer oil from egyptian paraffinic base stocks via a hydrogenation process
Authors: Abou H. H. , Naga El , El Ashry E. S. H. , Khattab M. A. , Salem A. E. , Boghdady Y. M. 
Published: July 2006

AbstractThis paper describes work aimed at producing a high‐quality transformer oil from local Egyptian paraffinic base stock by hydrogenation, or hydrogenation plus sulphonation.Analysis showed that the neutral base oil 70N was suitable for producing transformer oil. This neutral base oil was chemically treated by hydrogenation under various conditions of temperature, pressure, and time, using two different catalysts, and by hydrogenation followed by sulphonation using optimum conditions. Optimum hydrogenation conditions were achieved by using a Ni/Mo (10 wt. %) catalyst, at 275°C and 100 psi pressure for 60 min, while optimum sulphonation conditions were achieved in previous work by using oleum or SO3 gas at a concentration of 6 wt. % at 35°C for 60 min.Laboratory results and field trials indicated that the neutral paraffinic base oil when so treated meets the IEC 296 international specification for transformer oil, with the exception of the pour point (−18°C). However, this pour point is not relevant in certain hot climatic conditions. Evaluation of the treated oil with commercial transformer oil has shown its potential for use.
Technical note: Extreme‐pressure activity assessment of certain nitrogen and sulphur compounds in lithium‐based grease
Authors: Singh T. , Bhan A. K. 
Published: July 2006

AbstractIn this paper we report on the preparation and extreme‐pressure (EP) activity assessment of certain substituted 1‐amino‐3‐aryl‐2,3‐dihydro‐2‐thioxo‐4,6‐(1H,5H)‐pyrimidinediones as additives in a lithium‐based grease. These additives significantly decreased the wear and friction and possessed the ability to increase load‐carrying capacities and weld loads. Two greases were prepared with the above additives, and both greases exhibited lower values of wear‐scar diameter at higher loads and higher values of weld load in the four‐ball test than the lithium‐based grease alone. The prepared greases also passed rust and corrosion, and oxidation tests.
Boundary lubrication of low‐sulphur diesel fuel in the presence of fatty acids
Authors: Kajdas C. , Majzner M. 
Published: July 2006

AbstractThis paper presents an overview of the effect of aliphatic acids on the tribological properties of selected hydrocarbons and petroleum fractions. The major experimental part of the work focuses on improvements to the lubricity of low‐sulphur diesel fuel. Experiments were carried out using a pin‐on‐disc friction machine and HFRR test rig. The wear results obtained clearly show a specific effect of the test acids dissolved in hydrocarbons in the concentration range 0.005–0.1% (50–1000 ppm). Although the overall picture presented by these results is very complex, it can be concluded that a very small amount of the selected acids dramatically improves low‐sulphur diesel fuel lubricity.
Recovery of residual emulsifiable oil from waste water by flotation
Authors: Omar A. M. A. , Mohamed Mamdouh S. , Ibrahim Hoda 
Published: July 2006

AbstractA source of waste‐water pollution in machining is the lubricating/cooling fluid used. This study investigates the application of the flotation technique for the removal of emulsifiable oil. Research has been carried out on a process of selective separation of oil using mixtures of anionic/nonionic surfactants as collectors and a cationic surfactant as a de‐emulsifier (coagulant). The behaviour of the mixtures at the aqueous solution‐air interface has been studied, and the critical micelle concentration, efficiency, effectiveness, minimum surface area, and free energy of micellisation determined. The effect of the optimum mole fraction of the mixtures on oil separation has been discussed from the point of view of physical parameters. The selectivity achieved can be explained in terms of surfactant concentration and the structure of the micelles.
Possibility of slip in hydrodynamic oil films under sliding contact conditions
Authors: Ono B. , Yamamoto Y. 
Published: July 2006

AbstractIn hydrodynamic lubrication theory, the oil film thickness build‐up increases with increasing sliding speed or oil viscosity, and the viscous resistance or shear stress also increases, both without limit. The entraining force forming the oil film is given by the moving surfaces, or by the adhesive force of the oil molecules on the rubbing surfaces and the interaction force between them. Therefore, the maximum friction force and maximum oil film thickness will be limited by the operating conditions, such as oil properties, rubbing materials, sliding speed, and load. In this study, friction tests were conducted using a plate‐on‐cylinder sliding contact apparatus. It was found that a critical shear stress existed, above which the friction force and oil thickness decreased from theoretical values. Slip in an oil film seems to occur when the theoretical shear stress exceeds the critical value of the oil, according to test conditions. The occurrence of slip in an oil film is responsible for the reduction in the oil film and friction force from theoretical values, leading to the lower‐viscosity components of the oil selectively passing through the conjunction zone.
Frictional behaviour of Pb‐Sn thin‐film lubrication
Authors: Uemura Masao 
Published: July 2006

AbstractThe frictional properties of lead‐tin thin films (thickness of 0.05–0.19 μm) with two types of copper interlayer were investigated. The thin film and the interlayer were formed on a silicon wafer surface by vacuum deposition. Friction tests were carried out using a ball‐on‐disc apparatus in a vacuum chamber. The thin copper interlayer reduced the friction coefficient and prolonged the film life. The effect of load on the friction coefficient is explained by an equation derived using the Hertzian contact area between a sphere and a plate. The thicker copper interlayer did not reduce the friction coefficient but markedly extended the life of the film. In this case, the dependence of the friction coefficient on the load is explained by an equation derived using the Hertzian contact area between a sphere with surface roughness of second order and a plate.
Engine oil ageing under laboratory conditions
Authors: Vipper A. B. , Zadko I. I. , Ermolaev M. V. , Oleinik J. Y. 
Published: July 2006

AbstractIn recent years the role of laboratory methods in investigating the effectiveness of engine oil additives has dramatically increased, especially in predicting the performance of engine oils under field conditions. Some results of research under laboratory conditions on the ageing of engine oils with different performance levels are presented in this paper. The role of the action of antioxidant additives in engine oils for gasoline and diesel engines is described. The paper includes the results of experiments over time in laboratory testing of doped motor oils, use of IR spectroscopy, and reference oils. Single‐ and multi‐cylinder engine test results are also discussed. New, effective additive packages for different engine oils are considered.
Lubrication of a narrow porous journal bearing with a couple stress fluid
Authors: Naduvinamani N. B. , Hiremath P. S. , Fathima Syeda Tasneem 
Published: July 2006

AbstractThis paper describes a theoretical investigation of the rheological effects of couple stress fluids on the performance of narrow porous journal bearings. A most general modified Reynolds equation is derived for narrow porous journal bearings using the Stokes constitutive equations for couple stress fluids. The fluid in the film region and in the porous region has been modelled as a couple stress fluid. The analysis takes into account velocity slip at the porous interface using the Beavers‐Joseph criterion. A closed‐form expression for field pressure is obtained for narrow journal bearings. Eigen‐type expressions for field variations are obtained. The dimensionless load‐carrying capacity, attitude angle, and coefficient of friction are presented for different operating parameters. It is observed that narrow porous journal bearings with couple stress fluids as lubricant show a significant increase in load‐carrying capacity with reduced coefficient of friction as compared to the Newtonian case. The present study predicts the effects of the percolation of polar additives (microstructures) into the porous matrix on the bearing performance.
Designing automotive gear oils for the new millennium
Authors: Hong Hyun‐Soo 
Published: July 2006

AbstractNew engine design changes and ever‐increasing engine requirements make the design of gear oils challenging. A proper understanding of fundamental lubrication theory and formulation knowledge is necessary to develop new gear oils. This paper provides an overview of the fundamentals of lubrication theory and the functions of each additive. Key technical issues facing gear oils are also discussed.
Electrical resistivity and conductivity of greases: An initial study
Authors: Eriksson Erland , Nygård Sven , Lundberg Jan 
Published: July 2006

AbstractInvestigations of railway wagons fitted with rolling‐element bearings have shown damage to the bearings from the passage of electric current. This also occurs in railway wagons without an electric energy consumption of their own, because of residual currents from electric locomotives. This phenomenon gives rise to technical, financial, and even safety problems. This paper reviews research in the field of rolling‐element bearings exposed to electric currents. The paper also reports on an ongoing study undertaken to understand the mechanism of current flow and the role of lubricants in the associated damage, and to identify the possibilities of minimising bearing damage. The obvious solution to this problem is to use optimised greases, i.e., with high electrical conductivity and good lubricating ability.In the preliminary work reported here a number of greases for railway use were tested to determine their electrical conductivity in static and dynamic situations. These tests were performed using specially designed apparatus, and significant initial information about the electrical properties of greases has been obtained in this research, for example, that there is a correlation between the electrical conductance under static and dynamic conditions. All the greases tested showed comparatively high resistivity values, which could be one explanation for the bearing damage observed.
Applications of the concept of tribopolymerisation in fuels, lubricants, metalworking, and ‘minimalist’ lubrication
Authors: Furey M. J. , Kajdas C. , Kempinski R. 
Published: July 2006

AbstractTribopolymerisation, a novel concept of molecular design developed by Furey and Kajdas, involves the continuous formation of thin polymeric films on rubbing surfaces; the protective films formed are self‐replenishing. The antiwear compounds developed are effective with metals and ceramics and in the liquid and vapour phases. Furthermore, they are ashless and contain no harmful phosphorus or sulphur, and many are biodegradable. The potential applications are diverse and have cost, performance, energy, and environmental advantages.The present paper describes some applications of the concept of tribopolymerisation as a mechanism of boundary lubrication, including recent laboratory research and in‐plant industrial demonstrations. Applications include: (a) ashless antiwear or ‘lubricity’ additives for fuels; (b) ashless lubricants for automotive engines to reduce exhaust catalyst poisoning and environmental emissions; (c) lubrication of ceramic engines or ceramic components; (d) machining and cutting using thin films to reduce friction and ceramic tool wear; (e) vapour‐phase applications in high‐temperature gaseous systems or to counter fuel injector wear problems in natural gas engines; (f) special ‘minimalist’ pre‐treatment compositions for engine assembly and running‐in; and (g) enabling technology in the development of new engines and propulsion systems.
Temperature characteristics of the boundary lubricating film of an organocopper compound
Authors: Jianhua Zhang , Changqin Feng , Yuan Zhao 
Published: July 2006

AbstractThe relationship between the temperature and the lubricating properties of an organocopper compound used as a lubricant additive has been studied on steel‐steel rubbing pairs. The results showed that the organocopper compound significantly reduced both the wear and the friction of steel balls for different test temperatures, but that there is a distinction between the friction critical temperature and the wear critical temperature. Results showed that the organocopper additive could improve both the friction critical and the wear critical temperature of a mineral oil. For example, the friction critical temperature increased from 50 to 220°C and the wear critical temperature from 110 to 290°C. Micrographs of the wear scars at different temperatures were used to investigate the lubricating film's temperature characteristics.
Soot characterisation and diesel engine wear
Authors: Jao T.‐C. , Li S. , Yatsunami Kenji , Chen Shiahn J. , Csontos Aladar A. , Howe James M. 
Published: July 2006

AbstractThe hardness of various types of soot produced by heavy‐ and light‐duty diesel engines of European, Japanese, and North American designs was measured by low‐loss electron energy‐loss spectroscopy (EELS). No clear general trend can be established that shows heavy‐duty diesel engine soot is necessarily harder than light‐duty diesel engine soot. The variation in hardness among individual soot particles produced by the same diesel engine can be as large as differences between the hardest soot particles produced by heavy‐duty diesel engines and the softest soot particles produced by light‐duty diesel engines. There are heavy‐duty diesel engines that can produce soot that is softer than that produced by some light‐duty diesel engines and vice versa. Nevertheless, the hardness of all types of soot studied is close to the range of hardness of metal engine parts. Thus, the results indicate that soot is hard enough to abrade some metal engine parts.
MoS2‐based alloys and nanocomposites for solid lubrication
Authors: Savan A. , Haefke H. 
Published: July 2006

AbstractThe development of MoS2 coatings has involved the modification of substrate surfaces, the addition of metals or compounds to the MoS2, and variation in the deposition process parameters affecting the properties of deposited films. More recently, multilayer and periodic nanolayer coating structures have also been investigated. At present, work is concentrated on alloys of MoS2, mainly with various metals, and targeted at terrestrial (ambient air) applications.The addition of metals or compounds to physical‐vapour‐deposited MoS2 has led to improvements in coating performance, for example, greater stability of friction coefficient, greater film endurance, and increased temperature/oxidation resistance. The metal or compound can be either in the form of nanoscale multilayers or mixed with the MoS2, sometimes leading to nanoclusters within a MoS2 matrix. Microstructural analysis seems to show that the primary function of these additives is to suppress the formation of low‐density, columnar structures. At certain concentrations an added metal can also enhance the formation of the tribologically favourable (002) orientation of the MoS2 crystallites. Other changes in the properties of MoS2—metal composites may be due to their oxidation resistance, as indicated by the stability of these films against storage in air and their increased endurance when in sliding contacts at elevated temperatures.
Lubricating properties of thixotropic systems based on overbased calcium sulphonate
Authors: Kobylyansky E. V. , Mishchuk O. A. , Ishchuk Yu. L. 
Published: July 2006

AbstractThe lubricating properties of model systems based on overbased calcium sulphonate have been studied by simulating various kinematic, temperature, and load‐speed conditions of friction machines as well as by investigating the physical chemistry of friction surfaces. It is found that overbased sulphonate complex grease shows good antifriction, antiwear, and extreme‐pressure properties. A synergistic action of calcium tetraborate with overbased sulphonate has been shown. It is found that calcium 12‐hydroxystearate, however, has little effect on lubricating properties, but it improves the thixotropic characteristics of a system.
Molecular dynamics studies of a lubricant system by NMR spectroscopic techniques
Authors: Sarpal A. S. , Sastry M. I. S. , Kapur G. S. , Bansal V. , Mehta A. K. , Bhatnagar A. K. 
Published: July 2006

AbstractThe present studies highlight the applications of NMR spectroscopic techniques for unravelling the unique structural features present in base oils responsible for imparting lubricant properties. The viscosity—temperature and viscosity—pressure properties of base oils of API groups I—IV, such as viscosity, viscosity index, pour point, elastohydrodynamic film thickness, and pressure—viscosity coefficient, have been correlated with the detailed hydrocarbon composition of base oils with an emphasis on the various types of methyl branched structures. Molecular dynamics parameters, such as diffusion coefficient and energy of activation, estimated from the NMR spectral studies have provided evidence of the factors responsible for the different viscosity—temperature or viscosity—pressure characteristics of base oils.
Lubricant oils additivated with polymers in EHD contacts: Part 2. Tests using a four‐ball machine
Authors: Paleu V. , Bercea I. , Cretu S. , Bercea M. 
Published: July 2006

AbstractA mineral oil of low viscosity was additivated with different concentrations of low‐density polyethylene. The wear behaviour of the additivated samples and the base oil was evaluated using a four‐ball wear tester at constant speed and variable load. Steel and ceramic (silicon nitride) were chosen for the balls. The scuffing resistance of the ceramic balls was higher than that of the steel balls. No scuffing appeared in the case of an upper steel ball in contact with lower ceramic balls. As far as the minimum wear‐scar diameter on the lower balls was concerned, an optimum concentration of polymer added to the base oil was found from the experimental data, for both types of ball. For the systems investigated, the optimum concentration was about 1.0% polyethylene.
Lung contusion from focal low‐moderate chest trauma
Authors: Hafen G.M. , Massie J. 
Published: July 2006

AbstractApparently minor chest trauma may result in localized pulmonary contusion. Complications of the contusion, particularly infection, may be delayed. The association between the infection and initial injury may not be appreciated due to the time frame between the injury and clinical presentation. We report two cases of low‐moderate impact pulmonary trauma resulting in focal pulmonary contusion, complicated by infection. Pediatr Pulmonol. 2006, 41:1005–1007. © 2006 Wiley‐Liss, Inc.
Health‐related quality of life of pre‐school children with wheezing illness
Authors: Oostenbrink R. , Jansingh‐Piepers E.M. , Raat H. , Nuijsink M. , Landgraf J.M. , Essink‐Bot M.L. , Moll H.A. 
Published: July 2006

AbstractPre‐school children are frequently affected by wheezing illness, with substantial influences on their health‐related quality of life (HRQL). The Infant/Toddler Quality of Life Questionnaire (ITQOL) is the only generic health status measure for children aged 2 months up to 5 years. In this present study we evaluated the impact of wheezing illness in pre‐school children on the HRQL, using the ITQOL. A questionnaire including the ITQOL and ISAAC questions on frequency and severity of respiratory complaints were sent to parents of patients aged 6 months–5 years visiting the outpatient department with wheezing illness. Scale scores of ITQOL of the included children were compared with general population scores. Using multivariate analysis, the influence of general and clinical characteristics on ITQOL scale scores was evaluated. Results are based on 138 children, 59% male, mean age 34 months. Children with wheezing illness scored differently to the general population sample on 8 of the 11 ITQOL scales. Age, comorbidity and employment of the respondent affected scales on child's physical and emotional functioning and parental functioning. Severity of dyspnoea and wheezing, presence of cough, corticosteroid use, and number of GP visits negatively affected scales on the child's physical and emotional functioning. In conclusion, the HRQL as measured by the ITQOL was lower in a group of Dutch pre‐school children with wheezing illness compared to a general population sample. The scale scores were sensitive to age, co morbidity, socio‐economic situation, and disease severity. Pediatr Pulmonol. 2006, 41:993–1000. © 2006 Wiley‐Liss, Inc.
History of the loss prevention symposia: Forty years, 1967–2006
Authors: Davenport John A. 
Published: July 2006

AbstractIn the early 1960s a number of sizable explosions and fires occurred in the oil and petrochemical industries. A light hydrocarbons plant in Louisiana suffered a vapor cloud explosion. This phenomenon, although it had occurred before, was largely unrecognized in industry. At about the same time, the process industries were moving toward the “jumbo” plants. Formerly, ammonia was produced in multiple plants of 100 to 300 tons/day capacity with multiple parallel lines of reciprocating compressors. However, in the early 1960s ammonia plants having capacities of 750, 1000, and 1500 tons/day with centrifugal machines were rolling off the designers boards. Large, single‐train olefin plants, with capacities of 1.5 billion pounds per year, were also being designed and erected.As a response to these trends, a number of people from industry and insurance put together a symposium to explore ways to improve loss prevention in the process industries. This symposium contained six sessions and was held at the AIChE National meeting in Houston in 1967. Attendance was excellent and a committee was formed to prepare annual symposia on the topic. These symposia are still held at AIChE National meetings with the 40th Loss Prevention Symposium being held this year. This paper will discuss some of the highlights of these symposia and some of the people that have made them so successful over the years. © 2006 American Institute of Chemical Engineers Process Saf Prog, 2006
Thermal conductivity of superfluid B phase 3He in aerogel
Authors: Shahzamanian M. A. , Yavary H. 
Published: July 2006

AbstractWe calculate the thermal conductivity of normal and superfluid 3He impregnated into high‐porosity aerogel by using Kubo formula approach. The thermal conductivity exhibits cross‐over behavior from the high temperature regime, where inelastic quasiparticle‐quasiparticle scattering dominates, to low temperature regim dominated by elastic scattering of quasiparticles off the aerogel. In addition to the relaxation time due to quasiparticl‐quaiparticl interaction (τ int) we include the relaxation time due to collision with aerogel strands (τ imp). By calculating approprate self‐energies these two relaxation times are evaluated. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)