bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemically Modified Carbon Paste Electrode for Determination of Sulfate Ion by Potentiometric Method
Authors: Soleymanpour Ahmad , Asl Ezzat Hamidi , Nasseri Mohmmad Ali
Published: July 2006

Four Schiff base complexes of different metal ions, M=Cr(III), Mn(III), Fe(III), and Co(III), were studied to characterize their ability as sulfate ion carriers in carbon paste electrode (CPE). The modified CPE electrode with Schiff base complex of Cr(III), N,N′‐ethylenebis(5‐hydroxysalicylideneiminato) chromium(III) Chloride, showed good response characteristics to SO42− ion. The proposed electrode exhibits a Nernstian slope of 28.9±0.4 mV per decade for SO42− ion over a wide concentration range from 1.5×10−6−4.8×10−2 M, with a detection limit of 9.0×10−7 M. The CPE electrode manifested advantages of relatively fast response time, suitable reproducibility and life time and, most important, good potentiometric selectivity relative to a wide variety of other common inorganic anions. The potentiometric response of the electrode is independent of the pH of the test solution in the pH range 4.0–9.0. The proposed electrode was used as an indicator electrode in potentiometric titration of sulfate with Ba2+ ion, the determination of zinc in zinc sulfate tablet and also determination of sulfate content of a mineral water sample.
Electrocatalytic Dioxygen Reduction at Glassy Carbon Electrode Modified with Polyaniline Grafted Multiwall Carbon Nanotube Film
Authors: Manesh Kalayil Manian , Santhosh Padmanabhan , Gopalan Anantha Iyengar , Lee Kwang‐Pill
Published: July 2006

The work details the electrocatalysis of oxygen reduction reaction (ORR) in 0.5 M H2SO4 medium on a modified electrode containing a film of polyaniline (PANI) grafted multi‐wall carbon nanotube (MWNT) over the surface of glassy carbon electrode. We have fabricated a novel modified electrode in which conducting polymer is present as connected unit to MWNT. The GC/PANI‐g‐MWNT modified electrode (ME) is fabricated by electrochemical polymerization of a mixture of amine functionalized MWNT and aniline with GC as working electrode. Cyclic voltammetry and amperometry are used to demonstrate the electrocatalytic activity of the GC/PANI‐g‐MWNT‐ME. The GC/PANI‐g‐MWNT‐ME exhibits remarkable electrocatalytic activity for ORR. A more positive onset potential and higher catalytic current for ORR are striking features of GC/PANI‐g‐MWNT‐ME. Rapid and high sensitivity of GC/PANI‐g‐MWNT‐ME to ORR are evident from the higher rate constant (7.92×102 M−1 s−1) value for the reduction process. Double potential chronoamperometry and rotating disk and rotating ring‐disk electrode (RRDE) experiments are employed to investigate the kinetic parameters of ORR at this electrode. Results from RDE and RRDE voltammetry demonstrate the involvement of two electron transfer in oxygen reduction to form hydrogen peroxide in acidic media.
Chemical Reactivity of Polypyrrole and Its Relevance to Polypyrrole Based Electrochemical Sensors
Authors: Maksymiuk Krzysztof
Published: July 2006

One of the most frequently used conducting polymers, polypyrrole, can take part in chemical processes with typical components of ambient media: oxygen, acids, bases, redox reactants, water, and organic vapors; it can also incorporate nonreactive ions and surfactants from solutions. The influence of such processes on changes of the polymer structure, composition and on possible degradation is analyzed. The benefits and disadvantages of such processes for analytical characteristic of polypyrrole based electrochemical sensors are considered. This discussion is focused on potentiometric ion sensors, where polypyrrole is either a receptor membrane or an ion‐to‐electron transducer placed between a solid state electrode support and a typical ion‐selective membrane.
Reversibility of hepatic fibrosis in treated genetic hemochromatosis: A study of 36 cases
Authors: Falize Ludivine , Guillygomarc'h Anne , Perrin Michele , Lainé Fabrice , Guyader Dominique , Brissot Pierre , Turlin Bruno , Deugnier Yves
Published: July 2006

The current study was undertaken to assess whether fibrosis could regress under venesection therapy in patients with C282Y homozygous genetic hemochromatosis. The 36 patients studied were recruited from a subfile of our database consisting of 125 C282Y homozygotes with either severe fibrosis or cirrhosis (F3 or F4 fibrosis stage, respectively, according to the METAVIR grading system). The second liver biopsy was performed for management of liver cancer, extrahepatic surgery, or assessment of liver fibrosis. All paired biopsies were reviewed by two pathologists without knowledge of clinical data. Among the 13 patients who had F3 fibrosis on their initial liver biopsy, 3 had F0, 6 had F1, and 2 had F2 on their second liver biopsy. Among the 23 patients with cirrhosis on their initial liver biopsy, 1 had F0, 4 had F1, 3 had F2, and 2 had F3 on their second liver biopsy. When defining regression of fibrosis as a decrease of at least 2 METAVIR units, fibrosis regressed in 9 of 13 (69%) F3 and in 8 of 23 (35%) F4. When the ratio of gammaglobulins (g/L) to (platelets [n/mm3] × prothrombin activity [%]) was greater than 7.5, fibrosis never regressed.

In conclusion

, these data extend the concept of regression of fibrosis to patients with treated genetic hemochromatosis and suggest that some simple biochemical tests would be predictive of further regression of fibrosis as a result of venesection therapy. If confirmed on larger series, this could modify the ultrasound screening policy of hepatocellular carcinoma in genetic hemochromatosis.
Study Design for Assessing Species Environment Relationships and Developing Indicator Systems for Ecological Changesin Floodplains – The Approach of the RIVA Project
Authors: Henle Klaus , Dziock Frank , Foeckler Francis , Volker Klaus , Hüsing Volker , Hettrich Anke , Rink Marcus , Stab Sabine , Scholz Mathias
Published: July 2006

In this article the study design and data sampling of the RIVA project – “Development and Testing of a Robust Indicator System for Ecological Changes in Floodplain Systems” – are described. The project was set up to improve existing approaches to study species environment relationships as a basis for the development of indicator systems and predictive models. Periodically flooded grassland was used as a model system. It is agriculturally used at a level of intermediate intensity and is the major habitat type along the Middle Elbe, Germany. We chose a main study area to analyse species environment relationships and two reference sites for testing the transferability of the results. Using a stratified random sampling scheme, we distributed 36 study plots across the main study site and 12 plots each within the reference sites. In each of the study plots, hydrological and soil variables were measured and plants, molluscs, and carabid beetles were sampled. Hoverflies were collected on a subset of the sampling plots. A brief summary of first results is then provided. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Laminin peptide‐conjugated chitosan membrane: Application for keratinocyte delivery in wounded skin
Authors: Ikemoto Shigehiro , Mochizuki Mayumi , Yamada Masanori , Takeda Akira , Uchinuma Eiju , Yamashina Shohei , Nomizu Motoyoshi , Kadoya Yuichi
Published: July 2006

Tissue engineering requires the delivery and survival of cells to organ sites needing repair. Previously, we showed that an active laminin peptide (AG73: RKR‐LQVQLSIRT)‐conjugated chitosan membrane promoted cell adhesion and spreading in vitro. Here, we seeded human keratinocytes onto AG73‐chitosan membranes and found that nearly 80% of the cells were attached to the membranes within 2 h. The membranes carrying the keratinocytes were inverted and placed onto exposed muscle fascia on the backs of nude mice. After 3 days, the keratinocytes had migrated from the membrane and established a stratified epidermis‐like structure on the fascia. Cells recognize the AG73 through transmembrane proteoglycan syndecans, which recognition system has not previously been tested in tissue engineering applications. We suggest that the AG73‐chitosan membrane is useful as a therapeutic formulation and is applicable as a cell delivery system such as delivering keratinocytes to a wound bed. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Preparation of bioactive nanotitania ceramics with biomechanical compatibility
Authors: Yang B. C. , Yu Q. F. , Li Z. S. , Qu Y. , Huang Y. , Chen J. Y. , Gu Z. W. , Zhang X. D.
Published: July 2006

In this article, bioactive nanotitania ceramics with biomechanical compatibility was prepared by using an additive of hydroxyapatite or MgO as particle growth inhibitor. After sintering at 1000°C, the particle size of nanotitania ceramics prepared by using HA as additive (HT) was much smaller than that prepared by using MgO as additive (MT). In simulated body fluid (SBF), HT could induce apatite formation in 4 days, while no apatite could be found on MT even after it was soaked in SBF for 14 days. After Ros17/28 osteoblasts were cultured on the materials for 1, 4, and 6 days, MTT results showed that the osteoblasts on the HT differentiated faster than that on the MT. Mechanical tests results showed that the bending and compressive strength of HT were 160 and 200 MPa, while those of MT were 70 and 88 MPa, respectively. These results demonstrated that it is suitable to prepare bioactive nanotitania ceramics, with biomechanical compatibility, by using HA as particle growth inhibitor. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Synthetic lubricants and their industrial applications
Authors: Miller J. William
Published: July 2006

Production of many synthetic lubricants starts with base stocks which are syntbesised from high volume hydrocarbon intermediates. For example, polyalphaolefin base fluids are synthesised from ethylene. Some, however, start with very basic raw materials. for example, silicone base fluids are made from sand (SiO2), require considerable energy, and there are many steps in their manufacture including handling of very corrosive materials. These variable manufacturing requirements account for the broad price range for synthetics and the much higher price for the ‘exotics’ such as fluorosilicones. Unlike mineral oil base stocks, which are a complex mixture of naturally‐occurring hydrocarbons refined from crude oil, synthetic base stocks are man‐made, having controlled molecular structure with predictable properties. As with all present‐day fluid lubricants, synthetics are formulated by combining the base stocks with selected additives.
Nonflammable hydraulic system development for aerospace
Authors: Snyder Carl E. , Gschwender Lois J.
Published: July 2006

In 1975, the Air Force Laboratories were directed to evaluate ways to eliminate United States Air Force hydraulic fluid fires. This paper describes the approach selected: the development of a hydraulic fluid which would be totally nonflammable to any current or anticipated aircraft hydraulic fire ignition source. Flammability test criteria were established. Selection and optimisation of a suitable base stock, fluid characterisation and formulation efforts are presented.
A laboratory evaluation of partial synthetic automatic transmission fluids
Authors: Willermet P. A. , Haakana C. C. , Sever A. W.
Published: July 2006

Blending synthetic fluids with conventional base stocks gave large reductions in low temperature viscosity without appreciable reductions in high temperature viscosity or deterioration in properties such as volatility or flash point. Ten percent blends of a polyalpbaolefin or an ester synthetic reduced the viscosity at — 27.9°C by approximately 50%. These blends gave improved oxidation stability as measured by the Aluminum Beaker Oxidation Test, but poorer antiwear performance as measured by the Four Ball Test. The latter result indicated that the antiwear additive package should be optimised to accommodate composition differences between conventional fluids and conventional/synthetic blends.
Arylalkoxysilanes as synthetic lubricants
Authors: Sasín M. , Čermák J. , Kolář D. , Dobeš P.
Published: July 2006

An earlier paper1 reported experimental data for a group of silicon compounds examined in comparison with other materials normally used as bases for synthetic lubricants. Here, a furthergroup of organo‐silicon compounds are examined and their properties given. Readers are referred back to the original paper appearing in JSL Volume 1 Number 2 July 1984 for background and comparative material.
Formulating advanced 4 centistoke gas turbine oils ‐ a feasibility study
Authors: Thompson Q. E. , Zielinski R. E.
Published: July 2006

A formulation study has been carried out to assess the feasibility of developing advanced gas turbine lubricants in the (4 cSt) viscosity range intermediate between current MIL‐L‐7808 and MIL‐L‐23699 lubricants. Using additive technology developed on advanced MIL‐L‐2 7502 oils the authors have formulated several 4 cSt polyol ester base stocks. Eight of the blends thus far tested have shown good to acceptable performance in the Erdco Bearing Rig Test run under MIL‐L‐27502 conditions. Various other key targets of a proposed new specification have been met or closely approached.
A study of the potential benefits associated with the development of a dedicated helicopter transmission lubricant
Authors: Drago R. J. , Mangione P. J. , Wendrzycki R. D.
Published: July 2006

A common oil is now used in both the engines and transmissions of virtually all US military helicopters. While this provides significant logistic advantages, these advantages are attained only by compromising the optimisation of the oil for either system. This paper summarises the results of two studies undertaken to determine what benefits would accrue through the development of a special oil tailored specifically to meet the unique requirements of high‐speed, heavily loaded helicopter transmission systems. These studies, conducted independently by two major helicopter manufacturers under the direction of the US Naval Air Propulsion Center, addressed specific problem areas as related to typical production aircraft in order to reach well‐documented conclusions. In addition, the effect of the availability of such a special gearbox lubricant on the development of other advanced‐technology components was evaluated and documented.
Laboratory parameters for high water based hydraulic fluid testing
Authors: Hughes D. G. , Forsberg J. W.
Published: July 2006

A review of the composition and properties of current water‐containing hydraulic fluids leads to the conclusion that current technology could be improved towards a high water containing fluid with good antiwear, low toxicity and high fire resistance characteristics. A modified pump test was used based on ASTM D2882, using a Vickers V105C apparatus. Wear rate data is presented for various candidate fluids including a full synthetic, showing differences between HFA, HFB, HFC and HWBF and looking at variations in break‐in wear and subsequent wear behaviour. Data is also presented for candidate fluids tested in industrial‐type hydraulic pumps, and illustrates the role of viscometric properties including shear stability.
A practical investigation of wear in piston pumps operated with HFA fluids with different additives
Authors: Janko K.
Published: July 2006

This paper examines the use of water‐based hydraulic fluids in hydraulic pumps, Four different types of HFA fluid are reviewed in terms of properties and usage. In a research programme, two principal fluids, a HFA micro emulsion and a HFA solution, were evaluated in relation to their wear protection capability in a short‐term test procedure, and their operational behaviour and confirmation of the short‐term test procedure in a long‐term test. The differences between the fluids are mainly in terms of wear of the test pumps. It is concluded that a performance standard similar to oil‐based fluids has not yet been reached.
High temperature greases based on polyurea gellants: A review
Authors: Venkataramani P. S. , Srivastava R. G. , Gupta S. K.
Published: July 2006

There is increasing demand for high temperature greases capable of operating in the range of 175–235°C. In this paper, one type of grease, polyurea, is described, and its preparation given, in terms of raw materials, temperature, solvents, base fluids including synthetics, catalysts, additives and thickeners. Two typical preparation procedures are described. The properties of polyurea greases are then reviewed, with detailed tabular matter given.
Effects of cutting fluids on drilling aluminium casting alloy 390
Authors: Leep Herman R. , Sims Robin W.
Published: July 2006

The primary objective of this research project was to compare the tool wear resulting when a semi‐synthetic cutting fluid was used, to that from use of a premium soluble oil. The secondary objective was to determine the effects of cutting speed, drill diameter, and fluid concentration, on tool wear.

The experiments contained two key elements: (1) cast aluminium alloy 390 was used as the workpiece material and (2) deep‐hole drilling to a depth greater than two diameters was performed. Numerous drilling tests were performed with each cutting fluid using a flood application. To meet the primary objective, an experiment was designed for each cutting fluid and the wear on the lands of twist drills was measured. The secondary objective utilized a statistically‐designed 23 factorial experiment which evaluated the effects that moderate and relatively high cutting speeds, two drill diameters, and two levels of fluid concentration, had on tool wear.

After analysis of the test results, it was concluded that concentration had the most significant effect on land wear when the experimentally‐formulated semi‐synthetic cutting fluid was used. Cutting speed was the most significant factor when drilling with the commercially‐available premium soluble oil. Tool wear while using the semi‐synthetic fluid was slightly less than that for the premium soluble oil.
The lubrication of plastics by perfluoropolyether fluids
Authors: Anderson J. C. , Flabbi L. , Caporiccio G.
Published: July 2006

The work reported here demonstrates that very small quantities of perfluoropolyether fluids will provide effective boundary lubrication for a number of plastics materials. This includes plastics which are known to benefit from trace quantities of lubricants, as well as high‐temperature plastics, where a reduction of two orders of magnitude in wear rate can be achieved at temperatures up to 200°C. Direct application of fluid to the plastics surfaces appears to give better results than impregnation into a porous plastic. The effect of counterface roughness and bearing pressure on wear performance is also discussed.
Synthesis, evaluation and applications of complex esters as lubricants: A basic study
Authors: Venkataramani P. S. , Kalra S. L. , Raman S. V. , Srivastava H. C.
Published: July 2006

This paper reports the synthesis of various complex esters, describing their physical, chemical, and tribological properties. Specifically, an attempt is made to study the effects of changing the central polyol backbone, of varying chain length of diacids, and of different endcapping alcohols on various properties.
Performance comparisons of synthetic and mineral oil crankcase lubricant base stocks
Authors: Ripple D. E. , Fuhrmann J. F.
Published: July 2006

The physical and performance characteristics of representative synthetic base stocks are compared with those of mineral oils. Comparisons of the base stocks alone and as fully formulated crankcase lubricants are presented.

Bench test results and physical properties of unformulated synthetic and mineral oil base stocks are compared. The volatility characteristics of synthetic base stocks are superior to typical mineral oil base stocks. All the synthetic base stocks displayed greater viscosity indices than did mineral oils. Bench tests designed to measure thermal and oxidative stabilities are used to compare synthetic with mineral oil base stocks. Although synthetics appeared no more resistant to oxidation than did mineral oils, fewer sediments, deposits and fluid viscosity increases were observed with synthetic base stocks. No one type of synthetic base oil showed a distinct advantage in these evaluations.

Fully formulated mineral oil‐based lubricants are compared with commonly used synthetic‐based lubricants containing identical additive treatments. The synthetic lubricants showed superior engine cleanliness, and resistance to viscosity increased in these tests, but were directionally less effective in wear prevention than mineral oil‐based lubricants. Proper formulation or addition of an antiwear supplement overcame this deficiency.

These comparisons demonstrated that synthetic base stocks are available with a wide range of physical properties. Available synthetic base stocks offer performance advantages at an increased cost over mineral oils, but proper formulation of the synthetic lubricant is necessary to ensure totally acceptable lubricant performance.
Rotary‐vane compressors: Some technical aspects of long‐life lubricants
Authors: Légeron J.‐P. , Beslin L.
Published: July 2006

Compressors are used all over the world for various individual applications; the current application concerns their use in the ozone process of water treatment. Technical data on different mineral and synthetic lubricants are given. In particular, a new oil was chosen for investigation. Field testing was undertaken over more than 6000 h on two different locations. Used oil monitoring was conducted by sampling during the experiment; analyses of physical and chemical parameters were made and their kinetics are described. Wear, viscometrics and ozone process interaction are discussed in this study.
Development of a soluble lubricity additive for perfluoropolyalkylether fluids
Authors: Sharma Sashi K. , Gschwender Lois J. , Snyder Carl E.
Published: July 2006

A new lubricity additive for perfluoropolyalkylether (PFPAE) fluids was synthesized. A linear, unbranched fluid formulated with this additive was evaluated under boundary lubrication and elastohydrodynamic (EHD) lubrications. Performance of the base fluid imporved significantly with the incorporation of this additive.
Influence of the type and concentration of synthetic components in motor oil formulations
Authors: Camera F. , Huby F.
Published: July 2006

A sixteen‐test experimental design has been used to evaluate the influence offive factors which are of primary importance when formulating a semisynthetic engine oil. These are the package composition, the Viscosity Index Improver (VII) chemistry, the total synthetic concentration, the PAO‐to‐ester ratio and the origin of the ester.

The subjects of interest in this work were the composition of the final formulation (percentage of Viscosity Index Improver, base oil balance, etc.) and the results of the sixteen formulations in laboratory screening tests for volatility, dispersancy, oxidation and detergency.
Viscosity — temperature relationship of alphaolefin oligomers/polyalphaolefins
Authors: Kotas Jan
Published: July 2006

For the liquid products of the oligomerisation of C3‐C12 alphaolefins the values of poles of the Walther viscosity dependencies have been found to be a function of monomer size and oligomerisation initiation system. In this paper some new relationships are described that have been found between the value of kinematic viscosity and average number molecular weight. These dependencies allow definition of the functional relationship between kinematic viscosity, size and structure of oligomer and temperature; a program can be written for rapid and sufficiently precise determination of viscosity‐temperature dependencies and average number molecular weights, both for fractions and for mixtures of alphaolefin oligomers.
Some testing criteria for antiwear and antifriction properties of synthetic fluids
Authors: Korycki J. , Wiślicki B.
Published: July 2006

Friction test results for selected properties of lubricating fluids including carboxylic acid esters, phosphate esters and polyglycol water solutions are presented, which indicate that results obtained in a modified four‐ball tester can change with time spent under load. A variety of conditions and materials were tested.
The characterisation of synthetic lubricant formulations by field desorption mass spectrometry
Authors: Rollins K. , Taylor M. , Scrives J. H. , Robertson A. , Major H.
Published: July 2006

Field desorption ‐ mass spectrometry (FD‐MS) was evaluated as a tool for characterisation of the complex mixtures of compounds typical of synthetic lubricants. The lubricants were initially screened using field ionisation, then tested samples were subjected to field desorption. Results are presented for various formulations for an ester, an ester‐synthetic oil mixture, polyisobutylenes, PAO additives, and a fully formulated oil.
High‐performance ester‐based two‐stroke engine oils
Authors: Kenbeek D. , van der Waal G.
Published: July 2006

As lubricant classification of different types of two‐stroke oil moves towards realisation, the need has emerged for environmentally friendly two‐stroke lubricants suitable for different operating conditions and applications. In this paper the authors report results on ester‐based synthetic lubricants according to various test regimes, and show the superiority of synthetics in these tests. Outboard and chainsaw 2T lubricants are discussed.
A study of high‐boiling alkylbenzene fractions as synthetic lubricants for refrigerators
Authors: Yotov St. , Antonov C. , Alexandrov V. , Hinkova M. , Ivanov S.
Published: July 2006

The properties of synthetic oils based on high‐boiling alkylbenzenes ‐ good low temperature behaviour, thermo‐oxidative, anticorrosive and hydrolylic stability, make them suitable candidates as lubricating oils for refrigerator machinery. This paper reports the results of investigations by column adrorption chromatography and GC‐MS into the nature and properties of three high boiling alkylbenzene fractions, and their behaviour when compounded into candidate refrigerator oils.
Effects of kinds of oil on power transmission: Efficiency of planetary traction drives
Authors: Ishibashi A. , Sonoda K.
Published: July 2006

One of the most interesting problems in traction drives is the analysis of their power transmission efficiency. Using an experimental two‐disk machine and two planetary traction drives, together with fourteen test oils, it is shown that the power transmission efficiency can increase up to 97% in the case of an experimental planetary traction drive. The synthetic traction oils bring about a lower efficiency than mineral oils when the output torque is small. This is ascribed to their higher traction coefficients which cause larger friction in the rolling bearings which support the rolling elements.
High‐temperature hydraulic fluids
Authors: Gschwender L. J. , Snyder C. E.
Published: July 2006

The rationale is presented for the development of 315 °C bulk oil high‐temperature hydraulic fluids for future US Air Force systems. Four chemical classes of candidate fluids worthy of consideration are described along with their relative merits and limitations. The four fluids are: mineral oil based MIL‐H‐ 27601A, a synthetic hydrogenated polyalphaolefin, a synthetic silahydrocarbon (tetra alkyl silane), and a linear perjluoropolyalkylether. Questions for consideration in selecting a candidate high‐temperature hydraulic fluid are presented and discussed in relation to the intended specific application.
Influence of the size, geometry, and material of the rollers on EHD traction
Authors: Muraki M. , Sakaguchi K.
Published: July 2006

The influence of the parameters relating to the rolling elements on traction in EHD contacts is experimentally studied on a two‐roller machine, in which experiments with point contacts are conducted for two paraffinic mineral oils, a synthetic naphthene, and a synthetic ester. Firstly, it is shown that the same traction curves are obtained in both internal and external contacts when the effective radius in rolling direction of the rollers is equal. The effect of an increase in the size of the rollers is to increase the film thickness and this results in a gentle decline in the maximum traction coefficient. As the effective radius in transverse direction is increased, so the traction decreases for a paraffinic mineral oil, while that for a synthetic naphthene remains constant independent of the geometry of the rollers. Finally, the effect of the material of the rollers is studied, employing rollers made of steel, ceramics, phosphorus bronze, brass, and aluminium alloy. The traction obtained under an identical normal load can be arranged according to the effective elastic modulus of the rollers for each oil. However, under identical contact pressure the same maximum traction curve is obtained independent of the material, but the decline in traction in the thermal region is slightly steeper with the ceramic than with the steel rollers because of the difference in the temperature rise of the fluid film.
Fractionation of oligomers of linear alphaolefins in a molecular evaporator
Authors: Cvengroš Ján , Kotas Jan
Published: July 2006

Oligomers of higher alphaolefins, mainly of 1‐decene and 1‐octene have important applications as synthetic lubricating oils or their components. The results of fractionation of polydecene, polyoctene, and polybutene oils in a wiped‐film molecular evaporator, for the purpose of preparing narrow distillate cuts, are presented in the paper. Characteristics and properties of the fractions obtained are shown, and the possibilities for this distillation method in the fractionation of polyolefin oils discussed.
Wear and friction of filled polyamide coatings
Authors: Ali Waheed Yosry
Published: July 2006

The aim of this article is to report wear and friction studies of cylindrical test steel pins coated with polyamide (PA6) incorporating fillers (iron, copper, aluminium, tin, lead) and solid lubricants (graphite, molybdenum disulphide (MoS2)) to improve the mechanical, thermal, and frictional properties of polyamide (PA6). The coated testpins were loaded against a rotating cylinder of bearing steel in dry, lubricated, abrasive conditions at constant load and sliding speed. The test results show a significant reduction in wear and friction for both copper‐filled polyamides and lead‐filled polyamides.
The film‐forming properties of polyalkylene glycols
Authors: Aderi M. E. , Johnsto G. J. , Spikes H. A. , Balson T. G. , Emery M. G.
Published: July 2006

It is now recognised that, for many practical applications, an important property of a lubricant is its ability to generate thick, elastohydrodynamic (EHD) films in concentrated contacts. This paper describes a study of the EHD film‐ forming properties of polyalkylenie glycol lubricants. A wide range of polyglycol structures have been examined, with different monomer types, initiators, and molecular weights. Film thickness has been measured at several different temperatures using both conventional and ultra‐thin film interferometry. From the measured film thicknesses, the effective pressure–viscosity coefficients of the lubricants have been evaluated. This has enabled a systematic investigation of the effect of polyalkylene glycol structure on both pressure–viscosity coefficient and EHD film formation.
Friction and wear of copper/lead and aluminium/tin filled polyamide coatings
Authors: Ali Waheed Yosry
Published: July 2006

The friction and wear of steel pins coated with filled polyamides and loaded against a rotating cylinder of bearing steel were tested under dry, lubricated, and abrasive contaminated conditions. The filler materials were copper/lead and aluminium/tin powders.

The test results show a significant reduction in friction with the Cu/Pb filled polyamides (8 wt.% Cu, 12 wt.% Pb, and 80 wt.% PA6). The Al/Sn filled polyamides (3 wt.% Al, 2 wt.% Sn, and 95 wt.% PA6) showed the best wear resistance, accompanied by an increase in the coefficient of friction.
Use of lubricants during cold rolling of aluminium
Authors: Zhang S. , Lenard J. G.
Published: July 2006

Natural and synthetic lubricants specially formulated for cold rolling of aluminium were evaluated in terms of their ability to lower mill loads. The use of additives was also studied. Roll separating forces and roll torques were monitored. No significant differences between natural and synthetic oils were observed. The ability to maintain lubricant action was found to be lowest when synthetic esters were present, either in the base oil or as an additive.
Polymer esters and their synergy with ZDDP – the possibility of reducing ZDDP content in lubricants
Authors: Wallfahrer U.
Published: July 2006

In recent years, environmental awareness and legislation have enforced ever greater controls on the emissions of motor vehicles. To meet those requirements, the increased use of exhaust port catalysts is almost inevitable. However, there are concerns that lubricant‐derived phosphorus compounds could in the long term be detrimental to those catalysts and make it necessary to reduce the W D P level in the lubricating oils.

Laboratory bench tests and engine rig tests show that a significant reduction of the level of ZDDP may be possible in the presence of a special class of polymer esters without reducing the wear performance of the engine oils.
Performance of fluid and solid lubricants in spacecraft applications
Authors: Fleischauer Paul D.
Published: July 2006

Results of a series of lubricant screening and performance tests are described that provide criteria for the selection of proper Lubrication for precision spacecraft mechanisms, such as reaction wheels, gyroscopes, solar array drives, and gimbals. An eccentric, thrust—bearing apparatus was used for rapid screening and relative ranking of lubricants, and results are compared to life test data for a series of oils. Synthetic hydrocarbon oils and greases are recommended for the first three types of mechanism, while newly developed, high density, oriented, MoS2, films are recommended for gimbals.
High‐temperature tribology of future diesel engines
Authors: Kamo Roy , Bryzik Walter
Published: July 2006

Future diesel engines will be operated at higher cycle temperatures. These higher cycle temperatures will invariably pose tribological problems of the top ring, piston, valve seats, and valve guides. Current lubricating oil with a thermal oxidative stability up to 204°C will be inadequate: polyol ester‐base formulated synthetic oil, such as Stauffer Chemical SDL‐1 or US TACOM MRI‐1, with 310°C thermal oxidative stability could possibly be the next generation of lubricating oil.

However, as we get nearer to the time when diesel engines will be constructed in advanced structural ceramics or composites for ‘adiabatic’operation, the thermal stability of the lubricating oil will have to approach 445°C.

To withstand a top ring reversal temperature beyond 310°C, polyphenyl ether base oil and other high‐temperature liquid lubricants are sought, but the highly aromatic polyphenyl ether type oil has thus far shown little promise for this application. The hybrid piston with solid lubricated top ring has potential. Densified Cr2O3 on Cr2O3 has demonstrated the possibility of operating at 380°C top ring reversal temperature, with acceptable wear and life. NASA PS212 with Stellite 6B has also been tested without a liquid lubricant.

The tribological needs of the next generation of high‐output, high‐temperature diesel engines can therefore be met with the synthetic polyol ester base, cost‐effective, formulated lubricant. The adiabatic ceramic engine will require much higher temperature capability. To this end, tribologists will have to direct their efforts to other higher temperature liquid lubricants and to solid lubricants. A laboratory coefficient of friction of < 0.06 must be achieved in order to maintain acceptable brake‐specific fuel consumption. This target is based on cast iron on cast iron with lubricating oil, and it must be achieved with acceptable wear and cost.
Biodegradability of lubricant base stocks and fully formulated products
Authors: Völtz Martin , Yates Neil C. , Gegner Eberhard
Published: July 2006

Increasing awareness of the environmental impact of consumer and industrial products has produced a demand for lubricants that biodegrade. There is a number of biodegradation tests that can be used on lubricants, although not all are always appropriate, as this paper explains. The CEC test is among the best known and is in use for both conventional and synthetic oils. There will, in future, be a greater movement to biodegradable oils in Europe, perhaps extending to all oils.
Assessment of the biodegradability of mineral oil and synthetic ester base stocks, using CO2 ultimate biodegradability tests and CEC‐L‐33‐T‐82
Authors: Novick N. J. , Mehta P. G. , McGoldrick P. B.
Published: July 2006

The EPA (Gledhill) Shake Flask test, OECD Modified Sturm test, and CEC (CEC‐L‐33‐T‐82) Biodegradability test have been used to assess the degradability of mineral oil, natural ester, and synthetic ester base stocks. The Shake and Sturm tests are ultimate biodegradability tests which determine the percentage of test material carbon converted to CO2 over a 28‐day period; the CEC test determines, at 21 days, the disappearance of the carbon‐hydrogen stretch in Freon extracts of the test medium. In all three tests, the test material is added to a mineral salts medium, the medium is inoculated with mixed liquor from a municipal waste water treatment plant and test flasks are shaken. The Shake Flask and CEC tests were able to show expected differences in degradability between paraffinic and naphthenic mineral oils. A poor correlation was found between ultimate biodegradability test results and results from the CEC test when synthetic esters were studied. Dissolved organic carbon (DOC) analysis of the test medium indicated that degradation of some synthetic esters led to the accumulation of water‐soluble metabolites which are not extractable into Freon, as required for quantification by the CEC test. Thus, while the CO2 tests detected differences in the degradability of these test materials, the CEC test did not. The CEC test can, therefore, overestimate degradability of some synthetic esters, leading to the erroneous conclusion that these materials would meet OECD Ready Biodegradability criteria. Biodegradability results for the EPA, OECD, and CEC tests are presented and results compared.
Tribological properties of some water‐based lubricants containing polyethylene glycol under boundary lubrication conditions
Authors: Yong Wan , Qunji Xue , Lili Cao
Published: July 2006

The metal‐working industry is increasingly interested in synthetic metalworking fluids and coolants. The excellent lubricating properties of polyalkylene glycols have been recognised in areas such as gear lubricants, hydraulic fluids, and compressor lubricants. The main purpose of the present work was to investigate the friction and wear properties of several polyethylene glycols and their synergy with a common water‐soluble EP additive, using four‐ball and ball‐on‐plate tribometers.
Polysiloxane substituent influence on the foaming of polyolesters and polyolester turbine engine lubricants
Authors: Centers Phillip W.
Published: July 2006

Parts‐per‐million (ppm) quantities of polysiloxanes with different molecular structures have varying effects on the foaminess of a polyolester, trimethylolpropaneheptanoate (TMPH), and a formulated synthetic polyolester gas turbine engine lubricant. At the 100 ppm concentration evaluated in a standard foam test, TMPH‐polysiloxane mixtures that exhibit lower interfacial surface tension produced copious quantities of foam. Estimates of Lewis acid‐base interaction and solubility of the additive in the polyolester are not helpful in predicting foaminess. Consideration of additive polymeric structure, the potential for increased additive molecular entanglement due to substituent length, and interaction of adjacent polysiloxane molecules at the surface, are helpful in rationalising differences observed in foaming. Some lubricant additives, such as antioxidants and antiwear agents, appear to enhance the profoamant tendencies of selected polysiloxanes.
Ecological and health aspects of metalworking fluids' manufacture and use
Authors: Balulescu Margareta , Herdan J. M.
Published: July 2006

The manufacture, use, and disposal of metalworking products are reviewed in the light of modern health and environmental considerations, and new stricter legislation, notably in Europe. Some new vegetable oil based formulations, which meet the new criteria, are presented.
Advanced lubricants for heat engines
Authors: Hsu S. M. , Perez J. M. , Ku C. S.
Published: July 2006

An advanced liquid lubricant for heat engines has been developed and tested successfully in a prototype engine. The lubricant possesses superior oxidation stability and high temperature stability. With the advent of new engine designs, stability should be measured in terms of both the temperature and the time for which the lubricant is subjected to it. This lubricant is designed to provide friction and wear protection for three to five minutes at 425°C (800°F) at the ring zone and maintains stability at an oil sump temperature of 171°C. The lubricant has been evaluated by the Cummins Engine Company. Out of a field of several dozen lubricants, six lubricants were selected for a prototype 200 h endurance tests. The NIST lubricant was one of the two lubricants that successfully finished the endurance testing. This paper provides an overview of the key lubricant design considerations, including oxidation and thermal stability, volatility, and deposit control, the prototype engine test conditions and the results.
Diversification of automatic transmission fluid technology
Authors: Fewkes Roy , Hughes David G. , Joseph Ivan E. , Sumieski James L.
Published: July 2006

A range of commercially available automatic transmission fluids (ATFs) was tested, in order to compare their performance both with each other and with broadly accepted European market requirements. The test results showed a considerable variance in the performance of the fluids, despite their conformity to a common ATF specification. Furthermore, when the latest transmission developments are considered, it becomes clear there is, in many instances, a divergence of performance requirements. One area of potential conflict is the different emphasis on passenger cars as against commercial vehicles in the North American and European markets. The paper examines factors that influence ATF performance requirements, and the areas of compromise if a common fluid is needed. Suggestions are made to address those circumstances where it seems that performance needs are too divergent.
The application of matrix‐assisted laser desorption/lonisation time‐of‐flight mass spectrometry (MALDI‐TOF MS) to the analysis of lubricants. part 1. polyol ester aviation turbine engine oils
Authors: Bartl P. , Völkl Ch.
Published: July 2006

In the present work, Matrix‐Assisted Laser Desorption/lonisation Time‐of‐Flight Mass Spectrometry (MALDI‐TOFMS) is demonstrated to be a valuable method for the analysis of synthetic polyol ester turbine engine oils. A softionisation technique, it generates, under adequate experimental conditions only, (quasi‐)molecular ions and allows detection and identification of all components including di‐ and tripentaerythritol esters and oligomeric additives, without pre‐separation.
Lubrication by bionic synovial fluids in the human urinary system
Authors: Dehua Tao , Wanqi Yan , Guoqing Xie
Published: July 2006

The patient suffers a lot when cystoscopes or catheters are inserted into the urinary system. In order to lower friction whilst being non‐poisonous, nonfungoid, and meeting other medical requirements, a new bionic medical lubricant has been synthesised. In tests imitating the friction condition between skin and plastic apparatus, eel fish synovia, white oil, glycerol, polyethylene glycol in aqueous solution, Tween‐80, a proprietary medical lubricant, and the candidate fluid were tested. The results of these tests demonstrated that the synthesised lubricant performs best, with eel fish synovia second, and glycerol last.

The test fluid has been trialled in some key hospitals (Shanghai, Beijing, Guangzhou, and Shijia Zhuang), and the results showed that about 95% of patients experienced no pain, and about 5% had a slight feeling, with no reported discomfort. The candidate bionic medical lubricant is in use by doctors in medical practice.
A tribological study of an S,P‐containing benzotriazole derivative as an additive in pentaerythritol ester
Authors: Tianhui Ren , Jian Xia , Longzhen Zheng
Published: July 2006

The load‐carrying capacity, antiwear and friction reduction properties of an S,P‐containing benzotriazole derivative (BMDDP) added to a synthetic lubricant (pentaerythritol ester) were evaluated using a four‐ball test machine. The results when compared with those of tricresyl phosphate (TCP) and zinc dialkyldithiophosphate (ZDDP) show that, in pentaerythritol ester, the novel compound (BMDDP) is an excellent multifunctional additive, which possesses better load‐carrying capacity, antiwear and friction reduction properties than either TCP or ZDDP. The rubbed surfaces were analysed using XPS and EPMA, and the antiwear mechanism is discussed.
On the effects of friction on free volume holes in PTFE
Authors: Qunji Xue , Feng‐Yuan Yan
Published: July 2006

Since the macroscopic properties of materials are relevant to their micro structure, the detection of microscopic defects or their changes in size and concentration is an interesting topic in materials science. The positron annihilation lifetime (PAL) method used here is established as a unique technique that can provide information about the size and concentration of free volume holes directly without significantly intervening in the bulk properties of the specimens. To our knowledge, this is the first time that PAL techniques have been used to study the wear mechanism of macromolecular tribomaterials. Here we present the results of a study in which the correlation between the fretting wear behaviour of polytetrafluorethylene (PTFE) and the changes in its free volume size and concentration in amorphous‐crystal interface regions was found to be δω =A.δτ3, where δω is the wear loss of PTFE under fretting wear conditions, A is a constant, and δτ3 represents the relative change in the third lifetime components after the friction test. The results indicate that fretting mainly influences the characteristics of atomic‐scale free volume holes in the amorphous‐crystal region in PTFE, and under high‐load fretting wear conditions the ductile polymer PTFE possesses a self‐curing function for its defect‐free micro volume holes.
Lubrication performance of model organic compounds in high oleic sunflower oil
Authors: Minami Ichiro , Hong Hyun‐Soo , Mathur Naresh C.
Published: July 2006

Genetically modified sunflower oil, so called ‘high oleic’ sunflower oil, is a promising and environmentally friendly fluid that possesses many advantages as a lubricating oil. It will be more usable if its performance as lubricating oil can be optimised by additives. In the present study, we have examined model friction modifiers under boundary lubrication conditions to understand their applicability to vegetable oils. Octadecanoic acid provides good lubricity. Octadecyl amine and octadecanamide are also acceptable, whereas octadecane thiol exhibits a negative effect on lubricity.
The application of Matrix‐Assisted Laser Desorption/Ionisation Time‐of‐Flight Mass Spectrometry (MALDI‐TOF MS) to the analysis of lubricants. Part 2. used polyol ester aviation turbine engine oils
Authors: Bartl P. , Völkl Chr. , Kaiser M.
Published: July 2006

In the present work, Matrix‐Assisted Laser Desorption/Ionisation Time‐of‐ Flight Mass Spectrometry (MALDI‐TOF MS) is demonstrated to be a valuable technique in the characterisation of used polyol ester oils, and one which includes details of the base‐oil and additive degradation chemistry. The results are confirmed by GC/MS and 13C‐NMR data.