Science.gov

Sample records for air lubricated compliant

  1. 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.

  2. Hydrodynamic air lubricated compliant surface bearing for an automotive gas turbine engine. 2: Materials and coatings

    NASA Technical Reports Server (NTRS)

    Bhushan, B.; Ruscitto, D.; Gray, S.

    1978-01-01

    Material coatings for an air-lubricated, compliant journal bearing for an automotive gas turbine engine were exposed to service test temperatures of 540 C or 650 C for 300 hours, and to 10 temperature cycles from room temperatures to the service test temperatures. Selected coatings were then put on journal and partial-arc foils and tested in start-stop cycle tests at 14 kPa (2 psi) loading for 2000 cycles. Half of the test cycles were performed at a test chamber service temperature of 540 C (1000 F) or 650 C (1200 F); the other half were performed at room temperature. Based on test results, the following combinations and their service temperature limitations are recommended: HL-800 TM (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 Kaman DES on journal and foil up to 640 C (1200 F). Kaman DES coating system was further tested successfully at 35 kPa (5 psi) loading for 2000 start-stop cycles.

  3. 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.

  4. Adhesion Performance of Solid Film Lubricants on Substrates Cleaned With Environmentally Compliant Cleaners

    NASA Technical Reports Server (NTRS)

    Hall, P. B.; Thom, R. L.

    1997-01-01

    Solid film adhesion testing was used to determine the effect different environmentally compliant cleaners have on the adhesion properties of solid film lubricants used for several NASA programs. In an action to remove ozone depleting chemicals from aerospace processes, a replacement cleaner must be identified that does not affect the adhesion of solid film lubricants used on flight critical NASA hardware. ASTM D251083 Standard Test Method for Adhesion of Solid Film Lubricants was used to evaluate the cleaners. Two different lubricants - Inlox 88 and Boosterlube - were tested using various commercially available cleaners. Inlox 88 is produced by E/M Corporation and is a liquid oxygen compatible lubricant used in the Space Shuttle Main Engine, and Boosterlube is a new lubricant being implemented for use on the Space Shuttle Solid Rocket Booster. These lubricants were selected because of their specific use on flight critical NASA components. Results of this testing are presented in the paper.

  5. Experimental test program for evaluation of solid lubricant coating as applied to compliant foil gas bearings to 315 deg C

    NASA Technical Reports Server (NTRS)

    Wagner, R. C.

    1985-01-01

    An experimental apparatus and test procedure was developed to compare the performance of two solid lubricant coatings for air lubricated compliant foil gas bearings in the temperature range of 25 to 315 C. Polyimide bonded additive (SBGC) were tested extensively for durability and frictional characteristics. A partial arc bearing constructed of Inconel X-750 was coated on the bore with one of these coatings. The foil was subjected to repeated start/stop cycles. Performance comparisons reveal that although both coatings survive thousands of start/stop cycles, only the PBGF coated bearing achieves the specified 9000 start/stops. There is enough wear on the SBGC coated bearing to warrant termination of the test prior to 9000 start/stop cycles due to coating failure. The frictional characteristics of the PBGF are better at the elevated temperatures than at lower temperatures; a marked increase in sliding friction occurs as the temperature decreases. The SBGC maintains relatively constant frictional characteristics independent of operating temperature.

  6. Changes in Hardware in Order to Accommodate Compliant Foil Air Bearings of a Larger Size

    NASA Technical Reports Server (NTRS)

    Zeszotek, Michelle

    2004-01-01

    Compliant foil air bearings are at the forefront of the Oil-Free turbomachinery revolution of supporting gas turbine engines with air lubricated hydrodynamic bearings. Foil air bearings have existed for almost fifty years, yet their commercialization has been confined to relatively small, high-speed systems characterized by low temperatures and loads, such as in air cycle machines, turbocompressors and micro-turbines. Recent breakthroughs in foil air bearing design and solid lubricant coating technology, have caused a resurgence of research towards applying Oil-Free technology to more demanding applications on the scale of small and mid range aircraft gas turbine engines. In order to foster the transition of Oil-Free technology into gas turbine engines, in-house experiments need to be performed on foil air bearings to further the understanding of their complex operating principles. During my internship at NASA Glenn in the summer of 2003, a series of tests were performed to determine the internal temperature profile in a compliant bump- type foil journal air bearing operating at room temperature under various speeds and load conditions. From these tests, a temperature profile was compiled, indicating that the circumferential thermal gradients were negligible. The tests further indicated that both journal rotational speed and radial load are responsible for heat generation with speed playing a more significant role in the magnitude of the temperatures. As a result of the findings from the tests done during the summer of 2003, it was decided that further testing would need to be done, but with a bearing of a larger diameter. The bearing diameter would now be increased from two inches to three inches. All of the currently used testing apparatus was designed specifically for a bearing that was two inches in diameter. Thus, my project for the summer of 2004 was to focus specifically on the scatter shield put around the testing rig while running the bearings. Essentially

  7. Oil-air mist lubrication for helicopter gearing

    NASA Technical Reports Server (NTRS)

    Mcgrogan, F.

    1976-01-01

    The applicability of a once-through oil mist system to the lubrication of helicopter spur gears was investigated and compared to conventional jet spray lubrication. In the mist lubrication mode, cooling air was supplied at 366K (200 F) to the out of mesh location of the gear sets. The mist air was also supplied at 366K (200 F) to the radial position mist nozzle at a constant rate of 0.0632 mol/s (3 SCFM) per nozzle. The lubricant contained in the mist air varied between 32 - 44 cc/hour. In the recirculating jet spray mode, the flow rate was varied between 1893 - 2650 cc/hour. Visual inspection revealed the jet spray mode produced a superior surface finish on the gear teeth but a thermal energy survey showed a 15 - 20% increase in heat generated. The gear tooth condition in the mist lubrication mode system could be improved if the cooling air and lubricant/air flow ratio were increased. The test gearbox and the procedure used are described.

  8. An Experimental Investigation Into the Temperature Profile of a Compliant Foil Air Bearing

    NASA Technical Reports Server (NTRS)

    Radil, Kevin; Zeszotek, Michelle

    2004-01-01

    A series of tests was performed to determine the internal temperature profile in a compliant bump-type foil journal air bearing operating at room temperature under various speeds and load conditions. The temperature profile was collected by instrumenting a foil bearing with nine, type K thermocouples arranged in the center and along the bearing s edges in order to measure local temperatures and estimate thermal gradients in the axial and circumferential directions. To facilitate the measurement of maximum temperatures from viscous shearing in the air film, the thermocouples were tack welded to the backside of the bumps that were in direct contact with the top foil. The mating journal was coated with a high temperature solid lubricant that, together with the bearing, underwent high temperature start-stop cycles to produce a smooth, steady-state run-in surface. Tests were conducted at speeds from 20 to 50 krpm and loads ranging from 9 to 222 N. The results indicate that, over the conditions tested, both journal rotational speed and radial load are responsible for heat generation with speed playing a more significant role in the magnitude of the temperatures. The temperature distribution was nearly symmetric about the bearing center at 20 and 30 krpm but became slightly skewed toward one side at 40 and 50 krpm. Surprisingly, the maximum temperatures did not occur at the bearing edge where the minimum film thickness is expected but rather in the middle of the bearing where analytical investigations have predicted the air film to be much thicker. Thermal gradients were common during testing and were strongest in the axial direction from the middle of the bearing to its edges, reaching 3.78 8C/mm. The temperature profile indicated the circumferential thermal gradients were negligible.

  9. Rise of Air Bubbles in Aircraft Lubricating Oils

    NASA Technical Reports Server (NTRS)

    Robinson, J. V.

    1950-01-01

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

  10. Re-examination of compliant wall experiments in air with water substrates. [for drag reduction

    NASA Technical Reports Server (NTRS)

    Hefner, J. N.; Weinstein, L. M.

    1976-01-01

    A possible alternative explanation is proposed for compliant wall drag reductions measured in previous investigations. Standing waves were observed to form on the surfaces of compliant wall models in air with water substrates as the freestream velocity was increased from 15 to 30 m/s. These waves resembled sine waves with half of the wave protruding over the upstream portion of the model and the other half being recessed over the downstream end of the model. These data coupled with results of recent drag reduction experiments suggest that standing waves could have caused a shift in the model center of gravity creating a bending moment that was interpreted as a reduction in the skin friction drag.

  11. A review of compliant transmission mechanisms for bio-inspired flapping-wing micro air vehicles.

    PubMed

    Zhang, C; Rossi, C

    2017-02-15

    Flapping-wing micro air vehicles (FWMAVs) are a class of unmanned aircraft that imitate flight characteristics of natural organisms such as birds, bats, and insects, in order to achieve maximum flight efficiency and manoeuvrability. Designing proper mechanisms for flapping transmission is an extremely important aspect for FWMAVs. Compliant transmission mechanisms have been considered as an alternative to rigid transmission systems due to their lower the number of parts, thereby reducing the total weight, lower energy loss thanks to little or practically no friction among parts, and at the same time, being able to store and release mechanical power during the flapping cycle. In this paper, the state-of-the-art research in this field is dealt upon, highlighting open challenges and research topics. An optimization method for designing compliant transmission mechanisms inspired by the thoraxes of insects is also introduced.

  12. Leaping shampoo glides on a lubricating air layer

    NASA Astrophysics Data System (ADS)

    Lee, S.; Li, E. Q.; Marston, J. O.; Bonito, A.; Thoroddsen, S. T.

    2013-06-01

    When a stream of shampoo is fed onto a pool in one's hand, a jet can leap sideways or rebound from the liquid surface in an intriguing phenomenon known as the Kaye effect. Earlier studies have debated whether non-Newtonian effects are the underlying cause of this phenomenon, making the jet glide on top of a shear-thinning liquid layer, or whether an entrained air layer is responsible. Herein we show unambiguously that the jet slides on a lubricating air layer. We identify this layer by looking through the pool liquid and observing its rupture into fine bubbles. The resulting microbubble sizes suggest this air layer is of submicron thickness. This thickness estimate is also supported by the tangential deceleration of the jet during the rebounding.

  13. Leaping shampoo glides on a lubricating air layer.

    PubMed

    Lee, S; Li, E Q; Marston, J O; Bonito, A; Thoroddsen, S T

    2013-06-01

    When a stream of shampoo is fed onto a pool in one's hand, a jet can leap sideways or rebound from the liquid surface in an intriguing phenomenon known as the Kaye effect. Earlier studies have debated whether non-Newtonian effects are the underlying cause of this phenomenon, making the jet glide on top of a shear-thinning liquid layer, or whether an entrained air layer is responsible. Herein we show unambiguously that the jet slides on a lubricating air layer. We identify this layer by looking through the pool liquid and observing its rupture into fine bubbles. The resulting microbubble sizes suggest this air layer is of submicron thickness. This thickness estimate is also supported by the tangential deceleration of the jet during the rebounding.

  14. 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.

  15. Lubricant

    SciTech Connect

    Shubkin, R.L.

    1980-08-19

    Hydrogenated dimers of /sup 12 -18/C alpha olefins (e.g., 1-tetradecene) made using a friedel-crafts catalyst (e.g., /sup 3/Bf promoted with water) have low pour points, low volatility and viscosities which make them suitable as crankcase lubricants for internal combustion engines.

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

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  17. Failure Mechanisms of Air Entrainment in Drop Impact on Lubricated Surfaces

    NASA Astrophysics Data System (ADS)

    Pack, Min; Hu, Han; Kim, Dong-Ook; Zheng, Zhong; Stone, Howard; Sun, Ying; Drexel University Team; Princeton University Team

    2016-11-01

    Lubricated surfaces have recently been introduced and studied due to their potential benefit in various applications. Combining the techniques of total internal reflection microscopy and reflection interference microscopy, we examine the dynamics of an underlying air film upon drop impact on a lubricated substrate. In contrast to drop impact on solid surfaces where asperities cause random breakup of the entraining air film, we report two air film failure mechanisms on lubricated surfaces. In particular, using thin liquid films of high viscosity, we show that air film rupture shifts from a randomly driven to a controlled event. At low Weber numbers (We) the droplet bounces. At intermediate We, the air film fails at the center as the drop top surface crashes downward owing to impact-induced capillary waves; the resulting liquid-liquid contact time is found to be independent of We. In contrast, at high We, the air film failure occurs much earlier in time at the first inflection point of the air film shape away from the drop center, where the liquid-liquid van der Waals interactions become important. The predictable failure modes of the air film upon drop impact sheds light on droplet deposition in applications such as lubricant-infused self-cleaning surfaces. Support for this work was provided by the National Science Foundation under Grant No. CMMI-1401438 to Y.S.

  18. Next Generation Refrigeration Lubricants for Low Global Warming Potential/Low Ozone Depleting Refrigeration and Air Conditioning Systems

    SciTech Connect

    Hessell, Edward Thomas

    2013-12-31

    The goal of this project is to develop and test new synthetic lubricants that possess high compatibility with new low ozone depleting (LOD) and low global warming potential (LGWP) refrigerants and offer improved lubricity and wear protection over current lubricant technologies. The improved compatibility of the lubricants with the refrigerants, along with improved lubricating properties, will resulted in lower energy consumption and longer service life of the refrigeration systems used in residential, commercial and industrial heating, ventilating and air-conditioning (HVAC) and refrigeration equipment.

  19. Radial Clearance Found To Play a Key Role in the Performance of Compliant Foil Air Bearings

    NASA Technical Reports Server (NTRS)

    Radil, Kevin C.

    2003-01-01

    Compliant foil air bearings are at the forefront of the Oil-Free turbomachinery revolution, which supports gas turbine engines with hydrodynamic bearings that use air instead of oil as the working fluid. These types of bearings have been around for almost 50 years and have found a home in several commercial applications, such as in air cycle machines, turbocompressors, and microturbines, but are now being aggressively pursued for use in small and midrange aircraft gas turbine engines. Benefits include higher operating speeds and temperatures, lower maintenance costs, and greater reliability. The Oil-Free Turbomachinery team at the NASA Glenn Research Center is working to foster the transition of Oil-Free technology into gas turbine engines by performing in-house experiments on foil air bearings in order to gain a greater insight into their complex operating principles. A research program recently undertaken at Glenn focused on the concept of radial clearance and its influence on bearing performance. The tests were conducted on foil bearings with different radial clearances. As defined for a foil bearing, radial clearance is a measure of the small amount of shaft radial motion that is present from play that exists in the elastic support structure, such as between the top and bump foils and the bump foils and bearing shell (see the drawing). With an insufficient amount of radial clearance, the bearing imparts a high preload on the shaft, which when excessive, can reduce the loadcarrying capability of the bearing. On the other hand, systems using foil bearings with excessive radial clearance may experience rotordynamic instabilities because of low bearing preload. Therefore, without a more thorough understanding of radial clearance, it is difficult to accurately predict the performance of a given bearing design. The test program demonstrated that there is a direct correlation between radial clearance and the performance of foil air bearings. As shown in the graph, an

  20. Failure mechanisms of air entrainment in drop impact on lubricated surfaces.

    PubMed

    Pack, M; Hu, H; Kim, D; Zheng, Z; Stone, H A; Sun, Y

    2017-03-22

    Lubricated surfaces have recently been introduced and studied due to their potential benefit in various configurations and applications. Combining the techniques of total internal reflection microscopy and reflection interference microscopy, we examine the dynamics of an underlying air film upon drop impact on a lubricated substrate where the thin liquid film is immiscible to the drop. In contrast to drop impact on solid surfaces where even the smallest asperities cause random breakup of the entraining air film, we report two air film failure mechanisms on lubricated surfaces. In particular, using ≈5 μm thick liquid films of high viscosity, which should make the substrate nearly atomically smooth, we show that air film rupture shifts from asperity-driven to a controlled event. At low Weber numbers (We < 2, We = ρlU0(2)R/σ, U0 the impact velocity, R the drop radius, and ρl the density and σ the surface tension of the droplet) the droplet bounces. At intermediate We (2 < We < 10), the air film fails at the center as the top surface of the drop crashes downward owing to impact-induced capillary waves; the resulting liquid-liquid contact time is found to be independent of We. In contrast, at high We (We > 10), the air film failure occurs much earlier in time at the first inflection point of the air film shape away from the drop center, where the liquid-liquid van der Waals interactions become important. The predictable failure modes of the air film upon drop impact sheds light on droplet deposition in applications such as lubricant-infused self-cleaning surfaces.

  1. A Compliant Mechanism Synthesis Theory for Fostering Innovation of Micro Air Vehicles

    DTIC Science & Technology

    2016-04-01

    to note that the HMF and FWMAV are compliant variations of the isomorphic four-bar linkages, as seen in the adjacency matrices. Insect -like kinematics...requires control over three DOF: stroke, pitching, and stroke plane devi- ation. Otherwise, a MAV will approximate insect -like flight through the use...generate insect -like kinematics. Additional control surfaces, auxiliary mechanisms, and actuators will be required to produce a better approximation of

  2. Experimental investigation on materials and lubricants for sliding-vane air compressors

    NASA Astrophysics Data System (ADS)

    Murgia, Stefano; Valenti, Gianluca; Contaldi, Giulio; Valenti, Alessandro

    2015-08-01

    Positive-displacement compressors and, among them, sliding-vane rotary machines are widely used in the compressed air sector. As in many other industrial fields, the efficient utilization of energy has become a major goal also in this sector. The aim of the present activity is the experimental investigation on the influence of two vanes materials (cast iron and aluminium with anodized surface) and of four commercial lubricants (characterized by different formulations and additives concentrations) on the performance of a mid-capacity sliding-vane rotary compressor in a number of operating pressures. The performance is identified by both the volume flow rate and the absorbed mechanical power, evaluated according to the international standard ISO 5167 and ISO 1217. The campaign indicates that the considered lubricants do not affect appreciably the volumetric flow rate. On the other hand, the specific lubricants determine a variation of about 1% of the mechanical power for both materials, while the specific material a variation between 0.9% and 2.6%. The best performance is achieved by aluminium vanes and a synthetic poly-α-olefin lubricant.

  3. Boundary lubrication of formulated C-ethers in air to 300 C. 2: Organic acid additives

    NASA Technical Reports Server (NTRS)

    Jones, W. R., Jr.

    1973-01-01

    Friction and wear measurements were made on CVM M-50 steel lubricated with three C-ether (modified polyphenyl ether) formulations in dry and moist air. Results were compared to those obtained with a formulated Type 2 ester and the C-ether base fluid. A ball-on-disk sliding friction apparatus was used. Experimental conditions were a 1-kilogram load, a 17-meter/minute surface speed, and a 25 to 300 C (77 to 572 F) disk temperature range. The three C-ether formulations yielded better boundary lubricating characteristics than the Type 2 ester under most test conditions. All C-ether formulations exhibited higher friction coefficients than the ester from 150 to 300 C (302 to 572 F) and similar or lower values from 25 to 150 C (77 to 302 F).

  4. Efficient Computation of Separation-Compliant Speed Advisories for Air Traffic Arriving in Terminal Airspace

    NASA Technical Reports Server (NTRS)

    Sadovsky, Alexander V.; Davis, Damek; Isaacson, Douglas R.

    2012-01-01

    A class of problems in air traffic management asks for a scheduling algorithm that supplies the air traffic services authority not only with a schedule of arrivals and departures, but also with speed advisories. Since advisories must be finite, a scheduling algorithm must ultimately produce a finite data set, hence must either start with a purely discrete model or involve a discretization of a continuous one. The former choice, often preferred for intuitive clarity, naturally leads to mixed-integer programs, hindering proofs of correctness and computational cost bounds (crucial for real-time operations). In this paper, a hybrid control system is used to model air traffic scheduling, capturing both the discrete and continuous aspects. This framework is applied to a class of problems, called the Fully Routed Nominal Problem. We prove a number of geometric results on feasible schedules and use these results to formulate an algorithm that attempts to compute a collective speed advisory, effectively finite, and has computational cost polynomial in the number of aircraft. This work is a first step toward optimization and models refined with more realistic detail.

  5. Leaping shampoo glides on a 500-nm-thick lubricating air layer

    NASA Astrophysics Data System (ADS)

    Li, Erqiang; Lee, Sanghyun; Marston, Jeremy; Bonito, Andrea; Thoroddsen, Sigurdur

    2013-11-01

    When a stream of shampoo is fed onto a pool in one's hand, a jet can leap sideways or rebound from the liquid surface in an intriguing phenomenon known as the Kaye effect. Earlier studies have debated whether non-Newtonian effects are the underlying cause of this phenomenon, making the jet glide on top of a shear-thinning liquid layer, or whether an entrained air layer is responsible. Herein we show unambiguously that the jet slides on a lubricating air layer [Lee et al., Phys. Rev. E 87, 061001 (2013)]. We identify this layer by looking through the pool liquid and observing its rupture into fine micro-bubbles. The resulting micro-bubble sizes suggest that the thickness of this air layer is around 500 nm. This thickness estimate is also supported by the tangential deceleration of the jet during the rebounding, with the shear stress within the thin air layer sufficient for the observed deceleration. Particle tracking within the jet shows uniform velocity, with no pronounced shear, which would be required for shear-thinning effects. The role of the surfactant may primarily be to stabilize the air film.

  6. Auto-ignition of lubricating oil working at high pressures in a compressor for an air conditioner.

    PubMed

    Kim, Chul Jin; Choi, Hyo Hyun; Sohn, Chae Hoon

    2011-01-15

    Auto-ignition of lubricating oil working in a compressor for an air conditioner is studied experimentally. The adopted lubricating oil is an unknown mixture with multi-components and known to have flash point temperature of 170 °C. First, its auto-ignition temperature is measured 365 °C at atmospheric pressure. The lubricating oil works under high-pressure condition up to 30 atm and it is heated and cooled down repeatedly. Accordingly, auto-ignition temperatures or flammable limits of lubricating oil are required at high pressures with respect to fire safety. Because there is not a standard test method for the purpose, a new ignition-test method is proposed in this study and thereby, auto-ignition temperatures are measured over the pressure range below 30 atm. The measured temperatures range from 215 °C to 255 °C and they strongly depend on pressure of gas mixture consisting of oil vapor, nitrogen, and oxygen. They are close to flash point temperature and the lubricating oil can be hazardous when it works for high-pressure operating condition and abundant air flows into a compressor.

  7. Compliant walker

    NASA Technical Reports Server (NTRS)

    Kerley, James J. (Inventor); Eklund, Wayne D. (Inventor); Crane, J. Allen (Inventor)

    1992-01-01

    A compliant walker is provided for humans having limited use of their legs and lower back. It includes an upright wheel frame which at least partially surrounds an upright user wearing a partial body harness. It is attached to the frame by means of cable compliant apparatus consisting of sets of cable segments and angle bracket members connected between opposite side members of the frame and adjacent side portions of the harness. Novelty is believed to exist in the combination of a wheeled frame including a side support structure, a body harness, and compliance means connecting the body harness to the side support structure for flexibility holding and supporting a person in a substantially upright position when the user sags in the frame when taking weight off the lower extremities.

  8. Boundary lubrication of formulated C-ethers in air to 300 C

    NASA Technical Reports Server (NTRS)

    Jones, W. R., Jr.

    1975-01-01

    Friction and wear measurements were made in dry and moist air on CVM M-50 steel lubricated with six C-ether formulations containing phosphorus ester and organic acid additives. Results were compared to those obtained with a formulated Type 2 ester and the C-ether base fluid. A ball-on-disk sliding friction apparatus was used. Experimental conditions were a 1-kilogram load, 17 meter-per-minute (100 rpm) surface speed, and a 25 to 300 C disk temperature range. The C-ether base fluid and the C-ether formulations yielded lower wear than the ester under most test conditions. The C-ether formulations exhibited higher friction coefficients than the ester from 150 to 300 C and similar or lower values from 25 to 150 C.

  9. High temperature self-lubricating coatings for air lubricated foil bearings for the automotive gas turbine engine

    NASA Technical Reports Server (NTRS)

    Bhushan, B.

    1980-01-01

    coating combinations were developed for compliant surface bearings and journals to be used in an automotive gas turbine engine. The coatings were able to withstand the sliding start/stops during rotor liftoff and touchdown and occasional short time, high speed rubs under representative loading of the engine. Some dozen coating variations of CdO-graphite, Cr2O3 (by sputtering) and CaF2 (plasma sprayed) were identified. The coatings were optimized and they were examined for stoichiometry, metallurgical condition, and adhesion. Sputtered Cr2O3 was most adherent when optimum parameters were used and it was applied on an annealed (soft) substrate. Metallic binders and interlayers were used to improve the ductility and the adherence.

  10. Compliant joint

    NASA Technical Reports Server (NTRS)

    Eklund, Wayne D. (Inventor); Kerley, James J. (Inventor)

    1990-01-01

    A compliant joint is provided for prosthetic and robotic devices which permits rotation in three different planes. The joint provides for the controlled use of cable under motion. Perpendicular outer mounting frames are joined by swaged cables that interlock at a center block. Ball bearings allow for the free rotation of the second mounting frame relative to the first mounting frame within a predetermined angular rotation that is controlled by two stop devices. The cables allow for compliance at the stops and the cables allow for compliance in six degrees of freedom enabling the duplication or simulation of the rotational movement and flexibility of a natural hip or knee joint, as well as the simulation of a joint designed for a specific robotic component for predetermined design parameters.

  11. Compliant cantilevered micromold

    DOEpatents

    Morales, Alfredo Martin; Domeier, Linda A.; Gonzales, Marcela G.; Keifer, Patrick N.; Garino, Terry Joseph

    2006-08-15

    A compliant cantilevered three-dimensional micromold is provided. The compliant cantilevered micromold is suitable for use in the replication of cantilevered microparts and greatly simplifies the replication of such cantilevered parts. The compliant cantilevered micromold may be used to fabricate microparts using casting or electroforming techniques. When the compliant micromold is used to fabricate electroformed cantilevered parts, the micromold will also comprise an electrically conducting base formed by a porous metal substrate that is embedded within the compliant cantilevered micromold. Methods for fabricating the compliant cantilevered micromold as well as methods of replicating cantilevered microparts using the compliant cantilevered micromold are also provided.

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

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

  13. Start-stop testing of two self-acting air-lubricated spiral groove thrust bearing coatings

    NASA Technical Reports Server (NTRS)

    Dunfee, J. D.; Shapiro, W.

    1974-01-01

    Start-stop tests were conducted on air-lubricated spiral-groove thrust bearings. Application of a matrix-bonded molybdenum disulfide (MoS2) coating over a porous chrome oxide coating resulted in significantly lower friction, compared to bearings coated with chrome oxide only. The MoS2 coated bearing sustained 15,000 start-stop cycles at a maximum of 3600 rpm. Each cycle was 15 seconds on, 30 seconds off. The chrome oxide coated bearing failed by local welding after 2030 cycles. Both types of coatings exhibited early failures under higher thrust loads when operating films were insufficient to sustain the load without overheating.

  14. Multi-elemental analysis of jet engine lubricating oils and hydraulic fluids and their implication in aircraft air quality incidents.

    PubMed

    van Netten, C

    1999-05-07

    The flight crews of aircraft often report symptoms including dizziness, nausea, disorientation, blurred vision and tingling in legs and arms. Many of these incidents have been traced to contamination of cabin air with lubricating oil, as well as hydraulic fluid, constituents. Considering that these air contaminants are often subjected to temperatures in excess of 500 degrees C, a large number of different exposures can be expected. Although the reported symptoms are most consistent with exposures to volatile organic compounds, carbon monoxide, and the organophosphate constituents in these oils and fluids, the involvement of these agents has not been clearly demonstrated. Possible exposure to toxic elements, such as lead, mercury, thallium and others, have not been ruled out. In order to assess the potential of exposure to toxic elements a multi-elemental analysis was done on two hydraulic fluids and three lubricating oils which have been implicated in a number of air quality incidents. A secondary objective was to establish if the multi-elemental concentrations of the fluids tested are different enough to allow such an analysis to be used as a possible method of identifying the source of exposure that might have been present during aircraft air quality incidents. No significant concentrations of toxic elements were identified in any of the oils or hydraulic fluids. The elemental compositions of the samples were different enough to be used for identification purposes and the measurement of only three elements was able to achieve this. Whether these findings have an application, in aircraft air quality incident investigations, needs to be established with further studies.

  15. Tractor-Maintenance: Operation & Daily Care [and] Servicing Air Cleaner & Lubrication. Student Materials. V. A. III. [V-C-1 through V-C-4].

    ERIC Educational Resources Information Center

    Texas A and M Univ., College Station. Vocational Instructional Services.

    Designed for use by students in vocational agricultural classes, this manual deals with tractor maintenance. Operation and daily care are the topics of the first section. Safety is also covered. In the final part of the manual, servicing the air cleaner and lubricating the engine are discussed. Both sections conclude with a quiz. (PLB)

  16. Compliant Baffle for Large Telescope Daylight Imaging

    DTIC Science & Technology

    2014-09-01

    Compliant Baffle for Large Telescope Daylight Imaging Steven Griffin, Andrew Whiting, Shawn Haar The Boeing Company Stacie Williams Air Force...not impact wind loading induced jitter on the 3.6 m telescope . Analysis was performed to design a compliant baffle out of a synthetic fabric that...will be a comparison of angular rate sensors and accelerometers mounted on the telescope . 1.0 INTRODUCTION Unsteady wind loading is the largest

  17. Boundary lubrication of formulated C-ether in air to 300 deg C. 1: Phosphorus ester additives

    NASA Technical Reports Server (NTRS)

    Jones, W. R., Jr.; Hady, W. F.

    1972-01-01

    Friction and wear measurements were made on CVM M-50 steel lubricated with three C-ether (modified polyphenyl ether) formulations in dry and wet air. Results were compared to those obtained with a formulated Type 2 ester and the C-ether base fluid. A ball-on-disk sliding friction apparatus was used. Experimental conditions were a 1-kilogram load, a 17-meter-perminute (100-rpm) surface speed, and a 25 to 300 C (77 to 572 F) disk temperature range. The C-ether base fluid and the three formulated C-ether fluids yielded lower wear than the Type 2 ester over the entire temperature range. All C-ether fluids exhibited slightly higher friction coefficients than the ester from 150 to 300 C (302 to 572 F) and similar values from 25 to 150 C (77 to 302 F). In general, lower wear rates were observed with the C-ethers when tested in wet air as compared to a dry air atmosphere.

  18. SYNTHETIC LUBRICANTS

    DTIC Science & Technology

    of synthetic lubricants for use at low and high temperatures. The diesters of straight-chain dibasic acids lead the field of esters mutable as...lubricants for use at both low and high temperatures, because of their desirable combinations of properties and potentially good availability. Adipic ...azelaic, and sebacic acids are the most readily available dibasic acids suitable for ester lubricant production, while the petroleum derived Oxo alcohols

  19. 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.

  20. 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.

  1. Solid lubricant materials for high temperatures: A review

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1985-01-01

    Solid lubricants that can be used above 300 C in air are discussed, including coatings and self-lubricating composite bearing materials. The lubricants considered are representative dichalcogenides, graphite, graphite fluoride, polyimides, soft oxides, oxidatively stable fluorides, and hard coating materials. A few general design considerations revelant to solid lubrication are interspersed.

  2. Self-lubricating coatings for high-temperature applications

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1990-01-01

    Solid lubricants with maximum temperature capabilities of about 1100 C are known. Unfortunately, none of the solid lubricants with the highest temperature capabilities are effective below 400 C. However, research at NASA's Lewis Research Center shows that silver and stable fluorides such as calcium and barium fluorides act synergistically to provide lubrication from below room temperature to about 900 C. This paper describes plasma-sprayed composite coatings that contain these solid lubricants in combination with a metal-bonded chromium carbide. The lubricants control friction, and the carbide matrix provides wear resistance. Successful tests of these coatings as backup lubricants for compliant gas bearings in turbomachinery and as self-lubricating liners in a four-cylinder Stirling engine are discussed.

  3. Lubricant Evaluation and Performance 2

    DTIC Science & Technology

    1994-02-01

    POWER DIRECTORATE WRIGHT LABORATORY AIR FORCE MATERIEL COMMAND WRIGHT-PATrERSON AIR FORCE BASE , OHIO 45433-7103 94 5 10 011 NOTICE When government...INTRODUCTION I R DEVELOPMENT OF IMPROVED METHODS FOR MEASURING LUBRICANT PERFORMANCE 3 1 OXIDATIVE STABILITY OF ESTER BASE LUBRICANTS 3 a. Introduction 3 b...7) Conclusions 134 i. Stability Testing of Cyclophosphazene Based Fluids 134 (1) Introduction 134 (2) Effect of Metal Specimens 134 (3) Effect of a

  4. 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.

  5. Apparent contact angles induced by evaporation into air: interferometric measurements and lubrication-type modeling

    NASA Astrophysics Data System (ADS)

    Colinet, Pierre; Tsoumpas, Yannis; Dehaeck, Sam; Rednikov, Alexey

    2014-11-01

    For volatile liquids, finite contact angles on solid substrates can occur even in the case of perfect wetting, immobile contact lines and ideally smooth surfaces. This is a fluid-dynamic effect due to evaporation typically intensifying towards a small vicinity of the contact line. In the present talk, we first overview recent theoretical results on the subject, where we focus primarily on the case of diffusion-limited evaporation into air. The model is based upon the so-called de Gennes' paradigm, incorporating simultaneously the spreading coefficient and the disjoining pressure in the form of an inverse cubic law. Then we carry out comparison with experimental results for the contact angles of evaporating sessile drops of several perfectly-wetting HFE liquids of different volatility recently obtained by Mach-Zehnder interferometry. The scaling-type theoretical prediction for the apparent contact angle is found to be in good agreement with experimental measurements. Another model based upon the Kelvin effect (curvature dependence of the saturation conditions) is also briefly discussed, an important conceptual feature of which being that contact-line singularities (both evaporation- and motion-induced) can be fully regularized, in contrast with the first model. Support from ESA, BELSPO and FRS-FNRS is gratefully acknowledged.

  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. Formulation and evaluation of C-Ether fluids as lubricants useful to 260 C. [air breathing engines

    NASA Technical Reports Server (NTRS)

    Clark, F. S.; Miller, D. R.

    1980-01-01

    Three base stocks were evaluated in bench and bearing tests to determine their suitability for use at bulk oil temperatures (BOT) from -40 C to +260 C. A polyol ester gave good bearing tests at a bulk temperature of 218 C, but only a partially successful run at 274 C. These results bracket the fluid's maximum operating temperature between these values. An extensive screening program selected lubrication additives for a C-ether (modified polyphenyl ether) base stock. One formulation lubricated a bearing for 111 hours at 274 C (BOT), but this fluid gave many deposit related problems. Other C-ether blends produced cage wear or fatigue failures. Studies of a third fluid, a C-ether/disiloxane blend, consisted of bench oxidation and lubrication tests. These showed that some additives react differently in the blend than in pure C-ethers.

  8. Smooth Compliant Antifoulant Coatings.

    DTIC Science & Technology

    1982-09-30

    chain. The elastomer approach uses a conventional elastomeric material, such as neoprene, as a basic vehicle. The biocide is then blended with it. The...acoustic properties can be achieved without the structural limitations of elastomeric materials normally classed as compliant. Therefore, compliance, as...conventio paint base, they leach out too quickly to be acceptable for ACSAS. However, chemical incorporation of the biocide within elastomers such as

  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. Static evaluation of surface coatings for compliant gas bearings in an oxidizing atmosphere to 650 C

    NASA Technical Reports Server (NTRS)

    Bhushan, B.; Gray, S.

    1978-01-01

    Hard wear-resistant coatings and soft low shear strength coatings were developed for an air-lubricated compliant journal bearing for a future automotive gas turbine engine. The coatings were expected to function in either 540 or 650 C ambient. Soft lubricant coatings were generally limited in temperature. Therefore emphasis was on the hard wear-resistant coatings. The coating materials covered were TiC, B4C, Cr3C2, WC, SiC, CrB2, TiB2, Cr2O3, Al2O3, Si3N4, Tribaloy 800, CaF2, CaF2-BaF2 eutectic, Ni-Co, silver, CdO-graphite and proprietary compounds. The coatings on test coupons were subjected to static oven screening tests. The test consisted of exposure of material samples in an oven for 300 h at the maximum temperature (540 or 650 C) and ten temperature cycles from room temperature to the maximum service temperature. On the basis of the specimen examinations the following coatings were recommended for future wear tests: TiC (sputtered), Cr2O3 (sputtered), Si3N4 (sputtered), CdO and graphite (fused), Kaman DES (a proprietary coating), CrB2 (plasma sprayed), Cr3C2 (detonation gun) and NASA PS-106 (plasma sprayed).

  11. Lubricating compositions

    SciTech Connect

    Harrison, J.J.; Campbell, C.B.

    1993-08-03

    A lubricating composition is described comprising a major amount of oil of lubricating viscosity and a minor amount of an oil-soluble composition selected from the group consisting of: (A) an alkali metal salt of a polyalkenyl succinimide which is the reaction product of (a) a polyalkenyl succinic acid or polyalkenyl succinic anhydride, with (b) an amine selected from the group consisting of polyamines and hydroxy-substituted polyamines; and (B) a mixture comprising: (1) an oil-soluble alkali metal compound; and (2) a polyalkenyl succinimide which is the reaction product of (a) a polyalkenyl succinic acid or polyalkenyl succinic anhydride, with (b) an amine selected from the group consisting of polyamines and hydroxy-substituted polyamines; wherein the polyalkenyl succinic acid and polyalkenyl succinic anhydride are prepared by a thermal reaction, and the lubricating composition has a sufficient amount of basic nitrogen content so that the use of from 7.91 to about 50 mmoles of alkali metal/kg lubricant composition provides for reductions in the lower piston deposits as compared to the lubricant composition not containing alkali.

  12. Compliant Joints For Robots

    NASA Technical Reports Server (NTRS)

    Kerley, James J., Jr.

    1990-01-01

    Compliant joints devised to accommodate misalignments of tools and/or workpieces with respect to robotic manipulators. Has characteristics and appearance of both universal-joint and cable-spring-type flexible shaft coupling. Compliance derived from elastic properties of short pieces of cable. Compliance of joint determined by lengths, distances between, relative orientations, thickness of strands, number of strands, material, amount of pretwist, and number of short pieces of cable. Worm-drive mechanism used to adjust lengths to vary compliance as needed during operation.

  13. Lubricant compositions

    SciTech Connect

    Johnson, A.L.; Lawson, R.D.; Root, J.C.

    1981-12-15

    Lubricant compositions adapted for use under extreme pressure conditions are disclosed. They comprise a major proportion of a lubricating grease, and a minor proportion of an additive consisting essentially of a solid, oil insoluble arylene sulfide polymer, and a metal salt, particularly an alkali metal or alkaline earth metal salt, particularly an alkali metal or alkaline earth metal salt of a phosphorus acid, for example, mono- or dicalcium phosphate, or an alkali metal or alkaline earth metal carbonate exemplified by calcium carbonate, or a mixture of such a phosphate salt and carbonate.

  14. 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.

  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. 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.

  17. Preliminary Investigation of Molybdenum Disulfide-air-mist Lubrication for Roller Bearings Operating to DN Values of 1 x 10(exp 6) and Ball Bearings Operating to Temperatures of 1000 F

    NASA Technical Reports Server (NTRS)

    Macks, E F; Nemeth, Z N; Anderson, W J

    1951-01-01

    The effectiveness of molybdenum disulfide MoS2 as a bearing lubricant was determined at high temperature and at high speeds. A 1-inch-bore ball bearing operated at temperatures to 1000 F, a speed of 1725 rpm, and a thrust load of 20 pounds when lubricated only with MoS2-air mist. A 75-millimeter-bore cageless roller bearing, provided with a MoS2-syrup coating before operation, operated at DN values to 1 x 10(exp 6) with a load of 368 pounds.

  18. Compliant Turbomachine Sealing

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Braun, M. J.; Deng, D.; Hendricks, J. A.

    2011-01-01

    Sealing interface materials and coatings are sacrificial, giving up their integrity for the benefit of the component. Seals that are compliant while still controlling leakage, dynamics, and coolant flows are sought to enhance turbomachine performance. Herein we investigate the leaf-seal configuration. While the leaf seal is classified as contacting, a ready modification using the leaf-housing arrangement in conjunction with an interface film rider (a bore seal, for example) provides for a film-riding noncontact seal. The leaf housing and leaf elements can be made from a variety of materials from plastic to ceramic. Four simplistic models are used to identify the physics essential to controlling leakage. Corroborated by CFD, these results provide design parameters for applications to within reasonable engineering certainty. Some potential improvements are proposed.

  19. Compliant seal development

    NASA Technical Reports Server (NTRS)

    Hendricks, Robert C.

    1993-01-01

    The compliant metallic seal combines the noncontact feature of the labyrinth seal, the low leakage of a mechanical seal, and the compliant nature of the brush seal. It consists of several thin metallic elements or leaves mounted within a ring which is press fit into the housing, and in form, sort of resembles a lip seal sections wiping the shaft. A second set of overlapping cover leaves are placed on top of the shaft riding leaves which reduces leakage and provides stiffness. The leaves can be straight or angle cut. The shaft riding fingers are designed with mismatched curvature to provide lift off similar to the Rayleigh lift pads in mechanical seals with leading edge clearances nearly twice those of the trailing edge as as shown by Fleming to be optimal for gas flows in convergent seal passages. Leading edge clearances range from 300 to 500 microinches. Balance pockets beneath the leaves provide fluid film feed to the 'Rayleigh lift' surface and the proper balance ratio (mechanical seal) when combined with the static pressure and film pressure. The leaves flex in the radial direction and accommodate thermomechanical behavior as well as axial motion and angular misalignment. In the static mode, there is a net closing force on the leaves. The seals were tested to 70 psi at speeds to 16,000 rpm or surface speeds to 330 fps and temperatures from ambient to 440 F. A slow cycle through the rig critical at 10,000 rpm induced a radial vibration response of 0.004 to 0.005 inch were accommodated by the seal. Preliminary performance data are encouraging demonstrating hydrodynamic liftoff and noncontacting operation at pressure and speeds typical of gas turbine engines. The leakage performance data are significantly better than commercial labyrinth and brush seals which should be expected as this design incorporates the features of the low leakage face or mechanical seal along with the flexibility of the brush configuration.

  20. Environmentally Compliant Coating Remover Evaluation

    DTIC Science & Technology

    2012-08-30

    Penetrating Lubricants 16 10 Metalworking Fluids 62 8 Sorbents 72 17 Adhesive and Mastic Removers 25 19 Greases 18 5 Glass Cleaners 11 11 Firearm...Lubricants 8 2 Chain, Cable, and Gear Lubricants 33 13 Corrosion Preventatives 19 10 Industrial and Multipurpose Cleaners 114 40 Parts Wash Solutions...AND ADDRESS(ES) 10 . SPONSOR/MONITOR’S ACRONYM(S) 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for

  1. 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.

  2. Liquid lubrication for space applications

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.; Khonsari, Michael M.

    1993-01-01

    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.

  3. 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.

  4. 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

  5. Rheology in lubrication

    NASA Technical Reports Server (NTRS)

    Cheng, H. S.

    1973-01-01

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

  6. Compliant Synergies in Locomotion

    NASA Astrophysics Data System (ADS)

    Travers, Matthew; Choset, Howie; Goldman @ Georgia Tech. Physics Department Collaboration

    Biological systems appear to have natural mechanisms that allow them to readily compensate for unexpected environmental variations when compared to their mechanical (i.e., robotic) counterparts. We hypothesize that the basis for this discrepancy is almost innate: what biology appears to be born with, built-in mechanisms for coordinating their many degrees of freedom, we struggle to ``program.'' We therefore look toward biology for inspiration. In particular, we are interested in kinematic synergies, low-dimensional representations that explicitly encode the underlying structure of how systems coordinate their internal degrees of freedom to achieve high-level tasks. In this work, we derive parametric representations of kinematic synergies and present a new compliant locomotion control framework that enables the parameters to be directly controlled in response to external disturbances. We present results of this framework implemented on two separate platforms, a snake-like and hexapod robot. Our results show that, using synergies, the locomotion control of these very different systems can be reduced to simple, extremely capable, and common forms, thus offering new insights into both robotic as well as biological locomotion in complex terrains.

  7. Microfog lubrication for aircraft engine bearings

    NASA Technical Reports Server (NTRS)

    Rosenlieb, J. W.

    1976-01-01

    An analysis and system study was performed to provide design information regarding lubricant and coolant flow rates and flow paths for effective utilization of the lubricant and coolant in a once through bearing oil mist (microfog) and coolant air system. Both static and dynamic tests were performed. Static tests were executed to evaluate and calibrate the mist supply system. A total of thirteen dynamic step speed bearing tests were performed using four different lubricants and several different mist and air supply configurations. The most effective configuration consisted of supplying the mist and the major portion of the cooling air axially through the bearing. The results of these tests have shown the feasibility of using a once through oil mist and cooling air system to lubricate and cool a high speed, high temperature aircraft engine mainshaft bearing.

  8. Method for providing a compliant cantilevered micromold

    DOEpatents

    Morales, Alfredo M.; Domeier, Linda A.; Gonzales, Marcela G.; Keifer, Patrick N.; Garino, Terry J.

    2008-12-16

    A compliant cantilevered three-dimensional micromold is provided. The compliant cantilevered micromold is suitable for use in the replication of cantilevered microparts and greatly simplifies the replication of such cantilevered parts. The compliant cantilevered micromold may be used to fabricate microparts using casting or electroforming techniques. When the compliant micromold is used to fabricate electroformed cantilevered parts, the micromold will also comprise an electrically conducting base formed by a porous metal substrate that is embedded within the compliant cantilevered micromold. Methods for fabricating the compliant cantilevered micromold as well as methods of replicating cantilevered microparts using the compliant cantilevered micromold are also provided.

  9. Lubricant composition

    SciTech Connect

    Baile, G.H.

    1980-12-16

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

  10. 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.

  11. An experimental and theoretical study of structural damping in compliant foil bearings

    NASA Technical Reports Server (NTRS)

    Ku, C.-P. Roger

    1994-01-01

    This paper describes an experimental investigation into the dynamic characteristics of corrugated foil (bump foil) strips used in compliant surface foil bearings. This study provided and opportunity to quantify the structural damping of bump foil strips. The experimental data were compared to results obtained by a theoretical model developed earlier. The effects of bearing design parameters, such as static loads, dynamic displacement amplitudes, bump configurations, pivot locations, surface coatings, and lubricant were also evaluated. An understanding of the dynamic characteristics of bump foil strips resulting from this work offers designers a means for enhancing the design of high-performance compliant foil bearings.

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

    SciTech Connect

    Cavestri, R.C.

    1997-07-01

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

  13. Lubrication Of Nonconformal Contacts

    NASA Technical Reports Server (NTRS)

    Jeng, Yeau-Ren

    1991-01-01

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

  14. Mechanism of lubrication by tricresylphosphate (TCP)

    NASA Technical Reports Server (NTRS)

    Faut, O. D.; Wheeler, D. R.

    1983-01-01

    A pin-on-disk tribometer equipped with an induction heater was used to study the coefficient of friction as a function of temperature for tricresylphosphate (TCP) on continuous vacuum melted (CVM) M-50 tool steel when the TCP was present in a liquid reservoir (bulk lubrication), and when it was applied as a liquid layer directly to the disk (limited lubrication). Under limited lubrication conditions, experiments were performed in dry ( 100 ppm H2O) air, dry ( 20 ppm H2O) nitrogen, dry nitrogen with the disks heated to 700 C then cooled to room temperature before the TCP was applied and the measurements made (preheated disks), and moist nitrogen using preheated disks. When the coefficient of friction was plotted as a function of the disk temperature, the friction decreased at a characteristic temperature, T sub r whose observed values were 265 C for bulk lubrication conditions in dry air, 225 C for limited lubrication conditions in dry air, and 215 C for limited lubrication conditions in dry nitrogen. No decrease in friction was observed with preheated disks; instead a sharp failure temperature was observed at 218 C, which was taken as the temperature about which the behavior of TCP should be judged, X-ray photoelectron spectroscopy confirmed the presence of phosphate on the surface of the iron pins used in the tribometer under TCP lubrication. Depth profile studies support the idea that a chemical reaction occurs between the TCP and the metal surface at T sub r.

  15. Lubricant Evaluation and Performance

    DTIC Science & Technology

    1989-04-01

    Changes on COBRA Response 313 c. Nature of Charge Carrier in COBRA Active Lubricants 313 (I) Adsorption Chromatography of Degraded Lubricants 316 (2...Lubricant 0-67-1 160 (5) Summary 162 b. Micro Carbon Residue Tester (MCRT) 163 (1) Introduction 163 (2) Test Apparatus and Procedure 164 (3) Test...Other COBRA Active Compounds 326 d. Conclusions 329 4. DIELECTRIC BREAKDOWN STRENGTH OF MIL-L-7808 LUBRICANTS 330 V LUBRICANT LOAD CARRYING

  16. 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.

  17. Load-Induced Hydrodynamic Lubrication of Porous Films.

    PubMed

    Khosla, Tushar; Cremaldi, Joseph; Erickson, Jeffrey S; Pesika, Noshir S

    2015-08-19

    We present an exploratory study of the tribological properties and mechanisms of porous polymer surfaces under applied loads in aqueous media. We show how it is possible to change the lubrication regime from boundary lubrication to hydrodynamic lubrication even at relatively low shearing velocities by the addition of vertical pores to a compliant polymer. It is hypothesized that the compressed, pressurized liquid in the pores produces a repulsive hydrodynamic force as it extrudes from the pores. The presence of the fluid between two shearing surfaces results in low coefficients of friction (μ ≈ 0.31). The coefficient of friction is reduced further by using a boundary lubricant. The tribological properties are studied for a range of applied loads and shear velocities to demonstrate the potential applications of such materials in total joint replacement devices.

  18. Lubrication in tablet formulations.

    PubMed

    Wang, Jennifer; Wen, Hong; Desai, Divyakant

    2010-05-01

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

  19. Compliant transducer measures artery profile

    NASA Technical Reports Server (NTRS)

    Feldstein, C.; Culler, V. H.; Crawford, D. W.; Spears, J. R.

    1981-01-01

    Instrument consisting of compliant fingers with attached semiconductor pickups measures inside contours of narrow vessels. Instrument, originally designed to monitor human arteries, is drawn through vessel to allow finges to follow contours. Lead wires transmit electrical signals to external processing equipment.

  20. 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.

  1. Environmentally Acceptable Lubricants

    DTIC Science & Technology

    2011-11-30

    referred to as environmentally friendly lubricants ( EFLs ) or biolubricants. EPA, wastewater, lubricants, oil, biolubricants, VGP, vessels U U U UU 27...qualities, but have not been demonstrated to meet these standards, are referred to as environmentally friendly lubricants ( EFLs ) or biolubricants...clarify the difference between EAL and EFL products in the marketplace. Because the majority of a lubricant is composed of the base oil, the base oil

  2. Mechanics of a gaseous film barrier to lubricant wetting of elastohydrodynamically lubricated conjunctions

    NASA Technical Reports Server (NTRS)

    Prahl, J. M.; Hamrock, B. J.

    1985-01-01

    Two analytical models, one based on simple hydrodynamic lubrication and the other on soft elastohydrodynamic lubrication, are presented and compared to delineate the dominant physical parameters that govern the mechanics of a gaseous film between a small droplet of lubricant and the outer race of a ball bearing. Both models are based on the balance of gravity forces, air drag forces, and air film lubrication forces and incorporate a drag coefficient C sub D and a lubrication coefficient C sub L to be determined from experiment. The soft elastohydrodynamic lubrication (EHL) model considers the effects of droplet deformation and solid-surface geometry; the simpler hydrodynamic lubrication (HL) model assumes that the droplet remains essentially spherical. The droplet's angular position depended primarily on the ratio of gas inertia to droplet gravity forces and on the gas Reynolds number and weakly on the ratio of droplet gravity forces to surface tension forces (Bond number) and geometric ratios for the soft EHL. An experimental configuration in which an oil droplet is supported by an air film on the rotating outer race of a ball bearing within a pressure-controlled chamber produced measurements of droplet angular position as a function of outer-race velocity droplet size and type, and chamber pressure.

  3. 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.

  4. Lubrication forces in air and accommodation coefficient measured by a thermal damping method using an atomic force microscope

    NASA Astrophysics Data System (ADS)

    Honig, Christopher D. F.; Sader, John E.; Mulvaney, Paul; Ducker, William A.

    2010-05-01

    By analysis of the thermally driven oscillation of an atomic force microscope (AFM) cantilever, we have measured both the damping and static forces acting on a sphere near a flat plate immersed in gas. By varying the proximity of the sphere to the plate, we can continuously vary the Knudsen number (Kn) at constant pressure, thereby accessing the slip flow, transition, and molecular regimes at a single pressure. We use measurements in the slip-flow regime to determine the combined slip length (on both sphere and plate) and the tangential momentum accommodation coefficient, σ . For ambient air at 1 atm between two methylated glass solids, the inverse damping is linear with separation and the combined slip length on both surfaces is 250nm±100nm , which corresponds to σ=0.77±0.24 . At small separations (Kn>0.4) the measured inverse damping is no longer linear with separation, and is observed to exhibit reasonable agreement with the Vinogradova formula.

  5. Collision forces for compliant projectiles

    NASA Technical Reports Server (NTRS)

    Grady, Joseph E.

    1990-01-01

    Force histories resulting from the impact of compliant projectiles were determined experimentally. A long instrumented rod was used as the target, and the impact force was calculated directly from the measured strain response. Results from a series of tests on several different sized impactors were used to define four dimensionless parameters that determine, for a specified impactor velocity and size, the amplitude, duration, shape, and impulse of the impact force history.

  6. Compatibility of refrigerants and lubricants with elastomers

    SciTech Connect

    Hamed, G.R.; Seiple, R.H.

    1992-07-01

    Information contained in this reporters designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. Swell measurements have been made on approximately 50% of the proposed elastomers (94 total)in both the lubricant (7 total) and refrigerant (10 total) materials. Swell behavior in the these fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 hours and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

  7. Design of Surface micromachined Compliant MEMS

    SciTech Connect

    Bradley, Joe Anthony

    2001-01-01

    The consideration of compliant mechanisms as Microelectromechanical Systems (MEMS) is the focus of this research endeavor. MEMS are micron to millimeter devices that combine electrical, mechanical, and information processing capabilities on the same device. These MEMS need some mechanical motion or parts that move relative to each other. This relative motion, using multiple parts, is not desired because of the assembly requirement and the friction introduced. Compliant devices limits or eliminates friction and the need for multi-component assembly. Compliant devices improve designs by creating single piece mechanisms. The purpose of this research is to validate surface micromachining as a viable fabrication process for compliant MEMS designs. Specifically, this research has sought to fabricate a micro-compliant gripper and a micro-compliant clamp to illustrate the process. While other researchers have created compliant MEMS, most have used comb-drive actuation methods and bulk micromachining processes. This research focuses on fully-compliant devices that use device flexibility for motion and actuation. Validation of these compliant MEMS is achieved by structural optimization of device design and functional performance testing. This research contributes to the ongoing research in MEMS by evaluating the potential of using surface micromachining as a process for fabricating compliant micro-mechanisms.

  8. Design of Surface Micromachined Compliant MEMS

    SciTech Connect

    Bradley, Joe Anthony

    2002-12-31

    The consideration of compliant mechanisms as Microelectromechanical Systems (MEMS) is the focus of this research endeavor. MEMS are micron to millimeter devices that combine electrical, mechanical, and information processing capabilities on the same device. These MEMS need some mechanical motion or parts that move relative to each other. This relative motion, using multiple parts, is not desired because of the assembly requirement and the friction introduced. Compliant devices limits or eliminates friction and the need for multi-component assembly. Compliant devices improve designs by creating single piece mechanisms. The purpose of this research is to validate surface micromachining as a viable fabrication process for compliant MEMS designs. Specifically, this research has sought to fabricate a micro-compliant gripper and a micro-compliant clamp to illustrate the process. While other researchers have created compliant MEMs, most have used comb-drive actuation methods and bulk micromachining processes. This research focused on fully-compliant devices that use device flexibility for motion and actuation. Validation of these compliant MEMS is achieved by structural optimization of device design and functional performance testing. This research contributes to the ongoing research in MEMS by evaluating the potential of using surface micromachining as a process for fabricating compliant micro-mechanisms.

  9. 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.

  10. Compliant Prosthetic Or Robotic Joint

    NASA Technical Reports Server (NTRS)

    Kerley, James J.; Eklund, Wayne D.

    1989-01-01

    Rotation partly free and partly restrained by resilience and damping. Joint includes U-shaped x- and y-axis frames joined by cables that cross in at center piece. The y-axis frame rotates about y-axis on roller bearing within predetermined angular range. The y-axis frame rotates slightly farther when arm strikes stop, because cables can twist. This mimics compliant resistance of knee joint reaching limit of its forward or backward motion. Used in prosthetic device to replace diseased or damage human joint, or in robot linkage to limit movement and cushion overloads.

  11. Robot cable-compliant devices

    NASA Technical Reports Server (NTRS)

    Kerley, James J., Jr. (Inventor)

    1990-01-01

    A cable compliant robotic joint includes two U configuration cross section brackets with their U cross sections lying in different planes, one of their brackets being connected to a robot arm and the other to a tool. Additional angle brackets are displaced from the other brackets at corners of the robotic joint. All the brackets are connected by cable segments which lie in one or more planes which are perpendicular to the direction of tool travel as it approaches a work object. The compliance of the joint is determined by the cable segment characteristics, such as their length, material, angle, stranding, pretwisting, and prestressing.

  12. 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.

  13. 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.

  14. Foaming characteristics of refigerant/lubricant mixtures

    SciTech Connect

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

    1997-04-01

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

  15. 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.

  16. 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.

  17. 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.

  18. Assessment of Introital Lubrication.

    PubMed

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

    2015-08-01

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

  19. Worldwide lubricant trends

    SciTech Connect

    Not Available

    1986-01-01

    This book presents the papers given at a conference on lubricating oils for internal combustion engines. Topics considered at the conference included worldwide environmental regulations and their impact on lubricant additives, passenger car gasoline engine oils in Japan, valve train wear, the field performance of super premium engine oils, wear resistance, deposits, scale control, oil thickening, low-phosphorus engine oils, bore polishing, the Tornado test, the coordination of international needs for lubricant quality,and the corrosive wear of cast iron under reciprocating lubrication.

  20. Advanced lubrication systems and materials. Final report

    SciTech Connect

    Hsu, S.

    1998-05-07

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

  1. Industry Needs Fulfilled by Patented NASA PS300 Solid Lubricant Technology

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher

    2003-01-01

    In 1999, the NASA Glenn Research Center was awarded a patent (#5866518) for a new high-temperature solid lubricant coating material, PS300. A combination of wear-resistant metals and ceramics with solid lubricant additives, PS300 reduces friction and wear in sliding contacts from below ambient to over 650 C. This lubricant is an outgrowth of over three decades of high-temperature tribological research and was specifically developed as a shaft lubricant to protect foil air bearings used in Oil-Free turbomachinery, like gas turbines. Foil bearings are lubricated by air at high speeds but experience sliding and wear during initial startup and shut down when a lubricating film of air has not yet developed. PS300 shaft coatings have successfully lubricated foil bearings for over 100 000 cycles without wearing out.

  2. Analytical and numerical investigation of structural response of compliant wall materials

    NASA Technical Reports Server (NTRS)

    Goglia, G. L.; Balasubramanian, R.

    1977-01-01

    Surface motion of compliant walls in drag reduction experiments was analyzed. The spectrum of surface motion indicates that membranes over deep cavities respond at low frequencies and large wavelengths. The membrane over a deep cavity is therefore found not to yield the desired reponse predicted by the postulated mechanism. The membrane over a thin air gap is found to act as a wavelength chopper, and analysis of the nonlinear response of the compliant surface indicates its possible suitability for compliant wall experiments. Periodic structures are found to lock in the desired wavelengths of motion. Laminated structures are found to be very ineffective as compliant models, except when there is no bonding between the membrane and the backing. Computer programs developed for these analyses are documented.

  3. Analytical and numerical investigation of structural response of compliant wall materials, part 1

    NASA Technical Reports Server (NTRS)

    Balasubramanian, R.

    1978-01-01

    Surface motion of compliant walls in drag reduction experiments was analyzed. Critical comparison was made between the dynamic motion of the structure and the postulated mechanism of drag reduction. The spectrum of surface motion indicated that membranes over deep cavities respond at low frequencies and large wavelengths. The membrane over a deep cavity is therefore found not to yield the desired response predicted by the postulated mechanism. The membrane over a thin air gap is found to act as a wavelength chopper, and analysis of the nonlinear response of that compliant surface indicated its possible suitability for compliant wall experiments. Periodic structures are found to lock in the desired wavelengths of motion, and it was shown that at least in Kramer's initial experiments they produced high frequency surface motions. Laminated structures are found to be very ineffective as compliant models, except when there is no bonding between the membrane and the backing. Computer programs developed for these analyses are documented.

  4. 40 CFR 1065.740 - Lubricants.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Lubricants. 1065.740 Section 1065.740 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Engine Fluids, Test Fuels, Analytical Gases and Other Calibration Standards § 1065.740...

  5. 40 CFR 1065.740 - Lubricants.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Lubricants. 1065.740 Section 1065.740 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Engine Fluids, Test Fuels, Analytical Gases and Other Calibration Standards § 1065.740...

  6. 40 CFR 1065.740 - Lubricants.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Lubricants. 1065.740 Section 1065.740 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Engine Fluids, Test Fuels, Analytical Gases and Other Calibration Standards § 1065.740...

  7. 40 CFR 1065.740 - Lubricants.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Lubricants. 1065.740 Section 1065.740 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Engine Fluids, Test Fuels, Analytical Gases and Other Calibration Standards § 1065.740...

  8. 40 CFR 1065.740 - Lubricants.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Lubricants. 1065.740 Section 1065.740 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Engine Fluids, Test Fuels, Analytical Gases and Other Calibration Standards § 1065.740...

  9. 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…

  10. 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.

  11. High temperature lubricating process

    DOEpatents

    Taylor, Robert W.; Shell, Thomas E.

    1982-01-01

    It has been difficult to provide adaquate lubrication for load bearing, engine components when such engines are operating in excess of about 475.degree. C. The present invention is a process for providing a solid lubricant on a load bearing, solid surface (14), such as in an engine (10) being operated at temperatures in excess of about 475.degree. C. The process comprises contacting and maintaining steps. A gas phase (42) 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. The solid lubricant is formed directly on the load bearing surface. The method is particularly suitable for use with ceramic engines.

  12. 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.

  13. 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.

  14. 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.

  15. Extremely compliant and highly stretchable patterned graphene

    SciTech Connect

    Zhu, Shuze; Huang, Yinjun; Li, Teng

    2014-04-28

    Graphene is intrinsically ultra-stiff in its plane. Its huge mechanical mismatch when interfacing with ultra-compliant biological tissues and elastomers (7–9 orders of magnitude difference in stiffness) poses significant challenge in its application to functional devices such as epidermal electronics and sensing prosthesis. We offer a feasible and promising solution to this significant challenge by suitably patterning graphene into a nanomesh. Through systematic coarse-grained simulations, we show that graphene nanomesh can be made extremely compliant with nearly zero stiffness up to about 20% elongation and then remain highly compliant up to about 50% elongation.

  16. Compatibility of refrigerants and lubricants with elastomers

    SciTech Connect

    Hamed, G.R.; Seiple, R.H.

    1992-10-01

    Information contained in this report is designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. 97% of the swell measurements have been made to date. The other 3% of the measurements are contingent on the availability of additional quantities of R-32. Swell behavior in the fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 hours and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

  17. Compatibility of refrigerants and lubricants with elastomers

    SciTech Connect

    Hamed, G.R.; Seiple, R.H.

    1993-01-01

    The information contained in this report is designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. 97% of the swell measurements have been made to date. The other 3% of the measurements are contingent on availability of additional R-32. Swell behavior in the fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

  18. A self-lubricating bearing

    NASA Technical Reports Server (NTRS)

    Whitaker, A. F. (Inventor)

    1974-01-01

    An improved bearing structure is described which includes a permanently magnetized porous body filled with an interstitial magnetic lubricant for extending the operational life of self-lubricating bearings. The bearing structure is characterized by a permanently magnetized retainer formed of a porous material and filled with an interstitial magnetic lubricant, whereby the pores serve as lubricant reservoirs from which the lubricant continuously is delivered to a film disposed between contiguous bearing surfaces.

  19. 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.

  20. Solid Lubrication Fundamentals and Applications. Chapter 6

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2000-01-01

    This chapter focuses attention on the friction and wear properties of selected solid lubricating films to aid users in choosing the best lubricant, deposition conditions, and operational variables. For simplicity, discussion of the tribological properties of concern is separated into two parts. The first part of the chapter discusses the different solid lubricating films selected for study including commercially developed solid film lubricants: (1) bonded molybdenum disulfide (MoS2), (2) magnetron-sputtered MoS2, (3) ion-plated silver, (4) ion-plated lead, (5) magnetron-sputtered diamondlike carbon (MS DLC), and (6) plasma-assisted, chemical-vapor-deposited diamondlike carbon (PACVD DEC) films. Marked differences in the friction and wear properties of the different films resulted from the different environmental conditions (ultrahigh vacuum, humid air, and dry nitrogen) and the solid film lubricant materials. The second part of the chapter discusses the physical and chemical characteristics, friction behavior, and endurance life of the magnetron-sputtered MoS2 films. The role of interface species and the effects of applied load, film thickness, oxygen pressure, environment, and temperature on the friction and wear properties are considered.

  1. 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.

  2. Lubrication of Articular Cartilage.

    PubMed

    Jahn, Sabrina; Seror, Jasmine; Klein, Jacob

    2016-07-11

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

  3. Origins of hydration lubrication.

    PubMed

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

    2015-01-14

    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.

  4. 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.

  5. 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.

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

    PubMed

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

    2015-10-14

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

  7. 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.

  8. 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.

  9. Synthesis of new high performance lubricants and solid lubricants

    SciTech Connect

    Lagow, R.J.

    1993-04-01

    Synthesis and testing was begun on a number of new classes of lubricants: perfluoropolyethers (branching effects), perfluoromethylene oxide ethers, chlorine-substituted fluorocarbon polyethers, fluorine-containing branched ether lubricants, glycerine- based perfluoropolyesters, perfluoro epoxy ether chains, etc.

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

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Morales, Wilfredo

    2000-01-01

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

  11. 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.

  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. 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.

  14. Approach for Structurally Clearing an Adaptive Compliant Trailing Edge Flap for Flight

    NASA Technical Reports Server (NTRS)

    Miller, Eric J.; Lokos, William A.; Cruz, Josue; Crampton, Glen; Stephens, Craig A.; Kota, Sridhar; Ervin, Gregory; Flick, Pete

    2015-01-01

    The Adaptive Compliant Trailing Edge (ACTE) flap was flown on the NASA Gulfstream GIII test bed at the NASA Armstrong Flight Research Center. This smoothly curving flap replaced the existing Fowler flaps creating a seamless control surface. This compliant structure, developed by FlexSys Inc. in partnership with Air Force Research Laboratory, supported NASA objectives for airframe structural noise reduction, aerodynamic efficiency, and wing weight reduction through gust load alleviation. A thorough structures airworthiness approach was developed to move this project safely to flight.

  15. Emergency and microfog lubrication and cooling of bearings for Army helicopters

    NASA Technical Reports Server (NTRS)

    Rosenlieb, J. W.

    1978-01-01

    An analysis and system study was performed to provide design information regarding lubricant and coolant flow rates and flow paths for effective utilization of the lubricant and coolant in a once-through oil-mist (microfog) and coolant air system. A system was designed, manufactured, coupled with an existing rig and evaluation tests were performed using 46 mm bore split-inner angular-contact ball bearings under 1779N (400 lb.) thrust load. An emergency lubrication aspirator system was also manufactured and tested under lost lubricant conditions. The testing demonstrated the feasibility of using a mist oil and cooling air system to lubricate and cool a high speed helicopter engine mainshaft bearing. The testing also demonstrated the feasibility of using an emergency aspirator lubrication system as a viable survivability concept for helicopter mainshaft engine bearing for periods as long as 30 minutes.

  16. 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.

  17. 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.

  18. 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.

  19. Additional aspects of elastohydrodynamic lubrication

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.

    1978-01-01

    An up-to-date review of the varying aspects of elastohydrodynamic lubrication is presented.. Some recent work on elastohydrodynamic lubrication of materials of low elastic modulus as well as on hydrodynamic lubrication is included. Both these topics are applicable for contacts with any ellipticity parameter (ranging from a circular contact to a line contact).

  20. 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.

  1. 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.

  2. Fuel-efficient lubricating oil

    SciTech Connect

    Erdman, T.R.

    1986-04-22

    A method is described of improving the fuel economy of an internal combustion engine comprising lubricating the crankcase of the engine with a lubricating composition consisting of a hydrocarbon oil of lubricating viscosity and from 15 to 25 millimols per kilogram of zinc O,O-di(2-ethylhexyl)phosphorodithioate and from 0.25 to 2 weight percent of pentaerythritol monooleate.

  3. Turbine airfoil with a compliant outer wall

    DOEpatents

    Campbell, Christian X [Oviedo, FL; Morrison, Jay A [Oviedo, FL

    2012-04-03

    A turbine airfoil usable in a turbine engine with a cooling system and a compliant dual wall configuration configured to enable thermal expansion between inner and outer layers while eliminating stress formation in the outer layer is disclosed. The compliant dual wall configuration may be formed a dual wall formed from inner and outer layers separated by a support structure. The outer layer may be a compliant layer configured such that the outer layer may thermally expand and thereby reduce the stress within the outer layer. The outer layer may be formed from a nonplanar surface configured to thermally expand. In another embodiment, the outer layer may be planar and include a plurality of slots enabling unrestricted thermal expansion in a direction aligned with the outer layer.

  4. 40 CFR 1065.122 - Engine cooling and lubrication.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ....122 Section 1065.122 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.122 Engine cooling and lubrication. (a) Engine cooling. Cool the engine during testing so its intake-air, oil, coolant, block,...

  5. 40 CFR 1065.122 - Engine cooling and lubrication.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ....122 Section 1065.122 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.122 Engine cooling and lubrication. (a) Engine cooling. Cool the engine during testing so its intake-air, oil, coolant, block,...

  6. 40 CFR 1065.122 - Engine cooling and lubrication.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ....122 Section 1065.122 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.122 Engine cooling and lubrication. (a) Engine cooling. Cool the engine during testing so its intake-air, oil, coolant, block,...

  7. 40 CFR 1065.122 - Engine cooling and lubrication.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ....122 Section 1065.122 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.122 Engine cooling and lubrication. (a) Engine cooling. Cool the engine during testing so its intake-air, oil, coolant, block,...

  8. 40 CFR 1065.122 - Engine cooling and lubrication.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....122 Section 1065.122 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.122 Engine cooling and lubrication. (a) Engine cooling. Cool the engine during testing so its intake-air, oil, coolant, block,...

  9. Railway diesel crankcase lubricant

    SciTech Connect

    Sung, R.L.; Zoleski, B.H.; O'Rourke, R.L.

    1987-06-30

    A railway diesel crankcase lubricant composition is described comprising a diesel lubricating oil and from about 0.25 to 2.0 weight percent of minor amount of oxidation and corrosion inhibiting agent. The reaction product is of a polyoxyisopropylene diamine, diabasic acid anhydride and polyalkylene polyamine wherein: (i) reacting a dibasic acid anhydride with a polyoxyisopropylenediamine where x is a numeral of about 2 to about 50, forming a maleamic acid; (ii) reacting the maleamic acid with a polyalkylene polyamine, forming a condensate product and; (iii) recovering the condensate product.

  10. Lubricants in conveyor applications

    SciTech Connect

    Paton, C.G.; Bland, S.B.; Melley, R.E.

    1995-01-01

    This paper looks at four critical lubricants used in the conveyor systems of the northern Albertan oil sand facility. The requirements for the lubricants used in the electric motors and gear boxes of the drive systems, the pulley bearings and the idler bearings are discussed in terms of the application and the environment. A number of developments that have occurred in recent years are presented. Data from the field and from custom designed testing in the laboratory are used to support the role of simulation testing in problem solving in this area of technology. 9 refs., 21 figs.

  11. Mechanism of lubrication by tricresylphosphate (TCP)

    NASA Technical Reports Server (NTRS)

    Faut, O. D.; Buckley, D. H.

    1984-01-01

    The coefficient of friction was measured as a function of temperature on a pin-on-disk tribometer. Pins and disks of 440C and 52100 steels were lubricated with tricresylphosphate (TCP), 3.45 percent TCP in squalene, and pure squalene. The M-50 pins and disks were lubricated with 3.45 percent TCP in squalene and pure squalene. Experiments were conducted under limited lubrication conditions in dry ( 100 ppm H2O) air and dry ( pp H2O) nitrogen at 50 rpm (equivalent to a sliding velocity of 13 cm sec) and a constant load of 9.8 N (1 kg). Characteristic temperatures T sub r were identified for TCP on 52100 steel and for squalene on M-50 and 52100 steels, where the friction decreased because of a chemical reaction between the lubricant and the metal surface. The behavior of squalene obscured the influence of 3.45 percent TCP solute on the friction of the system. Wear volume measurements demonstrated that wear was lowest at temperatures just above T sub r. Comparing the behavior of TCP on M-50, 440C, and 52100 steels revealed that the TCP either reacted to give T sub r behavior or produced initial failure in the temperature range 223 + or - 5 C.

  12. Compliant Gripper for a Robotic Manipulator

    NASA Technical Reports Server (NTRS)

    Cipra, Raymond; Das, Hari

    2003-01-01

    A figure depicts a prototype of a robotic-manipulator gripping device that includes two passive compliant fingers, suitable for picking up and manipulating objects that have irregular shapes and/or that are, themselves, compliant. The main advantage offered by this device over other robotic-manipulator gripping devices is simplicity: Because of the compliance of the fingers, force-feedback control of the fingers is not necessary for gripping objects of a variety of sizes, shapes, textures, and degrees of compliance. Examples of objects that can be manipulated include small stones, articles of clothing, and parts of plants.

  13. Compliant Glass Seals for SOFC Stacks

    SciTech Connect

    Chou, Yeong -Shyung; Choi, Jung-Pyung; Xu, Wei; Stephens, Elizabeth V.; Koeppel, Brian J.; Stevenson, Jeffry W.; Lara-Curzio, Edgar

    2014-04-30

    This report summarizes results from experimental and modeling studies performed by participants in the Solid-State Energy Conversion Alliance (SECA) Core Technology Program, which indicate that compliant glass-based seals offer a number of potential advantages over conventional seals based on de-vitrifying glasses, including reduced stresses during stack operation and thermal cycling, and the ability to heal micro-damage induced during thermal cycling. The properties and composition of glasses developed and/or investigated in these studies are reported, along with results from long-term (up to 5,800h) evaluations of seals based on a compliant glass containing ceramic particles or ceramic fibers.

  14. Compliant Robot Wrist Senses Deflections And Forces

    NASA Technical Reports Server (NTRS)

    Purves, Lloyd R.; Strempek, Franklin; Premack, Timothy

    1989-01-01

    Precise parts assembled without damage. Goddard Space Flight Center developed compliant wrist that moves in any direction and rotates about any axis in response to applied forces. Deflection calibrated and instrumented so control computer measures degree of deflection and derives magnitude and direction of applied forces and torques. Compliant wrist brings to robots important capabilities humans use in manipulating objects. Helps prevent damage to precise, delicate parts during assembly by robot. Rod lengths, spring stiffnesses, and type of displacement sensor changed to suit different applications.

  15. Approach for Structurally Clearing an Adaptive Compliant Trailing Edge Flap for Flight

    NASA Technical Reports Server (NTRS)

    Miller, Eric J.; Lokos, William A.; Cruz, Josue; Crampton, Glen; Stephens, Craig A.; Kota, Sridhar; Ervin, Gregory; Flick, Pete

    2015-01-01

    The Adaptive Compliant Trailing Edge (ACTE) flap was flown on the National Aeronautics and Space Administration (NASA) Gulfstream GIII testbed at the NASA Armstrong Flight Research Center. This smoothly curving flap replaced the existing Fowler flaps creating a seamless control surface. This compliant structure, developed by FlexSys Inc. in partnership with the Air Force Research Laboratory, supported NASA objectives for airframe structural noise reduction, aerodynamic efficiency, and wing weight reduction through gust load alleviation. A thorough structures airworthiness approach was developed to move this project safely to flight. A combination of industry and NASA standard practice require various structural analyses, ground testing, and health monitoring techniques for showing an airworthy structure. This paper provides an overview of compliant structures design, the structural ground testing leading up to flight, and the flight envelope expansion and monitoring strategy. Flight data will be presented, and lessons learned along the way will be highlighted.

  16. Aeroelastic Response of the Adaptive Compliant Trailing Edge Transtition Section

    NASA Technical Reports Server (NTRS)

    Herrera, Claudia Y.; Spivey, Natalie D.; Lung, Shun-fat

    2016-01-01

    The Adaptive Compliant Trailing Edge demonstrator was a joint task under the Environmentally Responsible Aviation Project in partnership with the Air Force Research Laboratory and FlexSys, Inc. (Ann Arbor, Michigan), chartered by the National Aeronautics and Space Administration to develop advanced technologies that enable environmentally friendly aircraft, such as continuous mold-line technologies. The Adaptive Compliant Trailing Edge demonstrator encompassed replacing the Fowler flaps on the SubsoniC Aircraft Testbed, a Gulfstream III (Gulfstream Aerospace, Savannah, Georgia) aircraft, with control surfaces developed by FlexSys, Inc., a pair of uniquely-designed, unconventional flaps to be used as lifting surfaces during flight-testing to substantiate their structural effectiveness. The unconventional flaps consisted of a main flap section and two transition sections, inboard and outboard, which demonstrated the continuous mold-line technology. Unique characteristics of the transition sections provided a challenge to the airworthiness assessment for this part of the structure. A series of build-up tests and analyses were conducted to ensure the data required to support the airworthiness assessment were acquired and applied accurately. The transition sections were analyzed both as individual components and as part of the flight-test article assembly. Instrumentation was installed in the transition sections based on the analysis to best capture the in-flight aeroelastic response. Flight-testing was conducted and flight data were acquired to validate the analyses. This paper documents the details of the aeroelastic assessment and in-flight response of the transition sections of the unconventional Adaptive Compliant Trailing Edge flaps.

  17. Aeroelastic Airworthiness Assesment of the Adaptive Compliant Trailing Edge Flaps

    NASA Technical Reports Server (NTRS)

    Herrera, Claudia Y.; Spivey, Natalie D.; Lung, Shun-fat; Ervin, Gregory; Flick, Peter

    2015-01-01

    The Adaptive Compliant Trailing Edge (ACTE) demonstrator is a joint task under the National Aeronautics and Space Administration Environmentally Responsible Aviation Project in partnership with the Air Force Research Laboratory and FlexSys, Inc. (Ann Arbor, Michigan). The project goal is to develop advanced technologies that enable environmentally friendly aircraft, such as adaptive compliant technologies. The ACTE demonstrator flight-test program encompassed replacing the Fowler flaps on the SubsoniC Aircraft Testbed, a modified Gulfstream III (Gulfstream Aerospace, Savannah, Georgia) aircraft, with control surfaces developed by FlexSys. The control surfaces developed by FlexSys are a pair of uniquely-designed unconventional flaps to be used as lifting surfaces during flight-testing to validate their structural effectiveness. The unconventional flaps required a multidisciplinary airworthiness assessment to prove they could withstand the prescribed flight envelope. Several challenges were posed due to the large deflections experienced by the structure, requiring non-linear analysis methods. The aeroelastic assessment necessitated both conventional and extensive testing and analysis methods. A series of ground vibration tests (GVTs) were conducted to provide modal characteristics to validate and update finite element models (FEMs) used for the flutter analyses for a subset of the various flight configurations. Numerous FEMs were developed using data from FlexSys and the ground tests. The flap FEMs were then attached to the aircraft model to generate a combined FEM that could be analyzed for aeroelastic instabilities. The aeroelastic analysis results showed the combined system of aircraft and flaps were predicted to have the required flutter margin to successfully demonstrate the adaptive compliant technology. This paper documents the details of the aeroelastic airworthiness assessment described, including the ground testing and analyses, and subsequent flight

  18. Lubricating oil composition

    SciTech Connect

    Malec, R.E.

    1980-01-29

    The reaction product of (A) high molecular weight hydrocarbon-substituted phenols, (B) aldehydes, (C) ammonia or amines having a reactive hydrogen atom, and (D) alkylene oxides are effective dispersants for lubricating oil and impart detergent properties to liquid hydrocarbon fuels such as gasoline.

  19. 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...

  20. 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...

  1. Fundamentals of Solid Lubrication

    DTIC Science & Technology

    2012-03-01

    NOTES 14. ABSTRACT During this program, we have worked to develop a fundamental understanding of the chemical and tribological issues related to...approach, tribological measurements performed over a range of length scales, and the correlation of the two classes of information. Research activities...correlated measurements of surface composition and environmentally specific tribological performance of thin film solid lubricants. • Correlate shear

  2. 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...

  3. 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

  4. Compatibility of refrigerants and lubricants with elastomers. Final report

    SciTech Connect

    Hamed, G.R.; Seiple, R.H.; Taikum, Orawan

    1994-01-01

    The information contained in this report is designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. In part I of the program the swell behavior in the test fluids has been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 and 24 hours for samples removed fro the refrigerant test fluids and 24 hours after removal from the lubricants. Part II of the testing program includes the evaluation of tensile strength, hardness, weight, and dimensional changes after immersion aging in refrigerant/lubricant mixtures of selected elastomer formulations at elevated temperature and pressure.

  5. Adaptive Force Control in Compliant Motion

    NASA Technical Reports Server (NTRS)

    Seraji, H.

    1994-01-01

    This paper addresses the problem of controlling a manipulator in compliant motion while in contact with an environment having an unknown stiffness. Two classes of solutions are discussed: adaptive admittance control and adaptive compliance control. In both admittance and compliance control schemes, compensator adaptation is used to ensure a stable and uniform system performance.

  6. Hydrophobins as aqueous lubricant additive for a soft sliding contact.

    PubMed

    Lee, Seunghwan; Røn, Troels; Pakkanen, Kirsi I; Linder, Markus

    2015-01-01

    Two type II fungal hydrophobins, HFBI and FpHYD5, have been studied as aqueous lubricant additive at a nonpolar, compliant sliding contact (self-mated poly(dimethylsiloxane) (PDMS) contact) at two different concentrations, 0.1 mg/mL and 1.0 mg/mL. The two hydrophobins are featured as non-glycosylated (HFBI, m.w. ca. 7 kDa) vs glycosylated (FpHYD5, m.w. ca. 10 kDa) proteins. Far UV CD spectra of the two hydrophobins were very similar, suggesting overall structural similarity, but showed a noticeable difference according to the concentration. This is proposed to be related to the formation of multimers at 1.0 mg/mL. Despite 10-fold difference in the bulk concentration, the adsorbed masses of the hydrophobins onto PDMS surface obtained from the two solutions (0.1 and 1.0 mg/mL) were nearly identical, suggesting that a monolayer of the hydrophobins are formed from 0.1 mg/mL solution. PDMS-PDMS sliding interface was effectively lubricated by the hydrophobin solutions, and showed a reduction in the coefficient of friction by as much as ca. two orders of magnitude. Higher concentration solution (1.0 mg/mL) provided a superior lubrication, particularly in low-speed regime, where boundary lubrication characteristic is dominant via 'self-healing' mechanism. FpHYD5 revealed a better lubrication than HFBI presumably due to the presence of glycans and improved hydration of the sliding interface. Two type II hydrophobins function more favorably compared to a synthetic amphiphilic copolymer, PEO-PPO-PEO, with a similar molecular weight. This is ascribed to higher amount of adsorption of the hydrophobins to hydrophobic surfaces from aqueous solution.

  7. Lubrication of chocolate during oral processing.

    PubMed

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

    2017-02-22

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

  8. 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.

  9. 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.

  10. High temperature lubricant screening and systems studies

    NASA Technical Reports Server (NTRS)

    Jones, D. A.

    1973-01-01

    Four candidate lubricants for next generation aircraft gas turbine application were tested under open atmosphere conditions in a rig simulating an advanced engine 125 mm bore mainshaft thrust bearing position. Testing was conducted at speeds to 24,000 rpm (3,000,000 bearing DN), bearing ring temperature of 500 F, and with 1200 F air and 100 psi differential pressure across the seals installed in a dual tandem arrangement. Test bearing was a 125 mm bore split inner ring, outer race riding angular contact ball bearing under a 3280 lb. thrust load. One lubricant, a type 2 ester, performed extremely well. The mainshaft seal limited the performance. Numerous design improvements for this seal were indicated.

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. Polyurethane unicondylar knee prostheses: simulator wear tests and lubrication studies

    NASA Astrophysics Data System (ADS)

    Scholes, S. C.; Unsworth, A.; Jones, E.

    2007-01-01

    Many materials are used as artificial joint bearing surfaces; these include conventional stainless steel or CoCrMo-on-ultra-high molecular weight polyethylene (UHMWPE), CoCrMo on itself and alumina-on-alumina. However, these joints have a limited lifespan resulting in failure of the prosthesis and the need for revision surgery. A number of materials have been introduced recently in an attempt to overcome these problems. Polycarbonate urethane (PU) is a compliant material that can be used as an artificial joint bearing surface which has been developed to mimic the natural synovial joint more accurately by promoting fluid film lubrication. Tribological tests were performed on CoCrMo-on-PU unicondylar knee prostheses to assess their performance in vitro. The wear produced by these components was considerably lower than that found for conventional joints. They also exhibited low friction and operated close to full-fluid film lubrication with viscosities of lubricant similar to those found in patients with arthritis. These tests gave encouraging results for the tribological performance of this material couple for use as an alternative bearing combination.

  17. Polyurethane unicondylar knee prostheses: simulator wear tests and lubrication studies.

    PubMed

    Scholes, S C; Unsworth, A; Jones, E

    2007-01-07

    Many materials are used as artificial joint bearing surfaces; these include conventional stainless steel or CoCrMo-on-ultra-high molecular weight polyethylene (UHMWPE), CoCrMo on itself and alumina-on-alumina. However, these joints have a limited lifespan resulting in failure of the prosthesis and the need for revision surgery. A number of materials have been introduced recently in an attempt to overcome these problems. Polycarbonate urethane (PU) is a compliant material that can be used as an artificial joint bearing surface which has been developed to mimic the natural synovial joint more accurately by promoting fluid film lubrication. Tribological tests were performed on CoCrMo-on-PU unicondylar knee prostheses to assess their performance in vitro. The wear produced by these components was considerably lower than that found for conventional joints. They also exhibited low friction and operated close to full-fluid film lubrication with viscosities of lubricant similar to those found in patients with arthritis. These tests gave encouraging results for the tribological performance of this material couple for use as an alternative bearing combination.

  18. 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.

  19. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  20. 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.

  1. Lubricant Performance and Evaluation.

    DTIC Science & Technology

    1987-06-01

    responds to changes in concentration of ferromagnetic wear debris. A 5-gallon capacity microfiltration test rig was constructed to simulate fine filtration ...in turbine engine lubrication systems. A wear test machine was used to generate wear particles in order to study the impact of fine filtration on...Chromatogram of 0-79-17E from Squires Oxidative Test at 2050C after 24 Hours 76 29 Log Molecular Weight of Compounds I, II, III, and PANA vs Gel Permeation

  2. Selective Surface Modification on Lubricant Retention

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  3. HIPAA compliant auditing system for medical images.

    PubMed

    Zhou, Zheng; Liu, Brent J

    2005-01-01

    As an official regulation for healthcare privacy and security, Health Insurance Portability and Accountability Act (HIPAA) mandates health institutions to protect health information against unauthorized use or disclosure. One such method proposed by HIPAA Security Standards is audit trail, which records and examines health information access activities. HIPAA mandates healthcare providers to have the ability to generate audit trails on data access activities for any specific patient. Although current medical imaging systems generate activity logs, there is a lack of formal methodology to interpret these large volumes of log data and generate HIPAA compliant auditing trails. This paper outlines the design of a HIPAA compliant auditing system (HCAS) for medical images in imaging systems such as PACS and discusses the development of a security monitoring (SM) toolkit based on some of the partial components in HCAS.

  4. Method for designing and controlling compliant gripper

    NASA Astrophysics Data System (ADS)

    Spanu, A. R.; Besnea, D.; Avram, M.; Ciobanu, R.

    2016-08-01

    The compliant grippers are useful for high accuracy grasping of small objects with adaptive control of contact points along the active surfaces of the fingers. The spatial trajectories of the elements become a must, due to the development of MEMS. The paper presents the solution for the compliant gripper designed by the authors, so the planar and spatial movements are discussed. At the beginning of the process, the gripper could work as passive one just for the moment when it has to reach out the object surface. The forces provided by the elements have to avoid the damage. As part of the system, the camera is taken picture of the object, in order to facilitate the positioning of the system. When the contact is established, the mechanism is acting as an active gripper by using an electrical stepper motor, which has controlled movement.

  5. Compliant high temperature seals for dissimilar materials

    DOEpatents

    Rynders, Steven Walton; Minford, Eric; Tressler, Richard Ernest; Taylor, Dale M.

    2001-01-01

    A high temperature, gas-tight seal is formed by utilizing one or more compliant metallic toroidal ring sealing elements, where the applied pressure serves to activate the seal, thus improving the quality of the seal. The compliant nature of the sealing element compensates for differences in thermal expansion between the materials to be sealed, and is particularly useful in sealing a metallic member and a ceramic tube art elevated temperatures. The performance of the seal may be improved by coating the sealing element with a soft or flowable coating such as silver or gold and/or by backing the sealing element with a bed of fine powder. The material of the sealing element is chosen such that the element responds to stress elastically, even at elevated temperatures, permitting the seal to operate through multiple thermal cycles.

  6. Experimental determination of the rotor dynamic coefficients of a gas-lubricated foil journal bearing

    NASA Astrophysics Data System (ADS)

    Hurley, Keith Alan

    1998-12-01

    This thesis describes an experimental investigation of the dynamic stiffness and damping characteristics of an air lubricated leaf-type foil journal bearing. A test bed with dynamic force and response measurement capabilities has been designed and fabricated as a part of the research effort. The test bed consists of a two inch diameter rotor which is supported on two hydrostatic air bearings. The test bearing is centered on the test rotor. The test bed has rotor speed capability of up to 30,000 rpm. Transverse static and dynamic loads of up to 100 lbs can be applied to the test bearing. Direct and cross-coupled transverse stiffness and damping coefficients for a two inch diameter by two inch long eight-leaf foil bearing are obtained using a frequency domain estimation algorithm. Foil bearing dynamic coefficient data is presented for a range of average bearing loads, rotor speeds, and whirl frequency ratios. Experimental predictions of dynamic coefficients for a plain rigid test bearing have been obtained for test bed validation purposes. These experimental results are shown to be in good agreement with corresponding theoretical predictions of rigid bearing dynamic coefficients obtained using a linearized perturbation analysis method. Simulated data has been used to investigate the effects of sensor calibration error and quantization error on the prediction of dynamic coefficients. The results of these investigations are also presented. A rotordynamic analysis is also presented and demonstrates how the dynamic coefficient data can be used to obtain a quantitative assessment of rotor/bearing system stability and frequency response characteristics. Dynamic response characteristics for rigid and compliant surface bearings are compared. The results substantiate the notion that foil bearings have enhanced dynamic performance characteristics in comparison to their rigid bearing counterparts.

  7. Comparison of the weight loss and adherence of nine different polyimide films thermally aged at 315 C and 350 C in air. [high temperature lubricants

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.

    1980-01-01

    Thermal exposure experiments at 315 and 350 C were performed in air on nine different types of polyimides applied to thin 304 stainless steel foils. The tests were conducted to determine which polyimide was the most thermally stable and adherent when subjected to long exposure times at elevated temperatures. One polyimide designated PIC-7 was found to be more thermally stable than the others; however, it did not possess the adherent properties of PIC-2 and PIC-5. It was concluded that as far as thermal stability and adherence are concerned, five of the polyimides are more suitable for high temperature applications than the other four.

  8. Ceramic TBS/porous metal compliant layer

    NASA Technical Reports Server (NTRS)

    Tolokan, Robert P.; Jarrabet, G. P.

    1992-01-01

    Technetics Corporation manufactures metal fiber materials and components used in aerospace applications. Our technology base is fiber metal porous sheet material made from sinter bonded metal fibers. Fiber metals have percent densities (metal content by volume) from 10 to 65 percent. Various topics are covered and include the following: fiber metal materials, compliant layer thermal bayer coatings (TBC's), pad properties, ceramic/pad TBC design, thermal shock rig, fabrication, and applications.

  9. JCID Compliant Thin Server for Sensors

    DTIC Science & Technology

    2008-10-01

    JCID SST Insertion Project (JSP) is a team effort between a group at Penn State’s Applied Research Lab and Lattice/RTI of Herndon, VA to integrate a...Applied Research Lab and Lattice/RTI of Herndon, VA to integrate a flexible table-based sensor configuration capability into the the JCID/JWARN...ARO JCID Compliant Thin Server for Sensors D.C. Swanson The Applied Research Laboratory The Pennsylvania State University POB 30 State College

  10. Characterization and modeling of compliant active materials

    NASA Astrophysics Data System (ADS)

    Marra, S. P.; Ramesh, K. T.; Douglas, A. S.

    2003-09-01

    Active materials respond mechanically to changes in environmental conditions. One example of a compliant active material is a polymer gel. Active polymer gels expand and contract in response to certain environmental stimuli, such as the application of an electric field or a change in the pH level of the surroundings. This ability to achieve large, reversible deformations with no external mechanical loading has generated much interest in the use of these gels as actuators and "artificial muscles". While much work has been done to study the behavior and properties of these gels, little information is available regarding the full constitutive description of the mechanical and actuation properties. This work focuses on developing a means of characterizing the mechanical properties of compliant active materials. A thermodynamically consistent finite-elastic constitutive model was developed to describe the mechanical and actuation behaviors of these kinds of materials. The mechanical properties of compliant active materials are characterized by a free-energy function, and the model utilizes an evolving internal variable to describe the actuation state. A biaxial testing system has been developed which can measure stresses and deformations of polymer gel films in a variety of liquid environments. This testing system is used to determine the form and parameters of the free-energy function for a specific active polymer gel, poly(vinyl alcohol)-poly(acrylic acid) gel.

  11. Optimizing power cylinder lubrication on a large bore natural gas engine

    NASA Astrophysics Data System (ADS)

    Luedeman, Matthew R.

    More than 6000 integral compressors, located along America's natural gas pipelines, pump natural gas across the United States. These compressors are powered by 2-stroke, large bore natural gas burning engines. Lowering the operating costs, reducing the emissions, and ensuring that these engines remain compliant with future emission regulations are the drivers for this study. Substantial research has focused on optimizing efficiency and reducing the fuel derived emissions on this class of engine. However, significantly less research has focused on the effect and reduction of lubricating oil derived emissions. This study evaluates the impact of power cylinder lubricating oil on overall engine emissions with an emphasis on reducing oxidation catalyst poisoning. A traditional power cylinder lubricator was analyzed; power cylinder lubricating oil was found to significantly impact exhaust emissions. Lubricating oil was identified as the primary contributor of particulate matter production in a large bore natural gas engine. The particulate matter was determined to be primarily organic carbon, and most likely direct oil carryover of small oil droplets. The particulate matter production equated to 25% of the injected oil at a nominal power cylinder lubrication rate. In addition, power cylinder friction is considered the primary contributor to friction loss in the internal combustion engine. This study investigates the potential for optimizing power cylinder lubrication by controlling power cylinder injection to occur at the optimal time in the piston cycle. By injecting oil directly into the ring pack, it is believed that emissions, catalyst poisoning, friction, and wear can all be reduced. This report outlines the design and theory of two electronically controlled lubrication systems. Experimental results and evaluation of one of the systems is included.

  12. 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.

  13. A Comparison of the Lubricating Mechanisms of Graphite Fluoride and Molybdenum Disulfide Films

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.

    1978-01-01

    A microscopic study of 440C steel sliding surfaces lubricated by graphite fluoride or molybdenum disulfide solid lubricant rubbed films was conducted. The sliding surfaces, along with the friction, wear, and wear life were observed as a function of the number of sliding revolutions in three different atmospheres: moist air, dry air, or dry argon. In general, the lubricating mechanisms of the two solid lubricants were found to be relatively similar; that is, a dynamic, thin, layer-like film was formed between the two metallic surfaces. The mechanisms of failure were found to be somewhat different, however. Failure of MoS2 films was very dependent on atmospheric degradation, while that of graphite fluoride films was more dependent on flow of the lubricant film out of the contact zone.

  14. A comparison of the lubricating mechanisms of graphite fluoride and molybdenum disulfide films

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.

    1978-01-01

    A microscopic study of 440 C steel sliding surfaces lubricated by graphite fluoride or molybdenum disulfide solid lubricant rubbed films was conducted. The sliding surfaces, along with the friction, wear, and wear life were observed as a function of the number of sliding revolutions in three different atmospheres: moist air (10,000 ppm H2O), dry air (less than 20 ppm H2O), or dry argon (less than 20 ppm H2O). In general, the lubricating mechanisms of the two solid lubricants were found to be relatively similar; that is, a dynamic, thin, layer-like film (which sheared on relative motion) was formed between the two metallic surfaces. The mechanisms of failure were found to be somewhat different, however. Failure of MoS2 films was very dependent on atmospheric degradation, while that of graphite fluoride films was more dependent on flow of the lubricant film out of the contact zone

  15. Oxidation and frictional performance of solid lubricants used in weapon stronglinks

    SciTech Connect

    Dugger, M.T.; Peebles, D.E.; Ohlhausen, J.A.; Varga, K.S.; Steinhoff, R.

    1996-05-01

    The oxidation and performance of the solid film lubricant used in a majority of the surety devices in the enduring stockpile have been investigated. Oxidation of this lubricant in air at 150 C produces a significant increase in the molybdenum oxide to sulfide ratio, indicative of degradation of the primary lubricating constituent of the composite lubricant. Oxidation is more extensive on samples that were burnished such that the substrate is exposed over a fraction of the surface, relative to those which were only lightly burnished. Friction results indicate that oxidation in air did not increase the initial or steady-state friction coefficient for lightly burnished surfaces. However, surfaces burnished to expose substrate material experienced a significant increase in both initial and steady-state friction. Oxidation of lubricated parts retrieved from aged stronglinks has also been demonstrated.

  16. 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.

  17. 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.

  18. Compliant Metal Enhanced Convection Cooled Reverse-Flow Annular Combustor

    NASA Technical Reports Server (NTRS)

    Paskin, Marc D.; Acosta, Waldo A.

    1994-01-01

    A joint Army/NASA program was conducted to design, fabricate, and test an advanced, reverse-flow, small gas turbine combustor using a compliant metal enhanced (CME) convection wall cooling concept. The objectives of this effort were to develop a design method (basic design data base and analysis) for the CME cooling technique and tben demonstrate its application to an advanced cycle, small, reverse-flow combustor with 3000 F (1922 K) burner outlet temperature (BOT). The CME concept offers significant improvements in wall cooling effectiveness resulting in a large reduction in cooling air requirements. Therefore, more air is available for control of burner outlet temperature pattern in addition to the benefit of improved efficiency, reduced emissions, and smoke levels. Rig test results demonstrated the benefits and viability of the CME concept meeting or exceeding the aerothermal performance and liner wall temperature characteristics of similar lower temperature-rise combustors, achieving 0.15 pattern factor at 3000 F (1922 K) BOT, while utilizing approximately 80 percent less cooling air than conventional, film-cooled combustion systems.

  19. Metal-containing lubricant compositions

    SciTech Connect

    Hunt, M.W.; Kennedy, S.

    1987-05-12

    A lubricating oil composition is described comprising: a major amount of a lubricating oil; from 1 to 10 (wt)% of an ashless dispersant compound; or from 0.3 to 10 (wt)% of a nitrogen or ester containing polymeric viscosity index improver dispersant.

  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. Detergent Additive for Lubricating Oils,

    DTIC Science & Technology

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

  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. Flight Testing of Novel Compliant Spines for Passive Wing Morphing on Ornithopters

    NASA Technical Reports Server (NTRS)

    Wissa, Aimy; Guerreiro, Nelson; Grauer, Jared; Altenbuchner, Cornelia; Hubbard, James E., Jr.; Tummala, Yashwanth; Frecker, Mary; Roberts, Richard

    2013-01-01

    Unmanned Aerial Vehicles (UAVs) are proliferating in both the civil and military markets. Flapping wing UAVs, or ornithopters, have the potential to combine the agility and maneuverability of rotary wing aircraft with excellent performance in low Reynolds number flight regimes. The purpose of this paper is to present new free flight experimental results for an ornithopter equipped with one degree of freedom (1DOF) compliant spines that were designed and optimized in terms of mass, maximum von-Mises stress, and desired wing bending deflections. The spines were inserted in an experimental ornithopter wing spar in order to achieve a set of desired kinematics during the up and down strokes of a flapping cycle. The ornithopter was flown at Wright Patterson Air Force Base in the Air Force Research Laboratory Small Unmanned Air Systems (SUAS) indoor flight facility. Vicon motion tracking cameras were used to track the motion of the vehicle for five different wing configurations. The effect of the presence of the compliant spine on wing kinematics and leading edge spar deflection during flight is presented. Results show that the ornithopter with the compliant spine inserted in its wing reduced the body acceleration during the upstroke which translates into overall lift gains.

  4. Lubricant film flow and depletion characteristics at head/disk storage interface

    NASA Astrophysics Data System (ADS)

    Ao, Hong-Rui; Han, Zhi-Ying; Zhang, Kai; Jiang, Hong-Yuan

    2016-12-01

    The characteristics of lubricant film at head/disk interface (HDI) are essential to the stability of hard disk drives. In this study, the theoretical models of the lubricant flow and depletion are deduced based on Navier-Stokes (NS) and continuity equations. The air bearing pressure on the surface of the lubrication film is solved by the modified Reynolds equation based on Fukui and Kaneko (FK) model. Then the lubricant film deformations for a plane slider and double-track slider are obtained. The equation of lubricant film thickness is deduced with the consideration of van der Waals force, the air bearing pressure, the surface tension, and the external stresses. The lubricant depletion under heat source is simulated and the effects of different working conditions including initial thickness, flying height and the speed of the disk on lubricant depletion are discussed. The main factors that cause the lubricant flow and depletion are analyzed and the ways to reduce the film thickness deformation are proposed. The simulation results indicate that the shearing stress is the most important factor that causes the thickness deformation and other terms listed in the equation have little influence. The thickness deformation is dependent on the working parameter, and the thermal condition evaporation is the most important factor. Project supported by the National Natural Science Foundation of China (Grant No. 51275124).

  5. Mounting with compliant cylinders for deformable mirrors.

    PubMed

    Reinlein, Claudia; Goy, Matthias; Lange, Nicolas; Appelfelder, Michael

    2015-04-01

    A method is presented to mount large aperture unimorph deformable mirrors by compliant cylinders (CC). The CCs are manufactured from a soft silicone, and shear testing is performed in order to evaluate the Young's modulus. A scale mirror model is assembled to evaluate mount-induced change of piezoelectric deformation, and its applicability for tightly focusing mirrors. Experiments do not show any decrease of piezoelectric stroke. Further it is shown that the changes of surface fidelity by the attachment of the deformable mirror to its mount are neglectable.

  6. VO-compliant workflows and science gateways

    NASA Astrophysics Data System (ADS)

    Castelli, G.; Taffoni, G.; Sciacca, E.; Becciani, U.; Costa, A.; Krokos, M.; Pasian, F.; Vuerli, C.

    2015-06-01

    Workflow and science gateway technologies have been adopted by scientific communities as a valuable tool to carry out complex experiments. They offer the possibility to perform computations for data analysis and simulations, whereas hiding details of the complex infrastructures underneath. There are many workflow management systems covering a large variety of generic services coordinating execution of workflows. In this paper we describe our experiences in creating workflows oriented science gateways based on gUSE/WS-PGRADE technology and in particular we discuss the efforts devoted to develop a VO-compliant web environment.

  7. Compliant sleeve for ceramic turbine blades

    DOEpatents

    Cai, Hongda; Narasimhan, Dave; Strangman, Thomas E.; Easley, Michael L.; Schenk, Bjoern

    2000-01-01

    A compliant sleeve for attaching a ceramic member to a metal member is comprised of a superalloy substrate having a metal contacting side and a ceramic contacting side. The ceramic contacting side is plated with a layer of nickel followed by a layer of platinum. The substrate is then oxidized to form nickel oxide scale on the ceramic contacting side and a cobalt oxide scale on the metal contacting side. A lubricious coating of boron nitride is then applied over the metal contacting side, and a shear-stress limiting gold coating is applied over the ceramic contacting side.

  8. Design of 3D-Printed Titanium Compliant Mechanisms

    NASA Technical Reports Server (NTRS)

    Merriam, Ezekiel G.; Jones, Jonathan E.; Howell, Larry L.

    2014-01-01

    This paper describes 3D-printed titanium compliant mechanisms for aerospace applications. It is meant as a primer to help engineers design compliant, multi-axis, printed parts that exhibit high performance. Topics covered include brief introductions to both compliant mechanism design and 3D printing in titanium, material and geometry considerations for 3D printing, modeling techniques, and case studies of both successful and unsuccessful part geometries. Key findings include recommended flexure geometries, minimum thicknesses, and general design guidelines for compliant printed parts that may not be obvious to the first time designer.

  9. 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...

  10. 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...

  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 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...

  13. 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...

  14. 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.

  15. Towards an optimised sputtered MoS2 lubricant film

    NASA Technical Reports Server (NTRS)

    Roberts, E. W.

    1986-01-01

    It is shown that the tribological quality of MoS2 lubricant films formed by magnetron sputtering is determined by the choice of sputtering conditions. By selecting the appropriate conditions, films of extremely high lubricity and endurance (in vacuum), which are well suited to many space applications, are obtained. Such MoS2 films, when applied to precision ball hearings, give rise to the lowest torques (for the given test conditions) yet seen in our laboratory. While a remarkably good performance is obtained in vacuum, tests in air show a marked deterioration in lubricating qualities. It is demonstrated that this is attributable to the adsorption of water vapor on MoS2 surfaces and that the degree of deterioration is related to the partial pressure of water vapor present. Analysis of results indicates that the factors relevant to obtaining optimum films are deposition rate and film composition.

  16. Wetting of a partially immersed compliant rod

    NASA Astrophysics Data System (ADS)

    Hui, Chung-Yuen; Jagota, Anand

    2016-11-01

    The force on a solid rod partially immersed in a liquid is commonly used to determine the liquid-vapor surface tension by equating the measured force required to remove the rod from the liquid to the vertical component of the liquid-vapor surface tension. Here, we study how this process is affected when the rod is compliant. For equilibrium, we enforce force and configurational energy balance, including contributions from elastic energy. We show that, in general, the contact angle does not equal that given by Young's equation. If surface stresses are tensile, the strain in the immersed part of the rod is found to be compressive and to depend only on the solid-liquid surface stress. The strain in the dry part of the rod can be either tensile or compressive, depending on a combination of parameters that we identify. We also provide results for compliant plates partially immersed in a liquid under plane strain and plane stress. Our results can be used to extract solid surface stresses from such experiments.

  17. Shape-memory-actuated compliant control surface

    NASA Astrophysics Data System (ADS)

    Maclean, Brian J.; Carpenter, Bernie F.; Draper, Jerry L.; Misra, Mohan S.

    1993-09-01

    Advanced submarine stern configurations require a variety of control surfaces to actively manage aftbody boundary layer flow, vorticity, propulsor inflow and intrapropulsor flow, as well as vehicle attitude. Two necessary attributes of advanced control surface designs include (1) integrated actuation to provide placement flexibility at remote locations with minimal structural interfacing and control interconnects, and (2) improved lift efficiency and flow using variable or adaptive camber control. To demonstrate these attributes, a shape memory alloy (SMA) actuated compliant control fin (CCF) with a planform area of 620 sq. cm was developed for evaluation as rudder and sternplane appendages on a radio control submarine model at velocities up to 5.1 m/s (Reynolds No. approximately equals 1,000,000) and up to 0.2 Hz full cycle actuation. A completely fixed root design was developed to reduce turbulence at the hull/fine interface, with compliant deformation of the foil to improve flow characteristics over the baseline full-flying and trailing-edge-flap designs.

  18. Bionic robot arm with compliant actuators

    NASA Astrophysics Data System (ADS)

    Moehl, Bernhard

    2000-10-01

    Traditional robotics uses non-compliant materials for all components involved in the production of movement. Elasticity is avoided as far as possible, because it leads to hazardous oscillations and makes control of precise movements very difficult. Due to this deliberate stiffness, robots are typically heavy and clumsy structures in comparison to their living counterparts (i.e. man and animals). Yet, moving systems in nature cope not only with the difficulties introduced by compliant materials, they also take advantage of the elasticity in muscles and tendons to produce smooth and even rapid movements. It is understood, that elasticity in a multi-jointed moving system requires sophisticated control mechanisms- as provided by a nervous system or a suitably programmed computer. In this contribution I shall describe a two-jointed robot with purpose-built elasticity in its actuators. This is accomplished by spiral springs places in series with a conventional electric motor and a tendon to the arm. It is shown that, with sufficiently soft elasticity, oscillations can be avoided by active oscillation damping. (Such active oscillation damping presumably also governs movement control in man and animals.) Furthermore, once the major problem has been overcome, elasticity is found to offer a wide spectrum of valuable advantages, as far as the most serious problems in traditional robotics are concerned. They are summarized by terms such as less dangerous, position tolerant, lightweight construction, controlled forces, and ballistic movements. These will be explained in detail and presented for discussion.

  19. 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.

  20. 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.

  1. Green waxes, adhesives and lubricants.

    PubMed

    Li, W; Kong, X H; Ruan, M; Ma, F M; Jiang, Y F; Liu, M Z; Chen, Y; Zuo, X H

    2010-10-28

    General characteristics of waxes, adhesives and lubricants as well as the recent fundamental investigations on their physical and mechanical behaviour are introduced. The current R&D status for new type/generation of waxes, adhesives and lubricants from natural products is reviewed, with an emphasis on their tribological applications. In particular, some crucial issues and challenges relating to technological improvement and materials development are discussed. Based on the current predicted shortage of energy resources and environmental concerns, prospective research on the development of green waxes, adhesives and lubricants is suggested.

  2. 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..

  3. 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.

  4. 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.

  5. Lubricant retention for liquid infused surfaces exposed to turbulent flow

    NASA Astrophysics Data System (ADS)

    Fu, Matthew; Hultmark, Marcus

    2015-11-01

    Liquid infused surfaces have been proposed as a robust alternative to traditional, air-filled superhydrophobic surfaces. The mobility of the liquid lubricant facilitates a surface slip with the outer turbulent shear flow. However, shear driven drainage in turbulent flow has been found to be a primary failure mechanism for such surfaces, resulting in loss of lubricant and the associated slip effect. A turbulent channel flow facility is used to characterize shear-driven drainage behavior of liquid infused micro-patterned surfaces. Micro-manufactured surfaces can be mounted flush in the channel and exposed to turbulent flows. The retention of fluorescent lubricants is monitored to characterize how surface geometry and lubricant properties affect the steady state retention length. Results are compared with theoretical predictions and experiments for lubricant retention in laminar microchannels, where the shear driven drainage is balanced by a Laplace pressure gradient, to determine the additional drainage induced by turbulent fluctuations. Supported under ONR Grants N00014-12-1-0875 and N00014-12-1-0962 (program manager Ki-Han Kim).

  6. Compatibility of refrigerants and lubricants with engineering plastics. Final report

    SciTech Connect

    Cavestri, R.C.

    1993-12-01

    23 plastics have been subjected to immersion studies using 7 different lubricants at 60 C and 100 C, and 10 different refrigerants at ambient and 60 C. In the first part of the study, 22 hermetic stress crack-creep rupture test chambers were used to determine dynamic effects of a constant dead weight load on plastic test bars immersed at 20 C in a 40% refrigerant 32 ISOVG branched acid polyolester lubricant. The creep modulus data of the 10 refrigerants, using a dead weight load of 25% of ultimate tensile, are compared to values for air and HCFC-22. In the second part, the plastic test bars were aged for 14 d at constant refrigerant pressure 300 psia with 17 refrigerant lubricant combinations at 150 C. Additional evaluations were conducted to elucidate the effects of temperature, refrigerant, and lubricant on the plastics. At 150 C, high acid formation (high TAN) was further examined with dehydrated plastics. These evaluations indicate that dehydrating the plastics reduced, but did not eliminate, high TAN values and that heat alone caused the lost physicals. Alternative HFC refrigerants had little impact on plastics; some polyolester lubricants caused identifiable changes.

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  8. Lubrication by Diamond and Diamondlike Carbon Coatings

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1997-01-01

    Regardless of environment (ultrahigh vacuum, humid air, dry nitrogen, or water), ion-beam-deposited diamondlike carbon (DLC) and nitrogen-ion-implanted, chemical-vapor-deposited (CVD) diamond films had low steady-state coefficients of friction (less than 0.1) and low wear rates (less than or equal to 10(exp -6)cu mm/N(dot)m). These films can be used as effective wear-resistant, self-lubricating coatings regardless of environment. On the other hand, as-deposited, fine-grain CVD diamond films; polished, coarse-grain CVD diamond films; and polished and then fluorinated, coarse-grain CVD diamond films can be used as effective wear-resistant, self-lubricating coatings in humid air, in dry nitrogen, and in water, but they had a high coefficient of friction and a high wear rate in ultrahigh vacuum. The polished, coarse-grain CVD diamond film revealed an extremely low wear rate, far less than 10(exp 10) cu mm/N(dot)m, in water.

  9. Kinematic primitives for walking and trotting gaits of a quadruped robot with compliant legs

    PubMed Central

    Spröwitz, Alexander T.; Ajallooeian, Mostafa; Tuleu, Alexandre; Ijspeert, Auke Jan

    2014-01-01

    In this work we research the role of body dynamics in the complexity of kinematic patterns in a quadruped robot with compliant legs. Two gait patterns, lateral sequence walk and trot, along with leg length control patterns of different complexity were implemented in a modular, feed-forward locomotion controller. The controller was tested on a small, quadruped robot with compliant, segmented leg design, and led to self-stable and self-stabilizing robot locomotion. In-air stepping and on-ground locomotion leg kinematics were recorded, and the number and shapes of motion primitives accounting for 95% of the variance of kinematic leg data were extracted. This revealed that kinematic patterns resulting from feed-forward control had a lower complexity (in-air stepping, 2–3 primitives) than kinematic patterns from on-ground locomotion (νm4 primitives), although both experiments applied identical motor patterns. The complexity of on-ground kinematic patterns had increased, through ground contact and mechanical entrainment. The complexity of observed kinematic on-ground data matches those reported from level-ground locomotion data of legged animals. Results indicate that a very low complexity of modular, rhythmic, feed-forward motor control is sufficient for level-ground locomotion in combination with passive compliant legged hardware. PMID:24639645

  10. 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

  11. Environmentally friendly and biobased lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  12. Structural lubricity under ambient conditions

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    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.

  13. Method for lubricating contacting surfaces

    DOEpatents

    Dugger, Michael T [Tijeras, NM; Ohlhausen, James A [Albuquerque, NM; Asay, David B [Boalsburg, PA; Kim, Seong H [State College, PA

    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.

  14. A survey of bio-inspired compliant legged robot designs.

    PubMed

    Zhou, Xiaodong; Bi, Shusheng

    2012-12-01

    The roles of biological springs in vertebrate animals and their implementations in compliant legged robots offer significant advantages over the rigid legged ones in certain types of scenarios. A large number of robotics institutes have been attempting to work in conjunction with biologists and incorporated these principles into the design of biologically inspired robots. The motivation of this review is to investigate the most published compliant legged robots and categorize them according to the types of compliant elements adopted in their mechanical structures. Based on the typical robots investigated, the trade-off between each category is summarized. In addition, the most significant performances of these robots are compared quantitatively, and multiple available solutions for the future compliant legged robot design are suggested. Finally, the design challenges for compliant legged robots are analysed. This review will provide useful guidance for robotic designers in creating new designs by inheriting the virtues of those successful robots according to the specific tasks.

  15. Lubricating and wear mechanisms for a hemisphere sliding on polyimide-bonded graphite fluoride film

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.

    1979-01-01

    Friction, wear life, rider wear, and film wear for a 440 C high-temperature-stainless-steel, hemispherically tipped rider sliding against polyimide-bonded graphite fluoride films were evaluated in a moist-air atmosphere at 25 C. Optical microscope and surface profilometry observations were made at various sliding intervals to determine how film thickness affected the lubricating and failure mechanisms of the films. Two lubrication regimes operated for the same load. In the first, the film supported the load and the lubricating mechanism consisted of the shear (plastic flow) of a thin layer of the lubricant between the metallic rider and the film surface. In the second, the film did not support the load (it was worn away) and the lubricating mechanism consisted of the shear of very thin lubricant films between flat areas generated on the rider and on sandblasted metallic asperities in the film wear track. Lubricant was supplied from the valleys between the asperities or from the sides of the wear track. With thicker films, wear life increased since a greater lubricant supply was available from the sides of the wear track.

  16. Miscibility of lubricants with refrigerants

    SciTech Connect

    Pate, M.B.; Zoz, S.C.; Berkenbosch, L.J.

    1992-07-01

    Miscibility data is being obtained for a variety of non-CFC refrigerants and their potential lubricants. Ten different refrigerants and seven different lubricants are being investigated. Experiments are being performed in two phases: Phase I focuses on performing screening tests and Phase II consists of developing miscibility plots. The miscibility tests are being performed in a test facility consisting of a series of miniature test cells submerged in a constant temperature bath. The bath temperature can be precisely controlled over a temperature range of -50{degrees}C to 100{degrees}C. The test cells are constructed to allow for complete visibility of lubricant-refrigerant mixtures under all test conditions. Early in this reporting period, new procedures for charging the lubricant and refrigerant into the cells for testing were adopted. All of the refrigerants and all but one of the lubricants have been received from the manufacturers. Data obtained to date includes that for R-134a, R142b, R-32, R-134, R-125, and R-143a with four lubricants, namely, two esters and two polypropylene glycols.

  17. Air-lubrication of magnetic disk sliders

    NASA Astrophysics Data System (ADS)

    Dreßler, B.; Graichen, K.; Bärwolff, G.; Jehring, L.; Seifert, G.

    1993-03-01

    Steady-state and dynamic flying of a self-acting magnetic disk slider over a hard disk are considered. Some tasks for computations are formulated and the possibilities of developed numerical codes are illustrated. Numerical results of dynamic flying over a disk surface with an obstacle are in agreement with experimental data.

  18. Nanomechanics of hard films on compliant substrates.

    SciTech Connect

    Reedy, Earl David, Jr.; Emerson, John Allen; Bahr, David F.; Moody, Neville Reid; Zhou, Xiao Wang; Hales, Lucas; Adams, David Price; Yeager,John; Nyugen, Thao D.; Corona, Edmundo; Kennedy, Marian S.; Cordill, Megan J.

    2009-09-01

    Development of flexible thin film systems for biomedical, homeland security and environmental sensing applications has increased dramatically in recent years [1,2,3,4]. These systems typically combine traditional semiconductor technology with new flexible substrates, allowing for both the high electron mobility of semiconductors and the flexibility of polymers. The devices have the ability to be easily integrated into components and show promise for advanced design concepts, ranging from innovative microelectronics to MEMS and NEMS devices. These devices often contain layers of thin polymer, ceramic and metallic films where differing properties can lead to large residual stresses [5]. As long as the films remain substrate-bonded, they may deform far beyond their freestanding counterpart. Once debonded, substrate constraint disappears leading to film failure where compressive stresses can lead to wrinkling, delamination, and buckling [6,7,8] while tensile stresses can lead to film fracture and decohesion [9,10,11]. In all cases, performance depends on film adhesion. Experimentally it is difficult to measure adhesion. It is often studied using tape [12], pull off [13,14,15], and peel tests [16,17]. More recent techniques for measuring adhesion include scratch testing [18,19,20,21], four point bending [22,23,24], indentation [25,26,27], spontaneous blisters [28,29] and stressed overlayers [7,26,30,31,32,33]. Nevertheless, sample design and test techniques must be tailored for each system. There is a large body of elastic thin film fracture and elastic contact mechanics solutions for elastic films on rigid substrates in the published literature [5,7,34,35,36]. More recent work has extended these solutions to films on compliant substrates and show that increasing compliance markedly changes fracture energies compared with rigid elastic solution results [37,38]. However, the introduction of inelastic substrate response significantly complicates the problem [10,39,40]. As

  19. TIDAL TURBULENCE SPECTRA FROM A COMPLIANT MOORING

    SciTech Connect

    Thomson, Jim; Kilcher, Levi; Richmond, Marshall C.; Talbert, Joe; deKlerk, Alex; Polagye, Brian; Guerra, Maricarmen; Cienfuegos, Rodrigo

    2013-06-13

    A compliant mooring to collect high frequency turbulence data at a tidal energy site is evaluated in a series of short demon- stration deployments. The Tidal Turbulence Mooring (TTM) improves upon recent bottom-mounted approaches by suspend- ing Acoustic Doppler Velocimeters (ADVs) at mid-water depths (which are more relevant to tidal turbines). The ADV turbulence data are superior to Acoustic Doppler Current Profiler (ADCP) data, but are subject to motion contamination when suspended on a mooring in strong currents. In this demonstration, passive stabilization is shown to be sufficient for acquiring bulk statistics of the turbulence, without motion correction. With motion cor- rection (post-processing), data quality is further improved; the relative merits of direct and spectral motion correction are dis- cussed.

  20. 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.

  1. 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.

  2. Boundary cartilage lubrication: review of current concepts.

    PubMed

    Daniel, Matej

    2014-03-01

    Effective lubrication of synovial joints is important to prevent cartilage degeneration and to keep the joints healthy. This paper sets out the basics of engineering lubrication with respect to the composition and properties of synovial fluid constituents. Two basic types of boundary lubrication are discussed: the presence of highly hydrophilic proteoglycans that provide a water liquid film, and the existence of multilamellar phospholipids lubricating layers at the surface ofarticular cartilage. Based on current knowledge, we may conclude that no single mechanism of boundary lubrication exists, and that effective boundary lubrication of synovial joints is maintained by the synergic effect of all synovial fluid constituents.

  3. Pulsed Plasma Lubrication Device and Method

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

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

  4. 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.

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

    PubMed

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

    2017-03-01

    The glycoprotein, lubricin, is the primary boundary lubricant of articular cartilage and has been shown to prevent cartilage damage after joint injury. In this study, a library of eight bottle-brush copolymers were synthesized to mimic the structure and function of lubricin. Polyethylene glycol (PEG) grafted onto a polyacrylic acid (pAA) core mimicked the hydrophilic mucin-like domain of lubricin, and a thiol terminus anchored the polymers to cartilage surfaces much like lubricin's C-terminus. These copolymers, abbreviated as pAA-g-PEG, rapidly bound to cartilage surfaces with binding time constants ranging from 20 to 39 min, and affected lubrication under boundary mode conditions with coefficients of friction ranging from 0.140 ± 0.024 to 0.248 ± 0.030. Binding and lubrication were highly correlated (r(2)  = 0.89-0.99), showing that boundary lubrication in this case strongly depends on the binding of the lubricant to the surface. Along with time-dependent and dose-dependent behavior, lubrication and binding of the lubricin-mimetics also depended on copolymer structural parameters including pAA backbone length, PEG side chain length, and PEG:AA brush density. Polymers with larger backbone sizes, brush sizes, or brush densities took longer to bind (p < 0.05). Six of the eight polymers reduced friction relative to denuded cartilage plugs (p < 0.05), suggesting their potential to lubricate and protect cartilage in vivo. In copolymers with shorter pAA backbones, increasing hydrodynamic size inhibited lubrication (p < 0.08), while the opposite was observed in copolymers with longer backbones (p < 0.05). These polymers show similar in vitro lubricating efficacy as recombinant lubricins and as such have potential for in vivo treatment of post-traumatic osteoarthritis. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:548-557, 2017.

  6. New nanotechnology solid lubricants for superior dry lubrication

    NASA Astrophysics Data System (ADS)

    Fleischer, N.; Genut, M.; Rapoport, L.; Tenne, R.

    2003-09-01

    This paper presents a new commercial breakthrough for advanced anti-friction materials based on unique inorganic nanospheres that can be used as dry lubricants, coatings, and for impregnating parts. The new material reduces friction and wear significantly better than other layered solid lubricants and is especially useful in self-lubricating, maintenance-free, and oil-free applications of the types encountered in aerospace markets. The material, NanoLubTM, is the world's first commercial lubricant based on spherical inorganic nanoparticles. NanoLub's particles have a unique structure of hollow nested spheres of about only 0.1 micron in diameter. This paper presents tribological evaluations of tungsten and molybdenum disulphide NanoLubTM. The material reduces friction and wear under conditions that are especially relevant for space such as ultra-high vacuum, UV radiation, and high loads. Suitable applications could include rotors, bearings, robots, planetary rovers, space vehicles and transport devices. Extensive testing by a number of independent groups clearly shows that these special nanoparticles improve considerably the tribological properties of different contact pairs in comparison to other solid lubricants.

  7. Membrane muscle function in the compliant wings of bats.

    PubMed

    Cheney, J A; Konow, N; Middleton, K M; Breuer, K S; Roberts, T J; Giblin, E L; Swartz, S M

    2014-06-01

    Unlike flapping birds and insects, bats possess membrane wings that are more similar to many gliding mammals. The vast majority of the wing is composed of a thin compliant skin membrane stretched between the limbs, hand, and body. Membrane wings are of particular interest because they may offer many advantages to micro air vehicles. One critical feature of membrane wings is that they camber passively in response to aerodynamic load, potentially allowing for simplified wing control. However, for maximum membrane wing performance, tuning of the membrane structure to aerodynamic conditions is necessary. Bats possess an array of muscles, the plagiopatagiales proprii, embedded within the wing membrane that could serve to tune membrane stiffness, or may have alternative functions. We recorded the electromyogram from the plagiopatagiales proprii muscles of Artibeus jamaicensis, the Jamaican fruit bat, in flight at two different speeds and found that these muscles were active during downstroke. For both low- and high-speed flight, muscle activity increased between late upstroke and early downstroke and decreased at late downstroke. Thus, the array of plagiopatagiales may provide a mechanism for bats to increase wing stiffness and thereby reduce passive membrane deformation. These muscles also activate in synchrony, presumably as a means to maximize force generation, because each muscle is small and, by estimation, weak. Small differences in activation timing were observed when comparing low- and high-speed flight, which may indicate that bats modulate membrane stiffness differently depending on flight speed.

  8. Fluid-structure interaction in compliant insect wings.

    PubMed

    Eberle, A L; Reinhall, P G; Daniel, T L

    2014-06-01

    Insect wings deform significantly during flight. As a result, wings act as aeroelastic structures wherein both the driving motion of the structure and the aerodynamic loading of the surrounding fluid potentially interact to modify wing shape. We explore two key issues associated with the design of compliant wings: over a range of driving frequencies and phases of pitch-heave actuation, how does wing stiffness influence (1) the lift and thrust generated and (2) the relative importance of fluid loading on the shape of the wing? In order to examine a wide range of parameters relevant to insect flight, we develop a computationally efficient, two-dimensional model that couples point vortex methods for fluid force computations with structural finite element methods to model the fluid-structure interaction of a wing in air. We vary the actuation frequency, phase of actuation, and flexural stiffness over a range that encompasses values measured for a number of insect taxa (10-90 Hz; 0-π rad; 10(-7)-10(-5) N m(2)). We show that the coefficients of lift and thrust are maximized at the first and second structural resonant frequencies of the system. We also show that even in regions of structural resonance, fluid loading never contributes more than 20% to the development of flight forces.

  9. Drag reduction through self-texturing compliant bionic materials

    PubMed Central

    Liu, Eryong; Li, Longyang; Wang, Gang; Zeng, Zhixiang; Zhao, Wenjie; Xue, Qunji

    2017-01-01

    Compliant fish skin is effectively in reducing drag, thus the design and application of compliant bionic materials may be a good choice for drag reduction. Here we consider the drag reduction of compliant bionic materials. First, ZnO and PDMS mesh modified with n-octadecane were prepared, the drag reduction of self-texturing compliant n-octadecane were studied. The results show that the mesh modified by ZnO and PDMS possess excellent lipophilic and hydrophobic, thus n-octadecane at solid, semisolid and liquid state all have good adhesion with modified mesh. The states of n-octadecane changed with temperature, thus, the surface contact angle and adhesive force all varies obviously at different state. The contact angle decreases with temperature, the adhesive force shows a lower value at semisolid state. Furthermore, the drag testing results show that the compliant n-octadecane film is more effectively in drag reduction than superhydrophobic ZnO/PDMS film, indicating that the drag reduction mechanism of n-octadecane is significantly different with superhydrophobic film. Further research shows that the water flow leads to self-texturing of semisolid state n-octadecane, which is similar with compliant fish skin. Therefore, the compliant bionic materials of semisolid state n-octadecane with regular bulge plays a major role in the drag reduction. PMID:28053309

  10. Mechanically-compliant intracortical implants reduce the neuroinflammatory response

    NASA Astrophysics Data System (ADS)

    Nguyen, Jessica K.; Park, Daniel J.; Skousen, John L.; Hess-Dunning, Allison E.; Tyler, Dustin J.; Rowan, Stuart J.; Weder, Christoph; Capadona, Jeffrey R.

    2014-10-01

    Objective. The mechanisms underlying intracortical microelectrode encapsulation and failure are not well understood. A leading hypothesis implicates the role of the mechanical mismatch between rigid implant materials and the much softer brain tissue. Previous work has established the benefits of compliant materials on reducing early neuroinflammatory events. However, recent studies established late onset of a disease-like neurodegenerative state. Approach. In this study, we implanted mechanically-adaptive materials, which are initially rigid but become compliant after implantation, to investigate the long-term chronic neuroinflammatory response to compliant intracortical microelectrodes. Main results. Three days after implantation, during the acute healing phase of the response, the tissue response to the compliant implants was statistically similar to that of chemically matched stiff implants with much higher rigidity. However, at two, eight, and sixteen weeks post-implantation in the rat cortex, the compliant implants demonstrated a significantly reduced neuroinflammatory response when compared to stiff reference materials. Chronically implanted compliant materials also exhibited a more stable blood-brain barrier than the stiff reference materials. Significance. Overall, the data show strikingly that mechanically-compliant intracortical implants can reduce the neuroinflammatory response in comparison to stiffer systems.

  11. Adaptive and controllable compliant systems with embedded actuators and sensors

    NASA Astrophysics Data System (ADS)

    Trease, Brian; Kota, Sridhar

    2007-04-01

    We present a framework for the design of a compliant system; i.e. the concurrent design of a compliant mechanism with embedded actuators and embedded sensors. Our methods simultaneously synthesize optimal structural topology and placement of actuators and sensors for maximum energy efficiency and adaptive performance, while satisfying various weight and performance constraints. The goal of this research is to lay an algorithmic framework for distributed actuation and sensing within a compliant active structure. Key features of the methodology include (1) the simultaneous optimization of the location, orientation, and size of actuators concurrent with the compliant transmission topology and (2) the concepts of controllability and observability that arise from the consideration of control, and their implementation in compliant systems design. The methods used include genetic algorithms, graph searches for connectivity, and multiple load cases implemented with linear finite element analysis. Actuators, modeled as both force generators and structural compliant elements, are included as topology variables in the optimization. Results are provided for several studies, including: (1) concurrent actuator placement and topology design for a compliant amplifier and (2) a shape-morphing aircraft wing demonstration with three controlled output nodes. Central to this method is the concept of structural orthogonality, which refers to the unique system response for each actuator it contains. Finally, the results from the controllability problem are used to motivate and describe the analogous extension to observability for sensing.

  12. Drag reduction through self-texturing compliant bionic materials

    NASA Astrophysics Data System (ADS)

    Liu, Eryong; Li, Longyang; Wang, Gang; Zeng, Zhixiang; Zhao, Wenjie; Xue, Qunji

    2017-01-01

    Compliant fish skin is effectively in reducing drag, thus the design and application of compliant bionic materials may be a good choice for drag reduction. Here we consider the drag reduction of compliant bionic materials. First, ZnO and PDMS mesh modified with n-octadecane were prepared, the drag reduction of self-texturing compliant n-octadecane were studied. The results show that the mesh modified by ZnO and PDMS possess excellent lipophilic and hydrophobic, thus n-octadecane at solid, semisolid and liquid state all have good adhesion with modified mesh. The states of n-octadecane changed with temperature, thus, the surface contact angle and adhesive force all varies obviously at different state. The contact angle decreases with temperature, the adhesive force shows a lower value at semisolid state. Furthermore, the drag testing results show that the compliant n-octadecane film is more effectively in drag reduction than superhydrophobic ZnO/PDMS film, indicating that the drag reduction mechanism of n-octadecane is significantly different with superhydrophobic film. Further research shows that the water flow leads to self-texturing of semisolid state n-octadecane, which is similar with compliant fish skin. Therefore, the compliant bionic materials of semisolid state n-octadecane with regular bulge plays a major role in the drag reduction.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Aviation Fuel Lubricity Evaluation

    DTIC Science & Technology

    1988-07-01

    cracking and subsequent fracture. The Pesco gear fuel pump in the JT-4 engine and the Chandler Evans gear fuel pump in the JT-3D engine also...TABLE 5 BOCLE ROUND-ROBIN I PARTICIPANTS Bendix Sundstrand US Navy US Air Force Chandler Evans Pratt & Whitney - East Hartford Exxon - USA Pratt...Research & Engineering X Naval Air Propulsion Center X X Esso Petroleum X Sundstrand X Lucas X Chandler Evans X Southwest Research Institute X Mountain

  18. 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...

  19. 14 CFR 33.39 - Lubrication system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  6. Investigations of lubricant rheology as applied to elastohydrodynamic lubrication

    NASA Technical Reports Server (NTRS)

    Bair, S.; Winer, W. O.

    1978-01-01

    Measurements of lubricant shear rheological behavior in the amorphous solid region and near the liquid-solid transition are reported. Elastic, plastic and viscous behavior was observed. A shear rheological model based on primary laboratory data is proposed for concentrated contact lubrication. The model is a Maxwell model modified with a limiting shear stress. Three material properties are required: low shear stress viscosity, limiting elastic shear modulus, and the limiting shear stress the material can withstand. All three are functions of temperature and pressure. In applying the model to EHD contacts the predicted response possesses the characteristics expected from several experiments reported in the literature.

  7. Materials Compatibility and Lubricants Research on CFC-refrigerant substitutes

    SciTech Connect

    Godwin, D.A.; Hourahan, G.C.; Szymurski, S.R.

    1993-04-01

    The Materials Compatibility and Lubricants Research (MCLR) program supports critical research to accelerate the introduction of CFC-refrigerant substitutes. The MCLR program addresses refrigerant and lubricant properties and materials compatibility. The primary elements of the work include data collection and dissemination, materials compatibility testing, and methods development. The work is guided by an Advisory Committee consisting of technical experts from the refrigeration and air-conditioning industry and government agencies. Under the current MCLR program the Air-Conditioning and Refrigeration Technology Institute, Inc., (ARTI) is contracting and managing multiple research projects and a data collection and dissemination effort. Detailed results from these projects are reported in technical reports prepared by each researcher.

  8. Materials Compatibility and Lubricants Research on CFC-refrigerant substitutes

    SciTech Connect

    Hourahan, G.C.; Szymurski, S.R.

    1992-10-01

    The Materials Compatibility and Lubricants Research (MCLR) program supports critical research to accelerate the introduction of CFC-refrigerant substitutes. The MCLR program addresses refrigerant and lubricant properties and materials compatibility. The primary elements of the work include data collection and dissemination, materials compatibility testing, and methods development. The work is guided by an Advisory Committee consisting of technical experts from the refrigeration and air-conditioning industry and government agencies. Under the current MCLR pregrain the Air-Conditioning and Refrigeration Technology Institute, Inc., (ARTI) is contracting and managing several research projects and a data collection and dissemination effort. Preliminary results is from these projects are reported in technical progress reports prepared by each researcher.

  9. Materials compatibility and lubricants research on CFC-refrigerant substitutes

    SciTech Connect

    Hourahan, G.C.; Szymurski, S.R.

    1993-01-01

    The materials Compatibility and Lubricants Research (MCLR) program supports critical research to accelerate the introduction of CFC-refrigerant substitutes. The MCLR program addresses refrigerant and lubricant properties and materials compatibility. The primary elements of the work include data collection and dissemination, materials compatibility testing, and methods development. The work is guided by an Advisory committee consisting of technical experts from the refrigeration and air-conditioning industry and government agencies. Under the current MCLR program the Air-Conditioning and Refrigeration Technology Institute, Inc., (ARTI) is contracting and managing multiple research projects and a data collection and dissemination effort. Preliminary results from these projects are reported in technical progress reports prepared by each researcher.

  10. Docmentation of newly developed methods to assess material compatibility in refrigeration and air-conditioning applications. Final report, 1 October 1993--31 August 1994

    SciTech Connect

    Hawley, M.

    1994-08-01

    This document summarizes the experimental methods used during the materials compatibility and lubricants research program (MCLR). The MCLR program was jointly sponsored by the U.S. Department of Energy and the air-conditioning and refrigeration industry. The individual projects were managed by the Air-Conditioning and Refrigeration Technology Institute. The projects presented in this report are: Chemical and Thermal Stability of Refrigerant/Lubricant Mixtures with Metals, Miscibility of Lubricants with Refrigerants, Compatibility of Refrigerants and Lubricants with Motor Materials, Compatibility of Refrigerants and Lubricants with Elastomers, Compatibility of Refrigerants and Lubricants with Engineering Plastics and Sealed Tube Comparisons of the Compatibility of Desiccants with Refrigerants and Lubricants.

  11. 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.

  12. Wear Debris Analysis of Grease-Lubricated Spur Gear.

    DTIC Science & Technology

    1982-12-30

    I& SUPPLEMGNTARY MOTES Gear testing performed by SKF Technology Services, SKF Industties, King of Prussia, PA. Is. KEY WORDS (CauM.. an rverm...Ifilal p s of an investigation of the wear de- bris generation characteristics of g8ease-lubricated mechanical components. SKF Technology Services...conducted at the Naval Air Engin- eering Center’s (NAVAIRENGCEN’s) Tribology Laboratory, in conjunction with SKF 1Technology Services, in a combined

  13. Compliant substrate technology for dissimilar epitaxy

    SciTech Connect

    FLORO,JERROLD A.; LEE,STEPHEN R.; FOLLSTAEDT,DAVID M.; KLEM,JOHN F.

    2000-03-01

    Strained-layer semiconductor films offer tremendous potential with regards to optoelectronic applications for high speed communications, mobile communications, sensing, and novel logic devices. It is an unfortunate reality that many of the possible film/substrate combinations that could be exploited technologically are off limits because of large differences in lattice parameters, chemical compatibilities, or thermal expansion rates. These mechanical, chemical, and thermal incompatibilities manifest themselves primarily in terms of lattice defects such as dislocations and antiphase boundaries, and in some cases through enhanced surface roughness. An additional limitation, from a production point of view, is money. Device manufacturers as a rule want the cheapest substrate possible. Freeing the heteroepitaxial world of the bonds of (near) lattice matching would vastly expand the types of working devices that could be grown. As a result, a great deal of effort has been expended finding schemes to integrate dissimilar film/substrate materials while preserving the perfection of the film layer. One such scheme receiving significant attention lately is the so-called compliant substrate approach.

  14. 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...

  15. 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...

  16. 7 CFR 2902.38 - Firearm lubricants.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Firearm lubricants. 2902.38 Section 2902.38... Items § 2902.38 Firearm lubricants. (a) Definition. Lubricants that are designed for use in firearms to reduce the friction and wear between the moving parts of a firearm, and to keep the weapon clean...

  17. 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...

  18. 7 CFR 2902.38 - Firearm lubricants.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Firearm lubricants. 2902.38 Section 2902.38... Items § 2902.38 Firearm lubricants. (a) Definition. Lubricants that are designed for use in firearms to reduce the friction and wear between the moving parts of a firearm, and to keep the weapon clean...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. 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...

  7. 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.

  8. Multifunctional lubricant additives and compositions thereof

    SciTech Connect

    Farng, L.O.; Horodysky, A.G.

    1991-03-26

    This paper discusses an antioxidant/ antiwear/extreme pressure/load carrying lubricant composition. It comprises a major proportion of an oil of lubricating viscosity or grease or other solid lubricant prepared therefrom and a minor amount of an ashless multifunctional antioxidant/antiwear/extreme pressure/load carrying additive product comprising a thiophosphate derived from a dihydrocarbyl dithiocarbamate.

  9. Compliant wall-turbulent skin-friction reduction research

    NASA Technical Reports Server (NTRS)

    Fischer, M. C.; Weinstein, L. M.; Bushnell, D. M.; Ash, R. L.

    1975-01-01

    Previous compliant-wall experiments successful in reducing skin-friction drag probably have had a (unplanned) membrane resonance at a favorable frequency, amplitude, wave shape, length, and speed. The most probable drag reduction mechanism involves a direct coupling between the fluid and the moving wall when the wall natural resonance frequencies are near the fundamental turbulent burst frequency. Local skin-friction reductions of 61% were measured with mylar/PVC plastisol compliant surfaces. These reductions were observed only at certain flow conditions, indicating that changing tunnel total temperature may have altered the substrate dynamic modulus, damping, and coupled mylar tension. Apparently, the coupled membrane/substrate must be excited in compatible narrow-band natural frequency modes. An accelerated effort is required to develop practical durable compliant surfaces optimized for maximum drag reduction. Application of compliant walls to other transportation modes appears feasible with liquid flows offering the greatest skin-friction drag reduction potential.

  10. Development and Implementation of Environmentally Compatible Solid Film Lubricants

    NASA Technical Reports Server (NTRS)

    Novak, Howard L.; Hall, Phillip B.

    1999-01-01

    Multi-body launch vehicles require the use of Solid Film Lubricants (SFLs) to allow for unrestricted relative motion between structural assemblies and components during lift-off and ascent into orbit. The Space Shuttle Solid Rocket Booster (SRB), uses a dual coat, ceramic-bonded high temperature SFL in several locations such as restraint hardware between the SRB aft skirt and the Mobile Launch Platform (MLP), the aft SRB/External Tank (ET) attach struts, and the forward skirt SRB/ET attach ball assembly. Future launch systems may require similar applications of SFLs for attachment and restraint hardware. A family of environmentally compatible non-lead/antimony bearing alternative SFLs have been developed including a compatible repair material. In addition, commercial applications for SFLs on transportation equipment, all types of lubricated fasteners, and energy related equipment allow for wide usage's of these new lubricants. The new SFLs trade named BOOSTERLUBE is a family of single layer thin film (0.001 inch maximum) coatings that are a unique mixture of non-hazardous pigments in a compatible resin system that allows for low temperature curing (450 F). Significant savings in energy and processing time as well as elimination of hazardous material usage and disposal would result from the non-toxic one-step SFL application. Compatible air-dry field repair lubricants will help eliminate disassembly of launch vehicle restraint hardware during critical time sensitive assembly operations.

  11. Development and Implementation of Environmentally Compatible Solid Film Lubricants

    NASA Technical Reports Server (NTRS)

    Novak, Howard L.; Hall, Phillip B.

    1998-01-01

    Multi-body launch vehicles require the use of Solid Film Lubricants (SFLS) to allow for unrestricted relative motion between structural assemblies and components during lift-off and ascent into orbit. The Space Shuttle Solid Rocket Booster (SRB), uses a dual coat, ceramic-bonded high temperature SFL in several locations such as restraint hardware between the SRB aft skirt and the Mobile Launch Platform (MLP), the aft SRB/External Tank (ET) attach struts, and the forward skirt SRB/ET attach ball assembly. Future launch systems may require similar applications of SFLs for attachment and restraint hardware. A family of environmentally compatible non-lead/antimony bearing alternative SFLs have been developed including a compatible repair material. In addition, commercial applications for SFLs on transportation equipment, all types of lubricated fasteners, and energy related equipment allow for wide usage's of these new lubricants. The new SFLs trade named BOOSTERLUBE is a family of single layer thin film (0.001 inch maximum) coatings that are a unique mixture of non-hazardous pigments in a compatible resin system that allows for low temperature curing (450F). Significant savings in energy and processing time as well as elimination of hazardous material usage and disposal would result from the non-toxic one-step SFL application. Compatible air-dry field repair lubricants will help eliminate disassembly of launch vehicle restraint hardware during critical time sensitive assembly operations.

  12. Development and Implementation of Environmentally Compatible Solid Film Lubricants

    NASA Technical Reports Server (NTRS)

    Novak, Howard L.; Hall, Phillip B.

    1997-01-01

    Multi-body launch vehicles require the use of Solid Film Lubricants (SFLs) to allow for unrestricted relative motion between structural assemblies and components during lift off and ascent into orbit. The Space Shuttle Solid Rocket Booster (SRB), uses a dual coat, ceramic-bonded high temperature SFL in several locations such as restraint hardware between the SRB aft skirt and the Mobile Launch Platform (MLP), the aft SRB/External Tank (ET) attach struts, and the forward skirt SRB/ET attach ball assembly. The proposed National Launch System (NLS) may require similar applications of SFLs for attachment and restraint hardware. A family of environmentally compatible nonlead/antimony bearing alternative SFLs have been developed including a compatible repair material. In addition, commercial applications for SFLs on transportation equipment, all types of lubricated fasteners, and energy related equipment allow for wide usage of these new lubricants. The new SFLs named BOOSTERLUBE is a family of single layer thin film (0.001 inch maximum) coatings that are a unique mixture of non-hazardous pigments in a compatible resin system that allows for low temperature curing (450 F). Significant savings in energy and processing time as well as elimination of hazardous material usage and disposal would result from the non-toxic onestep SFL application. Compatible air-dry field repair lubricants will help eliminate disassembly of launch vehicle restraint hardware during critical time sensitive assembly operations.

  13. High temperature aircraft turbine engine bearing and lubrication system development

    SciTech Connect

    Grant, D.H.; Chin, H.A.; Klenke, C.; Galbato, A.T.; Ragen, M.A.; Spitzer, R.F.

    1998-12-31

    Results are reported for a project sponsored by the US Air Force Wright Laboratories. The major emphasis of this project was the evaluation of bearing materials with improved corrosion resistance, high hot hardness, and high fracture toughness, intended to meet the requirements of the Integrated High Performance Turbine Engine Technologies (IHPTET) Phase 2 engine. The project included material property studies on candidate bearing materials and lubricants which formed the selection basis for subscale and full-scale bearing rig verification tests. The carburizing stainless steel alloy Pyrowear 675 demonstrated significant fatigue life, fracture toughness, and corrosion resistance improvements relative to the M50 NiL baseline bearing material. The new Skylube 2 (MCS-2482) lubricant provided significant thermal degradation improvements with respect to the Skylube 600 (PWA-524, MIL-L-87100) lubricant. Two 130 mm bore Pyrowear 675 hybrid ball bearings with silicon nitride balls were run successfully for 231 hours with Skylube 2 lubricant at temperatures consistent with IHPTET 2 requirements.

  14. SLPMC- Self Lubricating Polymer Matrix Composites

    NASA Astrophysics Data System (ADS)

    Macho, C.; Merstallinger, A.; Brodowski-Hanemann, G.; Palladino, M.; Pambaguian, L.

    2013-09-01

    The paper is surveying the current state of knowledge and results of the ESA-project "SLPMC" on a polymer composite based on PTFE. The two targets of this project are to investigate lubrication mechanisms in PTFE-based composites under tribological conditions relevant to space applications (air, nitrogen, vacuum). Secondly, to develop a new composite to fulfill future needs by space applications. Hence, in the frame of this project several new composites based on PTFE and hard fillers were defined, procured and tested on material level. Results are compared to reference materials being currently use.This paper focuses on tribological results derived by pin-on-disc tests. (Later on testing on ball bearing and plain bearing are foreseen.) The influences of parameters like load, speed, atmosphere and temperature are discussed and compared to other already known materials.

  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. 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.

  17. Quality by design compliant analytical method validation.

    PubMed

    Rozet, E; Ziemons, E; Marini, R D; Boulanger, B; Hubert, Ph

    2012-01-03

    The concept of quality by design (QbD) has recently been adopted for the development of pharmaceutical processes to ensure a predefined product quality. Focus on applying the QbD concept to analytical methods has increased as it is fully integrated within pharmaceutical processes and especially in the process control strategy. In addition, there is the need to switch from the traditional checklist implementation of method validation requirements to a method validation approach that should provide a high level of assurance of method reliability in order to adequately measure the critical quality attributes (CQAs) of the drug product. The intended purpose of analytical methods is directly related to the final decision that will be made with the results generated by these methods under study. The final aim for quantitative impurity assays is to correctly declare a substance or a product as compliant with respect to the corresponding product specifications. For content assays, the aim is similar: making the correct decision about product compliance with respect to their specification limits. It is for these reasons that the fitness of these methods should be defined, as they are key elements of the analytical target profile (ATP). Therefore, validation criteria, corresponding acceptance limits, and method validation decision approaches should be settled in accordance with the final use of these analytical procedures. This work proposes a general methodology to achieve this in order to align method validation within the QbD framework and philosophy. β-Expectation tolerance intervals are implemented to decide about the validity of analytical methods. The proposed methodology is also applied to the validation of analytical procedures dedicated to the quantification of impurities or active product ingredients (API) in drug substances or drug products, and its applicability is illustrated with two case studies.

  18. 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…

  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. 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.

  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. 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.

  3. Biobased lubricants via ruthenium catalysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  4. Compatibility of refrigerants and lubricants with elastomers. Quarterly report, 1 April 1992--30 June 1992

    SciTech Connect

    Hamed, G.R.; Seiple, R.H.

    1992-07-01

    Information contained in this reporters designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. Swell measurements have been made on approximately 50% of the proposed elastomers (94 total)in both the lubricant (7 total) and refrigerant (10 total) materials. Swell behavior in the these fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 hours and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

  5. Durability Evaluation of Selected Solid Lubricating Films

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2001-01-01

    An investigation was conducted to examine the coefficients of friction, wear rates, and durability of bonded molybdenum disulfide (MoS2), magnetron-sputtered MoS2, ion-plated silver, ion-plated lead, magnetron-sputtered diamondlike carbon (MS DLC), and plasma-assisted, chemical-vapor-deposited DLC (PACVD DLC) films in sliding contact with 6-mm-diameter AISI 440C stainless steel balls. Unidirectional ball-on-disk sliding friction experiments were conducted with a load of 5.9 N and a sliding velocity of 0.2 m/s at room temperature in three environments: ultrahigh vacuum (vacuum pressure, 7 x 10(exp -7) Pa), humid air (relative humidity, approx. 20 percent), and dry nitrogen (relative humidity, less than 1 percent). The main criteria for judging the performance of the solid lubricating films were coefficient of friction and wear rate, which had to be less than 0.3 and on the order of 10(exp -6) cu mm/N.m or less, respectively. The bonded MoS2 and magnetron-sputtered MoS2 films met the criteria in all three environments. The ion-plated lead and silver films met the criteria only in ultrahigh vacuum but failed in humid air and in dry nitrogen. The MS DLC and PACVD DLC films met the requirements in humid air and dry nitrogen but failed in ultrahigh vacuum.

  6. Evaluation of Selected Solid Lubricating Films

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2001-01-01

    An investigation was conducted to examine the friction and wear properties of bonded molybdenum disulfide (MoS2), magnetron-sputtered MoS2, ion-plated silver, ion-plated lead, magnetron-sputtered diamondlike carbon (MS DLC), and plasma-assisted, chemical-vapor-deposited DLC (PACVD DLC) films in sliding contact with 6-mm-diameter AISI 440C stainless steel balls. Unidirectional ball-on-disk sliding friction experiments were conducted with a load of 5.9 N and a sliding velocity of 0.2 m/s at room temperature in three environments: ultrahigh vacuum (vacuum pressure, 7 x 10(exp -7) Pa), humid air (relative humidity, approx. 20 percent), and dry nitrogen (relative humidity, less than 1 percent). The main criteria for judging the performance of the solid lubricating films were coefficient of friction and wear rate, which had to be less than 0.3 and on the order of 10(exp -6) cubic mm/N(dot)m or less, respectively. The bonded MoS2 and magnetron-sputtered MoS2 films met the criteria in all three environments. The ion-plated lead and silver films met the criteria only in ultrahigh vacuum but failed in humid air and in dry nitrogen. The MS DLC and PACVD DLC films met the requirements in humid air and dry nitrogen but failed in ultrahigh vacuum.

  7. Comparison Between Oil-mist and Oil-jet Lubrication of High-speed, Small-bore, Angular-contact Ball Bearings

    NASA Technical Reports Server (NTRS)

    Pinel, Stanley I.; Signer, Hans R.; Zaretsky, Erwin V.

    2001-01-01

    Parametric tests were conducted with an optimized 35-mm-bore-angular-contact ball bearing on a high-speed, high-temperature bearing tester. Results from both air-oil mist lubrication and oil-jet lubrication systems used to lubricate the bearing were compared to speeds of 2.5 x 10(exp 6) DN. The maximum obtainable speed with air-oil mist lubrication is 2.5 x 10(exp 6) DN. Lower bearing temperatures and higher power losses are obtained with oil-jet lubrication than with air-oil mist lubrication. Bearing power loss is a direct function of oil flow to the bearing and independent of oil delivery system. For a given oil-flow rate, bearing temperature and power loss increase with increases in speed. Bearing life is an inverse function of temperature, the difference in temperature between the individual bearing ring components, and the resultant elastohydrodynamic (EHD) film thicknesses. Bearing life is independent of the oil delivery system except as it affects temperature. Cage slip increased with increases in speed. Cage slip as high as 7 percent was measured and was generally higher with air-oil mist lubrication than with oil-jet lubrication.

  8. Comparison Between Oil-Mist and Oil-Jet Lubrication of High-Speed, Small-Bore, Angular-Contact Ball Bearings

    NASA Technical Reports Server (NTRS)

    Pinel, Stanley I.; Signer, Hans R.; Zaretsky, Erwin V.

    2001-01-01

    Parametric tests were conducted with an optimized 35-mm-bore-angular-contact ball bearing on a high-speed, high-temperature bearing tester. Results from both air-oil mist lubrication and oil-jet lubrication systems used to lubricate the bearing were compared to speeds of 2.5x10(exp 6) DN. The maximum obtainable speed with air-oil mist lubrication is 2.5x10(exp 6) DN. Lower bearing temperatures and higher power losses are obtained with oil-jet lubrication than with air-oil mist lubrication. Bearing power loss is a direct function of oil flow to the bearing and independent of oil delivery system. For a given oil-flow rate, bearing temperature and power loss increase with increases in speed. Bearing life is an inverse function of temperature, the difference in temperature between the individual bearing ring components, and the resultant elastohydrodynamic (EHD) film thicknesses. Bearing life is independent of the oil delivery system except as it affects temperature. Cage slip increased with increases in speed. Cage slip as high as 7% was measured and was generally higher with air-oil mist lubrication than with oil-jet lubrication.

  9. Investigations of lubricant rheology as applied to elastohydrodynamic lubrication

    NASA Technical Reports Server (NTRS)

    Kunz, R. K.; Nagaraj, H. S.; Sanborn, D. M.; Winer, W. O.

    1975-01-01

    Traction prediction in sliding elastohydrodynamic (EHD) contacts was examined along with an elastohydrodynamic lubrication simulation of the effects of load and speed on temperatures in the EHD contact. An existing shear stress theory and lubricant rheological model were studied and evaluated by applying them to traction prediction. Results obtained using measured film thickness and surface temperature data, were compared with measured traction values. The infrared technique for measuring temperatures in an EHD contact was further developed and ball surface and fluid temperatures are reported for sliding speeds of 0.35 to 5.08 m/s at 0.52 to 2.03 GN/sq m maximum pressure and surface roughnesses of .011 to .381 micrometers c.1.a. The relationship between asperity interaction, as measured by relocation surface profilimetry and high frequency temperature measurements, and the ratio of film thickness to surface roughness was also studied.

  10. Solid lubrication design methodology, phase 2

    NASA Technical Reports Server (NTRS)

    Pallini, R. A.; Wedeven, L. D.; Ragen, M. A.; Aggarwal, B. B.

    1986-01-01

    The high temperature performance of solid lubricated rolling elements was conducted with a specially designed traction (friction) test apparatus. Graphite lubricants containing three additives (silver, phosphate glass, and zinc orthophosphate) were evaluated from room temperature to 540 C. Two hard coats were also evaluated. The evaluation of these lubricants, using a burnishing method of application, shows a reasonable transfer of lubricant and wear protection for short duration testing except in the 200 C temperature range. The graphite lubricants containing silver and zinc orthophosphate additives were more effective than the phosphate glass material over the test conditions examined. Traction coefficients ranged from a low of 0.07 to a high of 0.6. By curve fitting the traction data, empirical equations for slope and maximum traction coefficient as a function of contact pressure (P), rolling speed (U), and temperature (T) can be developed for each lubricant. A solid lubricant traction model was incorporated into an advanced bearing analysis code (SHABERTH). For comparison purposes, preliminary heat generation calculations were made for both oil and solid lubricated bearing operation. A preliminary analysis indicated a significantly higher heat generation for a solid lubricated ball bearing in a deep groove configuration. An analysis of a cylindrical roller bearing configuration showed a potential for a low friction solid lubricated bearing.

  11. Gas film lubrication equations for very small clearances

    SciTech Connect

    Sobehart, J.R.; Reyna, L.G.

    1994-05-01

    In the hard disk magnetic recording technology, the slider carrying the magnetic elements is supported above the magnetic disk by a self-acting air bearing, which produces the load support. A lubricating film must support a required load with suitably small frictional energy losses and without introducing undesirable instabilities. Under submicron clearance conditions, gas film flow can not be described with continuum models since the molecular mean free path is not negligible compared with the clearance. Accurate results for the load-carrying capacity of gas films for arbitrary Knudsen number are very important since they strongly influence the design of the flying head slider and, consequently, the performance of the magnetic disk storage unit. Here we generalize the previous lubrication equations for arbitrary Knudsen number, accommodation coefficient and a small inclination of the slider relative to the magnetic disk surface.

  12. Improved boundary lubrication with formulated C-ethers

    NASA Technical Reports Server (NTRS)

    Loomis, W. R.

    1982-01-01

    A comparison of five recently developed C-ether-formulated fluids with an advanced formulated MIL-L-27502 candidate ester is described. Steady state wear and friction measurements were made with a sliding pin on disk friction apparatus. Conditions included disk temperatures up to 260 C, dry air test atmosphere, 1 kilogram load, 50 rpm disk speed, and test times to 130 minutes. Based on wear rates and coefficients of friction, three of the C-ether formulations as well as the C-ether base fluid gave better boundary lubrication than the ester fluid under all test conditions. The susceptibility of C-ethers to selective additive treatment (phosphinic esters or acids and other antiwear additives) was demonstrated when two of the formulations gave somewhat improved lubrication over the base fluid. The increased operating potential for this fluid was shown in relationship to bulk oil temperature limits for MIL-L-23699 and MIL-L-27502 type esters.

  13. Synthesis of new high performance lubricants and solid lubricants. Progress report, April 1992--March 1993

    SciTech Connect

    Lagow, R.J.

    1993-04-01

    Synthesis and testing was begun on a number of new classes of lubricants: perfluoropolyethers (branching effects), perfluoromethylene oxide ethers, chlorine-substituted fluorocarbon polyethers, fluorine-containing branched ether lubricants, glycerine- based perfluoropolyesters, perfluoro epoxy ether chains, etc.

  14. HIPPA's compliant Auditing System for Medical Imaging System.

    PubMed

    Chen, Xiaomeng; Zhang, Jianguo; Wu, Dongjing; Han, Ruoling

    2005-01-01

    As an official rule for healthcare privacy and security, Health Insurance Portability and Accountability Act (HIPAA) requires security services supporting implementation features: Access control; Audit controls; Authorization control; Data authentication; and Entity authentication. Audit controls proposed by HIPPA Security Standards are audit trails, which audit activities, to assess compliance with a secure domain's policies, to detect instances of non-compliant behavior, and to facilitate detection of improper creation, access, modification and deletion of Protected Health Information (PHI). Although current medical imaging systems generate activity logs, there is a lack of regular description to integrate these large volumes of log data into generating HIPPA compliant auditing trails. The paper outlines the design of a HIPAA's compliant auditing system for medical imaging system such as PACS and RIS and discusses the development of this security monitoring system based on the Supplement 95 of the DICOM standard: Audit Trail Messages.

  15. Performance Of Perfluoropolyalkylether Lubricant System

    NASA Technical Reports Server (NTRS)

    Paciorek, K.; Masuda, S.; Lin, Wen-Huey; Bierschenk, T.; Kawa, H.; Juhlke, T.; Lagow, R.

    1995-01-01

    Perfluoro-polyalkylethers (PFPAE) constitute class of fluids having characteristics of high thermal oxidative stability, good vicosity-temperature characteristics, good elastohydrodynamic film-forming capabilities, low volatility, and non-flammability. One unfortunate drawback PFPAE causes severe metal corrosion and fluid degradation when used in oxidizing atmosphere. Reports of interest deal with synthesis of PFPAE-type liquids and development of additive to reduce oxidizing atmosphere degradation. Properties and molecular structures reported in detail. Also lubricant performance over range of conditions.

  16. Biofluid lubrication for artificial joints

    NASA Astrophysics Data System (ADS)

    Pendleton, Alice Mae

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

  17. Solid Lubricated Rolling Element Bearings

    DTIC Science & Technology

    1979-02-15

    where L coefficient of friction Sf = film shear strength Pf = film yield pressure 0 P = substrate yield pressure 5 S becomes the...as supported by known facts. , In addition to reducing the coefficient of friction and, therefore, controlling the traction of a solid lubricated...appropriate friction coefficients . For a much closer simulation, 40 it will be necessary to make certain modifications to the program. These required

  18. The PM-200 lubrication system

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.

    1991-01-01

    Plasma sprayed composite coating of metal-bonded chromium carbide with additions of silver and thermochemically stable fluorides were previously reported to be lubricative in pin on desk bench tests from room temperature to 900 C. An early coating formulation of this type, designated as PS-200, was successfully tested as a cylinder coating in a Stirling engine at a TRRT of 760 C in a hydrogen atmosphere, and as a backup lubricant for gas bearings to 650 C. A subsequent optimization program has shown that tribological properties are further improved by increasing the solid lubricant content. The improved coating is designated as PS-212. The same powder formulation was used to make free-standing powder metallurgy (PM-212) parts by sintering or hot isostatic pressing. The process is very attractive for making parts that cannot be readily plasma sprayed such as bushings and cylinders that have small bore diameters and/or high length to diameter ratios. The properties of coatings and free-standing parts fabricated from these powders are reviewed.

  19. Elastohydrodynamic lubrication of elliptical contacts

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.

    1981-01-01

    The determination of the minimum film thickness within contact is considered for both fully flooded and starved conditions. A fully flooded conjunction is one in which the film thickness is not significantly changed when the amount of lubricant is increased. The fully flooded results presented show the influence of contact geometry on minimum film thickness as expressed by the ellipticity parameter and the dimensionless speed, load, and materials parameters. These results are applied to materials of high elastic modulus (hard EHL), such as metal, and to materials of low elastic modulus(soft EHL), such as rubber. In addition to the film thickness equations that are developed, contour plots of pressure and film thickness are given which show the essential features of elastohydrodynamically lubricated conjunctions. The crescent shaped region of minimum film thickness, with its side lobes in which the separation between the solids is a minimum, clearly emerges in the numerical solutions. In addition to the 3 presented for the fully flooded results, 15 more cases are used for hard EHL contacts and 18 cases are used for soft EHL contacts in a theoretical study of the influence of lubricant starvation on film thickness and pressure. From the starved results for both hard and soft EHL contacts, a simple and important dimensionless inlet boundary distance is specified. This inlet boundary distance defines whether a fully flooded or a starved condition exists in the contact. Contour plots of pressure and film thickness in and around the contact are shown for conditions.

  20. Lubricating oil containing VII pour depressant

    SciTech Connect

    Hart, W.P.; Mays, D.L.

    1986-08-19

    Lubricating oils for internal combustion engines typically contain a multitude of additives which function as detergents, dispersants, viscosity index improvers, pour depressants, etc. in order to improve the properties of the oil. It is found that it is particularly necessary to improve the properties exhibited by lubricating oil compositions at low temperatures. It is an object of this invention to provide a lubricating oil containing an additive which provides improved properties at low temperatures.

  1. Lubricating oil compositions containing hydroxy polyether polyamines

    SciTech Connect

    Campbell, C.B.

    1987-09-29

    This patent describes a hydroxy polyether amine or polyamine additive, and a lubricating oil composition containing a major amount of oil of lubricating viscosity and from about 0.01 to about 10 weight percent of the additive. The additives consist of certain lubricating oil soluble hydroxy polyoxyalkylene polyamines. The compositions may be either mono or polyamines, but polyamines are preferred. The additive compounds have molecular weights of from about 500 to 2000, and preferably from about 700 to 1200.

  2. Compliant tactile sensor that delivers a force vector

    NASA Technical Reports Server (NTRS)

    Torres-Jara, Eduardo (Inventor)

    2010-01-01

    Tactile Sensor. The sensor includes a compliant convex surface disposed above a sensor array, the sensor array adapted to respond to deformation of the convex surface to generate a signal related to an applied force vector. The applied force vector has three components to establish the direction and magnitude of an applied force. The compliant convex surface defines a dome with a hollow interior and has a linear relation between displacement and load including a magnet disposed substantially at the center of the dome above a sensor array that responds to magnetic field intensity.

  3. Dual-Arm Generalized Compliant Motion With Shared Control

    NASA Technical Reports Server (NTRS)

    Backes, Paul G.

    1994-01-01

    Dual-Arm Generalized Compliant Motion (DAGCM) primitive computer program implementing improved unified control scheme for two manipulator arms cooperating in task in which both grasp same object. Provides capabilities for autonomous, teleoperation, and shared control of two robot arms. Unifies cooperative dual-arm control with multi-sensor-based task control and makes complete task-control capability available to higher-level task-planning computer system via large set of input parameters used to describe desired force and position trajectories followed by manipulator arms. Some concepts discussed in "A Generalized-Compliant-Motion Primitive" (NPO-18134).

  4. Flow in Idealised Compliant Human Cystic Duct Models

    NASA Astrophysics Data System (ADS)

    Al-Atabi, M.; Chin, S. B.; Beck, S.; Luo, X. Y.

    The functions of the cystic duct and the role of its complicated geometry (in particular the valves of Heister), in the delivery of bile flow have always been a subject of speculation. This paper reports on an experimental investigation of the flow in idealised, compliant cystic duct models. The valves of Heister were idealised using eight semi-circular alternating baffles fitted inside the compliant tubes. These tubes were arranged in configurations representing the anatomical configurations of real cystic ducts. Models both with and without baffles were tested for comparison. The results show that the valves of Heister seem to play a role in facilitating both the filling and emptying of the gallbladder.

  5. Pyrolytic Carbon As A Lubricant In Hot Ceramic Bearings

    NASA Technical Reports Server (NTRS)

    Lauer, J. L.; Davis, L. C.

    1996-01-01

    Pyrolytic carbon proves useful as solid lubricant in ceramic bearings in advanced gas-turbine engines, where high temperatures destroy liquid lubricants. Ethylene gas made to flow past bearings and pyrolized to replenish carbon lubricant particles.

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

    SciTech Connect

    Erdemir, A.

    1995-07-11

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

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

    SciTech Connect

    Erdemir, Ali

    1995-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Suzuki, Hisashi; Fukuta, Mitsuhiro; Yanagisawa, Tadashi

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

  9. LUBRICATING AND SIZING AGENT FOR GLASS FIBER,

    DTIC Science & Technology

    GLASS TEXTILES, SURFACE PROPERTIES), (*LUBRICANTS, GLASS TEXTILES), FIBERS , POLYVINYL ALCOHOL, STEARATES, CHROMIUM COMPOUNDS, ALUMINUM COMPOUNDS, MIXTURES, LACTATES, TITANIUM COMPOUNDS, MECHANICAL PROPERTIES, USSR

  10. Lubrication system with tolerance for reduced gravity

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  11. Testing and Lubrication for Single Race Bearings

    SciTech Connect

    Steinhoff, R.G.

    1998-03-04

    Three ES and H-compatible lubricants (Environment, Safety and Health) for single race bearing applications and one hybrid-material single race bearings were evaluated and compared against single race bearings with trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon), which is an ozone-depleting solvent. Vydax has been used as a bearing lubricant in stronglink mechanisms since 1974. Hybrid bearings with silicon nitride balls and molded glass-nylon-Teflon retainers, bearings lubricated with titanium carbide (TiC) on the balls, bearings lubricated with sputtered MoS{sub 2} on races and retainers, and bearings lubricated with electrophoretically deposited MoS{sub 2} were evaluated. The bearings were maintained in a preloaded state in bearing cartridges during cycling and vibration tests. Bearings with electrophoretically deposited MoS{sub 2} performed as well as bearings lubricated with Vydax and were the best performing candidate. All candidates were suitable for low preload applications. Bearings with TiC coated balls and bearings lubricated with sputtered MoS{sub 2} on the races and retainers performed well at high preloads, though not as well as bearings lubricated with electrophoretic deposition of MoS{sub 2}. Bearings with silicon nitride balls were not suitable for high preload applications.

  12. Lubrication System with Tolerance for Reduced Gravity

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  13. Solid Lubrication Fundamentals and Applications. Chapter 2

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1998-01-01

    This chapter describes powerful analytical techniques capable of sampling tribological surfaces and solid-film lubricants. Some of these techniques may also be used to determine the locus of failure in a bonded structure or coated substrate; such information is important when seeking improved adhesion between a solid-film lubricant and a substrate and when seeking improved performance and long life expectancy of solid lubricants. Many examples are given here and through-out the book on the nature and character of solid surfaces and their significance in lubrication, friction, and wear. The analytical techniques used include the late spectroscopic methods.

  14. Energy star compliant voice over internet protocol (VoIP) telecommunications network including energy star compliant VoIP devices

    DOEpatents

    Kouchri, Farrokh Mohammadzadeh

    2012-11-06

    A Voice over Internet Protocol (VoIP) communications system, a method of managing a communications network in such a system and a program product therefore. The system/network includes an ENERGY STAR (E-star) aware softswitch and E-star compliant communications devices at system endpoints. The E-star aware softswitch allows E-star compliant communications devices to enter and remain in power saving mode. The E-star aware softswitch spools messages and forwards only selected messages (e.g., calls) to the devices in power saving mode. When the E-star compliant communications devices exit power saving mode, the E-star aware softswitch forwards spooled messages.

  15. Influence of liquid lubricant properties on their performance

    NASA Technical Reports Server (NTRS)

    Wedeven, V.

    1972-01-01

    The influence of lubricant properties on performance is considered in connection with various mechanisms of lubrication. The effects of temperature and pressure on viscosity, which is important in hydrodynamic and elastohydrodynamic lubrication, is presented using a correlation postulated by Roelands. Under elastohydrodynamic conditions it is important to distinguish between the influence of lubricant properties within the inlet region and the Hertz region since each performs different functions. The role of lubricant transport properties such as surface tension is considered in connection with lubricant starvation. Since the lubrication of practical surfaces usually involves boundary as well as hydrodynamic mechanisms, both the chemical and physical properties significantly influence the lubricant's performance.

  16. Self-lubricating polymer composites and polymer transfer film lubrication for space applications

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    1990-01-01

    The use of self-lubricating polymers and polymer composites in space is somewhat limited today. In general, they are only used when other methods are inadequate. There is potential, however, for these materials to make a significant impact on future space missions if properly utilized. Some of the different polymers and fillers used to make self-lubricating composites are surveyed. The mechanisms of composite lubrication and wear, the theory behind transfer film lubricating mechanisms, and some factors which affect polymer composite wear and transfer are examined. In addition, some of the current space tribology application areas for self-lubricating polymer composites and polymer transfer are mentioned.

  17. High-Temperature Solid Lubricants Developed by NASA Lewis Offer Virtually "Unlimited Life" for Oil-Free Turbomachinery

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Valco, Mark J.

    1999-01-01

    The NASA Lewis Research Center is capitalizing on breakthroughs in foil air bearing performance, tribological coatings, and computer analyses to formulate the Oil-free Turbomachinery Program. The program s long-term goal is to develop an innovative, yet practical, oil-free aeropropulsion gas turbine engine that floats on advanced air bearings. This type of engine would operate at higher speeds and temperatures with lower weight and friction than conventional oil-lubricated engines. During startup and shutdown, solid lubricant coatings are required to prevent wear in such engines before the self-generating air-lubrication film develops. NASA s Tribology Branch has created PS304, a chrome-oxide-based plasma spray coating specifically tailored for shafts run against foil bearings. PS304 contains silver and barium fluoride/calcium fluoride eutectic (BaF2/CaF2) lubricant additives that, together, provide lubrication from cold start temperatures to over 650 C, the maximum use temperature for foil bearings. Recent lab tests show that bearings lubricated with PS304 survive over 100 000 start-stop cycles without experiencing any degradation in performance due to wear. The accompanying photograph shows a test bearing after it was run at 650 C. The rubbing process created a "polished" surface that enhances bearing load capacity.

  18. Steady-state wear and friction in boundary lubrication studies

    NASA Technical Reports Server (NTRS)

    Loomis, W. R.; Jones, W. R., Jr.

    1980-01-01

    A friction and wear study was made at 20 C to obtain improved reproducibility and reliability in boundary lubrication testing. Ester-base and C-ether-base fluids were used to lubricate a pure iron rider in sliding contact with a rotating M-50 steel disk in a friction and wear apparatus. Conditions included loads of 1/2 and 1 kg and sliding velocities of 3.6 to 18.2 m/min in a dry air atmosphere and stepwise time intervals from 1 to 250 min for wear measurements. The wear rate results were compared with those from previous studies where a single 25 min test period was used. Satisfactory test conditions for studying friction and wear in boundary lubrication for this apparatus were found to be 1 kg load; sliding velocities of 7.1 to 9.1 m/min (50 rpm disk speed); and use of a time stepwise test procedure. Highly reproducible steady-state wear rates and steady-state friction coefficients were determined under boundary conditions. Wear rates and coefficients of friction were constant following initially high values during run-in periods.

  19. Hydraulic Capacity of an ADA Compliant Street Drain Grate

    SciTech Connect

    Lottes, Steven A.; Bojanowski, Cezary

    2015-09-01

    Resurfacing of urban roads with concurrent repairs and replacement of sections of curb and sidewalk may require pedestrian ramps that are compliant with the American Disabilities Act (ADA), and when street drains are in close proximity to the walkway, ADA compliant street grates may also be required. The Minnesota Department of Transportation ADA Operations Unit identified a foundry with an available grate that meets ADA requirements. Argonne National Laboratory’s Transportation Research and Analysis Computing Center used full scale three dimensional computational fluid dynamics to determine the performance of the ADA compliant grate and compared it to that of a standard vane grate. Analysis of a parametric set of cases was carried out, including variation in longitudinal, gutter, and cross street slopes and the water spread from the curb. The performance of the grates was characterized by the fraction of the total volume flow approaching the grate from the upstream that was captured by the grate and diverted into the catch basin. The fraction of the total flow entering over the grate from the side and the fraction of flow directly over a grate diverted into the catch basin were also quantities of interest that aid in understanding the differences in performance of the grates. The ADA compliant grate performance lagged that of the vane grate, increasingly so as upstream Reynolds number increased. The major factor leading to the performance difference between the two grates was the fraction of flow directly over the grates that is captured by the grates.

  20. VCM Process Design: An ABET 2000 Fully Compliant Project

    ERIC Educational Resources Information Center

    Benyahia, Farid

    2005-01-01

    A long experience in undergraduate vinyl chloride monomer (VCM) process design projects is shared in this paper. The VCM process design is shown to be fully compliant with ABET 2000 criteria by virtue of its abundance in chemical engineering principles, integration of interpersonal and interdisciplinary skills in design, safety, economics, and…

  1. DNA origami compliant nanostructures with tunable mechanical properties.

    PubMed

    Zhou, Lifeng; Marras, Alexander E; Su, Hai-Jun; Castro, Carlos E

    2014-01-28

    DNA origami enables fabrication of precise nanostructures by programming the self-assembly of DNA. While this approach has been used to make a variety of complex 2D and 3D objects, the mechanical functionality of these structures is limited due to their rigid nature. We explore the fabrication of deformable, or compliant, objects to establish a framework for mechanically functional nanostructures. This compliant design approach is used in macroscopic engineering to make devices including sensors, actuators, and robots. We build compliant nanostructures by utilizing the entropic elasticity of single-stranded DNA (ssDNA) to locally bend bundles of double-stranded DNA into bent geometries whose curvature and mechanical properties can be tuned by controlling the length of ssDNA strands. We demonstrate an ability to achieve a wide range of geometries by adjusting a few strands in the nanostructure design. We further developed a mechanical model to predict both geometry and mechanical properties of our compliant nanostructures that agrees well with experiments. Our results provide a basis for the design of mechanically functional DNA origami devices and materials.

  2. Piezoelectric compliant mechanism energy harvesters under large base excitations

    NASA Astrophysics Data System (ADS)

    Ma, Xiaokun; Trolier-McKinstry, Susan; Rahn, Christopher D.

    2016-09-01

    A piezoelectric compliant mechanism (PCM) energy harvester is designed, modeled, and analyzed that consists of a polyvinylidene diflouoride, PVDF unimorph clamped at its base and attached to a compliant mechanism at its tip. The compliant hinge stiffness is carefully tuned to approach a low frequency first mode with an efficient (nearly quadratic) shape that provides a uniform strain distribution. A nonlinear model of the PCM energy harvester under large base excitation is derived to determine the maximum power that can be generated by the device. Experiments with a fabricated PCM energy harvester prototype show that the compliant mechanism introduces a stiffening effect and a much wider bandwidth than a benchmark proof mass cantilever design. The PCM bridge structure self-limits the displacement and maximum strain at large excitations compared with the proof mass cantilever, improving the device robustness. The PCM outperforms the cantilever in both average power and power-strain sensitivity at high accelerations due to the PCM axial stretching effect and its more uniform strain distribution.

  3. Prediction of compliant wall drag reduction, part 2

    NASA Technical Reports Server (NTRS)

    Orszag, S. A.

    1979-01-01

    A numerical model of turbulent boundary layer flows over compliant walls was investigated. The model is based on Burton's observation that outer flow structures in turbulent boundary layers produce large scale pressure fluctuations near the wall. The results of calculations indicate that certain small wavelength wall motions can have a significant effect upon the stability of turbulent boundary layers.

  4. Dry compliant seal for phosphoric acid fuel cell

    DOEpatents

    Granata, Jr., Samuel J.; Woodle, Boyd M.

    1990-01-01

    A dry compliant overlapping seal for a phosphoric acid fuel cell preformed f non-compliant Teflon to make an anode seal frame that encircles an anode assembly, a cathode seal frame that encircles a cathode assembly and a compliant seal frame made of expanded Teflon, generally encircling a matrix assembly. Each frame has a thickness selected to accommodate various tolerances of the fuel cell elements and are either bonded to one of the other frames or to a bipolar or end plate. One of the non-compliant frames is wider than the other frames forming an overlap of the matrix over the wider seal frame, which cooperates with electrolyte permeating the matrix to form a wet seal within the fuel cell that prevents process gases from intermixing at the periphery of the fuel cell and a dry seal surrounding the cell to keep electrolyte from the periphery thereof. The frames may be made in one piece, in L-shaped portions or in strips and have an outer perimeter which registers with the outer perimeter of bipolar or end plates to form surfaces upon which flanges of pan shaped, gas manifolds can be sealed.

  5. Compliant displacement-multiplying apparatus for microelectromechanical systems

    DOEpatents

    Kota, Sridhar; Rodgers, M. Steven; Hetrick, Joel A.

    2001-01-01

    A pivotless compliant structure is disclosed that can be used to increase the geometric advantage or mechanical advantage of a microelectromechanical (MEM) actuator such as an electrostatic comb actuator, a capacitive-plate electrostatic actuator, or a thermal actuator. The compliant structure, based on a combination of interconnected flexible beams and cross-beams formed of one or more layers of polysilicon or silicon nitride, can provide a geometric advantage of from about 5:1 to about 60:1 to multiply a 0.25-3 .mu.m displacement provided by a short-stroke actuator so that such an actuator can be used to generate a displacement stroke of about 10-34 .mu.m to operate a ratchet-driven MEM device or a microengine. The compliant structure has less play than conventional displacement-multiplying devices based on lever arms and pivoting joints, and is expected to be more reliable than such devices. The compliant structure and an associated electrostatic or thermal actuator can be formed on a common substrate (e.g. silicon) using surface micromachining.

  6. Application of the active camber morphing concept based on compliant structures to a regional aircraft

    NASA Astrophysics Data System (ADS)

    De Gaspari, Alessandro; Ricci, Sergio

    2014-04-01

    The present work addresses the optimal design of a morphing mechanism based on compliant structures used to implement the active camber morphing concept. The subject of the work is part of the FP7-NOVEMOR project (Novel Air Vehicle Configurations: From Fluttering Wings to Morphing Flight) which is one of the many projects from the seventh European Framework Programme. The implementation of active camber concept is based on the use of conformable morphing control surfaces. Aiming at the optimal design of such as morphing devices, two dedicated tools called PHORMA and SPHERA, respectively, are introduced. The definition of the optimal shape taking into account both aerodynamic and structural constraints is done by PHORMA. Then SPHERA, based on the load path approach codified by coupling a non linear beam solver to a genetic multi- objective optimizer, is adopted to generate the optimal internal structure able to produce, when loaded, the target optimal shape. The paper is mainly focused on the optimal design of the compliant structures starting from the optimal shape already available for a Reference Aircraft (RA) developed inside NOVEMOR project and representative of a typical regional jet capable to carry 113 PAX in a single economic class.

  7. LUBRICATED TRANSPORT OF VISCOUS FLUIDS

    SciTech Connect

    JOSEPH, DANIEL D

    2004-06-21

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

  8. Fuel detergent compositions containing lubricating oil

    SciTech Connect

    Bagnetto, L.J.

    1982-04-20

    A motor fuel additive composition comprising a fuel detergent composition and a lubricating oil is disclosed. In preferred embodiments aminosuccinimide and amide-sulfonate fuel additive compositions are combined with lubricating oil in a fuel composition which exhibits reduced formation of engine deposits, particularly under additive-overdose conditions.

  9. Positive commandable oiler for satellite bearing lubrication

    NASA Technical Reports Server (NTRS)

    James, G. E.

    1977-01-01

    The results of a feasibility study showed that on-orbit commandable lubrication of ball bearings can be accomplished by direct oil application to the moving ball surfaces. Test results for the lubricant applicator portion of the system are presented, in conjunction with a design approach for the reservoir and metering components.

  10. Progress in environmentally friendly lubricant development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Environmentally friendly lubricants comprise ingredients derived from natural raw materials such as those harvested from farms, forests, etc. There is a great deal of interest in such lubricants because of their potential economic, environmental, health, and safety benefits over petroleum-based prod...

  11. Method of removing hydroperoxides from lubricating oils

    SciTech Connect

    Shaub, H.; Brownawell, D.W.; DiBenedetto, A.

    1991-03-05

    This patent describes a method of decomposing hydroperoxides present in a lubricating oil. It comprises: contacting the lubricating oil with a heterogenous hydroperoxide decomposer for a period of time sufficient to cause a reduction in the amount of hydroperoxides present in the oil, the hydroperoxide decomposer being immobilized when contacting the oil so as not to pass into the oil.

  12. 30 CFR 57.14204 - Machinery lubrication.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  13. 30 CFR 56.14204 - Machinery lubrication.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  14. 49 CFR 396.5 - Lubrication.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  15. A cartilage-inspired lubrication system.

    PubMed

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

    2014-01-14

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

  16. Lubricating Holes for Corroded Nuts and Bolts

    NASA Technical Reports Server (NTRS)

    Penn, B. G.; Clemons, J. M.; Ledbetter, Frank E., III

    1986-01-01

    Corroded fasteners taken apart more easily. Lubricating holes bored to thread from three of flats. Holes facilitate application of penetrating oil to help loosen nut when rusted onto bolt. Holes make it possible to apply lubricants and rust removers directly to more of thread than otherwise reachable.

  17. Glass molding process with mold lubrication

    DOEpatents

    Davey, Richard G.

    1978-06-27

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

  18. Ionic liquids as lubricant additives: A review

    DOE PAGES

    Zhou, Yan; Qu, Jun

    2016-12-28

    In pursuit of energy efficiency and durability throughout human history, advances in lubricants have always played important roles. Ionic liquids (ILs) are room-temperature molten salts that possess unique physicochemical properties and have shown great potential in many applications with lubrication as one of the latest. While earlier work (2001–2011) primarily explored the feasibility of using ILs as neat or base lubricants, using ILs as lubricant additives has become the new focal research topic since the breakthrough in ILs’ miscibility in nonpolar hydrocarbon oils in early 2012. This work reviews the recent advances in developing ILs as additives for lubrication withmore » an attempt to correlate among the cationic and anionic structures, oil-solubility, and other relevant physicochemical properties, and lubricating behavior. Effects of the concentration of ILs in lubricants and the compatibility between ILs and other additives in the lubricant formulation on the tribological performance are described followed by a discussion of wear protection mechanism based on tribofilm characterization. As a result, future research directions are suggested at the end.« less

  19. Ionic liquids as lubricant additives: A review

    SciTech Connect

    Zhou, Yan; Qu, Jun

    2016-12-28

    In pursuit of energy efficiency and durability throughout human history, advances in lubricants have always played important roles. Ionic liquids (ILs) are room-temperature molten salts that possess unique physicochemical properties and have shown great potential in many applications with lubrication as one of the latest. While earlier work (2001–2011) primarily explored the feasibility of using ILs as neat or base lubricants, using ILs as lubricant additives has become the new focal research topic since the breakthrough in ILs’ miscibility in nonpolar hydrocarbon oils in early 2012. This work reviews the recent advances in developing ILs as additives for lubrication with an attempt to correlate among the cationic and anionic structures, oil-solubility, and other relevant physicochemical properties, and lubricating behavior. Effects of the concentration of ILs in lubricants and the compatibility between ILs and other additives in the lubricant formulation on the tribological performance are described followed by a discussion of wear protection mechanism based on tribofilm characterization. As a result, future research directions are suggested at the end.

  20. Biobased, environmentally friendly lubricants for processing plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  1. Pressure-viscosity coefficient of biobased lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  2. Lubricating oil compositions containing modified succinimides

    SciTech Connect

    Wollenberg, R.H.

    1987-05-05

    A lubricating oil composition is described comprising an oil of lubricating viscosity and from 0.2 to 10 percent by weight of a product produced by the process. A temperature is contacted sufficient to cause reaction. A polyamino alkenyl or alkyl succinimide contains at least one primary or secondary amine and a compound. A formula is given.

  3. A High Temperature Vapor Phase Lubrication Study Utilizing a Thioether Liquid Lubricant

    NASA Technical Reports Server (NTRS)

    Morales, Wilfredo; Graham, E. Earl; Galvin, Thomas

    1997-01-01

    Much of the experimental work on vapor phase lubrication has employed certain organo phosphorous compounds as the vapor phase lubricant. Graham and Klaus, for instance, used tricresyl phosphate (TCP) and tributyl phosphate to vapor phase lubricate a four-ball wear tester using M50 steel balls at 370 C. Makki and Graham were able to vapor phase lubricate a reciprocating pin on plate tribometer using 1018 steel at 280 C with TCP vapor. Although a few organo phosphorous compounds, such as TCP, have been successfully used as vapor phase lubricants in many laboratory experiments, many problems remain unsolved. Two areas of concern relate to the 'durability' of phosphate deposited films and to the ability of the lubricating system to "self-recover" when vapor phase lubricated with an organo phosphorous compound. Durability refers to the ability of the deposited film to provide effective lubrication, for a period of time, after the vapor flow to the lubricating surfaces has been interrupted. Vapor phase lubrication tests, conducted at Cleveland State University with their high temperature tribometer, revealed that when TCP vapor flow to the lubricating surfaces was interrupted the frictional coefficient of the system rapidly increased from a value less than 0.1 to a value of 0.3 which was selected as our failure point. Self-recovery means the ability of the vapor phase lubricant to reduce the frictional coefficient of the lubricating system back down to value less than 0.1 after startup of the interrupted vapor flow. Lubrication tests conducted at Cleveland State University revealed that the high temperature tribometer could not self-recover after startup of the interrupted TCP vapor flow.

  4. Bearing, gearing, and lubrication technology

    NASA Technical Reports Server (NTRS)

    Anderson, W. J.

    1978-01-01

    Results of selected NASA research programs on rolling-element and fluid-film bearings, gears, and elastohydrodynamic lubrication are reported. Advances in rolling-element bearing material technology, which have resulted in a significant improvement in fatigue life, and which make possible new applications for rolling bearings, are discussed. Research on whirl-resistant, fluid-film bearings, suitable for very high-speed applications, is discussed. An improved method for predicting gear pitting life is reported. An improved formula for calculating the thickness of elastohydrodynamic films (the existence of which help to define the operating regime of concentrated contact mechanisms such as bearings, gears, and cams) is described.

  5. Stiffness modeling of compliant parallel mechanisms and applications in the performance analysis of a decoupled parallel compliant stage

    NASA Astrophysics Data System (ADS)

    Jiang, Yao; Li, Tie-Min; Wang, Li-Ping

    2015-09-01

    This paper investigates the stiffness modeling of compliant parallel mechanism (CPM) based on the matrix method. First, the general compliance matrix of a serial flexure chain is derived. The stiffness modeling of CPMs is next discussed in detail, considering the relative positions of the applied load and the selected displacement output point. The derived stiffness models have simple and explicit forms, and the input, output, and coupling stiffness matrices of the CPM can easily be obtained. The proposed analytical model is applied to the stiffness modeling and performance analysis of an XY parallel compliant stage with input and output decoupling characteristics. Then, the key geometrical parameters of the stage are optimized to obtain the minimum input decoupling degree. Finally, a prototype of the compliant stage is developed and its input axial stiffness, coupling characteristics, positioning resolution, and circular contouring performance are tested. The results demonstrate the excellent performance of the compliant stage and verify the effectiveness of the proposed theoretical model. The general stiffness models provided in this paper will be helpful for performance analysis, especially in determining coupling characteristics, and the structure optimization of the CPM.

  6. Wear Debris Analysis of Grease Lubricated Ball Bearings.

    DTIC Science & Technology

    1982-04-12

    fluid and debris were placed in a glass bottle and sealed with a plastic cap using a teflon sealing disk. The grease and cleaning fluid were...manner. 1. Ten 3m-diameter glass beads were placed in a 1/2 ounce bottle . The use of these glass beads aided the agitation process of the grease...AD-A19’ 470 NAVAL AIR ENGINEERING CENTER LAKEHURST NJ SUPPORT EGU -ETC F/B 11/9 WEAR DEBRIS ANALYSIS OF GREASE LUBRICATED BALL BEARINGS(U

  7. Vermiculite as a component of thread lubricants

    SciTech Connect

    Kaminskii, S.E.; Shibryaev, S.B.; Lyubinin, I.A.; Nemets, V.L.

    1994-09-01

    Thread lubricants are used in threaded joints of piping and pump/compressor equipment of drilling units in order to protect the threads against wear and galling during the operations of making up and breaking the joints; the lubricants also serve as a seal against the pressure of liquid and gaseous media. Commercial thread lubricants contain fillers to provide the required level of antigalling, antiwear, and sealing properties. Powders of lead, copper, zinc, and their compounds are widely used as fillers; other materials that are used include finely dispersed molybdenum disulfide and polytetrafluoroethylene. The concentrations of these components in commercial thread lubricants may be as high as 60-70%,{sup *} so that the lubricants are quite expensive. Lead compounds have the further disadvantages of toxicity, requiring special protective measures in the production, storage, and application of the lubricants - i.e., these materials are ecologically hazardous. Production of specialized thread lubricants is limited by shortages of fillers, and hence general-purpose greases are almost universally used in threaded joints - greases that are inferior to thread lubricants in their set of tribotechnical properties. The end results are premature wear and leakage of the joints, losses of oil and gas, and environmental pollution. In this connection, it is of interest to use layered minerals, in particular vermiculite, in thread lubricant formulations. Heat-treated and milled vermiculite, which has a structure similar to graphite, is resistant to oxidation and to attack by corrosive media; it has a high upper temperature limit of serviceability as a lubricant, and it is readily available and inexpensive. Major reserves of vermiculite have been explored in the Kola Peninsula (Kovdor deposit), in the Urals (Potaninsk and Buldymsk deposits) and in Siberia (Sludyanka deposit).

  8. Lubrication and failure mechanisms of molybdenum disulfide films. 1: Effect of atmosphere

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.

    1978-01-01

    Friction, wear, and wear lives of rubbed molybdenum disulfide (MoS2 films applied to sanded 440C HT steel surfaces were evaluated in moist air, dry air, and dry argon. Optical microscope observations were made as a function of sliding distance to determine the effect of moisture and oxygen on the lubricating and failure mechanisms of MoS2 films. In general, the lubrication process consisted of the formation of a thin, metallic colored, coalesced film of MoS2 that flowed between the surfaces in relative motion. In air, failure was due to the transformation of the metallic colored, coalesced films to a black, powdery material. Water in the air appeared to accelerate the transformation rate. In argon, no transformation of MoS2 was observed with the microscope, but cracking and spalling of the coalesced film occurred and resulted in the gradual depletion of the film.

  9. Self-Lubricity of WSex Nanocomposite Coatings.

    PubMed

    Domínguez-Meister, S; Conte, M; Igartua, A; Rojas, T C; Sánchez-López, J C

    2015-04-22

    Transition metal chalcogenides with lamellar structure are known for their use in tribological applications although limited to vacuum due to their easy degradation in the presence of oxygen and/or moisture. Here we present a tailored WSex coating with low friction (0.07) and low wear rates (3×10(-7) mm3 Nm(-1)) even in ambient air. To understand the low friction behavior and lower chemical reactivity a tribological study is carried out in a high-vacuum tribometer under variable pressure (atmospheric pressure to 1×10(-8) mbar). A detailed investigation of the film nanostructure and composition by advanced transmission electron microscopy techniques with nanoscale resolution determined that the topmost layer is formed by nanocrystals of WSe2 embedded in an amorphous matrix richer in W, a-W(Se). After the friction test, an increased crystalline order and orientation of WSe2 lamellas along the sliding direction were observed in the interfacial region. On the basis of high angle annular dark field, scanning transmission electron microscopy, and energy dispersive X-ray analysis, the release of W atoms from the interstitial basal planes of the a-W(Se) phase is proposed. These W atoms reaching the surface, play a sacrificial role preventing the lubricant WSe2 phase from oxidation. The increase of the WSe2 crystalline order and the buffer effect of W capturing oxygen atoms would explain the enhanced chemical and tribological response of this designed nanocomposite material.

  10. Rock drill bit lubrication system

    SciTech Connect

    Johansson, C.

    1980-07-08

    A drill bit is described that includes a body part, a first chamber in said body part for containing a fluid lubricat under pressure higher than atmosphere during operation of the drill bit, at least one bit segment extending from said body part, a generally conical cutting element mounted on said bit segment and freely rotatable thereon thus forming a cutting element assembly, the improvement in combination therewith, wherein: said bit segment iclujdes an annular part having inner and outer circumferential bearing surfaces, said conical cutting element has corresponding bearing surfaces adjacent those of said annular part thereby forming two pairs of bearing surfaces defining first and second raceways, the second raceway being radially outward of the first raceway, said second raceway further includes a plurlaity of ball bearing elements distributed therein, this second raceway and ball bearing elements forming a locking bearing for retaining said conical cutting element coupled to said annular part of said bit segment, said cutting element assembly further comprising a plurality of rolling bearing elements distributed in said second raceway forming an inner bearing, and lubrication mens for lubricating said raceways and bearing elements therein.

  11. Solvent extraction of lubricating oils

    SciTech Connect

    Sequeira, A. Jr.

    1991-08-13

    This patent describes improvement in a process for solvent refining a hydrocarbon based lubricating oil stock containing aromatics and non-aromatics components with an extraction solvent wherein the lubricating oil stock is contacted with the extraction solvent in a first extraction zone at a first extraction temperature in the range of 100{degrees} F to 250{degrees} F and a solvent to oil dosage in the range of 75 to 500 vol % forming an aromatics-rich primary extract and an aromatics-lean primary raffinate of high viscosity index of at least 85. The improvement comprises: withdrawing and cooling the primary extract to a temperature 10{degrees} F to 120{degrees} F below the extraction temperature and admixing with 0.0 vol % to 10 vol % anti-solvent thereby forming a secondary extract and a secondary raffinate, passing the secondary raffinate to a second extraction zone wherein the secondary raffinate is contacted with the extraction solvent at a second extraction temperature in the range of 100{degrees} F to 250{degrees} F and solvent to oil dosage in the range of 75 to 500 vol %, to form an aromatics-lean tertiary raffinate phase of viscosity index 65 or greater.

  12. Compliant alkali silicate sealing glass for solid oxide fuel cell applications: thermal cycle stability and chemical compatibility

    SciTech Connect

    Chou, Y. S.; Thomsen, Edwin C.; Williams, Riley T.; Choi, Jung-Pyung; Canfield, Nathan L.; Bonnett, Jeff F.; Stevenson, Jeffry W.; Shyam, Amit; Lara-Curzio, E.

    2011-03-01

    An alkali silicate glass (SCN-1) is currently being evaluated as a candidate sealing glass for solid oxide fuel (SOFC) applications. The glass containing ~17 mole% alkalis (K2O and Na2O) remains vitreous and compliant during SOFC operation, unlike conventional SOFC sealing glasses, which experience substantial devitrification after the sealing process. The non-crystallizing compliant sealing glass has lower glass transition and softening temperatures since the microstructure remains glassy without significant crystallite formation, and hence can relieve or reduce residual stresses and also has the potential for crack healing. Sealing approaches based on compliant glass will also need to satisfy all the mechanical, thermal, chemical, physical, and electrical requirements for SOFC applications, not only in bulk properties but also at sealing interfaces. In this first of a series of papers we will report the thermal cycle stability of the glass when sealed between two SOFC components, i.e., a NiO/YSZ anode supported YSZ bilayer and a coated ferritic stainless steel interconnect material. High temperature leak rates were monitored versus thermal cycles between 700-850oC using back pressures ranging from 0.2 psi to 1.0 psi. Isothermal stability was also evaluated in a dual environment consisting of flowing dilute H2 fuel versus ambient air. In addition, chemical compatibility at the alumina and YSZ interfaces was examined with scanning electron microscopy and energy dispersive spectroscopy. The results shed new light on the topic of SOFC glass seal development.

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

    PubMed

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

    2016-10-01

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

  14. A tribological study of UHMWPE acetabular cups and polyurethane compliant layer acetabular cups.

    PubMed

    Smith, S L; Ash, H E; Unsworth, A

    2000-01-01

    A novel design of polyurethane compliant layer acetabular cup has been developed through a series of friction, creep and wear tests. Friction tests were initially conducted on ABG standard form, polyurethane acetabular cups and an ABG standard form, UHMWPE acetabular cup for comparison. The polyurethane cups showed lower friction than the UHMWPE cup with maximum friction factors between 0. 008 and 0.02 compared with 0.035 for the UHMWPE cup. This indicated that, in the polyurethane cups, more of the load across the joint was carried by the fluid entrapped in the joint space rather than with asperity contact, compared with the UHMWPE cup. The inherent compliance of the polyurethane is used to promote elasto-hydrodynamic lubrication. However, this compliance raised concerns over excessive creep, which may in turn adversely affect tribological performance. Therefore, creep tests were undertaken on the ABG standard form, polyurethane acetabular cups followed by further friction tests. Small amounts of creep occurred in the polyurethane cups at ambient temperature, which reduced the friction slightly (maximum friction factors of 0.009) due to increased conformity between the head and the cup. However, at 37 degrees C, greater creep occurred causing pinching of the femoral head by the acetabular cup resulting in lubricant starvation and higher friction (maximum friction factors of 0.035). The design of the polyurethane cups was subsequently modified to incorporate a flared rim to eliminate the possibility of fluid starvation through pinching. Creep in polyurethane acetabular cups is also affected by the method of fixation of the cups, due to the conformity with and the stiffness of the cup backing. Hence, a one-million-cycle wear test was performed on five ABG flared form, polyurethane acetabular cups on the Mk. I Durham Hip Joint Wear Simulator to evaluate the best method of fixation for the polyurethane cups. The smallest amount of penetration, due to creep and wear

  15. 7 CFR 3201.73 - Slide way lubricants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Slide way lubricants. 3201.73 Section 3201.73... Designated Items § 3201.73 Slide way lubricants. (a) Definition. Products used to provide lubrication and... this part, will give a procurement preference for qualifying biobased slide way lubricants. By...

  16. 7 CFR 3201.73 - Slide way lubricants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Slide way lubricants. 3201.73 Section 3201.73... Designated Items § 3201.73 Slide way lubricants. (a) Definition. Products used to provide lubrication and... this part, will give a procurement preference for qualifying biobased slide way lubricants. By...

  17. 7 CFR 3201.73 - Slide way lubricants.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Slide way lubricants. 3201.73 Section 3201.73... Designated Items § 3201.73 Slide way lubricants. (a) Definition. Products used to provide lubrication and... this part, will give a procurement preference for qualifying biobased slide way lubricants. By...

  18. 7 CFR 2902.43 - Chain and cable lubricants.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Chain and cable lubricants. 2902.43 Section 2902.43... Items § 2902.43 Chain and cable lubricants. (a) Definition. Products designed to provide lubrication in... and cable lubricants. By that date, Federal agencies that have the responsibility for drafting...

  19. Research on bearing lubricants for use in a high vacuum

    NASA Technical Reports Server (NTRS)

    Campbell, M. E.; Hass, H.

    1972-01-01

    Work, during the research program, was concentrated on lubricant development, gear lubrication and evaluation, providing coated test specimens, advising NASA contractors about solid lubrication specific applications, and investigation of new method of attaching lubricating solids to bearing surfaces by sputtering technique.

  20. Aerodynamic Flight-Test Results for the Adaptive Compliant Trailing Edge

    NASA Technical Reports Server (NTRS)

    Cumming, Stephen B.; Smith, Mark S.; Ali, Aliyah N.; Bui, Trong T.; Ellsworth, Joel C.; Garcia, Christian A.

    2016-01-01

    The aerodynamic effects of compliant flaps installed onto a modified Gulfstream III airplane were investigated. Analyses were performed prior to flight to predict the aerodynamic effects of the flap installation. Flight tests were conducted to gather both structural and aerodynamic data. The airplane was instrumented to collect vehicle aerodynamic data and wing pressure data. A leading-edge stagnation detection system was also installed. The data from these flights were analyzed and compared with predictions. The predictive tools compared well with flight data for small flap deflections, but differences between predictions and flight estimates were greater at larger deflections. This paper describes the methods used to examine the aerodynamics data from the flight tests and provides a discussion of the flight-test results in the areas of vehicle aerodynamics, wing sectional pressure coefficient profiles, and air data.

  1. Double angle seal forming lubricant film

    DOEpatents

    Ernst, William D.

    1984-01-01

    A lubricated piston rod seal which inhibits gas leaking from a high pressure chamber on one side of the seal to a low pressure chamber on the other side of the seal. A liquid is supplied to the surface of the piston rod on the low pressure side of the seal. This liquid acts as lubricant for the seal and provides cooling for the rod. The seal, which can be a plastic, elastomer or other material with low elastic modulus, is designed to positively pump lubricant through the piston rod/seal interface in both directions when the piston rod is reciprocating. The capacity of the seal to pump lubricant from the low pressure side to the high pressure side is less than its capacity to pump lubricant from the high pressure side to the low pressure side which ensures that there is zero net flow of lubricant to the high pressure side of the seal. The film of lubricant between the seal and the rod minimizes any sliding contact and prevents the leakage of gas. Under static conditions gas leakage is prevented by direct contact between the seal and the rod.

  2. Nanopolishing by colloidal nanodiamond in elastohydrodynamic lubrication

    NASA Astrophysics Data System (ADS)

    Shirvani, Khosro A.; Mosleh, Mohsen; Smith, Sonya T.

    2016-08-01

    In this paper, the feasibility of using explosion synthesized diamond nanoparticles with an average particle size (APS) of 3-5 nm with a concentration of 1 % by weight for improving lubrication and friction in elastohydrodynamic lubrication (EHL) was investigated. Owing to the orders of magnitude increase in the viscosity of the lubricant in the EHL contact zone, diamond nanoparticles in the lubricant polish the surfaces at the nanoscale which decreases the composite roughness of contacting surfaces. The reduced composite roughness results in an increased film thickness ratio which yields lower friction. In the numerical analysis, governing equations of lubricant flow in the full elastohydrodynamic lubrication were solved, and the shear stress distribution over the fluid film was calculated. Using an abrasion model and the shear stress distribution profile, the material removal by the nanofluid containing nanoparticles and the resultant surface roughness were determined. The numerical analysis showed that in full EHL regime, the nanolubricant can reduce the composite roughness of moving surfaces. Experimental results from prior studies which exhibited surface polishing by such nanolubricants in boundary, mixed, and full elastohydrodynamic lubrication were used for comparison to the numerical model.

  3. Robust and Drain Resistant Lubricated Omniphobic Fabrics

    NASA Astrophysics Data System (ADS)

    Kido, Cassidee; Damle, Viraj; Sun, Xiaoda; Roopesh, Ajay; Doudrick, Kyle; Rykaczewski, Konrad

    2014-11-01

    The implications of omniphobic fabrics range from stainproof clothing to civilian and military protection from chemical weapons. The challenge comes in developing a product that remains effective in repelling droplets of liquids with a wide range of surface tensions even after being subjected to various stimuli imposed by human use. Omniphobic fabrics can be made by infusing hydrophobic nanoparticle coated fibers with a low surface energy lubricant. These types of lubricant impregnated surfaces can shed large deposited droplets as well as condensed microdroplets of variety of low surface tension liquids. However, here we show that lubricated omniphobic fabrics can easily lose their properties due to degradation of the nanostructure coating or drainage of the lubricant upon contact with a porous surface. We also demonstrate that this issue can be resolved with use of cross-linked polymer coated fibers that are swollen with the lubricant. Use of flexible polymers avoids structure degradation due to fabric deformation, while swelling of the polymer with lubricant minimizes lubricant drainage upon contact maintaining the omniphobic characteristics of the fabric. KR acknowledges startup funding from ASU and collaborative effort with Dr. Tim Burgin and James R. Lee from Naval Surface Warfare Center Dahlgren Division.

  4. Active damping of oscillations in a long compliant manipulator link

    NASA Astrophysics Data System (ADS)

    Baker, C. P.; Evans, M. S.; Trudnowski, D. J.; Magee, D. P.

    1993-07-01

    A flexible manipulator test bed consisting of a fifteen foot long fixed-free compliant beam (representing a compliant manipulator link) with a Shilling Titan II dextrous manipulator mounted on its free end has been constructed at Pacific Northwest Laboratory (PNL). A comprehensive dynamic model which includes flexible body effects has been developed at PNL using a commercially available multibody dynamics code. A linearized version of the model is used to develop control strategies which use inertial forces generated by movements of the dextrous manipulator to damp out induced oscillations in the beam. These control strategies are tested on the model and shown to be feasible, and then implemented in the flexible manipulator testbed. Results from the hardware experiments are analyzed and compared with the model results.

  5. Stress reduction in tungsten films using nanostructured compliant layers

    SciTech Connect

    Karabacak, Tansel; Picu, Catalin R.; Senkevich, Jay J.; Wang, G.-C.; Lu, T.-M.

    2004-11-15

    The residual stress in thin films is a major limiting factor for obtaining high quality films. We present a strategy for stress reduction in sputter deposited films by using a nanostructured compliant layer obtained by the oblique angle deposition technique, sandwiched between the film and the substrate. The technique is all in situ, does not require any lithography steps, and the nanostructured layer is made from the same material as the deposited thin film. By using this approach we were able to reduce stress values by approximately one order of magnitude in sputter deposited tungsten films. These lower stress thin films also exhibit stronger adhesion to the substrate, which retards delamination buckling. This technique allows the growth of much thicker films and has enhanced structural stability. A model is developed to explain the stress relief mechanism and the stronger adhesion associated with the presence of the nanostructured compliant layer.

  6. Bulk Metallic Glasses and Composites for Optical and Compliant Mechanisms

    NASA Technical Reports Server (NTRS)

    Hofmann, Douglas C.; Agnes, Gregory S.

    2013-01-01

    Mechanisms are used widely in engineering applications due to their ability to translate force and movement. They are found in kinematic pairs, gears, cams, linkages, and in flexure mechanisms (also known as compliant mechanisms). Mechanisms and flexures are used widely in spacecraft design, especially in the area of optics, where precise positioning of telescope mirrors requires elastic flexing of elements. A compliant mechanism is generally defined as a flexible mechanism that uses an elastic body deformation to cause a displacement (such as positing a mirror). The mechanisms are usually constructed as a single monolithic piece of material, and contain thin struts to allow for large elastic bending with low input force. This creates the largest problem with developing precise mechanisms; they must be fabricated from a single piece of metal, but are required to have strict accuracy on their dimensions. They are generally required to have high strength, elasticity, and low coefficient of thermal expansion.

  7. Interactive cytokine regulation of synoviocyte lubricant secretion.

    PubMed

    Blewis, Megan E; Lao, Brian J; Schumacher, Barbara L; Bugbee, William D; Sah, Robert L; Firestein, Gary S

    2010-04-01

    Cytokine regulation of synovial fluid (SF) lubricants, hyaluronan (HA), and proteoglycan 4 (PRG4) is important in health, injury, and disease of synovial joints, and may also provide powerful regulation of lubricant secretion in bioreactors for articulating tissues. This study assessed lubricant secretion rates by human synoviocytes and the molecular weight (MW) of secreted lubricants in response to interleukin (IL)-1beta, IL-17, IL-32, transforming growth factor-beta 1 (TGF-beta1), and tumor necrosis factor-alpha (TNF-alpha), applied individually and in all combinations. Lubricant secretion rates were assessed using ELISA and binding assays, and lubricant MW was assessed using gel electrophoresis and Western blotting. HA secretion rates were increased approximately 40-fold by IL-1beta, and increased synergistically to approximately 80-fold by the combination of IL-1beta + TGF-beta1 or TNF-alpha + IL-17. PRG4 secretion rates were increased approximately 80-fold by TGF-beta1, and this effect was counterbalanced by IL-1beta and TNF-alpha. HA MW was predominantly <1 MDa for controls and individual cytokine stimulation, but was concentrated at >3 MDa after stimulation by IL-1beta + TGF-beta1 + TNF-alpha to resemble the distribution in human SF. PRG4 MW was unaffected by cytokines and similar to that in human SF. These results contribute to an understanding of the relationship between SF cytokine and lubricant content in health, injury, and disease, and provide approaches for using cytokines to modulate lubricant secretion rates and MW to help achieve desired lubricant composition of fluid in bioreactors.

  8. Determining the Thermal Properties of Space Lubricants

    NASA Technical Reports Server (NTRS)

    Maldonado, Christina M.

    2004-01-01

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

  9. Compatibility of refrigerants and lubricants with elastomers. Quarterly report, 1 July 1992--30 September 1992

    SciTech Connect

    Hamed, G.R.; Seiple, R.H.

    1992-10-01

    Information contained in this report is designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. 97% of the swell measurements have been made to date. The other 3% of the measurements are contingent on the availability of additional quantities of R-32. Swell behavior in the fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 hours and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

  10. Compatibility of refrigerants and lubricants with elastomers. Quarterly report, 1 October 1992--30 December 1992

    SciTech Connect

    Hamed, G.R.; Seiple, R.H.

    1993-01-01

    The information contained in this report is designed to assist the air-conditioning and refrigeration industry in the selection of suitable elastomeric gasket and seal materials that will prove useful in various refrigerant and refrigeration lubricant environments. 97% of the swell measurements have been made to date. The other 3% of the measurements are contingent on availability of additional R-32. Swell behavior in the fluids have been determined using weight and in situ diameter measurements for the refrigerants and weight, diameter and thickness measurements for the lubricants. Weight and diameter measurements are repeated after 2 and 24 hours for samples removed from the refrigerant test fluids and 24 hours after removal from the lubricants.

  11. Compatibility of manufacturing process fluids with R-134a and polyolester lubricant. Final report

    SciTech Connect

    Cavestri, R.C.; Schooley, D.L.

    1996-07-01

    This report includes a broad list of processing fluids that are known to be used to manufacture air conditioning and refrigeration products. Sixty-four process fluids from this list were selected for compatibility studies with R-134a and ICI EMKARATE RL32H (32 ISO) polyolester lubricant. Solutions or suspensions of the process fluid residues in polyolester lubricant were heated for 14 days at 175{degrees}C (347{degrees}F) in evacuated sealed glass tubes containing only valve steel coupons. Miscibility tests were performed at 90 wt.% R-134a, 10 wt.% polyolester lubricant with process fluid residue contaminate and were scanned in 10{degrees}C (18{degrees}F) increments over a temperature range of ambient to -40{degrees}C (-40{degrees}F). Any sign of turbidity, haze formation or oil separation was considered the immiscibility point.

  12. Pulsatile flow in a compliant stenosed asymmetric model

    NASA Astrophysics Data System (ADS)

    Usmani, Abdullah Y.; Muralidhar, K.

    2016-12-01

    Time-varying velocity field in an asymmetric constricted tube is experimentally studied using a two-dimensional particle image velocimetry system. The geometry resembles a vascular disease which is characterized by arterial narrowing due to plaque deposition. The present study compares the nature of flow patterns in rigid and compliant asymmetric constricted tubes for a range of dimensionless parameters appearing in a human artery. A blood analogue fluid is employed along with a pump that mimics cardioflow conditions. The peak Reynolds number range is Re 300-800, while the Womersley number range considered in experiments is Wo 6-8. These values are based on the peak velocity in a straight rigid tube connected to the model, over a pulsation frequency range of 1.2-2.4 Hz. The medial-plane velocity distribution is used to investigate the nature of flow patterns. Temporal distribution of stream traces and hemodynamic factors including WSS, TAWSS and OSI at important phases of the pulsation cycle are discussed. The flow patterns obtained from PIV are compared to a limited extent against numerical simulation. Results show that the region downstream of the constriction is characterized by a high-velocity jet at the throat, while a recirculation zone, attached to the wall, evolves in time. Compliant models reveal large flow disturbances upstream during the retrograde flow. Wall shear stress values are lower in a compliant model as compared to the rigid. Cross-plane flow structures normal to the main flow direction are visible at select phases of the cycle. Positive values of largest Lyapunov exponent are realized for wall movement and are indicative of chaotic motion transferred from the flow to the wall. These exponents increase with Reynolds number as well as compliance. Period doubling is observed in wall displacement of highly compliant models, indicating possible triggering of hemodynamic events in a real artery that may cause fissure in the plaque deposits.

  13. Robotic Compliant Motion Control for Aircraft Refueling Applications

    DTIC Science & Technology

    1988-12-01

    Science in Astronautical Engineering Acceso : or NTIS -; David J. Duvall, B.S. Captain, USAF ................ December, 1988 D,: . 6 Approved for public...discussed techniques for coordinated compliant motion control of multiple ma- nipulators. He also described techniques for handling coupling between...analysis con- sidering only a single degree of freedom, the results were later shown to be equally applicable to a multiple degree of freedom arm (1, p

  14. Shari’ah Compliant Finance: Toward Economic Jihad

    DTIC Science & Technology

    2010-04-12

    principles in the areas of capital adequacy, corporate governance, risk management and transparency. The goal of the IFSB is to promote the awareness of...as excessive risk . To ensure compliance, investment firms must rely on guidance from a Shari’ah council, paid to assert the financial products...for explaining Shari’ah Compliant Financing, what it is, how it is managed , and what, if any, links there are to jihad. This monograph strives to

  15. Torque Characteristics of Solid Lubricated Precision Bearings during Oscillatory Motion.

    DTIC Science & Technology

    1994-01-31

    such as MoS2 and PTFE) rather than fluid lubricants (oils or greases). Factors favoring the use of solid lubricants are (a) low or negligible... outgassing properties, (b) low- temperature lubrication (compared to liquids), (c) simplified mechanical design (no need for labyrinth seals, reservoirs, or...lubricant applied to the races. 6 ൗ When solid lubricants are used, certain precautions depending on the material are necessary. For example, if MoS2

  16. Multivariate Parameter Sets for Optimal Synthesis of Compliant Mechanisms

    NASA Technical Reports Server (NTRS)

    Shibakov, Alex; Hull, Patrick V.; Canfield, Stephen L.; Tinker, Mike

    2005-01-01

    This paper will propose the use of control maps along with discretized elements or meshes in the design parameter set for optimizing compliant mechanisms. The use of control maps will be demonstrated to encode the motion of groups of nodes or control points within a compliant mechanism design with simple mapping rules. The technique will serve as an alternative to increased mesh size or node wandering techniques that have been proposed to increase the number of alternative design shapes that may be considered. As an alternative approach, the proposed control map parameterization has the significant benefit that it minimizes the number of design parameters necessary (parameters increase linearly with the mesh size) in describing a given design making it computationally efficient. A limited number of tiles can produce a map that has a significant effect on the final shape. If the tiles are chosen appropriately, the problems such as material overlap and non-convex mesh elements are avoided automatically. This paper will describe the implementation of these control maps and provide several examples showing their implementation in the compliant mechanism topology synthesis process.

  17. A HIPAA-compliant architecture for securing clinical images.

    PubMed

    Liu, Brent J; Zhou, Zheng; Huang, H K

    2006-06-01

    The Health Insurance Portability and Accountability Act (HIPAA, instituted April 2003) Security Standards mandate health institutions to protect health information against unauthorized use or disclosure. One approach to addressing this mandate is by utilizing user access control and generating audit trails of the various authorized as well as unauthorized user access of health data. Although most current clinical image systems [e.g., picture archiving and communication system (PACS)] have components that generate log files for application debugging purposes, there is a lack of methodology to obtain and synthesize the pertinent data from the large volumes of log data generated by these multiple components within a PACS. We have designed a HIPAA-compliant architecture specifically for tracking and auditing the image workflow of clinical imaging systems such as PACS. As an initial first step, we developed HIPAA-compliant auditing system (H-CAS) based on parts of this HIPAA-compliant architecture. H-CAS was implemented within a test-bed PACS simulator located in the Image Processing and Informatics lab at the University of Southern California. Evaluation scenarios were developed where different user types performed legal and illegal access of PACS image data within each of the different components in the PACS simulator. Results were based on whether the scenarios of unauthorized access were correctly identified and documented as well as on normal operational activity. Integration and implementation pitfalls were also noted and included.

  18. XPS analysis of 440C steel surfaces lubricated with perfluoropolyethers under sliding conditions in high vacuum

    NASA Technical Reports Server (NTRS)

    Herrera-Fierro, Pilar; Masuko, Masabumi; Jones, William R., Jr.; Pepper, Stephen V.

    1994-01-01

    This work presents the results of the X-Ray Photoelectron Spectroscopy (XPS) analysis of AISI 440C ball surfaces lubricated with perfluoropolyether (PFPE) oils after friction experiments under sliding conditions at high load in air and vacuum environments. The PFPE lubricants tested were Demnum S100, Fomblin Z-25, and Krytox 143AB. It was found that all the PFPE lubricants were degraded by sliding contact causing the formation of inorganic fluorides on the metallic surfaces and a layer of organic decomposition products. KRYTOX 143AB was the least reactive of the three lubricants tested. It was also found that metal fluoride formed at off-scar areas. This suggests the formation of reactive species, such as COF2 or R(sub f)COF, during sliding experiments, which can diffuse through the lubricant film and react with the metallic surfaces away from the contact region. Comparison of reference specimens before sliding with those that had undergone the sliding tests showed that the amount of non-degraded PFPE remaining on the surface of the balls after the sliding experiments was greater than that of the balls without sliding.

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

    SciTech Connect

    Gunsel, Selda; Pozebanchuk, Michael

    1999-04-01

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

  20. Coatings for wear and lubrication

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1978-01-01

    Recent advances in the tribological uses of rf-sputtered and ion plated films of solid film lubricants (laminar solids, soft metals, organic polymers) and wear resistant refractory compounds (carbides, nitrides, silicides) are reviewed. The sputtering and ion plating potentials and the corresponding coatings formed were evaluated relative to the friction coefficient, wear endurance life and mechanical properties. The tribological and mechanical properties for each kind of film are discussed in terms of film adherence, coherence, density, grain size, morphology, internal stresses, thickness, and substrate conditions such as temperature, topography, chemistry and dc-biasing. The ion plated metallic films in addition to improved tribological properties also have better mechanical properties such as tensile strength and fatigue life.

  1. Coatings for wear and lubrication

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1978-01-01

    In this paper we review the recent advances in the tribological uses of R.F.-sputtered and ion-plated films of solid film lubricants (laminar solids, soft metals, organic polymers) and wear-resistant refractory compounds (carbides, nitrides, silicides). The sputtering and ion-plating potentials and the corresponding coatings formed are evaluated relative to the friction coefficient, wear endurance life and mechanical properties. The tribological and mechanical properties of each kind of film are discussed in terms of film adherence, coherence, density, grain size, morphology, internal stresses and thickness and substrate conditions such as temperature, topography, chemistry and d.c. biasing. The ion-plated metallic films in addition to improved tribological properties also have better mechanical properties such as tensile strength and fatigue life.

  2. Modeling a Bouncing Droplet with a Lubrication Force

    NASA Astrophysics Data System (ADS)

    Cessna, Matthew

    2015-11-01

    In our laboratory experiments, a shallow bath of silicone oil of a particular viscosity was placed on an electromagnetic shaker where it was driven by a constant frequency just below the threshold of Faraday instability. A small droplet was then manually created on the surface of the vibrating bath and the bouncing behavior of the droplet was observed and recorded with the aid of a high speed camera. Droplets of sufficient size do not coalesce with the bath due to a thin air film that forms between them. Coalescence is avoided when the time for the bath to accelerate the droplet back into ballistic motion is shorter than the time required for the thin air film to deplete. Computer software was utilized to process the images and plot the dynamics of the droplet. The experimental data revealed that the acceleration of the droplets measured below -1 g at the moment when a droplet was being launched back into flight by the oscillating bath. We investigate whether lubrication theory accounts for these measurements and model a bouncing droplet on a vibrating bath of the same viscosity with a lubrication force to reproduce our experimental data using Matlab.

  3. Materials compatibility and lubricants research on CFC-refrigerant substitutes. Technical progress report, 1 April 1995--30 June 1995

    SciTech Connect

    Szymurski, S.R.; Hourahan, G.C.; Godwin, D.S.; Amrane, K.

    1995-08-01

    The Materials Compatibility and Lubricants Research (MCLR) program supports critical research to accelerate the introduction of CFC and HCFC refrigerant substitutes. The MCLR program addresses refrigerant and lubricant properties and materials compatibility. The primary elements of the work include data collection and dissemination, materials compatibility testing, and methods development. The work is guided by an Advisory Committee consisting of technical experts from the refrigeration and air-conditioning industry and government agencies. The AirConditioning and Refrigeration Technology Institute, Inc., (ARTI) manages and contracts multiple research projects and a data collection and dissemination effort. Detailed results from these projects are reported in technical reports prepared by each subcontractor.

  4. Materials Compatibility and Lubricants Research on CFC-refrigerant substitutes. Quarterly MCLR Program technical progress report, July 1--September 30, 1995

    SciTech Connect

    Szymurski, S.R.; Hourahan, G.C.; Godwin, D.S.; Amrane, K.

    1995-10-01

    The Materials Compatibility and Lubricants Research (MCLR) program supports critical research to accelerate the introduction of CFC and HCFC refrigerant substitutes. The MCLR program addresses refrigerant and lubricant properties and materials compatibility. The primary elements of the work include data collection and dissemination, materials compatibility testing, and methods development. This report summarizes the research conducted during the third quarter of calendar year 1995 on the following projects: Thermophysical properties of HCFC alternatives; Compatibility of manufacturing process fluids with HFC refrigerants and ester lubricants; Compatibility of motor materials used in air-conditioning for retrofits with alternative refrigerants and lubricants; Compatibility of lubricant additives with HFC refrigerants and synthetic lubricants; Products of motor burnouts; Accelerated test methods for predicting the life of motor materials exposed to refrigerant-lubricant mixtures; Investigation of flushing and clean-out methods; Investigation into the fractionation of refrigerant blends; Lean flammability limits as a fundamental refrigerant property; Effect of selected contaminants in AC and R equipment; Study of foaming characteristics; Study of lubricant circulation in systems; Evaluation of HFC-245ca for commercial use in low pressure chillers; Infrared analysis of refrigerant mixtures; Refrigerant database; Refrigerant toxicity survey; Thermophysical properties of HFC-32, HFC-123, HCFC-124 and HFC-125; Thermophysical properties of HFC-143a and HFC-152a; Theoretical evaluations of R-22 alternative fluids; Chemical and thermal stability of refrigerant-lubricant mixtures with metals; Miscibility of lubricants with refrigerants; Viscosity, solubility and density measurements of refrigerant-lubricant mixtures; Electrohydrodynamic enhancement of pool and in-tube boiling of alternative refrigerants; Accelerated screening methods; and more.

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

    NASA Technical Reports Server (NTRS)

    Stanford, Malcolm K.

    2003-01-01

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

  6. High-Temperature Solid Lubricant Coating

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Edmonds, Brian J.

    2010-01-01

    NASA PS400 is a solid lubricant coating invented for high-temperature tribological applications. This plasma-sprayed coating is a variant of the previously patented PS304 coating, and has been formulated to provide higher density, smoother surface finish, and better dimensional stability. This innovation is a new composite material that provides a means to reduce friction and wear in mechanical components. PS400 is a blend of a nickel-molybdenum binder, chrome oxide hardener, silver lubricant, and barium fluoride/calcium fluoride eutectic lubricant that can either be sprayed or deposited by other means, such as powder metallurgy. The resulting composite material is then finished by grinding and polishing to produce a smooth, self-lubricating surface.

  7. Liquid lubricants for advanced aircraft engines

    NASA Technical Reports Server (NTRS)

    Loomis, William R.; Fusaro, Robert L.

    1992-01-01

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

  8. Overview of liquid lubricants for advanced aircraft

    NASA Technical Reports Server (NTRS)

    Loomis, W. R.

    1982-01-01

    An overall status report on liquid lubricants for use in high-performance turbojet engines is presented. Emphasis is placed on the oxidation and thermal stability requirements imposed upon the lubrication system. A brief history is iven of the development of turbine engine lubricants which led to synthetic oils with their inherent modification advantages. The status and state of development of some nine candidate classes of fluids for use in advanced turbine engines are discussed. Published examples of fundamental studies to obtain a better understanding of the chemistry involved in fluid degradation are reviewed. Also, alternatives to high temperature fluid development are described. The importance of of continuing work on improving high temperature lubricant candidates and encouraging development of fluid base stocks is discussed.

  9. Liquid lubricants for advanced aircraft engines

    SciTech Connect

    Loomis, W.R.; Fusaro, R.L.

    1992-08-01

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

  10. Lubrication and cooling for high speed gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.

    1985-01-01

    The problems and failures occurring with the operation of high speed gears are discussed. The gearing losses associated with high speed gearing such as tooth mesh friction, bearing friction, churning, and windage are discussed with various ways shown to help reduce these losses and thereby improve efficiency. Several different methods of oil jet lubrication for high speed gearing are given such as into mesh, out of mesh, and radial jet lubrication. The experiments and analytical results for the various methods of oil jet lubrication are shown with the strengths and weaknesses of each method discussed. The analytical and experimental results of gear lubrication and cooling at various test conditions are presented. These results show the very definite need of improved methods of gear cooling at high speed and high load conditions.

  11. A Multipurpose Additive for Lubricating Oils,

    DTIC Science & Technology

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

  12. Liquid lubricants for advanced aircraft engines

    NASA Technical Reports Server (NTRS)

    Loomis, William R.; Fusaro, Robert L.

    1993-01-01

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

  13. Dry lubricant films for aluminum forming.

    SciTech Connect

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

    1999-03-30

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

  14. Fundamental considerations for future solid lubricants

    NASA Technical Reports Server (NTRS)

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

    1969-01-01

    Properties important to the performance of solid lubricants are discussed. Those properties include shear characteristics, coherence between particles, resistance to cold flow, adherence to the substrate, applicable chemical thermodynamics and kinetics of materials and environments, polymorphism, and rheology. The following generalizations are made: (1) chemical thermodynamics and kinetics are powerful tools for use in determining the useful environments and methods of application for solid film lubricants; (2) the primary requirement for a solid lubricant is low shear strength; (3) the rheology of solid film constituents and formulations is likely to be of vital importance to performance and life; and (4) adherence and mobility of surface films is another primary requirement for long lived solid lubricants.

  15. Potential of vegetable oils for lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  16. Tribometer for Lubrication Studies in Vacuum

    NASA Technical Reports Server (NTRS)

    Pepper, Stephen V.

    1998-01-01

    The NASA Lewis Research Center has developed a new way to evaluate the liquid lubricants used in ball bearings in space mechanisms. For this evaluation, a liquid lubricant is exercised in the rolling contact vacuum tribometer shown in the photo. This tribometer, which is essentially a thrust bearing with three balls and flat races, has contact stresses similar to those in a typical preloaded, angular contact ball bearing. The rotating top plate drives the balls in an outward-winding spiral orbit instead of a circular path. Upon contact with the "guide plate," the balls are forced back to their initial smaller orbit radius; they then repeat this spiral orbit thousands of times. The orbit rate of the balls is low enough, 2 to 5 rpm, to allow the system to operate in the boundary lubrication regime that is most stressful to the liquid lubricant. This system can determine the friction coefficient, lubricant lifetime, and species evolved from the liquid lubricant by tribodegradation. The lifetime of the lubricant charge is only few micrograms, which is "used up" by degradation during rolling. The friction increases when the lubricant is exhausted. The species evolved by the degrading lubricant are determined by a quadrupole residual gas analyzer that directly views the rotating elements. The flat races (plates) and 0.5-in.-diameter balls are of a configuration and size that permit easy post-test examination by optical and electron microscopy and the full suite of modern surface and thin-film chemical analytical techniques, including infrared and Raman microspectroscopy and x-ray photoelectron spectroscopy. In addition, the simple sphere-on-a-flat-plate geometry allows an easy analysis of the contact stresses at all parts of the ball orbit and an understanding of the frictional energy losses to the lubricant. The analysis showed that when the ball contacts the guide plate, gross sliding occurs between the ball and rotating upper plate as the ball forced back to a smaller

  17. Laboratory Based Axle Lubricant Efficiency Evaluation

    DTIC Science & Technology

    2014-07-01

    SUBJECT TERMS Axle lubricant efficiency; FMTV, SCPL, Gear Oil, Engine Oil, HMMWV, Stationary Axle Test, SAE J2360 16. SECURITY...Seconds ASTM American Society for Testing and Materials CAT Caterpillar cSt CentiStoke FMTV Family of Medium Tactical Vehicles GO Gear Oil GVW...engine, transmission, and axle gear lubricants as used in the Family of Medium Tactical Vehicles (FMTV) [3]. Fuel consumption changes were determined

  18. Anti-friction additives for lubricating oils

    SciTech Connect

    Karol, T.J.; Magaha, H.S.; Schlicht, R.C.

    1987-03-03

    A lubricating oil composition is described comprising (i) a major portion of lubricant oil; and (ii) from about 0.05 to about 10.0 wt.% of, as an additive, a product prepared by reacting a natural oil selected from the group consisting of coconut, babassu, palm, palm kernel, olive, castor, peanut, beef tallow and lard, with a (C/sub 2/-C/sub 10/) hydroxy acid and a polyamine.

  19. New Lubricants Protect Machines and the Environment

    NASA Technical Reports Server (NTRS)

    2007-01-01

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

  20. 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."

  1. Materials as additives for advanced lubrication

    DOEpatents

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

    2016-09-13

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

  2. Polymer Lubricants For Use In Vacuum

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    1989-01-01

    Report describes tests of lubricating properties of 10 polymer-based materials - in particular, polyimides - in vacuum. Commercially available materials, in forms of solid bodies and films on metals, were tested on pin-on-disk apparatus in vacuum. Best low-wear, low-friction material was 80 PMDA/20 BTDA solid-body polyimide. Friction and wear properties of most polyimides so good in vacuum that solid-lubricant additives not necessary.

  3. 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.

  4. Breathing air purification; Desiccant vs. refrigerated

    SciTech Connect

    McKay, K.L.; Swanson, A.L. )

    1986-07-01

    Carbon monoxide (CO) is a common contaminant of ambient air - levels as high as 200 ppm are not uncommon in urban, industrial, or high automotive-traffic areas. Carbon monoxide may also be produced by the oxidation of lubricating oil in overheated compressors. Air from an oil-lubricated compressor, even when an aftercooler is used, often contains significant quantities of oil mist and vapor. Even where a breathing air (non-oil-lubricated) compressor is used , oil. levels in the air taken into the compressor can still exceed Grade D standards, especially in industrial environments. Other contaminants (gaseous hydrocarbons, particulate matter, and odors), while not addressed by the Grade D criteria, are also present in harmful or objectionable levels in industrial environments; therefore, they must be taken into account in the design of the air purification systems. This paper discusses two basic types of breathing air purifiers: desiccant and refrigerated purifiers.

  5. Evaluation of selected micronized poloxamers as tablet lubricants.

    PubMed

    Desai, D; Zia, H; Quadir, A

    2007-10-01

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

  6. Test Facility Simulation Results for Aerospace Loss-of-Lubrication of Spur Gears

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Gargano, Lucas J.

    2014-01-01

    Prior to receiving airworthiness certification, extensive testing is required during the development of rotary wing aircraft drive systems. Many of these tests are conducted to demonstrate the drive system's ability to operate at extreme conditions, beyond that called for in the normal to maximum power operating range. One of the most extreme tests is referred to as the loss-of-lubrication or run dry test. During this test, the drive system is expected to last at least 30 min without failure while the primary lubrication system is disabled for predetermined, scripted flight conditions. Failure of this test can lead to a partial redesign of the drive system or the addition of an emergency lubrication system. Either of these solutions can greatly increase the aircraft drive system cost and weight and extend the schedule for obtaining airworthiness certification. Recent work at NASA Glenn Research Center focused on performing tests, in a relevant aerospace environment, to simulate the behavior of spur gears under loss-of-lubrication conditions. Tests were conducted using a test facility that was used in the past for spur gear contact fatigue testing. A loss-oflubrication test is initiated by shutting off the single into mesh lubricating jet. The test proceeds until the gears fail and can no longer deliver the applied torque. The observed failures are typically plastically deformed gear teeth, due to the high tooth temperatures, that are no longer in mesh. The effect of several different variables to gear tooth condition during loss-of-lubrication have been tested such as gear pitch, materials, shrouding, lubrication condition, and emergency supplied mist lubrication in earlier testing at NASA. Recent testing has focused on newer aerospace gear steels and imbedding thermocouples in the shrouding to measure the air-oil temperatures flung off the gear teeth. Along with the instrumented shrouding, an instrumented spur gear was also tested. The instrumented spur gear had

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  8. Krytox Lubrication Tape Study. [fluorinated lubricating oil for video tape recorders

    NASA Technical Reports Server (NTRS)

    Lee, F.

    1978-01-01

    The use of Krytox, a fluorinated oil, as a tape surface lubricant was studied for a wideband video tape recorder. In spite of the 5 to 1 head wear reduction credited to the surface lubricant, the resultant head life fell short of the 1500 hour goal.

  9. Lubrication study for Single Point Incremental Forming of Copper

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  10. Influence of liquid lubricant properties on their performance.

    NASA Technical Reports Server (NTRS)

    Wedeven, V.

    1972-01-01

    The influence of lubricant properties on performance is considered in connection with various mechanisms of lubrication. The effects of temperature and pressure on viscosity, which is important in hydrodynamic and elastohydrodynamic lubrication, is presented using a correlation postulated by Roelands. Under elastohydrodynamic conditions it is important to distinguish between the influence of lubricant properties within the inlet region and the Hertz region since each performs different functions. The role of lubricant transport properties such as surface tension is considered in connection with lubricant starvation.

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

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  12. Lubricity of well-characterized jet and broad-cut fuels by ball-on-cylinder machine

    NASA Technical Reports Server (NTRS)

    Prok, G. M.; Kim, W. S.

    1984-01-01

    A ball-on-cylinder machine (BOCM) was used to measure the lubricity of fuels. The fuels tested were well-characterized fuels available from other programs at the NASA Lewis Research Center plus some in-house mildly hydroprocessed shale fuels from other programs included Jet-A, ERBS fuel, ERBS blends, and blend stock. The BOCM tests were made before and after clay treatment of some of these fuels with both humidified air and dry nitrogen as the preconditioning and cover gas. As expected, clay treatment always reduced fuel lubricity. Using nitrogen preconditioning and cover gas always resulted in a smaller wear scar diameter than when humidified air was used. Also observed was an indication of lower lubricity with lower boiling range fuels and lower aromatic fuels. Gas chromatographic analysis indicted changes in BOCM-stressed fuels.

  13. Mechanisms of lubrication and wear of a bonded solid lubricant film

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.

    1980-01-01

    To obtain a better understanding of how bonded solid lubricant films lubricate and wear (in general), the tribological properties of polyimide-bonded graphite fluoride films were studied (in specific). A pin-on-disk type of testing apparatus was used; but in addition to sliding a hemispherically tipped rider, a rider with a 0.95 mm diameter flat area was slid against the film. This was done so that a lower, less variable contact stress could be achieved. Two stages of lubrication occurred. In the first, the film supported the load. The lubricating mechanism consisted of the shear of a thin surface layer (of the film) between the rider and the bulk of the film. The second occurred after the bonded film had worn to the substrate, and consisted of the shear of very thin lubricant films between the rider and flat plateaus generated on the metallic substrate asperities. The film wear mechanism was strongly dependent on contact stress.

  14. On the theory of compliant wall drag reduction in turbulent boundary layers

    NASA Technical Reports Server (NTRS)

    Ash, R. L.

    1974-01-01

    A theoretical model has been developed which can explain how the motion of a compliant wall reduces turbulent skin friction drag. Available experimental evidence at low speeds has been used to infer that a compliant surface selectively removes energy from the upper frequency range of the energy containing eddies and through resulting surface motions can produce locally negative Reynolds stresses at the wall. The theory establishes a preliminary amplitude and frequency criterion as the basis for designing effective drag reducing compliant surfaces.

  15. Compliant intracortical implants reduce strains and strain rates in brain tissue in vivo

    NASA Astrophysics Data System (ADS)

    Sridharan, Arati; Nguyen, Jessica K.; Capadona, Jeffrey R.; Muthuswamy, Jit

    2015-06-01

    Objective. The objective of this research is to characterize the mechanical interactions of (1) soft, compliant and (2) non-compliant implants with the surrounding brain tissue in a rodent brain. Understanding such interactions will enable the engineering of novel materials that will improve stability and reliability of brain implants. Approach. Acute force measurements were made using a load cell in n = 3 live rats, each with 4 craniotomies. Using an indentation method, brain tissue was tested for changes in force using established protocols. A total of 4 non-compliant, bare silicon microshanks, 3 non-compliant polyvinyl acetate (PVAc)-coated silicon microshanks, and 6 compliant, nanocomposite microshanks were tested. Stress values were calculated by dividing the force by surface area and strain was estimated using a linear stress-strain relationship. Micromotion effects from breathing and vascular pulsatility on tissue stress were estimated from a 5 s interval of steady-state measurements. Viscoelastic properties were estimated using a second-order Prony series expansion of stress-displacement curves for each shank. Main results. The distribution of strain values imposed on brain tissue for both compliant nanocomposite microshanks and PVAc-coated, non-compliant silicon microshanks were significantly lower compared to non-compliant bare silicon shanks. Interestingly, step-indentation experiments also showed that compliant, nanocomposite materials significantly decreased stress relaxation rates in the brain tissue at the interface (p < 0.05) compared to non-compliant silicon and PVAc-coated silicon materials. Furthermore, both PVAc-coated non-compliant silicon and compliant nanocomposite shanks showed significantly reduced (by 4-5 fold) stresses due to tissue micromotion at the interface. Significance. The results of this study showed that soft, adaptive materials reduce strains and strain rates and micromotion induced stresses in the surrounding brain tissue

  16. Structurally compliant rocket engine combustion chamber: Experimental and analytical validation

    NASA Technical Reports Server (NTRS)

    Jankovsky, Robert S.; Arya, Vinod K.; Kazaroff, John M.; Halford, Gary R.

    1994-01-01

    A new, structurally compliant rocket engine combustion chamber design has been validated through analysis and experiment. Subscale, tubular channel chambers have been cyclically tested and analytically evaluated. Cyclic lives were determined to have a potential for 1000 percent increase over those of rectangular channel designs, the current state of the art. Greater structural compliance in the circumferential direction gave rise to lower thermal strains during hot firing, resulting in lower thermal strain ratcheting and longer predicted fatigue lives. Thermal, structural, and durability analyses of the combustion chamber design, involving cyclic temperatures, strains, and low-cycle fatigue lives, have corroborated the experimental observations.

  17. High Temperature Performance Evaluation of a Compliant Foil Seal

    NASA Technical Reports Server (NTRS)

    Salehi, Mohsen; Heshmat, Hooshang; Walton, James F., II

    2001-01-01

    The key points to be gleaned from the effort reported herein are that the CFS (Compliant Foil Seal) has been demonstrated in conjunction with a foil bearing in a small gas turbine simulator at temperatures as high as 1000 F and outperformed a comparable brush seal. Having demonstrated the feasibility of the CFS, it would appear that this new seal design has application potential in a wide range of machines. What remains is to demonstrate performance at higher pressure ratios, consistent performance at large rotor excursions and the ability to manufacture the seal in much larger sizes exceeding by an order of magnitude that which has been tested to date.

  18. The status and promise of compliant substrate technology

    NASA Astrophysics Data System (ADS)

    Brown, April S.; Doolittle, W. Alan

    2000-10-01

    Compliant substrates offer significant promise as a new approach for strain management in semiconductors. The primary application is to produce device-quality highly mismatched materials on dissimilar substrates. Various implementations and processes for achieving substrate compliancy have been proposed and demonstrated. These include the use of twist-, glass-, and metal-bonds, and the use of engineered templates realized with laterally oxidized Al-containing alloys. A recent focus in our work has been on the growth of GaN on a novel and easily removable substrate — lithium gallate — for regrowth on a bonded GaN template.

  19. Motor characteristics in the control of a compliant load

    NASA Astrophysics Data System (ADS)

    Harokopos, E. G.; Mayne, R. W.

    1986-02-01

    This paper considers a servomechanism consisting of a DC-motor, a gear train and an inertial mass controlled through a compliant drive. The compliance is modeled as a spring between the gear box and inertia, and the interaction between the actuator and its load is considered. Dimensionless parameters are defined to describe this interaction, and the influence of the parameters on open- and closed-loop performance is discussed. System behavior is relatively sensitive to one particular dimensionless parameter related to damping provided by electromechanical interaction. Results of this effort illustrate the concept of quantitative controllability and indicate the possibility of controlling flexible loads conveniently by an appropriate choice of actuator parameters.

  20. Hot fire fatigue testing results for the compliant combustion chamber

    NASA Technical Reports Server (NTRS)

    Pavli, Albert J.; Kazaroff, John M.; Jankovsky, Robert S.

    1992-01-01

    A hydrogen-oxygen subscale rocket combustion chamber was designed incorporating an advanced design concept to reduce strain and increase life. The design permits unrestrained thermal expansion of a circumferential direction and, thereby, provides structural compliance during the thermal cycling of hot-fire testing. The chamber was built and test fired at a chamber pressure of 4137 kN/sq m (600 psia) and a hydrogen-oxygen mixture ratio of 6.0. Compared with a conventional milled-channel configuration, the new structurally compliant chamber had a 134 or 287 percent increase in fatigue life, depending on the life predicted for the conventional configuration.

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

    PubMed

    Uğurlu, Timuçin; Turkoğlu, Murat

    2008-04-02

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

  2. Application of Carbon Based Nano-Materials to Aeronautics and Space Lubrication

    NASA Technical Reports Server (NTRS)

    Street, Kenneth W., Jr.; Miyoshi, Kazuhisa; Wal, Randy L. Vander

    2007-01-01

    The tribology program at NASA Glenn Research Center in Cleveland, Ohio, is investigating carbon based nano-particles for their potential in advanced concept lubrication products. Service conditions range from high temperature atmospheric to low temperature vacuum. Some of the lubricants and surface coatings of tribological significance that we have evaluated include neat nano-particles, both grown in-situ and as bulk material deposited on the substrate, and nano-particles dispersed in oils which are all highly substrate interactive. We discuss results of testing these systems in a spiral orbit tribometer (SOT) and a unidirectional pin-on-disc (PoD) tribometer. A nano-onions/Krytox mixture evaluated as a lubricant for angular contact bearings in air caused a marked lowering of the coefficient of friction (CoF) (0.04 to 0.05) for the mixture with an eight-fold improvement in lifetime over that of the Krytox alone. In vacuum, no effect was observed from the nano-onions. Multi-walled nanotubes (MWNT) and graphitized MWNT were tested under sliding friction in both air and vacuum. The MWNT which were grown in-situ oriented normal to the sliding surface exhibited low CoF (0.04) and long wear lives. Bulk MWNT also generate low CoF (0.01 to 0.04, vacuum; and 0.06, air) and long wear life (>1 million orbits, vacuum; and >3.5 million, air). Dispersed graphitized MWNT were superior to MWNT and both were superior to aligned MWNT indicating that orientation is not an issue for solid lubrication. Single-walled nanotubes (SWNT) were modified by cutting into shorter segments and by fluorination. All SWNTs exhibited low CoF in air, with good wear lives. The SWNT with slight fluorination yielded an ultra-low CoF of 0.002 although the best wear life was attributed to the nascent SWNT.

  3. Experimental investigations of elastohydrodynamic lubrication

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1983-01-01

    Various experimental studies of elastohydrodynamic lubrication have been reviewed. The various types of machines used in these investigations, such as the disc, two and four ball, crossed-cylinders, and crossed-axes rolling disc machine, are described. The measurement of the most important parameters, such as film shape, film thickness, pressure, temperature, and traction, is considered. Determination of the film thickness is generally the most important of these effects since it dictates the extent to which the asperities on opposing surfaces can come into contact and thus has a direct bearing on wear and fatigue failure of the contacting surfaces. Several different techniques for measuring film thickness have been described, including electrical resistance, capacitance, X-ray, optical interferometry, laser beam diffraction, strain gage, and spring dynamometer methods. An attempt has been made to describe the basic concepts and limitations of each of these techniques. These various methods have been used by individual researchers, but there is no universally acceptable technique for measuring elastohydrodynamic film thickness. Capacitance methods have provided most of the reliable data for nominal line or rectangular conjunctions, but optical interferometry has proved to be the most effective procedure for elliptical contacts. Optical interferometry has the great advantage that it reveals not only the film thickness, but also details of the film shape over the complete area of the conjunction.

  4. NASA PS304 Lubricant Tested in World's First Commercial Oil-Free Gas Turbine

    NASA Technical Reports Server (NTRS)

    Weaver, Harold F.

    2003-01-01

    In a marriage of research and commercial technology, a 30-kW Oil-Free Capstone microturbine electrical generator unit has been installed and is serving as a test bed for long-term life-cycle testing of NASA-developed PS304 shaft coatings. The coatings are used to reduce friction and wear of the turbine engine s foil air bearings during startup and shut down when sliding occurs, prior to the formation of a lubricating air film. This testing supports NASA Glenn Research Center s effort to develop Oil-Free gas turbine aircraft propulsion systems, which will employ advanced foil air bearings and NASA s PS304 high temperature solid lubricant to replace the ball bearings and lubricating oil found in conventional engines. Glenn s Oil-Free Turbomachinery team s current project is the demonstration of an Oil-Free business jet engine. In anticipation of future flight certification of Oil-Free aircraft engines, long-term endurance and durability tests are being conducted in a relevant gas turbine environment using the Capstone microturbine engine. By operating the engine now, valuable performance data for PS304 shaft coatings and for industry s foil air bearings are being accumulated.

  5. Military Fuel and Alternative Fuel Effects on a Modern Diesel Engine Employing a Fuel-Lubricated High Pressure Common Rail Fuel Injection System

    DTIC Science & Technology

    2011-08-09

    injected, turbo- charged, air- water intercooled engine which employs a fuel- lubricated high pressure common rail pump , and piezo- electric fuel injectors...military fuels. Many of these modern HPCR systems utilize fuel-lubricated high pressure pumps , and can generate upwards of 2000-bar fuel rail pressures...steps were allowed to meet their own steady state temperatures. In addition, engine oil sump temperature was dictated by an internal jacket water

  6. Do the new materials keep their promises regarding good lubrication?

    PubMed

    Zunić, Damjan; Mihić, Kristina; Poeltner, Gustav

    2013-04-01

    To investigate the lubrication on different soft contact lenses during a week of wearing them. Twenty-five subjects participated in this research for six weeks and they wore six different soft contact lenses (Pure Vision B&L, Pure Vision II B&L, Air Optix, Focus N&D CIBA, Biofinity Cooper, Acuvue Oasys J&J). The contact lenses were randomly selected and the subjects did not know which contact lens they were wearing. Lubrication was examined on each individual three times: at the moment they first inserted the contact lenses, after all day wearing them and after one week, all using the standard "Tear analyses procedure" with the Slitlamp and immediately followed by recorded grade (1-5). After one week every test person also gave their own evaluation of the contact lenses with a grade from 1-5. After six weeks, every test person had every contact lens in both of their eyes. The results were statistically analyzed and compared: statistics of favorites of the test persons; statistics of objective results of the optometrist; statistics of differences and the correlation between right and left eye; statistics of correlation of test persons result and optometrists result. The conclusion was made after the statistical analysis.

  7. Effect of corrosive contaminants on lubricating properties of turbine oil

    SciTech Connect

    Spirkin, V.G.; Gil`mutdinov, Sh.K.

    1995-01-01

    In the operation of centrifugal and piston compressors on natural gas transmission lines, it is found that air, moisture, and hydrogen sulfide get into the lubricating oil. These contaminants, especially hydrogen sulfide, affect the lubricating properties of the oil to a great degree; however, this problem, which is directly related to the operating reliability of the moving parts of compressors, has not been studied adequately. Oxygen dissolved in the oil forms an iron oxide film on rubbing metal surfaces, protecting them from wear. When no oxygen is present, the wear becomes much more severe, all the way up to grabbing of the rubbing surfaces and pitting. Oil contaminants that form surface films with a different composition and structure, for example oxysulfide films, have received less attention. Using a procedure that we had developed, in which the oil can be saturated with hydrogen sulfide or other gases, we investigated the effects on wear rate and coefficient of friction from the presence of corrosive contaminants that find their way into turbine oil in the process of natural gas transmission.

  8. Lubrication regimes in lumbar total disc arthroplasty.

    PubMed

    Shaheen, A; Shepherd, D E T

    2007-08-01

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

  9. Wear particle analysis from grease lubricated bearings

    SciTech Connect

    Rosenlieb, W.; Maciejewski, A.S.

    1980-11-01

    Ferrographic analysis has been shown to be useful in evaluating the wear/state condition of grease lubricated components. The major achievement was the successful application of dissolving the grease utilizing a solvent mixture and making ferrograms of equal quality as to that found in oil analysis. The types of wear particles found in used grease samples are comparative to those found in oil lubricated systems. Work is presently being performed on grease lubricated taper roller bearings, similar to the test conditions utilized in this study. The analysis of the grease samples was qualitative vs quantitative. Due to the uneven distribution of wear particulate in the grease and the relatively small amount of grease used in making the ferrograms. The primary emphasis was placed upon size distribution, morphology and elemental composition. The results of the ferrogram analysis showed a good correlation to those of the SKF personnel in terms of monitoring the wear state/condition of the bearings throughout their life. However, the on-condition monitoring of grease lubricated components in the field, is complicated by the physical location of the components and inaccessibility by maintenance personnel to remove grease samples. Where accessibility is no problem, this technique is highly recommended. As it appears presently, this analysis technique seems best suited to the examination of grease obtained from dismantled grease lubricated components or in design applications.

  10. Highly viscous sodium hyaluronate and joint lubrication.

    PubMed

    Mori, S; Naito, M; Moriyama, S

    2002-01-01

    We studied the natural lubrication mechanism of synovial joints. We determined the effect of sodium hyaluronate (HA) on lubricating joints without the normal lubrication mechanism. The coefficient of friction (CF) of fresh pig hip joints was measured with the cartilage intact, washed, scoured with gauze and finally with sandpaper, to model cartilage degradation. Three formulas of HA (8 x 10(5) daltons 1%, 20 x 10(5) daltons 1%, 20 x 10(5) daltons 1.5%) and physiologic saline were used as lubricants. We observed the cartilage using light microscopy (LM) and scanning electron microscopy (SEM). The latter showed that the most superficial layer observed in the washed joint was disrupted after gauze scouring. Compared with intact cartilage the CF did not increase with washing. CF increased more after scouring with sandpaper than with gauze. Each formula of HA decreased the CF of joints scoured with gauze, but only the two more viscous HA formulas decreased the CF of sandpaper-scoured joints. A negative correlation was found between the CF of the sandpaper-scoured joints and the logHA viscosity (r = -0.733, P = 0.0001), suggesting that HA with higher viscosity was more effective in lubricating the joints.

  11. Tribology of the lubricant quantized sliding state.

    PubMed

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

    2009-11-07

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

  12. Enhancement of Perfluoropolyether Boundary Lubrication Performance

    NASA Technical Reports Server (NTRS)

    Jones, W. R., Jr.; Ajayi, O. O.; Wedeven, L. D.

    1996-01-01

    A ball bearing simulator operating under starved conditions was used to perform screening tests to evaluate the boundary lubrication performance of a branched perfluoropolyether (PFPE), K-143 AB. Several approaches to enhance boundary lubrication were studied. These included: (1) soluble boundary additives, (2) bearing surface modifications, (3) 'run-in' surface films, and (4) ceramic bearing components. In addition, results were compared with two non-perfluorinated liquid lubricant formulations. Based on these tests, the following tentative conclusions can be made: (1) Substantial improvements in boundary lubrication performance were observed with a beta-diketone boundary additive and a tricresyl phosphate (TCP) liquid surface pretreatment, (2) the use of rough Si3N4 balls (R(sub a) = 40 micro-inch) also provided increases in test duration, but with concomitant abrasive wear, (3) moderate improvements were seen with two boundary additives (a phosphine and a phosphatriazine) and a neat (100%) fluid (a carboxylic acid terminated PFPE); and small improvements with surface pretreatments with synthetic hydrocarbons, a polytetrafluoroethylene (PTFE) coating, and TiC coated 440 C and smooth Si3N4 balls (R(sub a) = 1 micro-inch), and (4) two non-PFPE lubricant formulations (a polyalphaolefin (PAO) and synthetic hydrocarbon) yielded substantial improvements.

  13. Compliant topology optimization for planar passive flap micro valve.

    PubMed

    Yoon, Gil Ho

    2014-10-01

    This paper reports the compliant topology optimization for planar passive flap micro valve considering fluid-structure interaction with a monolithic approach. Although flap valve type check valve is easy to manufacture and use for the applications for Bio/Nano/MEMS, its structural optimization has been seldom conducted so far. The size of the Bio/Nano/MEMS devices becomes smaller and the simple straight type micro valve structure is required to be optimized considering fluid speed. To address this optimization problem, the structural topology optimization scheme which designs optimal topologies is applied for a flap type check valve structure. To consider the coupling effects of fluid domain and structural domain, the monolithic finite element approach is employed. In the new analysis approach, solid domain is simulated by introducing the inverse permeability in the Navier-Stokes equation and the fluid stress filter in the linear elasticity equation. Also it is a new idea that fluid domain is simulated by finite elements with a weak Young's modulus in the linear elasticity equation. The mutual couplings between fluid and structure are considered by the introduction of the deformation tensor which is one of the basic concepts of the continuum mechanism. By distributing material properties inside a design domain for compliant flap, optimal flap structures can be constructed with different fluid speeds. By investigating the optimal layouts of several passive flap designs, we prove that the structural topology optimization can provide optimal layouts for Bio, Nano, and MEMS applications.

  14. Investigation of the Mechanical Performance of Compliant Thermal Barriers

    NASA Technical Reports Server (NTRS)

    DeMange, Jeffrey J.; Bott, Robert J.; Dunlap, Patrick H.

    2011-01-01

    Compliant thermal barriers play a pivotal role in the thermal protection systems of advanced aerospace vehicles. Both the thermal properties and mechanical performance of these barriers are critical in determining their successful implementation. Due to the custom nature of many thermal barriers, designers of advanced spacecraft have little guidance as to the design, selection, and implementation of these elements. As part of an effort to develop a more fundamental understanding of the interrelationship between thermal barrier design and performance, mechanical testing of thermal barriers was conducted. Two different types of thermal barriers with several core insulation density levels ranging from 62 to 141 kg/cu m were investigated. Room-temperature compression tests were conducted on samples to determine load performance and assess thermal barrier resiliency. Results showed that the loading behavior of these thermal barriers was similar to other porous, low-density, compliant materials, such as elastomeric foams. Additionally, the insulation density level had a significant non-linear impact on the stiffness and peak loads of the thermal barriers. In contrast, neither the thermal barrier type nor the level of insulation density significantly influenced the room-temperature resiliency of the samples.

  15. Compliant threads maximize spider silk connection strength and toughness.

    PubMed

    Meyer, Avery; Pugno, Nicola M; Cranford, Steven W

    2014-09-06

    Millions of years of evolution have adapted spider webs to achieve a range of functionalities, including the well-known capture of prey, with efficient use of material. One feature that has escaped extensive investigation is the silk-on-silk connection joints within spider webs, particularly from a structural mechanics perspective. We report a joint theoretical and computational analysis of an idealized silk-on-silk fibre junction. By modifying the theory of multiple peeling, we quantitatively compare the performance of the system while systematically increasing the rigidity of the anchor thread, by both scaling the stress-strain response and the introduction of an applied pre-strain. The results of our study indicate that compliance is a virtue-the more extensible the anchorage, the tougher and stronger the connection becomes. In consideration of the theoretical model, in comparison with rigid substrates, a compliant anchorage enormously increases the effective adhesion strength (work required to detach), independent of the adhered thread itself, attributed to a nonlinear alignment between thread and anchor (contact peeling angle). The results can direct novel engineering design principles to achieve possible load transfer from compliant fibre-to-fibre anchorages, be they silk-on-silk or another, as-yet undeveloped, system.

  16. Dual-arm generalized compliant motion with shared control

    NASA Astrophysics Data System (ADS)

    Backes, Paul G.

    1993-03-01

    A multiple arm generalized compliant motion robot control system governs dual multi-joint robot arms handling an object with both of the arms in accordance with input parameters governing plural respective behaviors to be exhibited by the robot in respective behavior spaces simultaneously. A move-squeeze decomposition processor computes actual move and squeeze decomposition forces based upon current robot force sensor outputs. A compliant motion processor transforms plural object position perturbations of the plural behaviors from the respective behavior spaces to a common space and computes a relative transformation to a behavior-commanded object position in accordance with the object position perturbations of the plural behaviors. A kinematics processor updates a transformation to a current commanded object position based upon the relative transformation to the behavior-commanded object position. A multiple arm squeeze control processor computes from appropriate squeeze force input parameters and from actual squeeze forces for each of the arms, a squeeze control position perturbation for each of the arms, to provide squeeze control. An inverse kinematics processor computes from the commanded object position transformation and from the squeeze control position perturbation, new robot joint angles, and controls respective joints of the robot arms in accordance with the new robot joint angles.

  17. Dual arm generalized compliant motion with shared control

    NASA Astrophysics Data System (ADS)

    Backes, Paul G.

    1993-03-01

    A multiple arm generalized compliant motion robot control system governs dual multi-joint robot arms handling an object with both of the arms in accordance with input parameters governing plural respective behaviors to be exhibited by the robot in respective behavior spaces simultaneously. A move-squeeze decomposition processor computes actual move and squeeze decomposition forces based upon current robot force sensor outputs. A compliant motion processor transforms plural object position perturbations of the plural behaviors from the respective behavior spaces to a common space and computes a relative transformation to a behavior-commanded object position in accordance with the object position perturbations of the plural behaviors. A kinematics processor updates a transformation to a current commanded object position based upon the relative transformation to the behavior-commanded object position. A multiple arm squeeze control processor computes from appropriate squeeze force input parameters and from actual squeeze forces for each of the arms, a squeeze control position perturbation for each of the arms, to provide squeeze control. An inverse kinematics processor computes from the commanded object position transformation and from the squeeze control position perturbation, new robot joint angles, and controls respective joints of the robot arms in accordance with the new robot joint angles.

  18. A HIPAA-compliant architecture for securing clinical images

    NASA Astrophysics Data System (ADS)

    Liu, Brent J.; Zhou, Zheng; Huang, H. K.

    2005-04-01

    The HIPAA (Health Insurance Portability and Accountability Act, Instituted April 2003) Security Standards mandate health institutions to protect health information against unauthorized use or disclosure. One approach to addressing this mandate is by utilizing user access control and generating audit trails of the various authorized as well as unauthorized user access of health data. Although most current clinical image systems (eg, PACS) have components that generate log files as a solution to address the HIPAA mandate, there is a lack of methodology to obtain and synthesize the pertinent data from the large volumes of log file data generated by these multiple components within a PACS. We have designed and developed a HIPAA Compliant Architecture specifically for tracking and auditing the image workflow of clinical imaging systems such as PACS. As an initial first step, a software toolkit was implemented based on the HIPAA Compliant architecture. The toolkit was implemented within a testbed PACS Simulator located in the Image Processing and Informatics (IPI) lab at the University of Southern California. Evaluation scenarios were developed where different user types performed legal and illegal access of PACS image data within each of the different components in the PACS Simulator. Results were based on whether the scenarios of unauthorized access were correctly identified and documented as well as normal operational activity.

  19. Novel compliant electrodes based on platinum salt reduction

    NASA Astrophysics Data System (ADS)

    Delille, Remi; Urdaneta, Mario; Hsieh, Kuangwen; Smela, Elisabeth

    2006-03-01

    A compliant electrode material is presented that was inspired by the electroding process used to manufacture ionic polymer-metal composites (IPMCs). However, instead of an ion-exchange membrane, a UV-curable acrylated urethane elastomer is employed. The electrode material consists of the UV-curable elastomer (Loctite 3108) loaded with tetraammineplatinum(II) chloride salt particles through physical mixing and homogenization. The composite material is made conductive by immersion in a reducing agent, sodium borohydride, which reduces the salt to platinum metal on the surface of the elastomer film. Because the noble metal is mixed into the elastomer precursor as a salt, the amount of UV light absorbed by the precursor is not significantly reduced, and the composite loses little photopatternability. As a result meso-scale electrodes of varying geometries can be formed by exposing the precursor/salt mixture through a mask. The materials are mechanically and electrically characterized. The percolation threshold of the composite is estimated to be 9 vol. % platinum salt, above which the compliant electrode material exhibits a maximum conductivity of 1 S/cm. The composite maintains its electrical conductivity under axial tensile strains of up to 40%.

  20. Compliant threads maximize spider silk connection strength and toughness

    PubMed Central

    Meyer, Avery; Pugno, Nicola M.; Cranford, Steven W.

    2014-01-01

    Millions of years of evolution have adapted spider webs to achieve a range of functionalities, including the well-known capture of prey, with efficient use of material. One feature that has escaped extensive investigation is the silk-on-silk connection joints within spider webs, particularly from a structural mechanics perspective. We report a joint theoretical and computational analysis of an idealized silk-on-silk fibre junction. By modifying the theory of multiple peeling, we quantitatively compare the performance of the system while systematically increasing the rigidity of the anchor thread, by both scaling the stress–strain response and the introduction of an applied pre-strain. The results of our study indicate that compliance is a virtue—the more extensible the anchorage, the tougher and stronger the connection becomes. In consideration of the theoretical model, in comparison with rigid substrates, a compliant anchorage enormously increases the effective adhesion strength (work required to detach), independent of the adhered thread itself, attributed to a nonlinear alignment between thread and anchor (contact peeling angle). The results can direct novel engineering design principles to achieve possible load transfer from compliant fibre-to-fibre anchorages, be they silk-on-silk or another, as-yet undeveloped, system. PMID:25008083

  1. Physical and chemical properties of industrial mineral oils affecting lubrication

    SciTech Connect

    Godfrey, D.; Herguth, W.R.

    1995-05-01

    The physical and chemical properties of mineral oils that affect lubrication are reviewed. Recognition of these properties is useful for designing lubrication systems, diagnostics, friction and wear problems, and selecting appropriate test methods.

  2. Tests of a sputtered MoS2 lubricant film in various environments

    NASA Technical Reports Server (NTRS)

    Vest, C. E.

    1976-01-01

    This paper discusses conditions and results of several tests of a DC sputtered MoS2 dry lubricant film. The test components were miniature precision ball bearings and rings and blocks; the surrounding atmospheres were laboratory air, pure helium, vacuum to 10 to the -8th power torr, and a perfluoroalkylpolyether oil. The results showed that the lubricant would perform satisfactorily under lightly loaded (450 gm) ball bearings in vacuum and would not perform well under a 66-kg load in air, a 132-kg load in helium, or a 330-kg load under oil. These tests and others show that the sputtered MoS2 film has some desirable features for space applications as well as some definite limitations.

  3. Graphite fluoride lubrication - The effect of fluorine content, atmosphere, and burnishing technique

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.

    1975-01-01

    Eight different graphite fluoride compounds with fluorine to carbon ratios varying from 0.25 to 1.1 were evaluated as burnished films in order to determine the effect of fluorine content on the solid lubricant properties of graphite fluoride. For comparison, similar experiments were conducted on graphite burnished films. It was found that even a small amount of fluorine in graphite fluoride with fluorine to carbon ratio of 0.25 improved the lubricating properties of graphite. However, such factors as burnishing atmosphere, burnishing technique, test atmosphere, and specimen temperature affected the results as much as varying the fluorine to carbon ratio of the compound. Best life was found for films that were machine-burnished in moist air and tested in moist air.

  4. Graphite fluoride lubrication: The effect of fluorine content, atmosphere, and burnishing technique

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.

    1975-01-01

    Eight different graphite fluoride compounds with fluorine to carbon ratios varying from x = 0.25 to 1.1 were evaluated as burnished films in order to determine the effect of fluorine content on the solid lubricant properties of graphite fluoride. For comparison, similar experiments were conducted on graphite burnished films. It was found that even a small amount of fluorine in graphite fluoride (CF sub 0.25) sub n improved the lubricating properties of graphite. Such factors as burnishing atmosphere, burnishing technique, test atmosphere, and specimen temperature affected the results as much as varying the fluorine to carbon ratio of the compound. Best life was found for films that were machine-burnished in moist air and tested in moist air.

  5. Effect of fullerene containing lubricants on wear resistance of machine components in boundary lubrication

    NASA Astrophysics Data System (ADS)

    Titov, Andriy

    Fullerenes, a new form of carbon nanomaterials, possess unique physical and mechanical properties that make their use as additives to liquid lubricants potentially beneficial. The goal of this study was to investigate the effect of fullerene containing lubricants on wear resistance of steel-bronze couples operating under boundary lubrication conditions. A mathematical model of deformed asperity contact was built to calculate real contact area and real contact pressure. Computer controlled wear friction testing methodology and equipment were designed, developed and implemented for obtaining reliable and objective experimental data. In addition, optical and scanning electron microscopy and standard surface texture analysis were employed. Heavy duty motor oil SAE 10 was modified by admixing fullerenes C60, a fullerene mixture of C60 and C70, fullerene containing soot, and graphite powder. The experiments showed that all of the selected fullerene additives dissolved in liquid lubricants reduce wear of the tested materials. In addition, it was found that despite improvements in wear resistance, the selected modified lubricants did not significantly change friction characteristics. Improvement of wear resistance of contact surfaces operating with fullerene modified lubricants can be explained by the presence of fullerenes in real contact while the liquid lubricant is squeezed out. Fullerenes are considered to function as minute hard particles that do not break down under applied normal force, and tend to separate direct contact of functional surfaces of selected materials.

  6. Correlation of rheological characteristics of lubricants with transmission efficiency measurements

    NASA Technical Reports Server (NTRS)

    Jacobson, B. O.; Hamrock, B. J.; Hoeglund, E.

    1985-01-01

    The power efficiency of a helicopter transmission has been analyzed for 11 lubricants by looking at the Newtonian and non-Newtonian properties of the lubricants. A non-Newtonian property of the lubricants was the limiting shear strength proportionality constant. The tests were performed on a high-pressure, short-time shear strength analyzer. A power efficiency formula that was obtained by analyzing the Newtonian and non-Newtonian properties of the lubricants is presented in detail.

  7. Practical Applications and Uses of Solid Lubricant Films

    NASA Technical Reports Server (NTRS)

    Stupp, B. C.

    1984-01-01

    Practical applications are illustrated with discussions covering the reasons for use of solid lubricants, required performance, lubricant selection, and results obtained for the various examples shown. The applications described cover a broad range of solid lubricants. Included are soft lamellar compounds, organic polymers, soft elemental metals, oxides and compounds for high temperature use. The illustrations selected cover a broad range of lubricant application techniques delineating the reasons for the different processing procedures which include bonded films, plasma spraying, sputtering, ion plating and electrodeposition.

  8. 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.

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

    PubMed

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

    2013-06-01

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

  10. Electrophoretically-deposited solid film lubricants

    SciTech Connect

    Dugger, M.T.; Panitz, J.K.J.; Vanecek, C.W.

    1995-04-01

    An aqueous-based process that uses electrophoresis to attract powdered lubricant in suspension to a charged target was developed. The deposition process yields coatings with low friction, complies with environmental safety regulations, requires minimal equipment, and has several advantages over processes involving organic binders or vacuum techniques. This work focuses on development of the deposition process, includes an analysis of the friction coefficient of the material in sliding contact with stainless steel under a range of conditions, and a functional evaluation of coating performance in a precision mechanical device application. Results show that solid lubricant films with friction coefficients as low as 0.03 can be produced. A 0.03 friction coefficient is superior to solid lubricants with binder systems and is comparable to friction coefficients generated with more costly vacuum techniques.

  11. Rheological effects on friction in elastohydrodynamic lubrication

    NASA Technical Reports Server (NTRS)

    Trachman, E. G.; Cheng, H. S.

    1973-01-01

    An analytical and experimental investigation is presented of the friction in a rolling and sliding elastohydrodynamic lubricated contact. The rheological behavior of the lubricant is described in terms of two viscoelastic models. These models represent the separate effects of non-Newtonian behavior and the transient response of the fluid. A unified description of the non-Newtonian shear rate dependence of the viscosity is presented as a new hyperbolic liquid model. The transient response of viscosity, following the rapid pressure rise encountered in the contact, is described by a compressional viscoelastic model of the volume response of a liquid to an applied pressure step. The resulting momentum and energy equations are solved by an iterative numerical technique, and a friction coefficient is calculated. The experimental study was performed, with two synthetic paraffinic lubricants, to verify the friction predictions of the analysis. The values of friction coefficient from theory and experiment are in close agreement.

  12. Sputtering technology in solid film lubrication

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1978-01-01

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

  13. Rheology and lubricity of hyaluronic acid

    NASA Astrophysics Data System (ADS)

    Liang, Jing; Krause, Wendy E.

    2007-03-01

    The polyelectrolyte hyaluronic acid (HA, hyaluronan) is an important component in synovial fluid (i.e., the fluid that lubricates our freely moving joints). Its presence results in highly viscoelastic solutions. In comparison to healthy synovial fluid, diseased fluid has a reduced viscosity and loss of lubricity. In osteoarthritis the reduction in viscosity results from a decline in both the molecular weight and concentration of HA. In our investigation, we attempt to correlate the rheological properties of HA solutions to changes in lubrication and wear. A nanoindenter will be used to evaluate the coefficient of friction and wear properties between the nanoindenter tip and ultrahigh molecular weight polyethylene in both the presence and absence of a thin film of HA solution.

  14. Modeling the Extreme-Pressure Lubricating Interface

    NASA Astrophysics Data System (ADS)

    Kaltchev, Matey; Gao, Feng; Lara-Romero, Javier; Tysoe, Wilfred

    2005-04-01

    Extreme-pressure lubricants are currently widely used in various areas of applications. However, despite of their common use, the fundamental aspects of the mechanism in which these lubricants reduce the friction coefficient are not clear yet. Earlier macrotribological experiments using chlorinated hydrocarbons have shown remarkable effectiveness. It has been proven that thin films that resemble those formed under tribological conditions can also be synthesized in ultrahigh vacuum when beams of chlorinated hydrocarbons are directed onto a clean iron surface. Here results obtained using X-ray photoelectron spectroscopy, temperature programmed desorption, atomic force microscopy and microtribological measurements of these films are presented. Substantial information about the fundamental properties and structure of this model lubricating interface is revealed. A mechanism of the formation of the interface under tribological conditions is also suggested.

  15. Allergy to spermicidal lubricant in a contraceptive.

    PubMed

    van Ulsen, J; Stolz, E; van Joost, T; Geursen-Reitsma, A M

    1987-08-01

    Allergic contact dermatitis is reported in a patient using a condom with the spermicidal lubricant Tectol. A 36 year old female, with no history of dermatitis or pruritus of the vagina or vulva, experienced itchy dermatitis 24-48 hours after her partner used a Durex Top Safe contraceptive containing Tectol. The dermatitis appeared on the neck, upper legs, underarms, and trunk area. When another contraceptive was used Durex Featherlite (without Tectol), the patient experienced no problems. Patch tests concluded that the Tectol lubricant was the cause for the reaction in the patient. Transmission of the lubricant to the patient occurred when the patient's partner, after handling the contraceptive (Durex Top Safe) during intercourse, placed his hands on the patient's body. To which exact element of Tectol the patient was sensitized could not be determined as the patient refused further treatment.

  16. Used lubricating oil recycling using hydrocarbon solvents.

    PubMed

    Hamad, Ahmad; Al-Zubaidy, Essam; Fayed, Muhammad E

    2005-01-01

    A solvent extraction process using new hydrocarbon solvents was employed to treat used lubricant oil. The solvents used were liquefied petroleum gas (LPG) condensate and stabilized condensate. A demulsifier was used to enhance the treatment process. The extraction process using stabilized condensate demonstrated characteristics that make it competitive with existing used oil treatment technologies. The process is able to reduce the asphaltene content of the treated lubricating oil to 0.106% (w/w), the ash content to 0.108%, and the carbon residue to 0.315% with very low levels of contaminant metals. The overall yield of oil is 79%. The treated used oil can be recycled as base lubricating oil. The major disadvantage of this work is the high temperature of solvent recovery. Experimental work and results are presented in detail.

  17. Micro-droplets lubrication film thickness dynamics

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  18. A vacuum four-ball tribometer to evaluate liquid lubricants for space applications

    NASA Technical Reports Server (NTRS)

    Masuko, Masabumi; Jones, William R., Jr.; Jansen, Ralph; Ebihara, Ben; Pepper, Stephen V.; Helmick, Larry S.

    1993-01-01

    The design and operation of a vacuum tribometer, based on the four-ball configuration, is described. This tribometer evaluates the tribological characteristics of liquid lubricants for space applications. Operating conditions include: room temperature, loads to approximately 1000N, speeds to approximately 500 rpm, and pressures of approximately 10(exp -6)Pa. Tests can also be run at atmospheric pressure with air or nitrogen. Some typical test results are included.

  19. 7 CFR 3201.86 - Pneumatic equipment lubricants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Pneumatic equipment lubricants. 3201.86 Section 3201... PROCUREMENT Designated Items § 3201.86 Pneumatic equipment lubricants. (a) Definition. Lubricants designed... this part, will give a procurement preference for qualifying biobased pneumatic equipment...

  20. 7 CFR 3201.43 - Chain and cable lubricants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Chain and cable lubricants. 3201.43 Section 3201.43... Designated Items § 3201.43 Chain and cable lubricants. (a) Definition. Products designed to provide... chain and cable lubricants. By that date, Federal agencies that have the responsibility for drafting...

  1. 7 CFR 3201.43 - Chain and cable lubricants.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Chain and cable lubricants. 3201.43 Section 3201.43... Designated Items § 3201.43 Chain and cable lubricants. (a) Definition. Products designed to provide... chain and cable lubricants. By that date, Federal agencies that have the responsibility for drafting...

  2. 7 CFR 3201.86 - Pneumatic equipment lubricants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Pneumatic equipment lubricants. 3201.86 Section 3201... PROCUREMENT Designated Items § 3201.86 Pneumatic equipment lubricants. (a) Definition. Lubricants designed... this part, will give a procurement preference for qualifying biobased pneumatic equipment...

  3. 7 CFR 3201.43 - Chain and cable lubricants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Chain and cable lubricants. 3201.43 Section 3201.43... Designated Items § 3201.43 Chain and cable lubricants. (a) Definition. Products designed to provide... chain and cable lubricants. By that date, Federal agencies that have the responsibility for drafting...

  4. Gravimetric Determination of Sediment in Turbine Engine Lubricating Oils.

    DTIC Science & Technology

    noncombustible sediment present in aircraft turbine engine lubricating oils . Both MIL-L-7808 and MIL-L-23699 lubricants were investigated. These...temperature. When these oils were heated to 140 F, they easily passed through a silver membrane filter. A test procedure for the gravimetric measurement of particulate contamination in turbine engine lubricating oils is proposed. (Author)

  5. FY2013 Progress Report for Fuel & Lubricant Technologies

    SciTech Connect

    none,

    2014-02-01

    Annual progress report for Fuel & Lubricant Technologies. The Fuel & Lubricant Technologies Program supports fuels and lubricants research and development (R&D) to provide vehicle manufacturers and users with cost-competitive options that enable high fuel economy with low emissions, and contribute to petroleum displacement.

  6. FY2014 Fuel & Lubricant Technologies Annual Progress Report

    SciTech Connect

    Stork, Kevin

    2016-02-01

    Annual progress report for Fuel & Lubricant Technologies. The Fuel & Lubricant Technologies Program supports fuels and lubricants research and development (R&D) to provide vehicle manufacturers and users with cost-competitive options that enable high fuel economy with low emissions, and contribute to petroleum displacement.

  7. Wormgear geometry adopted for implementing hydrostatic lubrication and formulation of the lubrication problem

    NASA Technical Reports Server (NTRS)

    Sun, D. C.; Yuan, Qin

    1995-01-01

    The geometrical parameters for a wormgear intended to be used as the transmission in advanced helicopters are finalized. The resulting contact pattern of the meshing tooth surfaces is suitable for the implementation of hydrostatic lubrication Fluid film lubrication of the contact is formulated considering external pressurization as well as hydrodynamic wedge and squeeze actions. The lubrication analysis is aimed at obtaining the oil supply pressure needed to separate the worm and gear surfaces by a prescribed minimum film thickness. The procedure of solving the mathematical problem is outlined.

  8. 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

    2016-08-04

    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.

  9. Regulated and unregulated emissions from modern 2010 emissions-compliant heavy-duty on-highway diesel engines.

    PubMed

    Khalek, Imad A; Blanks, Matthew G; Merritt, Patrick M; Zielinska, Barbara

    2015-08-01

    The U.S. Environmental Protection Agency (EPA) established strict regulations for highway diesel engine exhaust emissions of particulate matter (PM) and nitrogen oxides (NOx) to aid in meeting the National Ambient Air Quality Standards. The emission standards were phased in with stringent standards for 2007 model year (MY) heavy-duty engines (HDEs), and even more stringent NOX standards for 2010 and later model years. The Health Effects Institute, in cooperation with the Coordinating Research Council, funded by government and the private sector, designed and conducted a research program, the Advanced Collaborative Emission Study (ACES), with multiple objectives, including detailed characterization of the emissions from both 2007- and 2010-compliant engines. The results from emission testing of 2007-compliant engines have already been reported in a previous publication. This paper reports the emissions testing results for three heavy-duty 2010-compliant engines intended for on-highway use. These engines were equipped with an exhaust diesel oxidation catalyst (DOC), high-efficiency catalyzed diesel particle filter (DPF), urea-based selective catalytic reduction catalyst (SCR), and ammonia slip catalyst (AMOX), and were fueled with ultra-low-sulfur diesel fuel (~6.5 ppm sulfur). Average regulated and unregulated emissions of more than 780 chemical species were characterized in engine exhaust under transient engine operation using the Federal Test Procedure cycle and a 16-hr duty cycle representing a wide dynamic range of real-world engine operation. The 2010 engines' regulated emissions of PM, NOX, nonmethane hydrocarbons, and carbon monoxide were all well below the EPA 2010 emission standards. Moreover, the unregulated emissions of polycyclic aromatic hydrocarbons (PAHs), nitroPAHs, hopanes and steranes, alcohols and organic acids, alkanes, carbonyls, dioxins and furans, inorganic ions, metals and elements, elemental carbon, and particle number were substantially (90

  10. Performance of Simple Gas Foil Thrust Bearings in Air

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert J.

    2012-01-01

    Foil bearings are self-acting hydrodynamics devices used to support high speed rotating machinery. The advantages that they offer to process fluid lubricated machines include: high rotational speed capability, no auxiliary lubrication system, non-contacting high speed operation, and improved damping as compared to rigid hydrodynamic bearings. NASA has had a sporadic research program in this technology for almost 6 decades. Advances in the technology and understanding of foil journal bearings have enabled several new commercial products in recent years. These products include oil-free turbochargers for both heavy trucks and automobiles, high speed electric motors, microturbines for distributed power generation, and turbojet engines. However, the foil thrust bearing has not received a complimentary level of research and therefore has become the weak link of oil-free turbomachinery. In an effort to both provide machine designers with basic performance parameters and to elucidate the underlying physics of foil thrust bearings, NASA Glenn Research Center has completed an effort to experimentally measure the performance of simple gas foil thrust bearing in air. The database includes simple bump foil supported thrust bearings with full geometry and manufacturing techniques available to the user. Test conditions consist of air at ambient pressure and temperatures up to 500 C and rotational speeds to 55,000 rpm. A complete set of axial load, frictional torque, and rotational speed is presented for two different compliant sub-structures and inter-pad gaps. Data obtained from commercially available foil thrust bearings both with and without active cooling is presented for comparison. A significant observation made possible by this data set is the speed-load capacity characteristic of foil thrust bearings. Whereas for the foil journal bearing the load capacity increases linearly with rotational speed, the foil thrust bearing operates in the hydrodynamic high speed limit. In

  11. Thermocapillary motion on lubricant-impregnated surfaces

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

  12. Method for reclaiming waste lubricating oils

    DOEpatents

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

    1978-01-01

    A method for purifying and reclaiming used lubricating oils containing additives such as detergents, antioxidants, corrosion inhibitors, extreme pressure agents and the like and other solid and liquid contaminants by preferably first vacuum distilling the used oil to remove water and low-boiling contaminants, and treating the dried oil with a solvent mixture of butanol, isopropanol and methylethyl ketone which causes the separation of a layer of sludge containing contaminants, unspent additives and oxidation products. After solvent recovery, the desludged oil is then subjected to conventional lubricating oil refining steps such as distillation followed by decolorization and deodorization.

  13. Rotor self-lubricating axial stop

    NASA Technical Reports Server (NTRS)

    Blount, Dale H. (Inventor)

    1989-01-01

    A plurality of lubricating plugs are disposed in the stationary backup face adjacent to the axial stop face of a rotating impeller mounted in a turbopump for pumping liquid oxygen or liquid hydrogen. The stop face and the backup face are those surfaces which engage when the axial load on the impeller exceeds the load balancing capability. The plugs have a truncated conical configuration so as to be trapped in the backup face, and are disposed at varying radii on the face to provide complete surface lubrication. The plugs may be formed from Teflon, Kel-F or bronze filled Teflon.

  14. Training Children with Autism Spectrum Disorders to Be Compliant with an Oral Assessment

    ERIC Educational Resources Information Center

    Cuvo, Anthony J.; Godard, Anna; Huckfeldt, Rachel; DeMattei, Ronda

    2010-01-01

    Little research has been conducted on teaching children with autism spectrum disorders to be compliant with dental procedures. This study evaluated a behavioral package to train children with autism spectrum disorders to be compliant with an 8 component oral assessment. After a dental hygienist performed an assessment pretest, noncompliance on…

  15. Using Taxonomic Indexing Trees to Efficiently Retrieve SCORM-Compliant Documents in e-Learning Grids

    ERIC Educational Resources Information Center

    Shih, Wen-Chung; Tseng, Shian-Shyong; Yang, Chao-Tung

    2008-01-01

    With the flourishing development of e-Learning, more and more SCORM-compliant teaching materials are developed by institutes and individuals in different sites. In addition, the e-Learning grid is emerging as an infrastructure to enhance traditional e-Learning systems. Therefore, information retrieval schemes supporting SCORM-compliant documents…

  16. Grandfathered, Grandmothered, And ACA-Compliant Health Plans Have Equivalent Premiums.

    PubMed

    Whitmore, Heidi; Gabel, Jon R; Satorius, Jennifer L; Green, Matthew

    2017-02-01

    Many small employers offer employees health plans that are not fully compliant with Affordable Care Act (ACA) provisions such as covering preventive services without cost sharing. These "grandfathered" and "grandmothered" plans accounted for about 65 percent of enrollment in the small-group market in 2014. Premium costs for these and ACA-compliant plans were equivalent.

  17. 48 CFR 9903.201-8 - Compliant accounting changes due to external restructuring activities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... changes due to external restructuring activities. 9903.201-8 Section 9903.201-8 Federal Acquisition... Requirements 9903.201-8 Compliant accounting changes due to external restructuring activities. The contract price and cost adjustment requirements of this part 9903 are not applicable to compliant cost...

  18. Molecular rheological analysis on binary blends of perfluoropolyether lubricants

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  19. Interior, looking northeast Beale Air Force Base, Perimeter Acquisition ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior, looking northeast - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Clean Lubrication Oil Storage Tank & Enclosure, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

  20. Exterior, looking west Beale Air Force Base, Perimeter Acquisition ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Exterior, looking west - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Clean Lubrication Oil Storage Tank & Enclosure, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA