WorldWideScience

Sample records for bearing tests

  1. Bearing/Bypass Material-Testing System

    Science.gov (United States)

    Crews, John H., Jr.

    1988-01-01

    System developed to test specimens in compression as well as tension while maintaining constant bearing/bypass ration. Test specimen with centrally located hole is clamped between two bearing-guide plates using one bolt. Bearing-guide plates then secured to two bearing-load cells. Test specimen independently loaded at both ends, using two separate control systems identified as applied and bypass. If two end loads unequal, difference between them reacted as bolt-bearing load on specimen. Throughout test, two control systems synchronized by common input signal (increasing voltage). As result, loads remain proportional as they increase.

  2. BEARING TESTS FOR THE SPUR TURBOGENERATOR.

    Science.gov (United States)

    The results of the liquid-potassium journalbearing test program for the SPUR turbogenerator are presented. The activities described include the design, assembly and checkout of the bearing test rig, and the results of a successfully completed 250-h endurance test on a hydrodynamic journal bearing using 600 F liquid potassium as the lubricant. Unidirectional loads from 6 to 25 lbs were applied to the bearing operating at a speed of 24,000 rpm. (Author)

  3. Extended Life Testing of Duplex Ball Bearings

    Science.gov (United States)

    Mobley, Jeffrey; Robertson, Michael; Hodges, Charles

    2016-01-01

    Sierra Nevada Corporation’s Space Systems performed bearing life testing for the Scan Mirror Motor/Encoder Assembly (SMMA), part of the Scan Mirror Assembly on-board the Aerosol Polarimetry Sensor (APS) on the NASA Glory Spacecraft. The baseline bearing life test duration extended beyond the launch date for the Glory Spacecraft; a risk that the program was willing to undertake with the understanding that if any anomalies or failures occurred before the required life was achieved, then the mission objectives or operating profile could be modified on orbit to take those results into account. Even though the Glory Spacecraft failed to reach orbit during its launch in March of 2011, the bearing life testing was continued through a mutual understanding of value between Sierra Nevada Corporation and our customer; with a revised goal of testing to failure rather than completing a required number of life cycles. Life testing thus far has not only exceeded the original mission required life, but has also exceeded the published test data for Cumulative Degradation Factor (CDF) from NASA/CR-2009-215681. Many lessons were learned along the way regarding long life testing. The bearing life test has been temporarily suspended due to test support equipment issues.

  4. Numerical simulations of rubber bearing tests and shaking table tests

    International Nuclear Information System (INIS)

    Hirata, K.; Matsuda, A.; Yabana, S.

    2002-01-01

    Test data concerning rubber bearing tests and shaking table tests of base-isolated model conducted by CRIEPI are provided to the participants of Coordinated Research Program (CRP) on 'Intercomparison of Analysis Methods for predicting the behaviour of Seismically Isolated Nuclear Structure', which is organized by International Atomic Energy Agency (IAEA), for the comparison study of numerical simulation of base-isolated structure. In this paper outlines of the test data provided and the numerical simulations of bearing tests and shaking table tests are described. Using computer code ABAQUS, numerical simulations of rubber bearing tests are conducted for NRBs, LRBs (data provided by CRIEPI) and for HDRs (data provided by ENEA/ENEL and KAERI). Several strain energy functions are specified according to the rubber material test corresponding to each rubber bearing. As for lead plug material in LRB, mechanical characteristics are reevaluated and are made use of. Simulation results for these rubber bearings show satisfactory agreement with the test results. Shaking table test conducted by CRIEPI is of a base isolated rigid mass supported by LRB. Acceleration time histories, displacement time histories of the isolators as well as cyclic loading test data of the LRB used for the shaking table test are provided to the participants of the CRP. Simulations of shaking table tests are conducted for this rigid mass, and also for the steel frame model which is conducted by ENEL/ENEA. In the simulation of the rigid mass model test, where LRBs are used, isolators are modeled either by bilinear model or polylinear model. In both cases of modeling of isolators, simulation results show good agreement with the test results. In the case of the steel frame model, where HDRs are used as isolators, bilinear model and polylinear model are also used for modeling isolators. The response of the model is simulated comparatively well in the low frequency range of the floor response, however, in

  5. Design and test of a magnetic thrust bearing

    Science.gov (United States)

    Allaire, P. E.; Mikula, A.; Banerjee, B.; Lewis, D. W.; Imlach, J.

    1993-01-01

    A magnetic thrust bearing can be employed to take thrust loads in rotating machinery. The design and construction of a prototype magnetic thrust bearing for a high load per weight application is described. The theory for the bearing is developed. Fixtures were designed and the bearing was tested for load capacity using a universal testing machine. Various shims were employed to have known gap thicknesses. A comparison of the theory and measured results is presented.

  6. The R and D D's bearing test benches

    International Nuclear Information System (INIS)

    Vialettes, J.M.

    1997-01-01

    In power generation plants, rotating machines are involved in energy transformation processes and safety systems. The bearings supporting the rotors and the thrust bearings play a crucial role in the reliability of these machines. The phenomena encountered straddle several disciplines: hydrodynamics, tribology, thermomechanics, materials and vibrations in a specific environment, namely: thin fluid film, solid mechanical components and shaft rotation. Means of analysing the behaviour of these components (bearings and thrust bearings) have been developed and implemented. These consists of the EDYOS (Etude Dynamique des Organes de Supportage) code for dynamically studying bearing devices and several related bench tests. In reality, in order to understand the complex physical phenomena encountered in these components, it is vital to carry out analyses and experimental validations. Since these investigations cannot be carried out on actual machines, test benches have been built which can subject the sample bearings to the equivalent stresses. (author)

  7. Long-term bearing wear tests of conventional journal bearings and development of hydrostatic bearings for the LOFT drag-disc turbine transducer

    International Nuclear Information System (INIS)

    Fincke, J.R.

    1979-01-01

    The details of a two-year development program concerning materials for use as turbine bearings in a pressurized water reactor environment are reported. Two types of bearings have been examined, both conventional journal bearings and hydrostatic bearings. The results of long-term bearing wear tests conducted at 590 K and 15.1 MPa in water are presented. The feasibility of using hydrostatic bearings for the same transducer is demonstrated

  8. Correlation of elastomer material properties from small specimen tests and scale-size bearing tests

    International Nuclear Information System (INIS)

    Kulak, R.F.; Hughes, T.H.

    1994-01-01

    Tests were performed on small-size elastomer specimens and scale-size laminated elastomeric bearings to correlate the material properties in shear between the two types of tests. An objective of the tests was to see how well the material properties that were determined from specimen tests could predict the response of scale-size laminated elastomeric bearings. Another objective was to compare the results of specimen test and scale-size bearing test conducted by different testing organizations. A comparison between the test results from different organizations on small specimens showed very good agreement. In contrast, the correlation of scale-size bearing tests showed differences in bearing stiffness

  9. Statistical inferences for bearings life using sudden death test

    Directory of Open Access Journals (Sweden)

    Morariu Cristin-Olimpiu

    2017-01-01

    Full Text Available In this paper we propose a calculus method for reliability indicators estimation and a complete statistical inferences for three parameters Weibull distribution of bearings life. Using experimental values regarding the durability of bearings tested on stands by the sudden death tests involves a series of particularities of the estimation using maximum likelihood method and statistical inference accomplishment. The paper detailing these features and also provides an example calculation.

  10. Development and Testing of an Axial Halbach Magnetic Bearing

    Science.gov (United States)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2006-01-01

    The NASA Glenn Research Center has developed and tested a revolutionary Axial Halbach Magnetic Bearing. The objective of this work is to develop a viable non-contact magnetic thrust bearing utilizing Halbach arrays for all-electric flight, and many other applications. This concept will help to reduce harmful emissions, reduce the Nation s dependence on fossil fuels and mitigate many of the concerns and limitations encountered in conventional axial bearings such as bearing wear, leaks, seals and friction loss. The Axial Halbach Magnetic Bearing is inherently stable and requires no active feedback control system or superconductivity as required in many magnetic bearing designs. The Axial Halbach Magnetic Bearing is useful for very high speed applications including turbines, instrumentation, medical systems, computer memory systems, and space power systems such as flywheels. Magnetic fields suspend and support a rotor assembly within a stator. Advanced technologies developed for particle accelerators, and currently under development for maglev trains and rocket launchers, served as the basis for this application. Experimental hardware was successfully designed and developed to validate the basic principles and analyses. The report concludes that the implementation of Axial Halbach Magnetic Bearings can provide significant improvements in rotational system performance and reliability.

  11. Development and Testing of a Radial Halbach Magnetic Bearing

    Science.gov (United States)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2006-01-01

    The NASA John H. Glenn Research Center has developed and tested a revolutionary Radial Halbach Magnetic Bearing. The objective of this work is to develop a viable non-contact magnetic bearing utilizing Halbach arrays for all-electric flight, and many other applications. This concept will help reduce harmful emissions, reduce the Nation s dependence on fossil fuels and mitigate many of the concerns and limitations encountered in conventional axial bearings such as bearing wear, leaks, seals and friction loss. The Radial Halbach Magnetic Bearing is inherently stable and requires no active feedback control system or superconductivity as required in many magnetic bearing designs. The Radial Halbach Magnetic Bearing is useful for very high speed applications including turbines, instrumentation, medical applications, manufacturing equipment, and space power systems such as flywheels. Magnetic fields suspend and support a rotor assembly within a stator. Advanced technologies developed for particle accelerators, and currently under development for maglev trains and rocket launchers, served as the basis for this application. Experimental hardware was successfully designed and developed to validate the basic principles and analyses. The report concludes that the implementation of Radial Halbach Magnetic Bearings can provide significant improvements in rotational system performance and reliability.

  12. Sudden venting test of an emergency bearing for the magnet bearing type compound molecular pump

    International Nuclear Information System (INIS)

    Hiroki, Seiji; Abe, Tetsuya; Murakami, Yoshio; Okamoto, Masatomo; Iguchi, Masashi; Nakamura, Jyunichi; Nakazeki, Tsugito.

    1995-01-01

    The vacuum evacuation system for nuclear fusion reactors bears the role of exhausting hydrogen isotopes in large quantity together with helium continuously for long hours, and as the high vacuum pumps for this purpose, the mechanical pumps which can do continuous evacuation and decrease the quantity of staying radioactive tritium, such as turbo molecular pumps and compound molecular pumps, are promising. Because of the compatibility with tritium, oil lubrication is not desirable, accordingly, the pumps with ceramic rotating vanes and magnetic bearings are demanded. As a part of the development of a magnetic bearing type mechanical pump which can be used for nuclear fusion reactors, the compound molecular pump, in which emergency bearings were incorporated, was made for trial, and the test of sudden air intrusion was carried out, as the results, various knowledges were obtained. The constitution of the testing setup, and the test results are reported. When air was injected at the pressure rise of 3.3x10 4 Pa/s from exhaust port side, after about 2.5 s, the maximum lift of 4.2x10 3 N arose. When air was injected at the pressure rise of 2.7x10 5 Pa/s from the suction part side, after about 0.4s, the maximum lift of 6.9x10 3 N arose. In the air injection alternately from the suction port and exhaust port sides, the emergency bearings functioned normally in 10 times of the test. (K.I.)

  13. Testing N 205 type antifiction bearings in liquid sodium

    International Nuclear Information System (INIS)

    Matal, O.; Handl, Z.

    1976-01-01

    Comprehensive tests were carried out of special N 205 antifriction bearing in liquid, hot sodium at temperatures of 370 degC and 420 degC. Sodium used for tests contained various amounts of oxygen. Visual inspection, X-ray spectral microanalysis, X-ray phase analysis and accurate measurements before and after tests were used to assess the influence of hot aggresive metal. It was found that under the conditions simulated by the tests the ball bearings can be expected to have a short service life. (author)

  14. Standard test method for pin-type bearing test of metallic materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1984-01-01

    1.1 This test method covers a pin-type bearing test of metallic materials to determine bearing yield strength and bearing strength. Note 1—The presence of incidental lubricants on the bearing surfaces may significantly lower the value of bearing yield strength obtained by this method. 1.2 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  15. Innovative Approach to Use Air Bearings in Cubesat Ground Tests

    OpenAIRE

    Gavrilovich, Irina; Krut, Sébastien; Gouttefarde, Marc; Pierrot, François; Dusseau, Laurent

    2016-01-01

    International audience; In the fast-growing society of CubeSat developers, the necessity of CubeSat ground tests is apparent. One of the more complex and discussed system-level tests is the Attitude Determination and Control System (ADCS) examination. It requires motions of the CubeSat and environment conditions close to space. Most of the ADCS testbeds involve an air bearing as one of the main component of a rotating table since it allows reducing the friction between the moving CubeSat and ...

  16. Experimental and Numerical Simulation of Unbalance Response in Vertical Test Rig with Tilting-Pad Bearings

    Directory of Open Access Journals (Sweden)

    Mattias Nässelqvist

    2014-01-01

    Full Text Available In vertically oriented machines with journal bearing, there are no predefined static radial loads, such as dead weight for horizontal rotor. Most of the commercial software is designed to calculate rotordynamic and bearing properties based on machines with a horizontally oriented rotor; that is, the bearing properties are calculated at a static eccentricity. For tilting-pad bearings, there are no existing analytical expressions for bearing parameters and the bearing parameters are dependent on eccentricity and load angle. The objective of this paper is to present a simplified method to perform numerical simulations on vertical rotors including bearing parameters. Instead of recalculating the bearing parameters in each time step polynomials are used to represent the bearing parameters for present eccentricities and load angles. Numerical results are compared with results from tests performed in a test rig. The test rig consists of two guide bearings and a midspan rotor. The guide bearings are 4-pad tilting-pad bearings. Shaft displacement and strains in the bearing bracket are measured to determine the test rig’s properties. The comparison between measurements and simulated results shows small deviations in absolute displacement and load levels, which can be expected due to difficulties in calculating exact bearing parameters.

  17. Numerical simulations of laminated rubber bearing tests and shaking table tests of base-isolated structures

    International Nuclear Information System (INIS)

    1998-01-01

    This report includes the following numerical simulation of rubber bearing tests: Simulation of NRB test (data provided by CRIEPI, Japan); Simulation of LRB test (data provided by CRIEPI, Japan); Simulation of HDR test by (data provided by KAERI, Japan); Simulation of HDR test by (data provided by ENEL, Italy). Numerical simulation of shaking table test for base-isolated steel frame was conducted by ENEL/ISMES/ENEA/EC Numerical simulation of shaking table test for base-isolated rigid mass was conducted by CRIEP1/MIT1

  18. Multiscale characterization of White Etching Cracks (WEC) in a 100Cr6 bearing from a thrust bearing test rig

    DEFF Research Database (Denmark)

    Danielsen, Hilmar Kjartansson; Guzmán, F. Gutiérrez; Dahl, Kristian Vinter

    2017-01-01

    A common cause for premature bearing failures in wind turbine gearboxes are the so-called White Etching Cracks (WEC). These undirected, three-dimensional cracks are bordered by regions of altered microstructure and ultimately lead to a cracking or spalling of the raceway. An accelerated WEC test...... was carried out on a FE8 test rig using cylindrical roller thrust bearings made of martensitic 100Cr6 steel. The resulting WECs were investigated with several characterisation techniques. Ultrasonic measurements showed the WEC were mainly located in the region of the overrolled surface in which negative slip...

  19. The Clouds and the Earth's Radiant Energy System Elevation Bearing Assembly Life Test

    Science.gov (United States)

    Brown, Phillip L.; Miller, James B.; Jones, William R., Jr.; Rasmussen, Kent; Wheeler, Donald R.; Rana, Mauro; Peri, Frank

    1999-01-01

    The Clouds and the Earth's Radiant Energy System (CERES) elevation scan bearings lubricated with Pennzane SHF X2000 and 2% lead naphthenate (PbNp) were life tested for a seven-year equivalent Low Earth Orbit (LEO) operation. The bearing life assembly was tested continuously at an accelerated and normal rate using the scanning patterns developed for the CERES Earth Observing System AM-1 mission. A post-life-test analysis was performed on the collected data, bearing wear, and lubricant behavior.

  20. High-Speed Shaft Bearing Loads Testing and Modeling in the NREL Gearbox Reliability Collaborative: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    McNiff, B.; Guo, Y.; Keller, J.; Sethuraman, L.

    2014-12-01

    Bearing failures in the high speed output stage of the gearbox are plaguing the wind turbine industry. Accordingly, the National Renewable Energy Laboratory (NREL) Gearbox Reliability Collaborative (GRC) has performed an experimental and theoretical investigation of loads within these bearings. The purpose of this paper is to describe the instrumentation, calibrations, data post-processing and initial results from this testing and modeling effort. Measured HSS torque, bending, and bearing loads are related to model predictions. Of additional interest is examining if the shaft measurements can be simply related to bearing load measurements, eliminating the need for invasive modifications of the bearing races for such instrumentation.

  1. Design and evaluation of a 3 million DN series-hybrid thrust bearing. [stability tests and fatigue tests

    Science.gov (United States)

    Scibbe, H. W.; Winn, L. W.; Eusepi, M.

    1976-01-01

    The bearing, consisting of a 150-mm ball bearing and a centrifugally actuated, conical, fluid-film bearing, was fatigue tested. Test conditions were representative of a mainshaft ball bearing in a gas turbine engine operating at maximum thrust load to simulate aircraft takeoff conditions. Tests were conducted up to 16000 rpm and at this speed an axial load of 15568 newtons (3500 lb) was safely supported by the hybrid bearing system. Through the series-hybrid bearing principle, the effective ball bearing speed was reduced to approximately one-half of the shaft speed. It was concluded that a speed reduction of this magnitude results in a ten-fold increase in the ball bearing fatigue life. A successful evaluation of fluid-film bearing lubricant supply failure was performed repeatedly at an operating speed of 10,000 rpm. A complete and smooth changeover to full-scale ball bearing operation was effected when the oil supply to the fluid-film bearing was cut off. Reactivation of the fluid-film oil supply system resulted in a flawless return to the original mode of hybrid operation.

  2. Summary of experimental tests of elastomeric seismic isolation bearings for use in nuclear reactor plants

    International Nuclear Information System (INIS)

    Seidensticker, R.W.; Chang, Y.W.; Kulak, R.F.

    1992-01-01

    This paper describes an experimental test program for isolator bearings which was developed to help establish the viability of using laminated elastomer bearings for base isolation of nuclear reactor plants. The goal of the test program is to determine the performance characteristics of laminated seismic isolation bearings under a wide range of loadings. Tests were performed on scale-size laminated seismic isolators both within the design shear strain range to determine the response of the bearing under expected earthquake loading conditions, and beyond the design range to determine failure modes and to establish safety margins. Three types of bearings, each produced from a different manufacturer, have been tested: (1) high shape factor-high damping-high shear modulus bearings; (2) medium shape factor-high damping-high shear modulus bearings; and (3) medium shape factor-high damping-low shear modulus bearings. All of these tests described in this report were performed at the Earthquake Engineering Research Center at the University of California, Berkeley, with technical assistance from ANL. The tests performed on the three types of bearings have confirmed the high performance characteristics of the high damping-high and low shear modulus elastomeric bearings. The bearings have shown that they are capable of having extremely large shear strains before failure occurs. The most common failure mechanism was the debonding of the top steel plate from the isolators. This failure mechanism can be virtually eliminated by improved manufacturing quality control. The most important result of the failure test of the isolators is the fact that bearings can sustain large horizontal displacement, several times larger than the design value, with failure. Their performance in moderate and strong earthquakes will be far superior to conventional structures

  3. History of Space Shuttle Main Engine Turbopump Bearing Testing at the Marshall Space Flight Center

    Science.gov (United States)

    Gibson, Howard; Thom, Robert; Moore, Chip; Haluck, Dave

    2010-01-01

    The Space Shuttle is propelled into orbit by two solid rocket motors and three liquid fed main engines. After the solid motors fall away, the shuttle engines continue to run for a total time of 8 minutes. These engines are fed propellants by low and high pressure turbopumps. A critical part of the turbopump is the main shaft that supports the drive turbine and the pump inducer and impeller. Rolling element bearings hold the shaft in place during rotation. If the bearings were to fail, the shaft would move, allowing components to rub in a liquid oxygen or hydrogen environment, which could have catastrophic results. These bearings are required to spin at very high speeds, support radial and axial loads, and have high wear resistance without the benefit of a conventional means of lubrication. The Rocketdyne built Shuttle turbopumps demonstrated their capability to perform during launches; however, the seven hour life requirement was not being met. One of the limiting factors was the bearings. In the late 1970's, an engineering team was formed at the Marshall Space Flight Center (MSFC), to develop a test rig and plan for testing the Shuttle s main engine high pressure oxygen turbopump (HPOTP) bearings. The goals of the program were to better understand the operation of bearings in a cryogenic environment and to further develop and refine existing computer models used to predict the operational limits of these bearings. In 1982, testing began in a rig named the Bearing and Seal Material Tester or BSMT as it was commonly called. The first testing investigated the thermal margin and thermal runaway limits of the HPOTP bearings. The test rig was later used to explore potential bearing improvements in the area of increased race curvatures, new cage materials for better lubrication, new wear resistant rolling element materials, and other ideas to improve wear life. The most notable improvements during this tester s time was the incorporation of silicon nitride balls and

  4. Dynamic Performance Characteristic Tests of Real Scale Lead Rubber Bearing for the Evaluation of Performance Criteria

    International Nuclear Information System (INIS)

    Kim, Min Kyu; Kim, Jung-Han; Choi, In-Kil

    2014-01-01

    Dynamic characteristic tests of full scale lead rubber bearing were performed for the evaluation of performance criteria of isolation system for nuclear power plants. For the dynamic test for a full scale rubber bearing, two 1500mm diameter lead rubber bearings were manufactured. The viewpoints of this dynamic test are determination of an ultimate shear strain level of lead rubber bearing, behavior of rubber bearing according to static and dynamic input motion, sinusoidal and random (earthquake) motion, and 1-dimentional and 2-dimensional input motion. In this study, seismic isolation device tests were performed for the evaluation of performance criteria of isolation system. Through this test, it can be recognized that in the case of considering a mechanical property test, dynamic and multi degree of loading conditions should be determined. But these differences should be examined how much affect to the global structural behavior

  5. The analysis, design, and testing of a blood lubricated hydrodynamic journal bearing.

    Science.gov (United States)

    Walowit, J A; Malanoski, S B; Horvath, D; Golding, L R; Smith, W A

    1997-01-01

    The Cleveland Clinic Foundation's Innovative Ventricular Assist System (IVAS) uses a hydrodynamic journal bearing to support the rotating assembly of the blood pump. Bearing dimensions are chosen so that a stable film of lubricant develops and separates stationary and rotating pump surfaces during operation. This bearing type provides several advantages for a permanently implanted device, including essentially no wear for very long life and very high reliability, as well as a self pumping action that generates circumferential wash flow and thus lowers the risk of bearing associated deposition. However, these advantages are accompanied by design issues not encountered with typical journal bearing, such as low shear stress, bearing ends that are not at atmospheric pressure, and low radial bearing loads. To address these issues, several concepts for a hydrodynamic blood bearing were designed and analyzed using a special computer code to perform parametric studies. This design analysis code was developed to define optimum bearing performance under selected load and speed ranges and within practical tolerances. Results showed the range of dimensions and conditions over which an effective, reliable, blood lubricated journal bearing can be designed. Subsequent bench testing has validated the theoretical conclusions and shown this bearing type to be very robust in a blood pump application.

  6. The Effect of Computerized Testing on Sun Bear Behavior and Enrichment Preferences

    OpenAIRE

    Perdue, Bonnie M.

    2016-01-01

    The field of comparative cognition investigates species’ differences and similarities in cognitive abilities, and sheds light on the evolutionary origins of such capacities. Cognitive testing has been carried out in a variety of species; however, there are some taxa that are underrepresented in this field. The current work follows on a recent increase in cognitive research in the order Carnivora with a specific focus on sun bears. Sun bears are the smallest existing bear species and live in t...

  7. Oil-Free Turbomachinery Research Enhanced by Thrust Bearing Test Capability

    Science.gov (United States)

    Bauman, Steven W.

    2003-01-01

    NASA Glenn Research Center s Oil-Free Turbomachinery research team is developing aircraft turbine engines that will not require an oil lubrication system. Oil systems are required today to lubricate rolling-element bearings used by the turbine and fan shafts. For the Oil-Free Turbomachinery concept, researchers combined the most advanced foil (air) bearings from industry with NASA-developed high-temperature solid lubricant technology. In 1999, the world s first Oil-Free turbocharger was demonstrated using these technologies. Now we are working with industry to demonstrate Oil-Free turbomachinery technology in a small business jet engine, the EJ-22 produced by Williams International and developed during Glenn s recently concluded General Aviation Propulsion (GAP) program. Eliminating the oil system in this engine will make it simpler, lighter (approximately 15 percent), more reliable, and less costly to purchase and maintain. Propulsion gas turbines will place high demands on foil air bearings, especially the thrust bearings. Up until now, the Oil-Free Turbomachinery research team only had the capability to test radial, journal bearings. This research has resulted in major improvements in the bearings performance, but journal bearings are cylindrical, and can only support radial shaft loads. To counteract axial thrust loads, thrust foil bearings, which are disk shaped, are required. Since relatively little research has been conducted on thrust foil air bearings, their performance lags behind that of journal bearings.

  8. Testing of full scale composite journal bearings for offshore underwater applications

    NARCIS (Netherlands)

    Dragt, R.C.; Van Den Heuvel, W.; Gelinck, E.R.M.; Slot, H.M.

    2015-01-01

    In the offshore industry, fibre reinforced sliding journal bearings are increasingly used due to their low-maintenance and self-lubricating characteristics. To be able to use the bearings in the rough offshore environment, under heavy loading, full scale tests are essential to assess the friction

  9. The Effect of Computerized Testing on Sun Bear Behavior and Enrichment Preferences.

    Science.gov (United States)

    Perdue, Bonnie M

    2016-09-22

    The field of comparative cognition investigates species' differences and similarities in cognitive abilities, and sheds light on the evolutionary origins of such capacities. Cognitive testing has been carried out in a variety of species; however, there are some taxa that are underrepresented in this field. The current work follows on a recent increase in cognitive research in the order Carnivora with a specific focus on sun bears. Sun bears are the smallest existing bear species and live in tropical regions of Southeast Asia. They have an omnivorous diet and use their tongues to forage for insects and sap. Little is known about sun bear cognition, although much like other bear species, anecdotes suggest a high level of intelligence. The current work explored training sun bears to use a touchscreen computer. This effort allows for insight into cognitive abilities as well as providing a complex source of enrichment for the bears. The bears use their tongues to respond to a touchscreen computer, and the effects on stereotypic behaviors on exhibit and preference for this over other forms of enrichment were examined. Overall, bears performed well on the task and showed a preference for the computer.

  10. The Effect of Computerized Testing on Sun Bear Behavior and Enrichment Preferences

    Directory of Open Access Journals (Sweden)

    Bonnie M. Perdue

    2016-09-01

    Full Text Available The field of comparative cognition investigates species’ differences and similarities in cognitive abilities, and sheds light on the evolutionary origins of such capacities. Cognitive testing has been carried out in a variety of species; however, there are some taxa that are underrepresented in this field. The current work follows on a recent increase in cognitive research in the order Carnivora with a specific focus on sun bears. Sun bears are the smallest existing bear species and live in tropical regions of Southeast Asia. They have an omnivorous diet and use their tongues to forage for insects and sap. Little is known about sun bear cognition, although much like other bear species, anecdotes suggest a high level of intelligence. The current work explored training sun bears to use a touchscreen computer. This effort allows for insight into cognitive abilities as well as providing a complex source of enrichment for the bears. The bears use their tongues to respond to a touchscreen computer, and the effects on stereotypic behaviors on exhibit and preference for this over other forms of enrichment were examined. Overall, bears performed well on the task and showed a preference for the computer.

  11. Hotfire testing of a SSME HPOTP with an annular hydrostatic bearing

    Science.gov (United States)

    Nolan, Steven A.; Hibbs, Robert I.; Genge, Gary G.

    1994-01-01

    A new fluid film bearing package has been tested in the Space Shuttle Main Engine (SSME) High Pressure Oxygen Turbopump (HPOTP). This fluid film element functions as both the pump end bearing and the preburner pump rear wear ring seal. Most importantly, it replaces a duplex ball bearing package which has been the primary life limiting component in the turbopump. The design and predicted performance of the turbopump are reviewed. Results are presented for measured pump and bearing performance during testing on the NASA Technology Test Bed (TTB) Engine located at MSFC. The most significant results were obtained from proximity probes located in the bearing bore which revealed large subsynchronous precession at ten percent of shaft speed during engine start which subsided prior to mainstage power levels and reappeared during engine shutdown at equivalent power levels below 65% of nominal. This phenomenon has been attributed to rotating stall in the diffuser. The proximity probes also revealed the location of the bearing in the bore for different operating speeds. Pump vibration characteristics were improved as compared to pumps tested with ball bearings. After seven starts and more than 700 seconds of testing, the pump showed no signs of performance degradation.

  12. The design, manufacture and testing of the hydrostatic bearing for the NSF 900 analysing magnet

    International Nuclear Information System (INIS)

    Acton, W.J.; Myers, D.B.

    1978-10-01

    This report describes the design, manufacture and testing of the hydrostatic bearing which will be used to support the 90 0 analysing magnet of the 30 MV tandem electrostatic accelerator now being constructed at Daresbury Lboratory. (author)

  13. 'GRC1.5': Uptower Gearbox Testing to Investigate Bearing Axial Cracking

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jonathan; Vaes, David; McNiff, Brian

    2016-02-16

    This presentation focuses on the investigation of bearing axial cracking using the GRC1.5 uptower gearbox. Topics covered include the testing options considered, the project goal, and current and near-term activities.

  14. Evaluation of axial pile bearing capacity based on pile driving analyzer (PDA) test using Neural Network

    Science.gov (United States)

    Maizir, H.; Suryanita, R.

    2018-01-01

    A few decades, many methods have been developed to predict and evaluate the bearing capacity of driven piles. The problem of the predicting and assessing the bearing capacity of the pile is very complicated and not yet established, different soil testing and evaluation produce a widely different solution. However, the most important thing is to determine methods used to predict and evaluate the bearing capacity of the pile to the required degree of accuracy and consistency value. Accurate prediction and evaluation of axial bearing capacity depend on some variables, such as the type of soil, diameter, and length of pile, etc. The aims of the study of Artificial Neural Networks (ANNs) are utilized to obtain more accurate and consistent axial bearing capacity of a driven pile. ANNs can be described as mapping an input to the target output data. The method using the ANN model developed to predict and evaluate the axial bearing capacity of the pile based on the pile driving analyzer (PDA) test data for more than 200 selected data. The results of the predictions obtained by the ANN model and the PDA test were then compared. This research as the neural network models give a right prediction and evaluation of the axial bearing capacity of piles using neural networks.

  15. Experimental test of static and dynamic characteristics of tilting-pad thrust bearings

    Directory of Open Access Journals (Sweden)

    Annan Guo

    2015-07-01

    Full Text Available The axial vibration in turbine machine has attracted more and more interest. Tilting-pad thrust bearings are widely used in turbine machines to support the axial load. The dynamic properties generated by oil film of the thrust pad have important effects on the axial vibration of the rotor-bearing system. It is necessary to develop the method to test the dynamic characteristics of thrust bearings. A new rig has been developed. The facility allows a complete set of bearing operating parameters to be measured. Parameters measured include oil temperatures, oil-film thickness, and pressure. The static load and dynamic load can be added on the thrust bearing in the vertical direction at the same time. The relative and absolute displacement vibrations of the test experimental bearing with the changes of dynamic force are measured, and the dynamic characteristics of the test bearing are obtained. The experimental results show clearly that the operating conditions influence largely on the pad static and dynamic characteristics.

  16. A test apparatus and facility to identify the rotordynamic coefficients of high-speed hydrostatic bearings

    Science.gov (United States)

    Childs, Dara; Hale, Keith

    1994-01-01

    A facility and apparatus are described which determine stiffness, damping, and added-mass rotordynamic coefficients plus steady-state operating characteristics of high speed hydrostatic journal bearings. The apparatus has a current top speed of 29,800 rpm with a bearing diameter of 7.62 cm (3 in.). Purified warm water, 55 C (130 F), is used as a test fluid to achieve elevated Reynolds numbers during operation. The test-fluid pump yields a bearing maximum inlet pressure of 6.9 Mpa (1000 psi). Static load on the bearing is independently controlled and measured. Orthogonally mounted external shakers are used to excite the test stator in the direction of, and perpendicular to, the static load. The apparatus can independently calculate all rotordynamic coefficients at a given operating condition.

  17. Damage Equivalent Test Methodologies as Design Elements for Journal Bearing Systems

    Directory of Open Access Journals (Sweden)

    Florian Summer

    2017-12-01

    Full Text Available The current paper addresses the field of experimental research of journal bearing systems. In this regard, the challenges are dealt with concerning simultaneous testing with a close correlation to the industrial application and with a high resolution of tribological processes. Concerning this aspect, two damage equivalent laboratory test methodologies for journal slide bearing systems are presented, and their ability to visualize certain performance parameters of bearing systems are emphasized (for instance friction performance, (start stop wear processes, and seizure events. The results clearly emphasize that the applied methodologies provide accurate findings regarding specific effects of selective parameters/changes on the performance of bearing systems, such as polymer overlays may result in improved mixed friction sliding conditions if designed properly, and they provide superior start stop wear resistance; the use of specific corrosion inhibitors can successfully prevent tribo-corrosion on bronze bearings; a decrease of oil viscosity increases solid friction share but decreases fluid friction; lubricant anti-wear additives are able to improve seizure resistance and sliding properties of bearing systems depending on formulation harmonization; and novel bearing material coatings, e.g., sputtered SnCu, can significantly improve emergency running capabilities.

  18. Performance of Small Bore 60NiTi Hybrid Ball Bearings: Preliminary Life Test Results

    Science.gov (United States)

    Dellacorte, Christopher; Howard, S. Adam

    2016-01-01

    Small bore (R8 size) hybrid ball bearings made with 60NiTi races and silicon nitride balls are under development for highly corrosive aerospace applications that are also exposed to heavy static (shock) loads. The target application is the vacuum pump used inside the wastewater recycling system on the International Space Station. To verify bearing longevity, life tests are run at 2000rpm for time periods up to 5000 hours. Accelerometers with data tracking are used to monitor operation and the bearings are disassembled and inspected at intervals to assess wear. Preliminary tests show that bearings made from 60NiTi are feasible for this aerospace and potentially other industrial applications that must endure similar operating environments.

  19. Accelerated Testing of UH-60 Viscous Bearings for Degraded Grease Fault

    Science.gov (United States)

    Dykas, Brian; Hood, Adrian; Krantz, Timothy; Klemmer, Marko

    2015-01-01

    An accelerated aging investigation of critical aviation bearings lubricated with MIL-PRF- 81322 grease was conducted to derive an understanding of the mechanisms of grease degradation and loss of lubrication over time. The current study focuses on UH-60 Black Hawk viscous damper bearings supporting the tail rotor driveshaft, which were subjected to more than 5800 hours of testing in a heated environment to accelerate the deterioration of the grease. The mechanism of grease degradation is a reduction in the oil/thickener ratio rather than the expected chemical degradation of grease constituents. Over the course of testing, vibration and temperature monitoring of bearings was conducted and trends for failing bearings are presented.

  20. Regressive approach for predicting bearing capacity of bored piles from cone penetration test data

    Directory of Open Access Journals (Sweden)

    Iyad S. Alkroosh

    2015-10-01

    Full Text Available In this study, the least square support vector machine (LSSVM algorithm was applied to predicting the bearing capacity of bored piles embedded in sand and mixed soils. Pile geometry and cone penetration test (CPT results were used as input variables for prediction of pile bearing capacity. The data used were collected from the existing literature and consisted of 50 case records. The application of LSSVM was carried out by dividing the data into three sets: a training set for learning the problem and obtaining a relationship between input variables and pile bearing capacity, and testing and validation sets for evaluation of the predictive and generalization ability of the obtained relationship. The predictions of pile bearing capacity by LSSVM were evaluated by comparing with experimental data and with those by traditional CPT-based methods and the gene expression programming (GEP model. It was found that the LSSVM performs well with coefficient of determination, mean, and standard deviation equivalent to 0.99, 1.03, and 0.08, respectively, for the testing set, and 1, 1.04, and 0.11, respectively, for the validation set. The low values of the calculated mean squared error and mean absolute error indicated that the LSSVM was accurate in predicting the pile bearing capacity. The results of comparison also showed that the proposed algorithm predicted the pile bearing capacity more accurately than the traditional methods including the GEP model.

  1. Working Vibration Analysis of the Bearing Plate on Roadheader Test Bed

    Directory of Open Access Journals (Sweden)

    Liu Yi

    2015-01-01

    Full Text Available In order to research the vibration characteristics of the bearing plate on roadheader test bed to bear the roadheaders with different parameters, this paper establishes a multi-body dynamic model for the bearing plate to bear the roadheaders by using the theory of multi-body dynamics, and analyzes and determines a mathematical model of loads between the track and the bearing plate. By modal analysis of multi-body dynamic model of the roadheader, this paper extracts the modal shape of the system, and draws a frequency response diagram for system vibration, and obtains a larger vibration frequency range. To further explore the vibration characteristics, this paper researches the damping of different hydraulic systems, different mass, stiffness parameters and the impact of the roadheader on the vibration of the bearing plate on the test bed by using the computer numerical simulation, and obtains the longitudinal vibration characteristics of three test points in the geometric center, namely, cutting head, cantilever and engine body. The research results show that the mass of the road-header on the test bed is increased by 6%, and the longitudinal amplitudes of the cutting head and cantilever are respectively reduced by 37% and 19%; the damping of the hydraulic system of the roadheader is increased by 19%, and the longitudinal amplitudes of the cutting head, cantilever and engine body are respectively reduced by 33%, 23% and 16%; the stiffness of the engine body doubles, and the longitudinal amplitudes of the cutting head and cantilever are respectively reduced by 35.8% and 27%. The results are consistent with the underground industrial test so as to provide a regularity basis for load analysis of the test bed bearing the roadheaders with different parameters.

  2. State of art report for high temperature wear test of SMART MCP and CEDM bearing material

    International Nuclear Information System (INIS)

    Cho, Yong Hu; Lee, Jae Seon; Park, Jin Seok; Kim, Ji Ho; Kim, Jong In

    2000-03-01

    Wear resistance properties of machine elements has been more critical in view of its significant effect on life extension, economics and material saving because it has been recognized that nearly 80 percent of damages of mechanical elements in the friction pairs are due to the material loss by wear. And wear properties have direct influence on the life of a machine in a great extend under extremely severe operating condition. Therefore highly improved wear properties of machine elements operating in such circumstances is heavily required. The purpose of this report is to survey current technology for high temperature wear test in order to establish the test plan for the life evaluation of SMART MCP and CEDM bearing materials. Friction and wear test will be done under high pressure (170 MPa) and high temperature (350 degree C) with water as lubricant to simulate the operating condition of the nuclear power reactor. Because pump type for MCP is selected as the caned motor pump which needs no mechanical sealing, the rotating shaft on which bearing is fully submerged by main coolant with high temperature. So MCP bearing operates without additional lubricant. CEDM is adopted as the ball-screw type with fine controllability. So the driving part is designed as the immersed-in type by main coolant. Therefore the anti-wear and reliability of driving parts are much consequent to guarantee the lifetime and the safety of the whole system. Tribometer adapted to high temperature and pressure circumstance is needed to execute bearing material testing. Test parameters are material, sliding speed, sliding distance and applied load. In order to identify the wear mechanism, optical microscope and surface roughness testers are required. The result of this report will provide an elementary data to develop bearing materials and to estimate bearing lifetime for the bearings of MCP and CEDM in SMART. (author)

  3. Investigation of Bearing Axial Cracking: Benchtop and Full-Scale Test Results

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jonathan A. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gould, Benjamin [Argonne National Lab. (ANL), Argonne, IL (United States); Greco, Aaron [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-08-16

    The most common failure mode in wind turbine gearboxes is axial cracking in intermediate and high-speed-stage bearings, also commonly called white-etching cracks (WECs). Although these types of cracks have been reported for over a decade, the conditions leading to WECs, the process by which this failure culminates, and the reasons for their apparent prevalence in wind turbine gearboxes are all highly debated. This paper summarizes the state of a multipronged research effort to examine the causes of WECs in wind turbine gearbox bearings. Recent efforts have recreated WECs on a benchtop test rig in highly loaded sliding conditions, wherein it was found that the formation of a dark etching microstructure precedes the formation of a crack, and a crack precedes the formation of white-etching microstructure. A cumulative frictional sliding energy criterion has been postulated to predict the presence of WECs. Bearing loads have also been measured and predicted in steady state and transient drivetrain operations in dynamometer testing. In addition, both loads and sliding at full scale will be measured in planned uptower drivetrain testing. If the cumulative frictional sliding energy is the dominant mechanism that causes WECs, understanding the amount of frictional sliding energy that wind turbine bearings are subjected to in typical operations is the next step in the investigation. If highly loaded sliding conditions are found uptower, similar to the examined benchtop levels, appropriate mitigation solutions can be examined, ranging from new bearing coatings and improved lubricants to changes in gearbox designs and turbine operations.

  4. Accelerated Bearing Life-time Test Rig Development for Low Speed Data Acquisition

    Directory of Open Access Journals (Sweden)

    Andreas Klausen

    2017-07-01

    Full Text Available Condition monitoring plays an important role in rotating machinery to ensure reliability of the equipment, and to detect fault conditions at an early stage. Although health monitoring methodologies have been thoroughly developed for rotating machinery, low-speed conditions often pose a challenge due to the low signal-to-noise ratio. To this aim, sophisticated algorithms that reduce noise and highlight the bearing faults are necessary to accurately diagnose machines undergoing this condition. In the development phase, sensor data from a healthy and damaged bearing rotating at low-speed is required to verify the performance of such algorithms. A test rig for performing accelerated life-time testing of small rolling element bearings is designed to collect necessary sensor data. Heavy loads at high-speed conditions are applied to the test bearing to wear it out fast. Sensor data is collected in intervals during the test to capture the degeneration features. The main objective of this paper is to provide a detailed overview for the development and analysis of this test rig. A case study with experimental vibration data is also presented to illustrate the efficacy of the developed test rig.

  5. Development testing of high temperature bearings for SP-100 control drive assemblies

    Science.gov (United States)

    Dalcher, Alfred W.; Kjaer-Olsen, Christian G.; Martinez, Carlos; Ogawa, Stanley Y.; Springer, Dwight R.; Yaspo, Robert

    1992-01-01

    Initial phases of two distinct SP-100 control drive assembly bearing test programs were successfully completed at elevated temperature in vacuum. The first was for the reflector drive line spherical self-aligning bearings. Each bearing consisted of a carbon-graphite ball mounted on an aluminum oxide-coated Ta-10%W shaft, captured by an aluminum oxide-coated Ta-10%W socket. One set of these bearings was exposed to temperatures up to 1180K (1665°F) at 1.33×10-6 Pa (1×10-8 torr) and subjected to 38000 cycles of motion. Friction coefficients were found to be between 0.11 and 0.25 over the full range of operation. Overall performance of the bearings was excellent, with only slight wear observed. The second test program was for the safety rod slider bearing. Zirconium carbide coated Nb-1%Zr bearings pads were stroked inside a molybdenum tube at temperatures up to 1422 K (2100°F) at ˜1.33×10-6 Pa with a normal load of 1.02 Kg between each sliding surface. Coefficients of sliding friction were found to increase from 0.90 at 293 K to 1.20 at 1422 K prior to high temperature dwells. Results were consistent over the range of stroke velocities; 5.1 to 51 mm (0.2 to 2.0 inches) per second. Following dwells of 92, 72, and 110 hours at 1422 K, static friction coefficients as high as 5.4 were observed prior to initiation of sliding, after which sliding friction coefficients of ˜1.6 were seen. Breakaway forces were well within the actuator design limits.

  6. A numerical test method of California bearing ratio on graded crushed rocks using particle flow modeling

    OpenAIRE

    Jiang, Yingjun; Wong, Louis Ngai Yuen; Ren, Jiaolong

    2015-01-01

    In order to better understand the mechanical properties of graded crushed rocks (GCRs) and to optimize the relevant design, a numerical test method based on the particle flow modeling technique PFC2D is developed for the California bearing ratio (CBR) test on GCRs. The effects of different testing conditions and micro-mechanical parameters used in the model on the CBR numerical results have been systematically studied. The reliability of the numerical technique is verified. The numerical resu...

  7. Temperature Distribution Simulation of a Polymer Bearing Basing on the Real Tribological Tests

    Directory of Open Access Journals (Sweden)

    Artur Król

    2015-09-01

    Full Text Available Polymer bearings are widely used due to dry-lubrication mechanism, low weight, corrosion resistance and free maintenance. They are applied in different tribological pairs, i.e. household appliances, mechatronics systems, medical devices, food machines and many more. However their use is limited by high coefficient of thermal expansion and softening at elevated temperature, especially when working outside recommended pv factors. The modification of bearing design to achieve better characteristics at more demanding conditions, requires full understanding of mechanical and thermal phenomena of bearing work. The first step was to observe a thermal behavior of polymer bearing under real test conditions (50, 100, 150 rpm and 350 and 700N until constant values were achieved, i.e. temperature and moment of friction. Subsequently collected data were used in a design of temperature distribution model. Thermal simulations of the polymer bearing were done using commercial software package ANSYS Fluent, which is based on finite volume method. All calculations were performed for 3D geometrical model that included polymer bearing, its housing, shaft and some volume of the surrounding air. The heat generation caused by friction forces was implemented by volumetric heat source. All three main heat transfer mechanism (conduction, convection and radiation were included in heat transfer calculations and the air flow around the bearing and adjacent parts was directly solved. The unknown parameters of the numerical model were adjusted by comparison of the results from computer calculations with the measured temperature rise. In the presented work the calculations were limited to steady state conditions only, but the model may be also used in transient analysis.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7342

  8. Mechanical testing of high-damping elastomer materials for determining design parameters of seismic isolation bearings

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, T.H.; Kulak, R.F.

    1994-06-01

    High-damping steel-laminated elastomeric bearings are one of the devices used for isolating large buildings and structures from earthquake damage. These load-bearing isolators are constructed from alternating layers of high-damping rubber and steel plates. In this paper the mechanical testing of small specimens of some elastomer compounds proposed for the isolation of advanced nuclear reactors is discussed. Variation of shear stiffness and damping with respect to shear strain level (5 % to 300 %), temperature ({minus}40{degrees}C to +50{degrees}C) and frequency (0.002Hz to 5Hz) are reported. Problems involved in obtaining reliable and repeatable results are also discussed.

  9. Effect of mixing geopolymer and peat on bearing capacity in Ogan Komering Ilir (OKI) by California bearing ratio (CBR) test

    Science.gov (United States)

    Raharja, Danang S.; Hadiwardoyo, Sigit P.; Rahayu, Wiwik; Zain, Nasuhi

    2017-06-01

    Geopolymer is binder material that consists of solid material and the activator solution. Geopolymer material has successfully replaced cement in the manufacture of concrete with aluminosilicate bonding system. Geopolymer concrete has properties similar to cement concrete with high compressive strength, low shrinkage value, relatively low creep value, as well as acid-resistant. Based on these, the addition of polymers in peat soils is expected to improve the bearing capacity of peat soils. A study on the influence of geopolymer addition in peat soils was done by comparing before and after the peat soil was mixed with geopolymer using CBR (California Bearing Ratio) test in unsoaked and soaked conditions. 10% mixture content of the peat dry was used, weighted with a variety of curing time 4 hours, 5 days, and 10 days. There were two methods of mixing: first, peat was mixed with fly ash geopolymer activators and mixed solution (waterglass, NaOH, water), and second, peat was mixed with fly ash and mixed geopolymer (waterglass, NaOH, water, fly ash). Changes were observed in specific gravity, dry density, acidity (pH), and the microscopic structure with Scanning Electron Microscope (SEM). Curing time did not significantly affect the CBR value. It even shows a tendency to decline with longer curing time. The first type mixture obtained CBR value of: 5.4% for 4 hours curing, 4.6% for 5 days curing and 3.6% for 10 days curing. The second type mixture obtained CBR value of: 6.1% for 4 hours curing, 5.2% for 5 days curing and 5.2% for 10 days curing. Furthermore, the specific gravity value, dry density, pH near neutral and swelling percentage increased. From both variants, the second type mixture shows better results than the first type mixture. The results of SEM (Scanning Electron Microscopy) show the structure of the peat which became denser with the fly ash particles filling the peat microporous. Also, the reaction of fly ash with geopolymer is indicated by the solid

  10. Evaluation of a series hybrid thrust bearing at DN values to three million. 2: Fabrication and testing

    Science.gov (United States)

    Eusepi, M.; Winn, L. W.

    1975-01-01

    Results of tests made to determine the experimental performance of a series hybrid bearing are reported. The bearing consists of a 150 mm ball bearing and a centrifugally actuated, conical, fluid film bearing fitting an envelope with an outer radius of 86.4 mm (3.4 in.) and inner radius of 71 mm (2.8 in.). Tests were conducted up to 16,500 rpm, at which speed an axial load of 15,568 N (3500 lb) was safely supported by the hybrid bearing system. Through the employment of the series hybrid bearing principle, it was possible to reduce the effective ball bearing speed to approximately one-half of the shaft speed. A reduction of this magnitude should result in a tenfold increase in the ball bearing fatigue life. A successful simulation of fluid film bearing lubricant supply failure, performed repeatedly at an operating speed of 10,000 rpm, resulted in complete and smooth change over to full scale ball bearing operation when the oil supply to the fluid film bearing was discontinued. Reactivation of the fluid film supply system produced a flawless return to the original mode of hybrid operation.

  11. Equipment for accelerated tests of bearings for reactor control system linear electromagnet drives

    International Nuclear Information System (INIS)

    Voskobojnikov, V.V.; Semchenko, Eh.L.; Usov, P.P.; Nikolaev, V.P.

    1989-01-01

    Specific operation of friction units in reactor control system linear electromagnet drives is considered. Installation for determining specific electromagnetic forces, applied to bearings of reactor control system drives, and equipment for wear tests of friction pairs are described. The considered equipment permits to study characteristics of promising materials of friction pairs, to determine their wear resistance and operating longevity, that much reduces tests cost and time

  12. The R and D D`s bearing test benches; Les bancs d`essais de paliers de la DER

    Energy Technology Data Exchange (ETDEWEB)

    Vialettes, J.M. [Service Ensembles de Production, Departement Machines, Direction des Etudes et Recherches, Electricite de France (EDF), 92 - Clamart (France)

    1997-01-01

    In power generation plants, rotating machines are involved in energy transformation processes and safety systems. The bearings supporting the rotors and the thrust bearings play a crucial role in the reliability of these machines. The phenomena encountered straddle several disciplines: hydrodynamics, tribology, thermomechanics, materials and vibrations in a specific environment, namely: thin fluid film, solid mechanical components and shaft rotation. Means of analysing the behaviour of these components (bearings and thrust bearings) have been developed and implemented. These consists of the EDYOS (Etude Dynamique des Organes de Supportage) code for dynamically studying bearing devices and several related bench tests. In reality, in order to understand the complex physical phenomena encountered in these components, it is vital to carry out analyses and experimental validations. Since these investigations cannot be carried out on actual machines, test benches have been built which can subject the sample bearings to the equivalent stresses. (author) 14 figs.

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

    Science.gov (United States)

    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. STUDIES OF BASIC BEARING DESIGNS FOR AN ADVANCED GYRO TEST TURNTABLE.

    Science.gov (United States)

    pair of opposing-thrust air bearings, an eight-pad oil journal bearing , and an eight-pad air journal bearing . In addition to solving for flow, film...thickness and stiffness, a detailed analysis of the load capabilities of the oil journal bearing is carried out, as well as an optimization of the

  15. The increase in cobalt release in metal-on-polyethylene hip bearings in tests with third body abrasives.

    Science.gov (United States)

    de Villiers, Danielle; Traynor, Alison; Collins, Simon N; Shelton, Julia C

    2015-09-01

    Hypersensitivity reactions in patients receiving metal-on-metal hip replacements have been attributed to corrosion products as observed by elevated cobalt and chromium ions in the blood. Although the majority of cases are reported in metal-on-metal, incidences of these reactions have been reported in the metal-on-polyethylene patient population. To date, no in vitro study has considered cobalt release for this bearing combination. This study considered four 28 mm and seven 52 mm diameter metal-on-polyethylene bearings tested following ISO standard hip simulator conditions as well as under established abrasive conditions. These tests showed measurable cobalt in all bearings under standard conditions. Cobalt release, as well as polyethylene wear, increased with diameter, increasing from 52 to 255 ppb. The introduction of bone cement particles into the articulation doubled polyethylene wear and cobalt release while alumina particles produced significant damage on the heads demonstrated by cobalt levels of 70,700 ppb and an increased polyethylene wear from a mean value of 9-160 mm(3)/mc. Cobalt release was indicative of head damage and correlated with polyethylene wear at the next gravimetric interval. The removal of third body particles resulted in continued elevated cobalt levels in the 52 mm diameter bearings tested with alumina compared to standard conditions but the bearings tested with bone cement particles returned to standard levels. The polyethylene wear in the bone cement tested bearings also recovered to standard levels, although the alumina tested bearings continued to wear at a higher rate of 475 mm(3)/mc. Cobalt release was shown to occur in metal-on-polyethylene bearings indicating damage to the metal head resulting in increased polyethylene wear. While large diameter metal-on-polyethylene bearings may provide an increased range of motion and a reduced dislocation risk, increased levels of cobalt are likely to be released and this needs to be fully

  16. Design review and analysis for a Pratt and Whitney fluid-film bearing and seal testing rig

    Science.gov (United States)

    Childs, Dara W.

    1994-01-01

    A design review has been completed for a Pratt and Whitney (P&W)-designed fluid-film bearing and annular-seal test rig to be manufactured and installed at George C. Marshall Space Flight Center (MSFC). Issues covered in this study include: (1) the capacity requirements of the drive unit; (2) the capacity and configuration of the static loading system; (3) the capacity and configuration of the dynamic excitation system; (4) the capacity, configuration, and rotordynamic stability of a test bearing, support bearings, and shaft; and (5) the characteristics and configuration of the measurement transducers and data channels.

  17. Slope stability and bearing capacity of landfills and simple on-site test methods.

    Science.gov (United States)

    Yamawaki, Atsushi; Doi, Yoichi; Omine, Kiyoshi

    2017-07-01

    This study discusses strength characteristics (slope stability, bearing capacity, etc.) of waste landfills through on-site tests that were carried out at 29 locations in 19 sites in Japan and three other countries, and proposes simple methods to test and assess the mechanical strength of landfills on site. Also, the possibility of using a landfill site was investigated by a full-scale eccentric loading test. As a result of this, landfills containing more than about 10 cm long plastics or other fibrous materials were found to be resilient and hard to yield. An on-site full scale test proved that no differential settlement occurs. The repose angle test proposed as a simple on-site test method has been confirmed to be a good indicator for slope stability assessment. The repose angle test suggested that landfills which have high, near-saturation water content have considerably poorer slope stability. The results of our repose angle test and the impact acceleration test were related to the internal friction angle and the cohesion, respectively. In addition to this, it was found that the air pore volume ratio measured by an on-site air pore volume ratio test is likely to be related to various strength parameters.

  18. Characterization of High-Power Turbomachinery Tilting Pad Journal Bearings: First Results Obtained on a Novel Test Bench

    Directory of Open Access Journals (Sweden)

    Enrico Ciulli

    2018-01-01

    Full Text Available Tilting pad journal bearings are usually employed in turbomachines for their stable behavior at high rotational speeds. Devoted test rigs have been realized to validate the predictions of theoretical models. However, the design of new high-performance and large-size bearings needs to be supported by experimental investigations on high-performance large test rigs. The main characteristics of a recently built facility for testing large tilting pad journal bearings with diameters from 150 to 300 mm are described in this work. The test rig is versatile and can be used to test bearings of different size, configurations and to investigate the influence of many parameters, even the effect of misalignment. Sample results of the static characterization of a four-pad high-performance tilting pad journal bearing are reported evidencing some transient effects. A few sample dynamic results are also reported. The presented experimental results demonstrated the capabilities of the rig for investigating the static and the dynamic characteristics of the bearings accurately measuring slow and fast variables.

  19. Shaking Table Tests of Curved Bridge considering Bearing Friction Sliding Isolation

    Directory of Open Access Journals (Sweden)

    Lei Yan

    2016-01-01

    Full Text Available Specific to severe damage to curved bridges in earthquakes caused by the excessive force of the fixed bearings and piers, a new seismic design method on curved bridges considering bearing friction sliding isolation is proposed in this paper. Seismic model bridge and isolation model bridge with similarity ratio of 1/20 were made and the shaking table comparison test was conducted. The experimental results show that the isolation model curved bridge suffered less seismic damage than the seismic model curved bridge. The fundamental frequencies of the seismic model bridge and isolation model bridge decreased and the damping ratio increased with the increase of seismic intensity. Compared with seismic curved bridge, the maximum reduction rates of peak acceleration along the radial and tangential directions on the top of pier of the isolation model curved bridge were 47.3% and 55.5%, respectively, and the maximum reduction rate of the peak strain on the bottom of pier of the isolation model curved bridge was 43.4%. For the isolation model curved bridge, the maximum reduction rate of peak acceleration on the top of pier was 24.6% compared with that on the bottom of pier. The study results can provide experimental basis for the seismic design of curved bridges.

  20. Phase 2 THOR Steam Reforming Tests for Sodium Bearing Waste Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas R. Soelberg

    2004-01-01

    About one million gallons of acidic, hazardous, and radioactive sodium-bearing waste is stored in stainless steel tanks at the Idaho Nuclear Technology and Engineering Center (INTEC), which is a major operating facility of the Idaho National Engineering and Environmental Laboratory. Steam reforming is a candidate technology being investigated for converting the waste into a road ready waste form that can be shipped to the Waste Isolation Pilot Plant in New Mexico for interment. A steam reforming technology patented by Studsvik, Inc., and licensed to THOR Treatment Technologies has been tested in two phases using a Department of Energy-owned fluidized bed test system located at the Science Applications International Corporation (SAIC) Science and Technology Applications Research Center located in Idaho Falls, Idaho. The Phase 1 tests were reported earlier in 2003. The Phase 2 tests are reported here. For Phase 2, the process feed rate, stoichiometry, and chemistry were varied to identify and demonstrate process operation and product characteristics under different operating conditions. Two test series were performed. During the first series, the process chemistry was designed to produce a sodium carbonate product. The second series was designed to produce a more leach-resistant, mineralized sodium aluminosilicate product. The tests also demonstrated the performance of a MACT-compliant off-gas system.

  1. Field Tests on Hydrodynamic and Hybrid Operation of a Bidirectional Thrust Bearing of a Pump-Turbine

    Directory of Open Access Journals (Sweden)

    Michał Wasilczuk

    2017-12-01

    Full Text Available In vertical shaft pump turbines operating in pumped storage power plants an important role is played by a thrust bearing. Due to the bidirectional character of operation, thrust bearing tilting pads have to be supported symmetrically, which is known to be unfavourable from the point of view of their performance. Large thrust bearings have to be carefully designed so as to minimise excessive thermo-elastic pad deformations. The research into fluid film thrust bearings has been quite extensive over the years, comprising theoretical studies of bearing properties with the use of more and more sophisticated calculation codes. On the other hand, the availability of experimental field data on bearing operation is limited, for obvious reasons. In this paper the authors present part of the results of extensive field tests of a large bearing of a pump-turbine they have conducted in a pumped storage power plant. Hopefully this data will be of interest to other researchers to compare theoretical predictions to measurement data.

  2. Phase 2 TWR Steam Reforming Test for Sodium-Bearing Waste Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas R. Soelberg; Doug Marshall; Dean Taylor; Steven Bates

    2004-01-01

    About one million gallons of acidic, hazardous, and radioactive sodium-bearing waste (SBW) is stored in stainless steel tanks a the Idaho Nuclear Technology and Engineering Center (INTEC), which is a major operating facility of the Idaho National Engineering and Environmental Laboratory (INEEL). Steam reforming is a candidate technology being investigated for converting the SBW into a road ready waste form that can be shipped to the Waste Isolation Pilot Plant in New Mexico for interment. Fluidized bed steam reforming technology, licensed to ThermoChem Waste Remediation, LLC (TWR) by Manufacturing Technology Conversion International, was tested in two phases using an INEEL (Department of Energy) fluidized bed test system located at the Science Applications International Corporation (SAIC) Science and Technology Applications Research Center in Idaho Falls, Idaho. The Phase 1 tests were reported earlier. The Phase 2 tests are reported here. For Phase 2, the process feed rate, reductant stoichiometry, and process temperature were varied to identify and demonstrate how the process might be optimized to improve operation and product characteristics. The first week of testing was devoted primarily to process chemistry and the second week was devoted more toward bed stability and particle size control.

  3. A numerical test method of California bearing ratio on graded crushed rocks using particle flow modeling

    Directory of Open Access Journals (Sweden)

    Yingjun Jiang

    2015-04-01

    Full Text Available In order to better understand the mechanical properties of graded crushed rocks (GCRs and to optimize the relevant design, a numerical test method based on the particle flow modeling technique PFC2D is developed for the California bearing ratio (CBR test on GCRs. The effects of different testing conditions and micro-mechanical parameters used in the model on the CBR numerical results have been systematically studied. The reliability of the numerical technique is verified. The numerical results suggest that the influences of the loading rate and Poisson's ratio on the CBR numerical test results are not significant. As such, a loading rate of 1.0–3.0 mm/min, a piston diameter of 5 cm, a specimen height of 15 cm and a specimen diameter of 15 cm are adopted for the CBR numerical test. The numerical results reveal that the CBR values increase with the friction coefficient at the contact and shear modulus of the rocks, while the influence of Poisson's ratio on the CBR values is insignificant. The close agreement between the CBR numerical results and experimental results suggests that the numerical simulation of the CBR values is promising to help assess the mechanical properties of GCRs and to optimize the grading design. Besides, the numerical study can provide useful insights on the mesoscopic mechanism.

  4. Program for tests on magnetic bearing suspended rotor dynamics for gas turbine high temperature reactor (GTHTR300)

    International Nuclear Information System (INIS)

    Takada, Shoji; Takizuka, Takakazu; Kunitomi, Kazuhiko; Kosugiyama, Shinichi; Yan, Xing

    2003-01-01

    A program for test on rotor dynamics was planned for the turbo-machine of the Gas Turbine High Temperature Reactor (GTHTR300). The rotor system of the turbo-machine consists of a turbo-compressor rotor and a generator rotor connected with a flexible coupling, each suspended with two radial magnetic bearings. The rotors, which are flexible rotors, pass over the critical speeds of bending mode. The magnetic bearing is required to have a high load capacity, about 10 times larger than any built thus far to support a flexible rotor. In the rotor design, the standard limit of the vibration amplitude of 75 μm at the rated rotational speed of 3,600 rpm was fulfilled by optimizing the stiffness of the magnetic bearings. A test apparatus was designed to verify the design of the magnetic bearing suspended turbo-machine rotor of the GTHTR300. The test apparatus is composed of 1/3-scale test rotors, which are connected with a flexible coupling and driven by a variable speed motor. The test magnetic bearing was designed within the state-of-the-art technology to have a load capacity about 1/10 of that of the actual one. The test rotors were designed to closely simulate the critical speeds and vibration modes of the actual ones. This paper shows the test apparatus and the test plan for the magnetic bearing suspended rotor system. The present study is entrusted from the Ministry of Education, Culture, Sports, Science and Technology of Japan. (author)

  5. Demonstration, Testing and Qualification of a High Temperature, High Speed Magnetic Thrust Bearing

    Science.gov (United States)

    DeWitt, Kenneth

    2005-01-01

    The gas turbine industry has a continued interest in improving engine performance and reducing net operating and maintenance costs. These goals are being realized because of advancements in aeroelasticity, materials, and computational tools such as CFD and engine simulations. These advancements aid in increasing engine thrust-to-weight ratios, specific fuel consumption, pressure ratios, and overall reliability through higher speed, higher temperature, and more efficient engine operation. Currently, rolling element bearing and squeeze film dampers are used to support rotors in gas turbine engines. Present ball bearing configurations are limited in speed (bearings require extensive preventative maintenance in order to assure their safe operation. Since these bearings are at their operational limits, new technologies must be found in order to take advantage of other advances. Magnetic bearings are well suited to operate at extreme temperatures and higher rotational speeds and are a promising solution to the problems that conventional rolling element bearings present. Magnetic bearing technology is being developed worldwide and is considered an enabling technology for new engine designs. Using magnetic bearings, turbine and compressor spools can be radically redesigned to be significantly larger and stiffer with better damping and higher rotational speeds. These advances, a direct result of magnetic bearing technology, will allow significant increases in engine power and efficiency. Also, magnetic bearings allow for real-time, in-situ health monitoring of the system, lower maintenance costs and down time.

  6. A compression and shear loading test of concrete filled steel bearing wall

    International Nuclear Information System (INIS)

    Akiyama, Hiroshi; Sekimoto, Hisashi; Fukihara, Masaaki; Nakanishi, Kazuo; Hara, Kiyoshi.

    1991-01-01

    Concrete-filled steel bearing walls called SC structure which are the composite structure of concrete and steel plates have larger load-carrying capacity and higher ductility as compared with conventional RC structures, and their construction method enables the rationalization of construction procedures at sites and the shortening of construction period. Accordingly, the SC structures have become to be applied to the inner concrete structures of PWR nuclear power plants, and subsequently, it is planned to apply them to the auxiliary buildings of nuclear power plants. The purpose of this study is to establish a rational design method for the SC structures which can be applied to the auxiliary buildings of nuclear power plants. In this study, the buckling strength of surface plates and the ultimate strength of the SC structure were evaluated with the results of the compression and shear tests which have been carried out. The outline of the study and the tests, the results of the compression test and the shear test and their evaluation are reported. Stud bolts were effective for preventing the buckling of surface plates. The occurrence of buckling can be predicted analytically. (K.I.)

  7. Polar Bears

    Science.gov (United States)

    Amstrup, Steven C.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

    2002-01-01

    Polar bears (Ursus maritimus) are hunted throughout most of their range. In addition to hunting polar bears of the Beaufort Sea region are exposed to mineral and petroleum extraction and related human activities such as shipping road-building, and seismic testing (Stirling 1990).Little was known at the start of this project about how polar bears move about in their environment, and although it was understood that many bears travel across political borders, the boundaries of populations had not been delineated (Amstrup 1986, Amstrup et al. 1986, Amstrup and DeMaster 1988, Garner et al. 1994, Amstrup 1995, Amstrup et al. 1995, Amstrup 2000).As human populations increase and demands for polar bears and other arctic resources escalate, managers must know the sizes and distributions of the polar bear populations. Resource managers also need reliable estimates of breeding rates, reproductive intervals, litter sizes, and survival of young and adults.Our objectives for this research were 1) to determine the seasonal and annual movements of polar bears in the Beaufort Sea, 2) to define the boundaries of the population(s) using this region, 3) to determine the size and status of the Beaufort Sea polar bear population, and 4) to establish reproduction and survival rates (Amstrup 2000).

  8. Testing of bearing materials for large two-stroke marine diesel engines

    DEFF Research Database (Denmark)

    Vølund, Anders; Klit, Peder; Persson, Sebastian

    2017-01-01

    In large two-stroke marine diesel engines, bearings are designed to last the lifetime of the engine. The design has shown very good service experiences. The design parameters of the main bearings are, among others, based on the average maximum specific load which the bearing should operate under....... In general, the frictional loss is less than 1% of the nominal power of the engine but is still a target for optimization. Fatigue mechanisms of bearing lining material are not fully understood and the design limits with regards to minimum oil film thickness, max oil film pressure and oil film pressure...

  9. Testing of Bearing Materials for Large Two-stroke Marine Diesel Engines

    DEFF Research Database (Denmark)

    Klit, Peder; Persson, Sebastian; Vølund, Anders

    2013-01-01

    In large two-stroke marine diesel engines bearings are designed with the intention that these need not be replaced during the life of the engine. The design has shown very good service experiences. The design parameters of the main bearings are, among others, based on the average maximum specific...... load which the bearing should operate under. In general, the frictional loss is less than 1% of the nominal power of the engine but is still a target for optimization. Fatigue mechanisms of bearing lining material are not fully understood and the design limits with regards to minimum oil film thickness...

  10. Tank Applied Testing of Load-Bearing Multilayer Insulation (LB-MLI)

    Science.gov (United States)

    Johnson, Wesley L.; Valenzuela, Juan G.; Feller, Jerr; Plachta, Dave

    2014-01-01

    The development of long duration orbital cryogenic storage systems will require the reduction of heat loads into the storage tank. In the case of liquid hydrogen, complete elimination of the heat load at 20 K is currently impractical due to the limitations in lift available on flight cryocoolers. In order to reduce the heat load, without having to remove heat at 20 K, the concept of Reduced Boil-Off uses cooled shields within the insulation system at approximately 90 K. The development of Load-Bearing Multilayer Insulation (LB-MLI) allowed the 90 K shield with tubing and cryocooler attachments to be suspended within the MLI and still be structurally stable. Coupon testing both thermally and structurally were performed to verify that the LB-MLI should work at the tank applied level. Then tank applied thermal and structural (acoustic) testing was performed to demonstrate the functionality of the LB-MLI as a structural insulation system. The LB-MLI showed no degradation of thermal performance due to the acoustic testing and showed excellent thermal performance when integrated with a 90 K class cryocooler on a liquid hydrogen tank.

  11. Modifications to Marshall's Annular Seal Test (MAST) Rig and Facility for Improved Rotordynamic Coefficient Testing of Annular Seals and Fluid Film Bearings

    Science.gov (United States)

    Darden, J. M.; Earhart, E. M.

    2011-01-01

    The limits of rotordynamic stability continue to be pushed by the high power densities and rotational speeds of modern rocket engine turbomachinery. Destabilizing forces increase dramatically with rotor speed. Rotordynamic stability is lost when these destabilizing forces overwhelm the stabilizing forces. The vibration from the unstable rotor grows until it is limited by some nonlinearity. For example, a rolling element bearing with a stiffness characteristic that increases with deflection may limit the vibration amplitude. The loads and deflections resulting from this limit cycle vibration (LCV) can lead to bearing and seal damage which promotes ever increasing levels of subsynchronous vibration. Engineers combat LCV by introducing rotordynamic elements that generate increased stabilizing forces and reduced destabilizing forces. For example, replacing a labyrinth seal with a damping seal results in substantial increases in the damping and stiffness rotordynamic coefficients. Adding a swirl brake to the damping seal greatly reduces the destabilizing cross-coupled forces generated by the damping seal for even further increases in the stabilizing capacity. Marshall?s Annular Seal Test (MAST) rig is designed to experimentally measure the stabilizing capacity of new annular seal designs. The rig has been moved to a new facility and outfitted with a new slave bearing to allow increased test durations and to enable the testing of fluid film bearings. The purpose of this paper is to describe the new facility and the new bearing arrangement. Several novel seal and bearing designs will also be discussed.

  12. High-Temperature (1000 F) Magnetic Thrust Bearing Test Rig Completed and Operational

    Science.gov (United States)

    Montague, Gerald T.

    2005-01-01

    Large axial loads are induced on the rolling element bearings of a gas turbine. To extend bearing life, designers use pneumatic balance pistons to reduce the axial load on the bearings. A magnetic thrust bearing could replace the balance pistons to further reduce the axial load. To investigate this option, the U.S. Army Research Laboratory, the NASA Glenn Research Center, and Texas A&M University designed and fabricated a 7-in.- diameter magnetic thrust bearing to operate at 1000 F and 30,000 rpm, with a 1000-lb load capacity. This research was funded through a NASA Space Technology Transfer Act with Allison Advance Development Company under the Ultra-Efficient Engine Technology (UEET) Intelligent Propulsion Systems Foundation Technology project.

  13. Mechanical property test of natural rubber bearing for the evaluation of uncertainty value of seismic isolation devices

    International Nuclear Information System (INIS)

    Kim, Min Kyu; Kim, Jung Han; Choi, In Kil

    2012-01-01

    Seismic safety of NPP is one of the most important issues in a nuclear field after great east Japan earthquake in 2011. For the improvement of seismic safety of nuclear power plant, seismic isolation is the easiest solution for increasing the seismic safety. Otherwise, the application of seismic isolation devices for nuclear power plants doesn't make the seismic risk of NPP increases always. The rubber bearing have many uncertainties of material properties and large displacement should absorb according to the application of isolation devices. In this study, for the evaluation of uncertainty of the material properties of rubber bearing, material tests for rubber and mechanical properties test for natural rubber bearing were performed. For the evaluation of effect of hardness of rubber, 4 kinds of rubber hardness for material property tests and 2 kinds of rubber hardness for mechanical property test were considered. As a result, the variation of material properties is higher than that of mechanical properties of natural rubber bearings

  14. Test Summary Report INEEL Sodium-Bearing Waste Vitrification Demonstration RSM-01-1

    Energy Technology Data Exchange (ETDEWEB)

    Goles, Ronald W.; Perez, Joseph M.; Macisaac, Brett D.; Siemer, Darryl D.; Mccray, John A.

    2001-05-21

    The U.S. Department of Energy's Idaho National Engineering and Environmental Laboratory is storing large amounts of radioactive and mixed wastes. Most of the sodium-bearing wastes have been calcined, but about a million gallons remain uncalcined, and this waste does not meet current regulatory requirements for long-term storage and/or disposal. As a part of the Settlement Agreement between DOE and the State of Idaho, the tanks currently containing SBW are to be taken out of service by December 31, 2012, which requires removing and treatment the remaining SBW. Vitrification is the option for waste disposal that received the highest weighted score against the criteria used. Beginning in FY 2000, the INEEL high-level waste program embarked on a program for technology demonstration and development that would lead to conceptual design of a vitrification facility in the event that vitrification is the preferred alternative for SBW disposal. The Pacific Northwest National Laborator's Research-Scale Melter was used to conduct these initial melter-flowsheet evaluations. Efforts are underway to reduce the volume of waste vitrified, and during the current test, an overall SBW waste volume-reduction factor of 7.6 was achieved.

  15. Testing methods for using high-resolution satellite imagery to monitor polar bear abundance and distribution

    Science.gov (United States)

    LaRue, Michelle A.; Stapleton, Seth P.; Porter, Claire; Atkinson, Stephen N.; Atwood, Todd C.; Dyck, Markus; Lecomte, Nicolas

    2015-01-01

    High-resolution satellite imagery is a promising tool for providing coarse information about polar species abundance and distribution, but current applications are limited. With polar bears (Ursus maritimus), the technique has only proven effective on landscapes with little topographic relief that are devoid of snow and ice, and time-consuming manual review of imagery is required to identify bears. Here, we evaluated mechanisms to further develop methods for satellite imagery by examining data from Rowley Island, Canada. We attempted to automate and expedite detection via a supervised spectral classification and image differencing to expedite image review. We also assessed what proportion of a region should be sampled to obtain reliable estimates of density and abundance. Although the spectral signature of polar bears differed from nontarget objects, these differences were insufficient to yield useful results via a supervised classification process. Conversely, automated image differencing—or subtracting one image from another—correctly identified nearly 90% of polar bear locations. This technique, however, also yielded false positives, suggesting that manual review will still be required to confirm polar bear locations. On Rowley Island, bear distribution approximated a Poisson distribution across a range of plot sizes, and resampling suggests that sampling >50% of the site facilitates reliable estimation of density (CV in certain areas, but large-scale applications remain limited because of the challenges in automation and the limited environments in which the method can be effectively applied. Improvements in resolution may expand opportunities for its future uses.

  16. Coordinated control of a space manipulator tested by means of an air bearing free floating platform

    Science.gov (United States)

    Sabatini, Marco; Gasbarri, Paolo; Palmerini, Giovanni B.

    2017-10-01

    A typical approach studied for the guidance of next generation space manipulators (satellites with robotic arms aimed at autonomously performing on-orbit operations) is to decouple the platform and the arm maneuvers, which are supposed to happen sequentially, mainly because of safety concerns. This control is implemented in this work as a two-stage Sequential control, where a first stage calls for the motion of the platform and the second stage calls for the motion of the manipulator. A second novel strategy is proposed, considering the platform and the manipulator as a single multibody system subject to a Coordinated control, with the goal of approaching and grasping a target spacecraft. At the scope, a region that the end effector can reach by means of the arm motion with limited reactions on the platform is identified (the so called Reaction Null workspace). The Coordinated control algorithm performs a gain modulation (finalized to a balanced contribution of the platform and arm motion) as a function of the target position within this Reaction Null map. The result is a coordinated maneuver in which the end effector moves thanks to the platform motion, predominant in a first phase, and to the arm motion, predominant when the Reaction-Null workspace is reached. In this way the collision avoidance and attitude over-control issues are automatically considered, without the need of splitting the mission in independent (and overall sub-optimal) segments. The guidance and control algorithms are first simulated by means of a multibody code, and successively tested in the lab by means of a free floating platform equipped with a robotic arm, moving frictionless on a flat granite table thanks to air bearings and on-off thrusters; the results will be discussed in terms of optimality of the fuel consumption and final accuracy.

  17. Worst-Case" Simulant for INTEC Soduim-Bearing Waste Vitrification Tests

    Energy Technology Data Exchange (ETDEWEB)

    Christian, Jerry Dale; Batcheller, Thomas Aquinas

    2001-09-01

    The Idaho Nuclear Technology and Engineering Center (INTEC) is developing technologies to process the radioactive liquid sodium-bearing waste from the waste tanks at INTEC to solidify the waste into a form suitable for disposition in a National high-level waste repository currently being considered at Yucca Mountain, Nevada. The requirement is for a qualified glass waste form. Therefore, vitrification is being developed using laboratory, research-scale, and pilot scale melters. While some laboratory experiments can be done with actual waste, the larger scale and most laboratory experiments must be done on non-radioactive simulant waste solutions. Some tests have previously been done on simulants of a representative waste that has been concentrated and will remain unchanged in tank WM-180 until it is vitrified. However, there is a need to develop glass compositions that will accommodate all future wastes in the tanks. Estimates of those future waste compositions have been used along with current compositions to develop a “worst-case” waste composition and a simulant preparation recipe suitable for developing a bracketing glass formulation and for characterizing the flowpath and decontamination factors of pertinent off-gas constituents in the vitrification process. The considerations include development of criteria for a worst-case composition. In developing the criteria, the species that are known to affect vitrification and glass properties were considered. Specific components that may need to be characterized in the off-gas cleanup system were considered in relation to detection limits that would need to be exceeded in order to track those components. Chemical aspects of various constituent interactions that should be taken into account when a component may need to be increased in concentration from that in the actual waste for detection in experiments were evaluated. The worst-case waste simulant composition is comprised of the highest concentration of each

  18. Standard Test Methods for Detecting Susceptibility to Intergranular Corrosion in Wrought, Nickel-Rich, Chromium-Bearing Alloys

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 These test methods cover two tests as follows: 1.1.1 Method A, Ferric Sulfate-Sulfuric Acid Test (Sections 3-10, inclusive)—This test method describes the procedure for conducting the boiling ferric sulfate—50 % sulfuric acid test which measures the susceptibility of certain nickel-rich, chromium-bearing alloys to intergranular corrosion (see Terminology G 15), which may be encountered in certain service environments. The uniform corrosion rate obtained by this test method, which is a function of minor variations in alloy composition, may easily mask the intergranular corrosion components of the overall corrosion rate on alloys N10276, N06022, N06059, and N06455. 1.1.2 Method B, Mixed Acid-Oxidizing Salt Test (Sections 11-18, inclusive)—This test method describes the procedure for conducting a boiling 23 % sulfuric + 1.2 % hydrochloric + 1 % ferric chloride + 1 % cupric chloride test which measures the susceptibility of certain nickel-rich, chromium-bearing alloys to display a step function increa...

  19. Experiments with needle bearings

    Science.gov (United States)

    Ferretti, Pericle

    1933-01-01

    Experiments and results are presented in testing needle bearings, especially in comparison with roller bearings. Reduction in coefficient of friction is discussed as well as experimental methods and recording devices.

  20. Hydraulic testing plan for the Bear Creek Valley Treatability Study, Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1997-09-01

    The Bear Creek Valley (BCV) Treatability Study is intended to provide site-specific data defining potential treatability technologies applicable to contaminated groundwater and surface water. The ultimate goal of this effort is to install a treatment system that will remove uranium, technetium, nitrate, and several metals from groundwater before it reaches Bear Creek. This project directly supports the BCV Feasibility Study. Part of the Treatability Study, Phase II Hydraulic Performance Testing, will produce hydraulic and treatment performance data required to design a long-term treatment system. This effort consists of the installation and testing of two groundwater collection systems: a trench in the vicinity of GW-835 and an angled pumping well adjacent to NT-1. Pumping tests and evaluations of gradients under ambient conditions will provide data for full-scale design of treatment systems. In addition to hydraulic performance, in situ treatment chemistry data will be obtained from monitoring wells installed in the reactive media section of the trench. The in situ treatment work is not part of this test plan. This Hydraulic Testing Plan describes the location and installation of the trench and NT-1 wells, the locations and purpose of the monitoring wells, and the procedures for the pumping tests of the trench and NT-1 wells

  1. Impact of HIV counseling and testing among child-bearing women in Kinshasa, Zaïre.

    Science.gov (United States)

    Heyward, W L; Batter, V L; Malulu, M; Mbuyi, N; Mbu, L; St Louis, M E; Kamenga, M; Ryder, R W

    1993-12-01

    To determine the impact of HIV counseling and testing among child-bearing women. Mama Yemo Hospital in Kinshasa, Zaïre. After informed consent, 187 HIV-seropositive and 177 HIV-seronegative child-bearing women received pre- and post-test counseling for HIV infection. Participant knowledge of HIV/AIDS and plans for notifying partners of serologic status and contraceptive use at the time of counseling, and actual partner involvement and contraception use 12 months later. During pre-test counseling, participant knowledge of HIV infection was high, although 30% of women were unaware of perinatal HIV transmission, and 50% did not know that HIV infection could be asymptomatic. At post-test counseling, 70% of mothers (47% of HIV-seropositive, 94% of HIV-seronegative) intended to notify their partners and have joint counseling and testing, although after 12 months, only 2.2% of all women and 7.9% of those who desired assistance to notify their partner returned with their partners for joint counseling and testing. Similarly, 86% planned to use birth control (61% condoms), with HIV-seropositive women more likely to prefer condoms than HIV-seronegative women (71 versus 53%; P heterosexual and perinatal HIV transmission in families with an HIV-infected woman, counseling should also include their male partners.

  2. Transient Lift-Off Test Results for an Experimental Hybrid Bearing in Air

    Science.gov (United States)

    2009-12-01

    Table 20 Start and stop points of rub from super synchronous vibration observation ..... 81 Distribution A: Approved for public release; distribution...between 0.45-0.50. The pressure ratio ( rcP ) is the recess pressure divided by the supply pressure as shown in Eq. (1). as ar rc PP PP P − − = (1...Ratio on the Performance of an Orifice-Compensated Hybrid Bearing,” ASME Journal of Vibration and Acoustics, 120, No. 4, October 1998, pp. 930-936

  3. Bearing system

    Science.gov (United States)

    Kapich, Davorin D.

    1987-01-01

    A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

  4. Kinetic load bearing capacity of impulsively loaded reinforced concrete members. Tests on reinforced concrete beams. Pt. 2

    International Nuclear Information System (INIS)

    Limberger, E.; Brandes, K.; Herter, J.; Berner, K.

    1986-01-01

    In several tests on reinforced concrete beams the kinetic load bearing capacity as well as the energy absorption capacity has been evaluated. This report presents results of 18 tests. For the various test parameters always a pair of 'identical' beams were tested under static and dynamic load conditions. For the beams loaded at midspan failure occurred in plastic hinges either by fracture of the tensile reinforcement or by crushing of the concrete compressive zone. The 18 tests continue the 33 tests which were described in the first part of the report on beam tests. As a general test result, it can be stated that for bending failure the resistance as well as the deformability of the beam is mainly influenced by the mechanical properties of the reinforcing steel. The comparison of the results of static tests to those of dynamic tests show the increase of the deformation resistance as well as the increase of the deformability which stands in good correlation to the strain rate dependence of the characteristic values of the steel found in tensile tests. (orig./IHOE) With 81 figs [de

  5. Kinetic load bearing capacity of impulsively loaded reinforced concrete members. Tests on reinforced concrete beams. Pt. 1

    International Nuclear Information System (INIS)

    Limberger, E.; Brandes, K.; Herter, J.; Berner, K.

    1986-01-01

    The kinetic load bearing capacity of reinforced concrete beams has been evaluated in tests on 33 specimens. The R.C.-beams (3,20 m span, 25 cm width, 30 cm - 50 cm height) were simply supported and centrally loaded. In the test series were loaded identical specimens up to failure under static and under impact load (fracture of beams after 30 ms to 70 ms) as well. In the beams occured plastic hinges and they failed by fracture of the tensile reinforcement or by crushing of the concrete compression zone. The following parameters were varied: height of beams, type of reinforcement, amount of tensile and compression reinforcement, concrete compression strength, and load time history. It is recognized from the results, that only the mean value of the deformation rate characterizes the response of the specimens. This can be stated for the range of parameter values appearing in reinforced concrete structures subjected to aircraft crash and in the reported tests. In all tests occured ductile failure. The total deformation up to failure reached in dynamic tests at least the static values or exeeded those considerably. (orig.) With 153 figs [de

  6. Removal of Lipid from Serum Increases Coherence between Brucellosis Rapid Agglutination Test and Enzyme-linked Immunosorbent Assay in Bears in Alaska, USA.

    Science.gov (United States)

    Godfroid, Jacques; Beckmen, Kimberlee; Helena Nymo, Ingebjørg

    2016-10-01

    In cases of chronic Brucella spp. infection, results of the rose bengal plate test (RBPT) and indirect enzyme-linked immunosorbent assay (ELISA) should be coherent, as reported in controlled conditions in the literature. We compared RBPT and ELISA results in 58 Alaska grizzly bears ( Ursus arctos horribilis), eight Kodiak brown bears ( Ursus arctos middendorffi), and six Alaska Peninsula brown bears ( Ursus arctos gyas). Of the 72 bears tested, 42 (58%) were ELISA positive and 53 (73%) were RBPT positive. However, the coherence between the tests was only fair (K=0.37, SE=0.11), suggesting that either the serologic results were not compatible with Brucella spp. infection or that there was a technical problem with the tests. To address a potential technical problem, we performed a 30-min chloroform/centrifugation cleanup. Following cleanup, the ELISA identified 43 positives (59%) and the RBPT identified 47 (65%), and the coherence between the tests was much improved (K=0.80, SE=0.07). We recommend cleaning wildlife sera with a high lipid content before performing RBPT and performing RBPT and ELISA in parallel to assess coherence. Our results suggest that Alaskan brown bears have been exposed to Brucella spp.

  7. Evaluation of bearing capacity of piles from cone penetration test data.

    Science.gov (United States)

    1999-11-01

    This study presents an evaluation of the performance of eight cone penetration test (CPT) methods in predicting the ultimate load carrying capacity of square precast prestressed concrete (PPC) piles driven into Louisiana soils. A search in the DOTD f...

  8. Development of and tests with the NMR technique to detect water bearing fractures

    CSIR Research Space (South Africa)

    Meyer, R

    2007-01-01

    Full Text Available The theory and application of Nuclear Magnetic Resonance Soundings also referred to as Magnetic Resonance Soundings (MRS) for the exploration of groundwater in porous aquifers has been well developed and tested. To date the method is usually applied...

  9. Equipping a glovebox for waste form testing and characterization of plutonium bearing materials

    International Nuclear Information System (INIS)

    Noy, M.; Johnson, S.G.; Moschetti, T.L.

    1997-01-01

    The recent decision by the Department of Energy to pursue a hybrid option for the disposition of weapons plutonium has created the need for additional facilities that can examine and characterize waste forms that contain Pu. This hybrid option consists of the placement of plutonium into stable waste forms and also into mixed oxide fuel for commercial reactors. Glass and glass-ceramic waste forms have a long history of being effective hosts for containing radionuclides, including plutonium. The types of tests necessary to characterize the performance of candidate waste forms include: static leaching experiments on both monolithic and crushed waste forms, microscopic examination, and density determination. Frequently, the respective candidate waste forms must first be produced using elevated temperatures and/or high pressures. The desired operations in the glovebox include, but are not limited to the following: (1) production of vitrified/sintered samples, (2) sampling of glass from crucibles or other vessels, (3) preparing samples for microscopic inspection and monolithic and crushed static leach tests, and (4) performing and analyzing leach tests in situ. This paper will describe the essential equipment and modifications that are necessary to successfully accomplish the goal of outfitting a glovebox for these functions

  10. Magnetic Bearing

    OpenAIRE

    Anbuselvan. T; Vinothkumar. K; Sai Vikash. M

    2013-01-01

    The use of bearings is essential to all types of machines, especially in marine aspects they provide the function of supporting heavier component in a desired position. These bearings have contact with the rotating part and causes surface wear which can be controlled by lubrication. Researches have raised the standards of performance for rotating equipment by providing robust, cost effective, easy to implement magnetic bearing solutions. Use of magnetic bearings in ships can be more advantag...

  11. Identification Methods and Test Results for Tilting Pad and Fixed Geometry Journal Bearing Dynamic Coefficients – A Review

    Directory of Open Access Journals (Sweden)

    T.W. Dimond

    2009-01-01

    Full Text Available Fluid film journal bearings (FFBs are used to support high-speed rotors in turbomachinery which often operate above the rotor first bending critical speed. The FFBs provide both lateral support and dynamic coefficients: stiffness, damping, and mass terms, related to machine vibrations. Detailed numerical values of the bearing dynamic characteristics are necessary for proper design and operation of rotating machinery.

  12. Operation Test of the Supercritical CO{sub 2} Compressor Supported with Active Magnetic Bearing

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Jae Eun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Cho, Seong Kuk; Lee, Jeong IK [KAIST, Daejeon (Korea, Republic of)

    2016-10-15

    In this paper, the operation test status of the SCIEL sCO{sub 2} AMB Compressor is briefly described. The Supercritical CO{sub 2} Brayton Cycle Integral Experiment Loop (SCIEL) has been installed in Korea Atomic Energy Research Institute (KAERI) to develop the element technologies for the sCO{sub 2} cycle power generation system. The operation of the SCIEL has mainly focused on sCO{sub 2} compressor development and establishing sCO{sub 2} system control logic. The installation of the SCIEL low compression loop was finished in December 2014 and research team succeeded in generating electric power on the supercritical state of the CO{sub 2} in May 2015. The SCIEL has been built in KAERI to develop the element technologies and the system control logics for the sCO{sub 2} cycle power conversion unit of the next generation reactor. For the stable operation of the sCO{sub 2} compressor under high rotational speed, the AMB sCO{sub 2} compressor was developed and achieved the maximum 40,000 rpm.

  13. Changes in blood glucose and insulin responses to intravenous glucose tolerance tests and blood biochemical values in adult female Japanese black bears (Ursus thibetanus japonicus).

    Science.gov (United States)

    Kamine, Akari; Shimozuru, Michito; Shibata, Haruki; Tsubota, Toshio

    2012-02-01

    The metabolic mechanisms to circannual changes in body mass of bears have yet to be elucidated. We hypothesized that the Japanese black bear (Ursus thibetanus japonicus) has a metabolic mechanism that efficiently converts carbohydrates into body fat by altering insulin sensitivity during the hyperphagic stage before hibernation. To test this hypothesis, we investigated the changes in blood biochemical values and glucose and insulin responses to intravenous glucose tolerance tests (IVGTT) during the active season (August, early and late November). Four, adult, female bears (5-17 years old) were anesthetized with 6 mg/kg TZ (tiletamine HCl and zolazepam HCl) in combination with 0.1 mg/kg acepromazine maleate. The bears were injected intravenously with glucose (0.5 g/kg of body mass), and blood samples were obtained before, at, and intermittently after glucose injection. The basal triglycerides concentration decreased significantly with increase in body mass from August to November. Basal levels of plasma glucose and serum insulin concentrations were not significantly different among groups. The results of IVGTT demonstrated the increased peripheral insulin sensitivity and glucose tolerance in early November. In contrast, peripheral insulin resistance was indicated by the exaggerated insulin response in late November. Our findings suggest that bears shift their glucose and lipid metabolism from the stage of normal activity to the hyperphagic stage in which they show lipogenic-predominant metabolism and accelerate glucose uptake by increasing the peripheral insulin sensitivity.

  14. Investigation of gas hydrate-bearing sandstone reservoirs at the "Mount Elbert" stratigraphic test well, Milne Point, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Boswell, R.M.; Hunter, R. (ASRC Energy Services, Anchorage, AK); Collett, T. (USGS, Denver, CO); Digert, S. (BP Exploration (Alaska) Inc., Anchorage, AK); Hancock, S. (RPS Energy Canada, Calgary, Alberta, Canada); Weeks, M. (BP Exploration (Alaska) Inc., Anchorage, AK); Mt. Elbert Science Team

    2008-01-01

    In February 2007, the U.S. Department of Energy, BP Exploration (Alaska), Inc., and the U.S. Geological Survey conducted an extensive data collection effort at the "Mount Elbert #1" gas hydrates stratigraphic test well on the Alaska North Slope (ANS). The 22-day field program acquired significant gas hydrate-bearing reservoir data, including a full suite of open-hole well logs, over 500 feet of continuous core, and open-hole formation pressure response tests. Hole conditions, and therefore log data quality, were excellent due largely to the use of chilled oil-based drilling fluids. The logging program confirmed the existence of approximately 30 m of gashydrate saturated, fine-grained sand reservoir. Gas hydrate saturations were observed to range from 60% to 75% largely as a function of reservoir quality. Continuous wire-line coring operations (the first conducted on the ANS) achieved 85% recovery through 153 meters of section, providing more than 250 subsamples for analysis. The "Mount Elbert" data collection program culminated with open-hole tests of reservoir flow and pressure responses, as well as gas and water sample collection, using Schlumberger's Modular Formation Dynamics Tester (MDT) wireline tool. Four such tests, ranging from six to twelve hours duration, were conducted. This field program demonstrated the ability to safely and efficiently conduct a research-level openhole data acquisition program in shallow, sub-permafrost sediments. The program also demonstrated the soundness of the program's pre-drill gas hydrate characterization methods and increased confidence in gas hydrate resource assessment methodologies for the ANS.

  15. Journal bearing

    Science.gov (United States)

    Menke, John R.; Boeker, Gilbert F.

    1976-05-11

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

  16. Development and test of model apparatus of non-contact spin processor for photo mask production applying radial-type superconducting magnetic bearing

    International Nuclear Information System (INIS)

    Saito, Kimiyo; Fukui, Satoshi; Maezawa, Masaru; Ogawa, Jun; Oka, Tetsuo; Sato, Takao

    2013-01-01

    Highlights: ► We develop test spinner for non-contact spinning process in photo mask production. ► This test spinner shows improved spinning ability compared with our previous one. ► Large vertical movement of turn table still occurs during acceleration. ► Method to control vertical movement of turn table should be developed in next step. -- Abstract: In semiconductor devices, miniaturization of circuit patterning on wafers is required for higher integrations of circuit elements. Therefore, very high tolerance and quality are also required for patterning of microstructures of photo masks. The deposition of particulate dusts generated from mechanical bearings of the spin processor in the patterns of the photo mask is one of main causes of the deterioration of pattern preciseness. In our R and D, application of magnetic bearing utilizing bulk high temperature superconductors to the spin processors has been proposed. In this study, we develop a test spinner for the non-contact spinning process in the photo mask production system. The rotation test by using this test spinner shows that this test spinner accomplishes the improvement of the spinning ability compared with the test spinner developed in our previous study. This paper describes the rotation test results of the new test spinner applying the magnetic bearing with bulk high temperature superconductors

  17. Fluorine lubricated bearing technology

    Science.gov (United States)

    Mallaire, F. R.

    1973-01-01

    An experimental program was conducted to evaluate and select materials for ball bearings intended for use in liquid fluorine and/or FLOX. The ability of three different ball-separator materials, each containing nickel, to form and transfer a nickel fluoride film to provide effective lubrication at the required areas of a ball bearing operating in liquid fluorine was evaluated. In addition, solid lubrication of a ball bearing operating in liquid fluorine by either a fused fluoride coating applied to all surfaces of the ball separator or by a fluoride impregnation of porous sintered material ball separators was evaluated. Less bearing wear occurred when tests were conducted in the less reactive FLOX. Bearings fabricated from any of the materials tested would have relatively short wear lives and would require frequent replacement in a reusable engine.

  18. Shaking table test of a base isolated model in main control room of nuclear power plant using LRB (lead rubber bearing)

    International Nuclear Information System (INIS)

    Ham, K. W.; Lee, K. J.; Suh, Y. P.

    2005-01-01

    LRB(Lead Rubber Bearing) is a widely used isolation system which is installed between equipment and foundation to reduce seismic vibration from ground. LRB is consist of bearings which are resistant to lateral motion and torsion and has a high vertical stiffness. For that reason, several studies are conducted to apply LRB to the nuclear power plant. In this study, we designed two types of main control floor systems (type I, type II) and a number of shaking table tests with and without isolation system were conducted to evaluate floor isolation effectiveness of LRB

  19. Converting Simulated Sodium-bearing Waste into a Single Solid Waste Form by Evaporation: Laboratory- and Pilot-Scale Test Results on Recycling Evaporator Overheads

    International Nuclear Information System (INIS)

    Griffith, D.; D. L. Griffith; R. J. Kirkham; L. G. Olson; S. J. Losinski

    2004-01-01

    Conversion of Idaho National Engineering and Environmental Laboratory radioactive sodium-bearing waste into a single solid waste form by evaporation was demonstrated in both flask-scale and pilot-scale agitated thin film evaporator tests. A sodium-bearing waste simulant was adjusted to represent an evaporator feed in which the acid from the distillate is concentrated, neutralized, and recycled back through the evaporator. The advantage to this flow sheet is that a single remote-handled transuranic waste form is produced in the evaporator bottoms without the generation of any low-level mixed secondary waste. However, use of a recycle flow sheet in sodium-bearing waste evaporation results in a 50% increase in remote-handled transuranic volume in comparison to a non-recycle flow sheet

  20. Model Test Research on the End Bearing Behavior of the Large-Diameter Cast-in-Place Concrete Pile for Jointed Rock Mass

    Directory of Open Access Journals (Sweden)

    Jingwei Cai

    2016-01-01

    Full Text Available For large-diameter, cast-in-place concrete piles, the end bearing capacity of a single pile is affected by discontinuous surfaces that exist in natural rock masses when the bearing layer of the pile end is located in the rock layer. In order to study the influence of the jointed dip angle on the bearing characteristics of the pile end, the discrete element models are adopted to simulate the mechanical characteristics of the jointed rock masses, and the model tests of the failure mode of the jointed rock masses were also designed. The results of the numerical calculations and modeling tests show that the joints, which have a filtering effect on the internal stress of the bedrock located at the pile end, change the load transferring paths. And the failure mode of the jointed rock foundation also changes as jointed dip angle changes. The rock located at the pile end generally presents a wedge failure mode. In addition, the Q-S curves obtained by model tests show that the ultimate end bearing capacity of a single pile is influenced by the jointed dip angle. The above results provide an important theoretical basis for how to correctly calculate end resistance for a cast-in-place concrete pile.

  1. Investigation of gas hydrate-bearing sandstone reservoirs at the Mount Elbert stratigraphic test well, Milne Point, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Boswell, R. [United States Dept. of Energy, Morgantown, WV (United States). National Energy Technology Lab; Hunter, R. [ASRC Energy Services, Anchorage, AK (United States); Collett, T. [United States Geological Survey, Denver, CO (United States); Digert, S.; Weeks, M. [BP Exploration Alaska Inc., Anchorage, AK (United States); Hancock, S. [RPS Energy Canada, Calgary, AB (Canada)

    2008-07-01

    Gas hydrates occur within the shallow sand reservoirs on the Alaska North Slope (ANS). The mean estimate for gas hydrate in-place resources on the ANS is 16.7 trillion cubic metres. In the past, they were viewed primarily as a drilling hazard to be managed during the development of deeper oil resources. In 2002, a cooperative research program was launched to help determine the potential for environmentally-sound and economically-viable production of methane from gas hydrates. Additional objectives were to refine ANS gas hydrate resource potential, improve the geologic and geophysical methods used to locate and asses gas hydrate resources, and develop numerical modeling capabilities that are essential in both planning and evaluating gas hydrate field programs. This paper reviewed the results of the an extensive data collection effort conducted at the Mount Elbert number 1 gas hydrates stratigraphic test well on the ANS. The 22-day field program acquired significant gas hydrate-bearing reservoir data, including a suite of open-hole well logs, over 500 feet of continuous core, and open-hole formation pressure response tests. The logging program confirmed the existence of approximately 30 m of gas hydrate saturated, fine-grained sand reservoir. Gas hydrate saturations were observed to range from 60 to 75 per cent. Continuous wire-line coring operations achieved 85 per cent recovery. The Mount Elbert field program also involved gas and water sample collection. It demonstrated the ability to safely and efficiently conduct a research-level open-hole data acquisition program in shallow, sub-permafrost sediments and increased confidence in gas hydrate resource assessment methodologies for the ANS. 10 refs., 9 figs.

  2. GAS BEARING

    Science.gov (United States)

    Skarstrom, C.W.

    1960-09-01

    A gas lubricated bearing for a rotating shaft is described. The assembly comprises a stationary collar having an annular member resiliently supported thereon. The collar and annular member are provided with cooperating gas passages arranged for admission of pressurized gas which supports and lubricates a bearing block fixed to the rotatable shaft. The resilient means for the annular member support the latter against movement away from the bearing block when the assembly is in operation.

  3. Thrust bearing

    Science.gov (United States)

    Anderson, W. J. (Inventor)

    1976-01-01

    A gas lubricated thrust bearing is described which employs relatively rigid inwardly cantilevered spokes carrying a relatively resilient annular member or annulus. This annulus acts as a beam on which are mounted bearing pads. The resilience of the beam mount causes the pads to accept the load and, with proper design, responds to a rotating thrust-transmitting collar by creating a gas film between the pads and the thrust collar. The bearing may be arranged for load equalization thereby avoiding the necessity of gimbal mounts or the like for the bearing. It may also be arranged to respond to rotation in one or both directions.

  4. Data management implementation plan for the Bear Creek Valley treatability study phase 2 hydraulic performance testing, Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1997-12-01

    The overall objective of the Bear Creek Valley treatability study is to provide site-specific data defining potential treatment technologies applicable to contaminated groundwater and surface water. The ultimate goal of this effort is to install a treatment system that will remove uranium, technetium, nitrate, and several metals from groundwater before it reaches Bear Creek. This project, the Bear Creek Valley treatability study Phase 2 hydraulic performance testing, directly supports the Bear Creek Valley Feasibility Study. Specific project objectives include (1) installing monitoring and extraction wells, (2) installing a groundwater extraction trench, (3) performing pumping tests of the extraction wells and trench, (4) determining hydraulic gradients, and (5) collecting water quality parameters. The primary purpose of environmental data management is to provide a system for generating and maintaining technically defensible data. To meet current regulatory requirements for the Environmental Restoration Program, complete documentation of the information flow must be established. To do so, each step in the data management process (collection, management, storage, and analysis) must be adequately planned and documented. This document will serve to identify data management procedures, expected data types and flow, and roles and responsibilities for all data management activities associated with this project

  5. Rolling bearing analysis

    CERN Document Server

    Harris, Tedric A

    2001-01-01

    One of the most well-known experts in the field brings cutting-edge research to practitioners in the new edition of this important reference. Covers the improved mathematical calculations for rolling bearing endurance developed by the American Society of Mechanical Engineers and the Society of Lubrication and Tribology Engineers. Updated with new material on Condition-Based Maintenance, new testing methods, and new bearing materials.

  6. Analysis of Bearing Capacity Pile Foundation with Using Capwap Software for Testing Pile Driving Analyzer (pda) at Fasfel Development Project Parlimbungan Ketek Sikara-Kara Mandailing Natal District (north Sumatera)

    Science.gov (United States)

    Oberlyn Simanjuntak, Johan; Suita, Diana

    2017-12-01

    Pile foundation is one type deep foundation that serves to distribute the load of hard soil structure loading which has a high bearing capacity that is located deep enough inside the soil. To determine the bearing capacity of the pile and at the same time control the Calendring results, the Pile Driving Analyzer (PDA) test at 8 pile sections from the 84 point piling section (10% of the number sections), the results were analyzed by CAPWAP SOFTWARE, and the highest bearing capacity of Ru 177 ton and the lowest bearing capacity of 111 tons, is bigger than the plan load which load plans that is 60,9 tons. Finally the PDA safe is bearing bearing capacity of the load planning.

  7. Design and suspension experiments of the full-size active magnetic bearing test rig for the HTR-10GT

    International Nuclear Information System (INIS)

    Lu Qiyue; Shi Lei; Zhao Lei; Yu Suyuan

    2005-01-01

    In this paper, we introduce the fundamental properties of the full-size active magnetic bearing experimental set system (AMB-F), including control unit, data I/O channel, feedback unit and executor. Besides, the 72-hours continuously running experiment of the AMB-F, with special attention to the vibration of stators' shell, is presented. This experiment is designed mainly for validating the total system's stability. It is the basis of further characteristic experiments. (authors)

  8. Hydrostatic and hybrid bearing design

    CERN Document Server

    Rowe, W B

    1983-01-01

    Hydrostatic and Hybrid Bearing Design is a 15-chapter book that focuses on the bearing design and testing. This book first describes the application of hydrostatic bearings, as well as the device pressure, flow, force, power, and temperature. Subsequent chapters discuss the load and flow rate of thrust pads; circuit design, flow control, load, and stiffness; and the basis of the design procedures and selection of tolerances. The specific types of bearings, their design, dynamics, and experimental methods and testing are also shown. This book will be very valuable to students of engineering des

  9. Investigation of mechanical properties of hydrate-bearing pressure core sediments recovered from the Eastern Nankai Trough using transparent acrylic cell triaxial testing system (TACTT-system)

    Science.gov (United States)

    Yoneda, J.; Masui, A.; Konno, Y.; Jin, Y.; Kida, M.; Suzuki, K.; Nakatsuka, Y.; Tenma, N.; Nagao, J.

    2014-12-01

    Natural gas hydrate-bearing pressure core sediments have been sheared in compression using a newly developed Transparent Acrylic Cell Triaxial Testing (TACTT) system to investigate the geophysical and geomechanical behavior of sediments recovered from the deep seabed in the Eastern Nankai Trough, the first Japanese offshore production test region. The sediments were recovered by hybrid pressure core system (hybrid PCS) and pressure cores were cut by pressure core analysis tools (PCATs) on board. These pressure cores were transferred to the AIST Hokkaido centre and trimmed by pressure core non-destructive analysis tools (PNATs) for TACTT system which maintained the pressure and temperature conditions within the hydrate stability boundary, through the entire process of core handling from drilling to the end of laboratory testing. An image processing technique was used to capture the motion of sediment in a transparent acrylic cell, and digital photographs were obtained at every 0.1% of vertical strain during the test. Analysis of the optical images showed that sediments with 63% hydrate saturation exhibited brittle failure, although nonhydrate-bearing sediments exhibited ductile failure. In addition, the increase in shear strength with hydrate saturation increase of natural gas hydrate is in agreement with previous data from synthetic gas hydrate. This research was financially supported by the Research Consortium for Methane Hydrate Resources in Japan (MH21 Research Consortium) that carries out Japan's Methane Hydrate R&D Program by the Ministry of Economy, Trade and Industry (METI).

  10. Hydrodynamic bearings

    CERN Document Server

    Bonneau, Dominique; Souchet, Dominique

    2014-01-01

    This Series provides the necessary elements to the development and validation of numerical prediction models for hydrodynamic bearings. This book describes the rheological models and the equations of lubrication. It also presents the numerical approaches used to solve the above equations by finite differences, finite volumes and finite elements methods.

  11. Bearing structures

    International Nuclear Information System (INIS)

    Lee, A.S.; Preece, G.E.

    1988-01-01

    A hydrostatic bearing for the lower end of the vertical shaft of a sodium pump comprises a support shell encircling the shaft and a bush located between the shell and shaft. Liquid sodium is fed from the pump outlet to the bush/shaft and bush/shell interfaces to provide hydrostatic support. The bush outer surface and the shell inner surface are of complementary part-spherical shape and the bush floats relative to the shaft so that the bush can align itself with the shaft axis. Monitoring of the relative rotational speed of the bush with respect to the shaft (such rotation being induced by the viscous drag forces present) is also performed for the purposes of detecting abnormal operation of the bearing or partial seizure, at least one magnet is rotatable with the bush, and a magnetic sensor provides an output having a frequency related to the speed of the bush. (author)

  12. Camshaft bearing arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Aoi, K.; Ozawa, T.

    1986-06-10

    A bearing arrangement is described for the camshaft of an internal combustion engine or the like which camshaft is formed along its length in axial order with a first bearing surface, a first cam lobe, a second bearing surface, a second cam lobe, a third bearing surface, a third cam lobe and a fourth bearing surface, the improvement comprising first bearing means extending around substantially the full circumference of the first bearing surface and journaling the first bearing surface, second bearing means extending around substantially less than the circumference of the second bearing surface and journaling the second bearing surface, third bearing means extending around substantially less than the circumference of the third bearing surface and journaling the third bearing surface, and fourth bearing means extending around substantially the full circumference of the fourth bearing surface and journaling the first bearing surface.

  13. Gas Lubricated Foil Bearing Development for Advanced Turbomachines

    Science.gov (United States)

    1977-03-01

    Rear Journal Bearing Runner 29 3.1.6 Forward Journal Bearing Runner Stress and DefJection Analysis 32 3.1.7 Critical Speed Analysis 35 3.1.8 Thermal...Analysis 39 3.1.8.1 Journal Bearing Temperatures 42 3.1.8.2 Thrust Bearing Temperatures 50 3.2 Design 56 3.2.1 Baseline Bearing Design 56 3.2.1.1 Journal ... Bearing Baseline Design 57 3.2.1.2 Thrust Bearing Baseline Design 59 3.2.2 Thrust Bearing Test Rig Design 61 3.2.3 Journal Bearing Test Rig Design 63

  14. High-resolution well-log derived dielectric properties of gas-hydrate-bearing sediments, Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

    Science.gov (United States)

    Sun, Y.; Goldberg, D.; Collett, T.; Hunter, R.

    2011-01-01

    A dielectric logging tool, electromagnetic propagation tool (EPT), was deployed in 2007 in the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well (Mount Elbert Well), North Slope, Alaska. The measured dielectric properties in the Mount Elbert well, combined with density log measurements, result in a vertical high-resolution (cm-scale) estimate of gas hydrate saturation. Two hydrate-bearing sand reservoirs about 20 m thick were identified using the EPT log and exhibited gas-hydrate saturation estimates ranging from 45% to 85%. In hydrate-bearing zones where variation of hole size and oil-based mud invasion are minimal, EPT-based gas hydrate saturation estimates on average agree well with lower vertical resolution estimates from the nuclear magnetic resonance logs; however, saturation and porosity estimates based on EPT logs are not reliable in intervals with substantial variations in borehole diameter and oil-based invasion.EPT log interpretation reveals many thin-bedded layers at various depths, both above and below the thick continuous hydrate occurrences, which range from 30-cm to about 1-m thick. Such thin layers are not indicated in other well logs, or from the visual observation of core, with the exception of the image log recorded by the oil-base microimager. We also observe that EPT dielectric measurements can be used to accurately detect fine-scale changes in lithology and pore fluid properties of hydrate-bearing sediments where variation of hole size is minimal. EPT measurements may thus provide high-resolution in-situ hydrate saturation estimates for comparison and calibration with laboratory analysis. ?? 2010 Elsevier Ltd.

  15. Application of the Split Hopkinson Resonant Bar Test for Seismic Property Characterization of Hydrate-bearing Sand Undergoing Water Saturation

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, S.; Kneafsey, T.J.

    2011-05-03

    Conventional resonant bar tests allow the measurement of seismic properties of rocks and sediments at low frequencies (several kilohertz). However, the tests require a long, slender sample which is often difficult to obtain from the deep subsurface and weak and fractured formations. We present an alternative low-frequency measurement technique to the conventional resonant bar tests. This technique involves a jacketed core sample placed between a pair of long, metal extension rods with attached seismic source and receiver—the same geometry as the split Hopkinson pressure bar test for large-strain, dynamic impact experiments. Because of the added length and mass to the sample, the resonance frequency of the entire system can be lowered significantly, compared to the sample alone. The proposed “Split Hopkinson Resonant Bar (SHRB)” test is applied in two steps. In the first step, extension and torsion-mode resonance frequencies and attenuation of the system are measured. Then, numerical inversions for the compressional and shear wave velocities and attenuation are performed. We initially applied the SHRB test to synthetic materials (plastics) for testing its accuracy, then used it for measuring the seismic velocities and attenuation of a rock core containing supercritical CO{sub 2}, and a sediment core while methane hydrate formed in the pore space.

  16. Hydrodynamic squeeze-film bearings for gyroscopes

    Science.gov (United States)

    Chiang, T.; Smith, R. L.

    1970-01-01

    Experimental tests are conducted on squeeze-film bearings by applying electricity to piezoelectric ceramics, causing vibrations at thousands or millions of Hz that are amplified and transmitted to the bearing. Rotor operation through 24,000 rpm without whirl instability proved bearing ability to support rotor weight without hydrodynamic action.

  17. Radium bearing waste disposal

    International Nuclear Information System (INIS)

    Tope, W.G.; Nixon, D.A.; Smith, M.L.; Stone, T.J.; Vogel, R.A.; Schofield, W.D.

    1995-01-01

    Fernald radium bearing ore residue waste, stored within Silos 1 and 2 (K-65) and Silo 3, will be vitrified for disposal at the Nevada Test Site (NTS). A comprehensive, parametric evaluation of waste form, packaging, and transportation alternatives was completed to identify the most cost-effective approach. The impacts of waste loading, waste form, regulatory requirements, NTS waste acceptance criteria, as-low-as-reasonably-achievable principles, and material handling costs were factored into the recommended approach

  18. Effects of intramuscular administration of tiletamine-zolazepam with and without sedative pretreatment on plasma and serum biochemical values and glucose tolerance test results in Japanese black bears (Ursus thibetanus japonicus).

    Science.gov (United States)

    Kamine, Akari; Shimozuru, Michito; Shibata, Haruki; Tsubota, Toshio

    2012-08-01

    To establish a safe anesthetic protocol with little effect on blood biochemical values and IV glucose tolerance test (IVGTT) results in Japanese black bears (Ursus thibetanus japonicus). 16 captive female Japanese black bears (5 to 17 years of age). Bears were randomly assigned to 4 treatment groups (4 bears/group) in which various treatment combinations were administered via blow dart: tiletamine HCl and zolazepam HCl (9 mg/kg) alone (TZ), TZ (6 mg/kg) and acepromazine maleate (0.1 mg/kg), TZ (6 mg/kg) and butorphanol tartrate (0.3 mg/kg), or TZ (3 mg/kg) and medetomidine HCl (40 μg/kg). Glucose injection for the IVGTT was started 130 minutes after TZ administration. Blood samples were obtained before, at, and intermittently after glucose injection for measurement of biochemical variables as well as plasma glucose and serum insulin concentrations during the IVGTT. Rectal temperature, pulse rate, and respiratory rate were assessed every 15 minutes during the experiment. Induction and maintenance of anesthesia were safely achieved with little adverse effect on cardiopulmonary function when each of the 4 anesthetic regimens was used, although mild hypothermia was induced. No difference was evident between treatment groups in blood biochemical values. Blood glucose and insulin concentration profiles during the IVGTT were similar among the bears given TZ, with or without acepromazine or butorphanol, but hyperglycemia and hypoinsulinemia developed in bears given TZ with medetomidine. All 4 anesthetic regimens yielded chemical restraint without affecting clinical and biochemical values in bears, but medetomidine appeared to affect IVGTT results. For this reason, medetomidine should not be used when anesthetizing bears for IVGTTs.

  19. State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics

    Directory of Open Access Journals (Sweden)

    Peter W. Tse

    2017-02-01

    Full Text Available Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To extend bearing diagnostics to bearing prognostics, this paper reports the design of a state space formulation of nonlinear vibration responses collected from a dynamic rotor-bearing system in order to intelligently predict bearing remaining useful life (RUL. Firstly, analyses of nonlinear vibration responses were conducted to construct a bearing health indicator (BHI so as to assess the current bearing health condition. Secondly, a state space model of the BHI was developed to mathematically track the health evolution of the BHI. Thirdly, unscented particle filtering was used to predict bearing RUL. Lastly, a new bearing acceleration life testing setup was designed to collect natural bearing degradation data, which were used to validate the effectiveness of the proposed bearing prognostic method. Results show that the prediction accuracy of the proposed bearing prognostic method is promising and the proposed bearing prognostic method is able to reflect future bearing health conditions.

  20. Electron beam melting of bearing materials

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmied, G.; Schuler, A. (Technische Univ., Vienna (Austria). Inst. fuer Allgemeine Elektrotechnik); Elsinger, G.; Koroschetz, F. (MIBA Gleitlager AG, Laakirchen (Austria)); Tschegg, E.K. (Technische Univ., Vienna (Austria). Inst. fuer Angewandte und Technische Physik)

    1990-06-01

    This paper reports on a surface treatment method for the bearing materials AlSn6 which permits the use of this material without the overlay usually required. Microstructural refinement is achieved by means of a surface melting technique using an electron beam with successive rapid solidification. Extremely fine tin precipitates are formed in the melted surface layer which lead to significantly better tribological properties of the bearing material. Tests compared the tribological properties for AlSn6 bearings treated by the surface melting technique with those of untreated bearings. Whereas all untreated bearings failed by seizure after only 2 h of testing, 30% of the tested bearings which had been surface melted survived the entire testing program without damage.

  1. High frequency circular translation pin-on-disk method for accelerated wear testing of ultrahigh molecular weight polyethylene as a bearing material in total hip arthroplasty.

    Science.gov (United States)

    Saikko, Vesa

    2015-01-21

    The temporal change of the direction of sliding relative to the ultrahigh molecular weight polyethylene (UHMWPE) component of prosthetic joints is known to be of crucial importance with respect to wear. One complete revolution of the resultant friction vector is commonly called a wear cycle. It was hypothesized that in order to accelerate the wear test, the cycle frequency may be substantially increased if the circumference of the slide track is reduced in proportion, and still the wear mechanisms remain realistic and no overheating takes place. This requires an additional slow motion mechanism with which the lubrication of the contact is maintained and wear particles are conveyed away from the contact. A three-station, dual motion high frequency circular translation pin-on-disk (HF-CTPOD) device with a relative cycle frequency of 25.3 Hz and an average sliding velocity of 27.4 mm/s was designed. The pins circularly translated at high frequency (1.0 mm per cycle, 24.8 Hz, clockwise), and the disks at low frequency (31.4mm per cycle, 0.5 Hz, counter-clockwise). In a 22 million cycle (10 day) test, the wear rate of conventional gamma-sterilized UHMWPE pins against polished CoCr disks in diluted serum was 1.8 mg per 24 h, which was six times higher than that in the established 1 Hz CTPOD device. The wear mechanisms were similar. Burnishing of the pin was the predominant feature. No overheating took place. With the dual motion HF-CTPOD method, the wear testing of UHMWPE as a bearing material in total hip arthroplasty can be substantially accelerated without concerns of the validity of the wear simulation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1991-01-01

    This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial-stress-shear-strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of FBR plants. It also discusses the protection method against aging and the quality control which are important for implementation. (orig./HP)

  3. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1989-01-01

    This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial stress-shear strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of fast breeder reactor (FBR) plants. The paper also discusses the protection method against aging and the quality control which are important for implementation

  4. Wave Journal Bearing. Part 2: Experimental Pressure Measurements and Fractional Frequency Whirl Threshold for Wave and Plain Journal Bearings

    Science.gov (United States)

    Walker, James F.; Dimofte, Florin; Addy, Harold E., Jr.

    1995-01-01

    A new hydrodynamic bearing concept, the wave journal bearing, is being developed because it has better stability characteristics than plain journal bearings while maintaining similar load capacity. An analysis code to predict the steady state and dynamic performance of the wave journal bearing is also part of the development. To verify numerical predictions and contrast the wave journal bearing's stability characteristics to a plain journal bearing, tests were conducted at NASA Lewis Research Center using an air bearing test rig. Bearing film pressures were measured at 16 ports located around the bearing circumference at the middle of the bearing length. The pressure measurements for both a plain journal bearing and a wave journal bearing compared favorably with numerical predictions. Both bearings were tested with no radial load to determine the speed threshold for self-excited fractional frequency whirl. The plain journal bearing started to whirl immediately upon shaft start-up. The wave journal did not incur self-excited whirl until 800 to 900 rpm as predicted by the analysis. Furthermore, the wave bearing's geometry limited the whirl orbit to less than the bearing's clearance. In contrast, the plain journal bearing did not limit the whirl orbit, causing it to rub.

  5. Passive magnetic bearing configurations

    Science.gov (United States)

    Post, Richard F [Walnut Creek, CA

    2011-01-25

    A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

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

    Science.gov (United States)

    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.

  7. Improved gas thrust bearings

    Science.gov (United States)

    Anderson, W. J.; Etsion, I.

    1979-01-01

    Two variations of gas-lubricated thrust bearings extend substantially load-carrying range over existing gas bearings. Dual-Action Gas Thrust Bearing's load-carrying capacity is more than ninety percent greater than that of single-action bearing over range of compressibility numbers. Advantages of Cantilever-mounted Thrust Bearing are greater tolerance to dirt ingestion, good initial lift-off characteristics, and operational capability over wide temperature range.

  8. Bear-ly” learning: Limits of abstraction in black bear cognition

    Directory of Open Access Journals (Sweden)

    Jennifer Vonk

    2018-02-01

    Full Text Available We presented two American black bears (Ursus americanus with a serial list learning memory task, and one of the bears with a matching-to-sample task. After extended training, both bears demonstrated some success with the memory task but failed to generalize the overarching rule of the task to novel stimuli. Matching to sample proved even more difficult for our bear to learn. We conclude that, despite previous success in training bears to respond to natural categories, quantity discriminations, and other related tasks, that bears may possess a cognitive limitation with regards to learning abstract rules. Future tests using different procedures are necessary to determine whether this is a limit of bears’ cognitive capacities, or a limitation of the current tasks as presented. Future tests should present a larger number of varying stimuli. Ideally, bears of various species should be tested on these tasks to demonstrate species as well as individual differences.

  9. Experimental Evaluation of Journal Bearing Stability and New Gas Bearing Material

    Science.gov (United States)

    Keith, Theo G., Jr.; Dimofte, Florin

    2001-01-01

    It has been estimated that the noise levels in aircraft engine transmissions can be reduced by as much as 10 dB through the use of journal bearings. The potential benefits of lower noise levels include reduced wear, longer gear life and enhanced comfort for passengers and crew. Based on this concept the journal-thrust wave bearing was analyzed and its performance was evaluated. Numerical codes, developed over the past 30 years by Dr. Dimofte, were used to predict the performance of the bearing. The wave bearing is a fluid film bearing and therefore was analyzed using the Reynolds pressure equation. The formulation includes turbulent flow concepts and possesses a viscosity-temperature correction. The centrifugal growth of the bearing diameter and the deformation of the bearing under gear loads were also incorporated into the code. An experimental rig was developed to test the journal-thrust wave bearing.

  10. Superconductor bearings, flywheels and transportation

    Science.gov (United States)

    Werfel, F. N.; Floegel-Delor, U.; Rothfeld, R.; Riedel, T.; Goebel, B.; Wippich, D.; Schirrmeister, P.

    2012-01-01

    This paper describes the present status of high temperature superconductors (HTS) and of bulk superconducting magnet devices, their use in bearings, in flywheel energy storage systems (FESS) and linear transport magnetic levitation (Maglev) systems. We report and review the concepts of multi-seeded REBCO bulk superconductor fabrication. The multi-grain bulks increase the averaged trapped magnetic flux density up to 40% compared to single-grain assembly in large-scale applications. HTS magnetic bearings with permanent magnet (PM) excitation were studied and scaled up to maximum forces of 10 kN axially and 4.5 kN radially. We examine the technology of the high-gradient magnetic bearing concept and verify it experimentally. A large HTS bearing is tested for stabilizing a 600 kg rotor of a 5 kWh/250 kW flywheel system. The flywheel rotor tests show the requirement for additional damping. Our compact flywheel system is compared with similar HTS-FESS projects. A small-scale compact YBCO bearing with in situ Stirling cryocooler is constructed and investigated for mobile applications. Next we show a successfully developed modular linear Maglev system for magnetic train operation. Each module levitates 0.25t at 10 mm distance during one-day operation without refilling LN2. More than 30 vacuum cryostats containing multi-seeded YBCO blocks are fabricated and are tested now in Germany, China and Brazil.

  11. Deterioration Assessment of Bridge Rubber Bearings

    OpenAIRE

    Gu, Haosheng; 伊藤, 義人; Itoh, Yoshito

    2005-01-01

    Natural rubber (NR) with lead plugs and high damping rubber (HDR) are often used for base-isolated rubber bearings. However, it is usually known that ageing causes rubber performance to drop. This research is to study the deterioration characteristics of these two kinds of bridge rubber bearings through accelerated thermal oxidation tests. The property variations inside the aged rubber blocks are investigated. For natural rubber bearing, the mechanical properties on the surface change the mos...

  12. Of tests, trochs, shells, and spicules: Development of the basal mollusk Wirenia argentea (Solenogastres and its bearing on the evolution of trochozoan larval key features

    Directory of Open Access Journals (Sweden)

    Wanninger Andreas

    2010-01-01

    Full Text Available Abstract Background The phylogenetic status of the aplacophoran mollusk taxon Solenogastres (Neomeniomorpha is controversially discussed. Some authors propose the clade to represent the most basal branch within Mollusca, while others claim aplacophoran mollusks (Solenogastres and Caudofoveata to be derived. Larval characters are central in these discussions, specifically the larval test (calymma, apical cap, the ontogeny of the epidermal scleritome, and the proposed absence of larval protonephridia. To date, developmental data are available for five solenogaster species, but most reports are incomplete and need confirmation. Results Wirenia argentea deposit small batches of uncleaved embryos that are tightly enclosed by a smooth and transparent egg hull. Cleavage is spiral and unequal. The ciliated larvae hatch about 45 hours after deposition and swim actively in the water column. Within 48-60 hours after hatching they become mushroom-shaped with a pronounced apical cap partly enclosing a posterior trunk. The cells covering the apical cap are large and cleavage arrested. On the apical cap there is a prominent prototrochal band of compound cilia and an apical ciliary tuft and the trunk bears a terminal ciliary band (telotroch. Obscured by the apical cap, a ciliary band originates in the stomodaeal pore and surrounds the trunk. As development is proceeding, the trunk elongates and becomes covered by cuticle with the exception of a ventral ciliary band, the future foot. The larvae have a pair of protonephridia. At 5 days after hatching they begin to settle and within the following 7-9 days the apical cap is gradually reduced. Scattered epidermal sclerites form under the cuticle. Wirenia argentea lack iterated groups of sclerites at any developmental stage. At 40 days after hatching, the postlarvae have a fully developed foregut, but the midgut and hindgut are not yet interconnected. Conclusions Solenogastres develop via a trochophore

  13. Satellite monitoring of black bear.

    Science.gov (United States)

    Craighead, J. J.; Craighead, F. C., Jr.; Varney, J. R.; Cote, C. E.

    1971-01-01

    Description of a feasibility experiment recently performed to test the use of a satellite system for telemetering environmental and physiological data from the winter den of a 'hibernating' black bear, Ursus americanus. The instrumentation procedure and evaluations of the equipment performance and sensory data obtained are discussed in detail.

  14. Bearing Health Assessment Based on Chaotic Characteristics

    Directory of Open Access Journals (Sweden)

    Chen Lu

    2013-01-01

    Full Text Available Vibration signals extracted from rotating parts of machinery carry a lot of useful information about the condition of operating machine. Due to the strong non-linear, complex and non-stationary characteristics of vibration signals from working bearings, an accurate and reliable health assessment method for bearing is necessary. This paper proposes to utilize the selected chaotic characteristics of vibration signal for health assessment of a bearing by using self-organizing map (SOM. Both Grassberger-Procaccia algorithm and Takens' theory are employed to calculate the characteristic vector which includes three chaotic characteristics, such as correlation dimension, largest Lyapunov exponent and Kolmogorov entropy. After that, SOM is used to map the three corresponding characteristics into a confidence value (CV which represents the health state of the bearing. Finally, a case study based on vibration datasets of a group of testing bearings was conducted to demonstrate that the proposed method can reliably assess the health state of bearing.

  15. Reliability, validity, and minimal detectable change of the push-off test scores in assessing upper extremity weight-bearing ability.

    Science.gov (United States)

    Mehta, Saurabh P; George, Hannah R; Goering, Christian A; Shafer, Danielle R; Koester, Alan; Novotny, Steven

    2017-11-01

    Clinical measurement study. The push-off test (POT) was recently conceived and found to be reliable and valid for assessing weight bearing through injured wrist or elbow. However, further research with larger sample can lend credence to the preliminary findings supporting the use of the POT. This study examined the interrater reliability, construct validity, and measurement error for the POT in patients with wrist conditions. Participants with musculoskeletal (MSK) wrist conditions were recruited. The performance on the POT, grip isometric strength of wrist extensors was assessed. The shortened version of the Disabilities of the Arm, Shoulder and Hand and numeric pain rating scale were completed. The intraclass correlation coefficient assessed interrater reliability of the POT. Pearson correlation coefficients (r) examined the concurrent relationships between the POT and other measures. The standard error of measurement and the minimal detectable change at 90% confidence interval were assessed as measurement error and index of true change for the POT. A total of 50 participants with different elbow or wrist conditions (age: 48.1 ± 16.6 years) were included in this study. The results of this study strongly supported the interrater reliability (intraclass correlation coefficient: 0.96 and 0.93 for the affected and unaffected sides, respectively) of the POT in patients with wrist MSK conditions. The POT showed convergent relationships with the grip strength on the injured side (r = 0.89) and the wrist extensor strength (r = 0.7). The POT showed smaller standard error of measurement (1.9 kg). The minimal detectable change at 90% confidence interval for the POT was 4.4 kg for the sample. This study provides additional evidence to support the reliability and validity of the POT. This is the first study that provides the values for the measurement error and true change on the POT scores in patients with wrist MSK conditions. Further research should examine the

  16. INVESTIGATION OF SHALLOW FOUNDATION SOIL BEARING ...

    African Journals Online (AJOL)

    This study investigated the soil bearing capacity and foundation settlement characteristics of Minna City Centre development site using standard penetration test (SPT) data obtained from10 SPT boreholes at 0.6, 2.1 and 3.6 m depths to correlate soil properties. Evaluation of foundation bearing capacity and settlement ...

  17. Friction coefficients of PTFE bearing liner

    Science.gov (United States)

    Daniels, C. M.

    1979-01-01

    Data discusses frictional characteristics of PTFE (polytetrafluoroethylene) under temperature extremes and in vacuum environment. Tests were also run on reduced scale hardware to determine effects of vacuum. Data is used as reference by designers of aircraft-control system rod-end bearings and for bearings used in polar regions.

  18. BEARING ANALYSIS FOR THE SPUR TURBOGENERATOR.

    Science.gov (United States)

    The results of the analysis of journal bearing configuration for the SPUR turbogenerator are presented in this report. For this analysis, a computer...laminar analysis agreed with existing solutions, thereby providing a check of the computer program. Several journal bearing mounting arrangements were considered, and a design was selected for initial testing. (Author)

  19. Failure of GIMBAL bearing in directional GYRO

    International Nuclear Information System (INIS)

    Pervaiz, R.; Baig, N.A.; Shahid, M.; Ahmad, A.; Chohan, G.Y.

    2003-01-01

    This paper relates to the directional gyro of a sensing device used in indigenously developed surface-to-surface missile. The assembling of more than one thousand components in the form of several sub assemblies including hundreds of silver solders of this device was done in the hundred-thousands-class clean room according to assembly procedure. Whereas more than twenty bearings including gimbals bearings were assembled in the ten-thousands-class clean room after inspection/ testing them on beating testing system as per routine. The device was entered in testing and adjustment phase after successful completion of assembly work. The directional gyro qualified all the tests except the most critical one, the drift-rate. The drift-rate of outer gimbal was 60% more than permissible limit whereas drift-rate of inner gimbal was found O.K. It was diagnosed that at least one inner gimbal bearing out of two had some problem. The results were same after rebalancing of gimbals three times. The directional gyro was disassembled in clean room and the radial-thrust-bearing was recovered and flange bearing which are inner gimbal bearings. They were checked on bearing testing system and it was found that flange-bearing had more friction than permissible limit and hence rejected but radial thrust bearing were declared O.K. The gyro was reassembled with new O.K. flange bearing and the assembly work was completed in all respects. The sensing device qualified all the tests including the drift-rate. This case study is being presented to emphasize the importance of careful assembly of gyro in clean environment. (author)

  20. Teddy Bear Stories

    DEFF Research Database (Denmark)

    van Leeuwen, Theo; Caldas-Coulthardt, Carmen

    2014-01-01

    This paper presents a semiotic analysis of a key cultural artefact, the teddy bear. After introducing the iconography of the teddy bear, it analyses different kinds of stories to show how teddy bears are endowed with meaning in everyday life: stories from children's books, reminiscenses by adults...... about their childhood teddy bears, and children's accounts of what they do with teddy bears, both written for school and told 'out of school', The chapter sees teddy bears as artefacts that provide a cultural channeling for the child's need of a transitional object and argues that the meanings of teddy...... bears have traditionally centred on interpersonal relations within the nuclear family, but have recently been institutionalized and commercialized....

  1. Three-D CFD Analysis of Hydrostatic Bearings

    Science.gov (United States)

    Lin, Shyi-Jang; Hibbs, Robert I., Jr.

    1993-01-01

    The hydrostatic bearing promises life and speed characteristics currently unachievable with rolling element bearings alone. In order to achieve the speed and life requirements of the next generation of rocket engines, turbopump manufacturers are proposing hydrostatic bearings to be used in place of, or in series with, rolling element bearings. The design of a hydrostatic bearing is dependent on accurate pressure in the bearing. The stiffness and damping of the hydrostatic bearing is very sensitive to the bearing recess pressure ratio. In the conventional approach, usually ad hoc assumptions were made in determining the bearing pressure of this approach is inherently incorrect. In the present paper, a more elaborate approach to obtain bearing pressure is used. The bearing pressure and complete flow features of the bearing are directly computed by solving the complete 3-D Navier Stokes equation. The code used in the present calculation is a modified version of REACT3D code. Several calculations have been performed for the hydrostatic bearing designed and tested at Texas A&M. Good agreement has been obtained between computed and test results. Detailed flow features in the bearing will also be described and discussed.

  2. Qualification of high damping seismic isolation bearings for the ALMR

    International Nuclear Information System (INIS)

    Tajirian, F.F.; Gluekler, E.L.; Chen, W.P.; Kelly, J.M.

    1992-01-01

    The Advanced Liquid Metal Reactor (ALMR) seismic isolation system consists of high damping steel-laminated elastomeric bearings. This type of bearing is used worldwide to isolate buildings and large critical components. A comprehensive testing program has been developed to qualify the use of this system for the ALMR. The program includes material characterization tests, various scale bearing tests, full-size bearing tests, shake table tests, and long-term aging tests. The main tasks and objectives of this program are described in the paper. Additionally, a detailed assessment of completed ALMR bearing test results will be provided. This assessment will be mainly based on half-scale bearing tests performed at the Earthquake Engineering Research Center (EERC) of the University of California at Berkeley and at the Energy Technology Engineering Center (ETEC). These tests were funded by the U.S. Department of Energy (DOE). Both static and dynamic tests were performed. Bearings with two types of end connections were tested: dowelled and bolted. The parameters examined will include the vertical, horizontal stiffness and damping of the bearings under different loading conditions up to failure. This will determine the available margins in the bearings above the design vertical load and horizontal displacement. Additionally, the self-centering capability of the bearings after an earthquake will be addressed. On the basis of these findings, recommendations can be made if necessary, to improve current manufacturing procedures, quality control, and procurement specifications. (author)

  3. Vibration model of rolling element bearings in a rotor-bearing system for fault diagnosis

    Science.gov (United States)

    Cong, Feiyun; Chen, Jin; Dong, Guangming; Pecht, Michael

    2013-04-01

    Rolling element bearing faults are among the main causes of breakdown in rotating machines. In this paper, a rolling bearing fault model is proposed based on the dynamic load analysis of a rotor-bearing system. The rotor impact factor is taken into consideration in the rolling bearing fault signal model. The defect load on the surface of the bearing is divided into two parts, the alternate load and the determinate load. The vibration response of the proposed fault signal model is investigated and the fault signal calculating equation is derived through dynamic and kinematic analysis. Outer race and inner race fault simulations are realized in the paper. The simulation process includes consideration of several parameters, such as the gravity of the rotor-bearing system, the imbalance of the rotor, and the location of the defect on the surface. The simulation results show that different amplitude contributions of the alternate load and determinate load will cause different envelope spectrum expressions. The rotating frequency sidebands will occur in the envelope spectrum in addition to the fault characteristic frequency. This appearance of sidebands will increase the difficulty of fault recognition in intelligent fault diagnosis. The experiments given in the paper have successfully verified the proposed signal model simulation results. The test rig design of the rotor bearing system simulated several operating conditions: (1) rotor bearing only; (2) rotor bearing with loader added; (3) rotor bearing with loader and rotor disk; and (4) bearing fault simulation without rotor influence. The results of the experiments have verified that the proposed rolling bearing signal model is important to the rolling bearing fault diagnosis of rotor-bearing systems.

  4. Bearings: Technology and needs

    Science.gov (United States)

    Anderson, W. J.

    1982-01-01

    A brief status report on bearing technology and present and near-term future problems that warrant research support is presented. For rolling element bearings a material with improved fracture toughness, life data in the low Lambda region, a comprehensive failure theory verified by life data and incorporated into dynamic analyses, and an improved corrosion resistant alloy are perceived as important needs. For hydrodynamic bearings better definition of cavitation boundaries and pressure distributions for squeeze film dampers, and geometry optimization for minimum power loss in turbulent film bearings are needed. For gas film bearings, foil bearing geometries that form more nearly optimum film shapes for maximum load capacity, and more effective surface protective coatings for high temperature operation are needed.

  5. Polar bears, Ursus maritimus

    Science.gov (United States)

    Rode, Karyn D.; Stirling, Ian

    2017-01-01

    Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the southernmost extent of seasonal pack ice.

  6. EcoBears

    DEFF Research Database (Denmark)

    Nielsen, Nick; Pedersen, Sandra Bleuenn; Sørensen, Jens Ager

    2015-01-01

    In this paper, we introduce the EcoBears concept that aims to augment household appliances with functional and aesthetic features to promote their "use'' and "longevity of use'' to prevent their disposal. The EcoBears also aim to support the communication of environmental issues in the home setting....... We present our initial design and implementation of the EcoBears that consist of two bear modules (a mother and her cub). We also present our preliminary concept validations and lessons learned to be considered for future directions....

  7. Experimental Study and Dynamic Modeling of Metal Rubber Isolating Bearing

    International Nuclear Information System (INIS)

    Zhang, Ke; Zhou, Yanguo; Jiang, Jian

    2015-01-01

    In this paper, dynamic shear mechanical properties of a new metal rubber isolating bearing is tested and studied. The mixed damping model is provided for theoretical modeling of MR isolating bearing, the shear stiffness and damping characteristics of the MR bearing can be analyzed separately and easily discussed, and the mixed damping model is proved to be an rather effective approach. The test results indicate that loading frequency bears little impact over shear property of metal rubber isolating bearing, the total energy consumption of metal rubber isolating bearing increases with the increase in loading amplitude. With the increase in loading amplitude, the stiffness of the isolating bearing will reduce showing its “soft property”; and the type of damping force gradually changes to be close to dry friction. The features of “soft property” and dry friction energy consumption of metal rubber isolating bearing are very useful in practical engineering application. (paper)

  8. Trichinella surveillance in black bears (Ursus americanus) from Oregon, USA.

    Science.gov (United States)

    Mortenson, J A; Kent, M L; Fowler, D R; Chomel, B B; Immell, D A

    2014-01-01

    We used serology and muscle digestion to test black bears (Ursus americanus) from western Oregon, USA, for Trichinella. Results indicate black bears in Oregon are not part of a sylvatic cycle for Trichinella, and risk of human exposure to Trichinella larvae from eating black bear meat from Oregon appears low.

  9. Foil Bearing Coating Behavior in CO2

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Matthew [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Kruizenga, Alan Michael [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Pasch, James Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fleming, Darryn [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-08-01

    The Sandia S-CO2 Recompression Closed Brayton Cycle (RCBC) utilizes a series of gas foil bearings in its turbine-alternator-compressors. At high shaft rotational speed these bearings allow the shaft to ride on a cushion of air. Conversely, during startup and shutdown, the shaft rides along the foil bearing surface. Low-friction coatings are used on bearing surfaces in order to facilitate rotation during these periods. An experimental program was initiated to elucidate the behavior of coated bearing foils in the harsh environments of this system. A test configuration was developed enabling long duration exposure tests, followed by a range of analyses relevant to their performance in a bearing. This report provides a detailed overview of this work. The results contained herein provide valuable information in selecting appropriate coatings for more advanced future bearing-rig tests at the newly established test facility in Sandia-NM.

  10. Trends in Controllable Oil Film Bearings

    DEFF Research Database (Denmark)

    Santos, Ilmar

    2011-01-01

    This work gives an overview about the theoretical and experimental achievements of mechatronics applied to oil film bearings, with the aim of: controlling the lateral vibration of flexible rotating shafts; modifying bearing dynamic characteristics, as stiffness and damping properties; increasing...... the rotational speed ranges by improving damping and eliminating instability problems, for example, by compensating cross-coupling destabilizing effects; reducing startup torque and energy dissipation in bearings; compensating thermal effects. It is shown that such controllable bearings can act as "smart......" components and be applied to rotating machines with the goal of avoiding unexpected stops of plants, performing rotordynamic tests and identifying model parameters "on site". Emphasis is given to the controllable lubrication (active lubrication) applied to different types of oil film bearings, i...

  11. Rolling Bearing Life Prediction, Theory, and Application

    Science.gov (United States)

    Zaretsky, Erwin V.

    2016-01-01

    A tutorial is presented outlining the evolution, theory, and application of rolling-element bearing life prediction from that of A. Palmgren, 1924; W. Weibull, 1939; G. Lundberg and A. Palmgren, 1947 and 1952; E. Ioannides and T. Harris, 1985; and E. Zaretsky, 1987. Comparisons are made between these life models. The Ioannides-Harris model without a fatigue limit is identical to the Lundberg-Palmgren model. The Weibull model is similar to that of Zaretsky if the exponents are chosen to be identical. Both the load-life and Hertz stress-life relations of Weibull, Lundberg and Palmgren, and Ioannides and Harris reflect a strong dependence on the Weibull slope. The Zaretsky model decouples the dependence of the critical shear stress-life relation from the Weibull slope. This results in a nominal variation of the Hertz stress-life exponent. For 9th- and 8th-power Hertz stress-life exponents for ball and roller bearings, respectively, the Lundberg-Palmgren model best predicts life. However, for 12th- and 10th-power relations reflected by modern bearing steels, the Zaretsky model based on the Weibull equation is superior. Under the range of stresses examined, the use of a fatigue limit would suggest that (for most operating conditions under which a rolling-element bearing will operate) the bearing will not fail from classical rolling-element fatigue. Realistically, this is not the case. The use of a fatigue limit will significantly overpredict life over a range of normal operating Hertz stresses. (The use of ISO 281:2007 with a fatigue limit in these calculations would result in a bearing life approaching infinity.) Since the predicted lives of rolling-element bearings are high, the problem can become one of undersizing a bearing for a particular application. Rules had been developed to distinguish and compare predicted lives with those actually obtained. Based upon field and test results of 51 ball and roller bearing sets, 98 percent of these bearing sets had acceptable

  12. Experimental evaluation of foil-supported resilient-pad gas-lubricated thrust bearing

    Science.gov (United States)

    Nemeth, Z. N.

    1977-01-01

    A new type of resilient-pad gas thrust bearing was tested to determine the feasibility of the design. The bearing consists of carbon graphite pads mounted asymmetrically on foil beams. Two bearing configurations were tested at thrust loads from 27 to 80 newtons at speeds to 9000 rpm. The outside diameter of the bearing was 8.9 centimeters.

  13. Performance of gas-lubricated nonconforming pivoted-pad journal bearings and a flexibly mounted spiral-groove thrust bearing

    Science.gov (United States)

    Ream, L. W.

    1973-01-01

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

  14. On Controllable Elastohydrodynamic Fluid Film Bearings

    DEFF Research Database (Denmark)

    Haugaard, Martin Asger

    This thesis gives a theoretical description of the active tilting-pad journal bearing (ATPJB). It provides the qualified reader with the tools to model an ATPJB, while staying clear of pitfalls. The model is based on well known techniques and allows for local stability analyses, harmonic stationary...... are performed for a tilting-pad journal bearing (TPJB) and an ATPJB under static conditions, followed by a generalisation to dynamic conditions (transient as well as stationary harmonic). These analyses will be of interest to experimentalists, since they permit experiments performed on scaled down test rigs...... the addition of a control system may just as well harm rotor-bearing performance as improve it....

  15. Bearings for the HFIR control plates

    International Nuclear Information System (INIS)

    Abbatiello, A.A.

    1975-08-01

    Recent accelerated wear of HFIR bearings seems to be a more advanced stage of the situation encountered in 1967. The latest observations are in agreement with the hypothesis that high-frequency impact loads at a 30 0 angle on these bearings are the apparent basic cause of their short life. In view of the limited possibilities for change at this stage of HFIR operation, the region of best payoff seems to be an increase in the load-carrying area at some acceptable sacrifice of low rolling friction. On this basis three types of bearings are proposed for test--two of these are journal types and one is a slider type. The next planned shutdown for major parts replacement provides an opportunity to test these modified bearing types in the HFIR under full mechanical operating conditions but without nuclear operation. The program is recommended for consideration and adoption. (U.S.)

  16. Ultra-precision bearings

    CERN Document Server

    Wardle, F

    2015-01-01

    Ultra-precision bearings can achieve extreme accuracy of rotation, making them ideal for use in numerous applications across a variety of fields, including hard disk drives, roundness measuring machines and optical scanners. Ultraprecision Bearings provides a detailed review of the different types of bearing and their properties, as well as an analysis of the factors that influence motion error, stiffness and damping. Following an introduction to basic principles of motion error, each chapter of the book is then devoted to the basic principles and properties of a specific type of bearin

  17. Analysis of bearing steel exposed to rolling contact fatigue

    DEFF Research Database (Denmark)

    Hansen, K. T.; Fæster, Søren; Natarajan, Anand

    2017-01-01

    The objective of this work is to characterize fatigue damage in roller bearings under conditions of high load and slippage. A test rig constructed for rolling contact fatigue tests of rings is described, and test results are presented for rings taken from two spherical roller bearings...

  18. Investigation of Bearing Technology

    National Research Council Canada - National Science Library

    Maciag, Walter

    1998-01-01

    .... They eliminate roller needles and balls in bearings. Since the GC design does not require lubrication maintenance, there is no need for the u-joint cross to contain lubrication reservoirs and distribution channels and their input fitting...

  19. DW_BEAR

    Data.gov (United States)

    Department of Homeland Security — Subset of BEAR (Bi-Weekly Examination Analysis and Reporting) data used for financial audit remediation reporting within the Coast Guard Business Intelligence (CGBI)...

  20. Gear bearing drive

    Science.gov (United States)

    Weinberg, Brian (Inventor); Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  1. Load responsive hydrodynamic bearing

    Science.gov (United States)

    Kalsi, Manmohan S.; Somogyi, Dezso; Dietle, Lannie L.

    2002-01-01

    A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

  2. Studies on Automobile Clutch Release Bearing Characteristics with Acoustic Emission

    Science.gov (United States)

    Chen, Guoliang; Chen, Xiaoyang

    Automobile clutch release bearings are important automotive driveline components. For the clutch release bearing, early fatigue failure diagnosis is significant, but the early fatigue failure response signal is not obvious, because failure signals are susceptible to noise on the transmission path and to working environment factors such as interference. With an improvement in vehicle design, clutch release bearing fatigue life indicators have increasingly become an important requirement. Contact fatigue is the main failure mode of release rolling bearing components. Acoustic emission techniques in contact fatigue failure detection have unique advantages, which include highly sensitive nondestructive testing methods. In the acoustic emission technique to detect a bearing, signals are collected from multiple sensors. Each signal contains partial fault information, and there is overlap between the signals' fault information. Therefore, the sensor signals receive simultaneous source information integration is complete fragment rolling bearing fault acoustic emission signal, which is the key issue of accurate fault diagnosis. Release bearing comprises the following components: the outer ring, inner ring, rolling ball, cage. When a failure occurs (such as cracking, pitting), the other components will impact damaged point to produce acoustic emission signal. Release bearings mainly emit an acoustic emission waveform with a Rayleigh wave propagation. Elastic waves emitted from the sound source, and it is through the part surface bearing scattering. Dynamic simulation of rolling bearing failure will contribute to a more in-depth understanding of the characteristics of rolling bearing failure, because monitoring and fault diagnosis of rolling bearings provide a theoretical basis and foundation.

  3. Spatial transposition tasks in Indian sloth bears (Melursus ursinus) and Bornean sun bears (Helarctos malayanus euryspilus).

    Science.gov (United States)

    Hartmann, Daniela; Davila-Ross, Marina; Wong, Siew Te; Call, Josep; Scheumann, Marina

    2017-11-01

    Spatial transposition tasks assess individuals' ability to represent nonvisible spatial object displacements. Several nonhuman mammal species have been tested on this task including primates, cats, and dogs, but to date, great apes seem the only taxon that has repeatedly and consistently solved spatial transposition tasks. The authors investigated the ability of captive sloth and sun bears to solve spatial transposition tasks. Both species belong to the same taxonomic group as cats and dogs, but unlike them and similar to apes, they have an omnivorous diet that requires them to keep track of fruit sources in space and time. The bears were first tested on a visible displacement task and those that succeeded were further tested on a spatial transposition task that involved a 180° transposition, followed by 2 tasks with two 360° transpositions. All 7 sloth bears and 7 out of 9 sun bears solved the visible displacement task. The 180° transposition task was solved by 6 out of 7 sloth bears and 1 out of the 5 tested sun bears. Three sloth bears were tested on all 4 experiments and even solved 2-chained 360° transpositions. Control conditions were conducted showing that the bears' performance did not rely on olfactory or auditory cues. The results provide the first indication that bears might be able to track invisible objects. Further studies will be necessary to confirm these results and to control the influence of associative learning. The present study emphasizes the importance of including different animal species in the investigation of what underlies the evolution of different cognitive skills. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  4. Compatibility of preparatory procedures for the analysis of cortisol concentrations and stable isotope (δ13C, δ15N) ratios: a test on brown bear hair

    Science.gov (United States)

    Sergiel, Agnieszka; Hobson, Keith A.; Janz, David M.; Cattet, Marc; Selva, Nuria; Kapronczai, Luciene; Gryba, Chantel

    2017-01-01

    Abstract The measurement of naturally occurring glucocorticoids and stable isotopes of several elements has gained importance in wildlife studies in recent decades and opened a myriad of ecological applications. Cortisol and stable isotopes equilibrate in animal tissues over periods of integration related to the growth rate of the tissue, providing information reflecting systemic cortisol secretion and dietary intake. Sample preparation shares the common step of first cleaning the sample of external contamination. However, it is not well understood how different solvents used in sample preparation affect isotopic and cortisol values, and whether it is safe to follow the same procedures for both measures to optimize analyses of the same sample. We conducted an experiment to compare different preparation protocols for the analysis of cortisol concentrations and stable carbon (δ13C) and nitrogen (δ15N) isotope ratios in hair. Hair samples from 12 brown bears (Ursus arctos) were each divided into five aliquots; two aliquots were rinsed with a 2:1 chloroform:methanol (v/v) mixture with one aliquot ground prior to cortisol analysis and the other left intact for stable isotope analyses; two aliquots were washed with methanol with one aliquot ground prior to cortisol analysis and the other left intact for stable isotope analyses; and one aliquot washed with methanol and ground prior to stable isotope analyses. The cortisol, δ13C and δ15N values remained consistent following all treatments. Our results indicate that hair samples rinsed with a 2:1 chloroform:methanol mixture or washed with methanol can be used for both types of analyses. Further, hair that has been ground in a standard hair cortisol procedure can also be used for stable isotope analysis. This information is important for improving laboratory efficiency and compatibility of procedures used for wildlife physiological ecology studies where concurrent measurements of cortisol and stable isotopes in hair are

  5. AX-5 space suit bearing torque investigation

    Science.gov (United States)

    Loewenthal, Stuart; Vykukal, Vic; Mackendrick, Robert; Culbertson, Philip, Jr.

    1990-01-01

    The symptoms and eventual resolution of a torque increase problem occurring with ball bearings in the joints of the AX-5 space suit are described. Starting torques that rose 5 to 10 times initial levels were observed in crew evaluation tests of the suit in a zero-g water tank. This bearing problem was identified as a blocking torque anomaly, observed previously in oscillatory gimbal bearings. A large matrix of lubricants, ball separator designs and materials were evaluated. None of these combinations showed sufficient tolerance to lubricant washout when repeatedly cycled in water. The problem was resolved by retrofitting a pressure compensated, water exclusion seal to the outboard side of the bearing cavity. The symptoms and possible remedies to blocking are discussed.

  6. Development of hydrodynamic micro-bearings

    Science.gov (United States)

    Wang, P.; Zhang, J.; Spikes, H. A.; Reddyhoff, T.; Holmes, A. S.

    2016-11-01

    This paper describes the modelling and testing of mm-scale hydrodynamic bearings which are being developed to improve the efficiency of a cm-scale turbine energy harvester, whose efficiency was previously limited by poorly lubricated commercial jewel-bearings. The bearings were fabricated using DRIE and their performance was assessed using a custom built MEMS tribometer. Results demonstrate that acceptably low friction is achieved when low viscosity liquid lubricants are used in combination with an appropriate choice of friction modifier additive. Further reduction in friction is demonstrated when the step height of bearing is adjusted in accordance with hydrodynamic theory. In parallel with the experiments, hydrodynamic lubricant modelling has been carried out to predict and further optimize film thickness and friction performance. Modelling results are presented and validated against experimental friction data.

  7. Adaptive Spindle Balancing Using Magnetically Levitated Bearings

    International Nuclear Information System (INIS)

    BARNEY, PATRICK S.; LAUFFER, JAMES P.; PETTEYS, REBECCA; REDMOND, JAMES M.; SULLIVAN, WILLIAM N.

    1999-01-01

    A technological break through for supporting rotating shafts is the active magnetic bearing (AMB). Active magnetic bearings offer some important advantages over conventional ball, roller or journal bearings such as reduced frictional drag, no physical contact in the bearing, no need for lubricants, compatibility with high vacuum and ultra-clean environments, and ability to control shaft position within the bearing. The disadvantages of the AMB system are the increased cost and complexity, reduced bearing stiffness and the need for a controller. Still, there are certain applications, such as high speed machining, biomedical devices, and gyroscopes, where the additional cost of an AMB system can be justified. The inherent actuator capabilities of the AMB offer the potential for active balancing of spindles and micro-shaping capabilities for machine tools, The work presented in this paper concentrates on an AMB test program that utilizes the actuator capability to dynamically balance a spindle. In this study, an unbalanced AMB spindle system was enhanced with an LMS (Least Mean Squares) algorithm combined with an existing PID (proportional, integral, differential) control. This enhanced controller significantly improved the concentricity of an intentionally unbalanced shaft. The study included dynamic system analysis, test validation, control design and simulation, as well as experimental implementation using a digital LMS controller

  8. Adaptive Spindle Balancing Using Magnetically Levitated Bearings

    Energy Technology Data Exchange (ETDEWEB)

    BARNEY,PATRICK S.; LAUFFER,JAMES P.; PETTEYS,REBECCA; REDMOND,JAMES M.; SULLIVAN,WILLIAM N.

    1999-09-20

    A technological break through for supporting rotating shafts is the active magnetic bearing (AMB). Active magnetic bearings offer some important advantages over conventional ball, roller or journal bearings such as reduced frictional drag, no physical contact in the bearing, no need for lubricants, compatibility with high vacuum and ultra-clean environments, and ability to control shaft position within the bearing. The disadvantages of the AMB system are the increased cost and complexity, reduced bearing stiffness and the need for a controller. Still, there are certain applications, such as high speed machining, biomedical devices, and gyroscopes, where the additional cost of an AMB system can be justified. The inherent actuator capabilities of the AMB offer the potential for active balancing of spindles and micro-shaping capabilities for machine tools, The work presented in this paper concentrates on an AMB test program that utilizes the actuator capability to dynamically balance a spindle. In this study, an unbalanced AMB spindle system was enhanced with an LMS (Least Mean Squares) algorithm combined with an existing PID (proportional, integral, differential) control. This enhanced controller significantly improved the concentricity of an intentionally unbalanced shaft. The study included dynamic system analysis, test validation, control design and simulation, as well as experimental implementation using a digital LMS controller.

  9. Watchable Wildlife: The Black Bear

    Science.gov (United States)

    Lynn L. Rogers

    1992-01-01

    Black bears are the bears people most often encounter. Black bears live in forests over much of North America, unlike grizzlies that live only in Alaska, northern and western Canada, and the northern Rocky Mountains. This brochure presents the latest information on black bear life and how this species responds to an ever-increasing number of campers, hikers, and...

  10. Climate Drives Polar Bear Origins

    Science.gov (United States)

    In their provocative analysis of northern bears (“Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage,” Reports, 20 April, p. 344), F. Hailer et al. use independent nuclear loci to show that polar bears originated during the middle Pleistocene, rather than during t...

  11. The effect of external dynamic loads on the lifetime of rolling element bearings: accurate measurement of the bearing behaviour

    International Nuclear Information System (INIS)

    Jacobs, W; Boonen, R; Sas, P; Moens, D

    2012-01-01

    Accurate prediction of the lifetime of rolling element bearings is a crucial step towards a reliable design of many rotating machines. Recent research emphasizes an important influence of external dynamic loads on the lifetime of bearings. However, most lifetime calculations of bearings are based on the classical ISO 281 standard, neglecting this influence. For bearings subjected to highly varying loads, this leads to inaccurate estimations of the lifetime, and therefore excessive safety factors during the design and unexpected failures during operation. This paper presents a novel test rig, developed to analyse the behaviour of rolling element bearings subjected to highly varying loads. Since bearings are very precise machine components, their motion can only be measured in an accurately controlled environment. Otherwise, noise from other components and external influences such as temperature variations will dominate the measurements. The test rig is optimised to perform accurate measurements of the bearing behaviour. Also, the test bearing is fitted in a modular structure, which guarantees precise mounting and allows testing different types and sizes of bearings. Finally, a fully controlled multi-axial static and dynamic load is imposed on the bearing, while its behaviour is monitored with capacitive proximity probes.

  12. Chromatographic (TLC) differentiation of grizzly bear and black bear scats

    Science.gov (United States)

    Picton, Harold D.; Kendall, Katherine C.

    1994-01-01

    While past work concluded that thin-layer chromatography (TLC) was inadequate for the separation of grizzly (Ursus arctos horribilis) and black bear (U. americanus) scats, our study found differences adequate for species separation. A key was constructed using 19 of 40 data points recorded on each(N)=356 profiles of 178) know-species scat. Accuracy was best for late summer scats (94%). Methods for specimen preparation, analysis, and reading the TLC profiles are discussed. Factors involved in scat variation were tested.

  13. Experimental study on bearing preload optimum of machine tool spindle

    International Nuclear Information System (INIS)

    Xu Tao; Xu Guanghua; Zhang Qin; Hua Cheng; Zhang Hu; Jiang Kuosheng

    2012-01-01

    An experimental study is conducted to investigate the possibility and the effect of temperature rise and vibration level of bearing by adjusting axial preloads and radial loads in spindle bearing test rig. The shaft of the test rig is driven by a motorized high speed spindle at the range of 0∼20000 rpm. The axial preloads and radial loads on bearings are controlled by using hydraulic pressure which can be adjusted automatically. Temperature rise and radial vibration of test bearings are measured by thermocouples and Polytec portable laser vibrometer PDV100. Experiment shows that the temperature rise of bearings is nonlinear varying with the increase of radial loads, but temperature rise almost increases linearly with the increase of axial preload and rotating speed. In this paper, an alternate axial preload is used for bearings. When the rotating speed passes through the critical speed of the shaft, axial preload of bearings will have a remarkable effect. The low preload could reduce bearing vibration and temperature rise for bearings as well. At the others speed, the high preload could improve the vibration performance of high speed spindle and the bearing temperature was lower than that of the constant pressure preload spindle.

  14. Lubrication of an 85-mm ball bearing with RP-1

    Science.gov (United States)

    Addy, Harold E., Jr.; Schuller, Fredrick T.

    1993-01-01

    A parametric experimental investigation of an 85 millimeter bore angular contact ball bearing running in RP-1 fuel was performed at speeds of 10,000 to 24,000 rpm. Thrust loads were varied from 4450 to 17,800 Newtons (1000 to 4000 lbs.). Radial loads were varied from 1335 to 13,350 Newtons (300 to 3000 lbs.). RP-1 lubrication for the bearing was provided through a stationary jet ring located adjacent to the test bearing outer ring. Increases in both the thrust and radial loads resulted in increased bearing temperature, while increases in shaft speed resulted in much more dramatic increases in bearing temperature. These trends are typical for ball bearings operating under these types of conditions. Results are given for outer ring temperatures of the test bearing at the various test conditions employed. In addition, the heat energy removed from the bearing by the RP-1 was determined by measuring the increase in temperature as the RP-1 passed through the bearing. Results showed that the amount of heat energy removed by the RP-1 increased with both shaft speed and RP-1 flow rate to the bearing.

  15. Radial Halbach Magnetic Bearings

    Science.gov (United States)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2009-01-01

    Radial Halbach magnetic bearings have been investigated as part of an effort to develop increasingly reliable noncontact bearings for future high-speed rotary machines that may be used in such applications as aircraft, industrial, and land-vehicle power systems and in some medical and scientific instrumentation systems. Radial Halbach magnetic bearings are based on the same principle as that of axial Halbach magnetic bearings, differing in geometry as the names of these two types of bearings suggest. Both radial and axial Halbach magnetic bearings are passive in the sense that unlike most other magnetic bearings that have been developed in recent years, they effect stable magnetic levitation without need for complex active control. Axial Halbach magnetic bearings were described in Axial Halbach Magnetic Bearings (LEW-18066-1), NASA Tech Briefs, Vol. 32, No. 7 (July 2008), page 85. In the remainder of this article, the description of the principle of operation from the cited prior article is recapitulated and updated to incorporate the present radial geometry. In simplest terms, the basic principle of levitation in an axial or radial Halbach magnetic bearing is that of the repulsive electromagnetic force between (1) a moving permanent magnet and (2) an electric current induced in a stationary electrical conductor by the motion of the magnetic field. An axial or radial Halbach bearing includes multiple permanent magnets arranged in a Halbach array ("Halbach array" is defined below) in a rotor and multiple conductors in the form of wire coils in a stator, all arranged so the rotary motion produces an axial or radial repulsion that is sufficient to levitate the rotor. A basic Halbach array (see Figure 1) consists of a row of permanent magnets, each oriented so that its magnetic field is at a right angle to that of the adjacent magnet, and the right-angle turns are sequenced so as to maximize the magnitude of the magnetic flux density on one side of the row while

  16. The Development of Open Water-lubricated Polycrystalline Diamond (PCD) Thrust Bearings for Use in Marine Hydrokinetic (MHK) Energy Machines

    Energy Technology Data Exchange (ETDEWEB)

    Cooley, Craig, H.; Khonsari, Michael,, M; Lingwall, Brent

    2012-11-28

    Polycrstalline diamond (PCD) bearings were designed, fabricated and tested for marine-hydro-kinetic (MHK) application. Bearing efficiency and life were evaluated using the US Synthetic bearing test facility. Three iterations of design, build and test were conducted to arrive at the best bearing design. In addition life testing that simulated the starting and stopping and the loading of real MHK applications were performed. Results showed polycrystalline diamond bearings are well suited for MHK applications and that diamond bearing technology is TRL4 ready. Based on life tests results bearing life is estimated to be at least 11.5 years. A calculation method for evaluating the performance of diamond bearings of round geometry was also investigated and developed. Finally, as part of this effort test bearings were supplied free of charge to the University of Alaska for further evaluation. The University of Alaska test program will subject the diamond bearings to sediment laden lubricating fluid.

  17. Gearbox Reliability Collaborative Gearbox 3 Planet Bearing Calibration

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-03-24

    The Gearbox Reliability Collaborative gearbox was redesigned to improve its load-sharing characteristics and predicted fatigue life. The most important aspect of the redesign was to replace the cylindrical roller bearings with preloaded tapered roller bearings in the planetary section. Similar to previous work, the strain gages installed on the planet tapered roller bearings were calibrated in a load frame. This report describes the calibration tests and provides the factors necessary to convert the measured units from dynamometer testing to bearing loads, suitable for comparison to engineering models.

  18. Towards Identification of Rotordynamic Properties for Seals in Multiphase Flow Using Active Magnetic Bearings. Design and Commissioning of a Novel Test Facility

    DEFF Research Database (Denmark)

    Voigt, Andreas Jauernik

    important contact free force measurement capabilities. The third module houses the smooth annular test seals and the fourth module adds a single phase air flow supply to the test facility infrastructure. For experimental identification purposes the ability to acquire precise information of the forces...... and compressors for which reason the ability to predict the complex interaction between fluid dynamics and rotordynamics within these seals is a key aspect in the design of rotating equipment. Numerical tools offering predictive capabilities for seals subjected to multiphase flow conditions are currently being...... developed and refined, however a pronounced lack of experimental data renders benchmarking and validation impossible. This thesis focusses on documenting the design and commissioning of a test facility enabling the much needed experimental identification of rotordynamic properties for turbomachinery seals...

  19. Rotordynamics and bearing design of turbochargers

    Science.gov (United States)

    Chen, Wen Jeng

    2012-05-01

    Turbochargers have gained significant attention in recent years. They are already widely used in automotive, locomotive, and marine applications with diesel engines. They are also applied in the aerospace application to increase the engine performance now. The turbochargers used in automotive and aerospace industry are very light-weight with operating speeds above 100,000 rpm. The turbochargers used in locomotive and marine applications are relatively heavy in size and power compared to the automotive and aerospace applications, and the maximum continuous operating speeds are around 30,000 rpm depending on the diesel engine power rating. Floating ring bushings, semi-floating dampers, ball bearings, and ball bearings with dampers are commonly used in automotive applications for small turbochargers. However, these bearings may not be appropriate for large turbochargers in locomotive and marine applications. Instead, multi-lobed bearings with and without squeeze film dampers are commonly used in these heavy-duty turbochargers. This paper deals with the rotordynamic characteristics of larger turbochargers in locomotive and marine applications. Various bearing designs are discussed. Bearing design parameters are studied and optimal values are suggested. Test results are also presented to support the analytical simulation.

  20. Experimental Evaluation of Journal Bearing Stability and New Gas Wave Bearing Materials

    Science.gov (United States)

    Keith, Theo G., Jr.; Dimofte, Florin

    1998-01-01

    A gas journal bearing, with a wavy surfaces was tested in a range of speeds up to 18,000 RPM to determine its stability in an unloaded condition as a function of the wave amplitude. The bearing, was 50 mm in diameter, 58 mm long and had 0.01 65 mm radial clearance. Three waves were created on the inner surface by deforming the bearing sleeve. The ratio of the wave amplitude to the radial clearance (the wave amplitude ratio) was varied from zero to 0.3.

  1. Research on Bored Bearing Characteristics in Xi’an

    Directory of Open Access Journals (Sweden)

    Zhang Lipeng

    2015-01-01

    Full Text Available To analyze the influence of different soil properties on pile foundation load-bearing characteristics, taking a section of railway in Xi’an and a bridge of Xi’an as test area, and by field static load test to study load transfer characteristics after the test piles under axial pressure, including the distribution of axial force, pile lateral friction, tip resistance traits, ultimate bearing capacity determine, and compare with the theory bearing capacity. Experimental results show that, adjacent soil properties change large, axial force and lateral friction mutation at the junction of corresponding soil layer. Silty clay in different parts is below ground, and its lateral friction plays much difference. Pile lateral friction plays an important role in bearing capacity, but the role of round gravel soil end bearing capacity to pile bearing capacity can’t be ignored. Tests calculate pile bearing capacity significantly larger than standardized formula calculation bearing capacity, which are respectively 55.35% and 119.1%. And give the similar project condition the suggested values of pile bearing capacity and soil friction, to provide reference for similar pile foundation design.

  2. Platelet function in brown bear (Ursus arctos compared to man

    Directory of Open Access Journals (Sweden)

    Särndahl Eva

    2010-06-01

    Full Text Available Abstract Background Information on hemostasis and platelet function in brown bear (Ursus arctos is of importance for understanding the physiological, protective changes during hibernation. Objective The study objective was to document platelet activity values in brown bears shortly after leaving the den and compare them to platelet function in healthy humans. Methods Blood was drawn from immobilized wild brown bears 7-10 days after leaving the den in mid April. Blood samples from healthy human adults before and after clopidogrel and acetylsalicylic acid administration served as control. We analyzed blood samples by standard blood testing and platelet aggregation was quantified after stimulation with various agonists using multiple electrode aggregometry within 3 hours of sampling. Results Blood samples were collected from 6 bears (3 females between 1 and 16 years old and from 10 healthy humans. Results of adenosine diphosphate, aspirin, and thrombin receptor activating peptide tests in bears were all half or less of those in humans. Platelet and white blood cell counts did not differ between species but brown bears had more and smaller red blood cells compared with humans. Conclusion Using three different tests, we conclude that platelet function is lower in brown bears compared to humans. Our findings represent the first descriptive study on platelet function in brown bears and may contribute to explain how bears can endure denning without obvious thrombus building. However, the possibility that our findings reflect test-dependent and not true biological variations in platelet reactivity needs further studies.

  3. Recycling of Zn-containing Fe-bearing steelmaking waste by the reducing smelting process in pig iron. I. Laboratory tests

    Directory of Open Access Journals (Sweden)

    Kendera Ján

    1997-09-01

    Full Text Available Results of the laboratory test treatment of the zinc containing steelwork dusts in a hot liquid pig iron are described. These results show that it is necessary to use an external reductant. The zinc content of the dust emission is ca. 20 %. The charge of the steel-works dusts diminished the Si and Mn content of pig iron.

  4. Gearbox Reliability Collaborative Bearing Calibration

    Energy Technology Data Exchange (ETDEWEB)

    van Dam, J.

    2011-10-01

    NREL has initiated the Gearbox Reliability Collaborative (GRC) to investigate the root cause of the low wind turbine gearbox reliability. The GRC follows a multi-pronged approach based on a collaborative of manufacturers, owners, researchers and consultants. The project combines analysis, field testing, dynamometer testing, condition monitoring, and the development and population of a gearbox failure database. At the core of the project are two 750kW gearboxes that have been redesigned and rebuilt so that they are representative of the multi-megawatt gearbox topology currently used in the industry. These gearboxes are heavily instrumented and are tested in the field and on the dynamometer. This report discusses the bearing calibrations of the gearboxes.

  5. High-performance plain bearings for diesel engines. Hochleistungs-Gleitlager fuer Dieselmotoren

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, R.M.; Mathias, M.; Herrmann, B. (MTU, Friedrichshafen (Germany))

    1992-01-01

    The crankshaft bearings are among the most highly stressed engine components. Conventional plain bearings no longer fulfill the requirements of modern high-performance diesel engines. Introduction of the 'Sputter' technology, as a method of anti friction layer application, opened new perspectives in the field of plain bearing manufacture. In this presentation it is intended to compare various types of plain bearings and to demonstrate operation-oriented bearing testing. (orig.).

  6. Hybrid superconductor magnet bearings

    Science.gov (United States)

    Chu, Wei-Kan

    1995-01-01

    Hybrid superconductor magnet bearings (HSMB's) utilize high temperature superconductors (HTS's) together with permanent magnets to form a frictionless interface between relatively rotating parts. They are low mass, stable, and do not incur expenditure of energy during normal operation. There is no direct physical contact between rotor and stator, and hence there is no wear and tear. However, just as any other applications of HTS's, it requires a very cold temperature to function. Whereas this might be perceived as a disadvantage on earth, it is of no great concern in space or on the moon. To astronomers, the moon is an excellent site for an observatory, but the cold and dusty vacuum environment on the moon precludes the use of mechanical bearings on the telescope mounts. Furthermore, drive mechanisms with very fine steps, and hence bearings with extremely low friction are needed to track a star from the moon, because the moon rotates very slowly. All aspects considered, the HSMB is about the only candidate that fits in naturally. Here, we present a design for one such bearing, capable of supporting a telescope that weighs about 3 lbs on Earth.

  7. Of tests, trochs, shells, and spicules: Development of the basal mollusk Wirenia argentea (Solenogastres) and its bearing on the evolution of trochozoan larval key features

    DEFF Research Database (Denmark)

    Todt, Christiane; Wanninger, Andreas

    2010-01-01

    ) to be derived. Larval characters are central in these discussions, specifically the larval test (calymma, apical cap), the ontogeny of the epidermal scleritome, and the proposed absence of larval protonephridia. To date, developmental data are available for five solenogaster species, but most reports...... are incomplete and need confirmation. RESULTS: Wirenia argentea deposit small batches of uncleaved embryos that are tightly enclosed by a smooth and transparent egg hull. Cleavage is spiral and unequal. The ciliated larvae hatch about 45 hours after deposition and swim actively in the water column. Within 48...... a fully developed foregut, but the midgut and hindgut are not yet interconnected. CONCLUSIONS: Solenogastres develop via a trochophore-like lecitotrophic larva with a preoral apical cap that at least partly represents an enlarged prototrochal area. Homology of this larval type (pericalymma larva) to test...

  8. A Low Friction Thrust Bearing for Reciprocating Compressors

    OpenAIRE

    Nagata, Shuhei; Kousokabe, Hirokatsu; Sekiyama, Nobuya; Ono, Toshiaki

    2012-01-01

    A thrust bearing with a micro texture on its sliding surface that produces hydrodynamic pressure was developed for use in reciprocating compressors. Evaluation using an elemental friction test showed that its friction loss was 20–60 % lower than that of the current design. Measurement of the efficiency of a compressor with the developed thrust bearing showed that the coefficient of performance was 1.4 % higher than that of a compressor with a conventional thrust bearing.

  9. Active Magnetic Bearings – Magnetic Forces

    DEFF Research Database (Denmark)

    Kjølhede, Klaus

    2006-01-01

    Parameter identification procedures and model validation are major steps towards intelligent machines supported by active magnetic bearings (AMB). The ability of measuring the electromagnetic bearing forces, or deriving them from measuring the magnetic flux, strongly contributes to the model...... of the work is the characterization of magnetic forces by using two experimental different experimental approaches. Such approaches are investigated and described in details. A special test rig is designed where the 4 poles - AMB is able to generate forces up to 1900 N. The high precision characterization...... of the magnetic forces are led by using different experimental tests: (I) by using hall sensors mounted directly on the poles (precise measurements of the magnetic flux) and by an auxiliary system, composed of strain gages and flexible beams attached to the rotor; (II) by measuring the input current and bearing...

  10. Identifying lubricant options for compressor bearing designs

    Science.gov (United States)

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

    2017-08-01

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

  11. Compliant hydrodynamic fluid journal bearing

    Science.gov (United States)

    Warren, E. L. (Inventor)

    1985-01-01

    An air bearing structure is described that prevents destructive bending moments within the top foil. Welds are eliminated by mounting the top bearing foil in the bearing cartridge sleeve without using a space block. Tabs or pins at the end of the top bearing foil are restrained by slots or stops formed in the cartridge sleeve. These structural members are free to move in a direction normal to the shaft while being restrained from movement in the direction of shaft rotation.

  12. Magnetic bearing and motor

    Science.gov (United States)

    Studer, Philip A. (Inventor)

    1983-01-01

    A magnetic bearing assembly (10) has an intermediate rotatable section (33) having an outer cylindrical member (30) coaxially suspended by a torsion wire (72) around an axially polarized cylindrical magnet (32). Axial alignment between the pole faces (40-43) of the intermediate section (33) and end surfaces (50-53) of opposed end bells (20, 22) provides a path of least reluctance across intervening air gaps (60-63) for the magnetic flux emanating from magnet (32). Radial dislocation increases the reluctance and creates a radial restoring force. Substitution of radially polarized magnets 107 fixed to a magnetically permeable cylinder (32') and insertion of pairs of armature coil windings (109-112) between the cylinder pair (33') provides an integral magnetic bearing and torsion motor (100) able to provide arcuately limited rotational drive.

  13. Passive magnetic bearing system

    Science.gov (United States)

    Post, Richard F.

    2014-09-02

    An axial stabilizer for the rotor of a magnetic bearing provides external control of stiffness through switching in external inductances. External control also allows the stabilizer to become a part of a passive/active magnetic bearing system that requires no external source of power and no position sensor. Stabilizers for displacements transverse to the axis of rotation are provided that require only a single cylindrical Halbach array in its operation, and thus are especially suited for use in high rotation speed applications, such as flywheel energy storage systems. The elimination of the need of an inner cylindrical array solves the difficult mechanical problem of supplying support against centrifugal forces for the magnets of that array. Compensation is provided for the temperature variation of the strength of the magnetic fields of the permanent magnets in the levitating magnet arrays.

  14. Government Risk-Bearing

    CERN Document Server

    1993-01-01

    The u.s. government bulks large in the nation's financial markets. The huge volume of government-issued and -sponsored debt affects the pricing and volume ofprivate debt and, consequently, resource allocation between competing alternatives. What is often not fully appreciated is the substantial influence the federal government wields overresource allocation through its provisionofcreditandrisk-bearing services to the private economy. Because peopleand firms generally seekto avoid risk, atsomeprice they are willing to pay another party to assume the risk they would otherwise face. Insurance companies are a class of private-sector firms one commonly thinks of as providing these services. As the federal government has expanded its presence in the U.S. economy during this century, it has increasingly developed programs aimed at bearing risks that the private sector either would not take on at any price, or would take on but atapricethoughtto besogreatthatmostpotentialbeneficiarieswouldnotpurchase the coverage. To...

  15. COMPOSITION OF BLACK BEAR MILK.

    Science.gov (United States)

    An analysis of black bear ( Ursus americanus Pallas) milk showed that the total solids, fat and protein were much higher and the lactose lower than...either cow or human milk. In comparison with polar bear (Thalarcotos maritimus ), the black bear milk was lower in fat, protein and total calories. (Author)

  16. Frictionless Bearing Uses Permanent Magnets

    Science.gov (United States)

    1965-01-01

    The purpose of this innovation was to develop a frictionless bearing for high speed, light load applications. The device involves the incorporation of permanent magnets in the bearing design. The repulsion of like magnetic poles provides concentric support of the inner member so that no metallic contact occurs between the bearing surfaces.

  17. Rotating plug bearing and seal

    International Nuclear Information System (INIS)

    Wade, E.E.

    1977-01-01

    Disclosed is a bearing and seal structure for nuclear reactors utilizing rotating plugs above the nuclear reactor vessel. The structure permits lubrication of bearings and seals of the rotating plugs without risk of the lubricant draining into the reactor vessel below. The structure permits lubrication by utilizing a rotating outer race bearing. 19 claims, 3 figures

  18. Interaction of Reinforced Elastomeric Bearings in Bridge Construction

    Directory of Open Access Journals (Sweden)

    Nittmannová Ľubica

    2016-03-01

    Full Text Available The aim of this paper is to demonstrate the behavior of reinforced elastomeric bearings under various loads. They are made of special types of bearings. The experimental verification of these special bearings has been tested on various types of loading. The results of the experimental measurements are compared with the results of the numerical modeling and calculations according to the standard assumptions in STN EN 1337-3. In the conclusion, the results are summarized for the selected types of bearings.

  19. INVESTIGATION OF TRIBOLOGICAL PROPERTIES CuSn10 BEARING MATERIAL

    Directory of Open Access Journals (Sweden)

    Bekir Sadık ÜNLÜ

    2005-01-01

    Full Text Available Bronzes which copper based alloys is widely used because of properties physical, thermal and tribological as journal bearing material. This material that has tribological performance good conclusions gives at journal bearings. In this study, CuSn10 bronze that were manufactured journal bearings friction and wear properties has been examined and compared. SAE 1050 steel shaft has been used as counter abrader. Experiments have been carried out 10 N and 20 N loads, 750 and 1500 rpm, dry and lubricated conditions by using radial journal bearing wear test rig. As a results, high friction coefficient and weigh loss have been obtained at dry condition more than lubricated condition.

  20. Development of a dc motor with virtually zero powered magnetic bearing

    Science.gov (United States)

    1971-01-01

    The development of magnetic bearings for use in direct current electric motors is discussed. The characteristics of the magnets used in the construction of the bearings are described. A magnetic bearing using steel armoring on permanent magnets was selected for performance tests. The specifications of the motor are presented. The test equipment used in the evaluation is described.

  1. Gearbox Instrumentation for the Investigation of Bearing Axial Cracking

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jonathan A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lambert, Scott R [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-03-27

    Failures in gearbox bearings have been the primary source of reliability issues for wind turbine drivetrains, leading to costly downtime and unplanned maintenance. The most common failure mode is attributed to so-called axial cracks or white-etching cracks, which primarily affect the intermediate and high-speed-stage bearings. The high-speed-shaft and bearing loads and sliding will be measured with a specially instrumented gearbox installed in a 1.5-megawatt turbine at the National Wind Technology Center in an upcoming test campaign. Additional instrumentation will also measure the tribological environment of these bearings, including bearing temperatures, lubricant temperature and water content, air temperature and humidity, and stray electrical current across the bearings. This paper fully describes the instrumentation package and summarizes initial results.

  2. An Advanced Microturbine System with Water-Lubricated Bearings

    Directory of Open Access Journals (Sweden)

    Susumu Nakano

    2009-01-01

    Full Text Available A prototype of the next-generation, high-performance microturbine system was developed for laboratory evaluation. Its unique feature is its utilization of water. Water is the lubricant for the bearings in this first reported application of water-lubricated bearings in gas turbines. Bearing losses and limitations under usage conditions were found from component tests done on the bearings and load tests done on the prototype microturbine. The rotor system using the water-lubricated bearings achieved stable rotating conditions at a rated rotational speed of 51,000 rpm. An electrical output of 135 kW with an efficiency of more than 33% was obtained. Water was also utilized to improve electrical output and efficiency through water atomizing inlet air cooling (WAC and a humid air turbine (HAT. The operation test results for the WAC and HAT revealed the WAC and HAT operations had significant effects on both electrical output and electrical efficiency.

  3. Food availability and foraging near human developments by black bears

    Science.gov (United States)

    Merkle, Jerod A.; Robinson, Hugh S.; Krausman, Paul R.; Alaback, Paul B.

    2013-01-01

    Understanding the relationship between foraging ecology and the presence of human-dominated landscapes is important, particularly for American black bears (Ursus americanus), which sometimes move between wildlands and urban areas to forage. The food-related factors influencing this movement have not been explored, but can be important for understanding the benefits and costs to black bear foraging behavior and the fundamental origins of bear conflicts. We tested whether the scarcity of wildland foods or the availability of urban foods can explain when black bears forage near houses, examined the extent to which male bears use urban areas in comparison to females, and identified the most important food items influencing bear movement into urban areas. We monitored 16 collared black bears in and around Missoula, Montana, during 2009 and 2010, while quantifying the rate of change in green vegetation and the availability of 5 native berry-producing species outside the urban area, the rate of change in green vegetation, and the availability of apples and garbage inside the urban area. We used parametric time-to-event models in which an event was a bear location collected within 100 m of a house. We also visited feeding sites located near houses and quantified food items bears had eaten. The probability of a bear being located near a house was 1.6 times higher for males, and increased during apple season and the urban green-up. Fruit trees accounted for most of the forage items at urban feeding sites (49%), whereas wildland foods composed Black bears foraged on human foods near houses even when wildland foods were available, suggesting that the absence of wildland foods may not influence the probability of bears foraging near houses. Additionally, other attractants, in this case fruit trees, appear to be more important than the availability of garbage in influencing when bears forage near houses.

  4. Bearing for liquid metal pump

    International Nuclear Information System (INIS)

    Dickinson, R.J.; Pennell, W.E.; Wasko, J.

    1984-01-01

    A liquid metal pump bearing support comprises a series of tangentially oriented spokes that connect the bearing cylinder to the pump internals structure. The spokes may be arranged in a plurality of planes extending from the bearing cylinder to the pump internals with the spokes in one plane being arranged alternately with those in the next plane. The bearing support structure provides the pump with sufficient lateral support for the bearing structure together with the capability of accommodating differential thermal expansion without adversely affecting pump performance

  5. Bearing, gearing, and lubrication technology

    Science.gov (United States)

    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.

  6. Experimental investigations of active air bearings

    DEFF Research Database (Denmark)

    Santos, Ilmar; Morosi, Stefano

    2012-01-01

    Along with traditional oil lubrication, increasing demand for high-speed applications has renewed attention to gas bearings technology. Traditional aerostatic and aerodynamic gas lubrication has been widely used in a variety of applications, ranging from high-speed spindles to micro and meso......-scale turbomachinery. The present paper deals with experimental rotordynamic testing of a flexible rotor supported by hybrid aerostaticaerodynamic gas journal bearing equipped with an electronic radial air injection system. From a rotordynamic point of view there are two phenomena that limit the widespread...... of traditional gas lubrication: 1) Low damping makes operation across critical speed dangerous, as even low level of unbalance can generate large vibration responses. This is especially problematic for gas bearing applications, which often operate in the supercritical region. Moreover, 2) An upper bound...

  7. Powder metallurgy bearings for advanced rocket engines

    Science.gov (United States)

    Fleck, J. N.; Killman, B. J.; Munson, H.E.

    1985-01-01

    Traditional ingot metallurgy was pushed to the limit for many demanding applications including antifriction bearings. New systems require corrosion resistance, better fatigue resistance, and higher toughness. With conventional processing, increasing the alloying level to achieve corrosion resistance results in a decrease in other properties such as toughness. Advanced powder metallurgy affords a viable solution to this problem. During powder manufacture, the individual particle solidifies very rapidly; as a consequence, the primary carbides are very small and uniformly distributed. When properly consolidated, this uniform structure is preserved while generating a fully dense product. Element tests including rolling contact fatigue, hot hardness, wear, fracture toughness, and corrosion resistance are underway on eleven candidate P/M bearing alloys and results are compared with those for wrought 440C steel, the current SSME bearing material. Several materials which offer the promise of a significant improvement in performance were identified.

  8. Integrated smart bearings for next generation aero-engines Part 1: Development of a sensor suite for automatic bearing health monitoring

    OpenAIRE

    Bashir, Imran; Wang, Ling; Harvey, Terence; Zaghari, Bahareh; Weddell, Alexander; White, Neil

    2017-01-01

    The development of smart bearing solutions will contribute to increased aircraft engine reliability, allowing the early detection of bearing failure through robust health monitoring. This project aims to develop intelligent bearing systems for an Ultra High Propulsion Efficiency (UHPE) ground test demonstrator, where a fully integrated self-powered wireless sensing system will be developed for future aircraft. This paper provides a comprehensive review of the state-of-the-art smart bearing te...

  9. Bearing construction for refrigeration compresssor

    Science.gov (United States)

    Middleton, Marc G.; Nelson, Richard T.

    1988-01-01

    A hermetic refrigeration compressor has a cylinder block and a crankshaft rotatable about a vertical axis to reciprocate a piston in a cylinder on the cylinder block. A separate bearing housing is secured to the central portion of the cylinder block and extends vertically along the crankshaft, where it carries a pair of roller bearings to journal the crankshaft. The crankshaft has a radially extending flange which is journaled by a thrust-type roller bearing above the bearing housing to absorb the vertical forces on the crankshaft so that all three of the roller bearings are between the crankshaft and the bearing housing to maintain and control the close tolerances required by such bearings.

  10. 77 FR 70423 - Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC...

    Science.gov (United States)

    2012-11-26

    ... Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of..., 2012, Black Bear Hydro Partners, LLC, sole licensee (transferor) and Black Bear Development Holdings, LLC and Black Bear SO, LLC (transferees) filed an application for the partial the transfer of licenses...

  11. Introgressive hybridization: brown bears as vectors for polar bear alleles.

    Science.gov (United States)

    Hailer, Frank

    2015-03-01

    The dynamics and consequences of introgression can inform about numerous evolutionary processes. Biologists have therefore long been interested in hybridization. One challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. In this issue of Molecular Ecology, Cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one American black bear. Polar bear alleles are found to be introgressed into brown bears not only near a previously identified admixture zone on the Alaskan Admiralty, Baranof and Chichagof (ABC) Islands, but also far into the North American mainland. Elegantly contrasting admixture levels at autosomal and X chromosomal markers, Cahill and colleagues infer that male-biased dispersal has spread these introgressed alleles away from the Late Pleistocene contact zone. Compared to a previous study on the ABC Island population in which an Alaskan brown bear served as a putatively admixture-free reference, Cahill et al. (2015) utilize a newly sequenced Swedish brown bear as admixture baseline. This approach reveals that brown bears have been impacted by introgression from polar bears to a larger extent (up to 8.8% of their genome), than previously known, including the bear that had previously served as admixture baseline. No evidence for introgression of brown bear into polar bear is found, which the authors argue could be a consequence of selection. Besides adding new exciting pieces to the puzzle of polar/brown bear evolutionary history, the study by Cahill and colleagues highlights that wildlife genomics is moving from analysing single genomes towards a landscape genomics approach. © 2015 John Wiley & Sons Ltd.

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

    Science.gov (United States)

    Ream, L. W.

    1974-01-01

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

  13. Plain bearing stresses due to forming and oil film pressure

    Energy Technology Data Exchange (ETDEWEB)

    Burke-Veliz, A; Reed, P A S; Syngellakis, S [University of Southampton, School of Engineering Sciences, Southampton SO17 1BJ (United Kingdom); Wang, D; Wahdy, N; Merritt, D, E-mail: allan.burke@itesm.m [MAHLE Engine Systems UK Ltd, 2 Central park Drive, Rugby CV23 0WE (United Kingdom)

    2009-08-01

    This paper describes a methodology for assessing critical stress ranges arising in automotive plain bearings during engine operations. An industry-produced and run simulation program provides information on oil film pressure and overall bearing deformation during accelerated performance tests. This code performs an elasto-hydrodynamic lubrication analysis accounting for the compliance of the housing and journal. Finite element analyses of a multilayer bearing are performed to assess the conditions responsible for possible fatigue damage over the bearing lining. The residual stresses arising from the forming and fitting process are first assessed. The stress analyses over the engine cycle show the intensity and distribution of cyclic tensile and compressive stresses in the bearing. The location of maximum stress range is found to be consistent with the damage observed in accelerated fatigue tests. Critical zones are identified in the lining for possible fatigue crack initiation and growth studies.

  14. A study on creep properties of laminated rubber bearings. Pt. 1. Creep properties and numerical simulations of thick rubber bearings

    International Nuclear Information System (INIS)

    Matsuda, Akihiro; Yabana, Shuichi

    2000-01-01

    In this report, to evaluate creep properties and effects of creep deformation on mechanical properties of thick rubber bearings for three-dimensional isolation system, we show results of compression creep test for rubber bearings of various rubber materials and shapes and development of numerical simulation method. Creep properties of thick rubber bearings were obtained from compression creep tests. The creep strain shows steady creep that have logarithmic relationships between strain and time and accelerated creep that have linear relationships. We make numerical model of a rubber material with nonlinear viscoelastic constitutional equations. Mechanical properties after creep loading test are simulated with enough accuracy. (author)

  15. Recent research and development of bearings for helium circulator

    International Nuclear Information System (INIS)

    Taniguchi, S.; Ezaki, Z.; Kawaguchi, K.; Matsumura, N.; Kozima, M.

    1988-01-01

    This paper mainly describes recent studies and successful applications of water lubricated bearing and gas lubricated bearing. Both types of bearing seem to be suitable for a turbo machine installed in an atomic energy plant - such as the helium circulator of a HTGR - not to be affected by radioactivity, so we have been attracted by them for about 10 years. The former was investigated theoretically taking account of turbulent flow due to the low viscosity of water, and compared with the experimental data. Good agreement was obtained, and a successful example applied to a small-sized high speed air compressor is shown. The latter was investigated using a large-sized bearing test rig simulated to an actual machine. The tilting pad journal bearing and the tilting pad thrust bearing were taken and improved for some aspects. These bearings have been taken into service on an actual circulator and are now operating successfully. Currently, a magnetic bearing is being studied to pay special attention to endurance for an earthquake and catcher bearing system. We would like to have an opportunity to present these results in the near future. (author). 5 refs, 15 figs, 2 tabs

  16. Performance of solid lubricated ball bearings at high-temperatures in a vacuum

    Science.gov (United States)

    Seki, Katsumi; Suzuki, Mineo; Nishimura, Makoto; Hasegawa, Masaji; Moriyama, Minoru

    1994-07-01

    Ball bearings which can operate at high temperatures in a vacuum will be required with advances in technology. Among the issues for the operation of ball bearings at high temperatures, solid lubricants and bearing materials are crucial. The aim of this study was to develop ball bearings for use at high temperatures in a vacuum. The tested bearings were 20-mm bore-sized angular contact ball bearings. Three combinations of bearing materials were tested: M-50 bearings, hybrid bearings with M-50 races and Si3N4 balls, and Si3N4 bearings. M-50 bearings were lubricated with a silver film. Hybrid and ceramic bearings were lubricated with a pre-coated sputtered MoS2 film and a self-lubricating hot-pressed composite retainer. Tests were carried out at temperatures up to 500 C and a rotational speed of 600 rpm under an axial load of 50 N in a vacuum. Excellent performance at 500 C in a vacuum was obtained for Si3N4 bearings. Frictional torque was low and stable for more than 5x10(exp 7) revolutions. After the tests, the bearings were in very good condition with a small amount of wear. Hybrid bearings also showed very good performance at 350 C in a vacuum. M-50 steel bearings were operated without failure at 350 C in a vacuum, although frictional torque was rather high and unstable. X-ray photoelectron spectroscopy (XPS) analysis and scanning electron microscopy (SEM) observation revealed the existence of a film on the ball surface transferred from the composite retainer for both hybrid and ceramic bearings.

  17. Telemetry experiments with a hibernating black bear

    Science.gov (United States)

    Craighead, J. J.; Varney, J. R.; Sumner, J. S.; Craighead, F. C., Jr.

    1972-01-01

    The objectives of this research were to develop and test telemetry equipment suitable for monitoring physiological parameters and activity of a hibernating bear in its den, to monitor this data and other environmental information with the Nimbus 3 IRLS data collection system, and to refine immobilizing, handling, and other techniques required in future work with wild bears under natural conditions. A temperature-telemetering transmitter was implanted in the abdominal cavity of a captive black bear and body temperature data was recorded continuously during a 3 month hibernation period. Body temperatures ranging between 37.5 and 31.8 C were observed. Body temperature and overall activity were influenced by disturbances and ambient den temperature. Nychthemeral temperature changes were not noticable. A load cell weight recording device was tested for determining weight loss during hibernation. Monitoring of data by satellite was not attempted. The implanted transmitter was removed and the bear was released with a radiolocation collar at the conclusion of the experiment.

  18. Active magnetic bearings: As applied to centrifugal pumps

    Science.gov (United States)

    Nelik, Lev; Cooper, Paul; Jones, Graham; Galecki, Dennis; Pinckney, Frank; Kirk, Gordon

    1992-01-01

    Application of magnetic bearings to boiler feed pumps presents various attractive features, such as longer bearing life, lower maintenance costs, and improved operability through control of the rotordynamics. Magnetic bearings were fitted to an eight-stage, 600 hp boiler feed pump, which generates 2600 ft of heat at 680 gpm and 3560 rpm. In addition to the varied and severe operating environment in steady state operation of this pump in a power plant, it is also subjected to transient loads during frequent starts and stops. These loads can now be measured by the in-built instrumentation of the magnetic bearings. Following site installation, a follow-up bearing tune-up was performed, and pump transient response testing was conducted. The bearing response was completely satisfactory, ensuring trouble-free pump operation even in the range of reduced load. The experience gained so far through design and testing proves feasibility of magnetic bearings for boiler feed pumps, which sets the stage for application of even higher energy centrifugal pumps equipped with magnetic bearings.

  19. Computational design of rolling bearings

    CERN Document Server

    Nguyen-Schäfer, Hung

    2016-01-01

    This book comprehensively presents the computational design of rolling bearings dealing with many interdisciplinary difficult working fields. They encompass elastohydrodynamics (EHD), Hertzian contact theory, oil-film thickness in elastohydrodynamic lubrication (EHL), bearing dynamics, tribology of surface textures, fatigue failure mechanisms, fatigue lifetimes of rolling bearings and lubricating greases, Weibull distribution, rotor balancing, and airborne noises (NVH) in the rolling bearings. Furthermore, the readers are provided with hands-on essential formulas based on the up-to-date DIN ISO norms and helpful examples for computational design of rolling bearings. The topics are intended for undergraduate and graduate students in mechanical and material engineering, research scientists, and practicing engineers who want to understand the interactions between these working fields and to know how to design the rolling bearings for automotive industry and many other industries.

  20. Stable blood lubricated hydrodynamic journal bearing with magnetic loading.

    Science.gov (United States)

    Malanoski, S B; Belawski, H; Horvath, D; Smith, W A; Golding, L R

    1998-01-01

    The Cleveland Clinic Foundation's Innovative Ventricular Assist System (IVAS) is distinguished by the use of a special hydrodynamic journal bearing to support the rotating assembly of the blood pump. In a permanently implanted blood pump, this bearing's characteristics of long life and high reliability are of paramount importance. In addition, this bearing's inherent self-pumping flow and the axial through flow caused by an imposed end-to-end pressure difference provides good washing, thus guarding against deposition. The basic computer analysis and preliminary testing results of this bearing were previously presented. This article reports the ongoing studies (both analytic and in vitro tests) on this innovative bearing as a component of the IVAS in general, with particular emphasis on its stable operating characteristics and reliability. The absence of vibration attributable to hydrodynamic instabilities related to the thick fluid film are both calculated and demonstrated during testing. A stable operating center of the rotor is shown to be inherent under magnetic side loads and resulting hydrodynamic bearing forces. A low shear as a result of large fluid-film thicknesses has been calculated, and low hemolysis has been shown by in vitro testing. Several unique design features of the bearing are believed to be responsible for this high level of performance.

  1. Grease lubrication in rolling bearings

    CERN Document Server

    Lugt, Piet M

    2012-01-01

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

  2. Improvement of bearing support lubrication

    Directory of Open Access Journals (Sweden)

    Shehovtseva E. V.

    2016-12-01

    Full Text Available Gas turbine engine bearing supports is an important part in providing product efficiency of general and special-purpose engineering industry. Attempts are being made to increase efficiency of bearing support. Such attempts are caused by the modern tendency of the development of engineering striving for compact machines and units possessing increased reliability and durability. Researches on finding discrepancies in operation of support for this purpose have been executed. The reasons of occurrence the fatigue crumbling on external bearing races at different stages development of working surface damage have been investigated. The basic constructions of support of shaft for the aviation gas turbine engine and methods of their lubrication have been considered. Shortcomings of existing methods of lubrication of bearing supports have been marked. The upgraded construction of the module of gas turbine bearing shaft, which allows to improve conditions of lubrication and bearing cooling as a result of a uniform oil feed to the contact zones of outside bearing race and rolling elements and forced oil removal from contact zones of inside bearing race and rolling elements has been suggested. The task of improving conditions of lubrication supply to an internal holder of the bearing has been solved. The developed design allows applying unconventional methods of lubrication and cooling of a bearing support. Thus it is recommended to use process of regulation of a microrough on working surfaces bearing support during grinding-in. It will allow to improve a stage grinding-in and to increase reliability and durability of bearing support.

  3. Contact Stress Design Parameters for Titanium Bearings, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Air-Lock's Phase I effort tested the effects of ball induced contact stresses on Titanium bearing races. The contact stress design limit that would achieve a...

  4. Advanced Transmission Components Investigation Program. Bearing and Seal Development.

    Science.gov (United States)

    1980-08-01

    were fabricated from consumable-electrode vacuum- melt M50 steel (AMS649) and the inner rings were made from a bar of consunable-electrode ,acuum-melt...diatmeter, hut 11one Were reCorded inl thIre O ’aIta 111 bearing. Prior to thle stat of testing, a destructive rntaC,1lngic.1 e\\arnirratrnr ol one bar ...bearings replaced the test bearings at failure and were also used to compare the life-imptovement factor to V .\\SCO-X2 steel. TESI RLSUIAS The fatigue

  5. Effects of Active Vibration Control of Journal Bearings

    Directory of Open Access Journals (Sweden)

    Jiří Tůma

    2016-09-01

    Full Text Available The article deals with the stability of the movement of the journal inside the bushing of the hydrodynamic plain bearings, which limits the operational range of rotor rotational speed. The purpose of active vibration control using piezoactuators is to increase the limit of the rotor rotation speed without onset of a whirl. It is also required maintaining the bearing journal position without vibration and reducing friction losses at the steady-state rotation. The main topic is the presentation of the results of the test of the journal bearing with the use of a test bench.

  6. Instability thresholds for flexible rotors in hydrodynamic bearings

    Science.gov (United States)

    Allaire, P. E.; Flack, R. D.

    1980-01-01

    Two types of fixed pad hydrodynamic bearings (multilobe and pressure dam) were considered. Optimum and nonoptimum geometric configurations were tested. The optimum geometric configurations were determined by using a theoretical analysis and then the bearings were constructed for a flexible rotor test rig. It was found that optimizing bearings using this technique produces a 100% or greater increase in rotor stability. It is shown that this increase in rotor stability is carried out in the absence of certain types of instability mechanisms such as aerodynamic crosscoupling. However, the increase in rotor stability should greatly improve rotating machinery performance in the presence of such forces as well.

  7. Experimental Performance Study of a High Speed Oil Lubricated Polymer Thrust Bearing

    Directory of Open Access Journals (Sweden)

    Jie Zhou

    2015-01-01

    Full Text Available With the demand for turbomachinery to operate at higher speeds, loads, and power, fluid film bearings that support turbomachinery must be capable of operating in these more demanding applications. Thrust bearings operating at high speeds and loads can experience high surface temperatures and thin fluid film thickness. Typically, babbitt (white metal is the bearing lining material for most turbomachinery bearings but is limited in operating temperature and allowable film thickness. Polymer based materials are alternative materials that can operate at high temperatures and with thin films and have been in use for many decades in high load applications, such as electric submersible pumps (ESP. Test results of polymer lined thrust bearings subjected to modern turbomachinery speeds and loads are presented and compared to babbitt lined bearings of the same design and under similar conditions. The test results show polymer lined thrust bearings can operate at higher bearing unit loads than babbitt.

  8. 49 CFR 40.385 - Who bears the burden of proof in a PIE proceeding?

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Who bears the burden of proof in a PIE proceeding... TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Public Interest Exclusions § 40.385 Who bears the burden of proof in a PIE proceeding? (a) As the proponent of issuing a PIE, the initiating official bears...

  9. Autosizing Control Panel for Needle Bearing

    OpenAIRE

    Prof.A.R.Wadhekar,; Ms Jyoti R. Rajput

    2016-01-01

    A needle roller bearing is a bearing which uses small cylindrical rollers. Bearings are used to reduce friction of any rotating surface. Needle bearings have a large surface in contact with the bearing outer surfaces as compared to ball bearings. There is less added clearance(Diameter of the shaft and the diameter of the bearing are different) so they are much compact. The structure consists of a needle cage which contains the needle rollersthemselves and an outer race (The housin...

  10. Tribological Behavior of Journal Bearing Material under Different Lubricants

    Directory of Open Access Journals (Sweden)

    S. Baskar

    2014-06-01

    Full Text Available The friction and wear behavior of journal bearing material has been investigated using pin on disc wear tester with three different lubricating oils i.e. synthetic lubricating oil (SAE20W40, chemically modified rapeseed oil (CMRO, chemically modified rapeseed oil with Nano CuO. Wear tests were carried out at maximum load of 200 N and sliding speeds of 2 – 10 m/s. The results showed that the friction and wear behavior of the journal bearing material have changed according to the sliding conditions and lubricating oils. The journal bearing material has a lower friction coefficient for CMRO with Nano CuO than other two oils. Higher wear of journal bearing material was observed in SAE 20W40 and CMRO. Worn surfaces of the journal bearing material with three lubricating oils were examined using scanning electron microscope (SEM and wear mechanisms were discussed.

  11. Operating characteristics of a cantilever-mounted resilient-pad gas-lubricated thrust bearing

    Science.gov (United States)

    Nemeth, Z. N.

    1979-01-01

    A resilient-pad gas thrust bearing consisting of pads mounted on cantilever beams was tested to determine its operating characteristic. The bearing was run at a thrust load of 74 newtons to a speed of 17000 rpm. The pad film thickness and bearing friction torque were measured and compared with theory. The measured film thickness was less than that predicted by theory. The bearing friction torque was greater than that predicted by theory.

  12. Experimental and theoretical analysis of a rigid rotor supported by air foil bearings

    DEFF Research Database (Denmark)

    Larsen, Jon Steffen; Hansen, Asger J. T.; Santos, Ilmar

    2015-01-01

    The popularity of compressors utilizing foil bearings is increasing. Their mechanical design is challenging, and an accurate prediction of the bearing coefficients is important. A mathematical model taking into account the foil structure, and the detailed geometry of a three pad foil bearing are ...... for the first order equation. Calculated bearing coefficients are compared to experimental results obtained from a dedicated test rig. Generally, good agreement is observed and minor discrepancies for the damping coefficients are discussed....

  13. Gearbox Reliability Collaborative High Speed Shaft Tapered Roller Bearing Calibration

    Energy Technology Data Exchange (ETDEWEB)

    Keller, J.; Guo, Y.; McNiff, B.

    2013-10-01

    The National Renewable Energy Laboratory (NREL) Gearbox Reliability Collaborative (GRC) is a project investigating gearbox reliability primarily through testing and modeling. Previous dynamometer testing focused upon acquiring measurements in the planetary section of the test gearbox. Prior to these tests, the strain gages installed on the planetary bearings were calibrated in a load frame.

  14. Dynamic behavior of hybrid sodium bearings. Theoretical and experimental studies

    International Nuclear Information System (INIS)

    Guidez, J.; Juignet, N.; Queval, M.

    1981-08-01

    The primary sodium pump shaft lower section of a fast breeder reactor is guided by a hydrostatic sodium bearing. This recess type bearing is supplied via orifices restrictors. Sodium is sampled at hight pressure at the diffuser outlet and is then centrifuged towards the orifices restrictors. Bearing stiffness and damping data is essential for the study of rotor dynamic behavior. Two points in particular may then be studied: - calculation of rotor instability ranges and critical speeds, - dynamic behavior of the rotor in the event of an earthquake. As regards the bearing design, the problem is to obtain the pressure fields in the liquid film. The integration of these pressure fields will then give the stiffness coefficients. The damping coefficients can then be obtained by the same calculation after slight displacement. The Reynolds equation can be used to study the liquid film (under any conditions for the turbulent and inertia effects). Then the computer code DELPAL is explained that solves the modified Reynolds equation using a finite element method. The presentation of tests conducted in 1981 on the Super-Phenix 1 full scall bearing (diameter 850 mm) in water is made. In conclusion this paper describes a method for calculating the stiffness and damping matrices of a hydrostatic bearing using the DELPAL calculation code and shows the loop of behavior tests on a bearing with sinusoidal excitation. The results, obtained by calculation and by testing, are indispensable when calculating the dynamic behavior of the shaft line

  15. Prévision de la corrosion des coussinets et corrélation avec l'essai sur moteur Petter W1 L Predicting Bearing Wear and Correlation with the Petter W1 L Engine Test

    Directory of Open Access Journals (Sweden)

    Desvard A.

    2006-11-01

    Full Text Available Parmi les essais exigés par les spécifications européennes et américaines pour huiles de moteurs, il existe un essai de résistance à la corrosion des coussinets de bielles en cuivre-plomb (tableau 1. Ces essais sont effectués sur moteurs monocylindre Petter W1 L ou Labeco CLR (tableau 2. Des résultats de corrosion obtenus sur le moteur Petter W1 L, avec des huiles de calibrage, sont donnés (tableau 4 et les courbes de corrosion en fonction du temps d'essai sont représentées figure 1. En utilisant ces mêmes huiles, un groupe de travail du GFC*, chargé de développer des méthodes d'essai laboratoire de présélection, a mis au point un test basé sur le suivi de la corrosion d'une éprouvette de plomb, en présence de cuivre, immergée dans le lubrifiant à évaluer, lorsque celui-ci est soumis à des conditions d'oxydation sévères, en présence d'air, à haute température (fig. 2. Les résultats obtenus sont en parfaite concordance avec les résultats sur moteurs (tableau 5 et fig. 3. Par ailleurs, ces essais mettent en évidence une excellente répétabilité (fig. 4,et une excellente reproductibilité (fig. 5 et 6 de la méthode de laboratoire. * GFC : Groupement Français de Coordination, pour le développement des essais de performance des combustibles, des lubrifiants pour moteurs et autres fluides utilisés dans les transports. Among the tests required by European and American specifications for motor oils, there is a test of the corrosion resistance of copper-lead bearings (Table 1. These tests are performed in single-cylinder Petter W1 L engines or Labeco CLR engines (Table 2. The corrosion results obtained with the Petter W1 L engine, for calibration oils, are given (Table 4, and the corrosion curves as a function of time are shown in Fig. 1. By using the same oils, a GFC working group responsible for developing laboratory preselection test methods has developed a test based on the determining of the corrosion of a lead

  16. Permanent-Magnet Meissner Bearing

    Science.gov (United States)

    Robertson, Glen A.

    1994-01-01

    Permanent-magnet meissner bearing features inherently stable, self-centering conical configuration. Bearing made stiffer or less stiff by selection of magnets, springs, and spring adjustments. Cylindrical permanent magnets with axial magnetization stacked coaxially on rotor with alternating polarity. Typically, rare-earth magnets used. Magnets machined and fitted together to form conical outer surface.

  17. Superconducting bearings for flywheel applications

    DEFF Research Database (Denmark)

    Abrahamsen, A.B.

    2001-01-01

    A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found onthe applications of superconducting bearings...

  18. What about the Javan Bear?

    NARCIS (Netherlands)

    Jentink, F.A.

    1898-01-01

    The other day I read in a dutch popular periodical a paper dealing with the different species of Bears and their geographical distribution. To my great surprise the Malayan Bear was mentioned from Java: the locality Java being quite new to me I wrote to the author of that paper and asked him some

  19. Biomechanical consequences of rapid evolution in the polar bear lineage.

    Directory of Open Access Journals (Sweden)

    Graham J Slater

    2010-11-01

    Full Text Available The polar bear is the only living ursid with a fully carnivorous diet. Despite a number of well-documented craniodental adaptations for a diet of seal flesh and blubber, molecular and paleontological data indicate that this morphologically distinct species evolved less than a million years ago from the omnivorous brown bear. To better understand the evolution of this dietary specialization, we used phylogenetic tests to estimate the rate of morphological specialization in polar bears. We then used finite element analysis (FEA to compare the limits of feeding performance in the polar bear skull to that of the phylogenetically and geographically close brown bear. Results indicate that extremely rapid evolution of semi-aquatic adaptations and dietary specialization in the polar bear lineage produced a cranial morphology that is weaker than that of brown bears and less suited to processing tough omnivorous or herbivorous diets. Our results suggest that continuation of current climate trends could affect polar bears by not only eliminating their primary food source, but also through competition with northward advancing, generalized brown populations for resources that they are ill-equipped to utilize.

  20. Biomechanical consequences of rapid evolution in the polar bear lineage.

    Science.gov (United States)

    Slater, Graham J; Figueirido, Borja; Louis, Leeann; Yang, Paul; Van Valkenburgh, Blaire

    2010-11-05

    The polar bear is the only living ursid with a fully carnivorous diet. Despite a number of well-documented craniodental adaptations for a diet of seal flesh and blubber, molecular and paleontological data indicate that this morphologically distinct species evolved less than a million years ago from the omnivorous brown bear. To better understand the evolution of this dietary specialization, we used phylogenetic tests to estimate the rate of morphological specialization in polar bears. We then used finite element analysis (FEA) to compare the limits of feeding performance in the polar bear skull to that of the phylogenetically and geographically close brown bear. Results indicate that extremely rapid evolution of semi-aquatic adaptations and dietary specialization in the polar bear lineage produced a cranial morphology that is weaker than that of brown bears and less suited to processing tough omnivorous or herbivorous diets. Our results suggest that continuation of current climate trends could affect polar bears by not only eliminating their primary food source, but also through competition with northward advancing, generalized brown populations for resources that they are ill-equipped to utilize.

  1. Performance of an active electric bearing for rotary micromotors

    International Nuclear Information System (INIS)

    Han, F T; Wang, L; Wu, Q P; Liu, Y F

    2011-01-01

    An electric bearing used to support a micromachined rotor of variable-capacitance motors was designed and tested in order to study the characteristics of this frictionless bearing. Electrostatic suspension of a ring-shaped rotor in five degrees of freedom is required to eliminate the mechanical bearing and thus the friction and wear between the rotor and the substrate. Bulk microfabrication-based glass/silicon/glass bonding is chosen for this device, allowing the fabrication of large area sense capacitors and rotor, which make the device potentially suitable for the development of an electrostatically suspended micromachined gyroscope. The device and its basic operating principle are described, as well as the dynamics of the rotor and basic design considerations of the electric bearing system. A theoretical relationship to relate the characteristics of a classical lag–lead compensator to the stiffness properties of the electric bearing is developed to explain the experimental bearing measurements. The experimental results of closed-loop frequency response, suspension stiffness and drive voltage effects are presented and discussed for the bearing operated initially in the atmospheric environment. The performance of a tri-axial electrostatic accelerometer has also been experimentally investigated on the prototype of the electric bearing system

  2. Lateral Response Comparison of Unbonded Elastomeric Bearings Reinforced with Carbon Fiber Mesh and Steel

    Directory of Open Access Journals (Sweden)

    Ali Karimzadeh Naghshineh

    2015-01-01

    Full Text Available The vertical and horizontal stiffness used in design of bearings have been established in the last few decades. At the meantime, applicability of the theoretical approach developed to estimate vertical stiffness of the fiber-reinforced bearings has been verified in different academic studies. The suitability of conventional horizontal stiffness equation developed for elastomeric material, mainly for steel-reinforced elastomeric bearings, has not been tested in detail for use of fiber-reinforced elastomeric bearings. In this research, lateral response of fiber mesh-reinforced elastomeric bearings has been determined through experimental tests and the results have been compared by corresponding values pertaining to the steel-reinforced bearings. Within the test program, eight pairs of fiber mesh-reinforced bearings and eight pairs of steel-reinforced bearings are subjected to different levels of compressive stress and cyclic shear strains. Fiber-reinforced elastomeric bearings may be more favorable to be used in seismic regions due to lower horizontal stiffness that can result in mitigation of seismic forces for levels of 100% shear strain. Damping properties of these types of fiber mesh-reinforced bearings depend mostly on the selection of elastomeric material compounds. Suggestions have been made for the lateral response of fiber-reinforced elastomeric bearings. It has also been determined that the classical equation for lateral stiffness based on linear elastic behavior assumptions developed for elastomeric bearings does not always apply to the fiber-reinforced ones.

  3. Nonlinear control of magnetic bearings

    Science.gov (United States)

    Pradeep, A. K.; Gurumoorthy, R.

    1994-01-01

    In this paper we present a variety of nonlinear controllers for the magnetic bearing that ensure both stability and robustness. We utilize techniques of discontinuous control to design novel control laws for the magnetic bearing. We present in particular sliding mode controllers, time optimal controllers, winding algorithm based controllers, nested switching controllers, fractional controllers, and synchronous switching controllers for the magnetic bearing. We show existence of solutions to systems governed by discontinuous control laws, and prove stability and robustness of the chosen control laws in a rigorous setting. We design sliding mode observers for the magnetic bearing and prove the convergence of the state estimates to their true values. We present simulation results of the performance of the magnetic bearing subject to the aforementioned control laws, and conclude with comments on design.

  4. Flywheel Challenge: HTS Magnetic Bearing

    International Nuclear Information System (INIS)

    Werfel, F N; Floegel-Delor, U; Riedel, T; Rothfeld, R; Wippich, D; Goebel, B

    2006-01-01

    A 200 mm cylindrical engineering prototype high temperature superconducting (HTS) was designed and fabricated. Measurements show that the 17 kg PM rotor can suspend safely 1000 kg in axial direction and 470 kg radially. The rationale for the bearing performance is to stabilize a 400 kg rotor of a new compact 5 kWh/280 kW flywheel energy storage system (COM - FESS). Measurements of the magnetic bearing force, stiffness and drag-torque are presented indicated the successful targeting a milestone in the HTS bearing technology. The influence of the PM configuration and the YBCO temperature on the bearing performance was experimentally studied, providing high-force or high-stiffness behaviour. The axial stiffness 5 kN/mm at 0.5 mm displacement is the highest value of a HTS bearing we know

  5. Compliant Foil Journal Bearing Performance at Alternate Pressures and Temperatures

    Science.gov (United States)

    Bruckner, Robert J.; Puleo, Bernadette J.

    2008-01-01

    An experimental test program has been conducted to determine the highly loaded performance of current generation gas foil bearings at alternate pressures and temperatures. Typically foil bearing performance has been reported at temperatures relevant to turbomachinery applications but only at an ambient pressure of one atmosphere. This dearth of data at alternate pressures has motivated the current test program. Two facilities were used in the test program, the ambient pressure rig and the high pressure rig. The test program utilized a 35 mm diameter by 27 mm long foil journal bearing having an uncoated Inconel X-750 top foil running against a shaft with a PS304 coated journal. Load capacity tests were conducted at 3, 6, 9, 12, 15, 18, and 21 krpm at temperatures from 25 to 500 C and at pressures from 0.1 to 2.5 atmospheres. Results show an increase in load capacity with increased ambient pressure and a reduction in load capacity with increased ambient temperature. Below one-half atmosphere of ambient pressure a dramatic loss of load capacity is experienced. Additional lightly loaded foil bearing performance in nitrogen at 25 C and up to 48 atmospheres of ambient pressure has also been reported. In the lightly loaded region of operation the power loss increases for increasing pressure at a fixed load. Knowledge of foil bearing performance at operating conditions found within potential machine applications will reduce program development risk of future foil bearing supported turbomachines.

  6. Rotordynamic and Friction Loss Measurements on a High Speed Laval Rotor Supported by Floating Ring Bearings

    Directory of Open Access Journals (Sweden)

    Rob Eling

    2017-03-01

    Full Text Available Floating ring bearings are the commonly used type of bearing for automotive turbochargers. The automotive industry continuously investigates how to reduce the bearing friction losses and how to create silent turbochargers. Many of these studies involve creating a numerical model of the rotor-bearing system and performing validation on a test bench on which a turbocharger is driven by hot gases. This approach, however, involves many uncertainties which diminish the validity of the measurement results. In this study, we present a test setup in which these uncertainties are minimized. The measurement results show the behavior of the floating ring bearing as a function of oil feed pressure, oil feed temperature, rotor unbalance and bearing clearances. Next to an increased validity, the test setup provides measurement data with good repeatability and can therefore represent a case study which can be used for validation of rotor-bearing models.

  7. Ni-Ti Next Generation Bearings for Space Applications

    Science.gov (United States)

    DellaCorte, Christopher

    2018-01-01

    NASA applications challenge traditional bearing materials. The rigors of launch often include heavy shock loads and exposure to corrosive environments (e.g., salt spray). Unfortunately, ball and roller bearings made from hardened steels are vulnerable to Brinell denting and rust which can limit performance and life. Ceramic materials can eliminate corrosion concerns but their high stiffness and extreme hardness actually makes denting problems worse. In this presentation, an emerging superelastic alloy, NiTi, is introduced for rolling element bearing applications. Through a decade of RD, NiTi alloy bearings have been put through a comprehensive series of life and performance tests. Hardness, corrosion, strength, stiffness, and rolling contact fatigue tests have been conducted and reported. Ball bearings ranging in size from 12 to 50mm bore have been successfully engineered and operated over a wide range of speeds and test conditions including being submerged in water. The combination of high hardness, moderate elastic modulus, low density, and intrinsic corrosion immunity provide new possibilities for mechanisms that operate under extreme conditions. Recent preliminary tests indicate that bearings can be made from NiTi alloys that are easily lubricated by conventional oils and greases and exhibit acceptable rolling contact fatigue resistance. This presentation introduces the NiTi materials systems and shows how NASA is using it to alleviate several specific problems encountered in advanced space applications.

  8. DESIGN HANDBOOK ON GAS BEARINGS FOR GYROSCOPES.

    Science.gov (United States)

    consisting of a plain journal for supporting radial loads flanked by two spiral-grooved thrust bearings to support double-acting thrust loads; (3) the spiral-grooved journal bearing ; and (4) the spiral-grooved conical bearing.

  9. Hybrid Hydrostatic/Transient Roller Bearing Assembly

    Science.gov (United States)

    Justak, John F.

    1992-01-01

    Proposed bearing assembly for shaft of high-speed turbopump includes both hydrostatic and rolling-element bearings. Rolling-element bearing unloaded at high speed by centrifugal expansion of outer race and transient retainer.

  10. Two pad axially grooved hydrostatic bearing

    Science.gov (United States)

    San Andres, Luis A. (Inventor)

    1995-01-01

    A hydrostatic bearing having two axial grooves on opposite sides of the bearing for breaking the rotational symmetry in the dynamic force coefficients thus reducing the whirl frequency ratio and increasing the damping and stiffness of the hydrostatic bearing.

  11. Deformation Analysis of Fixed Bearing Inclined Plane Thrust Bearing

    Directory of Open Access Journals (Sweden)

    LI Yong--hai

    2017-02-01

    Full Text Available According to the theory of lubrication,Numerical simulation of the deformation of the thrust bearing of the fixed inclined plane was carried out,by finite element numerical analysis method and using the ANSYS software. The mathematical model of the oil film shape control equations about of the deformation and bearing is established. Analytical result showed that the force caused the tile surface generating concave deformation,and convex deformation increased with the height and the size of the load and bearing;Tile surface temperature generated convex deformation and increased with the height and the size of the temperature of bearing bush;The actual deformation of the tile surface is the superposition of the force and the thermal deformation. This conclusion can provide reference for the design and the application of thrust bearing,to reduce the tile surface,which is not conducive to the carrying capacity of the concave deformation.

  12. EFFECT OF BEARING MACROGEOMETRY ON BEARING PERFORMANCE IN ELASTOHYDRODYNAMIC LUBRICATION

    Directory of Open Access Journals (Sweden)

    Emin GÜLLÜ

    2000-01-01

    Full Text Available During manufacturing, ideal dimension and mutual positioning of machine elements proposed in project desing can be achieved only within certain range of tolerances. These tolerances, being classified in two groups, related to micro and macro geometry of machine elements, don't have to effect the functioning of these elements. So, as for all machine elements, investigation of the effects of macro and micro tolerances for journal bearings is important. In this study, we have investigated the effect of macro geometric irregularities of journal bearings on performance characteristics. In this regard, we have studied the change of bearing performance in respect to deviation from ideal circle for an elliptic shaft with small ovality rolling in circular journal bearing.

  13. Bears, Big and Little. Young Discovery Library Series.

    Science.gov (United States)

    Pfeffer, Pierre

    This book is written for children 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume describes: (1) the eight species of bears, including black bear, brown bear, grizzly bear, spectacled bear, sun bear, sloth bear, polar bear, and giant panda; (2) geographical habitats of bears; (3)…

  14. Non-contacting "snubber bearing" for passive magnetic bearing systems

    Science.gov (United States)

    Post, Richard F

    2017-08-22

    A new non-contacting magnetic "snubber" bearing is provided for application to rotating systems such as vehicular electromechanical battery systems subject to frequent accelerations. The design is such that in the equilibrium position the drag force of the snubber is very small (milliwatts). However in a typical case, if the rotor is displaced by as little as 2 millimeters a large restoring force is generated without any physical contact between the stationary and rotating parts of the snubber bearing.

  15. Experimental determination of the distributed dynamic coefficients for a hydrodynamic fluid film bearing

    Science.gov (United States)

    Gyurko, John Harrison

    Most current rotor bearing analysis utilizes lumped parameter bearing coefficients to model the static and dynamic characteristics of fluid film bearings. By treating the stiffness and damping properties of the fluid film as acting upon the axial centerline of the rotor, these models are limited in their analysis to first order lateral rotor-bearing motion. The development of numerical methods that distribute the dynamic properties of the fluid film around the bearing circumference allow for higher order analysis of the motion between the bearing and rotor. Assessment of the accuracy of the numerical method used to calculate distributed dynamic fluid film bearing coefficients is performed by developing a novel hydrodynamic journal bearing test rig and experimental testing procedure capable of obtaining measured distributed dynamic coefficients over a range of bearing operating conditions. The instrumented bearing test rig is used to measure the dynamic bearing displacement and fluid film pressure responses from application of an externally applied excitation force. Least squares solution to a system of perturbated pressure equations, populated by measured displacement and pressure responses, is used to determine the hydrodynamic stiffness and damping properties for a finite region of the bearing surface. Incremental rotation of pressure sensors embedded in the body of the test bearing allow for measurement of the fluid film circumferential pressure distribution which is used to calculate a set of experimentally determined dynamic bearing coefficients. Distributed bearing coefficients derived from experimental measurements are compared to numerically calculated distributed coefficients as well as to lumped parameter coefficients generated from experimental and numerical methods found in the literature. Overall, the numerically calculated distributed coefficients successfully model both the circumferential distribution and the operating conditions of the experimental

  16. Design of A Center Deviation Adaptive Bearing Pressure Assembly Machine

    OpenAIRE

    Zhibin Chang; Lei Zhang; Guangguo Zhang

    2012-01-01

    A car transmission in order to solve the production of eight gear and nine file two models of the transmission of tapered roller bearing outer ring manual assembly accuracy, low noise, the efficiency is low, the labor intensity and difficult to realize automatic assembly line requirements so assembly problem, put forward the center deviation adaptive bearing pressure assembly machine development. Through the research, design, test and making, eventually developed used in automobile gearbox be...

  17. Thin Dense Chrome Bearing Insertion Program

    National Research Council Canada - National Science Library

    Rhoads, Mark

    1997-01-01

    .... TDC coated bearings demonstrated improved corrosion and contamination resistance. TDC coated bearings also demonstrated acceptable performance during thermal cycle, oil-off, and induced defect conditions...

  18. Development of long-life, low-noise linear bearings for atmospheric interferometry

    Science.gov (United States)

    Roberts, E. W.; Watters, R. B.; Gill, S.; Birner, R.; Lange, G.; Posselt, W.

    1994-05-01

    This paper describes the development of dry-lubricated linear bearings for use on the Michelson interferometer for passive atmospheric sounding (MIPAS). Two candidate bearing systems were developed and tested. In the first, use was made of linear roller (needle) bearings equipped with a pulley-and-cable arrangement to prevent cage drift and to minimize roller slip. The second design was of a roller-guided bearing system in which guidance was provided by all bearings rolling along guide rods. The paper focuses on the development of these linear bearings systems and describes the approach taken in terms of bearing design, lubrication methods, screening programs, and thermal-vacuum testing. Development difficulties are highlighted and the solutions ultimately adopted are described.

  19. Design, Fabrication, and Performance of Foil Gas Thrust Bearings for Microturbomachinery Applications

    Science.gov (United States)

    Dykas, Brian; Bruckner, Robert; DellaCorte, Christopher; Edmonds, Brian; Prahl, Joseph

    2008-01-01

    A methodology for the design and construction of simple foil thrust bearings intended for parametric performance testing and low marginal costs is presented. Features drawn from a review of the open literature are discussed as they relate to bearing performance. The design of fixtures and tooling required to fabricate foil thrust bearings is presented, using conventional machining processes where possible. A prototype bearing with dimensions drawn from the literature is constructed, with all fabrication steps described. A load-deflection curve for the bearing is presented to illustrate structural stiffness characteristics. Start-top cycles are performed on the bearing at a temperature of 425 C to demonstrate early-life wear patterns. A test of bearing load capacity demonstrates useful performance when compared with data obtained from the open literature.

  20. Study on the Stiffness Correction Method of Novel Antivibration Bearing for Urban Rail Transit Viaduct

    Directory of Open Access Journals (Sweden)

    Weiping Xie

    2017-01-01

    Full Text Available A novel antivibration bearing is developed to reduce the train-induced vibrations for urban rail transit viaduct. It adopts four high-damping thick rubber blocks stacking slantingly to reduce the vibration and provide large lateral stiffness. But the existing stiffness calculation method of laminated rubber bearing aimed at horizontal seismic isolation is unsuitable for thick rubber bearing designed for vertical vibration reduction. First, the stiffness correction method has been proposed based on the characteristics of the novel bearing. Second, to validate the design method, mechanical property tests are performed on a specimen of the novel bearing with design frequency at 8 Hz and with 3500 kN bearing capacity. Third, damping effects of the novel bearing are investigated through impulse vibration tests on scaled models. Results show that the mechanical property of the novel bearing can satisfy the engineering demand, and the proposed method for calculating the stiffness agrees well with the test results. The overall insertion loss of the novel bearing is 13.49 dB which is 5.32 dB larger than that of steel bearing, showing that the novel bearing is very promising to be used in the field to mitigate train-induced vibrations.

  1. Improvement of hemocompatibility for hydrodynamic levitation centrifugal pump by optimizing step bearings.

    Science.gov (United States)

    Kosaka, Ryo; Yada, Toru; Nishida, Masahiro; Maruyama, Osamu; Yamane, Takashi

    2011-01-01

    We have developed a hydrodynamic levitation centrifugal blood pump with a semi-open impeller for a mechanically circulatory assist. The impeller levitated with original hydrodynamic bearings without any complicated control and sensors. However, narrow bearing gap has the potential for causing hemolysis. The purpose of the study is to investigate the geometric configuration of the hydrodynamic step bearing to minimize hemolysis by expansion of the bearing gap. Firstly, we performed the numerical analysis of the step bearing based on Reynolds equation, and measured the actual hydrodynamic force of the step bearing. Secondly, the bearing gap measurement test and the hemolysis test were performed to the blood pumps, whose step length were 0 %, 33 % and 67 % of the vane length respectively. As a result, in the numerical analysis, the hydrodynamic force was the largest, when the step bearing was around 70 %. In the actual evaluation tests, the blood pump having step 67 % obtained the maximum bearing gap, and was able to improve the hemolysis, compared to those having step 0% and 33%. We confirmed that the numerical analysis of the step bearing worked effectively, and the blood pump having step 67 % was suitable configuration to minimize hemolysis, because it realized the largest bearing gap.

  2. Experimental Study on the Dynamic Performance of Water-Lubricated Rubber Bearings with Local Contact

    Directory of Open Access Journals (Sweden)

    Wu Ouyang

    2018-01-01

    Full Text Available Accurate dynamic characteristic coefficients of water-lubricated rubber bearings are necessary to research vibration of ship propulsion system. Due to mixed lubrication state of water-lubricated rubber bearings, normal test rig and identification method are not applicable. This paper establishes a test rig to simulate shaft misalignment and proposes an identification method for water-lubricated rubber bearings, which utilizes rotor unbalanced motion to produce self-excited force rather than artificial excitation. Dynamic performance tests under different conditions are operated. The results show that when rotational speed is less than 700 r/min, even if specific pressure is 0.05 MPa, it is difficult to form complete water film for the rubber bearing which was investigated, and contact friction and collision of the shaft and bearing are frequent. In the mixed lubrication, water film, rubber, and contact jointly determine dynamic characteristics of water-lubricated rubber bearings. The contact condition has a significant effect on the bearing stiffness, and water film friction damping has a significant effect on bearing damping. As for the particular investigated bearing, when rotational speed is in the range of 400~700 r/min and specific pressure is in the range of 0.03~0.07 MPa, bearing stiffness is in the range of 5.6~10.06 N/μm and bearing damping is in the range of 1.25~2.02 Ns/μm.

  3. An Oil-Free Thrust Foil Bearing Facility Design, Calibration, and Operation

    Science.gov (United States)

    Bauman, Steve

    2005-01-01

    New testing capabilities are needed in order to foster thrust foil air bearing technology development and aid its transition into future Oil-Free gas turbines. This paper describes a new test apparatus capable of testing thrust foil air bearings up to 100 mm in diameter at speeds to 80,000 rpm and temperatures to 650 C (1200 F). Measured parameters include bearing torque, load capacity, and bearing temperatures. This data will be used for design performance evaluations and for validation of foil bearing models. Preliminary test results demonstrate that the rig is capable of testing thrust foil air bearings under a wide range of conditions which are anticipated in future Oil-Free gas turbines. Torque as a function of speed and temperature corroborates results expected from rudimentary performance models. A number of bearings were intentionally failed with no resultant damage whatsoever to the test rig. Several test conditions (specific speeds and loads) revealed undesirable axial shaft vibrations which have been attributed to the magnetic bearing control system and are under study. Based upon these preliminary results, this test rig will be a valuable tool for thrust foil bearing research, parametric studies and technology development.

  4. Mixed-mu superconducting bearings

    Science.gov (United States)

    Hull, John R.; Mulcahy, Thomas M.

    1998-01-01

    A mixed-mu superconducting bearing including a ferrite structure disposed for rotation adjacent a stationary superconductor material structure and a stationary permanent magnet structure. The ferrite structure is levitated by said stationary permanent magnet structure.

  5. Simplified installation of thrust bearings

    Science.gov (United States)

    Sensenbaugh, N. D.

    1980-01-01

    Special handling sleeve, key to method of installing thrust bearings, was developed for assembling bearings on shaft of low-pressure oxygen turbo-pump. Method eliminates cooling and vacuum-drying steps which saves time, while also eliminating possibility of corrosion formation. Procedure saves energy because it requires no liquid nitrogen for cooling shaft and no natural gas or electric power for operating vacuum oven.

  6. Lateral dampers for thrust bearings

    Science.gov (United States)

    Hibner, D. H.; Szafir, D. R.

    1985-01-01

    The development of lateral damping schemes for thrust bearings was examined, ranking their applicability to various engine classes, selecting the best concept for each engine class and performing an in-depth evaluation. Five major engine classes were considered: large transport, military, small general aviation, turboshaft, and non-manrated. Damper concepts developed for evaluation were: curved beam, constrained and unconstrained elastomer, hybrid boost bearing, hydraulic thrust piston, conical squeeze film, and rolling element thrust face.

  7. Force and stiffness characteristics of superconducting bearing prototype

    International Nuclear Information System (INIS)

    Matveev, V.; Nizhelskiy, N.; Poluschenko, O.

    2004-01-01

    The radial-axial superconducting bearing prototype was designed, fabricated and tested. The YBaCuO high-temperature superconducting (HTS) monodomain disks diameter 28 mm and thickness of h = 4; 6; 8; 10 mm, capable to trap magnetic field 1 T, were fabricated to be employed in bearing prototype. Force interaction of single field cooled HTS disks with NdFeB magnets depending on disk thickness under 1 mm magnet air gap was studied. It was found that the increase in disk thickness results in reducing radial stiffness and in growing axial one. The results obtained were used for optimization of HTS-PM arrangement, and for developing the bearing design. The designed bearing incorporates a rotor with 7 HTS disks of 4 mm thickness, total mass 90 g, and stator with two pairs of permanent annular magnets of NdFeB. It is established that the force-displacement dependencies of the bearing have three zones: non-hysteresis (elastic) zone with high stiffness up to 560 N/mm; zone of elastic interaction with stiffness 190 N/mm; hysteretic zone with stiffness 150 N/mm in which a rotor residual displacement being observed after unloading. The outer bearing diameter is 130 mm, thickness 30 mm, and mass 1.8 kg. The maximal radial load capacity of the bearing is 190 N at the rotor displacement of 1.3 mm, and the maximal axial load capacity is 85 N at the displacement of 1 mm

  8. Radial magnetic bearings: An overview

    Directory of Open Access Journals (Sweden)

    Weiyu Zhang

    Full Text Available Radial magnetic bearings (RMBs are one of the most commonly used magnetic bearings. They are used widely in the field of ultra-high speed and ultra-precise numerical control machine tools, bearingless motors, high speed flywheels, artificial heart pumps, and molecular pumps, and they are being strengthened and extended in various important areas. In this paper, a comprehensive overview is given of different bearing topologies of RMBs with different stator poles that differ in their construction, the driving mode of electromagnets, power consumption, cost, magnetic circuits, and symmetry. RMBs with different poles and couplings between the two bearing axes in the radial direction responsible for cross-coupling generation are compared. In addition, different shaped rotors are compared, as the performances of magnetic bearing-rotor systems are of great concern to rotor constructions. Furthermore, the parameter design methods, the mathematical models and control strategies of the RMBs are described in detail. From the comparison of topologies, models and control methods for RMBs, the advantages, disadvantages and utilizable perspectives are also analyzed. Moreover, several possible development trends of the RMBs are discussed. Keywords: Radial magnetic bearings (RMBs, Topologies, Mathematical mode, Control strategies, Development trends

  9. Fatigue Life Prediction in Journal Bearing

    Directory of Open Access Journals (Sweden)

    Irsyadi Yani

    2017-03-01

    Full Text Available Failure of fatigue is damaged materials where caused frequent load. Fatigue owing to some factors, which is Stress concentration on fatigue, Stress life, Effect size and surface, and Change properties of surface. The fatigue failure of a material is dependent on the interaction of a large stress with a critical flow. In essence, fatigue is controlled by the weakest link of the material, with the probability of a weak link increasing with material volume. This phenomenon is evident in the fatigue test results of a material using specimens of varying diameters. From this research we can get effect of concentration stress on strength fatigue with S-N method. On this method only count fatigue life or endurance limit from Journal bearing housing. By Finite Element Analysis, it is not so easy to determine fatigue life. When we find the first yield point, it means this point is in the highest stress state. Then we can refer S-N curve. In this paper, the effect of bearing and housing elasticity on the stress field, which could result in surface fatigue in journal bearing, has been investigated. This condition is proved with occurred slip lines on surface of specimen. These slip lines are caused on some thousands stress cycles. Additional crack is happened immediately and finally long enough crack. So that formed unstable crack that caused fracture of brittleness or fracture of toughness because section of specimen cannot keep

  10. 36 CFR 13.1236 - Bear orientation.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bear orientation. 13.1236... Developed Area § 13.1236 Bear orientation. All persons visiting the BCDA must receive an NPS-approved Bear Orientation. Failure to receive an NPS-approved Bear Orientation is prohibited. ...

  11. 49 CFR 229.69 - Side bearings.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Side bearings. 229.69 Section 229.69....69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not have more than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run in...

  12. Heuristic Explanation of Journal Bearing Instability

    Science.gov (United States)

    1982-05-01

    A fluid-filled journal bearing is viewed as a powerful pump circulating fluid around the annular space between the journal and the bearing. A small...other simple explanations of journal - bearing instability. It is shown that for non-cavitating long bearings the hypothesis predicts instability onset

  13. EVALUATION OF A LOW FRICTION - HIGH EFFICIENCY ROLLER BEARING ENGINE

    Energy Technology Data Exchange (ETDEWEB)

    Kolarik, Robert V. II; Shattuck, Charles W.; Copper, Anthony P.

    2009-06-30

    This Low Friction (High Efficiency Roller Bearing) Engine (LFE) report presents the work done by The Timken Company to conduct a technology demonstration of the benefits of replacing hydrodynamic bearings with roller bearings in the crankshaft and camshaft assemblies of an internal combustion engine for the purpose of collecting data sufficient to prove merit. The engines in the present study have been more extensively converted to roller bearings than any previous studies (40 needle roller bearings per engine) to gain understanding of the full potential of application of bearing technology. The project plan called for comparative testing of a production vehicle which was already respected for having demonstrated low engine friction levels with a rollerized version of that engine. Testing was to include industry standard tests for friction, emissions and fuel efficiency conducted on instrumented dynamometers. Additional tests for fuel efficiency, cold start resistance and other measures of performance were to be made in the actual vehicle. Comparative measurements of noise, vibration and harshness (NVH), were planned, although any work to mitigate the suspected higher NVH level in the rollerized engine was beyond the scope of this project. Timken selected the Toyota Avalon with a 3.5L V-6 engine as the test vehicle. In an attempt to minimize cost and fabrication time, a ‘made-from’ approach was proposed in which as many parts as possible would be used or modified from production parts to create the rollerized engine. Timken commissioned its test partner, FEV Engine Technology, to do a feasibility study in which they confirmed that using such an approach was possible to meet the required dimensional restrictions and tolerances. In designing the roller bearing systems for the crank and cam trains, Timken utilized as many production engine parts as possible. The crankshafts were produced from production line forgings, which use Timken steel, modified with special

  14. Eccentric exercise training as a countermeasure to non-weight-bearing soleus muscle atrophy

    Science.gov (United States)

    Kirby, Christopher R.; Ryan, Mirelle J.; Booth, Frank W.

    1992-01-01

    This investigation tested whether eccentric resistance training could prevent soleus muscle atrophy during non-weight bearing. Adult female rats were randomly assigned to either weight bearing +/- intramuscular electrodes or non-weight bearing +/- intramuscular electrodes groups. Electrically stimulated maximal eccentric contractions were performed on anesthetized animals at 48-h intervals during the 10-day experiment. Non-weight bearing significantly reduced soleus muscle wet weight (28-31 percent) and noncollagenous protein content (30-31 percent) compared with controls. Eccentric exercise training during non-weight bearing attenuated but did not prevent the loss of soleus muscle wet weight and noncollagenous protein by 77 and 44 percent, respectively. The potential of eccentric exercise training as an effective and highly efficient counter-measure to non-weight-bearing atrophy is demonstrated in the 44 percent attenuation of soleus muscle noncollagenous protein loss by eccentric exercise during only 0.035 percent of the total non-weight-bearing time period.

  15. Design, Fabrication and Performance of Open Source Generation I and II Compliant Hydrodynamic Gas Foil Bearings

    Science.gov (United States)

    DellaCorte, Christopher; Radil, Kevin C.; Bruckner, Robert J.; Howard, S. Adam

    2007-01-01

    Foil gas bearings are self-acting hydrodynamic bearings made from sheet metal foils comprised of at least two layers. The innermost top foil layer traps a gas pressure film that supports a load while a layer or layers underneath provide an elastic foundation. Foil bearings are used in many lightly loaded, high-speed turbo-machines such as compressors used for aircraft pressurization, and small micro-turbines. Foil gas bearings provide a means to eliminate the oil system leading to reduced weight and enhanced temperature capability. The general lack of familiarity of the foil bearing design and manufacturing process has hindered their widespread dissemination. This paper reviews the publicly available literature to demonstrate the design, fabrication and performance testing of both first and second generation bump style foil bearings. It is anticipated that this paper may serve as an effective starting point for new development activities employing foil bearing technology.

  16. Design, fabrication, and performance of foil journal bearing for the brayton rotating unit

    Science.gov (United States)

    Licht, L.; Branger, M.

    1973-01-01

    Foil bearings were designed and manufactured to replace pivoted-shoe journal bearings in an existing Brayton Cycle turbo-alternator-compressor. The design of this unconventional rotor support was accomplished within the constraints and space limitations imposed by the present machine, and the substitution of foil bearings was effected without changes or modification other machine components. A housing and a test rig were constructed to incorporate the new foil-bearing support into a unified assemble with an air-driven rotor and the gimbal-mounted thrust bearing, seals, and shrouds of an actual Brayton Rotating Unit. The foil bearing required no external pressure source, and stable self-acting rotation was achieved at all speeds up to 43,200 rpm. Excellent wipe-wear characteristics of the foil bearing permitted well over 1000 start-stop cycles with no deterioriation of performance in the entire speed range.

  17. Experimental validation of a bearing wear model using the directional response of the rotor-bearing system

    Directory of Open Access Journals (Sweden)

    Tiago Henrique Machado

    Full Text Available ABSTRACT The present work gives continuity in the analysis of the wear influence on cylindrical hydrodynamic bearings by presenting an experimental validation of the wear model previously proposed by the authors. This validation is carried on using the frequency response of the rotor-bearings system in directional coordinates. For this purpose, a test rig was assembled in order to evaluate the behavior of the rotating system when supported by hydrodynamic bearings with different wear patterns. The experimental measurements are used to validate the wear model, comparing the anisotropy influence on the experimental and numerical responses. The simulated directional frequency responses showed a good agreement with the experimental ones, demonstrating the potential of the proposed wear model in satisfactorily represent its influence on the rotor-bearings system response in the frequency range where the numerical model was validated.

  18. Experimental validation of a bearing wear model using the directional response of the rotor-bearing system.

    Science.gov (United States)

    Machado, Tiago Henrique; Cavalca, Katia L

    2016-01-01

    The present work gives continuity in the analysis of the wear influence on cylindrical hydrodynamic bearings by presenting an experimental validation of the wear model previously proposed by the authors. This validation is carried on using the frequency response of the rotor-bearings system in directional coordinates. For this purpose, a test rig was assembled in order to evaluate the behavior of the rotating system when supported by hydrodynamic bearings with different wear patterns. The experimental measurements are used to validate the wear model, comparing the anisotropy influence on the experimental and numerical responses. The simulated directional frequency responses showed a good agreement with the experimental ones, demonstrating the potential of the proposed wear model in satisfactorily represent its influence on the rotor-bearings system response in the frequency range where the numerical model was validated.

  19. Performance of Simple Gas Foil Thrust Bearings in Air

    Science.gov (United States)

    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

  20. Lubrication of sliding bearings for hydropower applications

    OpenAIRE

    McCarthy, Donald

    2005-01-01

    The term "sliding bearing" refers to types of bearing where two conformal surfaces (usually the stationary bearing and a moving shaft) slide relative to one another with load distributed directly across the interface. A suitable lubricant may be employed to reduce the friction between these two surfaces. In "fluid film" bearings, this lubricant builds up a layer of sufficient thickness such that the two surfaces are completely separated. Examples include journal and thrust bearings and shaft ...

  1. Lateral load performance of SIP walls with full bearing

    Science.gov (United States)

    Boren Yeh; Tom Skaggs; Xiping Wang; Tom Williamson

    2018-01-01

    The purpose of this study was to develop test data needed to characterize lateral load performance of structural insulated panel (SIP) walls with full bearing (restrained). The research program involved structural testing of 29 full-size SIP walls (8 ft tall by 8 ft long) of various configurations that bracket a range of SIP wall configurations commonly used in the...

  2. Analysis of grease contamination influence on the internal radial clearance of ball bearings by thermographic inspection

    Directory of Open Access Journals (Sweden)

    Mišković Žarko Z.

    2016-01-01

    Full Text Available One of the most important factors influencing ball bearings service life is its internal radial clearance. However, this parameter is also very complex because it depends on applied radial load and ball bearings dimensions, surface finish and manufacturing materials. Thermal condition of ball bearings also significantly affects internal radial clearance. Despite many researches performed in order to find out relevant facts about different aspects of ball bearings thermal behaviour, only few of them are dealing with the real working conditions, where high concentration of solid contaminant particles is present. That’s why the main goal of research presented in this paper was to establish statistically significant correlation between ball bearings temperatures, their working time and concentration of contaminant particles in their grease. Because of especially difficult working conditions, the typical conveyor idlers bearings were selected as representative test samples and appropriate solid particles from open pit coal mines were used as artificial contaminants. Applied experimental methodology included thermographic inspection, as well as usage of custom designed test rig for ball bearings service life testing. Finally, by obtained experimental data processing in advanced software, statistically significant mathematical correlation between mentioned bearings characteristics was determined and applied in commonly used internal radial clearance equation. That is the most important contribution of performed research - the new equation and methodology for ball bearings internal clearance determination which could be used for eventual improvement of existing bearings service life equations. [Projekat Ministarstva nauke Republike Srbije, br. TR35029 i br. TR14033

  3. The Weight-Bearing Shoulder.

    Science.gov (United States)

    Patel, Ronak M; Gelber, Jonathan D; Schickendantz, Mark S

    2018-01-01

    The shoulder achieves a wide spectrum of motion, and in a subset of patients, including those who use manual wheelchairs and upper extremity walking aids, the shoulder also serves as the primary weight-bearing joint. Because the weight-bearing shoulder is subject to considerable joint reaction forces and overuse, a broad spectrum of pathology can affect the joint. The combination of muscle imbalance and repetitive trauma presents most commonly as subacromial impingement syndrome but can progress to other pathology. Patients with high-level spinal cord injury, leading to quadriplegia and motor deficits, have an increased incidence of shoulder pain. Understanding the needs of patients who use manual wheelchairs or walking aids can help the physician to better comprehend the pathology of and better manage the weight-bearing shoulder.

  4. A parameter identification method for the rotordynamic coefficients of a high Reynolds number hydrostatic bearing

    Science.gov (United States)

    Rouvas, C.; Childs, D. W.

    1993-01-01

    In identifying the rotordynamic coefficients of a high-Reynolds-number hydrostatic bearing, fluid-flow induced forces present a unique problem, in that they provide an unmeasureable and uncontrollable excitation to the bearing. An analysis method is developed that effectively eliminates the effects of fluid-flow induced excitation on the estimation of the bearing rotordynamic coefficients, by using power spectral densities. In addition to the theoretical development, the method is verified experimentally by single-frequency testing, and repeatability tests. Results obtained for a bearing are the twelve rotordynamic coefficients (stiffness, damping, and inertia coefficients) as functions of eccentricity ratio, speed, and supply pressure.

  5. Test

    DEFF Research Database (Denmark)

    Bendixen, Carsten

    2014-01-01

    Bidrag med en kortfattet, introducerende, perspektiverende og begrebsafklarende fremstilling af begrebet test i det pædagogiske univers.......Bidrag med en kortfattet, introducerende, perspektiverende og begrebsafklarende fremstilling af begrebet test i det pædagogiske univers....

  6. Optimal design of the hydrodynamic multi-arc bearing in a centrifugal blood pump for the improvement of bearing stiffness and hemolysis level.

    Science.gov (United States)

    Yasui, Kazuya; Kosaka, Ryo; Nishida, Masahiro; Maruyama, Osamu; Kawaguchi, Yasuo; Yamane, Takashi

    2013-09-01

    The purpose of the present study is to establish an optimal design of the multi-arc hydrodynamic bearing in a centrifugal blood pump for the improvement of bearing stiffness and hemolysis level. The multi-arc bearing was designed to fulfill the required specifications: (i) ensuring the uniform bearing stiffness for various bearing angles; (ii) ensuring a higher bearing stiffness than the centrifugal force to prevent impeller whirl; and (iii) adjusting the bearing clearance as much as possible to reduce hemolysis. First, a numerical analysis was performed to optimize three design parameters of the multi-arc bearing: number of arcs N, bearing clearance C, and groove depth H. To validate the accuracy of the numerical analysis, the impeller trajectories for six pump models were measured. Finally, an in vitro hemolysis test was conducted to evaluate the hemolytic property of the multi-arc bearing. As a result of the numerical analysis, the optimal parameter combination was determined as follows: N=4, C=100 μm, and H ≥ 100 μm. In the measurements of the impeller trajectory, the optimal parameter combination was found to be as follows: N=4, C=90 μm, and H=100 μm. This result demonstrated the high reliability of the numerical analysis. In the hemolysis test, the parameter combination that achieved the smallest hemolysis was obtained as follows: N=4, C=90 μm, and H=100 μm. In conclusion, the multi-arc bearing could be optimized for the improvement of bearing stiffness and hemolysis level. © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

  7. Polar bear Ursus maritimus hearing measured with auditory evoked potentials.

    Science.gov (United States)

    Nachtigall, Paul E; Supin, Alexander Y; Amundin, Mats; Röken, Bengt; Møller, Thorsten; Mooney, T Aran; Taylor, Kristen A; Yuen, Michelle

    2007-04-01

    While there has been recent concern about the effects of sound on marine mammals, including polar bears, there are no data available measuring the hearing of any bear. The in-air hearing of three polar bears was measured using evoked auditory potentials obtained while tone pips were played to three individually anaesthetized bears at the Kolmården Djurpark. Hearing was tested in half-octave steps from 1 to 22.5 kHz. Measurements were not obtainable at 1 kHz and best sensitivity was found in the range from 11.2-22.5 kHz. Considering the tone pips were short and background noise measurements were available, absolute measurements were estimated based on an assumed mammalian integration time of 300 ms. These data show sensitive hearing in the polar bear over a wide frequency range and should cause those concerned with the introduction of anthropogenic noise into the polar bear's environment to operate with caution.

  8. Method to increase ultimate bearing capacity of skirted circular footing

    Science.gov (United States)

    Renaningsih, Satria, Isvan Fajar; Susanto, Agus; Listyawan, Anto Budi

    2017-06-01

    Bearing capacity is the most important factor in designing foundation. It is necessary to find a method to improve the bearing capacity. Skirts that are attached on the below of footing can be used as an alternative of the improvement. The method is implemented to improve the bearing capacity of shallow footing on sand soil. The aim of this study was to find the effect of additional skirt on the circular footing towards the bearing capacity of soil and towards the settlement. This study performed twelve laboratory experiments on steel circular footing with various diameters and skirt lengths. In addition, the type of soil used in this study was sand soil in which the formation of water content and compaction method was maintained. The laboratory tests indicated that skirts are very effective to improve the ultimate bearing capacity, as they can increase the length hence the ultimate bearing capacity can be enhanced by 4.70 times in certain study condition. Skirts are also capable to reduce the settlement. In general, the analysis on the same value of load of 2.00 kN indicated the decrease of the settlement is in accordance with the increase of the skirt length attached on the circular footing.

  9. Vitamin Bc -Bearing Hydrophilic Photosensitizer Conjugate for Photodynamic Cancer Theranostics.

    Science.gov (United States)

    Kim, Jiyoung; Kim, Kyoung Sub; Park, Sin-jung; Na, Kun

    2015-08-01

    The accurate diagnosis and proper therapy for cancer are essential to improve the success rate of cancer treatment. Here, we demonstrated that the vitamin Bc -bearing hydrophilic photosensitizer conjugate folic acid-polyethylene glycol-pheophorbideA (FA-PEG-PheoA) has been synthesized for the intracellular diagnosis and photodynamic therapy of a tumor. The synthesized vitamin Bc -bearing hydrophilic photosensitizer conjugate has been characterized for the folic acid receptor expressing the ability to target tumor cells, which is facilitated by the chemical conjugation with folic acid. The vitamin Bc -bearing hydrophilic photosensitizer conjugate internalization mechanism was identified through a competitive inhibition test with free folic acid. We optimized the laser-sensitive, cytotoxicity changeable, vitamin Bc -bearing hydrophilic photosensitizer conjugate concentration, which is non-cytotoxic under normal conditions and specifically cytotoxic toward cancer cells (maximum 69.15%) under laser irradiation conditions used for theranostic agents. The cancer therapeutic and diagnosis effects of synthesized conjugate were confirmed in MDA-MB-231 cells and MDA-MB-231-bearing mice. As a result, the vitamin Bc -bearing hydrophilic photosensitizer conjugate exhibited a highly photodynamic therapeutic effect, which enabled the selective detection of a folic acid receptor expressing cancer using optical imaging. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Bearing Strengths of Some Wrought-aluminum Alloys

    Science.gov (United States)

    Moore, R L; Wescoat, C

    1943-01-01

    Although a number of investigations of the bearing strength of aluminum alloys have been made, the problem remains one of considerable interest to the aircraft industry. For this reason it has seemed advisable to make additional tests of the commonly used aircraft alloys in an effort to establish a better basis for the selection of allowable bearing values. Current design practice does not recognize the effect of edge distance upon bearing strengths, and for this reason edge distance was one of the principal variables considered in this investigation. The increasing emphasis being placed upon permanent set limitations makes it essential that more information on bearing yield phenomena be obtained. The object of this investigation was to determine bearing yield and ultimate strengths of the following aluminum alloy products: 17S-T, 24S-T, Alclad 24S-T, 24S-RT, 52S-0, 52S-1/2H, 52S-H, 53S-T, and 61S-T extrusions. Ratios of these bearing properties to tensile properties were also determined.

  11. Microstructural and Material Quality Effects on Rolling Contact Fatigue of Highly Elastic Intermetallic Ball Bearings

    Science.gov (United States)

    DellaCorte, Christopher; Howard, S. Adam; Thomas, Fransua; Stanford, Malcolm K.

    2016-01-01

    Rolling element bearings made from highly-elastic intermetallic materials (HIM)s, such as 60NiTi, are under development for applications that require superior corrosion and shock resistance. Compared to steel, intermetallics have been shown to have much lower rolling contact fatigue (RCF) stress capability in simplified 3-ball on rod (ASTM STP 771) fatigue tests. In the 3-ball tests, poor material quality and microstructural flaws negatively affect fatigue life but such relationships have not been established for full-scale 60NiTi bearings. In this paper, 3-ball-on-rod fatigue behavior of two quality grades of 60NiTi are compared to the fatigue life of full-scale 50mm bore ball bearings made from the same materials. 60NiTi RCF rods with material or microstructural flaws suffered from infant mortality failures at all tested stress levels while high quality 60NiTi rods exhibited no failures at lower stress levels. Similarly, tests of full-scale bearings made from flawed materials exhibited early surface fatigue and through crack type failures while bearings made from high quality material did not fail even in long-term tests. Though the full-scale bearing test data is yet preliminary, the results suggest that the simplified RCF test is a good qualitative predictor of bearing performance. These results provide guidance for materials development and to establish minimum quality levels required for successful bearing operation and life.

  12. Seismic base isolation: Elastomer characterization, bearing modeling and system response

    International Nuclear Information System (INIS)

    Kulak, R.F.; Wang, C.Y.; Hughes, T.H.

    1991-01-01

    This paper discusses several major aspects of seismic base isolation systems that employ laminated elastomer bearings. Elastomer constitutive models currently being used to represent the nonlinear elastic and hysteretic behavior are discussed. Some aspects of mechanical characterization testing of elastomers is presented along with representative tests results. The development of a finite element based mesh generator for laminated elastomer bearings is presented. Recent advances in the simulation of base isolated structures to earthquake motions are presented along with a sample problem. 13 refs., 19 figs., 1 tab

  13. Seismic base isolation: Elastomer characterization, bearing modeling and system response

    Energy Technology Data Exchange (ETDEWEB)

    Kulak, R.F.; Wang, C.Y.; Hughes, T.H.

    1991-01-01

    This paper discusses several major aspects of seismic base isolation systems that employ laminated elastomer bearings. Elastomer constitutive models currently being used to represent the nonlinear elastic and hysteretic behavior are discussed. Some aspects of mechanical characterization testing of elastomers is presented along with representative tests results. The development of a finite element based mesh generator for laminated elastomer bearings is presented. Recent advances in the simulation of base isolated structures to earthquake motions are presented along with a sample problem. 13 refs., 19 figs., 1 tab.

  14. Wave Journal Bearing. Part 1: Analysis

    Science.gov (United States)

    Dimofte, Florin

    1995-01-01

    A wave journal bearing concept features a waved inner bearing diameter of the non-rotating bearing side and it is an alternative to the plain journal bearing. The wave journal bearing has a significantly increased load capacity in comparison to the plain journal bearing operating at the same eccentricity. It also offers greater stability than the plain circular bearing under all operating conditions. The wave bearing's design is relatively simple and allows the shaft to rotate in either direction. Three wave bearings are sensitive to the direction of an applied stationary side load. Increasing the number of waves reduces the wave bearing's sensitivity to the direction of the applied load relative to the wave. However, the range in which the bearing performance can be varied decreases as the number of waves increases. Therefore, both the number and the amplitude of the waves must be properly selected to optimize the wave bearing design for a specific application. It is concluded that the stiffness of an air journal bearing, due to hydrodynamic effect, could be doubled and made to run stably by using a six or eight wave geometry with a wave amplitude approximately half of the bearing radial clearance.

  15. Experimental study of laminated rubber bearings for earthquake isolation of buildings, 2

    International Nuclear Information System (INIS)

    Fujita, Takafumi; Fujita, Satoshi; Suzuki, Shigenobu; Yoshizawa, Toshikazu.

    1987-01-01

    Rubber bearings of 980 kN rated load were tested to investigate the characteristics of restoring forces of full scale bearings for earthquake isolation of buildings. These bearings comprising 27 natural rubber sheets of 6 mm thickness and 600 mm diameter bonded to steel plates were designed to provide a 100000 kg rated mass with a horizontal natural frequency of 0.51 Hz and a vertical one of 21 Hz and to accept a horizontal displacement larger than 300 mm. The static tests were carried out with satisfactory results. It was confirmed that the performance of the bearing met the specifications well. Furthermore, the vertical load distributions across the top plane of the bearing under various horizontal displacements were measured, and showed that they were always concentrated in the overlapping area of the top and bottom planes. This verified that the rubber bearing substantially supported the vertical load by the overlapping area. (author)

  16. Rolling-contact fatigue resistance of hard coatings on bearing steels.

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, A.

    1999-08-18

    Ball- and roller-bearings of the 21st Century are expected to perform better and last longer while operating under more stringent conditions than before. To meet these great expectations, researchers have been constantly exploring new bearing designs or refining existing ones, optimizing microstructure and chemistry of bearing materials, and alternatively, they have been considering the use of thin hard coatings for improved bearing performance and durability. Already, some laboratory tests have demonstrated that hard nitride, carbide (such as TiN, TiC, etc.) and diamondlike carbon (DLC) coatings can be very effective in prolonging the fatigue lives of bearing steels. This paper provides an overview of the recent developments in hard coatings for bearing applications. Previous studies have demonstrated that thin, hard coatings can effectively prolong the fatigue lives of bearing steel substrates. In particular, thinner hard coatings (i.e., 0.2 - 1 {micro}m thick) provide exceptional improvements in the fatigue lives of bearing steel substrates. In contrast, thicker hard coatings suffer micro fracture and delamination when tested under high contact stresses, hence are ineffective and may even have a negative effect on bearing life. Overall, it was concluded that thin hard coatings may offer new possibilities for bearing industry in meeting the performance and durability needs of the 21st Century.

  17. Seroprevalence of Toxoplasma gondii and Trichinella spiralis in North Carolina black bears (Ursus americanus).

    Science.gov (United States)

    Nutter, F B; Levine, J F; Stoskopf, M K; Gamble, H R; Dubey, J P

    1998-10-01

    Serum samples from 143 hunter-killed black bears were collected during the 1996 and 1997 black bear hunting seasons in eastern North Carolina. All samples were tested for antibodies to Toxoplasma gondii by the modified agglutination test. Antibodies to T. gondii were present in 120 of 143 (84%) bears. Females had significantly higher titers than males (Wilcoxon rank sums test, P = 0.045), and titers increased with age (Jonckheere test, P = 0.01). Samples collected during 1996 (n = 79) were tested for antibodies to Trichinella spiralis by enzyme-linked immunosorbent assay. No samples were positive for antibodies to T. spiralis.

  18. Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears

    OpenAIRE

    Cahill, James A; Stirling, Ian; Kistler, Logan; Salamzade, Rauf; Ersmark, Erik; Fulton, Tara L; Stiller, Mathias; Green, Richard E; Shapiro, Beth

    2015-01-01

    © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd. Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we...

  19. Little Bear Fire Summary Report

    Science.gov (United States)

    Sarah McCaffrey; Melanie Stidham; Hannah. Brenkert-Smith

    2013-01-01

    In June 2012, immediately after the Little Bear Fire burned outside Ruidoso, New Mexico, a team of researchers interviewed fire managers, local personnel, and residents to understand perceptions of the event itself, communication, evacuation, and pre-fire preparedness. The intensity of fire behavior and resulting loss of 242 homes made this a complex fire with a...

  20. BEAR AT THE BACK DOOR

    African Journals Online (AJOL)

    BEAR AT THE BACK DOOR. Deur generaal sir Walter Walker KCB, CBE,. D80. 8andton. Uitgegee deur Valiant Publis- hers. Verskyningsdatum Julie 1978. Prys R10.) Hierdie boek is 'n uitstekende aktuele geskrif ook. Suidelike Afrika se politieke en militere aspekte wat deur 'n a/gehele buitestaander nl 'n Britse. Generaal ...

  1. Climate Change, Polar Bears and their management

    OpenAIRE

    Derenchenko, Liza

    2010-01-01

    This is a literature study of polar bears in the context of climate change: what kind of creatures are polar bears, what are the main interpretations of current climate change, how might the polar bear adapt to these changes (feeding strategies) and how are the bears being managed (hunting)? These are relevant questions , since climate change is on the agenda, and polar bears being the apex predators of the Arctic are a key representation of the wildlife there. The third element of polar bear...

  2. 60NiTi Intermetallic Material Evaluation for Lightweight and Corrosion Resistant Spherical Sliding Bearings for Aerospace Applications

    Science.gov (United States)

    DellaCorte, Christopher; Jefferson, Michael

    2015-01-01

    NASA Glenn Research Center and the Kamatics subsidiary of the Kaman Corporation conducted the experimental evaluation of spherical sliding bearings made with 60NiTi inner races. The goal of the project was to assess the feasibility of manufacturing lightweight, corrosion resistant bearings utilizing 60NiTi for aerospace and industrial applications. NASA produced the bearings in collaboration with Abbott Ball Corporation and Kamatics fabricated bearing assemblies utilizing their standard reinforced polymer liner material. The assembled bearings were tested in oscillatory motion at a load of 4.54kN (10,000 lb), according to the requirements of the plain bearing specification SAE AS81820. Several test bearings were exposed to hydraulic fluid or aircraft deicing fluid prior to and during testing. The results show that the 60NiTi bearings exhibit tribological performance comparable to conventional stainless steel (440C) bearings. Further, exposure of 60NiTi bearings to the contaminant fluids had no apparent performance effect. It is concluded that 60NiTi is a feasible bearing material for aerospace and industrial spherical bearing applications.

  3. Superior long-term survival for fixed bearing compared with mobile bearing in ligament-balanced total knee arthroplasty.

    Science.gov (United States)

    Heesterbeek, P J C; van Houten, A H; Klenk, J S; Eijer, H; Christen, B; Wymenga, A B; Schuster, A J

    2018-05-01

    Only few long-term data on ligament-balanced cruciate-retaining total knee arthroplasty (CR TKA) are currently available. Either a mobile- or fixed-bearing insert can be chosen, which showed good mid-term outcome and few complications and revisions. This multi-centre retrospective cross-sectional cohort study investigated the 12-year results of primary TKA using a balancing gap technique and compared survival and clinical outcome between fixed and mobile inserts. In this retrospective cross-sectional cohort study, 557 cases of three clinics (2 Swiss, 1 Dutch) operated between 1998 and 2003 with the first series of a TKA implanted with a balanced gap technique (433 (77.7%) fixed, 124 (22.3%) mobile (anterior-posterior gliding (7-9 mm) and rotational (15°) degrees of freedom) inserts) were included for survival analysis (Kaplan-Meier, by insert type). At the 12-year follow-up (FU) examination of 189 cases, range of motion, knee society score (KSS), numeric rating scale (NRS) for pain and satisfaction were determined and radiographs were evaluated by median tests, by insert type. Of 521 cases available for analysis, 28 (5.4%; 11 fixed, 17 mobile bearing) were revised. Mean cumulative survival after 12.4 years was 97.0% (95% CI 94.7-98.4) for fixed bearings and 85.4% (95% CI 77.5-90.7) after 12.2 years for mobile bearings, p bearings. This study showed a superior survival for fixed bearing compared with mobile bearing in a CR TKA using a ligament-balanced technique after more than 12 years. Clinical outcomes are excellent to good after long-term follow-up, and similar for fixed and mobile bearing. Therapeutic studies-retrospective cohort study, Level III.

  4. Effects of Aversive Conditioning on Behavior of Nuisance Louisiana Black Bears

    OpenAIRE

    Leigh, Jennifer; Chamberlain, Michael J.

    2008-01-01

    Complaints associated with nuisance activity by Louisiana black bears (Ursus americanus luteolus) in south Louisiana have steadily increased since 2000, demanding intervention by state and federal agencies. As a federally threatened species, Louisiana black bears that are a nuisance require nonlethal management, referred to as aversive conditioning. We used rubber buckshot and dogs to test the effectiveness of management techniques used by the state of Louisiana to deter nuisance bear activit...

  5. Induction Motor Bearing Failure Detection and Diagnosis: Park and Concordia Transform Approaches Comparative Study

    OpenAIRE

    Önel, Izzet; Benbouzid, Mohamed

    2008-01-01

    International audience; This paper dealswith the problem of bearing failure detection and diagnosis in induction motors. Indeed, bearing deterioration is now the main cause of induction motor rotor failures. In this context, two fault detection and diagnosis techniques, namely the Park transform approach and the Concordia transform, are briefly presented and compared. Experimental tests, on a 0.75 kW two-pole induction motor with artificial bearing damage, outline the main features of the afo...

  6. Induction Motors Bearing Failures Detection and Diagnosis: Park and Concordia Transform Approaches Comparative Study

    OpenAIRE

    Önel, Izzet; Benbouzid, Mohamed

    2007-01-01

    International audience; This paper deals with the problem of bearing failure detection and diagnosis in induction motors. Indeed, bearings deterioration is now the main cause of induction motor rotor failures. In this context, two fault detection and diagnosis techniques, namely the Park transform approach and the Concordia transform, are briefly presented and compared. Experimental tests, on a 0.75-kW two-pole induction motor with artificial bearing damages, outline the above approaches main...

  7. Experimental Study of Geotextile Effect on Improving Soil Bearing Capacity in Aggregate Surfaced Roads

    OpenAIRE

    Mahdi Taghipour Masoumi; Ali Abdi Kordani; Mahmoud Nazirizad

    2017-01-01

    Geosynthetics utilization plays an important role in the construction of highways with no additive layers, such as asphalt concrete or cement concrete, or in a subgrade layer which affects the bearing capacity of unbounded layers. This laboratory experimental study was carried out to evaluate changes in the load bearing capacity of reinforced soil with these materials in highway roadbed with regard to geotextile properties. California Bearing Ratio (CBR) test samples were prepared with two ty...

  8. Gearbox Reliability Collaborative Investigation of High-Speed-Shaft Bearing Loads

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Guo, Yi [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-06-01

    The loads and contact stresses in the bearings of the high speed shaft section of the Gearbox Reliability Collaborative gearbox are examined in this paper. The loads were measured though strain gauges installed on the bearing outer races during dynamometer testing of the gearbox. Loads and stresses were also predicted with a simple analytical model and higher-fidelity commercial models. The experimental data compared favorably to each model, and bearing stresses were below thresholds for contact fatigue and axial cracking.

  9. BEARS: Radioactive ion beams at LBNL

    International Nuclear Information System (INIS)

    Powell, J.; Guo, F.Q.; Haustein, P.E.

    1998-01-01

    BEARS (Berkeley Experiments with Accelerated Radioactive Species) is an initiative to develop a radioactive ion-beam capability at Lawrence Berkeley National Laboratory. The aim is to produce isotopes at an existing medical cyclotron and to accelerate them at the 88 inch Cyclotron. To overcome the 300-meter physical separation of these two accelerators, a carrier-gas transport system will be used. At the terminus of the capillary, the carrier gas will be separated and the isotopes will be injected into the 88 inch Cyclotron's Electron Cyclotron Resonance (ECR) ion source. The first radioactive beams to be developed will include 20-min 11 C and 70-sec 14 O, produced by (p,n) and (p,α) reactions on low-Z targets. A test program is currently being conducted at the 88 inch Cyclotron to develop the parts of the BEARS system. Preliminary results of these tests lead to projections of initial 11 C beams of up to 2.5 x 10 7 ions/sec and 14 O beams of 3 x 10 5 ions/sec

  10. Journal and Wave Bearing Impedance Calculation Software

    Science.gov (United States)

    Hanford, Amanda; Campbell, Robert

    2012-01-01

    The wave bearing software suite is a MALTA application that computes bearing properties for user-specified wave bearing conditions, as well as plain journal bearings. Wave bearings are fluid film journal bearings with multi-lobed wave patterns around the circumference of the bearing surface. In this software suite, the dynamic coefficients are outputted in a way for easy implementation in a finite element model used in rotor dynamics analysis. The software has a graphical user interface (GUI) for inputting bearing geometry parameters, and uses MATLAB s structure interface for ease of interpreting data. This innovation was developed to provide the stiffness and damping components of wave bearing impedances. The computational method for computing bearing coefficients was originally designed for plain journal bearings and tilting pad bearings. Modifications to include a wave bearing profile consisted of changing the film thickness profile given by an equation, and writing an algorithm to locate the integration limits for each fluid region. Careful consideration was needed to implement the correct integration limits while computing the dynamic coefficients, depending on the form of the input/output variables specified in the algorithm.

  11. Development and Application of Integrated Aerodynamic Protuberant Foil Journal and Thrust Bearing in Turboexpander

    Directory of Open Access Journals (Sweden)

    Tianwei Lai

    2017-01-01

    Full Text Available Foil bearing provides compliant support and moderate Coulomb friction for rotor-bearing system, which is conducive to stability and reliability of high speed rotating machinery. In this paper, both hydrodynamic lubricated foil journal and foil thrust bearings are applied in a 150 m3·h−1 turboexpander for air separation. In the bearings, protuberant foil is chosen as the supporting subfoil due to its merits of easy fabrication and assembly. Static loading and deflection of the bearings are tested, respectively, before integration into the turboexpander. Afterwards, the loading and deflection curves of the journal and thrust bearings are polynomial fitted using least-square method. Then, performance tests are carried out on the rotor-bearing system, including transient speed-up, high speed, and speed-down processes. In the tests, the turboexpander supported by the hydrodynamic foil bearings operates smoothly with repeatability. Maximal rotor speed of the turboexpander reaches 52000 rpm with hydrodynamic lubricated protuberant foil bearings.

  12. Assessment on bearing capacity of buffer material to overpack

    International Nuclear Information System (INIS)

    Hirai, Takashi; Tanai, Kenji; Takaji, Kazuhiko; Ohnuma, Satoshi

    2003-02-01

    To objective of this report is to clarify the characteristics of the bearing capacity of the buffer material against the deformation of the overpack in the engineered barrier system. In the second progress report by JNC, it was reported that the well designed engineered barrier system is stable and safety on mechanical support of the overpack to ensure stability and stress which acts on the overpack by some analysis. However, the degree of the capacity to the ultimate state and the background data of the design are not necessary clarified in the report. Therefore it is considered to be important to assess the ultimate state and make the relationship clear between deformation and bearing capacity of the overpack in the engineered barrier system. So the scale test and the simulation analysis were carried out for the longitudinal deformation of the overpack in the saturated buffer material constrained by the host rock. From the result of the scale test and the analysis it appears that the bearing capacity is increasing with the deformation of the overpack even if the bearing capacity is over the yield force and the relationship between deformation and bearing capacity can be approximately expressed by the simple function. (author)

  13. Advanced Active-Magnetic-Bearing Thrust-Measurement System

    Science.gov (United States)

    Imlach, Joseph; Kasarda, Mary; Blumber, Eric

    2008-01-01

    An advanced thrust-measurement system utilizes active magnetic bearings to both (1) levitate a floating frame in all six degrees of freedom and (2) measure the levitation forces between the floating frame and a grounded frame. This system was developed for original use in measuring the thrust exerted by a rocket engine mounted on the floating frame, but can just as well be used in other force-measurement applications. This system offers several advantages over prior thrust-measurement systems based on mechanical support by flexures and/or load cells: The system includes multiple active magnetic bearings for each degree of freedom, so that by selective use of one, some, or all of these bearings, it is possible to test a given article over a wide force range in the same fixture, eliminating the need to transfer the article to different test fixtures to obtain the benefit of full-scale accuracy of different force-measurement devices for different force ranges. Like other active magnetic bearings, the active magnetic bearings of this system include closed-loop control subsystems, through which the stiffness and damping characteristics of the magnetic bearings can be modified electronically. The design of the system minimizes or eliminates cross-axis force-measurement errors. The active magnetic bearings are configured to provide support against movement along all three orthogonal Cartesian axes, and such that the support along a given axis does not produce force along any other axis. Moreover, by eliminating the need for such mechanical connections as flexures used in prior thrust-measurement systems, magnetic levitation of the floating frame eliminates what would otherwise be major sources of cross-axis forces and the associated measurement errors. Overall, relative to prior mechanical-support thrust-measurement systems, this system offers greater versatility for adaptation to a variety of test conditions and requirements. The basic idea of most prior active-magnetic-bearing

  14. Dynamics of gas-thrust bearings

    Science.gov (United States)

    Stiffler, A. K.; Tapia, R. R.

    1978-01-01

    Computer program calculates load coefficients, up to third harmonic, for hydrostatic gas thrust bearings. Program is useful in identification of industrial situations where gas-thrust bearings have potential applications.

  15. Rolling Element Bearing Stiffness Matrix Determination (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Y.; Parker, R.

    2014-01-01

    Current theoretical bearing models differ in their stiffness estimates because of different model assumptions. In this study, a finite element/contact mechanics model is developed for rolling element bearings with the focus of obtaining accurate bearing stiffness for a wide range of bearing types and parameters. A combined surface integral and finite element method is used to solve for the contact mechanics between the rolling elements and races. This model captures the time-dependent characteristics of the bearing contact due to the orbital motion of the rolling elements. A numerical method is developed to determine the full bearing stiffness matrix corresponding to two radial, one axial, and two angular coordinates; the rotation about the shaft axis is free by design. This proposed stiffness determination method is validated against experiments in the literature and compared to existing analytical models and widely used advanced computational methods. The fully-populated stiffness matrix demonstrates the coupling between bearing radial, axial, and tilting bearing deflections.

  16. Development of design method of thick rubber bearings for three-dimensional base isolation

    International Nuclear Information System (INIS)

    Yabana, Shuichi; Matuda, Akihiro

    2000-01-01

    Thick rubber bearings as 3-dimensional base isolators have been developed to reduce both horizontal and vertical seismic loads especially for equipment in Fast Breeder Reactors. In this report, a design method of thick rubber bearings is presented. To consider nonlinearity of vertical stiffness affected by vertical stress in the design of thick rubber bearings, Lindley's evaluation method of vertical stiffness is modified as an explicit form of vertical stress. We confirm that the presented method is efficient for design of the thick rubber bearings from comparing between test results and predicted values. Furthermore, rubber bearing tests are conducted with 1/3 scale models to evaluate mechanical properties of thick rubber bearings including ultimate limits. In the tests, horizontal and vertical characteristics of 1/3 scale model are compared with those of 1/6 scale model to discuss scale effect of test specimen. Ultimate limits such as failure shear strain of thick rubber bearings are obtained under various loading conditions. From the test results, we confirm that full scale thick rubber bearing to satisfy requirements is feasible. (author)

  17. Stable isotopes to detect food-conditioned bears and to evaluate human-bear management

    Science.gov (United States)

    Hopkins, John B.; Koch, Paul L.; Schwartz, Charles C.; Ferguson, Jake M.; Greenleaf, Schuyler S.; Kalinowski, Steven T.

    2012-01-01

    We used genetic and stable isotope analysis of hair from free-ranging black bears (Ursus americanus) in Yosemite National Park, California, USA to: 1) identify bears that consume human food, 2) estimate the diets of these bears, and 3) evaluate the Yosemite human–bear management program. Specifically, we analyzed the isotopic composition of hair from bears known a priori to be food-conditioned or non-food-conditioned and used these data to predict whether bears with an unknown management status were food-conditioned (FC) or non-food-conditioned (NFC). We used a stable isotope mixing model to estimate the proportional contribution of natural foods (plants and animals) versus human food in the diets of FC bears. We then used results from both analyses to evaluate proactive (population-level) and reactive (individual-level) human–bear management, and discussed new metrics to evaluate the overall human–bear management program in Yosemite. Our results indicated that 19 out of 145 (13%) unknown bears sampled from 2005 to 2007 were food-conditioned. The proportion of human food in the diets of known FC bears likely declined from 2001–2003 to 2005–2007, suggesting proactive management was successful in reducing the amount of human food available to bears. In contrast, reactive management was not successful in changing the management status of known FC bears to NFC bears, or in reducing the contribution of human food to the diets of FC bears. Nine known FC bears were recaptured on 14 occasions from 2001 to 2007; all bears were classified as FC during subsequent recaptures, and human–bear management did not reduce the amount of human food in the diets of FC bears. Based on our results, we suggest Yosemite continue implementing proactive human–bear management, reevaluate reactive management, and consider removing problem bears (those involved in repeated bear incidents) from the population.

  18. Mercury in polar bears from Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Lentfer, J.W.; Galster, W.A.

    1987-04-01

    Alaskan polar bear (Ursus maritimus) muscle and liver samples collected in 1972 were analyzed for total mercury. Bears north of Alaska had more mercury than bears west of Alaska. The only difference between young and adult animals was in the northern area where adults had more mercury in liver tissue than young animals. Levels were probably not high enough to be a serious threat to bears.

  19. Technology development for indigenous water lubricated bearings

    International Nuclear Information System (INIS)

    Limaye, P.K.; Soni, N.L.; Agrawal, R.G.

    2010-01-01

    Water Lubricated Bearings (WLB) are used in various mechanisms of fuel handling systems of PHWRs and AHWR. Availability and random failures of these bearings was a major factor in refuelling operations. Indigenous development of these bearings was taken up and 7 types of antifriction bearings in various sizes (totaling 37 variants) for PHWR, AHWR and Dhruva applications were successfully developed. This paper deals with various aspects of WLB development. (author)

  20. Use of commercial extenders and alternatives to prevent sperm agglutination for cryopreservation of brown bear semen.

    Science.gov (United States)

    Gomes-Alves, S; Alvarez, M; Nicolas, M; Lopez-Urueña, E; Martínez-Rodríguez, C; Borragan, S; de Paz, P; Anel, L

    2014-08-01

    The objective of this study was to evaluate different bovine and canine commercial semen extenders for cryopreservation of brown bear ejaculates and the effect of semen collection directly into extender on sperm agglutination. Semen samples were obtained by electroejaculation from 13 adult males. In experiment 1, eleven ejaculates from eight bears were used to evaluate Bioxcell and Andromed as extenders, whereas in experiment 2, nine ejaculates from six bears were used to evaluate Triladyl canine, CaniPro, and Extender 2 as extenders. An extender specifically developed for brown bears (Test-Tris-fructose-egg yolk-glycerol, TTF-ULE/bear) served as a control extender in both experiments. After thawing, total and progressive sperm motility and sperm viability were greater (P bear and Andromed extenders than for Bioxcell in experiment 1 and greater (P bear extender than for Triladyl Canine, CaniPro, and Extender 2 in experiment 2. In experiment 3, addition of handling extender (TTF-H) to the semen collection tube for eight ejaculates from seven bears resulted in less (P bear is the most suitable extender for brown bear semen cryopreservation, but comparable results can be obtained with the commercial extender Andromed. In addition, collection of ejaculates directly in TTF-H extender decreases sperm agglutination in fresh samples. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Dynamic Characteristics of Rotors on Passive and Active Thrust Fluid-film Bearings with Fixed Pads

    Directory of Open Access Journals (Sweden)

    Babin Alexander

    2018-01-01

    Full Text Available Application of fluid-film bearings in rotor machines in many cases could have no alternative due to obvious advantages when compared to roller element bearings. Integration of information technology in mechanical engineering resulting in emergence of a new field of research – mechatronic bearings which allowed tracking condition of the most important parts of a machine and adjusting operational parameters of the system. Application of servo valves to control the flow rate through a fluid-film bearing is the most universal and simple way of rotor’s position control due to relative simplicity of modelling and absence of need to radically change the design of conventional hydrodynamic bearings. In the present paper numerical simulations of passive (conventional as opposed to mechatronic and active hybrid thrust fluid-film bearings with a central feeding chamber are presented, that are parts of a mechatronic rotor-bearing node. Numerical model of an active thrust bearing is based on solution of equations of hydrodynamics, rotor dynamics and an additional model of a servo valve. Various types of control have been investigated: P, PI and PID control, and the dynamic behaviour of a system has been estimated under various loads, namely static, periodic and impulse. A design of a test rig has been proposed to study passive and active thrust fluid-film bearings aimed at, among other, validation of numerical results of active bearings simulation.

  2. Design and evaluation of a 3 million DN series-hybrid thrust bearing

    Science.gov (United States)

    Scibbe, H. W.; Winn, L. W.; Eusepi, M.

    1976-01-01

    The design and experimental evaluation of a series-hybrid thrust bearing, consisting of a 150-mm ball bearing and a centrifugally actuated, conical, fluid-film bearing, is presented. Tests were conducted up to 16,000 rpm and at this speed an axial load of 15,600 N (3500 lb) was safely supported by the hybrid bearing system. Through the series-hybrid bearing principle, the effective ball bearing speed was reduced to approximately one-half of the shaft speed. A speed reduction of this magnitude would result in a tenfold increase in the ball bearing fatigue life. A successful evaluation of fluid-film bearing lubricant supply failure was performed repeatedly at an operating speed of 10,000 rpm. A complete and smooth changeover to full-scale ball bearing operation was effected when the oil supply to the fluid-film bearing was cut off. Reactivation of the fluid-film oil supply system produced a flawless return to the original mode of hybrid operation.

  3. Using tri-axial accelerometers to identify wild polar bear behaviors

    Science.gov (United States)

    Pagano, Anthony M.; Rode, Karyn D.; Cutting, A.; Owen, M.A.; Jensen, S.; Ware, J.V.; Robbins, C.T.; Durner, George M.; Atwood, Todd C.; Obbard, M.E.; Middel, K.R.; Thiemann, G.W.; Williams, T.M.

    2017-01-01

    Tri-axial accelerometers have been used to remotely identify the behaviors of a wide range of taxa. Assigning behaviors to accelerometer data often involves the use of captive animals or surrogate species, as their accelerometer signatures are generally assumed to be similar to those of their wild counterparts. However, this has rarely been tested. Validated accelerometer data are needed for polar bears Ursus maritimus to understand how habitat conditions may influence behavior and energy demands. We used accelerometer and water conductivity data to remotely distinguish 10 polar bear behaviors. We calibrated accelerometer and conductivity data collected from collars with behaviors observed from video-recorded captive polar bears and brown bears U. arctos, and with video from camera collars deployed on free-ranging polar bears on sea ice and on land. We used random forest models to predict behaviors and found strong ability to discriminate the most common wild polar bear behaviors using a combination of accelerometer and conductivity sensor data from captive or wild polar bears. In contrast, models using data from captive brown bears failed to reliably distinguish most active behaviors in wild polar bears. Our ability to discriminate behavior was greatest when species- and habitat-specific data from wild individuals were used to train models. Data from captive individuals may be suitable for calibrating accelerometers, but may provide reduced ability to discriminate some behaviors. The accelerometer calibrations developed here provide a method to quantify polar bear behaviors to evaluate the impacts of declines in Arctic sea ice.

  4. Black Bear Reactions to Venomous and Non-venomous Snakes in Eastern North America

    Science.gov (United States)

    Rogers, Lynn L; Mansfield, Susan A; Hornby, Kathleen; Hornby, Stewart; Debruyn, Terry D; Mize, Malvin; Clark, Rulon; Burghardt, Gordon M

    2014-01-01

    Bears are often considered ecological equivalents of large primates, but the latter often respond with fear, avoidance, and alarm calls to snakes, both venomous and non-venomous, there is sparse information on how bears respond to snakes. We videotaped or directly observed natural encounters between black bears (Ursus americanus) and snakes. Inside the range of venomous snakes in Arkansas and West Virginia, adolescent and adult black bears reacted fearfully in seven of seven encounters upon becoming aware of venomous and non-venomous snakes; but in northern Michigan and Minnesota where venomous snakes have been absent for millennia, black bears showed little or no fear in four encounters with non-venomous snakes of three species. The possible roles of experience and evolution in bear reactions to snakes and vice versa are discussed. In all areas studied, black bears had difficulty to recognize non-moving snakes by smell or sight. Bears did not react until snakes moved in 11 of 12 encounters with non-moving timber rattlesnakes (Crotalus horridus) and four species of harmless snakes. However, in additional tests in this study, bears were repulsed by garter snakes that had excreted pungent anal exudates, which may help explain the absence of snakes, both venomous and harmless, in bear diets reported to date. PMID:25635152

  5. Stress Analysis and Fatigue Behaviour of PTFE-Bronze Layered Journal Bearing under Real-Time Dynamic Loading

    Science.gov (United States)

    Duman, M. S.; Kaplan, E.; Cuvalcı, O.

    2018-01-01

    The present paper is based on experimental studies and numerical simulations on the surface fatigue failure of the PTFE-bronze layered journal bearings under real-time loading. ‘Permaglide Plain Bearings P10’ type journal bearings were experimentally tested under different real time dynamic loadings by using real time journal bearing test system in our laboratory. The journal bearing consists of a PTFE-bronze layer approximately 0.32 mm thick on the steel support layer with 2.18 mm thick. Two different approaches have been considered with in experiments: (i) under real- time constant loading with varying bearing widths, (ii) under different real-time loadings at constant bearing widths. Fatigue regions, micro-crack dispersion and stress distributions occurred at the journal bearing were experimentally and theoretically investigated. The relation between fatigue region and pressure distributions were investigated by determining the circumferential pressure distribution under real-time dynamic loadings for the position of every 10° crank angles. In the theoretical part; stress and deformation distributions at the surface of the journal bearing analysed by using finite element methods to determine the relationship between stress and fatigue behaviour. As a result of this study, the maximum oil pressure and fatigue cracks were observed in the most heavily loaded regions of the bearing surface. Experimental results show that PTFE-Bronze layered journal bearings fatigue behaviour is better than the bearings include white metal alloy.

  6. Thin film superconductor magnetic bearings

    Science.gov (United States)

    Weinberger, Bernard R.

    1995-12-26

    A superconductor magnetic bearing includes a shaft (10) that is subject to a load (L) and rotatable around an axis of rotation, a magnet (12) mounted to the shaft, and a stator (14) in proximity to the shaft. The stator (14) has a superconductor thin film assembly (16) positioned to interact with the magnet (12) to produce a levitation force on the shaft (10) that supports the load (L). The thin film assembly (16) includes at least two superconductor thin films (18) and at least one substrate (20). Each thin film (18) is positioned on a substrate (20) and all the thin films are positioned such that an applied magnetic field from the magnet (12) passes through all the thin films. A similar bearing in which the thin film assembly (16) is mounted on the shaft (10) and the magnet (12) is part of the stator (14) also can be constructed.

  7. Passive Thermal Management of Foil Bearings

    Science.gov (United States)

    Bruckner, Robert J. (Inventor)

    2015-01-01

    Systems and methods for passive thermal management of foil bearing systems are disclosed herein. The flow of the hydrodynamic film across the surface of bearing compliant foils may be disrupted to provide passive cooling and to improve the performance and reliability of the foil bearing system.

  8. 49 CFR 229.64 - Plain bearings.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Plain bearings. 229.64 Section 229.64 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION....64 Plain bearings. A plain bearing box shall contain visible free oil and may not be cracked to the...

  9. Cool Polar Bears: Dabbing on the Texture

    Science.gov (United States)

    O'Connell, Jean

    2011-01-01

    In this article, the author describes how her second-graders created their cool polar bears. The students used the elements of shape and texture to create the bears. They used Monet's technique of dabbing paint so as to give the bear some texture on his fur.

  10. 14 CFR 23.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 23.623 Section 23.623... Bearing factors. (a) Each part that has clearance (free fit), and that is subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of normal relative motion. (b) For...

  11. 14 CFR 25.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 25.623 Section 25.623... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.623 Bearing factors. (a) Except... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  12. 14 CFR 27.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 27.623 Section 27.623... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction General § 27.623 Bearing factors. (a) Except... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  13. 14 CFR 29.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 29.623 Section 29.623... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.623 Bearing factors. (a... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  14. Fractal analysis of polar bear hairs

    Directory of Open Access Journals (Sweden)

    Wang Qing-Li

    2015-01-01

    Full Text Available Hairs of a polar bear (Ursus maritimus are of superior properties such as the excellent thermal protection. Why do polar bears can resist such cold environment? The paper concludes that its fractal porosity plays an important role, and its fractal dimensions are very close to the golden mean, 1.618, revealing the possible optimal structure of polar bear hair.

  15. Evaluation of the body bearing of high performance female volleyball players

    Directory of Open Access Journals (Sweden)

    Stech M.

    2010-09-01

    Full Text Available In the present paper the results of the study of body bearing in 12 high performance female volleyball players of polish team (TPS Rumia are presented. To estimate body bearing the New-York's test of the body bearing classification was used. The results of the study have shown that asymmetrical positions of volleyball players in the time of services and attacks are contributed to formed some asymmetrical disturbances of body bearing. At the majority of sportsmen it is exhibited in omitting the left brachium and the left blade, in a right-hand scoliosis, in the tendency to a platypodia. It requires use of special preventive and adjusting exercises.

  16. Influence of Journal Bearing Axial Grooves on the Dynamic Behavior of Horizontal Rotors

    Directory of Open Access Journals (Sweden)

    Miguel Angelo de Carvalho Michalski

    2006-01-01

    Full Text Available Journal bearing design and the lubricant characteristics are very influential in a rotating machine behaviour. The bearing geometry can drastically affect the lubricant flow and also the rotor dynamics. Approaching that issue, this paper presents an experimental study of the dynamic behavior of a horizontal rotor suported by journal bearings with semi-circular axial grooves. The journal bearings were manufactured with a varied number of axial grooves and a versatile test rig is used, making possible the analysis of different configurations. The acquired signals are analyzed with classical and non-linear tools and the differences among the rotors’ configurations can be shown.

  17. Microstructural degradation of bearing steels

    OpenAIRE

    Solano Alvarez, Wilberth

    2015-01-01

    The aim of the work presented in this thesis is to clarify one of the most fundamental aspects of fatigue damage in bearings steels through critical experiments, in particular whether damage in the form of cracks precedes hard “white-etching matter" formation, which is carbon supersaturated nanoscaled ferrite. Heat treatments have been designed to create four different crack types and distributions: scarce martensite plate cracks, fine grain boundary cracks, abundant martensite plate cracks, ...

  18. Seeded Fault Bearing Experiments: Methodology and Data Acquisition

    Science.gov (United States)

    2011-06-01

    performed, verification was made that there was a gap between the motor end weight and bearing under test mounting block to avoid rubbing . 10. The...THE PENTAGON WASHINGTON DC 20301-3080 1 US ARMY INFO SYS ENGRG CMND ATTN AMSEL IE TD F JENIA FT HUACHUCA AZ 85613-5300 6 US ARMY

  19. The Bearing Capacity of Circular Footings in Sand

    DEFF Research Database (Denmark)

    Krabbenhøft, Sven; Clausen, Johan; Damkilde, Lars

    2012-01-01

    dependent on the stress level and on the basis of the test results, a non linear Mohr failure criterion has been proposed. This yield criterion has been implemented in a finite element program and an analysis of the bearing capacity of a circular shaped model foundation, diameter 100mm, has been conducted...

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

    Science.gov (United States)

    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.

  1. The experimental study on efficiency improvement of turbo machinery supported with magnetic bearings

    International Nuclear Information System (INIS)

    Park, In Hwang; Park, Young Ho; Han, Dong Chul

    2007-01-01

    To implement a conventional electromagnetic bearing in small turbo machinery, it has problems such as load capacity and size. Therefore, in this paper, these problems are resolved by using a permanent magnet biased electromagnetic bearing as a thrust bearing of small turbo machinery. Because the flux path of the bearing is designed by reluctance path modulation using an electromagnet and a permanent magnet, the bearing improves upon non-linearity, power consumption, size and load capacity of a conventional electromagnetic bearing. Test rotating the shaft over 500,000DN were carried out to verify the performance of the proposed small turbo machinery. In addition, the relationships between mass flow rate and pressure rise were measured as changing the tip clearance to verify the feasibility of efficiency improvement and active surge control and these results were compared with theoretical results

  2. An energy kurtosis demodulation technique for signal denoising and bearing fault detection

    International Nuclear Information System (INIS)

    Wang, Wilson; Lee, Hewen

    2013-01-01

    Rolling element bearings are commonly used in rotary machinery. Reliable bearing fault detection techniques are very useful in industries for predictive maintenance operations. Bearing fault detection still remains a very challenging task especially when defects occur on rotating bearing components because the fault-related features are non-stationary in nature. In this work, an energy kurtosis demodulation (EKD) technique is proposed for bearing fault detection especially for non-stationary signature analysis. The proposed EKD technique firstly denoises the signal by using a maximum kurtosis deconvolution filter to counteract the effect of signal transmission path so as to highlight defect-associated impulses. Next, the denoised signal is modulated over several frequency bands; a novel signature integration strategy is proposed to enhance feature characteristics. The effectiveness of the proposed EKD fault detection technique is verified by a series of experimental tests corresponding to different bearing conditions. (paper)

  3. Thermohydrodynamic analysis of cryogenic liquid turbulent flow fluid film bearings, phase 2

    Science.gov (United States)

    Sanandres, Luis

    1994-01-01

    The Phase 2 (1994) Annual Progress Report presents two major report sections describing the thermal analysis of tilting- and flexure-pad hybrid bearings, and the unsteady flow and transient response of a point mass rotor supported on fluid film bearings. A literature review on the subject of two-phase flow in fluid film bearings and part of the proposed work for 1995 are also included. The programs delivered at the end of 1994 are named hydroflext and hydrotran. Both codes are fully compatible with the hydrosealt (1993) program. The new programs retain the same calculating options of hydrosealt plus the added bearing geometries, and unsteady flow and transient forced response. Refer to the hydroflext & hydrotran User's Manual and Tutorial for basic information on the analysis and instructions to run the programs. The Examples Handbook contains the test bearing cases along with comparisons with experimental data or published analytical values. The following major tasks were completed in 1994 (Phase 2): (1) extension of the thermohydrodynamic analysis and development of computer program hydroflext to model various bearing geometries, namely, tilting-pad hydrodynamic journal bearings, flexure-pad cylindrical bearings (hydrostatic and hydrodynamic), and cylindrical pad bearings with a simple elastic matrix (ideal foil bearings); (2) improved thermal model including radial heat transfer through the bearing stator; (3) calculation of the unsteady bulk-flow field in fluid film bearings and the transient response of a point mass rotor supported on bearings; and (4) a literature review on the subject of two-phase flows and homogeneous-mixture flows in thin-film geometries.

  4. Design and Experiment of Auxiliary Bearing for Helium Blower of HTR-PM

    International Nuclear Information System (INIS)

    Yang Guojun; Shi Zhengang; Liu Xingnan; Zhao Jingjing

    2014-01-01

    The helium blower is the important equipment for HTR-PM. Active magnetic bearing (AMB) instead of mechanical bearing is selected to support the rotor of the helium blower. However, one implication of AMB is the requirement to provide the auxiliary bearing to mitigate the effects of failures or overload conditions. The auxiliary bearing is used to support the rotor when the AMB fails to work. It must support the dropping rotor and bear the great impact force and friction heat. The design of the auxiliary bearing is one of the challenging problems in the whole system. It is very important for the helium blower with AMB of HTR-PM to make success. The rotor’s length of helium blower of HTR-PM is about 3.3 m, its weight is about 4000 kg and the rotating speed is 4000 r/min. The axial load is 4500kg, and the radial load is 1950kg. The angular contact ball bearing was selected as the auxiliary bearing. The test rig has been finished. It is difficult to analyze the falling course of the rotor. The preliminary analysis of the dropping rotor was done in the special condition. The impact force of auxiliary bearing was computed for the axial and radial load. And the dropping test of the blower rotor for HTR-10 will be introduced also in this paper. Results offer the important theoretical base for the protector design of the helium blower with AMB for HTR-PM. (author)

  5. Evaluation of erythrocyte flow at a bearing gap in a hydrodynamically levitated centrifugal blood pump.

    Science.gov (United States)

    Murashige, Tomotaka; Kosaka, Ryo; Sakota, Daisuke; Nishida, Masahiro; Kawaguchi, Yasuo; Yamane, Takashi; Maruyama, Osamu

    2015-01-01

    We have developed a hydrodynamically levitated centrifugal blood pump for extracorporeal circulatory support. In the blood pump, a spiral groove bearing was adopted for a thrust bearing. In the spiral groove bearing, separation of erythrocytes and plasma by plasma skimming has been postulated to occur. However, it is not clarified that plasma skimming occurs in a spiral groove bearing. The purpose of this study is to verify whether plasma skimming occurs in the spiral groove bearing of a hydrodynamically levitated centrifugal blood pump. For evaluation of plasma skimming in the spiral groove bearing, an impeller levitation performance test using a laser focus displacement meter and a microscopic visualization test of erythrocyte flow using a high-speed microscope were conducted. Bovine blood diluted with autologous plasma to adjust hematocrit to 1.0% was used as a working fluid. Hematocrit on the ridge region in the spiral groove bearing was estimated using image analysis. As a result, hematocrits on the ridge region with gaps of 45 μm, 31 μm, and 25 μm were calculated as 1.0%, 0.6%, and 0.3%, respectively. Maximum skimming efficiency in this study was calculated as 70% with a gap of 25 μm. We confirmed that separation of erythrocyte and plasma occurred in the spiral groove bearing with decrease in bearing gap in a hydrodynamically levitated centrifugal blood pump.

  6. Photos provide information on age, but not kinship, of Andean bear.

    Science.gov (United States)

    Van Horn, Russell C; Zug, Becky; Appleton, Robyn D; Velez-Liendo, Ximena; Paisley, Susanna; LaCombe, Corrin

    2015-01-01

    Using photos of captive Andean bears of known age and pedigree, and photos of wild Andean bear cubs camera trap photos are one of the most readily available sources of information on large cryptic mammals, we suggest that similar methods be tested for use in other poorly understood species.

  7. Experimental and theoretical study of friction torque from radial ball bearings

    Science.gov (United States)

    Geonea, Ionut; Dumitru, Nicolae; Dumitru, Ilie

    2017-10-01

    In this paper it is presented a numerical simulation and an experimental study of total friction torque from radial ball bearings. For this purpose it is conceived a virtual CAD model of the experimental test bench for bearing friction torque measurement. The virtual model it is used for numerical simulation in Adams software, that allows dynamic study of multi-body systems and in particularly with facility Adams Machinery of dynamic behavior of machine parts. It is manufactured an experimental prototype of the test bench for radial ball bearings friction torque measurement. In order to measure the friction torque of the tested bearings it is used an equal resistance elastic beam element, with strain gauge transducer to measure bending deformations. The actuation electric motor of the bench has the shaft mounted on two bearings and the motor housing is fixed to the free side of the elastic beam, which is bended by a force proportional with the total friction torque. The beam elastic element with strain gauge transducer is calibrated in order to measure the force occurred. Experimental determination of the friction torque is made for several progressive radial loads. It is established the correlation from the friction torque and bearing radial load. The bench allows testing of several types and dimensions of radial bearings, in order to establish the bearing durability and of total friction torque.

  8. PREVALENCE OF ANTIBODIES AGAINST TOXOPLASMA GONDII IN POLAR BEARS (URSUS MARITIMUS) FROM SVALBARD AND EAST GREENLAND

    Science.gov (United States)

    Serum samples from 419 polar bears (Ursus maritimus) from Svalbard and the Barents Sea (collected 1990 - 2000) and 108 polar bears from East Greenland (collected 1999 - 2004) were assayed for antibodies against Toxoplasma gondii using the modified agglutination test (MAT). Antibody prevalences were ...

  9. Method to Increase Performance of Foil Bearings Through Passive Thermal Management

    Science.gov (United States)

    Bruckner, Robert

    2013-01-01

    This invention is a new approach to designing foil bearings to increase their load capacity and improve their reliability through passive thermal management. In the present case, the bearing is designed in such a way as to prevent the carryover of lubricant from the exit of one sector to the inlet of the ensuing sector of the foil bearing. When such passive thermal management techniques are used, bearing load capacity is improved by multiples, and reliability is enhanced when compared to current foil bearings. This concept has recently been tested and validated, and shows that load capacity performance of foil bearings can be improved by a factor of two at relatively low speeds with potentially greater relative improvements at higher speeds. Such improvements in performance with respect to speed are typical of foil bearings. Additionally, operation of these newly conceived bearings shows much more reliability and repeatable performance. This trait can be exploited in machine design to enhance safety, reliability, and overall performance. Finally, lower frictional torque has been demonstrated when operating at lower (non-load capacity) loads, thus providing another improvement above the current state of the art. The objective of the invention is to incorporate features into a foil bearing that both enhance passive thermal management and temperature control, while at the same time improve the hydrodynamic (load capacity) performance of the foil bearing. Foil bearings are unique antifriction devices that can utilize the working fluid of a machine as a lubricant (typically air for turbines and motors, liquids for pumps), and as a coolant to remove excess energy due to frictional heating. The current state of the art of foil bearings utilizes forced cooling of the bearing and shaft, which represents poor efficiency and poor reliability. This invention embodies features that utilize the bearing geometry in such a manner as to both support load and provide an inherent and

  10. Scaling laws for radial foil bearings

    Science.gov (United States)

    Honavara Prasad, Srikanth

    The effects of fluid pressurization, structural deformation of the compliant members and heat generation in foil bearings make the design and analysis of foil bearings very complicated. The complex fluid-structural-thermal interactions in foil bearings also make modeling efforts challenging because these phenomena are governed by highly non-linear partial differential equations. Consequently, comparison of various bearing designs require detailed calculation of the flow fields (velocities, pressures), bump deflections (structural compliance) and heat transfer phenomena (viscous dissipation in the fluid, frictional heating, temperature profile etc.,) resulting in extensive computational effort (time/hardware). To obviate rigorous computations and aid in feasibility assessments of foil bearings of various sizes, NASA developed the "rule of thumb" design guidelines for estimation of journal bearing load capacity. The guidelines are based on extensive experimental data. The goal of the current work is the development of scaling laws for radial foil bearings to establish an analytical "rule of thumb" for bearing clearance and bump stiffness. The use of scale invariant Reynolds equation and experimentally observed NASA "rule of thumb" yield scale factors which can be deduced from first principles. Power-law relationships between: a. Bearing clearance and bearing radius, and b. bump stiffness and bearing radius, are obtained. The clearance and bump stiffness values obtained from scaling laws are used as inputs for Orbit simulation to study various cases. As the clearance of the bearing reaches the dimensions of the material surface roughness, asperity contact breaks the fluid film which results in wear. Similarly, as the rotor diameter increases (requiring larger bearing diameters), the load capacity of the fluid film should increase to prevent dry rubbing. This imposes limits on the size of the rotor diameter and consequently bearing diameter. Therefore, this thesis aims

  11. Improvement of journal bearing operation at heavy misalignment using bearing flexibility and compliant liners

    DEFF Research Database (Denmark)

    Thomsen, Kim; Klit, Peder

    2012-01-01

    A flexure journal bearing design is proposed that will improve operational behaviour of a journal bearing at pronounced misalignment. Using a thermoelastohydrodynamic model, it is shown that the proposed flexure journal bearing has vastly increased the hydrodynamic performance compared to the stiff...... bearing when misaligned. The hydrodynamic performance is evaluated on lubricant film thickness, pressure and temperature. Furthermore, the influence of a compliant bearing liner is investigated and it is found that it increases the hydrodynamic performance when applied to a stiff bearing, whereas...... the liner has practically no influence on the flexure journal bearing's performance....

  12. Nature vs. Nurture: Evidence for Social Learning of Conflict Behaviour in Grizzly Bears.

    Science.gov (United States)

    Morehouse, Andrea T; Graves, Tabitha A; Mikle, Nate; Boyce, Mark S

    2016-01-01

    The propensity for a grizzly bear to develop conflict behaviours might be a result of social learning between mothers and cubs, genetic inheritance, or both learning and inheritance. Using non-invasive genetic sampling, we collected grizzly bear hair samples during 2011-2014 across southwestern Alberta, Canada. We targeted private agricultural lands for hair samples at grizzly bear incident sites, defining an incident as an occurrence in which the grizzly bear caused property damage, obtained anthropogenic food, or killed or attempted to kill livestock or pets. We genotyped 213 unique grizzly bears (118 M, 95 F) at 24 microsatellite loci, plus the amelogenin marker for sex. We used the program COLONY to assign parentage. We evaluated 76 mother-offspring relationships and 119 father-offspring relationships. We compared the frequency of problem and non-problem offspring from problem and non-problem parents, excluding dependent offspring from our analysis. Our results support the social learning hypothesis, but not the genetic inheritance hypothesis. Offspring of problem mothers are more likely to be involved in conflict behaviours, while offspring from non-problem mothers are not likely to be involved in incidents or human-bear conflicts themselves (Barnard's test, p = 0.05, 62.5% of offspring from problem mothers were problem bears). There was no evidence that offspring are more likely to be involved in conflict behaviour if their fathers had been problem bears (Barnard's test, p = 0.92, 29.6% of offspring from problem fathers were problem bears). For the mother-offspring relationships evaluated, 30.3% of offspring were identified as problem bears independent of their mother's conflict status. Similarly, 28.6% of offspring were identified as problem bears independent of their father's conflict status. Proactive mitigation to prevent female bears from becoming problem individuals likely will help prevent the perpetuation of conflicts through social learning.

  13. Nature vs. nurture: Evidence for social learning of conflict behaviour in grizzly bears

    Science.gov (United States)

    Morehouse, Andrea T.; Graves, Tabitha A.; Mikle, Nathaniel; Boyce, Mark S.

    2016-01-01

    The propensity for a grizzly bear to develop conflict behaviours might be a result of social learning between mothers and cubs, genetic inheritance, or both learning and inheritance. Using non-invasive genetic sampling, we collected grizzly bear hair samples during 2011–2014 across southwestern Alberta, Canada. We targeted private agricultural lands for hair samples at grizzly bear incident sites, defining an incident as an occurrence in which the grizzly bear caused property damage, obtained anthropogenic food, or killed or attempted to kill livestock or pets. We genotyped 213 unique grizzly bears (118 M, 95 F) at 24 microsatellite loci, plus the amelogenin marker for sex. We used the program COLONY to assign parentage. We evaluated 76 mother-offspring relationships and 119 father-offspring relationships. We compared the frequency of problem and non-problem offspring from problem and non-problem parents, excluding dependent offspring from our analysis. Our results support the social learning hypothesis, but not the genetic inheritance hypothesis. Offspring of problem mothers are more likely to be involved in conflict behaviours, while offspring from non-problem mothers are not likely to be involved in incidents or human-bear conflicts themselves (Barnard’s test, p = 0.05, 62.5% of offspring from problem mothers were problem bears). There was no evidence that offspring are more likely to be involved in conflict behaviour if their fathers had been problem bears (Barnard’s test, p = 0.92, 29.6% of offspring from problem fathers were problem bears). For the mother-offspring relationships evaluated, 30.3% of offspring were identified as problem bears independent of their mother’s conflict status. Similarly, 28.6% of offspring were identified as problem bears independent of their father’s conflict status. Proactive mitigation to prevent female bears from becoming problem individuals likely will help prevent the perpetuation of conflicts through social learning.

  14. Nature vs. Nurture: Evidence for Social Learning of Conflict Behaviour in Grizzly Bears.

    Directory of Open Access Journals (Sweden)

    Andrea T Morehouse

    Full Text Available The propensity for a grizzly bear to develop conflict behaviours might be a result of social learning between mothers and cubs, genetic inheritance, or both learning and inheritance. Using non-invasive genetic sampling, we collected grizzly bear hair samples during 2011-2014 across southwestern Alberta, Canada. We targeted private agricultural lands for hair samples at grizzly bear incident sites, defining an incident as an occurrence in which the grizzly bear caused property damage, obtained anthropogenic food, or killed or attempted to kill livestock or pets. We genotyped 213 unique grizzly bears (118 M, 95 F at 24 microsatellite loci, plus the amelogenin marker for sex. We used the program COLONY to assign parentage. We evaluated 76 mother-offspring relationships and 119 father-offspring relationships. We compared the frequency of problem and non-problem offspring from problem and non-problem parents, excluding dependent offspring from our analysis. Our results support the social learning hypothesis, but not the genetic inheritance hypothesis. Offspring of problem mothers are more likely to be involved in conflict behaviours, while offspring from non-problem mothers are not likely to be involved in incidents or human-bear conflicts themselves (Barnard's test, p = 0.05, 62.5% of offspring from problem mothers were problem bears. There was no evidence that offspring are more likely to be involved in conflict behaviour if their fathers had been problem bears (Barnard's test, p = 0.92, 29.6% of offspring from problem fathers were problem bears. For the mother-offspring relationships evaluated, 30.3% of offspring were identified as problem bears independent of their mother's conflict status. Similarly, 28.6% of offspring were identified as problem bears independent of their father's conflict status. Proactive mitigation to prevent female bears from becoming problem individuals likely will help prevent the perpetuation of conflicts through social

  15. [Advances in studies on bear bile powder].

    Science.gov (United States)

    Zhou, Chao-fan; Gao, Guo-jian; Liu, Ying

    2015-04-01

    In this paper, a detailed analysis was made on relevant literatures about bear bile powder in terms of chemical component, pharmacological effect and clinical efficacy, indicating bear bile powder's significant pharmacological effects and clinical application in treating various diseases. Due to the complex composition, bear bile powder is relatively toxic. Therefore, efforts shall be made to study bear bile powder's pharmacological effects, clinical application, chemical composition and toxic side-effects, with the aim to provide a scientific basis for widespread reasonable clinical application of bear bile powder.

  16. Valve assembly having remotely replaceable bearings

    International Nuclear Information System (INIS)

    Johnson, E.R.; Tanner, D.E.

    1980-01-01

    A valve assembly having remotely replaceable bearings is disclosed wherein a valve disc is supported within a flow duct for rotation about a pair of axially aligned bearings, one of which is carried by a spindle received within a diametral bore in the valve disc, and the other of which is carried by a bearing support block releasably mounted on the duct circumferentially of an annular collar on the valve disc coaxial with its diametrical bore. The spindle and bearing support block are adapted for remote removal to facilitate servicing or replacement of the valve disc support bearings

  17. A motor with superconducting magnetic bearings

    International Nuclear Information System (INIS)

    Gladun, A.; Stoye, P.; Verges, P.; Gawalek, W.; Habisreuther, T.; Goernert, P.

    1993-01-01

    Superconducting bearings may be one of the most promising near term applications of HTSC. For use at liquid nitrogen temperature and below, they offer the advantage of lower energy consumption and higher reliability. Different bearing configurations have been proposed. But in order to substitute for conventional bearings a further increase in the critical current density of the superconductor and improved bearing concepts are necessary. For this it is necessary to take into account the peculiarities of the interaction between permanent magnets and bulk superconductors. As a contribution to this programme we present the model of a motor with superconducting magnetic bearings. (orig.)

  18. Heuristic explanation of journal bearing instability

    Science.gov (United States)

    Crandall, S. H.

    1982-01-01

    A fluid-filled journal bearing is viewed as a powerful pump circulating fluid around the annular space between the journal and the bearing. A small whirling motion of the journal generates a wave of thickness variation progressing around the channel. The hypothesis that the fluid flow drives the whirl whenever the mean of the pumped fluid velocity is greater than the peripheral speed of the thickness variation wave is discussed and compared with other simple explanations of journal bearing instability. It is shown that for non-cavitation long bearings the hypothesis predicts instability onset correctly for unloaded bearings but gradually overpredicts the onset speed as the load is increased.

  19. A reliability approach to machine tool bearings

    International Nuclear Information System (INIS)

    Jia Yazhou; Shen Guixiang; Jia Zhixin

    1995-01-01

    Based on the machine tool working characteristics, a method to determine the bearing dynamic load rating with a specified reliability is presented. Unlike the conventional methods for machine tool bearing design which are almost empirical, the proposed method is based on the bearing fatigue reliability. Also, unlike the common design methods of other industrial bearings which cannot consider the machine tool peculiarity, the obtained method is based on power and torque characteristics of machine tools. Designing the machine tool bearings by use of the method can obtain the expected reliability

  20. Ball Bearing Analysis with the ORBIS Tool

    Science.gov (United States)

    Halpin, Jacob D.

    2016-01-01

    Ball bearing design is critical to the success of aerospace mechanisms. Key bearing performance parameters, such as load capability, stiffness, torque, and life all depend on accurate determination of the internal load distribution. Hence, a good analytical bearing tool that provides both comprehensive capabilities and reliable results becomes a significant asset to the engineer. This paper introduces the ORBIS bearing tool. A discussion of key modeling assumptions and a technical overview is provided. Numerous validation studies and case studies using the ORBIS tool are presented. All results suggest the ORBIS code closely correlates to predictions on bearing internal load distributions, stiffness, deflection and stresses.

  1. Mechatronics Applied to Fluid Film Bearings: Towards More Efficient Machinery

    DEFF Research Database (Denmark)

    Cerda Varela, Alejandro Javier

    ; and the successful experimental application of this controllable machine element as a calibrated shaker, for rotordynamics parameter identification purposes. The theoretical model of the studied controllable bearing proves to be adequate to predict the static and thermal behavior of the bearing. Furthermore......The current trends regarding turbomachinery design and operation demand for an expansion of the operational boundaries of these mechanical systems, regarding production rate, reliability and adaptability. In order to face the new requirements, it is necessary to migrate towards a new concept, where...... of modifying the static, thermal and dynamic properties of the bearing, depending on the operational requirements at hand. The research activities carried out during the project included both theoretical as well as experimental investigations, using a test rig consisting of a rigid rotor supported by a tilting...

  2. Fault Diagnosis of Rolling Bearings Based on EWT and KDEC

    Directory of Open Access Journals (Sweden)

    Mingtao Ge

    2017-12-01

    Full Text Available This study proposes a novel fault diagnosis method that is based on empirical wavelet transform (EWT and kernel density estimation classifier (KDEC, which can well diagnose fault type of the rolling element bearings. With the proposed fault diagnosis method, the vibration signal of rolling element bearing was firstly decomposed into a series of F modes by EWT, and the root mean square, kurtosis, and skewness of the F modes were computed and combined into the feature vector. According to the characteristics of kernel density estimation, a classifier based on kernel density estimation and mutual information was proposed. Then, the feature vectors were input into the KDEC for training and testing. The experimental results indicated that the proposed method can effectively identify three different operative conditions of rolling element bearings, and the accuracy rates was higher than support vector machine (SVM classifier and back-propagation (BP neural network classifier.

  3. Development of a morphological convolution operator for bearing fault detection

    Science.gov (United States)

    Li, Yifan; Liang, Xihui; Liu, Weiwei; Wang, Yan

    2018-05-01

    This paper presents a novel signal processing scheme, namely morphological convolution operator (MCO) lifted morphological undecimated wavelet (MUDW), for rolling element bearing fault detection. In this scheme, a MCO is first designed to fully utilize the advantage of the closing & opening gradient operator and the closing-opening & opening-closing gradient operator for feature extraction as well as the merit of excellent denoising characteristics of the convolution operator. The MCO is then introduced into MUDW for the purpose of improving the fault detection ability of the reported MUDWs. Experimental vibration signals collected from a train wheelset test rig and the bearing data center of Case Western Reserve University are employed to evaluate the effectiveness of the proposed MCO lifted MUDW on fault detection of rolling element bearings. The results show that the proposed approach has a superior performance in extracting fault features of defective rolling element bearings. In addition, comparisons are performed between two reported MUDWs and the proposed MCO lifted MUDW. The MCO lifted MUDW outperforms both of them in detection of outer race faults and inner race faults of rolling element bearings.

  4. Use of lodgepole pine cover types by Yellowstone grizzly bears

    Science.gov (United States)

    Mattson, D.J.

    1997-01-01

    Lodgepole pine (Pinus contorta) forests are a large and dynamic part of grizzly bear (Ursus arctos) habitat in the Yellowstone ecosystem. Research in other areas suggests that grizzly bears select for young open forest stands, especially for grazing and feeding on berries. Management guidelines accordingly recommend timber harvest as a technique for improving habitat in areas potentially dominated by lodgepole pine. In this paper I examine grizzly bear use of lodgepole pine forests in the Yellowstone area, and test several hypotheses with relevance to a new generation of management guidelines. Differences in grizzly bear selection of lodgepole pine cover types (defined on the basis of stand age and structure) were not pronounced. Selection furthermore varied among years, areas, and individuals. Positive selection for any lodgepole pine type was uncommon. Estimates of selection took 5-11 years or 4-12 adult females to stabilize, depending upon the cover type. The variances of selection estimates tended to stabilize after 3-5 sample years, and were more-or-less stable to slightly increasing with progressively increased sample area. There was no conclusive evidence that Yellowstone's grizzlies favored young (<40 yr) stands in general or for their infrequent use of berries. On the other hand, these results corroborated previous observations that grizzlies favored open and/or young stands on wet and fertile sites for grazing. These results also supported the proposition that temporally and spatially robust inferences require extensive, long-duration studies, especially for wide-ranging vertebrates like grizzly bears.

  5. Seismic isolation of nuclear power plants using elastomeric bearings

    Science.gov (United States)

    Kumar, Manish

    Seismic isolation using low damping rubber (LDR) and lead-rubber (LR) bearings is a viable strategy for mitigating the effects of extreme earthquake shaking on safety-related nuclear structures. Although seismic isolation has been deployed in nuclear structures in France and South Africa, it has not seen widespread use because of limited new build nuclear construction in the past 30 years and a lack of guidelines, codes and standards for the analysis, design and construction of isolation systems specific to nuclear structures. The nuclear accident at Fukushima Daiichi in March 2011 has led the nuclear community to consider seismic isolation for new large light water and small modular reactors to withstand the effects of extreme earthquakes. The mechanical properties of LDR and LR bearings are not expected to change substantially in design basis shaking. However, under shaking more intense than design basis, the properties of the lead cores in lead-rubber bearings may degrade due to heating associated with energy dissipation, some bearings in an isolation system may experience net tension, and the compression and tension stiffness may be affected by the horizontal displacement of the isolation system. The effects of intra-earthquake changes in mechanical properties on the response of base-isolated nuclear power plants (NPPs) were investigated using an advanced numerical model of a lead-rubber bearing that has been verified and validated, and implemented in OpenSees and ABAQUS. A series of experiments were conducted at University at Buffalo to characterize the behavior of elastomeric bearings in tension. The test data was used to validate a phenomenological model of an elastomeric bearing in tension. The value of three times the shear modulus of rubber in elastomeric bearing was found to be a reasonable estimate of the cavitation stress of a bearing. The sequence of loading did not change the behavior of an elastomeric bearing under cyclic tension, and there was no

  6. Improvement of journal bearing operation at heavy misalignment using bearing flexibility and compliant liners

    OpenAIRE

    Thomsen, Kim; Klit, Peder

    2012-01-01

    A flexure journal bearing design is proposed that will improve operational behaviour of a journal bearing at pronounced misalignment. Using a thermoelastohydrodynamic model, it is shown that the proposed flexure journal bearing has vastly increased the hydrodynamic performance compared to the stiff bearing when misaligned. The hydrodynamic performance is evaluated on lubricant film thickness, pressure and temperature. Furthermore, the influence of a compliant bearing liner is investigated and...

  7. Coupled Dynamics of a Rotor-Journal Bearing System Equipped with Thrust Bearings

    OpenAIRE

    Yu Lie; R.B. Bhat

    1995-01-01

    The rotordynamic coefficients of fixed-pad thrust bearing are introduced and calculated by using the out-domain method, and a general analysis method is developed to investigate the coupled dynamics of a rotor equipped with journal and thrust bearings simultaneously. Considerations include the effects of static tilt parameters of the rotor on rotordynamic coefficients of thrust bearing and the action of thrust bearing on system dynamics. It is shown that thrust bearing changes the load distri...

  8. A prototype construction of bearing heater system

    International Nuclear Information System (INIS)

    Firman Silitonga

    2007-01-01

    A bearing heater system has been successfully constructed using transformer-like method of 1000 VA power, 220 V primary voltage, and 50 Hz electrical frequency. The bearing heater consists of primary coil 230 turns, U type and bar-type iron core with 36 cm 2 , 9 cm 2 ,and 3 cm 2 cross-section, and electrical isolation. The bearing heater is used to enlarge the diameter of the bearing so that it can be easily fixed on an electric motor shaft during replacement because the heating is conducted by treated the bearing as a secondary coil of a transformer. This bearing heater can be used for bearing with 3 and 6 cm of inner diameter and 12 cm of maximum outside diameter. (author)

  9. Noise of oil lubricated journal bearings

    International Nuclear Information System (INIS)

    Rho, Byoung Hoo; Kim, Kyung Woong

    2002-01-01

    The purpose of the paper is to provide a procedure to calculate the noise of oil lubricated journal bearings. To do this, the nonlinear transient analysis of rotor-bearing system including rotor imbalance is performed. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Furthermore, a transmission theory of plane waves on a boundary of the outer surface of the bearing is used to obtain the sound pressure level of the bearing. Results show that the sound pressure level of the bearing can be increased with the rotational speed of the rotor although the whirl amplitude of the rotor is decreased at high speed. Noise estimating procedures presented in this paper could be an aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings

  10. Evaluation of rotating, incompressibly lubricated, pressurized thrust bearings

    Science.gov (United States)

    Fleming, D. P.

    1971-01-01

    Program evaluates a series hybrid, fluid film ball bearing consisting of an orifice compensated pressurized thrust bearing in conjunction with a self-acting journal bearing. Oil viscosities corresponding to experimentally measured ball bearing outer-race temperatures were used.

  11. The influence of the lubricant film on the stiffness and damping characteristics of a deep groove ball bearing

    Science.gov (United States)

    Jacobs, William; Boonen, Rene; Sas, Paul; Moens, David

    2014-01-01

    This paper experimentally investigates the formation of a lubricant film in a deep groove ball bearing and its effect on the bearing dynamics. A novel test rig is introduced, which allows testing different types and sizes of bearings in real-life conditions. The test rig dynamics are optimised such that the dynamic properties of the bearing are measured in a frequency range below the resonances of the flexible modes. Two properties of the bearing, both its stiffness and damping value in the direction of the static bearing load, are identified. The behaviour of the lubricant film between the rolling elements and raceways is measured based on the electrical resistance through the bearing. For this purpose, the bearing housing is electrically isolated from the surrounding structure. The electrical resistance, stiffness and damping of the test bearing are identified during a speed run-up. The influence of the bearing temperature is analysed as well. During a run-up at constant bearing temperature, the measurement of the electrical resistance describes the formation of the lubricant film. Due to the formation of the lubricant film, the bearing stiffness increases by 3.2% while the damping increases by 24%. During a warm-up of the bearing, the viscosity of the lubricant film decreases strongly. A resulting decrease in electrical resistance, stiffness and damping is measured. Finally, the electrical resistance, stiffness and damping are identified at different speeds, after the bearing has reached a stable temperature at each speed. A combined effect of both rotation and temperature is observed and discussed.

  12. Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears.

    Science.gov (United States)

    Cahill, James A; Stirling, Ian; Kistler, Logan; Salamzade, Rauf; Ersmark, Erik; Fulton, Tara L; Stiller, Mathias; Green, Richard E; Shapiro, Beth

    2015-03-01

    Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we present an analysis of data from a large panel of polar bear and brown bear genomes that includes brown bears from the ABC islands, the Alaskan mainland and Europe. Our results provide clear evidence that gene flow between the two species had a geographically wide impact, with polar bear DNA found within the genomes of brown bears living both on the ABC islands and in the Alaskan mainland. Intriguingly, while brown bear genomes contain up to 8.8% polar bear ancestry, polar bear genomes appear to be devoid of brown bear ancestry, suggesting the presence of a barrier to gene flow in that direction. © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  13. Concept for a new hydrodynamic blood bearing for miniature blood pumps.

    Science.gov (United States)

    Kink, Thomas; Reul, Helmut

    2004-10-01

    The most crucial element of a long-term implantable rotary blood pump is the rotor bearing. Because of heat generation and power loss resulting from friction, seals within the devices have to be avoided. Actively controlled magnetic bearings, although maintenance-free, increase the degree of complexity. Hydrodynamic bearings for magnetically coupled rotors may offer an alternative solution to this problem. Additionally, for miniature pumps, the load capacity of hydrodynamic bearings scales slower than that of, for example, magnetic bearings because of the cube-square-law. A special kind of hydrodynamic bearing is a spiral groove bearing (SGB), which features an excellent load capacity. Mock-loop tests showed that SGBs do not influence the hydraulic performance of the tested pumps. Although, as of now, the power consumption of the SBG is higher than for a mechanical pivot bearing, it is absolutely contact-free and has an unlimited lifetime. The liftoff of the rotor occurs already at 10% of design speed. Further tests and flow visualization studies on scaled-up models must demonstrate its overall blood compatibility.

  14. Thermal Effects on the Bearing Behavior of Composite Joints

    Science.gov (United States)

    Walker, Sandra Polesky

    2001-01-01

    Thermal effects on the pin-bearing behavior of an IM7/PET15 composite laminate are studied comprehensively. A hypothesis presents factors influencing a change in pin-bearing strength with a change in temperature for a given joint design. The factors include the change in the state of residual cure stress, the material properties, and the fastener fit with a change in temperature. Experiments are conducted to determine necessary lamina and laminate material property data for the IM7/PET15 being utilized in this study. Lamina material properties are determined between the assumed stress free temperature of 460 F down to -200 F. Laminate strength properties are determined for several lay-ups at the operating temperatures of 350 F, 70 F, and -200 F. A three-dimensional finite element analysis model of a composite laminate subject to compressive loading is developed. Both the resin rich layer located between lamina and the thermal residual stresses present in the laminate due to curing are determined to influence the state of stress significantly. Pin-bearing tests of several lay-ups were conducted to develop an understanding on the effect of temperature changes on the pin-bearing behavior of the material. A computational study investigating the factors influencing pin-bearing strength was performed. A finite element model was developed and used to determine the residual thermal cure stresses in the laminate containing a hole. Very high interlaminar stress concentrations were observed two elements away from the hole boundary at all three operating temperatures. The pin-bearing problem was modeled assuming a rigid frictionless pin and restraining only radial displacements at the hole boundary. A uniform negative pressure load was then applied to the straight end of the model. A solution, where thermal residual stresses were combined with the state of stress due to pin-bearing loads was evaluated. The presence of thermal residual stresses intensified the interlaminar

  15. Conditioning of alpha bearing wastes

    International Nuclear Information System (INIS)

    1991-01-01

    Alpha bearing wastes are generated during the reprocessing of spent fuel, mixed oxide fuel fabrication, decommissioning and other activities. The safe and effective management of these wastes is of particular importance owing to the radiotoxicity and long lived characteristics of certain transuranic (TRU) elements. The management of alpha bearing wastes involves a number of stages which include collection, characterization, segregation, treatment, conditioning, transport, storage and disposal. This report describes the currently available matrices and technologies for the conditioning of alpha wastes and relates them to their compatibility with the other stages of the waste management process. The selection of a specific immobilization process is dependent on the waste treatment state and the subsequent handling, transport, storage and disposal requirements. The overall objectives of immobilization are similar for all waste producers and processors, which are to produce: (a) Waste forms with sufficient mechanical, physical and chemical stability to satisfy all stages of handling, transport and storage (referred to as the short term requirements), and (b) Waste forms which will satisfy disposal requirements and inhibit the release of radionuclides to the biosphere (referred to as the long term requirements). Cement and bitumen processes have already been successfully applied to alpha waste conditioning on the industrial scale in many of the IAEA Member States. Cement systems based on BFS and pozzolanic cements have emerged as the principal encapsulation matrices for the full range of alpha bearing wastes. Alternative technologies, such as polymers and ceramics, are being developed for specific waste streams but are unlikely to meet widespread application owing to cost and process complexity. The merits of alpha waste conditioning are improved performance in transport, storage and disposal combined with enhanced public perception of waste management operations. These

  16. Evaluation of Grooved Solid Lubricated Bearings

    Science.gov (United States)

    1976-02-01

    support to this program; to Mr. D. B. El kins who balanced the solid lubri- cated bearing retainers and test rig drive shaft, and to various members...0.1 * ///o lo KY * el V M^° 3« ffr •> o-t z- i’fO * v • • /5T * 0-1 1/ 𔃻 14.4.U \\M» _5L? IVf c? a ft -a..( 1 7S°C Ml* fi H6 -o.« t 1 1 1... tifo ’’tMMMi psi LBS PSI i£f /./?. a^- RfADIMS /IY-OZ fifiw Hi 75 » 7f - - /«"". .Jfo lo ?•? tt 1 0.1 V oft" U - — • « n 󈧅 * 1 atoo - ’S

  17. Magnetic remanence of hematite-bearing murals

    Science.gov (United States)

    Lanza, R.; Zanella, E.; Saudino, S.

    2009-12-01

    We report on a series of experiments designed to test the ability of hematite-bearing colors to record the direction of the ambient magnetic field. Plasterboards accurately oriented with respect to the Earth's magnetic field were painted with red tempera colors prepared with hematite pigments. Magnetic measurements indicate that the color film retains a remanent magnetization and acquires a well developed magnetic fabric. The remanence direction is close to, yet slightly deviated from the Earth's magnetic field. The deviation is interpreted to result from preferential alignment of the pigment grains parallel to the plasterboard surface and depends on both its orientation with respect to magnetic north and the degree of magnetic anisotropy of the color film, which in turn varies according to the pigment used. Investigation of the magnetic remanence of murals may complement archaeomagnetic information derived from traditional materials such as baked and fired structures.

  18. Minuteman III Motor-Generator Bearing Grease Replacement

    Science.gov (United States)

    2013-07-01

    Automotive -40 to 170 °C MIL-PRF-10924H (GAA-H) PAO + Polyol ester Lithium complex Automotive multipurpose -54 to 180 °C MIL-PRF-81322G... Protection in Humidity Cabinet (ASTM D 1748) (8) Copper corrosion test (ASTM D 130) (9) Bimetallic corrosion test (ASTM D6547) (10) Low temperature...rust on bearing surfaces and to preserve grease consistency. In the corrosion protection property, the Multifak AFB2 grease showed very poor rust

  19. Precision magnetic suspension linear bearing

    Science.gov (United States)

    Trumper, David L.; Queen, Michael A.

    1992-01-01

    We have shown the design and analyzed the electromechanics of a linear motor suitable for independently controlling two suspension degrees of freedom. This motor, at least on paper, meets the requirements for driving an X-Y stage of 10 Kg mass with about 4 m/sq sec acceleration, with travel of several hundred millimeters in X and Y, and with reasonable power dissipation. A conceptual design for such a stage is presented. The theoretical feasibility of linear and planar bearings using single or multiple magnetic suspension linear motors is demonstrated.

  20. Experimental Investigation of Bearing Slip in a Wind Turbine Gearbox During a Transient Grid Loss Event

    Energy Technology Data Exchange (ETDEWEB)

    Helsen, Jan; Guo, Yi; Keller, Jonathan; Guillaume, Patrick

    2016-12-01

    This work investigates the behaviour of the high speed stage of a wind turbine gearbox during a transient grid loss event. Dynamometer testing on a full scale wind turbine nacelle is used. A combination of external and internal gearbox measurements is analysed. Particular focus is on the characterization of the high speed shaft tapered roller bearing slip behaviour. This slipping behaviour is linked to dynamic events by many researchers and described as potential bearing failure initiator. However only limited full scale dynamic testing is documented. Strain gauge bridges in grooves along the circumference of the outer ring are used to characterize the bearing behaviour in detail. It is shown that during the transient event the high speed shaft experiences a combined torsional and bending deformation. These unfavourable loading conditions induce roller slip in the bearings during the torque reversals indicating the potential of the applied load case to go beyond the preload of the tapered roller bearing.

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

    Science.gov (United States)

    Schuller, F. T.

    1973-01-01

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

  2. Development of aerodynamic bearing support for application in air cycle machines

    Directory of Open Access Journals (Sweden)

    Šimek J.

    2014-06-01

    Full Text Available Air cycle machines (ACM are used in environmental control system of aircrafts to manage pressurization of the cabin. The aim of this work is to gain theoretical and experimental data enabling replacement of rolling bearings, which require lubrication and have limited operating speed, with aerodynamic bearing support. Aerodynamic bearings do not pollute process air and at the same time allow achieving higher operating speed, thus enabling to reduce machine mass and dimensions. A test stand enabling the verification of aerodynamic bearing support properties for prospective ACM was designed, manufactured and tested with operating speeds up to 65 000 rpm. Some interesting features of the test stand design and the test results are presented. A smaller test stand with operating speed up to 100 000 rpm is in design stage.

  3. Study on load-bearing characteristics of a new pile group foundation for an offshore wind turbine.

    Science.gov (United States)

    Lang, Ruiqing; Liu, Run; Lian, Jijian; Ding, Hongyan

    2014-01-01

    Because offshore wind turbines are high-rise structures, they transfer large horizontal loads and moments to their foundations. One of the keys to designing a foundation is determining the sensitivities and laws affecting its load-bearing capacity. In this study, this procedure was carried out for a new high-rise cap pile group foundation adapted to the loading characteristics of offshore wind turbines. The sensitivities of influential factors affecting the bearing properties were determined using an orthogonal test. Through a combination of numerical simulations and model tests, the effects of the inclination angle, length, diameter, and number of side piles on the vertical bearing capacity, horizontal bearing capacity, and bending bearing capacity were determined. The results indicate that an increase in the inclination angle of the side piles will increase the vertical bearing capacity, horizontal bearing capacity, and bending bearing capacity. An increase in the length of the side piles will increase the vertical bearing capacity and bending bearing capacity. When the length of the side piles is close to the central pile, the increase is more apparent. Finally, increasing the number of piles will increase the horizontal bearing capacity; however, the growth rate is small because of the pile group effect.

  4. Study on Load-Bearing Characteristics of a New Pile Group Foundation for an Offshore Wind Turbine

    Science.gov (United States)

    Liu, Run; Lian, Jijian; Ding, Hongyan

    2014-01-01

    Because offshore wind turbines are high-rise structures, they transfer large horizontal loads and moments to their foundations. One of the keys to designing a foundation is determining the sensitivities and laws affecting its load-bearing capacity. In this study, this procedure was carried out for a new high-rise cap pile group foundation adapted to the loading characteristics of offshore wind turbines. The sensitivities of influential factors affecting the bearing properties were determined using an orthogonal test. Through a combination of numerical simulations and model tests, the effects of the inclination angle, length, diameter, and number of side piles on the vertical bearing capacity, horizontal bearing capacity, and bending bearing capacity were determined. The results indicate that an increase in the inclination angle of the side piles will increase the vertical bearing capacity, horizontal bearing capacity, and bending bearing capacity. An increase in the length of the side piles will increase the vertical bearing capacity and bending bearing capacity. When the length of the side piles is close to the central pile, the increase is more apparent. Finally, increasing the number of piles will increase the horizontal bearing capacity; however, the growth rate is small because of the pile group effect. PMID:25250375

  5. Admixture and gene flow from Russia in the recovering Northern European brown bear (Ursus arctos).

    Science.gov (United States)

    Kopatz, Alexander; Eiken, Hans Geir; Aspi, Jouni; Kojola, Ilpo; Tobiassen, Camilla; Tirronen, Konstantin F; Danilov, Pjotr I; Hagen, Snorre B

    2014-01-01

    Large carnivores were persecuted to near extinction during the last centuries, but have now recovered in some countries. It has been proposed earlier that the recovery of the Northern European brown bear is supported by migration from Russia. We tested this hypothesis by obtaining for the first time continuous sampling of the whole Finnish bear population, which is located centrally between the Russian and Scandinavian bear populations. The Finnish population is assumed to experience high gene flow from Russian Karelia. If so, no or a low degree of genetic differentiation between Finnish and Russian bears could be expected. We have genotyped bears extensively from all over Finland using 12 validated microsatellite markers and compared their genetic composition to bears from Russian Karelia, Sweden, and Norway. Our fine masked investigation identified two overlapping genetic clusters structured by isolation-by-distance in Finland (pairwise FST = 0.025). One cluster included Russian bears, and migration analyses showed a high number of migrants from Russia into Finland, providing evidence of eastern gene flow as an important driver during recovery. In comparison, both clusters excluded bears from Sweden and Norway, and we found no migrants from Finland in either country, indicating that eastern gene flow was probably not important for the population recovery in Scandinavia. Our analyses on different spatial scales suggest a continuous bear population in Finland and Russian Karelia, separated from Scandinavia.

  6. Serosurvey for selected pathogens in free-ranging American black bears (Ursus americanus) in Maryland, USA.

    Science.gov (United States)

    Bronson, Ellen; Spiker, Harry; Driscoll, Cindy P

    2014-10-01

    American black bears (Ursus americanus) in Maryland, USA, live in forested areas in close proximity to humans and their domestic pets. From 1999 to 2011, we collected 84 serum samples from 63 black bears (18 males; 45 females) in five Maryland counties and tested them for exposure to infectious, including zoonotic, pathogens. A large portion of the bears had antibody to canine distemper virus and Toxoplasma gondii, many at high titers. Prevalences of antibodies to zoonotic agents such as rabies virus and to infectious agents of carnivores including canine adenovirus and canine parvovirus were lower. Bears also had antibodies to vector-borne pathogens common to bears and humans such as West Nile virus, Borrelia burgdorferi, Rickettsia rickettsii, and Anaplasma phagocytophilum. Antibodies were detected to Leptospira interrogans serovars Pomona, Icterohaemorrhagiae, Canicola, Grippotyphosa, and Bratislava. We did not detect antibodies to Brucella canis or Ehrlichia canis. Although this population of Maryland black bears demonstrated exposure to multiple pathogens of concern for humans and domesticated animals, the low levels of clinical disease in this and other free-ranging black bear populations indicate the black bear is likely a spillover host for the majority of pathogens studied. Nevertheless, bear populations living at the human-domestic-wildlife interface with increasing human and domestic animal exposure should continue to be monitored because this population likely serves as a useful sentinel of ecosystem health.

  7. Establishing design criteria for crankshaft thrust bearings in gasoline and diesel engines by computer simulations and experiments. Crankshaft thrust bearing design - final report; Auslegungskriterien fuer Kurbelwellenaxiallager in Otto- und Dieselmotoren durch rechnergestuetzte Simulation und experimentelle Untersuchungen. Axialgleitlagerauslegung - Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Hunsicker, W. [Fachhochschule Mannheim (Germany). Inst. fuer Tribologie; Backhaus, K. [Univ. GH Kassel (Germany). Inst. fuer Maschinenelemente und Konstruktionstechnik; Schubert, W. [KS Gleitlager GmbH, Papenburg (Germany)

    2004-07-01

    Aim of the research-project was it to increase the calculation safety of crank shaft thrust bearings in combustion engines. The project was divided in two parts: (1) A simulation program to analyze the load bearing capacity of axial bearings under mixed lubrication has been developed at the Institut fuer Maschinenelemente und Konstruktionstechnik, University of Kassel. This part of the research-project has been presented at the FVV Herbsttagung in 2003. (2) The test runs with original parts were carried out on a newly designed thrust bearing test rig at the Institut fuer Tribologie, University of Applied Sciences in Mannheim. The following presentation shows the results of part 2. The experimental results show the influence of rotational frequency, load, bearing material, lateral run-out of the tread of the crankshaft and groove pattern. These test runs will help to dimension thrust bearings more efficiently. (orig.)

  8. Comparison of Alignment Correction Angles Between Fixed-Bearing and Mobile-Bearing UKA.

    Science.gov (United States)

    Inoue, Atsuo; Arai, Yuji; Nakagawa, Shuji; Inoue, Hiroaki; Yamazoe, Shoichi; Kubo, Toshikazu

    2016-01-01

    Good outcomes have been reported with both fixed-bearing and mobile-bearing unicompartmental knee arthroplasty (UKA). However, overcorrected alignment could induce the progression of arthritis on the non-arthroplasty side. Changes of limb alignment after UKA with both types of bearings (fixed bearing: 24 knees, mobile bearing: 28 knees) were investigated. The mean difference between the preoperative standing femoral-tibial angle (FTA) and postoperative standing FTA was significantly larger in mobile bearing UKA group. In fixed-bearing UKA, there must be some laxity in MCL tension so that a 2-mm tension gauge can be inserted. In mobile-bearing UKA, appropriate MCL tension is needed to prevent bearing dislocation. This difference in MCL tension may have caused the difference in the correction angle between the groups. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. PREVALENCE OF BABESIA SPP., EHRLICHIA SPP., AND TICK INFESTATIONS IN OKLAHOMA BLACK BEARS (URSUS AMERICANUS).

    Science.gov (United States)

    Skinner, Delaina; Mitcham, Jessica R; Starkey, Lindsay A; Noden, Bruce H; Fairbanks, W Sue; Little, Susan E

    2017-10-01

    American black bears (Ursus americanus) are commonly infested with ticks throughout their range, but there are few surveys for tick-borne disease agents in bears. To characterize tick infestations and determine the prevalence of current infection with Babesia spp. and past or current infection with Ehrlichia spp. in newly re-established populations of black bears in east central and southeastern Oklahoma, US, we identified adult (n=1,048) and immature (n=107) ticks recovered from bears (n=62). We evaluated serum and whole blood samples from a subset (n=49) for antibodies reactive to, and characteristic DNA fragments of, Ehrlichia spp., as well as characteristic DNA fragments of Babesia spp. Amblyomma americanum, the most common tick identified, was found on a majority (56/62; 90%) of bears and accounted for 697/1,048 (66.5%) of all ticks recovered. Other ticks included Dermacentor variabilis (338/1,048; 32.3%) from 36 bears, Amblyomma maculatum (9/1,048; 0.9%) from three bears, and Ixodes scapularis (4/1,048; 0.4%) from three bears. Antibodies reactive to Ehrlichia spp. were detected in every bear tested (49/49; 100%); maximum inverse titers to Ehrlichia chaffeensis ranged from 64-4,096 (geometric mean titer 1,525). However, PCR failed to identify active infection with E. chaffeensis, Ehrlichia ewingii, or an Ehrlichia ruminantium-like agent. Infection with Babesia spp. was detected by PCR in 3/49 (6%) bears. Together these data confirm that tick infestations and infection with tick-borne disease agents are common in bears in the southern US. The significance of these infestations and infections to the health of bears, if any, and the identity of the Ehrlichia spp. responsible for the antibody reactivity seen, warrant further evaluation.

  10. Study of stiffness and bearing capacity degradation of reinforced concrete beams under constant-amplitude fatigue.

    Science.gov (United States)

    Liu, Fangping; Zhou, Jianting; Yan, Lei

    2018-01-01

    For a reinforced concrete beam subjected to fatigue loads, the structural stiffness and bearing capacity will gradually undergo irreversible degeneration, leading to damage. Moreover, there is an inherent relationship between the stiffness and bearing capacity degradation and fatigue damage. In this study, a series of fatigue tests are performed to examine the degradation law of the stiffness and bearing capacity. The results pertaining to the stiffness show that the stiffness degradation of a reinforced concrete beam exhibits a very clear monotonic decreasing "S" curve, i.e., the stiffness of the beam decreases significantly at the start of the fatigue loading, it undergoes a linear decline phase in the middle for a long loading period, and before the failure, the bearing capacity decreases drastically again. The relationship between the residual stiffness and residual bearing capacity is determined based on the assumption that the residual stiffness and residual bearing capacity depend on the same damage state, and then, the bearing capacity degradation model of the reinforced concrete beam is established based on the fatigue stiffness. Through the established model and under the premise of the known residual stiffness degradation law, the degradation law of the bearing capacity is determined by using at least one residual bearing capacity test data, for which the parameters of the stiffness degradation function are considered as material constants. The results of the bearing capacity show that the bearing capacity degradation of the reinforced concrete beam also exhibits a very clear monotonic decreasing "S" curve, which is consistent with the stiffness degradation process and in good agreement with the experiment. In this study, the stiffness and bearing capacity degradation expressions are used to quantitatively describe their occurrence in reinforced concrete beams. In particular, the expression of the bearing capacity degradation can mitigate numerous

  11. Coupled Dynamics of a Rotor-Journal Bearing System Equipped with Thrust Bearings

    Directory of Open Access Journals (Sweden)

    Yu Lie

    1995-01-01

    Full Text Available The rotordynamic coefficients of fixed-pad thrust bearing are introduced and calculated by using the out-domain method, and a general analysis method is developed to investigate the coupled dynamics of a rotor equipped with journal and thrust bearings simultaneously. Considerations include the effects of static tilt parameters of the rotor on rotordynamic coefficients of thrust bearing and the action of thrust bearing on system dynamics. It is shown that thrust bearing changes the load distribution of journal bearings and the static deflection of the rotor and delays the instability of the system considerably in lateral shaft vibration.

  12. The dual action gas thrust bearing - A new high load bearing concept

    Science.gov (United States)

    Etsion, I.

    1976-01-01

    The principle of utilizing hydrodynamic effects in diverging films for improving load capacity in gas thrust bearings is discussed. A new concept of dual action bearing based on that principle is described and analyzed. The potential of the new bearing is demonstrated both analytically for an infinitely long slider and by numerical solution for a flat sector shaped thrust bearing. It is shown that the dual action bearing can extend substantially the range of load carrying capacity in gas lubricated thrust bearings and improve their efficiency.

  13. Construction of gas suspended bearings (radial and axial gas ball bearings)

    International Nuclear Information System (INIS)

    Kaspar, G.

    1974-10-01

    This report contains practical and theoretical results that were obtained at IPP in the section of gas suspended bearings. The two air-cushioned, air-driven revolving mirrors and an air-cushioned, air measuring coil drive were built. The latter has a double radial bearing and a single axial bearing. The axial bearing is shaped in such a way that, with slight throttling of the air feed, i.e. at low air intake pressure, a relatively high bearing load can be imposed and the bearing remains at the same time free of the so-called air hammer effect. (orig.) [de

  14. Can we determine the filament chirality by the filament footpoint location or the barb-bearing?

    Science.gov (United States)

    Hao, Qi; Guo, Yang; Fang, Cheng; Chen, Peng-Fei; Cao, Wen-Da

    2016-01-01

    We attempt to propose a method for automatically detecting the solar filament chirality and barb bearing. We first introduce the concept of an unweighted undirected graph and adopt the Dijkstra shortest path algorithm to recognize the filament spine. Then, we use the polarity inversion line (PIL) shift method for measuring the polarities on both sides of the filament, and employ the connected components labeling method to identify the barbs and calculate the angle between each barb and the spine to determine the bearing of the barbs, i.e., left or right. We test the automatic detection method with Hα filtergrams from the Big Bear Solar Observatory (BBSO) Hα archive and magnetograms observed with the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO). Four filaments are automatically detected and illustrated to show the results. The barbs in different parts of a filament may have opposite bearings. The filaments in the southern hemisphere (northern hemisphere) mainly have left-bearing (right-bearing) barbs and positive (negative) magnetic helicity, respectively. The tested results demonstrate that our method is efficient and effective in detecting the bearing of filament barbs. It is demonstrated that the conventionally believed one-to-one correspondence between filament chirality and barb bearing is not valid. The correct detection of the filament axis chirality should be done by combining both imaging morphology and magnetic field observations.

  15. Can we determine the filament chirality by the filament footpoint location or the barb-bearing?

    International Nuclear Information System (INIS)

    Hao, Qi; Guo, Yang; Fang, Cheng; Chen, Peng-Fei; Cao, Wen-Da

    2016-01-01

    We attempt to propose a method for automatically detecting the solar filament chirality and barb bearing. We first introduce the concept of an unweighted undirected graph and adopt the Dijkstra shortest path algorithm to recognize the filament spine. Then, we use the polarity inversion line (PIL) shift method for measuring the polarities on both sides of the filament, and employ the connected components labeling method to identify the barbs and calculate the angle between each barb and the spine to determine the bearing of the barbs, i.e., left or right. We test the automatic detection method with Hα filtergrams from the Big Bear Solar Observatory (BBSO) Hα archive and magnetograms observed with the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO). Four filaments are automatically detected and illustrated to show the results. The barbs in different parts of a filament may have opposite bearings. The filaments in the southern hemisphere (northern hemisphere) mainly have left-bearing (right-bearing) barbs and positive (negative) magnetic helicity, respectively. The tested results demonstrate that our method is efficient and effective in detecting the bearing of filament barbs. It is demonstrated that the conventionally believed one-to-one correspondence between filament chirality and barb bearing is not valid. The correct detection of the filament axis chirality should be done by combining both imaging morphology and magnetic field observations. (paper)

  16. Utilisation of acoustic emission technique to monitor lubrication condition in a low speed bearing

    International Nuclear Information System (INIS)

    Nordin Jamaludin; Mohd Jailani Mohd Nor

    2003-01-01

    Monitoring of lubrication condition in rolling element bearings through the use of vibration analysis is an established technique. However, this success has not mirrored at low rotational speeds. At low speeds the energy generated from the poor lubricated bearing lubrication might not show as an obvious change in signature and thus become undetectable using conventional vibration measuring equipment. This paper presents an investigation into the applicability of acoustic emission technique and analysis for detecting poorly lubricated bearing rotating at a speed of 1.12 rpm. Investigations were centered on a test-rig designed to simulate the real bearing used in the field. The variation of lubricant amount in the low-speed bearing was successfully monitored using a new developed method known as pulse injection technique (PIT). The PIT technique was based on acoustic emission method. The technique involved transmitting a Dirac pulse to the test bearing via a transmitting acoustic emission sensor while the bearing was in operation. Analysing the captured acoustic emission signatures using established statistical method could differentiate between properly and poorly lubricated bearing. (Author)

  17. Demographic characteristics and infectious diseases of a population of American black bears in Humboldt County, California.

    Science.gov (United States)

    Stephenson, Nicole; Higley, J Mark; Sajecki, Jaime L; Chomel, Bruno B; Brown, Richard N; Foley, Janet E

    2015-02-01

    American black bears (Ursus americanus) are common, widely distributed, and broad-ranging omnivorous mammals in northern California forests. Bears may be susceptible to pathogens infecting both domestic animals and humans. Monitoring bear populations, particularly in changing ecosystems, is important to understanding ecological features that could affect bear population health and influence the likelihood that bears may cause adverse impacts on humans. In all, 321 bears were captured between May, 2001, and October, 2003, and blood samples were collected and tested for multiple zoonotic and vector-borne diseases. We found a PCR prevalence of 10% for Anaplasma phagocytophilum, and a seroprevalence of 28% for Toxoplasma gondii, 26% for Borrelia burgdorferi, 26% for A. phagocytophilum, 8% for Trichinella spiralis, 8% for Francisella tularensis and 1% for Yersinia pestis. In addition, we tested bears for pathogens of domestic dogs and found a seroprevalence of 15% for canine distemper virus and 0.6% for canine parvovirus. Our findings show that black bears can become infected with pathogens that are an important public health concern, as well as pathogens that can affect both domestic animals and other wildlife species.

  18. Analysis of Space Station Centrifuge Rotor Bearing Systems: A Case Study

    Science.gov (United States)

    Poplawski, Joseph V.; Loewenthal, Stuart H.; Oswald, Fred B.; Zaretsky, Erwin V.; Morales, Wilfredo; Street, Kenneth W., Jr.

    2014-01-01

    A team of NASA bearing and lubrication experts was assembled to assess the risk for the rolling-element bearings used in the International Space Station (ISS) centrifuge rotor (CR) to seize or otherwise fail to survive for the required 10-year life. The CR was designed by the Japan Aerospace Exploration Agency and their subcontractor, NEC Toshiba Space Systems, Ltd. (NTSpace). The NASA team performed a design audit for the most critical rolling-element bearing systems and reviewed the lubricant selected. There is uncertainty regarding the ability of the Braycote 601 grease (Castrol Limited) to reliably provide the 10-year continuous life required without relubrication of the system. The fatigue life of the Rotor Shaft Assembly (RSA) spring loaded face-to-face mount at a 99-percent probability of survival (L1 life) for the ball bearing set was estimated at 700 million hours and the single ball bearing (Row 3) at 58 million hours. These lives satisfy the mission requirements for fatigue. Rolling-element seizure tests on the RSA and fluid slip joint bearings were found unlikely to stop the centrifuge, which can cause damage to the ISS structure. The spin motor encoder duplex angular-contact ball bearings have a hard preload and a large number of small balls have the highest risk of failure. These bearings were not tested for seizure even though they are less tolerant to debris or internal clearance reductions.

  19. Are organohalogen contaminants a bears (Ursus maritimus)?

    DEFF Research Database (Denmark)

    Sonne, Christian; Dietz, Rune; Leifsson, PS

    2006-01-01

    Tissues of polar bears (Ursus maritimus) from East Greenland contain the highest concentrations of organohalogen contaminants (OHCs) among subpopulations of any mammalian species in the Arctic. Negative associations also have been found between OHC concentrations and bone mineral density and liver...... histology parameters for this subpopulation of polar bears. The present study examined the OHC concentrations and adverse effects on renal tissue for 75 polar bears collected during 1999 to 2002. Specific lesions were diffuse glomerular capillary wall thickening, mesangial glomerular deposits, tubular...

  20. Low-temperature radiation-resistant material for ball-bearing retainers

    Science.gov (United States)

    Desau, P. O.; Emmons, W. F.

    1970-01-01

    Radiation resistant material, made of polyimide polymers and S-glass cloth, is used in ball bearing retainers for extreme environments. Material displays satisfactory wear resistance, lubricity, and stability. Results of comparative tests with fluorocarbon materials are given.

  1. Quality assurance during fabrication of high-damping rubber isolation bearings

    Energy Technology Data Exchange (ETDEWEB)

    Way, D.; Greaves, W.C. [Base Isolation Consultants, Inc., San Francisco, CA (United States)

    1995-12-01

    Successful implementation of a high-damping rubber (HDR) base isolation project requires the application of Quality Assurance/Quality Control (QA/QC) methodology through all phases of the bearing fabrication process. HDR base isolation bearings must be fabricated with uniform physical characteristics while being produced in large quantities. To satisfy this requirement, manufacturing processes must be controlled. Prototype tests that include dynamic testing of small samples of rubber are necessary. Stringent full scale bearing testing must be carried out prior to beginning production, during which manufacturing is strictly regulated by small rubber sample and production bearing testing. All such activities should be supervised and continuously inspected by independent and experienced QA/QC personnel.

  2. An Experimental Investigation into the Temperature Profile of a Compliant Foil Air Bearing

    National Research Council Canada - National Science Library

    Radil, Kevin

    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...

  3. Prevalence of Toxoplasma gondii infections in Pennsylvania black bears, Ursus americanus.

    Science.gov (United States)

    Briscoe, N; Humphreys, J G; Dubey, J P

    1993-10-01

    Serum samples from 665 hunter-killed black bears killed in 1989 to 1992 throughout Pennsylvania (USA) were tested for Toxoplasma gondii antibodies by the agglutination test in dilutions of 1:25, 1:50, and 1:500. Toxoplasma gondii antibodies were found in 535 of 665 (80%) bears. Considering the highest dilutions at which antibodies were detected, prevalences were 10% at 1:25, 37% at 1:50 and 33% at 1:500. No significant difference in antibody prevalence was found between males (79%) and females (80%), but a significant difference was found between juvenile (65%) and adult (83%) bears.

  4. Development of a hybrid bearing using permanent magnets and piezoelectric actuators

    International Nuclear Information System (INIS)

    Park, Jung-Ho; Ham, Young-Bog; Yun, So-Nam; Lee, Hu-Seung

    2010-01-01

    In this study, a hybrid magnetic bearing with permanent magnets and piezoelectric actuators is investigated. First, in this study, a novel concept in which piezoelectric actuators are used to compensate for low stiffness and damping resulting from the unstable characteristics of a passive magnetic bearing using only permanent magnets is proposed. Secondly, the permanent magnets are optimally arranged through an electromagnetic field analysis. Then, the driving amplifier unit and a prototype radial bearing using the proposed concept are fabricated. Finally, basic characteristics, such as the results of an impact test and a rotational runout test with constant speed are investigated and discussed, and experiments using PID control method are conducted.

  5. Relation Between the Structural Components and Nonmetallic Inclusions and the Operating Properties of Bearing Steel

    Science.gov (United States)

    Moroz, A. N.; Glotka, A. A.

    2018-01-01

    The endurance of bearing steel ShKh15SG under cyclic bending tests is studied. The relation between the cyclic bending frequency and the ultimate bending strength is determined. It is shown that the endurance calculated by the prototype method does not match the results of full-scale tests of bearings. A new method for determining the endurance of bearings from steel ShKh15SG allowing for the distribution of nonmetallic inclusions in the carbide bands and outside them is suggested.

  6. Optimal bearing gap of a multiarc radial bearing in a hydrodynamically levitated centrifugal blood pump for the reduction of hemolysis.

    Science.gov (United States)

    Kosaka, Ryo; Yasui, Kazuya; Nishida, Masahiro; Kawaguchi, Yasuo; Maruyama, Osamu; Yamane, Takashi

    2014-09-01

    We have developed a hydrodynamically levitated centrifugal pump as a bridge-to-decision device. The purpose of the present study is to determine the optimal bearing gap of a multiarc radial bearing in the developed blood pump for the reduction of hemolysis. We prepared eight pump models having bearing gaps of 20, 30, 40, 80, 90, 100, 180, and 250 μm. The driving conditions were set to a pressure head of 200 mm Hg and a flow rate of 4 L/min. First, the orbital radius of the impeller was measured for the evaluation of the impeller stability. Second, the hemolytic property was evaluated in an in vitro hemolysis test. As a result, the orbital radius was not greater than 15 μm when the bearing gap was between 20 and 100 μm. The relative normalized index of hemolysis (NIH) ratios in comparison with BPX-80 were 37.67 (gap: 20 μm), 0.95 (gap: 30 μm), 0.96 (gap: 40 μm), 0.82 (gap: 80 μm), 0.77 (gap: 90 μm), 0.92 (gap: 100 μm), 2.76 (gap: 180 μm), and 2.78 (gap: 250 μm). The hemolysis tended to increase at bearing gaps of greater than 100 μm due to impeller instability. When the bearing gap decreased from 30 to 20 μm, the relative NIH ratios increased significantly from 0.95 to 37.67 times (P pump for the reduction of hemolysis. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  7. Technical Development Path for Gas Foil Bearings

    Science.gov (United States)

    Dellacorte, Christopher

    2016-01-01

    Foil gas bearings are in widespread commercial use in air cycle machines, turbocompressors and microturbine generators and are emerging in more challenging applications such as turbochargers, auxiliary power units and propulsion gas turbines. Though not well known, foil bearing technology is well over fifty years old. Recent technological developments indicate that their full potential has yet to be realized. This paper investigates the key technological developments that have characterized foil bearing advances. It is expected that a better understanding of foil gas bearing development path will aid in future development and progress towards more advanced applications.

  8. Prediction of California Bearing Ratio from Physical Properties of Fine-Grained Soils

    OpenAIRE

    Bao Thach Nguyen; Abbas Mohajerani

    2015-01-01

    The California Bearing Ratio (CBR) has been acknowledged as an important parameter to characterize the bearing capacity of earth structures, such as earth dams, road embankments, airport runways, bridge abutments and pavements. Technically, the CBR test can be carried out in the laboratory or in the field. The CBR test is time-consuming and is infrequently performed due to the equipment needed and the fact that the field moisture content keeps changing over time. Over the...

  9. Bearing and Swelling Properties of Randomly Distributed Waste Jute Reinforced Soil

    OpenAIRE

    Ozturk, Murat; Cabalar, Ali Fırat

    2017-01-01

    In this study, waste jute, which was provided from textile companies, was investigated to define effect of waste jute on swelling and bearing behavior of the sand used. Three different water content (17, 19 and 21%) and four different waste jute addition amount at different percentages (0, 1, 2, and 3) by mass of dry soil were selected as design variables. With defined variables Swelling Ratio and California Bearing Ratio (CBR) tests were conducted. According to test results it is concluded t...

  10. Sources of mycosporine-like amino acids in planktonic Chlorella-bearing ciliates (Ciliophora)

    OpenAIRE

    SONNTAG, BETTINA; SUMMERER, MONIKA; SOMMARUGA, RUBEN

    2007-01-01

    Mycosporine-like amino acids (MAAs) are a family of secondary metabolites known to protect organisms exposed to solar UV radiation. We tested their distribution among several planktonic ciliates bearing Chlorella isolated from an oligo-mesotrophic lake in Tyrol, Austria. In order to test the origin of these compounds, the MAAs were assessed by high performance liquid chromatography in both the ciliates and their symbiotic algae. Considering all Chlorella-bearing ciliates, we found: (i) seven ...

  11. Rolling Contact Fatigue and Static Compression Deformation of UHMWPE thrust bearing in water

    Directory of Open Access Journals (Sweden)

    Inagaki Masahiro

    2017-01-01

    Full Text Available In this study, the rolling contact fatigue tests were performed in order to investigate the effect of thrust load on life of UHMWPE bearings. Furthermore, the static compression tests were performed in order to investigate the effect of static load on deformation. It was found that thrust load controls limitations of the bearings, and the deformation by the static load is not the main reason of the adhesion failure.

  12. Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage.

    Science.gov (United States)

    Hailer, Frank; Kutschera, Verena E; Hallström, Björn M; Klassert, Denise; Fain, Steven R; Leonard, Jennifer A; Arnason, Ulfur; Janke, Axel

    2012-04-20

    Recent studies have shown that the polar bear matriline (mitochondrial DNA) evolved from a brown bear lineage since the late Pleistocene, potentially indicating rapid speciation and adaption to arctic conditions. Here, we present a high-resolution data set from multiple independent loci across the nuclear genomes of a broad sample of polar, brown, and black bears. Bayesian coalescent analyses place polar bears outside the brown bear clade and date the divergence much earlier, in the middle Pleistocene, about 600 (338 to 934) thousand years ago. This provides more time for polar bear evolution and confirms previous suggestions that polar bears carry introgressed brown bear mitochondrial DNA due to past hybridization. Our results highlight that multilocus genomic analyses are crucial for an accurate understanding of evolutionary history.

  13. Treatment of alpha bearing wastes

    International Nuclear Information System (INIS)

    1988-01-01

    This report deals with the current state of the art of alpha waste treatment, which is an integral part of the overall nuclear waste management system. The International Atomic Energy Agency (IAEA) defines alpha bearing waste as 'waste containing one or more alpha emitting radionuclides, usually actinides, in quantities above acceptable limits'. The limits are established by national regulatory bodies. The limits above which wastes are considered as alpha contaminated refer to the concentrations of alpha emitters that need special consideration for occupational exposures and/or potential safety, health, or environmental impact during one or more steps from generation through disposal. Owing to the widespread use of waste segregation by source - that is, based upon the 'suspect origin' of the material - significant volumes of waste are being handled as alpha contaminated which, in fact, do not require such consideration by reason of risk or environmental concern. The quantification of de minimis concepts by national regulatory bodies could largely contribute to the safe reduction of waste volumes and associated costs. Other factors which could significantly contribute to the reduction of alpha waste arisings are an increased application of assaying and sorting, instrumentation and the use of feedback mechanisms to control or modify the processes which generate these wastes. Alpha bearing wastes are generated during fabrication and reprocessing of nuclear fuels, decommissioning of alpha contaminated facilities, and other activities. Most alpha wastes are contact handled, but a small portion may require shielding or remote handling because of high levels of neutron (n), beta (β), or gamma (γ) emissions associated with the waste material. This report describes the sources and characteristics of alpha wastes and strategies for alpha waste management. General descriptions of treatment processes for solid and liquid alpha wastes are included. 71 refs, 14 figs, 9 tabs

  14. Microstructural and Material Quality Effects on Rolling Contact Fatigue of Highly Elastic Intermetallic NiTi Ball Bearings

    Science.gov (United States)

    Dellacorte, Christopher; Howard, S. Adam; Thomas, Fransua; Stanford, Malcolm K.

    2017-01-01

    Rolling element bearings made from highly-elastic intermetallic materials (HIM)s, such as 60NiTi, are under development for applications that require superior corrosion and shock resistance. Compared to steel, intermetallics have been shown to have much lower rolling contact fatigue (RCF) stress capability in simplified 3-ball on rod (ASTM STP 771) fatigue tests. In the 3-ball tests, poor material quality and microstructural flaws negatively affect fatigue life but such relationships have not been established for full-scale 60NiTi bearings. In this paper, 3-ball-on-rod fatigue behavior of two quality grades of 60NiTi are compared to the fatigue life of full-scale 50mm bore ball bearings made from the same materials. 60NiTi RCF rods with material or microstructural flaws suffered from infant mortality failures at all tested stress levels while high quality 60NiTi rods exhibited no failures at lower stress levels. Similarly, tests of full-scale bearings made from flawed materials exhibited early surface fatigue and through crack type failures while bearings made from high quality material did not fail even in long-term tests. Though the full-scale bearing test data is yet preliminary, the results suggest that the simplified RCF test is a good qualitative predictor of bearing performance. These results provide guidance for materials development and to establish minimum quality levels required for successful bearing operation and life.

  15. Early Versus Late Weight-Bearing Protocols for Surgically Managed Posterior Wall Acetabular Fractures.

    Science.gov (United States)

    Heare, Austin; Kramer, Nicholas; Salib, Christopher; Mauffrey, Cyril

    2017-07-01

    Despite overall improved outcomes with open reduction and internal fixation of acetabular fractures, posterior wall fractures show disproportionately poor results. The effect of weight bearing on outcomes of fracture management has been investigated in many lower extremity fractures, but evidence-based recommendations in posterior wall acetabular fractures are lacking. The authors systematically reviewed the current literature to determine if a difference in outcome exists between early and late postoperative weight-bearing protocols for surgically managed posterior wall acetabular fractures. PubMed and MEDLINE were searched for posterior wall acetabular fracture studies that included weight-bearing protocols and Merle d'Aubigné functional scores. Twelve studies were identified. Each study was classified as either early or late weight bearing. Early weight bearing was defined as full, unrestricted weight bearing at or before 12 weeks postoperatively. Late weight bearing was defined as restricted weight bearing for greater than 12 weeks postoperatively. The 2 categories were then compared by functional score using a 2-tailed t test and by complication rate using chi-square analysis. Six studies (152 fractures) were placed in the early weight-bearing category. Six studies (302 fractures) were placed in the late weight-bearing category. No significant difference in Merle d'Aubigné functional scores was found between the 2 groups. No difference was found regarding heterotopic ossification, avascular necrosis, superficial infections, total infections, or osteoarthritis. This systematic review found no difference in functional outcome scores or complication rates between early and late weight-bearing protocols for surgically treated posterior wall fractures. [Orthopedics. 2017: 40(4):e652-e657.]. Copyright 2017, SLACK Incorporated.

  16. Friction and wear properties of Cu and Fe-based P/M bearing materials

    International Nuclear Information System (INIS)

    Tufekci, Kenan; Kurbanoglu, Cahit; Durak, Ertugrul; Tunay, R. Fatih

    2006-01-01

    The performances of porous bearings under different operating conditions were experimentally investigated in this study. Material groups studied are 90%Cu + 10%Sn bronze and 1%C + % balance Fe iron-based self-lubricating P/M bearings at constant (85%) density. In the experiments, the variation of the coefficient of friction and wear ratio of those two different group materials for different sliding speeds, loads, and temperatures were investigated. As a result, the variation of the friction coefficient - temperature for both constant load, and constant sliding speed, friction coefficient - average bearing pressure, PV - wear loss and temperature-wear loss curves were plotted and compared with each other for two materials, separately. The test results showed that Cu-based bearings have better friction and wear properties than Fe-based bearings

  17. A study on the ultrasonic measurement for damage evaluation of power plant bearing

    International Nuclear Information System (INIS)

    Lee, Sang Guk

    2004-01-01

    For the purpose of monitoring by ultrasonic test of the ball bearing conditions in rotating machinery, a system for their diagnosis was developed. Ultrasonic technique is used to detect abnormal conditions in the bearing system. And various data such as frequency spectrum, energy and amplitude of ultrasonic signals, and ultrasonic parameters were acquired during experiments with the simulated ball bearing system. Based on the above results and practical application for power plant, algorithms and judgement criteria for diagnosis system was established. Bearing diagnosis system is composed of four parts as follows : sensing part for ultrasonic sensor and preamplifier, signal processing part for measuring frequency spectrum, energy and amplitude, interface part for connecting ultrasonic signal to PC using A/D converter, graphic display and software part for display of bearing condition and for managing of diagnosis program

  18. Train axle bearing fault detection using a feature selection scheme based multi-scale morphological filter

    Science.gov (United States)

    Li, Yifan; Liang, Xihui; Lin, Jianhui; Chen, Yuejian; Liu, Jianxin

    2018-02-01

    This paper presents a novel signal processing scheme, feature selection based multi-scale morphological filter (MMF), for train axle bearing fault detection. In this scheme, more than 30 feature indicators of vibration signals are calculated for axle bearings with different conditions and the features which can reflect fault characteristics more effectively and representatively are selected using the max-relevance and min-redundancy principle. Then, a filtering scale selection approach for MMF based on feature selection and grey relational analysis is proposed. The feature selection based MMF method is tested on diagnosis of artificially created damages of rolling bearings of railway trains. Experimental results show that the proposed method has a superior performance in extracting fault features of defective train axle bearings. In addition, comparisons are performed with the kurtosis criterion based MMF and the spectral kurtosis criterion based MMF. The proposed feature selection based MMF method outperforms these two methods in detection of train axle bearing faults.

  19. Influence of the thrust bearing on the natural frequencies of a 72-MW hydropower rotor

    Science.gov (United States)

    Cupillard, S.; Aidanpää, J.-O.

    2016-11-01

    The thrust bearing is an essential element of a hydropower machine. Not only does it carry the total axial load but it also introduces stiffness and damping properties in the system. The focus of this study is on the influence of the thrust bearing on the lateral vibrations of the shaft of a 72-MW propeller turbine. The thrust bearing has a non-conventional design with a large radius and two rows of thrust pads. A numerical model is developed to estimate natural frequencies. Numerical results are analyzed and related to experimental measurements of a runaway test. The results show the need to include the thrust bearing in the model. In fact, the vibration modes are substantially increased towards higher frequencies with the added properties from the thrust bearing. The second mode of vibration has been identified in the experimental measurements. Its frequency and mode shape compare well with numerical results.

  20. The Bearing Strength and Fracture Behavior of Bolted Connections in Two Aluminum Alloys

    Science.gov (United States)

    Tinl, N.; Menzemer, C. C.; Manigandan, K.; Srivatsan, T. S.

    2013-11-01

    In this paper, the bearing capacity, taken as a combination of strength, elongation, and failure by fracture characteristics of bolt holes in two aluminum alloys, 5052-H32 and 6061-T6, that were deformed in uniaxial tension is presented and discussed. The specific role played by bolt hole confinement on the bearing capacity of each aluminum alloy is highlighted. An increase in the bearing ratio caused plastic deformation around the holes to gradually increase. For both the chosen aluminum alloys the average bearing ratio at the time of failure of the test sample was found to vary with end distance. The experimentally determined strength was observably larger than the calculated bearing strength obtained using guaranteed minimum mechanical properties and recommended mathematical relationships. The nature of final fracture of each aluminum alloy is carefully examined and the intrinsic features present on the fracture surface are rationalized in concurrence with macroscopic mechanical response.

  1. Effects of roads on habitat quality for bears in the southern Appalachians: A long-term study

    Science.gov (United States)

    Reynolds-Hogland, M. J.; Mitchell, M.S.

    2007-01-01

    We tested the hypothesis that gravel roads, not paved roads, had the largest negative effect on habitat quality for a population of American black bears (Ursus americanus) that lived in a protected area, where vehicle collision was a relatively minimal source of mortality. We also evaluated whether road use by bears differed by sex or age and whether annual variation in hard mast productivity affected the way bears used areas near roads. In addition, we tested previous findings regarding the spatial extent to which roads affected bear behavior negatively. Using summer and fall home ranges for 118 black bears living in the Pisgah Bear Sanctuary in western North Carolina during 1981-2001, we estimated both home-range-scale (2nd-order) and within-home-range-scale (3rd-order) selection for areas within 250, 500, 800, and 1,600 m of paved and gravel roads. All bears avoided areas near gravel roads more than they avoided areas near paved roads during summer and fall for 2nd-order selection and during summer for 3rd-order selection. During fall, only adult females avoided areas near gravel roads more than they avoided areas near paved roads for 3rd-order selection. We found a positive relationship between use of roads by adults and annual variability in hard mast productivity. Overall, bears avoided areas within 800 m of gravel roads. Future research should determine whether avoidance of gravel roads by bears affects bear survival. ?? 2007 American Society of Mammalogists.

  2. The effect of loading rate on pile bearing capacity of saturated sand

    NARCIS (Netherlands)

    Archeewa, E.

    2005-01-01

    Pile load tests are commonly used by engineers to determine its bearing capacity. At present, there are three methods of pile load tests: the static, the dynamic and the quasi-static test. The static pile load test is done by applying an axial load on the pile with a long duration. The dynamic and

  3. Behavioural Profiles of Brown and Sloth Bears in Captivity

    Science.gov (United States)

    Quintavalle Pastorino, Giovanni; Christodoulides, Yiannis; Curone, Giulio; Pearce-Kelly, Paul; Faustini, Massimo; Albertini, Mariangela; Preziosi, Richard; Mazzola, Silvia Michela

    2017-01-01

    Simple Summary Animal personality research is a growing field, since understanding animal personalities has notable implications in ecology and the evolution of animal behaviours. In the current study, we tested different methods described in the literature to obtain robust individual behavioural profiles. Data collected through behavioral observations were categorised into activity budgets, space usage, and social interactions for each individual. In addition, behavioural profile questionnaires were completed by the three zoo keepers who had regular interactions with the bears. The questionnaires included 22 adjectives, which were rated on a scale of 1–12 depending on how well they described each individual bear. The mean ratings of the keepers were used to create the behavioural profiles by adding the adjectives to the appropriate domains, according to the NEO Five Factor Inventory of personality model (NEO-FFI). The data gathered was used to produce behavioural profiles for all animals, in order to clarify the personality characteristics of each subject. Testing and improving existing methodologies to determine animal personality is important for providing optimal welfare and management of captive animals, since it can help to develop more effective management regimes in zoos by remodelling husbandry according to each animal’s personality type. Abstract Three brown bear (Ursus arctos arctos) individuals and two sloth bear (Melursus ursinus inornatus) individuals were observed in captivity to produce behavioural profiles for each individual. Data collected through behavioural observations were used to produce activity budgets, and to identify space usage and certain aspects of social behavior. Behaviour monitoring allowed the researchers to evaluate the welfare of the animals by identifying the occurrence of stereotypic behaviours, which are sometimes associated with stress. Behavioural profiles were created using data obtained through behavioural

  4. Evaluation of the Thermal Effects in Tilting Pad Bearing

    Directory of Open Access Journals (Sweden)

    G. B. Daniel

    2013-01-01

    Full Text Available The analysis of thermal effects is of expressive importance in the context of rotordynamics to evaluate the behavior of hydrodynamic bearings because these effects can influence their dynamic characteristics under specific operational conditions. For this reason, a thermohydrodynamic model is developed in this work, in which the pressure distribution in the oil film and the temperature distribution are calculated together. From the pressure distribution, the velocity distribution field is determined, as well as the viscous dissipation, and consequently, the temperature distribution. The finite volume method is applied to solve the Reynolds equation and the energy equation in the thermohydrodynamic model (THD. The results show that the temperature is higher as the rotational speed increases due to the shear rate of the oil film. The maximum temperature in the bearing occurs in the overloaded pad, near the outlet boundary. The experimental tests were performed in a tilting pad journal bearing operating in a steam turbine to validate the model. The comparison between the experimental and numerical results provides a good correlation. The thermohydrodynamic lubrication developed in this assignment is promising to consistently evaluate the behavior of the tilting pad journal bearing operating in relatively high rotational speeds.

  5. Detection of failures of axle-bearings of railway vehicles

    Directory of Open Access Journals (Sweden)

    Bižić Milan B.

    2016-01-01

    Full Text Available The failure of axle-bearing is one of the most common causes of derailments of railway vehicles which are usually accompanied by huge material damage and human casualties. Modern railways are working intensively on the development and implementation of appropriate systems for early detection of axlebearing malfunctions, which are typically manifested by increasing of its temperature. The most common approach is based on the use of wayside systems or checkpoints located in certain places along the track. There is also an innovative approach that involves using the system for continuous measuring and online monitoring of axle-boxes temperature. The main aim is to provide early detection of malfunctions of the axle-bearing and prevention of the potential derailment. This paper analyses the existing solutions for the detection of axle-bearings malfunctions with special emphasis on the working principle and the main advantages and disadvantages. The paper presents the basics of the one newly developed wireless measuring system for on-line monitoring of axle-boxes temperature. The measuring system was tested in real conditions and can be successfully applied to the commercial railway vehicles. The main conclusion is that systems for on-line monitoring of axle-bearings temperatures are far more efficient than wayside systems. Obtained results may be important for those who deal with these and similar problems, problems of development, exploitation and maintenance of railway vehicles, strategies, regulations, etc.

  6. Evaluation of bearing capacity and settlement of foundations

    Directory of Open Access Journals (Sweden)

    Bunyamin Anigilaje SALAHUDEEN

    2016-12-01

    Full Text Available The standard penetration test (SPT results (SPT N-values used in this study were corrected to the standard average energy of 60% (N60 before using them to correlate soil properties and evaluate foundation settlement characteristics and bearing capacity in the North Central zone of Nigeria. Based on the corrected N-values, some geotechnical design parameters including the allowable bearing pressure and elastic settlement of foundations were predicted at varying applied foundation pressures of 50, 100, 200, 300 and 500 kN/m2 using conventional analytical models and numerical modelling. The numerical analysis results using Plaxis 2D, a finite element code, shows that Meyerhof’s and Peck’s et al. analytical/empirical methods of estimating the allowable bearing pressure of shallow foundations provide acceptable results. Results obtained show that an average bearing capacity value of 150 – 350 kN/m2 can be used for shallow foundations at embedment depth of 0.6 to 3.6 m in the North Central zone. Based on recommendation of Eurocode 7 which allows a maximum total settlement of 25 mm for serviceability limit state, it is recommended that raft or deep foundations to be considered for applied foundation pressures exceeding 300 kN/m2 in the North-Central zone to avoid excessive settlement.

  7. Serosurvey of selected zoonotic agents in polar bears (Ursus maritimus)

    Science.gov (United States)

    Rah, H.; Chomel, B.B.; Follmann, E.H.; Kasten, R.W.; Hew, C.H.; Farver, T.B.; Garner, G.W.; Amstrup, Steven C.

    2005-01-01

    Between 1982 and 1999 blood samples were collected from 500 polar bears (Ursus maritimus) captured in the Beaufort and Chukchi seas, to determine the seroprevalence of Brucella species, Toxoplasma gondii, and Trichinella species infections. The bears were classified into four age groups, cubs, yearlings, subadults and adults. Brucella and Toxoplasma antibodies were detected by agglutination (a buffered acidified card antigen and rapid automated presumptive test for brucellosis and a commercial latex agglutination test for toxoplasmosis); an ELISA was used to detect Thichinella antibodies. The overall seroprevalence of Brucella species was 5 per cent, and subadults and yearlings were 2.62 times (95 per cent confidence interval 1-02 to 6-82) more likely to be seropositive for Brucella species than adults and their cubs. The antibody prevalence for Toxoplasma gondii was 6 per cent, and for Trichinella species 55.6 per cent. The prevalence of antibodies to Trichinella species increased with age (P<0.001).

  8. Investigation of hydrostatic bearings lubricated with nitrogen tetroxide

    International Nuclear Information System (INIS)

    Greben'kov, Zh.A.; Ivanov, A.A.; Krevsun, Eh.P.

    1977-01-01

    Some types of hydrostatic bearings lubricated by nitrogen tetroxide have been investigated on a special test rig. The experiments have shown that eight-celled hydrostatic bearings with the tee-form of cells and changeable jets have the largest static supporting power, the supporting power coefficient and hardness. In this case the optimum characteristics can be easily ensured for every gap in HSB by changing the jets. By inserting in one HSB various jets, a sharp decrease of the flow rate can be also obtained, besides high supporting power and hardness. HSB without cells have a lower static supporting power and hardness but their design is more simple and the dynamic component of their supporting power and hardness is higher compared to the light-celled HSB. The experiments also have shown that among the HSB tested the eight-celled HSB appear to be the most stable

  9. A "clearcut" case? Brown bear selection of coarse woody debris and carpenter ants on clearcuts.

    Science.gov (United States)

    Frank, Shane C; Steyaert, Sam M J G; Swenson, Jon E; Storch, Ilse; Kindberg, Jonas; Barck, Hanna; Zedrosser, Andreas

    2015-07-15

    Forest management alters habitat characteristics, resulting in various effects among and within species. It is crucial to understand how habitat alteration through forest management (e.g. clearcutting) affects animal populations, particularly with unknown future conditions (e.g. climate change). In Sweden, brown bears ( Ursus arctos ) forage on carpenter ants ( Camponotus herculeanus ) during summer, and may select for this food source within clearcuts. To assess carpenter ant occurrence and brown bear selection of carpenter ants, we sampled 6999 coarse woody debris (CWD) items within 1019 plots, of which 902 were within clearcuts (forests ⩽30 years of age) and 117 plots outside clearcuts (forests >30 years of age). We related various CWD and site characteristics to the presence or absence of carpenter ant galleries (nests) and bear foraging sign at three spatial scales: the CWD, plot, and clearcut scale. We tested whether both absolute and relative counts (the latter controlling for the number of CWD items) of galleries and bear sign in plots were higher inside or outside clearcuts. Absolute counts were higher inside than outside clearcuts for galleries (mean counts; inside: 1.8, outside: 0.8). CWD was also higher inside (mean: 6.8) than outside clearcuts (mean: 4.0). However, even after controlling for more CWD inside clearcuts, relative counts were higher inside than outside clearcuts for both galleries (mean counts; inside: 0.3, outside: 0.2) and bear sign (mean counts; inside: 0.03, outside: 0.01). Variables at the CWD scale best explained gallery and bear sign presence than variables at the plot or clearcut level, but bear selection was influenced by clearcut age. CWD circumference was important for both carpenter ant and bear sign presence. CWD hardness was most important for carpenter ant selection. However, the most important predictor for bear sign was the presence or absence of carpenter ant galleries. Bears had a high foraging "success" rate (⩾88

  10. Shaft Center Orbit in Dynamically Loaded Bearings

    DEFF Research Database (Denmark)

    Klit, Peder

    2005-01-01

    The aim of this work is to demonstrate how to utilize the bearings damping coe±cients to estimate the orbit for a dynamically loaded journal bearing. The classical method for this analysis was developed by Booker in 1965 [1]and described further in 1972 [2]. Several authors have re¯ned this metho...

  11. INVESTIGATION OF ANGULAR BALL BEARING WEAR

    Directory of Open Access Journals (Sweden)

    A. L. Savchenko

    2006-01-01

    Full Text Available Wearing process of balls in an angular ball bearing has been investigated in the paper. Force affecting a separator from the side of balls is determined theoretically. Wear rate may be calculated with a formula for abrasive wear while substituting numerical parameter values of the investigated ball bearing for formula symbols.

  12. On the dynamics of ball bearings

    NARCIS (Netherlands)

    Wensing, J.A.

    1998-01-01

    This investigation on the dynamic behaviour of ball bearings was motivated by the demand for silent bearings in noise-sensitive applications, especially in the household appliance and automotive industry. The present investigations are intended to provide a clear understanding of the role of the

  13. Hydrodynamic Lubrication Analysis Of Slider Bearings Lubricated ...

    African Journals Online (AJOL)

    Hydrodynamic Lubrication Analysis Of Slider Bearings Lubricated With Micropolar Fluids. ... In this paper, a theoretical study of the effect of micropolar lubricants on the performance characteristics of wide inclined slider bearings is presented. The finite element method and Gauss Seidel iterative procedure have been used ...

  14. 33 CFR 117.543 - Bear Creek.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bear Creek. 117.543 Section 117.543 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Maryland § 117.543 Bear Creek. (a) The draws of the Baltimore...

  15. Protecting a Ball-Bearing-Deflection Monitor

    Science.gov (United States)

    Kuhr, George A.

    1987-01-01

    Deflectometer probe monitors deflection of ball-bearing race in liquid oxygen with aid of small window or diaphragm. Diaphragm or window isolates optical deflectometer from liquid oxygen or other fluid in ball bearing. At high pressures, diaphragm integral part of housing preferable to window, since there would be no leakage.

  16. Rotor Vibration Reduction via Active Hybrid Bearings

    DEFF Research Database (Denmark)

    Nicoletti, Rodrigo; Santos, Ilmar

    2002-01-01

    orifices machined in the bearing pads, one can alter the machine dynamic characteristics, thus enhancing its operational range. A mathematical model of the rotor-bearing system, as well as of the hydraulic system, is presented. Numerical results of the system frequency response show good agreement...

  17. Can polar bear hairs absorb environmental energy?

    OpenAIRE

    He Ji-Huan; Wang Qing-Li; Sun Jie

    2011-01-01

    A polar bear (Ursus maritimus) has superior ability to survive in harsh Arctic regions, why does the animal have such an excellent thermal protection? The present paper finds that the unique labyrinth cavity structure of the polar bear hair plays an important role. The hair can not only prevent body temperature loss but can also absorb energy from the environment.

  18. Can polar bear hairs absorb environmental energy?

    Directory of Open Access Journals (Sweden)

    He Ji-Huan

    2011-01-01

    Full Text Available A polar bear (Ursus maritimus has superior ability to survive in harsh Arctic regions, why does the animal have such an excellent thermal protection? The present paper finds that the unique labyrinth cavity structure of the polar bear hair plays an important role. The hair can not only prevent body temperature loss but can also absorb energy from the environment.

  19. TEMPERATURE DIAGNOSTICS OF GAS TURBINE ENGINE BEARINGS

    Directory of Open Access Journals (Sweden)

    R. V. Birukov

    2014-01-01

    Full Text Available The objective of the current research was to develop methodology for diagnosing industrial gas turbine engine bearings using the standard performance parameters. This paper presents mathematical thermal model of combined thrust and radial bearing and provides the model application examples for diagnostics.

  20. Health Assessment of Cooling Fan Bearings Using Wavelet-Based Filtering

    Directory of Open Access Journals (Sweden)

    Qiang Miao

    2012-12-01

    Full Text Available As commonly used forced convection air cooling devices in electronics, cooling fans are crucial for guaranteeing the reliability of electronic systems. In a cooling fan assembly, fan bearing failure is a major failure mode that causes excessive vibration, noise, reduction in rotation speed, locked rotor, failure to start, and other problems; therefore, it is necessary to conduct research on the health assessment of cooling fan bearings. This paper presents a vibration-based fan bearing health evaluation method using comblet filtering and exponentially weighted moving average. A new health condition indicator (HCI for fan bearing degradation assessment is proposed. In order to collect the vibration data for validation of the proposed method, a cooling fan accelerated life test was conducted to simulate the lubricant starvation of fan bearings. A comparison between the proposed method and methods in previous studies (i.e., root mean square, kurtosis, and fault growth parameter was carried out to assess the performance of the HCI. The analysis results suggest that the HCI can identify incipient fan bearing failures and describe the bearing degradation process. Overall, the work presented in this paper provides a promising method for fan bearing health evaluation and prognosis.

  1. A superlinear iteration method for calculation of finite length journal bearing's static equilibrium position

    Science.gov (United States)

    Zhou, Wenjie; Wei, Xuesong; Wang, Leqin; Wu, Guangkuan

    2017-05-01

    Solving the static equilibrium position is one of the most important parts of dynamic coefficients calculation and further coupled calculation of rotor system. The main contribution of this study is testing the superlinear iteration convergence method-twofold secant method, for the determination of the static equilibrium position of journal bearing with finite length. Essentially, the Reynolds equation for stable motion is solved by the finite difference method and the inner pressure is obtained by the successive over-relaxation iterative method reinforced by the compound Simpson quadrature formula. The accuracy and efficiency of the twofold secant method are higher in comparison with the secant method and dichotomy. The total number of iterative steps required for the twofold secant method are about one-third of the secant method and less than one-eighth of dichotomy for the same equilibrium position. The calculations for equilibrium position and pressure distribution for different bearing length, clearance and rotating speed were done. In the results, the eccentricity presents linear inverse proportional relationship to the attitude angle. The influence of the bearing length, clearance and bearing radius on the load-carrying capacity was also investigated. The results illustrate that larger bearing length, larger radius and smaller clearance are good for the load-carrying capacity of journal bearing. The application of the twofold secant method can greatly reduce the computational time for calculation of the dynamic coefficients and dynamic characteristics of rotor-bearing system with a journal bearing of finite length.

  2. Fault diagnosis of active magnetic bearings based on Gaussian GLRT detector

    DEFF Research Database (Denmark)

    Nagel, Leon; Galeazzi, Roberto; Voigt, Andreas Jauernik

    2016-01-01

    Active magnetic bearings are progressively replacing conventional bearings in many industrial applications, particularly in the energy sector. Magnetic bearings have many advantages such as contactless support and clean operation; however their use also poses some challenges connected to their in......Active magnetic bearings are progressively replacing conventional bearings in many industrial applications, particularly in the energy sector. Magnetic bearings have many advantages such as contactless support and clean operation; however their use also poses some challenges connected...... of the control system. A structural model of the bearing-rotor system is presented and used to perform a detectability and isolability analysis of faults in the magnetic actuator. Structural detectability and group-wise isolability is concluded for single and multiple faults in the actuators. A Gaussian...... generalized likelihood ratio test is proposed for detecting faults striking the electromagnet. The detector is capable of detecting and isolating the occurrence of faults in e.g. the windings of bearing by tracking changes in the mean value of a Gaussian distribution. The statistical distribution...

  3. A superlinear iteration method for calculation of finite length journal bearing's static equilibrium position.

    Science.gov (United States)

    Zhou, Wenjie; Wei, Xuesong; Wang, Leqin; Wu, Guangkuan

    2017-05-01

    Solving the static equilibrium position is one of the most important parts of dynamic coefficients calculation and further coupled calculation of rotor system. The main contribution of this study is testing the superlinear iteration convergence method-twofold secant method, for the determination of the static equilibrium position of journal bearing with finite length. Essentially, the Reynolds equation for stable motion is solved by the finite difference method and the inner pressure is obtained by the successive over-relaxation iterative method reinforced by the compound Simpson quadrature formula. The accuracy and efficiency of the twofold secant method are higher in comparison with the secant method and dichotomy. The total number of iterative steps required for the twofold secant method are about one-third of the secant method and less than one-eighth of dichotomy for the same equilibrium position. The calculations for equilibrium position and pressure distribution for different bearing length, clearance and rotating speed were done. In the results, the eccentricity presents linear inverse proportional relationship to the attitude angle. The influence of the bearing length, clearance and bearing radius on the load-carrying capacity was also investigated. The results illustrate that larger bearing length, larger radius and smaller clearance are good for the load-carrying capacity of journal bearing. The application of the twofold secant method can greatly reduce the computational time for calculation of the dynamic coefficients and dynamic characteristics of rotor-bearing system with a journal bearing of finite length.

  4. Health Assessment of Cooling Fan Bearings Using Wavelet-Based Filtering

    Science.gov (United States)

    Miao, Qiang; Tang, Chao; Liang, Wei; Pecht, Michael

    2013-01-01

    As commonly used forced convection air cooling devices in electronics, cooling fans are crucial for guaranteeing the reliability of electronic systems. In a cooling fan assembly, fan bearing failure is a major failure mode that causes excessive vibration, noise, reduction in rotation speed, locked rotor, failure to start, and other problems; therefore, it is necessary to conduct research on the health assessment of cooling fan bearings. This paper presents a vibration-based fan bearing health evaluation method using comblet filtering and exponentially weighted moving average. A new health condition indicator (HCI) for fan bearing degradation assessment is proposed. In order to collect the vibration data for validation of the proposed method, a cooling fan accelerated life test was conducted to simulate the lubricant starvation of fan bearings. A comparison between the proposed method and methods in previous studies (i.e., root mean square, kurtosis, and fault growth parameter) was carried out to assess the performance of the HCI. The analysis results suggest that the HCI can identify incipient fan bearing failures and describe the bearing degradation process. Overall, the work presented in this paper provides a promising method for fan bearing health evaluation and prognosis. PMID:23262486

  5. 60NiTi Intermetallic Material Evaluation for Lightweight and Corrosion Resistant Spherical Sliding Bearings for Aerospace Applications, Report on NASA-Kamatics SAA3-1288

    Science.gov (United States)

    Dellacorte, Christopher; Jefferson, Michael

    2015-01-01

    Under NASA Space Act Agreement (SAA3-1288), NASA Glenn Research Center and the Kamatics subsidiary of the Kaman Corporation conducted the experimental evaluation of spherical sliding bearings made with 60NiTi inner races. The goal of the project was to assess the feasibility of manufacturing lightweight, corrosion resistant bearings utilizing 60NiTi for aerospace and industrial applications. NASA produced the bearings in collaboration with Abbott Ball Corporation and Kamatics fabricated bearing assemblies utilizing their standard reinforced polymer liner material. The assembled bearings were tested in oscillatory motion at a load of 4.54 kN (10,000 lb), according to the requirements of the plain bearing specification SAE AS81820. Several test bearings were exposed to hydraulic fluid or aircraft deicing fluid prior to and during testing. The results show that the 60NiTi bearings exhibit tribological performance comparable to conventional stainless steel (440C) bearings. Further, exposure of 60NiTi bearings to the contaminant fluids had no apparent performance effect. It is concluded that 60NiTi is a feasible bearing material for aerospace and industrial spherical bearing applications.

  6. Transient response of two lobe aerodynamic journal bearing

    Directory of Open Access Journals (Sweden)

    Saurabh Kumar Yadav

    2018-03-01

    Full Text Available The dynamic behavior of a rotor-dynamic system is greatly affected by the performance of aerodynamic bearing and the performance of bearing is characterized by the stiffness and damping coefficients. In the present work, stiffness and damping coefficients of bearing are computed and the performance of the bearing is greatly changed with the change in bearing air film profile. The effect of lobe offset factors on the transient performance of aerodynamic bearing is presented. Bifurcation and Poincare diagrams of two lobe journal bearing have been presented for different offset factors. A bearing designer can judge the bearing performance based on bifurcation diagrams.

  7. Condition monitoring of thrust ball bearings using continuous AE

    Czech Academy of Sciences Publication Activity Database

    Chlada, Milan; Nohal, L.; Převorovský, Zdeněk

    2016-01-01

    Roč. 26, č. 2 (2016), A14-A14 ISSN 1213-3825. [Europen Conference on Acoustic Emission Testing /32./. 07.09.2016-09.09.2016, Praha] Grant - others:NETME Centre Plus - národní program udržitelnosti(CZ) LO1202 Institutional support: RVO:61388998 Keywords : continuous acoustic emission * rolling contact fatigue * thrust ball bearing * histogram of counting periods * wavelet analysis Subject RIV: BI - Acoustics

  8. Treatment alternatives for non-fuel-bearing hardware

    Energy Technology Data Exchange (ETDEWEB)

    Ross, W.A.; Clark, L.L.; Oma, K.H.

    1987-01-01

    This evaluation compared four alternatives for the treatment or processing of non-fuel bearing hardware (NFBH) to reduce its volume and prepare it for disposal. These treatment alternatives are: shredding; shredding and low pressure compaction; shredding and supercompaction; and melting. These alternatives are compared on the basis of system costs, waste form characteristics, and process considerations. The study recommends that melting and supercompaction alternatives be further considered and that additional testing be conducted for these two alternatives.

  9. The dynamic state monitoring of bearings system

    Directory of Open Access Journals (Sweden)

    Marek Krynke

    2015-03-01

    Full Text Available The article discusses the methods of dynamic state monitoring of bearings system. A vibration signal contains important technical information about the machine condition and is currently the most frequently used in diagnostic bearings systems. One of the main ad-vantages of machine condition monitoring is identifying the cause of failure of the bearings and taking preventative measures, otherwise the operation of such a machine will lead to frequent replacement of the bearings. Monitoring changes in the course of the operation of machin-ery repair strategies allows keeping the conditioned state of dynamic failure conditioned preventive repairs and repairs after-failure time. In addition, the paper also presents the fundamental causes of bearing failure and identifies mechanisms related to the creation of any type of damage.

  10. Development of gadolinia bearing fuel for PWR

    International Nuclear Information System (INIS)

    Seki, Kazuichiro

    1986-01-01

    In the PWR power plants in Japan, the long-period operation cycle was extended legally to a maximum of 13 months from the conventional about 9 months in fiscal 1980. With this move, as a new type of fuel with burnable-poison-rod function, the development was started of gadolinia-bearing (gadolinium oxide) fuel, gadolinia being contained in the fuel pellets. The basic technology studies were completed in fiscal 1984. Actual irradiation of the fuel in Unit 2 of the Oi Power Station was then started in July 1984, demonstrating validity of the design. Meanwhile, the rapid power-up fest and the fuel center temperature measurement are conducted in an overseas reactor from fiscal 1983. The following are described: functions of the burnable absorber, the need for gadolinia-bearing fuel, experiences with gadolinia-bearing fuel, problems in the design and production of gadolinia-bearing fuel, the development of gadolinia-bearing fuel. (Mori, K.)

  11. Geology and geomorphology of Bear Lake Valley and upper Bear River, Utah and Idaho

    Science.gov (United States)

    Reheis, M.C.; Laabs, B.J.C.; Kaufman, D.S.

    2009-01-01

    Bear Lake, on the Idaho-Utah border, lies in a fault-bounded valley through which the Bear River flows en route to the Great Salt Lake. Surficial deposits in the Bear Lake drainage basin provide a geologic context for interpretation of cores from Bear Lake deposits. In addition to groundwater discharge, Bear Lake received water and sediment from its own small drainage basin and sometimes from the Bear River and its glaciated headwaters. The lake basin interacts with the river in complex ways that are modulated by climatically induced lake-level changes, by the distribution of active Quaternary faults, and by the migration of the river across its fluvial fan north of the present lake. The upper Bear River flows northward for ???150 km from its headwaters in the northwestern Uinta Mountains, generally following the strike of regional Laramide and late Cenozoic structures. These structures likely also control the flow paths of groundwater that feeds Bear Lake, and groundwater-fed streams are the largest source of water when the lake is isolated from the Bear River. The present configuration of the Bear River with respect to Bear Lake Valley may not have been established until the late Pliocene. The absence of Uinta Range-derived quartzites in fluvial gravel on the crest of the Bear Lake Plateau east of Bear Lake suggests that the present headwaters were not part of the drainage basin in the late Tertiary. Newly mapped glacial deposits in the Bear River Range west of Bear Lake indicate several advances of valley glaciers that were probably coeval with glaciations in the Uinta Mountains. Much of the meltwater from these glaciers may have reached Bear Lake via groundwater pathways through infiltration in the karst terrain of the Bear River Range. At times during the Pleistocene, the Bear River flowed into Bear Lake and water level rose to the valley threshold at Nounan narrows. This threshold has been modified by aggradation, downcutting, and tectonics. Maximum lake

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

    Science.gov (United States)

    Dimofte, Florin

    1995-01-01

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

  13. Cement-base bearing pads mortar for connections in the precast concrete: study of surface roughness

    Directory of Open Access Journals (Sweden)

    M. K. El Debs

    Full Text Available Bearing pads are used in precast concrete connections to avoid concentrated stresses in the contact area between the precast elements. In the present research, the bearing pads are Portland cement mortar with styrene-butadiene latex (SB, lightweight aggregate (expanded vermiculite-term and short fibers (polypropylene, glass and PVA, in order to obtain a material with low modulus of elasticity and high tenacity, compared with normal Portland cement mortar. The objective of this paper is to analyze the influence of surface roughness on the pads and test other types of polypropylene fibers. Tests were carried out to characterize the composite and test on bearing pads. Characterization tests show compressive strength of 41MPa and modulus of elasticity of 12.8GPa. The bearing pads tests present 30% reduction of stiffness in relation to a reference mortar. The bearing pads with roughness on both sides present a reduction up to 30% in stiffness and an increase in accumulated deformation of more than 120%, regarding bearing pads with both sides smooth.

  14. 49 CFR 230.102 - Tender plain bearing journal boxes.

    Science.gov (United States)

    2010-10-01

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

  15. 24 CFR 3285.202 - Soil classifications and bearing capacity.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Soil classifications and bearing... Soil classifications and bearing capacity. The soil classification and bearing capacity of the soil... bearing capacity must be determined by one or more of the following methods, unless the soil bearing...

  16. The impact of adding weight-bearing exercise versus nonweight bearing programs to the medical treatment of elderly patients with osteoporosis

    Directory of Open Access Journals (Sweden)

    Alsayed A Shanb

    2014-01-01

    Full Text Available Background: Osteoporosis is a major public health problem affecting the elderly population, particularly women. The objective of the study was to evaluate the effects of adding weight-bearing exercise as opposed to nonweight-bearing programs to the medical treatment of bone mineral density (BMD and health-related quality of life (HRQoL of elderly patients with osteoporosis. Materials and Methods: Participating in the study were 40 elderly osteoporotic patients (27 females and 13 males, with ages ranging from 60 to 67 years, who were receiving medical treatment for osteoporosis. They were assigned randomly into two groups: Group-I: Twenty patients practiced weight-bearing exercises. Group-II: Twenty patients did nonweight-bearing exercises. All patients trained for 45-60 min/session, two sessions/week for 6 months. BMD of the lumbar spine, right neck of femur, and right distal radial head of all patients were measured by dual-energy X-ray absorptiometry before and after both treatment programs. In addition, the QoL was measured by means of the HRQoL "ECOS-16" questionnaire. Results: T-tests proved that mean values of BMD of the lumbar spine, right neck of femur and right distal radial head were significantly increased in both groups with greater improvement in the weight-bearing group. The QoL was significantly improved in both groups, but the difference between them was not significant. Conclusion: Addition of weight-bearing exercise program to medical treatment increases BMD more than nonweight-bearing exercise in elderly subjects with osteoporosis. Furthermore, both weight-bearing and nonweight-bearing exercise programs significantly improved the QoL of patients with osteoporosis.

  17. Toward a 3D dynamic model of a faulty duplex ball bearing

    Science.gov (United States)

    Kogan, Gideon; Klein, Renata; Kushnirsky, Alex; Bortman, Jacob

    2015-03-01

    Bearings are vital components for safe and proper operation of machinery. Increasing efficiency of bearing diagnostics usually requires training of health and usage monitoring systems via expensive and time-consuming ground calibration tests. The main goal of this research, therefore, is to improve bearing dynamics modeling tools in order to reduce the time and budget needed to implement the health and usage monitoring approach. The proposed three-dimensional ball bearing dynamic model is based on the classic dynamic and kinematic equations. Interactions between the bodies are simulated using non-linear springs combined with dampers described by Hertz-type contact relation. The force friction is simulated using the hyperbolic-tangent function. The model allows simulation of a wide range of mechanical faults. It is validated by comparison to known bearing behavior and to experimental results. The model results are verified by demonstrating numerical convergence. The model results for the two cases of single and duplex angular ball bearings with axial deformation in the outer ring are presented. The qualitative investigation provides insight into bearing dynamics, the sensitivity study generalizes the qualitative findings for similar cases, and the comparison to the test results validates model reliability. The article demonstrates the variety of the cases that the 3D bearing model can simulate and the findings to which it may lead. The research allowed the identification of new patterns generated by single and duplex bearings with axially deformed outer race. It also enlightened the difference between single and duplex bearing manifestation. In the current research the dynamic model enabled better understanding of the physical behavior of the faulted bearings. Therefore, it is expected that the modeling approach has the potential to simplify and improve the development process of diagnostic algorithms. • A deformed outer race of a single axially loaded bearing is

  18. Genomic evidence of widespread admixture from polar bears into brown bears during the last ice age.

    Science.gov (United States)

    Cahill, James A; Heintzman, Peter D; Harris, Kelley; Teasdale, Matthew D; Kapp, Joshua; Soares, André E Rodrigues; Stirling, Ian; Bradley, Daniel; Edwards, Ceiridwen J; Graim, Kiley; Kisleika, Aliaksandr A; Malev, Alexander V; Monaghan, Nigel; Green, Richard E; Shapiro, Beth

    2018-02-20

    Recent genomic analyses have provided substantial evidence for past periods of gene flow from polar bears (Ursus maritimus) into Alaskan brown bears (Ursus arctos), with some analyses suggesting a link between climate change and genomic introgression. However, because it has mainly been possible to sample bears from the present day, the timing, frequency, and evolutionary significance of this admixture remains unknown. Here, we analyze genomic DNA from three additional and geographically distinct brown bear populations, including two that lived temporally close to the peak of the last ice age. We find evidence of admixture in all three populations, suggesting that admixture between these species has been common in their recent evolutionary history. In addition, analyses of ten fossil bears from the now-extinct Irish population indicate that admixture peaked during the last ice age, when brown bear and polar bear ranges overlapped. Following this peak, the proportion of polar bear ancestry in Irish brown bears declined rapidly until their extinction. Our results support a model in which ice age climate change created geographically widespread conditions conducive to admixture between polar bears and brown bears, as is again occurring today. We postulate that this model will be informative for many admixing species pairs impacted by climate change. Our results highlight the power of paleogenomics to reveal patterns of evolutionary change that are otherwise masked in contemporary data.

  19. Vibration quenching in a large scale rotor-bearing system using journal bearings with variable geometry

    Science.gov (United States)

    Chasalevris, Athanasios; Dohnal, Fadi

    2014-03-01

    In large scale rotating machinery the resonance amplitude during the passage through resonance is a matter of consideration because of its influence in the surrounding environment of the rotational system and foundation. In this paper, a variable geometry journal bearing (VGJB), recently patented, is applied for the mounting of a large scale rotor bearing system operating at the range of medium speed. The simulation of the rotor-bearing system incorporates a recent method for simulation of a multi-segment continuous rotor in combination with nonlinear bearing forces. The use of the current bearing gives results that encourage the use of such a bearing in rotating machinery since the vibration amplitude during the passage through the critical speed can be reduced up to 60-70%. In the presented study, the developed amplitude and the rotor stresses are severely reduced compared to those of the system with normal cylindrical journal bearings during a virtual start up of the system.

  20. EEMD-based multiscale ICA method for slewing bearing fault detection and diagnosis

    Science.gov (United States)

    Žvokelj, Matej; Zupan, Samo; Prebil, Ivan

    2016-05-01

    A novel multivariate and multiscale statistical process monitoring method is proposed with the aim of detecting incipient failures in large slewing bearings, where subjective influence plays a minor role. The proposed method integrates the strengths of the Independent Component Analysis (ICA) multivariate monitoring approach with the benefits of Ensemble Empirical Mode Decomposition (EEMD), which adaptively decomposes signals into different time scales and can thus cope with multiscale system dynamics. The method, which was named EEMD-based multiscale ICA (EEMD-MSICA), not only enables bearing fault detection but also offers a mechanism of multivariate signal denoising and, in combination with the Envelope Analysis (EA), a diagnostic tool. The multiscale nature of the proposed approach makes the method convenient to cope with data which emanate from bearings in complex real-world rotating machinery and frequently represent the cumulative effect of many underlying phenomena occupying different regions in the time-frequency plane. The efficiency of the proposed method was tested on simulated as well as real vibration and Acoustic Emission (AE) signals obtained through conducting an accelerated run-to-failure lifetime experiment on a purpose-built laboratory slewing bearing test stand. The ability to detect and locate the early-stage rolling-sliding contact fatigue failure of the bearing indicates that AE and vibration signals carry sufficient information on the bearing condition and that the developed EEMD-MSICA method is able to effectively extract it, thereby representing a reliable bearing fault detection and diagnosis strategy.

  1. Embeddability behaviour of tin-based bearing material in dry sliding

    Energy Technology Data Exchange (ETDEWEB)

    Zeren, Adalet [University of Kocaeli, Faculty of Engineering, Department of Mechanical Engineering, Vinsan Campus, Kocaeli (Turkey)]. E-mail: adaletz@kou.edu.tr

    2007-07-01

    In this study, tin-based bearing material has been investigated in dry sliding conditions. The low Sb content (7%) is known as SAE 12 and is Sn-Sb-Cu alloy and is widely used in the automotive industry. Wear and friction characteristics were determined with respect to sliding distance, sliding speed and bearing load, using a Tecquipment HFN type 5 journal bearing test equipment. Scanning electron microscopy (SEM) and energy-disperse X-ray spectrography (EDX) are used to understand the tribological events, especially embeddability. Thus, the purpose of this study is to investigate the tribological properties of tin-based bearing alloy used especially in heavy industrial service conditions. Tests were carried out in dry sliding conditions, since despite the presence of lubricant film, under heavy service conditions dry sliding may occur from time to time, causing local wear. As a result of local wear, bearing materials and bearing may be out of their tolerance limits in their early lifetime. Embeddability is an important property due to inversely affecting the hardness and the strength of the bearing.

  2. Influence of unbalance levels on nonlinear dynamics of a rotor-backup rolling bearing system

    Science.gov (United States)

    Fonseca, Cesar A.; Santos, Ilmar F.; Weber, Hans I.

    2017-04-01

    Rotor drops in magnetic bearing and unbalance in rotors have been objective of study for many years. The combination of these two well-known phenomena led to an interesting chaotic response, when the rotor touches the inner race of the back-up bearing. The present work explores the nonlinear rotor backup bearing dynamics both theoretically and experimentally using a fully instrumented test rig, where the position of shaft, its angular velocity and the contact forces between the shaft and the backup bearing are sampled at 25 kHz. The test rig is built by a removable passive magnetic bearing, which allows for simulation of magnetic bearing failure (loss of carrying capacity and rotor fall). The rotor is studied numerically as well as experimentally. A theoretical approach is given beforehand and supplies the basis of the study. Finally the presented results are commented on the point of view of nonlinear dynamics applied to the practical use. The theoretical and numerical analyses are shown through orbit plots, phase plans, Poincaré maps, force response in time and double sided spectrum. The latter is important to characterize the condition at different levels of unbalance between forward and backward whirl. Our preliminary results indicate that for smaller amount of unbalance the rotor swings at the bottom of the bearing, the more the unbalance increases, other dynamical behavior occur and some can be extremely harmful, since the rotor can be lifted from the contact state and return, starting to impact innumerable times without reaching a steady state.

  3. Improvement of Bearing Capacity of Shallow Foundation on Geogrid Reinforced Silty Clay and Sand

    Directory of Open Access Journals (Sweden)

    P. K. Kolay

    2013-01-01

    Full Text Available The present study investigates the improvement in the bearing capacity of silty clay soil with thin sand layer on top and placing geogrids at different depths. Model tests were performed for a rectangular footing resting on top of the soil to establish the load versus settlement curves of unreinforced and reinforced soil system. The test results focus on the improvement in bearing capacity of silty clay and sand on unreinforced and reinforced soil system in non-dimensional form, that is, BCR. The results show that bearing capacity increases significantly with the increased number of geogrid layers. The bearing capacity for the soil increases with an average of 16.67% using one geogrid layer at interface of soils with equal to 0.667 and the bearing capacity increases with an average of 33.33% while using one geogrid in middle of sand layer with equal to 0.33. The improvement in bearing capacity for sand underlain silty clay maintaining and equal to 0.33; for two, three and four number geogrid layer were 44.44%, 61.11%, 72.22%, respectively. The finding of this research work may be useful to improve the bearing capacity of soil for shallow foundation and pavement design for similar type of soil available elsewhere.

  4. Experimental research and development of main circulation pump bearings in reactor plants using heavy liquid-metal coolants

    International Nuclear Information System (INIS)

    Zudin, A.; Beznosov, A.; Chernysh, A.; Prikazchikov, G.

    2015-01-01

    At the present time, specialists in Russia are engaged in designing the BREST-OD-300 fast neutron lead-coolant reactor plant. There is currently no experience in designing and operating axial pumps of lead-coolant reactor plants, including one of their major units – bearing unit. Selection and substantiation of operating and structural parameters of plain friction bearings used in main circulation pumps of reactor plants running on heavy liquid-metal coolants are important tasks that are solved at the NNSTU. Development of a feasible procedure for designing bearings and its components operating within the structure of the main circulation pump of a reactor plant running on a heavy liquid-metal coolant as well as guidelines for an optimized structural scheme of such bearings set a goal of performing a range of theoretically-calculated and experimental works. The report contains testing data of a hydrostatic bearing with reciprocal fricative choking tested on the NNSTU FT-4 bench running on a lead coolant within the range of 420-500degC. There have been presented a scheme of a bench for testing a contact friction bearing on a high-temperature coolant and the results of investigation tests of bearings of such type at T = 450 ÷ 500degC. Material of the bearing sleeve is steel 08X18H10T, and a possibility is provided with regard to installation of the bearing sleeves and shaft made of non-metal materials (ceramic materials, silicified graphite, etc.). The presented testing data of plain friction bearings operating in a high-temperature heavy liquid-metal coolant will serve as a ground for making an alternative choice of a plain friction bearing for the main circulation pump of a reactor plant running on a heavy liquid-metal coolant. (author)

  5. Rolling bearing fault diagnosis based on information fusion using Dempster-Shafer evidence theory

    Science.gov (United States)

    Pei, Di; Yue, Jianhai; Jiao, Jing

    2017-10-01

    This paper presents a fault diagnosis method for rolling bearing based on information fusion. Acceleration sensors are arranged at different position to get bearing vibration data as diagnostic evidence. The Dempster-Shafer (D-S) evidence theory is used to fuse multi-sensor data to improve diagnostic accuracy. The efficiency of the proposed method is demonstrated by the high speed train transmission test bench. The results of experiment show that the proposed method in this paper improves the rolling bearing fault diagnosis accuracy compared with traditional signal analysis methods.

  6. Shaft Voltage and Life of Bearing electric-erosion for the Brushless DC Motor

    Science.gov (United States)

    Maetani, Tatsuo; Isomura, Yoshinori; Komiyama, Hiroshi; Morimoto, Shigeo

    This paper describes the life of noise of bearing electro-erosion in the shaft voltage of brushless DC motors. We confirmed that shaft voltage is suppressed to equal to or less than the dielectric breakdown voltage of bearing lubricant in the insulated rotor proposed for suppression of shaft voltage. However, since bearing electro-erosion appears over time along with the deterioration of noise performance, the threshold of the shaft voltage to secure noise performance over long periods of time is necessary. Therefore, the threshold of the shaft voltage that influences the life of noise was obtained in acceleration tests.

  7. Bearing Fault Detection Based on Maximum Likelihood Estimation and Optimized ANN Using the Bees Algorithm

    Directory of Open Access Journals (Sweden)

    Behrooz Attaran

    2015-01-01

    Full Text Available Rotating machinery is the most common machinery in industry. The root of the faults in rotating machinery is often faulty rolling element bearings. This paper presents a technique using optimized artificial neural network by the Bees Algorithm for automated diagnosis of localized faults in rolling element bearings. The inputs of this technique are a number of features (maximum likelihood estimation values, which are derived from the vibration signals of test data. The results shows that the performance of the proposed optimized system is better than most previous studies, even though it uses only two features. Effectiveness of the above method is illustrated using obtained bearing vibration data.

  8. An Unsteady Long Bearing Squeeze Film Damper Model. Part 1; Circular Centered Orbits

    Science.gov (United States)

    Schallhorn, P. A.; Elrod, D. A.; Goggin, D. G.; Majumdar, A. K.

    2000-01-01

    This paper, the first of a two-part series, presents results of an unsteady rotordynamic analysis of a long-bearing squeeze film damper executing circular centered orbits using a fluid circuit approach. A series of nodes and branches represent the geometry of the flow circuit. The mass and momentum conservation equations are solved to predict the pressure distribution in the squeeze film. The motion of the bearing is simulated by the variation of geometry within the flow path. The modeling methodology is benchmarked against published experimental long-bearing squeeze film damper test results. The model provides good agreement with the experimental damping coefficient.

  9. A Optimal Dimension Parameters Design of Needle Roller Bearings Considering Multi Factors Affecting Life

    Science.gov (United States)

    Bai, XiaoBo; Li, Bo

    2017-12-01

    Taking into many influencing factors, a Needle Roller Bearings life calculation model was established using the Influence coefficient method and ISO formula. Take this model as the optimization objective function, some optimization variables were determined, and these variables were added constraint conditions. Using dynamic nonlinear strategy to improve the inertia weight, the arccosine strategy to adjust the learning factor, function constraints was solved by the methods of ensure particle legitimacy. Nonlinear optimization design of cylindrical roller bearings was realized by Improved Particle Swarm Algorithm. The proposed method of bearing design was verified effective by test of the optimization results.

  10. Polar bears and sea ice habitat change

    Science.gov (United States)

    Durner, George M.; Atwood, Todd C.; Butterworth, Andy

    2017-01-01

    The polar bear (Ursus maritimus) is an obligate apex predator of Arctic sea ice and as such can be affected by climate warming-induced changes in the extent and composition of pack ice and its impacts on their seal prey. Sea ice declines have negatively impacted some polar bear subpopulations through reduced energy input because of loss of hunting habitats, higher energy costs due to greater ice drift, ice fracturing and open water, and ultimately greater challenges to recruit young. Projections made from the output of global climate models suggest that polar bears in peripheral Arctic and sub-Arctic seas will be reduced in numbers or become extirpated by the end of the twenty-first century if the rate of climate warming continues on its present trajectory. The same projections also suggest that polar bears may persist in the high-latitude Arctic where heavy multiyear sea ice that has been typical in that region is being replaced by thinner annual ice. Underlying physical and biological oceanography provides clues as to why polar bear in some regions are negatively impacted, while bears in other regions have shown no apparent changes. However, continued declines in sea ice will eventually challenge the survival of polar bears and efforts to conserve them in all regions of the Arctic.

  11. Genetic control of biennial bearing in apple

    Science.gov (United States)

    Guitton, Baptiste; Kelner, Jean-Jacques; Velasco, Riccardo; Gardiner, Susan E.; Chagné, David; Costes, Evelyne

    2012-01-01

    Although flowering in mature fruit trees is recurrent, floral induction can be strongly inhibited by concurrent fruiting, leading to a pattern of irregular fruiting across consecutive years referred to as biennial bearing. The genetic determinants of biennial bearing in apple were investigated using the 114 flowering individuals from an F1 population of 122 genotypes, from a ‘Starkrimson’ (strong biennial bearer)בGranny Smith’ (regular bearer) cross. The number of inflorescences, and the number and the mass of harvested fruit were recorded over 6 years and used to calculate 26 variables and indices quantifying yield, precocity of production, and biennial bearing. Inflorescence traits exhibited the highest genotypic effect, and three quantitative trait loci (QTLs) on linkage group (LG) 4, LG8, and LG10 explained 50% of the phenotypic variability for biennial bearing. Apple orthologues of flowering and hormone-related genes were retrieved from the whole-genome assembly of ‘Golden Delicious’ and their position was compared with QTLs. Four main genomic regions that contain floral integrator genes, meristem identity genes, and gibberellin oxidase genes co-located with QTLs. The results indicated that flowering genes are less likely to be responsible for biennial bearing than hormone-related genes. New hypotheses for the control of biennial bearing emerged from QTL and candidate gene co-locations and suggest the involvement of different physiological processes such as the regulation of flowering genes by hormones. The correlation between tree architecture and biennial bearing is also discussed. PMID:21963613

  12. Genomic sequencing of Pleistocene cave bears

    Energy Technology Data Exchange (ETDEWEB)

    Noonan, James P.; Hofreiter, Michael; Smith, Doug; Priest, JamesR.; Rohland, Nadin; Rabeder, Gernot; Krause, Johannes; Detter, J. Chris; Paabo, Svante; Rubin, Edward M.

    2005-04-01

    Despite the information content of genomic DNA, ancient DNA studies to date have largely been limited to amplification of mitochondrial DNA due to technical hurdles such as contamination and degradation of ancient DNAs. In this study, we describe two metagenomic libraries constructed using unamplified DNA extracted from the bones of two 40,000-year-old extinct cave bears. Analysis of {approx}1 Mb of sequence from each library showed that, despite significant microbial contamination, 5.8 percent and 1.1 percent of clones in the libraries contain cave bear inserts, yielding 26,861 bp of cave bear genome sequence. Alignment of this sequence to the dog genome, the closest sequenced genome to cave bear in terms of evolutionary distance, revealed roughly the expected ratio of cave bear exons, repeats and conserved noncoding sequences. Only 0.04 percent of all clones sequenced were derived from contamination with modern human DNA. Comparison of cave bear with orthologous sequences from several modern bear species revealed the evolutionary relationship of these lineages. Using the metagenomic approach described here, we have recovered substantial quantities of mammalian genomic sequence more than twice as old as any previously reported, establishing the feasibility of ancient DNA genomic sequencing programs.

  13. Non-linear journal bearing model for analysis of superharmonic vibrations of rotor systems

    Energy Technology Data Exchange (ETDEWEB)

    Hannukainen, P.

    2008-07-01

    -idealities can be captured in the analysis. Additionally one non-ideality is presented that does not excite the vibrations itself but affects the response of the rotorbearing system, namely the waviness of the bearing bushing which is the non-rotating part of the bearing system. The modelled system is verified with measurements performed on a test rig. In the measurements the waviness of bearing bushing was not measured and therefore it's affect on the response was not verified. In conclusion, the selected modelling approach is an appropriate method when analysing the response of the rotor-bearing system. When comparing the simulated results to the measured ones, the overall agreement between the results is concluded to be good. (orig.)

  14. Correlation of psychomotor findings and the ability to partially weight bear

    Science.gov (United States)

    2012-01-01

    Background Partial weight bearing is thought to avoid excessive loading that may interfere with the healing process after surgery of the pelvis or the lower extremity. The object of this study was to investigate the relationship between the ability to partially weight bear and the patient's psychomotor skills and an additional evaluation of the possibility to predict this ability with a standardized psychomotor test. Methods 50 patients with a prescribed partial weight bearing at a target load of 15 kg following surgery were verbally instructed by a physical therapist. After the instruction and sufficient training with the physical therapist vertical ground reaction forces using matrix insoles were measured while walking with forearm crutches. Additionally, psychomotor skills were tested with the Motorische Leistungsserie (MLS). To test for correlations Spearman's Rank correlation was used. For further comparison of the two groups a Mann-Withney test was performed using Bonferroni correction. Results The patient's age and body weight significantly correlated with the ability to partially weight bear at a 15 kg target load. There were significant correlations between several subtests of the MLS and ground reaction forces measured while walking with crutches. Patients that were able to correctly perform partial weight bearing showed significant better psychomotor skills especially for those subtests where both hands had to be coordinated simultaneously. Conclusions The ability to partially weight bear is associated with psychomotor skills. The MLS seems to be a tool that helps predicting the ability to keep within the prescribed load limits. PMID:22330655

  15. Correlation of psychomotor findings and the ability to partially weight bear

    Directory of Open Access Journals (Sweden)

    Ruckstuhl Thomas

    2012-02-01

    Full Text Available Abstract Background Partial weight bearing is thought to avoid excessive loading that may interfere with the healing process after surgery of the pelvis or the lower extremity. The object of this study was to investigate the relationship between the ability to partially weight bear and the patient's psychomotor skills and an additional evaluation of the possibility to predict this ability with a standardized psychomotor test. Methods 50 patients with a prescribed partial weight bearing at a target load of 15 kg following surgery were verbally instructed by a physical therapist. After the instruction and sufficient training with the physical therapist vertical ground reaction forces using matrix insoles were measured while walking with forearm crutches. Additionally, psychomotor skills were tested with the Motorische Leistungsserie (MLS. To test for correlations Spearman's Rank correlation was used. For further comparison of the two groups a Mann-Withney test was performed using Bonferroni correction. Results The patient's age and body weight significantly correlated with the ability to partially weight bear at a 15 kg target load. There were significant correlations between several subtests of the MLS and ground reaction forces measured while walking with crutches. Patients that were able to correctly perform partial weight bearing showed significant better psychomotor skills especially for those subtests where both hands had to be coordinated simultaneously. Conclusions The ability to partially weight bear is associated with psychomotor skills. The MLS seems to be a tool that helps predicting the ability to keep within the prescribed load limits.

  16. Study on design procedure of three-dimensional building base isolation system using thick rubber bearing

    International Nuclear Information System (INIS)

    Yabana, Shuichi; Matsuda, Akihiro

    2003-01-01

    In this study, design procedure on three-dimensional base isolation system is developed. Base isolation system proposed by CRIEPI uses thick rubber bearing and damper as isolation device. As for thick rubber bearings, design formula for evaluating vertical stiffness is proposed, and design conditions regarding size and vertical pressure are investigated. Figure-U type lead damper is proposed as three-dimensional damper and by loading tests its mechanical characteristics is evaluated. The concept of multi-layered interconnected rubber bearing, which is advantageous over large scale bearing in manufacturability, is proposed and its good performance is confirmed by the loading test. Through the response analyses, it is shown the rocking response of the proposed three-dimensional base isolation system is very small and not influential to the system, and the reduction of the vertical response is attained using the proposed isolation device. (author)

  17. Control of Surge in Centrifugal Compressors by Active Magnetic Bearings Theory and Implementation

    CERN Document Server

    Yoon, Se Young; Allaire, Paul E

    2013-01-01

    Control of Surge in Centrifugal Compressors by Active Magnetic Bearings sets out the fundamentals of integrating the active magnetic bearing (AMB) rotor suspension technology in compressor systems, and describes how this relatively new bearing technology can be employed in the active control of compressor surge. The authors provide a self-contained and comprehensive review of rotordynamics and the fundamentals of the AMB technology. The active stabilization of compressor surge employing AMBs in a machine is fully explored, from the modeling of the instability and the design of feedback controllers, to the implementation and experimental testing of the control algorithms in a specially-constructed, industrial-size centrifugal compression system. The results of these tests demonstrate the great potential of the new surge control method developed in this text. This book will be useful for engineers in industries that involve turbocompressors and magnetic bearings, as well as for researchers and graduate students...

  18. On the Characteristics of Misaligned Journal Bearings

    Directory of Open Access Journals (Sweden)

    Joon Young Jang

    2015-03-01

    Full Text Available Journal bearing misalignment arise generally from the shaft deformation under load, deflection of the shaft, manufacturing and assembly errors, improper installation, and asymmetric loading. During operations, misalignment has a considerable effect on the static and dynamic performances. It could cause wear, vibration and even system failure. In this article, a literature review of misalignment of the journal bearings is presented. The basic theory for the misalignment and some results for the circular journal bearing are also presented to show the general trends of the misalignment.

  19. Microeconomic analysis of military aircraft bearing restoration

    Science.gov (United States)

    Hein, G. F.

    1976-01-01

    The risk and cost of a bearing restoration by grinding program was analyzed. A microeconomic impact analysis was performed. The annual cost savings to U.S. Army aviation is approximately $950,000.00 for three engines and three transmissions. The capital value over an indefinite life is approximately ten million dollars. The annual cost savings for U.S. Air Force engines is approximately $313,000.00 with a capital value of approximately 3.1 million dollars. The program will result in the government obtaining bearings at lower costs at equivalent reliability. The bearing industry can recover lost profits during a period of reduced demand and higher costs.

  20. Camshaft bearing arrangement for overhead cam engine

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, M.

    1985-01-01

    In an assembly for an internal combustion engine comprising a cylinder block, a cylinder head detachably affixed to the cylinder block by a plurality of threaded fastening means, a plurality of poppet valves supported for reciprocation in the cylinder head and a camshaft for operating the poppet valves, the improvement is described comprising a cam carrier detachably affixed to the cylinder head and overlying the threaded fastening means, and a bearing cap affixed to the cam carrier. The cam carrier and the bearing cap have bearing surfaces for journaling the camshaft.

  1. Rotational decay torques of superconducting magnetic bearing

    International Nuclear Information System (INIS)

    Takahata, R.; Yotsuya, T.

    1991-01-01

    This paper proposes a superconducting magnetic bearing as one of application of a high critical temperature (Tc) oxide superconducting material. The authors have assembled new models of bearing with free rotation axis. In these models, superconductor, YBa 2 Cu 3 O X , prepared by the quench and melt growth (QMG) method was applied to the bearing section and a permanent magnet was used for a rotor. This development originated from the knowledge that YBa 2 Cu 3 O X prepared by QMG method had a stronger pinning force of magnetic flux than that of conventional superconductors

  2. Compressor ported shroud for foil bearing cooling

    Science.gov (United States)

    Elpern, David G [Los Angeles, CA; McCabe, Niall [Torrance, CA; Gee, Mark [South Pasadena, CA

    2011-08-02

    A compressor ported shroud takes compressed air from the shroud of the compressor before it is completely compressed and delivers it to foil bearings. The compressed air has a lower pressure and temperature than compressed outlet air. The lower temperature of the air means that less air needs to be bled off from the compressor to cool the foil bearings. This increases the overall system efficiency due to the reduced mass flow requirements of the lower temperature air. By taking the air at a lower pressure, less work is lost compressing the bearing cooling air.

  3. Steady state characteristics of a tilting pad journal bearing with controllable lubrication: Comparison between theoretical and experimental results

    DEFF Research Database (Denmark)

    Cerda Varela, Alejandro Javier; Nielsen, Bo Bjerregaard; Santos, Ilmar

    2013-01-01

    direction. The modification of the injection pressure enables to modify the bearing static and dynamic properties according to the operational needs. The results presented are obtained using a theoretical model, which considers all the effects that determine the bearing behavior (controllable......This paper is aimed at presenting results regarding the static and thermal behavior of a tilting-pad journal bearing operating under controllable regime. The bearing is rendered controllable by injecting high pressure oil into the clearance using holes drilled across the bearing pads in the radial...... elastothermohydrodynamic lubrication regime), as well as using a test rig designed and built to this effect. The comparison between experimental and theoretical results provides solid ground to determine the accuracy of the available model for the the prediction of the steady-state behavior of the tilting-pad bearing...

  4. Public Perceptions of Bears and Management Interventions in Japan

    OpenAIRE

    Sakurai, Ryo; Jacobson, Susan K.

    2011-01-01

    Conservation of bears is a challenge globally. In Japan, Asiatic black bears (Ursus thibetanus) and brown bears (Ursus arctos) are considered a nuisance because of agricultural and property damage and personal human danger due to occasional human casualties. Reduction of human–bear conflicts in Japan would improve long-term conservation of bears and reduce risks to human health and safety. To understand Japanese perceptions of and experience with bears, we analyzed results of 5 public surveys...

  5. Management of brown bears (Ursus arctos) in Europe.

    OpenAIRE

    Klenzendorf, Sybille A.

    1997-01-01

    Management of Brown Bears (Ursus arctos) in Europe. Sybille A. Klenzendorf (Abstract) Successful conservation of brown bears (Ursus arctos) in Europe is associated with public acceptance of damages caused by bears. Recent increases in sheep depredation and beehive damage in central Austria resulted in the deaths of two bears there. Since bear numbers are low in most European populations, alternatives to the elimination of problem bears associated with dam...

  6. Differences between blood and a Newtonian fluid on the performance of a hydrodynamic bearing for rotary blood pumps.

    Science.gov (United States)

    Amaral, Felipe; Egger, Christina; Steinseifer, Ulrich; Schmitz-Rode, Thomas

    2013-09-01

    Assuming that blood has a constant viscosity is a common practice when designing rotary blood pumps (RBPs), where shear stresses are generally higher than in the human body. This eases the design and allows numerical simulations and bench top experiments to be performed with Newtonian fluids. However, specific flow conditions may cause a change in cell distribution leading to an apparent lower blood viscosity. It has been observed that decreasing the vessel diameters and increasing flow velocities contribute to this effect. Because a hydrodynamic bearing operates under flow conditions following this pattern, it is important to verify whether this effect also takes place when this type of bearing is applied to a RBP. Because the operation of a hydrodynamic bearing depends directly on the fluid viscosity, a local change in cell distribution in the bearing gap can be reflected in changes in the bearing performance. In this work, a spiral groove hydrodynamic bearing was tested with porcine blood in a specially built test rig. The generated suspension force, cross flow, and bearing torque were recorded and compared with the reference response when using a solution of water and glycerol. Experiments with porcine blood yielded lower suspension forces, lower flows, and lower bearing torques than when using the glycerol solution. An explanation could be a lower apparent viscosity due to inhomogeneity of blood cell concentrations. Therefore, it is crucial to consider the effective blood viscosity when designing hydrodynamic bearings for RBPs and performing experiments. © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

  7. Method for Vibration Response Simulation and Sensor Placement Optimization of a Machine Tool Spindle System with a Bearing Defect

    Science.gov (United States)

    Cao, Hongrui; Niu, Linkai; He, Zhengjia

    2012-01-01

    Bearing defects are one of the most important mechanical sources for vibration and noise generation in machine tool spindles. In this study, an integrated finite element (FE) model is proposed to predict the vibration responses of a spindle bearing system with localized bearing defects and then the sensor placement for better detection of bearing faults is optimized. A nonlinear bearing model is developed based on Jones' bearing theory, while the drawbar, shaft and housing are modeled as Timoshenko's beam. The bearing model is then integrated into the FE model of drawbar/shaft/housing by assembling equations of motion. The Newmark time integration method is used to solve the vibration responses numerically. The FE model of the spindle-bearing system was verified by conducting dynamic tests. Then, the localized bearing defects were modeled and vibration responses generated by the outer ring defect were simulated as an illustration. The optimization scheme of the sensor placement was carried out on the test spindle. The results proved that, the optimal sensor placement depends on the vibration modes under different boundary conditions and the transfer path between the excitation and the response. PMID:23012514

  8. When top predators become prey: Black bears alter movement behaviour in response to hunting pressure.

    Science.gov (United States)

    Stillfried, Milena; Belant, Jerrold L; Svoboda, Nathan J; Beyer, Dean E; Kramer-Schadt, Stephanie

    2015-11-01

    The trade-off between predator avoidance and foraging is a key decision making factor that shapes an organism's adaptive behaviour and movement patterns. Human hunters act as top predators to influence the behaviour of free-ranging mammals, including large carnivorous species such as black bears (Ursus americanus). Analysing the effects of hunting on animal behavioural patterns is essential for understanding the extent to which animals detect and respond to human-induced disturbances. To this end, we assessed whether black bear movement behaviour changed with varying risk from spatially and temporally heterogeneous human predation. Levels of risk were categorized as either low (disturbance from dog training; n=19 bears) or high (disturbance from hunting activities; n=11 bears). Road types were either paved (risk due to vehicles) or non-paved (risk due to hunters) and were used as proxies for hunting effort and amount of disturbance. We began by testing the null hypothesis that bears' distribution before the onset of human disturbance is spatially random. Next, to test temporal movement adjustment between the low and high risk levels, we measured the distance to the nearest road and the road crossing frequency using mixed effects models with risk level, time of day and sex as predictor variables. As disturbance near non-paved roads increased due to the start of the hunting activity, the mean distances of bears to non-paved roads increased while the mean distances of bears to paved roads decreased, despite the continual risk of vehicle collision. These behavioural responses were observed during day and night, with the frequency of crossing paved roads at night five times greater than in daytime during the hunting season. Our findings demonstrate that black bears are able to detect risky places and adjust their spatial movements accordingly. More specifically, bears can perceive changes in the level of risk from human hunting activities on a fine temporal scale

  9. Vibration of a rotating shaft on hydrodynamic bearings: multi-scales surface effects

    International Nuclear Information System (INIS)

    Rebufa, Jocelyn

    2016-01-01

    The hydrodynamic bearing provides good damping properties in rotating machineries. However, the performances of rotor-bearings systems are highly impacted by nonlinear effects that are difficult to analyze. The rotor dynamics prediction requires advanced models for the flow in the bearings. The surface of the bearings seems to have a strong impact on the lubricant flow, acting on the static and dynamic properties of the rotating parts. This study aims to enhance the simulation of the bearings' surface state effect on the motion of the rotating shaft. The flexible shaft interacts with textured hydrodynamic bearings. Multi-scales homogenization is used in a multi-physics algorithm in order to describe the fluid-structure interaction. Different models are used to account for the cavitation phenomenon in the bearings. Nonlinear harmonic methods allow efficient parametric studies of periodic solutions as well as their stability. Moreover, a test rig has been designed to compare predictions to real measurements. Several textured shaft samples modified with femto-seconds LASER surface texturing are tested. In most cases the experimental study showed similar results than the simulation. Enhancements of the vibration behaviors of the rotor-bearing system have been revealed for certain texturing patterns. The self-excited vibration, also known as 'oil whirl' phenomenon, is stabilized on a wide rotating frequency range. However, the simulation tool does not predict well the enhancements that are observed. Vortices in surface texturing patterns have been revealed numerically with Navier-Stokes equation resolution. These results are opposed to the classical lubrication hypothesis. It is also a possible explanation of the enhancements that are experimentally measured with textured bearings. (author) [fr

  10. Tetranucleotide microsatellite loci from the black bear (Ursus americanus)

    Science.gov (United States)

    Sanderlin, J.S.; Faircloth, B.C.; Shamblin, B.; Conroy, M.J.

    2009-01-01

    We describe primers and polymerase chain reaction conditions to amplify 21 tetranucleotide microsatellite DNA loci in black bears (Ursus americanus). We tested primers using individuals from two populations, one each in Georgia and Florida. Among individuals from Georgia (n = 29), primer pairs yielded an average of 2.9 alleles (range, one to four) and an average observed heterozygosity (HO) of 0.50 (range, 0.00 to 0.79). Among individuals from Florida (n = 19), primer pairs yielded an average of 5.7 alleles (range, one to 14) and an HO of 0.55 (range, 0.00 to 1.00). A comparison of previously developed markers with individuals from Georgia suggests that bear populations in Georgia and Florida have reduced allelic diversity relative to other populations. ?? 2008 The Authors.

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

    Science.gov (United States)

    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.

  12. The in-vacuo torque performance of dry-lubricated ball bearings at cryogenic temperatures

    Science.gov (United States)

    Gould, S. G.; Roberts, E. W.

    1989-01-01

    The performance of dry-lubricated, angular contact ball bearings in vacuum at a temperature of 20 degrees K has been investigated, and is compared with the in-vacuo performance at room temperatures. Bearings were lubricated using dry-lubricant techniques which have been previously established for space applications involving operations at or near room temperature. Comparative tests were undertaken using three lubricants: molybdenum disulphide, lead, and PTFE. Results obtained using the three lubricants are presented.

  13. Effects of various treatments on the serviceability of water-immersed carbon-steel ball bearings

    International Nuclear Information System (INIS)

    Wensel, R.G.

    1977-06-01

    Carbon-steel ball bearings employing various coatings, surface treatments, lubricants and ball and separator materials were tested under conditions simulating those in the NPD/Bruce type fuelling machine heads. The effects of the treatments on operating torques and wear and corrosion rates were studied. Sealed bearings lubricated with Dow FS 3451 (a fluorosilicone grease) gave the best performance in terms of these parameters. (author)

  14. Trichinella Surveillance in Black Bears ( Ursus americanus ) from the Dehcho Region, Northwest Territories, Canada, 2002-15.

    Science.gov (United States)

    Larter, Nicholas C; Elkin, Brett T; Forbes, Lorry B; Wagner, Brent; Allaire, Danny G

    2017-04-01

    We used muscle digestion to test black bears ( Ursus americanus ) from the southwestern Northwest Territories, Canada, for Trichinella. Results showed a prevalence of 4.1%. Some bears had infection intensities of more than one larva per gram of muscle tissue; this level in meat is considered to pose a human consumption safety risk.

  15. State Space Formulation of Nonlinear Vibration Responses Collected from a Dynamic Rotor-Bearing System: An Extension of Bearing Diagnostics to Bearing Prognostics

    OpenAIRE

    Peter W. Tse; Dong Wang

    2017-01-01

    Bearings are widely used in various industries to support rotating shafts. Their failures accelerate failures of other adjacent components and may cause unexpected machine breakdowns. In recent years, nonlinear vibration responses collected from a dynamic rotor-bearing system have been widely analyzed for bearing diagnostics. Numerous methods have been proposed to identify different bearing faults. However, these methods are unable to predict the future health conditions of bearings. To exten...

  16. Vibration Characteristics of Hydrodynamic Fluid Film Pocket Journal Bearings

    Directory of Open Access Journals (Sweden)

    N. S. Feng

    2010-01-01

    Full Text Available Theoretical analyses of hydrodynamic fluid film bearings with different bearing profiles rely on solutions of the Reynolds equation. This paper presents an approach used for analysing the so-called pocket bearings formed from a combination of offset circular bearing profiles. The results show that the variation of the dynamic bearing characteristics with different load inclinations for the pocket bearings is less than that for the elliptic bearing counterpart. It is shown that the natural frequencies as well as the critical speeds, and hence the vibrational behaviour, can also be significantly different for an industrial rotor supported by the different bearings.

  17. Bearing gap adjustment for improvement of levitation performance in a hydrodynamically levitated centrifugal blood pump.

    Science.gov (United States)

    Kosaka, Ryo; Yoshida, Fumihiko; Nishida, Masahiro; Maruyama, Osamu; Kawaguchi, Yasuo; Yamane, Takashi

    2015-01-01

    The purpose of the present study is to investigate a bearing gap adjustment for improvement of levitation performance in a hydrodynamically levitated centrifugal blood pump to realize a blood pump with a low hemolysis level. The impeller levitates axially by balancing a gravitational force, buoyancy, a magnetic force, and hydrodynamic forces on the top and bottom sides of the impeller. To adjust the levitation position of the impeller, the balance of acting forces on the impeller was adjusted by changing the shroud area on the bottom impeller. Three pumps having various shroud area were prepared as tested models: 817 mm(2) (HH-S), 875 mm(2) (HH-M) and 931 mm(2) (HH-L). First, for evaluating the bearing gap adjustment, the bearing gap was estimated by calculating a balancing position of the acting forces on the impeller. We actually measured the gravitational force, buoyancy and the magnetic force, and numerically analyzed hydrodynamic forces on the top and bottom sides of the impeller. Second, to verify accuracy of the estimated bearing gap, the measurement test of the bearing gap was performed. Finally, an in-vitro hemolysis test was performed to evaluate a hemolysis level of the pump. As a result, bottom bearing gaps were estimated as 40 μm (HH-S), 60 μm (HH-M) and 238 μm (HH-L). In the measurement test, bottom bearing gaps were measured as 63 μm (HH-S), 219 μm (HH-M), and 231 μm (HH-L). The estimated bearing gaps had positively correlated with the measured bearing gaps in relation to the shroud area on the impeller. In the hemolysis test, hemolysis level in every model was almost equivalent to that of BPX-80, when the bearing gap was adjusted greater than 60 μm. We could adjust the bearing gap by changing the shroud area on the impeller for improvement of levitation performance to realize a blood pump with a low hemolysis level.

  18. LOAD BEARING CAPACITY OF THE GLASS RAILING ELEMENT

    Directory of Open Access Journals (Sweden)

    Elizabeta Šamec

    2016-02-01

    Full Text Available In this paper some basic physical and mechanical properties of glass as structural material are presented. This research is about specifically manufactured glass railing element that will be a part of a pedestrian bridge construction in Zagreb, Croatia. Load bearing capacity test of the glass railing element is conducted within the Faculty of Civil Engineering in Zagreb and obtained experimental results are discussed and compared to the ones provided by the numerical model. Taking into account the behaviour of laminated glass and results of experimental and numerical testing, glass railing element can be regarded as safe.

  19. Bearing Capacity Analysis Using Meshless Local Petrov-Galerkin Method

    Directory of Open Access Journals (Sweden)

    Mužík Juraj

    2014-05-01

    Full Text Available The paper deals with use of the meshless method for soil bearing capacity analysis. There are many formulations of the meshless methods. The article presents the Meshless Local Petrov-Galerkin method (MLPG - local weak formulation of the equilibrium equations. The main difference between meshless methods and the conventional finite element method (FEM is that meshless shape functions are constructed using randomly scattered set of points without any relation between points. The Heaviside step function is test function used in the meshless implementation presented in the article. Heaviside test function makes weak formulation integral very simple, because only body integral in governing equation is due a body force.

  20. Molecular phylogeny and SNP variation of polar bears (Ursus maritimus), brown bears (U. arctos), and black bears (U. americanus) derived from genome sequences.

    Science.gov (United States)

    Cronin, Matthew A; Rincon, Gonzalo; Meredith, Robert W; MacNeil, Michael D; Islas-Trejo, Alma; Cánovas, Angela; Medrano, Juan F

    2014-01-01

    We assessed the relationships of polar bears (Ursus maritimus), brown bears (U. arctos), and black bears (U. americanus) with high throughput genomic sequencing data with an average coverage of 25× for each species. A total of 1.4 billion 100-bp paired-end reads were assembled using the polar bear and annotated giant panda (Ailuropoda melanoleuca) genome sequences as references. We identified 13.8 million single nucleotide polymorphisms (SNP) in the 3 species aligned to the polar bear genome. These data indicate that polar bears and brown bears share more SNP with each other than either does with black bears. Concatenation and coalescence-based analysis of consensus sequences of approximately 1 million base pairs of ultraconserved elements in the nuclear genome resulted in a phylogeny with black bears as the sister group to brown and polar bears, and all brown bears are in a separate clade from polar bears. Genotypes for 162 SNP loci of 336 bears from Alaska and Montana showed that the species are genetically differentiated and there is geographic population structure of brown and black bears but not polar bears.