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Sample records for shafts bearings casing

  1. Computing Thermal Performances Of Shafts And Bearings

    NASA Technical Reports Server (NTRS)

    Woods, Claudia M.

    1992-01-01

    SHABERTH computer program developed to predict steady-state and transient thermal performance of multi-bearing shaft system operating with either wet or dry friction. Calculates loads, torques, temperatures, and fatigue lives for ball and/or roller bearings on single shaft. Enables study of many causes of instabilities in bearings. Also provides for analysis of reaction of system to termination of supply of lubricant to bearings and other lubricated mechanical elements. Valuable software tool in design and analysis of shaft bearing systems. Written in FORTRAN IV.

  2. Computing Thermal Performances Of Shafts And Bearings

    NASA Technical Reports Server (NTRS)

    Woods, Claudia M.

    1992-01-01

    SHABERTH computer program developed to predict steady-state and transient thermal performance of multi-bearing shaft system operating with either wet or dry friction. Calculates loads, torques, temperatures, and fatigue lives for ball and/or roller bearings on single shaft. Enables study of many causes of instabilities in bearings. Also provides for analysis of reaction of system to termination of supply of lubricant to bearings and other lubricated mechanical elements. Valuable software tool in design and analysis of shaft bearing systems. Written in FORTRAN IV.

  3. Turbocharger with improved roller bearing shaft support

    SciTech Connect

    Gutknecht, D.A.

    1991-10-08

    This paper describes an exhaust gas driven turbocharger. It comprises: a housing, a shaft within the housing having a pair of ends, a compressor wheel mounted within the housing on one end of the shaft for rotation therewith, a turbine wheel mounted within the housing on the other end of the shaft for rotation therewith, means for communicating air through the compressor wheel, means for communicating exhaust gas through the turbine wheel to cause the latter to rotate the shaft and the compressor wheel mounted thereon to compress the air communicated through the compressor wheel, and bearing means mounting the shaft for rotation relative to the housing, the bearing means including a bearing outer ring, a bearing inner ring, and ball bearing elements supporting the bearing outer ring on the bearing inner ring, the ball bearing elements includes a first set of the elements and a second set of the elements spaced axially from the first set, the bearing outer ring being a rigid, uninterrupted member providing an uninterrupted structural link between the first and second sets to establish the axial spacing between the sets, a pair of axially spaced faying surfaces on the inner ring engaging corresponding faying surfaces on the shaft to support the inner ring on the shaft, the shaft defining a circumferentially extending surface between the faying surfaces on the inner ring cooperating with the shaft to define an air gap therebetween, one of the faying surfaces on the inner ring having a diameter greater than the diameter of the other of the faying surfaces on the inner ring.

  4. Securing Bearing Races To Turbopump Shafts

    NASA Technical Reports Server (NTRS)

    Blount, Dale H.

    1990-01-01

    Proposed method of attaching inner race of roller bearing to shaft prevents loosening now caused by difference between coefficients of thermal expansion of race and shaft materials. Intended for cryogenic turbopump in which race made of 440C stainless-steel alloy and shaft made of Inconel(R) 100 nickel alloy. Flanges of race replaced by tension bands that shrink faster as they are cooled. Tension band engages race on slightly sloping surface so axial forces do not dislodge it.

  5. Securing Bearing Races To Turbopump Shafts

    NASA Technical Reports Server (NTRS)

    Blount, Dale H.

    1990-01-01

    Proposed method of attaching inner race of roller bearing to shaft prevents loosening now caused by difference between coefficients of thermal expansion of race and shaft materials. Intended for cryogenic turbopump in which race made of 440C stainless-steel alloy and shaft made of Inconel(R) 100 nickel alloy. Flanges of race replaced by tension bands that shrink faster as they are cooled. Tension band engages race on slightly sloping surface so axial forces do not dislodge it.

  6. Thermal performance of shaft bearing system

    NASA Technical Reports Server (NTRS)

    Crecelius, W.

    1978-01-01

    Computer program calculates loads, torques, temperature, and fatigue life of multibearing shaft system operating with either wet or dry friction. Program is also capable of predicting system reactive to termination of lubricant supply to bearings and other lubricated mechanical elements.

  7. Passive magnetic bearing for a horizontal shaft

    DOEpatents

    Post, Richard F.

    2003-12-02

    A passive magnetic bearing is composed of a levitation element and a restorative element. The levitation element is composed of a pair of stationary arcuate ferromagnetic segments located within an annular radial-field magnet array. The magnet array is attached to the inner circumference of a hollow shaft end. An attractive force between the arcuate segments and the magnet array acts vertically to levitate the shaft, and also in a horizontal transverse direction to center the shaft. The restorative element is comprised of an annular Halbach array of magnets and a stationary annular circuit array located within the Halbach array. The Halbach array is attached to the inner circumference of the hollow shaft end. A repulsive force between the Halbach array and the circuit array increases inversely to the radial space between them, and thus acts to restore the shaft to its equilibrium axis of rotation when it is displaced therefrom.

  8. Computing Operating Characteristics Of Bearing/Shaft Systems

    NASA Technical Reports Server (NTRS)

    Moore, James D.

    1996-01-01

    SHABERTH computer program predicts operating characteristics of bearings in multibearing load-support system. Lubricated and nonlubricated bearings modeled. Calculates loads, torques, temperatures, and fatigue lives of ball and/or roller bearings on single shaft. Provides for analysis of reaction of system to termination of supply of lubricant to bearings and other lubricated mechanical elements. Valuable in design and analysis of shaft/bearing systems. Two versions of SHABERTH available. Cray version (LEW-14860), "Computing Thermal Performances Of Shafts and Bearings". IBM PC version (MFS-28818), written for IBM PC-series and compatible computers running MS-DOS.

  9. Computing Operating Characteristics Of Bearing/Shaft Systems

    NASA Technical Reports Server (NTRS)

    Moore, James D.

    1996-01-01

    SHABERTH computer program predicts operating characteristics of bearings in multibearing load-support system. Lubricated and nonlubricated bearings modeled. Calculates loads, torques, temperatures, and fatigue lives of ball and/or roller bearings on single shaft. Provides for analysis of reaction of system to termination of supply of lubricant to bearings and other lubricated mechanical elements. Valuable in design and analysis of shaft/bearing systems. Two versions of SHABERTH available. Cray version (LEW-14860), "Computing Thermal Performances Of Shafts and Bearings". IBM PC version (MFS-28818), written for IBM PC-series and compatible computers running MS-DOS.

  10. Synchronous Control Effort Minimized for Magnetic-Bearing-Supported Shaft

    NASA Technical Reports Server (NTRS)

    Brown, Gerald V.

    2001-01-01

    Various disturbances that are synchronous with the shaft speed can complicate radial magnetic bearing control. These include position sensor target irregularities (runout) and shaft imbalance. The method presented here allows the controller to ignore all synchronous harmonics of the shaft position input (within the closed-loop bandwidth) and to respond only to asynchronous motions. The result is reduced control effort.

  11. DC Control Effort Minimized for Magnetic-Bearing-Supported Shaft

    NASA Technical Reports Server (NTRS)

    Brown, Gerald V.

    2001-01-01

    A magnetic-bearing-supported shaft may have a number of concentricity and alignment problems. One of these involves the relationship of the position sensors, the centerline of the backup bearings, and the magnetic center of the magnetic bearings. For magnetic bearings with permanent magnet biasing, the average control current for a given control axis that is not bearing the shaft weight will be minimized if the shaft is centered, on average over a revolution, at the magnetic center of the bearings. That position may not yield zero sensor output or center the shaft in the backup bearing clearance. The desired shaft position that gives zero average current can be achieved if a simple additional term is added to the control law. Suppose that the instantaneous control currents from each bearing are available from measurements and can be input into the control computer. If each control current is integrated with a very small rate of accumulation and the result is added to the control output, the shaft will gradually move to a position where the control current averages to zero over many revolutions. This will occur regardless of any offsets of the position sensor inputs. At that position, the average control effort is minimized in comparison to other possible locations of the shaft. Nonlinearities of the magnetic bearing are minimized at that location as well.

  12. DC Control Effort Minimized for Magnetic-Bearing-Supported Shaft

    NASA Technical Reports Server (NTRS)

    Brown, Gerald V.

    2001-01-01

    A magnetic-bearing-supported shaft may have a number of concentricity and alignment problems. One of these involves the relationship of the position sensors, the centerline of the backup bearings, and the magnetic center of the magnetic bearings. For magnetic bearings with permanent magnet biasing, the average control current for a given control axis that is not bearing the shaft weight will be minimized if the shaft is centered, on average over a revolution, at the magnetic center of the bearings. That position may not yield zero sensor output or center the shaft in the backup bearing clearance. The desired shaft position that gives zero average current can be achieved if a simple additional term is added to the control law. Suppose that the instantaneous control currents from each bearing are available from measurements and can be input into the control computer. If each control current is integrated with a very small rate of accumulation and the result is added to the control output, the shaft will gradually move to a position where the control current averages to zero over many revolutions. This will occur regardless of any offsets of the position sensor inputs. At that position, the average control effort is minimized in comparison to other possible locations of the shaft. Nonlinearities of the magnetic bearing are minimized at that location as well.

  13. Three-Wave Gas Journal Bearing Behavior With Shaft Runout

    NASA Technical Reports Server (NTRS)

    Dimofte, Florin; Hendricks, Robert C.

    1997-01-01

    Experimental orbits of a free-mounted, three-wave gas journal bearing housing were recorded and compared to transient predicted orbits. The shaft was mounted eccentric with a fixed runout. Experimental observations for both the absolute bearing housing center orbits and the relative bearing housing center to shaft center orbits are in good agreement with the predictions. The sub-synchronous whirl motion generated by the fluid film was found experimentally and predicted theoretically for certain speeds. A three-wave journal bearing can run stably under dynamic loads with orbits well inside the bearing clearance. Moreover, the orbits are almost circular free of the influence of bearing wave shape.

  14. Three-Wave Gas Journal Bearing Behavior With Shaft Runout

    NASA Technical Reports Server (NTRS)

    Dimofte, Florin; Hendricks, Robert C.

    1997-01-01

    Experimental orbits of a free-mounted, three-wave gas journal bearing housing were recorded and compared to transient predicted orbits. The shaft was mounted eccentric with a fixed runout. Experimental observations for both the absolute bearing housing center orbits and the relative bearing housing center to shaft center orbits are in good agreement with the predictions. The sub-synchronous whirl motion generated by the fluid film was found experimentally and predicted theoretically for certain speeds. A three-wave journal bearing can run stably under dynamic loads with orbits well inside the bearing clearance. Moreover, the orbits are almost circular free of the influence of bearing wave shape.

  15. Computer program analyzes whirl critical speeds and bearing loads for shafts coupled by nonlinear springs to machine housing

    NASA Technical Reports Server (NTRS)

    Severud, L. K.

    1969-01-01

    Computerized method of analysis predicts bearing loads, shaft deflections, and critical speeds for shafts coupled by rolling contact bearings to the machine housing. The bearing nonlinearities, casing as well as rotor dynamics, and rotor-imbalance forcing functions are all included in the system dynamics analysis.

  16. SHABERTH - ANALYSIS OF A SHAFT BEARING SYSTEM (CRAY VERSION)

    NASA Technical Reports Server (NTRS)

    Coe, H. H.

    1994-01-01

    The SHABERTH computer program was developed to predict operating characteristics of bearings in a multibearing load support system. Lubricated and non-lubricated bearings can be modeled. SHABERTH calculates the loads, torques, temperatures, and fatigue life for ball and/or roller bearings on a single shaft. The program also allows for an analysis of the system reaction to the termination of lubricant supply to the bearings and other lubricated mechanical elements. SHABERTH has proven to be a valuable tool in the design and analysis of shaft bearing systems. The SHABERTH program is structured with four nested calculation schemes. The thermal scheme performs steady state and transient temperature calculations which predict system temperatures for a given operating state. The bearing dimensional equilibrium scheme uses the bearing temperatures, predicted by the temperature mapping subprograms, and the rolling element raceway load distribution, predicted by the bearing subprogram, to calculate bearing diametral clearance for a given operating state. The shaft-bearing system load equilibrium scheme calculates bearing inner ring positions relative to the respective outer rings such that the external loading applied to the shaft is brought into equilibrium by the rolling element loads which develop at each bearing inner ring for a given operating state. The bearing rolling element and cage load equilibrium scheme calculates the rolling element and cage equilibrium positions and rotational speeds based on the relative inner-outer ring positions, inertia effects, and friction conditions. The ball bearing subprograms in the current SHABERTH program have several model enhancements over similar programs. These enhancements include an elastohydrodynamic (EHD) film thickness model that accounts for thermal heating in the contact area and lubricant film starvation; a new model for traction combined with an asperity load sharing model; a model for the hydrodynamic rolling and

  17. Comparative lubrication studies of OH-58A tail rotor drive shaft bearings

    NASA Technical Reports Server (NTRS)

    Dietrich, M. W.; Parker, R. J.; Zaretsky, E. V.

    1972-01-01

    Comparative lubrication tests were run with OH-58A helicopter tail rotor drive shaft bearings. The tests were run in an outdoor environment with ambient temperatures ranging from 10 to 75 F. Dust was periodically applied to the bearings to simulate field conditions. The cause of bearing failure was associated with dust penetration. Rotor shaft failure was found to be caused by the shaft rotating in the standard rubber collar due to seizure of the bearings. Bearings with a positive rubbing seal having a MIL-G-81322 grease produced lives greater than with bearings having labyrinth seals and a mineral oil paste lubricant. An elongated collar prevented failure of the rotor shaft during bearing seizure. In a limited test, installation of tail boom shrouds over the bearings which excluded dust and water resulted in bearing lives in excess of 1800 hours or 1200 hours greater than the current 600 hours TBO, regardless of the lubricant-bearing combination used.

  18. Effect of shaft frequency on cavitation in a journal bearing for noncentered circular whirl

    NASA Technical Reports Server (NTRS)

    Brewe, David E.; Khonsari, M. M.

    1987-01-01

    The effect of shaft frequency on the performance of a submerged journal undergoing noncentered circular whirl is examined. The main emphasis of the paper is on the behavior of the vapor cavitation bubble and its effect on the bearing performance as a function of frequency. A cavitation algorithm due to Elrod was implemented in a computer program which solves a time-dependent Reynolds equation. This algorithm automatically handles the boundary conditions by using a switch function and a control volume approach which conserves mass throughout the entire flow. The shaft frequencies in this investigation ranged from 0 rad/s (squeeze-film damper) to -104 rad/s (a case in which oil-whip condition was produced momentarily). For the particular vibration amplitude chosen in this investigation it was observed that vapor cavitation had an effect on the load components for the full range of shaft frequencies investigated.

  19. On the role of oil-film bearings in promoting shaft instability: Some experimental observations

    NASA Technical Reports Server (NTRS)

    Holmes, R.

    1980-01-01

    The occurrence of oil whirl instability in rigid and flexible rotor systems was investigated. The effect of various bearing parameters on the oil whirl frequency and amplitude of rigid and flexible shafts supported on fluid film bearings was also studied.

  20. Influence of bearing support structures on shaft vibration of large hydraulic pump/turbines

    SciTech Connect

    Pistner, C.A.; Greenplate, B.S.; Waddell, A.M.

    1995-12-31

    Start-up transient loads from pump/turbine impellers can cause excessive vibration problems in the shaft system. If the radial guide bearing supports are structurally soft or loose, or if the bearings are worn, the resulting radial shaft movement causes abnormal wear. The wear normally occurs at the impeller sealing surfaces, main shaft seals, motor/generator components, piping, brackets, foundation connections, etc. This paper explores the critical factors causing shaft system vibration problems at the Tennessee Valley Authority`s Raccoon Mountain Pumped Storage Plant, as well as the unique modifications which were implemented to strengthen and improve the units. The solution involved extensive three-dimensional finite element structural and thermal transient analyses of the original and re-designed turbine shoe bearing, bearing housings, and support structures. The conclusion compares the calculated and measured shaft system response to transient loads of the original and modified system.

  1. Synchronous dynamics of a coupled shaft/bearing/housing system with auxiliary support from a clearance bearing: Analysis and experiment

    NASA Technical Reports Server (NTRS)

    Lawen, James, Jr.; Flowers, George T.

    1992-01-01

    This study examines the response of a flexible rotor supported by load sharing between linear bearings and an auxiliary clearance bearing. The objective of the work is to develop a better understanding of the dynamical behavior of a magnetic bearing supported rotor system interacting with auxiliary bearings during a critical operating condition. Of particular interest is the effect of coupling between the bearing/housing and shaft vibration on the rotordynamical responses. A simulation model is developed and a number of studies are performed for various parametric configurations. An experimental investigation is also conducted to compare and verify the rotordynamic behavior predicted by the simulation studies. A strategy for reducing synchronous shaft vibration through appropriate design of coupled shaft/bearing/housing vibration modes is identified. The results are presented and discussed.

  2. Synchronous dynamics of a coupled shaft/bearing/housing system with auxiliary support from a clearance bearing: Analysis and experiment

    NASA Technical Reports Server (NTRS)

    Lawen, James L., Jr.; Flowers, George T.

    1995-01-01

    This study examines the response of a flexible rotor supported by load sharing between linear bearings and an auxiliary clearance bearing. The objective is to develop a better understanding of the dynamical behavior of a magnetic bearing supported rotor system interacting with auxiliary bearings during a critical operating condition. Of particular interest is the effect of coupling between the bearing/housing and shaft vibration on the rotordynamical responses. A simulation model is developed and a number of studies are performed for various parametric configurations. An experimental investigation is also conducted to compare and verify the rotordynamic behavior predicted by the simulation studies. A strategy for reducing synchronous shaft vibration through appropriate design of coupled shaft/bearing/housing vibration modes is identified.

  3. A study of the influence of bearing clearance on lateral coupled shaft/disk rotordynamics

    NASA Astrophysics Data System (ADS)

    Flowers, George T.; Wu, Fang S.

    1992-06-01

    This study examines the influence of bearing clearance on the dynamical behavior of a rotating, flexible disk/shaft system. Most previous work in nonlinear rotordynamics has tended to concentrate separately on shaft vibration or on bladed disk vibration, neglecting the coupling dynamics between them. The current work examines the important rotordynamical behavior of coupled disk/shaft dynamics. A simplified nonlinear model is developed for lateral vibration of a rotor system with a bearing clearance nonlinearity. The steady-state dynamical behavior of this system is explored using numerical simulation and limit cycle analysis. It is demonstrated that bearing clearance effects can produce superharmonic vibration that may serve to excite high amplitude disk vibration. Such vibration could lead to significantly increased bearing loads and catastrophic failure of blades and disks. In addition, multi-valued responses and aperiodic behavior was observed.

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

    SciTech Connect

    Keller, Jonathan; Guo, Yi

    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.

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

    SciTech Connect

    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.

  6. Method for Providing a Jewel Bearing for Supporting a Pump Rotor Shaft

    NASA Technical Reports Server (NTRS)

    Aber, Gregory S. (Inventor)

    2001-01-01

    Methods for a blood pump bearing system within a pump housing to support long-term high-speed rotation of a rotor with an impeller blade having a plurality of individual magnets disposed thereon to provide a small radial air gap between the magnets and a stator of less than 0.025 inches. The bearing system may be mounted within a flow straightener, diffuser, or other pump element to support the shaft of a pump rotor. The bearing system includes a zirconia shaft having a radiused end. The radiused end has a first radius selected to be about three times greater than the radius of the zirconia shaft. The radiused end of the zirconia shaft engages a flat sapphire endstone. Due to the relative hardness of these materials a flat is quickly produced during break-in on the zirconia radiused end of precisely the size necessary to support thrust loads whereupon wear substantially ceases. Due to the selection of the first radius, the change in shaft end-play during pump break-in is limited to a total desired end-play of less than about 0.010 inches. Radial loads are supported by an olive hole ring jewel that makes near line contact around the circumference of the shaft to support high speed rotation with little friction. The width of olive hole ring jewel is small to allow heat to conduct through to thereby prevent heat build-up in the bearing. A void defined by the bearing elements may fill with blood that then coagulates within the void. The coagulated blood is then conformed to the shape of the bearing surfaces.

  7. Roller to separator contact forces and cage to shaft speed ratios in roller bearings

    NASA Technical Reports Server (NTRS)

    Nypan, L. J.

    1978-01-01

    Cage to roller force measurements, cage to shaft speed ratios are reported for 115- and 118-mm bore roller bearings operating at speeds of 4000, 8000, and 12,000 rpm under loads ranging from 360 to 6670 N (80 to 1500 lb).

  8. Mitigation of Micropitting in Wind Turbine Main Shaft Bearings

    SciTech Connect

    Sethuraman, Latha; Guo, Yi; Sheng, Shuangwen

    2015-09-03

    In recent years, increasing evidence of failures has been reported from spherical roller main bearings used in three-point mounting (TPM) drivetrains of wind turbines. One of the leading causes has been micropitting, a failure mode that is possibly overlooked by design, selection and life-prediction tools. It remains to be seen if retrofitting problematic spherical roller bearings (SRBs) with improved bearing design solutions can improve their durability. Questions to ask might be: ‘Are the operating conditions of the main bearing well understood?’ and ‘Are the failures caused by deficient design practice or other unidentified external sources within the system?’ These questions fundamentally challenge the underlying design basis and encourage the need for a system analysis approach that is currently being undertaken by researchers from the National Renewable Energy Laboratory (NREL). Specifically, this article discusses a few potential design alternatives and system-level reassessment to circumvent micropitting in main bearings used in TPM drivetrains.

  9. Estimation of stiffening effect of shaft and housing material outside projected area of a rolling element bearing

    NASA Technical Reports Server (NTRS)

    Taylor, C. M.

    1977-01-01

    In the analysis of distortions occurring in rolling-element bearings, it is common to neglect the stiffening effect of shafting outside the bearing region. The magnitude of such an effect will be dependent primarily on the bearing width-to-bore ratio, the shaft geometry, and the location of the bearing on the shaft. An estimate is given of the stiffening effect for a wide range of these variables. In addition, brief consideration is given to the parallel situation existing at the outer ring housing.

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

    SciTech Connect

    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.

  11. Detail of exciter turbine showing shaft, scroll case, servomotor and ...

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

    Detail of exciter turbine showing shaft, scroll case, servo-motor and operating ring (left foreground) and hand wheel for butterfly valve (right background) - Morony Hydroelectric Facility, Dam and Powerhouse, Morony Dam Road, Great Falls, Cascade County, MT

  12. Transmission with two parallel driving shafts bearing two driving gears each meshed with same driven gear on parallel driven shaft

    SciTech Connect

    Akashi, T.; Ito, H.; Yamada, S.

    1986-06-17

    A transmission mechanism for a vehicle is described for receiving input of rotational power from a power supply member which rotates in a particular rotational direction and for outputting rotational power to a power receiving member which includes: an input member connected to the power supply member and which is rotatably mounted and receives supplying of the rotational power from the power supply member; a first driving gear wheel shaft; a second driving gear wheel shaft mounted generally parallel to the first driving gear wheel shaft; a driven gear wheel shaft mounted generally parallel to the first and second driving gear wheel shafts, the driven gear wheel shaft being rotationally connected to the power receiving member; a first driven gear wheel fixedly mounted on the driven gear wheel shaft; a first driving gear wheel which is rotatably mounted on the first driving gear wheel shaft and is constant mesh with the driven gear wheel, the first driving and driven gear wheels providing a first reduction gear ratio from the first driving gear wheel shaft to the driven gear wheel shaft; a second driven gear wheel fixedly mounted on the driven gear wheel shaft; a second driving gear wheel which is rotatably mounted on the second driving gear wheel shaft and is in constant mesh with the first driven gear wheel, the second driving and the first driven gear wheels providing a second reduction gear ratio smaller than the first reduction gear ratio from the second driving gear wheel shaft to the driven gear wheel shaft; a third driving gear wheel which is rotatably mounted on the first driving gear wheel shaft and is in constant mesh with the second driven gear wheel, the third driving and the second driven gear wheels providing a third reduction gear ratio smaller than the second reduction gear ratio from the first driving gear wheel shaft to the driven gear wheel shaft.

  13. Full Dynamic Reactions in the Basic Shaft Bearings of Big Band Saw Machines

    NASA Astrophysics Data System (ADS)

    Marinov, Boycho

    2013-03-01

    The band saws machines are a certain class woodworking machines for longitudinal or transversal cutting as well as for curvilinear wood cutting. These machines saw the wood through a band-saw blade and two feeding wheels. These wheels usually are very large and they are produced with inaccuracies. The centre of mass of the disc is displaced from the axis of rotation of the distance e (eccentricity) and the axis of the disk makes an angle with the axis of rotation. In this paper, the dy- namic reactions in the bearings of the basic shaft, which drives the band saw machines, are analyzed. These reactions are caused by the external loading and the kinematics and the mass characteristics of the rotating disk. The expressions for the full dynamic reactions are obtained. These expressions allow the parameters of the machines to be chosen in such a way that the loading in the shaft and the bearings to be minimal.

  14. Disk/Shaft Vibration Induced by Bearing Clearance Effects: Analysis and Experiment

    NASA Technical Reports Server (NTRS)

    Flowers, George T.; Wu, Fangsheng

    1996-01-01

    This study presents an investigation of the dynamics of a rotor system with bearing clearance. Of particular interest is the influence of such effects on coupled disk/shaft vibration. Experimental results for a rotor system with a flexible disk are presented and compared to predictions from a simulation model. Some insights and conclusions are obtained with regard to the conditions under which such vibration may be significant.

  15. Disk/Shaft Vibration Induced by Bearing Clearance Effects: Analysis and Experiment

    NASA Technical Reports Server (NTRS)

    Flowers, George T.; Wu, Fangsheng

    1996-01-01

    This study presents an investigation of the dynamics of a rotor system with bearing clearance. Of particular interest is the influence of such effects on coupled disk/shaft vibration. Experimental results for a rotor system with a flexible disk are presented and compared to predictions from a simulation model. Some insights and conclusions are obtained with regard to the conditions under which such vibration may be significant.

  16. Thermal shaft effects on load-carrying capacity of a fully coupled, variable-properties cryogenic journal bearing

    NASA Technical Reports Server (NTRS)

    Braun, M. J.; Wheeler, R. L., III; Hendricks, R. C.

    1986-01-01

    The purpose of this work was to perform a rather complete analysis for a cryogenic (oxygen) journal bearing. The Reynolds equation required coupling and simultaneous solution with the fluid energy equation. To correctly account for the changes in the fluid viscosity, the fluid energy equation was coupled with the shaft and bearing heat conduction energy equations. The effects of pressure and temperature on the density, viscosity, and load-carrying capacity were further discussed as analysis parameters, with respect to relative eccentricity and the angular velocity. The isothermal fluid case and the adiabatic fluid case represented the limiting boundaries. The discussion was further extrapolated to study the Sommerfeld number dependency on the fluid Nusselt number and its consequence on possible total loss of load-carrying capacity and/or seizure (catastrophic failure).

  17. Thermal shaft effects on load-carrying capacity of a fully coupled, variable-properties cryogenic journal bearing

    NASA Technical Reports Server (NTRS)

    Braun, M. J.; Wheeler, R. L., III; Hendricks, R. C.

    1986-01-01

    The purpose of this work was to perform a rather complete analysis for a cryogenic (oxygen) journal bearing. The Reynolds equation required coupling and simultaneous solution with the fluid energy equation. To correctly account for the changes in the fluid viscosity, the fluid energy equation was coupled with the shaft and bearing heat conduction energy equations. The effects of pressure and temperature on the density, viscosity, and load-carrying capacity were further discussed as analysis parameters, with respect to relative eccentricity and the angular velocity. The isothermal fluid case and the adiabatic fluid case represented the limiting boundaries. The discussion was further extrapolated to study the Sommerfeld number dependency on the fluid Nusselt number and its consequence on possible total loss of load-carrying capacity and/or seizure (catastrophic failure).

  18. Longitudinal femoral shaft due to bone insufficiency. A review of three cases.

    PubMed

    Maraval, Anne; Grados, Franck; Royant, Valérie; Damade, Richard; Boulu, Gilles; Fardellone, Patrice

    2003-12-01

    We report three new cases of longitudinal femoral shaft fracture due to bone insufficiency and review the eight cases reported in the literature. The typical patient is a woman older than 65 years of age who present with mechanical pain in the thigh and/or groin. Palpation of the thigh may reproduce the pain. The diagnosis is often made late because the radiographs are normal initially. However, an early and consistent finding is increased radionuclide uptake along the femoral shaft. The fracture line is readily evidenced by computed tomography but may be difficult to see on magnetic resonance imaging. Use of crutches for 6 weeks to protect the bone from weight bearing ensures healing of the fracture.

  19. Prediction of maximum unbalance responses of a gear-coupled two-shaft rotor-bearing system

    NASA Astrophysics Data System (ADS)

    Lee, An Sung; Ha, Jin Woong

    2005-05-01

    A general method was presented for obtaining the unbalance response orbit of a gear-coupled two-shaft rotor-bearing system, based on the finite element approach. Specifically, analytical solutions of the maximum and minimum radii of the orbit were proposed. The method was applied to the unbalance response analysis of a 600 kW turbo-chiller rotor-bearing system, having a bull-pinion speed increasing gear. Bumps in the unbalance responses were observed at the first torsional natural frequency because of the coupling between the lateral and torsional dynamics due to gear meshing. In addition, the analytical solutions were validated with results obtained by a full numerical approach. The proposed method can be generally applied to an analysis of the unbalance response orbits of dual-shaft rotor-bearing systems coupled by bearings as well, which are often found in aerospace gas turbine engines.

  20. A non-linear mathematical model for dynamic analysis of spur gears including shaft and bearing dynamics

    NASA Astrophysics Data System (ADS)

    Özgüven, H. N.

    1991-03-01

    A six-degree-of-freedom non-linear semi-definite model with time varying mesh stiffness has been developed for the dynamic analysis of spur gears. The model includes a spur gear pair, two shafts, two inertias representing load and prime mover, and bearings. As the shaft and bearing dynamics have also been considered in the model, the effect of lateral-torsional vibration coupling on the dynamics of gears can be studied. In the non-linear model developed several factors such as time varying mesh stiffness and damping, separation of teeth, backlash, single- and double-sided impacts, various gear errors and profile modifications have been considered. The dynamic response to internal excitation has been calculated by using the "static transmission error method" developed. The software prepared (DYTEM) employs the digital simulation technique for the solution, and is capable of calculating dynamic tooth and mesh forces, dynamic factors for pinion and gear, dynamic transmission error, dynamic bearing forces and torsions of shafts. Numerical examples are given in order to demonstrate the effect of shaft and bearing dynamics on gear dynamics.

  1. A non-linear mathematical model for dynamic analysis of spur gears including shaft and bearing dynamics

    NASA Technical Reports Server (NTRS)

    Ozguven, H. Nevzat

    1991-01-01

    A six-degree-of-freedom nonlinear semi-definite model with time varying mesh stiffness has been developed for the dynamic analysis of spur gears. The model includes a spur gear pair, two shafts, two inertias representing load and prime mover, and bearings. As the shaft and bearing dynamics have also been considered in the model, the effect of lateral-torsional vibration coupling on the dynamics of gears can be studied. In the nonlinear model developed several factors such as time varying mesh stiffness and damping, separation of teeth, backlash, single- and double-sided impacts, various gear errors and profile modifications have been considered. The dynamic response to internal excitation has been calculated by using the 'static transmission error method' developed. The software prepared (DYTEM) employs the digital simulation technique for the solution, and is capable of calculating dynamic tooth and mesh forces, dynamic factors for pinion and gear, dynamic transmission error, dynamic bearing forces and torsions of shafts. Numerical examples are given in order to demonstrate the effect of shaft and bearing dynamics on gear dynamics.

  2. Performance of an electromagnetic bearing for the vibration control of a supercritical shaft

    NASA Technical Reports Server (NTRS)

    Bradfield, C. D.; Roberts, J. B.; Karunendiran, R.

    1987-01-01

    The flexural vibrations of a rotating shaft, running through one or more critical speeds, can be reduced to an acceptably low level by applying suitable control forces at an intermediate span position. If electromagnets are used to produce the control forces then it is possible to implement a wide variety of control strategies. A test rig is described which includes a microprocessor-based controller, in which such strategies can be realised in terms of software-based algorithms. The electromagnet configuration and the method of stabilising the electromagnet force-gap characteristic are discussed. The bounds on the performance of the system are defined. A simple control algorithm is outlined, where the control forces are proportional to the measured displacement and velocity at a single point on the shaft span; in this case the electromagnet behaves in a similar manner to that of a parallel combination of a linear spring and damper. Experimental and predicted performance of the system are compared, for this type of control, where various programmable rates of damping are applied.

  3. Performance of large-bore tapered-roller bearings under combined radial and thrust load at shaft speeds to 15,000 rpm

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Signer, H. R.

    1977-01-01

    The performance of 120.65-mm bore tapered roller bearings was investigated at shaft speeds up to 15,000 rpm. Temperature distribution and bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rate, and lubricant inlet temperature. Lubricant was supplied by either jets or by a combination of holes through the cone directly to the cone-rib contact and jets at the roller small-end side. Cone-rib lubrication significantly improved high-speed tapered-roller bearing performance, yielding lower cone-face temperatures and lower power loss and allowing lower lubricant flow rates for a given speed condition. Bearing temperatures increased with increased shaft speed and decreased with increased lubricant flow rate. Bearing power loss increased with increased shaft speed and increased lubricant flow rate.

  4. Study of rolling element dynamic interactions with separators and raceway paths: Roller to separator contact forces and cage to shaft speed ratios in roller bearings

    NASA Technical Reports Server (NTRS)

    Nypan, L. J.

    1978-01-01

    Cage to roller force measurements, cage to shaft forces, and cage to shaft speed ratios are reported for 115 and 118mm bore roller bearings operating at speeds of 4,000, 8,000, and 12,000 rpm under loads ranging from 360 to 6670 N (80 to 1500 lb).

  5. [Atipic osteosarcoma in the femoral shaft case report and review of the literature].

    PubMed

    Clara-Altamirano, M A; García-Ortega, D Y; Martínez-Tlahuel, J L; Martínez-Said, H; Caro-Sánchez, C H S; García-Ruíz, G C; Mejía-Salazar, C R; Cuellar-Hubbe, M

    2016-01-01

    Osteosarcoma is the most frequent primary malignant bone tumor. It is characterized by osteoid production by tumor cells. Its most frequent location is in the metaphyses of long bones, but a purely diaphyseal presentation is reported in 10% of cases. We report the case of a female 25 year-old patient whose symptoms of pain and swelling of the right mid thigh started four months before, without an apparent cause. Femur X-rays showed a tumor in the femoral shaft. The MRI showed extension to soft tissues with no compromise of the neurovascular bundle. The histopathologic report of the incisional biopsy was osteoblastic and chondroblastic osteosarcoma, classified as Enneking IIB, AJCC IIB. Treatment consisted of three cycles of neoadjuvant chemotherapy. Then intercalary femur resection plus reconstruction with centromedullary nailing and a diaphyseal spacer were performed. The histopathologic report was 95% necrosis (Huvos grade III). Three cycles of adjuvant chemotherapy were given and now, 18 months after completing the latter, the patient has no signs of local or distant tumor activity, and she can walk unassisted. Despite the fact that osteosarcoma does not occur usually in the mid shaft of long bones, we should always bear it in mind as part of the differential diagnosis for other conditions that occur more frequently in that region. Such location allows for a broad gamut of surgical approaches that spare the adjacent joints.

  6. Shaft balancing

    DOEpatents

    Irwin, John A.

    1979-01-01

    A gas turbine engine has an internal drive shaft including one end connected to a driven load and an opposite end connected to a turbine wheel and wherein the shaft has an in situ adjustable balance system near the critical center of a bearing span for the shaft including two 360.degree. rings piloted on the outer diameter of the shaft at a point accessible through an internal engine panel; each of the rings has a small amount of material removed from its periphery whereby both of the rings are precisely unbalanced an equivalent amount; the rings are locked circumferentially together by radial serrations thereon; numbered tangs on the outside diameter of each ring identify the circumferential location of unbalance once the rings are locked together; an aft ring of the pair of rings has a spline on its inside diameter that mates with a like spline on the shaft to lock the entire assembly together.

  7. Research report: User's manual for computer program AT81y003 SHABERTH. Steady state and transient thermal analysis of a shaft bearing system including ball, cylindrical and tapered roller bearings

    NASA Technical Reports Server (NTRS)

    Hadden, G. B.; Kleckner, R. J.; Ragen, M. A.; Sheynin, L.

    1981-01-01

    The SHABERTH program is capable of simulating the thermomechanical performance of a load support system consisting of a flexible shaft supported by up to five rolling element bearings. Any combination of ball, cylindrical, and tapered roller bearings can be used to support the shaft. The user can select models in calculating lubricant film thickness and traction forces. The formulation of the cage pocket/rolling element interaction model was revised to improve solution numerical convergence characteristics.

  8. Shaft-Rotation Detector

    NASA Technical Reports Server (NTRS)

    Randall, Richard L.

    1990-01-01

    Signal-processing subsystem generates signal indicative of rotation of shaft from output of accelerometer mounted on housing of bearing supporting shaft. Output of subsystem binary signal at frequency of rotation of shaft. Part of assembly of electronic equipment measuring vibrations in rotating machinery. Accelerometer mounted in such way sensitive to vibrations of shaft perpendicular to axis. Output of accelerometer includes noise and components of vibration at frequencies higher than rotational frequency of shaft.

  9. Limit cycles of a flexible shaft with hydrodynamic journal bearings in unstable regimes

    NASA Technical Reports Server (NTRS)

    Brown, R. D.; Black, H. F.

    1980-01-01

    A symmetric 3 mass rotor supported on hydrodynamic bearings is described. An approximate method of representing finite bearings is used to calculate bearing forces. As the method sums forces from a number of independent circular lobes lemon 3 and 4 lobe bearings are taken into account. The calculations are based on an axial groove bearing. Linear analysis precedes nonlinear simulation of some unstable conditions. The demonstration of small limit cycles suggests that necessarily flexible rotors e.g., helicopter tail rotors, may be practical without either tilt pad bearings or external dampers.

  10. Study of a misaligned flexibly coupled shaft system having nonlinear bearings and cyclic coupling stiffness—Theoretical model and analysis

    NASA Astrophysics Data System (ADS)

    Redmond, I.

    2010-03-01

    A model which enables dynamic analysis of flexibly coupled misaligned shafts is presented. The model is setup to account for both angular and parallel misalignment in the presence of mass unbalance and incorporates a coupling having angular, torsional and axial flexibility. Among the important features is the ability to simulate both nonlinear bearing stiffness and coupling angular-stiffness anisotropy. The equations of motion are derived for the linear system, extended to include nonlinear bearing effects and subsequently transformed into non-dimensional form for general application. A series of numerical analyses are performed and the influence of important system parameters assessed thereby providing insight to the resulting static and dynamic forces and motions. Angular and parallel misalignments are shown to produce fundamentally different system response. It is found that the static preload induced by both types of misalignment can play a key role in producing complex vibration resulting from it's interaction with rotating-element anisotropy and bearing nonlinear properties. Bearing static forces are altered and rotating elements are subjected to alternating forces which could affect fatigue life. Bearing forces can be further modified by the application of transmitted torque. The potential for great variability in system response is shown to exist due to the participation of numerous influential variables.

  11. Design of electromagnetic bearing for vibration control of flexible transmission shaft

    NASA Technical Reports Server (NTRS)

    Gondhalekar, V.; Holmes, R.

    1984-01-01

    Recently magnetic bearings were proposed by several researchers and shown to be viable on a variety of rotor assemblies. The design and construction of such a bearing, which employs features hitherto not used by other workers is examined. These include an original approach to the design of the electromagnets and their amplifiers, and to software in a digital control system, to condition the control signals so as to make the magnets appear to be linear and uncoupled. The resulting system is used to control a rotor-bearing assembly, whose speed range covers two flexural-critical speeds.

  12. Stress analysis of bearings of main eccentric shaft for width mill

    NASA Astrophysics Data System (ADS)

    Feng, Xianzhang; Liu, Yuanpeng; Cui, Yanmei; Jiang, Zhiqiang

    2009-07-01

    In order to analyze the dynamic load and lifespan of bearing of maim eccentric axis of mill in the course of working, the mechanical model of maim eccentric axis was established using the theory of free beam in material mechanics under the research load character of metal rolling, make the results of the finite element analysis as conditions for the model during rolling metal. The force and lifespan calculation were studied for the bearing systematically, the calculated results show that the bearings exist periodicity force of impact, the same rules as testing inline. The calculated results coincide better with practical measured results and completely achieve the prediction accuracy requirements required by the engineering, and the bearings can meet requirements in the field.

  13. Predictive analysis of shaft station radon concentrations in underground uranium mine: A case study.

    PubMed

    Zhao, Guoyan; Hong, Changshou; Li, Xiangyang; Lin, Chunping; Hu, Penghua

    2016-07-01

    This paper presented a method for predicting shaft station radon concentrations in a uranium mine of China through theoretical analysis, mathematical derivation and Monte-Carlo simulation. Based upon the queuing model for tramcars, the average waiting time of tramcars and average number of waiting tramcars were determined, which were further used in developing the predictive model for calculating shaft station radon concentrations. The results exhibit that the extent of variation of shaft station radon concentration in the case study mine is not significantly affected by the queuing process of tramcars, and is always within the allowable limit of 200 Bq m(-3). Thus, the empirical limit of 100,000 T annual ore-hoisting yields has no value in ensuring radiation safety for this mine. Moreover, the developed model has been validated and proved useful in assessing shaft station radon levels for any uranium mine with similar situations.

  14. Case history of magnetic bearing supported hot gas turboexpander

    SciTech Connect

    Destombes, Y.; Allaire, P.E.

    1995-12-31

    A very significant advantage for the use of magnetic bearings in hot gas and cryogenic expanders is that the bearing operating temperature can be much higher or lower than for conventional oil lubricated fluid film or rolling element bearings. This has lead to the increasing development of industrial expanders which are magnetic bearing supported and rather complex bearing oil supply sealing arrangements can be eliminated. As advances in magnetic bearing technology and understanding occur, the design and performance of the magnetic bearings continues to improve. The purpose of this paper is to describe some characteristics of industrial magnetic bearing supported turboexpanders, both hot gas and cryogenic, and present a particular hot gas expander application. This paper discusses the basic principles of operation of the magnetic bearings including the bearing radial and thrust bearings, sensors, control system, and dynamic characteristics. The governing equations are given for upper quadrant radial bearing designs. Design equations relevant to bearing design will be presented to assist potential users of magnetic bearings in understanding their operation. The paper also presents a practical application of magnetic bearings to a hot gas turbogenerator. The bearings support a turbine wheel which converts the exhaust gas energy of a blast furnace into electrical power through a synchronous 6 MW generator. The magnetic bearing allowed the rotor to be constructed as a single shaft machine. The turbine wheel is directly connected to the generator rotor. The unit has been successfully operated for a 8 year period and now has in excess of 70,000 hours in a steel plant in Europe. It has some unique features: (1) it is the heaviest magnetic bearing supported rotor in industrial operation at 8 tons, (2) it has very high unbalance acceptance, (3) it has a special rotor mounted auxiliary bearing design, and (4) only the upper quadrant of the bearing is employed in the unit.

  15. Bearing system

    DOEpatents

    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.

  16. Arrow shaft injury of the wrist and hand: case report, management, and surgical technique.

    PubMed

    Launikitis, Robert A; Viegas, Steven F

    2009-01-01

    A case of accidental, self-inflicted injury to the hand from a hollow carbon shaft arrow which broke in its midshaft while attempting to shoot the arrow from a compound bow is presented. Basic knowledge of low velocity gunshot wounds and arrow injuries was applied in the treatment of this injury along with a unique management technique. The outcome, including hand function was good without any functional loss.

  17. Crank shaft support assembly

    DOEpatents

    Natkin, Robert J.; Oltmans, Bret; Allison, John E.; Heater, Thomas J.; Hines, Joy Adair; Tappen, Grant K.; Peiskammer, Dietmar

    2007-10-23

    A crank shaft support assembly for increasing stiffness and reducing thermal mismatch distortion in a crank shaft bore of an engine comprising different materials. A cylinder block comprises a first material and at least two crank journal inserts are insert-molded into respective crank journal regions of the cylinder block and comprise a second material having greater stiffness and a lower thermal coefficient of expansion that the first material. At least two bearing caps are bolted to the respective crank journal inserts and define, along with the crank journal inserts, at least two crank shaft support rings defining a crank shaft bore coaxially aligned with a crank shaft axis. The bearing caps comprise a material having higher stiffness and a lower thermal coefficient of expansion than the first material and are supported on the respective crank journal inserts independently of any direct connection to the cylinder block.

  18. A very rare Presentation of Bifocal Non Union Radius with Ipsilateral Ulnar Shaft Non Union: Case Report

    PubMed Central

    Padha, Vikas; Awasthi, Bhanu; Singh, Dhananjay; Kalia, Sandeep

    2016-01-01

    Introduction: A bifocal non-union of shaft of radius associated with ipsilateral non-union shaft of ulna in an adult has not been reported in the literature till date to the best of our knowledge, though few similar cases of fresh fractures have been reported. The case being reported by us is the first of its kind. Case Presentation: We report a case of bifocal non-union of shaft radius with non-union ipsilateral shaft of ulna in a 48-year-old right handed male along with discussion of alternative treatment options. Conclusion: We describe an extremely rare and complicated non-union in which our patient got excellent results along with satisfactory functional recovery as a result of appropriate surgical treatment. PMID:27299137

  19. Subbrachial approach to humeral shaft fractures: new surgical technique and retrospective case series study

    PubMed Central

    Boschi, Vladimir; Pogorelic, Zenon; Gulan, Gordan; Vilovic, Katarina; Stalekar, Hrvoje; Bilan, Kanito; Grandic, Leo

    2013-01-01

    Background There are few surgical approaches for treating humeral shaft fractures. Here we present our results using a subbrachial approach. Methods We conducted a retrospective case series involving patients who had surgery for a humeral shaft fracture between January 1994 and January 2008. We divided patients into 4 groups based on the surgical approach (anterior, anterolateral, posterior, subbrachial). In all patients, an AO 4.5 mm dynamic compression plate was used. Results During our study period, 280 patients aged 30–36 years underwent surgery for a humeral shaft fracture. The average duration of surgery was shortest using the subbrachial approach (40 min). The average loss of muscle strength was 40% for the anterolateral, 48% for the posterior, 42% for the anterior and 20% for the subbrachial approaches. The average loss of tension in the brachialis muscle after 4 months was 61% for the anterolateral, 48% for the anterior and 11% for the subbrachial approaches. Sixteen patients in the anterolateral and anterior groups and 6 patients in the posterior group experienced intraoperative lesions of the radial nerve. No postoperative complications were observed in the subbrachial group. Conclusion The subbrachial approach is practical and effective. The average duration of the surgery is shortened by half, loss of the muscle strength is minimal, and patients can resume everyday activities within 4 months. No patients in the sub-brachial group experienced injuries to the radial or musculocutaneous nerves. PMID:23187037

  20. A journal bearing with variable geometry for the suppression of vibrations in rotating shafts: Simulation, design, construction and experiment

    NASA Astrophysics Data System (ADS)

    Chasalevris, Athanasios; Dohnal, Fadi

    2015-02-01

    The idea for a journal bearing with variable geometry was formerly developed and investigated on its principles of operation giving very optimistic theoretical results for the vibration quenching of simple and more complicated rotor bearing systems during the passage through the first critical speed. The journal bearing with variable geometry is presented in this paper in its final form with the detailed design procedure. The current journal bearing was constructed in order to be applied in a simple real rotor bearing system that already exists as an experimental facility. The current paper presents details on the manufactured prototype bearing as an experimental continuation of previous works that presented the simulation of the operating principle of this journal bearing. The design parameters are discussed thoroughly under the numerical simulation for the fluid film pressure in dependency of the variable fluid film thickness during the operation conditions. The implementation of the variable geometry bearing in an experimental rotor bearing system is outlined. Various measurements highlight the efficiency of the proposed bearing element in vibration quenching during the passage through resonance. The inspiration for the current idea is based on the fact that the alteration of the fluid film characteristics of stiffness and damping during the passage through resonance results in vibration quenching. This alteration of the bearing characteristics is achieved by the introduction of an additional fluid film thickness using the passive displacement of the lower half-bearing part. • The contribution of the current journal bearing in vibration quenching. • Experimental evidence for the VGJB contribution.

  1. Ipsilateral Fracture Shaft Femur with Neglected Dislocation of Prosthesis: A Case Report.

    PubMed

    Jain, Mantu; Bihari, Amar Jyoti; Sriramka, Bhavna

    2013-01-01

    Neglected hip dislocation is rare in today's world and after prosthesis replacement even rarer finding. However such patients may not report to surgeons until they develop secondary complications. Management of such patient's is a challenge to the treating surgeon and need to be tailored suiting to patient's demands, expectations and constraints of financial resources. We did not find a similar case in the electronic and print media and therefore report this case which was innovatively managed. A 60 year farmer presented with fracture shaft femur and ipsilateral dislocation prosthesis of right hip. He had a hemiarthroplasty done for fracture neck of femur in the past but used to walk with a lurch since he started to ambulate after discharge. However he was satisfied despite "some problems" which had caused shortening of his limb. The patient was informed of the various treatment options and their possible complications. He expressed his inability to afford a Total Hip Arthroplasty (THA) at any stage and consented for other options discussed with him. The patient was positioned supine and adductor tenotomy done. Next he was positioned laterally and the fracture was fixed with heavy duty broad dynamic compression plate and screws. The wound was temporarily closed. Now through the previous scar via posterior approach the hip was exposed. The prosthesis was found to be firmly fixed to the proximal femur. The acetabulum was cleared with fibrous tissue. All attempts the prosthesis to relocate the prosthesis failed after several attempts and it was best decided to leave alone. Post operatively period was uneventful. At follow up he refused for any further manoeuvre in future inform of heavy traction and attempts to reduce the same. At one year when he was walking unaided and his X-rays showed that fracture had well united his SF-36 score was PCS - 49.6 and MCS - 51.9. Ipsilateral shaft femur fracture in chronically dislocated prosthesis, done for fracture neck of femur is

  2. Oxford phase III meniscal bearing fracture: case report.

    PubMed

    Lim, Hong-Chul; Shon, Won-Yong; Kim, Seung-Ju; Bae, Ji-Hoon

    2014-01-01

    Meniscal bearing fracture is a rare complication of phase III Oxford unicompartmental knee replacement (UKR). We report a case of a meniscal bearing fracture that occurred 7 years after phase III Oxford medial UKR. The meniscal bearing showed uneven delamination of the polyethylene in the thinnest articular surface and an impingement lesion. This lesion initiated a fatigue crack that propagated to cause failure of the meniscal bearing. This is the first report of a meniscal bearing fracture without a posterior marker wire.

  3. CASE REPORT AND LITERATURE REVIEW ANTERIOR SHOULDER DISLOCATION WITH THREE-PART PROXIMAL HUMERUS FRACTURE AND HUMERAL SHAFT FRACTURE

    PubMed Central

    Flint, John H.; Carlyle, Laura M.; Christiansen, Cory C.; Nepola, James V.

    2009-01-01

    Dislocation of the shoulder and proximal humerus fracture with coexistent humeral shaft fracture is a rare injury reported in literature. There have been a total of 20 cases reported in the literature since 19401-13 (see Table 1). These injuries often occur as a result of high velocity trauma and most have been treated, at least partially, with invasive or operative management. We present the case of a woman with an anterior dislocation, three-part proximal humerus fracture and concomitant humerus shaft fracture and discuss her non-invasive treatment. PMID:19742096

  4. Application of rapid computer modeling in the analysis of the stabilization method in intraoperative femoral bone shaft fracture during revision hip arthroplasty - a case report.

    PubMed

    Lorkowski, Jacek; Mrzygłód, Mirosław M; Kotela, Andrzej; Kotela, Ireneusz

    2014-08-15

    Fractures of the femoral bone shaft during and after hip arthroplasty are a serious clinical problem. The paper presents the use of rapid computer modeling FEM 2D to optimize the stabilization of femoral shaft fracture in case of hip revision arthroplasty. Using the FEM modeling may be helpful for planning and assessment of orthopaedic treatment in similar cases.

  5. Repairing A Shaft Prone To Fatigue

    NASA Technical Reports Server (NTRS)

    Sharp, Roger A.; Larsen, David V.; Bates, Garold A.

    1991-01-01

    Shaft of hydraulic motor now outlives its bearings. Procedure for repairing John Deere Series 50 (or equivalent) hydraulic motor solves problem posed by common type of fatigue failure of shaft. Includes forming internally threaded hole in end of shaft, inserting double-threaded end stud, and adding washers and collars.

  6. Two gimbal bearing case studies: Some lessons learned

    NASA Technical Reports Server (NTRS)

    Loewenthal, Stuart H.

    1988-01-01

    Two troublesome, torque related problems associated with gimbal actuators are discussed. Large, thin section angular contact bearings can have a surprisingly high torque sensitivity to radial thermal gradients. A predictive thermal-mechanical bearing analysis, as described, was helpful in establishing a safe temperature operating envelope. In the second example, end-of-travel torque limits of an oscillatory gimbal bearing appoached motor stall during limit cycling life tests. Bearing modifications required to restore acceptable torque performance are described. The lessons learned from these case studies should benefit designers of precision gimbals where singular bearing torque related problems are not uncommon.

  7. Shaft adjuster

    DOEpatents

    Harry, H.H.

    1988-03-11

    Abstract and method for the adjustment and alignment of shafts in high power devices. A plurality of adjacent rotatable angled cylinders are positioned between a base and the shaft to be aligned which when rotated introduce an axial offset. The apparatus is electrically conductive and constructed of a structurally rigid material. The angled cylinders allow the shaft such as the center conductor in a pulse line machine to be offset in any desired alignment position within the range of the apparatus. 3 figs.

  8. Shaft adjuster

    DOEpatents

    Harry, Herbert H.

    1989-01-01

    Apparatus and method for the adjustment and alignment of shafts in high power devices. A plurality of adjacent rotatable angled cylinders are positioned between a base and the shaft to be aligned which when rotated introduce an axial offset. The apparatus is electrically conductive and constructed of a structurally rigid material. The angled cylinders allow the shaft such as the center conductor in a pulse line machine to be offset in any desired alignment position within the range of the apparatus.

  9. Treatment of the femoral shaft nonunion with double plate fixation and bone grafting: A case series of 14 patients.

    PubMed

    Maimaitiyiming, Asihaerjiang; Amat, Abdusami; Rehei, Aili; Tusongjiang, Mamatkeremula; Li, Cao

    2015-01-01

    The management of femoral shaft nonunion still remains a challenge in orthopaedic surgery. It represents a serious postoperative problem for the patient, associated with plate breakage and loosening, bone defect, shortening deformity and infection. A double plate fixation combined with bone grafting may become a promising therapeutic strategy for the treatment of patients with femoral shaft nonunion. In this study, our goal was to evaluate the clinical outcome of a novel approach for 14 consecutive patients with femoral shaft nonunion using double plate fixation with bone grafting. Retrospective data from June 2010 to August 2012 were obtained from records for 14 consecutive femoral shaft aseptic nonunion patients treated with double plate fixation combined with bone grafting. Nine patients were men and five patients were woman and average age of the patients was 26 years (range from 22 to 32 years). The mean time since injury was 26.2 months. The nonunion had resulted from repeated internal fixation failure (including plate or intramedullary nail fixation) in nine cases and primary internal fixation in five cases. All the 14 patients were followed up for an average of 14.8 (10-25) months. All cases achieved bony union without wound infection or fixation failure and the mean time to union was 5.2 months (range 4-7 months). Double plate fixation and bone grafting are a promising method for femoral shaft nonunion. In addition, this strategy is useful for such a nonunion caused by a repeated plate or intramedullary nail fixation failure with bone defect due to its strong stability with three-dimensional fixation and fully bone graft availability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Structure of cam shaft for engine

    SciTech Connect

    Sato, M.; Nakamizo, K.; Mitadera, T.

    1989-02-21

    This patent describes the structure of a cam shaft for an engine having a crankshaft provided with a helical crank gear and a cam shaft provided with a helical cam gear meshing with the crank gear and rotatably supported at both ends thereof by journal bearing boxes, characterized inn that either one of the journal bearing boxes is communicated with a pressure oil supply passage, thereby causing the oil pressure produced within the one journal bearing box to act upon the end face of the cam shaft so that the cam shaft is normally biased in a constant axial direction.

  11. Case-Match Controlled Comparison of Minimally Invasive Plate Osteosynthesis and Intramedullary Nailing for the Stabilization of Humeral Shaft Fractures.

    PubMed

    Davies, Gareth; Yeo, Gerald; Meta, Mahendrakumar; Miller, David; Hohmann, Erik; Tetsworth, Kevin

    2016-11-01

    To compare the risk of major complications after either minimally invasive plate osteosynthesis (MIPO) or intramedullary nailing (IMN) of humeral shaft fractures. Retrospective, case-match controlled study. A major metropolitan tertiary referral trauma center in Australia. Thirty patients with fractures of the humeral shaft. Either MIPO or IMN were performed on 15 patients each with traumatic humeral shaft fractures. The cumulative risk of 3 major complications associated with these procedures: nonunion, infection, and iatrogenic radial nerve injury. An overall major complication rate of 53% was observed in the patients treated with IMN; one complication (7%) was identified in those managed with humeral MIPO, a nonunion. Complications after IMN included 4 patients (27%) with nonunion, 3 patients (20%) with iatrogenic radial nerve injuries, and 1 patient (7%) with a wound infection. Statistical analysis revealed a significant between-group difference (P = 0.01) in the cumulative rate of major complications. When each of these complications was considered independently, no statistically significant difference was demonstrated. This study suggests that humeral MIPO results in a significantly lower pooled major complication rate than that of IMN, and it should therefore be considered an attractive alternative to IMN in those patients requiring surgical stabilization of a traumatic humeral shaft fracture. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

  12. GAS BEARING

    DOEpatents

    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.

  13. Centrifugally decoupling touchdown bearings

    DOEpatents

    Post, Richard F

    2014-06-24

    Centrifugally decoupling mechanical bearing systems provide thin tensioned metallic ribbons contained in a support structure. This assembly rotates around a stationary shaft being centered at low speeds by the action of the metal ribbons. Tension springs are connected on one end to the ribbons and on the other end to the support structure. The ribbons pass through slots in the inner ring of the support structure. The spring preloading thus insures contact (or near-contact) between the ribbons and the shaft at rotation speeds below the transition speed. Above this speed, however, the centrifugal force on the ribbons produces a tensile force on them that exceeds the spring tensile force so that the ribbons curve outward, effectively decoupling them from mechanical contact with the shaft. They still remain, however, in position to act as a touchdown bearing in case of abnormally high transverse accelerations.

  14. THRUST BEARING

    DOEpatents

    Heller, P.R.

    1958-09-16

    A thrust bearing suitable for use with a rotor or blower that is to rotate about a vertical axis is descrihed. A centrifagal jack is provided so thnt the device may opernte on one hearing at starting and lower speeds, and transfer the load to another bearing at higher speeds. A low viscosity fluid is used to lubricate the higher speed operation bearing, in connection with broad hearing -surfaces, the ability to withstand great loads, and a relatively high friction loss, as contraated to the lower speed operatio;n bearing which will withstand only light thrust loads but is sufficiently frictionfree to avoid bearing seizure during slow speed or startup operation. An axially aligned shaft pin provides the bearing surface for low rotational speeds, but at higher speed, weights operating against spring tension withdraw nthe shaft pin into the bearing proper and the rotor shaft comes in contact with the large bearing surfaces.

  15. [The effect of verticalization of the resulting force (R) of weight bearing in the hip joint on morphologic characteristics of the medullary canal in the femoral shaft in patients with coxarthrosis].

    PubMed

    Jovanović, S

    1992-01-01

    An influence of verticalization of the resulting force of weight-bearing on the hip joint "R" on the morphological characteristics of the medullar canal on the proximal edge of the shaft of femur was researched. Progressive degenerative changes of the hip joint with a consequent sideways limping or changes of the collodiaphysial angle (ccd angle) were the cause of the verticalization of the resulting force "R". The analysis of patients treated and operated on The Orthopaedic Department of the General Hospital Osijek and The Orthopaedic Clinic of The Medical Faculty of The University of Zagreb. The research, undoubtedly, proved that the patients with coxarthrosis and side-ways in the hip or with changed collodiaphysial angle experienced verticalization of the resulting force of weigh-bearing of the hip joint and the proximal edge of femur which caused morphological changes of the medular canal of the shaft of femur.

  16. 119. #3 SHAFT ALLEY AFT LOOKING FORWARD ON STARBOARD ...

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

    119. #3 SHAFT ALLEY - AFT LOOKING FORWARD ON STARBOARD SIDE SHOWING #3 SHAFT COUPLING WITH LOCKING DEVICE INSTALLED, SHAFT SPRING BEARING, SHAFT SEAL COOLING WATER LINE, FIVE INCH FIRE MAIN AND BALLASTING MANIFOLD. - U.S.S. HORNET, Puget Sound Naval Shipyard, Sinclair Inlet, Bremerton, Kitsap County, WA

  17. CUSHIONED BEARING

    DOEpatents

    Rushing, F.C.

    1960-09-01

    A vibration damping device effective to dampen vibrations occurring at the several critical speeds encountered in the operation of a high-speed centrifuge is described. A self-centering bearing mechanism is used to protect both the centrifuge shaft and the damping mechanism. The damping mechanism comprises spaced-apant, movable, and stationary sleeve members arranged concentrically of a rotating shaft with a fluid maintained between the members. The movable sleeve member is connected to the shaft for radial movement therewith.

  18. An unconventional indication of the Sauve' - Kapandji procedure in a radial shaft pseudoarthrosis and chronic DRUJ dislocation: a case report.

    PubMed

    Theodorakis, E; Fanelli, M; Ottolenghi, P; Pappalardo, S

    2013-01-01

    We present a 42-years-old male who developed a radial shaft pseudoartrosis and a chronic DRUJ dislocation/instability, following a Galeazzi fracture. He presented to our Office with a severe inability of wrist and forearm motion. A Sauve'-Kapandji procedure was adopted, performing a lateral approach to the ulna and grafting the excised ulnar block to retrieve radial length at the pseudoarthrosis level. Cancellous bone grafts from the iliac crest were also applied and mixed with autologous platelet rich plasma to promote callus formation. The goal was to create an intentional pseudoarthrosis of the distal ulna combined with a DRUJ arthrodesis, in order to resolve instability and regain forearm pronation/supination. We obtained bone healing, an excellent clinical recovery, and the patient returned to all his previous activities six months after surgery. To our knowledge, this is the first reported case of a radial shaft psudoarthrosis treated with the Sauve'-Kapandji technique.

  19. Wave Journal Bearings Under Dynamic Loads

    NASA Technical Reports Server (NTRS)

    Hendricks, Robert C.; Dimofte, Florin

    2002-01-01

    The dynamic behavior of the wave journal bearing was determined by running a three-wave bearing with an eccentrically mounted shaft. A transient analysis was developed and used to predict numerical data for the experimental cases. The three-wave journal bearing ran stably under dynamic loads with orbits well inside the bearing clearance. The orbits were almost circular and nearly free of the influence of, but dynamically dependent on, bearing wave shape. Experimental observations for both the absolute bearing-housing-center orbits and the relative bearing-housing-center-to-shaft-center orbits agreed well with the predictions. Moreover, the subsynchronous whirl motion generated by the fluid film was found experimentally and predicted theoretically for certain speeds.

  20. Integrated controls and health monitoring fiberoptic shaft monitor

    NASA Technical Reports Server (NTRS)

    Coleman, P.; Darejeh, H.; Collins, J. J.

    1989-01-01

    Recent work was performed on development optical technology to provide real time monitoring of shaft speed, shaft axial displacement, and shaft orbit of the OTVE hydrostatic bearing tester. Results show shaft axial displacement can be optically measured (at the same time as shaft orbital motion and speed) to within 0.3 mills by two fiber optic deflectometers. The final results of this condition monitoring development effort are presented.

  1. The Case for Distributed Engine Control in Turbo-Shaft Engine Systems

    NASA Technical Reports Server (NTRS)

    Culley, Dennis E.; Paluszewski, Paul J.; Storey, William; Smith, Bert J.

    2009-01-01

    The turbo-shaft engine is an important propulsion system used to power vehicles on land, sea, and in the air. As the power plant for many high performance helicopters, the characteristics of the engine and control are critical to proper vehicle operation as well as being the main determinant to overall vehicle performance. When applied to vertical flight, important distinctions exist in the turbo-shaft engine control system due to the high degree of dynamic coupling between the engine and airframe and the affect on vehicle handling characteristics. In this study, the impact of engine control system architecture is explored relative to engine performance, weight, reliability, safety, and overall cost. Comparison of the impact of architecture on these metrics is investigated as the control system is modified from a legacy centralized structure to a more distributed configuration. A composite strawman system which is typical of turbo-shaft engines in the 1000 to 2000 hp class is described and used for comparison. The overall benefits of these changes to control system architecture are assessed. The availability of supporting technologies to achieve this evolution is also discussed.

  2. TNX/HLW Long Shaft Pumps 1995-2000

    SciTech Connect

    VanPelt, B.

    2002-04-03

    Problems with long shaft pumps are becoming clearer due to increased use, better instrumentation, more analysis, and increased testing activity. The problems are with reliability and not with hydraulic performance. The root cause of reliability problems is usually excessive vibration caused by design. The outlook for satisfactory pumps is improved as understanding of problems increases. Promising developments are emerging such as the tilt pad bearing. Alternative configurations, such as gas filled columns and submerged motor pumps, will require development. Continued development, in general, should be expected due to changing technology and industry changes. This report describes thirteen distinct pump programs starting with leakage of original mixer pumps in the 1980s and ending with the testing of tilt pad bearings now in progress. Eight of the programs occurred from 1996 to 2000. All involve long shaft pumps; all involve testing at TNX; and all involve a problem of some kind. The common technical issue among the activities is vibration and shaft (or rotor) instability due to journal bearings. In every case, excessive shaft vibration is a reasonable and probable explanation for some or all of the problems.

  3. Acromioclavicular Joint Dislocation with Ipsilateral Mid Third Clavicle, Mid Shaft Humerus and Coracoid Process Fracture - A Case Report.

    PubMed

    Sharma, Naveen; Mandloi, Avinash; Agrawal, Ashish; Singh, Shailendra

    2016-01-01

    The clavicle, humerus and acromioclavicular (AC) joint separately are very commonly involved in traumatic injuries around the shoulder. Acromioclavicular joint dislocation with distal clavicle fracture is a well recognized entity in clinical practice. AC joint dislocation with mid shaft clavicle fracture is uncommon and only few cases have been reported in literature. However, to the best of our knowledge, this is the first case report to describe an acromioclavicular dislocation with ipsilateral mid shaft clavicle, mid shaft humerus and coracoid process fracture. Fractures of the humerus and clavicle along with the acromioclavicular joint dislocation were fixed at the same setting. A 65-year-old male met with a high velocity road traffic accident. Plain radiographs showed displaced mid third clavicle fracture with acromioclavicular joint dislocation with mid shaft humerus fracture. Surgical fixation was planned for humerus with interlocking nail, clavicle with locking plate and acromioclavicular joint with reconstruction of coracoclavicular ligaments. Intraoperatively, coracoid process was found to have a comminuted fracture. The operative plan had to be changed on table as coracoclavicular fixation was not possible. So acromioclavicular joint fixation was done using tension band wiring and the coracoclavicular ligament was repaired using a 2-0 ethibond. The comminuted coracoid fracture was managed conservatively. K wires were removed at 6 weeks. Early mobilization was started. In acromioclavicular joint injuries, clavicle must be evaluated for any injury. Although it is more commonly associated with distal clavicle fractures, it can be associated with middle third clavicle fractures. As plain radiographs, AP view are most of the times insufficient for viewing integrity of coracoid process, either special views like Stryker notch or CT scan may help in diagnosing such concealed injuries. When associated with fractures of the humerus and clavicle, anatomical

  4. EPIDEMIOLOGICAL AND RADIOLOGICAL EVALUATION OF FEMORAL SHAFT FRACTURES: STUDY OF 200 CASES

    PubMed Central

    de Moraes, Frederico Barra; da Silva, Luciano Lucindo; Ferreira, Fábio Vieira; Ferro, Ademar Martins; da Rocha, Valney Luís; Teixeira, Kim-Ir-Sen Santos

    2015-01-01

    Objective: to evaluate epidemiological and radiological characteristics of the femoral shaft fractures, surgically treated from 1990 to 2005 at Hospital de Acidentados – Clínica Santa Isabel – in Goiânia, Goiás, aiming to contribute to better preventive and therapeutic measures planning to adopt on those fractures. Methods: 200 patients' files and x-rays with femoral shaft fractures have been retrospectively evaluated. Patients below the age of 10 years were not included because the treatment for this group was conservative. 25 files have been discarded for not supplying all the necessary data to the study. The patients were assessed for sex, age, side of the fracture, bone exposure, mechanisms of trauma, classification of the fractures, associated trauma, time for bone healing and types of surgical devices. Statistic analyses were made by chi-squared, Fisher and Student's-t tests, adopting as a significance level p<0.05. Results: significant results (p < 0.05) were found in: 70% of men, 80% closed fractures and 65% of women above the age of 60. Fractures resulting from simple falls were more frequent in women, above 60 years old, with simpler traces, and the ones caused by projectiles of firearm in men, from 20 to 60 years, with unstable traces. Trampling accidents were prevalent among youngsters between 10 and 19 years old. Car accidents showed all the types of fractures, mostly associated to other traumas, reaching its peak incidence in the age group of 20-30 years. The treatment with Küntscher Nail resulted in a longer mean consolidation time, as well as fractures with unstable traces (B3,C1,C2,C3). Conclusion: we found a bi-modal characteristic the femoral shaft fractures, consistently to literature data, where the high energy mechanisms (traffic accidents, high falls and wounds from firearms), have been more frequent in young adults, men, generating unstable traces of fractures, with more serious associated trauma, while the other group with low

  5. Design criteria monograph on turbopump shafts and couplings

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Monograph reviews and assesses current design practices, and considers all aspects of turbopump system shaft dynamics peculiar to and necessary to shaft and coupling design. Associated components (bearings, housing, etc.) that influence shaft or coupling design are treated to extent necessary to define that influence.

  6. Distinctive Damage Patterns on THA Metal Bearing Surfaces: Case Studies

    PubMed Central

    Heiner, Anneliese D; Tikekar, Nishant M; Kruger, Karen M; Lannutti, John J; Brown, Thomas D

    2014-01-01

    Retrieval analysis of total joint arthroplasty components has primarily focused on assessing wear or other damage to polyethylene components. As damage to the opposing bearing surface can accelerate polyethylene wear and damage, and especially with the use of hard-on-hard articulations, retrieval analysis benefits from incorporating evaluation of hard bearing surfaces as well. The purpose of this study is to report six case studies of metal bearing surfaces with distinctive damage patterns, to interpret them in the context of adverse events plausibly responsible for their creation, and to suggest their likely clinical or scientific significance. The specific damage patterns reported here are 1) extensive scraping, 2) circumferential discoloration, 3) a long chain of periodic micro-indentations, 4) pitting with deposits, 5) scratches with small-radius directional changes, and 6) indentation with scraping. PMID:25328465

  7. A New 1000 F Magnetic Bearing Test Rig

    NASA Technical Reports Server (NTRS)

    Kascak, Albert F.; Montague, Gerald T.; Brown, Gerald V.; Palazzolo, Alan B.

    1997-01-01

    NASA and the Army are currently exploring the possibility of using magnetic bearings in gas turbine engines. The use of magnetic bearings in gas turbine engines could increase the reliability by eliminating the lubrication system. The use of magnetic bearings could also increase the speed and the size of the shafts in the engine, thus reducing vibrations and possibly eliminating third bearings. Magnetic bearings can apply forces to the shafts and move them so that blade tips and seals do not rub. This could be part of an active vibration cancellation system. Also, whirling (displacing the shaft center line) may delay rotating stall and increase the stall margin of the engine. Magnetic bearings coupled with an integral starter generator could result in a more efficient 'more electric' engine. The IHPTET program, a joint DOD-industry program, has identified a need for a high temperature, (as high as 1200 F), magnetic bearing that could be demonstrated in a phase m engine. A magnetic bearing is similar to an electric motor. The magnetic bearing has a laminated rotor and stator made out of cobalt steel. The stator has a series of coils of wire wound around it. These coils f u. a series of electromagnets around the circumference. These magnets exert a force on the rotor to keep the rotor in the center of the cavity. The centering force is commanded by a controller based on shaft position, (measured by displacement probes). The magnetic bearing can only pull and is basically unstable before active control is applied The engine shafts, bearings, and case form a flexible structure which contain a large number of modes. A controller is necessary to stabilize these modes. A power amplifier is also necessary to provide the current prescribed by the controller to the magnetic bearings. In case of very high loads, a conventional back up bearing will engage and stop the rotor and stator from rubbing.

  8. A New 1000 F Magnetic Bearing Test Rig

    NASA Technical Reports Server (NTRS)

    Kascak, Albert F.; Montague, Gerald T.; Brown, Gerald V.; Palazzolo, Alan B.

    1997-01-01

    NASA and the Army are currently exploring the possibility of using magnetic bearings in gas turbine engines. The use of magnetic bearings in gas turbine engines could increase the reliability by eliminating the lubrication system. The use of magnetic bearings could also increase the speed and the size of the shafts in the engine, thus reducing vibrations and possibly eliminating third bearings. Magnetic bearings can apply forces to the shafts and move them so that blade tips and seals do not rub. This could be part of an active vibration cancellation system. Also, whirling (displacing the shaft center line) may delay rotating stall and increase the stall margin of the engine. Magnetic bearings coupled with an integral starter generator could result in a more efficient 'more electric' engine. The IHPTET program, a joint DOD-industry program, has identified a need for a high temperature, (as high as 1200 F), magnetic bearing that could be demonstrated in a phase m engine. A magnetic bearing is similar to an electric motor. The magnetic bearing has a laminated rotor and stator made out of cobalt steel. The stator has a series of coils of wire wound around it. These coils f u. a series of electromagnets around the circumference. These magnets exert a force on the rotor to keep the rotor in the center of the cavity. The centering force is commanded by a controller based on shaft position, (measured by displacement probes). The magnetic bearing can only pull and is basically unstable before active control is applied The engine shafts, bearings, and case form a flexible structure which contain a large number of modes. A controller is necessary to stabilize these modes. A power amplifier is also necessary to provide the current prescribed by the controller to the magnetic bearings. In case of very high loads, a conventional back up bearing will engage and stop the rotor and stator from rubbing.

  9. Resilient shaft mounting for pump

    SciTech Connect

    Valentine, W.

    1990-06-12

    This patent describes a pump. It comprises: a tube having a centrifugal pump mounted on an upper end thereof, the centrifugal pump having an inlet coaxial with the tube, an outlet disposed radially and an impeller rotatable in a housing to pump a liquid; at least one propeller disposed in the tube below the centrifugal pump, the propeller being rotatable to draw fluid upwardly in the tube; a shaft connecting the impeller of the centrifugal with the propeller in the tube; at least one triangular support for the shaft, having three resilient planar plates dimensioned to be bowed inwardly in the tube and enclosing the shaft. The plates are discrete sections, each having ends disposed against an inner surface of the tube and against an adjoining one of the plates, an intermediate portion of each of the plates resiliently bearing inwardly toward the shaft; and, a resilient bushing disposed between the plates and the shaft, the resilient bushing being a round tube deformed into a triangular shape by pressure of the plates; whereby the shaft is supported coaxially in the tube.

  10. Flexible intramedullary nailing for treatment of proximal humeral and humeral shaft fractures in children: A retrospective series of 118 cases.

    PubMed

    Pogorelić, Z; Kadić, S; Milunović, K P; Pintarić, I; Jukić, M; Furlan, D

    2017-09-01

    The aim of this study was to analyze outcomes of treatment and complications in children treated with flexible intramedullary nailing (FIN) due to humeral fracture. The FIN for treatment of humeral fractures in children would allow an early functional and cast-free follow-up with a quick pain reduction and low complication rate. From May 2002 until May 2016 case records of all children who underwent fixation with titanium intramedullary nails because of humeral fracture were retrospectively reviewed. The study included 118 patients treated with FIN for proximal humeral or humeral shaft fracture. The average age at the time of trauma was 12 years. Mean follow-up was 77 months. Left hand was affected in 51% of patients. The most common mechanism of injury was fall (n=58), followed by sports injuries, road traffic accidents, pathological fractures, motorbike accidents and bicycle riding. There were no residual valgus/varum deformities. All patients achieved complete radiographic healing at a mean of 7.5 weeks. Nine complications were recorded: 1 humeral shaft fracture in patient with osteogenesis imperfecta, 4 entry site skin irritations, 2 skin infections and 2 radial nerve injuries. There were no cases of delayed union, nonunion or mal-union. After removal of the nails, all patients regained full function and all complications resolved. The FIN for humeral fractures is a minimally invasive, simple and well reproducible technique with very low complication rate. The FIN for treatment of humeral fractures shows very good functional and cosmetic results. It allows an early functional and cast-free follow-up with a quick pain reduction. Level IV - retrospective study. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  11. System for testing bearings

    NASA Technical Reports Server (NTRS)

    Gibson, John C. (Inventor)

    1993-01-01

    Disclosed here is a system for testing bearings wherein a pair of spaced bearings provides support for a shaft on which is mounted a bearing to be tested, this bearing being mounted in a bearing holder spaced from and in alignment with the pair of bearings. The bearing holder is provided with an annular collar positioned in an opening in the bearing holder for holding the bearing to be tested. A screw threaded through the bearing holder into engagement with the annular collar can be turned to force the collar radially out of alignment with the pair of bearings to apply a radial load to the bearing.

  12. Stress fractures of the femoral shaft in women's college lacrosse: a report of seven cases and a review of the literature.

    PubMed

    Kang, L; Belcher, D; Hulstyn, M J

    2005-12-01

    Stress fractures do not often occur in the shaft of the femur. They are more common in the femoral neck, the tibial shaft, the metatarsals, and other bones of the foot. In female athletes, stress fractures classically afflict the distance runner, the ballerina, the gymnast, and the figure skater. To describe the clinical presentation, diagnosis, treatment, and outcome of seven college female lacrosse players with femoral shaft stress fractures, and review the literature. The unusual results of this study support the principle that clinical suspicion should be high when treating any female athlete regardless of the sport. In this case series, an abrupt change in the quality of the running surface during the competitive training season was the only underlying common thread among the athletes. The findings suggest that risk factors for the female athlete are variable and are no longer limited to the undernourished or overtrained.

  13. Stress fractures of the femoral shaft in women's college lacrosse: a report of seven cases and a review of the literature

    PubMed Central

    Kang, L; Belcher, D; Hulstyn, M

    2005-01-01

    Background: Stress fractures do not often occur in the shaft of the femur. They are more common in the femoral neck, the tibial shaft, the metatarsals, and other bones of the foot. In female athletes, stress fractures classically afflict the distance runner, the ballerina, the gymnast, and the figure skater. Objectives: To describe the clinical presentation, diagnosis, treatment, and outcome of seven college female lacrosse players with femoral shaft stress fractures, and review the literature. Results: The unusual results of this study support the principle that clinical suspicion should be high when treating any female athlete regardless of the sport. In this case series, an abrupt change in the quality of the running surface during the competitive training season was the only underlying common thread among the athletes. Conclusion: The findings suggest that risk factors for the female athlete are variable and are no longer limited to the undernourished or overtrained. PMID:16306496

  14. Introduction to ball bearings

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1981-01-01

    The purpose of a ball bearing is to provide a relative positioning and rotational freedom while transmitting a load between two structures, usually a shaft and a housing. For high rotational speeds (e.g., in gyroscope ball bearings) the purpose can be expanded to include rotational freedom with practically no wear in the bearing. This condition can be achieved by separating the bearing parts with a coherent film of fluid known as an elastohydrodynamic film. This film can be maintained not only when the bearing carries the load on a shaft, but also when the bearing is preloaded to position the shaft to within micro- or nano-inch accuracy and stability. Background information on ball bearings is provided, different types of ball bearings and their geometry and kinematics are defined, bearing materials, manufacturing processes, and separators are discussed. It is assumed, for the purposes of analysis, that the bearing carries no load.

  15. High speed hybrid bearing comprising a fluid bearing and a rolling bearing convected in series

    NASA Technical Reports Server (NTRS)

    Anderson, W. J. (Inventor)

    1973-01-01

    A description is given of an antifriction bearing and a process by which its fatigue life may be extended. The method involves a rotating shaft supported by a fluid bearing and a rolling element bearing coupled in series. Each bearing turns at a fraction of the rotational speed of the shaft. The fluid bearing is preferably conical, thereby providing thrust and radial load support in a single bearing structure.

  16. Synthetic Fiber "Teddy Bear" Conjunctival Granuloma; a Case Report.

    PubMed

    Aliakbar-Navahi, Roshanak; Roozitalab, Mohammad Hossein; Ashraf, Mohammad Javad; Hakimzadeh, Afsoon

    2015-01-01

    To report the clinicopathologic features of a case of conjunctival synthetic fiber granuloma. A 6-year-old girl presented with a slow-growing red nodule in the right inferior conjunctival sac with no history of surgery or trauma. Histopathological examination revealed foreign body type granulomatous inflammation around birefringent fibers of variable colors consistent with synthetic fiber granuloma. This is the first case report of synthetic fiber (teddy bear) conjunctival granuloma from Iran. Despite its scarcity, ophthalmologists should consider this type of granuloma in the differential diagnoses of childhood conjunctival lesions especially when the lesion is unilateral and inferior.

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

    NASA Technical Reports Server (NTRS)

    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.

  18. Shaft Adapter For Data Coupler

    NASA Technical Reports Server (NTRS)

    Elliott, James R.; Lord, Mark T.

    1990-01-01

    Shaft adapter developed to provide means for securing Acurex 1200B universal data coupler to rotating instrumented shaft. Consists of two major parts: shaft sleeve and shaft clamp. Provides for accurate measurements of stresses and strains in shaft.

  19. Endurance and failure characteristics of main-shaft jet engine bearings at 3x10 to the 6th power DN

    NASA Technical Reports Server (NTRS)

    Bamberger, E. N.; Zaretsky, E. V.; Signer, H.

    1976-01-01

    Groups of thirty 120-mm bore angular contact ball bearings were endurance tested at a speed of 12,000 and 25,000 rpm and a thrust load of 66 721 N. The bearings were manufactured from a single heat of VIM-VAR AISI M-50 steel. At 1.44X1 million and 3.0x1 million DN, 84 483 and 74 800 bearing test hours were accumulated, respectively. Test results were compared with similar bearings made from CVM AISI M-50 steel run under the same conditions. Bearing lives at speeds of 3x1 million DN with the VIM-VAR AISI M-50 steel were nearly equivalent to those obtained at lower speeds. A combined processing and material life factor of 44 was found for VIM-VAR AISI M-50 steel. Continuous running after a spall has occurred at 3.0x1 million DN can result in a destructive fracture of the bearing inner race.

  20. Shaft speed control

    NASA Technical Reports Server (NTRS)

    Ford, A. G.

    1979-01-01

    Simple mechanism controls rotation of heavy-duty shaft by mechanical comparison with rotation of small, precise, stepper motor. Mechanism can be used to limit winding and unwinding speeds of large spools and reels and to control speed of other rotating shafts. Setup incorporates reference shaft geared down from stepper motor and feedback shaft geared up from shaft to be controlled. Feedback and reference shafts are coupled with brake assembly inside stationary cylinder. When work shaft speeds up, brakes are activated automatically to slow it down.

  1. Vibration Transmission through Bearings with Application to Gearboxes

    NASA Technical Reports Server (NTRS)

    Fleming, David P.

    2007-01-01

    Cabin noise has become a major concern to manufacturers and users of helicopters. Gear noise is the largest part of this unwanted sound. The crucial noise path is generally considered to be from the gears through the gear-supporting shafts and bearings into the gearbox case, and from there either through the gearbox mounts or the surrounding air to the helicopter cabin. If the noise, that is, the gear and shaft vibration, can be prevented from traveling through the gearbox bearings, then the noise cannot make its way into the helicopter cabin. Thus the vibration-transmitting properties of bearings are of paramount importance. This paper surveys the literature concerning evaluation of properties for the types of bearings used in helicopter gearboxes. A simple model is proposed to evaluate vibration transmission, using measured or calculated bearing stiffness and damping. Less-commonly used types of gearbox bearings (e.g., fluid film) are evaluated for their potential in reducing vibration transmission.

  2. Blind shaft development

    SciTech Connect

    Fiscor, S.

    2009-02-15

    The article discusses how Shaft Drillers International (SDI) is breaking new ground in shaft development and ground stabilization. Techniques of blind shaft drilling and raise bore shaft development developed by SDI are briefly explained. An associated company, Coastal Drilling East, deals with all types of ground improvement such as pre-grouting work for shafts, grouting of poor soil and water leaks into the mine. 3 photos.

  3. Rotor and bearing system for a turbomachine

    DOEpatents

    Lubell, Daniel; Weissert, Dennis

    2006-09-26

    A rotor and bearing system for a turbomachine. The turbomachine includes a drive shaft, an impeller positioned on the drive shaft, and a turbine positioned on the drive shaft proximate to the impeller. The bearing system comprises one gas journal bearing supporting the drive shaft between the impeller and the turbine. The area between the impeller and the turbine is an area of increased heat along the drive shaft in comparison to other locations along the drive shaft. The section of the drive shaft positioned between impeller and the turbine is also a section of the drive shaft that experiences increased stressed and load in the turbomachine. The inventive bearing machine system positions only one radial bearing in this area of increased stress and load.

  4. A Case of Beare-Stevenson Syndrome with Unusual Manifestations

    PubMed Central

    Ron, Nitin; Leung, Samuel; Carney, Erin; Gerber, Alexis; David, Karen Laurie

    2016-01-01

    Case series Patient: — Final Diagnosis: Beare-Stevenson syndrome Symptoms: — Medication: — Clinical Procedure: Genetic analysis Specialty: Pediatrics and Neonatology Objective: Rare disease Background: Beare-Stevenson syndrome (BSS) is an extremely rare genetic disorder, with fewer than 25 cases reported worldwide. This autosomal dominant syndrome has been linked to two mutations in the fibroblast growth factor receptor 2 gene (FGFR2), Tyr375Cys and Ser372Cys, both causing amino acid changes. Case Report: BSS is characterized by a range of morphological features, some more classically associated than others, of which craniosynostosis has been almost uniformly present. Other common features include cutis gyrata, acanthosis nigricans, ear and eye defects, skin/mucosal tissue tags, prominent umbilical stump, and anogenital anomalies. This account reports what we believe to be the 25th case of BSS, and exhibits a constellation of the characteristic features similar to those previously described, including the presence of cutis gyrata, proptosis, a bifid scrotum, and hypospadias. However, craniosynostosis was not detected prenatally by ultrasound or at birth. Prenatal ultrasound may detect some dysmorphic features of BSS. Many of these features have also been associated with other genetic disorders with overlapping phenotypes. Our case presented with the unusual features of a natal tooth and absence of craniosynostosis at birth. At birth, a diagnosis of BSS was suspected based on clinical features despite the absence of craniosynostosis. This was later confirmed with the use of molecular analysis, revealing a Tyr375Cys mutation of exon 9 of the FGFR2 gene. Conclusions: We suggest that a normal antenatal ultrasound scan and the absence of craniosynostosis at birth should not preclude further workup for BSS if this possibility is clinically suspected. PMID:27079505

  5. A hydrodynamically suspended, magnetically sealed mechanically noncontact axial flow blood pump: design of a hydrodynamic bearing.

    PubMed

    Mitamura, Yoshinori; Kido, Kazuyuki; Yano, Tetsuya; Sakota, Daisuke; Yambe, Tomoyuki; Sekine, Kazumitsu; OKamoto, Eiji

    2007-03-01

    To overcome the drive shaft seal and bearing problem in rotary blood pumps, a hydrodynamic bearing, a magnetic fluid seal, and a brushless direct current (DC) motor were employed in an axial flow pump. This enabled contact-free rotation of the impeller without material wear. The axial flow pump consisted of a brushless DC motor, an impeller, and a guide vane. The motor rotor was directly connected to the impeller by a motor shaft. A hydrodynamic bearing was installed on the motor shaft. The motor and the hydrodynamic bearing were housed in a cylindrical casing and were waterproofed by a magnetic fluid seal, a mechanically noncontact seal. Impeller shaft displacement was measured using a laser sensor. Axial and radial displacements of the shaft were only a few micrometers for motor speed up to 8500 rpm. The shaft did not make contact with the bearing housing. A flow of 5 L/min was obtained at 8000 rpm at a pressure difference of 100 mm Hg. In conclusion, the axial flow blood pump consisting of a hydrodynamic bearing, a magnetic fluid seal, and a brushless DC motor provided contact-free rotation of the impeller without material wear.

  6. Adamantinoma of tibial shaft.

    PubMed

    A, Joshi; Kc, B R; Basnet, S B; Panth, R; Shrestha, R L; Chand, P; Thapa, B B

    2009-01-01

    Adamantinoma is an extremely rare primary bony neoplasm. Because of its malignant nature, accurate and early diagnosis is very important. On the other hand adamantinoma mimics many benign conditions, so it is doubly important to establish correct tissue diagnosis to avoid radical surgery with morbidities. Because of its rarity, diagnosing adamantinoma still remains difficult, even if when it occurs in classical sites. We report a case of adamantinoma of tibial shaft diaphysis in a 23 year male. In this case, because of classic clinic-radiological features, we were suspecting adamantinoma from very beginning but final diagnosis was delayed for nine months.

  7. Methods and systems for micro bearings

    DOEpatents

    Stalford, Harold L

    2015-01-27

    A micro drive assembly may comprise a substrate, a micro shaft oriented in-plane with the substrate and at least one micro bearing to support rotation of the micro shaft. The micro shaft and micro bearing may be in or less than the micrometer domain.

  8. The Welfare of Bears in Zoos: A Case Study of Poland.

    PubMed

    Maślak, Robert; Sergiel, Agnieszka; Bowles, David; Paśko, Łukasz

    2016-01-01

    The welfare of captive bears became a big issue of concern in Poland when a case of a bear being ill-treated became a high-profile case in the media. This case created a challenge to verify, study, and understand the main problems associated with bear keeping so that zoos could significantly improve the conditions in which they keep bears or ensure they keep bears at the minimum required standards. The results presented here are from 1 of the few countrywide studies of captive bear conditions conducted in all the captive institutions in Poland that keep bears. Thirteen institutions kept bears at the time of the study (2007-2009), including 54 individuals of 5 species. Major welfare problems were identified, and the results have been used to challenge zoos to address the changes required and focus the government's attention on areas that require legislative improvement.

  9. Simulating seepage into mine shafts and tunnels with MODFLOW.

    PubMed

    Zaidel, Jacob; Markham, Bradley; Bleiker, David

    2010-01-01

    In cases when an equivalent porous medium assumption is suitable for simulating groundwater flow in bedrock aquifers, estimation of seepage into underground mine workings (UMWs) can be achieved by specifying MODFLOW drain nodes at the contact between water bearing rock and dewatered mine openings. However, this approach results in significant numerical problems when applied to simulate seepage into an extensive network of UMWs, which often exist at the mine sites. Numerical simulations conducted for individual UMWs, such as a vertical shaft or a horizontal drift, showed that accurate prediction of seepage rates can be achieved by either applying grid spacing that is much finer than the diameter/width of the simulated openings (explicit modeling) or using coarser grid with cell sizes exceeding the characteristic width of shafts or drifts by a factor of 3. Theoretical insight into this phenomenon is presented, based on the so-called well-index theory. It is demonstrated that applying this theory allows to minimize numerical errors associated with MODFLOW simulation of seepage into UMWs on a relatively coarse Cartesian grid. Presented examples include simulated steady-state groundwater flow from homogeneous, heterogeneous, and/or anisotropic rock into a vertical shaft, a horizontal drift/cross-cut, a ramp, two parallel drifts, and a combined system of a vertical shaft connected to a horizontal drift.

  10. [Post-traumatic pseudoaneurysm of the anterior tibial artery secondary to tibial shaft fracture. Case report].

    PubMed

    Gómez-Salazar, J; Tovar-López, J; Hernández-Rodríguez, G; De la Concha-Ureta, H

    2016-01-01

    Arterial pseudoaneurysm of the lower limb is an infrequent entity, particularly in the infrapopliteal segment. It is commonly associated to vascular repairs or follows a localized arterial lesion, a fracture or a surgical procedure. There is little information in Mexico about this entity in cases involving the anterior tibial artery, and secondary to trauma and osteosynthesis. Given that sudden bleeding due to rupture of the pseudoaneurysm is a possible catastrophic outcome for the viability of the segment, it is important to timely detect and diagnose the pseudoaneurysm. Treatment indications contained in the international literature are controversial. Solution-oriented approaches may be either surgical or endovascular. Current reports show that the best treatment option is an autologous saphenous vein graft, which maintains blood flow and minimizes the risk of peripheral ischemia. The purpose of this paper is to report the case of a patient who sustained the above mentioned complication and provide a literature review. This topic should be further investigated, as this condition may go unnoticed in a large number of cases, given that its symptoms are silent.

  11. Cryogenic Hybrid Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    Meeks, Crawford R.; Dirusso, Eliseo; Brown, Gerald V.

    1994-01-01

    Cryogenic hybrid magnetic bearing is example of class of magnetic bearings in which permanent magnets and electromagnets used to suspend shafts. Electromagnets provide active control of position of shaft. Bearing operates at temperatures from -320 degrees F (-196 degrees C) to 650 degrees F (343 degrees C); designed for possible use in rocket-engine turbopumps, where effects of cryogenic environment and fluid severely limit lubrication of conventional ball bearings. This and similar bearings also suitable for terrestrial rotating machinery; for example, gas-turbine engines, high-vacuum pumps, canned pumps, precise gimbals that suspend sensors, and pumps that handle corrosive or gritty fluids.

  12. Cryogenic Hybrid Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    Meeks, Crawford R.; Dirusso, Eliseo; Brown, Gerald V.

    1994-01-01

    Cryogenic hybrid magnetic bearing is example of class of magnetic bearings in which permanent magnets and electromagnets used to suspend shafts. Electromagnets provide active control of position of shaft. Bearing operates at temperatures from -320 degrees F (-196 degrees C) to 650 degrees F (343 degrees C); designed for possible use in rocket-engine turbopumps, where effects of cryogenic environment and fluid severely limit lubrication of conventional ball bearings. This and similar bearings also suitable for terrestrial rotating machinery; for example, gas-turbine engines, high-vacuum pumps, canned pumps, precise gimbals that suspend sensors, and pumps that handle corrosive or gritty fluids.

  13. Vibration control of rotor shaft

    NASA Technical Reports Server (NTRS)

    Nonami, K.

    1985-01-01

    Suppression of flexural forced vibration or the self-excited vibration of a rotating shaft system not by passive elements but by active elements is described. The distinctive feature of this method is not to dissipate the vibration energy but to provide the force cancelling the vibration displacement and the vibration velocity through the bearing housing in rotation. Therefore the bearings of this kind are appropriately named Active Control Bearings. A simple rotor system having one disk at the center of the span on flexible supports is investigated in this paper. The actuators of the electrodynamic transducer are inserted in the sections of the bearing housing. First, applying the optimal regulator of optimal control theory, the flexural vibration control of the rotating shaft and the vibration control of support systems are performed by the optimal state feedback system using these actuators. Next, the quasi-modal control based on a modal analysis is applied to this rotor system. This quasi-modal control system is constructed by means of optimal velocity feedback loops. The differences between optimal control and quasi-modal control are discussed and their merits and demerits are made clear. Finally, the experiments are described concerning only the optimal regulator method.

  14. Bent shaft motor

    DOEpatents

    Benavides, Gilbert L.

    1998-01-01

    A nonelectromagnetic motor comprising a base, a bent shaft which is rotable relative to the base wherein the bent shaft comprises a straight portion aligned with a main axis and an offset portion that is offset with respect to the main axis; and a drive means for driving the offset portion of the bent shaft along a generally circular path in a plane perpendicular to the main axis to rotate the bent shaft. The bent shaft and drive means for driving the bent shaft can be selected from piezoelectric, magnetostrictive, rheological and shape memory alloys. The drive means of the nonelectromagnetic motor can additionally comprise a shell which shell surrounds and houses the bent shaft and precesses or gyrates which in turn causes the bent drive shaft to rotate. The nonelectromagnetic motor does not rely on friction for the application of torque upon a rotor.

  15. Bent shaft motor

    DOEpatents

    Benavides, G.L.

    1998-05-05

    A nonelectromagnetic motor comprising a base, a bent shaft which is rotatable relative to the base wherein the bent shaft comprises a straight portion aligned with a main axis and an offset portion that is offset with respect to the main axis; and a drive means for driving the offset portion of the bent shaft along a generally circular path in a plane perpendicular to the main axis to rotate the bent shaft. The bent shaft and drive means for driving the bent shaft can be selected from piezoelectric, magnetostrictive, rheological and shape memory alloys. The drive means of the nonelectromagnetic motor can additionally comprise a shell which shell surrounds and houses the bent shaft and precesses or gyrates which in turn causes the bent drive shaft to rotate. The nonelectromagnetic motor does not rely on friction for the application of torque upon a rotor. 11 figs.

  16. Hybrid Hydrostatic/Transient Roller Bearing Assembly

    NASA Technical Reports Server (NTRS)

    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.

  17. Gearbox Reliability Collaborative High-Speed Shaft Calibration

    SciTech Connect

    Keller, J.; McNiff, B.

    2014-09-01

    Instrumentation has been added to the high-speed shaft, pinion, and tapered roller bearing pair of the Gearbox Reliability Collaborative gearbox to measure loads and temperatures. The new shaft bending moment and torque instrumentation was calibrated and the purpose of this document is to describe this calibration process and results, such that the raw shaft bending and torque signals can be converted to the proper engineering units and coordinate system reference for comparison to design loads and simulation model predictions.

  18. Compliant hydrodynamic fluid journal bearing

    NASA Technical Reports Server (NTRS)

    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.

  19. Assessment of the operating characteristics of the SSME LOX turbopump pump-end bearing

    NASA Technical Reports Server (NTRS)

    New, L. S.; Tiller, B. K.

    1984-01-01

    A bearing/shaft model of the SSME LOX turbopump was developed using the SHABERTH bearing/shaft math modeling computer code. A previously developed bearing/shaft thermal model of the SSME LOX turbopump turbine and bearing was used in conjunction with SHABERTH to evaluate the thermomechanical operating characteristics of the LOX turbopump end bearings. Results show that for the two unmounted diametrical clearances evaluated (4.0 mils and 6.3 mils), the inboard pump end bearing supports about 81% of the isolator load for the small clearance and 77% of the isolator load for the larger clearance. Bearing clearance changes due to thermal effects were 40% for the 4.0 mil diametrical clearance case and 19% for the 6.3 mil clearance case evaluated. The thermal analysis included evaluation of bearing temperatures for a subcooled case and a saturated case. Results indicate that no drastic temperature change occurred between the two cases. Since the rolling element and race surfaces of the subcooled case were at temperatures sufficiently high enough to be vapor blanketed, exceeding saturation temperature at the bearing inlet did not increase surface temperatures greatly.

  20. The Problem of Carbon Dioxide Emissions from Closed Coal Mine Shafts - The Overview and the Case Study

    NASA Astrophysics Data System (ADS)

    Wrona, Paweł; Sułkowski, Józef; Różański, Zenon; Pach, Grzegorz

    2016-09-01

    Greenhouse gas emissions are a common problem noticed in every mining area just after mine closures. However, there could be a significant local gas hazard for people with continuous (but variable) emission of these gases into the atmosphere. In the Upper Silesia area, there are 24 shafts left for water pumping purposes and gases can flow through them hydraulically. One of them - Gliwice II shaft - was selected for inspection. Carbon dioxide emission with no methane was detected here. Changes in emission and concentration of carbon dioxide around the shaft was the aim of research carried out. It was stated that a selected shaft can create two kinds of gas problems. The first relates to CO2 emission into the atmosphere. Possible emission of that gas during one minute was estimated at 5,11 kg CO2/min. The second problem refers to the local hazard at the surface. The emission was detected within a radius of 8m from the emission point at the level 1m above the ground. These kinds of matters should be subject to regular gas monitoring and reporting procedures.

  1. Coupled shaft-torsion and blade-bending vibrations of a rotating shaft-disk-blade unit

    SciTech Connect

    Huang, S.C.; Ho, K.B.

    1996-01-01

    A new approach to analyzing the dynamic coupling between shaft torsion and blade bending of a rotating shaft-disk-blade unit is introduced. The approach allows the shaft to vibrate freely around its rotation axis instead of assuming a periodic perturbation of the shaft speed that may accommodate the shaft flexibility only to a limited extent. A weighted residual method is applied, and the receptances at the connections of blades and shaft-disk are formulated. Numerical examples are given for cases with between two and six symmetrically arranged blades. The results show not only coupling between the shaft, disk, and blades, but also coupling between individual blades where the shaft acts as a rigid support and experiences no torsional vibration. The blade-coupling modes occurred only in repeated frequencies. Finally, the effect of shaft speed on the modal frequencies was investigated. Plots illustrating the occurrence of critical speeds and flutter instabilities are presented.

  2. 8. Generator Barrel and Shaft of Unit 1, view to ...

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

    8. Generator Barrel and Shaft of Unit 1, view to the northwest, with turbine shaft and thrust bearing visible in upper center of photograph. - Washington Water Power Clark Fork River Noxon Rapids Hydroelectric Development, Powerhouse, South bank of Clark Fork River at Noxon Rapids, Noxon, Sanders County, MT

  3. The relationship of femoral neck shaft angle and adiposity to greater trochanteric pain syndrome in women. A case control morphology and anthropometric study

    PubMed Central

    Fearon, AM; Stephens, S; Cook, JL; Smith, PN; Neeman, T; Cormick, W; Scarvell, JM

    2012-01-01

    Objective To evaluate if pelvic or hip width predisposed women to developing greater trochanteric pain syndrome (GTPS). Design Prospective case control study. Participants Four groups were included in the study: those gluteal tendon reconstructions (n=31, GTR), those with conservatively managed GTPS (n=29), those with hip osteoarthritis (n=20, OA) and 22 asymptomatic participants (ASC). Methods Anterior-posterior pelvic x-rays were evaluated for femoral neck shaft angle; acetabular index, and width at the lateral acetabulum, and the superior and lateral aspects of the greater trochanter. Body mass index, and waist, hip and greater trochanter girth were measured. Data were analysed using a one-way analysis of variance (ANOVA; posthoc Scheffe analysis), then multivariate analysis. Results The GTR group had a lower femoral neck shaft angle than the other groups (p=0.007). The OR (95% CI) of having a neck shaft angle of less than 134°, relative to the ASC group: GTR=3.33 (1.26 to 8.85); GTPS=1.4 (0.52 to 3.75); OA=0.85 (0.28 to 2.61). The OR of GTR relative to GTPS was 2.4 (1.01 to 5.6). No group difference was found for acetabular or greater trochanter width. Greater trochanter girth produced the only anthropometric group difference (mean (95% CI) in cm) GTR=103.8 (100.3 to 107.3), GTPS=105.9 (100.2 to 111.6), OA=100.3 (97.7 to 103.9), ASC=99.1 (94.7 to 103.5), (ANOVA: p=0.036). Multivariate analysis confirmed adiposity is associated with GTPS. Conclusion A lower neck shaft angle is a risk factor for, and adiposity is associated with, GTPS in women. PMID:22547561

  4. SEAL FOR ROTATING SHAFT

    DOEpatents

    Coffman, R.T.

    1957-12-10

    A seal is described for a rotatable shaft that must highly effective when the shaft is not rotating but may be less effective while the shaft is rotating. Weights distributed about a sealing disk secured to the shaft press the sealing disk against a tubular section into which the shiilt extends, and whem the shaft rotates, the centrifugal forces on the weights relieve the pressurc of the sealing disk against the tubular section. This action has the very desirible result of minimizing the wear of the rotating disk due to contact with the tubular section, while affording maximum sealing action when it is needed.

  5. Turbine shaft fuel pump

    SciTech Connect

    Smith, R.

    1991-08-27

    This patent describes a turbine engine having a support housing, a shaft rotatably mounted in the support housing, an annular combustion chamber coaxial with the shaft and the support housing, the shaft having an axial passageway, injector nozzles aligned for discharging fuel into the combustion chamber, and means for pumping and metering a supply of fuel to the injector nozzles, the pumping and metering means. It comprises a flow passageway extending from a first end of the shaft axial passageway and to the injector nozzles the flow passageway comprising an annular chamber formed between two axially spaced and radially inwardly extending walls in the shaft, the annular chamber is open to the axial passageway while a periphery of the annular chamber is open to the injector nozzles, and pumping vanes disposed in the annular chamber, the vanes being secured to the shaft so that, upon rotation of the shaft, the vanes provided pressurized fuel from the passageway to the injectors.

  6. 13. Detail view of drum screen short shaft gears, journal ...

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

    13. Detail view of drum screen short shaft gears, journal bearing, rotation drive chain, upper sprocket gear, and drum screen edge in background, facing southeast (downstream) from drum screen cover. - Congdon Canal, Fish Screen, Naches River, Yakima, Yakima County, WA

  7. Bearing Tester Data Compilation Analysis, and Reporting and Bearing Math Modeling

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The magnitude and direction of fluid induced torques and forces on the 57 mm bearing cage is considered to be a contributing factor in possible cage instabilities that can produce intermittent high heating in the bearing. Analyses of the fluid forces and torques are presented. Heat generated by viscous fluid work was estimated for two flow diverter configurations and a coolant flow of 10 lbs/sec to support the thermal evaluation of the LOX Bearing Materials Tester. Results of the analysis of the LOX turbopump turbine end bearings are discussed. Coolant velocities for the no. 4 LOX turbopump turbine end bearings were estimated as a function of shaft speed and coolant flow rate. Contact angles and track width data were developed for the 57 mm bearing as functions of shaft speed, and axial and radial loads. The Advanced Dynamics of Rolling Elements (ADORE) computer program was installed on the MSFC UNIVAC 1100 and a test case successfully run. Both the text output and the plotting output were verified. The Bearing Seal and Materials Tester - Test Condition Data Base was developed. The parametric analysis of the operating characteristics of the LOX turbopump pump end bearing using the 45 mm bearing thermal model was begun.

  8. [Humeral shaft fractures].

    PubMed

    Schittko, A

    2004-08-01

    Since Lorenz Böhler postulated in his 1964 summary with the title "Against the operative treatment of fresh humeral shaft fractures" that the operative treatment is the exception in the therapy of humeral fractures times have changed. In the last years a conservative treatment of a humeral fracture is the exception and only used after straight indications. The operative therapy nowadays is the gold standard because of the development of new intramedullar and rotation stable implants in addition to the classical osteosynthesis with the plate. But even the external fixator for primary stabilisation in polytrauma patients or as rescue procedure after complications should be in repertory of every orthopedic surgeon. Attention should be put on the avoidance of primary and the correct treatment of secondary nerval lesions, esp. of the radial nerve. Here we are tending to the operative revision of the nerve in indistinct cases. In the treatment of the seldom humeral shaft fracture of the child conservative treatment is to prefer; in complications a resolute shift to a final operative stabilisation of the fracture is necessary.

  9. Shaft/shaft-seal interface characteristics of a multiple disk centrifugal blood pump.

    PubMed

    Manning, K B; Miller, G E

    1999-06-01

    A multiple disk centrifugal pump (MDCP) is under investigation as a potential left ventricular assist device. As is the case with most shaft driven pumps, leakage problems around the shaft/shaft seal interface are of major interest. If leakage were to occur during or after implantation, potential events such as blood loss, clotting, blood damage, and/or infections might result in adverse effects for the patient. Because these effects could be quite disastrous, potential shaft and shaft seal materials have been investigated to determine the most appropriate course to limit these effects. Teflon and nylon shaft seals were analyzed as potential candidates along with a stainless steel shaft and a Melonite coated shaft. The materials and shafts were evaluated under various time durations (15, 30, 45, and 60 min), motor speeds (800, 1,000, 1,200, and 1,400 rpm), and outer diameters (1/2 and 3/4 inches). The motor speed and geometrical configurations were typical for the MDCP under normal physiologic conditions. An air and water study was conducted to analyze the inner diameter wear, the inner temperature values, and the outer temperature values. Statistical comparisons were computed for the shaft seal materials, the shafts, and the outer diameters along with the inner and outer temperatures. The conclusions made from the results indicate that both the tested shaft seal materials and shaft materials are not ideal candidates to be used for the MDCP. Teflon experienced a significant amount of wear in air and water studies. Nylon did experience little wear, but heat generation was an evident problem. A water study on nylon was not conducted because of its molecular structure.

  10. 118. #3 SHAFT ALLEY (PROPELLER SHAFT) FORWARD LOOKING AFT ...

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

    118. #3 SHAFT ALLEY (PROPELLER SHAFT) - FORWARD LOOKING AFT ON PORT SIDE SHOWING THE SHAFT, SHAFT PACKING GLAND, SHAFT SEAL COOLING WATER LINE AND FIVE INCH FIRE MAIN PIPING. - U.S.S. HORNET, Puget Sound Naval Shipyard, Sinclair Inlet, Bremerton, Kitsap County, WA

  11. Mounting arrangement for the drive system of an air-bearing spindle on a machine tool

    DOEpatents

    Lunsford, J.S.; Crisp, D.W.; Petrowski, P.L.

    1987-12-07

    The present invention is directed to a mounting arrangement for the drive system of an air-bearing spindle utilized on a machine tool such as a lathe. The mounting arrangement of the present invention comprises a housing which is secured to the casing of the air bearing in such a manner that the housing position can be selectively adjusted to provide alignment of the air-bearing drive shaft supported by the housing and the air-bearing spindle. Once this alignment is achieved the air between spindle and the drive arrangement is maintained in permanent alignment so as to overcome misalignment problems encountered in the operation of the machine tool between the air-bearing spindle and the shaft utilized for driving the air-bearing spindle.

  12. Designing Shafts For Long Life

    NASA Technical Reports Server (NTRS)

    Loewenthal, Stuart H.

    1988-01-01

    Improved method developed for choosing sizes of power-transmitting shafts for limited or unlimited service lives under variety of operating conditions. Stress versus fatigue life of proposed shaft design plotted, modified to account for expected operating conditions and used to calculate shaft diameter required for given fatigue life. If diameter of shaft represented by plot equals or exceeds required diameter, shaft considered adequate.

  13. Method of measurement and analysis of the extent of wear of rope wheel bearings in Bogdanka coal mine

    SciTech Connect

    Mazurkiewicz, D.; Galinski, M.

    2007-03-15

    This paper presents the method of assessing rope wheel bearing wear, developed for the special case of a shaft hoist in the Bogdanka coal mine. The diagnosis method presented here may also be used for inspecting the bearings of direction rope wheels with movable axles and bearings placed outside the axle in bodies, of the type that prevail in Polish coal mining. The superiority of this method in comparison to those used so far consists in limiting the testing time, as well as in the fact that no extra workers are needed. Nor does it require special availability of the shaft equipment for performing the test.

  14. Shaft-Motion-Analyzing System

    NASA Technical Reports Server (NTRS)

    Randall, Richard L.; Collins, John J.; Coleman, Paul T.; Roschak, Edmund J.

    1993-01-01

    Optoelectronic system to monitor motions of turbopump shaft developed. Optical sensors detect passage of reflective triangles on shaft. Optical measurements processed in real time into indications of speed of rotation and of axial and lateral displacements of shaft.

  15. Shaft-Motion-Analyzing System

    NASA Technical Reports Server (NTRS)

    Randall, Richard L.; Collins, John J.; Coleman, Paul T.; Roschak, Edmund J.

    1993-01-01

    Optoelectronic system to monitor motions of turbopump shaft developed. Optical sensors detect passage of reflective triangles on shaft. Optical measurements processed in real time into indications of speed of rotation and of axial and lateral displacements of shaft.

  16. Vertical shaft windmill

    NASA Technical Reports Server (NTRS)

    Grana, D. C.; Inge, S. V., Jr. (Inventor)

    1983-01-01

    A vertical shaft has several equally spaced blades mounted. Each blade consists of an inboard section and an outboard section skew hinged to the inboard section. The inboard sections automatically adjust their positions with respect to the fixed inboard sections with changes in velocity of the wind. This windmill design automatically governs the maximum rotational speed of shaft.

  17. Gearbox Reliability Collaborative Investigation of Gearbox Motion and High-Speed-Shaft Loads

    SciTech Connect

    Keller, Jon; Guo, Yi; Sethuraman, Latha

    2016-03-18

    This paper extends a model-to-test validation effort to examine the effect of different constant rotor torque and moment conditions and intentional generator misalignment on the gearbox motion and high-speed-shaft loads. Fully validating gearbox motion and high-speed-shaft loads across a range of test conditions is a critical precursor to examining the bearing loads, as the gearbox motion and high-speed-shaft loads are the drivers of these bearing loads.

  18. Vibration transmission through rolling element bearings in geared rotor system, part 1. Ph.D. Thesis Final Report

    NASA Technical Reports Server (NTRS)

    Singh, Rajendra; Lim, Teik Chin

    1989-01-01

    A mathematical model is proposed to examine the vibration transmission through rolling element bearings in geared rotor systems. Current bearing models, based on either ideal boundary conditions for the shaft or purely translational stiffness element description, cannot explain how the vibratory motion may be transmitted from the rotating shaft to the casing. This study clarifies this issue qualitatively and quantitatively by developing a comprehensive bearing stiffness matrix of dimension 6 model for the precision rolling element bearings from basic principles. The proposed bearing formulation is extended to analyze the overall geared rotor system dynamics including casing and mounts. The bearing stiffness matrix is included in discrete system models using lumped parameter and/or dynamic finite element techniques. Eigensolution and forced harmonic response due to rotating mass unbalance or kinematic transmission error excitation for a number of examples are computed.

  19. Rotary shaft seal

    DOEpatents

    Langebrake, C.O.

    1984-01-01

    The invention is a novel rotary shaft seal assembly which provides positive-contact sealing when the shaft is not rotated and which operates with its sealing surfaces separated by a film of compressed ambient gas whose width is independent of the speed of shaft rotation. In a preferred embodiment, the assembly includes a disc affixed to the shaft for rotation therewith. Axially movable, non-rotatable plates respectively supported by sealing bellows are positioned on either side of the disc to be in sealing engagement therewith. Each plate carries piezoelectric transucer elements which are electrically energized at startup to produce films of compressed ambient gas between the confronting surfaces of the plates and the disc. Following shutdown of the shaft, the transducer elements are de-energized. A control circuit responds to incipient rubbing between the plate and either disc by altering the electrical input to the transducer elements to eliminate rubbing.

  20. Rotary shaft seal

    DOEpatents

    Langebrake, Clair O.

    1984-01-01

    The invention is a novel rotary shaft seal assembly which provides positive-contact sealing when the shaft is not rotated and which operates with its sealing surfaces separated by a film of compressed ambient gas whose width is independent of the speed of shaft rotation. In a preferred embodiment, the assembly includes a disc affixed to the shaft for rotation therewith. Axially movable, non-rotatable plates respectively supported by sealing bellows are positioned on either side of the disc to be in sealing engagement therewith. Each plate carries piezoelectric transducer elements which are electrically energized at startup to produce films of compressed ambient gas between the confronting surfaces of the plates and the disc. Following shutdown of the shaft, the transducer elements are de-energized. A control circuit responds to incipient rubbing between the plate and either disc by altering the electrical input to the transducer elements to eliminate rubbing.

  1. Cylindrical bearing analysis

    NASA Technical Reports Server (NTRS)

    Kleckner, R. J.; Pirvics, J.

    1981-01-01

    Program CYBEAN computes behavior of rolling-element bearings including effects of bearing geometry, shaft misalinement, and temperature. Accurate assessment is possible for various outer-ring and housing configurations. CYBEAN is structured for coordinated execution of modules that perform specific analytical tasks. It is written in FORTRAN IV for use on the UNIVAC 1100/40 computer.

  2. Passive Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    Studer, P. A.

    1983-01-01

    Magnetic bearing for limited rotation devices requires no feedback control system to sense and correct shaft position. Passive Magnetic Torsion Bearing requires no power supply and has no rubbing parts. Torsion wire restrains against axial instability. Magnetic flux geometry chosen to assure lateral stability with radial restoring force that maintains alignment.

  3. A cluster of three cases of trichinellosis linked to bear meat consumption in the Arctic.

    PubMed

    Dupouy-Camet, Jean; Yera, Hélène; Dahane, Naïma; Bouthry, Elise; Kapel, Christian M O

    2016-05-01

    We report here three cases of trichinellosis due to polar bear meat consumption in East Greenland. In the past 20 years, 31 cases of trichinellosis have been reported in French travellers to the Arctic (North Quebec, Nunavut and Greenland) who consumed undercooked meat from black, brown, or polar bears. If local communities are increasingly becoming aware of the risk of trichinellosis, travellers visiting regions where bear meat is consumed should be informed of the risk of eating raw or non-heat-processed meats. © International Society of Travel Medicine, 2016. All rights reserved. Published by Oxford University Press. For permissions, please e-mail: journals.permissions@oup.com.

  4. Cam shaft with expanded hollow shaft

    SciTech Connect

    Hughes, R.W.; Brisson, R.H.; Brisson, G.R.

    1987-09-15

    This patent describes a camshaft having lobes with irregularly shaped apertures spaced along the longitudinal axis of a hollow tubular shaft. The lobes are orientated radially and axially in predetermined positions along the hollow tubular shaft. The camshaft is characterized by the walls of the hollow shaft expanded outwardly into aperture portions in irregular engagement with the interior of the apertures of the lobes and the walls expanded outwardly radially farther into ballooned portions between adjacent lobes to create corresponding outside and inside shoulders extending between the aperture and ballooned portions. The outside shoulders are disposed immediately adjacent and abutting each side of the lobes circumferentially about the apertures therein to secure the lobes axially upon the shaft, the inside shoulders disposed directly opposite the outside shoulders to that shoulder extend annularly about each end of each of the apertures and the ballooned portions extend between shoulders at adjacent lobes, the exterior circumferences of the lobes being furnished to closer tolerances than the interior apertures and the exterior surfaces of the lobes being positioned radially relative to the longitudinal axis with the radial positions of the interior apertures being offset among adjacent lobes.

  5. Fluid lubricated bearing assembly

    DOEpatents

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

    1976-01-01

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

  6. ‘Neanderthal bone flutes’: simply products of Ice Age spotted hyena scavenging activities on cave bear cubs in European cave bear dens

    PubMed Central

    Diedrich, Cajus G.

    2015-01-01

    Punctured extinct cave bear femora were misidentified in southeastern Europe (Hungary/Slovenia) as ‘Palaeolithic bone flutes’ and the ‘oldest Neanderthal instruments’. These are not instruments, nor human made, but products of the most important cave bear scavengers of Europe, hyenas. Late Middle to Late Pleistocene (Mousterian to Gravettian) Ice Age spotted hyenas of Europe occupied mainly cave entrances as dens (communal/cub raising den types), but went deeper for scavenging into cave bear dens, or used in a few cases branches/diagonal shafts (i.e. prey storage den type). In most of those dens, about 20% of adult to 80% of bear cub remains have large carnivore damage. Hyenas left bones in repeating similar tooth mark and crush damage stages, demonstrating a butchering/bone cracking strategy. The femora of subadult cave bears are intermediate in damage patterns, compared to the adult ones, which were fully crushed to pieces. Hyenas produced round–oval puncture marks in cub femora only by the bone-crushing premolar teeth of both upper and lower jaw. The punctures/tooth impact marks are often present on both sides of the shaft of cave bear cub femora and are simply a result of non-breakage of the slightly calcified shaft compacta. All stages of femur puncturing to crushing are demonstrated herein, especially on a large cave bear population from a German cave bear den. PMID:26064624

  7. [Femoral shaft fractures in children].

    PubMed

    Dietz, H-G; Schlickewei, W

    2011-05-01

    Femoral shaft fractures in children represent 1.5% of all fractures in childhood. Up to the age of 4 years, conservative treatment in a hip spica or short-term overhead traction is the therapy of choice. Femoral shaft fractures between the age of 5 and 16 years should be treated surgically. In over 90% of these cases elastic stable intramedullary nailing (ESIN) is the premier treatment option. Additional end caps can be used for unstable fractures and in length discrepancy. The external fixator and the locking plate are reserved for fractures with severe soft tissue injuries, vascular problems and some specific situations mentioned later on. By adhering to these standards good results can be achieved with a low complication rate.

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

    SciTech Connect

    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.

  9. Methods and systems for micro bearings

    DOEpatents

    Stalford, Harold L.

    2012-10-09

    A micro drive assembly may comprise a substrate, a micro shall oriented in-plane with the substrate and at least one micro bearing to support rotation of the micro shaft. The micro shaft and micro bearing may be in or less than the micrometer domain.

  10. Magnetic Bearings Would Increase Pump Efficiency

    NASA Technical Reports Server (NTRS)

    Studer, P. A.

    1983-01-01

    Active feedback applied to bearings windings compensate for unbalanced forces. Helical-screw rotation compresses and transports gas charges, which subject shafts to forces tend to displace them from their equilibrium positions. Magnetic bearings restore shafts to equilibrium, lowering friction and increasing efficiency.

  11. Magnetic bearing turbomachinery case histories and applications for space related equipment

    NASA Technical Reports Server (NTRS)

    Weise, David A.

    1993-01-01

    The concept of magnetic levitation is not a new one and can be easily traced back to the 1800's. It is only recently, however, that the congruous technologies of electronic control systems, power electronics, and magnetic materials have begun to merge to make the magnetic suspension device a viable product. A brief overview of an active magnetic bearing technology is provided. Case histories of various turbomachinery in North America presently operating on magnetic bearings are reviewed. Finally, projections are made as to the space related machinery that may be benefited by incorporating magnetic bearings into the equipment design.

  12. Fabricated torque shaft

    DOEpatents

    Mashey, Thomas Charles

    2002-01-01

    A fabricated torque shaft is provided that features a bolt-together design to allow vane schedule revisions with minimal hardware cost. The bolt-together design further facilitates on-site vane schedule revisions with parts that are comparatively small. The fabricated torque shaft also accommodates stage schedules that are different one from another in non-linear inter-relationships as well as non-linear schedules for a particular stage of vanes.

  13. Treatment of open tibial shaft fracture with soft tissue and bone defect caused by aircraft bomb--case report.

    PubMed

    Golubović, Zoran; Vidić, Goran; Trenkić, Srbobran; Vukasinović, Zoran; Lesić, Aleksandar; Stojiljković, Predrag; Stevanović, Goran; Golubović, Ivan; Visnjić, Aleksandar; Najman, Stevo

    2010-01-01

    Aircraft bombs can cause severe orthopaedic injuries. Tibia shaft fractures caused by aircraft bombs are mostly comminuted and followed by bone defects, which makes the healing process extremely difficult and prone to numerous complications. The goal of this paper is to present the method of treatment and the end results of treatment of a serious open tibial fracture with soft and bone tissue defects resulting from aircraft bomb shrapnel wounds. A 26-year-old patient presented with a tibial fracture as the result of a cluster bomb shrapnel wound. He was treated applying the method of external bone fixation done two days after wounding, as well as of early coverage of the lower leg soft tissue defects done on the tenth day after the external fixation of the fracture. The external fixator was removed after five months, whereas the treatment was continued by means of functional plaster cast for another two months. The final functional result was good. Radical wound debridement, external bone fixation of the fracture, and early reconstruction of any soft tissue and bone defects are the main elements of the treatment of serious fractures.

  14. Touchdown Ball-Bearing System for Magnetic Bearings

    NASA Technical Reports Server (NTRS)

    Kingsbury, Edward P.; Price, Robert; Gelotte, Erik; Singer, Herbert B.

    2003-01-01

    The torque-limited touchdown bearing system (TLTBS) is a backup mechanical-bearing system for a high-speed rotary machine in which the rotor shaft is supported by magnetic bearings in steady-state normal operation. The TLTBS provides ball-bearing support to augment or supplant the magnetic bearings during startup, shutdown, or failure of the magnetic bearings. The TLTBS also provides support in the presence of conditions (in particular, rotational acceleration) that make it difficult or impossible to control the magnetic bearings or in which the magnetic bearings are not strong enough (e.g., when the side load against the rotor exceeds the available lateral magnetic force).

  15. MULTIPLE SHAFT TOOL HEAD

    DOEpatents

    Colbert, H.P.

    1962-10-23

    An improved tool head arrangement is designed for the automatic expanding of a plurality of ferruled tubes simultaneously. A plurality of output shafts of a multiple spindle drill head are driven in unison by a hydraulic motor. A plurality of tube expanders are respectively coupled to the shafts through individual power train arrangements. The axial or thrust force required for the rolling operation is provided by a double acting hydraulic cylinder having a hollow through shaft with the shaft cooperating with an internally rotatable splined shaft slidably coupled to a coupling rigidly attached to the respectlve output shaft of the drill head, thereby transmitting rotary motion and axial thrust simultaneously to the tube expander. A hydraulic power unit supplies power to each of the double acting cylinders through respective two-position, four-way valves, under control of respective solenoids for each of the cylinders. The solenoids are in turn selectively controlled by a tool selection control unit which in turn is controlled by signals received from a programmed, coded tape from a tape reader. The number of expanders that are extended in a rolling operation, which may be up to 42 expanders, is determined by a predetermined program of operations depending upon the arrangement of the ferruled tubes to be expanded in the tube bundle. The tape reader also supplies dimensional information to a machine tool servo control unit for imparting selected, horizontal and/or vertical movement to the tool head assembly. (AEC)

  16. Measuring Motor-Shaft Clearance And Wobble During Operation

    NASA Technical Reports Server (NTRS)

    Chern, Engmin James

    1996-01-01

    Noncontact proximity sensor, preferably eddy-current liftoff probe, provides realtime measurement of distance and small variations of distance between two mechanical components designed to be maintained at precise, fixed distance. In particular, system intended for use in measuring lateral clearance and variations in lateral clearance (wobble) of motor shaft relative to motor housing while shaft turning. Provides early indication of wear in motor bearings. Rate of rotation also measured.

  17. Simplified installation of thrust bearings

    NASA Technical Reports Server (NTRS)

    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.

  18. Application of hydraulically assembled shaft coupling hubs to large agitators

    SciTech Connect

    Murray, W.E.; Anderson, T.D.; Bethmann, H.K.

    1991-12-31

    This paper describes the basis for and implementation of hydraulically assembled shaft coupling hubs for large tank-mounted agitators. This modification to the original design was intended to minimize maintenance personnel exposure to ionizing radiation and also provide for disassembly capability without damage to shafts or hubs. In addition to realizing these objectives, test confirmed that the modified couplings reduced agitator shaft end runouts approximately 65%, thereby reducing bearing loads and increasing service life, a significant enhancement for a nuclear facility. 5 refs.

  19. Application of hydraulically assembled shaft coupling hubs to large agitators

    SciTech Connect

    Murray, W.E.; Anderson, T.D. ); Bethmann, H.K. )

    1991-01-01

    This paper describes the basis for and implementation of hydraulically assembled shaft coupling hubs for large tank-mounted agitators. This modification to the original design was intended to minimize maintenance personnel exposure to ionizing radiation and also provide for disassembly capability without damage to shafts or hubs. In addition to realizing these objectives, test confirmed that the modified couplings reduced agitator shaft end runouts approximately 65%, thereby reducing bearing loads and increasing service life, a significant enhancement for a nuclear facility. 5 refs.

  20. Blood Pump Bearing System

    NASA Technical Reports Server (NTRS)

    Aber, Gregory S. (Inventor)

    1999-01-01

    Methods and apparatus are provided for a blood pump bearing system within a pump housing to support long-term high-speed rotation of a rotor with an impeller blade having a plurality of individual magnets disposed thereon to provide a small radial air gap between the magnets and a stator of less than 0.025 inches. The bearing system may be mounted within a flow straightener, diffuser, or other pump element to support the shaft of a pump rotor. The bearing system includes a zirconia shaft having a radiused end. The radiused end has a first radius selected to be about three times greater than the radius of the zirconia shaft. The radiused end of the zirconia shaft engages a flat sapphire endstone. Due to the relative hardness of these materials a flat is quickly produced during break-in on the zirconia radiused end of precisely the size necessary to support thrust loads whereupon wear substantially ceases. Due to the selection of the first radius, the change in shaft end-play during pump break-in is limited to a total desired end-play of less than about 0.010 inches. Radial loads are supported by an olive hole ring jewel that makes near line contact around the circumference of the shaft to support high speed rotation with little friction. The width of olive hole ring jewel is small to allow heat to conduct through to thereby prevent heat build-up in the bearing. A void defined by the bearing elements may fill with blood that then coagulates within the void. The coagulated blood is then conformed to the shape of the bearing surfaces.

  1. Blood Pump Bearing System

    NASA Technical Reports Server (NTRS)

    Aber, Gregory S. (Inventor)

    2000-01-01

    An apparatus is provided for a blood pump bearing system within a pump housing to support long-term highspeed rotation of a rotor with an impeller blade having a plurality of individual magnets disposed thereon to provide a small radial air gap between the magnets and a stator of less than 0.025 inches. The bearing system may be mounted within a flow straightener, diffuser, or other pump element to support the shaft of a pump rotor. The bearing system includes a zirconia shaft having a radiused end. The radiused end has a first radius selected to be about three times greater than the radius of the zirconia shaft. The radiused end of the zirconia shaft engages a flat sapphire endstone. Due to the relative hardness of these materials a flat is quickly produced during break-in on the zirconia radiused end of precisely the size necessary to support thrust loads whereupon wear substantially ceases. Due to the selection of the first radius, the change in shaft end-play during pump break-in is limited to a total desired end-play of less than about 0.010 inches. Radial loads are supported by an olive hole ring jewel that makes near line contact around the circumference of the Ir shaft to support big speed rotation with little friction. The width of olive hole ring jewel is small to allow heat to conduct through to thereby prevent heat build-up in the bearing. A void defined by the bearing elements may fill with blood that then coagulates within the void. The coagulated blood is then conformed to the shape of the bearing surfaces.

  2. Tibial shaft stress fractures resulting from placement of navigation tracker pins.

    PubMed

    Hoke, David; Jafari, S Mehdi; Orozco, Fabio; Ong, Alvin

    2011-04-01

    The use of navigation during joint arthroplasty is believed to allow better placement of components. Gross fracture or stress fracture through navigation tracker pin placement is a complication reported in the literature. This case series presents details of stress fracture of tibial shaft through navigation pin track in 3 patients of 220 cases who underwent total knee arthroplasty at our institution. All the fractures eventually healed after a course of protected weight bearing. As a result, we use smaller-diameter self-tapping and self-drilling pins routinely and avoid placement of pins in the diaphysis and ensure that pins are inserted in different plains during insertion into metaphysis.

  3. An autopsy case related to a terrorist attack using a ball-bearing bomb.

    PubMed

    Takamiya, Masataka; Biwasaka, Hitoshi; Niitsu, Hisae; Saigusa, Kiyoshi; Aoki, Yasuhiro

    2009-03-01

    We encountered an autopsy case related to a terrorist attack using a ball-bearing bomb. The decedent was a 51-year-old male without significant medical histories. During dinner in a restaurant, the perpetrator suddenly exploded a ball-bearing bomb, the blast from which blew the victim off his chair. The victim was found to be unresponsive, and pronounced dead. X-ray photographs taken before autopsy revealed six spherical shadows. Three penetrating wounds in the head, one in the neck and chest, and two in the left upper arm were observed in vivo. Six projectiles recovered from the body were identified as ball-bearings, one of which traveled through the midbrain, diencephalon, and left temporal lobe. Although blast injuries and penetrating wounds are often combined in bomb attack victims, penetrating brain injury would be the cause of death in this case. Lethal injuries to major organs can thus occur even though the destructive force of a ball-bearing bomb is weak. X-ray films were informative for detecting the ball-bearings in this case, suggesting that autopsy imaging is essential in cases of terrorism victims.

  4. Thin film superconductor magnetic bearings

    DOEpatents

    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.

  5. Sinkhole hazard assessment in the area of abandoned mining shaft basing on microgravity survey and modelling - Case study from the Upper Silesia Coal Basin in Poland

    NASA Astrophysics Data System (ADS)

    Kotyrba, Andrzej; Kortas, Łukasz

    2016-07-01

    The article describes the results of a gravimetric survey conducted in the area of an abandoned mining shaft located on the premises of the liquidated "Porąbka-Klimontów" coal mine in Sosnowiec - southern Poland. After cessation of its exploitation in the past, the shaft has probably only been protected by placing a slab on a concrete pit-bank without commencing the proper liquidation. The aim of the survey was to determine whether the shaft had been backfilled and what is the condition of the rock mass where it gets in contact with the shaft barrel. In the interpretation of the Bouguer anomaly map, a forward modelling of gravity effect generated by an empty mineshaft has been used in order to eliminate its influence on the local gravitational field. That approach to survey data analysis allowed to assess not only the type of the shaft's filling but also the changes in the rock mass structure around it. The results allowed planning an adequate type of works aiming to secure the surface from potential sinkhole deformations resulting from the shaft lining collapse or wash out of the soil into the shaft barrel.

  6. Vibration transmission through rolling element bearings. III - Geared rotor system studies

    NASA Technical Reports Server (NTRS)

    Lim, T. C.; Singh, R.

    1991-01-01

    The bearing matrix formulations proposed by Lim and Singh (1990) are extended to analyze the overall dynamics of a geared rotor system which includes a spur gear pair, shafts, rolling-element bearings, a motor, a load, a casing, and flexible or rigid mounts. For this purpose, discrete vibration models are developed and used to predict vibration transmission through the bearings and to investigate the effects of the bearing, casing, and mount dynamics on the dynamic characteristics of the internal rotating system. Analytical predictions show that the theory is capable of predicting the bearing and mount moment transmissibilities in addition to the force transmissibilities. The predicted flexural vibrations of the casing plate are in good agreement with measurements conducted on an experimental set-up that consisted of a high-precision beam and pinion, and four identical rolling element bearings contained in a flexible casing mounted rigidly on a massive foundation.

  7. Vibration transmission through rolling element bearings. III - Geared rotor system studies

    NASA Technical Reports Server (NTRS)

    Lim, T. C.; Singh, R.

    1991-01-01

    The bearing matrix formulations proposed by Lim and Singh (1990) are extended to analyze the overall dynamics of a geared rotor system which includes a spur gear pair, shafts, rolling-element bearings, a motor, a load, a casing, and flexible or rigid mounts. For this purpose, discrete vibration models are developed and used to predict vibration transmission through the bearings and to investigate the effects of the bearing, casing, and mount dynamics on the dynamic characteristics of the internal rotating system. Analytical predictions show that the theory is capable of predicting the bearing and mount moment transmissibilities in addition to the force transmissibilities. The predicted flexural vibrations of the casing plate are in good agreement with measurements conducted on an experimental set-up that consisted of a high-precision beam and pinion, and four identical rolling element bearings contained in a flexible casing mounted rigidly on a massive foundation.

  8. Shaft Position Optical Sensor

    NASA Technical Reports Server (NTRS)

    Blumenstock, Kenneth A. (Inventor); Hakum, Claef F. (Inventor); Johnson, Clarence S. (Inventor)

    2001-01-01

    The present invention is an optical sensor that senses the movement of a shaft. Detection of radial movement is made when a portion of light incident on the shaft sensor-target is blocked. For detection of axial movement, a disk with flat surface is mounted and used to block a portion of light. The variation in the amount of light allowed to pass through is a measure of the position of the shaft. As proposed by this invention, significant improvement is made with respect to sensitivity and linearity of the system when the light is permanently partially blocked. To accomplish this goal this invention adds a boss to the system. To eliminate possible drift of system performance due to LED degradation or temperature variation, a feedback feature is added to the system.

  9. Turbocharger bearing retention and lubrication system

    SciTech Connect

    Gutknecht, D.A.

    1991-12-31

    This patent describes exhausts gas driven turbocharger. It comprises a housing, a shaft within the housing having a longitudinal axis of rotation and a pair of ends, a compressor wheel mounted within the housing on one end of the shaft for rotation therewith, a turbine wheel mounted within the housing on the other end of the shaft for rotation therewith, means for communicating air to the compressor wheel, means for communicating exhaust gas to the turbine wheel to cause the latter to rotate the shaft and the compressor wheel mounted thereon to compress the air communicated to the compressor wheel, and bearing means mounting the shaft for rotation relative to the housing, the bearing means including a bearing outer ring, a bearing inner ring, and ball bearing elements supporting the bearing outer ring on the bearing inner ring, a bearing locating aperture in the bearing outer ring, and an elongated bearing location pin having a longitudinal axis of symmetry extending transversely to the longitudinal axis of the shaft.

  10. [Fractures of the shaft of the femur].

    PubMed

    Lögters, T; Windolf, J; Flohé, S

    2009-07-01

    The femur is the largest, longest and strongest bone in the human skeleton. Fractures of the shaft of the femur can result from high energy as well as low energy trauma and 30% of patients have multiple injuries. In the clinical diagnostic special attention must be paid to the peripheral neurovascular status as well as the possibility of a compartment syndrome. Fractures of the femur shaft are defined according to the AO classification. Treatment is as a rule operative, except for children up the end of 4 years old. Medullary nailing is nowadays the method of choice and the nails can be implanted in an anterograde or retrograde direction. The introduction of nails after boring out the medullar is associated with an increased healing rate in comparison to non-boring techniques. Various techniques are available for the often promising method of repositioning and the intraoperative controls. Plating is reserved only for special situations. External fixation is of great value in adults for temporary fixation of fractures of the femur shaft. Full weight bearing is possible immediately following the operation depending on the type of fracture and method of treatment. Uncomplicated fracture healing does not result in a reduction in the ability to work. Despite the generally good prognosis and improvement in design and technology of implants, fractures of the femur shaft still represent a special challenge for the treating casualty surgeon.

  11. Case-hardening medium carbon steel for tough and long life bearing under severe lubrication conditions

    SciTech Connect

    Furumura, Kyozaburo; Murakami, Yasuo; Abe, Tsutomu

    1998-12-31

    It is known these days that case-hardening bearings have a longer life than through-hardening ones under severe lubrication conditions (i.e., mixing-in of foreign particles in the lubrication oil). To explain this fact, the authors first presented the mechanism of stress relaxation at the debris dent edge. According to test results, it was found that both retained austenite and hardness are the most important factors for a longer life material. Such material has a longer life even under boundary lubrication conditions. Since a sufficient EHL oil film does not form under boundary lubrication conditions, metal contact occurs. The resulting damage is called peeling and it decreases the bearing life. To realize ideal case hardening material for bearings, a new carbo-nitride heat treatment has been developed. Normally, it is extremely difficult to obtain a sufficient case depth using a traditional carbo-nitride heat treatment process. As an alternate, medium carbon steel was studied. The application of newly developed medium carbon steel has not only proved to make the creation of a sufficient case depth easier, but also provided economic benefits. Based on results from testing both the dimensional stability and fracture toughness, newly developed medium carbon steel can be used for case-hardening bearings.

  12. Gravity in a Mine Shaft.

    ERIC Educational Resources Information Center

    Hall, Peter M.; Hall, David J.

    1995-01-01

    Discusses the effects of gravity, local density compared to the density of the earth, the mine shaft, centrifugal force, and air buoyancy on the weight of an object at the top and at the bottom of a mine shaft. (JRH)

  13. Gravity in a Mine Shaft.

    ERIC Educational Resources Information Center

    Hall, Peter M.; Hall, David J.

    1995-01-01

    Discusses the effects of gravity, local density compared to the density of the earth, the mine shaft, centrifugal force, and air buoyancy on the weight of an object at the top and at the bottom of a mine shaft. (JRH)

  14. Vibration Control in Turbomachinery Using Active Magnetic Journal Bearings

    NASA Technical Reports Server (NTRS)

    Knight, Josiah D.

    1996-01-01

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

  15. Magnetic translator bearings

    NASA Technical Reports Server (NTRS)

    Hockney, Richard L. (Inventor); Downer, James R. (Inventor); Eisenhaure, David B. (Inventor); Hawkey, Timothy J. (Inventor); Johnson, Bruce G. (Inventor)

    1990-01-01

    A magnetic bearing system for enabling translational motion includes a carriage and a shaft for movably supporting the carriage; a first magnetic bearing fixed to one of the carriage and shaft and slidably received in a first channel of the other of the carriage and shaft. The first channel is generally U shaped with two side walls and a back wall. The magnetic bearing includes a pair of spaced magnetic pole pieces, each pole piece having a pair of electromagnetic coils mounted on poles on opposite ends of the pole piece proximate the side walls, and a third electromagnetic coil mounted on a pole of the pole piece proximate the backwall; a motion sensor for sensing translational motion along two axes and rotationally about three axes of the carriage and shaft relative to each other; and a correction circuit responsive to the sensor for generating a correction signal to drive the coils to compensate for any misalignment sensed between the carriage and the shaft.

  16. Acoustical Measurement Of Mine-Shaft Length

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S.

    1988-01-01

    Acoustical system proposed to measure depth of a "blind" shaft. Acoustic wave guided by shaft and provides estimate of shaft length, from which volume estimated. Acoustic-generator system determines resonant-frequency difference to measure shaft length.

  17. Shaft seal system

    DOEpatents

    Kapich, Davorin D.

    1985-01-01

    A shaft seal system is disclosed for isolating two regions of different fluid mediums through which a rotatable shaft extends. The seal system includes a seal housing through which the shaft extends and which defines an annular land and an annular labyrinth both of which face on the shaft so that each establishes a corresponding fluid sealing annulus. A collection cavity is formed in communication with the annular sealing spaces, and fluids compatible with the fluids in each of the two regions to be isolated are introduced, respectively, into the annular sealing spaces and collected in the collection cavity from which the fluid mixture is removed and passed to a separator which separates the fluids and returns them to their respective annular sealing spaces in a recycling manner. In the illustrated embodiment, the isolated fluid mediums comprise a liquid region and a gas region. Gas is removed from the gas region and passed through a purifier and a gas pump operative to introduce the purified gas through the labyrinth sealing annulus to the collection cavity. After passing to the separator, the separated gas is passed through a dryer from which the dried gas is caused to pass through the labyrinth sealing annulus into the collection cavity independently of the purified gas so as to insure isolation of the gas region in the event of sealing gas pump malfunction.

  18. Polygonal shaft hole rotor

    DOEpatents

    Hussey, John H.; Rose, John Scott; Meystrik, Jeffrey J.; White, Kent Lee

    2001-01-23

    A laminated rotor for an induction motor has a plurality of ferro-magnetic laminations mounted axially on a rotor shaft. Each of the plurality of laminations has a central aperture in the shape of a polygon with sides of equal length. The laminations are alternatingly rotated 180.degree. from one another so that the straight sides of the polygon shaped apertures are misaligned. As a circular rotor shaft is press fit into a stack of laminations, the point of maximum interference occurs at the midpoints of the sides of the polygon (i.e., at the smallest radius of the central apertures of the laminations). Because the laminates are alternatingly rotated, the laminate material at the points of maximum interference yields relatively easily into the vertices (i.e., the greatest radius of the central aperture) of the polygonal central aperture of the next lamination as the shaft is inserted into the stack of laminations. Because of this yielding process, the amount of force required to insert the shaft is reduced, and a tighter fit is achieved.

  19. The series hybrid bearing - A new high speed bearing concept.

    NASA Technical Reports Server (NTRS)

    Anderson, W. J.; Fleming, D. P.; Parker, R. J.

    1971-01-01

    The series-hybrid bearing couples a fluid-film bearing with a rolling-element bearing such that the rolling-element bearing inner race runs at a fraction of shaft speed. A series-hybrid bearing was analyzed and experiments were run at thrust loads from 100 to 300 lb and speeds from 4000 to 30,000 rpm. Agreement between theoretical and experimental speed sharing was good. The lowest speed ratio (ratio of ball bearing inner-race speed to shaft speed) obtained was 0.67. This corresponds to an approximate reduction in DN value of 1/3. For a ball bearing in a 3 million DN application, fatigue life would theoretically be improved by a factor as great as 8.

  20. Dynamics of High-Speed Rotors Supported in Sliding Bearings

    NASA Astrophysics Data System (ADS)

    Šimek, J.; Svoboda, R.

    The higher the operating speed, the more serious are problems with rotor stability. Three basic groups of rotors are analyzed and some methods of suppressing instability are shown. In the first group are classical elastic rotors supported in hydrodynamic bearings. Practically all high-speed rotors now run in tilting pad bearings, which are inherently stable, but in specific conditions even tiling pad bearings may not ensure rotor stability. The second group is composed of combustion engines turbocharger rotors, which are characteristic by heavy impellers at both overhung ends of elastic shaft. These rotors are in most cases supported in floating ring bearings, which bring special features to rotor behaviour. The third group of rotors with gas bearings exhibits special features.

  1. Evaluation of steel shafts for magnetostrictive torque sensors (abstract)

    SciTech Connect

    Koga, F.; Yoshida, K.; Sasada, I.

    1997-04-01

    Based on the magnetostrictive effect in steel, a robust, noncontacting shaft torque sensor can be obtained. A fundamental problem is compatibility between mechanical strength required for a shaft and a magnetic one needed for a torque sensor. To find shaft material accommodating these two requirements, we investigated basic characteristics, such as hysteresis, linearity, and zero-level fluctuation associated with shaft rotation, of the magnetostrictive torque sensor for various nickel chromium molybdenum steel shafts (SNCM in Japanese Industrial Standard) subjected to case hardening. We prepared three kinds of shafts of 25 mm in diameter: SNCM 420 (Ni=1.69{percent}, C=0.2{percent}), SNCM 616 (Ni=2.91{percent}, C=0.15{percent}), and SNCM 447 (Ni=1.67{percent}, C=0.49{percent}). Shafts of the first two materials were carburized, whereas those of the last one were quenched. We used a magnetic head-type torque sensor consisting of a pair of cross-coupled figure-eight coils (14 turn). The hysteresis in the input{endash}output relationship was measured for the excitation current from 0.1 to 1.0 A at 60 kHz. The hysteresis of the SNCM 420 shaft changes from negative to positive with the increase in excitation current and that of the SNCM 616 shaft decreases monotonically but never reaches zero, whereas that of the SNCM 447 shaft exhibits minimum. The smallest values obtained are nearly zero for the SNCM 420 shaft at 0.3 A, 1.5{percent}/(full scale (FS)=400 Nm) for the SNCM 616 shaft at 1.0 A and 0.7{percent}/FS for the SNCM 447 shaft at 0.8 A, respectively. The linearity measured for the SNCM 420 shaft, which has the smallest hysteresis of the three, at 0.3 A and 60 kHz was virtually straight for the applied torque range {minus}400{endash}400 Nm and 0.8{percent} of nonlinearity error for the range {minus}1000{endash}1000 Nm. The zero-level fluctuation was measured for the SNCM 420 shaft by rotating the shaft without applying torque. (Abstract Truncated)

  2. Synthetic fiber from a teddy bear causing keratitis and conjunctival granuloma: case report

    PubMed Central

    2011-01-01

    Background To report a case of keratitis and a case of conjunctivitis caused by synthetic fibers from toy teddy bears. Case presentation Case stories with histopathological analysis. 1) A two-year-old girl developed a severe case of keratitis and corneal ulceration. The initial treatment with various antibiotics gave no improvement and eventually the patient developed spontaneous perforation of the cornea. The corneal swabs contained no bacteria or fungi. Corneal grafting was performed and the corneal button was sent for histopathological examination. 2) A five-year-old girl presented with ocular irritation in her left eye. Examination revealed a conjunctival granuloma in the inferior fornix. The lesion was excised and histopathologically examined. Results Microscopy revealed synthetic fibers embedded in the cornea and in the conjunctival granuloma. The diagnosis was confirmed by demonstration of marked birefringence of the synthetic fibers. Microscopical examination of synthetic fibers from two different types of fur (whiskers and face hairs) from the two-year-old girl's teddy bear was performed. Hairs from the face of the teddy bear were morphologically and microscopically identical with the fibers causing the severe corneal ulceration in the two-year-old girl. Conclusions Doctors should especially in small children be aware of the risk of ocular consequences of close exposure of synthetic fibers from stuffed toy animals. Corneal ulceration, clinically presenting as corneal infection with negative culturing and staining, should lead to a different clinical strategy and treatment. The treatment of conjunctival synthetic fiber granuloma is excision and antibiotic eye drops. PMID:21689446

  3. Using the sensors of shaft position for simulation of misalignments of shafting supports of turbounits

    NASA Astrophysics Data System (ADS)

    Kumenko, A. I.; Kostyukov, V. N.; Kuz'minykh, N. Yu.; Timin, A. V.; Boichenko, S. N.

    2017-09-01

    Examples of using the method developed for the earlier proposed concept of the monitoring system of the technical condition of a turbounit are presented. The solution methods of the inverse problem—the calculation of misalignments of supports based on the measurement results of positions of rotor pins in the borings of bearings during the operation of a turbounit—are demonstrated. The results of determination of static responses of supports at operation misalignments are presented. The examples of simulation and calculation of misalignments of supports are made for the three-bearing "high-pressure rotor-middle-pressure rotor" (HPR-MPR) system of a turbounit with 250 MW capacity and for 14-supporting shafting of a turbounit with 1000 MW capacity. The calculation results of coefficients of the stiffness matrix of shaftings and testing of methods for solving the inverse problem by modeling are presented. The high accuracy of the solution of the inverse problem at the inversion of the stiffness matrix of shafting used for determining the correcting centerings of rotors of multisupporting shafting is revealed. The stiffness matrix can be recommended to analyze the influence of displacements of one or several supports on changing the support responses of shafting of the turbounit during adjustment after assembling or repair. It is proposed to use the considered methods of evaluation of misalignments in the monitoring systems of changing the mutual position of supports and centerings of rotors by half-couplings of turbounits, especially for seismically dangerous regions and regions with increased sagging of foundations due to watering of soils.

  4. Investigation of Pressurized Wave Bearings

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

    The wave bearing has been pioneered and developed by Dr. Dimofte over the past several years. This bearing will be the main focus of this research. It is believed that the wave bearing offers a number of advantages over the foil bearing, which is the bearing that NASA is currently pursuing for turbomachinery applications. The wave bearing is basically a journal bearing whose film thickness varies around the circumference approximately sinusoidally, with usually 3 or 4 waves. Being a rigid geometry bearing, it provides precise control of shaft centerlines. The wave profile also provides good load capacity and makes the bearing very stable. Manufacturing techniques have been devised that should allow the production of wave bearings almost as cheaply as conventional full-circular bearings.

  5. Dynamic tester for rotor seals and bearings

    NASA Technical Reports Server (NTRS)

    Vonpragenau, George L. (Inventor)

    1993-01-01

    A dynamic tester for testing vibration damping seals and bearings is constructed having a hollow shaft extending through the seal or bearing, with the shaft internally supported at each end by fluid bearings on hollow bosses connected to an interior of an enclosure, with no rolling members connected to the shaft is described. A high pressure working fluid is forced through the hollow bosses to operate the bearings. Additionally, the shaft is provided with a reaction turbine that angularly vents a portion of the high pressure working fluid in order to rotate the shaft at high speed, up to 40,000 rpm. The seal or bearing is mounted in a bushing, in turn supported by rods to a shaking device that vibrates the seal or bearing as the shaft is rotated. A plurality of proximity sensors are mounted from outside the enclosure to sense shaft and seal bushing vibrations, and a plurality of pressure ports are disposed in the enclosure to allow sensing of dynamic and static pressures of the testing apparatus.

  6. Rotary shaft sealing assembly

    DOEpatents

    Dietle, Lannie L.; Schroeder, John E.; Kalsi, Manmohan S.; Alvarez, Patricio D.

    2010-09-21

    A rotary shaft sealing assembly in which a first fluid is partitioned from a second fluid in a housing assembly having a rotary shaft located at least partially within. In one embodiment a lip seal is lubricated and flushed with a pressure-generating seal ring preferably having an angled diverting feature. The pressure-generating seal ring and a hydrodynamic seal may be used to define a lubricant-filled region with each of the seals having hydrodynamic inlets facing the lubricant-filled region. Another aspect of the sealing assembly is having a seal to contain pressurized lubricant while withstanding high rotary speeds. Another rotary shaft sealing assembly embodiment includes a lubricant supply providing a lubricant at an elevated pressure to a region between a lip seal and a hydrodynamic seal with a flow control regulating the flow of lubricant past the lip seal. The hydrodynamic seal may include an energizer element having a modulus of elasticity greater than the modulus of elasticity of a sealing lip of the hydrodynamic seal.

  7. Rotary shaft sealing assembly

    DOEpatents

    Dietle, Lannie L; Schroeder, John E; Kalsi, Manmohan S; Alvarez, Patricio D

    2013-08-13

    A rotary shaft sealing assembly in which a first fluid is partitioned from a second fluid in a housing assembly having a rotary shaft located at least partially within. In one embodiment a lip seal is lubricated and flushed with a pressure-generating seal ring preferably having an angled diverting feature. The pressure-generating seal ring and a hydrodynamic seal may be used to define a lubricant-filled region with each of the seals having hydrodynamic inlets facing the lubricant-filled region. Another aspect of the sealing assembly is having a seal to contain pressurized lubricant while withstanding high rotary speeds. Another rotary shaft sealing assembly embodiment includes a lubricant supply providing a lubricant at an elevated pressure to a region between a lip seal and a hydrodynamic seal with a flow control regulating the flow of lubricant past the lip seal. The hydrodynamic seal may include an energizer element having a modulus of elasticity greater than the modulus of elasticity of a sealing lip of the hydrodynamic seal.

  8. DETAIL SHOWING THE STERN TUBE, PROPELLOR SHAFT AND RELATED EQUIPMENT ...

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

    DETAIL SHOWING THE STERN TUBE, PROPELLOR SHAFT AND RELATED EQUIPMENT IN THE LOWER MOTOR ROOM. NOTE THE WORM-WHEEL TURNING GEAR AT CENTER, AND THE KINGBURY THRUST BEARING IN THE FOREGROUND IMMEDIATELY FOREWORD OF THE WORM-WHEEL GEAR. NOTE ALSO THE 50-POUND IRON BALLAST BLOCKS STACKED BETWEEN FRAMES. - Lightship 116, Pier 3, Inner Harbor, Baltimore, Independent City, MD

  9. Methods of Erecting Supports in Mine Shafts,

    DTIC Science & Technology

    2014-09-26

    erecting permanent supports in mine shafts * which are sunk with the pre-freezing of the rock and where a concrete * casing is sunk parallel with the...carried out independent of the construction of a concrete casing * with a space left which is filled with sand or gravel. This provides for an...which is sunk a concrete casing and then tubbing is erected in an upward direction with a space left which is filled with sand or gravel. In the

  10. Synthetic fiber from a teddy bear causing keratitis and conjunctival granuloma: case report.

    PubMed

    Farooq, Mohammed K; Prause, Jan U; Heegaard, Steffen

    2011-06-20

    To report a case of keratitis and a case of conjunctivitis caused by synthetic fibers from toy teddy bears. Case stories with histopathological analysis. 1) A two-year-old girl developed a severe case of keratitis and corneal ulceration. The initial treatment with various antibiotics gave no improvement and eventually the patient developed spontaneous perforation of the cornea. The corneal swabs contained no bacteria or fungi. Corneal grafting was performed and the corneal button was sent for histopathological examination. 2) A five-year-old girl presented with ocular irritation in her left eye. Examination revealed a conjunctival granuloma in the inferior fornix. The lesion was excised and histopathologically examined. Microscopy revealed synthetic fibers embedded in the cornea and in the conjunctival granuloma. The diagnosis was confirmed by demonstration of marked birefringence of the synthetic fibers. Microscopical examination of synthetic fibers from two different types of fur (whiskers and face hairs) from the two-year-old girl's teddy bear was performed. Hairs from the face of the teddy bear were morphologically and microscopically identical with the fibers causing the severe corneal ulceration in the two-year-old girl. Doctors should especially in small children be aware of the risk of ocular consequences of close exposure of synthetic fibers from stuffed toy animals. Corneal ulceration, clinically presenting as corneal infection with negative culturing and staining, should lead to a different clinical strategy and treatment. The treatment of conjunctival synthetic fiber granuloma is excision and antibiotic eye drops.

  11. Kinematics Simulation of the Cardan Shaft for Investigation of the Cardan Error in Catia V5

    NASA Astrophysics Data System (ADS)

    Hajdu, Štefan; Rolník, Ladislav; Švoš, Juraj

    2016-12-01

    The goal of this paper is the creation of kinematic systems of the cardan shaft in the CAD/CAM/CAE system CATIA V5 and analysis of three cases of assembly to determine upon which, angular accelerations had been observed between the input driving shaft, central cardan shaft and output driven shaft. The scientific result of this paper was to confirm the presence of cardan error and how this type of error can be successfully eliminated.

  12. Magnetic bearings give new meaning to spin control

    SciTech Connect

    Swanekamp, R.

    1996-09-01

    In the past, their large size, high cost, and complicated controls ruled out practical application. But the last magnetic bearings are making commercial inroads in the natural-gas industry. Demonstration projects, limited in duration and results, may secure acceptance by powerplants, too. Alternatives to conventional oil-lubricated bearings have appeared from time to time. Steam- and gas-lubricated varieties are examples. But except for a few niche applications, no alternatives have garnered commercial acceptance. A relatively recent development, magnetic bearings, may finally break the mold. Potential benefits are enticing: A shaft suspended in air and positioned against end thrust by magnetic forces suffers negligible friction, thereby lowering starting torque and power losses; bearing wear, and in some cases, shaft seals, are eliminated, extending service life and reducing maintenance; repairs largely consist of a technician replacing a card in the control system, as opposed to a mechanical crew tearing down and replacing a conventional bearing; imbalance forces are canceled or controlled without transmitting large forces to the foundation; lubricants, which can contaminate process fluids and pose fire hazards, are eliminated or substantially reduced. These benefits have been realized for years in centrifuges, machine tools, and space applications. Now magnetic bearings are making substantial inroads in large-scale, industrial turbo-machinery, led by commercial use in gas pipeline compressors, along with demonstration projects on powerplant pumps and fans.

  13. Development of small bore, high speed tapered roller bearing

    NASA Technical Reports Server (NTRS)

    Morrison, F. R.; Gassel, S. S.; Bovenkerk, R. L.

    1981-01-01

    The performance of four rolling bearing configurations for use on the input pinion shaft of a proposed commercial helicopter transmission was evaluated. The performance characteristics of a high speed tapered roller bearing operating under conditions comparable to those existing at this input pinion shaft were defined. The tapered roller bearing shaft support configuration was developed for the gearbox using commercially available bearing designings. The configuration was optimized and interactive thermomechanically system analyzed. Automotive pinion quality tapered roller bearings were found to be reliable under load and speed conditions in excess of those anticipated in the helicopter transmission. However, it is indicated that the elastohydrodynamic lubricant films are inadequate.

  14. Gerotor and bearing system for whirling mass orbital vibrator

    DOEpatents

    Brett, James Ford; Westermark, Robert Victor; Turner, Jr., Joey Earl; Lovin, Samuel Scott; Cole, Jack Howard; Myers, Will

    2007-02-27

    A gerotor and bearing apparatus for a whirling mass orbital vibrator which generates vibration in a borehole. The apparatus includes a gerotor with an inner gear rotated by a shaft having one less lobe than an outer gear. A whirling mass is attached to the shaft. At least one bearing is attached to the shaft so that the bearing engages at least one sleeve. A mechanism is provided to rotate the inner gear, the mass and the bearing in a selected rotational direction in order to cause the mass, the inner gear, and the bearing to backwards whirl in an opposite rotational direction. The backwards whirling mass creates seismic vibrations.

  15. Relation Between Residual and Hoop Stresses and Rolling Bearing Fatigue Life

    NASA Technical Reports Server (NTRS)

    Oswald, Fred B.; Zaretsky, Erwin V.; Poplawski, Joseph V.

    2015-01-01

    Rolling-element bearings operated at high speed or high vibration may require a tight interference fit between the bore of the bearing and shaft to prevent rotation of the bearing bore around the shaft and fretting damage at the interfaces. Previous work showed that the hoop stresses resulting from tight interference fits can reduce bearing lives by as much as 65 percent. Where tight interference fits are required, case-carburized steel such as AISI 9310 or M50 NiL is often used because the compressive residual stresses inhibit subsurface crack formation and the ductile core inhibits inner-ring fracture. The presence of compressive residual stress and its combination with hoop stress also modifies the Hertz stress-life relation. This paper analyzes the beneficial effect of residual stresses on rolling-element bearing fatigue life in the presence of high hoop stresses for three bearing steels. These additional stresses were superimposed on Hertzian principal stresses to calculate the inner-race maximum shearing stress and the resulting fatigue life of the bearing. The load-life exponent p and Hertz stress-life exponent n increase in the presence of compressive residual stress, which yields increased life, particularly at lower stress levels. The Zaretsky life equation is described and is shown to predict longer bearing lives and greater load- and stress-life exponents, which better predicts observed life of bearings made from vacuum-processed steel.

  16. Not accounting for interindividual variability can mask habitat selection patterns: a case study on black bears.

    PubMed

    Lesmerises, Rémi; St-Laurent, Martin-Hugues

    2017-09-09

    Habitat selection studies conducted at the population scale commonly aim to describe general patterns that could improve our understanding of the limiting factors in species-habitat relationships. Researchers often consider interindividual variation in selection patterns to control for its effects and avoid pseudoreplication by using mixed-effect models that include individuals as random factors. Here, we highlight common pitfalls and possible misinterpretations of this strategy by describing habitat selection of 21 black bears Ursus americanus. We used Bayesian mixed-effect models and compared results obtained when using random intercept (i.e., population level) versus calculating individual coefficients for each independent variable (i.e., individual level). We then related interindividual variability to individual characteristics (i.e., age, sex, reproductive status, body condition) in a multivariate analysis. The assumption of comparable behavior among individuals was verified only in 40% of the cases in our seasonal best models. Indeed, we found strong and opposite responses among sampled bears and individual coefficients were linked to individual characteristics. For some covariates, contrasted responses canceled each other out at the population level. In other cases, interindividual variability was concealed by the composition of our sample, with the majority of the bears (e.g., old individuals and bears in good physical condition) driving the population response (e.g., selection of young forest cuts). Our results stress the need to consider interindividual variability to avoid misinterpretation and uninformative results, especially for a flexible and opportunistic species. This study helps to identify some ecological drivers of interindividual variability in bear habitat selection patterns.

  17. An analysis of temperature effect in a finite journal bearing with spatial tilt and viscous dissipation

    NASA Technical Reports Server (NTRS)

    Braun, M. J.; Mullen, R. L.; Hendricks, R. C.

    1984-01-01

    The analysis presented herein deals with the evaluation of the pressure, velocity, and temperature profiles in a finite-length plane journal bearing. The geometry of the case under study consists of a spatially tilted shaft. The two-dimensional Reynolds equation accounts for the variation of the clearance gap h with x and z and is used to model the pressure field. The latter is solved for a variety of shaft tilt angles and then used to calculate the two-dimensional flow field. Finally, the flow field is used in the energy equation to solve for the film temperature profile, when the effect of viscous dissipation is taken into account.

  18. An analysis of temperature effect in a finite journal bearing with spatial tilt and viscous dissipation

    NASA Technical Reports Server (NTRS)

    Braun, M. J.; Mullen, R. L.; Hendricks, R. C.

    1984-01-01

    The analysis presented herein deals with the evaluation of the pressure, velocity, and temperature profiles in a finite-length plane journal bearing. The geometry of the case under study consists of a spatially tilted shaft. The two-dimensional Reynolds equation accounts for the variation of the clearance gap h with x and z and is used to model the pressure field. The latter is solved for a variety of shaft tilt angles and then used to calculate the two-dimensional flow field. Finally, the flow field is used in the energy equation to solve for the film temperature profile, when the effect of viscous dissipation is taken into account.

  19. Monitoring techniques for the X-29A aircraft's high-speed rotating power takeoff shaft

    NASA Technical Reports Server (NTRS)

    Voracek, David F.

    1990-01-01

    The experimental X-29A forward swept-wing aircraft has many unique and critical systems that require constant monitoring during ground or flight operation. One such system is the power takeoff shaft, which is the mechanical link between the engine and the aircraft-mounted accessory drive. The X-29A power takeoff shaft opertes in a range between 0 and 16,810 rpm, is longer than most jet engine power takeoff shafts, and is made of graphite epoxy material. Since the X-29A aircraft operates on a single engine, failure of the shaft during flight could lead to loss of the aircraft. The monitoring techniques and test methods used during power takeoff shaft ground and flight operations are discussed. Test data are presented in two case studies where monitoring and testing of the shaft dynamics proved instrumental in discovering and isolating X-29A power takeoff shaft problems. The first study concerns the installation of an unbalanced shaft. The effect of the unbalance on the shaft vibration data and the procedure used to correct the problem are discussed. The second study deals with the shaft exceeding the established vibration limits during flight. This case study found that the vibration of connected rotating machinery unbalances contributed to the excessive vibration level of the shaft. The procedures used to identify the contributions of other rotating machinery unbalances to the power takeoff shaft unbalance are discussed.

  20. Forging Long Shafts On Disks

    NASA Technical Reports Server (NTRS)

    Tilghman, Chris; Askey, William; Hopkins, Steven

    1989-01-01

    Isothermal-forging apparatus produces long shafts integral with disks. Equipment based on modification of conventional isothermal-forging equipment, required stroke cut by more than half. Enables forging of shafts as long as 48 in. (122 cm) on typical modified conventional forging press, otherwise limited to making shafts no longer than 18 in. (46cm). Removable punch, in which forged material cools after plastic deformation, essential novel feature of forging apparatus. Technology used to improve such products as components of gas turbines and turbopumps and of other shaft/disk parts for powerplants, drive trains, or static structures.

  1. Predicting shaft torque amplification

    SciTech Connect

    Achilles, R.A.

    1995-02-01

    Shaft Torque Amplification (STA) is the form of SSR characterized by the higher system-model complexity and computational requirements its simulation, normally in a time-domain environment, demands. A multi-modal approach drawing the turbogenerator torsional response to electrical torque impulses applied to the machine air-gap is introduced in this article as an alternative STA analysis frame. Peak torque results from the proposed algorithm are compared with similar ones obtained from EMTP runs. Loss-of-life calculations and a capacitor-reinsertion application as STA control means, are included.

  2. A case study on relation between roughness, lubrication and fatigue life of rolling bearings

    NASA Astrophysics Data System (ADS)

    Balan, M. R.; Tufescu, A.; Cretu, S. S.

    2016-08-01

    A spherical roller bearing under high radial loading, constant speed and imposed roughness for the contacting surfaces was chosen as case study. Different lubrication regimes were obtained by varying oil viscosity through the operating temperature. For bearings with especially machined contacting surfaces, λ-ratio is firstly determined and its value is used to estimate the particular value of the lubrication parameter κ. Using the λ-ratio approach the paper reveals the relationship between roughness amplitude and the modified rating life of rolling bearings. The roughness values corresponding to good manufacturing practice are possible to be determined for each particular case. Three groups of random Gaussian roughness were generated with the same values for the Ra parameter as used in the modified lives investigations. For medium and especially high radial loads, the contacts between rough surfaces develop, inside the shallow layer, von Mises equivalent stresses higher than the fatigue limit stress. For condition of lack of lubricant or starved lubrication, these findings explain the initiation of the rolling contact fatigue in the shallow layer, close to contacting surfaces.

  3. Vibration transmission through rolling element bearings. Part III: Geared rotor system studies

    NASA Astrophysics Data System (ADS)

    Lim, T. C.; Singh, R.

    1991-11-01

    This paper extends the proposed bearing matrix formulation of Parts I and II to analyze the overall dynamics of a geared rotor system which includes a spur gear pair, shafts, rolling element bearing, a prime mover and a load (attached to the geared rotor system through flexible torsional couplings), a rigid or flexible casing, and compliant or massive mounts. Linear time-invariant, discrete dynamic models of a generic geared rotor system with proportional viscous damping are developed, by using lumped parameter and dynamic finite element techniques, which are then used to predict the vibration transmissibility through bearings and mounts, casing vibration motion, and dynamic response of the internal rotating system. Each rotating shaft is modeled as an Euler beam in the lumped parameter model and as a Timoshenko beam in the dynamic finite element model, but the gyroscopic moment is not included. Eigensolution and forced harmonic response studies due to rotating mass unbalance or kinematic transmission error excitation for the following example cases are obtained by using the formulation, and the results are compared with those of simple models currently available in the literature and/or experiment: case I, a single-stage rotor system with flexibly mounted rigid casing consisting of two bearings as a special case of the geared rotor system; case II, a spur gear pair drive supported by four bearings installed in a flexibly mounted rigid casing; and case III, an experimental set-up consisting of a high-precision gear and pinion, and four identical rolling element bearings contained in a flexible casing mounted rigidly on a massive foundation. Analytical predictions show that the theory is indeed capable of predicting bearing and mount moment transmissibilities in addition to the force transmissibilities. Also, flexural vibrations of the casing plate are predicted well as the theory is in good agreement with measurements made on case III; such predictions are not

  4. Risk of hip, subtrochanteric, and femoral shaft fractures among mid and long term users of alendronate: nationwide cohort and nested case-control study

    PubMed Central

    Abrahamsen, Bo; Eiken, Pia; Eastell, Richard

    2016-01-01

    Objectives To determine the skeletal safety and efficacy of long term (≥10 years) alendronate use in patients with osteoporosis. Design Open register based cohort study containing two nested case control studies. Setting Nationwide study of population of Denmark. Participants 61 990 men and women aged 50-94 at the start of treatment, who had not previously taken alendronate, 1996-2007. Interventions Treatment with alendronate. Main outcome measures Incident fracture of the subtrochanteric femur or femoral shaft (ST/FS) or the hip. Non-fracture controls from the cohort were matched to fracture cases by sex, year of birth, and year of initiation of alendronate treatment. Conditional logistic regression models were fitted to calculate odds ratios with and without adjustment for comorbidity and comedications. Sensitivity analyses investigated subsequent treatment with other drugs for osteoporosis. Results 1428 participants sustained a ST/FS (incidence rate 3.4/1000 person years, 95% confidence interval 3.2 to 3.6), and 6784 sustained a hip fracture (16.2/1000 person years, 15.8 to 16.6). The risk of ST/FS was lower with high adherence to treatment with alendronate (medication possession ratio (MPR, a proxy for compliance) >80%) compared with poor adherence (MPR <50%; odds ratio 0.88, 0.77 to 0.99; P=0.05). Multivariable adjustment attenuated this association (adjusted odds ratio 0.88, 0.77 to 1.01; P=0.08). The risk was no higher in long term users (≥10 dose years; 0.70, 0.44 to 1.11; P=0.13) or in current compared with past users (0.91, 0.79 to 1.06; P=0.22). Similarly, MPR >80% was associated with a decreased risk of hip fracture (0.73, 0.68 to 0.78; P<0.001) as was longer term cumulative use for 5-10 dose years (0.74, 0.67 to 0.83; P<0.001) or ≥10 dose years (0.74, 0.56 to 0.97; P=0.03). Conclusions These findings support an acceptable balance between benefit and risk with treatment with alendronate in terms of fracture outcomes, even for over 10

  5. ["Teddy bear granuloma", a rare condition: a case report of a 3-year-old child].

    PubMed

    Batta, B; Robin, A; George, J-L; Angioi, K

    2012-02-01

    Conjunctival synthetic fiber granulomas, or "Teddy bear granulomas", are rare granulomatous responses to synthetic fabric fibers. We report the case of a 3-year-old boy with no prior infectious or traumatic history, brought in by his parents for an incidentally discovered conjunctival growth in his right eye. Slit lamp examination revealed a 10-mm growth in the inferior fornix surrounding a small greyish foreign body. Surgical excision and histopathology revealed granulomatous inflammatory cell response with foreign body giant cells surrounding exogenous material. This foreign material was birefringent in polarized light, very suggestive of synthetic fabric fibers, which permitted the diagnosis of Teddy bear granuloma. Synthetic fiber granulomas present in children as unilateral, more or less inflammatory growths in the inferior conjunctival fornix. Surgical excision with histopathology makes the diagnosis and effects the cure. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  6. On Geared Rotordynamic Systems with Oil Journal Bearings

    NASA Astrophysics Data System (ADS)

    THEODOSSIADES, S.; NATSIAVAS, S.

    2001-06-01

    This study investigates response and stability characteristics of rotordynamic systems interconnected with gear pairs and supported on oil journal bearings. The systems examined are driven by a motor providing a known torque, which is transferred to a load element through shafts and a gear box. Initially, the emphasis is placed on the gear-pair action, by assuming that the interconnecting shafts are rigid. This results in low order mechanical models with strongly non-linear characteristics, whose long-time dynamics are then effectively studied by applying appropriate numerical methodologies. In this way, useful information is obtained about the influence of the loading, the gear mesh and the journal parameters on the system dynamic behaviour, including periodic, quasi-periodic and chaotic response. Efforts are also directed towards predicting the onset of oil whirl instability and investigating its effects on the system dynamics. The focus is then shifted to more realistic models, including the flexibility of the interconnecting shafts. In this case, the order of the system is first reduced by applying a component mode synthesis method, which takes advantage of the fact that the non-linearities are located at the journal bearings and the gear mesh only. As a result, it is possible to study the dynamics of the reduced rotor-bearing model by employing the methodology that was developed for the gear-pair models.

  7. Unitary Shaft-Angle and Shaft-Speed Sensor Assemblies

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean C.; Howard, David E.; Smith, Dennis A.

    2006-01-01

    The figure depicts a unit that contains a rotary-position or a rotary-speed sensor, plus electronic circuitry necessary for its operation, all enclosed in a single housing with a shaft for coupling to an external rotary machine. This rotation sensor unit is complete: when its shaft is mechanically connected to that of the rotary machine and it is supplied with electric power, it generates an output signal directly indicative of the rotary position or speed, without need for additional processing by other circuitry. The incorporation of all of the necessary excitatory and readout circuitry into the housing (in contradistinction to using externally located excitatory and/or readout circuitry) in a compact arrangement is the major difference between this unit and prior rotation-sensor units. The sensor assembly inside the housing includes excitatory and readout integrated circuits mounted on a circular printed-circuit board. In a typical case in which the angle or speed transducer(s) utilize electromagnetic induction, the assembly also includes another circular printed-circuit board on which the transducer windings are mounted. A sheet of high-magnetic permeability metal ("mu metal") is placed between the winding board and the electronic-circuit board to prevent spurious coupling of excitatory signals from the transducer windings to the readout circuits. The housing and most of the other mechanical hardware can be common to a variety of different sensor designs. Hence, the unit can be configured to generate any of variety of outputs by changing the interior sensor assembly. For example, the sensor assembly could contain an analog tachometer circuit that generates an output proportional (in both magnitude and sign or in magnitude only) to the speed of rotation.

  8. Skew And Twist Resistant Hydrodynamic Rotary Shaft Seal

    DOEpatents

    Dietle, Lannie; Kalsi, Manmohan Singh

    2000-03-14

    A hydrodynamically lubricated squeeze packing type rotary shaft seal suitable for lubricant retention and environmental exclusion which incorporates one or more resilient protuberances which and cooperate with the gland walls to hold the seal straight in its installation groove in unpressurized and low pressure lubricant retention applications thereby preventing skew-induced wear caused by impingement of abrasive contaminants present in the environment, and which also serve as radial bearings to prevent tipping of the seal within its installation gland. Compared to prior art, this invention provides a dramatic reduction of seal and shaft wear in abrasive environments and provides a significant increase in seal life.

  9. Bearing tester data compilation, analysis, and reporting and bearing math modeling

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The Shaberth bearing analysis computer program was developed for the analysis of jet engine shaft/bearing systems operating above room temperature with normal hydrocarbon lubricants. It is also possible to use this tool to evaluate the shaft bearing systems operating in cryogenics. Effects such as fluid drag, radial temperature gradients, outer race misalignments and clearance changes were simulated and evaluated. In addition, the speed and preload effects on bearing radial stiffness was evaluated. The Shaberth program was also used to provide contact stresses from which contact geometry was calculated to support other analyses such as the determination of cryogenic fluid film thickness in the contacts and evaluation of surface and subsurface stresses necessary for bearing failure evaluation. This program was a vital tool for the thermal analysis of the bearing in that it provides the heat generation rates at the rolling element/race contacts for input into a thermal model of the bearing/shaft assembly.

  10. Calibration of shaft alignment instruments

    NASA Astrophysics Data System (ADS)

    Hemming, Bjorn

    1998-09-01

    Correct shaft alignment is vital for most rotating machines. Several shaft alignment instruments, ranging form dial indicator based to laser based, are commercially available. At VTT Manufacturing Technology a device for calibration of shaft alignment instruments was developed during 1997. A feature of the developed device is the similarity to the typical use of shaft alignment instruments i.e. the rotation of two shafts during the calibration. The benefit of the rotation is that all errors of the shaft alignment instrument, for example the deformations of the suspension bars, are included. However, the rotation increases significantly the uncertainty of calibration because of errors in the suspension of the shafts in the developed device for calibration of shaft alignment instruments. Without rotation the uncertainty of calibration is 0.001 mm for the parallel offset scale and 0,003 mm/m for the angular scale. With rotation the uncertainty of calibration is 0.002 mm for the scale and 0.004 mm/m for the angular scale.

  11. Magnetically leviated superconducting bearing

    DOEpatents

    Weinberger, Bernard R.; Lynds, Jr., Lahmer

    1993-01-01

    A magnetically levitated superconducting bearing includes a magnet (2) mounted on a shaft (12) that is rotatable around an axis of rotation and a Type II superconductor (6) supported on a stator (14) in proximity to the magnet (2). The superconductor (6) is positioned so that when it is cooled to its superconducting state in the presence of a magnetic field, it interacts with the magnet (2) to produce an attractive force that levitates the magnet (2) and supports a load on the shaft (12). The interaction between the superconductor (6) and magnet(2) also produces surface screening currents (8) that generate a repulsive force perpendicular to the load. The bearing also has means for maintaining the superconductor at a temperature below its critical temperature (16, 18). The bearing could also be constructed so the magnet (2) is supported on the stator (14) and the superconductor (6) is mounted on the shaft (12). The bearing can be operated by cooling the superconductor (6) to its superconducting state in the presence of a magnetic field.

  12. Thermal regime of ventilation shafts and its regulation

    SciTech Connect

    Petrov, N.N.; Timoshenko, N.I.

    1986-03-01

    This paper evaluates the regime of air flow through a ventilation shaft and the nondimensional heat-exchange criteria. It is shown that the air temperature in the shaft is affected more by the walls than by the reinforcement structure metal and that the heat released by internal combustion engines could be an alternative source for heating the air. High bypass aircraft turbojet engines decommissioned after their maximum surface life on planes could be used for this purpose. The study of the thermal regime in the shaft in the case of a sudden change of air temperature such as occurs during ventilation reversals has established the requirements for air heating equipment.

  13. Shaft seal assembly and method

    NASA Technical Reports Server (NTRS)

    Keba, John E. (Inventor)

    2007-01-01

    A pressure-actuated shaft seal assembly and associated method for controlling the flow of fluid adjacent a rotatable shaft are provided. The seal assembly includes one or more seal members that can be adjusted between open and closed positions, for example, according to the rotational speed of the shaft. For example, the seal member can be configured to be adjusted according to a radial pressure differential in a fluid that varies with the rotational speed of the shaft. In addition, in the closed position, each seal member can contact a rotatable member connected to the shaft to form a seal with the rotatable member and prevent fluid from flowing through the assembly. Thus, the seal can be closed at low speeds of operation and opened at high speeds of operation, thereby reducing the heat and wear in the seal assembly while maintaining a sufficient seal during all speeds of operation.

  14. A case of a fatal Himalayan black bear attack in the zoo.

    PubMed

    Mihailovic, Zoran; Savic, Slobodan; Damjanjuk, Irina; Stanojevic, Aleksandar; Milosevic, Miroslav

    2011-05-01

    We present a case of a 22-year-old male, who was found inside the cage of Himalayan black bears in the Belgrade Zoo. The victim attended the Belgrade Beer festival the previous night, drinking a lot of beer and acting aggressively. A medico-legal autopsy was performed at the Institute of Forensic Medicine in Belgrade. Autopsy findings showed numerous excoriations all over the body surrounded by bruises, as well as spindle-shaped, oval, and partly irregular wounds of variable size, large defects of skin and subcutaneous soft tissue, fractures of the thyroid and cricoid cartilage, and fracture of ribs. Postmortem toxicological analysis revealed the presence of ethanol in vitreous humor and urine and 11-nor Δ9 tetrahydrocannabinolic acid found in the urine. We discussed similar cases from the available literature in different regions of the world. In conclusion, we pointed out that the presented case does not follow the general pattern of Himalayan bear attacks. © 2011 American Academy of Forensic Sciences.

  15. Nonintrusive shaft speed sensor

    NASA Astrophysics Data System (ADS)

    Barkhoudarian, S.; Wyett, L.

    1985-04-01

    A computerized literature search on nonintrusive/noncontacting speed sensing technologies was performed, resulting in 550 abstracts and 42 articles. Fourteen techniques were identified and theoretically analyzed, resulting in the recommendation of the Microwave, Infrared, and Magnetic technologies for experimental evaluation. Test results with a novel magnetic approach, consisting of a permanent magnet placed on the rotating shaft and a pickup coil placed on the housing, indicated detection of a strong signal from 3.5 inches at the lowest required speed (600 rpm), through a 1.75-inch thick Inconel plate. Test results with microwave and infrared speed sensing approaches indicated transmission of sufficient microwave and infrared energy for detection even through heavily bubble-laden water (15 percent cavitation). Although all three techniques demonstrated feasibility, the magnetic sensor was recommended for preliminary design, which indicated no technical obstacles.

  16. One-stage emergency treatment of open grade IIIB tibial shaft fractures with bone loss.

    PubMed

    Tropet, Y; Garbuio, P; Obert, L; Jeunet, L; Elias, B

    2001-02-01

    The purpose of this study was to report the authors' experience with emergency reconstruction of severe tibial shaft fractures. Five male patients were admitted to the emergency room with a grade IIIB open tibial shaft fracture with bone loss (average age, 33 years; age range, 18-65 years). Injuries were the result of motorcycle accidents (N = 2), pedestrian accidents (N = 1), gunshot wound (N = 1), and paragliding fall (N = 1). Primary emergent one-stage management for all patients consisted of administration of antibiotics, debridement, stabilization by locked intramedullary nailing, bone grafting from the iliac crest, and coverage using free muscle flaps (four latissimus dorsi and one gracilis). The average follow-up was 21 months (range, 8 months-3.5 years). Partial weight bearing with no immobilization was started at 3 months, and full weight bearing began 5 months after trauma. No angular complications and no nonunions were observed. There was one case of superficial infection without osteitis. All fractures healed within 6 months in 4 patients and within 10 months in 1 patient. At the last follow-up examination, ankle and knee motion was normal and no pain was noted, except for 1 patient who had associated lesions (ankle motion reduced by 50%). Aggressive emergency management of severe open tibial fractures provides good results. It improves end results markedly, not only by reducing tissue loss from infection, but also reducing healing and rehabilitation times.

  17. System electrical parameters and their effects on bearing currents

    SciTech Connect

    Busse, D.; Erdman, J.; Kerkman, R.J.; Schlegel, D.; Skibinski, G.

    1997-03-01

    This paper examines ac motor shaft voltages and resulting bearing currents when operated under pulse width modulation (PWM) voltage source inverters. The paper reviews the electrical characteristics of bearings and motors that cause shaft voltages and bearing currents. A brief review of previous work is presented, including a system model for electrical analysis of bearing currents. Relying on the work of a companion paper, the propensity for electric discharge machining (EDM) is determined by a design equation that is a function of system components. Pertinent machine parameters and their formulas are presented and values calculated for machines from 5 to 1,000 hp. The effects of system elements on shaft voltages and bearing currents are evaluated experimentally and the results compared to theory. Finally, the paper will present quantitative results for one solution to the shaft voltage and bearing current problem.

  18. Dynamic Tester For Rotor Seals And Bearings

    NASA Technical Reports Server (NTRS)

    Von Pragenau, George L.

    1991-01-01

    Simplified apparatus measures performance under vibration. Measures some of dynamic parameters of rotor seals and bearings. Tests damping seals, damping bearings, conventional seals, and conventional bearings. Used with variety of pumped liquids, from water to liquid oxygen or hydrogen. Designed to test bearings and seals of turbopumps, tester rotates shaft at high speed while liquid flows much as it would in real turbopump. Also measures deflections of components.

  19. Dynamic Tester For Rotor Seals And Bearings

    NASA Technical Reports Server (NTRS)

    Von Pragenau, George L.

    1991-01-01

    Simplified apparatus measures performance under vibration. Measures some of dynamic parameters of rotor seals and bearings. Tests damping seals, damping bearings, conventional seals, and conventional bearings. Used with variety of pumped liquids, from water to liquid oxygen or hydrogen. Designed to test bearings and seals of turbopumps, tester rotates shaft at high speed while liquid flows much as it would in real turbopump. Also measures deflections of components.

  20. Dual rotating shaft seal apparatus

    DOEpatents

    Griggs, J.E.; Newman, H.J.

    1983-06-16

    The report is directed to apparatus suitable for transferring torque and rotary motion through a wall in a manner which is essentially gas impermeable. The apparatus can be used for pressurizing, agitating, and mixing fluids and features two ferrofluidic, i.e., ferrometic seals. Each seal is disposed on one of two supported shafts and each shaft is operably connected at one end to a gear mechanism and at its other end to an adjustable coupling means which is to be connected to a rotatable shaft extending through a wall through which torque and rotary motion are to be transferred.

  1. 30 CFR 56.19102 - Shaft guides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft guides. 56.19102 Section 56.19102 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Personnel Hoisting Shafts § 56.19102 Shaft guides. A means shall be provided to guide the movement of a shaft conveyance....

  2. 30 CFR 57.19102 - Shaft guides.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft guides. 57.19102 Section 57.19102 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Personnel Hoisting Shafts § 57.19102 Shaft guides. A means shall be provided to guide the movement of a shaft conveyance....

  3. Evaluation of shuttle turbopump bearings

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

    Because the high pressure turbopumps used on the space shuttle main engine (SSME) are high speed machines and rotor dynamics analysis of these units is very complicated, it was considered necessary to verify calculated turbomachinery shaft bearing loads by analysis of ball bearing load tracks. This report presents the methods used and the results of load track analysis on one set of bearings removed from a high pressure liquid oxygen turbopump which had been subjected to SSME static firing tests. This type of analysis was found useful in determining bearing operating conditions and for verifying rotor dynamics computer models.

  4. TIBIAL SHAFT FRACTURES.

    PubMed

    Kojima, Kodi Edson; Ferreira, Ramon Venzon

    2011-01-01

    The long-bone fractures occur most frequently in the tibial shaft. Adequate treatment of such fractures avoids consolidation failure, skewed consolidation and reoperation. To classify these fractures, the AO/OTA classification method is still used, but it is worthwhile getting to know the Ellis classification method, which also includes assessment of soft-tissue injuries. There is often an association with compartmental syndrome, and early diagnosis can be achieved through evaluating clinical parameters and constant clinical monitoring. Once the diagnosis has been made, fasciotomy should be performed. It is always difficult to assess consolidation, but the RUST method may help in this. Radiography is assessed in two projections, and points are scored for the presence of the fracture line and a visible bone callus. Today, the dogma of six hours for cleaning the exposed fracture is under discussion. It is considered that an early start to intravenous antibiotic therapy and the lesion severity are very important. The question of early or late closure of the lesion in an exposed fracture has gone through several phases: sometimes early closure has been indicated and sometimes late closure. Currently, whenever possible, early closure of the lesion is recommended, since this diminishes the risk of infection. Milling of the canal when the intramedullary nail is introduced is still a controversial subject. Despite strong personal positions in favor of milling, studies have shown that there may be some advantage in relation to closed fractures, but not in exposed fractures.

  5. TIBIAL SHAFT FRACTURES

    PubMed Central

    Kojima, Kodi Edson; Ferreira, Ramon Venzon

    2015-01-01

    The long-bone fractures occur most frequently in the tibial shaft. Adequate treatment of such fractures avoids consolidation failure, skewed consolidation and reoperation. To classify these fractures, the AO/OTA classification method is still used, but it is worthwhile getting to know the Ellis classification method, which also includes assessment of soft-tissue injuries. There is often an association with compartmental syndrome, and early diagnosis can be achieved through evaluating clinical parameters and constant clinical monitoring. Once the diagnosis has been made, fasciotomy should be performed. It is always difficult to assess consolidation, but the RUST method may help in this. Radiography is assessed in two projections, and points are scored for the presence of the fracture line and a visible bone callus. Today, the dogma of six hours for cleaning the exposed fracture is under discussion. It is considered that an early start to intravenous antibiotic therapy and the lesion severity are very important. The question of early or late closure of the lesion in an exposed fracture has gone through several phases: sometimes early closure has been indicated and sometimes late closure. Currently, whenever possible, early closure of the lesion is recommended, since this diminishes the risk of infection. Milling of the canal when the intramedullary nail is introduced is still a controversial subject. Despite strong personal positions in favor of milling, studies have shown that there may be some advantage in relation to closed fractures, but not in exposed fractures. PMID:27026999

  6. Dynamic Balancing Of Turbomachinery Shafts And Rotors

    NASA Technical Reports Server (NTRS)

    Verhoff, Vincent G.

    1993-01-01

    Method for dynamic balancing of turbomachinery shafts and rotors developed with view toward reducing time spent in balancing process. Improved method based on existing dynamic-balancing techniques and equipment, incorporating use of balancing arbor, which is mandrel duplicating mounting geometry and dynamic-balance properties of shaft balanced. Once shaft balanced, not necessary to disassemble machinery and/or shaft completely and rebalance shaft when replacing rotor on shaft. Instead, one balances replacement rotor on balancing arbor, then installs balanced rotor on shaft.

  7. Skew and twist resistant hydrodynamic rotary shaft seal

    DOEpatents

    Dietle, L.; Kalsi, M.S.

    1999-02-23

    A hydrodynamically lubricated squeeze packing type rotary shaft seal suitable for lubricant retention and environmental exclusion which incorporates one or more resilient protuberances which cooperate with the gland walls to hold the seal straight in its installation groove in unpressurized and low pressure lubricant retention applications thereby preventing skew-induced wear caused by impingement of abrasive contaminants present in the environment, and which also serve as radial bearings to prevent tipping of the seal within its installation gland. 14 figs.

  8. Skew and twist resistant hydrodynamic rotary shaft seal

    DOEpatents

    Dietle, Lannie; Kalsi, Manmohan Singh

    1999-01-01

    A hydrodynamically lubricated squeeze packing type rotary shaft seal suitable for lubricant retention and environmental exclusion which incorporates one or more resilient protuberances which and cooperate with the gland walls to hold the seal straight in its installation groove in unpressurized and low pressure lubricant retention applications thereby preventing skew-induced wear caused by impingement of abrasive contaminants present in the environment, and which also serve as radial bearings to prevent tipping of the seal within its installation gland.

  9. Application of Torsional Vibration Measurement to Shaft Crack Monitoring in Power Plants

    DTIC Science & Technology

    2001-04-05

    speed [8]. However, the shaft lateral vibration data exhibited none of the signs of whirl. In addition, the three closely spaced subsynchronous peaks were...these subsynchronous frequencies corresponds to the "rigid body" torsional mode on torsional springs corresponding to the bearing film stiffness in shear...5 -Run7 ..... Run 9 . .... R un ’OS- Rn J11 1.E-03 I.E-0, 0 2 3 4 5 Frequency (Hz) Figure 6: Subsynchronous torsional spectrum for hydro unit shaft

  10. Five-Axis, Three-Magnetic-Bearing Dynamic Spin Rig

    NASA Technical Reports Server (NTRS)

    Morrison, Carlos R.; Provenza, Andrew; Kurkov, Anatole; Mehmed, Oral; Johnson, Dexter; Montague, Gerald; Duffy, Kirsten; Jansen, Ralph

    2005-01-01

    The Five-Axis, Three-Magnetic-Bearing Dynamic Spin Rig is an apparatus for vibration testing of turbomachine blades in a vacuum at rotational speeds from 0 to 40,000 rpm. This rig includes (1) a vertically oriented shaft on which is mounted an assembly comprising a rotor holding the blades to be tested, (2) two actively controlled heteropolar radial magnetic bearings at opposite ends of the shaft, and (3) an actively controlled magnetic thrust bearing at the upper end of the shaft. This rig is a more capable successor to a prior apparatus, denoted the Dynamic Spin Rig (DSR), that included a vertically oriented shaft with a mechanical thrust bearing at the upper end and a single actively controlled heteropolar radial magnetic bearing at the lower end.

  11. Bearing currents and their relationship to PWM drives

    SciTech Connect

    Busse, D.; Erdman, J.; Kerkman, J.; Schlegel, D.; Skibinski, G.

    1997-03-01

    This paper examines ac motor shaft voltages and the resulting bearing currents when operated under pulse width modulation (PWM) voltage source inverters. The paper reviews the mechanical and electrical characteristics of the bearings and motor in relation to shaft voltages and bearing currents. A brief review of previous work is addressed, including the system model and experimental results. The theory of electric discharge machining (EDM) is presented, including component calculations of the system elements. The effect of system elements on shaft voltages and bearing currents are evaluated experimentally and the results compared to theory. A design calculation is proposed that provides the relative potential for EDM. Finally, the paper will present quantitative results on one solution to the shaft voltage and bearing current problem.

  12. Suprapatellar Nailing of Tibial Shaft Fractures in Total Knee Arthroplasty.

    PubMed

    Woyski, Dustin; Emerson, Jason

    2016-12-01

    Fractures of the tibial shaft in patients with ipsilateral total knee arthroplasty are rare but difficult to treat. Nonoperative treatment of these fractures with casting or bracing limits weight bearing for an extended period and can result in unacceptable malalignment. Operative fixation with plate and screws also limits early weight bearing and requires healing of soft tissue that is of poor quality. The authors present a method of internal fixation that uses a standard intramedullary tibial nail and suprapatellar instrumentation. This method can easily be performed, avoids the tibial baseplate, and does not require alteration of the instrumentation or intramedullary nail.

  13. Polar Bears in the Desert: A Case Study of the Operational and Strategic Impacts of the Iraq Surge on Tactical Units

    DTIC Science & Technology

    2016-06-10

    POLAR BEARS IN THE DESERT: A CASE STUDY OF THE OPERATIONAL AND STRATEGIC IMPACTS OF THE IRAQ SURGE ON TACTICAL UNITS A...2016 4. TITLE AND SUBTITLE Polar Bears in the Desert: A Case Study of the Operational and Strategic Impacts of the Iraq Surge on Tactical Units...Fawley, III Thesis Title: Polar Bears in the Desert: A Case Study of the Operational and Strategic Impacts of the Iraq Surge on Tactical Units

  14. Rolling-element bearings in China: From ancient times to the 20th century

    NASA Astrophysics Data System (ADS)

    Sun, Lie; Li, Ang

    2016-03-01

    The development of rolling-element bearings in China has spanned a long period. Based on several typical and important cases, the present article reconstructs the history of rolling-element bearings in China by dividing it into four stages according to the various characteristics of the bearings. The first stage represents the origin of rolling bearings in China, which remains controversial because of several suspected races and cages that were likely the components of bearings more than a millennium ago. At the second stage, a type of simple roller bearing was used for astronomical instruments not later than the 13th century based on clear philological and physical evidence. A similar bearing was also applied to an abridged armillary in the 17th century. Another type of spherical thrust bearings with rolling elements, which is a key component of a traditional Chinese windmill, could support a rotating shaft that moves rotationally and at an angle. At the third stage, the Chinese began studying and using the so-called Europeanstyle bearing since the 17th century. Moreover, over the last 100 years, the modern rolling bearing industry was gradually established in China, particularly because of the technology transfer from the Soviet Union in the 1950s. At the fourth stage, the Chinese government initiated the relatively rapid development of bearing technology. The government launched the "bearing movement" from the 1950s to the 1960s to establish the modern bearing industry and to promote rolling bearings as replacement for traditional sliding bearings. Furthermore, a number of large professional factories and institutions in China have continually introduced advanced technology and equipment. At present, these companies and institutions play a significant role in the international bearing industry.

  15. FORTRAN 4 computer program for calculating critical speeds of rotating shafts

    NASA Technical Reports Server (NTRS)

    Trivisonno, R. J.

    1973-01-01

    A FORTRAN 4 computer program, written for the IBM DCS 7094/7044 computer, that calculates the critical speeds of rotating shafts is described. The shaft may include bearings, couplings, extra masses (nonshaft mass), and disks for the gyroscopic effect. Shear deflection is also taken into account, and provision is made in the program for sections of the shaft that are tapered. The boundary conditions at the ends of the shaft can be fixed (deflection and slope equal to zero) or free (shear and moment equal to zero). The fixed end condition enables the program to calculate the natural frequencies of cantilever beams. Instead of using the lumped-parameter method, the program uses continuous integration of the differential equations of beam flexure across different shaft sections. The advantages of this method over the usual lumped-parameter method are less data preparation and better approximation of the distribution of the mass of the shaft. A main feature of the program is the nature of the output. The Calcomp plotter is used to produce a drawing of the shaft with superimposed deflection curves at the critical speeds, together with all pertinent information related to the shaft.

  16. Development of hybrid bearing system with thrust superconducting magnetic bearing and radial active electromagnetic bearing

    NASA Astrophysics Data System (ADS)

    Nicolsky, R.; Pereira, A. S.; de Andrade, R.; David, D. F. B.; Santisteban, J. A.; Stephan, R. M.; Ripper, A.; Gawalek, W.; Habisreuther, T.; Strasser, T.

    A superconducting/electromagnetic hybrid bearing system is currently under development and test. This system consists of a thrust superconducting magnetic bearing and a double radial active electromagnetic bearing/motor devices. The thrust bearing has been designed using NdFeB permanent magnets levitating on a set of superconducting monoliths of YBCO, prepared by top seeded melt texturing technique, which supports the weight of the rotor. The bearing/motor devices were conceived as 4-pole 2-phase induction machine using stator windings for delivering torque and radial positioning simultaneously. Using this superconducting axial bearing and the active bearings for the rotor radial positioning, a fully levitating vertical-shaft inductive machine has been tested. The tests were successful in reaching a controlled levitation up to 6,300 rpm.

  17. The effect of lower limb rehabilitation gymnastics on postoperative rehabilitation in elderly patients with femoral shaft fracture: A retrospective case-control study.

    PubMed

    Yang, Si-Dong; Ning, Sheng-Hua; Zhang, Li-Hong; Zhang, Ying-Ze; Ding, Wen-Yuan; Yang, Da-Long

    2016-08-01

    The purpose of this study was to explore the effect of lower limb rehabilitation gymnastics on postoperative rehabilitation in elderly patients with femoral shaft fracture after undergoing intramedullary nail fixation surgery.We collected medical records of elderly patients aged ≥ 60 years with femoral shaft fracture between 03/2010 and 03/2015 in Longyao County Hospital. Totally, 160 patients were identified and divided into the intervention group (n = 80) and the control group (n = 80). During the postoperative period, the intervention group received lower limb rehabilitation gymnastics treatment for 3 months, but the control group did not. All patients were routinely asked to return hospital for a check in the 1st postoperative week, as well as the 2nd week, the 1st month, and the 3rd month, after surgery. The clinical rehabilitation effect was evaluated by checking lower limb action ability, detecting the lower limb deep venous thrombosis (DVT), scoring muscle strength of quadriceps and visual analog scale (VAS) score, and performing satisfaction survey.At the 1st week and 2nd week after surgery, the clinical rehabilitation effect in the intervention group was better regarding lower limb action ability, lower limb DVT, muscle strength of quadriceps, VAS score, and patient satisfaction, as compared with the control group. However, there was no significant difference at the 1st month and the 3rd month after surgery when comparing the intervention group to the control group.In the early postoperative stage, lower limb rehabilitation gymnastics can effectively improve the recovery of lower limb function, beneficial to reducing postoperative complications such as lower limb DVT and muscle atrophy, and increasing patient satisfaction rate.

  18. The effects of PWM voltage source inverters on the mechanical performance of rolling bearings

    SciTech Connect

    Busse, D.F.; Erdman, J.M.; Kerkman, R.J.; Schlegel, D.W.; Skibinski, G.L.

    1997-03-01

    Modern power inverters provide the industrial control industry with significant advantages. The faster switching devices have increased drive performance, but with some recently discovered disadvantages. One disadvantage, rotor shaft voltage and resulting bearing current, has become an industry concern. The oil film in a bearing acts as a capacitor and provides a charging mechanism for rotor shaft voltage buildup. Electrical breakdown of the film can damage the bearing. This paper examines the mechanical and electrical characteristics of the bearing and converts them into models. The mechanical model for the bearing contact area establishes an allowable bearing current density, which is used to estimate the electrical life of a mechanical bearing. The electrical model for the bearing provides a significant advancement, aids bearing design, and the analysis of electrically induced bearing damage. Finally, the paper presents quantitative results for one solution to the shaft voltage and bearing current problem.

  19. Hydrodynamic and hydrostatic modelling of hydraulic journal bearings considering small displacement condition

    NASA Astrophysics Data System (ADS)

    Chen, Chi-Yin; Chuang, Jen-Chen; Tu, Jia-Ying

    2016-09-01

    This paper proposes modified coefficients for the dynamic model of hydraulic journal bearing system that integrates the hydrodynamic and hydrostatic properties. In recent years, design of hydraulic bearing for machine tool attracts worldwide attention, because hydraulic bearings are able to provide higher capacity and accuracy with lower friction, compared to conventional bearing systems. In order to achieve active control of the flow pressure and enhance the operation accuracy, the dynamic model of hydraulic bearings need to be developed. Modified coefficients of hydrostatic stiffness, hydrodynamic stiffness, and squeeze damping of the dynamic model are presented in this work, which are derived referring to small displacement analysis from literature. The proposed modified coefficients and model, which consider the pressure variations, relevant geometry size, and fluid properties of the journal bearings, are able to characterise the hydrodynamic and hydrostatic properties with better precision, thus offering the following pragmatic contribution: (1) on-line prediction of the eccentricity and the position of the shaft in the face of external force that results in vibration; (2) development of active control system to regulate the supply flow pressure and to minimize the eccentricity of the shaft. Theoretical derivation and simulation results with different vibration cases are discussed to verify the proposed techniques.

  20. Effects of Discrete Damping on the Dynamic Behaviour of Rotating Shaft through Extended Lagrangian Formulation

    NASA Astrophysics Data System (ADS)

    Rastogi, Vikas

    2016-09-01

    The main focus of the paper is touted as effects of discrete damping on the dynamic analysis of rotating shaft. The whole analysis is being carried out through extended Lagrangian formulation for a discrete - continuous system. The variation formulation for this system is possible, considering the continuous system as one-dimensional. The generalized formulation for one dimensional continuous rotary shaft with discrete external damper has been obtained through principle of variation. Using this extended formulation, the invariance of umbra-Lagrangian density through extended Noether's theorem is achieved. Rayleigh beam model is used to model the shaft. Amplitude equation of rotor is obtained theoretically and validated through simulation results. The simulation results reveal the important phenomena of limiting dynamics of the rotor shaft, which is due to an imbalance of material damping and stiffness of the rotor shaft. The regenerative energy in the rotor shaft, induced due to elasticity/stiffness of the rotor shaft, is dissipated partially through the in-span discrete damper and also through the dissipative coupling between drive and the rotor shaft. In such cases, the shaft speed will not increase with increase in excitation frequency of the rotor but the slip between the drive and the shaft increases due to loading of drive.

  1. Bacteriology of a bear bite wound to a human: case report.

    PubMed

    Kunimoto, Dennis; Rennie, Robert; Citron, Diane M; Goldstein, Ellie J C

    2004-07-01

    Human contact with bears has become more frequent, as has the resultant bear maulings and bite injuries. We report the bacteriology of a patient bitten by a grizzly bear (Ursus arctos) from the Rocky Mountains foothills area east of Banff National Park, Alberta, Canada. The patient received field care, including metronidazole and cefazolin. Subsequent deep-wound cultures grew Serratia fonticola, Serratia marcescens, Aeromonas hydrophila, Bacillus cereus, and Enterococcus durans but no anaerobes.

  2. Catastrophic stem taper wear in ceramic on polyethylene bearing couple: a case report.

    PubMed

    Kusaba, Atsushi; Katsui, Mariko; Hakuta, Naoyuki; Tsuchida, Masashi; Maeda, Akihiko; Kondo, Saiji

    2014-01-01

    A severe abrasion occurred at the stem taper 13 years after total hip arthroplasty. The bearing couple was 28 mm ceramic on polyethylene. The ceramic head had almost no damage, whereas the stem taper had severe damage. An ectopic bone probably contributed to the abrasion. The ectopic bone had grown to restrict the normal motion in the bearing couple and all stress and torque seemed to concentrate in the junction until the junction obtained mobility instead of the original bearing couple.

  3. Performance of computer-optimized tapered-roller bearings to 2.4 million DN

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Pinel, S. I.; Signer, H. R.

    1980-01-01

    The temperature distribution and bearing heat generation of 120.65 mm bore high-speed tapered roller bearings was determined at shaft speeds of 20,000 rpm under simultaneous thrust and radial loads. The temperatures and thermal outputs were computed as functions of shaft speed, loading lubricant flow rates, and lubricant inlet temperatures. Bearing temperatures and heat generation were considerably lower than in standard bearings; cup cooling was effective in lowering cup temperatures to levels of cone temperatures.

  4. [Case of trichinosis with lethal outcome due to consumption of brown bear meat in the Krasnoyarsk Territory].

    PubMed

    Rykov, V A; Kramarenko, G A

    1979-01-01

    One autopsy case of trichinellosis (in a man of 22) with extensive involvement of the locomotor apparatus (secondary infectious-allergic polymyositis) is presented. Group infection with trichinellosis occurred by eating of insufficiently treated meat of a brown bear which confirms the existence of a natural focus of trichinellosis in the Krasnoyarsky kray.

  5. A study of the transient performance of hydrostatic journal bearings. I - Test apparatus and facility

    NASA Astrophysics Data System (ADS)

    Scharrer, J. K.; Tellier, J.; Hibbs, R.

    1992-10-01

    A test apparatus was developed for studies of the transient performance of hydrostatic journal bearings operating in liquid nitrogen. The data obtained give the number of revolutions of the shaft contact before the liftoff and after touchdown as a function of bearing/shaft material combinations and operating conditions.

  6. Fixture For Testing Ball Bearings Under Radial Loads

    NASA Technical Reports Server (NTRS)

    Gibson, John

    1992-01-01

    Proposed fixture for mounting large ball bearings during tests facilitates application of variable, known radial loads, and prevent gross movement of bearing radial or axial directions. Load applied through Belleville spring washers to collar restrained by carrier ring. Load applied smoothly because collar and outer race of bearing flex in carrier ring. Inner race mounted on shaft rotated during application load.

  7. Applying low-intensity pulsed ultrasounds (LIPUS) to a zoledronate-associated atypical femoral shaft fracture without cessation of zoledronate therapy for 3 years follow up: a case report

    PubMed Central

    Arakawa, Shoutaro; Saito, Mitsuru; Kubota, Makoto; Suzuki, Hidehiko; Tsuchida, Shigeki; Hashimoto, Kurando; Marumo, Keishi

    2015-01-01

    Summary Reports are increasing regarding atypical femoral fractures (AFFs) caused by minor trauma in patients using bisphosphonates (BPs) for long periods. Patients with malignant skeletal metastases potentially are at greater risk for these AFFs, especially considering the high dose and the duration of treatment with BPs. We evaluated a case of atypical femoral shaft fracture treated with an intramedullary nail in a patient treated for five years with zoledronate who had breast cancer with metastases to bone. Although bone union was achieved without cessation of zoledronate therapy by applying low-intensity pulsed ultrasounds (LIPUS), the remodeling phase of the fracture healing process was delayed. For BPs-associated AFFs, LIPUS is an alternative to parathyroid hormone (PTH) analogs such as teriparatide that are contraindicated in patients with malignant skeletal metastases. LIPUS is an effective treatment for fracture healing and may avoid the necessity to discontinue BP therapy. PMID:26811711

  8. A "clearcut" case? Brown bear selection of coarse woody debris and carpenter ants on clearcuts.

    PubMed

    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%) in

  9. An exploratory shaft facility in SALT: Draft shaft study plan

    SciTech Connect

    Not Available

    1987-03-01

    This draft Shaft Study Plan describes a program of testing and monitoring in the Exploratory Shafts of a candidate high-level nuclear waste repository site in Deaf Smith County, Texas. The purpose of the programs to assist with site characterization in support of a determination of site suitability for development as a repository design and performance assessment evaluations. The program includes a variety of geological, geophysical, geomechanical, thermomechanical, and geohydrological testing and monitoring. The program is presented as a series of separate studies concerned with geological, geomechanical, and geohydrological site characterization, and with evaluating the mechanical and hydrological response of the site to construction of the shafts. The various studies, and associated test or monitoring methods are shown. The procedure used in developing the test program has been to initially identify the information necessary to satisfy (1) federal, state, and local requirements, and (2) repository program requirements. These information requirements have then been assessed to determine which requirements can be addressed wholly or in significant part by monitoring and testing from within the shafts. Test methods have been identified to address specific information requirements. 67 refs., 39 figs., 31 tabs.

  10. A miniature tilting pad gas lubricated bearing

    NASA Technical Reports Server (NTRS)

    Sixsmith, H.; Swift, W. L.

    1983-01-01

    This paper describes the design and development of a miniature tilting pad gas bearing developed for use in very small turbomachines. The bearings have been developed for cryogenic turboexpanders with shaft diameters down to about 0.3 cm and rotational speeds up to one million rpm. Cryogenic expansion turbines incorporating this type of bearing should be suitable for refrigeration rates down to about 10 w.

  11. Annular Pressure Seals and Hydrostatic Bearings

    DTIC Science & Technology

    2006-11-01

    minimal effect on the entrance pressure into the seal. Pressures vs shaft speed 0 10 20 30 40 50 60 70 0 1000 2000 3000 4000 5000 6000 Rotor Speed (RPM...speed 3600 rpm water seal, L/D=0.50, c=0.190 mm, D=152 mm L/D=0.50 Pressures vs shaft speed 0 10 20 30 40 50 60 70 0 1000 2000 3000 4000 5000 6000 Rotor...surface speed. Annular Pressure Seals and Hydrostatic Bearings 11 - 12 RTO-EN-AVT-143 Leakage vs shaft speed 0 2 4 6 8 10 12 14 16 18 0 1000 2000

  12. Optimization of pin bearing joint strength for segmented graphite/epoxy filament wound case in Space Shuttle

    NASA Technical Reports Server (NTRS)

    Munjal, A. K.; Wilks, R. K.

    1984-01-01

    An attempt is made to demonstrate the feasibility of a composite joint in a segmented, graphite/epoxy filament-wound composite case for the Space Shuttle's Solid Rocket Motors. The joint's required ultimate line load is of the of 82,000 lb/in. By optimizing composite layup, and the ratios of pin diameter/specimen thickness, edge distance/pin diameter, and specimen width/pin diameter, a pin bearing joint strength of 85 ksi was obtained. Double pin testing disclosed that the pin close to the composite joint carries a higher load than the outboard pin. Pin bearing strength is noted to vary with matrix resin system.

  13. The value of Weight-Bearing CT scan in the evaluation of subtalar distraction bone block arthrodesis: Case report.

    PubMed

    Welck, M J; Myerson, M S

    2015-12-01

    Subtalar distraction arthrodesis is performed in certain situations where there is loss of subtalar height, reduced talar declination and evidence of anterior tibiotalar impingement. Standard evaluation includes the assessment of the lateral talocalcaneal angle, calcaneal pitch, talocalcaneal height and talar declination angle on a weight bearing lateral radiograph. We present a case of erosive valgus subtalar osteoarthritis with subtalar collapse managed with a subtalar distraction arthrodesis. A weight bearing CT (WB-CT) scan was used in the assessment. The value of WB-CT for this indication is discussed, along with a discussion on surgical technique, complications and future directions. Copyright © 2015 European Foot and Ankle Society. All rights reserved.

  14. Vibration of rotating-shaft design spindles with flexible bases

    NASA Astrophysics Data System (ADS)

    Tseng, Chaw-Wu

    The purpose of this study is to demonstrate an accurate mathematical model predicting forced vibration of rotating-shaft HDD spindle motors with flexible stationary parts. The mathematical model consists of three parts: a rotating part, a stationary part, and bearings. The rotating part includes a flexible hub, a flexible shaft press-fit into the hub, and N elastic disks mounted on the hub. The stationary part can include motor bracket (stator), base casting, and top cover. The bearings under consideration can be ball bearings or hydrodynamic bearings (HDB). The rotating disks are modelled through the classical plate theory. The rotating part (except the disks) and the stationary part are modelled through finite element analyses (FEA). With mode shapes and natural frequencies obtained from FEA, the kinetic and potential energies of the rotating and stationary parts are formulated and discretized to compensate for the gyroscopic effects from rotation. Finally, use of Lagrange equation results in the equations of motion. To verify the mathematical model, frequency response functions are measured experimentally for an HDB spindle carrying two identical disks at motor and drive levels. Experimental measurements agree very well with theoretical predictions not only in resonance frequency but also in resonance amplitude.

  15. Solving bearing overheating problems

    SciTech Connect

    Jendzurski, T.

    1995-05-08

    Overheating is a major indicator, along with vibration and noise, of an underlying problem affecting a bearing or related components. Because normal operating temperatures vary widely from one application to another, no single temperature is a reliable sign of overheating in every situation. By observing an application when it is running smoothly, a technician can establish a benchmark temperature for a particular bearing arrangement. Wide deviations from this accepted norm generally indicate troublesome overheating. The list of possible causes of over-heating ranges from out-of-round housings and oversize shaft diameters to excessive lubrication and bearing preloading. These causes fall into two major categories: improper or faulty lubrication and mechanical problems, such as incorrect fits and tolerances. These are discussed along with solutions.

  16. Radial Shaft Reconstruction With an Intercalary Endoprosthesis Following Resection of Metastatic Tumor.

    PubMed

    Gibson, Peter D; Ippolito, Joseph A; Benevenia, Joseph

    2016-09-08

    Improvements in imaging and treatment of musculoskeletal tumors have increased the variety of options for reconstruction following joint-sparing diaphyseal resection. The purpose of this case series was to show that reconstruction of malignant tumors of the radial shaft with an intercalary prosthesis may be an option for patients with segmental bone loss. Three consecutive patients underwent wide resection of the radial diaphysis followed by reconstruction with a custom intercalary prosthesis. A custom intercalary prosthesis with lap joint design was used in all 3 cases. Mean follow-up was 18 months (range, 9-25 months). All patients were weight bearing as tolerated 1 week postoperatively. At the most recent follow-up, patients' mean elbow flexion and extension arc was 137° (range, 130°-140°). At the forearm, mean supination was 60° (range, 30°-90°) and mean pronation was 70° (range, 60°-90°). At the wrist, mean palmar flexion was 80° (range, 70°-90°) and mean dorsiflexion was 80° (range, 70°-90°). All patients reported minimal to no pain and no significant functional limitations. Mean Musculoskeletal Tumor Society score was 26/30 (87%). Reconstruction with an intercalary prosthesis is a viable option for patients with metastatic disease of the radial shaft. All patients had satisfactory results and early return to function; none required return to the operating room. Possible advantages of reconstruction with an intercalary prosthesis compared with reconstruction with a bone graft or polymethylmethacrylate osteosynthesis include early return to function and minimal weight-bearing restrictions postoperatively. [Orthopedics. 201x; xx(x):exx-exx.].

  17. Geotechnical instrumentation for repository shafts

    SciTech Connect

    Lentell, R.L.; Byrne, J.

    1993-09-01

    The US Congress passed the Nuclear Waste Policy Act in 1980, which required that three distinctly different geologic media be investigated as potential candidate sites for the permanent disposal of high-level nuclear waste. The three media that were selected for study were basalt (WA), salt (TX, LA, MS, UT), and tuff (NV). Preliminary Exploratory Shaft Facilities (ESF) designs were prepared for seven candidate salt sites, including bedded and domal salt environments. A bedded-salt site was selected in Deaf Smith County, TX for detailed site characterization studies and ESF Final Design. Although Congress terminated the Salt Repository Program in 1988, Final Design for the Deaf Smith ESF was completed, and much of the design rationale can be applied to subsequent deep repository shafts. This paper presents the rationale for the geotechnical instrumentation that was designed for construction and operational performance monitoring of the deep shafts of the in-situ test facility. The instrumentation design described herein can be used as a general framework in designing subsequent instrumentation programs for future high-level nuclear waste repository shafts.

  18. Femoral fracture repair using a locking plate technique in an adult captive polar bear (Ursus maritimus).

    PubMed

    Zimmerman, Dawn M; Dew, Terry; Douglass, Michael; Perez, Edward

    2010-02-01

    To report successful femoral fracture repair in a polar bear. Case report. Female polar bear (Ursus maritimus) 5 years and approximately 250 kg. A closed, complete, comminuted fracture of the distal midshaft femur was successfully reduced and stabilized using a compression plating technique with 2 specialized human femur plates offering axial, rotational, and bending support, and allowing the bone to share loads with the implant. Postoperative radiographs were obtained at 11.5 weeks, 11 months, and 24 months. Bone healing characterized by marked periosteal reaction was evident at 11 months with extensive remodeling evident at 24 months. No complications were noted. Distal mid shaft femoral fracture was reduced, stabilized, and healed in an adult polar bear with a locking plate technique using 2 plates. Previously, femoral fractures in polar bears were considered irreparable. Use of 2 plates applied with a locking plate technique can result in successful fracture repair despite large body weight and inability to restrict postoperative activity.

  19. Site study plan for exploratory shaft monitoring wells, Deaf Smith County Site, Texas: Preliminary Draft

    SciTech Connect

    Not Available

    1988-01-01

    As part of site characterization studies, two exploratory shafts will be constructed at the Deaf Smith County site, Texas. Twelve wells at five locations have been proposed to monitor potential impacts of shaft construction on water-bearing zones in the Ogallala Formation and the Dockum Group. In addition, tests have been proposed to determine the hydraulic properties of the water-bearing zones for use in design and construction of the shafts. Samples of the Blackwater Draw Formation, Ogallala Formation, and Dockum Group will be obtained during construction of these wells. Visual indentification, laboratory testing, and in situ testing will yield data necessary for Exploratory Shaft Facility design and construction. This activity provides the earliest data on the Blackwater Drew Formation, Ogallala Formation, and Dockum Group near the exploratory shaft locations. Drilling and hydrologic testing are scheduled prior to other subsurface activity at the Exploratory Shaft Facility to establish ground-water baseline conditions. The Technical Field Services Contractor is responsible for conducting the field program of drilling and testing. Samples and data will be handled and reported in accordance with established Salt Repository Project procedures. A quality assurance program will be utilized to assure that activities affecting quality are performed correctly and that the appropriate documentation is maintained. 45 refs., 11 figs., 4 tabs.

  20. Comparison of predicted and experimental thermal performance of angular-contact ball bearings

    NASA Technical Reports Server (NTRS)

    Parker, R. J.

    1984-01-01

    Predicted bearing heat generation and bearing temperature were verified by experimental data for ball bearings over a range of sizes, shaft speeds, and lubricant flow rates. The computer program Shaberth requires, as input, a factor which describes the air-oil mixture in the bearing cavity for calculation of the ball drag contribution to bearing heat generation. An equation for this lubricant percent volume in the bearing cavity was derived and appears to be valid over the range of test conditions including bearing bore sizes from 35 to 167 mm and shaft speeds from 1.0 to 3.0 million DN.

  1. Shaft Coupler With Friction and Spline Clutches

    NASA Technical Reports Server (NTRS)

    Thebert, Glenn W.

    1987-01-01

    Coupling, developed for rotor of lift/cruise aircraft, employs two clutches for smooth transmission of power from gas-turbine engine to rotor. Prior to ascent, coupling applies friction-type transition clutch that accelerates rotor shaft to speeds matching those of engine shaft. Once shafts synchronized, spline coupling engaged and friction clutch released to provide positive mechanical drive.

  2. 30 CFR 57.19133 - Shaft.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft. 57.19133 Section 57.19133 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Maintenance § 57.19133 Shaft. Shafts that have not been inspected within the past 7 days shall not be...

  3. Optoelectronic Shaft-Angle Encoder Tolerates Misalignments

    NASA Technical Reports Server (NTRS)

    Osborne, Eric P.

    1991-01-01

    Optoelectronic shaft-angle encoder measures angle of rotation of shaft with high precision while minimizing effects of eccentricity and other misalignments. Grooves on disk serve as reference marks to locate reading heads and measure increments of rotation of disk. Shaft-angle encoder, resembling optical compact-disk drive, includes two tracking heads illuminating grooves on disk and measures reflections from them.

  4. Metal-To-Composite Shaft Splice

    NASA Technical Reports Server (NTRS)

    Kish, Jules; Nguyen, Dean; Lauder, Tim

    1992-01-01

    Strong, lightweight shaft formed without awkward bolted flanges. Composite and metal portions of shaft joined by winding composite portion onto outer surface and into spiral groove of metal portion. Groove and composite material constitute structural bond. If opposing spiral grooves used, then two shafts locked together against torques in both directions.

  5. 30 CFR 56.19133 - Shaft.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft. 56.19133 Section 56.19133 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Maintenance § 56.19133 Shaft. Shafts that have not been inspected within the past 7 days shall not be...

  6. Noncontact Measurements Of Torques In Shafts

    NASA Technical Reports Server (NTRS)

    Schwartzbart, Aaron

    1991-01-01

    Additional information extracted from eddy-current proximeter. Positioned over rotating shaft, measures both displacement of and torsion in shaft. Torque applied to shaft calculable from output of proximeter. Possible to extract torsion information from existing tape-recorded proximeter data.

  7. 30 CFR 57.19106 - Shaft sets.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Shaft sets. 57.19106 Section 57.19106 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....19106 Shaft sets. Shaft sets shall be kept in good repair and clean of hazardous material....

  8. 30 CFR 56.19106 - Shaft sets.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Shaft sets. 56.19106 Section 56.19106 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Shaft sets. Shaft sets shall be kept in good repair and clean of hazardous material....

  9. 30 CFR 56.19106 - Shaft sets.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Shaft sets. 56.19106 Section 56.19106 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Shaft sets. Shaft sets shall be kept in good repair and clean of hazardous material....

  10. 30 CFR 57.19106 - Shaft sets.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Shaft sets. 57.19106 Section 57.19106 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....19106 Shaft sets. Shaft sets shall be kept in good repair and clean of hazardous material....

  11. 30 CFR 57.19106 - Shaft sets.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Shaft sets. 57.19106 Section 57.19106 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....19106 Shaft sets. Shaft sets shall be kept in good repair and clean of hazardous material....

  12. 30 CFR 57.19106 - Shaft sets.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Shaft sets. 57.19106 Section 57.19106 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....19106 Shaft sets. Shaft sets shall be kept in good repair and clean of hazardous material....

  13. 30 CFR 56.19106 - Shaft sets.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Shaft sets. 56.19106 Section 56.19106 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Shaft sets. Shaft sets shall be kept in good repair and clean of hazardous material....

  14. 30 CFR 56.19106 - Shaft sets.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Shaft sets. 56.19106 Section 56.19106 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Shaft sets. Shaft sets shall be kept in good repair and clean of hazardous material....

  15. 30 CFR 57.19106 - Shaft sets.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft sets. 57.19106 Section 57.19106 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....19106 Shaft sets. Shaft sets shall be kept in good repair and clean of hazardous material....

  16. 30 CFR 56.19106 - Shaft sets.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft sets. 56.19106 Section 56.19106 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Shaft sets. Shaft sets shall be kept in good repair and clean of hazardous material....

  17. 14 CFR 29.935 - Shafting joints.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Shafting joints. 29.935 Section 29.935... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must...

  18. 14 CFR 27.935 - Shafting joints.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Shafting joints. 27.935 Section 27.935... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have...

  19. 14 CFR 27.935 - Shafting joints.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Shafting joints. 27.935 Section 27.935... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have...

  20. 14 CFR 27.935 - Shafting joints.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Shafting joints. 27.935 Section 27.935... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have...

  1. 14 CFR 27.935 - Shafting joints.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Shafting joints. 27.935 Section 27.935... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have...

  2. 14 CFR 29.935 - Shafting joints.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Shafting joints. 29.935 Section 29.935... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must...

  3. 14 CFR 27.935 - Shafting joints.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Shafting joints. 27.935 Section 27.935... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must have...

  4. 14 CFR 29.935 - Shafting joints.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Shafting joints. 29.935 Section 29.935... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must...

  5. 14 CFR 29.935 - Shafting joints.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Shafting joints. 29.935 Section 29.935... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must...

  6. 14 CFR 29.935 - Shafting joints.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Shafting joints. 29.935 Section 29.935... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.935 Shafting joints. Each universal joint, slip joint, and other shafting joints whose lubrication is necessary for operation must...

  7. Influence of backup bearings and support structure dynamics on the behavior of rotors with active supports

    NASA Technical Reports Server (NTRS)

    Flowers, George T.

    1995-01-01

    Progress made in the current year is listed, and the following papers are included in the appendix: Steady-State Dynamic Behavior of an Auxiliary Bearing Supported Rotor System; Dynamic Behavior of a Magnetic Bearing Supported Jet Engine Rotor with Auxiliary Bearings; Dynamic Modelling and Response Characteristics of a Magnetic Bearing Rotor System with Auxiliary Bearings; and Synchronous Dynamics of a Coupled Shaft/Bearing/Housing System with Auxiliary Support from a Clearance Bearing: Analysis and Experiment.

  8. [Classification of femoral shaft fractures in hip arthroplasties].

    PubMed

    Baulot, E; Chabernaud, D; Grammont, P M

    1995-12-01

    Fractures of the femoral shaft around cemented hip prosthesis have become increasingly common and are difficult to manage. These fractures are often complex and may occur late after the insertion of a cemented prosthesis. They often occur in relation to cortical defects produced by cement and previous surgery. The main classifications already described can be divided into "anatomic" classifications (founded on the level of the fracture on the shaft: Parrish 1964, Ali Khan 1977, Van Elegem 1979) or into "prosthetic" classifications (founded on the level of the fracture with respect to the tip of the prosthesis: Johansson 1981, Bethea 1982, Cooke 1988). But these classifications give few guideliness to help the choice of the most appropriate form of treatment. The aim of treatment, which remains controversial, is to return to weight-bearing and mobility as promptly as possible so preventing the complications of immobilization which are frequent and serious in the often elderly population.

  9. Temperature field study of hot water circulation pump shaft system

    NASA Astrophysics Data System (ADS)

    Liu, Y. Y.; Kong, F. Y.; Daun, X. H.; Zhao, R. J.; Hu, Q. L.

    2016-05-01

    In the process of engineering application under the condition of hot water circulation pump, problems of stress concentration caused by the temperature rise may happen. In order to study the temperature field in bearing and electric motor chamber of the hot water circulation pump and optimize the structure, in present paper, the model of the shaft system is created through CREO. The model is analyzed by ANSYS workbench, in which the thermal boundary conditions are applied to calculate, which include the calorific values from the bearings, the thermal loss from electric motor and the temperature from the transporting medium. From the result, the finite element model can reflect the distribution of thermal field in hot water circulation pump. Further, the results show that the maximum temperature locates in the bearing chamber.The theoretical guidance for the electric motor heat dissipation design of the hot water circulation pump can be achieved.

  10. Laterally Translating Seal Carrier For A Drilling Mud Motor Sealed Bearing Assembly

    DOEpatents

    Dietle, Lannie

    1993-03-23

    A sealing and lubrication assembly for rotating shafts intended for operation in an abrasive environment and wherein the rotary shaft may have lateral translation or excursion during its rotation. A housing receives the rotary shaft in bearing supporting relation and defines a lubricant chamber about the shaft. A seal carrier is movably positioned about the rotary shaft and has non-rotatable articulating or laterally translating relation with the housing. A high pressure rotary shaft seal is supported by the seal carrier and maintains bearing and sealing engagement with the rotary shaft during its lateral translation or excursion. The seal carrier is hydraulic force balanced and thus is not subject to pressure induced loads that might otherwise interfere with its articulation or lateral translation.

  11. Direct shaft torque measurements in a transient turbine facility

    NASA Astrophysics Data System (ADS)

    Beard, Paul F.; Povey, Thomas

    2011-03-01

    This paper describes the development and implementation of a shaft torque measurement system for the Oxford Turbine Research Facility (formerly the Turbine Test Facility (TTF) at QinetiQ, Farnborough), or OTRF. As part of the recent EU TATEF II programme, the facility was upgraded to allow turbine efficiency measurements to be performed. A shaft torque measurement system was developed as part of this upgrade. The system is unique in that, to the authors' knowledge, it provided the first direct measurement of shaft torque in a transient turbine facility although the system has wider applicability to rotating test facilities in which power measurement is a requirement. The adopted approach removes the requirement to quantify bearing friction, which can be difficult to accurately calibrate under representative operating conditions. The OTRF is a short duration (approximately 0.4 s run time) isentropic light-piston facility capable of matching all of the non-dimensional parameters important for aerodynamic and heat studies, namely Mach number, Reynolds number, non-dimensional speed, stage pressure ratio and gas-to-wall temperature ratio. The single-stage MT1 turbine used for this study is a highly loaded unshrouded design, and as such is relevant to modern military, or future civil aero-engine design. Shaft torque was measured directly using a custom-built strain gauge-based torque measurement system in the rotating frame of reference. This paper describes the development of this measurement system. The system was calibrated, including the effects of temperature, to a traceable primary standard using a purpose-built facility. The bias and precision uncertainties of the measured torque were ±0.117% and ±0.183%, respectively. To accurately determine the shaft torque developed by a turbine in the OTRF, small corrections due to inertial torque (associated with changes in the rotational speed) and aerodynamic drag (windage) are required. The methods for performing these

  12. Random vibrations of a damped rotating shaft

    NASA Astrophysics Data System (ADS)

    Dimentberg, M. F.; Ryzhik, B.; Sperling, L.

    2005-01-01

    Response of a simple Jeffcott rotor to random excitation is considered with both external and internal damping taken into account. Mean square responses are predicted by the method of moments for the cases of transverse and angular (tilting) oscillations. Contrary to unbalance-induced response the random vibrations are shown to depend on the internal or "rotating" damping; in particular, their level increases with approaching threshold speed for dynamic instability. Procedure for estimating this threshold from on-line measurements of the shaft's random vibrations at a constant rotation speed is outlined based on the calculating coherence function of lateral displacements in two perpendicular directions for the case of transverse vibrations and that of tilting angles about two perpendicular axes for the case of tilting oscillations. Dependence of the mean square responses on the rotation speed can also be used for the stability margin evaluation.

  13. Shaft Diameter Measurement Using Structured Light Vision

    PubMed Central

    Liu, Siyuan; Tan, Qingchang; Zhang, Yachao

    2015-01-01

    A method for measuring shaft diameters is presented using structured light vision measurement. After calibrating a model of the structured light measurement, a virtual plane is established perpendicular to the measured shaft axis and the image of the light stripe on the shaft is projected to the virtual plane. On the virtual plane, the center of the measured shaft is determined by fitting the projected image under the geometrical constraints of the light stripe, and the shaft diameter is measured by the determined center and the projected image. Experiments evaluated the measuring accuracy of the method and the effects of some factors on the measurement are analyzed. PMID:26274963

  14. Shaft Diameter Measurement Using Structured Light Vision.

    PubMed

    Liu, Siyuan; Tan, Qingchang; Zhang, Yachao

    2015-08-12

    A method for measuring shaft diameters is presented using structured light vision measurement. After calibrating a model of the structured light measurement, a virtual plane is established perpendicular to the measured shaft axis and the image of the light stripe on the shaft is projected to the virtual plane. On the virtual plane, the center of the measured shaft is determined by fitting the projected image under the geometrical constraints of the light stripe, and the shaft diameter is measured by the determined center and the projected image. Experiments evaluated the measuring accuracy of the method and the effects of some factors on the measurement are analyzed.

  15. Performance of computer-optimized tapered-roller bearings to 2.4 million DN

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Pinel, S. I.; Signer, H. R.

    1980-01-01

    The performance of 120.65 mm bore high speed design tapered roller bearings was investigated at shaft speeds to 20,000 rpm under combined thrust and radial load. The test bearing design was computer optimized for high speed operation. Temperature distribution and bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rates, and lubricant inlet temperature. The roller bearing operated successfully at shaft speeds up to 20,000 rpm under heavy thrust and radial loads. Cup cooling was effective in decreasing the high cup temperatures to levels equal to the cone temperature.

  16. Evolution of cyclic plasticity during rolling contact fatigue of a case-hardened bearing steel

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Abir

    A combined experimental and numerical methodology is developed for the investigation of progressive evolution of subsurface plasticity during prolonged rolling contact fatigue (RCF) loading of a M50 NiL case hardened steel. Three balls-on-rod RCF tests have been performed on a M50 NiL steel rod a using silicon nitride balls over several hundred million cycles at 5.5 GPa contact stress level. A systematic investigation of the evolution of surface contact area between the ball and the rod reveals that the contact pressure evolves continuously during several hundred million cycles of RCF due to substantial surface and subsurface plasticity. Various stages of plastic deformation has been identified based on the nature of the evolution of contact patch during the first phase of study. In the second phase of research, systematic investigation on the nucleation and the growth of the plastically deformed subsurface regions in a case hardened M-50 NiL steel rod has been done. The microhardness measurements within the RCF affected subsurface regions revealed existence of hardened and softened regions, which grow in size and severity with stress cycles. A mechanistic explanation behind the formation of the hardened and softened regions inside the plastic zone and its growth in size and severity has been proposed in the second phase of the work. In the final phase of the study, we propose a generalized methodology to determine the cyclic constitutive response of the various case layers of M-50 NiL steel. A 3-dimenstional finite element (FE) model of the ball-on-rod test was simulated in ABAQUS and the obtained von Mises stresses were used along with measured microhardness values and Neuber's rule to obtain the cyclic strain amplitudes at various points inside the RCF affected region. The S-N diagram of M-50 NiL steel is constructed and the fatigue limit of the material under RCF loading is determined after considering the effect of compressive mean stress. It has been shown

  17. Active magnetic bearings used as exciters for rolling element bearing outer race defect diagnosis.

    PubMed

    Xu, Yuanping; Di, Long; Zhou, Jin; Jin, Chaowu; Guo, Qintao

    2016-03-01

    The active health monitoring of rotordynamic systems in the presence of bearing outer race defect is considered in this paper. The shaft is assumed to be supported by conventional mechanical bearings and an active magnetic bearing (AMB) is used in the mid of the shaft location as an exciter to apply electromagnetic force to the system. We investigate a nonlinear bearing-pedestal system model with the outer race defect under the electromagnetic force. The nonlinear differential equations are integrated using the fourth-order Runge-Kutta algorithm. The simulation and experimental results show that the characteristic signal of outer race incipient defect is significantly amplified under the electromagnetic force through the AMBs, which is helpful to improve the diagnosis accuracy of rolling element bearing׳s incipient outer race defect.

  18. Rotor/bearing system dynamic stiffness measurements

    NASA Technical Reports Server (NTRS)

    Muszynska, A.

    1985-01-01

    Sweep perturbation testing as used in Modal Analysis when applied to a rotating machine has to take into consideration the machine dynamic state of equilibrium at its operational rotative speed. This stands in contrasts to a static equilibrium of nonrotating structures. The rotational energy has a significant influence on rotor dynamic characteristics. The best perturbing input for rotating machines is a forward or reverse rotating, circular force applied directly to the shaft. Determination of Dynamic Stiffness Characteristics of the rotor bearing system by nonsynchronous perturbation of a symmetric rotating shaft supported in one relatively rigid and one oil lubricated bearing.

  19. Nonlinear dynamic modeling for a diesel engine propeller shafting used in large marines

    NASA Astrophysics Data System (ADS)

    Zhang, Qinglei; Duan, Jianguo; Zhang, Suohuai; Fu, Yumin

    2014-09-01

    Longitudinal vibration, torsional vibration and their coupled vibration are the main vibration modes of the crankshaft-sliding bearing system. However, these vibrations of the propeller-crankshaft-sliding bearing system generated by the fluid exciting force on the propeller are much more complex. Currently, the torsional and longitudinal vibrations have been studied separately while the research on their coupled vibration is few, and the influence of the propeller structure to dynamic characteristics of a crankshaft has not been studied yet. In order to describe the dynamic properties of a crankshaft accurately, a nonlinear dynamic model is proposed taking the effect of torsional-longitudinal coupling and the variable inertia of propeller, connecting rod and piston into account. Numerical simulation cases are carried out to calculate the response data of the system in time and frequency domains under the working speed and over-speed, respectively. Results of vibration analysis of the propeller and crankshaft system coupled in torsional and longitudinal direction indicate that the system dynamic behaviors are relatively complicated especially in the components of the frequency response. For example, the 4 times of an exciting frequency acting on the propeller by fluid appears at 130 r/min, while not yield at 105 r/min. While the possible abnormal vibration at over-speed just needs to be vigilant. So when designing the propeller shafting used in marine diesel engines, strength calculation and vibration analysis based only on linear model may cause great errors and the proposed research provides some references to design diesel engine propeller shafting used in large marines.

  20. Nonintrusive shaft speed sensor

    NASA Technical Reports Server (NTRS)

    Barkhoudarian, S.; Wyett, L.; Maram, J.

    1985-01-01

    Reusable rocket engines such as the Space Shuttle Main Engines (SSME), the Orbital Transfer Vehicles (OTV), etc., have throttling capabilities that require real-time, closed-loop control systems of engine propellant flows, combustion temperatures and pressures, and turbopump rotary speeds. In the case of the SSME, there are four turbopumps that require real-time measurement and control of their rotary speeds. Variable-reluctance magnetic speed sensors were designed, fabricated, and tested for all four turbopumps, resulting in the successful implementation and operation of three of these speed sensors during each of the 12 Shuttle flights.

  1. Hermetic seal for a shaft

    NASA Technical Reports Server (NTRS)

    Lombardi, F. (Inventor)

    1982-01-01

    An hermetic seal for a linear rod having a portion thereof projected axially through a port defined in a wall for a pressure chamber and supported thereby for omni-directional motion is described. The seal is characterized by a resilient, impervious, cylindrical body having a first section concentrically related to the shaft and integrally affixed thereto comprising a linear ordered array of annular flutes. A second section integrally is affixed to the wall of the chamber and concentrically related to the port comprising a second linear ordered array of annular flutes. A third section is interposed between the first and second sections and integrally affixed in coaxial alignment therewith comprising an annular ordered array of linear flutes concentrically related to the shaft, whereby axial, angular, and pivotal motion of the rod is accommodated.

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

    SciTech Connect

    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

  3. [Reconstruction intramedullary nailing for treatment of ispsilateral femoral neck and shaft fractures].

    PubMed

    Wang, Hao; Li, Lian-hua; Liu, Zhi; Zhang, Jian-zheng; Guo, Yong-zhi

    2015-09-01

    To evaluate the curative effect and surigical skills of reconstruction intramedullary nailing in the treatment of ipsilateral femoral neck and shaft fractures. From January 2007 to January 2013, 13 patients with ipsilateral femoral neck and shaft fractures were treated by reconstruction intramedullary nailing including 11 males and 2 females with an average age of 38.9 yeas old ranging from 25 to 53 years old. For femoral neck fractures,10 cases were basilar neck fracture, 3 were transcervical fractures and according to Garden classification,10 were type II, 2 were type III and 1 was type IV. For feormal shaft fracture, 5 were type I, 4 were type II, 3 were type III and 1 was type IV according to Winquist classification. The location of all 13 feormal shaft fractures were all in the uper 3/4 of the feormal shaft. Complications and postoperative function were recorded and evaluated. Eleven patients were followed up for 23.45 months (12 to 36 months). Time from injury to operation was 5.9 days in average. Malunion of femoral neck fracture happened in 1 patient, nonunion of femoral shaft fracture happened in 2 patients. NO femoral head osteonecrosis, infection and malunion of femoral shaft fracture happened. According to Friedman-Wyman classification, 8 cases get good result, 2 get faii and 1 get poor. Reconstruction intramedullary nailing is a good choice for the ipsilateral femoral neck and shaft fractures with the advantages of less soft-tissue trauma and complications.

  4. Time-frequency vibration analysis for the detection of motor damages caused by bearing currents

    NASA Astrophysics Data System (ADS)

    Prudhom, Aurelien; Antonino-Daviu, Jose; Razik, Hubert; Climente-Alarcon, Vicente

    2017-02-01

    Motor failure due to bearing currents is an issue that has drawn an increasing industrial interest over recent years. Bearing currents usually appear in motors operated by variable frequency drives (VFD); these drives may lead to common voltage modes which cause currents induced in the motor shaft that are discharged through the bearings. The presence of these currents may lead to the motor bearing failure only few months after system startup. Vibration monitoring is one of the most common ways for detecting bearing damages caused by circulating currents; the evaluation of the amplitudes of well-known characteristic components in the vibration Fourier spectrum that are associated with race, ball or cage defects enables to evaluate the bearing condition and, hence, to identify an eventual damage due to bearing currents. However, the inherent constraints of the Fourier transform may complicate the detection of the progressive bearing degradation; for instance, in some cases, other frequency components may mask or be confused with bearing defect-related while, in other cases, the analysis may not be suitable due to the eventual non-stationary nature of the captured vibration signals. Moreover, the fact that this analysis implies to lose the time-dimension limits the amount of information obtained from this technique. This work proposes the use of time-frequency (T-F) transforms to analyse vibration data in motors affected by bearing currents. The experimental results obtained in real machines show that the vibration analysis via T-F tools may provide significant advantages for the detection of bearing current damages; among other, these techniques enable to visualise the progressive degradation of the bearing while providing an effective discrimination versus other components that are not related with the fault. Moreover, their application is valid regardless of the operation regime of the machine. Both factors confirm the robustness and reliability of these tools

  5. Polar bears in the Beaufort Sea: A 30-year mark-recapture case history

    USGS Publications Warehouse

    Amstrup, Steven C.; McDonald, T.L.; Stirling, I.

    2001-01-01

    Knowledge of population size and trend is necessary to manage anthropogenic risks to polar bears (Ursus maritimus). Despite capturing over 1,025 females between 1967 and 1998, previously calculated estimates of the size of the southern Beaufort Sea (SBS) population have been unreliable. We improved estimates of numbers of polar bears by modeling heterogeneity in capture probability with covariates. Important covariates referred to the year of the study, age of the bear, capture effort, and geographic location. Our choice of best approximating model was based on the inverse relationship between variance in parameter estimates and likelihood of the fit and suggested a growth from ≈ 500 to over 1,000 females during this study. The mean coefficient of variation on estimates for the last decade of the study was 0.16—the smallest yet derived. A similar model selection approach is recommended for other projects where a best model is not identified by likelihood criteria alone.

  6. Comparison of vibration amplitude supression vs. dynamic bearing load suppression in active vibration control of rotating machinery

    NASA Astrophysics Data System (ADS)

    Clark, William W.; Kim, J. H.; Marangoni, Roy D.

    1993-04-01

    This paper presents two optimal control methods for attenuating steady-state vibrations in rotating machinery. One method minimizes shaft displacements while the other minimizes dynamic bearing reaction forces. The two methods are applied to a model of a typical rotating machinery system, and their results are compared. It is found that displacement minimization can increase bearing loads, while bearing load minimization, on the other hand, decreases bearing loads without significant change in shaft displacements.

  7. Runner seal air injection eliminates shaft resonance problem

    SciTech Connect

    Barbour, J.; March, P.

    1997-02-01

    A method for solving a turbine generator shaft vibration problem is outlined in the article. The vibration problem occurred in an Ontario Hydro unit replacement turbine generator when it was taken above the 80% wicket gate position for the first time. Runout at the turbine bearing doubled in frequency and increased in amplitude by a factor of six. Steps taken to diagnose and correct the problem are detailed in the article. After unsuccessfully attempting conventional solutions, the utility solved the vibration problem by injecting compressed air into the runner band upper seal.

  8. Low Leakage Turbine Shaft Seals for Advanced Combined Cycle Systems.

    DTIC Science & Technology

    1984-11-01

    Study of Shaft Face Seal With Self-Acting Lift Augmentation", N71- 11579, Nov. 1970 29p. Povinelli , V.P. and McKibbin, A. H., "Development of...34, N73-24086, May 1973, 28p. Povinelli , V. P. and McKibbin, A. H., "Development of Mainshaft Seals for Advanced Air Breathing Propulsion Systems... Povinelli , V. P., "Current Seal Designs and Future Requirements for Turbine Engine Seals and Bearings", Journal of Aircraft, Vol. 12, No. 4, April 1975

  9. Stepping-Motion Motor-Control Subsystem For Testing Bearings

    NASA Technical Reports Server (NTRS)

    Powers, Charles E.

    1992-01-01

    Control subsystem closed-loop angular-position-control system causing motor and bearing under test to undergo any of variety of continuous or stepping motions. Also used to test bearing-and-motor assemblies, motors, angular-position sensors including rotating shafts, and like. Monitoring subsystem gathers data used to evaluate performance of bearing or other article under test. Monitoring subsystem described in article, "Monitoring Subsystem For Testing Bearings" (GSC-13432).

  10. Rolling Element Bearing Stiffness Matrix Determination (Presentation)

    SciTech Connect

    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.

  11. Dynamic force response of spherical hydrostatic journal bearings for cryogenic applications

    NASA Astrophysics Data System (ADS)

    Andres, Luis San

    1994-07-01

    Hydrostatic journal bearings are ideal elements to replace roller bearings as rotor support elements in cryogenic turbomachinery. These bearings will be used for primary space-power applications due to their long lifetime, low friction and wear, large load capacity, and direct stiffness and damping force coefficients. The performance characteristics of turbulent flow, orifice compensated, spherical hydrostatic journal bearings are presented. These bearing allow tolerance for shaft misalignment without force degradation and are able to support axial loads, thus providing a design configuration which could be used efficiently on high-performance turbomachinery. Bulk-flow mass and momentum equations for the motion of a variable properties liquid on the thin film bearing lands are solved numerically. Predictions of load capacity and force coefficients for a six recess, spherical hydrostatic bearing in a liquid oxygen environment are presented. Fluid film axial forces and dynamic coefficients of a magnitude about 20 percent of the radial load capacity are calculated for the case analyzed. Fluid inertia effects, advective and centrifugal, are found to greatly affect the static and dynamic force characteristics of the bearing studied.

  12. Analysis on volume invariability of metal circular shaft in torsion deformation

    NASA Astrophysics Data System (ADS)

    Yang, Li-Hong; Zou, Guang-Ping; He, Yun-Zeng; Wang, Hui

    2009-12-01

    Volume invariability of metal circular shaft in the case of small strain torsion deformation and large strain torsion deformation was, respectively, discussed experimentally and theoretically in this study. In accordance with the elastoplastic theory, it was given that the shear stress did not cause the change of volume in the large strain range. By utilizing torsion experiment with the solid shaft of low carbon steel, it was proved that metal can meet the conditions of the volume invariability in torsion deformation while the cumulative damage was not very serious. Volumetric deformation was analyzed in torsion of circular shaft in the perspective of micromechanics. Finally, Swift effect of solid circular shaft and tubular shaft of brass material were interpreted by using the formulae of elastoplastic critic load obtained from double-limb bar model test presented by Shanley.

  13. Analysis on volume invariability of metal circular shaft in torsion deformation

    NASA Astrophysics Data System (ADS)

    Yang, Li-Hong; Zou, Guang-Ping; He, Yun-Zeng; Wang, Hui

    2010-03-01

    Volume invariability of metal circular shaft in the case of small strain torsion deformation and large strain torsion deformation was, respectively, discussed experimentally and theoretically in this study. In accordance with the elastoplastic theory, it was given that the shear stress did not cause the change of volume in the large strain range. By utilizing torsion experiment with the solid shaft of low carbon steel, it was proved that metal can meet the conditions of the volume invariability in torsion deformation while the cumulative damage was not very serious. Volumetric deformation was analyzed in torsion of circular shaft in the perspective of micromechanics. Finally, Swift effect of solid circular shaft and tubular shaft of brass material were interpreted by using the formulae of elastoplastic critic load obtained from double-limb bar model test presented by Shanley.

  14. Load-bearing masonry system adoption and performance: A case study of construction company in a developing country

    NASA Astrophysics Data System (ADS)

    Ramli, Nor Azlinda; Abdullah, Che Sobry; Nawi, Mohd Nasrun Mohd; Bahaudin, Ahmad Yusni

    2016-08-01

    This study addresses the factors that influence the adoption of load-bearing masonry (LBM) system. A case study of the load-bearing masonry (LBM) system adoption is conducted through an interview to explore the situation of the technology adoption in a construction company. The finding indicates the factors influence the adoption of LBM system for the construction company are: organizational resources, usefulness, less maintenance, reduce construction time and cost. From the findings, these factors consistent with previous literature. Furthermore, the performance of the company was measured by looking into the financial and non-financial aspects. The LBM system brings good performance as it increased the profits of the company, a good quality of product and attracts more demand from customers. Thus, these factors should be considered for the other companies that are interested in implementing the LBM system in their projects.

  15. A do-it-yourself membrane-activated auditory feedback device for weight bearing and gait training: a case report.

    PubMed

    Batavia, M; Gianutsos, J G; Vaccaro, A; Gold, J T

    2001-04-01

    An augmented auditory feedback device comprised of a thin membrane switch mini-buzzer, and battery is described as a modification of a previously described feedback device. The membrane switch can be customized for the patient and is designed to fit inside a patient's shoe without altering the heel height. Its appeal lies in its simplicity of construction, low cost, and ease of implementation during a patient's training for weight bearing and gait. An ever-present source of information, it provides performance-relevant cues to both patient and clinician about the occurrence, duration, and location of a force component of motor performance. The report includes suggested applications of the device, instructions to construct it, and a case report in which the device was used to improve weight bearing and gait in a cognitively healthy person with spina bifida.

  16. Gross Motor Outcomes After Dynamic Weight-Bearing in 2 Children With Trunk Hypotonia: A Case Series.

    PubMed

    Ardolino, Elizabeth; Flores, Megan; Manella, Kathleen

    2017-10-01

    Children with trunk hypotonia may have limited ability to maintain an upright weight-bearing position, resulting in decreased postural control and a delay in achieving gross motor milestones. The purpose of this case series is to report the effect of a home-based dynamic standing program on postural control and gross motor activity in 2 children with trunk hypotonia. Child 1 (aged 24 months, Gross Motor Function Classification Scale Level IV) and Child 2 (aged 21 months, Gross Motor Function Classification Scale Level V) participated in a standing program using the Upsee harness at home 3 days per week for 12 weeks. Both children improved their gross motor function, and Child 1 demonstrated improved trunk control in sitting. The use of the Upsee harness was an effective intervention for these children with trunk hypotonia to achieve weight-bearing and improve gross motor abilities.

  17. Cracked shaft detection on large vertical nuclear reactor coolant pump

    NASA Technical Reports Server (NTRS)

    Jenkins, L. S.

    1985-01-01

    Due to difficulty and radiation exposure associated with examination of the internals of large commercial nuclear reactor coolant pumps, it is necessary to be able to diagnose the cause of an excessive vibration problem quickly without resorting to extensive trial and error efforts. Consequently, it is necessary to make maximum use of all available data to develop a consistent theory which locates the problem area in the machine. This type of approach was taken at Three Mile Island, Unit #1, in February 1984 to identify and locate the cause of a continuously climbing vibration level of the pump shaft. The data gathered necessitated some in-depth knowledge of the pump internals to provide proper interpretation and avoid misleading conclusions. Therefore, the raw data included more than just the vibration characteristics. Pertinent details of the data gathered is shown and is necessary and sufficient to show that the cause of the observed vibration problem could logically only be a cracked pump shaft in the shaft overhang below the pump bearing.

  18. Development of a high speed parallel hybrid boost bearing

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

    The analysis, design, and testing of the hybrid boost bearing are discussed. The hybrid boost bearing consists of a fluid film bearing coupled in parallel with a rolling element bearing. This coupling arrangement makes use of the inherent advantages of both the fluid film and rolling element bearing and at the same time minimizes their disadvantages and limitations. The analytical optimization studies that lead to the final fluid film bearing design are reported. The bearing consisted of a centrifugally-pressurized planar fluid film thrust bearing with oil feed through the shaft center. An analysis of the test ball bearing is also presented. The experimental determination of the hybrid bearing characteristics obtained on the basis of individual bearing component tests and a combined hybrid bearing assembly is discussed and compared to the analytically determined performance characteristics.

  19. Shaft mount for data coupler system

    NASA Technical Reports Server (NTRS)

    Elliott, James R., Jr. (Inventor); Lord, Mark T. (Inventor)

    1993-01-01

    A device for mounting a data transmission apparatus to a rotating, tapered, and instrumented shaft is provided. This device permits attachment without interfering with shaft rotation or the accuracy of data output, and prevents both radial and axial slippage of the data transmission apparatus. The mounting device consists of a sleeve assembly which is attached to the shaft by means of clamps that are situated at some distance removed from the instrumented area of the shaft. The data transmission device is secured to the sleeve such that the entire assembly rotates with the shaft. Shim adjustments between sleeve sections assure that a minimum compressive load is transferred to the instrumented area of the shaft and a rubber lining is affixed to a large portion of the interior surface of the sleeve to absorb vibration.

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

    NASA Technical Reports Server (NTRS)

    Dimofte, Florin

    1995-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Dimofte, Florin

    1995-01-01

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

  2. Bearing tester data compilation, analysis and reporting and bearing math modeling, volume 1

    NASA Technical Reports Server (NTRS)

    Marshall, D. D.; Montgomery, E. E.; New, L. S.; Stone, M. A.; Tiller, B. K.

    1984-01-01

    Thermal and mechanical models of high speed angular contact ball bearings operating in LOX and LN2 were developed and verified with limited test data in an effort to further understand the parameters that determine or effect the SSME turbopump bearing operational characteristics and service life. The SHABERTH bearing analysis program which was adapted to evaluate shaft bearing systems in cryogenics is not capable of accommodating varying thermal properties and two phase flow. A bearing model with this capability was developed using the SINDA thermal analyzer. Iteration between the SHABERTH and the SINDA models enable the establishment of preliminary bounds for stable operation in LN2. These limits were established in terms of fluid flow, fluid inlet temperature, and axial load for a shaft speed of 30,000 RPM.

  3. Space Shuttle Orbital Maneuvering Subsystem (OMS) Engine Propellant Leakage Ball-Valve Shaft Seals

    NASA Technical Reports Server (NTRS)

    Lueders, Kathy; Buntain, Nick; Fries, Joseph (Technical Monitor)

    1999-01-01

    Evidence of propellant leakage across ball-valve shaft seals has been noted during the disassembly of five flight engines and one test engine at the NASA Lyndon B. Johnson Space Center, White Sands Test Facility. Based on data collected during the disassembly of these five engines, the consequences of propellant leakage across the ball-valve shaft seals can be divided into four primary areas of concern: Damage to the ball-valve pinion shafts, damage to sleeved bearings inside the ball-valve and actuator assemblies, degradation of the synthetic rubber o-rings used in the actuator assemblies, and corrosion and degradation to the interior of the actuator assemblies. The exact time at which leakage across the ball-valve shaft seals occurs has not been determined, however, the leakage most likely occurs during engine firings when, depending on the specification used, ball-valve cavity pressures range as high as 453 to 550 psia. This potential pressure range for the ball-valve cavities greatly exceeds the acceptance leakage test pressure of 332 psia. Since redesign and replacement of the ball-valve shaft seals is unlikely, the near term solution to prevent damage that occurs from shaft-seal leakage is to implement a routine overhaul and maintenance program for engines in the fleet. Recommended repair, verification, and possible preventative maintenance measures are discussed in the paper.

  4. Space Shuttle Orbital Maneuvering Subsystem (OMS) Engine Propellant Leakage Ball-Valve Shaft Seals

    NASA Technical Reports Server (NTRS)

    Lueders, Kathy; Buntain, Nick; Fries, Joseph (Technical Monitor)

    1999-01-01

    Evidence of propellant leakage across ball-valve shaft seals has been noted during the disassembly of five flight engines and one test engine at the NASA Lyndon B. Johnson Space Center, White Sands Test Facility. Based on data collected during the disassembly of these five engines, the consequences of propellant leakage across the ball-valve shaft seals can be divided into four primary areas of concern: Damage to the ball-valve pinion shafts, damage to sleeved bearings inside the ball-valve and actuator assemblies, degradation of the synthetic rubber o-rings used in the actuator assemblies, and corrosion and degradation to the interior of the actuator assemblies. The exact time at which leakage across the ball-valve shaft seals occurs has not been determined, however, the leakage most likely occurs during engine firings when, depending on the specification used, ball-valve cavity pressures range as high as 453 to 550 psia. This potential pressure range for the ball-valve cavities greatly exceeds the acceptance leakage test pressure of 332 psia. Since redesign and replacement of the ball-valve shaft seals is unlikely, the near term solution to prevent damage that occurs from shaft-seal leakage is to implement a routine overhaul and maintenance program for engines in the fleet. Recommended repair, verification, and possible preventative maintenance measures are discussed in the paper.

  5. 30 CFR 57.19100 - Shaft landing gates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft landing gates. 57.19100 Section 57.19100... Shafts § 57.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates so... unloading shaft conveyances....

  6. 30 CFR 57.19111 - Shaft-sinking ladders.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft-sinking ladders. 57.19111 Section 57... Hoisting Shafts § 57.19111 Shaft-sinking ladders. Substantial fixed ladders shall be provided from the collar to as near the shaft bottom as practical during shaft-sinking operations, or an escape...

  7. 30 CFR 56.19111 - Shaft-sinking ladders.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft-sinking ladders. 56.19111 Section 56... Shafts § 56.19111 Shaft-sinking ladders. Substantial fixed ladders shall be provided from the collar to as near the shaft bottom as practical during shaft-sinking operations, or an escape hoist powered...

  8. Computer-aided selection of materials for cryogenic turbopump bearings

    NASA Technical Reports Server (NTRS)

    Maurer, R. E.; Pallini, R. A.

    1985-01-01

    The life requirement for the angular contact ball bearings in the Space Shuttle Main Engine (SSME) high-pressure-oxygen turbopump (HPOTP) is 7.5 hours. In actual operation, significantly shorter service life has been experienced. The objective of this current program is to identify bearing materials and/or materials processing techniques offering significant potential for extending HPOTP bearing performance life. A thermomechanical analysis of the HPOTP shaft/bearing system was performed with the SHABERTH (SHaft-BEaring-THermal) computer program. Bearing fatigue life, ball-race contact stress, heat generation rate, bulk ring temperatures, and circumferential stress in the inner rings were quantified as functions of radial load, thrust load, and ball-race contact friction. The analysis results were used to formulate criteria that are being used for the selection of special materials for future turbopump bearings.

  9. Treatment of pediatric femoral shaft fractures by stainless steel and titanium elastic nail system: A randomized comparative trial.

    PubMed

    Gyaneshwar, Tank; Nitesh, Rustagi; Sagar, Tomar; Pranav, Kothiyal; Rustagi, Nitesh

    2016-08-01

    Literature suggests that the lower modulus of elasticity of titanium makes it ideal for use in children compared with stainless steel. Better fracture stability was observed in association with titanium nails on torsional and axial compression testing. However, stainless steel nails are stiffer than titanium counterparts, which may provide a rigid construct when fixing paediatric femoral shaft fractures. Complications have been observed more frequently by various researchers when titanium nails are used for fracture fixation in patients with increasing age or weight. The concept of this study was to compare the functional outcome after internal fixation with titanium elastic nail system and stainless steel elastic nail system in paediatric femoral shaft fractures. The study was conducted on 34 patients admitted in the department of orthopaedics, LLRM Medical College & SVBP Hospital, Meerut, India from January 2013 to August 2014. We included patients aged 5-12 years with fracture of the femoral shaft, excluding compound fractures, pathological fractures and other lower limb fractures. Patients were treated by titanium (n=17) or stainless steel (n=17) elastic nail system and followed up for one year. The clinical parameters like range of motion at hip and knee joints, time to full weight bearing on the operated limb and radiological parameters like time to union were compared between two groups. A special note was made of intra- and post-operative complications. Functional outcomes were analysed according to Flynn criteria. Based on the Flynn criteria, 59% of patients had excellent results, 41% had satisfactory results, and no one showed poor results. There was no clinically significant difference between the two groups with respect to time to union and full weight bearing. But the incidence of puncture of the opposite cortex while inserting the nail and trying to advance it through the diaphysis during operation is greatly different. Only one such case was observed

  10. Monitoring Bearing Vibrations For Signs Of Damage

    NASA Technical Reports Server (NTRS)

    Martinez, Carol L.

    1991-01-01

    Real-time spectral analysis of vibrations being developed for use in monitoring conditions of critical bearings in rotating machinery. Underlying concept simple and fairly well established: appearance and growth of vibrations at frequencies associated with rotations of various parts of bearing system indicate wear, damage, and imperfections of manufacture. Frequencies include fundamental and harmonics of frequency of rotation of ball cage, frequency of passage of balls, and frequency of rotation of shaft.

  11. Monitoring Bearing Vibrations For Signs Of Damage

    NASA Technical Reports Server (NTRS)

    Martinez, Carol L.

    1991-01-01

    Real-time spectral analysis of vibrations being developed for use in monitoring conditions of critical bearings in rotating machinery. Underlying concept simple and fairly well established: appearance and growth of vibrations at frequencies associated with rotations of various parts of bearing system indicate wear, damage, and imperfections of manufacture. Frequencies include fundamental and harmonics of frequency of rotation of ball cage, frequency of passage of balls, and frequency of rotation of shaft.

  12. Lubrication of high-speed, large bore tapered-roller bearings

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Signer, H. R.

    1978-01-01

    The performance of 120.65-mm bore tapered-roller bearings was investigated at shaft speeds up to 15,000 rpm. Temperature distribution and bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rate, and lubricant inlet temperature. Lubricant was supplied either by jets or by a combination of holes through the cone directly to the cone-rib contact and jets at the roller small-end side. Cone-rib lubrication significantly improved high-speed tapered-roller bearing performance, yielding lower cone-face temperatures and lower power loss and allowing lower lubricant flow rates for a given speed condition. Bearing temperatures increased with increased shaft speed and decreased with increased lubricant flow rate. Bearing power loss increased with increased shaft speed and increased lubricant flow rate.

  13. Lubrication of high-speed, large bore tapered-roller bearings

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Signer, H. R.

    1977-01-01

    The performance of 120.65-mm- (4.75-in.-) bore tapered-roller bearings was investigated at shaft speeds up to 15,000 rpm (18,000 DN). Temperature distribution and bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rate, and lubricant inlet temperature. Lubricant was supplied either by jets or by a combination of holes through the cone directly to the cone-rib contact and jets at the roller small-end side. Cone-rib lubrication significantly improved high-speed tapered-roller bearing performance, yielding lower cone-face temperatures and lower power loss and allowing lower lubricant flow rates for a given speed condition. Bearing temperatures increased with increased shaft speed and decreased with increased lubricant flow rate. Bearing power loss increased with increased shaft speed and increased lubricant flow rate.

  14. Bearings and gears for advanced turbine engines and transmissions

    NASA Technical Reports Server (NTRS)

    Parker, R. J.

    1975-01-01

    The improved technology is discussed of engine main-shaft ball bearings, and spur gears in power transmission drive trains. Much of the technology can be applied to other ball and roller bearings, and to other spur and bevel gears throughout the engine, drive train, and accessory systems.

  15. Silicon nitride used as a rolling-element bearing material

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

    Rolling-element fatigue tests were conducted with hot-pressed silicon nitride to determine its ability to withstand concentrated contacts in rolling-element bearings. If hot-pressed silicon nitride is used for both balls and races, attention must be paid to fitting both shaft and bearing housing.

  16. [Fractures of the tibial shaft].

    PubMed

    Märdian, S; Schwabe, P; Schaser, K-D

    2015-02-01

    The tibia shaft is the most often fractured long bone of human beings. Among others traffic accidents (37.5 %), falls (17.8 %), sport accidents (30.9 %) and assaults (4.5 %) are typical mechanisms. A brief clinical examination including the correct classification of the fracture pattern and even more important the degree of the soft tissue damage are the most crucial factors for the following therapeutic cascade. This follows a defined algorithm based on the degree of soft tissue damage. As biplanar X-ray diagnostics are obligatory, CT scans are subject to complex fracture patterns and accompanying intraarticular pathologies.The treatment of tibial shaft fractures is the preserve of operative stabilization, which should be done primarily depending on the degree of the soft tissue injury. Here intramedullary methods - especially intramedullary nailing - are the golden standard.The most serious complication of these fractures is the development of a compartment syndrome. This requires rapid diagnosis and an adequate surgical management in order to avoid extensive muscle necrosis with ischaemic contractures and irreversible neurovascular deficits. Apart from postoperative infections, which are the predominant complication especially in open injuries, non union provide typical and late complications which are partly difficult to treat. These should, depending on their type, follow a dedicated treatment algorithm.

  17. Algorithm for the management of femoral shaft fractures in children.

    PubMed

    Sanzarello, I; Calamoneri, E; D'Andrea, L; Rosa, M A

    2014-06-01

    Pediatric closed femoral shaft fractures are commonly related to a good prognosis. There is no consensus on treatment. We aimed to evaluate the treatment, features, radiological findings and management strategies, creating an algorithm of treatment. Fifty-two simple femoral shaft fractures in children were retrospectively evaluated for age and gender distribution, side of the fracture, etiology of injuries, limb length discrepancy, range of knee and hip motion and parents satisfaction with a mean clinical and radiographic follow-up of 3 years and 6 months. Twenty-eight patients were treated with reduction and early hip spica cast while 24 patients were treated with external fixation (EF). Nearly 58 % of the cases were caused by traffic accidents and were predominantly male (61.5 %). Most of the fractures were of the middle femoral shaft (57.6 %). Muscle strength was normal (MRC scale) in all patients with no pain (NIPS and PRS scale). Knee and Hip range of motion were similar in both types of treatment. Patients treated with EF had shorter limb length discrepancy compared with SC. There were no reports of re-fracture. We found a higher familiar satisfaction in patients treated with EF. An algorithm for the management of femoral shaft fractures in the pediatric population is proposed. Results on the study population gave raise to a satisfactory clinical and radiological results.

  18. Adaptive Spindle Balancing Using Magnetically Levitated Bearings

    SciTech Connect

    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.

  19. Shaft mines can get power without armor

    SciTech Connect

    Brezovec, D.

    1984-02-01

    A Pennsylvania coal operator has been able to install neoprene jacketed mine power feeder (MPF) cable in an airshaft without the use of expensive armored power cables. Armored cables traditionally have been favored in applications where the cable is dropped vertically because their galvanized metal shielding protects the cable as it is dragged across rough ground and stretched by its own weight as it is lowered into the hole. But armored cable poses some problems. It is as much as $20 per foot more expensive than MPF cable. Also, sinking armored cables is particularly difficult when space is limited because the cable must be laid out on the ground before it is lowered into the hole. The technique that allowed Pennsylvania Mines Corp. to install two 750-ft-long, 15-kv cables at is 400,000-tpy Tunnelton mine, near New Alexandria, Pa., was devised by J.H. Service Co.'s Indianola, Pa., branch office. The method involves feeding MPF cable from a spool on a truck equipped with special braking devices, over a steel drum that acts as a sheave, directly into a mine shaft or borehole. Robert C. Kadyk, a sales manager with J.H. Service, says that while this is not the first time standard MPF cable has been used in a borehole or shaft, the cables are not usually used in these cases because there were no dependable methods for holding the cable steady as it was lowered into the hole to keep it from abrading against the sides of the borehole or shaft. Also, dragging MPF cable through the woods invariably damages it. With its cable sinking method, J.H. Service vulcanizes stainless steel kellems grips into the cable about every 100 ft. The interval varies with the weight and diameter of the cable, depth of the hole, and length of the kellems grip. One twisted steel messenger wire is attached to each kellems grip to displace the weight of the cable as it takes its trip to the mine floor.

  20. Wave Journal Bearing. Part 1: Analysis

    NASA Technical Reports Server (NTRS)

    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.

  1. Optimal speed sharing characteristics of a series-hybrid bearing.

    NASA Technical Reports Server (NTRS)

    Nypan, L. J.; Scibbe, H. W.; Hamrock, B. J.

    1972-01-01

    A series-hybrid bearing assembly consisting of a conical hydrostatic fluid-film bearing and a ball bearing is described. Computer studies are used to predict friction torque and life characteristics of a 150-mm ball bearing. A conical hydrostatic fluid-film bearing is designed for minimum friction and maximum speed reduction of the ball-bearing component of the series-hybrid bearing. At a thrust load of 4000 lb and speeds corresponding to DN (bearing bore in millimeters times shaft speed in rpm) values of 3 and 4 million, ball-bearing speed may be reduced to 30%. This speed reduction corresponds to ball-bearing fatigue life improvement factors of 3.4 at 3 million DN and 5.9 at 4 million DN. An oil flow rate at 18.2 lb/min is required to maintain a fluid-film thickness of 0.001 in. in the hydrostatic bearing.

  2. Optimal speed sharing characteristics of a series-hybrid bearing

    NASA Technical Reports Server (NTRS)

    Nypan, L. J.; Scibbe, H. W.; Hamrock, B. J.

    1972-01-01

    A series-hybrid bearing assembly consisting of a conical hydrostatic fluid-film bearing and a ball bearing is described. Computer studies are used to predict friction torque and life characteristics of a 150-millimeter ball bearing. A conical hydrostatic fluid-film bearing is designed for minimum friction and maximum speed reduction of the ball-bearing component of the series-hydrid bearing. At a thrust load of 4000 pounds and speeds corresponding to DN (bearing bore in millimeters times shaft speed in rpm) values of 3 and 4 million, ball-bearing speed may be reduced by 30 percent. This speed reduction corresponds to ball-bearing fatigue life improvement factors of 3.4 at 3 million DN and 5.9 at 4 million DN. An oil flow rate of 18.2 pounds per minute is required to maintain a fluid-film thickness of 0.001 inch in the hydrostatic bearing.

  3. Modelling the deflection of rowing oar shafts.

    PubMed

    Laschowski, Brock; Hopkins, Cameron C; de Bruyn, John R; Nolte, Volker

    2017-03-01

    The deflection of rowing oar shafts subjected to a static load was investigated. Two sets of sculling oars of different design stiffness were tested at three different lengths from 2.66 to 2.70 m. Loads up to 201 N were applied to the blade end of the oar shafts, and deflections were measured at six positions along the length of the shafts. The experimental results were compared with theoretical predictions obtained by modelling the oar shafts as homogenous end-loaded cantilever beams. The results show that the oar shafts are not uniform, in contradiction to the assumed model, but rather are most compliant near the sleeves and up to 80% stiffer towards the blades. The effect of oar shaft stiffness and length on the deflection angle at the blade end of the oar shaft was at most 1.18 ± 0.01°. The measured variation of stiffness along the shaft has implications for boat propulsion and rowing performance.

  4. Spiral groove seal. [for rotating shaft

    NASA Technical Reports Server (NTRS)

    Ludwig, L. P.; Strom, T. N. (Inventor)

    1974-01-01

    Mating flat surfaces inhibit leakage of a fluid around a stationary shaft. A spiral groove produces a pumping action toward the fluid when the shaft rotates. This prevents leakage while a generated hydraulic lifting force separates the mating surfaces to minimize wear. Provision is made for placing these spiral grooves in communication with the fluid to accelerate the generation of the hydraulic lifting force.

  5. Dynamic force response of spherical hydrostatic journal bearing for cryogenic applications

    NASA Technical Reports Server (NTRS)

    Sanandres, Luis

    1994-01-01

    Hydrostatic Journal Bearings (HJB's) are reliable and resilient fluid film rotor support elements ideal to replace roller bearings in cryogenic turbomachinery. HJB' will be used for primary space-power applications due to their long lifetime, low friction and wear, large load capacity, large direct stiffness, and damping force coefficients. An analysis for the performance characteristics of turbulent flow, orifice compensated, spherical hydrostatic journal bearings (HJB's) is presented. Spherical bearings allow tolerance for shaft misalignment without force performance degradation and have also the ability to support axial loads. The spherical HJB combines these advantages to provide a bearing design which could be used efficiently on high performance turbomachinery. The motion of a barotropic liquid on the thin film bearing lands is described by bulk-flow mass and momentum equations. These equations are solved numerically using an efficient CFD method. Numerical predictions of load capacity and force coefficients for a 6 recess, spherical HJB in a LO2 environment are presented. Fluid film axial forces and force coefficients of a magnitude about 20% of the radial load capacity are predicted for the case analyzed. Fluid inertia effects, advective and centrifugal, are found to affect greatly the static and dynamic force performance of the bearing studied.

  6. Lubrication of optimized-design tapered-roller bearings to 2.4 million DN

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Pinel, S. I.; Signer, Hans R.

    1980-01-01

    The performance of 120.65 mm (4.75 in.) bore high speed design, tapered roller bearings was investigated at shaft speeds to 20,000 rpm (2.4 million DN) under combined thrust and radial load. The test bearing design was computer optimized for high speed operation. Temperature distribution bearing heat generation were determined as a function of shaft speed, radial and thrust loads, lubricant flow rates, and lubricant inlet temperature. The high speed design, tapered roller bearing operated successfully at shaft speeds up to 20,000 rpm under heavy thrust and radial loads. Bearing temperatures and heat generation with the high speed design bearing were significantly less than those of a modified standard bearing tested previously. Cup cooling was effective in decreasing the high cup temperatures to levels equal to the cone temperature.

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

    NASA Technical Reports Server (NTRS)

    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

  8. [Elbow dislocation with ipsilateral proximal radial shaft fracture and radial head dislocation].

    PubMed

    Köhn, N; Mendel, T; Ullrich, B W

    2015-11-01

    Elbow dislocation with ipsilateral proximal radial shaft fracture and dislocated radial head is a rarely described injury. In this article we present the case of a 23-year-old man with this injury. After the initial diagnostics, the radial shaft fracture was osteosynthetically fixed, whereby the anatomical positions of all parts of the elbow joint were correctly aligned and the medial collateral ligament was reconstructed. After 4.5 months the radial shaft fracture was healed with nearly complete functional recovery of the upper extremity. Thus, a good outcome can be expected when all aspects of bony and ligamentous injuries are accurately addressed.

  9. Online shaft encoder geometry compensation for arbitrary shaft speed profiles using Bayesian regression

    NASA Astrophysics Data System (ADS)

    Diamond, D. H.; Heyns, P. S.; Oberholster, A. J.

    2016-12-01

    The measurement of instantaneous angular speed is being increasingly investigated for its use in a wide range of condition monitoring and prognostic applications. Central to many measurement techniques are incremental shaft encoders recording the arrival times of shaft angular increments. The conventional approach to processing these signals assumes that the angular increments are equidistant. This assumption is generally incorrect when working with toothed wheels and especially zebra tape encoders and has been shown to introduce errors in the estimated shaft speed. There are some proposed methods in the literature that aim to compensate for this geometric irregularity. Some of the methods require the shaft speed to be perfectly constant for calibration, something rarely achieved in practice. Other methods assume the shaft speed to be nearly constant with minor deviations. Therefore existing methods cannot calibrate the entire shaft encoder geometry for arbitrary shaft speeds. The present article presents a method to calculate the shaft encoder geometry for arbitrary shaft speed profiles. The method uses Bayesian linear regression to calculate the encoder increment distances. The method is derived and then tested against simulated and laboratory experiments. The results indicate that the proposed method is capable of accurately determining the shaft encoder geometry for any shaft speed profile.

  10. ESF (Exploratory Shaft Facility) impact evaluation report: Volume 1, Final report

    SciTech Connect

    Not Available

    1985-08-01

    This report assesses the impacts of integrating an Exploratory Shaft Facility (ESF) with a high-level nuclear waste repository in salt. A general repository subsurface design is described which complies with the Mine Safety and Health Administration regulations for gassy metal and non-metal mines. This design is combined with the ESF into a site-specific subsurface layout with associated shafts and surface facilities for each of seven sites. An evaluation to identify integration impacts is described for two specific ESF configurations (Cases 1 and 2) for each of the seven sites. These configurations are an ESF which uses two of the full size repository shafts, and an ESF with one 10-ft and one 22-ft diameter shaft. An evaluation of an ESF configuration (Case 3) with two 12-ft diameter shafts at three of the seven sites is also described. These sites are Deaf Smith, Davis Canyon, and Richton Dome. A fourth evaluation (Case 4) for the Deaf Smith site only, addresses a ''fast track'' subsurface development plan to allow waste emplacement by 1998. A fifth evaluation (Case 5), provides site-specific ES locations, for the three sites included in Case 3, which are supportive of a shaft siting study prepared by ONWI.

  11. Endoscope shaft-rigidity control mechanism: "FORGUIDE".

    PubMed

    Loeve, Arjo J; Plettenburg, Dick H; Breedveld, Paul; Dankelman, Jenny

    2012-02-01

    Recent developments in flexible endoscopy and other fields of medical technology have raised the need for compact slender shafts that can be made rigid and compliant at will. A novel compact mechanism, named FORGUIDE, with this functionality was developed. The FORGUIDE shaft rigidifies due to friction between a ring of cables situated between a spring and an inflated tube. A mathematical model for the FORGUIDE mechanism working principle was made and used to obtain understanding of this mechanism, predict the maximum rigidity of a FORGUIDE shaft design, and tune its design variables. The mathematical model gave suggestions for significant performance improvement by fine-tuning the design. A prototype FORGUIDE shaft was built and put to a series of bench tests. These tests showed that the FORGUIDE mechanism provides a reliable and simple way to control the rigidity of a flexible shaft.

  12. Shaft Sinking at the Nevada Test Site, U1h Shaft Project

    SciTech Connect

    B. Briggs; R. Musick

    2001-03-01

    The U1h Shaft Project is a design/build subcontract to construct one 6.1 meter (m) (20 feet (ft)) finished diameter shaft to a depth of 321.6 m (1,055 ft.) at the Nevada Test Site. Atkinson Construction was subcontracted by Bechtel Nevada to construct the U1h Shaft for the U.S. Department of Energy. The project consists of furnishing and installing the sinking plant, construction of the 321.6 m (1,055 ft.) of concrete lined shaft, development of a shaft station at a depth of 297.5 m (976 ft.), and construction of a loading pocket at the station. The outfitting of the shaft and installation of a new hoist may be incorporated into the project at a later date. This paper will describe the design phase, the excavation and lining operation, shaft station construction and the contractual challenges encountered on this project.

  13. Novel Integration Radial and Axial Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    Blumenstock, Kenneth; Brown, Gary

    2000-01-01

    Typically, fully active magnetically suspended systems require one axial and two radial magnetic bearings. Combining radial and axial functions into a single device allows for more compact and elegant packaging. Furthermore, in the case of high-speed devices such as energy storage flywheels, it is beneficial to minimize shaft length to keep rotor mode frequencies as high as possible. Attempts have been made to combine radial and axial functionality, but with certain drawbacks. One approach requires magnetic control flux to flow through a bias magnet reducing control effectiveness, thus resulting in increased resistive losses. This approach also requires axial force producing magnetic flux to flow in a direction into the rotor laminate that is undesirable for minimizing eddy-current losses resulting in rotational losses. Another approach applies a conical rotor shape to what otherwise would be a radial heteropolar magnetic bearing configuration. However, positional non-linear effects are introduced with this scheme and the same windings are used for bias, radial, and axial control adding complexity to the controller and electronics. For this approach, the amount of axial capability must be limited. It would be desirable for an integrated radial and axial magnetic bearing to have the following characteristics; separate inputs for radial and axial control for electronics and control simplicity, all magnetic control fluxes should only flow through their respective air gaps and should not flow through any bias magnets for minimal resistive losses, be of a homopolar design to minimize rotational losses, position related non-linear effects should be minimized, and dependent upon the design parameters, be able to achieve any radial/axial force or power ratio as desired. The integrated radial and axial magnetic bearing described in this paper exhibits all these characteristics. Magnetic circuit design, design equations, and magnetic field modeling results will be presented.

  14. Novel Integrated Radial and Axial Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    Blumenstock, Kenneth A.; Brown, Gary L.; Powers, Edward I. (Technical Monitor)

    2000-01-01

    Typically, fully active magnetically suspended systems require one axial and two radial magnetic bearings. Combining radial and axial functions into a single device allows for more compact and elegant packaging. Furthermore, in the case of high-speed devices such as energy storage flywheels, it is beneficial to minimize shaft length to keep rotor mode frequencies as high as possible. Attempts have been made to combine radial and axial functionality, but with certain drawbacks. One approach requires magnetic control flux to flow through a bias magnet reducing control effectiveness, thus resulting in increased resistive losses. This approach also requires axial force producing magnetic flux to flow in a direction into the rotor laminate that is undesirable for minimizing eddy-current losses resulting in rotational losses. Another approach applies a conical rotor shape to what otherwise would be a radial heteropolar magnetic bearing configuration. However, positional non-linear effects are introduced with this scheme and the same windings are used for bias, radial, and axial control adding complexity to the controller and electronics. For this approach, the amount of axial capability must be limited. It would be desirable for an integrated radial and axial magnetic bearing to have the following characteristics, separate inputs for radial and axial control for electronics and control simplicity, all magnetic control fluxes should only flow through their respective air gaps and should not flow through any bias magnets for minimal resistive losses, be of a homopolar design to minimize rotational losses, position related non-linear effects should be minimized, and dependent upon the design parameters, be able to achieve any radial/axial force or power ratio as desired. The integrated radial and axial magnetic bearing described in this paper exhibits all these characteristics. Magnetic circuit design, design equations, and analysis results will be presented.

  15. Sub-sampling genetic data to estimate black bear population size: A case study

    USGS Publications Warehouse

    Tredick, C.A.; Vaughan, M.R.; Stauffer, D.F.; Simek, S.L.; Eason, T.

    2007-01-01

    Costs for genetic analysis of hair samples collected for individual identification of bears average approximately US$50 [2004] per sample. This can easily exceed budgetary allowances for large-scale studies or studies of high-density bear populations. We used 2 genetic datasets from 2 areas in the southeastern United States to explore how reducing costs of analysis by sub-sampling affected precision and accuracy of resulting population estimates. We used several sub-sampling scenarios to create subsets of the full datasets and compared summary statistics, population estimates, and precision of estimates generated from these subsets to estimates generated from the complete datasets. Our results suggested that bias and precision of estimates improved as the proportion of total samples used increased, and heterogeneity models (e.g., Mh[CHAO]) were more robust to reduced sample sizes than other models (e.g., behavior models). We recommend that only high-quality samples (>5 hair follicles) be used when budgets are constrained, and efforts should be made to maximize capture and recapture rates in the field.

  16. Physical deposit measures and commercial potential: The case of titanium-bearing heavy-mineral deposits

    USGS Publications Warehouse

    Attanasi, E.D.; DeYoung, J.H.

    1988-01-01

    Physical measures of mineral deposit characteristics, such as grade and tonnage, long have been used in both subjective and analytic models to predict favorability of areas for the occurrence of mineral deposits of particular types. After a deposit has been identified, however, the explorationist must decide whether to continue data collection, begin an economic feasibility study, or abandon the prospect. The decision maker can estimate the probability that a deposit will be commercial by examining physical measures. The amount of sampling data required before such a probability estimate can be considered reliable can be determined. A logit probability model estimated from onshore titanium-bearing heavy-mineral deposit data identifies and quantifies the relative influence of a deposit's physical measures on the chances of the deposit becoming commercial. A principal conclusion that can be drawn from the analysis is that, along with a measure of deposit size, the characteristics most important in predicting commercial potential are grades of the constituent minerals. Total heavy-mineral-bearing sand grade or even total titanium grade (without data on constituent mineral grades) are poor predictors of the deposit's commercial potential. ?? 1988 International Association for Mathematical Geology.

  17. Status Update on the Seal/bearing Rotordynamics Test Facility at Case Western Reserve University

    NASA Technical Reports Server (NTRS)

    Adams, Michael L.

    1991-01-01

    The CWRU Seal/Bearing test facility is shown along with the revised force measuring system. This facility has recently been retrofitted with a high pressure, high flow oil system. The high pressure high flow water system remains in place to test seals. Also, a new high flow air system is now installed. Thus, testing to determine static and dynamic properties can now be performed using oil, water, or air on this single facility. The oil system is currently being used to determine rotordynamic properties of a NASA four pocket hydrostatic journal bearing. The revised dual system force measuring configuration is performing with excellent accuracy. That is, the dynamic force measurements are made simultaneously with two independent systems, one with piezoelectric load cells and the other with strain gage load cells. The difference is less than 2 pct. between these two sets of load cell measurements on recent tests with a static eccentricity set close to zero and an orbit radius of 0.0004 inch. The extracted stiffness, damping and inertia coefficients is given for the test conditions shown, as extracted from the two independent dynamic force measurements.

  18. The new low nitrogen steel LNS -- A material for advanced aircraft engine and aerospace bearing applications

    SciTech Connect

    Berns, H.; Ebert, F.J.

    1998-12-31

    Development tendencies for future aircraft jet engines require new design concepts for rolling element bearings because of an overall increase of loads, temperatures, rotational speeds and the use of new high temperature lubricants. This paper reviews some of the key parameters which in the past led to the development and application of the known aircraft bearing steels such as M50, M50 NiL and recently Cronidur 30{reg_sign} (AMS 5898). The performance limits of the currently used aerospace bearing steels and the increasing demands on bearing performance for future aerospace applications gave the impact to the design of a new corrosion resistant steel grade of the nitrogen alloyed type, which is suitable for case hardening by nitrogen--the so called Low nitrogen steel (LNS). The development of the alloy (US pat. 5,503,797), the attainable properties and the corresponding heat treatment process are presented. Achievable hardness, case depth, residual stress pattern and corrosion resistance prove the new LNS to be a promising candidate for the next generation of aircraft engine bearings and for advanced, integrated bearing-gear-shaft design concepts.

  19. Fault Tolerant Magnetic Bearing Testing and Conical Magnetic Bearing Development for Extreme Temperature Environments

    NASA Technical Reports Server (NTRS)

    Keith, Theo G., Jr.; Clark, Daniel

    2004-01-01

    During the six month tenure of the grant, activities included continued research of hydrostatic bearings as a viable backup-bearing solution for a magnetically levitated shaft system in extreme temperature environments (1000 F), developmental upgrades of the fault-tolerant magnetic bearing rig at the NASA Glenn Research Center, and assisting in the development of a conical magnetic bearing for extreme temperature environments, particularly turbomachinery. It leveraged work from the ongoing Smart Efficient Components (SEC) and the Turbine-Based Combined Cycle (TBCC) program at NASA Glenn Research Center. The effort was useful in providing technology for more efficient and powerful gas turbine engines.

  20. Fault Tolerant Magnetic Bearing Testing and Conical Magnetic Bearing Development for Extreme Temperature Environments

    NASA Technical Reports Server (NTRS)

    Keith, Theo G., Jr.; Clark, Daniel

    2004-01-01

    During the six month tenure of the grant, activities included continued research of hydrostatic bearings as a viable backup-bearing solution for a magnetically levitated shaft system in extreme temperature environments (1000 F), developmental upgrades of the fault-tolerant magnetic bearing rig at the NASA Glenn Research Center, and assisting in the development of a conical magnetic bearing for extreme temperature environments, particularly turbomachinery. It leveraged work from the ongoing Smart Efficient Components (SEC) and the Turbine-Based Combined Cycle (TBCC) program at NASA Glenn Research Center. The effort was useful in providing technology for more efficient and powerful gas turbine engines.

  1. Hybrid bearings for turbopumps and the like

    NASA Technical Reports Server (NTRS)

    Justak, John F. (Inventor); Owens, Gregg R. (Inventor)

    1994-01-01

    In rocket engines power is usually obtained by burning fuel and oxidizer which are mixed, pressurized, and directed to a combustion chamber by means of turbopumps. Roller bearings are generally used in these turbopumps, but because of bearing demands hydrostatic bearings were proposed. The use of such bearings is quite feasible because during flight hydrostatic lubrication can reduce roller bearing wear. A disadvantage of such proposals is that during startup, acceleration, and shutdown high pressure fluids are not available for hydrostatic bearings. The fluid lubrication film is not always present in bearings of turbopumps. During these periods a second bearing is required to carry the load. This requirement suggests the use of hybrid bearings in rocket engine turbopumps. Such duplex bearings were provided, but when their inner races are keyed to the shaft or journal two of them are required. And such duplex bearings do not wear evenly. A hybrid hydrostatic-rolling element bearing was provided wherein the rolling element bearing is locked on the stationary housing rather than on the rotating journal.

  2. Hybrid bearings for turbopumps and the like

    NASA Astrophysics Data System (ADS)

    Justak, John F.; Owens, Gregg R.

    1993-01-01

    In rocket engines power is usually obtained by burning fuel and oxidizer which are mixed, pressurized, and directed to a combustion chamber by means of turbopumps. Roller bearings are generally used in these turbopumps, but because of bearing demands hydrostatic bearings were proposed. The use of such bearings is quite feasible because during flight hydrostatic lubrication can reduce roller bearing wear. A disadvantage of such proposals is that during startup, acceleration, and shutdown high pressure fluids are not available for hydrostatic bearings. The fluid lubrication film is not always present in bearings of turbopumps. During these periods a second bearing is required to carry the load. This requirement suggests the use of hybrid bearings in rocket engine turbopumps. Such duplex bearings were provided, but when their inner races are keyed to the shaft or journal two of them are required. And such duplex bearings do not wear evenly. A hybrid hydrostatic-rolling element bearing was provided wherein the rolling element bearing is locked on the stationary housing rather than on the rotating journal.

  3. Hybrid bearings for turbopumps and the like

    NASA Astrophysics Data System (ADS)

    Justak, John F.; Owens, Gregg R.

    1994-09-01

    In rocket engines power is usually obtained by burning fuel and oxidizer which are mixed, pressurized, and directed to a combustion chamber by means of turbopumps. Roller bearings are generally used in these turbopumps, but because of bearing demands hydrostatic bearings were proposed. The use of such bearings is quite feasible because during flight hydrostatic lubrication can reduce roller bearing wear. A disadvantage of such proposals is that during startup, acceleration, and shutdown high pressure fluids are not available for hydrostatic bearings. The fluid lubrication film is not always present in bearings of turbopumps. During these periods a second bearing is required to carry the load. This requirement suggests the use of hybrid bearings in rocket engine turbopumps. Such duplex bearings were provided, but when their inner races are keyed to the shaft or journal two of them are required. And such duplex bearings do not wear evenly. A hybrid hydrostatic-rolling element bearing was provided wherein the rolling element bearing is locked on the stationary housing rather than on the rotating journal.

  4. Estimating Allee dynamics before they can be observed: polar bears as a case study.

    PubMed

    Molnár, Péter K; Lewis, Mark A; Derocher, Andrew E

    2014-01-01

    Allee effects are an important component in the population dynamics of numerous species. Accounting for these Allee effects in population viability analyses generally requires estimates of low-density population growth rates, but such data are unavailable for most species and particularly difficult to obtain for large mammals. Here, we present a mechanistic modeling framework that allows estimating the expected low-density growth rates under a mate-finding Allee effect before the Allee effect occurs or can be observed. The approach relies on representing the mechanisms causing the Allee effect in a process-based model, which can be parameterized and validated from data on the mechanisms rather than data on population growth. We illustrate the approach using polar bears (Ursus maritimus), and estimate their expected low-density growth by linking a mating dynamics model to a matrix projection model. The Allee threshold, defined as the population density below which growth becomes negative, is shown to depend on age-structure, sex ratio, and the life history parameters determining reproduction and survival. The Allee threshold is thus both density- and frequency-dependent. Sensitivity analyses of the Allee threshold show that different combinations of the parameters determining reproduction and survival can lead to differing Allee thresholds, even if these differing combinations imply the same stable-stage population growth rate. The approach further shows how mate-limitation can induce long transient dynamics, even in populations that eventually grow to carrying capacity. Applying the models to the overharvested low-density polar bear population of Viscount Melville Sound, Canada, shows that a mate-finding Allee effect is a plausible mechanism for slow recovery of this population. Our approach is generalizable to any mating system and life cycle, and could aid proactive management and conservation strategies, for example, by providing a priori estimates of minimum

  5. Estimating Allee Dynamics before They Can Be Observed: Polar Bears as a Case Study

    PubMed Central

    Molnár, Péter K.; Lewis, Mark A.; Derocher, Andrew E.

    2014-01-01

    Allee effects are an important component in the population dynamics of numerous species. Accounting for these Allee effects in population viability analyses generally requires estimates of low-density population growth rates, but such data are unavailable for most species and particularly difficult to obtain for large mammals. Here, we present a mechanistic modeling framework that allows estimating the expected low-density growth rates under a mate-finding Allee effect before the Allee effect occurs or can be observed. The approach relies on representing the mechanisms causing the Allee effect in a process-based model, which can be parameterized and validated from data on the mechanisms rather than data on population growth. We illustrate the approach using polar bears (Ursus maritimus), and estimate their expected low-density growth by linking a mating dynamics model to a matrix projection model. The Allee threshold, defined as the population density below which growth becomes negative, is shown to depend on age-structure, sex ratio, and the life history parameters determining reproduction and survival. The Allee threshold is thus both density- and frequency-dependent. Sensitivity analyses of the Allee threshold show that different combinations of the parameters determining reproduction and survival can lead to differing Allee thresholds, even if these differing combinations imply the same stable-stage population growth rate. The approach further shows how mate-limitation can induce long transient dynamics, even in populations that eventually grow to carrying capacity. Applying the models to the overharvested low-density polar bear population of Viscount Melville Sound, Canada, shows that a mate-finding Allee effect is a plausible mechanism for slow recovery of this population. Our approach is generalizable to any mating system and life cycle, and could aid proactive management and conservation strategies, for example, by providing a priori estimates of minimum

  6. Evolution and use of combined mechanical and thermal codes for cryogenic turbopump bearings

    NASA Technical Reports Server (NTRS)

    Cody, Joe C.; Marty, David E.; Moore, James D.

    1988-01-01

    Shaft bearing system analysis codes were developed, improved, and used to investigate Space Shuttle Main Engine (SSME) Liquid Oxygen (LOX) turbopump bearing problems, and to support the Marshall Space Flight Center Bearing and Seal Materials Test (BSMT) program. Thermal network modeling uses the SINDA thermal code, and the modeling of bearing quasi-dynamic characteristics uses the SHABERTH bearing/shaft code. These codes are solved concurrently for a bearing/shaft system using software developed for this purpose. Simulation of the SSME LOX turbopump turbine and pump end bearings and the MSFC BSMT operating in liquid nitrogen (LN sub 2) and LOX was done. The thermal network models include the bearing components, bearing carriers, shaft, housing, frictional heat, and viscous fluid energy. A cage model was included to account for heat generation between the cage and rolling elements. Since most bearing surfaces operate at temperatures well above the coolant saturation temperature, and move at high speed relative to the coolant, forced convection boiling is the dominant mechanism for heat removal. Improved modeling of forced convection film boiling was incorporated to take into account the local vapor generation at the high temperature surfaces. Rearing preloads in the pump and tester are provided by preload springs. As bearing operating clearances and contact angles change due to thermal effects and loading, the bearing preload changes with these varying conditions. These characteristics were modeled and are included in the overall system models. Results from these models indicate an operational limit which, if exceeded, predicts a thermal excursion.

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

    PubMed

    Tse, Peter W; Wang, Dong

    2017-02-14

    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.

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

    PubMed Central

    Tse, Peter W.; Wang, Dong

    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 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. PMID:28216586

  9. Subtrochanteric Femoral Fracture during Trochanteric Nailing for the Treatment of Femoral Shaft Fracture

    PubMed Central

    Oh, Chi Hun; Yi, Ju Won

    2013-01-01

    We report on three cases of subtrochanteric femoral fractures during trochanteric intramedullary nailing for the treatment of femoral shaft fractures. Trochanteric intramedullary nails, which have a proximal lateral bend, are specifically designed for trochanteric insertion. When combined with the modified insertion technique, trochanteric intramedullary nails reduce iatrogenic fracture comminution and varus malalignment. We herein describe technical aspects of trochanteric intramedullary nailing for femoral shaft fractures to improve its application and prevent implant-derived complications. PMID:24009910

  10. Effect of Bearings on Vibration in Rotating Machinery

    NASA Astrophysics Data System (ADS)

    Daniel, Rudrapati Victor; Amit Siddhappa, Savale; Bhushan Gajanan, Savale; Vipin Philip, S.; Paul, P. Sam

    2017-08-01

    In rotary machines vibration is an inherent phenomenon which has the tendency to affect required performance. Amongst the different parameters that affect vibration, selection of appropriate bearing is the most critical component. In this work the effect of different types of bearing on vibration in rotary machines is studied and the magnitude of vibration produced by use of different set of bearings under the same condition of loads and rotational speeds were investigated. Bearings considered in this work were ball bearing, tapered roller bearing, thrust bearing and shaft material considered is of mild steel. From experimental result, it was noted that tapered roller bearing gives the highest amplitude of vibration among all the three bearings whereas the ball bearing gives least amplitude under similar operating conditions.

  11. Two High-Temperature Foil Journal Bearings

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    2006-01-01

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

  12. Shaft sealing issue in CO2 storage sites

    NASA Astrophysics Data System (ADS)

    Dieudonné, A.-C.; Charlier, R.; Collin, F.

    2012-04-01

    Carbon capture and storage is an innovating approach to tackle climate changes through the reduction of greenhouse gas emissions. Deep saline aquifers, depleted oil and gas reservoirs and unmineable coal seams are among the most studied reservoirs. However other types of reservoir, such as abandonned coal mines, could also be used for the storage of carbon dioxide. In this case, the problem of shaft sealing appears to be particularly critical regarding to the economic, ecologic and health aspects of geological storage. The purpose of the work is to study shaft sealing in the framework of CO2 storage projects in abandoned coal mines. The problem of gas transfers around a sealing system is studied numerically using the finite elements code LAGAMINE, which has been developped for 30 years at the University of Liege. A coupled hydro-mechanical model of unsaturated geomaterials is used for the analyses. The response of the two-phase flow model is first studied through a simple synthetic problem consisting in the injection of gas in a concrete-made column. It stands out of this first modeling that the advection of the gas phase represents the main transfer mechanism of CO2 in highly unsaturated materials. Furthermore the setting of a bentonite barrier seal limits considerably the gas influx into the biosphere. A 2D axisymetric hydromechanical modeling of the Anderlues natural gas storage site is then performed. The geological and hydrogeological contexts of the site are used to define the problem, for the initial and boundary conditions, as well as the material properties. In order to reproduce stress and water saturation states in the shale before CO2 injection in the mine, different phases corresponding to the shaft sinking, the mining and the set up of the sealing system are simulated. The system efficiency is then evaluated by simulating the CO2 injection with the imposed pressure at the shaft wall. According to the modeling, the low water saturation of concrete and

  13. Stress Analysis of Pallet Lever Shaft

    DTIC Science & Technology

    1976-03-01

    AD-A03/ ^17 FA-TR-76028 STI(ESS ANALYSIS OF PALLET LEVER SHAFT by ?aul F. Gordon Fee Hen Lee Ramesh Kajaria TECHNICAL LIBRARY March 1976...for FA Report TR-76028 (March 1976) tITLE: Stress Analysis of Pallet Lever Shaft "AUTHORS: Paul F. Gordon, Fee M. Lee, Ramesh Kajaria 𔄃...force of magnitude Fw and a couple (see Fig 4, page 13). This force, Fw, acts on the shaft at the center of the pallet , and its distance M, from

  14. Robust design optimization of the vibrating rotor-shaft system subjected to selected dynamic constraints

    NASA Astrophysics Data System (ADS)

    Stocki, R.; Szolc, T.; Tauzowski, P.; Knabel, J.

    2012-05-01

    The commonly observed nowadays tendency to weight minimization of rotor-shafts of the rotating machinery leads to a decrease of shaft bending rigidity making a risk of dangerous stress concentrations and rubbing effects more probable. Thus, a determination of the optimal balance between reducing the rotor-shaft weight and assuring its admissible bending flexibility is a major goal of this study. The random nature of residual unbalances of the rotor-shaft as well as randomness of journal-bearing stiffness have been taken into account in the framework of robust design optimization. Such a formulation of the optimization problem leads to the optimal design that combines an acceptable structural weight with the robustness with respect to uncertainties of residual unbalances - the main source of bending vibrations causing the rubbing effects. The applied robust optimization technique is based on using Latin hypercubes in scatter analysis of the vibration response. The so-called optimal Latin hypercubes are used as experimental plans for building kriging approximations of the objective and constraint functions. The proposed method has been applied for the optimization of the typical single-span rotor-shaft of the 8-stage centrifugal compressor.

  15. Research study for effects of case flexibility on bearing loads and rotor stability

    NASA Technical Reports Server (NTRS)

    Fenwick, J. R.; Tarn, R. B.

    1984-01-01

    Methods to evaluate the effect of casing flexibility on rotor stability and component loads were developed. Recent Rocketdyne turbomachinery was surveyed to determine typical properties and frequencies versus running speed. A small generic rotor was run with a flexible case with parametric variations in casing properties for comparison with a rotor attached to rigid supports. A program for the IBM personal computer for interactive evaluation of rotors and casings is developed. The Root locus method is extended for use in rotor dynamics for symmetrical systems by transforming all motion and coupling into a single plane and using a 90 degree criterion when plotting loci.

  16. The decision, implementation and assessment of a credit-bearing activity class by faculty in residence: A case study.

    PubMed

    Callahan, Janet; Harrison, Geoff; Humphrey, Michael; Sielaff, Cala; Wintrow, Melissa

    2015-01-01

    This case study reports on a programmatic decision to require a credit-bearing course that was made by Faculty in Residence (FIR), including its implementation and results over a two-year period from 2010-2012. The focus is on FIR and on the impact of their decision upon the students enrolled in their Living Learning Communities (LLCs). The credit-bearing course was a Kinesiology Activities class taken by all seven LLCs at Boise State University. Anonymous feedback from students was obtained via end of semester surveys; results were used to improve the course. Survey feedback was analyzed to assess the value students perceived to have gained from the course. The majority of students reported gaining value from the class. Students noted that it positively affected their time management/personal accountability, that it decreased their stress level and that it increased their awareness of the Recreational Center offerings. Some students were critical of the course, reporting little to no value or even resentment about the course requirement. The decision, implementation and improvements of the course required faculty leadership and full participation of all LLCs; perceptions of the FIR in terms of the effects of adding the required course on their LLC are reported.

  17. Magnetic bearings with zero bias

    NASA Technical Reports Server (NTRS)

    Brown, Gerald V.; Grodsinsky, Carlos M.

    1991-01-01

    A magnetic bearing operating without a bias field has supported a shaft rotating at speeds up to 12,000 rpm with the usual four power supplies and with only two. A magnetic bearing is commonly operated with a bias current equal to half of the maximum current allowable in its coils. This linearizes the relation between net force and control current and improves the force slewing rate and hence the band width. The steady bias current dissipates power, even when no force is required from the bearing. The power wasted is equal to two-thirds of the power at maximum force output. Examined here is the zero bias idea. The advantages and disadvantages are noted.

  18. Thrust to torque converter, particularly for coupling a reciprocating shaft to a rotary electrical generator or the like

    SciTech Connect

    Otters, J.L.

    1990-04-03

    This patent describes a mechanical linear-to-rotary motion converter. It comprises: a housing; a ball bearing input screw reciprocally mounted to the housing; a rotor; a first ball bearing nut coupling the input screw through a first overrunning clutch for turning the rotor in a given sense of rotation for a first direction of movement of the screw; a second ball bearing nut coupling the input screw through a reversing gear arrangement and a second overrunning clutch for turning the rotor in a given sense of rotation for an opposite direction of movement of the shaft; the first and second ball bearing nuts alternately driving the rotor for continuous rotation in the given sense responsive to linear reciprocating motion of the input shaft.

  19. Case Study: From Gummy Bears to Celery Stalks--Diffusion and Osmosis

    ERIC Educational Resources Information Center

    Bonney, Kevin M.

    2014-01-01

    This article describes an interrupted case study that intersperses information about diffusion and osmosis with content review and knowledge application questions, as well as a simple experiment that can be conducted without the use of a laboratory. The case study was developed for use in an introductory undergraduate biology course. The case…

  20. Case Study: From Gummy Bears to Celery Stalks--Diffusion and Osmosis

    ERIC Educational Resources Information Center

    Bonney, Kevin M.

    2014-01-01

    This article describes an interrupted case study that intersperses information about diffusion and osmosis with content review and knowledge application questions, as well as a simple experiment that can be conducted without the use of a laboratory. The case study was developed for use in an introductory undergraduate biology course. The case…

  1. Can hunting data be used to estimate unbiased population parameters? A case study on brown bears

    PubMed Central

    Van de Walle, Joanie; Zedrosser, Andreas; Swenson, Jon E.; Pelletier, Fanie

    2016-01-01

    Quantifying temporal changes in harvested populations is critical for applied and fundamental research. Unbiased data are required to detect true changes in phenotypic distribution or population size. Because of the difficulty of collecting detailed individual data from wild populations, data from hunting records are often used. Hunting records, however, may not represent a random sample of a population. We aimed to detect and quantify potential bias in hunting records. We compared data from a long-term monitoring project with hunting records of brown bears (Ursus arctos) in Sweden and investigated temporal trends (1996–2013) in the ratio of yearlings to adult females, yearling mass and adult female mass. Data from hunting records underestimated the decline in yearling and adult female mass over time, most likely owing to the legal protection of family groups from hunting, but reflected changes in the ratio of yearlings to adult females more reliably. Although hunting data can be reliable to approximate population abundance in some circumstances, hunting data can represent a biased sample of a population and should be used with caution in management and conservation decisions. PMID:27303052

  2. Can hunting data be used to estimate unbiased population parameters? A case study on brown bears.

    PubMed

    Leclerc, Martin; Van de Walle, Joanie; Zedrosser, Andreas; Swenson, Jon E; Pelletier, Fanie

    2016-06-01

    Quantifying temporal changes in harvested populations is critical for applied and fundamental research. Unbiased data are required to detect true changes in phenotypic distribution or population size. Because of the difficulty of collecting detailed individual data from wild populations, data from hunting records are often used. Hunting records, however, may not represent a random sample of a population. We aimed to detect and quantify potential bias in hunting records. We compared data from a long-term monitoring project with hunting records of brown bears (Ursus arctos) in Sweden and investigated temporal trends (1996-2013) in the ratio of yearlings to adult females, yearling mass and adult female mass. Data from hunting records underestimated the decline in yearling and adult female mass over time, most likely owing to the legal protection of family groups from hunting, but reflected changes in the ratio of yearlings to adult females more reliably. Although hunting data can be reliable to approximate population abundance in some circumstances, hunting data can represent a biased sample of a population and should be used with caution in management and conservation decisions. © 2016 The Authors.

  3. Two-stitch technique for distal shaft hypospadias repair.

    PubMed

    Herman, Oscar; Heller, Lior; Dorenbaum, Arye; Westreich, Melvyn

    2002-02-01

    The authors present a new technique for distal shaft hypospadias repair using a flip flap fashioned with only two stitches. In raising the flap, the tissues lateral and proximal to the flap are undermined but there is no undermining beneath the flap. The flap is sutured up to the glans with two 4-0 Vicryl sutures. No sutures are placed at the lateral edges of the flap to create the "tube" of the neo-urethra, and no postoperative urinary drainage is used. Thirty-three children with distal shaft hypospadias underwent the "two-stitch" flip flap operation. The complications were one fistula and one case of urinary retention. The technique is an easy method for reconstructing distal penile hypospadias with a very low rate of complications and is suitable for an outpatient surgical setting.

  4. Estimation of bearing contact angle in-situ by X-ray kinematography

    NASA Technical Reports Server (NTRS)

    Fowler, P. H.; Manders, F.

    1982-01-01

    The mounted, preloaded contact angle of the structural bearings in the assembled design mechanical assembly was measured. A modification of the Turns method is presented, based upon the clarity and definition of moving parts achieved with X-ray technique and cinematic display. Contact angle is estimated by counting the number of bearings passing a given point as a function of number of turns of the shaft. Ball and pitch diameter variations are discussed. Ball train and shaft angle uncertainties are also discussed.

  5. Investigation of Shaft Voltage in Wind Turbine Systems with Induction Generators

    NASA Astrophysics Data System (ADS)

    Adabi, Jafar; Zare, Firuz

    This paper presents the analysis of shaft voltage in different configurations of a doubly fed induction generator (DFIG) and an induction generator (IG) with a back-to-back inverter in wind turbine applications. Detailed high frequency model of the proposed systems have been developed based on existing capacitive couplings in IG & DFIG structures and common mode voltage sources. In this research work, several arrangements of DFIG based wind energy conversion systems (WES) are investigated in case of shaft voltage calculation and its mitigation techniques. Placements of an LC line filter in different locations and its effects on shaft voltage elimination are studied via Mathematical analysis and simulations. A pulse width modulation (PWM) technique and a back-to-back inverter with a bidirectional buck converter have been presented to eliminate the shaft voltage in a DFIG wind turbine.

  6. Documentation and verification of the SHAFT code; Yucca Mountain Site Characterization Project

    SciTech Connect

    St.John, C.M.

    1991-12-01

    The SHAFT code incorporates equations to compute stresses in a shaft liner when the rock through which a shaft passes is subject to known three-dimensional states of stress or strain. The deformation modes considered are hoop deformation, axial deformation, and shear on a plane normal to the shaft axis. Interaction between the liner and the soil and rock is considered, and it is assumed that the liner is in place before loading is applied. This code is intended to be used interactively but creates a permanent record complete with necessary quality assurance information. The code has been carefully verified for the case of generalized plane strain, in which an arbitrary axial strain can be defined. It may also be used for plane stress analysis. Output is given in the form of stresses at selected sample points in the linear and the rock and a simple graphical representation of the distribution of stress through the liner. 12 figs., 13 tabs.

  7. 30 CFR 56.19100 - Shaft landing gates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft landing gates. 56.19100 Section 56.19100... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Personnel Hoisting Shafts § 56.19100 Shaft landing gates. Shaft landings shall be equipped with substantial safety gates...

  8. 30 CFR 57.19109 - Shaft inspection and repair.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft inspection and repair. 57.19109 Section 57.19109 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Shafts § 57.19109 Shaft inspection and repair. Shaft inspection and repair work in vertical...

  9. 30 CFR 56.19109 - Shaft inspection and repair.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft inspection and repair. 56.19109 Section 56.19109 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Shafts § 56.19109 Shaft inspection and repair. Shaft inspection and repair work in vertical...

  10. 30 CFR 75.1711-1 - Sealing of shaft openings.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Sealing of shaft openings. 75.1711-1 Section 75... shaft openings. Shaft openings required to be sealed under § 75.1711 shall be effectively capped or filled. Filling shall be for the entire depth of the shaft and, for the first 50 feet from the bottom...

  11. 30 CFR 56.19104 - Clearance at shaft stations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Clearance at shaft stations. 56.19104 Section 56.19104 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Shafts § 56.19104 Clearance at shaft stations. Suitable clearance at shaft stations shall...

  12. 30 CFR 57.19104 - Clearance at shaft stations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Clearance at shaft stations. 57.19104 Section 57.19104 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Shafts § 57.19104 Clearance at shaft stations. Suitable clearance at shaft stations shall...

  13. 30 CFR 77.1911 - Ventilation of slopes and shafts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Ventilation of slopes and shafts. 77.1911... COAL MINES Slope and Shaft Sinking § 77.1911 Ventilation of slopes and shafts. (a) All slopes and shafts shall be ventilated by mechanical ventilation equipment during development. Such equipment...

  14. 30 CFR 77.1911 - Ventilation of slopes and shafts.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Ventilation of slopes and shafts. 77.1911... COAL MINES Slope and Shaft Sinking § 77.1911 Ventilation of slopes and shafts. (a) All slopes and shafts shall be ventilated by mechanical ventilation equipment during development. Such equipment...

  15. 30 CFR 77.1911 - Ventilation of slopes and shafts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Ventilation of slopes and shafts. 77.1911... COAL MINES Slope and Shaft Sinking § 77.1911 Ventilation of slopes and shafts. (a) All slopes and shafts shall be ventilated by mechanical ventilation equipment during development. Such equipment...

  16. Flexible shaft and roof drilling system

    SciTech Connect

    Blanz, J.H.

    1981-09-22

    A system for drilling holes in the roof of a mine has a flexible shaft with a pair of oppositely wound, coaxial flat bands. One of the flat bands defines an inner spring that is wound right handed into a helical configuration, adjacent convolutions being in nesting relationship to one another. The other flat band defines an outer spring that is wound left handed into a helical configuration about the inner band, adjacent convolutions being nesting relationship with one another. A transition member that is configured to hold a rock bit is mounted to one end of the flexible shaft. When torque and thrust are applied to the flexible shaft by a driver, the inner spring expands outwardly and the outer spring contracts inwardly to form a relatively rigid shaft.

  17. Development of variable-shaft-speed alternator

    NASA Astrophysics Data System (ADS)

    Rothbart, G.; Fullwood, R.

    1982-02-01

    A variable shaft speed alternator (VSSA) consists of an ordinary unmodified 1-1/2 Hp wound-rotor motor, with polyphase excitation controlled by solid state switching and a hybrid of analog and digital circuitry. This circuitry senses both shaft speed and line phase resulting in logic levels which control the current flow in each rotor coil. A first order polynomial was found using the least-squares regression method which accurately expressed the relationship among shaft speed, excitation power, and output power, VSSA torque was inferred from observations to be proportional to output power. Efficiency for converting mechanical power to electrical was inferred over a range of shaft speeds. A break-even speed below which no net power is produced was observed to be 0.375 of the synchronous speed for all output power levels. Similar behavior was observed with power fed to the power network (grid). Additional measurements involved VSSA performance at various power factors.

  18. Reliability assessment of underground shaft closure

    SciTech Connect

    Fossum, A.F.

    1994-12-31

    The intent of the WIPP, being constructed in the bedded geologic salt deposits of Southeastern New Mexico, is to provide the technological basis for the safe disposal of radioactive Transuranic (TRU) wastes generated by the defense programs of the United States. In determining this technological basis, advanced reliability and structural analysis techniques are used to determine the probability of time-to-closure of a hypothetical underground shaft located in an argillaceous salt formation and filled with compacted crushed salt. Before being filled with crushed salt for sealing, the shaft provides access to an underground facility. Reliable closure of the shaft depends upon the sealing of the shaft through creep closure and recompaction of crushed backfill. Appropriate methods are demonstrated to calculate cumulative distribution functions of the closure based on laboratory determined random variable uncertainty in salt creep properties.

  19. New motor shaft angular accelerometer concept

    NASA Technical Reports Server (NTRS)

    Smetana, F. O.

    1973-01-01

    Concept permits measurement of the acceleration of continuously rotating shafts without use of slip rings or telemetry and with little additional inertial load. Concept has application in servomotor control circuits and easy-to-fly airplane controls.

  20. Flexible shaft and roof drilling system

    DOEpatents

    Blanz, John H.

    1981-01-01

    A system for drilling holes in the roof of a mine has a flexible shaft with a pair of oppositely wound, coaxial flat bands. One of the flat bands defines an inner spring that is wound right handed into a helical configuration, adjacent convolutions being in nesting relationship to one another. The other flat band defines an outer spring that is wound left handed into a helical configuration about the inner band, adjacent convolutions being nesting relationship with one another. A transition member that is configured to hold a rock bit is mounted to one end of the flexible shaft. When torque and thrust are applied to the flexible shaft by a driver, the inner spring expands outwardly and the outer spring contracts inwardly to form a relatively rigid shaft.

  1. Finite-Difference Solutions of the Alternate Turbopump Development High-Pressure Oxidizer Turbopump Pump-End Ball-Bearing Cavity Flows

    NASA Technical Reports Server (NTRS)

    Benjamin, Theodore G.; Garcia, Roberto; Mcconnaughey, Paul K.; Wang, Ten-See; Vu, Bruce T.; Dakhoul, Youssef

    1993-01-01

    These analyses were undertaken to aid in the understanding of flow phenomena in the Alternate Turbopump Development (ATD) High-pressure Oxidizer Turbopump (HPOTP) Pump-end ball bearing (PEBB) cavities and their roles in turbopump vibration initiation and bearing distress. This effort was being performed to provide timely support to the program in a decision as to whether or not the program should be continued. In the first case, it was determined that a change in bearing through flow had no significant effect on axial preload. This was a follow-on to a previous study which had resulted in a redesign of the bearing exit cavity which virtually eliminated bearing axial loading. In the second case, a three-dimensional analysis of the inner-race-guided cage configuration was performed so as to determine the pressure distribution on the outer race when the shaft is 0.0002 inches off-center. The results indicate that there is virtually no circumferential pressure difference caused by the offset to contribute to bearing tilt. In the third case, axisymmetric analyses were performed on an outer-race guided cage configuration to determine the magnitude of tangential flow entering the bearing. The removed-shoulder case was analyzed as was the static diverter case. A third analysis where the preload spring was shielded by a sheet of metal for the baseline case was also performed. It was determined that the swirl entering the bearing was acceptable and the project decided to use the outer-race-guided cage configuration. In the fourth case, more bearing configurations were analyzed. These analyses included thermal modeling so as to determine the added benefit of injecting colder fluid directly onto the bearing inner-race contact area. The results of these analyses contributed to a programmatic decision to include coolant injection in the design.

  2. Current Concepts in Paediatric Femoral Shaft Fractures

    PubMed Central

    John, Rakesh; Sharma, Siddhartha; Raj, Gopinathan Nirmal; Singh, Jujhar; C., Varsha; RHH, Arjun; Khurana, Ankit

    2017-01-01

    Pediatric femoral shaft fractures account for less than 2% of all fractures in children. However, these are the most common pediatric fractures necessitating hospitalization and are associated with prolonged hospital stay, prolonged immobilization and impose a significant burden on the healthcare system as well as caregivers. In this paper, the authors present a comprehensive review of epidemiology, aetiology, classification and managemement options of pediatric femoral shaft fractures. PMID:28603567

  3. Prognosis and Management of Congenital Hair Shaft Disorders with Fragility-Part I.

    PubMed

    Singh, Gaurav; Miteva, Mariya

    2016-09-01

    Hair shaft disorders are characterized by congenital or acquired abnormalities of the hair shaft. The objective was to review the literature regarding the prognosis and treatment options of hair shaft disorders. We used keywords in the search engines PubMed and Medline to identify all publications in the English language related to the prognosis and management of hair shaft disorders. Data were extracted from 96 articles that met search criteria. Findings were limited to case reports and small case series, as no studies were found. Disorders that improve in childhood include pili torti, trichorrhexis invaginata, wooly hair, and pili trianguli et canaliculi. Others, such as trichorrhexis nodosa, monilethrix, pili annulati, and pili bifurcati improve with minoxidil. Oral retinoids have improved hair abnormalities in trichorrhexis invaginata and monilethrix. There is no specific treatment for congenital hair shaft abnormalities. Gentle hair care is the mainstay of care for hair shaft disorders associated with fragility. Practices for gentle care include no brushing, backcombing, chemical products, tight braids, heat exposure, or mechanical grooming. Any inherited or congenital disorder requires genetic counseling as part of management.

  4. Prognosis and Management of Congenital Hair Shaft Disorders without Fragility-Part II.

    PubMed

    Singh, Gaurav; Miteva, Mariya

    2016-09-01

    Hair shaft disorders are characterized by congenital or acquired abnormalities of the hair shaft. The objective of this study was to review the literature regarding the prognosis and treatment options for hair shaft disorders. We used keywords in the search engines PubMed and Medline to identify all publications in English related to the prognosis and management of hair shaft disorders. Data were extracted from 96 articles that met search criteria. Findings were limited to case reports and small case series, as no studies were found. Disorders that improve in childhood include pili torti, trichorrhexis invaginata, woolly hair, and pili trianguli et canaliculi. Others, such as trichorrhexis nodosa, monilethrix, pili annulati, and pili bifurcati, improve with minoxidil. Oral retinoids have been found to improve hair abnormalities in trichorrhexis invaginata and monilethrix. There is no specific treatment for congenital hair shaft abnormalities. Gentle hair care is the mainstay of care for hair shaft disorders associated with fragility. Practices for gentle care include no brushing, backcombing, chemical products, tight braids, heat exposure, or mechanical grooming. Furthermore, any inherited or congenital disorder requires genetic counseling as part of management.

  5. ESF (Exploratory Shaft Facility) impact evaluation report: Volume 2: Final report

    SciTech Connect

    Not Available

    1985-08-01

    This report assesses the impacts of integrating an Exploratory Shaft Facility (ESF) with a high-level nuclear waste repository in salt. An evaluation to identify integration impacts is described for two specific ESF configurations (Cases 1 and 2) for each of the seven sites. These configurations are an ESF which uses two of the full size repository shafts, and an ESF with one 10-ft and one 22-ft diameter shaft. An evaluation of an ESF configuration (Case 3) with two 12-ft diameter shafts at three of the seven sites is also described. These sites are Deaf Smith, Davis Canyon, and Richton Dome. A fourth evaluation (Case 4) for the Deaf Smith site only, addresses a ''fast track'' subsurface development plan to allow waste emplacement by 1998. A fifth evaluation (Case 5), provides site-specific ES locations, for the three sites included in Case 3, which are supportive of a shaft siting study prepared by ONWI. The report presents development schedules depicting construction activities and time frames commencing with receipt of the repository Construction Authorization and proceeding to initiation of emplacement operations. These schedules are site specific and are presented for each of the five cases.

  6. Gear bearings

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    2003-01-01

    A gear bearing having a first gear and a second gear, each having a plurality of teeth. Each gear operates on two non-parallel surfaces of the opposing gear teeth to perform both gear and bearing functions simultaneously. The gears are moving at substantially the same speed at their contact points. The gears may be roller gear bearings or phase-shifted gear bearings, and may be arranged in a planet/sun system or used as a transmission.

  7. Modeling of rolling element bearing mechanics. Theoretical manual

    NASA Technical Reports Server (NTRS)

    Merchant, David H.; Greenhill, Lyn M.

    1994-01-01

    This report documents the theoretical basis for the Rolling Element Bearing Analysis System (REBANS) analysis code which determines the quasistatic response to external loads or displacement of three types of high-speed rolling element bearings: angular contact ball bearings; duplex angular contact ball bearings; and cylindrical roller bearings. The model includes the effects of bearing ring and support structure flexibility. It is comprised of two main programs: the Preprocessor for Bearing Analysis (PREBAN) which creates the input files for the main analysis program; and Flexibility Enhanced Rolling Element Bearing Analysis (FEREBA), the main analysis program. A companion report addresses the input instructions for and features of the computer codes. REBANS extends the capabilities of the SHABERTH (Shaft and Bearing Thermal Analysis) code to include race and housing flexibility, including such effects as dead band and preload springs.

  8. Modeling of rolling element bearing mechanics. Computer program user's manual

    NASA Technical Reports Server (NTRS)

    Greenhill, Lyn M.; Merchant, David H.

    1994-01-01

    This report provides the user's manual for the Rolling Element Bearing Analysis System (REBANS) analysis code which determines the quasistatic response to external loads or displacement of three types of high-speed rolling element bearings: angular contact ball bearings, duplex angular contact ball bearings, and cylindrical roller bearings. The model includes the defects of bearing ring and support structure flexibility. It is comprised of two main programs: the Preprocessor for Bearing Analysis (PREBAN) which creates the input files for the main analysis program, and Flexibility Enhanced Rolling Element Bearing Analysis (FEREBA), the main analysis program. This report addresses input instructions for and features of the computer codes. A companion report addresses the theoretical basis for the computer codes. REBANS extends the capabilities of the SHABERTH (Shaft and Bearing Thermal Analysis) code to include race and housing flexibility, including such effects as dead band and preload springs.

  9. Low-energy fractures of the humeral shaft and bisphosphonate use.

    PubMed

    Yavropoulou, Maria P; Giusti, Andrea; Ramautar, Sharita R; Dijkstra, Sander; Hamdy, Neveen A T; Papapoulos, Socrates E

    2012-06-01

    Atypical fractures of the femur have been reported to occur in patients on long-term treatment with bisphosphonates; however, causality has not been proven, and it is not known whether similar fractures may occur in other long bones. We addressed this issue by examining the relationship between humeral shaft fractures and bisphosphonate use. We identified all patients aged ≥50 years consecutively admitted to a single center with a new fracture of the humerus. All individual radiographs were examined and fracture site was classified. A case-control study was undertaken in patients with humeral shaft fractures, and controls were sex- and age-matched patients with proximal humeral fractures in a 1:4 ratio. Patients with shaft fractures and radiographic characteristics similar to those of atypical femoral fractures were compared with those with ordinary shaft fractures. The association between "atypical" fractures and bisphosphonate or glucocorticoid use was examined. A total of 198 patients had a low-energy fracture of the humerus; 20 of these patients had a shaft fracture (10%). These 20 patients (cases) were matched with 80 patients with proximal fractures (controls). Bisphosphonates were used by 5% of cases and by 6.3% of controls (odds ratio [OR], 0.80; 95% confidence interval [CI], 0.09-6.85); glucocorticoids were used by 10% of cases and 8.8% of controls (OR, 1.15; 95% CI, 0.23-5.83). There was no difference in cortical thickness between cases and controls and bisphosphonate or glucocorticoid users and nonusers. Four of the 20 patients with shaft fractures had "atypical" radiographic features, with significantly increased cortical thickness, but none of these had ever been treated with bisphosphonates or glucocorticoids. Our results show that low-energy fractures of the humeral shaft with "atypical" radiographic characteristics are infrequent and are not associated with the use of bisphosphonates or glucocorticoids. Copyright © 2012 American Society for Bone

  10. Effect of Bearing Dynamic Stiffness on Gear Vibration

    NASA Technical Reports Server (NTRS)

    Fleming, David P.

    2002-01-01

    Noise is a major consideration in the design of high performance geared transmissions, such as for helicopters. Transmission error, that is, the accuracy with which the driven gear follows the driver gear, is a common indicator of noise generation. It is well known that bearing properties have a strong influence on shaft dynamics. However, up to now the contribution of bearings to transmission error has received little attention. In this paper, a torsional-axial-lateral geared rotor analysis is used to determine dynamic transmission error as a function of bearing stiffness and damping. Bearings have a similar effect as found in shaft dynamics; transmission error can be reduced more than 10 decibels by appropriate selection of bearing properties.

  11. Detailed ball bearing model for magnetic suspension auxiliary service

    NASA Astrophysics Data System (ADS)

    Sun, G.; Palazzolo, A. B.; Provenza, Andrew; Montague, Gerald

    2004-01-01

    Catcher bearings (CBs) provide backup protection for rotating machines with active magnetic bearings (AMBs). The CBs are required in the event of an AMB failure or high transient loads. Numerical simulations of a rotor drop on CBs in flywheel energy storage system are conducted with a detailed CB model which includes a Hertzian load-deflection relationship between mechanical contacts, speed-and-preload-dependent bearing stiffness due to centrifugal force, and a Palmgren's drag friction torque. The transient simulation results show the rotor shaft response variations with the design parameters: shaft/bearing friction coefficients, axial preload, support damping of damper liner, and side loads from magnetic bearings. The results reveal that friction coefficients, support damping, and side loads are critical parameters to satisfy CB design objectives and prevent backward (super) whirl.

  12. Titanium carbide modified hardfacing for use on bearing surfaces of earth boring bits

    SciTech Connect

    Sullivan, E.C.; Barnard, L.H.

    1991-08-13

    This patent describes improvement in a method of manufacturing an earth boring bit of the type having a rotatable cutter secured to a bearing shaft on a head of the bit and at least one friction bearing surface. The improvement comprises; forming a hardfacing composition by combining a particulate titanium carbide with a hard metal alloy, the particulate titanium carbide having a particle size less than about 10 micron; applying the hardfacing composition to the friction bearing surface of a selected one of the bearing shaft and rotatable cut of the earth boring bit.

  13. Stabilizing Gyroscopic Modes in Magnetic-Bearing-Supported Flywheels by Using Cross-Axis Proportional Gains

    NASA Technical Reports Server (NTRS)

    Brown, Gerald V.; Kascak, Albert F.; Jansen, Ralph H.; Dever, Timothy P.; Duffy, Kirsten P.

    2006-01-01

    For magnetic-bearing-supported high-speed rotating machines with significant gyroscopic effects, it is necessary to stabilize forward and backward tilt whirling modes. Instability or low damping of these modes can prevent the attainment of desired shaft speed. We show analytically that both modes can be stabilized by using cross-axis proportional gains and high- and low-pass filters in the magnetic bearing controller. Furthermore, at high shaft speeds, where system phase lags degrade the stability of the forward-whirl mode, a phasor advance of the control signal can partially counteract the phase lag. In some range of high shaft speed, the derivative gain for the tilt modes (essential for stability for slowly rotating shafts) can be removed entirely. We show analytically how the tilt eigenvalues depend on shaft speed and on various controller feedback parameters.

  14. Detection of cracks in shafts with the Approximated Entropy algorithm

    NASA Astrophysics Data System (ADS)

    Sampaio, Diego Luchesi; Nicoletti, Rodrigo

    2016-05-01

    The Approximate Entropy is a statistical calculus used primarily in the fields of Medicine, Biology, and Telecommunication for classifying and identifying complex signal data. In this work, an Approximate Entropy algorithm is used to detect cracks in a rotating shaft. The signals of the cracked shaft are obtained from numerical simulations of a de Laval rotor with breathing cracks modelled by the Fracture Mechanics. In this case, one analysed the vertical displacements of the rotor during run-up transients. The results show the feasibility of detecting cracks from 5% depth, irrespective of the unbalance of the rotating system and crack orientation in the shaft. The results also show that the algorithm can differentiate the occurrence of crack only, misalignment only, and crack + misalignment in the system. However, the algorithm is sensitive to intrinsic parameters p (number of data points in a sample vector) and f (fraction of the standard deviation that defines the minimum distance between two sample vectors), and good results are only obtained by appropriately choosing their values according to the sampling rate of the signal.

  15. Metal backed fixed-bearing unicondylar knee arthroplasties using minimal invasive surgery: a promising outcome analysis of 132 cases.

    PubMed

    Baur, Joel; Zwicky, Lukas; Hirschmann, Michael Tobias; Ilchmann, Thomas; Clauss, Martin

    2015-07-31

    Unicondylar knee arthroplasty (UKA) is a well-established treatment for isolated osteoarthritis (OA) of the medial knee compartment. Aim of this retrospective study was to evaluate the early clinical and radiological outcomes of a consecutive series of patients treated with medial metal backed fixed-bearing UKA. Furthermore, the influence of the component orientation on the outcome was analyzed. From 09/2006 to 11/2010 106 patients (132 knees; 69 ± 9 years) were treated using a metal backed fixed-bearing UKA with a MIS approach. All patients underwent a standardized clinical and radiological follow-up at 6 weeks, 1, 2 and 5 years. Mean follow-up was 3.4 ± 1.0 years. Two patients (three UKAs) deceased and two patients (two UKAs) were lost to follow-up. Three different survival analyses were performed using three different endpoints defining failure: (a) revision with exchange of any UKA component (b) aseptic loosening and (c), a worst case scenario, where it was assumed that all progressive radiolucencies would lead to aseptic loosening and thus these were additionally counted. Clinical outcome was assessed using the American knee society score (AKS) and the Oxford knee score (OKS). Radiographic analysis was done according to the American Knee Society Evaluation and Scoring System adapted for UKA and correlated with the AKS and OKS. Five UKAs (3.8 %) were revised to total knee arthroplasties (TKAs) after a median of 25 (10-33) months. Five year survival was 95.2, 97.5 and 87.7% for the aforementioned endpoints. At final follow-up the median AKS knee score was 99 (50-100) points and the median AKS function score was 100 (60-100) points. The median OKS was 43 (8-48) points. Clinical outcome was independent of the component orientation. Fixed-bearing UKA showed excellent clinical and radiological results at up to 5 years follow-up. Outcome was independent of component orientation.

  16. Journal bearing

    DOEpatents

    Menke, John R.; Boeker, Gilbert F.

    1976-05-11

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

  17. Dynamics of a supercritical composite shaft mounted on viscoelastic supports

    NASA Astrophysics Data System (ADS)

    Montagnier, O.; Hochard, C.

    2014-01-01

    The damping in a carbon fiber reinforced plastic (CFRP) laminate is greater than that which occurs in most metallic materials. In the supercritical regime, the damping can trigger unstable whirl oscillations, which can have catastrophic effects. The vibrations occurring in a supercritical composite drive shaft are investigated here in order to predict instabilities of this kind. A simply supported carbon/epoxy composite tube mounted on viscoelastic supports is studied, using an approximation of the Rayleigh-Timoshenko equation. The damping process is assumed to be hysteretic. The composite behavior is described in terms of modulus and loss factor, taking homogenized values. The critical speeds are obtained in several analytical forms in order to determine the effects of factors such as the rotatory inertia, the gyroscopic forces, the transverse shear and the supports stiffness. Assuming that the hysteretic damping can be expressed in terms of the equivalent viscous model, the threshold speed is obtained in the form of an analytical criterion. The influence of the various factors involved is quantified at the first critical speed of a subcritical composite shaft previously described in the literature. The influence of the coupling mechanisms on the unsymmetrical composite laminate and the end fittings is also investigated using a finite element model. None of these parameters were found to have a decisive influence in this case. Those having the greatest effects were the transverse shear and the supports stiffness. The effects of the composite stacking sequence, the shaft length and the supports stiffness on the threshold speed were then investigated. In particular, drive shafts consisting only of ±45° or ±30° plies can be said to be generally unstable in the supercritical regime due to their very high loss factors.

  18. Fluid Film Bearing Code Development

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The next generation of rocket engine turbopumps is being developed by industry through Government-directed contracts. These turbopumps will use fluid film bearings because they eliminate the life and shaft-speed limitations of rolling-element bearings, increase turbopump design flexibility, and reduce the need for turbopump overhauls and maintenance. The design of the fluid film bearings for these turbopumps, however, requires sophisticated analysis tools to model the complex physical behavior characteristic of fluid film bearings operating at high speeds with low viscosity fluids. State-of-the-art analysis and design tools are being developed at the Texas A&M University under a grant guided by the NASA Lewis Research Center. The latest version of the code, HYDROFLEXT, is a thermohydrodynamic bulk flow analysis with fluid compressibility, full inertia, and fully developed turbulence models. It can predict the static and dynamic force response of rigid and flexible pad hydrodynamic bearings and of rigid and tilting pad hydrostatic bearings. The Texas A&M code is a comprehensive analysis tool, incorporating key fluid phenomenon pertinent to bearings that operate at high speeds with low-viscosity fluids typical of those used in rocket engine turbopumps. Specifically, the energy equation was implemented into the code to enable fluid properties to vary with temperature and pressure. This is particularly important for cryogenic fluids because their properties are sensitive to temperature as well as pressure. As shown in the figure, predicted bearing mass flow rates vary significantly depending on the fluid model used. Because cryogens are semicompressible fluids and the bearing dynamic characteristics are highly sensitive to fluid compressibility, fluid compressibility effects are also modeled. The code contains fluid properties for liquid hydrogen, liquid oxygen, and liquid nitrogen as well as for water and air. Other fluids can be handled by the code provided that the

  19. Performance of a hybrid cylindrical roller bearing

    NASA Astrophysics Data System (ADS)

    Schrader, Stephen M.

    1992-08-01

    A 206-size hybrid (ceramic/steel) cylindrical roller bearing was tested in MIL-L-23699 C oil at several speeds and loads. Heat-generation data was collected and subsequently correlated with bearing-analysis software. Bearing-cage slip data was also collected at various oil-flow rates, oil temperatures, and with both MIL-L-7808 J and MIL-L-23699 C oils. The hybrid bearing was tested in MIL-L-23699 C oil for for 25 hours at 2220 N radial load and 1.08 MDN shaft speed. The hybrid bearing technology demonstrated in the report is applicable to the Integrated High Performance Turbine Engine Technology Initiative.

  20. Development of new materials for turbopump bearings

    NASA Technical Reports Server (NTRS)

    Maurer, R. E.; Pallini, R. A.

    1985-01-01

    The life requirement for the angular contact ball bearings in the Space Shuttle Main Engine (SSME) high pressure oxygen turbopump (HPOTP) is 7.5 hours. In actual operation, significantly shorter service life was experienced. The objective is to identify bearing materials and/or materials processing techniques offering signficant potential for extending HPOTP bearing performance life. Interactive thermomechanical analysis of the HPOTP bearing-shaft system was performed with the SHABERTH computer program. Bearing fatigue life, ball-race contact stress, heat generation rate, bulk ring temperatures and circumferential stress in the inner rings were quantified as functions of radial load, thrust load and ball-race contact friction. Criteria established from the output of this analysis are being used for material candidate selection.

  1. Correlation of Trochanter-Shaft Angle in Selection of Entry Site in Antegrade Intramedullary Femoral Nail

    PubMed Central

    Lakhwani, O. P.

    2012-01-01

    Background. Selection of entry point for nail insertion is controversial and lack firm anatomical basis. The study is done to analyze the proximal anthropometry of femur and measure the Trochanter-Shaft Angle to find its relation and significance in selection of entry point for antegrade uniplanar femoral nail. Materials and Methods. Study involves the measurement of trochanter-shaft angle and other anthropometric measurements on 50 dry femora and on digital radiogram. Results. Trochanter-Shaft angle ranges between 5–17 degrees in anthropometric study and 4–14 degrees in radiological study. Over all in 27 cases (54%), exit points of reamur fall in the middle quadrant in sagittal and coronal plane, which corresponds to the T-S angle of 6–12 degrees. Discussion and Conclusion. Proximal femoral Anthropometry and Trochanter-shaft angle is variable; hence it is difficult to fix any anatomical point as a universal entry point for antegrade femoral nail insertion. Trochanter shaft angle (TSA) can be well accessed radiologically and serve as a guide for selection of proper entry point.for safe nail insertion. Clinical Relevance. Individual variations in the proximal femur anatomy for safe nail insertion can be correlated with Trochanter shaft angle to serve safe entry site. PMID:24977077

  2. Successful removal of an entrapped rotablation burr by extracting drive shaft sheath followed by balloon dilatation.

    PubMed

    Sakakura, Kenichi; Ako, Junya; Momomura, Shin-ichi

    2011-10-01

    Burr entrapment is a rare but serious complication during rotational atherectomy (RA). Although emergent surgical removal is a reliable option for this complication, surgical removal is invasive and takes several hours. Balloon inflation just proximal to the burr was the previously-reported nonsurgical option for burr removal. However, this method needed large guide catheter lumen (≥8 Fr). We present a case of 67-year-old male on chronic hemodialysis. During RA for severe stenosis of the right coronary artery, the RA burr was entrapped. We cut off the drive shaft, the drive shaft sheath, and the RA wire together near the advancer, and then we removed the drive shaft sheath. After removing the drive shaft sheath, the 2.5 mm balloon easily entered the 7-Fr guide catheter. We inflated that balloon to a pressure of 18 atm. The burr was easily removed immediately after balloon deflation. Removal of the drive shaft sheath following balloon dilatation is a new, nonsurgical bailout method for a burr that becomes entrapped during RA. Since removal of the drive shaft sheath following balloon dilatation can be applied to 7 Fr as well as 6 Fr guide systems, this method may be of considerable benefit when operators use 7 Fr or 6 Fr systems.

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

    NASA Technical Reports Server (NTRS)

    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.

  4. An unusual case of hypercortisolism with multiple weight-bearing bone fractures.

    PubMed

    Papadakis, Georgios; Uebelhart, Brigitte; Goumaz, Michel; Zawadynski, Sophie; Rizzoli, Rene

    2013-09-01

    Glucocorticoid excess, either from exogenous exposure or through endogenous overproduction, is a common cause of secondary osteoporosis. We report a 52-year-old woman presenting with multiple stress fractures of the lower extremities, despite various osteoporosis therapeutic regimens. Investigations led to the diagnosis of hypercortisolism of pituitary origin. Pituitary surgery was unsuccessful, justifying a treatment of ketoconazole. In the absence of densitometric osteoporosis, assessment of bone microstructure using high resolution peripheral quantitative computed tomography revealed alterations of both the cortical and trabecular compartments. This case illustrates that hypercortisolism may cause bone fragility in the absence of marked changes in areal bone mineral density.

  5. Bone shaft bending strength index is unaffected by exercise and unloading in mice.

    PubMed

    Wallace, Ian J; Gupta, Shikha; Sankaran, Jeyantt; Demes, Brigitte; Judex, Stefan

    2015-03-01

    Anthropologists frequently use the shaft bending strength index to infer the physical activity levels of humans living in the past from their lower limb bone remains. This index is typically calculated as the ratio of bone shaft second moments of area about orthogonal principal axes (i.e. I(max)/I(min)). Individuals with high I(max)/I(min) values are inferred to have been very active, whereas individuals with low values are inferred to have been more sedentary. However, there is little direct evidence that activity has a causal and predictable effect on the shaft bending strength index. Here, we report the results of two experiments that were designed to test the model within which anthropologists commonly interpret the shaft bending strength index. In the first experiment, mice were treated daily with treadmill exercise for 1 month to simulate a high-activity lifestyle. In the second experiment, in an attempt to simulate a low-activity lifestyle, functional weight-bearing was removed from the hindlimbs of mice for 1 month. Femoral mid-shaft structure was determined with μCT. We found that while exercise resulted in significant enhancement of I(max) and I(min) compared with controls, it failed to significantly increase the I(max)/I(min)index. Similarly, stunted bone growth caused by unloading resulted in significantly diminished I(max) and I(min) compared with controls, but low activity did not lead to significantly decreased I(max)/I(min)compared with normal activity. Together, these results suggest that caution is required when the bone shaft bending strength index is used to reconstruct the activity levels of past humans.

  6. Bone shaft bending strength index is unaffected by exercise and unloading in mice

    PubMed Central

    Wallace, Ian J; Gupta, Shikha; Sankaran, Jeyantt; Demes, Brigitte; Judex, Stefan

    2015-01-01

    Anthropologists frequently use the shaft bending strength index to infer the physical activity levels of humans living in the past from their lower limb bone remains. This index is typically calculated as the ratio of bone shaft second moments of area about orthogonal principal axes (i.e. Imax/Imin). Individuals with high Imax/Imin values are inferred to have been very active, whereas individuals with low values are inferred to have been more sedentary. However, there is little direct evidence that activity has a causal and predictable effect on the shaft bending strength index. Here, we report the results of two experiments that were designed to test the model within which anthropologists commonly interpret the shaft bending strength index. In the first experiment, mice were treated daily with treadmill exercise for 1 month to simulate a high-activity lifestyle. In the second experiment, in an attempt to simulate a low-activity lifestyle, functional weight-bearing was removed from the hindlimbs of mice for 1 month. Femoral mid-shaft structure was determined with μCT. We found that while exercise resulted in significant enhancement of Imax and Imin compared with controls, it failed to significantly increase the Imax/Imin index. Similarly, stunted bone growth caused by unloading resulted in significantly diminished Imax and Imin compared with controls, but low activity did not lead to significantly decreased Imax/Imin compared with normal activity. Together, these results suggest that caution is required when the bone shaft bending strength index is used to reconstruct the activity levels of past humans. PMID:25645569

  7. Proximal hypospadias with skin-covered shaft of penis and absent urethral plate: An unknown variant and its management

    PubMed Central

    Rashid, Kumar A.; Bhat, Nisar A.

    2011-01-01

    We report a case of proximal hypospadias with an absent urethral plate having intact ventral shaft skin with hooded dorsal prepuce and a good glans groove. Such a variant of hypospadias has not been reported in the literature. PMID:22121320

  8. Constant-mesh, multiple-shaft transmission

    SciTech Connect

    Rea, J.E.; Mills, D.D.; Sewell, J.S.

    1992-04-21

    This patent describes a multiple-shaft, constant-mesh transmission adapted to establish selectively a reverse torque delivery path and a forward drive torque delivery path and having a torque input means including a torque input shaft, a mainshaft aligned with the input shaft, a countershaft geared to the input shaft in spaced, parallel relationship with respect to the mainshaft, a torque output shaft joined to the mainshaft; multiple mainshaft gear elements journalled on the main airshaft, multiple cluster gear elements carried by the countershaft in meshing engagement with the mainshaft gear elements, one of the cluster gear elements being rotatably journalled on the countershaft; a reverse idle gear, a reverse gear journalled on the countershaft, the reverse idler gear being in constant mesh with the reverse gear and one of the mainshaft gear elements; first clutch means for connecting selectively the reverse gear and the countershaft; second synchronizer clutch means for connecting selectively the one of the mainshaft gear elements to the mainshaft; and third synchronizer clutch means for selectively connecting another of the mainshaft gear elements to the mainshaft; the first clutch means being a double-acting clutch with a first common axially movable clutch element adapted upon movement in one axial direction to drivably connected the reverse gear to the countershaft and adapted upon movement in the opposite axial direction to connect the one cluster gear element to the countershaft.

  9. Instability of asymmetric continuous shaft system

    NASA Astrophysics Data System (ADS)

    Srinath, R.; Sarkar, Abhijit; Sekhar, A. S.

    2016-11-01

    In this work, the governing equation of asymmetric continuous shaft in inertial frame of reference is studied. In particular, determination of the parameter ranges for the stability or instability of the shaft response is the focus of the present work. The governing equations are a fourth-order coupled partial differential equations containing time dependent coefficients. The equations are non-dimensionalized in terms of two parameters related to the average moment of inertia and the difference of moments of inertia about the principal axes. Using the latter as the asymptotic parameter and employing modal superposition, a formal methodology based on perturbation methods is developed to ascertain the stability and instability characteristics. The methodology is applicable to shafts subjected to some of the classical boundary conditions viz. simply supported, cantilever, and fixed-fixed. Similar stability curves are obtained for each mode for these different boundary conditions. The novel non-dimensionalization scheme chosen leads to the stability boundaries as well as the loci of varying speeds to be in the form of straight lines. The intersection of these lines determine the stable and unstable speed ranges of different asymmetric shafts. The results are generalized for different material and geometric properties of the shaft.

  10. CENTRIFUGAL PUMP AND SHAFT SEALING MEANS

    DOEpatents

    Rushing, F.C.

    1960-09-01

    A description is given of sealing means between a hollow rotatable shaft and a stationary member surrounding the shaft which defines therewith a sealing space of annular cross-section, comprising a plurality of axially spaced rings held against seats by ring springs which serve to subdivide the sealing space- into a plurality of zones. Process gas introduced into the hollow shaft through a port communicating with a centrally located zone which iu turn communicates with a bore in the sleeve, is removed from the shaft through a second port communicating with an adjacent central zone and discharged through a second bore. A sealant gas is supplied to an end zone under a pressure sufficient to cause it to flow axially into adjacent zones and then maintained at a lower pressure than either the sealant gas source or the process gas inlet zone, preventing the sealant gas from entering the shaft and allowing gases leaking into the sealant gas to be withdrawn and led to a separator.

  11. High Pressure Rotary Shaft Sealing Mechanism

    DOEpatents

    Dietle, Lannie; Gobeli, Jeffrey D.

    2001-05-08

    A laterally translatable pressure staged rotary shaft sealing mechanism having a seal housing with a shaft passage therein being exposed to a fluid pressure P1 and with a rotary shaft being located within the shaft passage. At least one annular laterally translatable seal carrier is provided. First and second annular resilient sealing elements are supported in axially spaced relation by the annular seal carriers and have sealing relation with the rotary shaft. The seal housing and at least one seal carrier define a first pressure staging chamber exposed to the first annular resilient sealing element and a second pressure staging chamber located between and exposed to the first and second annular resilient sealing elements. A first fluid is circulated to the first pressure chamber at a pressure P1, and a second staging pressure fluid is circulated to the second pressure chamber at a fraction of pressure P1 to achieve pressure staging, cooling of the seals. Seal placement provides hydraulic force balancing of the annular seal carriers.

  12. A “clearcut” case? Brown bear selection of coarse woody debris and carpenter ants on clearcuts

    PubMed Central

    Frank, Shane C.; Steyaert, Sam M.J.G.; Swenson, Jon E.; Storch, Ilse; Kindberg, Jonas; Barck, Hanna; Zedrosser, Andreas

    2015-01-01

    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

  13. Combination radial and thrust magnetic bearing

    NASA Technical Reports Server (NTRS)

    Blumenstock, Kenneth A. (Inventor)

    2002-01-01

    A combination radial and thrust magnetic bearing is disclosed that allows for both radial and thrust axes control of an associated shaft. The combination radial and thrust magnetic bearing comprises a rotor and a stator. The rotor comprises a shaft, and first and second rotor pairs each having respective rotor elements. The stator comprises first and second stator elements and a magnet-sensor disk. In one embodiment, each stator element has a plurality of split-poles and a corresponding plurality of radial force coils and, in another embodiment, each stator element does not require thrust force coils, and radial force coils are replaced by double the plurality of coils serving as an outer member of each split-pole half.

  14. Adaptive automatic balancing of magnetic bearing systems

    NASA Astrophysics Data System (ADS)

    Kim, Jong-Sun

    Rotating machinery including magnetic bearings are usually persistently excited by the rotation related disturbances such as mass unbalance; hence there exists a residual vibration in the steady state response even if the closed loop system is asymptotically stable. In order to control the periodic disturbances, a disturbance accommodating controller (DAC) is designed based on the disturbance estimator and applied to the forced balancing of magnetic bearing system. The control objective is to minimize the synchronous component of shaft displacement or control current. In order to account for the variation of the disturbance model due to the shaft of operating speed, an adaptive disturbance accommodating control scheme is developed based on a certain optimality criterion. The continuous time design discretized to implement the controller in the digital computer and the merits and demerits are studied numerically. It is shown that the proposed method is efficient in reducing rotor unbalance and automatic balancing.

  15. Case report: Pseudotumor associated with corrosion of a femoral component with a modular neck and a ceramic-on-polyethylene bearing.

    PubMed

    Messana, Joe; Adelani, Muyibat; Goodman, Stuart B

    2014-01-01

    Pseudotumor is a rare complication that can occur following hip arthroplasty. This complication may present with pain, swelling, and decreased function and may lead to bone and soft-tissue destruction. We report a case of pseudotumor formation resulting from corrosion of a modular neck in a hip replacement with a ceramic-on-polyethylene bearing. The patient underwent successful revision surgery using an extended trochanteric osteotomy, removal of the entire stem, and implantation of a new femoral stem and ceramic-polyethylene bearing without a modular neck.

  16. How NOT to Dispose of NORM/TENORM-bearing Wastes: A Case Study

    SciTech Connect

    Karam, P. A.

    2002-02-26

    The Ashtabula River in northern Ohio contains a large amount of sediment containing quantities of NORM and TENORM from previous industrial activities at nearby mineral processing plants. Due to PCB contamination, these sediments were to be dredged and isolated in a landfill to be constructed by the responsible parties. Unfortunately, the State of Ohio has determined that these wastes may not be disposed of in this manner, and this determination has resulted in delaying the remediation project. Computer models performed using the RESRAD computer code indicate that isolating these wastes in this manner will reduce dose to the nearby population because the NORM/TENORM will be safely buried beneath a compacted clay cover and isolated from all sources of exposure. In fact, radiation doses (including radon emanation) from these wastes in a properly maintained landfill are significantly lower than in the present condition, and the reduction is even more marked for NORM/TENORM in tailings piles. This suggests that, in many cases, disposal of NORM/TENORM wastes in on-site landfills may be a cost-effective and dose-conscious method of disposal, if regulatory issues can be resolved.

  17. Independent wheel suspension system using constant velocity universal joints in combination with a single prop shaft joint and mounted differentials

    SciTech Connect

    Krude, W.

    1986-06-24

    An independent wheel suspension system is described for a vehicle having a chassis, vehicle support means for resiliently supporting the chassis for displacement with respect to a driving surface, a wheel assembly with a wheel rotatable about a wheel axis, and an engine adapted to provide driving torque about an engine output axis at an engine output, the independent wheel suspension system consists of: control arm means having a wheel end pivotably connected to the wheel assembly and a pair of frame ends pivotably connected to a respective pair of pivot bearings carried by the vehicle support means to define a swing axis therethrough; differential means comprising a differential housing, differential input means and differential output means within the differential housing establishing a respective differential input axis and a differential output axis substantially perpendicular thereto; transverse pivot means coupling the differential means and the vehicle support means for allowing the differential means to pivot relative to the vehicle support means about a transverse pivot axis substantially parallel to the differential output axis; and prop shaft means having a prop shaft axis and first and second prop shaft coupling means coupling, respectively, to the engine output and the differential input, the first prop shaft coupling means being a constant velocity universal joint, the second prop shaft coupling means being one of an axially splined joint or a fixed joint; whereby, as the first prop shaft coupling means undergoes articulation with respect to the prop shaft means as the chassis undergoes the displacement, the transverse pivot means allows the differential means to pivot relative to the vehicle support means about the transverse pivot axis to accommodate the articulation without articulation between the differential means and the prop shaft means.

  18. Grizzly bear

    USGS Publications Warehouse

    Schwartz, C.C.; Miller, S.D.; Haroldson, M.A.; Feldhamer, G.; Thompson, B.; Chapman, J.

    2003-01-01

    The grizzly bear inspires fear, awe, and respect in humans to a degree unmatched by any other North American wild mammal. Like other bear species, it can inflict serious injury and death on humans and sometimes does. Unlike the polar bear (Ursus maritimus) of the sparsely inhabited northern arctic, however, grizzly bears still live in areas visited by crowds of people, where presence of the grizzly remains physically real and emotionally dominant. A hike in the wilderness that includes grizzly bears is different from a stroll in a forest from which grizzly bears have been purged; nighttime conversations around the campfire and dreams in the tent reflect the presence of the great bear. Contributing to the aura of the grizzly bear is the mixture of myth and reality about its ferocity. unpredictable disposition, large size, strength, huge canines, long claws, keen senses, swiftness, and playfulness. They share characteristics with humans such as generalist life history strategies. extended periods of maternal care, and omnivorous diets. These factors capture the human imagination in ways distinct from other North American mammals. Precontact Native American legends reflected the same fascination with the grizzly bear as modern stories and legends (Rockwell 1991).

  19. Rotating flexible disk under shaft temperature increment

    NASA Astrophysics Data System (ADS)

    Pei, Yong-Chen; He, Ling; Wang, Ji-Xin

    2010-08-01

    A rotating flexible annular thin disk subjected to the temperature increment of the shaft clamping the disk was modeled in this paper. At disk top and bottom surfaces and free outer edge, the heat convection boundaries were assumed. Disk transverse deflection was considered as a function of both disk radial and circumferential coordinates, and temperature distribution was solved along disk thickness and radial directions simultaneously. As a result, the shaft temperature increment causes thermo-elastic instability of some disk modes. Effects of the shaft temperature increment, ratio of disk convective heat transfer coefficient to thermal conductivity, disk thickness, nodal circle and diameter numbers of disk mode on the natural frequencies, thermo-elastic instability and critical angular speed of the disk were discussed.

  20. Superconducting Meissner Effect Bearings for Cryogenic Turbomachines

    DTIC Science & Technology

    1991-02-27

    bearing zone and the cold expansion turbine. Small diameter turbine shafts are overhung as far as possible while still retaining adequately high...has been fabricated and tested - a simple rotor disk-superconductor configuration to demonstrate rotational and surface speed prototypical of...miniature turbomachines can be stably and repeatably achieved. The simple disk rotor configuration is shown schematically in Figure 1. A cylindrical

  1. Cryogenic anti-friction bearing with reinforced inner race

    NASA Technical Reports Server (NTRS)

    Blount, Dale H. (Inventor)

    1991-01-01

    This invention consists of a bearing (26) designed to operate in a cryogenic environment and which has an inner raceway (30) generally constructed as an annular band fitted by an interference fit to a rotating shaft (12). A pair of annular tension bands (32, 34) are fitted onto opposed sides of the band and function to firmly clamp the raceway (30) to the shaft (12). This occurs because the tension bands are constructed of a material which, when cooled to aproximately -385.degree. F., shrinks more than the raceway (30) and the shaft (12) to which it is fitted. The bands further relax somewhat at room temperature and permit the interference fit between the raceway (30) and the shaft (12) to be sized such that the raceway (30) is not overly stessed.

  2. Cryogenic anti-friction bearing with inner race

    NASA Technical Reports Server (NTRS)

    Blount, Dale H. (Inventor)

    1990-01-01

    This invention consists of a bearing designed to operate in a cryogenic environment and which has an inner raceway generally constructed as an annular band fitted by an interference fit to a rotating shaft. A pair of annular tension bands are fitted onto opposed sides of the band and function to firmly clamp the raceway to the shaft. This occurs because the tension bands are constructed of a material which, when cooled to approximately -335 F shrinks more than the raceway and the shaft to which it is fitted. The bands further relax somewhat at room temperature and permit the interference fit between the raceway and the shaft to be sized such that the raceway is not overly stressed.

  3. Bearing fatigue investigation 3

    NASA Technical Reports Server (NTRS)

    Nahm, A. H.; Bamberger, E. N.; Signer, H. R.

    1982-01-01

    The operating characteristics of large diameter rolling-element bearings in the ultra high speed regimes expected in advanced turbine engines for high performance aircraft were investigated. A high temperature lubricant, DuPont Krytox 143 AC, was evaluated at bearing speeds to 3 million DN. Compared to the results of earlier, similar tests using a MIL-L-23699 (Type II) lubricant, bearings lubricated with the high density Krytox fluid showed significantly higher power requirements. Additionally, short bearing lives were observed when this fluid was used with AISI M50 bearings in an air atmosphere. The primary mode of failure was corrosion initiated surface distress (fatigue) on the raceways. The potential of a case-carburized bearing to sustain a combination of high-tangential and hertzian stresses without experiencing race fracture was also investigated. Limited full scale bearing tests of a 120 mm bore ball bearing at a speed of 25,000 rpm (3 million DN) indicated that a carburized material could sustain spalling fatigue without subsequent propagation to fracture. Planned life tests of the carburized material had to be aborted, however, because of apparent processing-induced material defects.

  4. Experimental investigation of the flow in a simplified model of water lubricated axial thrust bearing

    NASA Astrophysics Data System (ADS)

    Kirschner, O.; Ruprecht, A.; Riedelbauch, S.

    2014-03-01

    In hydropower plants the axial thrust bearing takes up the hydraulic axial thrust of the runner and, in case of vertical shafts, the entire weight of all rotating masses. The use of water lubricated bearings can eliminate the oil leakage risk possibly contaminating the environment. A complex flow is generated by the smaller film thickness due to the lower viscosity of water compared with oil. Measurements on a simplified hydrostatic axial trust bearing model were accomplished for validating CFD analysis of water lubricated bearings. In this simplified model, fixed pads are implemented and the width of the gap was enlarged to create a higher resolution in space for the measurements. Most parts of the model were manufactured from acrylic glass to get optical access for measurement with PIV. The focus of these measurements is on the flow within the space between two pads. Additional to the PIV- measurement, the pressure on the wall of the rotating disk is captured by pressure transducers. The model bearing measurement results are presented for varied operating conditions.

  5. Are the Oxford(®) medial unicompartmental knee arthroplasty new instruments reducing the bearing dislocation risk while improving components relationships? A case control study.

    PubMed

    Koh, I J; Kim, J H; Jang, S W; Kim, M S; Kim, C; In, Y

    2016-04-01

    The recently introduced Microplasty(®) system is an upgrade of conventional phase III instrumentation. However, little is known of its impact on the position of the implant following the Oxford(®) mobile-bearing unicompartmental knee arthroplasty (UKA). This study investigated whether the Microplasty(®) instrumentation system can improve the positioning of the implant and reduce the rate of early failure. Microplasty(®) provides a better positioning and decreases the rate of dislocation. The medical records and radiographs of 82 consecutive Oxford(®) UKAs were reviewed retrospectively. The radiographic parameters and prevalence of early failure of 41 UKAs performed with the Microplasty(®) system and 41 UKAs using the conventional instrumentation system were compared. Both groups were comparable in terms of demographics and preoperative status. The femoral components in the Microplasty(®) group were more contiguously placed and more convergent in relation to the tibial components compared to the conventional instrumentation system (P<0.01). The frequency of bearing dislocation was lower in the Microplasty(®) group (P=0.04). A wide gap and the angle between components were associated with an increased risk of bearing dislocation. The Microplasty(®) instrumentation system consistently placed the femoral and tibial components in more contiguous and convergent positions. Such changes in position decreased the risk of bearing dislocations by reducing the space available for bearing rotation. Level III, case control study. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  6. Component analysis report: Line shaft pump bushings, Warm Springs State Hospital, Warm Springs, Montana

    SciTech Connect

    McAlpin, Ron

    1981-03-01

    On 29 January 1981, the Failure Analysis Laboratory at Radian Corporation received two spider bushings from the State Hospital at Warm Springs, Montana, for metallurgical analysis. The bushings are from a 19 stage, 200 hp Worthington line shaft vertical turbine pump. The pump was set at 830 feet to test a low temperature geothermal well. One bushing was originally set near the top of the well; the other bushing had been set deep in the well. The bushings were reportedly manufactured from bronze sleeve-bearing material. After approximately 50 hours of intermittent operation, the pump began to experience severe vibration. The vibration appeared random in that it sometimes occurred immediately upon start up and other times occurred after several hours of operation. A Worthington service engineer tested the pump and made several recommendations to alleviate the problem. He concluded that excessive packing box friction, overloading, and shaft unscrewing caused the vibration. He also adjusted the vertical shaft and impeller clearances. The purposes of this analysis is to examine the shaft bushings for evidence of mechanical or corrosion damage that might have been related to the vibration problem.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    Addy, Harold E., Jr.; Schuller, Frederick 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 10000 to 24000 RPM. Thrust loads were varied from 4450 to 17800 Newtons (1000 to 4000 lbs.). Radial loads were varied from 1335 to 13350 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.

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

    NASA Astrophysics Data System (ADS)

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

    1993-06-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    1993-06-01

    A parametric experimental investigation of an 85 millimeter bore angular contact ball bearing running in RP-1 fuel was performed at speeds of 10000 to 24000 RPM. Thrust loads were varied from 4450 to 17800 Newtons (1000 to 4000 lbs.). Radial loads were varied from 1335 to 13350 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.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    SciTech Connect

    Addy, H.E. Jr.; Schuller, F.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. 10 refs.

  13. Variables affecting the manifestation of and intensity of pacing behavior: A preliminary case study in zoo-housed polar bears.

    PubMed

    Cless, Isabelle T; Lukas, Kristen E

    2017-09-01

    High-speed video analysis was used to quantify two aspects of gait in 10 zoo-housed polar bears. These two variables were then examined as to how they differed in the conditions of pacing versus locomoting for each bear. Percent difference calculations measured the difference between pacing and locomoting data for each bear. We inferred that the higher the percent difference between pacing and locomoting in a given subject, the more intense the pacing may be. The percent difference values were analyzed alongside caregiver survey data defining the locations, frequency, and anticipatory nature of pacing in each bear, as well as each bear's age and sex, to determine whether any variables were correlated. The frequency and intensity of pacing behavior were not correlated. However, location of pacing was significantly correlated both with the subjects' age and whether or not the subject was classified as an anticipatory pacer. Bears appeared to select specific spots within their exhibits to pace, and the location therefore seemed tied to underlying motivation for the behavior. Additionally, bears that were classified in the survey as pacing anticipatorily displayed significantly more intense pacing behavior as quantified by gait analysis. © 2017 Wiley Periodicals, Inc.

  14. The case for ceramic-on-polyethylene as the preferred bearing for a young adult hip replacement.

    PubMed

    Cash, David J W; Khanduja, Vikas

    2014-01-01

    The optimum choice of bearing surfaces in total hip arthroplasty, particularly in the younger and more active patient, remains controversial. Despite several studies demonstrating good long-term results for the metal-on-polyethylene articulation, there has been a recent vogue towards the utilisation of hard-on-hard bearings for younger patients due, in part, to concerns regarding polyethylene induced osteolysis. However, well-documented complications concerning metal-on-metal bearings and the risk of fracture in ceramic-on-ceramic bearings have raised concerns regarding the principle of the hard-on-hard bearing in the active patient. With recent technological advancements in the manufacture of both polyethylene and alumina ceramics, the in vitro properties of each material with regards to strength and toughness have been significantly improved. In addition, ceramic femoral heads have consistently been shown to produce less in vivo polyethylene wear than similar sized metal heads. This paper aims to critically review the biomechanical, in vivo and clinical studies related to the use of the ceramic on polyethylene bearing, and highlights its potential use as the preferred bearing for a young adult hip replacement.

  15. Polar Bears

    USGS Publications Warehouse

    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).

  16. Polar Bear

    USGS Publications Warehouse

    Amstrup, S.D.; ,; Lentfer, J.W.

    1988-01-01

    Polar bears are long-lived, late-maturing carnivores that have relatively low rates of reproduction and natural mortality. Their populations are susceptible to disturbance from human activities, such as the exploration and development of mineral resources or hunting. Polar bear populations have been an important renewable resource available to coastal communities throughout the Arctic for thousands of years.

  17. Cooling system for a bearing of a turbine rotor

    DOEpatents

    Schmidt, Mark Christopher

    2002-01-01

    In a gas turbine, a bore tube assembly radially inwardly of an aft bearing conveys cooling steam to the buckets of the turbine and returns the cooling steam to a return. To cool the bearing and thermally insulate the bearing from the cooling steam paths, a radiation shield is spaced from the bore tube assembly by a dead air gap. Additionally, an air passageway is provided between the radiation shield and the inner surface of an aft shaft forming part of the rotor. Air is supplied from an inlet for flow along the passage and radially outwardly through bores in the aft shaft disk to cool the bearing and insulate it from transfer of heat from the cooling steam.

  18. Spherical bearing. [to reduce vibration effects

    NASA Technical Reports Server (NTRS)

    Myers, W. N.; Hein, L. A. (Inventor)

    1978-01-01

    A spherical bearing including an inner ball with an opening for receiving a shaft and a spherical outer surface is described. Features of the bearing include: (1) a circular outer race including a plurality of circumferentially spaced sections extending around the inner ball for snugly receiving the inner ball; and (2) a groove extending circumferentially around the race producing a thin wall portion which permits the opposed side portions to flex relative to the ball for maximizing the physical contact between the inner surface of the race and the spherical outer surface of the ball.

  19. Automobile transmission with output shaft parallel to crank shaft and parking gear fixed to the output shaft

    SciTech Connect

    Kubo, S.; Kuramochi, K.; Kyushima, T.

    1987-06-30

    A driving device is described for an automobile having axles, driving wheels supported by the axles and an engine located proximate the driving wheels, having a crankshaft disposed substantially parallel to the axles supporting the driving wheels, the device comprising: a fluid-type torque converter having coaxial input and output members and disposed on one axial side of the engine connected to and coaxial with the crankshaft; an auxiliary speed change gear assembly having coaxial input and output members and disposed on one axial side of the torque converter remote from the engine with the input member connected to and coaxial of the torque converter; the output member of the auxiliary speed change gear assembly is provided in the shape of a gear; a transmission shaft disposed substantially parallel to the auxiliary speed change gear assembly; a driven gear having a disc portion and toothed peripheral portion; a drive gear drivingly connected to the other end of the transmission shaft closer to the torque converter than the one end of the transmission shaft; a final reduction gear disposed between the driving wheels to be in meshing engagement with the drive gear to transmit power to the axles; a parking gear comprising an annular gear element fixed by bolts proximate the toothed peripheral portion to the axial side surface from which the transmission shaft extends toward the other end. The parking gear is supported by the disc portion for rotation with the driven gear; and means for selectively engaging the parking gear to prevent rotation of shaft when automobile is in parking condition.

  20. Nonisthmal femoral shaft nonunion as a risk factor for exchange nailing failure.

    PubMed

    Yang, Kyu Hyun; Kim, Jung Ryul; Park, Jin

    2012-02-01

    Although nail exchange with a larger diameter nail after additional reaming is typically considered the gold standard for failed femoral nailing, some reports question the role of exchange nailing. The purpose of this study was to evaluate the risk factors affecting the outcome of exchange nailing for femoral shaft nonunion after initial nailing. Forty-one consecutive patients treated with exchange nailing between November 1996 and March 2010 for femoral shaft nonunion that was initially managed with an intramedullary nailing were retrospectively reviewed. Possible risk factors and outcome (bony union) of exchange nailing were evaluated. Of the 41 femoral shaft nonunions treated with exchange nailing, 9 (22%) failed to achieve bony union. The union rate for isthmal nonunions was 87% (27 of 31 cases) and for nonisthmal nonunions was 50% (5 of 10 cases). Univariate and multivariate logistic regression analyses demonstrated that the anatomic site (isthmal vs. nonisthmal) was a significant risk factor for exchange nailing failure (univariate, p = 0.021; multivariate, p = 0.016). Although exchange nailing is an excellent choice for aseptic isthmal femoral shaft nonunion occurring after the initial nailing, other treatment options such as augmentative plating should be considered for nonisthmal femoral shaft nonunions.

  1. Computer Simulation Usage For Verification Of Deepened Shaft Artificial Bottom Construction

    NASA Astrophysics Data System (ADS)

    Gospodarczyk, Piotr

    2015-12-01

    The paper presents the design verification methodology for so called artificial bottom of the mining shaft using computer simulation. Artificial bottom serves as the protection of the lower part of the shaft, in which works related to shaft deepening are carried out, against falling to the bottom of the shaft elements transported in its upper, active part. Model describing the phenomenon of artificial bottom stress is complex. In presented case it is a process of collision between object with a mass of 18 Mg model, falling into the shaft from a height of 800 m, and artificial bottom construction and inducted phenomenon of stress and strain wave propagation in various elements of construction. In this case load receiving elements are heavily deformed and many of them has to be destroyed. Therefore for construction verification computer simulation method has been chosen, conducted on the basis of subsequent crash tests, using the LS-DYNA program. The object of the research was an innovative solution of artificial bottom, developed by Central Mining Institute. A series of falling mass impact tests were performed, which had to prove the usefulness of applied solutions, as well as determine the influence of selected construction geometric parameters to effectiveness of transferring the impact load. This way, using the successive approximations method, the assumptions about the number of artificial bottom platforms and plate thickness used for additional coverage of one of the platforms were verified.

  2. Study on vibration characteristics of the shaft system for a dredging pump based on FEM

    NASA Astrophysics Data System (ADS)

    Zhai, L. M.; Qin, L.; Liu, C. Y.; Liu, X.; He, L. Y.; He, Y.; Wang, Z. W.

    2012-11-01

    The dynamic characteristics of the shaft system for a dredging pump were studied with the Finite Element Method (FEM) by SAMCEF ROTOR. At first, the influence of the fluid-solid coupling interaction of mud water and impeller, water sealing and pump shaft on the lateral critical speeds were analyzed. The results indicated that the mud water must be taken into consideration, while the water sealing need not to. Then the effects of radial and thrust rolling bearings on the lateral critical speeds were discussed, which shows that the radial bearing close to the impeller has greatest impact on the 1st order critical speed. At last, the upper and lower limits of the critical speeds of lateral, axial and torsional vibration were calculated. The rated speed of the dredging pump was far less than the predicted critical speed, which can ensure the safe operation of the unit. Each vibration mode is also shown in this paper. This dynamic analysis method offers some reference value on the research of vibration and stability of the shaft system in dredging pump.

  3. 17. TRACTOR ENGINE POWERING SHAFT SYSTEM IN FOREGROUND, BELT CONNECTS ...

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

    17. TRACTOR ENGINE POWERING SHAFT SYSTEM IN FOREGROUND, BELT CONNECTS WITH MAIN SHAFT LOOKING EAST. - W. A. Young & Sons Foundry & Machine Shop, On Water Street along Monongahela River, Rices Landing, Greene County, PA

  4. 8. IRON MOUNTAIN SHAFT ROOM TO UNIT #5 SHOWING TYPICAL ...

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

    8. IRON MOUNTAIN SHAFT ROOM TO UNIT #5 SHOWING TYPICAL ARRANGEMENT OF SHAFT AND PUMP IN COLORADO RIVER AQUEDUCT PUMPHOUSES. - Iron Mountain Pump Plant, South of Danby Lake, north of Routes 62 & 177 junction, Rice, San Bernardino County, CA

  5. 6. VIEW OF DRIFT SHAFT, HOIST MOTOR, WORM WHEEL GEAR ...

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

    6. VIEW OF DRIFT SHAFT, HOIST MOTOR, WORM WHEEL GEAR ASSEMBLY, CROSS SHAFT, AND INTERMEDIATE GEAR HOIST ASSEMBLY FOR CONTROL GATE NO. 6, LOOKING WEST - Long Lake Hydroelectric Plant, Spillway Dam, Spanning Spokane River, Ford, Stevens County, WA

  6. 161. BLACKSMITH SHOP, OVERHEAD SHAFT. BELT ON LEFT CONNECTS TO ...

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

    161. BLACKSMITH SHOP, OVERHEAD SHAFT. BELT ON LEFT CONNECTS TO SHAFTS WHICH RUN POWER PRESS AND HYDRAULIC TIRE SETTER. - Gruber Wagon Works, Pennsylvania Route 183 & State Hill Road at Red Bridge Park, Bernville, Berks County, PA

  7. Tilting pad gas bearing design for micro gas turbines

    NASA Astrophysics Data System (ADS)

    Nabuurs, M. J. H. W.; Al-Bender, F.; Reynaerts, D.

    2013-12-01

    This paper presents the results of a dynamic stability investigation of a micro gas turbine supported by two flexible tilting pad bearings. The pad flexibility allows centrifugal and thermal shaft growth of the rotor but can also introduce undesirable rotor instabilities. An eigenvalue analysis on the linearised rotor-bearing dynamics is performed to estimate the required pad stiffness and damping for stability. Results of the eigenvalue analysis are evaluated by fully nonlinear orbit simulations.

  8. Factors that affect the fatigue strength of power transmission shafting

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.

    1984-01-01

    A long standing objective in the design of power transmission shafting is to eliminate excess shaft material without compromising operational reliability. A shaft design method is presented which accounts for variable amplitude loading histories and their influence on limited life designs. The effects of combined bending and torsional loading are considered along with a number of application factors known to influence the fatigue strength of shafting materials. Among the factors examined are surface condition, size, stress concentration, residual stress and corrosion fatigue.

  9. Comparison of residual stresses in sand- and chill casting of ductile cast iron wind turbine main shafts

    NASA Astrophysics Data System (ADS)

    Sonne, M. R.; Frandsen, J. O.; Hattel, J. H.

    2015-06-01

    In this work, simulations of pouring, solidification and cooling, and residual stress evolution of sand and chill cast wind turbine main shafts is performed. The models are made in the commercial software MAGMAsoft. As expected, the cooling rate of the sand casting is shown to be much lower than for the chill casting, resulting in a very course microstructure. From the simulations the nodule count is found to be 17 nodules per mm2 and 159 nodules per mm2 for the sand and chill casting, respectively, in the critical region of the main bearing seat. This is verified from nodule counts performed on the real cast main shafts. Residual stress evaluations show an overall increase of the maximum principal stress field for the chill casting, which is expected. However, the stresses are found to be in compression on the surface of the chill cast main shaft, which is unforeseen.

  10. Interference Fit Life Factors for Roller Bearings

    NASA Technical Reports Server (NTRS)

    Oswald, Fred B.; Zaretsky, Erwin V.; Poplawski, Joseph V.

    2008-01-01

    The effect of hoop stresses in reducing cylindrical roller bearing fatigue life was determined for various classes of inner ring interference fit. Calculations were performed for up to seven interference fit classes for each of ten bearing sizes. Each fit was taken at tightest, average and loosest values within the fit class for RBEC-5 tolerance, thus requiring 486 separate analyses. The hoop stresses were superimposed on the Hertzian principal stresses created by the applied radial load to calculate roller bearing fatigue life. The method was developed through a series of equations to calculate the life reduction for cylindrical roller bearings based on interference fit. All calculated lives are for zero initial bearing internal clearance. Any reduction in bearing clearance due to interference fit was compensated by increasing the initial (unmounted) clearance. Results are presented as tables and charts of life factors for bearings with light, moderate and heavy loads and interference fits ranging from extremely light to extremely heavy and for bearing accuracy class RBEC 5 (ISO class 5). Interference fits on the inner bearing ring of a cylindrical roller bearing can significantly reduce bearing fatigue life. In general, life factors are smaller (lower life) for bearings running under light load where the unfactored life is highest. The various bearing series within a particular bore size had almost identical interference fit life factors for a particular fit. The tightest fit at the high end of the RBEC-5 tolerance band defined in ANSI/ABMA shaft fit tables produces a life factor of approximately 0.40 for an inner-race maximum Hertz stress of 1200 MPa (175 ksi) and a life factor of 0.60 for an inner-race maximum Hertz stress of 2200 MPa (320 ksi). Interference fits also impact the maximum Hertz stress-life relation.

  11. 30 CFR 56.19130 - Conveyance shaft test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Conveyance shaft test. 56.19130 Section 56... Inspection and Maintenance § 56.19130 Conveyance shaft test. Before hoisting persons and to assure that the... round trip after: (a) Any hoist or shaft repairs or related equipment repairs that might restrict...

  12. Influence of Rocket Engine Characteristics on Shaft Sealing Technology Needs

    NASA Technical Reports Server (NTRS)

    Keba, John E.

    1999-01-01

    This paper presents viewgraphs of The Influence of Rocket Engine Characteristics on Shaft Sealing Technology Needs. The topics include: 1) Rocket Turbomachinery Shaft Seals (Inter-Propellant-Seal (IPS) Systems, Lift-off Seal Systems, and Technology Development Needs); 2) Rocket Engine Characteristics (Engine cycles, propellants, missions, etc., Influence on shaft sealing requirements); and 3) Conclusions.

  13. 30 CFR 57.19130 - Conveyance shaft test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Conveyance shaft test. 57.19130 Section 57... Hoisting Inspection and Maintenance § 57.19130 Conveyance shaft test. Before hoisting persons and to assure... least one round trip after— (a) Any hoist or shaft repairs or related equipment repairs that...

  14. 30 CFR 57.4261 - Shaft-station waterlines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shaft-station waterlines. 57.4261 Section 57... and Control Firefighting Equipment § 57.4261 Shaft-station waterlines. Waterline outlets that are located at underground shaft stations and are part of the mine's fire protection system shall have...

  15. 30 CFR 57.19135 - Rollers in inclined shafts.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Rollers in inclined shafts. 57.19135 Section 57... Hoisting Inspection and Maintenance § 57.19135 Rollers in inclined shafts. Rollers used in operating inclined shafts shall be lubricated, properly aligned, and kept in good repair....

  16. 14 CFR 27.931 - Shafting critical speed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Shafting critical speed. 27.931 Section 27... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.931 Shafting critical speed. (a) The critical speeds of any shafting must be determined by demonstration except...

  17. 14 CFR 29.931 - Shafting critical speed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Shafting critical speed. 29.931 Section 29... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.931 Shafting critical speed. (a) The critical speeds of any shafting must be determined by demonstration except...

  18. Analysis of foil bearings for high speed operation in cryogenic applications

    NASA Technical Reports Server (NTRS)

    Carpino, Marc

    1991-01-01

    The general objective of this project is to develop analysis tools which are required for the design of foil bearings to be used in cryogenic applications. During the second year of this project, a general analysis approach and code for journal bearings operating under steady state conditions will be completed. This will be followed by the initiation of an investigation into transient behavior of foil bearings to determine their performance in rotor systems. Foil bearings have been proposed as an alternative to rolling element bearings for use in cryogenic turbopumps in liquid propellant rocket engines. This type of bearing offers several advantages over rolling element bearings since they would use the cryogenic pump fluid for a lubricant and have structural flexibility. These bearings have the potential of high reliability and long life. The bearing surface is constructed of a 'foil' which resists deflection by a combination of bending, membrane, and elastic foundation effects. The relative motion between the rotating shaft and the foil causes pressure in the fluid film to develop. This pressure deflects the the foil surface away from the shaft. Once a full fluid film is established between the foil and the rotor shaft, contact no longer takes place and there is no subsequent wear of the surfaces. The flexible foil structure of the bearing allows it to compensate for minor tolerance and manufacturing defects. This same flexibility also has a significant effect on the dynamic performance of the rotor-bearing system.

  19. Magnetic Bearing

    NASA Technical Reports Server (NTRS)

    1996-01-01

    AVCON, Inc. produces advanced magnetic bearing systems for industrial use, offering a unique technological approach based on contract work done at Marshall Space Flight Center and Lewis Research Center. Designed for the turbopump of the Space Shuttle main engine, they are now used in applications such as electric power generation, petroleum refining, machine tool operation and natural gas pipelines. Magnetic bearings support moving machinery without physical contact; AVCON's homopolar approach is a hybrid of permanent and electromagnets which are one-third the weight, smaller and more power- efficient than previous magnetic bearings.

  20. Good bearings reduce downtime

    SciTech Connect

    Kinney, J.; Foster, J.

    1982-12-01

    Points out that a poorly maintained $100 bearing can hold up the operation of a $1-million conveyor. Of all the moving parts in a coal conveyor system, few cost less or last longer than anti-friction bearings. Most modern conveyor systems are equipped with 2 types of bearings: troughing idlers, spaced at regular intervals to support the conveyor belt as it travels throughout the system, and the adaptermounted spherical roller bearing pillow blocks that are used in the head, tail, bend and takeup pulleys that drive, alter the direction of, or regulate tension in the belt to allow for repairs or splicing. Explains how pillow blocks should handle radial or axial loads, how to mount bearings correctly, and how rings prevent infiltration. Concludes that by making certain that the proper bearing types are built into the system initially, or used as replacements in case of failures, paying close attention to installation procedures and devoting adequate time to maintenance, conveyor system bearings can provide decades of problem-free service.

  1. Radiolucent lines in low-contact-stress mobile-bearing total knee arthroplasty: a blinded and matched case control study

    PubMed Central

    2011-01-01

    Background Low-contact-stress (LCS) mobile-bearing total knee arthroplasty (TKA) (Johnson & Johnson, New Brunswick, NJ; previously: DePuy, Warsawa, USA) provides excellent functional results and wear rates in long-term follow-up analyses. Radiological analysis shows radiolucent lines (RLL) appearing immediately or two years after primary implantation, indicative of poor seat. Investigations proved RLL to be more frequent in uncemented TKA, resulting in a consensus to cement the tibial plateau, but their association with clinical findings and patients discomfort and knee pain is still unknown. Methods 553 patients with 566 low-contact-stress (LCS) total knee prostheses were screened for continuous moderate knee pain. We compared tibial stress shielding classified by Ewald in patients suffering from pain with a matched, pain-free control group on blinded X-rays. We hypothesized a positive correlation between pain and radiolucency and higher frequency of such radiolucent lines in the most medial and most lateral zones of the tibial plateau. Results Twenty-eight patients suffered from knee pain in total. Radiolucencies were detected in 27 of these cases and in six out of 28 matched controls without knee pain. We could demonstrate a significant correlation of knee pain and radiolucencies, which appeared significantly more frequently in the outermost zones of the tibial plateau. Conclusion Our findings suggest that radiolucent lines, representing poor implant seat, about the tibial plateau are associated with knee pain in LCS patients. Radiolucencies are observed more often in noncemented LCS, and cementing the tibial plateau might improve implant seat and reduce both radiolucent lines and associated knee pain. PMID:21714916

  2. MSFC cryogenic turbopump bearing tester results and analysis

    NASA Technical Reports Server (NTRS)

    Dolan, F. J.; Cody, J. C.

    1986-01-01

    A full scale High Pressure Oxidizer Turbopump (HPOTP) bearing tester has been developed, and an existing test stand modified, to simulate turbopump operating conditions for Space Shuttle Main Engine HPOTP design. Following a description of test facilities and procedures, design certification and calibration tests, and tests at a moderate axial load, are discussed. Results show that a bearing life of about 4500 seconds is comparable to the life experienced in the engine pump at nominal high power level operating conditions, and that although increased coolant flow increased fluid viscous work and bearing loads, a net decrease in bearing temperature was noted. Increased coolant flow is found to improve bearing cooling for marginal conditions, and bearing temperatures are shown to become more sensitive to coolant flow as shaft speed is increased. For the 6.4 lbs/s test conditions, the heat generated in a bearing pair is determined to be about 67 percent viscous work and 33 percent contact friction.

  3. Femoral shaft osteotomy for obligate outward rotation due to SCFE.

    PubMed

    Stevens, Peter M; Anderson, Lucas; MacWilliams, Bruce A

    2017-04-01

    Slipped capital femoral epiphysis (SCFE) is an adolescent disease that leads to retroversion of the femoral neck and shaft, relative to the head. Observing that patients with SCFE must walk with an outward foot progression angle and externally rotate the leg in order to flex the hip, we have been performing a femoral shaft rotational osteotomy wherein we rotate the lower femur 45° inward, relative to the upper femur. By correcting retroversion, our goal is to improve functional hip and knee motion, thereby mitigating the effects of SCFE impingement. This is a retrospective review of five hips in four patients (two boys and two girls), average age 14.7 years (range 11 + 7-18 years) who underwent femoral midshaft rotational osteotomy for correction of acquired retroversion of the femur secondary to severe SCFE. We compared clinical findings at the outset to those at an average follow-up of 46 months (range 24-74 months). Pre- and post-gait analysis was performed in three patients. Two of the patients underwent elective arthroscopic osteochondroplasty to alleviate residual FAI: contralateral arthroscopy is pending in one. The first patient in this series received a hip arthroplasty, 62 months after his osteotomy, at age 23. Following midshaft osteotomy, all patients experienced improvement in comfort, gait and activities of daily living. With the patella neutral, they had improved range of hip flexion from an average preoperative flexion of <25° to a postoperative flexion of >90°. Two patients (both male) had delayed union and some loss of correction, secondary to broken interlocking screws; each healed with reamed, exchange nailing. The interlocking screws have since been redesigned and enlarged. Femoral shaft rotational osteotomy restores the functional range of hip motion, while correcting obligate out-toeing and improving knee kinematics. This procedure is technically straightforward, permitting progressive weight bearing, while avoiding the risk of AVN

  4. Structural vibration and acoustic radiation of coupled propeller-shafting and submarine hull system due to propeller forces

    NASA Astrophysics Data System (ADS)

    Qu, Yegao; Su, Jinpeng; Hua, Hongxing; Meng, Guang

    2017-08-01

    This paper investigates the structural and acoustic responses of a coupled propeller-shafting and submarine pressure hull system under different propeller force excitations. The entire system, which consists of a rigid propeller, a main shaft, two bearings and an orthogonally stiffened pressure hull, is submerged in a heavy fluid. The shaft is elastically connected to the pressure hull by a radial bearing and a thrust bearing. The theoretical model of the structural system is formulated based on a modified variational method, in which the propeller, the main shaft and the bearings are treated as a lumped mass, an elastic beam and spatially distributed spring-damper systems, respectively. The rings and stringers in the pressure hull are modeled as discrete structural elements. The acoustic field generated by the hull is calculated using a spectral Kirchhoff-Helmholtz integral formulation. A strongly coupled structure-acoustic interaction analysis is employed to achieve reasonable solutions for the coupled system. The displacement of the pressure hull and the sound pressure of the fluid are expanded in the form of a double mixed series using Fourier series and Chebyshev orthogonal polynomials, providing a flexible way for the present method to account for the individual contributions of circumferential wave modes to the vibration and acoustic responses of the pressure hull in an analytical manner. The contributions of different circumferential wave modes of the pressure hull to the structural and acoustic responses of the coupled system under axial, transversal and vertical propeller forces are investigated. Computed results are compared with those solutions obtained from the coupled finite element/boundary element method. Effects of the ring and the bearing stiffness on the acoustic responses of the coupled system are discussed.

  5. Design and development of a high-speed bearing test rig

    NASA Technical Reports Server (NTRS)

    Cockburn, J. A.

    1995-01-01

    The development of a high-speed test rig, to be used for compiling an experimental data base of bearing signatures for bearings with known faults, is described. This bearing test rig can be adapted to test oil-film bearings as well as rolling element bearings. This is achieved by mounting the test bearing in one of two special test housings, either of which can be mounted onto a common test shaft which can be driven up to 30,000 rpm. The test bearing housing for rolling element bearings can accommodate proximity displacement transducers, accelerometers, thermocouples, and acoustic emission sensors. The test bearing housing for the fluid-film bearings can accommodate the same instrumentation as well as Bourdon tube-type transducers for measuring oil film pressures around the bearing circumference.

  6. An externally pressurized air bearing system, journals and thrust, for application to small turbomachinery

    NASA Astrophysics Data System (ADS)

    Turner, A. B.; Davies, S. J.; Nimir, Y. L.; Richardson, J. D.

    1992-06-01

    Experiments have been conducted to examine the feasibility of externally pressurized air bearings for possible utilization in small high-speed turbomachinery such as compressor and turbine test rigs. The bearing was designed employing a simplified theory that proved to be adequate, with the problem of thermal expansion solved using brass bearings sleeved with graphited bronze, up to a shaft/bearing temperature of 180 C. A new thrust bearing was demonstrated with a potential capacity greatly in excess of the conventional aerostatic, close contact, parallel disk type of thrust bearing.

  7. Foil bearings

    NASA Astrophysics Data System (ADS)

    Elrod, David A.

    1993-11-01

    The rolling element bearings (REB's) which support many turbomachinery rotors offer high load capacity, low power requirements, and durability. Two disadvantages of REB's are: (1) rolling or sliding contact within the bearing has life-limiting consequences; and (2) REB's provide essentially no damping. The REB's in the Space Shuttle Main Engine (SSME) turbopumps must sustain high static and dynamic loads, at high speeds, with a cryogenic fluid as lubricant and coolant. The pump end ball bearings limit the life of the SSME high pressure oxygen turbopump (HPOTP). Compliant foil bearing (CFB) manufacturers have proposed replacing turbopump REB's with CFB's CFB's work well in aircraft air cycle machines, auxiliary power units, and refrigeration compressors. In a CFB, the rotor only contracts the foil support structure during start up and shut down. CFB damping is higher than REB damping. However, the load capacity of the CFB is low, compared to a REB. Furthermore, little stiffness and damping data exists for the CFB. A rotordynamic analysis for turbomachinery critical speeds and stability requires the input of bearing stiffness and damping coefficients. The two basic types of CFB are the tension-dominated bearing and the bending-dominated bearing. Many investigators have analyzed and measured characteristics of tension-dominated foil bearings, which are applied principally in magnetic tape recording. The bending-dominated CFB is used more in rotating machinery. This report describes the first phase of a structural analysis of a bending-dominated, multileaf CFB. A brief discussion of CFB literature is followed by a description and results of the present analysis.

  8. Foil bearings

    NASA Technical Reports Server (NTRS)

    Elrod, David A.

    1993-01-01

    The rolling element bearings (REB's) which support many turbomachinery rotors offer high load capacity, low power requirements, and durability. Two disadvantages of REB's are: (1) rolling or sliding contact within the bearing has life-limiting consequences; and (2) REB's provide essentially no damping. The REB's in the Space Shuttle Main Engine (SSME) turbopumps must sustain high static and dynamic loads, at high speeds, with a cryogenic fluid as lubricant and coolant. The pump end ball bearings limit the life of the SSME high pressure oxygen turbopump (HPOTP). Compliant foil bearing (CFB) manufacturers have proposed replacing turbopump REB's with CFB's CFB's work well in aircraft air cycle machines, auxiliary power units, and refrigeration compressors. In a CFB, the rotor only contracts the foil support structure during start up and shut down. CFB damping is higher than REB damping. However, the load capacity of the CFB is low, compared to a REB. Furthermore, little stiffness and damping data exists for the CFB. A rotordynamic analysis for turbomachinery critical speeds and stability requires the input of bearing stiffness and damping coefficients. The two basic types of CFB are the tension-dominated bearing and the bending-dominated bearing. Many investigators have analyzed and measured characteristics of tension-dominated foil bearings, which are applied principally in magnetic tape recording. The bending-dominated CFB is used more in rotating machinery. This report describes the first phase of a structural analysis of a bending-dominated, multileaf CFB. A brief discussion of CFB literature is followed by a description and results of the present analysis.

  9. Correlations of the instantaneous carrying force and pressure distribution in the case of the narrow sliding radial bearing under hard shocks

    NASA Astrophysics Data System (ADS)

    Alexandrescu, I. M.; Coteţiu, R.; Darabă, D.

    2017-02-01

    We present the determining relationship of carriage in non-dimensional form for narrow radial bearings subjected to shocks and vibrations, as well as the determining relationships of the lubricant minimum thickness in relation to the dynamic loading. Due to the very short time of loading radial bearings subjected to shocks and vibrations, of about 0.5-1 ms, we consider only the approaching motion between spindle/axle and bushing on the direction of the centre line, without the rotation of the spindle/axle (the case of the non-rotating bearing), so that the effect of the lubricant expulsion be prevalent in the achieving of the self-carrying film. The paper is focused on determining relationship of carriage in dimensional form for narrow radial bearings exposed to shocks and vibrations, as well as the determining relationships of the pressure distribution from the film to be lubricated in various places of the bearing’s body. It is showed the details during the measuring accomplishments and the experimental results are registered in a record of obtained results. This paper was accepted for publication in Proceedings after double peer reviewing process but was not presented at the Conference ROTRIB’16

  10. Tachometer Derived From Brushless Shaft-Angle Resolver

    NASA Technical Reports Server (NTRS)

    Howard, David E.; Smith, Dennis A.

    1995-01-01

    Tachometer circuit operates in conjunction with brushless shaft-angle resolver. By performing sequence of straightforward mathematical operations on resolver signals and utilizing simple trigonometric identity, generates voltage proportional to rate of rotation of shaft. One advantage is use of brushless shaft-angle resolver as main source of rate signal: no brushes to wear out, no brush noise, and brushless resolvers have proven robustness. No switching of signals to generate noise. Another advantage, shaft-angle resolver used as shaft-angle sensor, tachometer input obtained without adding another sensor. Present circuit reduces overall size, weight, and cost of tachometer.

  11. Tachometer Derived From Brushless Shaft-Angle Resolver

    NASA Technical Reports Server (NTRS)

    Howard, David E.; Smith, Dennis A.

    1995-01-01

    Tachometer circuit operates in conjunction with brushless shaft-angle resolver. By performing sequence of straightforward mathematical operations on resolver signals and utilizing simple trigonometric identity, generates voltage proportional to rate of rotation of shaft. One advantage is use of brushless shaft-angle resolver as main source of rate signal: no brushes to wear out, no brush noise, and brushless resolvers have proven robustness. No switching of signals to generate noise. Another advantage, shaft-angle resolver used as shaft-angle sensor, tachometer input obtained without adding another sensor. Present circuit reduces overall size, weight, and cost of tachometer.

  12. Multiple giant angiokeratoma of Fordyce on the shaft of the penis masquerading as keratoacanthoma*

    PubMed Central

    Ghosh, Sudip Kumar; Ghosh, Shouvik; Agarwal, Megha

    2015-01-01

    The term 'angiokeratoma' includes a wide range of dermatological conditions of hyperkeratotic vascular disorders with a similar histologic combination of hyperkeratosis and superficial dermal vascular ectasia. Angiokeratomas can be classified into localized and systemic forms. Angiokeratoma of Fordyce (AKF) is a localized form of angiokeratoma, clinically characterized by 1- to 6-mm, black, blue, or dark red, dome-shaped papules located on the scrotum, shaft of penis, labia majora, clitoris, inner thigh, and lower abdomen. We describe herein a case of giant angiokeratoma of Fordyce on shaft of the penis in an elderly man, clinically masquerading as keratoacanthoma. PMID:26312700

  13. Research into the impact of shafts misalignment of turbocompressor installation on power characteristics of a drive engine

    NASA Astrophysics Data System (ADS)

    Kipervasser, M. V.; Gerasimuk, A. V.

    2016-10-01

    In the present paper the emergency situation in operation of a turbocompressor installation is considered, which leads to shafts misalignment, connected by rigid couplings, of the drive synchronous electric motor and multiplicator is considered. Misalignment of shafts causes vibrations in the course of work of a turbine unit that, in its turn, can result in untimely wear of bearings, loosening of different fasteners and breakdown of the whole installation. The analysis of shafts misalignment of electric motor and planetary gearbox (multiplicator) regarding the emergence of mechanical power surge and derivation of corresponding equations is performed. The mathematical modelling of a turbine unit operation taking into account misalignment in MatLAB Simulink is carried out. The graphs of mechanical power surges on the shaft of the electric motor and current surges in the phase of its stator are received. The conclusion about the possibility of recording stator current surges by standard measurement methods and use of this fact for development of a current protection against misalignment of shafts is made.

  14. Humeral Shaft Fracture Treatment in the Elite Throwing Athlete: A Unique Application of Flexible Intramedullary Nailing

    PubMed Central

    Lee, Christopher S.; Davis, Shane M.; Fronek, Jan

    2013-01-01

    Humeral shaft stress fractures are being increasingly recognized as injuries that can significantly impact throwing mechanics if residual malalignment exists. While minimally displaced and angulated injuries are treated nonoperatively in a fracture brace, the management of significantly displaced humeral shaft fractures in the throwing athlete is less clear. Currently described techniques such as open reduction and internal fixation with plate osteosynthesis and rigid antegrade/retrograde locked intramedullary nailing have significant morbidity due to soft tissue dissection and damage. We present a case report of a high-level baseball pitcher whose significantly displaced humeral shaft stress fracture failed to be nonoperatively managed and was subsequently treated successfully with unlocked, retrograde flexible intramedullary nailing. The athlete was able to return to pitching baseball in one year and is currently pitching in Major League Baseball. We were able to recently collect 10-year follow-up data. PMID:24369515

  15. Humeral shaft fracture treatment in the elite throwing athlete: a unique application of flexible intramedullary nailing.

    PubMed

    Lee, Christopher S; Davis, Shane M; Ho, Hoang-Anh; Fronek, Jan

    2013-01-01

    Humeral shaft stress fractures are being increasingly recognized as injuries that can significantly impact throwing mechanics if residual malalignment exists. While minimally displaced and angulated injuries are treated nonoperatively in a fracture brace, the management of significantly displaced humeral shaft fractures in the throwing athlete is less clear. Currently described techniques such as open reduction and internal fixation with plate osteosynthesis and rigid antegrade/retrograde locked intramedullary nailing have significant morbidity due to soft tissue dissection and damage. We present a case report of a high-level baseball pitcher whose significantly displaced humeral shaft stress fracture failed to be nonoperatively managed and was subsequently treated successfully with unlocked, retrograde flexible intramedullary nailing. The athlete was able to return to pitching baseball in one year and is currently pitching in Major League Baseball. We were able to recently collect 10-year follow-up data.

  16. Safety of the shaft-wheel assembly of electric locomotives

    NASA Astrophysics Data System (ADS)

    Todic, M.; Golubovic-Bugarski, V.

    2017-05-01

    Shafts of electric locomotives are exposed to complex normal and tangential stresses during its exploitation. These stresses could have extremely high level producing the breakage of the shaft. It is well known that shafts have much longer service life than wheels. However, since the stresses in shaft’s material are high, it is possible to micro-cracks appear and propagate until the shaft’s breakage. The breakage of the shaft may cause the great human and material losses. Because of that, during manufacturing these assemblies it must be taken into account all parameters which can initiate shaft crack. Geometric measure of seating and shaft are recommended by UIC regulations having great influence to quality and safety of realized assembly. The influence of contact surfaces and their lubrication during manufacturing the shaft - wheel assembly is shown in this paper.

  17. Hemi-arthroplasty of the hip followed by ipsilateral fracture of the femoral shaft.

    PubMed

    Barfod, G; Steen Jensen, J; Hansen, D; Larsen, E; Menck, H; Olsen, B; Rosenklint, A

    1986-03-01

    In a series of 74 ipsilateral fractures of the femoral shaft in relation to hemi-arthroplasties, treatment by a cemented long-stem total hip replacement was found to be superior to conservative treatment or internal fixation without removal of the prosthesis. Acceptable clinical results were obtained in 89 per cent of these cases.

  18. Seismic bearing

    NASA Astrophysics Data System (ADS)

    Power, Dennis

    2009-05-01

    Textron Systems (Textron) has been using geophones for target detection for many years. This sensing capability was utilized for detection and classification purposes only. Recently Textron has been evaluating multiaxis geophones to calculate bearings and track targets more specifically personnel. This capability will not only aid the system in locating personnel in bearing space or cartesian space but also enhance detection and reduce false alarms. Textron has been involved in the testing and evaluation of several sensors at multiple sites. One of the challenges of calculating seismic bearing is an adequate signal to noise ratio. The sensor signal to noise ratio is a function of sensor coupling to the ground, seismic propagation and range to target. The goals of testing at multiple sites are to gain a good understanding of the maximum and minimum ranges for bearing and detection and to exploit that information to tailor sensor system emplacement to achieve desired performance. Test sites include 10A Site Devens, MA, McKenna Airfield Ft. Benning, GA and Yuma Proving Ground Yuma, AZ. Geophone sensors evaluated include a 28 Hz triax spike, a 15 Hz triax spike and a hybrid triax spike consisting of a 10 Hz vertical geophone and two 28 Hz horizontal geophones. The algorithm uses raw seismic data to calculate the bearings. All evaluated sensors have triaxial geophone configuration mounted to a spike housing/fixture. The suite of sensors also compares various types of geophones to evaluate benefits in lower bandwidth. The data products of these tests include raw geophone signals, seismic features, seismic bearings, seismic detection and GPS position truth data. The analyses produce Probability of Detection vs range, bearing accuracy vs range, and seismic feature level vs range. These analysis products are compared across test sites and sensor types.

  19. Lunar vertical-shaft mining system

    NASA Technical Reports Server (NTRS)

    Introne, Steven D. (Editor); Krause, Roy; Williams, Erik; Baskette, Keith; Martich, Frederick; Weaver, Brad; Meve, Jeff; Alexander, Kyle; Dailey, Ron; White, Matt

    1994-01-01

    This report proposes a method that will allow lunar vertical-shaft mining. Lunar mining allows the exploitation of mineral resources imbedded within the surface. The proposed lunar vertical-shaft mining system is comprised of five subsystems: structure, materials handling, drilling, mining, and planning. The structure provides support for the exploration and mining equipment in the lunar environment. The materials handling subsystem moves mined material outside the structure and mining and drilling equipment inside the structure. The drilling process bores into the surface for the purpose of collecting soil samples, inserting transducer probes, or locating ore deposits. Once the ore deposits are discovered and pinpointed, mining operations bring the ore to the surface. The final subsystem is planning, which involves the construction of the mining structure.

  20. Treatment shaft for combined sewer overflow detention.

    PubMed

    Wright, Steven J; Ghalib, Saad; Eloubaidy, Aziz

    2010-05-01

    A deep, large-diameter underground shaft to provide detention storage for combined sewer overflow control may be advantageous in urban environments, where space limitations require solutions with a small footprint. An underflow baffle wall is provided at the center of the treatment shaft to prevent short-circuiting of the flow. An additional objective is to maintain low headlosses through the structure. A physical model study was conducted to determine the effect of the bottom elevation of the baffle wall on the headloss and breakthrough curve for dye injected to the inflow. It was found that there is a considerable range of elevations for which the structure behaves acceptably in providing adequate contact time for disinfectant while maintaining small headlosses.