bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of the flaking‐off phenomenon on a jet Engine's shaft bearing using the thin layer activation technique
Authors: Delvigne T. , Chevalier A. , Dubois G. , Escuriol M. , Fehsenfeld P. , Kleinrahm A. , Monnot R. , Pommier S.
Published: July 2006

The Thin Layer Activation technique has been applied in order to study the flake‐off phenomenon on a jet engine's shaft bearing. The external track of the bearing has been activated following the reaction 56Fe(p,n)56Co, over a depth of 80 μm. In spite of a very low activation level, the first signs of flaking‐off were detected 30 min before any significant increase in the vibration level appeared. At that point, the mass of particles leaving the track was measured on line, with a precision of 0.2 mg.
Molecular dynamics simulation of poiseuille flow in ultra thin film
Authors: Hu Y. Z. , Wang H. , Guo Y.
Published: July 2006

The effect of a solid wall on Poiseuille flow of ultra thin film has been simulated by molecular dynamics for a simple Lennard‐Jones fluid. Results showed that the velocity profile and flow are consistent with the prediction of the Stokes equations when the film thickness is considerably greater than the molecular ‘diameter’; that Poiseuille or hydrodynamic flow will be blocked by the solid walls, and the effective viscosity will increase as the film thickness corresponds more closely to only a few molecular diameters; and that when the film thickness is reduced to just the molecular diameter, the fluid molecules between the walls will be solidified or crystallised, and the Poiseuille flow will vanish. This may be one of the mechanisms of transition from hydrodynamic to boundary lubrication.
A single‐pendulum scratch device
Authors: Shu Li , Shizhuo Li , Yanan Liang , Chun Yan , Shenrong Yang
Published: July 2006

A single‐pendulum scratch device together with a relevant methodology has been developed for the tribological investigation of modified surfaces of materials. This device allows determination of energy consumed in a single pass scratch along with normal and tangential forces, as well as wear loss. As a stylus, mounted on a pendulum hammer, touches, penetrates, and grooves, and skims over the surface of the specimen in a short duration, a series of phenomena involving elastic and plastic deformation or fracture occurs. This process is considered to be the best simulation of abrasion and erosion. The newly developed device has proven useful in tribological evaluations of a variety of surface modified materials, such as adhesion of superhard coatings, cohesion of thermal spraying overlays and dynamic hardness of diffusion layers.
A measurement and testing method for lubrication regimes in gear transmissions
Authors: Wang Tie , Li Jinbao
Published: July 2006

This paper describes the measurement and test results on oil film thickness conducted with a self‐contained gear testing machine, with pandimensional power flow, using an improved method of discharge voltage measurement. A series of experiments were conducted in an attempt to measure and analyse the lubrication regimes of involute and double circular arc gear with different lubricants under various working conditions. A formula is provided for calculating oil film discharge voltage following the recorded output of a level recorder.

Experimental results show that such an improved method for discharge voltage is suitable for measurement of film thickness, and that the results are in keeping with the minimum film thickness formula for a double circular arc gear deduced by the authors. The relations between film voltage and the gear parameters of load, rotation speed, lubricant and oil temperature, are also discussed. It is asserted that such a test system has more reliable performance and is more suitable for measuring and analysing the lubrication regimes of gear transmissions than are ordinary experimental systems.
Wear maps for some uncoated cutting tools
Authors: Lim S. C. , Lee S. H. , Liu Y. B. , Seah K. H. W.
Published: July 2006

The method of using maps and diagrams to present wear rates and wear mechanisms, as well as showing the relationships between them, has been applied to cutting tools. In this summary paper, wear maps obtained earlier for uncoated high‐speed steel (HSS) cutting tools are presented together with maps for uncoated carbide cutting tools. Within the two‐dimensional area of a wear map defined by two easily controlled machining parameters, namely feed rate and cutting speed, the rates of tool wear, and the wear mechanisms observed during actual dry turning operations, are displayed. The presence of safety zones and least‐wear regimes in these maps suggests that it may be possible to optimise actual machining operations so that compromises between rates of material removal, for an acceptable level of productivity, and tool costs can be reached. The concept of using machining‐regions maps for practical tool‐wear minimisation during machining is also discussed.
The controlling factor in the formation of transfer films on ceramic surfaces during sliding contact against metals
Authors: Zhou L. , Fang L. , Gao Y. M. , Zhou J. E.
Published: July 2006

A transfer film plays a very important role in the sliding wear process. This paper discusses a factor, ‚adhesive energy’︁, which affects the formation of transfer film on the ceramic's surface during sliding friction of ceramics against metals. On the basis of both a theoretical evaluation of adhesive energies, and experimental results, it can be concluded that the adhesive energy between ceramics and metals is the controlling factor in the formation of transfer film on the ceramic surface. A new semi‐quantitative method to determine the relative thickness of transfer film on ceramic surface with EDAX is discussed.
Life tests on elastomeric lip seals for pneumatic cylinders
Authors: Belforte Guido , Raparelli Terenziano , Mazza Luigi
Published: July 2006

A test method and a testing machine for evaluating the wear of lip seals for pneumatic cylinders are presented. The method and the machine have been evaluated with tests on different types of seals for cylinders with a 50 mm bore. Three levels of lubrication condition were examined: dry, with a film of grease, and with an optimum amount of grease. Differences were noted both between these conditions of lubrication, and between types of seal. © Leaf Coppin 1997.
Tribological behaviour of MW PACVD diamond coatings in vibrating contacts
Authors: Skopp A. , Klaffke D. , Buchkremer‐Hermanns H. , Ren H. , Weiß H.
Published: July 2006

Six diamond coatings were produced by microwave plasma‐assisted chemical vapour deposition (MW PACVD) on polished SiC substrates. Process gas pressure and process gas composition were varied systematically, resulting in different coating morphologies, roughnesses and grain sizes.

Friction and wear were investigated for unlubricated vibrating contact conditions in air at room temperature. Tribological tests on diamond coatings were performed in a ball‐on‐disc configuration, with steel balls (100Cr6) and alumina balls acting as counterbodies. For comparison of the tribological performance of the diamond coatings, standard tests were performed with a stroke of 200 μn, a load of 10 N, and a frequency of 20 Hz. The effect of relative humidity (RH) was investigated by testing in dry (3% RH), in normal (50% RH), and in moist air (100% RH), respectively To investigate running‐in effects and wear propagation, the test duration (104, 105, and 1.2·106 sliding cycles) was varied.

For steel/diamond pairings, high wear at the steel ball and high friction were measured, influenced by roughness and grain size of the diamond coating and by relative humidity. For Al2O3 against diamond, a pronounced running‐in of friction and wear was found. High friction and high wear at the beginning of each test are followed by a stationary phase with extremely low friction coefficients (⩽ 0.05) and with wear rates below the limit of resolution. This running‐in depends on grain size and roughness of the coating, on relative humidity, as well as on the operational parameters. Surface analysis using SEM, EDX, LRS and AFM was conducted, to investigate tribologically induced surface changes.
Diagnosis and condition monitoring of medium‐speed marine diesel engines
Authors: Kouremenos D. A. , Hountalas D. T.
Published: July 2006

Diagnosis of diesel engines is not new and various methods have been proposed in the past for fault diagnosis. The problems relating to marine diesel engines, especially medium‐ and high‐speed engines, are due mainly to their large size, which does not allow the use of trial and error methods, and their high operating speed. The most difficult problem occurs when the engine is not able to produce its maximum power, while there is no obvious fault or error. In the present work a method is described which attempts to offer a solution to such problems. The method is a thermodynamic one based on a simulation model and the processing of measured engine data. Presented is an application of the method to a medium‐speed marine diesel engine, which suffered from low power output accompanied by high exhaust gas temperatures. The results from application of the method show that the problem is not a direct one, but is caused by many factors that result in improper operation. With this method, the current engine condition can be discovered, and suggestions made for proper tuning or repair. After conducting such an analysis, a vessel was able to achieve its maximum cruising speed, showing that the proposed method is a promising one.
Coking and microcoking: Tools for evaluating and developing lubricant additives
Authors: Cazin J. , Abellaneda G. , Brégent R. , Pascal J. C.
Published: July 2006

Two tests for evaluating an engine lubricant's tendency to form deposits at high temperature have been developed by a working group of the GFC,

Groupement Français de Coordination (French Coordination Group).

set up to establish laboratory pre‐selection tests. The first is a new static microcoking test where the oil is deposited on an aluminium alloy plate and submitted to thermal conditions similar to those found in the piston ring zone of an IC engine. The results are analysed to determine the temperature at the oil's thermal stability limit and to evaluate the quantity and nature of the deposits in the form of varnish, according to a grading system based on the CEC M‐02‐A‐78 method of gauging engine cleanliness. The second is an improved panel coking test in which a thin film of oil of a given volume is fed on to a stainless steel panel, at high temperature, and the deposits formed at the end of the test are evaluated, again using the CEC rating method, in terms of quantity and type (carbon or varnish).

In addition, a video system has been designed to grade the micro‐coking panels through colour recognition. This not only allows visual grading to be faithfully reproduced but also eliminates the subjective element of colour grading. The results obtained with the ‘Video‐Rater’ constitute a first step towards computer‐assisted grading of engine parts.
A tribotesting method for evaluating cemented carbide tribo‐performance
Authors: Scieszka S. F. , Filipowicz K.
Published: July 2006

The abrasive wear properties of materials in sliding contact with solid mineral particles during the comminution process have been studied. The equipment used can simulate the tribo‐conditions inside coal pulverisers. Using this experimental apparatus, a number of different cemented tungsten carbides have been tested and classified according to their resistance to abrasive wear in rubbing contact with particulate coal. The paper shows that the wear results can be used to estimate the resistance of a material to brittle fragmentation and chipping of the edges during tribo‐contact with solid particles. An equation is presented which enables calculation of the fracture resistance factor, KWR, based on results from carefully controlled repeated abrasion tests.
MEMs hydrodynamic bearings: Applications to and implications for machine failure prevention
Authors: Wood Kristin L. , Neikirk Dean , Busch‐Vishniac Ilene , Weldon William , Chu Chin‐Seng , Kim Youndmin , Gupta Vikas , Maddox William , Masser David
Published: July 2006

Microdynamic systems have been studied for a number of years. Only limited work, however, has been completed on integrating microdynamic components into systems that satisfy mechanical tasks on macroscopic scales. In this paper, we describe microdynamic components needed to produce a surface which is actively deformable on local scales. In particular, we consider the design and demonstration of smart journal and thrust bearings capable of using embedded sensors and actuators to change dynamically the surface geometry. The ability actively to deform bearing surfaces allows for the design of bearings which are less prone to failure, the design of bearings with greater load‐carrying abilities, and a fundamental study of the effect of surface geometries and fluid conditions on bearing performance, such as start‐up and shut‐down conditions. Some results of our new bearing designs are presented, focusing on numerical bearing models, sensor and actuator design and fabrication, and physical experimentation.
Application of an envelope technique in the detection of ball bearing defects in a laboratory experiment
Authors: Toersen Henk
Published: July 2006

To judge the diagnostic capabilities of an envelope technique, based on enveloping the resonance frequency of a transducer,

Bearcon Signature™, Carl Schenck AG, Germany

artificially damaged ball bearings (SKF 6207) were run under oil lubrication at different radial loads and speeds in a laboratory experiment. Damage to the outer race, inner race and ball of different magnitudes was introduced by spark erosion and the response of the measurement system was analysed. The results showed that vibration spectrum components of outer race defects showed up in the envelope spectra of undamaged bearings, and that the detectability of defects was primarily limited by the speed of the bearing; on occasion the automatic scaling facility of the analyser was a limiting factor. Inner race and ball defects showed the well‐known effects of load modulation in the defect contact zone, which can become dominant in the envelope spectra at high loads and speeds. This phenomenon could be confirmed by computer simulation. The detection of ball damage was hampered by the fact that overrolling of the defect in purely radially loaded bearings takes place incidentally. This drawback could be mitigated by applying a trigger technique to the envelope signal.
Gear crack propagation investigations
Authors: Lewicki David G. , Ballarini Roberto
Published: July 2006

Analytical and experimental studies were performed to investigate the effect of gear rim thickness on crack propagation life. The FRANC (FRacture Analysis Code) computer program was used to simulate crack propagation. The FRANC program used principles of linear elastic fracture mechanics, finite element modelling, and a unique re‐meshing scheme to determine crack tip stress distributions, estimate stress intensity factors, and model crack propagation. Various fatigue crack growth models were used to estimate crack propagation life, based on the calculated stress intensity factors. Experimental tests were performed in a gear fatigue rig to validate predicted crack propagation results. Test gears were installed with special crack propagation gauges in the tooth fillet region to measure bending fatigue crack growth. Good correlation between predicted and measured crack growth was achieved when the fatigue crack closure concept was introduced into the analysis. As the gear rim thickness decreased, the compressive cyclic stress in the gear tooth fillet region increased. This retarded crack growth and increased the number of crack propagation cycles to failure.
A software‐based measurement system for testing and analysis of automotive brake squeal
Authors: Bergman Filip , Eriksson Mikael , Jacobson Staffan
Published: July 2006

A software‐based measurement system using both analogue data acquisition and digital communication via a general‐purpose interface bus (GPIB) board has been developed for analysis and evaluation of disc brake squeal. The system is built around a computer and based on commercial software. Brake pressure and torque, rotational speed, five different temperatures, and sound emission are logged once a second. If the sound is characterised as a squeal it is saved to file together with the other parameters.

The measurement system is very flexible, allowing for different types of instruments and sensors to be used by adapting the software. Furthermore, the same software is used for evaluation of the collected data.

Mechanically, the equipment consists of a complete front wheel suspension where the original brake disc and caliper are mounted in a steel tube chassis. The brake disc is driven by a DC electric motor, while a hydraulic system provides the brake pressure. Brake pressure and rotational speed can be controlled independently.
NMR and DSC studies of base oils
Authors: Adhvaryu A. , Pandey D. C. , Singh I. D.
Published: July 2006

The effect of the composition of a base oil matrix on additive response is an indication of its behaviour in a dynamic system. In this paper, a novel method involving quantitative 1H and 13C NMR to explain the molecular chemistry of base oil is used. Oxidative degradation of base oils (pure as well as additivated) has been studied using DSC. The results are explained in terms of molecular composition of the different base stocks to get a clear understanding of additive response in a matrix of different hydrocarbon oils.
A method of measuring oil consumption by labelling with radioactive bromine
Authors: Zellbeck H. , Bergmann M. , Röthig J. , Seibold J. , Zeuner A.
Published: July 2006

A method of determining the oil consumption rate of combustion engines is presented. It is based on labelling the individual oil fractions of engine oil with radioactive bromine isotope82 Br and on the quantitative absorption of radioactive bromine compounds in the exhaust gas in an aqueous solution of nitric acid and silver nitrate. The advantages of this method are that the oil that is consumed in the exhaust gas can be directly measured, without the fluctuating amounts of oil in the sump influencing the result, and the behaviour of the individual components of the oil in the consumption process can be determined. The test is quick, only twenty minutes being required to detect oil consumption at one operating point; and with a single labelling, the oil consumption at a great number of working engine points can be measured 82 Br has a short half‐life of only 36 h, so that compliance with radiation protection measures is inexpensive and investigations can be carried out using a conventional testing device.

As part of the research project, a study was made of the influence of different base oil types, with and without polymer additives, on consumption. Results showed that Noack evaporation loss correlated with oil consumption only with boiling fractions of exactly the same base oil, and not with different, in particular synthetic, base oils; that polymer additives (VI improvers) significantly reduced the rate of oil consumption; and that the polymer additive and the type of base oil both had more influence on oil consumption than viscosity.
Engine friction lubricant sensitivities: A comparison of modern diesel and gasoline engines
Authors: Taylor R. I.
Published: July 2006

Engine friction models have been developed that take account of the variations in lubricants with temperature, shear rate, and pressure. These models have been used to study the lubricant sensitivities of modern diesel and gasoline engines. Total engine friction losses for a Perkins Phaser four‐cylinder, 4.0 l, turbocharged, inter‐cooled diesel engine, operating at 1300 rpm, with an SAE 15W‐40 lubricant, were estimated at approximately 2 kW, with the piston assembly contributing 46%, the bearings 49%, and the valve train 5%. Total engine friction losses for a Mercedes Benz M111 2.0 l gasoline engine (used in CEC sludge and fuel economy engine tests) operating at 2500 rpm, and medium load, for an SAE 15W‐40 lubricant, were estimated at 1.5 kW, with the piston assembly contributing 42%, the bearings 39%, and the valve train 19%.
Maximising the fuel efficiency of engine oils: The role of tribology
Authors: Korcek Stefan , Jensen Ronald K. , Johnson Milton D. , Sorab Jagadish
Published: July 2006

Improvement of engine fuel efficiency is one of the most important goals of current automotive development. Maximising the contribution of engine oils to fuel efficiency is a very important part of this process. Engine friction modelling, based on fundamental tribological considerations, has shown that further engine friction improvements are possible through engine oil reformulation. This reformulation should minimise friction under hydrodynamic conditions through modification of the rheological properties of oils, and also minimise friction under mixed and boundary lubrication conditions through changes in the chemical composition of the oils. These improvements can be achieved by appropriate selection of a base oil as well as by the use of effective friction‐reducing additive systems. A very important consideration in formulating these highly fuel‐efficient oils is their ability to retain their fuel efficiency during the entire oil service interval. This paper describes the role of tribological research in the development and introduction of advanced fuel‐efficient engine oils.
Surface roughness measurements as a method for tribological characterisation of ball bearings
Authors: Delfosse D. , Thoma K. , Mueller U. , Ampuero J.
Published: July 2006

A 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

A 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

Finite‐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

In 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

One 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

In 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

Optical 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

The 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

This 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

The 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

A 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

The 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

The 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

In 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

Under 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

The 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

Many 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

This 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

In 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.
Copper complexes of (−)‐epicatechin gallate and (−)‐epigallocatechin gallate act as inhibitors of Ribonuclease A
Authors: Ghosh Kalyan Sundar , Maiti Tushar Kanti , Mandal Abhishek , Dasgupta Swagata
Published: July 2006

Green tea polyphenols, which have the ability to inhibit angiogenesis, form complexes with Cu(II), a known potent stimulator of blood vessel proliferation. Copper complexes of (−)‐epicatechin gallate and (−)‐epigallocatechin gallate were found to inhibit the enzymatic activity of Ribonuclease A (RNase A) as revealed by an agarose gel based assay and urea denatured gel electrophoresis. The copper complexes were found to be non‐competitive inhibitors of RNase A with inhibition constants in the micromolar range. Changes in the secondary structure of the protein are found to occur due to the interaction as revealed from Fourier transform infrared and circular dichroism studies.
Accidental Use of the Median Nerve as an Interposition Material in First Carpometacarpal Joint Arthroplasty
Authors: TOROS T. , VATANSEVER A. , ADA S.
Published: July 2006

Harvesting the median nerve accidentally as a tendon graft, is a major complication of upper extremity surgery which is noted only rarely in the literature. This article seems to be the first report of the median nerve being used as an interposition material in first carpometacarpal joint arthroplasty.
A multi‐theoretic perspective on trust and power in strategic supply chains
Authors: Ireland R. Duane , Webb Justin W.
Published: July 2006

Strategic 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

Supply 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.
Familial systemic amyloidosis associated with bilateral sensorineural hearing loss and bilateral facial palsies
Authors: Hornigold R , Patel A V , Ward V M M , O'Connor A F
Published: July 2006

The Finnish type of familial amyloid polyneuropathy due to variant gelsolin is a rare form of familial amyloidosis. The subtype was first described in 1969 and is characterized by progressive cranial neuropathies, corneal lattice dystrophy and distal sensorimotor dysfunction. It is extremely uncommon, with only two families known to be affected in the UK. We discuss the case of a 70-year-old woman who presented with bilateral facial nerve palsies, bilateral sensorineural hearing loss and Finnish type familial hereditary amyloidosis. A literature search of the Medline database (1966–2005) was performed, using the keywords ‘amyloid’, ‘hearing loss’ and ‘facial palsy’; however, this association appears to be a novel finding. We review the current literature and discuss otorhinolaryngological presentations of amyloidosis.