Sample records for solid lubricants part

  1. Solid lubricants

    Sliney, Harold E.


    The state of knowledge of solid lubricants is reviewed. The results of research on solid lubricants from the 1940's to the present are presented from a historical perspective. Emphasis is placed largely, but not exclusively, on work performed at NASA Lewis Research Center with a natural focus on aerospace applications. However, because of the generic nature of the research, the information presented in this review is applicable to most areas where solid lubricant technology is useful.

  2. Solid lubricants and surfaces

    Braithwaite, E R


    Solid Lubricants and Surfaces deals with the theory and use of solid lubricants, particularly in colloidal form. Portions of this book are devoted to graphite and molybdenum disulfides, which are widely used solid lubricants in colloidal form. An extensive literature on the laboratory examination of hundreds of solids as potential lubricants is also provided in this text. Other topics discussed include the metals and solid lubricants; techniques for examining surfaces; other solid lubricants; metal shaping; and industrial uses of solid-lubricant dispersions. This publication is beneficial to e

  3. Solid Lubrication Fundamentals and Applications

    Miyoshi, Kazuhisa


    Solid Lubrication Fundamentals and Applications description of the adhesion, friction, abrasion, and wear behavior of solid film lubricants and related tribological materials, including diamond and diamond-like solid films. The book details the properties of solid surfaces, clean surfaces, and contaminated surfaces as well as discussing the structures and mechanical properties of natural and synthetic diamonds; chemical-vapor-deposited diamond film; surface design and engineering toward wear-resistant, self-lubricating diamond films and coatings. The author provides selection and design criteria as well as applications for synthetic and natural coatings in the commercial, industrial and aerospace industries..

  4. Lubrication of soft viscoelastic solids

    Pandey, Anupam; Venner, Kees; Snoeijer, Jacco


    Lubrication flows appear in many applications in engineering, biophysics, and in nature. Separation of surfaces and minimisation of friction and wear is achieved when the lubrication fluid builds up a lift force. In this paper we analyse soft lubricated contacts by treating the solid walls as viscoelastic: soft materials are typically not purely elastic, but dissipate energy under dynamical loading conditions. We present a method for viscoelastic lubrication and focus on three canonical examples, namely Kelvin-Voigt-, Standard Linear-, and Power Law-rheology. It is shown how the solid viscoelasticity affects the lubrication process when the timescale of loading becomes comparable to the rheological timescale. We derive asymptotic relations between lift force and sliding velocity, which give scaling laws that inherit a signature of the rheology. In all cases the lift is found to decrease with respect to purely elastic systems.

  5. Solid Lubricants for Oil-Free Turbomachinery

    DellaCorte, Christopher


    Recent breakthroughs in gas foil bearing solid lubricants and computer based modeling has enabled the development of revolulionary Oil-Free turbomachinery systems. These innovative new and solid lubricants at low speeds (start-up and shut down). Foil bearings are hydrodynamic, self acting fluid film bearings made from thin, flexible sheet metal foils. These thin foils trap a hydrodynamic lubricating air film between their surfaces and moving shaft surface. For low temperature applications, like ainrafl air cycle machines (ACM's), polymer coatings provide important solid lubrication during start-up and shut down prior to the development of the lubricating fluid film. The successful development of Oil-Free gas turbine engines requires bearings which can operate at much higher temperatures (greater than 300 C). To address this extreme solid lubrication need, NASA has invented a new family of compostie solid lubricant coatings, NASA PS300.

  6. Thermal stability of solid lubricant element MoS{sub 2} in injection molded parts of 17-4 PH stainless steel

    Furlan, K.P.; Binder, C.; Klein, A.N., E-mail:, E-mail:, E-mail: [Universidade Federal de Santa Catarina (LabMat/UFSC), Florianopolis, SC (Brazil). Depto. de Engenharia Mecanica. Laboratorio de Materiais


    Sintered copper-based parts with self-lubricating properties are, nowadays, extensively employed, e.g. in automotive bushes. However, in such components, the liquid lubricant is added after the sintering stage. Recent developments have attempted to substitute the liquid lubricant for a solid one (which is incorporated during the mixing step), aiming operations under extreme conditions where liquids may be ineffective. For powder injection molding (PIM) market, stainless steels are the widest-ranging application group. In this study composites of 17-4 PH stainless steel with 10% vol. of molybdenum disulfide solid lubricant were prepared by PIM. The sintering of the compacts was carried out at various temperatures ranging from 650 to 1300 deg C. The composite structure was analyzed by SEM/EDS, and the phases formed were identified by XRD. Results indicated decomposition of MoS{sub 2} during the sintering cycle, for temperatures above 650 deg C, with formation of others sulfides and supplementary diffusion of molybdenum into the matrix. (author)

  7. Micro and nano sulfide solid lubrication

    Wang, Haidou; Liu, Jiajun


    Sulfide solid lubrication is a vital field of tribology with the potential to save both energy and materials. This book examines the low-temperature sulfuration technology developed in China, as well as two-step methods for preparing sulfide lubrication films.

  8. Lubricants in Pharmaceutical Solid Dosage Forms

    Jinjiang Li


    Full Text Available Lubrication plays a key role in successful manufacturing of pharmaceutical solid dosage forms; lubricants are essential ingredients in robust formulations to achieve this. Although many failures in pharmaceutical manufacturing operations are caused by issues related to lubrication, in general, lubricants do not gain adequate attention in the development of pharmaceutical formulations. In this paper, the fundamental background on lubrication is introduced, in which the relationships between lubrication and friction/adhesion forces are discussed. Then, the application of lubrication in the development of pharmaceutical products and manufacturing processes is discussed with an emphasis on magnesium stearate. In particular, the effect of its hydration state (anhydrate, monohydrate, dihydrate, and trihydrate and its powder characteristics on lubrication efficiency, as well as product and process performance is summarized. In addition, the impact of lubrication on the dynamics of compaction/compression processes and on the mechanical properties of compacts/tablets is presented. Furthermore, the online monitoring of magnesium stearate in a blending process is briefly mentioned. Finally, the chemical compatibility of active pharmaceutical ingredient (API with magnesium stearate and its reactive impurities is reviewed with examples from the literature illustrating the various reaction mechanisms involved.

  9. Friction Regimes in the Lubricants Solid-State Regime

    Schipper, D.J.; Maathuis, O.; Dowson, D.; Taylor, C.M.; Childs, T.H.C.; Dalmaz, G.


    Friction measurements were performed in the lubricant's solid-state regime to study the transition from full-film lubrication, in which the separation is maintained by a solidified lubricant, to mixed lubrication. Special attention is paid to the influence of temperature (inlet viscosity) and roughn

  10. Testing and evaluation of solid lubricants for gas bearings

    Albrecht, P. R.; Fischer, W. H.


    The testing and results of testing solid film lubricants for gas lubricated bearing applications are reported. The tests simulated operational hazards of tilting pad gas bearings. The presence of a low coefficient of friction and the endurance of the solid film lubricant were the criteria for judging superior performance. All solid lubricants tested were applied to a plasma sprayed chrome oxide surface. Molybdenum disulfide and graphite fluoride were the solid lubricants tested; other test parameters included the method of application of the solid lubricant and the surface finish of the plasma sprayed coating. In general, the application of a solid film lubricant was found to significantly improve the coefficient of friction of the rubbing surfaces.

  11. Surface roughness effects with solid lubricants dispersed in mineral oils

    Cusano, C.; Goglia, P. R.; Sliney, H. E.


    The lubricating effectiveness of solid-lubricant dispersions are investigated in both point and line contacts using surfaces with both random and directional roughness characteristics. Friction and wear data obtained at relatively low speeds and at room temperature, indicate that the existence of solid lubricants such as graphite, MoS2, and PTFE in a plain mineral oil generally will not improve the effectiveness of the oil as a lubricant for such surfaces. Under boundary lubrication conditions, the friction force, as a function of time, initially depends upon the directional roughness properties of the contacting surfaces irrespective of whether the base oil or dispersions are used as lubricants.

  12. Graphene oxide film as solid lubricant.

    Liang, Hongyu; Bu, Yongfeng; Zhang, Junyan; Cao, Zhongyue; Liang, Aimin


    As a layered material, graphene oxide (GO) film is a good candidate for improving friction and antiwear performance of silicon-based MEMS devices. Via a green electrophoretic deposition (EPD) approach, GO films with tunable thickness in nanoscale are fabricated onto silicon wafer in a water solution. The morphology, microstructure, and mechanical properties as well as the friction coefficient and wear resistance of the films were investigated. The results indicated that the friction coefficient of silicon wafer was reduced to 1/6 its value, and the wear volume was reduced to 1/24 when using GO film as solid lubricant. These distinguished tribology performances suggest that GO films are expected to be good solid lubricants for silicon-based MEMS/NEMS devices.

  13. Literature Review of Solid Lubrication Mechanisms.


    Other work also suggests limited movement. Connelly and Rabinowicz used exoelectrons to study migration of MoS 2 , graphite, and PTFE on partially...against steel (0.29 to 0.51) as reported by Rabinowicz .( 04) The data for lead are shown in Fig. 10. Although the same trends are seen, there are some... Rabinowicz , E., "Detecting Wear and Migration of Solid- Film Lubricants Using Simultaneous Exoelectron Emission," Trans. ASLE, Vol. 26, No. 2, p. 139

  14. Tribological properties of solid lubricating film/microarc oxidation coating on Al alloys

    LUO Zhuang-zi; ZHANG Zhao-zhu; LIU Wei-min; TIAN Jun


    A process for preparation of solid lubricating films on micro-arc oxidation(MAO) coating was introduced to provide self-lubricating and wear-resistant multilayer coatings for aluminum alloys. The friction and wear behavior of various burnished and bonded solid lubricating films on the as-deposited and polished micro-arc oxidation coatings sliding against steel and ceramic counterparts was evaluated with a Timken tester and a reciprocating friction and wear tester, respectively. The burnished and bonded solid lubricating films on the polished micro-arc oxidation coatings are superior to the as-deposited ones in terms of the wear resistant behavior, because they lead to strengthened interfacial adhesion between the soft lubricating top-film and the hard polished MAO sub-coating, which helps increase the wear resistance of the solid lubricating film on multilayer coating. Thus the multilayer coatings are potential candidates as self-lubricating and wear-resistant coatings for Al alloy parts in engineering applications.

  15. Compatibility of lubricant additives with HFC refrigerants and synthetic lubricants. Final report, Part 1

    Cavestri, R.C. [Imagination Resources, Inc., Dublin, OH (United States)


    Part one of this research provides manufacturers of components of air-conditioning and refrigeration equipment with a useful list of lubricant additives, sources, functional properties and chemical species. The list in part one is comprised of domestic lubricant additive suppliers and the results of a literature search that was specifically targeted for additives reported to be useful in polyolester chemistry.

  16. The Role of Solid Lubricants for Brake Friction Materials

    Werner Österle


    Full Text Available This review article comprises of three parts. Firstly, reports of brake manufacturers on the beneficial impact of solid lubricants for pad formulations are surveyed. Secondly, since tribofilms were identified to play a crucial role in friction stabilization and wear reduction, the knowledge about tribofilm structures formed during automotive braking was reviewed comprehensively. Finally, a model for simulating the sliding behavior of tribofilms is suggested and a review on modelling efforts with different model structures related to real tribofilms will be presented. Although the variety of friction composites involved in commercial brake systems is very broad, striking similarities were observed in respect to tribofilm nanostructures. Thus, a generalization of the tribofilm nanostructure is suggested and prerequisites for smooth sliding performance and minimal wear rates have been identified. A minimum of 13 vol % of soft inclusions embedded in an iron oxide based tribofilm is crucial for obtaining the desired properties. As long as the solid lubricants or their reaction products are softer than magnetite, the main constituent of the tribofilm, the model predicts smooth sliding and minimum wear.

  17. A review of recent advances in solid film lubrication

    Spalvins, T.


    Thin, adherent sputtered MoS2 and ion plated metallic (Au, Ag, Pb) lubricating films are primarily used in precision contacting triboelement surfaces where wear debris formation is critical and high reliability requirements have to be satisfied. Detailed structural and compositional characterization of solid film lubricants is of prime importance. It is this information from the nano-micro-macro level which is needed to interpret and improve the frictional behavior and assure long endurance lives. The purpose of this paper is to summarize in a concise review the solid lubricant film structure and morphology and their effects on the tribological properties of the lubricant systems. The tribological performance of thin lubricating films has significantly advanced through progressive understanding of the film parameters such as adhesion, cohesion, interface formation, nucleation and microstructural growth, critical film thickness and substrate finish, and temperature. Sputtered MoS2 and ion plated Au, Ag, and Pb films are separately discussed and evaluated in terms of the above film parameters to establish the most desirable film structures and thicknesses in order to achieve effective lubrication.

  18. Tribochemistry of Bismuth and Bismuth Salts for Solid Lubrication

    Gonzalez Rodriguez, P.; Nieuwenhuijzen, van den K.J.H.; Lette, W.; Schipper, D.J.; Elshof, ten J.E.


    One of the main trends in the past decades is the reduction of wastage and the replacement of toxic compounds in industrial processes. Some soft metallic particles can be used as nontoxic solid lubricants in high-temperature processes. The behavior of bismuth metal particles, bismuth sulfide (Bi2S3)

  19. The Role of Bulk Additions in Solid Lubricant Compacts


    Solid Lubricants," Labe Ina*- Luis 7 (1967). 5. R. Do Hubbell and B. D. McConnell* "Vear Behavior of Polybonsi-idPsolt Bonded Solld-lilS Lubeioants-S J...0. Grim and Luis J. Matienso, "X-Ray Photoelectron Spectroscopy of Inorganic and Organometallic Ccpounds of Molybdenum," Inors. Cheo., 14, 1014-1018...A. Rincon and L. Arizuendi, "Extreme Pressure Lubricating Properties of Inorganic Oxidus," Wear, 60, 393-399 (1980). 211 86. American Standard for

  20. Thin solid-lubricant films in space

    Roberts, E. W.

    Low-friction films of thickness as low as 1 micron, created through sputter-deposition of low shear strength materials, are required in spacecraft applications requiring low power dissipation, such as cryogenic devices, and low torque noise, such as precision-pointing mechanisms. Due to their thinness, these coatings can be applied to high precision-machined tribological components without compromising their functional accuracy. Attention is here given to the cases of thin solid films for ball bearings, gears, and journal bearings.

  1. Making Self-Lubricating Parts By Powder Metallurgy

    Sliney, Harold E.; Dellacorte, Christopher


    Compositions and parameters of powder-metallurgical fabrication processes determined for new class of low-friction, low-wear, self-lubricating materials. Used in oxidizing or reducing atmospheres in bearings and seals, at temperatures from below 25 degrees C to as high as 900 degrees C. Thick parts made with minimal waste.

  2. Solid Lubricants and Coatings for Extreme Environments: State-of-the-Art Survey

    Miyoshi, Kazuhisa


    An investigation was conducted to survey anticipated requirements for solid lubricants in lunar and Martian environments, as well as the effects of these environments on lubricants and their performance and durability. The success of habitats and vehicles on the Moon and Mars, and ultimately, of the human exploration of and permanent human presence on the Moon and Mars, are critically dependent on the correct and reliable operation of many moving mechanical assemblies and tribological components. The coefficient of friction and lifetime of any lubricant generally vary with the environment, and lubricants have very different characteristics under different conditions. It is essential, therefore, to select the right lubrication technique and lubricant for each mechanical and tribological application. Several environmental factors are hazardous to performance integrity on the Moon and Mars. Potential threats common to both the Moon and Mars are low ambient temperatures, wide daily temperature swings (thermal cycling), solar flux, cosmic radiation, and large quantities of dust. The surface of Mars has the additional challenges of dust storms, winds, and a carbon dioxide atmosphere. Solid lubricants and coatings are needed for lunar and Martian applications, where liquid lubricants are ineffective and undesirable, and these lubricants must perform well in the extreme environments of the Moon, Mars, and space, as well as on Earth, where they will be assembled and tested. No solid lubricants and coatings and their systems currently exist or have been validated that meet these requirements, so new solid lubricants must be designed and validated for these applications.

  3. Surface Modification Of The High Temperature Porous Sliding Bearings With Solid Lubricant Nanoparticles


    A surface modification of stainless steel bearing sleeves is developed to improve the tribology characteristics at high temperature. Solid lubricant nano- and microparticles are applied for this purpose. To create the quasi-hydrodynamic lubrication regimes, the solid lubricant powder layer is made by developed pressure impregnation technique. Porous sliding bearing sleeve prototypes were made by powder metallurgy technique. The purpose of the paper is to define the friction and wear character...

  4. The solid lubricating material experiment device for Shenzhou-7 Spaceship


    A solid lubricating material exposure experiment in space is one of the missions during the seventh manned spaceflight of China,and the key is to develop a device which can be fixed reliably outside of the orbital module and can be fetched conveniently by an astronaut during space walk.The solid lubricating material experiment device needs to be locked reliably in a vibrating and impacting environment during the launch phase,and should meet the requirement that it can be unlocked and fetched reliably by the astronaut wearing an extravehicular spacesuit via simple operations in orbit in an environment of high and low temperature.As for the device we developed,the environmental characteristic of the mission was analyzed,the mechanical analysis and thermal analysis were carried out,and then a mechanism with functions of mechanical locking,structural self-locking and manual unlocking was designed.The device was verified by a sequence of experiments and was fetched by the astronaut during the flight of the Shenzhou-7 Spaceship.

  5. The thermal conductance of solid-lubricated bearings at cryogenic temperatures in vacuum

    Anderson, M. J.


    The thermal conductance of Hertzian contacts is of great importance to cryogenic spacecraft mechanisms such as the Infra-Red Space Observatory (ISO) and the Far Infra-Red Space Telescope (FIRST). At cryogenic temperatures, cooling of mechanism shafts and associated components occurs via conduction through the bearings. When fluid lubricants are cooled below their pour points, they no longer lubricate effectively, and it is necessary to use low shear strength solid lubricants. Currently, only very limited low temperature data exists on the thermal conductance of Hertzian contacts in both unlubricated and lubricated conditions. This paper reports on measurements of thermal conductance made on stationary ball bearings under cryo-vacuum conditions. Quantitative data is provided to support the development of computer models predicting the thermal conductance of Hertzian contacts and solid lubricants at cryogenic temperatures.

  6. Nano K2Ti4O9 Whisker Enhanced Solid Lubrication Coating for Cutting Application

    LIChang-sheng; ZHUCheng-shun; LIUYu; SONGChang-cai; LIUWan-zhang; YANKe-hong; FANZhen; DINGJian-ning; YANGJi-chang


    In order to decrease catting fluid and improve envirorunent, the catting fluid was replaced by solid lubricant. Four kinds of solid lubricants were tested on a high temperature friction tester, from which nano K2Ti4O9 whisker enhanced solid lubrication film was chosen. It was coated on the surface of catters and tested on a CA6140 lathe. At the rate of4OOr/min, the wear of the tool flank with solid lubrication,film is 1/6 of that without the film and it is even lower than that using catting fluid. With the increase of catting speed, the wear of the tool flank with solid lubrication,film is still lower than that without ,film, bat it is higher than that using catting fluid. Surface analyses by AFM , SEM and EDX reveal that the solid lubrication ,film can prevent Fe element of chips from diffusing the cutter surface ; adhesion of the cutter and chips is abated and the wear of the tool flank is obviously decreased.

  7. An Evaluation of Liquid, Solid, and Grease Lubricants for Space Mechanisms Using a Spiral Orbit Tribometer

    Buttery, Michael


    We present the findings of the test program performed by The European Space Tribology Laboratory (ESTL) to evaluate the performance (friction and lifetime) of a number of space lubricants under vacuum using a Spiral Orbit Tribometer (SOT). Focus was given to a comparison of various popular space oils, a comparison study between the old and new MAPLUB grease formulations, and the performance of commonly used solid lubricants under various conditions. Tests demonstrated that the lifetimes of hydrocarbon NYE oils 2001 & 2001A outperformed those of the perfluroropolyalkylether (PFPE) oils Fomblin Z25 & Z60, though these pairs displayed similar behavior. This relationship was also generally seen for greases; with the lifetimes of the multiple alkylated cyclopentane (MAC)-based greases being extended in comparison to the PFPE-based greases. Testing on greases also demonstrated similar performance between the old (-a) and new (-b) formulations when considering PFPE-based MAPLUB greases, and indeed for all tested PFPE-based non-MAPLUB greases, but significantly shorter lifetimes for the new formulations when considering MAC-based MAPLUB greases. MAPLUB MAC greases containing molybdenum disulphide (MoS2) thickener were also found to display reduced lifetimes. For solid lubricants, lead displayed significantly extended lifetimes over MoS2, speculated to be caused by redistribution of lead from the ball onto all contact surfaces during the test. Friction coefficients were seen to be some 2.5x higher for lead than for MoS2 under similar conditions, a result that corresponds well with conventional bearing tests. The work described was performed under contract for the European Space Agency as part of the Tribology Applications Program, with all funding for testing and apparatus provided by European Space Agency (ESA).

  8. Surface Modification Of The High Temperature Porous Sliding Bearings With Solid Lubricant Nanoparticles

    Wiśniewska-Weinert H.


    Full Text Available A surface modification of stainless steel bearing sleeves is developed to improve the tribology characteristics at high temperature. Solid lubricant nano- and microparticles are applied for this purpose. To create the quasi-hydrodynamic lubrication regimes, the solid lubricant powder layer is made by developed pressure impregnation technique. Porous sliding bearing sleeve prototypes were made by powder metallurgy technique. The purpose of the paper is to define the friction and wear characteristics of the sleeves and to determine the influence of sealing of the sliding interface on these characteristics. It is found that application of WS2 sold lubricant nano- and micro-particles and preservation of a particle leakage out of interface allows to achieve at the high temperature the friction coefficients comparable to those at ambient temperature.

  9. Increasing the wear resistance of ultra-high molecular weight polyethylene by adding solid lubricating fillers

    Panin, S. V., E-mail: [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055, Russia and National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Kornienko, L. A.; Poltaranin, M. A.; Ivanova, L. R. [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Suan, T. Nguen [National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)


    In order to compare effectiveness of adding solid lubricating fillers for polymeric composites based on ultra-high molecular weight polyethylene (UHMWPE) with graphite, molybdenum disulfide and polytetrafluoroethylene, their tribotechnical characteristics under dry friction, boundary lubrication and abrasive wearing were investigated. The optimal weight fractions of fillers in terms of improving wear resistance have been determined. The supramolecular structure and topography of wear track surfaces of UHMWPE-based composites with different content of fillers have been studied.

  10. Surface texturing for adaptive Ag/MoS_2 solid lubricant plating


    The objective of this research is to prepare specially designed surface texture on hard steel surface by electrochemical micromachining (EM) and to incorporate electroless plated Ag/MoS2 solid lubricant coating into the dimples of EM textured steel surface to effectively reduce friction and wear of steel-steel contacts. The friction and wear behavior of the Ag/MoS2 solid lubricant coating on EM textured steel surface was evaluated in relation to the size and spacing of the dimples thereon. The microstructur...

  11. Solid Lubrication by Multiwalled Carbon Nanotubes in Air and in Vacuum for Space and Aeronautics Applications

    Miyoshi, Kazuhisa; Street, Kenneth W., Jr.; Andraws, Rodney; Jacques, David; VanderWal, Randy L.; Sayir, Ali


    To evaluate recently developed aligned multiwalled carbon nanotubes (MWNTs) and dispersed MWNTs for solid lubrication applications, unidirectional sliding friction experiments were conducted with 440 C stainless steel balls and hemispherical alumina-yttria stabilized zirconia pins in sliding contact with the MWNTs deposited on quartz disks in air and in vacuum. The results indicate that MWNTs have superior solid lubrication friction properties and endurance lives in air and vacuum under dry conditions. The coefficient of friction of the dispersed MWNTs is close to 0.05 and 0.009 in air and in vacuum, respectively, showing good dry lubricating ability. The wear life of MWNTs exceeds 1 million passes in both air and vacuum showing good durability. In general, the low coefficient of friction can be attributed to the combination of the transferred, agglomerated patches of MWNTs on the counterpart ball or pin surfaces and the presence of tubular MWNTs at interfaces.

  12. Analysis of hazardous organic residues from sodium hydrosulfite industry and utilization as raw materials in a novel solid lubricant production

    Shang, Jiwu [State Key Laboratory of Geological Processes and Mineral Resources, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Zhang, Yihe, E-mail: [State Key Laboratory of Geological Processes and Mineral Resources, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Zhou, Fengshan; Lv, Fengzhu; Han, Feng; Lu, Jinbo; Meng, Xianghai [State Key Laboratory of Geological Processes and Mineral Resources, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Ye, Zhengfang [Department of Environmental Engineering, Key Laboratory of Water and Sediment Sciences of the Ministry of Education, Peking University, Beijing 100871 (China); Xing, Jing [State Key Laboratory of Geological Processes and Mineral Resources, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China)


    Highlights: Black-Right-Pointing-Pointer The hazardous organic residual wastes produced by the sodium hydrosulfite industry are analyzed and the main compounds are found to be thiodiglycol and 2,2 Prime -dithiodiethanol. Black-Right-Pointing-Pointer The lubricity of the organic residues is subsequently studied and the homemade solid lubricant is observed to have good lubricity. Black-Right-Pointing-Pointer The clean process is expected to not only have commercial impact but also help to reduce environmental pollution. - Abstract: The hazardous organic residual wastes produced by the sodium hydrosulfite industry are demonstrated to be convertible into a novel solid lubricant. Identification and isolation of the organic residues are achieved by Fourier transform infrared (FTIR) spectroscopy, gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR). FTIR and GC-MS provide important information about the residues and the two main components obtained by column chromatography are further analyzed by NMR. The main organic residues are found to be thiodiglycol and 2,2 Prime -dithiodiethanol which have potential applications in petroleum drilling because of their S-S and/or C-S functional groups. The lubricity of the organic residues is subsequently studied and the influence of different adsorbents on the lubricity is investigated and discussed. This homemade lubricant is observed to have good lubricity and by increasing the concentration of the commercial solid lubricant M, the lubricity diminishes. The process is expected to not only have commercial impact but also help to reduce environmental pollution.

  13. Long-lasting solid lubrication by CNT-coated patterned surfaces

    Reinert, L.; Lasserre, F.; Gachot, C.; Grützmacher, P.; MacLucas, T.; Souza, N.; Mücklich, F.; Suarez, S.


    The use of lubricants (solid or liquid) is a well-known and suitable approach to reduce friction and wear of moving machine components. Another possibility to influence the tribological behaviour is the formation of well-defined surface topographies such as dimples, bumps or lattice-like pattern geometries by laser surface texturing. However, both methods are limited in their effect: surface textures may be gradually destroyed by plastic deformation and lubricants may be removed from the contact area, therefore no longer properly protecting the contacting surfaces. The present study focuses on the combination of both methods as an integral solution, overcoming individual limitations of each method. Multiwall carbon nanotubes (MWCNT), a known solid lubricant, are deposited onto laser surface textured samples by electrophoretic deposition. The frictional behaviour is recorded by a tribometer and resulting wear tracks are analysed by scanning electron microscopy and Raman spectroscopy in order to reveal the acting tribological mechanisms. The combined approach shows an extended, minimum fivefold longevity of the lubrication and a significantly reduced degradation of the laser textures. Raman spectroscopy proves decelerated MWCNT degradation and oxide formation in the contact. Finally, a lubricant entrapping model based on surface texturing is proposed and demonstrated.

  14. Active tilting-pad journal bearings supporting flexible rotors: Part I – The hybrid lubrication

    Salazar, Jorge Andrés González; Santos, Ilmar


    This is part I of a twofold paper series, of theoretical and experimental nature, presenting the design and implementation of model-based controllers meant for assisting the hybrid and developing the feedback-controlled lubrication regimes in active tilting-pad journal bearings (active TPJBs......). In part I, the flexible rotor-active TPJB modelling is thoroughly covered by establishing the link between the mechanical and hydraulic systems for all regimes. The hybrid lubrication is herein covered in depth; from a control viewpoint, an integral controller to aid such a regime is designed using model......-based standard tools. Results show slight improvement on the system dynamic performance by using the hybrid lubrication instead of the passive one. Further improvements are pursued with the active lubrication in part II....

  15. Effective moduli of particulate solids: Lubrication approximation method

    Qi, F.; Phan-Thien, N.; X. J. Fan

    To efficiently calculate the effective properties of a composite, which consists of rigid spherical inclusions not necessarily of the same sizes in a homogeneous isotropic elastic matrix, a method based on the lubrication forces between neighbouring particles has been developed. The method is used to evaluate the effective Lamé moduli and the Poisson's ratio of the composite, for the particles in random configurations and in cubic lattices. A good agreement with experimental results given by Smith (1975) for particles in random configurations is observed, and also the numerical results on the effective moduli agree well with the results given by Nunan & Keller (1984) for particles in cubic lattices.

  16. Determination of the Tribological Fundamentals of Solid Lubricated Ceramics. Volume 3. Appendices P through II


    be investigated from the approach of preparing solid surfaces of extreme purity and perfection. However such surfaces must be maintained in a very high...system is of interest when the solid lubricant TiN is considered as shown in Figure 4-6.13 The primary phase fields are rutile, cristobalite , mullite...analysis and surface [6]. The preparation of the pin was tribotesting, a specimen can be cleaned by carried out in the same way. the secondary ion

  17. Evaluation of Advanced Solid Lubricant Coatings for Foil Air Bearings Operating at 25 and 500 C

    DellaCorte, Christopher; Fellenstein, James A.; Benoy, Patricia A.


    The tribological properties of one chrome oxide and one chrome carbide based solid lubricant coating were evaluated in a partial-arc foil bearing at 25 and 500 C. Start/stop bearing operation up to 20,000 cycles were run under 10 kPa (1.5 psi) static deadweight load. Bearing friction (torque) was measured during the test. Specimen wear and SEM/EDS surface analyses were conducted after testing to understand and elucidate the tribological characteristics observed. The chrome oxide coating which contains both (Ag) and (BaF2/CaF2) for low and high temperature lubrication, exhibited low friction in sliding against Al2O3 coated foils at 25 and 500 C. The chrome carbide coating, which lacked a low temperature lubricant but contained BaF2/CaF2 as a high temperature lubricant, exhibited high friction at 25 C and low friction at 500 C against both bare and Al2O3 coated superalloy foil surfaces. Post test surface analyses suggest that improved tribological performance is exhibited when a lubricant film from the coating transfers to the foil surface.

  18. Single Common Powertrain Lubricant (SCPL) Development. Part 2


    engine laboratory building. Back-pressure was controlled through a butterfly valve located in the exhaust stack prior to the buildings common exhaust ventilation system integrated into the engine laboratory building. Back-pressure was controlled via a butterfly valve located in the...This test evaluates a lubricants ability to protect roller follower valve train components from wear in high load at low to moderate engine speed

  19. Atomistic study of ternary oxides as high-temperature solid lubricants

    Gao, Hongyu

    Friction and wear are important tribological phenomena tightly associated with the performance of tribological components/systems such as bearings and cutting machines. In the process of contact and sliding, friction and wear lead to energy loss, and high friction and wear typically result in shortened service lifetime. To reduce friction and wear, solid lubricants are generally used under conditions where traditional liquid lubricants cannot be applied. However, it is challenging to maintain the functionality of those materials when the working environment becomes severe. For instance, at elevated temperatures (i.e., above 400 °C), most traditional solid lubricants, such as MoS2 and graphite, will easily oxidize or lose lubricity due to irreversible chemical changes. For such conditions, it is necessary to identify materials that can remain thermally stable as well as lubricious over a wide range of temperatures. Among the currently available high-temperature solid lubricants, Ag-based ternary metal oxides have recently drawn attention due to their low friction and ability to resist oxidation. A recent experimental study showed that the Ag-Ta-O ternary exhibited an extremely low coefficient of friction (0.06) at 750 °C. To fully uncover the lubricious nature of this material as a high-temperature solid lubricant, a series of tribological investigations were carried out based on one promising candidate - silver tantalate (AgTaO3). The study was then extended to alternative materials, Cu-Ta-O ternaries, to accommodate a variety of application requirements. We aimed to understand, at an atomic level, the effects of physical and chemical properties on the thermal, mechanical and tribological behavior of these materials at high temperatures. Furthermore, we investigated potassium chloride films on a clean iron surface as a representative boundary lubricating system in a nonextreme environment. This investigation complemented the study of Ag/Cu-Ta-O and enhanced the

  20. Composite Coatings with Ceramic Matrix Including Nanomaterials as Solid Lubricants for Oil-Less Automotive Applications

    Posmyk A.


    Full Text Available The paper presents the theoretical basis of manufacturing and chosen applications of composite coatings with ceramic matrix containing nanomaterials as a solid lubricant (AHC+NL. From a theoretical point of view, in order to reduce the friction coefficient of sliding contacts, two materials are required, i.e. one with a high hardness and the other with low shear strength. In case of composite coatings AHC+NL the matrix is a very hard and wear resistant anodic oxide coating (AHC whereas the solid lubricant used is the nanomaterial (NL featuring a low shear strength such as glassy carbon nanotubes (GC. Friction coefficient of cast iron GJL-350 sliding against the coating itself is much higher (0.18-0.22 than when it slides against a composite coating (0.08-0.14. It is possible to reduce the friction due to the presence of carbon nanotubes, or metal nanowires.

  1. Post Irradiation Evaluation of Thermal Control Coatings and Solid Lubricants to Support Fission Surface Power Systems

    Bowman, Cheryl L.; Jaworske, Donald A.; Stanford, Malcolm K.; Persinger, Justin A.; Khorsandi, Behrooz; Blue, Thomas E.


    The development of a nuclear power system for space missions, such as the Jupiter Icy Moons Orbiter or a lunar outpost, requires substantially more compact reactor design than conventional terrestrial systems. In order to minimize shielding requirements and hence system weight, the radiation tolerance of component materials within the power conversion and heat rejection systems must be defined. Two classes of coatings, thermal control paints and solid lubricants, were identified as material systems for which limited radiation hardness information was available. Screening studies were designed to explore candidate coatings under a predominately fast neutron spectrum. The Ohio State Research Reactor Facility staff performed irradiation in a well characterized, mixed energy spectrum and performed post irradiation analysis of representative coatings for thermal control and solid lubricant applications. Thermal control paints were evaluated for 1 MeV equivalent fluences from 1013 to 1015 n/cm2. No optical degradation was noted although some adhesive degradation was found at higher fluence levels. Solid lubricant coatings were evaluated for 1 MeV equivalent fluences from 1015 to 1016 n/cm2 with coating adhesion and flexibility used for post irradiation evaluation screening. The exposures studied did not lead to obvious property degradation indicating the coatings would have survived the radiation environment for the previously proposed Jupiter mission. The results are also applicable to space power development programs such as fission surface power for future lunar and Mars missions.

  2. Post Irradiation Evaluation of Thermal Control Coatings and Solid Lubricants to Support Fission Surface Power Systems

    Bowman, Cheryl L.; Jaworske, Donald A.; Stanford, Malcolm K.; Persinger, Justin A.; Khorsandi, Behrooz; Blue, Thomas E.


    The development of a nuclear power system for space missions, such as the Jupiter Icy Moons Orbiter or a lunar outpost, requires substantially more compact reactor design than conventional terrestrial systems. In order to minimize shielding requirements and hence system weight, the radiation tolerance of component materials within the power conversion and heat rejection systems must be defined. Two classes of coatings, thermal control paints and solid lubricants, were identified as material systems for which limited radiation hardness information was available. Screening studies were designed to explore candidate coatings under a predominately fast neutron spectrum. The Ohio State Research Reactor Facility staff performed irradiation in a well characterized, mixed energy spectrum and performed post irradiation analysis of representative coatings for thermal control and solid lubricant applications. Thermal control paints were evaluated for 1 MeV equivalent fluences from 10(exp 13) to 10(exp 15) n per square centimeters. No optical degradation was noted although some adhesive degradation was found at higher fluence levels. Solid lubricant coatings were evaluated for 1 MeV equivalent fluences from 10(exp 15) to 10(exp 16) n per square centimeters with coating adhesion and flexibility used for post irradiation evaluation screening. The exposures studied did not lead to obvious property degradation indicating the coatings would have survived the radiation environment for the previously proposed Jupiter mission. The results are also applicable to space power development programs such as fission surface power for future lunar and Mars missions.

  3. Effects of nano-LaF{sub 3} on the friction and wear behaviors of PTFE-based bonded solid lubricating coatings under different lubrication conditions

    Jia, Yulong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wan, Hongqi, E-mail: [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Chen, Lei, E-mail: [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhou, Huidi [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Chen, Jianmin, E-mail: [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)


    Highlights: • Nano-LaF{sub 3} was used to modify tribological behavior of PTFE bonded solid lubricating coating. • The tribological properties of lubricating coatings were investigated under different lubrication conditions. • The modified PTFE bonded coating exhibited superior tribological performance both under two kinds of lubrication conditions. - Abstract: Influence of nanometer lanthanum fluoride (nano-LaF{sub 3}) on the tribological behaviors of polytetrafluoroethylene (PTFE) bonded solid lubricating coatings were investigated using a ring-on-block friction-wear tester under dry friction and RP-3 jet fuel lubrication conditions. The worn surfaces and transfer films formed on the counterpart steel rings were observed by scanning electron microscope (SEM) and optical microscope (OM), respectively. The microstructures of the nano-LaF{sub 3} modified coatings and the distribution states of nano-LaF{sub 3} were studied by field-emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM), respectively. The results show that incorporation of nano-LaF{sub 3} improves the microhardness and the friction-reduced and anti-wear abilities of PTFE bonded solid lubricating coatings. The wear life of the modified coating is about 6 times longer than that of the coating without nano-LaF{sub 3} filler at a relatively low applied load (200 N) and rotary speed (1000 rev/min) under dry friction condition. The friction coefficient and wear life of the modified coating decrease with increase of applied load under dry friction, but the friction coefficient has hardly any variation and wear life decreases under RP-3 jet fuel lubrication condition. In addition, the friction coefficient of the modified coating reduces with the rotary speed increasing under dry sliding but has little change under RP-3 lubrication, the wear life increases firstly and then decreases. The results indicated that the wear failure mechanism is dominated by applied load

  4. Preparation QTi3.5-3.5 Graphite Lubricant Material with Semi-solid Casting Technology

    Peng ZHANG; Yunhui DU; Daben ZENG; Jianzhong CUI; Limin BA


    For the first time, the distribution of graphite particles in QTi3.5-3.5 graphite ingot was studied by using semi-solid casting technology. The results show that: the relationship between solid fraction and stirring temperature of QTi3.5-3.5 graphite slurry is y=759.4-0.711x (where y is solid fraction, x is stirring temperature). With the increasing of solid fraction of QTi3.5-3.5 graphite slurry, the agglomeration of graphite particles in ingot reduces gradually. The condition to prepare QTi3.5-3.5 graphite lubricant material with even distribution of graphite particles is that the solid fraction of QTi3.5-3.5 graphite slurry is larger than 40%.

  5. How tests of lubricating and transformer oils became part of power plant chemistry in Denmark

    Moeller, H. [I/S Nordjyllandsvaerket, Vodskov (Denmark)


    Lubricating, hydraulic and transformer oils based on refined crude oil are used in nearly all power station components, such as gear, turbines, hydraulic stations, feed pumps and transformers. The function of these components totally depends on the condition of the oils and their properties. Seen from this point one may wonder why examination and evaluation of oils did not become part of the power station chemistry within the ELSAM utility area until during the middle of the eighties. We started to examine the properties of lubricating oils at the time when several steam turbines experienced serious problems with formation of deposits in their hydraulic control circuits. This work was intensified in connection with the significant number of CHPs and wind turbines erected within the Danish electricity sector during the past 10 years or so. The majority of the CHPs are natural gas fired turbines or motors, equipment which severely stresses the lubricating oil. In collaboration with KEMA, the Netherlands, we have carried through with a large examination of lubricating oils in gas turbines and we have found suitable oil types. The objectives of our work with lubricating and transformer oils have been to link together the laboratory measurements with operational experience. Only by doing this is it possible to utilize the laboratory measurements in a correct way. It must be remembered that the main part of all oil specifications concerns the properties of new oils. Only very little is published about the requirements concerning used oils. (EG)

  6. The effect of surface roughness on the adhesion of solid surfaces for systems with and without liquid lubricant

    Samoilov, V. N.; Sivebæk, Ion Marius; Persson, B. N. J.


    ) of octane. For the flat substrate without lubricant the maximum adhesion was found to be approximately three times larger than for the system with the corrugated substrate. As a function of the octane coverage (for the corrugated substrate) the pull-off force first increases as the coverage increases from 0......We present molecular dynamics results for the interaction between two solid elastic walls during pull-off for systems with and without octane (C8H18) lubricant. We used two types of substrate-flat and corrugated-and varied the lubricant coverage from similar to1/8 to similar to4 ML (monolayers...... around the substrate nanoasperities, thus increasing the adhesion between two surfaces. For greater lubricant coverages a single capillary bridge is formed. The adhesion force saturates for lubricant coverages greater than 3 ML. For the flat substrate, during pull-off we observe discontinuous, thermally...

  7. Commercialization of NASA PS304 Solid Lubricant Coating Enhanced by Fundamental Powder Flow Research

    Stanford, Malcolm K.


    The NASA Glenn Research Center has developed a patented high-temperature solid lubricant coating, designated PS304, for reducing friction and wear in bearing systems. The material used to produce the coating is initially a blend of metallic and ceramic powders that are deposited on the bearing surface by the plasma spray process. PS304 was developed to lubricate foil air bearings in Oil-Free turbomachinery, where the moving surfaces are coated with a hydrodynamic air film except at the beginning and end of an operation cycle when the air film is not present. The coating has been successful in several applications including turbochargers, land-based turbines, and industrial drying furnace conveyor components, with current development activities directed at implementation in Oil-Free aeropropulsion engines.

  8. Dynamic friction and wear of a solid film lubricant during radiation exposure in a nuclear reactor

    Jacobson, T. P.


    The effect of nuclear reactor radiation on the performance of a solid film lubricant was studied. The film consisted of molybdenum disulfide and graphite in a sodium silicate binder. Radiation levels of fast neutrons (E or = 1 MeV) were fluxed up to 3.5 times 10 to the 12th power n/sq cm-sec (intensity) and fluences up to 2 times 10 to the 18th power n/sq cm (total exposure). Coating wear lives were much shorter and friction coefficients higher in a high flux region of the reactor than in a low flux region. The amount of total exposure did not affect lubrication behavior as severely as the radiation intensity during sliding.

  9. Relation of Certain Quantum Chemical Parameters to Lubrication Behavior of Solid Oxides

    Yuansheng Jin


    Full Text Available Abstract: It is well-documented that certain oxides (such as Re2O7, B2O3, MoO3, V2O5, etc. can provide friction coefficients of 0.1-0.3 to sliding surfaces at elevated temperatures and thus they are often referred to as lubricious oxides in the tribology literature. In a recently proposed crystal chemical model, Erdemir was able to establish a close correlation between the reported friction coefficients of such oxides and their ionic potentials [1]. In the present paper, we expand on this original concept and explore the relevance of two other quantum chemical parameters, electronegativity and chemical hardness, to the lubricity of solid oxides. These parameters have already been used by scientists to explain the nature of tribochemical interactions between various oil additives and sliding surfaces. It is conceivable that electronegativity and chemical hardness may also be strongly related to the extent of adhesive interactions and shear rheology of solid oxides and hence to their lubricity. The new results have confirmed that electronegativity, like ionic potential, is indeed a valid quantum chemistry parameter that can be used in predicting the lubrication behavior of solid oxides. Generally, the higher the electronegativity of the solid oxides is, the lower the friction coefficients will be. However, chemical hardness did not yield a similar trend. In light of these new findings, we propose some guidelines for the formulation of novel oxide or alloy systems that can lead to the formation of lubricious oxides at elevated temperatures. The findings of this study may pave the way for designer-based tribosystems in general and smart tribochemical systems in particular in future tribological applications such as dry machining.

  10. Squeezing molecular thin alkane lubrication films between curved solid surfaces with long-range elasticity: Layering transitions and wear

    Sivebæk, Ion Marius; Samoilov, V. N.; Persson, B. N. J.


    The properties of alkane lubricants confined between two approaching solids are investigated by a model that accounts for the curvature and the elastic properties of the solid surfaces. We consider linear alkane molecules of different chain lengths, C3H8, C4H10, C8H18, C9H20, C10H22, C12H26 and C14......H30 confined between smooth gold surfaces. In most cases we observe well defined molecular layers develop in the lubricant film when the width of the film is of the order of a few atomic diameters. An external squeezing-pressure induces discontinuous, thermally activated changes in the number n...... of lubricant layers. We find that with increasing alkane chain length, the transition from n to n-1 layers occurs at higher pressure, as expected based on the increasing wettability ~or spreading pressure with increasing chain length. Thus, the longer alkanes are better boundary lubricants than the shorter...

  11. The Effect of Composition on the Surface Finish of PS400: A New High Temperature Solid Lubricant Coating

    DellaCorte, Christopher; Stanford, malcolm K.; Thomas, Fransua; Edmonds, Brian J.


    A new composite, multi-constituent, solid lubricant coating, NASA PS400, developed for high temperature tribological applications, exhibits a smoother surface finish after grinding and polishing than its predecessors PS200 and PS300. In this paper, the baseline composition of PS400 is modified to investigate each individual constituent s role on the achievable surface finish through a series of coating deposition, grinding, and polishing experiments. Furthermore, to explore the limits of compositional tailoring for improved tribological performance, several PS400 coatings were doped with additional solid lubricants (graphite, MoS2 and BN) and tribologically tested. The test results clearly showed that, compared to PS300 coatings, PS400 achieves a smoother surface finish via a reduced lubricant content. Coatings prepared with higher than the baseline level (10 wt%) of lubricants exhibited higher final surface roughness than the earlier generation PS300 coatings. Reducing or eliminating the one or both lubricants (fluorides or silver) did not further improve the surface finish suggesting that the current composition of PS400 is near optimal with respect to surface finish. Lastly, attempts to improve the poor initial room temperature tribological behavior of PS400 via the addition of traditional solid lubricants were unsuccessful. Based upon this work and earlier results it is expected that future research will concentrate on developing methods to produce a lubricious glaze on the rubbing surface during break in to ensure that low friction and wear are rapidly achieved.

  12. (Ag,Cu)-Ta-O ternaries as high-temperature solid-lubricant coatings.

    Gao, Hongyu; Otero-de-la-Roza, Alberto; Gu, Jingjing; Stone, D'Arcy; Aouadi, Samir M; Johnson, Erin R; Martini, Ashlie


    Ternary oxides have gained increasing attention due to their potential use as solid lubricants at elevated temperatures. In this work, the tribological properties of three ternary oxides-AgTaO3, CuTaO3, and CuTa2O6-were studied using a combination of density-functional theory (DFT), molecular dynamics (MD) simulations with newly developed empirical potential parameters, and experimental measurements (AgTaO3 and CuTa2O6 only). Our results show that the MD-predicted friction force follows the trend AgTaO3 behavior of these materials.

  13. Effects of nano-LaF3 on the friction and wear behaviors of PTFE-based bonded solid lubricating coatings under different lubrication conditions

    Jia, Yulong; Wan, Hongqi; Chen, Lei; Zhou, Huidi; Chen, Jianmin


    Influence of nanometer lanthanum fluoride (nano-LaF3) on the tribological behaviors of polytetrafluoroethylene (PTFE) bonded solid lubricating coatings were investigated using a ring-on-block friction-wear tester under dry friction and RP-3 jet fuel lubrication conditions. The worn surfaces and transfer films formed on the counterpart steel rings were observed by scanning electron microscope (SEM) and optical microscope (OM), respectively. The microstructures of the nano-LaF3 modified coatings and the distribution states of nano-LaF3 were studied by field-emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM), respectively. The results show that incorporation of nano-LaF3 improves the microhardness and the friction-reduced and anti-wear abilities of PTFE bonded solid lubricating coatings. The wear life of the modified coating is about 6 times longer than that of the coating without nano-LaF3 filler at a relatively low applied load (200 N) and rotary speed (1000 rev/min) under dry friction condition. The friction coefficient and wear life of the modified coating decrease with increase of applied load under dry friction, but the friction coefficient has hardly any variation and wear life decreases under RP-3 jet fuel lubrication condition. In addition, the friction coefficient of the modified coating reduces with the rotary speed increasing under dry sliding but has little change under RP-3 lubrication, the wear life increases firstly and then decreases. The results indicated that the wear failure mechanism is dominated by applied load, which plays an important role in guidance of application of nano-LaF3 modified PTFE bonded coating under different working environment.

  14. Calculation of flash temperature for hybrid ceramic ball bearing lubricated with solid

    李秀娟; 王黎钦; 古乐; 齐毓霖


    The scuffing behavior of hybrid ceramic bearing lubricated with solid is greatly affected by the contact flash temperature. Formulas are dedused using Lee' s asperity flash temperature method, to calculate the flash temperature of ball bearing lubricated with solid. The maximum flash temperature is calculated for hybrid ceramic ball bearings. The results show that under given conditions, the flash temperature of inner race is higher than that of outer race, the flash temperature of the hybrid ceramic bearing is sensitive to the load, rotational speed and race curvature. The flash temperature of inner race at 20 000 r/min is 66.9% more than that that at 11 000 r/min, and with the load changing from 1.1 kN to 2 kN, the flash temperature inner race goes up to 165.7%. Very common for high speed ball bearings, when curvature coefficients of both inner and outer race change from 0. 515 to 0.56, the inner race flash temperature decreases from 421. 446℃ to 56.2℃.

  15. Tribological and Mechanical Behaviors of Polyamide 6/Glass Fiber Composite Filled with Various Solid Lubricants

    Duxin Li


    Full Text Available The effects of polytetrafluoroethylene (PTFE, graphite, ultrahigh molecular weight polyethylene (UHMWPE, and their compounds on mechanical and tribological properties of glass-fiber-reinforced polyamide 6 (PA6/GF were studied. The polymeric materials were blended using twin-screw extruder and subsequently injection molded for test samples. Mechanical properties were investigated in terms of hardness, tensile strength, and impact strength. Friction and wear experiments were run under ambient conditions at a rotating speed of 200 rpm and load of 100 N. The morphologies of the worn surfaces were also observed with scanning electron microscope. The results showed that graphite could increase the tensile strength of PA6/GF-15 composite, but the material became soft. Graphite/UHMWPE complex solid lubricants were effective in increasing the already high impact strength of PA6/GF-15 composite. 5% PTFE gave the maximum reduction in the coefficient of friction. However, PTFE/UHMWPE complex solid lubricants were the best choice for improving both friction and wear behaviors due to the lower friction coefficient and mass wear rate. Moreover, the worn surface of PA6 composites revealed that adhesive wear, abrasive wear, and fatigue wear occurred in this study.

  16. Tribological and mechanical behaviors of polyamide 6/glass fiber composite filled with various solid lubricants.

    Li, Duxin; Xie, Ying; Li, Wenjuan; You, Yilan; Deng, Xin


    The effects of polytetrafluoroethylene (PTFE), graphite, ultrahigh molecular weight polyethylene (UHMWPE), and their compounds on mechanical and tribological properties of glass-fiber-reinforced polyamide 6 (PA6/GF) were studied. The polymeric materials were blended using twin-screw extruder and subsequently injection molded for test samples. Mechanical properties were investigated in terms of hardness, tensile strength, and impact strength. Friction and wear experiments were run under ambient conditions at a rotating speed of 200 rpm and load of 100 N. The morphologies of the worn surfaces were also observed with scanning electron microscope. The results showed that graphite could increase the tensile strength of PA6/GF-15 composite, but the material became soft. Graphite/UHMWPE complex solid lubricants were effective in increasing the already high impact strength of PA6/GF-15 composite. 5% PTFE gave the maximum reduction in the coefficient of friction. However, PTFE/UHMWPE complex solid lubricants were the best choice for improving both friction and wear behaviors due to the lower friction coefficient and mass wear rate. Moreover, the worn surface of PA6 composites revealed that adhesive wear, abrasive wear, and fatigue wear occurred in this study.

  17. Endodontic 'solutions' part 1: a literature review on the use of endodontic lubricants, irrigants and medicaments.

    Good, Melissa; El, Karim Ikhlas A; Hussey, David L


    Endodontic lubricants, irrigants and medicaments help prepare and disinfect root canal systems (RCS) but primary and secondary cases involve different microbes and therefore it is unlikely that one protocol will be effective for both case types. Each individual 'solution' or sequence of'solutions' could play a significant role in each case type, but there are no detailed published guidelines in existence. To help inform clinical practice it was decided to undertake a literature review followed by a UK and Republic of Ireland wide audit on current endodontic'solution' usage within dental schools. The literature review was undertaken under the following headings: pre-op oral rinse; file lubricants; root canal irrigants and intracanal medicaments and provides an evidence base for protocol development for both primary and retreatment cases.The audit project and the protocols developed from the findings of both the literature review and audit will be presented in Part 2.

  18. Improvement of Drill Performance in Metal Cutting Using MoST Solid Lubricant Coatings

    N.R.Thomas; D.G.Teer; S.Yang; S,Hickman


    Coated tools are widely used in today's metal cutting industries and have significantly improved machining productivity through reducing operation costs and "time. This paper presents the results of a systematic study of the performance of HSS drills coated with CrTiAlN and drills with a top solid lubricant coating of MoSTTM. The tests were performed on a Haas vertical machining centre under wet and dry cutting conditions to machine through holes in medium carbon steel workpieces. The feed force and torque were recorded throughout some of the tests using a force dynamometer, while the tool wear was monitored and measured. It was found that MoSTTM coatings even under accelerated conditionsimprove the tool life significantly based on their unique properties and very low friction.

  19. Improvement of Drill Performance in Metal Cutting Using MoST Solid Lubricant Coatings

    N.R. Thomas; D.G. Teer; S. Yang; S. Hickman


    Coated tools are widely used in today's metal cutting industries and have significantly improved machining productivity through reducing operation costs and time. This paper presents the results of a systematic study of the performance of HSS drills coated with CrTiAlN and drills with a top solid lubricant coating of MoSTTM. The tests were performed on a Haas vertical machining centre under wet and dry cutting conditions to machine through holes in medium carbon steel workpieces. The feed force and torque were recorded throughout some of the tests using a force dynamometer,while the tool wear was monitored and measured. It was found that MoSTTM coatings even under accelerated conditions improve the tool life significantly based on their unique properties and very low friction.

  20. A Solid Film Lubricant Composition for Use at High Sliding Velocities in Liquid Nitrogen

    Wisander, D. W.; Johnson, R. L.


    Solid-lubricant-containing compositions can be of value as films and solid bodies for bearing and seal surfaces in low-temperature liquefied gases. An experimental composition including polytetrafluoroethylene (PTFE), an epoxy resin, and lithium-alumina-silicate was studied in friction, wear, and endurance experiments in liquid nitrogen (-320 F). This composition was formulated to approximate the thermal expansion of metals used in cryogenic systems. Hemisphere (3/6-in. radius) rider specimens were used and in most experiments the load was 1000 g. Films (0.005-in. thick) on disk specimens gave good endurance life, low rider wear, and desirable friction (f = 0.02 to 0.07). They functioned at a higher sliding velocity (no failure at 16, 000 ft/min) with copper rider specimens than with stainless steel riders (failure at 9000 ft/min). Solid rider material of the experimental composition had good friction and wear properties at sliding velocities above 4000 ft/min. It is important to use the experimental composition with mating materials having good thermal conductivity.

  1. Elasto-hydrodynamic lubrication

    Dowson, D; Hopkins, D W


    Elasto-Hydrodynamic Lubrication deals with the mechanism of elasto-hydrodynamic lubrication, that is, the lubrication regime in operation over the small areas where machine components are in nominal point or line contact. The lubrication of rigid contacts is discussed, along with the effects of high pressure on the lubricant and bounding solids. The governing equations for the solution of elasto-hydrodynamic problems are presented.Comprised of 13 chapters, this volume begins with an overview of elasto-hydrodynamic lubrication and representation of contacts by cylinders, followed by a discussio

  2. Active tilting-pad journal bearings supporting flexible rotors: Part II–The model-based feedback-controlled lubrication

    Salazar, Jorge Andrés González; Santos, Ilmar


    This is part II of a twofold paper series dealing with the design and implementation of model-based controllers meant for assisting the hybrid and developing the feedback-controlled lubrication regimes in active tilting pad journal bearings (active TPJBs). In both papers theoretical and experimen......This is part II of a twofold paper series dealing with the design and implementation of model-based controllers meant for assisting the hybrid and developing the feedback-controlled lubrication regimes in active tilting pad journal bearings (active TPJBs). In both papers theoretical...... and experimental analyses are presented with focus on the reduction of rotor lateral vibration. This part is devoted to synthesising model-based LQG optimal controllers (LQR regulator + Kalman Filter) for the feedback-controlled lubrication and is based upon the mathematical model of the rotor-bearing system...... derived in part I. Results show further suppression of resonant vibrations when using the feedback-controlled or active lubrication, overweighting the reduction already achieved with hybrid lubrication, thus improving the whole machine dynamic performance....

  3. Dynamic spreading of nanofluids on solids part II: modeling.

    Liu, Kuan-Liang; Kondiparty, Kirtiprakash; Nikolov, Alex D; Wasan, Darsh


    Recent studies on the spreading phenomena of liquid dispersions of nanoparticles (nanofluids) have revealed that the self-layering and two-dimensional structuring of nanoparticles in the three-phase contact region exert structural disjoining pressure, which drives the spreading of nanofluids by forming a continuous wedge film between the liquid (e.g., oil) and solid surface. Motivated by the practical applications of the phenomenon and experimental results reported in Part I of this two-part series, we thoroughly investigated the spreading dynamics of nanofluids against an oil drop on a solid surface. With the Laplace equation as a starting point, the spreading process is modeled by Navier-Stokes equations through the lubrication approach, which considers the structural disjoining pressure, gravity, and van der Waals force. The temporal interface profile and advancing inner contact line velocity of nanofluidic films are analyzed through varying the effective nanoparticle concentration, the outer contact angle, the effective nanoparticle size, and capillary pressure. It is found that a fast and spontaneous advance of the inner contact line movement can be obtained by increasing the nanoparticle concentration, decreasing the nanoparticle size, and/or decreasing the interfacial tension. Once the nanofluidic film is formed, the advancing inner contact line movement reaches a constant velocity, which is independent of the outer contact angle if the interfacial tension is held constant.

  4. Three-phase gas-liquid-solid foaming bubble reactors and self-lubricated transport of bitumen froth

    Mata, Clara E.

    Two distinct topics in multi-phase flow of interest of the oil industry are considered in this thesis. Studies of three-phase gas-liquid-solid foaming bubble reactors and self-lubricated transport of bitumen froth are reported. Applications of foams and foaming are found in many industrial processes such as flotation of minerals, enhanced oil recovery, drilling in oil reservoirs, and refining processes. However the physics of foaming and defoaming are not fully understood. Foams trap gas and are not desirable in some processes such as oil refining. Previously, it has been found that foaming may be strongly suppressed in a cold slit bubble reactor by fluidizing hydrophilic particles in the bubbly mixture below the foam. In this work, we fluidized hydrophobic and hydrophilic versions of two different sands in a cold slit foaming bubble reactor. We found that the hydrophobic sands suppress the foam substantially better than their hydrophilic counterparts. To study the capacity of foams to carry particles, we built a new slit foaming bubble reactor, which can be continuously fed with solid particles. Global gas, liquid, and solid holdups were measured for given gas and liquid velocities and solid flow rates. This research provides the fundamental ground work for the identification of flow types in a slit three-phase foaming bubble reactor with continuous injection of particles. Bitumen froth is produced from the oil sands of Athabasca, Canada. When transported in a pipeline, water present in the froth is released in regions of high shear (at the pipe wall). This results in a lubricating layer of water that allows bitumen froth pumping at greatly reduced pressures and hence the potential for savings in pumping energy consumption. Experimental results establishing the features of this self lubrication phenomenon are presented. The pressure gradient of lubricated flows closely follow the empirical law of Blasius for turbulent pipe flow with a constant of proportionality

  5. Friction and Wear Characteristics of a Modified Composite Solid Lubricant Plasma Spray Coating

    Stanford, M. K.; DellaCorte, C.


    LCR304 is a solid lubricant coating composed of Ni-10Cr, Cr2O3, BaF2-CaF2 and Ag and developed for dimensional stability in high temperature air. This coating is a modification of PS304, which differs in that the Ni-Cr constituent contains 20wt% Cr. The tribological characteristics of LCR304 were evaluated by pin-on-disk and foil air bearing rig testing from 25 to 650 C and compared to previous test results with PS304. For both tests, the friction coefficient decreased as temperature increased from 25 to 650 C. Wear generally decreased with increasing temperature for all pin-on-disk tests. LCR304 coated components produced the least wear of Inconel X-750 counterface materials at 427 and 650 C. These results indicate that the LCR304 coating has potential as a replacement for PS304 in, for example, low cycle (minimum wear) applications where dimensional stability is imperative.

  6. Lubrication fundamentals

    Pirro, DM


    This work discusses product basics, machine elements that require lubrication, methods of application, lubricant storage and handling, and lubricant conservation. This edition emphasizes the need for lubrication and careful lubricant selection.

  7. Grease lubrication in rolling bearings

    Lugt, Piet M


    The definitive book on the science of grease lubrication for roller and needle bearings in industrial and vehicle engineering. Grease Lubrication in Rolling Bearings provides an overview of the existing knowledge on the various aspects of grease lubrication (including lubrication systems) and the state of the art models that exist today. The book reviews the physical and chemical aspects of grease lubrication, primarily directed towards lubrication of rolling bearings. The first part of the book covers grease composition, properties and rheology, including thermal

  8. Study of solid lubrication with MoS2 coating in the presence of additives using reciprocating ball-on-flat scratch tester

    A Shankara; Pradeep L Menezes; K R Y Simha; Satish V Kailas


    Molybdenum disulphide (MoS2) based solid lubricant mixtures containing zirconia and graphite were prepared in the laboratory and coated on steel specimens. The experiments were done using reciprocating scratch test for various numbers of cycles. The results showed that the addition of zirconia and graphite into the MoS2 lubricant has improved its properties in terms of both friction and wear. In addition, it was observed that the presence of moisture affects the life of the lubricating film. It was shown that at high temperature the moisture evaporation enhanced the coating performance of the film.

  9. Glass microsphere lubrication

    Geiger, Michelle; Goode, Henry; Ohanlon, Sean; Pieloch, Stuart; Sorrells, Cindy; Willette, Chris


    The harsh lunar environment eliminated the consideration of most lubricants used on earth. Considering that the majority of the surface of the moon consists of sand, the elements that make up this mixture were analyzed. According to previous space missions, a large portion of the moon's surface is made up of fine grained crystalline rock, about 0.02 to 0.05 mm in size. These fine grained particles can be divided into four groups: lunar rock fragments, glasses, agglutinates (rock particles, crystals, or glasses), and fragments of meteorite material (rare). Analysis of the soil obtained from the missions has given chemical compositions of its materials. It is about 53 to 63 percent oxygen, 16 to 22 percent silicon, 10 to 16 percent sulfur, 5 to 9 percent aluminum, and has lesser amounts of magnesium, carbon, and sodium. To be self-supporting, the lubricant must utilize one or more of the above elements. Considering that the element must be easy to extract and readily manipulated, silicon or glass was the most logical choice. Being a ceramic, glass has a high strength and excellent resistance to temperature. The glass would also not contaminate the environment as it comes directly from it. If sand entered a bearing lubricated with grease, the lubricant would eventually fail and the shaft would bind, causing damage to the system. In a bearing lubricated with a solid glass lubricant, sand would be ground up and have little effect on the system. The next issue was what shape to form the glass in. Solid glass spheres was the only logical choice. The strength of the glass and its endurance would be optimal in this form. To behave as an effective lubricant, the diameter of the spheres would have to be very small, on the order of hundreds of microns or less. This would allow smaller clearances between the bearing and the shaft, and less material would be needed. The production of glass microspheres was divided into two parts, production and sorting. Production includes the

  10. Temperature effect of friction and wear characteristics for solid lubricating graphite

    Kim, Yeonwook; Kim, Jaehoon


    Graphite is one of the effective lubricant additives due to its excellent high-temperature endurance and self-lubricating properties. In this study, wear behavior of graphite used as sealing materials to cut off hot gas is evaluated at room and elevated temperature. Wear occurs on graphite seal due to the friction of driving shaft and graphite. Thus, a reciprocating wear test to evaluate the wear generated for the graphite by means of the relative motion between a shaft material and a graphite seal was carried out. The friction coefficient and specific wear rate for the changes of applied load and sliding speed were compared under different temperature conditions considering the actual operating environment. Through SEM observation of the worn surface, the lubricating film was observed and compared with test conditions.

  11. Improvement of wear-resistance of solid lubricants by ionic impact


    of said lubricating material is improved considerably due to changes in the crystalline structure of the surface layer, and further the adherence to the component to be lubricated can be improved. The effect according to the invention, which can be both a reduced friction coefficient and a longer sliding......-life can be verified in an experiment with a ball with a certain load oscillating on the surface layer to be tested measuring the time dependence of the friction coefficient.; The ion-induced changes in the surface crystallinity can be recognized by a reduced reflection of X-rays from the sliding...

  12. Lubricating Grease

    Gow, G.

    Grease lubrication is a complex mixture of science and engineering, requires an interdisciplinary approach, and is applied to the majority of bearings worldwide. Grease can be more than a lubricant; it is often expected to perform as a seal, corrosion inhibitor, shock absorber and a noise suppressant. It is a viscoelastic plastic solid, therefore, a liquid or solid, dependent upon the applied physical conditions of stress and/or temperature, with a yield value, σ o. It has a coarse structure of filaments within a matrix. The suitability of flow properties of a grease for an application is best determined using a controlled stress rheometer for the frequency response of parameters such as yield, σ o, complex shear modulus, G * , phase angle, δ, and the complex viscosity, η *.

  13. Hardness of CaF2 and BaF2 solid lubricants at 25 to 670 deg C

    Deadmore, Daniel L.; Sliney, Harold E.


    Plastic deformation is a prominent factor in determining the lubricating value of solid lubricants. Little information is available and its direct measurement is difficult so hardness, which is an indirect measure of this property was determined for fluoride solid lubricant compositions. The Vickers hardness of BaF2 and CaF2 single crystals was measured up to 670 C in a vacuum. The orientation of the BaF2 was near the (013) plane and the CaF2 was about 16 degrees from the degrees from the (1'11) plane. The BaF2 has a hardness of 83 kg/sq mm at the 25 C and 9 at the 600 C. The CaF2 is 170 at 25 C and 13 at 670 C. The decrease in hardness in the temperature range of 25 to 100 C is very rapid and amounts to 40% for both materials. Melts of BaF2 and CaF2 were made in a platinum crucible in ambient air with compositions of 50 to 100 wt% BaF2. The Vickers hardness of these polycrystalline binary compositions at 25 C increased with increasing CaF2 reaching a maximum of 150 kn/sq mm near the eutectic. The polycrystalline CaF2 was 14% softer than that of the single crystal surface and BsF2 was 30% harder than the single crystal surface. It is estimated that the brittle to ductile transition temperature for CaF2 and BaF2 is less than 100 C for the conditions present in the hardness tester.

  14. Accelerated aging of solid lubricants for the W76-1 TSL : effects of polymer outgassing.

    Dugger, Michael Thomas; Wallace, William O.; Huffman, Elizabeth M.


    The behavior of MoS{sub 2} lubricants intended for the W76-1 TSL was evaluated after 17 and 82 thermal cycles, each lasting seven days and including a low temperature of -35 C and a high temperature of 93 C, in a sealed container containing organic materials. The MoS{sub 2} was applied by tumbling with MoS{sub 2} powder and steel pins (harperized), or by spraying with a resin binder (AS Mix). Surface composition measurements indicated an uptake of carbon and silicon on the lubricant surfaces after aging. Oxidation of the MoS{sub 2} on harperized coupons, where enough MoS{sub 2} was present at the surface to result in significant Mo and S concentrations, was found to be minimal for the thermal cycles in an atmosphere of primarily nitrogen. Bare steel surfaces showed a reduction in friction for exposed coupons compared to control coupons stored in nitrogen, at least for the initial cycles of sliding until the adsorbed contaminants were worn away. Lubricated surfaces showed no more than a ten percent increase in steady-state friction coefficient after exposure. Initial coefficient of friction was up to 250 percent higher than steady-state for AS Mix films on H950 coupons after 82 thermal cycles. However, the friction coefficient exhibited by lubricated coupons was never greater than 0.25, and more often less than 0.15, even after the accelerated aging exposures.

  15. Effect of solid lubricants on friction and wear behaviour of alloyed gray cast iron

    Aravind Vadiraj; M Kamaraj; V S Sreenivasan


    Friction and wear behaviour of MoS2, boric acid, graphite and TiO2 at four different sliding speeds (1.0, 1.5, 2.0, 2.5 m/s) has been compared with dry sliding condition. MoS2 and graphite show 30 to 50% reduction in mass loss compared to other lubricants at all sliding speeds. Friction coefficient reduces with increase in sliding speeds for all the conditions. Friction coefficient of dry as well as lubricant coated samples varies from 0.2 to 0.55 with MoS2 showing the lowest value (0.2). Boric acid and TiO2 coated samples show high friction coefficients at higher sliding speeds due to poor lubricity and adherence. This could also be due to sliding resistance offered by lubricant coated samples with predominant asperities interaction. MoS2 and graphite coated samples also generated lowest frictional temperature compared to other conditions.

  16. Direct verification of the lubrication force on a sphere travelling through a viscous film upon approach to a solid wall

    Marston, Jeremy


    Experiments were performed to observe the motion of a solid sphere approaching a solid wall through a thin layer of a viscous liquid. We focus mainly on cases where the ratio of the film thickness, ℘, to the sphere diameter, D, is in the range 0.03 ℘lubrication theory. Using high-speed video imaging we show, for the first time, that the equations of motion based on the lubrication approximation correctly describe the deceleration of the sphere when St < Stc. Furthermore, we show that the penetration depth at which the sphere motion is first arrested by the viscous force, which decreases with increasing Stokes number, matches well with theoretical predictions. An example for a shear-thinning liquid is also presented, showing that this simple set-up may be used to deduce the short-time dynamical behaviour of non-Newtonian liquids. © 2010 Cambridge University Press.

  17. High-Temperature Solid Lubricant Coating by Plasma Spraying Using Metal-Metal Clad Powders

    Zhang, Tiantian; Lan, Hao; Yu, Shouquan; Huang, Chuanbing; Du, Lingzhong; Zhang, Weigang


    NiCr/Ag-Mo composite coating was fabricated by atmospheric plasma spray technology using clad powders as the feedstock. Its tribological properties at variable temperature were evaluated using a ball-on-disk high-temperature tribometer in air. The results showed that compared with NiCr, the NiCr/Ag-Mo composite coating exhibited better lubrication effect and higher wear resistance at all test temperatures, especially above 600 °C. At 800 °C, NiCr/Ag-Mo composite coating showed the lowest friction coefficient of about 0.2 and its corresponding wear rate reached 2.5 × 10-5 mm3/Nm. Characterizations of NiCr/Ag-Mo composite coating revealed that at temperatures below 400 °C, Ag was smeared and spread onto the wear surface, reducing the friction and wear. At temperature above 500 °C, the Ag2MoO4 lubrication film formed by tribo-oxidation significantly improved the coating's lubrication effect and wear resistance.

  18. Lubrication of Space Systems (c)

    Fusaro, Robert L.


    This article presents an overview of the current state-of-the-art tribology, some current and future perceived space lubrication problem areas, and some potential new lubrication technologies. It is the author's opinion that tribology technology, in general, has not significantly advanced over the last 20 to 30 years, even though some incremental improvements in the technology have occurred. There is a better understanding of elasto-hydrodynamic lubrication, some new lubricating and wear theories have been developed, and some new liquid and solid lubricants have been formulated. However, the important problems of being able to lubricate reliably at high temperatures or at cryogenic temperatures have not been adequately address.

  19. Towards green lubrication in machining

    Liew Yun Hsien, Willey


    The book gives an overview of environmental friendly gaseous and vapour, refrigerated compressed gas, solid lubricant, mist lubrication, minimum quantity lubrication (MQL) and vegetable oils that can be used as lubricants and additives in industrial machining applications. This book introduces vegetable oils as viable and good alternative resources because of their environmental friendly, non-toxic and readily biodegradable nature.  The effectiveness of various types of vegetables oils as lubricants and additives in reducing wear and friction is discussed in this book. Engineers and scientist working in the field of lubrication and machining will find this book useful.

  20. Active lubrication applied to radial gas journal bearings. Part 2: Modelling improvement and experimental validation

    Pierart, Fabián G.; Santos, Ilmar F.


    Actively-controlled lubrication techniques are applied to radial gas bearings aiming at enhancing one of their most critical drawbacks, their lack of damping. A model-based control design approach is presented using simple feedback control laws, i.e. proportional controllers. The design approach...... by finite element method and the global model is used as control design tool. Active lubrication allows for significant increase in damping factor of the rotor-bearing system. Very good agreement between theory and experiment is obtained, supporting the multi-physic design tool developed....

  1. The Preparation and Performances of Self-Dispersed Nanomicron Emulsified Wax Solid Lubricant Ewax for Drilling Fluids

    Feng-shan Zhou


    Full Text Available An oil-in-water nanomicron wax emulsion with oil phase content 45 wt% was prepared by using the emulsifying method of surfactant-in-oil. The optimum prepared condition is 85°C, 20 min, and 5 wt% complex emulsifiers. Then the abovementioned nanomicron emulsifying wax was immersed into a special water-soluble polymer in a certain percentage by the semidry technology. At last, a solidified self-dispersed nanomicron emulsified wax named as Ewax, a kind of solid lubricant for water based drilling fluid, was obtained after dried in the special soluble polymer containing emulsifying wax in low temperature. It is shown that the adhesion coefficient reduced rate (ΔKf is 73.5% and the extreme pressure (E-P friction coefficient reduced rate (Δf is 77.6% when the produced Ewax sample was added to fresh water based drilling fluid at dosage 1.0 wt%. In comparison with other normal similar liquid products, Ewax not only has better performances of lubrication, filtration loss control property, heat resistance, and tolerance to salt and is environmentally friendly, but also can solve the problems of freezing in the winter and poor storage stability of liquid wax emulsion in oilfield applications.

  2. Active lubrication applied to radial gas journal bearings. Part 1: Modeling

    Morosi, Stefano; Santos, Ilmar


    by regulating radial injection of lubricant through the means of piezoelectric actuators mounted on the back of the bearing sleeves. A feedback law is used to couple the dynamic of a simplified rotor-bearing system with the pneumatic and dynamic characteristics of a piezoelectric actuated valve system. Selected...

  3. Functional regulation of Pb-Ti/MoS2 composite coatings for environmentally adaptive solid lubrication

    Ren, Siming; Li, Hao; Cui, Mingjun; Wang, Liping; Pu, Jibin


    The lubrication of molybdenum disulfide coatings has commonly been limited by the application environments, for instance, the crystal MoS2 are easily affected by water to form MoO3 that causes a higher friction coefficient and short lifetime. Therefore, to improve the tribolgical performance of MoS2 in high humidity condition, the co-doped Pb-Ti/MoS2 composite coatings are deposited by unbalanced magnetron sputtering system. The design of the co-doping elements in MoS2-based coatings can not only maintain the characteristic of low humidity-sensitivity as the Ti/MoS2 coating but also improve the mechanical properties and tribological performance of coatings as a comparison with single-doped ones. Moreover, the ultra-low friction coefficient with a minimum value of 0.006 under the vacuum condition is achieved for Pb-Ti/MoS2 composite coating containing about 4.6 at.% Pb, depending on the densification structure of coating. Intriguingly, the wear behaviours of Pb-Ti/MoS2 composite coatings are in accordance with the variation in H/E (hardness to the elastic modulus) ratio that the coating with higher H/E exhibits lower wear rate. These results demonstrate that the lubricating properties of MoS2 coatings in both humid environment and vacuum condition can be achieved through the Pb and Ti co-doped, which is of great significant for developing MoS2 coatings as the environmentally adaptive lubricants.

  4. The Effect of Compositional Tailoring on the Thermal Expansion and Tribological Properties of PS300: A Solid Lubricant Composite Coating

    DellaCorte, C.; Fellenstein, J. A.


    This paper describes a research program in which the goal is to alter the thermal expansion coefficient of a composite solid lubricant coating, PS300, by compositional tailoring. PS300 is a plasma sprayed coating consisting of chrome oxide, silver and barium fluoride/calcium fluoride eutectic in NiCr binder. By adjusting the composition, the thermal expansion coefficient can be altered, and hence chosen, to more closely match a selected substrate preventing coating spallation at extreme temperatures. Thermal expansion coefficients (CTE) for a variety of compositions were measured from 25 to 800 C using a commercial dilatometer. The CTE's ranged from 7.0 to 13 x lO(exp -6)/deg C depending on the binder content. Subsequent tribological testing of a modified composition indicated that friction and wear properties were relatively insensitive to compositional tailoring.

  5. The effect of temperature and solid concentration on dynamic viscosity of MWCNT/MgO (20–80)–SAE50 hybrid nano-lubricant and proposing a new correlation: An experimental study

    Asadi, Amin; Asadi, Meisam; Rezaei, Mohammadhosein


    -lubricant shows Newtonian behavior in all the studied temperatures and solid concentrations. Furthermore, the experimental results showed that the dynamic viscosity decreased as the temperature increased. It is also revealed that increasing the solid concentration leads to increasing the dynamic viscosity...... on the experimental data, a new model to predict the dynamic viscosity of the studied nano-lubricant in terms of temperature and solid concentration has been proposed....

  6. Influence of the Lubricant Type on the Surface Quality of Steel Parts Obtained by Ironing

    D. Adamović


    Full Text Available If it is needed to achieve a higher strain rate during the ironing process, which is possible without inter-stage annealing, the ironing is performed in succession through multiple dies. During that process, changes of friction conditions occur due to the change of contact conditions (dislodging of lubricants, changes of surface roughness, formation of friction junctions, etc.. In the multistage ironing, after each stage, the completely new conditions on the contact surfaces occur, which will significantly affect the quality of the workpiece surface. Lubricant has a very important role during the steel sheet metal ironing process; to separate the sheet metal surface from the tool and to reduce the friction between the contact surfaces. The influence of tribological conditions in ironing process is extremely important and it was a subject of study among researches in recent years, both in the real processes and on the tribo-models. Investigation of tribological conditions in the real processes is much longer and more expensive, so testing on the tribo-models is more frequent. Experimental research on the original tribo-model presented in this paper was aimed to indicate the changes that occur during multistage ironing, as well as to consider the impact of some factors (tool material, lubricant on die and punch on increase or decrease of the sheet metal surface roughness in ironing stages.

  7. Pulsed Plasma Lubrication Device and Method

    Hofer, Richard R. (Inventor); Bickler, Donald B. (Inventor); D'Agostino, Saverio A. (Inventor)


    Disclosed herein is a lubrication device comprising a solid lubricant disposed between and in contact with a first electrode and a second electrode dimensioned and arranged such that application of an electric potential between the first electrode and the second electrode sufficient to produce an electric arc between the first electrode and the second electrode to produce a plasma in an ambient atmosphere at an ambient pressure which vaporizes at least a portion of the solid lubricant to produce a vapor stream comprising the solid lubricant. Methods to lubricate a surface utilizing the lubrication device in-situ are also disclosed.

  8. Lubrication system

    Wadding, C.; Lagasse, N.L.; Milo, G.T.; Vankamerik, J.G.


    This patent describes a lubrication system for controlling the flow of lubricant as a function of the altitude at which a gas turbine engine is operating. This lubrication system is comprised of: 1.) A source of lubricant under pressure; 2.) A unit requiring lubrication; 3.) A movable valve in fluid communication with the source and with the unit for regulating the flow of lubricant from the source to the unit; and 4.) An altitude sensor associated with the movable valve for positioning the movable valve to control the flow of lubricant from the source to the unit, as a function of the altitude at which the engine is operating.

  9. Friction behaviour of solid oxide lubricants as second phase in alpha-Al2O3 and stabilised ZrO2 composites

    Kerkwijk, B.; de la Luz Garcia-Curiel, M.M.; van Zyl, W.E.; Winnubst, Aloysius J.A.; Mulder, E.J.; Schipper, Dirk J.; Verweij, H.


    The influence of metal oxide additives within alumina (¿-Al2O3) and yttria-stabilised tetragonal zirconia (Y-TZP) matrices was studied with respect to the tribological behaviour of the composites. The solid lubricants CuO, ZnO, MgO, MnO2 and B2O3 were added in sufficiently small quantities (1 or 5

  10. Lubricant composition

    Baile, G.H.


    Lubricating compositions and shaped articles composed thereof are described which consist essentially of about 30 to about 60% by weight of an oil of lubricating viscosity, about 20 to about 50% by weight of a high molecular weight polymer, and about 20 about 50% by weight of a heat conductive agent capable of conducting heat away from a bearing surface where it is generated. The high molecular weight polymer may, for example, be polyethylene, having average molecular weights in the range from about 1.0 X 105 to about 5.0 X 106. The oil may be a mineral oil, a diester oil or preferably a synthetic hydrocarbon oil having a viscosity in the range from about 13 to about 1200 mm''/s (Mm2/s) at 38/sup 0/C. (100/sup 0/F.) the heat conductive agent may be powdered zinc oxide, aluminum powder, or equivalents thereof in this invention. The compositions are semi-rigid gels which may be formed in a mold and used as is, or which may be shaped further after molding. The gels are formed by blending the heat conductive agent and polymer and then blending that mixture with the oil and heating to a temperature above the softening temperature of the polymer for a period of time (About 5 to about 75 minutes) sufficient that the mixture will form a firm, tough solid gel on cooling having an oily surface provided by oil exuding from the gel thus producing a lubricative mass operable for extended periods of time. The heat conductive substance dispersed in the gel aids in dissipating heat produced at the bearing surfaces during use thus improving the performance of the gel both in withstanding higher bulk operating temperatures and in resisting breakdown of the gel under prolonged use.

  11. Analysis on mechanism of thin film lubrication

    ZHANG Chaohui; LUO Jianbin; HUANG Zhiqiang


    It is an important concern to explore the properties and principles of lubrication at nano or molecularscale. For a long time, measurement apparatus for filmthickness of thin film lubrication (TFL) at nano scale havebeen devised on the basis of superthin interferometry technique. Many experiments were carried out to study the lubrication principles of TFL by taking advantages of aforementioned techniques, in an attempt to unveil the mechanism of TFL. Comprehensive experiments were conducted to explore the distinctive characteristics of TFL. Results show that TFL is a distinctive lubrication state other than any known lubrication ones, and serves as a bridge between elastohydrodynamic lubrication (EHL) and boundary lubrication (BL). Two main influence factors of TFL are the solid surface effects and the molecular properties of the lubricant, whose combination effects result in alignment of liquid molecules near the solid surfaces and subsequently lubrication with ordered film emerged. Results of theoretical analysis considering microstructure are consistent with experimental outcomes, thus validating the proposed mechanism.

  12. Carbon-based tribofilms from lubricating oils

    Erdemir, Ali; Ramirez, Giovanni; Eryilmaz, Osman L.; Narayanan, Badri; Liao, Yifeng; Kamath, Ganesh; Sankaranarayanan, Subramanian K. R. S.


    Moving mechanical interfaces are commonly lubricated and separated by a combination of fluid films and solid 'tribofilms', which together ensure easy slippage and long wear life(1). The efficacy of the fluid film is governed by the viscosity of the base oil in the lubricant; the efficacy of the solid tribofilm, which is produced as a result of sliding contact between moving parts, relies upon the effectiveness of the lubricant's anti-wear additive (typically zinc dialkyldithiophosphate)(2). Minimizing friction and wear continues to be a challenge, and recent efforts have focused on enhancing the anti-friction and anti-wear properties of lubricants by incorporating inorganic nanoparticles and ionic liquids(3,4). Here, we describe the in operando formation of carbon-based tribofilms via dissociative extraction from base-oil molecules on catalytically active, sliding nanometre-scale crystalline surfaces, enabling base oils to provide not only the fluid but also the solid tribofilm. We study nanocrystalline catalytic coatings composed of nitrides of either molybdenum or vanadium, containing either copper or nickel catalysts, respectively. Structurally, the resulting tribofilms are similar to diamond-like carbon(5). Ball-on-disk tests at contact pressures of 1.3 gigapascals reveal that these tribofilms nearly eliminate wear, and provide lower friction than tribofilms formed with zinc dialkyldithiophosphate. Reactive and ab initio molecular-dynamics simulations show that the catalytic action of the coatings facilitates dehydrogenation of linear olefins in the lubricating oil and random scission of their carbon-carbon backbones; the products recombine to nucleate and grow a compact, amorphous lubricating tribofilm.

  13. Investigation of the Thermal Stability and Tribological Behavior of Nickel-oxythiomolybdate as Solid Lubricant or Lubricating Oil Additive%硫代钼酸镍的热稳定性及其摩擦学性能研究

    陈金荣; 李曙; 叶萍萍; 姜晓霞; 李诗卓; 杨生荣


    采用X射线衍射和电子探针鉴定了硫代钼酸镍的结构及其经不同温度加热或高温摩擦磨损试验后磨损表面产物的结构和成分,用热重法对其热稳定性进行了评价.在四球摩擦磨损试验机和销-盘式高温摩擦磨损试验机上考察了其作为油品添加剂及固体润滑剂的摩擦学特性,探讨了其作为固体润滑剂在升温过程中可能发生的化学变化及其对润滑性能的影响.结果表明:硫代钼酸镍在氮气流中表现出较好的热稳定性,在空气中于350℃左右开始发生氧化分解;其高温氧化分解产物MoO3和MoS2具有明显的减摩作用,因此硫代钼酸镍可用作室温到高温(20~800℃)下的固体润滑剂.%The thermal stability of nickel oxythiomolybdate (NiMoO2S2) andthe elemental composition of its thermally decomposed products were examined by means of electron probe micro-analysis and thermal gravimetric analysis (TGA). The tribological behavior of NiMoO2S2 powder as a solid lubricant or lubricating oil additive was investigated on a pin-on-disc friction and wear tester and a four-ball machine. As the results, NiMoO2S2 shows good thermal stability in N2, while it starts to decompose at 350 ℃ in air. It has good friction-reduction and antiwear ability either as a solid lubricant or lubricating oil additive at elevated temperature. This is attributed to its tribochemical products MoO3 and MoS2 during high temperature friction and wear test.

  14. Dairy Equipment Lubrication


    Lake To Lake Dairy Cooperative, Manitowoc, Wisconsin, operates four plants in Wisconsin for processing milk, butter and cheese products from its 1,300 member farms. The large co-op was able to realize substantial savings by using NASA information for improved efficiency in plant maintenance. Under contract to Marshall Space Flight Center, Midwest Research Institute compiled a handbook consolidating information about commercially available lubricants. The handbook details chemical and physical properties, applications, specifications, test procedures and test data for liquid and solid lubricants. Lake To Lake's plant engineer used the handbook to effect savings in maintenance labor and materials costs by reducing the number of lubricants used on certain equipment. Strict U.S. Department of Agriculture and Food and Drug Administration regulations preclude lubrication changes n production equipment, but the co-op's maintenance chief was able to eliminate seven types of lubricants for ancillary equipment, such as compressors and high pressure pumps. Handbook data enabled him to select comparable but les expensive lubricants in the materials consolidation process, and simplified lubrication schedules and procedures. The handbook is in continuing use as a reference source when a new item of equipment is purchased.

  15. Numerical calculation of lubrication methods and programs

    Huang, Ping


    This book describes basic lubrication problems and specific engineering applications. It focuses on the Reynolds equation, illustrating solutions with different conditions and discrete forms, such as dynamic bearing or grease lubrication. Thermal fluid lubrication problems are addressed by combining the Reynolds and energy equation solution, while the topic of elastohydrodynamic lubrication illustrates a combination of programs, join solution methods, and the Reynolds equation. Additional programs address lubrication for different parts with specific design, such as the magnetic hard disk/head


    Minnesota State Dept. of Education, St. Paul. Div. of Vocational and Technical Education.


  17. Environmental assessment of lubricants before and after wire drawing process.

    Ruiz, M C; Verde, J; Andrés, A; Viguri, J; Irabien, A


    Iron wire drawing processes involve the use of solid lubricants made of powdered raw materials, which lead to industrial wastes after being used. These wastes, based on stearates, have a negative effect on the environment. This study deals with the environmental assessment of some lubricants before and after the wire drawing process in a Spanish factory. The parameters evaluated for this study have been total organic carbon (TOC), mobility of zinc and lead, and ecotoxicity (EC(50)). Results show that wastes have more ecotoxicity than the original lubricants due to the content of metals that lubricants pick up from the wire, as pickling, patenting and galvanising take part in the manufacture. The capture of metallic particles leads to a reduction of TOC and an increase in ecotoxicity.

  18. Lubrication: no problemexclamation

    Leugner, L.O.


    The oilsand at Syncrude's mine at Fort McMurray, Alberta is loaded onto conveyors by four Krupp bucketwheel reclaimers. Operating conditions are very harsh, and in 1983, four bucketwheel roller bearings failed, resulting in significant production losses. As part of solving this problem, a unique semi-synthetic lithium-complex-thickened grease was developed to lubricate the bearings. The new lubricant, called EPIC EP102, allows startup motion at temperatures as low as -45/sup 0/C, while providing long lubrication life in sustained service up to 150/sup 0/C. Since the new grease was installed, Syncrude has experienced no bearing failures. 1 fig.

  19. 两种粘结固体润滑涂层的研究及应用%An Investigation and Application of Two Kinds of Bonded Solid Lubrication Films

    胡丽天; 周惠娣; 冶银平; 陈建敏


    Two types of bonded solid lubrication films were prepared : (1) A heat-resisting bonded solid lubrication film. (2) A high load-carrying bonded solid lubrication film. The thermal stability,load-carrying capacity,adhesion, flexibility and shock-resistance were investigated. Results indicate that the heat-resisting bonded solid lubrication film is stable even at a temperature of 300℃,The high load-carrying bonded solid lubrication film is able to work at high load. The two kinds of solid lubrication films can be used for lubricating worms and journal bearings which work at high temperature and high load.%介绍了2种粘结固体润滑涂层的研制及其应用:① 耐高温粘结固体润滑涂层,这种涂层可以在300 ℃下长期使用,400 ℃下短期使用,解决运动部件高温条件下的润滑和磨损问题。 ② 高承载粘结固体润滑涂层。研究表明,这种粘结固体润滑涂层承载能力高,能够在普通润滑油难以承受的载荷下 (如PV值高达4 900 N.m/s的运行工况) 起到良好的润滑作用。

  20. Developments and unsolved problems in nano-lubrication*


    The main achievements in the area of nano liquid film, e.g. the distinction between different lubrication regimes, properties of thin film lubrication, the transition between liquid and solid state, ordered and disordered state, the failure of thin lubricant film, the equivalent viscosity and flowing characteristics of micro-fluid, the influence of solid surfaces on nano-lubrication, thin film lubrication of polymer, superlubricity, have been reviewed and some unsolved problems are discussed.

  1. Research on Friction Property of WS2 Matrix Solid Lubricating Coatings%WS2基固体润滑涂层摩擦性能研究

    侯锁霞; 高辉; 贾晓鸣


    The tribological properties of WS2 matrix solid lubricating coating were investigated by friction and wear tests.The results show that,under normal temperature,the tribological coefficient of WS2 matrix solid lubricating coatings are close to that of MoS2 matrix solid lubricating coating,however,the coating quality of WS2 metal matrix is inferior to that of MoS2 ; under high temperature,WS2 matrix coatings have stable friction coefficient,the tribological properties of WS2 coatings are superior to MoS2 matrix solid lubricating coatings.The composite coatings including MoS2,WS2 and Sb2 O3 can play a better role in friction reducing and lubrication,and the friction coefficient can reach to 0.045 under high temperature of 400℃.For the composite coatings including MoS2,WS2 and Sb2 O3,Sb2 O3 reacts preferentially with the oxygen in the air under high temperature,which slows down the oxidation rate of MoS2 and WS2,and elevates the temperature that MoS2 and WS2 can withstand.In the condition of boundary lubrication,the mixed films of FeS and MoS2 are generated by the electrochemical catalysis and heat friction chemical reaction of MoS2,which improves the boundary lubrication.%通过摩擦磨损试验,研究WS2固体润滑剂的摩擦性能.结果表明:常温工况下,WS2固体润滑剂的摩擦因数与MoS2的相近,但WS2涂层在金属基上成膜状态不如MoS2涂层;高温工况下,WS2基涂层摩擦因数稳定,摩擦性能优于MoS2基固体润滑涂层;在400℃的温度条件下,WS2、MoS2、Sb2 O3复合涂层摩擦因数可达0.045,减摩润滑作用显著提高.在高温工况下,WS2、MoS2、Sb2O3复合涂层中Sb2O3优先与空气中的氧发生反应从而减缓MoS2、WS2的氧化速度,提高MoS2、WS2所能承受的温度;在边界润滑条件下,MoS2发生电化学催化和热摩擦化学反应,生成FeS和MoS2混合膜,改善了边界润滑.

  2. Solid dispersions in pharmaceutical technology. Part I. Classification and methods to obtain solid dispersions.

    Karolewicz, Bozena; Górniak, Agata; Probst, Sandra; Owczarek, Artur; Pluta, Janusz; Zurawska-Płaksej, Ewa


    There are many methods to increase solubility of a substance. These include, inter alia, preparation of solid dispersions, i.e. eutectic mixtures, solid solutions, glassy solutions and suspensions. When compared to the individual constituents prior to dispersion formation solid dispersion components are better soluble in water. Therefore, solid solutions became one of the most promising ways to modify solubility, ensuring improved bioavailability and consequently therapeutic efficacy of a substance. In this part of the publication solid dispersions were classified and described in regard to their properties and preparation methods, i.e. melting method, melt evaporation and melt extrusion methods, lyophilisation technique, melt agglomeration process as well as SCF technology and electrospinning.

  3. Influence of lubrication forces in direct numerical simulations of particle-laden flows

    Maitri, Rohit; Peters, Frank; Padding, Johan; Kuipers, Hans


    Accurate numerical representation of particle-laden flows is important for fundamental understanding and optimizing the complex processes such as proppant transport in fracking. Liquid-solid flows are fundamentally different from gas-solid flows because of lower density ratios (solid to fluid) and non-negligible lubrication forces. In this interface resolved model, fluid-solid coupling is achieved by incorporating the no-slip boundary condition implicitly at particle's surfaces by means of an efficient second order ghost-cell immersed boundary method. A fixed Eulerian grid is used for solving the Navier-Stokes equations and the particle-particle interactions are implemented using the soft sphere collision and sub-grid scale lubrication model. Due to the range of influence of lubrication force on a smaller scale than the grid size, it is important to implement the lubrication model accurately. In this work, different implementations of the lubrication model on particle dynamics are studied for various flow conditions. The effect of a particle surface roughness on lubrication force and the particle transport is also investigated. This study is aimed at developing a validated methodology to incorporate lubrication models in direct numerical simulation of particle laden flows. This research is supported from Grant 13CSER014 of the Foundation for Fundamental Research on Matter (FOM), which is part of the Netherlands Organisation for Scientific Research (NWO).

  4. Carbon-based tribofilms from lubricating oils

    Erdemir, Ali; Ramirez, Giovanni; Eryilmaz, Osman L.; Narayanan, Badri; Liao, Yifeng; Kamath, Ganesh; Sankaranarayanan, Subramanian K. R. S.


    Moving mechanical interfaces are commonly lubricated and separated by a combination of fluid films and solid ‘tribofilms’, which together ensure easy slippage and long wear life. The efficacy of the fluid film is governed by the viscosity of the base oil in the lubricant; the efficacy of the solid tribofilm, which is produced as a result of sliding contact between moving parts, relies upon the effectiveness of the lubricant’s anti-wear additive (typically zinc dialkyldithiophosphate). Minimizing friction and wear continues to be a challenge, and recent efforts have focused on enhancing the anti-friction and anti-wear properties of lubricants by incorporating inorganic nanoparticles and ionic liquids. Here, we describe the in operando formation of carbon-based tribofilms via dissociative extraction from base-oil molecules on catalytically active, sliding nanometre-scale crystalline surfaces, enabling base oils to provide not only the fluid but also the solid tribofilm. We study nanocrystalline catalytic coatings composed of nitrides of either molybdenum or vanadium, containing either copper or nickel catalysts, respectively. Structurally, the resulting tribofilms are similar to diamond-like carbon. Ball-on-disk tests at contact pressures of 1.3 gigapascals reveal that these tribofilms nearly eliminate wear, and provide lower friction than tribofilms formed with zinc dialkyldithiophosphate. Reactive and ab initio molecular-dynamics simulations show that the catalytic action of the coatings facilitates dehydrogenation of linear olefins in the lubricating oil and random scission of their carbon-carbon backbones; the products recombine to nucleate and grow a compact, amorphous lubricating tribofilm.

  5. Consolidation of titanium hydride powders during the production of titanium PM parts: The effect of die wall lubricants

    Machio, Christopher N


    Full Text Available under vacuum at various sintering temperatures in order to determine the effect of the lubricants on oxygen content, phase compositions, microstructures and hardness of the sintered components. The results indicate that there is an immediate improvement...

  6. Lubrication a practical guide to lubricant selection

    Lansdown, A R


    Lubrication: A Practical Guide to Lubricant Selection provides a guide to modern lubrication practice in industry, with emphasis on practical application, selection of lubricants, and significant factors that determine suitability of a lubricant for a specific application. Organized into 13 chapters, this book begins with a brief theoretical opening chapter on the basic principles of lubrication. A chapter then explains the choice of lubricant type, indicating how to decide whether to use oil, grease, dry lubricant, or gas lubrication. Subsequent chapters deal with detailed selection of lubric

  7. A friction model for cold forging of aluminum, steel and stainless steel provided with conversion coating and solid film lubricant

    Bay, Niels; Eriksen, Morten; Tan, Xincai


    Adopting a simulative tribology test system for cold forging the friction stress for aluminum, steel and stainless steel provided with typical lubricants for cold forging has been determined for varying normal pressure, surface expansion, sliding length and tool/work piece interface temperature...... of normal pressure and tool/work piece interface temperature. The model is verified by process testing measuring friction at varying reduction in cold forward rod extrusion....

  8. Developments in lubricant technology

    Srivastava, S P


    Provides a fundamental understanding of lubricants and lubricant technology including emerging lubricants such as synthetic and environmentally friendly lubricants Teaches the reader to understand the role of technology involved in the manufacture of lubricants Details both major industrial oils and automotive oils for various engines Covers emerging lubricant technology such as synthetic and environmentally friendly lubricants Discusses lubricant blending technology, storage, re-refining and condition monitoring of lubricant in equipment

  9. Quantum theory of the solid state part B

    Callaway, Joseph


    Quantum Theory of the Solid State, Part B describes the concepts and methods of the central problems of the quantum theory of solids. This book discusses the developed machinery applied to impurities, disordered systems, effects of external fields, transport phenomena, and superconductivity. The representation theory, low field diamagnetic susceptibility, electron-phonon interaction, and Landau theory of fermi liquids are also deliberated. This text concludes with an introduction to many-body theory and some applications. This publication is a suitable textbook for students who have completed

  10. Graphene: a new emerging lubricant

    Diana Berman


    Full Text Available In recent years, reducing friction and wear-related mechanical failures in moving mechanical systems has gained increased attention due to friction's adverse impacts on efficiency, durability, and environmental compatibility. Accordingly, the search continues for novel materials, coatings, and lubricants (both liquid and solid that can potentially reduce friction and wear. Despite intense R&D efforts on graphene for a myriad of existing and future applications, its tribological potential as a lubricant remains relatively unexplored. In this review, we provide an up-to-date survey of recent tribological studies based on graphene from the nano-scale to macro-scale, in particular, its use as a self-lubricating solid or as an additive for lubricating oils.

  11. Marine Lubricants

    Carter, B. H.; Green, D.

    Marine diesel engines are classified by speed, either large (medium speed) or very large (slow speed) with high efficiencies and burning low-quality fuel. Slow-speed engines, up to 200 rpm, are two-stroke with separate combustion chamber and sump connected by a crosshead, with trunk and system oil lubricants for each. Medium-speed diesels, 300-1500 rpm, are of conventional automotive design with one lubricant. Slow-speed engines use heavy fuel oil of much lower quality than conventional diesel with problems of deposit cleanliness, acidity production and oxidation. Lubricants are mainly SAE 30/40/50 monogrades using paraffinic basestocks. The main types of additives are detergents/dispersants, antioxidants, corrosion inhibitors, anti-wear/load-carrying/ep, pour-point depressants and anti-foam compounds. There are no simple systems for classifying marine lubricants, as for automotive, because of the wide range of engine design, ratings and service applications they serve. There are no standard tests; lubricant suppliers use their own tests or the Bolnes 3DNL, with final proof from field tests. Frequent lubricant analyses safeguard engines and require standard sampling procedures before determination of density, viscosity, flash point, insolubles, base number, water and wear metal content.

  12. Advanced Lubricants


    Three Sun Coast Chemicals (SCC) of Daytona, Inc. products were derived from NASA technology: Train Track Lubricant, Penetrating Spray Lube, and Biodegradable Hydraulic Fluid. NASA contractor Lockheed Martin Space Operations contacted SCC about joining forces to develop an environmentally safe spray lubricant for the Shuttle Crawler. The formula was developed over an eight-month period resulting in new products which are cost effective and environmentally friendly. Meeting all Environmental Protection Agency requirements, the SCC products are used for applications from train tracks to bicycle chains.

  13. Lubrication Flows.

    Papanastasiou, Tasos C.


    Discusses fluid mechanics for undergraduates including the differential Navier-Stokes equations, dimensional analysis and simplified dimensionless numbers, control volume principles, the Reynolds lubrication equation for confined and free surface flows, capillary pressure, and simplified perturbation techniques. Provides a vertical dip coating…

  14. Glass molding process with mold lubrication

    Davey, Richard G.


    Improvements are provided in glass forming processes of the type wherein hot metal blank molds are employed by using the complementary action of a solid film lubricant layer, of graphite dispersed in a cured thermoset organopolysiloxane, along with an overspray of a lubricating oil.

  15. Evaluation of Vitreous and Devitrifying Enamels as Hot Forming Lubricants for Aluminum AA5083 Alloy

    Riahi, A. R.; Morales, A. T.; Alpas, A. T.


    The adhesion of aluminum to tool surfaces during the hot forming of sheet aluminum alloys presents challenging tribological problems. Graphite and boron nitride are commonly used as aluminum adhesion mitigating solid lubricants for hot forming processes, but lubricant breakdown in high-stress areas, such as corners and bends, remains an issue compromising the quality of the formed parts as well as the tool life. Low-melting temperature enamels may provide an affordable and easy to apply alternative. In this study, vitreous (amorphous glass) and devitrifying (two phase crystalline glass) layers were deposited on the surface of sheet aluminum samples with a sedimentation technique. Enamel lubrication was effective in preventing aluminum transfer to the steel counterface. Hence, the prospect exists for the use of these enamels as aluminum workpiece lubricants in hot forming operations.

  16. Characteristics of lubrication at nanoscale in two-phasefluid system

    ZHANG; Chaohui(张朝辉); WEN; Shizhu(温诗铸); LUO; Jianbin(雒建斌)


    Thin film lubrication (TFL) is a condition in which the lubricating features between two surfaces in relative motion are determined by the combination of the properties of the surfaces and the lubricant and viscosity of the lubricant. The effects imposed by couple stress on lubrication characteristics cannot be disregarded in this regime where the ordered molecules dominate the fluid field. There are different tensor measures and constitutive equations in this case other than Newtonian case. The lubrication of two-phase (solid phase and liquid phase) fluid is investigated in this paper. The existence of couple stress will enhance the lubricant viscosity and hence increase the film thickness and improve the load-carrying capability. Size-dependent effects can be seen in the lubrication with couple stress, and the thinner the lubricating film is, the more obvious the effect will be.

  17. Solid dispersion in pharmaceutical technology. Part II. The methods of analysis of solid dispersions and examples of their application.

    Karolewicz, Bozena; Górniak, Agata; Owczarek, Artur; Nartowski, Karol; Zurawska-Płaksej, Ewa; Pluta, Janusz


    In the first part of the article solid dispersions were classified the properties and methods of their preparation were described. This section presents methods of analysis of solid dispersions i.e.: thermoanalytical methods, XRPD, FTIR, microscopic methods, dissolution studies and examples of drug forms where solid dispersions were used.

  18. Soft ceramics for high temperature lubrication: graphite-free lubricants for hot and warm forging of steel

    Gonzalez Rodriguez, Pablo


    The main research focus of this thesis is on the development of the next generation of solid lubricants for high temperature forming of steel. These lubricants are based on ceramic nanoparticles which are more resistant to temperature and oxidation than traditional lubricants. Nowadays, the most com

  19. Soft ceramics for high temperature lubrication: graphite-free lubricants for hot and warm forging of steel

    Gonzalez Rodriguez, P.


    The main research focus of this thesis is on the development of the next generation of solid lubricants for high temperature forming of steel. These lubricants are based on ceramic nanoparticles which are more resistant to temperature and oxidation than traditional lubricants. Nowadays, the most

  20. 计入固液界面作用的润滑热力学模型与分析∗%Thermo dynamic analysis of lubrication considering solid-liquid interface interaction

    经昊达; 张向军; 田煜; 孟永钢


    Friction or lubrication process is a typical process of the energy dissipation. It can be reasonably described and speculated by using the entropy increase and dissipative structure theory of the non-equilibrium thermodynamics. In this paper, we model and analyze the typical thin-film lubrication mechanism based on the theory of thermodynamics, by using the interfacial disjoining pressure to characterize the dominant role of the solid-lubricant interaction on a microscale and establishing the lubrication Stribeck curve based on thermodynamic concepts. The concept of entropy production is adopted to describe the lubrication system, which is defined as the sum of multiplications of the thermodynamic forces and flows. Then the variations and the competing relations between the pairs of thermodynamic forces and flows could be used to reveal the different factors dominated in the lubrication system, such as the solid-liquid interaction, the sliding velocity, and the normal load. In this paper, we assume that all the dissipated energy caused by the viscous resistance of lubricant is converted into heat, then the total entropy increase per surface area at the frictional interface is considered, affected by interfacial disjoining pressure and the one-dimensional heat flow. With the entropy increasing analysis of lubrication process, we find that when the entropy production in the steady state becomes minimum, the total energy dissipation due to friction also becomes minimum, which directly indicates the lowest friction coefficient point at the lubrication Stribeck curve. Moreover, when a lubrication system loses its stability slightly from the equilibrium state, self-organization may occur at the solid-lubricant interface, thus resulting in partially ordering interfacial structures, which may indicate the interfacial structures when tribosystem turns from hydrodynamic lubrication phase into thin-film lubrication phase. In the experimental aspect, the location of the lowest

  1. On the Effect of Lubricant on Pool Boiling Heat Transfer Performance


    Â Â Â For typical vapor compression processes, lubricant oil is very essential for lubricating and sealing the sliding parts and the lubricant also takes part in cushioning cylinder valves. However lubricants may migrate to the evaporator to alter the heat transfer characteristics. This is can be made clear from the viscosity and surface tension of lubricant since the viscosity of lubricant oil is about two to three orders higher than that of refrigerant whereas the corresponding surface t...

  2. Aviation Lubricants

    Lansdown, A. R.; Lee, S.

    Aviation lubricants must be extremely reliable, withstand high specific loadings and extreme environmental conditions within short times. Requirements are critical. Piston engines increasingly use multi-grade oils, single grades are still used extensively, with anti-wear and anti-corrosion additives for some classes of engines. The main gas turbine lubricant problem is transient heat exposure, the main base oils used are synthetic polyol esters which minimise thermal degradation. Aminic anti-oxidants are used together with anti-wear/load-carrying, corrosion inhibitor and anti-foam additives. The majority of formulation viscosities are 5 cSt at 100°C. Other considerations are seal compatibility and coking tendency.

  3. Liquid lubrication for space applications

    Fusaro, Robert L.; Khonsari, Michael M.


    Reviewed here is the state of the art of liquid lubrication for space applications. The areas discussed are types of liquid lubrication mechanisms, space environmental effects on lubrication, classification of lubricants, liquid lubricant additives, grease lubrication, mechanism materials, bearing anomalies and failures, lubricant supply techniques, and application types and lubricant needs for those applications.

  4. Rheology in lubrication

    Cheng, H. S.


    The rheological effects on lubrication are discussed. The types of lubrication considered are thick film hydrodynamic lubrication and thin film elastohydrodynamic lubrication. The temperature-viscosity, viscoelastic, shear-thinning, and normal stess effects on the lubrication of journal bearings are analyzed. A graph of the pressure distribution of viscoelastic liquids in journal bearings is provided. Mathematical models are developed to define the effects of various properties of the lubricants on friction reduction.

  5. Lubrication Of Nonconformal Contacts

    Jeng, Yeau-Ren


    Report discusses advances in knowledge of lubrication of nonconformal contacts in bearings and other machine elements. Reviews previous developments in theory of lubrication, presents advances in theory of lubrication to determine minimum film thickness, and describes experiments designed to investigate one of regimes of lubrication for ball bearings.

  6. Mass, energy and material balances of SRF production process. Part 3: solid recovered fuel produced from municipal solid waste.

    Nasrullah, Muhammad; Vainikka, Pasi; Hannula, Janne; Hurme, Markku; Kärki, Janne


    This is the third and final part of the three-part article written to describe the mass, energy and material balances of the solid recovered fuel production process produced from various types of waste streams through mechanical treatment. This article focused the production of solid recovered fuel from municipal solid waste. The stream of municipal solid waste used here as an input waste material to produce solid recovered fuel is energy waste collected from households of municipality. This article presents the mass, energy and material balances of the solid recovered fuel production process. These balances are based on the proximate as well as the ultimate analysis and the composition determination of various streams of material produced in a solid recovered fuel production plant. All the process streams are sampled and treated according to CEN standard methods for solid recovered fuel. The results of the mass balance of the solid recovered fuel production process showed that 72% of the input waste material was recovered in the form of solid recovered fuel; 2.6% as ferrous metal, 0.4% as non-ferrous metal, 11% was sorted as rejects material, 12% as fine faction and 2% as heavy fraction. The energy balance of the solid recovered fuel production process showed that 86% of the total input energy content of input waste material was recovered in the form of solid recovered fuel. The remaining percentage (14%) of the input energy was split into the streams of reject material, fine fraction and heavy fraction. The material balances of this process showed that mass fraction of paper and cardboard, plastic (soft) and wood recovered in the solid recovered fuel stream was 88%, 85% and 90%, respectively, of their input mass. A high mass fraction of rubber material, plastic (PVC-plastic) and inert (stone/rock and glass particles) was found in the reject material stream. © The Author(s) 2014.

  7. Micro-Plasto-Hydrodynamic Lubrication a Fundamental Mechanism in Cold Rolling

    Laugier, Maxime; Boman, Romain; Legrand, Nicolas


    This paper presents recent investigations in Micro-Plasto-Hydrodynamic (MPH) lubrication. Industrial evidences of the existence of MPH lubrication mechanism for cold rolling processes are presented. A new lubrication model developed for strip drawing processes is then applied to predict the MPH...... lubrication initiation and MPH lubrication extension along the tool-piece solid contacts initially in boundary lubrication regime. Finally, it is shown how this new MPH lubrication model can be implemented in a cold rolling model to maximize mills capabilities, determine optimum rolling oils properties...

  8. Research on the Performance of Solid Lubricating Coating Tool Based on DEFORM-3 D%基于 DEFORM-3 D的固体润滑涂层刀具性能研究

    侯锁霞; 高辉; 贾晓鸣


    基于固体润滑技术、刀具热传导理论以及网格重划技术,建立了刀具-工件的DEFORM-3D有限元模型,对MoS2、WS2、Sb2 O3固体润滑涂层的高速钢刀具切削加工过程进行仿真。通过与切削试验的对比,验证了不同进给量、切削深度下的切削力、切削温度变化规律的仿真结果的准确性。结果表明:该固体润滑涂层应用于中低速干切削中,可有效降低切削热和切削力、延长刀具使用寿命。%Basing on solid lubrication technology,tool thermal conduction theory and remeshing technique,DEFORM-3D finite element model of tool-part was established,and the cutting processes of new coated high-speed steel tools with MoS2 ,WS2 and Sb2 O3 were simulated. By contrast with the cutting test,the accuracies of the variations of cutting force and cutting temperature in different feed rate or back cutting depth were verified. Simulation results show that the new type of coating can reduce the cutting heat and cut-ting force of tools and extend tool life in dry cutting at middle-low speed effectively.

  9. Microscopic Invasions, Prognoses, and Recurrence Patterns of Stage I Adenocarcinomas Manifesting as Part-Solid Ground-Glass Nodules: Comparison With Adenocarcinomas Appearing as Solid Nodules After Matching Their Solid Parts' Size.

    Hwang, Eui Jin; Park, Chang Min; Kim, Young Tae; Kim, Hyungjin; Goo, Jin Mo


    The purpose of the present study was to compare the frequency of microscopic invasions, disease-free-survival (DFS), and the frequency and pattern of disease recurrence between stage I pulmonary adenocarcinomas appearing as solid nodules and those appearing as part-solid ground-glass nodules (GGNs) after matching their solid parts' size (D(solid)) and patients' age. Among 501 patients who underwent curative surgery for stage I pulmonary adenocarcinomas between 2003 and 2011, 172 patients (86 with solid nodules [M: F = 36: 50; mean age, 62.8 years] and 86 with part-solid GGNs [M:F = 30:56; mean age, 63.0 years]) matched for D(solid) and patients' age were included. DFS, frequency of microscopic invasions, recurrence, and recurrence pattern were compared between the two groups. No significant difference was observed in the frequency of microscopic invasions between the two groups (visceral pleural invasion, 30.23% vs. 29.07%, P = 0.867; lymphatic invasion, 5.81% vs. 3.49%, P = 0.720; vascular invasion, 1.16% vs. 0%, P = 1.000; solid nodules vs. part-slid GGNs, respectively) and DFS (estimated 5-year DFS, 83.6% vs. 81.9%, P = 0.744; solid nodules vs. part-slid GGNs, respectively). As for recurrence and recurrence pattern, there were no significant differences between the solid nodule group (14/86), and part-solid GGN group (12/86) (P = 0.670). Lung parenchymal nodules were the most frequent pattern of disease recurrence in both groups, followed by pleural seeding. In conclusion, after matching D(solid) and patients' age, there was no significant difference in the frequency of microscopic invasions, DFS, and the frequency and pattern of recurrence between stage I pulmonary adenocarcinomas appearing as solid nodules and part-solid GGNs.

  10. Lubrication in tablet formulations.

    Wang, Jennifer; Wen, Hong; Desai, Divyakant


    Theoretical aspects and practical considerations of lubrication in tablet compression are reviewed in this paper. Properties of the materials that are often used as lubricants, such as magnesium stearate, in tablet dosage form are summarized. The manufacturing process factors that may affect tablet lubrication are discussed. As important as the lubricants in tablet formulations are, their presence can cause some changes to the tablet physical and chemical properties. Furthermore, a detailed review is provided on the methodologies used to characterize lubrication process during tablet compression with relevant process analytical technologies. Finally, the Quality-by-Design considerations for tablet formulation and process development in terms of lubrication are discussed.

  11. Mechanism of friction reduction and lubrication of nano-Al2O3-Fe3O4/FeS solid lubrication duplex layer%纳米Al2O3-Fe3O4/FeS固体润滑复合层减摩润滑机理

    胡春华; 杨春燕; 刘庆存; 孙志杰; 马世宁; 乔玉林


    FeS solid lubrication duplex layer was prepared on the surface of 45 steel by ion nitrocarburizing-ion sulphurizing process.Then the nano-Al2O3 and nano-Fe3O4 particles were set into the holes in micron and nano scale of the duplex layer by using vacuum dipping process to prepare the nano-Al2O3-Fe2O4/FeS solid lubrication duplex layer.Friction and wear performances of the nano-Al2O3-Fe3O4/FeS solid lubrication duplex layer were investigated and the excellent performances are obtained under 10 N-60 N loads.The results show that the chemical reaction films are formed,which possess the functions of solid lubrication and cumbering the direct contact of the metals between the friction surfaces.Moreover,the nano-Al2O3 and nano-Fe3O4 particles in the nano-Al2O3-Fe3O4/FeS solid lubrication duplex layer play the “micron and nano ball bearing” function,which can transform the “sliding friction” into the “rolling friction” in micro scale,and furthermore,the nano particles are beforehand set into the holes of the duplex layer and are difficult to run off in the friction process,which prolong their “micron and nano ball bearing” function,so the friction factor (under load 60N) and volume loss of the nano-Al2O3-Fe3O4/FeS solid lubrication duplex layer are 7.2% and 50% lower than those of the FeS solid lubrication duplex layer lubricated by applying nano-Al2O3/nano-Fe3O4 additive,respectively.%采用离子氮碳共渗与离子渗硫复合处理技术在45钢表面形成FeS固体润滑复合层,然后采用真空浸渍方法将纳米Al2O3和Fe3O4颗粒置入复合层的微纳孔隙中,制备成纳米Al2O3-Fe3O4/FeS固体润滑复合层.在10 ~60 N的载荷下,纳米Al2O3-Fe3O4/FeS固体润滑复合层表现出优良的减摩与耐磨性能.这是因为,一方面磨损表面生成的化学反应膜,起到了固体润滑和阻碍摩擦表面间金属直接接触的作用;另一方面在摩擦过程中,纳米Al2O3-Fe3O4/FeS固体润滑复合层中的纳米Al2O

  12. A dynamic rheological model for thin-film lubrication

    Zhang Xiang-Jun; Huang Ying; Guo Yan-Bao; Tian Yu; Meng Yong-Gang


    In this study,the effects of the non-Newtonian rheological properties of the lubricant in a thin-film lubrication regime between smooth surfaces were investigated.The thin-film lubrication regime typically appears in Stribeck curves with a clearly observable minimum coefficient of friction (COF) and a low-COF region,which is desired for its lower energy dissipation.A dynamic rheology of the lubricant from the hydrodynamic lubrication regime to the thin-film lubrication regime was proposed based on the convected Maxwell constitutive equation.This rheology model includes the increased relaxation time and the yield stress of the confined lubricant thin film,as well as their dependences on the lubricant film thickness.The Deborah number (De number) was adopted to describe the liquid-solid transition of the confined lubricant thin film under shearing.Then a series of Stribeck curves were calculated based on Tichy's extended lubrication equations with a perturbation of the De number.The results show that the minimum COF points in the Stribeck curve correspond to a critical De number of 1.0,indicating a liquid-to-solid transition of the confined lubricant film.Furthermore,the two proposed parameters in the dynamic rheological model,namely negative slipping length b (indicating the lubricant interfacial effect) and the characteristic relaxation time λ0,were found to determine the minimum COF and the width of the low-COF region,both of which were required to optimize the shape of the Stribeck curve.The developed dynamic rheological model interprets the correlation between the rheological and interfacial properties of lubricant and its lubrication behavior in the thin-film regime.

  13. Adhesion of solid particles to gas bubbles. Part 2: Experimental

    Omota, Florin; Dimian, Alexandre C.; Bliek, Alfred


    In slurry bubble columns, the adhesion of solid catalyst particles to bubbles may significantly affect the G–L mass transfer and bubble size distribution. This feature may be exploited in design by modifying the hydrophilic or hydrophobic nature of the particles used. Previously we have proposed a g

  14. Solid Lubricated Rolling Element Bearings


    Metal, X is the chalco -en atom and x is the relative amount of the intercalated species. In the alkali intercalated species, 0< x <l and the alkali...stabilize them at the stoichiometric 1.X2 coi.inositlon. Also, intercalation of alkali metal atoms into chalco . enides already oossessin:; the

  15. Graphite and Hybrid Nanomaterials as Lubricant Additives

    Zhenyu J. Zhang


    Full Text Available Lubricant additives, based on inorganic nanoparticles coated with organic outer layer, can reduce wear and increase load-carrying capacity of base oil remarkably, indicating the great potential of hybrid nanoparticles as anti-wear and extreme-pressure additives with excellent levels of performance. The organic part in the hybrid materials improves their flexibility and stability, while the inorganic part is responsible for hardness. The relationship between the design parameters of the organic coatings, such as molecular architecture and the lubrication performance, however, remains to be fully elucidated. A survey of current understanding of hybrid nanoparticles as lubricant additives is presented in this review.

  16. Metal forming and lubrication

    Bay, Niels


    Lubrication is essential in most metal forming processes. The lubricant film has two basic functions, [1]: i. to separate the work piece and tool surfaces and ii. to cool the workpiece and the tool. Separation of the two surfaces implies lower friction facilitating deformation and lowering the tool...... deformation step to avoid overheating and breakdown of the lubricant....

  17. Dry lubricant films for aluminum forming.

    Wei, J.; Erdemir, A.; Fenske, G. R.


    During metal forming process, lubricants are crucial to prevent direct contact, adhesion, transfer and scuffing of workpiece materials and tools. Boric acid films can be firmly adhered to the clean aluminum surfaces by spraying their methanol solutions and provide extremely low friction coefficient (about 0.04). The cohesion strengths of the bonded films vary with the types of aluminum alloys (6061, 6111 and 5754). The sheet metal forming tests indicate that boric acid films and the combined films of boric acid and mineral oil can create larger strains than the commercial liquid and solid lubricants, showing that they possess excellent lubricities for aluminum forming. SEM analyses indicate that boric acid dry films separate the workpiece and die materials, and prevent their direct contact and preserve their surface qualities. Since boric acid is non-toxic and easily removed by water, it can be expected that boric acid films are environmentally friendly, cost effective and very efficient lubricants for sheet aluminum cold forming.

  18. Limits of Lubrication in

    Olsson, David Dam

    of different lubricants indicate that both commercial and prototype, environmental friendly lubricants do not perform as well as hazardous lubricants such as chlorinated paraffin oils. Dry-in lubricants and polymer-coated sheets have been found to perform very poorly in punching and blanking due to shearing......-models corresponds well to experimental results in terms of lubricant film breakdown and subsequently pick-up development. Punching and blanking have been investigated regarding tribological conditions in case of using stainless steel workpiece materials. However, this has called for development of a new test method...

  19. Metallurgical Aspects of Self-lubricating Composites Containing Graphite and MoS2

    Furlan, Kaline Pagnan; da Costa Gonçalves, Priscila; Consoni, Deise Rebelo; Dias, Matheus Vinícius Gouvêa; de Lima, Gabriel Araújo; de Mello, José Daniel Biasoli; Klein, Aloisio Nelmo


    The performance of dry self-lubricating bulk materials is directly related to microstructural aspects such as solid lubricant chemical composition and distribution. In this paper, dry powder mixtures were prepared from iron powder and 9-16.5 vol.% of solid lubricants (graphite and MoS2), both combined and isolated. The results showed that interactions and reactions occurred during processing, either between the solid lubricants or between the lubricants and the matrix, generating carbides and sulfides. On account of that, the lubricant distribution in the microstructure is greatly altered, and the microhardness, friction coefficient and wear rate are increased. The best results were achieved by adequate powder particle size, solid lubricant content and sintering temperature control. In the composite containing 9%MoS2 + 2.5%C, values of friction coefficient and wear rate lower than 0.08 and 8 × 10-6 mm3 N-1 m-1 were reached.

  20. Thermocapillary motion on lubricant-impregnated surfaces

    Bjelobrk, Nada; Girard, Henri-Louis; Bengaluru Subramanyam, Srinivas; Kwon, Hyuk-Min; Quéré, David; Varanasi, Kripa K.


    We show that thermocapillary-induced droplet motion is markedly enhanced when using lubricant-impregnated surfaces as compared to solid substrates. These surfaces provide weak pinning, which makes them ideal for droplet transportation and specifically for water transportation. Using a lubricant with viscosity comparable to that of water and temperature gradients as low as 2 K/mm, we observe that drops can propel at 6.5 mm/s, that is, at least 5 times quicker than reported on conventional substrates. Also in contrast with solids, the liquid nature of the different interfaces makes it possible to predict quantitatively the thermocapillary Marangoni force (and velocity) responsible for the propulsion.

  1. Global Evolution of Solid Matter in Turbulent Protoplanetry Disks. Part 1; Aerodynamics of Solid Particles

    Stepinski, T. F.; Valageas, P.


    The problem of planetary system formation and its subsequent character can only be addressed by studying the global evolution of solid material entrained in gaseous protoplanetary disks. We start to investigate this problem by considering the space-time development of aerodynamic forces that cause solid particles to decouple from the gas. The aim of this work is to demonstrate that only the smallest particles are attached to the gas, or that the radial distribution of the solid matter has no momentary relation to the radial distribution of the gas. We present the illustrative example wherein a gaseous disk of 0.245 solar mass and angular momentum of 5.6 x 10(exp 52) g/sq cm/s is allowed to evolve due to turbulent viscosity characterized by either alpha = 10(exp -2) or alpha = 10(exp -3). The motion of solid particles suspended in a viscously evolving gaseous disk is calculated numerically for particles of different sizes. In addition we calculate the global evolution of single-sized, noncoagulating particles. We find that particles smaller than 0.1 cm move with the gas; larger particles have significant radial velocities relative to the gas. Particles larger than 0.1 cm but smaller than 10(exp 3) cm have inward radial velocities much larger than the gas, whereas particles larger than 10(exp 4) cm have inward velocities much smaller than the gas. A significant difference in the form of the radial distribution of solids and the gas develops with time. It is the radial distribution of solids, rather than the gas, that determines the character of an emerging planetary system.

  2. Determining the Thermal Properties of Space Lubricants

    Maldonado, Christina M.


    Many mechanisms used in spacecrafts, such as satellites or the space shuttle, employ ball bearings or gears that need to be lubricated. Normally this is not a problem, but in outer space the regular lubricants that are used on Earth will not function properly. Regular lubricants will quickly vaporize in the near vacuum of space. A unique liquid called a perfluoropolyalkylether (PFPE) has an extremely low vapor pressure, around l0(exp -10) torr at 20 C, and has been used in numerous satellites and is currently used in the space shuttle. Many people refer to the PFPEs as "liquid Teflon". PFPE lubricants however, have a number of problems with them. Lubricants need many soluble additives, especially boundary and anti-wear additives, in them to function properly. All the regular known boundary additives are insoluble in PFPEs and so PFPEs lubricate poorly under highly loaded conditions leading to many malfunctioning ball bearings and gears. JAXA, the Japanese Space Agency, is designing and building a centrifuge rotor to be installed in the International Space Station. The centrifuge rotor is part of a biology lab module. They have selected a PFPE lubricant to lubricate the rotor s ball bearings and NASA bearing experts feel this is not a wise choice. An assessment of the centrifuge rotor design is being conducted by NASA and part of the assessment entails knowing the physical and thermal properties of the PFPE lubricant. One important property, the thermal diffusivity, is not known. An experimental apparatus was set up in order to measure the thermal diffusivity of the PFPE. The apparatus consists of a constant temperature heat source, cylindrical Pyrex glassware, a thermal couple and digital thermometer. The apparatus was tested and calibrated using water since the thermal diffusivity of water is known.

  3. Biofluid lubrication for artificial joints

    Pendleton, Alice Mae

    This research investigated biofluid lubrication related to artificial joints using tribological and rheological approaches. Biofluids studied here represent two categories of fluids, base fluids and nanostructured biofluids. Base fluids were studied through comparison of synthetic fluids (simulated body fluid and hyaluronic acid) as well as natural biofluids (from dogs, horses, and humans) in terms of viscosity and fluid shear stress. The nano-structured biofluids were formed using molecules having well-defined shapes. Understanding nano-structured biofluids leads to new ways of design and synthesis of biofluids that are beneficial for artificial joint performance. Experimental approaches were utilized in the present research. This includes basic analysis of biofluids' property, such as viscosity, fluid shear stress, and shear rate using rheological experiments. Tribological investigation and surface characterization were conducted in order to understand effects of molecular and nanostructures on fluid lubrication. Workpiece surface structure and wear mechanisms were investigated using a scanning electron microscope and a transmission electron microscope. The surface topography was examined using a profilometer. The results demonstrated that with the adding of solid additives, such as crown ether or fullerene acted as rough as the other solids in the 3-body wear systems. In addition, the fullerene supplied low friction and low wear, which designates the lubrication purpose of this particular particle system. This dissertation is constructed of six chapters. The first chapter is an introduction to body fluids, as mentioned earlier. After Chapter II, it examines the motivation and approach of the present research, Chapter III discusses the experimental approaches, including materials, experimental setup, and conditions. In Chapter IV, lubrication properties of various fluids are discussed. The tribological properties and performance nanostructured biofluids are

  4. Dynamic spreading of nanofluids on solids. Part I: experimental.

    Kondiparty, Kirtiprakash; Nikolov, Alex D; Wasan, Darsh; Liu, Kuan-Liang


    Nanofluids have enhanced thermophysical properties compared to fluids without nanoparticles. Recent experiments have clearly shown that the presence of nanoparticles enhances the spreading of nanofluids. We report here the results of our experiments on the spreading of nanofluids comprising 5, 10, and 20 vol % silica suspensions of 19 nm particles displacing a sessile drop placed on a glass surface. The contact line position is observed from both the top and side views simultaneously using an advanced optical technique. It is found that the nanofluid spreads, forming a thin nanofluid film between the oil drop and the solid surface, which is seen as a bright inner contact line distinct from the conventional three-phase outer contact line. For the first time, the rate of the nanofluidic film spreading is experimentally observed as a function of the nanoparticle concentration and the oil drop volume. The speed of the inner contact line is seen to increase with an increase in the nanoparticle concentration and decrease with a decrease in the drop volume, that is, with an increase in the capillary pressure. Interestingly, the formation of the inner contact line is not seen in fluids without nanoparticles.

  5. Lubrication of Nitinol 60

    Pepper, Stephen V.; DellaCorte, Christopher; Glennon, Glenn


    The mechanical properties of Nitinol 60, 60 wt% Ni, 40 wt% Ti (55 at.% Ni, 45 at.% Ti) are sufficiently attractive to warrant its consideration as a lubricated triboelement. Triboelements are always run lubricated. The ability to lubricate Nitinol 60 by the oils usually used on spacecraft mechanisms--Pennzane 2001A, Krytox 143AC and Castrol 815Z--was experimentally determined. These oils were run in the boundary lubrication regime for Nitinol 60 balls running against Nitinol 60 counterfaces in the vacuum spiral orbit tribometer. Test results consisting of the coefficient of friction versus time (friction traces) and relative degradation rates of the oils are presented. Contrary to the inability to successfully lubricate other metal alloys with high titanium content, it was found that Nitinol 60 is able to be lubricated by these oils. Overall, the results presented here indicate that Nitinol 60 is a credible candidate material for bearing applications.

  6. Fiscal 1998 international research cooperation project. Research report on development of ultra-solid lubricant with cluster diamond; 1998 nendo kokusai kenkyu kyoroku jigyo seika hokokusho. Kurasuta diamond wo riyoshita kotai junkatsu fukugo zairyo no kaihatsu



    Study was made on cluster diamond-dispersed composite materials to develop advanced ultra-solid lubricant. As for processing technology of such composite materials, study was made on the uniform mixing condition of cluster diamond and Cu or Cu-Sn alloy by mechanical milling. The fabricated composite powder was caked by vacuum hot compressive formation technique. The production process of composite materials composed of cluster diamond and TiO{sub 2} was also developed by using sol-gel technique. As for formation of a functional layer and development of micro- formation technology, the prototype forming equipment using radial extrusion process and the mould were designed and prepared. In the preliminary experiment only for matrix, study was made on working limit, material flow, fine recrystallization and working condition during working. The friction test result showed the antifrictional property of the cluster diamond-dispersed composite materials using Cu, Cu-Sn, Al, Al-Si as matrix. (NEDO)

  7. 钛合金表面激光熔覆h-BN固体润滑涂层%Solid Self-lubricating Coatings on TC4 Titanium Alloy by Laser Cladding with h-BN

    王培; 叶源盛


    目的:优化钛合金激光熔覆固体润滑涂层的熔覆工艺参数,提高钛合金表面耐磨性能。方法采用Nd:YAG激光器,分别在高功率和低功率条件下,在TC4钛合金表面制备h-BN固体自润滑涂层。观察分析熔覆陶瓷层的宏观形貌、物相组成、显微组织和硬度,采用摩擦磨损试验仪对熔覆层的摩擦学性能进行研究。结果低激光功率下,熔覆材料上浮流失严重,熔覆层的相成分主要是TiN,TiB,TiB2等硬质相,硬度较高,存在裂纹。高激光功率下,基材的熔化稀释较好地抑制了润滑相h-BN的上浮,减少了溅射损失,发生了包晶反应,生成了单质金属Ti,熔覆层硬度低,但摩擦磨损试验表明,涂层中润滑相h-BN含量的增加使得形成了更好的润滑膜,降低了摩擦系数。结论在输出电流400 A,脉宽5 ms,频率12 Hz,扫描速度120 mm/min,搭接率50%~60%的条件下进行激光熔覆,所得熔覆层的表面状态平整,耐摩擦性能最好。%ABSTRACT:Objective To optimize the process parameters for laser cladding of solid self-lubricating coatings on titanium alloy, and improve the surface wear resistance of titanium alloy. Methods Using the Nd: YAG laser, h-BN ( hexagonal boron nitride) solid self-lubricating coatings were prepared on the surface of TC4 titanium alloy under conditions of high power and low power, re-spectively. The macro morphology, layer phase composition, microstructure, hardness and wear resistance of the ceramic layer were analyzed, and the tribological property of the ceramic layer was studied using a friction and wear tester. Results At low laser power, there was severe floating loss of cladding material, and the phase composition of the cladding layer was mainly composed of TiN, TiB, TiB2 and other hard phase components, the hardness was relatively high, with the presence of cracks. At high laser power, melting of the substrate inhibited the floating of the lubricating phase h-BN, reducing the

  8. Assessment of Introital Lubrication.

    Dawson, Samantha J; Sawatsky, Megan L; Lalumière, Martin L


    Vaginal vasocongestion and lubrication serve to prepare the vaginal lumen for sexual activity. Lubrication is important for sexual functioning and difficulties with lubrication are one of the most commonly reported symptoms of sexual dysfunction. Few studies have empirically examined how vasocongestion and lubrication relate to one another and there are currently no well-established measures of lubrication. In this study, we designed and tested a simple method to assess lubrication at the vaginal introitus in 19 healthy women, using litmus test strips. We examined the relationship between lubrication and vaginal vasocongestion (measured with a photoplethysmograph) when elicited by audiovisual sexual stimuli (male-female sexual interactions). Lubrication was elicited by the sexual stimuli and was strongly correlated with reports of sexual arousal. Unexpectedly, lubrication was not correlated with vasocongestion, even though the latter was also elicited by the sexual stimuli. We discuss the implications of these findings for informing our understanding of the female sexual response and the potential clinical and scientific utility of this new measure.

  9. Fundamentals of fluid lubrication

    Hamrock, Bernard J.


    The aim is to coordinate the topics of design, engineering dynamics, and fluid dynamics in order to aid researchers in the area of fluid film lubrication. The lubrication principles that are covered can serve as a basis for the engineering design of machine elements. The fundamentals of fluid film lubrication are presented clearly so that students that use the book will have confidence in their ability to apply these principles to a wide range of lubrication situations. Some guidance on applying these fundamentals to the solution of engineering problems is also provided.

  10. Tribochemical synthesis of nano-lubricant films from adsorbed molecules at sliding solid interface: Tribo-polymers from α-pinene, pinane, and n-decane

    He, Xin; Barthel, Anthony J.; Kim, Seong H.


    The mechanochemical reactions of adsorbed molecules at sliding interfaces were studied for α-pinene (C10H16), pinane (C10H18), and n-decane (C10H22) on a stainless steel substrate surface. During vapor phase lubrication, molecules adsorbed at the sliding interface could be activated by mechanical shear. Under the equilibrium adsorption condition of these molecules, the friction coefficient of sliding steel surfaces was about 0.2 and a polymeric film was tribochemically produced. The synthesis yield of α-pinene tribo-polymers was about twice as much as pinane tribo-polymers. In contrast to these strained bicyclic hydrocarbons, n-decane showed much weaker activity for tribo-polymerization at the same mechanical shear condition. These results suggested that the mechanical shear at tribological interfaces could induce the opening of the strained ring structure of α-pinene and pinane, which leads to polymerization of adsorbed molecules at the sliding track. On a stainless steel surface, such polymerization reactions of adsorbed molecules do not occur under typical surface reaction conditions. The mechanical properties and boundary lubrication efficiency of the produced tribo-polymer films are discussed.

  11. Squeezing molecularly thin alkane lubrication films: Layering transistions and wear

    Sivebæk, Ion Marius; Samoilov, V. N.; Persson, B. N. J.


    The properties of alkane lubricants confined between two approaching solids are investigated by a model that accounts for the curvature and the elastic properties of the solid surfaces. We consider linear alkane molecules of different chain lengths, C(3)H(8); C(4)H(10); C(8)H(18); C(9)H(20); C(10)H......(22); C(12)H(26), and C(14)H(30) confined between smooth gold surfaces. We observe well-defined molecular layers develop in the lubricant film when the width of the film is of the order of a few atomic diameters. An external squeezing-pressure induces discontinuous changes in the number n of lubricant...

  12. Sporting Good Lubricants


    Sun Coast Chemicals was originally contracted by Lockheed Martin Space Operations to formulate a spray lubricant free of environmental drawbacks for the Mobile Launch Platform used to haul the Space Shuttle from the Kennedy Space Center Vehicle Assembly Building to a launch pad. From this work, Sun Coast introduced Train Track Lubricant, Penetrating Spray Lube, and Biodegradable Hydraulic Fluid. Based on the original lubricant work, two more products have also been introduced. First, the X-1R Super Gun Cleaner and Lubricant protects guns from rust and corrosion caused by environmental conditions. Second, the X-1R Tackle Pack, endorsed by both fresh and saltwater guides and certain reel manufacturers, penetrates, cleans, reduces friction, lubricates, and provides extra protection against rust and corrosion.

  13. Finite element treatment of soft elastohydrodynamic lubrication problems in the finite deformation regime

    Stupkiewicz, Stanisław


    Soft elastohydrodynamic lubrication (EHL) problem is studied for a reciprocating elastomeric seal with full account of finite configuration changes. The fluid part is described by the Reynolds equation which is formulated on the deformed boundary of the seal treated as a hyperelastic body. The paper is concerned with the finite element (FE) treatment of this soft EHL problem. Displacement-based FE discretization is applied for the solid part. The Reynolds equation is discretized using the FE method or, alternatively, the discontinuous Galerkin method, both employing higher-order interpolation of pressure. The performance of both methods is assessed by studying convergence and stability of the solution for a benchmark problem of an O-ring seal. It is shown that the solution may exhibit spurious oscillations which occur in severe lubrication conditions. Mesh refinement results in reduction of these oscillations, while increasing the pressure interpolation order or application of the discontinuous Galerkin method does not help significantly.

  14. Solid state chemistry of nitrogen oxides--part II: surface consumption of NO2.

    Ioppolo, S; Fedoseev, G; Minissale, M; Congiu, E; Dulieu, F; Linnartz, H


    Nitrogen oxides are considered to be important astrochemical precursors of complex species and prebiotics. However, apart from the hydrogenation of solid NO that leads to the surface formation of hydroxylamine, little is known about the full solid state reaction network involving both nitrogen and oxygen. Our study is divided into two papers, hereby called Part I and Part II. In the accompanying paper, we investigate the surface reactions NO + O/O2/O3 and NO + N with a focus on the formation of NO2 ice. Here, we complement this study by measurements of the surface destruction of solid NO2, e.g., NO2 + H/O/N. Experiments are performed in two separate ultra-high vacuum setups and therefore under different experimental conditions to better constrain the experimental results. Surface reaction products are monitored by means of Fourier Transform Reflection Absorption Infrared Spectroscopy (FT-RAIRS) and Temperature Programmed Desorption (TPD) techniques using mass spectrometry. The surface destruction of solid NO2 leads to the formation of a series of nitrogen oxides such as NO, N2O, N2O3, and N2O4 as well as HNO, NH2OH, and H2O. When NO2 is mixed with an interstellar more relevant apolar (i.e., CO) ice, solid CO2 and HCOOH are also formed due to interactions between different reaction routes. The astrophysical implications of the full nitrogen and oxygen reaction network derived from Parts I and II are discussed.

  15. Lubrication of chocolate during oral processing.

    Rodrigues, S A; Selway, N; Morgenstern, M P; Motoi, L; Stokes, J R; James, B J


    The structure of chocolate is drastically transformed during oral processing from a composite solid to an oil/water fluid emulsion. Using two commercial dark chocolates varying in cocoa solids content, this study develops a method to identify the factors that govern lubrication in molten chocolate and saliva's contribution to lubrication following oral processing. In addition to chocolate and its individual components, simulated boluses (molten chocolate and phosphate buffered saline), in vitro boluses (molten chocolate and whole human saliva) and ex vivo boluses (chocolate expectorated after chewing till the point of swallow) were tested. The results reveal that the lubrication of molten chocolate is strongly influenced by the presence of solid sugar particles and cocoa solids. The entrainment of particles into the contact zone between the interacting surfaces reduces friction such that the maximum friction coefficient measured for chocolate boluses is much lower than those for single-phase Newtonian fluids. The addition of whole human saliva or a substitute aqueous phase (PBS) to molten chocolate dissolves sugar and decreases the viscosity of molten chocolate so that thinner films are achieved. However, saliva is more lubricating than PBS, which results in lower friction coefficients for chocolate-saliva mixtures when compared to chocolate-PBS mixtures. A comparison of ex vivo and in vitro boluses also suggests that the quantity of saliva added and uniformity of mixing during oral processing affect bolus structure, which leads to differences in measured friction. It is hypothesized that inhomogeneous mixing in the mouth introduces large air bubbles and regions of non-emulsified fat into the ex vivo boluses, which enhance wetting and lubrication.

  16. Effects of automated external lubrication on tablet properties and the stability of eprazinone hydrochloride.

    Yamamura, Takahiro; Ohta, Tomoaki; Taira, Toshinari; Ogawa, Yutaka; Sakai, Yasuyuki; Moribe, Kunikazu; Yamamoto, Keiji


    We investigated the advantages of an external lubrication technique for tableting. A newly developed external lubricating system was applied to tableting in a rotary tablet press using magnesium stearate. The resulting tablets were compared with tablets produced by the conventional internal lubrication method, in which lubricant is blended before tableting. As a model API, we chose eprazinone hydrochloride, because it is easily hydrolyzed by alkaline lubricant. The amount of lubricant required to prevent sticking with external lubrication was only 1/13th of that required with internal lubrication. External lubrication increased tablet crushing strength by 40%, without prolonging tablet disintegration time, and improved the residual ratio of eprazinone hydrochloride in tablets stored under stress conditions for 4 weeks by 10%. The distribution of lubricant on the surface of externally lubricated tablets was observed by scanning electron microscopy after the preparation by focused ion beam milling. The lubricant had formed a layer on the tablet surface. At the central part of the tablet surface, this layer was much thinner than at the edges, and remained extremely thin even when there was excess magnesium stearate. This is the first report to describe the distribution of lubricant on the surface of externally lubricated tablets.

  17. Tribology of the lubricant quantized sliding state.

    Castelli, Ivano Eligio; Capozza, Rosario; Vanossi, Andrea; Santoro, Giuseppe E; Manini, Nicola; Tosatti, Erio


    In the framework of Langevin dynamics, we demonstrate clear evidence of the peculiar quantized sliding state, previously found in a simple one-dimensional boundary lubricated model [A. Vanossi et al., Phys. Rev. Lett. 97, 056101 (2006)], for a substantially less idealized two-dimensional description of a confined multilayer solid lubricant under shear. This dynamical state, marked by a nontrivial "quantized" ratio of the averaged lubricant center-of-mass velocity to the externally imposed sliding speed, is recovered, and shown to be robust against the effects of thermal fluctuations, quenched disorder in the confining substrates, and over a wide range of loading forces. The lubricant softness, setting the width of the propagating solitonic structures, is found to play a major role in promoting in-registry commensurate regions beneficial to this quantized sliding. By evaluating the force instantaneously exerted on the top plate, we find that this quantized sliding represents a dynamical "pinned" state, characterized by significantly low values of the kinetic friction. While the quantized sliding occurs due to solitons being driven gently, the transition to ordinary unpinned sliding regimes can involve lubricant melting due to large shear-induced Joule heating, for example at large speed.

  18. Low-cost solid FeS lubricant as a possible alternative to MoS2 for producing Fe-based friction materials

    Peng, Tao; Yan, Qing-zhi; Zhang, Yan; Shi, Xiao-jiao; Ba, Ming-yang


    Three reaction systems of MoS2-Fe, FeS-Fe, and FeS-Fe-Mo were designed to investigate the use of FeS as an alternative to MoS2 for producing Fe-based friction materials. Samples were prepared by powder metallurgy, and their phase compositions, microstructures, mechanical properties, and friction performance were characterized. The results showed that MoS2 reacts with the matrix to produce iron-sulfides and Mo when sintered at 1050°C. Iron-sulfides produced in the MoS2-Fe system were distributed uniformly and continuously in the matrix, leading to optimal mechanical properties and the lowest coefficient of friction among the systems studied. The lubricity observed was hypothesized to originate from the iron-sulfides produced. The FeS-Fe-Mo system showed a phase composition, porosity, and density similar to those of the MoS2-Fe system, but an uneven distribution of iron-sulfides and Mo in this system resulted in less-optimal mechanical properties. Finally, the FeS-Fe system showed the poorest mechanical properties among the systems studied because of the lack of Mo reinforcement. In friction tests, the formation of a sulfide layer contributed to a decrease in coefficient of friction (COF) in all of the samples.

  19. Lubricant for cold plastic metal working

    Postolov, Yu.M.; Larina, N.F.; Osadchuk, Ye.S.; Proskuryakov, V.A.; Syroyezhko, A.M.; Vikhorev, A.A.; Yakovlev, V.I.


    A lubricant is proposed for cold plastic metal working based on fatty acids from the process of pyrolysis of castor oil (ZhKPM) with increased screening properties and which improve the quality of PV of finished parts. The lubricant contains (percent): cyclohexanol 0.5-60, levulinic and/or ketoenanthic acid 0.5-20, ZhKPM up to 100; the content of ketoenanthic acid in mixture with levulinic acid is 20-50 percent. Tests of the number of proposed lubricants were conducted for cold stampling of parts from a metal strip on a 10 ton mechanical press. Tool stability (number of pieces until adhesion) was 1200-1400, purity class Pv-7. In tests under a similar condition of vegetable oil, ZhKPM and a mixture of ZhKPM with esters (nonlubricant) tool stability was 1100, and the purity class Pv-6.

  20. Origins of hydration lubrication.

    Ma, Liran; Gaisinskaya-Kipnis, Anastasia; Kampf, Nir; Klein, Jacob


    Why is friction in healthy hips and knees so low? Hydration lubrication, according to which hydration shells surrounding charges act as lubricating elements in boundary layers (including those coating cartilage in joints), has been invoked to account for the extremely low sliding friction between surfaces in aqueous media, but not well understood. Here we report the direct determination of energy dissipation within such sheared hydration shells. By trapping hydrated ions in a 0.4-1 nm gap between atomically smooth charged surfaces as they slide past each other, we are able to separate the dissipation modes of the friction and, in particular, identify the viscous losses in the subnanometre hydration shells. Our results shed light on the origins of hydration lubrication, with potential implications both for aqueous boundary lubricants and for biolubrication.

  1. Lubrication of Articular Cartilage.

    Jahn, Sabrina; Seror, Jasmine; Klein, Jacob


    The major synovial joints such as hips and knees are uniquely efficient tribological systems, able to articulate over a wide range of shear rates with a friction coefficient between the sliding cartilage surfaces as low as 0.001 up to pressures of more than 100 atm. No human-made material can match this. The means by which such surfaces maintain their very low friction has been intensively studied for decades and has been attributed to fluid-film and boundary lubrication. Here, we focus especially on the latter: the reduction of friction by molecular layers at the sliding cartilage surfaces. In particular, we discuss such lubrication in the light of very recent advances in our understanding of boundary effects in aqueous media based on the paradigms of hydration lubrication and of the synergism between different molecular components of the synovial joints (namely hyaluronan, lubricin, and phospholipids) in enabling this lubrication.

  2. Fuels and Lubricants Facility

    Federal Laboratory Consortium — Modern naval aircraft and turbine-powered craft require reliable and high-quality fuels and lubricants to satisfy the demands imposed upon them for top performance...

  3. Liquid lubrication in space

    Zaretsky, Erwin V.


    The requirement for long-term, reliable operation of aerospace mechanisms has, with a few exceptions, pushed the state of the art in tribology. Space mission life requirements in the early 1960s were generally 6 months to a year. The proposed U.S. space station schedule to be launched in the 1990s must be continuously usable for 10 to 20 years. Liquid lubrication systems are generally used for mission life requirements longer than a year. Although most spacecraft or satellites have reached their required lifetimes without a lubrication-related failure, the application of liquid lubricants in the space environment presents unique challenges. The state of the art of liquid lubrication in space as well as the problems and their solutions are reviewed.

  4. Lubricants for HFC-134a Compatible Rotary Compressors

    Takaichi, Kenji; Sakai, Hisakazu

    In replacing CFC-12 with HFC-134a for refrigerator compressors, the compatibility with lubricating oil, and lubrication in general, are of major concern. HFC-134a dose not have adequate solubility with current lubricating oils because of its molecular structure. Current oils also do not provide enough lubricating action when using HFC-134a. A new oil and new materials have to be utilized in order to use HFC-134a. Developing a new lubricating oil involved numerous tests of different combinations of many polyolester synthetic oils and additives. One of the pre-evaluated methods was pursued via sealed tube tests. Lubricated parts were selected by studies involving a plane-on-roller type of wear test machine and by analyzing the traces of acid material commonly created during the lubricating action. The matrices of new lubricating oils and new lubricated materials were estimated based on durability tests conducted on compressors and refrigerators. Results showed that polyolester synthetic oils having a low total acid value and including certain quantities of additives did not break down into a tar-like substance and they did not produce composite particles in the operating compressors and refrigerators. The study also found that ceramics and anti-corrosion alloy steel possessed good adrasion-reducing qualities. Based on our evaluation, we will implement compressor reliability tests and apply HFC-134a to rotary compressors for refrigerators.

  5. Piezoviscous effects in nonconformal contacts lubricated hydrodynamically

    Jeng, Yeau-Ren; Hamrock, Bernard J.; Brewe, David E.


    The analysis is concerned with the piezoviscous-rigid regime of lubrication for the general case of elliptical contacts. In this regime several formulas of the lubricant film thickness have been proposed by Hamrock and Dowson, by Dowson et al., and more recently by Houpert. However, either they do not include the load parameter W, which has a strong effect on film thickness, or they overestimate the film thickness by using the Barus formula for pressure-viscosity characteristics. The Roelands formula was used for the pressure-viscosity relationship. The effects of the dimensionless load, speed, and materials parameters, the radius ratio, and the lubricant entrainment direction were investigated. The dimensionless load parameter was varied over a range of one order of magnitude. The dimensionless speed parameter was varied by 5.6 times the lowest value. Conditions corresponding to the use of solid materials of steel, bronze, and silicon nitride and lubricants of paraffinic and naphthenic mineral oil were considered in obtaining the exponent in the dimensionless materials parameter. The radius ratio was varied from 0.2 to 64 (a configuration approaching a line contact). Forty-one cases were used in obtaining a minimum film thickness formula. Contour plots indicate in detail the pressure developed between the contacting solids.

  6. Environmentally Acceptable Lubricants


    2008; Sada et al., 2008; and Sada et al., 2009). 2.4 WATER At least one company has developed a completely seawater-lubricated stern tube system...misalignment, and from contact with nets or fishing lines ( Sada et al., 2008 and Carter, 2009). The constant presence of seawater increases the potential for...other EALs; as a result, PAG EALs have received consideration as a stern tube lubricant ( Sada et al., 2008; Sada et al., 2009). The water solubility

  7. Lubricated viscous gravity currents

    Kowal, Katarzyna N.; Worster, M. Grae


    This is the author accepted manuscript. The final version is available via CUP at We present a theoretical and experimental study of viscous gravity currents lubricated by another viscous fluid from below. We use lubrication theory to model both layers as Newtonian fluids spreading under their own weight in two-dimensional and axisymmetric settings over a smooth rigid horizontal surfa...

  8. Methods to improve lubricity of fuels and lubricants

    Erdemir, Ali


    A method for providing lubricity in fuels and lubricants includes adding a boron compound to a fuel or lubricant to provide a boron-containing fuel or lubricant. The fuel or lubricant may contain a boron compound at a concentration between about 30 ppm and about 3,000 ppm and a sulfur concentration of less than about 500 ppm. A method of powering an engine to minimize wear, by burning a fuel containing boron compounds. The boron compounds include compound that provide boric acid and/or BO.sub.3 ions or monomers to the fuel or lubricant.

  9. Lubrication approximation for micro-particles moving along parallel walls

    Ekiel-Jezewska, M L; Blawzdziewicz, J; Feuillebois, F


    Lubrication expressions for the friction coefficients of a spherical particle moving in a fluid between and along two parallel solid walls are explicitly evaluated in the low-Reynolds-number regime. They are used to determine lubrication expression for the particle free motion under an ambient Poiseuille flow. The range of validity and the accuracy of the lubrication approximation is determined by comparing with the corresponding results of the accurate multipole procedure. The results are applicable for thin, wide and long microchannels, or quasi-two-dimensional systems.

  10. Power system with an integrated lubrication circuit

    Hoff, Brian D.; Akasam, Sivaprasad; Algrain, Marcelo C.; Johnson, Kris W.; Lane, William H.


    A power system includes an engine having a first lubrication circuit and at least one auxiliary power unit having a second lubrication circuit. The first lubrication circuit is in fluid communication with the second lubrication circuit.

  11. Lubrication System Failure Baseline Testing on an Aerospace Quality Gear Mesh

    Handschuh, Robert F.; Morales, Wilfredo


    Aerospace drive systems are required to survive a loss-of-lubrication test for qualification. In many cases emergency lubrication systems need to be designed and utilized to permit the drive system to pass this difficult requirement. The weight of emergency systems can adversely affect the mission capabilities of the aircraft. The possibility to reduce the emergency system weight through the use of mist lubrication will be described. Mist lubrication involves the delivery of a minute amount of an organic liquid as a vapor or fine mist in flowing compressed air to rubbing surfaces. At the rubbing surface, the vapor or mist reacts to form a solid lubricating film. The aim of this study was to establish a baseline for gear behavior under oil depleted conditions. A reactive vapor-mist lubrication method is described and proposed as a candidate emergency lubrication system.

  12. Steel silos for particulate solid materials : part 2 - membrane forces at filling and discharge.

    Petrovčič, Simon; Guggenberger, Werner; Brank, Boštjan


    In the paper, the expressions for membrane forces in an axisymmetric steel silo structure at filling and discharge with a particulate solid material are presented. Graphical plots of these expressions are given. They can be used for a quick and easy estimate of membrane forces distribution in all parts of a silo structure. The plots are valid for any silo geometry and for any material stored. The influence of silo geometry and stored material properties on the size and distribution of membran...

  13. Steel silos for particulate solid materials. Part 1, Actions at filling and discharge.

    Petrovčič, Simon; Guggenberger, Werner; Brank, Boštjan


    In the paper, the expressions for membrane forces in an axisymmetric steel silo structure at filling and discharge with a particulate solid material are presented. Graphical plots of these expressions are given. They can be used for a quick and easy estimate of membrane forces distribution in all parts of a silo structure. The plots are valid for any silo geometry and for any material stored. The influence of silo geometry and stored material properties on the size and distribution of membran...


    Ivan Gerdzhikov


    Full Text Available Aim: The aim of this study is to track the effectiveness of prosthetic treatment with post resection dentures with solid substitute part and their role in the restoration of damaged functions. Materials and methods: The study included 14 patients (9 men and 5 women with different size and location of defects in the upper jaw treated in the period 2010-2016 with post resection prostheses with a solid substitute part. The impressions were taken with irreversible hydrocolloid impression material. The prostheses were completed by heat-curing acrylic with low quantity residual monomer. The effectiveness of prosthetics was evaluated by the method of Mihaylov for both oral-nasal examination of the pressure with the device "Oronasopneumotest." For objectifying and assess the occlusal-articulation ratios was held computerized occlusal analysis with the system T-SCAN 8. Results: The results showed successful obturation and sealing of defects in all patients. It was found satisfactory recovery of the speaking function and normalization of occlusal-articulation ratios. Conclusion: The prosthetic treatment with post resection prostheses with a solid substitute part allows successful recovery of the lost speech and chewing functions, helping to restore self esteem and social rehabilitation of patients.

  15. Lubrication with Naturally Occurring Double Oxide Films


    are outlined in Table 7. These concepts are Lised on the proposition that a material car. be developed which will have adequwte properties to qualify...23999/6ST NTIS (1975) 9. Demorest, K.E., "Self Lubricating Gears and Other Rotating Parts", NASA Report N69-33484, 1969. 10. Mechlenburg, Karl R

  16. Programming and machining of complex parts based on CATIA solid modeling

    Zhu, Xiurong


    The complex parts of the use of CATIA solid modeling programming and simulation processing design, elaborated in the field of CNC machining, programming and the importance of processing technology. In parts of the design process, first make a deep analysis on the principle, and then the size of the design, the size of each chain, connected to each other. After the use of backstepping and a variety of methods to calculate the final size of the parts. In the selection of parts materials, careful study, repeated testing, the final choice of 6061 aluminum alloy. According to the actual situation of the processing site, it is necessary to make a comprehensive consideration of various factors in the machining process. The simulation process should be based on the actual processing, not only pay attention to shape. It can be used as reference for machining.

  17. Computational Chemistry and Lubrication

    Zehe, Michael J.


    Members of NASA Lewis Research Center's Tribology and Surface Science Branch are applying high-level computational chemistry techniques to the development of new lubrication systems for space applications and for future advanced aircraft engines. The next generation of gas turbine engines will require a liquid lubricant to function at temperatures in excess of 350 C in oxidizing environments. Conventional hydrocarbon-based lubricants are incapable of operating in these extreme environments, but a class of compounds known as the perfluoropolyether (PFAE) liquids (see the preceding illustration) shows promise for such applications. These commercially available products are already being used as lubricants in conditions where low vapor pressure and chemical stability are crucial, such as in satellite bearings and composite disk platters. At higher temperatures, however, these compounds undergo a decomposition process that is assisted (catalyzed) by metal and metal oxide bearing surfaces. This decomposition process severely limits the applicability of PFAE's at higher temperatures. A great deal of laboratory experimentation has revealed that the extent of fluid degradation depends on the chemical properties of the bearing surface materials. Lubrication engineers would like to understand the chemical breakdown mechanism to design a less vulnerable PFAE or to develop a chemical additive to block this degradation.

  18. On-line surveillance of lubricants in bearings by means of surface acoustic waves.

    Lindner, Gerhard; Schmitt, Martin; Schubert, Josephine; Krempel, Sandro; Faustmann, Hendrik


    The acoustic wave propagation in bearings filled with lubricants and driven by pulsed excitation of surface acoustic waves has been investigated with respect to the presence and the distribution of different lubricants. Experimental setups, which are based on the mode conversion between surface acoustic waves and compression waves at the interface between a solid substrate of the bearing and a lubricant are described. The results of preliminary measurements at linear friction bearings, rotation ball bearings and axial cylinder roller bearings are presented.

  19. Direct observation of drops on slippery lubricant-infused surfaces.

    Schellenberger, Frank; Xie, Jing; Encinas, Noemí; Hardy, Alexandre; Klapper, Markus; Papadopoulos, Periklis; Butt, Hans-Jürgen; Vollmer, Doris


    For a liquid droplet to slide down a solid planar surface, the surface usually has to be tilted above a critical angle of approximately 10°. By contrast, droplets of nearly any liquid "slip" on lubricant-infused textured surfaces - so termed slippery surfaces - when tilted by only a few degrees. The mechanism of how the lubricant alters the static and dynamic properties of the drop remains elusive because the drop-lubricant interface is hidden. Here, we image the shape of drops on lubricant-infused surfaces by laser scanning confocal microscopy. The contact angle of the drop-lubricant interface with the substrate exceeds 140°, although macroscopic contour images suggest angles as low as 60°. Confocal microscopy of moving drops reveals fundamentally different processes at the front and rear. Drops recede via discrete depinning events from surface protrusions at a defined receding contact angle, whereas the advancing contact angle is 180°. Drops slide easily, as the apparent contact angles with the substrate are high and the drop-lubricant interfacial tension is typically lower than the drop-air interfacial tension. Slippery surfaces resemble superhydrophobic surfaces with two main differences: drops on a slippery surface are surrounded by a wetting ridge of adjustable height and the air underneath the drop in the case of a superhydrophobic surface is replaced by lubricant in the case of a slippery surface.

  20. Tappet sleeve lubrication

    Kapp, G.E.


    In combination, this patent describes a non-ferrous body containing a lubricant distribution gallery, a sleeve of material diverse from that of the body and cast within the non-ferrous material thereof to form internally a bore for the reciprocating movement of a lubricated member, and an oil feed passage from the gallery through the non-ferrous material extension to the bore. The feed passage is wholly within the non-ferrous material and free of any intersection with the diverse material interface, whereby any leakage of pressure oil directly from the feed passage through the interface is avoided.

  1. Limits of Lubrication in

    Olsson, David Dam

    by strategic surfaces in comparison to normal stainless steel surfaces implying a larger extent of bi-axial stretching. Numerical simulations have been applied in order to evaluate limits of lubrication in the simulative strip reduction based on predictions of critical parameters appearing in terms...... of temperature and contact pressure. The numerical models have been calibrated regarding friction and thermal contact resistance based on experimental results from actual testing conditions. It has been found that predictions of limits of lubrication are possible by numerical means and that the FE...


    B. M. Musaibov


    Full Text Available The problems of intensity of wear of details of the cars working in the oil polluted by abrasive particles, depending on mechanical properties of material of details and abrasive particles, their sizes, a form and concentration, loading, temperature of a surface of friction, speed of sliding, quality of lubricant are considered. 

  3. 超载条件下空间润滑谐波减速器传动性能及摩擦磨损性能研究%Transmission Behaviors and Tribological Properties of the Solid and Grease Lubricated Harmonic Drivers at Overload Condition

    李波; 李瑞祥


    In this paper, the transmission behaviors and tribological properties of the solid and grease lubricated XB1 -60 -150 harmonic drivers were studied under a range of temperature and overload condition. The results showed that in the temperature range of -50℃ to 40℃ and overload condition below 150% , both the solid and grease lubricated harmonic drivers exhibited good transmission behaviors. The transmission efficiency of the grease lubricated harmonic driver was better than that of the solid lubricated one. However, the solid lubricated harmonic driver showed more stable transmission efficiency under different temperatures and loads. After running 1.5 × 105 r of the wave generator, a strip examination of the two harmonic drivers using an optical microscope revealed that the surface of the flexspline and the circular spline was in a good condition with no signs of inordinate wear. The lubrication in this area had thus been fully effective. In addition, the effects of temperature, lubrication mode and load on transmission behavior of the harmonic driver were analyzed with an orthogonal design method for multi - factor analysis. The analysis results showed that the influence order of the tested factors were ranked as temperature > lubrication type > load condition.%本文选用XB1-60-150型谐波减速器,考察了脂润滑与固体润滑谐波减速器在宽温度范围及不同超载条件下的传动性能,结果表明:在-50~40℃温度范围内及不超过150%超载条件下,固体润滑谐波减速器和脂润滑谐波减速器均表现出良好的运转性能.在不同载荷及温度下,脂润滑谐波减速器表现出较高的传动效率,而固体润滑谐波减速器则表现出较稳定的传动性能.在波发生器运行总次数1.5×105r后,利用光学显微镜对柔轮-刚轮齿轮摩擦副表面进行检查,未观察到明显的异常磨损,润滑状态良好.本文还采用正交试验极差分析方法,综合分析了空间润滑谐波减

  4. Several difficult problems in lubrication


    Whether in industry or in our human life, we will encounter many lubrication problems. A goodlubricant not only should have good performance, but also should meet the needs of the specific condi-tions. Here we give some examples about the difficult problems in lubrication and their solutions. Theseexamples are: (i) hydrolysis and emulsion of ZDTP; (ii) corrosion of chlorowax; (iii) coexistence of greencompressor oil and cryogen (R-134A); (iv) lubrication of cystoscope and catheter. On the same time,some achievements in lubrication field provided by Lubrication Chemistry Laboratory of Shanghai Uni-versity will be introduced in this paper.


    Surfactants are one of the most widely applied materials by consumers and industry. The application areas for surfactants span from everyday mundane tasks such as cleaning, to highly complex processes involving the formulation of pharmaceuticals, foods, pesticides, lubricants, etc. Even though sur...

  6. Natural oils as lubricants

    There is currently an availability of vegetable oil lubricants, with the exception of engine oils. Vegetable oils are environmentally friendly, renewable, contribute to the reduction of our dependence on imported petroleum, and add value to the farmer. However, there are inherent weaknesses in veg...

  7. Biobased lubricant additives

    Fully biobased lubricants are those formulated using all biobased ingredients, i.e. biobased base oils and biobased additives. Such formulations provide the maximum environmental, safety, and economic benefits expected from a biobased product. Currently, there are a number of biobased base oils that...

  8. Mixed lubricated line contacts

    Faraon, Irinel Cosmin


    The present work deals with friction in mixed lubricated line contacts. Components in systems are becoming smaller and due to, for instance power transmitted, partial contact may occur. In industrial applications, friction between the moving contacting surfaces cannot be avoided, therefore it is essential that an engineer is able to predict friction.

  9. Lubricating oil; Junkatsuyu

    Shimizu, H.


    As a reflection of business recession, sales amount of lubricating oils in 1998 in Japan was 2.334 million kl that is 96.1% of that in the previous year. In addition, export amount was 394 thousand kl that also decreased sharply to 81.9% of that in the previous year. In this situation, researches and developments of environment-adaptable lubricating oils such as fuel consumption-saving engine oils, new mechanism-corresponding drive system oils (AFT, CVT), refrigerating machine oils for substitute coolants, biodegradable oils and greases, environment corresponding processing oils (non-chlorine type cutting oils), and so on have been executed actively. In respect to lubricating oils for vehicles, numerous researches and developments of engine oils are executed while putting stress on the improvement of fuel consumption saving for reducing CO{sub 2} exhaust; improvement of adaptability to exhaust treating apparatus for purging harmful components from exhaust gas; and environmental corresponding of long drain for reducing waste oils. In respect to lubricating oils for industry, basic characteristics and utility characteristics of fire-resistant working fluids and biodegradable working fluids; and utility characteristics of new functional fluids and electric viscous fluids are reported in view of their relationship with environmental protection. (NEDO)

  10. Manufacturing processes of cellular metals. Part II. Solid route, metals deposition, other processes; Procesos de fabricacion de metales celulares. Parte II: Via solida, deposicion de metales otros procesos

    Fernandez, P.; Cruz, L. J.; Coleto, J.


    At the first part of this paper review a description about cellular metal processes by liquid route, was made. In this second part, solid processes and metals deposition are described. In similar way, the different kind of processes in each case are reviewed; making a short description about the main parameters involved and the advantages and drawbacks in each of them. (Author) 147 refs.

  11. Lubrication effectiveness of composite lubricants during P/M electrostatic die wall lubrication and warm compaction

    Xia Yang; Shiju Guo; Farid Akhtar


    The lubrication effectiveness of the composite lubricants, 50wt% ethylene bis-stearamide (EBS) wax + 50wt% graphite and 50wt% EBS wax + 50wt% BN, during the powder metallurgy (P/M) electrostatic die wall lubrication and warm compaction was studied. The results show that the combination of 50wt% EBS wax and 50wt% graphite has excellent lubrication performance, resulting in fairly high green densities, but the mixture of 50wt% EBS wax and 50wt% BN has less beneficial effect. In addition, corresponding die temperatures should be applied when different die wall lubricants are used to achieve the highest green densities.

  12. Influence of service temperature on tribological characteristics of self-lubricant coatings: A review

    Jun-Feng YANG; Yan JIANG; Jens HARDELL; Braham PRAKASH; Qian-Feng FANG


    Self-lubricating coatings have been widely used to reduce friction in moving machine assemblies. However, the tribological performance of these coatings is strongly dependent on the service temperature. In this paper, an extensive review pertaining to the influence of operating service temperature on tribological performance of self-lubricating coatings has been carried out. Based on the effective lubricating temperature range, the self-lubricating coatings developed in the past have been divided into three groups: low temperature lubricant coating (from -200℃ to room temperature), moderate temperature lubricant coating (from room temperature to 500℃) and high temperature lubricant coating (〉 500℃). Ideas concerning possible ways to extend the operating temperature range of self-lubricating coatings have been presented as follows: hybridized tribological coating, adaptive tribological coatings, and diffusion rate limited solid lubricant coating, in addition, a new self-lubricating coating formulation for potential application at a wide operating temperature range has been proposed.

  13. 41 CFR 101-26.602-1 - Procurement of lubricating oils, greases, and gear lubricants.


    ... lubricating oils, greases, and gear lubricants. 101-26.602-1 Section 101-26.602-1 Public Contracts and...-26.602-1 Procurement of lubricating oils, greases, and gear lubricants. (a) The Defense Fuel Supply Center will make annual procurements of lubricating oils, greases, and gear lubricants for ground...

  14. Pipe flow of pumping wet shotcrete based on lubrication layer.

    Chen, Lianjun; Liu, Guoming; Cheng, Weimin; Pan, Gang


    Wet shotcrete can reduce dust and improve supporting strength, however, safe and efficient pipage is a key technical part of wet shotcrete process. The paper studied the pipe flow law of wet shotcrete based on lubrication layer by build the experimental pumping circuit of wet shotcrete that can carry out a number of full-scale pumping tests. The experimental results show there was a linear relationship between pressure loss and flow rate. Combined with the Buckingham rheological equation, the computing equations of the yield shear stress and plastic viscosity were deduced through linear regression. A simple analytical method allowing for a rough estimation of the pumping pressure was proposed and used when considering the lubrication layer of wet shotcrete in pipes. In addition, two kinds of particulate distributive models were established along the time axial to analyze the formation of lubrication layer which is related with particles migration. By computational fluid dynamics simulation, the lubrication layer thickness of different mix proportions was estimated. A new method for measuring the thickness of lubrication layer was proposed to verify it by binarization processing. Finally, according to the comparative analysis of experiments, simulation and computed value, it can be seen that the lubrication layer plays a key role in the process of wet shotcrete flow and with the increase of lubrication layer thickness pipe pressure declines gradually.

  15. Lubrication of space systems

    Fusaro, Robert L.


    NASA has many high-technology programs plannned for the future, such as the space station, Mission to Planet Earth (a series of Earth-observing satellites), space telescopes, and planetary orbiters. These missions will involve advanced mechanical moving components, space mechanisms that will need wear protection and lubrication. The tribology practices used in space today are primarily based on a technology that is more than 20 years old. The question is the following: Is this technology base good enough to meet the needs of these future long-duration NASA missions? This paper examines NASA's future space missions, how mechanisms are currently lubricated, some of the mechanism and tribology challenges that may be encountered in future missions, and some potential solutions to these future challenges.

  16. Shearing stability of lubricants

    Shiba, Y.; Gijyutsu, G.


    Shearing stabilities of lubricating oils containing a high mol. wt. polymer as a viscosity index improver were studied by use of ultrasound. The oils were degraded by cavitation and the degradation generally followed first order kinetics with the rate of degradation increasing with the intensity of the ultrasonic irradiation and the cumulative energy applied. The shear stability was mainly affected by the mol. wt. of the polymer additive and could be determined in a short time by mechanical shearing with ultrasound.

  17. Shearing stability of lubricants

    Shiba, Y.; Gijyutsu, G.


    Shearing stabilities of lubricating oils containing a high mol. wt. polymer as a viscosity index improver were studied by use of ultrasound. The oils were degraded by cavitation and the degradation generally followed first order kinetics with the rate of degradation increasing with the intensity of the ultrasonic irradiation and the cumulative energy applied. The shear stability was mainly affected by the mol. wt. of the polymer additive and could be determined in a short time by mechanical shearing with ultrasound.

  18. Alternative strategies for energy recovery from municipal solid waste Part A: Mass and energy balances.

    Consonni, S; Giugliano, M; Grosso, M


    This two-part paper assesses four strategies for energy recovery from municipal solid waste (MSW) by dedicated waste-to-energy (WTE) plants generating electricity through a steam cycle. The feedstock is the residue after materials recovery (MR), assumed to be 35% by weight of the collected MSW. In strategy 1, the MR residue is fed directly to a grate combustor. In strategy 2, the MR residue is first subjected to light mechanical treatment. In strategies 3 and 4, the MR residue is converted into RDF, which is combusted in a fluidized bed combustor. To examine the relevance of scale, we considered a small waste management system (WMS) serving 200,000 people and a large WMS serving 1,200,000 people. A variation of strategy 1 shows the potential of cogeneration with district heating. The assessment is carried out by a Life Cycle Analysis where the electricity generated by the WTE plant displaces electricity generated by fossil fuel-fired steam plants. Part A focuses on mass and energy balances, while Part B focuses on emissions and costs. Results show that treating the MR residue ahead of the WTE plant reduces energy recovery. The largest energy savings are achieved by combusting the MR residue "as is" in large scale plants; with cogeneration, primary energy savings can reach 2.5% of total societal energy use.

  19. Lubricant characterization by molecular simulation

    Moore, J.D.; Cui, S.T.; Cummings, P.T.; Cochran, H.D. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemical Engineering]|[Oak Ridge National Lab., TN (United States). Chemical Technology Div.


    The authors have reported the calculation of the kinematic viscosity index of squalane from nonequilibrium molecular dynamics simulations. This represents the first accurate quantitative prediction of this measure of lubricant performance by molecular simulation. Using the same general alkane potential model, this computational approach offers the possibility of predicting the performance of potential lubricants prior to synthesis. Consequently, molecular simulation is poised to become an important tool for future lubricant development.

  20. Solid-phase cloning for high-throughput assembly of single and multiple DNA parts.

    Lundqvist, Magnus; Edfors, Fredrik; Sivertsson, Åsa; Hallström, Björn M; Hudson, Elton P; Tegel, Hanna; Holmberg, Anders; Uhlén, Mathias; Rockberg, Johan


    We describe solid-phase cloning (SPC) for high-throughput assembly of expression plasmids. Our method allows PCR products to be put directly into a liquid handler for capture and purification using paramagnetic streptavidin beads and conversion into constructs by subsequent cloning reactions. We present a robust automated protocol for restriction enzyme based SPC and its performance for the cloning of >60 000 unique human gene fragments into expression vectors. In addition, we report on SPC-based single-strand assembly for applications where exact control of the sequence between fragments is needed or where multiple inserts are to be assembled. In this approach, the solid support allows for head-to-tail assembly of DNA fragments based on hybridization and polymerase fill-in. The usefulness of head-to-tail SPC was demonstrated by assembly of >150 constructs with up to four DNA parts at an average success rate above 80%. We report on several applications for SPC and we suggest it to be particularly suitable for high-throughput efforts using laboratory workstations.

  1. Selective Surface Modification on Lubricant Retention

    Jiang, Yu; Suvanto, Mika; Pakkanen, Tapani A.


    While surface patterns are effective in improving tribological properties, nevertheless they alter the surface wettability, which will in turn affect the surface-lubricant interactions. When there is a shortage of lubricant on a patterned surface, the lubricant stored inside the cavities will be extracted to compensate the surface lubricant dissipation. Additionally, the lubricant retention effect provided by the cavities is competing with the release of the lubricant. With weak surface-lubricant interaction, the retention is limited. Therefore, the lubrication will have a sudden failure, giving a dramatic transition to abrasive wear. To improve the performance of polar lubricants on hydrophobic polymer surfaces, both topographical and selective surface modifications were incorporated on injection molded polypropylene surfaces. Distinctive lubrication improvement was observed when the surface structure density for the lubricant storage was high, and the release of the lubricant was controlled by the interaction with the selectively modified surfaces.

  2. Cooling lubricants; Kuehlschmierstoffe

    Pfeiffer, W. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Breuer, D. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Blome, H. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Deininger, C. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Hahn, J.U. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Kleine, H. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Nies, E. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Pflaumbaum, W. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Stockmann, R. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Willert, G. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Sonnenschein, G. [Maschinenbau- und Metall-Berufsgenossenschaft, Duesseldorf (Germany)


    As a rule, the base substances used are certain liquid hydrocarbons from mineral oils as well as from native and synthetic oils. Through the addition of further substances the cooling lubricant takes on the particular qualities required for the use in question. Employees working with cooling lubricants are exposed to various hazards. The assessment of the concentrations at the work station is carried out on the basis of existing technical rules for contact with hazardous substances. However, the application/implementation of compulsory investigation and supervision in accordance with these rules is made difficult by the fact that cooling lubricants are, as a rule, made up of complicated compound mixtures. In addition to protecting employees from exposure to mists and vapours from the cooling lubricants, protection for the skin is also of particular importance. Cooling lubricants should not, if at all possible, be brought into contact with the skin. Cleansing the skin and skin care is just as important as changing working clothes regularly, and hygiene and cleanliness at the workplace. Unavoidable emissions are to be immediately collected at the point where they arise or are released and safely disposed of. This means taking into account all sources of emissions. The programme presented in this report therefore gives a very detailed account of the individual protective measures and provides recommendations for the design of technical protection facilities. (orig./MG) [Deutsch] Als Basisstoffe dienen in der Regel bestimmte fluessige Kohlenwasserstoffverbindungen aus Mineraloelen sowie aus nativen oder synthetischen Oelen. Durch die Zugabe von weiteren Stoffen erlangt der Kuehlschmierstoff seine fuer den jeweiligen Anwendungsabfall geforderten Eigenschaften. Beschaeftigte, die mit Kuehlschmierstoffen umgehen, sind unterschiedliche Gefahren ausgesetzt. Die Beurteilung der Kuehlschmierstoffkonzentrationen in der Luft am Arbeitsplatz erfolgt auf der Grundlage bestehender

  3. Numerical simulation of lubrication mechanisms at mesoscopic scale

    Hubert, C.; Bay, Niels; Christiansen, Peter


    The mechanisms of liquid lubrication in metal forming are studied at a mesoscopic scale, adopting a 2D sequential fluid-solid weak coupling approach earlier developed in the first author's laboratory. This approach involves two computation steps. The first one is a fully coupled fluid-structure F......The mechanisms of liquid lubrication in metal forming are studied at a mesoscopic scale, adopting a 2D sequential fluid-solid weak coupling approach earlier developed in the first author's laboratory. This approach involves two computation steps. The first one is a fully coupled fluid......'s equation, at the asperity level, in order to quantify the fluid leakage in the cavity/plateau network using the lubricant pressure computed previously. The numerical simulation is validated by experimental tests in plane strain strip reduction of aluminium sheet provided with model cavities in form......PlastoHydroDynamic Lubrication (MPHDL) as well as cavity shrinkage due to lubricant compression and escape and strip deformation....


    LIU Kun; LIU Xiaojun; WANG Wei; JIAO Minghua


    To study the tribological properties of the piston ring-cylinder liner in liquid-solid lubrication, the experiment is carried out on a modified piston ring-cylinder liner tester. Two kinds of liquid-solid lubricants are used, one with ultra-dispersed diamond (UDD) nano-particles suspending in pure lubricant, the other with micro-sized MoS2 particles. The particle concentrations are 0%, 0.02%and 0.1% by weight. The experimental temperature is 30 ℃ and 75 ℃ respectively. The results show that with the presence of ultra-dispersed diamond particles, the load when scuffing failure occurs is increased. For the lubricant contains MoS2 particles, the scuffing load is decreased. The liquid-solid lubricant also affects the thermal behavior of piston ring-cylinder liner. The surface bulk temperatures of cylinder liner specimen are measured. It has been seen that liquid-solid lubricant used in this research tends to improve the thermal properties generally and the measured friction forces also decreases with the presence of UDD nano-particles. The surface bulk temperature when scuffing occurs is also measured. The results show that the size effect and environment temperature have obvious influence on scuffing load and scuffing temperature. With some new findings, this work is an important complement to the existing research on particle effect on lubrication, because the existing results only show one aspect of this problem.

  5. High Performing PFPE Nanofluid Lubricants Project

    National Aeronautics and Space Administration — Space missions could benefit from improved lubricant technology. PSI intends to develop novel liquid lubricant formulations which are applicable for future NASA...

  6. Improved Ionic Liquids as Space Lubricants Project

    National Aeronautics and Space Administration — Ionic liquids are candidate lubricant materials. However for application in low temperature space mechanisms their lubrication performance needs to be enhanced. UES...

  7. KSC lubricant testing program. [lubrication characteristics and corrosion resistance

    Lockhart, B. J.; Bryan, C. J.


    A program was conducted to evaluate the performance of various lubricants in use and considered for use at Kennedy Space Center (KSC). The overall objectives of the program were to: (1) determine the lubrication characteristics and relative corrosion resistance of lubricants in use and proposed for use at KSC; (2) identify materials which may be equivalent to or better than KELF-90 and Krytox 240 AC greases; and (3) identify or develop an improved lubricating oil suitable for use in liquid oxygen (LOX) pumps at KSC. It was concluded that: (1) earth gel thickened greases are very poor corrosion preventive materials in the KSC environment; (2) Halocarbon 25-5S and Braycote 656 were suitable substiutes for KELF-90 and Krytox 240 AC respectively; and (3) none of the oils evaluated possessed the necessary inertness, lubricity, and corrosion prevention characteristics for the KSC LOX pumping systems in their present configuration.

  8. Nanotribology of Symmetric and Asymmetric Liquid Lubricants

    Shinji Yamada


    Full Text Available When liquid molecules are confined in a narrow gap between smooth surfaces, their dynamic properties are completely different from those of the bulk. The molecular motions are highly restricted and the system exhibits solid-like responses when sheared slowly. This solidification behavior is very dependent on the molecular geometry (shape of liquids because the solidification is induced by the packing of molecules into ordered structures in confinement. This paper reviews the measurements of confined structures and friction of symmetric and asymmetric liquid lubricants using the surface forces apparatus. The results show subtle and complex friction mechanisms at the molecular scale.

  9. Detergent Additive for Lubricating Oils,

    The Russian patent pertains to a method of producing additives for lubricating oils . A method is known for producing an antiwear additive for... lubricating oils by processing phenols with phosphorus oxychloride, phosphoric acid esters are obtained. In order to give the additive detergent properties

  10. Solid-state microwave switches: Circuitry, manufacturing technologies and development trends. Review (Part 2)

    Berezniak, Anatolii; Korotkov, Alexander S.


    This paper presents an overview of the process and design capabilities of state-of-the-art in the field of microwave solid state switches. The paper describes types of solid state switches, switch specifications, a review of technological advances in this area. The overview results indicate that AlGaN/GaN MMICs including solid state switches are realizable.

  11. Solid-state microwave switches: circuitry, manufacturing technologies and development trends. Review (Part 1)

    Berezniak, Anatolii; Korotkov, Alexander S.


    This paper presents an overview of the process and design capabilities of state-of-the-art in the field of microwave solid state switches. The paper describes types of solid state switches, switch specifications, a review of technological advances in this area. The overview results indicate that AlGaN/GaN MMICs including solid state switches are realizable.

  12. Water lubricates hydrogen-bonded molecular machines

    Panman, Matthijs R.; Bakker, Bert H.; den Uyl, David; Kay, Euan R.; Leigh, David A.; Buma, Wybren Jan; Brouwer, Albert M.; Geenevasen, Jan A. J.; Woutersen, Sander


    The mechanical behaviour of molecular machines differs greatly from that of their macroscopic counterparts. This applies particularly when considering concepts such as friction and lubrication, which are key to optimizing the operation of macroscopic machinery. Here, using time-resolved vibrational spectroscopy and NMR-lineshape analysis, we show that for molecular machinery consisting of hydrogen-bonded components the relative motion of the components is accelerated strongly by adding small amounts of water. The translation of a macrocycle along a thread and the rotation of a molecular wheel around an axle both accelerate significantly on the addition of water, whereas other protic liquids have much weaker or opposite effects. We tentatively assign the superior accelerating effect of water to its ability to form a three-dimensional hydrogen-bond network between the moving parts of the molecular machine. These results may indicate a more general phenomenon that helps explain the function of water as the ‘lubricant of life’.

  13. Investigation on the lubrication properties of biodiesel made of Camelina Sativa and Lard esters

    Kreivaitis, Raimondas; Padgurskas, Juozas [Aleksandras Stulginskis Univ., Kaunas (Lithuania). Inst. of Power and Transport Machinery; Gumbyte, Milda [Aleksandras Stulginskis Univ., Kaunas (Lithuania). Inst. of Environment and Ecology


    The ethyl esters can be produced from renewable resources while methyl esters have petroleum based methyl part. Camelina Sativa is the potential source of oilseeds. The oil has similar properties as that of rapeseed oil. Animal fats are cheap raw material and there esters were suggested as a fuel for diesel engine by many authors. The objective of this study would be the lubrication properties of ethyl esters made of Camelina Sativa and Lard. The lubrication properties investigated using High-Frequency Reciprocating Rig (HFRR) method. The wear scar diameter represents the lubrication properties. The observed lubrication results are compared with lubrication properties of conventional diesel fuel obtained from manufacturer ''ORLEN Lietuva'' Lithuania. The results show that mixtures of diesel and biodiesel improve the lubrication properties. (orig.)

  14. Binding and lubrication of biomimetic boundary lubricants on articular cartilage.

    Samaroo, Kirk J; Tan, Mingchee; Putnam, David; Bonassar, Lawrence J


    The glycoprotein, lubricin, is the primary boundary lubricant of articular cartilage and has been shown to prevent cartilage damage after joint injury. In this study, a library of eight bottle-brush copolymers were synthesized to mimic the structure and function of lubricin. Polyethylene glycol (PEG) grafted onto a polyacrylic acid (pAA) core mimicked the hydrophilic mucin-like domain of lubricin, and a thiol terminus anchored the polymers to cartilage surfaces much like lubricin's C-terminus. These copolymers, abbreviated as pAA-g-PEG, rapidly bound to cartilage surfaces with binding time constants ranging from 20 to 39 min, and affected lubrication under boundary mode conditions with coefficients of friction ranging from 0.140 ± 0.024 to 0.248 ± 0.030. Binding and lubrication were highly correlated (r(2)  = 0.89-0.99), showing that boundary lubrication in this case strongly depends on the binding of the lubricant to the surface. Along with time-dependent and dose-dependent behavior, lubrication and binding of the lubricin-mimetics also depended on copolymer structural parameters including pAA backbone length, PEG side chain length, and PEG:AA brush density. Polymers with larger backbone sizes, brush sizes, or brush densities took longer to bind (p lubricate and protect cartilage in vivo. In copolymers with shorter pAA backbones, increasing hydrodynamic size inhibited lubrication (p lubricating efficacy as recombinant lubricins and as such have potential for in vivo treatment of post-traumatic osteoarthritis. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:548-557, 2017.

  15. Chemical deactivation of V{sub 2}O{sub 5}/WO{sub 3}-TiO{sub 2} SCR catalysts by additives and impurities from fuels, lubrication oils, and urea solution. Part 1. Catalytic studies

    Kroecher, Oliver; Elsener, Martin [Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)


    The influence of the combustion products of different lubrication oil additives (Ca, Mg, Zn, P, B, Mo) and impurities in Diesel fuel (K from raps methyl ester) or urea solution (Ca, K) on the activity and selectivity of vanadia-based SCR catalysts were investigated. Standard V{sub 2}O{sub 5}/WO{sub 3}-TiO{sub 2} catalysts coated on metal substrates (400 cpsi) were impregnated with water soluble compounds of these elements and calcined at 400 and 550 C, in order to investigate the chemical deactivation potential of different elements and combinations of them. It was found that potassium strongly reduced the adsorption equilibrium constant K{sub NH{sub 3}} of ammonia. At small ammonia concentrations in the feed, only part of the active sites were covered with ammonia resulting in a reduced SCR reaction rate. At high ammonia concentrations, the surface coverage and SCR reaction rate increased, but high SCR activity at concurrent low ammonia emissions was impossible. Calcium caused less deactivation than potassium and did not affect the ammonia adsorption to the same extent, but it lowered the intrinsic SCR reaction rate. Moreover, deactivation by calcium was much reduced if counter-ions of inorganic acids were present (order of improvement: SO{sub 4}{sup 2-} > PO{sub 4}{sup 3-} > BO{sub 3}{sup 3-}). Zinc was again less deactivating than calcium, but the positive effect of the counter-ions was weaker than in case of calcium. The degree of N{sub 2}O production at T > 500 C, which is typical for V{sub 2}O{sub 5}/WO{sub 3}-TiO{sub 2} catalysts, was not influenced by the different compounds, except for molybdenum, which induced a small increase in N{sub 2}O formation. (author)

  16. High temperature solid oxide fuel cell integrated with novel allothermal biomass gasification. Part II: Exergy analysis

    Panopoulos, K. D.; Fryda, L.; Karl, J.; Poulou, S.; Kakaras, E.

    Biomass gasification derived gas is a renewable fuel, which can be used for SOFC applications. This work investigates the integration of a near atmospheric solid oxide fuel cell (SOFC) with a novel allothermal biomass steam gasification process into a combined heat and power (CHP) system of less than MW e range. Heat for steam gasification is supplied from SOFC depleted fuel in a fluidised bed (FB) combustor via high temperature sodium heat pipes. In the first paper, the integrated system was modelled in Aspen Plus™ and critical aspects for its feasibility were identified. The aim of this second part is the evaluation of the integrated system in exergy terms. Satisfying allothermal gasification heat demand is illustrated by examining each sub-process involved separately as well as combined. For a relatively low STBR = 0.6, the SOFC fuel utilisation for which the system operates under optimum conditions is U f = 0.7. Above that value additional biomass has to be used in the FB combustor to provide gasification heat with considerable exergy losses. For SOFC operation at current density 2500 A m -2, the system uses 90 kg h -1 biomass, operates with electrical exergetic efficiency 32% producing 140 kW e, while the combined electrical and thermal exergetic efficiency is 35%.

  17. 7 CFR 2902.46 - Forming lubricants.


    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Forming lubricants. 2902.46 Section 2902.46... Items § 2902.46 Forming lubricants. (a) Definition. Products designed to provide lubrication during... forming lubricants. By that date, Federal agencies that have the responsibility for drafting or...

  18. 7 CFR 2902.38 - Firearm lubricants.


    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Firearm lubricants. 2902.38 Section 2902.38... Items § 2902.38 Firearm lubricants. (a) Definition. Lubricants that are designed for use in firearms to... qualifying biobased firearm lubricants. By that date, Federal agencies that have the responsibility...

  19. 7 CFR 2902.14 - Penetrating lubricants.


    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Penetrating lubricants. 2902.14 Section 2902.14... Items § 2902.14 Penetrating lubricants. (a) Definition. Products formulated to provide light lubrication..., will give a procurement preference for qualifying biobased penetrating lubricants. By that...


    T. A. Ahmetov


    Full Text Available Industrial testing of regenerated lubricant in the process of wire drawing showed satisfactory quality (absence of gloss. It is determined that consumption of regenerated lubricant does not differ from consumption of new lubricant. Regenerated lubricant corresponds to the requirements of normative documents.

  1. Environmental monitoring recovery of solid wastes in Muribeca (Brasil). 2 part; Monitoreo ambiental de la recuperacion del vertedero de residuos solidos de Muribeca, Brasil-II parte

    Juca, J. F. T.; Monteiro, V. E. D.; Melo, M. C.


    This paper presents a comprehensive program of studying and monitoring the in situ performance of Muribeca Landfill, Physical, chemical and biological properties of the solid waste were analyzing in order to understand the mechanics of the landfill, the waste biodegradation process and the contamination level of air, liquids and subsoil. the parameters monitored in this investigation involve from leachate and gases generation to salts variations and the evolution of bacteria growth. Climate variation, among several others environment parameters, that affects solid waste degradation in sanitary landfills, were also controlled. Temperature, settlement, physical-chemical parameters, pathogenic microorganisms determination (quantitative and qualitative) and phyto toxicity are also part of this study. Secondary determinations as: moisture content, volatile solids, pH, grains density, and metals evaluation in different depths were also investigated. (Author) 23 refs.

  2. Environmental monitoring recovery of solid wastes in Muribeca, (Brasil): 1 part; Monitoreo ambiental de la recuperacion del vertedero de residuos solidos de Muribeca, Brasil- 1 parte

    Juca, J. f. T.; Monteiro, V. E. D.; Melo, M. C.


    This paper presents a comprehensive program of studying and monitoring the in situ performance of Muribeca Landfill. Physical, chemical and biological properties of the solid waste were analyzing in order to understand the mechanics of the landfill, the waste biodegradation process and the contamination level of air, liquids and subsoil. The parameters monitored in this investigation involve from leachate and gases generation to salts variations and the evolution of bacteria growth. Climate variation, among several others environment parameters, that affects solid waste degradation in sanitary landfills, were also controlled. Temperature, settlement, physical-chemical parameters, pathogenic microorganisms determination (quantitative and qualitative) and phytotoxicity are also part of this study. Secondary determinations as: moisture content, volatile solids, pH, grains density, and metals, evaluation in different depths were also investigated. (Author)

  3. Efficient numerical method for computation of thermohydrodynamics of laminar lubricating films

    Elrod, Harold G.


    The purpose of this paper is to describe an accurate, yet economical, method for computing temperature effects in laminar lubricating films in two dimensions. The procedure presented here is a sequel to one presented in Leeds in 1986 that was carried out for the one-dimensional case. Because of the marked dependence of lubricant viscosity on temperature, the effect of viscosity variation both across and along a lubricating film can dwarf other deviations from ideal constant-property lubrication. In practice, a thermohydrodynamics program will involve simultaneous solution of the film lubrication problem, together with heat conduction in a solid, complex structure. The extent of computation required makes economy in numerical processing of utmost importance. In pursuit of such economy, we here use techniques similar to those for Gaussian quadrature. We show that, for many purposes, the use of just two properly positioned temperatures (Lobatto points) characterizes well the transverse temperature distribution.

  4. Linear and Non-Linear Control Techniques Applied to Actively Lubricated Journal Bearings

    Nicoletti, Rodrigo; Santos, Ilmar


    The main objectives of actively lubricated bearings are the simultaneous reduction of wear and vibration between rotating and stationary machinery parts. For reducing wear and dissipating vibration energy until certain limits, one can count with the conventional hydrodynamic lubrication. For furt...

  5. 49 CFR 215.109 - Defective plain bearing box: Journal lubrication system.


    ... 49 Transportation 4 2010-10-01 2010-10-01 false Defective plain bearing box: Journal lubrication... Freight Car Components Suspension System § 215.109 Defective plain bearing box: Journal lubrication system...) Metal parts contacting the journal; or (e) Is— (1) Missing; or (2) Not in contact with the journal....

  6. Property Analysis of the Agricultural Machinery Lubricants

    Tone Ploj


    Full Text Available We need to produce enough healthy and cheap food as well as to preserve the ecologic equilibrium. This can be achived by using modern machinery and up- to-date knowledge and technology. Agricultural machinery, in which 40-60% of all funds are invested, is poorly maintained and underused. The main causes for this are poor knowledge and extensive farm land fragmentation. The fact that over 140,000 tractors in Slovenia are on average 9.6 years old, i.e. that more than 80% of overall agricultural machinery is obsolete, should be a matter of serious concern. In the paper we follow tribological conditions in particular tractor assemblies. In the first part of the paper we have treated the required conditions of tractor manufacturers in Europe and primarily in Slovenia, what has served us in the final phase of the research for elaboration of the model. In this way we have got data about the presence of particular tractor types. We have separately elaborated the necessary specifications of engine lubricants, transmission, gears, hydraulics and wet breaks. We have carried out chemical and mechanical analyses of all accessible lubricants in agricultural mechanisation. The results of the new oils were coordinated with the required specifications of tractor manufacturers and so we have got such a model, that certainly meet all lubricating requirements of our tractors.

  7. Tribological Properties of Fe-Ni Matrix Solid Self-lubricant Composite at High Temperature%Fe-Ni基高温自润滑复合材料摩擦磨损特性研究

    郭志成; 李长生; 唐华; 阎逢元; 孙建荣; 刘金银子


    本文中采用滑动磨损试验方法研究了以PbO和WS2为润滑组元的复合材料与440C不锈钢配副在25~600℃温度范围内的摩擦磨损特性.通过X射线衍射仪分析发现复合材料中含有铬的硫化物等高温润滑物质生成.使用扫描电镜和金相显微镜进一步分析了材料摩擦表面形貌.结果表明:在500 ~ 600℃范围内,PbWO4、CrxSx+1等各种金属化合物在摩擦表面形成了较完整的润滑膜,产生了自润滑能力,具有优良的减摩耐磨性能.润滑膜材料可向摩擦对偶表面转移,在一定程度上阻止了复合材料与440C不锈钢对摩材料的直接接触,显著降低了材料摩擦系数和磨损率,实现了高温自润滑性能.本文进一步探索了单一润滑组元润滑膜和两种润滑组元润滑膜的承载能力,发现两种固体润滑组元产生的协同润滑效应显著改善了润滑膜的润滑性能.%Property has generated immense attention.The tribological behaviors of self-lubricating composite containing PbO and WS2 in sliding against 440C stainless steel were evaluated at temperatures ranging from 25 to 600 ℃.Chromium sulfides were found in the composite at elevated temperature bv XRD.The worn surface of the composite was examined by using scanning electron microscope and metallographic microscope.The results reveal that an intact lubricant film composing of PbWO4 and CrxSx+1-type eutectic compound formed on the friction surface at 500 ~600 ℃.Wear type of tested composite material/440C stainless steel was the transfer of the lubricant film to the surface of 440C stainless steel,making the friction coefficient of material sharply lower.This paper further explore the difference of the bearing capacity of the lubricant films generated by the single lubricating element and two lubricating elements.It is found that synergetic lubricating effect of two lubricating elements significantly improved the tribological property.

  8. Grease lubrication mechanisms in bearing seals


    Rolling bearings contain seals to keep lubricant inside and contaminants outside the bearing system. These systems are often lubricated with grease; the grease acts as a lubricant for the bearing and seal and improves the sealing efficiency. In this thesis, the influence of lubricating grease on bearing seal performance is studied. Rheological properties of the grease, i.e. shear stress and normal stress difference, are evaluated and related to the lubricating and sealing performance of the s...

  9. Hydration lubrication and shear-induced self-healing of lipid bilayer boundary lubricants in phosphatidylcholine dispersions.

    Sorkin, Raya; Kampf, Nir; Zhu, Linyi; Klein, Jacob


    Measurements of normal and shear (frictional) forces between mica surfaces across small unilamellar vesicle (SUV) dispersions of the phosphatidylcholine (PC) lipids DMPC (14:0), DPPC (16:0) and DSPC (18:0) and POPC (16:0, 18:1), at physiologically high pressures, are reported. We have previously studied the normal and shear forces between two opposing surfaces bearing PC vesicles across pure water and showed that liposome lubrication ability improved with increasing acyl chain length, and correlated strongly with the SUV structural integrity on the substrate surface (DSPC > DPPC > DMPC). In the current study, surprisingly, we discovered that this trend is reversed when the measurements are conducted in SUV dispersions, instead of pure water. In their corresponding SUV dispersion, DMPC SUVs ruptured and formed bilayers, which were able to provide reversible and reproducible lubrication with extremely low friction (μ lubrication, but with slightly higher friction coefficients (μ = 10(-3)-10(-4)). We believe these differences originate from fast self-healing of the softer surface layers (which are in their liquid disordered phase, POPC, or close to it, DMPC), which renders the robustness of the DPPC or DSPC (both in their solid ordered phase) less important in these conditions. Under these circumstances, the enhanced hydration of the less densely packed POPC and DMPC surface layers is now believed to play an important role, and allows enhanced lubrication via the hydration lubrication mechanism. Our findings may have implications for the understanding of complex biological systems such us biolubrication of synovial joints.

  10. Lubricant Foaming and Aeration Study. Part 1


    Code) 10. SOURCE OF FUNDING NOS. PR(.GRAM PROJECT TASK WORK UNIT ELEMENT NO. NO. NO. NO. 11. TITLE (Include Security Clasification ) I ILUBRICAN4T...synthetic. The best known examples in aqueous systems are solutions of water-soluble proteins , such as casein or albumen. Common examples are the stable...liquid surface. A layer of denatured protein that stabilizes the foam of meringue, or of whipped cream, or of beer, is a common example. c

  11. Friction laws for lubricated nanocontacts

    Buzio, R.; Boragno, C.; Valbusa, U.


    We have used friction force microscopy to probe friction laws for nanoasperities sliding on atomically flat substrates under controlled atmosphere and liquid environment, respectively. A power law relates friction force and normal load in dry air, whereas a linear relationship, i.e., Amontons' law, is observed for junctions fully immersed in model lubricants, namely, octamethylciclotetrasiloxane and squalane. Lubricated contacts display a remarkable friction reduction, with liquid and substrate specific friction coefficients. Comparison with molecular dynamics simulations suggests that load-bearing boundary layers at junction entrance cause the appearance of Amontons' law and impart atomic-scale character to the sliding process; continuum friction models are on the contrary of limited predictive power when applied to lubrication effects. An attempt is done to define general working conditions leading to the manifestation of nanoscale lubricity due to adsorbed boundary layers.

  12. Environmentally friendly and biobased lubricants

    Biobased and environmentally friendly lubricants are finding applications in many areas ranging from hydraulic fluids to grease. They offer excellent biodegradability and very low ecotoxicity; high viscosity index; improved tribological properties; lower volatility and flash points relative to petro...

  13. Structural lubricity under ambient conditions

    Cihan, Ebru; Ipek, Semran; Durgun, Engin; Baykara, Mehmet Z.


    Despite its fundamental importance, physical mechanisms that govern friction are poorly understood. While a state of ultra-low friction, termed structural lubricity, is expected for any clean, atomically flat interface consisting of two different materials with incommensurate structures, some associated predictions could only be quantitatively confirmed under ultra-high vacuum (UHV) conditions so far. Here, we report structurally lubric sliding under ambient conditions at mesoscopic (~4,000-130,000 nm2) interfaces formed by gold islands on graphite. Ab initio calculations reveal that the gold-graphite interface is expected to remain largely free from contaminant molecules, leading to structurally lubric sliding. The experiments reported here demonstrate the potential for practical lubrication schemes for micro- and nano-electromechanical systems, which would mainly rely on an atomic-scale structural mismatch between the slider and substrate components, via the utilization of material systems featuring clean, atomically flat interfaces under ambient conditions.

  14. Enhanced condensation on lubricant-impregnated nanotextured surfaces.

    Anand, Sushant; Paxson, Adam T; Dhiman, Rajeev; Smith, J David; Varanasi, Kripa K


    Nanotextured superhydrophobic surfaces have received significant attention due to their ability to easily shed liquid drops. However, water droplets have been shown to condense within the textures of superhydrophobic surfaces, impale the vapor pockets, and strongly pin to the surface. This results in poor droplet mobility and degrades condensation performance. In this paper, we show that pinning of condensate droplets can be drastically reduced by designing a hierarchical micro-nanoscale texture on a surface and impregnating it with an appropriate lubricant. The choice of lubricant must take into account the surface energies of all phases present. A lubricant will cloak the condensate and inhibit growth if the spreading coefficient is positive. If the lubricant does not fully wet the solid, we show how condensate-solid pinning can be reduced by proper implementation of nanotexture. On such a surface, condensate droplets as small as 100 μm become highly mobile and move continuously at speeds that are several orders of magnitude higher than those on identically textured superhydrophobic surfaces. This remarkable mobility produces a continuous sweeping effect that clears the surface for fresh nucleation and results in enhanced condensation.

  15. Determination of the aromatic hydrocarbon to total hydrocarbon ratio of mineral oil in commercial lubricants.

    Uematsu, Yoko; Suzuki, Kumi; Ogimoto, Mami


    A method was developed to determine the aromatic hydrocarbon to total hydrocarbon ratio of mineral oil in commercial lubricants; a survey was also conducted of commercial lubricants. Hydrocarbons in lubricants were separated from the matrix components of lubricants using a silica gel solid phase extraction (SPE) column. Normal-phase liquid chromatography (NPLC) coupled with an evaporative light-scattering detector (ELSD) was used to determine the aromatic hydrocarbon to total hydrocarbon ratio. Size exclusion chromatography (SEC) coupled with a diode array detector (DAD) and a refractive index detector (RID) was used to estimate carbon numbers and the presence of aromatic hydrocarbons, which supplemented the results obtained by NPLC/ELSD. Aromatic hydrocarbons were not detected in 12 lubricants specified for use for incidental food contact, but were detected in 13 out of 22 lubricants non-specified for incidental food contact at a ratio up to 18%. They were also detected in 10 out of 12 lubricants collected at food factories at a ratio up to 13%. The centre carbon numbers of hydrocarbons in commercial lubricants were estimated to be between C16 and C50.

  16. New directions in lubrication, materials, wear, and surface interactions - Tribology in the 80's

    Loomis, W. R. (Editor)


    New directions in tribology are described. A range of topics is addressed, extending from fundamental research on tribological materials of all kinds and their surface effects, to final technological applications in mechanical components such as bearings, gears, and seals. The general topics addressed include: importance and definition of materials in tribology; future directions of research in adhesion and friction, wear and wear-resistant materials, and liquid lubricants and additives; status and new directions in elastohydrodynamic lubrication and solid lubricants; and tribological materials for mechanical components of the future.

  17. SEACAS Theory Manuals: Part 1. Problem Formulation in Nonlinear Solid Mechancis

    Attaway, S.W.; Laursen, T.A.; Zadoks, R.I.


    This report gives an introduction to the basic concepts and principles involved in the formulation of nonlinear problems in solid mechanics. By way of motivation, the discussion begins with a survey of some of the important sources of nonlinearity in solid mechanics applications, using wherever possible simple one dimensional idealizations to demonstrate the physical concepts. This discussion is then generalized by presenting generic statements of initial/boundary value problems in solid mechanics, using linear elasticity as a template and encompassing such ideas as strong and weak forms of boundary value problems, boundary and initial conditions, and dynamic and quasistatic idealizations. The notational framework used for the linearized problem is then extended to account for finite deformation of possibly inelastic solids, providing the context for the descriptions of nonlinear continuum mechanics, constitutive modeling, and finite element technology given in three companion reports.

  18. First studies of the pyrolysis of polyethylene as a part of municipal solid waste

    Bilbao, R.; Mastral, J.F.; Aldea, M.E.; Abrego, J.R. [University of Zaragoza (Spain)


    In this work, the pyrolysis of polyethylene in a fluidized bed has been studied. The experimental system is based on the WFPP technology with discontinuous feeding of the solid. Three different operating temperatures were used: 600, 700 and 800{sup o}C. For each temperature, the yield to solids, liquids and gases was calculated. The distribution of light hydrocarbons in the gaseous fraction was also determined. (author)

  19. Part II: bioavailability in beagle dogs of nimodipine solid dispersions prepared by hot-melt extrusion.

    Zheng, Xin; Yang, Rui; Zhang, Yu; Wang, Zhijun; Tang, Xing; Zheng, Liangyuan


    The aim of the present work was to investigate the in vitro dissolution properties and oral bioavailability of three solid dispersions of nimodipine. The solid dispersions were compared with pure nimodipine, their physical mixtures, and the marketed drug product Nimotop. Nimodipine solid dispersions were prepared by a hot-melt extrusion process with hydroxypropyl methylcellulose (HPMC, Methocel E5), polyvinylpyrrolidone/vinyl acetate copolymer (PVP/VA, Plasdone S630), and ethyl acrylate, methyl methacrylate polymer (Eudragit EPO). Previous studies of XRPD and DSC data showed that the crystallinity was not observed in hot-melt extrudates, two T(g)s were observed in the 30% and 50% NMD-HPMC samples, indicating phase separation. The weakening and shift of the N-H stretching vibration of the secondary amine groups of nimodipine as determined by FT-IR proved hydrogen bonding between the drug and polymers in the solid dispersion. The dissolution profiles of the three dispersion systems showed that the release was improved compared with the unmanipulated drug. Drug plasma concentrations were determined by HPLC, and pharmacokinetic parameters were calculated after orally administering each preparation containing 60 mg of nimodipine. The mean bioavailability of nimodipine was comparable after administration of the Eudragit EPO solid dispersion and Nimotop, but the HPMC and PVP/VA dispersions exhibited much lower bioavailability. However, the AUC(0-12 hr) values of all three solid dispersions were significantly higher than physical mixtures with the same carriers and nimodipine powder.

  20. State-of-the-Art of Extreme Pressure Lubrication Realized with the High Thermal Diffusivity of Liquid Metal.

    Li, Haijiang; Tian, Pengyi; Lu, Hongyu; Jia, Wenpeng; Du, Haodong; Zhang, Xiangjun; Li, Qunyang; Tian, Yu


    Sliding between two objects under very high load generally involves direct solid-solid contact at molecular/atomic level, the mechanism of which is far from clearly disclosed yet. Those microscopic solid-solid contacts could easily lead to local melting of rough surfaces. At extreme conditions, this local melting could propagate to the seizure and welding of the entire interface. Traditionally, the microscopic solid-solid contact is alleviated by various lubricants and additives based on their improved mechanical properties. In this work, we realized the state-of-the-art of extreme pressure lubrication by utilizing the high thermal diffusivity of liquid metal, 2 orders of magnitude higher than general organic lubricants. The extreme pressure lubrication property of gallium based liquid metal (GBLM) was compared with gear oil and poly-α-olefin in a four-ball test. The liquid metal lubricates very well at an extremely high load (10 kN, the maximum capability of a four-ball tester) at a rotation speed of 1800 rpm for a duration of several minutes, much better than traditional organic lubricants which typically break down within seconds at a load of a few kN. Our comparative experiments and analysis showed that this superextreme pressure lubrication capability of GBLM was attributed to the synergetic effect of the ultrafast heat dissipation of GBLM and the low friction coefficient of FeGa3 tribo-film. The present work demonstrated a novel way of improving lubrication capability by enhancing the lubricant thermal properties, which might lead to mechanical systems with much higher reliability.

  1. Friction and Wear of Dimpled Surface of Al2 O3/TiC Ceramic Tool Material Filled with MoS2 Solid Lubricants%镶嵌MoS2的Al203/TiC基陶瓷刀具材料微孔表面摩擦磨损性能研究

    邢佑强; 邓建新; 吴泽; 连云崧; 陈扬; 李士鹏


    Dimples with diameter of 50 μm on Al2O3/TiC ceramic surface were produced by Nd: YAG laser,and were filled with MoS2 solid lubricants. The tribological properties of the dimpled surface against a 440C stainless steel ball were investigated by sliding tests. The morphology of the dimple and micrograph of worn surface were observed using an optical microscope,white light interferometer,and scanning electron microscope(SEM). The results show that the dimpled surface filled with MoS2 solid lubricants exhibits lower friction coefficients and excellent anti-wear properties compared with non-dimpled surface,because the MoS2 film in the space between the dimples is formed by mechanical engagement of particles in the rough surface and solid lubricants in dimples. The friction coefficient and wear rate are reduced by supply of solid lubricants from the dimples to the surface,bulges and TiO2 formed after laser texturing. The main wear mechanism of non-dimpled surface is brittle fracture and a few ploughs, and SEM photographs indicate that dimpled surface can decrease ploughs and the main wear occurrs around the dimples.%采用Nd:YAG激光器在Al2O3/TiC陶瓷刀具材料表面加工出不同密度的微孔,并涂覆填装MoS2固体润滑剂,在UMT-2摩擦磨损试验机上进行往复摩擦试验,研究其在不同载荷和速度下的摩擦磨损性能,通过白光干涉仪、光学显微镜和扫描电镜观察激光织构化后表面特征和磨损后表面形貌.结果表明:激光织构化后,陶瓷材料表面发生了氧化;在相同的实验条件下,与光滑表面相比较,填装MoS2固体润滑剂的微孔表面能够有效地降低摩擦因数,减小磨损率.这主要是由于填装在微孔中的润滑剂在摩擦作用下涂覆到基体表面,形成润滑膜,起到减摩降磨作用,同时激光加工后微孔周围凸起及氧化后形成的摩擦特性优良的TiO2也能起到良好的减摩降磨效果.通过对磨损形貌分析,光滑表面磨损较为

  2. EHD lubricating layer

    Shvarts, I.A.


    The simplest model of an EHD lubricating layer consists of a unipolarly charged nonconducting viscous fluid between two parallel or slightly inclined nonconducting plates. The performance of such a layer is analyzed here on the basis of the fundamental EHD equations, with a plane-parallel approximation of the flow of a thin layer under a variable upper boundary. The results of the solution indicate that the bearing capacity of such a layer between parallel plates does not depend on the viscosity of the fluid, but is proportional to the energy density of the electric field in vacuum. With the plates not parallel, the bearing capacity depends on the mobility and the diffusion of the charged fluid particles. In either case the energy of the electric field can be made to compensate for the energy dissipation due to viscous friction, and in this case or with overcompensation such as EHD bearing becomes an EHD generator. Most valuable for practical applications are fluids with a high dielectric permittivity, such as ammonia and hydrogen chloride at cryogenic temperatures. 5 references, 1 figure.

  3. An Experimental Study of Soft Lubrication

    Wu, Qianhong; Gacka, Thomas; Nathan, Rungun; Wu, Li-Zhu; Cbmss Team


    Lift generation in soft porous media, as a planing surface glides over it, is a new topic in porous media flow with superior potential for lubrication and squeeze damping. This paper presents the first experimental study of this phenomenon. The experimental setup consists of a running conveyer belt covered with a soft porous sheet, and a stationary instrumented inclined planar upper board. Twelve pressure transducers mounted on the upper board captured the pore pressure generation, while a load cell was used to capture the total lifting force, arising from both the pore pressure and the compression of the solid fibers. One finds that the pore pressure distribution is consistent with theoretical predictions (Feng and Weinbaum, JFM, 2000; Wu et al., MSSE, 2006, 2011), and depends on the running belt velocity, U, the mechanical properties of the porous material, and the compression ratios of the porous layer. For a typical trial (h2/h1=5,h2/h0=1, U=3.8 m/s, where h2, h1, and h0 are the leading edge, trailing edge, and undeformed porous layer thicknesses, respectively), 68% of the lifting force was generated by the pore pressure. It conclusively demonstrates the validity of using soft porous materials for super lubrication. applications. Villanova Cellular Biomechanics and Sports Science Laboratory.

  4. Dry Lubricant Smooths the Way for Space Travel, Industry


    Reviving industry standards for coating parts in tungsten disulfide, a dry lubricant developed for the Mariner space probes managed by the Jet Propulsion Laboratory in the 1960s and '70s, Applied Tungstenite, a relatively new Temecula, California-based company, has found a client base in the mushrooming commercial space industry, as well as other manufacturers.

  5. Engine lubrication circuit including two pumps

    Lane, William H.


    A lubrication pump coupled to the engine is sized such that the it can supply the engine with a predetermined flow volume as soon as the engine reaches a peak torque engine speed. In engines that operate predominately at speeds above the peak torque engine speed, the lubrication pump is often producing lubrication fluid in excess of the predetermined flow volume that is bypassed back to a lubrication fluid source. This arguably results in wasted power. In order to more efficiently lubricate an engine, a lubrication circuit includes a lubrication pump and a variable delivery pump. The lubrication pump is operably coupled to the engine, and the variable delivery pump is in communication with a pump output controller that is operable to vary a lubrication fluid output from the variable delivery pump as a function of at least one of engine speed and lubrication flow volume or system pressure. Thus, the lubrication pump can be sized to produce the predetermined flow volume at a speed range at which the engine predominately operates while the variable delivery pump can supplement lubrication fluid delivery from the lubrication pump at engine speeds below the predominant engine speed range.

  6. Development of lubricant test for punching and blanking

    Olsson, David Dam


    The background for development of new lubricants Requirements to lubricant test for punching Methods of evaluating lubricants Test equipment developed at DTU Conclusion.......The background for development of new lubricants Requirements to lubricant test for punching Methods of evaluating lubricants Test equipment developed at DTU Conclusion....

  7. Ionic Liquids as Novel Lubricants and /or Lubricant Additives

    Qu, J. [ORNL; Viola, M. B. [General Motors Company


    This ORNL-GM CRADA developed ionic liquids (ILs) as novel lubricants or oil additives for engine lubrication. A new group of oil-miscible ILs have been designed and synthesized with high thermal stability, non-corrosiveness, excellent wettability, and most importantly effective anti-scuffing/anti-wear and friction reduction characteristics. Mechanistic analysis attributes the superior lubricating performance of IL additives to their physical and chemical interactions with metallic surfaces. Working with a leading lubricant formulation company, the team has successfully developed a prototype low-viscosity engine oil using a phosphonium-phosphate IL as an anti-wear additive. Tribological bench tests of the IL-additized formulated oil showed 20-33% lower friction in mixed and elastohydrodynamic lubrication and 38-92% lower wear in boundary lubrication when compared with commercial Mobil 1 and Mobil Clean 5W-30 engine oils. High-temperature, high load (HTHL) full-size engine tests confirmed the excellent anti-wear performance for the IL-additized engine oil. Sequence VID engine dynamometer tests demonstrated an improved fuel economy by >2% for this IL-additized engine oil benchmarked against the Mobil 1 5W-30 oil. In addition, accelerated catalyst aging tests suggest that the IL additive may potentially have less adverse impact on three-way catalysts compared to the conventional ZDDP. Follow-on research is needed for further development and optimization of IL chemistry and oil formulation to fully meet ILSAC GF-5 specifications and further enhance the automotive engine efficiency and durability.

  8. Top-of-Rail lubricant

    Alzoubi, M. F.; Fenske, G. R.; Erck, R. A.; Boparai, A. S.


    Analysis of the volatile and semivolatile fractions collected after use of the TOR lubricant indicated that other than contaminants in the collection laboratory, no compounds on the EPA's Target Compound Lists (Tables 2 and 5) were detected in these fractions. The data of these qualitative analyses, given in the various tables in the text, indicate only the relative amounts of the tentatively identified compounds. The authors recommend that quantitative analysis be performed on the volatile and semivolatile fractions to allow confirmation of the tentatively identified compounds and to obtain absolute amounts of the detected compounds. Additionally, the semivolatile fraction should be analyzed by liquid chromatography/mass spectrometry to identify compounds that are not chromatographable under the temperature program used for determination of semivolatile compounds. Introducing the top-of-rail (TOR) lubricant into the wheel/rail interface results in a reduction of almost 60% of lateral friction force over the forces encountered under dry conditions. This reveals good potential for energy savings, as well as wear reduction, for railroad companies. In TOR lubrication, an increase in the angle of attack and axle load results in increased lateral friction and rate of lubricant consumption. The most efficient TOR lubricant quantity to be used in the wheel/rail interface must be calculated precisely according to the number of cars, axle loads, train speed, and angle of attack.

  9. Report: citizen participation as a part of integrated solid waste management: Porto Alegre case.

    Bortoleto, Ana Paula; Hanaki, Keisuke


    This study presents the effects of citizen participation on integrated solid waste management. Porto Alegre was chosen as the area of study since its system is a good example for developing countries, based on the partnership between local government and the former scavengers' association that implements selective collection in the city. A life-cycle approach was used to estimate environmental loadings and economic costs based on solid waste generation, and a survey assessment tool was used to analyse social aspects. The results showed a decrease in environmental and economic impacts in the current situation, allowing Porto Alegre to have one of the most affordable integrated solid waste management systems in Brazil. The survey assessment pointed out that public campaign changed the perceptions and practices of most of Porto Alegre's citizens regarding solid waste management. On the other hand, it also pointed out that citizens need more education to increase their participation. Therefore, more research is needed to increase cooperation among all stakeholders, improve citizen participation, and consequently, further decrease the environmental impacts and economic costs.

  10. Bio-based lubricants for numerical solution of elastohydrodynamic lubrication

    Cupu, Dedi Rosa Putra; Sheriff, Jamaluddin Md; Osman, Kahar


    This paper presents a programming code to provide numerical solution of elastohydrodynamic lubrication problem in line contacts which is modeled through an infinite cylinder on a plane to represent the application of roller bearing. In this simulation, vegetable oils will be used as bio-based lubricants. Temperature is assumed to be constant at 40°C. The results show that the EHL pressure for all vegetable oils was increasing from inlet flow until the center, then decrease a bit and rise to the peak pressure. The shapes of EHL film thickness for all tested vegetable oils are almost flat at contact region.

  11. Method For Testing Properties Of Corrosive Lubricants

    Ohi, James; De La Cruz, Jose L.; Lacey, Paul I.


    A method of testing corrosive lubricating media using a wear testing apparatus without a mechanical seal. The wear testing apparatus and methods are effective for testing volatile corrosive lubricating media under pressure and at high temperatures.

  12. Solid waste integrated cost analysis model: 1991 project year report. Part 2


    The purpose of the City of Houston`s 1991 Solid Waste Integrated Cost Analysis Model (SWICAM) project was to continue the development of a computerized cost analysis model. This model is to provide solid waste managers with tool to evaluate the dollar cost of real or hypothetical solid waste management choices. Those choices have become complicated by the implementation of Subtitle D of the Resources Conservation and Recovery Act (RCRA) and the EPA`s Integrated Approach to managing municipal solid waste;. that is, minimize generation, maximize recycling, reduce volume (incinerate), and then bury (landfill) only the remainder. Implementation of an integrated solid waste management system involving all or some of the options of recycling, waste to energy, composting, and landfilling is extremely complicated. Factors such as hauling distances, markets, and prices for recyclable, costs and benefits of transfer stations, and material recovery facilities must all be considered. A jurisdiction must determine the cost impacts of implementing a number of various possibilities for managing, handling, processing, and disposing of waste. SWICAM employs a single Lotus 123 spreadsheet to enable a jurisdiction to predict or assess the costs of its waste management system. It allows the user to select his own process flow for waste material and to manipulate the model to include as few or as many options as he or she chooses. The model will calculate the estimated cost for those choices selected. The user can then change the model to include or exclude waste stream components, until the mix of choices suits the user. Graphs can be produced as a visual communication aid in presenting the results of the cost analysis. SWICAM also allows future cost projections to be made.

  13. Dynamics of SAMs in Boundary Lubrication

    J. Manojlović


    Full Text Available Surfactant molecules have some properties responsible for a number ofremarkable phenomena, such as oriented adsorption of surfactants at surfaces and interfaces. The capability to self -assemble into well- defined structures is often seen as being more important than their surface activity. When a surfactant solution is in contact with a solid surface, the surfactant molecules adsorb onto the surface, ideally forming an adsorbed layer of a high order, termed as a self- assembled monolayer (SAM. Many surface properties are influenced bysuch a film, and therefore, SAMs offer the capability to form ordered organic surface coatings, suitable for various applications, such as wetting or corrosion protection. Due to the flexibility in choosing the molecular architecture, organic molecules have many interesting applications, such as biosensors, in Photoelectronics, in controlling water adsorption or boundary lubricant coating. This paper Focuses on cationic surfactants (quaternary ammonium surfactants with some unique properties that are not present in other surfactants.




    Full Text Available Increased thermal efficiency, savings in the fuel consumption and the possibility to burn low quality fuels conducted to an intense development of marine engines in past 20 years, this progress being emphasized by the increased combustion pressures and better combustion properties. These improvements represent a continuous challenge for lubricating oil manufacturers: the rise in combustion temperatures and pressures is making difficult to preserve the oil film in critical areas and the longer strokes of the piston leads to issues of spreading the oil. Adding here the new type of engines using gas or biofuel which requires different types of lubricating oils. Therefore, the success of new generation of engines will depend on lubricating oils quality. :

  15. Tethered Lubricants for Small Systems

    Lynden A. Archer


    The objective of this research project is two-fold. First, to fundamentally understand friction and relaxation dynamics of polymer chains near surfaces; and second, to develop novel self-lubricated substrates suitable for MEMS devices. During the three-year performance period of this study the PI and his students have shown using theory and experiments that systematic introduction of disorder into tethered lubricant coatings (e.g. by using self-assembled monolayer (SAM) mixtures or SAMs with nonlinear, branched architectures) can be used to significantly reduce the friction coefficient of a surface. They have also developed a simple procedure based on dielectric spectroscopy for quantifying the effect of surface disorder on molecular relaxation in lubricant coatings. Details of research accomplishments in each area of the project are described in the body of the report.

  16. Semi-solid Thixoforming Simulation of Al-Cu-Mn-Ti Alloy Parts via AnyCasting

    Ping WANG; Jianzhong CUI; Guimin LU


    The software AnyCasting was used to simulate the thixotropic die-casting process of semi-solid Al-Cu-Mn-Ti alloy slurry to form the parts of a particular shape, especially on how the in-gate size of die and injection speed affect the process. The results showed that the die cavity can be filled well with the semi-solid slurry in form of laminar flow under conditions that the temperature of the semi-solid slurry is 640℃ and that of die 200-240 ℃, thickness of in-gate is 11 mm and, more important, the injection speed should be changed from 0.1 to 1.0 m/s when 60% of die cavity has been filled. The simulation result is highly proved in conformity to the actual die-casting specimens in accordance to the filling process as simulated. Moreover, the hardness of the specimens is up to 116.6 HV after the treatment of solid solution plus underaging, i.e. 45.7% higher than that in conventional ones.

  17. Rise of Air Bubbles in Aircraft Lubricating Oils

    Robinson, J. V.


    Lubricating and antifoaming additives in aircraft lubricating oils may impede the escape of small bubbles from the oil by forming shells of liquid with a quasi-solid or gel structure around the bubbles. The rates of rise of small air bubbles, up to 2 millimeters in diameter, were measured at room temperature in an undoped oil, in the same oil containing foam inhibitors, and in an oil containing lubricating additives. The apparent diameter of the air bubbles was measured visually through an ocular micrometer on a traveling telescope. The bubbles in the undoped oil obeyed Stokes' Law, the rate of rise being proportional to the square of the apparent diameter and inversely proportional to the viscosity of the oil. The bubbles in the oils containing lubricating additives or foam inhibitors rose more slowly than the rate predicted by Stokes 1 Law from the apparent diameter, and the rate of rise decreased as the length of path the bubbles traveled increased. A method is derived to calculate the thickness of the liquid shell which would have to move with the bubbles in the doped oils to account for the abnoi'I!l8.lly slow velocity. The maximum thickness of this shell, calculated from the velocities observed, was equal to the bubble radius.

  18. Keeping Your Compressor Healthy: Developing the Right Lubricant Formulation is the Key

    Karnaz, Joseph A.; Kultgen, Derek W.


    Selecting the correct compressor lubricant is crucial to the duration of the compressor and the refrigerant systems’ useful life. However, developing an optimized lubricant for a refrigeration system requires a multitude of screenings and tests. The compatibility and stability of the lubricant with the refrigerant and compressor components needs to be examined at various accelerated conditions. The lubricant and refrigerant working viscosity must be determined at various refrigerant concentrations, temperatures and pressures as the diluted refrigerant in the lubricant has a significant effect on the viscosity. The correct lubricant formulation needs to be investigated for optimal performance. A compressor lubricant can provide many benefits to a refrigeration system such as bearing durability, sealing, and increased efficiency. Sometimes it is necessary to formulate the lubricant in order to optimize system performance. Specifically, this study investigated anti-wear properties of different oil additives to create a more robust refrigeration system. Many different additives and concentrations were considered and screened. Pending a successful screen test; these different additives’ anti-wear properties were analyzed using bench top tribology tests. To reduce uncertainty and provide more in-situ results the different additives were operated in a refrigerant compressor on a gas-loop testing apparatus. Oil samples were taken periodically during the test duration for analysis. Lastly, upon test completion the compressors were dismantled and the parts were examined to determine the effectiveness of the anti-wear additives.

  19. Physicochemical characterization of Au/CeO{sub 2} solids. Part 2: The impregnation preparation method

    Aboukaies, Antoine, E-mail: [Univ Lille Nord de France, 59000 Lille (France); Equipe Catalyse, UCEIV, E.A. 4492, MREI, ULCO, 59140 Dunkerque (France); Aouad, Samer [Univ Lille Nord de France, 59000 Lille (France); Equipe Catalyse, UCEIV, E.A. 4492, MREI, ULCO, 59140 Dunkerque (France); Department of Chemistry, University of Balamand, P.O. Box 100, Tripoli (Lebanon); El-Ayadi, Houda [Univ Lille Nord de France, 59000 Lille (France); Equipe Catalyse, UCEIV, E.A. 4492, MREI, ULCO, 59140 Dunkerque (France); Skaf, Mira [Univ Lille Nord de France, 59000 Lille (France); Equipe Catalyse, UCEIV, E.A. 4492, MREI, ULCO, 59140 Dunkerque (France); Department of Chemistry, University of Balamand, P.O. Box 100, Tripoli (Lebanon); Labaki, Madona; Cousin, Renaud; Abi-Aad, Edmond [Univ Lille Nord de France, 59000 Lille (France); Equipe Catalyse, UCEIV, E.A. 4492, MREI, ULCO, 59140 Dunkerque (France)


    Au/CeO{sub 2} solids with different gold contents were prepared using the impregnation method. Electron microscopy (SEM and TEM) studies indicated the formation of both nanoparticles and large gold particles on the surface of the ceria support. SEM and XRD analyses revealed that the number and size of large particles increases with the gold content in the solid. The XPS technique showed that 90% of the total gold is in the metallic form Au{sup 0} while the remaining 10% were cationic gold species Au{sup +}. These latter were formed following calcination under dry air at 400 Degree-Sign C and are located in the proximity of the O{sup 2-} and/or Cl{sup -} present on the support. These Au{sup +} species are present at the edge of gold particles and they were reduced into metallic gold when the solid was vacuum treated (5-7.10{sup -4} mbar) at 400 Degree-Sign C for 1 h. When air was adsorbed at room temperature on the latter vacuum treated solids, two EPR signals were obtained. The first one was assigned to O{sub 2}{sup -} species whereas attributing the second signal was difficult and required a more detailed investigation that will be presented in a forthcoming work. -- Highlights: Black-Right-Pointing-Pointer Au/CeO{sub 2} solids prepared by the impregnation method present Au particles ranging from 5 nm up to 600 nm. Black-Right-Pointing-Pointer The adsorption of air on Au/CeO{sub 2} to the formation of two different species. Black-Right-Pointing-Pointer The adsorption of air at room temperature leads to the formation of O{sub 2}{sup -}. Black-Right-Pointing-Pointer The adsorption of air at room temperature leads to another species which is not obtained when pure oxygen is adsorbed. Black-Right-Pointing-Pointer The Au/CeO{sub 2} solid is a potential candidate for DeNO{sub x} at room temperature.

  20. 14 CFR 33.71 - Lubrication system.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Lubrication system. 33.71 Section 33.71... STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.71 Lubrication system. (a) General. Each lubrication system must function properly in the flight attitudes and atmospheric...

  1. 14 CFR 33.39 - Lubrication system.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Lubrication system. 33.39 Section 33.39... STANDARDS: AIRCRAFT ENGINES Design and Construction; Reciprocating Aircraft Engines § 33.39 Lubrication system. (a) The lubrication system of the engine must be designed and constructed so that it...

  2. Laboratory services series: a lubrication program

    Bowen, H.B.; Miller, T.L.


    The diversity of equipment and operating conditions at a major national research and development laboratory requires a systematic, effective lubrication program. The various phases of this program and the techniques employed in formulating and administering this program are discussed under the following topics: Equipment Identification, Lubrication Requirements, Assortment of Lubricants, Personnel, and Scheduling.

  3. 7 CFR 2902.47 - Gear lubricants.


    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Gear lubricants. 2902.47 Section 2902.47 Agriculture... Gear lubricants. (a) Definition. Products, such as greases or oils, that are designed to reduce... qualifying biobased gear lubricants. By that date, Federal agencies that have the responsibility for...

  4. Lubricant test for punching and blanking

    Olsson, David Dam; Bay, Niels; Andreasen, Jan Lasson


    di $cult work piece materials like stainless steels.For this group of materials few alternatives exist as regards appropriate lubricants and many companies apply the environmentally hazardous chlorinated para $n oils in order to insure a uccessful production.In connection with development...... of alternative lubricants the present paper describes a new lubricant test for punching....

  5. SEACAS Theory Manuals: Part III. Finite Element Analysis in Nonlinear Solid Mechanics

    Laursen, T.A.; Attaway, S.W.; Zadoks, R.I.


    This report outlines the application of finite element methodology to large deformation solid mechanics problems, detailing also some of the key technological issues that effective finite element formulations must address. The presentation is organized into three major portions: first, a discussion of finite element discretization from the global point of view, emphasizing the relationship between a virtual work principle and the associated fully discrete system, second, a discussion of finite element technology, emphasizing the important theoretical and practical features associated with an individual finite element; and third, detailed description of specific elements that enjoy widespread use, providing some examples of the theoretical ideas already described. Descriptions of problem formulation in nonlinear solid mechanics, nonlinear continuum mechanics, and constitutive modeling are given in three companion reports.

  6. Solid-phase cloning for high-throughput assembly of single and multiple DNA parts

    Lundqvist, Magnus; Edfors, Fredrik; Sivertsson, Åsa


    We describe solid-phase cloning (SPC) for high-throughput assembly of expression plasmids. Our method allows PCR products to be put directly into a liquid handler for capture and purification using paramagnetic streptavidin beads and conversion into constructs by subsequent cloning reactions. We...... at an average success rate above 80%. We report on several applications for SPC and we suggest it to be particularly suitable for high-throughput efforts using laboratory workstations....

  7. Novel and Expanded Oncology Drug Approvals of 2016-PART 1: New Options in Solid Tumor Management.

    Knepper, Todd C; Saller, James; Walko, Christine M


    The nonradiologic medical management of solid tumors has evolved from the use of traditional cytotoxic agents to modern targeted therapies, monoclonal antibodies, and immunotherapies. Advances in the understanding of cancer biology and therapeutic strategies have resulted in increasing numbers of new drug applications and approvals. Consequently, practicing oncologists need to learn how the newly available agents function and what toxicities to watch for, as well as ways to optimize the use of both new drugs and previously approved drugs with new indications. In 2016, the US Food and Drug Administration approved three novel drugs for the treatment of solid malignancies-olaratumab in selected patients with soft-tissue sarcoma, atezolizumab for the treatment of bladder cancer, and rucaparib for the treatment of ovarian cancer; also in 2016, the use of previously approved anticancer agents (including atezolizumab) was expanded into 11 new patient populations. The diversity of options for patients is evident in the broad range of the 2016 approvals, which include immune checkpoint inhibitors, targeted therapies, monoclonal antibodies, and traditional cytotoxic agents. This article focuses on the new agents and indications that emerged in 2016 for solid tumor treatment. We review the drug indications, mechanisms of action, pivotal trial data, pertinent toxicities, use in special populations, and the appropriate clinical contexts for treatment planning.

  8. Part I: characterization of solid dispersions of nimodipine prepared by hot-melt extrusion.

    Zheng, Xin; Yang, Rui; Tang, Xing; Zheng, Liangyuan


    The purpose of this study was to prepare and characterize solid dispersions of nimodipine with hydroxypropyl methylcellulose (HPMC, Methocel E5), polyvinylpyrrolidone/vinyl acetate copolymer (PVP/VA, Plasdone S630), and ethyl acrylate, methyl methacrylate polymer (Eudragit EPO). The goal was to investigate whether the solid dispersion prepared by hot-melt extrusion can improve the dissolution rate of nimodipine. The dissolution results indicated that three polymers are suitable carriers to enhance the in vitro dissolution rate of nimodipine in pH 4.5 medium. The solubility research and solubility parameters calculation was corresponded with dissolution data. XRPD and DSC data showed that the crystallinity was not observed in hot-melt extrudates. NMD acted as a plasticizer for PVP/VA and EPO and was miscible with the polymers as well as 10% NMD-HPMC systems, because a single T(g) was observed in these extrudates. However, two T(g)s were observed in the 30 and 50% NMD-HPMC samples, indicating phase separation. The weakening and shift of the N-H stretching vibration of the secondary amine groups of nimodipine as determined by FT-IR proved hydrogen bonding between the drug and polymers in the solid dispersion.

  9. Use of Textured Surfaces to Mitigate Sliding Friction and Wear of Lubricated and Non-Lubricated Contacts

    Blau, Peter Julian [ORNL


    If properly employed, the placement of three-dimensional feature patterns, also referred to as textures, on relatively-moving, load-bearing surfaces can be beneficial to their friction and wear characteristics. For example, geometric patterns can function as lubricant supply channels or depressions in which to trap debris. They can also alter lubricant flow in a manner that produces thicker load-bearing films locally. Considering the area occupied by solid areas and spaces, textures also change the load distribution on surfaces. At least ten different attributes of textures can be specified, and their combinations offer wide latitude in surface engineering. By employing directional machining and grinding procedures, texturing has been used on bearings and seals for well over a half century, and the size scales of texturing vary widely. This report summarizes past work on the texturing of load-bearing surfaces, including past research on laser surface dimpling of ceramics done at ORNL. Textured surfaces generally show most pronounced effects when they are used in conformal or nearly conformal contacts, like that in face seals. Combining textures with other forms of surface modification and lubrication methods can offer additional benefits in surface engineering for tribology. As the literature and past work at ORNL shows, texturing does not always provide benefits. Rather, the selected pattern and arrangement of features must be matched to characteristics of the proposed application, bearing materials, and lubricants.

  10. Viscosity measurement in thin lubricant films using shear ultrasonic reflection

    S. Kasolang; Dwyer-Joyce, R.S.


    When a shear ultrasonic wave is incident on a solid and liquid boundary, the proportion that is reflected depends on the liquid viscosity. This is the basis for some instruments for on-line measurement of bulk liquid viscosity. In machine elements, the lubricant is usually present in a thin layer between two rubbing solid surfaces. The thin film has a different response to an ultrasonic shear wave than liquid in bulk. In this work, this response is investigated with the aim of measuring visco...

  11. A Fully-Coupled Approach for Modelling Plastic Deformation and Liquid Lubrication in Metal Forming

    Üstünyagiz, Esmeray; Christiansen, Peter; Nielsen, Chris Valentin


    This paper presents a new approach for combined modelling of plastic deformation andliquid lubrication in the contact interfaces between material and tooling in metal forming includingsituations where the lubricant is functioning as a pressure carrier. The approach is an alternative toconventional...... elements with fictitious small stiffness to physical modelling based on a fullycoupled procedure in which the lubricant flow and the plastic deformation of the metallic materialare solved simultaneously. The approach takes advantage of the intrinsic velocity-pressurecharacteristics of the finite element...... flow formulation which stands on the border line between fluidand solid mechanics and allows treating the lubricants as viscous incompressible (or nearlyincompressible) fluid and the metallic materials as non-Newtonian, high viscous, incompressiblefluids. The presentation is focused on the theoretical...

  12. A criterion for assessing homogeneity distribution in hyperspectral images. Part 2: application of homogeneity indices to solid pharmaceutical dosage forms.

    Rosas, Juan G; Blanco, Marcelo


    This article is the second of a series of two articles detailing the application of mixing index to assess homogeneity distribution in oral pharmaceutical solid dosage forms by image analysis. Chemical imaging (CI) is an emerging technique integrating conventional imaging and spectroscopic techniques with a view to obtaining spatial and spectral information from a sample. Near infrared chemical imaging (NIR-CI) has proved an excellent analytical tool for extracting high-quality information from sample surfaces. The primary objective of this second part was to demonstrate that the approach developed in the first part could be successfully applied to near infrared hyperspectral images of oral pharmaceutical solid dosage forms such as coated, uncoated and effervescent tablets, as well as to powder blends. To this end, we assessed a new criterion for establishing mixing homogeneity by using four different methods based on a three-dimensional (M×N×λ) data array of hyperspectral images (spectral standard deviations and correlation coefficients) or a two-dimensional (M×N) data array (concentration maps and binary images). The four methods were used applying macropixel analysis to the Poole (M(P)) and homogeneity (H%(Poole)) indices. Both indices proved useful for assessing the degree of homogeneity of pharmaceutical samples. The results testify that the proposed approach can be effectively used in the pharmaceutical industry, in the finished products (e.g., tablets) and in mixing unit operations for example, as a process analytical technology tool for the blending monitoring (see part 1).

  13. The Lubricity of Glycerol and its Solutions

    Sivebæk, Ion Marius; Jakobsen, J.


    Glycerol has been recognised as an excellent diesel fuel and lubricant. It is a liquid that can originate from the transesterification of plant oil that also results in plant oil metyl (or ethyl) ester (biodiesel). Machine elements lubricated by glycerol show very low friction, in fact lower than...... the one predicted by hydrodynamic lubrication calculations. Addition of water to glycerol lowers the friction but increases the wear. In the present paper the lubricity (boundary lubrication performance) of glycerol and its solutions with water, ethanol and methanol is investigated. Dilution of glycerol...

  14. Self lubrication of bitumen froth in pipelines

    Joseph, D.D. [Univ. of Minnesota, Minneapolis, MN (United States)


    In this paper I will review the main properties of water lubricated pipelines and explain some new features which have emerged from studies of self-lubrication of Syncrudes` bitumen froth. When heavy oils are lubricated with water, the water and oil are continuously injected into a pipeline and the water is stable when in a lubricating sheath around the oil core. In the case of bitumen froth obtained from the Alberta tar sands, the water is dispersed in the bitumen and it is liberated at the wall under shear; water injection is not necessary because the froth is self-lubricating.

  15. Review of LCA studies of solid waste management systems--part I: lessons learned and perspectives.

    Laurent, Alexis; Bakas, Ioannis; Clavreul, Julie; Bernstad, Anna; Niero, Monia; Gentil, Emmanuel; Hauschild, Michael Z; Christensen, Thomas H


    The continuously increasing solid waste generation worldwide calls for management strategies that integrate concerns for environmental sustainability. By quantifying environmental impacts of systems, life cycle assessment (LCA) is a tool, which can contribute to answer that call. But how, where and to which extent has it been applied to solid waste management systems (SWMSs) until now, and which lessons can be learnt from the findings of these LCA applications? To address these questions, we performed a critical review of 222 published LCA studies of SWMS. We first analysed the geographic distribution and found that the published studies have primarily been concentrated in Europe with little application in developing countries. In terms of technological coverage, they have largely overlooked application of LCA to waste prevention activities and to relevant waste types apart from household waste, e.g. construction and demolition waste. Waste management practitioners are thus encouraged to abridge these gaps in future applications of LCA. In addition to this contextual analysis, we also evaluated the findings of selected studies of good quality and found that there is little agreement in the conclusions among them. The strong dependence of each SWMS on local conditions, such as waste composition or energy system, prevents a meaningful generalisation of the LCA results as we find it in the waste hierarchy. We therefore recommend stakeholders in solid waste management to regard LCA as a tool, which, by its ability of capturing the local specific conditions in the modelling of environmental impacts and benefits of a SWMS, allows identifying critical problems and proposing improvement options adapted to the local specificities.

  16. Solid, shape recovered 'Bulk' nitinol: Part II-Mechanical properties

    Saigal, Anil, E-mail: [Department of Mechanical Engineering, Tufts University, Medford, MA 02155 (United States); Fonte, Matthew [Department of Mechanical Engineering, Tufts University, Medford, MA 02155 (United States)


    Highlights: {yields} Evaluate use of solid bulk Nitinol as a potential material for hip replacements. {yields} At 400 MPa, Nitinol has an endurance limit greater than 10 million cycles. {yields} Below 445 MPa [1 1 1] textured specimens last longer than [1 1 0] textured specimens. {yields} Above 445 MPa, it switches and both fail relatively quickly around 400,000 cycles. {yields} Impact toughness - Charpy: 4 ft-lbs {+-} 3%, CT: 20-31 MPa{radical}m. - Abstract: The use of Nitinol for medical purposes was first reported in the late 1960s. Today Nitinol is commonly used for the manufacture of stents, which are primarily used in peripheral and coronary bypass graft interventions. The application of NiTi in orthopedics is an exciting prospect but one that has yet to be realized. Nitinol's unique mechanical behavior is derived from the coordinated atomic movements manifesting in phase transformations from cubic austenite to monoclinic martensite. These phase transformations are solid-to-solid phase transformations that occur without diffusion or plasticity, potentially making them reversible. They involve changes in the crystalline structure that can be induced by changes in either temperature or stress. In addition to phase transformations, Nitinol's mechanical strength is strongly dependent on the alloy composition and the method in which the material is processed, i.e. rolled, drawn, extruded, or forged. The mechanical work, combined with the intermediate heat treatment steps, contribute to modify microstructure, transformation temperatures and mechanical properties. These manufacturing processing steps lead to texturing (crystallographic alignment) of the material. Alignment of the atomic planes from texture in the polycrystalline material have a marked influence on the mechanical properties by either limiting or promoting phase transformations and shape recovery strains. This paper focuses on the fatigue and fracture properties of Nitinol.

  17. Magnetically assisted gas-solid fluidization in a tapered vessel: Part Ⅰ. Magnetization-LAST mode

    Jordan Hristov


    This article presents further experimental results of the Magnetization-LAST mode in magnetically assisted gas-fluidized tapered beds, including external transverse magnetic field control of solid phase movement, central channel formation, spout depth and the pressure drop across the bed. Phase diagrams similar to those recently reported for the Magnetization-FIRST mode were also developed. Dimensional analysis based on "pressure transform" of the initial set of variables and involving the magnetic granular Bond number pertinent to particle aggregate formation was applied to develop the scaling relationships.

  18. Review of LCA studies of solid waste management systems – Part I: Lessons learned and perspectives

    Laurent, Alexis; Bakas, Ioannis; Clavreul, Julie


    , e.g. construction and demolition waste. Waste management practitioners are thus encouraged to abridge these gaps in future applications of LCA. In addition to this contextual analysis, we also evaluated the findings of selected studies of good quality and found that there is little agreement......The continuously increasing solid waste generation worldwide calls for management strategies that integrate concerns for environmental sustainability. By quantifying environmental impacts of systems, life cycle assessment (LCA) is a tool, which can contribute to answer that call. But how, where...

  19. Problems in Bearings and Lubrication


    avariety of devicessuch astelectric motors, fan heaters and hair dryers . Thesebearings are made of sinteaed metal and are impregnated with lubricating...structures, frictionless space-vehicle simulators, tumbling (ball) mills and for many types of machine tools and measuring equipment. Typically, the

  20. Biobased lubricants via ruthenium catalysis

    The development of effective lubricants from natural oils is an ongoing mission. A few of the efforts have led to some promise, but many others have led elsewhere. An alternative approach to the direct use of natural oils may be needed. The drop-in replacement strategy allows industry to utilize mon...

  1. Longevity Of Dry Film Lubricants

    Kannel, J. W.; Stockwell, R. D.


    Report describes evaluation of dry film lubricants candidate for use in rotary joints of proposed Space Station. Study included experiments and theoretical analyses focused on longevity of sputtered molybdenum disulfide films and ion-plated lead films under conditions partially simulating rolling contact.

  2. Green Lubricants for Metal Forming

    Bay, Niels


    The increasing focus on legislation towards diminishing the impact on working environment as well as external environment has driven efforts to develop new, environmentally benign lubricants for metal forming. The present paper gives an overview of these efforts to substitute environmentally haza...

  3. Vegetable oil basestocks for lubricants

    Garces, R.; Martinez-Force, E.; Salas, J.


    The use of vegetable biodegradable basestocks for lubricant oils present several advantages over the much more extended mineral bases. These advantages refer to biodegradability, a renewable feedstock of local production, lubricant and viscosity index and lower costs than synthetic lubricant bases. Despite these benefits, their use in industry and motor vehicles is not yet extensive due their lower stability and higher pour points. Vegetable oils are esters of fatty acids and glycerol, and their physicochemical properties rely mainly on the composition of their acyl moieties. Thus, to assure the maximum levels of stability while maintaining acceptable behavior at low temperatures, monounsaturated fatty acids are preferred for this purpose. The presence of natural antioxidants also improves the properties of these vegetable based stocks as lubricants. These oils usually require additives to improve their viscosity value, oxidative stability and properties at low temperatures. In the present work, the different sources of vegetable oils appropriate for biolubricant production were reviewed. Their properties and the future improvement of the oil bases, oil based stock production, uses and additives are discussed. (Author).

  4. Lubricant-coolant fluid for machining metals

    Berlin, A.A.; Epshtein, V.R.; Pastunov, V.A.; Sherle, A.I.; Shpin' kov, V.A.; Sladkova, T.A.


    For improving the antiwear and anticorrosion properties, the lubricant-coolant fluid (LCF) based on water, triethanolamine, and NaNO/sub 2/ contains additionally the sodium salt of an acid ester of maleic acid and substituted oligooxyethylenes (NMO) with the following proportions of the components: triethanolamine 0.3-0.5%, NaNO/sub 2/ 0.3-0.5%, NMO 0.5-2.0%, and water the remainder. In the case of using the proposed LCF on high-speed machine tools, it can contain additionally a foam suppressor in an amount of 0.005-0.1%. For preventing microbiological contamination of the LCF, bactericides of the type furacillin, formalin, vazin (transliteration), and others in an amount of 0.005-0.1% can be added to its composition. Introduction of the NMO additive ensures high wetting and lubricating characteristics in the LCF, which is characterized by stability during storage and service and good anticorrosion properties. Use of the proposed LCF makes it possible to increase the life of the cutting tool by a factor of 2.2 in machining Steel 40Kh and by a factor of 1.3 in machining corroding steel by comparison with the prototype; at the same time the service life of the LCF is increased twofold. The LCF can be used in machining parts of alloyed construction and corrosionresistant steels with cutting-edge and abrasive tools.

  5. Resettable regime of diesel lubrication

    Nechaev E. P.


    Full Text Available A new method of engine oil saturation by microelements has been presented in the paper; it has been tested on vessels of the fishing fleet and in conditions of prolonged operation in the coastal diesel-engine power plants. The paper considers the results of performance tests of the most common diesel power plants of 6ЧН 25/34 type with the tribochemical reductant oil (TRO apparatus providing tribochemical lubrication. During comparative trials of two diesels the samples of lubricating oil m-10B2 and m-10 have been periodically collected and subjected to spectral analysis. In the samples the number of the following key microelements has been determined: iron (Fe, aluminum (Al, zinc (Zn, sodium (Na, barium (Ba, calcium (Ca, tin (Sn, phosphorus (P, potassium (K, sulfur (S, chlorine (Cl, silicon (Si. During the operation the processes of microelements' extraction and destruction in diesel motor oils evaluated by the relevant coefficients have been clearly manifested. Analyzing the obtained experimental data it should be noted that in both experiments the total balance of the controlled 15 trace elements has been balanced and approached within 1640.5–1650.3 g/t. And the greater measure refers to conventional oil. Stabilization and improvement of physical and chemical properties of motor oil in operation of a diesel engine is possible from the authors' viewpoint only in the tribochemical lubrication mode using the TRO apparatus and created hydrodynamic module – dispersant. The past performance tests suggest the possibility of use as a lubricant the conventional (pure oil under actual operating conditions. When in the tribochemical mode of diesel engine lubrication it has been established that in conventional (pure oil the oily medium has been formed with a spectrum of microelements equivalent to engine oil filler.

  6. Rheology and tribology of lubricants with polymeric viscosity modifiers

    Babak, LotfizadehDehkordi

    Elastohydrodynamic lubrication (EHL) theory has been used to model the lubrication state of antifriction machine elements, where initial viscosity and pressure viscosity coefficients are essential parameters in film thickness modeling. Since the pressures of lubricants in the contact zone can be very high, it is important to know the rheological properties of lubricants in these pressure and temperature regimes. The characteristics of viscosity behavior as a function of pressure are also essential for a universal definition of the pressure viscosity coefficient in order to estimate film thickness in an EHL regime. In this study, viscosities and pressure-viscosity coefficients of ten commercial engine and gear oils and seventeen laboratory-produced oil/polymer viscosity modifiers (VM) additives are measured up to 1.3 GPa at 40, 75 and 100 °C. For the first time, a sharp increase in the viscosity and piezoviscous factor is observed in both mineral-based and synthetic-based oils with different VMs. Analysis of the experimental results indicates that sharp increase in viscosity observed in these experiments are believed to arise from physical changes in the VMs, that is liquid-solid phase transition. Evidence is offered that polymer properties such as molecular weight, concentration and structure influence the onset of the phase transitions. A modified Yasutomi model, which normally describes the pressure dependence of the viscosity of lubricants very well, fails to predict the viscosity of the specimens above the onset of sharp increase in viscosity. A design of experiment (DOE) analysis using Design-Expert software indicates that pressure and temperature are the most critical parameters in the viscosity variation. Tribological tests demonstrate that wear in the contact, zone occurs at temperatures and stresses that coincides with the VM phase transitions in both commercial and laboratory synthesized oil/VMs. Tribological results also indicate that the onset of the

  7. High repetition ration solid state switched CO2 TEA laser employed in industrial ultrasonic testing of aircraft parts

    von Bergmann, Hubertus; Morkel, Francois; Stehmann, Timo


    Laser Ultrasonic Testing (UT) is an important technique for the non-destructive inspection of composite parts in the aerospace industry. In laser UT a high power, short pulse probe laser is scanned across the material surface, generating ultrasound waves which can be detected by a second low power laser system and are used to draw a defect map of the part. We report on the design and testing of a transversely excited atmospheric pressure (TEA) CO2 laser system specifically optimised for laser UT. The laser is excited by a novel solid-state switched pulsing system and utilises either spark or corona preionisation. It provides short output pulses of less than 100 ns at repetition rates of up to 1 kHz, optimised for efficient ultrasonic wave generation. The system has been designed for highly reliable operation under industrial conditions and a long term test with total pulse counts in excess of 5 billion laser pulses is reported.

  8. Load-Induced Confinement Activates Diamond Lubrication by Water

    Zilibotti, G.; Corni, S.; Righi, M. C.


    Tribochemical reactions are chemical processes, usually involving lubricant or environment molecules, activated at the interface between two solids in relative motion. They are difficult to be monitored in situ, which leaves a gap in the atomistic understanding required for their control. Here we report the real-time atomistic description of the tribochemical reactions occurring at the interface between two diamond films in relative motion, by means of large scale ab initio molecular dynamics. We show that the load-induced confinement is able to catalyze diamond passivation by water dissociative adsorption. Such passivation decreases the energy of the contacting surfaces and increases their electronic repulsion. At sufficiently high coverages, the latter prevents surface sealing, thus lowering friction. Our findings elucidate effects of the nanoscale confinement on reaction kinetics and surface thermodynamics, which are important for the design of new lubricants.

  9. Study on the lubrication properties of biodiesel as fuel lubricity enhancers

    Jianbo Hu; Zexue Du; Changxiu Li; Enze Min [Research Institute of Petroleum Processing, SINOPEC, Beijing (China)


    Unrefined biodiesels containing small quantities of monoglycerides, diglycerides, and triglycerides, and refined biodiesels not containing these glycerides were added to diesel fuel and the resulting lubricity was measured using the High Frequency Reciprocating Rig (HFRR) method. The unrefined biodiesels showed higher lubricity properties than refined biodiesels. The chemical factors influencing the lubricity properties of biodiesels were investigated. Methyl esters and monoglycerides are the main compositions that determine the lubricity of biodiesels that meet international standards. Free fatty acids and diglycerides can also affect the lubricity of biodiesel, but not so much as monoglycerides. Triglycerides almost have no effects on the lubricity of biodiesel. 18 refs., 3 figs., 5 tabs.

  10. Process for producing biodiesel, lubricants, and fuel and lubricant additives in a critical fluid medium

    Ginosar, Daniel M.; Fox, Robert V.


    A process for producing alkyl esters useful in biofuels and lubricants by transesterifying glyceride- or esterifying free fatty acid-containing substances in a single critical phase medium is disclosed. The critical phase medium provides increased reaction rates, decreases the loss of catalyst or catalyst activity and improves the overall yield of desired product. The process involves the steps of dissolving an input glyceride- or free fatty acid-containing substance with an alcohol or water into a critical fluid medium; reacting the glyceride- or free fatty acid-containing substance with the alcohol or water input over either a solid or liquid acidic or basic catalyst and sequentially separating the products from each other and from the critical fluid medium, which critical fluid medium can then be recycled back in the process. The process significantly reduces the cost of producing additives or alternatives to automotive fuels and lubricants utilizing inexpensive glyceride- or free fatty acid-containing substances, such as animal fats, vegetable oils, rendered fats, and restaurant grease.

  11. Identifying lubricant options for compressor bearing designs

    Karnaz, J.; Seeton, C.; Dixon, L.


    Today’s refrigeration and air conditioning market is not only driven by the environmental aspects of the refrigerants, but also by the energy efficiency and reliability of system operation. Numerous types of compressor designs are used in refrigeration and air conditioning applications which means that different bearings are used; and in some cases, multiple bearing types within a single compressor. Since only one lubricant is used, it is important to try to optimize the lubricant to meet the various demands and requirements for operation. This optimization entails investigating different types of lubricant chemistries, viscosities, and various formulation options. What makes evaluating these options more challenging is the refrigerant which changes the properties of the lubricant delivered to the bearing. Once the lubricant and refrigerant interaction are understood, through various test methods, then work can start on collaborating with compressor engineers on identifying the lubricant chemistry and formulation options. These interaction properties are important to the design engineer to make decisions on the adequacy of the lubricant before compressor tests are started. This paper will discuss the process to evaluate lubricants for various types of compressors and bearing design with focus on what’s needed for current refrigerant trends. In addition, the paper will show how the lubricant chemistry choice can be manipulated through understanding of the bearing design and knowledge of interaction with the refrigerant to maximize performance. Emphasis will be placed on evaluation of synthetic lubricants for both natural and synthetic low GWP refrigerants.

  12. Testing of nuclear grade lubricants and their effects on A540 B24 and A193 B7 bolting materials

    Czajkowski, C.J.


    An investigation was performed on eleven commonly used lubricants by the nuclear power industry. The investigation included EDS analysis of the lubricants, notched-tensile constant extension rate testing of bolting materials with the lubricants, frictional testing of the lubricants and weight loss testing of a bonded solid film lubricant. The report generally concludes that there is a significant amount of variance in the mechanical properties of common bolting materials; that MoS/sub 2/ can hydrolyze to form H/sub 2/S at 100/sup 0/C and cause stress corrosion cracking (SCC) of bolting materials, and that the use of copper-containing lubricants can be potentially detrimental to high strength steels in an aqueous environment. Additionally, the testing of various lubricants disclosed that some lubricants contain potentially detrimental elements (e.g. S, Sb) which can promote SCC of the common bolting materials. One of the most significant findings of this report is the observation that both A193 B7 and A540 B24 bolting materials are susceptible to transgranular stress corrosion cracking in demineralized H/sub 2/O at 280/sup 0/C in notched tensile tests.

  13. Review of the micro-tubular solid oxide fuel cell. Part I. Stack design issues and research activities

    Lawlor, V.; Griesser, S.; Buchinger, G.; Olabi, A. G.; Cordiner, S.; Meissner, D.

    Fuel cells are devices that convert chemical energy in hydrogen enriched fuels into electricity electrochemically. Micro-tubular solid oxide fuel cells (MT-SOFCs), the type pioneered by K. Kendall in the early 1990s, are a variety of SOFCs that are on the scale of millimetres compared to their much larger SOFC relatives that are typically on the scale of tens of centimetres. The main advantage of the MT-SOFC, over its larger predecessor, is that it is smaller in size and is more suitable for rapid start up. This may allow the SOFC to be used in devices such as auxiliary power units, automotive power supplies, mobile electricity generators and battery re-chargers. The following paper is Part I of a two part series. Part I will introduce the reader to the MT-SOFC stack and its applications, indicating who is researching what in this field and also specifically investigate the design issues related to multi-cell reactor systems called stacks. Part II will review in detail the combinations of materials and methods used to produce the electrodes and electrolytes of MT-SOFC's. Also the role of modelling and validation techniques used in the design and improvement of the electrodes and electrolytes will be investigated. A broad range of scientific and engineering disciplines are involved in a stack design. Scientific and engineering content has been discussed in the areas of thermal-self-sustainability and efficiency, sealing technologies, manifold design, electrical connections and cell performance optimisation.

  14. Potential of Power Generation from Biogas. Part II: Municipal Solid Waste

    Vera-Romero Iván


    Full Text Available The objective of this work is to estimate the amount of biogas that could be obtained from the anaerobic decomposition of the organic fraction of the municipal solid waste (MSW disposed in a sanitary landfill, by capturing and taking advantage of it to generate electricity which can be consumed by Ciénega Region of Chapala in the state of Michoacán, México. To estimate the biogas captured, the Mexican Model of Biogas version 2.0 was used; capturing MSW for 11 years with a project life of 21 years. For the analysis of power generation an average cost for schedule rate 5-A from the CFE for public service was used. Four possible scenarios were evaluated: optimal, intermediate optimal, intermediate pessimistic and pessimistic; varying characteristics such as adequate handling site, fire presence, coverage, leachate, among others. Each of the scenarios, economically justify the construction of an inter-municipal landfill obtaining substantial long-term economic benefits. (26.5×106 USD, 22.8×106 , 17.9×106 and 11.7×106 respectively, while contributing to climate change mitigation and prevention of diseases.

  15. The impact of coulombic interactions among polar molecules and metal substrates on flow and lubrication properties

    Gkagkas, K.; Ponnuchamy, V.


    In the current work we present an extensive study on the impact of short- and long-range interactions between solids and liquids on the hydrodynamic and lubrication behaviour of a tribological system. We have implemented a coarse grain molecular dynamics description of two ionic liquids (ILs) as lubricants which are confined by two infinitely long flat iron solids and which are subjected to a shearing flow. The impact of surface polarizability and molecule geometry on the ion arrangement under shearing has been studied in detail. The results have revealed two regimes of lubrication, with a liquid phase being present under low normal loads, while solidification of the ILs, accompanied by a steep rise of normal forces and significant wall slip is observed at small plate-to-plate distances.




    Increased thermal efficiency, savings in the fuel consumption and the possibility to burn low quality fuels conducted to an intense development of marine engines in past 20 years, this progress being emphasized by the increased combustion pressures and better combustion properties. These improvements represent a continuous challenge for lubricating oil manufacturers: the rise in combustion temperatures and pressures is making difficult to preserve the oil film in critical area...

  17. The Lubrication Qualities of Dimethyl Ether (DME)

    Sivebæk, Ion Marius; Sorenson, Spencer C; Jakobsen, J.


    recycling. A significant problem arises when conventional injection equipment is used for pumping DME: It breaks down prematurely due to the poor lubrication qualities of DME compared to those of diesel oil. These qualities consist of the lubricity, which is important in the boundary lubrication regime......, and the viscosity, which plays a major role in the hydrodynamic lubrication regime. The lubricity of DME has been established by the medium frequency pressurised reciprocating rig (MFPRR) to be very low compared to the one of diesel oil. But the DME film limits the wear extent significantly compared to the case...... of dry sliding. By mixing DME with additives, the lubricity level is easily raised even above the one of diesel oil. The viscosity of DME has been established by the volatile fuel viscometer (VFVM) to be as low as 0.185 cSt @ 25 oC. It is also shown that this viscosity cannot be raised significantly...

  18. Measurement of Lubricating Condition between Swashplate and Shoe in Swashplate Compressors under Practical Operating Conditions

    Suzuki, Hisashi; Fukuta, Mitsuhiro; Yanagisawa, Tadashi

    In this paper, lubricating conditions between a swashplate and a shoe in a swashplate compressor for automotive air conditioners is investigated experimentally. The conditions are measured with an electric resistance method that utilizes the swash plate and the shoe as electrodes respectively. The instrumented compressor is connected to an experimental cycle with R134a and operated under various operating conditions of pressure and rotational speed. An improved measurement technique and applying a solid contact ratio to the measurement results permit to measure the lubricating condition at high rotational speed (more than 8000 rpm) and to predic an occurrence of scuffing between the swashplate and the shoe, and therefore enables a detailed study of lubricating characteristics. It is shown by the measurement that the voltage of the contact signal decreases, which means better lubricating condition, with the decrease of the compression pressure and with the increase of the rotational speed from 1000 rpm through 5000 rpm. The lubricating condition tends to worsen at more than 5000 rpm. Furthermore, it is confirmed that the lubricating condition under transient operation is worse obviously as compared with that under steady-state operation.

  19. High temperature solid oxide fuel cell integrated with novel allothermal biomass gasification. Part I: Modelling and feasibility study

    Panopoulos, K. D.; Fryda, L. E.; Karl, J.; Poulou, S.; Kakaras, E.

    Biomass gasification derived fuel gas is a renewable fuel that can be used by high temperature fuel cells. In this two-part work an attempt is made to investigate the integration of a near atmospheric pressure solid oxide fuel cell (SOFC) with a novel allothermal biomass steam gasification process into a combined heat and power (CHP) system of less than MW e nominal output range. Heat for steam gasification is supplied from SOFC depleted fuel into a fluidised bed combustor via high temperature sodium heat pipes. The integrated system model was built in Aspen Plus™ simulation software and is described in detail. Part I investigates the feasibility and critical aspects of the system based on modelling results. A low gasification steam to biomass ratio (STBR = 0.6) is used to avoid excess heat demands and to allow effective H 2S high temperature removal. Water vapour is added prior to the anode to avoid carbon deposition. The SOFC off gases adequately provide gasification heat when fuel utilisation factors are f = 0.7 and current density 2500 A m -2 the electrical efficiency is estimated at 36% while thermal efficiency at 14%. An exergy analysis is presented in Part II.

  20. Lubrication performance and mechanisms of Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxide nanoparticles as lubricant additives

    Li, Shuo; Bhushan, Bharat


    Solid lubricant particles are commonly used as oil additives for low friction and wear. Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxides (LDH) were synthesized by coprecipitation method. The benefits of LDH nanoparticles are that they can be synthesized using chemical methods where size and shape can be controlled, and can be modified organically to allow dispersal in fluids. The LDH nanoparticles were characterized by X-ray diffraction, scanning electron microscope, thermogravimetry, and differential scanning calorimetry. A pin-on-disk friction and wear tester was used for evaluating the friction and wear properties of LDH nanoparticles as lubricant additives. LDH nanoparticles have friction-reducing and anti-wear properties compared to oil without LDHs. Mg/Al-LDH has the best lubrication, possibly due to better thermal stability in severe conditions.

  1. Influence of Lubricant Pocket Geometry upon Lubrication Mechanisms on Tool-Workpiece Interfaces in Metal Forming

    Shimizu, I; Martins, P.A.F.; Bay, Niels


    Micro lubricant pockets located on the surface of plastically deforming workpieces are recognized to improve the performance of fluid lubrication in a metal forming processes. This work investigates the joint influence of pocket geometry and process working conditions on micro lubrication mechani...

  2. Lubrication from mixture of boric acid with oils and greases

    Erdemir, Ali


    Lubricating compositions including crystalline boric acid and a base lubricant selected from oils, greases and the like. The lubricity of conventional oils and greases can also be improved by adding concentrates of boric acid.

  3. Lubrication System with Tolerance for Reduced Gravity

    Portlock, Lawrence E. (Inventor); McCune, Michael E. (Inventor); Dobek, Louis J. (Inventor)


    A lubrication system includes an auxiliary lubricant tank 48, a supply conduit 58 extending from a source of lubricant 26 to the auxiliary lubricant tank. A reduced-G bypass line 108 branches from the conduit and enters the auxiliary tank at a first elevation E.sub.1. The system also includes an auxiliary tank discharge conduit 116, a portion of which resides within the tank. The resident portion has an opening 122 at least partially at a second elevation E.sub.2 higher than the first elevation.

  4. A new lubricant carrier for metal forming

    Arentoft, Mogens; Bay, Niels; Tang, Peter Torben


    A lubricant carrier for metal forming processes is developed. Surfaces with pores of micrometer size for entrapping lubricant are generated by electrochemical deposition of an alloy, consisting of two immiscible metals, of which one metal subsequently is etched away leaving 5 mu m layers with a s......A lubricant carrier for metal forming processes is developed. Surfaces with pores of micrometer size for entrapping lubricant are generated by electrochemical deposition of an alloy, consisting of two immiscible metals, of which one metal subsequently is etched away leaving 5 mu m layers...


    WANG Weizu; HUANG Ping


    The acid number of the mixed solution of 150SN oil and oleic acid characterizes the volume content of oleic acid in the solution, based on which the adsorptive capability of oleic acid is studied on the 45 steel balls and disks. Boundary lubrication tests are carried out on a self designed ball-on-disk machine. The base oil is pure 150SN oil, and oleic acid as additive are added into the lubricant. Disks have surface roughness values (Ra) of 0.8 μm and 0.4 μm. The electrical contact resistance method is used to determine the lubrication status. Hypothesize that the molecular film is monomolecular layer in condensed state and the opposing surfaces are completely separated by molecular film. A boundary lubrication model is established according to experimental results and hypothesizes. The experimental and calculational results show that the adsorption of polar molecules on steel surface is the main factor to form the boundary lubrication film. Load and sliding speed contribute little to the friction coefficient of boundary lubrication. The properties of steel surface and additive for the lubricant significantly influence on the characters of boundary lubrication. The smaller the surface roughness value is, the smaller the friction coefficient of the boundary lubrication is.

  6. Measurement of trace elements in lubricating oils by the PIXE method

    Jaskola, M.; Kucharski, M.; Zemlo, L. (Institute of Nuclear Research, Warsaw (Poland)); Babinski, B. (Wojskowy Instytut Techniki Pancernej i Samochodowej, Warszawa (Poland))


    A beam of 2 to 2.5 MeV protons has been used to excite X-ray emission from a lubricating oil sample. The X-rays have been detected using a Si(Li) solid state detector. The experimental arrangement for the PIXE method is also described.

  7. Strip reduction testing of lubricants developed during ENFORM project

    Gazvoda, S.; Andreasen, Jan Lasson; Olsson, David Dam

    Strip reduction testing of lubricants developed during ENFORM project. Experiments were conducted with the strip reduction test [1] in order to classify experimental lubricants, developed during concerned project. One reference lubricant was used during testing.......Strip reduction testing of lubricants developed during ENFORM project. Experiments were conducted with the strip reduction test [1] in order to classify experimental lubricants, developed during concerned project. One reference lubricant was used during testing....

  8. Tribological Performance of Ni3Al Matrix Self-Lubricating Composites Containing Multilayer Graphene and Ti3SiC2 at Elevated Temperatures

    Yan, Zhao; Shi, Xiaoliang; Huang, Yuchun; Deng, Xiaobin; Yang, Kang; Liu, Xiyao


    The application of Ni3Al-based alloy (NA) in the field of aerospace was limited by its poor tribological properties. For improving the tribological performance of NA, multilayer graphene (MLG) and Ti3SiC2 were added in Ni3Al matrix composites. Tribological behavior of Ni3Al matrix composites containing 1.5 wt.% MLG and 10 wt.% Ti3SiC2 (NMT) against Si3N4 ball at 12 N-0.2 m/s from 25 to 750 °C was investigated. The results showed that NMT exhibited the excellent tribological behavior [lower friction coefficients (0.26-0.57) and less wear resistance (3.1-6.5 × 10-6 mm3 N-1 m-1)] due to synergetic effect of MLG and Ti3SiC2 over a wide temperature range from 25 to 750 °C. At 25-350 °C, part of MLG enriched on worn surface could play a role in reducing friction and improving wear resistance. At 350-550 °C, although MLG gradually lost the lubricating properties, the partial decomposition of Ti3SiC2 could continually improve the tribological properties of NMT. At 550-750 °C, Ti3SiC2 on worn surface was oxidized to form lubricating film, while Ti3SiC2 in the subsurface played an important role in supporting the film, resulting in the excellent high-temperature tribological performance. The research had good guiding significance for the preparation of wide temperature range self-lubricating material and the study of synergetic effect of complex solid lubricants.

  9. Novel spraying apparatus to investigate the lubricant deposition on metal sheets at high temperature

    Medea, Francesco; Ghiotti, Andrea; Bruschi, Stefania; Bellin, Marco


    The constant demand of increasing performances and safety in automotive industry has led significant innovations in the materials as well as in forming processes. In particular, lightweight aluminium alloys are knowing higher and higher importance, thanks to the development of new stamping processes at high temperatures capable to allow improved formability, low spring-back and accurate micro-structural control in the formed parts. However, the choice of proper process parameters, in terms of lubrication at the interfaces between the dies and the blank, still represents a critical point for the process feasibility. On this basis, the paper aims at presenting a novel spraying apparatus to investigate the deposition of lubricants in hot stamping. The equipment allows the accurate control of the quantity of the lubricant that is deposited on the specimen and of the deposition temperature to maximize the lubricant adhesion. The results show the capability of the new equipment and the good stability of the conditions during testing.

  10. Supramolecular ionogel lubricants with imidazolium-based ionic liquids bearing the urea group as gelator.

    Yu, Qiangliang; Wu, Yang; Li, DongMei; Cai, Meirong; Zhou, Feng; Liu, Weimin


    A new class of ionic liquid gels (ionogels) is prepared through the supramolecular self-assembly of imidazolium-based ionic liquids (ILs) bearing the urea group as gelators in normal ILs. The ILs gelator can self-assemble through hydrogen bonding and hydrophobic interaction to form analogous lamellar structures and solidify base ILs. The obtained ionogels exhibit superior anticorrosion and conductivity characteristics. Moreover, ionogels show fully thermoreversible and favorable thixotropic characteristics, such that they can be used as high-performance semisolid conductive lubricants. The tribological tests reveal that these ionogels lubricants can effectively reduce the friction of sliding pairs effectively and have better tribological performance than the pure ILs under harsh conditions. Ionogel lubricants not only maintain the excellent tribological properties and conductivity of ILs, but also prevent base liquids from creeping and leakage. Therefore, ionogel lubricants can be potentially used in the conductive parts of electrical equipments.

  11. Linear polymer aqueous solutions in soft lubrication:From boundary to mixed lubrication

    LIU; ShuHai; TAN; GuiBin; WANG; DeGuo


    In order to better understand linear polymer aqueous solutions in soft lubrication from boundary to mixed lubrication,poly(ethylene glycol) and sodium hyaluronateare used as model polymers were investigated by using UMT-2 tribometer with the ball-on-disk mode. The relationship between the master Stribeck curves of the polymer aqueous solutions and the influence factors were investigated. Experimental results indicated that soft lubrication is determined by lubricant rheological properties and surface-lubricant interactions, e.g., wetting behavior of polymer aqueous solution on tribological surfaces.




    We became the acknowledged world leaders in the science fundamentals of the technology of water lubricated pipelines focusing on stability, numerical and experimental studies. We completed the first direct numerical simulation of axisymmetric core flow. We showed that the pressure at the front of the wave is large (the fluid enters a converging region) and it pushes the interface in, steepening the wave at its front. At the backside of the wave, behind the crest, the pressure is low (diverging flow) and it pulls the interface to the wall, smoothing the backside of the wave. The steepening of the wave can be regarded as a shock up by inertia and it shows that dynamics works against the formation of long waves which are often assumed but not justified in the analysis of such problems. We showed that the steep wave persists even as the gap between the core and the wall decreases to zero. The wave length also decreases in proportion, so that the wave shape is preserved in this limit. This leads to the first mathematical solution giving rise sharkskin. The analysis also showed that there is a threshold Reynolds number below which the total force reckoned relative to a zero at the wave crest is negative, positive above, and we conjectured, therefore that inertia is required to center a density matched core and to levitate the core off the wall when the density is not matched. Other work relates to self-lubricated transport of bitumen froth and self-lubricated transport of bitumen froth.

  13. Lubrication at physiological pressures by polyzwitterionic brushes.

    Chen, Meng; Briscoe, Wuge H; Armes, Steven P; Klein, Jacob


    The very low sliding friction at natural synovial joints, which have friction coefficients of mu lubrication is attributed primarily to the strong hydration of the phosphorylcholine-like monomers that make up the robustly attached brushes, and may have relevance to a wide range of human-made aqueous lubrication situations.

  14. 30 CFR 56.14204 - Machinery lubrication.


    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Machinery lubrication. 56.14204 Section 56.14204 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Equipment Safety Practices and Operational Procedures § 56.14204 Machinery lubrication. Machinery...

  15. 30 CFR 57.14204 - Machinery lubrication.


    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Machinery lubrication. 57.14204 Section 57.14204 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Equipment Safety Practices and Operational Procedures § 57.14204 Machinery lubrication. Machinery...

  16. 49 CFR 396.5 - Lubrication.


    ... 49 Transportation 5 2010-10-01 2010-10-01 false Lubrication. 396.5 Section 396.5 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION... § 396.5 Lubrication. Every motor carrier shall ensure that each motor vehicle subject to its control...

  17. A cartilage-inspired lubrication system.

    Greene, George W; Olszewska, Anna; Osterberg, Monika; Zhu, Haijin; Horn, Roger


    Articular cartilage is an example of a highly efficacious water-based, natural lubrication system that is optimized to provide low friction and wear protection at both low and high loads and sliding velocities. One of the secrets of cartilage's superior tribology comes from a unique, multimodal lubrication strategy consisting of both a fluid pressurization mediated lubrication mechanism and a boundary lubrication mechanism supported by surface bound macromolecules. Using a reconstituted network of highly interconnected cellulose fibers and simple modification through the immobilization of polyelectrolytes, we have recreated many of the mechanical and chemical properties of cartilage and the cartilage lubrication system to produce a purely synthetic material system that exhibits some of the same lubrication mechanisms, time dependent friction response, and high wear resistance as natural cartilage tissue. Friction and wear studies demonstrate how the properties of the cellulose fiber network can be used to control and optimize the lubrication and wear resistance of the material surfaces and highlight what key features of cartilage should be duplicated in order to produce a cartilage-mimetic lubrication system.

  18. Lubricity characteristics of marine distillate fuels

    Crutchley, Ian [Innospec Fuel Specialties, Ellesmere Port (United Kingdom); Green, Michael [Intertek Lintec ShipCare Services, Darlington (United Kingdom)


    This article from Innospec Fuel Specialties, Ellesmere Port, UK, and Intertek Lintec ShipCare Services, Darlington, UK, examines the lubricity characteristics of marine distillate fuels available today in relation to the requirements and limits imposed in ISO8217:2010. It will estimate expected failure rates and also asses the perceived relationship between lubricity, sulphur content and viscosity. (orig.)

  19. Biobased, environmentally friendly lubricants for processing plants

    Vegetable oil based lubricants have excellent lubricity, biodegradability, good viscosity temperature characteristics and low evaporation loss, but poor thermos-oxidative stability and cold flow properties. This paper presents a systematic approach to improve the oxidative and cold flow behavior of...

  20. Pressure-viscosity coefficient of biobased lubricants

    Film thickness is an important tribological property that is dependent on the combined effect of lubricant properties, material property of friction surfaces, and the operating conditions of the tribological process. Pressure-viscosity coefficient (PVC) is one of the lubricant properties that influe...

  1. Turbulence Models of Hydrodynamic Lubrication

    张直明; 王小静; 孙美丽


    The main theoretical turbulence models for application to hydrodynamic lubrication problems were briefly reviewed, and the course of their development and their fundamentals were explained. Predictions by these models on flow fields in turbulent Couette flows and shear-induced countercurrent flows were compared to existing measurements, and Zhang & Zhang' s combined k-ε model was shown to have surpassingly satisfactory results. The method of application of this combined k-ε model to high speed journal bearings and annular seals was summarized, and the predicted results were shown to be satisfactory by comparisons with existing experiments of journal bearings and annular seals.

  2. Mechanism and characters of thin film lubrication at nanometer scale

    雒建斌; 温诗铸


    Thin film lubrication is a transition region between elastohydrodynamic lubrication and boundary lubrication, A technique of relative optical interference intensity with the resolution of 0.5 nm in the vertical direction and 1.5 nm in the horizontal direction is used in a pure rolling process to measure the film thickness with different lubricants, speeds, loads and substrate surface energy. Experimental data show that the characteristics of thin film lubrication are different from those of elastohydrodynamic lubrication and boundary lubrication. As the rolling speed decreases, a critical film thickness can be found to distinguish thin film lubrication from elastohydrodynamic lubrication. Such thickness is related to the substrate surface energy, atmospheric viscosity of lubricant, etc. A physical model of thin film lubrication with the fluid layer, the ordered liquid layer and the adsorbed layer is proposed and the functions of these different layers are discussed.

  3. 基于SolidWorks的冲压件结构优化%Optimum Structural Design of Punched Parts Based on SolidWorks

    梁国一; 卢军



  4. Biodegradation and toxicological evaluation of lubricant oils

    Ivo Shodji Tamada


    Full Text Available The aim of this work was to compare different toxicity levels of lubricant oils. The tests were performed using the earthworm (Eisenia andrei, arugula seeds (Eruca sativa and lettuce seeds (Lactuca sativa, with three types of contaminants (mineral lubricant oil, synthetic lubricant oil and used lubricant oil for various biodegradation periods in the soil. The toxicity tests indirectly measured the biodegradation of the contaminants. The samples were analyzed at t0, t60, t120 and t180 days of biodegradation. The used lubricant oil was proved very toxic in all the tests and even after biodegradation its toxicity was high. The mineral and synthetic oils were biodegraded efficiently in the soil although their toxicity did not disappear completely after 180 days.

  5. Double hollow MoS2 nano-spheres: Synthesis, tribological properties, and functional conversion from lubrication to photocatalysis

    Liu, Yueru; Hu, Kunhong; Hu, Enzhu; Guo, Jianhua; Han, Chengliang; Hu, Xianguo


    Molybdenum disulfide (MoS2) has extensive applications in industries as solid lubricants and catalysts. To improve the lubricating performance of MoS2, novel double-hollow-sphere MoS2 (DHSM) nanoparticles with an average diameter of approximately 90 nm were synthesized on sericite mica (SM). When the DHSM/SM composite was used as an additive in polyalphaolefin oil, friction and wear decreased by 22.4% and 63.5% respectively. The low friction and wear were attributed to the easy exfoliation of DHSM. The DHSM/SM composite was then rubbed under 40 MPa for 1 h to investigate the exfoliation and functional conversion behaviors of DHSM. Results showed that DHSM (lubricating structure) on SM could be completely exfoliated into nanosheets (catalytic structure) by rubbing. The nanosheets exfoliated from DHSM presented good photocatalytic activity for the removal of organic compounds from waste water. This work provided both a novel solid lubricant for industrial applications and a possible approach to designing a novel green lubricant for use as a photocatalyst in organic-waste treatment after lubricating service life.

  6. Structured free-water clusters near lubricating surfaces are essential in water-based lubrication.

    Hou, Jiapeng; Veeregowda, Deepak H; de Vries, Joop; Van der Mei, Henny C; Busscher, Henk J


    Water-based lubrication provides cheap and environmentally friendly lubrication and, although hydrophilic surfaces are preferred in water-based lubrication, often lubricating surfaces do not retain water molecules during shear. We show here that hydrophilic (42° water contact angle) quartz surfaces facilitate water-based lubrication to the same extent as more hydrophobic Si crystal surfaces (61°), while lubrication by hydrophilic Ge crystal surfaces (44°) is best. Thus surface hydrophilicity is not sufficient for water-based lubrication. Surface-thermodynamic analyses demonstrated that all surfaces, regardless of their water-based lubrication, were predominantly electron donating, implying water binding with their hydrogen groups. X-ray photoelectron spectroscopy showed that Ge crystal surfaces providing optimal lubrication consisted of a mixture of -O and =O functionalities, while Si crystal and quartz surfaces solely possessed -O functionalities. Comparison of infrared absorption bands of the crystals in water indicated fewer bound-water layers on hydrophilic Ge than on hydrophobic Si crystal surfaces, while absorption bands for free water on the Ge crystal surface indicated a much more pronounced presence of structured, free-water clusters near the Ge crystal than near Si crystal surfaces. Accordingly, we conclude that the presence of structured, free-water clusters is essential for water-based lubrication. The prevalence of structured water clusters can be regulated by adjusting the ratio between surface electron-donating and electron-accepting groups and between -O and =O functionalities.

  7. Surface functionalization by fine ultraviolet-patterning of nanometer-thick liquid lubricant films

    Lu, Renguo [Department of Complex Systems Science, Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Zhang, Hedong, E-mail: [Department of Complex Systems Science, Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Komada, Suguru [Department of Micro-Nano System Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Mitsuya, Yasunaga [Nagoya Industrial Science Research Institute, Noa Yotsuya Building 2F, 1-13, Yotsuya-Douri, Chikusa-ku, Nagoya 464-0819 (Japan); Fukuzawa, Kenji; Itoh, Shintaro [Department of Micro-Nano System Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)


    Highlights: • We present fine UV-patterning of nm-thick liquid films for surface functionalization. • The patterned films exhibit both a morphological pattern and a functional pattern of different surface properties. • The finest pattern linewidth was 0.5 μm. • Fine patterning is crucial for improving surface and tribological properties. - Abstract: For micro/nanoscale devices, surface functionalization is essential to achieve function and performance superior to those that originate from the inherent bulk material properties. As a method of surface functionalization, we dip-coated nanometer-thick liquid lubricant films onto solid surfaces and then patterned the lubricant films with ultraviolet (UV) irradiation through a photomask. Surface topography, adhesion, and friction measurements demonstrated that the patterned films feature a concave–convex thickness distribution with thicker lubricant in the irradiated regions and a functional distribution with lower adhesion and friction in the irradiated convex regions. The pattern linewidth ranged from 100 to as fine as 0.5 μm. The surface functionalization effect of UV-patterning was investigated by measuring the water contact angles, surface energies, friction forces, and depletion of the patterned, as-dipped, and full UV-irradiated lubricant films. The full UV-irradiated lubricant film was hydrophobic with a water contact angle of 102.1°, and had lower surface energy, friction, and depletion than the as-dipped film, which was hydrophilic with a water contact angle of 80.7°. This demonstrates that UV irradiation substantially improves the surface and tribological properties of the nanometer-thick liquid lubricant films. The UV-patterned lubricant films exhibited superior surface and tribological properties than the as-dipped film. The water contact angle increased and the surface energy, friction, and depletion decreased as the pattern linewidth decreased. In particular, the 0.5-μm patterned lubricant

  8. Friction and lubrication modeling in sheet metal forming simulations of a Volvo XC90 inner door

    Sigvant, M.; Pilthammar, J.; Hol, J.; Wiebenga, J. H.; Chezan, T.; Carleer, B.; van den Boogaard, A. H.


    The quality of sheet metal formed parts is strongly dependent on the tribology, friction and lubrication conditions that are acting in the actual production process. Although friction is of key importance, it is currently not considered in detail in stamping simulations. This paper presents a selection of results considering friction and lubrication modeling in sheet metal forming simulations of the Volvo XC90 right rear door inner. For this purpose, the TriboForm software is used in combination with the AutoForm software. Validation of the simulation results is performed using door inner parts taken from the press line in a full-scale production run. The results demonstrate the improved prediction accuracy of stamping simulations by accounting for accurate friction and lubrication conditions, and the strong influence of friction conditions on both the part quality and the overall production stability.

  9. Poiseuille flow past a nanoscale cylinder in a slit channel: Lubrication theory versus molecular dynamics analysis

    Rahmani, Amir M; Jupiterwala, Mehlam; Colosqui, Carlos E


    Plane Poiseuille flow past a nanoscale cylinder that is arbitrarily confined (i.e., symmetrically or asymmetrically confined) in a slit channel is studied via hydrodynamic lubrication theory and molecular dynamics simulations, considering cases where the cylinder remains static or undergoes thermal motion. Lubrication theory predictions for the drag force and volumetric flow rate are in close agreement with molecular dynamics simulations of flows having molecularly thin lubrication gaps, despite the presence of significant structural forces induced by the crystalline structure of the modeled solid. While the maximum drag force is observed in symmetric confinement, i.e., when the cylinder is equidistant from both channel walls, the drag decays significantly as the cylinder moves away from the channel centerline and approaches a wall. Hence, significant reductions in the mean drag force on the cylinder and hydraulic resistance of the channel can be observed when thermal motion induces random off-center displace...

  10. Study of lubrication behavior of pure water for hydrophobic friction pair


    The perfluorooctyltrichlorosilane molecular layer was self-assembled on glass plate. The tribological properties of the molecular layer in water were studied with the method of ball on disk. An interesting phenomenon was found that low friction coefficients of 0.02―0.08 were obtained when the friction pair was lubricated with only a water droplet. Whereas, when the friction pair was encircled with large amount of water or fully immersed in water, the friction coefficient was higher than that under a droplet lubrication. A mechanism of water droplet lubrication was proposed that the surface tension caused by the solid-liquid-air three-phase interface makes water molecules enter into the contact zone, which separates the two friction surfaces and provides a low friction coefficient. However, water film can hardly form when more water encircles the friction pair, due to the attraction between water molecules.

  11. Identification of tribological research and development needs for lubrication of advanced heat engines

    Fehrenbacher, L.L.; Levinson, T.M.


    The continuous evolution of higher power density propulsion systems has always fueled the search for materials and lubricants with improved thermal and/or durability characteristics. Tribology of the upper cylinder region is the major technology roadblock in the path of the adiabatic diesel engine which has an energy reduction potential that exceeds that of all other engine development types. This tribology assessment resulted in the following major conclusions: a low friction and a low wear seal between the ring belt and cylinder bore are the most critical tribology functions in the diesel combustion chamber; development of solid lubrication systems will not satisfy the simultaneous low friction and low wear requirements in the upper cylinder area; development of separate upper cylinder liquid lubrication systems offers the most attractive design alternative for meeting the operational goals of future ''minimum cooled'' diesel engines.

  12. Experiments on Ultrasonic Lubrication Using a Piezoelectrically-assisted Tribometer and Optical Profilometer.

    Dong, Sheng; Dapino, Marcelo


    Friction and wear are detrimental to engineered systems. Ultrasonic lubrication is achieved when the interface between two sliding surfaces is vibrated at a frequency above the acoustic range (20 kHz). As a solid-state technology, ultrasonic lubrication can be used where conventional lubricants are unfeasible or undesirable. Further, ultrasonic lubrication allows for electrical modulation of the effective friction coefficient between two sliding surfaces. This property enables adaptive systems that modify their frictional state and associated dynamic response as the operating conditions change. Surface wear can also be reduced through ultrasonic lubrication. We developed a protocol to investigate the dependence of friction force reduction and wear reduction on the linear sliding velocity between ultrasonically lubricated surfaces. A pin-on-disc tribometer was built which differs from commercial units in that a piezoelectric stack is used to vibrate the pin at 22 kHz normal to the rotating disc surface. Friction and wear metrics including effective friction force, volume loss, and surface roughness are measured without and with ultrasonic vibrations at a constant pressure of 1 to 4 MPa and three different sliding velocities: 20.3, 40.6, and 87 mm/sec. An optical profilometer is utilized to characterize the wear surfaces. The effective friction force is reduced by 62% at 20.3 mm/sec. Consistently with existing theories for ultrasonic lubrication, the percent reduction in friction force diminishes with increasing speed, down to 29% friction force reduction at 87 mm/sec. Wear reduction remains essentially constant (49%) at the three speeds considered.

  13. Antioxidative activity of red wine with the in-creased share of phenolic compounds from solid parts of grape



    Full Text Available The structure and amount of phenolic compounds in the wine depend on the grapevine variety, agroecologic conditions and a way of vinification. The influence of pomace enrichment with solid parts of grape (stem and grape seeds during maceration on the antioxidative activity of red wines was investigated. The antioxidative activity of red wines towards DPPH• and hydroxyl (•OH radicals was determined by the electron spin resonance (ESR spectroscopy. The addition of stem to the pomace had no significant influence on the antioxidative wine activity increase, whereas enriching of pomace with 120 g seeds/kg of pomace resulted in the increase of antioxidative capacity of a wine. In the wine enriched with tannins and flavan-3-ols from the seeds, the antioxidative activity towards DPPH• (AADPPH• was 100%. None of the applied clarifiers showed a significant influence on the antioxidative activity of these wine samples. The antioxidative activity, measured as DPPH• scavenging activity, of the wine supplemented by seeds remained unchanged, showing 100% efficiency after the treatment by all tested fining agents. A significant difference in antioxidative activities towards hydroxyl radicals (AA•OH between the two wines was found. The antioxidative activity of the wine Merlot was higher than the antioxidative activity of the wine Cabernet sauvignon.

  14. A distributed real-time model of degradation in a solid oxide fuel cell, part I: Model characterization

    Zaccaria, V.; Tucker, D.; Traverso, A.


    Despite the high efficiency and flexibility of fuel cells, which make them an attractive technology for the future energy generation, their economic competitiveness is still penalized by their short lifetime, due to multiple degradation phenomena. As a matter of fact, electrochemical performance of solid oxide fuel cells (SOFCs) is reduced because of different degradation mechanisms, which depend on operating conditions, fuel and air contaminants, impurities in materials, and others. In this work, a real-time, one dimensional (1D) model of a SOFC is used to simulate the effects of voltage degradation in the cell. Different mechanisms are summarized in a simple empirical expression that relates degradation rate to cell operating parameters (current density, fuel utilization and temperature), on a localized basis. Profile distributions of different variables during cell degradation are analyzed. In particular, the effect of degradation on current density, temperature, and total resistance of the cell are investigated. An analysis of localized degradation effects shows how different parts of the cell degrade at a different time rate, and how the various profiles are redistributed along the cell as consequence of different degradation rates.

  15. A study of mechanisms of liquid lubrication in metal forming

    Bech, Jakob Ilsted; Bay, Niels; Eriksen, Morten


    Applying a transparent tool technique the lubrication in plane strip drawing of aluminium sheet is studied providing the strip with surface pockets for entrapment of lubricant. The compression and eventual escape of trapped lubricant by Micro Plasto HydroDynamic Lubrication (MPHDL) as well as Micro...

  16. Application of a Biodegradable Lubricant in a Diesel Vehicle

    Schramm, Jesper


    , NOx, THC, PM, lubricant-SOF and PAH from one diesel and one gasoline type vehicle using biodegradable lubricants and conventional lubricants. This paper describes the results of the experiments with the diesel type vehicle only. Lubricant consumption and fuel consumption are other important parameters...

  17. A study of mechanisms of liquid lubrication in metal forming

    Bech, Jakob Ilsted; Bay, Niels; Eriksen, Morten


    Applying a transparent tool technique the lubrication in plane strip drawing of aluminium sheet is studied providing the strip with surface pockets for entrapment of lubricant. The compression and eventual escape of trapped lubricant by Micro Plasto HydroDynamic Lubrication (MPHDL) as well as Mic...

  18. 7 CFR 2902.43 - Chain and cable lubricants.


    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Chain and cable lubricants. 2902.43 Section 2902.43... Items § 2902.43 Chain and cable lubricants. (a) Definition. Products designed to provide lubrication in... and cable lubricants. By that date, Federal agencies that have the responsibility for drafting...

  19. One of possible variants of the organization for recycling lubricate cooling of technological means for small businesses

    Rusica, I.; Toca, A.; Stingaci, I.; Scaticailov, S.; Scaticailov, I.; Marinescu, O.; Kosenko, P.


    In the paper we analyze the application lubricate cooling technological environment in the processing of various materials in the past century greatly have increased cutting speed and respectively, has increased productivity [1]. Today, none of production in which anyway is used metal cutting machines of all types (milling, turning, grinding, drilling, etc.) is not without lubricant cooling technological liquid which in turn are designed to reduce cutting force and the load on metal cutting machine tools and machined parts in order to increase durability machine tools and reduce errors of processing details and also in resource energy saving. When using lubricate cooling technological environment reduces the temperature in the cutting zone resulting in higher tool life and the preservation of the surface structure being treated reducing wear of metal parts of the machine. Typically, lubricant cooling process fluids is used without replacing as long as possible not yet beginning to negatively affect the quality of process. However life expectancy lubricate cooling technological environment is limited. According to existing normative acts every kind of lubricate cooling technological environment through certain time must be deleted by from the system and subjected to a recycling. Lubricate cooling technological environment must be disposed of for the following reasons: occurs the microbial and the mechanical pollution cutting fluid, free oil impairs operational characteristics cutting fluid and increases consumption.

  20. On the determination of missing boundary data for solids with nonlinear material behaviors, using displacement fields measured on a part of their boundaries

    Andrieux, Stéphane; Baranger, Thouraya N.


    The paper is devoted to the derivation of a numerical method for expanding available mechanical fields (stress vector and displacements) on a part of the boundary of a solid into its interior and up to unreachable parts of its boundary (with possibly internal surfaces). This expansion enables various identification or inverse problems to be solved in mechanics. The method is based on the solution of a nonlinear elliptic Cauchy problem because the mechanical behavior of the solid is considered as nonlinear (hyperelastic or elastoplastic medium). Advantage is taken of the assumption of convexity of the potentials used for modeling the constitutive equation, encompassing previous work by the authors for linear elastic solids, in order to derive an appropriate error functional. Two illustrations are given in order to evaluate the overall efficiency of the proposed method within the framework of small strains and isothermal transformation.

  1. Energy Dissipation and Apparent Viscosity of Semi-solid Metal during Rheological Processes Part Ⅰ: Energy Dissipation

    Wen LIU; Shuming XING; Peiwei BAO; Milan ZHANG; Liming XIAO


    The energy dissipation caused by the viscous force has great effects on the flow property of semi-solid metal during rheological processes such as slurry preparing, delivering and cavity filling. Experimental results in this paper indicate that the viscous friction between semi-solid metal and pipe wall, the collisions among the solid particles, and the liquid flow around particles are the three main types of energy dissipation. On the basis of the hydromechanics, the energy dissipation calculation model is built. It is demonstrated that the micro-structural parameters such as effective solid fraction, particle size and shape, and flow parameters such as the mean velocity, the fluctuant velocity of particles and the relative velocity between the fluid and solid phase, affect the energy dissipation of semi-solid metal.

  2. Tribological Characterization of NiAl Self-Lubricating Composites Containing V2O5 Nanowires

    Huang, Yuchun; Ibrahim, Ahmed Mohamed Mahmoud; Shi, Xiaoliang; Radwan, Amr Rady; Zhai, Wenzheng; Yang, Kang; Xue, Bing


    In order to improve the tribological properties of NiAl self-lubricating composites, V2O5 nanowires with average width of 39 nm were synthesized by hydrothermal method. Furthermore, NiAl self-lubricating composites containing V2O5 nanowires (NAV) were successfully fabricated using spark plasma sintering technique. The tribological characteristics and wear mechanisms of NAV were evaluated at different sliding speeds, counterface ball materials and elevated temperatures. The results revealed that the frictional properties of NAV improved slightly with adding V2O5 nanowires at room temperature if compared to NiAl self-lubricating composites without solid lubricant as investigated in previous studies, while the wear mechanisms of NAV change widely with the change of the counterface ball materials and sliding velocities. V2O5 nanowires showed a beneficial effect on tribological performance of NAV at high temperatures owing to the formation of the V2O5-enriched glaze film at temperatures above 700 °C, which acts as the lubricous and protective mask against the severe wear.

  3. The effect of late-phase contrast enhancement on semi-automatic software measurements of CT attenuation and volume of part-solid nodules in lung adenocarcinomas

    Cohen, J.G.; Goo, J.M.; Yoo, R.E.; Park, S.B.; Ginneken, B. van; Ferretti, G.R.; Lee, C.H.; Park, C.M.


    OBJECTIVES: To evaluate the differences in semi-automatic measurements of CT attenuation and volume of part-solid nodules (PSNs) between unenhanced and enhanced CT scans. MATERIALS AND METHODS: CT scans including unenhanced and enhanced phases (slice thickness 0.625 and 1.25mm, respectively) for 53

  4. The behaviour of lubricated EHD contacts subjected to vibrations

    Zhang, X.; Glovnea, R. P.


    Machine components containing contacts working in elastohydrodynamic (EHD) conditions are often subjected to vibrations. These may be originated from the mechanism or machine the contact is part of, the surrounding environment and within the contact itself. The influence of vibrations upon the behaviour of elastohydrodynamic films has been studied experimentally in a number of papers, but a comprehensive study of the effect of the parameters of the oscillatory motion upon the film thickness has not been carried out yet. In this study the authors evaluate the effect of the frequency of the oscillatory motion upon the EHD film thickness. Optical interferometry is used to measure lubricant film thickness in a ball-on-flat disc arrangement. A high – speed camera records the interferometric images for later analysis and conversion into film thickness maps. The disc runs at a constant angular velocity while the ball is driven by the traction forces developed in the EHD film. In steady state conditions, this would ensure pure rolling conditions, however in the present investigation the ball is subjected to harmonic vibrations in a direction perpendicular to the plane of the film. The contact under study is lubricated by basic oils and the temperature is kept at a constant value of 60°C. The aim of this paper is to understand how vibrations influence the lubricant film formation.

  5. ¹³C solid-state NMR analysis of the most common pharmaceutical excipients used in solid drug formulations, Part I: Chemical shifts assignment.

    Pisklak, Dariusz Maciej; Zielińska-Pisklak, Monika Agnieszka; Szeleszczuk, Łukasz; Wawer, Iwona


    Solid-state NMR is an excellent and useful method for analyzing solid-state forms of drugs. In the (13)C CP/MAS NMR spectra of the solid dosage forms many of the signals originate from the excipients and should be distinguished from those of active pharmaceutical ingredient (API). In this work the most common pharmaceutical excipients used in the solid drug formulations: anhydrous α-lactose, α-lactose monohydrate, mannitol, sucrose, sorbitol, sodium starch glycolate type A and B, starch of different origin, microcrystalline cellulose, hypromellose, ethylcellulose, methylcellulose, hydroxyethylcellulose, sodium alginate, magnesium stearate, sodium laurilsulfate and Kollidon(®) were analyzed. Their (13)C CP/MAS NMR spectra were recorded and the signals were assigned, employing the results (R(2): 0.948-0.998) of GIPAW calculations and theoretical chemical shifts. The (13)C ssNMR spectra for some of the studied excipients have not been published before while for the other signals in the spectra they were not properly assigned or the assignments were not correct. The results summarize and complement the data on the (13)C ssNMR analysis of the most common pharmaceutical excipients and are essential for further NMR studies of API-excipient interactions in the pharmaceutical formulations.

  6. Lubrication in strip cold rolling process

    Jianlin Sun; Yonglin Kang; Tianguo Xiao; Jianze Wang


    A lubrication model was developed for explaining how to form an oil film in the deformation zone, predicting the film thickness and determining the characteristics of lubrication in the strip rolling process, combined with the knowledge of hydrodythicknesses in the strip cold rolling. Results from the experiment and calculation show that the oil film forming in hydrodynamic lubrication is up to the bit angle and a higher rolling speed or a higher rolling oil viscosity. The mechanism of mechanical entrainment always affects the film thickness that increases with the rolling oil viscosity increasing or the reduction rate decreasing in rolling.

  7. Lubricants and drilling fluids from plant origin

    Belorgeot, C.; Renault, P. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France)


    For drilling fluids and lubricants (hydraulic fluids, un-molding oils, metal working oils and two-stroke engines oils), mineral oils present environmental risks and have to be replaced by more biodegradable products, such as vegetable bio-lubricants. First generation of bio-lubricants (colza oils, soybean oils, sun flower oils) with additives (anti- oxidants), second generation coming from the transformation of vegetable oils (polyol or fatty acids esters, dimers of fatty acids esterified with oxo alcohol, and esters of special alcohols), third generation coming from a deep transformation of vegetable oils are shortly listed with industrial applications. (A.B.). 5 tabs.

  8. PetroChina Continues to Restructure Lubricants Assets

    Zhang Bingxing


    @@ PetroChina has recently separated the lubricants assets of the two oil refining enterprises at Liaohe Oil Field and Yumen Oil Field and transferred them to PetroChina Lubricating Oil Company. As a result,the lubricating oil company has currently nine regional lubricants production plants nationwide with six regional sales centers and two research centers,forming a large-scale lubricants complex with integration of production, marketing and technical development.

  9. Effects of lubricant's friction coefficient on warm compaction powder metallurgy

    LI Yuan-yuan; NGAI Tungwai Leo; WANG Shng-lin; ZHU Min; CHEN Wei-ping


    The correct use of lubricant is the key of warm compaction powder metallurgy.Different lubricants produce different lubrication effects and their optimal application temperature will be different.Three different lubricants were used to study the effects of friction coefficient on warm compaction process.Friction coefficients of these lubricants were measured at temperatures ranging from ambient temperature to 200 ℃.Iron-base samples were prepared using different processing temperatures and their green compact densities were studied.

  10. Elastohydrodynamic Lubrication with Polyolester Lubricants and HFC Refrigerants, Final Report, Volume 2

    Gunsel, Selda; Pozebanchuk, Michael


    Lubrication properties of refrigeration lubricants were investigated in high pressure nonconforming contacts under different conditions of temperature, rolling speed, and refrigerant concentration. The program was based upon the recognition that the lubrication regime in refrigeration compressors is generally elastohydrodynamic or hydrodynamic, as determined by the operating conditions of the compressor and the properties of the lubricant. Depending on the compressor design, elastohydrodynamic lubrication conditions exist in many rolling and sliding elements of refrigeration compressors such as roller element bearings, gears, and rotors. The formation of an elastohydrodynamic film separating rubbing surfaces is important in preventing the wear and failure of compressor elements. It is, therefore, important to predict the elastohydrodynamic (EHD) performance of lubricants under realistic tribocontact renditions. This is, however, difficult as the lubricant properties that control film formation are critically dependent upon pressure and shear, and cannot be evaluated using conventional laboratory instruments. In this study, the elastohydrodynamic behavior of refrigeration lubricants with and without the presence of refrigerants was investigated using the ultrathin film EHD interferometry technique. This technique enables very thin films, down to less than 5 nm, to be measured accurately within an EHD contact under realistic conditions of temperature, shear, and pressure. The technique was adapted to the study of lubricant refrigerant mixtures. Film thickness measurements were obtained on refrigeration lubricants as a function of speed, temperature, and refrigerant concentration. The effects of lubricant viscosity, temperature, rolling speed, and refrigerant concentration on EHD film formation were investigated. From the film thickness measurements, effective pressure-viscosity coefficients were calculated. The lubricants studied in this project included two

  11. Vegetable oil basestocks for lubricants

    Garcés, Rafael


    Full Text Available The use of vegetable biodegradable basestocks for lubricant oils present several advantages over the much more extended mineral bases. These advantages refer to biodegradability, a renewable feedstock of local production, lubricant and viscosity index and lower costs than synthetic lubricant bases. Despite these benefits, their use in industry and motor vehicles is not yet extensive due their lower stability and higher pour points. Vegetable oils are esters of fatty acids and glycerol, and their physicochemical properties rely mainly on the composition of their acyl moieties. Thus, to assure the maximum levels of stability while maintaining acceptable behavior at low temperatures, monounsaturated fatty acids are preferred for this purpose. The presence of natural antioxidants also improves the properties of these vegetable based stocks as lubricants. These oils usually require additives to improve their viscosity value, oxidative stability and properties at low temperatures. In the present work, the different sources of vegetable oils appropriate for biolubricant production were reviewed. Their properties and the future improvement of the oil bases, oil based stock production, uses and additives are discussed.

    El uso de bases vegetales biodegradables para aceites lubricantes presenta varias ventajas sobre las mucho más extendidas bases minerales. Estas ventajas se centran sobre todo en su biodegradabilidad, en ser un recurso renovable de producción local, en su lubricidad y en su índice de viscosidad, presentando además costes más bajos que las bases sintéticas. Sin embargo, estas ventajas no han extendido el uso de bases vegetales ni en industria ni en automoción debido a su menor estabilidad y sus mayores puntos críticos de fluidez. Los aceites vegetales son ésteres de ácidos grasos y glicerol y sus propiedades físico-químicas dependen principalmente de su composición acílica. Así, para asegurar los máximos niveles de

  12. Temporal and spatial variations in total suspended and dissolved solids in the upper part of Manoa stream, Hawaii

    Augustijn, Dionysius C.M.; Fares, Ali; Tran, Dai Ngia


    Hawaiian watersheds are small, steep, and receive high intensity rainfall events of non-uniform distribution. These geographic and weather patterns result in flashy streams of strongly variable water quality even within various stream segments. Total suspended solids (TSS) and total dissolved solids

  13. Application of Terahertz Attenuated Total Reflection Spectroscopy to Detect Changes in the Physical Properties of Lactose during the Lubrication Process Required for Drug Formulation.

    Dohi, Masafumi; Momose, Wataru; Yamashita, Kazunari; Hakomori, Tadashi; Sato, Shusaku; Noguchi, Shuji; Terada, Katsuhide


    Manufacturing the solid dosage form of an orally administered drug requires lubrication to enhance manufacturability, ensuring that critical quality attributes such as disintegration and dissolution of the drug product are maintained during manufacture. Here, to evaluate lubrication performance during manufacture, we used terahertz attenuated total reflection (THz-ATR) spectroscopy to detect differences in the physical characteristics of the lubricated powder. We applied a simple formulation prepared by blending granulated lactose as filler with magnesium stearate as lubricant. A flat tablet was prepared using the lubricated powder to acquire sharp THz-ATR absorption peaks of the samples. First, we investigated the effects of lubricant concentration and compression pressure on preparation of the tablet and then determined the effect of the pressure applied to samples in contact with the ATR prism on sample absorption amplitude. We focused on the differences in the magnitudes of spectra at the lactose-specific frequency. Second, we conducted the dynamic lubrication process using a 120-L mixer to investigate differences in the magnitudes of absorption corresponding to the lactose-specific frequency during lubrication. In both studies, enriching the lubricated powder with a higher concentration of magnesium stearate or prolonging blending time correlated with higher magnitudes of spectra at the lactose-specific frequency. Further, in the dynamic lubrication study, the wettability and disintegration time of the tablets were compared with the absorption spectra amplitudes at the lactose-specific frequency. We conclude that THz-ATR spectroscopy is useful for detecting differences in densities caused by a change in the physical properties of lactose during lubrication.

  14. Differentiating pre- and minimally invasive from invasive adenocarcinoma using CT-features in persistent pulmonary part-solid nodules in Caucasian patients

    Cohen, Julien G., E-mail: [Clinique Universitaire de Radiologie et Imagerie Médicale (CURIM), Université Joseph Fourier, Centre Hospitalier Universitaire de Grenoble, CS 10217, 38043 Grenoble Cedex 9 (France); Reymond, Emilie [Clinique Universitaire de Radiologie et Imagerie Médicale (CURIM), Université Joseph Fourier, Centre Hospitalier Universitaire de Grenoble, CS 10217, 38043 Grenoble Cedex 9 (France); Lederlin, Mathieu [Service de Radiologie, Université Segalen Bordeaux, Centre Hospitalier Universitaire de Bordeaux, 12 rue Dubernat, 33404 Bordeaux Cedex (France); Medici, Maud [Centre d’Investigation Clinique – Innovation Technologique (CIC-IT), Pavillon Taillefer, 38706 La Tronche Cedex (France); Lantuejoul, Sylvie [Departement d’Anatomie et Cytologie Pathologique (DACP), Université Joseph Fourier, Centre Hospitalier Universitaire de Grenoble, CS 10217, 38043 Grenoble Cedex 9 (France); Laurent, François [Service de Radiologie, Université Segalen Bordeaux, Centre Hospitalier Universitaire de Bordeaux, 12 rue Dubernat, 33404 Bordeaux Cedex (France); Arbib, François [Departement de Pneumologie, Université Joseph Fourier, Centre Hospitalier Universitaire de Grenoble, CS 10217, 38043 Grenoble Cedex 9 (France); Jankowski, Adrien [Clinique Universitaire de Radiologie et Imagerie Médicale (CURIM), Université Joseph Fourier, Centre Hospitalier Universitaire de Grenoble, CS 10217, 38043 Grenoble Cedex 9 (France); and others


    Highlights: •We analyzed CT-features of part-solid ground glass nodules in Caucasians. •These CT-features were compared to pathology on full resection specimen. •Several CT-features can help differentiating invasive adenocarcinoma. •A solid component larger than 5 mm had 100% sensitivity for invasive adenocarcinoma. -- Abstract: Objective: To retrospectively investigate the diagnostic value of pre-operative CT-features between pre/minimally invasive and invasive lesions in part-solid persistent pulmonary ground glass nodules in a Caucasian population. Materials and methods: Retrospective review of two pre-operative CTs for 31 nodules in 30 patients. There were 10 adenocarcinomas in situ, 1 minimally invasive adenocarcinoma, 20 invasive adenocarcinomas. We analyzed the correlation between histopathology and the following CT-features: maximal axial diameter, maximal orthogonal axial diameter, height, density, size of solid component, air bronchogram, pleural retraction, nodule mass, disappearance rate and their evolution during follow-up. Results: In univariate analysis, invasive adenocarcinomas had a higher maximal height, density, solid component size, mass, a lower disappearance rate and presented more often with pleural retraction (p < 0.05). After logistic regression performed with the uncorrelated parameters using a method of selection of variables, only the size of solid component remained significant, with 100% sensitivity for invasive adenocarcinoma when larger than 5 mm. Conclusion: Preoperative CT-features can help differentiating in situ and minimally invasive adenocarcinomas from invasive adenocarcinomas in Caucasian patients. A solid component larger than 5 mm in diameter had 100% sensitivity for the diagnosis of invasive adenocarcinoma.

  15. Nano-solids in manganese nodules from northern part of Pacific Ocean floor——Nano-solids in minerals and prospects of its uses in industry

    施倪承; 马喆生; 何万中; 罗济民


    The study of the crystal structure and particle size of manganese nodules from the northernpart of the Central Pacific Ocean floor indicates that besides the phases of todorokite,birnessite and δ-MnOwith the crystallite size at the micron scale,there are many other multi-phase solids having particle size at thenanomater scale.The chemical analysis,TEM study,M(?)ssbauer spectroscopy and differential thermal analysisshow that they are mainly ferri-hydroxides with the short-range ordered structure similar to that of goethiteand lepidocrocite.The small-angle X-ray scattering measurements indicate that the peak position of the particlesize distribution is at 5-10nm,hence the existence of nano-solids in minerals is confirmed.

  16. Parametrical design of parts based on solid works by VB%用VB实现Solid Works对零件的参数化设计

    王文彬; 吴文英


    介绍了零件三维建模的参数化设计,通过可视化程序设计语言Visual Basic来调用三维建模软件Solid Works绘制出所需的零件,这样使得图形绘制简单,编辑方便,大大提高了工作效率.

  17. A Multipurpose Additive for Lubricating Oils,

    The report describes the synthesis and properties of S-(3,5-di-tert-butyl-4-hydroxybenzyl)-O-O-(alkyl or aryl) phosphorodithioate. This compound was synthesized as wear inhibitor and antioxidant for lubricating oils .

  18. Potential of vegetable oils for lubricants

    Vegetable oils offer significant advantages in terms of resource renewability, biodegradability, and comparable performance properties to petroleum-based products. The petroleum-based lubricants render unfavorable impact on the environment. With the growing environmental concerns, seed oils are find...

  19. Liquid lubricants for advanced aircraft engines

    Loomis, William R.; Fusaro, Robert L.


    An overview of liquid lubricants for use in current and projected high performance turbojet engines is discussed. Chemical and physical properties are reviewed with special emphasis placed on the oxidation and thermal stability requirements imposed upon the lubrication system. A brief history is given of the development of turbine engine lubricants which led to the present day synthetic oils with their inherent modification advantages. The status and state of development of some eleven candidate classes of fluids for use in advanced turbine engines are discussed. Published examples of fundamental studies to obtain a better understanding of the chemistry involved in fluid degradation are reviewed. Alternatives to high temperature fluid development are described. The importance of continuing work on improving current high temperature lubricant candidates and encouraging development of new and improved fluid base stocks are discussed.

  20. Fuels and Petroleum, Oil & Lubricants (POL) Laboratories

    Federal Laboratory Consortium — The Fuels and Lubricants Technology Team operates and maintains the Fuels and POL Labs at TARDEC. Lab experts adhere to standardized American Society for Testing and...

  1. A Biomimetic Approach to Lubricate Engineering Materials

    Røn, Troels

    the neutral PEG and charged PAA buoyant blocks, the neutral showed superior adsorption onto hydrophobic poly(dimethylsiloxane) (PDMS) surfaces from neutral aqueous conditions. Neutral PEG based copolymers showed substantial adsorption for both PS and PMEA as the anchoring block, whereas charged PAA......-based copolymersshowed effective adsorption only for PMEA anchoring block. PAA-b-PS diblock copolymer’s poor lubricity for the PDMS-PDMS sliding contact was well correlated with poor adsorption. PAA-b-PMEA copolymers, despite their significant degree of adsorption, showed little lubricity. When adding NaClto the aqueous...... solution or by lowering the pH, both the adsorption and lubricity of the PAA-b-PMEA diblock copolymer solutions improved. The poor adsorption and inferior aqueous lubricating properties of the polyelectrolyte based (PAA) diblock copolymers compared to their PEG-based counterparts was mainly attributed...

  2. ¹³C solid-state NMR analysis of the most common pharmaceutical excipients used in solid drug formulations Part II: CP kinetics and relaxation analysis.

    Pisklak, Dariusz Maciej; Zielińska-Pisklak, Monika; Szeleszczuk, Łukasz; Wawer, Iwona


    Excipients used in the solid drug formulations differ in their NMR relaxation and (13)C cross-polarization (CP) kinetics parameters. Therefore, experimental parameters like contact time of cross-polarization and repetition time have a major impact on the registered solid state NMR spectra and in consequence on the results of the NMR analysis. In this work the CP kinetics and relaxation of the most common pharmaceutical excipients: anhydrous α-lactose, α-lactose monohydrate, mannitol, sucrose, sorbitol, sodium starch glycolate type A and B, starch of different origin, microcrystalline cellulose, hypromellose, ethylcellulose, methylcellulose, hydroxyethylcellulose, sodium alginate, magnesium stearate, sodium laurilsulfate and Kollidon(®) were analyzed. The studied excipients differ significantly in their optimum repetition time (from 5 s to 1200 s) and T(1ρ)(I) parameters (from 2 ms to 73 ms). The practical use of those differences in the excipients composition analysis was demonstrated on the example of commercially available tablets containing indapamide as an API. The information presented in this article will help to choose the correct acquisition parameters and also will save the time and effort needed for their optimization in the NMR analysis of the solid drug formulations.

  3. Engine Auxiliary System Guideline: Lubricating Oil Systems

    Linna, Joni


    This thesis was done for Wärtsilä Technical Services organization, the purpose of this work was to gather and structure information about the lubricating oil systems from the company’s internal databases, interviews with system specialists and from different literature sources covering Ship Power and Power Plant products. The outcome was a guideline, covering typical power plant and marine system descriptions, all components used in the lubricating oil system with their functional description...

  4. Advanced lubrication systems and materials. Final report

    Hsu, S.


    This report described the work conducted at the National Institute of Standards and Technology under an interagency agreement signed in September 1992 between DOE and NIST for 5 years. The interagency agreement envisions continual funding from DOE to support the development of fuel efficient, low emission engine technologies in terms of lubrication, friction, and wear control encountered in the development of advanced transportation technologies. However, in 1994, the DOE office of transportation technologies was reorganized and the tribology program was dissolved. The work at NIST therefore continued at a low level without further funding from DOE. The work continued to support transportation technologies in the development of fuel efficient, low emission engine development. Under this program, significant progress has been made in advancing the state of the art of lubrication technology for advanced engine research and development. Some of the highlights are: (1) developed an advanced high temperature liquid lubricant capable of sustaining high temperatures in a prototype heat engine; (2) developed a novel liquid lubricant which potentially could lower the emission of heavy duty diesel engines; (3) developed lubricant chemistries for ceramics used in the heat engines; (4) developed application maps for ceramic lubricant chemistry combinations for design purpose; and (5) developed novel test methods to screen lubricant chemistries for automotive air-conditioning compressors lubricated by R-134a (Freon substitute). Most of these findings have been reported to the DOE program office through Argonne National Laboratory who manages the overall program. A list of those reports and a copy of the report submitted to the Argonne National Laboratory is attached in Appendix A. Additional reports have also been submitted separately to DOE program managers. These are attached in Appendix B.

  5. New Lubricants Protect Machines and the Environment


    In 1994, NASA and Lockheed Martin Space Operations commissioned Sun Coast Chemicals of Daytona Inc to develop a new type of lubricant that would be safe for the environment and help "grease the wheels" of the shuttle-bearing launcher platform. Founded in 1989, Sun Coast Chemicals is known amongst the racing circuit for effective lubricants that help overcome engine and transmission problems related to heat and wear damage. In a matter of weeks, Sun Coast Chemical produced the biodegradable, high-performance X-1R Crawler Track Lube. In 1996, Sun Coast Chemical determined there was a market for this new development, and introduced three derivative products, Train Track Lubricant, Penetrating Spray Lubricant, and Biodegradable Hydraulic Fluid, and then quickly followed with a gun lubricant/cleaner and a fishing rod and reel lubricant. Just recently, Sun Coast introduced the X-1R Corporation, which folds the high-performance, environmentally safe benefits into a full line of standard automotive and specially formulated racing products. The entire X-1R automotive product line has stood up to rigorous testing by groups such as the American Society of Mechanical Engineers, the Swedish National Testing and Research Institute, the Department of Mechanical Engineering at Oakland University (Rochester, Michigan), and Morgan-McClure Motorsports (Abingdon, Virginia). The X-1R Corporation also markets "handy packs" for simple jobs around the house, consisting of a multi-purpose, multi-use lubricant and grease. In 2003, The X-1R Corporation teamed up with Philadelphia-based Penn Tackle Manufacturing Co., a leading manufacturer of fishing tackle since 1932, to jointly develop and market a line of advanced lubrication products for saltwater and freshwater anglers

  6. Biotribology :articular cartilage friction, wear, and lubrication

    Schroeder, Matthew O


    This study developed, explored, and refined techniques for the in vitro study of cartilage-on-cartilage friction, deformation, and wear. Preliminary results of in vitro cartilage-on- cartilage experiments with emphasis on wear and biochemistry are presented. Cartilage-bone specimens were obtained from the stifle joints of steers from a separate controlled study. The load, sliding speed, and traverse of the lower specimens were held constant as lubricant and test length were varied. Lubric...

  7. Tribology experiment. [journal bearings and liquid lubricants

    Wall, W. A.


    A two-dimensional concept for Spacelab rack 7 was developed to study the interaction of liquid lubricants and surfaces under static and dynamic conditions in a low-gravity environment fluid wetting and spreading experiments of a journal bearing experiments, and means to accurately measure and record the low-gravity environment during experimentation are planned. The wetting and spreading process of selected commercial lubricants on representative surface are to the observes in a near-zero gravity environment.

  8. Materials as additives for advanced lubrication

    Pol, Vilas G.; Thackeray, Michael M.; Mistry, Kuldeep; Erdemir, Ali


    This invention relates to carbon-based materials as anti-friction and anti-wear additives for advanced lubrication purposes. The materials comprise carbon nanotubes suspended in a liquid hydrocarbon carrier. Optionally, the compositions further comprise a surfactant (e.g., to aid in dispersion of the carbon particles). Specifically, the novel lubricants have the ability to significantly lower friction and wear, which translates into improved fuel economies and longer durability of mechanical devices and engines.

  9. Compensation of Cross-Coupling Stiffness and Increase of Direct Damping in Multirecess Journal Bearings using Active Hybrid Lubrication

    Santos, Ilmar; Watanabe, F.Y.


    journal bearings (HJB). When part of hydrostatic pressure is also dynamically modified by means of hydraulic control systems, one refers to the active lubrication. The main contribution of the present theoretical work is to show that it is possible to reduce cross-coupling stiffness and increase...... the direct damping coefficients by means of the active lubrication, what leads to rotor-bearing systems with larger threshold of stability....



    @@High VI lubricating oil is produced in hydrocracker through hydrocracking (HDC) and hydroisome-rization reactions. In order to effectively produce high VI component, such as iso-pafaffins and monocyclic naphtenes, it is important to load suitable HDC catalysts and operate them in the appropriate reaction conditions.   Nippon Mitsubishi Oil Corporation (NMOC) and its affiliate company, Nippon Mitsubishi Petroleum Refining Company (NMPRC) reported their original HDC catalysts four years ago in this Japan-China joint se-minar in Beijing[1]. NMOC and NMPRC operate their hydrocracker both in fuel oil production mode and in lubricating oil production mode. In lubricating oil production mode, high VI lubricating oil called VHDC are produced.   In this paper, at first, the advantages of high VI lubricating oil are described. And then it is announced that NMOC and NMPRC have developed a new generation of HDC catalyst with higher cracking activity, higher middle distillate selectivity and longer life than the other commercial HDC catalysts. In addition to those properties, the catalyst is able to yield high VI lubricating oil as well.

  11. Determinan Kepuasan Pelanggan Pada Produk Pertamina Lubricants

    Berto Mulia Wibawa


    Full Text Available Determinants of Customer Satisfaction at Pertamina's Lubricants ProductLubricant industry is one of the strategic industries in around the world. The potential of the lubricant industry in Indonesia grows rapidly along with the increasing demand and the number of a vehicle from year to year. This study aims to analyze factors that influencing customer satisfaction Pertamina Lubricants product and measure how far the customer satisfaction level of its product. This study observed eight categories of Pertamina Lubricants product, with quota sampling technique where each category of the product taken 30 samples, so the total number of the sample are 240 respondents. Multiple linear regression and customer satisfaction index were used in this study. The study finds brand popularity has the most significant effect on customer satisfaction, followed by price and durability. Customer satisfaction level stands at 78 percent, which means belongs in the satisfied category. Managerial implications of this study provide strategies for Pertamina Lubricants to improve their business performance and to increase the level of customer satisfactionDOI:  10.15408/ess.v7i1.4309  

  12. Foaming characteristics of refigerant/lubricant mixtures

    Goswami, D.Y.; Shah, D.O.; Jotshi, C.K.; Bhagwat, S.; Leung, M.; Gregory, A.


    The air-conditioning and refrigeration industry has moved to HFC refrigerants which have zero ozone depletion and low global warming potential due to regulations on CFC and HCFC refrigerants and concerns for the environment. The change in refrigerants has prompted the switch from mineral oil and alkylbenzene lubricants to polyolester-based lubricants. This change has also brought about a desire for lubricant, refrigerant and compressor manufacturers to understand the foaming properties of alternative refrigerant/ lubricant mixtures, as well as the mechanisms which affect these properties. The objectives of this investigation are to experimentally determine the foaming absorption and desorption rates of HFC and blended refrigerants in polyolester lubricant and to define the characteristics of the foam formed when the refrigerant leaves the refrigerant/ lubricant mixture after being exposed to a pressure drop. The refrigerants being examined include baseline refrigerants: CFC-12 (R-12) and HCFC-22 (R-22); alternative refrigerants: HFC-32 (R-32), R-125, R-134a, and R-143a; and blended refrigerants: R-404A, R-407C, and R-410A. The baseline refrigerants are tested with ISO 32 (Witco 3GS) and ISO 68 (4GS) mineral oils while the alternative and blended refrigerants are tested with two ISO 68 polyolesters (Witco SL68 and ICI RL68H).

  13. Evaluation of selected micronized poloxamers as tablet lubricants.

    Desai, D; Zia, H; Quadir, A


    The primary objective of this study was to compare the lubrication properties of micronized poloxamer 188 (Lmicrotrol micro 68) and micronized poloxamer 407 (Lmicrotrol micro 127) with certain conventional lubricants such as magnesium stearate and stearic acid. The secondary objective was to use these micronized poloxamers as water-soluble tablet lubricants in preparation of effervecsent tablets. The results showed that these micronized poloxamers have superior lubrication properties compared with stearic acid, with no negative effect on tablet hardness, friability, disintegration, or dissolution. Moreover, lubricant mixing time had no significant effect on tablet properties when poloxamers were used as lubricants. Effervescent tablets also were produced successfully using micronized poloxamers as lubricants. The micronized poloxamers had a better lubrication effect in comparison with that of water-soluble lubricant l-leucine.

  14. 基于Solid Works注塑模具的塑件结构设计%Construction Design of Plastics Mould Part Based on Solid Works

    赵素渊; 李爱军


    注塑成型方法是制造塑料制品的一个最主要途径.模具是注塑成型必需的设备.介绍了采用Solid Works软件进行模具设计的方法和相关术语,总结了注塑模具设计的过程,提出了注塑模具零件结构设计的规律和设计原则.

  15. Surface films and metallurgy related to lubrication and wear. Ph.D. Thesis - Tokyo Inst. of Technology

    Buckley, D. H.


    The nature of the tribological surface is identified and characterized with respect to adhesion, friction, wear, and lubricating properties. Surface analysis is used to identify the role of environmental constituents on tribological behavior. The effect of solid to solid interactions for metals in contact with metals, ceramics, semiconductors, carbons, and polymers is discussed. The data presented indicate that the tribological surface is markedly different than an ideal solid surface. The environment is shown to affect strongly the behavior of two solids in contact. Results also show that small amounts of alloying elements in base metals can alter markedly adhesion, friction, and wear by segregating to the solid surface.

  16. Energy Dissipation and Apparent Viscosity of Semi-solid Metal during Rheological Processes Part Ⅱ: Apparent Viscosity


    This study investigated the rheological properties of semi-solid metal. An analytical model of apparent viscosity was built up based on analysis of energy dissipation during rheological processes such as slurry preparing,delivering and model filling. The rheological properties of SSM (semi-solid metal) slurry was described by an analytical model in terms of microstructural parameters, which consist of effective solid fraction, particle size and shape, and flow parameters such as mean velocity, fluctuant velocity and relative velocity between liquid and solid phase. The model was verified in the experiment of A356 alloys with a coaxial double-bucket rheometer. And the maximum relative error between the theoretical value and measured one is less than 10%.The results of experiment and theoretical calculation also indicate that the microstructural parameters and flow parameters are two major factors that affect the apparent viscosity of semi-solid alloys, and fluctuant velocity and relative velocity between liquid and solid phase are the key factors to distinguish between steady and transient rheological properties.

  17. Intraurethral lubricants: a critical literature review and recommendations.

    Tzortzis, Vassilios; Gravas, Stavros; Melekos, Michel M; de la Rosette, Jean J


    In current clinical practice, lidocaine gel is widely used as a local anesthetic lubricant before various forms of transurethral instrumentation. Over the past few years, the value of local anesthesia during urethral catheterization and flexible or rigid cystoscopy has been questioned. Strong data are lacking, and the results from the different studies are contradictory. As a result, the correct use of the intraurethral gels is, for the most part, left to individual preference. The purpose of this review is to provide an overview of the characteristics of the intraurethral gels, to assess the effectiveness, and to define evidence-based indications for their use.

  18. olidWorks secondary development in application and research in the design of mechanical parts%SolidWorks二次开发在机械零件设计中的应用与研究



    SolidWorks secondary development plays an important role in the mechanical parts design, reasonable use SolidWorks secondary development technology can improve the performance of mechanical parts. This paper analyses the structure design of the machine parts,and with SolidWorks in coupling structure design as an example,the application of SolidWorks software system is introduced in this paper in the concrete application in the process of the machine parts design.%本文分析了机器零件的结构设计,并以SolidWorks在联轴器的结构设计中的应用为例,介绍SolidWorks软件系统在机器零件设计过程中的具体运用.

  19. Dispersants in an organic medium: synthesis and physicochemical study of dispersants for fuels and lubricants; Dispersants en milieu organique: synthese et etude physicochimique de dispersants pour carburants et lubrifiants

    Dubois-Clochard, M.C.


    Carbonaceous deposits coming from the fuel and the lubricant are known to form over time at critical locations in an engine. In general, the deposits have an adverse effect on four functional areas which are the fuel metering system, the intake system, the lubrication system and the combustion chambers. These deposits can degrade vehicle performance and drive-ability, reduce fuel economy, increase fuel consumption and pollutant emissions and may lead to the destruction of the engine. In order to remedy these problems, detergent-dispersant additives are used in fuels and lubricants to avoid or decrease deposit adhesion on metallic surfaces and prevent from deposit aggregation. These products are mainly polymer surfactants and in this work, poly-iso-butenyl-succinimide of different structures have been studied. Firstly, 'comb like' polymers have been synthesized. Then they have been compared to classical di-bloc additives in terms of performance and action mechanism. These additives are adsorbed from their hydrophilic polyamine part on the acidic functions of the carbon black surface chosen as an engine deposit model and on the aluminium oxide function of an aluminium powder chosen as an engine wall model. The adsorption increases with temperature on the two solids. Their affinity with the solid surface increases with the length of the hydrophilic part. In the same way, changing the di-bloc structure for a comb like one lead to a better adsorption. At low concentration, it has been shown that the adsorption phenomenon was irreversible, due to the polymer structure of the polar part. Depending on the space required by the hydrophilic part on the solid surface, a more of less dense monolayer is formed. At higher concentrations, an important increase of the adsorbed amount appears. This phenomenon is totally reversible showing that the interactions additive / additive are weak. The dispersing efficiency of a comb like structure is better than a di-bloc one as

  20. Lubricant for clean rolling: Escapee oil particles keep cold rolling steel mills lubricated

    Van De Graaf, A.


    One of the unique selling points of the Corus steel mills at IJmuiden is the quality of the steel they produce. The lubrication used during the last production stage is one of the factors that determine how clean and smooth the steel will emerge from the mill. The usual lubricant consists of an emul

  1. Reduced Need of Lubricity Additives in Soybean Oil Blends Under Boundary Lubrication Conditions

    Converging prices of vegetable oils and petroleum, along with increased focus on renewable resources, gave more momentum to vegetable oil lubricants. Boundary lubrication properties of four Extreme Pressure (EP) additive blends in conventional Soy Bean Oil (SBO) and Paraffinic Mineral Oil (PMO) of ...

  2. Studies on micro plasto hydrodymic lubrication in metal forming

    Bay, Niels; Bech, Jakob Ilsted; Andreasen, Jan Lasson


    The influence of work piece surface topography on friction and lubrication and final surface quality in metal forming operations is well known and has been pointed out by many researchers, see Schey (1983) and Bay and Wanheim (1990). This is especially the case when liquid lubrication is applied...... to be trapping of lubricant in closed pockets in the surface and subsequent permeation of the viscous lubricant into areas of contact between the flattened work piece asperities and the tool surface. They named this lubrication mechanism MicroPlasto HydroDynamic Lubrication (MPHDL). In studies of plane strip...

  3. Effect of Die Wall Lubrication on Warm Compaction Powder Metallurgy


    Die wall lubrication was applied on warm compaction powder metallurgy in hope to reduce the concentration level of the admixed lubricant since lubricant is harmful to the mechanical property of the sintered materials. Iron-based samples were prepared by die wall lubricated warm compaction at 135 ℃ and 175 ℃, using polytetrafluoroethylene (PTFE) emulsion as die wall lubricant. A compacting pressure of 700 MPa and 550 MPa were used. The admixed lubricant concentration ranging from 0 to 0.6 wt.% was used in th...

  4. Lubrication study for Single Point Incremental Forming of Copper

    Jawale, Kishore; Ferreira Duarte, José; Reis, Ana; Silva, M. B.


    In conventional machining and sheet metal forming processes, in general, lubrication assists to increase the quality of the final product. Similarly it is observed that there is a positive effect of the use of lubrication in Single point incremental forming, namely in the surface roughness. This study is focused on the investigation of the most appropriate lubricant for incremental forming of copper sheet. The study involves the selection of the best lubricant from a range of several lubricants that provides the best surface finishing. The influence of the lubrication on other parameters such as the maximum forming angle, the fracture strains and the deformed profile are also studied for Copper.

  5. Scale-up model describing the impact of lubrication on tablet tensile strength.

    Kushner, Joseph; Moore, Francis


    Lubrication of 2:1 and 1:1 blends of microcrystalline cellulose and spray-dried lactose or dibasic calcium phosphate (DCP) with 0.33% or 1% magnesium stearate, as model free-flowing pharmaceutical formulations, was performed in rotary drum blenders. Blender process parameters examined in this study included type (Bin, V, and Turbula), volume (0.75-Quart to 200-L), fraction of headspace in the blender after the blend is loaded (30-70%), speed (6-202 rpm), and time (up to 225 min). Based on analysis of the experimental data, the following model for the impact of the lubrication process on tablet tensile strength at 0.85 solid fraction, TS(SF=0.85), was obtained, TS(SF=0.85)=TS(SF=0.85,0) [βexp(-γ×V(1/3)×F(headspace)×r)+(1-β)], where V is blender volume, F(headspace) is the headspace fraction, r is the number of revolutions (i.e. speed × time), TS(SF=0.85,0) is the initial tensile strength of the blend, β is the sensitivity of the blend to lubrication, and γ is the lubrication rate constant of the formulation. This model can be used to maintain tensile strength during scale-up, by ensuring that (V(1/3)F(headspace)r)(1)=(V(1/3)F(headspace)r)(2). The model also suggests that formulations with DCP are less sensitive to lubrication and more slowly lubricated than formulations with spray-dried lactose (i.e. smaller β and γ values).

  6. Study on the applicability of a precise, accurate method for rapid evaluation of engine and lubricant performance. [determination of wear metal in used lubricating oils

    Kinard, J. T.


    The development of a procedure for obtaining data related to wear metal determinations in used lubricants is discussed. The procedure makes it possible to obtain rapid, simultaneous determinations of a number of wear metals at levels of parts per thousand to low parts per billion using a small amount of sample. The electrode assembly and instrumentation used in the process are described. Samples of data obtained from tests conducted under controlled conditions are tabulated.

  7. Regeneration of used lubricating oils

    Adler, N.; Adler, E.; Cismic, V.; Prohaska, B.; Yabar-Mejia, B.


    In Yugoslavia in 1985, it is planned that 150,000 tons/year will be recycled, at a consumption of 317,000 tons/year of lubricating oils. The technology is described for recycling waste oil by the traditional method of sulfuric acid cleaning with precleaning by bleaching clay and modern waste oil recycling processes, based on using selective solvents and hydraulic cleaning. The technological features are examined of performing individual recycling stages; dehydration, purification by sulfuric acid, propane, and a mixture of propanol-2, methyl ethyl ketone and butanol-1, propanol-2 and butanol-1, hydraulic cleaning, rectification, precleaning by bleaching clay, and addition of additives. It is noted that the unit capacity of old waste oil recycling plants using sulfuric acid and bleaching clay, built in Zaqreb, Modrits and Maribor, does not exceed 10,000 tons/year, while the new plant for deasphalting by propane and hydraulic cleaning built in Belgrad is rated to recycle 25,000 tons/year of oil (the total capacity of the oil recycling plants has reached 55,000 tons/year). A comparison is made of the economic indices of operation of the old and new waste oil recycling plants. Initial data, the technique and results of economic calculations are given. It is established that modern waste oil recycling plants are more profitable than antiquated ones with a low unit capacity. The profitability of the plants will grow with an increase in the capacity and in oil prices.

  8. Determination of service life of aviation lubricants

    Kuznetsov, V.G.; Novosartov, G.T.; Echin, A.I.; Bakunin, V.N.


    A method of evaluating the quality of expensive lubricants was developed based on determination of thermo-oxidative stability on a TSM-1 apparatus. This allowed measurement of the content of additives and qualitative properties associated with them during oxidation under laboratory conditions. By developing graphs showing dependence of operating properties sharply degrade was determined. This minimum additive content became the criterion for assessing the working capability of the lubricant and determining the limiting length of its service. Thus, for lubricant B-3V, the most important operating characteristics are thermooxidative stability and critical loading. Samples were tested for the additives PODFA and kaptaks and for indicators of antioxidative and antiseizing properties. Experiments showed little change in characteristics during 10 h of oxidation. Laboratory tests showed that the critical loading began to drop when the kaptaks level fell below 0.2%, so this was taken as the minimal acceptable level. Similarly, for lubricant IPM-10, the most important operating property is its thermo-oxidative stability. Tests showed that indicators of thermo-oxidative stability all began to fall when the antioxidative additive fell below 0.1%. This approach allows rapid determination of service criteria for any aviation lubricant with critical additives. In a practical test, B-3V lubricant had been changed in the MI-8 helicopter every 200-300 h, although its kaptaks level was still 0.65%; even at 900 hours it had fallen to only 0.36%. This would allow the service life to be tripled, a conclusion verified by determination of physicochemical and operating properties of the lubricant at that point. 4 references, 2 figures.

  9. Hexagonal boron nitride as a tablet lubricant and a comparison with conventional lubricants.

    Uğurlu, Timuçin; Turkoğlu, Murat


    The objective of this study was to investigate the lubrication properties of hexagonal boron nitride (HBN) as a new tablet lubricant and compare it with conventional lubricants such as magnesium stearate (MGST), stearic acid (STAC), and glyceryl behenate (COMP). Tablets were manufactured on an instrumented single-station tablet press to monitor lower punch ejection force (LPEF) containing varied lubricants in different ratio (0.5, 1, 2%). Tablet crushing strength, disintegration time and thickness were measured. Tensile strength of compacted tablets were measured by applying a diametrical load across the edge of tablets to determine mechanical strength. The deformation mechanism of tablets was studied during compression from the Heckel plots with or without lubricants. MGST was found to be the most effective lubricant based on LPEF-lubrication concentration profile and LPEF of HBN was found very close to that of MGST. HBN was better than both STAC and COMP. A good lubrication was obtained at 0.5% for MGST and HBN (189 and 195N, respectively). Where COMP and STAC showed 20 and 35% more LPEF compare to that of MGST (239 and 288N, respectively). Even at the concentration of 2% COMP and STAC did not decrease LPEF as much as 0.5% of MGST and HBN. Like all conventional lubricants the higher the concentration of HBN the lower the mechanical properties of tablets because of its hydrophobic character. However, this deterioration was not as pronounced as MGST. HBN had no significant effect on tablet properties. Based on the Heckel plots, it was observed that after the addition of 1% lubricant granules showed less plastic deformation.

  10. Fault weakening and earthquake instability by powder lubrication

    Reches, Z.; Lockner, D.A.


    Earthquake instability has long been attributed to fault weakening during accelerated slip1, and a central question of earthquake physics is identifying the mechanisms that control this weakening2. Even with much experimental effort2-12, the weakening mechanisms have remained enigmatic. Here we present evidence for dynamic weakening of experimental faults that are sheared at velocities approaching earthquake slip rates. The experimental faults, which were made of room-dry, solid granite blocks, quickly wore to form a fine-grain rock powder known as gouge. At modest slip velocities of 10-60mms-1, this newly formed gouge organized itself into a thin deforming layer that reduced the fault's strength by a factor of 2-3. After slip, the gouge rapidly 'aged' and the fault regained its strength in a matter of hours to days. Therefore, only newly formed gouge can weaken the experimental faults. Dynamic gouge formation is expected to be a common and effective mechanism of earthquake instability in the brittle crust as (1) gouge always forms during fault slip5,10,12-20; (2) fault-gouge behaves similarly to industrial powder lubricants21; (3) dynamic gouge formation explains various significant earthquake properties; and (4) gouge lubricant can form for a wide range of fault configurations, compositions and temperatures15. ?? 2010 Macmillan Publishers Limited. All rights reserved.

  11. Lubrication approximation in completed double layer boundary element method

    Nasseri, S.; Phan-Thien, N.; Fan, X.-J.

    This paper reports on the results of the numerical simulation of the motion of solid spherical particles in shear Stokes flows. Using the completed double layer boundary element method (CDLBEM) via distributed computing under Parallel Virtual Machine (PVM), the effective viscosity of suspension has been calculated for a finite number of spheres in a cubic array, or in a random configuration. In the simulation presented here, the short range interactions via lubrication forces are also taken into account, via the range completer in the formulation, whenever the gap between two neighbouring particles is closer than a critical gap. The results for particles in a simple cubic array agree with the results of Nunan and Keller (1984) and Stoksian Dynamics of Brady etal. (1988). To evaluate the lubrication forces between particles in a random configuration, a critical gap of 0.2 of particle's radius is suggested and the results are tested against the experimental data of Thomas (1965) and empirical equation of Krieger-Dougherty (Krieger, 1972). Finally, the quasi-steady trajectories are obtained for time-varying configuration of 125 particles.

  12. Lubrication Mechanism of Micro/Nano-particles on Sialon

    ZHANGWen-guang; LIUWei-min


    The tribologieal properties of Sialon sliding against MS152100 steel bull under the lubrication of solid particle additives,, as micro-borate particle and nanoPbS particle, were evaluated by a SRV ball-on-disctest rig. The chemical composition of the worn surface was characterized by X-ray pohotoelectron spectroscopy(XPS).The morphologies of the wont surfaces of Sialon were analyzed by scanning electron microscopy (SEM).The results show that the particles can redace the friction coefficient of the pairs and the wear volume of Siulon significantly. The wear resitaace of micro-borate is superior to that of nano-PbS while the friction-reducing abilityof PBS is better than that of borate. According to the XPS and SEM results, the wear resistance of Pbs is mainly depended on the tribochemical film mainly composed of PbSO4, which deposited on the wont surface with goodbonding strength. No tribochemical reaction or deposited film was detected or observed on the worn surface of Sialon under the lubrication of borate, uidieating that the possible physically deposited film generated from micro particle can also greatly reduce the wear volume of Sialon, though the friction reducing ability of which is inferior to that of nano PbS particle.

  13. Frequency Response Analysis of an Actively Lubricated Rotor/Tilting-Pad Bearing System

    Nicoletti, Rodrigo; Santos, Ilmar


    In the present paper, the dynamic response of a rotor supported by an active lubricated tilting-pad bearing is investigated in the frequency domain. The theoretical part of the investigation is based on a mathematical model obtained by means of rigid body dynamics. The oil film forces are inserte...

  14. Powder lubrication of faults by powder rolls in gouge zones

    Chen, X.; Madden, A. S.; Reches, Z.


    Powder-lubrication by fault gouge can be an effective mechanism of dynamic weakening of faults (Reches & Lockner, 2010); however, the physical mechanisms of this lubrication are poorly understood. While the flow of coarse-grained (> 100 μm) materials, e.g. glass beads or quartz sand, was extensively studied, the flow of fine-grained (nano-powders, have remained enigmatic. We report here experimental results of a new efficient mechanism for powder lubrication. We conducted friction tests on high-velocity rotary shear apparatus (Reches & Lockner, 2010). Two types of experimental faults were tested: (1) faults made of solid, igneous rocks (granite, tonalite and diorite); and (2) fault-zones made of 2-3 mm thick layer of granular materials (oolites, calcite or gypsum) sheared in a confined cell. We performed 21 runs with total slip of 0.14-13 m, normal stress of 1.2-14.5 MPa, slip velocity of 0.012-0.97 m/s. The ultra-microscopic (SEM and AFM) analysis of the experimental slip surfaces revealed two outstanding features in 17 out of the 21 experiments: (1) localized fault-slip along Principal Slip Zones (PSZs) that are composed of a dense, shiny, cohesive crust, 0.5-1 micron thick, that overlaid a porous substrate, and (2) elongated rolls composed of gouge-powder into three-dimensional structures of closely-packed powder grains, (20-50 nm in size). The rolls are cylindrical, 0.75-1.4 micron wide, and 1.7-30 micron long, with smooth outer surface, and laminated, concentric layers of compacted grains. The rolls were exclusively found on the PSZs. Many rolls were destroyed fracturing and smearing on the PSZ, suggesting that the rolls underwent a life cycle of formation and destruction. Significant macroscopic friction reduction was measured in experiments with observed rolls, and no (or minor) friction reduction in the four experiments without rolls. The final, reduced friction coefficients have a general reciprocal relation to the rolls surface coverage, suggesting that

  15. Electrowetting on dielectrics on lubricating fluid based slippery surfaces with negligible hysteresis

    Barman, Jitesh; Nagarajan, Arun Kumar; Khare, Krishnacharya


    Low voltage electrowetting on dielectrics on substrates with thin layer of lubricating fluid to reduce contact angle hysteresis is reported here. On smooth and homogeneous solid surfaces, it is extremely difficult to reduce contact angle hysteresis (contact angle difference between advancing and receding drop volume cycle) and the electrowetting hysteresis (contact angle difference between advancing and receding voltage cycle) below 10{\\deg}. On the other hand, electrowetting hysteresis on ro...

  16. Lubrication regimes in lumbar total disc arthroplasty.

    Shaheen, A; Shepherd, D E T


    A number of total disc arthroplasty devices have been developed. Some concern has been expressed that wear may be a potential failure mode for these devices, as has been seen with hip arthroplasty. The aim of this paper was to investigate the lubrication regimes that occur in lumbar total disc arthroplasty devices. The disc arthroplasty was modelled as a ball-and-socket joint. Elastohydrodynamic lubrication theory was used to calculate the minimum film thickness of the fluid between the bearing surfaces. The lubrication regime was then determined for different material combinations, size of implant, and trunk velocity. Disc arthroplasties with a metal-polymer or metal-metal material combination operate with a boundary lubrication regime. A ceramic-ceramic material combination has the potential to operate with fluid-film lubrication. Disc arthroplasties with a metal-polymer or metal-metal material combination are likely to generate wear debris. In future, it is worth considering a ceramic-ceramic material combination as this is likely to reduce wear.

  17. Thermal activation in boundary lubricated friction

    Michael, P.C. [Francis Bitter National Magnet Lab. and Dept. of Mechanical Engineering, Massachusetts Inst. of Tech., Cambridge, MA (United States); Rabinowicz, E. [Francis Bitter National Magnet Lab. and Dept. of Mechanical Engineering, Massachusetts Inst. of Tech., Cambridge, MA (United States); Iwasa, Y. [Francis Bitter National Magnet Lab. and Dept. of Mechanical Engineering, Massachusetts Inst. of Tech., Cambridge, MA (United States)


    The friction coefficients for copper pairs lubricated with fatty acids and fluorinated fatty acids have been measured over a wide range of sliding speeds and temperatures. Sliding speeds in the range 10{sup -7}-10{sup -2} m s{sup -1} and temperatures in the range 4.2-300 K were used. The friction coefficients near 300 K are generally low and increase with sliding speed, while the friction coefficients at low temperatures are markedly higher and relatively independent of velocity. Each lubricant`s friction vs. velocity behavior over the temperature range 150-300 K can be described by a friction-velocity master curve derived from a thermal activation model for the lubricant`s shear strength. The activation energies deduced from this friction model are identical to those obtained in the same temperature range for a vibrational mode associated with low temperature mechanical relaxations in similarly structured polymers. These results suggest that thermally activated interfacial shear is responsible for the fatty acids` positive-sloped friction vs. velocity characteristics at low sliding speeds near room temperature. (orig.)

  18. Nanoscale Organic−Inorganic Hybrid Lubricants

    Kim, Daniel


    Silica (SiO2) nanoparticles densely grafted with amphiphilic organic chains are used to create a family of organic-inorganic hybrid lubricants. Short sulfonate-functionalized alkylaryl chains covalently tethered to the particles form a dense corona brush that stabilizes them against aggregation. When these hybrid particles are dispersed in poly-α-olefin (PAO) oligomers, they form homogeneous nanocomposite fluids at both low and high particle loadings. By varying the volume fraction of the SiO2 nanostructures in the PAO nanocomposites, we show that exceptionally stable hybrid lubricants can be created and that their mechanical properties can be tuned to span the spectrum from simple liquids to complex gels. We further show that these hybrid lubricants simultaneously exhibit lower interfacial friction coefficients, enhanced wear and mechanical properties, and superior thermal stability in comparison with either PAO or its nanocomposites created at low nanoparticle loadings. Profilometry and energy dispersive X-ray spectroscopic analysis of the wear track show that the enhanced wear characteristics in PAO-SiO2 composite lubricants originate from two sources: localization of the SiO2 particles into the wear track and extension of the elastohydrodynamic lubrication regime to Sommerfeld numbers more than an order of magnitude larger than for PAO. © 2011 American Chemical Society.

  19. Vegetable oil base stocks for lubricants

    Garces, R.; Martinez-Force, E.; Salas, J.


    The use of vegetable biodegradable base stocks for lubricant oils present several advantages over the much more extended mineral bases. These advantages refer to biodegradability, a renewable feedstock of local production, lubricant and viscosity index and lower costs than synthetic lubricant bases. Despite these benefits, their use in industry and motor vehicles is not yet extensive due their lower stability and higher pour points. Vegetable oils are esters of fatty acids and glycerol, and their physicochemical properties rely mainly on the composition of their acyl moieties. Thus, to assure the maximum levels of stability while maintaining acceptable behavior at low temperatures, monounsaturated fatty acids are preferred for this purpose. The presence of natural antioxidants also improves the properties of these vegetable based stocks as lubricants. These oils usually require additives to improve their viscosity value, oxidative stability and properties at low temperatures. In the present work, the different sources of vegetable oils appropriate for bio lubricant production were reviewed. Their properties and the future improvement of the oil bases, oil based stock production, uses and additives are discussed. (Author).

  20. Application of a Biodegradable Lubricant in a Diesel Vehicle

    Schramm, Jesper


    The IEA Advanced Motor Fuels Agreement has initiated this project concerning the application of biodegradable lubricants to diesel and gasoline type vehicles. Emission measurements on a chassis dynamometer were carried out. The purpose of these measurements was to compare the emissions of CO, CO2......, NOx, THC, PM, lubricant-SOF and PAH from one diesel and one gasoline type vehicle using biodegradable lubricants and conventional lubricants. This paper describes the results of the experiments with the diesel type vehicle only. Lubricant consumption and fuel consumption are other important parameters...... lubricant, compared to the reference lubricant, was dependent on the driving pattern -the lubricant was the main contributor to the soluble organic fraction of the particulates emitted, only biodiesel gave a contribution from the fuel -a slightly higher fuel consumption and NOx emission was noticed...

  1. Gastrointestinal behavior of itraconazole in humans - Part 1: Supersaturation from a solid dispersion and a cyclodextrin-based solution.

    Brouwers, Joachim; Geboers, Sophie; Mols, Raf; Tack, Jan; Augustijns, Patrick


    This study evaluated the fasted state gastrointestinal behavior of the lipophilic drug itraconazole, orally administered to healthy volunteers as either a solid dispersion (Sporanox(®) capsules) or a cyclodextrin-based solution (Sporanox(®) solution). Following intake of the drug products, gastric and duodenal fluids were aspirated and analyzed for itraconazole concentration, total content and solubilizing capacity. Release of itraconazole from the solid dispersion generated high and metastable supersaturated levels in the stomach, but the dissolved fraction in the duodenum remained extremely low (median 2.5%). After intake of the itraconazole solution, precipitation was limited in the stomach but pronounced in the small intestine. Still, the dissolved fraction of itraconazole in the duodenum (median 38%) appeared much higher than after intake of the solid dispersion, possibly explaining the improved absorption of itraconazole from the solution. As for the solid dispersion, the absorption-enabling ability of the solution appeared mainly related to increased intraluminal concentrations by means of supersaturation. Cyclodextrin-based solubilization of itraconazole occurred only in the case of limited intraluminal dilution, but did not further enhance itraconazole absorption. The obtained data will help to understand critical aspects of supersaturating drug delivery systems and act as direct reference for the optimization of in vitro simulation tools for gastrointestinal drug behavior. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Management of industrial solid residues; Gerenciamento de residuos solidos industriais



    This chapter gives an overview on the management of industrial solid wastes, approaching the following subjects: classification of industrial solid residues; directives and methodologies for the management of industrial solid residues; instruments for the management of industrial solid residues; handling, packing, storage and transportation; treatment of industrial solid residues; final disposal - landfill for industrial residues; the problem of treatment and final disposer of domestic garbage in Brazil; recycling of the lubricant oils used in brazil; legislation.

  3. Evaluation of minimum quantity lubrication grinding with nano-particles and recent related patents.

    Li, Changhe; Wang, Sheng; Zhang, Qiang; Jia, Dongzhou


    In recent years, a large number of patents have been devoted to developing minimum quantity lubrication (MQL) grinding techniques that can significantly improve both environmentally conscious and energy saving and costeffective sustainable grinding fluid alternatives. Among them, one patent is about a supply system for the grinding fluid in nano-particle jet MQL, which produced MQL lubricant by adding solid nano-particles in degradable grinding fluid. The MQL supply device turns the lubricant to the pulse drops with fixed pressure, unchanged pulse frequency and the same drop diameter. The drops will be produced and injected in the grinding zone in the form of jet flow under high pressure gas and air seal. As people become increasingly demanding on our environment, minimum quantity lubrication has been widely used in the grinding and processing. Yet, it presents the defect of insufficient cooling performance, which confines its development. To improve the heat transfer efficiency of MQL, nano-particles of a certain mass fraction can be added in the minimum quantity of lubricant oil, which concomitantly will improve the lubrication effects in the processing. In this study, the grinding experiment corroborated the effect of nano-particles in surface grinding. In addition, compared with other forms of lubrication, the results presented that the grinding force, the friction coefficient and specific grinding energy of MQL grinding have been significantly weakened, while G ratio greatly rose. These are attributed to the friction oil-film with excellent anti-friction and anti-wear performance, which is generated nano-particles at the wheel/workpiece interface. In this research, the cooling performance of nano-particle jet MQL was analyzed. Based on tests and experiments, the surface temperature was assayed from different methods, including flood lubricating oil, dry grinding, MQL grinding and nano-particle jet MQL grinding. Because of the outstanding heat transfer

  4. Lubricant Biodegradation Enhancers:Designed Chemistry and Engineered Technology

    Chen Boshui; Gao Lingyue; Fang Jianhua; Zhang Nan; Wu Jiang; Wang Jiu


    In recent decades, a growing worldwide trend of developing the biodegradable lubricants has been prevailing to form a speciifc ifeld of green chemistry and green engineering. Enhancement of biodegradability of unreadily biodegradable petroleum-based lubricants has as such become an urgent must. For over a decade the authors have been focusing on the im-provement of biodegradability of unreadily biodegradable lubricants such as petroleum-based lubricating oils and greases. A new idea of lubricant biodegradation enhancer was put forward by the authors with the aim to stimulate the biodegradation of unreadily biodegradable lubricants by incorporating the enhancer into the lubricants in order to turn the lubricants into greener biodegradable ones and to help in situ bioremediation of lubricant-contaminated environment. This manuscript sum-marizes our recent efforts relating to the chemistry and technology of biodegradation enhancers for lubricants. Firstly, the chemistry of lubricant biodegradation enhancers was designed based on the principles of bioremediation for the treatment of hydrocarbon contaminated environment. Secondly, the ability of the designed biodegradation enhancers for increasing the biodegradability of unreadily biodegradable industrial lubricants was investigated through biodegradability evaluation tests, microbial population analysis, and biodegradation kinetics modeling. Finally, the impact of biodegradation enhancers on some crucial performance characteristics of lubricants such as lubricity and oxidation stability was tested via tribological evaluation and oxidation determinations. Our results have shown that the designed chemistry of nitrogenous and/or phos-phorous compounds such as lauroyl glutamine, oleoyl glycine, oleic diethanolamide phosphate and lauric diethanolamide borate was outstanding in boosting biodegradation of petroleum-based lubricants which was ascribed to increase the micro-bial population and decrease the oil-water interfacial

  5. Molecular rheological analysis on binary blends of perfluoropolyether lubricants

    Seung Chung, Pil; Hari Vemuri, Sesha; Park, Sejoon; Jhon, Myung S.


    The molecular rheology of PFPE becomes critically important in designing optimal lubricants that control the friction/wear and air-bearing by tuning elastic or viscous shear/elongation deformations, which affect the performance and reliability of the hard disk drive. In this paper, we examine the rheological responses of nano blended PFPEs including storage (elastic) and loss (viscous) moduli (G' and G″), by monitoring the time-dependent-stress-strain relationship via non-equilibrium molecular dynamics simulations. By introducing binary blend of nonfunctional and functional PFPEs, we control the degree of liquid/solid-like behavior using the rheology as a complementary tool for design criteria by tuning molecular conformation and diffusion with nano blend ratio.

  6. An innovation integrated approach to testing motorcycle drive chain lubricants

    Lee, P.M.; Priest, M.


    An innovative integrated approach to the testing and comparison of motorcycle drive chain lubricants is presented. This is a novel way of testing the lubrication by using loaded operating chains and sprockets. A test rig has been designed to operate chains and sprockets in a clean environment and allow direct comparison between different lubricants. The advantage of this method over previous techniques is that it allows the differentiation of lubricants in a more controlled operating environm...

  7. Shell Becomes 3rd Largest Lubricants Provider in China


    @@ Royal Dutch Shell Group has bought a 75percent stake in China's largest privately owned lubricant oil company Tongyi, making it the third largest in China's lubricants market, based on the recent report from the Chinese news media."The transaction will increase Shell's global finished lubricants volume by 8 percent, giving it approximately 16 percent of the global branded finished lubricants market," the company said in a statement.

  8. Testing of environmentally friendly lubricants for sheet metal forming

    Bay, Niels; Olsson, David Dam; Andreasen, Jan Lasson


    the authors have especially been involved in the development of a system of test methods for sheet metal forming and in testing of friction and limits of lubrication of new, environmentally friendly lubricants. An overview of the developed tests is presented together with selected results....... Kingdom, Finland, Poland, Slovenia, Spain and Denmark. Partners in the programmes represent lubricant developers, testing experts and industrial end users as well as numerical modelling experts simulating fundamental lubrication mechanisms and computing basic process parameters. In these programmes...

  9. Numerical Simulation of Piston Ring Lubrication

    Felter, Christian Lotz


    This paper describes a numerical method that can be used to model the lubrication of piston rings. Classical lubrication theory is based on the Reynolds equation which is ap- plicable to confined geometries and open geometries where the flooding conditions are known. Lubrication of piston rings...... is extended to include also the oil film outside the piston rings. The numerical model consists of a 2D free surface code that solves the time dependent compressible Navier-Stokes equations. The equations are cast in Lagrangian form and discretized by a meshfree moving least squares method using the primitive......, however, fall outside this category of problems since the piston rings might suffer from starved running conditions. This means that the com- putational domain where Reynold equation is applicable (including a cavitation criteria) is unknown. In order to overcome this problem the computational domain...

  10. Micro-droplets lubrication film thickness dynamics

    Huerre, Axel; Theodoly, Olivier; Cantat, Isabelle; Leshansky, Alexander; Valignat, Marie-Pierre; Jullien, Marie-Caroline; MMN Team; LAI Team; IPR Team; Department of Chemical Engineering Team


    The motion of droplets or bubbles in confined geometries has been extensively studied; showing an intrinsic relationship between the lubrication film thickness and the droplet velocity. When capillary forces dominate, the lubrication film thickness evolves non linearly with the capillary number due to viscous dissipation between meniscus and wall. However, this film may become thin enough that intermolecular forces come into play and affect classical scalings. We report here the first experimental evidence of the disjoining pressure effect on confined droplets by measuring droplet lubrication film thicknesses in a microfluidic Hele-Shaw cell. We find and characterize two distinct dynamical regimes, dominated respectively by capillary and intermolecular forces. In the former case rolling boundary conditions at the interface are evidenced through film thickness dynamics, interface velocity measurement and film thickness profile.

  11. Solid Lubrication of Laser Grown Fluorinated Diamond Thin Films


    irradiation of laser beam on the substrate surface 2 Schematic diagram showing laser CVD experimental set- up . 27 A single laser beam (YAG or Excimer) was only...0.05 to 0.2 depending upon temperature, environment, load, speed and presence of foreign material. Todate , ultra-low coefficients of friction (0.02...Laser technology for diamond film fabrication is very new and todate only a handful number of publications are available that address directly on the

  12. Antiwear performance and mechanism of an oil-miscible ionic liquid as a lubricant additive.

    Qu, Jun; Bansal, Dinesh G; Yu, Bo; Howe, Jane Y; Luo, Huimin; Dai, Sheng; Li, Huaqing; Blau, Peter J; Bunting, Bruce G; Mordukhovich, Gregory; Smolenski, Donald J


    An ionic liquid (IL) trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate has been investigated as a potential antiwear lubricant additive. Unlike most other ILs that have very low solubility in nonpolar fluids, this IL is fully miscible with various hydrocarbon oils. In addition, it is thermally stable up to 347 °C, showed no corrosive attack to cast iron in an ambient environment, and has excellent wettability on solid surfaces (e.g., contact angle on cast iron lubricating oils. For example, a 5 wt % addition into a synthetic base oil eliminated the scuffing failure experienced in neat oil and, as a result, reduced the friction coefficient by 60% and the wear rate by 3 orders of magnitude. A synergistic effect on wear protection was observed with the current antiwear additive when added into a fully formulated engine oil. Nanostructure examination and composition analysis revealed a tribo-boundary film and subsurface plastic deformation zone for the metallic surface lubricated by the IL-containing lubricants. This protective boundary film is believed to be responsible for the IL's antiscuffing and antiwear functionality.

  13. On the question of whether lubricants fluidize in stick-slip friction.

    Rosenhek-Goldian, Irit; Kampf, Nir; Yeredor, Arie; Klein, Jacob


    Intermittent sliding (stick-slip motion) between solids is commonplace (e.g., squeaking hinges), even in the presence of lubricants, and is believed to occur by shear-induced fluidization of the lubricant film (slip), followed by its resolidification (stick). Using a surface force balance, we measure how the thickness of molecularly thin, model lubricant films (octamethylcyclotetrasiloxane) varies in stick-slip sliding between atomically smooth surfaces during the fleeting (ca. 20 ms) individual slip events. Shear fluidization of a film of five to six molecular layers during an individual slip event should result in film dilation of 0.4-0.5 nm, but our results show that, within our resolution of ca. 0.1 nm, slip of the surfaces is not correlated with any dilation of the intersurface gap. This reveals that, unlike what is commonly supposed, slip does not occur by such shear melting, and indicates that other mechanisms, such as intralayer slip within the lubricant film, or at its interface with the confining surfaces, may be the dominant dissipation modes.

  14. Transparent self-cleaning lubricant-infused surfaces made with large-area breath figure patterns

    Zhang, Pengfei; Chen, Huawei; Zhang, Liwen; Ran, Tong; Zhang, Deyuan


    Nepenthes pitcher inspired slippery lubricant-infused porous surfaces greatly impact the understanding of liquid-repellent surfaces construction and have attracted extensive attention in recent years due to their potential applications in self-cleaning, anti-fouling, anti-icing, etc. In this work, we have successfully fabricated transparent slippery lubricant-infused surfaces based on breath figure patterns (BFPs). Large-area BFPs with interconnected pores were initially formed on the glass substrate and then a suitable lubricant was added onto the surfaces. The interconnected pores in BFPs were able to hold the lubricant liquid in place and form a stable liquid/solid composite surface capable of repelling a variety of liquids. The liquid-repellent surfaces show extremely low critical sliding angles for various liquids, thus providing the surfaces with efficient self-cleaning property. It was also found that the liquid droplets' sliding behaviors on the surfaces were significantly influenced by the tilting angle of the substrate, liquid volume, liquid chemical properties, and pore sizes of the surfaces.

  15. Failure Mechanisms of Air Entrainment in Drop Impact on Lubricated Surfaces

    Pack, Min; Hu, Han; Kim, Dong-Ook; Zheng, Zhong; Stone, Howard; Sun, Ying; Drexel University Team; Princeton University Team


    Lubricated surfaces have recently been introduced and studied due to their potential benefit in various applications. Combining the techniques of total internal reflection microscopy and reflection interference microscopy, we examine the dynamics of an underlying air film upon drop impact on a lubricated substrate. In contrast to drop impact on solid surfaces where asperities cause random breakup of the entraining air film, we report two air film failure mechanisms on lubricated surfaces. In particular, using thin liquid films of high viscosity, we show that air film rupture shifts from a randomly driven to a controlled event. At low Weber numbers (We) the droplet bounces. At intermediate We, the air film fails at the center as the drop top surface crashes downward owing to impact-induced capillary waves; the resulting liquid-liquid contact time is found to be independent of We. In contrast, at high We, the air film failure occurs much earlier in time at the first inflection point of the air film shape away from the drop center, where the liquid-liquid van der Waals interactions become important. The predictable failure modes of the air film upon drop impact sheds light on droplet deposition in applications such as lubricant-infused self-cleaning surfaces. Support for this work was provided by the National Science Foundation under Grant No. CMMI-1401438 to Y.S.

  16. Synthesis of fatty monoester lubricant base oil catalyzed by Fe-Zn double-metal cyanide complex

    Ravindra K Raut; Mehejabeen Shaikh; Srinivas Darbha


    Fatty monoester lubricant base oils as high as 96.7 mol% were prepared by reacting methyl oleate with long-chain alcohols viz., 2-ethyl-1-hexanol (C8−OH), 1-decanol (C10OH) and 1-dodecanol (C12OH) in the presence of a solid Fe-Zn double-metal cyanide (DMC) complex catalyst. Unlike many other acid catalysts, DMC doesn't produce undesired ether side products. The catalyst was reusable in four recycling experiments with little loss in catalytic activity and ester yield. The long-chain esters prepared in the study have the desired physical properties for their application as lubricant base oils.

  17. Entrapment and escape of liquid lubricant in metal forming

    Bech, Jakob Ilsted; Bay, Niels; Eriksen, Morten


    Using a transparent tool entrapment, compression and eventual escape of liquid lubricant in surface pockets is observed in plane strip drawing. The two mechanisms of lubricant escape. Micro Plasto HydroDynamic and Hydrostatic Lubrication (MPHDL and MPHSL), are observed and quantified experimentally...


    Leszek Gardyński; Jolanta Kałdonek


    The paper presents the research results of lubricity of selected vegetable oils, rapeseed oil methyl esters, and esters with addition of oleic acid. Higher wear of samples during lubrication by rapeseed oil methyl esters in comparison to the tested vegetable oils was obtained. The addition of oleic acid to esters resulted in the improvement of their lubricating properties.

  19. Gravimetric Determination of Sediment in Turbine Engine Lubricating Oils.

    noncombustible sediment present in aircraft turbine engine lubricating oils . Both MIL-L-7808 and MIL-L-23699 lubricants were investigated. These...temperature. When these oils were heated to 140 F, they easily passed through a silver membrane filter. A test procedure for the gravimetric measurement of particulate contamination in turbine engine lubricating oils is proposed. (Author)


    Leszek Gardyński


    Full Text Available The paper presents the research results of lubricity of selected vegetable oils, rapeseed oil methyl esters, and esters with addition of oleic acid. Higher wear of samples during lubrication by rapeseed oil methyl esters in comparison to the tested vegetable oils was obtained. The addition of oleic acid to esters resulted in the improvement of their lubricating properties.

  1. FY2014 Fuel & Lubricant Technologies Annual Progress Report

    Stork, Kevin [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)


    Annual progress report for Fuel & Lubricant Technologies. The Fuel & Lubricant Technologies Program supports fuels and lubricants research and development (R&D) to provide vehicle manufacturers and users with cost-competitive options that enable high fuel economy with low emissions, and contribute to petroleum displacement.

  2. Micro-elastohydrodynamic lubrication in concentrated sliding contacts

    Sloetjes, Jan Willem


    Due to the trend of down-sizing, machine elements are forced to operate under increasingly severe conditions. For lubricated systems this means that the lubricating films reduce to a level such that asperity interaction starts to play a role. For this reason, the full film lubrication of concentrate

  3. Developments of New Lubricants for Cold Forging of Stainless Steel

    Steenberg, Thomas; Christensen, Erik; Olesen, P.


    Two new lubricant systems for cold forging of stainless steel have been developed. The main component of these systems are FeCl3 and ZnCa2(PO4)2, respectively. Both lubricant systems have been tested using a backward extrusion test. The results show excellent lubricating properties with respect...

  4. The history, genotoxicity, and carcinogenicity of carbon-based fuels and their emissions. Part 2: solid fuels.

    Claxton, Larry D


    The combustion of solid fuels (like wood, animal dung, and coal) usually involves elevated temperatures and altered pressures and genotoxicants (e.g., PAHs) are likely to form. These substances are carcinogenic in experimental animals, and epidemiological studies implicate these fuels (especially their emissions) as carcinogens in man. Globally, ∼50% of all households and ∼90% of all rural households use solid fuels for cooking or heating and these fuels often are burnt in simple stoves with very incomplete combustion. Exposed women and children often exhibit low birth weight, increased infant and perinatal mortality, head and neck cancer, and lung cancer although few studies have measured exposure directly. Today, households that cannot meet the expense of fuels like kerosene, liquefied petroleum gas, and electricity resort to collecting wood, agricultural residue, and animal dung to use as household fuels. In the more developed countries, solid fuels are often used for electric power generation providing more than half of the electricity generated in the United States. The world's coal reserves, which equal approximately one exagram, equal ∼1 trillion barrels of crude oil (comparable to all the world's known oil reserves) and could last for 600 years. Studies show that the PAHs that are identified in solid fuel emissions react with NO2 to form direct-acting mutagens. In summary, many of the measured genotoxicants found in both the indoor and electricity-generating combustors are the same; therefore, the severity of the health effects vary with exposure and with the health status of the exposed population. Copyright © 2014. Published by Elsevier B.V.

  5. Viscosity Measurement in a Lubricant Film Using an Ultrasonically Resonating Matching Layer

    Schirru, M.; Mills, R.; Dwyer-Joyce, R.; Smith, O; Sutton, M.


    A novel ultrasonic viscometer intended for in-situ applications in lubricated components is presented. The concept is based on the reflection of a shear wave at a solid-liquid boundary that depends on the viscosity of the liquid and the acoustic properties of the solid. Very little ultrasound energy can propagate into the oil at a metal-oil interface because the acoustic mismatch is great, and this leads to large measurement errors. The method described in this paper overcomes this limitation...

  6. Evaluation of two commercially-available lubricants by means of ring test to AA 6061 F aluminum alloys

    Rogério Alves Oliveira


    Full Text Available This paper shows friction results obtained through compression ring tests for two commercially-available lubricants (i.e., Oildag and Deltaforge applied in the hot forging of aluminum alloys. The experiments were performed with AA 6061 F aluminum alloy samples with the goal of observing the behavior of each lubricant in several conditions of temperature (200, 300, and 450 °C, strain rates (1, 10 and 50 s-1, and strain (25, 50 and 75%. The friction coefficients for each lubrication condition were established by means of calibration curves determined from finite element calculations with the use of the PEP/Larstran software package. An Analysis-of-Variance approach for the ring's internal diameter was followed in order to evaluate the performance of the lubricants. The results indicated that the Oildag lubricant presents a better stability as well as lower friction coefficients than the Deltaforge lubricant for the range of conditions tested, which translates into a better friction condition at die-part interface.

  7. Lubricants or lubricant additives composed of ionic liquids containing ammonium cations

    Qu, Jun [Knoxville, TN; Truhan, Jr; John, J [Cookeville, TN; Dai, Sheng [Knoxville, TN; Luo, Huimin [Knoxville, TN; Blau, Peter J [Knoxville, TN


    A lubricant or lubricant additive is an ionic liquid alkylammonium salt. The alkylammonium salt has the structure R.sub.xNH.sub.(4-x).sup.+,[F.sub.3C(CF.sub.2).sub.yS(O).sub.2].sub.2N.sup- .- where x is 1 to 3, R is independently C.sub.1 to C.sub.12 straight chain alkyl, branched chain alkyl, cycloalkyl, alkyl substituted cycloalkyl, cycloalkyl substituted alkyl, or, optionally, when x is greater than 1, two R groups comprise a cyclic structure including the nitrogen atom and 4 to 12 carbon atoms, and y is independently 0 to 11. The lubricant is effective for the lubrication of many surfaces including aluminum and ceramics surfaces.

  8. Development and evaluation of a high performance lubricant for industrial gears; Desenvolvimento e avaliacao de lubrificantes de alto desempenho para engrenagens industriais

    Araujo, Laura Denise Santiago de; Silva, Ademir Oliveira da [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Oliveira, Adelci Menezes de [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)


    Nowadays, new machines are submitted to higher efforts with smaller clearances. For them it is necessary to develop high performance lubricants in order to reduce friction, wear and emissions for internal combustion engines. In this work it was developed two lubricants, prepared with MoS{sub 2} (Molybdenum Disulfide) and LIC (Lubricant Intermetallic Compound), and they were compared to commercial oil, at the same viscosity grade ISO VG 320. The oils were tested in a four ball tribometer, at 1200 rpm, at initial temperature of 40 deg C and at 80 kgf. The friction reduction was of 13 % and 18 % for MoS{sub 2} and LIC oil, respectively. The wear was the same for all tested oils. Besides tests in the four ball machine, all oils were characterized by viscosity, demulsibility and atomic emission spectroscopy. The lubricants formulated with solids particles were considered as high performance. (author)

  9. Effect of load and speed on warship power rear drive system helical gear anti-scuffing properties in thermal elasto-hydrodynamic lubrication

    Yongmei Wang


    Full Text Available The key parameters which caused the scoring failure of helical gears are operating load and speed. In this study, the simulations using geometric meshing theory were carried out to investigate the effect of load and speed of warship transmission helical gear system on thermal elasto-hydrodynamic lubrication. The numerical algorithm for the analysis of three-dimensional thermal elasto-hydrodynamic lubrication used in this work has advantage that the film pressure and distributions can be calculated from Reynolds equation for all mixed lubrication regions without any specific boundary condition for the edge of solid contact region. Oil film pressure, film thickness as well as film temperature under different load and speed conditions were obtained and compared. In addition, experimental tests were conducted to determine gear surface temperature under different load and speed conditions. This work provided a guidance to understand the load- and speed-dependent thermal elasto-hydrodynamic lubrication.

  10. Thermal Elasto-Hydrodynamic Lubrication by Non - Fluids with Rough Surfaces: its Application to Spur Gear Transmission.

    Wang, Jian M.


    A theoretical investigation of the behavior of thermal elasto-hydrodynamic lubrication by non-Newtonian fluids under rough surfaces has been conducted. The study consists of two parts. In the first part, a general line contact elasto-hydrodynamic lubrication model is derived, which integrates several critical effects such as rheological characteristics of lubricants, roughness and temperature into one system. A more effective numerical algorithm is adopted to obtains the solutions under wide ranges of operating conditions. Observations and extensive discussions of the results lead to further understand the phenomena of the different interactions among the various factors in a elasto-hydrodynamic lubrication process. In the second part, the forgoing theory is applied to the specific problem of the spur gear transmission. Various kinematics and dynamics features associated with the lubrication process in the spur gear have been investigated. The results has shown that the pitch point EHL film thickness does not reliably represent the minimum EHL film thickness. The full thermal EHL calculation along the line of action is needed in order to predict the minimum film thickness and pressure peak more precisely. The actual location of the minimum film thickness along the line of action is strongly influenced by the dynamic load sharing profile. Surface roughness has the moderate effect on the gear lubrication. The effects become more significant when the roughness amplitudes approach the nominal film thickness. Non-Newtonian behavior of lubricants may significantly alter the level of the minimum film thickness and temperature distribution, but has only small effect on pressure peak.

  11. Toxicological characteristics of refinery streams used to manufacture lubricating oils.

    Kane, M L; Ladov, E N; Holdsworth, C E; Weaver, N K


    In the past, reports on the tumorigenic potential of lubricating oils in experimental animals have poorly defined the materials under study. In this paper the results of mouse skin painting studies with 46 clearly defined samples of refinery streams associated with lubricating oil processing show that modern conventional solvent refining of distillates removes tumorigenic potential while conventional acid refining may not. Furthermore, dewaxing, hydrofinishing, and clay treatments do not appear to mitigate the tumorigenicity of the lubricant distillates. Lubricant processing has changed over the years and assessments of the carcinogenicity of present-day lubricating materials must be based on knowledge of modern processing.

  12. Lubrication in Hot Tube Extrusion of Superalloys and Ti Alloys


    Tubular products made of superalloys and titanium alloys usually work in high temperature environment and applied heavy loading. Hot extrusion is the best technology to form tubular billets with fine microstructures and good mechanical properties. Lubrication is one of the key techniques in hot extrusion, glass lubricants are most suitable for hot extrusion. Lubrication technique in hot extrusion is dealt with in this paper, the lubrication principle of hot tube extrusion is presented. Experiments of glass lubricated backward tube extrusion of titanium alloys and forward tube extrusion of superalloys are also discussed.

  13. Mesure de la capacité différencielle de la double couche électrique en milieu hydrocarbure. Etude de l'interface métal-additifs pour lubrifiants. Première partie Measuring the Differential Capacity of the Electric Double Layer in a Hydrocarbon Medium. Analysis of the Metal Additive Interface for Lubricants. Part One

    Hipeaux J. C.


    Full Text Available Le phénomène d'adsorption d'additifs détergents-dispersants contenus dans les huiles lubrifiantes est à la base de l'action de ces produits. L'existence d'une double couche électrique est un des paramètres envisagés lors de l'étude de l'interface métal-milieu hydrocarbure. La structure de cette double couche en liaison avec le phénomène d'adsorption à l'interface (courbe électrocapillaire, énergie libre de surface, charge, capacité différentielle sont abordés. L'importance de la connaissance du potentiel de charge nulle est montrée. Une revue bibliographique des moyens d'accès à la mesure des capacités différentielles de la double couche est farte, l'objectif à atteindre étant le choix d'une technique de mesure possible en milieu hydrocarbure, sur électrode solide. Une méthode, basée sur l'étude du début de la charge de la double couche électrique et utilisant la superposition d'une tension carrée à une tension continue maintenue constante, est développée et l'étude théorique du circuit réalisée. Des courbes capacité différentielle = f (tension de polarisation sont tracées pour des solutions dans l'heptane de différents additifs utilisés en lubrification. Une réflexion sur les mécanismes d'adsorption est faite à partir de l'exploitation de ces courbes expérimentales. A titre de comparaison quelques tracés de courbes de capacité différentielle sont effectués avec un produit antistatique rendant fortement conducteur les hydrocarbures et un produit antiusure. Enfin un système de référence utilisant une électrode au calomel est proposé. The adsorption phenomena of detergent-dispersant additives contained in lubricating ails is behind for the action of such products. The existence of an electrical double layer is one of the parameters token into consideration when analyzing the métal/hydrocarbon medium interface. The structure of this double layer in connection with the adsorption phenomenon on

  14. Taxonomy of Means and Ends in Aquaculture Production—Part 2: The Technical Solutions of Controlling Solids, Dissolved Gasses and pH

    Bjorgvin Vilbergsson


    Full Text Available In engineering design, knowing the relationship between the means (technique and the end (desired function or outcome is essential. The means in Aquaculture are technical solutions like airlifts that are used to achive desired functionality (an end like controlling dissolved gasses. In previous work, the authors identified possible functions by viewing aquaculture production systems as transformation processes in which inputs are transformed by treatment techniques (means and produce outputs (ends. The current work creates an overview of technical solutions of treatment functions for both design and research purposes. A comprehensive literature review of all areas of technical solutions is identified and categorized into a visual taxonomy of the treatment functions for controlling solids, controlling dissolved gasses and controlling pH alkalinity and hardness. This article is the second in a sequence of four and partly presents the treatments functions in the taxonomy. The other articles in this series present complementary aspects of this research: Part 1, A transformational view on aquaculture and functions divided into input, treatment and output functions; Part 2, The current taxonomy paper; Part 3, The second part of the taxonomy; and Part 4, Mapping of the means (techniques for multiple treatment functions.

  15. Elastohydrodynamic Lubrication with Polyolester Lubricants and HFC Refrigerants, Final Report, Volume 1

    Gunsel, Selda; Pozebanchuk, Michael


    The objective of this study was to investigate the film formation properties of refrigeration lubricants using the ultrathin film elastohydrodynamic (EHD) interferometry technique and to study the effects of refrigerants on film formation. Film thickness measurements were conducted as a function of lubricant viscosity, speed, temperature, and refrigerant concentration. Based on the EHD film thickness data, effective pressure-viscosity coefficients were calculated for the test fluids at different temperatures and the effects of refrigerants on pressure-viscosity properties were investigated.

  16. Research Methods for Tribological Properties of Restorative and Preventive Coatings in Different Lubricating Media at Sliding Friction

    Nikolov Mitko


    Full Text Available A large part of machines (85–90 % (Garkunov, 2003 lose their efciency due to wear of parts, which disrupts their normal interaction, causes additional loading, shocks and vibrations, leads to seizures and jams and to accidents in many cases. This paper presents research methods for tribological properties of restorative and preventive coatings in diferent lubricating media at sliding friction.

  17. Operator models for delivering municipal solid waste management services in developing countries. Part A: The evidence base.

    Wilson, David C; Kanjogera, Jennifer Bangirana; Soós, Reka; Briciu, Cosmin; Smith, Stephen R; Whiteman, Andrew D; Spies, Sandra; Oelz, Barbara


    This article presents the evidence base for 'operator models' - that is, how to deliver a sustainable service through the interaction of the 'client', 'revenue collector' and 'operator' functions - for municipal solid waste management in emerging and developing countries. The companion article addresses a selection of locally appropriate operator models. The evidence shows that no 'standard' operator model is effective in all developing countries and circumstances. Each city uses a mix of different operator models; 134 cases showed on average 2.5 models per city, each applying to different elements of municipal solid waste management - that is, street sweeping, primary collection, secondary collection, transfer, recycling, resource recovery and disposal or a combination. Operator models were analysed in detail for 28 case studies; the article summarises evidence across all elements and in more detail for waste collection. Operators fall into three main groups: The public sector, formal private sector, and micro-service providers including micro-, community-based and informal enterprises. Micro-service providers emerge as a common group; they are effective in expanding primary collection service coverage into poor- or peri-urban neighbourhoods and in delivering recycling. Both public and private sector operators can deliver effective services in the appropriate situation; what matters more is a strong client organisation responsible for municipal solid waste management within the municipality, with stable political and financial backing and capacity to manage service delivery. Revenue collection is also integral to operator models: Generally the municipality pays the operator from direct charges and/or indirect taxes, rather than the operator collecting fees directly from the service user.

  18. Usefulness of texture analysis in differentiating transient from persistent part-solid nodules(PSNs: a retrospective study.

    Sang Hwan Lee

    Full Text Available BACKGROUND: Early discrimination between transient and persistent par-solid ground-glass nodules (PSNs at CT is essential for patient management. The objective of our study was to retrospectively investigate the value of texture analysis in differentiating pulmonary transient and persistent PSNs in addition to clinical and CT features. METHODS: This retrospective study was performed with IRB approval and a waiver of the requirement for patients' informed consent. From January 2007 to October 2009, we identified 77 individuals (39 men and 38 women; mean age, 55 years with 86 PSNs on thin-section chest CT. Thirty-nine PSNs in 31 individuals were transient and 47 PSNs in 46 patients were persistent. The clinical, CT, and texture features of PSNs were evaluated. To investigate the additional value of texture analysis in differentiating transient from persistent PSNs, logistic regression analysis and C-statistics were performed. RESULTS: Between transient and persistent PSNs, there were significant differences in age, gender, smoking history, and eosinophil count among the clinical features. As for thin-section CT features, there were significant differences in lesion size, solid portion size, and lesion multiplicity. In terms of texture features, there were significant differences in mean attenuation, skewness of whole PSN, attenuation ratio of whole PSN to inner solid portion, and 5-, 10-, 25-, 50-percentile CT numbers of whole PSN. Multivariate analysis revealed eosinophilia, lesion size, lesion multiplicity, mean attenuation of whole PSN, skewness of whole PSN, and 5-percentile CT number were significant independent predictors of transient PSNs. (P<0.05 C-statistics revealed that texture analysis incorporating clinical and CT features (AUC, 92.9% showed significantly higher differentiating performance of transient from persistent PSNs compared with the clinical and CT features alone (AUC, 79.0%. (P =  0.004. CONCLUSION: Texture analysis of

  19. Distributed mixed-integer fuzzy hierarchical programming for municipal solid waste management. Part II: scheme analysis and mechanism revelation.

    Cheng, Guanhui; Huang, Guohe; Dong, Cong; Xu, Ye; Chen, Jiapei; Chen, Xiujuan; Li, Kailong


    As presented in the first companion paper, distributed mixed-integer fuzzy hierarchical programming (DMIFHP) was developed for municipal solid waste management (MSWM) under complexities of heterogeneities, hierarchy, discreteness, and interactions. Beijing was selected as a representative case. This paper focuses on presenting the obtained schemes and the revealed mechanisms of the Beijing MSWM system. The optimal MSWM schemes for Beijing under various solid waste treatment policies and their differences are deliberated. The impacts of facility expansion, hierarchy, and spatial heterogeneities and potential extensions of DMIFHP are also discussed. A few of findings are revealed from the results and a series of comparisons and analyses. For instance, DMIFHP is capable of robustly reflecting these complexities in MSWM systems, especially for Beijing. The optimal MSWM schemes are of fragmented patterns due to the dominant role of the proximity principle in allocating solid waste treatment resources, and they are closely related to regulated ratios of landfilling, incineration, and composting. Communities without significant differences among distances to different types of treatment facilities are more sensitive to these ratios than others. The complexities of hierarchy and heterogeneities pose significant impacts on MSWM practices. Spatial dislocation of MSW generation rates and facility capacities caused by unreasonable planning in the past may result in insufficient utilization of treatment capacities under substantial influences of transportation costs. The problems of unreasonable MSWM planning, e.g., severe imbalance among different technologies and complete vacancy of ten facilities, should be gained deliberation of the public and the municipal or local governments in Beijing. These findings are helpful for gaining insights into MSWM systems under these complexities, mitigating key challenges in the planning of these systems, improving the related management

  20. A strategy for Earth science from space in the 1980s. Part 1: Solid earth and oceans


    The report develops a ten-year science strategy for investigating the solid earth and dynamics of world oceans from Earth orbit. The strategy begins from the premise that earth studies have proceeded to the point where further advances in understanding Earth processes must be based on a global perspective and that the U.S. is technically ready to begin a global study approach from Earth orbit. The major areas of study and their fundamental problems are identified. The strategy defines the primary science objectives to be addressed and the essential measurements and precision to achieve them.

  1. Physicochemical characterization of Au/CeO{sub 2} solid. Part 1: The deposition-precipitation preparation method

    Aboukaies, Antoine, E-mail: [Univ Lille Nord de France, 59000 Lille (France); Equipe Catalyse, UCEIV, E.A. 4492, MREI, ULCO, 59140 Dunkerque (France); Aouad, Samer [Univ Lille Nord de France, 59000 Lille (France); Equipe Catalyse, UCEIV, E.A. 4492, MREI, ULCO, 59140 Dunkerque (France); Department of Chemistry, University of Balamand, P.O. Box 100, Tripoli (Lebanon); El-Ayadi, Houda [Univ Lille Nord de France, 59000 Lille (France); Equipe Catalyse, UCEIV, E.A. 4492, MREI, ULCO, 59140 Dunkerque (France); Skaf, Mira [Univ Lille Nord de France, 59000 Lille (France); Equipe Catalyse, UCEIV, E.A. 4492, MREI, ULCO, 59140 Dunkerque (France); Department of Chemistry, University of Balamand, P.O. Box 100, Tripoli (Lebanon); Labaki, Madona; Cousin, Renaud; Abi-Aad, Edmond [Univ Lille Nord de France, 59000 Lille (France); Equipe Catalyse, UCEIV, E.A. 4492, MREI, ULCO, 59140 Dunkerque (France)


    Au/CeO{sub 2} (4 wt.% gold) solid was prepared using the deposition-precipitation method. The deposition of gold on ceria did not affect its specific surface area (122 m{sup 2} g{sup -1}/400 Degree-Sign C). The average diameter of gold particles obtained was estimated to be equal to 3.9 nm. Moreover, 60% of the gold was in the form of nanoparticles with a size ranging between 3 and 4 nm. 80% of the gold in the nanoparticles was in the metallic form Au{sup 0} and 20% was present as Au{sup +}. These latter cations interact directly with the O{sup 2-} anions of CeO{sub 2}. When evacuated at 400 Degree-Sign C for 1 h, the cations were reduced into Au{sup 0}. All the adsorptions were performed on solids treated under vacuum at 400 Degree-Sign C for 1 h. The adsorption of O{sub 2} at room temperature led to the formation of O{sub 2}{sup -} species. The adsorption of {sup 17}O-enriched molecular oxygen demonstrated that the two oxygen atoms in O{sub 2}{sup -} are equivalent. When CO was introduced, it reacted with the O{sub 2}{sup -} of the support to give CO{sub 2}{sup -}. When NO{sub 2}, NO or N{sub 2}O were added at room temperature, they decomposed to form adsorbed O{sub 2}{sup -} species at the surface of the solid. -- Highlights: Black-Right-Pointing-Pointer Au/CeO{sub 2} solid prepared by the deposition-precipitation method presents highly dispersed Au nanoparticles. Black-Right-Pointing-Pointer The adsorption on Au/CeO{sub 2} of NO, NO{sub 2}, N{sub 2}O and O{sub 2} leads to the formation of O{sub 2}{sup -}. Black-Right-Pointing-Pointer The adsorption of CO on Au/CeO{sub 2} leads to the formation of CO{sub 2}{sup -}. Black-Right-Pointing-Pointer The adsorption of {sup 17}O{sub 2} on Au/CeO{sub 2} shows that the two adsorbed oxygen are equivalent.

  2. A quantitative lubricant test for deep drawing

    Olsson, David Dam; Bay, Niels; Andreasen, Jan L.


    A tribological test for deep drawing has been developed by which the performance of lubricants may be evaluated quantitatively measuring the maximum backstroke force on the punch owing to friction between tool and workpiece surface. The forming force is found not to give useful information...

  3. Auto Mechanics: Auto Mechanic Service Specialist (Lubrication).

    Hoover, Virgil

    The unit of individualized learning activities is designed to provide training in the job skill, lubrication, for the prospective auto mechanic service specialist. The materials in the unit are divided into two sections. The developmental, or preliminary phase, for use by the instructor, includes brief descriptions of the job and of the student…

  4. Lubrication modes and the IRG transition diagram

    Schipper, D.J.; Gee, de A.W.J.


    The relationship between a Lubrication Mode Diagram (LMD) for concentrated contacts (LCC's) and the IRG transition diagram has been studied. In addition, scuffing results, obtained by the IRG (International Research Group) have been analysed, as well as the results of scuffing tests performed by dif

  5. Mechanism of lubrication by tricresylphosphate (TCP)

    Faut, O. D.; Buckley, D. H.


    The coefficient of friction was measured as a function of temperature on a pin-on-disk tribometer. Pins and disks of 440C and 52100 steels were lubricated with tricresylphosphate (TCP), 3.45 percent TCP in squalene, and pure squalene. The M-50 pins and disks were lubricated with 3.45 percent TCP in squalene and pure squalene. Experiments were conducted under limited lubrication conditions in dry ( 100 ppm H2O) air and dry ( pp H2O) nitrogen at 50 rpm (equivalent to a sliding velocity of 13 cm sec) and a constant load of 9.8 N (1 kg). Characteristic temperatures T sub r were identified for TCP on 52100 steel and for squalene on M-50 and 52100 steels, where the friction decreased because of a chemical reaction between the lubricant and the metal surface. The behavior of squalene obscured the influence of 3.45 percent TCP solute on the friction of the system. Wear volume measurements demonstrated that wear was lowest at temperatures just above T sub r. Comparing the behavior of TCP on M-50, 440C, and 52100 steels revealed that the TCP either reacted to give T sub r behavior or produced initial failure in the temperature range 223 + or - 5 C.

  6. Current Trends in Biobased Lubricant Development

    Biobased lubricants are those comprising ingredients derived from natural raw materials such as those harvested from farms, forests, etc. Biolubricants provide a number of benefits over petroleum-based products including: biodegradability, renewability, and non-toxicity. As a result, manufacture ...

  7. Biobased Lubricant Development - Problems and Opportunities

    Biobased lubricants are those comprising ingredients derived from natural sources such as those harvested from farms, forests, etc. Biolubricants provide a number of economic, environmental and health benefits over petroleum-based products. Among these are: biodegradability, renewability and non-t...

  8. Lubricant Test Methods for Sheet Metal Forming

    Bay, Niels; Olsson, David Dam; Andreasen, Jan Lasson


    Sheet metal forming of tribologically difficult materials such as stainless steel, Al-alloys and Ti-alloys or forming in tribologically difficult operations like ironing, punching or deep drawing of thick plate requires often use of environmentally hazardous lubricants such as chlorinated paraffin...

  9. New crop oils - Properties as potential lubricants

    New crops oils such as lesquerella, field pennycress, meadowfoam and cuphea were investigated and compared to common commodity vegetable oils for their fatty acid profiles, low temperature and lubricating properties. The fatty acid profile investigation showed that lesquerella is high in hydroxy fat...

  10. Classification of lubricants according to cavitation criteria

    Meged, Y.; Venner, C.H.; Napel, ten W.E


    Cavitation in lubrication liquids has long been known to be detrimental to components in hydraulic systems. Damage has been detected in journal bearings, especially under severe dynamic loading, gears, squeeze film dampers and valves. These findings have led to intensive studies of metal resistance

  11. Fuels and Lubricants. Selecting and Storing.

    Parady, W. Harold; Colvin, Thomas S.

    The manual presents basic information for the person who plans to operate or service tractors, trucks, industrial engines, and automobiles. It tells how to select the proper fuels and lubricants and how to store them properly. Although there are no prerequisites to the study of the text, a general knowledge of engines and mobile-type vehicles is…

  12. 40 CFR 1065.740 - Lubricants.


    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Lubricants. 1065.740 Section 1065.740 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Engine Fluids, Test Fuels, Analytical Gases and Other Calibration Standards § 1065.740...

  13. Modern advancements in lubricating grease technology

    Lugt, Pieter Martin


    Grease is one of the major bearing components and the performance of a grease lubricated bearing is strongly determined by the performance of the grease. This paper describes how grease knowledge is linked to improved rolling bearing performance. First the various performance indicators will be desc


    Wojciech HORAK


    Full Text Available The paper presents the results of research about alternative grease - glycerin. Tests were made on four-ball apparatus. Analysis of results confirms that glycerin can be used for lubrication in friction nodes. This work includes results of wear tests in case of using a few glycerin water solutions with different concentration and comparison with typical greases.

  15. Water lubricates hydrogen-bonded molecular machines

    Panman, M.R.; Bakker, B.H.; den Uyl, D.; Kay, E.R.; Leigh, D.A.; Buma, W.J.; Brouwer, A.M.; Geenevasen, J.A.J.; Woutersen, S.


    The mechanical behaviour of molecular machines differs greatly from that of their macroscopic counterparts. This applies particularly when considering concepts such as friction and lubrication, which are key to optimizing the operation of macroscopic machinery. Here, using time-resolved vibrational

  16. On the lubrication of mechanical face seals

    Lubbinge, Hans


    Hence, in this thesis, a model is presented which is able to calculate a complete Stribeck curve for a mechanical face seal and, as a consequence, the transition from full film to mixed lubrication as a function of the operational conditions. This model is based on a combination of a contact model a

  17. Tribology: Friction, lubrication, and wear technology

    Blau, Peter J.


    The topics are presented in viewgraph form and include the following: introduction and definitions of terms; friction concepts; lubrication technology concepts; wear technology concepts; and tribological transitions. This document is designed for educators who seek to teach these concepts to their students.

  18. Exploring Low Emission Lubricants for Diesel Engines

    Perez, J. M.


    A workshop to explore the technological issues involved with the removal of sulfur from lubricants and the development of low emission diesel engine oils was held in Scottsdale, Arizona, January 30 through February 1, 2000. It presented an overview of the current technology by means of panel discussions and technical presentations from industry, government, and academia.

  19. Study on Lubricating Oil Monitoring Technology

    LIU Feng-bi


    Lubricating oil monitoring has been proven to be an effective method for detecting and diagnosing machinery failures and essential for realizing condition based maintenance. In this paper, mathematical statistics methods for determining the oil parameters featuring machinery failures and the parameters' probability distribution functions and their thresholds are put forward.

  20. Lubricant degradation and related wear of a steel pin in lubricated sliding against a steel disc.

    Singh, Archana; Gandra, Ravi T; Schneider, Eric W; Biswas, Sanjay K


    In lubricated sliding contacts, components wear out and the lubricating oil ages with time. The present work explores the interactive influence between lubricant aging and component wear. The flat face of a steel pin is slid against a rotating steel disk under near isothermal conditions while the contact is immersed in a reservoir of lubricant (hexadecane). The chemical changes in the oil with time are measured by vibrational spectroscopy and gas chromatography. The corresponding chemistry of the pin surface is recorded using X-ray photoelectron spectroscopy while the morphology of the worn pins; surface and subsurface, are observed using a combination of focused ion beam milling and scanning electron microscopy. When compared to thermal auto-oxidation of the lubricant alone, steel on steel friction and wear are found to accentuate the decomposition of oil and to reduce the beneficial impact of antioxidants. The catalytic action of nascent iron, an outcome of pin wear and disk wear, is shown to contribute to this detrimental effect. Over long periods of sliding, the decomposition products of lubricant aging on their own, as well as in conjunction with their products of reaction with iron, generate a thick tribofilm that is highly protective in terms of friction and wear.

  1. Systems Analysis of Technologies for Energy Recovery from Waste. Part I. Gasification followed by Catalytic Combustion, PEM Fuel Cells and Solid Oxide Fuel Cells for Stationary Applications in Comparison with Incineration. Part - II. Catalytic combustion - Experimental part

    Assefa, Getachew; Frostell, Bjoern [Royal Inst. of Technology, Stockholm (Sweden). Div. of Industrial Ecology; Jaeraas, Sven; Kusar, Henrik [Royal Inst. of Technology, Stockholm (Sweden). Div. of Chemical Technology


    This project is entitled 'Systems Analysis: Energy Recovery from waste, catalytic combustion in comparison with fuel cells and incineration'. Some of the technologies that are currently developed by researchers at the Royal Institute of Technology include catalytic combustion and fuel cells as downstream units in a gasification system. The aim of this project is to assess the energy turnover as well as the potential environmental impacts of biomass/waste-to-energy technologies. In second part of this project economic analyses of the technologies in general and catalytic combustion and fuel cell technologies in particular will be carried out. Four technology scenarios are studied: (1) Gasification followed by Low temperature fuel cells (Proton Exchange Membrane (PEM) fuel cells) (2) Gasification followed by high temperature fuel cells (Solid Oxide Fuel Cells (SOFC) (3) Gasification followed by catalytic combustion and (4) Incineration with energy recovery. The waste used as feedstock is an industrial waste containing parts of household waste, paper waste, wood residues and poly ethene. In the study compensatory district heating is produced by combustion of biofuel. The power used for running the processes in the scenarios will be supplied by the waste-to-energy technologies themselves while compensatory power is assumed to be produced from natural gas. The emissions from the system studied are classified and characterised using methodology from Life Cycle Assessment in to the following environmental impact categories: Global Warming Potential, Acidification Potential, Eutrophication Potential and finally Formation of Photochemical Oxidants. Looking at the result of the four technology chains in terms of the four impact categories with impact per GWh electricity produced as a unit of comparison and from the perspective of the rank each scenario has in all the four impact categories, SOFC appears to be the winner technology followed by PEM and CC as second


    Gao Chuangkuan; Qi Xiumei; Xiong Shibo


    Based on a lot of numerical solutions to the problems of the thermal non-Newtonian elastohydrodynamic lubrication and some fatigue tests with rollers, the lubrication factor of involute spur gears (called gear for short) is investigated. The results suggest that gear lubrication effects bear close relations to a dimensionless parameter D which is synthetically determined by gearing rotational speed, load, material, dimension and lubricant viscosity. When D≤8, the gear fatigue life increases as the lubricant viscosity is increased; When D>8, however, the life decreases with the viscosity addition, which is in marked contrast to the lubrication factor ZL recommended by the International Standard for Computing Cylindrical Gear Strength. At the end, a set of formulae for calculating gear lubrication factors suitable for different working conditions are advanced.

  3. Schemes for applying active lubrication to main engine bearings

    Estupinan, Edgar Alberto; Santos, Ilmar


    and consequently reducing viscous friction losses and vibrations. One refers to active lubrication when conventional hydrodynamic lubrication is combined with dynamically modified hydrostatic lubrication. In this case, the hydrostatic lubrication is modified by injecting oil at controllable pressures, through......The work presented here is a theoretical study that describes two different schemes for the oil injection system in actively lubricated main engine bearings. The use of active lubrication in journal bearings helps to enhance the hydrodynamic fluid film by increasing the fluid film thickness...... orifices circumferentially located around the bearing surface. The pressure distribution of the hydrodynamic fluid film in journal bearings is governed by the Reynolds equation, which is modified to accommodate the dynamics of active lubrication, and which can be numerically solved using finite...

  4. Municipal solid wastes management. cost evaluation of selective collecting; Gestion integral de residuos urbanos. Evaluacion de rendimientos y costes de la recogida selectiva (Parte I)

    Baldasano, J. M.; Ginestar, X.; Perez, C.; Gasso, S.


    The Spanish Nuclear Plan for Municipal Solid Waste (PNRU 2000-2006) includes and integrated waste management model that arranges the management options of waste in order of priority: minimization, re-use, recycling (including composting and biomethanisation), energy recovery and final disposal. This paper makes an evaluation of the cost increase of the MSW separate collection for recycling compared to the traditional collection system. This first part includes a description of the different possibilities to carry out the separate collection in terms of materials (containers and collectors), human resources and performances, as well as a comparison between its unitary costs. (Author)

  5. Assessment of lubricating oil degradation in small motorcycle engine fueled with gasohol

    Nakorn Tippayawong


    Assessment of the degradation of lubricating oil was performed on the lubricants which had been used in a small motorcycle engine fueled with gasohol in comparison with the lubricants from gasoline-run engine. The lubricant properties examined in the assessment were lubricating capacity, viscosity and stability to oxidation. Lubricating capacity was evaluated by accelerated wear test on the Timken tester. Lubricating oils from gasohol-run engine appeared to produce about 10% greater wear than...

  6. Distributed mixed-integer fuzzy hierarchical programming for municipal solid waste management. Part I: System identification and methodology development.

    Cheng, Guanhui; Huang, Guohe; Dong, Cong; Xu, Ye; Chen, Xiujuan; Chen, Jiapei


    Due to the existence of complexities of heterogeneities, hierarchy, discreteness, and interactions in municipal solid waste management (MSWM) systems such as Beijing, China, a series of socio-economic and eco-environmental problems may emerge or worsen and result in irredeemable damages in the following decades. Meanwhile, existing studies, especially ones focusing on MSWM in Beijing, could hardly reflect these complexities in system simulations and provide reliable decision support for management practices. Thus, a framework of distributed mixed-integer fuzzy hierarchical programming (DMIFHP) is developed in this study for MSWM under these complexities. Beijing is selected as a representative case. The Beijing MSWM system is comprehensively analyzed in many aspects such as socio-economic conditions, natural conditions, spatial heterogeneities, treatment facilities, and system complexities, building a solid foundation for system simulation and optimization. Correspondingly, the MSWM system in Beijing is discretized as 235 grids to reflect spatial heterogeneity. A DMIFHP model which is a nonlinear programming problem is constructed to parameterize the Beijing MSWM system. To enable scientific solving of it, a solution algorithm is proposed based on coupling of fuzzy programming and mixed-integer linear programming. Innovations and advantages of the DMIFHP framework are discussed. The optimal MSWM schemes and mechanism revelations will be discussed in another companion paper due to length limitation.

  7. Lubrication performance and mechanisms of Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxide nanoparticles as lubricant additives

    Li, Shuo [School of Materials Science and Technology, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian Distract, Beijing 100083 (China); Nanoprobe Laboratory for Bio- & Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue Columbus, OH 43210-1142 (United States); Bhushan, Bharat, E-mail: [Nanoprobe Laboratory for Bio- & Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue Columbus, OH 43210-1142 (United States)


    Highlights: • Mg/Al-, Zn/Al- and Zn/Mg/Al-layered double hydroxide were synthesized. • Mg/Al-LDH had superior tribological performance compared to other LDHs. • The best thermal stability of Mg/Al-LDH was responsible for its friction property. - Abstract: Solid lubricant particles are commonly used as oil additives for low friction and wear. Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxides (LDH) were synthesized by coprecipitation method. The benefits of LDH nanoparticles are that they can be synthesized using chemical methods where size and shape can be controlled, and can be modified organically to allow dispersal in fluids. The LDH nanoparticles were characterized by X-ray diffraction, scanning electron microscope, thermogravimetry, and differential scanning calorimetry. A pin-on-disk friction and wear tester was used for evaluating the friction and wear properties of LDH nanoparticles as lubricant additives. LDH nanoparticles have friction-reducing and anti-wear properties compared to oil without LDHs. Mg/Al-LDH has the best lubrication, possibly due to better thermal stability in severe conditions.

  8. Lubricant-impregnated surfaces for drag reduction in viscous laminar flow

    Solomon, Brian; Khalil, Karim; Varanasi, Kripa; MIT Team


    For the first time, we explore the potential of lubricant impregnated surfaces (LIS) in reducing drag. LIS, inspired by the surface of the Nepenthes pitcher plant, have been introduced as a novel way of functionalizing a surface. LIS are characterized by extremely low contact angle hysteresis and have been show to effectively repel various liquids including water, oils, ketchup and blood. Motivated by the slippery nature of such surfaces, we explore the potential of LIS to reduce drag in internal flows. We observe a reduction in drag for LIS surfaces in a viscous laminar drag flow and model the impact of relevant system parameters (lubricant viscosity, working fluid viscosity, solid fraction, depth of texture, etc.).

  9. Thermochemical recycling of mixture of scrap tyres and waste lubricating oil into high caloric value products

    Abdul-Raouf, Manar E.; Maysour, Nermine E.; Abdul-Azim, Abdul-Azim A. [Egyptian Petroleum Research Institute, Nasr City, Cairo (Egypt); Amin, Mahasen S. [Faculty of Science, Benha University, Benha (Egypt)


    Scrap tyres and used lubricating oils represent together growing environmental problem because they are not biodegradable and their components cannot readily be recovered. In the present investigation, the thermochemical recycling of mixture of old tyres with waste lubricating oil by pyrolysis and the value of the products obtained have been studied. First, thermobalance experiments were carried out, studying the influence of the following variables: temperature, type of catalyst and catalyst concentration on the pyrolysis reaction of a mixture of 1/1 wt./wt. oil/tyre ratio. These thermobalance results were thoroughly investigated to study the effect of the main process variables on yields of derived products: oils, gases and solid residue. (author)

  10. Nanoscale Lubrication of Ionic Surfaces Controlled via a Strong Electric Field

    Strelcov, Evgheni; Kumar, Rajeev; Bocharova, Vera; Sumpter, Bobby G.; Tselev, Alexander; Kalinin, Sergei V.


    Frictional forces arise whenever objects around us are set in motion. Controlling them in a rational manner means gaining leverage over mechanical energy losses and wear. This paper presents a way of manipulating nanoscale friction by means of in situ lubrication and interfacial electrochemistry. Water lubricant is directionally condensed from the vapor phase at a moving metal-ionic crystal interface by a strong confined electric field, thereby allowing friction to be tuned up or down via an applied bias. The electric potential polarity and ionic solid solubility are shown to strongly influence friction between the atomic force microscope (AFM) tip and salt surface. An increase in friction is associated with the AFM tip digging into the surface, whereas reducing friction does not influence its topography. No current flows during friction variation, which excludes Joule heating and associated electrical energy losses. The demonstrated novel effect can be of significant technological importance for controlling friction in nano- and micro-electromechanical systems.

  11. Single Common Powertrain Lubricant (SCPL) Development. Part 3


    results for: chemical and physical bench testing, transmission application frictional testing, high temperature 2-cycle diesel engine compatibility...industry standardized testing. However, all testing in military applications (apart from high temperature two cycle diesel engines ) has shown positive...application frictional testing, high temperature 2-cycle diesel engine compatibility, and Mack T-12 wear performance testing. All testing shows that

  12. Part 2 -- current program integrating strategies and lubrication technology

    Johnson, B.


    This paper is the second of two that describe the Predictive Maintenance Program for rotating machinery at the Palo Verde Nuclear Generating Station. The Predictive Maintenance program has been enhanced through organizational changes and improved interdisciplinary usage of technology. This paper will discuss current program strategies that have improved the interaction between the Vibration and Lube Oil programs. The {open_quotes}Lube Oil{close_quotes} view of the combined program along with case studies will then be presented.


    V. A. Okovity


    Full Text Available The paper presents an oxide ceramic material with addition of solid lubricant which has good technological characteristics and which is able to form high wear-resistant plasma coatings with low friction coefficient.

  14. The effect of lubricant constituents on lubrication mechanisms in hip joint replacements.

    Nečas, David; Vrbka, Martin; Urban, Filip; Křupka, Ivan; Hartl, Martin


    The aim of the present paper is to provide a novel experimental approach enabling to assess the thickness of lubricant film within hip prostheses in meaning of the contribution of particular proteins. Thin film colorimetric interferometry was combined with fluorescent microscopy finding that a combination of optical methods can help to better understand the interfacial lubrication processes in hip replacements. The contact of metal femoral head against a glass disc was investigated under various operating conditions. As a test lubricant, the saline solution containing the albumin and γ-globulin in a concentration 2:1 was employed. Two different mean speeds were applied, 5.7 and 22mm/s, respectively. The measurements were carried out under pure rolling, partial negative and partial positive sliding conditions showing that kinematic conditions substantially affects the formation of protein film. Under pure rolling conditions, an increasing tendency of lubricant film independently on rolling speed was detected, while the total thickness of lubricant film can be attributed mainly to albumin. When the ball was faster than the disc (negative sliding), a very thin lubricant film was observed for lower speed with no significant effect of particular proteins. The increase in sliding speed led to the increase of film thickness mainly caused due to the presence of γ-globulin. On the contrary, when the disc was faster than the ball (positive sliding), the film formation was very complex and time dependent while both of the studied proteins have shown any qualitative change during the test, however the effect of albumin seems to be much more important. Since a very good agreement of the results was obtained, it can be concluded that the approach consisting of two optical methods can provide the fundamental information about the lubricant film formation in meaning of particular proteins while the simultaneous presence of other constituents in model synovial fluid.

  15. Boundary mode lubrication of articular cartilage by recombinant human lubricin.

    Gleghorn, Jason P; Jones, Aled R C; Flannery, Carl R; Bonassar, Lawrence J


    Lubrication of cartilage involves a variety of physical and chemical factors, including lubricin, a synovial glycoprotein that has been shown to be a boundary lubricant. It is unclear how lubricin boundary lubricates a wide range of bearings from tissue to artificial surfaces, and if the mechanism is the same for both soluble and bound lubricin. In the current study, experiments were conducted to investigate the hypothesis that recombinant human lubricin (rh-lubricin) lubricates cartilage in a dose-dependent manner and that soluble and bound fractions of rh-lubricin both contribute to the lubrication process. An rh-lubricin dose response was observed with maximal lubrication achieved at concentrations of rh-lubricin greater than 50 microg/mL. A concentration-response variable-slope model was fit to the data, and indicated that rh-lubricin binding to cartilage was not first order. The pattern of decrease in equilibrium friction coefficient indicated that aggregation of rh-lubricin or steric arrangement may regulate boundary lubrication. rh-lubricin localized at the cartilage surface was found to lubricate a cartilage-glass interface in boundary mode, as did soluble rh-lubricin at high concentrations (150 microg/mL); however, the most effective lubrication occurred when both soluble and bound rh-lubricin were present at the interface. These findings point to two distinct mechanisms by which rh-lubricin lubricates, one mechanism involving lubricin bound to the tissue surface and the other involving lubricin in solution.

  16. Water Lubrication of Stainless Steel using Reduced Graphene Oxide Coating

    Kim, Hae-Jin; Kim, Dae-Eun


    Lubrication of mechanical systems using water instead of conventional oil lubricants is extremely attractive from the view of resource conservation and environmental protection. However, insufficient film thickness of water due to low viscosity and chemical reaction of water with metallic materials have been a great obstacle in utilization of water as an effective lubricant. Herein, the friction between a 440 C stainless steel (SS) ball and a 440 C stainless steel (SS) plate in water lubrication could be reduced by as much as 6-times by coating the ball with reduced graphene oxide (rGO). The friction coefficient with rGO coated ball in water lubrication was comparable to the value obtained with the uncoated ball in oil lubrication. Moreover, the wear rate of the SS plate slid against the rGO coated ball in water lubrication was 3-times lower than that of the SS plate slid against the uncoated ball in oil lubrication. These results clearly demonstrated that water can be effectively utilized as a lubricant instead of oil to lower the friction and wear of SS components by coating one side with rGO. Implementation of this technology in mechanical systems is expected to aid in significant reduction of environmental pollution caused by the extensive use of oil lubricants.

  17. MEMS Lubrication by In-Situ Tribochemical Reactions From the Vapor Phase.

    Dugger, Michael Thomas; Asay, David B.; Kim, Seong H.


    Vapor Phase Lubrication (VPL) of silicon surfaces with pentanol has been demonstrated. Two potential show stoppers with respect to application of this approach to real MEMS devices have been investigated. Water vapor was found to reduce the effectiveness of VPL with alcohol for a given alcohol concentration, but the basic reaction mechanism observed in water-free environments is still active, and devices operated much longer in mixed alcohol and water vapor environments than with chemisorbed monolayer lubricants alone. Complex MEMS gear trains were successfully lubricated with alcohol vapors, resulting in a factor of 104 improvement in operating life without failure. Complex devices could be made to fail if operated at much higher frequencies than previously used, and there is some evidence that the observed failure is due to accumulation of reaction products at deeply buried interfaces. However, if hypothetical reaction mechanisms involving heated surfaces are valid, then the failures observed at high frequency may not be relevant to operation at normal frequencies. Therefore, this work demonstrates that VPL is a viable approach for complex MEMS devices in conventional packages. Further study of the VPL reaction mechanisms are recommended so that the vapor composition may be optimized for low friction and for different substrate materials with potential application to conventionally fabricated, metal alloy parts in weapons systems. Reaction kinetics should be studied to define effective lubrication regimes as a function of the partial pressure of the vapor phase constituent, interfacial shear rate, substrate composition, and temperature.

  18. Diode laser pumped solid state laser. Part IV. ; Noise analysis. Handotai laser reiki kotai laser. 4. ; Noise kaiseki

    Sakurai, H.; Seno, T.; Tanabe, Y. (Asahi Glass Co. Ltd., Tokyo (Japan))


    Concerning the second harmonic generation(SHG) of diode laser pumped solid state laser using a nonlinear optical material, the researches are carried out to pracitically apply to the optical pickup. Therefore, the reduction of output optical noise has become the important researching subject. The theoretical and experimental analyses of noise generating mechanism were carried out for the system in which Nd;YAG as the laser diode and KTP (KTiOPO {sub 4}) as the nonlinear optical crystal were used. The following findings for the noise generating mechanism could be obtained: The competitive interaction between the polarization modes was dominant noise mechanism in the high frequency range from 1 to 20MHz and the noise could be removed sufficiently by using the QWP(quarter wave plate). On the other hand, the noise observed in the low frequency range from 100 to 200kHz depended on the resonance length, agreed qualitatively with the theoretical analysis of the noise to the competitive longitudinal modes and agreed quantitatively with the noise generating frequency range. 10 refs., 13 figs., 1 tab.

  19. Review of LCA studies of solid waste management systems--part II: methodological guidance for a better practice.

    Laurent, Alexis; Clavreul, Julie; Bernstad, Anna; Bakas, Ioannis; Niero, Monia; Gentil, Emmanuel; Christensen, Thomas H; Hauschild, Michael Z


    Life cycle assessment (LCA) is increasingly used in waste management to identify strategies that prevent or minimise negative impacts on ecosystems, human health or natural resources. However, the quality of the provided support to decision- and policy-makers is strongly dependent on a proper conduct of the LCA. How has LCA been applied until now? Are there any inconsistencies in the past practice? To answer these questions, we draw on a critical review of 222 published LCA studies of solid waste management systems. We analyse the past practice against the ISO standard requirements and the ILCD Handbook guidelines for each major step within the goal definition, scope definition, inventory analysis, impact assessment, and interpretation phases of the methodology. Results show that malpractices exist in several aspects of the LCA with large differences across studies. Examples are a frequent neglect of the goal definition, a frequent lack of transparency and precision in the definition of the scope of the study, e.g. an unclear delimitation of the system boundaries, a truncated impact coverage, difficulties in capturing influential local specificities such as representative waste compositions into the inventory, and a frequent lack of essential sensitivity and uncertainty analyses. Many of these aspects are important for the reliability of the results. For each of them, we therefore provide detailed recommendations to practitioners of waste management LCAs.

  20. Siting a municipal solid waste disposal facility, part II: the effects of external criteria on the final decision.

    Korucu, M Kemal; Karademir, Aykan


    The procedure of a multi-criteria decision analysis supported by the geographic information systems was applied to the site selection process of a planning municipal solid waste management practice based on twelve different scenarios. The scenarios included two different decision tree modes and two different weighting models for three different area requirements. The suitability rankings of the suitable sites obtained from the application of the decision procedure for the scenarios were assessed by a factorial experimental design concerning the effect of some external criteria on the final decision of the site selection process. The external criteria used in the factorial experimental design were defined as "Risk perception and approval of stakeholders" and "Visibility". The effects of the presence of these criteria in the decision trees were evaluated in detail. For a quantitative expression of the differentiations observed in the suitability rankings, the ranking data were subjected to ANOVA test after a normalization process. Then the results of these tests were evaluated by Tukey test to measure the effects of external criteria on the final decision. The results of Tukey tests indicated that the involvement of the external criteria into the decision trees produced statistically meaningful differentiations in the suitability rankings. Since the external criteria could cause considerable external costs during the operation of the disposal facilities, the presence of these criteria in the decision tree in addition to the other criteria related to environmental and legislative requisites could prevent subsequent external costs in the first place.

  1. Physico-chemical properties of Brazilian cocoa butter and industrial blends. Part I Chemical composition, solid fat content and consistency

    Ribeiro, A. P. B.


    Full Text Available A comparative study of the primary properties of six cocoa butter samples, representative of industrial blends and cocoa butter extracted from fruits cultivated in different geographical areas in Brazil is presented. The samples were evaluated according to fatty acid composition, triacylglycerol composition, regiospecific distribution, melting point, solid fat content and consistency. The results allowed for differentiating the samples according to their chemical compositions, thermal resistance properties, hardness characteristics, as well as technological adequacies and potential use in regions with tropical climates.

    En este trabajo se presenta un estudio comparativo de las propiedades primarias de mantecas de cacao, representativas de las mezclas industriales, y de la manteca de cacao original de diferentes zonas geográficas de Brasil. Las muestras fueron evaluadas de acuerdo a la composición de ácidos grasos, composición de triglicéridos, distribución de los ácidos grasos en las moléculas de triglicéridos, punto de fusión, contenido de grasa sólida y consistencia. Los resultados permitieron diferenciar las muestras por su composición química, propiedades de resistencia térmica, características de dureza, así como en materia de adecuaciones tecnológicas y los usos potenciales en las regiones de clima tropical.

  2. Research on Friction Properties of Mineral Lubricants in Thin-Film-Lubricating Regime

    Zhang Jie; Guan Tingting; Piao Jicheng


    On the basis of thin iflm lubrication theory, the inlfuence of lfuid iflm (disordered iflm), ordered iflm and ad-sorbed iflm on tribological behavior of lubricating oil in thin-iflm lubrication (TFL) regime was studied. Theμ-L (friction coefifcient versus load) curves of different oil viscosity and additive dosage were obtained by a high frequency reciprocat-ing test rig and the adsorption capacity of additive on steel surface were measured by QCM-D. Based on the Stribeck curve and thin iflm lubrication theory model, some conclusions can be drawn up, namely:(1) Theμ-L curves and the parameters of L0 andμ0, obtained from the high frequency reciprocating test rig with ball-disc contact, can be used to study tribologi-cal behaviors of lubricating oil under TFL conditions. (2) In comparison with the high viscosity base lfuid, the lower one can enter into TFL regime under lower load and keeps a lower friction coefifcient in TFL regime. (3) The polar molecules in additive formulation produce ordered adsorbed layer on steel surface to reduce friction coefifcient. And in TFL regime, the molecule’s polarity, layer thickness and saturation degree on steel surface probably can inlfuence lubricant’s tribological behaviors between the moving interfaces. Moreover, the further study would be focused on the competitive adsorption of different additives, the formation of dual-and/or tri-molecular adsorption layers, and other aspects.

  3. Dual Functional Star Polymers for Lubricants

    Cosimbescu, Lelia; Robinson, Joshua W.; Zhou, Yan; Qu, Jun


    Star-shaped poly(alkyl methacrylate)s (PAMAs) with a 3-arm architecture were designed, prepared and their performance as a dual additive (viscosity index improver and friction modifier) for engine oils was evaluated. Furthermore, the structure-property relationships between macromolecular structure and lubricant performance were studied. Several co-polymers of dodecylmethacrylate with polar methacrylates in various amounts and various topologies, were synthesized as model compounds. Star polymers with a polar content of at least 10% effectively reduced the friction coefficient in both mixed and boundary lubrication regime only in block or tapered block topology. However, a polar content of 20% was efficient in reducing friction in both random and block topologies.

  4. Thermal elastohydrodynamic lubrication of spur gears

    Wang, K. L.; Cheng, H. S.


    An analysis and computer program called TELSGE were developed to predict the variations of dynamic load, surface temperature, and lubricant film thickness along the contacting path during the engagement of a pair of involute spur gears. The analysis of dynamic load includes the effect of gear inertia, the effect of load sharing of adjacent teeth, and the effect of variable tooth stiffness which are obtained by a finite-element method. Results obtained from TELSGE for the dynamic load distributions along the contacting path for various speeds of a pair of test gears show patterns similar to that observed experimentally. Effects of damping ratio, contact ratio, tip relief, and tooth error on the dynamic load were examined. In addition, two dimensionless charts are included for predicting the maximum equilibrium surface temperature, which can be used to estimate directly the lubricant film thickness based on well established EHD analysis.

  5. High temperature lubricant screening and systems studies

    Jones, D. A.


    Four candidate lubricants for next generation aircraft gas turbine application were tested under open atmosphere conditions in a rig simulating an advanced engine 125 mm bore mainshaft thrust bearing position. Testing was conducted at speeds to 24,000 rpm (3,000,000 bearing DN), bearing ring temperature of 500 F, and with 1200 F air and 100 psi differential pressure across the seals installed in a dual tandem arrangement. Test bearing was a 125 mm bore split inner ring, outer race riding angular contact ball bearing under a 3280 lb. thrust load. One lubricant, a type 2 ester, performed extremely well. The mainshaft seal limited the performance. Numerous design improvements for this seal were indicated.

  6. Lubricant additive concentrate containing isomerized jojoba oil

    Arndt, G.


    This patent describes a crankcase motor oil additive concentrate intended to be added to a conventional crankcase motor oil to improve its ability to lubricate and protect the engine. The additive concentrate comprises the following components: A petroleum base stock of lubricating quality and viscosity. The base stock comprises from about 13.5 to 90 weight percent of the additive concentrate; a detergent-inhibitor package. The package is present at from about 7 to about 40 weight percent of the concentrate; a supplemental antiwear additive selected from the salts of dialkyl dithiophosporic acids. The additive is present at a level of from about 1 to about 10 weight percent of the concentrate; and a supplemental antiwear additive selected from the class of sulfurized olefins. The additive is present at a level of from about 1 to about 10 weight percent of the concentrate.

  7. Formation dry-out from CO2 injection into saline aquifers: Part 1, Effects of solids precipitation and their mitigation

    Pruess, Karsten; Muller, Nadja


    Injection of CO{sub 2} into saline aquifers may cause formation dry-out and precipitation of salt near the injection well, which may reduce formation porosity, permeability, and injectivity. This paper uses numerical simulation to explore the role of different processes and parameters in the salt precipitation process and to examine injection strategies that could mitigate the effects. The main physical mechanisms affecting the dry-out and salt precipitation process include (1) displacement of brine away from the injection well by injected CO{sub 2}, (2) dissolution (evaporation) of brine into the flowing CO{sub 2} stream, (3) upflow of CO{sub 2} due to gravity effects (buoyancy), (4) backflow of brine toward the injection point due to capillary pressure gradients that oppose the pressure gradient in the CO{sub 2}-rich ('gas') phase, and (5) molecular diffusion of dissolved salt. The different mechanisms operate on a range of spatial scales. CO{sub 2} injection at constant rate into a homogeneous reservoir with uniform initial conditions is simulated in 1-D radial geometry, to resolve multiscale processes by taking advantage of the similarity property, i.e., the evolution of system conditions as a function of radial distance R and time t depends only on the similarity variable R{sup 2}/t. Simulations in 2-D vertical cross sections are used to examine the role of gravity effects. We find that counterflow of CO{sub 2} and brine can greatly increase aqueous phase salinity and can promote substantial salt precipitation even in formations with low dissolved solids. Salt precipitation can accentuate effects of gravity override. We find that injecting a slug of fresh water prior to commencement of CO{sub 2} injection can reduce salt precipitation and permeability loss near the injection well.

  8. Rubber friction on (apparently) smooth lubricated surfaces

    Mofidi, M; Prakash, B [Division of Machine Elements, Luleaa University of Technology, Luleaa SE-97187 (Sweden); Persson, B N J [IFF, FZ-Juelich, 52425 Juelich (Germany); Albohr, O [Pirelli Deutschland AG, 64733 Hoechst/Odenwald, Postfach 1120 (Germany)


    We study rubber sliding friction on hard lubricated surfaces. We show that even if the hard surface appears smooth to the naked eye, it may exhibit short-wavelength roughness, which may make the dominant contribution to rubber friction. That is, the observed sliding friction is mainly due to the viscoelastic deformations of the rubber by the counterface surface asperities. The results presented are of great importance for rubber sealing and other rubber applications involving (apparently) smooth surfaces.

  9. Rubber friction on (apparently) smooth lubricated surfaces

    Mofidi, M.; Prakash, B.; Persson, B. N. J.; Albohr, O.


    We study rubber sliding friction on hard lubricated surfaces. We show that even if the hard surface appears smooth to the naked eye, it may exhibit short-wavelength roughness, which may make the dominant contribution to rubber friction. That is, the observed sliding friction is mainly due to the viscoelastic deformations of the rubber by the counterface surface asperities. The results presented are of great importance for rubber sealing and other rubber applications involving (apparently) smooth surfaces.

  10. Liposomes as lubricants: beyond drug delivery.

    Goldberg, Ronit; Klein, Jacob


    In this paper we review recent work (Goldberg et al., 2011a,b) on a new use for phosphatidylcholine liposomes: as ultra-efficient boundary lubricants at up to the highest physiological pressures. Using a surface force balance, we have measured the normal and shear interactions as a function of surface separation between layers of hydrogenated soy phophatidylcholine (HSPC) small unilamellar vesicles (SUVs) adsorbed from dispersion, at both pure water and physiologically high salt concentrations of 0.15 M NaNO(3). Cryo-Scanning Electron Microscopy shows each surface to be coated by a close-packed HSPC-SUV layer with an over-layer of liposomes on top. The shear forces reveal strikingly low friction coefficients down to 2×10(-5) in pure water system or 6×10(-4) in the 150 mM salt system, up to contact pressures of at least 12 MPa (pure water) or 6 MPa (high salt), comparable with those in the major joints. This low friction is attributed to the hydration lubrication mechanism arising from rubbing of the highly hydrated phosphocholine-headgroup layers exposed at the outer surface of each liposome, and provides support for the conjecture that phospholipids may play a significant role in biological lubrication.

  11. Molecular dynamics simulations of elasto-hydrodynamic lubrication and boundary lubrication for automotive tribology

    Washizu, Hitoshi [Toyota Central R and D Labs., Inc. Nagakute, Aichi 480-1192 (Japan); Sanda, Shuzo [Toyota Central R and D Labs., Inc. Nagakute, Aichi 480-1192 (Japan); Hyodo, Shi-aki [Toyota Central R and D Labs., Inc. Nagakute, Aichi 480-1192 (Japan); Ohmori, Toshihide [Toyota Central R and D Labs., Inc. Nagakute, Aichi 480-1192 (Japan); Nishino, Noriaki [Toyota Motor Corporation, 1 Toyota-cho, Toyota, Aichi 471-8572 (Japan); Suzuki, Atsushi [Toyota Motor Corporation, 1 Toyota-cho, Toyota, Aichi 471-8572 (Japan)


    Friction control of machine elements on a molecular level is a challenging subject in vehicle technology. We describe the molecular dynamics studies of friction in two significant lubrication regimes. As a case of elastohydrodynamic lubrication, we introduce the mechanism of momentum transfer related to the molecular structure of the hydrocarbon fluids, phase transition of the fluids under high pressure, and a submicron thickness simulation of the oil film using a tera-flops computer. For boundary lubrication, the dynamic behavior of water molecules on hydrophilic and hydrophobic silicon surfaces under a shear condition is studied. The dynamic structure of the hydrogen bond network on the hydrophilic surface is related to the low friction of the diamond-like carbon containing silicon (DLC-Si) coating.

  12. Molecular dynamics simulations of elasto-hydrodynamic lubrication and boundary lubrication for automotive tribology

    Washizu, Hitoshi; Sanda, Shuzo; Hyodo, Shi-aki; Ohmori, Toshihide; Nishino, Noriaki; Suzuki, Atsushi


    Friction control of machine elements on a molecular level is a challenging subject in vehicle technology. We describe the molecular dynamics studies of friction in two significant lubrication regimes. As a case of elastohydrodynamic lubrication, we introduce the mechanism of momentum transfer related to the molecular structure of the hydrocarbon fluids, phase transition of the fluids under high pressure, and a submicron thickness simulation of the oil film using a tera-flops computer. For boundary lubrication, the dynamic behavior of water molecules on hydrophilic and hydrophobic silicon surfaces under a shear condition is studied. The dynamic structure of the hydrogen bond network on the hydrophilic surface is related to the low friction of the diamond-like carbon containing silicon (DLC-Si) coating.

  13. Influence of electric double layer on thin film lubrication and elastohydrodynamic lubrication


    In the present paper, the influence of electric double layer (EDL) on thin film lubricationand elastohydrodynamic lubrication is studied. With modified Reynolds equation for electric doublelayer, the effect of zeta-potential on the film thickness and pressure is numerically calculated. Theresults show that the influence of electric double layer on the lubrication film thickness is significantonly for thin film. The minimum film thickness will increase greatly if the influence of EDL is con-sidered. As the initial film thickness increases, the effect will greatly decrease. The existence ofEDL will decrease the friction coefficient of the lubrication film. Furthermore, the above tendency isstill applicable even if the materials of the friction pair are different.

  14. Military Aviation Fluids and Lubricants Workshop 2006 (Postprint)


    and Processes • MEMS and Nano Contact Lubrication • Health Monitoring of Aircraft Components • Space Protective Coatings • Space Lubricant Technology...gas – Diesel fuel, heating fuel, mogas, E-85, biodiesel fuel • Packaged petroleum products & chemicals – Lubricating oils – Hydraulic fluids...628 Bubble Point Tests • 231 Immersion Tests • 155 Cold Start Tests • 11 Flow Fatigue Tests • 11 Collapse Tests • 9 Media Migration Tests • 34 ISO-23369




    Full Text Available In recent years, there has been development of the structure of thrust bearing with magnetic fluids . The essence of this type of bearing is to maintain a liquid lubricant in a very narrow gap with magnetic fluid by a magnetic field. Such systems can act as the bearing lubrication and sealing. This paper presents description of the experimental apparatus for examination magnetic fluid lubricated thrust bearing. Description of the construction and characteristics of the measuring possibilities ware presented.

  16. New lubrication concepts for environmental friendly machines. Tribological, thermophysical and viscometric properties of lubricants interacting with triboactive materials

    Schmidt, R.; Klingenberg, G. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Woydt, M. [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)


    The present research report was elaborated in close cooperation with Renault SAS, FUCHS Petrolub AG and Ingenieurgesellschaft Auto und Verkehr (IAV). The use of alternative oils for the lubrication of automobile engines has a potential of ecological and technical advantages. It requires the detailed knowledge of several thermophysical and viscometric properties in a large temperature range (mapping). Therefore, the following properties of up to twenty-eight different oils have been measured in the temperature range from 22 C to 150 C: density, heat capacity, thermal conductivity, viscosity at ambient pressure, viscosity under shear rates above 10{sup 6} s{sup -1}, and the viscosity at elevated pressures (maximum 100 MPa). The last two have been measured with a substantially improved and a newly developed apparatus, respectively. The pressure-viscosity coefficient has been measured on four hydrocarbon-based, factory-fill oils, a paraffin oil and twenty-three alternative oils. Nine of the alternative oils are based partly or completely on esters, the other fourteen on polyglycols, two of them additionally on water. Based on the piston ring/cylinder liner simulation tests of BAM performed outside of engines and the SRV {sup registered} tests both performed only under conditions of mixed/boundary lubrication, it is reasonable that thermally sprayed TiO{sub x}-based, Ti{sub n-2}Cr{sub 2}O{sub 2n-1} and (Ti,Mo)(C,N)+23NiMo piston ring coatings, so called 'lubricious or triboactive oxides', can substitute common materials and serve as a promising alternative to commercial piston ring coatings made of strategic Molybdenum and super-finishing intensive blends of WC/Cr{sub 3}C{sub 2}. Some couples qualified for 'zero' wear. In combination with bionotox ester- and polyglycol-based lubricants the coefficient of friction can be reduced fulfilling simultaneously stronger European exhaust emission regulations. Thermally sprayed Ti-based coatings with their

  17. Effects of Process Parameters on Fabrication of 2D- C f/Al Composite Parts by Liquid-Solid Extrusion Following the Vacuum Infiltration Technique

    Ma, Y. Q.; Qi, L. H.; Zhou, J. M.; Zhang, T.; Li, H. J.


    Two-dimensional, carbon-fiber-reinforced aluminum matrix composites (2D- C f/Al composites) were prepared using liquid-solid extrusion by following the vacuum infiltration technique (LSEVI), which was an integrated and comprehensive process that resulted in as composite special-shaped part with ideal infiltration and a satisfied forming effect. According to the current research, we found preheating temperature, squeeze temperature, squeeze pressure, and melting temperature were the key parameters of the LSEVI technique, and it was very important to optimize these process parameters to obtain the ideal composite part. Through the research of orthogonal experimental design of these process parameters, results showed that squeeze pressure was the most significant influence parameter, and optimized parameters of aforementioned parameters were 888 K, 893 K, and 1053 K (615 °C, 620 °C, and 780 °C), 70 MPa, respectively. An infiltration effect of the C f/Al composite was full and uniform, and preparation defects could be avoided effectively under the above process parameters. Two-dimensional (2D) T300 carbon fiber preform was prepared by the method of carbon fiber laminates, and the 2D- C f/Al composite special-shaped part was fabricated successfully using the former optimized parameters of LSEVI. Results indicated a forming effect of the special-shaped part was obtained and that its sizes were reasonable. Through the analyses of microstructure and tensile property test, its infiltration effect and fracture morphology were satisfied. Carbon fibers in the composite played the reinforced effect effectively, so the ultimate tensile strength of the composite part was improved by 115.8 pct than that of the matrix, which proved that the optimized process parameters of the LSEVI technique were reasonable.

  18. Lubricants for wind power plants. Gear oils. Requirements and properties; Schmierstoffe fuer Windenergieanlagen. Getriebeoele. Anforderungen und Eigenschaften

    Bock, Wolfgang [Fuchs Europe Schmierstoffe GmbH, Mannheim (Germany)


    Alternative energy supply is in the focus and in the discussion world-wide. Electrical energy coming from wind power plants is an important part in the energy supply chain. The lubricants used in wind power plants are often special lubricants, developed for the specific requirements of the application. The range of lubricants included adhesive lubricants, greases, pastes, hydraulic fluids, gear and lubricating oils as well as other specialities. Besides the greases and the hydraulic oils, the gear oil is the most important lubricant in wind power plants. The gear oil is used in the main gear of a wind power plant or in the Azimut gear sets. The lubricant has to be developed to match the requirements of the gear set, the tooth sets, the bearings, the seals, paints, etc. The gear oil has to fulfil the requirements according to DIN 51517, part 3 - CLP / CKC industrial gear oils, and in addition the specific requirements of gear and bearing manufacturers according to wind power plant specifications have to be fulfilled. The presentation ''Lubricants for Wind Power Plants - Requirements and Properties'' gives an overview of the industrial gear oils market, the classification of gear oils according to German and international standards is presented, and it describes the properties of a fully synthetic industrial gear oil based on polyalphaolefin which was especially developed for the main gear unit in wind power plants. The mechanical-dynamic tests for gear oils used in wind power plants (anti-scuffing properties, roller bearing wear protection, micro-pitting protection) are presented, together with the specific tests required by world-wide known bearing manufacturers. In addition the presentation shows test results of low speed wear tests. Compatibility tests with elastomers and sealing materials and the low temperature properties of fully synthetic gear oils based on polyalphaolefin are also discussed. The industrial gear oils for wind power plants


    The report gives results of miscibility, solubility, and viscosity measurements of refrigerant R-236ea with three potential lubricants. (NOTE: The data were needed to determine the suitability of refrigerant/lubricant combinations for use in refrigeration systems.) The lubricants...

  20. Removal of ammonia nitrogen from leachate of Muribeca municipal solid waste landfill, Pernambuco, Brazil, using natural zeolite as part of a biochemical system.

    Lins, Cecilia Maria M S; Alves, Maria Cristina M; Campos, Juacyara C; Silva, Fabrícia Maria S; Jucá, José Fernando T; Lins, Eduardo Antonio M


    The inadequate disposal of leachate is one of the key factors in the environmental impact of urban solid waste landfills in Brazil. Among the compounds present in the leachates from Brazilian landfills, ammonia nitrogen is notable for its high concentrations. The purpose of this study was to assess the efficiency of a permeable reactive barrier filled with a natural zeolite, which is part of a biochemical system for the tertiary treatment of the leachate from Muribeca Municipal Solid Waste Landfill in Pernambuco, Brazil, to reduce its ammonia nitrogen concentration. This investigation initially consisted of kinetic studies and batch equilibrium tests on the natural zeolite to construct the sorption isotherms, which showed a high sorption capacity, with an average of 12.4 mg NH4+.L(-1), a value close to the sorption rates found for the aqueous ammonium chloride solution. A permeable reactive barrier consisting of natural zeolite, as simulated by the column test, was efficient in removing the ammonia nitrogen present in the leachate pretreated with calcium hydroxide. Nevertheless, the regenerated zeolite did not satisfactorily maintain the sorption properties of the natural zeolite, and an analysis of their cation-exchange properties showed a reduced capacity of 54 meq per 100 g for the regenerated zeolite compared to 150 meq per 100 g for the natural zeolite.