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Sample records for actively lubricated journal

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Tribology experiment. [journal bearings and liquid lubricants

    NASA Technical Reports Server (NTRS)

    Wall, W. A.

    1981-01-01

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

  3. Mixed Lubrication Analysis for Journal Bearings in Rotary Compressors

    NASA Astrophysics Data System (ADS)

    Hattori, Hitoshi; Ito, Yasutaka; Hirayama, Takuya; Miura, Kazuhiko

    This paper describes the numerical analysis of mixed lubrication and the calculated results for journal bearings in rotary compressors. In this analysis, the modified Reynolds equation and the elastic contact equation, considering the effect of surface roughness, are solved as a coupled problem, and then influences of the elastic deformation of the bearing surface and the motion of the rotating shaft with bending deformation are also considered. The appearance of solid contact in hydrodynamic lubrication can be addressed by the analysis. Influences of the rotating speed and the surface roughness on the lubrication characteristics of the journal bearing were investigated by using the mixed lubrication analysis. As the results, it is made clear that the solid contact on the bearing surface occurs in the discharge process of rotary compressors. Furthermore, the contact pressure and the contact area decrease, even though the oil film thickness decreases, when the surface roughness becomes small.

  4. 49 CFR 215.109 - Defective plain bearing box: Journal lubrication system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Defective plain bearing box: Journal lubrication... Freight Car Components Suspension System § 215.109 Defective plain bearing box: Journal lubrication system...) Metal parts contacting the journal; or (e) Is— (1) Missing; or (2) Not in contact with the journal....

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

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Defective plain bearing box: Journal lubrication... Freight Car Components Suspension System § 215.109 Defective plain bearing box: Journal lubrication system...) Metal parts contacting the journal; or (e) Is— (1) Missing; or (2) Not in contact with the journal....

  6. 49 CFR 215.109 - Defective plain bearing box: Journal lubrication system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Defective plain bearing box: Journal lubrication... Freight Car Components Suspension System § 215.109 Defective plain bearing box: Journal lubrication system...) Metal parts contacting the journal; or (e) Is— (1) Missing; or (2) Not in contact with the journal....

  7. 49 CFR 215.109 - Defective plain bearing box: Journal lubrication system.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Defective plain bearing box: Journal lubrication... Freight Car Components Suspension System § 215.109 Defective plain bearing box: Journal lubrication system...) Metal parts contacting the journal; or (e) Is— (1) Missing; or (2) Not in contact with the journal....

  8. 49 CFR 215.109 - Defective plain bearing box: Journal lubrication system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  9. Static Characteristics of Conical Hydrostatic Journal Bearing Under Micropolar Lubrication

    NASA Astrophysics Data System (ADS)

    Rana, N. K.; Gautam, S. S.; Verma, S.

    2014-08-01

    A theoretical analysis for static characteristics of a conical hydrostatic journal bearing for a multirecess constant flow valve compensated under micropolar lubrication has been carried out in this work. The numerical solution of the modified Reynolds equation for the conical bearing has been done using Finite Element Method (FEM) using necessary boundary conditions. The various static characteristics have been presented to analyze the performance of bearing at zero speed.

  10. Static Characteristics of Conical Hydrostatic Journal Bearing Under Micropolar Lubrication

    NASA Astrophysics Data System (ADS)

    Rana, N. K.; Gautam, S. S.; Verma, S.

    2014-10-01

    A theoretical analysis for static characteristics of a conical hydrostatic journal bearing for a multirecess constant flow valve compensated under micropolar lubrication has been carried out in this work. The numerical solution of the modified Reynolds equation for the conical bearing has been done using Finite Element Method (FEM) using necessary boundary conditions. The various static characteristics have been presented to analyze the performance of bearing at zero speed.

  11. Hydrodynamic journal bearings: Capacity, wear, and lubrication. (Latest citations from Fluidex data base). Published Search

    SciTech Connect

    Not Available

    1992-08-01

    The bibliography contains citations concerning the characteristics of hydrodynamic journal bearings. Bearing load, lubrication, thermal effects, tolerance to misalignment, cavitation, and design are discussed. Studies on the effect of temperature and heat transfer on hydrodynamic films are presented. The impact of surface roughness on hydrodynamic journal bearing performance is also examined. (Contains 250 citations and includes a subject term index and title list.)

  12. Steady State Performance Characteristics of Micropolar Lubricated Hydrodynamic Journal Bearings with Flexible Liner

    NASA Astrophysics Data System (ADS)

    Bansal, Pikesh; Chattopadhyay, Ajit Kumar; Agrawal, Vishnu Prakash

    2016-04-01

    The aim of the present study is to theoretically determine the steady state characteristics of hydrodynamic oil journal bearings considering the effect of deformation of liner and with micropolar lubrication. Modified Reynolds equation based on micropolar lubrication theory is solved using finite difference method to obtain steady state film pressures. Minimum film thickness is calculated taking into consideration the deformation of the liner. Parametric study has been conducted and steady state characteristics for journal bearing with elasticity of bearing liner are plotted for various values of eccentricity ratio, deformation factor, characteristic length and coupling number.

  13. Dynamic analysis of liquid-lubricated hydrostatic journal bearings

    SciTech Connect

    Kocur, J.A. Jr.

    1990-01-01

    A hybrid bearing reduces the dependency of its behavior on the lubricant viscosity, bearing clearance, bearing surface area by combining the hydrostatic and hydrodynamic effects. The combination permits the hybrid bearing to be incorporated into rotor designs, where the working fluids of the rotor may be used in place of externally supplied lubricants. An effective and practical method to predict the static and dynamic behavior of hybrid bearings is developed. The model includes the three major fluid effects in the bearing; the orifice restriction, inertia losses at the pocket edges, and hydrodynamic effects on the bearing land regions. Lubrication is modeled and calculated using a finite element solution of Reynolds equation with turbulence corrections.

  14. Bifurcation and chaos analysis of nonlinear rotor system with axial-grooved gas-lubricated journal bearing support

    NASA Astrophysics Data System (ADS)

    Zhang, Yongfang; Hei, Di; Lü, Yanjun; Wang, Quandai; Müller, Norbert

    2014-03-01

    Axial-grooved gas-lubricated journal bearings have been widely applied to precision instrument due to their high accuracy, low friction, low noise and high stability. The rotor system with axial-grooved gas-lubricated journal bearing support is a typical nonlinear dynamic system. The nonlinear analysis measures have to be adopted to analyze the behaviors of the axial-grooved gas-lubricated journal bearing-rotor nonlinear system as the linear analysis measures fail. The bifurcation and chaos of nonlinear rotor system with three axial-grooved gas-lubricated journal bearing support are investigated by nonlinear dynamics theory. A time-dependent mathematical model is established to describe the pressure distribution in the axial-grooved compressible gas-lubricated journal bearing. The time-dependent compressible gas-lubricated Reynolds equation is solved by the differential transformation method. The gyroscopic effect of the rotor supported by gas-lubricated journal bearing with three axial grooves is taken into consideration in the model of the system, and the dynamic equation of motion is calculated by the modified Wilson- θ-based method. To analyze the unbalanced responses of the rotor system supported by finite length gas-lubricated journal bearings, such as bifurcation and chaos, the bifurcation diagram, the orbit diagram, the Poincaré map, the time series and the frequency spectrum are employed. The numerical results reveal that the nonlinear gas film forces have a significant influence on the stability of rotor system and there are the rich nonlinear phenomena, such as the periodic, period-doubling, quasi-periodic, period-4 and chaotic motion, and so on. The proposed models and numerical results can provide a theoretical direction to the design of axial-grooved gas-lubricated journal bearing-rotor system.

  15. Prediction of Gas Lubricated Foil Journal Bearing Performance

    NASA Technical Reports Server (NTRS)

    Carpino, Marc; Talmage, Gita

    2003-01-01

    This report summarizes the progress in the first eight months of the project. The objectives of this research project are to theoretically predict the steady operating conditions and the rotor dynamic coefficients of gas foil journal bearings. The project is currently on or ahead of schedule with the development of a finite element code that predicts steady bearing performance characteristics such as film thickness, pressure, load, and drag. Graphical results for a typical bearing are presented in the report. Project plans for the next year are discussed.

  16. On the performance of finite journal bearings lubricated with micropolar fluids

    NASA Technical Reports Server (NTRS)

    Khonsari, M. M.; Brewe, D. E.

    1988-01-01

    A study of the performance parameters for a journal bearing of finite length lubricated with micropolar fluids is undertaken. Results indicate that a significantly higher load carrying capacity than the Newtonian fluids may result depending on the size of material characteristic length and the coupling number. It is also shown that although the frictional force associated with micropolar fluid is in general higher than that of a Newtonian fluid, the friction coefficient of micropolar fluids tends to be lower than that of the Newtonian.

  17. Hydrodynamic air lubricated compliant surface bearing for an automotive gas turbine engine. 1: Journal bearing performance

    NASA Technical Reports Server (NTRS)

    Ruscitto, D.; Mccormick, J.; Gray, S.

    1978-01-01

    A 38.1 mm (1.5 inch) diameter Hydresil Compliant Surface Air Lubricated Journal Bearing was designed and tested to obtain bearing performance characteristics at both room temperature and 315 C (600 F). Testing was performed at various speeds up to 60,000 rpm with varying loads. Rotating sensors provided an opportunity to examine the film characteristics of the compliant surface bearing. In addition to providing minimum film thickness values and profiles, many other insights into bearing operation were gained such as the influence of bearing fabrication accuracy and the influence of smooth foil deflection between the bumps.

  18. Development of surface coatings for air-lubricated, compliant journal bearings to 650 C

    NASA Technical Reports Server (NTRS)

    Bhushan, B.; Gray, S.

    1978-01-01

    Surface coatings for an air-lubricated, compliant journal for an automotive gas turbine engine were tested to find those capable of withstanding temperatures of either 540 C (1000 F) or 650 C (1200 F). Also, the coatings have to be capable of surviving the start-stop sliding contact cycles prior to rotor lift-off and at touchdown. Selected coating combinations were tested in start-stop tests at 14 kPa (2 psi) loading for 2000 cycles at room and maximum temperatures. Specific coating recommendations are: Cdo and graphite on foil versus chrome carbide on journal up to 370 C (700 F); NASA PS-120 (Tribaloy 400, silver, and CaF2) on journal versus uncoated foil up to 540 C (1000 F); and chemically adherent Cr2O3 on journal and foil up to 650 C (1200 F). The chemically adherent Cr2O3 coating system was further tested successfully at 35 kPa (5 psi) loading for 2000 start-stop cycles.

  19. Effect of Elasticity on Capillary Compensated Flexible Multi-recess Hydrostatic Journal Bearing Operating with Micropolar Lubricant

    NASA Astrophysics Data System (ADS)

    Verma, Suresh; Kumar, Vijay; Gupta, Kapil Dev

    2016-01-01

    This paper presents a theoretical study of the effects of bearing shell deformation upon the performance characteristics of a capillary compensated multi-recess hydrostatic journal bearing system operating with micropolar lubricant. The finite element method has been used to solve the modified Reynolds' equation governing the micropolar lubricant flow in the bearing and the three dimensional elasticity equations governing the displacement field in the bearing shell. The elasto-hydrostatic performance characteristics of the bearing are presented for various values of micropolar parameters ( l m and N 2) and for a wide range of the deformation coefficient bar{C}d which takes into account the flexibility of the bearing shell. The computed results indicate that the influence of the bearing shell flexibility is quite significant on the performance characteristics of recessed hydrostatic journal bearing system operating with micropolar lubricant.

  20. Design of various fixed-geometry water-lubricated hydrodynamic journal bearings for maximum stability

    NASA Technical Reports Server (NTRS)

    Schuller, F. T.

    1973-01-01

    This publication is the result of over 260 fractional-frequency-whirl stability tests on a variety of fixed-geometry journal bearings. It is intended principally as a guide in the selection and design of antiwhirl bearings that must operate at high speeds and low loads in low-viscosity fluids such as water or liquid metals. However, the various fixed-geometry configurations can be employed as well in applications where other lubricants, such as oil, are used and fractional-frequency whirl is a problem. The important parameters that effect stability are discussed for each bearing type, and design curves to facilitate the design of optimum-geometry bearings are included. A comparison of the stability of the different bearing configurations tested is also given.

  1. Laser-optical and numerical Research of the flow inside the lubricating gap of a journal bearing model

    NASA Astrophysics Data System (ADS)

    Nobis, M.; Stücke, P.; Schmidt, M.; Riedel, M.

    2013-04-01

    The laser-optical research of the flow inside the lubricating gap of a journal bearing model is one important task in a larger overall project. The long-term objective is the development of an easy-to-work calculation tool which delivers information about the causes and consequences of cavitation processes in hydrodynamically lubricated journal bearings. Hence, it will be possible to find statements for advantageous and disadvantageous geometrical shapes of the bushings. In conclusion such a calculation tool can provide important insights for the construction and design of future journal bearings. Current design programs are based on a two-dimensional approach for the lubricating gap. The first dimension is the breath of the bearing and the second dimension is the circumferential direction of the bearing. The third dimension, the expansion of the gap in radial direction, will be neglected. Instead of an exact resolution of the flow pattern inside the gap, turbulence models are in use. Past studies on numerical and experimental field have shown that inside the lubricating gap clearly organized and predominantly laminar flow structures can be found. Thus, for a detailed analysis of the reasons and effects of cavitation bubbles, a three-dimensional resolution of the lubricating gap is inevitable. In addition to the qualitative evaluation of the flow with visualization experiments it is possible to perform angle-based velocity measurements inside the gap with the help of a triggered Laser-Doppler- Velocimeter (LDV). The results of these measurements are used to validate three-dimensional CFD flow simulations, and to optimize the numerical mesh structure and the boundary conditions. This paper will present the experimental setup of the bearing model, some exemplary results of the visualization experiments and LDV measurements as well as a comparison between experimental and numerical results.

  2. Visual Journaling: Engaging Adolescents in Sketchbook Activities

    ERIC Educational Resources Information Center

    Cummings, Karen L.

    2011-01-01

    A wonderful way to engage high-school students in sketchbook activities is to have them create journals that combine images with words to convey emotions, ideas, and understandings. Visual journaling is a creative way for them to share their experiences and personal responses to life's events in visual and written form. Through selecting and…

  3. Stability of water-lubricated three-lobe journals mated with plain bearings at zero load

    NASA Technical Reports Server (NTRS)

    Schuller, F. T.

    1972-01-01

    Tests were conducted with plain bearings running with three types of three-lobe journals. The bearings, with a nominal 3.8-centimeter (1.5-in.) diameter and L/D of 1, were tested at 300 K (80 F) under stable conditions to 5400 rpm. The lobed configurations tested, in order of diminishing stability, were a tilted-lobe journal with grooves, a tilted-lobe journal without grooves, and a centrally lobed journal without grooves. A previously tested three-tilted-lobe bearing with grooves, running with a plain journal, was somewhat more stable than the tilted-lobe or centrally lobed journals.

  4. Dispersants having antioxidant activity and lubricating compositions containing them

    SciTech Connect

    Crawford, J.; Hill, G. A.

    1981-02-03

    Lubricating oil additives having both dispersant and antioxidant activity, particularly useful for incorporation in two-stroke petrol engine lubricating oil compositions, are produced when a dispersant having free >n-h groups, E.G., a substituted succinimide, is reacted with an aldehyde and a compound having antioxidant activity containing in its molecular structure a group or groups capable of condensing with the aldehyde and >n-h groups present in the dispersant, thereby chemically bonding the compound to the dispersant. Representative antioxidants are mononuclear and polynuclear substituted phenols having at least one unsubstituted ortho- or para-position, E.G. 2,6-di-tert-butyl phenol and secondary aromatic amines. Typical reaction conditions are a temperature in the range 100* to 175/sup 0/C, and atmospheric pressure.

  5. Load-Induced Confinement Activates Diamond Lubrication by Water

    NASA Astrophysics Data System (ADS)

    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.

  6. Fluid film force control in lubricated journal bearings by means of a travelling wave generated with a piezoelectric actuators' system

    NASA Astrophysics Data System (ADS)

    Iula, Antonio; Lamberti, Nicola; Savoia, Alessandro; Caliano, Giosue

    2012-05-01

    In this work an experimental evaluation of the possiblity to influence and control the fluid film forces in the gap of a lubricated journal bearing by means of a rotating travelling wave is carried out. The travellig wave is generated by two power actuators opportunely positioned on the outer surface of the bearing and electrically driven with a phase shift of 90°. Each transducer is designed to work at the natural frequency of the radial nonaxisymmetrical mode 0-5 (23.6 kHz). Experimental results show that the travelling wave is capable to control the motion of an oil drop on the inner surface of the bearing and that it is capable to put in rotation a rotor layed on the drop oil via the viscous forces in the oil drop itself.

  7. Consideration of Alternate Working Fluid Properties in Gas Lubricated Foil Journal Bearings

    NASA Technical Reports Server (NTRS)

    Smith, Matthew J.

    2004-01-01

    The Oil-Free Turbomachinery Program at the NASA Glenn Research center is committed to, revolutionary improvements in performance, efficiency and reliability of turbomachinery propulsion systems. One of the key breakthroughs by which this goal is being achieved is the maturation of air lubricated foil bearing technology. Through experimental testing, foil bearings have demonstrated a variety of exceptional qualities that show them to have an important role in the future of rotordynamic lubrication. Most of the work done with foil bearings thus far has considered ambient air at atmospheric pressure as the working fluid or lubricating fluid in the bearing. However, special applications of oil-free technology require the use of air at non- standard ambient conditions or completely different working fluids altogether. The NASA Jupiter Icy Moon Orbiter program presents power generation needs far beyond that of any previous space exploration effort. The proposed spacecraft will require significant power generation to provide the propulsion necessary to reach the moons of Jupiter and navigate between them. Once there, extensive scientific research will be conducted that will also present significant power requirements. Such extreme needs require exploring a new method for power generation in space. A proposed solution involves a Brayton cycle nuclear fission reactor. The nature of this application requires reliable performance of all reactor components for many years of operation under demanding conditions. This includes the bearings which will be operating with an alternative working fluid that is a combination of Helium and Xenon gases commonly known as HeXe. This fluid has transport and thermal properties that vary significantly from that of air and the effect of these property differences on bearing performance must be considered. One of the most promising applications of oil-free technology is in aircraft turbine engines. Eliminating the oil supply systems from

  8. Performance of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped flexibly mounted spiral-groove thrust bearing

    NASA Technical Reports Server (NTRS)

    Ream, L. W.

    1974-01-01

    A test program was conducted to determine the performance characteristics of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped spiral-groove thrust bearing designed for the Brayton cycle rotating unit (BRU). Hydrostatic, hybrid (simultaneously hydrostatic and hydrodynamic), and hydrodynamic tests were conducted in argon gas at ambient pressure and temperature ranges representative of operation to the 10.5 kWe BRU power-generating level. Performance of the gas lubricated bearings is presented including hydrostatic gas flow rates, bearing clearances, bearing temperatures, and transient performance.

  9. Approximate Analysis of Dynamic Characteristics of Short Journal Bearings in Turbulent Micropolar Lubrication

    NASA Astrophysics Data System (ADS)

    Rana, N. K.; Gautam, S. S.; Samanta, S.

    2014-10-01

    An approximate analysis has been carried out for short journal bearing to determine the dynamic behavior under micropolar turbulent flow condition. In this analysis, the Constantinescu's turbulent shear coefficient has been considered, which was later proposed by Taylor and Dowson. For the calculation of dynamic pressures, the classical Reynolds equation has been modified to incorporate turbulence and micropolar fluid parameters. The analysis has been further extended to determine the mass and whirl parameters to analyze the stability of the bearing. The bearing is found to be more stable with increase in eccentricity with high speed and large Reynolds number.

  10. Experimental load capacity and power loss of herringbone grooved gas lubricated journal bearings.

    NASA Technical Reports Server (NTRS)

    Cunningham, R. E.; Fleming, D. P.; Anderson, W. J.

    1971-01-01

    Load capacity, attitude angle, and power loss were determined for 1-1/2-in.-diam herringbone grooved journal bearings operating in air to speeds of 60,000 rpm. Results showed that groove-to-ridge-clearance ratios of 2.0 to 2.4 give a greater load capacity than do ratios outside this optimum range. Agreement with a small-eccentricity pressure perturbation theory was good for groove-to-ridge-clearance ratios in the optimum range. Power loss, relative to that calculated for a plain bearing of the same dimensions, did not vary widely for the range of geometric variables used. Relative power loss generally increased with speed and was generally comparable to that for a plain bearing.

  11. Wave journal bearing with compressible lubricant--Part 1: The wave bearing concept and a comparison to the plain circular bearing

    NASA Technical Reports Server (NTRS)

    Dimofte, Florin

    1995-01-01

    To improve hydrodynamic journal bearing steady-state and dynamic performance, a new bearing concept, the wave journal bearing, was developed at the author's lab. This concept features a waved inner bearing diameter. Compared to other alternative bearing geometries used to improve bearing performance such as spiral or herring-bone grooves, steps, etc., the wave bearing's design is relatively simple and allows the shaft to rotate in either direction. A three-wave bearing operating with a compressible lubricant, i.e., gas is analyzed using a numerical code. Its performance is compared to a plain (truly) circular bearing over a broad range of bearing working parameters, e.g., bearing numbers from 0.01 to 100.

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

    PubMed

    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

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

    PubMed Central

    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

  14. Dynamic behavior of air lubricated pivoted-pad journal-bearing, rotor system. 2: Pivot consideration and pad mass

    NASA Technical Reports Server (NTRS)

    Nemeth, Z. N.

    1972-01-01

    Rotor bearing dynamic tests were conducted with tilting-pad journal bearings having three different pad masses and two different pivot geometries. The rotor was vertically mounted and supported by two three-pad tilting-pad gas journal bearings and a simple externally pressurized thrust bearing. The bearing pads were 5.1 cm (2.02 in.) in diameter and 2.8 cm (1.5 in.) long. The length to diameter ratio was 0.75. One pad was mounted on a flexible diaphragm. The bearing supply pressure ranged from 0 to 690 kilonewtons per square meter (0 to 100 psig), and speeds ranged to 38,500 rpm. Heavy mass pad tilting-pad assemblies produced three rotor-bearing resonances above the first two rotor critical speeds. Lower supply pressure eliminated the resonances. The resonances were oriented primarily in the direction normal to the diaphragm.

  15. Joint lubrication.

    PubMed

    McCutchen, C W

    1983-01-01

    The fine-pored, easily compressed articular cartilage provides animal joints with self-pressurized hydrostatic (weeping) lubrication. The solid skeletons of the cartilages press against each other, but so lightly that their rubbing is lubricated successfully by synovial fluid--a boundary lubricant too weak to lubricate ordinary bearings. PMID:6317095

  16. Surface-active phospholipid: a Pandora's box of clinical applications. Part II. Barrier and lubricating properties.

    PubMed

    Hills, B A

    2002-01-01

    In Part I, it was described how their configuration renders phospholipid molecules surface active and capable of acting at interfaces in addition to the liquid-air interface to which conventional theory has hitherto confined the study of 'surfactant' in the lung. Surface-active phospholipid (SAPL) appears no different to comparable surfactants studied in the physical sciences for the highly desirable properties that their adsorption (reversible binding) can impart to solid surfaces. In Part II, these properties are considered in sites where there is no air. Highly desirable properties include boundary lubrication (lubricity), release (antistick) and the ability of the strongly adsorbed and strongly cohesive SAPL linings to act as barriers against abrasion, corrosion and, possibly, against invasion by microorganisms. As the 'sealant', it could be the true barrier rather than the cells providing its mechanical support. Evidence is reviewed for SAPL providing the gastric mucosal barrier to acid in the stomach and preventing the digestion of Helicobacter pylori until that barrier is broken by bile in the duodenum, where H. pylori cause ulcers. The concept that SAPL provides effortless sliding of many tissues, including pleura, pericardium and peritoneum is reviewed. Particular attention is paid to the load-bearing joints, where a deficiency has been associated with osteoarthritis. The ability of the same SAPL lining to perform multiple roles is discussed in relation to the peritoneum, where it could provide the lubricant/release agent preventing surgical adhesions, while imparting semipermeability to 'the membrane' vital for peritoneal dialysis. In each site, the prophylactic use of exogenous SAPL is discussed for its potential clinical applications. PMID:12036223

  17. Lubrication handbook

    NASA Technical Reports Server (NTRS)

    Campbell, M. E.; Thompson, M. B.

    1973-01-01

    Information on lubricants from government reports, military specifications, qualified parts lists, and suppliers of commercial lubricants has been consolidated in one source. Handbook includes data on chemical and physical properties of solid, bonded solid, and liquid lubricants; dispersions and composites; and greases, oils, and hydraulic fluids.

  18. Journal bearing

    DOEpatents

    Menke, John R.; Boeker, Gilbert F.

    1976-05-11

    1. An improved journal bearing comprising in combination a non-rotatable cylindrical bearing member having a first bearing surface, a rotatable cylindrical bearing member having a confronting second bearing surface having a plurality of bearing elements, a source of lubricant adjacent said bearing elements for supplying lubricant thereto, each bearing element consisting of a pair of elongated relatively shallowly depressed surfaces lying in a cylindrical surface co-axial with the non-depressed surface and diverging from one another in the direction of rotation and obliquely arranged with respect to the axis of rotation of said rotatable member to cause a flow of lubricant longitudinally along said depressed surfaces from their distal ends toward their proximal ends as said bearing members are rotated relative to one another, each depressed surface subtending a radial angle of less than 360.degree., and means for rotating said rotatable bearing member to cause the lubricant to flow across and along said depressed surfaces, the flow of lubricant being impeded by the non-depressed portions of said second bearing surface to cause an increase in the lubricant pressure.

  19. Solid lubricants

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1993-01-01

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

  20. Solid lubricants

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1991-01-01

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

  1. Positive lubrication system

    NASA Technical Reports Server (NTRS)

    Smith, Dennis W.; Hooper, Fred L.

    1990-01-01

    As part of the development of an autonomous lubrication system for spin bearings, a system was developed to deliver oil to grease-lubricated bearings upon demand. This positive oil delivery system (PLUS) consists of a pressurized reservoir with a built-in solenoid valve that delivers a predictable quantity of oil to the spin bearing through a system of stainless steel tubes. Considerable testing was performed on the PLUS to characterize its performance and verify its effectiveness, along with qualifying it for flight. Additional development is underway that will lead to the fully autonomous active lubrication system.

  2. Actively Engaging Middle Level Students with Photo Journals

    ERIC Educational Resources Information Center

    Shankar-Brown, Rajni

    2011-01-01

    The author describes the implementation of a photo journal project and explains how it positively impacted diverse young adolescents, specifically three reluctant learners. In addition to increasing motivation and engagement in learning, the photo journal project built community in the classroom. This article shares practical ideas for…

  3. Lubrication background

    NASA Technical Reports Server (NTRS)

    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.

  4. High temperature solid lubricants: When and where to use them

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1973-01-01

    The state of the art of solid lubrication for moderate to extremely high temperature lubrication (to 1600 F) is reviewed. Lubricating characteristics, stability in various environments, and relevant machine design considerations are discussed. Lubricating materials discussed include the layer lattice compounds: MoS2, WS2, graphite and graphite fluoride, the high temperature polyimide polymer, and calcium fluoride based coating and composites. The scope of the information includes results from wear testers, ball bearing, and journal bearings.

  5. High temperature solid lubricants - When and where to use them.

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1973-01-01

    This paper reviews the state of the art of solid lubrication for moderate to extremely high temperature lubrication (to 1600 F). Lubricating characteristics, stability in various environments, and relevant machine design considerations are discussed. Lubricating materials discussed include MoS2, WS2, graphite, graphite fluoride, the high temperature polymide polymer, and calcium fluoride based coatings and composites. The scope of the information includes results from wear testers, ball bearings, and journal bearings.

  6. Lubrication and cartilage.

    PubMed Central

    Wright, V; Dowson, D

    1976-01-01

    Mechanisms of lubrication of human synovial joints have been analysed in terms of the operating conditions of the joint, the synovial fluid and articular cartilage. In the hip and knee during a walking cycle the load may rise up to four times body weight. In the knee on dropping one metre the load may go up to 25 time body weight. The elastic modulus of cartilage is similar to that of the synthetic rubber of a car tyre. The cartilage surface is rough and in elderly specimens the centre line average is 2-75 mum. The friction force generated in reciprocating tests shows that both cartilage and synovial fluid are important in lubrication. The viscosity-shear rate relationships of normal synovial fluid show that it is non-Newtonian. Osteoarthrosic fluid is less so and rheumatoid fluid is more nearly Newtonian. Experiments with hip joints in a pendulum machine show that fluid film lubrication obtains at some phases of joint action. Boundary lubrication prevails under certain conditions and has been examined with a reciprocating friction machine. Digestion of hyaluronate does not alter the boundary lubrication, but trypsin digestion does. Surface active substances (lauryl sulphate and cetyl 3-ammonium bromide) give a lubricating ability similar to that of synovial fluid. The effectiveness of the two substances varies with pH. Images Fig. 10 PMID:3490

  7. Mechanics and thermodynamics in lubrication

    NASA Technical Reports Server (NTRS)

    Cameron, A.; Gentle, C. R.

    1973-01-01

    The causes for breakdown in the lubricant film of mineral oils are discussed. It is stated that the critical point is caused by desorption of the naturally occurring surface active agent and can be described by thermodynamic analysis. The effect of different metals in lubrication is surveyed. The problem of breakdown in elastohydrodynamic lubrication is treated phenomenologically by studying traction. The topics considered are classical and non-Newtonian explanations, anomalous film thickness and viscosity effects, surface roughness contributions, and solidification of the lubricant. Reasons for the apparent granular traction characteristics are examined.

  8. The role of children's journals in elementary school science activities

    NASA Astrophysics Data System (ADS)

    Shepardson, Daniel P.; Britsch, Susan J.

    2001-01-01

    : This article reports on a study that investigated the ways that children's use of science journals aided their acquisition of science understandings in one kindergarten and one fourth-grade classroom. The questions for investigation were: how does the child contextualize the science experience on the journal page? How do child-produced graphics on the journal page reflect the children's experiences with other school texts? The study found that children recontextualized their understandings of the science investigation and phenomena by using three types of mental contexts that were reflected in their science journals: these contexts were imaginary, experienced, and investigative worlds. By drawing on these three worlds or internal contexts, the children were able to pull the external phenomenon into an internal context that was familiar to them. The child's construction of ideas about a current science experience as expressed on the journal page may reflect experiences with other conventional texts. In this study the children's representations of their imaginary, experienced and/or investigative worlds were shaped by other texts and structures such as school science texts.

  9. Marine Lubricants

    NASA Astrophysics Data System (ADS)

    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.

  10. Assessing the Impact Participation in Science Journalism Activities Has on Scientific Literacy among High School Students

    ERIC Educational Resources Information Center

    Farrar, Cathy

    2012-01-01

    As part of the National Science Foundation Science Literacy through Science Journalism (SciJourn) research and development initiative (http://www.scijourn.org; Polman, Saul, Newman, and Farrar, 2008) a quasi-experimental design was used to investigate what impact incorporating science journalism activities had on students' scientific literacy.…

  11. Using Guided Reflective Journaling Activities to Capture Students' Changing Perceptions

    ERIC Educational Resources Information Center

    Dunlap, Joanna C.

    2006-01-01

    Many professions are increasingly emphasizing the role of reflection, encouraging educators to look for appropriate ways to help students engage in reflective practice during their professional preparation. Journal writing is an insightful and powerful instructional technology utilizing strategies that foster understanding and the application of…

  12. Space Station lubrication considerations

    NASA Technical Reports Server (NTRS)

    Leger, Lubert J.; Dufrane, Keith

    1987-01-01

    Future activities in space will require the use of large structures and high power availability in order to fully exploit opportunities in Earth and stellar observations, space manufacturing and the development of optimum space transportation vehicles. Although these large systems will have increased capabilities, the associated development costs will be high, and will dictate long life with minimum maintenance. The Space Station provides a concrete example of such a system; it is approximately one hundred meters in major dimensions and has a life requirement of thirty years. Numerous mechanical components will be associated with these systems, a portion of which will be exposed to the space environment. If the long life and low maintenance goals are to be satisfied, lubricants and lubrication concepts will have to be carefully selected. Current lubrication practices are reviewed with the intent of determining acceptability for the long life requirements. The effects of exposure of lubricants and lubricant binders to the space environment are generally discussed. Potential interaction of MoS2 with atomic oxygen, a component of the low Earth orbit environment, appears to be significant.

  13. Advanced Lubricants

    NASA Technical Reports Server (NTRS)

    1996-01-01

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

  14. Bonded Lubricants

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Another spinoff to the food processing industry involves a dry lubricant developed by General Magnaplate Corp. of Linden, N.J. Used in such spacecraft as Apollo, Skylab and Viking, the lubricant is a coating bonded to metal surfaces providing permanent lubrication and corrosion resistance. The coating lengthens equipment life and permits machinery to be operated at greater speed, thus increasing productivity and reducing costs. Bonded lubricants are used in scores of commercia1 applications. They have proved particularly valuable to food processing firms because, while increasing production efficiency, they also help meet the stringent USDA sanitation codes for food-handling equipment. For example, a cookie manufacturer plagued production interruptions because sticky batter was clogging the cookie molds had the brass molds coated to solve the problem. Similarly, a pasta producer faced USDA action on a sanitation violation because dough was clinging to an automatic ravioli-forming machine; use of the anti-stick coating on the steel forming plates solved the dual problem of sanitation deficiency and production line downtime.

  15. Lubrication Flows.

    ERIC Educational Resources Information Center

    Papanastasiou, Tasos C.

    1989-01-01

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

  16. Investigation of lubricants under boundary friction

    NASA Technical Reports Server (NTRS)

    Heidebroek, E; Pietsch, E

    1942-01-01

    Numerous observations of such lubrication processes within range of boundary friction on journal bearings and gear tooth profiles have strengthened the supposition that it should be possible to study the attendant phenomena with engineering methods and equipment. These considerations formed the basis of the present studies, which have led to the discovery of relations governing the suitability of bearing surfaces and the concept of "lubricating quality."

  17. Tethered Lubricants

    SciTech Connect

    Archer, Lynden

    2010-09-15

    We have performed extensive experimental and theoretical studies of interfacial friction, relaxation dynamics, and thermodynamics of polymer chains tethered to points, planes, and particles. A key result from our tribology studies using lateral force microscopy (LFM) measurements of polydisperse brushes of linear and branched chains densely grafted to planar substrates is that there are exceedingly low friction coefficients for these systems. Specific project achievements include: (1) Synthesis of three-tiered lubricant films containing controlled amounts of free and pendent PDMS chains, and investigated the effect of their molecular weight and volume fraction on interfacial friction. (2.) Detailed studies of a family of hairy particles termed nanoscale organic hybrid materials (NOHMs) and demonstration of their use as lubricants.

  18. Aviation Lubricants

    NASA Astrophysics Data System (ADS)

    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.

  19. 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.

    ERIC Educational Resources Information Center

    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…

  20. Liquid lubrication for space applications

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.; Khonsari, Michael M.

    1992-01-01

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

  1. Liquid cryogenic lubricant

    NASA Technical Reports Server (NTRS)

    Dietrich, M. W.; Townsend, D. P.; Zaretsky, E. V.

    1970-01-01

    Fluorinated polyethers are suitable lubricants for rolling-element bearings in cryogenic systems. Lubrication effectiveness is comparable to that of super-refined mineral oil lubricants operating at room temperature.

  2. Introduction of a Journal Excerpt Activity Improves Undergraduate Students' Performance in Statistics

    ERIC Educational Resources Information Center

    Rabin, Laura A.; Nutter-Upham, Katherine E.

    2010-01-01

    We describe an active learning exercise intended to improve undergraduate students' understanding of statistics by grounding complex concepts within a meaningful, applied context. Students in a journal excerpt activity class read brief excerpts of statistical reporting from published research articles, answered factual and interpretive questions,…

  3. Engine Lubricant

    NASA Technical Reports Server (NTRS)

    1993-01-01

    PS 212, a plasma-sprayed coating developed by NASA, is used to coat valves in a new rotorcam engine. The coating eliminates the need for a liquid lubricant in the rotorcam, which has no crankshaft, flywheel, distributor or water pump. Developed by Murray United Development Corporation, it is a rotary engine only 10 inches long with four cylinders radiating outward from a central axle. Company officials say the engine will be lighter, more compact and cheaper to manufacture than current engines and will feature cleaner exhaust emissions. A licensing arrangement with a manufacturer is under negotiation. Primary applications are for automobiles, but the engine may also be used in light aircraft.

  4. BIOLOGICALLY ENHANCED OXYGEN TRANSFER IN THE ACTIVATED SLUDGE PROCESS (JOURNAL)

    EPA Science Inventory

    Biologically enhanced oxgyen transfer has been a hypothesis to explain observed oxygen transfer rates in activated sludge systems that were well above that predicted from aerator clean-water testing. The enhanced oxygen transfer rates were based on tests using BOD bottle oxygen ...

  5. Citation Networks as Indicators of Journalism Research Activity.

    ERIC Educational Resources Information Center

    Tankard, James W.; And Others

    1984-01-01

    Reviews citation networks and discovers that the six major areas of activity in mass communication research are (1) television and politics, (2) sociological studies of journalists, (3) agenda setting, (4) the effects of mass communication, (5) the credibility of various news media, and (6) the characteristics of users and nonusers of mass media.…

  6. A Journal-Club-Based Class that Promotes Active and Cooperative Learning of Biology

    ERIC Educational Resources Information Center

    Kitazono, Ana A.

    2010-01-01

    A journal-club-based class has been developed to promote active and cooperative learning and expose seniors in biochemistry and cellular molecular biology to recent research in the field. Besides giving oral presentations, students also write three papers: one discussing an article of their own choosing and two, discussing articles presented by…

  7. Impact of lubricant additives on the physicochemical properties and activity of three-way catalysts

    DOE PAGESBeta

    Toops, Todd J.; Lance, Michael J.; Qu, Jun; Viola, Michael B; Lewis, Samuel Arthur; Leonard, Donovan N.; Edward W. Hagaman; Xie, Chao

    2016-04-04

    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 temperaturesmore » 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. Furthermore, the results in this work indicate that the phosphonium-phosphate IL potentially has less adverse impact on TWC than ZDDP.« less

  8. Vibration Control in Turbomachinery Using Active Magnetic Journal Bearings

    NASA Technical Reports Server (NTRS)

    Knight, Josiah D.

    1996-01-01

    The effective use of active magnetic bearings for vibration control in turbomachinery depends on an understanding of the forces available from a magnetic bearing actuator. The purpose of this project was to characterize the forces as functions shaft position. Both numerical and experimental studies were done to determine the characteristics of the forces exerted on a stationary shaft by a magnetic bearing actuator. The numerical studies were based on finite element computations and included both linear and nonlinear magnetization functions. Measurements of the force versus position of a nonrotating shaft were made using two separate measurement rigs, one based on strain gage measurement of forces, the other based on deflections of a calibrated beam. The general trends of the measured principal forces agree with the predictions of the theory while the magnitudes of forces are somewhat smaller than those predicted. Other aspects of theory are not confirmed by the measurements. The measured forces in the normal direction are larger than those predicted by theory when the rotor has a normal eccentricity. Over the ranges of position examined, the data indicate an approximately linear relationship between the normal eccentricity of the shaft and the ratio of normal to principal force. The constant of proportionality seems to be larger at lower currents, but for all cases examined its value is between 0.14 and 0.17. The nonlinear theory predicts the existence of normal forces, but has not predicted such a large constant of proportionality for the ratio. The type of coupling illustrated by these measurements would not tend to cause whirl, because the coupling coefficients have the same sign, unlike the case of a fluid film bearing, where the normal stiffness coefficients often have opposite signs. They might, however, tend to cause other self-excited behavior. This possibility must be considered when designing magnetic bearings for flexible rotor applications, such as gas

  9. 49 CFR 230.102 - Tender plain bearing journal boxes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Tender plain bearing journal boxes. 230.102... Locomotives and Tenders Running Gear § 230.102 Tender plain bearing journal boxes. Plain bearing journal boxes... expected to damage the bearing; or have a detrimental effect on the lubrication of the journal and...

  10. 49 CFR 230.102 - Tender plain bearing journal boxes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Tender plain bearing journal boxes. 230.102... Locomotives and Tenders Running Gear § 230.102 Tender plain bearing journal boxes. Plain bearing journal boxes... expected to damage the bearing; or have a detrimental effect on the lubrication of the journal and...

  11. 49 CFR 230.102 - Tender plain bearing journal boxes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Tender plain bearing journal boxes. 230.102... Locomotives and Tenders Running Gear § 230.102 Tender plain bearing journal boxes. Plain bearing journal boxes... expected to damage the bearing; or have a detrimental effect on the lubrication of the journal and...

  12. 49 CFR 230.102 - Tender plain bearing journal boxes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Tender plain bearing journal boxes. 230.102... Locomotives and Tenders Running Gear § 230.102 Tender plain bearing journal boxes. Plain bearing journal boxes... expected to damage the bearing; or have a detrimental effect on the lubrication of the journal and...

  13. 49 CFR 230.102 - Tender plain bearing journal boxes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Tender plain bearing journal boxes. 230.102... Locomotives and Tenders Running Gear § 230.102 Tender plain bearing journal boxes. Plain bearing journal boxes... expected to damage the bearing; or have a detrimental effect on the lubrication of the journal and...

  14. Biodiesel Impact on Engine Lubricant Dilution During Active Regeneration of Aftertreatment Systems

    SciTech Connect

    He, X.; Williams, A.; Christensen, E.; Burton, J.; McCormick, R.

    2011-12-01

    Experiments were conducted with ultra low sulfur diesel (ULSD) and 20% biodiesel blends (B20) to compare lube oil dilution levels and lubricant properties for systems using late in-cylinder fuel injection for aftertreatment regeneration. Lube oil dilution was measured by gas chromatography (GC) following ASTM method D3524 to measure diesel content, by Fourier transform infrared (FTIR) spectrometry following a modified ASTM method D7371 to measure biodiesel content, and by a newly developed back-flush GC method that simultaneously measures both diesel and biodiesel. Heavy-duty (HD) engine testing was conducted on a 2008 6.7L Cummins ISB equipped with a diesel oxidation catalyst (DOC) and diesel particle filter (DPF). Stage one of engine testing consisted of 10 consecutive repeats of a forced DPF regeneration event. This continuous operation with late in-cylinder fuel injection served as a method to accelerate lube-oil dilution. Stage two consisted of 16 hours of normal engine operation over a transient test cycle, which created an opportunity for any accumulated fuel in the oil sump to evaporate. Light duty (LD) vehicle testing was conducted on a 2010 VW Jetta equipped with DOC, DPF and a NOx storage catalyst (NSC). Vehicle testing comprised approximately 4,000 miles of operation on a mileage-accumulation dynamometer (MAD) using the U.S. Environmental Protection Agency's Highway Fuel Economy Cycle because of the relatively low engine oil and exhaust temperatures, and high DPF regeneration frequency of this cycle relative to other cycles examined. Comparison of the lube oil dilution analysis methods suggests that D3524 does not measure dilution by biodiesel. The new back-flush GC method provided analysis for both diesel and biodiesel, in a shorter time and with lower detection limit. Thus all lube oil dilution results in this paper are based on this method. Analysis of the HD lube-oil samples showed only 1.5% to 1.6% fuel dilution for both fuels during continuous

  15. Lubrication with solids.

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.; Johnson, R. L.

    1972-01-01

    Brief discussion of the historical background, variety range, chemistry, physics, and other properties of solid lubricants, and review of their current uses. The widespread use of solid lubricants did not occur until about 1947. At present, they are the object of such interest that a special international conference on their subject was held in 1971. They are used at temperatures beyond the useful range of conventional lubricating oils and greases. Their low volatility provides them with the capability of functioning effectively in vacuum and invites their use in space applications. Their high load carrying ability makes them useful with heavily loaded components. Solid lubricants, however, do lack some of the desirable properties of conventional lubricants. Unlike oils and greases, which have fluidity and can continuously be carried back into contact with lubricated surfaces, solid lubricants, because of their immobility, have finite lives. Also, oils and greases can carry away frictional heat from contacting surfaces, while solid lubricants cannot.

  16. Thermally-Activated Pentanol Delivery from Precursor Poly( p -phenylenevinylene)s for MEMS Lubrication

    SciTech Connect

    Johnson, Ross S.; Washburn, Cody M.; Staton, Alan W.; Moorman, Matthew W.; Manginell, Ronald P.; Dugger, Michael T.; Dirk, Shawn M.

    2012-07-18

    The synthesis of two new polyphenylene vinylene (PPV) precursor polymers which can be thermally induced to eliminate pentanol is presented. Pentanol has recently been discovered to be a very useful lubricant in MicroElectroMechanical Systems. The utilization of the elimination reaction of precursor polymers to PPV as a small molecule delivery platform has, to the best of our knowledge, not been previously reported. The elimination reactions were examined using thermal gravimetric analysis, gas chromatography, and UV–Vis spectroscopy. Using PPV precursors allows for (1) a high loading of lubricant (one molecule per monomeric unit), (2) a platform that requires relatively high temperatures (>145 °C) to eliminate the lubricant, and (3) a non-volatile, mechanically and chemically stable by-product of the elimination reaction (PPV).

  17. Seal/lubricant systems for geothermal drilling equipment

    SciTech Connect

    Hendrickson, R.R.; Winzenried, R.W.

    1980-07-01

    The development and testing of seals and lubricants for journal-type roller-cone rock bits for drilling into geothermal reservoirs at temperatures over 260/sup 0/C (500/sup 0/F) are described. The conditions experienced by seals and lubricants subjected to geothermal drilling are reviewed along with the basic design requirements for roller-cone bit seals and journal bearing lubricants. Two unique test facilities are described: a seal test machine which simulates pressures, temperatures, and mechanical eccentricities, and a lubricant tester capable of evaluating load-bearing ability at temperature and pressure. Three candidate elastomeric compounds demonstrated 288/sup 0/C (550/sup 0/F) capability and several others demonstrated 260/sup 0/C (500/sup 0/F) or greater capability. Successful elastomeric seal candidates were proprietary compounds based on EPDM, Kalrez, and/or Viton polymers. Three mechanical seals for reservoir temperatures over 288/sup 0/C (550/sup 0/F) are presented. Lubricant screening tests on more than 50 products are summarized, and several newly developed lubricants which meet both the compatibility and lubrication requirements are described. Several seal/lubricant systems are recommended for laboratory or field geothermal drilling tests in roller-cone drill bits. The future availability of drill bits for geothermal use is discussed, as well as the potential spinoffs of the program findings for nongeothermal roller-cone bits.

  18. Solid Lubricant For Alumina

    NASA Technical Reports Server (NTRS)

    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.

  19. Lubricant rheology applied to elastohydrodynamic lubrication

    NASA Technical Reports Server (NTRS)

    Winer, W. O.; Sanborn, D. M.

    1977-01-01

    Viscosity measurements in a high pressure rheometer, elastohydrodynamic simulator studies (including the development of a temperature measuring technique), and analytical fluid modeling for elastohydrodynamic contacts are described. The more recent research which is described concerns infrared temperature measurements in elastohydrodynamic contacts and the exploration of the glassy state of lubricants. A correlation, of engineering significance, was made between transient surface temperature measurements and surface roughness profiles. Measurements of glass transitions of lubricants and the study of the effect of rate processes on materials lead to the conclusion that typical lubricants go into the glassy state as they pass through the contact region of typical elastohydrodynamic contacts.

  20. Analyzing Children's Science Journals.

    ERIC Educational Resources Information Center

    Shepardson, Daniel P.; Britsch, Susan J.

    2000-01-01

    Explains the process of using science journals with first and second grade students in three activities to explore the instructional sequence. Suggests some strategies to use journals more effectively and makes recommendations on important points for student evaluation. (YDS)

  1. Scientific Journalism in Armenia

    NASA Astrophysics Data System (ADS)

    Farmanyan, S. V.; Mickaelian, A. M.

    2015-07-01

    In the present study, the problems of scientific journalism and activities of Armenian science journalists are presented. Scientific journalism in the world, forms of its activities, Armenian Astronomical Society (ArAS) press-releases and their subjects, ArAS website "Mass Media News" section, annual and monthly calendars of astronomical events, and "Astghagitak" online journal are described. Most interesting astronomical subjects involved in scientific journalism, reasons for non-satisfactory science outreach and possible solutions are discussed.

  2. Lubrication of Nitinol 60

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  3. Boundary lubrication: Revisited

    NASA Technical Reports Server (NTRS)

    Jones, W. R., Jr.

    1982-01-01

    A review of the various lubrication regimes, with particular, emphasis on boundary lubrication, is presented. The types of wear debris and extent of surface damage is illustrated for each regime. The role of boundary surface films along with their modes of formation and important physical properties are discussed. In addition, the effects of various operating parameters on friction and wear in the boundary lubrication regime are considered.

  4. Lubrication of Machine Elements

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.

    1984-01-01

    The understanding of hydrodynamic lubrication began with the classical experiments of Tower and Petrov. Reynolds used a reduced form of the Navier-Stokes equations and the continuity equation to generate a second order differential equation for the pressure in the narrow, converging gap of a bearing contact. Such a pressure enables a load to be transmitted between the surfaces with very low friction since the surfaces are completely separated by a film of fluid. In such a situation it is the physical properties of the lubricant, notably the dynamic viscosity, that dictate the behavior of the contact. The understanding of boundary lubrication is normally attributed to Hardy and Doubleday. In boundary lubrication it is the physical and chemical properties of thin films of molecular proportions and the surfaces to which they are attached that determine contact behavior. The lubricant viscosity is not an influential parameter. Research is devoted to a better understanding and more precise definition of other lubrication regimes between these extremes. One such regime, elastohydrodynamic lubrication, occurs in nonconformal contacts, where the pressures are high and the bearing surfaces deform elastically. In this situation the viscosity of the lubricant may raise considerably, and this further assists the formation of an effective fluid film. The science of these three lubrication regimes (hydrodynamic, elastohydrodynamic, and boundary) are described and the manner in which this science is used in the design of machine elements is examined.

  5. Fundamentals of fluid lubrication

    NASA Technical Reports Server (NTRS)

    Hamrock, Bernard J.

    1991-01-01

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

  6. DIESEL FUEL LUBRICATION

    SciTech Connect

    Qu, Jun

    2012-01-01

    The diesel fuel injector and pump systems contain many sliding interfaces that rely for lubrication upon the fuels. The combination of the poor fuel lubricity and extremely tight geometric clearance between the plunger and bore makes the diesel fuel injector vulnerable to scuffing damage that severely limits the engine life. In order to meet the upcoming stricter diesel emission regulations and higher engine efficiency requirements, further fuel refinements that will result in even lower fuel lubricity due to the removal of essential lubricating compounds, more stringent operation conditions, and tighter geometric clearances are needed. These are expected to increase the scuffing and wear vulnerability of the diesel fuel injection and pump systems. In this chapter, two approaches are discussed to address this issue: (1) increasing fuel lubricity by introducing effective lubricity additives or alternative fuels, such as biodiesel, and (2) improving the fuel injector scuffing-resistance by using advanced materials and/or surface engineering processes. The developing status of the fuel modification approach is reviewed to cover topics including fuel lubricity origins, lubricity improvers, alternative fuels, and standard fuel lubricity tests. The discussion of the materials approach is focused on the methodology development for detection of the onset of scuffing and evaluation of the material scuffing characteristics.

  7. Assessing the impact participation in science journalism activities has on scientific literacy among high school students

    NASA Astrophysics Data System (ADS)

    Farrar, Cathy

    As part of the National Science Foundation Science Literacy through Science Journalism (SciJourn) research and development initiative (http://www.scijourn.org ; Polman, Saul, Newman, and Farrar, 2008) a quasi-experimental design was used to investigate what impact incorporating science journalism activities had on students' scientific literacy. Over the course of a school year students participated in a variety of activities culminating in the production of science news articles for Scijourner, a regional print and online high school science news magazine. Participating teachers and SciJourn team members collaboratively developed activities focused on five aspects of scientific literacy: placing information into context, recognizing relevance, evaluating factual accuracy, use of multiple credible sources and information seeking processes. This study details the development process for the Scientific Literacy Assessment (SLA) including validity and reliability studies, evaluates student scientific literacy using the SLA, examines student SLA responses to provide a description of high school students' scientific literacy, and outlines implications of the findings in relation to the National Research Council's A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (2012) and classroom science teaching practices. Scientifically literate adults acting as experts in the assessment development phase informed the creation of a scoring guide that was used to analyze student responses. Experts tended to draw on both their understanding of science concepts and life experiences to formulate answers; paying close attention to scientific factual inaccuracies, sources of information, how new information fit into their view of science and society as well as targeted strategies for information seeking. Novices (i.e., students), in contrast, tended to ignore factual inaccuracies, showed little understanding about source credibility and suggested

  8. Wear characteristics of bonded solid film lubricant under high load condition

    NASA Technical Reports Server (NTRS)

    Hiraoka, Naofumi; Sasaki, Akira; Kawashima, Noritsugu; Honda, Toshio

    1991-01-01

    Wear properties of phenolic resin bonded molybdenum disulfide film lubricant were studied. In-vacuo journal bearing tests were performed to evaluate the wear-life of this film lubricant. The wear-life depends on substrate materials and on sliding velocity. Pretreated substrate surfaces were examined to reveal the reasons for these results. Additionally, investigations on film wear mechanisms were made.

  9. Plasma-sprayed metal-glass fluoride coatings for lubrication to 1170 K (1650 F)

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1974-01-01

    Plasma spray of Nichrome matrix composite contains dispersed glass for oxidation protection and calcium fluoride for lubrication. Coatings can be applied to bearing journals and bearing bores. Coating was easily machinable and had excellent bond strength on substrate metal.

  10. Ocean Spray Lubricates Winds

    ERIC Educational Resources Information Center

    Journal of College Science Teaching, 2005

    2005-01-01

    According to a new study by two University of California, Berkeley, mathematicians and their Russian colleague, the water droplets kicked up by rough seas serve to lubricate the swirling winds of hurricanes and cyclones, letting them build to speeds approaching 200 miles per hour. Without the lubricating effect of the spray, the mathematicians…

  11. Self-lubricating gear

    NASA Technical Reports Server (NTRS)

    Demorest, K. E.

    1969-01-01

    Self-lubricating gear, designed for long term operation in a vacuum at high, low, and ambient temperatures, is constructed of alternating layers of metal and a dry lubricant material, such as polytetrafluoroethylene, with a suitable reinforcing material bonded into a laminated composite unit, which is machined to form a standard gear.

  12. Cooperative industry-military activities during World War II related to ordnance transport and combat vehicles, fuels and lubricants

    SciTech Connect

    Way, G

    1988-01-01

    Liaison between the Coordinating Research Council (CRC) and the Military Forces began before World War II. It was implemented when an M3-A3 light tank was shipped to San Bernardino, California, to participate in the 1940 CFR Road Test Program. This resulted from earlier recognition that expertise developed in industry should be made available on problems anticipated in military war-time operations. Accordingly, early in 1942, CRC organized test teams to study problems in operations under extreme ambient conditions that were related to fuels and lubricants. The CRC War Advisory Committee was formed about the same time to coordinate and, through CRC, plan the programs.

  13. High temperature lubricating process

    DOEpatents

    Taylor, R.W.; Shell, T.E.

    1979-10-04

    It has been difficult to provide adequate lubrication for load bearing, engine components when such engines are operating in excess of about 475/sup 0/C. The present invention is a process for providing a solid lubricant on a load bearing, solid surface, such as in an engine being operated at temperatures in excess of about 475/sup 0/C. The process comprises contacting and maintaining the following steps: a gas phase is provided which includes at least one component reactable in a temperature dependent reaction to form a solid lubricant; the gas phase is contacted with the load bearing surface; the load bearing surface is maintained at a temperature which causes reaction of the gas phase component and the formation of the solid lubricant; and the solid lubricant is formed directly on the load bearing surface. The method is particularly suitable for use with ceramic engines.

  14. Sporting Good Lubricants

    NASA Technical Reports Server (NTRS)

    1997-01-01

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

  15. Journals Abroad

    ERIC Educational Resources Information Center

    Ando, Shoichi

    1975-01-01

    This article summarizes four journal articles on language teaching appearing in the American pedagogical language journals, "The Modern Language Journal,""English Language Teaching Journal," and "TESOL Quarterly." The purpose is to give an indication of what kinds of articles can be found in journals outside Japan. (Text is in Japanese.) (TL)

  16. Dynamic-reservoir lubricating device

    NASA Technical Reports Server (NTRS)

    Ficken, W. H.; Schulien, H. E.

    1968-01-01

    Dynamic-reservoir lubricating device supplies controlled amounts of lubricating oil to ball bearings during operation of the bearings. The dynamic reservoir lubricating device includes a rotating reservoir nut, a hollow cylinder filled with lubricating oil, flow restrictors and a ball bearing retainer.

  17. Dairy Equipment Lubrication

    NASA Technical Reports Server (NTRS)

    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.

  18. Environmentally friendly lubricating oil candidate.

    PubMed

    Ozgülsün, A; Karaosmanoğlu, F

    1999-01-01

    Synthetic lubricating oils based on renewable sources, excluding petroleum, have a great importance among all of the lubricating oil alternatives that are included in the research field about clean and environmentally friendly lubricating oil technologies. One of the environmentally friendly lubricating oils is a vegetable oil-based product. In this study, the esterification product of oleic acid with a fraction of molasses fusel oil as a lubricating oil candidate was determined according to the American Society for Testing and Materials (ASTM) standard tests. The results indicate that the ester product can be used as an environmental friendly lubricating oil or lubricating oil additive. PMID:10399269

  19. A Systems Approach to the Solid Lubrication of Foil Air Bearings for Oil-Free Turbomachinery

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Zaldana, Antonio R.; Radil, Kevin C.

    2002-01-01

    Foil air bearings are self-acting hydrodynamic bearings which rely upon solid lubricants to reduce friction and minimize wear during sliding which occurs at start-up and shut-down when surface speeds are too low to allow the formation of a hydrodynamic air film. This solid lubrication is typically accomplished by coating the non-moving foil surface with a thin, soft polymeric film. The following paper introduces a systems approach in which the solid lubrication is provided by a combination of self lubricating shaft coatings coupled with various wear resistant and lubricating foil coatings. The use of multiple materials, each providing different functions is modeled after oil-lubricated hydrodynamic sleeve bearing technology which utilizes various coatings and surface treatments in conjunction with oil lubricants to achieve optimum performance. In this study, room temperature load capacity tests are performed on journal foil air bearings operating at 14,000 rpm. Different shaft and foil coating technologies such as plasma sprayed composites, ceramic, polymer and inorganic lubricant coatings are evaluated as foil bearing lubricants. The results indicate that bearing performance is improved through the individual use of the lubricants and treatments tested. Further, combining several solid lubricants together yielded synergistically better results than any material alone.

  20. Tribometer for Lubrication Studies in Vacuum

    NASA Technical Reports Server (NTRS)

    Pepper, Stephen V.

    1998-01-01

    orbit radius. The friction force due to gross sliding is sensed by the piezoelectric force transducer behind the guide plate and furnishes the coefficient of friction for the system. This tribometer has been used to determine the relative lifetimes of Fomblin Z-25, a lubricant often used in space mechanisms, as a function of the material of the plates against which it was run. The balls were 440C steel in all cases; the plate materials were aluminum, chromium (Cr), 440C steel (17 wt % Cr), and 4150 steel (1 wt % Cr). As shown in the bar graph, the lifetime is greatest for the plate material with least chromium, thus implicating chromium as a tribochemically active element attacking Fomblin Z-25.

  1. Origins of hydration lubrication

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  2. Liquid lubrication in space

    NASA Technical Reports Server (NTRS)

    Zaretsky, Erwin V.

    1990-01-01

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

  3. Solid lubrication design methodology

    NASA Technical Reports Server (NTRS)

    Aggarwal, B. B.; Yonushonis, T. M.; Bovenkerk, R. L.

    1984-01-01

    A single element traction rig was used to measure the traction forces at the contact of a ball against a flat disc at room temperature under combined rolling and sliding. The load and speed conditions were selected to match those anticipated for bearing applications in adiabatic diesel engines. The test program showed that the magnitude of traction forces were almost the same for all the lubricants tested; a lubricant should, therefore, be selected on the basis of its ability to prevent wear of the contact surfaces. Traction vs. slide/roll ratio curves were similar to those for liquid lubricants but the traction forces were an order of magnitude higher. The test data was used to derive equations to predict traction force as a function of contact stress and rolling speed. Qualitative design guidelines for solid lubricated concentrated contacts are proposed.

  4. Origins of hydration lubrication.

    PubMed

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

    2015-01-01

    Why is friction in healthy hips and knees so low? Hydration lubrication, according to which hydration shells surrounding charges act as lubricating elements in boundary layers (including those coating cartilage in joints), has been invoked to account for the extremely low sliding friction between surfaces in aqueous media, but not well understood. Here we report the direct determination of energy dissipation within such sheared hydration shells. By trapping hydrated ions in a 0.4-1 nm gap between atomically smooth charged surfaces as they slide past each other, we are able to separate the dissipation modes of the friction and, in particular, identify the viscous losses in the subnanometre hydration shells. Our results shed light on the origins of hydration lubrication, with potential implications both for aqueous boundary lubricants and for biolubrication. PMID:25585501

  5. Externally Pressurized Journal Gas Bearings

    NASA Technical Reports Server (NTRS)

    Laub, John H.

    1959-01-01

    Externally pressurized gas-lubricated bearings with multiple orifice feed are investigated. An analytical treatment is developed for a semi-cylindrical bearing with 9 orifices and for a cylindrical journal bearing with 192 radial and 24 axial orifices. Experiments are described on models of the two bearing configurations with specially designed fixtures which incorporate pneumatic loading and means for determining pressure profiles, gas flow and gap height. The correlation between theory and experiment is satisfactory.

  6. Lubrication by glycoprotein brushes.

    NASA Astrophysics Data System (ADS)

    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.

  7. Methods to improve lubricity of fuels and lubricants

    SciTech Connect

    Erdemir, Ali

    2009-06-16

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

  8. Imbalance in individual researcher's peer review activities quantified for four British Ecological Society journals, 2003-2010.

    PubMed

    Petchey, Owen L; Fox, Jeremy W; Haddon, Lindsay

    2014-01-01

    Researchers contribute to the scientific peer review system by providing reviews, and "withdraw" from it by submitting manuscripts that are subsequently reviewed. So far as we are aware, there has been no quantification of the balance of individual's contributions and withdrawals. We compared the number of reviews provided by individual researchers (i.e., their contribution) to the number required by their submissions (i.e. their withdrawals) in a large and anonymised database provided by the British Ecological Society. The database covered the Journal of Ecology, Journal of Animal Ecology, Journal of Applied Ecology, and Functional Ecology from 2003-2010. The majority of researchers (64%) did not have balanced contributions and withdrawals. Depending on assumptions, 12% to 44% contributed more than twice as much as required; 20% to 52% contributed less than half as much as required. Balance, or lack thereof, varied little in relation to the number of years a researcher had been active (reviewing or submitting). Researchers who contributed less than required did not lack the opportunity to review. Researchers who submitted more were more likely to accept invitations to review. These finding suggest overall that peer review of the four analysed journals is not in crisis, but only due to the favourable balance of over- and under-contributing researchers. These findings are limited to the four journals analysed, and therefore cannot include researcher's other peer review activities, which if included might change the proportions reported. Relatively low effort was required to assemble, check, and analyse the data. Broader analyses of individual researcher's peer review activities would contribute to greater quality, efficiency, and fairness in the peer review system. PMID:24658631

  9. Imbalance in Individual Researcher's Peer Review Activities Quantified for Four British Ecological Society Journals, 2003-2010

    PubMed Central

    Petchey, Owen L.; Fox, Jeremy W.; Haddon, Lindsay

    2014-01-01

    Researchers contribute to the scientific peer review system by providing reviews, and “withdraw” from it by submitting manuscripts that are subsequently reviewed. So far as we are aware, there has been no quantification of the balance of individual's contributions and withdrawals. We compared the number of reviews provided by individual researchers (i.e., their contribution) to the number required by their submissions (i.e. their withdrawals) in a large and anonymised database provided by the British Ecological Society. The database covered the Journal of Ecology, Journal of Animal Ecology, Journal of Applied Ecology, and Functional Ecology from 2003–2010. The majority of researchers (64%) did not have balanced contributions and withdrawals. Depending on assumptions, 12% to 44% contributed more than twice as much as required; 20% to 52% contributed less than half as much as required. Balance, or lack thereof, varied little in relation to the number of years a researcher had been active (reviewing or submitting). Researchers who contributed less than required did not lack the opportunity to review. Researchers who submitted more were more likely to accept invitations to review. These finding suggest overall that peer review of the four analysed journals is not in crisis, but only due to the favourable balance of over- and under-contributing researchers. These findings are limited to the four journals analysed, and therefore cannot include researcher's other peer review activities, which if included might change the proportions reported. Relatively low effort was required to assemble, check, and analyse the data. Broader analyses of individual researcher's peer review activities would contribute to greater quality, efficiency, and fairness in the peer review system. PMID:24658631

  10. Power system with an integrated lubrication circuit

    SciTech Connect

    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.

  11. Lubrication of Space Systems (c)

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    1995-01-01

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

  12. Computational Chemistry and Lubrication

    NASA Technical Reports Server (NTRS)

    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.

  13. Fluid lubricated bearing assembly

    DOEpatents

    Boorse, Henry A.; Boeker, Gilbert F.; Menke, John R.

    1976-01-01

    1. A support for a loaded rotatable shaft comprising in combination on a housing having a fluid-tight cavity encasing an end portion of said shaft, a thrust bearing near the open end of said cavity for supporting the axial thrust of said shaft, said thrust bearing comprising a thrust plate mounted in said housing and a thrust collar mounted on said shaft, said thrust plate having a central opening the peripheral portion of which is hermetically sealed to said housing at the open end of said cavity, and means for supplying a fluid lubricant to said thrust bearing, said thrust bearing having a lubricant-conducting path connecting said lubricant supplying means with the space between said thrust plate and collar intermediate the peripheries thereof, the surfaces of said plate and collar being constructed and arranged to inhibit radial flow of lubricant and, on rotation of said thrust collar, to draw lubricant through said path between the bearing surfaces and to increase the pressure therebetween and in said cavity and thereby exert a supporting force on said end portion of said shaft.

  14. Assurance of lubricant supply in wet-lubricated space bearings

    NASA Technical Reports Server (NTRS)

    Glassow, F. A.

    1976-01-01

    Conventional lubrication techniques appear to be satisfactory, but rigorous proof of meeting a ten-year life requirement is lacking. One approach provides additional lubricant only when commanded from ground control, while the other passively augments lubrication at all times. Each technique has specific advantages, and selection should be related to the application to obtain optimum performance.

  15. "Journalism, Poetry, Stand-Up Comedy, and Academic Writing: Mapping the Interplay of Curricular and Extracurricular Literate Activities": Re-Visiting a Theoretical Lens Five Years Later

    ERIC Educational Resources Information Center

    Roozen, Kevin

    2014-01-01

    Published in a 2008 issue of "Journal of Basic Writing" ("JBW"), "Journalism, Poetry, Stand-Up Comedy, and Academic Writing: Mapping the Interplay of Curricular and Extracurricular Literate Activities" was Kevin Roozen's first single-authored publication. Drawn from data collected for the first case study from…

  16. Magnetically-controlled bearing lubrication

    NASA Technical Reports Server (NTRS)

    Whitaker, A. F.

    1977-01-01

    Proposed magnetic-lubricant ball-bearing assembly has permanently-magnetized bearing retainer fabricated of porous material. Pores of retainer are filled with ferrolubricant. Surface tension causes retainer to deliver sufficient lubricant to nonmagnetic ball bearings.

  17. High-temperature bearing lubricants

    NASA Technical Reports Server (NTRS)

    Anderson, W. J.; Parker, R. J.; Zaretsky, E. V.

    1968-01-01

    Synthetic paraffinic oil lubricates ball bearings at temperatures in the 600 degrees F range. The lubricant contains antiwear and antifoam additives, is thermally stable in the high temperature range, but requires protection from oxygen.

  18. Active Management of Integrated Geothermal-CO2 Storage Reservoirs in Sedimentary Formations: Data used in Geosphere Journal Article

    DOE Data Explorer

    Thomas A. Buscheck

    2015-06-01

    This data submission is for Phase 2 of Active Management of Integrated Geothermal-CO2 Storage Reservoirs in Sedimentary Formations, which focuses on multi-fluid (CO2 and brine) geothermal energy production and diurnal bulk energy storage in geologic settings that are suitable for geologic CO2 storage. This data submission includes all data used in the Geosphere Journal article by Buscheck et al (2016). All assumptions are discussed in that article.

  19. Fluid lubricated bearing construction

    DOEpatents

    Dunning, John R.; Boorse, Henry A.; Boeker, Gilbert F.

    1976-01-01

    1. A fluid lubricated thrust bearing assembly comprising, in combination, a first bearing member having a plain bearing surface, a second bearing member having a bearing surface confronting the bearing surface of said first bearing member and provided with at least one spiral groove extending inwardly from the periphery of said second bearing member, one of said bearing members having an axial fluid-tight well, a source of fluid lubricant adjacent to the periphery of said second bearing member, and means for relatively rotating said bearing members to cause said lubricant to be drawn through said groove and to flow between said bearing surfaces, whereby a sufficient pressure is built up between said bearing surfaces and in said well to tend to separate said bearing surfaces.

  20. High-Temperature Lubricants

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In the early 1980's, Lewis Research Center began a program to develop high-temperature lubricants for use on future aircraft flying at three or more times the speed of sound, which can result in vehicle skin temperatures as high as 1,600 degrees Fahrenheit. A material that emerged from this research is a plasma-sprayed, self-lubricating metal- glass-fluoride coating able to reduce oxidation at very high temperatures. Technology is now in commercial use under the trade name Surf-Kote C-800, marketed by Hohman Plating and Manufacturing Inc. and manufactured under a patent license from NASA. Among its uses are lubrication for sliding contact bearings, shaft seals for turbopumps, piston rings for high performance compressors and hot glass processing machinery; it is also widely used in missile and space applications.

  1. Basic lubrication equations

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1981-01-01

    Lubricants, usually Newtonian fluids, are assumed to experience laminar flow. The basic equations used to describe the flow are the Navier-Stokes equation of motion. The study of hydrodynamic lubrication is, from a mathematical standpoint, the application of a reduced form of these Navier-Stokes equations in association with the continuity equation. The Reynolds equation can also be derived from first principles, provided of course that the same basic assumptions are adopted in each case. Both methods are used in deriving the Reynolds equation, and the assumptions inherent in reducing the Navier-Stokes equations are specified. Because the Reynolds equation contains viscosity and density terms and these properties depend on temperature and pressure, it is often necessary to couple the Reynolds with energy equation. The lubricant properties and the energy equation are presented. Film thickness, a parameter of the Reynolds equation, is a function of the elastic behavior of the bearing surface. The governing elasticity equation is therefore presented.

  2. Inserts Automatically Lubricate Ball Bearings

    NASA Technical Reports Server (NTRS)

    Hager, J. A.

    1983-01-01

    Inserts on ball-separator ring of ball bearings provide continuous film of lubricant on ball surfaces. Inserts are machined or molded. Small inserts in ball pockets provide steady supply of lubricant. Technique is utilized on equipment for which maintenance is often poor and lubrication interval is uncertain, such as household appliances, automobiles, and marine engines.

  3. Lubrication of rolling element bearings

    NASA Technical Reports Server (NTRS)

    Parker, R. J.

    1980-01-01

    This paper is a broad survey of the lubrication of rolling-element bearings. Emphasis is on the critical design aspects related to speed, temperature, and ambient pressure environment. Types of lubrication including grease, jets, mist, wick, and through-the-race are discussed. The paper covers the historical development, present state of technology, and the future problems of rolling-element bearing lubrication.

  4. Environmental Capability of Liquid Lubricants

    NASA Technical Reports Server (NTRS)

    Beerbower, A.

    1973-01-01

    The methods available for predicting the properties of liquid lubricants from their structural formulas are discussed. The methods make it possible to design lubricants by forecasting the results of changing the structure and to determine the limits to which liquid lubricants can cope with environmental extremes. The methods are arranged in order of their thermodynamic properties through empirical physical properties to chemical properties.

  5. Vapor/Mist Used to Lubricate Gears After Loss of Primary Lubrication System

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Morales, Wilfredo

    2001-01-01

    Loss of lubrication in rotorcraft drive systems is a demanding requirement placed on drive system manufacturers. The drive system must operate for at least 30 minutes once the primary lubrication system has failed. This test is a military requirement that must be passed prior to certification of the aircraft. As new aircraft engines, operating at higher speeds, are fielded, the requirements for the drive system become increasingly more difficult. Also, the drive system must be lightweight, which minimizes the opportunity to use the gear bodies to absorb the tremendous amount of heating that takes place. In many cases, the amount of heat generated because of the high speed and load requires an emergency lubrication system that negatively impacts the aircraft's weight, complexity, and cost. A single mesh spur gear test rig is being used at the NASA Glenn Research Center to investigate possible emergency lubrication system improvements that will minimize the impact of having these systems onboard rotorcraft. A technique currently being investigated uses a vapor/mist system to lubricate the contacting surfaces after the primary lubrication system has been shut down. A number of tests were conducted in which the vapor/mist used the same lubricant as the primary system, but at a greatly reduced flow rate. Each test was initiated with the primary lubrication system operational and at steady-state conditions for a given speed and load. Then the primary lubrication system was shut down, and the vapor/mist lubrication system was initiated. An example of the tests conducted is shown in the figures. These preliminary tests have uncovered a mechanism that provides a lubricious, carbonaceous solid on the surface that actually reduces the surface temperature of the meshing gear teeth during operation. Surface analysis of the carbonaceous solid revealed it was graphitic. This mechanism is the synthetic lubricant "coking" on the active profile of the gears, which reduces the

  6. Self-lubricating gearset

    NASA Technical Reports Server (NTRS)

    Binge, D. S.

    1981-01-01

    Gearset fabricated from molybdenum sulfide filled polyimide allows attention-free operation in vacuum and at extreme temperatures. Ring gear drives pinion gear on shaft in skewed-axis arrangement. Because loads are shared among multiple meshing teeth, self-lubricating material is strong enough to accomodate high gear ratio.

  7. Estolides: biobased lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estolides were originally developed as a cost effective derivative from vegetable oil sources to overcome the problems associated with standard vegetable oils as lubricants. Classic estolides are formed by the formation of a carbocation at the site of unsaturation that can undergo nucleophilic addi...

  8. A new solid lubricant

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.; Sliney, H. E.

    1969-01-01

    Friction and wear life studies on burnished films of the compound graphite fluoride have demonstrated its potential as a solid lubricant material. It is effective in moist air, dry air, or in dry argon at temperatures up to approximately 400 degrees C.

  9. SURFACTANTS IN LUBRICATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  10. Natural oils as lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  11. Biobased lubricant additives

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  12. Auto Mechanics: Auto Mechanic Service Specialist (Lubrication).

    ERIC Educational Resources Information Center

    Hoover, Virgil

    The unit of individualized learning activities is designed to provide training in the job skill, lubrication, for the prospective auto mechanic service specialist. The materials in the unit are divided into two sections. The developmental, or preliminary phase, for use by the instructor, includes brief descriptions of the job and of the student…

  13. Glass microsphere lubrication

    NASA Technical Reports Server (NTRS)

    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

  14. The British Dental Journal: a report on its activities 1986-1991.

    PubMed

    Murray, J J

    1992-06-20

    The contents of 139 issues of the British Dental Journal, published between January 11, 1986 and December 1991, have been analysed. Part I of the Journal contains, on average, one Leader, eleven items of news and notes, 12 letters and eight abstracts/book reviews. One thousand, three hundred and seventeen manuscripts were submitted for publication during the 6-year period. Of these, 403 original articles, 119 case reports and 203 review articles were accepted and published in Part II. Part III of the Journal is devoted to annual and other reports and policy documents, worldwide dentistry, practice management and vocational training, dental electives, trade news, meeting reports and obituaries. Over 40 'strap headings' denoting specialised areas of dentistry were used to describe articles published. Almost one-fifth of the papers were concerned with restorative dentistry. Case reports comprised 14% of the papers published. Oral surgery/oral medicine/oral pathology, and related subjects accounted for nearly 15% of papers published. Articles concerned with community dental health, orthodontics and paediatric dentistry accounted for a similar proportion of the total, as did the section comprising general dental practice, vocational training and practice management. Anaesthesia, analgesia, medical topics, microbiology and therapeutics took up 12% of articles published. The remaining 12% consisted of articles on dental education and research, oral biology, dental history, auxiliaries, dental instruments and diagnostic aids. PMID:1616771

  15. Carbon-based tribofilms from lubricating oils.

    PubMed

    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

  16. Lubrication handbook for the space industry. Part A: Solid lubricants. Part B: Liquid lubricants

    NASA Technical Reports Server (NTRS)

    Mcmurtrey, E. L.

    1985-01-01

    This handbook is intended to provide a ready reference for many of the solid and liquid lubricants used in the space industry. Lubricants and lubricant properties are arranged systematically so that designers, engineers, and maintenance personnel can conveniently locate data needed for their work. This handbook is divided into two major parts (A and B). Part A is a compilation of solid lubricant suppliers information on chemical and physical property of data of more than 250 solid lubricants, bonded solid lubricants, dispersions, and composites. Part B is a compilation of chemical and physical porperty data of more then 250 liquid lubricants, greases, oils, compounds, and fluids. The listed materials cover a broad spectrum from manufacturing and ground support to hardware applications of spacecraft.

  17. Lubricity of military jet fuels

    SciTech Connect

    Liberio, P.D.; Garver, J.M.

    1995-06-01

    In 1954, a corrosion inhibitor additive was required in JP-4, a wide cut gasoline type aviation turbine fuel, to alleviate corrosion carry-over from ground fuel systems to aircraft. The additive was blamed for fuel filtration problems and removed from the JP-4 specification in 1965. Almost immediately, the U.S. Air Force started experiencing lubricity problems with fuel pumps and controllers. Fuel controller tests showed that when a corrosion inhibitor was added to the fuel, the lubricity problem was alleviated. The effectiveness of the corrosion inhibitor additives as lubricity improvers was then studied. A variety of test methods evolved for use in evaluating the effectiveness of a corrosion inhibitor as a lubricity improver. In 1989, the ball-on-cylinder lubricity evaluator (BOCLE) test was added to MIL-I-25017, a military specification for fuel soluble corrosion inhibitor/lubricity improver, to determine lubricity effectiveness of the corrosion inhibitor additives. Since the revision of this specification, all corrosion inhibitor/lubricity improver additives on the qualified products list, QPL-25017, have been tested using the BOCLE. Due to aircraft engine redesign, MIL-T-25524, a thermally stable turbine fuel, recently required the addition of a lubricity additive. Concerns were raised to the effect that corrosion inhibitor/lubricity improver would have on the thermal stability of thermally stable turbine fuel. Recent jet fuel thermal oxidation tester and BOCLE evaluation of the additives in thermally stable turbine fuel addressed these concerns. 16 refs., 1 fig., 4 tabs.

  18. Lubrication Handbook For The Space Industry

    NASA Technical Reports Server (NTRS)

    Mcmurtrey, Ernest L.

    1988-01-01

    A 458-page handbook covers many of solid and liquid lubricants used in space industry. Also useful reference in industrial and military applications of lubricants. Part A of handbook compilation of data on chemical and physical properties of over 250 solid lubricants, including bonded solid lubricants, dispersions, and composites. Part B covers over 250 liquid lubricants, greases, oils, compounds, and fluids.

  19. Downhole cleaner assembly for cleansing lubricant of downhole turbo-machines within wells

    SciTech Connect

    Erickson, J.W.; Petrie, H.L.

    1981-04-28

    While in a well, a downhole turbo-machine of a series of turbine stages and pump stages is driven by power fluid circulated into the turbine stages from the surface. A branch stream from the power fluid passes through a centrifugal cleaner and is cleansed of solid material. The turbine stages drive the centrifugal cleaner. The cleansed stream becomes lubricant for the turbomachine bearings. On the turbine side, the lubricant stream passes at substantially cleaner discharge pressure into longitudinal passages between turbine shrouds and an alignment tube to journal bearings and journals located between turbine stage stators and a drive shaft driven by the turbines. Annular channels between separate shrouds effect communication between the longitudinal passages between the shrouds and the alignment tube. On the pump side, the lubricant stream is first directed so that it can act on a thrust bearing runner and apply a force in opposition to an otherwise unbalanced axial force. A low pressure discharge from the thrust bearing runner supplies galleries that feed journal and journal bearings of the pump stage stators. Gallery pressure is maintained positive with respect to the pump stage bearings by a feed to the gallery in excess of bleed-out of the bearings. A check valve relieves any excess gallery pressure to that of the next to the last turbine stage fluid passage. Lubricant bleeds from the journals and journal bearings into the fluid stream passing through the turbine pumps.

  20. Crankshaft supporting and lubricating structure for multicylinder internal combustion engines

    SciTech Connect

    Anno, N.

    1987-04-14

    This patent describes a crankshaft supporting and lubricating device in a multicylinder internal combustion engine having bearing caps secured to journal walls of a cylinder block rotatably supporting a crankshaft between the bearing caps and the journal walls with a bridge interconnecting the bearing caps. The improvement described here comprises: the bearing caps and the bridge having branch oil passages defined therein for supplying lubricating oil to bearings of the crankshaft; the branch oil passages being deviated to one side from a cylinder axis passing through the center of the crankshaft; the bridge having a main gallery defined therein in communication with the branch oil passages and also deviated to the one side; and the bridge and one of the bearing caps having an oil passage defined therein on the one side and providing communication between the main gallery and a pressurized oil source.

  1. Synthesis of new high performance lubricants and solid lubricants

    SciTech Connect

    Lagow, R.J.

    1992-03-01

    We have started to make a number of classes of new perfluoropolyethers both in the solid lubricant area and liquid lubricant area. We have prepared some chlorofluoroethers for testing as additives for normal petroleum and polyalphaolefin lubricants which are so widely used in the United States. Perfluoropolyethers are not soluble in hydrocarbons. On the other hand, these chlorofluoropolyethers are soluble in substantial amounts in simple hydrocarbons. These are uniquely capable of being additives that flow with the motor oil or the polyalphaolefin.

  2. 41 CFR 101-26.602-1 - Procurement of lubricating oils, greases, and gear lubricants.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  3. 41 CFR 101-26.602-1 - Procurement of lubricating oils, greases, and gear lubricants.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  4. 41 CFR 101-26.602-1 - Procurement of lubricating oils, greases, and gear lubricants.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  5. 41 CFR 101-26.602-1 - Procurement of lubricating oils, greases, and gear lubricants.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  6. 41 CFR 101-26.602-1 - Procurement of lubricating oils, greases, and gear lubricants.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  7. Lubrication of space systems

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    1994-01-01

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

  8. Shearing stability of lubricants

    NASA Technical Reports Server (NTRS)

    Shiba, Y.; Gijyutsu, G.

    1984-01-01

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

  9. HRD Journals.

    ERIC Educational Resources Information Center

    1996

    This document consists of four papers presented during a symposium on human resource development (HRD) journals moderated by Peter W.J. Schramade at the 1996 conference of the Academy of Human Resource Development. "Refereed Journals: The Cornerstone of a Developing Profession" (Gary N. McLean) describes the purpose, format, success, and…

  10. Journalism Forum.

    ERIC Educational Resources Information Center

    Reddick, David B.; Lehnert, Eileen; And Others

    1980-01-01

    Contains five short discussions on the following topics: (1) using precision journalism techniques, (2) coping with teacher evaluation, (3) a program in which journalism students help produce a Sunday newspaper edition, (4) a course in international mass communications, and (5) professional journalists' opinions of the content of master's…

  11. New Journalism.

    ERIC Educational Resources Information Center

    Fishwick, Marshall, Ed.

    This volume contains a selection of articles which examine, critique, and help to define the phenomenon of new journalism. Included are "Popular Culture and the New Journalism" (Marshall Fishwick), "Entrance" (Richard A. Kallan), "How 'New'?" (George A. Hough III), "Journalistic Primitivism" (Everette E. Dennis), "Wherein Lies the Value?" (Michael…

  12. Fault lubrication during earthquakes.

    PubMed

    Di Toro, G; Han, R; Hirose, T; De Paola, N; Nielsen, S; Mizoguchi, K; Ferri, F; Cocco, M; Shimamoto, T

    2011-03-24

    The determination of rock friction at seismic slip rates (about 1 m s(-1)) is of paramount importance in earthquake mechanics, as fault friction controls the stress drop, the mechanical work and the frictional heat generated during slip. Given the difficulty in determining friction by seismological methods, elucidating constraints are derived from experimental studies. Here we review a large set of published and unpublished experiments (∼300) performed in rotary shear apparatus at slip rates of 0.1-2.6 m s(-1). The experiments indicate a significant decrease in friction (of up to one order of magnitude), which we term fault lubrication, both for cohesive (silicate-built, quartz-built and carbonate-built) rocks and non-cohesive rocks (clay-rich, anhydrite, gypsum and dolomite gouges) typical of crustal seismogenic sources. The available mechanical work and the associated temperature rise in the slipping zone trigger a number of physicochemical processes (gelification, decarbonation and dehydration reactions, melting and so on) whose products are responsible for fault lubrication. The similarity between (1) experimental and natural fault products and (2) mechanical work measures resulting from these laboratory experiments and seismological estimates suggests that it is reasonable to extrapolate experimental data to conditions typical of earthquake nucleation depths (7-15 km). It seems that faults are lubricated during earthquakes, irrespective of the fault rock composition and of the specific weakening mechanism involved. PMID:21430777

  13. Ball Bearings Equipped for In Situ Lubrication on Demand

    NASA Technical Reports Server (NTRS)

    Marchetti, Mario; Jones, William R., Jr.; Pepper, Stephen V.; Jansen, Mark; Predmore, Roamer

    2005-01-01

    In situ systems that provide fresh lubricants to ball/race contacts on demand have been developed to prolong the operational lives of ball bearings. These systems were originally intended to be incorporated into ball bearings in mechanisms that are required to operate in outer space for years, in conditions in which lubricants tend to deteriorate and/or evaporate. These systems may also be useful for similarly prolonging bearing lifetimes on Earth. Reservoirs have been among the means used previously to resupply lubricants. Lubricant- resupply reservoirs are bulky and add complexity to bearing assemblies. In addition, such a reservoir cannot be turned on or off as needed: it supplies lubricant continuously, often leading to an excess of lubricant in the bearing. A lubricator of the present type includes a porous ring cartridge attached to the inner or the outer ring of a ball bearing (see Figure 1). Oil is stored in the porous cartridge and is released by heating the cartridge: Because the thermal expansion of the oil exceeds that of the cartridge, heating causes the ejection of some oil. A metal film can be deposited on a face of the cartridge to serve as an electrical-resistance heater. The heater can be activated in response to a measured increase in torque that signals depletion of oil from the bearing/race contacts. Because the oil has low surface tension and readily wets the bearing-ring material, it spreads over the bearing ring and eventually reaches the ball/race contacts. The Marangoni effect (a surface-tension gradient associated with a temperature gradient) is utilized to enhance the desired transfer of lubricant to the ball/race contacts during heating. For a test, a ball bearing designed for use at low speed was assembled without lubricant and equipped with a porous-ring lubricator, the resistance heater of which consumed a power of less than 1 W when triggered on by a torque-measuring device. In the test, a load of 20 lb (.89 N) was applied and the

  14. Lubrication handbook for use in the space industry. Part A: Solid lubricants. Part B: Liquid lubricants

    NASA Technical Reports Server (NTRS)

    Campbell, M. E.; Thompson, M. B.

    1972-01-01

    This handbook provides a ready reference for many of the solid and liquid lubricants used in the space industry. Lubricants and lubricant properties are arranged systematically so that designers, engineers, and maintenance personnel in the space industry can conveniently locate data needed for their work. The handbook is divided into two major parts. Part A is a compilation of chemical and physical property data of more than 250 solid lubricants, bonded solid lubricants, dispersions and composites. Part B is a compilation of chemical and physical property data of more than 250 liquid lubricants, greases, oils, compounds and fluids. The listed materials cover a broad spectrum, from manufacturing and ground support to hardware applications for missiles and spacecraft.

  15. Two High-Temperature Foil Journal Bearings

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    2006-01-01

    An enlarged, high-temperature-compliant foil bearing has been built and tested to demonstrate the feasibility of such bearings for use in aircraft gas turbine engines. Foil bearings are attractive for use in some machines in which (1) speeds of rotation, temperatures, or both exceed maximum allowable values for rolling-element bearings; (2) conventional lubricants decompose at high operating temperatures; and/or (3) it is necessary or desirable not to rely on conventional lubrication systems. In a foil bearing, the lubricant is the working fluid (e.g., air or a mixture of combustion gases) in the space between the journal and the shaft in the machine in which the bearing is installed.

  16. Process for preparing lubricating oil from used waste lubricating oil

    DOEpatents

    Whisman, Marvin L.; Reynolds, James W.; Goetzinger, John W.; Cotton, Faye O.

    1978-01-01

    A re-refining process is described by which high-quality finished lubricating oils are prepared from used waste lubricating and crankcase oils. The used oils are stripped of water and low-boiling contaminants by vacuum distillation and then dissolved in a solvent of 1-butanol, 2-propanol and methylethyl ketone, which precipitates a sludge containing most of the solid and liquid contaminants, unspent additives, and oxidation products present in the used oil. After separating the purified oil-solvent mixture from the sludge and recovering the solvent for recycling, the purified oil is preferably fractional vacuum-distilled, forming lubricating oil distillate fractions which are then decolorized and deodorized to prepare blending stocks. The blending stocks are blended to obtain a lubricating oil base of appropriate viscosity before being mixed with an appropriate additive package to form the finished lubricating oil product.

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

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  18. Carbon-based tribofilms from lubricating oils

    NASA Astrophysics Data System (ADS)

    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.

  19. Evaluating Solid-Lubricant Films

    NASA Technical Reports Server (NTRS)

    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.

  20. Engine sealing and lubrication systems

    NASA Technical Reports Server (NTRS)

    Zuk, J.

    1975-01-01

    Engine sealing programs are discussed which are directed toward the two major classes of engine seals: engine shaft seals and primary gas path seals. In addition, some concepts and results from fundamental lubrication research, as it pertains to the lubrication of bearings, are presented.

  1. Air-Lubricated Lead Screw

    NASA Technical Reports Server (NTRS)

    Perkins, G. S.

    1983-01-01

    Air lubricated lead screw and nut carefully machined to have closely matched closely fitting threads. Compressed air injected into two plenums encircle nut and flow through orifices to lubricate mating threads. Originally developed to position precisely interferometer retroreflector for airborne measurement of solar infrared radiation, device now has positioning accuracy of 0.25 micron.

  2. Elastohydrodynamic lubrication theory

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1982-01-01

    The isothermal elastohydrodynamic lubrication (EHL) of a point contact was analyzed numerically by simultaneously solving the elasticity and Reynolds equations. In the elasticity analysis the contact zone was divided into equal rectangular areas, and it was assumed that a uniform pressure was applied over each area. In the numerical analysis of the Reynolds equation, a phi analysis (where phi is equal to the pressure times the film thickness to the 3/2 power) was used to help the relaxation process. The EHL point contact analysis is applicable for the entire range of elliptical parameters and is valid for any combination of rolling and sliding within the contact.

  3. Lubricant Coating Process

    NASA Technical Reports Server (NTRS)

    1989-01-01

    "Peen Plating," a NASA developed process for applying molybdenum disulfide, is the key element of Techniblast Co.'s SURFGUARD process for applying high strength solid lubricants. The process requires two machines -- one for cleaning and one for coating. The cleaning step allows the coating to be bonded directly to the substrate to provide a better "anchor." The coating machine applies a half a micron thick coating. Then, a blast gun, using various pressures to vary peening intensities for different applications, fires high velocity "media" -- peening hammers -- ranging from plastic pellets to steel shot. Techniblast was assisted by Rural Enterprises, Inc. Coating service can be performed at either Techniblast's or a customer's facility.

  4. A moving spectral element approach to the dynamically loaded journal bearing problem

    SciTech Connect

    Gwynllyw, D.RH.; Davies, A.R.; Phillips, T.N.

    1996-02-01

    A moving spectral element method is described for solving the dynamically loaded journal bearing problem. The journal bearing geometry comprises two eccentric cylinders with a lubricant occupying the region between them. The inner cylinder (the journal) rotates and is also free to move under a time-dependent load, while the outer cylinder (the bearing) is stationary. Lubrication engineers are interested in the dependence of the minimum oil film thickness on viscosity and viscoelasticity. The numerical method is validated by comparing the paths with those generated from lubrication theory. A study of the effect the choice of cavitation model has upon the journal`s locus is made and is found to be critical. The possibility of an improved cavitation model is discussed. 17 refs., 29 figs., 3 tabs.

  5. Lubricating system for an internal combustion engine

    SciTech Connect

    Ishikawa, T.

    1988-12-27

    This patent describes a lubricating system for an internal combustion engine having at least one cylinder, crankcase, a crankshaft, a balancer shaft rotated by the crankshaft through gears, and an oil pump, comprising: a cover secured to the crankcase to form a part of the crankcase, the crankshaft being supported by a first bearing provided in the cover and by a second bearing provided in the crankcase; a first oil passage provided in the crankcase and cover and extending from an opening at a bottom of the crankcase to an inlet of the oil pump; a second oil passage provided in the cover and extending from an outlet of the oil pump to a first opening which opens to a journal of the crankshaft; a third oil passage provided in the crankshaft and extending from a second opening corresponding to the first opening to third openings which open to the first and second bearings and to connecting rods at crankpins of the crankshaft.

  6. On the Use of the Passive and Active Voice in Astrophysics Journal Papers: With Extensions to Other Languages and Other Fields.

    ERIC Educational Resources Information Center

    Tarone, Elaine; Dwyer, Sharon; Gillette, Susan; Icke, Vincent.

    1998-01-01

    A study examined frequency of active, passive verb forms in two astrophysics journal articles, finding "we" plus an active voice occurs at least as frequently as the passive. This pattern typifies a previously unidentified type of research article, the logical argument scientific paper, whose characteristics are detailed. Similar pattern is seen…

  7. Technological lubricating means: Evolution of materials and ideas

    NASA Astrophysics Data System (ADS)

    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.

  8. Succinimide lubricating oil dispersant

    SciTech Connect

    Wisotsky, M.J.; Bloch, R.; Brownwell, D.W.; Chen, F.J.; Gutierrez, A.

    1987-08-11

    A lubricating oil composition is described exhibiting improved dispersancy in both gasoline and diesel engines comprising a major amount of lubricating oil and 0.5 to 10 weight percent of a dispersant, the dispersant being prepared in a sequential process comprising the steps of: (a) in a first step reacting an oil-soluble polyolefin succinic anhydride, the olefin being a C/sub 3/ or C/sub 4/ olefin and an alkylene polyamine of the formula H/sub 2/N(CH/sub 2/)/sub n/(NH(CH/sub 2/)/sub n/)/sub m/sup -// NH/sub 2/ wherein n is 2 or 3 and m is 0 to 10, in a molar ratio of about 1.0 to 2.2 moles of polyolefin succinic anhydride per mole of polyamine, and (b) reacting the product of step (a) with dicarboxylic acid anhydride selected from the group consisting of maleic anhydride and succinic anhydride in sufficient molar proportions to provide a total mole ratio of about 2,3 to 3.0 moles of anhydride compounds per mole of polyamine.

  9. The Friction Evolution of Siliceous Rocks during High-Velocity Slip By Thermal Activated Transition from Powder Lubrication and Rolling to Gouge Melting

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Experimental analyses of the frictional strength of siliceous rocks (granite, tonalite, and diorite) sheared in a rotary apparatus in the velocity range of 0.002-1 m/s (0.3-7.1 MPa, 0.002 - 1 m/s, total slip up to 60 m) revealed that: (1) During long slip-distances (tens of m) at low to moderate velocity (< 5 cm/s) the friction coefficient evolves with a weakening-strengthening-weakening path (Fig. 1a); and (2) The dependence of the friction coefficient on the slip-velocity is non-monotonous with weakening-strengthening-weakening sections (Fig. 1b) (Reches & Lockner, 2010). In a typical run with granite (Fig. 1a), the friction coefficient dropped from a static value of 0.86 to a steady value of 0.35 after 2.5 m of slip, followed by a sharp increase to 0.5±0.1 after ~7 m that was maintained for the next 10 m. Then, the friction started to increase again at 17 m to 0.78 at ~20 m, and finally dropped rapidly to 0.4. The first weakening stage (< 2.5m) is associated with formation of cohesive gouge flakes made of mixture of partially hydrated and recrystallized fine-grained gouge (20-50 nm). The top of these flakes displayed cylindrical rolls, 1 micron in diameter, oriented normal to slip, and the macroscopic weakening correlates with the presence of abundant rolls. SEM analysis of fault surfaces at the second weakening stage (> 17m) revealed abundant melt features such as stretched melt drops, melt coating of solid grains and abundant voids in the melt matrix, contrasting with the total melt in high velocity experiments. These friction-distance curves in our granite experiments (e.g., Fig. 1a) bears a similar path of gabbro friction curve at high velocity (Hirose and Shimamoto 2005). We propose that this non-monotonous friction evolution can be explained as a phase transition from initial pulverization of the brittle stage (low velocity, low normal stress, small slip distance), that leads to powder lubrication by powder rolling, to partial-to-full melting of the

  10. 7 CFR 2902.46 - Forming lubricants.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Forming lubricants. 2902.46 Section 2902.46... Items § 2902.46 Forming lubricants. (a) Definition. Products designed to provide lubrication during... forming lubricants. By that date, Federal agencies that have the responsibility for drafting or...

  11. 7 CFR 3201.46 - Forming lubricants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Forming lubricants. 3201.46 Section 3201.46... Designated Items § 3201.46 Forming lubricants. (a) Definition. Products designed to provide lubrication... preference for qualifying biobased forming lubricants. By that date, Federal agencies that have...

  12. 7 CFR 3201.46 - Forming lubricants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Forming lubricants. 3201.46 Section 3201.46... Designated Items § 3201.46 Forming lubricants. (a) Definition. Products designed to provide lubrication... preference for qualifying biobased forming lubricants. By that date, Federal agencies that have...

  13. 7 CFR 3201.46 - Forming lubricants.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Forming lubricants. 3201.46 Section 3201.46... Designated Items § 3201.46 Forming lubricants. (a) Definition. Products designed to provide lubrication... preference for qualifying biobased forming lubricants. By that date, Federal agencies that have...

  14. Potentiometer, constant tension and lubrication device

    NASA Technical Reports Server (NTRS)

    Smith, H. J.

    1972-01-01

    Wiper assembly is described for feedback potentiometers which provides self cleaning, self lubrication, and tension within controlled limits. Each end of the assembly contains loose fitting leather pad thoroughly soaked in wiper lubricating fluid. Cleaning and lubrication of potentiometer resulting from use of lubrication soaked leather accomplishes noise free operation.

  15. Interdisciplinary Approach to Liquid Lubricant Technology

    NASA Technical Reports Server (NTRS)

    Ku, P. M. (Editor)

    1973-01-01

    The proceedings of a conference of liquid lubricant technology are presented. The subjects discussed are: (1) requirements and functions of liquid lubricants, (2) mineral oils, (3) greases, (4) theory of rheology, (5) mechanics and thermodynamics in lubrication, (6) environmental capability of liquid lubricants, and (7) wear corrosion and erosion.

  16. Automotive gear oil lubricant from soybean oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  17. Lubricant Rheology in Concentrated Contacts

    NASA Technical Reports Server (NTRS)

    Jacobson, B. O.

    1984-01-01

    Lubricant behavior in highly stressed situtations shows that a Newtonian model for lubricant rheology is insufficient for explanation of traction behavior. The oil film build up is predicted by using a Newtonian lubricant model except at high slide to roll ratios and at very high loads, where the nonNewtonian behavior starts to be important already outside the Hertzian contact area. Static and dynamic experiments are reported. In static experiments the pressure is applied to the lubricant more than a million times longer than in an EHD contact. Depending on the pressure-temperature history of the experiment the lubricant will become a crystallized or amorphous solid at high pressures. In dynamic experiments, the oil is in an amorphous solid state. Depending on the viscosity, time scale, elasticity of the oil and the bearing surfaces, the oil film pressure, shear strain rate and the type of lubricant, different properties of the oil are important for prediction of shear stresses in the oil. The different proposed models for the lubricant, which describe it to a Newtonian liquid, an elastic liquid, a plastic liquid and an elastic-plastic solid.

  18. Automotive Lubricant Specification and Testing

    NASA Astrophysics Data System (ADS)

    Fox, M. F.

    This chapter concerns commercial lubricant specification and testing, drawing together the many themes of previous chapters. Military lubricant standards were a very strong initial influence during World War II and led to the separate historical development of the North American and European specification systems. The wide range of functions that a successful lubricant must satisfy is discussed, together with issues of balancing special or universal applications, single or multiple engine tests, the philosophy of accelerated testing and the question of 'who sets the standards?' The role of engine tests and testing organisations is examined.

  19. Solid Lubrication Fundamentals and Applications

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2001-01-01

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

  20. Lubricant effects on bearing life

    NASA Technical Reports Server (NTRS)

    Zaretsky, Erwin V.

    1986-01-01

    Lubricant considerations for rolling-element bearings have within the last two decades taken on added importance in the design and operation of mechanical systems. The phenomenon which limits the useful life of bearings is rolling-element or surface pitting fatigue. The elastohydrodynamic (EHD) film thickness which separates the ball or roller surface from those of the raceways of the bearing directly affects bearing life. Chemical additives added to the lubricant can also significantly affect bearings life and reliability. The interaction of these physical and chemical effects is important to the design engineer and user of these systems. Design methods and lubricant selection for rolling-element bearings are presented and discussed.

  1. Investigations of lubricant rheology as applied to elastohydrodynamic lubrication

    NASA Technical Reports Server (NTRS)

    Carlson, S.; Turchina, V.; Jakobsen, J.; Sanborn, D. M.; Winer, W. O.

    1973-01-01

    The pressure viscometer was modified to permit the measurement of viscosity at elevated pressures and shear stresses up to 5 x 10 to the 6th power N/sq m (720 psi). This shear stress is within a factor of three of the shear stress occurring in a sliding ehd point contact such as occurs in the ehd simulator. Viscosity data were taken on five lubricant samples, and it was found that viscous heating effects on the viscosity were predominant and not non-Newtonian behavior at the high shear stresses. The development of the infrared temperature measuring technique for the ehd simulator was completed, and temperature data for a set of operating conditions and one lubricant are reported. The numerical analysis of the behavior of nonlinear lubricants in the lubrication of rollers is reported.

  2. Piezoviscosity In Lubrication Of Nonconformal Contacts

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    Developments in theory of lubrication. Analysis of piezoviscous-rigid regime of lubrication of two ellipsoidal contacts. Begins with Reynolds equation for point contact. Equation nondimensionalized using Roelands empirical formula and Dowson and Higginson formula. Equation solved numerically. Solutions obtained for full spectrum of conditions to find effects of dimensionless load, speed, parameters of lubricated and lubricating materials, and angle between direction of rolling and direction of entrainment of lubricant.

  3. Support of Oil Lubrication by Bonded Coatings

    NASA Technical Reports Server (NTRS)

    Holinski, R.

    1984-01-01

    A new generation of lubricating lacquers for treatment of metal surfaces has been developed. These coatings have proved to be oil-compatible and are used in oil-lubricated systems. The oil lubrication is supported thereby through reduction of friction and increase of load-carrying capacity during boundary conditions. For difficult tribological systems, the problem-solving lubricating concept has proved to be the beneficial combination of lubricating oil and bonded coatings. A number of practical applications are presented.

  4. EVIDENCE THAT MICROORGANISMS CAUSE INACTIVATION OF VIRUSES IN ACTIVATED SLUDGE (JOURNAL VERSION)

    EPA Science Inventory

    Virus loss in activated sludge appeared to be caused by microorganisms. This conclusion is supported by the finding that poliovirus infectivity decreased during incubation in mixed-liquor suspended solids, primarily because of a sedimentable, heat-sensitive component. Furthermore...

  5. Journalism Forum

    ERIC Educational Resources Information Center

    Journalism Educator, 1985

    1985-01-01

    Includes (1) survey results indicating value of traditional journalism and mass communication research; (2) survey results indicating knowledge of grammar, economics, and government are journalists' most valuable resources; (3) methods for teaching listening skills; (4) suggestions for giving public relations students an overview online services;…

  6. Ecosystem Journalism

    ERIC Educational Resources Information Center

    Robertson, Amy; Mahlin, Kathryn

    2005-01-01

    If the organisms in a prairie ecosystem created a newspaper, what would it look like? What important news topics of the ecosystem would the organisms want to discuss? Imaginative and enthusiastic third-grade students were busy pondering these questions as they tried their hands at "ecosystem journalism." The class had recently completed a study of…

  7. Electrostatic potentials of some dibenzo-p-dioxins in relation to their biological activities (journal version)

    SciTech Connect

    Murray, J.S.; Politzer, P.

    1987-01-01

    A computational analysis of the electrostatic potentials of eight halogenated dibenzo-p-dioxins was carried out at the ab initio SCF STO-5G level. It focuses upon the relationships between these potentials and the biological activities of the molecules, including toxicity, aryl hydrocarbon hydroxylase induction and receptor binding. In general, regions of negative potential are found to be associated with the oxygens and with the halogen substituents. Biological activity appears to be related to the presence of an optimum range of negative potentials above the lateral portions of the molecules in conjunction with a weakening of those near the oxygens.

  8. Journal Production and Journal Impact Factors.

    ERIC Educational Resources Information Center

    Rousseau, Ronald; Van Hooydonk, Guido

    1996-01-01

    Describes a direct linear relation between the number of articles in a journal and the journal's impact factor. Hypotheses are presented; theoretical considerations are discussed; and results are described that show exceptions for review journals and translation journals, as well as for journals in mathematics and chemistry. (Author/LRW)

  9. Structural lubricity under ambient conditions

    PubMed Central

    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

  10. Elastohydrodynamic lubrication of smooth surfaces

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.

    1983-01-01

    Fully flooded, elastohydrodynamically lubricated contacts are considered. Elastohydrodynamic lubrication (EHL) analysis requires the simultaneous solution of the elastically, viscosity, density, and Reynolds equations. The most important practical aspect of elastohydrodynamic lubrication theory is the determination of the minimum film thickness within the conjunction. The maintenance of a fluid film of adequate magnitude is an essential feature of the correct operation of lubricated machine elements. The results show the influence of contact geometry on minimum film thickness as expressed by the ellipticity parameter and the dimensionless speed, load, and materials parameters. Film thickness equations are developed for materials of high elastic modulus, such as metal, and for materials of low elastic modulus, such as rubber.

  11. Aviation-fuel lubricity evaluation

    SciTech Connect

    Not Available

    1988-07-01

    Fuel-system components have experienced problems with the slipperiness or lubricity of the fuel back to the early 1960's. As a consequence of the level of refinement necessary for the PWA 523 fuel (now designated MIL-T-38219 grade JP-7) to obtain its high-temperature stability, many of the polar compounds contributing to lubricity had been removed, resulting in abnormal hydraulic fuel-pump wear. A lubricity-enhancing compound was developed (PWA 536) to eliminate the wear problem. High-pressure piston-type fuel pumps were one of the first parts of the engine fuel system to exhibit problems related to fuel properties. One early problem manifested itself as corrosion of silver-plated slipper pads and was related to carryover of residual-chlorides fuel. Fuel controls were another part of the engine fuel system susceptible to fuel properties. Lack of lubricity agents caused fuel control sliding servo valves to stick.

  12. GENETIC ACTIVITY PROFILES AND PATTERN RECOGNITION IN TEST BATTERY SELECTION (JOURNAL VERSION)

    EPA Science Inventory

    Computer-generated genetic activity profiles and pairwise matching procedures may aid in the selection of the most appropriate short-term bioassays to be used in test batteries for the evaluation of the genotoxicity of a given chemical or group of chemicals. Selection of test bat...

  13. ELECTROSTATIC POTENTIALS OF SOME DIBENZO-P-DIOXINS IN RELATION TO THEIR BIOLOGICAL ACTIVITIES (JOURNAL VERSION)

    EPA Science Inventory

    A computational analysis of the electrostatic potentials of eight halogenated dibenzo-p-dioxins has been carried out at the ab initio SCF STO-5G level. It focuses upon the relationships between these potentials and the biological activities of the molecules, including toxicity, a...

  14. Method for lubricating contacting surfaces

    DOEpatents

    Dugger, Michael T.; Ohlhausen, James A.; Asay, David B.; Kim, Seong H.

    2011-12-06

    A method is provided for tribological lubrication of sliding contact surfaces, where two surfaces are in contact and in motion relative to each other, operating in a vapor-phase environment containing at least one alcohol compound at a concentration sufficiently high to provide one monolayer of coverage on at least one of the surfaces, where the alcohol compound continuously reacts at the surface to provide lubrication.

  15. Some new evidence on human joint lubrication.

    PubMed Central

    Unsworth, A; Dowson, D; Wright, V

    1975-01-01

    Theoretical consideration has been given to the use of pendulum machines which are used to examine the frictional properties of human joints by incorporating them as fulcra. As a result, a new type of pendulum machine has been built which incorporates the facility to apply sudden loads to the joint on starting the swinging motion, and also the ability to measure directly the frictional torque experienced by the joint. The results obtained from natural hip joints indicate the presence of squeeze film lubrication under conditions of sudden loading of a joint. In addition, a self-generated fluid film process was observed at low loads while at higher loads boundary lubrication appeared to be important. These results have been used to describe the lubrication regimens occurring in a normal activity such as walking. A single experiment carried out on a hip from a patient suffering from severe rheumatoid arthritis has also been reported and the frictional resistance was seen to be increased fifteenfold compared to a normal hip. Images PMID:1190847

  16. RET/PTC activation in papillary thyroid carcinoma: European Journal of Endocrinology Prize Lecture.

    PubMed

    Santoro, Massimo; Melillo, Rosa Marina; Fusco, Alfredo

    2006-11-01

    Papillary thyroid carcinoma (PTC) is frequently associated with RET gene rearrangements that generate the so-called RET/PTC oncogenes. In this review, we examine the data about the mechanisms of thyroid cell transformation, activation of downstream signal transduction pathways and modulation of gene expression induced by RET/PTC. These findings have advanced our understanding of the processes underlying PTC formation and provide the basis for novel therapeutic approaches to this disease. PMID:17062879

  17. The Effect of Journal Roughness and Foil Coatings on the Performance of Heavily Loaded Foil Air Bearings

    NASA Technical Reports Server (NTRS)

    Radil, Kevin C.; DellaCorte, Christopher

    2001-01-01

    Foil air bearing load capacity tests were conducted to investigate if a solid lubricant coating applied to the surface of the bearing's top foil can function as a break-in coating. Two foil coating materials, a conventional soft polymer film (polyimide) and a hard ceramic (alumina), were independently evaluated against as-ground and worn (run-in) journals coated with NASA PS304, a high-temperature solid lubricant composite coating. The foil coatings were evaluated at journal rotational speeds of 30,000 rpm and at 25 C. Tests were also performed on a foil bearing with a bare (uncoated) nickel-based superalloy top foil to establish a baseline for comparison. The test results indicate that the presence of a top foil solid lubricant coating is effective at increasing the load capacity performance of the foil bearing. Compared to the uncoated baseline, the addition of the soft polymer coating on the top foil increased the bearing load coefficient by 120% when operating against an as-ground journal surface and 85 percent against a run-in journal surface. The alumina coating increased the load coefficient by 40% against the as-ground journal but did not have any affect when the bearing was operated with the run-in journal. The results suggest that the addition of solid lubricant films provide added lubrication when the air film is marginal indicating that as the load capacity is approached foil air bearings transition from hydrodynamic to mixed and boundary lubrication.

  18. Lubricating properties of molybdenum disulfide. Part 3: Performance of molybdenum disulfide-containing oils in fluid lubrication

    NASA Technical Reports Server (NTRS)

    Soda, Norimune; Miyahara, Yoshinori

    1988-01-01

    The lubricating properties of a straight mineral oil with and without MoS2 powder were studied. Bearing testers of thrust-collar type and of journal bearing type were used for thin- and fluid-film conditions, respectively. The effectiveness of the MoS2 powder in the oil differed depending on the conditions of the rubbing surfaces. For fluid film conditions, considerable effects of the MoS2 were observed, in contrast to the thin-film cases. The addition of MoS2 powder was effective only when the lubricant film was formed between surfaces thickly enough to allow the inflow of MoS2 particles.

  19. Solid Lubrication Fundamentals and Applications: Introduction and Background. Revision 1

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1998-01-01

    This chapter presents an introduction and historical background to the field of tribology, especially solid lubrication and lubricants and sets them in the perspective of techniques and materials in lubrication. Also, solid and liquid lubrication films are defined and described.

  20. Solid Lubrication Fundamentals and Applications. Chapter 1; Introduction and Background

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1996-01-01

    This chapter presents an introduction and historical background to the field of tribology, especially solid lubrication and lubricants and sets them in the perspective of techniques and materials in lubrication. Also, solid and liquid lubrication films are defined and described.

  1. Equations For Elastohydrodynamic Lubrication Of Bearings

    NASA Technical Reports Server (NTRS)

    Zaretsky, Erwin V.

    1993-01-01

    Equation for thickness of elastohydrodynamic (EHD) lubricant film in rolling-element bearing reduced to simplified form involving only inside and outside diameters of bearing, speed of rotation, parameter related to type of lubricant, and viscosity of lubricant at temperature of bearing. In addition, experimentally derived graph of EHD-film-thickness-reduction factor as function of contact-lubricant-flow number. Accounts for lubricant starvation within Hertzian contact. Graph relating ratio of minimum film thickness to composite roughness of bearing surfaces and to lubrication-life correction factor also provided. Life-correction factor used to determine resultant life of bearing.

  2. Tribological Behavior of Aqueous Copolymer Lubricant in Mixed Lubrication Regime.

    PubMed

    Ta, Thi D; Tieu, A Kiet; Zhu, Hongtao; Zhu, Qiang; Kosasih, Prabouno B; Zhang, Jie; Deng, Guanyu

    2016-03-01

    Although a number of experiments have been attempted to investigate the lubrication of aqueous copolymer lubricant, which is applied widely in metalworking operations, a comprehensive theoretical investigation at atomistic level is still lacking. This study addresses the influence of loading pressure and copolymer concentration on the structural properties and tribological performance of aqueous copolymer solution of poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) (PPO-PEO-PPO) at mixed lubrication using a molecular dynamic (MD) simulation. An effective interfacial potential, which has been derived from density functional theory (DFT) calculations, was employed for the interactions between the fluid's molecules and iron surface. The simulation results have indicated that the triblock copolymer is physisorption on iron surface. Under confinement by iron surfaces, the copolymer molecules form lamellar structure in aqueous solution and behave differently from its bulk state. The lubrication performance of aqueous copolymer lubricant increases with concentration, but the friction reduction is insignificant at high loading pressure. Additionally, the plastic deformation of asperity is dependent on both copolymer concentration and loading pressure, and the wear behavior shows a linear dependence of friction force on the number of transferred atoms between contacting asperities. PMID:26828119

  3. Engine lubrication circuit including two pumps

    DOEpatents

    Lane, William H.

    2006-10-03

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

  4. Spectroscopic Analysis of Perfluoropolyether Lubricant Degradation During Boundary Lubrication

    NASA Technical Reports Server (NTRS)

    Herrera-Fierro, Pilar; Shogrin, Bradley A.; Jones, William R., Jr.

    1996-01-01

    The degradation of a branched perfluoropolyether (PFPE) under boundary lubrication conditions was studied using mu-FTIR and mu-Raman spectroscopies. Stainless steel (440C) discs coated with thin (600A), uniform films of the PFPE were tested in a ball-on-disc apparatus until various levels of friction coefficient were attained. Discs were then examined using the above techniques. When the friction coefficient surpassed the value obtained with an un-lubricated control, the lubricant film had either been physically displaced or partially transformed in to a 'friction polymer'. Infrared analysis of this 'friction polymer' indicated the presence of a polymeric fluorinated acid species (R(sub f)COOH). Raman spectroscopy indicated the presence of amorphous carbon in the wear track and in the friction polymer. Some reaction mechanisms are suggested to explain the results.

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

    SciTech Connect

    Qu, J.; Viola, M. B.

    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.

  6. Cost-Cutting Powdered Lubricant

    NASA Technical Reports Server (NTRS)

    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.

  7. Top-of-Rail lubricant

    SciTech Connect

    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.

  8. 14 CFR 33.39 - Lubrication system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... operate. In wet sump engines, this requirement must be met when only one-half of the maximum lubricant... allow installing a means of cooling the lubricant. (c) The crankcase must be vented to the atmosphere...

  9. 14 CFR 33.39 - Lubrication system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... operate. In wet sump engines, this requirement must be met when only one-half of the maximum lubricant... allow installing a means of cooling the lubricant. (c) The crankcase must be vented to the atmosphere...

  10. 14 CFR 33.39 - Lubrication system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... operate. In wet sump engines, this requirement must be met when only one-half of the maximum lubricant... allow installing a means of cooling the lubricant. (c) The crankcase must be vented to the atmosphere...

  11. 14 CFR 33.39 - Lubrication system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... operate. In wet sump engines, this requirement must be met when only one-half of the maximum lubricant... allow installing a means of cooling the lubricant. (c) The crankcase must be vented to the atmosphere...

  12. Method For Testing Properties Of Corrosive Lubricants

    DOEpatents

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

    2006-01-03

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

  13. Metalworking corrosion inhibition/drawing lubricant

    SciTech Connect

    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.

  14. Sputtered silver films to improve chromium carbide based solid lubricant coatings for use to 900 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Sliney, Harold E.; Deadmore, Daniel L.

    1988-01-01

    Thin silver films, 250 to 3500 A thick, were sputtered onto PS200, a plasma sprayed, chromium carbide based solid lubricant coating, to reduce run-in wear and improve tribological properties. The coating contains bonded chromium carbide as the wear resistant base stock with silver and barium fluoride/calcium fluoride eutectic added as low and high temperature lubricants, respectively. Potential applications for the PS200 coating are cylinder wall/piston ring lubrication for Stirling engines and foil bearing journal lubrication. In this preliminary program, the silver film overlay thickness was optimized based on tests using a pin-on-disk tribometer. The friction and wear studies were performed in a helium atmosphere at temperatures from 25 to 760 C with a sliding velocity of 2.7 m/s under a 4.9 N load. Films between 1000 and 1500 A provide the best lubrication of the counterface material. The films enrich the sliding surface with lubricant and reduce the initial abrasiveness of the as ground, plasma-sprayed coating surface, thus reducing wear.

  15. Sputtered silver films to improve chromium carbide based solid lubricant coatings for use to 900 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Sliney, Harold E.; Deadmore, Daniel L.

    1988-01-01

    Thin silver films, 250 to 3500 A thick, were sputtered onto PS200, a plasma sprayed, chromium carbide based solid lubricant coating, to reduce run-in wear and improve tribological properties. The coating contains bonded chromium carbide as the wear resistant base stock with silver and barium fluoride/calcium fluoride eutectic added as low and high temperature lubricants respectively. Potential applications for the PS200 coating are cylinder wall/piston ring lubrication for Stirling engines and foil bearing journal lubrication. In this preliminary program, the silver film overlay thickness was optimized based on tests using a pin-on-disk tribometer. The friction and wear studies were performed in a helium atmosphere at temperatures from 25 to 760 C with a sliding velocity of 2.7 m/s under a 4.9 N load. Films between 1000 and 1500 A provide the best lubrication of the counterface material. The films enrich the sliding surface with lubricant and reduce the initial abrasiveness of the as ground, plasma-sprayed coating surface, thus reducing wear.

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

    NASA Technical Reports Server (NTRS)

    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.

  17. Lubricants and Their Environmental Impact

    NASA Astrophysics Data System (ADS)

    Betton, C. I.

    Environmental considerations have increased in importance in the last two decades and lubricants are part of that. The REACH Regulations apply to the components of lubricants. About 50% of a lubricant can be reclaimed using refining processes ranging from acid/clay treatment through to distillation/hydrogenation to produce up to Gp. II quality re-refined base oils. The major possible contaminants are the PAHs, which are effectively removed by optimised distillation/hydrogenation, metals, remnants of VI improvers, water and untreated acids. Sulphur contents of these base oils must be viewed differently from those of virgin mineral base oils. Certain PAHs are recognised carcinogens and pose a health and safety risk and must be controlled. The use of re-refined base oils is driven by the concept of 'sustainability', to minimise pollution and maximise the use of resources.

  18. Tethered Lubricants for Small Systems

    SciTech Connect

    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.

  19. Engineering lubrication in articular cartilage.

    PubMed

    McNary, Sean M; Athanasiou, Kyriacos A; Reddi, A Hari

    2012-04-01

    Despite continuous progress toward tissue engineering of functional articular cartilage, significant challenges still remain. Advances in morphogens, stem cells, and scaffolds have resulted in enhancement of the bulk mechanical properties of engineered constructs, but little attention has been paid to the surface mechanical properties. In the near future, engineered tissues will be able to withstand and support the physiological compressive and tensile forces in weight-bearing synovial joints such as the knee. However, there is an increasing realization that these tissue-engineered cartilage constructs will fail without the optimal frictional and wear properties present in native articular cartilage. These characteristics are critical to smooth, pain-free joint articulation and a long-lasting, durable cartilage surface. To achieve optimal tribological properties, engineered cartilage therapies will need to incorporate approaches and methods for functional lubrication. Steady progress in cartilage lubrication in native tissues has pushed the pendulum and warranted a shift in the articular cartilage tissue-engineering paradigm. Engineered tissues should be designed and developed to possess both tribological and mechanical properties mirroring natural cartilage. In this article, an overview of the biology and engineering of articular cartilage structure and cartilage lubrication will be presented. Salient progress in lubrication treatments such as tribosupplementation, pharmacological, and cell-based therapies will be covered. Finally, frictional assays such as the pin-on-disk tribometer will be addressed. Knowledge related to the elements of cartilage lubrication has progressed and, thus, an opportune moment is provided to leverage these advances at a critical step in the development of mechanically and tribologically robust, biomimetic tissue-engineered cartilage. This article is intended to serve as the first stepping stone toward future studies in functional

  20. Engineering Lubrication in Articular Cartilage

    PubMed Central

    McNary, Sean M.; Athanasiou, Kyriacos A.

    2012-01-01

    Despite continuous progress toward tissue engineering of functional articular cartilage, significant challenges still remain. Advances in morphogens, stem cells, and scaffolds have resulted in enhancement of the bulk mechanical properties of engineered constructs, but little attention has been paid to the surface mechanical properties. In the near future, engineered tissues will be able to withstand and support the physiological compressive and tensile forces in weight-bearing synovial joints such as the knee. However, there is an increasing realization that these tissue-engineered cartilage constructs will fail without the optimal frictional and wear properties present in native articular cartilage. These characteristics are critical to smooth, pain-free joint articulation and a long-lasting, durable cartilage surface. To achieve optimal tribological properties, engineered cartilage therapies will need to incorporate approaches and methods for functional lubrication. Steady progress in cartilage lubrication in native tissues has pushed the pendulum and warranted a shift in the articular cartilage tissue-engineering paradigm. Engineered tissues should be designed and developed to possess both tribological and mechanical properties mirroring natural cartilage. In this article, an overview of the biology and engineering of articular cartilage structure and cartilage lubrication will be presented. Salient progress in lubrication treatments such as tribosupplementation, pharmacological, and cell-based therapies will be covered. Finally, frictional assays such as the pin-on-disk tribometer will be addressed. Knowledge related to the elements of cartilage lubrication has progressed and, thus, an opportune moment is provided to leverage these advances at a critical step in the development of mechanically and tribologically robust, biomimetic tissue-engineered cartilage. This article is intended to serve as the first stepping stone toward future studies in functional

  1. Research on Liquid Lubricants for Space Mechanisms

    NASA Technical Reports Server (NTRS)

    Jones, William R., Jr.; Shogrin, Bradley A.; Jansen, Mark J.

    1999-01-01

    Four research areas at the NASA Glenn Research Center involving the tribology of space mechanisms are highlighted. These areas include: soluble boundary lubrication additives for perfluoropolyether liquid lubricants, a Pennzane dewetting phenomenon, the effect of ODC-free bearing cleaning processes on bearing lifetimes and the development of a new class of liquid lubricants based on silahydrocarbons.

  2. Lubrication of rolling-element bearings

    NASA Technical Reports Server (NTRS)

    Parker, R. J.

    1980-01-01

    The lubrication of rolling element bearings is surveyed. Emphasis is on the critical design aspects related to speed, temperature, and ambient pressure environment. Types of lubrication including grease, jets, mist, wick, and through the race are discussed. The historical development, present state of technology, and the future problems of rolling element bearing lubrication are discussed.

  3. 21 CFR 880.6375 - Patient lubricant.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Patient lubricant. 880.6375 Section 880.6375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... § 880.6375 Patient lubricant. (a) Identification. A patient lubricant is a device intended for...

  4. New Vapor/Mist Phase Lubricant Formulated

    NASA Technical Reports Server (NTRS)

    Morales, Wilfredo; Handschuh, Robert F.

    1999-01-01

    To meet the increased thermal stresses of future advanced aircraft engines, new lubricants will have to be developed to replace the currently used ester-based liquid lubricants. If a suitable conventional replacement cannot be found, a different lubrication method will have to be used. The conventional method circulates bulk lubricant (stored in a sump) through a lubricating system containing cooling and filtering elements. Solid lubricants have been studied as a replacement for bulk liquid lubricants, and have been found to provide reasonable lubrication for lightly loaded systems. Solid lubricants, however, have proved inadequate for highly loaded, high-speed applications. Vapor/mist phase lubrication (VMPL), on the other hand, may be a viable alternative. VMPL has been used successfully to lubricate high-temperature bearings or gears. It can be used as an emergency backup system or as the primary source of lubrication. With VMPL, minimal weight is added to the system and minimal debris is formed. It works over a wide temperature range.

  5. 21 CFR 880.6375 - Patient lubricant.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Patient lubricant. 880.6375 Section 880.6375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... § 880.6375 Patient lubricant. (a) Identification. A patient lubricant is a device intended for...

  6. 21 CFR 880.6375 - Patient lubricant.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Patient lubricant. 880.6375 Section 880.6375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... § 880.6375 Patient lubricant. (a) Identification. A patient lubricant is a device intended for...

  7. Research on liquid lubricants for space mechanisms

    NASA Technical Reports Server (NTRS)

    Jones, William R., Jr.; Shogrin, Bradley A.; Jansen, Mark J.

    1998-01-01

    Four research areas at the NASA Lewis Research Center involving the tribology of space mechanisms are highlighted. These areas include: soluble boundary lubrication additives for perfluoropolyether liquid lubricants, a Pennzane dewetting phenomenon, the effect of ODC-free bearing cleaning processes on bearing lifetimes, and the development of a new class of liquid lubricants based on silahydrocarbons.

  8. 21 CFR 880.6375 - Patient lubricant.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Patient lubricant. 880.6375 Section 880.6375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... § 880.6375 Patient lubricant. (a) Identification. A patient lubricant is a device intended for...

  9. 21 CFR 880.6375 - Patient lubricant.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Patient lubricant. 880.6375 Section 880.6375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... § 880.6375 Patient lubricant. (a) Identification. A patient lubricant is a device intended for...

  10. 7 CFR 3201.38 - Firearm lubricants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Firearm lubricants. 3201.38 Section 3201.38... Designated Items § 3201.38 Firearm lubricants. (a) Definition. Lubricants that are designed for use in firearms to reduce the friction and wear between the moving parts of a firearm, and to keep the...

  11. 7 CFR 3201.38 - Firearm lubricants.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Firearm lubricants. 3201.38 Section 3201.38... Designated Items § 3201.38 Firearm lubricants. (a) Definition. Lubricants that are designed for use in firearms to reduce the friction and wear between the moving parts of a firearm, and to keep the...

  12. 7 CFR 3201.38 - Firearm lubricants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Firearm lubricants. 3201.38 Section 3201.38... Designated Items § 3201.38 Firearm lubricants. (a) Definition. Lubricants that are designed for use in firearms to reduce the friction and wear between the moving parts of a firearm, and to keep the...

  13. 14 CFR 33.71 - Lubrication system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Lubrication system. 33.71 Section 33.71 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.71 Lubrication system. (a) General. Each lubrication...

  14. Gearing up for synthetic lubricants

    SciTech Connect

    Shelley, S.

    1993-07-01

    Much of today's plant machinery operates at faster speeds, closer tolerances and higher temperatures than ever before. Without the help of lubricants to reduce wear, remove heat, and prevent corrosion, the chemical process industries would grind to a halt. Traditional, petroleum-derived products--called mineral oils-- have long starred in these roles. But today, synthetics, such as polyalphaolefins, carboxylic acid esters, phosphate esters and polyglycols are stealing the limelight, thanks to their inherent resistance to oxidation and hydrolysis and their extended range of service temperatures. The paper reviews the advantages of the synthetic lubricants.

  15. Synthesis of new high performance lubricants and solid lubricants

    SciTech Connect

    Lagow, Richard J.

    1993-04-08

    In our second year of funding we began the testing phase of a number of new classes of lubricants. Three different testing collaborations have already begun and a fourth one is In the works with Dr. Stephen Hsu of the National Institute of Standards and Technology. Dr. Hsu also plans to test some of the same materials for us that Shell Development is studying. With Dr. Bill Jones of NASA, we are studying the effects of branching an high temperature lubricant properties in perfluoropolyethers, Initially Bill Jones is comparing the lubrication and physical properties of perfluorotetraglyme and the following two spherical perfluoropolyethers, Note that one contains a fluorocarbon chain and the other one contains a fluorocarbon ether chain. The synthesis of these was reported in the last progress report. With Professor Patricia Thiel of Iowa State University, we are working on studies of perfluoromethylene oxide ethers and have prepared a series of four of these polyethers to study in collaboration with her research group. These perfluoromethylene oxide ethers have the best low temperature properties of any known lubricants. Thiel's group is studying their interactions with metals under extreme conditions. Thirdly, we have also begun an Interaction with W. August Birke of Shell Development Company in Houston for whom we have already prepared samples of the chlorine-substituted fluorocarbon polyether lubricants whose structures appear on page 54 of our research proposal. Each of these four structures is thought to have potential as lubricant additives to motor oils. We also have underway syntheses of other fluorine-containing branched ether lubricants. These new materials which are also promising as antifriction additives for motor oils appear ahead of the perfluoro additives as Appendix I to the progress report. Additionally for Birke and Shell Development we have at their request prepared the novel compound perfluoro salicylic acid. This synthesis was suggested by the

  16. The application of dichotomy in equilibrium position of journal bearing

    NASA Astrophysics Data System (ADS)

    Wu, G. K.; Luo, X. Q.

    2016-05-01

    The fluid lubricant force in the journal bearing is an important factor for the stability and dynamic characteristics of rotating machine. In order to obtain the dynamic coefficients of journal bearing, the equilibrium position must be known for further calculation. In this paper, the Reynolds equation is solved by finite difference method and the dichotomy is applied to acquire the equilibrium position of journal bearing by means of double loop. The effects of length, radius and clearance of journal bearing on the equilibrium position are also researched. The calculated results show that the dichotomy is an effective method for the equilibrium position of journal bearing and the geometry parameters play an important effect on the equilibrium position.

  17. Self lubrication of bitumen froth in pipelines

    SciTech Connect

    Joseph, D.D.

    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.

  18. What are Journals for?

    PubMed

    Rallison, S P

    2015-03-01

    'The secret is comprised in three words - work, finish, publish.' Michael Faraday There are many reasons doctors want to publish their work. For most at an early stage in their career, this may be to add a line to their curriculum vitae and advance their careers but for academics, publishing is an expectation. Many will believe they have something important to say, and wish to provoke debate and discussion; others wish to share knowledge and experiences, which in medicine can lead to a satisfying change in clinical practice. All serve to register one's idea and educate others. However, for some, the reason is as basic as money. As we celebrate the 350th anniversary of the first academic publication, perhaps we have come full circle when it comes to why people publish? Publishing is a flourishing business. There were approximately 28,100 active scholarly peer-reviewed journals in mid-2012, collectively publishing about 1.8-1.9 million articles per year. The number of articles published each year and the number of journals have both grown steadily for more than two centuries, by about 3% and 3.5% per year respectively. (1) Journals have a responsibility to refine and define information and act as a scientific filter. Many of us will receive daily invitations in our email inbox from eclectic and new journals that are likely to take anything - is the filter now too porous? But this industry is like any other commercial activity and the supply still far outstrips the demand. Perhaps the internet revolution has merely fuelled our hunger to publish more? The launch of this exciting and innovative series about publishing coincides with the 350th celebration of the publication of the first academic journal. In the age of social media, the first question is 'What are journals for?', which Simon Rallison sets out to answer. Simon is Director of Publications at the Physiological Society, and was previously a journal publisher with Earthscan, Springer and Blackwell. Writing is

  19. Thin Film Solid Lubricant Development

    NASA Technical Reports Server (NTRS)

    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.

  20. Lubricant Selection Manual, Phase 3

    NASA Technical Reports Server (NTRS)

    Kannel, J. W.; Lowry, J. A.; Dufrane, K. F.

    1991-01-01

    Future spacecraft must be designated to operate for very long time periods in space. For example, a target goal for the Space Station is 30 years of operation. Although the actual life may be significantly less than this optimistic goal, the life will certainly be a critical issue in design. The bearings on primary components such as the alpha and beta joints must obviously be designed and lubricated with the objective of optimum performance life. In addition to these joints, there will be numerous other tribological (rubbing or rolling) interfaced that will be required to function for the life of the spacecraft. A major key to adequate performance of tribological interface is proper lubrication. Lubricants can be divided into two basic classes: solid films and liquids. Both types have been used extensively in space applications. Both have advantages and disadvantages that must be carefully considered in their selection. The purpose here is to summarize selection criteria for liquid and solid lubricants applied to long-life spacecraft.

  1. Tetrasulfide extreme pressure lubricant additives

    SciTech Connect

    Gast, L.E.; Kenney, H.E.; Schwab, A.W.

    1980-08-19

    A novel class of compounds has been prepared comprising the tetrasulfides of /sup 18/C hydrocarbons, /sup 18/C fatty acids, and /sup 18/C fatty and alkyl and triglyceride esters. These tetrasulfides are useful as extreme pressure lubricant additives and show potential as replacements for sulfurized sperm whale oil.

  2. Longevity Of Dry Film Lubricants

    NASA Technical Reports Server (NTRS)

    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.

  3. Automotive Cooling and Lubricating Systems.

    ERIC Educational Resources Information Center

    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…

  4. A new journal bearing tester: The VTT water tribotester

    NASA Astrophysics Data System (ADS)

    Andersson, Peter

    1992-08-01

    The design and operation of equipment for the testing of journal bearings is described. The equipment was developed and used for the first time in a Finnish project in ceramic journal bearings. Two similar units were built in two different laboratories, one for oil and the other for water lubrication. The VIT (Technical Research Center of Finland) tribotester was designed for wide flexibility in the selection of the normal force, speed and lubricant and to make rapid test piece exchanges possible. Furthermore, the machine was designed to be easy to build, use, maintain and understand. The journal bearing to be tested has an inner diameter of 40 mm and a width of 20 mm. Exchangeable shaft bushes are used as counterpieces in the tests. The tribotester is designed for normal loads of up to 40 kN, and rotational speeds of up to 5300 rpm can be allowed. During the tests, at least the frictional force and the bearing shell temperature are continuously recorded. The wear rates are determined after a test. The first test program consisted of 22 water lubricated tests, 16 of which were performed with specimens made of monolithic ceramics and 6 with steel specimens plasma coated with ceramics. The results of the journal bearing tests are in good agreement with previous 'pin on disc' model tests. In the majority of the tests the equipment behaved as planned, and new investigations will follow.

  5. Full Life Wind Turbine Gearbox Lubricating Fluids

    SciTech Connect

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

    2012-02-28

    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.

  6. Solid Lubricants for Oil-Free Turbomachinery

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher

    2005-01-01

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

  7. High-temperature seals and lubricants for geothermal rock bits. Final report

    SciTech Connect

    Hendrickson, R.R.; Winzenried, R.W.; Jones A.H.

    1981-04-01

    High temperature seals (elastomeric and mechanical) and lubricants were developed specifically for journal-type rock bits to be used in geothermal well drilling. Results at simulated downhole conditions indicate that five selected elastomeric seals (L'Garde No. 267, Utex Nos. 227, 231 and HTCR, and Sandia Glow Discharge Coated Viton) are capable of 288/sup 0/C (500/sup 0/F) service. Two prototype mechanical seals did not achieve the life determined for the elastomeric seals. Six lubricants (Pacer PLX-024 oil, PLX-043 oil, PLX-045 oil, Geobond Oil, and Geobond Grease) demonstrated 316/sup 0/C (600/sup 0/F) capability. Recommendation is made for full-scale simulated geothermal drilling tests utilizing the improved elastomeric seals and lubricants.

  8. Flow field distribution of liquid film of water lubricated bearing-rotor coupling systems

    NASA Astrophysics Data System (ADS)

    Hu, Q. L.; Hu, J. N.; Ye, X. Y.; Zhang, D. S.; Zheng, J. B.

    2016-05-01

    According to the desalination high-pressure pump water lubricated bearing-rotor coupling systems flow field distribution of liquid film in the starting transient process and its power transmission mechanism can lay the foundation of further exploring and judging lubrication state at the boot process. By using the computational fluid dynamics Fluent secondary development platform and calling the relevant DEFINE macro function to achieve the translation and rotation movement of the journal, we will use the dynamic grid technique to realize the automatic calculation and grid update of water lubricated bearings 3d unsteady liquid film flow field, and finally we will dispose the results of numerical simulation and get the pressure. When the eccentricity is large, film thickness was negatively correlated with the pressure, and positive with the velocity. Differential pressure was negatively correlated with velocity. When the eccentricity is small, film thickness is no significant relationship with differential pressure and velocity. Differential pressure has little difference with velocity.

  9. Journaling: creating space for "I".

    PubMed

    Charles, Jennell P

    2010-01-01

    As nurses engaged in a caring profession, it is critical that we learn not only to care for others but also to care for ourselves. To care effectively for ourselves, we must create the space and time in which to do this. Journaling is one tool that scholars offer as a way to create this space. Although there is no clear consensus about the best techniques for journaling, there is evidence that journaling, as a reflective, meditative activity, can promote creativity, self-awareness, and personal development. PMID:21140872

  10. USDOE Top-of-Rail Lubricant Project

    SciTech Connect

    Mohumad F. Alzoubi; George R. Fenske; Robert A. Erck; Amrit S. Boparai

    2002-02-01

    Lubrication of wheel/rail systems has been recognized for the last two decades as a very important issue for railroads. Energy savings and less friction and wear can be realized if a lubricant can be used at the wheel/rail interface. On the other hand, adverse influences are seen in operating and wear conditions if improper or excessive lubrication is used. Also, inefficiencies in lubrication need to be avoided for economic and environmental reasons. The top-of-rail (TOR) lubricant concept was developed by Texaco Corporation to lubricate wheels and rails effectively and efficiently. Tranergy Corporation has been developing its SENTRAEN 2000{trademark} lubrication system for the last ten years, and this revolutionary new high-tech on-board rail lubrication system promises to dramatically improve the energy efficiency, performance, safety, and track environment of railroads. The system is fully computer-controlled and ensures that all of the lubricant is consumed as the end of the train passes. Lubricant quantity dispensed is a function of grade, speed, curve, and axle load. Tranergy also has its LA4000{trademark} wheel and rail simulator, a lubrication and traction testing apparatus. The primary task of this project was collecting and analyzing the volatile and semivolatile compounds produced as the lubricant was used. The volatile organic compounds were collected by Carbotrap cartridges and analyzed by adsorption and gas chromatography/mass spectrometry (GC/MS). The semivolatile fraction was obtained by collecting liquid that dripped from the test wheel. The collected material was also analyzed by GC/MS. Both of these analyses were qualitative. The results indicated that in the volatile fraction, the only compounds on the Environmental Protection Agency's (EPA) Superfund List of Analytes detected were contaminants either in the room air or from other potential contamination sources in the laboratory. Similarly, in the semivolatile fraction none of the detected