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Sample records for active lubrication applied

  1. Schemes for applying active lubrication to main engine bearings

    Estupinan, Edgar Alberto; Santos, Ilmar

    2009-01-01

    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 and...... 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...... 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...

  2. Actively lubricated bearings applied as calibrated shakers to aid parameter identification in rotordynamics

    Santos, Ilmar; Cerda Varela, Alejandro Javier

    2013-01-01

    between hydrodynamic, hydrostatic and controllable lubrication regimes, can be used either to control or to excite rotor lateral vibrations. An accurate characterization of the active oil film forces is of fundamental importance to elucidate the feasibility of applying the active lubrication as non......-invasive perturbation forces, or in other words, as a "calibrated shaker", to perform in-situ rotordynamic tests. The main original contributions of this paper are three: a) the experimental characterization of the active fluid film forces generated in an actively-lubricated tilting-pad journal bearing in the frequency...... systems; c) experimental indication of how small such active fluid film forces (perturbation forces) should be, in order to perturb the rotor-journal bearing system without significantly changing its dynamic characteristics. To validate the experimental procedure and results obtained via actively-lubricated...

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

    Nicoletti, Rodrigo; Santos, Ilmar

    2003-01-01

    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 further reduction of shaft vibrations one can count with the active lubrication action, which is based on injecting pressurised oil into the bearing gap through orifices machined in the bearing sliding surface. The design and efficiency of some linear (PD, PI and PID) and non-linear controllers, applied...... vibration reduction of unbalance response of a rigid rotor, where the PD and the non-linear P controllers show better performance for the frequency range of study (0 to 80 Hz). The feasibility of eliminating rotor-bearing instabilities (phenomena of whirl) by using active lubrication is also investigated...

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

    Nicoletti, Rodrigo; Santos, Ilmar

    2003-01-01

    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...... further reduction of shaft vibrations one can count with the active lubrication action, which is based on injecting pressurised oil into the bearing gap through orifices machined in the bearing sliding surface. The design and efficiency of some linear (PD, PI and PID) and non-linear controllers, applied...... to a tilting-pad journal bearing, are analysed and discussed. Important conclusions about the application of integral controllers, responsible for changing the rotor-bearing equilibrium position and consequently the "passive" oil film damping coefficients, are achieved. Numerical results show an...

  5. Linear and non-linear control techniques applied to actively lubricated journal bearings

    Nicoletti, R.; Santos, I. F.

    2003-03-01

    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 use the conventional hydrodynamic lubrication. For further reduction of shaft vibrations one can use the active lubrication action, which is based on injecting pressurized oil into the bearing gap through orifices machined in the bearing sliding surface. The design and efficiency of some linear (PD, PI and PID) and a non-linear controller, applied to a tilting-pad journal bearing, are analysed and discussed. Important conclusions about the application of integral controllers, responsible for changing the rotor-bearing equilibrium position and consequently the "passive" oil film damping coefficients, are achieved. Numerical results show an effective vibration reduction of unbalance response of a rigid rotor, where the PD and the non-linear P controllers show better performance for the frequency range of study (0-80 Hz). The feasibility of eliminating rotor-bearing instabilities (phenomena of whirl) by using active lubrication is also investigated, illustrating clearly one of its most promising applications.

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

    Pierart, Fabián G.; Santos, Ilmar F.

    2016-01-01

    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...... combines three main domains: tribology, dynamics and control. The Reynolds equation with radial injection, including piezoelectrically controlled jet, describes the non-linear interaction between bearing surface and rotating shaft. Dynamics of the flexible shaft and rotating parts are modelled aid 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....

  7. Active lubrication applied to internal combustion engines - evaluation of control strategies

    Estupinan, Edgar Alberto; Santos, Ilmar

    2009-01-01

    The performance of fluid film bearings in a combustion engine affects key functions such as durability, noise and vibration. Therefore, this work evaluates different control strategies for applying active radial oil injection in the main bearings of internal combustion engines with the aim of...... reducing friction losses and vibrations between the crankshaft and the bearings. The conventional hydrodynamic lubrication is combined with hydrostatic lubrication which is actively modified by radially injecting oil at controllable pressures, through orifices circumferentially located around the bearing...... surface. The behaviour of a main bearing of a medium size combustion engine, operating with radial oil injection and with four different control strategies is analyzed, giving some insights into the minimum fluid film thickness, maximum fluid film pressure, friction losses and maximum vibration levels...

  8. Feasibility of Applying Active Lubrication to Dynamically Loaded Fluid Film Bearings

    Estupinan, Edgar Alberto; Santos, Ilmar

    2009-01-01

    The feasibility of modifying the dynamics of the thin fluid films of dynamically loaded journal bearings, using different strategies of active lubrication is studied in this work. A significant reduction in the vibration levels, wear and power friction losses, is expected. Particularly, the focus...... of this study is on the analysis of main crankshaft bearings, where the conventional hydrodynamic lubrication is modified by injecting oil at actively controllable pressures, through orifices circumferentially located along the bearing surface....

  9. Tilting-Pad Journal Bearings with Active Lubrication Applied as Calibrated Shakers: Theory and Experiment

    Cerda Varela, Alejandro Javier; Santos, Ilmar

    2014-01-01

    In recent years, a continuous research effort has transformed the conventional tilting-pad journal bearing into a mechatronic machine element. The addition of electromechanical elements provides the possibility of generating controllable forces over the rotor as a function of a suitable control...... dependent calibration function, i.e. the transfer function between control signal and force over the rotor. This work presents a theoretical model of the calibration function for a tilting-pad journal bearing with active lubrication. The bearing generates controllable forces by injecting pressurized oil...... signal. Such forces can be applied in order to perform parameter identification procedures in-situ, which enables evaluation of the mechanical condition of the machine in a non-invasive way. The usage of a controllable bearing as a calibrated shaker requires obtaining the bearing specific frequency...

  10. Feasibility of Applying Active Lubrication to Reduce Vibration in Industrial Compressors

    Santos, Ilmar; Nicoletti, Rodrigo; Scalabrin, A.

    2004-01-01

    the orifices distributed over the sliding surface. The dynamic coefficients of tilting-pad bearings with and without active lubrication and their influence on an industrial compressor of 391 Kg, which operates with a maximum speed of 10,200 rpm, are analyzed. In the original compressor design, the...... bearing housings are mounted on squeeze-film dampers in order to ensure reasonable stability margins during full load condition (high maximum continuous speed). Instead of having a combination of tilting-pad bearings and squeeze-film dampers, another design solution is proposed and theoretically......In this paper the complete set of modified Reynolds´ equations for the active lubrication is presented. The solution of such a set of equations allows the determination of stiffness and damping coefficients of actively lubricated bearings. These coefficients are not just dependent on Sommerfeld...

  11. Actively lubricated bearings applied as calibrated shakers to aid parameter identification in rotordynamics

    Santos, Ilmar; Cerda Varela, Alejandro Javier

    2013-01-01

    -invasive perturbation forces, or in other words, as a "calibrated shaker", to perform in-situ rotordynamic tests. The main original contributions of this paper are three: a) the experimental characterization of the active fluid film forces generated in an actively-lubricated tilting-pad journal bearing in the frequency......The servo valve input signal and the radial injection pressure are the two main parameters responsible for dynamically modifying the journal oil film pressure and generating active fluid film forces in controllable fluid film bearings. Such fluid film forces, resulting from a strong coupling...... domain and the application of such a controllable bearing as a calibrated shaker aiming at determining the frequency response function (FRF) of rotordynamic systems; b) experimental quantification of the influence of the supply pressure and servo valve input signal on the FRF of rotor-journal bearing...

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

    Morosi, Stefano; Santos, Ilmar

    2011-01-01

    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...

  13. Adjustable ETHD lubrication applied to the improvement of dynamic performance of flexible rotors supported by active TPJB

    Salazar, Jorge Andrés González; Cerda Varela, Alejandro Javier; Santos, Ilmar

    2013-01-01

    pressurized oil directly into the bearing clearance through a nozzle placed in a radial bore at the middle of the pad and connected to a high pressure supply unit by servovalves. The theoretical model is based on a finite element model, where the active TPJB with adjustable lubrication is included using...

  14. Feasibility of Applying Controllable Lubrication Techniques to Reciprocating Machines

    Pulido, Edgar Estupinan

    The use of active lubrication in journal bearings helps to enhance the thin fluid films by increasing the fluid film thickness and consequently reducing viscous friction losses and vibrations. One refers to active lubrication when conventional hydrodynamic lubrication is combined with dynamically...... conventional lubrication conditions, a mathematical model of a reciprocating mechanism connected to a rigid / flexible rotor via thin fluid films was developed. The mathematical model involves the use of multibody dynamics theory for the modelling of the reciprocating mechanism (rigid bodies), finite elements...... method for the modelling of the flexible rotor (crankshaft) and hydrodynamic fluid film theory for describing the dynamics of the thin fluid films. When active lubrication is introduced to modify conventional hydrodynamic lubrication, by means of aplying radial oil injection at controllable oil pressures...

  15. Three Types of Active Lubrication Systems for the Main Bearings of Reciprocating Machines

    Santos, Ilmar; Pulido, E. E.

    2010-01-01

    In the paper the authors investigate three different schemes for the realization of the controllable oil injection system to be couple to the main engine bearings. The use of active lubrication in fluid film bearings helps to enhance the hydrodynamic fluid film by increasing the fluid film...... engine, where the conventional lubrication of the main bearing is modified by applying radial oil injection. The performance of such a hybrid bearing is compared to an equivalent conventional lubricated bearing in terms of the maximum fluid film pressures, minimum fluid film thicknesses and reduction of...... thickness 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...

  16. Feasibility of Applying Controllable Lubrication to Dynamically Loaded Journal Bearings

    Estupinan, Edgar Alberto; Santos, Ilmar

    2009-01-01

    fluid films, based on fluid film theory. For a dynamically loaded journal bearing, the fluid film pressure distribution can be computed by numerically solving the Reynolds equation, by means of finite-difference method. Particularly, in this study the main focus is on the lubrication behavior of the...... reaction forces in a reciprocating compressor have a cyclic behavior, periodic oil pressure injection rules based on the instantaneous crank angle and load bearing condition can be established. In this paper, several bearing configurations working under different oil pressure injection rules conditions are...... analyzed. The behavior of the following parameters is investigated when the system operates with hybrid controllable lubrication conditions: a) maximum fluid film pressure, b) minimum fluid film thickness, c) maximum vibration levels and d) injection oil pressures....

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

    Nicoletti, Rodrigo; Santos, Ilmar

    2005-01-01

    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 inserted...... active lubricated tilting-pad bearing. By applying a simple proportional controller it is possible to reach 30% reduction of the resonance peak associated with the first rigid body mode shape of the system. One of the most important consequences of such a vibration reduction in rotating machines is the...

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

    Nicoletti, Rodrigo; Santos, Ilmar

    2004-01-01

    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 inserted...... lubricated tilting-pad bearing. By applying a simple proportional controller, it is possible to reach 30% reduction of the resonance peak associated with the first rigid body mode shape of the system. One of the most important consequences of such a vibration reduction in rotating machines is the feasibility...

  19. Liquid-liquid extraction and adsorption on solid surfaces applied to used lubricant oils recovery

    J. L. Assunção Filho

    2010-12-01

    Full Text Available In this work, the recovery of base oils from waste lubricants following the steps of solvent extraction, adsorption on solids and solvent removal by evaporation was evaluated. In the step of solvent extraction, the most efficient was 1-butanol, followed by tert-butanol, 2-propanol and ethanol; for the step of adsorption, activated carbon was the most effective solid for PAH removal, confirming the similarity of these compounds with petroleum aromatic fractions. Thus, the optimum solvent-adsorbent pair for the recovery of used lubricant oils through the proposed methodology was 1-butanol/activated carbon. At the end of the process, it was possible to establish a set of steps that permit the recovery of lubricant base oils with lower content of contaminants.

  20. Load-Induced Confinement Activates Diamond Lubrication by Water

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

    2013-10-01

    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.

  1. Liquid-liquid extraction and adsorption on solid surfaces applied to used lubricant oils recovery

    J. L. Assunção Filho; L. G. M. Moura; A.C.S. RAMOS

    2010-01-01

    In this work, the recovery of base oils from waste lubricants following the steps of solvent extraction, adsorption on solids and solvent removal by evaporation was evaluated. In the step of solvent extraction, the most efficient was 1-butanol, followed by tert-butanol, 2-propanol and ethanol; for the step of adsorption, activated carbon was the most effective solid for PAH removal, confirming the similarity of these compounds with petroleum aromatic fractions. Thus, the optimum solvent-adsor...

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

    Santos, Ilmar; Watanabe, F.Y.

    2004-01-01

    Fluid film forces are generated in hydrostatic journal bearings by two types of lubrication mechanisms: the hydrostatic lubrication in the bearing recesses and hydrodynamic lubrication in the bearing lands, when operating in rotation. The combination of both lubrication mechanisms leads to hybrid...... 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....

  3. Experimental Identification of Dynamic Coefficients of Tilting-Pad Bearings with Active Lubrication

    Salazar, Jorge Andrés González; Cerda Varela, Alejandro Javier; Santos, Ilmar

    supply unit, b) servovalves, c) radial injection nozzles, d) displacement sensors and e) well-tuned digital controllers which turn the bearing static and dynamic properties controllable. A scaled-down industrial rotor, composed by a flexible rotor supported by a four rocker LBP tilting-pad journal......This article presents the experimental identification of the equivalent dynamic coefficients of an activelylubricated bearing under different lubrication regimes, namely: passive (no injection flow), hybrid (constant injection flow) and feedback-controlled (variable injection flow) lubrication. The...... bearing featuring active lubrication under light load conditions, is used for such a goal. The experimental identification is performed in the frequency domain by means of the measured FRFs and a finite element model of the rotor. The comparison between results under the different lubrication regimes...

  4. Lubrication fundamentals

    Pirro, DM

    2001-01-01

    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.

  5. Is wetter better? An evaluation of over-the-counter personal lubricants for safety and anti-HIV-1 activity.

    Dezzutti, Charlene S; Brown, Elizabeth R; Moncla, Bernard; Russo, Julie; Cost, Marilyn; Wang, Lin; Uranker, Kevin; Kunjara Na Ayudhya, Ratiya P; Pryke, Kara; Pickett, Jim; Leblanc, Marc-André; Rohan, Lisa C

    2012-01-01

    Because lubricants may decrease trauma during coitus, it is hypothesized that they could aid in the prevention of HIV acquisition. Therefore, safety and anti-HIV-1 activity of over-the-counter (OTC) aqueous- (n = 10), lipid- (n = 2), and silicone-based (n = 2) products were tested. The rheological properties of the lipid-based lubricants precluded testing with the exception of explant safety testing. Six aqueous-based gels were hyperosmolar, two were nearly iso-osmolar, and two were hypo-osmolar. Evaluation of the panel of products showed Gynol II (a spermicidal gel containing 2% nonoxynol-9), KY Jelly, and Replens were toxic to Lactobacillus. Two nearly iso-osmolar aqueous- and both silicone-based gels were not toxic toward epithelial cell lines or ectocervical or colorectal explant tissues. Hyperosmolar lubricants demonstrated reduction of tissue viability and epithelial fracture/sloughing while the nearly iso-osmolar and silicon-based lubricants showed no significant changes in tissue viability or epithelial modifications. While most of the lubricants had no measurable anti-HIV-1 activity, three lubricants which retained cell viability did demonstrate modest anti-HIV-1 activity in vitro. To determine if this would result in protection of mucosal tissue or conversely determine if the epithelial damage associated with the hyperosmolar lubricants increased HIV-1 infection ex vivo, ectocervical tissue was exposed to selected lubricants and then challenged with HIV-1. None of the lubricants that had a moderate to high therapeutic index protected the mucosal tissue. These results show hyperosmolar lubricant gels were associated with cellular toxicity and epithelial damage while showing no anti-viral activity. The two iso-osmolar lubricants, Good Clean Love and PRÉ, and both silicone-based lubricants, Female Condom 2 lubricant and Wet Platinum, were the safest in our testing algorithm. PMID:23144863

  6. Is wetter better? An evaluation of over-the-counter personal lubricants for safety and anti-HIV-1 activity.

    Charlene S Dezzutti

    Full Text Available Because lubricants may decrease trauma during coitus, it is hypothesized that they could aid in the prevention of HIV acquisition. Therefore, safety and anti-HIV-1 activity of over-the-counter (OTC aqueous- (n = 10, lipid- (n = 2, and silicone-based (n = 2 products were tested. The rheological properties of the lipid-based lubricants precluded testing with the exception of explant safety testing. Six aqueous-based gels were hyperosmolar, two were nearly iso-osmolar, and two were hypo-osmolar. Evaluation of the panel of products showed Gynol II (a spermicidal gel containing 2% nonoxynol-9, KY Jelly, and Replens were toxic to Lactobacillus. Two nearly iso-osmolar aqueous- and both silicone-based gels were not toxic toward epithelial cell lines or ectocervical or colorectal explant tissues. Hyperosmolar lubricants demonstrated reduction of tissue viability and epithelial fracture/sloughing while the nearly iso-osmolar and silicon-based lubricants showed no significant changes in tissue viability or epithelial modifications. While most of the lubricants had no measurable anti-HIV-1 activity, three lubricants which retained cell viability did demonstrate modest anti-HIV-1 activity in vitro. To determine if this would result in protection of mucosal tissue or conversely determine if the epithelial damage associated with the hyperosmolar lubricants increased HIV-1 infection ex vivo, ectocervical tissue was exposed to selected lubricants and then challenged with HIV-1. None of the lubricants that had a moderate to high therapeutic index protected the mucosal tissue. These results show hyperosmolar lubricant gels were associated with cellular toxicity and epithelial damage while showing no anti-viral activity. The two iso-osmolar lubricants, Good Clean Love and PRÉ, and both silicone-based lubricants, Female Condom 2 lubricant and Wet Platinum, were the safest in our testing algorithm.

  7. Active Lubrication: Feasibility and Limitations on Reducing Vibration in Rotating Machinery

    Nicoletti, Rodrigo; Santos, Ilmar

    2003-01-01

    In the present work, experimental results show the feasibility of reducing the amplitude of resonance peaks in rotor-bearing test rig, in the frequency domain, by using active lubricated bearings. The most important consequence of this vibration reduction in rotating machines is the feasibility o...

  8. Active Lubrication: Feasibility and Limitations on Reducing Vibration in Rotating Machinery

    Nicoletti, Rodrigo; Santos, Ilmar

    2004-01-01

    In the present work, experimental results show the feasibility of reducing the amplitude of resonance peaks in rotor-bearing test rig, in the frequency domain, by using active lubricated bearings. The most important consequence of this vibration reduction in rotating machines is the feasibility o...

  9. 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 inserted...... into the model by using two different approaches: (a) linearized active oil film forces and the assumption that the hydrodynamic forces and the active hydraulic forces can be decoupled; (b) equivalent dynamic coefficients of the active oil film and the solution of the modified Reynolds' equation for...... the active lubrication. The second approach based on the equivalent dynamic coefficients leads to more accurate results since it includes the frequency dependence of the active hydraulic forces. Theoretical and experimental results reveal the feasibility of reducing resonance peaks by using the active...

  10. Lubrication fundamentals

    This book is organized under the following headings: lubricating oils; lubricating greases; synthetic lubricants; machine elements; lubricant application; internal combustion engines; stationary gas turbines; steam turbines; hydraulic turbines; nuclear power plants; automotive chassis components; automotive power transmissions; compressors; handling, storing, and dispensing lubricants, in-plant handling for lubricant conservation

  11. Lubricants and lubrication

    Mang, T.; Dresel, W. [eds.] [Fuchs Petrolub AG, Mannheim (Germany)

    2001-07-01

    The use of lubricants is as old as mankind but the scientific analysis of lubrication, friction and wear, as an aspect of tribology is relatively new. Only recently have lubricants begun to be viewed as functional elements in engineering and this group of substances is also receiving increased attention from engineers. This book provides chemists and engineers with a clear interdisciplinary introduction and orientation to all major lubricant applications, focusing not only on the various products but also on specific application engineering criteria. (orig.)

  12. The Phan-Thien and Tanner model applied to thin film spherical coordinates: applications for lubrication of hip joint replacement.

    Tichy, John; Bou-Saïd, Benyebka

    2008-04-01

    The Phan-Thien and Tanner (PTT) model is one of the most widely used rheological models. It can properly describe the common characteristics of viscoelastic non-Newtonian fluids. There is evidence that synovial fluid in human joints, which also lubricates artificial joints, is viscoelastic. Modeling the geometry of the total hip replacement, the PTT model is applied in spherical coordinates for a thin confined fluid film. A modified Reynolds equation is developed for this geometry. Several simplified illustrative problems are solved. The effect of the edge boundary condition on load-carrying normal stress is discussed. Solutions are also obtained for a simple squeezing flow. The effect of both the relaxation time and the PTT shear parameter is to reduce the load relative to a Newtonian fluid with the same viscosity. This implies that the Newtonian model is not conservative and may overpredict the load capacity. The PTT theory is a good candidate model to use for joint replacement lubrication. It is well regarded and derivable from molecular considerations. The most important non-Newtonian characteristics can be described with only three primary material parameters. PMID:18412499

  13. Exploring integral controllers in actively-lubricated tilting-pad journal bearings

    Salazar, Jorge Andrés González; Santos, Ilmar

    2015-01-01

    Active tilting-pad journal bearings with radial oil injection combine good stability properties of conventional tilting-pad journal bearings with the capability of improving their dynamic properties even more by control techniques. The main contribution of this work is the experimental...... investigation of integral controllers for feedback-controlled lubrication with the aim of: a) presetting the static journal center and consequently exploring the changes of bearing dynamic properties; b) obtaining an integral controller capable of re-positioning the static journal eccentricity for matching...... equilibria under conventional hydrodynamic and feedback-controlled lubrication regimes. A novel application is proposed, that tries to build non-invasive perturbation forces and uses the active fluid film forces of the bearing as a calibrated shaker....

  14. Tribological Investigations of Hard-Faced Layers and Base Materials of Forging Dies with Different Kinds of Lubricants Applied

    V. Lazić

    2010-12-01

    Full Text Available This paper gives a procedure for choosing the right technology for reparative hard facing of damaged forging dies. Since they are subject to impact loads and cyclic temperature elevations, forging dies should be made of steel that is able to withstand great impact loads, maintain good mechanical properties at elevated temperatures and that is resistant to wear and thermal fatigue. For these reasons, forging dies are made of conditionally weldable alloy tool steels; however it makes hard facing of damaged tools even more difficult. In this paper, wear resistance of base materials, hard-faced layers and heat-affected zones are tribologically investigated when two different lubricants - pure synthetical oil LM 76 and LM 76 with 6% molybdenum disulfide (MoS2 are applied. Tribological investigations have shown that the wear resistance of the hard faced layers is considerably greater than the wear resistance of the base material. However, the base material has better properties concerning friction.

  15. Feasibility of Influencing the Dynamic Fluid Film Coefficients of a Multirecess Journal Bearing by means of Active Hybrid Lubrication

    Santos, Ilmar; Watanabe, F. Y.

    2003-01-01

    The main objective of this research project is the investigation of multirecess hydrostatic journal bearings with active hybrid (hydrostatic and hydrodynamic) lubrication. This paper gives a theoretical contribution to the modeling of this kind of bearing, combining computational fluid dynamics a...... significant modifications of active hybrid forces, which can be useful while reducing vibration and stabilizing rotating machines.......The main objective of this research project is the investigation of multirecess hydrostatic journal bearings with active hybrid (hydrostatic and hydrodynamic) lubrication. This paper gives a theoretical contribution to the modeling of this kind of bearing, combining computational fluid dynamics and...

  16. Comparative evaluation of tableting compression behaviors by methods of internal and external lubricant addition: Inhibition of enzymatic activity of trypsin preparation by using external lubricant addition during the tableting compression process

    Otsuka, Makoto; Sato, Mitsuyo; Matsuda, Yoshihisa

    2001-01-01

    This study evaluated tableting compression by using internal and external lubricant addition. The effect of lubricant addition on the enzymatic activity of trypsin, which was used as a model drug during the tableting compression process, was also investigated. The powder mixture (2% crystalline trypsin, 58% crystalline lactose, and 40% microcrystalline cellulose) was kneaded with 5% hydroxypropyl cellulose aqueous solution and then granulated using an extruding granulator equipped with a 0.5-...

  17. The Wear Characteristics of Heat Treated Manganese Phosphate Coating Applied to AlSi D2 Steel with Oil Lubricant

    Venkatesan Alankaram

    2012-12-01

    Full Text Available Today, in the area of material design conversion coatings play an important role in the applications where temperature, corrosion, oxidation and wear come in to play. Wear of metals occurs when relative motion between counter-surfaces takes place, leading to physical or chemical destruction of the original top layers. In this study, the tribological behaviour of heat treated Manganese phosphate coatings on AISI D2 steel with oil lubricant was investigated. The Surface morphology of manganese phosphate coatings was examined by Scanning Electron Microscope (SEM and Energy Dispersive X-ray Spectroscopy (EDX .The wear tests were performed in a pin on disk apparatus as per ASTM G-99 Standard. The wear resistance of the coated steel was evaluated through pin on disc test using a sliding velocity of 3.0m/s under Constant loads of 40 N and 100 N with in controlled condition of temperature and humidity. The Coefficient of friction and wear rate were evaluated. Wear pattern of Manganese phosphate coated pins with oil lubricant, Heat treated Manganese phosphate coated pins with oil lubricant were captured using Scanning Electron Microscope (SEM. The results of the wear test established that the heat treated manganese phosphate coating with oil lubricant exhibited the lowest average coefficient of friction and the lowest wear loss up to 6583 m sliding distance under 40 N load and 3000 m sliding distance even under 100 N load respectively. The Wear volume and temperature rise in heat treated Manganese Phosphate coated pins with oil lubricant is lesser than the Manganese Phosphate coated pins with oil lubricant

  18. Reduction of friction and wear by grooves applied on the nanoscale polished surface in boundary lubrication conditions

    Stelmakh, Alexander U.; Pilgun, Yuriy V.; Kolenov, Sergiy O.; Kushchev, Alexey V.

    2014-05-01

    The evolution of a friction surface geometry with initially directed microscale grooves on a nanoscale polished surface in ring-on-block sliding contact is studied experimentally. Reduced wear and friction is observed when the orientation of grooves coincides with the direction of sliding. A new compressive-vacuum hypothesis of friction force nature under a condition of boundary lubrication is proposed, which successfully explains the observed phenomena. Grooves supply lubricant into the contact zone and facilitate its devacuumization, which lead to substantial reduction of surface wear. The obtained results enable developing optimized roughness profiles of friction surfaces to create high-performance durable friction units.

  19. Is Wetter Better? An Evaluation of Over-the-Counter Personal Lubricants for Safety and Anti-HIV-1 Activity

    Dezzutti, Charlene S.; Brown, Elizabeth R.; Bernard Moncla; Julie Russo; Marilyn Cost; Lin Wang; Kevin Uranker; Kunjara Na Ayudhya, Ratiya P.; Kara Pryke; Jim Pickett; Marc-André Leblanc; Rohan, Lisa C.

    2012-01-01

    Because lubricants may decrease trauma during coitus, it is hypothesized that they could aid in the prevention of HIV acquisition. Therefore, safety and anti-HIV-1 activity of over-the-counter (OTC) aqueous- (n = 10), lipid- (n = 2), and silicone-based (n = 2) products were tested. The rheological properties of the lipid-based lubricants precluded testing with the exception of explant safety testing. Six aqueous-based gels were hyperosmolar, two were nearly iso-osmolar, and two were hypo-osmo...

  20. Lubrication background

    Hamrock, B. J.; Dowson, D.

    1981-01-01

    Surface topography, including the various physical methods of measuring surfaces, and the various lubrication regimes (hydrodynamic, elastohydrodynamic, boundary, and mixed) are discussed. The historical development of elastohydrodynamic lubrication is outlined. The major accomplishments in four periods, the pre-1950's, the 1950's, the 1960's, and the 1970's are presented.

  1. Lubrication a practical guide to lubricant selection

    Lansdown, A R

    1982-01-01

    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

  2. Lubrication by glycoprotein brushes.

    Zappone, Bruno; Ruths, Marina; Greene, George W.; Israelachvili, Jacob

    2006-03-01

    Grafted polyelectrolyte brushes show excellent lubricating properties under water and have been proposed as a model to study boundary lubrication in biological system. Lubricin, a glycoprotein of the synovial fluid, is considered the major boundary lubricant of articular joints. Using the Surface Force Apparatus, we have measured normal and friction forces between model surfaces (negatively charged mica, positively charged poly-lysine and aminothiol, hydrophobic alkanethiol) bearing adsorbed layers of lubricin. Lubricin layers acts like a versatile anti-adhesive, adsorbing on all the surfaces considered and creating a repulsion similar to the force between end-grafted polymer brushes. Analogies with polymer brushes also appear from bridging experiment, where proteins molecules are end-adsorbed on two opposing surfaces at the same time. Lubricin `brushes' show good lubricating ability at low applied pressures (P<0.5MPa), especially on negatively charged surfaces like mica. At higher load, the adsorbed layers wears and fails lubricating the surfaces, while still protecting the underlying substrate from wearing. Lubricin might thus be a first example of biological polyelectrolytes providing `brush-like' lubrication and wear-protection.

  3. Evaluating Solid-Lubricant Films

    Fusaro, Robert L.

    1988-01-01

    Report describes experimental techniques for measuring properties of solid-lubricant films. Discusses experimental parameters. Reviews basic pin-on-disk configurations and methods of preparing disks and applying solid lubricants. Techniques for constant-temperature testing, low-contact-stress testing, and temperature-versus-time testing presented. Suggests methods of measuring pin-wear volume and recommends ways of presenting data.

  4. Developments in lubricant technology

    Srivastava, S P

    2014-01-01

    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

  5. Potential of palm kernel activated carbon epoxy (PKAC-E composite as solid lubricant: Effect of load on friction and wear properties

    K.W. Chua

    2014-09-01

    Full Text Available The aim of this study is to investigate the effect of load on the friction and wear properties of palm kernel activated carbon epoxy (PKAC-E composite. The PKAC-E composite specimen was fabricated by hot compression molding method. Dry sliding test was performed by using a pin-on-disc tribometer at various load conditions with constant sliding speed and distance. The experimental results show that wear rate and friction coefficient of PKAC-E composite decreases with applied load. However, at higher load, friction coefficient increases slightly and remains almost invariant with applied load. In addition, some adhesive and abrasive wear types were identified on the worn surfaces. The main conclusion of this work is that PKAC-E composite show unique properties as solid lubricant at low load under unlubricated conditions.

  6. 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.

  7. Active system monitoring applied on wind turbines

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad; Parbo, Henrik;

    2009-01-01

    A concept for active system monitoring (ASM) applied on wind turbines is presented in this paper. The concept is based on an injection of a small periodic auxiliary signal in the system. An investigation of the signature from the auxiliary input in residual (error) signals can then be applied for...

  8. Computational Chemistry and Lubrication

    Zehe, Michael J.

    1998-01-01

    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.

  9. Control system design for flexible rotors supported by actively lubricated bearings

    Nicoletti, Rodrigo; Santos, Ilmar

    2008-01-01

    and keeping the lengths of the two eigenvalues constant in the real-imaginary plane. The methodology is applied to an industrial gas compressor supported by active tilting-pad journal bearings. The unbalance response functions and mode shapes of the flexible rotor with and without active control are...... displacement and velocity of the shaft at the bearing positions....

  10. Vibration active control of tilting pad journal bearing rotor system based on the active lubrication%基于主动润滑可倾瓦轴承转子系统的振动主动控制

    刘宏; 宫晓春; 王晋麟

    2011-01-01

    研究一类可倾瓦支承的单盘非对称转子系统的振动主动控制问题.首先建立了系统的非线性动力学方程,针对主动润滑控制系统设计了BP神经网络PID控制器对转子系统进行振动主动控制.通过计算分析可知,采用基于BP-PID的主动润滑系统能够很好的抑制系统的振幅,使系统在很高的转速时才发生油膜失稳,拓宽转子系统稳定运转的转速范围,在转子系统发生油膜失稳时系统的振幅也能够得到极大程度的控制.%The vibration active control of an unsymmetrical rotor supported by two tilting pad journal bearings is investigated in this paper. Firstly, the nonlinear governing equation of the rotor system is formulated. Then the BP neural network PID controller is designed with regard to the active lubricated control system is applied to suppress the vibration of the concerning rotor system. After calculation and analysis the persuasive results are obtained. The vibration amplitude of the rotor system is greatly reduced by means of the active lubricated control system through the BP neural network PID controller. The whip instability of the controlled system occurs at a very high rotational speed and the stable operation range is greatly broadened. The vibration amplitude can be significantly suppressed by the active lubricated control system when the rotor runs up against the whip instability.

  11. 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.

  12. Tractor Mechanics. Maintaining and Servicing the Engine, Learning Activity Packages 78-89; Lubricating the Tractor, Learning Activity Packages 90-94; Painting the Tractor, Learning Activity Packages 95-96.

    Clemson Univ., SC. Vocational Education Media Center.

    This series of learning activity packages focuses on three areas of tractor mechanics: (1) maintaining and servicing the engine, (2) lubricating the tractor, and (3) painting the tractor. Each of the nineteen illustrated learning activity packages follows a typical format: introduction, directions, objectives, learning activities, tools and…

  13. Activation analysis as applied to environmental substances

    The historical background of activation analysis as applied to environmental problems is first briefly described. Then, the present state of its utilization for environmental samples, mainly atmospheric floating particles and human hairs, is reviewed. The problem with irradiation reactors is also mentioned. In the activation analysis of environmental substances, the instrumental neutron activation analysis (INAA) with the thermal neutrons in reactors is the main; besides, there are the methods with bremsstrahlung, etc. The INAA is most effectively used for atmospheric airborne particles and the micro-elements in human hairs. In Japan, the INAA is currently employed by the Environmental Agency in its national air pollution surveillance network for metallic pollutants. The problem with reactors is the limited capacity for thermal neutron irradiation. (Mori, K.)

  14. New lubricating material for hydraulic turbine equipment

    The release of lubricant into the water stream after passage through hydraulic turbines is an environmental issue of concern. To address concerns about the self-lubricating bearing materials being used to replace the standard grease lubricated bronze bearings for wicket gates, a survey was carried out to determine the availability and use of self-lubricating bearing materials. Included in the survey were users, bearing suppliers and turbine manufacturers. Information derived from the survey included extent of use, historical data, bearing design parameters, lubrication practices, maintenance activity, and environmental issues. Results of the survey are tabulated. It was found that the use of self-lubricating bearing materials is the predominant technology available to satisfy environmental concerns for hydraulic equipment. A number of materials are available based on both metallic and polymer materials. A numer of materials are available that have demonstrated satisfactory service life for at least 10 years. As an alternative, hydraulic equipment can be lubricated with an environmentally friendly lubricant, although there are none commercially available that are biodegradable and non-toxic. In new equipment the cost of using self-lubricating bearings could be less than grease lubricated bronze bearings with automatic lubrication system. 3 refs., 4 figs., 3 tabs

  15. Controller modification applied for active fault detection

    Niemann, Hans Henrik; Stoustrup, Jakob; Poulsen, Niels Kjølstad

    2014-01-01

    This paper is focusing on active fault detection (AFD) for parametric faults in closed-loop systems. This auxiliary input applied for the fault detection will also disturb the external output and consequently reduce the performance of the controller. Therefore, only small auxiliary inputs are used...... modify the feedback controller with a minor effect on the external output in the fault free case. Further, in the faulty case, the signature of the auxiliary input can be optimized. This is obtained by using a band-pass filter for the YJBK parameter that is only effective in a small frequency range where...... the frequency for the auxiliary input is selected. This gives that it is possible to apply an auxiliary input with a reduced amplitude. An example is included to show the results....

  16. Lubricant composition

    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 380C. (1000F.) 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

  17. Limits of Lubrication in

    Olsson, David Dam

    Strategic stainless steel surfaces have been developed and investigated during the project in close cooperation with the Department of Chemistry, DTU with the purpose of enhancing the tribological properties. This has been achieved successfully by applying electrochemical treatments of normal as...... delivered stainless steel surfaces implying microstructure changes in terms of larger ratio of closed lubricant pockets due to selective grain boundary etching. Strategic surfaces have also been created by macroscopic texturing using spherical indentations having a very small edge slope in order to promote...... using plain mineral oil is possible without any lubricant breakdown. In deep drawing, 2mm stainless steel blanks can be drawn to drawing ratio of DR=2.0 over a die entry radius of rd=3mm again using a plain mineral oil containing no additives. In stretch forming, friction is reduced considerably by...

  18. Investigation of the Wheel-Flange Lubrication of Railway Trains

    A tracer method was applied to investigate the wheel-flange lubrication action of the new Austrian multiple-unit train ''Transalpin''. On electric engines the flanges of the first pair of wheels are lubricated by a pendulum oil pump. This pump starts to work when there is lateral movement of the engine in curves or at high speed on straight lines. The lubricating oil is transferred, while the train is underway, from the first wheel to the inner surface of the rail. From there it should be taken up by the following wheels of the train. In this way the friction between the rails and the wheel flanges can be reduced and as a consequence the wear of material is decreased. Until the present investigation it has not been possible to get quantitative information about the action of this type of lubrication. By adding the tracer 198Au in the form of a colloid to the lubricating oil (specific activity 0.5 Ci/litre), quantitative measurements of the oil transport mechanism could be made on the moving train. The detection of the labelled lubricant was possible even on the last wheels of a train of 44 axles. The oil films which were still detectable on the wheel flanges had a thickness of about 0. 3 microns. By this tracer method, the dependence of lubrication on the speed and the line conditions can also be determined. The tracer method has a wide range of applications in the study of underway conditions in railroad operation including the investigation of the sine movement of trains. (author)

  19. Experimental study and modelling of mixed particulate lubrication with MoS2 powder solid lubricant

    H. Wiśniewska-Weinert

    2011-12-01

    Full Text Available Purpose: The purpose of the paper is experimental study and modelling of mixed particulate lubrication with MoS2 powder solid lubricant.Design/methodology/approach: In the present investigation, ball-on-disc experiments were carried out to determine the lubrication performance of MoS2 solid lubricant powder that could be used for hard PVD coatings applied for forging and stamping tools.Findings: The proposed solid lubricant nano- and submicroparticles mixture demonstrates excellent potential for use in mixed lubrication regimes The quasi-hydrodynamic behaviour of solid lubricant and wear debris particles results in low friction coefficients of hard coating – steel ball friction pairs.Research limitations/implications: The solid lubricant particle exfoliation and formation of tribofilms on micro-asperities allow to achieve the boundary lubrication effects which is found to more preferable for steel contacts rather than for hard coatings.Originality/value: The model of mixed lubrication based on non Newtonian behaviour of powder solid lubricant was validated based on the experimental results. Results of calculation of Stribeck curves demonstrate the potential of modelling of friction process by sharing boundary and quasi-hydrodynamic processes.

  20. Impact of Lubricant Additives on thePhysicochemical Properties and Activity of Three‐Way Catalysts

    Chao Xie

    2016-04-01

    Full Text Available As alternative lubricant anti‐wear additives are sought to reduce friction and improve overall fuel economy, it is important that these additives are also compatible with current emissions control catalysts. In the present work, an oil‐miscible phosphorous‐containing ionic liquid (IL, trihexyltetradecylphosphonium bis(2‐ethylhexyl phosphate ([P66614][DEHP], is evaluated for its impact on three‐way catalysts (TWC and benchmarked against the industry standard zinc‐dialkyl‐dithio‐phosphate (ZDDP. The TWCs are aged in different scenarios: neat gasoline (no‐additive, or NA, gasoline+ZDDP, and gasoline+IL. The aged samples, along with the as‐received TWC, are characterized through various analytical techniques including catalyst reactivity evaluation in a bench‐flow reactor. The temperatures of 50% conversion (T50 for the ZDDP‐aged TWCs increased by 30, 24, and 25 °C for NO, CO, and C3H6, respectively, compared to the no‐additive case. Although the IL‐aged TWC also increased in T50 for CO and C3H6, it was notably less than ZDDP, 7 and 9 °C, respectively. Additionally, the IL‐aged samples had higher water‐gas‐shift reactivity and oxygen storage capacity than the ZDDP‐aged TWC. Characterization of the aged samples indicated the predominant presence of CePO4 in the ZDDP‐aged TWC aged by ZDDP, while its formation was retarded in the case of IL where higher levels of AlPO4 is observed. Thus, results in this work indicate that the phosphonium‐phosphate IL potentially has less adverse impact on TWC than ZDDP.

  1. Estimation of appropriate lubricating film thickness in ceramic-on-ceramic hip prostheses

    Tauviqirrahman, M.; Muchammad, Bayuseno, A. P.; Ismail, R.; Saputra, E.; Jamari, J.

    2016-04-01

    Artificial hip prostheses, consisting of femoral head and acetabular cup are widely used and have affected the lives of many people.However, the primary issue associated with the long term performance of hip prostheses is loosening induced by excessive wear during daily activity. Therefore, an effective lubrication is necessary to significantly decrease the wear. To help understand the lubricating performance of such typical hip joint prostheses, in the present paper a hydrodynamic lubrication model based on Reynolds equationwas introduced. The material pairs of ceramic acetabular cup against ceramic femoral head was investegated.The main aim of this study is to investigate of the effect of loading on the formation of lubricating film thickness.The model of a ball-in-socket configuration was considered assuming that the cup was stationary while the ball was to rotate at a steady angular velocityvarying loads.Based on simulation result, it was found that to promote fluid film lubrication and prevent the contacting components leading to wear, the film thickness of lubricant should be determined carefully based on the load applied. This finding may have useful implication in predicting the failure of lubricating synovial fluid film and wear generation in hip prostheses.

  2. Epithermal neutron activation analysis in applied microbiology

    Some results from applying epithermal neutron activation analysis at FLNP JINR, Dubna, Russia, in medical biotechnology, environmental biotechnology and industrial biotechnology are reviewed. In the biomedical experiments biomass from the blue-green alga Spirulina platensis (S. platensis) has been used as a matrix for the development of pharmaceutical substances containing such essential trace elements as selenium, chromium and iodine. The feasibility of target-oriented introduction of these elements into S. platensis biocomplexes retaining its protein composition and natural beneficial properties was shown. The absorption of mercury on growth dynamics of S. platensis and other bacterial strains was observed. Detoxification of Cr and Hg by Arthrobacter globiformis 151B was demonstrated. Microbial synthesis of technologically important silver nanoparticles by the novel actinomycete strain Streptomyces glaucus 71 MD and blue-green alga S. platensis were characterized by a combined use of transmission electron microscopy, scanning electron microscopy and energy-dispersive analysis of X-rays. It was established that the tested actinomycete S. glaucus 71 MD produces silver nanoparticles extracellularly when acted upon by the silver nitrate solution, which offers a great advantage over an intracellular process of synthesis from the point of view of applications. The synthesis of silver nanoparticles by S. platensis proceeded differently under the short-term and long-term silver action. (author)

  3. Elasto-hydrodynamic lubrication

    Dowson, D; Hopkins, D W

    1977-01-01

    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

  4. Lubricants in Pharmaceutical Solid Dosage Forms

    Jinjiang Li

    2014-02-01

    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.

  5. Applied nuclear physics group - activities report. 1977-1997

    This report presents the activities conducted by the Applied Nuclear Physics group of the Londrina State University - Applied Nuclear Physics Laboratory - Brazil, from the activities beginning (1977) up to the end of the year 1997

  6. Control System Design for Active Lubrication with Theoretical and Experimental Examples

    Santos, Ilmar; Scalabrin, A.

    2003-01-01

    This work focuses on the theoretical and experimental behavior of rigid rotors controlled by tilting-pad journal bearings with active oil injection. Initially the mathematical model of the active bearing is presented: The equations that describe the dynamics of hydraulic actuators are introduced...... the control system of the active bearing based on root locus curves. The active system stability is analyzed by calculating its eigenvalues and frequency response curves. The theoretical and experimental results show that this kind of bearing can significantly reduce the vibration level of rotating...

  7. Research on Mobile Learning Activities Applying Tablets

    Kurilovas, Eugenijus; Juskeviciene, Anita; Bireniene, Virginija

    2015-01-01

    The paper aims to present current research on mobile learning activities in Lithuania while implementing flagship EU-funded CCL project on application of tablet computers in education. In the paper, the quality of modern mobile learning activities based on learning personalisation, problem solving, collaboration, and flipped class methods is…

  8. Dynamic Coefficients of a Tilting Pad With Active Lubrication: Comparison Between Theoretical and Experimental Results

    Cerda Varela, Alejandro Javier; Santos, Ilmar

    2015-01-01

    This paper deals with the validation of the mathematical model for predicting the equivalent stiffness and damping of an active tilting-pad bearing. The active bearing design includes an injection nozzle in the pad and a hydraulic supply system featuring a servovalve, which enables to modify...

  9. Solid Lubricant For Alumina

    Dellacorte, Christopher; Pepper, Stephen V.; Honecy, Frank S.

    1993-01-01

    Outer layer of silver lubricates, while intermediate layer of titanium ensures adhesion. Lubricating outer films of silver deposited on thin intermediate films of titanium on alumina substrates found to reduce sliding friction and wear. Films provide effective lubrication for ceramic seals, bearings, and other hot sliding components in advanced high-temperature engines.

  10. Interdisciplinary strate in applied performance and activism

    Johansson, Ola

    2014-01-01

    The paper addresses the challenges and advantages of collaborative stratification in the continuum of theatre and fine arts, with examples from applied performance projects in international contexts. With different approaches to performance/media, acting/agency, devising/curatorship and participation/social engagement, collaborative processes have proved to be quite incongruent in method and motif, although inclusive and versatile in media tactics and political outreach. In post-Brechtian the...

  11. Lubrication in Hot Tube Extrusion of Superalloys and Ti Alloys

    2001-01-01

    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.

  12. Ultrasonic monitoring of lubricating conditions of hydrodynamic bearing

    The performance of a hydrodynamic bearing is illustrated by the lubricating conditions which transfer from ones to another when working condition is changed. The thickness of lubricant film is the key parameter of lubricating conditions. The lubricating conditions of hydrodynamic bearing can be monitored by the measured film thickness and the relationship between them. For thin lubricant film layers less than ultrasonic wavelength, the spring model method is applied to measure the film thickness. The proportion of the ultrasound reflected from film layer, depended on the film stiffness, is determined and then can be readily converted to the film thickness. For the thicker films ranging from several microns to tens microns, ultrasonic resonance method was employed. An adaptive measurement algorithm is presented to automatically choice appropriate ultrasonic measurement method according to the different lubricating stage. All the range of lubricant film thickness of a hydrodynamic bearing can then be measured by the automatic selection of spring model and resonance methods. Simulation device of lubricant film layers with PZT positioning stage is designed to verify the accuracy of the adaptive measurement algorithm. Hydrodynamic bearing experimental setup is used to generate varies of lubricating condition by changing the shaft speed, radial direction loading force, and lubricant temperature. The lubricating condition of hydrodynamic bearing is then evaluated according to the measured lubricant film thickness and the working conditions.

  13. Active Lubrication for Reducing Wear and Vibration: A combination of Fluid Power Control and Tribology

    Nicoletti, Rodrigo; Santos, Ilmar

    2002-01-01

    The use of fluid power to reduce and control rotor vibration in rotating machines is investigated. An active hybrid bearing is studied, whose main objective is to reduce wear and vibration between rotating and stationary machinery parts. By injecting pressurised oil into the oil film, through...

  14. From Hybrid to Actively-Controlled Gas Lubricated Bearings – Theory and Experiment

    Morosi, Stefano

    bearings, tilting pad and flexure pivot gas bearings. These solutions proved to be effective in improving static and dynamic properties of the bearings, however issues related to the manufacturing and accuracy of predictions has so far limited their applications. Another drawback is that passive bearings...... determined by the appearance of subsynchronous whirl instability. In fact, postponing the onset speed of instability poses one of the greatest challenges in high-speed gas bearing design. A great deal of research is devoted to attack such issues, where most propose passive designs such as compliant foil...... offer a low degree of robustness, meaning that an accurate optimization is necessary for each application. Another way of improving gas bearings operation performance is by using active control systems, transforming conventional gas bearings in an electro-mechanical machine component. In this framework...

  15. Neutron activation analysis applied to archaeological problems

    Among the various techniques, the main analytical methods used to characterize ceramics are undoubtedly XRF and INAA. The principles of NAA differ from those of XRF in that samples are irradiated by thermal neutrons from a nuclear reactor. During irradiation, a few neutrons are captured by the nuclei of atoms in the specimen. This process, called activation, causes some of the nuclei to become unstable. During and after neutron irradiation, these unstable nuclei emit γ rays with unique energies at rates defined by the characteristic half-lives of the radioactive nuclei. Identification of the radioactive nucleus is possible by measuring the γ ray energies. Determination of their intensities permits quantitative analysis of the elements in the sample. The use of NAA in ceramics by a combination of two or three irradiation, decay and measurement strategies allows the determination of the elements Ba, Ce, Cl, Co, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, U, Yb, Zn and Zr, if necessary by changing the irradiation, decay and measurement schemes. In general, XRF is more available, more rapid and less expensive than NAA. However, NAA offers a far greater number of elements, more sensitivity, superior precision and greater accuracy than XRF. On the other hand, NAA can be performed on extremely small samples (5-10 mg), meaning that only minor damage to valuable artefacts may be required

  16. The determination of trace elements in new and used lubricating oils by neutron activation analysis

    The trace elements on unused and used motor oils of different brands utilized in different light, medium and heavy weight vehicles by neutron activation analysis(N A A) has been measured. To find out the exact amount of trace elements in used motor oil only due to erosion was investigated both qualitatively and quantitatively through neutron activation analysis by thermal neutrons and X ray fluorescence analysis. Forty sample of motor oil with natural basis and ten samples with synthetic basis, plus thirteen samples as filters, gas and oil rings, fix and moving bearing has been provided. For determining the quality of elements in the given samples the time of radiation for short lived elements was from one minute to ten minutes in 1 MW reactor power, using pneumatic rabbit system. The elements Al, V, Ca, and specially S have been recognized. For long lived elements the irradiation time was one hour, one and a half hour and 2 hours. As a whole, for all samples 250 time radiations have been determined. Counting of samples have been done by multichannel analyzers connected to computer P D P/11 and IBM/P C at different times from 200 seconds to 4000 seconds. The time interval between the end of irradiation till start of counting, was from three minutes to a year. Analysis of samples have been provided by software O R A C L in computer P D P/11 and software M A S T E R O in computer IBM/P C. As a whole, nine hundred spectra and analysis have been provide. Thirty one elements have been identified. They are as follows. Al, V, S, Cu, Ca, Mg, Cl, In, Mn, K, Na, As, Br, Cd, Cr, Fe, Sb, Sc, Zn, Ag, Co, Ni, Au, Cs, Eu, Sm, Lu, La, W, Xe, Ba, Hf. These elements were found in all samples. But elements La, Lu, Au, Cs, Ni, Eu, Xe, W, Ba, and Hf were found in some samples. By comparing methods with standards and using thermal neutron flux, the quantitative amounts of elements were found. By using X-ray fluorescence Zn was found in some samples and in some others (used oil) Zn, Br

  17. CALCIUM SOAP LUBRICANTS

    Alaz, Izer; Tugce, Nefise; Devrim, Balköse

    2014-01-01

    The article studies the properties of calcium stearate (CaSt2) and lubricants produced on its basis. These lubricants were prepared using sodium stearate and calcium chloride by subsidence from aqueous solutions. The CaSt2 and the light fraction of crude oil were mixed together to obtain lubricating substances. The article shows that CaSt2 had the melting temperature of 142.8 C that is higher than the melting temperature of crude oil (128 C). The compositions of obtained lubricants were stu...

  18. Grease lubrication in rolling bearings

    Lugt, Piet M

    2012-01-01

    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

  19. Metal forming and lubrication

    Bay, Niels

    2000-01-01

    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...

  20. Applied research of environmental monitoring using instrumental neutron activation analysis

    Chung, Young Sam; Moon, Jong Hwa; Chung, Young Ju

    1997-08-01

    This technical report is written as a guide book for applied research of environmental monitoring using Instrumental Neutron Activation Analysis. The contents are as followings; sampling and sample preparation as a airborne particulate matter, analytical methodologies, data evaluation and interpretation, basic statistical methods of data analysis applied in environmental pollution studies. (author). 23 refs., 7 tabs., 9 figs.

  1. Dairy Equipment Lubrication

    1978-01-01

    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.

  2. PRODUCTION OF HIGH QUALITY LUBRICATING BASE OIL

    2001-01-01

    @@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.

  3. Radial oil injection applied to main engine bearings: evaluation of injection control rules

    Estupiñan, EA; Santos, Ilmar

    2012-01-01

    The performance of main bearings in a combustion engine affects key functions such as durability, noise and vibration. Thus, with the aim of reducing friction losses and vibrations between the crankshaft and the bearings, the work reported here evaluates different strategies for applying controll...... actively lubricated bearing is compared with the performance of the conventional lubricated bearing, giving some insights into the minimum fluid film thickness, maximum fluid film pressure, friction losses and maximum vibration levels....... controllable radial oil injection to main crankshaft journal bearings. In an actively lubricated bearing, conventional hydrodynamic lubrication is combined with controllable hydrostatic lubrication, where the oil injection pressures can be modified depending on the operational conditions. In this study, the...

  4. Nanorheometry of Molecularly Thin Liquid Lubricant Films Coated on Magnetic Disks

    Shintaro Itoh; Yuya Hamamoto; Koki Ishii; Kenji Fukuzawa; Hedong Zhang

    2012-01-01

    Molecularly thin lubricant films are used for the lubrication of head disk interfaces in hard disk drives. The film thickness is reduced to 1-2 nm to minimize the magnetic spacing, and optimal, precise design is required to obtain sufficient lubrication. However, until now, there was no generally applicable method for investigating such thin films. Therefore, we developed a highly sensitive shear force measuring method and have applied it to the viscoelastic measurement of lubricant films coa...

  5. Lubricating graphene with a nanometer-thick perfluoropolyether

    Due to its atomic thickness (thinness), the wear of graphene in nanoscale devices or as a protective coating is a serious concern. It is highly desirable to develop effective methods to reduce the wear of graphene. In the current paper, the effect of a nano-lubricant, perfluoropolyether, on the wear of graphene on different substrates is investigated. Graphene was synthesized by chemical vapor deposition (CVD) and characterized by Raman spectroscopy. The nano-lubricant is applied on the graphene by dip-coating. The friction and wear of graphene samples are characterized by nanotribometer, AFM, optical microscopy and Raman spectroscopy. The results showed that lubricating silicon/graphene with nano-lubricant reduces the friction but increases the wear. However, lubricating nickel/graphene with nano-lubricant has little effect on the friction but reduce the wear significantly. The underlying mechanism has been discussed on the basis of the graphene–substrate adhesion and the roughness. The current study provides guidance to the future design of graphene-containing devices. - Highlights: • The effect of a nano-lubricant on the friction and wear of CVD graphene was studied. • Lubricating Graphene/Si results in lower friction but higher wear. • Lubricating Ggraphene/Ni results in lower wear but unchanged friction. • The mechanisms were discussed based on the roughness and interfacial adhesion

  6. Lubricating graphene with a nanometer-thick perfluoropolyether

    Kozbial, Andrew [Department of Chemical and Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Li, Zhiting [Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Iasella, Steven; Taylor, Alexander T.; Morganstein, Brittni; Wang, Yongjin [Department of Chemical and Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Sun, Jianing [J.A. Woollam Co., Inc., 645 M Street, Suite 102, Lincoln, NE 68508 (United States); Zhou, Bo; Randall, Nicholas X. [CSM Instruments, 197 1st Avenue, Needham, MA 02494 (United States); Liu, Haitao, E-mail: hliu@pitt.edu [Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Li, Lei, E-mail: lel55@pitt.edu [Department of Chemical and Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Department of Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States)

    2013-12-31

    Due to its atomic thickness (thinness), the wear of graphene in nanoscale devices or as a protective coating is a serious concern. It is highly desirable to develop effective methods to reduce the wear of graphene. In the current paper, the effect of a nano-lubricant, perfluoropolyether, on the wear of graphene on different substrates is investigated. Graphene was synthesized by chemical vapor deposition (CVD) and characterized by Raman spectroscopy. The nano-lubricant is applied on the graphene by dip-coating. The friction and wear of graphene samples are characterized by nanotribometer, AFM, optical microscopy and Raman spectroscopy. The results showed that lubricating silicon/graphene with nano-lubricant reduces the friction but increases the wear. However, lubricating nickel/graphene with nano-lubricant has little effect on the friction but reduce the wear significantly. The underlying mechanism has been discussed on the basis of the graphene–substrate adhesion and the roughness. The current study provides guidance to the future design of graphene-containing devices. - Highlights: • The effect of a nano-lubricant on the friction and wear of CVD graphene was studied. • Lubricating Graphene/Si results in lower friction but higher wear. • Lubricating Ggraphene/Ni results in lower wear but unchanged friction. • The mechanisms were discussed based on the roughness and interfacial adhesion.

  7. 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.

  8. Importance of lubricant analysis

    Sreten R. Perić

    2012-04-01

    Full Text Available Monitoring the performance of lubricants in practical application has multiple significance for both the consumer and the lubricant manufacturer. The primary significance for the consumer is extended life and timely change of lubricants, which keeps the costs of maintenance down. The lubricant manufacturer gains by creating a partner relationship with the consumer, as well as creating the possibility of gathering information about the performance of his product which will serve as the foundation for its further improvement and development. If we wish to maintain technical systems so that they have minimum halts and costs caused by halt removal or system failures, we must monitor data indicating equipment condition throughout the system operation. It is especially difficult to obtain data on equipment condition for parts which cannot be observed due to their position. In such cases, the oil analysis enables a continuous equipment condition monitoring and timely response in order to prevent undesirable prolonged halts.

  9. 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...

  10. The use of radioactive tracers in lubrication and wear research

    In many lubrication and wear problems, processes occurring on a very small scale have to be studied and the great sensitivity of radioactive tracer methods has been successfully applied. Several examples of such applications are cited from the work of the Lubrication and Wear Division of the National Engineering Laboratory in the United Kingdom. The quantitative relation between metal transfer and boundary friction is studied as a function of sliding velocity, surface roughness and the presence of lubricants. In order to study the distribution of wear, cast iron plugs containing Ir192 are inserted in the liners of a Diesel engine and the radioactivity present in oil samples is measured. Radioactive iron and iron oxide particles are used to study then role in the wear process. The reactivity of strained metal surface is studied with the aid of C14- labelled stearic acid and of S35 in solution. The reaction rates of gear oil additive are being studied by passing short electric-current pulses through metal wires immersed in solutions of compounds labelled with S35 and P32. The build-up of anti-wear films on the surface of gear teeth is being studied as a function of lead, speed and running time. A problem encountered in many of these applications is the conversion of the measured activity into absolute quantities of materials present in surface films or in wear debris. Calibration methods have been developed for this purpose. (author)

  11. Applying Activity Based Costing In Tourism Services In Uzbekistan

    Alisher Eshtaev

    2011-01-01

    The paper studied opportunities of applying activity based costing and management (ABCM) at tourism firms in Uzbekistan. The present accounting practice is analyzed and critically studied, the scientific research done to show the advantages and disadvantages of using present methods of accounting, and need to implementation of more responsive and innovative financial settings in today’s dynamic business environment is proven. The methods of Cooper’s 2-stage implementation, Activity-Product-De...

  12. Finite element models applied in active structural acoustic control

    Oude Nijhuis, Marco H.H.; Boer, de André; Rao, Vittal S.

    2002-01-01

    This paper discusses the modeling of systems for active structural acoustic control. The finite element method is applied to model structures including the dynamics of piezoelectric sensors and actuators. A model reduction technique is presented to make the finite element model suitable for controll

  13. Modeling Protein Folding and Applying It to a Relevant Activity

    Nelson, Allan; Goetze, Jim

    2004-01-01

    The different levels of protein structure that can be easily understood by creating a model that simulates protein folding, which can then be evaluated by applying it to a relevant activity, is presented. The materials required and the procedure for constructing a protein folding model are mentioned.

  14. Power system with an integrated lubrication circuit

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

    2009-11-10

    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.

  15. 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...

  16. Sputtering technology in solid film lubrication

    Spalvins, T.

    1978-01-01

    Potential and present sputtering technology is discussed as it applies to the deposition of solid film lubricants particularly MoS2, WS2, and PTFE. Since the sputtered films are very thin, the selection of the sputtering parameters and substrate condition is very critical as reflected by the lubricating properties. It was shown with sputtered MoS2 films that the lubricating characteristics are directly affected by the selected sputtering parameters (power density, pressure, sputter etching, dc-biasing, etc.) and the substrate temperature, chemistry, topography and the environmental conditions during the friction tests. Electron microscopy and other surface sensitive analytical techniques illustrate the resulting changes in sputtered MoS2 film morphology and chemistry which directly influence the film adherence and frictional properties.

  17. Role of water lubricated bearings in Candu reactors

    During the twentieth century a great emphasis was placed in understanding and defining the operating regime of oil and grease lubricated components. Major advances have been made through elastohydrodynamic lubrication theory in the quantifying the design life of heavily loaded components such as rolling element bearings and gears. Detailed guidelines for the design of oil and grease lubricated components are widely available and are being applied to the successful design of these components. However similar guidelines for water lubricated components are either not available or not well documented. It is often forgotten that the water was used as a lubricant in several components as far back as 1884 B.C. During the twentieth century the water lubricated components continued to play a major role in some high technology industries such as in the power generation plants. In CANDU nuclear reactors water lubrication of several critical components always occupied a pride place and in most cases the only practical mode of lubrication of several critical components always occupied a pride place and in most cases the only practical mode of lubrication. This paper presents some examples of the major water lubricated components in a CANDU reactors. Major part of the paper is focused on presenting an example of successful operating history of water lubricated bearings used in the HT pumps are presented. Both types of bearings have been qualified by tests for operation under normal as well as under more severe postulated condition of loss-of-coolant-accident (LOCA). These bearings have been designed to operate for the 30 years in the existing CANDU 6 (600 MW) reactors. However for the next generation of CANDU 6 reactors which go into service in the year 2003, the HT pump bearing life has been extended to 40 years. (author)

  18. Creation of solid lubricant firms by nanostructure control

    The friction coefficient can be decreased by increasing the hardness of a sliding plane while maintaining low shear resistance parallel to its substrate using nanostructural control techniques. Herein, nanoperiodic multilayer films composed of solid lubricant materials were proposed to develop a new solid lubricant film having lower friction than that of conventional solid lubricant films. The applied solid lubricant materials were soft metals including Au and Ag, polymers such as PTFE (polytetrafluoroethylene), and crystallizing layered inorganic compounds such as MoS2 (molybdenum disulfide), WS2 (tungsten disulfide), graphite, and hexagonal-BN. The nanoindentation properties of the obtained films were evaluated. Multilayered films with a suitable period showed a high hardness and elastic modulus. These nanoperiod multilayer solid lubricant films exhibited lower friction, higher nanowear resistance, and superior friction endurance than those of monolayer films. (author)

  19. Finite element models applied in active structural acoustic control

    Oude Nijhuis, Marco H.H.; de Boer; Rao, Vittal S.

    2002-01-01

    This paper discusses the modeling of systems for active structural acoustic control. The finite element method is applied to model structures including the dynamics of piezoelectric sensors and actuators. A model reduction technique is presented to make the finite element model suitable for controller design. The reduced structural model is combined with an acoustic model which uses the radiation mode concept. For a test case consisting of a rectangular plate with one piezo patch the model re...

  20. Applying Activity Based Costing In Tourism Services In Uzbekistan

    Alisher Eshtaev

    2011-04-01

    Full Text Available The paper studied opportunities of applying activity based costing and management (ABCM at tourism firms in Uzbekistan. The present accounting practice is analyzed and critically studied, the scientific research done to show the advantages and disadvantages of using present methods of accounting, and need to implementation of more responsive and innovative financial settings in today’s dynamic business environment is proven. The methods of Cooper’s 2-stage implementation, Activity-Product-Dependence matrix by Roztocki  were used for Planet Tour Co. ABCM is recommended as accurate cost management of products or services in tourism firms in Uzbekistan.

  1. Ion-exchange resin separation applied to activation analysis (1963)

    The separation techniques based on ion-exchange resins have been used, in this study, for carrying out activation analyses on about thirty impurities. A separation process has been developed so as to standardise these analyses and to render them execution a matter of routine. The reparation yields obtained are excellent and make it possible to carry out analyses on samples having a large activation cross-section ween working inside a reinforced fume-cupboard. This technique has been applied to the analysis of impurities in tantalum, iron, gallium, germanium, terphenyl, and tungsten. The extension of this process to other impurities and to other matrices is now being studied. (authors)

  2. Temperature dependence on the synthesis of Jatropha bio lubricant

    Full text: Jatropha oil has good potential as the renewable energy as well as lubricant feedstock. The synthesis of jatropha bio lubricant was performed by transesterification of jatropha methyl ester (JME) with trimethyl-ol-propane (TMP) with sodium methoxide (NaOCH3) catalyst. The effects of temperature on the synthesis were studied at a range between 120 degree Celsius and 200 degree Celsius with pressure kept at 10 mbar. The conversion of JME to jatropha bio lubricant was found to be the highest (47 %) at 200 degree Celsius. However, it was suggested that the optimum temperature of the reaction is at 150 degree Celsius due to insignificant improvement in bio lubricant production. To maintain forward reaction, the excess amount of JME was maintained at 3.9:1 ratios to TMP. Kinetic study was done and compared. The synthesis was found to follow a second order reaction with overall rate constant of 1.49 x 10-1 (% wt/ wt.min.degree Celsius)-1. The estimated activation energy was 3.94 kJ/mol. Pour point for jatropha bio lubricant was at -3 degree Celsius and Viscosity Index (VI) ranged from 178 to 183. The basic properties of jatropha bio lubricant, pour point and viscosities are found comparable to other plant based bio lubricant, namely palm oil and soybean based bio lubricant. (author)

  3. Mixed lubricated line contacts

    Faraon, Irinel Cosmin

    2005-01-01

    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 ess

  4. Glass microsphere lubrication

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

    1991-01-01

    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

  5. Swimming and other activities: applied aspects of fish swimming performance

    Castro-Santos, Theodore R.

    2011-01-01

    Human activities such as hydropower development, water withdrawals, and commercial fisheries often put fish species at risk. Engineered solutions designed to protect species or their life stages are frequently based on assumptions about swimming performance and behaviors. In many cases, however, the appropriate data to support these designs are either unavailable or misapplied. This article provides an overview of the state of knowledge of fish swimming performance – where the data come from and how they are applied – identifying both gaps in knowledge and common errors in application, with guidance on how to avoid repeating mistakes, as well as suggestions for further study.

  6. Neutron activation: an invaluable technique for teaching applied radiation

    This experiment introduces students to the important method of neutron activation. A sample of aluminium was irradiated with neutrons from an isotropic 241Am-Be source. Using γ-ray spectroscopy, two radionuclide products were identified as 27Mg and 28Al. Applying a cadmium cut-off filter and an optimum irradiation time of 45 min, the half-life of 27Mg was determined as 9.46±0.50 min. The half-life of the 28Al radionuclide was determined as 2.28±0.10 min using a polythene moderator and an optimum irradiation time of 10 min. (author)

  7. Studies on micro plasto hydrodymic lubrication in metal forming

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

    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,......, friction and pocket geometry and establishing a mathematical model predicting the onset of lubricant escape. The present paper presents an overview of these studies on MPHDL in metal forming carried out at the Technical University of Denmark....

  8. Applied research and development of neutron activation analysis

    Chung, Yong Sam; Moon, Jong Hwa; Kim, Sun Ha; Baek, Sung Ryel; Kim, Young Gi; Jung, Hwan Sung; Park, Kwang Won; Kang, Sang Hun; Lim, Jong Myoung

    2003-05-01

    The aims of this project are to establish the quality control system of Neutron Activation Analysis(NAA) due to increase of industrial needs for standard analytical method and to prepare and identify the standard operation procedure of NAA through practical testing for different analytical items. R and D implementations of analytical quality system using neutron irradiation facility and gamma-ray measurement system and automation of NAA facility in HANARO research reactor are as following ; 1) Establishment of NAA quality control system for the maintenance of best measurement capability and the promotion of utilization of HANARO research reactor 2) Improvement of analytical sensitivity for industrial applied technologies and establishment of certified standard procedures 3) Standardization and development of Prompt Gamma-ray Activation Analysis (PGAA) technology.

  9. Applied research and development of neutron activation analysis

    The aims of this project are to establish the quality control system of Neutron Activation Analysis(NAA) due to increase of industrial needs for standard analytical method and to prepare and identify the standard operation procedure of NAA through practical testing for different analytical items. R and D implementations of analytical quality system using neutron irradiation facility and gamma-ray measurement system and automation of NAA facility in HANARO research reactor are as following ; 1) Establishment of NAA quality control system for the maintenance of best measurement capability and the promotion of utilization of HANARO research reactor 2) Improvement of analytical sensitivity for industrial applied technologies and establishment of certified standard procedures 3) Standardization and development of Prompt Gamma-ray Activation Analysis (PGAA) technology

  10. Selection of lubricant material for the roller chains of the AHM grapple drive system for the CRBRP

    Properties of Anderol 732 lubricating grease are evaluated to meet the design requirements for the Clinch River Breeder Reactor Plant (CRBRP) auxiliary handling machine (AHM) chain lubrication. Based on the evaluation made in this report, the material is recommended as a lubricant for the specified application. The material is to be applied by the chain manufacturer prior to installation in the AHM. 1 tab

  11. Carbon-based tribofilms from lubricating oils.

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

    2016-08-01

    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. PMID:27488799

  12. Database mining applied to central nervous system (CNS) activity.

    Pintore, M; Taboureau, O; Ros, F; Chrétien, J R

    2001-04-01

    A data set of 389 compounds, active in the central nervous system (CNS) and divided into eight classes according to the receptor type, was extracted from the RBI database and analyzed by Self-Organizing Maps (SOM), also known as Kohonen Artificial Neural Networks. This method gives a 2D representation of the distribution of the compounds in the hyperspace derived from their molecular descriptors. As SOM belongs to the category of unsupervised techniques, it has to be combined with another method in order to generate classification models with predictive ability. The fuzzy clustering (FC) approach seems to be particularly suitable to delineate clusters in a rational way from SOM and to get an automatic objective map interpretation. Maps derived by SOM showed specific regions associated with a unique receptor type and zones in which two or more activity classes are nested. Then, the modeling ability of the proposed SOM/FC Hybrid System tools applied simultaneously to eight activity classes was validated after dividing the 389 compounds into a training set and a test set, including 259 and 130 molecules, respectively. The proper experimental activity class, among the eight possible ones, was predicted simultaneously and correctly for 81% of the test set compounds. PMID:11461760

  13. Activities report 1977--78. Applied mathematics department 5640

    This report is a compilation of independent articles highlighting some of the work done in the Applied Mathematics Department during the years 1977 and 1978. It is neither an exhaustive report on all activities in the department during this period nor a list of the most substantial mathematical contributions. Instead, it is a selection of topics which are thought to be of greatest interest because of their importance to Sandia. The report is divided into four principal sections which reflect the department's major areas of interest: Mathematical Physics, Computational Mathematics, Probability and Statistics, and Discrete Mathematics. To provide a smoother narrative, references are omitted from the text. However, a complete department bibliography of corporate and open publications as well as technical presentations for the period October 1977 through December 1978 is appended. 4 figures, 3 tables

  14. Multiresolution active contour model applied on lung and colon images

    Dehmeshki, Jamshid; Siddique, Musib; Wong, Wing; Chis Ster, Irina

    2004-05-01

    This paper deploys a wavelet based scale-space approach to extract the boundary of the object of interest in medical CT images. The classical approach of the active contour models consists of starting with an initial contour, to deform it under the action of some forces attracting the contour towards the edges by means of a set of forces. The mathematical model involves in the minimisation of an objective function called energy functional, which depends on the geometry of the contour as well as of the image characteristics. Various strategies could be used for the formulation of the energy functional and its optimisation. In this study, a wavelet based scale-space approach has been adopted. The coarsest scale is able to enlarge the capture region surrounding an object and avoids the trapping of contour into weak edges. The finer scales are used to refine the contour as close as possible to the boundary of the object. An adaptive scale coefficient for the balloon energy has been introduced. Four levels of resolution have been applied in order to get reproducibility of the contour despite poor different initialisations. The scheme has been applied to segment the regions of interest in CT lung and colon images. The result has been shown to be accurate and reproducible for the cases containing fat, holes and other small high intensity objects inside lung nodules as well as colon polyps.

  15. 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)

    1996-08-01

    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

  16. 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...... hazardous lubricants in cold, warm and hot forging as well as sheet forming and punching/blanking with new, less harmful lubricants.......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...

  17. 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...

  18. 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...

  19. Risk matrix model applied to the outsourcing of logistics' activities

    Fouad Jawab

    2015-09-01

    Full Text Available Purpose: This paper proposes the application of the risk matrix model in the field of logistics outsourcing. Such an application can serve as the basis for decision making regarding the conduct of a risk management in the logistics outsourcing process and allow its prevention. Design/methodology/approach: This study is based on the risk management of logistics outsourcing in the field of the retail sector in Morocco. The authors identify all possible risks and then classify and prioritize them using the Risk Matrix Model. Finally, we have come to four possible decisions for the identified risks. The analysis was made possible through interviews and discussions with the heads of departments and agents who are directly involved in each outsourced activity. Findings and Originality/value: It is possible to improve the risk matrix model by proposing more personalized prevention measures according to each company that operates in the mass-market retailing. Originality/value: This study is the only one made in the process of logistics outsourcing in the retail sector in Morocco through Label’vie as a case study. First, we had identified as thorough as we could all possible risks, then we applied the Risk Matrix Model to sort them out in an ascending order of importance and criticality. As a result, we could hand out to the decision-makers the mapping for an effective control of risks and a better guiding of the process of risk management.

  20. Carbon-based tribofilms from lubricating oils

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

    2016-08-01

    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.

  1. Self lubricating fluid bearings

    The invention concerns self lubricating fluid bearings, which are used in a shaft sealed system extending two regions. These regions contain fluids, which have to be isolated. A first seal is fluid tight for the first region between the carter shaft and the shaft. The second seal is fluid tight between the carter and the shaft, it communicates with the second region. The first fluid region is the environment surrounding the shaft carter. The second fluid region is a part of a nuclear reactor which contains the cooling fluid. The shaft is conceived to drive a reactor circulating and cooling fluid

  2. 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

    2013-11-01

    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'. PMID:24153370

  3. 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

    2013-11-01

    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’.

  4. Lubrication of soft viscoelastic solids

    Pandey, Anupam; Venner, Kees; Snoeijer, Jacco

    2015-01-01

    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. Technological lubricating means: Evolution of materials and ideas

    Godlevskiy, Vladimir A.

    2016-03-01

    The main stages of technological lubricating material development from ancient times to date are described. How the chemical composition of these products changed with time, how new ideas revealing the physical and chemical basics of external media that influence the mechanical processing of materials appeared, how these ideas explained the differences between traditional tribology and specific technology of metal processing are discussed. The question of the possible realization of Rehbinder's adsorption effect in contact zone is also stated. The description of a very captivating problem is related to the explanation of the mechanism of lubricant penetration into the contact zone between the material being processed and the tool. The birth and development of the hypothesis of microcapillary penetration of the lubricant into the dynamically changed intersurface clearance that has finally led to formulating the "necessary kinetic condition of the lubricating activity" is relayed.

  6. Nanorheometry of Molecularly Thin Liquid Lubricant Films Coated on Magnetic Disks

    Shintaro Itoh

    2012-01-01

    Full Text Available Molecularly thin lubricant films are used for the lubrication of head disk interfaces in hard disk drives. The film thickness is reduced to 1-2 nm to minimize the magnetic spacing, and optimal, precise design is required to obtain sufficient lubrication. However, until now, there was no generally applicable method for investigating such thin films. Therefore, we developed a highly sensitive shear force measuring method and have applied it to the viscoelastic measurement of lubricant films coated on magnetic disk surfaces. In this paper, we review the method and summarize the useful findings we have demonstrated so far.

  7. [Research activities in applied mathematics, fluid mechanics, and computer science

    1995-01-01

    This report summarizes research conducted at the Institute for Computer Applications in Science and Engineering in applied mathematics, fluid mechanics, and computer science during the period April 1, 1995 through September 30, 1995.

  8. Recent applied field research activities carried out in tropical Africa

    Goriup, S.; van der Kaay, H. J.

    1984-01-01

    A review has been undertaken of applied field research in malaria in tropical Africa from 1975 onwards, the aim being to show recent trends and to emphasize the needs for further research in support of malaria control.

  9. Automotive gear oil lubricant from soybean oil

    The use of lubricants that are based on renewable materials is rapidly increasing. Vegetable oils have good lubricity, wear protection and low volatility which are desired properties for automotive gear lubricant applications. Soybean oil is used widely in the lubricant industry due to its properti...

  10. Active Polyhedron: Surface Evolution Theory Applied to Deformable Meshes

    Slabaugh, G. G.; Unal, G.B.

    2005-01-01

    This paper presents a novel 3D deformable surface that we call an active polyhedron. Rooted in surface evolution theory, an active polyhedron is a polyhedral surface whose vertices deform to minimize a regional and/or boundarybased energy functional. Unlike continuous active surface models, the vertex motion of an active polyhedron is computed by integrating speed terms over polygonal faces of the surface. The resulting ordinary differential equations (ODEs) provide improved robustness to noi...

  11. Advances in lubrication technology and modelling. Novel nanoscale friction modifiers - Piezoviscosity effect in EHL contacts

    Petrone, Vincenzo

    2014-01-01

    2012 - 2013 Lubricant additives have an important influence on the lubrication performances. These additives are active ingredients which can be added during a blending process to base oils in order either to enhance the existing performance of the base fluids or to impart new properties that the base fluids lack. In modern industry, the ever growing demand on the duration and efficiency of machineries stimulates the research for lubricant additives with better performance. At the same tim...

  12. Controllable Lubrication for Main Engine Bearings Using Mechanical and Piezoelectric Actuators

    Estupinan, Edgar; Santos, Ilmar

    2012-01-01

    Although mechatronic systems are nowadays implemented in a large number of systems in vehicles, active lubrication systems are still incipient in industrial applications. This study is an attempt to extend the active lubrication concept to combustion engines and gives a theoretical contribution t...

  13. Durability evaluation of perfluoropolyether-lubricant-coated protective diamond-like carbon film by the lateral vibration friction test

    An investigation of the perfluoropolyether (PFPE) lubricant effect on the tribological properties of diamond-like carbon (DLC) film magnetic hard disks was conducted. On the basis of friction force microscopy techniques, we carried out lateral oscillation wear tests to detect DLC film disks with and without PFPE lubricant. The results reveal that the DLC film without lubricant easily fractures and swells. In contrast, the transfer of free lubricant and the progressive destruction of bonding lubricant were observed on the DLC film coated with a PFPE lubricant. The dynamic deformation and durability evaluation of the PFPE lubricant and DLC film system were observed in the lateral oscillation wear test by changing the experimental load and amplitude of lateral vibration applied to a cantilever tip. The destruction of the PFPE-DLC film occurred in the test of the 10 nm oscillation amplitude due to the breaking off of the molecular chain of PFPE

  14. Forging tools modification with graphene-like solid lubricant nanoparticles

    V. Leshchynsky

    2010-11-01

    Full Text Available Purpose: Working conditions of forging tools have become severer with the years. To increase their wear andheat resistance the surface of the tool is coated by CVD/PVD methods. Relatively high friction coefficientof coatings results in high friction losses and low durability of coating films due to high shear stress at tool–workpiece interface. That is why improved self-lubricating system should be developed. Combination of moderncoatings (nanostructured, nanolayers, nanocomposites, etc. with self-lubricating tool design and application ofsolid lubricant MoS2 and WS2 graphene-like nanoparticles is very promising and effective way to solve existingforging tool problems.Design/methodology/approach: Laser micro-machining technology was applied to fabricate the network ofmicro-channels which serve like reservoirs for encapsulation of solid lubricant nanoparticles into tool body.Wide ranges of tribological tests on T-10 ball-on-disc tester were carried out to define the optimal geometryand network configuration of micro-channels ensuring generation of a lubricious transfer film at the tribologicalcontact.Findings: As a result, increased tool durability and high forging precision could be reached. Analysis of failuremechanisms for different forging tools were carried out. It was found that one of the important reasons of toolwear is a high friction coefficient between treated material and the tool. Graphene-like nanoparticles of MoS2solid lubricant were produced by Rolling Cleavage Technology. Paper consist SEM, TEM and AFM analysis ofapplied coatings and solid lubricant particles.Research limitations/implications: The continuous supply to a sliding area of nanoparticles will be for thefirst time applied to decrease high shear stress at an interface between forging tool and treated material.Thenext research step will be the transfer of the developed methods of self-lubrication from samples to real coldforging tools.Originality/value: Analysis of

  15. Elasto hydrodynamic lubrication by traction fluid applied to the design of a continuously variable toroidal transmission; La lubrification elastohydrodynamique par un fluide de traction appliquee a la conception d'un variateur toroidal

    Makala, J.; Villechaise, B. [Poitiers Univ., Lab. de Mecanique des Solides, UMR CNRS 6610, 86 (France); Dalmaz, G.; Chaomleffel, J.P. [Institut National des Sciences Appliquees (INSA), Lab. de Mecanique des Contacts, UMR CNRS 5514, 69 - Villeurbanne (France); Kargar, K. [Renault, Dir. de la Recherche, Technocentre, 78 - Guyancourt (France)

    2001-07-01

    Continuously variable toroidal transmissions for automotive use has been the focus of considerable research and development efforts in recent years. They can bring improved fuel economy benefit under good speed ratio changes for automotive propulsion systems in which engines can produce their power under optimum conditions. In this transmission, power is transmitted by means of lubricated point contacts that transmit friction forces. A special fluid, named traction fluid, is used to develop a high friction coefficient at high pressure. The problems in this context are the power efficiency and the evaluation of the mechanism in term of performance. Some elements like roller bearings or gears are lubricated by the same fluid. They are the cause of important power dissipations in their contacts that decrease the transmission efficiency. To predict these power losses, a theoretical model of traction fluid behaviour and the best experimental analysis of rheological fluid properties are needed In order to be close to real working conditions, both in the transmission and the roller bearing contacts, a specific apparatus that can give simultaneously friction forces and film thicknesses is used. (authors)

  16. Applying an Activity System to Online Collaborative Group Work Analysis

    Choi, Hyungshin; Kang, Myunghee

    2010-01-01

    This study determines whether an activity system provides a systematic framework to analyse collaborative group work. Using an activity system as a unit of analysis, the research examined learner behaviours, conflicting factors and facilitating factors while students engaged in collaborative work via asynchronous computer-mediated communication.…

  17. Applying activity-based costing in long-term care.

    Wodchis, W P

    1998-01-01

    As greater numbers of the elderly use health services, and as health care costs climb, effective financial tracking is essential. Cost management in health care can benefit if costs are linked to the care activities where they are incurred. Activity-based costing (ABC) provides a useful approach. The framework aligns costs (inputs), through activities (process), to outputs and outcomes. It allocates costs based on client care needs rather than management structure. The ABC framework was tested in a residential care facility and in supportive housing apartments. The results demonstrate the feasibility and advantages of ABC for long term care agencies, including community-based care. PMID:10339203

  18. Structural lubricity under ambient conditions

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

    2016-01-01

    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. PMID:27350035

  19. Microbial solar cells: applying photosynthetic and electrochemically active organisms

    Strik, D.P.B.T.B.; Timmers, R.A.; Helder, M.; Steinbusch, K.J.J.; Hamelers, H.V.M.; Buisman, C.J.N.

    2011-01-01

    Microbial solar cells (MSCs) are recently developed technologies that utilize solar energy to produce electricity or chemicals. MSCs use photoautotrophic microorganisms or higher plants to harvest solar energy, and use electrochemically active microorganisms in the bioelectrochemical system to gener

  20. Biodegradable lubricants for road vehicles

    Schramm, J. [Denmark Technical Univ., Lyngby (Denmark). Dept. of Mechanical Engineering

    2004-07-01

    This presentation outlined the characteristics of biolubricants and their use in vehicles. Experiments with compression ignition (CI) and spark ignition (SI) engines were also presented. Biolubes can be used in 4-stroke and 2-stroke engines, bearing compressors and hydraulic equipment. Studies have shown that biolubes do not cause unusual engine wear. They are produced from biomass, with the base material being vegetable oils and synthetic esters. Conventional lubricants are produced from fossil fuels, with the base material being mineral oils, polyglycol or synthetic ester. This presentation rated the characteristics of various lubricants in terms of viscosity temperature behaviour, low temperature behaviour, liquid range, oxidation stability, thermal stability, volatility, fire resistance, hydrolytic stability, corrosion protection, seal material compatibility, paints compatibility, miscibility with mineral oil, solubility of additives, lubricating properties, toxicity, and biodegradability. The environmental impacts of biolubes regarding emissions of carbon dioxide, nitrous oxide and particulate matter were discussed along with the impact of combining biolubes with alternative fuels. The future beneficial applications include outboard engines, off road vehicle engines and road vehicle engines. Currently, vegetable oil based biolubricants are 2 to 3 times more expensive than mineral based oils, and synthetic lubricants are even more expensive. It was suggested that future studies should examine the biodegradability of used lubricants, the performance of biodegradable lubricants, alternative fuels and fuel economy. tabs., figs.

  1. Analysis on mechanism of thin film lubrication

    ZHANG Chaohui; LUO Jianbin; HUANG Zhiqiang

    2005-01-01

    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.

  2. "Dear Ann ..." An Activity for Synthesizing and Applying Interpersonal Concepts

    Brule, Nancy J.

    2007-01-01

    All students struggle with interpersonal based problems, be it a troublesome roommate, problems with a partner, conflict with a significant other, or relational issues with parents or children. The interpersonal communication classroom can be enhanced by discussing these problems and experiences. This article presents an activity that aims to (1)…

  3. Molecular-Scale Lubricants for Micromachine Applications: Final Report

    Burns, A.R.; Dugger, M.T.; Houston, J.E.; Lopez, G.P.; Mayer, T.M.; Michalske, T.A.; Miller, S.L.; Sniegowski, J.J.; Stevens, M.J.; Zhou, Y.

    1998-12-01

    The nature of this work was to develop the physics and chemistry base for understanding molecular-scale lubricants used to reduce of friction- and adhesion-induced failure in silicon micromachines (MEMS). We acquired this new knowledge by tailoring the molecular properties of the lubricants, applying local probes that can directly monitor the response of lubricants in contact conditions, and evaluating the performance of model lubricants MEMS devices. Model lubricants under investigation were the silane coupling agents that form monolayer films on native oxide silicon surfaces, which is the substrate in MEMS. These molecules bind via strong surface bonds and produce a layer of hydro- or fluoro-carbon chains normal to the substrate. "Tailoring" the lubricants entails modifying the chain length, the chain chemical reactivity (H or F), and the density of chain structures. Thus much effort went into understanding the surface chemistry of silane-silicon oxide coupling. With proximal probes such as atomic force microscopy (AFM), interracial force microscopy (FM), and shear force microscopy in combination with IFM, we examined the frictional and adhesive properties of the silane films with very high spatial resolution (< 100 nm) and sensitivity. MEMS structures are treated with silanes under identical conditions, and examined for friction and adhesion under operating conditions. Proper assessment of the lubricants required quantitative analysis of MEMS performance at high speeds and long operating times. Our proximal probe measurements and WS performance analyses form a very important link for future molecular dynamics simulations, that, in turn, should be able to predict MEMS performance under all conditions.

  4. Applied research and development of neutron activation analysis

    This report is written for results of research and development as follows : improvement of neutron irradiation facilities, counting system and development of automation system and capsules for NAA in HANARO ; improvement of analytical procedures and establishment of analytical quality control and assurance system; applied research and development of environment, industry and human health and its standardization. For identification and standardization of analytical method, environmental biological samples and polymer are analyzed and uncertainity of measurement are estimated. Also data intercomparison and proficency test were performed. Using airborne particulate matter chosen as a environmental indicators, trace elemental concentrations of sample collected at urban and rural site are determined and then the calculation of statistics and the factor analysis are carried out for investigation of emission source. International cooperation research project was carried out for utilization of nuclear techniques

  5. Applied research and development of neutron activation analysis

    Chung, Yong Sam; Moon, Jong Hwa; Kim, Sun Ha; Bak, Sung Ryel; Park, Yong Chul; Kim, Young Ki; Chung, Hwan Sung; Park, Kwang Won; Kang, Sang Hun

    2000-05-01

    This report is written for results of research and development as follows : improvement of neutron irradiation facilities, counting system and development of automation system and capsules for NAA in HANARO ; improvement of analytical procedures and establishment of analytical quality control and assurance system; applied research and development of environment, industry and human health and its standardization. For identification and standardization of analytical method, environmental biological samples and polymer are analyzed and uncertainity of measurement are estimated. Also data intercomparison and proficency test were performed. Using airborne particulate matter chosen as a environmental indicators, trace elemental concentrations of sample collected at urban and rural site are determined and then the calculation of statistics and the factor analysis are carried out for investigation of emission source. International cooperation research project was carried out for utilization of nuclear techniques.

  6. Neutron activation analysis applied to nutritional and foodstuff studies

    Neutron Activation Analysis, NAA, has been successfully used on a regularly basis in several areas of nutrition and foodstuffs. NAA has become an important and useful research tool due to the methodology's advantages. These include high accuracy, small quantities of samples and no chemical treatment. This technique allows the determination of important elements directly related to human health. NAA also provides data concerning essential and toxic concentrations in foodstuffs and specific diets. In this paper some studies in the area of nutrition which have been carried out at the Neutron Activation Laboratory of IPEN/CNEN-SP will be presented: a Brazilian total diet study: nutritional element dietary intakes of Sao Paulo state population; a study of trace element in maternal milk and the determination of essential trace elements in some edible mushrooms. (author)

  7. Study the active site of flavonoid applying radiation chemistry

    Flavonoid are a large and important class of naturally occurring, low molecular weight benzo-γ-pyrone derivatives which are reported to have a myriad of biological activities, but the study on the active sites of flavonoids is still ambiguous. In this paper, rutin, quercetin and baicalin have been selected as model compounds. It is well known that rutin is used in inhibiting arteriosclerosis and baicalin is antibacterial and antiviral. They have similar basic structure, but their medicinal properties are so different, why? As most flavonoids contain carbonyl group, which can capture electron effectively, we predict that flavonoids can capture electron to form radical anion. The formation of anion radical may have influence on the mitochondrial electron transport chain. The difference in the ability of forming anion radical may cause the difference in their medicinal effects. (author)

  8. How are Derivative Accounting Applied for Hedging Activities?

    Doan Van Dinh; Guangming Gong

    2013-01-01

    The derivative instruments accounting plays an important role in the development of the financial instruments markets, commodity market and in the risk management process. Because, the close relationship between the methods of derivative instruments accounting and the derivative instruments in the financial markets, commodity market for hedging activities. Moreover, they bring the relevance and reliability of Financial statements. Application of derivative instruments accounting is an essenti...

  9. Management of female handball players' activity applying interactive technologies

    Frolova L.S.; Glazyrin I.D.; Petrenko Y.O.; Rudenko E.; Udod M.

    2012-01-01

    The efficiency of developed methods for the control of female handball players' readiness to competitive activity was determined. The opportunities of team management regarding the specification of playing role, the formation of the starting line of players and the replacement according to game priorities in attack or defense were considered. The availability of the adequate zone of handball players' mobilizing readiness that allows to have a significant influence on individual effectiveness ...

  10. Management of female handball players' activity applying interactive technologies

    Frolova L.S.

    2012-04-01

    Full Text Available The efficiency of developed methods for the control of female handball players' readiness to competitive activity was determined. The opportunities of team management regarding the specification of playing role, the formation of the starting line of players and the replacement according to game priorities in attack or defense were considered. The availability of the adequate zone of handball players' mobilizing readiness that allows to have a significant influence on individual effectiveness in the conditions of optimal management and to increase the quality of team game was determined.

  11. High precision methods of neutron activation analysis applied to geochemistry

    Neutron activation analysis is a technique for measuring abundances of chemical elements, which differs from other methods in that it is based upon nuclear reactions instead of chemistry. This characteristic has special relevance for geochemistry because of its inherent sensitivity for trace elements which cannot be reached by other methods. 99% of the earth's crust is made up of just 8 elements, whereas the remaining 1% must accommodate 70-odd rock building trace elements of which about half can be measured by neutron activation analysis. In recent years, there has been much interest in these trace elements because they encompass diverse chemical properties. The present discussion of the technique is based upon more than 15 years of experience at the Lawrence Berkeley Laboratory and The Hebrew University of Jerusalem. This is not meant to intimate that the practices in other laboratories do not merit attention. Perhaps our approach differs from other published work in the emphasis given to sources of error and learning how to control them

  12. TRIBOLOGICAL PROPERTIES OF CrN COATING UNDER LUBRICATION CONDITIONS

    JANUSZ LUBAS

    2012-01-01

    The paper presents research results of the influence of CrN coating on the friction parameters in friction pairs under lubricated friction conditions. The formed CrN homogeneous coating and CrN-steel 46Cr2 "ring" structure coating was matched under test conditions with a counterpart made from SAE-48 and SAE-783 bearing alloys. Tested sliding pairs were lubricated with 5W/40 Lotos synthetic engine oil. The tribological test was conducted on block-on-ring tester. The applied modification techno...

  13. Optical Imaging of Water Condensation on Lubricant Impregnated Micropillar Arrays

    Kajiya, Tadashi; Schellenberger, Frank; Papadopoulos, Periklis; Vollmer, Doris; Butt, Hans-Jürgen

    2015-11-01

    We explored the condensation of water drops on a lubricant-impregnated surface, i.e., a micropillar patterned surface impregnated with a ionic liquid. Growing drops were imaged in 3D using a laser scanning confocal microscope equipped with a temperature and humidity control. On a lubricant-impregnated hydrophobic micropillar array, different stages of condensation can be discriminated: - Nucleation on a lubricant surface. - Regular alignement between micropillars and formation of a three-phase contact line on a bottom of the substrate. - Deformation and bridging by coalescence, leading to a detachment of the drops from the bottom substrate to pillars'top faces. However, on a lubricant-impregnated hydrophilic micropillar array, the condensed water covers the micropillars by dewetting the lubricant. As a result, the surface loses its slippery property. Our results provide fundamental concepts how these solid/liquid hybrid surfaces can be applied for facile removal of condensed water, as well as necessity of the appropriate surface treatment. Financial support from ERC for the advanced grant 340391-SUPRO is gratefully acknowledged.

  14. Gear Mesh Loss-of-Lubrication Experiments and Analytical Simulation

    Handschuh, Robert F.; Polly, Joseph; Morales, Wilfredo

    2011-01-01

    An experimental program to determine the loss-of-lubrication (LOL) characteristics of spur gears in an aerospace simulation test facility has been completed. Tests were conducted using two different emergency lubricant types: (1) an oil mist system (two different misted lubricants) and (2) a grease injection system (two different grease types). Tests were conducted using a NASA Glenn test facility normally used for conducting contact fatigue. Tests were run at rotational speeds up to 10000 rpm using two different gear designs and two different gear materials. For the tests conducted using an air-oil misting system, a minimum lubricant injection rate was determined to permit the gear mesh to operate without failure for at least 1 hr. The tests allowed an elevated steady state temperature to be established. A basic 2-D heat transfer simulation has been developed to investigate temperatures of a simulated gear as a function of frictional behavior. The friction (heat generation source) between the meshing surfaces is related to the position in the meshing cycle, the load applied, and the amount of lubricant in the contact. Experimental conditions will be compared to those from the 2-D simulation.

  15. Active Learning Techniques Applied to an Interdisciplinary Mineral Resources Course.

    Aird, H. M.

    2015-12-01

    An interdisciplinary active learning course was introduced at the University of Puget Sound entitled 'Mineral Resources and the Environment'. Various formative assessment and active learning techniques that have been effective in other courses were adapted and implemented to improve student learning, increase retention and broaden knowledge and understanding of course material. This was an elective course targeted towards upper-level undergraduate geology and environmental majors. The course provided an introduction to the mineral resources industry, discussing geological, environmental, societal and economic aspects, legislation and the processes involved in exploration, extraction, processing, reclamation/remediation and recycling of products. Lectures and associated weekly labs were linked in subject matter; relevant readings from the recent scientific literature were assigned and discussed in the second lecture of the week. Peer-based learning was facilitated through weekly reading assignments with peer-led discussions and through group research projects, in addition to in-class exercises such as debates. Writing and research skills were developed through student groups designing, carrying out and reporting on their own semester-long research projects around the lasting effects of the historical Ruston Smelter on the biology and water systems of Tacoma. The writing of their mini grant proposals and final project reports was carried out in stages to allow for feedback before the deadline. Speakers from industry were invited to share their specialist knowledge as guest lecturers, and students were encouraged to interact with them, with a view to employment opportunities. Formative assessment techniques included jigsaw exercises, gallery walks, placemat surveys, think pair share and take-home point summaries. Summative assessment included discussion leadership, exams, homeworks, group projects, in-class exercises, field trips, and pre-discussion reading exercises

  16. Thermal, Squeezing and Compressibility Effects in Lubrication of Asymmetric Rollers

    D. Prasad

    2014-09-01

    Full Text Available Hydrodynamically heavily loaded rigid cylindrical rollers, lubricated by a thin compressible fluid film, are investigated for normal squeezing motion and cavitations. The lubricant is assumed to follow the non-Newtonian power-law fluid model where consistency and density of the lubricant vary with one dimensional pressure and temperature. The modified Reynolds pressure equation and thermal energy equation are derived and solved simultaneously by R-K Fehlberg method. Secant method is also applied in order to enforce the boundary condition at the outlet. It is observed that temperature has significant effects on consistency and density both. It is also to be noted that compressibility effect is even more significant when squeezing is taken into account.

  17. Applying activity-based costing to the nuclear medicine unit.

    Suthummanon, Sakesun; Omachonu, Vincent K; Akcin, Mehmet

    2005-08-01

    Previous studies have shown the feasibility of using activity-based costing (ABC) in hospital environments. However, many of these studies discuss the general applications of ABC in health-care organizations. This research explores the potential application of ABC to the nuclear medicine unit (NMU) at a teaching hospital. The finding indicates that the current cost averages 236.11 US dollars for all procedures, which is quite different from the costs computed by using ABC. The difference is most significant with positron emission tomography scan, 463 US dollars (an increase of 96%), as well as bone scan and thyroid scan, 114 US dollars (a decrease of 52%). The result of ABC analysis demonstrates that the operational time (machine time and direct labour time) and the cost of drugs have the most influence on cost per procedure. Clearly, to reduce the cost per procedure for the NMU, the reduction in operational time and cost of drugs should be analysed. The result also indicates that ABC can be used to improve resource allocation and management. It can be an important aid in making management decisions, particularly for improving pricing practices by making costing more accurate. It also facilitates the identification of underutilized resources and related costs, leading to cost reduction. The ABC system will also help hospitals control costs, improve the quality and efficiency of the care they provide, and manage their resources better. PMID:16102243

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

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

    2013-10-31

    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.

  19. Top-of-Rail lubricant

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

    2000-07-14

    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.

  20. Cost-Cutting Powdered Lubricant

    2005-01-01

    Scientists at NASA's Glenn Research Center developed a high-temperature, solid lubricant coating material that is saving the manufacturing industry millions of dollars. The material came out of 3 decades of tribological research, work studying high-temperature friction, lubrication, and the wearing of interacting surfaces that are in relative motion. It was developed as a shaft coating deposited by thermal spraying to protect foil air bearings used in oil-free turbomachinery, like gas turbines, and is meant to be part of a larger project: an oil-free aircraft engine capable of operating at high temperatures with increased reliability, lowered weight, reduced maintenance requirements, and increased power. This advanced coating, PS300, is a self-lubricating bearing material containing chromium oxide, with additions of a low-temperature start up lubricant (silver) and a high-temperature lubricant, making it remarkably stable at high temperatures, and better suited than previously available materials for high-stress conditions. It improves efficiency, lowers friction, reduces emissions, and has been used by NASA in advanced aeropropulsion engines, refrigeration compressors, turbochargers, and hybrid electrical turbogenerators. PS300 is ideal in any application where lowered weight and reduced maintenance are desired, and high-temperature uses and heavy operating speeds are expected. It has notable uses for the Space Agency, but it has even further-reaching potential for the industrial realm.

  1. Studies of lubricants and punch design in punching of stainless steel

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

    Environmentally hazardous lubricants such as chlorinated paraffin oils are often applied in punching and blanking operations especially involving stainless steel workpiece materials. This is due to the fact that punching and blanking are among the tribologically most difficult forming operations...

  2. Metalworking corrosion inhibition/drawing lubricant

    Lipinski, H.F.; Wantling, S.J.

    1980-05-06

    A metalworking lubricant composition is disclosed which is effective as both a corrosion inhibitor and drawing lubricant and comprises a mineral oil and an additive combination of barium lanolate soap and barium sulfonate.

  3. How to evaluate solid lubricant films using a pin-on-disk tribometer

    Fusaro, R. L.

    1986-01-01

    Over the years, the author has evaluated and compared hundreds of solid lubricant films using a pin-on-disk tribometer. The intent of this paper is to describe to the reader experimental techniques and some of parameters that have been observed to be important for the evaluation and development of new solid lubricant films. Pin-on-disk tribometers will be described and discussed as will experimental methods for evaluating solid lubricant materials. Methods of preparing surfaces for the coating of the thin films and different methods for applying the films will be reviewed. Factors that affect solid lubricant performance will also be discussed. Two different macroscopic mechanisms of solid lubricant film wear exist. These will be characterized schematically, and methods of measuring wear will be examined.

  4. Effect of surface condition on the formation of solid lubricating films at high temperatures

    Hanyaloglu, Bengi; Graham, E. E.

    1992-01-01

    Solid films were produced on active metal or ceramic surfaces using lubricants (such as tricresyl phosphate) delivered as a vapor at high temperatures, and the lubricity of these deposits under different dynamic wear conditions was investigated. A method is described for chemically activating ceramic surfaces resulting in a surface that could promote the formation of lubricating polymeric derivative of TCP. Experiments were carried out to evaluate the wear characteristics of unlubricated cast iron and of Sialon ceramic at 25 and 280 C, and lubricated with a vapor of TCP at 280 C. It is shown that continuous vapor phase lubrication of chemically treated Sialon reduced its coefficient of friction from 0.7 to less than 0.1.

  5. Biodegradation and toxicological evaluation of lubricant oils

    Ivo Shodji Tamada; Paulo Renato Matos Lopes; Renato Nallin Montagnolli; Ederio Dino Bidoia

    2012-01-01

    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...

  6. CYLINDER AND SYSTEM LUBRICATING OILS

    ION ADRIAN GIRBA

    2016-06-01

    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. :

  7. Tethered Lubricants for Small Systems

    Lynden A. Archer

    2006-01-09

    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.

  8. Growth and opportunities in the lubricants business in Asia

    The demand for lubricants is increasing faster in Asia than any other part of the world. This development is being propelled largely by the expansion of the transportation and manufacturing sectors. By the year 2000, lubricant consumption in Asia will exceed that of Western Europe, Africa and the Middle East combined. Aside from this growth, most of the region is shifting from very low quality to higher quality value-added products. In view of these factors, there has been an explosion of activity over the past few years as lubricant blenders and additive suppliers attempt to position themselves within the market. Over the past year, Chem Systems has undertaken an extensive study of the lubricants business in East Asia, focusing on the evolution of this complex market structure and the identification of attractive opportunities. The overview presented in this paper is a product of these efforts. Whether you are a multinational oil company, independent blender, national oil company or multinational additive suppler, the questions are the same when developing a strategy for the region: regional overview of lubricant business structure; outlook for Asian demand; profile of lube/additives businesses; and successful competition--what is required?

  9. Laboratory services series: a lubrication program

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

    1976-05-01

    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.

  10. A new lubricant carrier for metal forming

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

    2009-01-01

    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...... extrusion at high reduction and excessive stroke comparing with conventionally lubrication using phosphate coating and soap....

  11. Lubrication greases for nuclear reactors

    Lubricating greases are essential components of many machines used in nuclear power plants. Where these machines are subject to radiation the life of the grease will be reduced due to deterioration of the components of the grease. According to the chemical nature of the grease used a greater or lesser resistance to radiation will be observed. Tests and techniques to evaluate the performance of greases before and after irradiation are described. The results of these tests show that conventional premium greases will resist comparatively low levels of irradiation, whilst greases formulated from correctly selected components can tolerate quite high levels of radiation permitting the machines they lubricate to attain their designed service lives

  12. New approach in lubrication engineering using neutron reflectometry

    According to historic papers in lubrication engineering, lubrication modes between two solids are essentially classified into three groups - boundary lubrication, mixed lubrication and full-film lubrication. This paper proposed some novel approaches for elucidation of lubrication phenomena using neutron reflectometry. For the studies on boundary lubrication, the neutron reflectometry is helpful to in-situ observe the 'absorbed layer' near the solid surface, while for the studies on full-film lubrication, it can reveal the density of lubricants at the solid-liquid interface. Those information will help to clarify the friction mechanism under lubrication in the field of tribology. (author)

  13. Self lubrication of bitumen froth in pipelines

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

    1997-12-31

    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.

  14. Activity Theory applied to Global Software Engineering: Theoretical Foundations and Implications for Tool Builders

    Tell, Paolo; Ali Babar, Muhammad

    2012-01-01

    Although a plethora of tools are available for Global Software Engineering (GSE) teams, it is being realized increasingly that the most prevalent desktop metaphor underpinning the majority of tools have several inherent limitations. We have proposed that Activity-Based Computing (ABC) can be a...... applying activity theory to GSE. We analyze and explain the fundamental concepts of activity theory, and how they can be applied by using examples of software architecture design and evaluation processes. We describe the kind of data model and architectural support required for applying activity theory in...

  15. Longevity Of Dry Film Lubricants

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

    1993-01-01

    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.

  16. Vegetable oil basestocks for lubricants

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

    2011-07-01

    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).

  17. Automotive Cooling and Lubricating Systems.

    Marine Corps Inst., Washington, DC.

    This correspondence course, originally developed for the Marine Corps, is designed to provide new mechanics with a source of study materials to assist them in becoming more proficient in their jobs. The course contains four study units covering automotive cooling system maintenance, cooling system repair, lubricating systems, and lubrication…

  18. Thin Film Solid Lubricant Development

    Benoy, Patricia A.

    1997-01-01

    Tribological coatings for high temperature sliding applications are addressed. A sputter-deposited bilayer coating of gold and chromium is investigated as a potential solid lubricant for protection of alumina substrates during sliding at high temperature. Evaluation of the tribological properties of alumina pins sliding against thin sputtered gold films on alumina substrates is presented.

  19. Full Life Wind Turbine Gearbox Lubricating Fluids

    Lutz, Glenn A.; Jungk, Manfred; Bryant, Jonathan J.; Lauer, Rebecca S.; Chobot, Anthony; Mayer, Tyler; Palmer, Shane; Kauffman, Robert E.

    2012-02-28

    using PFPE as the gearbox lubricating fluid. It is important to note the largest portion of savings comes in Levelized Replacement Cost, which is dictated by the assumption on gearbox reliability. Thus, verifying and quantifying the potential of PFPE fluid to effect gearbox reliability is the key assumption that would need to be further validated. In summary the proof of concept to use PFPE fluid as wind turbine gear box lubricant was validated with this project. The increase in life time was qualitatively demonstrated and this supports the need for future activity of field trials and laboratory aging studies to quantify the predicted 20 year life. With micro-pitting being the major failure mechanism in the last years, recent publications show that white etch cracking of bearings seem to have the highest impact on wind turbine reliability. With its higher film thicknesses compared to PAO reference oils, PFPE fluids have the potential to reduce this failure occurrence as well.

  20. Airlift bioreactor containing chitosan-immobilized Sphingobium sp. P2 for treatment of lubricants in wastewater

    Highlights: ► Sphingobium sp. P2 effectively degraded various lubricant samples. ► Efficiency of Sphingobium sp. P2 increased after immobilization on chitosan. ► High removal efficiency was due to both sorption and degradation processes. ► The immobilized bacteria (4 g L−1) were applied in internal loop airlift bioreactor. ► The bioreactor continuously removed lubricant from emulsified wastewater. - Abstract: An internal loop airlift bioreactor containing chitosan-immobilized Sphingobium sp. P2 was applied for the removal of automotive lubricants from emulsified wastewater. The chitosan-immobilized bacteria had higher lubricant removal efficiency than free and killed-immobilized cells because they were able to sorp and degrade the lubricants simultaneously. In a semi-continuous batch experiment, the immobilized bacteria were able to remove 80–90% of the 200 mg L−1 total petroleum hydrocarbons (TPH) from both synthetic and carwash wastewater. The internal loop airlift bioreactor, containing 4 g L−1 immobilized bacteria, was later designed and operated at 2.0 h HRT (hydraulic retention time) for over 70 days. At a steady state, the reactor continuously removed 85 ± 5% TPH and 73 ± 11% chemical oxygen demand (COD) from the carwash wastewater with 25–200 mg L−1 amended lubricant. The internal loop airlift reactor's simple operation and high stability demonstrate its high potential for use in treating lubricants in emulsified wastewater from carwashes and other industries.

  1. Friction Regimes in the Lubricants Solid-State Regime

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

    1995-01-01

    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 roughness on this transition. The friction measurements showed that in the lubricants solid-state region three lubrication modes can be distinguished: A) full-film lubrication; separation is maintained b...

  2. ELASTOHYDRODYNAMIC LUBRICATION OF LOGARITHMIC PROFILE ROLLER CONTACTS

    2001-01-01

    An account of numerical solutions to the isothermal and flooded elastohydrodynamic lubrication(EHL)of a logarithmic profile roller, which is rolling over a flat plane,is givenThe analysis takes account of sidew ays flow of lubricant in the inlet region of the contactWhen the results are p resented in suitable nondimensional groups,it is shown that more uniformly pre ssure and shape of the film distributing in axial direction is taken place under light loadingAs the increase of the load,the end closure is displayed and the oil pressure rises sharply at the endsThe seal action formed by the end closu re makes the film thickness a littleAnd the minimum film thickness is transfer red from the central to the ends and the value is reduced rapidlyAs the increa se of the speed,the end closure becomes much seriousThe optimum crowning value obtained in EHL state is larger than the design value obtained in elastostatic contact state for the same working conditionsIn order to verify the correctnes s of theory,optical interferometry is applied to measure the oil film thickness between a logarithmic profiled roller and a glass plate under pure rolling condi tionsIt is found the agreement between numerical solutions and experiments is very good

  3. The influence oil film lubrication of the piston-cylinder dynamic

    Adriana Tokar

    2008-10-01

    Full Text Available An analytical study of the dynamics of a piston in a reciprocating engine was conducted. The equation of Reynolds and moving of piston are derived. The analysis, which incorporates a hydrodynamic lubrication model, was applied to M501 diesel engine. The results of this study indicate that piston dynamics were found to be sensitive to piston-cylinder bore clearance, location of the wrist pin and lubricant viscosity, underscoring their importance in engine design.

  4. True Stability of Lubricants Determined Using the Ball-on-Disk Test

    Angela Maria Tortora

    2016-01-01

    Full Text Available True stability of lubricants can be determined when there is minimum change in the contact area and also the intervention of wear debris in the contact zone. Here, we have used the ball-on-disk instrument with the migrating point contact, that is, relative motion between the ball and disk condition to fix the contact area and minimize the wear debris at the contact zone. The jump in the friction coefficient indicates the film failure, which appeared earlier for the motor oil 5W30 compared to 5W40. Such profile was not recorded in absence of relative motion. Therefore, 5W40 was considered to have a better lubricant stability than 5W30. Applying the same test condition to the natural lubricants shows that glycerol has better lubricant stability than glycerol-water mixture. Superior true lubricant stability by glycerol and 5W40 can be related to its high viscosity. However, they were less wear resistant compared to low viscosity lubricants like 5W30 and glycerol-water. We suspect the role of microscopic wear debris at the contact zone for this behavior although it should have been avoided in the migrating point contact condition. Overall, ball-on-disk instrument with a migrating point contact condition is an effective technique to determine the stability of lubricants.

  5. Musculoskeletal modelling of muscle activation and applied external forces for the correction of scoliosis

    Curtin, Maurice; Lowery, Madeleine M.

    2014-01-01

    Background This study uses biomechanical modelling and computational optimization to investigate muscle activation in combination with applied external forces as a treatment for scoliosis. Bracing, which incorporates applied external forces, is the most popular non surgical treatment for scoliosis. Non surgical treatments which make use of muscle activation include electrical stimulation, postural control, and therapeutic exercises. Electrical stimulation has been largely dismissed as a viabl...

  6. Lubricated friction between incommensurate substrates

    Vanossi, Andrea; Santoro, Giuseppe E.; Manini, Nicola; Tosatti, Erio; Braun, O. M.

    2007-01-01

    This paper is part of a study of the frictional dynamics of a confined solid lubricant film - modelled as a one-dimensional chain of interacting particles confined between two ideally incommensurate substrates, one of which is driven relative to the other through an attached spring moving at constant velocity. This model system is characterized by three inherent length scales; depending on the precise choice of incommensurability among them it displays a strikingly different tribological beha...

  7. Wet friction materials and lubricants

    Matsumoto, Takayuki

    1988-02-01

    There are wet and dry friction materials used for friction clutches and friction brakes. Wet friction materials include sintered alloys and semimetallic substances. Paper friction materials which are the most common wet friction materials used in automobiles were studied for their performance and their relation to lubricants. All present paper friction materials are non-asbestos paper friction materials. The requirements for paper friction material performance are as follows: (1) The heat resistance and durability are so high that the material can stand sliding for a long time. (2) The friction curve is flat. (3) The mechanical strength, wear resistance, and resistance to oil pressure are high. (4) The coefficient of friction (particularly, of static friction) is very high. (5) Variations in the coefficient of friction with time are low. The friction characteristics and wear of paper friction materials are influenced by the lubricant used together with the paper friction materials. It is necessary to develop materials which are immune to the influence of the lubricant. (11 figs, 3 tabs, 21 refs)

  8. Used lubricants and ecological problems

    This planet is undergoing a severe ecological crisis. The consequent problems include not only how to prevent the destruction of contemporary civilization, but also how to preserve mankind as a biological species. In the onset of this crisis, used lubricants (ULs) play a role that is by no means the least important. Every year, the worldwide discharge of petroleum products to the biosphere is approximately 6 million tonnes, of which more than 50% consists of ULs. The ecologically dangerous components of both commercial lubricants and used lubricants are the polycyclic aromatic hydrocarbons (PAHs) that are originally present in crude oil; polyhalobiphenyls, mainly polychlorobiphenyls (PCBs) of anthropogenic origin; sulfur- and chlorine-containing additives; a number of biocides; organic compounds of metals (lead, barium, antimony, zinc); and nitrites. These substances are distributed in the atmosphere, water, and soil, entering the food chain and appearing in foodstuffs. Moreover, hydrocarbons of petroleum and synthetic oils with a low degree of biodegradability (10-30%) accumulate in the environment and may shift the ecological equilibrium (accelerated multiplication and mutation of microorganisms that assimilate petroleum products). 32 refs., 1 fig

  9. Effect of Lubricant Additives on the WDLC Coating Structure When Tested in Boundary Lubrication Regime

    Yang, L; Neville, A; Brown, A; Ransom, P; Morina, A

    2015-01-01

    Improvements in coating deposition technology enable the mass production of high-quality diamond-like carbon (DLC) coatings at an industrial scale and also increase their use in lubricated contacts. However, the understanding of the interactions of different lubricant additives with this material is not yet fully developed. This study focuses on several fundamental aspects of the tungsten-doped DLC coating (denoted as WDLC) behaviour under boundary lubrication conditions with model lubricants...

  10. Experimental identification of dynamic coefficients of lightly loaded tilting-pad bearings under several lubrication regimes

    Salazar, Jorge G.; Santos, Ilmar F.

    2016-01-01

    ) radial injection nozzles, (d) displacement sensors and (e) well-tuned digital controllers. A scaled-down industrial rotor featuring active lubrication, composed of a flexible rotor supported by a four-rocker load-between-pads tilting-pad bearing under light load condition, is used for this objective. The......This paper presents the identified dynamic coefficients of a lightly loaded actively lubricated bearing under three lubrication regimes: passive, hybrid and feedback-controlled. The goal is to experimentally demonstrate the feasibility of modifying the bearing dynamic properties via active...... lubrication. Dominated by the latest two regimes, the bearing properties become adjustable or controllable due to the injection of either a constant or variable pressurized oil flow. Such a flow is regulated by a hydraulic control system composed of (a) a high-pressure oil supply unit, (b) servovalves, (c...

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

    Shimizu, I; Martins, P.A.F.; Bay, Niels; Andreasen, Jan Lasson; Bech, Jakob I.

    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...

  12. Experimental rig for measuring lubricant film thickness in rolling bearings

    Zhang, Xingnan; Jablonka, Karolina Anna; Glovnea, Romeo

    2014-01-01

    Electrical capacitance has been applied in the past for measuring the lubricant film thickness in rolling element bearings. The main difficulty arises from the fact that the measured capacitance is a combination of the capacitances of many rolling elements, which come in contact with both the inner and outer rings. Besides, the capacitance of the Hertzian contact itself and the surrounding area must also be separated. It results in a complex system which, in order to be solved for the film ...

  13. Solid lubrication technology of HTGR under helium

    Because Helium is used as coolant in High Temperature Gas-cooled Reactor (HTGR), the change of tribological properties of HTGR structure component under Helium is a big problem. Under Helium, tribological properties of material becomes worse and fluid lubrication can not be used. Bonded solid lubrication film and fusion sintering solid film are used in control rod and can solve the tribological problem well. Methods of replenishment solid lubricant are discussed for continuously operating friction components. The necessity and possibility for solid lubrication film used in Helium fan is also discussed

  14. Lubrication System with Tolerance for Reduced Gravity

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

    2013-01-01

    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.

  15. Aqueous lubrication natural and biomimetic approaches

    Spencer, Nicholas D

    2014-01-01

    Man lubricates mostly with oil. Nature lubricates exclusively with water. Pure water is a poor lubricant, but the addition of proteins, especially glycoproteins, can modify surfaces to make them far more lubricating at slow speeds. Understanding how nature does this, and the physical structures involved, is not only important for the understanding of diseases such as osteoarthritis, but also essential for the successful application of articulating implants, such as hips and knees, as well as the development of medical devices such as catheters and contact lenses. A host of important applicati

  16. Ecotoxicological study of used lubricating oil

    Used lubricating oil is more toxic than crude oil and fuel oil since it contains comparatively high levels of heavy metals and polycyclic aromatic hydrocarbons (PAHs). No detail toxicological study has been conducted to evaluate the hazards of used lubricating oil to the environment. This study reports a battery of bioassays using bacteria (Microtox test and Mutatox test), algae, amphipod and shrimp larvae to determine the toxicity of water soluble fraction of used lubricating oil. The results will be used to formulate a complete and extensive ecotoxicological assessment of the impacts of used lubricating oil on aquatic environment

  17. Lubricant for cold stamping of metal

    Tulik, V.T.; Movshovich, V.S.; Speranskiy, B.S.; Tseloval' nikov, V.M.; Yudovich, S.Z.

    1980-03-19

    Hydrogenated thermally thickened vegetable oil and the product of condensation of triethanolamine with the bottoms of synthetic fatty acids are added to the oil, which contains petroleum oil, lanolin and a nonionogenic wetting agent, in order to increase the lubricating properties and to give it mothballing properties. The contents of the components are in %: lanolin, 10-20; nonionogenic wetting agent, 1-5; vegetable oil, 10-50; product of condensation, 1-5 and petroleum oil to 100%. The lubricant is produced through the introduction of the cited components in petroleum oil heated to 65-75/sup 0/C with careful mixing. Comparative laboratory tests of the lubricant samples were conducted through identifying the degree of drawing, the drawing force and the degree of deformation. The tests showed that the new lubricant has high lubricating and washing properties. Also studied was the corrosion stability in a moisture chamber as compared with I-20 A lubricant. The time after which the corrosion appeared in days for the I-20 A is 1 and the sample of the lubricant, 28. Industrial tests showed that the proposed lubricant may be used in sheet stamping production in the manufacture of complex parts of motor vehicles without the additional application of industrial lubricant in conditions of press production.

  18. Direct observation of lubricant additives using tomography techniques

    Chen, Yunyun; Sanchez, Carlos; Parkinson, Dilworth Y.; Liang, Hong

    2016-07-01

    Lubricants play important roles in daily activities such as driving, walking, and cooking. The current understanding of mechanisms of lubrication, particularly in mechanical systems, has been limited by the lack of capability in direct observation. Here, we report an in situ approach to directly observe the motion of additive particles in grease under the influence of shear. Using the K-edge tomography technique, it is possible to detect particular additives in a grease and observe their distribution through 3D visualization. A commercial grease as a reference was studied with and without an inorganic additive of Fe3O4 microparticles. The results showed that it was possible to identify these particles and track their movement. Under a shear stress, Fe3O4 particles were found to adhere to the edge of calcium complex thickeners commonly used in grease. Due to sliding, the grease formed a film with increased density. This approach enables in-line monitoring of a lubricant and future investigation in mechanisms of lubrication.

  19. Applying Modern Techniques and Carrying Out English .Extracurricular—— On the Model United Nations Activity

    XuXiaoyu; WangJian

    2004-01-01

    This paper is an introduction of the extracurricular activity of the Model United Nations in Northwestern Polyteehnical University (NPU) and it focuses on the application of the modem techniques in the activity and the pedagogical theories applied in it. An interview and questionnaire research will reveal the influence of the Model United Nations.

  20. Energy efficient reduced graphene oxide additives: Mechanism of effective lubrication and antiwear properties

    Gupta, Bhavana; Kumar, N.; Panda, Kalpataru; Dash, S.; Tyagi, A. K.

    2016-01-01

    Optimized concentration of reduced graphene oxide (rGO) in the lube is one of the important factors for effective lubrication of solid body contacts. At sufficiently lower concentration, the lubrication is ineffective and friction/wear is dominated by base oil. In contrast, at sufficiently higher concentration, the rGO sheets aggregates in the oil and weak interlayer sliding characteristic of graphene sheets is no more active for providing lubrication. However, at optimized concentration, friction coefficient and wear is remarkably reduced to 70% and 50%, respectively, as compared to neat oil. Traditionally, such lubrication is described by graphene/graphite particle deposited in contact surfaces that provides lower shear strength of boundary tribofilm. In the present investigation, graphene/graphite tribofilm was absent and existing traditional lubrication mechanism for the reduction of friction and wear is ruled out. It is demonstrated that effective lubrication is possible, if rGO is chemically linked with PEG molecules through hydrogen bonding and PEG intercalated graphene sheets provide sufficiently lower shear strength of freely suspended composite tribofilm under the contact pressure. The work revealed that physical deposition and adsorption of the graphene sheets in the metallic contacts is not necessary for the lubrication.

  1. COMPARATIVE STUDY OF CHELATION VALUE OF SEVENTEEN PERCENT SELF DEVELOPED AND COMMERCIALLY AVAILABLE ROOT CANAL LUBRICANTS

    Ingale Satish Dinkarrao

    2013-06-01

    Full Text Available The main objective of this study is to compare chelation values of 17% self developed & commercially available root canal Lubricants or dental chelating gels as well as to see whether their performance depends on the chelation value or not. The Chelating agent bounds Ca2+ ions of the smear layer & the extent of chelate formation between chelating agent and metal ion is nothing but Chelation Value. Sodium carbonate indicator method is used for determinations of chelation value. Commercially available gel incorporated in this study was File Rite which has little bit higher chelation value. Self developed chelating gel or root canal lubricants have comparatively lower chelation value. Root canal lubricants having higher chelation value should perform better in shaping & cleaning of root canal better. However because of slight difference in chelation value of self developed & commercially available gel, no significant difference was found out as root canal lubricants, when applied in root canal for 5 minutes.

  2. Evaluation of replacement thread lubricants for red lead and graphite in mineral oil

    Jungling, T.L.; Rauth, D.R.; Goldberg, D.

    1998-04-30

    Eight commercially available thread lubricants were evaluated to determine the best replacement for Red Lead and Graphite in Mineral Oil (RLGMO). The evaluation included coefficient of friction testing, high temperature anti-seizing testing, room temperature anti-galling testing, chemical analysis for detrimental impurities, corrosion testing, off-gas testing, and a review of health and environmental factors. The coefficient of friction testing covered a wide variety of factors including stud, nut, and washer materials, sizes, manufacturing methods, surface coatings, surface finishes, applied loads, run-in cycles, and relubrication. Only one lubricant, Dow Corning Molykote P37, met all the criteria established for a replacement lubricant. It has a coefficient of friction range similar to RLGMO. Therefore, it can be substituted directly for RLGMO without changing the currently specified fastener torque values for the sizes, materials and conditions evaluated. Other lubricants did not perform as well as Molykote P37 in one or more test or evaluation categories.

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

    Wiśniewska-Weinert H.

    2015-09-01

    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.

  4. Effect of Applied Potentials on the Activity and Growth of Thiobacillus ferrooxidans

    Natarajan, KA

    1992-01-01

    The effect of applied DC potentials both in the positive and negative range, on the activity and growth of Thiobacillus ferrooxidans, is discussed. In general, application of positive potentials up to +1000 mV in an acid bioleaching medium was found to be detrimental to bacterial activity, while the impression of negative potentials enhanced both their activity and growth through electrochemical regeneration of ferrous ions and an increase in the biomass. Ferrous-ferric ratios in a bioleachin...

  5. A comparison of the tribological behaviour of steel/steel, steel/DLC and DLC/DLC contact when lubricated with mineral and biodegradable oils

    Kalin, Mitjan; Vižintin, Jože

    2015-01-01

    Diamond-like carbon (DLC) coatings, which can nowadays be applied to many highly loaded mechanical components, sometimes need to operate under lubricated conditions. It is reasonable to expect that in steel/DLC contacts, at least the steel counter body will behave according to conventional lubrication mechanisms and will interact with lubricants and additives in the contact. However, in DLC/DLC contacts, such mechanisms are still unclear. For example, the "inertness" of DLC coatings raises se...

  6. Dynamics of SAMs in Boundary Lubrication

    J. Manojlović

    2013-09-01

    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.

  7. A Biomimetic Approach to Lubricate Engineering Materials

    Røn, Troels

    electrostatic repulsion between charged PAA blocks, hindering the facile formation of the lubricating layer under cyclic tribological stress. It is well known that graft copolymers anchor more efficiently to surfaces than their diblock counterparts, thus the synthesis and study on lubricating capabilities of...

  8. 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...

  9. 30 CFR 56.14204 - Machinery lubrication.

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Machinery lubrication. 56.14204 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Machinery and Equipment Safety Practices and Operational Procedures § 56.14204 Machinery lubrication. Machinery...

  10. 30 CFR 57.14204 - Machinery lubrication.

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Machinery lubrication. 57.14204 Section 57... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Machinery and Equipment Safety Practices and Operational Procedures § 57.14204 Machinery lubrication. Machinery...

  11. Lubricity studies with biodiesel and related compounds

    Biodiesel, the alkyl esters of vegetable oils or animal fats, possesses excellent lubricity. This feature has rendered biodiesel of special interest for blending with ultra-low sulfur diesel fuels with poor lubricity. However, some minor components, mainly free fatty acids and monoacylglycerols, of ...

  12. An emulsion lubricant for metallic molds

    Dovzhik, O.I.; Cherkayev, V.G.; Min' kovskiy, M.M.; Romanyuk, V.G.; Shapiro, L.D.; Sokolov, V.A.

    1980-02-26

    An emulsion lubricant for metallic molds used in production of concrete products for eliminating adhesion of concrete with the metallic mold, and to eliminate potential for air pore formation on surface of product, contains lanolin production waste materials. Compos. of lubricant %: Synthetic emulsol oxide 5-10; wastes from lanolin production in conversion to wax 5-10; water the rest.

  13. VOLATILIZED LUBRICANT EMISSIONS FROM STEEL ROLLING OPERATIONS

    The report gives results of a study of the volatilization of lubricants used in steel rolling. Data from nine steel mills were used to: define the volatilized portion of lubricants used in rolling; and prepare total oil, grease, and hydraulic material balances for actual and typi...

  14. Turbulence Models of Hydrodynamic Lubrication

    张直明; 王小静; 孙美丽

    2003-01-01

    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.

  15. Experimental Analysis of Damping and Tribological Characteristics of Nano-CuO Particle Mixed Lubricant in Ball Bearings

    Prakash, E.; Sivakumar, K.

    2015-12-01

    Experimental analysis of damping capacity and tribological characteristics of nano CuO added Servosystem 68 lubricant is attempted. CuO nano particles were synthesized by aqueous precipitation method and characterized. Prior to dispersion into lubricant, CuO nano particles were coated with 0.2 wt.% surfactant (Span-80) to stabilize the nano fluid. Tribological characteristics of particle added lubricant were tested in ASTM D 4172 four ball wear tester. Scanning electron microscopy test results of worn surfaces of nano CuO particle added lubricant were smoother than base lubricant. The particle added lubricant was applied in a new ball bearing and three defected ball bearings. When particle added lubricant was used, the ball defected bearing's vibration amplitude was reduced by 21.94% whereas it was 16.46% for new bearing and was ≤ 11% for other defected bearings. The formation of protection film of CuO over ball surface and regime of full film lubrication near the ball zone were observed to be reason for improved damping of vibrations.

  16. Applied nuclear physics group - activities report. 1977-1997; Grupo de fisica nuclear aplicada - relatorio de atividades. 1977-1997

    Appoloni, Carlos Roberto

    1998-06-01

    This report presents the activities conducted by the Applied Nuclear Physics group of the Londrina State University - Applied Nuclear Physics Laboratory - Brazil, from the activities beginning (1977) up to the end of the year 1997.

  17. The Effects of Applying Organic Matter in Wind Blown Soil on Microbial Biomass and Enzyme Activity

    2003-01-01

    Field experiment was conducted to study the effect of applying organic matter in wind blown soil on microbial biomass and enzyme activity.The results showed that microbial biomass and enzyme activity keep dynamic changes during wheat growing season in wind blown soil,and reached the peak level in wheat booting stage.Compared with chemical fertilizer,all the other treatments could increase the microbial biomass in different degree,the same as catalsae and alkaline phosphatase activity,But urease activity was slightly difference from them.

  18. Development of seismic support snubber using solid lubricant

    Solid lubricant MoS2 films deposited by radio-frequency sputtering and a new physical process were applied to bearings and ball screws used in seismic support mechanical snubbers. The lubricity of MoS2 films was maintained throughout 720 hours of exposure at a temperature of 200 degC. The endurance life of MoS2 films using both radio-frequency sputtering and a new physical process was investigated by subjecting the mechanical snubber to a drag force test. Cumulative drag length reached 100 meters and 400 meters, respectively, for the two methods. The dynamic characteristics and durability of mechanical snubbers in an abnormal environment were also investigated. (author)

  19. Ordered molecular layer structure of lubricating oil adsorbed films

    2001-01-01

    Low-angle X-ray diffraction has been applied to analyze the structure of stearic acid LB films and self-grown surface adsorbed films of aluminium product metalworking lubricants. The results show that LB films exhibit a good layer-like ordered structure in the normal direction of film-carrying surface, while in the tangential direction, they do not show a cyclically ordered molecular arrangement; as for the self-grown surface adsorbed films of aluminium sheet and strip metalworking lubricants, their molecules are orderly arranged to certain degree in both the tangential and the normal directions of film-carrying surface, and they have a short-range ordered structure. Moreover, the better the orientation of normal molecules is, the higher the oil film strength is, and the smaller the friction factor is.

  20. New lubricating material for hydraulic turbine generators

    The current state-of-the-art of lubricating practices for major hydraulic equipment which is in contact with water, such as wicket gates, were surveyed by the Canadian Electrical Association by means of a questionnaire. Participants in the survey included owners and operators, designers and bearing and lubricant suppliers. Current practices, major technical issues and potential constraints of using alternative, environmentally friendly lubricant practices were identified. It was found that self lubricating bearing materials were commonly used to address environmental concerns. Results of the survey also revealed that regulations for underwater hydraulic equipment have not been established in Canada nor the U.S. Several recommendations for adopting environmentally friendly lubricants into current practices were made

  1. Biodegradation and toxicological evaluation of lubricant oils

    Ivo Shodji Tamada

    2012-12-01

    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.

  2. Simulations of modal active control applied to the self-sustained oscillations of the clarinet

    Meurisse, Thibaut; MAMOU-MANI, Adrien; Caussé, René; SHARP, David

    2013-01-01

    Modal active control enables modifications of the damping and the frequencies of the different resonances of a system. A self-sustained oscillating wind instrument is modelled as a disturbance coupled to a resonator through a non-linear coupling. The aim of this study is to present simulations of modal active control applied to a modeled simplified self-sustained oscillating wind instrument (e.g. a cylindrical tube coupled to a reed, which is considered to approximate a simplified clarinet), ...

  3. When you lubricate well, you go well? A cause analysis of damages on bearer rings at a hydrogen compressor recently brought into service with the aid of monitoring the lubricating points of cylinder liners; Wer gut schmiert, der gut faehrt? Ursachenanalyse an Tragringschaeden bei einem neu in Betrieb genommenen Wasserstoffverdichter mit Hilfe einer Zylinderschmierstellenueberwachung

    Klinger, Lars [Bayernoil Raffineriegesellschaft mbH, Neustadt a.d. Donau (Germany)

    2013-02-15

    For humans the blood circuit transports the ''lifeblood''. It supplies the body with the different essential nutrients and disposes adverse waste. The circuit of lubricant in recip compressors has quiet similar functions. It provides all relevant components with lubricant. This lubricant circuit supplies i.a. the crosshead slide way and bearings, where a hydrodynamic flooding is created. At the same time frictional heat is conducted and pollutions as well as deposits are washed away. But especially for recip compressors there is also another lubricating system, which is barely applied in the real operating process. It is about the supply of the packing glands and the piston liners with lubricant inside the compression chamber at ''wet running machines''. In the case of the lubricant supply at cylinder liners the lubricating oil is dispatched to the appropriate areas by an external lubricating system, which consists of a reservoir and an oil pump. This is a loss lubrication, i.e. the used lubricate is transported into the process by the transfer medium. The mechanical quality of this lubricating system can have great influence on the durability of bearer rings and sealing rings in a recip compressor. Especially the homogeneity of the dispatched lubricating oil amount and the absolute dispatched amount are two very important factors. The absolute amount is within the range of cm{sup 3} per hour. The influences of the cylinder liner lubricant supply on the durability of piston seal rings and bearer rings are shown with the concrete example of one recip compressor. Analytical measures to clearly detect such damages at the bearer rings are disclosed, just as which possibility there is to measure the low quantity of lubricant to the cylinder liners reliably. Furthermore a solution is presented, which allows the solid operation of the compressor.

  4. 24 CFR 1000.242 - When does the requirement for exemption from taxation apply to affordable housing activities?

    2010-04-01

    ... exemption from taxation apply to affordable housing activities? 1000.242 Section 1000.242 Housing and Urban... ACTIVITIES Indian Housing Plan (IHP) § 1000.242 When does the requirement for exemption from taxation apply to affordable housing activities? The requirement for exemption from taxation applies only to...

  5. Squeezing Molecularly thin Lubricant Films between curved Corrugated Surfaces with long range Elasticity

    Sivebæk, Ion Marius; Samoilov, Vladimir N.; Persson, Bo N. J.

    2010-01-01

    The present work investigates the ability of two nm thick lubrication films to stay in a contact and thereby to prevent excessive wear of the surfaces. At this thickness the film is no longer a fluid but it is the very important intermediate between the lubricated and the dry regimes, the latter...... one being associated with devastating wear progress. The properties of alkane lubricants confined between two approaching solids are investigated by a model that accounts for the roughness, curvature and elastic properties of the solid surfaces. We consider linear alkanes of different chain lengths, C......3H8, C4H10, C8H18, C9H20, C10H22, C14H30 and C16H34, confined between corrugated gold surfaces. Well defined molecular layers develop in the lubricant film when the width is of the order of a few atomic diameters. An external squeezing pressure induces discontinuous, thermally activated changes in...

  6. Recent activities of Applied Laser Technology Institute at Tsuruga Head Office of JAEA

    The Applied Laser Technology Institute(ALTI) was established in the Tsuruga headquarters of Japan Atomic Energy Agency (JAEA) in Fukui prefecture in September, 2009. The objectives of the ALTI are the contribution of the laser technology to the nuclear power technology as well as industrial applications. The latest activity of the ALTI is introduced here. (author)

  7. Recent activities of Applied Laser Technology Institute at Tsuruga Head Office of JAEA

    The Applied Laser Technology Institute (ALTI) was established in the Tsuruga headquarters of Japan Atomic Energy Agency (JAEA) in Fukui prefecture in September, 2009. The objectives of the ALTI are the contribution of the laser technology to the nuclear power technology as well as industrial applications. The latest activity of the ALTI is introduced here. (author)

  8. 6 CFR Appendix A to Part 21 - Activities to Which This Part Applies

    2010-01-01

    ... FINANCIAL ASSISTANCE FROM THE DEPARTMENT OF HOMELAND SECURITY Pt. 21, App. A Appendix A to Part 21... 6 Domestic Security 1 2010-01-01 2010-01-01 false Activities to Which This Part Applies A Appendix A to Part 21 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE...

  9. Theoretical analysis and experimental study on the influence of electric double layer on thin film lubrication

    WANG Xin-jie; BAI Shao-xian; HUANG Ping

    2006-01-01

    A new mathematical model for thin film lubrication is established by taking into account the effect of an electric double layer.In the present paper,experiments are carried out on a self-made tester.With a composite block and a rotating disk,influence of electric double layer on thin film lubrication is studied.Two different methods are used to reconstruct the field of electric double layer so as to change its effect.One is to change the ionic concentration of lubricants by adding additives,and the other is to apply an external electric field on friction pairs.According theoretical analysis,both the methods will apparently change the electro-viscosity of the lubricant film so as to change the lubrication performances.After theoretical calculation of electro-viscosity is amended according to the experimental results,the equations of electro-viscosity are presented.The results show that the equivalent viscosity of fluid induced by the effect of electric double layer apparently increases with the decrease of thickness of the film while the lubrication film is thin enough.The effect of electro-viscosity is weakened as the thickness of the film increases.Moreover,the effect of electro-viscosity increases with the increase of external electric field at first.When the voltage reaches a certain value,the electro-viscosity begins to decrease.

  10. 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.

  11. Wide-temperature-spectrum self-lubricating coatings prepared by plasma spraying

    Sliney, H. E.

    1979-01-01

    Self-lubricating, multicomponent coatings, which lubricate over a wide range of operating conditions, are described. The coatings have been successfully applied by plasma-spraying mixed powders onto superalloy substrates. They have been evaluated in friction and wear experiments, and in sliding contact bearing tests. These coatings are wear resistant by virtue of their self-lubricating characteristics rather than because of extreme hardness; a further benefit is low friction. Experiments with simple pin on disk sliding specimens and oscillating plain cylindrical bearing tests were performed to evaluate the tribological properties of the coatings. It was shown that coatings of nichrome, glass and calcium fluoride are self-lubricating from about 500 to 900 C, but give high friction at the lower temperatures. The addition of silver to the coating composition improved the low temperature bearing properties and resulted in coatings which are self-lubricating from cryogenic temperatures to at least 870 C; they are therefore 'wide temperature spectrum,' self-lubricating compositions.

  12. Characterization of used lubricating oil by spectrometric techniques

    Souza, Andressa Moreira de, E-mail: andressa@ctaa.embrapa.br [Embrapa Agroindustria de Alimentos, Guaratiba, Rio de Janeiro, RJ (Brazil); Correa, Sergio Machado [Faculdade de Engenharia. Universidade do Estado do Rio de Janeiro (UERJ), Resende, RJ (Brazil); Silva, Glauco Correa da [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    Full text: The engine lubricating oil drags all kinds of impurities generated by wear of internal components. Thus, it is necessary to monitor the physical and chemical properties and concentration of metals in lubricants used to determine the appropriate time to replace them. Moreover, one can monitor the wear of the engines through the levels of metals in oils. To achieve these goals, some detection techniques such as Flame atomic absorption spectrometry (FAAS), Inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray fluorescence (XRF), have been widely used to determine metals in lubricating oils and also in other oil derivatives. Thus, some of these techniques were used in this study. Also the technique used was Gas chromatography mass spectrometry (GC / MS) for characterization of chromatographic profile of the engine lubricating oil after use. Through the technique of ICP-OES for method of United States Environmental Protection Agency (USEPA) METHOD 6010B - Inductively coupled plasma optical emission spectrometry was performed to characterize metals in lubricating oil motor, using equipment from ICP-OES Perkin-Elmer{sup R} OPTIMA 3000 ICP-Winlab and software, obtaining the following identification of metals: barium (Ba), calcium (Ca), lead (Pb), copper (Cu), Chromium (Cr), iron (Fe), magnesium (Mg), molybdenum (Mo) and zinc (Zn). Using the XRF technique, through the equipment EDFRX Shimadzu{sup R} model 800HS EDX, Rh tube, applied voltage of 50kV, amperage 100{mu}A, detector Si (Li) cooled with liquid nitrogen and collimator 10mm, we analyzed all the components comprised in the range of Ti to U and Na to SC, identified the following metals: calcium (Ca), zinc (Zn), iron (Fe), copper (Cu), molybdenum (Mo) and nickel (Ni). The characterization was performed by chromatographic methods: USEPA METHOD 5021A - Volatile organic compounds in various sample matrices using equilibrium headspace analysis, USEPA METHOD 8015B - Nonhalogenated Organics

  13. Characterization of used lubricating oil by spectrometric techniques

    Full text: The engine lubricating oil drags all kinds of impurities generated by wear of internal components. Thus, it is necessary to monitor the physical and chemical properties and concentration of metals in lubricants used to determine the appropriate time to replace them. Moreover, one can monitor the wear of the engines through the levels of metals in oils. To achieve these goals, some detection techniques such as Flame atomic absorption spectrometry (FAAS), Inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray fluorescence (XRF), have been widely used to determine metals in lubricating oils and also in other oil derivatives. Thus, some of these techniques were used in this study. Also the technique used was Gas chromatography mass spectrometry (GC / MS) for characterization of chromatographic profile of the engine lubricating oil after use. Through the technique of ICP-OES for method of United States Environmental Protection Agency (USEPA) METHOD 6010B - Inductively coupled plasma optical emission spectrometry was performed to characterize metals in lubricating oil motor, using equipment from ICP-OES Perkin-ElmerR OPTIMA 3000 ICP-Winlab and software, obtaining the following identification of metals: barium (Ba), calcium (Ca), lead (Pb), copper (Cu), Chromium (Cr), iron (Fe), magnesium (Mg), molybdenum (Mo) and zinc (Zn). Using the XRF technique, through the equipment EDFRX ShimadzuR model 800HS EDX, Rh tube, applied voltage of 50kV, amperage 100μA, detector Si (Li) cooled with liquid nitrogen and collimator 10mm, we analyzed all the components comprised in the range of Ti to U and Na to SC, identified the following metals: calcium (Ca), zinc (Zn), iron (Fe), copper (Cu), molybdenum (Mo) and nickel (Ni). The characterization was performed by chromatographic methods: USEPA METHOD 5021A - Volatile organic compounds in various sample matrices using equilibrium headspace analysis, USEPA METHOD 8015B - Nonhalogenated Organics Using GC

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

    Ginosar, Daniel M.; Fox, Robert V.

    2005-05-03

    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.

  15. Evaluation on activation activity of reactor in JRR-2 applied 3 dimensional model to neutron flux calculation

    Revaluation to activation activity of reactor evaluated at the notification of dismantling submitted in 1997 was carried out in JRR-2 where decommissioning was advanced now. In the revaluation, estimation accuracy on neutron streaming at various horizontal experimental tubes was improved by applying 3 dimensional model to neutron transport calculation that had been carried out by 2 dimensional model, and calculating with TORT. As the result, excessive overestimations on horizontal experimental tubes and biological shield that had greatly contributed to total activation activity in evaluation at the notification of dismantling was revised, sum of their activation activities in the revaluation decreased to 1/18 (case after 1 year from the permanent shutdown of reactor) of evaluation at the notification of dismantling, and the structural materials that had large activation activity were changed. By the above, it was shown that introducing 3 dimensional model was effective in evaluation on activation activity of the research reactor that had a lot of various experimental tubes. Total activation activity of reactor by the revaluation depended on control rods, thermal shield plates and horizontal experimental tubes, and the value after 1 year from the permanent shutdown of reactor was 1.9x1014 Bq. (author)

  16. Application of a Biodegradable Lubricant in a Diesel Vehicle

    Schramm, Jesper

    2003-01-01

    , 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. Friction Regimes in the Lubricants Solid-State Regime

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

    1995-01-01

    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

  18. National youth sedentary behavior and physical activity daily patterns using latent class analysis applied to accelerometry

    Evenson, Kelly R.; Wen, Fang; Hales, Derek; Herring, Amy H.

    2016-01-01

    Background Applying latent class analysis (LCA) to accelerometry can help elucidated underlying patterns. This study described the patterns of accelerometer-determined sedentary behavior and physical activity among youth by applying LCA to a nationally representative United States (US) sample. Methods Using 2003–2006 National Health and Nutrition Examination Survey data, 3998 youths 6–17 years wore an ActiGraph 7164 accelerometer for one week, providing > =3 days of wear for > =8 h/day from 6...

  19. Determining the Thermal Properties of Space Lubricants

    Maldonado, Christina M.

    2004-01-01

    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.

  20. An integrated lubricant oil conditioning sensor using signal multiplexing

    One effective approach to detect signs of potential failure of a rotating or reciprocating machine is to examine the conditions of its lubrication oil. Here we present an integrated oil condition sensor for detecting both wear debris and lubricant properties. The integrated sensor consists of miniature multiplexed sensing elements for detection of wear debris and measurements of viscosity and moisture. The oil debris sensing element consists of eight sensing channels to detect wear debris in parallel; the elements for measuring oil viscosity and moisture, based on interdigital electrode sensing, were fabricated using micromachining. The integrated sensor was installed and tested in a laboratory lubricating system. Signal multiplexing was applied to the outputs of the three sensing elements such that responses from all sensing elements were obtained within two measurements, and the signal-to-noise ratio was improved. Testing results show that the integrated sensor is capable of measuring wear debris (>50 µm), moisture (>50 ppm) and viscosity (>12.4 cSt) at a high throughput (200 ml min−1). The device can be potentially used for online health monitoring of rotating machines. (paper)

  1. Immobilisation of alpha contaminated lubricating oils in cement matrix

    Alpha contaminated lubricating oil wastes are generated from the reprocessing plants and other alpha handling facilities. Incineration of these spent lubricating oils requires specially designed facility to handle the aerosols of actinide oxides released to the off-gases. Hence immobilisation of these wastes into cement matrix could be a viable alternative. Work was therefore initiated to examine the possibility of immobilising such waste in cement matrix with the help of suitable additives. This work led to the selection of sodium hydroxide and silica fumes as additives for their distinct role in immobilization of such waste in cement. The selected formulation was tested extensively both on laboratory scale and full scale for acceptable waste form. The leach test on laboratory scale indicated negligible release of alpha and beta gamma activity after 180 days. This report gives a brief on the formulation of the admixture and its effect on the immobilization of waste. (author)

  2. Potential of Palm Olein as Green Lubricant Source: Lubrication Analysis and Chemical Characterisation

    Palm olein (POo) is widely used as edible oil in tropical countries. The lubrication properties and chemical compositions of POo being considered to be used as renewable raw material for bio lubricant synthesis. POo is suitable to be used directly as bio lubricant for medium temperature industrial applications. Palm olein has good viscosity index, oxidative stability, flash and fire point as a lubricant source. POo contains unsaturated triacylglycerols (TAG): Palmitin-Olein-Olein, POO (33.3 %), Palmitin-Olein-Palmitin, POP (29.6 %), which are very important to produce good lubricant properties. This unsaturated bond is preferable in chemical modification to produce bio lubricant. The chemical compositions of POo were tested by using high performance liquid chromatography (HPLC) and gas chromatography (GC) techniques. (author)

  3. The role of lubricant analysis in maximizing lubricant and equipment life

    Lubricant analysis has always played an important yet somewhat invisible role in equipment health monitoring. At its most primitive, simple observations and field testing alert equipment operators to changing conditions. At its most advanced, data from performance and analytical tests are used to develop or select optimum lubricants for service, stretch drain intervals, predict remaining equipment life and identify potential equipment or system problems at an incipient stage. Coupled with thermography and vibration analysis, lubricant analysis can become a major component of a comprehensive predictive maintenance (PM) program. Ontario Hydro finds itself at a turning point regarding the use and monitoring of lubricants. Increasing emphasis on equipment reliability and plant life extension, coupled with major, recent changes in lubricant composition in response to environmental, energy and safety concerns, forces an upgrading of many aspects of lubricant monitoring so that it may establish itself as a key part of modern PM practices. This paper discusses some of these aspects. (author)

  4. Graphite and Hybrid Nanomaterials as Lubricant Additives

    Zhenyu J. Zhang

    2014-04-01

    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.

  5. Lubrication Influence on Wear Evolution of Xylan 1052 Coated Disk Tested at Various Rotational Speed and High Contact Stress

    Ion-Cornel Mituletu

    2013-05-01

    Full Text Available This paper relates the lubrication influence on the Xylan 1052 coating applied as the surface layer of a testing disk. By pressing a coated and uncoated bearing ball against the surface of coated disk having different rotational speeds, wear evolution diagrams have been achieved. Tests were performed in three specific conditions, when the disk coated surface is: dry, under poor or continuous lubrication. These conditions allow understanding the influence of poor or continuous lubrication on the behavior of coated disk surface at the contact stress. Such conditions could practically occur due to some problems appearing in industrial environment.

  6. PetroChina Continues to Restructure Lubricants Assets

    Zhang Bingxing

    2002-01-01

    @@ 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.

  7. Developments and unsolved problems in nano-lubrication*

    2001-01-01

    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.

  8. Device for lubricating sealed support of a cutter bit

    Grushkin, B.N.; Balabashin, B.P.; Popov, L.N.; Spivak, A.I.; Yudin, A.S.; Zhulayev, V.P.

    1982-01-01

    A device is proposed for lubricating the sealed support of a cutter bit. It contains a vessel arranged in the bit clamp for supplying the lubricant material, a pump with piston and a closed system of lubricant-supplying channels. In order to improve the efficiency of lubrication during drilling with above-bit shock absorbers by accelerating the circulation of the lubricating material, the pump piston is installed with the potential of interacting with the shock absorber.

  9. Upgrading the lubricity of bio-oil via homogeneous catalytic esterification under vacuum distillation conditions

    In order to accelerate the application of bio-oil in the internal combustion engines, homogeneous catalytic esterification technology under vacuum distillation conditions was used to upgrade the crude bio-oil. The lubricities of the crude bio-oil (BO) and refined bio-oil with homogeneous catalytic esterification (RBOhce) or refined bio-oil without catalyst but with distillation operation (RBOwc) were evaluated by a high frequency reciprocating test rig according to the ASTM D 6079 standard. The basic physiochemical properties and components of the bio-oils were analyzed. The surface morphology, contents and chemical valence of active elements on the worn surfaces were investigated by scanning electron microscopy, energy dispersive spectroscopy and X-ray photoelectron spectroscopy, respectively. The results show that RBOhce has better lubricities than those of BO, but RBOwc has worse lubricities than those of BO. The tribological mechanisms of the bio-oils are attributed to the combined actions of lubricating films and factors that will break the film. Compared with BO, plenty of phenols in RBOwc results in corrosion of the substrate and destroys the integrity of the lubricating films, which is responsible for its corrosive wear. However, more esters and alkanes in RBOhce contribute to forming a complete boundary lubricating film on the rubbed surfaces which result in its excellent antifriction and antiwear properties. - Highlights: • Refined bio-oil was prepared through homogeneous catalytic esterification technology. • Properties of the bio-oils before and after refining were assessed by HFRR. • Refined bio-oil showed better lubricities than crude bio-oil. • More esters and alkanes in refined bio-oil contributed to forming superior boundary lubrication

  10. A randomized controlled trial comparing nonoxynol-9 lubricated condoms with silicone lubricated condoms for prophylaxis

    Roddy, R E; M. Cordero; Ryan, K.A.; Figueroa, J.

    1998-01-01

    OBJECTIVE: We tested the effect of nonoxynol-9 (N-9) in condom lubrication on the risk of acquiring STD and genital discomfort. METHODS: The study was a triple masked, randomised controlled trial comparing N-9 lubricated condoms with plain silicone lubricated condoms among Dominican female sex workers. RESULTS: Randomisation provided two groups (313 for N-9 and 322 for plain) similar in baseline characteristics, but extensive loss to follow up occurred (56 women in each group completed ...