WorldWideScience
 
 
1

THRUST BEARING  

Science.gov (United States)

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.

Heller, P.R.

1958-09-16

2

Lateral dampers for thrust bearings. Final Report  

Energy Technology Data Exchange (ETDEWEB)

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

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

1985-08-01

3

Thermal effects in an accelerating thrust bearing  

Energy Technology Data Exchange (ETDEWEB)

This study is mainly concerned with the development of transient temperatures in a thrust bearing. The effect of Prandtl number on temperatures was also investigated. All lubricant properties were assumed to be constant. It was found that the location of highest temperatures depended on the bearing ratio. The effect of Prandtl number on temperatures was small. However, its effect on the heat transfer at the surfaces was significant. 6 references.

Doo, R.; Rodkiewicz, C.M.; Gupta, R.N.

1985-05-01

4

Well drilling tool with diamond radial/thrust bearings  

Energy Technology Data Exchange (ETDEWEB)

A turbodrill is disclosed for connection to a drill string and has a rotating shaft for turning a drill bit. The turbodrill has rotor and stator blades operated by drilling mud flowing therethrough to rotate the shaft. The shaft is provided with radial/thrust bearing consisting of a pair of annular plates, each of which has conical surfaces supporting a plurality of friction bearing members of polycrystalline diamond. The radial and thrust loads are carried by the wear-resistant diamond bearing surfaces. The bearing members are preferably cylindrical studs having flat faces with flat disc-shaped diamond bearing members supported thereon around the adjacent surfaces of the supporting plates. The faces of the diamond bearings will wear into smoothly mating conical bearing surfaces with use. There are two or more pairs of diamond radial/thrust bearings to handle longitudinal as well as radial loads. The use of the diamond radial/thrust bearings makes it possible to eliminate the lubricant-flooded construction of prior art turbodrills and allow the bearings to be cooled and lubricated be drilling fluid flowing therethrough. The diamond radial/thrust bearings may be used with lubricant-flooded turbodrills and with other types of downhole motor driven drills such as drills driven by positive displacement motors.

Nagel, D.D.; Aparicio, T. Jr.

1983-10-18

5

Frictional Characteristics of Thrust Bearing in Scroll Compressor  

Science.gov (United States)

This paper presents frictional characteristics of thrust bearing in scroll compressor focusing on the behavior of sliding portion which affects the generation of oil film. The coefficient of friction and tilt angle of sliding portion in the thrust bearing are obtained through both elemental friction test and cylinder pressure measurement of actual scroll compressor. Both tests showed that the coefficient of friction in low contact pressure rose with increase of tilt angle of sliding portion. The value of contact pressure which the coefficient of friction turns into increase was in agreement of the value which tilt angle become to increase. Numerical analysis using mixed lubrication theory was also performed. Analytical result indicated the same characteristics as the experiments, and the correlation between the coefficient of friction and the behavior of sliding portion was confirmed. Based on the experimental and the analytical results obtained here, the optimization of thrust bearing for commercial scroll compressor was applied. 2% improvement of total efficiency in rated condition was archived by optimization of thrust bearing.

Sato, Hajime; Itoh, Takahide; Kobayashi, Hiroyuki

6

Rotary Microactuator Supported on Encapsulated Microball Bearings using an Electro-Pneumatic Thrust Balance.  

Science.gov (United States)

The development of a rotary microactuator supported on encapsulated microball bearings and driven by electro-pneumatic actuation is reported. The encapsulated bearing provides full support to an encased rotor, while an electro-pneumatic thrust balance is ...

C. M. Waits M. McCarthy M. I. Beyaz R. Ghodssi

2009-01-01

7

Ontario Hydro`s Sir Adam Beck Pump Generating Station : thrust bearing and runner servomotor rehabilitation  

Energy Technology Data Exchange (ETDEWEB)

A study was conducted to examine the reasons for the recurring failure of generator thrust bearings at Ontario Hydro`s Sir Adam Beck Pump Generating Station (Niagara Falls) comprised of six 25 MW Deriaz turbines. The possible causes for the thrust bearing failures were listed and commented upon. The suspected causes include: (1) marginal bearing capacity, (2) shoes not flat, (3) sub standard oil, (4) dirt in bearing, (5) bearing cooling problems. To solve the problem, extra precaution was taken in the assembly of the bearing parts and extra capacity was added to the oil lift system. Following implementation of these measures, the unit has been operating smoothly for 3 years. 3 tabs., 4 figs.

Barbour, J.; Garro, A. [Ontario Hydro, Toronto, ON (Canada)

1998-12-01

8

Analysis of a Thrust Bearing with Flexible Pads and Flexible Supports  

DEFF Research Database (Denmark)

A theoretical analysis of a hydrodynamic thrust bearing is presented. The bearing investigated is used in an ndustrial product. The lubricant is water, but the results are valid also for other lubricants.At first the results from a 1-dimensional model for the fluid film forces and the associated deformation of the bearing geometry is presented. This model enlightens the influence of pad flexibility and support location and flexibility. Subsequently results from a 2-dimensional model of the bearing is presented. The model is used to carry out an optimization of the bearing design, and the obtained improvements in load carrying capacity is presented.

Klit, Peder; Thomsen, Kim

2007-01-01

9

Little Long G.S. - analysis and repairs to resolve a series of thrust bearing failures  

Energy Technology Data Exchange (ETDEWEB)

A Westinghouse Double Row Kingsbury Thrust Bearing at Unit 1 of Ontario Hydro`s Little Long Generation Station on the Mattagami River has recently experienced a series of four failures within a period of 16 months. The cause of each failure appears to have been different, ranging from bearing overload to thermal ratchetting. Each failure was investigated, followed by a series of measures taken to put the units back in service. Measures taken after each failure have been detailed. The investigation into the failures and analysis of the bearing wipes suggests that the oil cooling was the cause of the last two bearing failures. It was also determined that a loose thrust block/outer runner plate coupling bolt phenomenon was not the contributing factor in the last three bearing failures. The unit was still dismantled at the time of this report but was scheduled for a return to service in April 1998. 1 ref., 24 figs.

Armstrong, O.L.; Greig, J.M. [Ontario Hydro, Toronto, ON (Canada)

1998-12-01

10

A rotary microactuator supported on encapsulated microball bearings using an electro-pneumatic thrust balance  

Science.gov (United States)

The development of a rotary microactuator supported on encapsulated microball bearings and driven by electro-pneumatic actuation is reported. The encapsulated bearing provides full support to an encased rotor, while an electro-pneumatic thrust balance is used to minimize rotor normal load. By minimizing normal load, bearing friction is reduced leading to increased speed and performance. Experimental results show that the microactuator is capable of repeatable operation and continuous 360° motion at speeds of 5-2000 rpm. This is the first demonstration of a ball bearing supported electrostatic microactuator with a fully encased rotor, capable of direct mechanical attachment or reliable interaction with external media.

McCarthy, Matthew; Waits, C. Mike; Beyaz, Mustafa I.; Ghodssi, Reza

2009-09-01

11

Optimization of residual heat removal pump axial thrust and axial bearing  

International Nuclear Information System (INIS)

The residual heat removal (RHR) pumps of German 1300 megawatt pressurized-water reactor (PWR) power plants are of the single stage end suction type with volute casing or with diffuser and forged circular casing. Due to the service conditions the pumps have to cover the full capacity range as well as a big variation in suction static pressure. This results in a big difference in the axial thrust that has to be borne by the axial bearing. Because these pumps are designed to operate without auxiliary systems (things that do not exist can not fail), they are equipped with antifriction bearings and sump oil lubrication. To minimize the heat production within the bearing casing, a number of PWR plants have pumps with combined axial/radial bearings of the ball type. Due to the fact that the maximum axial thrust caused by static pressure and hydrodynamic forces on the impeller is too big to be borne by that type of axial bearing, the impellers were designed to produce a hydrodynamic axial force that counteracts the static axial force. Thus, the resulting axial thrust may change direction when the static pressure varies

1996-01-01

12

Optimization of residual heat removal pump axial thrust and axial bearing  

Energy Technology Data Exchange (ETDEWEB)

The residual heat removal (RHR) pumps of German 1300 megawatt pressurized-water reactor (PWR) power plants are of the single stage end suction type with volute casing or with diffuser and forged circular casing. Due to the service conditions the pumps have to cover the full capacity range as well as a big variation in suction static pressure. This results in a big difference in the axial thrust that has to be borne by the axial bearing. Because these pumps are designed to operate without auxiliary systems (things that do not exist can not fail), they are equipped with antifriction bearings and sump oil lubrication. To minimize the heat production within the bearing casing, a number of PWR plants have pumps with combined axial/radial bearings of the ball type. Due to the fact that the maximum axial thrust caused by static pressure and hydrodynamic forces on the impeller is too big to be borne by that type of axial bearing, the impellers were designed to produce a hydrodynamic axial force that counteracts the static axial force. Thus, the resulting axial thrust may change direction when the static pressure varies.

Schubert, F.

1996-12-01

13

Fault architecture and deformation mechanisms in exhumed analogues of seismogenic carbonate-bearing thrusts  

Science.gov (United States)

Faults in carbonates are well known sources of upper crustal seismicity throughout the world. In the outer sector of the Northern Apennines, ancient carbonate-bearing thrusts are exposed at the surface and represent analogues of structures generating seismicity at depth. We describe the geometry, internal structure and deformation mechanisms of three large-displacement thrusts from the km scale to the microscale. Fault architecture and deformation mechanisms are all influenced by the lithology of faulted rocks. Where thrusts cut across bedded or marly limestones, fault zones are thick (tens of metres) and display foliated rocks (S-CC? tectonites and/or YPR cataclasites) characterized by intense pressure-solution deformation. In massive limestones, faulting occurs in localized, narrow zones that exhibit abundant brittle deformation. A general model for a heterogeneous, carbonate-bearing thrust is proposed and discussed. Fault structure, affected by stratigraphic heterogeneity and inherited structures, influences the location of geometrical asperities and fault strain rates. The presence of clay minerals and the strain rate experienced by fault rocks modulate the shifting from cataclasis-dominated towards pressure-solution-dominated deformation. Resulting structural heterogeneity of these faults may mirror their mechanical and seismic behaviour: we suggest that seismic asperities are located at the boundaries of massive limestones in narrow zones of localized slip whereas weak shear zones constitute slowly slipping portions of the fault, reflecting other types of "aseismic" behaviour.

Tesei, Telemaco; Collettini, Cristiano; Viti, Cecilia; Barchi, Massimiliano R.

2013-10-01

14

A low-friction high-load thrust bearing and the human hip joint  

Energy Technology Data Exchange (ETDEWEB)

A hydrostatic thrust bearing operating at a pressure of 130 MPa and with a coefficient of friction rising to 0.004 in 6 days is described. It consists of interleaved oil-coated Mylar and brass sheets, each 0.1 mm thick. At this pressure, the Mylar deforms to reveal a pool of lubricant bounded by contacting layers at its edges where the pressure tapers off to zero. Thus, most of the load is borne by the oil so its effective Coulomb (slip-stick) friction is very low. Expressions for the effective coefficient of friction, the area of the solid-to-solid contact and the torque needed to rotate the bearing are given in terms of its geometry, the viscosity of the lubricant and elapsed time. The mechanism of a bearing with similar geometry and properties, the human hip joint, is compared with this plastic bearing. While their low friction properties arise from the same basic cause, the different natures of their soft deformable materials lead to the hip joint having a much wider range of action. This work is an example of new engineering leading to a fresh insight into an action of Nature, which in turn suggests an improvement in engineering.

McIlraith, A H, E-mail: a.h.mci@xtra.co.n [Physics and Engineering Laboratory, Lower Hutt (New Zealand)

2010-06-15

15

A low-friction high-load thrust bearing and the human hip joint  

International Nuclear Information System (INIS)

A hydrostatic thrust bearing operating at a pressure of 130 MPa and with a coefficient of friction rising to 0.004 in 6 days is described. It consists of interleaved oil-coated Mylar and brass sheets, each 0.1 mm thick. At this pressure, the Mylar deforms to reveal a pool of lubricant bounded by contacting layers at its edges where the pressure tapers off to zero. Thus, most of the load is borne by the oil so its effective Coulomb (slip-stick) friction is very low. Expressions for the effective coefficient of friction, the area of the solid-to-solid contact and the torque needed to rotate the bearing are given in terms of its geometry, the viscosity of the lubricant and elapsed time. The mechanism of a bearing with similar geometry and properties, the human hip joint, is compared with this plastic bearing. While their low friction properties arise from the same basic cause, the different natures of their soft deformable materials lead to the hip joint having a much wider range of action. This work is an example of new engineering leading to a fresh insight into an action of Nature, which in turn suggests an improvement in engineering.

2010-01-01

16

Rheodynamic Lubrication of an Externally Pressured Thrust Bearing Using Herschel-Bulkley Fluid with Sinusoidal Injection  

Directory of Open Access Journals (Sweden)

Full Text Available Lubricants with variable viscosity are assuming greater importance for its application in polymer industry, thermal reactors and in biomechanics. With the bearing operations in machines being subject to high speeds, loads, increasing mechanical shearing forces and continually increasing pressure, there has been an increasing interest to use non-Newtonian fluids characterized by a yield value. Some of them, which fit into this class, are Bingham, Casson and Herchel-Bulkley models. In the present work, the problem of an externally pressurized thrust bearing lubricated with Herschel-Bulkley fluid under the sinusoidal flow rate has been investigated. Herschel-Bulkley fluids are characterized by a yield value, which leads to the formation of rigid core in the flow region. The shape and extent of the core has been determined numerically for various values of the Herschel-Bulkley number, power-law index, amplitude of sinusoidal fluid film and time. Numerical solutions have been obtained for the bearing performances such as pressure distribution and load capacity for different values of the Herschel-Bulkley number, power-law index, amplitude of sinusoidal fluid film and time. The effects of sinusoidal injection of the lubricant and the non-Newtonian characteristics on the bearing performances have been discussed.

I.J. Amalraj; S Narasimman; A Kandasamy

2012-01-01

17

Numerical modelling of the flow in the annular multi-recess hydrostatic thrust bearing using CFD methods  

Directory of Open Access Journals (Sweden)

Full Text Available The current research of hydrostatic bearings and hydrostatic slide-ways is far from being over. The topic is constantly evolving, creating new geometries of the sliding bearings, developing new types of friction materials and lubricants. The control elements of hydraulic mechanisms that serve to regulation of the hydrostatic bearings tipping are still in progress. Almost every application has different requirements for the bearings, whether in terms of loading capacity, speed rotation, and also the price. All these aspects should be included in the design of hydrostatic thrust bearings. Thanks to great advances in the development of computer technology and software for numerical modelling, we can simulate real movement of viscous fluids. To create a numerical model of hydrostatic thrust bearing, Ansys Fluent 14.0 software package has been applied. The article describes the basic methods of numerical modelling of the given problem and evaluates the pressure field and the loading capacity of annular multi-recess hydrostatic thrust bearing and its dependence on the change in static pressure.

Kozdera M.; Drbáková S.

2013-01-01

18

The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings - Part I: Theory  

DEFF Research Database (Denmark)

This is Part I of a two-part series of papers describing the effects of high-pressure injection pockets on the operating conditions of tilting-pad thrust bearings. In Part I a numerical model based on the Reynolds equation is developed extending the threedimensional thermoelastohydrodynamic (TEHD) analysis of tilting-pad thrust bearings to include the effects of high-pressure injection and recesses in the bearing pads. The model is applied to the analysis of an existing bearing of large dimensions and the influence of the pocket is analyzed. In the analysis, the high-pressure oil injection used for hydrostatic jacking is turned off (i.e., only the effect of the pocket is studied). It is shown that a shallow pocket positively influences the performance of the bearing because it has characteristics similar to those of a Rayleigh-step bearing. In Part II of the paper (Heinrichson, N., Fuerst, A., and Santos, I. F., 2007, ASME J. Tribol., 129(4), pp. 904–912) measurements of pressure profiles and oil film thickness for a test-pad are compared to theoretical results. The analysis of Part II deals both with flow situations, where the high-pressure injection is turned off, as well as with situations where it is turned on for hydrostatic jacking.

Heinrichson, Niels; Santos, Ilmar

2007-01-01

19

Tribochemistry of Multiply-Alkylated Cyclopentane Oils on DLC-Coated Thrust Bearings.  

Science.gov (United States)

In contrast to typical DLC coatings, hydrogenated DLC (H-DLC) coatings exhibit extremely low friction in vacuum and dry atmospheres, suggesting their potential importance for spacecraft applications. We have conducted a study of H-DLC-coated steel thrust ...

J. R. Lince P. A. Bertrand

2007-01-01

20

Performance of integrated retainer rings in silicon micro-turbines with thrust style micro-ball bearings  

Science.gov (United States)

This work explores the performance of different silicon retainer ring designs when integrated into silicon micro-turbines (SMTs) incorporating thrust style bearings supported on 500 µm diameter steel balls. Experimental performance curves are presented for SMTs with rotor diameters of 5 mm and 10 mm, each with five different retainer designs varying in mechanical rigidity, ball pocket shape and ball complement. It was found that the different retainer designs yielded different performance curves, with the closed pocket designs consistently requiring lower input power for a given rotation speed, and the most rigid retainers giving the best performance overall. Both 5 mm and 10 mm diameter devices have shown repeatable performance at rotation speeds up to and exceeding 20?000 RPM with input power levels below 2 W, and devices were tested for over 2.5 million revolutions without failure. Retainer rings are commonly used in macro-scale bearings to ensure uniform spacing between the rolling elements. The integration of retainers into micro-bearings could lower costs by reducing the number of balls required for stable operation, and also open up the possibility of ‘smart’ bearings with integrated sensors to monitor the bearing status.

Hergert, Robert J.; Hanrahan, Brendan; Ghodssi, Reza; Holmes, Andrew S.

2013-06-01

 
 
 
 
21

Comparison of Models for the Steady-State Analysis of Tilting-Pad Thrust Bearings  

DEFF Research Database (Denmark)

Prediction of the minimum oil film thickness and the maximum temperature on the surface of the bearing pad is crucial in the design and dimensioning of bearings. Friction loss, oil bath temperature and pad deflection are other parameters of interest. Depending on the desired information a numerical model requires different levels of detail. The two dimensional Reynolds equation for pressure in the oil film can be solved isothermally or considering viscosity variations in two or three dimensions, requiring solution of the equations for thermal equilibrium in oil and pad. Knowing the temperature distribution the deflection of the pad due to pressure and thermal bending can be calculated using a flat plate approximation. At the five free sides of the pad heat transfer can be modelled. The temperature distribution at the inlet to the pad can be calculated through equilibrium of thermal energy for the groove between pads and the oil bath temperature from energy equilibrium for the entire bearing. The main theoretical contribution of this paper is the elaboration and comparison of 7 different mathematical models of increasing complexity. The results are compared to experimental data for steady-state operation of a 228 mm outer diameter bearing. It is found that for the given bearing a two dimensional model is sufficient to estimate the minimum oil film thickness and the maximum temperature on the pad surface. Three dimensional modelling does not improve the quality of the results.

Heinrichson, Niels; Santos, Ilmar

2005-01-01

22

On the selection of design parameters of the thrust gas bearing with an outside supercharging  

International Nuclear Information System (INIS)

The problems of stability of high-speed rators in gas bearings have been considered. To provide stable operating conditions, the upper limit of the operating speed range of the rotor, supported on unilinear gas bearings with the outside supercharging, should be selected not exceeding 0.7 of the threshold speed of the vortex instability. The investigations of a number of bearings with various radial gaps and elongations show that maximum threshold speeds are reached at dimensionless parameters of supercharging, lambdasub(s)=0.35-0.45. The decrease of parameters lambdasub(s) results in a deterioration of damping properties of the bearing and an increased sensitivity to the operating loss of balance and external excitation. Due to nonlinear properties of the elastic characteristic of the gas layer, the synchronous resonance frequency and the threshold speed in the range of optimal lambdasub(s) substantially depends on the value of disbalance. With the increase in the disbalance from 0.3-0.4 ?m to 7.7 ?m, the threshold speed decreases by 25-30%. The recommended values of the diameter and the number of feeders, of the radial gap, relative elongation and permissible residual nonequilibrium are given.

1977-01-01

23

2D THD and 3D TEHD analysis of large spindle supported thrust bearings with pins and double layer system used in the three gorges hydroelectric generators  

Science.gov (United States)

A 2D THD model and a 3DTEHD model for large spindle supported thrust bearings were set up and used to analyze the lubrication performance of the Three Gorges test thrust beating withpins and double layer system developed by Alstom Power. The finite difference method was employed to solve the THD model, and the thermal-elasticdeformations in the pad and runner were obtained by the finite element software ANSYS11.0. The data transfer between the THD model and ANSYS11.0 was carried out automatically by an interface program.A detailed comparison between the experimental results and numerical predictions by the two different modelsset up in this paper was carried out. Poor agreement has been found between the theoretical results obtained by 2D THD model and experimental data, while 3D TEHD provides fairly good agreement, confirming the importance of thermal effects and thermal-elastic deformations in both pad and runner.

Huang, B.; Wu, Z. D.; Wu, J. L.; Wang, L. Q.

2012-11-01

24

2D THD and 3D TEHD analysis of large spindle supported thrust bearings with pins and double layer system used in the three gorges hydroelectric generators  

International Nuclear Information System (INIS)

[en] A 2D THD model and a 3DTEHD model for large spindle supported thrust bearings were set up and used to analyze the lubrication performance of the Three Gorges test thrust beating withpins and double layer system developed by Alstom Power. The finite difference method was employed to solve the THD model, and the thermal-elasticdeformations in the pad and runner were obtained by the finite element software ANSYS11.0. The data transfer between the THD model and ANSYS11.0 was carried out automatically by an interface program.A detailed comparison between the experimental results and numerical predictions by the two different modelsset up in this paper was carried out. Poor agreement has been found between the theoretical results obtained by 2D THD model and experimental data, while 3D TEHD provides fairly good agreement, confirming the importance of thermal effects and thermal-elastic deformations in both pad and runner.

2012-11-26

25

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-11-28

26

The influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings: Part II - Comparison Between Theory and Experiment  

DEFF Research Database (Denmark)

This is Part II of a two-part series of papers describing the effects of high pressure injection pockets on the operating conditions of tilting-pad thrust bearings. Measurements of the distribution of pressure and oil film thickness are presented for tilting-pad thrust bearing pads of approximately 100 cm2 surface area. Two pads are measured in a laboratory test-rig at loads of approximately 0.5, 1.5 and 4.0 MPa and velocities of up to 33 m/s. One pad has a plain surface. The other pad has a conical injection pocket at the pivot point and a leading edge taper. The measurements are compared to theoretical values obtained using a three dimensional thermo-elasto-hydrodynamic (TEHD) numerical model. At low and intermediate loads the theoretical pressure distribution corresponds well to the measured values for both pads although the influence of the pocket is slightly underestimated. At high loads large discrepancies exist for the pad with an injection pocket. It is argued that this is likely to be due to the unevenness of the collar surface. The measured and theoretical values of oil film thickness compare well at low loads. At high loads discrepancies grow to up to 25 %. It is argued that this is due to the accuracy of the measurements.

Heinrichson, Niels; Fuerst, Axel

2006-01-01

27

The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings - Part II: Comparison Between Theory and Experiment  

DEFF Research Database (Denmark)

This is Part II of a two-part series of papers describing the effects of high-pressure injection pockets on the operating conditions of tilting-pad thrust bearings. The paper has two main objectives. One is an experimental investigation of the influence of an oil injection pocket on the pressure distribution and oil film thickness. Two situations are analyzed: (i) when the high-pressure oil injection is turned off and (ii) when the highpressure injection is turned on. The other objective is to validate a numerical model with respect to its ability to predict the influence of such a pocket (with and without oil injection) on the pressure distribution and oil film thickness. Measurements of the distribution of pressure and oil film thickness are presented for tilting-pad thrust bearing pads of approx. 100 cm^2 surface area. Two pads are measured in a laboratory test rig at loads of approx. 1.5 MPa and approx. 4.0 MPa and velocities of up to 33 m/s. One pad has a plain surface. The other pad has a conical injection pocket at the pivot point and a leading-edge taper. The measurements are compared to theoretical values obtained using a three-dimensional thermoelastohydrodynamic (TEHD) numerical model. At the low load, the theoretical pressure distribution corresponds well with the measured values for both pads, although the influence of the pocket is slightly underestimated. At the high load, large discrepancies exist for the pad with an injection pocket. It is argued that the discrepancies are due mainly to geometric inaccuracies of the collar surface, although they may to some extent be due to the simplifications employed in a Reynolds equation description of the pocket flow. The measured and theoretical values of oil film thickness compare well at low loads and velocities. At high loads and velocities, discrepancies grow to up to 25%. This is due to the accuracy of the measurements. When using hydrostatic jacking the model predicts the start-up behavior well.

Heinrichson, Niels; Fuerst, Axel

2007-01-01

28

Fluid Lubricated Bearing Construction.  

Science.gov (United States)

A fluid lubricated thrust bearing assembly is described. A first bearing member has a plain bearing surface; a second bearing member has a bearing surface confronting the surface of the first bearing and is provided with at least one spiral groove extendi...

J. R. Dunning H. A. Boorse G. F. Boeker

1976-01-01

29

Fluid Lubricated Bearing Assembly.  

Science.gov (United States)

A support for a loaded rotatable shaft is described. The device consists of: a housing having a fluid-tight cavity encasing an end portion of the shaft; a thrust bearing near the open end of the cavity for supporting the axial thrust of the shaft, the thr...

H. A. Boorse G. F. Boeker J. R. Menke

1976-01-01

30

Magnetic Bearing  

Directory of Open Access Journals (Sweden)

Full Text Available The use of bearings is essential to all types of machines, especially in marine aspects they provide the function of supporting heavier component in a desired position. These bearings have contact with the rotating part and causes surface wear which can be controlled by lubrication. Researches have raised the standards of performance for rotating equipment by providing robust, cost effective, easy to implement magnetic bearing solutions. Use of magnetic bearings in ships can be more advantageous because it is contact –free resulting in no surface wear and hence no need for lubricant, no servicing and can work in clean environment. It has several other benefits like high reliability, clean environments, high speed applications, position and vibration control and can withstand in extreme conditions. Magnetic bearing will also restrict the translational sliding, which is merely a linear case of supporting a rotating object thus use of thrust block also eliminated. Magnetic bearing technology has become viable because of advances in micro-processing controllers that allows for confident and robust active control. This paper discusses more about the construction, principle and working of magnetic bearing in detail.

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

2013-01-01

31

Low-thrust rocket trajectories  

Energy Technology Data Exchange (ETDEWEB)

The development of low-thrust propulsion systems to complement chemical propulsion systems will greatly enhance the evolution of future space programs. Two advantages of low-thrust rockets are stressed: first, in a strong gravitational field, such as occurs near the Earth, freighter missions with low-thrust engines require one-tenth as much propellant as do chemical engines. Second, in a weak gravitational field, such as occurs in the region between Venus and Mars, low-thrust rockets are faster than chemical rockets with comparable propellant mass. The purpose here is to address the physics of low-thrust trajectories and to interpret the results with two simple models. Analytic analyses are used where possible - otherwise, the results of numerical calculations are presented in graphs. The author has attempted to make this a self-contained report. 57 refs., 10 figs.

Keaton, P.W.

1986-01-01

32

Low-thrust rocket trajectories  

Energy Technology Data Exchange (ETDEWEB)

The development of low-thrust propulsion systems to complement chemical propulsion systems will greatly enhance the evolution of future space programs. Two advantages of low-thrust rockets are stressed: first, in a strong gravitational field, such as occurs near the Earth, freighter missions with low-thrust engines require one-tenth as much propellant as do chemical engines. Second, in a weak gravitational field, such as occurs in the region between Venus and Mars, low-thrust rockets are faster than chemical rockets with comparable propellant mass. The purpose here is to address the physics of low-thrust trajectories and to interpret the results with two simple models. Analytic analyses are used where possible - otherwise, the results of numerical calculations are presented in graphs. The author has attempted to make this a self-contained report.

Keaton, P.W.

1987-03-01

33

Micro thrust and heat generator  

Energy Technology Data Exchange (ETDEWEB)

A micro thrust and heat generator have a means for providing a combustion fuel source to an ignition chamber of the micro thrust and heat generator. The fuel is ignited by a ignition means within the micro thrust and heat generator`s ignition chamber where it burns and creates a pressure. A nozzle formed from the combustion chamber extends outward from the combustion chamber and tappers down to a narrow diameter and then opens into a wider diameter where the nozzle then terminates outside of said combustion chamber. The pressure created within the combustion chamber accelerates as it leaves the chamber through the nozzle resulting in pressure and heat escaping from the nozzle to the atmosphere outside the micro thrust and heat generator. The micro thrust and heat generator can be microfabricated from a variety of materials, e.g., of polysilicon, on one wafer using surface micromachining batch fabrication techniques or high aspect ratio micromachining techniques (LIGA). 30 figs.

Garcia, E.J.

1998-11-17

34

Micro thrust and heat generator  

Energy Technology Data Exchange (ETDEWEB)

A micro thrust and heat generator has a means for providing a combustion fuel source to an ignition chamber of the micro thrust and heat generator. The fuel is ignited by a ignition means within the micro thrust and heat generator's ignition chamber where it burns and creates a pressure. A nozzle formed from the combustion chamber extends outward from the combustion chamber and tappers down to a narrow diameter and then opens into a wider diameter where the nozzle then terminates outside of said combustion chamber. The pressure created within the combustion chamber accelerates as it leaves the chamber through the nozzle resulting in pressure and heat escaping from the nozzle to the atmosphere outside the micro thrust and heat generator. The micro thrust and heat generator can be microfabricated from a variety of materials, e.g., of polysilicon, on one wafer using surface micromachining batch fabrication techniques or high aspect ratio micromachining techniques (LIGA).

Garcia, Ernest J. (Albuquerque, NM)

1998-01-01

35

Big bearings. Unsung hero; Kyodaina jikuuke. Hitome ni tsukanai hatarakimono  

Energy Technology Data Exchange (ETDEWEB)

This paper introduces examples of the use of big bearings. Bearings are divided largely into those used for radial load supporting and those used for thrust load supporting, while big bearings are often used for the latter usage. Thrust bearings include a cutter heat supporting bearing for tunnel excavator working underground, in addition to those used for swing motion of parabolic antennas and tower cranes. A bearing used in an excavator has an outer diameter of about half that of the excavator. The outer diameter of a shielding machine practically used in tunnel drilling currently has an outer diameter of 14,140 mm, and the outer diameter of the bearing is 7200 mm (bearing weighing 45 tons). Other big thrust bearings may include a swing tower swinging thrust bearing used in a continuous casting facility. Big radial bearings are used in iron and steel making facilities. This paper describes two examples of bearings used in this application. A spherical roller bearing to support converter trunion should be of an ultra big size to withstand total weight of about 1400 tons composed of a converter weight and weight of steel to be processed. A four-row cylindrical roller bearing to support the backup roll of a thick plate rolling mill is a bearing with durability against large loads to support reduction rolls whose size have become increasingly large. 2 refs., 5 figs.

Nanba, S. [Koyo Seiko Co. Ltd., Osaka (Japan)

1997-03-05

36

Bearing construction for refrigeration compresssor  

Energy Technology Data Exchange (ETDEWEB)

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

Middleton, Marc G. (Wyoming, MI); Nelson, Richard T. (Worthington, OH)

1988-01-01

37

Micro thrust and heat generator  

Science.gov (United States)

The present invention relates generally to micromachines such as microengines or micromotors. More specifically, the invention is directed to a micro rocket which functions as a source of heat and thrust, and utilizes chemical energy to drive or power micromechanical apparatuses. The invention is adaptable to applications involving defense, bio-medical, manufacturing, consumer product, aviation, automotive, computer, inspection, and safety systems. A micro thrust and heat generator has a means for providing a combustion fuel source to an ignition chamber of the micro thrust and heat generator. The fuel is ignited by a ignition means within the micro thrust and heat generator`s ignition chamber where it burns and creates a pressure. A nozzle formed from the combustion chamber extends outward from the combustion chamber and tappers down to a narrow diameter and then opens into a wider diameter where the nozzle then terminates outside of said combustion chamber. The pressure created within the combustion chamber accelerates as it leaves the chamber through the nozzle resulting in pressure and heat escaping from the nozzle to the atmosphere outside the micro thrust and heat generator. The micro thrust and heat generator can be microfabricated from a variety of materials, e.g., of polysilicon, on one wafer using surface micromachining batch fabrication techniques or high aspect ratio micromachine techniques (LIGA).

Garcia, E.J.

1995-12-31

38

Geochronology evidences for tectonic deformation of Dabashan fold-thrust belt in central China  

International Nuclear Information System (INIS)

The chronology of tectonic deformation event of Dabashan fold-thrust belt was quantitatively studied based on systematic analysis of fission track, K-Ar thermo- chronology and electron-spin resonance (ESR) dating. The results indicate that the tectonic activity event of North Dabashan fold-thrust belt occurred at 232-195 Ma. This tectonic event may be related to the collision with Yangtze block and North China block. The results also show that the tectonic event of South Dabashan fold-thrust belt happened at 133-100 Ma, 70-60 Ma, 48-33 Ma and 12 Ma. And these ages bear juvenility gradually from northeast to southwest, which is good match of the geometry and kinematics characteristic of tectonic spreading deformation in Dabashan fold-thrust belt. These geochronology data provid new constrains for better understanding the tee- tonic successively spreading deformation of Dabashan fold-thrust belt. (authors)

2008-01-01

39

Thrust Coefficients, Thrust Deflection Angles, and Nondimensional Moments for Nozzles with Oblique Exit Planes.  

Science.gov (United States)

Nozzles with oblique exit planes, scarfed nozzles, are encountered in aerospace applications such as reaction control and thrust reversal systems. This document provides thrust coefficient, thrust deflection angle, and nondimensional turning moment data f...

W. W. Phillips R. A. Fiedler R. G. Hopcroft

1968-01-01

40

A simplified thermohydrodynamic model for fluid film bearings. Final report, February 15, 1992--February 15, 1994  

Energy Technology Data Exchange (ETDEWEB)

We aim to develop a simplified yet realistic model of fluid film lubrication under thermohydrodynamic conditions, with significant thermal and elastic deformation of the bearing pads. The principal thrust is transfer of technology from the researcher to the industrial designer: the end product will include two user-friendly computer programs, one for journal bearings and the other for thrust bearings, to be used for bearing design in interactive mode on a personal computer.

Szeri, A.Z. [Pittsburgh Univ., PA (United States). Dept. of Mechanical Engineering

1994-03-01

 
 
 
 
41

Load responsive hydrodynamic bearing  

Energy Technology Data Exchange (ETDEWEB)

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

Kalsi, Manmohan S. (Houston, TX); Somogyi, Dezso (Sugar Land, TX); Dietle, Lannie L. (Stafford, TX)

2002-01-01

42

Bearing system  

Energy Technology Data Exchange (ETDEWEB)

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.

Kapich, Davorin D. (Carlsbad, CA)

1987-01-01

43

Thrust Vector Control System Study for a Large Liquid Booster.  

Science.gov (United States)

This effort consisted of evaluating six thrust vector control systems for application on a Large Liquid Booster. The thrust vector control systems evaluated were liquid injection thrust vector control, hot gas secondary injection thrust vector control and...

D. Stump V. Olivier

1968-01-01

44

Thrust control system design of ducted rockets  

Science.gov (United States)

The investigation of the thrust control system is aroused by the need for propulsion system of ducted rockets. Firstly the dynamic mathematical models of gas flow regulating system, pneumatic servo system and ducted rocket engine were established and analyzed. Then, to conquer the discussed problems of thrust control, the idea of information fusion was proposed to construct a new feedback variable. With this fused feedback variable, the thrust control system was designed. According to the simulation results, the introduction of the new fused feedback variable is valid in eliminating the contradiction between rapid response and stability for the thrust control system of ducted rockets.

Chang, Juntao; Li, Bin; Bao, Wen; Niu, Wenyu; Yu, Daren

2011-07-01

45

Polar Bear  

Science.gov (United States)

This site from the World Wildlife Fund (WWF) International provides general information about polar bears as well as data on the movements of two radio-collared bears, along with the ice status, through a series of online maps.

2007-01-01

46

The R and D D's bearing test benches  

International Nuclear Information System (INIS)

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

1997-01-01

47

Hydrocarbons, blind thrusts, and upper detachments  

Energy Technology Data Exchange (ETDEWEB)

Oil and gas occur in the foreland margins of deformed belts around the world, concealed beneath the mountain-facing flank of a foreland syncline. Such a syncline is formed by wedging of blind, foreland-directed thrusts against an upper detachment zone that extends out to the synclinal axis. Examples include mature exploration areas such as the Carpathian foothills of Rumania and the foothills of the Canadian Cordillera, and the foreland margins of the Appalachians, Ouachitas, and Brooks Range. Other examples have been reported from several sectors of the Alpine-Himalayan and Andean orogens. The upper detachment was originally horizontal, uplifted by the blind thrust beneath it. While there is no way of measuring how far into a thrust belt an upper detachment extended before it was removed by erosion, computer modeling can reconstruct thrust belts within the constraints imposed by inclusion of an upper detachment. An example from Canada shows that the entire southern Alberta foothills belt can be modeled this way. This is consistent with the observed plunge of the Alberta thrust belt along strike beneath the fold belt of northeastern British Columbia, where wells spudded in folds penetrate blind subsurface thrusts. These data suggest that, like folded faults, blind thrust and upper detachments are common features of deformed belts. Failure to recognize them can result in severely underestimating the extent of thrusting, and consequently downgrading the hydrocarbon potential of a deformed belt.

Jones, P.B.

1984-04-01

48

Thrust vectoring for Eurofighter - The first steps  

Energy Technology Data Exchange (ETDEWEB)

Thrust vectoring has the potential to provide significant improvements in combat aircraft performance and stability. As Eurofighter Typhoon moves into production, ITP and MTU are pursing a research and technology acquisition project to investigate the design of a thrust vectoring nozzle system suitable for future application to the EJ2000 engine. This paper describes the current status and progress of this project. (authors)

Ikaza, D. [Project Manager, Nozzles With Industria de Turbo Propulsores, Muenchen (Germany); Rausch, Ch. [Project Manager, Thrust Vector Engine Control With MTU Motoren-und Turbinen-Union, Muenchen (Germany)

2000-02-01

49

AXIAL THRUST IN THE IMPELLER PUMPS  

Directory of Open Access Journals (Sweden)

Full Text Available The system of forces acting at the pump rotors and also the influence of the working conditions on the dimensions and distribution of the axial thrust are presented.The essential formulas, for the calculation of the axial thrust value are given on the basis of the most recent research.

Zbigniew Jankowski; ?ukasz Kurpisz

1972-01-01

50

Cage unbalance and wear in ball bearings  

Energy Technology Data Exchange (ETDEWEB)

The dynamic cage interactions in a high-speed ball bearing are modeled as a function of unbalance. The resulting cage wear rates and overall power loss in the bearing are parametrically evaluated with varying levels of unbalance in the cage. Both outer and inner race guided cages are considered with a combined thrust and rotating radial load on the bearing. Although the level of unbalance, beyond which the cage interactions become excessive, is almost equal for both outer and inner race guided cages, cage guidance on the stationary outer race appears to be somewhat more favorable, both in terms of power loss and cage wear. (orig.).

Gupta, P.K. (PKG, Inc., Clifton Park, NY (USA))

1991-07-05

51

Journal bearing  

Science.gov (United States)

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.

Menke, John R. (New York, NY); Boeker, Gilbert F. (New York, NY)

1976-05-11

52

The polar bear phenomena  

Energy Technology Data Exchange (ETDEWEB)

Results from measuring the thermal profile of polar bear pelts, reflectiveness of the pelts, and total thermal conversion data lead to the conclusion that the pelts from an ultra-efficient thermal diode for solar-thermal conversion. The transfer of the thermal energy from the surface of the fur to the skin where it is absorbed cannot be thermal, and therefore must be radiative. This process must have an efficiency of better than 90:0090 percent to account for measured values. The radiative transfer process is not known at present. To understand it, a detailed knowledge of the microscopic parameters of the pelts must be obtained. This is the current thrust of the polar solar research. If the process can be understood and synthesized,it will provide a major breakthrough in the area of solar-thermal energy conversion.

Maw, P.K. (United Kingdom Ingersoll-Rand Sales Company, Ltd., Horwich, Bolton Lancashire, BL6 6JN (GB)); Lane, M.T.

1990-02-01

53

Low thrust chemical rocket technology  

Science.gov (United States)

An on-going technology program to improve the performance of low thrust chemical rockets for spacecraft on-board propulsion applications is reviewed. Improved performance and lifetime is sought by the development of new predictive tools to understand the combustion and flow physics, introduction of high temperature materials and improved component designs to optimize performance, and use of higher performance propellants. Improved predictive technology is sought through the comparison of both local and global predictions with experimental data. Predictions are based on both the RPLUS Navier-Stokes code with finite rate kinetics and the JANNAF methodology. Data were obtained with laser-based diagnostics along with global performance measurements. Results indicate that the modeling of the injector and the combustion process needs improvement in these codes and flow visualization with a technique such as 2-D laser induced fluorescence (LIF) would aid in resolving issues of flow symmetry and shear layer combustion processes. High temperature material fabrication processes are under development and small rockets are being designed, fabricated, and tested using these new materials. Rhenium coated with iridium for oxidation protection was produced by the Chemical Vapor Deposition (CVD) process and enabled an 800 K increase in rocket operating temperature. Performance gains with this material in rockets using Earth storable propellants (nitrogen tetroxide and monomethylhydrazine or hydrazine) were obtained through component redesign to eliminate fuel film cooling and its associated combustion inefficiency while managing head end thermal soakback. Material interdiffusion and oxidation characteristics indicated that the requisite lifetimes of tens of hours were available for thruster applications. Rockets were designed, fabricated, and tested with thrusts of 22, 62, 440 and 550 N. Performance improvements of 10 to 20 seconds specific impulse were demonstrated. Higher performance propellants were evaluated: Space storable propellants, including liquid oxygen (LOX) as the oxidizer with nitrogen hydrides or hydrocarbon as fuels. Specifically, a LOX/hydrazine engine was designed, fabricated, and shown to have a 95 pct theoretical c-star which translates into a projected vacuum specific impulse of 345 seconds at an area ratio of 204:1. Further performance improvment can be obtained by the use of LOX/hydrogen propellants, especially for manned spacecraft applications, and specific designs must be developed and advanced through flight qualification.

Schneider, Steven J.

1992-11-01

54

Engine bearings  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a hydrodynamic journal bearing combination comprising: a rotary journal shaft having a circular cross section; a journal bearing surrounding the rotary journal shaft. The journal bearing has at least two symmetrical arcuate bearing surfaces, each arcuate surface having the same radius. The radius is slightly greater than that of the rotary journal shaft. Each arcuate bearing surface defines less than 180/sup 0/ and has a mid point intermediate it ends. The arcuate bearing surfaces are disposed with their mid points diametrically opposed. The journal shaft is positioned within the area covered by the two arcuate surfaces whereby a small clearance is maintained therebetween at all points under both load and no-load lubricant filling the aforesaid clearance between the journal shaft and the two arcuate surfaces.

Showalter, M.R.

1987-05-26

55

Bearing seal  

Energy Technology Data Exchange (ETDEWEB)

Various machinery which includes pivotal bearings, as for example in conveyor drive chains, especially those used for bulk material as for example in various mining operations, is exposed to particularly severe operating conditions including exposure to contamination with extraneous particulate material such as coal dust in the case of coal mining machinery. Conventional conveyor drive chains in particular include a large number of bearing surfaces since each link in the chain is connected to neighbouring links by two pivot pins, and each of these bearing surfaces is exposed to ingress of foreign, more or less abrasive, matter and hence to wear resulting in loss of performance and eventual failure of the chain. This invention related to a sealed pivotal bearing assembly comprising a pivot pin mounted in an annular bearing member for pivotal displacement through a limited angle relative thereto. An annular sealing means in the form of a resiliently torsionally deformable collar has first and second annular portion fixedly secured in fluid tight manner to respective ones of the bearing member and the pivot pint thereby to seal across a bearing interface therebetween, so that in use of the assembly, the pivot pin may be pivoted relative to the bearing member whilst maintaining a fluid-tight seal around the bearing interface therebetween.

Hodgson, A.

1989-08-22

56

Pressure balanced bearing assembly for downhole motors  

Energy Technology Data Exchange (ETDEWEB)

A bearing assembly is described for assembly on a fluid-operated downhole motor on the fluid outlet end comprising a tubular housing having an inlet and an outlet for flow of fluid there through, a stator supported in a fixed position in the housing, a rotor supported for rotary movement in the stator. The assembly comprises a bearing housing adapted to be removably secured on the outlet end of the motor housing; a shaft for supporting a drill bit and adapted to be connected to the rotor and supported for rotary movement in the bearing housing; the housing being operable to receive drilling fluid under pressure flowing from the motor for discharge there through into the borehole; and bearing means cooperable with the shaft and the bearing housing to carry a longitudinally downward thrust load of the shaft.

Maurer, W.C.; Mc Donald, W.J.

1987-05-19

57

Troubleshooting bearing problems during the uprating of an existing steam turbine installation  

Energy Technology Data Exchange (ETDEWEB)

Paper manufacturing relies heavily on large quantities of steam and electrical power. Paper plants historically generate steam for the papermaking process and generate electricity via a steam turbine and alternator. This paper details the economic re-rating of a thrust bearing following repeated failures of an existing steam turbine installation at a UK paper mill. This involved the inspection of failed components, fundamental analysis of the turbine operating conditions and ultimately a re-design of the thrust bearing assembly. (author)

Maw, S. [Neale Consulting Engineers Ltd., Farnham (United Kingdom); Abbott-Garder, J. [St Regis Paper Co. Ltd., Somerset (United Kingdom); Kendrick, S. [Sulzer Roteq Services, Leeds (United Kingdom)

2000-07-01

58

Aircraft Performance Optimization with Thrust Vector Control.  

Science.gov (United States)

The objective of this thesis is to determine to what extent a highly-maneuverable aircraft's overall performance capability is enhanced by thrust-vectoring nozzles. The resulting performance capabilities are compared to a baseline configuration with non-t...

M. S. Fellows

1985-01-01

59

Failure of GIMBAL bearing in directional GYRO  

International Nuclear Information System (INIS)

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

2003-01-01

60

Laser plasma thruster continuous thrust experiment  

Science.gov (United States)

The laser plasma thruster (LPT) is a new microthruster for small satellites. We report on development and testing of a prototype LPT. Some advantages of the LPT are: thruster voltage 4 V, mass less than 1 kg, power-to-thrust ratio 10 kW/newton and Isp up to 1000 seconds. Typical thrust level is 250 (mu) N with PVC fuel. Thrust of 1 mN is expected with energetic fuel. The pre-prototype continuous thrust experiment includes the laser mount and heat sink, lens mounts, and focusing mechanism, which are coupled to the target material transport mechanism. The target material is applied to a transparent plastic tape, and the laser is focused on a series of tracks on the tape. The tape drive hardware and laser drive electronics, are described, as well as the control and diagnostic software. Design, construction, and calibration of the thrust stand are described. During continuous operation, the exhaust plume is deflected in the direction of the moving tape. When the laser is operated in pulsed mode, the exhaust plume is perpendicular to the tape (parallel to the optical axis). This provides some thrust vector control.

Luke, James R.; Phipps, Claude R.; McDuff, G. Glen

2002-09-01

 
 
 
 
61

FROM STUDIES ON THE THRUST IN SWIMMING  

Directory of Open Access Journals (Sweden)

Full Text Available Swimming speed is determined by many factors, including weight preparation of the swimmer which is one of the most important ones. This power is directly related to the speed a swimmer can reach in water, that is the value of thrust. The aim of the study was to establish the level of thrust and swimming speed of the 2nd year students (n=20) of the University School of Physical Education (USPE) in Pozna? and to compare them with the results of study from 1983 in which the 4th year students (n=20) of the USPE in Pozna? were studied. The current study was carried out in the context of the long-term changes in swimming technique. Research methods: measurement of thrust in real conditions was performed using a prototype device for the measurement of thrust of a swimmer which makes it possible to register the force in the water environment; swimming speed was established on the basis of the time needed to cover the distance of 25 metres, according to the regulations of the Polish Swimming Association. Conclusions: the students taking part in the 1983 study had higher values of thrust, but a lower speed than the students taking part in the 2006 study, which suggests that apart from the thrust the technique of swimming has a important influence of the swimming speed.

Lutomski, P.; Stankowski, T.; Konarski, J.; Pietrusik, K.; Ciereszko, A.; Strzelczyk, R.

2008-01-01

62

PASSIVE NON-CONTACTING SMART BEARING SUSPENSION FOR TURBO BLOOD-PUMPS.  

UK PubMed Central (United Kingdom)

The ultimate in suplicity and reliability, an axial-flow blood pump is supported by an all passive contact-free hybrid bearing suspension that can measure differential pump pressure. The preferred suspension consists of a radial hydrodynamic journal bearing with axial magnetic thrust bearings. The thrust bearing consists of repulsion magnet pairs positioned at each end of the rotor. This holds bidirectional loads with a stable restoring force (negative axial stiffness). Rotor axial position shifts with load and is monitored with a position sensor to inherently provide pump differential pressure (which may be used to physiologically control pump flow rate). The hydrodynamic radial and "smart" axial magnet thrust bearings use large gaps to eliminate hemolysis and are actively washed out under pressure with fresh blood to eliminate thrombosis.

GOLDOWSKY MICHAEL P

63

PASSIVE NON-CONTACTING SMART BEARING SUSPENSION FOR TURBO BLOOD-PUMPS  

UK PubMed Central (United Kingdom)

The ultimate in suplicity and reliability, an axial-flow blood pump is supported by an all passive contact-free hybrid bearing suspension that can measure differential pump pressure. The preferred suspension consists of a radial hydrodynamic journal bearing with axial magnetic thrust bearings. The thrust bearing consists of repulsion magnet pairs positioned at each end of the rotor. This holds bidirectional loads with a stable restoring force (negative axial stiffness). Rotor axial position shifts with load and is monitored with a position sensor to inherently provide pump differential pressure (which may be used to physiologically control pump flow rate). The hydrodynamic radial and "smart" axial magnet thrust bearings use large gaps to eliminate hemolysis and are actively washed out under pressure with fresh blood to eliminate thrombosis.

GOLDOWSKY MICHAEL P

64

Passive non-contacting smart bearing suspension for turbo blood-pumps  

UK PubMed Central (United Kingdom)

The ultimate in suplicity and reliability, an axial-flow blood pump (18) is supported by an all passive contact-free hybrid bearing suspension that can measure differential pump pressure. The preferred suspension consists of a radial hydrodynamic journal bearing with axial magnetic thrust bearings (4,4'). The thrust bearing consists of repulsion magnet pairs (7) positioned at each end of the rotor. This holds bidirectional loads with a stable restoring force (negative axial stiffness). Rotor axial position shifts with load and is monitored with a position sensor (16) to inherently provide pump differential pressure (which may be used to physiologically control pump flow rate). The hydrodynamic radial and "smart" axial magnet thrust bearings use large gaps (5,5') to eliminate hemolysis and are actively washed out under pressure with fresh blood to eliminate thrombosis.

Goldowsky Michael P.

65

Effect of blade outlet angle on radial thrust of single-blade centrifugal pump  

Science.gov (United States)

Single-blade centrifugal pumps are widely used as sewage pumps. However, a large radial thrust acts on a single blade during pump operation because of the geometrical axial asymmetry of the impeller. This radial thrust causes vibrations of the pump shaft, reducing the service life of bearings and shaft seal devices. Therefore, to ensure pump reliability, it is necessary to quantitatively understand the radial thrust and clarify the behavior and generation mechanism. This study investigated the radial thrust acting on two kinds of single-blade centrifugal impellers having different blade outlet angles by experiments and computational fluid dynamics (CFD) analysis. Furthermore, the radial thrust was modeled by a combination of three components, inertia, momentum, and pressure, by applying an unsteady conservation of momentum to this impeller. As a result, the effects of the blade outlet angle on both the radial thrust and the modeled components were clarified. The total head of the impeller with a blade outlet angle of 16 degrees increases more than the impeller with a blade outlet angle of 8 degrees at a large flow rate. In this case, since the static pressure of the circumference of the impeller increases uniformly, the time-averaged value of the radial thrust of both impellers does not change at every flow rate. On the other hand, since the impeller blade loading becomes large, the fluctuation component of the radial thrust of the impeller with the blade outlet angle of 16 degrees increases. If the blade outlet angle increases, the fluctuation component of the inertia component will increase, but the time-averaged value of the inertia component is located near the origin despite changes in the flow rate. The fluctuation component of the momentum component becomes large at all flow rates. Furthermore, although the time-averaged value of the pressure component is almost constant, the fluctuation component of the pressure component becomes large at a large flow rate. In addition to the increase of the fluctuation component of this pressure component, because the fluctuation component of the inertia and momentum components becomes large (as mentioned above), the radial thrust increases at a large flow rate, as is the case for the impeller with a large blade outlet angle.

Nishi, Y.; Fukutomi, J.; Fujiwara, R.

2012-11-01

66

Thrust vector control control using internal airfoils  

Energy Technology Data Exchange (ETDEWEB)

This patent describes an exhaust nozzle for an engine which generates thrust expulsion of gaseous products of fuel combustion. It comprises: a generally axisymmetric housing defined along a central thrust axis including a wall structure defining an exhaust duct, and axially adjacent radially inwardly converging portion, throat portion and radially outwardly diverging portion; and at least one airfoil sized to protrude into the exhaust a distance corresponding to about 15 to 35 percent of diameter of the throat portion disposed within the divergent portion at a location axially spaced from the axis portion a distance corresponding to from 20 per cent to 25 per cent of the axial extent of the divergent portion, the airfoil mounted on the wall structure for rotation about an axis substantially perpendicular to the thrust axis.

Herup, E.J.; Franke, M.E.; Friddell, J.H.

1992-10-13

67

Low thrust NTP for manned Mars operations  

International Nuclear Information System (INIS)

[en] The impact on manned Mars operations of selecting a nuclear thermal propulsion (NTP) module with a relatively low total thrust, in the 222--445 kN (50--100 klbf) range, is explored. The propulsion module may consist of one or more engines. Selection of a low total thrust is robust across a wide range of payload masses provided perigee kicks are utilized for trans-Mars insertion (TMI). The longer time taken for TMI when using a low total thrust and perigee kicks allows for extensive system evaluation before commitment to Earth escape, but will require fuels with lifetimes of at least a few hours. Longer fuel life could be obtained without using advanced fuels by operating at lower fuel temperatures later in the mission. The additional traversals through the Van Allen belts inherent with using perigee kicks for TMI does not significantly increase the radiation exposure of the crew. Negative reactivity from xenon buildup between perigee kicks can be mitigated by coasting on the intermediate orbits, by altering the selection of the intermediate orbits, by deep throttling, or by building in sufficient excess reactivity. Thrust misalignments of a realistic magnitude do not pose an Earth impact hazard. Engine crosstalk in clusters is a very manageable problem. High propulsion module reliability can be achieved with a propulsion module consisting of a cluster of three or four small engines without dropping the module thrust-to-weight ratio below an acceptable level. A total design thrust in the 222--445 kN range is high enough for Earth return with only one of the engines of the cluster operating

1993-01-10

68

Design and fabrication of an ion thruster thrust test stand; Ion engine suiryoku shiken sochi no sekkei to seisaku  

Energy Technology Data Exchange (ETDEWEB)

A thrust test standard that can directly measure the thrust of an ion thruster was designed and manufactured, and the thrust of an xenon ion thruster was measured. The whole measurement equipment is called a pendulum. The measurement equipment consists of an engine installation block (thrust detector), arm block, bearing, and counter balance block. The pendulum arm is 1 meter in length, and the total weight is supported by right and left knife edges. The test standard is a vacuum container. The size is 850 mm in width and 2135 mm in height. For the thrust of the thruster, the displacement value of a pendulum is measured by a laser displacement gauge. The specimen is a cusp-type xenon ion thruster. The supplied propellent is injected into the discharge room, extracted as an ion, then accelerated. The test result showed that the relation between the poise weight and displacement value has high reproducibility. Moreover, the relation is in proportional state and can be used for actual thrust measurement. However, it became clear that the calibration method of this time contains many problems in precision. 11 refs., 15 figs., 3 tabs.

Miyazaki, K. [National Aerospace Laboratory, Tokyo (Japan)

1994-11-01

69

Development of the High Efficiency Reciprocating Compressor by Clarification of Loss Generation in Bearings  

Science.gov (United States)

An analytical model for mixed lubrication in bearings of reciprocating compressors for refrigerators has been developed and a new bearing which could decrease its friction losses by 20% has been designed. Because friction losses, which are generated in the journal and thrust bearing of our reciprocating compressor, are estimated to be one-third or more of all losses, it is an essential issue to decrease bearing losses to design more efficient compressors. The developed analytical model can calculate the shaft posture which changes during its rotation. Based on this posture, losses due to oil viscosity and solid contact at both the thrust and journal bearing are specified. By using this model, how and how much friction loss is generated in each bearing is clarified. A specific approach to decrease bearing losses is clarified and the validity of the developed model is confirmed by the experiment. By using the model, improvement of performance of our compressor by 2.5% has been achieved.

Matsui, Masaru; Kitsunai, Yoko; Inagaki, Ko

70

Lifting Surface Theory for Thrust Augmenting Ejectors.  

Science.gov (United States)

The circulation theory of airfoil lift has been applied to predict the static performance of thrust augmenting ejectors. The ejector shroud is considered to be 'flying' in the velocity field induced by the entrainment of the primary jets, so that the thru...

P. M. Bevilaqua

1982-01-01

71

Thrust faulting and hydrocarbon generation: reply  

Energy Technology Data Exchange (ETDEWEB)

This paper is a rebuttal of an earlier paper trying to refute the claims of these authors. They believe this reply illustrates that the simplifications used by Warner and Royse (1987) in their model are generally inappropriate to describe the thermal history of units in the Western Overthrust belt, as well as other overthrust regions. Although their shortcuts produce results that are generally consistent with measured maturity values for some specific modeling sites, the differences in maturation history and the mismatch for the general thrust case make their model a less effective predictive tool. At this stage in the understanding of overthrust thermal processes, you cannot predict a priori when the thermal effects of thrusting will be significant and when they will be minimal. Defining the exact relationship between thrusting and hydrocarbon accumulations in overthrust areas requires additional work and data collection. In particular, workers must consider case histories where the hanging wall contains thick sequences of resistant strata. By incorporating additional constraints, instead of returning to the simplified assumption of constant thermal gradients in tectonic regions, the understanding of the evolution and maturation history of thrust belts is improved.

Edman, J.D.; Furlong, K.P.

1987-07-01

72

Application of thrust vector control on airships ?????????? ???????????? ??????? ???? ?? ?????????? ???????????? ?????????? ??????? ???? ?? ??????????  

Directory of Open Access Journals (Sweden)

Full Text Available  Concepts of manual and automatic thrust vector control of a modern airship are investigated and compared by simulation of the vehicle movement dynamics. Airship movement simulation with application of the mathematical apparatus of differential transformations is carried out. ??????????? ????????? ??????? ? ??????????????? ?????????? ??????????? ??????? ???? ???????????? ????????? ????? ????????????? ???????? ???????? ???????? ? ??????????? ??????????????? ???????? ???????????????? ??????????????. ?????????? ????????? ??????? ? ????????????? ????????? ??????????? ??????? ???? ????????? ????????? ?????? ??????????? ???????? ???? ??????? ? ????????????? ????????????? ??????? ????-??????????? ???????????.

?.?. ???????; ?.?. ???????

2005-01-01

73

Associations of varus thrust and alignment with pain in knee osteoarthritis.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To investigate associations of varus thrust and varus static alignment with pain in patients with knee osteoarthritis (OA). METHODS: This was a cross-sectional study of participants from a randomized controlled trial of vitamin D treatment for knee OA. Participants were video recorded while walking and scored for presence of varus thrust. Static alignment was measured on standard posteroanterior knee radiographs. Pain questions from the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire were used to assess symptoms. We calculated means for total WOMAC pain in relation to varus thrust and static varus alignment (i.e., corrected anatomic alignment<178 degrees). Ordinal logistic regressions were performed, with responses on individual WOMAC pain questions as the outcomes and varus thrust and varus alignment as the predictors. RESULTS: There were 82 participants, 60% of whom were female. The mean±SD age was 65.1±8.5 years, and the mean±SD body mass index was 30.2±5.4 kg/m2. The mean total WOMAC pain score was 6.3 versus 3.9, respectively, in those with versus without definite varus thrust (P=0.007) and 5.0 versus 4.2 in those with versus without varus alignment (P=0.36). Odds ratios for pain with walking and standing were 4.7 (95% confidence interval 1.8-11.9) and 5.5 (95% confidence interval 2.2-14.2), respectively, in those with and those without definite varus thrust. There were no significant associations between varus alignment and responses to individual WOMAC pain questions. Sensitivity analyses suggested that varus classified using a more stringent definition might have been associated with pain on walking and standing. CONCLUSION: In patients with knee OA, varus thrust, and possibly varus static alignment, were associated with pain, specifically during weight-bearing activities. Treatment of varus thrust (e.g., via bracing or gait modification) may lead to improvement of symptoms.

Lo GH; Harvey WF; McAlindon TE

2012-07-01

74

Piston and bearing assemblies  

Energy Technology Data Exchange (ETDEWEB)

A four-stroke cycle engine piston assembly is described comprising a connecting rod having a generally cylindrical piston pin secured to one end of the rod, a skirt member having an outer wall with a pair of oppositely disposed piston pin receiving openings through the wall, the piston pin extending into the openings and supporting the skirt for oscillating motion about the piston pin, a head member having a crown section connected with a peripheral depending ring belt section above the skirt member and having a piston pin connecting section internally depending from the crown section and extending within the skirt member. The pin connecting section includes a pair of oppositely disposed downwardly extending pin encircling arms defining oppositely aligned pin receiving openings interconnected along upper edges by a downwardly opening saddle portion extending between the arms, and a downwardly opening arcuate primary recess of less than semicylindrical extent in the saddle portion and extending outwardly into the pin receiving openings and a part cylindrical bearing shell insert of less than semicylindrical extent in the primary recess and engaging the piston pin to carry primary axial thrust forces therebetween.

Russell, R.A.; Moore, T.J.; Schafer, T.V.

1987-02-24

75

Thrusting and gravel progradation in foreland basins: A test of post-thrusting gravel dispersal  

Energy Technology Data Exchange (ETDEWEB)

The use of gravels as syntectonic indicators of thrusting has recently been questioned by foreland-basin models that assign gravels to a post-thrusting interval of progradation, except in very proximal areas. On the basis of precise temporal control provided by magnetostratigraphically dated sections, the history of gravel progradation after a major thrusting and uplift event in the northwestern Himalaya is shown to be a virtually syntectonic phenomenon. Despite considerable crustal subsidence driven by a thick-skinned thrust, gravels prograded {approximately} 70 km during a 1.5-m.y.-long thrusting event. By 3 m.y. after the start of thrusting, gravels extended more than 110 km into the basin. Although delayed gravel progradation appears appropriate for many Rocky Mountain foreland basins, it is clearly not valid for the Himalaya. The authors attribute the difference in depositional response between these basins to difference in the quantity of sediment supplied to them (sediment starved vs. overfilled), the availability of resistates in the source area, and the size of the antecedent drainage.

Burbank, D.W.; Beck, R.A.; Hobbs, R. (Univ. of Southern California, Los Angeles (USA)); Raynolds, R.G.H. (Amoco Production Company, Houston, TX (USA)); Tahirkheli, R.A.K. (Peshawar Univ. (Pakistan))

1988-12-01

76

Relationship between Biomechanical Characteristics of Spinal Manipulation and Neural Responses in an Animal Model: Effect of Linear Control of Thrust Displacement versus Force, Thrust Amplitude, Thrust Duration, and Thrust Rate.  

UK PubMed Central (United Kingdom)

High velocity low amplitude spinal manipulation (HVLA-SM) is used frequently to treat musculoskeletal complaints. Little is known about the intervention's biomechanical characteristics that determine its clinical benefit. Using an animal preparation, we determined how neural activity from lumbar muscle spindles during a lumbar HVLA-SM is affected by the type of thrust control and by the thrust's amplitude, duration, and rate. A mechanical device was used to apply a linear increase in thrust displacement or force and to control thrust duration. Under displacement control, neural responses during the HVLA-SM increased in a fashion graded with thrust amplitude. Under force control neural responses were similar regardless of the thrust amplitude. Decreasing thrust durations at all thrust amplitudes except the smallest thrust displacement had an overall significant effect on increasing muscle spindle activity during the HVLA-SMs. Under force control, spindle responses specifically and significantly increased between thrust durations of 75 and 150?ms suggesting the presence of a threshold value. Thrust velocities greater than 20-30?mm/s and thrust rates greater than 300?N/s tended to maximize the spindle responses. This study provides a basis for considering biomechanical characteristics of an HVLA-SM that should be measured and reported in clinical efficacy studies to help define effective clinical dosages.

Reed WR; Cao DY; Long CR; Kawchuk GN; Pickar JG

2013-01-01

77

Camshaft bearing arrangement  

Energy Technology Data Exchange (ETDEWEB)

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

Aoi, K.; Ozawa, T.

1986-06-10

78

MATERIALS PERFORMANCE TARGETED THRUST FY 2004 PROJECTS  

Energy Technology Data Exchange (ETDEWEB)

The Yucca Mountain site was recommended by the President to be a geological repository for commercial spent nuclear fuel and high-level radioactive waste. The multi-barrier approach was adopted for assessing and predicting system behavior, including both natural barriers and engineered barriers. A major component of the long-term strategy for safe disposal of nuclear waste is first to completely isolate the radionuclides in waste packages for long times and then to greatly retard the egress and transport of radionuclides from penetrated packages. The goal of the Materials Performance Targeted Thrust program is to further enhance the understanding of the role of engineered barriers in waste isolation. In addition, the Thrust will explore technical enhancements and seek to offer improvements in materials costs and reliability.

DOE

2005-09-13

79

MATERIALS PERFORMANCE TARGETED THRUST FY 2004 PROJECTS  

International Nuclear Information System (INIS)

The Yucca Mountain site was recommended by the President to be a geological repository for commercial spent nuclear fuel and high-level radioactive waste. The multi-barrier approach was adopted for assessing and predicting system behavior, including both natural barriers and engineered barriers. A major component of the long-term strategy for safe disposal of nuclear waste is first to completely isolate the radionuclides in waste packages for long times and then to greatly retard the egress and transport of radionuclides from penetrated packages. The goal of the Materials Performance Targeted Thrust program is to further enhance the understanding of the role of engineered barriers in waste isolation. In addition, the Thrust will explore technical enhancements and seek to offer improvements in materials costs and reliability

2005-01-01

80

NATURAL BARRIERS TARGETED THRUST FY 2004 PROJECTS  

Energy Technology Data Exchange (ETDEWEB)

This booklet contains project descriptions of work performed by the Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM), Office of Science and Technology and International's (OST&I) Natural Barriers Targeted Thrust during Fiscal Year (FY) 2004. The Natural Barriers Targeted Thrust is part of OST&I's Science and Technology Program which supports the OCRWM mission to manage and dispose of high-level radioactive waste and spent nuclear fuel in a manner that protects health, safety, and the environment; enhances national and energy security; and merits public confidence. In general, the projects described will continue beyond FY 2004 assuming that the technical work remains relevant to the proposed Yucca Mountain Repository and sufficient funding is made available to the Science and Technology Program.

NA

2005-07-27

 
 
 
 
81

Calculating Track Thrust with Track Functions  

CERN Document Server

In e+e- event shapes studies at LEP, two different measurements were sometimes performed: a "calorimetric" measurement using both charged and neutral particles, and a "track-based" measurement using just charged particles. Whereas calorimetric measurements are infrared and collinear safe and therefore calculable in perturbative QCD, track-based measurements necessarily depend on non-perturbative hadronization effects. On the other hand, track-based measurements typically have smaller experimental uncertainties. In this paper, we present the first calculation of the event shape track thrust and compare to measurements performed at ALEPH and DELPHI. This calculation is made possible through the recently developed formalism of track functions, which are non-perturbative objects describing how energetic partons fragment into charged hadrons. By incorporating track functions into soft-collinear effective theory, we calculate the distribution for track thrust with next-to-leading logarithmic resummation. Due to a p...

Chang, Hsi-Ming; Thaler, Jesse; Waalewijn, Wouter J

2013-01-01

82

Increasing turbine-generator efficiency through improved bearing design  

Energy Technology Data Exchange (ETDEWEB)

The proportion of power consumed in the journal and thrust bearings of large turbine-generators is approximately 0.5 percent in machines larger than 500 MWe. A substantial portion of the losses is the result of turbulence in the oil films due to the high Reynolds number caused by higher surface velocities and greater clearances. This paper describes some of the design approaches being studied which give promise of halving the journal bearing losses and more than halving the thrust bearing losses. Each design is optimized in terms of its load carrying efficiency (horsepower per 1000 lb load) for two typical large turbine-generator sizes. The economic impacts of these improvements are examined with respect both to operating costs and capital costs. 5 refs.

McCloskey, T.; Pinkus, O.; Wilcock, D.F.

1981-01-01

83

Test apparatus for measuring jet engine thrust  

Energy Technology Data Exchange (ETDEWEB)

This patent describes an apparatus for simultaneously measuring variables to calculate total thrust generated from a turbofan jet engine having a lengthwise axis and which is characterized by (1) a section for generating drive gases, (2) a fan section which rotates about the lengthwise axis in response to the drive gases and which includes (i) exterior blades which rotate with the fan section for generating a propelling force, and (ii) an outer cowling, and (3) an outlet section for exhausting the drive gases to the atmosphere to provide a further propelling force, the apparatus comprising: a. a cradle for supporting the engine; b. means for suspending the cradle from a support structure so as to permit movement of the cradle in the lengthwise direction; c. means for measuring a forward force generated by the drive gases which are exhausted to the atmosphere for calculating the nozzle gas thrust, the measuring means including load cell means which are connected between the support structure and the cradle; d. dynamometer means including a rotatable portion, for measuring a torque generated by the engine fan section for calculating the thrust output of the fan section; and e. drive gear means for connecting the dynamometer means to the engine fan section, the drive gear means including belt means which are removably connected to the fan section and to the rotatable portion of the dynamometer means so as to transmit a rotational force between the fan section and the dynamometer means.

Laskody, J.R.

1988-12-06

84

Ouachita Mountain thrust front: An integrated approach to prospect analysis in thrust belts  

Energy Technology Data Exchange (ETDEWEB)

The thrust front of the Ouachita Mountains in western Arkansas is defined by the prominent asymmetric Washburn anticline. Previously interpreted as a complexly thrust-faulted anticline, the feature has been reinterpreted as a delta or triangle structure based on integration of surface mapping from thematic mapper (TM) data with subsurface interpretation of seismic and well-log cross sections. The northern limb of the Washburn anticline consists of a relatively unfaulted steeply north-dipping sheet above a major north-dipping backthrust. The southern limb consists of several steeply south-dipping thrust sheets that form a duplex zone in the center of the delta structure. Seismic and well-log interpretations suggested the presence of the imbrication in the core of the structure, but poor seismic resolution within the structure made interpretation of the backthrust and duplex geometry difficult. Surface mapping from TM imagery indicates the presence of the backthrust and the extent and geometry of the delta structure. Thrust sheets and horses also crop out, and their geometry is a guide to interpretation of subsurface data sets. The new model of the Ouachita thrust front as a delta structure has aided in subsurface data analysis and has resulted in a better understanding of trap geometry and distribution. This study also demonstrates the application of detailed surface mapping from satellite remote-sensing data to prospect-scale analysis.

Dodge, R.L. (Hunt Oil Co., Dallas, TX (USA)); Keeling, M.A. (Exxon Co., U.S.A., Houston, TX (USA)); Cassiani, D. (Exxon Yemen Inc., Houston, TX (USA))

1990-05-01

85

Blowdown thrust force under pipe rupture accident. Pt. 1. Experimental evaluations of blowdown thrust force and decompression characteristics  

Energy Technology Data Exchange (ETDEWEB)

Blowdown thrust forces and decompression characteristics were evaluated concerning the jet discharge or pipe whip tests with a 4-inch or 6-inch diameter pipe under PWR LOCA or BWR LOCA conditions related to pipe rupture accidents in nuclear power plants. This paper presents experimental evaluations of time-dependent and maximum blowdown thrust forces, and evaluations of decompression characteristics under instantaneous pipe rupture conditions. The following items are discussed: the peak value of the blowdown thrust force, the jet thrust coefficient for the maximum blowdown thrust force, the pressure recovery after break, and the relationship between the pressure undershoot of the sudden decompression and the decompression rate.

Yano, T. (Japan Atomic Energy Research Inst., Tokai, Ibaraki. Dept. of Nuclear Safety Research)

1984-06-01

86

Polar Bear  

Science.gov (United States)

In this episode of the Podcast of Life, host Ari Daniel Shapiro relates two close calls with polar bears. Listen as Heather Cray recalls how, dumped by a storm on a small Arctic island without a shotgun, she got an unexpected wake-up call. And when researcher Steve Amstrup accidentally crashed through the roof of a polar bearâs den, no one could predict what happened next. Also included is a Learn More section that provides background information on the scientists recorded in the podcast, lessons, images, and cool facts.

2009-01-01

87

Thrust evaluation of magneto plasma sail that obtains an electromagnetic thrust from the solar wind  

International Nuclear Information System (INIS)

Magneto Plasma Sail (MPS) is a propulsion system used in space, which generates its force by the interaction between the solar wind and an inflated magnetic field via a plasma injection. The quantitative evaluation of the thrust increment generated by injecting a plasma jet with a ?in less than unity was conducted by three-dimensional hybrid particle-in-cell (PIC) simulations in an ion inertia scale. The injected plasma ?in is 0.02 and the ratio of Larmor radius of injected ion to the representative length of the magnetic field is 0.5 at the injection point. In this situation, the obtained thrust of the MPS is 1.6 mN compared with the 0.2 mN of the thrust obtained by the pure magnetic sail since the induced current region on magnetosphere expanded by the magnetic inflation. (author)

2011-01-01

88

Thrust control in supersonic flight by external burning  

Energy Technology Data Exchange (ETDEWEB)

Control of the thrust and thrust vector angle is difficult for reuseable space transportation systems, when SERN-nozzles are used. In this paper the influence of external burning of hydrogen on the thrust and on the thrust vector angle for the research configuration ELAC 1 is investigated. The Navier-Stokes equations for viscous, compressible, reactive flows are solved. The mixture composition is calculated with the assumption of chemical equilibrium. The conservation equations are discretized on blockstructured, curvilinear grids with second-order accuracy. The resulting system of linear algebraic equations is solved with an alternating line-relaxation method. Results are presented for a free stream Mach number of Ma{sub {infinity}}=3.8. The thrust and especially the thrust vector angle can markedly be improved. (orig.)

Kropp, M.; Henze, A. [Technische Hochschule Aachen (Germany). Lehrstuhl fuer Stroemungslehre und Aerodynamisches Inst.

1999-12-01

89

Optimization of transfers under constraints on the thrust direction: I  

Science.gov (United States)

Transfers with a low thrust are considered under constraints imposed on the thrust vector direction. These constraints can be caused by peculiarities of the attitude control system and the mode of stabilization of a spacecraft, and, in the general case, they are functions of the time and state vector. The constraints specified by equalities and inequalities are investigated. It is shown that the optimal thrust is directed along the projection of the Lawden’s primer vector onto the restricting set.

Sukhanov, A. A.; Prado, A. F. B. De A.

2007-10-01

90

Thrust vector control using electric actuation  

Energy Technology Data Exchange (ETDEWEB)

Presently, gimbaling of launch vehicle engines for thrust vector control is generally accomplished using a hydraulic system. In the case of the space shuttle solid rocket boosters and main engines, these systems are powered by hydrazine auxiliary power units. Use of electromechanical actuators would provide significant advantages in cost and maintenance. However, present energy source technologies such as batteries are heavy to the point of causing significant weight penalties. Utilizing capacitor technology developed by the Auburn University Space Power Institute in collaboration with the Auburn CCDS, Marshall Space Flight Center (MSFC) and Auburn are developing EMA system components with emphasis on high discharge rate energy sources compatible with space shuttle type thrust vector control requirements. Testing has been done at MSFC as part of EMA system tests with loads up to 66000 newtons for pulse times of several seconds. Results show such an approach to be feasible providing a potential for reduced weight and operations costs for new launch vehicles. {copyright} 1995 {ital American} {ital Institute} {ital of} {ital Physics}

Bechtel, R.T.; Hall, D.K. [Marshall Space Flight Center, Marshall Space Flight Center, Alabama 35812 (United States)

1995-01-25

91

Cretaceous biostratigraphy in the Wyoming thrust belt  

Energy Technology Data Exchange (ETDEWEB)

Biostratigraphy is essential to exploration for oil and gas in the Wyoming thrust belt because fossils provide a temporal framework for interpretation of events of faulting, erosion, sedimentation, and the development of hydrocarbon traps and migration pathways. In the Cretaceous section, fossils are especially useful for dating and correlating repetitive facies of different ages in structurally complex terrain. The biostratigraphic zonation for the region is based on megafossils (chiefly ammonites), which permit accurate dating and correlation of outcrop sections, and which have been calibrated with the radiometric time scale for the Western Interior. Molluscan and vertebrate zone fossils are difficult to obtain from the subsurface, however, and ammonities are restricted to rocks of margin origin. Palynomorphs (plant microfossils) have proven to be the most valuable fossils in investigations of stratigraphy and structures in the subsurface of the thrust belt because palynomorphs can be recovered from drill cuttings. Palynomorphs also are found in both marine and nonmarine rocks and can be used for correlation between facies. In this paper, stratigraphic ranges of selected Cretaceous marine and nonmarine palynomorphs in previously designated reference sections in Fossil Basin, Wyoming, are correlated with the occurrence of ammonities and other zone fossils in the same sections. These correlations can be related to known isotopic ages, and they contribute to the calibration of palynomorph ranges in the Cretaceous of the Western Interior.

Nichols, D.J. (U.S. Geological Survey, Denver, CO); Jacobson, S.R.

1982-07-01

92

Prototype ventricular assist device supported on magnetic bearings  

Energy Technology Data Exchange (ETDEWEB)

Mechanical artificial hearts are now expected to be used as assist or total replacements for failing human hearts, if a reliable, anatomically appropriate design is developed. Initially, ventricular assist or total replacement devices were pulsatile air driven units containing a flexing polymeric diaphragm and two valves for each ventricle. Many reliability problems were encountered. Recently, attention has been focused on axial or centrifugal continuous flow blood pumps. Magnetic bearings employed in such devices offer the advantages of no required lubrication and large operating clearances. This paper describes a prototype continuous flow pump supported in magnetic bearings. The pump performance was measured in a simulated adult human circulation system. It delivered 6 liters/min of flow at 100 mm Hg differential head operating at 2,400 rpm in water. The pump is totally magnetically supported in four magnetic bearings - two radial and two thrust. The geometry and other properties of the bearings are described. Bearing parameters such as load capacity, current gains, and open loop stiffness are discussed. Bearing coil currents were measured during operation in air and water. The rotor was operated in various orientations to determine the actuator current gains. These values were then used to estimate the radial and thrust forces acting on the rotor in both air and water.

Allaire, P.E.; Maslen, E.H. [Univ. of Virginia, Charlottesville, VA (United States); Kim, H.C.; Olsen, D.B.; Bearnson, G.D. [Univ. of Utah, Salt Lake City, UT (United States)

1995-12-31

93

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-01-01

94

Basement involved thrusts from Northwestern Maracaibo Basin  

Energy Technology Data Exchange (ETDEWEB)

The interpretation of seismic reflection profiles from northwestern Maracaibo Basin, north of the Palmar River, suggests a late Neogene age for all the structures located within the north-northeast trends of anticlinal belts. These folded structures appear to be ramp anticlines generated from basement involved thrusts. Such detachments are intercepted by conjugate systems of low-angle decollements decoupled from the thick shaly intervals of Cretaceous and Eocene age. The resulting configuration of these fault systems are related to a mechanic of deformation referred as [open quotes]fish tail[close quotes]. This structural style favors the superposition of structural traps at different levels. The superposed reservoirs from La Paz, Mara, Sibucara, Mara Oeste, and Ensenada among others constitute superb examples of this style of deformation. Similar anticlinal structures are also observed to the southeast of the Basin in the Ceuta-Tomoporo area.

Audemard, F. (Intevep, S.A., Caracas (Venezuela))

1993-02-01

95

Recent research and development of bearings for helium circulator  

International Nuclear Information System (INIS)

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

1987-12-02

96

Low thrust minimum-fuel orbital transfer: a homotopic approach  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We describe in this paper the study of an earth orbital transfer with a low thrust (typically electro-ionic) propulsion system. The objective is the maximization of the final mass, which leads to a discontinuous control with a huge number of thrust arcs. The resolution method is based on single shoo...

Haberkorn, Thomas; Martinon, Pierre; Gergaud, Joseph

97

Electronics Engineering Department Thrust Area report FY'84  

Energy Technology Data Exchange (ETDEWEB)

This report describes the work of the Electronics Engineering Department Thrust Areas for FY'84: diagnostics and microelectronic engineering; signal and control engineering; microwave and pulsed power engineering; computer-aided engineering; engineering modeling and simulation; and systems engineering. For each Thrust Area, an overview and a description of the goals and achievements of each project is provided.

Minichino, C.; Phelps, P.L. (eds.)

1984-01-01

98

Electronics Engineering Department Thrust Area report FY'84  

International Nuclear Information System (INIS)

This report describes the work of the Electronics Engineering Department Thrust Areas for FY'84: diagnostics and microelectronic engineering; signal and control engineering; microwave and pulsed power engineering; computer-aided engineering; engineering modeling and simulation; and systems engineering. For each Thrust Area, an overview and a description of the goals and achievements of each project is provided.

1984-01-01

99

Smoother thrust on multi-polar type linear DC motor  

Energy Technology Data Exchange (ETDEWEB)

A LDM has the merits of a high response and a direct linear motion. Therefore, a LDM is used widely in the fields of Factory Automation (FA). As compared with a mono-polar type Linear DC Motor (LDM), it is possible for a multi-polar type LDM to have a longer stroke and more thrust with thin shape. However, there are thrust ripple on multi-polar type one. In this paper, a design to prevent thrust ripple is discussed. In order to make a smoother thrust on multi-polar type LDM, the structure of the LDM is set as a 2-phase coil type. This paper clarifies that the thrust ripple of the LDM has the minimum value of 1.68%, the pole pitch of 15 mm, the coil width of 12 mm and the permanent magnet width of 10 mm.

Wakiwaka, H.; Senoh, S.; Yajima, H; Yamada, H. [Shinshu Univ., Wakasato, Nagano (Japan). Faculty of Engineering; Oda, J. [Ohkura Electric Co., Ltd., Shirako, Wakou (Japan)

1997-09-01

100

Tertiary structural evolution of the Gangdese thrust system southeastern Tibet  

Energy Technology Data Exchange (ETDEWEB)

Structural and thermochronological investigations of southern Tibet (Xizang) suggest that intracontinental thrusting has been the dominant cause for formation of thickened crust in the southernmost Tibetan plateau since late Oligocene. Two thrust systems are documented in this study: the north dipping Gangdese system (GTS) and the younger south dipping Renbu-Zedong system (RZT). West of Lhasa, the Gangdese thrust juxtaposes the Late Cretaceous forearc basin deposits of the Lhasa Block (the Xigaze Group) over the Tethyan sedimentary rocks of the Indian plate, whereas east of Lhasa, the fault juxtaposes the Late Cretaceous-Eocene, Andean-type arc (the Gangdese batholith) over Tethyan sedimentary rocks. Near Zedong, 150 km southeast of Lhasa, the Gangdese thrust is marked by a >200-m-thick mylonitic shear zone that consists of deformed granite and metasedimentary rocks. A major south dipping backthrust in the hanging wall of the Gangdese thrust puts the Xigaze Group over Tertiary conglomerates and the Gangdese plutonics north of Xigaze and west of Lhasa. A lower age bound for the Gangdese thrust of 18.3{+-}0.5 Ma is given by crosscutting relationships. The timing of slip on the Gangdese thrust is estimate to be 27-23 Ma from {sup 40}Ar/{sup 39}Ar thermochronology, and a displacement of at least 46{+-}9 km is indicated near Zedong. The age of the Gangdese thrust (GT) is consistent with an upper age limit of {approximately}24 Ma for the initiation of movement on the Main Central thrust. In places, the younger Renbu-Zedong fault is thrust over the trace of the GT, obscuring its exposure. The RZT appears to have been active at circa 18 Ma but had ceased movement by 8{+-}1 Ma. The suture between India and Asia has been complexely modified by development of the GTS, RZT, and, locally, strike-slip and normal fault systems. 64 refs., 14 figs., 2 tabs.

Yin, An; Harrison, M. [Univ. of California, Los Angeles, CA (United States); Ryerson, F.J. [Lawrence Livermore National Lab., CA (United States); Wenji, Chen [State Seismological Bureau, Beijing (China); Kidd, W.S.F. [State Univ. of New York, Albany, NY (United States); Copeland, P. [Univ. of Houston, TX (United States)

1994-09-10

 
 
 
 
101

Tertiary structural evolution of the Gangdese thrust system, southeastern Tibet  

Science.gov (United States)

Structural and thermochronological investigations of southern Tibet (Xizang) suggest that intracontinental thrusting has been the dominant cause for formation of thickened crust in the southernmost Tibetan plateau since late Oligocene. Two thrust systems are documented in this study: the north dipping Gangdese system (GTS) and the younger south dipping Renbu-Zedong (RZT). West of Lhasa, the Gangdese thrust juxtaposes the Late Cretaceous forearc basin deposits of the Lhasa Block (the Xigaze Group) over the Tethyan sedimentary rocks of the Indian plate, whereas east of Lhasa, the fault juxtaposes the Late Cretaceous-Eocene, Andean-type arc (the Gangdese batholith) over Tethyan sedimentary rocks. Near Zedong, 150 km southeast of Lhasa, the Gangdese thrust is marked by a greater than 200-m-thick mylonitic shear zone that consists of deformed granite and metasedimentary rocks. A major south dipping backthrust in the hanging wall of the Gangdese thrust puts the Xigaze Group over Tertiary conglomerates and the Gangdese plutonics north of Xigaze and west of Lhasa. A lower age bound for the Gangdese thrust of 18.3 +/- 0.5 Ma is given by crosscutting relationships. The timing of slip on the Gangdese thrust is estimated to be 27-23 Ma from Ar-40/Ar-39 thermochronology, and a displacement of at least 46 +/- 9 km is indicated near Zedong. The age of the Gangdese thrust (GT) is consistent with an upper age limit of approximately 24 Ma for the initiation of movement on the Main Central thrust. In places, the younger Renbu-Zedong fault is thrust over the trace of the GT, obscuring its exposure. The RZT appears to have been active at circa 18 Ma but had ceased movement by 8 +/- 1 Ma. The suture between India and Asia has been complexly modified by development of the GTS, RZT, and locally, strike-slip and normal fault systems.

Yin, An; Harrison, T. Mark; Ryerson, F. J.; Wenji, Chen; Kidd, W. S. F.; Copeland, Peter

1994-09-01

102

Passive magnetic bearing configurations  

Energy Technology Data Exchange (ETDEWEB)

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

Post, Richard F. (Walnut Creek, CA)

2011-01-25

103

Yakataga fold-and-thrust belt: Structural geometry and tectonic implications of a small continental collision zone  

Science.gov (United States)

Collision of the Yakutat terrane with southern Alaska created a collisional fold-and-thrust belt along the Pacific-North America plate boundary. This southerner fold-and-thrust belt formed within continental sedimentary rocks but with the seaward vergence and tectonic position typical of an accretionary wedge. Northward exposure of progressively older rocks reflects that the fold-and-thrust belt forms a southward-tapered orogenic wedge that increases northward in structural relief and depth of erosion. Narrow, sharp anticlines separate wider, flat-bottomed synclines. Relatively steep thrust faults commonly cut the forelimbs of anticlines. Fold shortening and fault displacement both generally increase northward, whereas fault dip generally decreases northward. The coal-bearing lower part of the sedimentary section serves as a detachment for both folds and thrust faults. The folded and faulted sedimentary section defines a regional south dip of about 8°. The structural relief combined with the low magnitude of shortening of the sedimentary section suggest that the underlying basement is structurally thickened. I propose a new interpretation in which this thickening was accommodated by a passive-roof duplex with basement horses that are separated from the overlying folded and thrust-faulted sedimentary cover by a roof thrust with a backthrust sense of motion. Basement horses are ˜7 km thick, based on the thickness between the inferred roof thrust and the top of the basement in offshore seismic reflection data. This thickness is consistent with the depth of the zone of seismicity onshore. The inferred zone of detachment and imbrication of basement corresponds with the area of surface exposure of the fold-and-thrust belt within the Yakutat terrane and with the Wrangell subduction zone and arc farther landward. By contrast, to the west, the crust of the Yakutat terrane has been carried down a subduction zone that extends far landward with a gentle dip, corresponding with a gap in arc magmatism, anomalous topography, and the rupture zone of the 1964 great southern Alaska earthquake. I suggest that, to the east, detachment and imbrication of basement combined with coupling in the fold-and-thrust belt allowed the delaminated dense mantle lithosphere to subduct with a steeper dip than to the west, where buoyant Yakutat terrane crust remains attached to the subducted lithosphere. According to this interpretation, the Wrangell subduction zone is lithosphere of the Yakutat terrane, not Pacific Ocean lithosphere subducted beneath the Yakutat terrane. The Pacific-North America plate boundary would be within the northern deformed part of the Yakutat terrane, not along the boundary between the undeformed southern part of the Yakutat terrane and oceanic crust of the Pacific Ocean. The plate boundary is an evolving zone of distributed deformation in which most of the convergent component has been accommodated within the fold-and-thrust belt south of the northern boundary of the Yakutat terrane, the Chugach-St. Elias thrust fault, and most of the right-lateral component likely has been accommodated on the Bagley Icefield fault just to the north.

Wallace, Wesley K.

104

Evaluation of thrust measurement techniques for dielectric barrier discharge actuators  

Energy Technology Data Exchange (ETDEWEB)

Despite its popularity in the recent literature, plasma actuators lack a consistent study to identify limitations, and remedy thereof, of various thrust measurement techniques. This paper focuses on comparing two different experimental techniques commonly used to measure the global, plasma-induced thrust. A force balance is used to make a direct measurement of the thrust produced, which is then compared with a control volume analysis on data obtained through particle image velocimetry. The local velocity measured by particle image velocimetry is also validated with a fine-tip pressure probe. For the direct thrust measurements, the effect of varying the actuator plate length upon which the induced flow acts is investigated. The results from these tests show that the length of the actuator plate is most influential at higher voltages with the measured thrust increasing as much as 20 % for a six times reduction in the length of the plate. For the indirect thrust measurement, the influence of the control volume size is analyzed. When the two methods are compared against each other, good agreement is found when the control volume size has a sufficient downstream extent. Also, the discharge length is optically measured using visible light emission. A linear correlation is found between the discharge length and the thrust measurements for the actuator configurations studied. Finally, the energy conversion efficiency curve for a representative actuator is also presented. (orig.)

Durscher, Ryan; Roy, Subrata [University of Florida, Applied Physics Research Group, Mechanical and Aerospace Engineering Department, Gainesville, FL (United States)

2012-10-15

105

Evaluation of thrust measurement techniques for dielectric barrier discharge actuators  

Science.gov (United States)

Despite its popularity in the recent literature, plasma actuators lack a consistent study to identify limitations, and remedy thereof, of various thrust measurement techniques. This paper focuses on comparing two different experimental techniques commonly used to measure the global, plasma-induced thrust. A force balance is used to make a direct measurement of the thrust produced, which is then compared with a control volume analysis on data obtained through particle image velocimetry. The local velocity measured by particle image velocimetry is also validated with a fine-tip pressure probe. For the direct thrust measurements, the effect of varying the actuator plate length upon which the induced flow acts is investigated. The results from these tests show that the length of the actuator plate is most influential at higher voltages with the measured thrust increasing as much as 20 % for a six times reduction in the length of the plate. For the indirect thrust measurement, the influence of the control volume size is analyzed. When the two methods are compared against each other, good agreement is found when the control volume size has a sufficient downstream extent. Also, the discharge length is optically measured using visible light emission. A linear correlation is found between the discharge length and the thrust measurements for the actuator configurations studied. Finally, the energy conversion efficiency curve for a representative actuator is also presented.

Durscher, Ryan; Roy, Subrata

2012-10-01

106

Mesa COM Mancais Aerostaticos Para Simulacao Em Um Grau de Liberdade de Sistemas de Controle de Atitude de Satelite Artificiais (Table with Aerostatic Bearings for Simulation in One Degree of Freedom Attitude Control Systems of Artificial Satellites).  

Science.gov (United States)

The design is presented of a table supported by thrust and journal aerostatic bearings, which were dimensioned for simulation of the attitude movement of artificial satellites. The most important parameters for this design and the construction problems ar...

L. V. C. Cardieri C. C. Tu A. Detoledofleury

1987-01-01

107

ALBANIA: Thrust and backthrust systems of external Albanides: Examples  

Energy Technology Data Exchange (ETDEWEB)

External Albanides have proved as an oil/gas province in a certain limited area. Better understanding of thrusting and backthrusting systems and how both systems work, could improve objectives for exploration beyond actual discoveries. Backthrusting is not seen any more typical for Cenozoic sediments, where buried front of thrust faulted belts are very active. Mesozoic rocks, that are dominated by westward thrust propagation are also affected by backthrusting, thus leaving more space for other units accommodation. New concepts postulated are based on Deep Holes, Seismic Data, Outcrops and Spot Imagery. Among onshore examples, some of them cross existing fields.

Bega, Z.; Janopulli, V. [OEMV Exploration, Tirana (Albania)

1995-08-01

108

Thrust Steering of a Gridded Ion Engine  

Science.gov (United States)

In any spacecraft installation of an ion propulsion system it is likely that there will be a need to alter the position of the thrust vector with respect to the centre of the vehicle, in order to minimise attitude and orbital perturbations during operation. Of most importance is the need to correct for the movements of the centre of mass of the spacecraft during operation. These movements are caused by the consumption of propellant, by the deployment and rotation of solar arrays, and by the varying radiation flux from the sun. As an example of the seriousness of this problem, the consumption due to this cause for an Intelsat VII class satellite with a lifetime of 15 years would be 26kg for an excursion of the centre of mass of just 1cm. As a consequence, large gimbal systems (approximately 10kg) are employed. Whilst these devices can perform perfectly well, they do represent a considerable mass overhead, amplify launch vibrations to the thrusters, as well as occupying a large volume, and presenting large cost (0.8Meuro) and additional reliability concerns. Consequently a method for providing direct vectoring of the ion beam has been developed using the technique of relative grid translation.

Jameson, P.

2004-10-01

109

Performance evaluation of half-wetted hydrodynamic bearings with DLC coated surfaces.  

Energy Technology Data Exchange (ETDEWEB)

In conventional liquid lubrication it is assumed that surfaces are fully wetted and no slip occurs between the fluid and the solid boundary. Under the 'no slip' condition the maximum shear gradient occurs at the fluid-surface interface. When one or both surfaces are non-wetted by the fluid, boundary slip can occur due to weak bonding between the fluid and the solid surface, which reduces shear stresses in the fluid adjacent to the non-wetted surface. A thrust bearing tribometer was used to compare the performance of 'no slip' hydrodynamic thrust bearings with bearings surfaces that were made to slip at the interface between the surface and fluid. Hydrophobic surfaces on both runner and bearing were achieved with the deposition of hydrogenated diamond like carbon (H-DLC) films, produced by plasma-enhanced CVD on titanium alloy surfaces. Hydrophilic surfaces were created through the surface modification of DLC. A mixtures of water and glycerol was used as the lubricant. The tests were conducted using different constant bearing gaps. The normal load and the torque or traction force between the rotating runner and hydrodynamic thrust bearing were measured with load cells. The experimental results confirmed that load support is still possible when surfaces are partially-wetted or nonwetted.

Eryilmaz, O.; Erdemir, A.; Energy Systems

2008-01-01

110

Optimization of transfers under constraints on the thrust direction: II  

Science.gov (United States)

This paper completes the study of optimal transfers with constraints imposed on the thrust vector direction that was opened by paper [1]. The linear inhomogeneous and homogeneous constraints on the thrust direction are considered (specified either by equalities or inequalities), as well as mixed constraints. Some examples of the constraints are presented. A modified method of the transporting trajectory is applied in order to find the optimal transfer under the linear constraints on the thrust direction. This method also gives the necessary condition for a transfer possibility at a given constraint on the thrust direction. A numerical example is considered, in which the propellant consumption is analyzed for the cases of transfers with and without constraints.

Sukhanov, A. A.; Prado, A. F. B. De A.

2008-02-01

111

Solid Rocket Booster Thrust Vector Control Subsystem Description.  

Science.gov (United States)

Major Solid Rocket Booster-Thrust Vector Control (SRB-TVC) subsystem components and subcomponents used in the Space Transportation System (STS) are identified. Simplified schematics, detailed schematics, figures, photographs, and data are included to acqu...

J. Redmon

1983-01-01

112

Thrust control in supersonic flight by external burning  

Energy Technology Data Exchange (ETDEWEB)

Control of the thrust and thrust vector angle is difficult for reuseable space transportation systems, when SERN-nozzles are used. In this paper the influence of external burning of hydrogen on the thrust and on the thrust vector angle for the research configuration ELAC 1 is investigated. The Navier-Stokes equations for viscous, compressible, reactive flows are solved. The mixture composition is calculated with the assumption of chemical equilibrium. The conservation equations are discretized on blockstructured, curvilinear grids with second-order accuracy. The resulting system of linear algebraic equations is solved with an alternating line-relaxation method. Results are presented for a free stream Mach number of Ma[sub [infinity

Kropp, M.; Henze, A. (Technische Hochschule Aachen (Germany). Lehrstuhl fuer Stroemungslehre und Aerodynamisches Inst.)

1999-01-01

113

Interrelations of mud volcanism, fluid venting, and thrust-anticline folding: Examples from the external northern Apennines (Emilia-Romagna, Italy)  

Science.gov (United States)

The present work aims to provide an example of connection between fluid seepage and fault/fracture zones associated with compressional thrust folds. Surface fluid seepage along the Pede-Apennine margin consists of mud volcanism and methane-rich emissions showing an intimate link with thrust-related folds. Dominant gaseous or CH4-bearing fluid emissions characterize thrust fold settings in which fluid escape from the main reservoir and source rock (i.e., the Marnoso Arenacea flysch) is not impeded by a seal layer. Conversely, remarkable mud volcanism is closely linked to the presence of the impermeable Ligurian units sealing the Marnoso Arenacea reservoir. Structural analyses focused on selected thrust folds exhibiting clear relations between surface seepage and brittle elements associated with the fold. Various scenarios potentially explaining mud volcanism and venting over the crestal region of the thrust-related folds are discussed with respect to fluid pressure state and the development of second-order fault and fracture sets that are observed to control surface fluid expulsion. It is proposed that mud volcanism can be potentially triggered by first-order fault failure cycles during which the overpressured fluid is released during faulting events. Past anomalous eruptions associated with strong earthquakes seem to support this hypothesis. The relatively quiescent but continuous activity of the current Pede-Apennine mud volcanoes could instead reflect a short-lived leakage of overpressured fluids along permeable fractures/faults. Expansion of methane contained in the rising mud may assist this process fundamentally.

Bonini, Marco

2007-08-01

114

Thrust enhancement of the gasdynamic mirror (GDM) fusion propulsion system  

Science.gov (United States)

The gasdynamic mirror propulsion system is a device that utilizes a magnetic mirror configuration to confine a hot plasma to allow fusion reactions to take place while ejecting a fraction of the energetic charged particles through one end to generate thrust. Because the fusion fuel is generally an isotope of hydrogen, e.g., deuterium or tritium, this propulsion device is capable of producing very large specific impulses (e.g., 200,000 seconds) but at modest thrusts. Since large thrusts are desirable, not only for reducing travel time but also for lifting sizable payloads, we have examined methods by which GDM's thrust could be enhanced. The first consists of utilizing the radiation generated by the plasma, namely bremsstrahlung and synchrotron radiation, to heat a hydrogen propellant which upon exhausting through a nozzle produces the additional thrust. We asses the performance in this case by using an ideal model that ignores heat transfer considerations of the chamber wall, and one that takes into account heat flow and wall temperature limitations. We find in the case of a DT burning plasma that although thrust enhancement is significant, it was more than offset by the large drop in the specific impulse and a concomitant increase in travel time. The second method consisted of not altering the original GDM operation, but simply increasing the density of the injected plasma to achieve higher thrust. It is shown that the latter approach is more effective since it is compatible with improved performance in that it reduces trip time but at the expense of larger vehicle mass. For a D-He3 burning device the use of hydrogen to enhance thrust appears to be more desirable since the radiated power that goes into heating the hydrogen propellant is quite large.

Kammash, Terry; Lee, Myoung-Jae; Poston, David I.

1997-01-01

115

Thrust enhancement of the gasdynamic mirror (GDM) fusion propulsion system  

International Nuclear Information System (INIS)

The gasdynamic mirror propulsion system is a device that utilizes a magnetic mirror configuration to confine a hot plasma to allow fusion reactions to take place while ejecting a fraction of the energetic charged particles through one end to generate thrust. Because the fusion fuel is generally an isotope of hydrogen, e.g., deuterium or tritium, this propulsion device is capable of producing very large specific impulses (e.g., 200,000 seconds) but at modest thrusts. Since large thrusts are desirable, not only for reducing travel time but also for lifting sizable payloads, we have examined methods by which GDM's thrust could be enhanced. The first consists of utilizing the radiation generated by the plasma, namely bremsstrahlung and synchrotron radiation, to heat a hydrogen propellant which upon exhausting through a nozzle produces the additional thrust. We asses the performance in this case by using an ideal model that ignores heat transfer considerations of the chamber wall, and one that takes into account heat flow and wall temperature limitations. We find in the case of a DT burning plasma that although thrust enhancement is significant, it was more than offset by the large drop in the specific impulse and a concomitant increase in travel time. The second method consisted of not altering the original GDM operation, but simply increasing the density of the injected plasma to achieve higher thrust. It is shown that the latter approach is more effective since it is compatible with improved performance in that it reduces trip time but at the expense of larger vehicle mass. For a D-He3 burning device the use of hydrogen to enhance thrust appears to be more desirable since the radiated power that goes into heating the hydrogen propellant is quite large.

1997-01-10

116

Thrust enhancement of the gasdynamic mirror (GDM) fusion propulsion system  

Energy Technology Data Exchange (ETDEWEB)

The gasdynamic mirror propulsion system is a device that utilizes a magnetic mirror configuration to confine a hot plasma to allow fusion reactions to take place while ejecting a fraction of the energetic charged particles through one end to generate thrust. Because the fusion fuel is generally an isotope of hydrogen, e.g., deuterium or tritium, this propulsion device is capable of producing very large specific impulses (e.g., 200,000 seconds) but at modest thrusts. Since large thrusts are desirable, not only for reducing travel time but also for lifting sizable payloads, we have examined methods by which GDM{close_quote}s thrust could be enhanced. The first consists of utilizing the radiation generated by the plasma, namely bremsstrahlung and synchrotron radiation, to heat a hydrogen propellant which upon exhausting through a nozzle produces the additional thrust. We asses the performance in this case by using an ideal model that ignores heat transfer considerations of the chamber wall, and one that takes into account heat flow and wall temperature limitations. We find in the case of a DT burning plasma that although thrust enhancement is significant, it was more than offset by the large drop in the specific impulse and a concomitant increase in travel time. The second method consisted of not altering the original GDM operation, but simply increasing the density of the injected plasma to achieve higher thrust. It is shown that the latter approach is more effective since it is compatible with improved performance in that it reduces trip time but at the expense of larger vehicle mass. For a D-He{sup 3} burning device the use of hydrogen to enhance thrust appears to be more desirable since the radiated power that goes into heating the hydrogen propellant is quite large. {copyright} {ital 1997 American Institute of Physics.}

Kammash, T.; Lee, M. [Department of Nuclear Engineering and Radiological Sciences The University of Michigan Ann Arbor, Michigan48109 (United States); Poston, D.I. [Los Alamos National Laboratory MS K-551 Los Alamos, New Mexico87545 (United States)

1997-01-01

117

Exploring fold and thrust belts in Google Earth  

Science.gov (United States)

Google Earth enhances traditional geologic maps by allowing the viewer to explore three-dimensional map patterns and the interaction between structure and topography in dictating those map patterns. This activity overlays 4, 7.5' USGS quadrangles on Google Earth terrain and imagery data and encourages students to investigate common features of fold-and-thrust belts. Keywords: Google Earth, fold-and-thrust belt, visualization

Loveless, Jack

118

Early use of thrust manipulation versus non-thrust manipulation: a randomized clinical trial.  

UK PubMed Central (United Kingdom)

The purpose of this study was to investigate the comparative effectiveness of early use of thrust (TM) and non-thrust manipulation (NTM) in sample of patients with mechanical low back pain (LBP). The randomized controlled trial included patients with mechanically reproducible LBP, ? age 18-years who were randomized into two treatment groups. The main outcome measures were the Oswestry Disability Index (ODI) and a Numeric Pain Rating Scale (NPRS), with secondary measures of Rate of Recovery, total visits and days in care, and the work subscale of the Fears Avoidance Beliefs Questionnaire work subscale (FABQ-w). A two-way mixed model MANCOVA was used to compare ODI and pain, at baseline, after visit 2, and at discharge and total visits, days in care, and rate of recovery (while controlling for patient expectations and clinical equipoise). A total of 149 subjects completed the trial and received care over an average of 35 days. There were no significant differences between TM and NTM at the second visit follow-up or at discharge with any of the outcomes categories. Personal equipoise was significantly associated with ODI and pain. The findings suggest that there is no difference between early use of TM or NTM, and secondarily, that personal equipoise affects study outcome. Within-groups changes were significant for both groups.

Cook C; Learman K; Showalter C; Kabbaz V; O'Halloran B

2013-06-01

119

Early use of thrust manipulation versus non-thrust manipulation: a randomized clinical trial.  

Science.gov (United States)

The purpose of this study was to investigate the comparative effectiveness of early use of thrust (TM) and non-thrust manipulation (NTM) in sample of patients with mechanical low back pain (LBP). The randomized controlled trial included patients with mechanically reproducible LBP, ? age 18-years who were randomized into two treatment groups. The main outcome measures were the Oswestry Disability Index (ODI) and a Numeric Pain Rating Scale (NPRS), with secondary measures of Rate of Recovery, total visits and days in care, and the work subscale of the Fears Avoidance Beliefs Questionnaire work subscale (FABQ-w). A two-way mixed model MANCOVA was used to compare ODI and pain, at baseline, after visit 2, and at discharge and total visits, days in care, and rate of recovery (while controlling for patient expectations and clinical equipoise). A total of 149 subjects completed the trial and received care over an average of 35 days. There were no significant differences between TM and NTM at the second visit follow-up or at discharge with any of the outcomes categories. Personal equipoise was significantly associated with ODI and pain. The findings suggest that there is no difference between early use of TM or NTM, and secondarily, that personal equipoise affects study outcome. Within-groups changes were significant for both groups. PMID:23040656

Cook, Chad; Learman, Kenneth; Showalter, Chris; Kabbaz, Vincent; O'Halloran, Bryan

2012-10-02

120

Methods for evaluating nontypical gate valve thrust requirements  

Energy Technology Data Exchange (ETDEWEB)

Evaluating rising stem wedge type gate valves is not a problem when the valves can be design-basis tested and their operability margins determined diagnostically. The problem occurs when they cannot be tested because of system limitations or when they can be tested only at some less-than-design-basis condition. To evaluate these valves requires various analytical methods by which the design-basis stem thrust requirement can be determined. This is typically done with valve stem thrust force models that are used to calculate the requirements or to extrapolate the results from less than a design-basis test. The stem thrust models used by the nuclear industry to determine the opening or closing stem thrust requirements for these gate valves have generally assumed that the highest load the valve experiences during closure (but before seating) is at flow isolation and during unwedging or before flow initiation in the opening direction. However, during full-scale valve testing conducted for the USNRC, several of the valves produced stem thrust histories that showed peak closing stem forces occurring before flow isolation in the closing direction and after flow initiation in the opening direction. All of the valves that exhibited this behavior in the closing direction also showed signs of internal damage. Initially, we dismissed the early peak in the closing stem thrust requirement as damage-induced and labeled it nonpredictable behavior.

Steele, R. Jr.; Watkins, J.C.; DeWall, K.G. [Idaho National Engineering Lab., Idaho Falls, ID (United States); Weidenhamer, G.H.

1994-10-01

 
 
 
 
121

Characterization of aircraft noise during thrust reverser engagement  

Science.gov (United States)

Airport noise impact on communities has been an area of considerable study. However, it has been determined that thrust reverser engagement is an area requiring further research. This paper presents findings on thrust reverser from a noise study done at Washington-Dulles International Airport (IAD) in October of 2004. Previous studies have found that high levels of acoustic energy in commercial aircraft during takeoff are contained below 300 Hz [Sharp, Ben H., Guovich, Yuri A., and Albee, William, W., ``Status of Low-Frequency Aircraft Noise Research and Mitigation,'' Wyle Report WR 01-21, San Francisco, September 2001]. Preliminary analysis of thrust reverser signatures indicates similar findings. A categorization of aircraft noise during thrust reverser engagement is given and looks at factors that may affect the noise characteristics. Some of these factors include: plane type, engine type, and thrust ratings. In addition, a brief analysis of frequency weightings of the Equivalent Sound Level (Leq) and Sound Exposure Level (SEL) metrics, and their application to thrust reverser noise is discussed. [Work supported by the Federal Aviation Administration.

Gutierrez, Remy M.; Atchley, Anthony A.; Hodgdon, Kathleen K.

2005-09-01

122

Thrust vector control of satellites using smart parallel manipulators  

Science.gov (United States)

This paper presents the concept, control strategy, and simulations of thrust vector control of satellites. First, an innovative thrust vector control concept is introduced, which utilizes the UHM multifunctional smart parallel manipulator to provide precision position control of the thruster vector and vibration suppression capability while the thruster fires. The configuration of the thrust vector control system is then illustrated, and the satellite attitude dynamic model is built. Third, the UHM smart parallel manipulator is introduced and its kinematics and controller design are discussed. The fuzzy logic controller is employed to precisely position the smart parallel manipulator and to compensate the non-linearities due to the friction and backlash of the actuators and the tolerance of the joints. Finally, the satellite attitude controller and the fuzzy logic controller are designed, and simulations are carried out to realize the thrust vector control of a satellite. The results indicate that the smart parallel manipulator can precisely achieve the thrust vector control, the misalignment of the trust vector of the satellite can be corrected effectively, and the position accuracy of the thrust vector is 0.68 arc minutes.

Ma, Kougen; Ghasemi-Nejhad, Mehrdad N.

2006-04-01

123

The technology of the bearings used in the nuclear power generation system turbine generator units  

International Nuclear Information System (INIS)

A bearing consists of all the stationary part which allow the relative motion in rotation or in translation, of a shaft line. Inside the bearing there is a journal bearing with a metallic anti-friction coating (the babbitt metal). The high power turbine generator unit rotors are supported by smooth transversal journal bearings fed with oil which fills the empty space and runs along the shaft. The technologies used for the bearings and the thrust bearings of the turbine generator units and the various shaft lines of the French CP0/CP1- and CP2/1300 MW-type nuclear power plants are described. The experience feedback is then discussed in terms of the dynamics of the shaft line, i.e. vibrational problems, the influence of the alignment and the babbitt metal incidents. (author)

1997-01-01

124

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

International Nuclear Information System (INIS)

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

2007-11-02

125

Bilateral and multiple cavitation sounds during upper cervical thrust manipulation  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The popping produced during high-velocity, low-amplitude (HVLA) thrust manipulation is a common sound; however to our knowledge, no study has previously investigated the location of cavitation sounds during manipulation of the upper cervical spine. The primary purpose was to determine which side of the spine cavitates during C1-2 rotatory HVLA thrust manipulation. Secondary aims were to calculate the average number of pops, the duration of upper cervical thrust manipulation, and the duration of a single cavitation. Methods Nineteen asymptomatic participants received two upper cervical thrust manipulations targeting the right and left C1-2 articulation, respectively. Skin mounted microphones were secured bilaterally over the transverse process of C1, and sound wave signals were recorded. Identification of the side, duration, and number of popping sounds were determined by simultaneous analysis of spectrograms with audio feedback using custom software developed in Matlab. Results Bilateral popping sounds were detected in 34 (91.9%) of 37 manipulations while unilateral popping sounds were detected in just 3 (8.1%) manipulations; that is, cavitation was significantly (P Conclusions Cavitation was significantly more likely to occur bilaterally than unilaterally during upper cervical HVLA thrust manipulation. Most subjects produced 3–4 pops during a single rotatory HVLA thrust manipulation targeting the right or left C1-2 articulation; therefore, practitioners of spinal manipulative therapy should expect multiple popping sounds when performing upper cervical thrust manipulation to the atlanto-axial joint. Furthermore, the traditional manual therapy approach of targeting a single ipsilateral or contralateral facet joint in the upper cervical spine may not be realistic.

Dunning James; Mourad Firas; Barbero Marco; Leoni Diego; Cescon Corrado; Butts Raymond

2013-01-01

126

Compliant Journal Bearings  

UK PubMed Central (United Kingdom)

IntroductionFor the nonlinear dynamic analysis of complex rotorsin ship propulsion systems and turbines, accuratemodels of the bearings are essential.In case of water-lubricated compliant journal bearings,common in marine technology practice, the classicimpedance method loses its validity.ObjectiveThe objective of this project is to develop a model ofa compliant journal bearing, where as a first step theinfinitely long bearing is considered.MethodsTheory Fig. 1 shows the geometry of a compliantjournal bearing. Most variables are nondimensional.journal center#Y##uXhR#bearing centerFigure 1: Compliant journal bearingThe film thickness is given byh=1-# X cos #-# Y sin #+uThe pressur

H. J. Van Leeuwen; D. H. Van Campen; M. J. W. Schouten

127

Geologic mapping delineates new thrust sheets, duplex structures, and timing relationships between the Meade and Crawford thrusts in Wyoming, Idaho, and Utah  

Energy Technology Data Exchange (ETDEWEB)

New geologic maps of nine complete and six partial 7.5[prime] quadrangles delineate a large-scale duplex comprised of at least five thrust sheets that together form the Sheep Creek culmination in the footwall of the Meade thrust. From west to east, the Sheep Creek culmination includes the Home Canyon, Sheep Creek, Red Mountain, northern Crawford, and Afton thrust sheets. The thrusts are floored by the regional sole decollement in the Cambrian Gros Ventre Formation and merge upward with a roof thrust that lies along the Meade thrust in the west and decollements in the Jurassic Gypsum Spring and Preuss salt intervals in the east. The individual thrusts of Sheep Creek culmination are generally blind thrusts that are recognized by integrating the surface mapping with subsurface well and seismic data in balanced cross sections. The common map expression for individual thrust sheets is marked by translated fault-propagation anticlines in upper Paleozoic, Triassic, and lower Jurassic rocks that are bordered to the east by frontal decollement fold trains in middle and upper Jurassic rocks. The Meade thrust is folded above the Sheep Creek culmination in the northern part of the map area, and it is specifically folded above the Crawford fault-propagation fold, Sublette anticline, north of the map area at Elk Valley, Idaho. Thus, the Meade and Crawford thrusts are not coeval, linked thrusts as previously assumed. Instead, the individual thrusts of Sheep Creek culmination form a linked, eastward-younging thrust system along which 30 km of Crawford thrust displacement in Utah is partitioned between the Sheep Creek, Red Mountain, northern Crawford, and Afton thrusts in Idaho and Wyoming.

Coogan, J.C.

1993-04-01

128

Wedge equilibrium in fold-and-thrust belts: prediction of out-of-sequence thrusting based on sandbox experiments and natural examples  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thrust tectonics are dealt with on the basis of primarily experiments focusing on the dynamics of a developing thrust belt and on understanding and predicting normal-sequence and out-of-sequence thrusting. Field examples are presented in addition to the examples of sandbox-model experiments. The res...

Nieuwland, D.A.; Leutscher, J.H.; Gast, J.

129

Bilateral and multiple cavitation sounds during upper cervical thrust manipulation.  

UK PubMed Central (United Kingdom)

BACKGROUND: The popping produced during high-velocity, low-amplitude (HVLA) thrust manipulation is a common sound; however to our knowledge, no study has previously investigated the location of cavitation sounds during manipulation of the upper cervical spine. The primary purpose was to determine which side of the spine cavitates during C1-2 rotatory HVLA thrust manipulation. Secondary aims were to calculate the average number of pops, the duration of upper cervical thrust manipulation, and the duration of a single cavitation. METHODS: Nineteen asymptomatic participants received two upper cervical thrust manipulations targeting the right and left C1-2 articulation, respectively. Skin mounted microphones were secured bilaterally over the transverse process of C1, and sound wave signals were recorded. Identification of the side, duration, and number of popping sounds were determined by simultaneous analysis of spectrograms with audio feedback using custom software developed in Matlab. RESULTS: Bilateral popping sounds were detected in 34 (91.9%) of 37 manipulations while unilateral popping sounds were detected in just 3 (8.1%) manipulations; that is, cavitation was significantly (P < 0.001) more likely to occur bilaterally than unilaterally. Of the 132 total cavitations, 72 occurred ipsilateral and 60 occurred contralateral to the targeted C1-2 articulation. In other words, cavitation was no more likely to occur on the ipsilateral than the contralateral side (P = 0.294). The mean number of pops per C1-2 rotatory HVLA thrust manipulation was 3.57 (95% CI: 3.19, 3.94) and the mean number of pops per subject following both right and left C1-2 thrust manipulations was 6.95 (95% CI: 6.11, 7.79). The mean duration of a single audible pop was 5.66 ms (95% CI: 5.36, 5.96) and the mean duration of a single manipulation was 96.95 ms (95% CI: 57.20, 136.71). CONCLUSIONS: Cavitation was significantly more likely to occur bilaterally than unilaterally during upper cervical HVLA thrust manipulation. Most subjects produced 3-4 pops during a single rotatory HVLA thrust manipulation targeting the right or left C1-2 articulation; therefore, practitioners of spinal manipulative therapy should expect multiple popping sounds when performing upper cervical thrust manipulation to the atlanto-axial joint. Furthermore, the traditional manual therapy approach of targeting a single ipsilateral or contralateral facet joint in the upper cervical spine may not be realistic.

Dunning J; Mourad F; Barbero M; Leoni D; Cescon C; Butts R

2013-01-01

130

Thrust faults in east-central New Mexico  

Energy Technology Data Exchange (ETDEWEB)

A belt of southeast-vergent thrust faults, at least 60 km long and 15 km wide, was recognized on seismic sections from central and northeastern Guadalupe County, New Mexico. These results are basement cored, and typically extend upward to approximately 500 m below the surface. Locally, the fault systems offset the Triassic uppermost sedimentary cover. Individual thrust slices generally average 7 km in width and commonly are bounded on the northwest by high-angle normal faults. Other manifestations of these features that affect the surface along strike include broad arching, low-amplitude folds and localized dissolution. The thrust belt is situated on the southeastern margin of the ancestral Sierra Grande arch, and is inferred to have resulted from reactivated structures. Because of their northeast-southwest orientation, the thrusts are also interpreted as products of early Laramide compression directed from the west. If so, the thrust are the most distant known to have been operating in the foreland region southeast of the Colorado Plateau microplate during this phase of deformation.

Maier, R.D. (Univ. of Texas, El Paso (USA))

1987-02-01

131

Engineering research, development and technology: Thrust area report FY 91  

International Nuclear Information System (INIS)

The mission of the Engineering Research, Development, and Technology Program at Lawrence, Livermore National Laboratory (LLNL) is to develop the technical staff and the technology needed to support current and future LLNL programs. To accomplish this mission, the Engineering Research, Development, and Technology Program has two important goals: (1) to identify key technologies and (2) conduct high quality work to enhance our capabilities in these key technologies. To help focus our efforts, we identify technology thrust areas and select technical leaders for each area. The thrust areas are integrated engineering activities and, rather than being based on individual disciplines, they are staffed by personnel from Electronics Engineering, Mechanical Engineering, and other LLNL organizations, as appropriate. The thrust area leaders are expected to establish strong links to LLNL program leaders and to industry; to use outside and inside experts to review the quality and direction of the work; to use university contacts to supplement and complement their efforts; and to be certain that we are not duplicating the work of others. The thrust area leader is also responsible for carrying out the work that follows from the Engineering Research, Development, and Technology Program so that the results can be applied as early as possible to the needs of LLNL programs. This annual report, organized by thrust area, describes activities conducted within the Program for the fiscal year, 1991. Its intent is to provide timely summaries of objectives, theories, methods, and results.

1991-01-01

132

Polar bears at risk  

Energy Technology Data Exchange (ETDEWEB)

Polar bears, the world's largest terrestrial carnivore, spend much of their lives on the arctic sea ice. This is where they hunt and move between feeding, denning, and resting areas. The world population, estimated at 22,000 bears, is made up of 20 relatively distinct populations varying in size from a few hundred to a few thousand animals. About 60 per cent of all polar bears are found in Canada. In general, the status of this species is stable, although there are pronounced differences between populations. Reductions in the extent and thickness of sea ice has lead the IUCN Polar Bear Specialist Group to describe climate change as one of the major threats facing polar bears today. Though the long-term effects of climate change will vary in different areas of the Arctic, impacts on the condition and reproductive success of polar bears and their prey are likely to be negative. Longer ice-free periods resulting from earlier break-up of sea ice in the spring and later formation in the fall is already impacting polar bears in the southern portions of their range. In Canada's Hudson Bay, for example, bears hunt on the ice through the winter and into early summer, after which the ice melts completely, forcing bears ashore to fast on stored fat until freeze-up in the fall. The time bears have on the ice to hunt and build up their body condition is cut short when the ice melts early. Studies from Hudson Bay show that for every week earlier that ice break-up occurs, bears will come ashore 10 kg lighter and in poorer condition. It is likely that populations of polar bears dividing their time between land and sea will be severely reduced and local extinctions may occur as greenhouse gas emissions continue to rise and sea ice melts. Expected changes in regional weather patterns will also impact polar bears. Rain in the late winter can cause maternity dens to collapse before females and cubs have departed, thus exposing occupants to the elements and to predators. Such rains also destroy the denning habitat of ringed seals, the polar bears' primary prey. Declines in the ringed seal population would mean a loss of food for polar bears. A trend toward stronger winds and increasing ice drift observed in some parts of the Arctic over the last five decades will likely increase energy expenditures and stress levels in polar bears that spend most of their lives on drifting sea ice. Polar bears face other limiting factors as well. Historically, the main threat to polar bears has been hunting. Satisfactory monitoring information has been obtained for most polar bear populations in recent years, however there is concern about hunting in areas without formal quota systems, such as Greenland. A range of toxic pollutants, including heavy metals, radioactivity, and persistent organic pollutants (POPs) are found throughout the Arctic. Of greatest concern are the effects of POPs on polar bears, which include a general weakening of the immune system, reduced reproductive success and physical deformities. The expansion of oil development in the Arctic poses additional threats; for example, disturbances to denning females in the Arctic National Wildlife Refuge in Alaska could undermine recruitment of the Beaufort Sea polar bear population. These threats, along with other effects of human activity in the Arctic, combine to pressure polar bears and their habitat. Large carnivores are sensitive indicators of ecosystem health and can be used to define the minimum area necessary to preserve intact ecosystems. WWF has identified the polar bear as a unique symbol of the complexities and interdependencies of the arctic marine ecosystem as it works toward its goal of preserving biodiversity for future generations.

Norris, S.; Rosentrater, L.; Eid, P.M. [WWF International Arctic Programme, Oslo (Norway)

2002-05-01

133

Improvement of hemocompatibility in centrifugal blood pump with hydrodynamic bearings and semi-open impeller: in vitro evaluation.  

UK PubMed Central (United Kingdom)

We have developed a noncontact-type centrifugal blood pump with hydrodynamic bearings and a semi-open impeller for mechanical circulatory assist. The impeller is levitated by an original spiral-groove thrust bearing and a herringbone-groove journal bearing, without any additional displacement-sensing module or additional complex control circuits. The pump was improved by optimizing the groove direction of the spiral-groove thrust bearing and the pull-up magnetic force between the rotor magnet and the stator coil against the impeller. To evaluate hemocompatibility, we conducted a levitation performance test and in vitro hemocompatibility tests by means of a mock-up circulation loop. In the hemolysis test, the normalized index of hemolysis was reduced from 0.721 to 0.0335 g/100 L corresponding to an expansion of the bearing gap from 1.1 to 56.1 microm. In the in vitro antithrombogenic test, blood pumps with a wide thrust bearing gap were effective in preventing thrombus formation. Through in vitro evaluation tests, we confirmed that hemocompatibility was improved by balancing the hydrodynamic fluid dynamics and magnetic forces.

Kosaka R; Maruyama O; Nishida M; Yada T; Saito S; Hirai S; Yamane T

2009-10-01

134

Improvement of hemocompatibility in centrifugal blood pump with hydrodynamic bearings and semi-open impeller: in vitro evaluation.  

Science.gov (United States)

We have developed a noncontact-type centrifugal blood pump with hydrodynamic bearings and a semi-open impeller for mechanical circulatory assist. The impeller is levitated by an original spiral-groove thrust bearing and a herringbone-groove journal bearing, without any additional displacement-sensing module or additional complex control circuits. The pump was improved by optimizing the groove direction of the spiral-groove thrust bearing and the pull-up magnetic force between the rotor magnet and the stator coil against the impeller. To evaluate hemocompatibility, we conducted a levitation performance test and in vitro hemocompatibility tests by means of a mock-up circulation loop. In the hemolysis test, the normalized index of hemolysis was reduced from 0.721 to 0.0335 g/100 L corresponding to an expansion of the bearing gap from 1.1 to 56.1 microm. In the in vitro antithrombogenic test, blood pumps with a wide thrust bearing gap were effective in preventing thrombus formation. Through in vitro evaluation tests, we confirmed that hemocompatibility was improved by balancing the hydrodynamic fluid dynamics and magnetic forces. PMID:19681836

Kosaka, Ryo; Maruyama, Osamu; Nishida, Masahiro; Yada, Toru; Saito, Sakae; Hirai, Shusaku; Yamane, Takashi

2009-07-22

135

Journal Bearing Dynamic Response.  

Science.gov (United States)

The response of a rigid-bearing, simple-rotor system subjected to an impact load applied to the rotor or pedestal support is analyzed. The problem assumes the bearing-rotor system to be initially under steady-state pressure conditions before the impact lo...

S. B. Malanoski D. E. Dougherty

1967-01-01

136

Low thrust hadron events with isolated ? or e from Petra  

International Nuclear Information System (INIS)

In search for new quark flavors, an excess of low thrust events containing muons is found for PETRA energies greater than 46.3 GeV. The muons in these events are quite isolated from hadronic energy as would be expected from pair production of massive quarks. Combining data from all 4 PETRA experiments, there are 14 events with thrust less than 0.8 and the cosine of the angle between the muons direction and the thrust axis less than 0.7. Based directly on measurements taken at lower energy, the expected number of evens is quite accurately predicted to be 2.4. The probability of a statistical fluctuation of this size or larger occurring in a given event selection is 3 x 10/sup -7/. Although these events are consistent with the production of a new quark flavor, the evidence is as yet insufficient to prove that this is the source. No excess of events is seen in the selection of low thrust events with isolated electrons where the sensitivity is substantially lower.

1987-01-01

137

Effect of quark masses on the perturbative thrust  

Energy Technology Data Exchange (ETDEWEB)

We study the effect of quark masses on the thrust to O(..cap alpha../sub s/) in QCD. We find the mass corrections to be significant and show that they reduce the estimated nonperturbative effects. They also allow realistic limits to be placed on the parameter ..lambda...

Basu, R.

1984-06-01

138

Engineering Research, Development and Technology, FY95: Thrust area report  

Energy Technology Data Exchange (ETDEWEB)

The mission of the Engineering Research, Development, and Technology Program at Lawrence Livermore National Laboratory (LLNL) is to develop the knowledge base, process technologies, specialized equipment, tools and facilities to support current and future LLNL programs. Engineering`s efforts are guided by a strategy that results in dual benefit: first, in support of Department of Energy missions, such as national security through nuclear deterrence; and second, in enhancing the nation`s economic competitiveness through their collaboration with US industry in pursuit of the most cost-effective engineering solutions to LLNL programs. To accomplish this mission, the Engineering Research, Development, and Technology Program has two important goals: (1) identify key technologies relevant to LLNL programs where they can establish unique competencies, and (2) conduct high-quality research and development to enhance their capabilities and establish themselves as the world leaders in these technologies. To focus Engineering`s efforts, technology thrust areas are identified and technical leaders are selected for each area. The thrust areas are comprised of integrated engineering activities, staffed by personnel from the nine electronics and mechanical engineering divisions, and from other LLNL organizations. This annual report, organized by thrust area, describes Engineering`s activities for fiscal year 1995. The report provides timely summaries of objectives methods, and key results from eight thrust areas: computational electronics and electromagnetics; computational mechanics; microtechnology; manufacturing technology; materials science and engineering; power conversion technologies; nondestructive evaluation; and information engineering.

NONE

1996-02-01

139

Precision Thrust Cumulant Moments at N^3LL  

CERN Multimedia

We consider cumulant moments (cumulants) of the thrust distribution using predictions of the full spectrum for thrust including O(alpha_s^3) fixed order results, resummation of singular N^3LL logarithmic contributions, and a class of leading power corrections in a renormalon-free scheme. From a global fit to the first thrust moment we extract the strong coupling and the leading power correction matrix element Omega_1. We obtain alpha_s(m_Z) = 0.1141 \\pm (0.0004)_exp \\pm (0.0014)_hadr \\pm (0.0007)_pert, where the 1-sigma uncertainties are experimental, from hadronization (related to Omega_1) and perturbative, respectively, and Omega_1 = 0.372 \\pm (0.044)_exp \\pm (0.039)_pert GeV. The n-th thrust cumulants for n > 1 are completely insensitive to Omega_1, and therefore a good instrument for extracting information on higher order power corrections, Omega'_n/Q^n, from moment data. We find (\\tilde Omega'_2)^(1/2) = 0.74 \\pm (0.11)_exp \\pm (0.09)_pert GeV.

Abbate, Riccardo; Hoang, Andre H; Mateu, Vicent; Stewart, Iain W

2012-01-01

140

Arcturus and the Bears  

Science.gov (United States)

Arcturus is the brightest star in Bootes. The ancient Greek name Arktouros means Bear Guard. The star, however, is not close to Ursa Maior (Big She-Bear) and Ursa Minor (Little She-Bear), as the name would suggest. This curious discrepancy could be explained by the star proper motion, assuming the name Bear Guard is a remote cultural heritage. The proper motion analysis could allow us to get an insight also into an ancient myth regarding Ursa Maior. Though we cannot explain scientifically such a myth, some interesting suggestions can be obtained about its possible origin, in the context of the present knowledge of the importance of the cult of the bear both during the Palaeolithic times and for several primitive populations of modern times, as shown by the ethnological studies.

Antonello, E.

2009-08-01

 
 
 
 
141

Different thrust belts and foredeeps in a global perspective  

Energy Technology Data Exchange (ETDEWEB)

Looking at tectonics from a global perspective may open new horizons in the structural studies of thrust belts as well as other tectonic settings. Inferences from plate motions over the past 40 m.y., based on structural data, indicate the presence of a coherent flow of plate motions. Moreover, a [open quotes]westward[close quotes] drift of the lithosphere relative to the asthenosphere is indicated by plate motions in the hot-spot reference frame. Independent geological observations such as the different styles of deformation in thrust belts associated with subduction following or opposing the relative [open quotes]eastward or northeastward[close quotes] mantle flow also support this global polarity, both in the general directions and in the [open quotes]westward[close quotes] component. Because of this, thrust belts related to east-northeast-dipping subduction show conspicuous structural and morphologic relief, involve deep crustal rocks, and are associated with shallow foredeeps. However, thrust belts related to west-dipping subduction show relatively low structural and morphological relief; they involve only shallow upper crustal rocks and are associated with deep foredeeps as well as back-arc extensions. In the case of west-dipping subduction, the area of the foredeep (filled or unfilled) is bigger than the area of the associated elevated orogene, and it is smaller in the opposite subduction. For this reason, in west-dipping subductions in the foredeep maintains longer conditions of deep sea facies with respect to the opposite end member. Foredeep depth in west-dipping subductions is controlled mainly by the rollback of the subduction hinge pushed by the relative [open quotes]eastward[close quotes] mantle flow, and foredeep depth in east- or northeast-dipping subductions is generated mainly by the load of the thrust sheets and by the rollback of the subduction hinge due to the advancing upper plate, contrasting the upward push of the mantle.

Doglioni, C. (Univ. of Bari (Italy))

1993-11-01

142

Performance of hybrid ball bearings in oil and jet fuel  

Energy Technology Data Exchange (ETDEWEB)

A 308-size hybrid ball bearing, with ceramic balls and steel rings, was tested using a diester oil and gas turbine fuel as lubricants at several speeds and loads. Heat generation data from this test work was then correlated with the heat generation model from a widely used computer code. The ability of this hybrid split inner ring bearing design to endure thrust reversals, which are expected in many turbine applications, was demonstrated. Finally, the bearing was successfully endurance tested in JP-10 fuel for 25 hours at 7560 N axial load and 36,000 rpm. This work has successfully demonstrated the technology necessary to use fuel-lubricated hybrid bearings in limited-life gas turbine engine applications such as missiles, drones, and other unmanned air vehicles (UAVs). In addition, it has provided guidance for use in designing such bearing systems. As a result, the benefits of removing the conventional oil lubricant system, i.e., design simplification and reduced maintenance, can be realized. 6 refs.

Schrader, S.M.; Pfaffenberger, E.E. (General Motors Corp., Allison Gas Turbine Div., Indianapolis, IN (United States))

1992-07-01

143

The Polar Bear Tracker  

Science.gov (United States)

This new Web site from the World Wildlife Fund (WWF) International explores how polar bears are affected by global warming. Data on the movements of two radio-collared bears can be viewed, along with the ice status, through a series of online maps. This is an interesting site with valuable information and a nice balance of maps, photos, and text. The animation of the polar bear tracking data is a really neat feature, but is best viewed by advancing through the stages manually because the rapid speed of the film makes it difficult to comprehend.

2002-01-01

144

Magnetic bearing update  

Energy Technology Data Exchange (ETDEWEB)

Stabilization of whirl instability by floppy, viscous bearing mounts is discussed and required material properties are estimated for the new tilt-whirl mode in eddy-current stabilized magnetic bearings. A relatively low Young`s modules Y {approximately} 10{sup 5} and high viscosity {zeta} {approximately} 10{sup 7} are required (both in MKS units), suggesting the need for careful mounting design. New information on periodic bearings shows that, thus far, Earshaw`s Theorem cannot be defeated by periodicity, despite the author`s earlier claims.

Fowler, T.K.

1995-05-25

145

Optimal synchronizability of bearings  

CERN Document Server

Bearings are mechanical dissipative systems that, when perturbed, relax toward a synchronized (bearing) state. Here we find that bearings can be perceived as physical realizations of complex networks of oscillators with asymmetrically weighted couplings. Accordingly, these networks can exhibit optimal synchronization properties through fine tuning of the local interaction strength as a function of node degree [Motter, Zhou, and Kurths, Phys. Rev. E 71, 016116 (2005)]. We show that, in analogy, the synchronizability of bearings can be maximized by counterbalancing the number of contacts and the inertia of their constituting rotor disks through the mass-radius relation, $m\\sim r^{\\alpha}$, with an optimal exponent $\\alpha=\\alpha_{\\times}$ which converges to unity for a large number of rotors. Under this condition, and regardless of the presence of a long-tailed distribution of disk radii composing the mechanical system, the average participation per disk is maximized and the energy dissipation rate is homogeneo...

Araújo, N A M; Baram, R M; Herrmann, H J; Andrade, J S

2013-01-01

146

Engineering research, development and technology. Thrust area report, FY93  

Energy Technology Data Exchange (ETDEWEB)

The mission of the Engineering Research, Development, and Technology Program at Lawrence Livermore National Laboratory (LLNL) is to develop the technical staff, tools, and facilities needed to support current and future LLNL programs. The efforts are guided by a dual-benefit research and development strategy that supports Department of Energy missions, such as national security through nuclear deterrence and economic competitiveness through partnerships with U.S. industry. This annual report, organized by thrust area, describes the activities for the fiscal year 1993. The report provides timely summaries of objectives, methods, and results from nine thrust areas for this fiscal year: Computational Electronics and Electromagnetics; Computational Mechanics; Diagnostics and Microelectronics; Fabrication Technology; Materials Science and Engineering; Power Conversion Technologies; Nondestructive Evaluation; Remote Sensing, Imaging, and Signal Engineering; and Emerging Technologies. Separate abstracts were prepared for 47 papers in this report.

1994-05-01

147

The Prevalence of Tongue Thrusting in Patients with Periodontal Disease  

Directory of Open Access Journals (Sweden)

Full Text Available Statement of Problem: Tongue thrust and/or its consequent swallowing pattern are amongst the parafunctional habits that have always been considered as etiological factors for dental disorders by different investigators.Purpose: The aim of this study was to investigate the prevalence of tongue thrusting and the incidence of periodontal disorders associated with this habit among patients referred to the Department of Periodontology, School of Dentistry, Tehran University of Medical Sciences.Material and Methods: Two hundred and eighty patients, undergoing first phase of periodontal therapy, were selected. Among them, those who had tongue thrusting were diagnosed and periodontal indices (probing depth, gingival recession, spacing and gingival enlargement) were measured. Also, crown-root ratio was assessed for each anterior tooth.Results: Tongue thrusting was seen in 27.3%of patients, whereas 29.8% and 33.8% of them showed an increase in periodontal pocket depths in their upper and lower jaws,respectively. Gingival recession was found in the upper jaw in 12.98% and in the lowerjaw in 49.35% of the cases. Crown to root length ratio in 24.6% of the upper incisors and 35.1% of the lower incisors were found to be higher than normal. Spacing was observed between the incisors in 31.2% and 41.6% of the patients in the upper and lower jaws, respectively. Finally 31.2% of the patients showed gingival enlargement.Conclusion: The results of the present study revealed a considerable increase in the prevalence of various periodontal diseases among these subjects. To minimize the clinical problems of such patients, prevention of periodontal diseases through excellent oral hygiene and regular dental visits are suggested.

S.A. Miremadi; A.A. Khoshkhounejad; E. Mahdavi

2005-01-01

148

Fracturing and brecciation along the Max Meadows thrust, southwestern Virginia  

Energy Technology Data Exchange (ETDEWEB)

Fracturing is an important mechanism of porosity development in deformed hydrocarbon provinces such as the Eastern Overthrust belt, but the sizes and shapes of fractured zones place critical constraints on exploration strategies. Fracturing and brecciation associated with the Max Meadows thrust, along which the Cambrian Rome Formation have been emplaced atop the younger Cambrian Elbrook and Conococheague Formations of the Pulaski thrust sheet, are controlled by lithology, proximity to the fault, and mesoscopic folding. Within the Max Meadows sheet, Rome carbonates are highly fractured and, in fold cores near the fault, brecciated. Rome mudstones and sandstones are tightly folded, and near the fault have developed both an incipient axial planar cleavage and a set of closely spaced fractures striking perpendicular to fold axes. In comparison, the wholly carbonate sequence of the Pulaski sheet had earlier been folded into a large syncline characterized by bedding-parallel shear in shaly and thin-bedded layers, flexural slip folding, and localized fracturing of thick layers. Thus breccia and fracture porosity zones in the study area are highly localized, of irregular geometry, and essentially restricted to the upper thrust sheet. Zones of tectonic breccia and fracture porosity are not attractive exploration targets, then, unless they occur as uniform and widespread broken zones in sedimentologically and mechanically homogeneous beds.

Haneberg, W.C.

1984-04-01

149

Paleogene thrust tectonics in northwestern Venezuela: Petroleum system implications  

Energy Technology Data Exchange (ETDEWEB)

Oil exploration in northeastern Perija Mountains, northwestern Maracaibo basin, has been difficult, mainly due to the various tectonic events that have strongly deformed this area. This study is an attempt at better understanding the effect of a Paleogene thrusting event on the petroleum system development in the area. Subsidence analysis interpretation at both sides of the NNE directed Tigre fault (which separates the northern Perija Mountains from the rest of the Maracaibo basin) suggests the onset of a foreland basin during, at least, Paleocene-Early Eocene time. Continuous sedimentation occurred from Late Cretaceous to Early Eocene, as long as it kept pace with subsidence, in the west block of the fault, while the east block acted as an obstacle against the thrust-sheet movement, delaying its subsidence. Sedimentation for this time is associated with a thick unit of mainly paralic sediments west of that fault and thinner continental (fluvial) to shallow marine sediments, with an intra-Paleocene/Early Eocene unconformity, east of it. So, this tectonic event, associated with convergence from the north, caused a south-verging thrust sheet giving rise to differences in the evolution of the petroleum system on both sides of the Tigre fault, mainly regarding the existence of source rocks and their generation/migration of hydrocarbons, preservation time and critical moment. Finally, in order to evaluate the oil exploration opportunities in northeastern Perija mountains, it is advisable that any integrated interpretation of the petroleum system processes (generation-migration-accumulation) take into account this tectonic event.

Quijada, E.; Oropeza, S. [Maraven, S.A., Caracas (Venezuela)

1996-08-01

150

Kinematic evolution of fold and thrust belts. Insights from experimental modeling  

International Nuclear Information System (INIS)

Physical experiments were performed to gain a better understanding on the kinematic evolution of fold and thrust belts. The present study focuses on deformation of sedimentary cover caused by thrust and reverse movements along the basement fault. Our physical models comprise dry quartz sand representing brittle sedimentary rock and viscous silicone polymer representing overpressured mudstone. Computerized X-ray tomography was applied to the experiments to analyze the kinematic evolution of fold and thrust belts. In the sand models, the width of deformation zone above thrust was wider than that above reverse fault, because back thrust developed on the hanging wall of reverse fault. Within the physical models composed of dry sand and silicone polymer, minor folds and thrusts with minor displacement developed on the footwall of the major monoclinal flexure. These results compare well with the geometry and kinematic evolution of the fold and thrust belts in Japan. (author)

2011-01-01

151

A study on the frictional characteristics of bearing materials for the main coolant pump in SMART  

International Nuclear Information System (INIS)

Experimental frictional and wear characteristics of silicon graphite materials lubricated with high temperature and highly pressurized water to use for the journal bearing and the thrust bearing in the main coolant pump bearing of SMART is studied in this paper. Similar operating condition of the bearings is realized in the tribometer, so the materials are lubricated with high temperature and highly pressurized water. Friction coefficient and wear loss are analyzed to choose the best silicon graphite material. Pin on plate test specimens are used and coned disk springs are used to control the applied force on the specimens. Wear loss and wear width are measured by an precision balance and a micrometer. The friction force is measured by the strain gauge which can be used under high temperature and high pressure. Three kinds of silicon graphite materials are examined and compared with each other, and each material shows similar but different results on frictional and wear characteristics.

2001-01-01

152

Climate Drives Polar Bear Origins  

Science.gov (United States)

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

153

Tribology of alternative bearings.  

Science.gov (United States)

The tribological performance and biological activity of the wear debris produced has been compared for highly cross-linked polyethylene, ceramic-on-ceramic, metal-on-metal, and modified metal bearings in a series of in vitro studies from a single laboratory. The functional lifetime demand of young and active patients is 10-fold greater than the estimated functional lifetime of traditional polyethylene. There is considerable interest in using larger diameter heads in these high demand patients. Highly cross-linked polyethylene show a four-fold reduction in functional biological activity. Ceramic-on-ceramic bearings have the lowest wear rates and least reactive wear debris. The functional biological activity is 20-fold lower than with highly cross-linked polyethylene. Hence, ceramic-on-ceramic bearings address the tribological lifetime demand of highly active patients. Metal-on-metal bearings have substantially lower wear rates than highly cross-linked polyethylene and wear decreases with head diameter. Bedding in wear is also lower with reduced radial clearance. Differential hardness ceramic-on-metal bearings and the application of ceramic-like coatings reduce metal wear and ion levels. PMID:17016223

Fisher, John; Jin, Zhongmin; Tipper, Joanne; Stone, Martin; Ingham, Eileen

2006-12-01

154

Tribology of alternative bearings.  

UK PubMed Central (United Kingdom)

The tribological performance and biological activity of the wear debris produced has been compared for highly cross-linked polyethylene, ceramic-on-ceramic, metal-on-metal, and modified metal bearings in a series of in vitro studies from a single laboratory. The functional lifetime demand of young and active patients is 10-fold greater than the estimated functional lifetime of traditional polyethylene. There is considerable interest in using larger diameter heads in these high demand patients. Highly cross-linked polyethylene show a four-fold reduction in functional biological activity. Ceramic-on-ceramic bearings have the lowest wear rates and least reactive wear debris. The functional biological activity is 20-fold lower than with highly cross-linked polyethylene. Hence, ceramic-on-ceramic bearings address the tribological lifetime demand of highly active patients. Metal-on-metal bearings have substantially lower wear rates than highly cross-linked polyethylene and wear decreases with head diameter. Bedding in wear is also lower with reduced radial clearance. Differential hardness ceramic-on-metal bearings and the application of ceramic-like coatings reduce metal wear and ion levels.

Fisher J; Jin Z; Tipper J; Stone M; Ingham E

2006-12-01

155

Uranium favorability of tertiary rocks in the Badger Flats, Elkhorn Thrust Area, Park and Teller Counties, Colorado  

International Nuclear Information System (INIS)

Uranium potential of Tertiary rocks in the Badger Flats--Elkhorn Thrust area of central Colorado is closely related to a widespread late Eocene erosion surface. Most uranium deposits in the area are in the Eocene Echo Park Alluvium and Oligocene Tallahassee Creek Conglomerate, which were deposited in paleodrainage channels on or above this surface. Arkosic detritus within the channels and overlying tuffaceous sedimentary rocks of the Antero and Florissant Formations of Oligocene age and silicic tuffs within the volcanic units provide abundant sources of uranium that could be concentrated in the channels where carbonaceous debris facilitates a reducing environment. Anomalous soil, water, and stream-sediment samples near the Elkhorn Thrust and in Antero basin overlie buried channels or are offset from them along structural trends; therefore, uranium-bearing ground water may have moved upward from buried uranium deposits along faults. The area covered by rocks younger than the late Eocene erosion surface, specifically the trends of mapped or inferred paleochannels filled with Echo Park Alluvium and Tallahassee Creek Conglomerate, and the Antero Formation are favorable for the occurrence of uranium deposits

1976-01-01

156

Kinematic structural restorations and discrete fracture modeling of a thrust trap: a case study from the Tarija Basin, Argentina  

Energy Technology Data Exchange (ETDEWEB)

The integration between kinematic structural restorations and discrete fracture simulation is applied to a thrusted and fractured fault block in the Tarija basin, Northern Argentina. The emphasis is on the influence of the factor time on the deformation history and fracture growth. The structural evolution of the gas bearing Santa Rosa reservoir forms the basis for understanding the development of the 3D fracture system, as simulated with 3D kinematic restorations. During the restoration, the cumulative dilatational strain was calculated and mapped and compared to traditional curvature analyses. The strain maps are subsequently used to simulate geologically realistic discrete fracture networks that form the basis for further exploration and development of the field. (author)

Sanders, C.; Bonora, M.; Richards, D. [Midland Valley Ltd., Glasgow (United Kingdom); Kozlowski, E.; Sylwan, C.; Cohen, M. [Pan American Energy, Buenos Aires (Argentina)

2004-08-01

157

Bearings for surgical instruments  

UK PubMed Central (United Kingdom)

A journal bearing for a high speed surgical drill and/or attachment for rotatably supporting a cutter is made from a polymer of polyimide resin and graphite material and is designed to have a polygon configured bore where there are two point contact of the mating surfaces of the bore walls and cutter's shaft and preferably the bore is square shaped in cross section. This bearing results in a decrease in the envelope size of the support tube and hence, the overall diameter of the surgical instrument at the distal end enhances the line of vision of the cutter to the surgeon when the surgeon is performing surgical procedures. The entrance ends of the intermediate bearings are countersunk to define a ramp to ease the egress of the tool bit shaft for entering the tube of the drill motor or drill attachment during the assembly thereof.

DEL RIO EDDY H; LAMANNA JOSE M; PERRY DOUGLAS A; ANSPACH THOMAS E; DEL RIO EDDY

158

Journal bearing simulator  

UK PubMed Central (United Kingdom)

A method and apparatus for measuring the load bearing capacity of engine oils under determined temperatures and shear rates. An eccentrically rotating cylindrical shaft (rotor) is used in a cylindrical journal bearing (stator) so arranged that the stator can be displaced from the centre of rotation by a known amount. Measurements are made of minimum gap between the rotor and stator and of the force required to maintain the eccentrically rotating loaded shaft at a position such that the oil in the gap between rotor and stator achieves a shear rate between 1 x 105 and 1 x 107 s-1, typically 1 x 106 s-1.

Bates Terence William

159

Structural analysis using thrust-fault hanging-wall sequence diagrams: Ogden duplex, Wasatch Range, Utah  

Energy Technology Data Exchange (ETDEWEB)

Detailed mapping and cross-section traverses provide the control for structural analysis and geometric modeling of the Ogden duplex, a complex thrust system exposed in the Wasatch Mountains, east of Ogden, Utah. The structures consist of east-dipping folded thrust faults, basement-cored horses, lateral ramps and folds, and tear faults. The sequence of thrusting determined by means of lateral overlap of horses, thrust-splay relationships, and a top-to-bottom piggyback development is Willard thrust, Ogden thrust, Weber thrust, and Taylor thrust. Major decollement zones occur in the Cambrian shales and limestones. The Tintic Quartzite is the marker for determining gross geometries of horses. This exposed duplex serves as a good model to illustrate the method of constructing a hanging-wall sequence diagram - a series of longitudinal cross sections that move forward in time and space, and show how a thrust system formed as it moved updip over various footwall ramps. A hanging wall sequence diagram also shows the complex lateral variations in a thrust system and helps to locate lateral ramps, lateral folds, tear faults, and other features not shown on dip-oriented cross sections. 8 figures.

Schirmer, T.W.

1988-05-01

160

Structural evidence for northeastward movement on the Chocolate Mountains thrust, southeasternmost Calfornia  

Energy Technology Data Exchange (ETDEWEB)

The Late Cretaceous Chocolate Mountains thrust of southeastern California and southwestern Arizona places a block of Proterozoic and Mesozoic continental crust over the late Mesozoic continental margin oceanic sedimentary and volcanic rocks of the regionally distinctive Orocopia Schist. The Chocolate Mountains thrust is interpreted as a thrust (burial, subduction) fault rather than a low-angle normal (exhumation, unroofing, uplift) fault. The Chocolate Mountains thrust zone contains sparse to locally abundant mesoscopic asymmetric folds. Fabric relations indicate that these folds are an integral part of and coeval with the thrust zone. On a lower hemisphere equal-area plot representing the orientation and sense of asymmetry of 80 thrust zone folds from 36 localities, spread over an area 60 by 10 km, Z folds plot northwest of and S folds plot southeast of a northeast-southwest striking vertical plane of overall monoclinic symmetry. The only sense of movement consistent with the collective asymmetry of the thrust zone folds is top to the northeast. Paleomagnetic data suggest that the original sense of thrusting, prior to Neogene vertical axis tectonic rotation related to the San Andreas fault system, was northward. The essential point is that movement of the upper plate of the Chocolate Mountains thrust evidently was continentward. Continentward thrusting suggests a tectonic scenario in which an insular or peninsular microcontinental fragment collided with mainland southern California. Alternative tectonic models involving subduction of the Orocopia Schist eastward beneath continental southern California circumvent the suture problem but are presently not supported by any direct structural evidence.

Dillon, J.T. (Alaska Div. of Geological and Geophysical Surveys, Fairbanks (USA)); Haxel, G.B. (Geological Survey, Flagstaff, AZ (USA)); Tosdal, R.M. (Geological Survey, Menlo Park, CA (USA))

1990-11-10

 
 
 
 
161

Reduction of Low-Thrust Continuous Controls for Trajectory Dynamics and Orbital Targeting  

Science.gov (United States)

A novel method to evaluate the trajectory dynamics of low-thrust spacecraft is developed. Using a two-body Newtonian model, the spacecraft thrust vector components are represented by Fourier series in terms of eccentric anomaly, and Gauss's variational equations are averaged over one orbit to obtain a set of secular equations. These secular equations are a function of 14 of the thrust Fourier coefficients, regardless of the order of the original Fourier series, and are sufficient to determine a low-thrust spiral trajectory with significantly reduced computational requirements as compared with integration of the full Newtonian problem. This method is applied to orbital targeting problems. The targeting problems are defined as two-point boundary value problems with fixed endpoint constraints. Average low-thrust controls that solve these problems are found using the averaged variational equations and a cost function represented also as a Fourier series. The resulting fuel costs and dynamic fidelity of the targeting solutions are evaluated. Low-thrust controls with equivalent average trajectory dynamics but different thrust profiles are also studied. Higher-order control coefficients that do not affect the average dynamics are used to reduce fuel costs and transform time-varying controls into controls with constant thrust arcs, which can be implemented more easily by low-thrust propulsion systems. These methods have applications to low-thrust mission design and space situational awareness. Example problems based on past missions and potential future scenarios demonstrate the effectiveness of these methods.

Hudson, Jennifer S.

162

Gravity sliding, thrusting, and petroleum traps in the Magdalena Basins and Cordillera Orientale, Colombia  

Energy Technology Data Exchange (ETDEWEB)

Major gravity slides on flanks of mountain belts can be misinterpreted as tectonic thrusts. They occur as synclines ([open quotes]fauteuils glisses[close quotes]) striking sub-parallel to dip slopes of major uplifts, overlie low-angle listric thrusts which pass upslope into listric or bedding-parallel normal faults, and may be associated with gravity-driven buried thrust fronts. The Nuevo Mondo syncline, underlain by the La Salinas thrust, and similar synclines along the east side of the Magdalena valley are interpreted as [open quotes]fauteuils glisses[close quotes], whose occurrence at the edge of the Cordillera Orientale creates an illusion of westward thrusting. Minor faults, formerly interpreted as east-dipping reverse faults along the west edge of the Cordillera Orientale are too small to have uplifted the Cordillera or to be correlatable with the major thrusts beneath synclines. They are reinterpreted as major west-dipping parallel faults, pass downslope westward beneath the synclines and/or into blind imbricate thrust structures. The Magdalena basins contain attractive east-verging tectonic thrust traps for hydrocarbons, and less attractive post-tectonic west-verging thrust traps formed by sliding down the east flank of the basin. Interpretation of these structures as post-deformational features allows modeling of the Cordillera Orientale as an overthrust sheet about 10 km thick that moved over 160 km southeastward. Its ramp underlies the east flank of the Magdalena basins. Its buried thrust front marks the edge of the Llanos basin.

Jones, P.B. (International Tectonic Consultants Ltd., Calgary, Alberta (Canada))

1993-02-01

163

Fault-related fluid flow, Beech Mountain thrust sheet, Blue Ridge Province, Tennessee-North Carolina  

Energy Technology Data Exchange (ETDEWEB)

The latest proterozoic Beech Granite is contained within the Beech Mountain thrust sheet (BMTS), part of a middle-late Paleozoic thrust complex located between Mountain City and Grandfather Mountain windows in the western Blue Ridge of TN-NC. At the base of the BMTS, Beech Granite is juxtaposed against lower Paleozoic carbonate and elastics of the Rome Fm. along the Stone Mountain thrust on the southeaster margin of the Mountain City window. At the top of the BMTS, Beech Granite occurs adjacent to Precambrian mafic rocks of the Pumpkin Patch thrust sheet (PPTS). The Beech Granite is foliated throughout the BMTS with mylonitization and localized cataclasis occurring within thrust zones along the upper and lower margins of the BMTS. Although the degree of mylonitization and cataclasis increases towards the thrusts, blocks of relatively undeformed granite also occur within these fault zones. Mylonites and thrusts are recognized as conduits for fluid movement, but the origin of the fluids and magnitude and effects of fluid migration are not well constrained. This study was undertaken to characterize fluid-rock interaction within the Beech Granite and BMTS. Extensive mobility of some elements/compounds within the thrust zones, and the isotopic and mineralogical differences between the thrust zones and interior of the BMTS indicate that fluid flow was focused within the thrust zones. The wide range of elevated temperatures (400--710 C) indicated by qz-fsp fractionations suggest isotopic disequilibrium. Using a more likely temperature range of 300--400 C for Alleghanian deformation, calculated fluid compositions indicate interactions with a mixture of meteoric-hydrothermal and metamorphic water with delta O-18 = 2.6--7.5[per thousand] for the upper thrust zone and 1.3 to 6.2[per thousand] for the lower thrust zone. These ranges are similar to isotopic data reported for other Blue Ridge thrusts and may represent later periods of meteoric water influx.

Waggoner, W.K.; Mora, C.I. (Univ. of Tennessee, Knoxville, TN (United States). Dept. of Geological Sciences)

1992-01-01

164

Hybrid superconductor magnet bearings  

Energy Technology Data Exchange (ETDEWEB)

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

Chu, W.

1995-04-01

165

Magnetically leviated superconducting bearing  

Energy Technology Data Exchange (ETDEWEB)

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.

Weinberger, Bernard R. (Avon, CT); Lynds, Jr., Lahmer (Glastonbury, CT)

1993-01-01

166

Amos Bear Gets Hurt.  

Science.gov (United States)

A three-day experiment set up by an early childhood teacher explored Piaget's view that children younger than age eight lack ability to take another's point of view. The experiment focused on a bear, the class mascot, and observations of children's empathetic behavior toward its "injury." Age-related differences in the children's responses were…

Read, Laurie

1995-01-01

167

Research at IMU: achievements, thrust areas and future challenges  

Directory of Open Access Journals (Sweden)

Full Text Available There have been significant achievements inresearch at IMU as indicated by the increasing amountof external funds obtained, and number of publicationsand postgraduate students produced since it startedits research activities in the year 2000. However, it isa great challenge indeed to ensure sustainability ofour research, which is currently heavily dependent oninternal funding. There is a need to realign our strategiesto further enhance our competitiveness in securingexternal funding for research. In line with this, theInstitute for Research, Development and Innovation(IRDI) was officially established on 18 September2012. The Institute will serve as a platform to supportall research activities at IMU. There are four Centresof Excellence based on the identified thrust areas underIRDI, namely 1) Centre for Bioactive Molecules andDrug Discovery; 2) Centre for Environmental andPopulation Health; 3) Centre for Cancer and StemCell Research, and 4) Centre for Health ProfessionalEducation Research. Major findings based on research inthese four thrust areas are reviewed in this paper. Withthe strategic planning and establishment of IRDI, it isour aspiration to bring research at IMU to a higher level.

Wan-Loy Chu

2013-01-01

168

Preloading of the thrust phase in cross-country skiing.  

UK PubMed Central (United Kingdom)

Based on the assumption that the stretch-shortening cycle is a natural way of muscle function, the occurrence of such a cycle was investigated in a diagonal technique of cross-country skiing. Cinematographic, special force platform, and telemetered EMG techniques were employed. The four subjects studied were all elite international level cross-country skiers, and the measurements were taken either under world championship conditions (cinematography) or during special test situations outdoors (EMG, force platform, and cinematography). The skiing was performed on the fixed uphill course (competition) and on the variable uphill tracks (2.5 degrees-11 degrees). The latter condition allowed mounting of a special long force platform system under the track. The results indicated that the leg kick phase is preceded by a typical unweighting phase, which is followed by braking and propulsion phases. Angular velocity curves of the hip, knee, and ankle joints revealed indirectly the segmental occurrence of the stretch-shortening cycle. Similar phenomena could be identified for the elbow joint during the pole plant and thrust phases. On a steep uphill track, the muscle activation pattern and the ground reaction forces resembled in many instances those of slow level running. Based on the results, a model was suggested to describe how the preloading of the leg thrust phase takes place as a sequential flow from one joint to another.

Komi PV; Norman RW

1987-03-01

169

Attitude control of a spinning rocket via thrust vectoring  

Energy Technology Data Exchange (ETDEWEB)

Two controllers are developed to provide attitude control of a spinning rocket that has a thrust vectoring capability. The first controller has a single-input/single-output design that ignores the gyroscopic coupling between the control channels. The second controller has a multi-input/multi-output structure that is specifically intended to account for the gyroscopic coupling effects. A performance comparison between the two approached is conducted for a range of roll rates. Each controller is tested for the ability to track step commands, and for the amount of coupling impurity. Both controllers are developed via a linear-quadratic-regulator synthesis procedure, which is motivated by the multi-input/multi-output nature of second controller. Time responses and a singular value analysis are used to evaluate controller performance. This paper describes the development and comparison of two controllers that are designed to provide attitude control of a spinning rocket that is equipped with thrust vector control. 12 refs., 13 figs., 2 tabs.

White, J.E.

1990-12-19

170

Precision electromagnetic calibration technique for micro-Newton thrust stands.  

UK PubMed Central (United Kingdom)

This paper introduces a new direct non-contact electromagnetic calibration technique for high precision measurements of micro-thrust and impulse. A ring-shaped electromagnet with an air gap is used in the calibration. The calibration force is produced by the interaction of a uniform magnetic field with a copper wire current in the air gap. This force depends linearly on this current as well as the steady angular displacement of the torsion arm of the thrust stand. The range of calibration force is very large and the calibration force is easy to generate and insensitive to the arm displacement. The calibration uncertainty for a 150-?N force is 4.17 ?N. The more influential factor on the calibration uncertainty is the magnetization of the electromagnet core due to the copper wire current. In the impulse calibration, the exerted impulse is linearly dependent on the maximal angular displacement of the torsion arm. The uncertainty in the impulse calibration is determined by uncertainties in both the force calibration and the pulse time.

He Z; Wu J; Zhang D; Lu G; Liu Z; Zhang R

2013-05-01

171

Compact and High Thrust Air Turbo Ram Engine  

Science.gov (United States)

The Air Turbo Ramjet (ATR) is a combined cycle engine which performs like a turbojet engine at subsonic speeds and a ramjet at supersonic speeds and therefore the ATR is an attractive propulsion system for the wide operation range (e.g. Mach 0 to Mach 4). The ATR can provide a higher specific impulse than a solid fuel rocket engine and a higher thrust per frontal area than a turbojet engine. The major ATR components are the inlet, fan (compressor), turbine, gas generator, combustor and exhaust nozzle. In the ATR, the turbine drive gas is generated by a decomposed liquid or solid fuel gas generator. In order to carry heavier payloads and to attain shorter flight time, the compact and high thrust engine is required. In this study, the ram combustor with the double-staged flameholders and the fan with tandem blade were introduced to shorten the engine length and to increase the fan pressure ratio, respectively. Furthermore, the engine testing was carried out on sea level static condition to confirm the engine component integration technologies for the ATR propulsion system.

Hasegawa, Hiroaki; Kitahara, Kazuki; Inukai, Yasuo

172

Solutions to near surface effects in mountainous thrust areas  

Energy Technology Data Exchange (ETDEWEB)

The oil and gas industry has continually made great efforts to enhance the quality of seismic data, either through improved acquisition techniques or more proficient processing algorithms. Moreover, quality requires processing geophysicists to select the appropriate tools to handle difficult situations: seismic in mountain thrust areas is a typical one. Fortunately, experienced people armed with leading edge technology can face the challenge. This paper investigates a few special techniques aimed at processing areas with extremely rough topography, the success of which always depends upon a multifold approach: extensive use of static techniques, implementation of a 3D floating datum plane, and 3D attribute dependent surface consistent techniques, such as offset and azimuth, which are appropriate in resolving residual statics. Mountainous areas often show complex geological features, such as fault planes and thrusting. Imaging is therefore another key issue. In order to facilitate it, advanced techniques, such as the perfected DMO algorithm that was designed to deal with rough surfaces, and wave equation datuming offer ideal solutions. Finally, it is possible to concentrate on imaging for which steep dip migration algorithms -- with the zero velocity layer -- have become routine.

Rodriguez, S.; Vuillermoz, C. [CGG, Houston, TX (United States)

1994-12-31

173

Particle migration through sealed bearings  

Energy Technology Data Exchange (ETDEWEB)

Tests were performed to determine the ability of various types of shielded bearings to isolate particulate from a clean environment in support of the Direct Optical Initiation (DOI) program. In the DOI firing system, a stronglink mechanism will share the same environment with a high-powered laser which needs uncontaminated optics to perform properly. Two commercially available shielded and sealed bearings were tested along with a sealed bearing designed at Allied Signal Inc., Kansas City Division (KCD). The KCD-designed bearing proved to be the best barrier, but the torque required to function the bearing was magnitudes above the commercial bearings. The commercial sealed bearing was an effective barrier, allowing a small fraction of particles to migrate through, and had a relatively low running torque. The shielded bearing was not acceptable as a particle barrier.

Sundvold, P.D.

1993-08-01

174

Development of a two-dimensional dual pendulum thrust stand for Hall thrusters.  

UK PubMed Central (United Kingdom)

A two-dimensional dual pendulum thrust stand was developed to measure thrust vectors [axial and horizontal (transverse) direction thrusts] of a Hall thruster. A thruster with a steering mechanism is mounted on the inner pendulum, and thrust is measured from the displacement between inner and outer pendulums, by which a thermal drift effect is canceled out. Two crossover knife-edges support each pendulum arm: one is set on the other at a right angle. They enable the pendulums to swing in two directions. Thrust calibration using a pulley and weight system showed that the measurement errors were less than 0.25 mN (1.4%) in the main thrust direction and 0.09 mN (1.4%) in its transverse direction. The thrust angle of the thrust vector was measured with the stand using the thruster. Consequently, a vector deviation from the main thrust direction of +/-2.3 degrees was measured with the error of +/-0.2 degrees under the typical operating conditions for the thruster.

Nagao N; Yokota S; Komurasaki K; Arakawa Y

2007-11-01

175

Control techniques of thrust vector for magnetic nozzle in laser fusion rocket  

Energy Technology Data Exchange (ETDEWEB)

An analysis of plasma behavior in a magnetic nozzle would be very useful for designing plasma propulsion systems using a laser fusion. We examine by using a three-dimensional (3D) hybrid code how a thrust vector varies with changing positions of the fusion explosion (off-axis explosion) for the one-coil system of a laser fusion rocket. Furthermore, we investigate plasma behaviors and the thrust efficiency, and optimize the thrust efficiency by changing the current and the position of a rear coil for two-coil system. We also discuss the possibility of control techniques of the thrust vector for a two-coil system.

Kajimura, Yoshihiro [Department of Advanced Energy Engineering Science, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University (Japan)]. E-mail: kajimura@aees.kyushu-u.ac.jp; Kawabuchi, Ryo [Department of Advanced Energy Engineering Science, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University (Japan); Nakashima, Hideki [Department of Advanced Energy Engineering Science, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University (Japan)

2006-11-15

176

Development of a two-dimensional dual pendulum thrust stand for Hall thrusters  

Science.gov (United States)

A two-dimensional dual pendulum thrust stand was developed to measure thrust vectors [axial and horizontal (transverse) direction thrusts] of a Hall thruster. A thruster with a steering mechanism is mounted on the inner pendulum, and thrust is measured from the displacement between inner and outer pendulums, by which a thermal drift effect is canceled out. Two crossover knife-edges support each pendulum arm: one is set on the other at a right angle. They enable the pendulums to swing in two directions. Thrust calibration using a pulley and weight system showed that the measurement errors were less than 0.25 mN (1.4%) in the main thrust direction and 0.09 mN (1.4%) in its transverse direction. The thrust angle of the thrust vector was measured with the stand using the thruster. Consequently, a vector deviation from the main thrust direction of +/-2.3° was measured with the error of +/-0.2° under the typical operating conditions for the thruster.

Nagao, N.; Yokota, S.; Komurasaki, K.; Arakawa, Y.

2007-11-01

177

Control techniques of thrust vector for magnetic nozzle in laser fusion rocket  

International Nuclear Information System (INIS)

An analysis of plasma behavior in a magnetic nozzle would be very useful for designing plasma propulsion systems using a laser fusion. We examine by using a three-dimensional (3D) hybrid code how a thrust vector varies with changing positions of the fusion explosion (off-axis explosion) for the one-coil system of a laser fusion rocket. Furthermore, we investigate plasma behaviors and the thrust efficiency, and optimize the thrust efficiency by changing the current and the position of a rear coil for two-coil system. We also discuss the possibility of control techniques of the thrust vector for a two-coil system.

2006-01-01

178

Thrust Ripples Reduction for a Vector Controlled Permanent Magnet Linear Synchronous Motor with IMC Controller  

Directory of Open Access Journals (Sweden)

Full Text Available The significant drawback of PMLSM is thrust ripples, which is mainly generated by the detent force caused by the interaction of the permanent magnet and iron core without input current in armature winding. It is the function of mover position relative to the stator. This will deteriorate the performance of the drive system in high precision applications. This paper focus on the thrust ripples reduction. To minimize the thrust ripples and realize the high-precision control, the components of thrust ripples are extracted first and then compensate with PI and IMC (Internal Model Control) controller

RAMESH BABU.DEVA; ARUNDHATI.B; ALICE MARY.K

2013-01-01

179

Experimental data analysis during rolling of corrosion resistant steel using hydraulic thrust  

Energy Technology Data Exchange (ETDEWEB)

Efficiency of a system for controlling band thickness in two regimes (in the regime of maintenance of constant force on thrust screws and in the regime of maintenance of constant liquid pressure in hydraulic cylinder of thrust device) was examined and its effectiveness during test rolling of bands of 12Kh18N10T steel was evaluated. The efficiency of the system for controlling band thickness using hydraulic thrust cylinders of back-up rolls in the regime of maintenance of constant force on thrust screws was confirmed.

Tret' yakov, A.V.; Migacheva, G.N.; Osadchij, A.Kh.; Kozlov, A.N.; Aleksandrov, V.K.

1982-07-01

180

The Tripoli-Roum thrust: source of the Beirut 551~AD earthquake and cause of the rise of Mount-Lebanon  

Science.gov (United States)

Mount-Lebanon stands out as the highest (3000m a.s.l.) mountain along the Eastern Mediterranean shore. This is the consequence of regional shortening induced by a 30\\textsuperscript{o} clockwise bend along the left-lateral Levant transform fault. The southern anset of this bend roughly coincides with the splitting of the Dead Sea Fault into three main strands: the Roum, Yammouneh, and Rachaya-Serghaya faults, all predominantly left-lateral. The uplift of Mount Lebanon appears to result from motion on a deep crustal thrust, whose trace stretches from Qubayat and Tripoli in the North to the Roum fault in the South, which acts as a lateral thrust ramp. The Tripoli-Roum Thrust (TRT) underlies the major coastal cities of Lebanon. It has never been identified, because it runs mostly offshore. We have found and studied features attesting to very young uplift and folding along the coast, especially in the Tripoli region. The prominent 70 m high cliff that cuts across the city of Tripoli appears to correspond to the cumulative scarp of the TRT, that lifts up fluvial conglomerates deposited by the Abou Ali and Abou Halqua rivers. Three anticlines (the Tourbol, Qualhat and Miniara) bearing evidence of young warping, with several levels of tilted terraces, mostly of marine origin, are aligned along the trace of the TRT, above the thrust ramp. At the eastern end of the Tourbol anticline, a clear example of recent river capture is found. We show that the Bared River was recently captured by the Abou Moussa River. The capture, and the 90\\textsuperscript{o} bend in the Abou Moussa River course, are probably due to the growth of the Tourbol anticline. North of Tripoli, the fault trace crosses the ancient city of Arqua, where historical documents and archeological excavations yield evidence of sudden destruction, possibly due to seismic slip on the fault. We infer the crescent-shape TRT thrust to have been the source of large historical earthquakes (551 and 1063 AD events for instance, the first of which destroyed Beirut and Tripoli). The thrust is the main feature that absorbs the partitioned dip slip component along the Lebanese compressive bend. We are currently trying to quantify and date the deformations and therefore to determine uplift rates.

Elias, A.; Tapponnier, P.; Daëron, M.; Jacques, E.; Sursock, A.; King, G.

2001-12-01

 
 
 
 
181

Delayed child-bearing.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To provide an overview of delayed child-bearing and to describe the implications for women and health care providers. OPTIONS: Delayed child-bearing, which has increased greatly in recent decades, is associated with an increased risk of infertility, pregnancy complications, and adverse pregnancy outcome. This guideline provides information that will optimize the counselling and care of Canadian women with respect to their reproductive choices. OUTCOMES: Maternal age is the most important determinant of fertility, and obstetric and perinatal risks increase with maternal age. Many women are unaware of the success rates or limitations of assisted reproductive technology and of the increased medical risks of delayed child-bearing, including multiple births, preterm delivery, stillbirth, and Caesarean section. This guideline provides a framework to address these issues. EVIDENCE: Studies published between 2000 and August 2010 were retrieved through searches of PubMed and the Cochrane Library using appropriate key words (delayed child-bearing, deferred pregnancy, maternal age, assisted reproductive technology, infertility, and multiple births) and MeSH terms (maternal age, reproductive behaviour, fertility). The Internet was also searched using similar key words, and national and international medical specialty societies were searched for clinical practice guidelines and position statements. Data were extracted based on the aims, sample, authors, year, and results. VALUES: The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). SPONSOR: The Society of Obstetricians and Gynaecologists of Canada. RECOMMENDATIONS 1. Women who delay child-bearing are at increased risk of infertility. Prospective parents, especially women, should know that their fecundity and fertility begin to decline significantly after 32 years of age. Prospective parents should know that assisted reproductive technologies cannot guarantee a live birth or completely compensate for age-related decline in fertility. (II-2A) 2. A fertility evaluation should be initiated after 6 months of unprotected intercourse without conception in women 35 to 37 years of age, and earlier in women > 37 years of age. (II-2A) 3. Prospective parents should be informed that semen quality and male fertility deteriorate with advancing age and that the risk of genetic disorders in offspring increases. (II-2A) 4. Women ? 35 years of age should be offered screening for fetal aneuploidy and undergo a detailed second trimester ultrasound examination to look for significant fetal birth defects (particularly cardiac defects). (II-1A) 5. Delayed child-bearing is associated with increased obstetrical and perinatal complications. Care providers need to be aware of these complications and adjust obstetrical management protocols to ensure optimal maternal and perinatal outcomes. (II-2A) 6. All adults of reproductive age should be aware of the obstetrical and perinatal risks of advanced maternal age so they can make informed decisions about the timing of child-bearing. (II-2A) 7. Strategies to improve informed decision-making by prospective parents should be designed, implemented, and evaluated. These strategies should provide opportunity for adults to understand the potential medical, social, and economic consequences of child-bearing throughout the reproductive years. (III-B) 8. Barriers to healthy reproduction, including workplace policies, should be reviewed to optimize the likelihood of healthy pregnancies. (III-C).

Johnson JA; Tough S

2012-01-01

182

The Polar Bear Game  

Science.gov (United States)

In this game, which is similar to Petals Around the Rose (cataloged separately), a player rolls 5 dice and asks the participants, âHow many polar bears are around the ice holes?â The participants try to figure out the riddle (rules of the game) by studying the dice arrangements and the answers that correspond. This webpage extends the game to have players also determine the number of fish and plankton.

2010-10-24

183

Was Himalayan normal faulting triggered by initiation of the Ramgarh-Munsiari thrust and development of the Lesser Himalayan duplex?  

Science.gov (United States)

The Ramgarh-Munsiari thrust is a major orogen-scale fault that extends for more than 1,500 km along strike in the Himalayan fold-thrust belt. The fault can be traced along the Himalayan arc from Himachal Pradesh, India, in the west to eastern Bhutan. The fault is located within the Lesser Himalayan tectonostratigraphic zone, and it translated Paleoproterozoic Lesser Himalayan rocks more than 100 km toward the foreland. The Ramgarh-Munsiari thrust is always located in the proximal footwall of the Main Central thrust. Northern exposures (toward the hinterland) of the thrust sheet occur in the footwall of the Main Central thrust at the base of the high Himalaya, and southern exposures (toward the foreland) occur between the Main Boundary thrust and Greater Himalayan klippen. Although the metamorphic grade of rocks within the Ramgarh-Munsiari thrust sheet is not significantly different from that of Greater Himalayan rock in the hanging wall of the overlying Main Central thrust sheet, the tectonostratigraphic origin of the two different thrust sheets is markedly different. The Ramgarh-Munsiari thrust became active in early Miocene time and acted as the roof thrust for a duplex system within Lesser Himalayan rocks. The process of slip transfer from the Main Central thrust to the Ramgarh-Munsiari thrust in early Miocene time and subsequent development of the Lesser Himalayan duplex may have played a role in triggering normal faulting along the South Tibetan Detachment system.

Robinson, Delores M.; Pearson, Ofori N.

2013-04-01

184

Highly integrated magnetic bearings  

Energy Technology Data Exchange (ETDEWEB)

Active Magnetic Bearings (AMB) have many advantages, compared to other bearing concepts. However, for many potential applications they are still too complicated and too expensive. In this paper the authors will present a new concept for active magnetic bearings with smaller dimensions, lower power consumption, and lower cost. To achieve this goal the system has been optimized in an overall mechatronic design. This led to new concepts for rotor, magnets, electronics and control. A single chip computer is used to reduce the number of electronic components. The switches of the voltage controlled power amplifier are driven directly by the PWM-unit of the single chip computer. Additionally, also the frequency inverter for the motor is driven directly by the PWM-unit. This leads to a minimum number of electronic components including the emergency power supply provided through energy recovered by the inverter. For development, calibration and error diagnostics a powerful serial link to a PC has been implemented. It works at a speed of 57.6 kBit/s and realizes a direct interface to MATLAB. This new configuration has been successfully applied to a small rotor system spinning at 60,000 rpm.

Buehler, P.; Siegwart, R. [ETH-Center, Zurich (Switzerland); Herzog, R. [Mecos Traxler AG, Winterthur (Switzerland)

1995-12-31

185

The technology of the bearings used in the nuclear power generation system turbine generator units; Technologie des paliers equipant les groupes turbo-alternateurs du parc nucleaire  

Energy Technology Data Exchange (ETDEWEB)

A bearing consists of all the stationary part which allow the relative motion in rotation or in translation, of a shaft line. Inside the bearing there is a journal bearing with a metallic anti-friction coating (the babbitt metal). The high power turbine generator unit rotors are supported by smooth transversal journal bearings fed with oil which fills the empty space and runs along the shaft. The technologies used for the bearings and the thrust bearings of the turbine generator units and the various shaft lines of the French CP0/CP1- and CP2/1300 MW-type nuclear power plants are described. The experience feedback is then discussed in terms of the dynamics of the shaft line, i.e. vibrational problems, the influence of the alignment and the babbitt metal incidents. (author) 4 refs., 11 figs.

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

1997-01-01

186

Improvement of azimuthal homogeneity in permanent-magnet bearing rotors  

Energy Technology Data Exchange (ETDEWEB)

Permanent magnets that are levitated and rotating over a bulk high-temperature superconductor (HTS) form the basis of many superconducting bearing designs. Experiments have shown that the rotational-loss``coefficient of friction`` for thrust bearings of this type can be as low as 8 {times} 10{sup {minus}6}. While the loss mechanisms of such bearings are not well understood, the azimuthal homogeneity of the rotating permanent magnet is believed to play an important role in determining the loss. One possible loss mechanism is magnetic hysteresis in the HTS, where the energy loss E per cycle is derived from the critical state model and given by E = K ({Delta}B{sup 3}/J{sub c}) where K is a geometric coefficient, {Delta}B is the variation in magnetic field at the surface of the HTS experienced during a rotation of the levitated magnet, and J{sub c} is the critical current density of the HTS. It is clear that a small decrease in {Delta}B (i.e., decreasing the azimuthal inhomogeneity of the rotating magnetic field) could have profound effects on decreasing E and the rotational coefficient of friction. The role of {Delta}B is also expected to be significant in reducing losses from eddy currents and other mechanisms. Low rotational losses in HTS bearings have been demonstrated only for levitated masses of several grams. For practical bearings, it is important to obtain these low losses with larger levitated masses. There are two main routes toward decreasing {Delta}B. The first is to improve the alignment of the magnetic particles during fabrication and to maintain close tolerances on grinding angles during manufacture of the permanent magnet. The second, the subject of this paper, is to provide correctional procedures after the magnet is fabricated.

Hull, J.R.; Rossing, T.D.; Mulcahy, T.M.; Uherka, K.L.

1992-10-23

187

Improvement of azimuthal homogeneity in permanent-magnet bearing rotors  

Energy Technology Data Exchange (ETDEWEB)

Permanent magnets that are levitated and rotating over a bulk high-temperature superconductor (HTS) form the basis of many superconducting bearing designs. Experiments have shown that the rotational-loss coefficient of friction'' for thrust bearings of this type can be as low as 8 [times] 10[sup [minus]6]. While the loss mechanisms of such bearings are not well understood, the azimuthal homogeneity of the rotating permanent magnet is believed to play an important role in determining the loss. One possible loss mechanism is magnetic hysteresis in the HTS, where the energy loss E per cycle is derived from the critical state model and given by E = K ([Delta]B[sup 3]/J[sub c]) where K is a geometric coefficient, [Delta]B is the variation in magnetic field at the surface of the HTS experienced during a rotation of the levitated magnet, and J[sub c] is the critical current density of the HTS. It is clear that a small decrease in [Delta]B (i.e., decreasing the azimuthal inhomogeneity of the rotating magnetic field) could have profound effects on decreasing E and the rotational coefficient of friction. The role of [Delta]B is also expected to be significant in reducing losses from eddy currents and other mechanisms. Low rotational losses in HTS bearings have been demonstrated only for levitated masses of several grams. For practical bearings, it is important to obtain these low losses with larger levitated masses. There are two main routes toward decreasing [Delta]B. The first is to improve the alignment of the magnetic particles during fabrication and to maintain close tolerances on grinding angles during manufacture of the permanent magnet. The second, the subject of this paper, is to provide correctional procedures after the magnet is fabricated.

Hull, J.R.; Rossing, T.D.; Mulcahy, T.M.; Uherka, K.L.

1992-10-23

188

Lithospheric Scale Deformation in Mega-thrust Subduction Zones  

Science.gov (United States)

Although the general plate tectonic model of subduction zone deformation and its relationship to the earthquake cycle for mega-thrust earthquakes is well known, there is neither consistency in such descriptions nor compatibility among seismological, geodetic, and geologic frameworks for such events. In particular in most seismologic studies of mega-thrust earthquakes there is an implicit assumption that the co-seismic slip is essentially symmetric across the fault surface - that is both the upper and lower plates moved equal amounts (but in opposite directions) during the rupture. Implicit in many geologic studies along convergent margins is the assumption that most permanent deformation is within the upper plate and the subducting slab basically transits the seismogenic zone with little permanent deformation. This perspective serves as the framework for many animations of subduction zone tectonics. Two subduction zone locales, the Kuriles and Solomon Islands, that have hosted recent Mw 8+ earthquakes demonstrate two end-member styles of subduction zone processes neither consistent with the conventional view. The November 2006 (thrust) and January 2007 (normal) earthquake pair in the Kuriles provide an opportunity to quantify the deformation within the subducting Pacific slab during the interseismic period. Based on the correspondence in slip during these events, we are able to both estimate the deformation (dominantly in the subducting slab and not in the overriding plate) and place a constraint on the static frictional strength of the megathrust interface of approximately 2-5 MPa. The 2007 Solomon Island Mw 8+ earthquake shows a distinctly different pattern of interseismic deformation. During this event, the propagating rupture traversed an active transform plate boundary between the separately subducting Australia and Solomon Sea plates. We interpret this to represent a situation in which interseismic deformation is primarily in the upper (Pacific) plate allowing the rupture to jump the fundamental barrier of a plate boundary. This is also compatible with limited GPS data available for the Australia plate near the trench indicating unimpeded subduction of Australia and thus little internal deformation of the subducting slab. These two subduction regimes indicate that there is likely a full continuum in how deformation is accommodated during subduction, and implies that attempts to determine the megathrust (and associated tsunami) potential of subduction zones using observations of upper-plate deformation is problematic.

Furlong, K. P.; Ammon, C.; Lay, T.

2008-12-01

189

Paleoseismic investigations at the Cal thrust fault, Mendoza, Argentina  

Science.gov (United States)

Along the active mountain front of the Andean Precordillera between 30°S and 34°S in western Argentina several earthquakes occurred in recent times, including a 7.0 Ms event in 1861 which destroyed the city of Mendoza and killed two thirds of its population. The 1861 event and two other earthquakes (Ms = 5.7 in 1929 and Ms = 5.6 in 1967) were generated on the Cal thrust fault, which extends over a distance of 31 km north-south and runs straight through the center of Mendoza. In the city, which has now more than 1 million inhabitants, the fault forms a 3-m-high fault scarp. Although the Cal thrust fault poses a serious seismic hazard, the paleoseismologic history of this fault and its long-term slip rate remains largely unknown (Mingorance, 2006). We present the first results of an ongoing paleoseismologic study of the Cal thrust at a site located 5 km north of Mendoza. Here, the fault offsets Late Holocene alluvial fan sediments by 2.5 m vertically and exhibits a well developed fault scarp. A 15-m-long and 2-3-m-deep trench across the scarp reveals three east-vergent folds that we interpret to have formed during three earthquakes. Successive retrodeformation of the two youngest folds suggests that the most recent event (presumably the 1861 earthquake) caused ~1.1 m of vertical offset and ~1.8 m of horizontal shortening. For the penultimate event we obtain a vertical offset of ~0.7 m and a horizontal shortening of ~1.9 m. A vertical displacement of ~0.7 m observed on a steeply west-dipping fault may be associated with an older event. The cumulative vertical offset of 2.5 m for the three inferred events is in excellent agreement with the height of the scarp. Based on the retrodeformation of the trench deposits the fault plane dips ~25° to the west. In the deepest part of the trench evidence for even older seismic events is preserved beneath an angular unconformity that was formed during a period of erosion and pre-dates the present-day scarp. Dating of samples to determine the recurrence interval of these seismic events and the long-term slip rate of the fault is in progress. References Mingorance, F. (2006): Morfometría de la escarpa de falla historica identificada al norte del cerro La Cal, zona de falla La Cal, Mendoza. Revista de la Asociación Geológica Argentina, 61 (4), 620-638.

Salomon, Eric; Schmidt, Silke; Hetzel, Ralf; Mingorance, Francisco

2010-05-01

190

Bearing for liquid metal pump  

Energy Technology Data Exchange (ETDEWEB)

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

Dickinson, Robert J. (Shaler Township, Allegheny County, PA); Wasko, John (Plum Borough, PA); Pennell, William E. (Unity Township, Allegheny County, PA)

1984-01-01

191

YBCO texturation and applications of superconducting magnetic bearings in flywheels for energy storage  

International Nuclear Information System (INIS)

A thrust bearing has been built consisting of 6 melt-textured YBCO pellets (diameter 30 x 18 mm) and a Nd-Fe-B ring magnet. The maximum levitation force of the bearing was 65 N at zero gap. Vertical stiffness at 1 mm gap was 440 N/cm, lateral stiffness was 130 N/cm. The bearing has been integrated into a flywheel system rotating a 2.8 kg disk at speeds up to 15 000 rpm. The maximum energy capacity was 4.8 Wh. It can be expected that further refinement of this technology should allow the operation of superconducting flywheels in the kWh range. (orig.).

1993-01-01

192

Palinspastic reconstruction of the Alpine thrust belt at the Alpine-Carpathian transition - A geological Sudoku  

Science.gov (United States)

The palinspastic reconstruction of the Austroalpine thrust belt is part of the project Karpatian Tectonics, which is funded by OMV Austria. The objective is to reconstruct the evolution of the thrust belt through the Early to Middle Miocene in order to obtain information on the palaeogeographic position of the Northern Calcareous Alps (NCA) in the region of the present Vienna Basin. A particular goal of the study is to constrain the position of reservoir rocks within the Rhenodanubic Flysch units and the NCA with respect to the autochthonous Malmian source rocks overlying the European basement below the Alpine-Carpathian thrust wedge, and to constrain the burial history of these source rocks. Reconstruction uses regional 2D seismic lines crossing from the European foreland into the fold-thrust belt, 3D seismic data covering the external thrust sheets, and lithostratigraphic data from a total of 51 selected wells, which were drilled and provided by OMV Austria. The main criterion, whether a well was suitable for palinspastic reconstruction or not, was its penetration of Alpine thrust sheets down to the Autochthonous Molasse of the foreland. Additional wells, which do not penetrate the entire Alpine thrust complex but include the Allochthonous Molasse or the external Alpine-Carpathian nappes (Waschberg and Roseldorf thrust unit, Rhenodanubic Flysch nappes) in their well path, were also taken into account. The well data in particular comprise stratigraphic information on the youngest overthrust sediments of the different thrust units and the underlying Autochthonous foreland Molasse. These data allow constraining the timing of thrust events in the allochthonous thrust units and overthrusting of the Autochthonous Molasse. In the particular case of overthrust Autochthonous Molasse, additionally to the timing of overthrusting, which can be derived from the youngest overthrust sediments, the palaeogeographic position of the Alpine Carpathian thrust front could directly be inferred from well data for the specific time period. By further utilization of geological maps, geological cross sections and two regional c. 80 km long composite 2D seismic sections through the external Alpine thrusts, the positions of major thrusts could be approximated for five time slices. This procedure was applied for the front of the allochthonous Molasse units, the floor thrust of the Roseldorf thrust unit, the Waschberg thrust unit and the frontal thrusts of the Rhenodanubic Flysch and the NCA. In addition, several out-of-sequence thrusts within the Waschberg unit, the Molasse unit, the Rhenodanubic Flysch and the Calcareous Alps (floor thrust of the NCA and two internal thrusts) were taken into account. The reconstruction results in 5 palinspastic maps for the time slices early Egerian (25 Ma), early Eggenburgian (20 Ma), Ottnangian (17.5 Ma), Lower Karpatian (16.5 Ma) and the Karpatian/ Badenian stage boundary (16 Ma). Convergence rates, which were calculated for the four intervening time intervals, range from about 3 mm/yr to 5 mm/yr. These values compare well with estimated convergence rates reconstructed for the Miocene in the western Eastern Alps (Schmid et al., 1996), as well as with plate tectonic constraints on Tertiary convergence rates (Dewey et al., 1989). Dewey, J., Helman, M.L., Turco, E., Hutton, D.H.W.&Knott, S.D., 1989. Kinematics of the western Mediterranean, in: N.P. Coward, D. Dietrich & R.G. Park (eds.), Alpine Tectonics, Geol. Soc. Spec. Publ., 45: 265-283. Schmid, S.M., Pfiffner, O.A., Frotzheim, N., Schönborn, G. & Kissling, E., 1996. Geophysical-geological transect and tectonic evolution of the Swiss-Italian Alps. Tectonics, 15: 1036-1064.

Beidinger, A.; Decker, K.; Zamolyi, A.; Hölzel, M.; Hoprich, M.; Strauss, P.

2009-04-01

193

Strain variation in thrust sheets of the Sevier fold-and-thrust belt, Idaho-Utah-Wyoming: Implications for section restoration and wedge taper evolution  

Energy Technology Data Exchange (ETDEWEB)

The total displacement field for any thrust sheet is made up of two independent components: translation along the fault, and internal deformation of the sheet. The internal deformation can be quantified by measuring strain within the sheet. Although strain within external thrust sheets is typically inhomogeneous at the mesoscopic scale, strain does show regular patterns of variation at the scale of the sheet as a whole. The total internal deformation of a sheet can be represented by a deformation profile which has a simple geometric form at the largest scale, based on information available from well studied thrust sheets. Using such known profiles and compatibility constraints it is possible to minimize the data needed to define the deformation profiles of other sheets. The profiles can be then used to help in unstraining sheets during restoration in cross-section balancing. Based on field observations and the geometric patterns of deformation profiles, most external thrust sheets, including those in the Sevier fold-and-thrust belt (FTB) of ID-UT-WY, show early layer-parallel shortening (LPS) as the most important component of internal deformation. This strain can be removed in a straightforward manner during the last stage of restoration, and significantly affects the geometry of the restored section. In the northern ID-UT-WY FTB salient, the restored basin taper is reduced by 6[degree] to less than 4[degree] for most of the major thrust sheets. Since original basin taper may have important implications for thrust belt evolution, changes in basin taper resulting from strain removal for thrust sheets significantly affects the interpretation of FTB evolution in an area.

Mitra, G. (Univ. of Rochester, NY (United States). Dept. of Geological Sciences)

1993-04-01

194

An Experimental Study of the Viscoseal Bearing.  

Science.gov (United States)

The experimental data obtained from two groove geometries of the viscoseal bearing were analysed to study the bearing characteristics and the sealing performance. The experimental bearing characteristics were compared with the Dubois and Ocvirk Short-bear...

C. K. Shah

1969-01-01

195

Some Applications of Journal Bearing Green's Functions.  

Science.gov (United States)

The fundamental Green's Function for journal bearings are applied to both externally pressurized bearings and self-acting bearings. The Green's Function solution agrees very well with the theoretical solution of a self-acting bearing with Sommerfeld condi...

J. Modrey

1964-01-01

196

Minimum Thrust Load Control for Floating Wind Turbine  

DEFF Research Database (Denmark)

— Offshore wind energy capitalizes on the higher and less turbulent wind at sea. Shallow water sites are pro?table for deployment of monopile wind turbines at water depths of up to 30 meters. Beyond 30 meters, the wind is even stronger and less turbulent. At these depths, ?oating wind turbines become pro?table, capable of accessing unexploited wind resources while reaching regions of new consumers. However, ?oating wind turbines are subject to reduced structural stiffness which results in instabilities when standard wind turbine control systems are applied. Based on optimal control, this paper presents a new minimum thrust control strategy capable of stabilizing a ?oating wind turbine. The new control strategy explores the freedom of variable generator speed above rated wind speed. A comparison to the traditional constant speed strategy, shows improvements in structural fore-aft oscillations and power stability when using the new control strategy.

Christiansen, SØren; Bak, Thomas

2012-01-01

197

Hudson Valley Fold and Thrust Belt Field Trip (Structural Geology)  

Science.gov (United States)

This structural geology field trip in the Hudson Valley region reinforces class discussions about fold and thrust belts and thin-skinned tectonics. Students observed a ramp anticline over a ramp-flat geometry fault. The anticline has minor faulting and veining in the hinge zone and folding occurred by flexural slip (evident from down-dip slickenlines on bedding surfaces). Students make observations and sketches of the outcrop and take strike and dip measurements of bedding and fault surfaces. Students can also look for a very weak cleavage. Students can use attitude measurements to reinforce key principles of stereonets including plotting lines, planes, and poles and interpreting the orientation of the fold axis (or other information) from these nets.

Growdon, Martha

198

Thermal evolution of the Redbank thrust system, central Australia: Geochronological and phase-equilibrium constraints  

Science.gov (United States)

We constrain the thermal history of the Redbank thrust in central Australia by reviewing and substantially expanding on a small set of thermobarometric and field data, 40Ar/39Ar hornblende and biotite ages as well as chemical Th-U-Pb monazite and xenotime ages. Metamorphic PT data indicate peak conditions between 620°C and 800°C and between ˜6 and 8 kbar within the thrust system. For at least 50 km north of the thrust system (hanging wall) peak metamorphic conditions are fairly uniformly around ˜850°C and 10 kbar. The geochronological data are interpreted to indicate that these PT conditions were reached around 1780 Ma (Strangways Orogeny) north of the Redbank thrust zone and between around 1680 and ˜1600 (Argilke and Chewings tectonic events). Major cooling below or reheating up to 500°C of the entire region occurred around 1140 Ma (Teapot event). However, initial 40Ar/39Ar ages of biotites within and north of the thrust zone define the initiation of (re)activation along the Redbank thrust around 420 Ma. In combination we interpret the data to indicate exhumation of the thrust system from near 20 km to the surface between 420 Ma and 320 Ma. Recent authors have shown that exhumation processes like that described for the Redbank thrust here may have a substantial influence on the occurrence of intraplate orogeny by truncating a highly radioactive upper crust. Thus, our data may help to constrain the nature of intraplate orogeny in central Australia.

Biermeier, C.; Stüwe, K.; Foster, D. A.; Finger, F.

2003-02-01

199

Thermal ground water flow systems in the thrust zone in southeastern Idaho  

Energy Technology Data Exchange (ETDEWEB)

The results of a regional study of thermal and non-thermal ground water flow systems in the thrust zone of southern Idaho and western Wyoming are presented. The study involved hydrogeologic and hydrochemical data collection and interpretation. Particular emphasis was placed on analyzing the role that thrust zones play in controlling the movement of thermal and non-thermal fluids.

Ralston, D.R.

1983-05-01

200

A Control Approach for Thrust-Propelled Underactuated Vehicles and its Application to VTOL Drones  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A control approach is proposed for a class of underactuated vehicles in order to stabilize reference trajectories either in thrust direction, velocity, or position. The basic modeling assumption is that the vehicle is propulsed via a thrust force along a single body-fixed direction and that it has f...

Hua, Minh-Duc; Hamel, Tarek; Morin, Pascal; Samson, Claude

 
 
 
 
201

Tme-300 Computer Evaluation of Telectro-Mek, Inc. Ram Drag and Thrust Computers.  

Science.gov (United States)

The net thrust (TME-300), gross thrust (TME-300C1), ram drag (TME-300-C2) computers were evaluated on a J79-GE-8 engine at a simulated flight conditions ranging from static sea level to 50,000 ft, M = 1.4. The purpose of these tests was to determine the a...

J. E. Femia

1965-01-01

202

Non-contact thrust stand calibration method for repetitively pulsed electric thrusters.  

UK PubMed Central (United Kingdom)

A thrust stand calibration technique for use in testing repetitively pulsed electric thrusters for in-space propulsion has been developed and tested using a modified hanging pendulum thrust stand. In the implementation of this technique, current pulses are applied to a solenoid to produce a pulsed magnetic field that acts against a permanent magnet mounted to the thrust stand pendulum arm. The force on the magnet is applied in this non-contact manner, with the entire pulsed force transferred to the pendulum arm through a piezoelectric force transducer to provide a time-accurate force measurement. Modeling of the pendulum arm dynamics reveals that after an initial transient in thrust stand motion the quasi-steady average deflection of the thrust stand arm away from the unforced or "zero" position can be related to the average applied force through a simple linear Hooke's law relationship. Modeling demonstrates that this technique is universally applicable except when the pulsing period is increased to the point where it approaches the period of natural thrust stand motion. Calibration data were obtained using a modified hanging pendulum thrust stand previously used for steady-state thrust measurements. Data were obtained for varying impulse bit at constant pulse frequency and for varying pulse frequency. The two data sets exhibit excellent quantitative agreement with each other. The overall error on the linear regression fit used to determine the calibration coefficient was roughly 1%.

Wong AR; Toftul A; Polzin KA; Pearson JB

2012-02-01

203

Self lubricating fluid bearings  

International Nuclear Information System (INIS)

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

1979-05-07

204

Combining Countercurrent Shear Flow Control and Transverse Jets for Fluidic Thrust Vector Control  

Science.gov (United States)

Countercurrent shear flow control has been established as an effective method for thrust vector control but has been challenged by hardware integration issues. Recent developments in fluidic thrust vector control have focused on nozzle interior methods that skew the throat of the nozzle using multiple transverse jets. The present work is motivated to combine these two flow control approaches to create a thrust vector control technique with enhanced performance. A combined computational and experimental effort was undertaken to consider the integration of these two flow control techniques. A simple configuration of a channel flow was used with consideration of various geometrical and operating conditions. It is apparent that the employment of countercurrent flow control does enhance the thrust vector control performance over a single transverse jet. The influence of countercurrent shear on the turbulence created with the transverse jet will be studied to help understand how the two flow control methodologies contribute to the pressure gradients required for thrust vectoring.

Echavarria Diaz-Guardamino, Ignacio; Forliti, David

2007-11-01

205

Nanoprecipitation in bearing steels  

International Nuclear Information System (INIS)

?-phase is the main hardening species in bearing steels and appears in both martensitically and bainitically hardened microstructures. This work presents a survey of the microstrucural features accompanying nanoprecipitation in bearing steels. Nanoprecipitate structures formed in 1C-1.5Cr wt.% with additions of Cr, Mn, Mo, Si and Ni are studied. The work is combined with thermodynamic calculations and neural networks to predict the expected matrix composition, and whether this will transform martensitically or bainitically. Martensite tetragonality, composition and the amount of retained austenite are related to hardness and the type of nanoprecipitate structures in martensitic grades. The ?-phase volume fraction, the duration of the bainite to austenite transformation and the amount of retained austenite are related to hardness and a detailed quantitative description of the precipitate nanostructures. Such description includes compositional studies using energy-dispersive spectroscopy, which shows that nanoprecipitate formation takes place under paraequilibrium. Special attention is devoted to a novel two-step bainite tempering process which shows maximum hardness; we prove that this is the most effective process for incorporating solute into the precipitates, which are finer than those resulting from one-step banitic transformation processes.

2011-01-01

206

Nanoprecipitation in bearing steels  

Energy Technology Data Exchange (ETDEWEB)

{theta}-phase is the main hardening species in bearing steels and appears in both martensitically and bainitically hardened microstructures. This work presents a survey of the microstrucural features accompanying nanoprecipitation in bearing steels. Nanoprecipitate structures formed in 1C-1.5Cr wt.% with additions of Cr, Mn, Mo, Si and Ni are studied. The work is combined with thermodynamic calculations and neural networks to predict the expected matrix composition, and whether this will transform martensitically or bainitically. Martensite tetragonality, composition and the amount of retained austenite are related to hardness and the type of nanoprecipitate structures in martensitic grades. The {theta}-phase volume fraction, the duration of the bainite to austenite transformation and the amount of retained austenite are related to hardness and a detailed quantitative description of the precipitate nanostructures. Such description includes compositional studies using energy-dispersive spectroscopy, which shows that nanoprecipitate formation takes place under paraequilibrium. Special attention is devoted to a novel two-step bainite tempering process which shows maximum hardness; we prove that this is the most effective process for incorporating solute into the precipitates, which are finer than those resulting from one-step banitic transformation processes.

Barrow, A.T.W. [SKF University Technology Centre, Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ (United Kingdom); Rivera-Diaz-del-Castillo, P.E.J., E-mail: pejr2@cam.ac.uk [SKF University Technology Centre, Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ (United Kingdom)

2011-11-15

207

A study of variable thrust, variable specific impulse trajectories for solar system exploration  

Science.gov (United States)

A study has been performed to determine the advantages and disadvantages of variable thrust and variable Isp (specific impulse) trajectories for solar system exploration. There have been several numerical research efforts for variable thrust, variable Isp, power-limited trajectory optimization problems. All of these results conclude that variable thrust, variable Isp (variable specific impulse, or VSI) engines are superior to constant thrust, constant Isp (constant specific impulse; or CSI) engines. However, most of these research efforts assume a mission from Earth to Mars, and some of them further assume that these planets are circular and coplanar. Hence they still lack the generality. This research has been conducted to answer the following questions: (1) Is a VSI engine always better than a CSI engine or a high thrust engine for any mission to any planet with any time of flight considering lower propellant mass as the sole criterion? (2) If a planetary swing-by is used for a VSI trajectory, is the fuel savings of a VSI swing-by trajectory better than that of a CSI swing-by or high thrust swing-by trajectory? To support this research, an unique, new computer-based interplanetary trajectory calculation program has been created. This program utilizes a calculus of variations algorithm to perform overall optimization of thrust, Isp, and thrust vector direction along a trajectory that minimizes fuel consumption for interplanetary travel. It is assumed that the propulsion system is power-limited, and thus the compromise between thrust and Isp is a variable to be optimized along the flight path. This program is capable of optimizing not only variable thrust trajectories but also constant thrust trajectories in 3-D space using a planetary ephemeris database. It is also capable of conducting planetary swing-bys. Using this program, various Earth-originating trajectories have been investigated and the optimized results have been compared to traditional CSI and high thrust trajectory solutions. Results show that VSI rocket engines reduce fuel requirements for any mission compared to CSI rocket engines. Fuel can be saved by applying swing-by maneuvers for VSI engines; but the effects of swing-bys due to VSI engines are smaller than that of CSI or high thrust engines.

Sakai, Tadashi

208

Grease lubrication in rolling bearings  

CERN Multimedia

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

Lugt, Piet M

2012-01-01

209

Bearing development program for a 25-kWe solar-powered organic Rankine-cycle engine  

Energy Technology Data Exchange (ETDEWEB)

This report summarizes the bearing development program for a 25-kWe power conversion subsystem (PCS) consisting of an organic Rankine-cycle engine, permanent magnet alternator (PMA) and rectifier to be used in a 100-kWe point-focusing distributed receiver solar power plant. The engine and alternator were hermetically sealed and used toluene as the working fluid. The turbine, alternator, and feed pump (TAP) were mounted on a single shaft operating at speeds up to 60,000 rev/min. Net thermal-to-electric efficiencies in the range of 21 to 23% were demonstrated at the maximum working fluid temperature of 400/sup 0/C (750/sup 0/F). A chronological summary of the bearing development program is presented. The primary causes of bearing wear problems were traced to a combination of rotordynamic instability and electrodynamic discharge across the bearing surfaces caused by recirculating currents from the PMA. These problems were resolved by implementing an externally supplied, flooded-bearing lubrication system and by electrically insulating all bearings from the TAP housing. This program resulted in the successful development of a stable, high-speed, toluene-lubricated five-pad tilting-pad journal bearing and Rayleigh step thrust bearing system capable of operating at all inclinations between horizontal and vertical.

Nesmith, B.

1985-09-15

210

Unsteady deformation along the southwest Spanish Pyrenean thrust front  

Science.gov (United States)

A history of unsteady fault slip is recorded by magnetic reversals in a section of Oligocene continental growth strata on the forelimb of the blind thrust Santo Domingo-Tafalla anticline. Progressive tilting during deposition of the fluvial-lacustrian mollase of the Campodarbe formation is related to slip on the foreland dipping backthrust. Tilt rates calculated with 0.15-.7 Ma resolution, constrained by the magnetostratigraphy, vary from 3°/myr to 45°/myr, indicating times of near quiescence alternating with more rapid deformation over the 5 myr history recorded in the section. The new magnetostratigraphy established in this study is further west than previous studies and provides new age control for late-stage deformation of the Pyrenean thrust front. A dense array of more than 500 samples from 164 horizons over the 3,300 m of growth section was used to develop the magnetostratigraphy. A progressive 15-step thermal demagnetization (150°-690°C) was used to determine the characteristic remanent magnetization (ChRM) by principal component analysis (PCA). The ChRM is primarily carried by magnetite and hematite, and goethite is also present in the samples. PCA and calculation of virtual geomagnetic poles determined normal and reversed polarities within the section that are correlated to the geomagnetic polarity timescale. Previous work in the Campodarbe Fm ~30 km to the east by Hogan and Burbank (1996) B. Oliva-Urcia (personal comm.) tie the base of the section to C12r, and preliminary results suggest the Campodarbe Fm extends into C8. The first 1,000 m of section is pregrowth. The onset of the progressive unconformity in the section records the onset of deformation at ~30.5 Ma. Initial deformation was rapid with 25° of dip change over 0.65 myr (38°/myr). The next 0.5 myr was nearly quiescent with only 2° of dip change (4°/myr). Subsequently deformation steadily increased to 15°/my before returning to rates near 35°/Ma. Thus, this study shows the range of fault growth unsteadiness, as well as new age controls for late-stage deformation of the Spanish Pyrenees.

Teletzke, A. L.; Pares, J. M.; Kodama, K. P.; Anastasio, D. J.

2011-12-01

211

Crustal shortening on the Lombard thrust: A detailed study along the southwest Montana Transverse Zone  

Energy Technology Data Exchange (ETDEWEB)

Recent drilling of the Devil's Fence Anticline on the Helena Salient of the Cordilleran thrust belt in SW Montana shows that the Lombard thrust sheet has been translated eastward by as much as 70 km, several times greater than all previous estimates. In the southern part of the salient the principal frontal thrust becomes a transverse ramp with significant dextral strike slip separation estimated at about 20 km. Part of the discrepancy between the 70 km of thrust slip and 20 km of strike slip may be manifested as internal shortening of the thrust sheet. The study area, situated between the Devil's Fence Anticline and the southwest Montana Transverse Zone, shows significant internal shortening within the thrust sheet. The internal shortening is partitioned among tight folds and subsequent faulting, minor decollements and homogeneous layer parallel deformation. At least 9 major N to Ne plunging folds, about 1 km in wavelength with an average plunge of 20 degrees, account for a total shortening of approximately 40% over a map distance of less than 5 km. Local fault movement accounts for 5--15% shortening. Layer parallel shortening in the form of cleavage and calcite twinning that occurred prior to thrusting may account for an additional 10%. The amount of internal shortening within this study area alone may provide an explanation for the discrepancies in the two estimates of regional shortening.

Zenero, R.R. (Western Michigan Univ., Kalamazoo, MI (United States). Geology Dept.)

1994-04-01

212

Is tongue thrust that develops during orthodontic treatment an unrecognized potential road block?  

Directory of Open Access Journals (Sweden)

Full Text Available The role of tongue thrust has often been suspected, long debated and largely dispelled as a primary etiological factor of malocclusion. However, tongue thrust may contribute to poor occlusal intercuspation both during and after treatment. A tongue thrust may also develop during orthodontic mechanotherapy as a result of the transient creation of intra and interarch spaces and this little recognized phenomenon was found to occur in many randomly followed cases. In many instances, this seemingly adaptive and secondary response of the tongue posture and function may persist and thereafter impede the resolution of intra and interarch problems.

Chawla H; Suri Sanjay; Utreja A

2006-01-01

213

A METHOD OF COMPUTER CALCULATION OF AXIAL THRUST AND INTERNAL LEAKAGE IN CENTRIFUGAL PUMPS  

Directory of Open Access Journals (Sweden)

Full Text Available A simple method of calculation of radial pressure distribution on a disc rotating in a casing and then the axial thrust in centrifugal pumps is presented. The method is based on integral relations and allows to estimate rapidly the axial thrust value with accuracy sufficient for technical applications (the error less than 15%). The method allows to compute simultaneously Internal leakage losses in centrifugal pumps. The presented method may also be useful for the calculation of the pressure distribution and the axial thrust in other rotating machines, such as compressors, gas turbines, water turbines, hydraulic torque convertors and paper-pulp mills.

Waldemar J?dral

1991-01-01

214

SOURCE TERM TARGETED THRUST FY 2005 NEW START PROJECTS  

International Nuclear Information System (INIS)

While a significant amount of work has been devoted to developing thermodynamic data. describing the sorption of radionuclides to iron oxides and other geomedia, little data exist to describe the interaction of key radionuclides found in high-level radioactive waste with the uranium surfaces expected in corroded spent nuclear fuel (SNF) waste packages. Recent work indicates that actinide adsorption to the U(VI) solids expected in the engineered barrier system may play a key role in the reduction of dissolved concentrations of radionuclides such as Np(V). However, little is known about the mechanism(s) of adsorption, nor are the thermodynamic data available to represent the phenomenon in predictive modeling codes. Unfortunately, this situation makes it difficult to consider actinide adsorption to the U(VI) silicates in either geochemical or performance assessment (PA) predictions. The primary goal in the Source Term Targeted Thrust area is to ''study processes that control radionuclide release from the waste form''. Knowledge of adsorption of actinides to U(VI) silicate solids its and parameterization in geochemical models will be an important step towards this goal.

2005-01-01

215

Kinematics of the Main Caucasus Thrust near Baku, Azerbaijan  

Science.gov (United States)

The Absheron Peninsula lies at the junction of the ˜ E-W striking, north-verging, intra-continental Main Caucasus Thrust Fault (MCTF) and the Central Caspian Seismic Zone (CCSZ). The MCTF accommodates shortening between the Lesser and Greater Caucasus Mountains, and the CCSZ is thought to reflect the early stages of subduction of the southern Caspian ocean basin beneath the northern Caspian continental lithosphere. Both structures accommodate ongoing, roughly N-S continent-continent collision between the Arabian and Eurasian plates. GPS measurements along an ~ N-S traverse crossing the Lesser Caucasus, Kura Depression, and Absheron Peninsula near the city of Baku, Azerbaijan, indicate high strain rates that appear to be continuous with high strain rates along the MCTF located west of the Peninsula. Simple models for strain accumulation along an ESE extension of the MCTF and a SSE-striking, predominantly right-lateral strike-slip fault (both structures being consistent with the regional tectonics) provide reasonable fits to the observed deformation. The MCTF has experienced a number of M > 6.5 historic earthquakes, including the 1991, M=7.1 Racha, Georgia event. Due to the close proximity of the strain anomaly to Baku, and the potential environmental and economic impact from damage to the petroleum infrastructure in this highly industrialized area, further studies are needed to determine better the kinematics of this "transition" zone and possible implications for future earthquake activity.

Floyd, M. A.; Kadirov, F. A.; Alizada, A.; Guliev, I.; Reilinger, R. E.; Kuleli, S.; King, R. W.; Toksoz, M. N.

2011-12-01

216

SOURCE TERM TARGETED THRUST FY 2005 NEW START PROJECTS  

Energy Technology Data Exchange (ETDEWEB)

While a significant amount of work has been devoted to developing thermodynamic data. describing the sorption of radionuclides to iron oxides and other geomedia, little data exist to describe the interaction of key radionuclides found in high-level radioactive waste with the uranium surfaces expected in corroded spent nuclear fuel (SNF) waste packages. Recent work indicates that actinide adsorption to the U(VI) solids expected in the engineered barrier system may play a key role in the reduction of dissolved concentrations of radionuclides such as Np(V). However, little is known about the mechanism(s) of adsorption, nor are the thermodynamic data available to represent the phenomenon in predictive modeling codes. Unfortunately, this situation makes it difficult to consider actinide adsorption to the U(VI) silicates in either geochemical or performance assessment (PA) predictions. The primary goal in the Source Term Targeted Thrust area is to ''study processes that control radionuclide release from the waste form''. Knowledge of adsorption of actinides to U(VI) silicate solids its and parameterization in geochemical models will be an important step towards this goal.

NA

2005-10-05

217

Flywheel Challenge: HTS Magnetic Bearing  

International Nuclear Information System (INIS)

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

218

Wheel-chair brake control comprises cylinder segments, thrust block with thrust surface, handle with link part, pivot point, operating-bar, and brake-pull.  

UK PubMed Central (United Kingdom)

The base unit (1) of the control has a top cylinder segment (11) gripping over the handle. Underneath the top cylinder segment is a bottom hollow segment (12) along the inner surface of the back of which runs a thrust-block (122) below which is a cable opening (123). A thrust surface (124) is formed on an inner wall defining the bottom hollow segment which has a front opening defined by two side walls and a base. The handle (2) has a link-part (21) vertically positioned in a rear and front segment. The top end of the link-part is connected to the base unit and swivels on a pivot point (212). A hollow cavity (211) behind a vertical rear wall connects with the thrust block. An operating-bar (3) has a top end joined to the link-part and a bottom end joined to one end of a brake-pull (5).

219

Hot Gas Secondary Injection Thrust Vector Control Demonstration Program. Volume III.  

Science.gov (United States)

This program was established to design, develop, and demonstrate a hot gas secondary injection thrust vector control system (HGSITVC) for large solid propellant rocket motors. Phase I of the program was the design, analysis, and optimization of a 156 in. ...

C. G. Kennedy D. M. Cox R. T. Minert

1968-01-01

220

rf power system for thrust measurements of a helicon plasma source.  

Science.gov (United States)

A rf power system has been developed, which allows the use of rf plasma devices in an electric propulsion test facility without excessive noise pollution in thruster diagnostics. Of particular importance are thrust stand measurements, which were previously impossible due to noise. Three major changes were made to the rf power system: first, the cable connection was changed from a balanced transmission line to an unbalanced coaxial line. Second, the rf power cabinet was placed remotely in order to reduce vibration-induced noise in the thrust stand. Finally, a relationship between transmission line length and rf was developed, which allows good transmission of rf power from the matching network to the helicon antenna. The modified system was tested on a thrust measurement stand and showed that rf power has no statistically significant contribution to the thrust stand measurement. PMID:20687758

Kieckhafer, Alexander W; Walker, Mitchell L R

2010-07-01

 
 
 
 
221

rf power system for thrust measurements of a helicon plasma source.  

UK PubMed Central (United Kingdom)

A rf power system has been developed, which allows the use of rf plasma devices in an electric propulsion test facility without excessive noise pollution in thruster diagnostics. Of particular importance are thrust stand measurements, which were previously impossible due to noise. Three major changes were made to the rf power system: first, the cable connection was changed from a balanced transmission line to an unbalanced coaxial line. Second, the rf power cabinet was placed remotely in order to reduce vibration-induced noise in the thrust stand. Finally, a relationship between transmission line length and rf was developed, which allows good transmission of rf power from the matching network to the helicon antenna. The modified system was tested on a thrust measurement stand and showed that rf power has no statistically significant contribution to the thrust stand measurement.

Kieckhafer AW; Walker ML

2010-07-01

222

Lateral versus anterior thoracic thrusts in the generation of airway pressure in anaesthetised pigs.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Anterior chest thrusts (with the subject sitting or standing and thrusts applied to the lower sternum) are recommended by the Australian Resuscitation Council as part of the sequence for clearing upper airway obstruction by a foreign body. Lateral chest thrusts (with the victim lying on their side) are no longer recommended due to a lack of evidence. We compared anterior, lateral chest and abdominal thrusts in the generation of airway pressures using a suitable animal model. METHODS: This was a repeated-measures, cross-over, clinical trial of eight anaesthetised, intubated, adult pigs. For each animal, ten trials of each technique were undertaken with the upper airway obstructed. A chest/abdominal pressure transducer, a pneumotachograph and an intra-oesophageal balloon catheter recorded chest/abdominal thrust, expiratory air flows, airway and intrapleural pressures, respectively. RESULTS: The mean (SD) thrust pressures generated for the anterior, lateral and abdominal techniques were 120.9 (11.0), 135.2 (20.0), and 142.4 (27.3)cmH(2)O, respectively (p<0.0001). The mean (SD) peak expiratory airway pressures were 6.5 (3.0), 18.0 (5.5) and 13.8 (6.7)cmH2O, respectively (p<0.0001). The mean (SD) peak expiratory intrapleural pressures were 5.4 (2.7), 13.5 (6.2) and 10.3 (8.5)cmH(2)O, respectively (p<0.0001). At autopsy, no rib, intra-abdominal or intra-thoracic injury was observed. CONCLUSION: Lateral chest and abdominal thrust techniques generated significantly greater airway and pleural pressures than the anterior thrust technique. We recommend further research to provide additional evidence that may inform management guidelines for clearing foreign body upper airway obstruction.

Lippmann J; Taylor DM; Slocombe R; McDonald CF; Walker T; Nolan G

2013-04-01

223

A particle bed reactor based NTP in the 112,500 N thrust class  

International Nuclear Information System (INIS)

This paper discusses the application of a Particle Bed Reactor (PBR) to a 112,500 N thrust Nuclear Thermal Propulsion (NTP) Engine. The method of analysis is described, followed by a presentation of the results. It is concluded that the PBR would result in a very competitive NTP engine. In addition, due to the high power densities possible with a PBR, high thrust/weight ratios are possible. This conclusion can be used to satisfy a variety of mission goals

1993-01-20

224

A particle bed reactor based NTP in the 112,500 N thrust class  

Energy Technology Data Exchange (ETDEWEB)

This paper discusses the application of a Particle bed Reactor (PBR) to a 112,500 N thrust Nuclear Thermal Propulsion (NTP) Engine. The method of analysis is described, followed by a presentation of the results. It is concluded that the PBR would result in a very competitive NTP engine. In addition, due to the high power densities possible with a PBR, high thrust/weight ratios are possible. This conclusion can be used to satisfy a variety of mission goals.

Ludewig, H.; Powell, J.R.; Lazareth, O.W. Jr.; Todosow, M.

1993-04-01

225

A particle bed reactor based NTP in the 112,500 N thrust class  

Energy Technology Data Exchange (ETDEWEB)

This paper discusses the application of a Particle Bed Reactor (PBR) to a 112,500 N thrust Nuclear Thermal Propulsion (NTP) Engine. The method of analysis is described, followed by a presentation of the results. It is concluded that the PBR would result in a very competitive NTP engine. In addition, due to the high power densities possible with a PBR, high thrust/weight ratios are possible. This conclusion can be used to satisfy a variety of mission goals.

Ludewig, H.; Powell, J.R.; Lazareth, O.W. Jr.; Todosow, M. (Reactor Systems Division, Department of Nuclear Energy, Brookhaven National Laboratory, Upton, New York 11973 (United States))

1993-01-20

226

Cross-strike Discontinuities in the Moine Thrust Belt of NW Scotland; their identity, tectonic significance, and visualisation.  

Science.gov (United States)

Abrupt lateral changes in thrust geometry occur in many mountain-building fold-and-thrust belts. Whilst many works have dealt with palinspastic reconstructions and transport-direction-parallel balanced cross-sections, far fewer show a full three-dimensional architecture, or examine how these lateral variations in thrust architecture can be linked via so-called 'transverse zones' that serve to demarcate different segments of the thrust belt. When identified, these transverse zones are commonly thought to be related to kinematic responses to irregularities generated across pre-existing, sometimes re-activated, sub-décollement basement faults, contrasts in pre-thrusting cover strata deformation across basement faults, development of duplex structures/antiformal stacks, and/or along-strike variations in mechanical stratigraphy. In many cases however the causative structure is concealed, either by distal parts of the thrust belt or by the foreland basin, and so must be deduced from the overall structural architecture. The amplitude and complexity of the disturbance associated with the transverse zone is typically much greater than amplitude of any irregularity identified in the basement below the thrust belt. In NW Scotland, the classic WNW-vergent Caledonian Moine Thrust Belt (MTB) incorporates a variety of crustal-scale segments. In the Assynt Culmination of the thrust belt, the Traligill Transverse Zone trends sub-parallel to the thrust transport direction, and is associated with an en echelon fault system cutting thrusts, with discontinuity of the thrust and thrust sheet architecture, and with oblique fold and thrust structures. This transverse zone is developed above a basement cross-fault which records repeated brittle reactivation of a Proterozoic shear zone. Thrusting thus deformed a sedimentary sequence that was already disrupted by faults aligned sub-parallel to the thrust transport direction. In the Kinlochewe district where the Loch Maree Fault Zone (LMF) transects the MTB, a fold-and thrust architecture can be clearly identified on the northern wall of the LMF. That architecture is in sharp contrast to classically imbricated repetitions on the southern wall of the LMF. The structural compartmentalization is thought to be a response to a significant offset of the pre-thrust template on the proto-LMF. Three-dimensional visualizations of these complexities are challenging to construct and deliver to the geological community - this presentation will include examples of British Geological Survey progress in rendering fold and thrust surfaces in 3D and making them interactively available to the end-user.

Kelly, Michael; Kearsey, Tim; Leslie, Graham; Ritchie, Calum; Krabbendam, Maarten; Williams, Graham

2013-04-01

227

Eastern slopes grizzly bear project  

Energy Technology Data Exchange (ETDEWEB)

The cumulative effects of human activities on the grizzly bears in the central Canadian Rockies are not well known. As a result, a project was initiated in 1994 to address the urgent requirement for accurate scientific information on the habitat and populations of grizzly bears in the area of the Banff National Park and Kananaskis Country. This area is probably the most heavily used and developed area where the grizzly still survives. The information gathered throughout the course of this study will be used to better protect and manage the bears and other sensitive carnivores in the region. Using telemetry, researchers are monitoring 25 grizzly bears which were radio-collared in a 22,000 square-kilometer area in the upper Bow Valley drainage of the eastern Alberta slopes. The researchers involved in the project are working with representatives from Husky Oil and Talisman Energy on the sound development of the Moose Mountain oil and gas field without adversely affecting the grizzly bear population. Information collected over seven years indicated that the grizzly bears have few and infrequent offspring. Using the information gathered so far, the location of the Moose Mountain to Jumping Pound pipeline was carefully selected, since the bears recover very slowly from high mortality, and also considering that the food and cover had already been compromised by the high number of roads, trails and other human activities in the area. The status of the population and habitat of the grizzly bear will be assessed upon the conclusion of the field research phase in 2001. Models will be updated using the data obtained during eight years and will assist in the understanding of complex variables that affect grizzly bears.

NONE

2001-01-01

228

The Relationship Between Thrust Faults and Structural Fractures in the Tarim Basin, China  

Directory of Open Access Journals (Sweden)

Full Text Available It is a problem that how thrust faults control the distribution of structural fractures in the exploration and development of fracture oil-reservoirs. One section of fracture outcrops in Ordovician carbonites is measured in the north margin of Tarim Basin, and two sections cross the Fault I in the central Tarim Basin are measured and processed in the paper. The development rule of structural fractures can be depicted by the fracture density, and the fractures near fault can be divided into two regions: the fracture zone controlled by fault and the fracture zone controlled by regional stress field. The ratio of fault-controlled fracture zone width to the throw of thrust fault is a very important parameter to depict the development of fractures influenced by thrust fault. The ratio is related to the mechanism, scale and throw of the thrust fault. The width of fault-controlled fracture zone can be predicted based on the mechanism and throw of the thrust fault. It is very helpful to the exploration and development of fault-controlled fracture reservoirs. Key words: Structural fractures; Fault-controlled fracture zone; Thrust fault; Fracture density

Jianfa Han; Guiting Hou; Bing Jing; Yan Ju; Le Li; Wei Ju

2011-01-01

229

Deformation in thrust-ramp anticlines and duplexes: implications for geometry and porosity  

Energy Technology Data Exchange (ETDEWEB)

A computerized kinematic model of thrust-ramp anticline geometry allows workers to predict the zones of greatest deformation in ramp anticlines and fault duplexes. The model assumes a constant cross-section area, symmetrical fold hinges, and slip in the hanging wall parallel to the ramp and forelimb. Assuming that the collapse of original porosity or the generation of secondary fracture porosity is proportional to deformation, the model can be used to predict porosity changes. Deformation in a single ramp anticline is greatest in the forelimb and backlimb, and may be absent in the crest. A duplex structure results from comparatively closely spaced thrusts that have a common upper detachment horizon. Relatively wide spacing between the duplex faults yields a bumpy roofed duplex as in the central Appalachians. Forelimbs may be deformed twice and should show greater porosity modification. Relatively close spacing between ramp-and-flat thrusts can produce a listric-fault, snakehead anticline geometry because younger faults deform the preexisting thrust slices. The resulting geometry is here called a snakehead duplex and appears to be fairly common, as in the Jumpingpound field in the Canadian Rockies. Each thrust slice within the duplex is deformed six times or more, providing the maximum opportunity for deformation-related porosity changes. Maximum fracture porosity should occur in thrusts having listric-fan or snakehead duplex geometry. Structures involving duplexes generally should be better than isolated ramp anticlines.

Groshong, R.H. Jr.; Usdansky, S.I.

1986-05-01

230

Thrust Evaluation of an Arcjet Thruster Using Dimethyl Ether as a Propellant  

Science.gov (United States)

This paper describes the performance of an arcjet thruster using dimethyl ether (DME) as a propellant. DME, an ether compound, has adequate characteristics for space propulsion systems; DME is storable in a liquid state without a high pressure or cryogenic device and requires no sophisticated temperature management. DME is gasified and liquefied simply by adjusting temperature, whereas hydrazine, a conventional propellant, requires an iridium-based particulate catalyst for its gasification. In this study, thrust of the designed kW-class DME arcjet thruster is measured with a torsional thrust stand. Thrust measurements show that thrust is increased with propellant mass flow rate, and that thrust using DME propellant is higher than when using nitrogen. The prototype DME arcjet thruster yields a specific impulse of 330 s, a thruster efficiency of 0.14, and a thrust of 0.19 N at 60-mg/s DME mass flow rate at 25-A discharge current. The corresponding discharge power and specific power are 2.3 kW and 39 MJ/kg.

Kakami, Akira; Beppu, Shinji; Maiguma, Muneyuki; Tachibana, Takeshi

231

Cathodoluminescence, fluid inclusion and stable C-O isotope study of tectonic breccias from thrusting plane of a thin-skinned calcareous nappe  

Science.gov (United States)

Basal hydraulic breccias of alpine thin-skinned Murá? nappe were investigated by means of cathodoluminescence petrography, stable isotope geochemistry and fluid inclusions analysis. Our study reveals an unusual dynamic fluid regime along basal thrust plane during final episode of the nappe emplacement over its metamorphic substratum. Basal thrusting fluids enriched in 18O, silica, alumina, alkalies and phosphates were generated in the underlying metamorphosed basement at epizonal conditions corresponding to the temperatures of 400-450°C. The fluids fluxed the tectonized nappe base, leached evaporite-bearing formations in hangingwall, whereby becoming oversaturated with sulphates and chlorides. The fluids further modified their composition by dedolomitization and isotopic exchange with the host carbonatic cataclasites. Newly formed mineral assemblage of quartz, phlogopite, albite, potassium feldspar, apatite, dravite tourmaline and anhydrite precipitated from these fluids on cooling down to 180-200°C. Finally, the cataclastic mush was cemented by calcite at ambient anchizonal conditions. Recurrent fluid injections as described above probably enhanced the final motion of the Murá? nappe.

Milovský, Rastislav; van den Kerkhof, Alfons; Hoefs, Jochen; Hurai, Vratislav; Prochaska, Walter

2012-03-01

232

Experimental analysis of journal bearings  

Energy Technology Data Exchange (ETDEWEB)

This study presents a comprehensive technique which could be applied to almost any rotating equipment to identify and diagnose journal bearing problems that relate to metal-to-metal bearing surface contact. Orbital measurements that describe bearing parameters in different modes of operation were experimentally obtained and analyzed. Such parameters may include: attitude angle, minimum oil film thickness, and the possibility of metal-to-metal rubbing occurrence. The general outline of the presented experimental technique was substantiated using the Raimondi-Boyd well documented design charts and good correlation between experimental and analytical results was obtained.

Elkholy, A.H. [United Arab Emirates Univ., Al-Ain (United Arab Emirates). Dept. of Mechanical Engineering; Elshakweer, A. [Global Engineering Technology, Kitchener, Ontario (Canada)

1994-12-31

233

Bears, Big and Little. Young Discovery Library Series.  

Science.gov (United States)

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

Pfeffer, Pierre

234

Mixed-mu superconducting bearings  

International Nuclear Information System (INIS)

A mixed-mu superconducting bearing is disclosed including a ferrite structure disposed for rotation adjacent a stationary superconductor material structure and a stationary permanent magnet structure. The ferrite structure is levitated by said stationary permanent magnet structure. 9 figs.

1995-09-05

235

Mixed-mu superconducting bearings  

Energy Technology Data Exchange (ETDEWEB)

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

Hull, John R. (Hinsdale, IL); Mulcahy, Thomas M. (Western Springs, IL)

1998-01-01

236

Bearing capacity of desiccated tailings  

Energy Technology Data Exchange (ETDEWEB)

The development of matric suctions in soils contributes to their shear strength, resulting in an enhanced factor of safety against bearing-capacity failure. In this paper, matric suction profiles of desiccated mine tailings are predicted from a steady-state solution for evaporative conditions, and from an isothermal mathematical model that simulates liquid and vapor water flow through soils. The shear-strength envelope with respect to matric suction is established by testing reconstituted tailings samples in a modified triaxial cell, in which matric suction can be controlled. The contribution of matric suction to the shear strength is interpreted as an additional apparent cohesion for use in bearing-capacity calculations. Because of the nonlinearity of the shear-strength profile, a numerical method of analysis is adopted to predict the ultimate bearing capacity of the desiccated tailings. A subsequent decrease in bearing capacity following 2D water infiltration into a partially capped tailings deposit and accompanying suction loss is investigated.

Rassam, D.W.; Williams, D.J. [Univ. of Queensland, Brisbane, Queensland (Australia). Dept. of Civil Engineering

1999-07-01

237

Optimizing journal bearing bit performance  

Energy Technology Data Exchange (ETDEWEB)

This article explains that continuous progress in the field of rock bit technology has produced many new designs and improved features in the tri-cone rock bits used today. Much of the research and advancements have centered around journal bearing systems, seals and lubricants leading to greatly extended bearing life. These improved bearing systems, incorporated into both tooth and insert-type bits, have not only increased the effective life of a rock bit, but have also allowed greater energy levels to be applied. This, in turn, has allowed for higher rates of penetration and lower costs per foot of hole drilled. Continuous improvements in journal bearing bits allowing them to run longer and harder have required similar advancements to be made in cutting structures. In tooth bit designs, these improvements have been basically limited to the areas of gauge protection and to application of hardfacing materials.

Moerbe, O.E.; Evans, W.

1986-10-01

238

Testing and Lubrication for Single Race Bearings  

Energy Technology Data Exchange (ETDEWEB)

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

Steinhoff, R.G.

1998-03-04

239

Subduction, platform subsidence, and foreland thrust loading: The late Tertiary development of Taranaki Basin, New Zealand  

Science.gov (United States)

Borehole, seismic, and gravity data are used to investigate deformation of continental lithosphere at a Miocene collisional zone. Deformation is manifested in the three following principal forms: a long wavelength (>500 km) platform subsidence ascribed to mantle convection; flexural deformation on a scale of 100-200 km due to crustal thrusting at the eastern boundary of the Taranaki Basin; and a ductile thickening, evident on the deep seismic section of Taranaki Basin, that occurs on a scale of ˜10 km. Evidence for flexural deformation principally comes from the deep seismic section that shows a 150-km wavelength bending of the Moho down toward the major zone of thrusting within the Taranaki Fault Zone. Paleowater depths, however, provide evidence for an initial early Miocene regional subsidence that is too long in wavelength to be explained by flexure induced from thrust sheet loading. Instead, we propose that this broad "platform subsidence" was driven by loading from a deep source, probably subduction-induced flow in the mantle. By ˜22-19 Ma, 1-2 km of water existed over most of the area now occupied by South Taranaki Basin. By ˜19-17 Ma the water depth in the zone east of the Taranaki Basin, the Taranaki Fault Zone, had been replaced by rock due to submarine thrusting and crustal thickening. This build up of submarine topography in the Taranaki Fault Zone constitutes part of the load (25±8 MPa) that created and maintains South Taranaki Basin. Gravity data place further constraints on loading at the thrust front and point to an additional intracrustal loading, equivalent to 15±7 MPa over a 50-km-wide zone. This intracrustal load is explained as being due to thick-skinned thrusting bringing denser, lower-crustal rocks nearer to the surface in the thrust zone. The complete load on the Taranaki foreland is therefore in three parts; the submarine-topographic load, the intracrustal load, and the loading of infilling sediments.

Holt, W. E.; Stern, T. A.

1994-10-01

240

Independent Cough Flow Augmentation by Glossopharyngeal Breathing Plus Table Thrust in Muscular Dystrophy.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The purpose of the present study was to compare the unassisted cough peak flow (CPF) of patients affected by muscular dystrophy with CPF augmented by various techniques, including maximal depth glossopharyngeal breathing (GPB) combined with a subsequent self-induced thoracic or abdominal thrust. DESIGN: All of the motorized wheelchair-dependent patients with muscular dystrophy who had previously mastered GPB were trained at home to increase their cough efficacy. This training involved maneuvering their wheelchair against the edge of a specially built table to autonomously produce a thoracic and/or abdominal thrust timed to the opening of the glottis for an independently assisted cough. Both unassisted and variously assisted CPFs were compared. RESULTS: The 18 patients (17 men/1 woman) with muscular dystrophy, aged 21.1 ± 5.4 yrs, achieved variously assisted CPFs that were significantly higher than the spontaneous CPF (P < 0.001), with assisted CPFs but not unassisted CPFs that significantly exceeded a reported efficacious cough threshold value of 160 liters/min (P < 0.001). Moreover, increases in the CPFs by personal assistance including air stacking by manual resuscitator and thoracoabdominal thrust (326.4 ± 79.5 liters/min) or by GPB and thoracoabdominal thrust (326.4 ± 87.5 liters/min) were not significantly different (P = 0.07) from the CPFs independently attained by GPB plus independently maneuvering a wheelchair for a table thrust (310.3 ± 74.7 liters/min). CONCLUSIONS: The independently assisted (GPB plus table thrust) CPF was comparable to the CPFs that required personal assistance for air stacking and abdominal thrusts. Therefore, for patients with muscular dystrophy, this physical medicine technique and cough-assisted techniques that require personal intervention are strongly recommended.

Bianchi C; Carrara R; Khirani S; Tuccio MC

2013-06-01

 
 
 
 
241

Quaternary deformation associated with the Tripoli-Roum Thrust, and the rise of the lebanese coast.  

Science.gov (United States)

The Tripoli-Roum Thrust, which is part of the Levant Fault zone, appears to take up most of the shortening perpendicular to the Yammuneh Fault, thus producing the rise of Mount Lebanon since the late Neogene. In northern Lebanon, there is clear field evidence of active and recent folding and faulting along this thrust system. Three principal faults, oriented ~NNE-SSW, cut through the recent topography north of Tripoli. These oblique right-lateral strike-slip thrust ramps deform Neogene (Vindobonian to Astian) and Quaternary sedimentary and volcanic beds. The northernmost ramp is responsible for the growth of the young, asymmetric, Borj-el-Arab anticline, which folds Quaternary beachrocks and conglomerates, and reaches the Mediterranean coastline near Aabdé. This feature (thrust and ramp-anticline) continues offshore Tripoli, north of the Palmier and Rankine islands, and is probably responsible for the asymmetric uplift of shorelines and marine-cut terraces topping the islands. Active reverse faulting along the Tripoli-Roum thrust at sea appears to be also responsible for the rise of the many paleo-seacliffs and marine terraces found up to 500m asl along the Lebanese coast between Aabdé in the North and Saida in the South. Near Tabarja, and in the islands offshore Tripoli, we interpret the lowest uplifted marine terraces and double shoreline "trottoirs" identified and mapped by P. Sanlaville, to result from recurrent coseismic uplift during two or three seismic events on the offshore thrust. The last of these events was probably that which destroyed Beyrouth in 551A.D. Shell datings of the uplifted trottoirs yield 0,5 to 0,7 mm/yr as a first estimate of the uplift rate, relative to sea level, of the hanging wall of the Tripoli-Roum thrust ramp.

Elias, A.; Tapponnier, P.; Jacques, E.; Daëron, M.; Klinger, Y.; Sursock, A.

2003-04-01

242

Hydrocarbon generation in Health formation (Mississippian) in Montana thrust belt in response to tectonic burial  

Energy Technology Data Exchange (ETDEWEB)

The Heath Formation of the Big Snowy Group (Mississippian) in Montana and North Dakota consists of dark-gray to black, petroliferous shale and limestone with up to 19.9% total organic carbon (TOC) and 20 gal of oil per ton. The Heath is considered a source rock for the overlying Tyler Formation as well as a possible oil-shale deposit. Regionally, the Heath is immature to marginally mature with respect to hydrocarbon generation, except in the deeper part of the Williston basin, in a few deeply buried areas in the central Montana trough, and in the Montana thrust belt. Along the northern margin of the Helena salient of the Montana thrust belt, samples from the Heath contain 0.20-3.59 wt. % TOC, with most containing over 0.88%. Vitrinite reflectance ranges from 3.77 to 4.72% and the thermal alteration index is 4+ to 5, indicating that maturation proceeded beyond oil, wet gas, and dry gas preservation limits. Thus, the Heath Formation here passed through peak hydrocarbon generation zones and hydrocarbons may have been thermally destroyed. Modeling of the depositional and thermal history prior to thrusting, using the Lopatin method, indicates maturation slightly below the oil generation window. This suggests that hydrocarbon generation occurred after thrusting, probably in response to tectonic burial beneath thrust sheets. This conclusion is also supported by vitrinite reflectance values from the Heath in the thrust belt compared with reflectance of 0.48-0.67% east of the thrust belt in central Montana.

Longden, M.R.; Banowsky, B.R.; Woodward, L.A.

1988-07-01

243

Traceable Calibration of the 3 axis Thrust Vector in the mN range  

Science.gov (United States)

The possibility of measuring the three force components i.e. the main axial component and the two orthogonal radial components, generated by an electric propulsion system is important for two reasons. Firstly, to assess the impact of spacecraft/propulsion system integration issues, for example to verify the alignment of the thrust vector with the spacecraft centre-of-mass for spacecraft stability. Secondly, to operate the thruster properly during flight, for example to determine the thrust vector relative to the mechanical axis of the thruster. Furthermore, a three-axis measurement capability will be useful for the experimental performance verification of the next generation of vectored electric propulsion devices, especially regarding the many unresolved issues connected with indirect thrust measurement using electrostatic probes. The capability to monitor thrust vector drift in real time and with significant bandwidth is also important. Thus enabling vector drift during thruster warm-up, to be measured, and the response of vectored thrusters to change in vector demand can be assessed. In this paper we describe the design, construction and testing of an instrument proof of concept. The instrument was designed to accommodate a dummy thruster mass of 0.5 kg and operate in the 0 to 10 mN range. The directional resolution that has been demonstrated is better than 0.05 ° in both axes when operating at full thrust.

Hughes, B.; Oldfield, S.

2004-10-01

244

Engineering Research and Development and Technology thrust area report FY92  

International Nuclear Information System (INIS)

The mission of the Engineering Research, Development, and Technology Program at Lawrence Livermore National Laboratory (LLNL) is to develop the technical staff and the technology needed to support current and future LLNL programs. To accomplish this mission, the Engineering Research, Development, and Technology Program has two important goals: (1) to identify key technologies and (2) to conduct high-quality work to enhance our capabilities in these key technologies. To help focus our efforts, we identify technology thrust areas and select technical leaders for each area. The thrust areas are integrated engineering activities and, rather than being based on individual disciplines, they are staffed by personnel from Electronics Engineering, Mechanical Engineering, and other LLNL organizations, as appropriate. The thrust area leaders are expected to establish strong links to LLNL program leaders and to industry; to use outside and inside experts to review the quality and direction of the work; to use university contacts to supplement and complement their efforts; and to be certain that we are not duplicating the work of others. This annual report, organized by thrust area, describes activities conducted within the Program for the fiscal year 1992. Its intent is to provide timely summaries of objectives, theories, methods, and results. The nine thrust areas for this fiscal year are: Computational Electronics and Electromagnetics; Computational Mechanics; Diagnostics and Microelectronics; Emerging Technologies; Fabrication Technology; Materials Science and Engineering; Microwave and Pulsed Power; Nondestructive Evaluation; and Remote Sensing and Imaging, and Signal Engineering.

1993-01-01

245

Engineering Research and Development and Technology thrust area report FY92  

Energy Technology Data Exchange (ETDEWEB)

The mission of the Engineering Research, Development, and Technology Program at Lawrence Livermore National Laboratory (LLNL) is to develop the technical staff and the technology needed to support current and future LLNL programs. To accomplish this mission, the Engineering Research, Development, and Technology Program has two important goals: (1) to identify key technologies and (2) to conduct high-quality work to enhance our capabilities in these key technologies. To help focus our efforts, we identify technology thrust areas and select technical leaders for each area. The thrust areas are integrated engineering activities and, rather than being based on individual disciplines, they are staffed by personnel from Electronics Engineering, Mechanical Engineering, and other LLNL organizations, as appropriate. The thrust area leaders are expected to establish strong links to LLNL program leaders and to industry; to use outside and inside experts to review the quality and direction of the work; to use university contacts to supplement and complement their efforts; and to be certain that we are not duplicating the work of others. This annual report, organized by thrust area, describes activities conducted within the Program for the fiscal year 1992. Its intent is to provide timely summaries of objectives, theories, methods, and results. The nine thrust areas for this fiscal year are: Computational Electronics and Electromagnetics; Computational Mechanics; Diagnostics and Microelectronics; Emerging Technologies; Fabrication Technology; Materials Science and Engineering; Microwave and Pulsed Power; Nondestructive Evaluation; and Remote Sensing and Imaging, and Signal Engineering.

Langland, R.T.; Minichino, C. [eds.

1993-03-01

246

Hydrostatic bearings for a turbine fluid flow metering device  

Energy Technology Data Exchange (ETDEWEB)

A rotor assembly fluid metering device has been improved by development of a hydrostatic bearing fluid system which provides bearing fluid at a common pressure to rotor assembly bearing surfaces. The bearing fluid distribution system produces a uniform film of fluid between bearing surfaces and allows rapid replacement of bearing fluid between bearing surfaces, thereby minimizing bearing wear and corrosion.

Fincke, James R. (Rigby, ID)

1982-01-01

247

On the problem of optimal control of the thrust value of the electric propulsion rocket with solar energy source  

Science.gov (United States)

Under consideration is the optimal control problem on a spacecraft motion in Newtonian central gravity field. With the use of the mathematical model of electrojet propulsion device (EPD) with solar energy source, proposed earlier in paper [1], the dependence of the EPD working substance choice on both the duration of the given dynamic maneuver and the propellant expenditures for its fulfillment is investigated. The efficiency evaluation is carrying out of optimal control of variable valued thrust as well as that for relay mode thrust and relay mode thrust with optimal fixed thrust value.

Kiforenko, Boris N.; Vasil'ev, Igor Yu.; Tkachenko, Yaroslav V.

2013-08-01

248

Trajectories for missions of low-thrust spacecraft aimed at delivery of soil samples from main belt asteroids and Phobos  

Science.gov (United States)

Trajectories of spacecraft with electro-jet low-thrust engines are studied for missions planning to deliver samples of matter from small bodies of the Solar System: asteroids Vesta and Fortuna, and Martian moon Phobos. Flight trajectories are analyzed for the mission to Phobos, the limits of optimization of payload spacecraft mass delivered to it are determined, and an estimate is given to losses in the payload mass when a low-thrust engine with constant outflow velocity is used. The model of an engine with ideally regulated low thrust is demonstrated to be convenient for calculations and analysis of flight trajectories of a low-thrust spacecraft.

Akhmetshin, R. Z.; Efimov, G. B.; Eneev, T. M.

2009-02-01

249

Geometry and sequence of thrusting in the Alpine Foreland of western Austria and Bavaria  

Science.gov (United States)

Paleomagnetic data from all main external tectonic units of the Western part of the Eastern Alps indicate large vertical axis rotations between the undeformed (=foreland Molasse) and deformed foreland (= Subalpine Molasse), and between the Helvetic nappes and the Subalpine Molasse. Large rotations of large blocks can only be accommodated by thrust planes, as rotation between vertical faults would create major space problems. Differential rotations should be expressed in differential shortening across the Alpine thrusts. As available shortening estimates within the Subalpine Molasse are far too small to be compatible with paleomagnetic data, we re-examined several cross sections and tried to describe lateral changes in structural style and amount of shortening. From the most external to internal, following major structural zones have been identified: (1) A detachment fold on top of a triangle zone at depth, which is replaced by a foreland-facing fold without triangle zone to the east. (2) An eastward diminishing number of imbricates is superimposed out-of-sequence onto zone (1) and their basal thrust truncates the passive backthrust on top of the triangle zone. Locally, this thrust overturns the foreland-facing limb of the detachment fold. The thrust at the base of the southernmost slice systematically superimposes the deepest part of the foreland sequence onto intermediate parts. Seismic sections show that this slice sits on top of a major upper footwall flat and the northerly adjacent slice is a footwall imbricate. The footwall flat reaches far to the south beneath tectonically higher units, whereas the northern duplex slices are frontal hanging-wall imbricates of a major thrust sheet. Out-of-sequence thrusts dissecting the southernmost slice cut down to the basal detachment of Subalpine Molasse and stack older thrusts. A triangle zone forms the contact to the tectonically higher Helvetic and Flysch nappes, which is locally exposed but also indicated by wells. The age of triangle zone formation at the tectonic front of the Alps is constrained by southward wedging and onlap of Middle to Late Miocene (16-7 Ma) deposits against the triangle zone. Out-of-sequence thrusting of the northernmost imbricate onto the triangle zone marks the end of foreland propagation of thrusting and the onset of internal thickening of the orogenic wedge during the Tortonian. Apatite fission track dating in a well penetrating the southernmost Molasse slice in Eastern Switzerland revealed more than 1 km exhumation relative to the more northern slices postdating the Early Pliocene (4.7 Ma), which was related to thrusting (Cederbom et al., 2007). It shows that out-of-sequence thrusting started to propagate backward into the Alpine orogen in the Pliocene. CEDERBOM, C., SCHLUNEGGER, F., SINCLAIR, H. D. & VAN DER BEEK, P. (2007): What can the Swiss Molasse basin tell us about the Late Neogene development of the Alps?- Abstr. 8th WAGS Davos, 10-11, Bonn.

Ortner, H.; Thöny, W.; Aichholzer, S.; Zerlauth, M.; Pilser, R.; Tomek, C.

2009-04-01

250

Active blind thrusts beneath the Tokyo metropolitan area: Seismic hazards and inversion tectonics  

Science.gov (United States)

The Tokyo metropolitan area, underlain by Neogene and Quaternary sediments more than 5 km thick, is currently deformed by blind thrusts that could generate hazardous earthquakes. However, their little geomorphic expression and dense urbanization make understanding of folds produced above them and recent deformation highly elusive. Here we show subsurface geometries of several active blind thrusts beneath this highly urbanized area, based on tectonic landforms, high-resolution seismic reflection data, and Quaternary stratigraphy. Deep seismic reflection profiles corroborate the notion that steeply dipping blind thrusts are reactivated normal faults originally formed by middle Miocene extensional tectonics. Despite very slow (less than 0.1 mm/yr) late Quaternary slip rates, our work suggests the presence of previously unrecognized faults that pose seismic hazards to Tokyo and outlying communities, highlighting the need for additional information to define recent slip rates, magnitude, and recurrence of past earthquakes on them.

Ishiyama, Tatsuya; Sato, Hiroshi; Kato, Naoko; Nakayama, Toshio; Abe, Susumu

2013-06-01

251

Feedback Optimal Control of Low-thrust Orbit Transfer in Central Gravity Field  

Directory of Open Access Journals (Sweden)

Full Text Available Low-thrust trajectories with variable radial thrust is studied in this paper. The problem is tackled by solving the Hamilton- Jacobi-Bellman equation via State Dependent Riccati Equation( STDE) technique devised for nonlinear systems. Instead of solving the two-point boundary value problem in which the classical optimal control is stated, this technique allows us to derive closed-loop solutions. The idea of the work consists in factorizing the original nonlinear dynamical system into a quasi-linear state dependent system of ordinary differential equations. The generating function technique is then applied to this new dynamical system, the feedback optimal control is solved. We circumvent in this way the problem of expanding the vector field and truncating higher-order terms because no remainders are lost in the undertaken approach. This technique can be applied to any planet-to-planet transfer; it has been applied here to the Earth-Mars low-thrust transfer

Ashraf H. Owis

2013-01-01

252

Optimal design of thrust force in vertical-type HTS bulk LRM  

International Nuclear Information System (INIS)

[en] We proposed the vertical-type linear reluctance motor (LRM) with HTS bulks cooled in zero-field. The double-sided HTS bulk LRM is propelled contactlessly only by electromagnetic repulsive force from both sides of a double-sided armature guideway. This paper presents optimal thrust force design based on the dependence of thrust on the size of HTS bulk attached to the cage in vertical-type HTS bulk LRM. The thrust force is calculated by Finite Element Method (FEM), taking into account the E-J characteristic. Improved HTS bulk LRM which is 1.5 times heavier than the previous cage can be propelled contactlessly in propulsion and guidance simulation

2005-10-01

253

Research on a thrust control device for side thrusters; Side thruster suiryoku seigyo sochi no kenkyu  

Energy Technology Data Exchange (ETDEWEB)

The advancement in missile flight control technology in recent years has been remarkable. As a specific example, the use of control methods such as thrust vector control (TVC) and side thrusters to replace conventional aerodynamic control has become practicable. Even in the upper altitude zone where air density is low, sufficient maneuverability may be obtained from side thrusters. This technique has ,therefore, particularly been adopted in missiles designed to intercept ballistic missiles. Research is now under way into the practical application of a new method of side thruster control, which facilitates thrust control by changing the throat area. In this paper, the restrained firing tests (RFTs) conducted at the Gifu factory from 1998 through 1999 to validate the heat resistance and thrust characteristics of our new side thruster are reported. (author)

Nishikawaa, T.; Waki, H.; Harada, K.; Kato, H. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

2000-04-01

254

Geology of oil and gas accumulations in the Papuan fold and thrust belt  

Energy Technology Data Exchange (ETDEWEB)

The high level of exploration interest in Papua New Guinea has developed in large part because of recent discoveries in the western Papuan fold and thrust belt and shows in the adjacent foreland region. Results from recent drilling in the Iagifu/Hedinia area by a Chevron-led joint venture have outlined several pools in culminations along a 50 km long structural axis. Oil and gas are sourced from a thick succession of Jurassic marine shales that were deposited along the rifted northern margin of the Australian plate. Generation and migration is interpreted to have peaked coincident with development of the fold and thrust belt during the Neogene. Trapping occurred as anticlines and thrust sheets developed sequentially from northeast to southwest. Several trends remain untested on lands held by various groups, primarily in the area west of the Juha gas condensate pool.

Foo, W.K. (Chevron Overseas Petroleum, Inc., San Ramon, CA (USA))

1990-06-01

255

Thermal effects of overthrusting, Little Mountains thrust belt, eastern New York  

Energy Technology Data Exchange (ETDEWEB)

Thermal models constrained by clay mineral assemblages, vitrinite reflectance, and palinspatic restoration are used to interpret the thermal history of the Appalachian thrust belt of eastern New York. The deformed Appalachian foreland of eastern New York is comprised of two adjacent north-south-trending thrust belts: (1) the Taconic Mountains, allochthons emplaced during the Late Ordovician Taconic orogeny; and (2) Little Mountains thrust belt, faulted and folded Lower Devonian carbonates exhibiting well-developed solution cleavage, deformed during the Devonian Acadian or Pennsylvanian Alleghenian orogeny. Conodont alteration index from the Little Mountains range from 4.0 to 4.5, suggesting temperatures of 190/sup 0/-240/sup 0/C. This thermal imprint may be attributed to burial heating from 8 km of post-Lower Devonian molasse in the Catskill Mountains, whose present thickness is 2.3 km. Elevated temperature-pressure conditions resulting from an overriding thrust sheet would facilitate formation of solution cleavage in the Little Mountains, in a manner similar to that demonstrated in the Idaho-Wyoming thrust belt. X-ray analysis of clay minerals from Catskill shales in the undeformed foreland show: (1) there is little or no discrete smectite; (2) illite predominates, with illite peaks being asymmetric toward lower 28 suggesting a minor component of random interstratified illite-smectite; and (3) illite has decreasing crystallinity with increasing burial depth. These results indicate sedimentary overburden has had little effect on illite crystallinity, as crystallinity should systematically increase with increasing temperatures (i.e., increasing depth). Catskill illites exhibiting decreasing crystallinites may reflect that they are detrital and are derived from progressive erosion of a Taconic thrust sheet, resulting in an inverted illite stratigraphy.

Zadins, Z.; Mitra, G.

1986-05-01

256

Structural Discordance Between Neogene Detachments and Frontal Sevier Thrusts, Central Mormon Mountains, Southern Nevada  

Science.gov (United States)

Detailed geologic mapping in the Mormon Mountains of southern Nevada provides significant insight into processes of extensional tectonics developed within older compressional orogens. A newly discovered, WSW-directed low-angle normal fault, the Mormon Peak detachment, juxtaposes the highest levels of the frontal most part of the east-vergent, Mesozoic Sevier thrust belt with autochthonous crystalline basement. Palinspastic analysis suggests that the detachment initially dipped 20-25° to the west and cut discordantly across thrust faults. Nearly complete lateral removal of the hanging wall from the area has exposed a 5 km thick longitudinal cross-section through the thrust belt in the footwall, while highly attenuated remnants of the hanging wall (nowhere more than a few hundred meters thick) structurally veneer the range. The present arched configuration of the detachment resulted in part from progressive "domino-style" rotation of a few degrees while it was active, but is largely due to rotation on younger, structurally lower, basement-penetrating normal faults that initiated at high-angle. The geometry and kinematics of normal faulting in the Mormon Mountains suggest that pre-existing thrust planes are not required for the initiation of low-angle normal faults, and even where closely overlapped by extensional tectonism, need not function as a primary control of detachment geometry. Caution must thus be exercised in interpreting low-angle normal faults of uncertain tectonic heritage such as those seen in the COCORP west-central Utah and BIRP's MOIST deep-reflection profiles. Although thrust fault reactivation has reasonably been shown to be the origin of a very few low-angle normal faults, our results indicate that it may not be as fundamental a component of orogenic architecture as it is now widely perceived to be. We conclude that while in many instances thrust fault reactivation may be both a plausible and attractive hypothesis, it may never be assumed.

Wernicke, Brian; Walker, J. Douglas; Beaufait, Mark S.

1985-02-01

257

Axial-thrust responses due to a gas turbine's rotor blade distortions  

Science.gov (United States)

The axial thrust imposed on the shaft of a gas turbine depends upon its rotor blade inlet inclination to the turbine's axial direction: this inclination can change due to the distortions resulting from fouling, aging, tip rubbing, erosion, thermal-fatigue cracks, and corrosion. Relevant influential parameters for an operational gas turbine were measured. Theoretical predictions for the behavior of the same turbine were obtained from computer simulations. The results of both measurements and theoretical predictions were compared and showed qualitative correspondence. The rotor blade profile distortions result in significant increases in the axial thrust on the compressor, which adversely affects the gas turbine's thermodynamic performance, reliability, and operational life.

Lebele-Alawa, B. T.

2010-11-01

258

A reevaluation of the age of the Vincent-Chocolate Mountains thrust system, southern California  

Energy Technology Data Exchange (ETDEWEB)

The Vincent-Chocolate Mountains (VCM) thrust superposes Mesozoic arc plutons and associated Precambrian country rock above subduction-related Pelona-Orocopia schist. The thrust is disrupted in many areas by postmetamorphic deformation, but appears to be intact in the San Gabriel Mountains. Two Rb-Sr mineral-isochron ages from Pelona Schist and mylonite in the San Gabriel Mountains led Ehlig (1981) to conclude that the original thrusting event occurred at c. 60 Ma. However, biotite K-Ar ages determined by Miller and Morton (1980) for upper plate in the same area caused Dillon (1986) to reach a different conclusion. The biotite ages range mainly from 74--60 Ma and increase structurally upward from the VCM thrust. Dillon (1986) inferred that the age gradient was due to uplift and cooling of the upper plate during underthrusting of Pelona Schist. This would indicate that the VCM thrust was at least 74 Ma in age. An alternative to the interpretation of Dillon (1986) is that the biotite age gradient largely predates the VCM thrust. Upward heat flow, leading to older ages at higher structural levels, could have resulted from either static cooling of Cretaceous plutons or uplift and erosion induced by crustal thickening during possible west-directed intra-arc thrusting at c. 88--78 Ma (May and Walker, 1989). Subsequent underthrusting of Pelona Schist would establish a cold lower boundary to the crust and cause the closure of isotopic systems in the base of the upper plate. A 60 Ma time of thrusting is also suggested by two amphibole [sup 40]Ar/[sup 39]Ar ages from the Pelona Schist of the San Gabriel Mountains. Peak metamorphic temperature in this area was below 480 C and amphibole ages should thus indicate time of crystallization rather than subsequent cooling. Four phengite [sup 40]Ar/[sup 39]Ar ages of 55--61 Ma from Pelona Schist and mylonite indicate rapid cooling from peak metamorphic temperatures, consistent with subduction refrigeration.

Jacobsen, C.E. (Iowa State Univ., Ames, IA (United States). Dept. of Geological and Atmospheric Sciences); Barth, A.P. (Indiana Univ.--Purdue Univ., Indianapolis, IN (United States). Dept. of Geology)

1993-04-01

259

3D evolution of fold and thrust belts formed by oblique convergence  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the results of a series of scaled analogue models designed to simulate thrust belt development formed by orthogonal and oblique convergence. The models were constructed to produce doubly-vergent orogenic wedges with a pro-wedge and a retro-wedge separated by an uplifted orogenic core. Models were constructed from homogeneous layered sandpacks in a 3 m x 1.3 m deformation rig. The progressive evolution of the models was recorded using digital photography, and the photographs were animated for analysis. The experiments investigated convergence obliquities from orthogonal (90{sup o}) to as low as 15{sup o} obliquity. Orthogonal models produced long, linear, critically tapered pro-wedge fold and thrust belts parallel to the convergence margin together with a narrow, uplifted core and a steep retro-wedge thrust system. The taper angle of the pro-wedge was typically 11-12{sup o} whereas the retro-wedge maintained a steeper taper of 38-42{sup o}. Models where the convergence vector was oblique at angles of 60 and 45{sup o} to the margin produced doubly-vergent thrust wedges with thrust faults trending parallel to the margin. There was little evidence of linked, penetrative strike-slip faulting but en-echelon Riedel like shear systems developed in the 45{sup o} oblique model. Subordinate oblique-slip motion was observed on some thrust faults. In contrast, for 30 and 15{sup o} oblique convergence models, strong deformation partitioning developed with steeply sloping pro-wedges that did not have critical tapers. Through-going linked strike-slip faulting was developed that cut the uplifted axial zones of these models. Analysis of the models by animation of the digital photographs shows how the thrust systems initiated and propagated. In particular it is clear that at any one time several thrusts were moving simultaneously. Serial cross sections through the moderately oblique convergence models (60-45{sup o}) are almost indistinguishable from the orthogonal model cross-sections. The results of orthogonal convergence experiments compare well to the map patterns of faults and folds in the Salt Range, Pakistan. 60 and 45{sup o} oblique convergence models compare well to the Zagros where some strain partitioning on strike-slip faults occurs. The highly oblique models show very strong strain partitioning with penetrative margin-parallel strike-slip faulting similar to that found in NE Venezuela. (author)

McClay, K.R.; Whitehouse, P.S.; Dooley, T.; Richards, M. [University of London, Egham (United Kingdom). Fault Dynamics Research Group

2004-08-01

260

The Chi-Chi Earthquake Sequence: Active, Out-of-Sequence Thrust Faulting in Taiwan  

Science.gov (United States)

We combined precise focal depths and fault plane solutions of more than 40 events from the 20 September 1999 Chi-Chi earthquake sequence with a synthesis of subsurface geology to show that the dominant structure for generating earthquakes in central Taiwan is a moderately dipping (20° to 30°) thrust fault away from the deformation front. A second, subparallel seismic zone lies about 15 kilometers below the main thrust. These seismic zones differ from previous models, indicating that both the basal decollement and relic normal faults are aseismic.

Kao, Honn; Chen, Wang-Ping

2000-06-01

 
 
 
 
261

Seismic interpretation and thrust tectonics of the Amadeus Basin, central Australia, along the BMR regional seismic line  

Science.gov (United States)

At the northern margin of the Amadeus Basin the monoclinal upturn (the MacDonnell Homocline) is interpreted to be the result of rotation and limited back-thrusting of the sedimentary sequence in front of a southerly-directed, imbricate basement thrust-wedge. This thrust complex is linked at depth to the crust-cutting Redbank Thrust Zone. In the northern part of the basin immediately to the south, regional seismic reflection profiling across the Missionary Plain shows a sub-horizontal, north-dipping, parautochthonous sedimentary sequence between about 8.5 km and 12.0 km thick. This sedimentary sequence shows upturning only at the northern and southern extremities, and represents an unusual, relatively undeformed region between converging thrust systems. In this intervening region, the crust appears to have been tilted downwards and northwards in response to the upthrusting to the north. Still farther to the south, the vertical uplift of the southern hanging wall of the Gardiner Thrust is about 6 km. Seismic reflection profiling in the region immediately south of the Gardiner Thrust indicates repetition of the sedimentary sequence. At the far end of the profile, in the Kernot Range, an imbricate thrust system fans ahead of a ramp-flat thrust pair. This thrust system (the Kernot Range Thrust System) occurs immediately north of an aeromagnetic domain boundary which marks the southern limit of a central ridge region characterized by thin Palaeozoic sedimentary cover and shallow depths to magnetic basement. A planar seismic event, imaged to a depth of at least 18 km, may correspond to the same boundary and is interpreted as a pre-basin Proterozoic thrust. Overall, the structure in the shallow sedimentary section in the central-southern region of the Amadeus Basin indicates that north-directed thrusting during the Dovonian-Carboniferous Alice Springs Orogeny was thin-skinned. During this orogeny an earlier thrust system, formed during the Petermann Ranges Orogeny and precursor orogenies in the Late Proterozoic, was reactivated with Proterozoic salt deposits localising the decollement zone. The Alice Springs Orogeny also reactivated a major mid Proterozoic province boundary in the basement to the north of the basin, resulting in major thrust movement at the northern basin margin.

Shaw, Russell D.; Korsch, Russell J.; Wright, C.; Goleby, B. R.

262

Wave journal bearing. Part 1: Analysis  

Energy Technology Data Exchange (ETDEWEB)

A wave journal bearing concept features a waved inner ring diameter 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 the applied 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.

Dimofte, F. [Univ. of Toledo, Cleveland, OH (United States)

1995-12-31

263

Detachments in Shale: Controlling Characteristics on Fold-Thrust Belt Style  

Science.gov (United States)

Fold-thrust belts occur across multiple tectonic settings where thin-skinned deformation is accommodated by one or more detachment zones, both basal and within the fold-thrust belt. These fold-thrust belts exhibit considerable variation in structural style and vergence depending on the characteristics (e.g. strength, thickness, and lithology) and number of detachment zones. Shale as a detachment lithology is intrinsically weaker than more competent silts and sands; however, it can be further weakened by high pore pressures, reducing resistance to sliding and; high temperatures, altering the rheology of the detachment. Despite the implications for petroleum exploration and natural hazard assessment the precise nature by which detachments in shale control and are involved in deformation in fold-thrust belts is poorly understood. Present-day active basal detachment zones are usually located in inaccessible submarine regions. Therefore, this project employs field observations and sample analysis of ancient, exhumed analogues to document the nature of shale detachments (e.g. thickness, lithology, dip and dip direction, deformational temperature and thrust propagation rates) at field sites in Thailand, Norway and New Zealand. X-ray diffraction analysis of illite crystallinity and oxygen stable isotopes analysis are used as a proxy for deformational temperature whilst electron-backscatter diffraction analysis is used to constrain microstructural deformational patterns. K-Ar dating of synkinematic clay fault gouges is being applied to date the final stages of activity on individual faults with a view to constraining thrust activation sequences. It is not possible to directly measure palaeo-data for some key detachment parameters, such as pore pressure and coefficients of friction. However, the use of critical taper wedge theory has been used to successfully infer internal and basal coefficients of friction and depth-normalized pore pressure within a wedge and at its base (e.g. Platt, 1986; Bilotti and Shaw, 2005; Morley, 2007). Therefore, through a mixture of field observations, sample analysis and theoretical analysis it will be possible to determine a full range of shale detachment parameters and their impact on the structural style of fold-thrust belts across a variety of settings. Recent work in Muak Lek, central Thailand has focused on a structural investigation of fold-thrust belt deformation of a passive margin sequence as a result of continent-continent collision during the Triassic Indosinian Orogeny. Exceptional outcropping of the detachment lithology is accessible in the Siam City Cement quarry allowing construction of sections detailing the deformational style across the detachment itself. The detachment forms complex, 3-dimensional duplex-like structures creating egg-carton geometries enveloping foliation surfaces in the zones of most intense strain. Up section strain decreases to discrete thrust imbricates of decametre scale. Samples of limestone and secondary calcite were collected through the sections for oxygen stable isotopes analysis which show a distinct pattern of isotopic fractionation across the main thrust and into the detachment. Results from this study give insights into the nature of shale detachments and the control on fold-thrust belt development.

Hansberry, Rowan; King, Ros; Collins, Alan; Morley, Chris

2013-04-01

264

Bradycardia of the Polar Bear.  

Science.gov (United States)

For several years two male polar bears have been studied by long-life implanted physiological radio capsules at the Naval Arctic Research Laboratory, at Point Barrow. A regular measurement has been the resting heart rate; for this we used the lowest heart...

G. E. Folk J. J. Berberich D. K. Sanders

1973-01-01

265

Beth Starts Like Brown Bear!  

Science.gov (United States)

|Recounts a reading teacher's illuminating experience with a first grader who enjoyed reading Bill Martin's "Brown Bear" books, despite being labeled as dyslexic. Dyslexia is an elusive condition that is biological in origin and distinct from other reading problems. New research shows that reading difficulties, including dyslexia, occur as part of…

Fawcett, Gay

1994-01-01

266

Robust and intelligent bearing estimation  

Energy Technology Data Exchange (ETDEWEB)

As the monitoring thresholds of global and regional networks are lowered, bearing estimates become more important to the processes which associate (sparse) detections and which locate events. Current methods of estimating bearings from observations by 3-component stations and arrays lack both accuracy and precision. Methods are required which will develop all the precision inherently available in the arrival, determine the measurability of the arrival, provide better estimates of the bias induced by the medium, permit estimates at lower SNRs, and provide physical insight into the effects of the medium on the estimates. Initial efforts have focused on 3-component stations since the precision is poorest there. An intelligent estimation process for 3-component stations has been developed and explored. The method, called SEE for Search, Estimate, and Evaluation, adaptively exploits all the inherent information in the arrival at every step of the process to achieve optimal results. In particular, the approach uses a consistent and robust mathematical framework to define the optimal time-frequency windows on which to make estimates, to make the bearing estimates themselves, and to withdraw metrics helpful in choosing the best estimate(s) or admitting that the bearing is immeasurable. The approach is conceptually superior to current methods, particular those which rely on real values signals. The method has been evaluated to a considerable extent in a seismically active region and has demonstrated remarkable utility by providing not only the best estimates possible but also insight into the physical processes affecting the estimates. It has been shown, for example, that the best frequency at which to make an estimate seldom corresponds to the frequency having the best detection SNR and sometimes the best time interval is not at the onset of the signal. The method is capable of measuring bearing dispersion, thereby withdrawing the bearing bias as a function of frequency. The lowest measurable frequency in the dispersion pattern is often a near error free bearing. These latter features should be helpful in calibrating the stations for frequency dependent biases induced by the earth. Future efforts will enhance the SEE algorithm and will also evaluate it using larger station data sets.

Claassen, J.P.

1998-07-01

267

The Thrust Plate Prosthesis: long-term clinical and radiological results.  

UK PubMed Central (United Kingdom)

The Thrust Plate Prosthesis is a femoral implant designed for total hip arthroplasty, based on the principles of physiologic loading of the metaphysis of the proximal femur, and preserving the bone stock. This study presents the long-term clinical and radiological results of 34 patients with 36 Thrust Plate Prostheses. In a retrospective analysis, we investigated the reoperation-free survival as well as the clinical and radiological results. Mean age at operation was 51 +/- 6.4 years. Mean follow-up length was 11.9 +/- 1.6 years. Reoperation-free survival was 88.9%. Four (11.1%) reoperations were performed, in three patients due to aseptic loosening and in one patient because of a fracture distal to the lateral plate. Three of the reoperations were performed between 12 and 32 months postoperatively. The major complaint was pain at the lateral side of the hip (44%). Radiolucencies did not exceed 1 mm, but 35% of the hips showed resorption of the cortex directly under the thrust plate, together with cancellous bone hypertrophy at the calcar, noted in 97%. Because of the relatively high reoperation-free survival and favourable radiological results, the Thrust Plate Prosthesis appears as a possible alternative to stemmed total hip arthroplasty, especially in relatively young patients.

Diederix LW; Van Winterswijk PJ; Schouten SB; Bakx PA; Huij J

2013-06-01

268

The Thrust Plate Prosthesis: long-term clinical and radiological results.  

Science.gov (United States)

The Thrust Plate Prosthesis is a femoral implant designed for total hip arthroplasty, based on the principles of physiologic loading of the metaphysis of the proximal femur, and preserving the bone stock. This study presents the long-term clinical and radiological results of 34 patients with 36 Thrust Plate Prostheses. In a retrospective analysis, we investigated the reoperation-free survival as well as the clinical and radiological results. Mean age at operation was 51 +/- 6.4 years. Mean follow-up length was 11.9 +/- 1.6 years. Reoperation-free survival was 88.9%. Four (11.1%) reoperations were performed, in three patients due to aseptic loosening and in one patient because of a fracture distal to the lateral plate. Three of the reoperations were performed between 12 and 32 months postoperatively. The major complaint was pain at the lateral side of the hip (44%). Radiolucencies did not exceed 1 mm, but 35% of the hips showed resorption of the cortex directly under the thrust plate, together with cancellous bone hypertrophy at the calcar, noted in 97%. Because of the relatively high reoperation-free survival and favourable radiological results, the Thrust Plate Prosthesis appears as a possible alternative to stemmed total hip arthroplasty, especially in relatively young patients. PMID:23926732

Diederix, Leon W; Van Winterswijk, Peter J T S; Schouten, Sander B; Bakx, Pieter A G M; Huij, Jaap

2013-06-01

269

The Cenozoic structural evolution of a fold-and-thrust belt, northeastern Brooks Range, Alaska  

Energy Technology Data Exchange (ETDEWEB)

A Cenozoic fold-and-thrust belt in the eastern structural province of the northeastern Brooks Range exposes polydeformed low-grade metasedimentary and metavolcanic rocks of the pre-Mississippian basement and its sedimentary cover immediately adjacent to much younger foredeep deposits. Analysis of mesoscopic and map-scale structures in the range-front region suggests that at least one pre-Mississippian deformational event was recorded into the basement sequence by north-vergent fold-and-thrust structures and associated penetrative structures. Most of later Cenozoic shortening of the pre-Mississippian rocks was accommodated by thrust duplication, with little development of penetrative mesoscopic structures. Although separated from the underlying basement rocks by a major regional decollement horizon, Cenozoic deformation in the overlying Mississippian through Lower Cretaceous cover sequence also was primarily by thrust duplication. Although local and regional structural trends within the cover sequence suggest that Cenozoic deformation was north-northwest directed, east-west Cenozoic structural trends within the pre-Mississippian rocks may reflect an inherited pre-Mississippian structural grain and/or pre-Mississippian-age structures reactivated during Cenozoic deformation. A regional balanced cross section of the eastern structural province was constructed. 29 refs., 14 figs.

Hanks, C.L. (Univ. of Alaska, Fairbanks (United States))

1993-03-01

270

Cyclical behavior of thrust wedges: Insights from high basal friction sandbox experiments  

Science.gov (United States)

Scaled sandbox experiments with high basal friction, simulating the growth of accretionary wedges, display cycles alternating between frontal imbricate thrusting and underthrusting of long, undeformed sheets. By contrast, low basal friction experiments with otherwise similar and constant, initial conditions produce a classic frontal imbricate fan through repeated failure along frontal thrusts. The cyclical behavior observed in high basal friction experiments is expressed by three quantities: (1) the average spacing between frontal thrusts, (2) the advance and retreat of the deformation front, and (3) the frontal slope (Alpha) of the actively deforming wedge. As a long sheet is underthrust, the front is steepened through slumping until the maximum critical angle is reached. Then frontal thrusting resumes and the accretion of imbricate slices builds the wedge forward, thereby lowering the taper to the minimum critical angle. At shallow tapers, a long unit is underthrust and subsequently uplifts, shortens, and steepens the overlying wedge through backthrust deformation, thus completing the cycle. Underthrusting of long units offers a simple mechanism for underplating overlying units. It also provides a possible explanation for temporally and spatially varying wedge geometries in nature, when basal frictions attain 80% 90% of the internal friction.

Gutscher, Marc-André; Kukowski, Nina; Malavieille, Jacques; Lallemand, Serge

1996-02-01

271

Reynolds Number Effects on Thrust Coefficients and PIV for Flapping Wing Micro Air Vehicles.  

Science.gov (United States)

For the last several years the Air Force Institute of Technology (AFIT) has conducted research in aerodynamics for flapping wing micro air vehicles (MAVs). The focus of this research was to augment this effort by measuring thrust, velocity, and torque in ...

J. P. Tekell

2012-01-01

272

Simultaneous thrust vector control and vibration isolation of satellites using steerable smart platforms  

Science.gov (United States)

This paper presents an innovative concept, control strategies and experimental verification of simultaneous thrust vector control and vibration isolation of satellites. First, the innovative concept is introduced by employing a smart platform as an active structural interface between the main thruster of a satellite and the satellite structure. Second, the inverse kinematics and singularity analysis of the smart platform are performed. Third, thrust vector control model of satellites with smart platforms is deduced. Fourth, a multiple loop control strategy is proposed. It includes three cascaded feedback loops for nonlinear compensation of actuators, smart platform control and trust vector control, respectively, and a combined feedback-feedforward control scheme for vibration isolation. Finally, experiments are carried out and experimental results are illustrated and discussed. The cascaded multiple feedback loops compensate the hysteresis (for piezoelectric stacks inside the three linear actuators that individually have simultaneous precision positioning and vibration suppression), dead-zone, back-lash, and friction nonlinearities very well, and provide precision and quick smart platform control and satisfactory thrust vector control capability. The experimental results demonstrate that the simultaneous thrust vector control and vibration suppression is achieved with satisfactory performance.

Ghasemi-Nejhad, Mehrdad N.; Ma, Kougen

2010-03-01

273

Syntectonic sedimentation effects on the growth of fold-and-thrust belts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We use two-dimensional mechanical models to investigate the effects of syntectonic sedimentation on fold-and-thrust belt development, testing variable syntectonic (wedge-top and foredeep) sediment thicknesses and flexural rigidities. Model results indicate a first-order control of syntectonic sedime...

Fillon, Charlotte; Huismans, Ritske; Van Der Beek, Pieter

274

Seafloor expression and shallow structure of a fold-and-thrust system, Isfjorden, west Spitsbergen  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A detailed map of the structure of the west Spitsbergen fold-and-thrust belt in the Isfjorden area, Spitsbergen, is presented. The map was constructed from a dense grid of two-dimensional multichannel reflection seismic and bathymetric data. Joint interpretation of two data sets allowed a comparison...

Maria Blinova; Jan Inge Faleide; Roy H. Gabrielsen; Rolf Mjelde

275

14 CFR 25.1155 - Reverse thrust and propeller pitch settings below the flight regime.  

Science.gov (United States)

...propeller pitch settings below the flight regime. 25.1155 Section 25.1155 Aeronautics...propeller pitch settings below the flight regime. Each control for reverse thrust and...propeller pitch settings below the flight regime must have means to prevent its...

2009-01-01

276

Study on development of ejector of Bubble Jet Engine (BJE) - measurement of thrust -  

International Nuclear Information System (INIS)

The AUV (Autonomous Under-water Vehicle), which is used for the present seabed investigations, has obtained the thrust with the screw driven by the battery. However, it has a disadvantage because of its size and cost. Therefore, this research is carried out to propose the Bubble Jet Engine (BJE) as an alternative propulsion device. It can directly transform combustion energy into kinetic energy, so it is expected that BJE can also rise the level of propulsion efficiency. This research aims at measuring exhaled mass flow rate and thrust to design ejectors, which become the core of BJE, and exploring practical possibility of BJE. Vertical type gas-water ejector experimental apparatus for measuring water entrainment was employed in order to understand the characteristics of operation conditions, such as inlet distance, air pressure of nozzle, diameter of nozzle, and so on. In addition, experiments for measuring the thrust in the condition of ejector were executed with horizontal type apparatus in water. However, the influence of the ejector to improve thrust can't have been recognized with high-pressure air at room temperature yet.

2009-02-01

277

Study on development of ejector of Bubble Jet Engine (BJE) - measurement of thrust -  

Energy Technology Data Exchange (ETDEWEB)

The AUV (Autonomous Under-water Vehicle), which is used for the present seabed investigations, has obtained the thrust with the screw driven by the battery. However, it has a disadvantage because of its size and cost. Therefore, this research is carried out to propose the Bubble Jet Engine (BJE) as an alternative propulsion device. It can directly transform combustion energy into kinetic energy, so it is expected that BJE can also rise the level of propulsion efficiency. This research aims at measuring exhaled mass flow rate and thrust to design ejectors, which become the core of BJE, and exploring practical possibility of BJE. Vertical type gas-water ejector experimental apparatus for measuring water entrainment was employed in order to understand the characteristics of operation conditions, such as inlet distance, air pressure of nozzle, diameter of nozzle, and so on. In addition, experiments for measuring the thrust in the condition of ejector were executed with horizontal type apparatus in water. However, the influence of the ejector to improve thrust can't have been recognized with high-pressure air at room temperature yet.

Ono, B; Nakashima, K; Shigematsu, T; Morishita, K, E-mail: ono@post.cc.sasebo.ac.j [Sasebo National College of Technology1-1, Okishin-cho, Sasebo City, Nagasaki Pref., 857-1193 (Japan)

2009-02-01

278

Influence of ancient thrust faults on the hydrogeology of the Blue Ridge Province.  

UK PubMed Central (United Kingdom)

The Blue Ridge Province contains ubiquitous northeast-southwest-trending thrust faults or smaller thrust "slivers" that greatly impact the nature and character of ground water flow in this region. Detailed investigations at a field site in Floyd County, Virginia, indicate that high-permeability zones occur in the brittle crystalline rocks above these thrust faults. Surface and borehole geophysics, aquifer tests, and chlorofluorocarbon and geochemical data reveal that the shallow saprolite aquifer is separated from the deeper fault-zone aquifer by a low-fracture permeability bedrock confining unit, the hydraulic conductivity of which has been estimated to be six orders of magnitude less than the conductivity of the fault zones at the test site. Within the Blue Ridge Province, these fault zones can occur at depths of 300 m or more, can contain a significant amount of storage, and yield significant quantities of water to wells. Furthermore, it is expected that these faults may compartmentalize the deep aquifer system. Recharge to and discharge from the deep aquifer occurs by slow leakage through the confining unit or through localized breach zones that occur where quartz accumulated in high concentrations during metamorphism and later became extensively fractured during episodes of deformation. The results of this investigation stress the importance of thrust faults in this region and suggest that hydrogeologic models for the Blue Ridge Province include these ancient structural features. Faults in crystalline-rock environments may not only influence the hydrology, they may dominate the flow characteristics of a region.

Seaton WJ; Burbey TJ

2005-05-01

279

Predicting stress distributions in fold-and-thrust belts and accretionary wedges by optimization  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The objective is to demonstrate that the equilibrium element method (EEM) provides the stress distribution in geometrical models of folds, relevant to fold-and-thrust belts as well as accretionary wedges. The core of the method, inherited from limit analysis, is the search for an optimum stress fiel...

Souloumiac, P.; M. Leroy, Y.; Maillot, B.; Krabbenhøft, K.

280

Style, magnitude, and timing of shortening at the eastern end of Kura fold-thrust belt, Azerbaijan  

Science.gov (United States)

Although the Greater Caucasus forms the northern edge of the Arabia-Eurasia collision, the main locus of shortening has shifted south since 5 Ma, producing the Kura fold-thrust belt in Georgia and Azerbaijan. Eastward-decreasing structural complexity and depth of exposure within the thrust belt suggest eastward propagation of faulting. Two topographic features define the eastern termination of the Kura fold-thrust belt at ~48°E: a southern range front exposing south-directed, closely spaced (< 5 km) thrusts and folds deforming sediments of Apsheron (1.6-0.7 Ma) and Baku-Khazar (0.7-0.3 Ma) ages and a northern range of hills with virtually no exposure of underlying bedrock, previously suggested to be the product of a north-vergent back thrust. To determine the style, magnitude, and timing of shortening at the east end of the fold-thrust belt, we conducted 1:100K-scale structural mapping covering ~1000 ~km^2 of this region. Along-strike changes in structural geometry divide the map area into two structural domains, the Surxayxan in the west and the Qaramaryam to the east. The Surxayxan domain (47.5°E to 47.8°E) is characterized by two main, north-dipping thrusts, the Savalan to the north and Agcayazi ~4-6 km to the S. At maximum displacement the Savalan thrust places Apsheron sediments over Baku-Khazar deposits, repeating ~2 km of section. The hanging wall anticline of the Savalan thrust is poorly preserved, but a footwall syncline occurs along its full length. The Agcayazi thrust defines the southern range front in this domain, characterized by exposures of Apsheron sediments with the overturned forelimb of the hanging wall anticline preserved in limited areas, but no definitive exposure of the thrust. The Qaramaryam structural domain (47.8°E to 48.3°E) is characterized by the eastwards termination of the Agcayazi thrust and transfer of slip to the north-dipping Padar and Inca thrusts to the south, which together form the Qaramaryam anticline. The latter two thrusts are separated by ~4 km and expose the top of the Apsheron at their maximum displacements but mostly deform Baku-Khazar sediments. In both domains, fold geometries are consistent with a trishear model. Preliminary balanced cross sections across the Surxayxan region suggest ~10 km of total shortening. The simplest structural geometry for the Surxayxan region suggests that the Savalan thrust is out of sequence and younger than the Agcayazi thrust. Based on field observations within both domains, we assume that the topographic surface of the N structural system serves as a deformed marker and can be effectively described by either a kink generated over a ramp down dip from the Savalan thrust or a small blind S vergent thrust, but not cannot be reproduced with a N vergent structure (back thrust). Assuming shortening began at the end of the Apsheron (0.7 Ma) implies an average shortening rate of ~14 mm/yr at the E end of the Kura fold-thrust belt.

Forte, A. M.; Cowgill, E.; Murtuzayev, I.

2010-12-01

 
 
 
 
281

Trends in Controllable Oil Film Bearings  

DEFF Research Database (Denmark)

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

Santos, Ilmar Technical University of Denmark,

2011-01-01

282

An Analysis of the Viscoseal Bearing.  

Science.gov (United States)

The purpose of this investigation was to evaluate the use of a method of predicting the load carrying capacity and attitude angle of the viscoseal bearing and to devise a more accurate method of analyzing the bearing. (Author)

W. L. Roberts

1969-01-01

283

Mercury in polar bears from Alaska  

Energy Technology Data Exchange (ETDEWEB)

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

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

1987-04-01

284

Thin film superconductor magnetic bearings  

Energy Technology Data Exchange (ETDEWEB)

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.

Weinberger, Bernard R. (Avon, CT)

1995-12-26

285

Nonlinear Dynamic Response of Compliant Journal Bearings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper investigates the dynamic response of the compliant tilting pad journal bearings subjected to synchronous excitation. Bearing compliance is affected by the properties of pad liner and pad support geometry. Different unbalance eccentricities are considered. It is shown that bearing dynamic ...

Cha M.; Glavatskih S.

286

The vented pressure fed gas journal bearing  

International Nuclear Information System (INIS)

Hydrodynamic-type gas journal bearings with stabilising venting slots are often operated hydrostatically during starting-up as a means of 'jacking'. A simplified mathematical treatment of the circumferential gas flows in a vented, pressure-fed journal bearing is used to predict the relationship between load capacity, bearing geometry and gas properties. (author)

1962-01-01

287

Bears and pipeline construction in Alaska  

Energy Technology Data Exchange (ETDEWEB)

Serious problems were encountered with bears during construction of the 1274-km trans-Alaska oil pipeline between Prudhoe Bay and Valdez. This multi-billion-dollar project traversed both black bear (Ursus americanus Pallas) and grizzly bear (U. arctos L.) habitat throughtout its entire length. Plans for dealing with anticipated problems with bears were often inadequate. Most (71%) problems occurred north of the Yukon River in a previously roadless wilderness where inadequate refuse disposal and widespread animal feeding created dangerous situations. Of the 192 officially reported bear problems associated with the Trans-Alaska Pipeline System (TAPS) (1971-1979), about 65% involved the presence of bears in camps or dumps, 13% the feeding of bears on garbage or handouts, 10% property damage or economic loss, 7% bears under and in buildings, and only 5% charges by bears. Remarkably, no bear-related injuries were reported, suggesting that bears became accustomed to people and did not regard them as a threat. Following construction of the TAPS there have been proposals for pipelines to transport natural gas from Prudhoe Bay to southern and Pacific-rim markets. Based on past experience, some animal control measures were developed during the planning phase for the authorized gas pipeline route in Alaska. Fences installed around 100-person survey camps were found to be effective in deterring bears in two traditionally troublesome areas. 16 refs., 7 figs., 1 tab.

Follmann, E.H.; Hechtel, J.L. (Univ. of Alaska Fairbanks, AK (USA))

1990-06-01

288

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

DEFF Research Database (Denmark)

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

Thomsen, Kim; Klit, Peder

2012-01-01

289

Deformation history from microstructures: an example from Ramgarh Thrust Sheet, Eastern Himalaya  

Science.gov (United States)

The emplacement of thrust sheets in a fold and thrust belt is an integral part in the evolution of orogenic belts. The signatures of deformation present in a thrust sheet is often very useful to elucidate the history of deformation and also to understand the mechanisms of deformation that operates in stages during the emplacement of thrust sheets. The Himalayan orogenic belt has experienced multiple stages of thrusting and duplex formation. Ramgarh thrust sheet (RTS), one of the major thrust sheets bounded by the Main Central Thrust to the North and Ramgarh thrust (RT) in the south, is studied in the eastern Himalaya to understand its emplacement history and formation of microstructures in response to the deformation. The RTS consists dominantly of metapelitic sequence with intercalated quartzite bands. The present study attempts to understand the deformation history and mechanisms of deformation from microstructures developed in Daling group of rocks of the RTS, in the immediate northern side outside the Rangit window, Sikkim Himalaya. Three stages of cleavage formation in phyllite have been identified. The cleavages of the early stages are transposed to the present stage through the process of shearing adjacent to the RT fault zone as deformation progresses. The remnants of earlier cleavages are present as obliterated relict structures within the dominant last stage fabric. The evidence of shearing is present in both quartz-poor as well as in quartz-rich sericite schist. Schistosity plane is sheared to form S-C structure along with the development of pressure solution planes usually parallel to C-plane. Shear band cleavage is a common micro-scale structure in the deformed schistose rocks. Quartz grains in quartz mylonite have undergone crystal-plastic deformation and exhibit sweeping undulatory extinction, deformation bands, sub-grain formation and incipient to almost complete recrystallization of original grains. In phyllosilicate grains, undulatory extinction, bending of grains and local recrystallization are common. All these structures suggest that pressure solution, crystal-plastic dislocation creep, and recrystallization are the dominant deformation mechanisms operated in the process of deformation. The effects of crystal-plastic deformation and dynamic recrystallization near the RT fault are more pronounced while the pressure solution structure is predominantly developed further north in the sheet away from the RT fault. So, it is possible that the deformation of the rock within the RTS took place in varying deformation conditions, spatially arranged with respect to the RT fault. All the quasi-plastic deformation structures are overprinted by a later localized elastico-frictional deformation. The microstructural data suggest that the structures are formed in stages in a continuous tectonic regime related to the emplacement of RTS during the N-S shortening of the Himalayan orogen. Deformation partitioning is evident in large scale, spatially related with the RT fault as well as in micro-scale. The microstructure also suggests that relatively higher temperature and higher strain condition prevailed near the fault and are dissipated away from the RT fault.

Banerjee, S.; Matin, A.; Mukul, M.; Mukherjee, A.

2011-12-01

290

Polar Bears International: Wrangel Island, Russia  

Science.gov (United States)

This site describes the ongoing research of the polar bears in the Russian High Arctic. Wrangel Island with neighboring small island, Herald Island, are the key reproductive areas for the Chukchi-Alaskan polar bear population. Marine areas and Wrangel and Herald islands provide optimum foraging habitats for polar bears, and polar bear densities in these marine habitats are high all year round. Approximately 350-500 pregnant female polar bears construct their maternity dens on Wrangel and Herald islands every fall, emerging with their cubs in spring. The research is described in terms of goals and objectives, structure, methods, equipment, staff, and implementations.

291

Polar Bears International : Wrangel Island, Russia  

Science.gov (United States)

This site describes the ongoing research of the polar bears in the Russian High Arctic. Wrangel Island with neighboring small island, Herald Island, are the key reproductive areas for the Chukchi-Alaskan polar bear population. Marine areas and Wrangel and Herald islands provide optimum foraging habitats for polar bears, and polar bear densities in these marine habitats are high all year round. Approximately 350-500 pregnant female polar bears construct their maternity dens on Wrangel and Herald islands every fall, emerging with their cubs in spring. The research is described in terms of goals and objectives, structure, methods, equipment, staff, and implementations.

2007-12-12

292

Valve assembly having remotely replaceable bearings  

International Nuclear Information System (INIS)

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

1980-01-01

293

Low-friction coatings for air bearings in fuel cell air compressors  

Energy Technology Data Exchange (ETDEWEB)

In an effort to reduce fuel consumption and emissions, hybrid vehicles incorporating fuel cell systems are being developed by automotive manufacturers, their suppliers, federal agencies (specifically, the US Department of Energy) and national laboratories. The fuel cell system will require an air management subsystem that includes a compressor/expander. Certain components in the compressor will require innovative lubrication technology in order to reduce parasitic energy losses and improve their reliability and durability. One such component is the air bearing for air turbocompressors designed and fabricated by Meruit, Inc. Argonne National Laboratory recently developed a carbon-based coating with low friction and wear attributes; this near-frictionless-carbon (NFC) coating is a potential candidate for use in turbocompressor air bearings. The authors present here an evaluation of the Argonne coating for air compressor thrust bearings. With two parallel 440C stainless steel discs in unidirectional sliding contact, the NFC reduced the frictional force four times and the wear rate by more than two orders of magnitude. Wear mechanism on the uncoated surface involved oxidation and production of iron oxide debris. Wear occurred on the coated surfaces primarily by a polishing mechanism.

Ajayi, O. O.; Fenske, G. R.; Erdemir, A.; Woodford, J.; Sitts, J.; Elshot, K.; Griffey, K.

2000-01-06

294

Comparison of soft-tissue, dental, and skeletal characteristics in children with and without tongue thrusting habit.  

UK PubMed Central (United Kingdom)

BACKGROUND: Tongue thrusting habit is a condition in which the tongue makes contact with any teeth anterior to the molars during swallowing. Abnormal positioning of tongue may result in dental and skeletal abnormalities. OBJECTIVE: The aim of the present study was to study and compare soft-tissue, dental, and skeletal morphologic characteristics in children with and without tongue thrusting habit. MATERIALS AND METHODS: A total of 21 children with tongue thrusting habit and 21 children without any habit between age 10 and 14 years were selected for the study. Various soft-issue, dental and cephalometric parameters were measured and compared statistically. RESULTS: Significantly, higher number of children with tongue thrusting showed lip incompetency (86% vs. 14%), mouth-breathing habit (38% vs. none), hyperactive mentalis muscle activity (24% vs. none), Open-bite (52% vs. none) and lisping (86% vs. none) when compared to children without tongue thrust. Children with tongue thrust showed increased upper lip thickness and proclination of maxillary incisors No differences were found in angulation of mandibular incisors, inter-premolar or inter-molar widths and all the skeletal parameters studied. CONCLUSIONS: Tongue thrust seemed to affect some of the soft-tissue and dental characteristics causing lip incompetency, mouth-breathing habit, and hyperactive mentalis muscle activity, lisping, open-bite, and proclination of maxillary incisors; however, no significant skeletal changes were observed.

Dixit UB; Shetty RM

2013-01-01

295

Lubrication for high load duplex bearings  

Energy Technology Data Exchange (ETDEWEB)

Three ES and H-compatible lubricants (Environment, Safety and Health) for high load duplex bearing applications were evaluated and compared against trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon) which is an ozone-depleting solvent. Bearings with Supercritical CO{sub 2} deposition of PTFE extracted from Vydax AR/IPA, bearings with titanium carbide coated balls, and bearings with diamond-like carbon races and retainers were evaluated. Bearings with Supercritical CO{sub 2} deposition of PTFE from Vydax AR/IPA performed as well as bearings with Freon deposition of PTFE from Freon-based Vydax.

Steinhoff, R.G.

1997-08-01

296

Calculations of thrust generation by the driver system of a large blast simulator. Final report Feb-Dec 90  

Energy Technology Data Exchange (ETDEWEB)

A computational study was performed to determine the peak thrust which would be generated by cylindrical shock tube drivers of various lengths. Thrust histories were generated for two different flow conditions, one in which the shock tube was operated normally and the other in which a driver length adjusting device (hydroplug) failed. Once the magnitude and behavior of the thrust histories are understood, steps can be taken to design supports for the driver tubes which will withstand the cyclic loading associated with normal operation as well as the reverse loading associated with the component failure.

Schraml, S.J.

1991-03-01

297

What can the topography of thrust-related anticlines tell us about mechanical stratigraphy and pore fluid pressure?  

Science.gov (United States)

We demonstrate the effects of mechanical stratigraphy and pore fluid pressure on the fault structure and topography of thrust-related anticlines. We show that nucleation of secondary backthrusts is evidence of mechanically well-stratified, layered crust. Previously, Roering et al. [1997] found that interlayer slip above an active thrust fault results in positive Coulomb failure stress changes (?CFS), which favor secondary backthrust formation over updip propagation when the upper tip of the primary thrust is near an interface with low shear strength. Niño et al. [1998] subsequently showed that increasing displacement along a non-propagating basement-confined thrust results in backthrust strain within overlying layered rock. In this study, we use the Hoek-Brown (H-B) failure criterion to evaluate the tendency for backthrusting above propagating blind thrust faults. Half-space boundary element models loaded under increasing remote principal stress ratios are used to create predictive maps of H-B stability. The primary thrust is propagated and secondary faults are nucleated by adding fault segments in regions of predicted H-B failure from the previous loading step. Mechanical stratification is modeled as horizontal planes of low shear strength within a rock mass of higher uniform shear strength. We investigate patterns of thrust faulting within mechanically layered and mechanically homogeneous crust. Models of H-B failure around blind thrust faults in homogeneous crust show that these thrusts primarily propagate updip and that backthrusts are not predicted to form. This is consistent with predictions from ?CFS models. In layered crust, the tendency for backthrust nucleation is dependent on the strength of the rock layer that the primary thrust is propagating through. When the upper tip propagates through a weak layer or interface, backthrusts are not predicted to form by H-B failure because of the low shear strength, or correlatively high pore fluid pressure, of the material. Although the rock within the backthrust region experiences positive ?CFS, the absolute magnitudes of the H-B failure stresses are insufficient to nucleate faulting. When the upper tip propagates through a strong layer or interface, H-B and ?CFS models predict an equal tendency for backthrust nucleation and updip propagation of the primary thrust. The resulting anticline of layered crust is composed of the larger primary thrust-related fold with superimposed smaller anticlines above each backthrust. Backthrusts nucleating at shallower depths result in the smaller anticlines being increasingly closer to the axis of the primary fold. For folds in either homogeneous or layered crust, the flanks of the resulting anticlines are steepest on the side of the fold directly above the upper thrust tip. This provides a means of determining the dip direction of each thrust from topography. Mechanical stratification within a thrust-related anticline is reflected in backthrust-related topography. The presence of backthrusts, inferred from slope analysis of smaller anticlines superimposed on the larger primary thrust-related fold, indicates a layered mechanical stratification within the anticline. Where subsurface data are unavailable, such as on the moon or Mars, topographic observations of thrust-related anticlines can be used to infer mechanical stratigraphy. In terrestrial studies, the lack of backthrusts within anticlines of well-defined mechanical stratigraphy is evidence for high pore fluid pressure (low effective shear strength) during seismogenesis.

Okubo, C. H.; Schultz, R. A.

2002-12-01

298

Predicted Performance of a ThrustEnhanced SR-71 Aircraft with an External Payload  

UK PubMed Central (United Kingdom)

NASA Dryden Flight Research Center has completed a preliminaryperformance analysis of the SR-71 aircraft for use as a launchplatform for high-speed research vehicles and for carrying captiveexperimental packages to high altitude and Mach number conditions.Externally mounted research platforms can significantly increasedrag, limiting test time and, in extreme cases, prohibitingpenetration through the high-drag, transonic flight regime.To provide supplemental SR-71 acceleration, methods havebeen developed that could increase the thrust of the J58 turbojet engines.These methods include temperature and speed increases andaugmentor nitrous oxide injection. The thrust-enhanced engineswould allow the SR-71 aircraft to carry higher drag research platformsthan it could without enhancement.This paper presents predicted SR-71 performance with and withoutenhanced engines. A modified climb-dive technique is shownto reduce fuel consumption when flying through the transonicflight re...

Timothy R. Conners

299

Optimizing low-thrust and gravity assist maneuvers to design interplanetary trajectories  

CERN Multimedia

In this paper a direct method based on a transcription by finite elements in time has been used to design optimal interplanetary trajectories, exploiting a combination of gravity assist maneuvers and low-thrust propulsion. A multiphase parametric approach has been used to introduce swing-bys, treated as coast phases between two thrusted or coasting trajectory arcs. Gravity maneuvers are at first modeled with a linked-conic approximation and then introduced through a full three-dimensional propagation including perturbations by the Sun. The method is successfully applied to the design of a mission to planet Mercury, for which different options corresponding to different sequences of gravity maneuvers or launch opportunities are presented.

Vasile, Massimiliano

2011-01-01

300

Control of thrust vector of wheel propulsion system of the vessel  

Directory of Open Access Journals (Sweden)

Full Text Available A distinctive feature of a new passenger ship "Sura" is its propulsion system – two paddle wheels located at the stern of the ship, and the absence of a traditional steering wheel. Shiphandling is realized by means of independent electric drivers of paddle wheels. The navigator may implement a variety of maneuvers, changing the ratio of the rotating speed of paddle wheels. The navigator needs a device, showing the direction and value of the sum thrust vector, in order to effectively control the vessel. Expressions for the value of the thrust vector and its direction were obtained, and it allowed designing such a device. A structure of the control system and display of the propulsion system parameters and its implementation, mounted on the ship "Sura", and put into trial operation in navigation in 2011 are given in the paper.

Grosheva Lyudmila Serafimovna; Merzlyakov Vladimir Ivanovich; Perevezentsev Sergey Vladimirovich; Plyushchayev Valeriy Ivanovich

2011-01-01

 
 
 
 
301

Electromagnetic Analysis of Magnetic-Jack type CRDM for Thrust Force Improvement  

International Nuclear Information System (INIS)

[en] The magnetic-jack (magjack) type is used for control rod drive mechanism (CRDM) of the System-integrated Modular Advanced Reactor (SMART). An arrangement of three flat-face plunger electromagnets, when energized in a controlled sequence, will lift, hold, or insert a rod cluster in the reactor core. Especially the thrust force of magjack type electromagnet for the SMART needs more than that of KSNP (Korean Standard Nuclear Power Plant) under the same spatial constraints. In order to achieve improved thrust force, numerical magnetic field calculations for various kinds of magnetic yoke configuration of electromagnet have been performed. As a result, we present the improved design of electromagnet of magjack type CRDM for the SMART

2007-01-01

302

Electromagnetic Analysis of Magnetic-Jack type CRDM for Thrust Force Improvement  

Energy Technology Data Exchange (ETDEWEB)

The magnetic-jack (magjack) type is used for control rod drive mechanism (CRDM) of the System-integrated Modular Advanced Reactor (SMART). An arrangement of three flat-face plunger electromagnets, when energized in a controlled sequence, will lift, hold, or insert a rod cluster in the reactor core. Especially the thrust force of magjack type electromagnet for the SMART needs more than that of KSNP (Korean Standard Nuclear Power Plant) under the same spatial constraints. In order to achieve improved thrust force, numerical magnetic field calculations for various kinds of magnetic yoke configuration of electromagnet have been performed. As a result, we present the improved design of electromagnet of magjack type CRDM for the SMART.

Huh, Hyung; Lee, Jae Sun; Kim, Ji Ho; Choi, Suhn; Park, Keun Bae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2007-07-01

303

Drag/thrust analysis of jet-propelled transonic transport aircraft; definition of physical drag components  

Energy Technology Data Exchange (ETDEWEB)

Drag/thrust analysis of jet-propelled transonic transport aircraft on the basis of calculated viscous flow is discussed. Unique definitions for viscous drag plus wave drag and for induced drag are established. The concept of additive through flow drag is introduced. Drag/thrust bookkeeping is given attention. All drag components can be calculated in the flow region adjacent to the aircraft, where numerical accuracy is expectingly highest. Uniform handling of complex aircraft configurations is brought within reach. Near-field/far-field drag balances are exact. Computational aspects are discussed, in particular the elimination of spurious drag sources. Numerical examples are given for a wing-body and for a wing-body-pylon-nacelle configuration. In either case, the spurious drag sources are eliminated. Acceptable agreement is obtained for the total drag in the first case, and for the installation drag in the second case. Extension of the analysis presented to propeller-driven transport aircraft is straightforward. (author)

Destarac, D. [Office National d' Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France); Van der Vooren, J. [Senior research scientist, retired, Hoekse Waard (Netherlands)

2004-09-01

304

Switching control of thrust regulation and inlet buzz protection for ducted rocket  

Science.gov (United States)

The renewed interest on ducted rockets impulses their investigation. In this article, switching control in the working process of ducted rockets is focused on, in order to obtain optimal thrust control while avoiding phenomena like inlet buzz. Firstly multi-objective control problems of ducted rockets during its working process are discussed. Then the dynamic mathematical models of gas flow regulating system, thrust regulation control loop and inlet buzz protection loop are established and analyzed. Lastly, the switching strategy and PID controller are applied to the ducted rocket system, and the influence of integral limitation of controllers is analyzed. In conclusion, it is useful to introduce the multi-objective switching control to ducted rockets, and simulation results show its validity.

Bao, Wen; Li, Bin; Chang, Juntao; Niu, Wenyu; Yu, Daren

2010-10-01

305

Soil bentonite wall protects foundation from thrust faulting: analyses and experiment  

Science.gov (United States)

When seismic thrust faults emerge on the ground surface, they are particularly damaging to buildings, bridges and lifelines that lie on the rupture path. To protect a structure founded on a rigid raft, a thick diaphragm-type soil bentonite wall (SBW) is installed in front of and near the foundation, at sufficient depth to intercept the propagating fault rupture. Extensive numerical analyses, verified against reduced-scale (1 g) split box physical model tests, reveal that such a wall, thanks to its high deformability and low shear resistance, "absorbs" the compressive thrust of the fault and forces the rupture to deviate upwards along its length. As a consequence, the foundation is left essentially intact. The effectiveness of SBW is demonstrated to depend on the exact location of the emerging fault and the magnitude of the fault offset. When the latter is large, the unprotected foundation experiences intolerable rigid-body rotation even if the foundation structural distress is not substantial.

Fadaee, Meysam; Anastasopoulos, I.; Gazetas, G.; Jafari, M. K.; Kamalian, M.

2013-09-01

306

Relationship between net penetration rate and thrust of shielded TMB in hard rock  

Energy Technology Data Exchange (ETDEWEB)

Four tunnels have been planned to operate a large diameter shielded TMB in Gwangju urban subway construction site. No.1 tunnel has completely been excavated for 13 months operating. Net penetration rate and its relations with thrust force of the shielded TMB are analyzed in this report. This shallow depth tunnel of 536m length is located in soil layers at launching and in hard rocks at ending with 84m length. The weekly net penetration rates have dropped down as low as 20-110 mm/hr in rock while 400-800 mm/hr in soil. The actual penetration rates are proved to be high as the theoretical penetration rate which is analyzed in consideration of conditions of machine and rock. And net penetration rate is investigated to increase linearly with thrust force. (author). 8 refs., 2 tabs., 5 figs.

Park, Chul-Whan; Park, Chan; Jeon, Yang-Soo [Korea Institute of Geoscience and Mineral Resources, Taejeon(Korea); Park, Yeon-Jun [The University of Suwon, Whasung(Korea)

2002-06-30

307

A carbon bearing solid fuel  

Energy Technology Data Exchange (ETDEWEB)

The carbon bearing solid fuel (T), which produces no incomplete combustion products (CO, hydrocarbons (UV) and so on) contains a transfer metal (PM) or a mixture of metals and iron, cobalt, nickel, copper, zinc and manganese are most often used as the transfer metal. The red slag which is produced during purification of zinc or aluminum, which contains a number of transfer metals is specially used as a mixture of transfer metals. The production of fuel which produces no toxic gases is economical. The fuel is used for heating and cooking food.

Maeda, K.; Fudzii, D.; Khasidzume, B.

1983-02-15

308

Current leads and magnetic bearings  

Energy Technology Data Exchange (ETDEWEB)

Since the discovery of high-temperature superconductors (HTSs), Argonne National Laboratory (ANL) has been active in a broad spectrum of activities in developing these materials for applications. Work at every stage of development has involved industrial collaboration in order to accelerate commercialization. While most of the development work has been devoted to improving the properties of current-carrying wires, some effort has been devoted to applications that can utilize HTSs with properties available now or in the near future. In this paper, I discuss advances made at my laboratory in the area of current leads and magnetic bearings.

Hull, J.R.

1993-12-31

309

Regional structure and kinematic history of a large subduction back thrust: Taranaki Fault, New Zealand  

Science.gov (United States)

The Taranaki Fault is a back thrust antithetic to the Hikurangi margin subduction thrust. Subduction back thrusts, like the Taranaki Fault, accrue displacement transferred from the subducting plate, and growth analyses of these structures contribute to an improved understanding of subduction processes. The Taranaki Fault forms the eastern margin of the Taranaki Basin and is part of a system that extends for at least 600 km in continental crust of western New Zealand. The fault is preserved beneath young sedimentary cover and provides a rare opportunity to investigate the geometry and kinematic history of a large subduction back thrust. Two-dimensional seismic reflection lines (2-5 km spacing), tied to recently drilled wells and outcrop, together with magnetotelluric and gravity models are used to examine the fault. These data indicate that the fault is thick skinned with dips of 25-45° to depths of at least 12 km. The fault accommodated at least 12-15 km of dip-slip displacement since the middle Eocene (circa 40-43 Ma). The northern tip of the active section of the fault stepped southward at least three times between the middle Eocene and early Pliocene, producing a total tip retreat of 400-450 km. The history of displacements on the Taranaki Fault is consistent with initiation of Hikurangi margin subduction during the middle Eocene, up to 20 Ma earlier than some previous estimates. Fault tip retreat may have been generated by clockwise rotation of the subduction margin and associated progressive isolation of the fault from the driving downgoing Pacific Plate.

Stagpoole, V.; Nicol, A.

2008-01-01

310

Flapping tail membrane in bats produces potentially important thrust during horizontal takeoffs and very slow flight.  

UK PubMed Central (United Kingdom)

Historically, studies concerning bat flight have focused primarily on the wings. By analyzing high-speed video taken on 48 individuals of five species of vespertilionid bats, we show that the capacity to flap the tail-membrane (uropatagium) in order to generate thrust and lift during takeoffs and minimal-speed flight (<1 m (s-1)) was largely underestimated. Indeed, bats flapped the tail-membrane by extensive dorso-ventral fanning motions covering as much as 135 degrees of arc consistent with thrust generation by air displacement. The degree of dorsal extension of the tail-membrane, and thus the potential amount of thrust generated during platform launches, was significantly correlated with body mass (P?=?0.02). Adduction of the hind limbs during upstrokes collapsed the tail-membrane thereby reducing its surface area and minimizing negative lift forces. Abduction of the hind limbs during the downstroke fully expanded the tail-membrane as it was swept ventrally. The flapping kinematics of the tail-membrane is thus consistent with expectations for an airfoil. Timing offsets between the wings and tail-membrane during downstrokes was as much as 50%, suggesting that the tail-membrane was providing thrust and perhaps lift when the wings were retracting through the upstoke phase of the wing-beat cycle. The extent to which the tail-membrane was used during takeoffs differed significantly among four vespertilionid species (P?=?0.01) and aligned with predictions derived from bat ecomorphology. The extensive fanning motion of the tail membrane by vespertilionid bats has not been reported for other flying vertebrates.

Adams RA; Snode ER; Shaw JB

2012-01-01

311

Low-thrust hadron events with isolated ? or e from PETRA  

International Nuclear Information System (INIS)

This paper discusses a search for new quark flavors in which an excess of low-thrust events containing muons has been found for PETRA energies greater than 46.3 GeV. The muons in these events are quite isolated from hadronic energy, as would be expected from pair production of massive quarks. This paper presents the results of combining data from 4 PETRA experiments. Conclusions are then offered.

1987-01-01

312

A Layman's Guide to Thrust Engine Development for Super/Hyper Sonic Flight.  

Science.gov (United States)

The intention of this paper is to discuss the advances in thrust engines from the initial development of the J58/SR-71 (JT11D-20) of the U.S. Air Force's SR-71 Blackbird to the development of the RAM and SCRAM engines necessary to propel the new generations of high-flying super-speed aircraft. Engineering complexities suggest that the engines and…

Thiesse, James L.

313

Importance of head thrust test like bedside test in ENT outpatient clinic  

Directory of Open Access Journals (Sweden)

Full Text Available Head thrust test is a simple test that provides great information in the studyof patients with vestibular pathology. Despite a relatively low sensitivity, thespecificity is very high so it can be helpful in diagnosing severe vestibulardeficit as in the differential diagnosis of acute vestibular disorders such asneuritis vestibular. In this paper we review the physiology vestibulooculomotorreflex, performing the test, the interpretation of the results andthe advantages of its realization

Batuecas-Caletrio A, Muñoz Herrera A; Bronstein AM

2012-01-01

314

Exploraton within a complex thrust-fold system-Moruga East Field, Trinidad  

Energy Technology Data Exchange (ETDEWEB)

The Moruga East field is located in the south-eastern part of Trinidad within an area bounded by basement-related thrust faults. The application of recent models has led to the interpretation of the structural styles of the field for refining play concepts for exploration. A cross-sectional network for well-to-well correlations, migrated seismic, conventional aerial photographs and Trend Surface Analysis, were used for the structural and stratigraphic interpretation of the area. Structural elements are represented by asymmetrical thrust-folds, symmetrical anticlines, and a superimposed normal fault conjugate system which were generated by major phases of compressive deformation during the Miocene and Pliocene periods. Seismic evidence suggests that the intensity of compressional deformation shows diminished compression from the northwest to the southeast, where a deformation front is juxtaposed to a synclinal sedimentary basin that extends offshore. Structural analysis reveal a northeast-southwest trending antiform plunging to the southwest and tilted to the southeast at 17-20[degrees]. This structure is confirmed by Trend Surface Analysis using a 3rd order polynomial. Miocene asymmetrical thrust-folds and Pliocene thrust-splay faults within this structure represent the most attractive traps for exploitation. However, the superimposed normal fault conjugate system control the entrapment patterns of the field with the highest production realized in upthrown blocks bounding younger Pliocene reservoirs within the antiform. STratigraphic analysis using Top Lower Gros Morne as a Time Stratigraphic Datum suggests an onlap unconformity between the Pliocene Lower Gros Morne sands and the Upper Miocene Lower Cruse sands on a northwest-southeast high in the midsection of the field.

Wharton, S.R. (Trinidad and Tobago Petroleum Company Ltd., Santa Flora (Trinidad and Tobago))

1993-02-01

315

Demise of the Glide Mountain Thrust Pioneer Mtns, south central Idaho  

Energy Technology Data Exchange (ETDEWEB)

The Mississippian Copper Basin Formation (CBF) was interpreted by R.A. Paull and students to contain more than 5,000m of continuous section. T. Nilsen and J. Dover later inferred that the section was duplicated along a laterally extensive fault, the Glide Mountain Thrust (GMT). New geologic mapping and structural analysis of the GMT indicate it is not a regional thrust fault, but instead a lithologic contact or one of two types of faults. The GMT is reinterpreted as an abrupt or gradational depositional contact in many localities. In the south end of Muldoon Canyon, near the type locality of the CBF, abrupt contacts between cobble conglomerate and interbedded argillite and quartzite are depositional, not structural. In Phi Kappa Canyon and Little Copper Creek, thickness changes in the Drummond Mine Limestone member reflect depositional variations and not truncation by a thrust fault. Other evidence that previously supported the existence of the GMT included (1) a duplication of laterally equivalent submarine fan facies, and (2) contrasting deformational styles above and below the thrust. However, on-strike facies changes are so common that the correlation of stratigraphic units needs to be reevaluated, and the authors observed that deformational style is controlled mostly by location and lithology. The authors conclude that structural and stratigraphic evidence does not support the existence of the GMT and that the CBF comprises more than 5,000m of unduplicated section. Elimination of the GMT indicates that shortening within the CBF was accommodated mostly by folding. A minimum of 30% shortening occurred by east-vergent folding, while and additional, but unknown amount of shortening was accommodated by outcrop-scale folds and locally developed cleavage. The newly recognized normal faults are similar in style and geometry to Eocene normal faults in the upper plate of the Pioneer Mountains metamorphic core complex.

Wilson, E.; Rodgers, D.W. (Idaho State Univ., Pocatello, ID (United States). Dept. of Geology)

1993-04-01

316

Seismic isolation rubber bearings for nuclear facilities  

Energy Technology Data Exchange (ETDEWEB)

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

Fujita, Takafumi (Tokyo Univ., Inst. of Industrial Science (Japan))

1991-06-01

317

Seismic isolation rubber bearings for nuclear facilities  

International Nuclear Information System (INIS)

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

1989-01-01

318

[Lifting-thrusting and rotating manipulations: a comparison on energy input].  

UK PubMed Central (United Kingdom)

Through the energy input model of lifting-thrusting and rotating manipulations, using the theory of energy density, energy flux density and sound intensity level in physics, the average energy flux intensity and frequency distributions of average poynting's vector were calculated respectively within the range of infrasound. According to the distribution table, it was discovered that both of the energy flux density and sound intensity level during the process of acupuncture were high. And it was concluded that the essence of meridians was probably fascial tissues which were rich in elastic fibers and collagenous fibers. The heat-producing needling with reinforcing effect (setting the moutain on fire) which focused on forceful thrusting was held to be the result of the action of same position solitary wave. And the coolness-producing needling with reducing effect (thorough heavenly cool) emphasized on the manipulation of forceful lifting was considered as the action of opposite position solitary wave. The energy input of lifting-thrusting manipulation is comparatively larger than the rotating method, however without significant difference. The speed of manipulations applied is regarded to have greater impact on energy transmission. And the energy produced by rotating manipulation can be better transmitted through meridians.

Wang XM

2011-01-01

319

[Lifting-thrusting and rotating manipulations: a comparison on energy input].  

Science.gov (United States)

Through the energy input model of lifting-thrusting and rotating manipulations, using the theory of energy density, energy flux density and sound intensity level in physics, the average energy flux intensity and frequency distributions of average poynting's vector were calculated respectively within the range of infrasound. According to the distribution table, it was discovered that both of the energy flux density and sound intensity level during the process of acupuncture were high. And it was concluded that the essence of meridians was probably fascial tissues which were rich in elastic fibers and collagenous fibers. The heat-producing needling with reinforcing effect (setting the moutain on fire) which focused on forceful thrusting was held to be the result of the action of same position solitary wave. And the coolness-producing needling with reducing effect (thorough heavenly cool) emphasized on the manipulation of forceful lifting was considered as the action of opposite position solitary wave. The energy input of lifting-thrusting manipulation is comparatively larger than the rotating method, however without significant difference. The speed of manipulations applied is regarded to have greater impact on energy transmission. And the energy produced by rotating manipulation can be better transmitted through meridians. PMID:21355164

Wang, Xi-ming

2011-01-01

320

Localized Flow of Frictional Or Creeping Materials In A Lower Flat Thrust To Ramp Transition  

Science.gov (United States)

The passage of rock through zones of localized shear deformation in the form of back- thrusts or kink planes is common in fold and thrust belts. The stationary flow through these two types of hinges is examined for the particular case of a lower flat to ramp transition of a fault-bend fold. The simple shear transformation resulting in strain lo- calization is studied both analytically and numerically. The overall equilibrium of the hanging wall, accounting for friction over the ramp, constrains the shear and normal forces acting on the hinge boundaries. For frictional materials, the localization oc- curs in the form of a velocity discontinuity, defining the backthrust, with a dip which is shown not to bissect ramp angle nor to conserve the thrust nappe thickness, if a criteria based on a minimization of the total dissipation is considered. For creeping materials, the strain localization as a kink plane is shown to require a destabilizing deformation mechanism, selected here to be flexural slip. The rotation of the stress tensor due to the gradient in pressure, the thicknening and thinning of the creeping material, the rate and amount of flexural slip through the hinge are analyzed to define potential tectonic markers.

Maillot, B.; Leroy, Y.

 
 
 
 
321

Effect of outer wing separation on lift and thrust generation in a flapping wing system.  

UK PubMed Central (United Kingdom)

We explore the implementation of wing feather separation and lead-lagging motion to a flapping wing. A biomimetic flapping wing system with separated outer wings is designed and demonstrated. The artificial wing feather separation is implemented in the biomimetic wing by dividing the wing into inner and outer wings. The features of flapping, lead-lagging, and outer wing separation of the flapping wing system are captured by a high-speed camera for evaluation. The performance of the flapping wing system with separated outer wings is compared to that of a flapping wing system with closed outer wings in terms of forward force and downward force production. For a low flapping frequency ranging from 2.47 to 3.90 Hz, the proposed biomimetic flapping wing system shows a higher thrust and lift generation capability as demonstrated by a series of experiments. For 1.6 V application (lower frequency operation), the flapping wing system with separated wings could generate about 56% higher forward force and about 61% less downward force compared to that with closed wings, which is enough to demonstrate larger thrust and lift production capability of the separated outer wings. The experiments show that the outer parts of the separated wings are able to deform, resulting in a smaller amount of drag production during the upstroke, while still producing relatively greater lift and thrust during the downstroke.

Mahardika N; Viet NQ; Park HC

2011-09-01

322

Effect of outer wing separation on lift and thrust generation in a flapping wing system  

Energy Technology Data Exchange (ETDEWEB)

We explore the implementation of wing feather separation and lead-lagging motion to a flapping wing. A biomimetic flapping wing system with separated outer wings is designed and demonstrated. The artificial wing feather separation is implemented in the biomimetic wing by dividing the wing into inner and outer wings. The features of flapping, lead-lagging, and outer wing separation of the flapping wing system are captured by a high-speed camera for evaluation. The performance of the flapping wing system with separated outer wings is compared to that of a flapping wing system with closed outer wings in terms of forward force and downward force production. For a low flapping frequency ranging from 2.47 to 3.90 Hz, the proposed biomimetic flapping wing system shows a higher thrust and lift generation capability as demonstrated by a series of experiments. For 1.6 V application (lower frequency operation), the flapping wing system with separated wings could generate about 56% higher forward force and about 61% less downward force compared to that with closed wings, which is enough to demonstrate larger thrust and lift production capability of the separated outer wings. The experiments show that the outer parts of the separated wings are able to deform, resulting in a smaller amount of drag production during the upstroke, while still producing relatively greater lift and thrust during the downstroke.

Mahardika, Nanang; Viet, Nguyen Quoc; Park, Hoon Cheol, E-mail: hcpark@konkuk.ac.kr [Biomimetic and Intelligent Microsystems Laboratory, Department of Advanced Technology Fusion, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701 (Korea, Republic of)

2011-09-15

323

Mobile DNA and the TE-Thrust hypothesis: supporting evidence from the primates  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Transposable elements (TEs) are increasingly being recognized as powerful facilitators of evolution. We propose the TE-Thrust hypothesis to encompass TE-facilitated processes by which genomes self-engineer coding, regulatory, karyotypic or other genetic changes. Although TEs are occasionally harmful to some individuals, genomic dynamism caused by TEs can be very beneficial to lineages. This can result in differential survival and differential fecundity of lineages. Lineages with an abundant and suitable repertoire of TEs have enhanced evolutionary potential and, if all else is equal, tend to be fecund, resulting in species-rich adaptive radiations, and/or they tend to undergo major evolutionary transitions. Many other mechanisms of genomic change are also important in evolution, and whether the evolutionary potential of TE-Thrust is realized is heavily dependent on environmental and ecological factors. The large contribution of TEs to evolutionary innovation is particularly well documented in the primate lineage. In this paper, we review numerous cases of beneficial TE-caused modifications to the genomes of higher primates, which strongly support our TE-Thrust hypothesis.

Oliver Keith R; Greene Wayne K

2011-01-01

324

Mesozoic and Cenozoic structures of Pocatello region: transition from thrust belt to hinterland, southeast Idaho  

Energy Technology Data Exchange (ETDEWEB)

Remapping of upper Proterozoic and Cambrian rocks in the northern Bannock Range south and east of Pocatello, Idaho, indicates a polyphase deformation history characterized by both shortening and extension. Map-scale folds and faults, related to shortening in the transition zone between the Idaho-Wyoming thrust belt and the hinterland to the west, are present, but have been offset and rotated along superimposed normal faults. The oldest structure evident is the north-trending, east-vergent Rapid Creek fold. This fold involves upper Proterozoic and Cambrian strata in the hanging wall of the Putnam thrust fault. The fold is truncated by east-striking subvertical faults that are inferred to be coeval tear faults. Fold and fault geometries suggest the Rapid Creek fold formed over a footwall ramp, whose location may have been controlled by basement normal faults related to Proterozoic rifting. Further evidence of Mesozoic uplift lies in the sub-Neogene unconformity on Cambrian rocks in the Pocatello area, compared to areas of the thrust belt 15 km (9.3 mi) to the northeast, where similar tuffaceous strata rest on Triassic limestones, indicating 7 km (4.3 mi) of pre-Neogene erosion near Pocatello.

Burgel, W.D.; Rodgers, D.W.; Link, P.K.

1987-08-01

325

The Complete Two-Loop Integrated Jet Thrust Distribution In Soft-Collinear Effective Theory  

CERN Document Server

In this work, we complete the calculation of the soft part of the two-loop integrated jet thrust distribution in e+e- annihilation. This jet mass observable is based on the thrust cone jet algorithm, which involves a veto scale for out-of-jet radiation. The previously uncomputed part of our result depends in a complicated way on the jet cone size, r, and at intermediate stages of the calculation we actually encounter a new class of multiple polylogarithms. We employ an extension of the coproduct calculus to systematically exploit functional relations and represent our results concisely. In contrast to the individual contributions, the sum of all global terms can be expressed in terms of classical polylogarithms. Our explicit two-loop calculation enables us to clarify the small r picture discussed in earlier work. In particular, we show that the resummation of the logarithms of r that appear in the previously uncomputed part of the two-loop integrated jet thrust distribution is inextricably linked to the resum...

von Manteuffel, Andreas; Zhu, Hua Xing

2013-01-01

326

Stem thrust prediction model for W-K-M double wedge parallel expanding gate valves  

Energy Technology Data Exchange (ETDEWEB)

An analytical model for determining the required valve stem thrust during opening and closing strokes of W-K-M parallel expanding gate valves was developed as part of the EPRI Motor-Operated Valve Performance Prediction Methodology (EPRI MOV PPM) Program. The model was validated against measured stem thrust data obtained from in-situ testing of three W-K-M valves. Model predictions show favorable, bounding agreement with the measured data for valves with Stellite 6 hardfacing on the disks and seat rings for water flow in the preferred flow direction (gate downstream). The maximum required thrust to open and to close the valve (excluding wedging and unwedging forces) occurs at a slightly open position and not at the fully closed position. In the nonpreferred flow direction, the model shows that premature wedging can occur during {Delta}P closure strokes even when the coefficients of friction at different sliding surfaces are within the typical range. This paper summarizes the model description and comparison against test data.

Eldiwany, B.; Alvarez, P.D. [Kalsi Engineering Inc., Sugar Land, TX (United States); Wolfe, K. [Electric Power Research Institute, Palo Alto, CA (United States)

1996-12-01

327

Stem thrust prediction model for W-K-M double wedge parallel expanding gate valves  

International Nuclear Information System (INIS)

An analytical model for determining the required valve stem thrust during opening and closing strokes of W-K-M parallel expanding gate valves was developed as part of the EPRI Motor-Operated Valve Performance Prediction Methodology (EPRI MOV PPM) Program. The model was validated against measured stem thrust data obtained from in-situ testing of three W-K-M valves. Model predictions show favorable, bounding agreement with the measured data for valves with Stellite 6 hardfacing on the disks and seat rings for water flow in the preferred flow direction (gate downstream). The maximum required thrust to open and to close the valve (excluding wedging and unwedging forces) occurs at a slightly open position and not at the fully closed position. In the nonpreferred flow direction, the model shows that premature wedging can occur during ?P closure strokes even when the coefficients of friction at different sliding surfaces are within the typical range. This paper summarizes the model description and comparison against test data.

1996-01-01

328

Seismic evidence for blind thrusting of the northwestern flank of the Venezuelan Andes  

Science.gov (United States)

Surface geology and seismic and well data from the northwestern flank of the Venezuelan Andes indicate overthrusting of Andean basement rocks toward the adjacent Maracaibo Basin along a blind thrust fault. The frontal monocline is interpreted as the forelimb of a northwestward verging fault-related fold deformed over a crustal-scale ramp. The Andean block has been thrust 20 km to the northwest and uplifted 10 km on a ramp that dips about 20°-30° southeastward. The thrust fault ramps up through crystalline basement rocks to a decollement horizon within the shaly units of the Cretaceous Colon-Mito Juan formations. Backthrusts in the monocline produce a wedge geometry and reduce the amount of blind slip required on the decollement northwest of the Andes. The rigid Andean uplift was caused by northwest-southeast compressive tectonic forces related to the convergence of the Caribbean plate, the Panama volcanic arc, and northwestern South America. The thick (up to 6 km) molasse deposits accumulated in the foredeep basin indicate that the Venezuelan Andes started to rise as early as the early Miocene. However, a late Miocene intramolasse unconformity marks the beginning of the formation of the monocline and the greatest uplift. The crustal-scale fault-related fold model may explain structural features seen in other areas of basement-involved foreland deformation.

de Toni, Bruno; Kellogg, James

1993-12-01

329

A general thrust force model for delamination in drilling of composite laminates  

Energy Technology Data Exchange (ETDEWEB)

The drilling process is frequently applied to fiber-reinforced plastic composite laminates. Delamination has long been the major concern during the operation. Various tooling techniques dealing with this problem are recognized for their improvement. In analytical modeling, the fracture mechanics approach is used to describe the basic damage mechanism. This paper presents an extended analytical model to comprehend the effects of various drills based on the early plate delamination model. The axial thrust force remains the major factor causing the damage, while the distribution of this force determines the level of the largest endurable load, beyond which delamination occurs. The central concentrated load is a particular case of the general radially-distributed circular load, which represents the absolute minimum of the critical value. Tool design that distributes the thrust force radially can produce better cut quality in drilling by raising the limit of the endurable thrust force. The effects of fracture toughness, modulus of elasticity and ply thickness of the material and the controllability of the process by selecting the drilling parameters remain predictable as in the early model. In addition, the significance of the maximum flaw size in the material resulting from the laminate production and the direction of tool design are pointed out; hence, the important variables from the material, the drill and the cutting conditions can be integrated by this model. The experiment using four different drills verifies the approach.

Hocheng, H.; Chao, Y.C.; Puw, H.Y. [National Tsing Hua Univ., Hsinchu (Taiwan, Province of China)

1995-12-31

330

3D thrusting in frictional wedges : comparison between experimental observations and numerical predictions by limit analysis  

Science.gov (United States)

The objective is to capture 3D failure mechanisms, i.e., thrust surfaces in compressive accretionary wedges by the sole knowledge of the material and interface strengths. A 3D simple prototype composed by a flat sand layer topped with a wedge on one side and maintained between two lateral rigid walls is shortened by the relative movement of the two end walls. We consider laboratory data that demonstrate the important influence of the side wall friction on the position of thrust faults and on spurious departures from plane strain conditions, by comparing outcomes using the two possibles configurations of sand boxes (fixed or mobile base) (Souloumiac et al., J. Struc. Geol., 2012). The proposed method to reproduce these observations is the limit analysis. The 3D virtual velocity field is constructed by spatial discretisation. The numerical tool based on the limit analysis allows us to take into account the influence of the side wall friction and to find the 3D failure modes observed in the laboratory at the onset of thrusting. The comparison with the analogue experiments shows the connection between the virtual 3D velocity field and the actual deformation, and validates the numerical method. It is further applied to cases with lateral variations of surface slopes and basal friction to illustrate respectively the lateral transition from super to sub-critical conditions and the surface effect of patches of low friction on the décollement.

Souloumiac, Pauline; Krabbenhoft, Kristian; Maillot, Bertrand; Leroy, Yves M.

2013-04-01

331

Experimental Constraints On The Mechanical Strength Of Limestone On Shale Fault Zones: Implications For Natural Thrust Faults  

Science.gov (United States)

Carbonates and shales are common in fold and thrust belts worldwide: carbonates typically comprise the hanging wall of fault zones and the shale forms the footwall. Generally, a cataclasite is developed in both the carbonate and shale materials. Despite the wide occurrence of carbonate and shale cataclasites, little is known about the rheological behavior of these composites. We report on the results of velocity-stepping frictional sliding experiments conducted on calcite and shale composites. We examine the effect of gouge composition on the strength, fabric development and microstructural evolution of calcite and shale gouge zones. Room temperature, triaxial frictional sliding experiments were conducted on 2.54 mm diameter by 5 mm length cores containing a 1 mm thick, water saturated gouge layer along a 35° angle sawcut. Berea Sandstone, having a porosity of 17% comprises the upper forcing block while impermeable Badshot Dolomite comprises the lower forcing block. Experiments were conducted at 70 MPa confining pressure and displacement rates varied between 1 to 100 ?m s-1. Gouge material was created from quartz-bearing phyllosilicate-rich shale (31% quartz, 39% muscovite, 18% clinochlore, 11% feldspar) combined in various volumetric proportions with reagent grade calcite powder with an average grain size of ~5 ?m. Experiments were performed on each endmember composition as well as 75%, 50% and 25% mixtures of shale and calcite. Results show that all gouge compositions display velocity strengthening at the conditions tested. 100% calcite gouge is the strongest and displays initial rapid strain hardening followed by the evolution to ‘steady state’ on a load-displacement curve. Microstructural analysis shows moderately well developed R1 shears in the gouge that can extend into the sandstone and be filled with gouge material. The weakest material is the calcite/shale composites. At the highest shear strain, the 50% composites are the weakest material. Microstructures show well developed Y surfaces which we interpret to represent strain localization. The 100% shale is initially weaker than the composites but continues to strain harden, ultimately having more strength. Microstructures show more distributed flow of the material with little strain localization except along the interface between the forcing block and gouge. In all samples, gouge fills pore spaces in the sandstone forcing block creating a cuspate margin. In contrast, the gouge-dolomite margin is planar. Shearing typically localizes on the sandstone margin, suggesting that porosity of the forcing block plays a role in strain partitioning within the gouge. Initial observations on layered calcite/shale composites illustrate a striking difference to mixed composites. Strain is localized in the shale. The mechanical response shows very rapid initial strain hardening followed by a near ‘steady state’ deformation comparable to 100% shale. Experimental data will be compared to microstructures developed along natural limestone on shale thrust faults with the aim of placing constraints on the strength of natural systems.

Haywood, J.; Kennedy, L.

2009-12-01

332

Late Quaternary slip rates of two active thrust faults at the front of the Andean Precordillera, Mendoza, Argentina  

Science.gov (United States)

Several destructive earthquakes occurred in the last several hundred years along the active mountain front of the Andean Precordillera between 30°S and 33°S (Siame et al., 2002). However, slip rates of active reverse faults remain largely unknown and the seismic hazard related to these faults is still poorly constrained. Here we report slip rates for two active thrusts located north of Mendoza, the Penas and Cal thrusts, which offset Late Pleistocene to Holocene terraces and form well preserved fault scarps. At the Penas thrust three terraces (T1, T2 and T3) are displaced vertically by 0.9, 2 and 11 m, respectively. 10Be and 14C age constraints yield a vertical slip rate of ~0.9 mm/a for the Penas thrust fault. Combined with the dip angle of the fault of ~25°, this leads to a horizontal shortening rate of about 2 mm/a. At the Cal thrust the highest terrace, which has a maximum 10Be age of 12 ka, is displaced by ~7.5 m. This translates into a minimum horizontal shortening rate of about 1 mm/a. Comparison with short-term GPS data (Brooks et al., 2003) suggests that both the Penas and Cal thrusts accomodate a significant portion of the present-day E-W shortening rate in the eastern Andes. The vertical surface displacements derived from the smallest scarps is 0.9 m for both thrusts. Hence, given their length (Penas thrust: 40 km, Cal thrust: 31 km), these faults are capable of producing magnitude 7 earthquakes (Wells & Coppersmith, 1994), which is confirmed by a Ms = 7.0 earthquake on the Cal thrust that destroyed the city of Mendoza in 1861. Assuming characteristic earthquakes for both faults suggests average reccurence intervals of 1000 to 1500 years during the Holocene. References Brooks, B.A., Bevis, M., Smalley, R., Kendrick, E., Manceda, R., Lauria, E., Maturana, R., Araujo, M., 2003. Crustal motion in the Southern Andes (26°-36°S): Do the Andes behave like a microplate? Geochemistry Geophysics Geosystems 4, doi: 10.1029/2003GC000505. Siame, L.L., Bellier, O., Sébrier, M., Bourlès, D.L., Leturmy, P., Perez, M., Araujo, M., 2002. Seismic hazard reappraisal from combined structural geology, geomorphology and cosmic ray exposure dating analyses: the Eastern Precordillera thrust system (NW Argentina). Geophysical Journal International 150, 241-260. Wells, D.L., Coppersmith, K.J., 1994. New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement. Bulletin of the Seismological Society of America 84, 974-1002.

Hetzel, R.; Schmidt, S.; Ramos, V. A.; Mingorance, F.

2010-12-01

333

Analyze bearing problems by ball path inspection  

Energy Technology Data Exchange (ETDEWEB)

Failure analysis of a component, such as a rolling element bearing, requires collecting specific operating data nd a precise interpretation of the visual evidence of failure. Close examination of the contact surface of ball path, which the rolling elements inscribe on the inner and outer raceways of the bearing, can reveal conditions such as overloading, misalignment, or improper installation that shortens bearing life. Careful analysis of these ball paths greatly helps in pinpointing the cause of failure. The paper describes what causes a ball path, a normal ball path for rolling element bearings, a ball path due to rotor unbalance, ball paths due to axial overloading, distorted bearing housing effect on ball paths, and effect of radial bearing misalignment on ball path.

El Sherif, A.H. (Abu Dhabi Marine Operating Co. (United Arab Emirates))

1994-04-01

334

Feedback control for counterflow thrust vectoring with a turbine engine: Experiment design and robust control design and implementation  

Science.gov (United States)

Engineering research over the last few years has successfully demonstrated the potential of thrust vector control using counterflow at conditions up to Mach 2. Flow configurations that include the pitch vectoring of rectangular jets and multi-axis vector control in diamond and axisymmetric nozzle geometries have been studied. Although bistable (on-off) fluid-based control has been around for some time, the present counterflow thrust vector control is unique because proportional and continuous jet response can be achieved in the absence of moving parts, while avoiding jet attachment, which renders most fluidic approaches unacceptable for aircraft and missile control applications. However, before this study, research had been limited to open-loop studies of counterflow thrust vectoring. For practical implementation it was vital that the counterflow scheme be used in conjunction with feedback control. Hence, the focus of this research was to develop and experimentally demonstrate a feedback control design methodology for counterflow thrust vectoring. This research focused on 2-D (pitch) thrust vectoring and addresses four key modeling issues. The first issue is to determine the measured variable to be commanded since the thrust vector angle is not measurable in real time. The second related issue is to determine the static mapping from the thrust vector angle to this measured variable. The third issue is to determine the dynamic relationship between the measured variable and the thrust vector angle. The fourth issue is to develop dynamic models with uncertainty characterizations. The final and main goal was the design and implementation of robust controllers that yield closed-loop systems with fast response times, and avoid overshoot in order to aid in the avoidance of attachment. These controllers should be simple and easy to implement in real applications. Hence, PID design has been chosen. Robust control design is accomplished by using ?1 control theory in conjunction with the Popov-Tsypkin multiplier. The resulting optimization problem was solved using a real coded genetic-algorithm.

Dores, Delfim Zambujo Das

335

Improved analytical capabilities for foil air bearings. Phase 1. Final report, 15 September 1988-15 September 1989  

Energy Technology Data Exchange (ETDEWEB)

Completion of this Phase I study has presented an advanced analytic tool for predicting the performance of foil bearing and solid-walled bearing as well, operating at speeds wherein the Reynolds number is no longer small and the effects of the fluid inertia, the heat transfer and the turbulent flow become significant. The tool uses the 3-d Navier-Stokes approach for the fluid film thermohydrodynamics and the thermoelasticity treatment for the foil deformation. The Navier-Stokes approach is more complicated than the Reynolds equation approach, conventional or modified for the inclusion of inertia or turbulence. Nevertheless, the N-S approach has the capability of investigating the local behaviors of the lubricant and the foil. Especially, the prediction of temperature variation may eventually help explain the hot spots or burned spots which are often observed in a failed bearing. Two computer programs, 3DNSBRGJ (journal) and 3DNSBRGT (thrust) are developed through this Phase I study. The programs are capable of calculating bearing performance characteristics, and the velocity components, the temperature distribution, the foil deflection, the turbulence energy distribution and its dissipation rate.

Wu, E.R.; Wu, P.M.

1990-01-01

336

Hydrodynamic bearing for light loaded turbo machinery  

International Nuclear Information System (INIS)

The rotor of any turbo-machinery running in journal bearings is prone to two types of well-known vibrations. Synchronous Vibrations occur due to run out or forces resulting from unbalancing of the shaft. Sub synchronous vibrations are more serious, this phenomenon is commonly associated with oil film forces of the journal bearing. In order to avoid sub synchronous vibrations, different types of journal bearings having helical grooves were investigated both theoretically and experimentally. (author)

2003-01-01

337

Magnetostratigraphic constraints on the development of paired fold-thrust belts/foreland basins in the Argentine Andes  

Energy Technology Data Exchange (ETDEWEB)

Development of a paired fold thrust-thrust belt/foreland basin is correlated to the flattening of the subducting Nazca plate between 28-33{degree}S. Magnetostratigraphic studies in neogene basin-filling continental strata determine local basin subsidence rates and provide relatively precise chronostratigraphic correlation between different depositional environments. The data demonstrate that most existing lithostratigraphic units are diachronous and require new tectonic interpretations. Increases in sediment accumulation rates closely correspond to changes in provenance and indicate that the Frontal Cordillera, on the Chile-Argentina border was a positive topographic province by 18 Ma. The Precordillera evolved from {approx}16 Ma to the present as thrusting migrated from west to east. Published ages from intercalated airfall tuffs constrain some sedimentary sections in the eastern Sierras Pampeanas where the earliest uplift occurred since 10 Ma. The youngest uplifts are on the west side close to continuing thrusting in the Precordillera. Not all fold-thrust belt/foreland basin pairs are associated with flat subduction, suggesting that tectonic controls exceeding the scale of individual plate segments may be important. The hydrocarbon-producing Subandean fold-thrust belt/foreland basin, located in the area of 'steep' subduction that underlies northern Argentina and Bolivia (18-24{degree}S), is also believed to have evolved since middle Miocene time. Recently initiated magnetostratigraphic studies in the Subandean foreland basin will attempt to temporally constrain the Neogene tectonic evolution for comparison with the southern region.

Reynolds, J.H. (Norwich Univ., Northfield, VT (United States)); Damanti, J.F. (Miami Univ., OH (United States)); Jordan, T.E. (Cornell Univ., Ithaca, NY (United States))

1991-03-01

338

Comparison of electrostatic fins with piezoelectric impact hammer techniques to extend impulse calibration range of a torsional thrust stand.  

UK PubMed Central (United Kingdom)

With the progression of high-power electric propulsion and high thrust-to-power propulsions system, thrust stand diagnostics require high-fidelity calibration systems that are accurate over a large-range of thrust levels. Multi-mode and variable I(sp) propulsion devices also require that a single stand be capable of measuring thrust from 10's of uNs to 100's of mNs. While the torsional thrust stand mechanic and diagnostics are capable of operating over such a large range, current pulsed calibration schemes are typically limited to a few orders of magnitude of dynamic range. In order to develop a stand with enough dynamic range, two separate calibration methods have been examined and compared to create a combined system. Electrostatic fin (ESF) and piezoelectric impact hammer (PIH) calibration systems were simultaneously tested on a large scale torsional thrust stand system. The use of the these two methods allowed the stand to be calibrated over four orders of magnitude, from 0.01 mNs to 750 mNs. The ESF system produced linear results within 0.52% from 0.01 mNs to 20 mNs, while the PIH system extended this calibration range from 10 mNs to 750 mNs with an error of 0.99%. The two calibration methods agreed within 4.51% over their overlapping range of 10-20 mNs.

Pancotti AP; Gilpin M; Hilario MS

2012-03-01

339

Gearbox Reliability Collaborative Bearing Calibration  

Energy Technology Data Exchange (ETDEWEB)

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

van Dam, J.

2011-10-01

340

Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage.  

Science.gov (United States)

Recent studies have shown that the polar bear matriline (mitochondrial DNA) evolved from a brown bear lineage since the late Pleistocene, potentially indicating rapid speciation and adaption to arctic conditions. Here, we present a high-resolution data set from multiple independent loci across the nuclear genomes of a broad sample of polar, brown, and black bears. Bayesian coalescent analyses place polar bears outside the brown bear clade and date the divergence much earlier, in the middle Pleistocene, about 600 (338 to 934) thousand years ago. This provides more time for polar bear evolution and confirms previous suggestions that polar bears carry introgressed brown bear mitochondrial DNA due to past hybridization. Our results highlight that multilocus genomic analyses are crucial for an accurate understanding of evolutionary history. PMID:22517859

Hailer, Frank; Kutschera, Verena E; Hallström, Björn M; Klassert, Denise; Fain, Steven R; Leonard, Jennifer A; Arnason, Ulfur; Janke, Axel

2012-04-20

 
 
 
 
341

Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage.  

UK PubMed Central (United Kingdom)

Recent studies have shown that the polar bear matriline (mitochondrial DNA) evolved from a brown bear lineage since the late Pleistocene, potentially indicating rapid speciation and adaption to arctic conditions. Here, we present a high-resolution data set from multiple independent loci across the nuclear genomes of a broad sample of polar, brown, and black bears. Bayesian coalescent analyses place polar bears outside the brown bear clade and date the divergence much earlier, in the middle Pleistocene, about 600 (338 to 934) thousand years ago. This provides more time for polar bear evolution and confirms previous suggestions that polar bears carry introgressed brown bear mitochondrial DNA due to past hybridization. Our results highlight that multilocus genomic analyses are crucial for an accurate understanding of evolutionary history.

Hailer F; Kutschera VE; Hallström BM; Klassert D; Fain SR; Leonard JA; Arnason U; Janke A

2012-04-01

342

Journal bearing performance and metrology issues  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: In this paper, a radial clearance of a journal bearings and the metrology of the radial clearance measurement is described.Design/methodology/approach: In this experimental study out-of-roundness and radial clearance of journal bearings were measured with high precision and the impact of their metrology was examined on the specific oil film thickness of the bearing. Some metrological issues were emerged and these should be taken into account when bearings are designed.Findings: An investigation showed that the radial clearance measurements can vary from one measuring device to another and the specified clearance may not necessarily meet the design criteria of specific oil film thickness. The study indicates that the radial clearance measurement can differ from one measuring device to another depending upon the precision that can be achieved by the device. The radius of the bearing or the shaft also varies along the circumference, mainly due to out-of-roundness. The out-of-roundness contributes to the error in radial clearance measurement and hence similar to the cut off length specified with the surface roughness, the out-of-roundness needs to be specified with the radial clearance.Practical implications: The radial clearance of a journal bearing is a key design parameter and bearing performance mainly depends upon this parameter. In this paper was showed that the metrology of the radial clearance measurement plays a significant role and not only that the bearing manufacturer or the user of the bearing is aware of this fact but the bearing designer must also take this fact into account while designing bearingsOriginality/value: This paper showed that The radial clearance is a sensitive micro-geometry parameter and hence metrology plays a vital role in making decisions

S. Sharma; D. Hargreaves; W. Scott

2009-01-01

343

Imprints of Himalayan thrust tectonics on the Quaternary piedmont sediments of the Neora Jaldhaka Valley, Darjeeling Sikkim Sub-Himalayas, India  

Science.gov (United States)

Geological mapping in the Neora Jaldhaka Valley of the Darjeeling Sikkim Sub-Himalayan foothill region reveals the presence of discontinuous strands of tectonically active Quaternary thrust faults. The zones of active faulting coincide with occurrences of deeply incised piedmont deposits and river terraces along an E W trending corridor. In order of younging, the successive Quaternary thrust faults delineated are the Gorubathan, Matiali and Chalsa thrusts. Unequivocal geological evidence of surface-rupture faulting, however, is noted only along the Gorubathan thrust where the Precambrian Daling Group of rocks is thrust over the Quaternary piedmont sediments along a low northerly-dipping plane. The presence of deformational features in the Quaternary sediments such as anticlines, bending moment faults and back-tilting of both the piedmont and the incising river terraces along active fault scarps are interpreted to signify the presence of north-dipping blind thrusts below the Matiali and Chalsa scarps. Radiocarbon dates of organic-rich clay components indicate that the Gorubathan thrust post-dated 33,875 ± 550 Ybp and the lower bound age of the Chalsa thrust is 22,030 ± 130 Ybp. Successive foreland-ward development of these active strands and the increasing spacing between the successive thrust traces are interpreted to be due to foreland-propagating blind thrusts of the Himalayan FTB (Fold and Thrust Belt) in the Sub-Himalayan terrain. Evidences of backthrust movement are also presented along the Thaljhora North fault. The segmented and variable geometry of these thrusts imply that the MFT (Main Frontal Thrust) is still in its early stage of growth and the lateral linkages between the active fault-strands are yet to be established.

Guha, Dipayan; Bardhan, Sandeep; Basir, Shaikh Rezaul; de, Adhip Kanti; Sarkar, Amitabha

2007-05-01

344

Geometry and evolution of the frontal part of the Magallanes foreland thrust and fold belt (Vicuna Area), Tierra del Fuego, southern Chile  

Energy Technology Data Exchange (ETDEWEB)

The Magallanes foreland thrust and fold belt is a thin-skinned foreland thrust and fold belt of Paleocene to Oligocene age that deforms Upper Jurassic through Tertiary volcanic, volcaniclastic, and siliciclastic strata of the Magallanes basin, southern Andean Cordillera, Chile. This paper is a detailed description and analysis of the geology and structural evolution of the thrust front (Vicuna area of southern Tierra del Fuego). Reflection seismic and well data, together with 1:50,000 scale geological mapping, have been used in the analysis. In the southern part of the Vicuna area, two different thrust systems have been found: an upper imbricate fan that deforms Upper Jurassic and Cretaceous strata, and a younger, lower duplex composed of Cretaceous and probably Upper Jurassic rocks. The imbricate fan is characterized by fault-propagation folding in which listric thrust faults merge downward into a sole thrust that probably is located within the Upper Jurassic stratigraphy. The sole thrust of the upper imbricates forms the roof thrust of the underlying duplex. In the northern part of the Vicuna area, the syntectonic sedimentary wedge of the foredeep consists of Late Cretaceous through Tertiary siliciclastics that have been deformed and uplifted by passive back thrusting at the triangle zone. The structural style in the foreland region shows three main subhorizontal detachment levels located within the sedimentary wedge as a result of the progressive transfer of slip from the thrust belt to the foreland. Minor blind thrusts produce stacked [open quotes]pop up[close quotes] and triangle structures that result in complex geometries in the cores of anticlines. A forward-breaking sequence of thrusting is interpreted. During deformation, the active foredeep wedge migrated at least 10 km northward. Balanced geological cross sections indicate approximately 60% (-30 km) shortening for this part of the Magallanes thrust belt.

Alvarez-Marron, J.; McClay, K.R. (Univ. of London, Surrey (United Kingdom)); Harambour, S.; Rojas, L.; Skarmeta, J. (Empressa Nacional de Petroleo, Punta Arenas (Chile))

1993-11-01

345

Methods and systems for micro bearings  

Energy Technology Data Exchange (ETDEWEB)

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.

Stalford, Harold L.

2012-10-09

346

Genetic control of biennial bearing in apple  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Although flowering in mature fruit trees is recurrent, floral induction can be strongly inhibited by concurrent fruiting, leading to a pattern of irregular fruiting across consecutive years referred to as biennial bearing. The genetic determinants of biennial bearing in apple were investigated using...

Guitton, Baptiste; Kelner, Jean-Jacques; Velasco, Riccardo; Gardiner, Susan E.; Chagné, David; Costes, Evelyne

347

Can polar bear hairs absorb environmental energy?  

Directory of Open Access Journals (Sweden)

Full Text Available A polar bear (Ursus maritimus) has superior ability to survive in harsh Arctic regions, why does the animal have such an excellent thermal protection? The present paper finds that the unique labyrinth cavity structure of the polar bear hair plays an important role. The hair can not only prevent body temperature loss but can also absorb energy from the environment.

He Ji-Huan; Wang Qing-Li; Sun Jie

2011-01-01

348

Diffusion of Water with Gummy Bears  

Science.gov (United States)

In this activity, learners investigate the movement of water into and out of a polymer. Learners test the diffusion of water through gummy bears, which are made of sugar and gelatin (a polymer). Learners compare what happens when they put gummy bears are submerged in tap water versus distilled water.

Harris, Mary

2003-01-01

349

Positive contact, self retaining bearing seals  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a bearing. It comprises: an inner race; an outer race; bearing means engaged between the inner and outer races; means for sealing a space between the inner and outer races, a groove in one of the inner and outer races.

Johnson, B.H.; Larsen, L.

1992-05-05

350

Space-filling bearings in three dimensions  

CERN Document Server

We present the first space-filling bearing in three dimensions. It is shown that a packing which contains only loops with even number of spheres can be constructed in a self-similar way and that it can act as a three dimensional bearing in which spheres can rotate without slip and with negligible torsion friction.

Baram, R M; Rivier, N

2003-01-01

351

Cryopreservation of Brown Bear Skin Biopsies  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Genetic resource banks and assisted reproductive technologies support the conservation of endangered or threatened species. In this study we assessed two procedures to cryopreserve skin biopsies from live brown bears. Skin biopsies were taken from six live, anesthetized brown bears. Single biopsies ...

Caamaño, J.N. (J.); Rodríguez, A.; Muñóz, M.; De, C.; Díez, C.; Gómez, E.

352

Self-adjusting magnetic bearing systems  

Energy Technology Data Exchange (ETDEWEB)

A self-adjusting magnetic bearing automatically adjusts the parameters of an axially unstable magnetic bearing such that its force balance is maintained near the point of metastable equilibrium. Complete stabilization can be obtained with the application of weak restoring forces either from a mechanical bearing (running at near-zero load, thus with reduced wear) or from the action of residual eddy currents in a snubber bearing. In one embodiment, a torque is generated by the approach of a slotted pole to a conducting plate. The torque actuates an assembly which varies the position of a magnetic shunt to change the force exerted by the bearing. Another embodiment achieves axial stabilization by sensing vertical displacements in a suspended bearing element, and using this information in an electrical servo system. In a third embodiment, as a rotating eddy current exciter approaches a stationary bearing, it heats a thermostat which actuates an assembly to weaken the attractive force between the two bearing elements. An improved version of an electromechanical battery utilizing the designs of the various embodiments is described.

Post, Richard F. (Walnut Creek, CA)

1998-01-01

353

Overheated Journal Bearing Derailment Prevention System.  

Science.gov (United States)

The patent relates to an anti-derailment system to prevent train derailment due to axle failure resulting from journal bearing overheating. It includes a thermal sensor to continuously monitor the temperature of the bearing and to activate the brake syste...

J. H. Armstrong F. C. Kluge

1976-01-01

354

Shaft Center Orbit in Dynamically Loaded Bearings  

DEFF Research Database (Denmark)

The aim of this work is to demonstrate how to utilize the bearings damping coefficients to estimate the orbit for a dynamically loaded journal bearing. The classical method for this analysis was developed by Booker in 1965 and described further in 1972. Several authors have refined this method over the years. In 1966 Jorgen W. Lund published an approach to find the dynamic coefficients of a journal bearing by a first order perturbation of the Reynold's equation. These coefficients made it possible to perform a rotor-bearing stability analysis for a statically loaded bearing. In the mid seventies Jorgen W. Lund pointed out in lecture notes that the dynamic damping coefficients of the bearing could be used to find the shaft orbit for dynamically loaded bearings. For simplicity the "Short-Width-Journal-Bearing Theory" is used as a basis for finding the damping coefficients in this work, but the method is general and the damping coefficients could have been found also by numerical solutions.

Klit, Peder

355

Mechanics of Ramp Initiation and Ramp Spacing in Fold and Thrust Belts  

Science.gov (United States)

Numerous mechanical models have been proposed to explain both the systematic spacing of thrust ramps and the location of thrust ramp nucleation. The models predict that thrust ramps may be preceded by folding above the decollement. Conversely, ramps may initiate at either the base of the decollement and propagate upwards or well above the decollement zone and propagate upward toward the surface and downward, linking up with the decollement. We utilize a finite element model that incorporates a pressure-dependent, plastic rheology of up to 3 mechanical layers in a wedged-shaped geometry to investigate these issues. For a homogeneous model, plastic strain propagates in a broad band from the surface towards the base of the wedge prior to any significant folding. Once the band contacts the base, plastic strain localizes into a more narrow backthrust-thrust conjugate set. As the wedge is systematically displaced from the rear towards the foreland, plastic strain is preferentially localized in the foreland verging thrust. Subsequent ramps are developed in a similar manner. Ramp formation occurs sequentially at approximately the same horizontal distance along the base independent of variations in yield strength, dilation angle and basal friction values. The width of the wedge, as determined by the opening angle between the surface and basal slopes, is the primary factor in where a new ramp will nucleate. Secondarily, the amount shortening of the wedge must undergo prior to new ramp initiation is determined by both the mechanical properties within the wedge and the basal friction values. The two-layered heterogeneous models consist of a mechanically strong layer overlying a weak layer. In these models, plastic strain initiates as in the homogeneous models. However, with increased shortening of the wedge, plastic strain is largely localized within the stronger member. As the ramp propagates through the strong member, the layer is uplifted and the underlying weak layer is deformed to accommodate the displaced area beneath. The three-layered model consists of a mechanically weak basal layer, a middle layer that is mechanically stronger, and a top layer that is intermediate in strength. Ramp initiation is similar to the two-layered model, but more complex. Ramps always localize in the middle layer, but quickly propagate through all three layers. However, depending on the strength contrast between the middle and upper layer, plastic strain values may be highest in either layer. Comparison of these models to the Idaho-Wyoming-Utah fold and thrust belt shows the same systematically decrease of spacing and displacement of ramps towards the foreland. However, in comparison to some previous numerical models, our models show that, generally, faulting precedes folding in ramp initiation, spacing is dictated by wedge geometry, and once initiated, ramps localize within the stronger member of a layered wedge in front of the pre-existing ramp.

Panian, J.; Wiltschko, D. V.

2001-12-01

356

The Sandane Shear Zone: A Thrust Below the Nordfjord Ultrahigh-Pressure Province, Western Norway  

Science.gov (United States)

Many, if not most, continental ultrahigh-pressure (UHP) terranes are believed to exhume by detachment of a UHP sliver from a subducted continental margin, followed by buoyant extrusion of the sliver along the subduction interface. The key structural manifestations of this mechanism are thrust-sense displacements along the base of the exhumed sliver, and normal-sense motion along the contact above. This mechanism has been invoked for thin UHP bodies such as those in the western European Alps and the Kokchetav massif in Kazakhstan, where the upper and lower boundaries of the UHP units are exposed and kinematic information is preserved. For giant UHP terranes such as the Dabie Shan of China and the Western Gneiss Region of Norway, however, identification of a floor thrust beneath the eclogite-facies crust has remained elusive. The Nordfjord area of western Norway hosts the southernmost and largest province of UHP rocks in the Western Gneiss Region. A normal-sense shear zone—the Nordfjord-Sogn Detachment Zone (NSDZ)—has long been recognized overlying the Nordfjord high-pressure domain. The Sandane Shear Zone (SSZ) was included within the NSDZ by previous workers, but new mapping reveals indications of an earlier history: i) the SSZ follows the contact of allochthonous units that were thrust over the Western Gneiss Region basement; (ii) eclogite occurs within and above the SSZ, thus it underlies the Nordfjord high-pressure domain; (iii) most outcrop-scale deformation is the result of late extensional overprinting, but eclogites within the SSZ preserve early symmetric and asymmetric fabrics, whilst eclogites above the SSZ are predominantly weakly deformed or unfoliated. Fourteen single grains and multigrain fractions of zircon from a fine-grained eclogite (2.3 GPa, 600°C) within the lower part of the SSZ were dated by the TIMS method. The data define a discordia (MSWD=1.11) between an upper intercept of 1225±8 Ma, likely representing an igneous protolith age, and a lower intercept of 414±4 Ma. This preliminary result suggests the SSZ was active as a thrust, emplacing the allochthons over the WGR basement, at least as late as 414 Ma. Other U/Pb zircon studies of coarser-grained, higher temperature (~700°C) eclogite above the SSZ, however, yield dates as young as 405-400 Ma (Root et. al., 2004; Young et al., 2007). These data may imply top-foreland displacement on the SSZ had ceased before this time—if so, a structurally deeper thrust must be present if the Western Gneiss Region was extruded as a sliver, or alternatively, another mechanism was responsible for exhumation. A comprehensive, multi-technique study involving U/Pb, Lu/Hf and Sm/Nd methods is underway, focused upon ascertaining the youngest age of thrust displacement on the SSZ.

Young, D. J.; Root, D. B.; Hacker, B. R.

2009-12-01

357

Genomic sequencing of Pleistocene cave bears.  

UK PubMed Central (United Kingdom)

Despite the greater information content of genomic DNA, ancient DNA studies have largely been limited to the amplification of mitochondrial sequences. Here we describe metagenomic libraries constructed with unamplified DNA extracted from skeletal remains of two 40,000-year-old extinct cave bears. Analysis of approximately 1 megabase of sequence from each library showed that despite significant microbial contamination, 5.8 and 1.1% of clones contained cave bear inserts, yielding 26,861 base pairs of cave bear genome sequence. Comparison of cave bear and modern bear sequences revealed the evolutionary relationship of these lineages. The metagenomic approach used here establishes the feasibility of ancient DNA genome sequencing programs.

Noonan JP; Hofreiter M; Smith D; Priest JR; Rohland N; Rabeder G; Krause J; Detter JC; Pääbo S; Rubin EM

2005-07-01

358

Solid lubricants in rolling-contact bearings  

Energy Technology Data Exchange (ETDEWEB)

This article points out that in the application of solid lubricant coatings to the frictional surfaces in rolling-contact bearings, little use has been made of the technique of applying the coatings to the individual parts before assembly. Presents data from the literature on the life of solid lubricant coatings and self-lubricated separators in 204 bearings of the normal and high class of tolerances, respectively, these bearings having also been tested in a TsKB-72 tester. Notes that the rolling-contact bearings packed after assembly with the solid lubricant gave longer lives than the bearings with the solid lubricant coating or with the self-lubricated separator, even though the test conditions were more severe.

Glodin, Yu.N.; Eliseenko, A.G.

1982-09-01

359

Marine bearing for a downhole drilling apparatus  

Energy Technology Data Exchange (ETDEWEB)

A bearing supports a rotatable shaft in a fluid environment. The bearing can be utilized to support a drive shaft connected to a drill bit in a downhole drilling apparatus. The drive shaft extends through a housing in which drilling fluid is flowing. Preferably, the bearing includes an inner elastomeric sleeve and an outer rigid sleeve attached to the interior side wall of the housing. The drive shaft has a wear sleeve attached for rotation therewith. The wear sleeve is rotatably received in the bearing inner sleeve. The inner sleeve is relatively short as compared with the drive shaft and absorbs radial loads imposed on the drive shaft. The bearing is lubricated by a portion of the drilling fluid in the housing which flows between the exterior side wall of the wear sleeve and the interior side wall of the inner sleeve.

Beimgraben, H.W.

1984-07-31

360

Wave journal bearing. Part 2: Experimental pressure measurements and fractional frequency whirl threshold for wave and plain journal bearings  

Energy Technology Data Exchange (ETDEWEB)

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 ed 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 bearing 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.

Walker, J.F.; Addy, H.E. Jr. [NASA Lewis Research Center, Cleveland, OH (United States); Dimofte, F. [Univ. of Toledo, OH (United States)

1995-12-31

 
 
 
 
361

Structural styles of the Guess Creek fault block beneath the Great Smoky thrust sheet, Blount County, Tennessee  

Energy Technology Data Exchange (ETDEWEB)

A road cut along US 321 N, approximately 1 km NW of Walland, TN, exposes a previously unexposed complexly deformed section of Middle Ordovician clastic wedge [Chickamauga Group, Sevier Shale] sedimentary rocks. It provides an excellent opportunity to analyze both the lithologic assemblages and complex folding and faulting beneath the Great Smoky thrust sheet. Arkosic quartzite of the Lower Cambrian Cochran Conglomerate [Chilhowee Group], has been thrust over weaker Sevier Shale in the hanging wall of the Guess Creek fault. Regionally, the Great Smoky fault separates metamorphosed Precambrian to Lower Cambrian clastic shelf, slope, and rift facies rocks of the western Blue Ridge from Cambro-Ordovician carbonate shelf and orogenic wedge deposits of the foreland fold and thrust belt. West of the Great Smoky fault, the Guess Creek fault has been interpreted to floor duplexed Cambro-Ordovician rocks exposed in windows beneath the Great Smoky thrust sheet in the vicinity of the Great Smoky Mountains National Park. The Sevier Shale here consists of variably cleaved shale, siltstone, sandstone, and conglomerate. It exhibits a variety of fold styles throughout the exposure, ranging from predominantly noncylindrical tight folds to broad, open structures. A weak axial-planar pencil cleavage is developed in the Middle Ordovician shale and siltstone, along with a secondary cleavage that transects the axial surfaces of the folds. Minor thrust faults within the Sevier Shale appear to have formed by propagation through tightened fold hinges or bedding-parallel slip. The fold pattern observed in the roadcut appears to be partly the result of movement along a tear fault that broke both the hanging wall and footwall of the Great Smoky thrust sheet after emplacement. Slickenline orientations along minor thrust surfaces in the Cochran Conglomerate indicate eastward-directed, oblique-slip movement of the tear fault.

Carter, M.W.; Davidson, G.L.; Heller, J.A. (Univ. of Tennessee, Knoxville, TN (United States). Dept. of Geological Sciences); Hatcher, R.D. Jr. (Oak Ridge National Lab., TN (United States))

1993-03-01

362

Map-scale dextral folds in the footwall of a far traveled crystalline thrust sheet, Alabama-Georgia Appalachians  

Energy Technology Data Exchange (ETDEWEB)

A series of dextral, map-scale folds occurs in the immediate footwall of both the roof and floor thrusts of the Hollins Line thrust duplex, the boundary between the eastern and western Blue Ridge in Alabama and west Georgia. Spaced between 20 and 60 km along a 150 km fault trace, these folds, which are decapitated by the overlying thrust, consist of anticline-syncline pairs within lower greenschist facies rocks of the structurally uppermost Talladega belt. Synclines occur to the SW of anticlines, generally are cored by Hillabee Greenstone Hillabee Greenstone, and are more open than the paired anticlines which are cored by quartzites of the Butting Ram and Cheah Quartzites and Jemison Chert, and die out structurally downward into the Lay Dam Formation. Short limbs are steep to overturned t the west or northwest and are highly oblique ([approx]90[degree]) to the thrust trace, whereas long limbs are upright and subparallel to the thrust trace. Half wavelengths are 1.5--2 km, and amplitudes are approximately 1 km. Four such fold pairs have been studied: near Wogufka, Chandler Springs, and Pyriton, Alabama and Tallapoosa, Georgia. Folds range from upright shallowly plunging to reclined, and plunge beneath the overlying thrust fault. Two of the fold pairs (Pyriton and Tallapoosa) occur at localities where the fault trace undergoes significant strike changes ([approx]40[degree]) from EW to NE, and these bends correspond to similar changes in strike of footwall stratigraphy. The previously metamorphosed and deformed Talladega belt footwall experienced map-scale dextral shear as the far traveled high-grade eastern Blue Ridge allochthon was emplaced upon it during the Alleghanian. The sole of the terrane boundary thrust is regionally within the Hillabee Greenstone, but heterogeneities caused by the large-scale folds resulted in decapitation of the folds during final nappe emplacement.

Tull, J.F. (Florida State Univ., Tallahassee, FL (United States). Dept. of Geology)

1994-03-01

363

Structural styles of subandean fold and thrust belt of Peru and Southern Ecuador  

Energy Technology Data Exchange (ETDEWEB)

Along-strike variations in structural styles of the east-verging Subandean fold and thrust belt (SAFTB) in Peru and southern Ecuador are controlled by the presence or absence of thick Late Permian to Jurassic evaporite sequences rather than changes in subducting plate geometries as has been suggested previously for the Andes. Salt distribution and thickness have not only controlled the styles and segmentation along the SAFTB but also have been important factors in strike variations across the belt. The southern Ecuador SAFTB lacks significant evaporite units and is characterized by thick-skinned deformation that encompasses high-angle reverse faults, and broad, low-amplitude folds. The style changes to thin-skinned deformation near 2S lat. and it is well illustrated in the Santiago and Huallaga basins where thick evaporite units are present. This segment is characterized by a major decollement on the salt, grabens formed by salt withdrawal from reactivation of thrust faults as listric normal faults, salt piercement at or near synclinal axes, and periclines and asymmetric folds. The frontal thrust of this thin-skinned segment consists of box, overturned and upright folds above shallow salt domes, and by a major backthrust at the mountain front. This segment extends to 1030'S lat., near Oxapampa, Peru, where the thin-skinned SAFTB is narrow and changes across strike to a thick-skinned deformation as the evaporite units thin and disappear eastward. South of 1030'S lat., a new thick-skinned deformation segment is present in southern Peru and characterizes most of the deformation in the SAFTB of the Ucayali and Madre De Dios basins.

Aleman, A.M.

1988-01-01

364

Flow Visualizations and Extended Thrust Time Histories of Rotor Vortex Wakes in Descent  

Science.gov (United States)

An experimental study is performed on a three-bladed rotor model in a water tow tank. The blade pitch and rotational velocity, the rotor plane angle of attack (descent angle), and the carriage speed are all varied in order to simulate a wide range of rotorcraft operating states, with the focus being on descent speeds and angles where the rotor is operating in or near vortex ring state an area in which there is currently very little available data. Circulation and blade Reynolds numbers are of order 10^5. Flow visualization is done by injecting air bubbles and fluorescent dye tangentially from the blade tips to mark the vortex core, showing the development of both short-wave (sinuous) and long-wave (leapfrogging) instabilities on the helical vortices in the wake. Strain gages are used to record transient loads, allowing a correlation between the rotor thrust performance and the development of the vortex wake. Test runs are performed for extended periods up to 500 rotor revolutions demonstrating the repeatability of the patterns of thrust variation. The data indicate that as the instabilities develop, adjacent vortices merge and form thick vortex rings, especially during descent. Periodic shedding of these rings from the wake associated with vortex ring state is observed, resulting in peak-to-peak thrust fluctuations of up to 95% of the mean and occurring at regular intervals of 2050 rotor revolutions, depending on flow parameters. Preliminary particle image velocimetry (PIV) data provide a quantitative measure of the entire rotor flow field for the case of a hovering rotor. The data yield additional information on the vortex filament instability, in particular the axial flow in the vortex cores.

Stack, James; Caradonna, Frank; Savas, Omer

2003-11-01

365

Numerical investigation of the thrust efficiency of a laser propelled vehicle  

Energy Technology Data Exchange (ETDEWEB)

This thesis is about the gasdynamics of laser propulsion, and studies the expansion efficiency of the blast wave generated when the propellant is superheated by laser. The flow situation for a thruster propelled by ablated gas which is energized by a laser pulse is numerically simulated. The flow is axisymmetric and nonsteady, and is assumed to be inviscid due to its high Reynolds number. The high pressure expansion of the laser heated gas generates thrust as it pushes against the vehicle. Gas expansion lateral to the thrust vector causes performance to decrease. The vehicle geometry and the laser pulse characteristics determine the degree to which the flow is one dimensional. As the thruster's parameters are varied, its impulse is calculated and compared to the limiting impulse of a one-dimensional system, and thus the thrust efficiency is computed. Lateral expansion losses computed by simulating the flow of the expanding gas time-accurately on a computer are far less than losses predicted using the method of characteristics, which is the best alternate means of computation. Flows which exhibit a substantial amount of lateral expansion can still yield an expression efficiency which exceeds 70%. Steger and Warming's flux split numerics for the Euler equations are modified for blast simulations into near vacuum ambient conditions. The majority of the calculations performed assume an ideal gas equation of state with {gamma} = 1.2. The propellant Lithium Hydride has shown excellent promise in the laboratory, yielding I{sub sp} = 800 --1000 sec. Equilibrium and kinetic modeling of LiH is undertaken. These additional mechanisms are then incorporated into the efficiency calculations. 32 refs., 54 figs., 16 tabs.

Mulroy, J.R. (Stanford Univ., CA (United States))

1990-08-01

366

Duplex development and abandonment during evolution of the Lewis thrust system, southern Glacier National Park, Montana  

Energy Technology Data Exchange (ETDEWEB)

The westernmost duplex (Brave Dog Mountain) includes the low-angle Brave Dog roof fault and Elk Mountain imbricate system, and the easternmost (Rising Wolf Mountain) duplex includes the low-angle Rockwell roof fault and Mt. Henry imbricate system. The geometry of these duplexes suggests that they differ from previously described geometric-kinematic models for duplex development. Their low-angle roof faults were preexisting structures that were locally utilized as roof faults during the formation of the imbricate systems. Crosscutting of the Brave Dog fault by the Mt. Henry imbricate system indicates that the two duplexes formed at different times. The younger Rockwell-Mt. Henry duplex developed 20 km east of the older Brave Dog-Elk Mountain duplex; the roof fault of the former is at a higher structural level. Field relations confirm that the low-angle Rockwell fault existed across the southern Glacier Park area prior to localized formation of the Mt. Henry imbricate thrusts beneath it. These thrusts kinematically link the Rockwell and Lewis faults and may be analogous to P shears that form between two synchronously active faults bounding a simple shear system. The abandonment of one duplex and its replacement by another with a new and higher roof fault may have been caused by (1) warping of the older and lower Brave Dog roof fault during the formation of the imbricate system (Elk Mountain) beneath it, (2) an upward shifting of the highest level of a simple shear system in the Lewis plate to a new decollement level in subhorizontal belt strata (= the Rockwell fault) that lay above inclined strata within the first duplex, and (3) a reinitiation of P-shear development (= Mt. Henry imbricate faults) between the Lewis thrust and the subparallel, synkinematic Rockwell fault.

Yin, An; Kelty, T.K.; Davis, G.A. (Univ. of Southern California, Los Angeles (USA))

1989-09-01

367

Surface flow studies of restricted shock separation in a thrust optimized parabolic nozzle  

Science.gov (United States)

In this paper, surface flow features such as length of separation region and separation bubble are studied during restricted shock separation condition in a thrust optimized parabolic nozzle. It is found that peaks in the variation of these surface flow features are directly related to beginning of conditions for flow transition suggesting changes in exhaust flow features which are responsible for initiating flow transitions in a nozzle. Results are obtained from surface oil tests performed during the shut down phase for a range of nozzle pressure ratio during which restricted shock separation condition is prevalent.

Verma, Shashi B.; Haidn, O.

2009-10-01

368

Quasioptimal control with feedback for multiorbit low-thrust transfer between noncoplanar elliptic and circular orbits  

Science.gov (United States)

The problem of synthesizing stable feedback control is considered based on solving the problem of time minimization for a multiorbit transfer between noncoplanar elliptic and circular orbits in a Newtonian gravitational field. The problem is solved using asymptotic properties and symmetries of optimal control in the unperturbed problem. Stability of the obtained control against external perturbations, deviations of initial conditions, and errors in thrust vector realizations is demonstrated. The obtained quasioptimal control with feedback can be used as an onboard algorithm of spacecraft control and when performing design and ballistic analysis.

Petukhov, V. G.

2011-04-01

369

Numerical investigation of the thrust efficiency of a laser propelled vehicle  

Energy Technology Data Exchange (ETDEWEB)

The flow situation for a thruster propelled by ablated gas which is energized by a laser pulse is numerically simulated. The flow is axisymmetric and nonsteady, and is assumed to be inviscid due to its high Reynolds number. The high pressure expansion of the laser heated gas generates thrust as it pushes against the vehicle. Gas expansion lateral to the thrust vector causes performance to decrease. The vehicle geometry and the laser pulse characteristics determine the degree to which the flow is one dimensional. As the thruster's parameters are varied, its impulse is calculated and compared to the limiting impulse of a one-dimensional system, and thus the thrust efficiency is computed. Lateral expansion losses computed by simulating the flow of the expanding gas time-accurately on a computer are far less than losses predicted using the method of characteristics, which is the best alternate means of computation. Flows which exhibit a substantial amount of lateral expansion can still yield an expansion efficiency which exceeds 70%. This finding has significant implications on the eventual design of flight hardware. Steger and Warming's flux split numerics for the Euler equations are modified for blast simulations into near vacuum ambient conditions. At the interface between the near vacuum ambient and the wave front, the solution is first order accurate but sufficiently robust to handle pressure ratios exceeding one million and density ratios exceeding 10,000 between the thrust gas and the ambient gas. Elsewhere the solution is second order accurate. The majority of the calculations performed assume an ideal gas equation of state with {gamma} = 1.2. The propellant Lithium Hydride has shown excellent promise in the laboratory, yielding I{sub sp} = 800-1000 sec. Equilibrium and kinetic modeling of LiH is undertaken, with a variable {gamma} of from 1.25 to 1.66 resulting from the kinetic assumptions of ionization equilibrium and frozen chemistry. These additional mechanisms are then incorporated into the efficiency calculations.

mulroy jr

1990-08-01

370

Effect of fluid overpressure on thrust wedges deformation - insight from sandbox models  

Science.gov (United States)

Elevated pore pressures are commonly invoked as a key factor for thrust wedges deformation. Even in the well-known and widely used critical taper model of an accretionary wedge, they are introduced as a first-order parameter. This parameter is the Hubbert-Rubey pore pressure ratio ?. Despite the fact that the importance of fluid overpressure is not discussed and that more and more field measurements focus on quantifying pressure distributions, either numerical or analogue modelers are a few to take into account fluid pressure in their modeling. In the critical taper model, fluid overpressure reduces frictional resistance at the base and many experimenters used low frictional materials to create basal detachments. But fluid overpressures also act as body forces on the whole wedge in addition to that of gravity and this second effect was never experimentally confirmed. In this work, we performed scaled experiments in which compressed air is used as the pore fluid, to understand how fluid pressure controls the first stages of thrusting. The models were built with non-cohesive sand in their upper part and glass microbeads for the décollement to insure the weakness of the detachment. Both materials have similar permeabilities and as we applied horizontally varying fluid pressureat the base of the model, the pore pressure ratio ? was almost constant in the whole wedge. We found a good match with the critical taper model predictions. Combining these experiments with an optical image correlation technique (particle imaging velocimetry - PIV), we were able to follow the strain in the model during the entire duration of the shortening. In particular, we studied the propagation of the décollement and highlighted a strong influence of the pressure ratio, ?, on the activation rate of the décollement. Indeed, higher the overpressure is, faster the propagation of the décollement is. Moreover, we found that the distance to the critical taper condition, which depends on both values of topographic angle, ? and pressure ratio, ? plays a major role in the strain localization. For example, in case of wedges deforming by thrusting, closer to the critical taper conditions the wedge is, more diffuse the thrusts are.

Pons, A.; Mourgues, R.

2012-04-01

371

Dynamic response of a rub-impact rotor system under axial thrust  

Energy Technology Data Exchange (ETDEWEB)

A model of a rigid rotor system under axial thrust with rotor-to-stator is developed based on the classic impact theory and is analyzed by the Lagrangian dynamics. The rubbing condition is modeled using the elastic impact-contact idealization, which consists of normal and tangential forces at the rotor-to-stator contact point. Mass eccentricity and rotating speed are used as control parameters to simulate the response of rotor system. The motions of periodic, quasi-periodic and chaotic are found in the rotor system response. Mass eccentricity plays an important role in creating chaotic phenomena. (orig.)

An, Xueli; Zhou, Jianzhong; Xiang, Xiuqiao; Li, Chaoshun; Luo, Zhimeng [Huazhong University of Science andTechnology, College of Hydroelectric and Digitalization Engineering, Wuhan, Hubei (China)

2009-11-15

372

Deformation style in the Munsiari Thrust Zone: a study in the Madlakia-Munsiari-Dhapa section in north-eastern Kumaun Himalaya  

Science.gov (United States)

The Main Central Thrust demarcates the boundary between the Lesser Himalaya and the Higher Himalaya in the Himalayan orogen. Several definitions of the Main Central Thrust have been proposed since it was originally described as the southern boundary of the crystalline rocks (the Main Central Thrust mass) in the Kumaun-Garhwal Himalaya. The long-held contention that the Munsiari Thrust represents the Main Central Thrust has been negated by recent isotopic studies. One way to define the Main Central Thrust is that it is a ductile shear zone that is delimited by the Munsiari Thrust (MCT-I) in south and the Vaikrita Thrust (MCT-II) in north. The alternative proposition that the Vaikrita Thrust represents the Main Central Thrust is fraught with practical limitations in many parts of the Himalaya, including the study area. In the metamorphic rocks bounded between the Vaikrita Thrust and the Munsiari Thrust, the isoclinal folds of the earliest phase are routinely ascribed to the pre-Himalayan orogeny, whereas all subsequent folding phases are attributed to the Himalayan orogeny. This article elucidates the structural characteristics of the kilometre-thick Munsiari Thrust Zone and revisits the issue of pre-Himalayan orogenic signatures in the thrust zone. With the help of high-resolution field mapping and the analyses of mesoscopic scale structures, we demonstrate that the Munsiari Thrust is a typical fault zone that is made up of a fault core and two damage zones. The fault core traces the boundary between the quartzite and the biotite-gneiss. The damage zones consist of the low-grade metasedimentary rocks in the footwall and the gneiss-migmatite in the hanging wall. The entire fault zone shares an essentially common history of progressive ductile shearing. Successively developed mesoscopic folds trace various stages of progressive ductile shearing in the damage zones. Two recognizable stages of the shearing are represented by the early isoclinal folds and the late kink folds. As the strain during progressive deformation achieved the levels that were too high for accommodation by ductile flow, it was released by development of a tectonic dislocation along a mechanically weak boundary, the Munsiari Thrust. The isoclinal folds and the Munsiari Thrust were developed at different stages of a common progressive deformation during the Himalayan orogeny. Contrary to the popular notion of consistency with respect to orientation, the stretching lineations show large directional variability due to distortion during the late folding.

Moharana, Abhishek; Mishra, Anurag; Srivastava, Deepak C.

2013-04-01

373

Movable bearing case clearing machine  

UK PubMed Central (United Kingdom)

The utility model relates to a movable load bearing knock-out machine which comprises a long cylinder-shaped pump body and a waterproof power cord. A water inlet is arranged at the tail end of the pump body. An impeller is arranged on the pump body near the water inlet. A water outlet pipe is arranged on the upper side of the pump body. An alternating current motor is arranged at the top end of the pump body. The upper end of the pump body is provided with a support rod which is arranged on a rotating shaft at the top end of a rotating disc. The tail end of the rotating disc is fixed on a movable worktable. The utility model has the advantages of high water pump efficiency, large power, low cost, flexible operation and the like. The pump body is arranged on the movable worktables of hulls and the like, and can rotate in any direction, a user has no need of carrying or lifting the machine, the machine can move along with the ships, the large-range operation can be easily carried out, and therefore, the working strength of fishers is greatly lightened.

HENGCAI YE

374

Radiation tolerance in water bears.  

Science.gov (United States)

Tardigrades water bears are tiny invertebrates forming a phylum and inhabit various environments on the earth Terrestrial tardigrades enter a form called as anhydrobiosis when the surrounding water disappears Anhyydrobiosis is defined as an ametabolic dry state and followed by recovering their activity when rehydrated Anhydrobiotic tardigrades show incredible tolerance to a variety of extreme environmental conditions such as temperatures -273 r C to 151 r C vacuum high pressure 600 MPa and chemicals that include alcohols and methyl bromide In these views there have been some discussions about their potential for surviving outer space In the present study we demonstrated the survival limit not merely against gamma-rays but against heavy ions in the tardigrade Milnesium tardigradum in order to evaluate the effects of radiations on them The animals were exposure to 500 to 7000 Gy of gamma-rays or 500 to 8000 Gy of heavy ions 4 He in their hydrated or anhydrobiotic state The results showed that both of hydrated and anhydrobiotic animals have high radio-tolerance median lethal dose LD50 48 h of gamma-rays or heavy ions in M tardigradum was more than 4000 Gy indicating that this species is categorized into the most radio-tolerant animals We suggest that tardigrades will be suitable model animals for extremophilic multicellular organisms and may provide a survival strategy in extraterrestrial environments

Horikawa, D. D.; Sakashita, T.; Katagiri, C.; Watanabe, M.; Nakahara, Y.; Okuda, T.; Hamada, N.; Wada, S.; Funayama, T.; Kobayashi, Y.

375

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

Science.gov (United States)

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

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

2013-04-01

376

The Pietra Grande thrust (Brenta Dolomites, Italy): looking for co-seismic indicators along a main fault in carbonate sequences  

Science.gov (United States)

At present, pseudotachylytes (i.e. solidified frictional melts) are the only unambiguous geological record of seismic faulting. Even if pseudotachylytes are frequently observed along faults within crystalline rocks they are discovered along carbonate faults in very few cases only, suggesting that other chemico-physical processes than melting could occur (e.g. thermal decomposition). In order to investigate possible co-seismic indicators we study the Pietra Grande thrust, a carbonate fault in the Brenta Dolomites (Trentino, NE Italy), to analyse field structure, microtextures and composition of rocks from the principal slip plane, the fault core and the damage zone. The Pietra Grande thrust is developed within limestones and dolomitic limestones of Late Triassic-Early Jurassic age (Calcari di Zu and Monte Zugna Formations). The thrust, interpreted as a north-vergent décollement deeply connected with the major Cima Tosa thrust, is a sub-horizontal fault plane gently dipping to the North that mainly separates the massive Monte Zugna Fm. limestones (upper side) from the stratified Calcari di Zu Fm. limestones with intercalated marls (lower side). On the western face of the Pietra Grande klippe the thrust is continuously well-exposed for about 1 km. The main fault plane shows reddish infillings, which form veins with thicknesses between few millimetres to several decimetres. These red veins lie parallel to the thrust plane or in same cases inject lateral fractures and minor high-angle faults departing from the main fault plane. Veins have carbonate composition and show textures characterized by fine-grained reddish matrix with embedded carbonate clasts of different size (from few millimetres to centimetres). In some portions carbonate boulders (dimension of some decimetres) are embedded in the red matrix, while clast content generally significantly decreases at the vein borders (chilled margins). Red veins are typically associated with cohesive cataclasites and/or breccias of the fault zone. Host and fault rocks are locally folded, with fold axes having a rough E-W direction compatible with simultaneous thrust activation, suggesting deformation under brittle-ductile conditions. A late brittle deformation is testified by near-vertical fractures and strike-slip faults (WNW-directed) intersecting the whole thrust system. Field structure, microtextures, chemical and mineralogical compositions of host rocks, cataclasites and breccias are analysed. In particular, red veins are carefully compared with the very similar Grigne carbonate pseudotachylytes (Viganò et al. 2011, Terra Nova, vol. 23, pp.187-194), in order to evaluate if they could represent a certain geological record of seismic faulting of the Pietra Grande thrust.

Viganò, Alfio; Tumiati, Simone; Martin, Silvana; Rigo, Manuel

2013-04-01

377

Formation of an active thrust triangle zone associated with structural inversion in a subduction setting, eastern New Zealand  

Science.gov (United States)

We analyze a thrust triangle zone, which underlies the continental shelf of Hawke Bay, eastern New Zealand, within the Hikurangi subduction margin. This triangle zone differs from many other examples in that it is active, 90 km from the leading edge of the overriding plate, and formed due to polyphase deformation involving opposed dipping thrust duplex and backthrust, with the later structure forming in response to inversion of an extensional graben. The component structures of the zone mainly developed sequentially rather than synchronously. High-quality marine seismic reflection lines, tied to well and seabed samples, reveal the three-dimensional structure of the zone, together with its 25 Myr evolution and late Quaternary activity. The triangle zone occurs in the lateral overlap between a stack of NW dipping blind thrusts, and a principal backthrust, the Kidnappers fault. The NW dipping thrusts initiated in the early-middle Miocene during the early stages of subduction, with subsequent thrust duplex formation producing major uplift and erosion in the late Miocene-early Pliocene. The active backthrust formed during the late Miocene to early Pliocene as a thin-skinned listric extensional fault confined to the cover sequence. Structural inversion of the extensional fault commenced in the early-middle Pliocene, produced the backthrust and marks the formation of the thrust triangle zone. The thrust duplex and backthrust accrued strain following inversion; however, the later structure accommodated most of the surface deformation in the Quaternary. Section balancing of the triangle zone together with a detailed analysis of reverse displacements along the backthrust reveal spatial and temporal variations of strain accumulation on the two principal components of the zone. Although the formation of the triangle zone is strongly influenced by regional tectonics of the subduction system, these variations may also, in part, reflect local fault interaction. For example, high Quaternary displacement rates on the backthrust accounts for ˜70% of the displacement loss that occurs on the southern segments of the overlapping, Lachlan fault. Understanding the tectonic evolution of such complex, polyphase thrust triangle zones requires the preservation of growth strata that record sequential deformation history. In the absence of such data, synchroneity of opposed dipping thrusts in triangle zones cannot be assumed.

Barnes, Philip M.; Nicol, Andrew

2004-02-01

378

Aspects of the structural and late thermal evolution of the Redbank Thrust system, central Australia: constraints from the Speares Metamorphics  

International Nuclear Information System (INIS)

We present new data on the field geology and late thermal evolution of the Redbank Thrust system in the Arunta Block of central Australia. Geochronological and field data from the Speares Meta-morphics are also used to relate the thermal evolution of the Redbank Thrust system to the structural evolution of the region. We show that several stages in the evolution might be discerned. An originally sedimentary sequence was intruded by mafic intrusions and then deformed during partial melting to form the principal foliation observed in the region (D1). This sequence was then folded during D2 into upright folds with north- to northeast-plunging fold axes. These events are likely to correlate with the Strangways and/or Argilke and Chewings Orogenies known from previous studies. Subsequently, the Redbank Thrust was initiated during D3. This event is recognised by deflection of the host rocks into the shear zone and might therefore have been associated with a component of strike-slip motion. It occurred probably at or before 1500-1400 Ma. Subsequent north-over-south thrust motion in the Redbank Thrust formed the intense mylonitic fabric and folded the mylonitic fabric during D4 into asymmetric folds with shallow fold axes. New 40Ar/39Ar K-feldspar ages from three samples collected from variably deformed branches of the Redbank Thrust and undeformed rocks in the Speares Metamorphics suggest that most parts of the Redbank Thrust system cooled relatively slowly after metamorphism and deformation in the Mesoproterozoic so that the D4 thrusting might have been very long-lived. Minimum ages of the K-feldspar age spectra show that the entire region cooled below 200 deg C by approximately 300 Ma. Apatite fission track ages from nine samples show that cooling through the apatite partial annealing zone occurred during Cretaceous time (ca 150-70 Ma) and modelled cooling histories are consistent with the cooling rates obtained from the K-feldspar data. They indicate that final exhumation of the Redbank Thrust system occurred probably in response to erosion, possibly driven by rifting around the margins of Australia. Copyright (2003) Geological Society of Australia

2003-01-01

379

Interaction of basement-involved and thin-skinned tectonism in the Tertiary fold-thrust belt of central Spitsbergen, Svalbard  

Energy Technology Data Exchange (ETDEWEB)

The Tertiary fold-thrust belt in Oscar II Land, central Spitsbergen, consists of three major zones of distinct structural style: (1) a western basement-involved fold-thrust complex, (2) a central zone of thin-skinned fold-thrust units above a decollement in Permian evaporites, and (3) an eastern zone characterized by a frontal duplex system in the fold-thrust belt, bounded eastward by steep, basement-rooted reverse faults (Billefjorden and Lomfjorden fault zones) beneath subhorizontal platform strata. Offshore seismic data from Isfjorden (Statoil) confirm the threefold zonation and document thick-skinned and thin-skinned structural interactions in both the fold-thrust belt and the foreland section. The structural grain of the Tertiary fold-thrust belt partly coincides with the margin-bounding normal faults of these basins, suggesting that preexisting structures and stratigraphy controlled the Tertiary fold-thrust belt development. A kinematic evolution of the fold-thrust belt is invoked: (1) north-northeast-directed, bedding-parallel shortening, (2) major west-southwest-east-northeast shortening, with in-sequence foreland fold-thrust propagation, (3) basement-involved, west-southwest-east-northeast uplift in the eastern foreland zone, (4) eastward out-of-sequence propagation of thrusts, and (5) west-east extension in the hinterland. Our regional structural compilation map and synthesis of the central Spitsbergen transect advocates structural variation and linked basement-involved thrusting in the hinterland and thin-skinned/thick-skinned reactivation and out-of-sequence thrusting in the east (foreland), and is new compared with previous work of the region. The synthesis also raises several important new structural play concepts for investigating hydrocarbon prospects in Spitsbergen and adjacent regions; for example, inverted Carboniferous basins, and traps produced by tertiary thin- and thick-skinned contraction and reactivation structures.

Bergh, S.G. [Univ. of Tromso (Norway); Braathen, A. [Geological Survey of Norway, Trondheim (Norway); Andresen, A. [Univ. of Oslo (Norway)

1997-04-01

380

Experimental study on stacked type rubber bearing  

Energy Technology Data Exchange (ETDEWEB)

In order to improve performance of laminated rubber bearings used to isolate buildings from earthquake, a new type laminated rubber bearing has been developed which consists of steel plates and rubber sheets simply and alternately stacked. This stacked type laminated rubber bearing is specifically important for interfacial friction and fixing phenomenon between the steel plates and rubber sheets. An experimental study was performed on these problems. For specimens, a conventional bonded type rubber bearing and various types of the stacked type rubber bearing, in which three types of rubber sheet materials, and steel plates with different surface treatment were combined, were prepared. Static compressive tests, compressive alternate shearing tests, creep tests, and compression failure experiments were carried out. The results proved that the stacked type of the laminated rubber bearing has the ultimate strength of more than 2250 Kg/cm[sup 2] in terms of compressive stress, and the stable hysteresis property with a bi-linear loop which eliminates the occurrence of hardening phenomenon inherent in the bonded type of the laminated rubber bearing. 5 refs., 20 figs., 1 tab.

Takayama, M.; Tada, H.; Morita, K. (Fukuoka University, Fukuoka (Japan). Faculty of Engineering)

1992-09-01

 
 
 
 
381

Genetic control of biennial bearing in apple.  

UK PubMed Central (United Kingdom)

Although flowering in mature fruit trees is recurrent, floral induction can be strongly inhibited by concurrent fruiting, leading to a pattern of irregular fruiting across consecutive years referred to as biennial bearing. The genetic determinants of biennial bearing in apple were investigated using the 114 flowering individuals from an F(1) population of 122 genotypes, from a 'Starkrimson' (strong biennial bearer)×'Granny Smith' (regular bearer) cross. The number of inflorescences, and the number and the mass of harvested fruit were recorded over 6 years and used to calculate 26 variables and indices quantifying yield, precocity of production, and biennial bearing. Inflorescence traits exhibited the highest genotypic effect, and three quantitative trait loci (QTLs) on linkage group (LG) 4, LG8, and LG10 explained 50% of the phenotypic variability for biennial bearing. Apple orthologues of flowering and hormone-related genes were retrieved from the whole-genome assembly of 'Golden Delicious' and their position was compared with QTLs. Four main genomic regions that contain floral integrator genes, meristem identity genes, and gibberellin oxidase genes co-located with QTLs. The results indicated that flowering genes are less likely to be responsible for biennial bearing than hormone-related genes. New hypotheses for the control of biennial bearing emerged from QTL and candidate gene co-locations and suggest the involvement of different physiological processes such as the regulation of flowering genes by hormones. The correlation between tree architecture and