These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Electrical stator  

DOEpatents

An electrical stator of an electromagnetic pump includes first and second spaced apart coils each having input and output terminals for carrying electrical current. An elongate electrical connector extends between the first and second coils and has first and second opposite ends. The connector ends include respective slots receiving therein respective ones of the coil terminals to define respective first and second joints. Each of the joints includes a braze filler fixedly joining the connector ends to the respective coil terminals for carrying electrical current therethrough.

Fanning, Alan W. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

1994-01-01

2

Stator hub treatment study  

NASA Technical Reports Server (NTRS)

The results of an experimental research program to investigate the potential of improving compressor stall margin by the application of hub treatment are presented. Extensive tuft probing showed that the two-stage, 0.5 radius ratio compressor selected for the test was indeed hub critical. Circumferential groove and baffled wide blade angle slot hub treatments under the stators were tested. Performance measurements were made with total and static pressure probes, wall static pressure taps, flow angle measuring instrumentation and hot film anemometers. Stator hub treatment was not found to be effective in improving compressor stall margin by delaying the point of onset of rotating stall or in modifying compressor performance for any of the configurations tested. Extensive regions of separated flow were observed on the suction surface of the stators near the hub. However, the treatment did not delay the point where flow separation in the stator hub region becomes apparent.

Wisler, D. C.; Hilvers, D. E.

1974-01-01

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.

Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

1994-01-01

4

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.

Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

1996-01-01

5

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

6

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

7

Electromagnetic pump stator core  

DOEpatents

A stator core for supporting an electrical coil includes a plurality of groups of circumferentially abutting flat laminations which collectively form a bore and perimeter. A plurality of wedges are interposed between the groups, with each wedge having an inner edge and a thicker outer edge. The wedge outer edges abut adjacent ones of the groups to provide a continuous path around the perimeter. 21 figures.

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

1995-01-17

8

Electromagnetic pump stator coil  

DOEpatents

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.

Fanning, Alan W. (San Jose, CA); Dahl, Leslie R. (Livermore, CA)

1996-01-01

9

Electromagnetic pump stator coil  

DOEpatents

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

10

Laminated electromagnetic pump stator core  

DOEpatents

A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference. This pump is used in nuclear fission reactors. 19 figs.

Fanning, A.W.

1995-08-08

11

Laminated electromagnetic pump stator core  

SciTech Connect

A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference.

Fanning, Alan W. (San Jose, CA)

1995-01-01

12

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

13

Study of controlled diffusion stator blading  

NASA Technical Reports Server (NTRS)

Tests were conducted on a high tip speed, highly loaded front compressor stage having low aspect ratio rotor and stator airfoils. The stator airfoils were designed by the controlled diffusion procedure recently developed by P&WA for designing transonic cascade airfoils. The rotor blades consisted of multiple-circular-arc airfoil sections. The stage had a tip speed of 442 m/sec (1450 ft/sec), a hub/tip ratio of 0.597, a rotor aspect ratio of 1.3, and a stator aspect ratio of 1.45. At design speed the rotor-stator stage achieved an adiabatic efficiency of 89.1% at design flow and pressure ratio. Surge margin was 14%. The stage efficiency exceeded the design goal by 0.6 percentage points. The rotor efficiency was 92.4%, exceeding design by 0.3 percentage points. The controlled diffusion stator demonstrated a lower minimum loss over the multiple-circular-arc stator from the root to 70 percent span. A surge diffusion factor of 0.72 was reached at both the rotor tip and the stator root. The NAS3-22008 program demonstrated its intent: high efficiency and loading levels with low aspect ratio blades and the controlled diffusion stator in the unfavorable front stage environment.

Behlke, R. F.; Brooky, J. D.; Canal, E.

1983-01-01

14

Design and performance of controlled-diffusion stator compared with original double-circular-arc stator  

NASA Technical Reports Server (NTRS)

The capabilities of two stators, one with controlled-diffusion (CD) blade sections and one with double-circular-arc (DCA) blade sections, were compared. A CD stator was designed and tested that had the same chord length but half the blades of the DCA stator. The same fan rotor (tip speed, 429 m/sec; pressure ratio, 1.65) was used with each stator row. The design and analysis system is briefly described. The overall stage and rotor performances with each stator are compared, as are selected blade element data. The minimum overall efficiency decrement across the stator was approximately 1 percentage point greater with the CD balde sections than with the DCA blade sections.

Gelder, Thomas F.; Schmidt, James F.; Suder, Kenneth L.; Hathaway, Michael D.

1987-01-01

15

Design and performance of controlled-diffusion stator compared with original double-circular-arc stator  

NASA Technical Reports Server (NTRS)

The capabilities of two stators, one with controlled-diffusion (CD) blade sections and one with double-circular-arc (DCA) blade sections, were compared. A CD stator was designed and tested that had the same chord length but half the blades of the DCA stator. The same fan rotor (tip speed, 429 m/sec; pressure ratio, 1.65) was used with each stator row. The design and analysis system is briefly described. The overall stage and rotor performances with each stator are compared, as are selected blade element data. The minimum overall efficiency decrement across the stator was approximately 1 percentage point greater with the CD blade sections than with the DCA blade sections.

Gelder, Thomas F.; Schmidt, James F.; Suder, Kenneth L.; Hathaway, Michael D.

1987-01-01

16

Rotor-Stator Interaction Performance Effects  

NASA Technical Reports Server (NTRS)

Decreased axial spacing between blade rows in an axial compressor stage is thought to increase stage performance because of an unsteady process that occurs in the downstream blade row and acts on the upstream blade row wakes. This process results in the "recovery" of part of the wake energy before all of this energy is irreversibly lost due to viscous diffusion. To study the wake-blade interaction mechanism, researchers at the NASA Lewis Research Center acquired two-component Laser Fringe Anemometer measurements of the rotor wake in the single-stage transonic compressor at two stage loading levels. The detailed measurements were acquired for one stator pitch in circumference at axial positions from the rotor trailing edge to 20 percent of the stator axial chord, at the exit of the stator passage, and downstream of the stator row including the stator wake. These data show that the changes in wake energy that occur inside the stator passage are not due to viscous dissipation alone, and thus the data provide evidence that "wake recovery" is occurring. A time-accurate, three-dimensional Navier Stokes simulation of the compressor stator was done at the corresponding stage loading levels. The measurements and simulations are being used in combination to show the effects of stator blade loading, quantify the effects of viscosity, and quantify the stage efficiency gain due to the wake recovery process. The accuracy of simple models of the wake recovery process is being evaluated in an effort to include the effects of wake recovery in the NASA-developed Average Passage code for multistage turbomachinery simulations.

VanZante, Dale E.

1997-01-01

17

Diagnostico de Prenez en Ganado Vacuno.  

E-print Network

$ vacas d para colamrse de palpau6n &b&a perrnitir,que el animal se pare a.a&&ksd3-- -ww,.~M..~m - d- TABLA I. COSTO DE PRODUCCION POR LIBRA DE PESO VIVO-EL COSTO DE OPERACION ES DE $95.00 POR VACA Peso al destete (libras) 550 500 450 400 350... palpar. Un;i mano puede agarrar la cola de la vaca como punto tle sosten. La otra del~e estar lien lubricada y con 10s dedos juntos en forma de cuiia. Se debe introducir la mano a travks del ano y en el recto con una presi6n constante y rripida...

Sorensen, A. M. Jr.; Beverly, J. R.; Arias, A. A.

1975-01-01

18

Evaluation of ceramics for stator applications: Gas turbine engines interim report. Stator fabrication and evaluation  

NASA Technical Reports Server (NTRS)

The objective was to assess current ceramic materials, fabrication processes, reliability prediction, and stator durability when subjected to simulated automotive gas turbine engine operating conditions. Ceramic one-piece stators were fabricated of two materials, silicon nitride and silicon carbide, using two near-net-shape processes, slip casting and injection molding. Non-destructive evaluation tests were conducted on all stators identifying irregularities which could contribute to failures under durability testing. Development of the test rig and automatic control system for repeatably controlling air flow rate and temperature over a highly transient durability duty cycle is discussed. Durability results are presented for repeated thermal cycle testing of the ceramic one-piece stators. Two duty cycles were used, encompassing the temperature ranges of 704 to 1204 C (1300 to 2200 F) and 871 to 1371 C (1600 to 2500 F). Tests were conducted on 28 stators, accumulating 135,551 cycles in 2441 hours of hot testing. Cyclic durability for the ceramic one-piece stator was demonstrated to be in excess of 500 hours, accumulating over 28,850 thermal cycles. Ceramic interface forces were found to be the significant factor in limiting stator life rather than the scatter in material strength properties or the variation in component defects encountered.

Arnon, N.; Trela, W.

1983-01-01

19

Benefits of Swept and Leaned Stators for Fan Noise Reduction  

NASA Technical Reports Server (NTRS)

An advanced high bypass ratio fan model was tested in the NASA Lewis Research Center 9 x 15-Foot Low Speed Wind Tunnel. The primary focus of this test was to quantify the acoustic benefits and aerodynamic performance of sweep and lean in stator vane design. Three stator sets were used for this test series. A conventional radial stator was tested at two rotor-stator axial spacings. Additional stator sets incorporating sweep + lean, and sweep only were also tested. The hub axial location for the swept + lean, and sweep only stators corresponded to the location of the radial stator at the upstream rotor-stator spacing, while the tip axial location of these modified stators corresponded to the radial stator axial position at the downstream position. The acoustic results show significant reductions in both rotor-stator interaction noise and broadband noise beyond what could be achieved through increased axial spacing of the conventional, radial stator. Theoretical application of these results to acoustically quantify a fictitious 2-engine aircraft and flight path suggested that about 3 Effective Perceived Noise (EPN) dB could be achieved through incorporation of these modified stators. This reduction would represent a significant portion of the 6 EPNdB noise goal of the current NASA Advanced Subsonic Technology (AST) initiative relative to that of 1992 technology levels. A secondary result of this fan test was to demonstrate the ability of an acoustic barrier wall to block aft-radiated fan noise in the wind tunnel, thus revealing the acoustic structure of the residual inlet-radiated noise. This technology should prove valuable toward better understanding inlet liner design, or wherever it is desirable to eliminate aft-radiated noise from the fan acoustic signature.

Woodward, Richard P.; Elliott, David M.; Hughes, Christopher E.; Berton, Jeffrey J.

1998-01-01

20

High-speed compulsator stator thermal management  

Microsoft Academic Search

The compulsator stator armature winding includes multiple conductor layers. Each conductor layer is made of insulation wraps and transposed aluminum litz wire bundles with epoxy potting compound between the wires and the wire bundles. For a typical pulse-duty application, based on a room-temperature electrical loss calculation, the temperature rise in the aluminum winding is approximately 30°C per shot. Adequate active

Hsing P. Liu; Jonathan J. Hahne

2003-01-01

21

Small axial turbine stator technology program  

NASA Technical Reports Server (NTRS)

An experimental investigation was conducted to determine the effects of surface finish, fillet radius, inlet boundary layer thickness, and free-stream inlet turbulence level on the aerodynamic performance of a small axial flow turbine stator. The principal objective of this program was to help understand why large turbine efficiency is not maintained when a large turbine is scaled to a smaller size. The stator used in this program as a one-sixth scale of a 762 mm (30 in.) diameter stator design with 50 vanes having a vane height of 17 mm (0.666 in.) and an aspect ratio of 1.77. A comprehensive overall test matrix was used to provide a complete engineering understanding of the effects of each variable over the full range of all the other variables. The range of each variable investigated was as follows: surface finish 0.1 micro (4 micro in.) to 2.4 micro (95 micro in.); boundary layer thickness 2 to 25 percent of channel height at each wall; fillet radius 0 mm (0 in.) to 1.0 mm (.040 in.) and turbulence 2 to 12 percent.

Brockett, W.; Kozak, A.

1982-01-01

22

Overview of Stator-Permanent Magnet Brushless Machines  

Microsoft Academic Search

Permanent magnet (PM) brushless machines having magnets and windings in stator (the so-called stator-PM machines) have attracted more and more attention in the past decade due to its definite advantages of robust structure, high power density, high efficiency, etc. In this paper, an overview of the stator-PM ma- chine is presented, with particular emphasis on concepts, opera- tion principles, machine

Ming Cheng; Wei Hua; Jianzhong Zhang; Wenxiang Zhao

2011-01-01

23

Sequential cooling insert for turbine stator vane  

DOEpatents

A sequential impingement cooling insert for a turbine stator vane that forms a double impingement for the pressure and suction sides of the vane or a triple impingement. The insert is formed from a sheet metal formed in a zigzag shape that forms a series of alternating impingement cooling channels with return air channels, where pressure side and suction side impingement cooling plates are secured over the zigzag shaped main piece. Another embodiment includes the insert formed from one or two blocks of material in which the impingement channels and return air channels are machined into each block.

Jones, Russel B; Krueger, Judson J; Plank, William L

2014-11-04

24

Generator stator core vent duct spacer posts  

DOEpatents

Generator stator cores are constructed by stacking many layers of magnetic laminations. Ventilation ducts may be inserted between these layers by inserting spacers into the core stack. The ventilation ducts allow for the passage of cooling gas through the core during operation. The spacers or spacer posts are positioned between groups of the magnetic laminations to define the ventilation ducts. The spacer posts are secured with longitudinal axes thereof substantially parallel to the core axis. With this structure, core tightness can be assured while maximizing ventilation duct cross section for gas flow and minimizing magnetic loss in the spacers.

Griffith, John Wesley (Schenectady, NY); Tong, Wei (Clifton Park, NY)

2003-06-24

25

Sequential cooling insert for turbine stator vane  

DOEpatents

A sequential impingement cooling insert for a turbine stator vane that forms a double impingement for the pressure and suction sides of the vane or a triple impingement. The insert is formed from a sheet metal formed in a zigzag shape that forms a series of alternating impingement cooling channels with return air channels, where pressure side and suction side impingement cooling plates are secured over the zigzag shaped main piece. Another embodiment includes the insert formed from one or two blocks of material in which the impingement channels and return air channels are machined into each block.

Jones, Russell B; Krueger, Judson J; Plank, William L

2014-04-01

26

Monitoring Of Generator Stator Core Lamination Repairs Using Thermographic Techniques  

NASA Astrophysics Data System (ADS)

Thermographic techniques have for years been used to locate minor interlaminar faults in the stator cores of steam turbine-driven generators. The technique has been largely employed in a quality control or routine maintenance function. However similar thermo-graphic techniques can be used to detect interlaminar faults and monitor repairs of an extensively damaged stator core of a large hydroelectric generator.

Stevens, D. C.

1983-03-01

27

Numerical modelling of a supersonic axial turbine stator  

NASA Astrophysics Data System (ADS)

In order to improve the turbocharging process, a supersonic axial turbine stator was modelled numerically with a pulsatile inlet mass flow. The main objectives of the study were to find out how pulsation affects the flow field and the performance of the stator. At the beginning of the study, a supersonic turbine stator was modelled using three different techniques: quasi-steady, time-accurate with constant boundary conditions and time-accurate with a pulsatile inlet mass flow. The time-averaged and quasi-steady flow fields and performance were compared, and the flow field and stator performance with a pulsatile inlet mass flow was studied in detail at different time-steps. A hysteresis-like behaviour was captured when the total-to-static pressure ratio and efficiency were plotted as a function of the inlet mass flow over one pulse period. The total-to-static pressure ratio and efficiency followed the sinusoidal shape of the inlet flow as a function of time. It was also concluded that the stator efficiency decreases downstream from the stator trailing edge and the amplitude of the pulsating mass flow is decreased at the stator throat.

Grönman, Aki; Turunen-Saaresti, Teemu; Jaatinen, Ahti; Backman, Jari

2010-06-01

28

Turbine rotor/stator flowfield analysis  

SciTech Connect

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: the first state of the United Technologies Research Center large scale rotating rig and the first state of the Space Shuttle main engine (SSME) high pressure fuel turbopump. Time-averaged blade midspan pressure and heat transfer profiles are calculated using the following different surface boundary conditions: adiabatic wall, prescribed wall temperature, and prescribed heat flux. Numerical solutions for the large scale rotating rig are compared with experimental data. Unsteady pressure envelopes are also presented for each geometry. In addition, instantaneous contours are plotted for the SSME configuration.

Griffin, L.

1989-03-01

29

Design considerations for a stator side voltage regulated permanent magnet AC generator  

Microsoft Academic Search

The application of permanent magnet generators in variable-speed applications is made difficult by the lack of a direct field control and the variation of the stator voltage with shaft speed and also with load. This paper presents the use of reactive power injection into the stator as a means of regulating the stator voltage. Design-oriented analysis of the machine stator

Neal Clements; Giri Venkataramanan; T. M. Jahns

2009-01-01

30

PI and fuzzy estimators for tuning the stator resistance in direct torque control of induction machines  

Microsoft Academic Search

Direct torque control (DTC) of induction machines uses the stator resistance of the machine for estimation of the stator flux. Variations of stator resistance due to changes in temperature or frequency make the operation of DTC difficult at low speeds. A method for the estimation of changes in stator resistance during the operation of the machine is presented. The estimation

Sayeed Mir; Malik E. Elbuluk; Donald S. Zinger

1998-01-01

31

Predicting the localized flux distribution in three phase induction motor between different stator slot size  

Microsoft Academic Search

A three phase induction motor differences of stator slot size is investigated in terms of its localized flux distribution. The search coil induced voltage method is used to analyze the flux distribution in the stator core. For both stator models, the maximum flux density is found near the tooth tip and minimum towards the outer region of the stator core.

S. Nor Shafiqin; N. H. Halim; I. Daut; Y. Yanawati; M. Asri; M. Dina; N. Gomesh; I. Pungut; M. Abdullah; M. N. Syatirah

2011-01-01

32

Stator current demodulation for induction machine rotor faults diagnosis  

E-print Network

Stator current demodulation for induction machine rotor faults diagnosis El Houssin El Bouchikhi faults detection and diagnosis. The demodulation techniques can be classified into mono faults detection. Keywords--Induction machine; eccentricity faults; broken ro- tor bars; diagnosis

Boyer, Edmond

33

The vortex interaction in a propeller/stator flow field  

NASA Technical Reports Server (NTRS)

The vortex interaction encounered in the flow field of a propeller and a stator has been investigated using smoke flow visualization. A stator at angle of attack was used to generate a line vortex which interacted with the helical vortex filaments generated by a propeller. Changes in the relative vortex strengths and vortex rotational directions yielded several distinct vortex structures. Axial flow in the vortex cores is determined to influence the development of the vortex interaction.

Johnston, R. T.; Sullivan, J. P.

1991-01-01

34

Impulsive Injection for Compressor Stator Separation Control  

NASA Technical Reports Server (NTRS)

Flow control using impulsive injection from the suction surface of a stator vane has been applied in a low speed axial compressor. Impulsive injection is shown to significantly reduce separation relative to steady injection for vanes that were induced to separate by an increase in vane stagger angle of 4 degrees. Injected flow was applied to the airfoil suction surface using spanwise slots pitched in the streamwise direction. Injection was limited to the near-hub region, from 10 to 36 percent of span, to affect the dominant loss due to hub leakage flow. Actuation was provided externally using high-speed solenoid valves closely coupled to the vane tip. Variations in injected mass, frequency, and duty cycle are explored. The local corrected total pressure loss across the vane at the lower span region was reduced by over 20 percent. Additionally, low momentum fluid migrating from the hub region toward the tip was effectively suppressed resulting in an overall benefit which reduced corrected area averaged loss through the passage by 4 percent. The injection mass fraction used for impulsive actuation was typically less than 0.1 percent of the compressor through flow.

Culley, Dennis E.; Braunscheidel, Edward P.; Bright, Michelle M.

2005-01-01

35

Effects of long-chord acoustically treated stator vanes on fan noise. 1: Effect of long chord (taped stator)  

NASA Technical Reports Server (NTRS)

A set of long-chord stator vanes was designed to replace the vanes in an existing fan stage. The long vanes consisted of a turning section and axial extension pieces, both of which incorporated acoustic damping material. The acoustic damping material was made inactive for these tests by covering with metal tape, and the stator vanes were tested in three length configurations. Compared to the values for the original stage, broadband noise was reduced in the middle to high frequencies with the long stator vanes, but a broadband noise increase was observed at the low frequencies. No change was observed in the blade passage tone, but some aft end reduction in the overtones was observed.

Dittmar, J. H.; Scott, J. N.; Leonard, B. R.; Stakolich, E. G.

1975-01-01

36

Examination about the stator structure of the brushless DC motor manufactured in the soft magnetic composite  

Microsoft Academic Search

In recent years, there is the soft magnetic composite (SMC) as a material replaced with the magnetic steel sheet which is the conventional stator material. There is the feature that manufacture with 3D stator structure is possible for SMC. We propose the stator structure which uses the feature of this SMC. It is the structure which cannot be conventionally manufactured

Yoshiki Okada; Hideo Dohmeki

2009-01-01

37

Electromagnetic pump stator frame having power crossover struts  

DOEpatents

A stator frame for an electromagnetic pump includes a casing joined to a hub by a plurality of circumferentially spaced apart struts. At least one electrically insulated power crossover lead extends through the hub, through a crossover one of the struts, and through the casing for carrying electrical current therethrough.

Fanning, Alan W. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

1995-01-01

38

Analysis of optimal stator concentric winding patterns design  

Microsoft Academic Search

Most small induction motors in current use employ concentric windings which have equal numbers of turns per coil. An optimal choice of turns can achieve better distribution of MMF in the gap while keeping the turns in each slot essentially the same. In this paper, the air gap magnetic motive force (MMF) harmonics of electrical machine created by the stator

Wen Ouyang; A. El-Antably; Surong Huang; T.A. Lipo

2005-01-01

39

Analytical calculation model for stator winding faults in synchronous machines  

Microsoft Academic Search

The calculation of currents and torques after inner faults in the stator of synchronous machines requires accurate models considering the inner asymmetry of the winding. The paper introduces a mathematical network model of a synchronous machine with arbitrary short circuited windings, which is generally open for the consideration of nonlinear iron. The system of equations is derived using an example

Jens Rosendahl; Hendrik Steins

2010-01-01

40

Numerical field calculation of stator winding faults in synchronous machines  

Microsoft Academic Search

Purpose – The purpose of this paper is to describe a systematic investigation of the currents, torques and other electromagnetic quantities in a machine after different short circuits by the means of coupled numerical field and network calculation. The behaviour of a synchronous machine after a stator-winding fault still is a little known issue. Nevertheless, the occurrence of winding faults

Jens Rosendahl; Stefan Kulig

2009-01-01

41

Numerical modeling of a OK rotor-stator mixing device  

Microsoft Academic Search

The flow field induced in an Outokumpu TankCell and by a OK rotor-stator mixing device in a process size flotation cell was simulated by cfd using two main grid types. The effects of different grid types were investigated with structured and unstructured grids. The geometry used was axisymmetric and a sector of 60 degrees of the tank with periodic boundaries

J. Tiitinen

2003-01-01

42

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

43

Low power stator core fault testing using EL CID  

Microsoft Academic Search

Generator stators are made from thin laminations with interlaminar insulation, defects in which permit damaging currents to flow. Traditional test methods require a substantial supply to excite the core at rated magnetic flux, temperature rises due to faults being detected by various means. The test is performed with the rotor removed and requires significant time and labour. The alternative low

D. B. Paley

1998-01-01

44

Aeropropulsion Technology (APT). Task 23 - Stator Seal Cavity Flow Investigation  

NASA Technical Reports Server (NTRS)

The focus of NASA Contract NAS3-25950 Task 23 was to numerically investigate the flow through an axial compressor inner-banded stator seal cavity. The Allison/NASA developed ADPAC code was used to obtain all flow predictions. Flow through a labyrinth stator seal cavity of a high-speed compressor was modeled by coupling the cavity flow path and the main flow path of the compressor. A grid resolution study was performed to guarantee adequate grid spacing was used. Both unsteady rotor-stator-rotor interactions and steady-state isolated blade calculations were performed with and without the seal cavity present. A parameterized seal cavity study of the high-speed stator seal cavity collected a series of solutions for geometric variations. The parameter list included seal tooth gap, cavity depth, wheel speed, radial mismatch of hub flowpath, axial trench gap, hub corner treatments, and land edge treatments. Solution data presented includes radial and pitchwise distributions of flow variables and particle traces describing the flow character.

Heidegger, N. J.; Hall, E. J.; Delaney, R. A.

1996-01-01

45

Slanted and saw-toothed stator poles for improved performance of doubly salient permanent magnet motor  

NASA Astrophysics Data System (ADS)

This paper presents the results of extensive finite element analyses conducted on doubly salient permanent magnet motor (DSPM) for improving the torque characteristics by novel methods; namely (i) slanted stator pole and (ii) saw-toothed stator pole. In the first method, stator poles are given a slant at the pole face; the slant in a direction opposite to the rotation of the motor has resulted in 7.33% and 71.45% increase in the average and maximum torques, respectively, when compared with the motor with original stator poles. With appropriate saw-tooth shaped stator poles, various permanent magnet torque and static torque profiles can be achieved.

Babu, A. R. C. Sekhar; Rajagopal, K. R.

2005-05-01

46

Method Of Wire Insertion For Electric Machine Stators  

DOEpatents

A method of inserting coils in slots of a stator is provided. The method includes interleaving a first set of first phase windings and a first set of second phase windings on an insertion tool. The method also includes activating the insertion tool to radially insert the first set of first phase windings and the first set of second phase windings in the slots of the stator. In one embodiment, interleaving the first set of first phase windings and the first set of second phase windings on the insertion tool includes forming the first set of first phase windings in first phase openings defined in the insertion tool, and forming the first set of second phase windings in second phase openings defined in the insertion tool.

Brown, David L (Westfield, IN); Stabel, Gerald R (Swartz Creek, MI); Lawrence, Robert Anthony (Kokomo, IN)

2005-02-08

47

Stator Loading Measurements Behind a Fan With Trailing Edge Blowing  

NASA Technical Reports Server (NTRS)

The problem of aircraft noise pollution around airports has become increasingly important as those areas have become more densely populated. Currently, the removal of older noisier aircraft from operation is reducing noise levels around airports; however, with air traffic projected to increase by about 5% over the next decade the number of commercial aircraft operating in the world is expected to be about 17,700 by the year 2007. To keep noise levels around airports from increasing as a result of traffic increases, it is important to investigate new methods of noise reduction. The objective of this work is to provide a better understanding of the effects that trailing edge blowing has on stator unsteady loading. This is done by presenting flowfield and stator loading data from experiments conducted with and without trailing edge blowing.

Waitz, Ian A.

2000-01-01

48

Low-cost stator material for M734 alternators  

Microsoft Academic Search

Silicon steels costing only $0.50 per pound were studied as substitutes for Permalloy used to fabricate two-piece stators for air driven alternators used to power the fuze electronics and to furnish a mechanical arming signature. Nickel-coated M-36 silicon electrical steel is a suitable substitute for the Permalloy which costs $6.00 per pound. However, differences in stamping and drawing properties from

J. E. Fine

1983-01-01

49

Measurements of a stator-induced circumferentially varying flow  

Microsoft Academic Search

The flow physics associated with the generation of both axisymmetric and non-axisymmetric swirl by various deflection patterns\\u000a of a stator array was investigated experimentally through surface pressure and Stereoscopic Particle Image Velocimetry measurements.\\u000a A three-dimensional rendering technique was developed to reconstruct the flow field around the model and in its wake. The\\u000a three-dimensional fluid volume was reconstructed from multiple two-dimensional

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

2011-01-01

50

Experience with 100% stator ground fault protection schemes  

Microsoft Academic Search

This paper discusses the experiences of several users with the application of three different 100% stator ground fault protection schemes. Two third-harmonic methods and a low frequency-injection method are included. This paper explains situations in which third-harmonic schemes work, and also the limitations of these schemes, which are not well understood by many relay engineers. It also discusses the use

Charles J. Mozina

2008-01-01

51

Experience with 100% stator ground fault protection schemes  

Microsoft Academic Search

This paper discusses the experiences of several users with the application of three different 100% stator ground fault protection schemes. Two third-harmonic methods and a low frequency-injection method are included. This paper explains situations in which third-harmonic schemes work, and also the limitations of these schemes, which are not well understood by many relay engineers. It also discusses the use

Charles J. Mozina

2009-01-01

52

Reduction of Wake-Stator Interaction Noise Using Passive Porosity  

NASA Technical Reports Server (NTRS)

The present study was conducted to assess the potential of Passive Porosity Technology as a mechanism to reduce interaction noise in turbomachinery by reducing the fluctuating forces acting on the vane surfaces. To do so, a typical fan stator airfoil was subjected to the effects of a transversely moving wake; time histories of the primitive aerodynamic variables, obtained from Computational Fluid Dynamics (CFD) solutions, were then input into an acoustic prediction code. This procedure was performed on the solid airfoil to obtain a baseline, and on a series of porous configurations in order to isolate those that yield maximum noise reductions without compromising the aerodynamic performance of the stator. It was found that communication between regions of high pressure differential - made possible by the use of passive porosity - is necessary to significantly alter the noise radiation pattern of the stator airfoil. In general, noise reductions were obtained for those configurations incorporating passive porosity in the region between x/c is approximately 0.15 on the suction side of the airfoil and x/c is approximately 0.20 on the pressure side. Reductions in overall radiated noise of approximately 1.0 dB were obtained. The noise benefit increased to about 2.5 dB when the effects of loading noise alone were considered.

Tinetti, Ana F.; Kelly, Jeffrey J.; Thomas, Russell H.; Bauer, Steven X. S.

2002-01-01

53

Design and experimental results for a turbine with jet flap stator and jet flap  

NASA Technical Reports Server (NTRS)

The overall performance and detailed stator performance of a negative hub reaction turbine design featuring a moderately low solidity jet flap stator and a jet flap rotor were determined. Testing was conducted over a range of turbine expansion ratios at design speed. At each expansion ratio, the stator jet flow and rotor jet flow ranged up to about 7 and 8 percent, respectively, of the turbine inlet flow. The performance of the jet flap stator/jet flap rotor turbine was compared with that of a turbine which used the same jet flap rotor and a conventional, high solidity plan stator. The effect on performance of increased axial spacing between the jet stator and rotor was also investigated.

Bettner, J. L.; Blessing, J. O.

1973-01-01

54

A planar variable reluctance magnetic micromotor with fully integrated stator and wrapped coils  

Microsoft Academic Search

A fully functional electrical excited planar variable reluctance magnetic micromotor has been demonstrated on a silicon wafer. The motor uses a micromachined nickel-iron rotor and a fully integrated stator, in which a toroidal-meander-type integrated inductive component is used for flux generation. To reduce the magnetic reluctance in the stator, a modified stator geometry that removes the yoke used in a

Chong H. Ahn; Yong J. Kim; Mark G. Allen

1993-01-01

55

Optimal design of a double-stator permanent magnet brushless machine with series magnetic circuit  

Microsoft Academic Search

This paper presents the optimal design of an 18-slot 8-pole double-stator permanent magnet brushless (DS-PMBL) machine. The key is to optimize the split ratio, namely the ratio of the inner-stator outside diameter to the outer-stator outside diameter, to achieve the maximum torque density under the same copper loss. Both the finite element analysis and experimental results are given to verify

Yubin Wang; Ming Cheng; Ying Fan; Xikai Sun; Wei Hua; K. T. Chau

2010-01-01

56

Turbine for ordnance turbojet engine. 2: Cold-air performance with opened stator  

NASA Technical Reports Server (NTRS)

A single-stage axial-flow turbine was investigated to determine the effect of increased stator throat area on the performance level of a turbojet engine turbine. The stator blades were bent to increase the throat area in order to move the compressor operating point in the engine farther away from surge. Results are compared with those obtained with the as-cast stator setting.

Kofskey, M. G.; Nusbaum, W. J.; Haas, J. E.

1974-01-01

57

On the design of dual-stator windings for safe VSI fed AC machine drives  

Microsoft Academic Search

The major drawback of usual dual-stator AC machines supplied by a voltage source inverter (VSI) is the occurrence of large circulating harmonic currents, causing extra losses. This paper deals with the design of dual-stator winding AC machines for safe operation with VSI. A new reference frame model of a dual-stator induction machine (DSIM), including mutual leakage coupling, is proposed. The

D. Hadiouche; H. Razik; A. Rezzoug

2001-01-01

58

Interturn stator winding fault diagnosis in three-phase induction motors, by Park's vector approach  

Microsoft Academic Search

The subject of on-line detection and location of inter-turn short circuits in the stator windings of three-phase induction motors is discussed, and a noninvasive approach, based on the computer-aided monitoring of the stator current Park's vector, is introduced. Experimental results, obtained by using a special fault producing test rig, demonstrate the effectiveness of the proposed technique, for detecting inter-turn stator

A. J. Marques Cardoso; S. M. A. Cruz; D. S. B. Fonseca

1999-01-01

59

A block-based algorithm for the solution of compressible flows in rotor-stator combinations  

NASA Technical Reports Server (NTRS)

A block-based solution algorithm is developed for the solution of compressible flows in rotor-stator combinations. The method allows concurrent solution of multiple solution blocks in parallel machines. It also allows a time averaged interaction at the stator-rotor interfaces. Numerical results are presented to illustrate the performance of the algorithm. The effect of the interaction between the stator and rotor is evaluated.

Akay, H. U.; Ecer, A.; Beskok, A.

1990-01-01

60

Luis Angel Salas Fonseca (1915-1999): maestro del diagnostico agricola  

Technology Transfer Automated Retrieval System (TEKTRAN)

The late Luis Angel Salas Fonseca, from the University of Costa Rica, was a world renowned researcher in agricultural entomology, plant-feeding nematodes, and plant-feeding mites. This paper provides a summary of his career and his important contributions to the study of pestiferous insects and mit...

61

Analytic investigation of effect of end-wall contouring on stator performance  

NASA Technical Reports Server (NTRS)

Calculations show improved stator performance when the tip end wall was contoured so that the inlet area was greater than the exit area. Comparisons are made with previously published experimental data. The results of a parametric analysis of the effect contour geometry on the efficiency of a highly loaded axial stator are given. The maximum stator efficiency gain is about 0.8 percentage point, and this represents a 22 percent reduction in stator losses. The degree to which endwall contouring reduces the forces driving secondary flows was also examined. The driving forces for both cross channel and radial secondary flow were reduced.

Boyle, R. J.; Rholik, H. E.; Goldman, L. J.

1981-01-01

62

Analytical and experimental investigation of stator endwall countouring in a small axial-flow turbine  

NASA Technical Reports Server (NTRS)

An experimental and analytical investigation was conducted to determine the effect of stator endwall contouring on turbine stage performance. In this investigation three stator configurations were evaluated using a common rotor. The three stator configurations were a cylindrical endwall design and two contoured endwall designs, one having a S-shaped outer wall profile and the other having a conical-shaped outer wall profile. Experimental data were obtained over a range of equivalent speeds, total pressure ratios, and rotor tip clearances for each stator-rotor combination. Detailed analytical loss assessments were conducted to aid in the determination of the contouring effect on turbine performance.

Haas, J. E.; Boyle, R. J.

1984-01-01

63

Stator flux estimation from inverter switching states for the field oriented control of induction generators  

SciTech Connect

A study of stator flux estimation from inverter switching states for the Stator flux oriented Control (SFOC) of induction generators for power generation application is presented. After reviewed the main drawbacks of the Rotor Flux Oriented Control (RFOC) system for the above mentioned application, stator voltage reconstruction from inverter switching states and methods of stator flux estimation and implementation issues are described. SFOC algorithm is implemented with the proposed estimation technique using a digital signal processor. Tests are conducted on a 200 hp induction generator and the dynamic and steady state performance of the generator control system are presented.

John, G.; Erdman, W.; Hudson, R.; Fan, C.; Mahajan, S. [Kenetech Windpower, Livermore, CA (United States)

1995-12-31

64

Low-cost stator material for M734 alternators  

NASA Astrophysics Data System (ADS)

Silicon steels costing only $0.50 per pound were studied as substitutes for Permalloy used to fabricate two-piece stators for air driven alternators used to power the fuze electronics and to furnish a mechanical arming signature. Nickel-coated M-36 silicon electrical steel is a suitable substitute for the Permalloy which costs $6.00 per pound. However, differences in stamping and drawing properties from those of Permalloy affect the end-plate and housing contact surface and the ability to draw the cup that contains the bearing. Production dies must be developed that allow for the stamping and drawing properties of the electrical steel.

Fine, J. E.

1983-03-01

65

Cold-air performance of compressor-drive turbine of Department of Energy upgraded automobile gas turbine engine. 1: Volute-manifold and stator performance  

NASA Technical Reports Server (NTRS)

The aerodynamic performance of the inlet manifold and stator assembly of the compressor drive turbine was experimentally determined with cold air as the working fluid. The investigation included measurements of mass flow and stator-exit fluid torque as well as radial surveys of total pressure and flow angle at the stator inlet and annulus surveys of total pressure and flow angle at the stator exit. The stator-exit aftermixed flow conditions and overall stator efficiency were obtained and compared with their design values and the experimental results from three other stators. In addition, an analysis was made to determine the constituent aerodynamic losses that made up the stator kinetic energy loss.

Roelke, R. J.; Haas, J. E.

1981-01-01

66

Analytical and Experimental Study of Gearbox Mechanical Effect on the Induction Machine Stator Current Signature  

Microsoft Academic Search

The aim of this paper is the analytical and experimental study of a gearbox by using the stator current signature analysis in the driving induction machines. The mechanical study using the vibration signal analysis has been well studied before. Recently, some works have been performed to observe the vibration components of the mechanical part in the stator current spectrum for

Shahin Hedayati Kia; Humberto Henao; GÉrard-AndrÉ Capolino

2009-01-01

67

Transient analysis of cage induction machines under stator, rotor bar and end ring faults  

Microsoft Academic Search

An analysis method is developed for modeling of multi phase cage induction motors with asymmetry in the stator, arising due to an interturn fault resulting in a disconnection of one or more coils making up a portion of a stator phase winding and any distribution and number of rotor bar and end-ring failures. The approach, based on the winding functions,

Hamid A. Toliyat; T.A. Lipo

1995-01-01

68

Wind Turbine Bearing Failure Detection Using Generator Stator Current Homopolar Component  

E-print Network

Wind Turbine Bearing Failure Detection Using Generator Stator Current Homopolar Component Ensemble detection of the generator health degeneration, facilitating a proactive response, minimizing downtime on the homopolar component of the generator stator current and attempts to highlight the use of the Ensemble

Paris-Sud XI, Université de

69

Measurement of large AC electrical machine stator windings parameters at high frequency  

Microsoft Academic Search

To analyze the propagation of high frequency signals, such as partial discharge, dv\\/dt, di\\/dt of PWM inverters in electric machines, it is necessary to determine the stator windings parameters at high frequency. This paper describes an experimental method for measuring the stator windings parameters of AC large electrical machine at high frequency. The method is based on the theory of

Z. L. Xian; J. G. Jiang; L. H. He; D. H. Liu; H. X. Cao

2003-01-01

70

Simulation of a High Temperature Superconducting Synchronous Machine with Stator Core Saturation  

Microsoft Academic Search

Saturation effects in salient pole synchronous machines are generally modelled by assuming that the saturation effect is primarily limited to the field pole. However, a superconducting machine does not possess field pole saturation since it is free of iron. The stator, however, remains surrounded by an iron shell so that saturation of the stator core is possible. This paper addresses

T. A. Lipo

71

Rail stator augmentation magnetic flux compression linear generator used in electric guns  

Microsoft Academic Search

In order to find an applicable power supply used in electric guns, there have been two types of the magnetic flux compression linear generator (MFCLG) that use the solenoids as the stators. That is to say, a piston armature or a solenoid armature is used within the stator. Although they can amplify the current theoretically, they can only compress the

Duan Xiaojun; Liu Zhengguo; Pang Guohua; Wang Ying; Li Zhiyuan

2004-01-01

72

Effects of Turn to Turn Stator Winding Faults in Synchronous Generators - A Numerical Study  

Microsoft Academic Search

The effects of stator winding faults on the behaviour of a synchronous generator are of interest for predicting the severity of the occurring damage. The paper in hand describes the numerical transient field and net- work calculation for the sudden occurrence of stator wind- ing turn to turn short circuits within coil groups and be- tween different phases. For a

Meinolf Klocke; Jens Rosendahl

73

Evaluation of the Degradation of Generator Stator Ground Wall Insulation Under Multistresses Aging  

Microsoft Academic Search

The actual stator bars of an 18 kV\\/300 MW generator were used for accelerated multistress aging tests to investigate the degradation of ground insulation. An aging system with combined stresses including thermal, electrical, mechanical vibration, and thermomechanical factors was used to test the aging of stator bar specimens. The nondestructive parameters including partial discharge (PD) quantities and dissipation factor parameters

Zhidong Jia; Xiang Peng; Zhicheng Guan; Liming Wang; Bo Yue

2008-01-01

74

What Stator Current Processing Based Technique to Use for Induction Motor Rotor Faults Diagnosis?  

E-print Network

What Stator Current Processing Based Technique to Use for Induction Motor Rotor Faults Diagnosis fault detection. Index Terms--Induction motor, rotor fault diagnosis, stator current. I. INTRODUCTION in induction motors. Features of these techniques which are relevant to fault detection are presented

Paris-Sud XI, Université de

75

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

76

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

77

An Electrostatic Lower, Stator Axial Gap Wobble Motor: Design And Fabrication  

Microsoft Academic Search

The fabrication, initial modelling and first results of an electrostatic lower stator axial gap wobble motor are presented. The four mask fabrication process is based on polysilicon surface micromachining techniques. Three to twelve stator pole wobble motor designs have been realized with rotor radii of 50 and 100 micrometer. A theoretical model predicts torque generations in the nNm range at

Rob Legtenberg; Erwin Berenschot; Baar van John; Theo Lammerink; Miko Elwenspoek

1995-01-01

78

Control of a Novel Dual Stator Doubly Salient Aircraft Engine Starter-Generator  

Microsoft Academic Search

A novel dual stator doubly salient aircraft engine starter-generator system has been designed and built for an aircraft engine application. The system bases on a dual stator doubly salient electromagnetic machine, which was chosen for its simplicity, ruggedness, high speed capability, low torque ripple in motoring and low output voltage ripple in generating. This paper describes the motor control system

Weili Dai; Tongcai Xiu; Huizhen Wang; Yangguang Yan

2006-01-01

79

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

E-print Network

Models for Bearing Damage Detection in Induction Motors Using Stator Current Monitoring Martin Bl of rolling-element bearing faults on induction motor stator cur- rent. Bearing problems are one major cause for drive failures. Their detection is possible by vibration monitoring of charac- teristic bearing

Paris-Sud XI, Université de

80

Incompressible lifting-surface aerodynamics for a rotor-stator combination  

NASA Technical Reports Server (NTRS)

Current literature on the three dimensional flow through compressor cascades deals with a row of rotor blades in isolation. Since the distance between the rotor and stator is usually 10 to 20 percent of the blade chord, the aerodynamic interference between them has to be considered for a proper evaluation of the aerothermodynamic performance of the stage. A unified approach to the aerodynamics of the incompressible flow through a stage is presented that uses the lifting surface theory for a compressor cascade of arbitrary camber and thickness distribution. The effects of rotor stator interference are represented as a linear function of the rotor and stator flows separately. The loading distribution on the rotor and stator flows separately. The loading distribution on the rotor and stator blades and the interference factor are determined concurrently through a matrix iteration process.

Ramachandra, S. M.

1984-01-01

81

Rotary catalysis of the stator ring of F(1)-ATPase.  

PubMed

F(1)-ATPase is a rotary motor protein in which 3 catalytic ?-subunits in a stator ?(3)?(3) ring undergo unidirectional and cooperative conformational changes to rotate the rotor ?-subunit upon adenosine triphosphate hydrolysis. The prevailing view of the mechanism behind this rotary catalysis elevated the ?-subunit as a "dictator" completely controlling the chemical and conformational states of the 3 catalytic ?-subunits. However, our recent observations using high-speed atomic force microscopy clearly revealed that the 3 ?-subunits undergo cyclic conformational changes even in the absence of the rotor ?-subunit, thus dethroning it from its dictatorial position. Here, we introduce our results in detail and discuss the possible operating principle behind the F(1)-ATPase, along with structurally related hexameric ATPases, also mentioning the possibility of generating hybrid nanomotors. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012). PMID:22465022

Iino, Ryota; Noji, Hiroyuki

2012-10-01

82

Turbine stator vane segment having internal cooling circuits  

DOEpatents

A turbine stator vane includes outer and inner walls each having outer and inner chambers and a vane extending between the outer and inner walls. The vane includes first, second, third, fourth and fifth cavities for flowing a cooling medium. The cooling medium enters the outer chamber of the outer wall, flows through an impingement plate for impingement cooling of the outer band wall defining in part the hot gas path and through openings in the first, second and fourth cavities for flow radially inwardly, cooling the vane. The spent cooling medium flows into the inner wall and inner chamber for flow through an impingement plate radially outwardly to cool the inner wall. The spent cooling medium flows through the third cavity for egress from the turbine vane segment from the outer wall. The first, second or third cavities contain inserts having impingement openings for impingement cooling of the vane walls. The fifth cavity provides air cooling for the trailing edge.

Jones, Raymond Joseph (Oxford, MA); Burns, James Lee (Schenectady, NY); Bojappa, Parvangada Ganapathy (Simpsonville, SC); Jones, Schotsch Margaret (Greer, SC)

2003-01-01

83

Acoustic Benefits of Stator Sweep and Lean for a High Tip Speed Fan  

NASA Technical Reports Server (NTRS)

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 booster stage, giving the model a nominal bypass ratio of 5. The model also had a simulated engine pylon and nozzle bifurcation contained within the bypass duct. The fan was tested with three stator sets to evaluate acoustic benefits associated with a swept and leaned stator and with a swept integral vane/frame stator which incorporated some of the swept and leaned features as well as eliminated some of the downstream support structure. The baseline fan with the wide chord rotor and baseline stator approximated a current GEAE CF6 engine. A flyover effective perceived noise level (EPNL) code was used to generate relative EPNL values for the various configurations. Flyover effective perceived noise levels (EPNL) were computed from the model data to help project noise benefits. A tone removal study was also performed. The swept and leaned stator showed a 3 EPNdB reduction at lower fan speeds relative to the baseline stator; while the swept integral vane/frame stator showed lowest noise levels at intermediate fan speeds. Removal of the bypass blade passage frequency rotor tone (BPF) showed a 4 EPNdB reduction for the baseline and swept and leaned stators, and a 6 EPNdB reduction for the swept integral vane/ frame stator. Therefore, selective tone removal techniques such as active noise control and/or tuned liner could be particularly effective in reducing noise levels for certain fan speeds.

Woodward, Richard P.; Gazzaniga, John A.; Bartos, Linda J.; Hughes, Christopher E.

2002-01-01

84

Basic Study on Loss Reduction Effect by Stator-Teeth Slits in Turbine Generators  

NASA Astrophysics Data System (ADS)

In this study, we investigate the loss reduction effect by stator-teeth slits in turbine generators on the basis of electromagnetic field analysis and basic experiments. First, the loss reduction effect in the generator is estimated by the 3-D finite element method and the theoretical solution of eddy current loss. Next, an experiment using a simple model that simulates the stator-core ends of the turbine generator is carried out. It is clarified that the loss reduction effect by the slits depends on the frequency, flux density, and permeability of the stator teeth because the loss reduction effect weakens with the skin effect.

Yamazaki, Katsumi; Nishioka, Kazuyoshi; Nakahara, Akihito; Furukawa, Yoko; Takahashi, Kazuhiko; Yabumoto, Masao

85

Non-linear dynamic of rotor-stator system with non-linear bearing clearance  

E-print Network

The study deals with a rotor-stator contact inducing vibration in rotating machinery. A numerical rotor-stator system, including a non-linear bearing with Hertz contact and clearance is considered. To determine the non-linear responses of this system, non-linear dynamic equations can be integrated numerically. However, this procedure is both time consuming and costly to perform. The aim of this Note is to apply the Alternate Frequency/Time Method and the 'path following continuation' in order to obtain the non-linear responses to this problem. Then the orbits of rotor and stator responses at various speeds are investigated.

Jean-Jacques Sinou; Fabrice Thouverez

2008-01-19

86

Experimental investigation of steady and unsteady flow field downstream of an automotive torque converter turbine and inside the stator. Part 2: Unsteady pressure on the stator blade surface  

SciTech Connect

The stator flow field of an automotive torque converter is highly unsteady due to potential and viscous interactions with upstream and downstream rotors. The objective of this investigation is to understand the influence of potential and viscous interactions of the upstream rotor on the stator surface pressure field with a view toward improvement of the stator design. Five miniature fast-response pressure transducers were embedded on the stator blade. The measurements were conducted at three locations near the leading edge and two locations near the trailing edge at the midspan location. The upstream flow field was measured using a fast response five-hole probe and is described in Part 1 of this paper. The experimental data were processed in the frequency domain by spectrum analysis and in the temporal-spatial domain by the ensemble-averaging technique. The flow properties were resolved into mean, periodic, aperiodic, and unresolved components. The unsteady amplitudes agreed well with the pressure envelope predicted by panel methods. The aperiodic component was found to be significant due to the rotor-rotor and rotor-stator interactions observed in multistage, multispool environment.

Marathe, B.V.; Lakshminarayana, B. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Aerospace Engineering; Maddock, D.G. [General Motors Corp., Ypsilanti, MI (United States). GM Powertrain Group

1997-07-01

87

Control of LP turbine rotor blade underloading using stator blade compound lean at root  

NASA Astrophysics Data System (ADS)

Due to a large gradient of reaction, LP rotor blades remain underloaded at the root over some range of volumetric flow rates. An interesting design to control the flow through the root passage of the overloaded stator and underloaded moving blade row is compound lean at the root of stator blades. The paper describes results of numerical investigations from a 3D NS solver FlowER conducted for several configurations of stator blade compound lean. The computations are carried out for a wide range of volumetric flow rates, accounting for the nominal operating regime as well as low and high load. It is found that compound lean induces additional blade force, streamwise curvature and redistribution of flow parameters in the stage, including pressure and mass flow rate spanwise that can improve the flow conditions in both the stator and the rotor. The obtained efficiency improvements depend greatly on the flow regime, with the highest gains in the region of low load.

Lampart, Piotr

2000-06-01

88

Harmonic control of multiple-stator induction machines for voltage regulation  

E-print Network

Small, one to a few horsepower, three-phase induction machines with three sets of electrically-isolated, magnetically-coupled stator winding circuits are described. A voltage inverter is developed and used to drive one set ...

Holloway, Jack Wade, 1980-

2004-01-01

89

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

90

Measurements of power loss distribution in a typical stator core under PWM voltage excitation  

NASA Astrophysics Data System (ADS)

The pulse width modulated (PWM) inverter is widely used to feed small induction motors for variable speed and torque control. When a laminated stator core is energised in this way additional iron losses occur due to localised distorted flux. Flux density and power loss distribution under PWM and sinusoidal voltage excitations were measured in a typical induction motor stator core lamination at 1.3 T, 50 Hz by using a computer-aided magnetising system to set up flux distribution as would occur in a practical three-phase stator core. The iron loss increased 15-20% under PWM excitation. The loss increase under PWM excitation in the stator core laminations was 3% lower than in Epstein strips of the same electrical steel under the same conditions showing an effect of the magnetic circuit geometry.

Tutkun, N.; Moses, A. J.

2003-06-01

91

Investigation about Rotor-stator Interaction with an Adjustable Leaned Vane Blade  

NASA Astrophysics Data System (ADS)

This paper focuses on the noise reduction benefits of stator lean effect for rotor-stator interaction. The compressor with 3 blade lean angle of downstream stator was investigated by experimental and numerical study. The noise spectra of the acoustic measurement were obtained by the outside noise test. And the tone noise was extracted from the total noise sound pressure level (SPL). The unsteady loading of the stators' blade surface were also obtained. The pressure fluctuation amplitude was extracted from the numerical study, and the phase distribution of the wake presented the detail distribution of the wake phase. The numerical study shows that lean positive has less unsteady loading than negative, and lean positive case has the maximum phase lag.

Wu, Yadong; Tian, Jie; Ouyang, Hua; Du, Zhaohui; Liu, Haijian

2014-12-01

92

Strength design and reliability evaluation of a hybrid ceramic stator vane for industrial gas turbines  

Microsoft Academic Search

Employing ceramic materials for the critical components of industrial gas turbines is anticipated to improve the thermal efficiency of power plants. We developed a first-stage stator vane for a 1300 C class, 20-MW industrial gas turbine. This stator vane has a hybrid ceramic\\/metal structure, to increase the strength reliability of brittle ceramic parts, and to reduce the amount of cooling

K. Nakakado; T. Machida; H. Miyata; T. Hisamatsu; N. Mori; I. Yuri

1995-01-01

93

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.

Moses, A. J.; Rahmatizadeh, H.

1992-07-01

94

A low cost stator flux oriented voltage source variable speed drive  

Microsoft Academic Search

A new control strategy for variable-speed drives is presented. It is aimed at improving or even replacing existing volts-per-hertz (V \\/f) open-loop variable-speed drives. This strategy generates d-q voltage commands in the stator-flux-oriented reference frame by closing a torque loop and a flux loop. Stator flux and electromagnetic torque feedback signals are derived from DC voltage, DC current, and inverter

Y. Xue; X. Xu; T. G. Habetler; D. M. Divan

1990-01-01

95

SSME seal test program: Test results for smooth, hole-pattern and helically-grooved stators  

NASA Technical Reports Server (NTRS)

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 supports the following conclusions: (1) For small seals, the Hirs' friction-factor model is more restricted than had been thought; (2) For smooth seals, predictions of stiffness and damping improve markedly as the radical clearance is reduced; (3) Friction-factor data for hole-pattern-seal stators frequently deviates from the Hirs model; (4) Predictions of stiffness and damping coefficients for hole-pattern-stator seals is generally reasonable; (5) Tests for the hole-pattern stators at reduced clearances show no clear optimum for hole-pattern seals with respect to either hole-area ratio or hole depth to minimum clearance ratios; (6) Tests of these hole-pattern stators show no significant advantage in net damping over smooth seals; (7) Tests of helically-grooved seal stators in Halon show reasonable agreement between theory and prediction for leakage and direct stiffness but poor agreement for the net damping coefficient.

Childs, Dara W.

1987-01-01

96

A comparison of experimental and theoretical results for labyrinth gas seals with honeycomb stators. M.S. Thesis  

NASA Technical Reports Server (NTRS)

Experimental results for the rotordynamic stiffness and damping coefficients of a labyrinth -rotor honeycomb-stator seal are presented. The coefficients are compared to the coefficients of a labyrinth-rotor smooth-stator seal having the same geometry. The coefficients are compared to analytical results from a two-control-volume compressible flow model. The experimental results show that the honeycomb stator configuration is more stable than the smooth stator configuration at low rotor speeds. At high rotor speeds and low clearance, the smooth stator seal is more stable. The theoretical model predicts the cross-coupled stiffness of the honeycomb stator seal correctly within 25 percent of measured values. The model provides accurate predictions of direct damping for large clearance seals. Overall, the model does not perform as well for low clearance seals as for high clearance seals.

Hawkins, Lawrence Allen

1988-01-01

97

15 years of experience with 100% generator stator ground fault protection— What works, what doesn't and why  

Microsoft Academic Search

This paper discusses the application of three different 100% stator ground fault protection schemes. Two third-harmonic methods and a low frequency-injection method are discussed. Third-harmonic schemes have been widely applied on generators within the U.S. to provide stator ground fault protection over the entire stator winding. This paper discusses situations in which third-harmonic schemes will work and outlines the limitations

Charles J. Mozina

2009-01-01

98

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

99

Effects of Shrouded Stator Cavity Flows on Multistage Axial Compressor Aerodynamic Performance  

NASA Technical Reports Server (NTRS)

Experiments were performed on a low-speed multistage axial-flow compressor to assess the effects of shrouded stator cavity flows on aerodynamic performance. Five configurations, which involved changes in seal-tooth leakage rates and/or elimination of the shrouded stator cavities, were tested. Data collected enabled differences in overall individual stage and the third stage blade element performance parameters to be compared. The results show conclusively that seal-tooth leakage ran have a large impact on compressor aerodynamic performance while the presence of the shrouded stator cavities alone seemed to have little influence. Overall performance data revealed that for every 1% increase in the seal-tooth clearance to blade-height ratio the pressure rise dropped up to 3% while efficiency was reduced by 1 to 1.5 points. These observed efficiency penalty slopes are comparable to those commonly reported for rotor and cantilevered stator tip clearance variations. Therefore, it appears that in order to correctly predict overall performance it is equally important to account for the effects of seal-tooth leakage as it is to include the influence of tip clearance flows. Third stage blade element performance data suggested that the performance degradation observed when leakage was increased was brought about in two distinct ways. First, increasing seal-tooth leakage directly spoiled the near hub performance of the stator row in which leakage occurred. Second, the altered stator exit now conditions caused by increased leakage impaired the performance of the next downstream stage by decreasing the work input of the downstream rotor and increasing total pressure loss of the downstream stator. These trends caused downstream stages to progressively perform worse. Other measurements were acquired to determine spatial and temporal flow field variations within the up-and-downstream shrouded stator cavities. Flow within the cavities involved low momentum fluid traveling primarily in the circumferential direction at about 40% of the hub wheel speed. Measurements indicated that the flow within both cavities was much more complex than first envisioned. A vortical flow structure in the meridional plane, similar to a driven cavity, existed within the upstream cavity Furthermore, other spatial and temporal variations in Row properties existed. the most prominent being caused by the upstream potential influence of the downstream blade. This influence caused the fluid within cavities near the leading edges of either stator blades in space or rotor blades in time to be driven radially inward relative to fluid near blade mid-pitch. This influence also produced large unsteady velocity fluctuations in the downstream cavity because of the passing of the downstream rotor blade.

Wellborn, Steven R.; Okiishi, Theodore H.

1996-01-01

100

Rotor Wake/Stator Interaction Noise Prediction Code Technical Documentation and User's Manual  

NASA Technical Reports Server (NTRS)

This report documents the improvements and enhancements made by Pratt & Whitney to two NASA programs which together will calculate noise from a rotor wake/stator interaction. The code is a combination of subroutines from two NASA programs with many new features added by Pratt & Whitney. To do a calculation V072 first uses a semi-empirical wake prediction to calculate the rotor wake characteristics at the stator leading edge. Results from the wake model are then automatically input into a rotor wake/stator interaction analytical noise prediction routine which calculates inlet aft sound power levels for the blade-passage-frequency tones and their harmonics, along with the complex radial mode amplitudes. The code allows for a noise calculation to be performed for a compressor rotor wake/stator interaction, a fan wake/FEGV interaction, or a fan wake/core stator interaction. This report is split into two parts, the first part discusses the technical documentation of the program as improved by Pratt & Whitney. The second part is a user's manual which describes how input files are created and how the code is run.

Topol, David A.; Mathews, Douglas C.

2010-01-01

101

Effect of endwall cooling on secondary flows in turbine stator vanes  

NASA Technical Reports Server (NTRS)

The effect of endwall cooling on the secondary flow behavior and the aerodynamic performance of a core turbine stator vane was determined. The investigation was conducted in a cold-air, full-annular cascade, where three-dimensional effects were obtained. Two endwall cooling configurations were tested. In the first configuration, the cooling holes were oriented so that the coolant was injected in line with the inviscid streamline direction. In the second configuration, the coolant was injected at an angle of 15 deg to the inviscid streamline direction and oriented towards the vane pressure stator. In both cases the stator vanes were solid and uncooled so that the effect of endwall cooling was obtained directly. Total-pressure surveys were taken downstream of the stator vanes over a range of cooling flows at the design, mean-radius, critical velocity ratio of 0.778. Changes in the total-pressure contours downstream of the vanes were used to obtain the effect of endwall cooling on the secondary flows in the stator.

Goldman, L. J.; Mclallin, K. L.

1977-01-01

102

Double-stator electromagnetic pump having alignment ring and spine assembly  

DOEpatents

A support structure for clamping the inner coils and inner lamination rings of an inner stator column of an electromagnetic induction pump to prevent damaging vibration. A spine assembly, including a base plate, a center post and a plurality of ribs, serves as the structural frame for the inner stator. Stacked alignment rings provide structure to the lamination rings and locate them concentrically around the spine assembly central axis. The alignment rings are made of a material having a high thermal expansion coefficient to compensate for the lower expansion of the lamination rings and, overall, provide an approximate match to the expansion of the inner flow duct. The net result is that the radial clamping provided by the duct around the stator iron is maintained (approximately) over a range of temperatures and operating conditions. Axial clamping of the inner stator structure is achieved via tie rods which run through grooves in the ribs and engage the base plate at the bottom of the inner stator and engage a clamping plate at the top. Slender tie rods and a flexible clamping plate are used to provide compliance in the axial clamping system to accommodate differential thermal growth (axially) between the tie rods and lamination ring elements without losing clamping force.

Fanning, Alan Wayne (San Jose, CA); Olich, Eugene Ellsworth (Aptos, CA); Dahl, Leslie Roy (Livermore, CA); Patel, Mahadeo Ratilal (San Jose, CA)

1997-01-01

103

Double-stator electromagnetic pump having alignment ring and spine assembly  

DOEpatents

A support structure for clamping the inner coils and inner lamination rings of an inner stator column of an electromagnetic induction pump to prevent damaging vibration is disclosed. A spine assembly, including a base plate, a center post and a plurality of ribs, serves as the structural frame for the inner stator. Stacked alignment rings provide structure to the lamination rings and locate them concentrically around the spine assembly central axis. The alignment rings are made of a material having a high thermal expansion coefficient to compensate for the lower expansion of the lamination rings and, overall, provide an approximate match to the expansion of the inner flow duct. The net result is that the radial clamping provided by the duct around the stator iron is maintained (approximately) over a range of temperatures and operating conditions. Axial clamping of the inner stator structure is achieved via tie rods which run through grooves in the ribs and engage the base plate at the bottom of the inner stator and engage a clamping plate at the top. Slender tie rods and a flexible clamping plate are used to provide compliance in the axial clamping system to accommodate differential thermal growth (axially) between the tie rods and lamination ring elements without losing clamping force. 12 figs.

Fanning, A.W.; Olich, E.E.; Dahl, L.R.; Patel, M.R.

1997-06-24

104

Multi-blade Navier-Stokes simulations of rotor-stator interaction in a turbine stage  

NASA Technical Reports Server (NTRS)

Turbulent flow fields of multiblade rotor/stator configurations in a turbine stage for the high pressure fuel side turbopump of the space shuttle main engine are obtained using a computer program that can simulate flows in a stage with an unequal number of rotor and stator blades. The calculations are performed on a system of multiple patched and overlaid grids using the unsteady, thin-layer Navier-Stokes equations in two-dimension. Aerodynamic performance of two rotor/stator configurations are studied and compared in the form of pressure contours, Mach number contours, time averaged surface pressure, and unsteady pressure amplitude. Spatial and temporal accuracy of flow calculations along with computation cost are evaluated for the purpose of engineering design applications.

Lin, S. J.; Yang, R. J.

1989-01-01

105

Influence of stator slots on the development of noise-generating magnetic force waves  

NASA Astrophysics Data System (ADS)

The calculation of noise in electrical machines is important in the design of these machines. It is shown that the magnetic anisotropy of a laminated stator core caused by stator slots has a substantial effect on the force waves acting on the yoke. The force waves are described simply using a modulation function and the Fourier coefficients of the waves. The effects of the amplitude of the magnetic force waves are discussed, and the effectiveness of stator slot skewing is determined. It is shown that subharmonics can be generated by the slotting (affecting the harmonic number of the force waves), and that for specific harmonic numbers, a reversal in the direction of rotation of force waves takes place. The effectiveness of the method is substantiated by a practical example.

Wachta, B.

106

Predicting broadband noise from a stator vane of a gas turbine engine  

NASA Technical Reports Server (NTRS)

A computer-implemented model of fan section of a gas turbine engine accounts for the turbulence in the gas flow emanating from the rotor assembly and impinging upon an inlet to the stator vane cascade. The model allows for user-input variations in the sweep and/or lean angles for the stator vanes. The model determines the resulting acoustic response of the fan section as a function of the turbulence and the lean and/or sweep angles of the vanes. The model may be embodied in software that is rapidly executed in a computer. This way, an optimum arrangement in terms of fan noise reduction is quickly determined for the stator vane lean and sweep physical positioning in the fan section of a gas turbine engine.

Hanson, Donald B. (Inventor)

2002-01-01

107

A circulation system with low boiling point medium to replace water-cooling medium for turbine generator stator  

Microsoft Academic Search

In this article, an evaporative cooling circulation system for turbine generator stator winding was introduced. The design has taken into account of the characteristics of the whole liquid cooling approach for the large turbine generator, the requirements for the 50MW turbine generator evaporative cooling for the stator as well as the physical and chemical characteristics of the low boiling point

Fu De Ping; Guo Jian Hong; Li Zhen Guo; Xiong Bin; Dong Hai Hong; Gu Guo Biao

2010-01-01

108

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

109

Reduced Perceived Noise Low Tip Speed Fans as a Result of Abandoning Cutoff Stator Vane Numbers  

NASA Technical Reports Server (NTRS)

As fan tip speeds are reduced, broadband noise is becoming more important in the calculation of perceived noise. Past experience indicates that lower vane number stators with either constant chord or constant solidity may be a way to reduce broadband noise caused by the interaction of the rotor wake turbulence with the stators. A baseline fan and a low blade number fan were investigated to determine if a noise reduction was possible. The low vane number fan showed a 2 PndB and a 1.5 PNLT noise reduction. These reductions show that this is a viable technique for reducing the perceived noise of low tip speed fans.

Dittmar, James

1998-01-01

110

A bio-inspired piezoelectric motor with simple structured asymmetric stator  

NASA Astrophysics Data System (ADS)

A new type of micro rotary motor with a single piezoelectric stack actuator has been proposed, developed and tested. The conventional principle of elliptical motion is realized by a proposed mechanism which utilizes a Y-shaped stator and a ring rotor, and the biomimetic gait of an inchworm is achieved by integrating one piezoelectric stack actuator into the stator. The performance of the motor is predicted on the basis of computational simulation. An experimental setup was built to validate the working principles and evaluate the performance. Preliminary results have verified the working principle. Differences between the measured and predicted performances of the motor are analyzed.

Zhou, Maoying; Ruan, Yuan; Liu, Weiting; Huang, Shuo; Fu, Xin

2014-04-01

111

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

112

A new stator-flux orientation strategy for flux-switching permanent magnet motor based on current-hysteresis control  

NASA Astrophysics Data System (ADS)

A stator-flux orientation strategy based on current hysteresis for the flux-switching permanent magnet (FSPM) motor is proposed, in which the stator-PM FSPM motor is considered as a conventional rotor-PM surface-mounted motor and an equivalent rotor-orientated dq-axes synchronous reference frame is built although there are actually no rotary magnetic motive force produced by the stator magnets in the FSPM motor. Based on the proposed model, a vector-control strategy with current hysteresis for the FSPM motor drive is investigated and implemented on a dSPACE-based platform, and both the simulated and experimental results validate the effectiveness. It should be emphasized that the proposed stator-flux orientation strategy can be applied to other stator-PM machines (including doubly salient and flux-reversal PM machines) and other control methods (including space-vector pulsed-width-modification and direct torque control).

Hua, Wei; Cheng, Ming; Lu, Wei; Jia, Hongyun

2009-04-01

113

A finite volume method and experimental study of a stator of a piezoelectric traveling wave rotary ultrasonic motor.  

PubMed

Piezoelectric traveling wave rotary ultrasonic motors are motors that generate torque by using the friction force between a piezoelectric composite ring (or disk-shaped stator) and a metallic ring (or disk-shaped rotor) when a traveling wave is excited in the stator. The motor speed is proportional to the amplitude of the traveling wave and, in order to obtain large amplitudes, the stator is excited at frequencies close to its resonance frequency. This paper presents a non-empirical partial differential equations model for the stator, which is discretized using the finite volume method. The fundamental frequency of the discretized model is computed and compared to the experimentally-measured operating frequency of the stator of Shinsei USR60 piezoelectric motor. PMID:24210273

Bolborici, V; Dawson, F P; Pugh, M C

2014-03-01

114

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

115

Investigation of end effect in permanent magnet brushless machines having magnets on the stator  

NASA Astrophysics Data System (ADS)

This paper investigates the influence of the end effect on the back-emf wave forms of flux-switching and doubly salient permanent magnet brushless machines, in which the magnets are located on the stator. Their electromagnetic performance is predicted from two-dimensional and three-dimensional finite element analyses and validated experimentally.

Zhu, Z. Q.; Pang, Y.; Hua, W.; Cheng, M.; Howe, D.

2006-04-01

116

Proposal of 3D-stator structure using soft magnetic composite for PM motor  

Microsoft Academic Search

This paper presents 3-dimentional motor core structure using soft magnetic composite. This motor aims to provide high motor efficiency compared with lamination core motor. Soft magnetic composite is applied to the stator to decrease iron loss. Using the magnetic field analysis by 3-dimentional finite element method, we confirmed the usefulness of proposal structure. Furthermore, we studied in the actual motor,

Yoshiki Okada; Hideo Dohmeki; Shinji Konushi

2010-01-01

117

Core losses in claw pole permanent magnet machines with soft magnetic composite stators  

Microsoft Academic Search

This paper presents the core loss calculation in soft magnetic composite (SMC) samples and a claw pole permanent magnet machine with SMC stator. By using finite-element analysis of the magnetic field, the total core loss is computed by separating the hysteresis (alternating and rotational, both purely circular and elliptical), eddy current, and anomalous losses in each element when the rotor

Youguang Guo; Jian Guo Zhu; Jin Jiang Zhong; Wei Wu

2003-01-01

118

Direct field orientation controller using the stator phase voltage third harmonic  

Microsoft Academic Search

This paper presents the development and implementation of a direct field orientation controller (DFOC) for induction machines based on determination of the spatial position of the air gap flux from the third harmonic component of the stator phase voltages. The control utilizes spatial saturation harmonic components rotating at synchronous frequency that are generated in the air gap flux when the

Liviu Kreindler; Julio C. Moreira; Antonio Testa; Thomas A. Lipo

1994-01-01

119

Blade-forced vibration effects in turbomachinery rotor-stator interaction  

E-print Network

This thesis presents the effects of blade-forced vibration in turbomachinery rotor-stator interaction. A quasi-three-dimensional multi-row analysis, based on an Euler/Navier-Stokes solver and a parallel computational algorithm, was used to simulate...

Collard, Joseph Eugene

2012-06-07

120

Using fiber-optic sensors to measure strain in motor stator end windings during operation  

Microsoft Academic Search

A novel technique incorporating fiber optic strain gages has been successfully used to measure the mechanical stresses on large motor stator winding end turns at different operating conditions. The testing was conducted both on high voltage, large horsepower and medium voltage, medium horsepower motors with form wound coils. The goals for this project were to: (1) accurately measure the mechanical

G. Gao; M. Steinhauser; R. Kavanaugh; W. Chen

1999-01-01

121

Synchronous Machine Operational Impeadances From Low Voltage Measurements at the Stator Terminals  

Microsoft Academic Search

Models of a synchronous machine for use in stability studies have been derived by measurements off-line at standstill. The method involves accurate determination of magnitude and phase of the impedance as seen at the stator terminals, for a range of frequency from 0.005 to 100 Hz. The data obtained pertains particularly to establishment of parameters for equivalent rotor circuits of

W. Watson; G. Manchur

1974-01-01

122

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

123

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

124

Comparison of Computational Aeroacoustics Prediction of Acoustic Transmission Through a 3D Stator With Experiment  

NASA Technical Reports Server (NTRS)

In this paper, numerical predictions of acoustic transmission through a 3D stator obtained using the NASA BASS code are compared with experimentally measured data. The influence of vane count and stagger as well as frequency and mode order on the transmission loss is investigated. The data-theory comparisons indicate that BASS can predict all the important trends observed in the experimental data.

Hixon, Ray; Envia, Edmane; Dahl, Milo; Sutliff, Daniel L.

2014-01-01

125

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

126

Epoxy Adhesives for Stator Magnet Assembly in Stirling Radioisotope Generators (SRG)  

NASA Technical Reports Server (NTRS)

As NASA seeks to fulfill its goals of exploration and understanding through missions planned to visit the moons of Saturn and beyond, a number of challenges arise from the idea of deep space flight. One of the first problems associated with deep space travel is electrical power production for systems on the spacecraft. Conventional methods such as solar power are not practical because efficiency decreases substantially as the craft moves away from the Sun. The criterion for power generation during deep space missions are very specific, the main points requiring high reliability, low mass, minimal vibration and a long lifespan. A Stirling generator, although fairly old in concept, is considered to be a potential solution for electrical power generation for deep space flight. A Stirling generator works on the same electromagnetic principles of a standard generator, using the linear motion of the alternator through the stationary stator which produces electric induction. The motion of the alternator, however, is produced by the heating and cooling dynamics of pressurized gases. Essentially heating one end and cooling another of a contained gas will cause a periodic expansion and compression of the gas from one side to the other, which a displacer translates into linear mechanical motion. NASA needs to confirm that the materials used in the generator will be able to withstand the rigors of space and the life expectancy of the mission. I am working on the verification of the epoxy adhesives used to bond magnets to the steel lamination stack to complete the stator; in terms of in-service performance and durability under various space environments. Understanding the proper curing conditions, high temperature properties, and degassing problems as well as production difficulties are crucial to the long term success of the generator. system and steel substrate used in the stator. To optimize the curing conditions of the epoxies, modulated differential scanning calorimetry analysis was done as a function of cure time and temperatures. Adhesion bond strength was tested at various temperatures with lap shear samples using Hiperco 50 substrate to ensure that the proper adhesive is being used. To try and solve the problem of bondline thickness, micro glass beads of 0.0017" in diameter were investigated to see if any other physical properties of the epoxy were affected. Efforts will be made to develop a standard, optimized, fabrication process/procedure of sub-scale magnet-stator assemblies for various adhesive performance evaluation studies under simulated generator conditions. Also, accelerated aging testing will be done in a pressurized canister with stator assembly samples for three years to verify if any degassing or thermal degradation of the epoxy occurs. The necessity of verifying the correct epoxy adhesive system for the stator magnet in the SRG is crucial because failure of the stator assembly would jeopardize the electrical system, and thereby the entire mission itself. My work involves specimen fabrications, testing, and data analyses of the epoxy adhesive system for the stator magnet in the SRG is crucial because failure of the stator assembly would jeopardize the electrical system, and thereby the entire mission itself.

Cater, George M.

2004-01-01

127

Simulation of unsteady flows through stator and rotor blades of a gas turbine using the Chimera method  

NASA Technical Reports Server (NTRS)

A two-dimensional model to solve compressible Navier-Stokes equations for the flow through stator and rotor blades of a turbine is developed. The flow domains for the stator and rotor blades are coupled by the Chimera method that makes grid generation easy and enhances accuracy because the area of the grid that have high turning of grid lines or high skewness can be eliminated from the computational domain after the grids are generated. The results of flow computations show various important features of unsteady flows including the acoustic waves interacting with boundary layers, Karman vortex shedding from the trailing edge of the stator blades, pulsating incoming flow to a rotor blade from passing stator blades, and flow separation from both suction and pressure sides of the rotor blades.

Nakamura, S.; Scott, J. N.

1993-01-01

128

Stator and Rotor Pole Combinations for Multi-Tooth Flux-Switching Permanent-Magnet Brushless AC Machines  

Microsoft Academic Search

A simple analytical method is developed for determining the optimal combination of stator pole and rotor pole numbers for a multi-tooth flux-switching permanent magnet (FSPM) machine, and the optimal design of the stator teeth for maximum torque. In addition, the rotor pole width and the split ratio are optimized by finite element analysis. The optimized multi-tooth FSPM machine exhibits a

J. T. Chen; Z. Q. Zhu; D. Howe

2008-01-01

129

Performance of a turbojet engine with adjustable first-stage turbine stator and variable-area exhaust nozzle  

NASA Technical Reports Server (NTRS)

The performance of a turbojet engine with a two-stage turbine, an adjustable first-stage turbine stator, and a variable-area exhaust nozzle was investigated at selected constant engine speeds and two simulated flight conditions. For the particular component characteristics of the engine investigated, little improvement in thrust levels of interest by use of an adjustable rather than an optimum fixed first-stage turbine stator.

Meyer, Carl L; Smith, Ivan D; Bloomer, Harry E

1953-01-01

130

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

131

Novel error sensing microphone arrays for active control of turbofan rotor/stator tones  

NASA Astrophysics Data System (ADS)

Active control of turbofan rotor/stator interaction tones is complicated by the simultaneous presence of multiple duct propagation modes. In-duct error sensing microphone arrays that can adequately resolve these modes typically require duct lengths that are incompatible with modern compact engine design. Two alternative approaches have been investigated. For inlet noise, an external linear array of microphones was positioned in the near/far radiation field transition region and weighted to provide error signals resolved either by duct mode or by radiation angle. For the exhaust, radially spaced microphones have been placed on duct bifurcation panels to provide supplemental radial-mode resolution. The concepts were tested in combination with an adaptive segmented liner in a static duct and as part of an active stator-vane system in the ANCF research facility at NASA/Glenn Research Center. [Work sponsored by NASA/Langley Research Center.

Walker, Bruce E.; Hersh, Alan S.; Rice, Edward J.; Sutliff, Daniel L.

2003-10-01

132

Wide frequency range characterization of rotating machine stator-core laminations  

NASA Astrophysics Data System (ADS)

In this paper a new method of stator-core lamination characterization, aimed at studying magnetic field in the vicinity of a machine, is proposed. This characterization, made with small signals over a wide frequency range, is useful to study high frequency magnetic behavior of motors fed by PWM static converters. Small minor hysteresis loops of magnetic steel are assimilated to ellipses and, neglecting anisotropy, any point of a stator-core lamination is characterized by two local parameters: the relative permeability and the resistivity. The proposed method consists in measuring the impedance of a test coil over a wide frequency range by an impedance analyzer and in comparing experimental results to theoretical predictions based on magnetic field diffusion equation. An algorithm yields values of local relative permeability and resistivity from inductance measurements and experimental values of resistances are used to control the result quality.

Roger, D.; Ninet, O.; Duchesne, S.

2003-08-01

133

Application of Synthetic Jets to Reduce Stator Flow Separation in a Low Speed Axial Compressor  

NASA Technical Reports Server (NTRS)

Flow control using synthetic jet injection has been applied in a low speed axial compressor. The synthetic jets were applied from the suction surface of a stator vane via a span-wise row of slots pitched in the streamwise direction. Actuation was provided externally from acoustic drivers coupled to the vane tip via flexible tubing. The acoustic resonance characteristics of the system, and the resultant jet velocities were obtained. The effects on the separated flow field for various jet velocities and frequencies were explored. Total pressure loss reductions across the vane passage were measured. The effect of synthetic jet injection was shown to be comparable to that of pulsatory injection with mass addition for stator vanes which had separated flow. While only a weak dependence of the beneficial effect was noted based on the excitation frequency, a strong dependence on the amplitude was observed at all frequencies.

Braunscheidel, Edward P.; Culley, Dennis E.; Zaman, Khairul B.M.Q.

2008-01-01

134

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

135

Secondary flow spanwise deviation model for the stators of NASA middle compressor stages  

NASA Technical Reports Server (NTRS)

A model of the spanwise variation of deviation for stator blades is presented. Deviation is defined as the difference between the passage mean flow angle and the metal angle at the outlet of a blade element of an axial compressor stage. The variation of deviation is taken as the difference above or below that predicted by blade element, (i.e., two-dimensional) theory at any spanwise location. The variation of deviation is dependent upon the blade camber, solidity and inlet boundary layer thickness at the hub or tip end-wall, and the blade channel aspect ratio. If these parameters are known or can be calculated, the model provides a reasonable approximation of the spanwise variation of deviation for most compressor middle stage stators operating at subsonic inlet Mach numbers.

Roberts, W. B.; Sandercock, D. M.

1984-01-01

136

Acoustic Scattering by Three-Dimensional Stators and Rotors Using the SOURCE3D Code. Volume 1; Analysis and Results  

NASA Technical Reports Server (NTRS)

This report provides a study of rotor and stator scattering using the SOURCE3D Rotor Wake/Stator Interaction Code. SOURCE3D is a quasi-three-dimensional computer program that uses three-dimensional acoustics and two-dimensional cascade load response theory to calculate rotor and stator modal reflection and transmission (scattering) coefficients. SOURCE3D is at the core of the TFaNS (Theoretical Fan Noise Design/Prediction System), developed for NASA, which provides complete fully coupled (inlet, rotor, stator, exit) noise solutions for turbofan engines. The reason for studying scattering is that we must first understand the behavior of the individual scattering coefficients provided by SOURCE3D, before eventually understanding the more complicated predictions from TFaNS. To study scattering, we have derived a large number of scattering curves for vane and blade rows. The curves are plots of output wave power divided by input wave power (in dB units) versus vane/blade ratio. Some of these plots are shown in this report. All of the plots are provided in a separate volume. To assist in understanding the plots, formulas have been derived for special vane/blade ratios for which wavefronts are either parallel or normal to rotor or stator chords. From the plots, we have found that, for the most part, there was strong transmission and weak reflection over most of the vane/blade ratio range for the stator. For the rotor, there was little transmission loss.

Meyer, Harold D.

1999-01-01

137

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

138

An electrostatic lower stator axial-gap polysilicon wobble motor. II. Fabrication and performance  

Microsoft Academic Search

For pt. I see ibid., vol. 7, no. 1, p. 79-86 (1998). This paper presents the fabrication and first performance characteristics of electrostatically driven axial-gap polysilicon wobble motors. The fabrication is based on a four mask process using polysilicon surface-micromachining techniques. Three twelve-stator-pole wobble motor designs have been realized with rotor radii of 50 and 100 ?m. Motors have been

Rob Legtenberg; Erwin Berenschot; John van Baar; Miko Elwenspoek

1998-01-01

139

An electrostatic lower stator axial-gap polysilicon wobble motor. I. Design and modeling  

Microsoft Academic Search

This paper presents design issues and a theoretical model of electrostatically driven axial-gap polysilicon wobble motors. The motor design benefits from large axial rotor-to-stator overlap and large gear ratios, and motor designs with rotor radii of 50 and 100 ?m are capable of generating torques in the nanoNewtonmeter range at high electrostatic fields. Because of the large gear ratio, smaller

Rob Legtenberg; Erwin Berenschot; John van Baar; Miko Elwenspoek

1998-01-01

140

An electrostatic lower stator axial-gap polysilicon wobble motor part II: fabrication and performance  

Microsoft Academic Search

For pt. I see ibid., vol. 7, no. 1, p. 79-86 (1998). This paper presents the fabrication and first performance characteristics of electrostatically driven axial-gap polysilicon wobble motors. The fabrication is based on a four mask process using polysilicon surface-micromachining techniques. Three twelve-stator-pole wobble motor designs have been realized with rotor radii of 50 and 100 ¿m. Motors have been

Rob Legtenberg; Erwin Berenschot; Baar van John; Miko Elwenspoek

1998-01-01

141

Active Closed-Loop Stator Vane Flow Control Demonstrated in a Low-Speed Multistage Compressor  

NASA Technical Reports Server (NTRS)

Closed-loop flow control was successfully demonstrated on the surface of stator vanes in NASA Glenn Research Center's Low-Speed Axial Compressor (LSAC) facility. This facility provides a flow field that accurately duplicates the aerodynamics of modern highly loaded compressors. Closed-loop active flow control uses sensors and actuators embedded within engine components to dynamically alter the internal flow path during off-nominal operation in order to optimize engine performance and maintain stable operation.

Bright, Michelle M.; Culley, Dennis E.; Strazisar, Anthony J.

2004-01-01

142

Temperature-Aging Tests on Class-A-Insulated Fractional-Horsepower Motor Stators  

Microsoft Academic Search

Temperature-aging data are presented on class-A-insulated fractional-horsepower motor stators, determined at 200, 160, and 135 degrees centigrade. Of particular interest is the relative aging time to failure at the different temperatures and the resultant temperature-aging curve. This curve shows a slope of 10 to 15 degrees centigrade increase in temperature to halve the aging time to failure in the temperature

J. A. Scott; B. H. Thompson

1942-01-01

143

Evaluation of Nonlinear Rotor Wake\\/Stator Interaction by using Time Domain Chorochronic Solver  

Microsoft Academic Search

Rotor wake interactions with stators is an important aspect in turbomachinery noise generation. This paper deals with the time lagged periodic boundary condition (chorochronic periodicity) used in time domain Navier-Stokes equations solvers and its advantages\\/drawbacks over frequency domain linearized N-S equations solvers. The time lag periodic b.c. is used to solve the nonlinear three dimensional N-S equations using realizable k-epsilon

Martin Olausson; Lars-Erik Eriksson; Stéphane Baralon

144

VALIDATION OF 3D ROTOR-STATOR URANS IN AUTOMOTIVE ENGINE COOLING FAN SYSTEMS  

Microsoft Academic Search

A low-speed rotor-stator assembly has been modeled using a full 3-D Navier-Stokes solver with an unsteady in- terface. The predicted integral performances are first compared to the measurements on the Michigan State Uni- versity fan test facility. This numerical model has then been evaluated using detailed experimental data collected using hot-wire anemometry techniques. Two specific probes, a conventional X-probe and

Manuel Henner; Stéphane Moreau; Douglas Neal; Jérôme de Laborderie

145

Acoustic Reflection and Transmission of 2-Dimensional Rotors and Stators, Including Mode and Frequency Scattering Effects  

NASA Technical Reports Server (NTRS)

A reduced order modeling scheme has been developed for the unsteady acoustic and vortical coupling between blade rows of a turbomachine. The essential behavior of the system is governed by modal scattering coefficients (i.e., reflection and transmission coefficients) of the rotor, stator, inlet and nozzle, which are calculated as if they were connected to non-reflecting ducts. The objective of this report is to identify fundamental behavior of these scattering coefficients for a better understanding of the role of blade row reflection and transmission in noise generation. A 2D flat plate unsteady cascade model is used for the analysis with the expectation that the general behavior presented herein will carry over to models that include more realistic flow and geometry. It is shown that stators scatter input waves into many modes at the same frequency whereas rotors scatter on frequency, or harmonic order. Important cases are shown here the rotor reflection coefficient is greater than unity; a mode at blade passing frequency (BPF) traveling from the stator with unit sound power is reflected by the rotor with more than unit power at 2xBPF and 3xBPE Analysis is presented to explain this unexpected phenomenon. Scattering curves are presented in a format chosen for design use and for physical interpretation. To aid in interpretation of the curves, formulas are derived for special condition where waveforms are parallel to perpendicular to the rotor.

Hanson, Donald B.

1999-01-01

146

Two-stage fan. 4: Performance data for stator setting angle optimization  

NASA Technical Reports Server (NTRS)

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 lb/sec (83.55 kg/sec) and a 1st-stage rotor tip speed of 1450 ft/sec (441.96 in/sec). Performance was obtained at 70,100, and 105 percent of design speed with different combinations of 1st-stage and 2nd-stage stator settings. One combination of settings, other than design, was common to all three speeds. At design speed, a 2.0 percentage point increase in stall margin was obtained at the expense of a 1.3 percentage point efficiency decrease. At 105 percent speed, efficiency was improved by 1.8 percentage points but stall margin decreased 4.7 percentage points. At 70 percent speed, no change in stall margin or operating line efficiency was obtained with stator resets although considerable speed-flow requlation occurred.

Burger, G. D.; Keenan, M. J.

1975-01-01

147

Active Flow Separation Control of a Stator Vane Using Surface Injection in a Multistage Compressor Experiment  

NASA Technical Reports Server (NTRS)

Micro-flow control actuation embedded in a stator vane was used to successfully control separation and improve near stall performance in a multistage compressor rig at NASA Glenn. Using specially designed stator vanes configured with internal actuation to deliver pulsating air through slots along the suction surface, a research study was performed to identify performance benefits using this microflow control approach. Pressure profiles and unsteady pressure measurements along the blade surface and at the shroud provided a dynamic look at the compressor during microflow air injection. These pressure measurements lead to a tracking algorithm to identify the onset of separation. The testing included steady air injection at various slot locations along the vane. The research also examined the benefit of pulsed injection and actively controlled air injection along the stator vane. Two types of actuation schemes were studied, including an embedded actuator for on-blade control. Successful application of an online detection and flow control scheme will be discussed. Testing showed dramatic performance benefit for flow reattachment and subsequent improvement in diffusion through the use of pulsed controlled injection. The paper will discuss the experimental setup, the blade configurations, and preliminary CFD results which guided the slot location along the blade. The paper will also show the pressure profiles and unsteady pressure measurements used to track flow control enhancement, and will conclude with the tracking algorithm for adjusting the control.

Culley, Dennis E.; Bright, Michelle M.; Prahst, Patricia S.; Strazisar, Anthony J.

2003-01-01

148

Aerodynamic performances of three fan stator designs operating with rotor having tip speed of 337 meters per second and pressure ratio of 1.54. 1: Experimental performance  

NASA Technical Reports Server (NTRS)

The aerodynamic performances of four stator-blade rows are presented and evaluated. The aerodynamic designs of two of these stators were compromised to reduce noise, a third design was not. On a calculated operating line passing through the design point pressure ratio, the best stator had overall pressure-ratio and efficiency decrements of 0.031 and 0.044, respectively, providing a stage pressure ratio of 1.483 and efficiency of 0.865. The other stators showed some correctable deficiencies due partly to the design compromises for noise. In the end-wall regions blade-element losses were significantly less for the shortest chord studied.

Gelder, T. F.

1980-01-01

149

Moteurs piézo-électriques à onde progressive : II. Modélisation analytique bidimensionnelle du contact stator/rotor  

NASA Astrophysics Data System (ADS)

This second paper, out of three, devoted to the theoretical modeling of traveling wave type ultrasonic motors, focuses especially on the stator/rotor contact problem. The first part gives a short description of the specific test bench, which has been developed by our laboratory, in order to perform the acquisition of the stator/rotor interface geometry. Then an analytical approach is shown, based on the general solution of the bidimensional elastic problem in terms of Fourier integrals. This approach allows to figure the influence of the interface mechanical and geometric parameters. After a long calculation, the contact area and the pressure distribution are obtained. The good correlation between numerical simulations (performed on ANSYS finite element code with calculation time of about one hour) and our analytical modeling is then pointed out. Finally, a new software named C.U.B.I.C. (Contact Unilatéral entre Bicouches et Indenteurs Continus) and based on the previous theoretical contact model is presented. It allows both the contact area, and the pressure distribution to be obtained as well as a visualization of the geometric configuration of the stator/rotor interface with respect to the axial preload. By using the calculations performed by C.U.B.I.C. as input parameters of C.A.S.I.M.M.I.R.E. software (Conception Assistée par la SImulation Mécanique des MIcromoteurs REsonnants), previously developed by our laboratory, a rotative piezomotor can be characterized and optimized in a few seconds. Dans ce second article, consacré à la modélisation théorique des moteurs piézo-électriques à onde progressive, on s'intéresse plus particulièrement au mécanisme de contact à l'interface stator/rotor. La première partie présente une rapide description de la plateforme d'essais, développée par notre laboratoire afin de définir précisement la géometrie de l'interface stator/rotor. Ensuite, nous développons le modèle analytique du contact, basé sur la solution générale du problème bidimensionnelle élastique en termes d'intégrales de Fourier. Celui-ci met en évidence l'influence des paramètres mécaniques et géometriques de l'interface et permet notamment l'acquisition de la zone de contact et de la distribution de pression normale. Cette approche analytique est ensuite validée de manière très précise, à partir des simulations numériques effectuées à partir du code éléments finis ANSYS. Enfin, un logiciel baptisé C.U.B.I.C. (Contact Unilatéral entre Bicouches et Indenteurs Continus), basé sur le modèle de contact précédent, est rapidement présenté. Il permet d'accéder, en quelques secondes, à la visualisation de la zone de contact et de la distribution de pression à l'interface stator/rotor en fonction de l'effort de précontrainte. Le logiciel C.U.B.I.C. calcule les paramètres d'entrée des modèles précédemment développés dans le logiciel C.A.S.I.M.M.I.R.E. (Conception Assistée par la SImulation des Mécaniques des MIcromoteurs REsonnants), et se subtitue avantageusement au code éléments finis ANSYS. La complémentarité des deux logiciels développés au L.M.A.R.C. autorise actuellement le dimensionnement optimal d'un prototype au stade de l'avant-projet.

Le Moal, P.; Minotti, P.; Ferreira, A.; Duffaud, J.

1996-10-01

150

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

151

Nonlinear phenomena, bifurcations, and routes to chaos in an asymmetrically supported rotor-stator contact system  

NASA Astrophysics Data System (ADS)

The efficiency of rotating machines can be improved via precisely manufactured bearings with reduced clearances; consequently, the proclivity for rotor-stator contact is increased. A common model used to investigate rotor-stator contact in previous studies is the two degree-of-freedom (DOF) rotor with symmetric support stiffness, where the contact assumes a linear elastic normal restoring force proportional to the rotor-stator interference and a tangential dry Coulomb friction force. Switching between the contacting and non-contacting states creates strong nonlinearity in the equations of motion, and the dynamic response displays a rich profile of behaviors including periodic, quasiperiodic, and chaotic responses via period-doubling, sudden transitions, quasiperiodicity, and intermittency. For the first time, this work emphasizes an asymmetric support stiffness matrix with cross-coupling between the x and y direction stiffnesses. The influence of support asymmetry on the nonlinear rotor response is shown using rotor orbits, frequency spectra, Poincaré sections, and bifurcation diagrams. It is found that the cross-coupling stiffness coefficient kxy has negligible effect on the dynamic response until its magnitude is on the same order as the direct stiffness coefficients. Direct stiffness coefficient asymmetry is shown to affect the rotor's response, where even small asymmetries can qualitatively change the response. Additionally, the importance of including gravity is investigated, and a method is provided for determining the threshold shaft speed above which gravity can be ignored. The dominant route to chaos is period-doubling for the parameters considered here, though other routes to chaos are seen such as a direct transition from periodic to chaotic motion. Finally, observations pertaining to rotor modeling, design, and fault diagnostics are discussed.

Varney, Philip; Green, Itzhak

2015-02-01

152

An unconditionally stable Runge-Kutta method for unsteady rotor-stator interaction  

NASA Astrophysics Data System (ADS)

A quasi-three-dimensional analysis has been developed for unsteady rotor-stator interaction in turbomachinery. The analysis solves the unsteady Euler or thin-layer Navier-Stokes equations in a body-fitted coordinate system. It accounts for the effects of rotation, radius change, and stress-surface thickness. The Baldwin-Lomax eddy-viscosity model is used for turbulent flows. The equations are integrated in time using an explicit four-stage Runge-Kutta scheme with a constant time step. Implicit residual smoothing is used to increase the stability limit of the time-accurate computations. The scheme is described, and stability and accuracy analyses are given.

Chima, Rodrick V.; Jorgenson, Philip C. E.

1989-04-01

153

Optimal design of stator interior permanent magnet machine based on finite element analysis  

NASA Astrophysics Data System (ADS)

This article investigates the optimal design of the stator interior permanent magnet (SIPM) machine for sinusoidal electromotive force (EMF) waveform. The key is to develop a design approach for the rotor pole arc and rotor skewing of the SIPM machine in such a way that total harmonic distortion of the EMF waveform is the minimum. The two-dimensional finite element analysis is employed to calculate the magnetic field distributions in terms of the different rotor pole arc and rotor skewing angle. A prototype of three-phase 12/10-pole SIPM machine is used for exemplification. Both the predicted and measured results are given to illustrate the proposed machine.

Zhang, Jianzhong; Cheng, Ming; Hua, Wei

2009-04-01

154

Compact piezoelectric micromotor with a single bulk lead zirconate titanate stator  

NASA Astrophysics Data System (ADS)

The advance of micro/nanotechnology promotes the development of micromotors in recent years. In this article, a compact piezoelectric ultrasonic micromotor with a single bulk lead zirconate titanate stator is proposed. A traveling wave is generated by superposition of bending modes with 90° phase difference excited by d15 inverse piezoelectric effects. The operating principle simplifies the system structure significantly, and provides a miniaturization solution. A research prototype with the size of 0.75× 0.75×1.55 mm is developed. It can produce start-up torque of 0.27?Nmand maximum speed of 2760 r/min at 14RMS.

Yan, Liang; Lan, Hua; Jiao, Zongxia; Chen, Chin-Yin; Chen, I.-Ming

2013-04-01

155

Comparison of calculated and experimental cascade performance for controlled-diffusion compressor stator blading  

NASA Technical Reports Server (NTRS)

The mid-span section of a previously reported controlled-diffusion compressor stator has been experimentally evaluated in cascade. Measurements are taken over a range of incidence angles for blade chord Reynolds numbers from 470,000 to 690,000. Blade chord length is 12.7 cm, aspect ratio is 2.0, and solidity is 1.67. Measurements include conventional cascade performance parameters as well as blade surface pressures. Computations are made for the inviscid flow field, surface boundary layers, and loss for several of the blade inlet angle conditions, are compared against corresponding data.

Sanger, N. L.; Shreeve, R. P.

1986-01-01

156

Low Speed, 2-D Rotor/Stator Active Noise Control at the Source Demonstration  

NASA Technical Reports Server (NTRS)

Wake/blade-row interaction noise produced by the Annular Cascade Facility at Purdue University has been modeled using the LINFLO analysis. Actuator displacements needed for complete cancellation of the propagating acoustic response modes have been determined, along with the associated actuator power requirements. As an alternative, weighted least squares minimization of the total far-field sound power using individual actuators has also been examined. Attempts were made to translate the two-dimensional aerodynamic results into three-dimensional actuator requirements. The results lie near the limit of present actuator technology. In order to investigate the concept of noise control at the source for active rotor/stator noise control at the source, various techniques for embedding miniature actuators into vanes were examined. Numerous miniature speaker arrangements were tested and analyzed to determine their suitability as actuators for a demonstration test in the Annular Cascade Facility at Purdue. The best candidates demonstrated marginal performance. An alternative concept to using vane mounted speakers as control actuators was developed and tested. The concept uses compression drivers which are mounted externally to the stator vanes. Each compression driver is connected via a tube to an air cavity in the stator vane, from which the driver signal radiates into the working section of the experimental rig. The actual locations and dimensions of the actuators were used as input parameters for a LINFLO computational analysis of the actuator displacements required for complete cancellation of tones in the Purdue experimental rig. The actuators were designed and an arrangement determined which is compatible with the Purdue experimental rig and instrumentation. Experimental tests indicate that the actuators are capable of producing equivalent displacements greater than the requirements predicted by the LINFLO analysis. The acoustic output of the actuators was also found to be unaffected by the presence of air flow representative of the Purdue experimental rig. A test of the active noise control at the source concept for rotor/stator active noise control was demonstrated. This 2-D test demonstrated conclusively the simultaneous reduction of two acoustic modes. Reductions of over 10 dB were obtained over a wide operating range.

Simonich, John C.; Kousen, Ken A.; Zander, Anthony C.; Bak, Michael; Topol, David A.

1997-01-01

157

Predicting the Rotor-Stator Interaction Acoustics of a Ducted Fan Engine  

NASA Technical Reports Server (NTRS)

A Navier-Stokes computation is performed for a ducted-fan configuration with the goal of predicting rotor-stator noise generation without having to re- to heuristic modeling. The calculated pressure field in the inlet region is decomposed into classical infinite-duct, modes, which are then used in either a hybrid finite-element /Kirchhoff surface method or boundary integral equation method to calculate the far field noise. Comparisons with experimental data are presented, including rotor wake surveys and far field sound pressure levels for 2 blade passage frequency (BPF) tones.

Biedron, Robert T.; Rumsey, Christopher L.; Podboy, Gary G.; Dunn, M. H.

2001-01-01

158

Numerical investigation of base-setting of stator's stagger angles for a 15-stage axial-flow compressor  

NASA Astrophysics Data System (ADS)

A 15-stage axial-flow compressor utilized in steel industry was studied in this paper. All the stator's stagger angles of the compressor are variable to ensure the multistage compressor operate effectively within a wide range of flow rate and meanwhile satisfy the demand for sufficient pressure ratio, adiabatic efficiency and stall margin. Three in all different base-settings of stator's stagger angles were presented and commercial CFD software was applied to obtain the overall performance characteristics. The results showed that both of the optimized base-settings improved the performances both in summer and winter conditions, although the adiabatic efficiency was somewhat decreased. Taking incidence angle and stage loading into consideration, differences among the three cases were analyzed in detail. On the basis of numerical computations, the performance could be effectively improved through adjusting the base-setting of stator's stagger angles.

Chang, Hao; Zhao, Weiguang; Jin, Donghai; Peng, Zeyan; Gui, Xingmin

2014-02-01

159

Basic Studies on Methods of In-Plane Eddy Current Analysis for Stator Core-Ends of Turbine Generators  

NASA Astrophysics Data System (ADS)

In this paper, we investigate the methods of eddy current analysis for stator core-ends of turbine generators from both results of experiment and finite element analysis. First, the 3-D finite element analysis considering the lamination of the core is applied to the simple model that simulates the end part of the turbine generator. The calculated losses and flux distributions caused by the perpendicular flux are compared with the measurement to verify the validity of the calculation method. The measured and calculated results agree well. Next, the calculation method is applied to the 250MVA class turbine generator with the considerations of the laminated stator core. The field and loss distributions at stator core-ends of the turbine generators are clarified.

Yamazaki, Katsumi; Watanabe, Yuta; Tada, Shin; Mogi, Hisashi; Kaido, Chikara; Kanao, Shinichi; Takahashi, Kazuhiko; Ide, Kazumasa; Hattori, Ken'ichi; Nakahara, Akihito

160

Application of the largest Lyapunov exponent for the diagnosis of rotor-to-stator rub in rotating machinery  

NASA Astrophysics Data System (ADS)

Vibration based diagnosis has played a vital role in the crucial analysis of faults in rotating machinery. The conventional vibration techniques currently being used in the industry are however not able to effectively identify nonlinear or complex signals due to, for example, rotor-to-stator rub. This paper reports on the application of the largest Lyapunov Exponent ?1 to diagnose the severity of rotor-to-stator rub in rotating machinery. The method of time delay was employed to reconstruct the vibration signal obtained from numerical simulation of a Jeffcott rotor subjected to rotor-to-stator rub. Numerical results show clear correlation between the increase of rub severity with the invariant quantity ?1 investigated in this work. Two different algorithms for the computation of ?1 were employed in this research, namely the Wolf algorithm and the Rosenstein algorithm.

ChangJie, Colin Heng; Inayat-Hussain, Jawaid I.

2014-10-01

161

Measurement of the temperature of a stator winding with fiber-optic sensors in bench tests of a turbogenerator  

SciTech Connect

The temperature of the elementary conductors of the stator winding of a 225 MW turbogenerator has been measured using miniature fiber-optic sensors, built in to the winding during manufacture. This is the first time that practical bench tests have been made in Russian electrical machine construction practice. The results of the experiment are used as the initial data for determining important parameters of the construction of turbogenerators with air cooling, namely, the thermal conductivity of the body insulation in the slot, and the heat-transfer coefficient in the front parts of the stator winding.

Gurevich, E. I., E-mail: gur_v@rambler.ru [St. Petersburg State Polytechnic University (Russian Federation); Lyamin, A. A. ['Electrosila' branch of JSC 'Power Machines' (Russian Federation); Shelemba, I. S. [Company 'Inversiya-Sensor' (Russian Federation)

2010-09-15

162

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

NASA Technical Reports Server (NTRS)

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 experimental technique to the complex environment of internal flows in turbomachines. First, there is a short explanation of the physics of the PSP technique and a discussion of calibration methods for pressure sensitive paint in the turbomachinery environment. A description of the image conversion process follows. The recorded image of the stator vane pressure field is skewed due to the limited optical access and must be converted to the meridional plane projection for comparison with analytical predictions. The experimental results for seven operating conditions along an off-design rotational speed line are shown in a concise form, including performance map points, mindspan static tap pressure distributions, and vane suction side pressure fields. Then, a comparison between static tap and pressure sensitive paint data is discussed. Finally, the paper lists shortcomings of the pressure sensitive paint technology and lessons learned in this high-speed fan application.

Lepicovsky, Jan

1998-01-01

163

Flexibility within the Rotor and Stators of the Vacuolar H+-ATPase  

PubMed Central

The V-ATPase is a membrane-bound protein complex which pumps protons across the membrane to generate a large proton motive force through the coupling of an ATP-driven 3-stroke rotary motor (V1) to a multistroke proton pump (Vo). This is done with near 100% efficiency, which is achieved in part by flexibility within the central rotor axle and stator connections, allowing the system to flex to minimise the free energy loss of conformational changes during catalysis. We have used electron microscopy to reveal distinctive bending along the V-ATPase complex, leading to angular displacement of the V1 domain relative to the Vo domain to a maximum of ~30°. This has been complemented by elastic network normal mode analysis that shows both flexing and twisting with the compliance being located in the rotor axle, stator filaments, or both. This study provides direct evidence of flexibility within the V-ATPase and by implication in related rotary ATPases, a feature predicted to be important for regulation and their high energetic efficiencies. PMID:24312643

Song, Chun Feng; Papachristos, Kostas; Rawson, Shaun; Huss, Markus; Wieczorek, Helmut; Paci, Emanuele; Trinick, John; Harrison, Michael A.; Muench, Stephen P.

2013-01-01

164

Significance of the Electromagnetic Forces on the Mechanical Resonances of Stator Laminations  

NASA Astrophysics Data System (ADS)

The laminated structure of the stator core of fractional horsepower electric motors consists of plates of ferromagnetic materials that can have unusually large deformation coefficients when an electric field is applied. The influence of the compressive stresses is the cause of significant changes in the harmonics that can be explained by the effect of the stress on the harmonic content of the flux density waveform. Magnetostriction harmonics are important when considering the significant contribution to audible noise of electric motors. The significance of magnetostrictive forces increases when they excite the lamination plates around their mechanical resonances. The combined effects of the radial components of the electromagnetic forces and the magnetostrictive deformation can cause further problems of amplification of noise by setting the core and frame in motion. This study investigates the effects of magnetostrictive forces on the laminated mechanical structure of the stator core by referring to changes of the plate materials depending upon the heat treatments, magnetic properties, and the percentage of silicon alloying that were all considered as factors which modify the effects of magnetostriction.

Öztürk, C.; Bahadir, A.

1996-09-01

165

Investigation of the fluid flow in an isolated rotor-stator system with a peripheral opening  

NASA Astrophysics Data System (ADS)

This paper deals with an experimental, theoretical and numerical study of a turbulent flow with separated boundary layers between a rotor and a stator. The system is not subjected to any superimposed radial flow. The periphery of the cavity is opened to the atmosphere so that the solid body rotation for infinite discs is not always observed. Emphasis was placed on development of an asymptotic approach and a step-by-step method to compute the radial distribution of the core swirl ratio and the static pressure on the stator side. The theory also includes the radial and axial velocities in the core region. The numerical simulation has been conducted with the commercial CFD code Fluent 6.1. The k- ?SST turbulence model is used, with the assumption of 2D-axisymmetric and steady flow. CFD validations have been performed by comparison of the numerical results with the corresponding theoretical results. Numerical and experimental results are in good agreement with analytical solutions.

Debuchy, Roger; Abdel Nour, Fadi; Naji, Hassane; Bois, Gérard

2013-04-01

166

On Acoustic Source Specification for Rotor-Stator Interaction Noise Prediction  

NASA Technical Reports Server (NTRS)

This paper describes the use of measured source data to assess the effects of acoustic source specification on rotor-stator interaction noise predictions. Specifically, the acoustic propagation and radiation portions of a recently developed coupled computational approach are used to predict tonal rotor-stator interaction noise from a benchmark configuration. In addition to the use of full measured data, randomization of source mode relative phases is also considered for specification of the acoustic source within the computational approach. Comparisons with sideline noise measurements are performed to investigate the effects of various source descriptions on both inlet and exhaust predictions. The inclusion of additional modal source content is shown to have a much greater influence on the inlet results. Reasonable agreement between predicted and measured levels is achieved for the inlet, as well as the exhaust when shear layer effects are taken into account. For the number of trials considered, phase randomized predictions follow statistical distributions similar to those found in previous statistical source investigations. The shape of the predicted directivity pattern relative to measurements also improved with phase randomization, having predicted levels generally within one standard deviation of the measured levels.

Nark, Douglas M.; Envia, Edmane; Burley, Caesy L.

2010-01-01

167

The use of cowl camber and taper to reduce rotor/stator interaction noise  

NASA Technical Reports Server (NTRS)

The project had two specific technical objectives: (1) to develop a realistic three-dimensional model of tonal noise due to rotor/stator interaction, as the input field for predictions of diffraction and dissipation by a lined cowl; and (2) to determine whether the generator curve of that cowl, or duct, could be 'steered' to yield substantially lower values of propulsor noise along the engine's fore and aft open sectors. The more general and important aim of their research is to provide the commercial aircraft industry with a useful predictive tool to help it meet its noise-reduction goals. The work has produced a tractable and yet realistic model of rotor/stator interaction noise. The blades in the fan stage are radially divergent, twisted, and of realistically wide chords to match the high frequencies and speeds of the sound-production process. The resulting three-dimensional acoustic nearfield insonifies the interior wall of the diffracting cowl, whose shape, incidentally, does not affect fore or aft noise significantly (but other factors do).

Martinez, R.

1995-01-01

168

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

169

Fault Detection and Diagnosis in an Induction Machine Drive: A Pattern Recognition Approach Based on Concordia Stator Mean Current Vector  

Microsoft Academic Search

The aim of this paper is to study the feasibility of fault detection and diagnosis in a three-phase inverter feeding an induction motor. The proposed approach is a sensor-based technique using the mains current measurement. A localization domain made with seven patterns is built with the stator Concordia mean current vector. One is dedicated to the healthy domain and the

Demba Diallo; Mohamed El Hachemi Benbouzid; Denis Hamad; Xavier Pierre

2005-01-01

170

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

171

Measurement of the temperature of a stator winding with fiber-optic sensors in bench tests of a turbogenerator  

Microsoft Academic Search

The temperature of the elementary conductors of the stator winding of a 225 MW turbogenerator has been measured using miniature fiber-optic sensors, built in to the winding during manufacture. This is the first time that practical bench tests have been made in Russian electrical machine construction practice. The results of the experiment are used as the initial data for determining

E. I. Gurevich; A. A. Lyamin; I. S. Shelemba

2010-01-01

172

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

173

Design and control of a single stator dual PM rotors axial synchronous machine for hybrid electric vehicles  

Microsoft Academic Search

In this paper is presenting the preliminary designing and control of a synchronous machine with axial airgap single stator dual-rotor with permanent surface magnets and different pole pairs number, destined for hybrid electric vehicles (HEV) applications. For machine’s designing was used the equivalent magnetic circuits method that takes into account the saturation and dispersion of the magnetic field. The control

Lucian Nicolae Tutelea; Sorin Ioan Deaconu; Ion Boldea; Fabrizio Marignetti; Gabriel Nicolae Popa

2011-01-01

174

A kinematical/numerical analysis of rotor-stator interaction noise  

NASA Technical Reports Server (NTRS)

In this study, the unsteady, thin-layer Navier-Stokes equations are solved using a system of patched grids for a rotor-stator configuration of an axial turbine. The study examines the plurality of spinning modes that are present in such an interaction. The propagation of these modes is analyzed and appropriate grid spacing chosen in the far upstream and downstream regions to attenuate reflections from the computational boundaries. In addition, radiating boundary conditions are implemented based on the farfield acoustical behavior of the flow field. Results in the form of pressure amplitudes and the spectra of turbine tones are presented. Numerical results and experimental data are compared wherever possible. The numerical results are also shown to conform with the predictions of a kinematical analysis of the flowfield.

Rangwalla, Akil A.; Rai, Man Mohan

1990-01-01

175

A numerical analysis of tonal acoustics in rotor-stator interactions  

NASA Technical Reports Server (NTRS)

In this study, the unsteady, thin-layer, Navier-Stokes equations are solved using a system of patched grids for a rotor-stator configuration of an axial turbine. The study focuses on the plurality of spinning modes that are present in such an interaction. The propagation of these modes in the upstream and downstream regions is analyzed and compared with numerical results. It was found that the numerically calculated tonal acoustics could be affected by the type of numerical boundary conditions employed at the inlet and exit of the computational boundaries and the grid spacing in the upstream and downstream regions. Results in the form of surface pressure amplitudes and the spectra of turbine tones and their far field behavior are presented. Numerical results and experimental data are compared wherever possible. The 'mode-content' for different harmonics of blade-passage frequency is shown to conform with that predicted by a kinematical analysis.

Rangwalla, A. A.; Rai, M. M.

1993-01-01

176

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

2014-01-01

177

Flow visualization study of the horseshoe vortex in a turbine stator cascade  

NASA Technical Reports Server (NTRS)

Flow visualization techniques were used to show the behavior of the horseshoe vortex in a large scale turbine stator cascade. Oil drops on the end wall surface flowed in response to local shear stresses, indicating the limiting flow streamlines at the surface. Smoke injected into the flow and photographed showed time averaged flow behavior. Neutrally bouyant helium filled soap bubbles followed the flow and showed up on photographs as streaks, indicating the paths followed by individual fluid particles. Preliminary attempts to control the vortex were made by injecting air through control jets drilled in the end wall near the vane leading edge. Seventeen different hole locations were tested, one at a time, and the effect of the control jets on the path follwed by smoke in the boundary layer was recorded photographically.

Gaugler, R. E.; Russell, L. M.

1982-01-01

178

Estimating the remaining service life of asphalt-mica stator insulation  

SciTech Connect

Synchronous generators were manufactured with asphalt bonded, mica flake insulation from 1917 to the 1950's. 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 and hydro synchronous generators on the American Electric Power system and laboratory tests on over 30 spare asphalt-mica stator bars and coils at AEP's Dolan Laboratory. The paper clearly shows that a straightforward ac overpotential test and a simple graphical evaluation and analysis can be used to confidently determine the remaining service life of asphalt bonded, mica flake insulated synchronous generators that have been well maintained and operated within design limits.

Timperley, J.E.; Michalec, J.R. (American Electric Power Service Corp., Columbus, OH (United States))

1994-12-01

179

Magnetic Flux Compression Using Detonation Plasma Armatures and Superconductor Stators: Integrated Propulsion and Power Applications  

NASA Technical Reports Server (NTRS)

This presentation discusses the use of magnetic flux compression for space flight applications as a propulsion and other power applications. The qualities of this technology that make it suitable for spaceflight propulsion and power, are that it has high power density, it can give multimegawatt energy bursts, and terawatt power bursts, it can produce the pulse power for low impedance dense plasma devices (e.g., pulse fusion drivers), and it can produce direct thrust. The issues of a metal vs plasma armature are discussed, and the requirements for high energy output, and fast pulse rise time requires a high speed armature. The plasma armature enables repetitive firing capabilities. The issues concerning the high temperature superconductor stator are also discussed. The concept of the radial mode pulse power generator is described. The proposed research strategy combines the use of computational modeling (i.e., magnetohydrodynamic computations, and finite element modeling) and laboratory experiments to create a demonstration device.

Litchford, Ron; Robertson, Tony; Hawk, Clark; Turner, Matt; Koelfgen, Syri

1999-01-01

180

EEMD-based wind turbine bearing failure detection using the generator stator current homopolar component  

NASA Astrophysics Data System (ADS)

Failure detection has always been a demanding task in the electrical machines community; it has become more challenging in wind energy conversion systems because sustainability and viability of wind farms are highly dependent on the reduction of the operational and maintenance costs. Indeed the most efficient way of reducing these costs would be to continuously monitor the condition of these systems. This allows for early detection of the generator health degeneration, facilitating a proactive response, minimizing downtime, and maximizing productivity. This paper provides then an assessment of a failure detection techniques based on the homopolar component of the generator stator current and attempts to highlight the use of the ensemble empirical mode decomposition as a tool for failure detection in wind turbine generators for stationary and non-stationary cases.

Amirat, Yassine; Choqueuse, Vincent; Benbouzid, Mohamed

2013-12-01

181

Two-dimensional cold-air cascade study of a film-cooled turbine stator blade. 1: Experimental results of pressure-surface film cooling tests  

NASA Technical Reports Server (NTRS)

The effect of film coolant ejection from the pressure side of a stator blade was determined in a two-dimensional cascade. Stator exit surveys were made for each of six rows of coolant holes. Successive multirow tests were made with two, three, four, five, and six rows of coolant holes open. The results of the multirow tests are compared with the predicted multirow performance obtained by adding the single-row data. Results are presented in terms of stator primary-air efficiency as a function of coolant fraction.

Moffitt, T. P.; Prust, H. W., Jr.; Bartlett, W. M.

1974-01-01

182

Backward Precessional Whip and Whirl for a Two Point Rubbing Contact Model of a Rigid Rotor Supported by an Elastically Supported Rigid Stator  

E-print Network

The present work investigates the phenomena of whip and whirl for a rigid rotor contacting at two bearing locations. The idea originated from an anemometer consisting of a rotor with an elastically supported stator undergoing the phenomena of dry...

Kumar, Dhruv Dileep

2011-10-21

183

Analytical Computation of the Full Load Magnetic Losses in the Soft Magnetic Composite Stator of High-Speed Slotless Permanent Magnet Machines  

Microsoft Academic Search

This paper presents an analytical model for predicting the stator full load magnetic losses in high-speed slotless permanent-magnet machines with surface-mounted magnets on the rotor and a stator core made of isotropic and conductive soft magnetic composite material (SMC). The losses are derived from the computation of the two-dimensional magnetic field distribution created by the rotor magnets, the currents in

Ahmed Chebak; Philippe Viarouge; Jérôme Cros

2009-01-01

184

Torque Generation in F 1ATPase Devoid of the Entire Amino-Terminal Helix of the Rotor That Fills Half of the Stator Orifice  

Microsoft Academic Search

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

Ayako Kohori; Ryohei Chiwata; Shou Furuike; Katsuyuki Shiroguchi; Kengo Adachi; Masasuke Yoshida; Kazuhiko Kinosita Jr.

2011-01-01

185

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

186

Vibration analysis of cracked rotor sliding bearing system with rotor-stator rubbing by harmonic wavelet transform  

NASA Astrophysics Data System (ADS)

In this paper, the vibration of a cracked rotor sliding bearing system with rotor-stator rubbing is investigated using harmonic wavelet transform (HWT). Three non-linear factors, non-linear oil film forces, rotor-stator rubbing and the presence of crack, are taken into account. So the non-linear behavior of the rotor will be much more complex. According to Newmark method, the dynamic response of the rotor is calculated. Using HWT method, the effect of these non-linear factors is analyzed simultaneously in both time and frequency domain. The numerical simulated result shows that HWT will be available to analyze this multi-non-linear factors rotor effectively and can reveal the exact fault characteristics in detail.

Wan, Fangyi; Xu, Qingyu; Li, Songtao

2004-04-01

187

An extraction of the dominant rotor-stator interaction modes by the use of Proper Orthogonal Decomposition (POD)  

Microsoft Academic Search

The Proper Orthogonal Decomposition method is applied to the instantaneous velocity field within the rotor-stator inter-row\\u000a region of a high-speed high-pressure centrifugal compressor. The processed data come from experiments and numerical simulations.\\u000a In comparison with a Fourier transform, the POD gives the best modal approximation for both initial fields, in terms of the\\u000a energy expressed on any given number of

N. Rochuon; I. Trébinjac; G. Billonnet

2006-01-01

188

Measurement of the temperature of a stator winding with fiber-optic sensors in bench tests of a turbogenerator  

Microsoft Academic Search

The temperature of the elementary conductors of the stator winding of a 225 MW turbogenerator has been measured using miniature\\u000a fiber-optic sensors, built in to the winding during manufacture. This is the first time that practical bench tests have been\\u000a made in Russian electrical machine construction practice. The results of the experiment are used as the initial data for determining

É. I. Gurevich; A. A. Lyamin; I. S. Shelemba

2010-01-01

189

Cyclic Di-GMP-Mediated Repression of Swarming Motility by Pseudomonas aeruginosa PA14 Requires the MotAB Stator.  

PubMed

The second messenger cyclic diguanylate (c-di-GMP) plays a critical role in the regulation of motility. In Pseudomonas aeruginosa PA14, c-di-GMP inversely controls biofilm formation and surface swarming motility, with high levels of this dinucleotide signal stimulating biofilm formation and repressing swarming. P. aeruginosa encodes two stator complexes, MotAB and MotCD, that participate in the function of its single polar flagellum. Here we show that the repression of swarming motility requires a functional MotAB stator complex. Mutating the motAB genes restores swarming motility to a strain with artificially elevated levels of c-di-GMP as well as stimulates swarming in the wild-type strain, while overexpression of MotA from a plasmid represses swarming motility. Using point mutations in MotA and the FliG rotor protein of the motor supports the conclusion that MotA-FliG interactions are critical for c-di-GMP-mediated swarming inhibition. Finally, we show that high c-di-GMP levels affect the localization of a green fluorescent protein (GFP)-MotD fusion, indicating a mechanism whereby this second messenger has an impact on MotCD function. We propose that when c-di-GMP level is high, the MotAB stator can displace MotCD from the motor, thereby affecting motor function. Our data suggest a newly identified means of c-di-GMP-mediated control of surface motility, perhaps conserved among Pseudomonas, Xanthomonas, and other organisms that encode two stator systems. PMID:25349157

Kuchma, S L; Delalez, N J; Filkins, L M; Snavely, E A; Armitage, J P; O'Toole, G A

2015-02-01

190

Feasibility of using PZT actuators to study the dynamic behavior of a rotating disk due to rotor-stator interaction.  

PubMed

In this paper, PZT actuators are used to study the dynamic behavior of a rotating disk structure due to rotor-stator interaction excitation. The disk is studied with two different surrounding fluids-air and water. The study has been performed analytically and validated experimentally. For the theoretical analysis, the natural frequencies and the associated mode shapes of the rotating disk in air and water are obtained with the Kirchhoff-Love thin plate theory coupled with the interaction with the surrounding fluid. A model for the Rotor Stator Interaction that occurs in many rotating disk-like parts of turbomachinery such as compressors, hydraulic runners or alternators is presented. The dynamic behavior of the rotating disk due to this excitation is deduced. For the experimental analysis a test rig has been developed. It consists of a stainless steel disk (r = 198 mm and h = 8 mm) connected to a variable speed motor. Excitation and response are measured from the rotating system. For the rotating excitation four piezoelectric patches have been used. Calibrating the piezoelectric patches in amplitude and phase, different rotating excitation patterns are applied on the rotating disk in air and in water. Results show the feasibility of using PZT to control the response of the disk due to a rotor-stator interaction. PMID:25004151

Presas, Alexandre; Egusquiza, Eduard; Valero, Carme; Valentin, David; Seidel, Ulrich

2014-01-01

191

Electromagnetic Radial Forces in a Hybrid Eight-Stator-Pole, Six-Rotor-Pole Bearingless Switched-Reluctance Motor  

NASA Technical Reports Server (NTRS)

Analysis and experimental measurement of the electromagnet force loads on the hybrid rotor in a novel bearingless switched-reluctance motor (BSRM) have been performed. A BSRM has the combined characteristics of a switched-reluctance motor and a magnetic bearing. The BSRM has an eight-pole stator and a six-pole hybrid rotor, which is composed of circular and scalloped lamination segments. The hybrid rotor is levitated using only one set of stator poles. A second set of stator poles imparts torque to the scalloped portion of the rotor, which is driven in a traditional switched reluctance manner by a processor. Analysis was done for nonrotating rotor poles that were oriented to achieve maximum and minimum radial force loads on the rotor. The objective is to assess whether simple one-dimensional magnetic circuit analysis is sufficient for preliminary evaluation of this machine, which may exhibit strong three-dimensional electromagnetic field behavior. Two magnetic circuit geometries, approximating the complex topology of the magnetic fields in and around the hybrid rotor, were employed in formulating the electromagnetic radial force equations. Reasonable agreement between the experimental results and the theoretical predictions was obtained with typical magnetic bearing derating factors applied to the predictions.

Morrison, Carlos R.; Siebert, Mark W.; Ho, Eric J.

2007-01-01

192

Revisiting the two first instabilities of the flow in an annular rotor-stator cavity  

NASA Astrophysics Data System (ADS)

The stability of the flow enclosed between a stationary and a rotating disk with a central hub is revisited by experimental visualizations and direct numerical simulations in the case of unmerged boundary layers. The first instability appears as circular rolls, denoted by CRs (type 2 instability), which propagate along the stator before vanishing in the vicinity of the hub. The calculations highlight the convective nature of these rolls, which is in agreement with previous experimental results (P. Gauthier, P. Gondret, and M. Rabaud, J. Fluid Mech. 386, 105 (1999)). It proves in particular that the CR instability observed in the experiment under permanent conditions is noise sustained. Above a second threshold, spiral rolls, denoted SR1 (type 1 instability), appear at the periphery of the cavity and can coexist with the circular rolls. The DNS shows that they appear through a supercritical Hopf bifurcation. The SR1 patterns appear to be very close to those emitted by the corner vortices obtained by Lopez and Weidman [J. Fluid Mech. 326, 373 (1996)] during the spin-down of a rotating disk in a fixed cylinder.

Poncet, Sébastien; Serre, Éric; Le Gal, Patrice

2009-06-01

193

A new facility to study three dimensional viscous flow and rotor-stator interaction in turbines  

NASA Technical Reports Server (NTRS)

A description of the Axial Flow Turbine Research Facility (AFTRF) being built at the Turbomachinery Laboratory of the Pennsylvania State University is presented. The purpose of the research to be performed in this facility is to obtain a better understanding of the rotor/stator interaction, three dimensional viscous flow field in nozzle and rotor blade passages, spanwise mixing and losses in these blade rows, transport of wake through rotor passage, and unsteady aerodynamics and heat transfer of rotor blade row. The experimental results will directly feed and support the analytical and the computational tool development. This large scale low speed facility is heavily instrumented with pressure and temperature probes and has provision for flow visualization and laser Doppler anemometer measurement. The facility design permits extensive use of the high frequency response instrumentation on the stationary vanes and more importantly on the rotating blades. Furthermore it facilitates detailed nozzle wake, rotor wake, and boundary layer surveys. The large size of the rig also has the advantage of operating at Reynolds numbers representative of the engine environment.

Lakshminarayana, B.; Camci, C.; Halliwell, I.

1989-01-01

194

Detached eddy simulation of the rotor-stator interaction phenomenon in a moving cascade of airfoils  

NASA Astrophysics Data System (ADS)

Flow inside turbomachinery is fairly complex in general, due to the geometry complexity and the intrinsic structure of the flow. Rotor-Stator Interaction (RSI) has a strong influence on the machine behavior, especially when the machine is operating in off-design conditions, where flow complexity increases due to the presence of boundary layer detachment influencing the general flow pattern and creating pressure pulses that can enhance the RSI behavior. These interactions can have a significant impact on the vibrational and acoustical characteristics of the machine. For gaining insight in the RSI characteristics and the behavior of a turbomachinery under this kind of flow interaction, in this work the RSI generated between a moving cascade of airfoils and fixed flat plate located downstream was studied by means of Computational Fluid Dynamics (CFD) using Detached Eddy Simulation (DES). The upstream boundary layer influence on the wake of the moving cascade, and the subsequent wake-boundary layer interaction between the cascade and a fixed flat plate downstream were obtained and compared against experimental and previous numerical results (obtained with Eddy Viscosity Models). Design and off-design conditions were modeled and a detailed comparison between them has been made. To analyze in detail the flow pattern, mean and fluctuating velocities were obtained and compared against experimental results. Furthermore, results concerning to turbulence intensity were compared against an experimental database.

Guardo, A.; Fontanals, A.; Coussirat, M.; Egusquiza, E.

2012-11-01

195

Current-based sensorless detection of stator winding turn faults in induction machines  

NASA Astrophysics Data System (ADS)

To improve the reliability of motor-driven processes, condition monitoring of electric machines has received considerable attention from industry. For small- and medium-sized machines, the focus is on low-cost sensorless schemes that use only measured voltages and currents for fault diagnostics. Turn faults arising from stator winding insulation deterioration account for a large percentage of motor failures. The objective of a turn-fault detection scheme is to provide a warning before the fault propagates further and results in ground current, causing irreversible damage to the magnetic material. In this work, a neural-network-based robust scheme for early detection of turn faults in induction machines is developed. The negative-sequence component of line currents is used as the fault signature, and a neural network is trained to compensate for the effects of unbalanced supply voltages and nonidealities in the machine or instrumentation. Novel training algorithms for self-commissioning and on-line training of the neural network have also been developed. Experimental results, obtained on a specially-rewound machine, are provided to demonstrate that the method is capable of early fault detection. Data memory and computational requirements are also minimal, making the scheme viable for commercial implementation. The method is also extended to turn-fault detection in open-loop inverter-fed induction machines. Data obtained from a thermally accelerated insulation failure experiment is also used to test the performance and sensitivity of the method, and to show that a turn fault can be detected before failure of insulation to ground.

Tallam, Rangarajan M.

196

Application of the non-linear harmonic method to study the rotor-stator interaction in Francis-99 test case  

NASA Astrophysics Data System (ADS)

Steady state and non-linear harmonic (NLH) flow simulations were performed within the framework of the Francis-99 project in order to assess the capacity of the NLH method to capture the main pressure fluctuations associated with the rotor-stator interactions between the distributor and the runner of the turbine. This paper focusses on the methodology developed to obtain harmonic solutions and presents preliminary results from the simulations using the flow solver NUMECA FineTURBO on intermediate grid level meshes. Comparisons of the first simulations to experimental data reveal good agreement concerning the predicted pressure amplitudes notably at high load operating condition.

Buron, J. D.; Houde, S.; Lestriez, R.; Deschênes, C.

2015-01-01

197

Stalled and stall-free performance of axial-flow compressor stage with three inlet-guide-vane and stator-blade settings  

NASA Technical Reports Server (NTRS)

The performance of the first stage of a transonic, multistage compressor was mapped over a range of inlet-guide-vane and stator-blade settings. Both stall-free and deep-stall performance data were obtained. For the settings tested, as stall was encountered and flow was further reduced, a relatively sharp drop in pressure ratio occurred and was followed by a continuing but more gradual reduction in pressure ratio with reduced flow. The position of the stall line on the map of pressure ratio against equivalent weight flow was essentially unaffected over the range of inlet-guide-vane and stator-blade settings.

Urasek, D. C.; Steinke, R. J.; Cunnan, W. S.

1977-01-01

198

Studying the development of asynchronous rolling of the rotor over the stator with the turbine unit protection systems having different response times  

NASA Astrophysics Data System (ADS)

The possibility to stabilize the developing asynchronous rolling of the rotor over the stator under the conditions of power unit protections coming in action with different response times is considered. Asynchronous rolling of the rotor over the stator may develop when the rotating rotor comes in contact with the stator at high amplitudes of vibration caused by an abrupt loss of rotor balancing, by forced or self-excited vibration of the rotor, and by other factors. The danger of asynchronous rolling is connected with almost instantaneous development of self-excited vibration of the rotor when it comes in contact with the stator and with the rotor vibration amplitudes and forces of interaction between the rotor and stator dangerous for the turbine unit integrity. It is assumed that the turbine unit protection systems come in action after the arrival of signal of exceeding the permissible vibration level and produce commands to disconnect the generator from the grid, and to stop the supply of working fluid into the flow path, due to which an accelerating torque ceases to act on the turbine unit shaft. The protection system response speed is determined by a certain time t = ABtime that is taken for its components to come in action from the commencement of the event (application of the signal) to closure of the stop valves. The time curves of the main rolling parameters as functions of the ABtime value are presented. It is shown that the response time of existing protection systems is not sufficient for efficiently damping the rolling phenomenon, although the use of an electrical protection system (with the response time equal to 0.40-0.45 s) may have a positive effect on stabilizing the vibration amplitudes to a certain extent during the rolling and on smoothing its dangerous consequences. The consequences of rotor rolling over the stator can be efficiently mitigated by increasing the energy losses in the rotor-stator system (especially in the stator) and by fulfilling the recommendations of the machinery unit catastrophe prevention system.

Shatokhin, V. F.

2014-07-01

199

Understanding the apparent stator-rotor connections in the rotary ATPase family using coarse-grained computer modeling.  

PubMed

Advances in structural biology, such as cryo-electron microscopy (cryo-EM) have allowed for a number of sophisticated protein complexes to be characterized. However, often only a static snapshot of a protein complex is visualized despite the fact that conformational change is frequently inherent to biological function, as is the case for molecular motors. Computer simulations provide valuable insights into the different conformations available to a particular system that are not accessible using conventional structural techniques. For larger proteins and protein complexes, where a fully atomistic description would be computationally prohibitive, coarse-grained simulation techniques such as Elastic Network Modeling (ENM) are often employed, whereby each atom or group of atoms is linked by a set of springs whose properties can be customized according to the system of interest. Here we compare ENM with a recently proposed continuum model known as Fluctuating Finite Element Analysis (FFEA), which represents the biomolecule as a viscoelastic solid subject to thermal fluctuations. These two complementary computational techniques are used to answer a critical question in the rotary ATPase family; implicit within these motors is the need for a rotor axle and proton pump to rotate freely of the motor domain and stator structures. However, current single particle cryo-EM reconstructions have shown an apparent connection between the stators and rotor axle or pump region, hindering rotation. Both modeling approaches show a possible role for this connection and how it would significantly constrain the mobility of the rotary ATPase family. PMID:25174610

Richardson, Robin A; Papachristos, Konstantinos; Read, Daniel J; Harlen, Oliver G; Harrison, Michael; Paci, Emanuele; Muench, Stephen P; Harris, Sarah A

2014-12-01

200

Broadband Noise of Fans - With Unsteady Coupling Theory to Account for Rotor and Stator Reflection/Transmission Effects  

NASA Technical Reports Server (NTRS)

This report examines the effects on broadband noise generation of unsteady coupling between a rotor and stator in the fan stage of a turbofan engine. Whereas previous acoustic analyses treated the blade rows as isolated cascades, the present work accounts for reflection and transmission effects at both blade rows by tracking the mode and frequency scattering of pressure and vortical waves. The fan stage is modeled in rectilinear geometry to take advantage of a previously existing unsteady cascade theory for 3D perturbation waves and thereby use a realistic 3D turbulence spectrum. In the analysis, it was found that the set of participating modes divides itself naturally into "independent mode subsets" that couple only among themselves and not to the other such subsets. This principle is the basis for the analysis and considerably reduces computational effort. It also provides a simple, accurate scheme for modal averaging for further efficiency. Computed results for a coupled fan stage are compared with calculations for isolated blade rows. It is found that coupling increases downstream noise by 2 to 4 dB. Upstream noise is lower for isolated cascades and is further reduced by including coupling effects. In comparison with test data, the increase in the upstream/downstream differential indicates that broadband noise from turbulent inflow at the stator dominates downstream noise but is not a significant contributor to upstream noise.

Hanson, Donald B.

2001-01-01

201

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  

NASA Technical Reports Server (NTRS)

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 in terms of equivalent mass flow, torque, power, and efficiency for stator-vane-chord setting angles of 26 degs, 30 degs, 35 degs (design), 40 degs, 45 degs, and 50 degs. Turbine braking performance at a nominal stator setting angle of 107 degs is also presented. Turbine efficiency increased with increasing stator setting angle. A 10-point efficiency increase was obtained by opening the stator from the design setting angle of 35 degs to a setting angle of 45 degs.

Mclallin, K. L.; Kofskey, M. G.

1979-01-01

202

Reliability and Confidence Interval Analysis of a CMC Turbine Stator Vane  

NASA Technical Reports Server (NTRS)

High temperature ceramic matrix composites (CMC) are being explored as viable candidate materials for hot section gas turbine components. These advanced composites can potentially lead to reduced weight, enable higher operating temperatures requiring less cooling and thus leading to increased engine efficiencies. However, these materials are brittle and show degradation with time at high operating temperatures due to creep as well as cyclic mechanical and thermal loads. In addition, these materials are heterogeneous in their make-up and various factors affect their properties in a specific design environment. Most of these advanced composites involve two- and three-dimensional fiber architectures and require a complex multi-step high temperature processing. Since there are uncertainties associated with each of these in addition to the variability in the constituent material properties, the observed behavior of composite materials exhibits scatter. Traditional material failure analyses employing a deterministic approach, where failure is assumed to occur when some allowable stress level or equivalent stress is exceeded, are not adequate for brittle material component design. Such phenomenological failure theories are reasonably successful when applied to ductile materials such as metals. Analysis of failure in structural components is governed by the observed scatter in strength, stiffness and loading conditions. In such situations, statistical design approaches must be used. Accounting for these phenomena requires a change in philosophy on the design engineer s part that leads to a reduced focus on the use of safety factors in favor of reliability analyses. The reliability approach demands that the design engineer must tolerate a finite risk of unacceptable performance. This risk of unacceptable performance is identified as a component's probability of failure (or alternatively, component reliability). The primary concern of the engineer is minimizing this risk in an economical manner. The methods to accurately determine the service life of an engine component with associated variability have become increasingly difficult. This results, in part, from the complex missions which are now routinely considered during the design process. These missions include large variations of multi-axial stresses and temperatures experienced by critical engine parts. There is a need for a convenient design tool that can accommodate various loading conditions induced by engine operating environments, and material data with their associated uncertainties to estimate the minimum predicted life of a structural component. A probabilistic composite micromechanics technique in combination with woven composite micromechanics, structural analysis and Fast Probability Integration (FPI) techniques has been used to evaluate the maximum stress and its probabilistic distribution in a CMC turbine stator vane. Furthermore, input variables causing scatter are identified and ranked based upon their sensitivity magnitude. Since the measured data for the ceramic matrix composite properties is very limited, obtaining a probabilistic distribution with their corresponding parameters is difficult. In case of limited data, confidence bounds are essential to quantify the uncertainty associated with the distribution. Usually 90 and 95% confidence intervals are computed for material properties. Failure properties are then computed with the confidence bounds. Best estimates and the confidence bounds on the best estimate of the cumulative probability function for R-S (strength - stress) are plotted. The methodologies and the results from these analyses will be discussed in the presentation.

Murthy, Pappu L. N.; Gyekenyesi, John P.; Mital, Subodh K.

2008-01-01

203

Turbine blade platform film cooling with simulated stator-rotor purge flow with varied seal width and upstream wake with vortex  

E-print Network

The turbine blade platform can be protected from hot mainstream gases by injecting cooler air through the gap between stator and rotor. The effectiveness of this film cooling method depends on the geometry of the slot, the quantity of injected air...

Blake, Sarah Anne

2009-05-15

204

Analysis of a novel stator winding structure minimizing harmonic current and torque ripple for dual six-step converter-fed high power AC machines  

Microsoft Academic Search

The authors study the causes of degraded converter current when dual six-step power converters feed a dual winding induction machine drive. They proposed an end winding structure and corresponding control strategy to solve the converter current problem while retaining the advantages of the dual winding induction machine drive. Principles associated with the stator winding are discussed, and a practical implementation

Lurong Ye; Longya Xu

1993-01-01

205

Representation of iron core and dielectric losses for calculation of common mode stator ground currents in inverter-fed AC machines  

Microsoft Academic Search

A time-domain high frequency model of an induction machine, which is based on the design parameters, is proposed for calculation of common mode (CM) stator ground currents in inverter-fed AC machines. Basically, the model is an extension of the measured frequency response models and considers an adequate representation of the iron core and dielectric losses over a wide frequency range,

Oliver Magdun; Andreas Binder; Yves Gemeinder

2010-01-01

206

Unsteady Flows in a Single-Stage Transonic Axial-Flow Fan Stator Row. Ph.D. Thesis - Iowa State Univ.  

NASA Technical Reports Server (NTRS)

Measurements of the unsteady velocity field within the stator row of a transonic axial-flow fan were acquired using a laser anemometer. Measurements 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 which are 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 D.

1986-01-01

207

The effects of inlet turbulence and rotor\\/stator interactions on the aerodynamics and heat transfer of a large-scale rotating turbine model, volume 1  

Microsoft Academic Search

A combined experimental and analytical program was conducted to examine the effects of inlet turbulence on airfoil heat transfer. Heat transfer measurements were obtained using low conductivity airfoils with miniature thermocouples welded to a thin, electrically heated surface skin. Heat transfer data were acquired for various combinations of low or high inlet turbulence intensity, flow coefficient (incidence), first-stator\\/rotor axial spacing,

R. P. Dring; M. F. Blair; H. D. Joslyn; G. D. Power; J. M. Verdon

1987-01-01

208

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

209

Performance improvements of a subsonic axial-flow compressor by means of a non-axisymmetric stator hub end-wall  

NASA Astrophysics Data System (ADS)

This paper deals with the application of a non-axisymmetric hub end-wall on the stator of a single stage high subsonic axial-flow compressor. In order to obtain a state-of-the-art stator non-axisymmetric hub end-wall configuration fulfilling the requirements for higher efficiency and total pressure ratio, an automated multi-objective optimizer was used, in conjunction with 3D-RANS-flow simulations. For the purpose of quantifying the effect of the optimal stator non axis-symmetric hub contouring on the compressor performance and its effects on the subsonic axial-flow compressor stator end-wall flow field structure, the coupled flow of the compressor stage with the baseline, axisymmetric and the non-axisymmetric stator hub end-wall was simulated with a state-of-theart multi-block flow 3D CFD solver. Based on the CFD simulations, the optimal compressor hub end-wall configuration is expected to increase the peak efficiency by approximately 2.04 points and a slight increase of the total pressure ratio. Detailed analyses of the numerical flow visualization at the hub have uncovered the different hub flow topologies between the cases with axisymmetric and non-axisymmetric hub end-walls. It was found that that the primary performance enhancement afforded by the non-axisymmetric hub end-wall is a result of the end-wall flow structure modification. Compared to the smooth wall case, the non-axisymmetric hub end-wall can reduce the formation and development of in-passage secondary flow by aerodynamic loading redistribution.

Zhang, Xuefeng; Lu, Xingen; Zhu, Junqiang

2013-12-01

210

Characterization of the Periplasmic Domain of MotB and Implications for Its Role in the Stator Assembly of the Bacterial Flagellar Motor?  

PubMed Central

MotA and MotB are integral membrane proteins that form the stator complex of the proton-driven bacterial flagellar motor. The stator complex functions as a proton channel and couples proton flow with torque generation. The stator must be anchored to an appropriate place on the motor, and this is believed to occur through a putative peptidoglycan-binding (PGB) motif within the C-terminal periplasmic domain of MotB. In this study, we constructed and characterized an N-terminally truncated variant of Salmonella enterica serovar Typhimurium MotB consisting of residues 78 through 309 (MotBC). MotBC significantly inhibited the motility of wild-type cells when exported into the periplasm. Some point mutations in the PGB motif enhanced the motility inhibition, while an in-frame deletion variant, MotBC(?197-210), showed a significantly reduced inhibitory effect. Wild-type MotBC and its point mutant variants formed a stable homodimer, while the deletion variant was monomeric. A small amount of MotB was coisolated only with the secreted form of MotBC-His6 by Ni-nitrilotriacetic acid affinity chromatography, suggesting that the motility inhibition results from MotB-MotBC heterodimer formation in the periplasm. However, the monomeric mutant variant MotBC(?197-210) did not bind to MotB, suggesting that MotBC is directly involved in stator assembly. We propose that the MotBC dimer domain plays an important role in targeting and stable anchoring of the MotA/MotB complex to putative stator-binding sites of the motor. PMID:18310339

Kojima, Seiji; Furukawa, Yukio; Matsunami, Hideyuki; Minamino, Tohru; Namba, Keiichi

2008-01-01

211

Streakline flow visualization study of a horseshoe vortex in a large-scale, two-dimensional turbine stator cascade  

NASA Technical Reports Server (NTRS)

Neutrally bouyant helium-filled bubbles were observed as they followed the streamlines in a horseshoe vortex system around the vane leading edge in a large scale, two dimensional, turbine stator cascade. Inlet Reynolds number, based on true chord, ranged between 100,000 to 300,000. Bubbles were introduced into the endwall boundary layer through a slot upstream of the vane leading edge. The paths of the bubbles were recorded photographically as streaklines on 16 mm movie film. Individual frames from the film were selected, and overlayed to show the details of the horseshoe vortex around the leading edge. The transport of the vortex across the passage near the leading edge is clearly seen when compared to the streaks formed by bubbles carried in the main stream. Limiting streamlines on the endwall surface were traced by the flow of oil drops.

Gaugler, R. E.; Russell, L. M.

1979-01-01

212

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

213

Theory for broadband Noise of Rotor and Stator Cascades with Inhomogeneous Inflow Turbulence Including Effects of Lean and Sweep  

NASA Technical Reports Server (NTRS)

The problem of broadband noise generated by turbulence impinging on a downstream blade row is examined from a theoretical viewpoint. Equations are derived for sound power spectra in terms of 3 dimensional wavenumber spectra of the turbulence. Particular attention is given to issues of turbulence inhomogeneity associated with the near field of the rotor and variations through boundary layers. Lean and sweep of the rotor or stator cascade are also handled rigorously with a full derivation of the relevant geometry and definitions of lean and sweep angles. Use of the general theory is illustrated by 2 simple theoretical spectra for homogeneous turbulence. Limited comparisons are made with data from model fans designed by Pratt & Whitney, Allison, and Boeing. Parametric studies for stator noise are presented showing trends with Mach number, vane count, turbulence scale and intensity, lean, and sweep. Two conventions are presented to define lean and sweep. In the "cascade system" lean is a rotation out of its plane and sweep is a rotation of the airfoil in its plane. In the "duct system" lean is the leading edge angle viewing the fan from the front (along the fan axis) and sweep is the angle viewing the fan from the side (,perpendicular to the axis). It is shown that the governing parameter is sweep in the plane of the airfoil (which reduces the chordwise component of Mach number). Lean (out of the plane of the airfoil) has little effect. Rotor noise predictions are compared with duct turbulence/rotor interaction noise data from Boeing and variations, including blade tip sweep and turbulence axial and transverse scales are explored.

Hanson, Donald B.

2001-01-01

214

Aerodynamic performances of three fan stator designs operating with rotor having tip speed of 337 meters per second and pressure ratio of 1.54. Relation of analytical code calculations to experimental performance  

NASA Technical Reports Server (NTRS)

A hub-to-shroud and a blade-to-blade internal-flow analysis code, both inviscid and basically subsonic, were used to calculate the flow parameters within four stator-blade rows. The produced ratios of maximum suction-surface velocity to trailing-edge velocity correlated well in the midspan region, with the measured total-parameters over the minimum-loss to near stall operating range for all stators and speeds studied. The potential benefits of a blade designed with the aid of these flow analysis codes are illustrated by a proposed redesign of one of the four stators studied. An overall efficiency improvement of 1.6 points above the peak measured for that stator is predicted for the redesign.

Gelder, T. F.; Schmidt, J. F.; Esgar, G. M.

1980-01-01

215

Single-stage experimental evaluation of tandem-airfoil rotor and stator blading for compressors. Part 3: Data and performance for stage C  

NASA Technical Reports Server (NTRS)

Stage C, comprised of tandem-airfoil rotor C and tandem-airfoil stator B, was designed and tested to establish performance data for comparison with the performance of conventional single-airfoil blading. Velocity diagrams and blade leading and trailing edge metal angles selected for the conventional rotor and stator blading were used in the design of the tandem blading. The rotor had an inlet hub/tip ratio of 0.8 and a design tip velocity of 757 ft/sec. At design equivalent rotor speed, rotor C achieved a maximum adiabatic efficiency of 91.8% at a pressure ratio of 1.31. The stage maximum adiabatic efficiency was 86.5% at a pressure ratio of 1.31.

Brent, J. A.; Clemmons, D.

1972-01-01

216

Effect of rotor-to-stator spacing on acoustic performance of a full-scale fan (QF-5) for turbofan engines  

NASA Technical Reports Server (NTRS)

A study was made of the effect of increasing the fan rotor-to-stator spacing on the noise level of a full-scale, single-stage, 1.6-pressure-ratio fan. Noise data were obtained with axial spacing of 1.14, 1.65, and 2.27 rotor chord lengths. Over this spacing range, data indicate a reduction of 1.5 PNdb. Apparently, rotor-alone noise at the frequency at which the rotor-stator interaction noise was cut off limited the noise reduction for the QF-5 fan. It seems, however, that the reduction in sound power level with increases in spacing is potentially about 6 db over the range of spacing tested.

Balombin, J. R.; Stakolich, E. G.

1974-01-01

217

Two-dimensional analytical and experimental performance comparison for a compressor stator section with D-factor of 0.47  

NASA Technical Reports Server (NTRS)

Analytically computed flow parameters were compared to measured values for the midspan double-circular-arc section of a stator in subsonic flow. Analytical procedures included calculations for inviscid flow, blade surface boundary layers, and loss coefficients. Comparisons were made at three incidence angles. Methods for prescribing the exit fluid angle in inviscid flow calculations were investigated. Measured loss coefficients were compared to calculated values. Two methods for predicting performance involving iterative use of ideal flow and boundary layer calculations were investigated.

Sanger, N. L.

1973-01-01

218

Novel method for detecting interlamination short-circuits in a stator core based on measurement of eddy-current losses in power generators  

NASA Astrophysics Data System (ADS)

A novel method based on the measurement of eddy-current losses for detecting short-circuits in laminated stator cores in power generators is presented. The basic theoretical principle and its comparison with current methods are reviewed. The proposed technique set-up and the mathematical data processing are shown. Finally, the new technique is tested both in the laboratory and the field. The results of the application are shown and discussed.

Ramírez-Niño, J.; Pascacio S, A.

2003-12-01

219

Cold-air performance of free power turbine designed for 112-kilowatt automotive gas-turbine engine 3: Effect of stator vane end clearances on performance  

NASA Technical Reports Server (NTRS)

An experimental investigation of a free power turbine designed for a 112-kW, automotive, gas turbine engine was made to determine the penalty in performance due to the stator vane end clearances. Tests were made over a range of mean section stator vane angles from 26 deg to 50 deg (as measured from the plane of rotation) with the vane end clearances filled. These results were compared with test results of the same turbine with vane end clearances open. At design equivalent values of rotative speed and pressure ratio and at a vane angle of 35 deg, the mass flow with the vane and clearances filled was about 8 percent lower than mass flow with vane end clearances open. The decrease in mass flow was mitigated by increasing the vane angle. With the vane end clearances filled, there was about a 66 percent reduction in mass flow when the vane angle was decreased from 40 deg to 26 deg. For the same decrease in vane angle the stator throat area decreased by about 50 percent. This result indicates that the rotor losses were increasing with decreasing vane angle.

Kofskey, M. G.; Mclallin, K. L.

1978-01-01

220

Development and testing of a 2.5 kW synchronous generator with a high temperature superconducting stator and permanent magnet rotor  

NASA Astrophysics Data System (ADS)

High temperature superconducting (HTS) armature windings have the potential for increasing the electric loading of a synchronous generator due to their high current transport capacity, which could increase the power density of an HTS rotating machine. In this work, a novel synchronous generator prototype with an HTS stator and permanent magnet rotor has been developed. It has a basic structure of four poles and six slots. The armature winding was constructed from six double-pancake race-track coils with 44 turns each. It was designed to deliver 2.5 kW at 300 rpm. A concentrated winding configuration was proposed, to prevent interference at the ends of adjacent HTS coils. The HTS stator was pressure mounted into a hollow Dewar cooled with liquid nitrogen. The whole stator could be cooled down to around 82 K by conduction cooling. In the preliminary testing, the machine worked properly and could deliver 1.8 kW power when the armature current was 14.4 A. Ic for the HTS coils was found to be suppressed due to the influence of the temperature and the leakage field.

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

2014-04-01

221

High-loading low-speed fan study. 4: Data and performance with redesign stator and including a rotor tip casing treatment  

NASA Technical Reports Server (NTRS)

A single stage fan with a rotor tip speed of 1000 ft/sec(304.8 m/sec) and a hub-to-tip ratio of 0.392 was retested with a redesigned stator. Tests were conducted with uniform inlet, tip-radial, hub-radial, and circumferential inlet distortions. With uniform inlet flow, stall margin was improved 12 percentage points above that with the original stator. The fan demonstrated an efficiency of 0.883 and a stall margin of 15 percent at a pressure ratio of 1.488 and a specific flow of 41.17 lb/sec/sq ft. Tests were also made with a redesigned casing treatment consisting of skewed slots over the rotor blade tips. This casing treatment gave a 7 percentage point improvement in stall margin when tested with tip radial distortion (when the rotor tip initiated stall). Noise measurements at the fan inlet and exit indicate no effect from closing the stator 10 degrees, nor were there measurable effects from adding skewed slots over the blade tips.

Harley, K. G.; Odegard, P. A.; Burdsall, E. A.

1972-01-01

222

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. PMID:21723829

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

2011-01-01

223

Solid-state molecular rotors with perdeuterated stators: mechanistic insights from biphenylene rotational dynamics in ordered and disordered crystal forms.  

PubMed

Samples of 4,4'-bis(3,3,3-tri-d(5)-phenylpropynyl)biphenyl 2, 9,10-bis(3,3,3-tri-d(5)-phenylpropynyl)anthracene 3, 1,4-bis(3,3,3-tri-d(5)-phenylpropynyl)naphthalene 4, and 4,4'-bis(3,3,3-tri-d(5)-phenylpropynyl)-1,1'-binaphthyl 5 were prepared via a Sonogashira coupling of 3,3,3-tri-d(5)-phenylpropyne 7 and the appropriate aryl dibromide. Single crystal X-ray diffraction structures were obtained for an o-xylene clathrate of 2 and for solvent-free crystals of 3. All four molecular rotors were characterized by CPMAS (13)C NMR experiments with varying contact times in order to determine whether the carbon signals of the central rotator group could be selectively enhanced and studied without interference or overlap of signals from the deuterated stator, which is insensitive to the {(1)H}-(13)C cross-polarization method. It was shown that the (13)C signals of the natural abundance rotator group can be selectively observed with short contact times (ca. 50 micros) without interference from other (13)C signals in the molecule. Variable-temperature CPMAS (13)C NMR studies with a crystalline o-xylene solvate of biphenylene rotor 2 suggested a 2-fold flipping process in the fast exchange regime, even at temperatures as low as 199 K (-74 degrees C). Indirect support for this was obtained by studies carried out with a disordered, solvent-free solid, obtained by fast precipitation from hexanes and dichloromethane, which displayed slower dynamics within the same temperature range with an activation energy of 8.7 kcal/mol and a pre-exponential factor of 4.9 x 10(9) s(-1). Confirmation of an exchange process in the megahertz regime for the crystalline solvate was obtained by variable-temperature quadrupolar echo (2)H NMR data acquired with samples prepared with a deuterated biphenylene rotator and a natural abundance stator. Although rotational exchange occurs in the solvated samples with a slightly lower barrier of 7.4 kcal/mol, the main difference with the precipitated solid comes from the pre-exponential factor, which is nearly 3 orders of magnitude greater with a value of 2.5 x 10(12) s(-1). On the basis of these differences, we speculate that efficient rotational motion in the solvated crystals may take advantage of long-range lattice vibrations that couple with molecular modes and that the lack of long-range order may be responsible for the low pre-exponential factor observed in the disordered crystals. PMID:20232842

O'Brien, Zachary J; Karlen, Steven D; Khan, Saeed; Garcia-Garibay, Miguel A

2010-04-16

224

Tribenzotriquinacene receptors for C60 ?fullerene rotors: towards C3 symmetrical chiral stators for unidirectionally operating nanoratchets.  

PubMed

The synthesis of a stereochemically pure concave tribenzotriquinacene receptor (7) for C60 fullerene, possessing C3 point group symmetry, by threefold condensation of C2 -symmetric 1,2-diketone synthons (5) and a hexaaminotribenzotriquinacene core (6) is described. The chiral diketone was synthesized in a five-step reaction sequence starting from C2h -symmetric 2,6-di-tert-butylanthracene. The highly diastereo-discriminating Diels-Alder reaction of 2,6-di-tert-butylanthracene with fumaric acid di(-)menthyl ester, catalyzed by aluminium chloride, is the relevant stereochemistry introducing step. The structure of the fullerene receptor was verified by (1)H and (13)C?NMR spectroscopy, mass spectrometry and single crystal X-ray diffraction. VCD and ECD spectra were recorded, which were corroborated by ab initio DFT calculations, establishing the chiral nature of 7 with about 99.7?% ee, based on the ee (99.9?%) of the chiral synthon (1). The absolute configuration of 7 could thus be established as all-S [(2S,7S,16S,21S,30S,35S)-(7)]. Spectroscopic titration experiments reveal that the host forms 1:1 complexes with either pure fullerene (C60) or fullerene derivatives, such as rotor 1'-(4-nitrophenyl)-3'-(4-N,N-dimethylaminophenyl)-pyrazolino[4',5':1,2][60]fullerene (R). The complex stability constants of the complexes dissolved in CHCl3/CS2 (1:1 vol.?%) are K([C60 ?7]) = 319(±156)?M(-1) and K([R?7]) = 110(±50)?M(-1). With molecular dynamics simulations using a first-principles parameterized force field the asymmetry of the rotational potential for [R?7] was shown, demonstrating the potential suitability of receptor 7 to act as a stator in a unidirectionally operating nanoratchet. PMID:24965605

Bredenkötter, Björn; Grzywa, Maciej; Alaghemandi, Mohammad; Schmid, Rochus; Herrebout, Wouter; Bultinck, Patrick; Volkmer, Dirk

2014-07-14

225

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

2011-08-01

226

Design and two dimensional cascade test of a jet-flap turbine stator blade with ratio of axial chord to spacing of 0.5  

NASA Technical Reports Server (NTRS)

A jet-flap blade was designed for a velocity diagram typical of the first-stage stator of a jet engine turbine and was tested in a simple two-dimensional cascade of six blades. The principal measurements were blade surface static pressure and cross-channel surveys of exit total pressure, static pressure, and flow angle. The results of the experimental investigation include blade loading, exit angle, flow, and loss data for a range of exit critical velocity ratios and three jet flow conditions.

Stabe, R. G.

1971-01-01

227

Two-dimensional cold-air cascade study of a film-cooled turbine stator blade. 3: Effect of hole size on single-row and multirow ejection  

NASA Technical Reports Server (NTRS)

The effect of coolant discharge on the aerodynamic performance of a film cooled turbine stator blade was determined. The blade had the same number, location, and injection angle of coolant holes, but the coolant hole diameters were one half that of a previously investigated blade. Otherwise the blades were the same. Tests with discharge from individual coolant rows and multiple coolant rows, including full film discharge are studied. The results of the blade with smaller holes are reported and compared with the blades with larger holes.

Prust, H. W., Jr.; Moffitt, T. P.

1976-01-01

228

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

229

Contribution of many charged residues at the stator-rotor interface of the Na+-driven flagellar motor to torque generation in Vibrio alginolyticus.  

PubMed

In torque generation by the bacterial flagellar motor, it has been suggested that electrostatic interactions between charged residues of MotA and FliG at the rotor-stator interface are important. However, the actual role(s) of those charged residues has not yet been clarified. In this study, we systematically made mutants of Vibrio alginolyticus whose charged residues of PomA (MotA homologue) and FliG were replaced by uncharged or charge-reversed residues and characterized the motilities of those mutants. We found that the members of a group of charged residues, 7 in PomA and 6 in FliG, collectively participate in torque generation of the Na(+)-driven flagellar motor in Vibrio. An additional specific interaction between PomA-E97 and FliG-K284 is critical for proper performance of the Vibrio motor. Our results also reveal that more charged residues are involved in the PomA-FliG interactions in the Vibrio Na(+)-driven motor than in the MotA-FliG interactions in the H(+)-driven one. This suggests that a larger number of conserved charged residues at the PomA-FliG interface contributes to the robustness of the Vibrio motor against mutations. The interaction surfaces of the stator and rotor of the Na(+)-driven motor seem to be more complex than those previously proposed in the H(+)-driven motor. PMID:24464458

Takekawa, Norihiro; Kojima, Seiji; Homma, Michio

2014-04-01

230

Contribution of Many Charged Residues at the Stator-Rotor Interface of the Na+-Driven Flagellar Motor to Torque Generation in Vibrio alginolyticus  

PubMed Central

In torque generation by the bacterial flagellar motor, it has been suggested that electrostatic interactions between charged residues of MotA and FliG at the rotor-stator interface are important. However, the actual role(s) of those charged residues has not yet been clarified. In this study, we systematically made mutants of Vibrio alginolyticus whose charged residues of PomA (MotA homologue) and FliG were replaced by uncharged or charge-reversed residues and characterized the motilities of those mutants. We found that the members of a group of charged residues, 7 in PomA and 6 in FliG, collectively participate in torque generation of the Na+-driven flagellar motor in Vibrio. An additional specific interaction between PomA-E97 and FliG-K284 is critical for proper performance of the Vibrio motor. Our results also reveal that more charged residues are involved in the PomA-FliG interactions in the Vibrio Na+-driven motor than in the MotA-FliG interactions in the H+-driven one. This suggests that a larger number of conserved charged residues at the PomA-FliG interface contributes to the robustness of the Vibrio motor against mutations. The interaction surfaces of the stator and rotor of the Na+-driven motor seem to be more complex than those previously proposed in the H+-driven motor. PMID:24464458

Takekawa, Norihiro; Kojima, Seiji

2014-01-01

231

Variable stator radial turbine  

NASA Technical Reports Server (NTRS)

A radial turbine stage with a variable area nozzle was investigated. A high work capacity turbine design with a known high performance base was modified to accept a fixed vane stagger angle moveable sidewall nozzle. The nozzle area was varied by moving the forward and rearward sidewalls. Diffusing and accelerating rotor inlet ramps were evaluated in combinations with hub and shroud rotor exit rings. Performance of contoured sidewalls and the location of the sidewall split line with respect to the rotor inlet was compared to the baseline. Performance and rotor exit survey data are presented for 31 different geometries. Detail survey data at the nozzle exit are given in contour plot format for five configurations. A data base is provided for a variable geometry concept that is a viable alternative to the more common pivoted vane variable geometry radial turbine.

Rogo, C.; Hajek, T.; Chen, A. G.

1984-01-01

232

Two dimensional cold air cascade study of a film cooled turbine stator blade. 2: Experimental results of full film cooling tests  

NASA Technical Reports Server (NTRS)

The effect of full film cooling on the performance of a turbine stator blade was studied in a two-dimensional cascade. The blade contained 12 rows of coolant holes, 6 rows on the suction surface and 6 on the pressure surface. Separate tests were first made with coolant ejection from each of the 12 rows. Then successive tests were made with various combinations of coolant rows open, including full film cooling. The principal results are presented in terms of primary-air efficiency as a function of coolant fraction. In addition, the efficiency results of the multirow tests are compared with the multi-row efficiency predicted by adding the single-row results.

Prust, H. W., Jr.

1975-01-01

233

Windage Power Loss in Gas Foil Bearings and the Rotor-Stator Clearance of High Speed Generators Operating in High Pressure Environments  

NASA Technical Reports Server (NTRS)

Closed Brayton Cycle (CBC) and Closed Supercritical Cycle (CSC) engines are prime candidates to convert heat from a reactor into electric power for robotic space exploration and habitation. These engine concepts incorporate a permanent magnet starter/generator mounted on the engine shaft along with the requisite turbomachinery. Successful completion of the long-duration missions currently anticipated for these engines will require designs that adequately address all losses within the machine. The preliminary thermal management concept for these engine types is to use the cycle working fluid to provide the required cooling. In addition to providing cooling, the working fluid will also serve as the bearing lubricant. Additional requirements, due to the unique application of these microturbines, are zero contamination of the working fluid and entirely maintenance-free operation for many years. Losses in the gas foil bearings and within the rotor-stator gap of the generator become increasingly important as both rotational speed and mean operating pressure are increased. This paper presents the results of an experimental study, which obtained direct torque measurements on gas foil bearings and generator rotor-stator gaps. Test conditions for these measurements included rotational speeds up to 42,000 revolutions per minute, pressures up to 45 atmospheres, and test gases of nitrogen, helium, and carbon dioxide. These conditions provided a maximum test Taylor number of nearly one million. The results show an exponential rise in power loss as mean operating density is increased for both the gas foil bearing and generator windage. These typical "secondary" losses can become larger than the total system output power if conventional design paradigms are followed. A nondimensional analysis is presented to extend the experimental results into the CSC range for the generator windage.

Bruckner, Robert J.

2009-01-01

234

Subunit Positioning and Stator Filament Stiffness in Regulation and Power Transmission in the V1 Motor of the Manduca sexta V-ATPase?  

PubMed Central

The vacuolar H+-ATPase (V-ATPase) is an ATP-driven proton pump essential to the function of eukaryotic cells. Its cytoplasmic V1 domain is an ATPase, normally coupled to membrane-bound proton pump Vo via a rotary mechanism. How these asymmetric motors are coupled remains poorly understood. Low energy status can trigger release of V1 from the membrane and curtail ATP hydrolysis. To investigate the molecular basis for these processes, we have carried out cryo-electron microscopy three-dimensional reconstruction of deactivated V1 from Manduca sexta. In the resulting model, three peripheral stalks that are parts of the mechanical stator of the V-ATPase are clearly resolved as unsupported filaments in the same conformations as in the holoenzyme. They are likely therefore to have inherent stiffness consistent with a role as flexible rods in buffering elastic power transmission between the domains of the V-ATPase. Inactivated V1 adopted a homogeneous resting state with one open active site adjacent to the stator filament normally linked to the H subunit. Although present at 1:1 stoichiometry with V1, both recombinant subunit C reconstituted with V1 and its endogenous subunit H were poorly resolved in three-dimensional reconstructions, suggesting structural heterogeneity in the region at the base of V1 that could indicate positional variability. If the position of H can vary, existing mechanistic models of deactivation in which it binds to and locks the axle of the V-ATPase rotary motor would need to be re-evaluated. PMID:24075871

Muench, Stephen P.; Scheres, Sjors H.W.; Huss, Markus; Phillips, Clair; Vitavska, Olga; Wieczorek, Helmut; Trinick, John; Harrison, Michael A.

2014-01-01

235

Investigation of the Effects of Low Reynolds Number Operation on the Performance of a Single-Stage Turbine with a Downstream Stator  

NASA Technical Reports Server (NTRS)

High-altitude turbojet performance is adversely affected by the effects of low air density. This performance loss is evaluated as a Reynolds number effect, which represents the increased significance of high fluid viscous forces in relation to dynamic fluid forces as the Reynolds number is decreased. An analytical and experimental investigation of the effects of low Reynolds number operation on a single-stage, high-work-output turbine with a downstream stator was carried out at Reynolds numbers of 182,500, 39,600, and 23,000, based on average rotor-design flow conditions. At low Reynolds numbers and turbulent flow conditions, increased viscous losses caused decreased effective flow area, and thus decreased weight flow, torque, and over-all efficiency at a given equivalent speed and pressure ratio. Decreasing the Reynolds number from 182,500 to 23,000 at design equivalent speed resulted in a 5.00-point loss in peak over-all turbine efficiency for both theory and experiment. The choking equivalent weight flow decreased 2.30 percent for these conditions. Limiting loading work output was reached at design equivalent speed for all three Reynolds numbers. The value of limiting loading work output at design speed decreased 4.00 percent as Reynolds number was decreased from 182,500 to 23,000. A theoretical performance-prediction method using basic boundary-layer relations gave good agreement with experimental results over most of the performance range at a given Reynolds number if the experimental and analytical design operating conditions were carefully matched at the highest Reynolds number with regard to design performance parameters. High viscous losses in the inlet stator and rotor prevented the attainment of design equivalent work output at the lowest Reynolds number of 23,000.

Forrette, Robert E.; Holeski, Donald E.; Plohr, Henry W.

1959-01-01

236

Boletín del Instituto Nacional del Cáncer  

Cancer.gov

La edición electrónica del Boletín del Instituto Nacional del Cáncer se publicó mensualmente desde septiembre de 2009 hasta enero de 2013, con el objetivo de difundir información sobre la investigación del cáncer, tanto de estudios financiados por el NCI y otras dependencias federales, así como de investigaciones realizadas por instituciones en Estados Unidos y alrededor del mundo.

237

Análisis descriptivo del tamaño relativo del gasto del gobierno chileno  

Microsoft Academic Search

En este trabajo se examina el tamaño relativo del Gobierno chileno a través de una comparación internacional con valores equivalentes de otros países. Adicionalmente hay un análisis similar para dos componentes importantes del gasto público: educación y salud. El gasto del Gobierno de Chile, valor en torno del 20% (PIB), está junto al tercio inferior de países que poseen un

Eduardo Engel; Patricio Meller; Claudio Bravo

1998-01-01

238

Cold-air performance of a 15.41-cm-tip-diameter axial-flow power turbine with variable-area stator designed for a 75-kW automotive gas turbine engine  

NASA Technical Reports Server (NTRS)

An experimental evaluation of the aerodynamic performance of the axial flow, variable area stator power turbine stage for the Department of Energy upgraded automotive gas turbine engine was conducted in cold air. The interstage transition duct, the variable area stator, the rotor, and the exit diffuser were included in the evaluation of the turbine stage. The measured total blading efficiency was 0.096 less than the design value of 0.85. Large radial gradients in flow conditions were found at the exit of the interstage duct that adversely affected power turbine performance. Although power turbine efficiency was less than design, the turbine operating line corresponding to the steady state road load power curve was within 0.02 of the maximum available stage efficiency at any given speed.

Mclallin, K. L.; Kofskey, M. G.; Wong, R. Y.

1982-01-01

239

Cold-air performance of free-power turbine designed for 112-kilowatt automotive gas-turbine engine. 1: Design Stator-vane-chord setting angle of 35 deg  

NASA Technical Reports Server (NTRS)

A cold air experimental investigation of a free power turbine designed for a 112-kW automotive gas-turbine was made over a range of speeds from 0 to 130 percent of design equivalent speeds and over a range of pressure ratio from 1.11 to 2.45. Results are presented in terms of equivalent power, torque, mass flow, and efficiency for the design power point setting of the variable stator.

Kofskey, M. G.; Nusbaum, W. J.

1978-01-01

240

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

241

Instantánea del cáncer infantil  

Cancer.gov

Información sobre la incidencia y mortalidad del cáncer en los niños, tendencias en el financiamiento del NCI para la investigación del cáncer infantil; así como ejemplos de actividades y adelantos en la investigación relevantes para esta población.

242

Experimental investigation of steady and unsteady flow field downstream of an automotive torque converter turbine and inside the stator. Part 1: Flow at exit of turbine  

SciTech Connect

The objective of this investigation is to understand the steady and the unsteady flow field at the exit of an automotive torque converter turbine and inside the stator with a view toward improving its performance. The measurements were conducted in a stationary frame of reference using a high-frequency response five-hole probe, and the data were processed to derive the flow properties in the relative (turbine) frame of reference. The experimental data were processed in the frequency domain by spectrum analysis and in the temporal-spatial domain by ensemble averaging technique. The flow properties (e.g., pressure and velocity) were resolved into mean, periodic, aperiodic, and unresolved components. A velocity profile similar to that of a fully developed flow was observed at all radii. The periodic data in relative reference frame revealed a small separation zone near the suction surface in the core region. The rms values of the unresolved component were found to be significantly higher in this region. The secondary flow vectors show underturning, radially inward flow in the entire passage with a small region of overturning near the separation zone. The overall flow at the turbine exit was nearly two dimensional in nature except in the zone of flow separation. The unsteady flow data show that unresolved and aperiodic components dominate the unsteadiness in the pressure, whereas the periodic components dominate the unsteadiness in velocities and flow angles. Pressure and velocity fluctuations were moderate, whereas the flow angle fluctuations were found to be high. The overall flow at the exit of turbine was found to be highly unsteady.

Marathe, B.V.; Lakshminarayana, B. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Aerospace Engineering; Maddock, D.G. [General Motors Corp., Ypsilanti, MI (United States). GM Powertrain Group

1997-07-01

243

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

NASA Technical Reports Server (NTRS)

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 of Tennessee Space Institute (UTSI). The objective of the testing at UTSI was to demonstrate that reliable thermal barrier coating (TBC) surface temperatures based on luminescence decay of a thermographic phosphor could be obtained from the surface of an actual engine component in an aggressive afterburner flame environment and to address the challenges of a highly radiant background and high velocity gases. A high-pressure turbine vane doublet from a Honeywell TECH7000 turbine engine was coated with a standard electron-beam physical vapor deposited (EB-PVD) 200-m-thick TBC composed of yttria-stabilized zirconia (YSZ) onto which a 25-m-thick GAP:Cr thermographic phosphor layer was deposited by EB-PVD. The ultra-bright broadband luminescence from the GAP:Cr thermographic phosphor is shown to offer the advantage of over an order-of-magnitude greater emission intensity compared to rare-earth-doped phosphors in the engine test environment. This higher emission intensity was shown to be very desirable for overcoming the necessarily restricted probe light collection solid angle and for achieving high signal-to-background levels. Luminescence-decay-based surface temperature measurements varied from 500 to over 1000C depending on engine operating conditions and level of air film cooling.

Eldridge, Jeffrey I.; Jenkins, Thomas P.; Allison, Stephen W.; Wolfe, Douglas E.; Howard, Robert P.

2013-01-01

244

Atlas del Genoma del Cáncer: Antecedentes  

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.

245

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.

246

Instantánea del cáncer colorrectal  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer colorrectal; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

247

Festival del Sur '98  

E-print Network

andaluz dedicándole una noche temática con dos espectáculos, el de los cubanos Galiano 108 Federico-La Habana-Lorca y el del chileno Franklin Caicedo Lorca y sus amigos poetas; asimismo, se proyectaron varios vídeos sobre su vida y montajes emblemáticos... a veces hacían difícil la comprensión del texto. Todo ello redundó en crear una atmósfera asfixiante y la repulsión del público ante esta lucha entre los sexos y las clases sociales. Desde Bolivia vino Amalilef Teatro con Jamás diré adiós, un...

Má rquez Montes, Carmen

1999-04-01

248

Transformaciones del Estado y del Derecho  

Microsoft Academic Search

El concepto de derecho asentado en la mentalidad jurídica actual responde a un modelo profundamente “estatista”, racional y formal. Sus premisas se construyen de acuerdo con las estructuras y los discursos políticos que se desarrollan durante las postrimerías de la Edad Moderna en Europa y triunfa definitivamente con las revoluciones burguesas. Las formas jurídicas desarrolladas como fundamento y sostén del

Manuel Calvo García

249

TEORÍAS DEL DESARROLLO A PRINCIPIOS DEL SIGLO XXI  

Microsoft Academic Search

1 La evolución de las ideas no sigue el curso de los siglos. Es más, en el transcurso del siglo XX hemos presenciado cambios radicales en lo que a teoría del desarrollo se refiere. Ni siquiera es indispensable definir los siglos de acuerdo con la clasificación del calendario, de cero a noventa y nueve. En su célebre discurso del 8

AMARTYA SEN

250

Hojas informativas del NCI  

Cancer.gov

La colección de hojas informativas del NCI trata de una variedad de temas relacionados con el cáncer. Las hojas informativas se revisan y ponen al día de acuerdo a las investigaciones más recientes sobre el cáncer.

251

en Fisioterapia del Deporte  

E-print Network

Experto en Fisioterapia del Deporte III Edición RESERVA DE PLAZAY MATRÍCULA Título: Experto en Fisioterapia del Deporte Precio de título: 1.800 Plazo de preinscripción: hasta 15 de Octubre 2014 Nº de: TRATAMIENTO DE LA LESI�N DEPORTIVA EN AGUA BLOQUEV: TERAPIAS MANUALES APLICADAS AL DEPORTE BLOQUEVI: PUNCI�N

Rey Juan Carlos, Universidad

252

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).

253

Estudio del CH interestelar  

NASA Astrophysics Data System (ADS)

El objetivo principal de este proyecto consiste en el estudio de la distribución y abundancia del CH en nubes interestelares a través de la observación de las líneas hiperfinas del CH en 3,3 GHz. El CH es una molécula de amplia distribución en el espacio interestelar y una de las pocas especies que han sido observadas tanto con técnicas de radio como ópticas. Desde el punto de vista tecnológico se ha desarrollado un cabezal de receptor que permitirá la realización de observaciones polarimétricas en la frecuencia de 3,3 GHz, con una temperatura del sistema de 60 K y un ancho de banda de 140 MHz, y que será instalado en el foco primario de la antena parabólica del IAR. El cabezal del receptor es capaz de detectar señales polarizadas, separando las componentes de polarización circular derecha e izquierda. Para tal fin el cabezal consta de dos ramas receptoras que amplificarán la señal y la trasladarán a una frecuencia más baja (frecuencia intermedia), permitiendo de esa forma un mejor transporte de la señal a la sala de control para su posterior procesamiento. El receptor además de tener características polarimétricas, podrá ser usado en el continuo y en la línea, utilizando las ventajas observacionales y de procesamiento de señal que actualmente posee el IAR.

Olano, C.; Lemarchand, G.; Sanz, A. J.; Bava, J. A.

254

Instantánea del cáncer de esófago  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de esófago; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

255

Instantánea del cáncer de próstata  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de próstata; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

256

Instantánea del cáncer de vejiga  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de vejiga; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

257

Instantánea del sarcoma de Kaposi  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el sarcoma de Kaposi; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

258

Instantánea del cáncer de pulmón  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de pulmón; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

259

Instantánea del cáncer de endometrio  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de endometrio; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

260

Instantánea del cáncer de páncreas  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de páncreas; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

261

Fisiología del crecimiento  

Microsoft Academic Search

ExtractoEl crecimiento humano es un proceso dinámico y complejo que comienza con la fertilización del óvulo y se completa con la fusión de las epífisis y las metáfisis de los huesos largos, que caracteriza la terminación de la adolescencia. El crecimiento ocurre en fases, con características distintivas en términos de influencias dominantes derivadas de factores y patrones genéticos, ambientales\\/nutricionales y

Arlan L. Rosenbloom

2007-01-01

262

La crisis del neoliberalismo  

Microsoft Academic Search

En este artículo se analiza la actual crisis en relación al modelo de gestión neoliberal de las economías capitalistas durante los treinta últimos años. En primer lugar se caracterizan los rasgos básicos de la regulación neoliberal. En segundo lugar se analiza la crisis actual en relación a estos rasgos, en concreto se considera el papel del sector financiero, el funcionamiento

Albert Recio Andreu

2009-01-01

263

-DERECHO PBLICO DEL ESTADO AUTONMICO La implantacin del Mster universitario en Derecho Pblico del Estado Autonmico  

E-print Network

- DERECHO P�BLICO DEL ESTADO AUTON�MICO La implantación del Máster universitario en Derecho Público del Estado Autonómico extinguirá el Máster Oficial en Derecho Autonómico y Local. Por esta razón se materias del Máster Oficial en Derecho Autonómico y Local. Los estudiantes que comenzaron el Máster Oficial

Rey Juan Carlos, Universidad

264

The Del Rio ataxite, Texas  

NASA Technical Reports Server (NTRS)

Basic data are presented on the Del Rio, Nordheim, and Monahans ataxites found in Texas. Results are reported for bulk-chemistry analysis, metallographic observations, and electron-microprobe analysis of the Del Rio meteorite. It is shown that Del Rio is distinctly different from the other two ataxites in terms of nickel, phosphorous, and carbon content, and is composed of at least three coarse grains in different crystallographic orientations. All the kamacite in Del Rio is found to have transformation structures that are probable shock products, and minor inclusions of daubreelite, schreibersite, and troilite are observed. It is concluded that Del Rio was apparently mildly shocked prior to its fall.

Henderson, E. P.; King, E. A.

1977-01-01

265

Nevado del Huila, Columbia  

NASA Technical Reports Server (NTRS)

Nevado del Huila Volcano in Colombia is actually a volcanic chain running north to south, capped by a glacier. With peaks ranging in height from 2,600 to 5,780 meters (8,530 to 18,960 feet), Nevado del Huila is a stratovolcano composed of alternating layers of hardened lava, solidified ash, and volcanic rocks. Its first recorded eruption occurred in the mid-sixteenth century. The long-dormant volcano erupted again in mid-April 2007. A few months before the eruption, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of Nevado del Huila, on February 23, 2007. In this image, the bright white area just east of the central summit is ice. Immediately west of the summit are bare rocks, appearing as blue-gray. West of those rocks, white reappears, but this patch of white results from clouds hovering in the nearby valley. In the east, the colors turn to brown (indicating bare rock) and bright green (indicating vegetation). ASTER photographed Nevado del Huila near the end of a long phase of quietude. On April 17, 2007, local authorities recorded seismic activity associated with rock fracturing on the volcano's central summit, according to the ReliefWeb Website. Activity intensified the following day with an eruption and mudflows, forcing thousands of nearby residents to evacuate. As the Associated Press reported, the eruption caused avalanches and floods that wiped away both houses and bridges. It marked the volcano's first recorded eruption since the Spanish colonized the area five centuries earlier. NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

2007-01-01

266

Diseño y optimización del procesamiento térmico de alimentos envasados.  

E-print Network

??Contiene: Introducción; Objetivos; Diseño del procesamiento térmico: antecedentes; Diseño del procesamiento térmico: materiales y métodos; Diseño del procesamiento térmico: resultados y discusión; Optimización del procesamiento… (more)

Ansorena, María Roberta

2009-01-01

267

DIAGNOSTICO DE LA TUBERCULOSIS INFANTIL EN PROVINCIAS DE LA ARGENTINA  

Microsoft Academic Search

Diagnosis of tuberculosis in children in provinces of Argentina. Confirming the diagnosis of pedia- tric tuberculosis is cumbersome, due to the clinical features (generally paucibacillary forms) of the disease. This national study was undertaken in order to establish: the features of childhood tuberculosis at the time of diagnosis, the criteria on which the pediatricians based the diagnosis, the bacteriologic contribution

MARIA DELFINA SEQUEIRA; MARIA SUSANA IMAZ; LUCIA BARRERA; GRACIELA H. POGGIO; OMAR A. LATINI

268

The dynamic stator stalk of rotary ATPases  

PubMed Central

Rotary ATPases couple ATP hydrolysis/synthesis with proton translocation across biological membranes and so are central components of the biological energy conversion machinery. Their peripheral stalks are essential components that counteract torque generated by rotation of the central stalk during ATP synthesis or hydrolysis. Here we present a 2.25-Å resolution crystal structure of the peripheral stalk from Thermus thermophilus A-type ATPase/synthase. We identify bending and twisting motions inherent within the structure that accommodate and complement a radial wobbling of the ATPase headgroup as it progresses through its catalytic cycles, while still retaining azimuthal stiffness necessary to counteract rotation of the central stalk. The conformational freedom of the peripheral stalk is dictated by its unusual right-handed coiled-coil architecture, which is in principle conserved across all rotary ATPases. In context of the intact enzyme, the dynamics of the peripheral stalks provides a potential mechanism for cooperativity between distant parts of rotary ATPases. PMID:22353718

Stewart, Alastair G.; Lee, Lawrence K.; Donohoe, Mhairi; Chaston, Jessica J.; Stock, Daniela

2012-01-01

269

Rotor-Stator-Kontakt polygonfrmigen Fanglagern  

E-print Network

PVC-Hülse: Exponent (Normalkraft): Steifigkeitsfaktor: Verlustbeiwert: Reibzahl (Maximalwert): 19,0 s: Periodische Bewegungen Laval-Rotor: Drehfrequenz f = 6 Hz Fanglager: starre Aufhängung, PVC-Hülse #12 Aufhängung, PVC-Hülse 3 4 6 8 12 18 24 36 72 rund Anzahl der Fangflächen m 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1

Pfeifer, Holger

270

Acerca del Centro para la Salud Mundial del NCI  

Cancer.gov

El Centro para la Salud Mundial (CGH) coordina y fija las prioridades en las actividades que lleva a cabo el Instituto Nacional del Cáncer a nivel mundial. Su objetivo es avanzar la investigación mundial del cáncer y reducir las muertes causadas por esta enfermedad.

271

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

272

Yeast DEL assay detects clastogens.  

PubMed

Chromosomal rearrangements, including DNA deletions are involved in carcinogenesis. The deletion (DEL) assay scoring for DNA deletions in the yeast Saccharomyces cerevisiae is able to detect a wide range of carcinogens. Among approximately 60 compounds of known carcinogenic activity, the DEL assay detected 86% correctly whereas the Ames Salmonella assay detected only 30% correctly [R.J. Brennan, R.H. Schiestl, Detecting carcinogens with the yeast DEL assay, Methods Mol. Biol. 262 (2004) 111-124]. Since the DEL assay is highly inducible by DNA double strand breaks, this study examined the utility of the DEL assay for detecting clastogens. Ten model compounds, with varied mechanisms of genotoxicity, were examined for their effect on the frequency of DNA deletions with the DEL assay. The compounds tested were: actinomycin D, camptothecin, methotrexate and 5-fluorodeoxyuridine, which are anticancer agents, noscapine and furosemide are therapeutics, acridine, methyl acrylate and resorcinol are industrial chemicals and diazinon is an insecticide. The in vitro micronucleus assay (IVMN) in CHO cells, a commonly used tool for detection of clastogens, was performed on the same compounds and the results of the two assays were compared. The results of our study show that there is 70% concordance in the presence of metabolic activation (rat liver S9) and 80% concordance in the absence of metabolic activation between the DEL assay and the standard in vitro micronucleus assay. The lack of cytotoxicity observed for four of the ten compounds examined indicates limited diffusion of lipophilic compounds across the yeast cell wall. Thus, the development of a more permeable yeast tester strain is expected to greatly improve concordance of the DEL assay with the IVMN assay. The yeast DEL assay is inexpensive, amenable to automation and requires less expertise to perform than the IVMN. Thus, it has a strong potential as a robust, fast and economical screen for detecting clastogens in vitro. PMID:15781217

Kirpnick, Zhanna; Homiski, Michael; Rubitski, Elizabeth; Repnevskaya, Marina; Howlett, Niall; Aubrecht, Jiri; Schiestl, Robert H

2005-04-01

273

Se da a conocer el plan del Instituto Nacional del Cáncer para acelerar la investigación del cáncer  

Cancer.gov

En la 100va Reunión Anual de la Asociación Estadounidense de Investigación del Cáncer realizada en Denver, el director del Instituto Nacional del Cáncer, doctor John E. Niederhuber, dio a conocer detalles importantes, tales como financiamiento de más subvenciones, creación de una plataforma para atención personalizada del cáncer y un programa acelerado de genética del cáncer que hará avanzar la investigación oncológica en este nuevo ambiente económico.

274

Harold Varmus investido bajo juramento como 14.º director del Instituto Nacional del Cáncer  

Cancer.gov

Ganador del Premio Nobel, doctor Harold E. Varmus, prestó juramento hoy como 14.º director del Instituto Nacional del Cáncer (NCI).  "Es muy estimulante que estés de regreso con nosotros", dijo la secretaria del Departamento de Salud y Servicios Humanos Kathleen Sebelius en la ceremonia de toma de juramento. “Hoy se abre un nuevo capítulo para el Instituto Nacional del Cáncer”.

275

Impactos del Huracn Isaac en la calidad del agua en Luisiana con MODIS 250m  

E-print Network

lluvias. Por tal razón se quiere estudiar la calidad del agua en el delta del río Mississippi antes1 Impactos del Huracán Isaac en la calidad del agua en Luisiana con MODIS 250m Thais J. Alicea imágenes en ENVI. Palabras clave: Calidad del agua, ENVI, Isaac, Luisiana, MODIS

Gilbes, Fernando

276

VERBALE DEL CONSIGLIO DEL CORSO DI STUDIO INFORMATICA E TECNOLOGIE PER LA PRODUZIONE DEL del 14 Maggio 2008  

E-print Network

relative agli anni precedenti 4. Manifesti degli Studi 5. Elezione Presidenti Corsi di Studio: adempimenti ingiustificati. PROFESSORI ORDINARI, STRAORDINARI ED ASSOCIATI 1. V. ALBINO SOFTWARE del 21 Febbraio 2008 3. P. BUONO....................... .................. 4. V. CAPRIATI

Malerba, Donato

277

Historia del IAC PRIMERAS EXPEDICIONES  

E-print Network

Astrofísica de Canarias - el Observatorio del Teide, en Tenerife,y el Observatorio del Roque de los Muchachos a esta conclusión después de observar a diversos niveles en Tenerife, desde el mar hasta la montaña de Tenerife que propuso la creación de un observatorio internacional en la Montaña de Guajara. #12;ECLIPSE DE

278

Gestin del agua en producciones  

E-print Network

160 cm 220cm PER 240cm Gestión del agua en producciones de secano #12;#12;Sitio Prof. cm pH CE mmoh 31 oct s/napa soja Maíz Girasol Uso del agua - PER ­ sección control- relación con precipitaciones: Escenario lluvia alta -180,0 -160,0 -140,0 -120,0 -100,0 -80,0 -60,0 -40,0 -20,0 0,0 20/07/2012 19

Nacional de San Luis, Universidad

279

SUPUESTOS IMPLÍCITOS EN LA UTILIZACIÓN DEL CAPITAL ASSETS PRICING MODEL – CAPM PARA EL CÁLCULO DEL COSTO DEL CAPITAL PROPIO – EQUITY  

Microsoft Academic Search

El artículo evidencia los supuestos y problemas que implica la utilización del Capital Assets Pricing Model– CAPM en el cálculo del costo del capital propio de las empresas – Equity, haciendo énfasis en la diferencia que existe entre la forma como toman sus decisiones de inversión quienes lo hacen en el mercado de valores y quienes lo hacen en una

Carlos Arturo Gómez Restrepo; Mario García Molina

2011-01-01

280

Instantánea del cáncer de seno (mama)  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de seno (mama); así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

281

Instantánea del cáncer de cuello uterino  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de cuello uterino; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

282

Rafael Molina Bases del filtro de Kalman 1 Bases del filtro de Kalman  

E-print Network

Rafael Molina Bases del filtro de Kalman 1 Bases del filtro de Kalman Rafael Molina Soriano Depto Ciencias de la Computación e IA Universidad de Granada #12;Rafael Molina Bases del filtro de Kalman 2 Contenidos ! Introducción. ! El filtro de Kalman " Modelo del sistema " Modelo de medida " Formulación de la

Granada, Universidad de

283

Reglament d'organitzaci i funcionament del departament de Teoria del Senyal i Comunicacions  

E-print Network

Reglament d'organització i funcionament del departament de Teoria del Senyal i Comunicacions Acord departament de Teoria del Senyal i Comunicacions · Document proposta informat favorablement per la Comissió de/07/2014 Secretaria general 21 de juliol de 2014 #12;REGLAMENT D'ORGANITZACI� I FUNCIONAMENT DEL DEPARTAMENT DE TEORIA

Yannuzzi Sanchez, Marcelo

284

La evolución de la geografía y del trabajo del geógrafo en Rusia  

Microsoft Academic Search

La geografía rusa se fomentó, desde finales del siglo XIX, como una ciencia práctica en relación directa con el desarrollo económico del país. El trabajo del geógrafo, que evolucionó bajo la influencia de los avatares políticos, económicos y sociales, se centra sobre los estudios naturalistas y utilitaristas del espacio geográfico en el caso de la geografía física –área dominante en

Marina Frolova

2007-01-01

285

SERVICIO DE DEPORTES NORMATIVA DE USO DEL  

E-print Network

SERVICIO DE DEPORTES NORMATIVA DE USO DEL SERVICIO DE FISIOTERAPIA #12;ÍNDICE EXPOSICI�N DE MOTIVOS..................................................................................... 4 #12;NORMATIVA DE USO DEL SERVICIO DE FISIOTERAPIA VICERRECTORADO DE CULTURA, DEPORTES Y POLÍTICA datos del Servicio de Deportes y que formen parte de los siguientes programas: a) Jugadores/as de los

Escolano, Francisco

286

REFLEXIONES ÉTICAS A PARTIR DEL PROYECTO UNASUR  

Microsoft Academic Search

Este artículo pretende identificar los principios éticos del proyecto UNASUR tomando como punto de partida el discurso pronunciado por Luiz Inácio Lula da Silva en mayo del 2008 en Brasilia y entrevistas realizadas por representantes de Prensa Latina. Se analiza este documento por ser Lula uno de los fundadores del proyecto de La Unión de Naciones Suramericanas (UNASUR), demostrando la

Cintia Beatriz Pérez Lanza; Ana Maria Infante Aguilar

2011-01-01

287

EVOLUZIONE-WEB -1 -Evoluzione del Web  

E-print Network

EVOLUZIONE-WEB - 1 - Evoluzione del Web (fonte prof. Polillo) #12;- 2 - L'evoluzione del web EVOLUZIONE-WEB · Dal primo sito Web (1991) il Web è in continua crescita, e in continua evoluzione tecnologia, il mercato, i comportamenti delle persone · Le fasi della storia del Web: Web 1.0, Web 2.0, il

De Antonellis, Valeria

288

Tratamiento actual del estreñimiento infantil  

Microsoft Academic Search

ResumenEl estreñimiento infantil es un problema mundial. Es una de las molestias más comunes que tienen que afrontar tanto los pediatras generales como los gastroenterólogos pediátricos. El tratamiento del estreñimiento crónico es problemático, a menudo exige un seguimiento a largo plazo y el uso de medicamentos. A pesar de su elevada frecuencia, se han realizado pocos ensayos aleatorizados para investigar

Olivia Liem; Carlo Di Lorenzo; Jan A. J. M Taminiau; Hayat M. Mousa; Marc A. Benninga

2007-01-01

289

La Universidad de Alicante organiza una observacin del eclipse de Luna del mircoles  

E-print Network

La Universidad de Alicante organiza una observación del eclipse de Luna del miércoles La Universidad de Alicante ha preparado una observación del eclipse total de Luna que se producirá la noche del astronómica así como su instrumental con el fin de explicar el desarrollo del eclipse. Previo a la observación

Escolano, Francisco

290

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.

291

El astrologo y el Emperador del Ganges1 Nota preliminar  

E-print Network

El astr´ologo y el Emperador del Ganges1 Nota preliminar El explorador y aventurero Sir Richard~nos las Actas de las audiencias del Emperador del Ganges, pero apenas logr´o recopilar algunos de los comunicante: Las audiencias del Emperador del Ganges eran re- gistradas en Actas, con todo lujo de detalles

Fernández Gallardo, Pablo

292

El Corral del Veleta: enclave geográfico singular del Parque Nacional de Sierra Nevada  

Microsoft Academic Search

Resumen: La unidad del Veleta, por sus valores científicos y culturales, es enclave singular del Parque Nacional de Sierra Nevada. En particular, su Corral, que fue reducto glaciar durante la Pequeña Edad del Hielo y que aún alberga hielo fósil y permafrost alpino. Al tratarse de reducto recién deglaciado se desarrollan procesos morfogénicos fríos de especial relevancia. También señalar de

Antonio Gómez Ortiz

293

Estudio bibliométrico de los modelos de medición del concepto de calidad percibida del servicio en Internet  

Microsoft Academic Search

P a l a b r a s c l a v e : marketing de servicios, calidad del servicio al cliente, calidad del servicio en Internet, modelos de evaluación de la calidad del servicio. a b s t r a c t A b i b l i o m e t r i c a n a l

Edison Jair; Duque Oliva; Amparo Cervera Taulet; Carlos Rodríguez Romero

294

Control del dolor: Apoyo para las personas con cáncer  

Cancer.gov

Libro sobre el control del dolor en pacientes con cáncer. Cubre los métodos y medicinas, así como los efectos físicos y emocionales del dolor. Es una adaptación cultural para el público de habla hispana del libro en inglés Pain Control.

295

Le rane delle risaie Osservazioni sugli Iperolidi del  

E-print Network

boettgeri finora è stato segnalato sol- tanto nell'estremo Sudest del Mada- gascar. Si rimanda alle cartine boettgeri) si somigliano molto. Le rane del genere Heterixalus, a seconda della specie e del luogo di

296

CLASSIFICAZIONE MORFOLOGICA QUANTITATIVA DEL TERRITORIO ITALIANO TRAMITE WAVELET  

E-print Network

CLASSIFICAZIONE MORFOLOGICA QUANTITATIVA DEL TERRITORIO ITALIANO TRAMITE WAVELET M. De Agostino una rappresentazione quantitativa della morfologia dell'intero territorio italiano, al fine di del terreno. Il risultato finale della procedura è costituito dalla divisione del territorio italiano

Poggi, Davide

297

SERVICIO DE DEPORTES NORMATIVA DE ACTUACIN DEL  

E-print Network

SERVICIO DE DEPORTES NORMATIVA DE ACTUACI�N DEL PERSONAL AUXILIAR DE INSTALACIONES DEPORTIVAS CULTURA, DEPORTES Y POLÍTICA LING�ÍSTICA 3 NORMATIVA DE ACTUACI�N DEL PERSONAL AUXILIAR DE INSTALACIONES VICERRECTORADO DE CULTURA, DEPORTES Y POLÍTICA LING�ÍSTICA 4 · Entrega de las llaves de los vestuarios al

Escolano, Francisco

298

Mercato del carbonio e settore forestale: buone  

E-print Network

'ambito del PK D. Le scelte del Governo italiano Definizioni · 1 credito = 1 t CO2 equivalente (eq) · Eq = il in equivalenti di CO2 · 1 t C eq = 3,66 t CO2 eq #12;11-10-2012 2 Regole e buone prassi · MARC Quando si opera

Pettenella, Davide

299

Aspectos macroeconómicos del plan de desarrollo  

Microsoft Academic Search

Poco después de la apertura, la economía inició un ciclo de crecimiento rápido y acumulación de déficits, seguido por otra etapa de correctivos monetarios que frenan el crecimiento, pero que no eliminan las causas del desiquilibrio. El Plan de Desarrollo reduce el déficit fiscal y es probable que la próxima fase de expansión dure 3 años, en lugar del año

Luis Lorente

1999-01-01

300

Teoría del discurso y derechos humanos  

Microsoft Academic Search

En esta obra Alexy desarrolla su fundamentación de las decisiones judiciales o teoría de la argumentación jurídica. Su concepción es eminentemente racional y parte de la teoría del discurso de Habermas, en el intento de lograr un modelo de argumentación jurídica que corresponda al Estado constitucional democrático. La singularidad del punto de vista que aquí expone radica en que considera

Robert Alexy

301

CAPÍTULO 4. ANÁLISIS DEL DISCURSO: DISCURSO DEL EMPERADOR HIROHITO CON MOTIVO DE LA RENDICIÓN DE JAPÓN DE LA GUERRA DEL PACÍFICO  

Microsoft Academic Search

El ACD se encuadra en el marco teórico del Análisis del Discurso, teoría que otorga al discurso la dimensión de práctica social. En el ACD se explota esta vertiente social del uso del lenguaje, profundizando en las relaciones sociales e ideológicas que se establecen entre el texto y el contexto. El discurso se concibe como un concepto tridimensional: discurso como

Raquel Rubio Martín

302

¿Cómo puedo usar los servicios del CIS?  

Cancer.gov

El Servicio de Información sobre el Cáncer del Instituto Nacional del Cáncer maneja también la línea telefónica para dejar de fumar 1-877-448-7848 (1-877-44U-QUIT), la cual proporciona información gratuita para dejar de fumar y apoyo a fumadores que desean dejar el tabaco. Nuestro servicio no tiene ningún costo ni cuota de pago. El servicio se brinda en inglés y en español, de lunes a viernes de 8 de la mañana a 8 de la noche, hora del Este.

303

Caracas: Escenario del mundo (V Festival Internacional de Teatro)  

E-print Network

Guerra Mundial. EL TEATRO IRREVERENTE DEL BRASIL: UNA EPOPEYA TROPICAL Pero si hubo un conjunto dramático que casi ocasiona un motín a la en trada del teatro ese fue el Grupo Macunaíma del Brasil con su obra Macu- naíma basada en la novela homónima del...

Má rceles Daconte, Eduardo

1981-10-01

304

Un analisis internacional del gasto publico en educacion  

Microsoft Academic Search

En este trabajo analizamos la evolucion del gasto en educacion en 9 paises de la OCDE en el periodo 1985-92. Se estudia la trayectoria del gasto en educacion en %PIB y en funcion del numero de alumnos, relacionado ambos con la capacidad economica de cada pais expresada a traves del PIB per capita. Mediante de un modelo econometrico analizamos la

Ana Iglesias; Isabel Neira

1996-01-01

305

Departamento de Filosofa del Derecho y Derecho Internacional Privado Presentacin  

E-print Network

Departamento de Filosofía del Derecho y Derecho Internacional Privado Presentación El Departamento de Filosofía del Derecho y Derecho Internacional Privado está compuesto por las siguientes áreas de personalizada, los profesores del Departamento de Filosofía del Derecho y Derecho Internacional Privado ruegan

Escolano, Francisco

306

Teatro chileno en la década del 80  

E-print Network

la lucha moral intimista, como el clásico Deja que los perros ladren, de Sergio Vodanovic. Aunque el teatro chileno desdeñó SPRING 1992 83 habitualmente del panfleto más efectista, sí tuvo un compromiso con las grandes utopías y demandas... su producción conjunta y no existir esa clásica separación de roles, al borrarse las fronteras, también se han aminorado los conflictos y las angustias de ambas partes. Estas tres caracterizaciones del teatro chileno de los últimos años—teatro de...

Piñ a, Juan André s

1992-04-01

307

COLOMBIA: El IV Festival del Nuevo Teatro  

E-print Network

cabeza de Gu\\up, reúne y elabora todas sus experiencias anteriores, superando fracasos y desarrollando necesidades del público callejero. Es una creación colectiva basada en una imagen del Popól Vuh10 con texto de Juan Carlos Moyano, dirección de Jorge.... Gabriel García Márquez, Todos los cuentos de Gabriel García Márquez (La Habana: Casa de las Américas, 1968), pp. 268-277. Colección La Honda. 10. Popol Vuh, Antiguas historias de los indios quichés de Guatemala (Mexico: Editorial Porrúa, 1965). Cabe...

Gonzá lez, Patricia E.

1980-10-01

308

rgano informativo del Colegio de Ciencias y Humanidades Suplemento especial  

E-print Network

Número 3 9 de mayo de 2011 �rgano informativo del Colegio de Ciencias y Humanidades SuplementoCCHSuplementoespecialnúmero3,9demayode20114 La Dirección General del Colegio de Ciencias y Humanidades, a través del elementos básicos del método epidemi- ológico para su aplicación en curso de Ciencias de la Salud, del nivel

Islas, León

309

Serie de Derecho Económico 1. Casos de estudio de aplicación del Análisis Económico del Derecho  

Microsoft Academic Search

El interés por el estudio del Análisis Económico del Derecho –AED– no es nuevo. En su versión clásica, que corresponde a la Escuela de Chicago, y también en las versiones más recientes como la nueva economía institucional, el AED resulta ser una herramienta útil para estudiar problemas jurídicos, la forma de incidir de la regulación en el desarrollo y en

Varios

310

Dr. Matas Alvarado (CV breve) Investigador Titular del Departamento de Computacin del CINVESTAV; Miembro Regular de  

E-print Network

Dr. Matías Alvarado (CV breve) Investigador Titular del Departamento de Computación del CINVESTAV. JOS� MATÍAS ALVARADO MENTADO Curriculum Vitae DATOS PROFESIONALES Investigador CINVESTAV 3B (Febrero JCR ISI 1. Alvarado Matias, Sheremetov, L., Bañares, R. & Cantú, F. (Guest Eds.) Special Issue

Alvarado, Matías

311

La capacidad de carga psicológica del turista como indicador del turismo sostenible  

Microsoft Academic Search

La capacidad de carga turística ostenta un interés creciente dado que se vincula estrechamente con el desarrollo turístico sostenible. Se preten- de justificar la utilidad de este concepto mediante una propuesta metodo- lógica sencilla y eficaz, analizando la capacidad de carga psicológica del turista. En la aplicación empírica se detecta que la satisfacción del turista disminuye cuando los niveles de

Jesús Manuel López Bonilla; Luis Miguel; López Bonilla

312

El uso del agua en Níjar: Implicaciones ambientales del modelo actual de gestión  

Microsoft Academic Search

RESUMEN Níjar, municipio del SE almeriense, experimenta, hoy por hoy, una coyuntura de escasez del agua sin precedentes. El modelo de gestión actual, basado en la explotación de las aguas subterráneas, y protagonizado por una agricultura intensiva en crecimiento y una incipiente actividad turística, ha conducido al progresivo agotamiento de los acuíferos locales. En respuesta a tal coyuntura, se implementan

Francisco Javier Toro Sánchez

2008-01-01

313

Las representaciones fácticas y cognitivas del relato de entrevistas biográficas : un análisis reticular del discurso  

Microsoft Academic Search

Este artículo trata de identificar y relacionar las dimensiones fácticas y cognitivas de un relato biográfico, entendido como una representación narrativa. El entrevistado construye su narración entreverando ambas dimensiones a lo largo del relato. Este artículo propone un método de análisis reticular del discurso como un procedimiento eficaz para poner de relieve y relacionar ambas dimensiones. A partir de teorías

Carlos Lozares Colina

2006-01-01

314

Terapias con inhibidores del receptor del factor de crecimiento epidérmico: acercando el futuro  

Microsoft Academic Search

RESUMEN La función esencial del receptor del factor de crecimiento epidérmico (REGF) en diversos tipos de tumores sólidos lo ha convertido en un blanco fundamental para el diseño de nuevas drogas. La contribución de las vías de señalización asociadas al REGF en procesos tumorales como la proliferación celular, la angiogénesis y la resistencia a apoptosis ha sido bien establecida. Dos

Arlhee Díaz; Agustín Lage

2007-01-01

315

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.

316

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

317

Evaluation of Steam Turbines Triangular Tooth on Stator Labyrinth Seal  

E-print Network

, mm ? - Divergence angle ? - Kinetic energy carryover coefficient ? - Fraction of kinetic energy carried over ?- Expansion coefficient Re - Reynolds number based on clearance, ????? ? - Dynamic viscosity, Pa/s CD - Discharge... .......................... 85? Fig. 4.6. Discharge coefficient of the seal with four teeth ...................................... 86? xvi Fig. 4.7. Deviation of Cd values at different tooth position for Re ........................ 87? Fig. 4.8. Association of Cd...

Tanvir, Hossain Ahmed

2012-07-16

318

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

319

Stator for Rotating Electrical Machine Having Multiple Controlwindings  

SciTech Connect

A rotating electric machine is provided which includes multiple independent control windings for compensating for rotor imbalances and for levitating/centering the rotor. The multiple independent control windings are placed at different axial locations along the rotor to oppose forces created by imbalances at different axial locations along the rotor. The multiple control windings can also be used to levitate/center the rotor with a relatively small magnetic field per unit area since the rotor and/or the main power winding provides the biasfield.

Shah, Manoj R.; Lewandowski, Chad R.

1999-05-05

320

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

321

Induction machine faults detection using stator current parametric spectral estimation  

NASA Astrophysics Data System (ADS)

Current spectrum analysis is a proven technique for fault diagnosis in electrical machines. Current spectral estimation is usually performed using classical techniques such as periodogram (FFT) or its extensions. However, these techniques have several drawbacks since their frequency resolution is limited and additional post-processing algorithms are required to extract a relevant fault detection criterion. Therefore, this paper proposes a new parametric spectral estimator that fully exploits the faults sensitive frequencies. The proposed technique is based on the maximum likelihood estimator (MLE) and offers high-resolution capabilities. Based on this approach, a fault criterion is derived for detecting several fault types. The proposed technique is assessed using simulation signals, issued from a coupled electromagnetic circuits approach-based simulation tool for mechanical unbalance and electrical asymmetry faults detection. It is afterward validated using experiments on a 0.75-kW induction machine test bed for the particular case of bearing faults.

El Bouchikhi, El Houssin; Choqueuse, Vincent; Benbouzid, Mohamed

2015-02-01

322

A study of viscous flow in stator and rotor passages  

NASA Technical Reports Server (NTRS)

A numerical technique to predict the viscous behavior in the three-dimensional domain of rotating and stationary blade passages is presented. The analysis is based upon the numerical integration of the incompressible Navier-Stokes equations. An approach is taken to combine the three momentum equations and the continuity equation into two sets of vorticity transport-stream function equations. These equations are expressed along families of arbitrarily defined orthogonally intersecting surfaces placed within the blade passage. Unlike the stream surfaces, the arbitrary surfaces allow fluid to flow across. The numerical code employs a nonorthogonal body fitted coordinate system on each of the intersecting surfaces. The solution process involves the iterative combination of the solutions on the two families of intersecting surfaces for a complete solution. The results of flow in thin blade stationary and rotating polar ducts is presented.

Sheoran, Y.; Tabakoff, W.

1982-01-01

323

Turbine rotor-stator leaf seal and related method  

DOEpatents

A seal assembly for installation between rotating and stationary components of a machine includes a first plurality of leaf spring segments secured to the stationary component in a circumferential array surrounding the rotating component, the leaf spring segments each having a radial mounting portion and a substantially axial sealing portion, the plurality of leaf spring segments shingled in a circumferential direction.

Herron, William Lee (Cincinnati, OH); Butkiewicz, Jeffrey John (Simpsonville, SC)

2003-01-01

324

El teatro en el XVII Congreso del IILI en Filadelfia  

E-print Network

42 LATIN AMERICAN THEATRE REVIEW El teatro en el XVII Congreso del IILI en Filadélfia La segunda parte del XVII Congreso de Literatura Iberoamericana del In stituto Internacional de Literatura Iberoamericana se celebró en la Universidad de... Pennsylvania, en Filadélfia, durante la semana del 24 al 29 de agosto de 1975 (la primera de había efectuado en Madrid y Sevilla del 20 al 26 de marzo de dicho año—véase LATR, 8/2, Spring 1975, pág. 50). El tema del congreso fue el su rrealismo y la...

Gutié rrez de la Solana, Alberto

1976-04-01

325

Extensión del Formalismo de Orbitales de Defecto Cuántico al tratamiento del efecto Stark (SQDO).  

NASA Astrophysics Data System (ADS)

El estudio experimental de las interacciones de átomos Rydberg altamente excitados con campos eléctricos ha experimentado un creciente interés durante las dos últimas décadas debido, en gran medida, al desarrollo de nuevas técnicas para crear y estudiar átomos Rydberg en el laboratorio. Acompañando a estas nuevas técnicas experimentales, es necesario el desarrollo de modelos teóricos que nos permitan contrastar sus medidas y conocer mejor los fundamentos de los mismos. Desde el punto de vista teórico el conocimiento del desdoblamiento de los niveles energéticos de un átomo en función de la magnitud del campo eléctrico aplicado (lo que se conoce como mapa Stark) es el mejor punto de partida para la descripción del sistema y un prerrequisito fundamental para el cálculo de distintas propiedades atómicas en presencia del campo eléctrico tales como intensidades de transición, umbrales de ionización de campo eléctrico, tiempos de vida, posición y anchura de cruces evitados, etc. En este trabajo presentamos la adaptación del método de orbitales de defecto cuántico [1,2,3] al tratamiento del efecto Stark (SQDO) [4] y su aplicación al cálculo de los desdoblamientos energéticos y fuerzas de oscilador de estados Rydberg en los átomos de Li, Na y K. El propósito de este estudio es, por un lado, desarrollar métodos fiables para la determinación de propiedades atómicas en presencia de campos eléctricos y, por otro, mostrar la fiabilidad de las funciones de onda QDO en la descripción del efecto Stark en sistemas atómicos.

Menéndez, J. M.; Martín, I.; Velasco, A. M.

326

III Festival del Siglo de Oro (Chamizal)  

E-print Network

SPRING 1978 111 III Festival del Siglo de Oro (Chamizal) E. JARABA-PARDO El Siglo de Oro fue, por la fecundidad de los autores y por las influencias trascendentales de sus obras en el posterior desarrollo de la dramaturgia universal, uno de los... períodos más importantes en la historia del teatro. Algunos de sus rasgos esenciales fueron el uso de un lenguaje popular, satírico, e irónico, la introducción de personajes de las clases bajas, tales como esclavos y sirvientes, y la irreverencia a las...

Jaraba-Pardo, E.

1978-04-01

327

Transformación de los programas de estudios clínicos del NCI  

Cancer.gov

Información sobre los programas e iniciativas del NCI que patrocinan, realizan, crean o apoyan estudios clínicos, entre los que se incluyen la Red Nacional de Estudios Clínicos (NCTN) y el Programa de Investigación Oncológica Comunitaria (NCORP) del NCI.

328

PROGRAMMA DEL CORSO "Teoria dei Modelli" DOCENTE: Alessandro Berarducci  

E-print Network

PROGRAMMA DEL CORSO "Teoria dei Modelli" DOCENTE: Alessandro Berarducci Anno di corso: 2009 CONTENUTI DELL'INSEGNAMENTO: Introduzione alle nozioni fondamentali della teoria dei modelli con compagne. Amalgamazione ed eliminazione dei quan- tificatori. Teoria degli ordini discreti. Teoria del

Berarducci, Alessandro

329

Student Competition: Siting Potential Dams at Camp Del Webb, Utah  

E-print Network

Siting Potential Dams at Camp Del Webb, Utah Presented By: Kyle Wamser Problem ? Camp Del Webb is Lacking an Onsite Lake ? High Adventure Bases generally need aquatics ? Large lake nearby, but transportation is required ? Possible Solution...

Wamser, William Kyle

2007-11-14

330

Centro para la Salud Mundial (CGH) del NCI  

Cancer.gov

El Centro para la Salud Mundial (CGH) del Instituto Nacional del Cáncer coordina actividades de investigación y trabaja con socios nacionales e internacionales para comprender y enfrentar la carga que representa el cáncer a nivel mundial.

331

La evolución estilística del teatro de Aguilera-Malta.  

E-print Network

centroamericano de administración y clientela blanca y de músicos negros, en esta pieza el autor reprueba franca mente, aunque con la lenificación que proveen la ironía del desenlace y lo espectacular del breve cuadro, la discriminación practicada contra el...

Luzuriaga, Gerardo

1970-04-01

332

Analisis cuantitativo del gasto en educacion en Europa  

Microsoft Academic Search

El objetivo de este trabajo es analizar la situacion del gasto publico total en educacion para nueve paises de la OCDE entre los que se encuentra España, en el periodo 1985-1992. Para ello comparamos el gasto en estos paises desde diferentes perspectivas, en funcion del PIB, gasto por alumno, porcentaje del gasto en los diferentes niveles educativos sobre el total,

Isabel Neira; M. Carmen Guisan; X. A. Rodriguez

1997-01-01

333

APORTES TEÓRICO-METODOLÓGICOS PARA EL ESTUDIO DE LA PRODUCCIÓN SOCIAL DE SENTIDO A TRAVÉS DEL ANÁLISIS DEL DISCURSO PRESIDENCIAL  

Microsoft Academic Search

Este artículo presenta un enfoque teórico-metodológico para el estudio de las significaciones políticas. Se apunta a contribuir a la reflexión acerca del papel del discurso presidencial en la construcción de una \\

Víctor Armony

2005-01-01

334

UNIVERSIDAD SIMON BOLIVAR SEDE DEL LITORAL  

E-print Network

POSTGRADO DENOMINACI�N: C�DIGO: ASIGNATURA: REDES DE DATOS (Capas 1, 2 y 3) TI-7312 REQUISITOS: TRANSMISI�N: Al finalizar la asignatura Redes de Datos (Capas 1, 2 y 3), el estudiante deberá manejar los conceptos básicos relacionados con las comunicaciones en las redes de datos en las capas 1, 2 y 3 del modelo

Vásquez, Carlos

335

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

336

El impacto macroeconómico del control de importaciones  

Microsoft Academic Search

A pesar de su uso generalizado como instrumento de política económica, tanto en los países desarrollados (entre las décadas del treinta y el cincuenta y nuevamente en los años setenta) como en las naciones en vía de desarrollo, los controles directos a las importaciones han tenido una vida teórica clandestina. Esto refleja, no sólo el recelo de los economistas neo-clásicos

José Antonio Ocampo

1985-01-01

337

Aproximaciones al análisis económico del derecho  

Microsoft Academic Search

Durante las últimas décadas la metodología de estudio que plantea el análisis económico del Derecho ha tomado gran importancia en todo el mundo,y es acompañada y respaldada por un prolífico volumen de publicaciones e investigadores, que día tras día la utilizan para evaluar los posibles caminos y consecuencias que las construcciones y desarrollos legales pueden tener sobre el comportamiento de

Mario A. Pinzón Camargo

338

GEOGRAFAAGRARIA (1 parte del Tema 1)  

E-print Network

parcelas Límites #12;EL SECANO El riego se limita a las aportaciones del agua de lluvia. La cantidad de lluvia caída matiza los secanos de las distintas áreas climáticas. Es posible dividir los secanos en dos

Escolano, Francisco

339

POLÍTICA TURÍSTICA DEL DEPARTAMENTO DE ANTIOQUIA  

Microsoft Academic Search

La importancia de la políticas para el adecuado desarrollo de la actividad turística es mayor de lo que normalmente se considera (Torres, 2004). Las autoridades regionales y locales desempeñan un papel fundamental en la formulación de políticas y en la organización y desarrollo del turismo. Esto ha sido durante mucho tiempo el caso de países como Alemania, Estados Unidos o

Claudia María Giraldo Velásquez; Sandra Zapata Aguirre

2010-01-01

340

akihiro kanamori L'ipotesi del continuo*  

E-print Network

tutti questi passi nel contesto di quei progressi fondamentali che hanno condotto alla moderna teoria ­ sarebbe diventato il più rilevante problema della teoria degli insiemi. Di più: lo sviluppo della teoria, sarebbe stato guidato dal problema del con- tinuo. In tutti i momenti critici in cui tale teoria si è

Kanamori, Akihiro

341

LA DIRECCIÓN DEL PROCESO DE INNOVACIÓN  

Microsoft Academic Search

RESUMEN El proceso de diseño y desarrollo de un nuevo producto es, en la actualidad, para las em- presas, una de las más importantes fuentes de ventajas competitivas sostenibles a largo plazo. Sin embargo, para innovar, la empresa debe situarse fuera del equilibrio. Es precisamente la gran incer- tidumbre que caracteriza a este tipo de actividades, la que causa, que

García Rodríguez

1998-01-01

342

Stato di avanzamento del lavoro di tesi  

E-print Network

Stato di avanzamento del lavoro di tesi Luca Malagoli Dipartimento di Fisica e Tecnologie Relative in attesa di pubblicazione · Le scuole di storia della fisica, (con C.Romagnino), in uscita su La fisica for the history of Sciences · Premio Nobel per la fisica 2008: un caso paradigmatico per la storia della fisica

Spagnolo, Filippo

343

Facultad de Derecho DATOS DEL ALUMNO  

E-print Network

Facultad de Derecho DATOS DEL ALUMNO APELLIDOS 1º 2º NOMBRE NIF DIRECCI�N LOCALIDAD CP PROVINCIA EMAIL TFNO. FIJO TFNO. MOVIL IMPORTANTE Para obtener los correspondientes títulos de Derecho y ADE, el elección, con los siguientes requisitos: - Los créditos de libre elección necesarios son 30,5 para Derecho

Escolano, Francisco

344

Del Mod System. 1972 Annual Report.  

ERIC Educational Resources Information Center

The overall aim of the Del Mod System is the improvement of science programs taught in Delaware schools; it is a working agreement among the University of Delaware, Delaware Technical and Community College, Delaware State College, State Department of Public Instruction, industry, and the schools. It was formed to bring about changes in science…

Purnell, Charlotte H.

345

MINOR DE COMPUTACION CIENTIFICA Nombre del Minor  

E-print Network

1 MINOR DE COMPUTACION CIENTIFICA Nombre del Minor Computación Científica Nombre en Inglés resuelve problemas científicos y/o de ingeniería seleccionando y utilizando las tecnología computacional

Rapaport, Iván

346

Elezione del Direttore del Dipartimento di Matematica Elenco provvisorio degli aventi diritto I affissione  

E-print Network

" BELTRAMETTI MAURO CLAUDIO " BOTTARO GIANFRANCO " BURLANDO LAURA " CONCA ALDO " GERAMITA ANTHONY VITO VERME FILIPPO " DE NEGRI EMANUELA " DEL PRETE VICENZA " DI BENEDETTO FABIO " GUALA ELDA " MORA FULVIO PAMELA " PERAZZO CECILIA " OLIVERI PAOLO " VERBOSIO FABIO " ONETO ALESSANDRO " TOZZO LAURA " CALEO

Robbiano, Lorenzo

347

Vigilando la Calidad del Agua de los Grandes Rios de la Nacion: El Programa NASQAN del Rio Grande (Rio Bravo del Norte)  

USGS Publications Warehouse

La Oficina del Estudio Geologico de los Estados Unidos (U.S. Geological Survey, 0 USGS) ha monitoreado la calidad del agua de la cuenca del Rio Grande (Rio Bravo del Norte) desde 1995 como parte de la rediseiiada Red Nacional para Contabilizar la Calidad del Agua de los Rios (National Stream Quality Accounting Network, o NASOAN) (Hooper and others, 1997). EI programa NASOAN fue diseiiado para caracterizar las concentraciones y el transporte de sedimento y constituyentes quimicos seleccionados, encontrados en los grandes rios de los Estados Unidos - incluyendo el Misisipi, el Colorado y el Columbia, ademas del Rio Grande. En estas cuatro cuencas, el USGS opera actualmente (1998) una red de 40 puntos de muestreo pertenecientes a NASOAN, con un enfasis en cuantificar el flujo en masa (la cantidad de material que pasa por la estacion, expresado en toneladas por dial para cada constituyente. Aplicacando un enfoque consistente, basado en la cuantificacion de flujos en la cuenca del Rio Grande, el programa NASOAN esta generando la informacion necesaria para identificar fuentes regionales de diversos contaminantes, incluyendo sustancias qui micas agricolas y trazas elementos en la cuenca. EI efecto de las grandes reservas en el Rio Grande se puede observar segun los flujos de constituyentes discurren a 10 largo del rio. EI analisis de los flujos de constituyentes a escala de la cuenca proveera los medios para evaluar la influencia de la actividad humana sobre las condiciones de calidad del agua del Rio Grande.

Lurry, Dee L.; Reutter, David C.; Wells, Frank C.; Rivera, M.C., (translator); Munoz, A.

1998-01-01

348

El Efecto De Los Atentados Del 11-s Sobre El Turismo En España  

Microsoft Academic Search

El objetivo del trabajo es analizar las consecuencias que los atentados del 11-S han tenido sobre los flujos turísticos en España. El marco teórico utilizado se inspira en el modelo del comportamiento racional del consumidor desarrollado por Enders et al. (1992), en el se incluye el estudio de los efectos del terrorismo sobre la actividad del sector turístico. El estudio

BERNARDÍ CABRER BORRÁS; DAVID IRANZO PÉREZ

2007-01-01

349

Arquitectura del Sistema de Gestin del ancho de Banda y Proteccin (SGBP) para entornos de redes  

E-print Network

Arquitectura del Sistema de Gestión del ancho de Banda y Protección (SGBP) para entornos de redes de banda y protección para entornos de redes MPLS. El sistema está formado por dos módulos, el de de banda. 1. Introducción La evolución de las tecnologías de las comunicaciones hacia redes de

Ortega, Eusebi Calle

350

COMPORTAMENT DEL PAS DEL CAMPUS DE LA UIB, EN REFERNCIA A LA MOBILITAT  

E-print Network

PARTICIPACI� VA SER MOLT ELEVADA 2. LA MILLORA DE LA CARRETERA, L'AVARIA DEL METRO EL CURS 2007-2008 I L; 39,9% Bus, Metro; 24; 16,8% Bus, Metro, Tren; 1; 0,7% Metro; 36; 25,2% Metro, Tren; 21; 14,7% Taxi, Metro, Bus; 1; 0,7% Taxi, Tren, Metro, Bus; 1; 0,7% Tren; 2; 1,4% ·Veient l'absurd dels resultats s

Oro, Daniel

351

MIQUEL DELS SANTS OLIVER EN EL 150 ANIVERSARI DEL SEU NAIXEMENT  

E-print Network

MIQUEL DELS SANTS OLIVER EN EL 150è ANIVERSARI DEL SEU NAIXEMENT (Campanet, 1864 ­ Barcelona, 1920'anàlisi de la personalitat i l'obra d'Oliver. Primerament hi haurà una jornada d'estudi, l'objectiu de la impartirà una conferència a la seu de la Societat Arqueològica Lul·liana, entitat de la qual Oliver va ser

Oro, Daniel

352

Víctimas y victimarios: Cómplices del discurso del poder en Una noche con el Sr. Magnus e hijos de Ricardo Monti  

E-print Network

FALL 1989 37 Víctimas y victimarios: Cómplices del discurso del poder en Una noche con el Sr. Magnus e hijos de Ricardo Monti Roberto Previdi Froelich ... porque nunca podemos odiar a las personas que sabemos son capaces de hacer exactamente... en los lados ocultos que encarnan la sutil naturaleza de la ideología burguesa en su discurso del poder. Si bien presenciamos una evidente ruptura con una construcción tradicional del realismo teatral,1 el teatro de Monti, a través de sus...

Previdi Froelich, Roberto

1989-10-01

353

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.

354

Monitor de Pilates Programa del curso  

E-print Network

práctica deportiva · Lcdo. Ciencias de la Actividad Física y el Deporte · Especialista en Salud y práctica. · Revisor Científico: · Revista Andaluza Medicina Deporte · Revista PubliCE Standard (ISSN 1667-4030) y · Miembro Honor Federación Dominicana Medicina del Deporte · Galardón Nacional al Mérito Deportivo Intergyms

Escolano, Francisco

355

La evolucion del modernismo en Puerto Rico  

E-print Network

a echar raices para el 1911. La produccion modernista se recogio en las revistas Puerto Rico ilustrado (1910 hasta la actualidad) y muy en especial, en la Revista de las Antillas (1913-1914). Varios fueron los poetas que sobresalieron dentro del.... Pero su produccion no se limita a estas tres obras; Ruben Dario cultivo varios generos literarios corno lo son el cuento poematico, la prosa, la cronica, el libro de viajes y la semblanza biografica mezclada con el comentario critico (Lazo 29...

Gonzalez-Hernandez, Miriam Mercedes

1989-01-01

356

II Taller Centroamericano y del Caribe: Guatemala  

E-print Network

Ricardo 152 LATIN AMERICAN THEATRE REVIEW Mendoza, salvadoreño radicado en Costa Rica; Maquillaje, por Damián Félix, panameño y finalmente Danza Teatro por María Méndez quien trabaja en Grecia, pero está de asueto en Guatemala. Hubo diferentes paneles... fueron: Ricardo Martínez, dramaturgo y director; Ligia Méndez, actriz y promotora cultural; Fernando Meneos, actor, director y docente teatral y Guillermo Ramírez, director y productor, presidente de la Asociación Guatemalteca de Trabajadores del...

Bravo-Elizondo, Pedro

1991-10-01

357

Premio Ollantay 1989 - Acta del jurado  

E-print Network

, personas e instituciones cuyas trayectorias, dedicadas al desarrollo del teatro a nivel continental, ameriten ser destacadas como ejemplo. El Jurado designado por el CELCIT para otorgar los Premios Ollantay correspondientes al año 1989, integrado por... Colombia 2. Grupo de Teatro al Teatro Imagen, de Chile 3. Institución de Apoyo al Teatro al Consejo Nacional de Ciencia y Tecnología, CONCYTEC, de Perú 4. Teatro Infantil al Grupo de Teatro de Muñecos "Quijotillo," de Cumaná, Venezuela 5. Publicación...

Editors

1990-04-01

358

El uso de la neuromodulación para el tratamiento del temblor  

PubMed Central

Introducción: El temblor puede ser un desorden incapacitante y el tratamiento de primera línea para estos pacientes es farmacológico. Sin embargo, este tratamiento puede llevar a una reducción satisfactoria del temblor en sólo el 50% de los pacientes con temblor esencial. La talamotomía era el tratamiento de elección para el temblor refractario al tratamiento médico hasta que comenzó a utilizarse la estimulación cerebral profunda (ECP) del núcleo ventral intermedio (Vim) del tálamo. En la actualidad, raramente se realiza la talamotomía. Métodos: Este artículo es una revisión no sistemática de las indicaciones, resultados, parámetros de programación y técnica quirúrgica de la ECP del Vim para el tratamiento del temblor. Resultados: Aunque los resultados clínicos son similares usando la talamotomía o la ECP del Vim, la primera causa más efectos adversos que la última. Además, la ECP puede ser usada bilateralmente, mientras que la talamotomía tiene un alto riesgo de causar disartria cuando se realiza de ambos lados. La ECP del Vim logró una adecuada mejoría del temblor en varias series de pacientes con temblor causado por temblor esencial, enfermedad de Parkinson o esclerosis múltiple. Además del Vim, hay otros blancos que están siendo usados por varios autores, tales como la zona incerta y las radiaciones prelemniscales. Conclusión: La ECP del Vim es un tratamiento útil para el temblor incapacitante refractario al tratamiento médico. Es esencial realizar una precisa selección de pacientes, así como utilizar una técnica quirúrgica correcta. Aún se desconoce el mejor blanco estereotáctico para el temblor, aunque el Vim es el más usado. PMID:25165613

Bendersky, Damián; Ajler, Pablo; Yampolsky, Claudio

2014-01-01

359

Morphology, geology and geochemistry of the "Salar del Gran Bajo del Gualicho" (Rio Negro, Argentina)  

USGS Publications Warehouse

A multidisciplinary study of the Gran Bajo del Gualicho area (Rio Negro - Argentina) was carried out; the aim was to delineate its geological and geomorphological evolution and to estabilish the genesis of salts filling the depression. Climatic conditions were analized first to individuate their role in the present morphogenetic processes; moreover the main morphological features of present landscape were examined as well as the stratigraphy of the outcropping formations, and of the Gran Bajo del Gualicho Formation in particular. Finally, a possible geomorphological evolution of the studied area was traced. Geophysical analyses allowed to estabilish that the paleosurface shaped on the crystalline basement is strongly uneven and shows evidence of the strong tectonic phases it underwent. The result of isotope analyses confirmed that the salt deposits on the Gran Bajo del Gualicho bottom were produced by fresh water evaporation, while strontium isotope ratio suggested that such waters were responsible for solubilization of more ancient evaporitic deposits.

Angelucci, A.; Barbieri, M.; Brodtkorb, A.; Ciccacci, S.; Civitelli, G.; De Barrio, R.; Di, Filippo M.; Fredi, P.; Friedman, I.; Lombardi, S.; Schalamuk, A.I.; Toro, B.

1996-01-01

360

Influencia del talento del empresario y del tipo de página web en los resultados empresariales para las casas de turismo rural en España  

Microsoft Academic Search

El Turismo rural ha alcanzado un auge muy fuerte en España e internet se ha convertido en una herramienta vital en el sector. En este trabajo se persigue: 1) analizar la importancia del talento del empresario en la implantación de páginas web; 2) examinar la influencia de este talento y de las características de la página web sobre los resultados

Jannine Waleska; Nieto Arias; Rosa María; Hernández Maestro; Pablo A. Muñoz Gallego

361

Propuesta metodológica para la evaluación del impacto de la contaminación de las cuencas hídricas del país: Estudio de caso del río “La vieja”  

Microsoft Academic Search

El presente estudio estuvo enfocado en la generación de una metodología general dirigida a cuantificar el impacto socioeconómico de la contaminación de las cuencas hídricas tomando como caso particular la Cuenca del Río La Vieja y a la población de Cartago (Valle del Cauca). Los tópicos desarrollados en este trabajo de investigación se pueden resumir en los siguientes aspectos: En

Alfredo SARMIENTO; Darwin Marcelo GORDILLO; Juan Miguel VILLA

2005-01-01

362

UNIVERSIDAD NACIONAL AUTNOMA DE MXICO Datos del plan de estudio  

E-print Network

Pruebas de Evaluación Psicológica en el Deporte Dirigido a: Entrenadores de la DGADyR, Comunidad el psicólogo del deporte debe obtener los índices del estado psicológico de los deportistas, lo que así como las técnicas utilizadas en psicología del deporte para modelar las características

Islas, León

363

La profesionalización del teatro nacional argentino. Un precursor: Nemesio Trejo  

E-print Network

acuerdo a las ineludibles reglas del mercado que el incipiente capitalismo había impuesto en la economía argentina. Los productores del mensaje teatral pertenecían en su mayoría a esa nueva promoción de escritores profesionalizados, provenientes de las.... Estas dos profesiones fueron asumidas en su vida con pasión y consciente de "la flagrante evidencia de la nueva economía de la época finisecular: la instauración del mercado," como apunta acertadamente Ángel Rama acerca de los poetas modernistas (1...

Pellarolo, Silvia

1997-10-01

364

El Sexto Festival de Teatro Español del Siglo de Oro  

E-print Network

SPRING 1981 79 El Sexto Festival de Teatro Español del Siglo de Oro Arturo Pérez-Pisonero El Sexto Festival de Teatro Español del Siglo de Oro, celebrado en el Chamizal National Memorial en las fechas del 6 al 22 de marzo, ha presen tado, como... en años anteriores, un muy variado programa de grupos profe sionales y aficionados. La nutrida participación ha demostrado, en muchos casos, más entusiasmo que habilidad por parte de directores y actores para resolver la compleja problemática que...

Pé rez-Pisonero, Arturo

1981-04-01

365

La generación de 1924: El dilema del realismo  

E-print Network

preocupaciones existenciales visibles en la poesía del autor: la autenticidad individual, la relatividad, el dilema solipsista. Lo fascinante es que las dos obras están concebidas dentro del teatro realista; son como variantes a la temática consabida del lío...) da el paso definitivo. Se emplean máscaras y un prólogo hablado directamente al público, predominan las escenas de dos personajes y en general una estructura que recuerda la de la tragedia griega. Porque de eso se trata: Cuauhtemoc es una...

Dauster, Frank

1985-04-01

366

DERECHOS DEL EMPLEADO LEy PARA LA PROtECCin  

E-print Network

DERECHOS DEL EMPLEADO LEy PARA LA PROtECCión DEL EMPLEADO COntRA LA PRuEbA DEL POLígRAfO PROHIBICIONES ExENCIONES DERECHOS DE LOS ExAMINADOS CUMPLIMIENTO Generalmente se le prohíbe al empleador que le aspirante a un trabajo por haberse negado a someterse a la prueba o por haberse acogido a otros derechos

Rock, Chris

367

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.

368

Efecto del Programa de Entrenamiento “Manejo del Dolor” en la Documentación de Enfermería en el Expediente Electrónico  

PubMed Central

Resumen En el presente trabajo se muestra la importancia de entrenar al personal de enfermería para mejorar la documentación en el expediente electrónico. Se eligió el manejo del dolor por ser un área prioritaria; una alta proporción de pacientes en período post operatorio cursa con dolor, por lo tanto, la documentación debe ser útil para la toma de decisiones clínicas. Se implementó un programa de entrenamiento denominado “Manejo del Dolor” dirigido al personal de enfermería. Se utilizó la tecnología de la información como herramienta para fortalecer el conocimiento con base en la revisión sistemática de la literatura; el personal de enfermería participante seleccionó la mejor evidencia; posteriormente se trabajó en la transferencia de este conocimiento a la práctica a través del diseño de un protocolo para el manejo del dolor. Se concluye que el conocimiento del manejo del dolor es fundamental para que enfermería documente con mayor precisión sus intervenciones. PMID:24199106

Monsiváis, María Guadalupe Moreno; Guzmán, Ma. Guadalupe Interial; Flores, Paz Francisco Sauceda; Arreola, Leticia Vázquez

2012-01-01

369

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

370

RELACIÓN MÉDICO PACIENTE: DERECHOS DEL ADULTO MAYOR  

PubMed Central

Existen prejuicios en relación con la vejez, incluso entre los profesionales que se dedican a la gerontología. Uno común y peligroso es considerar que los viejos son todos enfermos o discapacitados. La relación médico-paciente es la piedra angular de la práctica y ética médicas. Para alcanzar el respeto por los adultos mayores es necesaria una medicina prudente, basada en una práctica en la cual la reflexión ética y clínica pueda contribuir. Esto último es posible si se hacen valer los derechos del adulto mayor, en particular como paciente para la toma de decisiones. PMID:20379380

Barrantes-Monge, Melba; Rodríguez, Eduardo; Lama, Alexis

2009-01-01

371

Eficiencia y determinantes del funcionamiento del mercado paralelo de divisas en Colombia  

Microsoft Academic Search

El presente trabajo analiza la relación entre el tipo de cambio negro y el oficial, al igual que la eficiencia del mercado paralelo de divisas en Colombia. Con base en datos mensuales para el período 1970-1989, se encontró que la tasa de cambio oficial y paralela estaban cointegradas, lo cual implica que el dólar oficial y el negro mantuvieron una

Santiago Herrera

1990-01-01

372

¿Puede la escuela del siglo XXI educar a los ciudadanos y ciudadanas del siglo XXI?  

Microsoft Academic Search

Los graves problemas de nuestro mundo reclaman una urgente respuesta educativa por parte del sistema escolar, pero esa respuesta no es adecuada, pues dicho sistema sigue funcionando con características muy tradicionales. La educación para la ciudadanía se presenta como una posibilidad de reorientar la educación hacia finalidades más acordes con los retos que ésta debe afrontar actualmente; sin embargo, entre

Francisco F. García Pérez; Nicolás de Alba Fernández

2008-01-01

373

Determinantes del Gasto Público en Educación y Resultados del sistema educativo por Comunidades Autónomas  

Microsoft Academic Search

RESUMEN Este trabajo tiene como objetivo analizar el gasto público en educación y sus principales determinantes por Comunidades Autónomas durante el período 2000-2004. Al mismo tiempo, trata de analizar la incidencia del mismo en términos de los resultados obtenidos por el sistema educativo en las distintas Comunidades Autónomas. ABSTRACT This paper analyzes the regional public spending in education during 2000-2004

Alfonso Utrilla de la Hoz; Carmen Mitxelena Camiruaga

2007-01-01

374

ALGORITMOS DE OPTIMIZACIN APLICADOS AL SEGUIMIENTO DEL MOVIMIENTO ARTICULAR Y LA DIGITALIZACIN AUTOMTICA DEL  

E-print Network

de imágenes es una tarea compleja que supone un alto coste computacional. Este tipo de objetos los estimados, adaptando el coste computacional a los requisitos del problema en cada momento y necesaria para definir la pdf y, por tanto, el alto coste computacional que conlleva

Pantrigo Fernández, Juan José

375

Estudios Geol., 59: 133-144 (2003) REGISTRO DE LOS CAMBIOS DEL NIVEL DEL MAR DURANTE  

E-print Network

EN LAS ISLAS CANARIAS OCCIDENTALES (TENERIFE Y LA PALMA) C. Zazo*, J. L. Goy**, C. Hillaire Tenerife, y consiste en cinco terrazas marinas localizadas entre los O y 18 m (por encima del nivel medio.000 años, sugieren una ligera ten- dencia al hundimiento en la isla de Tenerife y un ligero levantamiento

Long, Bernard

376

FISH and SNP-A karyotyping in myelodysplastic syndromes: improving cytogenetic detection of del(5q), monosomy 7, del(7q), trisomy 8 and del(20q).  

PubMed

Cytogenetic aberrations identified by metaphase cytogenetics (MC) have important diagnostic, prognostic and therapeutic roles in myelodysplastic syndromes (MDS). Fluorescence in situ hybridization (FISH) complements MC by the ability to evaluate large numbers of both interphase and metaphase nuclei. However, clinically practical FISH strategies are limited to detection of known lesions. Single nucleotide polymorphism array (SNP-A)-based karyotyping can reveal unbalanced defects with superior resolution over MC and FISH and identify segmental uniparental disomy (UPD) undetectable by either method. Using a standardized approach, we focused our investigation on detection of -5/del(5q), -7/del(7q), trisomy 8 and del(20q) in patients with MDS (N=52), MDS/myeloproliferative overlap syndromes (N=7) and acute myeloid leukemia (N=15) using MC, FISH and SNP-A karyotyping. The detection rate for del(5q) was 30, 32 and 32% by MC, FISH, and SNP-A, respectively. No single method detected all defects, and detection rates improved when all methods were used. The rate for detection of del(5q) increased incrementally to 35% (MC+FISH), 38% (MC+SNP-A), 38% (FISH+SNP-A) and 39% (all three methods). Similar findings were observed for -7/del(7q), trisomy 8 and -20/del(20q). We conclude that MC, FISH and SNP-A are complementary techniques that, when applied and interpreted together, can improve the diagnostic yield for identifying genetic lesions in MDS and contribute to the better description of abnormal karyotypes. PMID:19758696

Makishima, Hideki; Rataul, Manjot; Gondek, Lukasz P; Huh, Jungwon; Cook, James R; Theil, Karl S; Sekeres, Mikkael A; Kuczkowski, Elizabeth; O'Keefe, Christine; Maciejewski, Jaroslaw P

2010-04-01

377

Instantánea de los cánceres de cerebro y del sistema nervioso central  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre los cánceres de cerebro y del sistema nervioso central; así como ejemplos de actividades del NCI y adelantos en la investigación de estos tipos de cáncer.

378

Ciclo de vida del VIH Enlace y fusin: El VIH empieza su ciclo de vida  

E-print Network

inversa convierte la cadena simple del ARN vírico en cadena doble de ADN vírico. Integración: El nuevo ADN integrasa "esconde" el ADN vírico dentro del propio ADN de la célula anfitriona. El ADN del VIH integrado se­800­448­0440. En Internet www.aidsinfo.nih.gov/infoSIDA. mayo del 2005 1 Human DNA HIV DNA ARN del VIH ADN del VIH

Levin, Judith G.

379

Del carnaval como 'metáfora' al teatro de carnaval  

E-print Network

particular, al tema de la fiesta, del carnaval y del caníbal en la literatura y el teatro. Esta preocupación se relaciona, a su vez, con el desarrollo de un diálogo entre el teatro y la antropología, en torno a los dramas sociales, las formas orales o no...

Remedi, Gustavo

2001-04-01

380

La vulnerabilidad fiscal del gasto social: ¿Es Diferente América Latina?  

Microsoft Academic Search

Se utiliza un panel desbalanceado de medio centenar de países para el período 1985-2003 con el objeto de evaluar la vulnerabilidad del gasto público social (en educación y salud) frente a las variables fiscales corrientes y la deuda pública en América Latina en comparación con el resto del mundo en desarrollo. El gasto social es significativamente más bajo en América

Eduardo Lora

2007-01-01

381

Regalías y finanzas públicas en el Departamento del Cesar  

Microsoft Academic Search

Como resultado de las explotaciones de carbón en el Cesar en los últimos años, se han generado importantes recursos de regalías y compensaciones que afectan las finanzas públicas del gobierno departamental. El propósito de este documento es analizar esta relación y proyectar los ingresos y gastos del gobierno departamental para el período 2007 – 2017. Las proyecciones muestran que una

Jaime Bonet Morón

2007-01-01

382

Decoding F508del Misfolding in Cystic Fibrosis  

PubMed Central

The functional deficiency of the cystic fibrosis transmembrane conductance regulator (CFTR), a plasma membrane chloride channel, leads to the development of cystic fibrosis. The deletion of a phenylalanine at residue 508 (F508del) is the most common cause of CFTR misfolding leading to the disease. The F508del misfolding originates in the first nucleotide-binding domain (NBD1), which induces a global conformational change in CFTR through NBD1’s interactions with other domains. Such global misfolding produces a mutant chloride channel that is impaired in exocytic trafficking, peripheral stability, and channel gating. The nature and atomic details of F508del misfolding have been subject to extensive research during the past decade. Current data support a central role for NBD1 in F508del misfolding and rescue. Many cis-acting NBD1 second-site mutations rescue F508del misfolding in the context of full-length CFTR. While some of these mutations appear to specifically counteract the F508del-induced misfolding, others release certain inherent conformational constraints of the human wild-type CFTR. Several small-molecule correctors were recently found to act on key interdomain interfaces of F508del CFTR. Potential rational approaches have been proposed in an attempt to develop highly effective small molecule modulators that improve the cell surface functional expression of F508del CFTR. PMID:24970227

Wang, Xiaodong Robert; Li, Chenglong

2014-01-01

383

CIENCIA, TECNOLOGA, POLTICA Y PLANIFICACIN DEL AGUA Y DE  

E-print Network

de lluvia, reutilización... Adicionalmente al uso del agua y a pesar de que tenemos cada vez unassegunda circular enero 2011 CIENCIA, TECNOLOGÍA, POLÍTICA Y PLANIFICACI�N DEL AGUA Y DE LA ENERGÍA EN LOS REGADÍOS. ASPECTOS SOCIOEC�NOMICOS Y AMBIENTALES. AGRICULTURA, AGUA Y ENERGÍA colaboran MADRID

Escolano, Francisco

384

Los Derechos de los Pacientes del Centro Clnico  

E-print Network

Los Derechos de los Pacientes del Centro Clínico Los Derechos de los Pacientes del Centro Clínico medir las respuestas de los pacientes al tratamiento. Existen procesos que protegen los derechos de paciente que se observen los derechos fundamentales de la dignidad humana. Esta Declaración de Derechos

385

El presidente Obama anuncia nombramiento del doctor Harold Varmus  

Cancer.gov

En los últimos cinco años como director del NCI, y en otras funciones ejercidas durante muchos años, he disfrutado ampliamente cada oportunidad que he tenido de visitar los laboratorios y las oficinas, desde Bethesda hasta Frederick, para conocer en persona a los miembros del personal y compartir mis opiniones sobre temas importantes en torno a la ciencia y al manejo de este gran Instituto.

386

El Instituto Nacional del Cáncer de EE. UU. y la República del Perú firman una Declaración de Intención  

Cancer.gov

El Instituto Nacional del Cáncer y la República del Perú firmaron una declaración de intención para compartir el interés en fomentar la investigación biomédica de oncología, basándose en la colaboración mutua de ambas entidades, así como el objetivo común de educar y capacitar la futura generación de científicos y clínicos en investigación oncológica.

387

Influencia del viento en el comportamiento de búsqueda del alimento en un grupo de aves insectívoras forestales  

Microsoft Academic Search

Carrascal, L.M, 1986. Influencia del viento en el comportamiento de búsqueda del alimento en un grupo de aves insectívoras forestales. Misc. Zool., 10: 277-285. Influence of wind on the foraging behaviour of a guild of arboreal insectivorous birds.- This work was carried away in a subalpine coniferous forest in Central Spain. Wind shifts the birds to the soil and to

L. M. Carrascal

2008-01-01

388

Declaración del Instituto Nacional del Cáncer sobre la aprobación de la vacuna de VPH por la FDA  

Cancer.gov

Hace casi dos décadas que los investigadores del NCI y de otras instituciones comenzaron a investigar las causas fundamentales del cáncer cervical. Esta búsqueda científica resultó en la aprobación de hoy de la vacuna GardasilTM por la Food and Drug Administration.

389

Ttulo del Trabajo: Acerca del estilo de pensamiento en los inicios de la Historia de la Ciencia en la Argentina  

E-print Network

1 Título del Trabajo: Acerca del estilo de pensamiento en los inicios de la Historia de la Ciencia Nacional de Río Cuarto. Facultad de Ciencias Humanas y Facultad de Ciencias Exactas, Físico ­ Químicas y Naturales. Introducción: Una mirada a las actas de las Jornadas de Historias de la Ciencia Argentina (2003

Paris-Sud XI, Université de

390

La guerra del fin del mundo: historia e invencion en una novela historica  

E-print Network

multiplicidad de perspectives Galileo Gall: La ciencia y la revolucion versus el misterio religioso y la realidad sertanera El periodista miope: El testigo ocular y la vocacion del escritor El Baron de Canabrava: El comentario, fanaticos y fracasados 39... para una representacion adecuada de esa "verdad" (traducido de White, 23-24). Pero ". . . [en] la epoca contemporanea el afan critico y cienti- fico extrae a la Historia de la Literature, la convierte en una ciencia, y la entiende desvinculada...

Loeffler, Lisa Bowe

1984-01-01

391

rea de Actividad Fsica y Salud 445 EVALUACIN ERGONMICA DEL PUPITRE  

E-print Network

del Deporte. Universidad de Extremadura RESUMEN Los alumnos de la Facultad de Ciencias del Deporte de los #12;446 I CONGRESO DE LA ASOCIACIÃ?N ESPAÃ?OLA DE CIENCIAS DEL DEPORTE responsables de compra se partiendo de las quejas de los alumnos de la Facultad de Ciencias del Deporte de la Universidad de

Pantrigo Fernández, Juan José

392

Doctor Harold Varmus, director del NCI: Bienvenidos a Cancer.gov en español  

Cancer.gov

El director del NCI, doctor Harold Varmus, da la bienvenida a los visitantes al sitio web del NCI y habla sobre la complejidad del cáncer, así como de los avances alcanzados gracias a las nuevas herramientas y tecnologías para la investigación del cáncer.

393

Diagnóstico del sector deporte, la recreación y la educación física en Antioquia  

Microsoft Academic Search

En general, podemos resumir este proyecto en tres grandes productos que permiten contextualizar, proponer y desarrollar una política pública a favor del deporte, la educación física y la recreación en Antioquia, que denominaremos en adelante el Sector Deportivo Antioqueño –SDA-. El primero de estos productos es la realización de un diagnóstico del SDA que de cuenta del estado del arte

Ramón Javier Mesa Callejas; Rodrigo Arboleda Sierra; Juan Francisco Gutiérrez Betancur; Mauricio López González

2006-01-01

394

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

395

Universidad Nacional Autnoma de Mxico Instituto de Ciencias del Mar y Limnologa  

E-print Network

Universidad Nacional Autónoma de México Instituto de Ciencias del Mar y Limnología Informe de Instituto de Ciencias del Mar y Limnología Fundamento Legal · Legislación Universitaria · Estatuto General;Informe de actividades 2011 - 2012 Instituto de Ciencias del Mar y Limnología Instituto de Ciencias del

Islas, León

396

Decreto n. 11/10 Il Direttore del Dipartimento di Fisica  

E-print Network

Decreto n. 11/10 Il Direttore del Dipartimento di Fisica Visto il Regolamento relativo al in data 26/11/2007; Vista la delibera del Consiglio del Dipartimento di Fisica del 16/09/2009; Vista la Dipartimento di Fisica per il programma di ricerca dal titolo"Studio di Cosmologia e Fisica Fondamentale dello

Guidoni, Leonardo

397

Decreto n. 10/10 Il Direttore del Dipartimento di Fisica  

E-print Network

Decreto n. 10/10 Il Direttore del Dipartimento di Fisica Visto il Regolamento relativo al in data 26/11/2007; Vista la delibera del Consiglio del Dipartimento di Fisica del 16/09/2009; Vista la Dipartimento di Fisica per il programma di ricerca dal titolo"Studio di Cosmologia e Fisica Fondamentale dello

Guidoni, Leonardo

398

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.

399

Modular cell biology: retroactivity and insulation Domitilla Del Vecchio1,  

E-print Network

Modular cell biology: retroactivity and insulation Domitilla Del Vecchio1, *, Alexander J Ninfa2 a remarkable insulation property, due to the fast timescales of the phosphorylation and dephosphorylation: computational methods; metabolic and regulatory networks Keywords: feedback; insulation; modularity; singular

Sontag, Eduardo

400

La Revolucin del Shale Gas Profesor: Hugh Rudnick  

E-print Network

La Revolución del Shale Gas Mayo 2011 Profesor: Hugh Rudnick Profesional Externo: Verónica Cortés........................................................................................................................................ 6 ¿Qué es el Shale Gas...................................................................................................................................... 7 Shale Gas

Rudnick, Hugh

401

Particle Methods for Filtering & Uncertainty Propagations P. Del Moral  

E-print Network

, ... · Physics (sensors : pressure/temperature/...). · Finance (assets, portfolios,...). · Statistics (real dataParticle Methods for Filtering & Uncertainty Propagations P. Del Moral INRIA team ALEA, INRIA, pressure/temperature/diffusion coefficients,...). · Finance (assets, portfolios, volatilities, default

Del Moral , Pierre

402

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

403

UNIVERSIDAD NACIONAL AUTNOMA DE MXICO Datos del plan de estudio  

E-print Network

Síntesis o descripción breve: Se atienden las vertientes propias de las ciencias aplicadas al deporte para · La Actividad Física y el Deporte · Nutrición en el Deporte · Psicología del Adolescente Módulo II Entrenamiento Deportivo · Psicología del Deporte · Formación Docente · Recreación en el Deporte · Taller de

Islas, León

404

Calidad del aire interior y salud en las viviendas  

E-print Network

Calidad del aire interior y salud en las viviendas temporales de FEMA A los residentes de los que usted pueda tener sobre la calidad del aire y el formaldehído en los tráileres de FEMA. Usted pequeños, como los tráileres de FEMA, los venenos para matar insectos también pueden irritar l a nariz o la

405

Jornada d'ensenyament i s del valenci als  

E-print Network

Jornada d'ensenyament i ús del valencià als centres educatius 2014 Intercanvi d'experiències d'educació plurilingüe. ALACANT, 5 de juny de 2014 Lloc de realització: Universitat d'Alacant #12;Jornada d'ensenyament i ús del valencià als centres educatius 2014 Intercanvi d'experiències d'educació plurilingüe En un

Escolano, Francisco

406

Design, aerodynamics and autonomy of the DelFly  

Microsoft Academic Search

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

G C H E de Croon; M A Groen; C De Wagter; B Remes; R Ruijsink; B W van Oudheusden

2012-01-01

407

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

408

Miami: Meca del exilio cubano y escenario medido aunque efervescente  

E-print Network

Agüero, Raúl Duran y David Ferrer, logrando niveles intertextuales muy ricos pues cada movimiento, cada signo básico, cada inflexión verbal, encontró correspondencias afínes en la comunidad cubana del exilio para la que se representó, fuera de que... del autor como Jesús, bajo la dirección de Rolando Moreno, estrenada en 1994. A esta última obra se le dio un tratamiento musical que no desentonó con el tema de la misma y reafirmó el gusto ya estudiado en otra ocasión de esta comunidad por el...

Rizk, Beatriz J.

2000-10-01

409

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

410

Rompimiento de la Simetria Electrodebil y la Fisica del Higgs: Conceptos Basicos  

E-print Network

Presentamos una introduccion a los conceptos basicos del rompimiento de la simetria electrodebil y la fisica del Higgs dentro del Modelo Estandar y sus extensiones supersimetricas. Se presenta tambien una breve perspectiva general de mecanismos alternativos del rompimiento de la simetria. Ademas de las bases teoricas, se discute el estado actual de la fisica experimental del Higgs y sus implicaciones para futuros experimentos en el LHC y en colisionadores lineales e+e-.

M. Gomez-Bock; M. Mondragon; M. Muhlleitner; R. Noriega-Papaqui; I. Pedraza; M. Spira; P. M. Zerwas

2005-09-08

411

Assicurativo | Bancario | Finanziario Allianz SpA ai primi posti del mercato italiano delle assicurazioni e dei servizi finanziari e fa parte del  

E-print Network

italiano delle assicurazioni e dei servizi finanziari e fa parte del Gruppo Allianz SE, il leader confermata ai vertici del mercato italiano in termini di solidità patri- moniale con il solvency ratio e i

Schettini, Raimondo

412

XI Muestra Nacional de Teatro Peruano y I Encuentro Interregional de Teatro Peruano del Movimiento de Teatro Independiente del Perú  

E-print Network

considerar que Cusco es un "pueblo testimonio" del choque de dos culturas de alta civilización y nombrado por la ONU Patrimonio Mundial de la historia de la humanidad. MOTIN-CUSCO amplió la programación para paralelamente realizar la I Muestra...

Ferguson Acosta, Dennis

1993-10-01

413

Línea de base del Proyecto de producción ecológica, comercialización y asociatividad de las mujeres en el medio rural: Manual del sistema de monitoreo y seguimiento  

Microsoft Academic Search

El Sistema de monitoreo y seguimiento ha sido elaborado especialmente para la organización En las Huellas del Banco Grameen-Loja, cuyo propósito es facilitar el acceso a servicios financieros y técnicos eficientes y sostenibles para mujeres microempresarias del sur ecuatoriano. El manual fue diseñado como un instrumento que sirva de guía para que la dirección ejecutiva y la coordinación del Proyecto

Carlos Palán Tamayo

2009-01-01

414

LAS CLASES SE IMPARTIRN EN EL AULA 057, PLANTA BAJA DEL EDIFICIO DEPARTAMENTAL, CAMPUS DE 2013 Horarios Mster en Gestin del Transporte y la Movilidad -Primer cuatrimestre  

E-print Network

VICÁLVARO 2013 Horarios Máster en Gestión del Transporte y la Movilidad - Primer cuatrimestre SEPTIEMBRE 16 sistemas de transporte Infraestructuras de la movilidad Jueves 19 Organización y financiación del transp transporte Infraestructuras de la movilidad Jueves 26 Organización y financiación del transp. Economía

Rey Juan Carlos, Universidad

415

Poich il28 Ottobre prevista alla stessa ora l'Assemblea Generale del Personale nell'Androne Principale del Policlinico Umberto I  

E-print Network

'Androne Principale del Policlinico Umberto I: E' convocata la Riunione di tutti i componenti della R.S.U. per Policlinico Umberto I; 5) Situazione Personale del Policlinico Umberto I; 6) Progetti obiettivi: attività in regime di straordinario (Policlinico Umberto I); 7) Ipotesi di dotazione organica per il personale del

Guidoni, Leonardo

416

Modelo semi-empírico de protuberancia solar a partir del diagnóstico de densidades  

NASA Astrophysics Data System (ADS)

A partir de la observación del espectro del quintuplete de C III alrededor de 1175 Å, se ha realizado el diagnóstico de la densidad y presión electrónica, basado en el cálculo del cociente de las intensidades observadas. Una vez establecida la densidad electrónica, y con el cálculo de las velocidades Doppler, hemos investigado el flujo de masa en la protuberancia en función de la temperatura. Estableciendo como hipótesis la conservación del número de partículas que ingresan y salen del cuerpo de la protuberancia, se investiga la variación del área de un tubo de flujo semi-empírico en función de la temperatura. A partir de dicho diagnóstico, se examina el comportamiento del radio del tubo magnético en función de la temperatura, los que dan cuenta de la abertura de las líneas de campo magnético que confinan el plasma y de la divergencia del campo magnético en diferentes alturas de la atmósfera solar.

Cirigliano, D.; Vial, J. C.; Rovira, M.

417

RISULTATI VALUTAZIONE TITOLI DEL CONCORSO PER L'ASSEGNAZIONE DI N.1 ASSEGNO DI RICERCA PROG. DI RICERCA N. 11.05 BANDITO CON D.R. N.2285 DEL 3.6.2013  

E-print Network

, piazza Umberto I, 1, Bari. Visto l'art. 8 del D.R. n. 2285 DEL 3.6.2013, che prevede l, piazza Umberto I, 1, Bari. Visto l'art. 8 del D.R. n. 2285 DEL 3.6.2013, che prevede l, piazza Umberto I, 1, Bari. #12;3 Visto l'art. 8 del D.R. n. 2285 DEL 3.6.2013, che prevede l

Malerba, Donato

418

Field measurements of del13C in ecosystem respiration  

NASA Astrophysics Data System (ADS)

Stable carbon isotope del13C-measurements are extensively used to study ecological and biogeochemical processes in ecosystems. Above terrestrial ecosystems, atmospheric del13C can vary largely due to photosynthetic fractionation. Photosynthetic processes prefer the uptake of the lighter isotope 12C (in CO2), thereby enriching the atmosphere in 13C and depleting the ecosystem carbon. At night, when ecosystem respiratory fluxes are dominant, 13C-depleted CO2 is respired and thereby depletes the atmospheric del13C-content. Different ecosystems and different parts of one ecosystem (type of plant, leaves, and roots) fractionate and respire with a different del13C-ratio signature. By determining the del13C-signature of ecosystem respiration in temporal and spatial scale, an analysis can be made of the composition of respiratory sources of the ecosystem. A field study at a dry cropland after harvest (province of Viterbo, Lazio, Italy) was performed in the summer of 2013. A FTIR (Fourier Transform Infrared Spectrometer) was set up to continuously measure CO2-, CH4-, N2O-, CO- and del13C-concentrations. The FTIR was connected to 2 different flux measurements systems: a Flux Gradient system (sampling every half hour at 1.3m and 4.2m) and 2 flux chambers (measured every hour), providing a continuous data set of the biosphere-atmosphere gas fluxes and of the gas concentrations at different heights. Keeling plot intercept values of respiratory CO2, measured by the Flux Gradient system at night, were determined to be between -25‰ and -20‰. Keeling plot intercept values of respiratory CO2, measured by the flux chamber system, varied between -24‰ and -29‰, and showed a clear diurnal pattern, suggesting different (dominant) respiratory processes between day and night.

van Asperen, Hella; Sabbatini, Simone; Nicolini, Giacomo; Warneke, Thorsten; Papale, Dario; Notholt, Justus

2014-05-01

419

La nostalgia del paraíso en Un hogar sólido  

E-print Network

de la túnica de un ángel" (26); para Eva, una "centella que se hunde en el mar negro" (27); para Clemente "una partícula de la piedra de San Pedro" (26) o "la lluvia sobre el agua" (27); para Gertrudis, "leño en llamas" (27); para Jesusita, "el... como en otras tradiciones religiosas, este sitio está íntegramente ligado a las aguas o ríos primordiales (Partin 184). A modo de ejemplo, citamos del libro del Génesis de la Biblia, el cual también evoca la imagen de la intersección de cuatro líneas...

Anderson, Robert K.

2001-04-01

420

I Taller Internacional del Nuevo Teatro (Cuba 1983)  

E-print Network

-tease lo ejecutan y componen hombres, el acto de la cuerda floja se hace por debajo de la cuerda, al cantante popular no se le entiende la letra, etc. Esta contradicción del sentido en la formación de las imágenes viene a realzar la diferencia que existe... relación entre ellos. "Esto debe crear una reflexión del trabajo y en la medida de lo posible debe llevarse al campo de la teoría. Este taller se desarrolla en este espíritu de investigación cuyos resultados vamos a ver. No con el 78 LATIN AMERICAN...

Rizk, Beatriz J.

1983-04-01

421

La consagración del mito en la epopeya mexicana: La Malinche de Celestino Gorostiza  

E-print Network

FALL 1985 33 La consagración del mito en la epopeya mexicana: La Malinche de Celestino Gorostiza Isis Quinteros Los estudiosos del drama como género literario han señalado en varias ocasiones la estrecha relación que históricamente ha vinculado...

Quinteros, Isis

1985-10-01

422

Denaturazione termica e meccanica del DNA : teoria a confronto con gli  

E-print Network

Capitolo 3 Denaturazione termica e meccanica del DNA : teoria a confronto con gli esperimenti. DENATURAZIONE TERMICA E MECCANICA DEL DNA : TEORIA A CONFRONTO CON GLI ESPERIMENTI della transizione DNA B-DNA d

Cocco, Simona

423

33 CFR 162.35 - Channel of Christina River, Del.; navigation.  

Code of Federal Regulations, 2014 CFR

...Navigable Waters 2 2014-07-01 2014-07-01 false Channel of Christina River, Del.; navigation. 162.35 Section...SAFETY INLAND WATERWAYS NAVIGATION REGULATIONS § 162.35 Channel of Christina River, Del.; navigation. (a) That...

2014-07-01

424

El té y la prevención del cáncer: Solidez y límites de la evidencia científica  

Cancer.gov

Hoja informativa que resume los resultados de estudios realizados sobre el té y la prevención del cáncer. Incluye información sobre los ingredientes del té y las consideraciones de seguridad sobre el consumo de esta bebida.

425

El sexagésimo aniversario del Teatro Experimental de la Universidad de Chile  

E-print Network

SPRING 2001 189 El sexagésimo aniversario del Teatro Experimental de la Universidad de Chile Domingo Piga Desde antes de la primera función y de la creación del Teatro Experimental, cuando sólo nos movía la pasión por el teatro, nosotros, los...

Piga, Domingo

2001-04-01

426

El doctor Varmus dirigirá una institución "inigualable", afirma el director del NCI, doctor John Niederhuber  

Cancer.gov

En un mensaje dirigido al personal del Instituto Nacional del Cáncer (NCI) y a quienes se interesan por la oncología, el doctor John Niederhuber, director del NCI, aplaude el nombramiento de Harold Varmus y afirma que esta designación le "dará al NCI un liderazgo fuerte no solo en la institución sino mas allá de ella, así como una voz muy respetada en el Congreso, que abogue por los recursos que son tan necesarios para sostener la misión del Instituto.

427

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

428

Aspectos Económicos del Gobierno de Carlos Lleras Restrepo. (Colombia, 1966-1970)  

Microsoft Academic Search

El gobierno de Carlos Lleras Restrepo se destaca en la historia de Colombia por haber introducido una reforma institucional de amplias proporciones que fortaleció las bases del Estado intervencionista. Este hecho, sumado a una concepción estructuralista sobre el manejo monetario y cambiario, permitió un evidente despegue del sector exportador no tradicional y un crecimiento del PIB sin antecedentes en la

Pascual Amézquita Zárate

2010-01-01

429

Se pone en marcha el Programa de Investigación Oncológica Comunitaria (NCORP) del NCI  

Cancer.gov

El Instituto Nacional del Cáncer (NCI) ha otorgado 53 subvenciones nuevas de 5 años a investigadores de todo el país para realizar estudios clínicos multicéntricos e investigaciones sobre la prestación de cuidados oncológicos en sus comunidades. Las subvenciones se están otorgando dentro del Programa de Investigación Oncológica Comunitaria (Community Oncology Research Program, NCORP) del NCI.

430

rea de Biomecnica del Deporte Rendimiento Deportivo 209 DESARROLLO DE UNA "TOOLBOX" DE TRATAMIENTO  

E-print Network

Área de Biomecánica del Deporte ­ Rendimiento Deportivo 209 DESARROLLO DE UNA "TOOLBOX" DE_mail: kgiannik@unex.es Pantrigo, J.J. Vara Gazapo, A. Galapero, L. Facultad de Ciencias del Deporte. Universidad DE CIENCIAS DEL DEPORTE "corrompe" la señal obtenida. Así que, el procesamiento digital de señales se

Pantrigo Fernández, Juan José

431

Pautas para el monitoreo y la evaluación de proyectos del Programa de Empresariado Social  

Microsoft Academic Search

El objetivo de este documento es definir y tratar un conjunto mínimo de indicadores básicos de monitoreo y evaluación de proyectos que se deben recoger en todos o casi todos los proyectos aprobados en el marco del Programa de Empresariado Social (PES) del BID. El documento está dirigido al personal del BID y de instituciones homólogas que se dedican a

Glenn D. Westley

2003-01-01

432

Proyección del Fondo de Pensiones y Análisis de su Efecto en el Mercado Financiero  

Microsoft Academic Search

Este trabajo se compone de dos partes. La primera describe un modelo de proyección (contable en lo básico) del tamaño del Fondo de Pensiones chileno para las próximas dos décadas, y discute una proyección específica.La segunda parte discute el efecto probable que el crecimiento del Fondo tendría sobre el mercado financiero nacional. En particular, la discusión está orientada por la

Felipe Zurita

2005-01-01

433

Mercado interbancario colombiano y manejo de liquidez del Banco de la República  

Microsoft Academic Search

El documento tiene como objetivo describir algunos de los elementos fundamentales del mercado interbancario colombiano y del manejo de liquidez por parte del Banco de la República (BR). El documento explica las diferencias entre las principales operaciones en este mercado y describe los mecanismos a través de los cuales el BR suministra liquidez o recoge excesos de la misma en

Pamela cardozo Ortiz; carlos A. Huertas Campos; Julián A. Parra POlanía; Lina V. Patiño ECheverri

434

Situazione del Gufo reale in Svizzera In Svizzera il Gufo reale Bubo bubo era origina-  

E-print Network

Situazione del Gufo reale in Svizzera In Svizzera il Gufo reale Bubo bubo era origina- riamente Conservation Biology 2 Ficedula N. 40 DISPERSIONE DEI GIOVANI E MORTALITÃ? DEL GUFO REALE BUBO BUBO IN SVIZZERA Un'immagine emblematica per la conservazione del Gufo reale Bubo bubo. Le linee elettriche

Richner, Heinz

435

Gasto publico en educacion y distribucion del ingreso en el Peru  

Microsoft Academic Search

El estudio evalúa los efectos que el gasto público en educación ha tenido sobre la distribución del ingreso en el Perú. Las transferencias desde el presupuesto público son analizados revisando el destino del gasto en educación por estratos socioeconómicos, y su impacto de corto plazo en términos de la mejora del ingreso familiar y la modificación de la estructura distributiva.

José Rodríguez

1992-01-01

436

¿Gastar más o gastar mejor?: La eficiencia del gasto público en América Central y República Dominicana  

Microsoft Academic Search

El presente estudio realiza un análisis comparativo regional acerca de la eficiencia del gasto público tanto a nivel agregado como a nivel del gasto social, el gasto en educación y el gasto en salud. El trabajo busca dar respuesta a una pregunta por demás relevante para los países en desarrollo en general, a saber, si para mejorar el desempeño del

Roberto Machado

2006-01-01

437

Aportació al coneixement florístic de les Guilleries i del Collsacabra (Catalunya Oriental),II  

Microsoft Academic Search

Presentem noves dades corològiques per a la flora vascular dels massissos de les Guilleries i del Collsacabra. En total, tractem 25 tàxons que podem dividir en cinc grups: 1.- nous per a les Guilleries (Peucedanum officinale L., Senecio adonidifolius Loisel., etc.); 2.- nous pel Collsacabra (Carex liparocarpos Gaudin, Seseli tortuosum L., etc.); 3.- nous per un ampli sector del nord-est

Aaron Pérez-Haase; Efrem Batriu; Arnau Mercadé López

2008-01-01

438

1 Introduzione alla Correlazione Elettronica 6 2 Teoria del Funzionale della Densit a 19  

E-print Network

Indice 1 Introduzione alla Correlazione Elettronica 6 2 Teoria del Funzionale della Densit#18;a 19 Teoria del Funzionale della Densit#18;a (DFT) [3] [4]. Tutte queste approssimazioni richiedono metodi DFT. Inoltre il QMC #18;e stato sovente usato per investigare le basi stesse della teoria del

Botti, Silvana

439

DEPARTAMENT DE FSICA, ENGINYERIA DE SISTEMES I TEORIA DEL SENYAL SECRETARIA  

E-print Network

Inici DEPARTAMENT DE FÍSICA, ENGINYERIA DE SISTEMES I TEORIA DEL SENYAL CONTACTE: HORARI DE SECRETARIA: Dept. de Física, Enginyeria de Sistemes i Teoria del Senyal Universitat d'Alacant Edifici'agost tancat NOTÍCIES I ESDEVENIMENTS Departament de Física, Enginyeria de Sistemes i Teoria del Senyal #12

Escolano, Francisco

440

BOLETN OFICIAL DEL ESTADO Nm. 279 Jueves 21 de noviembre de 2013 Sec. III. Pg. 92894  

E-print Network

ayudas para la formación de profesorado universitario de los subprogramas de Formación y de Movilidad Estatal de Movilidad. En cumplimiento de dichos objetivos, el Ministerio de Educación, Cultura y Deporte formación y movilidad del Programa Estatal de Promoción del Talento y su Empleabilidad, del Plan Estatal de

Rey Juan Carlos, Universidad

441

INICIO POLTICA ECONOMA MUNDO ESTADOS CAPITAL SOCIEDAD Y JUSTICIA CIENCIAS CULTURA ESPECTCULOS DEPORTES Noticias del da  

E-print Network

INICIO POLÍTICA ECONOMÍA MUNDO ESTADOS CAPITAL SOCIEDAD Y JUSTICIA CIENCIAS CULTURA ESPECTÁCULOS DEPORTES Noticias del día No hay noticias publicadas. Ciencias No hay noticias publicadas. BUSCAR Buscar en, del Instituto de Ciencias del Mar y Limnología de la UNAM La Jornada en línea Publicado: 24/01/2012 12

Islas, León

442

Conozca cuáles son las opciones de atención del cáncer en su comunidad  

Cancer.gov

Este artículo hace una presentación general de las funciones del programa de centros oncológicos designados por el NCI y del programa de investigación oncológica comunitaria del NCI en Estados Unidos, los cuales son una fuente importante de atención para pacientes con cáncer.

443

UNIVERSIDAD NACIONAL AUTNOMA DE MXICO Datos del plan de estudio  

E-print Network

Actividad Física y el Deporte Dirigido a: Comunidad Universitaria y Público General Síntesis o descripción. Significado del deporte vs. agresión Metodología: 1. Desarrollo de las capacidades biomotoras 2. Etapa de

Islas, León

444

UNIVERSIDAD NACIONAL AUTNOMA DE MXICO Datos del plan de estudio  

E-print Network

· Nutrición · Principios psicológicos del deportista · Recreación y deporte · Introducción al entrenamiento deporte · Plan de entrenamiento · Word Módulo III · Control médico deportivo · Preparación mental

Islas, León

445

UNIVERSIDAD NACIONAL AUTNOMA DE MXICO Datos del plan de estudio  

E-print Network

· Sistemas neuromusculares y endócrinos en el ejercicio · Motivación y emoción en el deporte · Trabajo con · Sistemas en el organismo · Actitud y deporte · Caracterización del entrenamiento deportivo · Aplicaciones

Islas, León

446

La Medicina del Lavoro e l'impact factor.  

PubMed

Lo spunto per la preparazione di questo editoriale è venuto dal rilascio, lo scorso 30 luglio, dei valori di impact factor 2013 da parte del Journal of Citation Records. L'impact factor è un parametro bibliometrico che qualifica il prestigio di una rivista.... PMID:25431979

Fustinoni, Silvia

2014-01-01

447

I CONGRESO INTERNACIONAL DEL AGUA .... por la vida  

E-print Network

Guayana, Estado Bolívar, Venezuela. Mesa # 7: Reducir los riesgos y hacer frente a la incertidumbre la naturaleza transversal y compleja del riesgo y el agua. 2. Riesgo y agua en Venezuela, un monitoreo poco consolidado para una exposición territorial a la amenaza alta. (3) Venezuela tiene

Paris-Sud XI, Université de

448

EL IMPACTO SOCIAL DEL SECTOR BANCARIO EN COLOMBIA, 1993 - 2002  

Microsoft Academic Search

Este documento estudia el impacto del sector bancario sobre variables sociales en Colombia, y busca identificar cómo la diferencia en el desarrollo de las instituciones bancarias a nivel municipal influye sobre la prosperidad económica y social de hogares de bajos recursos y de las empresas en esas localidades. El estudio busca identificar empíricamente cómo la bancarización o el acceso a

Juan Carlos Echeverry Garzón; Ángela María Fonseca Galvis

2006-01-01

449

Eficiencia, Equidad y Reestructuración Sectorial del Gasto Público Social  

Microsoft Academic Search

Es muy arriesgado suponer que la distribución sectorial del gasto público social corriente en los países en desarrollo es socialmente óptima. No obstante, sería también insensato pretender alterar completamente –y en el corto plazo- su distribución intersectorial con base en un análisis normativo. A partir de un statu quo subóptimo y siguiendo la idea básica de la teoría de la

Carlos Eduardo Vélez E

1997-01-01

450

LA NATURALESA DEL VALOR O EL VALOR DE LA NATURALESA  

E-print Network

-1790), David Ricardo (1772-1823) i Karl Marx (1818-1883), en fan la teoria del valor. Un assumpte de curiosa, a diferència de Karl Marx, accepta la dualitat entre valor d'ús i valor de canvi. Així, d'entrada, matisa el

Oro, Daniel

451

Visualization Queries Nicholas Del Rio and Paulo Pinheiro da Silva  

E-print Network

Visualization Queries Nicholas Del Rio and Paulo Pinheiro da Silva The University of Texas at El the notion of a query that describes a visualization request in terms of a universe of concepts, which on these concepts, users may be able to request for what properties they want to see in their visualizations (i

Ward, Karen

452

Introducción al estudio de la incidencia del gasto público  

Microsoft Academic Search

Se estudia la incidencia de los ingresos y gastos públicos en las diferentes regiones españolas. En lo que se refiere al gasto se utiliza dos enfoques de incidencia, según la fuente de datos empleada. Además se ofrece una segunda resultante de la imputación del gasto en presupuestos de nuestras Administraciones públicas entre las distintas regiones

Laura de Pablos Escobar

1998-01-01

453

Carbon sink forestali: quale governance del mercato dei crediti?  

E-print Network

11/10/2008 1 Carbon sink forestali: quale governance del mercato dei crediti? Davide Pettenella"" ((CarbonCarbon cheatingcheating)) "For its practical effect, telling people to plant trees is like telling carbon offsets ensure development benefits? Overseas Development Institute, Forestry Briefing 13 AA.. l

Pettenella, Davide

454

Control del dolor: Apoyo para las personas con cáncer  

Cancer.gov

Contiene información sobre las medicinas contra el dolor para pacientes con cáncer, los planes para controlarlo, cómo hablar con su equipo de atención médica sobre el dolor que usted siente y qué hacer para controlar los efectos físicos y emocionales del mismo.

455

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

456

Fundamentos del Anlisis Econmico Universidad de Alicante TEORIA ECO MICA  

E-print Network

Fundamentos del Análisis Económico Universidad de Alicante TEORIA ECO �MICA Curso 2010/11 Iñigo:30-14:30 Tutorías: Lunes: 14:30-16:30; Jueves: 9:30-12:30 Página de la asignatura: http://merlin.fae.ua.es/iturbe/Teoria

Escolano, Francisco

457

Dispense di Elementi di Teoria degli insiemi Giulio Del Corso  

E-print Network

GDC 1 Dispense di Elementi di Teoria degli insiemi (ETI) Giulio Del Corso Attenzione: Questi Teoria intuitiva ed introduttiva 7 Cardinalità 10 Teoria assiomatica ZFC 14 Aritmetica di Peano 16 Teoria delle classi 17 Buoni ordini 20 Ordinali 26 Cardinali #12;GDC 3 Teoria di Elementi di Teoria degli

Di Nasso, Mauro

458

VERBALE DEL COMITATO ETICO GIOVEDI' 19 FEBBRAIO 2009  

E-print Network

2009 3. Esame del progetto "Effects of an antioxidant-supplemented snack on oxidative stress: a pla "Effects of an antioxidant-supplemented snack on oxidative stress: a pla- cebo-controlled double titolo "Effects of an antioxidant-supplemented snack on oxidative stress: a placebo-controlled double

De Cindio, Fiorella

459

IUS Y LEX: LA NATURALEZA Y LÓGICA DEL PODER HUMANO  

Microsoft Academic Search

El presente trabajo fue expuesto por primera vez en el año de 1999, en una universidad local de la Paz, Baja California Sur. Se pretendía con éste, abrir brecha en la investigación pura, dentro del ámbito de las Ciencias Sociales, e ir despertando poco a poco el interés por las ciencias aplicadas en este campo. Como ya es moneda común

Héctor Murillo Aguilar

2008-01-01

460

La fisica del Novecento e Majorana Riccardo Barbieri  

E-print Network

La fisica del Novecento e Majorana Riccardo Barbieri Scuola Normale Superiore and INFN, Piazza dei'attivita' di Majorana in relazione con la fisica dell'intero Novecento, cercando di proiettare questa relazione nel futuro: il ruolo delle simmetrie nella fisica delle interazioni cosiddette fondamentali. #12

Abbondandolo, Alberto

461

La coordinación entre niveles asistenciales: del discurso al proyecto transformador  

Microsoft Academic Search

La falta de coordinación entre los diferentes niveles asistenciales, y particularmente entre atención primaria y hospitales ha suscitado miles de artículos, debates técnicos y polémicas encendidas, pero escasos avances prácticos. La persistencia del problema se debe indudablemente a su complejidad, porque la existencia de talento y experiencia generosamente distribuido en el sistema sanitario en teoría deberían haber provocado el desarrollo

Raimon Belenes

2009-01-01

462

ESTUDIO ESPACIO-TEMPORAL DEL CONSUMO DE HIGOS  

Microsoft Academic Search

El higo (Ficus carica, L), es un sicona dc una influorescencia, repleto de granos o flores fecundadas, recubierto de una piel fina de color y aspecto variables. Se origina de un arbusto de la familia de las Moráceas, especie Ficus carica, cuyo cultivo está muy extendido en el Mediterráneo y en zonas cálidas. El consumo del higo es muy apreciado

M. C. Gallego; R. Angulo; S. Serrano; M. Jodral

1996-01-01

463

The Delaware Model: A Systems Approach (Del Mod System).  

ERIC Educational Resources Information Center

This monograph presents a description, along with the purposes, of the Del Mod System. It is described as a system concerned with inducing changes in the existing systems in the area of science education. The investment of time and funds (a National Science Foundation-funded project) is devoted to an alteration of the behavior patterns of…

Purnell, Charlotte H.

464

Las zonas mineras españolas a finales del XIX  

Microsoft Academic Search

PRESENTACIÓN Jugh James Rose, capellán de las compañías mineras inglesas, francesas y alemanas de Linares, es el autor de la obra Untrodden Spain and her black country being sketches of the life and character of the Spaniard of the interior publicada en dos volúmenes en Londres en 1875. De él sabemos que ejerció como capellán del ejército en Dover y

María Antonia López Burgos

2003-01-01

465

Del Mod: A State-Wide System for School Improvement.  

ERIC Educational Resources Information Center

This is a retrospective account of the Del Mod System, a statewide project to improve science and mathematics education in the elementary and secondary schools of Delaware. The project functioned from 1970-76 under the auspices of a committee including the presidents of institutions of higher education, the state superintendent of public…

Neale, Daniel C.

466

How Can Psychology Help Artificial Intelligence Alvaro del Val  

E-print Network

This paper discusses the relationship between Artificial Intelligence (AI) and Psychology. As an AIHow Can Psychology Help Artificial Intelligence Alvaro del Val Departamento de Ingenier'ia Inform Artificial intelligence is interdisciplinary in its very nature, and has from its birth benefited by input

del Val, Alvaro

467

Formalizaci on del razonamiento ecuacional en una l ogica computacional  

E-print Network

Formalizaci#19;on del razonamiento ecuacional en una l#19;ogica computacional J.L. Ruiz, J formalizaci#19;on en una l#19;ogica computacional (la l#19;ogica de ACL2), de diversas propiedades de la l#19 propiedades de sistemas de computaci#19;on, la denominamos l#19;ogica computacional. La principal ventaja que

Reina, José Luis Ruiz

468

Esercitazione del 28 febbraio 2003 Progetto del sistema di controllo di vibrazione per la sospensione di un'automobile  

E-print Network

sospensione di un'automobile (sospensione attiva) Il sistema raffigurato rappresenta lo schema semplificato pneumatico-ammortizzatore-telaio di un'automobile. Il sistema è caratterizzato dalla massa equivalente M dell'automobile esercitare sulla ruota e sul telaio dell'automobile e come azione disturbante d il profilo dell'asperità del

Monaco, Salvatore

469

Esercitazione del 14 febbraio 2003 Progetto del sistema di controllo di vibrazione per la sospensione di un'automobile  

E-print Network

sospensione di un'automobile (sospensione attiva) Il sistema raffigurato rappresenta lo schema semplificato pneumatico-ammortizzatore-telaio di un'automobile. Il sistema è caratterizzato dalla massa equivalente M dell'automobile esercitare sulla ruota e sul telaio dell'automobile e come azione disturbante d il profilo dell'asperità del

Monaco, Salvatore

470

Esercitazione del 21 marzo 2003 Progetto del sistema di controllo di vibrazione per la sospensione di un'automobile  

E-print Network

di un'automobile (sospensione attiva) Il sistema raffigurato rappresenta lo schema semplificato pneumatico-ammortizzatore-telaio di un'automobile. Il sistema è caratterizzato dalla massa equivalente M dell'automobile esercitare sulla ruota e sul telaio dell'automobile e come azione disturbante d il profilo dell'asperità del

Monaco, Salvatore

471

Esercitazione del 7 marzo 2003 Progetto del sistema di controllo di vibrazione per la sospensione di un'automobile  

E-print Network

di un'automobile (sospensione attiva) Il sistema raffigurato rappresenta lo schema semplificato pneumatico-ammortizzatore-telaio di un'automobile. Il sistema è caratterizzato dalla massa equivalente M dell'automobile esercitare sulla ruota e sul telaio dell'automobile e come azione disturbante d il profilo dell'asperità del

Monaco, Salvatore

472

Estrategia innovadora enfocada en parejas del mismo sexo para disminuir la infección del VIH en hombres Latinos  

PubMed Central

Resumen El VIH es un problema de salud importante dentro de la comunidad latina de los Estados Unidos. Gracias a los esfuerzos de prevención, los niveles de contagio entre los latinos se han mantenido estables por más de una década. Sin embargo, esta población sigue siendo afectada a niveles muy altos, en particular entre hombres que tienen sexo con hombres (HSH), de origen latino y que hablan principalmente el idioma español. Existen varios factores que contribuyen a la transmisión del VIH entre esta población, como son: el uso de drogas; la violencia dentro de la pareja; la presencia de infecciones de transmisión sexual; relaciones sexuales sin protección, dentro y fuera de la pareja; el evadir la búsqueda de recursos (prueba y tratamiento adecuado) por temor a ser discriminado o por su estatus migratorio; la escasez de recursos económicos o estado de pobreza y los patrones relacionados a la migración. En particular, Investigaciones Epidemiológicas de Comportamientos han determinado: cómo algunas dinámicas en parejas están directamente asociadas a los comportamientos sexuales de riesgos. En consecuencia, es necesaria mayor investigación para identificar esas dinámicas, y a su vez, realizar intervenciones dirigidas a la reducción de conductas de riesgo enfocadas en parejas de hombres del mismo sexo. En este escrito, se describe la importancia del uso de las relaciones de pareja como estrategia en la reducción de la trasmisión del VIH/SIDA en HSH de origen latino y que hablan principalmente el idioma español en los Estados Unidos.

Martinez, Omar; Wu, Elwin; Sandfort, Theo; Shultz, Andrew Z.; Capote, Jonathan; Chávez, Silvia; Moya, Eva; Dodge, Brian; Morales, Gabriel; Porras, Antonio; Ovejero, Hugo

2014-01-01

473

Evidence for single origins of 35delG and delE120 mutations in the GJB2 gene in Anatolia.  

PubMed

Eighteen different sequence changes, including three novel alterations, were detected in GJB2, encoding connexin 26, in 371 Turkish probands with non-syndromic sensorineural hearing loss. Two frequently detected mutations, 35delG and delE120, were shown to have single origins based on the conserved genotypes of two closely linked microsatellite and five single nucleotide polymorphism markers. Carrier frequencies of 35delG and delE120 in Egypt and Turkic populations of the Near East provide insights about the origin of these two mutations. PMID:15617546

Tekin, M; Bo?oclu, G; Arican, S T; Orman, M N; Tastan, H; Elsobky, E; Elsayed, S; Akar, N

2005-01-01

474

Identificación de los miembros del cúmulo NGC 2516  

NASA Astrophysics Data System (ADS)

El cúmulo abierto NGC 2516 (? = 7h 58m y ? = -60o 45') tiene una edad de, aproximadamente, 150 Myr. El análisis de este sistema es particularmente importante en el Hemisferio Sur debido a su abundancia de estrellas peculiares y muy estudiado aplicando técnicas fotométricas, pero muy poco analizado desde el punto de vista astrométrico. A partir de una placa obtenida en el Observatorio Astronómico de La Plata y observaciones más actuales, nos hemos abocado al estudio de los movimientos propios de este cúmulo con el fin de determinar la pertenencia al mismo de las estrellas del campo de dicho cúmulo. Luego de llevar a cabo la determinación de los movimientos propios de todas las estrellas a partir de las posiciones obtenidas de la placa existente en el Observatorio de La Plata de 1914 y leídas con la MAMA en París, las observaciones realizadas con el círculo meridiano de San Fernando que se encuentra en el Observatorio Félix Aguilar de San Juan y las posiciones existentes en los catálogos AC 2000, Tycho, USNO y UCAC, programamos el método de Vasilevsky y Sanders para determinar la pertenencia de las estrellas de la región al cúmulo en cuestión. En un paso posterior, se realizó una modificación al método anterior para la determinación de los miembros. En esta modificación se consideró la densidad de las estrellas del cúmulo y la densidad de estrellas de campo. Esto permitió evaluar la pertenencia, no sólo a partir del movimiento propio de las estrellas, sino también a partir de la posición de las mismas con respecto al centro del cúmulo. También se consideró la dependencia de los parámetros con la magnitud. Los resultados así obtenidos fueron comparados con otras investigaciones de movimientos propios de la región del cúmulo. El movimiento propio absoluto del cúmulo fue comparado con el obtenido a partir de los catálogos estelares. Se encontró que los resultados coincidían para estrellas brillantes (magnitud más brillante que 12.0 aproximadamente) y que no coincidían para estrellas más débiles. La tarea que llevamos a cabo en estos momentos está referida a encontrar la causa de tales discrepancias con el fin de obtener los mejores resultados.

de Elía, G. C.; Orellana, R. B.

475

Analisis del contenido curricular de los Documentos Normativos del Programa de Ciencias en el area de biologia para la escuela superior del sistema de educacion publica de Puerto Rico: 1993-2012  

NASA Astrophysics Data System (ADS)

Esta investigacion de naturaleza cualitativa se ocupo de realizar un analisis de contenido documental de los Documentos Normativos del Programa de Ciencias en el area de biologia de la escuela superior del sistema de educacion publica de Puerto Rico del periodo 1993-2012. Los documentos analizados fueron: Guia Curricular, 1995; Marco Curricular, 2003; Estandares de Excelencia, 1996, 2000 y Estandares de Contenido y Expectativas de Grado, 2007. Se indago si hubo cambios en significados en los Componentes Estructurales: Naturaleza de la ciencia, Paradigmas para la ensenanza de la ciencia, Funcion del curriculo formal, Mision de la ensenanza de la ciencia; Contenidos, destrezas y competencias, Estrategias de ensenanza y Evaluacion/Assessment del aprendizaje. El analisis sugiere que no hubo cambios sustanciales en los significados de los Componentes Estructurales. Los documentos estudiados muestran mayormente caracteristicas similares, aunque los documentos mas recientes eran mas descriptivos, explicativos y especificos.

Davila Montanez, Melissa

476

Propuesta de un mecanismo de estabilización de precios de los combustibles a través del uso de instrumentos financieros derivados  

Microsoft Academic Search

El presente estudio propone la discusión de los fundamentos de la utilización de un mecanismo basado en el uso de instrumentos financieros de cobertura para la mitigación del impacto de la volatilidad del precio del petróleo en el costo de sus productos derivados. A fin de contribuir a la consideración de alternativas se plantea aquí también la posible complementación del

Juan Antonio Zapata; Carlos Gabriel Rivas; Alejandro Melandri

2012-01-01

477

AREA ANEP REFERENCIA NOMBRE CENTRO PROVINCIA FISICA Y CIENCIAS DEL ESPACIO 11-675-01-01 GIANLUCA CALGAGNI IEM MADRID  

E-print Network

AREA ANEP REFERENCIA NOMBRE CENTRO PROVINCIA FISICA Y CIENCIAS DEL ESPACIO 11-675-01-01 GIANLUCA CALGAGNI IEM MADRID FISICA Y CIENCIAS DEL ESPACIO 11-675-01-02 MERCEDES LOPEZ MORALES ICE BARCELONA FISICA Y CIENCIAS DEL ESPACIO 11-675-01-03 MICHELE DELLA MORTE IFIC VALENCIA FISICA Y CIENCIAS DEL ESPACIO

Fitze, Patrick

478

La "conversione" delle cellule della cute che producono insulina: nuova arma contro diabete e tumore del pancreas  

E-print Network

tumore del pancreas Uno studio dell'Università degli Studi di Milano su PNAS scopre un metodo, sicuro alterarne il DNA. Straordinarie le potenzialità nella terapia del diabete e del tumore al pancreas. La i vari tipi di diabete e per il tumore del pancreas. La ricerca, finanziata da AIRC, MIUR e Regione

De Cindio, Fiorella

479

El camino México-Toluca. Proyecto del ingeniero militar Manuel Agustín Mascaró. Nueva España, 1791–1795  

Microsoft Academic Search

En este estudio exponemos diversos asuntos y circunstancias que acontecieron en torno al proyecto del camino México-Toluca realizado por el ingeniero militar Manuel Agustín Mascaró. Comenzamos con un esbozo biográfico del autor y una descripción general del proyecto para continuar con la explicación del contexto histórico en que se realizó tanto el manuscrito como la obra, desde la importancia socio-económica

María del Carmen León García

2007-01-01

480

Prognostic Impact of del(17p) and del(22q) as Assessed by Interphase FISH in Sporadic Colorectal Carcinomas  

PubMed Central

Background Most sporadic colorectal cancer (sCRC) deaths are caused by metastatic dissemination of the primary tumor. New advances in genetic profiling of sCRC suggest that the primary tumor may contain a cell population with metastatic potential. Here we compare the cytogenetic profile of primary tumors from liver metastatic versus non-metastatic sCRC. Methodology/Principal Findings We prospectively analyzed the frequency of numerical/structural abnormalities of chromosomes 1, 7, 8, 13, 14, 17, 18, 20, and 22 by iFISH in 58 sCRC patients: thirty-one non-metastatic (54%) vs. 27 metastatic (46%) disease. From a total of 18 probes, significant differences emerged only for the 17p11.2 and 22q11.2 chromosomal regions. Patients with liver metastatic sCRC showed an increased frequency of del(17p11.2) (10% vs. 67%;p<.001) and del(22q11.2) (0% vs. 22%;p?=?.02) versusnon-metastatic cases. Multivariate analysis of prognostic factors for overall survival (OS) showed that the only clinical and cytogenetic parameters that had an independent adverse impact on patient outcome were the presence of del(17p) with a 17p11.2 breakpoint and del(22q11.2). Based on these two cytogenetic variables, patients were classified into three groups: low- (no adverse features), intermediate- (one adverse feature) and high-risk (two adverse features)- with significantly different OS rates at 5-years (p<.001): 92%, 53% and 0%, respectively. Conclusions/Significance Our results unravel the potential implication of del(17p11.2) in sCRC patients with liver metastasis as this cytogenetic alteration appears to be intrinsically related to an increased metastatic potential and a poor outcome, providing additional prognostic information to that associated with other cytogenetic alterations such as del(22q11.2). Additional prospective studies in larger series of patients would be required to confirm the clinical utility of the new prognostic markers identified. PMID:22912721

González-González, María; Muñoz-Bellvis, Luís; Mackintosh, Carlos; Fontanillo, Celia; Gutiérrez, M. Laura; Abad, M. Mar; Bengoechea, Oscar; Teodosio, Cristina; Fonseca, Emilio; Fuentes, Manuel; De Las Rivas, Javier

2012-01-01

481

Le Thorium Molten Salt Reactor : Au del du MSBR  

E-print Network

Le Thorium Molten Salt Reactor : Au delà du MSBR L. Mathieu, D. Heuer, A. Billebaud, R. Brissot, C réflexion est menée afin de trou- ver des solutions et ainsi d'aboutir au concept du Thorium Mol- ten Salt optimale du minerai d'uranium ou de thorium, une conception résistante à la prolifération, une meilleur

Paris-Sud XI, Université de

482

ESTUDIO HIDROQUIMICO DEL ACUFERO DE LA VEGA DE GRANADA  

E-print Network

Aguas de superficie Aguas residuales urbanas Aguas residuales industriales Aguas de infiltración. El el título, sobre la hidroquímica (calidad y contaminación) de las aguas de la Vega de Granada. En) Confederación Hidrográfica y Comisaría de Aguas del Guadalquivir (Granada) Colegio farmacéutico y Consejería de

Castillo, Antonio

483

El presidente Obama anuncia nombramiento del doctor Harold Varmus  

Cancer.gov

En un correo electrónico enviado al personal del NCI, el doctor Francis Collins, director de los Institutos Nacionales de la Salud, dijo que Varmus “trae consigo un experiencia sin igual a todo nivel, no solo en la investigación científica más avanzada, sino también como líder en la creación de estrategias para mejorar el cuidado de los pacientes, la educación científica, la capacitación y el diseño de novedosas alianzas entre el sector público y el privado”.

484

Weak approximation on del Pezzo surfaces of degree 1  

E-print Network

We study the arithmetic of del Pezzo surfaces of degree 1 of the form w^2 = z^3 + Ax^6 + By^6 in the weighted projective space P_k(1,1,2,3), where k is a perfect field of characteristic not 2 or 3 and A,B \\in k^*. We exhibit an infinite family of (minimal) counterexamples to weak approximation amongst these surfaces, via a Brauer-Manin obstruction.

Várilly-Alvarado, Anthony

2008-01-01

485

del(7q) in chronic B-cell lymphoid malignancies  

Microsoft Academic Search

Twelve patients with diagnosis of B-cell non-Hodgkin's lymphoma\\/leukemia and del(7q) were studied for their clinical, cytogenetic, and molecular characteristics. Eleven patients were classified as small cell lymphoma whereas one had a diffuse large cell lymphoma. Lymphoplasmacytic features were observed in six out of eleven small cell lymphomas. Morphologically and immunologically these small cell lymphomas could be classified as chronic lymphocytic

Jesús María Hernandez; Cristina Mecucci; Lucienne Michaux; Arnold Criel; Michel Stul; Peter Meeus; Iwona Wlodarska; Angeline Van Orshoven; Jean-Jacques Cassiman; Christiane De Wolf-Peeters; Herman Van Den Berghe

1997-01-01

486

Las ciudades de Andalucía ante la sociedad del conocimiento  

Microsoft Academic Search

La relación entre competitividad económica y posicionamiento de los territorios en la sociedad del conocimiento cobra cada vez mayor protagonismo. Despiertan así especial interés aquellos ámbitos que realizan un esfuerzo por incrementar la producción, difusión y aplicación de conocimiento para mejorar el funcionamiento de sus empresas y la calidad de vida de sus habitantes.\\u000aPor su parte, las ciudades se

Ricardo Méndez Gutiérrez del Valle; Luis Abad Aragón; Inmaculada Caravaca Barroso; Gema González Romero

2010-01-01

487

Maximally inhomogeneous G\\"{o}del-Farnsworth-Kerr generalizations  

E-print Network

It is pointed out that physically meaningful aligned Petrov type D perfect fluid space-times with constant zero-order Riemann invariants are either the homogeneous solutions found by G\\"{o}del (isotropic case) and Farnsworth and Kerr (anisotropic case), or new inhomogeneous generalizations of these with non-constant rotation. The construction of the line element and the local geometric properties for the latter are presented.

Wylleman, Lode

2012-01-01

488

La computacin y sus versiones : El Debate del Software  

E-print Network

La computación y sus versiones : El Debate del Software Software Libre vs. Software Privativo Pablo controladas por el código (el software). Pero ... ¿Quién controla el código? ¿De quién recibe órdenes tu computadora? ¿Tenemos derecho a saber exactamente qué hace nuestra computadora? #12;¿Qué es el Software Libre

De Nápoli, Pablo Luis

489

Teoria simmetrica dell’elettrone e del positrone  

Microsoft Academic Search

Sunto  \\u000a Si dimostra la possibilità di pervenire a una piena simmetrizzazione formale della teoria quantistica dell’elettrone e del\\u000a positrone facendo uso di un nuovo processo di quantizzazione. Il significato delle equazioni di\\u000a Dirac\\u000a ne risulta alquanto modificato e non vi è più luogo a parlare di stati di energia negativa; nè a presumere per ogni altro\\u000a tipo di particelle, partieolarmente

Ettore Majorana

1937-01-01

490

María Asunción Requena: Éxito e historia del teatro  

E-print Network

Universidad de Concepción. Ganó el Premio al XXX aniversario del DETUCH (Departamento de Teatro de la Universidad de Chile) con Chiloé, cielos cubiertos en 1971. Este texto fue puesto en escena en 1972 en Santiago. En el mismo año se estrenó en Santiago... Televisión dieron mucha importancia a la posibilidad de atraer teleespectadores con el renombre y prestigio de los actores y actrices: Roberto Parada, Rafael Benavente, Teodoro Lowey, Tennyson Ferrada, Ana González, Sonia Viveros y otros. Veintiocho...

Villegas, Juan

1995-04-01

491

Récord de longevidad del Correlimos Zarapitín (Calidris ferruginea)  

Microsoft Academic Search

En aquesta nota es descriu el control d'un territ bec-llarg disset anys després del seu anellament. L'ocell es va marcar com a jove el 5 de setembre de 1975 a Friesland (Holanda) i es va recapturar el 3 d'agost de 1992 al delta de l'Ebre, 6173 dies després de l'anellament. Fins ara la màxima longevitat demostrada per a aquesta espècie

Jordi Figuerola

1995-01-01

492

Wetlands of the Magellanic Steppe (Tierra Del Fuego, Argentina)  

Microsoft Academic Search

Our main objective was to classify vegetation and soils of wetlands in northern Tierra del Fuego (Argentina) along a latitudinal\\u000a precipitation gradient within the Magellanic Steppe Zone. We presented the first detailed ecological characterization of these\\u000a wetlands by relating floristic composition to local site conditions, bedrock and climate. The survey consisted of 125 phytosociological\\u000a censuses and 52 soil profile descriptions.

Marta B. Collantes; Juan A. Anchorena; Susana Stoffella; Celina Escartín; Ruth Rauber

2009-01-01

493

PRCTICAS OCULTAS DE LOS "ANUSI11" DEL NUEVO MUNDO  

E-print Network

PRÁCTICAS OCULTAS DE LOS "ANUSI11" DEL NUEVO MUNDO ScHL:lA\\llTH C. H ALEVY* N ..\\CHl!'.1 DERSHO\\\\'ITZ* \\1CCHOS de los judíos de España y Portugal que fueron obligados a con- \\'ertirse al cristianismo (llamados anusim en hebreo) y sus descendientes, emigraron a América.1 Sabemos por los archivos de la Santa

Dershowitz, Nachum

494

Solar adaptive optics at the Observatorio del Teide, Tenerife  

NASA Astrophysics Data System (ADS)

Observing the Sun with high angular resolution is difficult because the turbulence in the atmosphere is strongest during day time. In this paper we describe the principles of solar adaptive optics exemplified by the two German solar telescopes VTT and GREGOR at the Observatorio del Teide. With theses systems we obtain near diffraction limited images of the Sun. Ways to overcome the limits of conventional AO by applying multiconjugate adaptive optics (MCAO) are shown.

Soltau, Dirk; Berkefeld, Thomas; Schmidt, Dirk; von der Lühe, Oskar

2013-10-01

495

EMPLAZAMIENTO DE NIDOS DE ARDILLA ROJA Sciurus vulgaris EN MELOJARES Y SETOS ARBOLADOS DEL VALLE DEL RÍO TORÍO (LEÓN, NO DE ESPAÑA)  

Microsoft Academic Search

RESUMEN Se describe el emplazamiento de 49 nidos de ardilla roja Sciurus vulgaris en setos arbolados (n=28), plantaciones de chopos (n=14) y bordes de melojares (n=7) del valle del río Torío (León). Todos los nidos encontrados en melojares y plantaciones de chopos estaban instalados en melojos Quercus pyrenaica y chopos híbridos Populus x canadensis, respectivamente, debido al carácter prácticamente monoespecífico

A. HERNÁNDEZ

496

Nuevo sitio web en español del Instituto Nacional del Cáncer, (NCI, por sus siglas en inglés) Cancer.gov en español - Silvia Inéz Salazar - transcript  

Cancer.gov

Transmisiones de radio para promover Cancer.gov en espa%XF1ol | Nuevo sitio web en espa%XF1ol del Instituto Nacional del C%XE1ncer, (NCI, por sus siglas en ingl%XE9s) Cancer.gov en espa%XF1ol | Transcripci%XF3n Transmisiones de radio para promover

497

PROPUESTA DE UN SISTEMA DE GESTIÓN DE LOS COSTOS DE CALIDAD EN LA AGROINDUSTRIA ARROCERA DEL CAI FERNANDO ECHENIQUE DEL MUNICIPIO YARA  

Microsoft Academic Search

El trabajo fue realizado en la agroindustria arrocera del CAI Fernando Echenique ubicado en la Provincia Granma, en el cual se concentra el 70 por ciento de la producción de arroz de la región oriental del país. El estudio abarcó las Granjas arroceras Bartolomé Masó Márquez y Pedro Borrás Astorga, y la Unidad industrial de Beneficio Emilio Lastre, a partir

Yudelquis Ramírez Pérez; Sandy Rodríguez Sosa; Odalis Reyes Alarcón

2012-01-01

498

El barrio del Raval de Barcelona (1999-2008). Transformaciones urbanas y nuevos enfoques metodológicos para el estudio del centro histórico  

Microsoft Academic Search

Los centros históricos de las ciudades europeas experimentan actualmente importantes transformaciones urbanas que han contribuido a que dichas áreas se convirtieran en objeto de estudio por parte de distintas disciplinas. Éste es el caso del centro histórico de Barcelona, particularmente el barrio del Raval, cuyos cambios en los últimos diez años (1999-2008) se han abordado desde áreas de conocimiento como

Ma. Alba Sargatal Bataller

2009-01-01

499

The 2012 Reactivation of Nevado del Ruiz Volcano, Colombia  

NASA Astrophysics Data System (ADS)

Nevado Del Ruiz volcano is most known for its tragic November 13, 1985 explosive event, when a small eruption produced an enormous lahar that buried and destroyed the town of Armero in Tolima, causing an estimated 25,000 deaths. Similar but less deadly incidents occurred in 1595 and 1845, again where a small explosive eruption was followed by a large lahar. Other minor explosive events occurred in 1805, 1828-9, and 1989. The Armero tragedy was a major factor in the establishment of a volcano monitoring program in Colombia. The network monitoring Nevado del Ruiz volcano has dramatically improved since the 1985 eruption and now includes geodetic, geophysical, geochemical and visual monitoring. The activity of Nevado Del Ruiz between 1985 and 1991 saw significant increases in seismicity and significant gas emissions with the main eruptive events of November 13, 1985 and September 1st, 1989. The volcano became seismically active again in 1995 and 2002, whit an increase in seismicity, without any gas emission or eruption. In October 2010 the volcano entered in a new phase of unrest with increased seismicity (HB events), deformation and gas emissions, likely associated with a new magma intrusion. In February, 2012 the volcano had a new and significant increase in seismicity (VT-LP), followed in May and June 2012 by small phreatic and phreato-magmatic eruption. This eruptive activity is still ongoing. Deformation measurements at Nevado Del Ruiz volcano have been carried out since just after the tragic eruption of the 13th of November 1985. In 2007 seven new electronic tilt meters were set up to monitor the deformation. Significant uplift was measured from August 2007 to October 2010, for a total cumulative value of more than 500 microradians. From the end of 2011 to July 2012, moderate changes of uplift were detected for a total of 70 microradians. The analysis of these deformation data shows a pattern of surface displacement associated with an intrusion of new magma coming from a reservoir located approximately at a depth of approximately 8 km and accumulating in shallow reservoir less than 2 km beneath the main crater. We fit the data with both a spherical and a vertical spheroid source. The spherical source indicates the existence of an intrusion at a depth of 1823±1056 m with a volume change of (7±17)×106 m3 . The vertical spheroidal source suggests a source 1855 m deep with a volume change of 6×106 m3 . These results imply that while we have strong bounds on the depth of the intrusion, the actual volume of the source is less certain. Gas emission from Nevado del Ruiz volcano in April 7, 2012.

Ordoñez, M.; Lopez, C.; Cortes, G. P.; Londoño, J.; Battaglia, M.

2012-12-01

500

Estudios en la Zona no Saturada del Suelo. Vol X ALGORITMO MECANSTICO SIMPLIFICADO PARA LA CUANTIFICACIN DEL EFECTO DE UN  

E-print Network

encharcamiento del suelo y balance de agua durante un hietograma de lluvia natural. El modelo se contrasta se estudia la extensión de la ecuación de Green-Ampt para la infiltración de agua en presencia de un nivel freático somero estable bajo condiciones de lluvia natural, y su efecto sobre la redistribución de

Boyer, Edmond