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1

Composite fan stator assembly  

SciTech Connect

A composite fan stator assembly is described for a gas turbine engine having at least two fan rotor stages, the composite stator assembly comprising: an annular composite fan case assembly including an access port, the fan case assembly circumferentially disposed around first and second fan rotor stage locations, a composite fan stator stage supported by and extending radially inward of the fan case assembly and axially disposed between the two fan rotor stage locations, the fan stator stage includes at least one removable vane segment accessible for removal through the access port for assembly and reassembly, the composite fan case assembly including a separable composite forward fan case assembly and a separable composite aft fan case assembly spaced axially aft of the forward fan case assembly, the forward fan case assembly being bolted to the aft fan case assembly, wherein the composite fan stator stage is axially and radially trapped and supported by the forward and aft fan case assemblies. A composite stator vane assembly comprising: a composite inner shroud, a composite outer shroud disposed radially outward of the inner shroud, a plurality of vanes disposed between the shrouds, the vanes including a suction side and a pressure side and radially inner and outer roots, the roots extending through platforms of corresponding ones of the inner and outer shrouds, four box-type attachment elements corresponding to curved suction and pressure sides of the inner and outer roots, the box-type attachment elements having two connected legs angled with respect to each other, a first one of the legs extending along, conforming to the curve of, and bonded to a corresponding one of the airfoil root sides, and a second one of the legs extending along and bonded to a composite shroud surface.

Donges, G.L.

1993-07-13

2

Banded electromagnetic stator core  

DOEpatents

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figures.

Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

1994-04-05

3

Banded electromagnetic stator core  

DOEpatents

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figs.

Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

1996-06-11

4

Electromagnetic pump stator coil  

SciTech Connect

An electrical stator coil for an electromagnetic pump includes a continuous conductor strip having first and second terminals at opposite ends thereof and an intermediate section disposed therebetween. The strip is configured in first and second coil halves, with the first coil half including a plurality of windings extending from the first terminal to the intermediate section, and the second coil half including a plurality of windings extending from the second terminal to the intermediate section. The first and second coil halves are disposed coaxially, and the first and second terminals are disposed radially inwardly therefrom with the intermediate section being disposed radially outwardly therefrom. 9 figs.

Fanning, A.W.; Dahl, L.R.

1996-06-25

5

Gas turbine engine stator assembly  

SciTech Connect

A gas turbine stator assembly is described comprising: an annular casing having an axial centerline axis and including an annular forward hook, an annular aft flange spaced axially from the forward hook, and a plurality of circumferentially aligned casing lugs spaced axially from the aft flange to define an annular casing groove there between, the casing lugs being circumferentially spaced apart from each other to define arcuate casing slots there between; a stator nozzle segment having an outer band, an inner band, and a plurality of circumferentially spaced apart vanes extending radially there between; the outer band having a forward hook supported by the casing forward hook, and an aft flange including a plurality of circumferentially spaced apart stator lugs defining there between arcuate stator slots, the stator lugs being disposed axially between the casing aft flange and the casing lugs in the casing groove, and aligned axially with respective casing lugs for axially aligning the stator slots with the casing slots; and an arcuate shroud having a plurality of axially extending shroud lugs spaced circumferentially apart from each other to define arcuate shroud slots there between, the shroud lugs being disposed axially through both the casing and stator slots, with the casing and stator lugs being disposed in the shroud slots for restraining rotation of the nozzle segment about the centerline axis.

Morgan, C.A.

1993-08-03

6

Stators with improved conductor assembly and method of making same  

DOEpatents

A stator includes a stator core, a plurality of slots, and a conductor. The plurality of slots are formed within the stator core. The conductor is disposed continuously within at least two of the plurality of openings.

Dang, Dang Dinh; Blissenbach, Rolf; Schauer, David; Wattleworth, John; Milani, Michael; Hatch, Erik

2013-07-30

7

Apparatus for Control of Stator Wakes.  

National Technical Information Service (NTIS)

This patent application discloses an apparatus that controls the wake of stator blades on an underwater vehicle. The apparatus comprises one or more stator blades, each with a movable trailing edge that when actuated in a controlled manner produces a peri...

D. N. Beal

2009-01-01

8

Nonlinearly Stacked Low Noise Turbofan Stator.  

National Technical Information Service (NTIS)

The present invention provides a nonlinearly stacked low noise turbofan stator vane. The stator is in an axial fan or compressor turbomachinery stage that is comprised of a collection of vanes whose highly three-dimensional shape is selected to reduce rot...

D. S. Weir J. A. Gunara K. B. Kontos N. A. Nolcheff W. B. Schuster

2005-01-01

9

Stator fault modeling in induction motors  

Microsoft Academic Search

In this paper a model of an induction motor affected by stator faults is presented. Two different types of faults are considered, these are; disconnection of a supply phase, and inter-turn and turn-turn short circuits inside the stator. The output of the derived model is compared to real measurements from a specially designed induction motor. With this motor it is

Jesper S. Thomsen; C. S. Kallesoe

2006-01-01

10

Fundamental Investigation of Circumferentially Varying Stator Cascades  

NASA Astrophysics Data System (ADS)

The fundamentals of circumferentially varying stator cascades and their interactions with a downstream fixed pitch propeller were investigated experimentally utilizing multiple measurement techniques. The flow physics associated with the isolated circumferentially varying, or cyclic, stator cascade was studied in a wind tunnel environment through string tuft flow visualization, 2-D PIV, Stereoscopic PIV, and static surface pressure measurements. The coupled wake physics of the cyclic stator cascade with propeller were then investigated in a water tunnel using Stereo PIV. Finally, the global performance of components and the coupled system were quantified through force and moment measurements on the model in the water tunnel. A cyclic distribution of the stators' deflections resulted in non-axisymmetric distributions of the surface pressure and the flow field downstream of the stator array. In the model near wake the flow field is associated with secondary flow patterns in the form of coherent streamwise vortical structures that can be described by potential flow mechanisms. The collective pitch distribution of the stators produces a flow field that resembles a potential Rankine vortex, whereas the cyclic pitch distribution generates a flow pattern that can be described by a potential vortex pair in a cross flow. The stator distribution alone produces a significant side force that increases linearly with stator pitch amplitude. When a propeller is incorporated downstream from the cyclic cascade the side force from the stator cascade is reduced, but a small vertical force and pitching moment are created. The generation of these secondary forces and moments can be related to the redistribution of the tangential flow from the cyclic cascade into the axial direction by the retreating and advancing blade states of the fixed pitch propeller.

Farnsworth, John A. N.

11

Turbine Rotor/Stator Flowfield Analysis.  

National Technical Information Service (NTIS)

A numerical study of the unsteady aerodynamic and thermal environment associated with axial turbine stages is presented. Computations are performed using a modification of the ROTOR1 rotor/stator interaction code. Two different turbine states are analyzed...

L. Griffin

1989-01-01

12

An evaluation of model-based stator resistance estimation for induction motor stator winding temperature monitoring  

Microsoft Academic Search

Summary form only given, as follows. In this paper, the feasibility of using an estimate of the stator resistance (Rs) as an indicator of stator winding temperature (Ts) is evaluated. The advantages of resistance-based temperature monitoring over conventional thermal model-based methods are presented. Since obtaining an accurate estimate of Rs is critical for this approach, an investigation of existing Rs

Sang-Bin Lee; T. G. Habetler; R. G. Harley; D. J. Gritter

2002-01-01

13

An evaluation of model-based stator resistance estimation for induction motor stator winding temperature monitoring  

Microsoft Academic Search

In this paper, the feasibility of using an estimate of the stator resistance (Rs) as an indicator of stator winding temperature (Ts) is evaluated. The advantages of resistance-based temperature monitoring over conventional thermal model-based methods are presented. Since obtaining an accurate estimate of Rs is critical for this approach, an investigation of existing Rs estimation schemes, and an analysis showing

Sang-Bin Lee; Thomas G. Habetler; Ronald G. Harley; David J. Gritter

2002-01-01

14

An Evaluation of Model-Based Stator Resistance Estimation for Induction Motor Stator Winding Temperature Monitoring  

Microsoft Academic Search

The feasibility of using an estimate of the stator resistance (Rs) as an indicator of stator winding temperature (Ts) is evaluated. The advantages of resistance-based temperature monitoring over conventional thermal model-based methods are presented. Since obtaining an accurate estimate of Rs is critical for this approach, an investigation of existing Rs estimation schemes, and an analysis showing the sensitivity of

S. B. Lee; T. G. Habetler; R. G. Harley; D. J. Gritter

2002-01-01

15

Evaluation of Ceramics for Stator Application: Gas Turbine Engine Report.  

National Technical Information Service (NTIS)

Current ceramic materials, component fabrication processes, and reliability prediction capability for ceramic stators in an automotive gas turbine engine environment are assessed. Simulated engine duty cycle testing of stators conducted at temperatures up...

P. H. Havstad W. Trela

1978-01-01

16

Control rod drive mechanism stator loss of coolant test  

Microsoft Academic Search

This report documents the stator loss of coolant test conducted at HEDL on the lead unit Control Rod Drive Mechanism (CRDM) in February, 1977. The purpose of the test was to demonstrate scram capability of the CRDM with an uncooled stator and to obtain a time versus temperature curve of an uncooled stator under power. Brief descriptions of the test,

L. Besel; R. Ibatuan

1977-01-01

17

PERFORMANCE ANALYSIS OF THE REPULSION MOTOR CONTROLLED VIA STATOR TRIAC  

Microsoft Academic Search

This paper investigates the solid state speed control of a repulsion motor using a triac in the stator circuit. The speed control is accomplished by varying the triac firing angle.In addition, this paper investigates the harmonic contents of the rotor current, stator current and stator voltage. The waveforms of these variables were generated and then analyzed numerically for their harmonic

ZIYAD M. SALAMEH; CHAHEE P. CHO

1990-01-01

18

LES of open rotor–stator flow  

Microsoft Academic Search

Computer experiments (LES) of the axisymmetric and statistically steady turbulent flow between a rotating and a fixed disk have been performed. This flow is a representative of the flow in an unshrouded rotor–stator configuration. The flow is characterized only by a local Reynolds number and a local gap ratio, provided that the distance from the rotation axis is sufficiently large

Helge I. Andersson; Magne Lygren

2006-01-01

19

Heat transfer in rotor/stator cavity  

NASA Astrophysics Data System (ADS)

In the paper we analyze the results of DNS/LES of the flow with heat transfer in the rotor/stator cavity. The rotor and the outer cylinder are heated. Computations have been performed for wide range of Reynolds numbers and aspect ratios. Computations are based on the efficient pseudo-spectral Chebyshev-Fourier method. In LES we used a Lagrangian dynamic subgrid-scale model of turbulence. Analysis allowed to check the influence of the aspect ratio and Reynolds number on the statistics and the structure of the flow. We analyzed all six Reynolds stress tensor components, turbulent fluctuations, three turbulent heat fluxes and different structural parameters which can be useful for modeling purposes. The distributions of Nusselt numbers obtained for different Re and aspect rations along disks are given. We also investigated influence of thermal Rosssby number as well as distributions of temperature along heated disk on statistics. Computations have shown that turbulence is mostly concentrated in the stator boundary layer with a maximum at the junction between the stator and the outer cylinder. The results are compared to the experimental and numerical data taken from literature.

Tuliszka-Sznitko, Ewa; Majchrowski, Wojciech; Kie?czewski, Kamil

2011-12-01

20

Reconstruction of the Switched Reluctance Motor Stator  

NASA Astrophysics Data System (ADS)

The paper re-designs the conventional 6/8 switched reluctance motor (SRM) by a particular way to minimize the losses. The flux loops are shortened by making each two stator teeth incorporated in one magnetic circuit only. Subsequently the flux does not cross in some iron parts of the stator core backs. These unused iron sections are taken off consequently the iron losses decreased. Now the stator consists of three separated sections and they are fixed inside non-magnetic cylinder. The copper losses also are decreased because less copper windings are used to produce the same amount of the output torque as the flux paths become short then the flux density increases. The analysis and comparison of the 6/8 SRM before and after the re-design process are presented. A m files Matlab software is used to simulate the dynamic performance. Then the paper proceeds to examine different control techniques to the new design. The hysteresis and PI controllers are used as classical method to control the SRM. Then the artificial neural network (ANN) is used to test the new control techniques.

El-Kharashi, Eyhab; Hassanien, Hany M.

2012-01-01

21

Effect of toothless stator design and core and stator conductors eddy current losses in permanent magnet generators  

Microsoft Academic Search

Some advantages of toothless stator design in high-speed permanent magnet generators are presented. A computer-aided method was implemented to study the effect of stator teeth on the eddy current loss in the stator conductors as well as the core loss in the laminations of high-speed permanent magnet generators. The computer-aided method was applied to a 75 kVA, 208 V, 400

A. A. Arkadan; R. Vyas; J. G. Vaidya; M. J. Shah

1992-01-01

22

A degradation model of synchronous generator stator insulation  

Microsoft Academic Search

In this work the authors present a degradation model of generator stator insulation to compute failure probabilities. This may in turn be used to develop risk-based maintenance for synchronous generators. First, generators different failure modes were identified and studied. The most common failure mode encountered was failure of the stator winding insulation. Following Simoni's insulation deterioration model, a mathematical-theoretical insulation

L. M. Monge-Guerrero; A. A. Irizarry-Rivera

2005-01-01

23

Stator Vibration Analysis of Bearingless Switched Reluctance Motors  

Microsoft Academic Search

Radial magnetic force acts on the motor stator cause large vibration and acoustic noise, that have limit the application of switched reluctance motors (SRMs). They can be aggravated when there is unbalanced force due to rotor eccentricity. This paper analyzed the function of bearingless technique in compensating the unbalanced magnetic attraction force; Then the stator radial force mathematic model of

Yang Yan; Deng Zhiquan; Zhang Qianying; Wang Xiaolin

2010-01-01

24

On-line stator and rotor resistance estimation for induction motors  

Microsoft Academic Search

A ninth-order estimation algorithm is designed which provides online exponentially convergent estimates of both rotor and stator resistance for induction motors, when persistency of excitation conditions are satisfied and the stator current integrals are bounded, on the basis of rotor speed, stator voltages, and stator current measurements. Rotor flux is also asymptotically recovered. Experimental tests are reported which show that:

Riccardo Marino; Sergei Peresada; Patrizio Tomei

2000-01-01

25

Effects of toothless stator design on dynamic model parameters of permanent magnet generators  

Microsoft Academic Search

The effects of toothless stator design on the dynamic model parameters of permanent magnet (PM) generators are presented. These parameters, which include inductances and induced back EMFs, are determined for a 75 kVA, 208 V, 400 Hz, two-pole, permanent magnet generator. Two particular stator designs, a toothless stator, and a conventional type stator (with iron teeth), are considered. The method

A. A. Arkadan; R. Vyas

1993-01-01

26

Theoretical Calculation of Stability for NASA Stage 57 Stator  

NASA Astrophysics Data System (ADS)

The stability of 595 operational points, belonging to 25 different experimental arrangements of the NASA stage 57, is studied by means of a theoretical calculation based on a theorem recently presented in the scientific literature. This large number of tests is used for checking the results of the theory for a wide variation of the operational and the design parameters. This study completes a previous one by adding the calculations for the stator. Both rotor and stator results are related with the stage stability. While only seven test points appear as potentially unstable due to the rotor, nine test points do due to the stator.

Benavides, Efrén M.; Juste, Gregorio L.

2011-09-01

27

Turbulence statistics in an open rotor-stator configuration  

Microsoft Academic Search

Turbulence statistics, including complete budget data for the six individual components of the Reynolds stress tensor, have been compiled from a direct numerical simulation of the three-dimensional flow in an open rotor-stator configuration. Comparisons between turbulence statistics near the two disks and in plane Couette flow showed that the stator-side data closely resemble those found in Couette flow. At the

M. Lygren; H. I. Andersson

2002-01-01

28

INCUBACION ANAEROBICA DEL SUELO COMO DIAGNOSTICO DE LA RESPUESTA A NITROGENO DEL MAIZ BAJO SIEMBRA DIRECTA  

Microsoft Academic Search

-1 then the yield increment = 72,5 - 1,38 Nan, if Nan > 48.mg kg -1 the yield increment = 6 %). Nan was related with the time (years) since the last pasture (r 2 = 0.39). These results suggest that Nan probably is associated with light carbon fractions and can be used to explain the response of maize to

PA CALVIÑO; HE ECHEVERRÍA

29

Stator flux based space-vector modulation and closed loop control of the stator flux vector in overmodulation into six-step mode  

Microsoft Academic Search

This paper presents closed loop control of stator flux vector in a wide operating range that can be used in torque control. A predictive control achieves zero phase error at constant switching frequency. Space vector modulation based on stator flux error vector is used to achieve control of stator flux over the entire range including overmodulation and six-step. During dynamics

Anshuman Tripathi; Ashwin M. Khambadkone; Sanjib K. Panda

2004-01-01

30

DIABETE MELLITO E DEFICIT ERETTILE: AGGIORNAMENTO DIAGNOSTICO-TERAPEUTICO  

Microsoft Academic Search

Il deficit erettile colpisce la popolazione diabetica più precocemente rispetto alla popolazione generale ed è un'importante concausa della riduzione della qualità della vita del paziente stesso. La prevalenza di deficit eret- tile nel diabete in Italia è del 35,8%; i fattori di rischio principali, oltre alla durata della patologia diabetica, sono il grado di compenso glicometabolico e la presenza di

M. TAGLIABUE; L. ROLLE; F. RAGNI; C. DI BISCEGLIE

31

Stator-Induced Circumferentially-Varying Preswirl Propulsor  

NASA Astrophysics Data System (ADS)

A propuslor capable of producing maneuvering forces in all directions effectively eliminates the need for additional control surfaces. Side forces can be generated by the propeller through the variation of the inflow swirl velocity to a conventional propeller. These control forces are generated based on the same geometric principles as a helicopter swash-plate. Instead of cyclically adjusting the propeller blade pitch angle, the relative pitch angle of a fixed pitch propeller is cyclically altered through a preswirled inflow generated by an upstream stator row. Experiments were conducted in a wind tunnel to quantify the effectiveness of an upstream stator row to generate a circumferentially varying swirled flow. Global flow measurements were acquired through static pressure and PIV measurements on a simplified propulsor model. From these and future measurements a full understanding of the fluidic interactions associated with the non-uniform upstream stator row and the propeller can be made.

Farnsworth, John; Amitay, Michael; Beal, David; Huyer, Stephen

2008-11-01

32

Turbulence statistics in an open rotor-stator configuration  

NASA Astrophysics Data System (ADS)

Turbulence statistics, including complete budget data for the six individual components of the Reynolds stress tensor, have been compiled from a direct numerical simulation of the three-dimensional flow in an open rotor-stator configuration. Comparisons between turbulence statistics near the two disks and in plane Couette flow showed that the stator-side data closely resemble those found in Couette flow. At the rotor side rotational production terms due to the Coriolis force made only modest contributions to the budget equations for the Reynolds stresses, but the subtle influence of system rotation was by no means negligible.

Lygren, M.; Andersson, H. I.

2002-03-01

33

Stator winding fault diagnosis in induction motors using the dq current trajectory mass center  

Microsoft Academic Search

This paper proposes the use of the park transformation mass center applied to the stator currents as a method for diagnosing the occurrence of stator winding faults in induction motor. Induction motor stator currents are first measured and recorded. Then, the park transform is applied to the obtained currents in order to obtain a specific pattern that allows the identification

V. Fernão Pires; Tito G. Amaral; J. F. Martins

2009-01-01

34

REDUCTION OF UNSTEADY STATOR–ROTOR INTERACTION USING TRAILING EDGE BLOWING  

Microsoft Academic Search

An aeroacoustic investigation was performed to assess the effects of adding mass flow at the trailing edges of stators upstream of an aircraft engine simulator. By using trailing edge blowing to minimize the shed wakes of the stators, the flow into the rotor was made more uniform, hence reducing the unsteady stator–rotor interaction. In these experiments, a reduced number of

THOMAS A. LEITCH; C. A. SAUNDERS; W. F. NG

2000-01-01

35

Reduction of Unsteady Stator-Rotor Interaction Using Trailing Edge Blowing  

Microsoft Academic Search

An aeroacoustic investigation was performed to assess the effects of adding mass flow at the trailing edges of stators upstream of an aircraft engine simulator. By using trailing edge blowing to minimize the shed wakes of the stators, the flow into the rotor was made more uniform, hence reducing the unsteady stator-rotor interaction. In these experiments, a reduced number of

Thomas A. Leitch; C. A. Saunders; W. F. Ng

2000-01-01

36

Modeling and vector control of synchronous reluctance motors including stator iron loss  

Microsoft Academic Search

The influence of the stator iron loss cannot be neglected since the high-speed operation and precision torque control of AC motors are required. This paper presents the modeling and vector control of synchronous reluctance motors including the stator iron loss. The stator iron loss is modeled by additional windings on the d-q axes, and is introduced as an equivalent iron

Katsumi Uezato; Tomonobu Senjyu; Yoshikatsu Tomori

1994-01-01

37

Design and control of a novel bearingless SRM with double stator  

Microsoft Academic Search

In this paper, a novel bearingless switched reluctance motor (BLSRM) with double stator is introduced. Inside stator generates radial force to suspend the rotor. Outside stator produces rotational torque. In order to calculate the characteristics of the proposed structure, a finite element model is used. From the analysis, the proposed BLSRM has linear characteristic of radial force, decoupling control between

Wei Peng; Fengge Zhang; Jin-Woo Ahn

2012-01-01

38

Noise prediction of rotor-stator interaction for fan\\/compressor  

Microsoft Academic Search

A method for predicting the noise generated by rotor wake-stator interaction is presented by solving the generalized Lighthill equation. First, a wake model behind the rotor blades is given. Then, the unsteady forces on the stator blades can be computed, using a two-dimensional compressible unsteady computation method. The rotor stator interaction noise is then obtained, considering the effects of the

Xiaofeng Sun; Zongan Hu; Shen Zhou

1989-01-01

39

Measurement of attitude angles of single stator multi-degrees of freedom ultrasonic motor  

Microsoft Academic Search

In order to measure the attitude angles of our ultrasonic motor, a compact single stator multi-degree-of freedom (DOF) ultrasonic motor with a cylindrical stator and a spherical rotor is designed with one OEM encoder and 2D PSD (Position Sensitive Detector) sensor. The spherical rotor is rotated around three perpendicular axes by three natural vibrations excited on the stator. The OEM

Wu-Fal Liu; Zheng Tao; Lin-Na Zhang; Jian-She Gao; Feng-Xia Zhao; Peng Zhen

2010-01-01

40

A digital technique for stator winding protection of synchronous generators  

Microsoft Academic Search

This paper describes a digital technique for detecting internal faults in stator windings of synchronous generators. The technique uses positive- and negative-sequence models of the synchronous generator, and voltages and currents measured at the generator terminals. It does not need information concerning the machine parameters and is applicable to all types of generators, irrespective of their size. Fault discrimination characteristics

T. S. Sidhu; B. Sunga; M. S. Sachdev

1996-01-01

41

Decarburisation of interlocked and laser welded stator and rotor cores  

NASA Astrophysics Data System (ADS)

Assembled rotor and stator cores were annealed in an industrial furnace. The final carbon content of the annealed cores was identical, irrespective of the position of the lamination in the assembled core, the initial carbon content or the geometry of the laminations. It is concluded that it is not necessary to use pre-decarburised semi processed electrical steels for automatic assembly.

Standaert, C.; Eloot, K.; de Paepe, A.; Wokowski, P.

1996-07-01

42

Axial-Flow Compressor Rotor-Stator Interaction.  

National Technical Information Service (NTIS)

In a typical axial-flow compressor stage, rotor wakes mix out and thus they lose energy downstream of each rotor blade trailing edge. Furthermore, rotor wake fluid is continuously severed by downstream stator blades into convected wake segments that inter...

J. L. Hansen T. H. Okiishi

1985-01-01

43

Analysis of Wake-Stator Interaction in Airfoil Cascades.  

National Technical Information Service (NTIS)

A computational study has been conducted in order to provide insight into the details of the unsteady flow in the leading-edge region of airfoil cascades during wake-stator interaction. The calculations are performed at off-design operating conditions, si...

M. Barnett D. L. Sondak

1995-01-01

44

Influence of rotor slot wedges on stator currents and stator vibration spectrum of induction machines: a transient finite-element analysis  

Microsoft Academic Search

The stator currents and stator vibration spectrum of a 45-kW four-pole induction machine is computed using a transient two-dimensional finite-element analysis. The analysis is performed for two different rotor geometries: with open and with closed rotor slots. Open rotor slots increase the harmonic content of the air gap field and also the harmonic content of the stator currents. Open rotor

Koen Delaere; Ronnie Belmans; Kay Hameyer

2003-01-01

45

SQUID measurements for thermal aging of stator windings  

NASA Astrophysics Data System (ADS)

Conventional non-destructive diagnostic tests for aging of dielectric insulation on high voltage cables and stator windings are limited to measurements of lumped electrical parameters. Commonly used step voltage tests may lead to breakdown of the insulation and damage to the system. A map of spatial distribution of the electrical properties of the cable may provide the information about the age-related failure. Our approach uses a Superconducting Quantum Interference Device (SQUID) magnetometer to map the magnetic field due to charging current through the cable. We have performed a series of experiments which demonstrate that we can image magnetically the distribution of charging currents and the perturbations in this distribution that result from localized changes in dielectric constant, and we can discriminate thermally aged stator windings from new ones. .

Ma, Yu Pei; Wikswo, John P.; Fitzpatrick, Gerald

2001-04-01

46

Propagation of surges in stator winding of large AC motors  

Microsoft Academic Search

The impedance and admittance matrices of the ten-turn coils of a 3.3 kV, 1 MW induction motor stator winding are calculated using a finite-element package. Using multiconductor transmission line theory the Z and Y matrices are manipulated to explain the modal propagation of step-fronted surges entering the winding. Some modes are seen to have similar structures in both the slot

H. Oraee

1989-01-01

47

Noise prediction of rotor-stator interaction for fan/compressor  

NASA Astrophysics Data System (ADS)

A method for predicting the noise generated by rotor wake-stator interaction is presented by solving the generalized Lighthill equation. First, a wake model behind the rotor blades is given. Then, the unsteady forces on the stator blades can be computed, using a two-dimensional compressible unsteady computation method. The rotor stator interaction noise is then obtained, considering the effects of the compressor tube on the noise fields. The total noise power depends on the following parameters: stagger angle and chord of stator blade, spacing of rotor/stator, Mach number, rotor speed, and wake behind the rotor blades. Some numerical results are given to analyze the effect of the spacing of rotor-stator on the noise radiation. The estimated results show a reasonable agreement with the experimental data.

Sun, Xiaofeng; Hu, Zongan; Zhou, Shen

1989-01-01

48

A reduced-order position observer with stator-resistance adaptation for synchronous reluctance motor drives  

Microsoft Academic Search

A reduced-order position observer with stator-resistance adaptation is applied for motion-sensorless synchronous reluctance motor drives. A general analytical solution for the stabilizing observer gain and stability conditions for the stator-resistance adaptation are given. The local stability of the position and stator-resistance estimation is guaranteed at every operating point except the zero frequency, if inductances are known accurately. The observer design

Toni Tuovinen; Marko Hinkkanen; Lennart Harnefors; Jorma Luomi

2010-01-01

49

Detection of Stator Faults in Induction Machines Using Residual Saturation Harmonics  

Microsoft Academic Search

Stator fault is one of the most commonly occurring faults in ac machines. Recent estimates suggest that 30%-40% of all reported induction machine faults are stator fault related. Going by the number of occurrences, the position of stator faults is only second to bearing-related faults. Third harmonic line currents, which are caused by the interaction of a reverse-rotating field and

Subhasis Nandi

2006-01-01

50

Novel stator design of fan motors using soft magnetic composites  

NASA Astrophysics Data System (ADS)

Cooling fans are an important device needed in consumer electronic products. To enhance the performance of cooling fans, this paper presents a novel brushless dc motor with a three dimensional stator structure using soft magnetic composite to reduce the hub size and allow more airflow. Four models are designed and their output characteristics are compared using finite element simulation. From the results, one of them is selected for prototyping whose performance appears to meet the requirement. The prototype has a 10% smaller diameter than that of conventional types. Moreover, the operation test shows that the required performance is achieved.

Hsu, Yu-Sheng; Tsai, Mi-Ching; Hsieh, Min-Fu

2008-04-01

51

Flux observer with online tuning of stator and rotor resistances for induction motors  

Microsoft Academic Search

This paper proposes an adaptive flux observer for induction motors, where stator and rotor resistances are estimated in online environments. The variation of motor parameters during operation degrades the performance of the controller and the flux observer. Among the parameters of induction motors, rotor resistance is a crucial one for flux estimation, and stator resistance also becomes critical in the

Seok Ho Jeon; Kwang Kyo Oh; Jin Young Choi

2002-01-01

52

New General MRAS Adaptive Scheme to Estimate Stator and Rotor Resistance of Induction Motors  

Microsoft Academic Search

In this paper, a new adaptive scheme for simultaneous on-line stator and rotor resistance estimation of induction motors is proposed. This method is based on the adaptive control theory of model reference adaptive system (MRAS) approach with Luenberger observer. And the stability of the observer with stator and rotor resistance estimation from the proposed adaptive scheme is proved by the

Han Li; Wen Xuhui; Chen Guilan

2006-01-01

53

Optimal Number of Stator Poles for Compact Active Radial Magnetic Bearings  

Microsoft Academic Search

We present a method for finding the optimal number of stator poles for active radial magnetic bearings that minimizes the stator outside diameter. We use magnetic circuit analysis to determine the number of turns of wire to generate the worst case load capacity within limits of coil currents and flux densities. Using the analysis, we developed six types of magnetic

Koichi Matsuda; Yoichi Kanemitsu; Shinya Kijimoto

2007-01-01

54

Magnetic Effects of DC Signal Injection on Induction Motors for Thermal Evaluation of Stator Windings  

Microsoft Academic Search

Active thermal protection techniques have been pro- posed for the thermal protection of induction motors. By injecting dc signals, the dc model of the induction motors can be used to estimate the stator winding resistance and, thus, the average stator winding temperature. The injected dc signals may lead to unbalanced magnetic saturation, which may degrade a motor's performance and may

Pinjia Zhang; Yi Du; Thomas G. Habetler; Bin Lu

2011-01-01

55

A Control Method for Asynchronous Motor Based on Stator Current Vector Orientation  

Microsoft Academic Search

The stator flux model is different at high speed and low speed for the direct torque control (DTC), so the structure of DTC system is complex. Aiming at this issue, a new scheme of induction motor drive is proposed. The core idea is controlling the angle between the stator current vector and the rotor flux vector. It doesn't need the

Jiaquan Lin; Yi Zang; Jun Zhang; Xu Wang; Zongfu Liu

2006-01-01

56

Stator Current Harmonic Control With Resonant Controller for Doubly Fed Induction Generator  

Microsoft Academic Search

Voltage harmonics in the grid can introduce stator current harmonics in a doubly fed induction generator (DFIG) wind turbine system, which may potentially impact the generated power quality. Therefore, wind turbine current controllers need to be designed to eliminate the impact of grid voltage harmonics, especially low-order harmonics. This paper proposes a stator current harmonic suppression method using a sixth-order

Changjin Liu; Frede Blaabjerg; Wenjie Chen; Dehong Xu

2012-01-01

57

Study of aging characteristics of generator stator insulation based on temperature spectrum of dielectric dissipation factor  

Microsoft Academic Search

In this paper, accelerated multi-factor aging tests in laboratory have been conducted on the stator bars of a large generator. During the period of aging, the temperature spectra of dielectric dissipation factor tan ? of stator insulation were employed to investigate aging characteristics of insulation materials. Test results showed that the peak temperature Tm of the tan ? -T curve

Xiaoqin Ma; Xiaowei Ma; Bo Yue; Weisheng Lu; Hengkun Xie

2003-01-01

58

Superconducting electromechanical rotating device having a liquid-cooled, potted, one layer stator winding  

DOEpatents

A superconducting electromechanical rotating (SER) device, such as a synchronous AC motor, includes a superconducting field winding and a one-layer stator winding that may be water-cooled. The stator winding is potted to a support such as the inner radial surface of a support structure and, accordingly, lacks hangers or other mechanical fasteners that otherwise would complicate stator assembly and require the provision of an unnecessarily large gap between adjacent stator coil sections. The one-layer winding topology, resulting in the number of coils being equal to half the number of slots or other mounting locations on the support structure, allows one to minimize or eliminate the gap between the inner radial ends of adjacent straight sections of the stator coilswhile maintaining the gap between the coil knuckles equal to at least the coil width, providing sufficient room for electrical and cooling element configurations and connections. The stator winding may be potted to the support structure or other support, for example, by a one-step VPI process relying on saturation of an absorbent material to fill large gaps in the stator winding or by a two-step process in which small gaps are first filled via a VPI or similar operation and larger gaps are then filled via an operation that utilizes the stator as a portion of an on-site mold.

Dombrovski, Viatcheslav V. (Willoughby Hills, OH); Driscoll, David I. (South Euclid, OH); Shovkhet, Boris A. (Beachwood, OH)

2001-01-01

59

A Review of Results From Thermal Cycling Tests of Hydrogenerator Stator Windings  

Microsoft Academic Search

Thermal cycling of generators, occurring during in- termittent operation of power stations, increases the thermome- chanical stress on the stator groundwall insulation and can, there- fore, contribute to failure of the generator. Thermal cycling stresses can, to some extent, be replicated and accelerated in laboratory tests. Such tests are performed to ascertain whether a new stator winding insulation system can

Maren Istad; Magne Runde; Arne Nysveen

2011-01-01

60

Stator insulation problems associated with low voltage and medium voltage PWM drives  

Microsoft Academic Search

About 15 years ago, the short risetime pulses caused by voltage source, pulse width modulated converters were first recognized as a cause of stator winding insulation failure in low voltage motors. The root cause was found to be the large number of PWM voltage pulses from the drive, which caused partial discharges between turns in the stator. These discharges eventually

G. C. Stone; I. M. Culbert; B. A. Lloyd

2007-01-01

61

Experimental contribution to the study of secondary flows in centrifugal turbopump stator components  

Microsoft Academic Search

The flow characteristics in centrifugal turbomachines is investigated. Particular attention is given to the turbomachine stator components. The purposes of the study were: to validate the flow model for centrifugal turbopumps; to perform flow measurements on a test bed model in order to acquire accurate stator and U-bend pipe flow data; and to acquire local flow data for future numerical

Sahraoui Bouziane

1992-01-01

62

Air-gap flux density optimization in dual stator winding induction machines  

Microsoft Academic Search

The vector control of the dual stator winding induction machine is investigated in this paper. A simplified model for the dual stator winding induction machine considering it as two different induction machines coupled by the rotor can be used to study different control algorithms. The validity of the model will be proven. This model can only be considered if the

Juan M. Guerrero; Olorunfemi Ojo

2008-01-01

63

Stator resistance identification using artificial intelligent technique for the adaptive controller of magnetically saturated induction motor  

Microsoft Academic Search

The problem of controlling the induction motor ?-model with magnetic saturation is considered using an adaptive controller with stator current and rotor speed measurement. The new in this paper that in the previous work, only the rotor resistance and load torque can be adapted using the controller but in this work, using artificial intelligent technique, an adaptation of the stator

Ismail Mohamed Mahmoud

2010-01-01

64

Experimental works and analysis for influence of stator slot number on performance of interior PM motor  

Microsoft Academic Search

This paper deals with experimental works and analysis for influence of stator slot number on performance of interior PM (IPM) motor. First, for a conventional 6-pole IPM rotor, stators with 18, 27 and 36 slots satisfied with same required and restricted conditions are designed. And then, performances and parameters of each IPM motor such as cogging torque, torque ripple, d-

Jang-Young Choi; Kyoung-Jin Ko; Seok-Myeong Jang

2010-01-01

65

Models for bearing damage detection in induction motors using stator current monitoring  

Microsoft Academic Search

This paper describes new models for the influence of rolling-element bearing faults on induction motor stator current. Bearing problems are one major cause for drive failures. Their detection is possible by vibration monitoring of characteristic bearing frequencies. As it is possible to detect other machine faults by monitoring the stator current, a great interest exists in applying the same method

M. Blodt; Pierre Granjon; Bertrand Raison; Gilles Rostaing

2004-01-01

66

Models for Bearing Damage Detection in Induction Motors Using Stator Current Monitoring  

Microsoft Academic Search

This paper describes a new analytical model for the influence of rolling-element bearing faults on induction motor stator current. Bearing problems are one major cause for drive failures. Their detection is possible by vibration monitoring of characteristic bearing frequencies. As it is possible to detect other machine faults by monitoring the stator current, a great interest exists in applying the

Martin Blodt; Pierre Granjon; Bertrand Raison; Gilles Rostaing

2008-01-01

67

Detection of leaks in a water-cooled generator stator bar using perfluorocarbon tracers  

Microsoft Academic Search

A generator stator bar with a suspected leak was removed from the ConEdison Ravenswood power plant and shipped to an independent laboratory for hydraulic pressure testing. The test failed to demonstrate the location and magnitude of leaks. The stator bar was subsequently investigated at Brookhaven's Tracer Technology Center. Pressurization with 3 ppM PMCP (perfluoromethylcyclopentane) in hydrogen as carrier gas revealed

W. M. Loss; R. N. Dietz; G. I. Senum

1989-01-01

68

Effects of axial and radial-gap spacing on the local heat transfer of a shrouded rotor-stator system  

Microsoft Academic Search

Unlike the free disk in which heat transfer is primarily affected by rotational speed, heat transfer in rotor-stator systems is influenced by the operating conditions as well as system geometry. In a rotor-stator system with no radial shroud, commonly referred to as an open rotor-stator, Kreith et al. (1959, 1963) and Metzger (1970) demonstrated that the presence of the stator

M. K. Chyu; D. J. Bizzak

1992-01-01

69

Tuning the stator resistance of induction motors using artificial neural network  

SciTech Connect

Tuning the stator resistance of induction motors is very important, especially when it is used to implement direct torque control (DTC) in which the stator resistance is a main parameter. In this paper, an artificial network (ANN) is used to accomplish tuning of the stator resistance of an induction motor. The parallel recursive prediction error and backpropagation training algorithms were used in training the neural network for the simulation and experimental results, respectively. The neural network used to tune the stator resistance was trained on-line, making the DTC strategy more robust and accurate. Simulation results are presented for three different neural-network configurations showing the efficiency of the tuning process. Experimental results were obtained for the one of the three neural-network configuration. Both simulation and experimental results showed that the ANN have tuned the stator resistance in the controller to track actual resistance of the machine.

Cabrera, L.A.; Elbuluk, M.E.; Husain, I. [Univ. of Akron, OH (United States). Dept. of Electrical Engineering

1997-09-01

70

Dynamics in large generators due to oval rotor and triangular stator shape  

NASA Astrophysics Data System (ADS)

Earlier measurements in large synchronous generators indicate the existence of complex whirling motion, and also deviations of shape in both the rotor and the stator. These non-symmetric geometries produce an attraction force between the rotor and the stator, called unbalanced magnetic pull (UMP). The target of this paper is to analyse responses due to certain deviations of shape in the rotor and the stator. In particular, the perturbation on the rotor is considered to be of oval character, and the perturbations of the stator are considered triangular. By numerical and analytical methods it is concluded for which generator parameters harmful conditions, such as complicated whirling motion and high amplitudes, will occur. During maintenance of hydro power generators the shapes of the rotor and stator are frequently measured. The results from this paper can be used to evaluate such measurements and to explain the existence of complex whirling motion.

Lundström, Niklas L. P.; Aidanpää, Jan-Olov

2011-02-01

71

Stator winding resistance estimation for temperature monitoring of induction motor under unbalance supplying by DC injection method  

Microsoft Academic Search

In this paper, stator-winding resistance has been estimated for temperature monitoring of induction motor under unbalance supplying condition. For this reason, the resistance of stator winding is estimated under balance and unbalanced condition by injecting a DC signal to AC voltage. In this study, the stator temperature is measured by construction of a temperature measurement system using sensor-installing method. Each

M. Sabaghi; H. Feshki Farahani; H. R. Hafezi; P. Kiani; A. R. Jalilian

2007-01-01

72

Finite-element analysis of the rotor\\/stator contact in a ring-type ultrasonic motor  

Microsoft Academic Search

A way to understand mechanical characteristics of an ultrasonic motor is presented. First, the vibration mode of a stator is calculated using a finite-element method (FEM) code. The path of the elliptic motion of the stator's teeth is obtained. The computed vibration mode at the surface of the stator is compared with that measured by an electrooptical displacement transducer. Next,

Takashi Maeno; Takayuki Tsukimoto; Akira Miyake

1992-01-01

73

The effect of tangential elasticity of the contact layer between stator and rotor in travelling wave ultrasonic motors  

Microsoft Academic Search

In travelling wave ultrasonic motors the elliptical motion of material points of the stator drives the rotor due to frictional mechanisms. The motor characteristic strongly depends on the mechanical properties of the components stator, rotor and contact layer. In order to predict the motor behaviour, a model for the contact between stator and rotor has been developed. The goal of

Heiner Storck; Jörg Wallaschek

2003-01-01

74

Interactions of a propeller with a stator-induced circumferentially varying flow  

NASA Astrophysics Data System (ADS)

The interactions of a circumferentially varying stator cascade and a downstream fixed pitch propeller were investigated experimentally. The global performance of the components and the coupled system were systematically investigated through force and moment measurements on the propulsor model in a water tunnel. In addition, the wake of the cyclic stator cascade with and without the propeller was investigated downstream from a propulsor model using the Stereoscopic PIV technique. A cyclic distribution of the stators' deflections resulted in non-axisymmetric distributions of the flow field downstream of the stator array. The stator distribution alone produced a significant side force that increased linearly with stator pitch amplitude. When a propeller was incorporated downstream from the cyclic cascade, the side force from the stator cascade was reduced, but a small normal force and pitching moment were created. The generation of these secondary forces and moments can be related to the redistribution of the tangential flow from the cyclic cascade into the axial direction by the retreating and advancing blade states of the fixed pitch propeller.

Farnsworth, John; Amitay, Michael; Beal, David; Huyer, Stephen A.

2012-02-01

75

Electrostatic interactions between rotor and stator in the bacterial flagellar motor.  

PubMed

Bacterial flagellar motors rotate, obtaining power from the membrane gradient of protons or, in some species, sodium ions. Torque generation in the flagellar motor must involve interactions between components of the rotor and components of the stator. Sites of interaction between the rotor and stator have not been identified. Mutational studies of the rotor protein FliG and the stator protein MotA showed that both proteins contain charged residues essential for motor rotation. This suggests that functionally important electrostatic interactions might occur between the rotor and stator. To test this proposal, we examined double mutants with charged-residue substitutions in both the rotor protein FliG and the stator protein MotA. Several combinations of FliG mutations with MotA mutations exhibited strong synergism, whereas others showed strong suppression, in a pattern that indicates that the functionally important charged residues of FliG interact with those of MotA. These results identify a functionally important site of interaction between the rotor and stator and suggest a hypothesis for electrostatic interactions at the rotor-stator interface. PMID:9600984

Zhou, J; Lloyd, S A; Blair, D F

1998-05-26

76

PSP Measurement of Stator Vane Surface Pressures in a High Speed Fan.  

National Technical Information Service (NTIS)

This paper presents measurements of static pressures on the stator vane suction side of a high-speed single stage fan using the technique of pressure sensitive paint (PSP). The paper illustrates development in application of the relatively new experimenta...

J. Lepicovsky

1998-01-01

77

Specific features relating to the motion of a rotor with rubbing against the stator  

NASA Astrophysics Data System (ADS)

Specific features relating to the motion of a rotor with rubbing against the stator and the rolling of a rotor over the stator are considered. Conditions under which rolling of the rotor over the stator occurs and the kinematic and force characteristics of this phenomenon are investigated. Simple analytical solutions are obtained for a model assuming that an absolutely rigid rotor and an absolutely rigid stator come in absolutely inelastic contact with each other, which allow one to get a clear idea about the roll-over phenomenon. An attempt is made on the basis of the proposed model to understand some striking features of the accident that occurred in the 300 MW power unit at the Kashira district power station in 2002.

Kostyuk, A. G.; Shatokhin, V. F.; Volokhovskaya, O. A.

2013-09-01

78

A stator and rotor resistance estimation technique for conductor temperature monitoring  

Microsoft Academic Search

A stator and rotor resistance (Rs,Rr) estimation technique for the purpose of stator winding and rotor conductor temperature (Ts,Tr) monitoring is presented in this paper. Since resistance is a direct indicator of temperature, resistance-based temperature estimation provides many advantages over conventional thermal model based methods. The proposed estimation scheme is a two-step procedure based on the voltage, current, and speed

Sang-Bin Lee; Thomas G. Habetler; Ronald G. Harley; David J. Gritter

2000-01-01

79

Bearing current prevention of converter-fed AC machines with a conductive shielding in stator slots  

Microsoft Academic Search

The paper analyses a shielding method against circulating-type bearing currents in converter-fed AC machines. These currents are induced by the high-frequency flux components that are generated by the common-mode current penetrating the stator core. A conductive shield is placed in the stator slots between the winding and the core, providing a low-impedance path for high-frequency common-mode currents. The shielding effectiveness

Jorma Luomi

2003-01-01

80

Ac hysteresis loop measurement of stator-tooth in induction motor  

SciTech Connect

The properties of ac hysteresis loop of a stator tooth in a 5 hp induction motor was measured and analyzed. The load increase on the motor decreased magnetic induction, however increase the minor hysteresis loops in the high induction region. This effect caused increase in the core loss. Depending on condition of the motor, the core loss of the stator tooth can be 50% greater than the core loss under sinusoidal magnetic induction waveform.

Son, D.

1999-09-01

81

A novel stand-alone dual stator-winding induction generator with static excitation regulation  

Microsoft Academic Search

On the basis of the new idea of electric power integration, a novel stand-alone dual stator-winding induction generator (DWIG) system is built. In this generator, there are two sets of windings to be embedded in the stator slots. One, referred to as the 12-phase power winding, supplies power to the dc load via a 12-phase bridge rectifier, and the other,

Dong Wang; Weiming Ma; Fei Xiao; Botao Zhang; Dezhi Liu; An Hu

2005-01-01

82

An Axial Flux Permanent Magnet Machine with charged polymer stator core  

Microsoft Academic Search

This paper proposes an Axial Flux Permanent Mag- net Machine with cast-injection charged-polymer stator core. The motor is for a washing machine direct-drive. The paper presents the design procedure, the stator production process and the experimental characterization of the prototype. I. INTRODUCTION Axial-flux machines present three-dimensional flux paths, therefore manufacture of laminated cores isn't easy. Composite materials may overcome this

Roberto Di Stefano; Fabrizio Marignetti

2011-01-01

83

Analysis of in-service aged stator bars  

SciTech Connect

Stator bars subjected to operating stresses for 7 and 22 year periods were retrieved from a hydro-generator to undergo short term electrical diagnostic tests in order to determine whether any significant aging of the insulation had taken place. The ac breakdown voltage (U{sub bk}), partial discharge inception voltage (PDIV), the maximum charge ({Delta}Q{sub m}) and total apparent charge (TAC) transfer of the partial discharges, tan{delta} and tan{delta} tip-up comprised the measured quantities statistically evaluated in the diagnostic test procedure. The ac breakdown voltage, PDIV and {Delta}Q{sub m} were found to exhibit a systematic trend with in-service time, thereby suggesting the occurrence of aging effects. That is, both the ac breakdown voltage and the PDIV were characterized by a decrease with time in-service, while the {Delta}Q{sub m} value exhibited an increase. However, no definite behavior was evinced by the TAC, tan{delta} and tan{delta} tip-up values. The significance of the diagnostic test results is discussed in terms of Weibull statistics and the partial discharge behavior with time.

Morin, R.; Novak, J.P.; Bartnikas, R. [Institut de Recherche d`Hydro Quebec, Varennes, Quebec (Canada); Ross, R. [Hydro-Quebec, Montreal, Quebec (Canada)

1995-12-01

84

Rotor-stator molecular crystals of fullerenes with cubane.  

PubMed

Cubane (C8H8) and fullerene (C60) are famous cage molecules with shapes of platonic or archimedean solids. Their remarkable chemical and solid-state properties have induced great scientific interest. Both materials form polymorphic crystals of molecules with variable orientational ordering. The idea of intercalating fullerene with cubane was raised several years ago but no attempts at preparation have been reported. Here we show that C60 and similarly C70 form high-symmetry molecular crystals with cubane owing to topological molecular recognition between the convex surface of fullerenes and the concave cubane. Static cubane occupies the octahedral voids of the face-centred-cubic structures and acts as a bearing between the rotating fullerene molecules. The smooth contact of the rotor and stator molecules decreases significantly the temperature of orientational ordering. These materials have great topochemical importance: at elevated temperatures they transform to high-stability covalent derivatives although preserving their crystalline appearance. The size-dependent molecular recognition promises selective formation of related structures with higher fullerenes and/or substituted cubanes. PMID:16142242

Pekker, Sándor; Kováts, Eva; Oszlányi, Gábor; Bényei, Gyula; Klupp, Gyöngyi; Bortel, Gábor; Jalsovszky, István; Jakab, Emma; Borondics, Ferenc; Kamarás, Katalin; Bokor, Mónika; Kriza, György; Tompa, Kálmán; Faigel, Gyula

2005-09-04

85

Unsupervised Neural-Network-Based Algorithm for an On-Line Diagnosis of Three-Phase Induction Motor Stator Fault  

Microsoft Academic Search

In this paper, an automatic algorithm based an unsupervised neural network for an on-line diagnostics of three-phase induction motor stator fault is presented. This algorithm uses the alfa-beta stator currents as input variables. Then, a fully automatic unsupervised method is applied in which a Hebbian-based unsupervised neural network is used to extract the principal components of the stator current data.

J. F. Martins; V. Fernão Pires; A. J. Pires

2007-01-01

86

A stator for a self-running, ultrasonically-levitated sliding stage.  

PubMed

Here we propose a self-running, ultrasonically-levitated sliding stage and investigate the levitation and propulsion characteristics of its stator. The stator consists of two aluminum beams and four PZT plates, which have two-paired bimorph configurations. A flexural standing wave was generated along the beam by applying an input voltage to the PZTs, and the stator could be levitated from a flat substrate by the acoustic radiation force generated by its own vibrating beam. The size of the stator was optimized using finite-element analysis (FEA) to maximize the vibration displacement amplitude of the beam. The flexural vibration modes at 24.3 and 102 kHz were the most prominent vibration modes having large displacement amplitudes. The stator was levitated at 23.2 and 96.1 kHz, which are close to the frequencies predicted by the FEA results. A standing wave was observed along the beam. The experimental and the simulated results showed good agreement. The levitation distance h was measured by varying the vibration displacement amplitude of the beam u, and was found to be proportional to u. When a traveling wave was excited along the beam by controlling the temporal phase difference of the two transducers, the stator could be made to hover and to move in the opposite direction to the traveling wave. The stator moved in the positive direction when the phase difference was in the ranges 0 degrees to 200 degrees and 310 degrees to 360 degrees, and in the negative direction when the phase difference was between 220 degrees and 260 degrees. PMID:18051168

Koyama, Daisuke; Nakamura, Kentaro; Ueha, Sadayuki

2007-11-01

87

Reduction of Unsteady Stator-Rotor Interaction Using Trailing Edge Blowing  

NASA Astrophysics Data System (ADS)

An aeroacoustic investigation was performed to assess the effects of adding mass flow at the trailing edges of stators upstream of an aircraft engine simulator. By using trailing edge blowing to minimize the shed wakes of the stators, the flow into the rotor was made more uniform, hence reducing the unsteady stator-rotor interaction. In these experiments, a reduced number of stators (four) was used in a 1/14 scale model inlet which was coupled to a 4.1in (10.4 cm) turbofan engine simulator. Steady state measurements of the aerodynamic flow field and acoustic far field were made in order to evaluate the aeroacoustic performance at three simulator speeds: 30k, 50k, and 70kr.p.m. The lowest test speed (30k r.p.m.) showed a noise reduction as large as 8.9dB in the blade passing tone. At 50k and 70kr.p.m., the reduction in blade passing tone was 5.5 and 2.6dB respectively. In addition, trailing edge blowing reduced the overall sound pressure level in every case. Aerodynamic measurements showed that fan face distortion was significantly reduced due to trailing edge blowing. The addition of trailing edge blowing from the four upstream stators did not change the operating point of the fan, and the mass flow added by the blowing was less than 1% of the fan mass flow rate. The results of these experiments clearly demonstrate that blowing from the trailing edges of the stators is effective in reducing unsteady stator-rotor interaction and the subsequent forward radiated noise.

Leitch, Thomas A.; Saunders, C. A.; Ng, W. F.

2000-08-01

88

Modal decomposition for the analysis of the rotor-stator interactions in multistage compressors  

NASA Astrophysics Data System (ADS)

A modal analysis method of the rotor-stator interactions in multistage compressors has been developed by LMFA. This method, based on a double modal decomposition of the flow over space and time, has been applied to numerical and experimental results of the high-speed 3½-stage compressor CREATE based at LMFA, Lyon-France. It reveals the presence of a very strong rotor-stator interaction which completely drives the flow at casing behind all the rotors. This modal analysis method applied to an unsteady RANS simulation permits to calculate the energy of the rotor-stator interactions and to plot energetic meridian maps to explain experimental results and to analyze the interaction in the whole machine.

Courtiade, N.; Ottavy, X.; Gourdain, N.

2012-06-01

89

Study on the effects of end-bend cantilevered stator in a 2-stage axial compressor  

NASA Astrophysics Data System (ADS)

Leading edge recambering is applied to the cantilevered stator vanes in a 2-stage compressor in this paper. Different curving effects are produced when the end-bend stator vanes are stacked in different ways. Stacking on the leading edge induces a positive curving effect near the casing. When it is stacked on the centre of gravity, a negative curving effect takes place. The numerical investigation shows that the flow field is redistributed when the end-bend stators with leading edge stacking are applied. The variations in the stage matching for the mainstream and near the hub have an impact on the performance of the 2-stage compressor. The isentropic efficiency and the total pressure ratio of the compressor are increased near the design condition. The compressor total pressure ratio is decreased near choke and near stall. The maximum flow rate is reduced and the stall margin is decreased.

Wang, Songtao; Du, Xin; Wang, Zhongqi

2009-06-01

90

An online identification method for both stator-and rotor resistances of induction motors without rotational transducers  

Microsoft Academic Search

This paper describes an effective online method for identifying both stator and rotor resistances, which is useful in robust speed control of induction motors without rotational transducers. The identification method for stator resistance is derived from the steady-state equations of induction motor dynamics. On the other hand, the identification method for rotor resistance is based on the linearly perturbed equations

In-Joong Ha; Sang-Hoon Lee

2000-01-01

91

Cause and analysis of stator and rotor failures in three-phase squirrel-cage induction motors  

Microsoft Academic Search

The squirrel cage induction motor has limitations, which, if exceeded, will result in premature failure of the stator or rotor. The authors identify the various causes of stator and rotor failures. A specific methodology is proposed to facilitate an accurate analysis of these failures. Failures of the bearings and lubrication systems are excluded

Austin H. Bonnett; George C. Soukup

1992-01-01

92

Stator winding fault diagnosis in three-phase synchronous and asynchronous motors, by the extended Park's vector approach  

Microsoft Academic Search

This paper describes the use of the extended Park's vector approach (EPVA) for diagnosing the occurrence of stator winding faults in operating three-phase synchronous and asynchronous motors. The major theoretical principles related with the EPVA are presented and it is shown how stator winding faults can be effectively diagnosed by the use of this noninvasive approach. Experimental results, obtained in

S. M. A. Cruz; A. J. Marques Cardoso

2000-01-01

93

Stator winding fault diagnosis in three-phase synchronous and asynchronous motors, by the extended Park's vector approach  

Microsoft Academic Search

This paper describes the use of the extended Park's vector approach (EPVA) for diagnosing the occurrence of stator winding faults in operating three-phase synchronous and asynchronous motors. The major theoretical principles related with the EPVA are presented and it is shown how stator winding faults can be effectively diagnosed by the use of this noninvasive approach. Experimental results, obtained in

Sérgio M. A. Cruz; A. J. Marques Cardoso

2001-01-01

94

Calculation of 3D nonlinear stator temperature field after insulation aging and shelling for large synchronous generator based on FEM  

Microsoft Academic Search

A salient pole synchronous generator is taken for an example to be calculated in this paper. The 3D isoparametric finite element method and Newton-Raphson method are applied to compute the 3D thermal field while the flow field in stator ventilating grooves is a nonlinear field. At the same time, numerical simulation method is used to analyze the stator thermal field

Zhou Feng; Li Weili; Hou Yunpeng; Luo Yingli

2002-01-01

95

Effect of toothless stator design on the dynamic performance characteristics of high speed permanent magnet generator-load systems  

Microsoft Academic Search

The results of a study on the effect of toothless stator design on the dynamic performance characteristics of high speed permanent magnet generator-load systems are presented. This study is based on the use of magnetic field solutions and state space models which account for saturation due to magnetic material nonlinearities and space harmonics due to machine geometry. Two particular stator

R. Vyas; A. A. Arkadan

1994-01-01

96

Efficiency analysis of induction motors for ammonia compressors considering stray load losses caused by stator and rotor slot ripple  

Microsoft Academic Search

In this paper, we investigate the losses and the efficiency of induction motors for ammonia compressors, which have a metallic can inserted in the air-gap to prevent ammonia from entering the stator and damaging the primary windings. The finite element analysis is applied to calculate the torque, primary and secondary copper losses, stator and rotor core losses and eddy current

Katsumi. Yamazaki

2001-01-01

97

Vortical gust boundary condition for realistic rotor wake/stator interaction noise prediction using computational aeroacoustics  

NASA Astrophysics Data System (ADS)

In this work, the NASA Glenn Research Center Broadband Aeroacoustic Stator Simulation (BASS) code is extended for use in the prediction of noise produced by realistic three-dimensional rotor wakes impinging on a downstream stator row. In order to accurately simulate such a flow using a nonlinear time-accurate solver, the inflow and outflow boundary conditions must simultaneously maintain the desired mean flow, allow outgoing vortical, entropic, and acoustic waves to cleanly exit the domain, and accurately impose the desired incoming flow disturbances. This work validates a new method for the acoustics-free imposition of three-dimensional vortical disturbances using benchmark test cases.

Hixon, Ray; Sescu, Adrian; Sawyer, Scott

2011-08-01

98

Economic aspects of minimising the effects of mechanical stress in induction motor stator cores  

NASA Astrophysics Data System (ADS)

The localised flux density distribution and corresponding localised iron loss of stacks of non-oriented, silicon free iron, induction motor stator laminations have been measured together with a finite element analysis of mechanical stress distribution caused by radial clamping. The results show the value of choosing an inner frame diameter large enough to avoid high compression in terms of an annual saving in the cost of core loss or a reduction in the stator conductor cross sectional area. Now at Dept. of Electrical Engineering, Shalid Shamsi-our Institute, Tehran.

Moses, A. J.; Rahmatizadeh, H.

1992-07-01

99

Flow and coupled heat transfer in the cavity between the rotor and stator  

NASA Astrophysics Data System (ADS)

The turbulent flow and coupled heat transfer in the cavity between the rotor and stator is numerically simulated. Reynolds-averaged Navier-Stokes equations closed with equations of the k-? turbulence model are used to calculate the viscous compressible gas flow characteristics and heat transfer; the unsteady heat conduction equation is used to calculate the temperature field in the metal. The influence of the mass flow rate of the coolant on the flow structure and efficiency of cooling of the rotor and stator walls is studied. The calculated results are compared with experimental data.

Volkov, K. N.

2011-05-01

100

Driving the Coiled Stator Ultrasonic Motor Using Traveling Wave Generated by Superimposing Two Standing Waves  

NASA Astrophysics Data System (ADS)

In this paper, we describe experimental results of driving a coiled stator ultrasonic motor (CS-USM) using two transducers simultaneously. When the transducers are excited with a certain phase difference, the rotation direction is reversed. The CS-USM is a traveling-wave-type ultrasonic motor that uses a stator in a form of a helical coil. Owing to its simple structure, the motor can be made much smaller than conventional ultrasonic motors. For its practical use, the motor must be driven by transducers placed close to the driving section, and the direction of the rotation must be controlled.

Tanabe, Masayuki; Xie, Shangping; Tagawa, Norio; Moriya, Tadashi

2008-05-01

101

Digital signal processing control of induction machine`s torque and stator flux utilizing the direct stator flux field orientation method  

SciTech Connect

This paper presents a review of the Direct Stator Flux Field Orientation control method. This method can be used to control an induction motor`s torque and flux directly and is the application of interest for this thesis. This control method is implemented without the traditional feedback loops and associated hardware. Predictions are made, by mathematical calculations, of the stator voltage vector. The voltage vector is determined twice a switching period. The switching period is fixed throughout the analysis. The three phase inverter duty cycle necessary to control the torque and flux of the induction machine is determined by the voltage space vector Pulse Width Modulation (PWM) technique. Transient performance of either the flux or torque requires an alternate modulation scheme which is also addressed in this thesis. A block diagram of this closed loop system is provided. 22 figs., 7 tabs.

Seiz, J.B.

1997-04-01

102

Novel frequency-domain-based technique to detect stator interturn faults in induction machines using stator-induced voltages after switch-off  

Microsoft Academic Search

Traditionally, for medium- and high-voltage motors and generators, condition-based monitoring of stator faults is performed by measuring partial discharge activities. For low-voltage machines, negative-sequence impedance or currents are measured for the same. Such diagnostic schemes should be carefully implemented as supply voltage unbalance, manufacturing-related asymmetry, etc., also produce negative-sequence voltages. A few approaches based on motor current signature analysis have

Subhasis Nandi; Hamid A. Toliyat

2002-01-01

103

INFLUENCE OF STATOR AND ROTOR RESISTANCE VARIATIONS ON FLUX AND SPEED ESTIMATION  

Microsoft Academic Search

The accuracy of speed estimation algorithms for induction machine depends on the accuracy of the machine parameters used in the algorithm. Motor parameters especially the stator and rotor resistances vary with temperature change during motor operation. This paper explores the influence of parameter variations on estimated speed and estimated rotor flux analytically and by simulation of the algorithm at steady

S. Sathiakumar

104

Stator and rotor resistance observers for induction motor drive using fuzzy logic and artificial neural networks  

Microsoft Academic Search

This paper presents a new method of on-line estimation for the stator and rotor resistances of the induction motor in the indirect vector controlled drive, using fuzzy logic and artificial neural networks. The back propagation algorithm is used for the training of the neural networks for rotor resistance identification. The error between the desired state variable of an induction motor

Baburaj Karanayil; Muhammed Fazlur Rahman; Colin Grantham

2003-01-01

105

Stator and rotor resistance observers for induction motor drive using fuzzy logic and artificial neural networks  

Microsoft Academic Search

This paper presents a new observer for the rotor resistance of an indirect vector controlled induction motor drive using artificial neural networks supplemented by a fuzzy logic based stator resistance observer. The error between the rotor flux linkages based on a neural network model and a voltage model is back propagated to adjust the weights of the neural network model

Baburaj Karanayil; Muhammed Fazlur Rahman; Colin Grantham

2005-01-01

106

High gain observer based on-line rotor and stator resistances estimation for IMs  

Microsoft Academic Search

One of the main challenging issues in induction motor drives is the lack of knowledge about the actual values of some critical parameters, such as rotor and stator resistances which are subject to large variations during operation. Such problem is difficult to resolve due to the strong interconnection between states and parameters in the nonlinear motor model, besides the unavailability

S. H. Sai?d; F. Mimouni; F. M'Sahli; M. Farza

2010-01-01

107

High gain observer based on-line rotor and stator resistances estimation for IMs  

Microsoft Academic Search

One of the main challenging issues in induction motor drives is the lack of knowledge about the actual values of some critical parameters, such as rotor and stator resistances which are subject to large variations during operation. Such problem is difficult to resolve due to the strong interconnection between states and parameters in the nonlinear motor model, besides the unavailability

S. Hadj Saïd; M. F. Mimouni; F. M’Sahli; M. Farza

2011-01-01

108

Novel process for the fabrication of top-drive double stator micromotor on glass  

NASA Astrophysics Data System (ADS)

A top-drive variable capacitance (VC) electrostatic rotational micromotor with double stator was fabricated combining bulk silicon machining with etch stop on junction to anodic bonding of silicon to glass. The novel process overcomes the drawbacks found in the fabrication of top- drive devices by use of usual surface micromachining of polysilicon LPCVD layers.

Ziad, Hocine; Spirkovitch, Serge; Marty, Jeannine; Baillieu, Francois; Rigo, Serge; Milne, Neil

1994-02-01

109

A piezoelectric linear ultrasonic motor with the structure of a circular cylindrical stator and slider  

NASA Astrophysics Data System (ADS)

A piezoelectric linear ultrasonic motor is proposed, with a cylindrical stator and slider structure. The length and diameter of the motor are about 10 and 1.5 mm, respectively. The stator consists of two piezoelectric ceramic (PZT) tubes connected by a thin film metallic glass (TFMG) pipe. The stator is designed based on theoretical analyses and finite element method (FEM) simulation. The traveling wave propagation is obtained in the FEM simulation under the proper geometrical sizes, suitable boundary conditions and driving voltage signals. The trajectories of particles on the TFMG pipe are elliptical motion. In the experiment, a 25 µm thick TFMG pipe is fabricated using the rotating magnetron sputtering technique and the vibration characteristics of the stator are measured by a laser Doppler vibrometer (LDV) system. Bidirectional motion of the slider is observed around 600 kHz, the maximum velocity is near to 40 mm s - 1 at 50 Vp-p for the loose slider and the maximum output force is 6 mN at 70 Vp-p for the tight slider.

Sun, Dongming; Wang, Sheng; Sakurai, Junpei; Choi, Kee-Bong; Shimokohbe, Akira; Hata, Seiichi

2010-04-01

110

A `Center-Wobbling' Ultrasonic Rotary Motor Using a Metal Tube-Piezoelectric Plate Composite Stator  

Microsoft Academic Search

This paper demonstrates a new type of compact ultrasonic motor that operates using a wobbling mode of motion. The motor was driven by a piezoelectric composite stator that consisted of a hollow metal cylinder whose outside surface was flattened on two sides at 90° to each other, upon which two rectangular piezoelectric plates were bonded. A wobbling motion was generated

Shuxiang Dong; S. Cagatay; K. Uchino; D. Viehland

2002-01-01

111

Condition assessment study on stator bars, after 40 years of operation  

Microsoft Academic Search

The knowledge of the condition of a stator bar insulation after a long period of operation is a key point for enabling a reliable operation and for the decision on an investment for a rewind. The Insulation Competence Center (ICC) of Alstom had the opportunity to investigate the condition of operation-aged Micadurreg bars, which originate from the beginning of the

C. Wendel; C.-E. Stephan; C. Picech; G. Csaba

2006-01-01

112

Ultra-high speed permanent magnet axial gap alternator with multiple stators  

DOEpatents

An ultra-high speed, axial gap alternator that can provide an output to a plurality of loads, the alternator providing magnetic isolation such that operating conditions in one load will not affect operating conditions of another load. This improved alternator uses a rotor member disposed between a pair of stator members, with magnets disposed in each of the rotor member surfaces facing the stator members. The magnets in one surface of the rotor member, which alternate in polarity, are isolated from the magnets in the other surface of the rotor member by a disk of magnetic material disposed between the two sets of magents. In the preferred embodiment, this disk of magnetic material is laminated between two layers of non-magnetic material that support the magnets, and the magnetic material has a peripheral rim that extends to both surfaces of the rotor member to enhance the structural integrity. The stator members are substantially conventional in construction in that equally-spaced and radially-oriented slots are provided, and winding members are laid in these slots. A unit with multiple rotor members and stator members is also described.

Hawsey, Robert A. (Oak Ridge, TN); Bailey, J. Milton (Knoxville, TN)

1991-01-01

113

Position sensorless synchronous reluctance motor drive using the stator phase voltage third harmonic  

Microsoft Academic Search

A direct field orientation controller for synchronous reluctance motors based on determination of the spiral position of the air gap flux from the third harmonic component of the stator phase voltages is presented. The control utilizes the spatial saturation harmonic components rotating at synchronous frequency that are generated in the air gap flux when the machine operates in a saturated

Liviu Kreindler; Antonio Testa; T.A. Lipo

1993-01-01

114

Evaluation of experimental permanent-magnet brushless motor utilizing new magnetic material for stator core teeth  

Microsoft Academic Search

We prepared motors with experimental cores using a soft magnetic composite and an amorphous metal and evaluated their performance. We measured the magnetic and motor characteristics, such as iron loss, when the new materials were used in the stator core teeth. The amorphous metal was found to have very high permeability and low iron loss, whereas the soft magnetic composite

Y. Enomoto; M. Ito; H. Koharagi; R. Masaki; S. Ohiwa; C. Ishihara; M. Mita

2005-01-01

115

Ultra-high speed permanent magnet axial gap alternator with multiple stators  

DOEpatents

An ultra-high speed, axial gap alternator that can provide an output to a plurality of loads, the alternator providing magnetic isolation such that operating conditions in one load will not affect operating conditions of another load. This improved alternator uses a rotor member disposed between a pair of stator members, with magnets disposed in each of the rotor member surfaces facing the stator members. The magnets in one surface of the rotor member, which alternate in polarity, are isolated from the magnets in the other surface of the rotor member by a disk of magnetic material disposed between the two sets of magnets. In the preferred embodiment, this disk of magnetic material is laminated between two layers of non-magnetic material that support the magnets, and the magnetic material has a peripheral rim that extends to both surfaces of the rotor member to enhance the structural integrity. The stator members are substantially conventional in construction in that equally-spaced and radially-oriented slots are provided, and winding members are laid in these slots. A unit with multiple rotor members and stator members is also described. 6 figs.

Hawsey, R.A.; Bailey, J.M.

1990-03-28

116

Two-Stage Fan. 4: Performance Data for Stator Setting Angle Optimization.  

National Technical Information Service (NTIS)

Stator setting angle optimization tests were conducted on a two-stage fan to improve efficiency at overspeed, stall margin at design speed, and both efficiency and stall margin at partspeed. The fan has a design pressure ratio of 2.8, a flow rate of 184.2...

G. D. Burger M. J. Keenan

1975-01-01

117

Synchronous running of voltage-fed miniature single-stator permanent magnet motors  

Microsoft Academic Search

A mathematical model is established for a single-stator permanent magnet synchronous motor when voltage-fed. Non-dimensional parameters governing the behaviour of the rotor are identified and conditions on them determined under which the motor goes into synchronous running both when loaded and when unloaded. The maximum torque which the motor can develop and when this can occur are investigated.

W. D. Collins

2005-01-01

118

Analytical approach of the stator current frequency harmonics computation for detection of induction machine rotor faults  

Microsoft Academic Search

The aim of this paper is to analyze theoretically and experimentally the stator current of a three-phase squirrel cage induction machine in order to show how it is influenced by rotor faults. The approach used for this study analyzes the modification introduced by n broken rotor bars in the rotor cage magnetomotive force (MMF) and then, estimates the resulting frequency

H. Henao; G. A. Capolino; H. Razik

2003-01-01

119

Rotor-Stator-Interaction of a Radial Centrifugal Pump Stage with Minimum Stage Diameter  

Microsoft Academic Search

For radial multistage pumps with stationary vaned diffusers the diameter of the pump casing is much larger than the diameter of the impeller. In the case of submersible pumps, where just a limited space for installing the pump is available, smaller stator diameters need to be realized resulting in a loss in efficiency. Improving the design of these pumps and

D.-H. Hellmann

120

Étude des structures spirales à la périphérie d'une cavité rotor–stator aspirée  

Microsoft Academic Search

The influence of suction on the spirals pattern that appear on the periphery of an aspirated opened rotor–stator cavity is studied by means of tomography. A radial gap, located between the rotating disk and the fixed cylindrical wall allow the suction of an outer flux made up of a jet of fresh air and a high contrasted smoke thin sheet

David Rémy; Georges Gauthier; Daniel Buisine

2004-01-01

121

Heat transfer measurements in an opened rotor-stator system air-gap  

Microsoft Academic Search

This article presents an experimental study of the heat transfers in a discoidal rotor-stator system air-gap. Measurements are performed over the rotor, using an experimental technique based on infrared thermography, in order to determine the surface temperatures. Using a thermal balance, the local convective heat transfer coefficient is identified. The influences of the rotational Reynolds number Re and the dimensionless

Julien Pelle; Souad Harmand

2007-01-01

122

Heat transfer measurements in an opened rotor–stator system air-gap  

Microsoft Academic Search

This article presents an experimental study of the heat transfers in a discoidal rotor–stator system air-gap. Measurements are performed over the rotor, using an experimental technique based on infrared thermography, in order to determine the surface temperatures. Using a thermal balance, the local convective heat transfer coefficient is identified. The influences of the rotational Reynolds number Re and the dimensionless

Julien Pellé; Souad Harmand

2007-01-01

123

Stator Conductor and Bore Seal Study for the Advanced High-Power Generator Program.  

National Technical Information Service (NTIS)

This report describes the results of a preliminary study to simplify the 36-strand, liquid-cooled stator conductor for the advanced 5-Mw, high-power generator. A specially configured four-strand conductor significantly simplifies the fabrication process w...

A. Druzsba

1986-01-01

124

Experimental Investigation of Rotor Wake/Stator Interaction Noise Generation by Acoustic Mode Measurements.  

National Technical Information Service (NTIS)

An experimental investigation was carried out in a low speed wind tunnel to generate test results for a verification and validation of a theory for fan noise generation due to rotor wake/stator interaction. Reported is a follow-up experiment including det...

T. Zandbergen

1989-01-01

125

The global responses characteristics of a rotor/stator rubbing system with dry friction effects  

NASA Astrophysics Data System (ADS)

Rotor/stator rubbing systems may undertake a number of quite different responses. Recent experiments on rotor/stator rubbing have revealed that two or three different responses may coexist. In this paper the global response characteristics of a general rotor/stator rubbing system, which takes into account the dominant factors in the process of rotor/stator rubbing, especially, the dry friction effect that is mostly neglected in the previous works and is the main factor for the self-excited dry friction backward whirl, are studied. The different solutions of the piecewise nonlinear system are derived and their stability are analyzed to get the existence boundaries of the different responses. An overall picture of the global response characteristics of this model is then obtained by drawing the existence boundaries in a same parameter space. The present results provide good understanding on the coexistence of different rubbing responses observed in tests. Moreover, deeper insight into the types of coexistence of different rubbing responses and their relationship with the system parameters is gained.

Shang, Zhiyong; Jiang, Jun; Hong, Ling

2011-05-01

126

Unsteady flows in a single-stage transonic axial-flow fan stator row  

NASA Astrophysics Data System (ADS)

Detailed measurements of the unsteady velocity field within the stator flow of a transonic axial-flow fan were acquired using a laser anemometer. They were obtained on axisymmetric surfaces located at 10 and 50 percent span from the shroud, with the fan operating at maximum efficiency at design speed. The ensemble-average and variance of the measured velocities are used to identify rotor-wake-generated (deterministic) unsteadiness and turbulence, respectively. Correlations of both deterministic and turbulent velocity fluctuations provide information on the characteristics of unsteady interactions within the stator row. These correlations are derived from the Navier-Stokes equation in a manner similar to deriving the Reynolds stress terms, whereby various averaging operators are used to average the aperiodic, deterministic, and turbulent velocity fluctuations known to be present in multistage turbomachines. The correlations of deterministic and turbulent velocity fluctuations throughout the axial fan stator row are presented. In particular, amplification and attenuation of both types of unsteadiness are shown to occur within the stator blade passage.

Hathaway, Michael Dale

127

Stability Analysis of Speed and Stator Resistance Estimators for Sensorless Induction Motor Drives  

Microsoft Academic Search

This paper presents an analysis by which the stability of a multiple-input-multiple-output system of simultaneous speed and stator resistance estimators for sensorless induction motor drives can be successfully predicted. The instability problem of an adaptive flux observer (AFO) is deeply investigated. In order to achieve stability over a wide range of operation, a design of the observer feedback gain is

Mohamed S. Zaky

2012-01-01

128

Hybrid stator-pole switched reluctance motor to improve radial force for bearingless application  

Microsoft Academic Search

A novel hybrid stator-pole switched reluctance motor (HSPSRM) to improve radial force for bearingless application is presented in this paper. The proposed motor can generate a constant suspending force independent of rotor position only using small current excitation. And torque control can be naturally decoupled form suspending force control. Measured data and the results of numerical analysis are given to

Huijun Wang; Dong-Hee Lee; Tae-Hub Park; Jin-Woo Ahn

2011-01-01

129

Novel miniature motors with lateral stator for a wide torque and speed range  

Microsoft Academic Search

For various drilling applications where the space in the tool head is limited, two motor topologies with the stator outsourced from the head are proposed, allowing for compact design and direct drive. In order to meet the high torque requirements at low speed and operate at high speed up to 200 000 rpm a finite element analysis (FEA) is carried

A. Tu?ysu?z; A. Looser; J. W. Kolar; C. Zwyssig

2010-01-01

130

An Online Adaptive Stator Winding Temperature Estimator Based on a Hybrid Thermal Model for Induction Machines  

Microsoft Academic Search

Conventional thermal models with a single thermal capacitor and a single thermal resistor are incapable of giving an accurate stator winding temperature estimate tailored to the specific motor's cooling capability. A hybrid thermal model is presented in this paper to account for the disparities in thermal operating conditions for different motors of the same rating, and of the same totally

Zhi Gao; Thomas G. Habetler; Ronald G. Harley

2005-01-01

131

Induction-motor stator and rotor winding temperature estimation using signal injection method  

Microsoft Academic Search

A new method to estimate the induction-motor stator and rotor resistance (Rs and Rr) and temperature (Ts and Tr) was proposed in this paper. Two signals with proper frequencies that yield high sensitivities of the terminal measurement to Rs and Rr at a given rotor speed are injected to the induction machine to estimate Rs and R r. The estimated

Ying Wu; Hongwei Gao

2006-01-01

132

Induction motor current signature analysis to diagnostics, of stator short circuits  

Microsoft Academic Search

The steady-state behaviour of an induction machine with a symmetric rotor cage and a faulty asymmetric stator is analyzed. The asymmetric machine is modeled by means of the space vector approach. The winding asymmetry is taken into account by considering each conductor of every single slot separately. Harmonic components of the permeance produced by the rotor slots are taken into

G. Gentile; S. Meo; A. Ometto

2003-01-01

133

Optimised Segmental Rotor Switched Reluctance Machines with a greater number of rotor segments than stator slots  

Microsoft Academic Search

Segmental Rotor Switched Reluctance Machines have been demonstrated to produce significantly more torque than Conventional Switched Reluctance Machines because each coil is able to link more magnetic flux. In previous work the range of topologies studied has been relatively restricted; there has been no consideration of the range of stator tooth and rotor segment number options and the designs have

J. D. Widmer; B. C. Mecrow

2011-01-01

134

Stator Current and Motor Efficiency as Indicators for Different Types of Bearing Faults in Induction Motors  

Microsoft Academic Search

This paper proposes a new approach to use stator current and efficiency of induction motors as indicators of rolling-bearing faults. After a presentation of the state of the art about condition monitoring of vibration and motor current for the diagnostics of bearings, this paper illustrates the experimental results on four different types of bearing defects: crack in the outer race,

Lucia Frosini; Ezio Bassi

2010-01-01

135

Detection of Induction Motor Faults: A Comparison of Stator Current, Vibration and Acoustic Methods  

Microsoft Academic Search

In this paper we present the comparison results of induction motor fault detection using stator current, vibration, and acoustic methods. A broken rotor bar fault and a combination of bearing faults (inner race, outer race, and rolling element faults) were induced into variable speed three-phase induction motors. Both healthy and faulty signatures were acquired under different speed and load conditions.

WEIDONG LI; CHRIS K. MECHEFSKE

2006-01-01

136

Locating of leaks in water-cooled generator stator bars using perfluorocarbon tracers  

Microsoft Academic Search

Water cooled stator bars in power plant generators often fail during the maintenance cycle due to water leakage. After the hydrogen pressure in the generator shell has been released water can leak through cracks in the copper and through the insulation. Leaking bars, but not the leaks themselves, are detected with so-called hi-pot'' (high potential) tests where direct electrical current

W. M. Loss; R. N. Dietz

1991-01-01

137

Locating of leaks in water-cooled generator stator bars using perfluorocarbon tracers  

Microsoft Academic Search

Water cooled stator bars in power plant generators often fail during the maintenance cycle due to water leakage. After the hydrogen pressure in the generator shell has been released water can leak through cracks in the copper and through the insulation. Leaking bars, but not the leaks themselves, are detected with so-called ``hi-pot`` (high potential) tests where direct electrical current

W. M. Loss; R. N. Dietz

1991-01-01

138

Stator Harmonic Currents in VSI-Fed Synchronous Motors With Multiple Three-Phase Armature Windings  

Microsoft Academic Search

Electric motors equipped with multiple three-phase windings are often used for the advantages they offer in terms of reliability, performance, and inverter power segmentation. When the windings are fed by independent voltage-source inverters (VSIs), circulation harmonic currents can occur in stator phases. If the motor is an induction machine, circulation currents are known to originate form transient imbalances in the

Alberto Tessarolo; Cristina Bassi

2010-01-01

139

Implications for the application of adjustable speed drive electronics to motor stator winding insulation  

Microsoft Academic Search

Medium voltage (2300V to 4160V) motor stator insulation has been designed to withstand voltage surges from circuit breaker operation for many decades. It is probable that the surges created by ASDs will not pose a threat to properly designed and manufactured insulation. However, as ASDs become more popular in the higher voltage ranges, we will have to watch carefully to

J. A. Oliver; G. C. Stone

1995-01-01

140

Research on location and speed detection for high speed maglev train based on long stator  

Microsoft Academic Search

Location and speed detection (LSD) is one of the key technologies of high speed maglev train. The traction system needs precise location and speed information to carry out the traction task of the train normally and reliably. Firstly, several conventional location and speed detection methods are introduced. And then, the method based on the tooth and slots of long stator

Xue Song; Dai Chunhui; Long Zhiqiang

2010-01-01

141

An electric contact method to measure contact state between stator and rotor in a traveling wave ultrasonic motor.  

PubMed

Performances of ultrasonic motor (USM) depend considerably on contact state between stator and rotor. To measure the contact state in a traveling wave ultrasonic motor (TWUSM), a special test method is necessary. This paper develops a new method named electric contact method to measure contact state of stator and rotor in traveling wave type USM. The effects of pre-load and exciting voltage (amplitude) of stator on contact state between stator and rotor are studied with this method. By a simulating tester of friction properties of TWUSM, the variations of stalling torque and no-load speed against the pre-load and the exciting voltage have been measured. The relative contact length that describes the contact characteristic of stator and rotor is proposed. The relation between the properties of TWUSM and the contact state of stator and rotor are presented. Additionally, according to a theoretical contact model of stator and rotor in TWUSM, the contact lengths at given conditions are calculated and compared with the experimental results. PMID:12919692

Qu, Jianjun; Zhou, Tieying

2003-09-01

142

Stator Shape Improvement to Decrease Iron Loss Caused by Shrink Fit Utilizing Physical Properties of Electrical Steel Sheet  

NASA Astrophysics Data System (ADS)

In a motor with a stator which is inserted in a frame by shrink fit, iron loss increases and the increase has become a serious problem. Therefore, the stator shape has been studied to decrease the compression stress. In this paper, a new approach to decrease the loss is proposed, which makes use of physical properties of electrical steel sheet for tension stress, and new stator shape is shown and evaluated by experimental results to decrease the iron loss caused by the shrink fit.

Satoh, Mitsuhiko; Kaneko, Seiichi; Tomita, Mutuwo; Doki, Shinji; Okuma, Shigeru

143

Numerical investigation of influence of rotor/stator interaction on blade boundary layer flow in a low speed compressor  

NASA Astrophysics Data System (ADS)

Numerical method was applied to the unsteady flow simulation at the mid span of a two-stage low speed compressor, and the blade boundary layer flow under rotor/stator interaction was investigated. By the model of wake/boundary layer interaction provided in this paper, the simulated blade frictional force and the boundary layer turbulent kinetic energy, the influence of wake/potential flow interaction on the blade boundary layer flow was analyzed in detail. The results show that under the condition of rotor/stator interaction, the wake is able to induce the stator laminar boundary layer flow to develop into turbulent flow within a certain range of wake interaction. In the stator suction boundary layer, an undisturbed region occurs behind the rotor wake, which extends the laminar flow range, and the wake with high turbulent intensity has the capability to control the boundary layer separation under adverse pressure gradient.

Yao, Hongwei; Yan, Peigang; Han, Wanjin

2011-02-01

144

Analysis of high-voltage generator stator windings sudden three-phase short-circuit and loss of excitation fault  

Microsoft Academic Search

Base on a prototype of the 130 kw\\/5 kv high voltage generator, the system simulation model is set up for the generator stator windings suddenly three-phase short-circuit failure and loss of excitation failures. The dynamic simulation compared with experiment on DJ18-1 synchronous generator, it reaches conclusion that the system simulation model is correct. The current of the high-voltage generator stator

Lv Yan-ling; Ge Bao-jun; Li Cui-cui; Tao Da-jun; Zhang Zhi-qiang

2009-01-01

145

Bureau of Reclamation guidelines regarding high-voltage rotating machine stator winding procurement, installation, and maintenance procedures  

Microsoft Academic Search

The first installations of the new hard epoxy-mica or polyester-mica stator insulation systems in Bureau of Reclamation generators resulted in numerous problems that were not present with the older soft asphalt-mica systems. One of the main attributes of asphalt-mica systems was the tendency for these materials to expand and lock themselves into the stator slots. When the asphalt becomes warm

R. C. Arbour; B. Milano

1989-01-01

146

DSP based stator flux oriented control of doubly-fed induction generator for wind power generation system  

Microsoft Academic Search

This paper presents the control of doubly-fed induction generator (DFIG) for wind energy conversion system by employing stator flux oriented control in the rotor-side converter. The control algorithm is implemented in digital environment using DSP TMS320F2812 processor. A decoupling term has been developed for the cross coupling of d-q stator flux components, and computer simulations as well as laboratory experiments,

B. Chitti Babu; K. B. Mohanty

2012-01-01

147

Exploration of combined adjustment laws about IGV, stator and rotational speed in off-design conditions in an axial compressor  

Microsoft Academic Search

Experimental investigations are performed in a three-stage low-speed axial compressor with variable inlet guide vanes (IGV)\\u000a and adjustable stators. The characteristics of the compressor, especially the efficiency and stall margin, are analyzed in\\u000a design and off-design operation conditions by adjusting stagger angles of IGV and stators as well as changing the rotational\\u000a speed. The experimental results show that the off-design

YanMing Hu; ChaoQun Nie

2010-01-01

148

Bispectrum of stator phase current for fault detection of induction motor.  

PubMed

A number of research studies has shown that faults in a stator or rotor generally show sideband frequencies around the mains frequency (50 Hz) and at higher harmonics in the spectrum of the Motor Current Signature Analysis (MCSA). However in the present experimental studies such observations have not been seen, but any fault either in the stator or the rotor may distort the sinusoidal response of the motor RPM and the mains frequency so the MCSA response may contain a number of harmonics of the motor RPM and the mains frequency. Hence the use of a higher order spectrum (HOS), namely the bispectrum of the MCSA has been proposed here because it relates both amplitude and phase of number of the harmonics in a signal. It has been observed that it not only detects early faults but also indicates the severity of the fault to some extent. PMID:19394927

Treetrong, Juggrapong; Sinha, Jyoti K; Gu, Fengshu; Ball, Andrew

2009-04-23

149

Quantitative comparison of double-stator and traditional permanent magnet brushless machines  

NASA Astrophysics Data System (ADS)

In this paper, both the steady-state and dynamic performances of the double-stator permanent magnet brushless (DS-PMB) machines, including the surface-mounted topology (DS-SPMB) and the interior topology (DS-IPMB), are quantitatively compared with that of the traditional single-stator SPMB (SS-SPMB) machine. Based on the same electric loading and magnetic loading, the DS-SPMB and DS-IPMB machines are designed to have the same output power, while the DS-SPMB and SS-SPMB machines are of the same peripheral dimensions. The steady-state and transient characteristics of these machines are simulated by using the circuit-field-torque time-stepping finite element method. Finally, the preferred machine, namely, the DS-SPMB one, is prototyped and tested for experimental verification.

Niu, Shuangxia; Chau, K. T.; Yu, Chuang

2009-04-01

150

Design and control of a flux-controllable stator-permanent magnet brushless motor drive  

NASA Astrophysics Data System (ADS)

In this paper, a new flux-controllable stator permanent magnet (PM) brushless motor drive is proposed which is particularly attractive for electric vehicles. The key of the proposed motor is to incorporate both PM materials and dc field windings in the stator, hence offering a compact arrangement of hybrid-field excitations, while the rotor is simply composed of salient poles without windings or PMs. Thus, the flux control, including both strengthening and weakening, can be easily achieved by tuning the dc field current. Both finite element analysis and experimental results confirm that the proposed motor drive can offer effective flux control, fast speed response, wide constant-power operating range, and high efficiency over wide-speed operation.

Zhu, Xiaoyong; Chau, K. T.; Cheng, Ming; Yu, Chuang

2008-04-01

151

System and method for determining stator winding resistance in an AC motor  

DOEpatents

A system and method for determining stator winding resistance in an AC motor is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of an AC motor. The circuit includes at least one contactor and at least one switch to control current flow and terminal voltages in the AC motor. The system also includes a controller connected to the circuit and configured to modify a switching time of the at least one switch to create a DC component in an output of the system corresponding to an input to the AC motor and determine a stator winding resistance of the AC motor based on the injected DC component of the voltage and current.

Lu, Bin (Kenosha, WI); Habetler, Thomas G. (Snellville, GA); Zhang, Pinjia (Atlanta, GA); Theisen, Peter J. (West Bend, WI)

2011-05-31

152

System and method for determining stator winding resistance in an AC motor using motor drives  

DOEpatents

A system and method for determining the stator winding resistance of AC motors is provided. The system includes an AC motor drive having an input connectable to an AC source and an output connectable to an input terminal of an AC motor, a pulse width modulation (PWM) converter having switches therein to control current flow and terminal voltages in the AC motor, and a control system connected to the PWM converter. The control system generates a command signal to cause the PWM converter to control an output of the AC motor drive corresponding to an input to the AC motor, selectively generates a modified command signal to cause the PWM converter to inject a DC signal into the output of the AC motor drive, and determines a stator winding resistance of the AC motor based on the DC signal of at least one of the voltage and current.

Lu, Bin; Habetler, Thomas G; Zhang, Pinjia

2013-02-26

153

The interaction of an array of circumferentially varying stators with a uniform crossflow  

NASA Astrophysics Data System (ADS)

A propuslor capable of producing maneuvering forces in all directions effectively eliminates the need for additional control surfaces. Side forces can be generated by the propeller through the variation of the inflow swirl velocity to a conventional propeller. These control forces are generated based on the same geometric principles as a helicopter swash-plate. Instead of cyclically adjusting the propeller blade pitch angle, the relative pitch angle of a fixed pitch propeller is cyclically altered through a preswirled inflow generated by an upstream stator row. Wind tunnel experiments were conducted where global and detailed flow measurements were acquired through surface static pressure, and stereoscopic PIV on a simplified propulsor model. From these measurements a better understanding of the fluidic interactions associated with the non-uniform upstream stator row and the flow field was achieved.

Farnsworth, John; Amitay, Michael

2009-11-01

154

Unsteady heat transfer in stator-rotor interaction by two-equation turbulence model  

SciTech Connect

A transonic turbine stage is computed by means of an unsteady Navier-Stokes solver. A two-equation turbulence model is coupled to a transition model based on integral parameters and an extra transport equation. The transonic stage is modeled in two dimensions with a variable span height for the rotor row. The analysis of the transonic turbine stage with stator trailing edge coolant ejection is carried out to compute the unsteady pressure and heat transfer distribution on the rotor blade under variable operating conditions. The stator coolant ejection allows the total pressure losses to be reduced, although no significant effects on the rotor heat transfer are found both in the computer simulation and the measurements. The results compare favorable with experiments in terms of both pressure distribution and heat transfer around the rotor blade.

Michelassi, V.; Martelli, F, [Univ. of Florence, (Italy). Energetics Dept. Sergio Stecco; Denos, R.; Arts, T.; Sieverding, C.H. [von Karman Inst. for Fluid Dynamics, Rhode Saint Genese (Belgium)

1999-07-01

155

Study on the Ring Type Stator Design Technique for a Traveling Wave Rotary Type Ultrasonic Motor  

NASA Astrophysics Data System (ADS)

In this paper, the technique of design for the stator of traveling wave rotary type ultrasonic motor was proposed. To establish the design technique, the distribution of internal stresses of the stator was analyzed by applying the cylindrical bodies contact model of Hertz theory and the concept of ``horn effect'' was used to consider the influence of the projection structure. To verify the proposed technique, the prototype motor was fabricated on the authority of the projection shape dimension and the design specification. And its performance was evaluated. According to the estimate production of the experiment results using the extrapolation, we confirmed that the values obtained through the verification experiment were similar to those deduced by the proposed method properly.

Oh, Jin-Heon; Yuk, Hyung-Sang; Lim, Kee-Joe

2012-09-01

156

A novel stator resistance estimation method for speed-sensorless induction motor drives  

Microsoft Academic Search

A method for online estimation of the stator resistance of an induction machine is presented and a speed-sensorless field-oriented drive equipped with the proposed estimator is built. The drive is particularly suitable for low-speed operation. Resistance estimation is based on a two-time-scale approach, and the error between measured and observed current is used for parameter tuning. The simple full-order observer

Giuseppe Guidi; Hidetoshi Umida

2000-01-01

157

What stator current processing-based technique to use for induction motor rotor faults diagnosis?  

Microsoft Academic Search

In recent years, marked improvement has been achieved in the design and manufacture of stator winding. However, motors driven by solid-state inverters undergo severe voltage stresses due to rapid switch-on and switch-off of semiconductor switches. Also, induction motors are required to operate in highly corrosive and dusty environments. Requirements such as these have spurred the development of vastly improved insulation

Mohamed El Hachemi Benbouzid; Gerald B. Kliman

2003-01-01

158

A microcontroller-based sensorless stator flux-oriented asynchronous motor drive for traction applications  

Microsoft Academic Search

A sensorless stator flux-oriented asynchronous motor drive has been realized by using a low-cost single-chip microcontroller. A motor state observer has been implemented, which showed excellent performances, particularly at low-speed operation. Two different experimental realizations have been developed, with rated powers equal to about 1.5 and 30 kW, respectively, and good results have been obtained in both cases. The theoretical

Valter Lovati; Mario Marchesoni; Maurizio Oberti; Paolo Segarich

1998-01-01

159

Stator-flux-oriented vector control of synchronous reluctance Machines with maximized efficiency  

Microsoft Academic Search

This paper presents a position-sensorless vector torque controller designed to achieve maximum efficiency over a range of power and rotational speed for a synchronous reluctance machine. A model of the synchronous reluctance machine is presented which incorporates both winding and core losses. It is then shown that a stator-flux-oriented control scheme can achieve synchronous operation of the machine without a

Heath F. Hofmann; Seth R. Sanders; A. EL-Antably

2004-01-01

160

Optimal design and comparison of stator winding configurations in permanent magnet assisted synchronous reluctance generator  

Microsoft Academic Search

This paper presents design of high performance permanent magnet-assisted synchronous reluctance generators (PMa-SynRG) for 3 kW tactical quiet generator set. Adding the proper quantity of permanent magnets into the synchronous reluctance generator rotor core can offer large constant power-speed range, high efficiency and high power factor. Different stator winding configurations such as distributed windings and concentrated windings are compared using

Jeihoon Baek; Mina M. Rahimian; Hamid A. Toliyat

2009-01-01

161

Comparison of outer-rotor stator-permanent-magnet brushless motor drives for electric vehicles  

Microsoft Academic Search

In this paper, two emerging outer-rotor stator-permanent-magnet (PM) brushless motor drives, namely the doubly-salient PM motor drive and the PM hybrid brushless motor drive, are firstly quantitatively compared, which are particularly attractive for serving as in-wheel motor drives for electric vehicles. In order to enable a fair comparison, these two motor drives are designed with the same peripheral dimensions and

K. T. Chau; Chunhua Liu; J. Z. Jiang

2008-01-01

162

Design and analysis of a novel stator hybrid excited doubly salient permanent magnet brushless motor  

Microsoft Academic Search

Permanent magnet (PM) machines have been used widely for industrial applications. However, the operating speed range in most of these applications is very limited due to the difficulty of achieving field weakening in most PM machines. In this paper, a novel 12\\/8-pole stator hybrid excited doubly salient permanent magnet (SHEDS-PM) brushless motor capable of field weakening is proposed. By using

Xiaoyong Zhu; Ming Cheng; Wenguang Li

2005-01-01

163

High-speed axial-flux permanent-magnet generator with coreless stator  

Microsoft Academic Search

High-speed axial-flux generators (HSAFGs) with coreless stators are regarded as high-power-density, small-size, high-efficiency machines for use in distributed power generation systems (as microturbines). This paper presents a modelling procedure for such generators with details. The ratio of inner to outer diameter (lambda) in axial-flux machines is considered in the same way that the ratio of length to diameter is considered

M. Sadeghierad; H. Lesani; H. Monsef; A. Darabi

2009-01-01

164

Instantaneous magnetic field distribution in brushless permanent magnet DC motors. III. Effect of stator slotting  

Microsoft Academic Search

For pt.II see ibid., vol.29, no.1, p.136-142 (1993). A method for modeling the effect of stator slotting on the magnetic field distribution in the airgap\\/magnet region of a radial-field brushless permanent-magnet DC motor equipped with a surface-mounted magnet rotor is presented to allow the analytical prediction of the open-circuit, armature-reaction, and consultant magnetic field distribution under any specified load condition.

Z. Q. Zhu; D. Howe

1993-01-01

165

Two flagellar stators and their roles in motility and virulence in Pseudomonas syringae pv. tabaci 6605  

Microsoft Academic Search

The motor proteins around the flagellar basal body consist of two cytoplasmic membrane proteins, MotA and MotB, and function\\u000a as a complex that acts as the stator to generate the torque that drives rotation. Genome analysis of several Pseudomonas syringae pathovars revealed that there are two sets of genes encoding motor proteins: motAB and motCD. Deduced amino acid sequences for

Eiko Kanda; Takafumi Tatsuta; Tomoko Suzuki; Fumiko Taguchi; Kana Naito; Yoshishige Inagaki; Kazuhiro Toyoda; Tomonori Shiraishi; Yuki Ichinose

2011-01-01

166

Numerical modeling of heat transfer and fluid flow in rotor–stator cavities with throughflow  

Microsoft Academic Search

The present study considers the numerical modeling of the turbulent flow in a rotor–stator cavity subjected to a superimposed throughflow with heat transfer. Numerical predictions based on one-point statistical modeling using a low Reynolds number second-order full stress transport closure are compared with experimental data available in the literature [E.M. Sparrow, J.L. Goldstein, Effect of rotation and coolant throughflow on

S. Poncet; R. Schiestel

2007-01-01

167

Influence of rise time on the dielectric behavior of stator insulation materials  

Microsoft Academic Search

New rotating machine power supplies (inverters) produce voltage shapes whose characteristics are very different from the classical a.c ones. Up to now, their impacts' on stator insulation materials are not clearly understood. The most harmful parameters have been identified. These are the waveform (square or pulse like), the rise time (>kv\\/?s) and the high frequency solicitation (kHz). These stresses have

J. P. Bellomo; T. Lebey; J. M. Oraison; F. Peltier

1996-01-01

168

Punching influence on magnetic properties of the stator teeth of an induction motor  

Microsoft Academic Search

In order to study the effects of punching of electrical steel sheets, a suitable geometrical structure able to characterize the stator teeth behavior of an induction motor is proposed and validated. The influence of the punching on a fully processed M330-65A is then characterized. A spectacular degradation of loss and B(H) curves is observed. This leads to a perceptible increase

A. Kedous-Lebouc; B. Cornut; J. C Perrier; Ph. Manfé; Th. Chevalier

2003-01-01

169

Locating of leaks in water-cooled generator stator bars using perfluorocarbon tracers  

SciTech Connect

Water cooled stator bars in power plant generators often fail during the maintenance cycle due to water leakage. After the hydrogen pressure in the generator shell has been released water can leak through cracks in the copper and through the insulation. Leaking bars, but not the leaks themselves, are detected with so-called ``hi-pot`` (high potential) tests where direct electrical current is applied to the stator bar windings. A study initiated by ConEd and Brookhaven`s Tracer Technology Center to explore the cause of these leakage problems to determine if the failures originate in the manufacturing process or are created in service by phase related torque stresses. To this purpose bars that had failed the hi-pot test were investigated first with the insulation in place and then stripped to the bare copper. The bars were pressurized with gases containing perfluorocarbon tracers and the magnitude and location of the leaks was detected by using tracers technology principles and instruments such as the ``double source`` method and the Dual Trap Analyzer. In the second part of the project the windings within a generator were tested in-situ for leaks during an outage using tracer principles. Recommendations are given suggesting the shut down of stator bar cooling water before hydrogen bleeding during outages and a revision of the current vent flow rate. The new standard should establish a reasonable leak rate for the stator bar windings proper and exclude leakage of pump seals and connections. Testing during the maintenance cycle in generators should include routine tracer leak detection following the hi-pot test.

Loss, W.M.; Dietz, R.N.

1991-09-01

170

Locating of leaks in water-cooled generator stator bars using perfluorocarbon tracers  

SciTech Connect

Water cooled stator bars in power plant generators often fail during the maintenance cycle due to water leakage. After the hydrogen pressure in the generator shell has been released water can leak through cracks in the copper and through the insulation. Leaking bars, but not the leaks themselves, are detected with so-called hi-pot'' (high potential) tests where direct electrical current is applied to the stator bar windings. A study initiated by ConEd and Brookhaven's Tracer Technology Center to explore the cause of these leakage problems to determine if the failures originate in the manufacturing process or are created in service by phase related torque stresses. To this purpose bars that had failed the hi-pot test were investigated first with the insulation in place and then stripped to the bare copper. The bars were pressurized with gases containing perfluorocarbon tracers and the magnitude and location of the leaks was detected by using tracers technology principles and instruments such as the double source'' method and the Dual Trap Analyzer. In the second part of the project the windings within a generator were tested in-situ for leaks during an outage using tracer principles. Recommendations are given suggesting the shut down of stator bar cooling water before hydrogen bleeding during outages and a revision of the current vent flow rate. The new standard should establish a reasonable leak rate for the stator bar windings proper and exclude leakage of pump seals and connections. Testing during the maintenance cycle in generators should include routine tracer leak detection following the hi-pot test.

Loss, W.M.; Dietz, R.N.

1991-09-01

171

Finite-element analysis of the rotor/stator contact in a ring-type ultrasonic motor.  

PubMed

A way to understand mechanical characteristics of an ultrasonic motor is presented. First, the vibration mode of a stator is calculated using a finite-element method (FEM) code. The path of the elliptic motion of the stator's teeth is obtained. The computed vibration mode at the surface of the stator is compared with that measured by an electrooptical displacement transducer. Next, the contact condition of the rotor/stator is calculated. The displacement and velocity of the rotor/stator, the distortion of the stick/slip area, the rotational speed of the rotor, and the friction loss of the motor are obtained. The calculated rotor displacement and torque-rotational speed curve correspond closely to the experimentally measured ones. The internal loss of the rotor/stator and the loss of the supporting felt are measured. The total loss of these losses and the calculated friction loss agree with the measured total loss. The calculated and the measured efficiency of the motor also agree. PMID:18267680

Maeno, T; Tsukimoto, T; Miyake, A

1992-01-01

172

Detection of leaks in a water-cooled generator stator bar using perfluorocarbon tracers  

SciTech Connect

A generator stator bar with a suspected leak was removed from the ConEdison Ravenswood power plant and shipped to an independent laboratory for hydraulic pressure testing. The test failed to demonstrate the location and magnitude of leaks. The stator bar was subsequently investigated at Brookhaven's Tracer Technology Center. Pressurization with 3 ppM PMCP (perfluoromethylcyclopentane) in hydrogen as carrier gas revealed a leak close to the turbine end of the generator. The equivalent water leak rate was calculated to be about 1/2 mL per day at 30 psi water pressure. A series of tests was designed to first verify the existence of potential leaks and then to locate these leaks as accurately as possible. Enclosing the bar in a flexible hose, introducing nitrogen gas into the hose and analyzing the hose exhaust with Brookhaven's Dual Trap Analyzer successfully identified the existence of leaks. However, the technique failed to locate the approximation position of the suspected leaks. It was found that diffusion and the existence of a laminar flow regime inside the hose prevented the formation of uniform concentration levels and, hence, consistent readings. Successful leak pinpointing was accomplished by wrapping short sections of the bar in plastic bags. This approach with some suggested improvements is also recommended for future experiments with stator bars. 6 figs., 1 tab.

Loss, W.M.; Dietz, R.N.; Senum, G.I.

1989-12-01

173

Measurement of attitude angles of single stator multi-degrees of freedom ultrasonic motor  

NASA Astrophysics Data System (ADS)

In order to measure the attitude angles of our ultrasonic motor, a compact single stator multi-degree-of freedom (DOF) ultrasonic motor with a cylindrical stator and a spherical rotor is designed with one OEM encoder and 2D PSD (Position Sensitive Detector) sensor. The spherical rotor is rotated around three perpendicular axes by three natural vibrations excited on the stator. The OEM encoder disc is fixed on the rotor output shaft to measure the rotational angle of the output shaft. The PSD sensor is installed in loading sphere, and one LED is installed in the LED house, the line light emitted by the LED transmits along the output shaft axis and passes through the center of the spherical rotor, and then projects on the PSD surface, and the PSD and LED comprise the device to measure the pitch and roll of the rotor. The output current signals of the PSD sensor are changed into voltages, amplified by measuring circuits, converted into digital signals, and are transmitted to MCU. The attitude angles of the motor are calculated out using the proposed algorithm. The compact structure design of the motor makes the measurement of the attitude angles of the multi-DOF ultrasonic motor more practical and convenient.

Liu, Wu-Fal; Tao, Zheng; Zhang, Lin-Na; Gao, Jian-She; Zhao, Feng-Xia; Zhen, Peng

2010-08-01

174

Stator-Interturn-Fault Detection of Doubly Fed Induction Generators Using Rotor-Current and Search-Coil-Voltage Signature Analysis  

Microsoft Academic Search

A novel technique for detecting stator interturn faults in a doubly fed induction generator (DFIG) is proposed by analyzing its rotor current and search-coil voltage. So far, fault-diagnostic techniques proposed for stator-interturn-fault detection in DFIGs are based on analysis of stator current or vibration of generator. Results from these methods are ambiguous because they either fail to account for condition

Dhaval Shah; Subhasis Nandi; Prabhakar Neti

2009-01-01

175

Numerical Analysis of the Unsteady Rotor-Stator Interaction in a Low Pressure Centrifugal Compressor by Using Adamczyk and Proper Orthogonal Decompositions  

NASA Astrophysics Data System (ADS)

The aim of this paper is to study the unsteady rotor-stator interaction in a low pressure centrifugal compressor using the finite volume method to solve the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations. In order to understand better, the rotor-stator interaction, the unsteady results are processed using both Adamczyk decomposition and Proper Orthogonal Decomposition (POD). Both decompositions show the behavior of unsteady rotor-stator interaction but the POD modes also show the numerical errors.

Niculescu, Mihai Leonida; d?n?il?, Sterian

2010-09-01

176

Operation of a test bed axial-gap brushless dc rotor with a superconducting stator  

SciTech Connect

A variable-speed axial-gap motor with a stator consisting of four liquid helium cooled superconducting electromagnets (two pole pairs) was built and proof tested up to 608 rpm in November 1990 as a tool for joint industry-laboratory evaluation of coils fabricated from high-temperature oxide superconductors. A second rotor was fabricated with improved materia winding configuration, and wire type, and the drive system was modified to eliminate current spiking. The modified motor was characterized to design speed, 188 rad/s (1800 rpm), to acquire a performance baseline for future comparison with that of high-temperature superconducting (HIS) wire. As it becomes commercially available, HTS wire will replace the low-temperature electromagnet wire in a stator modified to control wire temperatures between 4 K and 77 K. Measurements of the superconducting electromagnetic field and locked rotor torque as functions of cryocurrent and dc current through two phases of the rotor, respectively, provided data to estimate power that could be developed by the rotor. Back emf and parasitic mechanical and electromagnetic drag torques were measured as functions of angular velocity to calculate actual rotor power developed and to quantify losses, which reduce the motor`s efficiency. A detailed measurement of motor power at design speed confirmed the developed power equation. When subsequently operated at the 33-A maximum available rotor current, the motor delivered 15.3 kill (20.5 hp) to the load. In a final test, the cryostat was operated at 2500 A, 200 A below its critical current. At rotor design current of 60 A and 2500 A stator current, the extrapolated developed power would be 44.2 kill (59.2 hp) with 94% efficiency.

McKeever, J.W.; Sohns, C.W.; Schwenterly, S.W.; Young, R.W. Sr.; Campbell, V.W.; Hickey, M.H.; Ott, G.W. [Oak Ridge National Lab., TN (United States); Bailey, J.M. [Tennessee Univ., Knoxville, TN (United States)

1993-08-01

177

Individual Interactions of the b Subunits within the Stator of the Escherichia coli ATP Synthase.  

PubMed

FOF1 ATP synthases are rotary nanomotors that couple proton translocation across biological membranes to the synthesis/hydrolysis of ATP. During catalysis, the peripheral stalk, composed of two b subunits and subunit ? in Escherichia coli, counteracts the torque generated by the rotation of the central stalk. Here we characterize individual interactions of the b subunits within the stator by use of monoclonal antibodies and nearest neighbor analyses via intersubunit disulfide bond formation. Antibody binding studies revealed that the C-terminal region of one of the two b subunits is principally involved in the binding of subunit ?, whereas the other one is accessible to antibody binding without impact on the function of FOF1. Individually substituted cysteine pairs suitable for disulfide cross-linking between the b subunits and the other stator subunits (b-?, b-?, b-?, and b-a) were screened and combined with each other to discriminate between the two b subunits (i.e. bI and bII). The results show the b dimer to be located at a non-catalytic ?/? cleft, with bI close to subunit ?, whereas bII is proximal to subunit ?. Furthermore, bI can be linked to subunit ? as well as to subunit a. Among the subcomplexes formed were a-bI-?, bII-?, ?-bI-bII-?, and a-bI-?. Taken together, the data obtained define the different positions of the two b subunits at a non-catalytic interface and imply that each b subunit has a different role in generating stability within the stator. We suggest that bI is functionally related to the single b subunit present in mitochondrial ATP synthase. PMID:23846684

Brandt, Karsten; Maiwald, Sarah; Herkenhoff-Hesselmann, Brigitte; Gnirß, Kerstin; Greie, Jörg-Christian; Dunn, Stanley D; Deckers-Hebestreit, Gabriele

2013-07-11

178

Rim seal experiments and analysis of a rotor-stator system with nonaxisymmetric main flow  

NASA Astrophysics Data System (ADS)

To examine the simplified model to predict the ingress flow rate which was formerly proposed by the authors, the sealing characteristics of a shrouded rotor-stator system with a nonaxisymmetric main flow is studied using gas concentration measurements in the wheel-space. The predicted value for the sealing effectiveness as well as the minimum cooling air flow ratio necessary to prevent ingress is shown to be relatively in good agreement with the test results. It is also found that for the precise prediction of the sealing effectiveness, the circumferential static pressure distribution in the annulus is needed.

Hamabe, K.; Ishida, K.

1992-06-01

179

Étude des structures spirales à la périphérie d'une cavité rotor stator aspirée  

NASA Astrophysics Data System (ADS)

The influence of suction on the spirals pattern that appear on the periphery of an aspirated opened rotor-stator cavity is studied by means of tomography. A radial gap, located between the rotating disk and the fixed cylindrical wall allow the suction of an outer flux made up of a jet of fresh air and a high contrasted smoke thin sheet produced in the outside cavity Ekman layer. Sequences of tomographies allow the characterization of the apparition and disappearance thresholds according to Reynolds number, suction and wave number. To cite this article: D. Rémy et al., C. R. Mecanique 332 (2004).

Rémy, David; Gauthier, Georges; Buisine, Daniel

2004-08-01

180

A lifting surface theory for the sound generated by the interaction of velocity disturbances with a leaned vane stator  

NASA Astrophysics Data System (ADS)

An unsteady 3-D lifting surface theory to predict the sound field of a stator with leaned, i.e., nonradial, vanes in an annular duct is presented. The duct carries a uniform subsonic main flow and is assumed to be anechoic. The sound is generated by the interaction of velocity disturbances with the stator vanes. The problem is formulated as an integral equation for the pressure jump across the vanes. This equation is solved by a Fourier series expansion, followed by a collocation procedure. The effect of vane lean on the sound field of a typical stator exposed to the viscous wake system of a rotor is studied. The modal distribution proves to be very sensitive to lean variation. Unless the rotor speed is very low (1 mode cut-on), no reduction of acoustic power at the blade passing frequency is found for any lean angle. On the contrary, even a moderate amount of lean raises the power significantly.

Schulten, J. B. H. M.

1981-01-01

181

Introduction of a new scaling approach for particle size reduction in toothed rotor-stator wet mills.  

PubMed

A new scaling approach has been demonstrated for particle size reduction of an active pharmaceutical ingredient (API) in toothed rotor-stator wet mills for a wide range of wet milling conditions and scales. Compound A was crystallized by a cooling crystallization protocol in ethanol and wet milled with 2 types of lab scale mills and 1 pilot plant mill. The particle size was analyzed by FBRM (focused beam reflectance measurement), static light scattering and optical microscopy. The correlation between particle size and the energy input calculations, tailored for the toothed rotor-stator wet mill, had R(2)=0.90 on a logarithmic plot. The new scaling approach forms the basis to correlate API particle size to energy input in toothed rotor-stator wet mills by accounting for wet mill tooth configuration and geometry, rotor tip speed and the probabilistic effects of collision such as shear frequency and slurry residence time. PMID:24012859

Engstrom, Joshua; Wang, Chenchi; Lai, Chiajen; Sweeney, Jason

2013-09-05

182

Achieving more reliable operation of turbine generators at nuclear power plants by improving the water chemistry of the generator stator cooling system  

NASA Astrophysics Data System (ADS)

Ways of improving the water chemistry used in the turbine generator stator's cooling systems at Russian nuclear power plants are considered. Data obtained from operational chemical monitoring of indicators characterizing the quality of cooling water in the turbine generator stator cooling systems of operating power units at nuclear power plants are presented.

Tyapkov, V. F.; Chudakova, I. Yu.; Alekseenko, O. A.

2011-08-01

183

Achieving more reliable operation of turbine generators at nuclear power plants by improving the water chemistry of the generator stator cooling system  

Microsoft Academic Search

Ways of improving the water chemistry used in the turbine generator stator's cooling systems at Russian nuclear power plants are considered. Data obtained from operational chemical monitoring of indicators characterizing the quality of cooling water in the turbine generator stator cooling systems of operating power units at nuclear power plants are presented.

V. F. Tyapkov; I. Yu. Chudakova; O. A. Alekseenko

2011-01-01

184

Influence of slot opening on optimal stator and rotor pole combination and electromagnetic performance of flux-switching PM brushless AC machines  

Microsoft Academic Search

The significant influence of slot opening on the optimal stator and rotor pole combination and the electromagnetic performance of the flux-switching PM (FSPM) machine is observed and investigated in this paper. A new FSPM brushless machine with remarkable slot opening relative to the magnet thickness is developed to reduce the magnet usage and increase the slot area. Its stator slot

J. T. Chen; Z. Q. Zhu; S. Iwasaki; R. Deodhar

2010-01-01

185

An Active Stator Temperature Estimation Technique for Thermal Protection of Inverter-Fed Induction Motors With Considerations of Impaired Cooling Detection  

Microsoft Academic Search

Thermal protection is one of the most important aspects of any motor control system. This paper proposes a stator winding temperature estimation method for the thermal protection of inverter-fed electric motors. By modifying the space vector pulsewidth modulation in an open-loop motor drive, a dc voltage can be intermittently injected into the motor. The stator temperature can be estimated by

Pinjia Zhang; Bin Lu; Thomas G. Habetler

2010-01-01

186

An active stator temperature estimation technique for thermal protection of inverter-fed induction motors with considerations of impaired cooling detection  

Microsoft Academic Search

Thermal protection is one of the most important aspects of any motor control system. This paper proposes a stator winding temperature estimation method for the thermal protection of inverter-fed electric motors. By modifying the space vector pulse width modulation (SVPWM) in an open-loop motor drive, a dc voltage can be intermittently injected into the motor. The stator temperature can be

Pinjia Zhang; Bin Lu; Thomas G. Habetler

2009-01-01

187

The impact of different stator and rotor slot number combinations on iron losses of a three-phase induction motor at no-load  

Microsoft Academic Search

The electromechanical characteristics of induction motors depend on the used stator and rotor slot combination. The correlation between the usage of different stator and rotor slot number combinations, magnetic flux density distributions, no-load iron losses and rated load winding over-temperatures for a specific induction motor is presented. The motor's magnetic field was analyzed by traces of the magnetic flux density

T. Marcic; B. Stumberger; G. Stumberger; M. Hadziselimovic; I. Zagradisnik

2008-01-01

188

Calculation of forces on the stator end windings of turbogenerator by the transient quasi-3D method  

SciTech Connect

Lorentz formula is applied here to calculate the electromagnetic forces acting on the stator end windings of a turbogenerator within the first several periods after it is suddenly short circuited, based on the magnetic field computed by the transient quasi-3D method (TQM). The principle of TQM and its essence-processing of winding currents have been discussed. In the example, the forces acting on the stator end windings of a 35MW turbogenerator have been computed, when it is under no-load three phase, no-load line-to-line and no-load line-to-neutral sudden short circuit conditions. Some useful results are obtained.

Wen, X. [Chinese Academy of Sciences, Beijing (China). Inst. of Electrical Engineering; Yao, R. [Tsinghua Univ., Beijing (China). Dept. of Electrical Engineering; Tegopoulos, J.A. [National Technical Univ. of Athens (Greece). Dept. of Electrical Engineering

1996-05-01

189

Hydroacoustic simulation of rotor-stator interaction in resonance conditions in Francis pump-turbine  

NASA Astrophysics Data System (ADS)

Combined effect of rotating pressure field related to runner blade and wakes of wicket gates leads to rotor stator interactions, RSI, in Francis pump-turbines. These interactions induce pressures waves propagating in the entire hydraulic machine. Superposition of those pressure waves may result in standing wave in the spiral casing and rotating diametrical mode in the guide vanes and can cause strong pressure fluctuations and vibrations. This paper presents the modeling, simulation and analysis of Rotor-Stator Interaction of a scale model of a Francis pump-turbine and related test rig using a one-dimensional approach. The hydroacoustic modeling of the Francis pump-turbine takes into account the spiral casing, the 20 guide vanes, the 9 rotating runner vanes. The connection between stationary and rotating parts is ensured by a valve network driven according to the unsteady flow distribution between guide vanes and runner vanes. Time domain simulations are performed for 2 different runner rotational speeds in turbine mode. The simulation results are analyzed in frequency domain and highlights hydroacoustic resonance between RSI excitations and the spiral case. Rotating diametrical mode in the vaneless gap and standing wave in the spiral case are identified. The influence of the resonance on phase and amplitude of pressure fluctuations obtained for both the spiral case and the vaneless gap is analyzed. The mode shape and frequencies are confirmed using eigenvalues analysis.

Nicolet, C.; Ruchonnet, N.; Alligné, S.; Koutnik, J.; Avellan, F.

2010-08-01

190

Untersuchung des Stroemungsverhaltens von hochbelasteten ungekuehlten Niederdruck-Turbinengittern unter Berucksichtigung der Rotor-Stator Interaktion (Examination of Flow Behavior of Highly Loaded Uncooled Low-Pressure Turbine Grids with Regard to Rotor-Stator Interaction).  

National Technical Information Service (NTIS)

Tests are made on two highly loaded low-pressure turbine grids, which have been specially developed in order to make use of the positive effects of rotor-stator interaction, observing simultaneously the typical Mach and Reynolds number combinations. After...

S. Brunner

2000-01-01

191

An Adaptive Observer With Online Rotor and Stator Resistance Estimation for Induction Motors With One Phase Current Sensor  

Microsoft Academic Search

An adaptive observer with online estimation of rotor and stator resistances is considered for induction motors, while only one phase current is measured. Generally, an induction motor drive controller needs at least two phase-current sensors. Nevertheless, failure of one current sensor results in degradation of motor drive performance and reliability, and also state and parameter estima- tion errors. Furthermore, any

Farzad R. Salmasi; Tooraj Abbasian Najafabadi

2011-01-01

192

Averaging analysis approach for stability analysis of speed-sensorless induction motor drives with stator resistance estimation  

Microsoft Academic Search

In this paper, the stability property of speed-sensorless induction motor drives with stator resistance estimation is analyzed using the averaging analysis technique. Explicit stability conditions are then derived to clarify analytically when the instability may occur and how the regressor vectors used in the estimation and the integral adaptation gains should be designed to assure stability. The derived stability conditions

Mongkol Saejia; Somboon Sangwongwanich

2006-01-01

193

A COMPLETE STATOR AND ROTOR RESISTANCE IDENTIFIER FOR INDUCTION MOTOR DRIVE USING FUZZY LOGIC AND ARTIFICIAL NEURAL NETWORKS  

Microsoft Academic Search

This paper presents a new method of on-line estimation for the stator and rotor resistances of the induction motor in the indirect vector controlled drive, using fuzzy logic and artificial neural networks. The back propagation algorithm is used for the training of the neural networks for rotor resistance identification. The error between the desired state variable of an induction motor

B. Karanayil; M. F. Rahman; C. Grantham

194

Online Stator and Rotor Resistance Estimation Scheme Using Artificial Neural Networks for Vector Controlled Speed Sensorless Induction Motor Drive  

Microsoft Academic Search

This paper presents a new method of online estimation for the stator and rotor resistances of the induction motor for speed sensorless indirect vector controlled drives, using artificial neural networks. The error between the rotor flux linkages based on a neural network model and a voltage model is back propagated to adjust the weights of the neural network model for

Baburaj Karanayil; Muhammed Fazlur Rahman; Colin Grantham

2007-01-01

195

On-line stator and rotor resistance estimation scheme for vector-controlled induction motor drive using artificial neural networks  

Microsoft Academic Search

This paper presents a new method of on-line estimation for the stator and rotor resistances of the induction motor in the indirect vector controlled drive, using artificial neural networks. The back propagation algorithm is used for training of the neural networks. The error between the desired state variable of an induction motor and the actual state variable of a neural

Baburaj Karanayil; Muhammed Fazlur Rahman; Colin Grantham

2003-01-01

196

SSME (Space Shuttle Main Engine) Seal Test Program: Test Results for Smooth, Hole-Pattern and Helically-Grooved Stators.  

National Technical Information Service (NTIS)

All of the listed seals were tested in a liquid Halon test facility at high Reynolds numbers. In addition, a helically-grooved-stator seal was tested in an air seal facility. An analysis of the test results with comparisons to theoretical predictions supp...

D. W. Childs

1987-01-01

197

DSP implementation of the multiple reference frames theory for the diagnosis of stator faults in a DTC induction motor drive  

Microsoft Academic Search

This paper deals with the use of a new diagnostic technique, based on the multiple reference frame theory, for the diagnosis of stator winding faults in a direct torque controlled (DTC) induction motor drive. The theoretical aspects underlying the use of this diagnostic technique are presented but a major emphasis is given to the integration of the diagnostic system into

S. M. A. Cruz; H. A. Toliyat; A. J. M. Cardoso

2003-01-01

198

Detection of birdcaging in steel wire rope of a hoisting winch system by analysis of load torque and stator current  

Microsoft Academic Search

The aim of this paper is to analyze theoretically and experimentally the stator current of a three phase induction machine and load torque signals in a hoisting winch system, in order to show how they are influenced by the wire rope faulty condition. When the wire rope is subjected to axial and torsional loads, the outer strands can separate from

H. Henao; S. M. J. Rastegar Fatemi; S. Sieg-Zieba; G. A. Capolino

2009-01-01

199

4A-4 UHV Compatible Ultrasonic Motor: Operation keeping UHV and Durability Improvement by Modifying Rotor-Stator Interface  

Microsoft Academic Search

To meet with requirement for actuators that are fully nonmagnetic and compatible to ultrahigh vacuum (UHV), the authors have been developing an ultrasonic motor and researching on various phenomena relating to its operation in UHV. This motor is a cylindrical type or mode rotation type ultrasonic motor, on the stator of which is excited two standing waves. The modes are

Toshiki NIINO; Masahiro Michihata; Yasuhiro ENDO; Shintaro FUNAMI

2006-01-01

200

Design and testing of swept and leaned outlet guide vanes to reduce stator-strut-splitter aerodynamic flow interactions  

Microsoft Academic Search

Large circumferentially varying pressure levels produced by aerodynamic flow interactions between downstream stators and struts present a potential noise and stability margin liability in a compression component. These interactions are presently controlled by tailoring the camber and\\/or stagger angles of vanes neighboring the fan frame struts. This paper reports on the design and testing of a unique set of swept

A. R. Wadia; P. N. Szucs; K. L. Gundy-Burlet

1999-01-01

201

The physical phenomena associated with stator winding insulation condition as detected by the ramped direct high-voltage method  

Microsoft Academic Search

Deregulation of the electric utility industry has increased the need to monitor the state of powerplant equipment, such as critical generators and motors, to improve availability and reduce life cycle costs via condition-based maintenance. To achieve these goals, nondestructive condition assessment and diagnostic tests are necessary to evaluate the quality and condition of a machine's stator winding insulation system. Periodic

Lorelynn Mary Rux

2004-01-01

202

Impact of stator windings and end-bells on resonant frequencies and mode shapes of switched reluctance motors  

Microsoft Academic Search

One of the main drawbacks of switched reluctance motors (SRMs) is vibration and acoustic noise, which limits their application. An accurate predication of the modal vibration frequencies of the SRM stator is essential in order to design a low-vibration motor and operate it quietly. Electronic techniques for noise reduction also depend on knowledge of the resonant frequencies, which depend on

Wei Cai; Pragasen Pillay; Zhangjun Tang

2002-01-01

203

Environmentally Based Maternal Effects on Development Time in the Seed Beetle Stator pruininus (Coleoptera: Bruchidae): Consequences of Larval Density  

Microsoft Academic Search

In response to food limitation, many insects have evolved developmental plasticity in which larvae mature at a smaller body size. Here we investigate the consequences of this smaller body size for development of individuals in the next generation, after resource competition has been relaxed. Families of the seed beetle Stator pruininus (Horn) reared at high density ('20 eggs per seed)

CHARLES W. FOX; MARY ELLEN CZESAK; UDO M. SAVALLI

1999-01-01

204

Two rotary motors in F-ATP synthase are elastically coupled by a flexible rotor and a stiff stator stalk.  

PubMed

ATP is synthesized by ATP synthase (F(O)F(1)-ATPase). Its rotary electromotor (F(O)) translocates protons (in some organisms sodium cations) and generates torque to drive the rotary chemical generator (F(1)). Elastic power transmission between F(O) and F(1) is essential for smoothing the cooperation of these stepping motors, thereby increasing their kinetic efficiency. A particularly compliant elastic domain is located on the central rotor (c(10-15)/?/?), right between the two sites of torque generation and consumption. The hinge on the active lever on subunit ? adds further compliance. It is under contention whether or not the peripheral stalk (and the "stator" as a whole) also serves as elastic buffer. In the enzyme from Escherichia coli, the most extended component of the stalk is the homodimer b(2), a right-handed ?-helical coiled coil. By fluctuation analysis we determined the spring constant of the stator in response to twisting and bending, and compared wild-type with b-mutant enzymes. In both deformation modes, the stator was very stiff in the wild type. It was more compliant if b was elongated by 11 amino acid residues. Substitution of three consecutive residues in b by glycine, expected to destabilize its ?-helical structure, further reduced the stiffness against bending deformation. In any case, the stator was at least 10-fold stiffer than the rotor, and the enzyme retained its proton-coupled activity. PMID:21368147

Wächter, André; Bi, Yumin; Dunn, Stanley D; Cain, Brian D; Sielaff, Hendrik; Wintermann, Frank; Engelbrecht, Siegfried; Junge, Wolfgang

2011-02-22

205

The speed and position sensorless control of PMSM using the sliding mode observer with the estimator of stator resistance  

Microsoft Academic Search

This paper presents a new speed and position sensorless control method of permanent magnet synchronous motors based on a sliding mode observer. The sliding mode observer structure and its design method are described. Also, Lyapunov functions are chosen for determining the adaptive law for the speed and the stator resistance estimator. The effectiveness of the proposed observer is confirmed by

Yoon-Seok Han; Young-Seok Kim

1999-01-01

206

Sensorless Indirect-Rotor-Field-Orientation Speed Control of a Permanent-Magnet Synchronous Motor With Stator-Resistance Estimation  

Microsoft Academic Search

Efficient and precise sensorless speed control of a permanent-magnet synchronous motor (PMSM) requires accurate knowledge of rotor flux, position, and speed. In the literature, many sensorless schemes have been presented, in which the accurate estimation of rotor flux magnitude, position, and speed is guaranteed by detecting the back electromotive force (EMF). However, these schemes show great sensitivity to stator resistance

Mohamed Rashed; Peter F. A. MacConnell; A. Fraser Stronach; Paul Acarnley

2007-01-01

207

Study on piezoelectric ceramic\\/metal composite thin plate of driving stator for travelling-wave motor  

Microsoft Academic Search

In this paper the solution of general problems of the bending vibration of the thin piezoelectric ceramic\\/metal composite plate of a driving stator for a travelling-wave motor was analysed. Considering the electromechanical coupling effect, the concepts of generalized stress and strain and generalized piezoelectric equations were introduced. The relation of generalized stress and strain, satisfying the differential motion equation of

Shuxiang Dong; Longtu Li; Xiaowen Zhang

1994-01-01

208

Étude par la PIV des structures à la périphérie d'une cavité rotor–stator aspirée  

Microsoft Academic Search

We experimentally study the three-dimensional structure of the spiral instability observed on the periphery of a opened rotor–stator cavity with suction. We use the stereoscopic Particles Images Velocimetry technique which gives sequences of maps of the three velocity components of fluid particles located in a meridian plane. This sequence is acquired with a low frequency during the running of a

David Rémy; Nicolas Pérenne; Jean-Marc Foucaut; Daniel Buisine

2004-01-01

209

An evaluation of alternative stator lamination materials for a high-speed, 1.5 MW, permanent magnet generator  

Microsoft Academic Search

The influence of the choice of stator lamination material on the iron loss in a high speed, high power permanent magnet generator, which is interfaced to a DC link via a simple bridge rectifier, is investigated. The rating of the generator is representative of machines which would be employed in 'more-electric' ships and for embedded power generation. It is shown

Johannes J. H. Paulides; Geraint W. Jewell; David Howe

2004-01-01

210

Two rotary motors in F-ATP synthase are elastically coupled by a flexible rotor and a stiff stator stalk  

PubMed Central

ATP is synthesized by ATP synthase (FOF1-ATPase). Its rotary electromotor (FO) translocates protons (in some organisms sodium cations) and generates torque to drive the rotary chemical generator (F1). Elastic power transmission between FO and F1 is essential for smoothing the cooperation of these stepping motors, thereby increasing their kinetic efficiency. A particularly compliant elastic domain is located on the central rotor (c10–15/?/?), right between the two sites of torque generation and consumption. The hinge on the active lever on subunit ? adds further compliance. It is under contention whether or not the peripheral stalk (and the “stator” as a whole) also serves as elastic buffer. In the enzyme from Escherichia coli, the most extended component of the stalk is the homodimer b2, a right-handed ?-helical coiled coil. By fluctuation analysis we determined the spring constant of the stator in response to twisting and bending, and compared wild-type with b-mutant enzymes. In both deformation modes, the stator was very stiff in the wild type. It was more compliant if b was elongated by 11 amino acid residues. Substitution of three consecutive residues in b by glycine, expected to destabilize its ?-helical structure, further reduced the stiffness against bending deformation. In any case, the stator was at least 10-fold stiffer than the rotor, and the enzyme retained its proton-coupled activity.

Wachter, Andre; Bi, Yumin; Dunn, Stanley D.; Cain, Brian D.; Sielaff, Hendrik; Wintermann, Frank; Engelbrecht, Siegfried; Junge, Wolfgang

2011-01-01

211

Analytically computing the flux linked by a switched reluctance motor phase when the stator and rotor poles overlap  

Microsoft Academic Search

This paper develops an analytical model for the flux linked by a phase of a switched reluctance motor (SRM) starting with the basic laws for magnetic fields. Thus this model is not empirical nor does it require any data from the machine being modeled or any finite-element analysis results. The model is applicable to rotor positions where the stator and

Arthur Radun

2000-01-01

212

Effect of pole to slot number ratio on back-EMF constant of BLDC motor with nonoverlapping stator winding  

Microsoft Academic Search

This paper presents a general expression of back-EMF constant of 3-phase permanent magnet brushless DC (BLDC) motor with nonoverlapping stator winding. From the expression, any possible combinations of pole and slot numbers are found and the value of back-EMF constant is compared in the several cases of different pole to slot number ratios and airgap flux density waveforms

Han-Sam Cho; Hyun-Rae Cho; Hae-Seok Lee

1999-01-01

213

Numerical simulation of the effects of rotor-stator spacing and wake/blade count ratio on turbomachinery unsteady flows  

SciTech Connect

A two-dimensional time-accurate Navier-Stokes solver for incompressible flows is used to simulate the effects of the axial spacing between an upstream rotor and a stator, and the wake/blade count ratio on turbomachinery unsteady flows. The code uses a pressure-based method. A low-Reynolds number two-equation turbulence model is incorporated to account for the turbulence effect. By computing cases with different spacing between an upstream rotor wake and a stator, the effect of the spacing is simulated. Wake/blade count ratio effect is simulated by varying the number of rotor wakes in one stator passage at the computational inlet plane. Results on surface pressure, unsteady velocity vectors, blade boundary layer profiles, rotor wake decay and loss coefficient for all the cases are interpreted. It is found that the unsteadiness in the stator blade passage increases with a decrease in the blade row spacing and a decrease in the wake/blade count ratio. The reduced frequency effect is dominant in the wake/blade count ratio simulation. The time averaged loss coefficient increases with a decrease in the axial blade row spacing and an increase in the wake/blade count ratio.

Yu, W.S.; Lakshminarayana, B. [Pennsylvania State Univ., University Park, PA (United States). Center for Gas Turbines and Power

1995-12-01

214

Fault diagnosis for stator winding bar hollow strand blockage of turbogenerators based on data fusion  

NASA Astrophysics Data System (ADS)

Stator Winding Bar Hollow Strand Blockage (SWBHSB) is one of the main faults for large turbo-generators with water and hydrogen cooling system. It will lead to increasing water temperature at the bar exit which may cause hidden troubles for turbo-generator's security. According to a three-layer-structural model of data fusion, this paper presents a fault diagnosis method for turbo-generators based on data fusion technology. Firstly, a bp network on pixel level fusion is set up, in which several temperature parameters at the bar exit are accurately computed. Then in feature level fusion, the fingerprints are distilled from the result of pixel level fusion. Finally, decision level fusion gives a fault diagnosis for the measuring channels and thermometric components. This method can effectively avoid problems such as misinformation and fake report.

Wang, Xianpei; Dai, Zheng Y.; Liu, Zhenxing; Chen, Yalin

2003-09-01

215

BRIEF COMMUNICATION: Piezoelectric ultrasonic resonant motor with stator diameter less than 250 µm: the Proteus motor  

NASA Astrophysics Data System (ADS)

Minimally invasive and in vivo surgery is limited by the ability to provide controllable and powerful motion at scales appropriate for navigation within the human body. A motor for in vivo microbot propulsion is presented with a stator diameter of phi250 µm, demonstrating the potential to directly drive a flagellum for swimming at up to 1295 rpm with a torque of 13 nN m. The motor uses coupled axial-torsional vibration at 652-682 kHz in a helically cut structure excited by a thickness-polarized piezoelectric element. The output power is 4.25 µW, on the order of what is necessary to navigate small human arteries.

Watson, B.; Friend, J.; Yeo, L.

2009-02-01

216

Sensorless speed detection of squirrel-cage induction machines using stator neutral point voltage harmonics  

NASA Astrophysics Data System (ADS)

In this paper a sensorless speed detection method of induction squirrel-cage machines is presented. This method is based on frequency determination of the stator neutral point voltage primary slot harmonic, which is dependent on rotor speed. In order to prove method in steady state and dynamic conditions the simulation and experimental study was carried out. For theoretical investigation the mathematical model of squirrel cage induction machines, which takes into consideration actual geometry and windings layout, is used. Speed-related harmonics that arise from rotor slotting are analyzed using digital signal processing and DFT algorithm with Hanning window. The performance of the method is demonstrated over a wide range of load conditions.

Petrovic, Goran; Kilic, Tomislav; Terzic, Bozo

2009-04-01

217

Crystal structure of yeast V-ATPase subunit C reveals its stator function  

PubMed Central

Vacuolar H+-ATPase (V-ATPase) has a crucial role in the vacuolar system of eukaryotic cells. It provides most of the energy required for transport systems that utilize the proton-motive force that is generated by ATP hydrolysis. Some, but not all, of the V-ATPase subunits are homologous to those of F-ATPase and the nonhomologous subunits determine the unique features of V-ATPase. We determined the crystal structure of V-ATPase subunit C (Vma5p), which does not show any homology with F-ATPase subunits, at 1.75 Å resolution. The structural features suggest that subunit C functions as a flexible stator that holds together the catalytic and membrane sectors of the enzyme. A second crystal form that was solved at 2.9 Å resolution supports the flexible nature of subunit C. These structures provide a framework for exploring the unique mechanistic features of V-ATPases.

Drory, Omri; Frolow, Felix; Nelson, Nathan

2004-01-01

218

Interaction of a circumferentially varying stator row upstream of a propeller in a uniform flow  

NASA Astrophysics Data System (ADS)

A propuslor capable of producing maneuvering forces in all directions effectively eliminates the need for additional control surfaces. Side forces can be generated by the propeller through the variation of the inflow swirl velocity to a conventional propeller. These control forces are generated based on the same geometric principles as a helicopter swash-plate. Instead of cyclically adjusting the propeller blade pitch angle, the relative pitch angle of a fixed pitch propeller is cyclically altered through a pre-swirled inflow generated by an upstream stator row. Wind tunnel and water tunnel experiments were conducted where surface static pressure, forces and moments, and stereoscopic PIV measurements were conducted on a simplified propulsor model. From these measurements a better understanding of the fluidic interactions of the complex propeller system was achieved.

Farnsworth, John; Amitay, Michael; Beal, David; Huyer, Stephen

2010-11-01

219

Loss measurement and analysis for the prototype generator with HTS stator and permanent magnet rotor  

NASA Astrophysics Data System (ADS)

A prototype HTS synchronous generator with a permanent magnet rotor and HTS armature windings was developed. The rated armature frequency is 10 Hz. The cryogenic Dewar is tightly surrounded outside the iron core. Both HTS coils and the iron core were cooled by using conduction cooling method. During the process of no-load running, the no-load loss power data were obtained through the torque measurement. The temperature evolution characteristics of the stator was measured by PT-100 temperature sensors. These results show that the no-load loss power at around 77 K are much larger than that at room temperature. The possible reason for the no-load loss increment is discussed. The ac loss power of one individual HTS coil used in this generator was also tested. Compared with the iron loss power, the ac loss power is rather small and could be neglected.

Song, Peng; Qu, Timing; Yu, Xiaoyu; Li, Longnian; Gu, Chen; Li, Xiaohang; Wang, Dewen; Hu, Boping; Chen, Duxing; Han, Zhenghe

2013-11-01

220

Analysis on accuracy improvement of rotor-stator rubbing localization based on acoustic emission beamforming method.  

PubMed

This paper attempts to introduce an improved acoustic emission (AE) beamforming method to localize rotor-stator rubbing fault in rotating machinery. To investigate the propagation characteristics of acoustic emission signals in casing shell plate of rotating machinery, the plate wave theory is used in a thin plate. A simulation is conducted and its result shows the localization accuracy of beamforming depends on multi-mode, dispersion, velocity and array dimension. In order to reduce the effect of propagation characteristics on the source localization, an AE signal pre-process method is introduced by combining plate wave theory and wavelet packet transform. And the revised localization velocity to reduce effect of array size is presented. The accuracy of rubbing localization based on beamforming and the improved method of present paper are compared by the rubbing test carried on a test table of rotating machinery. The results indicate that the improved method can localize rub fault effectively. PMID:23735348

He, Tian; Xiao, Denghong; Pan, Qiang; Liu, Xiandong; Shan, Yingchun

2013-05-03

221

Flagella stator homologs function as motors for myxobacterial gliding motility by moving in helical trajectories  

PubMed Central

Many bacterial species use gliding motility in natural habitats because external flagella function poorly on hard surfaces. However, the mechanism(s) of gliding remain elusive because surface motility structures are not apparent. Here, we characterized the dynamics of the Myxococcus xanthus gliding motor protein AglR, a homolog of the Escherichia coli flagella stator protein MotA. We observed that AglR decorated a helical structure, and the AglR helices rotated when cells were suspended in liquid or when cells moved on agar surfaces. With photoactivatable localization microscopy, we found that single molecules of AglR, unlike MotA/MotB, can move laterally within the membrane in helical trajectories. AglR slowed down transiently at gliding surfaces, accumulating in clusters. Our work shows that the untethered gliding motors of M. xanthus, by moving within the membrane, can transform helical motion into linear driving forces that push against the surface.

Nan, Beiyan; Bandaria, Jigar N.; Moghtaderi, Amirpasha; Sun, Im-Hong; Yildiz, Ahmet; Zusman, David R.

2013-01-01

222

Gosei resin hatsudenki makisen no zetsuen rekka hanteiho. (Method for diagnosing the insulation deterioration in mica-resin insulated stator windings of generator).  

National Technical Information Service (NTIS)

Any stator windings of generator adopt superior synthetic resin insulation and although old windings are about to arrive at the service life, unified deterioration criterion is not found. In order to establish a deterioration criterion required to diagnos...

1989-01-01

223

A cylindrical shaped micro ultrasonic motor utilizing PZT thin film (1.4 mm in diameter and 5.0 mm long stator transducer)  

Microsoft Academic Search

A cylindrical micro ultrasonic motor utilizing PZT thin film was fabricated and successfully operated on. The dimensions of a stator transducer were 1.4 mm in outer diameter, 1.2 mm in inner diameter, and 5.0 mm in length. This volume is 17% compared to our previous motor (2.4 mm in diameter and 10 mm long stator transducer).To deposit a PZT thin

Takeshi Morita; Minoru Kuribayashi Kurosawa; Toshiro Higuchi

2000-01-01

224

Theoretical modelling, analysis and validation of the shaft motion and dynamic forces during rotor–stator contact  

NASA Astrophysics Data System (ADS)

This paper deals with the theoretical study of a horizontal shaft, partially levitated by a passive magnetic bearing, impacting its stator. Rigid body dynamics are utilised in order to describe the governing nonlinear equations of motion of the shaft interacting with a passive magnetic bearing and stator. Expressions for the restoring magnetic forces are derived using Biot Savart law for uniformed magnetised bar magnets and the contact forces are derived by use of a compliant contact force model. The theoretical mathematical model is verified with experimental results, and shows good agreements. However, the simulated contact forces are higher in magnitude compared to the experimental results. The cause of this disagreement is addressed and shows that the formulation of the theoretical contact force model slightly overestimates the forces acting during a full annular backward whirl motion.

Lahriri, Said; Santos, Ilmar F.

2013-11-01

225

Effect of the hydrodynamic bearing on rotor/stator contact in a ring-type ultrasonic motor.  

PubMed

A hybrid numerical analysis that includes the hydrodynamic bearing effect and elastic contact in a ring-type ultrasonic motor is presented. The two-dimensional time-dependent compressible Reynolds equation is solved numerically by a second-order time accurate, noniterative, factored implicit finite-difference algorithm. The rotor deformation is described by a one-dimensional Green's function. The contact problem is solved by an iteration method so that the contact condition and the hydrodynamic bearing condition are satisfied simultaneously. The results show that the hydrodynamic bearing effect, especially the squeeze effect, is significant for ultrasonic frequency contact of the rotor and stator. Surface roughness, contact area, and normal vibrating speed of the stator are important parameters in the hydrodynamic bearing. A disagreement between the friction coefficient needed in the numerical analysis and the experimentally measured one in a previous study. PMID:18267681

Maeno, T; Bogy, D B

1992-01-01

226

Protection from ground faults in the stator winding of generators at power plants in the Siberian networks  

SciTech Connect

The experience of many years of experience in developing and utilization of ground fault protection in the stator winding of generators in the Siberian networks is generalized. The main method of protection is to apply a direct current or an alternating current with a frequency of 25 Hz to the primary circuits of the stator. A direct current is applied to turbo generators operating in a unit with a transformer without a resistive coupling to the external grid or to other generators. Applying a 25 Hz control current is appropriate for power generation systems with compensation of a capacitive short circuit current to ground. This method forms the basis for protection of generators operating on busbars, hydroelectric generators with a neutral grounded through an arc-suppression reactor, including in consolidated units with generators operating in parallel on a single low-voltage transformer winding.

Vainshtein, R. A., E-mail: vra@tpu.ru [Tomsk Polytechnical University (Russian Federation); Lapin, V. I. [ODU Sibiri (Integrated Dispatcher Control for Siberia), branch of JSC 'SO EES' (Russian Federation); Naumov, A. M.; Doronin, A. V. [JSC NPP 'EKRA' (Russian Federation); Yudin, S. M. [Tomsk Polytechnical University (Russian Federation)

2010-05-15

227

Implementation of a sensorless stator flux oriented asynchronous motor drive with high performances at low-speed operation  

Microsoft Academic Search

A sensorless, stator flux oriented asynchronous motor drive has been realized, by using a low-cost, single chip microcontroller. A motor state observer has been implemented, which showed excellent performances, particularly at low speed operation. Two different experimental realizations have been developed, with rated powers equal to about 1.5 kW and 30 kW respectively, and good results have been obtained in

V. Lovati; M. Marchesoni; M. Oberti; P. Segarich

1996-01-01

228

DSP implementation of the multiple reference frames theory for the diagnosis of stator faults in a DTC induction motor drive  

Microsoft Academic Search

This paper deals with the use of a new diagnostic technique based on the multiple reference frames theory for the diagnosis of stator winding faults in a direct-torque-controlled (DTC) induction motor drive. The theoretical aspects underlying the use of this diagnostic technique are presented but a major emphasis is given to the integration of the diagnostic system into the digital-signal-processor

Sérgio M. A. Cruz; Hamid A. Toliyat; A. J. Marques Cardoso

2005-01-01

229

Research on dual-stator winding multi-phase high-speed induction generator with rectifier load  

Microsoft Academic Search

Based on analysis and calculation of the relation between current harmonics and MMF harmonics in the dual-stator winding multi-phase\\u000a high-speed induction generator with a rectifier load, a new idea, which divides the generator system into two sub-systems\\u000a to be analyzed individually, is presented. For the sub-system of the 12-phase power winding with a rectifier load, the loop\\u000a current method is

XiangHeng Wang; XinZhen Wu

2008-01-01

230

An adaptive Kalman filtering approach to induction machine stator winding temperature estimation based on a hybrid thermal model  

Microsoft Academic Search

The stator winding temperature of an induction machine is estimated from either a thermal model-based or an induction machine parameter-based temperature estimator. The thermal model-based temperature estimator is simple and robust, but it is usually incapable of giving an accurate temperature estimate tailored to a specific motor's thermal capacity. The induction machine parameter-based temperature estimator is accurate and machine-dependent, but

Zhi Gao; Thomas G. Habetler; Ronald G. Harley; Roy S. Colby

2005-01-01

231

Detection of inter-coil short circuits in the stator winding of a PM machine by using saliency tracking schemes  

Microsoft Academic Search

This paper demonstrates the feasibility of using saliency tracking schemes (normally associated with sensorless control of drives) for the detection of inter-coil short circuits in the stator windings of a PM machine. This is obtained through a co-simulating of Matlab\\/Simulink and a Finite Element Model (FEM). Vector control and sensorless control schemes based on saliency tracking were implemented using Simulink,

J. Arellano-Padilla; M. Sumner; C. Gerada; G. Buckley

2011-01-01

232

Direct Torque Control with Full Order Stator Flux Observer for Dual-Three Phase Induction Motor Drives  

NASA Astrophysics Data System (ADS)

A Direct Torque Control (DTC) strategy for dual-three phase induction motor drives is discussed in this paper. The induction machine has two sets of stator three-phase windings spatially shifted by 30 electrical degrees with isolated neutral points. The proposed control strategy is based on Proportional Integral (PI) regulators implemented in the stator flux synchronous reference frame. To improve the flux estimation, an Adaptive Stator Flux Observer (ASFO) has been used. Doing so, besides a better flux estimation in contrast to open-loop flux estimators, it is possible to use the observed currents to compensate the inverter non-linear behavior (such as dead-time effects), improving the drive performance at low speed. This is particularly important for low voltage/high current applications, as the drive considered in this paper. The advantages of the discussed control strategy are: constant inverter switching frequency, good transient and steady-state performance and less distorted machine currents in contrast to DTC schemes with variable switching frequency. Experimental results are presented for a 10kW dual three-phase induction motor drive prototype.

Farina, Francesco; Bojoi, Radu; Tenconi, Alberto; Profumo, Francesco

233

Compressible simulation of rotor-stator interaction in pump-turbines  

NASA Astrophysics Data System (ADS)

This work investigates the influence of water compressibility on pressure pulsations induced by rotor-stator interaction (RSI) in hydraulic machinery, using the commercial CFD solver ANSYS-CFX. A pipe flow example with harmonic velocity excitation at the inlet plane is simulated using different grid densities and time step sizes. Results are compared with a validated code for hydraulic networks (SIMSEN). Subsequently, the solution procedure is applied to a simplified 2.5-dimensional pump-turbine configuration in model scale with an adapted speed of sound. Pressure fluctuations are compared with numerical and experimental data based on prototype scale. The good agreement indicates that the scaling of acoustic effects with an adapted speed of sound works well. Finally, the procedure is applied to a 3-dimensional pump configuration in model scale. Pressure fluctuations are compared with results from prototype measurements. Compared to incompressible computations, compressible simulations provide similar pressure fluctuations in vaneless space, but pressure fluctuations in spiral case and penstock may be much higher. With respect to pressure fluctuation amplitudes along the centerline of runner channels, incompressible solutions exhibit a linear decrease while compressible solutions exhibit sinusoidal distributions with maximum values at half the channel length, coinciding with analytical solutions of one-dimensional acoustics.

Yan, J.; Koutnik, J.; Seidel, U.; Hübner, B.

2010-08-01

234

PIV measurements of an air jet impinging on an open rotor-stator system  

NASA Astrophysics Data System (ADS)

The current work experimentally investigates the flow characteristics of an air jet impinging on an open rotor-stator system with a low non-dimensional spacing, G = 0.02, and with a very low aspect ratio, e/ D = 0.25. The rotational Reynolds numbers varied from 0.33×10^5 to 5.32×10^5, while the jet Reynolds numbers ranged from 17.2 × 103 to 43 × 103. Particle image velocimetry (PIV) measurements were taken along the entire disk diameter in three axial planes. From the obtained PIV velocity fields, the flow statistics were computed. A recirculation flow region, which was centered at the impingement point and possessed high turbulence intensities, was observed. Local peaks in root-mean-square fluctuating velocity distributions appeared in the recirculation region and near the periphery, respectively. Proper orthogonal decomposition analysis was applied to the cases of the jet impinging on the rotor with and without rotation to reveal the coherent structures in the jet region.

Nguyen, T. D.; Pellé, J.; Harmand, S.; Poncet, S.

2012-08-01

235

Numerical simulation of sand erosion phenomena in rotor/stator interaction of compressor  

NASA Astrophysics Data System (ADS)

Sand erosion is a phenomenon where solid particles impinging to a wall cause serious mechanical damages to the wall surface. This phenomenon is a typical gas-particle two-phase turbulent flow and a multi-physics problem where the flow field, particle trajectory and wall deformation interact with each other. On the other hand, aircraft engines operating in a particulate environment are subjected to the performance and lifetime deterioration due to sand erosion. Especially, the compressor of the aircraft engines is severely damaged. The flow fields of the compressor have strongly three dimensional and unsteady natures. In order to estimate the deterioration due to sand erosion, the sand erosion simulation for a compressor is required under the consideration of the rotor-stator interaction. In the present study, we apply our three dimensional sand erosion prediction code to a single stage axial flow compressor. We numerically investigate the change of the flow field, the particle trajectories, and the eroded wall shape in the compressor, to clarify the effects of sand erosion in the compressor.

Suzuki, Masaya; Inaba, Kazuaki; Yamamoto, Makoto

2008-06-01

236

EVALUACION CRITICA DEL TEST DE TOLERANCIA ORAL A LA GLUCOSA PARA EL DIAGNOSTICO DE RESISTENCIA INSULINICA EN PACIENTES CON SINDROME DE OVARIO POLIQUISTICO  

Microsoft Academic Search

Palabras clave: síndrome de ovario poliquístico, resistencia insulínica, test de tolerancia a la glucosa Abstract Critical evaluation of the oral glucose tolerance test for the diagnosis of insulin resistance in patients with polycystic ovary syndrome. Oral glucose tolerance test (OGTT) is the most commonly used method to evaluate insulin resistance (IR) in the clinical practice. Our objective was to evaluate

CECILIA E. CALVAR; SONIA V. BENGOLEA; RICARDO HERMES; MARCELO LOYATO; Servicio de Endocrinología; J. A. Fernández

237

Rotor-stator contact dynamics using a non-ideal drive—Theoretical and experimental aspects  

NASA Astrophysics Data System (ADS)

The possible contact between rotor and stator is considered a serious malfunction that may lead to catastrophic failure. Rotor rub is seen as a secondary phenomenon caused by a primary source, i.e. sudden mass unbalance, instabilities generated by aerodynamic and hydrodynamic forces in seals and bearings among others. The contact event gives rise to normal and friction forces exerted on the rotor at impact events. The friction force plays a significant role by transferring some rotational energy of the rotor to lateral motion. A mathematical model has been developed to capture this for a conventional backup annular guide setup. It is reasonable to superpose an impact condition to the rub, where the rotor spin energy can be fully transformed into rotor lateral movements. Using a nonideal drive, i.e. an electric motor without any kind of velocity feedback control, it is even possible to stop the rotor spin under rubbing conditions. All the rotational energy will be transformed in a kind of “self-excited” rotor lateral vibration with repeated impacts against the housing. This paper studies the impact motion of a rotor impacting a conventional backup annular guide for the case of dry and lubricated inner surface of the guide. For the dry surface case, the experimental and numerical analysis shows that the rotational energy is fully transformed into lateral motion and the rotor spin is stopped. Based on this study this paper proposes a new unconventional backup bearing design in order to reduce the rub related severity in friction and center the rotor at impact events. The analysis shows that the rotor at impacts is forced to the center of the backup bearing and the lateral motion is mitigated. As a result of this, the rotor spin is kept constant.

Lahriri, Said; Weber, Hans I.; Santos, Ilmar F.; Hartmann, Henning

2012-09-01

238

On-line monitoring of partial discharges on stator winding of large rotating machines in the petrochemical environment  

SciTech Connect

This paper describes a joint collaboration program between a major large machine manufacturer and a petrochemical manufacturer to investigate the effectiveness of time- and frequency-domain techniques for on-line monitoring of the health of high-voltage machine stator insulation systems. Information is given on the factory and site testing carried out, as well as on the analysis and discussion of the results. It is concluded that both techniques can be used in the petrochemical environment for general assessments, but the time-domain technique is required if identification of specific locations of discharge sites is needed.

Bethge, A. [Siemens AG, Berlin (Germany); Lo, P.K.W. [Imperial Oil Ltd., Sarnia, Ontario (Canada). Products and Chemical Div.; Phillipson, J.T. [Exxon Chemical Co., Southampton (United Kingdom); Weidner, J.R. [Siemens AG, Muelheim (Germany)

1998-11-01

239

Influence of the rotor-stator interaction on the dynamic stresses of Francis runners  

NASA Astrophysics Data System (ADS)

Thanks to advances in computing capabilities and Computational Fluid Dynamics (CFD) techniques, it is now possible to calculate realistic unsteady pressure fields in Francis turbines. This paper will explain methods to calculate the structural loads and the dynamic behaviour in order to optimize the turbine design and maximize its reliability and lifetime. Depending on the operating conditions of a Francis turbine, different hydraulic phenomena may impact the mechanical behaviour of the structure. According to their nature, these highly variable phenomena should be treated differently and specifically in order to estimate the potential risks arising on submerged structures, in particular the runner. The operating condition studied thereafter is the point at maximum power with the maximum head. Under this condition, the runner is excited by only one dynamic phenomenon named the Rotor-Stator Interaction (RSI). The origin of the phenomenon is located on the radial gap of the turbine and is the source of pressure fluctuations. A fluid-structure analysis is performed to observe the influence of that dynamic pressure field on the runner behaviour. The first part of the paper deals with the unsteady fluid computation. The RSI phenomenon is totally unsteady so the fluid simulation must take into account the entire machine and its rotation movement, in order to obtain a dynamic pressure field. In the second part of the paper, a method suitable for the RSI study is developed. It is known that the fluctuating pressure in this gap can be described as a sum of spatial components. By evaluating these components in the CFD results and on the scale model, it is possible to assess the relevance of the numerical results on the whole runner. After this step, the numerical pressure field can be used as the dynamic load of the structure. The final part of the paper presentsthe mechanical finite element calculations. A modal analysis of the runner in water and a harmonic analysis of its dynamic behaviour using the CFD results are carried out. These calculations will show that the RSI on the medium head Francis runner does not create damage on the runner even if the natural frequencies are closed to the wicket gates passing frequency. The numerical results are reinforced by experimental observations done on runner prototypes showing that the wicket gates passing frequency does not have significant influence on low and medium head Francis runner behaviour.

Guillaume, R.; Deniau, J. L.; Scolaro, D.; Colombet, C.

2012-11-01

240

Intragenic Suppressor of a Plug Deletion Nonmotility Mutation in PotB, a Chimeric Stator Protein of Sodium-Driven Flagella  

PubMed Central

The torque of bacterial flagellar motors is generated by interactions between the rotor and the stator and is coupled to the influx of H+ or Na+ through the stator. A chimeric protein, PotB, in which the N-terminal region of Vibrio alginolyticus PomB was fused to the C-terminal region of Escherichia coli MotB, can function with PomA as a Na+-driven stator in E. coli. Here, we constructed a deletion variant of PotB (with a deletion of residues 41 to 91 [?41–91], called PotB?L), which lacks the periplasmic linker region including the segment that works as a “plug” to inhibit premature ion influx. This variant did not confer motile ability, but we isolated a Na+-driven, spontaneous suppressor mutant, which has a point mutation (R109P) in the MotB/PomB-specific ?-helix that connects the transmembrane and peptidoglycan binding domains of PotB?L in the region of MotB. Overproduction of the PomA/PotB?L(R109P) stator inhibited the growth of E. coli cells, suggesting that this stator has high Na+-conducting activity. Mutational analyses of Arg109 and nearby residues suggest that the structural alteration in this ?-helix optimizes PotB?L conformation and restores the proper arrangement of transmembrane helices to form a functional channel pore. We speculate that this ?-helix plays a key role in assembly-coupled stator activation.

Zhu, Shiwei

2012-01-01

241

Roles of charged residues of rotor and stator in flagellar rotation: comparative study using H+-driven and Na+-driven motors in Escherichia coli.  

PubMed

In Escherichia coli, rotation of the flagellar motor has been shown to depend upon electrostatic interactions between charged residues of the stator protein MotA and the rotor protein FliG. These charged residues are conserved in the Na+-driven polar flagellum of Vibrio alginolyticus, but mutational studies in V. alginolyticus suggested that they are relatively unimportant for motor rotation. The electrostatic interactions detected in E. coli therefore might not be a general feature of flagellar motors, or, alternatively, the V. alginolyticus motor might rely on similar interactions but incorporate additional features that make it more robust against mutation. Here, we have carried out a comparative study of chimeric motors that were resident in E. coli but engineered to use V. alginolyticus stator components, rotor components, or both. Charged residues in the V. alginolyticus rotor and stator proteins were found to be essential for motor rotation when the proteins functioned in the setting of the E. coli motor. Patterns of synergism and suppression in rotor/stator double mutants indicate that the V. alginolyticus proteins interact in essentially the same way as their counterparts in E. coli. The robustness of the rotor-stator interface in V. alginolyticus is in part due to the presence of additional charged residues in PomA but appears mainly due to other factors, because an E. coli motor using both rotor and stator components from V. alginolyticus remained sensitive to mutation. Motor function in V. alginolyticus may be enhanced by the proteins MotX and MotY. PMID:16452430

Yakushi, Toshiharu; Yang, Junghoon; Fukuoka, Hajime; Homma, Michio; Blair, David F

2006-02-01

242

Prototype and estimation an ultrasonic motor using a transmission rod with a stator vibrator and a rotor at the both ends  

NASA Astrophysics Data System (ADS)

A new structure of ultrasonic motor composed of a stator vibrator, a rotor and an ultrasonic transmission rod is proposed. Two vibrations of a stator vibrator mounted at a rod end excite two orthogonal bending vibrations in the rod and elliptic motions of displacement are formed at another end of the rod. The elliptic motions produce a rotating force to a rotor pressed at the end. The simple structure of mounting and preloading a rotor is designed by FEM. It is checked experimentally that two orthogonal bending vibrations are excited in the rod and the motor operation of the new construction is confirmed.

Takano, Takehiro; Tamura, Hideki; Sato, Daisuke; Aoyagi, Manabu

2012-05-01

243

Non bonded interaction between BnNn (stator) and BNB (rotor) systems: A quantum rotation in IR region  

NASA Astrophysics Data System (ADS)

The electromagnetic non-bonded interactions of BNB molecule as a quantum rotor inside several of BnNn molecular rings as a stator has been investigated by using EPR-II and EPR-III basis sets. Optimized structures, relative stability and hyperfine spectroscopic parameters, have been calculated. In this study, we have shown that the BnNn-BNB systems can be works as a nano rotor-stator molecular motor for the biological systems. Although in our previous works, we have discussed (Monajjemi et al. (2010) [20] and Monajjemi and Boggs (2013) [18]) of the stability and electromagnetic properties of some kind of BnNn rings, using of these systems as a detector are much more significant and have investigated in this work. The study for the BnNn-BNB systems and then for Adenine-Thymine and Guanine-Cytosine base pairs coupled with BNB inside the BnNn (n = 8, 12, 15, 16, 18, 20, 24) have been investigated. Three quantized rotational frequencies in cationic, radical, and anionic forms have been calculated and all frequencies appeared in the IR rotational region.

Monajjemi, Majid

2013-11-01

244

Investigation of an on-line rotor resistance identification with a new stator resistance observer for induction motor drive using artificial neural networks  

Microsoft Academic Search

This paper presents a new method of on-line estimation for the stator and rotor resistances of the induction motor in the indirect vector controlled drive, using artificial neural networks. The back propagation algorithm is used for training of the neural networks. The error between the desired state variable of an induction motor and the actual state variable of a neural

B. Karanayil; M. F. Rahman; C. Grantham

2003-01-01

245

On-line rotor resistance identification for induction motor drive with artificial neural networks supported by a simple PI stator resistance estimator  

Microsoft Academic Search

This paper presents a new method of on-line estimation for the rotor and stator resistances of the induction motor in the indirect vector controlled drive, using artificial neural networks and a simple PI compensator. The back propagation algorithm is used for the training of the neural networks for rotor resistance identification. The error between the desired state variable of an

B. Karanayil; M. F. Rahman; C. Grantharn

2003-01-01

246

A novel on-line MRAS rotor resistance identification method insensitive to stator resistance for vector control systems of induction machines  

Microsoft Academic Search

On-line identification and correction of the rotor resistance is essential for improving the static and the dynamic performances of the vector control systems of induction machines. In this paper, a novel MRAS algorithm on-line identifying the rotor resistance, which is completely free from the effects of the stator resistance, is developed. Both the reference model and the adjustable model do

Jie Li; Haipeng Ren; Qifu Huang; Yanru Zhong

2010-01-01

247

Speed sensorless stator flux oriented control of three-level inverter-fed induction motor drive based on fuzzy logic and sliding mode control  

Microsoft Academic Search

A novel simplified stator flux oriented control (SFOC) for three-level inverter-fed induction motor drive is proposed to achieve high performance torque control in both steady state and transient conditions. Sliding mode control (SMC) is designed, in stead of conventional PI controller, to obtain the continuous commanding voltage vectors. The speed accuracy and dynamic tracking performance, as well as robustness to

Yongchang Zhang; Jianguo Zhu; Wei Xu; Jiefeng Hu; David G. Dorrell; Zhengming Zhao

2010-01-01

248

Rotor power losses in planar radial magnetic bearings -- Effects of number of stator poles, air gas thickness, and magnetic flux density  

Microsoft Academic Search

Rotor power losses in magnetic bearings cannot be accurately calculated at this time because of the complexity of the magnetic field distribution and several other effects. The losses are due to eddy currents, hysteresis, and windage. This paper presents measured results in radial magnetic bearing configurations with eight pole and 16 pole stators and two laminated rotors. Two different air

P. E. Allaire; M. E. F. Kasarda; L. K. Fujita

1999-01-01

249

Performance of a fractional dc electric motor equipped with plastic bonded Nd{sub 2}Fe{sub 14}B stator poles  

SciTech Connect

Injection molding Nd{sub 2}Fe{sub 14}B plastic bonded magnetic material is pressed into the form of cylindrical ring segments in order to investigate its performance when used in the manufacturing of stator poles of fractional power dc motors. Measurements of speed and armature current versus different load torques were performed. The experimental results obtained for stator poles made by three plastic bonded Nd{sub 2}Fe{sub 14}B magnetic materials of different densities, are compared to those results obtained by using a pair of typical barium ferrite stator poles. The torque versus speed curves, the obtained mechanical power versus speed and the efficiency of the motor as a function of the speed are presented. The torque speed data in high speeds follow a linear law, as is expected by theory, while at low speeds, below a crossover point, a deviation from this linearity appears. This is attributed to temperature effects. In this work it is shown that in the region of light loads and high speeds, at a certain speed, the injection molded Nd{sub 2}Fe{sub 14}B permanent magnet stators produce a higher electromagnetic torque, higher mechanical power, and higher efficiency than the barium ferrite ones. {copyright} {ital 1997 American Institute of Physics.}

Nicolaides, G.K.; Atanassova, Y.K. [Department of Physics--Chemistry and Technology of Materials, Technological Education Institute of Piraeus, P. Ralli Thivon 250, Aegaleo 122 44 (Greece); Ioannides, M.G.; Tsamakis, D.M. [Department of Electrical and Computer Engineering, National Technical University of Athens, Iroon Polytechniou 9, Zografou 15773 (Greece); Gamari-Seale, H. [NCSR Demokritos, IMS, Aghia Paraskevi 15310 (Greece)

1997-04-01

250

Design and analysis of a five-phase interior permanent magnet generator with a non-integer number of stator slots per phase  

Microsoft Academic Search

Traditional electric machine design requiring the balancing of the phases both in phase voltage magnitudes and the angles between adjacent phases informs that the number of stator slots per phase must be an integer. There are situations however, where it is cheaper to use existing laminations for designs with non-integer number of slots per phase to build generators for specialized

Olorunfemi Ojo; Zhiqiao Wu; Sosthenes Karugaba; Adeola Balogun; Emeka Obe

2009-01-01

251

Surface Temperature Measurements from a Stator Vane Doublet in a Turbine Engine Afterburner Flame using Ultra-Bright Cr-Doped GdAlO3 Thermographic Phosphor.  

National Technical Information Service (NTIS)

Luminescence-based surface temperature measurements from an ultra-bright Cr-doped GdAlO3 perovskite (GAP:Cr) coating were successfully conducted on an air-film-cooled stator vane doublet exposed to the afterburner flame of a J85 test engine at University ...

D. E. Wolfe J. I. Eldridge R. P. Howard S. W. Allison T. P. Jenkins

2013-01-01

252

Design and testing of swept and leaned outlet guide vanes to reduce stator-strut-splitter aerodynamic flow interactions  

SciTech Connect

Large circumferentially varying pressure levels produced by aerodynamic flow interactions between downstream stators and struts present a potential noise and stability margin liability in a compression component. These interactions are presently controlled by tailoring the camber and/or stagger angles of vanes neighboring the fan frame struts. This paper reports on the design and testing of a unique set of swept and leaned fan outlet guide vanes (OGVs) that do not require this local tailoring even though the OGVs are closely coupled with the fan frame struts and splitter to reduce engine length. The swept and leaned OGVs not only reduce core-duct diffusion, but they also reduce the potential flow interaction between the stator and the strut relative to that produced by conventional radial OGVs. First, the design of the outlet guide vanes using a single blade row three-dimensional viscous flow analysis is outlined. Next, a two-dimensional potential flow analysis was used for the coupled OGV-frame system to obtain a circumferentially nonuniform stator stagger angle distribution to reduce the upstream static pressure disturbance further. Recognizing the limitations of the two-dimensional potential flow analysis for this highly three-dimensional set of leaned OGVs, as a final evaluation of the OGV-strut system design, a full three-dimensional viscous analysis of a periodic circumferential sector of the OGVs, including the fan frame struts and splitter, was performed. The computer model was derived from a NASA-developed code used in simulating the flow field for external aerodynamic applications with complex geometries. The tree-dimensional coupled OGV-frame analysis included the uniformly staggered OGV configuration and the variably staggered OGV configuration determined by the two-dimensional potential flow analysis. Contrary to the two-dimensional calculations, the tree-dimensional analysis revealed significant flow problems with the variable staggered OGV configuration and showed less upstream flow nonuniformity with the uniformly staggered OGV configuration. The flow redistribution in both the radial and tangential directions, captured fully only in the three-dimensional analysis, was identified as the prime contributor to the lower flow nonuniformity with the uniformly staggered OGV configuration. The coupled three-dimensional analysis was also used to validate the design at off-design conditions. Engine test performance and stability measurements with both uniformly and variably staggered OGV configurations with and without the presence of inlet distortion confirmed the conclusions from the three-dimensional analysis.

Wadia, A.R.; Szucs, P.N. [GE Aircraft Engines, Cincinnati, OH (United States); Gundy-Burlet, K.L. [NASA Ames Research Center, Moffet Field, CA (United States)

1999-07-01

253

Intact Flagellar Motor of Borrelia burgdorferi Revealed by Cryo-Electron Tomography: Evidence for Stator Ring Curvature and Rotor/C-Ring Assembly Flexion? †  

PubMed Central

The bacterial flagellar motor is a remarkable nanomachine that provides motility through flagellar rotation. Prior structural studies have revealed the stunning complexity of the purified rotor and C-ring assemblies from flagellar motors. In this study, we used high-throughput cryo-electron tomography and image analysis of intact Borrelia burgdorferi to produce a three-dimensional (3-D) model of the in situ flagellar motor without imposing rotational symmetry. Structural details of B. burgdorferi, including a layer of outer surface proteins, were clearly visible in the resulting 3-D reconstructions. By averaging the 3-D images of ?1,280 flagellar motors, a ?3.5-nm-resolution model of the stator and rotor structures was obtained. flgI transposon mutants lacked a torus-shaped structure attached to the flagellar rod, establishing the structural location of the spirochetal P ring. Treatment of intact organisms with the nonionic detergent NP-40 resulted in dissolution of the outermost portion of the motor structure and the C ring, providing insight into the in situ arrangement of the stator and rotor structures. Structural elements associated with the stator followed the curvature of the cytoplasmic membrane. The rotor and the C ring also exhibited angular flexion, resulting in a slight narrowing of both structures in the direction perpendicular to the cell axis. These results indicate an inherent flexibility in the rotor-stator interaction. The FliG switching and energizing component likely provides much of the flexibility needed to maintain the interaction between the curved stator and the relatively symmetrical rotor/C-ring assembly during flagellar rotation.

Liu, Jun; Lin, Tao; Botkin, Douglas J.; McCrum, Erin; Winkler, Hanspeter; Norris, Steven J.

2009-01-01

254

Intact flagellar motor of Borrelia burgdorferi revealed by cryo-electron tomography: evidence for stator ring curvature and rotor/C-ring assembly flexion.  

PubMed

The bacterial flagellar motor is a remarkable nanomachine that provides motility through flagellar rotation. Prior structural studies have revealed the stunning complexity of the purified rotor and C-ring assemblies from flagellar motors. In this study, we used high-throughput cryo-electron tomography and image analysis of intact Borrelia burgdorferi to produce a three-dimensional (3-D) model of the in situ flagellar motor without imposing rotational symmetry. Structural details of B. burgdorferi, including a layer of outer surface proteins, were clearly visible in the resulting 3-D reconstructions. By averaging the 3-D images of approximately 1,280 flagellar motors, a approximately 3.5-nm-resolution model of the stator and rotor structures was obtained. flgI transposon mutants lacked a torus-shaped structure attached to the flagellar rod, establishing the structural location of the spirochetal P ring. Treatment of intact organisms with the nonionic detergent NP-40 resulted in dissolution of the outermost portion of the motor structure and the C ring, providing insight into the in situ arrangement of the stator and rotor structures. Structural elements associated with the stator followed the curvature of the cytoplasmic membrane. The rotor and the C ring also exhibited angular flexion, resulting in a slight narrowing of both structures in the direction perpendicular to the cell axis. These results indicate an inherent flexibility in the rotor-stator interaction. The FliG switching and energizing component likely provides much of the flexibility needed to maintain the interaction between the curved stator and the relatively symmetrical rotor/C-ring assembly during flagellar rotation. PMID:19429612

Liu, Jun; Lin, Tao; Botkin, Douglas J; McCrum, Erin; Winkler, Hanspeter; Norris, Steven J

2009-05-08

255

Lattice dynamics of a rotor-stator molecular crystal: Fullerene-cubane C60?C8H8  

NASA Astrophysics Data System (ADS)

The dynamics of fullerene-cubane (C60?C8H8) cocrystal is studied combining experimental [x-ray diffuse scattering, quasielastic and inelastic neutron scattering (INS)] and simulation (molecular dynamics) investigations. Neutron scattering gives direct evidence of the free rotation of fullerenes and of the libration of cubanes in the high-temperature phase, validating the “rotor-stator” description of this molecular system. X-ray diffuse scattering shows that orientational disorder survives the order/disorder transition in the low-temperature phase, although the loss of fullerene isotropic rotational diffusion is featured by the appearance of a 2.2 meV mode in the INS spectra. The coupling between INS and simulations allows identifying a degeneracy lift of the cubane librations in the low temperature phase, which is used as a tool for probing the environment of cubane in this phase and for getting further insights into the phase transition mechanism.

Bousige, Colin; Rols, Stéphane; Cambedouzou, Julien; Verberck, Bart; Pekker, Sándor; Kováts, Éva; Durkó, Gábor; Jalsovsky, István; Pellegrini, Éric; Launois, Pascale

2010-11-01

256

Lateral and Torsional Vibrations of a Two-disk Rotor-stator System with Axial Contact/Rubs  

NASA Astrophysics Data System (ADS)

The dynamics of a rotor system with axial contact/rub events between the disks and stator are investigated by numerical simulations. The coupled equations of lateral and torsional motions of rotor and the lateral motion of disk are established. Numerical simulations are carried out to reveal the lateral and torsional vibrations for both two-disk contact/rubs and one disk contact/rubs. Bifurcation diagrams, orbits, phase portraits, amplitude- frequency spectra and Poincaré maps are adopted to demonstrate the dynamical behaviors of the system. The results show that though both the lateral and torsional vibrations can reflect the influences of contact/rubs on rotor dynamics, the spectrum analyses of the torsional vibrations are more suitable to determine straight the extent of their effect.

Ding, Qian; Zhang, Kunpeng

2010-05-01

257

Atlas del Genoma del Cáncer  

Cancer.gov

El Atlas del Genoma del Cáncer es una iniciativa de los Institutos Nacionales de la Salud (NIH) para crear mapas multidimensionales completos de los cambios genómicos clave en los tipos y subtipos principales de cáncer.

258

Vibrational spectra of C60.C8H8 and C70.C8H8 in the rotor-stator and polymer phases.  

PubMed

C(60).C(8)H(8) and C(70).C(8)H(8) are prototypes of rotor-stator cocrystals. We present infrared and Raman spectra of these materials and show how the rotor-stator nature is reflected in their vibrational properties. We measured the vibrational spectra of the polymer phases poly(C(60)C(8)H(8)) and poly(C(70)C(8)H(8)) resulting from a solid-state reaction occurring on heating. On the basis of the spectra, we propose a connection pattern for the fullerene in poly(C(60)C(8)H(8)), where the symmetry of the C(60) molecule is D(2h). On illuminating the C(60).C(8)H(8) cocrystal with green or blue light, a photochemical reaction was observed leading to a product similar to that of the thermal polymerization. PMID:17918992

Klupp, G; Borondics, F; Kováts, E; Pekker, A; Bényei, G; Jalsovszky, I; Hackl, R; Pekker, S; Kamarás, K

2007-10-06

259

Rotor/Stator interactions of the epsilon subunit in Escherichia coli ATP synthase and implications for enzyme regulation.  

PubMed

The H(+)-translocating F(0)F(1)-ATP synthase of Escherichia coli functions as a rotary motor, coupling the transmembrane movement of protons through F(0) to the synthesis of ATP by F(1). Although the epsilon subunit appears to be tightly associated with the gamma subunit in the central stalk region of the rotor assembly, several studies suggest that the C-terminal domain of epsilon can undergo significant conformational change as part of a regulatory process. Here we use disulfide cross-linking of substituted cysteines on functionally coupled ATP synthase to characterize interactions of epsilon with an F(0) component of the rotor (subunit c) and with an F(1) component of the stator (subunit beta). Oxidation of the engineered F(0)F(1) causes formation of two disulfide bonds, betaD380C-S108C epsilon and epsilonE31C-cQ42C, to give a beta-epsilon-c cross-linked product in high yield. The results demonstrate the ability of epsilon to span the central stalk region from the surface of the membrane (epsilon-c) to the bottom of F(1) (beta-epsilon) and suggest that the conformation detected here is distinct from both the "closed" state seen with isolated epsilon (Uhlin, U., Cox, G. B., and Guss, J. M. (1997) Structure 5, 1219-1230) and the "open" state seen in a complex with a truncated form of the gamma subunit (Rodgers, A. J., and Wilce, M. C. (2000) Nat. Struct. Biol. 7, 1051-1054). The kinetics of beta-epsilon and epsilon-c cross-linking were studied separately using F(0)F(1) containing one or the other matched cysteine pair. The rate of cross-linking at the epsilon/c (rotor/rotor) interface is not influenced by the type of nucleotide added. In contrast, the rate of beta-epsilon cross-linking is fastest under ATP hydrolysis conditions, intermediate with MgADP, and slowest with MgAMP-PNP. This is consistent with a regulatory role for a reversible beta/epsilon (stator/rotor) interaction that blocks rotation and inhibits catalysis. Furthermore, the rate of beta-epsilon cross-linking is much faster than that indicated by previous studies, allowing for the possibility of a rapid response to regulatory signals. PMID:15199054

Bulygin, Vladimir V; Duncan, Thomas M; Cross, Richard L

2004-06-15

260

Diagnosis of stator, rotor and airgap eccentricity faults in three-phase induction motors based on the multiple reference frames theory  

Microsoft Academic Search

This paper describes the use of multiple reference frames for the diagnosis of stator, rotor, and eccentricity faults in line-fed and direct torque controlled (DTC) inverter-fed induction motors. The use of this new technique, which was proposed by the authors for the diagnosis of inter-turn short circuits, is extended for the detection and classification of different types of faults. Each

S. M. A. Cruz; A. J. M. Cardoso; H. A. Toliyat

2003-01-01

261

Direct Torque Control of an IPM-Synchronous Motor Drive at Very Low Speed Using a Sliding-Mode Stator Flux Observer  

Microsoft Academic Search

Direct torque control of interior permanent-magnet synchronous motors is known to deliver fast torque and flux dynamic responses. However, the poor flux estimation at very low speeds has been its largest drawback. A multitude of flux observers have been proposed for flux estimation, but most of them fail to fare in the low-speed region. This paper proposes a sliding-mode stator

Gilbert Hock Beng Foo; M. F. Rahman

2010-01-01

262

The effects of various magnetic materials on lamination design for stator-rotor diecasting of induction motors for electric vehicle applications  

SciTech Connect

In this paper the authors describe a novel technique to model induction motors with a diecast stator and rotor and to examine the effects of various magnetic materials on the electrical performance of the motor. For electric vehicle applications, a high volume production operation of the electric motor requires the motor to be small and inexpensive. The expensive labor and material used to manufacture the motor encouraged the researchers to find new methods and techniques to reduce the cost and improve the performance. Diecast rotor and stator windings reduce motor cost and size. For diecasting induction motors, the motor laminations should be designed to optimize the electromagnetic field distribution over the cross section and along the axial direction. The magnetic material used for the laminations should also reduce losses and improve the overall efficiency. A 100 hp four-pole induction motor was modeled with finite elements, and the field distribution, the magnetic flux density, and the mechanical performance of the motor were computed using nonlinear magnetostatic and complex steady-state eddy current techniques. The difference in the electrical and mechanical performance of the motor were evaluated for copper and aluminum diecasting. The results show that copper diecasting of the rotor and the stator of the induction motor with magnetic material properties and identified slotting shape is the way to achieve better motor performance and low cost operation. 5 refs.

Elkasabgy, N.M.; Di Pietro, C. [Westinghouse Motor Co. Ltd., Hamilton, Ontario (Canada)

1994-05-15

263

Torque Generation in F1-ATPase Devoid of the Entire Amino-Terminal Helix of the Rotor That Fills Half of the Stator Orifice  

PubMed Central

F1-ATPase is an ATP-driven rotary molecular motor in which the central ?-subunit rotates inside a cylinder made of ?3?3 subunits. The amino and carboxyl termini of the ? rotor form a coiled coil of ?-helices that penetrates the stator cylinder to serve as an axle. Crystal structures indicate that the axle is supported by the stator at two positions, at the orifice and by the hydrophobic sleeve surrounding the axle tip. The sleeve contacts are almost exclusively to the longer carboxyl-terminal helix, whereas nearly half the orifice contacts are to the amino-terminal helix. Here, we truncated the amino-terminal helix stepwise up to 50 residues, removing one half of the axle all the way up and far beyond the orifice. The half-sliced axle still rotated with an unloaded speed a quarter of the wild-type speed, with torque nearly half the wild-type torque. The truncations were made in a construct where the rotor tip was connected to a ?-subunit via a short peptide linker. Linking alone did not change the rotational characteristics significantly. These and previous results show that nearly half the normal torque is generated if rotor-stator interactions either at the orifice or at the sleeve are preserved, suggesting that the make of the motor is quite robust.

Kohori, Ayako; Chiwata, Ryohei; Hossain, Mohammad Delawar; Furuike, Shou; Shiroguchi, Katsuyuki; Adachi, Kengo; Yoshida, Masasuke; Kinosita, Kazuhiko

2011-01-01

264

Combined effects of axial- and radial-gap spacing of the mass transfer characteristics of a shrouded rotor-stator system  

NASA Astrophysics Data System (ADS)

Heat transfer characteristics of a shrouded rotor-stator system are examined using a mass transfer analog technique. Both local and average mass-transfer coefficients for a naphthalene-coated disk rotating in a quiescent environment are obtained for Re between values of 4.0 x 10 exp 4 and 2.4 x 10 exp 5. The measured results, which correlate well with theoretical predictions, are used to evaluate the influence of radial-gap clearance and axial-gap spacing on average and local mass-transfer rates in a shrouded rotor-stator with no superposed coolant flow. Similar to a rotor-stator system without a shroud, a reduction in the axial gap tends to decrease the average mass transfer, with the magnitude of the decrease being inversely proportional to the Reynolds number. Such a reduction in mass transfer is also found to be influenced by the radial clearance gap. A reduction of the radial clearance from a/D = 0.042 to 0.020 is shown to decrease the average Sherwood number by approximately 20 percent of the corresponding free disk value. Local mass transfer distributions illustrate a more significant axial gap effect.

Chyu, M. K.; Bizzak, D. J.

1991-06-01

265

Torque generation in F1-ATPase devoid of the entire amino-terminal helix of the rotor that fills half of the stator orifice.  

PubMed

F(1)-ATPase is an ATP-driven rotary molecular motor in which the central ?-subunit rotates inside a cylinder made of ?(3)?(3) subunits. The amino and carboxyl termini of the ? rotor form a coiled coil of ?-helices that penetrates the stator cylinder to serve as an axle. Crystal structures indicate that the axle is supported by the stator at two positions, at the orifice and by the hydrophobic sleeve surrounding the axle tip. The sleeve contacts are almost exclusively to the longer carboxyl-terminal helix, whereas nearly half the orifice contacts are to the amino-terminal helix. Here, we truncated the amino-terminal helix stepwise up to 50 residues, removing one half of the axle all the way up and far beyond the orifice. The half-sliced axle still rotated with an unloaded speed a quarter of the wild-type speed, with torque nearly half the wild-type torque. The truncations were made in a construct where the rotor tip was connected to a ?-subunit via a short peptide linker. Linking alone did not change the rotational characteristics significantly. These and previous results show that nearly half the normal torque is generated if rotor-stator interactions either at the orifice or at the sleeve are preserved, suggesting that the make of the motor is quite robust. PMID:21723829

Kohori, Ayako; Chiwata, Ryohei; Hossain, Mohammad Delawar; Furuike, Shou; Shiroguchi, Katsuyuki; Adachi, Kengo; Yoshida, Masasuke; Kinosita, Kazuhiko

2011-07-01

266

Diagnosis of Stator-Winding-Turn Faults of Induction Motor by Direct Detection of Negative-Sequence Currents  

NASA Astrophysics Data System (ADS)

In an AC motor, the quick detection of an initially small fault is important for preventing any consequent large fault. Various detection approaches have been proposed in previous papers, for example, by the Park vector (PV), AI techniques, wavelet analysis, and negative-sequence analysis. This paper proposes a method for diagnosing the stator-winding faults of an induction motor by the direct detection of its negative-sequence current. Before starting the diagnosis, the asymmetry admittances for the considered fault cases are obtained by analysis or simulation. The amplitude and phase of the positive-sequence voltage, Vp, and of the positive-sequence current, Ip, are extracted from the voltage PV and current PV, respectively. The amplitude and phase of the negative-sequence, In, are extracted from the residue. The asymmetry admittance, Ya, is calculated from In and Vp. When the positive-sequence admittance is known, Ya can also be calculated from Yp, Ip, and In. These steps are repeated for each sample time and the motor condition is diagnosed according to the variations in the Ya values. The simulation and experimental results are also shown and the proposed method is investigated and validated.

Kato, Toshiji; Inoue, Kaoru; Yoshida, Keisuke

267

Exploring the possibilities to control the molecular switching properties and dynamics: A field-switchable rotor-stator molecular system.  

PubMed

A bistable, dipolar stator-rotor molecular system-candidate for molecular electronics is investigated. We demonstrate that it is possible to control the intramolecular torsional states and dynamics in this system by applying an appropriate additional electric field (instead of biasing one), achieving fine tuning and modulation of the relevant properties. The electric field effects on the quantities responsible for torsional dynamics (potential energy surface, potential barrier height, quantum and classical transition probabilities, correlation time, HOMO-LUMO gap) are studied from first principles. Our results indicate that it is possible to artificially stabilize the metastable conformational state of the studied molecule. The importance of this is evident, as the current-voltage characteristics of the metastable state are clearly distinguishable from the current-voltage characteristics of the two stable states. We report for the first time exact calculations related to the possibilities to control the thermally induced stochastic switching, and reduce the noise in a practical application. Thus, we believe that the molecule studied in this paper could operate as a field-switchable molecular device under real conditions. PMID:21219021

Petreska, Irina; Pejov, Ljupco; Kocarev, Ljupco

2011-01-01

268

PIV measurements of a jet impinging on an opened rotor-stator system at low gap spacing  

NASA Astrophysics Data System (ADS)

The current work experimentally investigates the flow characteristics of an air jet impinging to an opened rotor-stator configuration at a low nondimensional spacing G=0.02 and very low aspect ratio e/D=0.25. The rotational Reynolds numbers varied from 0.33x10^5 to 5.32x10^5 while the jet Reynolds numbers ranged from 17.2x10^3 to 43x10^3. PIV measurements were performed at three axial planes for the entire disk diameter. The obtained PIV results agreed with those obtained by LDA measurements and numerical simulation reported in Poncet et al. 2005 (Physics of Fluids 17, 075110). A recirculation flow region, which centered at the impinging point and possessed high turbulent intensities, was observed. The mean flow and turbulent intensities were evaluated with the local heat transfer coefficients measured by Pell'e and Harmand 2009 (Applied Thermal Engineering 29: 1532-1543). It is shown that the local peaks and the gradually rising of the radial heat transfer coefficients Nu are due to the secondary peaks and the increases near the outer radius of the turbulent intensity distributions respectively. POD analysis was applied to the cases of the impinging jet with and without rotation. It is shown that the first POD mode captured nearly 60% total kinetic energy and the low-order POD modes revealed a spiral structure in the jet-dominated region.

Nguyen, Thien; Pellé}, Julien; Harmand, Souad

2011-11-01

269

Exploring the possibilities to control the molecular switching properties and dynamics: A field-switchable rotor-stator molecular system  

NASA Astrophysics Data System (ADS)

A bistable, dipolar stator-rotor molecular system-candidate for molecular electronics is investigated. We demonstrate that it is possible to control the intramolecular torsional states and dynamics in this system by applying an appropriate additional electric field (instead of biasing one), achieving fine tuning and modulation of the relevant properties. The electric field effects on the quantities responsible for torsional dynamics (potential energy surface, potential barrier height, quantum and classical transition probabilities, correlation time, HOMO-LUMO gap) are studied from first principles. Our results indicate that it is possible to artificially stabilize the metastable conformational state of the studied molecule. The importance of this is evident, as the current-voltage characteristics of the metastable state are clearly distinguishable from the current-voltage characteristics of the two stable states. We report for the first time exact calculations related to the possibilities to control the thermally induced stochastic switching, and reduce the noise in a practical application. Thus, we believe that the molecule studied in this paper could operate as a field-switchable molecular device under real conditions.

Petreska, Irina; Pejov, Ljup?o; Kocarev, Ljup?o

2011-01-01

270

The Stator Complex of the A1A0-ATP synthase -- Structural Characterization of the E and H Subunits  

PubMed Central

Archaeal ATP synthase (A-ATPase) is the functional homolog to the ATP synthase (F-ATPase) found in bacteria, mitochondria and chloroplasts, but the enzyme is structurally more related to the proton pumping vacuolar ATPase (V-ATPase) found in the endomembrane system of eukaryotes. We have cloned, over-expressed and characterized the stator-forming subunits E and H of the A-ATPase from the thermoacidophilic Archaeon, Thermoplasma acidophilum. Size exclusion chromatography, circular dichroism (CD), MALDI-TOF mass spectrometry and NMR spectroscopic experiments indicate that both polypeptides have a tendency to form dimers and higher oligomers in solution. However, when expressed together or reconstituted, the two individual polypeptides interact with high affinity to form a stable heterodimer. Analyses by gel filtration chromatography and analytical ultracentrifugation show the heterodimer to have an elongated shape, and the preparation to be monodisperse. Thermal denaturation analyses by circular dichroism and differential scanning calorimetry revealed the more co-operative unfolding transitions of the heterodimer in comparison to those of the individual polypeptides. The data are consistent with the EH heterodimer forming the peripheral stalk(s) in the A-ATPase in a fashion analogous to the related V-ATPase.

Kish-Trier, Erik; Briere, Lee-Ann K.; Dunn, Stanley D.; Wilkens, Stephan

2008-01-01

271

Prédiction des vibrations du stator d'une machine à réluctance variable en fonction du courant absorbé  

NASA Astrophysics Data System (ADS)

In order to predict the radial vibration of the stator core of a Doubly Salient Switched Reluctance Motor (D.S.S.R.M.), different causes of vibrations are considered. In this kind of machine, electromagnetic stress is found to be the most significant cause of vibrations. The local magnetic stress distribution, depending on magnetic field and finally on the phase current, is calculated in the case of an unsatured operation. This magnetic stress acts in two ways: a tangential force (torque) and a radial attractive force. This radial force excites the vibration modes of the stator, this vibration behaviour is measured in the aligned position and is identified as a transfert function. Finally several experiments show the good accuracy of this simple model. This model will be later used to study the effect of phase current and of static converter on vibration and acoustic noise emitted by the D.S.S.R.M. L'étude du bruit et des vibrations dans le matériel électrique fait intervenir plusieurs systèmes physiques couplés. Le modèle complet est complexe et ne permet pas d'études paramétriques simples de la structure de la machine, de son alimentation et cela pour différents points de fonctionnement. Dans cet article est présenté un modèle simple permettant de prédire l'accélération radiale d'un Moteur à Réluctance Variable à Double Saillance (M.R.V.D.S.) en fonction du courant d'alimentation. Ce modèle permettra d'étudier ultérieurement l'influence de l'alimentation sur le comportement vibratoire de la machine. En premier lieu, les différentes sources de vibrations d'une machine tournante sont évoquées, pour finalement ne s'intéresser qu'aux efforts d'origine magnétique qui sont prépondérants dans les M.R.V.D.S. Le calcul de ces efforts en fonction du courant est présenté dans le cas d'une machine fonctionnant en régime linéaire (sans saturation magnétique). Ces efforts sont décomposés en une force tangentielle créant le couple de rotation et une force radiale ne créant aucun couple. Les formulations sont appliquées à une M.R.V.D.S. de type 6/4 d'une puissance de 30 W. Une identification expérimentale du comportement vibratoire de la machine à rotor bloqué et en monophasé permet de connaître la réponse de la structure à ces efforts magnétiques. Cette réponse mécanique est identifiée à une fonction de transfert. Le modèle complet prend en compte l'alimentation de la machine, la relation entre le courant d'ajimentation et les efforts ainsi que la réponse vibratoire de la machine à ces efforts. Enfin des résultats expérimentaux originaux permettent de valider le modèle dans le cadre des hypothèses définies.

Camus, F.; Gabsi, M.; Multon, B.

1997-02-01

272

Commande vectorielle de la machine a reluctance variable à stator lisse. Prise en compte de la saturation et de l'amortissement  

NASA Astrophysics Data System (ADS)

This paper deals with the field-oriented control of a smooth stator, non excited salient rotor synchronous machine. First, a nonlinear modelling of the machine, taking into account both damping and saturation effects, is developed in PARK's rotor-bound frame. Then, a vector control strategy, which maintains a constant saturation level in the machine, is set-up. This strategy, wich consists in keeping the stator direct current at a high constant value, allows to linearize the model of the machine and to control it in the same way as a DC machine. A numerical simulation of a VRM, fed by a PWM-VSI and controlled thanks to this control strategy, is built up and the computed results are given and commented. Cet article est consacré à la commande vectorielle d'une machine à réluctance variable à stator lisse et rotor massif. D'abord, une modélisation non linéaire de la machine a été effectuée dans le repère de Park. Cette dernière permet de prendre en compte l'effet d'amortissement dû au rotor massif, ainsi que celui de la saturation inhérent à ce genre de machine. Ensuite, une stratégie de contrôle vectoriel, qui maintient un niveau de saturation constant dans la machine, a été élaborée. Cette stratégie, qui consiste à maintenir le courant direct statorique à une valeur élevée, permet de linéariser le modèle de la machine et ainsi de pouvoir la contrôler comme une machine à courant continu. Une simulation numérique de la machine à réluctance variable, alimentée par un onduleur de tension à MLI et commandée par la stratégie mise au point, a été effectuée. Les résultats de cette simulation sont donnés et commentés à la fin de l'article.

Tounzi, A.; Meibody-Tabar, F.; Sargos, F. M.

1997-04-01

273

A conserved residue, PomB-F22, in the transmembrane segment of the flagellar stator complex, has a critical role in conducting ions and generating torque.  

PubMed

Bacterial flagellar motors exploit the electrochemical potential gradient of a coupling ion (H(+) or Na(+)) as their energy source, and are composed of stator and rotor proteins. Sodium-driven and proton-driven motors have the stator proteins PomA and PomB or MotA and MotB, respectively, which interact with each other in their transmembrane (TM) regions to form an ion channel. The single TM region of PomB or MotB, which forms the ion-conduction pathway together with TM3 and TM4 of PomA or MotA, respectively, has a highly conserved aspartate residue that is the ion binding site and is essential for rotation. To investigate the ion conductivity and selectivity of the Na(+)-driven PomA/PomB stator complex, we replaced conserved residues predicted to be near the conserved aspartate with H(+)-type residues, PomA-N194Y, PomB-F22Y and/or PomB-S27T. Motility analysis revealed that the ion specificity was not changed by either of the PomB mutations. PomB-F22Y required a higher concentration of Na(+) to exhibit swimming, but this effect was suppressed by additional mutations, PomA-N194Y or PomB-S27T. Moreover, the motility of the PomB-F22Y mutant was resistant to phenamil, a specific inhibitor for the Na(+) channel. When PomB-F22 was changed to other amino acids and the effects on swimming ability were investigated, replacement with a hydrophilic residue decreased the maximum swimming speed and conferred strong resistance to phenamil. From these results, we speculate that the Na(+) flux is reduced by the PomB-F22Y mutation, and that PomB-F22 is important for the effective release of Na(+) from PomB-D24. PMID:21636648

Terauchi, Takashi; Terashima, Hiroyuki; Kojima, Seiji; Homma, Michio

2011-06-02

274

Mode-splitting and quasi-degeneracies in circular plate vibration problems: The example of free vibrations of the stator of a traveling wave ultrasonic motor  

NASA Astrophysics Data System (ADS)

In systems with rotational symmetry, bending modes occur in doubly-degenerate pairs with two independent vibration modes for each repeated natural frequency. In circular plates, the standing waves of two such degenerate bending modes can be superposed with a 1/4 period separation in time to yield a traveling wave response. This is the principle of a traveling wave ultrasonic motor (TWUM), in which a traveling bending wave in a stator drives the rotor through a friction contact. The stator contains teeth to increase the speed at the contact region, and these affect the rotational symmetry of the plate. When systems with rotational symmetry are modified either in their geometry, or by spatially varying their properties or boundary conditions, some mode-pairs split into singlet modes having distinct frequencies. In addition, coupling between some pairs of distinct unperturbed modes also causes quasi-degeneracies in the perturbed modes, which leads their frequency curves to approach and veer away in some regions of the parameter space. This paper discusses the effects of tooth geometry on the behavior of plate modes under free vibration. It investigates mode splitting and quasi-degeneracies and derives analytic expressions to predict these phenomena, using variational methods and a degenerate perturbation scheme for the solution to the plate's discrete eigenvalue problem; these expressions are confirmed by solving the discrete eigenvalue problem of the plate with teeth.

Kumar, Ashwin; Krousgrill, Charles M.

2012-12-01

275

Rotordynamic analysis of annular honeycomb-stator turbulent gas seals using a new friction-factor model based on flat plate tests  

NASA Astrophysics Data System (ADS)

A flat plate tester with various honeycomb geometries has been extended to develop a better understanding of the friction-factor behavior of honeycomb surfaces. The friction-factor-jump phenomenon, which is characterized by the dramatic drop and then rise of the friction-factor with increasing Reynolds number, has been explained by acoustic excitation of a large scale coherent flow structure from pressure fluctuation measurements inside the honeycomb cavities. A new friction-factor model based on the flat-plate-test results has been developed as a function of Mach number, dimensionless pressure, and honeycomb geometry variables. A rotordynamic analysis has been developed for centered, turbulent-annular honeycomb-stator seals incorporating the new empirical friction-factor model for honeycomb-stator surfaces. The validity of the new analysis in predicting the rotordynamic and leakage characteristics has been compared to Moody's friction-factor model analysis and experimental data for a short (L/D = 1/6, 25.4 mm long) seal and a longer (L/D = 1/3, 50.8 mm long) seal. The comparisons show that the new honeycomb friction-factor model greatly improves the predictions of leakage and rotordynamic coefficients compared to Moody's friction-factor model for both the short and longer seal, especially, for direct stiffness and cross-coupled stiffness. The new honeycomb friction-factor model predicts leakage and rotordynamic coefficients better for the short than the longer seals.

Ha, Tae Woong

1992-01-01

276

Cold-Air Performance of Free Power Turbine Designed for 112-Kilowatt Automotive Gas-Turbine Engine. II. Effects of Variable Stator-Vane-Chord Setting Angle on Turbine Performance.  

National Technical Information Service (NTIS)

The cold-air performance of the baseline power turbine designed for a 112-kW automotive gas-turbine engine was experimentally determined. Since this acial-flow power turbine has a variable stator for engine control and braking, performance data were taken...

K. L. McLallin M. G. Kofskey

1979-01-01

277

Cold-Air Performance of Free Power Turbine Designed for 112-Kilowatt Automotive Gas-Turbine Engine. 2: Effects of Variable Stator-Vane-Chord Setting Angle on Turbine Performance.  

National Technical Information Service (NTIS)

The cold-air performance of an axial-flow power turbine with a variable stator designed for a 112-kW automotive gas-turbine engine was determined at speeds from 30 to 110 percent of design and at pressure ratios from 1.11 to 2.67. Performance is presented...

K. L. Mclallin M. G. Kofskey

1979-01-01

278

Políticas del sitio web  

Cancer.gov

En el sitio web del NCI se proporcionan enlaces a otros sitios web con fines informativos y para conveniencia del público. Si el usuario selecciona un sitio web externo, saldrá del sitio web del NCI y estará sujeto a las políticas de privacidad y seguridad de dicho sitio.

279

Détermination de régimes transitoires des moteurs à induction par une nouvelle méthode de couplage des champs magnétiques du stator et du rotor  

NASA Astrophysics Data System (ADS)

A model allowing the effective computation of the transient behaviour of deep squirrel cage induction motors is detailed. The principle of the model is that the coupling between the rotor and the stator is made only by the fundamental space harmonic, the other harmonics are forced to vanish through the air gap. The main interest is that in the time step method only the fundamental space harmonic has to be transferred, which allows larger steps than in a punctual transfer. This method can be used when non linearities exist but it is detailed in the paper in the linear case. Nous présentons la modélisation d'un moteur à induction à cage profonde dont la vitesse est donnée et que l'on alimente, à partir d'un instant donné, par des courants qui sont des fonctions connues du temps. Les champs statoriques et rotoriques sont couplés par leur premier harmonique d'espace. L'intérêt de cette méthode est que seul le premier harmonique d'espace est transporté dans le suivi simultané du mouvement et de l'évolution des courants, ce qui autorise des rotations élémentaires plus importantes et donc un temps de calcul nettement réduit. La méthode, généralisable au cas non linéaire, est développée ici dans le cas linéaire.

Bock, J. P.; Laporte, B.; Vinsard, G.

1995-10-01

280

Crystal structure of the cell wall anchor domain of MotB, a stator component of the bacterial flagellar motor: implications for peptidoglycan recognition.  

PubMed

The stator ring of the bacterial flagellar motor is composed of the MotA and MotB proteins that act together to generate a turning force (torque) acting on the FliG ring of the rotor. The C-terminal domain of MotB (MotB-C) is believed to anchor the MotA/MotB complex to peptidoglycan (PG) of the cell wall. The first crystal structures of MotB-C and its complex with N-acetylmuramic acid (NAM) have been determined to 1.6- and 2.3-A resolution, respectively. MotB-C is a dimer, both in solution and in the crystal. The two glycan chains of the PG ligand can be modeled as semirigid helices and docked into the grooves harboring the NAM molecules on the opposite faces of the dimer. The model suggests that a concave hydrophilic surface created upon edge-to-edge beta-sheet dimerization and centered around the 2-fold axis of the dimer can accommodate the peptide cross-bridge linking the two sugar chains. Significant structural similarities were found between MotB-C and the PG-binding domains of reduction-modifiable protein M and peptidoglycan-associated lipoprotein exclude, suggesting that PG recognition by different outer membrane protein A-like proteins may be governed by very similar molecular mechanisms that evidently involve protein dimerization. PMID:18647830

Roujeinikova, Anna

2008-07-22

281

Cross-linking of the endogenous inhibitor protein (IF1) with rotor (gamma, epsilon) and stator (alpha) subunits of the mitochondrial ATP synthase.  

PubMed

The location of the endogenous inhibitor protein (IF1) in the rotor/stator architecture of the bovine mitochondrial ATP synthase was studied by reversible cross-linking with dithiobis(succinimidylpropionate) in soluble F1I and intact F1F0I complexes of submitochondrial particles. Reducing two-dimensional electrophoresis, Western blotting, and fluorescent cysteine labeling showed formation of alpha-IF1, IF1-IF1, gamma-IF1, and epsilon-IF1 cross-linkages in soluble F1I and in native F1F0I complexes. Cross-linking blocked the release of IF1 from its inhibitory site and therefore the activation of F1I and F1F0I complexes in a dithiothreitol-sensitive process. These results show that the endogenous IF1 is at a distance < or = 12 angstroms to gamma and epsilon subunits of the central rotor of the native mitochondrial ATP synthase. This finding strongly suggests that, without excluding the classical assumption that IF1 inhibits conformational changes of the catalytic beta subunits, the inhibitory mechanism of IF1 may involve the interference with rotation of the central stalk. PMID:12678435

Minauro-Sanmiguel, Fernando; Bravo, Concepción; García, José J

2002-12-01

282

Design and Characteristics of Mode-Coupling LiNbO3 Ultrasonic Motor Depended on Width-to-Length Ratio of the Stator Vibrator  

NASA Astrophysics Data System (ADS)

A miniature ultrasonic motor fabricated from a LiNbO3 rectangular plate was studied to improve its rotation characteristics. In this motor, the coupling modes of in-plane longitudinal and flexural modes caused by crystal anisotropy are used to realize a single-phase drive motor. The mode coupling vibrator is designed to have crystal cut angles and the width-to-length ratio W/L of the vibrator shape. In this study, we noted the new coupling condition of W/L? 0.84 compared with the conventional ratio of W/L=0.255. We considered the mechanism of the mode coupling and the design of the stator vibrator by finite element method analysis and experiments. From the results, we fabricated and investigated prototype motors of the vibrator with dimensions of 10× 2.55× 0.5 and 4.10× 3.48× 0.5 mm3. The newly designed motor with the vibrator of W/L=0.849 improved the motor characteristics for the equalization of rotation in both directions.

Hideki Tamura,; Takanori Morooka,; Yasuhiro Yamayoshi,; Manabu Aoyagi,; Takehiro Takano,; Seiji Hirose,

2010-07-01

283

La virtualización del cuerpo a través del \\  

Microsoft Academic Search

Hablar de un cuerpo virtualizado es hablar de su problematización y consecuente actualización, una de las principales consecuencias de este proceso de transfiguración del cuerpo estaría marcada por una adjudicación actualizada de un cambio. El cuerpo es simultáneamente un cuerpo-materia prima, modelo físico para la conversión óptico-iconográfica digital, y un cuerpo interfaz, que permite el acceso a la morfogénesis del

Eduardo Castro Pinzón; José Luis Troncoso

2005-01-01

284

Dinámica del Desempeño Académico  

Microsoft Academic Search

Este trabajo se ocupa del progreso, luego del ingreso, de los estudiantes de la cohorte 2000 de la Facultad de Ciencias Económicas de la Universidad Nacional de La Plata. Si bien hay antecedentes de medición del rendimiento de los estudiantes de la Facultad y sus factores explicativos, se trata de estudios realizados en base a encuestas a alumnos regulares en

Luciano Di Gresia; Alberto Porto

2004-01-01

285

Boletín del Instituto Nacional del Cáncer - 07-20-2010  

Cancer.gov

El doctor Harold Varmus, acompañado de su esposa Constance Casey (centro), presta juramento como director del NCI ante la Secretaria del Departamento de Salud y Servicios Humanos, Kathleen Sebelius, el lunes 12 de julio. (Foto cortesía de Chris Smith) El 12 de julio, el doctor Harold Varmus prestó juramento ante la Secretaria del Departamento de Salud y Servicios Humanos de los Estados Unidos, Kathleen Sebelios, como el decimocuarto director del Instituto Nacional del Cáncer.

286

Multi-cycle recovery of lactoferrin and lactoperoxidase from crude whey using fimbriated high-capacity magnetic cation exchangers and a novel "rotor-stator" high-gradient magnetic separator.  

PubMed

Cerium (IV) initiated "graft-from" polymerization reactions were employed to convert M-PVA magnetic particles into polyacrylic acid-fimbriated magnetic cation exchange supports displaying ultra-high binding capacity for basic target proteins. The modifications, which were performed at 25?mg and 2.5?g scales, delivered maximum binding capacities (Qmax ) for hen egg white lysozyme in excess of 320?mg?g(-1) , combined with sub-micromolar dissociation constants (0.45-0.69?µm) and "tightness of binding" values greater than 49?L?g(-1) . Two batches of polyacrylic acid-fimbriated magnetic cation exchangers were combined to form a 5?g pooled batch exhibiting Qmax values for lysozyme, lactoferrin, and lactoperoxidase of 404, 585, and 685?mg?g(-1) , respectively. These magnetic cation exchangers were subsequently employed together with a newly designed "rotor-stator" type HGMF rig, in five sequential cycles of recovery of lactoferrin and lactoperoxidase from 2?L batches of a crude sweet bovine whey feedstock. Lactoferrin purification performance was observed to remain relatively constant from one HGMF cycle to the next over the five operating cycles, with yields between 40% and 49% combined with purification and concentration factors of 37- to 46-fold and 1.3- to 1.6-fold, respectively. The far superior multi-cycle HGMF performance seen here compared to that observed in our earlier studies can be directly attributed to the combined use of improved high capacity adsorbents and superior particle resuspension afforded by the new "rotor-stator" HGMS design. PMID:23335282

Brown, Geoffrey N; Müller, Christine; Theodosiou, Eirini; Franzreb, Matthias; Thomas, Owen R T

2013-02-22

287

El pronóstico del cáncer  

Cancer.gov

Hoja informativa sobre la predicción de resultados y recuperación de una enfermedad, y sobre cómo las estadísticas ayudan a los médicos a hacer una estimación del pronóstico de un paciente con cáncer.

288

Il problema del litio.  

NASA Astrophysics Data System (ADS)

Contents: 1. Introduzione. 2. La nucleosintesi del Big Bang. 3. Il litio nelle stelle di popolazione II. 4. I modelli stellari standard. 5. Il litio negli ammassi aperti. 6. Meccanismi di distruzione "non standard". 7. I modelli non-standard applicati alla popolazione II. 8. L'evoluzione Galattica del litio. 9. Quali stelle producono litio? 10. Il litio come elemento chiave per dare un nome agli oggetti stellari più minuscoli. 11. Conclusioni.

D'Antona, F.

1995-03-01

289

Fisiopatología del estreñimiento  

Microsoft Academic Search

ResumenEl estreñimiento es un trastorno extremadamente frecuente en la infancia, responsable de hasta el 25% de todas las consultas gastroenterológicas pediátricas y el 3% de todas las consultas pediátricas ambulatorias. En el 90% de los casos el origen del trastorno es funcional y sólo en un 10% existe un problema orgánico subyacente. Entre las causas orgánicas corrientes del estreñimiento infantil

Peter J. Milla

2007-01-01

290

Control del cáncer y salud mundial: noticia del Instituto Nacional del Cáncer (NCI)  

Cancer.gov

En combinación con una reunión de alto nivel de las Naciones Unidas sobre enfermedades no transmisibles en países en vías de desarrollo, el doctor Harold Varmus, director del NCI, y el doctor Ted L. Trimble, del NCI, han publicado un comentario en Science Translational Medicine sobre “La integración del control del cáncer en la salud mundial" (Integrating Cancer Control into Global Health).

291

Boletín del Instituto Nacional del Cáncer - 02-02-2010  

Cancer.gov

En un estudio clínico en fase inicial que probó una vacuna terapéutica en pacientes con leucemia mieloide crónica (LMC) que tomaban el fármaco imatinib (Gleevec), no se pudieron detectar células cancerosas en 7 de los 19 participantes por un tiempo promedio de 22 meses. Los resultados del estudio fueron publicados en el número del 1º de enero de la revista Clinical Cancer Research.

292

Cáncer de cuello del útero o uterino  

Cancer.gov

Información acerca del cáncer de cérvix (cervical o cuello uterino), lo cual incluye temas como tratamiento, prevención, causas, factores de riesgo, exámenes selectivos de detección, estudios clínicos y estadísticas del Instituto Nacional del Cáncer.

293

EL ORIGEN BIOLÓGICO DEL DERECHO  

Microsoft Academic Search

En este trabajo se aborda el posible origen evolutivo del derecho como una consecuencia del desarrollo social de nuestra especie. Otras especies con sistemas sociales similares presentan varias reglas para la convivencia en grupo. Algunas de estas reglas son comunes en todas las especies con comportamiento social. El desarrollo de la sociobiología en las últimas décadas es una herramienta importante

Axel P. Retana-Salazar

294

Alberto del Pozo  

NSDL National Science Digital Library

The Cuban Heritage Collection of the University of Miami Libraries was a recipient of 17 original illustrations by Alberto del Pozo in 1998 from the Campilli family. "The Oricha Collection" is their gift, and it contains illustrations in pen, crayon, and ink and the collection "pays homage to the primary gods and goddesses that comprise the Afro-Cuban religion of Santer'a." The "Introduction" near the top of the page, is a good place for visitors to start learning about Pozo, who was a Parson's School of Design-trained, Cuban artist who died at the age of 47. The "Biographical Sketch" is worth looking at as well. Examples of his colorful, heavily patterned and symbolism-intensive drawings of Santeria gods and goddesses can be found in the link "Gallery". The description of each drawing is given in English and Spanish. Finally, visitors interested in more information on the Santeria, can look at the "Further Readings" link for authoritative books on the subject.

295

Sulla struttura eletronica del nitrobenzolo  

Microsoft Academic Search

Riassunto  È presentato un calcolo di alcune grandezze fisiche del nitrobenzolo mediante il metodo M.O. con una ragionevole scelta dei\\u000a parametri necessari. Per il momento elettrico, la frequenza del primo massimo di assorbimento nell’ultravioletto, le densità\\u000a elettroniche, gli ordini di legame, gli indici di valenza libera e l’energia di risonanza si ottengono valori in ottimo accordo\\u000a con le previsioni. Anche il

M. Simonetta; A. Vaciago

1954-01-01

296

Annular stator structure for a rotary machine  

SciTech Connect

In an axial flow turbofan gas turbine engine of the type having an axis Ar and being dividable into four quadrants about the axis Ar, an engine casing extending circumferentially about the axis Ar, a fan casing spaced radially outwardly from the engine casing leaving an annular flow path for working medium gases extending circumferentially therebetween, and struts extending from the engine casing to the fan casing across the working medium flow path, each strut being attached to the fan casing at one end and to the engine casing at the other end, the improvement is described which comprises: an array of guide vanes extending radially across the working medium flow path and disposed about the axis Ar such that each quadrant has at least one of the guide vanes disposed in the quadrant, each of the guide vanes being attached to the engine casing and being attached to the fan casing, each of the guide vanes having a free length and having an installed length at installation and under non-operative conditions which is greater than the free length such that under normal operative conditions the guide vanes are placed in tension, the engine casing is placed in tension, and the fan casing is placed in compression.

Chaplin, G.F.; Lucas, A.W. Jr.

1988-02-02

297

Ceramic turbine stator vane and shroud support  

DOEpatents

A support system for supporting the stationary ceramic vanes and ceramic outer shrouds which define the motive fluid gas path in a gas turbine engine is shown. Each individual segment of the ceramic component whether a vane or shroud segment has an integral radially outwardly projecting stem portion. The stem is enclosed in a split collet member of a high-temperature alloy material having a cavity configured to interlock with the stem portion. The generally cylindrical external surface of the collet engages a mating internal cylindrical surface of an aperture through a supporting arcuate ring segment with mating camming surfaces on the two facing cylindrical surfaces such that radially outward movement of the collet relative to the ring causes the internal cavity of the collet to be reduced in diameter to tightly engage the ceramic stem disposed therein. A portion of the collet extends outwardly through the ring segment opposite the ceramic piece and is threaded for receiving a nut and a compression washer for retaining the collet in the ring segment under a continuous biasing force urging the collet radially outwardly.

Glenn, Robert G. (Lower Moreland Township, Montgomery County, PA)

1981-01-01

298

Unsteady Flows in Rotor-Stator Cascades.  

National Technical Information Service (NTIS)

A time-accurate potential-flow calculation method has been developed for unsteady incompressible flows through two-dimensional multi-blade-row linear cascades. The method represents the boundary surfaces by distributing piecewise linear-vortex and constan...

C. L. Merkle J. Z. Feng T. W. Bein Y. T. Lee

1991-01-01

299

FENOLOGÍA DEL CULTIVO DEL CHILE (CAPSICUM ANNUUM L.)  

Microsoft Academic Search

RESUMEN Datos diarios de temperaturas máximas y mínimas del aire fueron usados para determinar las unidades calor, que sirvieron como referencia para definir las principales etapas fenológicas en seis tipos diferentes de chile (Capsicum annuum). Las unidades calor sirvieron para inferir el período de mayor requerimiento de nutrimentos, así como la relación con la sintomatología de las enfermedades más importantes

Salvador Montes Hernández; Elena Heredia García; J. Alfonso; Aguirre Gómez

300

Space as a Metafictional Marker: Borges' 'Tema del traidor y del héroe' and Bertolucci's Strategia del ragno  

Microsoft Academic Search

:In this study, I analyse space as a key marker of the metafictional characteristic of Jorge Luis Borges' story 'Tema del traidor y del héroe' (in Ficciones) and Bernardo Bertolucci's film Strategia del ragno. I contend that the presentation of space – this understudied 'other' with regard to time in criticism of Borges – is a major aspect of the

Ilka Kressner

301

Space as a Metafictional Marker: Borges' 'Tema del traidor y del héroe' and Bertolucci's Strategia del ragno  

Microsoft Academic Search

In this study, I analyse space as a key marker of the metafictional characteristic of Jorge Luis Borges' story 'Tema del traidor y del héroe' (in Ficciones) and Bernardo Bertolucci's film Strategia del ragno. I contend that the presentation of space – this understudied 'other' with regard to time in criticism of Borges – is a major aspect of the

Ilka Kressner

302

Considerazioni sulla proprieta' insulino-legante del siero del soggetto normale e del diabetico mai trattato con insulina  

Microsoft Academic Search

Riassunto Gli AA. rilevano che i sieri dell'individuo normale e del diabetico mai trattato con insulina sono provvisti di proprietà insulino-legante di entità analoga. In alcuni sieri, sia del soggetto normale che del diabetico, è presente un'attività insulino-legante superiore ai valori massimi normali, che diminuisce dopo aggiunta di µU 500 di insulina bovina.

Michele Lunetta; Giuseppe Calcagno; Luciano Motta; Turiddu Lombardo

1968-01-01

303

Marina Del Rey Subregional Plan.  

National Technical Information Service (NTIS)

The Marina del Ray Subregional Plan was created for submission to the South Coast Regional Commission of the California Coastal Zone Conservation Commission. Since there are not, as yet, any other coastal subregional plans to use as examples, this plan fo...

M. McCoy C. Walecka

1975-01-01

304

Del Mar College GIS Program  

NSDL National Science Digital Library

Del Mar College offers a comprehensive geospatial program with certificates and Associates degrees in GIS. This site includes description of the program and courses, along with further contact information. By clicking on the link for "Geographic Information Systems" you may download a PDF with information about the program.

2010-10-28

305

Del Pezzo surfaces with Du Val singularities  

NASA Astrophysics Data System (ADS)

In this paper we study the problem of existence of orbifold Kaehler-Einstein metrics on del Pezzo surfaces of degree 1 with Du Val singular points. Moreover we compute global log canonical thresholds of del Pezzo surfaces of degree 1 with Du Val singularities and of del Pezzo surfaces of Picard rank 1 with Du Val singularities.

Kosta, Dimitra

2009-04-01

306

Política de comentarios del NCI  

Cancer.gov

Animamos a los usuarios a compartir sus ideas relacionadas con los temas en discusión en las secciones o foros determinados para tal fin en este sitio web u otros sitios administrados por el Instituto Nacional del Cáncer. Revisamos y publicamos los comentarios de acuerdo a la política indicada a continuación. Nos reservamos el derecho, a nuestra completa discreción, a no publicar o eliminar comentarios que no están de acuerdo con nuestra política.

307

DelPhi: a comprehensive suite for DelPhi software and associated resources  

PubMed Central

Background Accurate modeling of electrostatic potential and corresponding energies becomes increasingly important for understanding properties of biological macromolecules and their complexes. However, this is not an easy task due to the irregular shape of biological entities and the presence of water and mobile ions. Results Here we report a comprehensive suite for the well-known Poisson-Boltzmann solver, DelPhi, enriched with additional features to facilitate DelPhi usage. The suite allows for easy download of both DelPhi executable files and source code along with a makefile for local installations. The users can obtain the DelPhi manual and parameter files required for the corresponding investigation. Non-experienced researchers can download examples containing all necessary data to carry out DelPhi runs on a set of selected examples illustrating various DelPhi features and demonstrating DelPhi’s accuracy against analytical solutions. Conclusions DelPhi suite offers not only the DelPhi executable and sources files, examples and parameter files, but also provides links to third party developed resources either utilizing DelPhi or providing plugins for DelPhi. In addition, the users and developers are offered a forum to share ideas, resolve issues, report bugs and seek help with respect to the DelPhi package. The resource is available free of charge for academic users from URL: http://compbio.clemson.edu/DelPhi.php.

2012-01-01

308

Ayuda para usar el sitio web en español del Instituto Nacional del Cáncer  

Cancer.gov

Página de guía que le permite al lector entender la forma en que está organizado el sitio web del Instituto Nacional del Cáncer (NCI), las categorías de información disponibles y las políticas que rigen este sitio web.

309

Los dilemas del desarrollo territorial: repercusiones del zapatismo en la Selva Lacandona de Chiapas1  

Microsoft Academic Search

Este artículo discute los dilemas del desarrollo territorial en la Selva Lacandona. En particular analiza las relaciones entre movimientos sociales, nuevas formas de gobernanza ambiental y desarrollo en esta región del estado de Chiapas, en México. Con base en el llamado enfoque territorial del desarrollo rural (Schejtman y Berdegué, 2004), planteamos que en el contexto actual de globalización, para lograr

Luis Reygadas

310

Aristocracia fantástica: los moderados y la poética del gobierno representativo  

Microsoft Academic Search

La mayor parte de los ideólogos del moderantismo tras la implantación del régimen liberal fueron destacados teóricos de la estética que contribuyeron a fijar el canon del romanticismo en España. Este artículo investiga la influencia de las reflexiones estéticas de autores como Alberto Lista, Nicomedes Pastor Díaz y Alcalá Galiano en su teoría del gobierno representativo. El asunto de fondo

Pablo Sánchez León

2006-01-01

311

33 CFR 80.1118 - Marina Del Rey, CA.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Marina Del Rey, CA. 80.1118 Section 80.1118 Navigation...LINES Pacific Coast § 80.1118 Marina Del Rey, CA. (a) A line drawn from Marina Del Rey Breakwater South Light 1 to Marina Del Rey...

2010-07-01

312

33 CFR 80.1118 - Marina Del Rey, CA.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Marina Del Rey, CA. 80.1118 Section 80.1118 Navigation...LINES Pacific Coast § 80.1118 Marina Del Rey, CA. (a) A line drawn from Marina Del Rey Breakwater South Light 1 to Marina Del Rey...

2009-07-01

313

Dust formation in Nova Del 2013  

NASA Astrophysics Data System (ADS)

We present the result of the IR photometry of Nova Del 2013 obtained at the Crimean Station (Nauchny, Ukraine) of the Sternberg Astronomical Institute. JHKLM photometry was carried out with 125-cm telescope using a InSb-photometer on:

Shenavrin, V. I.; Taranova, O. G.; Tatarnikov, A. M.

2013-09-01

314

Radio-Observaciones del OH EN la Coma del Cometa Halley Desde EL Hemisferio Sur  

NASA Astrophysics Data System (ADS)

Se utilizó una antena de 30 metros del Instituto Argentino de Radioastronomía para observaciones diarias Cf ebrero a abril de 1986) de la transición en 1667 MHz ( ? = 18 cm) del OH en la coma del cometa Halley. De las observaciones realizadas se concluye: 1) El número promedio de moléculas de OH en la coma durante 37 días de observación fue de (8.9±3.5)x1034 moléculas, lo que implica una tasa de producción promedio de OH de 1.8x1029 moléculas seg-1 y consecuentemente una pérdida de masa promedio de 17±6 toneladas seg-1 . Este valor está de acuerdo con las mediciones realizadas por las sondas Vega y Giotto. 2) El monitoreo desde el lAR revela la existencia de variaciones bruscas en los flujos de absorción del OH. Estas variaciones son consistentes con los modelos que representan la producción gaseosa a partir de ejecciones y/o desprendimientos discretos de materia congelada del núcleo. 3) Las variaciones en la densidad de flujo son consistentes con las estimaciones de los tiem- pos de vida medios del H2O y del OH en presencia del campo de radiación solar. 4) Se encuentra una correlación entre la intensidad del flujo absorbido y anisotropías en Ia dinamica de la coma.

Silva, A. M.; Bajaja, E.; Morras, R.; Cersosimo, J. C.; Martin, M. C.; Arnal, E. M.; Poppel, W. G. L.; Colomb, F. R.; Mazzaro, J.; Olalde, J. C.; Boriakoff, V.; Mirabel, I. F.

1987-05-01

315

Precio del agua y relocalización del recurso en la economía andaluza. Una aproximación desde un modelo de equilibrio general aplicado  

Microsoft Academic Search

El objetivo de este trabajo consiste en analizar los efectos que tendría un incremento en la tarifa del agua del sector agrario sobre la conservación del recurso, la eficiencia en el consumo y la posible relocalización del mismo entre los diferentes sectores productivos. La política tarifaria se aplicará sobre el sector agrario debido, por un lado, al excesivo consumo de

M. Alejandro Cardenete; G. J. D. Hewings; E. Velázquez

2005-01-01

316

Comportamento del rame OFHC in acqua di elevata purezza. (Behaviour of OFHC copper in highly pure water).  

National Technical Information Service (NTIS)

In order to gain a wider knowledge of corrosion phenomena in OFHC (oxygen free high conductivity) copper pipes of the stator cooling circuit of a power plant turboalternator, a research program was laid out which is based on the use of an experimental loo...

G. Perboni G. Rocchini G. Brunoro G. Trabanelli

1991-01-01

317

Declaración del Instituto Nacional del Cáncer sobre los exámenes selectivos de detección de cáncer de seno  

Cancer.gov

El Instituto Nacional del Cáncer (NCI) agradece la cuidadosa revisión y análisis que ha hecho la Brigada de Servicios Preventivos de los Estados Unidos de la evidencia con respecto a los exámenes de detección de cáncer de seno para mujeres que tienen un riesgo del promedio.Preguntas y Repuestas

318

Boletín del Instituto Nacional del Cáncer - 3 de enero de 2012  

Cancer.gov

Dra. Rachel Ballard-Barbash Nuevos indicios del papel de la obesidad en el cáncer A medida que ha aumentado la prevalencia de la obesidad alrededor del mundo, se ha incrementado también la preocupación sobre sus consecuencias en la salud pública. Los índices de obesidad se han más que duplicado desde 1980, según la Organización Mundial de la Salud.

319

Preguntas y respuestas acerca del Estudio del Tamoxifeno y Raloxifeno (STAR)  

Cancer.gov

El Estudio del Tamoxifeno y Raloxifeno (STAR, por sus siglas en inglés) es un estudio clínico (un estudio de investigación conducido con voluntarios) diseñado para ver cómo el medicamento raloxifeno (Evista®) se compara con el medicamento tamoxifeno (Nolvadex®) en reducir la incidencia de cáncer del seno en las mujeres con alto riesgo de desarrollar la enfermedad.

320

Intertextual Sexual Politics: Illness and Desire in Enrique Gomez Carrillo's "Del amor", "del dolor y del vicio" and Aurora Caceres's "La rosa muerta"  

ERIC Educational Resources Information Center

|This study explores the intertextuality between Aurora Caceres's "La rosa muerta" (1914) and the novel "Del amor, del dolor y del vicio" (1898) by her ex-husband, Enrique Gomez Carrillo. Caceres strategically mentions Gomez Carrillo's novel in "La rosa muerta" to invite a reading of her work in dialogue with his. Both narratives follow the sexual…

LaGreca, Nancy

2012-01-01

321

Evaluación de elementos estructurales del hábitat del borrego cimarrón en la Sierra del Mechudo, Baja California Sur, México  

Microsoft Academic Search

Habitat lost and fragmentation can result in an isolated and local extinction risk for small populations like Ovis canadensis weemsi Goldman, 1937, in Sierra del Mechudo, Baja California Sur, Mexico. That is why it is important to evaluate the relationship between species and their habitat in order to design management and conservation plans. The object of this study was to

Sergio Alvarez-Cárdenas; Patricia Galina-Tessaro; Sara Díaz-Castro; Israel Guerrero-Cárdenas; Aradit Castellanos-Vera; Erika Mesa-Zavala

322

Near Infrared Photometry of Nova Del 2013  

NASA Astrophysics Data System (ADS)

We continued to follow Nova Del 2013 during the period from 31.15 August 2013 UT through 25.18 September 2013 UT using an As:Si bolometer mounted on the 0.76-m infrared telescope of the University of Minnesota's O'Brien Observatory (Marine on St. Croix, Minnesota, USA). Vega (alpha Lyrae) is used as the standard star.

Cass, A. C.; Carlon, R. L.; Corgan, D. T.; Dykhoff, D. A.; Gehrz, R. D.; Shenoy, D. P.

2013-09-01

323

Andrea del Sarto rehabilitated: a psychoanalytic emendation.  

PubMed

Ernest Jones's "The Influence of Andrea del Sarto's Wife on His Art" (1913) is an early example of psychoanalysis applied to the study of a prominent painter. Greatly influenced by Freud's Leonardo da Vinci and a Memory of His Childhood, Jones gave excessive credence to Vasari's highly prejudicial account of the life of del Sarto, on which the study relied heavily. Jones attempted to account psychologically for the circumstance that del Sarto, though highly skilled and "faultless," was not the equal of the three preeminent masters of the Italian High Renaissance: Leonardo, Michelangelo, and Raphael. Jones's uncritical acceptance of the Vasari biography encouraged him to view Sarto's assumed deficiency as the result of excessive attachment to his wife, a pathological uxoriousness. A contemporary psychoanalytic perspective, with its emphasis on the emotive response of the analyst, requires us to pay attention to the evocative nature of the work of the artist, an approach Jones neglected. In an examination of several paintings, the artist's sensitivity to the position of the spectator is explored, as is the interest in involving the viewer spatially and emotionally. An appreciation for the viewer's position is consistent with a capacity for using projected internal objects for creative purposes. The presence of this capacity suggests a revised view of del Sarto's contribution to art and of his relationship with his wife. PMID:12580329

Trosman, Harry

2002-01-01

324

Quina és la funció del gen clonat?  

Microsoft Academic Search

Presentem una activitat didàctica complementària per a alumnes de segon de batxillerat. A partir d’una seqüència de nucleòtids del genoma de Paenibacillus barcinonensis determinem la regió codificant d’un gen, la proteïna corresponent i la seva funció. Com a annex s’inclou el guió per a l’alumnat.

Margarita Soriano; Francisca Guerola

2008-01-01

325

ECONOMÍAS EXTERNAS Y LOCALIZACIÓN DEL EMPLEO INDUSTRIAL  

Microsoft Academic Search

Es un hecho fácilmente constatable que la actividad económica en gene- ral e industrial en particular se localiza de forma desigual a lo largo de la geografía española. El presente trabajo plantea un modelo que tiene como objetivo analizar la incidencia de las economías externas en la dis- tribución territorial del empleo de los distintos sectores industriales. El modelo incorpora

ELISABET VILADECANS MARSAL

2003-01-01

326

Boletín del Instituto Nacional del Cáncer - 27 de marzo de 2012  

Cancer.gov

Le invitamos a que comparta esta publicación con sus amigos, familiares y colegas y nos ayude a continuar nuestra misión de difundir las investigaciones más recientes sobre la prevención, el tratamiento y la información del cáncer.

327

Els títols dels films de Quentin Tarantino : una perspectiva multilingüe  

Microsoft Academic Search

Els títols de films en llengua anglesa són, avui dia, textos (o paratextos) de gran importància cultural en les societats occidentals. En aquest article ens ocupem de dues qüestions: (1) del fenomen —força popular— de la traducció dels títols de pel·lícules en llengua anglesa que arriben al nostres cinemes; repassem les variades tipologies emprades per analitzar les traduccions dels títols

José Santaemilia; Betlem Soler

2010-01-01

328

Análisis del comportamiento estructural de la basílica del Pilar de Zaragoza  

Microsoft Academic Search

En el artículo se presentan los trabajos de desarrollo y validación de un conjunto de modelos estructurales\\u000ade la basílica del Pilar de Zaragoza planteados con el objetivo de aproximar el estado estructural actual del\\u000atemplo y su nivel de seguridad. Los modelos numéricos se han formulado aplicando el MEF en teoría lineal\\u000ay no lineal, incluyendo el proceso constructivo

Luis E. Romera; Santiago Hernández; José Manuel Reinosa

1970-01-01

329

Boletín del Instituto Nacional del Cáncer - 31 de enero de 2012  

Cancer.gov

Dr. Nils Daulaire Salud mundial a través de la colaboración y el liderazgo Para conmemorar el Día Mundial del Cáncer que tuvo lugar el 4 febrero, el doctor Nils Daulaire, director de la Oficina de Asuntos Internacionales del Departamento de Salud y Servicios Humanos de los Estados Unidos habla sobre las razones por las cuales los Estados Unidos deben participar en iniciativas para mejorar la salud mundial.

330

Estudio para la prevención del cáncer necesita voluntarias: El Estudio del Tamoxifeno y Raloxifeno (STAR) se realiza en Norteamérica  

Cancer.gov

El Estudio del Tamoxifeno y Raloxifeno (STAR, por sus siglas en inglés), uno de los estudios más importantes realizados para la prevención del cáncer del seno, está ahora reclutando voluntarias en más de 400 centros en los Estados Unidos, Puerto Rico y Canadá.

331

Evaporación dinámica del cinturón de asteroides original  

NASA Astrophysics Data System (ADS)

Hemos integrado numéricamente un enjambre de 3000 partículas en la región del cinturón de asteroides, sujetas a las perturbaciones gravitatorias de Júpiter y Saturno. Al cabo de 107 años, se han formado ya todos los gaps de Kirkwood observados en el cinturón actual. El grupo en la resonancia 3/2 es, aunque en menor grado, también visible. Los tiempos de Lyapunov computados para los asteroides sobrevivientes, nos ha permitido encontrar la fracción de ellos que es capaz de sobrevivir por toda la edad del sistema solar, merced a la aplicacion de la relación empírica que vincula dichos tiempos al tiempo en el cual se manifiestan grandes transiciones orbitales. La fracción de supervivientes es de aproximadamente 1/100. El resto de la masa faltante en el cinturón, es atribuible a colisiones catastróficas con cometas en etapas primordiales.

Brunini, A.

332

Motor bearing damage detection using stator current monitoring  

Microsoft Academic Search

This paper addresses the application of motor current spectral analysis for the detection of rolling-element bearing damage in induction machines. Vibration monitoring of mechanical bearing frequencies is currently used to detect the presence of a fault condition. Since these mechanical vibrations are associated with variations in the physical air gap of the machine, the air gap flux density is modulated

Randy R. Schoen; Thomas G. Habetler; Farrukh Kamran; R. G. Bartfield

1995-01-01

333

Using induction motor stator windings to extract speed information  

Microsoft Academic Search

A speed regulator based on a field-oriented control was constructed using speed information available from the moving flux wave in the air gap of an induction motor. The information takes the form of ripples in the flux caused by the motion of rotor bars through the flux wave. This information is accessed by using voltages available from taps taken off

DONALD S. ZINGER; T.A. Lipo; DONALD W. NOVOTNY

1989-01-01

334

Rotor Stator Acoustic Interaction, Death and Birth of Resonance Frequency.  

National Technical Information Service (NTIS)

Guiding and resonance phenomenon near a periodic double cascade of plates has been investigated. Much attention has been paid to the difference from the oscillations near single periodic cascade of plates. It has been demonstrated that the mutual influenc...

E. R. Bartuli

2002-01-01

335

The unsteady aerodynamics of a first stage stator vane row  

NASA Astrophysics Data System (ADS)

The fundamental unsteady aerodynamics on a vane row of an axial flow research compressor stage are experimentally investigated, demonstrating the effects of airfoil camber and steady loading. In particular, the rotor wake generated unsteady surface pressure distributions on the first stage vane row are quantified over a range of operating conditions. These cambered airfoil unsteady data are correlated with predictions from a flat plate cascade inviscid flow model. At the design point, the unsteady pressure difference coefficient data exhibit good correlation with the nonseparated predictions, with the aerodynamic phase lag data exhibiting fair trendwise correlation. The quantitative phase lag differences are associated with the camber of the airfoil. An aft suction surface flow separation region is indicated by the steady state surface static pressure data as the aerodynamic loading is increased. This separation affects the increased incidence angle unsteady pressure data.

Capece, V. R.; Fleeter, S.

1986-03-01

336

Attenuation of magnetic field components through an AC machine stator  

Microsoft Academic Search

Purpose – Non-intrusive magnetic measurements in AC machines are possible with small flat coils stuck on the external surface of the housing of a running motor. The aim of the paper consists in determining transmission coefficients able to give a direct relationship between the weak external flux density and the airgap one. Design\\/methodology\\/approach – An experimental approach shows that the

D. Thailly; R. Romary; D. Roger; J. F. Brudny

2008-01-01

337

Laminar, Transitional, and Turbulent Flows in Rotor-Stator Cavities  

NASA Astrophysics Data System (ADS)

This article reviews the range of flows that may be created within thin cylindrical or annular cavities due to the rotation of one of the confining disks. At low Reynolds numbers, the rotation gives rise to an axisymmetric, radially outward motion near the rotor with a return flow along the stationary disk. As the Reynolds number is raised, this base flow gives way to a shear flow populated by discrete vortices, whether of cylindrical or spiral form, near both the rotating and stationary disks. At Reynolds numbers high enough for turbulent flow to occur, in the twentieth century both experimental and computational studies treated the flow as axisymmetric and steady. Recent research has shown, however, that complex organized structures also persist in the turbulent regime.

Launder, Brian; Poncet, Sébastien; Serre, Eric

2010-01-01

338

Modeling of induction machines including stator and rotor slot effects  

Microsoft Academic Search

Three-phase as well as single-phase induction machines form the backbone of a substantial portion of the adjustable-speed drives' applications. Among the current estimation techniques available for speed-sensorless induction motor drives, speed measurement based on rotor or principal slot harmonics (RSH or PSH) detection in machine line current happens to be a prominent one. In practice, two predominant RSH can be

Subhasis Nandi

2004-01-01

339

Motor bearing damage detection using stator current monitoring  

Microsoft Academic Search

This paper addresses the application of motor current spectral analysis for the detection of rolling-element bearing damage in induction machines. Vibration monitoring of mechanical bearing frequencies is currently used to detect the presence of a fault condition. Since these mechanical vibrations are associated with variations in the physical air gap of the machine, the air gap flux density is modulated

R. R. Schoent; T. G. HabetlerS; F. Kamran; R. G. Bartheld

1994-01-01

340

El valor de uso recreativo del Parque Natural de L'Albufera a través del método indirecto del coste de viaje  

Microsoft Academic Search

La valoración económica de bienes que carecen de mercado, como son los espacios naturales protegidos, proporcionan una valiosa información que puede ser utilizada en el análisis coste-beneficio como fundamento de las decisiones públicas que afectan a la calidad del medio ambiente. En este trabajo se aplica el método indirecto del coste de viaje individual para obtener el valor de uso

S. DEL SAZ SALAZAR; L. PÉREZ Y PÉREZ

1999-01-01

341

A Description of Del Mod and Its Final Evaluation, Final Report, Volume I.  

ERIC Educational Resources Information Center

This monograph presents an overview of five Del Mod System final reports, comments by the project director, financial structure of the Del Mod System, and descriptions of Del Mod Projects. The Del Mod System was concerned with changing the science and mathematics education programs in the state of Delaware. Between 1970 and 1976, Del Mod conducted…

Purnell, Charlotte H.; Bolig, John R.

342

An evening at "La Clinica del Pueblo".  

PubMed

This article describes a typical evening at the Clinica del Pueblo in the Hispanic neighborhood of Adams-Morgan in Washington, D.c. The Clinical del Pueblo began operating in 1983 in response to the urgen medical needs of Central American refugees arriving in the Washington D.c. area. The refugees bring with them severe trauma, fear, and health problems caused by the civil was and exacerbated by inadequate or non-existant health services. Approximately 80,000 Salvadoran refugees live in the area. They do not receive adequate health care for 3 reasons. 1) Because the US goverment is unwilling to recognize them as true refugees, they live with the constant threat of deportatin back to the violence from which they have fled. 2) Refugees lack the ability to pay for private care. 3) Langauage and culture create frightening barriers to health care for the refugees. For those who do seek care, these barriers can lead to the inadequate or incomplete diagnoses and poor compliance and follow-up. Plenty International and the Central American Refugee Center responded to these problems by organizing a free clinic to provide not only medical care but also a training course for volunteers. The director of the clinic organizes the course, the classes are taught by a variety of people including the clinic's volunteer physicians, nurses, and public health educators as well as graduates of previus training courses and people from the wider community. The services of the clinic reach only a small portion of the population in need. However, the fact that free medical services are now available to some Central American refugees make the Clinica del Pueblo an important program. PMID:12281149

Shefsky, M L

1986-01-01

343

UBVJHKLM photometry of Nova Del 2013  

NASA Astrophysics Data System (ADS)

We present the results of the optical and IR photometry of Nova Del 2013 obtained at the Crimean Station (Nauchny, Ukraine) of the Sternberg Astronomical Institute. UBV photometry was carried out with 60-cm Zeiss telescope using a photoelectric photometer on August 15.94 UT: U=4.54+/-0.02, B=5.07+/-0.01, V=5.05+/-0.01; on August 16.80 UT: U=4.54+/-0.01, B=4.85+/-0.02, V=4.68+/-0.01; on August 16.86 UT: U=4.66+/-0.01, B=4.92+/-0.01, V=4.73+/-0.01.

Burlak, A. M.; Shenavrin, I. V.; Tatarnikov, M. A.; Tatarnikova, A. A.

2013-08-01

344

Near Infrared Photometry of Nova Del 2013  

NASA Astrophysics Data System (ADS)

Subjects: Infra-Red, Nova We report RIJHKLM photometry of Nova Del 2013 taken on August 28.13 UT using an As:Si bolometer mounted on the 0.76-m infrared telescope of the University of Minnesota's O'Brien Observatory (Marine on St. Croix, Minnesota, USA). Vega (alpha Lyrae) was used as the standard star. On this date we find: R = 5.6 +/- 0.1, I = 5.2 +/- 0.1, J = 4.5 +/- 0.1, H = 4.7 +/- 0.1, K = 4.7 +/- 0.1, L = 3.3 +/- 0.2, M = +1.8 +/- 0.3.

Cass, C. A.; Carlon, L. R.; Corgan, T. D.; Dykhoff, A. D.; Gehrz, D. R.; Shenoy, P. D.

2013-08-01

345

The paleontological site in the Sierra del Chaparral (Villaluenga del Rosario, Cádiz-Spain)  

Microsoft Academic Search

This article outlines the results obtained during the first study of the Chaparral site (Villaluenga del Rosario, Cádiz, Spain) situated in the karst area of the Sierra de Grazalema. The varied macro- and micro-vertebrate fauna include carnivore, herbivores and rodents, as well as reptiles and amphibians, suggesting an Early Pleistocene age. The taphonomic study of the fauna discovered on the

Francisco Giles Pacheco; Antonio Santiago; José María Gutiérrez; Juan Manuel López-García; Hugues-Alexandre Blain; Gloria Cuenca-Bescós; Jan van der Made; Isabel Cáceres; Nuria García

346

MÚSICA Y AGRUPACIONES DE CARNAVAL A FINALES DEL SIGLO XX EN ANDALUCÍA OCCIDENTAL. LA REVITALIZACIÓN FESTIVA Y EL RENACIMIENTO DEL CARNAVAL  

Microsoft Academic Search

Con este trabajo pretendemos acercarnos al Carnaval de Andalucía occidental a partir de su recuperación durante la Transición y los gobiernos socialistas en la década de los años ochenta del pasado siglo XX. Este proceso tuvo lugar en un marco de participación ciudadana, modernización económica, estado del bienestar, constitución de las comunidades autónomas, sociedad del espectáculo y del entretenimiento, y

Francisco José García Gallardo

2005-01-01

347

Un mito del hambre en el nordeste de Brasil  

Microsoft Academic Search

El objetivo del presente estudio es permitir la comprensión, mediante un abordaje etnográfico, de los significados del hambre en las vivencias de actores sociales que enfrentan la pobreza extrema en un barrio de Salvador, Bahía, Brasil. Los relatos se han analizado con el objeto de entender la construcción de signos inherentes al sufrimiento de quienes padecen de hambre cotidianamente. En

Maria do Carmo S. Freitas; Paulo G. L. Pena

2003-01-01

348

ETNOGRAFÍA DEL GASTO: EL CASO DE UNA EMPRESA TURÍSTICA  

Microsoft Academic Search

El siguiente trabajo (a diferencia de otros) intenta ser un abordaje innovador sobre el tema que denota la etno-psicología del gasto (erogación). Asimismo, su presentación (en forma de comentarios etnográficos o cuaderno de notas) es combinada con datos estadísticos de gran relevancia y comentarios personales del observador durante el trabajo de campo. En este caso, se ha combinado prácticas propias

Maximiliano Korstanje

2008-01-01

349

Del Pezzo surfaces and affine 7-brane backgrounds  

Microsoft Academic Search

A map between string junctions in the affine 7-brane backgrounds and vector bundles on Del Pezzo surfaces is constructed using mirror symmetry. It is shown that the lattice of string junctions with support on an affine 7-brane configuration is isomorphic to the K-theory group of the corresponding Del Pezzo surface. This isomorphism allows us to construct a map between the

Tamás Hauer; Amer Iqbal

2000-01-01

350

The hydrothermal system of Nevado del Ruiz volcano, Colombia  

Microsoft Academic Search

Hot springs and steam vents on the slopes of Nevado del Ruiz volcano provide evidence regarding the nature of hydrothermal activity within the summit and flanks of the volcano. At elevations below 3000 m, alkali-chloride water is discharged from two groups of boiling springs and several isolated warm springs on the western slope of Nevado del Ruiz. Chemical and isotopic

Neil C. Sturchio; Stanley N. Williams; Nestor P. Garcia; Adela C. Londono

1988-01-01

351

confirmation of no X-rays from Nova Del 2013  

NASA Astrophysics Data System (ADS)

Due to an underestimation of the X-ray background for the particular Swift observation of Nova Del 2013 reported by us in ATel #5314, we agree with the non-detection given on ATel #5318 and determine a 3-sigma upper limit to the Nova Del 2013 count rate of 0.013 counts/sec. We apologize for the confusion.

Castro-Tirado, A. J.; Martin-Carrllo, A.; Hanlon, L.

2013-08-01

352

EL USO DEL ADRIAMICIN:UN PROBLEMA SIN SOLUCIÓN AÚN  

Microsoft Academic Search

aunque ésta se halla limitada por su cardiotoxicidad. Para este trabajo, estudio piloto diseñado aunque ésta se halla limitada por su cardiotoxicidad. Para este trabajo, estudio piloto diseñado aunque ésta se halla limitada por su cardiotoxicidad. Para este trabajo, estudio piloto diseñado para determinar si los indicadores del estrés oxidativo pudieran ser marcadores tempranos para determinar si los indicadores del

Belkis Martínez Sánchez; Rubén Castillo Jiménez

353

33 CFR 110.111 - Marina del Rey Harbor, Calif.  

Code of Federal Regulations, 2010 CFR

...Waters 1 2010-07-01 2010-07-01 false Marina del Rey Harbor, Calif. 110.111 Section 110.111 Navigation...REGULATIONS Special Anchorage Areas § 110.111 Marina del Rey Harbor, Calif. An area in the main channel within the...

2010-07-01

354

33 CFR 110.111 - Marina del Rey Harbor, Calif.  

Code of Federal Regulations, 2010 CFR

...Waters 1 2009-07-01 2009-07-01 false Marina del Rey Harbor, Calif. 110.111 Section 110.111 Navigation...REGULATIONS Special Anchorage Areas § 110.111 Marina del Rey Harbor, Calif. An area in the main channel within the...

2009-07-01

355

Orígen del deterioro del medio ambiente en Taiwan: Desajuste entre el modelo de desarrollo y la dotación de recursos naturales  

Microsoft Academic Search

De igual modo que el análisis de los llamados nuevos países industriales asiáticos (NPIAs) abre interesantes matices en el campo de las teorías del desarrollo, poniendo en duda la capacidad explicativa de los enfoques tanto dependentista como neoclásico, el estudio del medio ambiente en esos países aporta visiones nuevas y enriquecidas en lo referente a sus modelos de desarrollo. En

Antonio Rodríguez Carmona

1994-01-01

356

Valoración Económica y Ambiental Aplicada a Casos del Manejo de la Calidad del Aire y Control de la Contaminación  

Microsoft Academic Search

Este documento fue comisionado por la Red de Medio Ambiente del Diálogo Regional de Política para la III Reunión Hemisférica celebrada los días 9 y 10 de marzo de 2004. Durante las últimas décadas se han establecido derechos y obligaciones ciudadanas; se han definido las funciones del Estado y de los organismos públicos responsables en materia ambiental; se han realizado

Luis A. Cifuentes; Luis Rizzi; Héctor Jorquera; Javier Vergara

2004-01-01

357

Carrier frequency of GJB2 gene mutations c.35delG, c.235delC and c.167delT among the populations of Eurasia.  

PubMed

Hearing impairment is one of the most common disorders of sensorineural function and the incidence of profound prelingual deafness is about 1 per 1000 at birth. GJB2 gene mutations make the largest contribution to hereditary hearing impairment. The spectrum and prevalence of some GJB2 mutations are known to be dependent on the ethnic origin of the population. This study presents data on the carrier frequencies of major GJB2 mutations, c.35delG, c.167delT and c.235delC, among 2308 healthy persons from 18 various populations of Eurasia: Russians, Bashkirs, Tatars, Chuvashes, Udmurts, Komi-Permyaks and Mordvins (Volga-Ural region of Russia); Belarusians and Ukrainians (East Europe); Abkhazians, Avars, Cherkessians and Ingushes (Caucasus); Kazakhs, Uighurs and Uzbeks (Central Asia); and Yakuts and Altaians (Siberia). The data on c.35delG and c.235delC mutation prevalence in the studied ethnic groups can be used to investigate the prospective founder effect in the origin and prevalence of these mutations in Eurasia and consequently in populations around the world. PMID:20739944

Dzhemileva, Lilya U; Barashkov, Nikolay A; Posukh, Olga L; Khusainova, Rita I; Akhmetova, Vita L; Kutuev, Ildus A; Gilyazova, Irina R; Tadinova, Vera N; Fedorova, Sardana A; Khidiyatova, Irina M; Lobov, Simeon L; Khusnutdinova, Elza K

2010-08-26

358

El metabolismo social del País Vasco desde el análisis de flujos materiales  

Microsoft Academic Search

La desvinculación de la mejora del bienestar respecto del uso de los recursos y de la contaminación es esencial para lograr un desarrollo sostenible. Para avanzar en esta dirección es preciso partir del conocimiento del metabolismo de la sociedad. Es decir, debemos analizar en qué medida nuestras sociedades “ingieren” materias primas, que son “metabolizadas” para producir bienes y servicios, y

Iñaki Arto

2009-01-01

359

La teoría del desarrollo desigual de Oscar Braun. Un análisis crítico  

Microsoft Academic Search

En este análisis crítico de la teoría del intercambio desigual de Oscar Braun, intentamos movernos consistentemente a través de un número de etapas analíticas distintas. Estas etapas son: a) una discusión sobre el objeto del conocimiento en Braun, sin las restricciones de su propia problemática (sección 3); b) una confrontación del objeto del conocimiento en Braun con el objeto real

Richard Brown; Philip Wright

1979-01-01

360

88. Paso Del Norte Hotel, 115117 South El Paso St., ...  

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

88. Paso Del Norte Hotel, 115-117 South El Paso St., south facade, west side of street - South El Paso Street Historic District, South El Paso, South Oregon & South Santa Fe Streets, El Paso, El Paso County, TX

361

Current Work in Laser Cleaning of the Porta del Paradiso  

NASA Astrophysics Data System (ADS)

This paper summarises the conservation of the Porta del Paradiso, currently underway. It briefly illustrates the two cleaning methods employed and the reasons leading to continue the cleaning of the perimeter panels with laser ablation, describing the various working phases.

Agnoletti, S.; Brini, A.; Nicolai, L.

362

Proposed Bosque Del Apache Wilderness Area, New Mexico.  

National Technical Information Service (NTIS)

The report describes the proposal which recommends that approximately 32,500 acres within the Bosque del Apache National Wildlife Refuge in Socorro County, New Mexico, be designated as wilderness within the National Wilderness Preservation System. Since d...

1972-01-01

363

Del Bueno Recalls Cheese Because Of Possible Health Risk  

NASA Website

Del Bueno of Grandview, WA is recalling all size packages of Queso Fresco Fresh Cheese, Queso Panela Fresh Cheese, Requeson Mexican Style Ricotta Cheese, and Queso Enchilado Dry Cheese because they have the potential to be contaminated with Listeria ...

364

Extreme Environments in Tierra del Fuego, Argentina  

NASA Astrophysics Data System (ADS)

The upper timberline of the Andes Cordillera on the island of Tierra del Fuego at the tip of South America is an environment subject to extreme conditions. In order to further understand this environment, ecosystem parameters were measured within two transects of the Andes at Glaciar Martial and Cerro Guanaco. The measurements included pH, soil temperature, soil moisture, nitrogen, sodium and potassium concentration, chlorophyll absorbance, and irradiance in the ultraviolet range (200-400 nm). These data comprise a survey that serves as a baseline for an intensive research program. Chlorophyll concentration and soil data were within the range of our observations at several other sites, from Lapataia Bay on the southwestern boundary with Chile, through the eastern end of Lake Fagnano. However, unusual levels of solar irradiance were found in the open sites of both transects while those in the forest exhibited lower UV values, suggesting strong absorption and/or reflection by the forest canopy. High levels of UV radiation damage important biomolecules and may be partially responsible for the presence of life forms such as the krummholz belt in the upper timberline. These UV values may be due to the effects of global ozone depletion and the ozone hole. The low temperatures, strong winds, snow and ice-covered soil and especially the exposure to UV radiation make this area an extreme environment for life.

Schultz, C.; D'Antoni, H.; Burgess, S.; Zamora, J.; Skiles, J.

2007-12-01

365

Antenatal Rh prophylaxis is unnecessary for “Asia type” DEL women  

Microsoft Academic Search

BackgroundGenerally Rh-negative patients need to be transfused with Rh-negative red blood cells. For pregnant women carrying Rh-positive fetus, the antenatal anti-D detection and Rh immunoglobulin prophylaxis are required worldwide. In East Asia, a RhD variant, termed “Asia type” DEL, was found in approximately 30% of apparent Rh-negative individuals. The antigenic and molecular properties of the DEL were previously defined. Few

Chao-Peng Shao; Hua Xu; Qun Xu; Guo-Dong Sun; Jian-Ping Li; Bo-Wei Zhang; Xiao-Hua Liang; Zhong Liu; Ying Zhou; Dan Li; Nai-Bao Zhuang

2010-01-01

366

L’eruzione laterale etnea del novembre 1950 — dicembre 1951  

Microsoft Academic Search

Conclusione  L’eruzione etnea del 1950–51 si manifestata quasi senza segni premonitori, dopo una breve (meno di un anno) stasi del vulcano.\\u000a Essa si stabilita in una zona che stata gi teatro di precedenti eruzioni (1811) ed ha avuto un’attivit prevalentemente\\u000a effusiva di notevole durata. La lava emessa ha la composizione mineralogica identica alle lave emesse in questo secolo; essa\\u000a si differenzia

Gustavo Cumin

1954-01-01

367

Los cambios comportamentales y del uso del espacio asociados a la muerte del macho dominante de una manada de lobos ibéricos (canis lupus signatus) en el Parque Zoológico de Barcelona  

Microsoft Academic Search

La dinámica social es uno de los campos más estudiados de la familia Canidae en condiciones de cautividad. En este estudio se pretende determinar cómo la muerte del macho dominante de una manada de lobos alojados en el Parque Zoológico de Barcelona afecta al patrón de actividad diario y al uso del espacio del resto de coespecíficos. Los individuos objeto

Ana Isabel Soriano Giménez; Susana Serrat Navarro; Conrad Ensenyat; Carles Riba; Carmen Maté García

2006-01-01

368

Difusión de resultados iniciales del Estudio del Tamoxifeno y del Raloxifeno (STAR): el fármaco para el tratamiento de la osteoporosis, raloxifeno, es tan efectivo como el Tamoxifeno en la prevención de cáncer de seno invasor  

Cancer.gov

Los resultados iniciales del Estudio del Tamoxifeno y del Raloxifeno, STAR, demuestran que el fármaco raloxifeno, actualmente utilizado para prevenir y tratar la osteoporosis en mujeres posmenopáusicas, funciona tan bien como el tamoxifeno para reducir el riesgo de cáncer de seno entre las mujeres posmenopáusicas que tienen riesgo elevado de padecer la enfermedad. Preguntas y respuestas

369

Ongoing near-infrared observations of V339 Del (Nova Del 2013)  

NASA Astrophysics Data System (ADS)

We report continuing 1.08 to 2.35 micron near-infrared spectroscopy of Nova Del 2013 in the J,H,K bands with the Mount Abu 1.2 meter telescope (+ PRL Near-Infrared NICMOS3 Imager/Spectrograph). Subsequent to our initial report on August 28.674 UT (ATel #5337), spectra of the nova have been obtained at regular intervals. The latest spectra of September 16.5 and 19.5 UT are dominated by strong emission lines but the earlier reported strengths of many of the lines have changed significantly.

Banerjee, D. P. K.; Ashok, N. M.; Joshi, Vishal; Evans, Nye

2013-09-01

370

A Case of Near-triploidy in Myelodysplastic Syndrome with del(5q) Combined with del(1p) and del(13q)  

PubMed Central

Numerical and structural chromosomal abnormalities are common in hematological malignancies. Near-triploidy (58-80 chromosomes) is a numerical abnormality observed in 3% of adult cases of acute lymphoblastic leukemia. Near-triploidy is rare in myeloid lineage hematologic malignancies and compared to near-triploidy in lymphoid malignancies, near-triploidy in myeloid malignancies is associated with poor outcomes. Few studies on near-triploidy in myelodysplastic syndrome (MDS) have been reported, and the clinicopathologic significance of this condition is still unclear. Here, we report a novel case of MDS with near-triploidy and multiple structural chromosomal abnormalities: del(5q) combined with del(1p) and del(13q). These abnormalities were detected by cytogenetic analysis with array comparative genomic hybridization (CGH). Our results suggest that array CGH can be a useful tool for detecting chromosomal abnormalities in patients with MDS.

Kim, Bo-Ram; Kim, Ji-Eun; Woo, Kwang-Sook; Kim, Kyeong-Hee; Kim, Jeong-Man; Lee, Suee; Shaffer, Lisa G.

2012-01-01

371

V339 Del (Nova Del 2013) is a weak non-super-soft X-ray source  

NASA Astrophysics Data System (ADS)

V339 Del (Nova Del 2013) is currently being monitored approximately daily by Swift-XRT. X-ray analysis has been complicated due to optical loading caused by photons from the very bright optical source. (For a discussion of optical loading in the XRT, see our help page.) At early times, the data were collected mainly in Windowed Timing mode to mitigate this issue, and no X-ray source was detected (ATel #5283, #5305, #5318).

Page, K. L.; Beardmore, A. P.

2013-09-01

372

La reparación del daño como mecanismo de tutela de la persona. Del daño a la salud a los nuevos daños extrapatrimoniales  

Microsoft Academic Search

En la actualidad, el operador del Derecho se enfrenta a dos de los más importantes problemas del nuevo derecho de daños: por un lado, la clasificación del perjuicio y, por el otro, la reparación correspondiente a cada una de sus categorías, que debe estar informada por el principio de reparación integral, y que impone en consecuencia considerar más que las

Milagros Koteich Khatib

373

El valor de uso recreativo de los espacios naturales protegidos. Una aplicación de los métodos de valoración contingente y del coste del viaje  

Microsoft Academic Search

En este articulo se presenta una aplicación de dos de las metodologías desarrolladas para medir los beneficios que se derivan del uso recreativo de los bienes ambientales en ausencia de mercado, el método del coste del viaje (MCV) y el de valoración contingente (MVC). La zona objeto de estudio ha sido el Parque Nacional de “Aigüestortes y Estany de Sant

M. FARRÉ PERDIGUER

2003-01-01

374

Componentes naturales y de uso del suelo vulnerables a las variaciones del nivel del mar en la costa atlántica de México  

Microsoft Academic Search

Palabras clave Regionalizaci6n de costas, fislografia, vulnerabilidad costera, uso del suelo Absúact Geomorphological alaradenstia of the mastal iongitudinal prn* and the arrangwent of the physiographical stmcture allowed the rmnition of two zonas: a) the intertidai zone -a basic sntne for dired imoaci of sea leve1 dame: and b) an adjacent peritidál (supralittoral) hnge &n area of cushioning or of polential

Mano Arturo; Ortiz Pérez; Ana Patricia; Méndez Linares

375

Estudio multifrecuencia del medio interestelar cercano a HD 192281  

NASA Astrophysics Data System (ADS)

Una de las causas que modifica la estructura y dinámica del medio interestelar es la acción que los vientos de las estrellas de gran masa ejercen sobre el mismo. En este trabajo, mediante el uso de datos interferométricos obtenidos en la banda de radio en la transición de ?˜21-cm del hidrógeno neutro y de imágenes de la emisión de continuo en las bandas de 408 y 1420 MHz, de imágenes HIRES del satélite IRAS en 60 y 100?m, y de observaciones de continuo obtenidas con radiotelescopios de disco simple en 2695, 4850 y 8350 MHz se ha realizado un estudio multifrecuencia de los efectos que los vientos estelares de HD 192281, una estrella de tipo espectral O5,Vn((f))p, han tenido sobre el medio interestelar que rodea a la misma.

Arnal, E. M.; Cappa, C. E.; Cichowolski, S.; Pineault, S.; St-Louis, N.

376

Estudio multifrecuencia del medio interestelar cercano a HD 192281  

NASA Astrophysics Data System (ADS)

Una de las causas que modifica la estructura y dinámica del medio interestelar es la acción que los vientos de las estrellas de gran masa ejercen sobre el mismo. En este trabajo, mediante el uso de datos interferométricos obtenidos en la banda de radio en la transición de 21-cm del Hidrógeno neutro y de imágenes de la emisión de continuo en las bandas de 408 y 1420 MHz, de imágenes HIRES del satélite IRAS en 60 y 100 micrones, y de observaciones de continuo obtenidas con radiotelescopios de disco simple en 2695, 4850 y 8350 MHz se ha realizado un estudio multifrecuencia de los efectos que los vientos estelares de HD 192281, una estrella de tipo espectral O5 Vn((f))p, han tenido sobre el medio interestelar que rodea a la misma.

Arnal, E. M.; Cappa, C.; Cichowolski, S.; Pineault, S.; St-Louis, N.

377

Categories of massless D-branes and del Pezzo surfaces  

NASA Astrophysics Data System (ADS)

In analogy with the physical concept of a massless D-brane, we define a notion of "" for objects in the derived category. This is defined in terms of monodromy around singularities in the stringy Kähler moduli space and is relatively easy to study using "spherical functors". We consider several examples in which del Pezzo surfaces and other rational surfaces in Calabi-Yau threefolds are contracted. For precisely the del Pezzo surfaces that can be written as hypersurfaces in weighted , the category of objects is a "fractional Calabi-Yau" category of graded matrix factorizations.

Addington, Nicolas; Aspinwall, Paul S.

2013-07-01

378

Fotometría CCD en el campo del cúmulo abierto Ruprecht 58  

NASA Astrophysics Data System (ADS)

La región de Vela-Puppis contiene varios cúmulos cuyo estudio puede brindarnos información acerca de la cinemática y el estado evolutivo de la población estelar en las zonas externas del disco galáctico. A través de observaciones CCD en los filtros UBV en el campo del cúmulo abierto Ruprecht 58 (?2000= 8h 14m 41s, ?2000=-31o 57'), se han determinado por primera vez los parámetros fundamentales de este cúmulo tales como distancia, enrojecimiento y edad. Se analiza también la estructura de su secuencia principal y la presencia de gigantes y binarias.

Giorgi, E. E.; Vázquez, R. A.; Seggewiss, W.; Ostrov, P.; Solivella, G. R.

379

Continuing optical spectroscopy of V339 Del = Nova Del 2013 with the Nordic Optical Telescope and the ARAS Group  

NASA Astrophysics Data System (ADS)

Since our first report (ATel#5312) we have been continuing nightly, almost hourly spectroscopic observations of V339 Del = Nova Del 2013 = PNV J20233073+2046041). Here we report the state at approximately the t_3 point in the photometric decline (see also ATel#5370). Spectra have been obtained with the 2.6 m Nordic Optical Telecope FIbre-fed Echelle Spectrograph (FIES) (R ~ 67000), the Ondrejov Observatory 2m Zeiss coude spectrograph (R = 18000), and a variety of grating and echelle spectrographs of the ARAS group with resolutions ranging from 580 - 11000.

Shore, S. N.; Alton, K.; Antao, D.; Barbotin, E.; Berardi, P.; Bohlsen, P.; Boubault, F.; Boyd, D.; Briol, J.; Buil, C.; Charbonnel, S.; Dubreuil, P.; Dubs, M.; Edlin, J.; de France, T.; Favaro, A.; Garde, O.; Graham, K.; Greenan, D.; Guarro, J.; Hansen, T.; Hyde, D.; Lemoult, T.; Leadbeater, R.; Martineau, G.; Buchet, Y.; Masviel, J. P.; Montier, J.; Pollmann, E.; Ribeiro, J.; Thizy, O.; Terry, J.-N.; Teyssier, F.

2013-09-01

380

First high resolution ultraviolet (HST/STIS) and supporting optical spectroscopy of V339 Del = Nova Del 2013  

NASA Astrophysics Data System (ADS)

V339 Del = Nova Del 2013 was observed with the Space Telescope Imagine Spectrograph (STIS) aboard the Hubble Space Telescope (HST) on 2013 Sept. 18.2 UT from 1140-2888 A using the E140M and G230H gratings at a resolution of ~ 100000. At the time, V ~ 8, shortly after t_3. Continuing spectroscopy was provided by the Astronomical Ring for Access to Spectroscopy (ARAS) at resolutions ranging from 3684 - 7431 A with resolutions ranging from 580 - 11000 with time sequences as short as 10 minutes at resolutions up to 12000.

Shore, S. N.; Schwarz, G. J.; Alton, K.; Antao, D.; Barbotin, E.; Berardi, P.; Blank, T.; Bohlsen, T.; Boubault, F.; Boyd, D.; Briol, J.; Buil, C.; Charbonnel, S.; Dubreuil, P.; Dubs, M.; Edlin, J.; de France, T.; Favaro, A.; Garde, O.; Graham, K.; Greenan, D.; Guarro, J.; Hansen, T.; Hyde, D.; Lemoult, T.; Leadbeater, R.; Martineau, G.; Buchet, Y.; Masviel, J. P.; Montier, J.; Mauclaire, B.; Pollmann, E.; Ribeiro, J.; Schram, B.; Thizy, O.; Terry, J.-N.; Teyssier, F.; Page, K. L.; Osborne, J. P.; Ness, J.-U.; Starrfield, S.; Walter, F. M.; Woodward, C. E.; Bode, M. F.

2013-09-01

381

The novel c.247_249delTTC (p.F83del) GJB2 mutation in a family with prelingual sensorineural deafness.  

PubMed

Non-syndromic hearing loss is one of the most common hereditary determined diseases in human, and the disease is a genetically heterogeneous disorder. Mutations in the GJB2 gene, encoding connexin 26 (Cx26), are a major cause of non-syndromic recessive hearing impairment in many countries and are largely dependent on ethnic groups. Due to the high frequency of the c.35delG GJB2 mutation in the Greek population, we have previously suggested that Greek patients with sensorineural, non-syndromic deafness should be tested for the c.35delG mutation and the coding region of the GJB2 gene should be sequenced in c.35delG heterozygotes. Here we present on the clinical and molecular genetic evaluation of a family suffering from prelingual, sensorineural, non-syndromic deafness. A novel c.247_249delTTC (p.F83del) GJB2 mutation was detected in compound heterozygosity with the c.35delG GJB2 mutation in the proband and was later confirmed in the father, while the mother was homozygous for the c.35delG GJB2 mutation. We conclude that compound heterozygosity of the novel c.247_249delTTC (p.F83del) and the c.35delG mutations in the GJB2 gene was the cause of deafness in the proband and his father. PMID:22484064

Petersen, Michael B; Grigoriadou, Maria; Koutroumpe, Maria; Kokotas, Haris

2012-04-06

382

Screening of 185DelAG, 1014DelGT and 3889DelAG BRCA1 mutations in breast cancer patients from North-East India.  

PubMed

Around 1.35 million people of worldwide suffer from breast cancer each year, whereas in India, 1 in every 17 women develops the disease. Mutations of the Breast Cancer 1 (BRCA1) gene account for the majority of breast/ ovarian cancer families. The purpose of study was to provide a prevalence of BRCA1 germline mutations in the North-East Indian population. In relation to the personal and family history with the breast cancer, we found mutations in 6.25% and 12.5% respectively. Three mutations, 185DelAG, 1014DelGT and 3889DelAG, were observed in our North-East Indian patients in exons 2 and 11, resulting in truncation of the BRCA1 protein by forming stop codons individually at amino acid positions 39, 303 and 1265. Our results point to a necessity for an extensive mutation screening study of high risk breast cancer cases in our North-East Indian population, which will provide better decisive medical and surgical preventive options. PMID:23317271

Hansa, Jagadish; Kannan, Ravi; Ghosh, Sankar Kumar

2012-01-01

383

Contribució al coneixement dels Noctuidae de la Garrotxa (Catalunya) (Lepidoptera: Noctuidae)  

Microsoft Academic Search

L'objecte d'aquest treball és presentar una actualització del catàleg dels Noctuidae de la Garrotxa. Es donen els resultats de l'estudi del material arreplegat per l'autor durant els darrers deu anys i del dipositat en abres col.leccions, i s'inclouen, també totes les dades de la bibliografia existent. El cens de Noctuidae de la Garrotxa queda establert provisionalment en 309 especies. Es

Josep Bellavista i Admetlla

1999-01-01

384

Delia H. Etcheverry participó en 2008 del Seminario \\  

Microsoft Academic Search

El encaje es una técnica textil relativamente nueva; aparece en Europa en el siglo XVI y tiene su apogeo en los siglos XVII y XVIII. Sin embargo, cuando se menciona que un trabajo de encaje está hecho a mano, inmediatamente se lo asocia a una época mucho más anti­ gua, a piezas del pasado que se han quedado en el

Por Delia Etcheverry

385

Racionalidad limitada en la sociedad del riesgo mundial  

Microsoft Academic Search

Durante muchas décadas se ha pretendido que la teoría económica de la elección racional es la teoría general del comportamiento humano de la que carecen las ciencias sociales. Este artículo señala algunas de sus limitaciones. La psicología cognitiva describe los sesgos cognitivos de las personas cuando evalúan la información y eligen entre opciones, los cuales ponen en cuestión la idea

Francisco Augusto Laca Arocena

2012-01-01

386

Il ruolo del turismo per l'integrazione Europea  

Microsoft Academic Search

Nell'Unione Europea l'espansione del settore turi stico è destinato a svolgere un ruolo di grande rilievo, per molteplici motivi. Inn anzitutto il turismo ha un notevole impatto economico, in quanto contribuisce positivamente all a creazione di nuovi posti di lavoro e alla crescita di reddito. Inoltre può potenziare le politiche regionali e la politica agricola comune sostenendo lo sviluppo delle

Giulio Querini; Carmen Bizzarri

2009-01-01

387

Las Máscaras Del Héroe: Radiografía De Un Anti-Héroe  

Microsoft Academic Search

Las máscaras del héroe depicts Spanish society from the Second Republic to the start of the Civil War, a period when Spain was torn by poverty and immorality. This intertextual historical novel portrays figures such as Pedro Luis de Gálvez, the last of the bohemians and a failed writer. We encounter Gálvez through the first-person narration of Navales, who hates

Emilio Ramón

2009-01-01

388

The mercury clock of the Libros del Saber  

Microsoft Academic Search

The Libros del Saber de Astronomia is a compilation of various Arabic astronomical works translated into Castilian in the second half of the thirteenth century, under the direction of King Alfonso X of Spain. A section describing a mercury clock has been suggested to be of particular significance in view of the likely invention of the mechanical clock around this

A. A. Mills

1988-01-01

389

Medicine alternative: il senso del male nella postmodernità  

Microsoft Academic Search

Tra modernità e tradizione. E' palese la fortuna che le medicine cosiddette alternative o complementari stanno riscuotendo negli ultimi anni in Italia, come in molti altri Paesi occidentali. Esse interessano un pubblico sempre più ampio e differenziato, ed occupano ormai una fetta consistente dei servizi sanitari e del relativo mercato. Parallelamente, si diffondono in modo assai ampio certe concezioni culturali

Fabio Dei

390

87. Paso Del Norte Hotel, 115117 South El Paso St., ...  

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

87. Paso Del Norte Hotel, 115-117 South El Paso St., south and east facades, west side of street - South El Paso Street Historic District, South El Paso, South Oregon & South Santa Fe Streets, El Paso, El Paso County, TX

391

¿RAZÕN DE AMOR O DENUESTOS DEL AGUA Y EL VINO?  

Microsoft Academic Search

Las dificultades que plantea para su clasificación genérica, su filiación lingüística y su interpretación estética hacen de la Razón de amor con los Denuestos del agua y el vino un apasionante enigma de la poesía medieval castellana; y el problema central en torno al cual parecen gravitar todas esas dificultades es la aparente dicotomía y falta de unidad de la

Arsenio Pacheco

1974-01-01

392

Assessing Glacier Hazards At Ghiacciaio Del Belvedere, Macugnaga, Italian Alps  

Microsoft Academic Search

The uppermost section of the Valle Anzasca behind and above the community of Macugnaga in the Italian Alps is one of the most spectacular high-mountain land- scapes in Europe, with gigantic rock walls and numerous steep hanging glaciers. Its main glacier, Ghiacciaio del Belvedere at the foot of the huge Monte Rosa east face, is a heavily debris-covered glacier flowing

W. Haeberli; M. Chiarle; G. Mortara; A. Mazza

2002-01-01

393

Interdisciplinary Unit: La Isla del Encanto (The Enchanted Island).  

ERIC Educational Resources Information Center

This document presents a series of 14 lesson plans in an interdisciplinary Spanish unit on "La isla del encanto/The Enchanted Island." The materials were prepared for students in grades 5 or 6 who have had basic Spanish instruction in previous grades. The students should also be familiar with basic concepts in English such as math computation, map…

Ford-Guerrera, Rebecca

394

Medical Ethnobotany of the Teribes of Bocas del Toro, Panama  

Microsoft Academic Search

Ethnomedical uses of 108 medicinal plant species, belonging to 52 families, 89 genera, used by the Teribe Amerindians of Bocas del Toro Province in Panama, along with their socio-cultural practices are reported here. The methods of administration of the herbal remedies, the plant parts used, their families and local names are also documented. The recorded medicinal plants were used mainly

M. P. Gupta; P. N. Solís; A. I. Calderón; F. Guinneau-Sinclair; M. Correa; C. Galdames; C. Guerra; A. Espinosa; G. I. Alvenda; G. Robles; R. Ocampo

2005-01-01

395

Interdisciplinary Unit: La Isla del Encanto (The Enchanted Island).  

ERIC Educational Resources Information Center

|This document presents a series of 14 lesson plans in an interdisciplinary Spanish unit on "La isla del encanto/The Enchanted Island." The materials were prepared for students in grades 5 or 6 who have had basic Spanish instruction in previous grades. The students should also be familiar with basic concepts in English such as math computation,…

Ford-Guerrera, Rebecca

396

Design, aerodynamics and autonomy of the DelFly.  

PubMed

One of the major challenges in robotics is to develop a fly-like robot that can autonomously fly around in unknown environments. In this paper, we discuss the current state of the DelFly project, in which we follow a top-down approach to ever smaller and more autonomous ornithopters. The presented findings concerning the design, aerodynamics and autonomy of the DelFly illustrate some of the properties of the top-down approach, which allows the identification and resolution of issues that also play a role at smaller scales. A parametric variation of the wing stiffener layout produced a 5% more power-efficient wing. An experimental aerodynamic investigation revealed that this could be associated with an improved stiffness of the wing, while further providing evidence of the vortex development during the flap cycle. The presented experiments resulted in an improvement in the generated lift, allowing the inclusion of a yaw rate gyro, pressure sensor and microcontroller onboard the DelFly. The autonomy of the DelFly is expanded by achieving (1) an improved turning logic to obtain better vision-based obstacle avoidance performance in environments with varying texture and (2) successful onboard height control based on the pressure sensor. PMID:22617112

de Croon, G C H E; Groen, M A; De Wagter, C; Remes, B; Ruijsink, R; van Oudheusden, B W

2012-05-22

397

Tratamiento del paludismo pediátrico: Papel de las intervenciones nutricionales  

Microsoft Academic Search

ResumenEl paludismo es una causa primordial de morbilidad y mortalidad en niños, particularmente en África subsahariana. Aunque se ha logrado un progreso considerable en el tratamiento del paludismo pediátrico con el tratamiento de combinación basado en la artemisinina, siguen existiendo numerosos obstáculos que se oponen a la puesta en práctica efectiva de estas nuevas opciones terapéuticas sumamente eficaces. Análogamente, si

Akoto Kwame Osei; Davidson H. Hamer

2008-01-01

398

DISTENSION ABDOMINAL Y EDEMAS POR QUISTE DEL CORDON ESPERMATICO  

Microsoft Academic Search

Resumen La distensión abdominal es un síntoma común, siendo en general la presentación inicial de enfer- medades sistémicas o desórdenes gastrointestinales. Otras causas son infrecuentes. Los quistes del cordón espermático son poco frecuentes, pero aún más su ubicación intraabdominal, su tamaño habitual es insuficiente para producir distensión. El paciente presentado en este caso es un varón con criptorquidia bilateral admitido

GUILLERMO A. KELLER; CECILIA SESSA

399

Historia del Tiempo Presente e Historia de las Relaciones Internacionales  

Microsoft Academic Search

Es la Historia del Presente una disciplina en tiempo de elaboración teórica. El rasgo específico de nuestro presente histórico bien pudiera la sociedad tecnológica en construcción. Puesto que la sociedad tecnológica nos introduce en un entorno desterritorializado con un protagonismo de la información sin precedentes en la historia, intuimos que nos adentramos en una sociedad internacional singular, propia exclusivamente de

Montserrat Huguet Santos

2001-01-01

400

Lo multicultural como mitología y como coartada del racismo  

Microsoft Academic Search

La noción de cultura en tanto que conjunto de caracteres de un colectivo nacional, tribal o religioso, ha venido a reemplazar por equivalencia la noción de raza, desprestigiada por la experiencia nazi. Pero su funcionamiento objetivo es el mismo. Raza, nación y cultura son constructos nacidos a la sombra del Romanticismo, de la reacción antiiluminista. El multiculturalismo es la ideología

Horacio Vázquez Rial

2007-01-01

401

Un Análisis del Testimonio en The Little School: Tales of Disappearance and Survival de Alicia Partnoy  

Microsoft Academic Search

El testimonio, como género en la literatura latinoamericana, es muy único. El punto de vista del autor es distinto ya que se deriva del sufrimiento vivido directamente por el testigo. Lo que hace especial al testimonio es la razón principal por la cual se escribe. El testimonio es un acto político que se basa en la fuerza del espíritu de

Jessica Verbanac

2009-01-01

402

TIPOLOGÍA DE CLASES Y SISTEMA DE EVALUACIÓN EN LA ENSEÑANZA DEL DERECHO EN CUBA  

Microsoft Academic Search

En la enseñanza del Derecho cobra vida un grupo de categorías didácticas, aplicadas al desarrollo sistémico del proceso docente-educativo, que constituyen la base donde se sostiene una parte importante de la teoría pedagógica. Entre estas categorías se encuentran las formas organizativas y la evaluación del aprendizaje, las que poseen un carácter universal, a partir de su expresión en los distintos

Carlos Justo Bruzón Viltres

2010-01-01

403

Síndrome del cuidador de adultos mayores discapacitados y sus implicaciones psicosociales  

Microsoft Academic Search

Objetivo: Describir la prevalencia del síndrome del cuidador y las características psicosociales de los cuidadores de adultos mayores discapacitados. Materiales y métodos: Se realizó un estudio piloto de casos y controles en el Valle del Cauca durante el 2003-2004 para evaluar la funcionalidad familiar (APGAR familiar), la ansiedad y depresión (escala de Goldberg), la presencia de enfermedades (cuidadores y no

ELIANA DUEÑAS; M ARÍA ANGGELINE MARTÍNEZ; B ENJAMÍN MORALES; CLAUDIA MUÑOZ; A NA SOFÍA VIÁFARA; J ULIÁN; A. HERRERA

2006-01-01

404

Fallas estructurales del mercado de maíz. Comentario a Robles y García  

Microsoft Academic Search

El artículo es un esfuerzo valioso por parte de economistas para poner (por fin) a funcionar el instrumental de la teoría económica sobre un tema del que sólo parecen ocuparse antropólogos y agrónomos. La carencia de investigación empírica y de reflexión analítica sobre aspectos centrales de la realidad económica del país habla mal del estado que guarda la disciplina de

Ángel Palerm

1995-01-01

405

Moléculas orgánicas obtenidas en simulaciones experimentales del medio interestelar.  

NASA Astrophysics Data System (ADS)

Las nubes moleculares son regiones de formación de estrellas, con temperaturas cinéticas entre 10-50 K y densidades de 103-106 átomos cm-3. Su materia está formada por gas y polvo interestelar. Estas partículas de polvo están cubiertas por una fina capa de hielo, de unos 0.01 ?m, que contiene H2O y a menudo CO, CO2, CH3OH y NH3. El hielo es presumiblemente irradiado por fotones ultravioleta y rayos cósmicos en las zonas poco profundas de las nubes moleculares y las regiones circunestelares. En un sistema de vacío, P ˜ 10-7 mbar, simulamos la deposición de hielo a partir de 10 K y la irradiación ultravioleta por medio de una lámpara de descarga de hidrógeno activada con microondas. La evolución del hielo se observa por medio de un espectrómetro infrarrojo. De este modo es posible determinar la composición del hielo observado en el medio interestelar y predecir la presencia de moléculas aún no detectadas en el espacio, que han sido producto del procesamiento del hielo en nuestros experimentos. También es posible calentar el sistema hasta temperatura ambiente para sublimar el hielo depositado. Cuando el hielo ha sido previamente irradiado, se observa un residuo compuesto por moléculas orgánicas complejas, algunas prebióticas, como varios ácidos carboxílicos, aminas, amidas, ésteres y en menor proporción moléculas heterocíclicas y aminoácidos. Algunas de estas moléculas podrían detectarse en estado gaseoso por medio de observaciones milimétricas y de radio. También podrían estar presentes en el polvo cometario, cuyo análisis químico está planeado por las misiones Stardust y Rosetta. Mientras tanto, nuestro grupo está llevando a cabo el análisis de partículas de polvo interplanetario (IDPs), algunas de las cuales pueden ser de origen cometario. Al igual que ocurre con los productos obtenidos por irradiación del hielo en nuestros experimentos, algunas IDPs son ricas en material orgánico que contiene oxígeno.

Muñoz-Caro, Guillermo Manuel

406

El tutor del docente en formación, figura necesaria en la formación inicial del profesional de la educación  

Microsoft Academic Search

El desarrollo de la universalización pedagógica ha revitalizado el papel del tutor y actualmente cobra mayor importancia si queremos elevar la calidad en la formación y egreso de los futuros docentes. El tutor debe promover, facilitar, ayudar al docente en formación, creando las condiciones para su crecimiento personal y profesional, sin embargo, se ha detectado que es insuficiente su preparación

Maribel Asín Cala; María Isabel Jiménez Martínez; Imara Lay Bravo

2011-01-01

407

LA CONSOLIDACIÓN DEL HAMBRE Y DEL DERECHO A LA ALIMENTACIÓN EN LAS AGENDAS POLÍTICAS DE AMÉRICA LATINA  

Microsoft Academic Search

América Latina y el Caribe es la única región en desarrollo que puede acabar con el hambre en nuestra generación. Tiene 52,4 millones de personas subnutridas (10% de población) y 9 millones de niños con desnutrición crónica, pero también es la principal productora mundial de alimentos y tiene recursos financieros, naturales, humanos e institucionales para hacer del hambre un recuerdo

Jose Luis Viveros; Niemeyer Almeida Filho

2008-01-01

408

The leukocyte integrin antagonist Del-1 inhibits IL-17-mediated inflammatory bone loss  

PubMed Central

Aging is linked to increased susceptibility to chronic inflammatory diseases several of which, including periodontitis, involve neutrophil-mediated tissue injury. Here, we found that aging-associated periodontitis was accompanied by diminished expression of Del-1 (EDIL3), an endogenous inhibitor of LFA-1 integrin-dependent neutrophil adhesion, and by a reciprocal increase in IL-17 expression. Consistently, IL-17 inhibited gingival endothelial cell expression of Del-1, thereby promoting LFA-1-dependent neutrophil recruitment. Young Del-1-deficient mice developed spontaneous periodontitis featuring excessive neutrophil infiltration and IL-17 expression; disease was prevented in Del-1–LFA-1 and Del-1–IL-17 receptor double-deficient mice. Locally administered Del-1 inhibited IL-17 production, neutrophil accumulation, and bone loss. Therefore, Del-1 suppresses LFA-1-dependent neutrophil recruitment and IL-17-triggered inflammatory pathology and may thus be a promising therapeutic for inflammatory diseases.

Eskan, Mehmet A.; Jotwani, Ravi; Abe, Toshiharu; Chmelar, Jindrich; Lim, Jong-Hyung; Liang, Shuang; Ciero, Paul A.; Krauss, Jennifer L.; Li, Fenge; Rauner, Martina; Hofbauer, Lorenz C.; Choi, Eun Young; Chung, Kyoung-Jin; Hashim, Ahmed; Curtis, Michael A.; Chavakis, Triantafyllos; Hajishengallis, George

2012-01-01

409

FLUJOS DE COMERCIO INTRAINDUSTRIAL DE LAS EXPORTACIONES REPRESENTATIVAS ENTRE VALLE DEL CAUCA, ECUADOR Y VENEZUELA 1980 – 2006  

Microsoft Academic Search

En el presente trabajo se analiza el comportamiento del comercio intraindustrial (CII) de los subsectores representativos de la industria del Valle del Cauca con los países de Ecuador y Venezuela para el período 1980-2006 a través del índice Greenaway y Milner y el índice de Brülhart. De esta forma se corrige el problema de agregación presentado en mediciones anteriores y

Aura María Muñoz Cardona; Lina Johanna Salinas Luna

2009-01-01

410

A model of Nevado del Ruiz Volcano, Colombia  

NASA Astrophysics Data System (ADS)

A workshop was held at the Observatorio Vulcanologico de Colombia in Manizales, Colombia, March 28 to April 1, 1988, to review the accumulated data on the disastrous November 13, 1985, eruption and related activity of Nevado del Ruiz volcano (Figure 1). Approximately 30 scientists from eight countries presented data, developed a preliminary model, and addressed the future problems of Ruiz. The volcano (see Figure 2) erupted just prior to the meeting, covering the meeting site with 1-2 mm of ash.The workshop was convened by Stanley N. Williams (Louisiana State University, Baton Rouge) and Hansjürgen Meyer (Universidad del Valle, Cali, Colombia). A special volume of the Journal of Volcanology and Geothermal Research is planned for the papers and letters presented at the workshop, with some additional contributions. Publication is expected in mid-1989.

Williams, Stanley N.; Meyer, Hansjürgen

411

Recent Optical Spectroscopy of V339 Del 2013  

NASA Astrophysics Data System (ADS)

C. E. Woodward (U. Minnesota), R. M. Wagner (Ohio State U.), R. A. Hounsell (STScI), S. Starrfield (Arizona State U.) report optical spectroscopy of V339 Del obtained on on 2013 October 20.14 UT using the Steward Observatory 2.3 m Bok telescope on Kitt Peak with the B&C spectrograph covering the spectral range 325.0 to 925.0 nm at a spectral resolution of ~0.63 nm. In addition, we obtained an earlier spectrum of V339 Del on 2013 September 5.14 UT with the 2.4 m Hiltner telescope of the MDM Observatory on Kitt Peak using the OSU CCD spectrograph (CCDS) and covering the spectral range 320.0 to 965.0 nm at a spectral resolution of 0.9 nm.

Woodward, C. E.; Wagner, R. M.; Hounsell, R. A.; Starrfield, S.

2013-10-01

412

Biological and behavioral determinants of fertility in Tierra del Fuego.  

PubMed

The reproductive history of 182 women in postreproductive life or near menopause from the Chilean part of Tierra del Fuego was traced back by means of familial interviews. These postmenopausal women represent the population since almost the beginning of the settlement, and their reproductive years were spent on the island. Path analysis was applied to analyze fertility determinants of these women and to propose a complex model of interconnections among factors. The reproductive history of these women is characterized by a long fertile span, a short childbearing period, and low fertility. Age at menarche is relatively late, and the age of the women at first birth is mainly determined by their late age at marriage. The use of contraception is related to both spacing and stopping behaviors. The late age of women at marriage, the rhythm of conception, and practices of contraception are proposed as the main determinants of fertility in Tierra del Fuego. PMID:15386216

Pascual, J; García-Moro, C E; Hernández, M

2005-05-01

413

El ``Aula del Cel'': astronomy approaching high school  

NASA Astrophysics Data System (ADS)

The “Aula del Cel” is a project carried out by the Astronomical Obsevatory of the University of Valencia, Spain. It offers high-school teachers a tool for teaching Astronomy to 10 to 17 year-old students. Different programs, experiments, and audiovisual presentations have been prepared by a team formed both by professional astronomers and teachers, and are offered in a format chosen to suit each particular age and curriculum group. Special sessions have been designed for students with special needs (for example blind or autistic children) in close contact with the pedagogical teams responsible for their education. Nearly three thousand students have already visited the “Aula del Cel” over the first six months that it has been offered to the school community.

Ortiz-Gil, A.; Gómez Collado, M.; Gallego Calvente, A. T.

414

UTILIZZO DEL TRAMADOLO PER VIA EPIDURALE NEL CANE: CASE REPORT  

Microsoft Academic Search

RIASSUNTO In questo lavoro è stato impiegato e descritto l'utilizzo del Tramadolo per via epidurale durante l'anestesia in un cane che affronta, in successione, tre interventi nella stessa seduta operatoria; il primo in regione perineale seguito da orchiectomia e successivamente l'exeresi di una grossa neoformazione sul gomito. La somministrazione epidurale lombo-sacrale effettuata con Tramadolo a 2mg\\/kg diluito 1:1 in soluzione

Pierre MELANIE

415

Descripción del coronógrafo a ser instalado en Argentina (MICA)  

NASA Astrophysics Data System (ADS)

El ``Coronógrafo de espejo para Argentina'' es un telescopio solar terrestre a ser colocado en el Observatorio Astronómico Félix Aguilar (El Leoncito), antes de finalizar 1996, como parte de un programa de ciencia bilateral entre Alemania y Argentina. Eclipses fotográficos de alta resolución han revelado que la corona solar es altamente estructurada y variable. De hecho, está contínuamente deformada y moldeada por los movimientos convectivos de los extremos de los arcos magnéticos en la fotosfera, estando, en muchas oportunidades, afectada por explosivas liberaciones de energía. MICA, en conjunción con otros telescopios solares espaciales y terrestres, tratará de contribuir al entendimiento de cuestiones fundamentales de la física solar. Entre ellas: cómo la corona está siendo calentada, dónde y cómo el viento solar es acelerado, qué causa los transitorios coronales, etc. Para ello investigará la distribución de los parámetros del plasma y su evolución con el tiempo, la estructura espacial de la corona en fina y gran escala, procesos que ocurren en los transitorios coronales y factores que los disparan, etc. Para responder a estas cuestiones MICA observará la atmósfera solar por sobre el limbo entre 1.1 y 2 radios solares aproximadamente, usando un nuevo tipo de sistema coronográfico que permite suprimir el brillo del disco solar suficientemente bien, tomando las imágenes con una cámara CCD de 1024x1024 pixels, codificada en 12 bits, pudiendo el mismo ser operado en forma remota. En la presente exposición describiremos las características del instrumento, cómo será controlado y qué esperamos observar basados en las imágenes obtenidas por los telescopios de similares características LASCO C1 a bordo del SOHO y PICO (ubicado en el Observatorio de Pic du Midi, Francia).

Stenborg, G.; Francile, C.; Schwenn, R.; Epple, A.; Rovira, M.

416

An erupted migmatite from Cerro del Hoyazo, SE Spain  

Microsoft Academic Search

The almandine-bearing biotite-cordierite-labradorite dacite of the Cerro del Hoyazo is part of the Neogene volcanic range in SE Spain, extending roughly from Cabo de Gata to Cartagena. About 1 vol. % of the lava consists of rock inclusions, measuring over 1 cm, made up of almandine-biotite-sillimanite gneiss, quartz-cordierite gneiss and spinel-cordierite rock. On the ground of their abundance, chemical composition,

H. P. Zeck

1970-01-01

417

Steroidal saponins from the aerial parts of Tribulus alatus Del  

Microsoft Academic Search

Six steroidal glycosides (1–6) were isolated from the aerial parts of Tribulus alatus Del. (Zygophyllaceae), together with one known cholestane, one spirostane, and six flavonol glycosides. Among them, 1 and 2 possess a furostane-type aglycone, 3 and 6 a cholestane structure, and 4 and 5 a spirostane skeleton. Their structural elucidation was accomplished by extensive spectroscopic methods including 1D (1H,

Abeer Temraz; Omayma D. El Gindi; Hazem A. Kadry; Nunziatina De Tommasi; Alessandra Braca

2006-01-01

418

Prenatal Care in the Paso del Norte Border Region  

Microsoft Academic Search

OBJECTIVES: The impact of a Medicaid-managed care system on access to prenatal care was investigated.STUDY DESIGN: Postpartum interviews and medical chart abstractions were conducted among 493 Hispanic women who reside on the El Paso Texas\\/Juarez Mexico border (the Paso del Norte region). Descriptive analysis identified barriers and facilitators to prenatal care. Logistic regression identified the impact of social and demographic

Judith T Fullerton; Carlene Nelson; Rachel Shannon; Julia Bader

2004-01-01

419

L'Aula del Cel: Communicating Astronomy at School Level  

NASA Astrophysics Data System (ADS)

L'Aula del Cel (The "Sky Classroom") is an effort to bring astronomy closer to school children. It is a project led by the Astronomical Observatory of the University of Valencia in collaboration with the regional education authorities. It has been running for two years and it has been a big success, with nearly three thousand students visiting the Aula during the school term.

Ortiz-Gil, A.; Gomez-Collado, M.; Gallego-Calvente, A. T.

2005-12-01

420

Correction: First high resolution ultraviolet (HST/STIS) and supporting optical spectroscopy of V339 Del = Nova Del 2013  

NASA Astrophysics Data System (ADS)

Due to an error in transcription, the distance is given incorrectly in the text of ATel#5409. Along with the typo "Space Telescope Imaging Spectrograph", the text should read: Comparing these STIS UV spectra with high resolution IUE spectra of the CO nova OS And 1986 obtained between 12 days (LWP) and 22 days (SWP) after optical discovery (1986 Dec. 17, 27 respectively) shows a very close agreement such that when independently dereddened, the ratio of V339 Del to OS And between 1200 and 1900A is ~1.5 in flux (similar in the 2000-3000A range but more uncertain because of the earlier date of the long wavelength IUE observation), indicating that the distance to V339 Del is about 4.2 kpc (distance to OS And ~ 5.1 kpc with E(B-V)=0.25+/-0.05, see Schwarz et al.

Shore, S. N.

2013-09-01

421

PLANTAS INTRODUCIDAS EN EL PARQUE NACIONAL TORRES DEL PAINE, CHILE ALIEN PLANTS IN TORRES DEL PAINE NATIONAL PARK, CHILE  

Microsoft Academic Search

We report 61 new records of alien plants for Torres del Paine National Park. The park is located in the Magellan Region (49°21'-51°08'S y 73°07'-74°52'O), with an area of 181.414 ha. The study area has 21 families, 65 genera and 85 alien species. The families with the largest number of species are Poaceae (22 spp.), Asteraceae (11 spp.) and Caryophyllaceae

Erwin Domínguez; Arve Elvebakk; Clodomiro Marticorena; Aníbal Pauchard

422

El Vallès Oriental : problemes induïts per l'artificialització del sòl i la preservació del medi ambient  

Microsoft Academic Search

El paisatge i els recursos naturals al Vallès Oriental estan sotmesos a una forta pressió deguda a la progressiva artificialització del medi. L'article proposa una metodologia per tal d'avaluar l'impacte d'aquesta pressió i les mesures correctores que s'hi apliquen. Així, comença per establir una tipologia d'àrees que permet distingir entre municipis desenvolupats, dinàmics, primaris i desafavorits. A continuació proposa un

Jordi Bertran

2008-01-01

423

Einfluss der Wechselwirkung Rotor/Stator auf die Rotor-Filmkuehlung. Abschlussbericht. (Influence of rotor/stator-interaction on film cooling at the rotor leading edge. Final report).  

National Technical Information Service (NTIS)

The knowledge about the transient behavior of the boundary layer is quite necessary to achieve an effective cooling of turbine rotor blades that are highly stressed both mechanically and thermally. In this work, experiments were carried out for a single s...

D. Bohn A. Rungen

1996-01-01

424

Stator Bar Vibration Sensors and Fiber-Optic Accelerometers New Tools Used to Measure Stator Winding Vibration in Large Turbine Generators  

Microsoft Academic Search

Vibration analysis has been conducted on large rotating machines for many decades. Proximity probes and accelerometers are traditionally used to measure bearing and shaft vibration in an effort to keep mechanical condition in check. Simple measurement of amplitude, to the more complex analysis such as Fast Fourier Transforms, are made by maintenance personnel in an effort to identify the source,

Mike Hoffer; Andrew Tesla

425

Su inversioni del campo elettrico terrestre a cielo sereno e una loro possibile spiegazione  

Microsoft Academic Search

\\u000a Sunto  Viene descritto un andamento anomalo del gradiente di Potenziale al Col d’Olen sul Monte Rosa durante una giornata che, dalle\\u000a condizioni atmosferiche, si poteva giudicare del tutto normale.\\u000a \\u000a Del fenomeno si dà una spiegazione plausibile dimostrando corne sia possibile la formazione di cariche spaziali solo che a\\u000a una certa distanza dalla stazione si trovino nubi o semplici strati di nebbia

G. Aliverti; M. C. Montù

1931-01-01

426

VEGF: A modifier of the del22q11 (DiGeorge) syndrome?  

Microsoft Academic Search

Hemizygous deletion of chromosome 22q11 (del22q11) causes thymic, parathyroid, craniofacial and life-threatening cardiovascular birth defects in 1 in 4,000 infants. The del22q11 syndrome is likely caused by haploinsufficiency of TBX1, but its variable expressivity indicates the involvement of additional modifiers. Here, we report that absence of the Vegf164 isoform caused birth defects in mice, reminiscent of those found in del22q11

Ingeborg Stalmans; Diether Lambrechts; Frederik De smet; Sandra Jansen; Jian Wang; Sunit Maity; Paige Kneer; Maren von der Ohe; Ann Swillen; Christa Maes; Marc Gewillig; Daniel G. M. Molin; Peter Hellings; Thurid Boetel; Maartin Haardt; Veerle Compernolle; Mieke Dewerchin; Stephane Plaisance; Robert Vlietinck; Beverly Emanuel; Adriana C. Gittenberger-de Groot; Peter Scambler; Bernice Morrow; Deborah A. Driscol; Lieve Moons; Camila V. Esguerra; Geert Carmeliet; Annett Behn-Krappa; Koen Devriendt; Désiré Collen; Simon J. Conway; Peter Carmeliet

2003-01-01

427

The highly prevalent BRCA2 mutation c.2808_2811del (3036delACAA) is located in a mutational hotspot and has multiple origins.  

PubMed

BRCA2-c.2808_2811del (3036delACAA) is one of the most reported germ line mutations in non-Ashkenazi breast cancer patients. We investigated its genetic origin in 51 Spanish carrier families that were genotyped with 11 13q polymorphic markers. Three independent associated haplotypes were clearly distinguished accounting for 23 [west Castilla y León (WCL)], 20 [east Castilla y León (ECL)] and 6 (South of Spain) families. Mutation age was estimated with the Disequilibrium Mapping using Likelihood Estimation software in a range of 45-68 and 45-71 generations for WCL and ECL haplotypes, respectively. The most prevalent variants, c.2808_2811del and c.2803G > A, were located in a double-hairpin loop structure (c.2794-c.2825) predicted by Quikfold that was proposed as a mutational hotspot. To check this hypothesis, random mutagenesis was performed over a 923 bp fragment of BRCA2, and 86 DNA variants were characterized. Interestingly, three mutations reported in the mutation databases (c.2680G > A, c.2944del and c.2957dup) were replicated and 20 affected the same position with different nucleotide changes. Moreover, five variants were placed in the same hairpin loop of c.2808_2811del, and one affected the same position (c.2808A > G). In conclusion, our results support that at least three different mutational events occurred to generate c.2808_2811del. Other highly prevalent DNA variants, such as BRCA1-c.68_69delAG, BRCA2-c.5946delT and c.8537delAG, are concentrated in hairpin loops, suggesting that these structures may represent mutational hotspots. PMID:23929434

Infante, Mar; Durán, Mercedes; Acedo, Alberto; Sánchez-Tapia, Eva María; Díez-Gómez, Beatriz; Barroso, Alicia; García-González, María; Feliubadaló, Lídia; Lasa, Adriana; de la Hoya, Miguel; Esteban-Cardeñosa, Eva; Díez, Orland; Martínez-Bouzas, Cristina; Godino, Javier; Teulé, Alexandre; Osorio, Ana; Lastra, Enrique; González-Sarmiento, Rogelio; Miner, Cristina; Velasco, Eladio A

2013-08-08

428

CHEK2 1100delC and Del5395bp mutations in BRCA-negative individuals from Serbian hereditary breast and ovarian cancer families.  

PubMed

Purpose: Hereditary breast/ovarian cancer (HBOC) occurs in families with several members affected. Most HBOC is caused by mutations in high penetrance BRCA genes accounting for about 5% of all breast cancers. There is a large number of genes with moderate or low penetrance, contributing to non-BRCA aggregation of breast and ovarian cancers. In the present study, we evaluated the presence and frequency of 1100delC and Del5395 mutations in CHEK2 gene in Serbian BRCA-negative HBOC cases. Methods: We analyzed 57 BRCA-negative subjects from high risk breast/ovarian cancer families from Serbia for CHEK2 1100delC and Del5395 mutations. We used two multiplex allele specific PCR in order to detect them. All suspected positive cases were compared with controls and confirmed by DNA sequencing. Results: 1100delC was not detected in the tested group. However, we detected one Del5395 mutation in a female diagnosed with breast cancer at the age of 32 and with apparent family history of breast cancer (her mother and sister were diagnosed with breast cancer at 42 and 39 years of age, respectively). The frequency of Del5395 mutation in our tested group was 1.7% (1/57). Conclusions: 1100delC variant in CHEK2 gene was not present in the tested subjects from HBOC families in Serbia. However, the finding of Del5395 mutation does not allow us to discard a possible involvement of this gene in breast cancer susceptibility in Serbian population. It would be of great interest to assess the distribution of this large deletion in other countries from the Balkan region in order to assess its geographical distribution and possible founder effect. PMID:24065469

Krivokuca, A; Dobricic, J; Brankovic-Magic, M

429

Distribución del continuo ultravioleta e infrarrojo en estrellas Be  

NASA Astrophysics Data System (ADS)

Estamos interesados en interpretar los excesos de flujo infrarrojo y/o ultravioleta observados en estrellas Be con respecto al de estrellas B normales, así como su posible correlación. Una envoltura rodeando la estrella distingue una estrella Be de una B normal; para explicar las observaciones es necesario entonces tener en cuenta todos los posibles procesos físicos que en ella tienen lugar. Adoptando un modelo atmosférico específico, hemos estudiado el proceso de recombinación dielectrónica de metales como MgII y FeII, teniendo en cuenta la posible influencia de la opacidad del medio en el flujo emitido.

Cruzado, A.; Ringuelet, A.; di Rocco, H.

430

An erupted migmatite from Cerro del Hoyazo, SE Spain  

Microsoft Academic Search

The almandine-bearing biotite-cordierite-labradorite dacite of the Cerro del Hoyazo is part of the Neogene volcanic range\\u000a in SE Spain, extending roughly from Cabo de Gata to Cartagena.\\u000a \\u000a About 1 vol. % of the lava consists of rock inclusions, measuring over 1 cm, made up of almandine-biotite-sillimanite gneiss,\\u000a quartz-cordierite gneiss and spinel-cordierite rock. On the ground of their abundance, chemical composition,

H. P. Zeck

1970-01-01

431

X-ray detection of Nova Del 2013 with Swift  

NASA Astrophysics Data System (ADS)

Continuous X-ray monitoring by Swift of Nova Del 2013 (see CBET #3628) shows an increase of X-ray emission at the source location compared to previous observations (ATEL #5283, ATEL #5305) during a 3.9 ksec observation at UT 2013-08-22 12:05. With the XRT instrument operating in window timing mode, 744 counts were extracted from a 50 pixel long source region and 324 counts from a similar box for a background region, resulting in a 13-sigma detection with a net count rate of 0.11±0.008 counts/sec.

Castro-Tirado, Alberto J.; Martin-Carrillo, Antonio; Hanlon, Lorraine

2013-08-01

432

Optical photometry and spectroscopy of Nova Del 2013  

NASA Astrophysics Data System (ADS)

We report optical BV photometry and spectroscopy of Nova Del 2013, carried out between August 14.88 UT and August 15.08 UT. Using a 60 cm Cassegrain telescope at the Nicolaus Copernicus University Observatory (Torun, Poland) we estimated the V brightness of the Nova to be 6.31+/-0.02 mag and 6.18+/-0.03 mag on Aug. 14.94 UT and Aug. 15.02 UT respectively. HD 194113 (F2, V=8.00 mag) was used as a comparison star.

Tomov, T.; Ilkiewicz, K.; Swierczynski, E.; Belcheva, M.; Dimitrov, D.

2013-08-01

433

Tireoidite auto-imune bociogenica. Aspectos do diagnostico clinico e laboratorial. (Autoimmune thyroiditis goitrogenic. Aspects of clinical and laboratorial diagnosis).  

National Technical Information Service (NTIS)

To asses the accuracy achieved by the A.C.A.T. and other clinical and laboratorial criterion in the diagnoses of T.A.I.B. we investigated twenty patients with goiter and antimicrossomal antibodies titres of 1/1.600 or more. Analysing the parameters useful...

H. F. Z. Costa

1986-01-01

434

Recoleccion de Muestras para Diagnostico de Enfermedades de los Animales (Collection and Delivery of Samples for Diagnosis of Animal Diseases).  

National Technical Information Service (NTIS)

The manual provides instructions for collecting and handling samples for diagnosis of 65 animal diseases. Livestock reviewed included sheep, beef cattle, horses, swine, dogs, poultry, alpacas. Also reviews analysis for parasites.

C. L. Ortecho M. Vasquez C. Marchinares

1967-01-01

435

Crueldad, simulacion, absurdo y amenaza: Barbarie del drama moderno y tradicion hermetica en los esperpentos de Ramon del Valle-Inclan  

Microsoft Academic Search

The purpose of this dissertation is to demonstrate that the esperpentos by the Spanish playwright Ramón del Valle-Inclán (1866–1936), represent a culminating moment of theatrical precepts of modern European drama, while perpetuating the ancient esoteric traditions of the Iberian Peninsula. Focusing on four plays—Los cuernos de Don Friolera (1920), Luces de Bohemia (1921), Las galas del difunto (1926) y La

Barbara Safille

2004-01-01

436

DISEÑO DE UNA PLANTA PILOTO PARA EL TRATAMIENTO DEL RESIDUAL DE UNA SALINA  

Microsoft Academic Search

En el proceso de extracción de cloruro de sodio a partir de agua de mar queda una salmuera residual rica en sales de sodio y magnesio que al ser tratadas químicamente y al ser evaporada permite recuperar aproximadamente el 75% del cloruro de sodio que queda en dicho residual, lo que puede reducir la contaminación ambiental del litoral y generar

Mariana Estela Colombat Rodríguez; Amada Lissett Colombat Rodríguez

2011-01-01

437

ALERTINF: MODELLO DI PREVISIONE DELLE EMERGENZE PER IL CONTROLLO DELLE INFESTANTI DEL MAIS IN VENETO  

Microsoft Academic Search

La gestione delle infestanti è una pratica fondamentale nella coltivazione del mais. Il tempo di comparsa delle malerbe influenza la competizione tra infestante e specie coltivata determinando l'entità del danno che le malerbe possono provocare in termini di resa della coltura. La capacità di prevedere le emergenze delle malerbe può aiutare ad ottimizzare i tempi di controllo, può aumentare l'efficacia

Roberta Masin; Giuliano Cacciatori; Maria Clara Zuin; Giuseppe Zanin

438

Estrategia para potenciar el desarrollo del talento en los escolares de la educación primaria  

Microsoft Academic Search

El desarrollo del talento en el mundo es una polémica que cobra auge en la actualidad. Cuba, país en vía de desarrollo brinda a este tema especial atención. Por su importancia y novedad, la presente investigación se centra en cómo potenciar el desarrollo del talento en la Educación Primaria. Con un enfoque histórico cultural la estrategia propuesta como vía de

Niurkis Lozano Cabrera

2011-01-01

439

ALCANCES Y LIMITACIONES DE LA TEORÍA DEL APEGO Y LA BASE SEGURA  

Microsoft Academic Search

El origen de la teoría del apego se remonta a los trabajos etológicos de Lorenz con patos silvestres. Según la observación de este autor, se notaba en los patos cierto apego entre la madre y sus crías minutos después de los nacimientos; dicho lazo duraría gran parte de la vida biológica del animal (Bowlby, 1986; 1989). Con estas observaciones en

Maximiliano Korstanje

2009-01-01

440

Contrastación del modelo de in versión de Rusbult en una muestra de casados y divorciados  

Microsoft Academic Search

Este estudio examina la capacidad del modelo de in versión propuesto por Rusbult para diferenciar en - tre individuos en relaciones estables e individuos en relaciones inestables, así como la capacidad de las variables del modelo (satisfacción matrimonial, in versión y relaciones alternati vas) para predecir el compromiso y la estabilidad de las relaciones matrimoniales. Los datos sobre las varia

David Martínez-Íñigo

2000-01-01

441

El Instituto Nacional del Cáncer publica nuevo atlas de mortalidad por cáncer  

Cancer.gov

El Instituto Nacional del Cáncer (NCI, por sus siglas en inglés) ha publicado un nuevo atlas, el Atlas de Mortalidad por Cáncer en los Estados Unidos, 1950-94, que muestra los patrones geográficos de las tasas de mortalidad por cáncer durante más de cuatro décadas, en más de 3.000 condados a lo largo del país.

442

61. M.C., photographer June 22, 1951 KLAMATH, DEL NORTE COUNTY, ...  

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

61. M.C., photographer June 22, 1951 KLAMATH, DEL NORTE COUNTY, SECTION A, HIGHWAY 1. DN-1-A #452 NORTHERLY THROUGH KLAMATH FROM STA. 325+50, 6/22/51, M.C. Stamped office copy. - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City, Del Norte County, CA

443

Indicador espacial del metabolismo urbano. Huella Ecológica de la ciudad de Tandil, Argentina  

Microsoft Academic Search

Además de problemas urbanos evidentes -contaminación, residuos, etc.-, existe un problema asociado a la propia dinámica del sistema urbano que es de interés: la apropiación creciente de ecosistemas productivos externos destinados a satisfacer los requerimientos del metabolismo urbano de la ciudad de Tandil, Argentina. Se emplea para su cálculo, la Huella Ecológica (HE) (Rees 1996a; Wackernagel 1996) que permite evaluar

Elsa Marcela Guerrero; Fernando Guiñirgo

2008-01-01

444

Experience the magic of light and color: outreach activity by Universidad del Valle student chapter  

Microsoft Academic Search

During 2007, the Universidad del Valle Student Chapter presented a proposal for developing an educational outreach activity for children from an underprivileged zone to the Optical Society of America Foundation (OSAF) and to SPIE. The activity was carried out jointly by OSA and SPIE Universidad del Valle Student Chapters in the hillsides of Santiago de Cali, in a zone known

Claudia Valdes; Camilo Reyes; Alberto Osorio; Efrain Solarte

2010-01-01

445

Quattordici Punti di accordo con i rapporti ufficiali governativi sulla distruzione del World Trade Center  

Microsoft Academic Search

I rapporti di FEMA e NIST contengono la versione ufficiale sulla distruzione del World Trade Center, avvenuta l'11 settembre 2001. In questa lettera vogliamo porre le basi per una discussione costruttiva e chiarificatrice, focalizzandoci sui punti di comune accordo con FEMA e NIST, e refutando nel contempo diverse credenze errate sui crolli del WTC. L'undici settembre 2001 le Torri Gemelle

Steven E. Jones; Frank M. Legge; Kevin R. Ryan; Anthony F. Szamboti; James R. Gourley

446

Estudio del Selenio y la Vitamina E para Prevenir el Cáncer (SELECT): preguntas y respuestas  

Cancer.gov

SELECT sigue evaluando los efectos de los suplementos aunque los participantes ya no toman los suplementos del estudio. El Comité de Vigilancia de Datos y Seguridad del estudio, que opera con plena independencia, descubrió que el selenio y la vitamina E, tomados solos o juntos por un promedio de 5 años, no impide el cáncer de próstata.

447

Estudio del Selenio y la Vitamina E para Prevenir el Cáncer (SELECT)  

Cancer.gov

SELECT sigue evaluando los efectos de los suplementos aunque los participantes ya no toman los suplementos del estudio. El Comité de Vigilancia de Datos y Seguridad del estudio, que opera con plena independencia, descubrió que el selenio y la vitamina E, tomados solos o juntos por un promedio de 5 años y medio, no impiden el cáncer de próstata.

448

33 CFR 334.110 - Delaware Bay off Cape Henlopen, Del.; naval restricted area.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Delaware Bay off Cape Henlopen, Del.; naval...RESTRICTED AREA REGULATIONS § 334.110 Delaware Bay off Cape Henlopen, Del.; naval...Beginning at a point on the south shore of Delaware Bay at longitude 75°06â²12â³; thence to latitude...

2013-07-01

449

33 CFR 162.200 - Marina del Rey, Calif.; restricted area.  

Code of Federal Regulations, 2010 CFR

...Waters 2 2010-07-01 2010-07-01 false Marina del Rey, Calif.; restricted area. 162.200 Section 162.200...INLAND WATERWAYS NAVIGATION REGULATIONS § 162.200 Marina del Rey, Calif.; restricted area. (a) The area ....

2010-07-01

450

33 CFR 162.200 - Marina del Rey, Calif.; restricted area.  

Code of Federal Regulations, 2010 CFR

...Waters 2 2009-07-01 2009-07-01 false Marina del Rey, Calif.; restricted area. 162.200 Section 162.200...INLAND WATERWAYS NAVIGATION REGULATIONS § 162.200 Marina del Rey, Calif.; restricted area. (a) The area ....

2009-07-01

451

C.35delG/ GJB2 and del(GJB6-D13S1830) mutations in Croatians with prelingual non-syndromic hearing impairment  

PubMed Central

Background C.35delG/GJB2 mutation is the most frequent genetic cause of deafness in Caucasians. Another frequent mutation in some Caucasian populations is del(GJB6-D13S1830). Both GJB2 and GJB6 genes belong to the same DFNB1 locus and when the two mutations are found in combination in a hearing-impaired person, a digenic pattern of inheritance is suggested. Methods We examined 63 Croatian subjects (25 familial and 38 sporadic cases) with prelingual non-syndromic hearing impairment by polymerase chain reaction for the presence of the c.35delG/GJB2 and the del(GJB6-D13S1830) mutations. Results Of the 63 unrelated hearing-impaired subjects, the mutation c.35delG/GJB2 was found in 21 subjects (33.3%). In 5 of them the mutation was found in the heterozygous state, all of them being compound heterozygotes, as sequencing revealed a second mutation within the coding region of the gene in 3 subjects, and a splice site mutation in 2 subjects. The del(GJB6-D13S1830) mutation was not found in the investigated hearing-impaired Croatian subjects. Conclusion Our results contribute to the knowledge of geographic distribution and population genetics of the GJB2 and GJB6 mutations in the Europeans.

Medica, Igor; Rudolf, Gorazd; Balaban, Manuela; Peterlin, Borut

2005-01-01

452

33 CFR 162.40 - Inland waterway from Delaware River to Chesapeake Bay, Del. and Md. (Chesapeake and Delaware Canal).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Inland waterway from Delaware River to Chesapeake Bay, Del. and Md. (Chesapeake and Delaware Canal). 162.40 Section 162...REGULATIONS § 162.40 Inland waterway from Delaware River to Chesapeake Bay, Del. and...

2013-07-01

453

33 CFR 207.100 - Inland waterway from Delaware River to Chesapeake Bay, Del. and Md. (Chesapeake and Delaware...  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Inland waterway from Delaware River to Chesapeake Bay, Del. and Md. (Chesapeake and Delaware Canal); use, administration, and... § 207.100 Inland waterway from Delaware River to Chesapeake Bay, Del. and...

2013-07-01

454

33 CFR 207.100 - Inland waterway from Delaware River to Chesapeake Bay, Del. and Md. (Chesapeake and Delaware...  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Inland waterway from Delaware River to Chesapeake Bay, Del. and Md. (Chesapeake and Delaware Canal); use, administration, and... § 207.100 Inland waterway from Delaware River to Chesapeake Bay, Del. and...

2010-07-01

455

Disruption of cytokeratin-8 interaction with F508del-CFTR corrects its functional defect  

PubMed Central

We have previously reported an increased expression of cytokeratins 8/18 (K8/K18) in cells expressing the F508del mutation of cystic fibrosis transmembrane conductance regulator (CFTR). This is associated with increased colocalization of CFTR and K18 in the vicinity of the endoplasmic reticulum, although this is reversed by treating cells with curcumin, resulting in the rescue of F508del-CFTR. In the present work, we hypothesized that (i) the K8/K18 network may interact physically with CFTR, and that (ii) this interaction may modify CFTR function. CFTR was immunoprecipitated from HeLa cells transfected with either wild-type (WT) CFTR or F508del-CFTR. Precipitates were subjected to 2D-gel electrophoresis and differential spots identified by mass spectrometry. K8 and K18 were found significantly increased in F508del-CFTR precipitates. Using surface plasmon resonance, we demonstrate that K8, but not K18, binds directly and preferentially to the F508del over the WT human NBD1 (nucleotide-binding domain-1). In vivo K8 interaction with F508del-CFTR was confirmed by proximity ligation assay in HeLa cells and in primary cultures of human respiratory epithelial cells. Ablation of K8 expression by siRNA in F508del-expressing HeLa cells led to the recovery of CFTR-dependent iodide efflux. Moreover, F508del-expressing mice topically treated with K8-siRNA showed restored nasal potential difference, equivalent to that of WT mice. These results show that disruption of F508del-CFTR and K8 interaction leads to the correction of the F508del-CFTR processing defect, suggesting a novel potential therapeutic target in CF.

Colas, Julien; Faure, Grazyna; Saussereau, Emilie; Trudel, Stephanie; Rabeh, Wael M.; Bitam, Sara; Guerrera, Ida Chiara; Fritsch, Janine; Sermet-Gaudelus, Isabelle; Davezac, Noelie; Brouillard, Franck; Lukacs, Gergely L.; Herrmann, Harald; Ollero, Mario; Edelman, Aleksander

2012-01-01

456

High precision ages from the Torres del Paine Intrusion, Chile  

NASA Astrophysics Data System (ADS)

The upper crustal bimodal Torres del Paine Intrusion, southern Chile, consists of the lower Paine-Mafic- Complex and the upper Paine-Granite. Geochronologically this bimodal complex is not well studied except for a few existing data from Halpern (1973) and Sanchez (2006). The aim of this study is to supplement the existing data and to constrain the age relations between the major magmatic pulses by applying high precision U-Pb dating on accessory zircons and 40Ar/39Ar-laser-step-heating-ages on biotites from the Torres del Paine Intrusion. The magmatic rocks from mafic complex are fine to medium-grained and vary in composition from quartz- monzonites to granodiorites and gabbros. Coarse-grained olivine gabbros have intruded these rocks in the west. The granitic body is represented by a peraluminous, biotite-orthoclase-granite and a more evolved leucocratic granite in the outer parts towards the host-rock. Field observations suggest a feeder-zone for the granite in the west and that the granite postdates the mafic complex. Two granite samples of the outermost margins in the Northeast and South were analyzed. The zircons were dated by precise isotope-dilution U-Pb techniques of chemically abraded single grains. The data are concordant within the analytical error and define weighted mean 206/238U ages of 12.59 ± 0.03 Ma and 12.58 ± 0.01 Ma for the two samples respectively. A 40Ar/39Ar-age for the second sample yield a date of 12.37 ± 0.11 Ma. Three 40Ar/39Ar -ages of biotites were obtained for rocks belonging to the mafic complex. A hbl-bio- granodiorite from the central part, approximately 150 m below the subhorizontal contact with the granite, gives an age of 12.81 ± 0.11 Ma. A hbl-bio-granodiorite and an olivine-gabbro west of the feeder-zone date at 12.42 ± 0.14 Ma and 12.49 ± 0.11 Ma, respectively. The obtained older age of 12.81 Ma for the granodiorite in the central part is consistent with structural relationships of brittle fracturing of the mafic complex by the granite and we conclude that some parts of the mafic complex were emplaced before the granite. The well defined 206/238U-age for zircons and the slightly younger 40Ar/39Ar -ages for biotites of both rock suites show that emplacement and cooling of the Torres del Paine Intrusion took place in a relatively short time-frame. Halpern, 1973, Geological Society of America Bulletin, 84/7: 2407-2422. Sanchez et.al., 2006. V SSAGI, Punta del Este, April 2006.

Michel, J.; Baumgartner, L.; Cosca, M.; Ovtcharova, M.; Putlitz, B.; Schaltegger, U.

2006-12-01

457

Numerical Kähler-Einstein Metric on the Third del Pezzo  

NASA Astrophysics Data System (ADS)

The third del Pezzo surface admits a unique Kähler-Einstein metric, which is not known in closed form. The manifold’s toric structure reduces the Einstein equation to a single Monge-Ampère equation in two real dimensions. We numerically solve this nonlinear PDE using three different algorithms, and describe the resulting metric. The first two algorithms involve simulation of Ricci flow, in complex and symplectic coordinates respectively. The third algorithm involves turning the PDE into an optimization problem on a certain space of metrics, which are symplectic analogues of the “algebraic” metrics used in numerical work on Calabi-Yau manifolds. Our algorithms should be applicable to general toric manifolds. Using our metric, we compute various geometric quantities of interest, including Laplacian eigenvalues and a harmonic (1,1)-form. The metric and (1,1)-form can be used to construct a Klebanov-Tseytlin-like supergravity solution.

Doran, Charles; Headrick, Matthew; Herzog, Christopher P.; Kantor, Joshua; Wiseman, Toby

2008-09-01

458

Renewable energy load assessment for Boquillas Del Carmen Coahuila, Mexico  

SciTech Connect

This report outlines the estimates that were made in 1992 of the potential load requirements for Boquillas del Carmen, a small Mexican village on the northern border of the state of Coahuila, Mexico near Big Bend National Park in southern Texas. The study was made to help determine the possibility that village might be electrified by solar or wind energy. Various estimates of are given of the potential load based on estimates ranging from basic use of lights, radio, television, and small household appliances to microwave ovens, refrigerators, and direct evaporative coolers. The low-energy consumption case was estimated to be at 23.0 kWh/month per residence per month, and the high-energy consumption case (with cooling) was 140.7 kWh/month per residence. On average, the typical residence is occupied by five individuals.

Foster, R. [Southwest Technology Development Institute, Las Cruces, NM (United States)

1995-08-01

459

Near-IR Photometry of Nova Del 2013  

NASA Astrophysics Data System (ADS)

Subjects: Infra-Red, Nova We report Near-IR photometry of Nova Del 2013 taken with the 0.76-m infrared telescope at the University of Minnesota's O'Brien Observatory (Marine on St. Croix, Minnesota, USA). RIJHKLM photometry were obtained on August 21.17 and 23.13 UT using an AsSi bolometer. Vega (alpha Lyrae) was used as the standard star. Our photometry show: August 21.17 UT: R = 5.1 +/- 0.1, I = 4.6 +/- 0.1, J = 4.6 +/- 0.1, H = 4.1 +/- 0.1, K = 3.9 +/- 0.1, L = 2.7 +/- 0.2, M = +2.2 +/- 0.2.

Cass, C. A.; Carlon, L. R.; Corgan, T. D.; Dykhoff, A. D.; Gehrz, D. R.; Shenoy, P. D.

2013-08-01

460

Impacto de las Tecnologías de la Información y las Comunicaciones (TIC) en el desarrollo y la competitividad del país  

Microsoft Academic Search

La primera parte de este estudio caracteriza al sector de telecomunicaciones en Colombia, comparando a Colombia con otros países y regiones del mundo, mostrando la evolución de algunos de los principales indicadores de telecomunicaciones. En la segunda parte se hacen estimaciones cuantitativas del impacto socioeconómico del sector en la economía colombiana, a través de dos herramientas: la metodología insumo-producto y

Juan Benavides; Felipe Castro; Lina Devis; Mauricio Olivera

2011-01-01

461

EL PAPEL DE LOS AUXILIARES DE LA JUSTICIA EN VÍAS DE LA IMPLEMENTACIÓN DEL SISTEMA ACUSATORIO EN PANAMÁ  

Microsoft Academic Search

Este artículo trata sobre el papel preponderante que juegan los Auxiliares de la Justicia que cobra mayor relevancia dentro del engranaje del modelo del Sistema Acusatorio, en los Procesos Orales, garantista en Contra posición con el actual Sistema Inquisitivo destacando el trabajo, capacidad y preponderancia de Estos colaboradores muchas veces anónimos en el Sistema actual, pero que serán de suma

Ivanovha Lamela

2011-01-01

462

Deglacial palaeoclimate at Puerto del Hambre, subantarctic Patagonia, Chile  

NASA Astrophysics Data System (ADS)

The primary objective of this study is to further substantiate multistep climatic forcing of late-glacial vegetation in southern South America. A secondary objective is to establish the age of deglaciation in Estrecho de Magallanes-Bahía Inútil. Pollen assemblages at 2-cm intervals in a core of the mire at Puerto del Hambre (53°3621S, 70°5553W) provide the basis for reconstructing the vegetation and a detailed account of palaeoclimate in subantarctic Patagonia. Chronology over the 262-cm length of core is regulated by 20 AMS radiocarbon dates between 14 455 and 10 089 14C yr BP. Of 13 pollen assemblage zones, the earliest representing the Oldest Dryas chronozone (14 455-13 000 14C yr BP) records impoverished steppe with decreasing frequencies and loss of southern beech (Nothofagus). Successive 100-yr-long episodes of grass/herbs and of heath (Empetrum/Ericaceae) before 14 000 14C yr BP infer deglacial successional communities under a climate of increased continentality prior to the establishment of grass-dominated steppe. The Bølling-Allerød (13 000-11 000 14C yr BP) is characterised by mesic grassland under moderating climate that with abrupt change to heath dominance after 12 000 14C yr BP was warmer and not as humid. At the time of the Younger Dryas (11 000-10 000 14C yr BP), grass steppe expanded with a return of colder, more humid climate. Later, with gradual warming, communities were invaded by southern beech. The Puerto del Hambre record parallels multistep, deglacial palaeoclimatic sequences reported elsewhere in the Southern Andes and at Taylor Dome in Antarctica. Deglaciation of Estrecho de Magallanes-Bahía Inútil is dated close to 14 455 14C yr BP, invalidating earlier dates of between 15 800 and 16 590 14C yr BP.

Heusser, Calvin J.; Heusser, Linda E.; Lowell, Thomas V.; Moreira M., Andrés; Moreira M., Simón

2000-02-01

463

[Epidemiology of dog bite lesions in Tierra del Fuego, Argentina].  

PubMed

The coexistence between man and dog has resulted in mutual benefits during thousands of years, nevertheless some problems have recently arisen where bite injuries have an important role. The aim of this work was to describe the epidemiological characteristics of dog bite lesions which occurred during a year in Tierra del Fuego. A descriptive observational, transversal study of patients who were admitted with dog bite injuries to clinic and pediatric emergency services of hospitals and health centers was carried out between 3/1/05 and 3/1/06. A total of 382 records were made. The children group represents 49.5%. The group between 5 and 9 year-old was the most affected (44.4%; IC95% 37.2-51.8). In the adult group, that between 15 and 24 year-old was the most affected (29.5%; IC95% 23.2-36.5). More lesions were registered in men (57.6%) than in women (42.4%) (chi2 = 8.6, p = 0.003). During spring and summer months, 56.5% of the lesions were registered. A 72.8% of the incidents occurred on the public highway. Dogs of big size were responsible of 49.7% (IC95% 44.6-54.9) of the injuries. The 89.8% of the incidents were caused by another person's dog. Of the lesions, 55.8% (IC95% 50.6-60.8) were registered in lower extremities and 11% (IC95% 8.1-14.7) in head and neck. These data show that dog bite lesions affect the health and impact in the quality of life of the population of Tierra del Fuego, Argentina. PMID:18416313

Zanini, Fabián; Padinger, Patricia; Elissondo, María C; Pérez, Héctor

2008-01-01

464

Switching EKF technique for rotor and stator resistance estimation in speed sensorless control of IMs  

Microsoft Academic Search

High performance speed sensorless control of induction motors (IMs) calls for estimation and control schemes that offer solutions to parameter uncertainties as well as to difficulties involved with accurate flux\\/velocity estimation at very low and zero speed. In this study, a new EKF based estimation algorithm is proposed for the solution of both problems and is applied in combination with

Murat Barut; Seta Bogosyan; Metin Gokasan

2007-01-01

465

Estimating the remaining service life of asphalt-mica stator insulation  

Microsoft Academic Search

Synchronous generators were manufactured with asphalt bonded, mica flake insulation from 1917 to the 1950s. There is a large fleet, perhaps two thousand, of these machines still in service today. This paper presents the results of a well documented series of field tests, many to failure, on 20 asphalt-mica insulated fossil fuel and hydroelectric synchronous generators on the American Electric

J. E. Timperley; J. R. Michalec

1994-01-01

466

An unsupervised, on-line system for induction motor fault detection using stator current monitoring  

Microsoft Academic Search

A new method for online induction motor fault detection is presented in this paper. This system utilizes artificial neural networks to learn the spectral characteristics of a good motor operating online. This learned spectrum may contain many harmonics due to the load which correspond to normal operating conditions. In order to reduce the number of harmonics which are continuously monitored

R. R. Schoen; B. K. Lin; T. G. Habetler; J. H. Schlag; S. Farag

1995-01-01

467

Induction motors' faults detection and localization using stator current advanced signal processing techniques  

Microsoft Academic Search

The knowledge about fault mode behavior of an induction motor drive system is extremely important from the standpoint of improved system design, protection, and fault-tolerant control. This paper addresses the application of motor current spectral analysis for the detection and localization of abnormal electrical and mechanical conditions that indicate, or may lead to, a failure of induction motors. Intensive research

Mohamed El Hachemi Benbouzid; Michelle Vieira; C. Theys

1999-01-01

468

Rotor and Stator Stresses During Starting of Induction Motors Used in Cement Industry Applications  

Microsoft Academic Search

Induction motors drive a variety of applications in a cement manufacturing plant such as kilns, crushers, ID fans, separators, cooler fans etc. Motor manufacturers serving cement industry needs are often faced with challenging tasks of designing motors suitable for various operating conditions and requirements which have to be not only reliable, but also cost competitive. During starting, several transient thermal

Radu Curiac; Sumit Singhal

2009-01-01

469

Indicator for bearing fault detection in asynchronous motors using stator current spectral analysis  

Microsoft Academic Search

This paper deals with the application of motor current spectral analysis for the detection of artificially damaged rolling bearings in asynchronous machine. Vibration monitoring of mechanical characteristic frequencies related to the bearings is widely used to detect faulty operations. However, vibration measurement is expensive and can not always be performed. An alternative is to base the monitoring on the available

Baptiste Trajin; Jeremi Regnier; Jean Faucher

2008-01-01

470

Effect of the Position and the Number of Broken Bars on Asynchronous Motor Stator Current Spectrum  

Microsoft Academic Search

The asynchronous motor has an interest in strong powers applications requiring speed variation. Even if it is robust, it is not saved by electrical or mechanical defects. Among rotor defects, we can quote a fissure or a total break of bar, a rupture of end ring circuit, an eccentricity of the rotor axis... In this paper, we use a technique

Arezki Menacer; Sandrine Moreau; Abdelhamid Benakcha; Mohamed Said Nait Said

2006-01-01

471

Transient Voltage Distribution in Stator Winding of Electrical Machine Fed from a Frequency Converter.  

National Technical Information Service (NTIS)

Standard induction motors are exposed to steep fronted, non-sinusoidal voltages when fed from frequency converters. These wave patterns can be destructive to the insulation. The aim of this work is to describe methods of predicting the magnitude and distr...

B. S. Oyegoke

1997-01-01

472

Induction machine stator fault on-line diagnosis based on LabVIEW environment  

Microsoft Academic Search

The benefits of machine condition monitoring have been widely recognized as superior with respect to other alternative maintenance approaches. Condition monitoring is an operational strategy for machine integrity assessment, fault identification and life extension. The cost-benefit ratio will be reduced in progress owing to the commercial diagnostic environment availability. This paper presents the implementation of a diagnostic procedure to detect

L Collamatit; F. Filippetti; G. Franceschini; S. Pirani; C. Tassoni

1996-01-01

473

Evaluation of experimental permanent magnet brushless motor utilizing new magnetic material for stator teeth core  

Microsoft Academic Search

A magnetic characteristic measurement, a motor characteristic prediction, and an experimental evaluation of motors using various magnetic materials were performed to identify features of various magnetic materials, which are used in a motor core as a magnetic material. The results are as follows: (1) Motor with amorphous metal sheet showed very high motor efficiency, with its high permeability and extremely

Y. Enomoto; M. Ito; H. Koharagi; R. Masaki; S. Ohiwa; C. Ishihara; M. Mita

2005-01-01

474

Acoustic Benefits of Stator Sweep and Lean for a High Tip Speed Fan.  

National Technical Information Service (NTIS)

A model high-speed fan stage was acoustically tested in the NASA Glenn 9- by 15-Foot Low Speed Wind Tunnel at takeoff/approach flight conditions. The fan was designed for a corrected rotor tip speed of 442 m/s (1450 ft/s), and had a powered core, or boost...

R. P. Woodward J. A. Gazzaniga L. J. Bartos C. E. Hughes

2002-01-01

475

STATOR-ROTOR AEROELASTIC INTERACTION FOR THE TURBINE LAST STAGE IN 3D TRANSONIC FLOW  

Microsoft Academic Search

A three-dimensional numerical analysis for aerodynamic unsteady forces and flutter parameters of the last stage steam turbine\\u000a 13K215 rotor blades have been presented. The low frequency excitation was simulated for a 94 rotating blades with 54 nozzles.\\u000a It was assumed that the pressure behind the rotor blades is changing in the circumferential direction. The flutter parameters\\u000a of this stage were

Romuald Rzadkowski; Vitaly Gnesin; Luba Kolodyazhnaya

476

A study on power factor of linear oscillatory motor with two separated stators  

Microsoft Academic Search

Based on equivalent linear treatment of the gas force load, the mathematical model of motor system was established. Then, the effect of gas force load and operating frequency on the power factor was investigated. The predicted analysis was validated by corresponding experimental and simulated results. The results shown that maximum power factor is obtained when the operating frequency near the

Yu Ming-hu; Ye Yun-yue; Lu Qin-fen; Xia Yong-ming

2009-01-01

477

Fault tolerant IPMS motor drive based on adaptive backstepping observer with unknown stator resistance  

Microsoft Academic Search

This work considers the problem of designing a fault tolerant system for IPMS motor drive subject to current sensor fault. To achieve this goal, two control strategies are considered. The first is based on field oriented control and a developed adaptive backstepping observer which simultaneously are used in the case of fault-free. The second approach proposed is concerned with fault

H. Nademi; F. Tahami; M. Rezaei

2008-01-01

478

Detection of Slot Discharges in High-Voltage Stator Windings During Operation  

Microsoft Academic Search

A modified slot discharge detection method, which permits tests without Shutting down the machine or using auxilliary high-voltage test equipment, was investigated. The method involves connection of frequency sensitive equipment across all or part of the ntral impedance. Tests on eight vertical water wheel generators in the range of 20,000- to 40,000-kva capacity indicate that the method is generally applicable

John S. Johnson; Mead Warren

1951-01-01

479

Vib-Code to Simulate 3-D Stator/Rotor Flow in Axial Turbines.  

National Technical Information Service (NTIS)

The numerical simulation of the flow through an axial turbine stage using a finite volume Navier-Stokes method is reported. The methods for selecting the optimal grid and the grid generation are outlined. Numerous improvements are integrated into an exist...

A. Hilgenstock

1992-01-01

480

Stator Current Frequency Spectra and Torque Pulsations in Induction Machines with Rotor Convertor Cascades.  

National Technical Information Service (NTIS)

In this thesis a mathematical model has been implemented on a computer and used to calculate the harmonic components of the currents and electrodynamic torque in an induction machine equipped with a convertor connected to the rotor winding. The harmonics ...

J. Hylander

1986-01-01

481

Turbulent heat transfer on the stationary disk in a rotor–stator system  

Microsoft Academic Search

A combined numerical and experimental study was performed to determine the turbulent heat transfer on a stationary disk, which is situated in a close distance from a rotating disk. The RNG k–? model and the steady-state liquid crystal technique were employed respectively in the numerical simulation and the experiment. In the range of the rotational Reynolds number from 1.42×105 to

Z. X. Yuan; N. Saniei; X. T. Yan

2003-01-01

482

Larval host plant affects fitness consequences of egg size variation in the seed beetle Stator limbatus  

Microsoft Academic Search

Egg size variation often has large effects on the fitness of progeny in insects. However, many studies have been unable to detect an advantage of developing from large eggs, suggesting that egg size variation has implications for offspring performance only under adverse conditions, such as during larval competition, periods of starvation, desiccation, or when larvae feed on low-quality resources. We

Charles W. Fox; Timothy A. Mousseau

1996-01-01

483

Travelling wave ultrasonic motors, Part I: Working principle and mathematical modelling of the stator  

Microsoft Academic Search

Travelling wave ultrasonic motors have recently been attracting considerable attention: they may possibly soon replace-at least in certain areas-small electromagnetic motors. This development has been made possible by recent advances in power electronics, material research and digital control, which allow utilization of the piezoelectric effect for low power motors. In these motors the mechanical energy is generated with frequencies of

P. Hagedorn; J. Wallaschek

1992-01-01

484

Travelling Wave Ultrasonic Motors, Part II: A Numerical Method For The Flexural Vibrations Of The Stator  

Microsoft Academic Search

A finite difference scheme is used to calculate the forced transverse vibrations of thin annular plates with radially varying thickness. Under the assumption of harmonic motion, the governing partial differential equation reduces to a system of ordinary differential equations with variable coefficients. The numerical scheme that solves this system for various boundary conditions is successfully tested vs. known analytical solutions,

P. Hagedorn; J. Wallaschek; W. Konrad

1993-01-01

485

Finite element analysis of Brushless Doubly-Fed Machine under stator winding faults  

Microsoft Academic Search

In this paper the finite element model of the Brushless Doubly-Fed Machine is presented. A magnetodynamic finite element model allowing the simulation of the healthy and faulted machine with its special rotor topology is extracted and simulated. To verify the validation of the proposed model the results are compared with couple circuit model, which used generalized harmonic theory. Keywords-Brushless Doubly-Fed

Hamed Gorginpour; Behzad Jandaghi; Hashem Oraee

2011-01-01

486

Dynamic model for Brushless Doubly-Fed Machine with stator winding faults  

Microsoft Academic Search

In this paper, a detailed analytical model for dynamic analysis of the Brushless Doubly-Fed Machine is presented. The model is capable to predict the machine behavior under different modes of operation including: simple induction mode, cascade mode and synchronous mode, both with and without winding faults and unbalanced excitations. The proposed approach employs the basic principles of the generalized harmonic

Hamed Gorgin; Pedram Sotoodeh; Hashem Oraee

2010-01-01

487

Flowfield measurements for a highly turbulent flow in a stator vane passage  

SciTech Connect

Turbine vanes experience high convective surface heat transfer as a consequence of the turbulent flow exiting the combustor. Before improvements to vane heat transfer predictions through boundary layer calculations can be made, an understanding of how the turbulent flow in the inviscid region of the passage reacts as it passes between two adjacent turbine vanes is needed. In this study, a scaled-up turbine vane geometry was used in a low-speed wind tunnel simulation. The test section included a central airfoil with two adjacent vanes. To generate the 20% turbulence levels at the entrance to the cascade, which simulates levels exiting the combustor, an active grid was used. Three-component laser-Doppler velocimeter measurements of the mean and fluctuating quantities were measured in a plane at the vane midspan. Coincident velocity measurements were made to quantify Reynolds shear stress and correlation coefficients. The energy spectra and length scales were also measured to give a complete set of inlet boundary conditions that can be used for numerical simulations. The results show that the turbulent kinetic energy throughout the inviscid region remained relatively high. The surface heat transfer measurements indicated high augmentation near the leading edge as well as the pressure side of the vane as a result of the elevated turbulence levels.

Radomsky, R.W.; Thole, K.A.

2000-04-01

488

Analysis of a disk-type stator for the piezoelectric ultrasonic motor using impedance matrix  

NASA Astrophysics Data System (ADS)

Impedance and admittance matrices of a piezoelectric annular actuator with segmented electrodes are presented for the analysis of the disk-type piezoelectric ultrasonic motors (USM). Equations of motion and the conjugate parameters for the impedance and admittance matrices are derived using the variational principle. In the derivation, the electric field in the piezoelectric layer is assumed to be constant over the area covered by a particular electrode, and the effects of both shear deformation and rotary inertia are taken into account. The resonance and antiresonance frequencies and the vibrating modes are calculated for the various resonance modes and boundary conditions, and the results are compared with those by the three-dimensional finite element methods. They are in excellent agreement with each other. It is expected that the derived impedance matrix can be effectively applied to the analysis and the design of the USM.

Kim, Young H.; Ha, Sung K.

2003-06-01

489

Design, Simulation, and Testing of a Dual Stator-Winding All-Air-Core Compulsator  

Microsoft Academic Search

The focus toward advanced mobile tactical configu- rations for railgun power supplies has resulted in the evolution of five compulsator generations in the past 30 years from iron-core to air-core prototypes. However, the exact air-core field simu- lation and the complicated fabrication technique of an air-core compulsator are not clear enough for researchers. This paper presents a detailed description of

Shaopeng Wu; Shumei Cui; Liwei Song; Weiduo Zhao; Jing Zhang

2011-01-01

490

FISH Analysis for del6q21 and del17p13 in B-cell Chronic Lymphocytic Leukemia in Iranians  

PubMed Central

Background B-cell chronic lymphocytic leukemia (B-CLL) is the most common leukemia in the Western world. Major progress has been made in assessing typical chromosomal abnormalities and recognition of the correlation of these chromosomal abnormalities with laboratory features and clinical course of the disease. The most frequent genomic changes are deletions at 13q14, 11q22-23 and 17p13 and trisomy of chromosome 12. Objectives The aim of this study was to investigate the frequency of chromosomal aberrations in B-CLL patients’ peripheral blood and/or bone marrow using a molecular cytogenetic method, interphase fluorescence in situ hybridization (I-FISH) and to evaluate the correlation between these genomic changes and clinical findings. Patients and Methods I-FISH analyses were performed on bone marrow and blood samples of 66 B-CLL patients. Results Deletion of 17p13 was found in 11 (16.6%) and deletion 6q21 was present in 5 (7.5%). Statistical analyses were performed to investigate the correlation of these molecular-cytogenetic findings with family history, Rai staging and CD38 marker. No clear differences in distribution was noted for del17p13 and del6q21 among patients with and without family history, and no direct correlation was noted between these genomic changes and CD38 marker, but the correlation of del17p13 and Rai stage was significant. There was a high frequency of Rai stage II within del17p13 patients. Conclusions It was demonstrated that the presence of del6q21 in B-CLL patients indicates poor prognosis and on the contrary, presence of del17p13 points at the good prognostic value of the disease.

Teimori, Hossein; Ashoori, Saeede; Akbari, Mohamad Taghi; Mojtabavi Naeini, Marjan; Hashemzade Chaleshtori, Morteza

2013-01-01

491

33 CFR 162.35 - Channel of Christina River, Del.; navigation.  

Code of Federal Regulations, 2013 CFR

...Christina River, Del.; navigation. (a) That vessels of over 20 tons capacity, propelled by machinery, shall not proceed at any time within the limits of these waters at a greater speed than 8 statute miles per...

2013-07-01

492

Intestinal Parasites of Man in Agusan del Norte, Philippines with Emphasis on Schistosomiasis and Capillariasis.  

National Technical Information Service (NTIS)

A total of 1,920 fecal specimens from residents of seven villages in Agusan del Norte Province, Mindanao, Philippines were examined for schistosomes and common intestinal parasites. Schistosoma japonicum eggs were found in 14% of the samples. Infections i...

W. P. Carney R. Nocun A. G. Vergel I. Pagaran A. Mercado

1987-01-01

493

Notes on the Geochemical Survey in Zamboanga Del Norte - Misamis Occidental, Mindanao, Philippines.  

National Technical Information Service (NTIS)

Stream sediment and panned heavy mineral surveys were conducted in Zamboanga del Norte and Misamis Occidental provinces in northwestern Mindanao. A total of 70 stream sediments and 64 panned heavy mineral concentrates were obtained along active streams dr...

G. Santos J. E. Seguis L. Carino P. Escalada L. Antonio

1983-01-01

494

Del Bueno Amends Recall of Queso Fresco Cheese Because of Possible Health Risk  

NASA Website

Del Bueno of Grandview, WA is recalling all size packages of Queso Fresco Fresh Cheese because it has the potential to be contaminated with Listeria monocytogenes, an organism which can cause serious and sometimes fatal infections in young children, ...

495

Elementos para una reforma del sector público en el contexto de una economía de mercado  

Microsoft Academic Search

En este trabajo se propone un conjunto de elementos básicos que deben ser considerados para el diseño de cualquier estrategia de reforma del sector público en el Perú, abordando cuestiones de carácter económico, social, político y de organización institucional.

Claudio Herzka

1996-01-01

496

Geostatistical investigations of rock masses. The Sierra del Medio Case (Argentina).  

National Technical Information Service (NTIS)

The geostatistical tehniques applied for the selection of a minimun fracturation volume in Sierra del Medio allow to quantify and qualify the variability of mechanic characteristics and density of fracture and also the level of reliability in estimations....

J. A. Matar M. A. Sarquis J. P. Girardi G. H. Tabbia

1987-01-01

497

The Ecology and Distribution of Rock-Boring Pelecypods off Del Monte Beach, Monterey, California.  

National Technical Information Service (NTIS)

Divers using SCUBA gear gathered and identified rock-boring pelecypods found in the subtidal outcrops of Monterey silicious shale off Del Monte Beach, Monterey, California. Underwater photographs were taken of all the recognizable species present. A speci...

G. S. Booth

1972-01-01

498

Estudio multiespectral del remanente de supernova W 28  

NASA Astrophysics Data System (ADS)

Se presentan observaciones en continuo de radio con muy alta resolución angular y sensibilidad del remanente de supernova (RSN) W28. Las observaciones fueron realizadas con el interferómetro Very Large Array (Estados Unidos), en las configuraciones C y D, en 1415 y 324 MHz. Por la gran extensión de este remanente (diámetro ~ 1o), las observaciones en 1415 MHz se realizaron en modo mosaico, combinando 48 apuntamientos diferentes en una única imagen. En ambas frecuencias los datos se procesaron con el agregado de observaciones de menor resolución angular, a fin de recuperar información en todas las frecuencias espaciales y obtener estimaciones precisas de densidad de flujo. Las imágenes resultantes muestran por primera vez la presencia de extensiones con forma de arco, cuya naturaleza se investiga. Las observaciones en radio se comparan con una imagen óptica de W28, y con la emisión en rayos X, observada con el satélite ROSAT. Este remanente muestra una clara morfología híbrida, tipo cáscara en frecuencias de radio y de centro lleno en las bandas óptica y de rayos X blandos.

Dubner, G.; Velázquez, P.; Castelletti, G.

499

Paso del Norte ozone study VOC measurements, 1996  

SciTech Connect

The results of VOC determinations of ambient air samples collected at surface air quality monitoring sites and near sources of interest on the US and Mexican side of the border during six weeks of the 1996 Paso del Norte Ozone Study are reported. Carbonyl samples were collected on DNPH impregnated cartridges at three surface sites and analyzed by HPLC to quantify 13, C-1 to C-8 species. Whole air samples were collected in electro-polished stainless steel canisters which were returned to laboratory for determination of C-2 to C-10+ hydrocarbons by cryogenic preconcentration capillary gas chromatography with flame ionization detection (gc-fid). Several sources were sampled: rush hour traffic, propane-powered bus exhaust, automobile paint shop emissions, propane fuel, petroleum refinery, and industrial manufacturing site. Spatial and temporal characteristics of VOC species concentrations and compositions are presented. Overall surface TNMOC values ranged from 0.1 to 3.4 ppmC with the highest concentrations recorded in the morning at three vehicle-dominated sites, two in Cuidad Juarez and one in downtown El Paso. Toluene in El Paso samples and propane, which is used as a cooking and transportation fuel in Cuidad Juarez, were the most abundant hydrocarbons.

Seila, R.L.; Main, H.; Arriaga, J.L.; Martinez, G.V.; Ramadan, A.B.

1999-01-01

500

Paso del Norte ozone study VOC measurements, 1996  

SciTech Connect

The results of VOC determinations of ambient air samples collected at surface air quality monitoring sites and near sources of interest on the US and Mexican side of the border during six weeks of the 1996 Paso del Norte Ozone Study are reported. Carbonyl samples were collected on DNPH impregnated cartridges at three surface sites and analyzed by HPLC to quantify 13, C-1 to C-8 species. Whole air samples were collected in electro-polished stainless steel canisters which were returned to laboratory for determination of C-2 to C-10+ hydrocarbons by cryogenic preconcentration capillary gas chromatography with flame ionization detection (gc-fid). Several sources were sampled: rush hour traffic, propane-powered bus exhaust, automobile paint shop emissions, propane fuel, petroleum refinery, and industrial manufacturing site. Spatial and temporal characteristics of VOC species concentrations and compositions are presented. Overall surface TNMOC values ranged from 0.1 to 3.4 ppmC with the highest concentrations recorded in the morning at three vehicle-dominated sites, two in Cuidad Juarez and one in downtown El Paso. Toluene in El Paso samples and propane, which is used as a cooking and transportation fuel in Cuidad Juarez, were the most abundant hydrocarbons.

Seila, R.L.; Main, H.; Arriaga, J.L.; Martinez, G.V.; Ramadan, A.B.

1999-11-01