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1

Segmented stator assembly  

DOEpatents

An electric machine and stator assembly are provided that include a continuous stator portion having stator teeth, and a tooth tip portion including tooth tips corresponding to the stator teeth of the continuous stator portion, respectively. The tooth tip portion is mounted onto the continuous stator portion.

Lokhandwalla, Murtuza; Alexander, James Pellegrino; El-Refaie, Ayman Mohamed Fawzi; Shah, Manoj Ramprasad; Quirion, Owen Scott

2013-04-02

2

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

3

Stator and method of assembly  

DOEpatents

The present application provides a stator. The stator may include a number of poles and a stator tip and cooling assembly. The stator tip and cooling assembly may include a number of stator tips with a number of cooling tubes adjacent thereto such that the stator tips align with the poles and the cooling tubes cool the poles.

Alexander, James Pellegrino; El-Refaie, Ayman Mohamed Fawzi; Shen, Xiaochun

2013-06-18

4

DIAGNOSTICO Y PROPUESTA DE MEJORAMIENTO DE PROCESOS DE ENTRENAMIENTO. TRANSFERENCIA Y GESTION DEL CONOCIMIENTO: CASO TELEFÒNICA MÒVILES COLOMBIA S.A  

Microsoft Academic Search

RESUMEN: Esta investigación busca identificar las mejores prácticas de entrenamiento organizacional que garantizan la transferencia del conocimiento impartido a los empleados a sus lugares de trabajo, determinando los factores que influyen en su generación y conservación, basado en la aplicación de metodologías tanto cua- litativas como cuantitativas que diagnostican los procesos actuales de una empresa de telecomunicaciones, permitiendo un control

M. L. Granados

5

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.

Fanning, Alan W. (San Jose, CA); Olich, Eugene E. (Aptos, CA); Dahl, Leslie R. (Livermore, CA)

1995-01-01

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.

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

7

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

8

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

9

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

10

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

11

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

12

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

13

Turbogenerator with high voltage stator windings  

Microsoft Academic Search

In this paper the design of a turbogenerator with high voltage stator winding is presented. In distinction from conventional techniques the stator winding is not built with isolated bars. For this concept, common high voltage cables are used. Therefore it is possible to raise the stator voltage from 110 kV to 400 kV. The advantage of this concept is that

D. Flockermann; S. Kulig

2001-01-01

14

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.

Fanning, Alan W. (San Jose, CA)

1995-01-01

15

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

16

Analytical and experimental investigation of stator endwall contouring in a small axial-flow turbine. 1: Stator performance  

NASA Technical Reports Server (NTRS)

Three stator configurations were studied to determine the effect of stator outer endwall contouring on stator performance. One configuration was a cylindrical stator design. One contoured stator configuration had an S-shaped outer endwall, the other had a conical-convergent outer endwall. The experimental investigation consisted of annular surveys of stator exit total pressure and flow angle for each stator configuration over a range of stator pressure ratio. Radial variations in stator loss and aftermixed flow conditions were obtained when these data were compared with the analytical results to assess the validity of the analysis, good agreement was found.

Haas, J. E.

1982-01-01

17

Nonlinearly stacked low noise turbofan stator  

NASA Technical Reports Server (NTRS)

A nonlinearly stacked low noise turbofan stator vane having a characteristic curve that is characterized by a nonlinear sweep and a nonlinear lean is provided. The stator is in an axial fan or compressor turbomachinery stage that is comprised of a collection of vanes whose highly three-dimensional shape is selected to reduce rotor-stator and rotor-strut interaction noise while maintaining the aerodynamic and mechanical performance of the vane. The nonlinearly stacked low noise turbofan stator vane reduces noise associated with the fan stage of turbomachinery to improve environmental compatibility.

Schuster, William B. (Inventor); Kontos, Karen B. (Inventor); Weir, Donald S. (Inventor); Nolcheff, Nick A. (Inventor); Gunaraj, John A. (Inventor)

2009-01-01

18

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

19

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

20

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

21

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

22

Axial flux machine, stator and fabrication method  

DOEpatents

An axial flux machine comprises: a soft magnetic composite stator extension positioned in parallel with a rotor disk and having slots; soft magnetic composite pole pieces attached to the stator extension and facing a permanent magnet on the rotor disk, each comprising a protrusion situated within a respective one of the slots, each protrusion shaped so as to facilitate orientation of the respective pole piece with respect to the stator extension; electrical coils, each wrapped around a respective one of the pole pieces. In another embodiment the soft magnetic composite pole pieces each comprise a base portion around with the electrical coils are wound and a trapezoidal shield portion a plurality of heights with a first height in a first region being longer than a second height in a second region, the second region being closer to a pole-to-pole gap than the first region.

Carl, Ralph James

2004-03-16

23

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

24

Process for revamping the stator blades of a gas turbine  

Microsoft Academic Search

A process is described for revamping the stator blades of a gas turbine, comprising the steps of: removing the stator blades of a gas turbine by severing the upper portions of the stator blades in a base ring section of an axial flow compressor case of the gas turbine with an arc air torch, thereby leaving lower stud portions of

B. H. Reaves; W. E. Nelson

1989-01-01

25

Mud motor stator temperature analysis technique  

SciTech Connect

The power section of a mud driven progressing cavity drill motors consists of a steel rotor shaped with an external helix rotating within a stationary tube with a molded helical elastomeric lining (stator). Operating temperature of the elastomer lining is an important parameter that affects the stator life. Motor operating conditions such as down hole temperature, torque, differential pressure, and speed determine the elastomer temperature. This paper presents an analysis technique to predict stator elastomer temperature as a function of the motor`s operating parameters. A non-linear finite element analysis technique is used to predict the stator temperature. Physical and mechanical properties of the elastomer are measured, using laboratory equipment such as Monsanto`s RPA2000 dynamic analyzer and BFGoodrich model (II) flexometer. Boundary conditions of the finite element model are defined based on the down hole temperature, differential pressure, and the motor`s speed. Results of the finite element analysis are compared with laboratory test data to verify the accuracy of the analysis.

Delpassand, M.S. [Moyno Oilfield Products, Fairfield, CA (United States)

1995-12-31

26

Diagnostico de Prenez en Ganado Vacuno.  

E-print Network

poco despues de nacer debido a accidentes y enfei-inedades. HabrA una pequefia diferencia entre este porcentaje de becerros logrados y aquel calculado con el numero de l~ecerros nacidos. La tabla 1 indica el costo por libra de res pro- clucida... li~teo tanll,ii.n puetle ser p:ulp:ttlo en el ov:urio por una person;i con experienci;~. Un foliculo gr;uitle en el ovario indica que el animal se aproxim;~ it1 pcriodo de celo. Un cuerpo luteo en el ovxio indica que la vaca esti cerca del punto...

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

1975-01-01

27

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

28

Heat transfer in rotor/stator cavity  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

29

A Survey of Methods for Detection of Stator-Related Faults in Induction Machines  

Microsoft Academic Search

As evidenced by industrial surveys, stator-related failures account for a large percentage of faults in induction machines. The objective of this paper is to provide a survey of existing techniques for detection of stator-related faults, which include stator winding turn faults, stator core faults, temperature monitoring and thermal protection, and stator winding insulation testing. The root causes of fault inception,

Rangarajan M. Tallam; Sang Bin Lee; Greg C. Stone; Gerald B. Kliman; Jiyoon Yoo; Thomas G. Habetler; Ronald G. Harley

2007-01-01

30

Evaluation of ceramics for stator application: Gas turbine engine report  

NASA Technical Reports Server (NTRS)

Current ceramic materials, component fabrication processes, and reliability prediction capability for ceramic stators in an automotive gas turbine engine environment are assessed. Simulated engine duty cycle testing of stators conducted at temperatures up to 1093 C is discussed. Materials evaluated are SiC and Si3N4 fabricated from two near-net-shape processes: slip casting and injection molding. Stators for durability cycle evaluation and test specimens for material property characterization, and reliability prediction model prepared to predict stator performance in the simulated engine environment are considered. The status and description of the work performed for the reliability prediction modeling, stator fabrication, material property characterization, and ceramic stator evaluation efforts are reported.

Trela, W.; Havstad, P. H.

1978-01-01

31

Noise of fan designed to reduce stator lift fluctuations  

NASA Technical Reports Server (NTRS)

An existing fan stage was redesigned to reduce stator lift fluctuations and was acoustically tested at three nozzle sizes for reduced noise generation. The lift fluctuations on the stator were reduced by increasing the stator cord, adjusting incidence angles, and adjusting the rotor velocity diagrams. Broadband noise levels were signficantly reduced in the middle to high frequencies. Blade passage tone sound power was not lessened, but decreases in the harmonics were observed. Aerodynamic improvements in both performance and efficiency were obtained.

Dittmar, J. H.; Woodward, R. P.; Stakolich, E. G.

1977-01-01

32

Experimental results for labyrinth gas seals with honeycomb stators - Comparisons to smooth-stator seals and theoretical predictions  

NASA Technical Reports Server (NTRS)

Experimental measurements are presented for the rotordynamic stiffness and damping coefficients of a teeth-on-rotor labyrinth seal with a honeycomb stator. Inlet circumferential velocity, inlet pressure, rotor speed, and seal clearance are primary variables. Results are compared to data for teeth-on-rotor labyrinth seals with smooth stators and to analytical predictions 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 rator speeds. At high rotor speeds, the stator surface does not affect stability. 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; however, the model predictions and test results diverge with increasing running speed. Overall, the model does not perform as well for low clearance seals as for high clearance seals.

Hawkins, Larry; Childs, Dara; Hale, Keith

1989-01-01

33

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

34

Noise study of single stage compressor rotor-stator interaction  

NASA Technical Reports Server (NTRS)

Study made of noise radiation from rotor-stator interaction in axial-flow compressors. The collected data were reduced to the form of radiation patterns and frequency spectra. These data show how the radiation patterns are affected by the relative number of rotor blades and stator vanes.

Copeland, W. L.; Crigler, J. L.

1967-01-01

35

Signal based fault detection for stator insulation in electric motors  

Microsoft Academic Search

Stator winding insulation damage in induction motors is considered in this research and fault features developed during the artificial aging process of the stator insulation are extracted from the collected data by the spectral analysis methods. Even harmonic effects are determined as a common feature between the phase currents and vibration signals using the coherence analysis and hence this feature

Emine Ayaz; Murat Ucar; Serhat Seker; Belle R. Upadhyaya

2008-01-01

36

Development of small, tapered stator helical magnetic flux compression generators  

Microsoft Academic Search

For some applications of magnetic flux compression generators, shorter pulse widths, with associated higher voltages and power level, are required. We have developed a family of small, tapered stator generators that begin to address these applications. Specifically, the three versions of these FCGs developed use stator angles of 10°, 12°, and 13° with respect to the generator axis. The armature

Bruce L. Freeman; John C. Boydston; Jim M. Ferguson; Brent A. Lindeburg; Alvin D. Luginbill; Teresa E. Tutt

2003-01-01

37

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

38

Motor stator using corner scraps for additional electrical components  

DOEpatents

A method for making a motor and auxiliary devices with a unified stator body comprises providing a piece of material (10) having an area larger than a cross section of the stator (11), removing material from the piece of material (10) to form a pattern for a cross section of a core (11) for the stator, and removing material from the piece of material (10) outside the cross section of the core of the stator (11) to allow positioning of cores (22, 23, 24) for supporting windings (25, 26, 27) of least one additional electromagnetic device, such as a transformer (62) in a dc-to-dc converter (61, 62) that provides a low. voltage dc output. An article of manufacture made according to the invention is also disclosed and apparatus made with the method and article of manufacture are also disclosed.

Hsu, John S.; Su, Gui-Jia; Adams, Donald J.; Nagashima, James M.; Stancu, Constantin; Carlson, Douglas S.; Smith, Gregory S.

2004-03-16

39

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

40

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

41

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

Microsoft Academic Search

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

PA CALVIÑO; HE ECHEVERRÍA

42

Rotor wake/stator interaction noise-predictions versus data  

NASA Astrophysics Data System (ADS)

A rotor wake/stator interaction noise prediction method is presented and evaluated with fan rig and full-scale engine data. The noise prediction method uses a two-dimensional (2D) semi-empirical wake model and an analytical stator response function and noise calculation. The stator response function is a 2D strip theory which is linked to a noise calculation formulated in a constant area annular duct with mean axial flow. Comparisons are made with data from an Advanced Ducted Propeller (ADP) fan rig which is a next-generation turbofan engine design. A calibration of the prediction model is attempted using this rig data. The calibrated model is subsequently utilized to calculate and compare with noise test data from a 4.1-inch diameter fan rig and from a full-scale turbofan engine configuration. The results indicate the method has promise, but that further improvement is desirable.

Topol, D. A.

1990-10-01

43

Stator Flux Oriented Control with Improved Integrator for Speed-Sensorless Induction Motor Drives  

Microsoft Academic Search

This paper presents a speed-sensorless control algorithm for induction motors, based on the stator flux-oriented control. The algorithm has the advantage of insensitivity to rotor parameters and load varying, stator flux and rotor speed is closed loop controlled respectively. The main improvement is that stator flux is estimated based on a modified integrator which is developed to solve the problems

Hao Zhang; Xianzhong Dai

2010-01-01

44

Resistance of the insulation of the stator winding of water-filled submersible electric motor  

Microsoft Academic Search

The authors analyzed the data on the resistance of the insulation of the stator winding of water-filled electric motors obtained in tests of 560 series produced machines in the course of ten years. The stator windings were made of conductors PEVVP and PVDP. The authors conclude that the resistance of the insulation of the stator windings of series produced electric

V. F. Fedorov; O. N. Nikiforova; V. T. Kolesnikova

1987-01-01

45

Forces acting on induction machine stator core due to winding faults  

Microsoft Academic Search

Contents A newly developed model for direct calculation of the Fourier components of currents is presented. Any connection of stator coils including shortings, can be analysed. A formula giving forces acting on the stator has the form of a sum of various waves. The waves causing elliptical deformations of the stator yoke have been specially investigated. The calculation and measurement

W. Rams; J. Rusek; J. Skwarczy?ski

1993-01-01

46

Stator-permanent magnet brushless machines: Concepts, developments and applications  

Microsoft Academic Search

This paper reviews the concepts, developments and applications of the novel permanent magnet brushless machines having magnets and windings in the stator with particular emphasis on operation principles, electromagnetic performance, design and control aspects. The key features of the machines are summarized. Moreover, the recent development and emerging research directions of the machines are also discussed.

Ming Cheng; Wei Hua; Xiaoyong Zhu; Xiangxin Kong; Jianzhong Zhang; Wenxiang Zhao

2008-01-01

47

A thermal cycling type test for generator stator winding insulation  

Microsoft Academic Search

A test has been designed and implemented which cycles the temperature between 40°C and 150°C in about 80 min by the use of circulating currents and cooling air. The test has been successfully used to evaluate the relative performance of similar stator bars made by three different manufacturers. The thermal cycling test was able to duplicate the insulation delamination process

G. C. Stone; J. F. Lyles; J. M. Braun; C. L. Kaul

1991-01-01

48

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

49

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

50

Rotor and stator assembly configured as an aspirating face seal  

NASA Technical Reports Server (NTRS)

A rotor and stator assembly having a rotor and a stator with opposing surfaces defining an air bearing and an air dam of an aspirating face seal. In a first embodiment, the air bearing and the air dam are axially offset. In a second embodiment, the rotor has an axially extending protuberance located radially between the air bearing and the air dam. The axial offset and the protuberance each act to divert the air flow (e.g., compressed gas or combustion gases in a gas turbine or steam in a steam turbine) in a direction transverse to the air flow direction through the air bearing and the air dam, thus isolating the air flows from the air bearing and the air dam which improves seal performance.

Turnquist, Norman Arnold (Inventor); Bagepalli, Bharat Sampathkumaran (Inventor); Reluzco, George (Inventor); Tseng, Wu-Yang (Inventor)

1999-01-01

51

An Inverse Aeroacoustic Problem on Rotor Wake/stator Interaction  

NASA Astrophysics Data System (ADS)

An inverse aeroacoustic model on rotor wake/stator interaction is proposed based on the linearized Euler equations. The sound field is related to the pressure distribution on the stator surface in the form of a Fredholm integral equation of the first kind which is a well-known ill-posed problem. Since the sound field is fully specified, numerical inversion allows the reconstruction of the pressure distribution on the stator surface. For solving the discrete ill-posed problem, the singular-value decomposition technique coupled with the Tikhonov regularization method is applied to stabilize the solution. The optimal regularization parameter is chosen by the generalized cross-validation criterion and the discrete Picard condition is employed to analyze the ill-posedness of the inverse problem. Numerical results show that the reconstruction is fairly good when the signal-to-noise ratio is not very low. The results become inaccurate when the noise dominates over the observer signal. In addition, numerical results also indicate the importance of the reduced frequency. The higher the reduced frequency, the better the reconstruction results.

LUO, J.; LI, X. D.

2002-07-01

52

Influence of vane sweep on rotor-stator interaction noise  

NASA Technical Reports Server (NTRS)

The influence of vane sweep in rotor-stator interaction noise is investigated. In an analytical approach, the interaction of a convected gust representing the rotor viscous wake, with a cascade of cascade of finite span swept airfoils, representing the stator, is analyzed. The analysis is based on the solution of the exact linearized equations of motion. High frequency convected gusts for which noise generation is concentrated near the leading edge of airfoils is considered. In a preliminary study, the problem of an isolated finite span swept airfoil interacting with a convected gust is analyzed. Results indicate that sweep can substantially reduce the farfield noise levels for a single airfoil. Using the single airfoil model, an approximate solution to the problem of noise radiation from a cascade of finite span swept airfoils interacting with a convected gust is derived. A parametric study of noise generated by gust cascade interaction is carried out to assess the effectiveness of vane sweep in reducing rotor-stator interaction noise. The results show that sweep is beneficial in reducing noise levels. Rotor wake twist or circumferential lean substantially influences the effectiveness of vane sweep. The orientation of vane sweep must be chosen to enhance the natural phase lag caused by wake lean, in which case rather small sweep angles substantially reduce the noise levels.

Envia, Edmane; Kerschen, Edward J.

1990-01-01

53

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

54

Study on Control System for Active Magnetic Bearing Considering Motions of Stator  

NASA Astrophysics Data System (ADS)

This paper presents a control system for active magnetic bearings (AMBs) considering the motions of the stator. AMBs require active control for stable support of the rotor. Many control methods for AMBs have been proposed. Most of them are designed with no regard to the stator motions because the stator is usually fixed on the base. However, in some applications, the stator moves with the object in which the AMB is mounted. In this paper, the influences of the stator motions on the relative angle of the rotor to the stator are investigated both theoretically and experimentally. In addition, the signals estimated by a disturbance observer are used to compensate the influences. The influences become remarkable at a low frequency range. The upper side of the remarkable range extends to higher frequency range when the gyroscopic effect is large. The influences are cancelled by the compensation using the observer. The effect of the cancellation depends on the estimation speed of the observer.

Maruyama, Yutaka; Mizuno, Takeshi; Takasaki, Masaya; Ishino, Yuji; Kameno, Hironori; Kubo, Atsushi

55

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

56

Off-design performance loss model for radial turbines with pivoting, variable-area stators  

NASA Technical Reports Server (NTRS)

An off-design performance loss model was developed for variable stator (pivoted vane), radial turbines through analytical modeling and experimental data analysis. Stator loss is determined by a viscous loss model; stator vane end-clearance leakage effects are determined by a clearance flow model. Rotor loss coefficient were obtained by analyzing the experimental data from a turbine rotor previously tested with six stators having throat areas from 20 to 144 percent of design area and were correlated with stator-to-rotor throat area ratio. An incidence loss model was selected to obtain best agreement with experimental results. Predicted turbine performance is compared with experimental results for the design rotor as well as with results for extended and cutback versions of the rotor. Sample calculations were made to show the effects of stator vane end-clearance leakage.

Meitner, P. L.; Glassman, A. J.

1980-01-01

57

Study of controlled diffusion stator blading. 1. Aerodynamic and mechanical design report  

NASA Technical Reports Server (NTRS)

Pratt & Whitney Aircraft is conducting a test program for NASA in order to demonstrate that a controlled-diffusion stator provides low losses at high loadings and Mach numbers. The technology has shown great promise in wind tunnel tests. Details of the design of the controlled diffusion stator vanes and the multiple-circular-arc rotor blades are presented. The stage, including stator and rotor, was designed to be suitable for the first-stage of an advanced multistage, high-pressure compressor.

Canal, E.; Chisholm, B. C.; Lee, D.; Spear, D. A.

1981-01-01

58

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

59

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

60

Loss model for off-design performance analysis of radial turbines with pivoting-vane, variable-area stators  

NASA Technical Reports Server (NTRS)

An off-design performance loss model is developed for variable-area (pivoted vane) radial turbines. The variation in stator loss with stator area is determined by a viscous loss model while the variation in rotor loss due to stator area variation (for no stator end-clearance gap) is determined through analytical matching of experimental data. An incidence loss model is also based on matching of the experimental data. A stator vane end-clearance leakage model is developed and sample calculations are made to show the predicted effects of stator vane end-clearance leakage on performance.

Meitner, P. L.; Glassman, A. J.

1980-01-01

61

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...

62

Novel stator design of fan motors using soft magnetic composites  

NASA Astrophysics Data System (ADS)

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

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

2008-04-01

63

Modelling and Analysis of Dual-Stator Induction Motors  

NASA Astrophysics Data System (ADS)

In this paper, the analysis and the modelling of a Dual-Stator Induction Motor (DSIM) are presented. In particular, the effects of the shift angle between its three-phase windings are studied. A complex steady state model is first established in order to analyse its harmonic behavior when it is supplied by a non-sinusoidal voltage source. Then, a new transformation matrix is proposed to develop a suitable dynamic model. In both cases, the study is made using an arbitrary shift angle. Simulation results of its PWM control are also presented and compared in order to confirm our theoretical observations.

Razik, Hubert; Rezzoug, Abderrezak; Hadiouche, Djafar

64

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

65

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

E-print Network

Numerical modeling of heat transfer and fluid flow in rotor-stator cavities with throughflow S in a rotor-stator cavity subjected to a superimposed throughflow with heat transfer. Nu- merical predictions field from the heat transfer process. The turbulent flux is approximated by a gradient hypothesis

Boyer, Edmond

66

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 on the homopolar component of the generator stator current and attempts to highlight the use of the Ensemble detection of the generator health degeneration, facilitating a proactive response, minimizing downtime

Paris-Sud XI, Université de

67

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

E-print Network

EEMD-based wind turbine bearing failure detection using the generator stator current homopolar detection techniques based on the homopolar component of the generator stator current and attempts. This allows for early detection of the generator health degeneration, facilitating a proactive response

Boyer, Edmond

68

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

69

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

Microsoft Academic Search

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

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

2006-01-01

70

Stator fault analysis based on wavelet technique for wind turbines equipped with DFIG  

Microsoft Academic Search

The paper introduces a monitoring and diagnostic technique for the detection of incipient stator electrical faults in doubly fed induction generators (DFIGs) for wind power systems. Depending on wind speed, the induction machine operates continuously in non stationary conditions. In this context, traditional Fourier Analysis fails to discriminate between healthy and abnormal stator operating conditions. To overcome this limitation a

Y. Gritli; A. Stefani; F. Filippetti; A. Chatti

2009-01-01

71

Development of a stationary partial discharge monitoring system for high-voltage rotating machine stator windings  

Microsoft Academic Search

The stationary partial discharge detector developed by the Bureau of Reclamation provides an economical method of monitoring partial discharge activity in high-voltage motor\\/generator stator windings. No physical connection to the stator coil or winding is required for this monitoring system; therefore, the integrity of the winding insulation is not compromised. The system can be used to monitor partial discharge during

R. C. Arbour; B. Milano

1989-01-01

72

Study on the vibration displacement distribution of a circular ultrasonic motor stator.  

PubMed

In this paper is presented a theoretical consideration on the stator's displacement distribution, which is one of the most important problems in defining the structure of a circular ultrasonic motor stator. The results are compared with ones obtained utilizing a holographic interferometer, a laser vibrometer and FEM (finite element method) simulation. They are in good agreement with each other. PMID:25682296

Ri, Chol-Su; Kim, Myong-Jin; Kim, Chol-Su; Im, Song-Jin

2015-05-01

73

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

74

Rough Design of a Double-Stator Axial Flux Permanent Magnet Generator  

E-print Network

, rim-driven concept, permanent magnet machine, axial flux machine, electromagnetic model, thermal modelRough Design of a Double-Stator Axial Flux Permanent Magnet Generator for a Rim-Driven Marine.s@eca-en.fr Abstract--This paper deals with the rough design of a Double-Stator Axial Flux Permanent Magnet Machine

Paris-Sud XI, Université de

75

An analysis of wake-stator interaction in airfoil cascades  

NASA Astrophysics Data System (ADS)

A computational study has been conducted in order to provide insight into the details of the unsteady flow in the leading-edge region of airfoil cascades during wake-stator interaction. The calculations are performed at off-design operating conditions, since the flow at conditions near to those at which stall onset occurs is of particular interest in helping to understand the mechanisms responsible for compressor stall. A thorough understanding of these mechanisms will provide the underpinnings needed to design compressors with favorable stall characteristics, using fewer design iterations than are typical with the present state of the art. The results obtained during this study show that the use of highly refined grids leads to the resolution of complex unsteady phenomena associated with wake-stator interaction. The structure of the interaction is shown to change significantly as the magnitude of the wake deficit is increased, with shedding from the leading-edge separation bubble suppressed compared to that observed for the cases with small wake deficit or no wake disturbance.

Barnett, M.; Sondak, D. L.

1995-03-01

76

Modeling shrouded stator cavity flows in axial-flow compressors  

SciTech Connect

Experiments and computational analyses were completed to understand the nature of shrouded stator cavity flows. From this understanding, a one-dimensional model of the flow through shrouded stator cavities was developed. This model estimates the leakage mass flow, temperature rise, and angular momentum increase through the cavity, given geometry parameters and the flow conditions at the interface between the cavity and primary flow path. This cavity model consists of two components, one that estimates the flow characteristics through the labyrinth seals and the other that predicts the transfer of momentum due to windage. A description of the one-dimensional model is given. The incorporation and use of the one-dimensional model in a multistage compressor primary flow analysis tool is described. The combination of this model and the primary flow solver was used to reliably simulate the significant impact on performance of the increase of hub seal leakage in a twelve-stage axial-flow compressor. Observed higher temperatures of the hub region fluid, different stage matching, and lower overall efficiencies and core flow than expected could be correctly linked to increased hub seal clearance with this new technique. The importance of including these leakage flows in compressor simulations is shown.

Wellborn, S.R.; Tolchinsky, I.; Okiishi, T.H.

2000-01-01

77

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

NASA Astrophysics Data System (ADS)

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

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

2011-02-01

78

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

Microsoft Academic Search

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

Takashi Maeno; Takayuki Tsukimoto; Akira Miyake

1992-01-01

79

Nanoemulsions produced by rotor-stator high speed stirring.  

PubMed

Nanoemulsions were produced by high speed stirring using an ART MICCRA D27 rotor-stator system. Nanoemulsions with a droplet size of 135nm and a narrow size distribution were obtained. The emulsions are physically stable for at least three months. Optimized production parameters are a stirring speed of 36,000rpm (maximum speed) and a production time of 5min. A further reduction in processing time might be possible with a rotor with ultrafine slit size, i.e., 0.5mm. The droplet size of the emulsion produced by high speed stirring is slightly larger than droplet sizes obtained by high pressure homogenization. However, the differences in size can be expected to have no influence on the in vivo efficacy of the emulsions. Thus, high speed stirring was found to be a highly effective method for the production of nanoemulsions. The process is fast, cost-effective and can be used for large scale production. PMID:25532442

Scholz, Patrik; Keck, Cornelia M

2015-03-30

80

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

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

Single stage evaluation of highly loaded high Mach number compressor stages. 6: Data and performance of cantilevered stator  

NASA Technical Reports Server (NTRS)

A compressor stage with a rotor tip speed of 1600 ft/sec was tested to evaluate its performance with a cantilevered stator and a rotating inner shroud beneath the stator. Both the rotor blades and the stator vanes were composed of multiple circular arc airfoil sections. Comparison of data taken during this test of the cantilevered stator and previous tests with the same compressor and airfoil geometry in a shroud stator configuration showed only slight differences in stage performance with no significant effect on overall efficiency. However, the severity of the stator wake near the rotating hub was decreased at all flows including the near surge condition. Stall and wise open discharge corrected weight flows were the same as for the shrouded stator configuration.

Merrow, A. S.

1972-01-01

83

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

84

Electrical machines and assemblies including a yokeless stator with modular lamination stacks  

DOEpatents

An electrical machine includes a rotor with an inner rotor portion and an outer rotor portion, and a double-sided yokeless stator. The yokeless stator includes modular lamination stacks and is configured for radial magnetic flux flow. The double-sided yokeless stator is concentrically disposed between the inner rotor portion and the outer rotor portion of the electrical machine. Examples of particularly useful embodiments for the electrical machine include wind turbine generators, ship propulsion motors, switch reluctance machines and double-sided synchronous machines.

Qu, Ronghai; Jansen, Patrick Lee; Bagepalli, Bharat Sampathkumar; Carl Jr., Ralph James; Gadre, Aniruddha Dattatraya; Lopez, Fulton Jose

2010-04-06

85

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

86

Surface impedance method applied to the prediction of eddy currents in hydrogenerator stator end regions  

SciTech Connect

A three-dimensional finite-element analysis is employed to investigate the losses of hydrogenerator stator end regions by using surface-impedance boundary conditions. The three-dimensional complexity of the end-winding geometry is fully taken into account by the model. The purpose of this work is also to evaluate the eddy-current paths allowing for slits in the stator teeth and their effectiveness in reducing stator core-end losses. The methodology was applied to the stator core of a 52-pole 300-MVA hydrogenerator in two different cases: (1) with non-slit teeth; (2) with fully slit teeth. It may also be extended to large turbogenerators end regions.

Silva, V.C.; Marechal, Y.; Foggia, A. [URA CNRS 355, Saint-Martin-d`Heres (France). Lab. d`Electrotechnique de Grenoble] [URA CNRS 355, Saint-Martin-d`Heres (France). Lab. d`Electrotechnique de Grenoble

1995-05-01

87

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

88

A comparison of experimental and theoretical results for labyrinth gas seals with honeycomb stators  

E-print Network

) Lawrence Allen Hawkins, B. S. , Auburn University; Chair of Advisory Committee: Dr. Dara Childs 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 also compared to analytical results from a two-control-volume compressible ffow model. The experimental results show that the honeycomb...

Hawkins, Lawrence Allen

1988-01-01

89

Blade-forced vibration effects in turbomachinery rotor-stator interaction  

E-print Network

BLADE-FORCED VIBRATION EFFECTS IN TURBOMACHINERY ROTOR-STATOR INTERACTION A Thesis 3OSEPH EUGENE COLLARD, III Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of thc requirements for the degree...: Aerospace Engineeriug ABSTRACT Blade-Forced Vibration Effects in Turbomachinery Rotor-Stator Interaction. (December 2000) Joseph Eugene Collard, III, B. A. , University of Dallas Chair of Advisory Committee: Dr. Paul G. A. Cizmas This thesis presents...

Collard, Joseph Eugene

2000-01-01

90

Design Selection and Analysis of a Swept and Leaned Stator Concept  

NASA Technical Reports Server (NTRS)

This report describes a theoretical design and analysis study of the benefits of vane sweep and lean for reducing rotor- stator interaction tone noise. It is shown that the kinematic relationship between the rotor wakes and stator vanes is the principal factor in determining the achievable noise reductions. Vane sweep and lean control rotor wake skewing as seen by the stator vanes and hence influence the number of wake intersections per vane. An increase in the number of intersections reduces noise levels. Hence, to reduce rotor-stator noise, van sweep and lean must be chosen in such a way as to increase wake intersections per vane. A simple design rule is thus proposed which requires a sweep configuration that puts the vane tip downstream of its root and a vane lean that is in the direction of the rotor rotation. A detailed comparison of the predicted and measured noise reductions for a swept and leaned stator is then carried out. Overall, these comparisons show that the predicted benefits of a swept and leaned stator are in good agreement, qualitative as well as quantitative, with the measured reductions for the fan speeds relevant to noise certification procedure. Furthermore, the results also demonstrate the validity of design criterion and the theoretical tools used in this study.

Envia, Edmane; Nallasamy, M.

1998-01-01

91

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

92

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

PubMed

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

Koyama, Daisuke; Nakamura, Kentaro; Ueha, Sadayuki

2007-11-01

93

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

94

Finite element simulation for a new disc-type ultrasonic stator.  

PubMed

This paper is concerned with the development of a new disc-type piezoelectric ultrasonic stator. Linear piezoelectric, mechanical, and piezoelectro-mechanic behaviors of a metal disc structure embedded with piezoelectric actuator are considered. Using a finite element method, a dynamic formulary is modeled for the new disc-type piezoelectric ultrasonic stator. In this model, a 3-dimensional (D) mechanical element with an extra electrical degree of freedom is used to simulate dynamic vibration modes and analyze characteristic responses such as electrical impedance response, phase response, and mechanical frequency response for a new disc-type piezoelectric ultrasonic stator. An adaptive boundary condition, simple support condition with three nonequal-triangular fixed points near the edge for the mechanism design of a new disc-type piezoelectric ultrasonic stator is defined so that a lateral elliptical motion of the contact point between stator and rotor can be realized for driving the rotor. The finite element results have been compared with the experimental measurements. As a result, the analysis model seems to be similar to the real condition. PMID:12744392

Juang, Puu-An; Gu, Da-Wei

2003-04-01

95

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

96

Extension of Useful Operating Range of Axial-Flow Compressors by Use of Adjustable Stator Blades  

NASA Technical Reports Server (NTRS)

A theory has been developed for resetting the blade angles of an axial-flow compressor in order to improve the performance at speeds and flows other than the design and thus extend the useful operating range of the compressor. The theory is readily applicable to the resetting of both rotor and stator blades or to the resetting of only the stator blades and is based on adjustment of the blade angles to obtain lift coefficients at which the blades will operate efficiently. Calculations were made for resetting the stator blades of the NACA eight-stage axial-flow compressor for 75 percent of design speed and a series of load coefficients ranging from 0.28 to 0.70 with rotor blades left at the design setting. The NACA compressor was investigated with three different blade settings: (1) the design blade setting, (2) the stator blades reset for 75 percent of design speed and a load coefficient of 0.48, and (3) the stator blades reset for 75 percent of design speed and a load coefficient of 0.65.

Sinnette, John T; Voss, William J

1948-01-01

97

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

98

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

99

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

Microsoft Academic Search

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

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

2000-01-01

100

An experimental and computational investigation on the effects of stator leakage flow on compressor performance  

NASA Astrophysics Data System (ADS)

Engineers are relying more on computational predictions to aid in the design of multistage compressors. As compressor designs advance to more sophisticated geometries with higher loadings, the predictive tools must be able to capture the effects on secondary flows, those flows not associated with the main compressor through flow. In the rear stages of a compressor where aspect ratios are low, secondary flows associated with endwall boundary layers and shrouded stator leakage flow must be understood. The objective of this research was to investigate the effects of stator leakage flow on compressor performance. All experimental research was conducted at the Purdue 3-Stage Axial Compressor Research Facility. The axial compressor is a scaled-up representation of the rear stages of a high pressure compressor with engine representative Mach numbers and Reynolds numbers. Computational research was conducted using a steady RANS CFD code with multiple meshes to investigate the sensitivity of computational modeling to stator leakage cavities. Facility specific boundary conditions were acquired experimentally and applied to the computational models. Detailed total pressure and total temperature measurements indicate that the inlet of the compressor is circumferentially uniform allowing for an axisymmetric boundary condition to be applied to both experimental and computational research. The shrouded stator cavity in the third stage of the compressor is open to ambient conditions. Mass flow rate through this cavity is measured using an orifice flow meter, and the cavity can be plugged to prevent any leakage flow. Static pressure measurements were acquired at the exit of the stator 3 cavity so that the leakage flow could be simulated and compared with experimental data. Radial total pressure profiles predicted by the different numerical models are compared with experimental profiles with the cavity open and plugged. The predicted compressor performance at high flow conditions was strongly dependent upon the particular leakage flow model employed. Physically meshing the stator cavities yielded the best comparison of overall performance predictions and radial profiles to experimental data near design loading. Since plugging the stator 3 cavity yielded only small changes in the radial total pressure profile, experimental and computational data suggest the leakage flow through the stator 3 cavity on the Purdue 3-Stage Axial Compressor has a relatively negligible impact on overall compressor and stage-by-stage performance.

Ball, Patrick Ryan

101

Determination of optimum geometrical parameters of stators of turbine expansion engines  

SciTech Connect

The efficiency of the stators of centripetal radial turbine expansion engines, characterized by the small dimensions of the flow section have been studied. The study is extended to obtain data on the variation of the losses in relation to the relative geometrical parameters. Investigations have been carried out into the level of the total losses in the wing-shaped small vane stator and its geometrical parameters are optimized. The processing method accepted for the calculations is based on the equations of the unidimensional theory of the gas flows which gives sufficiently reliable results.

Sherstyuk, A.N.; Davydov, A.B.; Rozenoer, T.M.; Vasil'ev, M.Y.

1986-05-01

102

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

103

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

104

Cold-air investigation of a turbine for high temperature-engine application. 5: Two-stage turbine performance as affected by variable stator area  

NASA Technical Reports Server (NTRS)

The stator areas of the design two-stage turbine were both decreased and increased by nominally 30 percent, and the performances of the two turbines are compared with that of the design stator area turbine. Turbine efficiency decreased with stator area changes. Closing the stator area resulted in the more severe efficiency loss. The decrease in efficiency for both turbines is attributable to rotor incidence, off-design blade-surface velocities, and adverse reaction changes across the blade rows.

Behning, F. P.; Schum, H. J.; Szanca, E. M.

1974-01-01

105

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

106

System and method for monitoring and controlling stator winding temperature in a de-energized AC motor  

DOEpatents

A system and method for measuring and controlling stator winding temperature in an AC motor while idling is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of a multi-phase AC motor. The circuit further includes a plurality of switching devices to control current flow and terminal voltages in the multi-phase AC motor and a controller connected to the circuit. The controller is configured to activate the plurality of switching devices to create a DC signal in an output of the motor control device corresponding to an input to the multi-phase AC motor, determine or estimate a stator winding resistance of the multi-phase AC motor based on the DC signal, and estimate a stator temperature from the stator winding resistance. Temperature can then be controlled and regulated by DC injection into the stator windings.

Lu, Bin (Kenosha, WI); Luebke, Charles John (Sussex, WI); Habetler, Thomas G. (Snellville, GA); Zhang, Pinjia (Atlanta, GA); Becker, Scott K. (Oak Creek, WI)

2011-12-27

107

Effects of blade-vane ratio and rotor-stator spacing of fan noise with forward velocity  

NASA Technical Reports Server (NTRS)

A research fan stage was acoustically tested in an anechoic wind tunnel with a 41 m/sec tunnel flow. Two stator vane numbers giving cut-on and cut-off conditions were tested at three rotor-stator spacings ranging from about 0.5 to 2.0 rotor chords. These two stators were designed for similar aerodynamic performance. Hot film anemometer turbulence measurements were made at the leading edge of the stator for each spacing. The cut-off criterion strongly controlled the fundamental tone level at all spacings. The trends with spacing of the wake defect upwash component at the stator tip showed good agreement with the corresponding cut-on acoustic tone levels.

Woodward, R. P.; Glaser, F. W.

1981-01-01

108

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

109

Stator current and power factor optimization in an IPMSM for railway traction application  

Microsoft Academic Search

The objective of this paper is to compare two control strategies aimed at optimizing stator current and power factor in the constant torque operation zone on railway traction applications when interior permanent magnet synchronous machines (IPMSM) are used. Both control strategies are the classical “zero d-current”, which is used in most of industrial applications, and the Most Torque per Amp

A. Lopez-de-Heredia; C. Calleja; A. Lertxundi; A. Aranburu; T. Nieva

2011-01-01

110

Stochastic Modeling of Soft Magnetic Properties of Electrical Steels: Application to Stators of Electrical Machines  

E-print Network

1 Stochastic Modeling of Soft Magnetic Properties of Electrical Steels: Application to Stators of the electrical steel sheet depends on the mechanical stress and the direction of the magnetic field excitation of Electrical Machines R.Ramarotafika1,2 , A.Benabou2 , S.Clénet1 1 L2EP/Arts et Métiers ParisTech, Centre de

Paris-Sud XI, Université de

111

Dynamic pressure and shear stress measurements on the stator wall of whirling annular seals  

E-print Network

Dynamic pressure and shear stress measurements on the stator wall of whirling annular seals are presented. Two flow conditions (Re=12,000 & 24,000), two seal speeds (Ta=3,300 & 6,600) and three eccentricity ratios (0, 10, & 50% of the clearance...

Winslow, Robert Bradley

1994-01-01

112

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

113

Partial discharges in stator winding insulation of turbine generators — A case study and remedies  

Microsoft Academic Search

Development of partial discharge (PD) detection methods by A\\/D conversion has acquired very important place in diagnosis for healthiness assessment of dielectric insulation of stator windings in turbine generators (TG). Evaluation of acquired digital spectrum for characteristics of PDs of the machine is the critical aspect in PD analysis. This paper describes the method of detecting PDs in (TG) high

P. G. S. Kumar; J. Amarnath; B. P. Singh

2011-01-01

114

Quantification of flagellar motor stator dynamics through in vivo proton-motive force control  

E-print Network

different genes (Macnab, 2003). In Escherichia coli, the motor drives rota- tion of a flagellar apparatus on the motor was calculated to be 0.06 s-1 . Using GFP-tagged MotB stator proteins, we found that tran- sient the swimming cell. Flagellar motors are driven by ion-motive forces (IMFs): the E. coli motor, among others

Berry, Richard

115

A Parametric Study of Unsteady Rotor-Stator Interaction in a Simplified Francis Turbine  

NASA Astrophysics Data System (ADS)

CFD analysis is becoming a critical stage in the design of hydroturbines. However, its capability to represent unsteady flow interactions between the rotor and stator (which requires a 360-degree, mesh-refined model of the turbine passage) is hindered. For CFD to become a more effective tool in predicting the performance of a hydroturbine, the key interactions between the rotor and stator need to be understood using current numerical methods. As a first step towards evaluating this unsteady behavior without the burden of a computationally expensive domain, the stator and Francis-type rotor blades are reduced to flat plates. Local and global variables are compared using periodic, semi-periodic, and 360-degree geometric models and various turbulence models (k-omega, k-epsilon, and Spalart-Allmaras). The computations take place within the OpenFOAM^ environment and utilize a general grid interface (GGI) between the rotor and stator computational domains. The rotor computational domain is capable of dynamic rotation. The results demonstrate some of the strengths and limitations of utilizing CFD for hydroturbine analysis. These case studies will also serve as tutorials to help others learn how to use CFD for turbomachinery.

Wouden, Alex; Cimbala, John; Lewis, Bryan

2011-11-01

116

Study of a Flow Control System in a High Turning Stator Cascade Using Dpiv  

Microsoft Academic Search

A flow control system for a high turning stator cascade was investigated using Particle Image Velocimetry (PIV) and conventional pressure instrumentation. The system consists of small blowing cavities and suction holes in the blades. Experiments were performed in the transonic blowdown wind tunnel of Virginia Tech for various Mach numbers, cascade angles, and blowing and suction ratios. The results show

Jordi Estevadeordal; William Copenhaver; Wing Ng; Casey Carter

2001-01-01

117

Application of Tandem Cascade to Design of Fan Stator with Supersonic Inflow  

Microsoft Academic Search

This article proposes a tandem cascade constructed to tackle the thorny problem of designing the high-loaded stator with a supersonic inflow and a large turning angle. The front cascade adopts a supersonic profile to reduce the shock wave intensity turning the flow into subsonic, while the rear cascade adopts a subsonic profile with a large camber offering the flow a

Li Qiushi; Wu Hong; Zhou Sheng

2010-01-01

118

Local convective heat transfer for laminar and turbulent flow in a rotor-stator system  

NASA Astrophysics Data System (ADS)

The aim of this work is to show a better comprehension of the flow structure and thermal transfer in a rotor-stator system with a central opening in the stator and without an airflow imposed. The experimental technique uses infrared thermography to measure the surface temperatures of the rotor and the numerical solution of the steady-state heat equation to determine the local heat transfer coefficients. Analysis of the flow structure between the rotor and the stator is conducted by PIV. Tests are carried out for rotational Reynolds numbers ranging from 5.87×104 to 1.4×106 and for gap ratios ranging from 0.01 to 0.17. Analysis of the experimental results has determined the influence of the rotational Reynolds number, the gap ratio and system’s geometry on the flow structure, and the convective exchanges in the gap between the rotor and the stator. Some correlations expressing the local Nusselt number as a function of the rotational Reynolds number and the gap ratio are proposed.

Boutarfa, Rachid; Harmand, Souad

2005-02-01

119

PROPULSOR THRUST VECTORING THROUGH STATOR-INDUCED CIRCUMFERENTIALLY-VARYING PRESWIRL  

E-print Network

maneuvering and stealthy propulsion system for torpedoes and unmanned underwater vehicles. The idea would on the vehicle. This novel control system would have several potential applications. Most notably, in torpedoes: Displays the aft torpedo section previously tested by NUWC showing the stator array upstream

Salama, Khaled

120

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

121

A survey of testing and monitoring methods for stator insulation systems in induction machines  

Microsoft Academic Search

A breakdown of the electrical insulation system causes catastrophic failure of the electrical machine and brings large process downtime losses. To determine the conditions of the stator insulation system of motor drive systems, various testing and monitoring methods have been developed. This paper presents an in-depth literature review of more than 20 existing methods, including the most common methods to

S. Grubic; J. M. Aller; B. Lu; T. G. Habetler

2008-01-01

122

Temperature measurement in a turbine stator assembly using an integratable high-temperature ultrasonic sensor network  

NASA Astrophysics Data System (ADS)

Implementation of an integratable ultrasonic sensor network with associated cable connection for high temperature monitoring applications is demonstrated through application of a three-element ultrasonic sensor network for temperature measurement in a turbine stator assembly. The sensor network is composed of a piezoelectric composite film deposited on a titanium substrate with a sol-gel technique and three top electrodes deposited on the piezoelectric film. The sensor network is glued onto a selected area of the stator assembly in such a way that three subareas with different wall thicknesses are probed individually by each of the sensing elements. The ultrasonically instrumented stator assembly is first heated in a furnace to different temperatures. At each temperature and for each probed location the transit time of ultrasonic waves through assembly wall thickness is measured. Then a relationship between transit time and wall temperature is established. In a subsequent experiment, the stator assembly is heated up to 200 °C and then let cool down while the transit time in the assembly wall is being measured continuously. By using the transit time versus temperature relationship obtained earlier, the heating and cooling rates at the three probed locations are determined and then compared.

Wu, Kuo-Ting; Sun, Zhigang; Kobayashi, Makiko; Galeote, Brian; Mrad, Nezih

2011-04-01

123

Comparative analysis of Double Stator Switched Reluctance Machine and Permanent Magnet Synchronous machine  

Microsoft Academic Search

High torque density Permanent Magnet machine are widely used in practice. However, the rising cost of high energy rare earth permanent magnet material stimulates the needs for electrical machines using less or no permanent magnet. Double Stator Switched Reluctance Machine is a novel high torque density reluctance machine. This paper provides a comparison between surface mount Permanent Magnet Synchronous Machine

Wei Wang; Chenjie Lin; Babak Fahimi

2012-01-01

124

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

E-print Network

Flagella stator homologs function as motors for myxobacterial gliding motility by moving in helical characterized the dynamics of the Myxococcus xanthus gliding motor protein AglR, a homolog of the Escherichia, accumulating in clus- ters. Our work shows that the untethered gliding motors of M. xanthus, by moving within

Yildiz, Ahmet

125

Harmonic Analysis of a Short Stator Linear Induction Machine Using a Transformation Technique  

Microsoft Academic Search

An analysis method is introduced for the short stator linear induction machine with homogeneous conducting rotor. The method incorporates harmonic rotor currents and a coordinate transformation into a modified Lagrangian formulation of the equations of motion. These equations permit both excitation and ferromagnetic edge effects as well as skin effects to be accounted for.

G. G. North

1973-01-01

126

Performance analysis of double-stator starter generator for the hybrid electric vehicle  

Microsoft Academic Search

In accordance with the installation characteristics of the starter generator (SG) system in the hybrid electric vehicle (HEV), a design of the flat structure double-stator permanent magnet (PM) brushless electric machine is presented in this paper. Four feasible structure styles are introduced; the merits and the defects of each structure are analyzed and compared. Electromagnetic field finite element method (FEM)

Chai Feng; Shumei Cui; Chengshu Kang

2004-01-01

127

Two Redundant Sodium-Driven Stator Motor Proteins Are Involved in Aeromonas hydrophila Polar Flagellum Rotation?  

PubMed Central

Motility is an essential characteristic for mesophilic Aeromonas strains. We identified a new polar flagellum region (region 6) in the A. hydrophila AH-3 (serotype O34) chromosome that contained two additional polar stator genes, named pomA2 and pomB2. A. hydrophila PomA2 and PomB2 are highly homologous to other sodium-conducting polar flagellum stator motors as well as to the previously described A. hydrophila AH-3 PomA and PomB. pomAB and pomA2B2 were present in all the mesophilic Aeromonas strains tested and were independent of the strains' ability to produce lateral flagella. Unlike MotX, which is a stator protein that is essential for polar flagellum rotation, here we demonstrate that PomAB and PomA2B2 are redundant sets of proteins, as neither set on its own is essential for polar flagellum motility in either aqueous or high-viscosity environments. Both PomAB and PomA2B2 are sodium-coupled stator complexes, although PomA2B2 is more sensitive to low concentrations of sodium than PomAB. Furthermore, the level of transcription in aqueous and high-viscosity environments of pomA2B2 is reduced compared to that of pomAB. The A. hydrophila AH-3 polar flagellum is the first case described in which two redundant sodium-driven stator motor proteins (PomAB and PomA2B2) are found. PMID:19181813

Wilhelms, Markus; Vilches, Silvia; Molero, Raquel; Shaw, Jonathan G.; Tomás, Juan M.; Merino, Susana

2009-01-01

128

Numerical investigation of the superimposed effects on stator wake oscillation in an axial-radial combined compressor  

NASA Astrophysics Data System (ADS)

The superimposed influences of the blade rows in a multistage compressor are important because different matches of upstream and downstream blades can result in significant differences in the stator wake oscillation. Numerical investigation of the axial stator wake oscillation, which is affected upstream by the axial rotor and downstream by the radial rotor, was performed in an axial-radial combined compressor. Many configurations with different blade numbers and locations, which influence axial stator wake oscillation were investigated. When rotors have equal blade numbers, the axial stator wake oscillates periodically versus time within time T (moving blade passing 1/3 revolution). In contrast, stator wake oscillates irregularly within T when rotors have different blade numbers. A model-split subtraction method is presented in order to separate the influences of the individual blade rows on the wake oscillation of the axial stator. Analysis from the rotor-stator configuration showed that the unsteady flow angle fluctuation response is caused by the upstream rotor. For the rotor-stator-rotor configuration, the unsteady flow angle fluctuations are influenced by up- and downstream blade rows. With the model-split subtraction method, the up- and downstream influences on the flow angle fluctuation could be clearly separated and quantified. Low amplitudes could be observed when the influences from up- and downstream moving rows were superimposed with the "positive peak-negative peak" type wave. Clocking investigations were carried out to change the relative superimposed phase of influences from the surrounding blade rows in order to modulate the amplitudes of the axial stator wake oscillation. However, the amplitudes did not reach the maximum when they were superimposed with "positive peak-positive peak" type wave due to the impact of the interaction between the two moving blade rows.

Zhao, Ben; Yang, Ce; Hu, Liangjun; Zhou, Mi; Zhang, Jizhong

2014-02-01

129

Performance of a high-work, low-aspect-ratio turbine stator tested with a realistic inlet radial temperature gradient  

NASA Technical Reports Server (NTRS)

A 0.767-scale model of a turbine stator designed for the core of a high-bypass-ratio aircraft engine was tested with uniform inlet conditions and with an inlet radial temperature profile simulating engine conditions. The principal measurements were radial and circumferential surveys of stator-exit total temperature, total pressure, and flow angle. The stator-exit flow field was also computed by using a three-dimensional Navier-Stokes solver. Other than temperature, there were no apparent differences in performance due to the inlet conditions. The computed results compared quite well with the experimental results.

Stabe, Roy G.; Schwab, John R.

1991-01-01

130

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

131

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

132

Conformational change in the periplamic region of the flagellar stator coupled with the assembly around the rotor  

PubMed Central

The torque of the bacterial flagellum is generated by the rotor–stator interaction coupled with the ion flow through the channel in the stator. Anchoring the stator unit to the peptidoglycan layer with proper orientation around the rotor is believed to be essential for smooth rotation of the flagellar motor. The stator unit of the sodium-driven flagellar motor of Vibrio is composed of PomA and PomB, and is thought to be fixed to the peptidoglycan layer and the T-ring by the C-terminal periplasmic region of PomB. Here, we report the crystal structure of a C-terminal fragment of PomB (PomBC) at 2.0-Å resolution, and the structure suggests a conformational change in the N-terminal region of PomBC for anchoring the stator. On the basis of the structure, we designed double-Cys replaced mutants of PomB for in vivo disulfide cross-linking experiments and examined their motility. The motility can be controlled reproducibly by reducing reagent. The results of these experiments suggest that the N-terminal disordered region (121–153) and following the N-terminal two-thirds of ?1(154-164) in PomBC changes its conformation to form a functional stator around the rotor. The cross-linking did not affect the localization of the stator nor the ion conductivity, suggesting that the conformational change occurs in the final step of the stator assembly around the rotor. PMID:25197056

Zhu, Shiwei; Takao, Masato; Li, Na; Sakuma, Mayuko; Nishino, Yuuki; Homma, Michio; Kojima, Seiji; Imada, Katsumi

2014-01-01

133

Experimental rotordynamic coefficient results for teeth-on-rotor and teeth-on-stator labyrinth gas seals  

NASA Technical Reports Server (NTRS)

An experimental test facility is used to measure the rotordynamic coefficients of teeth-on-rotor and teeth-on-stator labyrinth gas seals. Direct damping coefficients are presented for these seals for the first time. The results are presented for the two seal configurations at identical operating conditions, and show that, in a rotordynamic sense, the teeth-on-stator seal is more stable than the teeth-on-rotor seal, for inlet tangential velocity in the direction of rotation.

Childs, D. W.; Scharrer, J. K.

1986-01-01

134

Experimental rotordynamic coefficient results for teeth-on-rotor and teeth-on-stator labyrinth gas seals  

NASA Technical Reports Server (NTRS)

An experimental test facility is used to measure the rotordynamic coefficients of teeth-on-rotor and teeth-on-stator labyrinth gas seals. Direct damping coefficients are presented for these seals for the first time. The results are presented for the two seal configurations at identical operating conditions, and show that, in a rotordynamic sense, the teeth-on-stator seal is more stable than the teeth-on-rotor seal, for inlet tangential velocity in the direction of rotation.

Childs, Dara W.; Scharrer, Joseph K.

1987-01-01

135

On the Stator Slot Geometry of a Cable Wound Generator for Hydrokinetic Energy Conversion  

PubMed Central

The stator slot geometry of a cable wound permanent magnet synchronous generator for hydrokinetic energy conversion is evaluated. Practical experience from winding two cable wound generators is used to propose optimized dimensions of different parts in the stator slot geometry. A thorough investigation is performed through simulations of how small geometrical changes alter the generator performance. The finite element method (FEM) is used to model the generator and the simulations show that small changes in the geometry can have large effect on the performance of the generator. Furthermore, it is concluded that the load angle is especially sensitive to small geometrical changes. A new generator design is proposed which shows improved efficiency, reduced weight, and a possibility to decrease the expensive permanent magnet material by almost one-fifth.

Grabbe, Mårten; Leijon, Mats

2015-01-01

136

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

NASA Astrophysics Data System (ADS)

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

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

2008-04-01

137

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

DOEpatents

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

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

2011-05-31

138

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

139

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

140

Bearing fault detection for direct-drive wind turbines via stator current spectrum analysis  

Microsoft Academic Search

Bearing faults constitute a significant portion of all faults in wind turbine generators (WTGs). Current-based bearing fault detection has significant advantages over traditional vibration-based methods in terms of cost, implementation, and system reliability. This paper proposes a method based on stator current power spectral density (PSD) analysis for bearing fault detection of direct-drive WTGs. In the proposed method, appropriate interpolation\\/up-sampling

Xiang Gong; Wei Qiao

2011-01-01

141

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

Microsoft Academic Search

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

Valter Lovati; Mario Marchesoni; Maurizio Oberti; Paolo Segarich

1998-01-01

142

Laser Doppler, velocimeter system for turbine stator cascade studies and analysis of statistical biasing errors  

NASA Technical Reports Server (NTRS)

A laser Doppler velocimeter (LDV) built for use in the Lewis Research Center's turbine stator cascade facilities is described. The signal processing and self contained data processing are based on a computing counter. A procedure is given for mode matching the laser to the probe volume. An analysis is presented of biasing errors that were observed in turbulent flow when the mean flow was not normal to the fringes.

Seasholtz, R. G.

1977-01-01

143

Incipient bearing fault detection via wind generator stator current and wavelet filter  

Microsoft Academic Search

Bearing faults constitute a significant portion of all faults in rotating machines, including wind turbine generators (WTGs). Current-based bearing fault detection has significant advantages over traditional vibration-based methods in terms of cost, implementation, and system reliability. This paper proposes a new wavelet filter-based method for incipient bearing fault detection using electric machine stator currents. The proposed method can dramatically increase

Xiang Gong; Wei Qiao; Wei Zhou

2010-01-01

144

Performance analysis of double-stator starter generator for the hybrid electric vehicle  

Microsoft Academic Search

In accordance with the installation characteristics of the starter generator (SG) system in the hybrid electric vehicle (HEV), a design of the flat structure double-stator permanent-magnet (PM) brushless electric machine is presented in this paper. Four feasible structure styles are introduced; the merits and the defects of each structure are analyzed and compared. Electromagnetic field finite-element method (FEM) and experimental

Feng Chai; Shumei Cui; Shukang Cheng

2005-01-01

145

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

146

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

147

Single Pass Drop Size Distributions in an Inline Rotor-Stator Mixer  

NASA Astrophysics Data System (ADS)

Rotor-stator mixers are employed to produce liquid-liquid dispersions. Despite their importance, there have been few studies that examine the fundamentals governing dispersion processes occurring in them. We have developed a technique to measure single pass drop size distributions (DSD) exiting an inline rotor-stator device. A continuous, turbulent water phase is fed to the mixer. At time zero, a single drop of oil is injected into the device, and the resulting daughter DSD is measured at the exit via Phase Doppler Anemometry. Bivariate statistics of drop size and residence time are obtained. Results indicate that, for the operating conditions studied, lower viscosity fluids have a bimodal distribution, with a shift towards a monomodal distribution at higher RPM or decreased throughput. More viscous fluids exhibit a monomodal distribution and a shift towards a bimodal distribution at higher RPM's and decreased throughput. Turbulent RANS CFD simulations are being performed in order to assist in interpretation of experimental data. Preliminary results indicate that bimodal distributions may be the result of droplet reentrainment into the stator and / or a large spread in the internal time distributions that drops spend in the region close to the rotor blade.

Kevala, Karl

2005-11-01

148

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

149

Periodic transition on an axial compressor stator: Incidence and clocking effects. Part 1: Experimental data  

SciTech Connect

Periodic wake-induced transition on the outlet stator of a 1.5-stage axial compressor is examined using hot-film arrays on both the suction and pressure surfaces. The time-mean surface pressure distribution is varied by changing the blade incidence, while the free-stream disturbance field is altered by clocking of the stator relative to an inlet guide vane row. Ensemble-averaged plots of turbulent intermittency and relaxation factor (extent of calmed flow following the passage of a turbulent spot) are presented. These show the strength of periodic wake-induced transition phenomena to be significantly influenced by both incidence and clocking effects. The nature and extent of transition by other modes (natural, bypass, and separated flow transition) are altered accordingly. Leading edge and midchord separation bubbles are affected in a characteristically different manner by changing free-stream periodicity. There are noticeable differences between suction and pressure surface transition behavior, particularly as regards the strength and extent of calming. In Part 2 of this paper, the transition onset observations from the compressor stator are used to evaluate the quasi-steady application of conventional transition correlations to predict unsteady transition onset on the blading of an embedded axial compressor stage.

Walker, G.J.; Hughes, J.D. [Univ. of Tasmania, Hobart (Australia). School of Engineering; Solomon, W.J. [Ohio Aerospace Institute/General Electric Aircraft Engines, Cincinnati, OH (United States)

1999-07-01

150

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

151

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

NASA Astrophysics Data System (ADS)

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

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

2010-09-01

152

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

153

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

154

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 material, 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 (HTS) 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 kW (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 kW (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. [Univ. of Tennessee, Knoxville, TN (United States)

1994-12-31

155

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

156

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

157

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

158

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

NASA Astrophysics Data System (ADS)

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

Hamabe, K.; Ishida, K.

1992-06-01

159

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

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

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

162

Method for the determination of the three dimensional aerodynamic field of a rotor-stator combination in compressible flow  

NASA Technical Reports Server (NTRS)

Using the lifting surface theory and the acceleration potential method for the flow field of an axial turbocompressor stage, a recursive and a direct method are presented that make use of the eigenfunction solutions of the isolated rotor and stator to solve for the rotor-stator interaction problem. The net pressure distribution on the rotor and stator blades is represented by modified Birnbaum series, whose coefficients are determined using a matrix procedure and satisfying the boundary conditions on the surface of the blades. The relation between the matrix operators of the recursive and the direct methods is also shown. Expressions have been given for the blade circulation, the axial and tangential forces on the blade, the rotor power required, and the induced upwash velocity of the stage.

Ramachandra, Sridhar M.; Bober, Lawrence J.; Khandelwal, Suresh

1987-01-01

163

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

PubMed

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

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

2013-11-18

164

Combined fringe and Fabry-Perot laser anemometer for three component velocity measurements in turbine stator cascade facility  

NASA Technical Reports Server (NTRS)

A laser anemometer is described that was developed for use in a 508 mm diameter annular turbine stator cascade facility. All three velocity components are measured through a single restricted optical port, both within the stator vane row and downstream of the vanes. The measurements are made through a cylindrical window in the casing that matches the tip radius of the cascade. The stator tested has a contoured hub endwall that results in a large radial flow near the hub. The anemometer uses a standard fringe configuration (LFA) with a fluorescent aerosol seed to measure the axial and circumferential velocity components. The radial component is measured with a confocal Fabry-Perot interferometer. The two configurations are combined in a single optical system and can operate simultaneously. Data are presented to illustrate the capabilities of the system.

Seasholtz, R. G.; Goldman, L. J.

1986-01-01

165

Method for the determination of the three-dimensional aerodynamic field of a rotor-stator combination to compressible flow  

NASA Technical Reports Server (NTRS)

Using the lifting surface theory and the acceleration potential method for the flow field of an axial turbocompressor stage, a recursive and a direct method are presented that make use of the eigenfunction solutions of the isolated rotor and stator to solve for the rotor-stator interaction problem. The net pressure distribution on the rotor and stator blades is represented by modified Birnbaum series, whose coefficients are determined using a matrix procedure and satisfying the boundary conditions on the surface of the blades. The relation between the matrix operators of the recursive and the direct methods is also shown. Expressions have been given for the blade circulation, the axial and tangential forces on the blade, the rotor power required, and the induced upwash velocity of the stage.

Ramachandra, Sridhar M.; Bober, Lawrence J.; Khandelwal, Suresh

1987-01-01

166

Experimental verification and analytical approach to influence stator skew on electromagnetic performance of permanent magnet generators with multipole rotor  

NASA Astrophysics Data System (ADS)

This paper deals with experimental verification and analytical approach to influence stator skew on electromagnetic performance of a permanent magnet generator (PMG) with multipole rotor. The analytical expressions for magnetic field distributions are due to permanent magnets and the two-dimensional permeance function considering skew effects are established. On the basis of these analytical solutions, the analytical solutions for cogging torque and back-emf considering skew effects are also derived. Then, by applying estimated electrical parameters to a simple equivalent circuit of one phase for the PMG, output performances of the PMG with/without a skewed stator are investigated. Finally, by confirming that all analytical results are validated extensively by nonlinear finite element calculations and measurements, the validity of analysis methods presented in this paper is verified, and the influence stator skew on cogging torque, back-emf, and output performances of the PMG is also clearly described.

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

2009-04-01

167

3-D FEM analysis of a novel structure for axial-flux homopolar generators using a grain-oriented silicon steel stator core  

Microsoft Academic Search

In this paper, a novel structure for axial-flux generators in automotive applications is presented. The machine has a field winding in the inner part of the stator core around the rotor shaft. Because of unidirectional magnetic flux in the stator, the generator behaves as a homoploar machine. For better utilization of the generator, grain oriented silicon steel laminations are used

S. Javadi; M. Mirsalim; J. Sabzivand

2008-01-01

168

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

169

Advanced single permanent magnet axipolar ironless stator ac motor for electric passenger vehicles  

NASA Technical Reports Server (NTRS)

A program was conducted to design and develop an advanced-concept motor specifically created for propulsion of electric vehicles with increased range, reduced energy consumption, and reduced life-cycle costs in comparison with conventional systems. The motor developed is a brushless, dc, rare-earth cobalt, permanent magnet, axial air gap inductor machine that uses an ironless stator. Air cooling is inherent provided by the centrifugal-fan action of the rotor poles. An extensive design phase was conducted, which included analysis of the system performance versus the SAE J227a(D) driving cycle. A proof-of-principle model was developed and tested, and a functional model was developed and tested. Full generator-level testing was conducted on the functional model, recording electromagnetic, thermal, aerodynamic, and acoustic noise data. The machine demonstrated 20.3 kW output at 1466 rad/s and 160 dc. The novel ironless stator demonstated the capability to continuously operate at peak current. The projected system performance based on the use of a transistor inverter is 23.6 kW output power at 1466 rad/s and 83.3 percent efficiency. Design areas of concern regarding electric vehicle applications include the inherently high windage loss and rotor inertia.

Beauchamp, E. D.; Hadfield, J. R.; Wuertz, K. L.

1983-01-01

170

Heat production in the windings of the stators of electric machines under stationary condition  

NASA Astrophysics Data System (ADS)

In electric machines due to high currents and resistive losses (joule heating) heat is produced. To avoid damages by overheating the design of effective cooling systems is required. Therefore the knowledge of heat sources and heat transfer processes is necessary. The purpose of this paper is to illustrate a good and effective calculation method for the temperature analysis based on homogenization techniques. These methods have been applied for the stator windings in a slot of an electric machine consisting of copper wires and resin. The key quantity here is an effective thermal conductivity, which characterizes the heterogeneous wire resin-arrangement inside the stator slot. To illustrate the applicability of the method, the analysis of a simplified, homogenized model is compared with the detailed analysis of temperature behavior inside a slot of an electric machine according to the heat generation. We considered here only the stationary situation. The achieved numerical results are accurate and show that the applied homogenization technique works in practice. Finally the results of simulations for the two cases, the original model of the slot and the homogenized model chosen for the slot (unit cell), are compared to experimental results.

Alebouyeh Samami, Behzad; Pieper, Martin; Breitbach, Gerd; Hodapp, Josef

2014-12-01

171

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

172

Preparation of emulsions by rotor-stator homogenizer and ultrasonic cavitation for the cosmeceutical industry.  

PubMed

Oil-in-water (O/W) nanoemulsions play an important key role in transporting bioactive compounds into a range of cosmeceutical products to the skin. Small droplet sizes have an inherent stability against creaming, sedimentation, flocculation, and coalescence. O/W emulsions varying in manufacturing process were prepared. The preparation and characterization of O/W nanoemulsions with average diameters of as low as 62.99 nm from palm oil esters were carried out. This was achieved using rotor-stator homogenizer and ultrasonic cavitation. Ultrasonic cell was utilized for the emulsification of palm oil esters and water in the presence of mixed surfactants, Tween 80 and Span 80 emulsions with a mean droplet size of 62.99 nm and zeta potential value at -37.8 mV. Results were comparable with emulsions prepared with rotor-stator homogenizer operated at 6000 rpm for 5 min. The stability of the emulsions was evaluated through rheology measurement properties. This included non-Newtonian viscosity, elastic modulus G', and loss modulus G?. A highly stable emulsion was prepared using ultrasonic cavitation comprising a very small particle size with higher zeta potential value and G' > G? demonstrating gel-like behavior. PMID:23089355

Han, Ng Sook; Basri, Mahiran; Abd Rahman, Mohd Basyaruddin; Abd Rahman, Raja Noor Zaliha Raja; Salleh, Abu Bakar; Ismail, Zahariah

2012-01-01

173

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

174

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

175

Coupling of Low Speed Fan Stator Vane Unsteady Pressures to Duct Modes: Measured versus Predicted  

NASA Technical Reports Server (NTRS)

Uniform-flow annular-duct Green's functions are the essential elements of the classical acoustic analogy approach to the problem of computing the noise generated by rotor-stator interaction inside the fan duct. This paper investigates the accuracy of this class of Green's functions for predicting the duct noise levels when measured stator vane unsteady surface pressures are used as input to the theoretical formulation. The accuracy of the method is evaluated by comparing the predicted and measured acoustic power levels for the NASA 48 inch low speed Active Noise Control Fan. The unsteady surface pressures are measured,by an array of microphones imbedded in the suction and pressure sides of a single vane, while the duct mode levels are measured using a rotating rake system installed in the inlet and exhaust sections of the fan duct. The predicted levels are computed using properly weighted integrals of measured surface pressure distribution. The data-theory comparisons are generally quite good particularly when the mode cut-off criterion is carefully interpreted. This suggests that, at least for low speed fans, the uniform-flow annular-duct Green's function theory can be reliably used for prediction of duct mode levels if the cascade surface pressure distribution is accurately known.

Sutliff, Daniel L.; Heidelberg, Laurence J.; Envia, Edmane

1999-01-01

176

Turbulence characteristics of the Bödewadt layer in a large enclosed rotor-stator system  

NASA Astrophysics Data System (ADS)

A three-dimensional (3D) direct numerical simulation is combined with a laboratory study to describe the turbulent flow in an enclosed annular rotor-stator cavity characterized by a large aspect ratio G =(b-a)/h=18.32 and a small radius ratio a /b=0.152, where a and b are the inner and outer radii of the rotating disk and h is the interdisk spacing. The rotation rate ? under consideration is equivalent to the rotational Reynolds number Re =?b2/?=9.5×104, where ? is the kinematic viscosity of the fluid. This corresponds to a value at which an experiment carried out at the laboratory has shown that the stator boundary layer is turbulent, whereas the rotor boundary layer is still laminar. Comparisons of the 3D computed solution with velocity measurements have given good agreement for the mean and turbulent fields. The results enhance evidence of weak turbulence at this Reynolds number, by comparing the turbulence properties with available data in the literature [M. Lygren and H. I. Andersson, J. Fluid Mech. 426, 297 (2001)]. An approximately self-similar boundary layer behavior is observed along the stator side. The reduction of the structural parameter a1 under the typical value 0.15 and the variation in the wall-normal direction of the different characteristic angles show that this boundary layer is three-dimensional. A quadrant analysis [H. S. Kang, H. Choi, and J. Y. Yoo, Phys. Fluids 10, 2315 (1998)] of conditionally averaged velocities is performed to identify the contributions of different events (ejections and sweeps) on the Reynolds shear stress producing vortical structures. The asymmetries observed in the conditionally averaged quadrant analysis are dominated by Reynolds stress-producing events in this Bödewadt layer. Moreover, case 1 vortices (with a positive wall induced velocity) are found to be the major source of generation of special strong events, in agreement with the conclusions of Lygren and Andersson [J. Fluid Mech. 426, 297 (2001)].

Randriamampianina, Anthony; Poncet, Sébastien

2006-05-01

177

A numerical modelling of stator rotor interaction in a turbine stage with oscillating blades  

NASA Astrophysics Data System (ADS)

In real flows unsteady phenomena connected with the circumferential non-uniformity of the main flow and those caused by oscillations of blades are observed only jointly. An understanding of the physics of the mutual interaction between gas flow and oscillating blades and the development of predictive capabilities are essential for improved overall efficiency, durability and reliability. In the study presented, the algorithm proposed involves the coupled solution of 3D unsteady flow through a turbine stage and the dynamics problem for rotor-blade motion by the action of aerodynamic forces, without separating the outer and inner flow fluctuations. The partially integrated method involves the solution of the fluid and structural equations separately, but information is exchanged at each time step, so that solution from one domain is used as a boundary condition for the other domain. 3-D transonic gas flow through the stator and rotor blades in relative motion with periodicity on the whole annulus is described by the unsteady Euler conservation equations, which are integrated using the explicit monotonous finite volume difference scheme of Godunov Kolgan. The structural analysis uses the modal approach and a 3-D finite element model of a blade. The blade motion is assumed to be constituted as a linear combination of the first natural modes of blade oscillations, with the modal coefficients depending on time. A calculation has been done for the last stage of the steam turbine, under design and off-design regimes. The numerical results for unsteady aerodynamic forces due to stator rotor interaction are compared with results obtained while taking into account blade oscillations. The mutual influence of both outer flow non-uniformity and blade oscillations has been investigated. It is shown that the amplitude-frequency spectrum of blade oscillations contains the high-frequency harmonics, corresponding to the rotor moving past one stator blade pitch, and low-frequency harmonics caused by blade oscillations and flow non-uniformity downstream from the blade row; moreover, the spectrum involves the harmonics which are not multiples of the rotation frequency.

Gnesin, V. I.; Kolodyazhnaya, L. V.; Rzadkowski, R.

2004-11-01

178

Fault detection of eccentricity and bearing damage in a PMSM by means of wavelet transforms decomposition of the stator current  

Microsoft Academic Search

This paper presents the study of permanent magnet synchronous machines (PMSM) running with eccentricity and bearings damage. The objective is to detect and identify the fault through the current signature analysis. The stator current has been analyzed by means of both Fourier (FFT) and Discrete Wavelet (DWT) transforms. Simulations have been carried out with a two-dimensional (2-D) finite element analysis

J. Rosero; J. L. Romeral; J. Cusido; J. A. Ortega; A. Garcia

2008-01-01

179

Acoustic Scattering by Three-Dimensional Stators and Rotors Using the SOURCE3D Code. Volume 2; Scattering Plots  

NASA Technical Reports Server (NTRS)

This second volume of Acoustic Scattering by Three-Dimensional Stators and Rotors Using the SOURCE3D Code provides the scattering plots referenced by Volume 1. There are 648 plots. Half are for the 8750 rpm "high speed" operating condition and the other half are for the 7031 rpm "mid speed" operating condition.

Meyer, Harold D.

1999-01-01

180

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

E-print Network

ultrasonic motor V. Bolborici a, , F.P. Dawson b , M.C. Pugh c a University of Texas at El Paso, Department Keywords: Piezoelectric Ultrasonic Motor Stator Eigenfrequency a b s t r a c t Piezoelectric traveling wave rotary ultrasonic motors are motors that generate torque by using the fric- tion force between

Pugh, Mary

181

A stator-flux-based vector control method for parallel-connected multiple induction motors fed by a single inverter  

Microsoft Academic Search

This paper presents a novel vector control method for a parallel-connected multiple motor drive system. The proposed control method is based on the stator-flux, and is capable of accurate and responsive torque control even if there are the rotor velocity differences among the motors. To confirm the validity of the proposed control method, the authors compare a simulation result of

Y. Matsumoto; C. Osawa; T. Mizukami; S. Ozaki

1998-01-01

182

A threaded wobble motor with a 6-pole stator-a micro motor generating large linear displacement  

Microsoft Academic Search

This paper deals with the driving principle and the experimental demonstration of a micro motor which can convert rotation into linear motion and generate large displacement. The motor is a wobble type one; its rotor and stators have screw threads. When the rotor turns, it moves linearly in the axial direction like a screw. The range of linear motion is

Tetsuhiko Iizuka; Hiroyuki Fujita

1996-01-01

183

Magnetic analysis and comparison of Switched Reluctance Motors with different stator pole shapes using a 3D finite element method  

Microsoft Academic Search

Optimum design of switched reluctance motor (SRM) and it control circuits require a knowledge of its parameters, Such as inductance, flux linkage and Torque. In this paper, a model of SRM has been developed and analysed with ANSYS Workbench. The variation of Inductance, flux density and directional force with respect to rotor position for two different stator pole shapes has

M. Sundaram; P. Navaneethan; M. Vasanthakumar

2009-01-01

184

Experimental verification and analytical approach to influence stator skew on electromagnetic performance of permanent magnet generators with multipole rotor  

Microsoft Academic Search

This paper deals with experimental verification and analytical approach to influence stator skew on electromagnetic performance of a permanent magnet generator (PMG) with multipole rotor. The analytical expressions for magnetic field distributions are due to permanent magnets and the two-dimensional permeance function considering skew effects are established. On the basis of these analytical solutions, the analytical solutions for cogging torque

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

2009-01-01

185

Predictive Stator flux control with overmodulation and dynamic torque control at constant switching frequency in AC drives  

Microsoft Academic Search

In this paper, the authors propose a simple inverter switching strategy that achieves dynamic torque and dead-beat control of stator flux. Depending upon the error in torque, the torque controller creates a dynamic slip that defines a new flux reference. Error in flux is used to directly obtain the inverter switching states. The procedure to obtain the inverter duty cycle

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

2002-01-01

186

A distributed five-hole probe rake on stator blades for rotor exit measurement of a compressor  

Microsoft Academic Search

Each tube of five-holes probe will be placed at the same radius on five different stator blades. The diameter of the probe and the wall proximity effect are decreased. The distributed five-hole probe rake has been verified experimentally. Its dynamical frequency response is enhanced seven times and its characteristics are improved. The parameter measurement of each rotor exit in a

Qixun Lin; Chunying Shi; Gengsen Pan

1991-01-01

187

Core compressor exit stage study. Volume 5: Design and performance report for the Rotor C/Stator B configuration  

NASA Technical Reports Server (NTRS)

Rear stage blading designs that have lower losses in their endwall boundary layer regions were developed. The design of rotor-C and the performance results for rotor-C running with stator B are described. A low speed research compressor is utilized as the principal investigative tool. Four identical stages of blading are used to obtained data in a true multistage environment.

Wisler, D. C.

1981-01-01

188

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

189

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

190

Transient technique for measuring heat transfer coefficients on stator airfoils in a jet engine environment  

NASA Technical Reports Server (NTRS)

A transient technique was used to measure heat transfer coefficients on stator airfoils in a high-temperature annular cascade at real engine conditions. The transient response of thin film thermocouples on the airfoil surface to step changes in the gas stream temperature was used to determine these coefficients. In addition, gardon gages and paired thermocouples were also utilized to measure heat flux on the airfoil pressure surface at steady state conditions. The tests were conducted at exit gas stream Reynolds numbers of one-half to 1.9 million based on true chord. The results from the transient technique show good comparison with the steady-state results in both trend and magnitude. In addition, comparison is made with the STAN5 boundary layer code and shows good comparison with the trends. However, the magnitude of the experimental data is consistently higher than the analysis.

Gladden, H. J.; Proctor, M. P.

1985-01-01

191

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

192

Fault diagnosis of motor drives using stator current signal analysis based on dynamic time warping  

NASA Astrophysics Data System (ADS)

Electrical motor stator current signals have been widely used to monitor the condition of induction machines and their downstream mechanical equipment. The key technique used for current signal analysis is based on Fourier transform (FT) to extract weak fault sideband components from signals predominated with supply frequency component and its higher order harmonics. However, the FT based method has limitations such as spectral leakage and aliasing, leading to significant errors in estimating the sideband components. Therefore, this paper presents the use of dynamic time warping (DTW) to process the motor current signals for detecting and quantifying common faults in a downstream two-stage reciprocating compressor. DTW is a time domain based method and its algorithm is simple and easy to be embedded into real-time devices. In this study DTW is used to suppress the supply frequency component and highlight the sideband components based on the introduction of a reference signal which has the same frequency component as that of the supply power. Moreover, a sliding window is designed to process the raw signal using DTW frame by frame for effective calculation. Based on the proposed method, the stator current signals measured from the compressor induced with different common faults and under different loads are analysed for fault diagnosis. Results show that DTW based on residual signal analysis through the introduction of a reference signal allows the supply components to be suppressed well so that the fault related sideband components are highlighted for obtaining accurate fault detection and diagnosis results. In particular, the root mean square (RMS) values of the residual signal can indicate the differences between the healthy case and different faults under varying discharge pressures. It provides an effective and easy approach to the analysis of motor current signals for better fault diagnosis of the downstream mechanical equipment of motor drives in the time domain in comparison with conventional FT based methods.

Zhen, D.; Wang, T.; Gu, F.; Ball, A. D.

2013-01-01

193

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

194

Research on transient behaviors and detection methods of stator winding inter-turn short circuit fault in induction motors based on multi-loop mathematical model  

Microsoft Academic Search

This paper aims to the detection of stator winding inter-turn short circuit fault (SWITSCF) in induction motors. Firstly, the multi-loop mathematical models of squirrel cage induction motor, YN, Y or D connected, under the conditions that the motor is healthy\\/faulty with stator winding inter-turn shorts, are developed. Secondly, the transient simulation of SWITSCF as well as the related experiment is

Li Heming; Sun Liling; Xu Boqiang

2005-01-01

195

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

196

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

NASA Astrophysics Data System (ADS)

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

Lahriri, Said; Santos, Ilmar F.

2013-11-01

197

Analysis of efficiency characteristics of a single-stage turbine with downstream stators in terms of work and speed requirements  

NASA Technical Reports Server (NTRS)

One-dimensional mean-section flow and blade specific losses proportional to average specific kinetic energy are assumed in the analysis. Range of the work-speed parameter lambda considered includes low to moderate blade speeds with high specific work outputs, where critical turbojet, turbopump, and accessory-drive turbines are encountered. A diffusion factor of 0.5 limits the loading on the downstream stators. Turbine efficiences considered are total or aerodynamic, rating, and static. Efficiences of velocity-diagram types at impulse and that corresponding to values of maximum efficiency are presented and compared to indicate in what range of lambda downstream stators are beneficial as well as the attending improvements in efficiency.

Wintucky, William T; Stewart, Warner L

1957-01-01

198

Analysis of turbine stator adjustment required for compressor design-point operation in high Mach number supersonic turbojet engines  

NASA Technical Reports Server (NTRS)

For turbojet engines designed for flight Mach numbers of 2.5 and 3.0, use of turbine stator adjustment to maintain compressor design-point operation was evaluated analytically to determine the effect on the aerodynamics of the turbine. Since the effect of turbine stator adjustment is to make the turbine design sensitive to the particular engine design conditions selected, in some cases the turbine must be conservatively designed for the high-speed flight condition to assure satisfactory turbine performance at take-off. A new concept, the break-even point, is introduced to provide quick evaluation of the proximity of turbines to the blade-loading limit at any off-design operation.

English, Robert E; Cavicchi, Richard H

1953-01-01

199

A sensorless vector control system for induction motors using q-axis flux with stator resistance identification  

Microsoft Academic Search

This paper presents a sensorless vector control system for general-purpose induction motors, which is based on the observer theory and the adaptive control theories. The proposed system includes a rotor speed estimator using a q-axis flux and stator resistance identifier using the d-axis flux. The advantages of the proposed system are simplicity and avoidance of problems caused by using only

Mineo Tsuji; Shuo Chen; Katsuhiro Izumi; Eiji Yamada

2001-01-01

200

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

Microsoft Academic Search

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

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

1996-01-01

201

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

202

A Finite-Element Model of the Cyclic Aerodynamic Loading of a Turbine Rotor Due to an Upstream Stator  

Microsoft Academic Search

A finite-element model has been developed to predict the unsteady flow field in an axial turbine rotor cascade as a result of the wakes shed from an upstream stator blade row. The numerical model is based on a three-dimensional, time dependent, fully elliptic, finite element formulation of the Navier-Stokes equations cast in cylindrical coordinates. The relative motion between the blade

J. D. MACGREGOR; E. A. BASKHARONE

1996-01-01

203

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

NASA Astrophysics Data System (ADS)

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

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

204

Feasibility of Using PZT Actuators to Study the Dynamic Behavior of a Rotating Disk due to Rotor-Stator Interaction  

PubMed Central

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

205

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

206

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

207

Mixed eccentricity diagnosis in Inverter-Fed Induction Motors via the Adaptive Slope Transform of transient stator currents  

NASA Astrophysics Data System (ADS)

This paper researches the detection of mixed eccentricity in Inverter-Fed Induction Motors. The classic FFT method cannot be applied when the stator current captured is not in steady state, which is very common in these motors. Therefore, a transform able to detect the time-frequency evolutions of the components present in the transient signal captured must be applied. In order to optimize the result, a method to calculate the theoretical time-frequency evolution of the stator current components is presented, using only the captured current. This previously obtained information enables the use of the proposed transform: the Adaptive Slope Transform, based on appropriately choosing the atom slope in each point analyzed. Thanks to its adaptive characteristics, the time-frequency evolution of the main components in a stator transient current is traced precisely and with high detail in the 2D time-frequency plot obtained. As a consequence, the time-frequency plane characteristic patterns produced by the Eccentricity Related Harmonics are easily and clearly identified enabling a reliable diagnosis. Moreover, the problem of quantifying the presence of the fault is solved presenting a simple and easy to apply method. The transform capabilities have been shown successfully diagnosing an Inverter-Fed Induction Motor with mixed eccentricity during a startup, a decrease in the assigned frequency, and a load variation with and without slip compensation.

Pons-Llinares, J.; Antonino-Daviu, J.; Roger-Folch, J.; Moríñigo-Sotelo, D.; Duque-Pérez, O.

2014-10-01

208

Study of a Flow Control System in a High Turning Stator Cascade Using Dpiv  

NASA Astrophysics Data System (ADS)

A flow control system for a high turning stator cascade was investigated using Particle Image Velocimetry (PIV) and conventional pressure instrumentation. The system consists of small blowing cavities and suction holes in the blades. Experiments were performed in the transonic blowdown wind tunnel of Virginia Tech for various Mach numbers, cascade angles, and blowing and suction ratios. The results show that flow control can provide significant reduction in wake width and increase in turning. A 50coefficient was realized even though the blowing velocity was below design expectations. Through redesign of the flow control geometry, it is anticipated that even greater improvements regarding loss and turning can be achieved. Comparison with CFD results is also presented. The PIV system consists of two Nd:YAG lasers, a cross-correlation ES1 camera, an optical probe for laser-sheet delivery, plexiglass walls for optical access, and a seeding system. The optical probe can slide and rotate inside a glass tube mounted across the test section downstream the cascade. This allows the laser sheet to illuminate any location of the cascade in the main flow direction. Free-stream and blowing seed consisted of aluminum dioxide particles.

Estevadeordal, Jordi; Copenhaver, William; Ng, Wing; Carter, Casey

2001-11-01

209

Periodic transition on an axial compressor stator: Incidence and clocking effects. Part 2: Transition onset predictions  

SciTech Connect

Transition onset observations from a 1.5-stage axial compressor outlet stator presented in Part 1 of this paper are compared with the predictions of conventional transition correlations applied in a quasi-steady manner. The viscous/inviscid interaction code MISES is used to predict the blade surface pressure distributions, and boundary layer development. The temporal variation in transition onset is then predicted using ensemble-averaged free-stream turbulence data from the compressor measurements. This simple procedure captures most significant features of the complex transition process on the compressor, and is clearly superior to fixed transition models based on long-term average free-stream turbulence levels. Parallel computations for both natural and bypass transition modes indicate that the natural transition mode tends to dominate on the compressor. This is at variance with turbine airfoil experience, where bypass transition is clearly more important. Comparison of prediction and experiment highlights the significance of leading edge potential flow interactions in promoting periodic wake-induced transition. Viscous/inviscid interactions in the neighborhood of transition can also have an important influence on boundary layer stability and separation phenomena.

Solomon, W.J. [General Electric Aircraft Engines, Cincinnati, OH (United States); Walker, G.J.; Hughes, J.D. [Univ. of Tasmania, Hobart (Australia). School of Engineering

1999-07-01

210

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

NASA Astrophysics Data System (ADS)

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

Suzuki, Masaya; Inaba, Kazuaki; Yamamoto, Makoto

2008-06-01

211

Properties of Motility in Bacillus subtilis Powered by the H+- Coupled MotAB Flagellar Stator, Na+-Coupled MotPS or Hybrid Stators MotAS or MotPB  

PubMed Central

Bacillus subtilis has a single set of flagellar rotor proteins that interact with two distinct stator-force generators, the H+-coupled MotAB complex and the Na+-coupled MotPS complex, that energize rotation. Here, motility on soft agar plates and in liquid was assayed in wild-type B. subtilis and strains expressing only one stator, either MotAB, MotPS or hybrid MotAS or MotPB. The strains expressing MotAB or MotAS had an average of 11 flagella/cell while those expressing MotPS or MotPB had an average of 7 flagella/cell, while a Mot-less double mutant had 3-4 flagella/cell. MotAB had a more dominant role in motility than MotPS under most conditions, but MotPS supported comparable motility to MotAB on malate-containing soft agar plating media at elevated pH and Na+. MotAB supported much faster swimming speeds in liquid than MotPS, MotAS or MotPB under all conditions, but a contribution of MotPS to wild-type swimming was discernible from differences in swimming speeds of wild-type and MotAB at elevated viscosity, pH and Na+. Swimming supported by MotPS and MotAS was stimulated by Na+ and elevated pH whereas the converse was true of MotAB and MotPB. This suggests that MotAS is Na+-coupled and MotPB is H+-coupled and that MotB and MotS are major determinants of ion-coupling. However, the swimming speed supported by MotPB, as well as MotPS and MotAS, was inhibited severely at Na+ concentrations above 300 mM whereas MotAB-dependent swimming was not. The presence of either the MotP or MotS component in the stator also conferred sensitivity to inhibition by an amiloride analogue. These observations suggest that MotP contributes to Na+-coupling and inhibition by Na+ channel inhibitors. Similarly, a role for MotA in H+-dependent stator properties is indicated by the larger effects of pH on the Na+-response of MotAS vs MotPS. Finally, optimal function at elevated viscosity was found only in MotPS and MotPB and is therefore conferred by MotP. PMID:16095621

Ito, Masahiro; Terahara, Naoya; Fujinami, Shun; Krulwich, Terry Ann

2008-01-01

212

Velocity surveys in a turbine stator annular-cascade facility using laser Doppler techniques. [flow measurement and flow characteristics  

NASA Technical Reports Server (NTRS)

A laser Doppler velocimeter (LDV) was used to determine the flow conditions downstream of an annular cascade of stator blades operating at an exit critical velocity ratio of 0.87. Two modes of LDV operation (continuous scan and discrete point) were investigated. Conventional pressure probe measurements were also made for comparison with the LDV results. Biasing errors that occur in the LDV measurement of velocity components were also studied. In addition, the effect of pressure probe blockage on the flow conditions was determined with the LDV. Photographs and descriptions of the test equipment used are given.

Goldman, L. J.; Seasholtz, R. G.; Mclallin, K. L.

1976-01-01

213

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

214

Analysis and testing for rotordynamic coefficients of turbulent annular seals with different, directionally-homogeneous surface-roughness treatment for rotor and stator elements  

NASA Technical Reports Server (NTRS)

A combined analytical-computational method has been developed to calculate the transient pressure field and rotordynamic coefficients for high-pressure annular seals. The solution procedure applies to constant-clearance or the convergent tapered geometries of multistage centrifugal pumps which may have different surface roughness conditions on the stator and rotor seal elements. In experimental calculations with the method, the turbulent equations of Hirs (1973) are modified slightly to account for different surface roughness conditions, and a perturbation analysis is employed to develop zeroth and first order perturbation equations. Zeroth equations are also used to define both the leakage and circumferential flow due to shear stresses around the stator and rotor surfaces. The solution to analytical equations for four different surface roughnesses confirm the predicted net damping for the seals. A round-holed stator pattern yielded the highest net damping and lowest leakage of all the seals tested.

Childs, D. W.; Kim, C.-H.

1984-01-01

215

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

216

Impact of clocking on the aero-thermodynamics of a second stator tested in a one and a half stage HP turbine  

NASA Astrophysics Data System (ADS)

This paper focuses on the experimental investigation of the time-averaged and time-accurate aero-thermodynamics of a second stator tested in a 1.5 stage high-pressure turbine. The effect of clocking on aerodynamic and heat transfer are investigated. Tests are performed under engine representative conditions in the VKI compression tube CT3. The test program includes four different clocking positions, i.e. relative pitch-wise positions between the first and the second stator. Probes located upstream and downstream of the second stator provide the thermodynamic conditions of the flow field. On the second stator airfoil, measurements are taken around the blade profile at 15, 50 and 85% span with pressure sensors and thin-film gauges. Both time-averaged and time-resolved aspects of the flow field are addressed. Regarding the time-averaged results, clocking effects are mainly observed within the leading edge region of the second stator, the largest effects being observed at 15% span. The surface static pressure distribution is changed locally, hence affecting the overall airfoil performance. For one clocking position, the thermal load of the airfoil is noticeably reduced. Pressure fluctuations are attributed to the passage of the upstream transonic rotor and its associated pressure gradients. The pattern of these fluctuations changes noticeably as a function of clocking. The time-resolved variations of heat flux and static pressure are analyzed together showing that the major effect is due to a potential interaction. The time-resolved pressure distribution integrated along the second stator surface yields the unsteady forces on the vane. The magnitude of the unsteady force is very dependent on the clocking position.

Billiard, N.; Paniagua, Guillermo; Dénos, R.

2008-06-01

217

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

218

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

219

A 3D finite-element computation of eddy currents and losses in the stator end laminations of large synchronous machines  

SciTech Connect

Eddy current losses due to axial fluxes are computed in the stator end laminations of a salient-pole synchronous machine at open-circuit operating condition. The calculation is carried out with the aid of a 3D finite-element package which uses a linear T-{phi} formulation. The domain spans a full pole pitch of the machine. The flux densities computed in the end region at points outside the stator core are compared with experimental measurements. The results and the limitations of the model are discussed.

Silva, V.C. [Univ. de Sao Paulo (Brazil)] [Univ. de Sao Paulo (Brazil); Meunier, G.; Foggia, A. [Domaine Univ., Saint Martin d`Heres (France). Lab. d`Electrotechnique de Grenoble] [Domaine Univ., Saint Martin d`Heres (France). Lab. d`Electrotechnique de Grenoble

1996-05-01

220

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

221

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

222

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

223

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

224

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

SciTech Connect

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

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

1997-04-01

225

Dual rotor single- stator axial air gap PMSM motor/generator drive for high torque vehicles applications  

NASA Astrophysics Data System (ADS)

The actual e - continuously variable transmission (e-CVT) solution for the parallel Hybrid Electric Vehicle (HEV) requires two electric machines, two inverters, and a planetary gear. A distinct electric generator and a propulsion electric motor, both with full power converters, are typical for a series HEV. In an effort to simplify the planetary-geared e-CVT for the parallel HEV or the series HEV we hereby propose to replace the basically two electric machines and their two power converters by a single, axial-air-gap, electric machine central stator, fed from a single PWM converter with dual frequency voltage output and two independent PM rotors, destined for hybrid electric vehicles (HEV) and military vehicles applications. The proposed topologies and the magneto-motive force analysis are the core of the paper.

Tutelea, L. N.; Deaconu, S. I.; Boldea, I.; Popa, G. N.

2014-03-01

226

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

227

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

228

Cold-air performance of a 15. 41-cm-tip-diameter axial-flow power turbine with variable-area stator designed for a 75kW automotive gas-turbine engine  

Microsoft Academic Search

Experimentally determined performance data are presented for the power turbine stage of the Department of Energy upgraded automotive gas turbine engine. The power turbine is a single-stage, axial-flow design with pivotable vanes to vary stator area for engine control and braking. The stage performance evaluation was performed with dry air at nominal stator inlet conditions of 320°K and 0.409 atmosphere.

K. L. McLallin; M. G. Kofskey; R. Y. Wong

1982-01-01

229

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

230

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

NASA Technical Reports Server (NTRS)

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, Reynolds number, and relative circumferential position of the first and second stators. Aerodynamic measurements include distributions of the mean and fluctuating velocities at the turbine inlet and, for each airfoil row, midspan airfoil surface pressures and circumferential distributions of the downstream steady state pressures and fluctuating velocities. Analytical results include airfoil heat transfer predictions and a examination of solutions of the unstead boundary layer equipment.

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

1987-01-01

231

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

232

ROTOR-STATOR INTERACTION IN A HIGHLY-LOADED, SINGLE-STAGE, LOW-SPEED AXIAL COMPRESSOR:UNSTEADY MEASUREMENTS IN THE ROTOR RELATIVE FRAME  

Microsoft Academic Search

Unsteady measurements were performed on rotor and stator blades of a highlyloaded 1.5-stage, low-speed axial compressor cascade using dynamic skin-friction measurement techniques. The project focusses on advanced 3D compressor blade design and has the potential to improve tip-clearance flow control at high loading by introducing different advanced unsteady measurement techniques. As an alternative to typical hot films, a novel surface

O. Burkhardt; W. Nitsche; M. Goller; M. Swoboda; V. Guemmer; H. Rohkamm; G. Kosyna

233

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

234

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

235

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

236

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

237

Single-stage experimental evaluation of tandem-airfoil rotor and stator blading for compressors. Part 2: Data and performance for stage A  

NASA Technical Reports Server (NTRS)

Stage A, comprised of a conventional rotor and stator, was designed and tested to establish a performance baseline for comparison with the results of subsequent tests planned for two tandem-blade stages. 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 A achieved a maximum adiabatic efficiency of 85.1 percent at a pressure ratio of 1.29. The stage maximum adiabatic efficiency was 78.6 percent at a pressure ratio of 1.27.

Brent, J. A.

1972-01-01

238

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

239

Single-stage evaluation of highly-loaded high-Mach-number compressor stages 5. Data and performance of baseline, corner-blow wall suction and combined corner blow wall suction stator  

NASA Technical Reports Server (NTRS)

A single-stage compressor with a rotor tip speed of 1600 ft/sec and a 0.5 hub tip ratio was used to investigate the effects of several stator endwall treatment methods on stage range and performance. These endwall treatment methods consisted of stator corner-blow, annular wall suction upstream of stator leading edge, and combined corner-blow and annular wall suction. The overall stage performance with corner blow was essentially the same as the baseline performance. The performance for the annular wall suction and the combined corner-blow and wall suction showed a reduction in peak efficiency of 2.5 percentage points compared to the baseline data.

Nikkanen, J. P.; Brooky, J. P.

1972-01-01

240

Component Performance Investigation of J71 Experimental Turbine. Part 2; Internal-Flow Conditions with 97-Percent-Design Stator Areas  

NASA Technical Reports Server (NTRS)

An experimental investigation of the internal-flow conditions of a J71 experimental turbine equipped with 97-percent-design stator areas was conducted at equivalent design speed and near equivalent design work. The results of the investigation indicate that the stage work distribution closely approximates design, the actual distribution being 44.1, 33.4, and 22.5 percent for the first, second, and third stages, respectively. The first-, second-, and third-stage efficiencies were 0.894, 0.858, and 0.792, respectively. The first and second stages exhibited loss regions near the hub and tip at the rotor blade outlets. The hub loss region is attributed to stator secondary flows, and a contributing factor to the tip loss region may be the high design diffusion on the rotor blade suction surface near the tip. The loss in the third stage is appreciably greater than that in the first or second stage. The fact that the third rotor is unshrouded and has a nominal tip clearance of 0.120 inch may contribute to the higher loss in the tip region of the third stage.

Rebeske, John J., Jr.; Petrash, Donald A.

1956-01-01

241

Cold air study of the effect on turbine stator blade aerodynamic performance of coolant ejection from various trailing edge slot geometries. 2: Comparison of experimental and analytical results  

NASA Technical Reports Server (NTRS)

Experimentally determined efficiencies of turbine stator blades having trailing-edge coolant ejection are compared with efficiencies predicted from two previously published approximate analytical methods. The experimental results were obtained from two-dimensional data with the temperature of the primary and coolant flows both being nearly ambient. Data from five stator blade configurations having different slotted trailing-edge geometries were included in the comparison. The two analytical methods gave results which agreed reasonably well with experimental results. An average of the absolute values of differences between experimental and predicted efficiencies for all five blade configurations showed that one method gave average efficiency differences which were about 1.3 percent different than experimental efficiencies, while the other method gave average efficiency differences that were about 0.7 percent different than experimental. However, in some instances, maximum differences of as much as 4 percent occurred. A comparison between experimental and analytical results indicated that the ratio of trailing-edge slot width to trailing-edge thickness influences the measured efficiencies to a greater extent than is accounted for by either analytical model.

Prust, H. W., Jr.

1975-01-01

242

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

243

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

244

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.

245

New solutions in the maintenance of the asynchronous motors with integrated gear and single demountable bearing shield: Devices to extract and insert the ferromagnetic cores of the stator (case study)  

Microsoft Academic Search

Generally, asynchronous motors used in actuator systems (whether they are three-phase or single-phase motors) have two demountable bearing shields. This design allows easy access to the winding, on both sides of the stator, making the maintenance a relatively simple process. Another type of motor, with a special design, also exists. It has a single removable bearing shield, the other being

Daniel Necula; Nicolae Vasile; Mihail-Florin Stan

2011-01-01

246

Cold-air study of the effect on turbine stator blade aerodynamic performance of coolant ejection from various trailing-edge slot geometries. 1: Experimental results  

NASA Technical Reports Server (NTRS)

Trailing-edge slot configurations were investigated in a two-dimensional cascade of turbine stator blades. The trailing-edge slots were incorporated into blades with round trailing edges. The five blade configurations investigated included blades with two different trailing-edge thicknesses and four different slot widths. The results of the investigation showed that there was, in general, a significant increase in primary-air efficiency due to the coolant flow, the increase varying with slot configuration. For the five configurations tested, the average percent change in primary-air efficiency per percent coolant flow varied almost linearly from zero to about 1.4 percent over a range of coolant- to primary-air exit-velocity ratios between 0 and 1.2. However, for different configurations there was considerable deviation from the average values in the lower range of exit velocity ratios.

Prust, H. W., Jr.; Bartlett, W. M.

1974-01-01

247

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

248

Blade row dynamic digital compression program. Volume 2: J85 circumferential distortion redistribution model, effect of Stator characteristics, and stage characteristics sensitivity study  

NASA Technical Reports Server (NTRS)

The results of dynamic digital blade row compressor model studies of a J85-13 engine are reported. The initial portion of the study was concerned with the calculation of the circumferential redistribution effects in the blade-free volumes forward and aft of the compression component. Although blade-free redistribution effects were estimated, no significant improvement over the parallel-compressor type solution in the prediction of total-pressure inlet distortion stability limit was obtained for the J85-13 engine. Further analysis was directed to identifying the rotor dynamic response to spatial circumferential distortions. Inclusion of the rotor dynamic response led to a considerable gain in the ability of the model to match the test data. The impact of variable stator loss on the prediction of the stability limit was evaluated. An assessment of measurement error on the derivation of the stage characteristics and predicted stability limit of the compressor was also performed.

Tesch, W. A.; Steenken, W. G.

1978-01-01

249

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

250

Functional chimeras of flagellar stator proteins between E. coli MotB and Vibrio PomB at the periplasmic region in Vibrio or E. coli  

PubMed Central

The bacterial flagellar motor has a stator and a rotor. The stator is composed of two membrane proteins, MotA and MotB in Escherichia coli and PomA and PomB in Vibrio alginolyticus. The Vibrio motor has a unique structure, the T ring, which is composed of MotX and MotY. Based on the structural information of PomB and MotB, we constructed three chimeric proteins between PomB and MotB, named PotB91, PotB129, and PotB138, with various chimeric junctions. When those chimeric proteins were produced with PomA in a ?motAB strain of E. coli or in ?pomAB and ?pomAB ?motX strains of Vibrio, all chimeras were functional in E. coli or Vibrio, either with or without the T ring, although the motilities were very weak in E. coli. Furthermore, we could isolate some suppressors in E. coli and identified the mutation sites on PomA or the chimeric B subunit. The weak function of chimeric PotBs in E. coli is derived mainly from the defect in the rotational switching of the flagellar motor. In addition, comparing the motilities of chimera strains in ?pomAB, PotB138 had the highest motility. The difference between the origin of the ?1 and ?2 helices, E. coli MotB or Vibro PomB, seems to be important for motility in E. coli and especially in Vibrio. PMID:25630862

Nishino, Yuuki; Onoue, Yasuhiro; Kojima, Seiji; Homma, Michio

2015-01-01

251

Como Lo Hago Yo: Tratamiento Quirurgico Del Mielomeningocele  

PubMed Central

En Argentina hay plan de fortificación con ácido fólico. Diagnostico prenatal no siempre es correcto. Cierre según técnica. Cerramos músculo. No favorecemos corpectomía temprana en casos de cifosis. Suturamos la plaqueta. Cerramos el plano muscular. Hidrocefalia: Válvula de derivación, generalmente dentro de los dos primeros meses. Ventriculostomía no está indicada. Chiari II. Laminectomia cervical alta. Siringomielia: Derivación desde la cavidad al peritoneo. PMID:24791219

Portillo, Santiago

2014-01-01

252

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

253

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

254

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.

255

Measurements of the unsteady flow field within the stator row of a transonic axial-flow fan. 1: Measurement and analysis technique  

NASA Technical Reports Server (NTRS)

This two-part paper presents laser anemometer measurements of the unsteady velocity field within the stator row of a transonic axial-flow fan. The objective is to provide additional insight into unsteady blade-row interactions within high speed compressors which affect stage efficiency, energy transfer, and other design considerations. Part 1 describes the measurement and analysis techniques used for resolving the unsteady flow field features. The ensemble-average and variance of the measured velocities are used to identify the rotor wake generated and unresolved unsteadiness, respectively. (Rotor wake generated unsteadiness refers to the unsteadiness generated by the rotor wake velocity deficit and the term unresolved unsteadiness refers to all remaining contributions to unsteadiness such as vortex shedding, turbulence, mass flow fluctuations, etc.). A procedure for calculating auto and cross correlations of the rotor wake generated and unresolved unsteady velocity fluctuations is described. These unsteady-velocity correlations have significance since they also result from a decomposition of the Navier-Stokes equations. This decomposition of the Navier-Stokes equations resulting in the velocity correlations used to describe the unsteady velocity field will also be outlined in this paper.

Suder, K. L.; Hathaway, M. D.; Okiishi, T. H.; Strazisar, A. J.; Adamczyk, J. J.

1987-01-01

256

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.

257

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.

258

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

259

Omnipresencia del paralelismo Objetivos del proyecto  

E-print Network

-Secundaria Incorporaci´on de contenidos de programaci´on paralela en la rama de tecnolog´ias inform´aticas Facultad;Omnipresencia del paralelismo Objetivos del proyecto Material a desarrollar Programaci´on paralela Para explotar componentes computacionales, para lo que se utiliza la programaci´on paralela. Tipos b´asicos: Dentro de un

Giménez, Domingo

260

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.

261

Redes sociales del NCI  

Cancer.gov

Instituto Nacional del CáncerLa página de Facebook cuenta con información de cáncer dirigida al público de habla hispana. Visite nuestra página para leer noticias sobre la investigación del cáncer, conocer los recursos del NCI y publicar sus comentarios y preguntas relacionadas con el cáncer.

262

INTRODUCCION DESCRIPCION DEL PROGRAMA  

E-print Network

INTRODUCCION DESCRIPCION DEL PROGRAMA ADMISION, BECAS E INSTRUMENTOS DE APOYO Programa de Doctorado´atica, U. de Concepci´on, Chile #12;INTRODUCCION DESCRIPCION DEL PROGRAMA ADMISION, BECAS E INSTRUMENTOS DE´on, Chile #12;INTRODUCCION DESCRIPCION DEL PROGRAMA ADMISION, BECAS E INSTRUMENTOS DE APOYO ENTORNO LA

Bürger, Raimund

263

The effects of inlet turbulence and rotor/stator interactions on the aerodynamics and heat transfer of a large-scale rotating turbine model. Volume 2: Heat transfer data tabulation. 15 percent axial spacing  

NASA Technical Reports Server (NTRS)

A combined experimental and analytical program was conducted to examine the effects of inlet turbulence on airfoil heat transfer. The experimental portion of the study was conducted in a large-scale (approx 5X engine), ambient temperature, rotating turbine model configured in both single stage and stage-and-a-half arrangements. Heat transfer measurements were obtained using low-conductivity airfoils with miniature thermcouples 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, first-stator/rotor axial spacing, Reynolds number and relative circumferential position of the first and second stators. Aerodynamic measurements obtained as part of the program include distributions of the mean and fluctuating velocities at the turbine inlet and, for each airfoil row, midspan airfoil surface pressures and circumferential distributions of the downstream steady state pressures and fluctuating velocities. Analytical results include airfoil heat transfer predictions produced using existing 2-D boundary layer computation schemes and an examination of solutions of the unsteady boundary layer equations. The results are reported in four separate volumes, of which this is Volume 2: Heat Transfer Data Tabulation; 15 Percent Axial Spacing.

Dring, R. P.; Blair, M. F.; Joslyn, H. D.

1986-01-01

264

The effects of inlet turbulence and rotor/stator interactions on the aerodynamics and heat transfer of a large-scale rotating turbine model. Part 4: Aerodynamic data tabulation  

NASA Technical Reports Server (NTRS)

A combined experimental and analytical program was conducted to examine the effects of inlet turbulence and airfoil heat transfer. The experimental portion of the study was conducted in a large-scale (approx. 5X engine), ambient temperature, rotating turbine model configured in both single-stage and stage-and-a-half arrangements. 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, first stator-rotor axial spacing, Reynolds number and relative circumferential position of the first and second stators. Aerodynamic measurements obtained include distributions of the mean and fluctuating velocities at the turbine inlet and, for each airfoil row, midspan airfoil surface pressures and circumferential distributions of the downstream steady state pressures and fluctuating velocities. Results include airfoil heat transfer predictions produced using existing 2-D boundary layer computation schemes and an examination of solutions of the unsteady boundary layer equations.

Dring, R. P.; Joslyn, H. D.; Blair, M. F.

1987-01-01

265

Acuerdo del Programa del Mal Comportamiento Nombre del Nio: _______________________ Fecha_____________________  

E-print Network

: _______________________ Fecha_____________________ Nombre del padre_______________________ Problemas de la conducta son niño es capaz a esta edad de aprender esta conducta? Sí____ No____ ¿Se portan los otros niños de la misma edad con la conducta deseada? Sí_____ No_____ Si el niño nunca se ha portado con la conducta

266

EVALUACIN DEL IMPACTO AMBIENTAL  

E-print Network

EVALUACIÓN DEL IMPACTO AMBIENTAL Grado en Ciencias Ambientales Universidad de Alcalá Curso DEL IMPACTO AMBIENTAL Código: 670020 Titulación en la que se imparte: Grado en Ciencias Ambientales que se imparte: Español 1. PRESENTACIÓN La evaluación de impacto ambiental de proyectos es un

Espigares, Tíscar

267

MEMORIA DEL DEPARTAMENTO  

E-print Network

ESCUELA UNIVERSITARIA Masó Pareja, Alfredo - 4 - #12;Memoria del Departamento de Fundamentos del Análisis. Mariscal Arlabán, Asier, doctor por la University of Chicago. Martínez Gorricho, Silvia, doctora por la Chicago. Turino, Francesco, doctor por la Universitat Pompeu Fabra. PROFESORES ASOCIADOS Ariza Jiménez

Escolano, Francisco

268

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.

269

Fisiopatología del estreñimiento  

Microsoft Academic Search

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

Peter J. Milla

2007-01-01

270

Il problema del litio.  

NASA Astrophysics Data System (ADS)

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

D'Antona, F.

1995-03-01

271

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).

272

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.

273

DIANA: Anlisis del discurso para la comprensin del conocimiento  

E-print Network

DIANA: Análisis del discurso para la comprensión del conocimiento DIANA: DIscourse ANAlysis by the Spanish Ministry of Economy and Competitiveness. Paolo Rosso coordinates the DIANA project and leads

Rosso, Paolo

274

Pruebas de Papanicolaou y del virus del papiloma humano (VPH)  

Cancer.gov

Hoja informativa que describe los exámenes selectivos de detección del cáncer de cérvix, los cuales incluyen la prueba de Papanicolaou y la prueba de los virus del papiloma humano. La hoja informativa incluye también información acerca de las pautas de exámenes de detección del cáncer de cérvix.

275

Publicacin en Internet de los Datos del Herbario del  

E-print Network

Publicación en Internet de los Datos del Herbario del Departamento de Biología del Recinto-MAPR · Upgrading and Internet publication of the Herbarium of the Department of Biology at the University of Puerto datos a través de la Internet. #12;Georeferenciación · Coordenadas e información obtenidas de la

Gilbes, Fernando

276

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.

277

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.

278

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.

279

Instantánea del cáncer de riñón  

Cancer.gov

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

280

Instantánea del cáncer de tiroides  

Cancer.gov

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

281

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.

282

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.

283

Instantánea del cáncer de ovario  

Cancer.gov

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

284

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.

285

Instantánea del cáncer de estómago  

Cancer.gov

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

286

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.

287

Grupos financieros al servicio del rey de Espaa Fines del siglo XVII -principios del XVIII  

E-print Network

Grupos financieros al servicio del rey de España Fines del siglo XVII - principios del XVIII Existe, en un primer momento, bajo el ángulo casi exclusivo de los servicios financieros al Estado2 . La financieros, arrendamientos de impuestos, derechos señoriales o ingresos privados, suministro de víveres, de

Paris-Sud XI, Université de

288

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

289

Temas y rumbos del teatro rural hispanoamericano del siglo XX.  

E-print Network

Argentina. Digno de encomio, pues, el esfuerzo de Buenaventura y Gene por continuar la tradición del teatro folklórico.3 En lo que atañe a las creencias y al temperamento del campesino criollo, los autores hispanoamericanos han dado en la escena un... hijo del patrón que abusó de la inocencia de su prometida. Sabe que el encuentro podría ser funesto. El hombre de campo es también supersticioso. A veces mezcla las creencias de orden supersticioso con las religiosas. La presencia de ciertas aves...

Neglia, Erminio G.

1971-10-01

290

Two-dimensional cold-air cascade study of a film-cooled turbine stator blade. 4: Comparison of experimental and analytical aerodynamic results for blade with 12 rows of 0.076-centimeter-(0.030-inch-) diameter holes having streamwise ejection angles  

NASA Technical Reports Server (NTRS)

Previously published experimental aerodynamic efficiency results for a film cooled turbine stator blade are compared with analytical results computed from two published analytical methods. One method was used as published; the other was modified for certain cases of coolant discharge from the blade suction surface. For coolant ejection from blade surface regions where the surface static pressures are higher than the blade exit pressure, both methods predict the experimental results quite well. However, for ejection from regions with surface static pressures lower than the blade exit pressure, both methods predict too small a change in efficiency. The modified method gives the better prediction.

Prust, H. W., Jr.

1978-01-01

291

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.

292

Competitividad del sector del vidrio templado en Colombia  

Microsoft Academic Search

La industria nacional del vidrio templado es un sector en crecimiento, que necesita desarrollar ventajas competitivas como la innovación en sus procesos y productos a través de tecnología dura y blanda, y desplegar una logística integrada que permita la articulación de la cadena de valor y la orientación al cliente. Las empresas del sector vienen desarrollando, de acuerdo con su

Javier Mauricio Mendoza Paredes

2008-01-01

293

Vacunas contra los virus del papiloma humano  

Cancer.gov

Hoja informativa acerca de las vacunas contra los virus del papiloma humano (VPH) para prevenir infecciones con ciertos tipos de VPH, los cuales son la causa principal del cáncer de cuello del útero o cérvix.

294

Ceramic turbine stator vane and shroud support  

DOEpatents

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

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

1981-01-01

295

Simulating Nonlinear Stator Noise for Active Control  

NASA Technical Reports Server (NTRS)

This paper outlines an idea to achieve this type of active control with on-blade actuators. First, a simple analytical example demonstrates how a simple actuator could be used to nonlinearly control sound. Second, results from a realistic geometry demonstrate high amplitude vortical gusts that produce nonlinear harmonics which can destructively interfere with otherwise unattenuating (propagating) acoustical modes. We focus on the 2BPF acoustic response here to simplify the presentation and to show that nonlinear cancellation is effective on realistic blade rows, but similar simulations for higher frequencies have also been successfully completed.

Dyson. R. W.; Hixon, R.; Nallasamy, R. M.; Sawyer, S.

2003-01-01

296

modelado y analisis del transporte del herbicida glifosato  

E-print Network

(2) Departamento de Ingeniería del Terreno, Universidad Politécnica de Cataluña (España). (3) Department of ... tools for the study of water and contaminant transport in the unsaturated zone. ..... Dynamics of Fluids in Porous Media. Esevier ...

2001-03-12

297

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”.

298

Antioxidantes y prevención del cáncer  

Cancer.gov

Hoja informativa acerca de los antioxidantes, sustancias que pueden proteger las células del daño causado por moléculas inestables conocidas como radicales libres. El daño de los radicales libres puede resultar en cáncer.

299

NOTICIAS DEL 24/Julio/08  

E-print Network

de la materia oculta del Universo "Estamos mirando a los cielos, y usando los instrumentos más instrumentos más grandes para ayudarnos a predecir qué sucederá con las cosas más pequeñas", dijo David Toback

Toback, David

300

Case Study: del Amo Bioventing  

EPA Science Inventory

The attached presentation discusses the fundamentals of bioventing in the vadose zone. The basics of bioventing are presented. The experience to date with the del Amo Superfund Site is presented as a case study....

301

Alberto del Pozo  

NSDL National Science Digital Library

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

302

PARAULES DEL RECTOR EN L'ACTE DE CELEBRACI DEL NADAL DEL 2008  

E-print Network

és el quart any que m'apropo a aquest faristol per desitjar-vos Bon Nadal i el millor per al proper aniversari de la Declaració Universal dels Drets Humans de les Nacions Unides. La declaració ­us en recomano, tot allò que causa la misèria dels humans: les guerres, la pobresa extrema, la crueltat. Uns versos de

Verschure, Paul

303

Inauguracin del "Frum del Mediterrneo" Alicante, 24 de marzo de 2004  

E-print Network

recordar a las víctimas del terror del 11 de marzo, a sus familiares y amigos, y en ellas a todas las nuestros malos sueños y presagios. Como negar que para muchos de nosotros, la percepción del islam por

Escolano, Francisco

304

Características del viento en estrellas Be derivadas del perfil H?  

NASA Astrophysics Data System (ADS)

El estudio teórico de perfiles H? y su variabilidad en estrellas Be ha sido frecuentemente desarrollado en base a modelos de envolturas circunestelares inhomogéneas, donde la geometría del material es responsable de la forma del perfil dependiendo de la dirección de observación. Nosotros damos una interpretación alternativa y proponemos que la mayoría de las propiedades de esta línea tienen origen en la base de un viento estelar y de una estructura cromosférica anexa a la fotósfera. Encontramos que típicos perfiles H? en Be, como son los llamados pole-on y winebottle, pueden ser reproducidos cualitativamente sin recurrir a la existencia de una envoltura asimétrica. Analizamos como la línea H? permite identificar la posible estructura del viento en la región donde éste se inicia.

Rohrmann, R.; Cidale, L.

305

El libro del Relogio del Palacio de las Horas  

NASA Astrophysics Data System (ADS)

This paper resume the investigation entitled ``El libro del Relogio del Palacio de las Horas''. That consist in an edition of the original text of the book of the Clock of the Palace of the Hours from the Books of the knowledge of Astronomy of Alfonso X (Manuscript 156, Complutense University). And a description of the astronomical functionality of the Clock of the Palace of the Hours. It includes a geometric description of the positional astronomy on which the operation of the Palace is based.

Morales, J. D.

2009-08-01

306

EL ROL DEL GNERO DENTRO DEL PROCESO DE APRENDIZAJE COLABORATIVO  

E-print Network

de sexo y la forma en que esto afecta las actividades colaborativas. En el presente trabajo se describen los resultados de un experimento desarrollado con el fin de establecer que la diferencia de sexo]. Varios estudios también han demostrado que las diferencias de sexo en el uso del computador están

Guerrero, Luis

307

El papel del estado en la construcción del desarrollo sostenible: el caso del turismo en el Caribe Insular  

Microsoft Academic Search

La discusión acerca de la pertinencia de la intervención estatal en el mercado ha sido reiterativa en la historia del pensamiento económico. El turismo es otro ejemplo de que la regulación es no sólo necesaria sino fundamental, para corregir las asimetrías de un mercado que está lejos de cumplir los supuestos que motivaron la teoría del interés individual y del

Johannie James Cruz

2009-01-01

308

Aggiornamento del Piano Forestale Regionale: obiettivi e  

E-print Network

31-01-2013 1 Aggiornamento del Piano Forestale Regionale: obiettivi e azioni da condividere Davide green economy 2. Settore forestale: una green economy o una grey economy? 3. La struttura del Piano 4

Pettenella, Davide

309

UNIVERSIDAD SIMON BOLIVAR SEDE DEL LITORAL  

E-print Network

UNIVERSIDAD SIMON BOLIVAR SEDE DEL LITORAL ESPECIALIZACIÓN EN TELECOMUNICACIONES DECANATO DE comportamiento de las empresas del sector de las Telecomunicaciones considerando aspectos tecnológicos, políticos comunicación. Las organizaciones y su entorno. 2.- Entorno económico de las telecomunicaciones. Nociones

Vásquez, Carlos

310

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.

311

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.

312

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}@eia.udg.es Resumen. En el presente artículo se describe la arquitectura de un sistema inte- gral de gestión del ancho 4 detalla la arquitectura propuesta del sistema. Por último, se presentan las conclusiones y futuros

Ortega, Eusebi Calle

313

Elementos estratégicos para afianzar y mejorar la competitividad del Valle del Cauca  

Microsoft Academic Search

El estudio de competitividad del departamento del Valle del Cauca aborda el análisis simultáneo de los factores competitivos que integran el desarrollo económico regional; desempeño de los sectores productivos, la inserción internacional del sector industrial, la infraestructura, el capital humano y social, el avance tecnológico, el medioambiente, y los recursos institucionales. El examen de los factores competitivos y su contraste

Manuel Guillermo Bonilla; Juan Carlos Ramírez J

2005-01-01

314

Las ganancias del comercio y el intercambio desigual en los modelos del comercio internacional  

Microsoft Academic Search

Se examina el problema del intercambio desigual de trabajo entre países desarrollados y en desarrollo y su vinculación con las condiciones del comercio de beneficio mutuo. Para ello se utilizan los principales modelos teóricos del comercio internacional basado en las ventajas comparativas, y se amplía al caso de dos factores el concepto de relación de intercambio de trabajo derivada del

Francisco Martínez Soler; Andrei Martínez Finkelshtein

2005-01-01

315

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

316

La teoría General del Empleo  

Microsoft Academic Search

I. Comentarios sobre las cuatro discusiones en la edición anterior de puntos de la Teoría General, 209. - II. Ciertos puntos definitivos en los que el autor difiere con teorías anteriores, 212. – La teoría del interés expuesta de nuevo, 215. – Incertidumbres y fluctuaciones de la inversión, 217. – III. Demanda y oferta para la producción total, 219. –

John Maynard Keynes

2007-01-01

317

L'avifauna del Laghetto del Frassino (Peschiera del Garda, Verona, Veneto)  

Microsoft Academic Search

Ten years of ornithological research at Lake Frassino (located near Peschiera del Garda, Verona, Italy) have produced a check-list of the birds dwelling at this Site of Community Importance (S.I.C.) to be produced. Our surveys have revealed that this water basin where ducks stop al- most exclusively during the day represents, together with nearby Lake Garda, the most important wintering

MARCO MORBIOLI; MAURIZIO SIGHELE

318

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.

319

Evolucin del desarrollo y del costo de los sistemas fotovoltaicos en el mundo y en Chile  

E-print Network

Evolución del desarrollo y del costo de los sistemas fotovoltaicos en el mundo y en Chile Pontificia Universidad Católica de Chile Escuela de Ingeniería Departamento de Ingeniería Eléctrica IEE3372............................................................................................ 28 SMA Solar Technology

Rudnick, Hugh

320

l contenido econmico del XVI Con-greso del Partido Comunista Chino  

E-print Network

Organiza- ción Mundial del Comercio; Pekín ha sido ele- gida sede de los Juegos Olímpicos del 2008; el PCCh internacional, sino que la propia estruc- tura interna se configura según las prioridades de una economía

García-Berthou, Emili

321

Propostes i despropòsits: aspectes del gonellisme  

Microsoft Academic Search

Estudi sobre l'origen i la pervivència del gonellisme. Els autors n'exposen les constants ideològiques, que van del conservadorisme a l'extrema dreta, i fan una completa relació de les seves plataformes de difusió. L'anàlisi minuciosa d'aquest fenomen els porta a considerar el lligam entre el dialectalisme primigeni i el secessionisme anticatalanista que en deriva, així com a constatar la importància del

Guillem Calaforra; Sebastià Moranta

2005-01-01

322

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

323

Cirugía de los trastornos del comportamiento: el estado del arte  

PubMed Central

Introducción: La cirugía de los trastornos del comportamiento (CTC) se está convirtiendo en un tratamiento más común desde el desarrollo de la neuromodulación. Métodos: Este artículo es una revisión no sistemática de la historia, indicaciones actuales, técnicas y blancos quirúrgicos de la CTC. Dividimos su historia en 3 eras: la primera comienza en los inicios de la psicocirugía y termina con el desarrollo de las tícnicas estereotácticas, cuando comienza la segunda era. Ésta se caracteriza por la realización de lesiones estereotácticas. Nos encontramos transitando la tercera era, que comienza cuando la estimulación cerebral profunda (ECP) comienza a ser usada en CTC. Resultados: A pesar de los errores graves cometidos en el pasado, hoy en día, la CTC está renaciendo. Los trastornos psiquiátricos que se más frecuentemente se tratan con cirugía son: depresión refractaria, trastorno obsesivo-compulsivo y síndrome de Tourette. Además, algunos pacientes con agresividad fueron tratados quirúrgicamente. Hay varios blancos estereotácticos descriptos para estos trastornos. La estimulación vagal puede ser usada también para depresión. Conclusión: Los resultados de la ECP en estos trastornos parecen alentadores. Sin embargo, se necesitan más estudios randomizados para establecer la efectividad de la CTC. Debe tenerse en cuenta que una apropiada selección de pacientes nos ayudará a realizar un procedimiento más seguro así como también a lograr mejores resultados quirúrgicos, conduciendo a la CTC a ser más aceptada por psiquiatras, pacientes y sus familias. Se necesita mayor investigación en varios temas como: fisiopatología de los trastornos del comportamiento, indicaciones de CTC y nuevos blancos quirúrgicos. PMID:25165612

Yampolsky, Claudio; Bendersky, Damián

2014-01-01

324

La arquitectura del pastoreo: Uso del espacio y sistema de asentamientos en la Puna de Atacama (Susques)  

Microsoft Academic Search

RESUMEN El objetivo del trabajo es contribuir al conocimiento de la arquitectura del pastoreo en los Andes. El foco regio- nal del estudio es Huancar en el Departamento Susques (Jujuy, Argentina). En primer lugar se describen los sis- temas de asentamientos vinculados con las actividades pastoriles de Huancar y luego se presentan los esquemas del uso del espacio por parte

Barbara Göbel

2002-01-01

325

PROVA PRATICA Valutazione economica di un Piano attuativo del PRG  

E-print Network

PROVA PRATICA Valutazione economica di un Piano attuativo del PRG In presenza di un Piano attuativo'intera previsione volumetrica (commerciale e residenziale) del Piano attuativo, sia delle urbanizzazioni primarie e valutazione di compatibilita urbanistica del Piano attuativo #12;

Di Pillo, Gianni

326

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.

327

Monsters begat by quantifiers? Fabio Del Prete  

E-print Network

Monsters begat by quantifiers? Fabio Del Prete CNRS Lab CLLE-ERSS Toulouse Sandro Zucchi apparent consequence of this approach is that quantifiers and s are monsters in Kaplan's sense. We argue-00965284,version1-24Mar2014 #12;F. Del Prete - S. Zucchi Monsters begat by quantifiers? While some

Paris-Sud XI, Université de

328

Fisiología del embarazo: Interacción materno-infantil  

Microsoft Academic Search

ResumenEn los últimos años los datos han demostrado de qué manera el bienestar vitalicio depende considerablemente del crecimiento y el desarrollo intrauterinos durante la vida dentro del útero. El crecimiento fetal puede alcanzar únicamente su potencial íntegro mediante una interacción adecuada y armonizada entre la madre, la placenta y el feto. Este delicado equilibrio puede ser alterado por varios factores

Irene Cetin; Manuela Cardellicchio

2010-01-01

329

Las culturas políticas del republicanismo histórico español  

Microsoft Academic Search

Desde la perspectiva teórica denominada «Giro cultural», hemos tratado de repensar la formación del movimiento republicano español durante el siglo XIX, el cual tradicionalmente ha sido concebido de forma unívoca. En realidad, varios movimientos sociales coexistieron dentro del republicanismo español. Al menos desde tres culturas políticas republicanas (socialismo jacobino, demosocialismo y demoliberalismo) fueron movilizadas las clases populares españolas y se

Román Miguel González

2004-01-01

330

Svelato il codice genetico del lievito enologico  

Microsoft Academic Search

Primi al mondo, i ricercatori del 'The Australian Wine Research Institute' hanno completato il sequenziamento del genoma di un lievito enologico, descrivendo le 'ricette vitali' che danno forma all'amico dell'enologo. Questa ricerca apre la strada allo sviluppo di nuovi ceppi di lievito, in grado di offrire soluzioni innovative per il problema degli arresti di fermentazione, e di aumentare la gamma

Anthony R. Borneman; Angus H. Forgan; Paul J. Chambers; Isak S. Pretorius

331

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

332

Aspectos generales del concepto “capital humano”  

Microsoft Academic Search

ReSUMeN El presente artículo es la síntesis del debate de los autores sobre las transformaciones organizacionales basadas en el creciente predominio de los activos intangibles, especialmente del capital humano, para comprender las organizaciones económicas actuales en medio de sus contextos altamente exigentes y variables, como resultado de la fase inicial de una investigación general sobre el factor trabajo de las

Camilo Ernesto Tinoco Bernal; Sylvia Melissa Soler Mantilla

2011-01-01

333

Banco de Proyectos del Decanato de Extensin  

E-print Network

bienes a precios solidarios o al costo Aporte en especies a programas sociales determinados por el apoyan la propuesta 10. Resumen del presupuesto del proyecto. (Monto en BsF) Indique el financiamiento requerido para que la idea pueda lograr los objetivos mencionados. Costo total de la propuesta Monto

Vásquez, Carlos

334

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

335

COMUNICATO STAMPA Analisi Applicata del Comportamento (ABA) ed Autismo  

E-print Network

COMUNICATO STAMPA Analisi Applicata del Comportamento (ABA) ed Autismo Data Scadenza: 10 giugno 2014 ANALISI APPLICATA DEL COMPORTAMENTO (ABA) ED AUTISMO L'Università di Salerno ha pubblicati i bandi trattamento dei bambini con autismo secondo i criteri del metodo ABA (Analisi Applicata del Comportamento). I

Costagliola, Gennaro

336

D.R. n. n. 5024 del 1.08.2011n. 5024 del 1.08.2011n. 5024 del 1.08.2011n. 5024 del 1.08.2011 ClasseClasseClasseClasse LM-6 -Biologia  

E-print Network

.08.2011 ClasseClasseClasseClasse LM-6 - Biologia Nome del corsoNome del corsoNome del corsoNome del corso BIOLOGIA AMBIENTALE Nome ingleseNome ingleseNome ingleseNome inglese ENVIRONMENTAL BIOLOGY Lingua in cui si/2010, art. 14) Obiettivi formativi qualificanti della classe: LM-6 Biologia I laureati nei corsi di laurea

Malerba, Donato

337

PROPUESTA DELIQUIDACIÓN DEL CONTRATO CONSTRUCCIÓN NUEVO ALCANTARILLADO DEBOCAGRANDE-CARTAGENA  

Microsoft Academic Search

El Centro de Investigaciones para el Desarrollo (CID) de la Facultad de Ciencias Económicas fue invitado para que emitiera un concepto técnico sobre la liquidación del contrato celebrado el 20 de agosto de 1998 entre el Departamento Administrativo de Valorización del Distrito de Cartagena (DAVD) y la Compañía Alcantarillado Bocagrande S.A. El objetivo del contrato es la construcción del nuevo

Jorge Ivan GonzalesBorrero; Edna Cristina del SocorroBonilla Sebá; German GuerreroChaparro

2005-01-01

338

Departament de Cincies del Mar i Biologia Aplicada Vdeo promoci estudis en Cincies del Mar  

E-print Network

Departament de Ciències del Mar i Biologia Aplicada Vídeo promoció estudis en Ciències del Mar en la província alacantina. Departament de Ciències del Mar i Biologia Aplicada #12;Magazine Oceà nº curs està orientat a gestors ambientals, investigadors, persones amb formació acadèmica en Biologia

Escolano, Francisco

339

UNIVERSIDAD SIMON BOLIVAR SEDE DEL LITORAL  

E-print Network

UNIVERSIDAD SIMON BOLIVAR SEDE DEL LITORAL ESPECIALIZACIÓN EN TELECOMUNICACIONES DECANATO DE POSTGRADO DENOMINACIÓN: CÓDIGO: ASIGNATURA: LABOR. DE TELECOMUNICACIONES TI-7341 REQUISITOS: H. TEORÍA: H Laboratorio de Telecomunicaciones, el estudiante deberá haber obtenido destrezas prácticas en los

Vásquez, Carlos

340

PROT. N. 00113811 Del 06 luglio 2006  

E-print Network

'anno 2006 dei bilanci di enti ed organismi pubblici, ivi comprese le Università e i Dipartimenti, relativi impegnate alla data di entrata in vigore del decreto. Lo stesso Decreto Legge dispone che le somme

Milano-Bicocca, Università

341

Balance del año teatral 1972 en Lima.  

E-print Network

universitarios como el de la Universidad Villarreal y el de la Universidad San Martín de Porres y con grupos universitarios voca- cionales, como son el TUNI (Teatro de la Universidad Nacional, de Ingeniería) el ISANM o grupo de teatro del Instituto Superior de...), 33-41. 12. El Ingeniero Arturo Nolte, también director de producción del Teatro Nacional Popular, quien gentilmente nos brindó esta información, en entrevista celebrada en Lima, el 8 de mayo de 1972 puso de relieve que los grupos universitarios...

Cajiao Salas, Teresa

1974-10-01

342

La evolucion del modernismo en Puerto Rico  

E-print Network

elementos estilis- ticos: la belleza plastica, la musicalidad, el croma- tismo, el sensualismo, el exotismo, la evasion, el sen- tido cosmopolita y el dualismo. El modernismo ademas in- novo la metrica mediante el uso de los siguientes metros: los... por resaltar lo exotico, lo extravagante y lo pictorico. Hace uso de la parodia y de la shtira, pero cuidando de la forma y del ritmo del verso. De igual modo, Amado Nervo ejercio su influencia mediante su poesia existencialista y espiri- tualista...

Gonzalez-Hernandez, Miriam Mercedes

1989-01-01

343

Reseña del VIII Festival Internacional de Teatro  

E-print Network

los diferentes medios del país. Este vacío que fue protuberante se debió a la falta de recursos económicos para sostener esta clase de invitados. Mas como efecto positivo se percibió que durante la semana del evento el Festival Internacional no giró... una acción viva que requiere de crónica aparte. El Teatro Taller de Colombia merece página aparte por la validez e importancia de su trabajo que es toda una propuesta que cobija factores de indudable calidad, en especial su "circo invisible" que...

Dí az, Né stor Gustavo

1986-10-01

344

Gonadal dysgenesis in del (18p) syndrome  

SciTech Connect

We report on a girl with syndromal gonadal dysgenesis and a de novo del (18p). Genetic factors controlling gonadal development are located not only on the X chromosome, but also on autosomes. The present case suggests that one of these genes is situated on 18p. We conclude that patients with del (18p) syndrome should be evaluated for gonadal dysgenesis. 16 refs., 3 figs.

Telvi, L.; Ion, A.; Fouquet, F. [Hospital Saint Vincent de Paul, Paris (France)] [and others

1995-07-17

345

Pgina 1 de 18 CDIGO DE CONDUCTA DEL CENTRO DE  

E-print Network

Página 1 de 18 C�DIGO DE CONDUCTA DEL CENTRO DE INVESTIGACION Y DE ESTUDIOS AVANZADOS DEL INSTITUTO CONDUCTA: I. Conocimiento y aplicación de las leyes y normas. 1 II. Uso del cargo público. 2 III. Uso y T�RMINOS. 13 #12;Página 2 de 18 C�DIGO DE CONDUCTA DEL CENTRO DE INVESTIGACION Y DE ESTUDIOS AVANZADOS DEL

346

Calidad de Imagen del Telescopio UNAM212  

NASA Astrophysics Data System (ADS)

El telescopio UNAM2l2, del Observatorio Astronómico Nacional, situado en la Sierra de San Pedro Mártir (Baja California, México), cumplira en un futuro muy cercano siete años de uso para fines de investigación astronómica. Aunque en este tiempo no se ha efectuado un estudio sistemático acerca de su comportamiento óptico y de los factores que influyen en la calidad de las imágenes, se han realizado pruebas diversas, estudios parciales y reuniones especificas, cuyos resultados no siempre se han difundido ampliamente y generalmente no se han presentado por escrito. Es por ello que hemos creido necesario intentar una recopilación de la información existente para poder con ella establecer un diagnóstjco que, aunque no sea definitivo, sirva de base para futuros trabajos tendientes a optimizar el comportamiento óptico del telescopio. Es evidente que un buen número de las conclusiones que se presentan son resultado del trabajo de muchas personas ó de esfuerzos colectivos. Asimismo, hemos tratado de localizar información bibliográfica que pueda ser de utilidad. Nuestro objetivo primordial ha consistido en centrarnos en la óptica del telescopio y su calidad, pero también se han considerado otros aspectos que puedan afectar las imágenes obtenidas tales como: celda del primario, `seeing' local y externo, flexiones posibles en la estructura mecánica del telescopio, etc.

Cobos, F. J.; Teiada de Vargas, C.

1987-05-01

347

Los orígenes del Partido del Socialismo Democrático (1989-1993): el ave fénix roja en Alemania  

Microsoft Academic Search

El Partido del Socialismo Democrático (Partei des Demokratischen Sozialismus), surgido de la descomposición interna del SED (Sozialistiscbe Einbeitspartei Deutschlands), es un caso relevante de adaptación de los partidos únicos en los regímenes comunistas a la democracia plurípar-tidista. Dadas las peculiaridades de la transición en la República Democrática de Alemania, acelerada por su rápida integración en la República Federal, el SED

Ricardo Martín de la Guardia

2005-01-01

348

Simulación numérica del transporte del herbicida glifosato en la zona no saturada  

Microsoft Academic Search

RESUMEN. La simulación numérica junto con los experimentos de campo constituyen herramientas imprescindibles para el estudio del transporte de agua y de sustancias contaminantes en el subsuelo. El objetivo de este trabajo es presentar un modelo numérico para describir la migración de un contaminante sometido a procesos de adsorción y de degradación en la zona no saturada (ZNS) del terreno.

L. Guarracino; L. Candela Lledó; J. E. Santos

1999-01-01

349

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

350

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.

351

Experiencias en la incorporación del enfoque poblacional en la planeación del desarrollo territorial. Memorias  

Microsoft Academic Search

Este documento contiene las ponencias presentadas durante el Encuentro Experiencias en la incorporación del enfoque poblacional en la planeación del desarrollo territorial realizado en Bogotá los días 6 y 7 de noviembre de 2008 en la Universidad Externado de Colombia. El evento fue organizado por el Fondo de Población de las Naciones Unidas -UNFPA-, el Departamento Nacional de Planeación -DNP-,

Yolanda Bodnar Contreras

352

VI CONGRESO DEL CEISAL Toulouse, del 30 de junio al 3 de Julio de 2010  

E-print Network

-30Jun2010 #12;Identificación de fortalezas y debilidades del G8+5 ante la crisis energética 2 RESUMEN Cumbre 2008 de Ministros de Finanzas de la Mancomunidad Británica de Naciones celebrada del 6 al 8 de

Paris-Sud XI, Université de

353

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

354

Balances energéticos y uso del sueloen la agricultura catalana: una comparación entre mediados del siglo XIX y finales del siglo XX  

Microsoft Academic Search

El presente trabajo analiza y compara, desde la perspectiva analítica del metabolismo social, los usos del suelo y los balances energéticos derivados de estos usos de los sistemas agrarios de cinco municipios de la comarca catalana del Vallès, en dos momentos históricos que ilustran las características y magnitud de las transformaciones que se han producido en los sistemas agrarios catalanes

Xavier Cussó; Ramon Garrabou; José Ramon Olarieta; Enric Tello

2006-01-01

355

Digitalización de diapositivas del Sol en H ?  

NASA Astrophysics Data System (ADS)

El objetivo de este trabajo ha sido el de obtener imágenes digitalizadas de las diapositivas tomadas del Sol en luz de hidrógeno de la línea correspondiente a H?, y de esta manera llegar a convertir las mismas a un archivo digital para poder ser tratadas luego por computadora y poder contabilizar con exactitud, mediante un programa adecuado para tal fin, las zonas activas del Sol en la imagen digitalizada. En principio, para llegar a esto se pensó en la utilización de medios accesibles, y como detector se utilizó un fototransistor ubicado dentro de un soporte rectangular sobre dos ejes de desplazamiento X e Y. Se han obtenido con este procedimiento imágenes de buena calidad, construídas a partir de tres datos digitalizados en cada barrido que aportan la posición X e Y y la intensidad del pixel en ese punto indicada en 255 tonos de grises.

Missio, H.; Montenegro, C.; Montenegro, R.

356

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.

357

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

358

Polo Universitario Imperiese Scienze del turismo: impresa, cultura e territorio  

E-print Network

-PSI/01 Psicologia del turismo (mod. 1 con M-PSI/01) 6 caratterizzante BIO/08 Antropologia per il turismo (mod. 2 con BIO/08) 6 affini SPS/07 Sociologia del turismo 9 caratterizzante L-ART/05 Antropologia

Robbiano, Lorenzo

359

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.

360

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.

361

La reconstrucción del seno después de una mastectomía  

Cancer.gov

Hoja informativa que describe la reconstrucción del seno (mama) después de una mastectomía. Contiene información sobre las opciones quirúrgicas, los cuidados de seguimiento y los exámenes de detección del cáncer de seno después de la reconstrucción.

362

Manuel Garca Snchez-Colomer -1 Evaluacin del impacto ambiental  

E-print Network

Manuel García Sánchez-Colomer - 1 Evaluación del impacto ambiental Temas 12 - 13 Tema 13 Evaluación del impacto ambiental Temas 12 - 13 Factor del medio: medio biótico · Vegetación · Fauna terrestre ambiental Temas 12 - 13 Medio biótico: Vegetación ESTUDIO DE VEGETACIÓN DE RIBERA ­ ESTUDIO DE HÁBITATS DE

Espigares, Tíscar

363

Estrategias cognitivo-conductuales para el manejo del craving  

Microsoft Academic Search

En el presente trabajo se revisaron los aspectos genera- les del craving y se destacó su importancia para la adhe- rencia al tratamiento en adicciones. De igual manera se revisaron las diferentes estrategias cognitivo-conductua- les para el manejo del craving, las cuales incluían: detención del pensamiento, técnicas de distracción, con- trol y programación de actividades, entrenamiento en relajación, técnicas de

Iván González Salazar

2004-01-01

364

Guida alla compilazione del Piano economico on line  

E-print Network

Guida alla compilazione del Piano economico on line #12;Attenzione Questa guida fornisce indicazioni pratiche per la compilazione del Piano economico on line. Per avere indicazioni più generali sulla formulazione del Piano economico si raccomanda di fare riferimento a: Guida alla presentazione (http

De Cindio, Fiorella

365

Piano Lauree Scientifiche: Aspetti matematici del Rudiger Achilles  

E-print Network

Piano Lauree Scientifiche: Aspetti matematici del GPS R¨udiger Achilles Universit`a di Bologna Bologna, 3 Febbraio 2014 Piano Lauree Scientifiche: Aspetti matematici del GPS R¨udiger Achilles Bologna essere d. Piano Lauree Scientifiche: Aspetti matematici del GPS R¨udiger Achilles Bologna, 3 Febbraio

Achilles, Rüdiger

366

Hoja informativa sobre la calidad del aire interior  

E-print Network

promover la salud y la calidad de vida mediante la prevención y el control de las enfermedades, lasHoja informativa sobre la calidad del aire interior La mala calidad del aire interior proviene de de uso doméstico como limpiadores y pesticidas Cómo mejorar la calidad del aire interior · Abra las

367

EL TURISMO ELECTRÓNICO, UNA NECESIDAD PARA LAS EMPRESAS DEL SECTOR  

Microsoft Academic Search

La importancia y la necesidad de la utilización del Comercio Electrónico en la industria turística ayuda a mejorar las operaciones tradicionales practicadas en los negocios, tanto en la estrategia empresarial como en la reingeniería del negocio turístico. El hecho de que predominen las pequeñas y medianas empresas en el sector implica que la utilización del e-Commerce no se ha extendido

Ernesto Manuel Conde Pérez; Nel Enrique Cristian Schmidt Cornejo; Ileana Ochoa Llamas

2011-01-01

368

COMUNICATO STAMPA Nuove frontiere del Corso di Laurea in Fisioterapia  

E-print Network

in Fisioterapia intende promuovere un'ulteriore analisi della formazione universitaria del Fisioterapista rinnovamento importante della Formazione universitaria del Fisioterapista, non più ulteriormente differibile universitaria e nel profilo del Fisioterapista. E' stato richiesto l' accreditamento E.C.M. LA PARTECIPAZIONE AL

Costagliola, Gennaro

369

Departament de Filosofia del Dret i Dret Internacional Privat Presentaci  

E-print Network

Departament de Filosofia del Dret i Dret Internacional Privat Presentació El Departament de Filosofia del Dret i Dret Internacional Privat està compost per les següents àrees de coneixement: Tauler d Departament de Filosofia del Dret i Dret Internacional Privat preguen als seus alumnes que es comuniquen amb

Escolano, Francisco

370

Tratamiento biológico del lixiviado generado en el relleno sanitario \\  

Microsoft Academic Search

2 *d; además, este sistema presentó gran estabilidad frente a variaciones importantes en cuanto a las características del lixiviado y ausencia de olores desagradables. Los porcentajes de remoción de DQO en el reactor UASB eran muy variables, con picos bajos y caídas muy marcadas, que indican que no se presentaba un funcionamiento óptimo del proceso durante la mayor parte del

Alexander Álvarez Contreras; John Hermógenes; Suárez Gelvez

2006-01-01

371

Análisis del Proceso Software Basado en Modelos de Producción Industrial  

Microsoft Academic Search

La modelización del Proceso Software constituye un marco de referencia para la organización de las actividades que involucran todas las etapas del desarrollo, tendente a la resolución de problemas que el propio desarrollo de software plantea y genera a medida que evoluciona. La modelización del proceso se hace mas compleja a medida que el desarrollo tecnológico, metodológico y, fundamentalmente la

Alicia Mon

372

Recalibrando la medición del balance estructural en Chile  

Microsoft Academic Search

El presente resumen de políticas realiza una revisión sistemática de la metodología de estimación del Balance Estructural (BE) en Chile. Esta revisión no sólo recapitula y evalúa la justificación de la metodología de cálculo del BE actual o las pasadas, sino que explora diversas alternativas de mejoramiento, en la perspectiva de elevar la calidad, transparencia y estabilidad del BE como

Mario Marcel; Mabel Cabezas; Bernardita Piedrabuena

2012-01-01

373

ESPECIALIZACIN EN GESTIN AMBIENTAL Objetivo del programa  

E-print Network

ESPECIALIZACIÓN EN GESTIÓN AMBIENTAL Objetivo del programa La Especialización en Gestión Ambiental identificar, en un mundo cambiante, en lo social, en lo económico y en lo ambiental, las medidas de prevención, mitigación y resolución de problemas de carácter ambiental, a fin de contribuir con el desarrollo sostenible

Vásquez, Carlos

374

APUNTES PARA UN ESTUDIO DEL DISEÑO INDUSTRIAL  

Microsoft Academic Search

La máquina es quizá el factor dominante de nuestra época. Desde la primera mitad del XIX se desarrolla une nuevo sistema de acción sobre la materia y de producción de objetos permitiendo la multiplicación de objetos consecuencia de la producción en serie. El diseño industrial es así la forma característica de la producción de objetos de la sociedad industrial, es

Ignacio Casado Galván

2009-01-01

375

Exámenes selectivos de detección del cáncer colorrectal  

Cancer.gov

Un ejemplo excelente del poder de la investigación de prevención es el progreso sustancial que hemos logrado en la reducción de la incidencia y muerte por cáncer colorrectal, con nuevos conocimientos que iluminan el camino a incluso mayores reducciones en un futuro cercano.

376

Self Interacting Markov chains P. Del Moral  

E-print Network

-Sud Ouest, France 2 / 27 #12;Self interacting processes in biology and engineering Biology : Genetic type, bayesian learning, filtering, and spectral analysis of Feynman-Kac-Schroedinger operators. Some important-Boltzmann-Gibbs transformation : G : E [0, [ with µ(G) > 0 G (µ)(dx) = 1 µ(G) G(x) µ(dx) P. Del Moral (INRIA Bordeaux) INRIA

Del Moral , Pierre

377

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

378

VIII Encuentro Nacional de Teatro del CLETA  

E-print Network

músicos y cantantes. Unos gozan de más experiencia dentro del género y de más conocimiento técnico que otros; sin embargo, lo que está por encima de algunas posibles deficiencias técnicas es la voluntad firme de los "Cletos" de hacer teatro, de...

Frischmann, Donald H.

1983-10-01

379

EXCEPTIONAL SHEAVES ON DEL PEZZO SURFACES  

Microsoft Academic Search

In the present paper exceptional sheaves on del Pezzo surfaces are studied, and a description of rigid bundles on these surfaces is given. It is proved that each exceptional sheaf can be included in a complete exceptional collection. Furthermore, it is shown that all such collections can be obtained from each other by means of a sequence of standard operations

S. A. Kuleshov; D. O. Orlov

1995-01-01

380

PASO DEL NORTE SUMMER OZONE STUDY  

EPA Science Inventory

The Paso del Norte Summer Ozone Study was designed to evaluate potential control strategies for their efficacy in reducing ozone and carbon monoxide concentrations in the El Paso-Ciudad Juarez-Sunland Park international airshed of Texas, New Mexico, and Chihuahua. A field study ...

381

Sebastin Nieto Parra* ESTABILIDAD DEL SISTEMA  

E-print Network

Sebastián Nieto Parra* ESTABILIDAD DEL SISTEMA FINANCIERO Y REGULACI�N DE CAPITAL: EL CASO DE LOS financieros que pueden subsanar la fragilidad de los sistemas financieros y favorecer así la estabilidad de éstos. Palabras clave: sistema financiero internacional, instituciones financieras y crediticias, crisis

Paris-Sud XI, Université de

382

Enhancing compressor distortion tolerance by asymmetric stator control  

NASA Technical Reports Server (NTRS)

This paper describes a preliminary study of a method for increasing compressor tolerance in circumferential distortion through asymmetric vane stagger control. The changes in vane stagger about the circumference are used to increase compressor pressure rise and flow capability over part of the annulus and decrease these over the rest. The average pressure rise and flow thus remain roughly constant but the velocity distortion is reduced (and can even be made zero). Calculations are carried out to show the magnitude of the vane motions that must be used, and it is found that significant increases in distoriton attenuation can be achieved with realistic vane swings. In addition, the asymmetric vane stagger scheme leads to a substantial decrease in stall pressure rise loss due to inlet total pressure distortion. This type of control strategy appears worthy of further investigation, both theoretical and experimental.

Chen, G. T.; Greitzer, E. M.; Epstein, A. H.

1987-01-01

383

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

384

Stator for a rotating electrical machine having multiple control windings  

DOEpatents

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 bias field.

Shah, Manoj R. (Latham, NY); Lewandowski, Chad R. (Amsterdam, NY)

2001-07-17

385

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

386

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

387

El teatro argentino del año 2000 y el teatro del futuro  

E-print Network

concepto deconstructivo, con su manejo de la contaminación textual, señaló el advenimiento del intertexto posmoderno en nuestro teatro. Las nociones que Jencks (97) postula para la arquitectura posmoderna pueden emplearse para acercarse al teatro de... incluyen en esta tendencia.10 Ellos, junto a otros creadores, están protagonizando desde los primeros años de la presente década una "nueva entrada al mundo" del teatro argentino. En un ambiente limitado durante mucho tiempo a "vivir con lo nuestro...

Pellettieri, Osvaldo

2000-10-01

388

Usos del sòl i tendències de transformació a la comarca del Baix Llobregat  

Microsoft Academic Search

A partir de les dades sobre sol urbà i sol urbanitzable programat, per usos, als municipis del Baix Llobregat, s'analitzen la realitat i les potencialitats en l'ocupació del sol a la comarca. Tot seguit es passa a descriure les principals tendències de transformació en aquest camp per a un futur proper, que s'associen, fonamentalment, als grans projectes de creació d'infraestructures

Javier Sáez

2008-01-01

389

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.

390

Ttol: CONCURS PER A LA RENOVACI DEL LOGOTIP DEL PROGRAMA DACCI TUTORIAL (P.A.T.) DE LA FACULTAT  

E-print Network

DE FILOSOFIA I LLETRES Categoria: CONVOCAT�RIES I CONCURSOS �rgan: Facultat de Filosofia i Lletres RENOVACI� DEL LOGOTIP DEL PROGRAMA D´ACCI� TUTORIAL (P.A.T.) DE LA FACULTAT DE FILOSOFIA I LLETRES CONCURSO de Filosofia i Lletres convoca aquest concurs que té per objecte l´actualització distintiva del

Escolano, Francisco

391

Aproximación al cálculo del crecimiento real de Colombia: aportes metodológicos para la inclusión en las cuentas nacionales de los impactos del  

Microsoft Academic Search

Resumen El sistema de contabilidad integrada considera el problema del agotamiento de los recursos naturales. En este trabajo se analiza la diferencia entre este sistema y el de cuentas nacionales utilizando datos del sector minero en Colombia para gas natural y carbón. Los resultados muestran que al incorporar los impactos del agotamiento del gas natural y del carbón el PIB

Michee Lachaud; Jorge Maldonado

2011-01-01

392

Wind turbine/generator set having a stator cooling system located between stator frame and active coils  

DOEpatents

A wind turbine comprising an electrical generator that includes a rotor assembly. A wind rotor that includes a wind rotor hub is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle via a bearing assembly. The wind rotor hub includes an opening having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity inside the wind rotor hub. The spindle is attached to a turret supported by a tower. Each of the spindle, turret and tower has an interior cavity that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly.

Bevington, Christopher M.; Bywaters, Garrett L.; Coleman, Clint C.; Costin, Daniel P.; Danforth, William L.; Lynch, Jonathan A.; Rolland, Robert H.

2012-11-13

393

ZAP70 Expression Within del6q21, del11q13 and del17p13 Cytogenetic Subgroups of Iranian Patients with Chronic Lymphocytic Leukemia  

PubMed Central

Background: B-cell chronic lymphocytic leukemia (B-CLL) is the most common form of leukemia in adults. Some reports showed that expression of ZAP70 gene and chromosomal abnormality are two prognostic factors in management of B-CLL Objectives: In this study, we determined ZAP70 mRNA expression level in the del17p13, del6q21 and del11q13 subgroups of Iranian B-CLL patients to investigate prognostic value of ZAP70 expression. Patients and Methods: In this cross-sectional study, fluorescence in situ hybridization analysis was carried out on 66 Iranian B-CLL patients. Zap70 mRNA expression was evaluated by using Real Time RT-PCR. Results: Molecular analysis showed that ZAP70 expression increased 2.46 fold in the del11q13 subgroup, 2.87 fold in the del17p13 and 1.87 fold in the del6q21, compared to the 15 patients in the control group. Comparison of standard deviation and mean of the ZAP70 expression profile within the subgroups showed more variability among the cases of the del11q13 and del17p13 versus tight clustering for the del6q21. Therefore, there is a relation between del6q21 aberrations; which has good prognosis with normal levels of ZAP70 expression. Conclusions: The results of ANOVA test showed that ZAP70 expression gene was significantly increased in del17p13 and del11q13 subgroups compared to control group. Thus, ZAP70 may play an important role in the prognosis of B-CLL patients.

Jafari Ghahfarokhi, Hamideh; Ashoori, Saeede; Akbari, Mohamad Taghi; Lotfizadeh, Masoud; Karimi, Ali; Teimori, Hossein

2014-01-01

394

Adherencia del tratamiento antibiótico en los cuadros  

Microsoft Academic Search

OBJETIVO: Evaluar la adherencia del tratamiento antibiótico observada en pacientes con cuadros infecciosos no complicados y tratados con diversas pautas antibióticas.\\u000aDISEÑO: Estudio observacional y prospectivo desde 2003 hasta 2008. ÁMBITO DE ESTUDIO: Dos centros de atención primaria de Cataluña.\\u000aSUJETOS: Pacientes de 18 años o más con sospecha de infección de etiología bacteriana de faringe, tracto respiratorio inferior, tracto

Nuria Sierra Montalbán; Silvia Hernández Anadón; Carles Llor Vilà; Ana Moragas Moreno; Marta Hernández Anadón; Carolina Bayona Faro

2010-01-01

395

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...

1990-04-01

396

III Festival del Siglo de Oro (Chamizal)  

E-print Network

y los Estados Unidos, administrado por el Servicio Nacional de Parques como homenaje a la buena voluntad interamericana. Cuenta con una amplia sala de teatro donde se realizan muchas funciones culturales bilingües. Allá se celebró del 7 al 18 de... Tirso de Molina. Los grupos 112 LATIN AMERICAN THEATRE REVIEW participantes fueron invitados desde México, Venezuela, y la región sureña de los Estados Unidos. Se dividieron en dos categorías, grupos académicos y de reper torio, y compitieron por...

Jaraba-Pardo, E.

1978-04-01

397

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

398

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

399

SISTEMA PARA GESTIONAR LA ACTIVIDAD CIENTÍFICA DEL DEPARTAMENTO DE INFORMÁTICA DE LA UNIVERSIDAD DE GUANTÁNAMO  

Microsoft Academic Search

El sistema para gestionar la actividad científica del Departamento de Informática de la Universidad de Guantánamo surge debido a la necesidad de gestionar de manera más rápida, segura y eficaz los procesos que se desarrollan actualmente en dicho centro. Fue desarrollado utilizando los lenguajes PHP del lado del servidor con CodeIgniter como framework y JavaScript del lado del cliente. Se

Denis Boizan Romero

2012-01-01

400

Consejera de Administraciones Pblicas y Portavoz del Gobierno Direccin General de Modernizacin  

E-print Network

. En esta segunda vía se inscribe la iniciativa del Repositorio Institucional del Principado de su autoarchivo los resultados de la investigación en el Repositorio Institucional del Principado de, favoreciendo el aumento del impacto del trabajo desarrollado por los investigadores y las instituciones

401

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

402

An evening at "La Clinica del Pueblo".  

PubMed

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

Shefsky, M L

1986-01-01

403

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

404

Manual del espectrógrafo multifunción de Bosque Alegre  

NASA Astrophysics Data System (ADS)

Este manual consta de 120 páginas y resume las características del Espectrógrafo Multifunción instalado en el telescopio de 1.54 m de la Estación Astrofísica de Bosque Alegre. En este trabajo se describen, además, las técnicas a emplear para su puesta a punto y la secuencia de operaciones para la obtención de datos en cada uno de los modos que ya se encuentran en funcionamiento. Parte de este trabajo se realizó con el apoyo de la Asociación Argentina de Astronomía, a través de becas otorgadas a R.D. y S.P..

Díaz, R.; Paolantonio, S.; Carranza, G.; Goldes, G.

405

EXPERIENCIAS EN LA ENSEÑANZA DEL COMERCIO ELECTRÓNICO EN LA UNIVERSIDAD DE PINAR DEL RÍO  

Microsoft Academic Search

El desarrollo del Comercio Electrónico es uno de los objetivos de la política de informatización de la sociedad cubana, y en este sentido se labora en la creación de infraestructuras y la capacitación de los recursos humanos necesarios. Las universidades cubanas ya incluyen en sus planes de estudio este tema, cuyo aprendizaje contribuye a formar profesionales de mayor calidad para

Lisbet Martínez Gil

2010-01-01

406

Scheda del programma definitivo ITPS 2013-2014-Prof.ssa Antonietta Lanza Obiettivo del corso  

E-print Network

specifiche in SILAD preparatorie alla prova di laboratorio. E' pianificata una prova in itinere a metà corso prova di laboratorio e una prova scritta. La prova di laboratorio (prova parziale in ESSE3) mira analisi molto limitata) mediante un programma in linguaggio Java. L'esito della prova di laboratorio è del

Malerba, Donato

407

Huave de San Mateo del Mar, Oaxaca (Huave of San Mateo del Mar, Oaxaca).  

ERIC Educational Resources Information Center

This document is one of 17 volumes on indigenous Mexican languages and is the result of a project undertaken by the Archivo de Lenguas Indigenas de Mexico. This volume contains information on Huave, an indigenous language of Mexico spoken in San Mateo del Mar, in the state of Oaxaca. The objective of collecting such a representative sampling of…

Mexico Coll. (Mexico City)

408

El crimen como oficio: una interpretación del aprendizaje del delito en Colombia  

Microsoft Academic Search

El objetivo de este trabajo es proponer un marco de análisis que permita entender el aprendizaje del delito en Colombia. El articulo supone que el delito puede ser entendido como un actividad que requiere cierta experticia. En esta medida, el crimen requiere una compleja y extensa preparación, lo cual va en contra de la creencia de que cualquier persona, en

Isaac De León Beltrán; Eduardo S. Albarán

2003-01-01

409

CARACTERÍSTICAS DEL DIRECTIVO RESPONSABLE DEL ÁREA INTERNACIONAL Y RESULTADO EXPORTADOR DE LAS EMPRESAS INDUSTRIALES  

Microsoft Academic Search

RESUMEN La creencia de que la intensidad exportadora de las empresas puede estar ocasionada por barreras internas ha generado un cuerpo de investigación sobre la influencia de las características de los directivos responsables del área internacional (DRAI) en el inicio de las operaciones de exportación, la adopción de un papel activo en la intensificación de las exportaciones o el logro

Del Río Araújo

2005-01-01

410

Análisis del dispositivo de balón coil para la oclusión del Ductus Arterioso Persistente  

Microsoft Academic Search

RESUMEN: El ductus arterioso persistente (PDA) es uno de los defectos cardiacos congénitos más comunes. Consiste en una comunicación vascular anormal durante la vida extrauterina, entre la aorta descendente y la arteria pulmonar izquierda. El PDA puede llevar al desarrollo de complicaciones importantes como hipertensión pulmonar, edema pulmonar y endocarditis bacteriana. Actualmente el manejo del PDA se hace por medio

A. C. Silva; J. C. Briceño; A. García

411

Evaluacin de Diseo 2009 del Programa I. DATOS DE IDENTIFICACIN DEL PROGRAMA  

E-print Network

Presupuesto B00 Instituto Politécnico Nacional, Yoloxóchitl Bustamante Díez , Directora General D00 Instituto este análisis puedan retroalimentar el diseño y la gestión del programa VII. Costo total de la evaluación externa, especificando la fuente de financiamiento. Costo total: $500,000 Fuente de financiamiento

412

EL PERRO DEL HORTELANO: DEFINIENDO EL ROL EMPRESARIAL DEL ESTADO EN LATINOAMÉRICA  

Microsoft Academic Search

Las fuentes de agua fresca son abundantes en el Perú, sin embargo los peruanos tienen el segundo nivel de acceso más bajo a agua potable y desagüe en Sudamérica. Sólo el 72 por ciento de los hogares tienen acceso a agua potable por cañería (pero no se atreven a tomarla del grifo) y sólo el 51 por ciento tiene acceso

Carlos Patrón

2006-01-01

413

EL PLURIVERSO DEL AGUA. DISCURSOS, IMAGINARIOS Y CONTRATOS EN EL CONFLICTO DEL AGUA  

Microsoft Academic Search

Un buen modo de abordar el conflicto del agua consiste en prestar atención al nivel de los discursos. De este modo se puede poner de manifiesto los modos tan distintos de experimentar e interpretar la realidad que tienen los actores que en tal conflicto inter- vienen. Ahora bien, como algunos discursos enunciados no tienen el suficiente poder retórico y político

J. Ángel B ERGUA

414

EFICIENCIA DEL USO DEL AGUA EN LA PRODUCCIÓN AGRICOLA EN GUATEMALA  

Microsoft Academic Search

Los estudios de ciclo de vida, hasta hoy en día, han tenido en cuenta principalmente, los flujos de energía y materiales, no existiendo acuerdo en como tratar el recurso agua, siendo éste uno de los factores que deberían considerarse, especialmente en los sistemas de producción agrícolas. El manejo del agua en agricultura, asociado a su escasez, es uno de los

Willian E. de León; Asunción Antón

415

Respuestas a las preguntas del ejercicio de ``La Expansi'on del Universo y la Ley de Hubble''  

E-print Network

Respuestas a las preguntas del ejercicio de ``La Expansi'on del Universo y la Ley de Hubble'' --La constante de Hubble, H, debe de salir alrededor de 70 km s \\Gamma1 Mpc \\Gamma1 . El tiempo transcurrido desde el inicio del Universo ser'a t = D=V . Pero por otra parte, la constante de Hubble es H = V=D, de

Rodriguez, Luis F.

416

Influence of capillary pressure on CO2 storage and monitoring Juan E. Santos, CONICET, Instituto del Gas y del Petroleo, Facultad Ingenieria, Universidad de Buenos Aires,  

E-print Network

del Gas y del Petr´oleo, Facultad Ingenier´ia, Universidad de Buenos Aires, Department of Mathematics´ias, Instituto del Gas y del Petr´oleo, Facultad Ingenier´ia, Universidad de Buenos Aires, Jos´e M. Carcione

Santos, Juan

417

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.

418

78 FR 74008 - Amendment of Class E Airspace; Del Rio, TX  

Federal Register 2010, 2011, 2012, 2013, 2014

...controlled airspace at Laughlin AFB, Del Rio, TX. Environmental Review The...extension. * * * * * ASW TX E3 Del Rio, TX [Amended] Del Rio, Laughlin AFB, TX (Lat. 29...Fort Worth, Texas, on November 25, 2013. David P. Medina,...

2013-12-10

419

La formación del Partido Conservador: la fusión conservadora  

Microsoft Academic Search

Aunque la Restauración, en cuanto a su historia política, es un período muy agraciado por lo que a atención historiográfica se refiere, todavía algunos aspectos del período están bajo el dominio de lugares comunes discutibles. Uno de ellos es la formación del Partido Conservador. En este artículo se sostiene que la fuerza formada por Antonio Cánovas, si bien hunde sus

Fidel Gómez Ochoa

2003-01-01

420

Vida Arti cial: Estudio y an alisis del programa SWARM  

E-print Network

Jim#19;enez Introducci#19;on En este libro se realiza un estudio, a nivel introductorio, del campo de descubrir aplicaciones en una rama fundamental del citado campo: la de los Mundos Arti#12;ciales. El texto, y que proporcionaron aut#19;enticos hitos en este campo. A continuaci#19;on, se presenta el programa

Jiménez, Mario de J. Pérez

421

El sector industrial del Tolima: aproximación histórica, estructura y dinámica  

Microsoft Academic Search

En virtud de las exenciones tributarias y arancelarias que dispuso el gobierno con el fin de reactivar la economía de la zona afectada por la erupción del volcán-nevado del Ruiz en 1985, la industria tolimense experimentó un período de auge entre 1990 y 1995, durante el cual creció la base industrial y se logró cierto grado de diversificación; sin embargo,

Alvaro Augusto Campos Martínez

2004-01-01

422

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 tráileres Los Centros para el Control y la Prevención de Enfermedades (CDC) responden a las preocupa ciones que usted pueda tener sobre la calidad del aire y el formaldehído en los tráileres de FEMA. Usted

423

Decoding F508del misfolding in cystic fibrosis.  

PubMed

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

424

María Asunción Requena: Éxito e historia del teatro  

E-print Network

brujos y del futuro puente a construir; de las mujeres casaderas y de aquellas cuyos maridos partieron a la Patagonia. También hay sahumerios, huso y lana. ( Las Ultimas Noticias. 29 de octubre, 1989, p. 32) En junio del 89, Eduardo Guerrero...

Villegas, Juan

1995-04-01

425

> IRD/J. Orempuller Recursos y pilotaje del instituto  

E-print Network

44 45 s s s > © IRD/J. Orempuller #12;Recursos y pilotaje del instituto s Los medios financieros 46 disfrutado del apoyo de una importante movili- zación de los recursos financieros y de los medios humanos su patrimonio inmobilia- rio e invirtiendo en equipos científicos. medios financieros E L PRESUPUESTO

426

UNIVERSIDAD NACIONAL AUTNOMA DE MXICO Datos del plan de estudio  

E-print Network

Taekwondo Dirigido a: Entrenadores de la DGADyR, Comunidad Universitaria y Público General Síntesis o descripción breve: El curso le permite al interesado explicar el desarrollo histórico del taekwondo tanto en su país de origen, como en México, aplicar las diferentes técnicas del taekwondo para establecer la

Islas, León

427

ON THE MOTIVE OF A QUOTIENT VARIETY SEBASTIAN DEL BA ~  

E-print Network

ON THE MOTIVE OF A QUOTIENT VARIETY SEBASTIAN DEL BA ~ NO ROLLIN AND VICENTE NAVARRO AZNAR En with the realization functors and Chow groups. Recently, in the case char k = 0, Guill'en and Navarro Aznar have given. DEL BA ~ NO ROLLIN AND V. NAVARRO AZNAR group, K 0 M k , these decompositions were considered by Denef

Politècnica de Catalunya, Universitat

428

Analisi termica per la valutazione del danno negli acciai  

Microsoft Academic Search

RIASSUNTO. Sulla base di una metodologia consolidata, proposta in (26), per la definizione dell'intera curva di fatica di acciai mediante analisi termografica viene indicata una procedura per la valutazione del danno. Partendo dall'osservazione di base che ogni componente caricato dinamicamente, al di sopra del proprio limite di fatica, mostra un aumento di temperatura tanto più alto quanto più alto è

Antonino Risitano; Giacomo Risitano

2010-01-01

429

Impacto de las regalías petroleras en el Departamento del Meta  

Microsoft Academic Search

El departamento del Meta extrae petróleo crudo desde el año 1976, ubicándose, en la actualidad, entre los tres mayores productores del país. En consecuencia, con la influencia de su producción y las regalías, que han elevado el PIB departamental y fortalecido sus finanzas públicas, deben garantizarse amplías oportunidades de inversión, tanto pública como privada. El objetivo de este estudio es,

Germán Humberto Hernández Leal

2004-01-01

430

Inversiones en servicios públicos y dinámica del espacio urbano  

Microsoft Academic Search

El estudio de los servicios públicos constituye un campo en el que pueden examinarse la forma como la población satisface sus necesidades, los problemas y conflictos que se generan en el modo de producción, distribución y consumo, la relación entre el rol del Estado y las inversiones privadas en la satisfacción de esas necesidades y la construcción del espacio urbano.

Silvia Beatriz Grippo; Stella Maris Visciarelli

2007-01-01

431

Pastoral del Nino: Bringing the Abundant Life to Paraguayan Children  

ERIC Educational Resources Information Center

Pastoral del Nino is transforming children's lives in rural Paraguay. Part of Pastoral Social (Catholic Social Services), Pastoral del Nino's primary focus is to bring "vida en abundancia" (the abundant life) to families by ensuring that mothers survive childbirth and children reach their first birthdays. In addition, the organization promotes…

Austin, Ann Berghout; Aquino, Cyle; Burro, Elizabeth

2007-01-01

432

El comercio internacional en Colombia: una perspectiva diferente del TLC  

Microsoft Academic Search

La nueva teoría del comercio internacional deja de lado las diferencias entre los países en cuanto a recursos y se enfoca en las decisiones de los empresarios para presentar una visión alternativa de las implicaciones de la firma del Tratado de libre Comercio. La nueva teoría pone énfasis en la heterogeneidad de las empresas, en la relevancia de la productividad

Jan Ter Wengel; Luz Karine Ardila; Beatriz Ferreira Villegas; Luís Miguel Suárez Cruz

2007-01-01

433

EL COMERCIO INTERNACIONAL DE MÉXICO: ANTES Y DESPUÉS DEL TLCAN  

Microsoft Academic Search

El TLCAN trajo a México un alto pero breve crecimiento económico en sus primeros años de aplicación. En el pasado la economía y el comercio internacional del país estaba cimentado sobre la venta del petróleo crudo, teniendo una estabilidad importante en él, hasta el declive de sus precio en 1986, hoy en día el TLCAN a provocado un incremento sorprendente

Juan Antonio Herrera Izaguirre; Luis Hernán Lope Díaz; Alma Janeth Badillo Santes; Ramiro Aurelio Escobedo Carreón

2012-01-01

434

Conceptos fundamentales del desarrollo de proveedores (Caso de negocios 13)  

Microsoft Academic Search

El desarrollo de proveedores es una actividad que enriquece la gestión de la cadena de suministro, dotándola de mayor valor a través del aporte mutuo entre empresas clientes y subcontratistas. Este aporte incluye nuevas tecnologías, know-how, herramientas de la calidad y organización del trabajo, además de negociaciones sobre la política de precios, entre otros temas. En este trabajo presentamos sus

Enrique Yacuzzi

2012-01-01

435

[Escribir texto] DOBLE GRADO INGENIERA INFORMTICA -INGENIERA DEL SOFTWARE  

E-print Network

Desarrollo de Aplicaciones Web AIII 006 EAS Evolución y Adaptación del Software AIII 006 IA Inteligencia[Escribir texto] DOBLE GRADO INGENIERÍA INFORMÁTICA - INGENIERÍA DEL SOFTWARE Coordinador Informática - Ingeniería de Software 1er Semestre (Aulario III - Aula 002) Claves y profesores Clave

Rey Juan Carlos, Universidad

436

O Diagnostico do Curso de Farmacia da UNIMEP (Diagnosis of the Pharmacy Course of UNIMEP).  

ERIC Educational Resources Information Center

Reports on the experience of the pharmacy course at UNIMEP (Methodist University of Piracicaba (Brazil)) in diagnosing itself. Offers models for the elaboration of an innovative curriculum which is the desire of those who make up the course. (BT)

Fontes, Olney Leite; do Carmo, Thais Adriana; Polacow, Maria Luiza O.; Meneghetti, Rosa Gitana K.; Dedalo, Maria de Fatima Nepomuceno; Alves, Maria Izalina F.; da Silva, Jadson Oliveira; Carvalho, Maria Eliza C.

2000-01-01

437

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

Microsoft Academic Search

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

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

2004-01-01

438

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.

439

IMPORTANCIA Y VIGENCIA DEL PENSAMIENTO DE EDGAR MORÍN EN LA COMPRENSIÓN DEL CONOCIMIENTO. UNA VISIÓN DESDE LA PSICOLOGÍA  

Microsoft Academic Search

El presente artículo pretende exponer los diferentes retos que presentan la educación y el aprendizaje del siglo XXI mediante la exposición de las particularidades que presenta el conocimiento adquirido por el hombre a través de su historia. Se basa fundamentalmente en algunos planteamientos ofrecidos por Edgar Morín en su libro “Los siete saberes necesarios para la educación del futuro” ,

Mildreth Larquin Castillo

2011-01-01

440

Notas para el estudio del cambio social a comienzos del quinto ciclo de Kondratiev. Un marco teórico  

Microsoft Academic Search

El alza de los precios del pétroleo acontecida en 1973 puso fin a la más reciente fase de expansión del excepcional ciclo de crecimiento iniciado después de la segunda Guerra Mundial. Luego de un periodo tan largo e impresionante de bonanza -la producción industrial de los países de la OCDE se quintuplicó por ejemplo entre 1947 y 1973- era natural

Mauricio Rojas

1991-01-01

441

La metodologia de la valoracion contingente en la evaluacion de proyectos ambientales : el caso del saneamiento del Rio Medellin  

Microsoft Academic Search

Como consecuencia del crecimiento de las ciudades, se hace cada vez más sentida la necesidad de desarrollar proyectos de carácter ambiental que subsanen el efecto negativo del urbanismo y las grandes concentraciones poblacionales. Tal es el caso de los rellenos sanitarios y sistemas de alcantarillado y tratamiento de aguas residuales, entre otros. Sin embargo, los problemas de contaminación y saneamiento,

Fredy Zuleta D

1994-01-01

442

La biomedicina del segle XXI: nous paradigmes i noves responsabilitats dels científics  

Microsoft Academic Search

Tal com s'inverteixen cada cop més recursos a tot el món en recerca biomèdica i en\\u000aciències de la salut, també evoluciona la tradicional confiança de la societat en el progrés\\u000acientífic. Creixen les demandes de participació, d'eficàcia, de més aplicabilitat i d'impacte\\u000asocial dels recursos públics dedicats a la recerca, mentre que la professió de científic encara\\u000aconserva una

Jordi Camí i Morell

2012-01-01

443

[La Medicina del Lavoro: 100 volumes].  

PubMed

With these pages La Medicina del Lavoro starts its 100th volume, so we have yet another historical occasion to celebrate the oldest occupational health journal in the world that is still publishing. Over the last few years we have had many occasions to celebrate, for example several anniversaries of the Journal (the 80th volume in 1989, 90 years in 1992, 100 years in 2001); the centenary of the foundation of the Clinica del Lavoro "Luigi Devoto" of Milan in 2001; the celebration of the 300 years' anniversary of the publication of De Morbis Artificum Diatriba by Bernardino Ramazzini, and we obviously hope to continue for many years to come in this positive outlook. One hundred volumes makes for a very large collection, with the highs and lows ofthe Journal's history (here we mean the variations in number of pages and physical size of the Journal). It is thanks to the Editors-in-chief(there have been very few so we can cite them all: Luigi Devoto, 1901-1936; Luigi Preti, 1936-1941; Enrico Vigliani, 1943-1992; e Vito Foà, 1992 to the present); the contributors who in various ways and with varying degrees of commitment but always with an exceptional personal participation, that it has been possible to reach 100 volumes, starting with C. Moreschi who, along with Luigi Devoto, was the first and sole editor at the Journal's foundation; up to the present extended and impressive editorial board; the printers (from the first. Tipografia Cooperativa, Via dei Molini in Pavia, to the latest: Casa Editrice Mattioli in Fidenza); the sponsors, including the most evident who, via advertising (rather limited as a matter offact), directly gave information about themselves, but also those who have often been or are behind the scenes, ensuring fundamental support which is not visible; content. articles, news, events, reports, ideas, opinions, photographs, tables, numbers... etc, which are really impossible to sum up. But the true collection which, for obvious reasons, cannot be individually named, consists of the people and the ideas that have enriched the history of the Journal in its over 100 years of existence. And the subscribers, above all, who by their almost anonymous presence have been the true guarantors of the Journal's ife. And of course the contributors who with their articles have consigned a part of their lives to history. Starting from 1925 we counted nearly 11.000, a really grand number. It would be wonderful if we could invite them all to a hypothetical (and impossible) grand convention to simply say "Thank you, your contributions will not be forgotten". There have been 100 volumes but in actual fact the Journal is more than 100 years old. It was founded in Pavia in 1901 as Il Lavoro-Rivista di fisiologia, clinica ed igiene del lavoro, and between 1901 and 1910 only three volumes were published, then, due to the difficulties during the First World War and the immediate post-war years, there were no issues in 1916, 1918 and 1919. Issues finally became regular in 1920 with volume 11; from that moment on not one issue was missed and the Journal even got through the Second World War without interruptions. In 1925, with volume 16, it took on the name that still distinguishes it to-day: La Medicina del Lavoro, "the official standard bearer of a work of enormous scientific, social and political content" as Luigi Devoto presented the event at the time. The first few years of the Journal were difficult ones (with only three volumes published in 10 years) to the effect that events such as the First International Congress on Occupational Diseases (Milano, 1906), the foundation of the International Commission for Occupational Health (1906), the First National Italian Congress on Occupational Diseases (Palermo, 1907), and above all the inauguration of the Clinica del Lavoro in Milano (20 March, 1910) are not reported in the Journal, which by 1911 had resumed publication but had moved to Milan. Many years have passed since those first three volumes and in the meantime we have moved on to another century and

Zocchetti, C

2009-01-01

444

ACTUALIDAD INTERNACIONAL DEL TRATAMIENTO MAGNÉTICO PARA EL CONTROL DE INCRUSTACIONES. REVISIÓN  

Microsoft Academic Search

Luego de una breve descripción del proceso de endurecimiento del agua, se brinda una amplia información actualizada sobre la tecnología del tratamiento magnético del agua como método anti- incrustante en sistemas de intercambio de calor. Se destaca las principales hipótesis o mecanismos que pudieran responder a los efectos industriales observados, así como algunos de los resultados experimentales de los investigadores

Rigoberto del Toro Rodríguez; Arístides Berenguer Maurant

445

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.

446

S. ArgentiniS. Argentini ISAC CNR Area di Ricerca di Roma Tor Vergata,Via del Fosso del Cavaliere, 100 00133 Roma,ISAC CNR Area di Ricerca di Roma Tor Vergata,Via del Fosso del Cavaliere, 100 00133 Roma,  

E-print Network

S. ArgentiniS. Argentini 11 ISAC ­ CNR Area di Ricerca di Roma Tor Vergata,Via del Fosso del Cavaliere, 100 00133 Roma,ISAC ­ CNR Area di Ricerca di Roma Tor Vergata,Via del Fosso del Cavaliere, 100 00133 Roma, Italy,Italy, s.argentini@isac.cnr.its.argentini@isac.cnr.it SUMMARYSUMMARY The siteThe site

Ribes, Aurélien

447

UNIVERSIDAD NACIONAL AUTNOMA DE MXICO Datos del plan de estudio  

E-print Network

Futbol asociación Dirigido a: Entrenadores de la DGADyR, Comunidad Universitaria y Público General la técnica en el futbol para el grado ii III.- Técnica del portero aplicada al juego de conjunto a la

Islas, León

448

MEMORIA 2011 Torre de Control del antiguo aerdromo de Alicante  

E-print Network

MEMORIA 2011 Torre de Control del antiguo aeródromo de Alicante Nueva entrada a la UA enlace TRAM .........................................................................................................5 2.1 Resultados gestión de la calidad

Escolano, Francisco

449

Paso del Norte Watershed Council Coordinated Water Resources Database Project  

E-print Network

The Paso del Norte Watershed Council (PDNWC) is a quasi-governmental organization that serves in an advisory capacity to the New Mexico-Texas Water Commission regarding the selection, planning, and implementation of environmental enhancements...

Brown, Christopher; Sheng, Zhuping; Rich, Matt

450

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

451

Trasmissione numerica: Compito del 10/02/2011 Esercizio 1  

E-print Network

' AWGN con densita' spettrale di potenza media bilatera N0/2, i segnali hanno uguale prob- abilita' un rumore AWGN con densita' spettrale di potenza media bilatera N0/2. L'energia del segnale trasmesso

Abrardo, Andrea

452

77 FR 47360 - Del Norte Resource Advisory Committee  

Federal Register 2010, 2011, 2012, 2013, 2014

...authorized under the Secure Rural Schools and Community Self-Determination...the Del Norte County Unified School District, Redwood Room...Six Rivers National Forest Supervisor's Office, 1330 Bayshore...Six Rivers National Forest Supervisor's Office, 1330...

2012-08-08

453

DEPARTAMENTO DE INGENIERIA INFORMATICA Normativas para el Programa Doctorado del  

E-print Network

DEPARTAMENTO DE INGENIERIA INFORMATICA Normativas para el Programa Doctorado del Departamento de Valiente, 11. Madrid, 28049. Teléfono: 914972230 #12;DEPARTAMENTO DE INGENIERIA INFORMATICA 4. Una vez

Autonoma de Madrid, Universidad

454

FRAGOMEN, DEL REY, BERNSEN & LOEWY, LLP US IMMIGRATION CLIENT ALERT  

E-print Network

FRAGOMEN, DEL REY, BERNSEN & LOEWY, LLP US IMMIGRATION CLIENT ALERT If you have any questions about to the United States. This Client Alert provides general guidance on procedures, including visa issuance at U

Scharer, John E.

455

Sapienza Universit di Roma Direttore del Dipartimento: Prof. Fabio Grasso  

E-print Network

posseduti dai candidati alla data della scadenza del termine utile per la presentazione delle domande di quale inviare ogni comunicazione, ivi comprese le convocazioni per il colloquio, senza che vi sia altro

Guidoni, Leonardo

456

Facultad de Estudios Superiores Acatln Datos del plan de estudio  

E-print Network

Dirigido a: Profesionales que deseen desarrollarse en las áreas de comercio internacional, gestión aduanera y negocios internacionales. Empresarios relacionados al comercio internacional. Personas interesadasFacultad de Estudios Superiores Acatlán Datos del plan de estudio Diplomado: Comercio exterior

Islas, León

457

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

458

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

459

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

460

Mecanica del Solido Deformable Presentacion de la asignatura  

E-print Network

Mec´anica del S´olido Deformable Presentaci´on de la asignatura Profesor Ignacio Romero E consulta (en la biblioteca): -- Introducci´on a la mec´anica de los s´olidos. Zubizarreta, V. y Ros, A asignatura 6 · La Mec´anica de S´olidos trata del estudio de modelos de comportamiento de s

Romero, Ignacio

461

La construccin del discurso en el siglo XIII  

E-print Network

« literarios », y, por otro, de las « creencias », más que « ideas », acerca de cómo evoluciona la sintaxis en « supraoracional », y cae bajo el análisis del discurso, más que de la sintaxis tradicional). 1.1. Las creencias suma, no usa la subordinación sintáctica, porque le bastan otros medios3, creencia nacida además del

Paris-Sud XI, Université de

462

Pedro, Juan y Diego: Obra fundacional del teatro contestario chileno  

E-print Network

paradigma en la adquisición de bienes de consumo y su sueño máximo era el vehículo propio. Para materializar este sueño los individuos debían ingresar al sistema de relaciones típicas del mundo impersonal del dinero, priorizando la competitividad y... Austin Mini-Toyota-Frigidaire... ¡Super compacta! ¡Una verdadera proeza de la tecnología nipona!" (102). Diego tenía una sociedad con otros ex-compañeros, todos desempleados ahora, que alimentaban este sueño que veía ya como imposible. El vehículo iba...

Lepeley, Oscar

2001-04-01

463

Aspectos clínicos de la biología molecular del cáncer de próstata  

Microsoft Academic Search

Resumen  La tecnología del ADN recombinante ha sido una herramienta invaluable para entender los mecanismos de carcinogénesis. Por\\u000a ejemplo, hemos podido conocer que en nuestro propio genoma existen genes con la capacidad de inducir transformación maligna\\u000a (oncogenes) on con la capacidad de bloquearla (genes supresores de tumores). Esta tecnología también nos ha permitido desarrollar\\u000a nuevas estrategias de diagnóstico y tratamiento del

Diana González-Espinosa; Miguel A. Jiménez Ríos; Andrés A. Gutiérrez-López

2002-01-01

464

La generación de 1924: El dilema del realismo  

E-print Network

, Celestino Gorostiza, repite sólo en parte esta trayectoria que estamos esbozando. Sus primeras obras reflejan intereses intelectuales típicos del momento. El nuevo paraíso (1930) recuerda los Autos de Villaurrutia en su visión de un Edén abstracto en el... dentro de las convenciones de su tipo: mucho movimiento, exageración, bailarinas en mallas, chanzas al arte abstracto, y moraleja final. La sátira halla sus blancos en diversos sectores de la vida publica y privada, tales como la corrupción del...

Dauster, Frank

1985-04-01

465

Del carnaval como 'metáfora' al teatro de carnaval  

E-print Network

la década de 1980) persigue contribuir al desarrollo de una manera más productiva de visualizar el teatro del carnaval, y en general, la práctica teatral en la actualidad. Actuación de la Anti-Murga BCG en el tablado "El Monumental del Control... funcionalizadas año tras año con ese fin. El escenario, el panel de fondo (comercial o alegórico), los asientos, la boletería, las paredes circundantes, se construyen de chapas, bloques y tablones. Cables y lamparitas colgantes, letreros, pintadas y graffitis...

Remedi, Gustavo

2001-04-01

466

Aportació a coneixement florístic del Moianès (Catalunya central)  

Microsoft Academic Search

Seguint en la línia d'ampliació del coneixement florístic de l'àrea del Moianès, presentem dades d'interès corològic de 46 tàxons. Es tracta bàsicament d'espècies d'ambients forestals i pradencs, bona part no citades d'aquest sector i algunes de molt rares o inexistents al territori ausosegàrric. Hi ha un primer grup d'espècies, que a les terres catalanes són bàsicament pirinenques [Linum viscosum L.,

Arnau Mercadé López

2007-01-01

467

Osservazioni sulla morfo-biologia del Pnigalio mediterraneus Ferr. & del. ( Hym. eulophidae )  

Microsoft Academic Search

\\u000a Résumé  L'Auteur confirme les observations deSilvestri concernant la polyphagie de l'espècePnigalio mediterraneus\\u000a Ferr. etDel. Le parasite attaque en Italie aussi bienLithocolletis millierella\\u000a Stgr. etL. blancardella\\u000a F., queDacus oleae\\u000a Gml. Il se développe aux dépens de mineuses de feuilles au printemps et attaque de préférence leDacus en été et en automne. L'auteur découvre ensuite que lePnigalio en question peut être un parasite

G. Viggiani

1963-01-01

468

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

E-print Network

, sino mediante una amplia plasmacion del ser, mediante la presentaci6n de c6mo las ideas, los sentimientos y los modos de actuar nacen de cate terreno historico" (Lukacs, 54). Este concepto de la autenticidad y la fidelidad historicas supone que... vision no menos real, pese a no ser "documentable" en el sentido estricto. La novels historica ha sufrido ataques de parte de los historiadores con respecto a los errores y el desconocimiento de la epoca que los novelistas pretendian recrear, mientras...

Loeffler, Lisa Bowe

1984-01-01

469

Futuras fuentes de crecimiento de la productividad del trigo en la region del Baj?o (Guanajuato, Mexico)  

Microsoft Academic Search

El objetivo de esta investigaci?n es determinar la perspectiva de la producci?n de trigo en la regi?n del Baj?o (Guanajuato, M?xico), como una zona estrat?gica para proveer la materia prima que requiere la industria molinera de la zona centro del pa?s. Se determin? el comportamiento de los componentes de la producci?n mediante el c?lculo de las tasas de crecimiento. Asimismo,

Pedro Aquino-Mercado

2003-01-01

470

La judicializacin del caso de la pldora del da despus en Chile: las tensiones sobre el rol de la mujer y la cuestin tcnica1  

E-print Network

que serán supeditadas al contexto social en cual la política se inscribe. Introducción El Chile de la1 La judicialización del caso de la píldora del día después en Chile: las tensiones sobre el rol de en torno a la introducción de la píldora del día después en Chile. Esta discusión se posicionó en la

Paris-Sud XI, Université de

471

Componentes naturales y de uso del suelo vulnerables a las variaciones del nivel del mar en la costa atlántica de México  

Microsoft Academic Search

Palabras clave Regionalizaci6n de costas, fislografia, vulnerabilidad costera, uso del suelo Absúact Geomorphological alaradenstia of the mastal iongitudinal prn* and the arrangwent of the physiographical stmcture allowed the rmnition of two zonas: a) the intertidai zone -a basic sntne for dired imoaci of sea leve1 dame: and b) an adjacent peritidál (supralittoral) hnge &n area of cushioning or of polential

Mano Arturo; Ortiz Pérez; Ana Patricia; Méndez Linares

472

LOS NIVELES EMPÍRICO Y TEÓRICO DEL CONOCIMIENTO Y LA UTILIZACIÓN DEL MÉTODO HISTORICO LÓGICO EN LA FUNDAMENTACIÓN DEL APORTE TEORICO DE UNA TESIS DOCTORAL  

Microsoft Academic Search

En su función de tribunal y oponente a variadas tesis doctorales desarrolladas en los últimos tiempos se ha constatado, por los autores de este trabajo, algunos problemas en la aplicación de los métodos del pensamiento científico que dificultan a los aspirantes definir y defender los aportes fundamentales de sus investigaciones. A tono con estas situaciones a aparecido para los jóvenes

Miguel Erasmo; Zaldívar Carrillo; Samuel Oliveros Calderón

2008-01-01

473

Utilidad diagnóstica del Cuestionario TDAH y del Perfil de Atención para discriminar entre niños con tratorno por déficit de atención con hiperactividad, trastornos del aprendizaje y controles  

Microsoft Academic Search

Se analiza la convergencia entre la información recogida de padres y profesores, mediante escalas de valoración, y el diagnóstico clínico en una muestra de 126 niños: 42 con Trastorno por déficit de atención con hiperactividad (TDAH) tipo combinado, 21 con Trastornos del aprendizaje (TA) y 63 controles, con edades comprendidas entre los 4 y los 12 años. El grupo de

Juan Antonio Amador; Maria Forns; Joan Guàrdia Olmos; Maribel Peró

2005-01-01

474

Peat soil flows in Bahía del Buen Suceso, Tierra del Fuego (Argentina)  

NASA Astrophysics Data System (ADS)

On the southeastern edge of Tierra del Fuego, a mountainous area with a cold humid oceanic climate, peat soils cover not only flat areas but also steep hillslopes under an evergreen Nothofagus betuloides forest. Peat flows in the form of chutes are very frequent on these hillslopes. Some data were gathered on the field for 11 of these movements and from aerial photographs for 21 of them. The results suggest that peat soils become unstable when thickness exceeds a critical value which depends on the slope. This critical slope depends on the altitude and aspect regardless of soil thickness. A temporal analysis carried out by tree-ring counting demonstrated that the occurrence of these movements is not random though there are some periods of higher hazard, the probable triggering mechanisms being heavy snowfalls or earthquakes.

Gallart, Francesc; Clotet-Perarnau, Núria; Bianciotto, Oscar; Puigdefàbregas, Joan

1994-05-01

475

Mild phenotype in a patient with mosaic del(8p)/inv dup del(8p).  

PubMed

We report on a female with a mild phenotype who is mosaic for two cell lines with different structural abnormalities of 8p, both resulting in large genomic imbalances. Molecular cytogenetic and G-banded chromosome analyses demonstrated that one cell line has a large terminal 8p deletion, with a breakpoint in 8p21.2. The other cell line contains a derivative chromosome 8, known as an inv dup del(8p) in the literature. This female has developmental delay, but lacks congenital anomalies that are associated with either 8p abnormality in non-mosaic form. The attenuated phenotype in this individual may be due to compensation of one cell line for imbalances in the other cell line. PMID:20830805

Hand, Matthew; Gray, Carolyn; Glew, Gwen; Tsuchiya, Karen D

2010-11-01

476

PIANO DI RIQUALIFICAZIONE AMBIENTALE E PAESAGGISTICA DEL TERMOVALORIZZATORE DI DESIO TERMOVALORIZZATORE DI DESIO (MI) BRIANZA ENERGIA E AMBIENTE SPA  

E-print Network

PIANO DI RIQUALIFICAZIONE AMBIENTALE E PAESAGGISTICA DEL TERMOVALORIZZATORE DI DESIO Febbraio 2007 #12;PIANO DI RIQUALIFICAZIONE AMBIENTALE E PAESAGGISTICA DEL TERMOVALORIZZATORE DI DESIO Architecture Nature Development Febbraio 2007 #12;PIANO DI RIQUALIFICAZIONE AMBIENTALE E PAESAGGISTICA DEL

Columbia University

477

El Sexto Festival de Teatro Español del Siglo de Oro  

E-print Network

lindo don Diego, Compañía Pequeño Teatro de Madrid, España. La dama duende, Compañía Pequeño Teatro de Madrid, España. (Fuera de concurso) La cena del rey Baltasar, Escuela de Bellas Artes de la Universidad Autónoma de la ciudad de Chihuahua, Mé- 80... paso de las aceitunas, entremés en Casa con dos puertas, mala es de guardar, y Luis E. Julia por la música de la misma obra. Categoría B (No profesional) Mejor producción: , La cena del rey Baltasar, Escuela de Bellas Artes, Universidad Autónoma de...

Pé rez-Pisonero, Arturo

1981-04-01

478

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

E-print Network

, Perú y Venezuela); 1 de Estados Unidos; 2 de Japón, y 2 de Africa (Nigeria y Túnez). Además de los grupos de teatro propiamente dichos, y paralelamente a sus funciones en 11 salas del centro y la periferia de la capital, se organizaron una infinidad... teatristas y amigos del arte dramático a partir de la medianoche cuando ter minaba la última función en las salas de la ciudad. Era tal el número de gru pos teatrales y conjuntos musicales invitados a participar que, a más de las dos sesiones ordinarias de...

Má rceles Daconte, Eduardo

1981-10-01

479

Photometric study of the binary system NN Del  

NASA Astrophysics Data System (ADS)

We present the results of the differential V light curve analysis of NN Del. We show that NN Del is an EA eclipsing binary system with a period of 99.27 days and a highly eccentric orbit. Photometric solutions obtained using the Russell and the Wilson-Devinney models seem to indicate that both components are very similar in radii and luminosities (assuming a F5 spectral type). Constraints imposed on the V luminosity of the system by the HIPPARCOS data suggest that the components of the system could be subgiants instead of main sequence stars.

Gómez-Forrellad, J. M.; Sánchez-Bajo, F.; Corbera-Subirana, M.; GarcÍa-Melendo, E.; Vidal-Sainz, J.

480

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.

481

Un análisis diferenciador del teatro de Virgilio Piñera: El teatro satírico burlesco y el teatro absurdista  

E-print Network

Jesús, de 1948, y Falsa alarma Pinera "se adelanta a algunos dramáticos europeos de su momento al utilizar recursos y temas del teatro del absurdo."4 Estas afirmaciones de los críticos parecen discrepar un tanto con las declaraciones que el mismo... realidad absurda que se dramatiza. Incluso en Electra Garrigó y Jesús, que son las únicas obras que acusan cierta preocupación metafísica, a la hora de categorizarias se hace difícil encuadrarlas dentro de la fisonomía del teatro del absurdo. En la...

Jerez Farrá n, Carlos

1989-04-01

482

La reescritura de Juan Moreira: La política del decorum en el teatro argentino  

E-print Network

periódicos y las revistas que publicaron historias como la de Juan Moreira, no sólo devaluaron los modelos que la "cultura letrada" había construido desde 1810 (mediante agrupaciones como la Sociedad del Buen Gusto del Teatro, fundada en 1811), sino que... exclusiva de los letrados. El control del libro no garantizaba el control del periódico y el periódico servía para que se introdujera un nuevo tipo de libro al gusto de un pueblo recién alfabetizado. El sistema literario promovido por la cultura letrada...

Podestá , Guido A.

1991-10-01

483

Prcticas de Evaluacin del Impacto Ambiental Revisin de Estudios de Impacto Ambiental  

E-print Network

Prácticas de Evaluación del Impacto Ambiental Revisión de Estudios de Impacto Ambiental Nombre y/salidas en términos de vertidos/recursos? C.- El Inventario Ambiental: - ¿Incluye todos los factores del? #12;Prácticas de Evaluación del Impacto Ambiental D.- La identificación de impactos: - ¿Qué método

Espigares, Tíscar

484

La Europa del Este en la historiografía española de las relaciones internacionales  

Microsoft Academic Search

La crisis del sistema del socialismo real y consiguiente caída de regímenes comunistas en Europa del Este, la desintegración de la Unión Soviética y la ruptura y guerra en la Federación Yugoslava han obligado a los historiadores y demás especialistas en estas cuestiones a revisar sus planteamientos sobre el origen y evolución de dicho sistema y a ampliar además los

Ricardo M. Martín de la Guardia; Guillermo Á. Pérez Sánchez

2001-01-01

485

Trayectorias tecnológicas de las máquinas térmicas e industrial del motor en España  

Microsoft Academic Search

En este trabajo se pretende analizar los diversos paradigmas y trayectorias tecnológicas relacionados con las máquinas térmicas a lo largo del siglo XIX y primeras décadas del XX para reflexionar sobre la dinámica evolutiva y lógica interna del propio proceso de innovación en el sector, sobre la participación española en el mismo y sobre el impacto específico de los avances

J. Patricio Saiz; R. Rubén Amengual

2005-01-01

486

UNIVERSIT DEGLI STUDI DI TORINO ISTRUZIONI PER LA COMPILAZIONE ON LINE DEL PIANO CARRIERA  

E-print Network

1 UNIVERSITÀ DEGLI STUDI DI TORINO ISTRUZIONI PER LA COMPILAZIONE ON LINE DEL PIANO://www.unito.it Per accedere alla funzionalità di presentazione del piano carriera devi accedere con le credenziali://www.unito.it/unitoWAR/page/istituzionale/istruzioni/P35407898381252672659560. 2. Compilazione del Piano Carriera Effettuato il login accedi al menù Segreteria

Sproston, Jeremy

487

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

E-print Network

VIH debe también ligarse a las proteínas CCR5 ó CXCR4 (co- receptores) para entrar en la célula receptor CD4 glucoproteína del VIH envoltura del VIH CCR5 receptor o CXCR4 receptor Un servicio del

Levin, Judith G.

488

Análise de esteiras microbianas e cianobactérias da laguna Amarga, Parque Nacional de Torres del Paine, Chile  

Microsoft Academic Search

ANALYSIS OF MICROBIAL MATS AND CYANOBACTERIA FROM THE LAGUNA AMARGA, TORRES DEL PAINE NATIONAL PARK, CHILE. This study is based on cyanobacterial and sedimentary investigations of the microbial mats formed at Laguna Amarga, located at the southernmost part of South America, specifically in the Chilean Torres del Paine National Park. The Torres del Paine's natural and geological richness is composed

Loreine Hermida da Silva

489

P/P/P/P/20202020 D.R. n.D.R. n.D.R. n.D.R. n. n. 5024 del 1.08.2011n. 5024 del 1.08.2011n. 5024 del 1.08.2011n. 5024 del 1.08.2011  

E-print Network

1.08.2011n. 5024 del 1.08.2011 ClasseClasseClasseClasse LM-6 - Biologia Nome del corsoNome del corso/2010, art. 14) 12 Obiettivi formativi qualificanti della classe: LM-6 Biologia I laureati nei corsi di biologia di base e nei diversi settori della biologia applicata e un'elevata preparazione scientifica e

Malerba, Donato

490

EL COMERCIO ELECTRÓNICO Y EL FUTURO DEL CANAL DE DISTRIBUCIÓN TURÍSTICO  

Microsoft Academic Search

RESUMEN Dentro de las implicaciones que el desarrollo de las nuevas tecnologías pueden tener sobre la eco- nomía, merece especial importancia el impacto que Internet y el comercio electrónico tienen sobre la estructura del canal de distribución, a través del cual las empresas ponen sus productos y servi- cios a disposición del mercado. En lineas generales se prevé que el

Sellers Rubio; R. Azorín Escolano

2001-01-01

491

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.

492

Spectral Characterization of Volcanic Earthquakes at Nevado del Ruiz Volcano Using  

E-print Network

Spectral Characterization of Volcanic Earthquakes at Nevado del Ruiz Volcano Using Spectral Band methods in a two-class classification problem of volcanic earthquakes recorded at Nevado del Ruiz Volcano, seismic-volcanic events, spectral analysis. 1 Introduction Nevado del Ruiz is an ice-capped volcano placed

Duin, Robert P.W.

493

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

494

Medidas no financieras del rendimiento en la empresa: fundamentos, métodos y una aplicación  

Microsoft Academic Search

Describimos y fundamentamos la tendencia creciente a utilizar medidas no financieras para la medición del rendimiento empresarial (business performance measurement), así como una axonomía de estas medidas y el impacto del movimiento de la calidad total en las prácticas de medición. Las medidas que presentamos se caracterizan por (1) medir la productividad y la calidad desde la perspectiva del cliente;

Enrique Yacuzzi

2006-01-01

495

INFLUENZA DEL VALOR MEDIO SUL DANNEGGIAMENTO A FATICA IN SOLLECITAZIONI RANDOM  

Microsoft Academic Search

Sommario La presente memoria affronta il problema della stima dell'effetto del valor medio dei cicli rainflow nel calcolo del danno in un processo random stazionario ) (t X mediante metodi in frequenza. Sono presentati due approcci di complessità crescente: nel primo, si valuta il solo effetto del valor medio complessivo c m della sollecitazione, mentre nel secondo si include anche

D. Benasciutti; R. Tovo

496

EVOLUCIÓN DEL SERVICIO DE ACUEDUCTO Y ALCANTARILLADO DURANTE LA ÚLTIMA DÉCADA  

Microsoft Academic Search

Este documento presenta un análisis de los efectos de las reformas introducidas por la Constitución de 1991 y por la Ley 142 de 1994 sobre el desempeño del sector de agua potable y saneamiento básico. Incluye una descripción de esas reformas y del actual marco institucional y regulatorio del sector. El documento analiza la evolución de las realidades institucionales y

Carolina Domínguez; Eduardo Uribe

2005-01-01

497

PERFIL SOCIOECONÓMICO DEL MUNICIPIO DE SAN ANTONIO NANAHUATIPAM EN EL ESTADO DE OAXACA 2008  

Microsoft Academic Search

La Universidad Autónoma “Benito Juárez” de Oaxaca, a través de la Agencia de Desarrollo ha establecido el vínculo institucional en diversas comunidades del estado, para conocer los problemas que se dan en cada una de ellas y que no permiten su desarrollo. Es importante mencionar que a pesar del avance tecnológico en todas las ciudades del mundo, en México y

Ana Luz Ramos Soto

2008-01-01

498

in collaborazione con: Sovraintendenza ai Beni Culturali del Comune di Roma  

E-print Network

in collaborazione con: Sovraintendenza ai Beni Culturali del Comune di Roma con il patrocinio di l'Università `La Sapienza' di Roma ed ha come obiettivo la formazione del lighting designer e del-Tokyo, Artemide-Dubai, Regent-Basilea, Studio Fabertechnica S.a.S-Roma, Studio Annunziata&Terzi-Roma, Studio GMS

Di Pillo, Gianni

499

DD. 81/2014 del 22/07/2014 (Bando RTD n. .2_2014)  

E-print Network

Consiglio di Dipartimento del 12/02/2014; Visto il parere Favorevole del Collegio dei Revisori reso in data-dottorato. I suddetti requisiti devono essere posseduti alla data della scadenza del termine utile per la personale al quale inviare ogni comunicazione, ivi comprese le convocazioni per il colloquio, senza che vi

Roma "La Sapienza", Università di

500

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.