bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface roughness measurements as a method for tribological characterisation of ball bearings
Authors: Delfosse D. , Thoma K. , Mueller U. , Ampuero J. 
Published: July 2006

AbstractA series of experiments using steel or hybrid balls in an SNFA VEX25 type bearing was conducted, at a rotational speed of 50,000 rpm. The race material was 100Cr6 steel, whereas for the balls various steels, coatings, and ceramics were used. The different materials used for the balls as well as the method of lubrication (air/oil or grease) strongly influenced the surface degradation of the ball bearings. Hybrid bearings with ceramic balls showed very little wear of either the balls or the steel races, and so offer potential for high‐speed applications. The degradation of the bearings was examined using scanning electron microscopy, atomic force microscopy, and laser scanning profilometry. The disadvantages and advantages of these methods are given, along with the results of surface roughness measurements.
Fuel economy of multigrade gear lubricants
Authors: Bala V. , Brandt G. , Walters D. K. 
Published: July 2006

AbstractA light‐duty axle efficiency test for evaluating gear lubricants for their fuel economy performance is described. Data collected for an internal reference oil highlight the repeatability of the test with different axles. Comparisons between single‐grade SAE 90 and multigrade gear lubricants were made under a variety of pinion torques and speeds to simulate highway and city driving conditions. Lubricant rheology and its importance in maintaining film strength for adequate bearing and gear lubrication for optimum torque efficiency and axle temperature are discussed.
Finite‐element heat‐transfer analysis of a PEEK‐steel sliding pair in a pin‐on‐disc configuration
Authors: Kónya László , Váradi Károly , Flöck Joachim , Friedrich Klaus 
Published: July 2006

AbstractFinite‐element (FE) thermal models have been developed in order to study the temperature distribution in a sliding pair comprising a poly(ether ether ketone) (PEEK) pin and a steel disc in a pin‐on‐disc configuration. First, a moving heat source model for the disc was created. An alternative distributed heat source model was also produced in order to reduce computing time for the evaluation of the moving heat source model by some orders of magnitude. This latter model gave the same results as the moving heat source model, except for a small region just below the moving heat source. On the basis of the distributed heat source approach, a complete axisymmetric FE model for the disc side (taking the effect of thermal resistance between the assembled components into consideration) and a steady‐state quarter model for the pin were developed. Water cooling and air cooling of the steel shaft were also compared. It was found that air cooling allowed a higher temperature in the contact region of the two sliding partners. The experimental results obtained with thermocouples and a thermal camera showed good agreement with the model predictions.
Friction and wear effects on a micro/nano‐scale
Authors: Santner E. 
Published: July 2006

AbstractIn this paper are described tribological effects which can be found in micro‐tribological systems, and in those macro‐systems which can be analysed by micro‐methods, e.g., by atomic force microscopy (AFM) or related methods. Micro‐tribology systems have friction contacts with loads in the micro/nano‐newton range and/or dimensions in the micro/nanometre range. Experiments on the micro/nano‐scale should be easier to explain by theoretical modelling due to their simpler system structure. An example is discussed of adhesion and friction measurements between AFM tips and clean, flat, solid surfaces in ultra‐high vacuum, which shows some of the special aspects of micro/nano‐tribology. Surprising friction characteristics on surfaces with an artificial micro‐structure can be explained by skilled and careful topographical analysis of the friction path with an AFM. In micro‐sensor contacts, ‘single wear events’ can be detected using AFM analysis of the contact region. For ceramic compounds, different friction levels for the components of the material can be found. The problems, difficulties, and dangers of misinterpretation are also discussed.
Evaluation of metallic elements in oil for an engine fault‐diagnosis system
Authors: Macián V. , Tormos B. , Lerma M. J. 
Published: July 2006

AbstractOne of the main problems in using oil analysis for predictive maintenance is the processing of the results. The oil analysis technique allows one to obtain relevant information about the state of the lubricant, the engine, and other auxiliary elements. However, it is necessary to process this information and to define the references with which the numerical results must be compared. The evaluation of metallic elements, wear particles, or contamination particles is more difficult, because factors such as engine metallurgy, engine use, and age must be considered. Therefore, the effect of various factors on the value measured, such as refills, different periods of sample taking, or types of oils, must be eliminated. A system to evaluate metallic elements in oil for an engine fault‐diagnosis system is presented in this paper.
Development of an improved method for investigating the frictional properties of lubricants under transient EHD conditions
Authors: Åhrström B.‐O. 
Published: July 2006

AbstractIn the design and evaluation of mechanical system performance it is important to know the frictional qualities of the lubricant. Without correct numerical treatment of the lubricant during simulations of large systems, e.g., drive trains in trucks and buses, the results will, to a large extent, be inaccurate. However, obtaining detailed information places demands on the test equipment as the events are both transient and highly loaded. Under quasi‐static conditions, forces are measured with force transducers, but in elasto‐hydrodynamically lubricated conjunctions, where pressures are so high that the surrounding surfaces deform elastically, this cannot be done without permanently damaging the equipment. The conceptual design of the test equipment must therefore incorporate the measuring process in transient conditions (loading‐unloading times of 200–500 μs) being performed in real time, and allow extreme pressures of up to 3 GPa without component destruction.One way to obtain accurate friction data successfully is to apply a concentrated force pulse to a non‐instrumented surface and to measure the response from that pulse elsewhere. The development of a measurement technique, the Lulea ball and bar apparatus, which utilises wave propagation theory, is presented in this paper. An oblique impact on a robust end plate on a rod was used to generate both non‐dispersive compression waves and dispersive flexural waves. The normal force created by the axial wave was measured using strain gauges, while the transverse force was derived from the fast Fourier transforms of two lateral acceleration histories, using dynamic beam theory. The relation between the normal and tangential force histories showed the frictional properties at the impact as a function of time. A variety of lubricants was also studied at Hertzian pressures of up to 2.5 GPa, and the development of the method and results are presented. Experiments indicate that different lubricants exhibit different frictional properties and that the resolution in the test equipment is sufficient to indicate this.
Optical analysis of surfaces by second‐harmonic generation: Possible applications to tribology
Authors: Marrucci L. , Paparo D. , Cerrone G. , Solimeno S. , Russo R. , Lenza T. L. , Siano P. 
Published: July 2006

AbstractOptical second‐harmonic generation is a recently developed technique in surface science, the range of applications of which has been steadily broadening. It allows, among other things, the direct probing of molecular adsorption on to a solid substrate from a liquid or gaseous environment. This paper reports on the possibility of applying it to tribological studies. A set of possible experiments that could offer information, in particular, on the working principle of those oil additives, commonly used in the lubricant industry, whose effect derives from surface adsorption, are discussed briefly. In addition, the preliminary results of a first experiment are described.
Effect of the dynamic response of fretting devices on test results
Authors: Ramalho A. 
Published: July 2006

AbstractThe dynamic response of equipment and measurement systems can have a significant influence on results. These effects have a particular importance in experimental fretting studies owing to the frequency levels usual for these kinds of test. In the present work the measuring systems used in fretting rigs to measure friction force are modelled using a lumped mass system with a single degree of freedom. Correction factors are calculated for application to the amplitude and the phase of the measured friction force. The application of these factors to a case study is demonstrated. The distortion of the phase introduced by some filtration techniques is also discussed.
A method for testing lubricants under conditions of scuffing. Part II. The anti‐seizure action of lubricating oils
Authors: Piekoszewski W. , Szczerek M. , Tuszynski W. 
Published: July 2006

AbstractThis paper describes an investigation of lubricating oils under extreme‐pressure (EP) conditions in a specially modified four‐ball tester. A new test method developed at the Tribology Department of ITeE described in Part I of this paper was used. In this, during a test run, the applied load is increased continuously and the friction torque is measured. A sudden increase in the friction torque indicates the collapse of the lubricating film — where scuffing is initiated. The load at this moment is called the scuffing load. If the load is increased further, it is possible to observe scuffing propagation until seizure occurs, i.e., a defined, maximum friction torque is reached. Thus, scuffing is considered as a process leading to seizure.Using the method, tribological experiments were performed employing various lubricating oils consisting of viscosity‐index improvers and antiwear (AW) and extreme‐pressure (EP) additives added to a base oil. Mineral and synthetic base oils of different kinematic viscosities were used. The aim was to investigate the influence of such lubricants on scuffing initiation and propagation with the present methodology.In Part I it was shown that scuffing initiation depends strongly on the kinematic viscosity of the lubricant; the higher the viscosity, the greater the scuffing load. The presence of AW and EP additives in the lubricant increases the scuffing load significantly. It was also shown that the kinematic viscosity of the lubricant oils has no effect on scuffing propagation. However, scuffing propagation is significantly mitigated by AW and, to a greater extent, by EP additives. The results of surface analyses show the decisive nature of the chemical reactions of AW and EP additives with the steel ball surface under scuffing conditions, as well as the possible diffusion of sulphur and phosphorus. Chemical reactions and diffusion lead to the creation of an inorganic surface layer (probably iron sulphide), the good anti‐seizure properties of which limit scuffing propagation.
Determination of molecular weight distribution parameters of polymers and additives by field desorption mass spectrometry
Authors: Vivekanandan K. , Vatsala S. , Chopra A. , Basu B. , Jain M. C. , Bhatnagar A. K. 
Published: July 2006

AbstractThe applicability of the field desorption mass spectrometry (FD‐MS) technique to the determination of the molecular weight distribution parameters of various commercially available petroleum sulphonates is demonstrated. The technique has been substantiated using standards such as polyethylene glycols, polystyrenes, and sodium petroleum sulphonates. This study of molecular weight averages compares the results from gel permeation chromatography and FD‐MS.
A method for the tribological testing of thin, hard coatings
Authors: Michalczewski R. , Piekoszewski W. , Szczerek M. , Tuszynski W. 
Published: July 2006

AbstractA new method has been developed for tribological testing of thin, hard antiwear coatings, using a ball‐on‐disc tribosystem, under conditions of dry sliding. In this, an Al2O3 ball is pressed against a coated steel disc. Wear debris is removed from the contact zone by a stream of dry argon in this novel method. This improves the stability of the tribological properties and the repeatability of the test results. All test conditions are precisely defined, in particular: the type of motion, air relative humidity, ambient temperature, sliding speed, load, tribosystem spatial configuration, substrate material, substrate hardness and roughness, and coating thickness. The method developed has been used to test various physical vapour deposition coatings (deposited by the vacuum arc method), i. e., single‐layer TiN, Ti(C,N), CrN, and Cr(C,N), and multilayer Cr(C,N)/CrN/Cr and Cr(C,N)/(CrN+Cr2N)/CrN/Cr. It is shown that CrN coatings exhibit the best antiwear properties, and Ti(C,N) the worst. Friction coefficients for CrN and Cr(C,N) coatings are much lower than for the more commonly used TiN. Multilayer coatings have better antiwear properties than single‐layer ones.
Tribological behaviour of SiCTiCTiB2 composites under unlubricated sliding conditions
Authors: Klaffke Dieter , Wüsche Rolf , Rasim Yarim 
Published: July 2006

AbstractThe friction and wear behaviour of eight different SiCTiCTiB2 composite materials, with a practically constant SiC:TiC ratio of 1 and an increasing amount of TiB2, was determined comparatively in oscillating sliding tests at room temperature under unlubricated conditions. The influence of the relative humidity (RH) of the surrounding air was investigated in tests in dry, normal, and moist air. All tests were performed against SiC balls and Al2O3 balls as counterbodies. The friction was affected by RH but barely at all by the composition of the composites. The wear resistance of the composites was found to be improved considerably by addition of TiB2 in the range 20–60%. The highest wear resistance of the system was found when Al2O3 was used as the counterbody material.
Tribological behaviour of steel‐alumina sliding pairs under boundary lubrication conditions
Authors: Hwang D.‐H. , Ghar K.‐H. Zum 
Published: July 2006

AbstractThe tribological behaviour of oil‐lubricated steel‐alumina sliding pairs was investigated using a ball‐on‐disc tribometer at room temperature. Commercial bearing balls of 10 mm diameter were mated to 99.7% Al2O3 discs, and additive‐free mineral oil was fed into the contact area. The sliding speed and the applied normal load were varied, and the initial surface roughness of the Al2O3 disc was altered using different polishing and grinding procedures. The results showed that the surface roughness of the ceramic discs dominated the tribological behaviour under the given experimental conditions. The sliding speed as well as the normal load showed less effect on the friction behaviour, but the amount of wear depended strongly on the normal load. From the results it was concluded that improvement of the surface roughness and optimised surface machining of the ceramic material can be essential for improving the tribological performance for boundary‐lubricated steel‐ceramic sliding pairs.
The dynamic measurement of surface topography using a light‐section technique
Authors: Wang W. , Wong P. L. 
Published: July 2006

AbstractIn this paper, a recently developed light‐section technique is demonstrated as a viable technique for the measurement of the topography of moving surfaces. The sensitivity and precision of this technique are statically and dynamically evaluated for samples of different roughness. It is shown that an optical system using the light‐section method is not only precise but also immune to the effects of perpendicular and lateral motion of the surface. It is therefore well suited to on‐line monitoring of the change of profile of moving surfaces. The technique, with its ability to measure the topography of moving surfaces without contact, provides a most effective tool for the study of wear and lubrication mechanisms under partial elastohydrodynamic lubrication.
Effect of Nickel on the Wear Rate of Fe‐Cr‐C‐Ni Steel Under Sliding Friction
Authors: Novytskyy V. G. 
Published: July 2006

AbstractUnder sliding friction, nickel (0.3–4.2 wt.%) alloyed with chromium steel (1.2 wt.% carbon; 15 wt.% chromium) exerts a fundamental influence upon the initial structure of the steel and the phase composition and structure of the near‐surface friction layers. The minimum wear of the steel occurs when there is a dynamic equilibrium between the dislocation densities in the α‐ and γ‐phases and a ratio between the γ‐ and α‐phases of 50:50 for steels after quenching and 25:75 for steels after tempering in the near‐surface friction layers.
Influence of Normal Force and Humidity on the Friction and Wear of Unlubricated Reciprocating Sliding Steel/Steel Couples
Authors: Klaffke D. 
Published: July 2006

AbstractThe friction and wear behaviour of different steel/steel couples was investigated in laboratory tests with unlubricated reciprocating sliding motion. Two different steel balls were tested against two different steel discs in dry, normal, and moist air at room tem‐perature. The influence of normal force on friction and wear was studied in the range from 1 to 10 N for all three levels of relative humidity (RH). RH strongly influenced wear behaviour for all four couples, while the friction behaviour was less affected by RH. For all the couples, normal force was found to influence wear rate with a tendency for the wear rate to increase with decreasing normal force. The coefficient of friction also increased with decreasing normal force, but to a much lesser extent than that evaluated for the wear rate.
Influence of Temperature and Relative Humidity on the Friction and Wear of Unlubricated Reciprocating Sliding Steel/ Steel Couples
Authors: Klaffke D. , Sander H. , Hartelt M. 
Published: July 2006

AbstractMany tribosystems are subjected to different conditions with respect to temperature and humidity. Reciprocating sliding tests with steel/steel couples were performed using a laboratory test rig in air with varying relative humidity and temperature. During each test the friction force, the total linear wear, the electrical contact resistance, and the acoustic emission were recorded. Tests with self‐mated couples of bearing steel (100r6) and of stainless steel (X10CrNiMoNb18‐10/X5CrNi18‐9) in a ball‐on‐disc arrangement revealed small effects of temperature and humidity on friction, but a strong effect of the water vapour content on the wear rate of the system. Attempts were made to correlate changes of wear behaviour with different wear mechanisms.
Development and Significance of the Phosphorus Emission Index of Engine Oils
Authors: Selby T. W. 
Published: July 2006

AbstractThis paper reports the author's effort to verify some of the present assumptions regarding causes and relationships in the volatility of engine oil phosphorus. Using Selby‐Noack volatility data from 1300 engine oils collected by the Institute of Materials in three areas of the world, volatilised phosphorus showed very low statistical dependence on either oil volatility or phosphorus concentration in the fresh oil. Rather, the data seemed to indicate that the chemistries of the phosphorus‐containing additives and their formulation with other additives were the controlling cause of phosphorus volatility and, by extension, emission level.The study permitted the development of a phosphorus emission index that predicts the emission potential of a formulated oil based on the amount of phosphorus found in the volatilised oil collected in the Selby‐Noack test.
Peripheral endothelin A receptor antagonism attenuates carcinoma‐induced pain
Authors: Schmidt Brian L. , Pickering Victoria , Liu Stanley , Quang Phuong , Dolan John , Connelly S. Thaddeus , Jordan Richard C.K. 
Published: July 2006

AbstractIn this study we investigated the role of endothelin‐1 (ET‐1) and its peripheral receptor (ET‐A) in carcinoma‐induced pain in a mouse cancer pain model. Tumors were induced in the hind paw of female mice by local injection of cells derived from a human oral squamous cell carcinoma (SCC). Significant pain, as indicated by reduction in withdrawal thresholds in response to mechanical stimulation, began at four days after SCC inoculation and lasted to 28 days, the last day of measurement. Intra‐tumor expression of both ET‐1 mRNA and ET‐1 protein were significantly upregulated compared to normal tissue, and local administration of the ET‐A receptor selective antagonist, BQ‐123 (100μM) significantly elevated withdrawal thresholds, indicating the induction of an antinociceptive effect. These findings support the suggestion that ET‐1 and ET‐A receptors contribute to the severity of carcinoma‐induced soft tissue cancer pain.
A multi‐theoretic perspective on trust and power in strategic supply chains
Authors: Ireland R. Duane , Webb Justin W. 
Published: July 2006

AbstractStrategic supply chains serve as a potential source of competitive advantage for firms. The ability of a strategy supply chain to engender cultural competitiveness, or joint entrepreneurship and learning aimed at filling market gaps, is a key path through which a strategic supply chain may become a competitive advantage. A balance of trust and power within the supply chain offsets uncertainty and risks associated with the behaviors underlying cultural competitiveness. Using a multi‐theoretic perspective, we discuss four strategies that firms use to balance a climate of trust and power in a strategic supply chain. Identifying an authority, generating a common supply chain identity, utilizing boundary spanning ties, and providing procedural and interactive justice are the strategies we discuss.
Happy together?
Authors: McCarter Matthew W. , Northcraft Gregory B. 
Published: July 2006

AbstractSupply chains are beginning to displace firms as the competitive entity in the global marketplace. Managed supply chains offer the promise of added value through proactive cooperative efforts among participating firms. However, as a strategic alliance, managed supply chains represent a form of social dilemma: supply chain alliances may fail because participating firms fear opportunistic behavior on the part of other alliance participants, and as a consequence underinvest their information and resources into the alliance. The interdependence structure of the alliance may contribute to this problem. Viewing managed supply chains as a form of social dilemma also identifies solutions that may be implemented unilaterally by individual firms or jointly by the alliance to maintain the “indispensable virtue” of high trust that allows supply chains to effectively create added value.